SOUTHEAST ARIZONA FORECAST DISCUSSION...CORRECTED DATE NATIONAL WEATHER SERVICE TUCSON AZ 807 AM MST TUE MAR 21 2000 SYNOPSIS...UPPER LEVEL LOW PRESSURE HAS BECOME STALLED OVER ARIZONA AND WILL KEEP THE WEATHER UNSETTLED THROUGH WEDNESDAY NIGHT. DRY AIR HAS TEMPORARILY WRAPPED INTO THE SYSTEM...BUT AS MORE MOISTURE IS PULLED BACK IN THIS AFTERNOON AND EVENING...CLOUDS AND SCATTERED SHOWERS WILL REDEVELOP. THE STORM WILL ALSO KEEP TEMPERATURES BETWEEN 10 AND 15 DEGREES BELOW NORMAL BEFORE IT DEPARTS ON THURSDAY AND ALLOWS HIGH PRESSURE TO DEVELOP OVER THE REGION. DISCUSSION...CUTOFF LOWS ARE ALWAYS MESSY, AND THIS ONE IS NO EXCEPTION. AFTER PICKING UP SOME SPOTTY DUSTINGS AS LOW AS 4KFT LAST NIGHT EAST OF TUCSON, HUGE DRY SLOT NOW COVERS THE ENTIRE SOUTHERN 1/2 OF AZ THIS MORNING. MOUNTAIN DEWPOINTS HAVE BEEN FALLING WHICH TELLS ME THAT EVEN THOUGH WE HAVE DECENT UPSLOPING, DENDRITIC GROWTH IS BECOMING INEFFICIENT SINCE THE -15C LAYER IS UNSATURATED. WE'LL DROP ADVISORY FOR NOW, BUT AS WRAPAROUND GETS BETTER ESTABLISHED, WE MAY NEED TO HOIST IT AGAIN LATER. YUMA SOUNDING IS VERY DRY BELOW 700MB WHERE SATELLITE SHOWS SOME WRAP-AROUND SNEAKING IN. 700-500MB LAPSE RATES ARE VERY STEEP BUT WITH SO MUCH DRY AIR BELOW, ANY SHOWERS THAT REGENERATE WILL HAVE A HARD TIME REACHING THE GROUND UNTIL AFTER DARK. INVERTED-V SOUNDING INDICATES SOME VIRGA MICROBURST POTENTIAL WHICH WE'LL HANDLE IN NOWCASTS AS NEEDED. 12Z UPPER AIR SHOWS A 130KT SPEED MAX ROTATING AROUND THE UPPER LOW OVER NV WHICH 12Z RUC SWINGS ACROSS AFTER 00Z. 12Z SOUNDINGS INDICATE THAT IF LOW LEVEL DEWPOINTS CAN MAKE A JUMP THIS EVENING WITH THIS FEATURE, WE'LL HAVE TO WATCH OUT FOR LOW-TOPPED TSTMS WITH SMALL HAIL. WE HAVE SOME TIME TO SEE HOW THINGS DEVELOP THROUGH EARLY AFTERNOON BEFORE HAVING TO MAKE ANY ADDITIONAL MOVES. PYTLAK .TWC...NONE. az SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 842 PM MST TUE MAR 21 2000 A QUICK UPDATE ON THE POTENTIAL WINTER WEATHER SITUATION. LATEST WATER VAPOR/IR SATELLITE IMAGERY SHOWED DEEP AND MEANDERING LOW PRESSURE CENTER ALONG THE AZ/OLD MEXICO BORDER WITH PARENT ULJ ROTATING TOWARDS THE BASE OF THE LOW. EXPLOSIVE COOLING IR ENHANCEMENT ACROSS CENTRAL 1/3 OF NM IN THE FAVORED LARGE SCALE ASCENT AREA OF THE ULJ LEFT FRONT EXIT REGION. REGIONAL WSR- 88DS SHOWED AREA OF PRECIPITATION IN CENTRAL NM HEADING NORTHWARD. LATEST ETA/NGM/RUC ALL SUGGESTING 500MB LOW TO TRACK ALONG THE AZ/OLD MEXICO BORDER TONIGHT INTO WED. NEW NGM RIGHT IN-LINE WITH NEW ETA. COULD BE NGM'S NEW INITIALIZATION WITH THE MESO-ETA. IN FACT...THE ETA AND NGM ARE NEARLY MIRROR IMAGES THROUGH 48 HOURS. DON'T SEE THAT TOO OFTEN. AVN NOT IN JUST YET AND WOULD LIKE TO SEE. BIAS WOULD BE A TOUCH FURTHER NORTH...WILL SEE. TRACK WILL BE CRUCIAL AS THE ASSOCIATED LARGE SCALE ASCENT WILL BE SOUTH OF THE CWFA AT LEAST FOR TONIGHT. LATEST MODELS KEEP THE STRONGEST LARGE SCALE ASCENT JUST SOUTH OF CO PER 700-500MB DIV TOTAL Q TONIGHT. ALSO...THE DEEPENING AND STRENGTHENING OF THE EASTERLY UPSLOPE FLOW FOR THE SOUTHEAST MOUNTAINS AND PLAINS COULD HOLD OFF UNTIL WED. BEST UPSLOPE FLOW MAY BE IN THE EXTEME SOUTHERN SANGRE DE CRISTO MOUNTAINS TOWARDS SUNRISE. LATEST MODELS DO MOISTENING THINGS UP FOR WED WITH THE STRONGEST LARGE SCALE ASCENT AND WEAK UPSLOPE ACROSS SOUTHERN CO/NM. THIS IS IN RESPONSE TO A MID-LEVEL SHORTWAVE TROUGH ROTATING INTO EASTERN NM EARLY WED. THINGS REALLY DON'T APPEAR FULLY JUXTAPOSED FOR A MAJOR EVENT FOR WED...BUT THINGS COULD CHANGE. LATEST MODELS DON'T EVEN PRINT OUT ANY QPF TONIGHT FOR MUCH OF THE CWFA...EXCEPT ALONG CO/NM BORDER. BEST THREAT FOR SNOWFALL APPEARS FOR TONIGHT APPEARS TO BE IN THE SAN LUIS VALLEY AND SOUTHWEST MOUNTAINS. NOT SURE HOW DEEP CLOUD MASS IS PER SATELLITE IMAGERY. NO REPORTS OF SNOW COMING INTO THE OFFICE FOR THESE AREAS...YET. AS FOR CURRENT WINTER STORM WATCH IN SANGRE DE CRISTO AND WET MOUNTAINS. GIVEN MUCH WINTER STORM EVOLUTION UNCERTAINTIES...WILL CONTINUE WATCH AND NOT LOCK IN MIDSHIFT ON SNOW AMOUNTS. HOPEFULLY... LATER RUC MODEL RUNS...REGIONAL RADAR...AND SATELLITE IMAGERY WILL ASSIST THEM IN EITHER ISSUING A WARNING...ADVISORY....OR CANCELLATION. WILL ALSO NEED TO TRIM OR PUSH BACK POPS FOR THE PLAINS... ESPECIALLY COS AND NORTHERN PORTION OF CWFA. .PUB...WINTER STORM WATCH ZONES 65/66/70 LATE TONIGHT AND WEDNESDAY. METZE co SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 300 AM MST TUE MAR 21 2000 ...MAIN FORECAST PROBLEMS CONTINUE TO BE SNOWFALL AMOUNTS... UPPER LEVEL LOW CONTINUES TO SPIN OVER ARIZONA AND IT IS PROGGED TO REMAIN NEAR STATIONARY OR MOVE A LITTLE SOUTHWEST TODAY. SATELLITE AND RADAR MOSAIC CONTINUE TO SHOW A BAND OF SIGNIFICANT PRECIPITATION DEVELOPING OVER CENTRAL NEW MEXICO AND MOVE NORTH. EVEN KPUX SHOWING SOME RETURNS OVER 16 DBZ BETWEEN TAOS AND CUMBRES PASS...AND THERE WERE A FEW LIGHTNING STRIKES IN THIS BAND. ETA AND RUC SHOW UPPER LEVEL FORCING TO CONTINUE THROUGH MOST OF THE AFTERNOON OVER THESE REGIONS AS SEEN IN THE 200-300MB DIV Q. BASED ON THE FORCING AND CONTINUED DEVELOPMENT OF THE BAND OF PRECIPITATION...WE WILL CONTINUE THE WINTER STORM WARNING FOR ZONES 60 AND 61. IT LOOKS LIKE THE BAND WILL ALSO STRIKE THE WESTERN PORTION OF THE SAN LUIS VALLEY AND WE WILL UPGRADE THE ADVISORY IN ZONES 62 TO 64 TO A WARNING. ANTONITO SPOTTER CALLED WITH 6 INCHES OF SNOW AT 2AM. THE WIND DIRECTION IS PARALLEL TO THE ARKANSAS VALLEY IN ZONE 69 (CHAFFEE COUNTY). KPUX HAS BEEN SHOWING ECHOES OVER SALIDA MUCH OF THE NIGHT. SOUTH SOUTHEAST FLOW AND SYNOPTIC LIFT REMAINING THROUGH MUCH OF THE DAY...WE WILL CONTINUE THE WARNINGS FOR ZONES 59 AND 69 AS WELL AS THE ADVISORY FOR ZONE 58. THE REMAINING FORECAST PROBLEM IS WHAT TO DO WITH THE EAST SLOPES OF THE SOUTHEAST MOUNTAINS AND ADJOINING PLAINS. THE FLOW ON THE EASTERN PLAINS CONTINUES TO BE FROM THE NORTH NORTHEAST FROM JUST ABOVE THE SURFACE TO BARRIER TOP. SNOW HAS BEEN STEADILY FALLING ON THE EAST SLOPES OF THE SOUTHEAST MOUNTAINS AND ADJOINING PLAINS DURING THE EVENING. SNOWFALL RATES ARE NOT EXCEPTIONAL...BUT SOME AMOUNTS NEAR WARNING CRITERIA HAVE BEEN REPORTED IN WALSENBURG...CUCHARA AND RYE. A JET STREAK IS CURRENTLY ROUNDING THE CUT OFF LOW AND WILL MOVE NORTHEAST INTO NORTHEAST NEW MEXICO DURING THE MORNING. THE RUC AND ETA POSITIONS AGREE FAIRLY WELL WITH DRYING IN WATER VAPOR. THE SOUTHEAST MOUNTAINS WILL BE IN THE LEFT EXIT REGION OF THE JET. WITH THE ADDITIONAL LIFT OVER THE SOUTHERN MOUNTAINS...THE RUC HAS THE LOW LEVEL FLOW ON THE PLAINS BECOMING MORE EASTERLY AND INTENSIFYING. THIS SHOULD RE-INTENSIFY THE SNOW DURING THE MORNING HOURS. GIVEN THE NEAR WARNING CRITERIA SNOWFALL ALREADY RECEIVED AS WELL AS INCREASE IN FORCING...WE WILL CONTINUE THE WARNING FOR ZONES 65-66-68-70-74-75. ZONES 67...71 AND 72 WILL BE A BIT NORTH OF THE BEST DYNAMICS. WITH THE NORTHERLY FLOW CONTINUING...I WILL DOWNGRADE THE WARNING IN 67 AND 72 TO A SNOW AND BLOWING SNOW ADVISORY. ZONE 71 IS NOT VERY FAVORABLE WITH NORTH FLOW AND WE WILL CANCEL THE WARNING. NOT MUCH SNOW HAS ACCUMULATED IN ZONES 73...76 AND 77 DUE TO WARMER TEMPERATURES. WE WILL CANCEL THE ADVISORY FOR THESE ZONES AS WE DO NOT EXCEPT MAJOR ACCUMULATIONS. FOR TUESDAY NIGHT AND INTO EARLY WEDNESDAY...UPSLOPE FLOW CONTINUES WITH WEAK FORCING AND CURRENT FORECASTS LOOKS REASONABLE. ON WEDNESDAY NIGHT...UPPER LOW BEGINS MOVING NORTH EAST AND WILL PASS OVER COLORADO SOMETIME ON THURSDAY. WITH PLENTY OF LOW LEVEL MOISTURE...ANOTHER ROUND OF PRECIPITATION IS EXPECTED. WITH SPEED OF SYSTEM AND MODEST SNOWFALL AMOUNTS IN SOUTHEAST MOUNTAINS...THE HYDROLOGIC CONCERNS FOR THURSDAY HAVE BEEN GREATLY REDUCED. FRIDAY AND SATURDAY LOOK TO BE GENERALLY QUIET. IF THE MRF RUNS OF THE PAST TWO DAYS ARE ACCURATE...WE SHOULD REMAIN BUSY NEXT WEEK. THANKS TO GJT AND BOU FOR COORDINATION. WOLYN .PUB...WINTER STORM WARNING TODAY FOR ZONES WESTERN CHAFFEE COUNTY (ZONE 59) SOUTHWEST MOUNTAINS (ZONES 60 AND 61) SAN LUIS VALLEY (ZONES 62>64) WESTERN FREMONT AND NORTHERN CUSTER COUNTIES (ZONE 68) UPPER ARKANSAS RIVER VALLEY (ZONE 69) SANGRE DE CRISTO AND WET MOUNTAINS (ZONES 65-66-70) UPPER PURGATOIRE AND HUERFANO RIVER BASINS (ZONES 74-75) SNOW AND BLOWING SNOW ADVISORY FOR TODAY FOR EASTERN LAKE COUNTY (ZONE 58) NORTHERN EL PASO COUNTY (ZONE 72) PIKE PEAK/RAMPART RANGE (ZONE 67) co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KEY WEST FL 905 PM EST TUE MAR 21 2000 CURRENTLY... IR SATELLITE AND METAR REPORTS INDICATE BROKEN TO OVERCAST HIGH-BASED STRATOCUMULUS (IN A LAYER 6-7 THSD FT AGL) HAS DRIFTED SOUTH OVER THE MIDDLE AND UPPER KEYS AND FLORIDA BAY THE PAST COUPLE OF HOURS...AS A RESULT OF AFTERNOON TCU TOPS OVER THE MAINLAND HAVING SPREAD OUT AT THE INVERSION LAYER. C-MAN SITE WINDS ALONG THE REEF ARE STILL E FOR THE UPPER AND MIDDLE KEYS...NE OF THE LOWER KEYS. THE USF PLATFORM IN NW FLORIDA BAY IS NOW CALM. FIRST PERIOD FORECASTS... PUBLIC ZONES WERE UPDATED AT 830 PM TO ACCOUNT FOR THE STRATOCU CLOUD COVER DESCRIBED ABOVE. ZONES INDICATED THAT THESE CLOUDS SHOULD GO AWAY AFTER MIDNIGHT TONIGHT. THE AIR IS QUITE DRY JUST ABOVE 6500 FEET. HOWEVER...THE 18Z RUC 850 MB R.H. PROGS MAINTAIN THIS MOISTURE MAXIMUM OVER THE UPPER AND MIDDLE KEYS WELL PAST MIDNIGHT. SO...THE CLOUDS MAY STUBBORNLY HANG ON FOR A WHILE AFTER MIDNIGHT. THE RUC AND MESO-ETA STILL INDICATE A TURNING OF SURFACE WINDS TO NE OVER THE MID AND UPPER KEYS AND FLORIDA BAY LATER TONIGHT. THUS...NO SIGNIFICANT CHANGES WILL BE MADE TO 1030 PM COASTAL MARINE ISSUANCE. .EYW...NONE. CLB fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 843 PM CST TUE MAR 21 2000 FCST ONLY NEEDS MINOR CHGS OVNGT AND MAINLY IN SWRN SXNS. TEMPS APCHG GOING MINS THERE SO HAD TO LOWER A CATEGORY OR SO. STILL XPC SOME FOG IN THOSE LOCATIONS SPCLLY THRU NISHNABOTNA VLY. THIS WL PROBABLY NOT LAST LONG HWVR AS STLT IMAGERY SHOWS INCRG MID CLDS AND IS SUPPORTED BY 00Z RUC WHICH GOES OVERCAST AFT MIDNIGHT. STILL SOME RADIATIONAL COOLING POTENTIAL FOR A FEW HRS SO WL KEEP MENTION OF FOG DVLPG WITH LGT ELY WNDS AND TEMP/DWPNT SPREADS STARTING TO GET UNDER 5 DEGREES AN INTERESTING SIDE NOTE...AP FM BIRDS HAS DVLPD IN SWRN PTNS OF RADAR UMBRELLA WHERE SKIES WHERE MSTLY CLR. WSR-88D VAD WNDS BECAME SLY 20-30KTS AFT 01Z. APPARENTLY BIRDS DO NOT LIKE FLYING OVR LOW CLDS. .DSM...NONE SMALL ia AREA FORECAST DISCUSSION...UPDATED FOR FOG NATIONAL WEATHER SERVICE NEW ORLEANS LA 950 PM CST TUE MAR 21 2000 AREAS OF GROUND FOG HAVE DEVELOPED AT THE SLIDELL AIRPORT...AND KPQL ALSO REPORTS FOG WITH VISIBILITIES AROUND ONE MILE. MAXIMUM RADIATION HAS COOLED TEMPERATURES DOWN TO NEAR THE DEWPOINTS FROM ST TAMMANY PARISH TO THE MS COASTAL COUNTIES. WILL UPDATE ZONES TO INCLUDE MENTION OF PATCHY FOG TONIGHT IN THIS AREA AND LOWER LOW TEMPERATURES TO 50 TO 55. PREVIOUS 915 PM DISCUSSION MID/UPPER RIDGE AND 850 MB HIGH JUST E OF FORECAST AREA HAVE KEPT THE CENTRAL GULF COAST REGION HIGH AND DRY TODAY WHILE ADJOINING AREAS TO THE NW RECEIVE NEEDED RAINFALL. THE MODELS STILL HAVE A PROBLEM GENERATING THE CONVECTIVE RAINFALL OVER N/CENTRAL LA WHERE 850 MOISTURE CONVERGENCE AND UPPER DIVERGENCE WITH A 80 KT 250 MB JET MAX ARE COINCIDENT. CONVECTION SHOULD CONTINUE TO REMAIN N OF THE SUBTROPICAL JET AXIS WHICH RUNS FROM EXTREME S TX TO SW MS TO S GA. ISENTROPIC LIFT AND STRONG WARM AIR ADVECTION OVER SURFACE STATIONARY FRONT EXTENDING FROM NEAR KLCH TO KMCB ALONG WITH LOW LEVEL JET/MOISTURE AXIS FROM SE TX/EXTREME SW LA TO E CENTRAL OK ARE ALSO AIDING THE PRECIP DEVELOPMENT. LONG WATER VAPOR LOOPS OVERLAYED WITH RUC ANALYZED VORTICITY SHOW WELL DEFINED SHORTWAVE TROUGH BECOMING BETTER DEFINED AS IT MOVED FROM CENTRAL MEXICO TO E TX THE LAST 24 HOURS. ANOTHER SHORTWAVE TROUGH AND ASSOCIATED UPPER JET STREAK HAVE MOVED INTO CENTRAL MEXICO LATE THIS AFTERNOON AND EVENING... AND THIS FEATURE SHOULD TRACK NE...PERHAPS A BIT FARTHER N THAN ITS PREDECESSOR. ALL IN ALL...LOOKS LIKE A DRY AND WARMER WEATHER REGIME SHOULD HOLD FOR THE NEXT SEVERAL DAYS. ONLY FORECAST CHANGE TO CONSIDER IS LOWS TONIGHT. FOR A CHANGE...PRESENCE OF HIGHER DEWPOINTS IN S ZONES AND CLOUDS IN N ZONES SHOULD KEEP LOWS AT OR PERHAPS A COUPLE DEGREES ABOVE THE FWC GUIDANCE. WILL HOLD OFF ON UPDATE FOR NOW. .NEW...NONE LA...NONE MS...NONE. 22 la AREA FORECAST DISCUSSION...UPDATED...CORRECTION NATIONAL WEATHER SERVICE NEW ORLEANS LA 915 PM CST TUE MAR 21 2000 MID/UPPER RIDGE AND 850 MB HIGH JUST E OF FORECAST AREA HAVE KEPT THE CENTRAL GULF COAST REGION HIGH AND DRY TODAY WHILE ADJOINING AREAS TO THE NW RECEIVE NEEDED RAINFALL. THE MODELS STILL HAVE A PROBLEM GENERATING THE CONVECTIVE RAINFALL OVER N/CENTRAL LA WHERE 850 MOISTURE CONVERGENCE AND UPPER DIVERGENCE WITH A 80 KT 250 MB JET MAX ARE COINCIDENT. CONVECTION SHOULD CONTINUE TO REMAIN N OF THE SUBTROPICAL JET AXIS WHICH RUNS FROM EXTREME S TX TO SW MS TO S GA. ISENTROPIC LIFT AND STRONG WARM AIR ADVECTION OVER SURFACE STATIONARY FRONT EXTENDING FROM NEAR KLCH TO KMCB ALONG WITH LOW LEVEL JET/MOISTURE AXIS FROM SE TX/EXTREME SW LA TO E CENTRAL OK ARE ALSO AIDING THE PRECIP DEVELOPMENT. LONG WATER VAPOR LOOPS OVERLAYED WITH RUC ANALYZED VORTICITY SHOW WELL DEFINED SHORTWAVE TROUGH BECOMING BETTER DEFINED AS IT MOVED FROM CENTRAL MEXICO TO E TX THE LAST 24 HOURS. ANOTHER SHORTWAVE TROUGH AND ASSOCIATED UPPER JET STREAK HAVE MOVED INTO CENTRAL MEXICO LATE THIS AFTERNOON AND EVENING... AND THIS FEATURE SHOULD TRACK NE...PERHAPS A BIT FARTHER N THAN ITS PREDECESSOR. ALL IN ALL...LOOKS LIKE A DRY AND WARMER WEATHER REGIME SHOULD HOLD FOR THE NEXT SEVERAL DAYS. ONLY FORECAST CHANGE TO CONSIDER IS LOWS TONIGHT. FOR A CHANGE...PRESENCE OF HIGHER DEWPOINTS IN S ZONES AND CLOUDS IN N ZONES SHOULD KEEP LOWS AT OR PERHAPS A COUPLE DEGREES ABOVE THE FWC GUIDANCE. WILL HOLD OFF ON UPDATE FOR NOW. .NEW...NONE LA...NONE MS...NONE. 22 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 900 PM CST TUE MAR 21 2000 LARGE AREA OF SHOWERS AND THUNDERSTORMS SHIFTING VERY SLOWLY NORTHEAST WITH WIDELY SCATTERED REDEVELOPMENT TO THE SOUTH. WILL NEED TO MENTION POPS FOR ENTIRE NIGHT...RATHER THAN JUST EVENING. RUC VORT SHOULD FINALLY CLEAR AREA BY DAYBREAK. IN THE MEANTIME... DEEP LAYERED BOUNDARY INDICATED ON RADAR VELOCITY MODE SHOULD BE SLOW MOVING AND MAY ALSO ACCOUNT FOR LOCALIZED VERY HEAVY RAIN IN MANSFIELD AREA. SHOULD STORMS REGAIN STRONG INTENSITIES...HAIL LIKELY ONLY SEVERE WEATHER THREAT. HIGH PRESSURE BUILDING TOWARDS AREA FROM NORTHEAST IMPACTING LOW NEAR BIG BEND AREA SHOULD KEEP ISOBARS SQUEEZED OVER MAINLY EAST TX...MAINTAINING SOUTHEAST WINDS TONIGHT AND THUS GULF MOISTURE FEED. WILL ADJUST ZONE POPS FOR RAIN TRENDS AND TEMPERATURES TO ACCOUNT FOR TEMPERATURE INCREASES WITH WARM FRONT MOVING INTO EAST TX. APPEARS PCPN TAPERS OFF BEHIND FRONT. VII .SHV...NONE. VII la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 254 PM CST TUE MAR 21 2000 AVN MODEL IS THE WAY TO GO AS IT HAS VERIFIED BEST EASILY WITH ITS 18Z SHORT WAVE POSITION WITH RESPECT TO CURRENT TSTM COMPLEX ADVANCING NORTHEAST FROM SOUTHEAST TX. HIGH POPS AND MENTION OF HEAVY RAIN BE NEEDED AT LEAST THIS EVENING IN PATH OF THIS SYSTEM. QUESTION IS...HOW FAR TO THE NORTH AND EAST BEFORE BREAKING UP? RUC MAINTAINS HIGHER MOISTURE CONVERGENCE AND INSTABILITIES ACROSS EAST TX. HOWEVER...IT GRADUALLY INCREASES 850 DEWPOINTS ACROSS REMAINDER OF AREA...THUS LEAVE IN POPS BUT DOWNPLAY THIS EVENING. AVN BRINGS MOISTURE ACROSS SLOWLY NORTHEAST TONIGHT...BUT WILL STILL LOSE BOTH PVA AND DIURNAL ASSISTANCE. ANY ISOLATED SVR ACTIVITY LIMITED TO EXTREME SOUTHWEST PORIONS AND WILL NOT BE MENTIONED UNLESS TRENDS STRESSES OTHERWISE. WEDNESDAY LOOKS SIMILAR TO TODAY WITH MOISTURE IN PLACE. HOWEVER... SHORT WAVE WILL CURL MORE NORTHWARD AS RIDGE BUILDS NORTHWARD IN GULF. THIS WILL TIGHTEN ACTIVITY MORE ACROSS TX/OK PORTIONS. AS UPPER LOW KICKS NORTHEAST ON THURSDAY...PATTERN TAKES ON MORE OF A SQUALL LINE APPEARANCE AT LEAST NORTH PORTIONS CLOSER TO THE LOW. INSTABILITIES A LITTLE LESS THAN TODAY/WED BUT WILL DEPEND ON ANY DAYTIME HEATING WITH MOISTURE LULL EARLIER IN DAY. FAN/FWC GUIDANCE SEEMS TO COME INTO MORE AGREEMENT WITH THIS FEATURE. GUIDANCE TEMPS IN GOOD AGREEMENT EXCEPT FOR ANOMALOUS DIFFERENCE ON WED HIGHS. WILL GO WITH PERSISTENCE FROM TODAY EXCEPT ADJUST UPWARD TO THE EAST AND DOWNWARD TO THE WEST. RAISE A LITTLE ON THURSDAY AS WINDS BECOME MORE SOUTHERLY AND POSSIBLY LESS CLOUDS FOR AWHILE AFTER LIFTING OF MORNING LOW CLOUDS. ABSENCE OF WIND SHIFT AND COLD AIR INTRUSION MAKING FOR FAIRLY PERSISTENT AND WARM FORECAST ON EXTENDED. SHV 56/68/59/75 5425 TYR 61/70/64/77 4543 MLU 53/70/58/74 5223 LFK 63/71/64/77 4543 TXK 52/68/58/73 4326 .SHV...NONE. VII la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 840 PM EST TUE MAR 21 2000 KLWX RADAR CONTINUES TO SHOW RAIN OVER NORTHERN AND EASTERN MD.. BRIGHT-BANDING ON 88-D MAKES IT DIFFICULT TO DETERMINE INTENSITY.. BUT RETURNS FROM KDOX/KCCX RADAR INDICATE THAT PRECIP STARTING A SLOW WEAKENING TREND. HEAVIER PRECIP SHOWING UP ON KDOX/KDIX RADAR FOR THE EASTERN SHORE AND UP INTO NJ AND SRN PA. WV LOOP AND 00Z RUC ANALYSIS SHOWING UPPER LEVEL LOW FINALLY STARTING A SLOW MOVEMENT TO THE SE... CURRENTLY OVER CENTRAL VA. 00Z RUC SHOWS THIS LOW CONTINUING A MOVEMENT TOWARD THE TIDEWATER OVERNIGHT... AND THIS SHOULD KEEP THE HEAVIEST PRECIP OFF TO OUR EAST. SOME OF THE SMALLER CREEKS ACROSS NRN MARYLAND WERE APPROACHING THEIR BANKS LATE IN THE AFTERNOON... BUT LATEST REPORTS INDICATE THAT THEY ARE RECEDING. PRECIP OVERNIGHT SHOULD BE STEADY AND COMPARABLY LIGHT.. SO PLAN TO TAKE DOWN THE FLOOD WATCH WITH EVENING UPDATE. SNOW/ICE IN THE HIGHER ELEVATIONS RESULTED IN SOME ACCUMULATIONS.. SEE PNSWBC FOR AMOUNTS. PRECIP HAS TAPERED OFF FOR THE MOST PART OUT WEST.. THOUGH MODELS STILL INDICATE SOME WEAK WAA AND THREAT FOR SOME VERY LIGHT PRECIP WILL REMAIN OVERNIGHT. 00Z IAD SOUNDING HAS A LAYER OF COLD AIR ALOFT.. AND WILL HAVE TO MENTION SOME FLURRIES FOR THE HIGHER ELEVATIONS. HAVE BROKEN OUT A GROUP FOR HGR AND FDK... WHERE HIGHER ELEVATIONS IN THOSE COUNTIES MAY ALSO SEE SOME SNOW MIX IN WITH THE RAIN GOING THROUGH THE AREA OVERNIGHT. LITTLE/NO ACCUMULATION EXPECTED FOR THE REST OF THE NIGHT SO ADVISORY WILL BE DISCONTINUED WITH EVENING UPDATE. WILL DOWNPLAY POPS FOR THE REST OF THE CWA OVERNIGHT.. AS DEEPER MOISTURE WILL REMAIN CONFINED TO THE EAST OF US. TEMPS IN GOING FORECAST LOOK PRETTY GOOD.. AND ONLY SOME MINOR CHANGES PLANNED THERE. .LWX...SMALL CRAFT ADVISORY FOR TIDAL POTOMAC AND MD PORTION OF CHESAPEAKE BAY. MARGRAF! md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1120 PM EST TUE MAR 21 2000 MAIN PROBLEM ON UPDATE IS EXTENT OF FOG OVR FA AND STATUS OF DENSE FOG ADVISORY OVR DELTA-SCHOOLCRAFT GRPS. WV LOOP REVEALS SHRTWV MOVG INTO WRN ONTARIO WITH ASSOC WKNG SFC TROF OVR WRN ONTARIO/NRN MN. SOME TIGHTENING OF SW GRAD NOTED AHD OF SFC TROF IN RESPONSE TO INCOMING SHRTWV. BEST QG FORCING WL REMAIN WELL NORTH OF LAKE SUPERIOR AS SHRTWV SWEEPS ACROSS SRN ONTARIO AND LAKE SUPERIOR OVRNGT. GIVEN SHALLOW MOISTURE TO 800 MB INDICATED ON 00Z GRB SNDG...EXPECT LTL MORE THAN SCT SPRINKLES/DRIZZLE AS PER GOING FCST. MAIN EFFECT OF SHRTWV WL BE FLATTENING OF SFC RDG OVR MIDWEST AND SLIGHT TIGHTENING OF SW GRAD AS TROF APPROACHES AROUND 12Z...PER LATEST RUC AND ETA MODELS. BNDRY LYR MIXING WITH APPROACHING TROF SHOULD PREVENT FOG FM BCMG DENSE OR WIDESPREAD IN MOST AREAS. THE EXCEPTION WL BE IN DELTA-SCHOOLCRAFT WHERE MOIST SLY FLOW OFF COOLER LAKE MI WATERS HAS RESULTED IN DENSE FOG THERE...THUS WL KEEP CURRENT ADVISORY GOING INTO WED MORNING. SW UPSLOPE WND ALSO RESULTING IN SOME PATCHY DENSE FOG IN THE HIGHER TERRAIN OF MQT COUNTY. GENLY THOUGH...INCREASED BDNRY LYR WND AND DWNSLPG SW FLOW OVR WRN COUNTIES SHOULD LIMIT WIDESPREAD FOG OVRNGT. MIN TEMPS FM PREV FCST REASONABLE BASED ON CURRENT DWPNTS AND EXPECTED CLD CVR...SO LTL IF ANY CHANGES MADE. .MQT...DENSE FOG ADVY OVRNGT-EARLY WED MIZ013-014. VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 925 PM EST TUE MAR 21 2000 THE LATEST SURFACE REPORTS AND IR STLT DATA SHOWS NORTHERN LOWER AND EAST UPPER MICHIGAN UNDER MOSTLY CLOUDY TO CLOUDY SKIES... WITH A FEW POCKETS OF FOG BEGINNING TO BUILD INTO PORTIONS OF EAST UPPER MICHIGAN. MQT 88D SHOWING SOME ENHANCED RETURNS...POSSIBLY A FEW LIGHT RAIN SHOWERS...MOVING NORTHEASTWARD AWAY FROM MUNISING. THIS PRECIPITATION IS DUE TO A WEAK VORT MAX MOVING QUICKLY OVER SOUTHERN LAKE SUPERIOR WITH ABUNDANT LOW LEVEL MOISTURE IN PLACE. THE LATEST RUC SHOWS THIS 500 MB FEATURE TO MOVE NORTHEAST... NORTH OF WHITEFISH POINT THIS EVENING. THIS WILL ALLOW THE CURRENT AREA OF PRECIPITATION NEAR MUNISING TO CONTINUE MOVING NORTHEAST AWAY FROM EAST UPPER MICHIGAN. THE MAIN TROUGH AT 500 MB...WILL MOVE EASTWARD TOWARD WESTERN LAKE SUPERIOR OVERNIGHT FORCING A VORT LOBE INTO EAST UPPER BY 12Z WED. PLENTY OF LOW LEVEL MOISTURE WILL LINGER OVER THE ENTIRE FORECAST AREA OVERNIGHT INCLUDING EAST UPPER MICHIGAN. THEREFORE WILL KEEP THE AREAS OF DENSE FOG AND A CHANCE OF RAIN SHOWERS OVERNIGHT FOR EAST UPPER. FOR NORTHERN LOWER MICHIGAN...HIGH PRESSURE RIDGING WILL REMAIN OVER THE REGION INTO WEDNESDAY MORNING. A DRY EAST/SOUTHEAST FLOW WILL CONTINUE OVER NORTHEAST LOWER OVERNIGHT LIMITING THE FOG AND LOW CLOUDS. HOWEVER A SOUTH TO SOUTHWEST FLOW DEVELOPS OVER THE WESTERN GREAT LAKES OVERNIGHT...WHICH WILL HELP BRING SOME FOGGY CONDITIONS TO NORTHWEST LOWER OVERNIGHT. CURRENT SURFACE OBSERVATIONS FROM EAST WISCONSIN ALREADY SHOWING VISIBILITIES 2 TO 3 MILES IN FOG ACROSS MUCH OF EAST WISCONSIN. UPDATES THIS EVENING WILL BE TO REWORD FIRST PERIOD FORECAST FOR ALL OF NORTHERN LOWER AND EAST UPPER MICHIGAN. .APX...NONE. SWR mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 830 PM CST TUE MAR 21 2000 A FEW SHOWERS REMAIN ALONG NRN PORTION OF FORECAST AREA... ASSOCIATED WITH WEAK ISENTROPIC LIFT AHEAD OF SHORT WAVE TROUGH... NOW IN CENTRAL MN. LATEST RUC MODEL INDICATES THIS LIFT STRETCHES EWARD...HOWEVER NEW AREA OF LIFT DEVELOPS OVER SRN MN AHEAD OF DEVELOPING SHORT WAVE TROUGH...NOW IN WRN SD. 00Z ETA MODEL SUPPORTS THIS DEVELOPMENT...ALTHOUGH A BIT FURTHER SOUTH AND A BIT SLOWER. MODELS ALSO DEVELOP SOME UPPER DIVERGENCE WITH LEFT EXIT OF UPPER JET ASSOCIATED WITH SHORT WAVE...AS WELL AS FAIRLY STRONG LOW LEVEL Q-DIVERGENCE. FORECAST WILL MENTION SHOWERS LATE TONIGHT IN SRN ZONES...AND CONTINUE SPRINKLES IN CENTRAL ZONES. .MSP...NONE. SCOTT mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 920 PM EST TUE MAR 21 2000 ONSHR PRES GRAD FM ERN NEW ENG CST AGAIN THIS EVNG...BUT SOME VARIATIONS ON THE BLOCKING THEME WITH SFC RDG POSITION SHIFTED CLOSER TO NH BDR ALG CT VLY AND BEST 3 HR SFC PRES RISES INVOF KGFL...SOMEWHAT SW OF POSITION 24 HRS AGO. KDIX RADAR SHOWS ATLC MSTR FEEDING ARND UPR LOW FM DE BAY RGN BRINGING RA INTO KHZL-KRDG- KLNS AREAS WITH MINIMAL RETURNS PAINTED AS FAR NE AS KMSV-KSWF TO THE E OF SFC PRES WKNS. MARINE LYR ON 00Z SOUNDING FM KOKX NOT CHGD THAT MUCH OVR 24 HRS...HOWEVER MARINE LYR ON KCHH SOUNDING BECAME VERY SHLW...ONLY ABT 1 HND FT DP WITH INVRSN BASED ARND 17 HND FT. RUC KEEPS PCPN ABT STNRY ACRS DE/ERN PA/SRN NJ WHILE H5 LOW IS PROGGED ACRS NRN VA AND SFC PRES GRAD DCRS ONLY MARGINALLY. BELIEVE WKNS IN SFC PRES FIELD MAY BE FAR ENOUGH TO THE W TO EXCLUDE PCPN FM SCHOHARIE VLY-TACONICS AND BRKSHRS AND ISOLD SPRNKLS MAY BE THE WORST EXTENT FOR ULSTER/DUTCHESS/LITCHFIELD COS. WL ALSO ADJUST ADRNDCKS FOR OCNL BKN CI AND WL REVISE TEMPS DOWN A NOTCH THERE. MCKINLEY .ALY...NY ERN/VT EXTRM SRN/MA EXTRM WRN/CT NW...NONE. ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1005 AM EST TUE MAR 21 2000 SFC LOW CENTERED NEAR CLKN7. LOW HAS MOVED LITTLE IN THE PAST SEVERAL HOURS. LATEST RUC MODEL INDICATING ONLY A SLOW DRIFT TO THE NORTH INTO THE AFTN HOURS. LOW CLOUDS AND FOG IN NO HURRY TO BREAKOUT ACROSS THE REGION. THIS SEEN WELL IN 12Z MHX RAOB WITH ALL THE LOW LEVEL MOISTURE EVIDENT. WITH PRESENT SCENARIO...BELIEVE CLOUDS WILL BE SLOW TO LIFT OVER THE AREA. ONLY BREAKS IN CLOUDS CURRENTLY SEEN OVER WESTERN NC. LOOKS AS THOUGH IF WE SEE ANY BREAKS IN CLOUD COVER OVER SE NC DUE TO SFC LOW MOVING NORTH...CLOUDS WILL FILL BACK IN WITH COOL MOIST NE FLOW AS IS SEEN FURTHER INLAND. A CLOUDY/MOSTLY CLOUDY WORDING WILL COVER THINGS BEST. WITH LESS SUNSHINE...TEMPS WILL LIKELY NOT REACH CURRENT FCST NUMBERS AND WILL HAVE TO LOWER MAX TEMPS A BIT MOST AREAS. WILL MONITOR LATEST OBS AND ADJUST AS NEEDED. CWF...WINDS SLOWLY COMING AROUND TO NW THIS MORNING AND SEAS BEGINNING TO SUBSIDE AT THE BUOYS. SEAS STILL UP ENOUGH NORTH PORTION TO WARRANT A CONTINUATION OF THE SCA FOR SEAS. SOUTHERNMOST LEG...MURRELLS INLET SOUTH...HAS HAD SEAS DROP TO 5 FT AND CAN EXCLUDE THAT PORTION FROM SCA. .ILM...SCA SURF CITY NC TO MURRELLS INLET SC. PJN nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH, NC 1002 AM EST TUE MAR 21 2000 COOL...MOIST NORTHEAST FLOW CONTINUES TODAY RESULTING IN LOTS OF CLOUDS. PRECIP HAS BEEN CONFINED TO NORTHEAST NCAROLINA AND EASTERN VIRGINIA WHERE BEST DYNAMICS. LATEST SURFACE ANALYSIS SHOW LOW PRESSURE NEAR STUMPY POINT. BOTH 06Z MESO-ETA AND 14Z RUC TOO FAR SOUTH. SO FOR LATE MORNING UPDATE...CONTINUE CLOUDY SKIES AND COOL TEMPERATURES. THICKNESS GIVES GREENSBORO HIGH OF 47. PATCHY DRIZZLE STILL AROUND BUT SHOULD BE GONE BY PRESS TIME. CURRENT TEMPERATURE FORECAST LOOKS REASONABLE....50S FOR CWA. ON PRECIP SEE MUCH SUPPORT EXCEPT A SMALL CHANCE POSSIBLE NORTHEAST ZONES. WILL TAKE A LOOK FOR NEW RUN AND 11 AM OBSERVATIONS. .RAH...NONE. RA nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 959 AM EST TUE MAR 21 2000 ...LOW CLOUDS TO TEMPER MAX TEMPERATURES TODAY... SPRING TIME UPPER LOWS ALWAYS PROVE DIFFICULT TO MODEL AND THIS SYSTEM NO EXCEPTION. YSTDY WE STRUGGLED WITH POPS/QPF. TODAYS CHALLENGE IS DETERMINING IF...OR WHEN...THE LOW CLOUDS WILL ERODE AS THIS OBVIOUSLY WILL HAVE A SIGNIFICANT EFFECT ON MAXIMUM TEMPERATURES. SATELLITE TRENDS ARE NOT ENCOURAGING AS A RATHER EXTENSIVE CANOPY OF LOW CIGS/BR COVERS MUCH OF NC AND NOW IS ADVECTING INTO SRN SC. THERE IS LOTS OF DRY AIR MOVG INTO ESTRN NC AS EVIDENCED BY DECREASING MODEL MEAN RH'S ACROSS THE REGION. THIS IS BEING TEMPERED BY DEEP MOISTURE THROUGH 700 MB AND CYCLONIC FLOW AS THE SFC LOW IS FCST TO REMAIN ACROSS COASTAL NC THROUGHOUT THE DAY. BASED ON THESE OBSERVATIONS AND AFTER COORDINATION WITH ILM...I WILL TREND TWRD A CLOUDY/MSTLY CLOUDY FCST WITH HIGHS IN THE MID 60S. ANY SUNSHINE WILL SEND TEMPERATURES INTO THE 70S. TODAYS PCPN FCST NOT AS TOUGH AS RUC/MESO-ETA AGREE ON SFC LOW PLACEMENT AND QPF FIELDS. BEST CHC WILL EXTEND FROM THE ALBEMARLE SOUND REGION INTO THE OUTER BANKS. REMAINDER OF ESTRN NC WILL HAVE LITTLE IN THE WAY OF PCPN EXCEPT FOR SOME PATCHY -DZ FROM THE LOW CLOUD DECK. PRES PATTERN FROM MSAS IN LINE WITH RUC/MESO ETA SFC FCSTS WHICH WILL MEAN GENERALLY LGT WINDS ACROSS MUCH OF THE WATERS THIS AFTERNOON. STILL GETTING A LARGE SWELL FROM MID-ATLC LOW WITH PERIODS AROUND 13 SECONDS. SCA WILL BE CONTINUED FOR THIS WITH A INCREASE IN WINDS LATE TONIGHT AND WED AS SFC LOW DRIFTS SE IN RESPONSE TO UPPER LOW MOVG INTO NC ON WED. HVY SURF ADVY'S WILL BE CONTINUED FOR MINOR OVERWASH EXPECTED ON THIS EVENINGS HIGH TIDE ALONG THE NRN OUTER BANKS. .MHX...HEAVY SURF ADVISORY FROM OCRACOKE N TO CURRITUCK BEACH LIGHT. SCA CSTL WTRS. ELARDO nc EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 850 PM CST TUE MAR 21 2000 DEEP SOUTHERLY FLOW TO CONTINUE WITH 18Z ETA AND THIS EVE'S RUC/NGM SHOWING VERY MOIST AIRMASS ABOVE 850 MB WITH SOME ELEVATED INSTABILITY. PRECIP HAS SLOWLY BE SPREADING N AND E THIS EVE. DRY AIR IN LOW LEVELS IS GRADUALLY GIVING IN TO LIGHT PRECIP...BUT PROGRESS OF MEASURABLE RAINFALL TO THE E WILL CONTINUE TO BE SLOW OVERNIGHT. SHOWERS WILL LIKELY CONTINUE TO DEVELOP SW OF THE AREA AS SYSTEM IS BEGINNING TO INGEST PLUME OF SUB-TROPIC MOISTURE AS SEEN IN WATER VAPOR IMAGES. IT WON'T TAKE MUCH LIFT AT ALL TO GET PRECIP GOING AND NEW 00Z ETA SHOWS SIG LIFT OVER CENT OK BY MIDNIGHT WHICH WEAKENS AND SPREADS INTO E OK BY 12Z. WILL UPDATE ZONES TO RAISE POPS TO LIKELY OVER WESTERN 1/2 OF THE AREA AND WILL LEAVE CHC POPS ELSEWHERE. TMPS LOOK OK. ETA SHOWING PRECIP MAINLY IN THE MORNING ON WED...SO WON'T FIDDLE WITH CHC POPS IN 2ND PERIOD. /13 .TUL... AR...NONE. OK...NONE. ok CENTRAL PENNSYLVANIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 945 PM EST TUE MAR 21 2000 WILL KEEP THIS SHORT...SINCE IT/S LATE AND FORECAST PRETY MUCH ON TRACK. UPPER LEVEL LOW WILL CONTINUE TO SLOWLY SINK SOUTH AND EAST TONIGHT. GOOD CONVEYOR BELT OF MOISTURE FROM THE ATLANTIC NOW STARTING TO REPOSITION ITSELF FARTHER SOUTH AS ADVERTISED BY THE 18Z MM5 AND RUC. DEEP EAST FLOW THROUGH 700 MB WILL FOCUS OVER SOUTHERN TIER OF CWA...THEN SLOWLY SHIFT SOUTH OF THE STATE OVERNIGHT (AFTER 09Z) WILL CONTINUE FFWS FOR FAR SOUTHEASTERN COS. HAVE ALSO ISSUED A HANDFUL OF RIVER FLOOD WARNINGS (SEE PHLFLWCTP). .CTP...FFW FOR YORK AND LANCASTER CO UNTIL 300 AM. FLW FOR SEVERAL TRIBUTARIES OF THE MAIN STEM SUSQ. JUNG pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 845 PM EST TUE MAR 21 2000 DEWPTS CURRENTLY RUNNING ABOVE GUID VALUES HOWEVER TEMPS ARE A BIT BELOW. WINDS ARE STILL RATHER VARIABLE BUT SHOULD BECOME N BY MORNING AND STAY UP SLIGHTLY OVERNIGHT. BASICALLY CLOUD FREE SKIES EXCEPT FOR THE SMALL PATCH OF OVC040 AT THE AIRPORT WHICH LOOKS TO BE BLOSSOMING ALONG THE COAST. EXPECT THIS AREA TO EVENTUALLY PUSH OFF THE COAST TONIGHT AND AT THIS TIME WILL GO WITH BECOMING MOSTLY CLEAR WORDING FOR SKIES IN THE COASTAL SC SECTION BUT WILL WAIT FOR MORE SATELLITE IMAGERY TO MAKE THE FINAL DECISION. OTHERWISE DRY AIR OVER THE AREA WITH CAA TO TAKE OVER TONIGHT. TEMP FCST LOOKS REASONABLE. ONLY MINOR TWEAKS EXPECTED TO CURRENT FCST. CWF...WINDS SLOWLY COMING UP AT 41004 AND FPSN7 AS BROAD LOW PRES E OF VA/NC TGHTNS PG ACRS RGN. WHILE MESOETA VERIFYING CLOSE TO OBSERVED CONDS AT 00Z...LUKS AS IF IT MAYBE A LTL OVRDONE WI SFC WNDS ACRS SRN CSTL WATERS...GA AND POINTS S. THERE IS SOME TGHTNG OF PG IN THS AREA...BUT WL NOT RESULT IN THE 20 TO 25 KT OF WIND BY DAYBRK FM SAV SWD FCSTD BY MESOETA. LATST RUC LUKS MORE REASNBL...WI BST PG OVR SC WATERS AND WINDS TO 15 TO 20 KT...WHILE GA WATERS CLOSER TO 15 KT BY DYBRK. WL UPDATE FOR INIT CONDS...OTRW RST OF FCST LUKS ON TRACK AND NOT PLANNING MUCH CHG UNLESS SOMETHING DRAMATIC HAPPENS BFR ISSUANCE. WL WAIT FOR 03Z BUOY OBS TO COME IN BEFORE SENDING OUT PKG. TKS FOR COORD JAX. .CHS... SC...NONE. GA...NONE. SLF/WOODWORTH sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1012 AM EST TUE MAR 21 2000 RUC AND 06Z ETA BOTH INDICATE THE LOW STRATUS SHOULD ERODE DURING THE AFTERNOON. BOTH HAVE WINDS BECOMING NWLY WITH DECREASING MOISTURE AT 925 AND 850 MB. THE EXCEPTION IS ACROSS THE NRN MTNS WHERE MOISTURE ACTUALLY INCREASES. WILL KEEP POPS IN NRN MTNS WITH INCREASING MOISTURE AND NWLY FLOW. WILL DROP ELSEWHERE GIVEN LACK OF FORCING AND CURRENT LOCATION OF PRECIP. BREAKS ARE OCCURRING ALONG THE ESCARPMENT. BIG QUESTION IS WHETHER THEY WILL INCREASE. OF COURSE THIS ALSO AFFECTS TEMPS. THICKNESSES COMBINED WITH LOW CLOUDS GIVE HIGHS LOWER THAN FORECAST. ONLY LOCATION TO HAVE RECEIVED FULL SUN TODAY HAS BEEN WRN MTN SECTIONS. EVEN IF CLOUDS DISSIPATE WARMING WILL HAVE BEEN RETARDED. WILL KEEP SOME LATE CLEARING WORDING AND WILL PROBABLY HAVE TO LOWER TEMPS IN MOST LOCATIONS. .GSP...NONE. RWH sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 850 PM CST TUE MAR 21 2000 LIGHT FOG AND LOW STRATUS LINGERING OVER FAR EASTERN COUNTIES... OTHERWISE SFC OBS INDICATE JUST MID CLOUDS COVERING CWA AT THIS HOUR. 00Z RUC STILL FORECASTING DECENT RH AT LOW LEVELS...AND WITH SURFACE DEWPOINTS IN MID TO UPPER 30S AND LIGHT WINDS...CANNOT RULE OUT REDEVELOPMENT OF SOME FOG...MOST LIKELY IN EASTERN SECTIONS WHERE LOW CLOUDS HAVE BEEN MOST PERSISTENT PAST FEW DAYS. RADAR RETURNS ON AREA MOSAIC HAVE BEEN DIMINISHING. 00Z RUC AND ETA HAVE WAVE TRIGGERING LIGHT SHOWERS ACTIVITY WEAKENING FURTHER OVERNIGHT. GOING FORECAST IN GOOD SHAPE. WILL SEND UPDATE TO REMOVE MENTION OF SPRINKLES/LIGHT SHOWERS...BUT NO OTHER CHANGES ANTICIPATED. .FSD...NONE HAMEN sd AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE FORT WORTH TX 920 PM CST TUE MAR 21 2000 RAIN AND THUNDERSTORMS HAS BEEN OCCURRING IN AN AREA OF ISENTROPIC LIFT NORTH OF THE WARM FRONT...WITH A CAPPING INVERSION ACTING AS A SOUTHERN BOUNDARY TO THE PRECIPITATION. PRECIP PROCESS IS LIKELY ENHANCED BY A SHORT WAVE TROUGH MOVING ACROSS THE NORTH TEXAS AREA... AS PER THE MESOSCALE MODELS. ALSO...THERE IS A SUB-TROPICAL JET MAX MOVING INTO SOUTH TEXAS...WITH THE LEFT EXIT REGION ACROSS SOUTH AND CENTRAL TEXAS. THE SOUTHERN BOUNDARY OF THE SHOWERS HAS MOVED NORTH SOMEWHAT THIS EVENING. MODELS SUGGEST THAT PRECIP WILL DIMINISH AS THE SHORT WAVE SUPPORT MOVES OUT...ALTHOUGH WARM ADVECTION TERM/LEFT EXIT REGION OF JET SHOULD KEEP SOME SHOWER ACTIVITY IN PLACE MUCH OF THE NIGHT AND POSSIBLY INTO WEDNESDAY. I WILL UPDATE THE ZONE FORECASTS AND RAISE POPS IN THE NORTH AND NORTHEAST...AND KEEP POPS HIGH IN CENTRAL AREAS...WHILE CALLING FOR SOME DIMINISHING OF HEAVIER PRECIP OVERNIGHT. THE RUC2 SUGGESTS THAT PRECIP WILL PICK UP IN WEST TEXAS OVERNIGHT...AND APPROACHING SHORT WAVE TROUGH WRAPPING AROUND THE LOW MAY IGNITE ADDITIONAL ACTIVITY IN THAT AREA. ONE HP SUPERCELL FORMED NW OF ABILENE...A FEW OTHER HAIL STORMS MAY OCCUR IN THE WEST WHERE VERTICAL SHEAR IS A BIT STRONGER THAN FURTHER EAST. WE WILL CAL FOR A FEW STORMS SEVERE IN THE WEST...WITH HAIL THE MAIN PROBLEM FROM THE ELEVATED STORM CELLS. THE NEW ETA FORECASTS THE UPPER SYSTEM TO MOVE ACROSS WITH A STRONG IMPACT THURSDAY. IN THE MEANTIME...WE WILL HAVE TO WATCH FOR SOME INCREASE IN A HEAVY RAIN THREAT AS THE GROUND BECOMES MORE SATURATED NORTH OF THE WARM FRONT. .FTW...NONE. 26 tx SOUTHEAST TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 905 PM CST TUE MAR 21 2000 KHGX AND SFC OBS INDICATE OCCASIONAL LIGHT RAIN/DRIZZLE GENERALLY ALONG AND NORTH OF I-10 THIS EVENING. OTHERWISE...HUMID AND MILD OVER SERN TX. THE MAIN UPDATE ISSUES ARE THE SEVERE THREAT... POPS...AND TEMPS. THE SHORTWAVE TROUGH/JET STREAK SEEN ON WV IMAGERY AND AIRCRAFT/ UPPER AIR OBS OVER NRN MX ARE NOT HANDLED PARTICULARLY WELL BY THE LATEST RUC RUNS AND JUST IN 00Z ETA. HOWEVER...SURROUNDING 00Z CRP/DRT/LCH/SHV/FWD RAOBS POINT TO GREATEST THREAT FOR THUNDERSTORMS AND SEVERE WEATHER NORTHWEST OF SERN TX...PER LATEST SPC SWODY1. THERE SEEMS TO BE A SUBSTANTIALLY INCREASING THREAT WED INTO THU AM. SIMILARLY...POPS MAY ALSO NEED INVERTING TO HIGHER VALUES IN LATER PERIODS. WILL REFRAIN FROM ANY LATER PERIOD CHANGES BUT MAKE THE FOLLOWING CHANGES FOR TONIGHT...REMOVAL OF SEVERE THREAT...POPS WORDING TO OCCASIONAL DRIZZLE THEN SCATTERED SHOWERS AND THUNDERSTORMS LATE WITH MEASURABLE RAIN POP. TEMPS ARE ALREADY WELL BELOW THE FORECAST MINS IN THE NRN 1/3 OF THE CWA BEHIND THE NOW SOUTH SAGGING WARM BOUNDARY. WILL HAVE TO ADJUST TEMPS DOWN 5-8F EXCEPT FOR THE SWRN ZONES AND ALONG THE COAST. WILL ALSO DIAL DOWN THE MARINE FORECAST ONE NOTCH TO SCEC FOR THE BAYS AND ALL OFFSHORE WATERS. THANKS FOR COORD LCH. .KHGX...SCEC BAYS AND GULF WATERS. 31/30/35 UPDATED PRELIMS... CLL TE 059/074 065/078 063 5523 IAH TE 062/076 066/078 066 5523 GLS EB 067/073 068/074 068 3423 SW EB 069/074 069/076 068 2423 NE EE 057/077 063/077 065 5423 tx SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 300 AM MST WED MAR 22 2000 ...MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES FOR TODAY... PESKY CUTOFF LOW IS CONTINUING TO SPIN OVER SOUTHERN ARIZONA. CURRENTLY ONLY CLOUDY SKIES OVER MUCH OF OUR CWA. A BAND OF PRECIPITATION OVER NORTHEAST NEW MEXICO IS VERY SLOWLY DRIFTING NORTH AND EAST. THIS BAND IS THE NORTHERN EXTENSION OF CONVECTION CURRENTLY OVER TEXAS. THE MOVEMENT OF THIS BAND IS THE MAIN FACTOR IN PRECIPITATION FOR TODAY. KPUX SUGGESTS MAYBE A FEW SNOW SHOWERS OVER THE EXTREME SOUTHERN SANGRE DE CRISTOS. THE NGM...AVN AND ETA HAVE A BAND OF HIGH 500-850MB RELATIVE HUMIDITY OVER THE SOUTHEAST PLAINS DURING THE AFTERNOON. THE MODELS HAVE SOME SIGNIFICANT PRECIPITATION INTO THE SOUTHEAST PLAINS WITH THE ETA HAVING A MAXIMUM OF AROUND 0.75 INCHES IN 12 HOURS. THERE ARE SOME MODEL DIFFERENCES WITH THE STRENGTH OF UPSLOPE ON THE PLAINS. DURING THE AFTERNOON THE RUC...AVN AND NGM HAVE 700 MB SPEEDS 20 TO 30 KNOTS WHILE THE ETA ONLY HAS WIND SPEEDS OF 10 KNOTS. LOOKING AT THE RADAR MOSAICS...THE WESTERN EDGE OF THE PRECIPITATION AREA OVER NORTHEAST NEW MEXICO IS WEAKENING AS IT DRIFTS NORTH. THE RADAR SHOWS BAND HAVING A TOUGH TIME MOVING NORTH. WITH THE CUTOFF CONTINUING TO MOVE EAST DURING THE NEXT 12 HOURS...I BELIEVE THE MODELS ARE MOVING THE LIFTING FIELD TOO FAR NORTH INTO COLORADO. I EXPECT ONLY WEAK UPSLOPE FLOW TODAY AND ONLY WEAK SYNOPTIC SCALE LIFT OVER THE REGION. AS A RESULT...WE WILL CANCEL THE WATCH FOR THE SOUTHEAST MOUNTAINS AND MENTION SUB ADVISORY ACCUMULATIONS FOR TODAY. THE LARGER PRECIPITATION EVENT MAY OCCUR OVERNIGHT AND INTO THURSDAY WITH THE DEFORMATION BAND NORTH OF THE CUTOFF AS IT LIFTS OVER TEXAS. AVN IS FURTHEST NORTH AND HAS SIGNIFICANT RH AND LIFT INTO SOUTHEAST COLORADO WHILE THE FURTHER SOUTH ETA SOLUTION HAS THE BAND JUST SOUTHEAST OF COLORADO. WITH 700 MB TEMPERATURES AROUND -1 TO -2 C...THIS EVENT CAN BE MOSTLY RAIN WITH SOME WET SNOW. WITH THE WARM TEMPERATURES...I DO NOT SEE ANY REASON AT ALL TO ISSUE ANY KIND OF WATCH OR HIGHLIGHT THE EVENT. IN THE EXTENDED...DRY FORECAST THROUGH SUNDAY LOOKS GOOD AS WE ARE AHEAD OF NEXT SYSTEM DIVING INTO CALIFORNIA. BY MONDAY THE MRF HAS THE STORM AFFECTING COLORADO. CURRENT MRF LOOKS NASTY...BUT THIS IS A LONG WAY OFF. .PUB...NONE. WOLYN co WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION. NATIONAL WEATHER SERVICE GRAND JUNCTION CO 250 AM MST WED MAR 22 2000 FORECAST ATTENTION REMAINS ON SOUTHERN-MOST ZONES AS AZ/MX CLOSED- LOW PREPARES TO EXIT. AT 06Z...ASSOCIATED HIGH-CLOUD SHIELD HAS SPREAD UP TO THE COLORADO RIVER VALLEY. SATELLITE SHOWS PROGRESSIVE NORTHERN BRANCH WITH SHEAR AXIS BEING STRETCHED FROM AZ LOW-NW CO- MINNESOTA. MORE PERTINENT TO SOUTHERN POPS FOR TODAY...VIGOROUS VORT LOBE SEEN ROTATING INTO BOTTOM OF LOW...GIVING IT A SHORT-TERM NEGATIVE TILT AND DEEPER ENHANCEMENT IN NORTHERN NM. JET ENERGY BECOMING MORE BALANCED AROUND THE AZ LOW. 06Z RUC AND AVN SHOW MORE OF A CYCLONIC CURVE TO EAST-SIDE JET WHICH WOULD EXPLAIN ENHANCED CLOUDS SPREADING BACK INTO SE UTAH. 700 OMEGA FIELD HAS NOT BEEN CORRELATED WELL WITH PRECIP IN THIS SCENARIO. DIVERGENCE HAS BEEN A BETTER PREDICTOR. A GOOD 700/300 CONV/DIV COUPLET ENHANCES OVER THE SOUTH THRU 18Z...THEN DIMINISHES. BASED ON THIS WILL KEEP POPS SOUTH OF A LINE FROM GUNNISON TO MONTICELLO TODAY. ALL MODELS SHOW LOW BEGINNING TO MOVE THIS MORNING WITH THE 700-500 LOW PASSING INTO SE NM TONIGHT. MODELS TRY TO WRAP A WEAK JET STREAK IN FROM THE EAST TONIGHT...BUT THIS DOWNSLOPE DIRECTION SEEMS UNLIKELY TO BE VERY PRODUCTIVE. THE MAIN PRECIP THREAT TO BE ALONG THE CONTINENTAL DIVIDE...MAINLY SOUTH. RIDGING THURSDAY. WEAK DISTURBANCE THURSDAY NIGHT IN THE AVN PRODUCES QPF ALONG WEST SLOPE...IS DISCOUNTED FOR NOW. IN THE NEW MRF AND OTHER SPECTRALS...THE KICKER IS NO LONGER PROGRESSIVE FRIDAY BUT BEGINS BLOCKING PATTERN WITH CLOSED LOW INTO AZ AGAIN BY SUNDAY WILL DIMINISH NORTHERN POPS FOR FRIDAY. OTHERWISE SATURDAY LOOKS WARM IN SW FLOW. 99/RAMEY .GJT...NONE. EMERGENCY MANAGERS IN SOUTHERN COLORADO AND SOUTHEAST UTAH SHOULD MAINTAIN A HEIGHTENED LEVEL OF WEATHER AWARENESS TODAY DUE TO CONTINUED VALLEY RAIN AND MOUNTAIN SNOW SHOWERS. OTHER EMERGENCY MANAGERS IN EASTERN UTAH AND WESTERN COLORADO SHOULD MAINTAIN A NORMAL LEVEL OF WEATHER AWARENESS TODAY. co NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 230 AM MST WED MAR 22 2000 SHORT TERM DISCUSSION...UPPER LOW IN AZ NOT EXPECTED TO MAKE MUCH MOVEMENT TODAY. MODELS INCLUDING 06Z RUC SHOW LOW INVOF TRI-POINT AREA OF AZ/NM/MEXICO BRDRS AT 18Z EXCEPT ETA WHICH IS 6 HRS SLOWER AND PUTS LOW THERE AROUND 06Z TNGT. THIS WILL KEEP DFLNT SLY FLOW OVER NERN CO TODAY. E-W ORIENTED RDG OVER THE AREA TO PRETTY MUCH SQUASH ANY PCPN THREAT UNTIL LATE AFTN WHEN THE RDG REACHES CO-WY BRDR AND START TO GET A LITTLE MORE INSTBY AND MSTR. WILL CUT THE POPS BACK TO ISOLD FOR PLAINS ZONES AS NO MECHANISM TO PROVIDE ANY LIFT UNTIL LATE AFTN. MAY GET SOME ORGRPHC LIFT OMTNS THUS WIDELY SCT SEEMS APPROPRIATE FOR ZONES 34...37...36 LATE TODAY WITH ISOLD REST OF MTN AND FTHL ZONES. WILL ALSO ADJUST MANY ZONES TO MOSTLY SUNNY FOR THIS MRNG WITH INCRSG CLDS IN AFTN. SOME HI LVL CLDS IN THE SRN PTN CWA ALREADY BUT SHUD BE THIN ENUF FOR PLENTY OF SUN TO SHINE THRU TIL MIDDAY WHEN THICKER SHIELD EXPECTED TO ARRIVE. SAT FOG PRODUCT SHOW LOW CLDS ARE BEING SWEPT E AND N AND NOW CONFINED TO LOGAN...SEDGWICK...PHILLIPS AND NE WASHINGTON COUNTIES AND MNLY MOVING NEWD WITH DRAINAGE WIND AUGMENTING WEAK S-SW FLOW. ANOTHER BAND OF LOW CLOUDS SIGHTED IN ERN LARIMER AND WELD COUNTY BUT THEY DO APPEAR TO BE MOVING N. WILL WAIT AND SEE WHAT SAT PIX SHOWS AT PRESS TIME BEFORE COMMITTING TO MRNG LOW CLDS IN ZONES. PRESENTLY LEANING TO MENTN ONLY IN ZONES 42-44...48 AND 50. LOW CLOUDS SHUD DISSIPATE BY 9 OR 10 AM. WITH SLY FLOW...FAIR AMT OF SUN AND SOME WAA EXPECT TEMPS TO CLIMB WELL ABOVE YESTERDAYS HIGHS WHICH AGREES WITH NUMERICAL GDNC. PREFER WARMER FAN OVER FWC FOR TODAYS TEMPS. BOODA LONG TERM DISCUSSION: MDLS RMN SIMILAR IN FCST TRACK OF THIS SLOW MOVING CLOSED LOW...MOVING IT INTO THE OKLAHOMA PANHANDLE BY 00Z FRI. NERN CO IS STUCK IN MORE OF A DEFORMATION AREA AS THIS STORM SYSTEM RMNS S AND E OF THE CWA. ETA TRIES TO DRY THE AMS OUT AFT 12Z THU WITH THE FCST SNDG VEERING WINDS ARND TO THE W. THE NGM AND AVN MAINTAIN A DEEP MSTR OVER CO TNGT AND MOST OF THU AS WNDS RMN ESELY THRU THE PD. BST POTENTIAL FOR SHOWERS WL RMN OVR SRN AND ERN PORTIONS OF THE CWA TGNT AND THU. ONLY FVBL FACTORS FOR SHOWERS WOULD APPEAR TO BE THE WEAK ESELY UPSLOPE THE MDLS GENERATE AND THE DEFORMATION ZONE THAT STICK OVR NERN CO. ON THE FLIP SIDE...THE QG FORCING APPEARS MINIMAL AND MID LVL INSTBY OVR NERN CO IS FAIRLY WEAK. SO FAR...THE MDLS HAVE CONSISTENTLY OVERDONE THE QPF FOR OUR CWA AND ARE PROBABLY DOING SO ATTM. AVN FINALLY SWINGS WNDS ARND TO THE NW FRI EVNG AS SYSTEM MOVES FURTHER E SO SHUD SEE SOME PARTIAL CLRG BY FRI AFTN...AT LEAST ACRS WRN SECTIONS OF THE CWA. AVN WEAKENS THE NEXT SYSTEM OFF THE PACIFIC NW COAST AS IT MAKES ITS WAY INLAND. AS A RESULT...BST CHC FOR ANY PCPN WITH THIS STORM FRI WL BE CONFINED TO THE MTNS. NEXT TROF SET TO DROP INTO THE GREAT BASIN AND CLOSE OFF SUNDAY INTO MON. SEE NO REASON TO MAKE ANY CHANGES TO THE EXTENDED ATTM. COOPER .DEN...NONE. co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 230 AM CST WED MAR 22 2000 HARD TO MISS LARGE POCKET OF CLEARING ACRS ERN 1/2 OF ILX CWA. MODELS (EVEN 06Z RUC) DID NOT PICK UP ON THIS. CLOUD TRENDS...AND THE EFFECT THIS HAS ON TEMPS...WILL BE THE FCST CHALLENGE AGAIN THIS RUN. WINCHESTER PROFILER DATA AT 925 MB SHOWING WEAK ERLY FLOW BECOMING MORE SERLY AFT 06Z. NICE WWRD PROGRESSION OF CLEARING SUBSEQUENTLY SLOWING UP CONSIDERABLY. CLEAR SKIES SHOULD START OUT DAY IN EAST... WITH CLOUDS MORE PREVALENT WEST. QUESTION IS HOW MUCH DIURNAL CU WILL FORM...IF ANY...AS HEATING AND ANY REMAINING LOW-LVL MOISTURE INTERACT IN CLEARING. THE BREAKS IN THE CLOUDS THAT FORMED IN INDIANA DURING DAY YESTERDAY FILLED BACK TO SCT-BKN LAYER CU. WITH THIS AIRMASS MOVING INTO ERN IL...WOULD EXPECT SAME TRENDS HERE. WL BE MORE PESSIMISTIC WEST WITH CLOUDY START. SPRING SUN SHOULD HELP BOOST TEMPS UP RAPIDLY. WL ADJUST TEMPS A BIT UPWARD. MODELS AGAIN IN FAIRLY GOOD AGREEMENT WITH MOVEMENT AND STRENGTH OF H5 CLOSED LOW OVR SRN AZ. AVN A BIT FARTHER WEST AND DEEPER...BUT DIFFERENCE NEGLIGIBLE TO ILX FCST ATTM. UPR RIDGE TO DOMINATE ACRS IL THRU 48 HRS AS LOW STARTS TO EJECT NEWRD THRU SRN PLAINS. SFC HIGH TO SLOWLY SHIFT EAST BY ERLY THU...ALLOWING SFC WINDS TO FINALLY PICK UP AND SHIFT SERLY. WL LIKELY SEE TEMPS BOOST UP NICELY THU...ALTHOUGH INCREASE IN MID-HIGH LVL CLOUDS MAY DAMPER WARM-UP SOMEWHAT. FAN/FWC GENERALLY IN GOOD AGREEMENT...BUT GIVEN BIZARRE CLOUD TRENDS TODAY WL NEED TO TWEEK A BIT. WL LEAN ON THE WARM-SIDE THU. NO CHANGES ANTICIPATED TO EXTENDED. ...PRELIMINARY CCF FOR COORDINATION ONLY... SPI EB 058/044 065/049 064 81000 PIA EB 057/043 064/048 063 81000 DEC BB 059/042 063/047 064 81000 CMI BB 060/041 063/046 064 81000 MTO BB 061/042 065/046 066 81000 LWV BB 063/042 066/046 067 81000 .ILX... IL...NONE. PLAHMER il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 440 AM EST WED MAR 22 2000 FORECAST FOR ERN UPR/NRN LWR OVER THE NEXT COUPLE OF DAYS REMAINS UNCHANGED FOR THE MOST PART...WITH PRIMARY QUESTION (AGAIN) BEING WHEN WILL CLOUDS WILL FINALLY START TO BREAK UP. CURRENT SURFACE ANALYSIS CONTINUES TO SHOW RATHER DISORGANIZED PATTERN ACROSS THE WESTERN GREAT LAKES REGION...WITH A WEAK RIDGE AXIS NUDGING THROUGH SRN LWR MI AND APPROACHING WEAK TROUGHS ACROSS THE NRN MS VLY AND NRN PLAINS REGIONS. ALOFT...LATEST WATER VAPOR IMAGERY SHOWS INITIAL NRN STREAM SHORTWAVE/SHEAR AXIS ACROSS THE MN ARROWHEAD REGION...WITH A MORE AMPLIFIED UPPER TROUGH ACROSS THE LAKE WINNIPEG REGION. 00Z RUNS INITIALIZED THESE UPPER FEATURES WELL... AND COMPARE FAVORABLY OVER THE NEXT 48 HOURS. TODAY...MODELS CONTINUE TO SHOW ENERGY FROM BOTH INITIAL (WEAKER) VORT LOBE AND MAIN UPPER TROUGH FIZZLING OUT AS THEY ENCOUNTER THE ZONAL/CONFLUENT FLOW ACROSS THE REGION. 850-500 MB Q-VECTOR CONVERGENCE IS MINIMAL AS A RESULT...WITH MODEL SOUNDINGS SHOWING LIMITED MOISTURE ABOVE 850 MB OR THE 0C ISOTHERM (ESPECIALLY ACROSS NRN LWR). THUS...EXPECT MORE ORGANIZED AREA OF LIGHT RAIN CURRENTLY ACROSS WESTERN UPPER MI TO DIMINISH AS IT CONTINUES TO HEAD EAST. WILL CARRY A CHANCE OF SPRINKLES THROUGH THE MORNING HOURS OVER THE NRN ZONES (ERN UPR MI) GIVEN THE SLIGHTLY BETTER FORCING AND MID LEVEL MOISTURE AVAILABILITY...WHICH AGAIN IS SUPPORTED BY LATEST SATELLITE (IR) AND RADAR TRENDS. TO THE SOUTH ACROSS NRN LWR MI... WILL MAINTAIN DRY WEATHER. CONTINUED WITH THE MOSTLY CLOUDY FCST IN ALL ZONES TODAY. IF ANYTHING...WEAK UPPER DIVERGENCE/SFC CONVERGENCE ASSOCIATED ON THE TAIL END OF THESE SHORTWAVES WILL LIKELY INHIBIT THE LARGE-SCALE SUBSIDENCE/DRYING NEEDED TO BREAK UP THESE LOWER CLOUDS (MUCH SIMILAR STORY TO YESTERDAY...WHERE LOW LEVEL Q-VECTORS WERE MORE CONVERGENT THAN OTHERWISE). ETA/NGM/AVN CONTINUE TO SHOW CONSIDERABLE 925-850 MB MOISTURE THROUGH THE DAY AS A RESULT (LAYER-AVERAGE RH ABOVE 80 PERCENT)...WHICH IS ALSO SUPPORTED BY LATEST (06Z) ETA AND RUC MODELS. CONSISTENT WITH PRIOR FORECAST PACKAGE...KEPT CONSIDERABLE CLOUDS IN TONIGHT ACROSS MOST LOCATIONS. FLOW DOES BECOME MORE ANTI-CYCLONIC LATE TONIGHT FOLLOWING THE SECONDARY SHORTWAVE...THOUGH WITHOUT THE EFFECTS OF DAYTIME MIXING SUSPECT LOWER CLOUDS WILL BECOME TRAPPED UNDER THE STRENGTHENING SUBSIDENCE INVERSION. WAS MORE OPTIMISTIC ACROSS ERN UPR (DECREASING CLOUDS) AS MODEL SOUNDINGS SHOW MORE DEFINITIVE DRY AIR ADVECTION BETWEEN 950-900 MB LATE TONIGHT OVER THIS REGION. RIDGING AT ALL LEVELS BECOMES MORE ESTABLISHED ON THU. MODEL SOUNDINGS SHOW MIXING THROUGH 850 MB...THOUGH ETA IS ONCE AGAIN DISPLAYING ITS TYPICAL MOIST BIAS NEAR SFC. STICKING WITH THE NGM SOUNDINGS...RELATIVE DRYNESS AT THE SFC/WARMTH AT 850 MB OR INVERSION BASE WILL LIMIT CU/SC COVERAGE...THUS HAVE CONTINUED WITH MOSTLY SUNNY FORECAST FROM PREVIOUS PACKAGE. 850 MB TEMPS RISING TO AROUND 2-3C WILL SUPPORT HIGHS NEAR 60 ACROSS NRN LWR...AGAIN CONSISTENT WITH PREVIOUS FORECAST. WILL ALSO KEEP COOLER TEMPS NEAR THE GREAT LAKES WITH THE LOW LEVEL RIDGE AXIS ACROSS THE REGION... AS LIGHT 950 MB WINDS (AT OR BELOW 10 KTS) SHOULD BE EASILY OVERCOME BY THE LAND-WATER TEMPERATURE CONTRAST (DELTA T'S OF 20-25F). NO CHANGES MADE TO THU NIGHT/FRI PORTION OF EXTENDED BASED ON LATEST AVN AND ETA/NGM EXTRAPOLATION. .APX...NONE. HURLEY mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 435 AM EST WED MAR 22 2000 MAIN FCST PROBLEMS THIS PACKAGE INCLUDE SCT LIGHT RAIN OR SPRINKLES THIS MORNING ALONG WITH CLOUD/FOG TRENDS AND TEMPS. WV LOOP INDICATED CONTINUED SPLIT FLOW PATTERN WITH CUTOFF LOWS OVER AZ/NM AND MID ATLANTIC WHILE FAST NRN STREAM FLOW EXTENDS FROM BC ACRS SRN CANADA TOWARD WRN GRT LAKES AND QUEBEC. ONE NRN STREAM VORT WAS MOVING THROUGH CNTRL MANITOBA. ANOTHER SHEARED OUT SHRTWV MOVING FROM ONTARIO AND NE MN WAS SUPPORTING A BAND OF LIGHT PCPN FROM WRN UPR MI INTO NW WI. IN ADDITION TO MODEST 700-300 QVECTOR CONVERGENCE WITH THE SHRTWV... LIFT WAS BOOSTED BY PRESENCE DIV WITH LFQ OF JET EMERGING FROM THE PLAINS...PER WIND PROFILERS AND 06Z RUC AND ETA. PRECIP INTENSITY WAS ENOUGH TO OVERCOME 800-600 DRY LYR ON FCST AND OBSERVED SNDGS. AT THE SFC...VSBY HAD IMPROVED AT MQT AND SAW BUT STILL LINGERED AROUND 1/4SM AT ESC AND ISQ. TODAY...06Z ETA FCST 700-300 QVECTOR CONVERGENCE AND EXTRAPOLATED MOVEMENT OF BAND FROM SATELLITE/RADAR SUGGESTS PCPN WILL MOVE THROUGH CNTRL CWA BY 12Z AND EAST BY 14Z. 06Z ETA ALSO SUGGESTS TAIL OF MANITOBA VORT MAY HELP KICK OFF A TRAILING BAND OF SPRINKLES OR LIGHT RAIN OVER KEWEENAW BTWN 12Z-15Z...EVEN THOUGH ONLY MID CLDS OBSERVED SO FAR WITH THIS FEATURE. DENSE FOG OVER PORTIONS OF SE WL LINGER TIL WINDS BECOME MORE WRLY AND DIURNAL WARMING KICKS IN. LIGHT PCPN THIS MORNING MAY ALSO HELP SCOUR OUT FOG. MOST PERSISTENT FOG EXPECTED ALONG LK MI SHORELINE WHERE WEAK SSW FLOW CONTINUES TO ADVECT AIR WITH LOW TO MID 40S DEWPOINTS TOWARD ACRS THE LAKE. BEST DNVA... QVECTOR DIV AND 850-500 DRYING FCST NORTH OF AREA AS MANITOBA SHRTWV MOVES TOWARD JAMES BAY. LINGERING 1000-850 MOISTURE MAY BE A BIT STUBBORN. HOWEVER...GRADUALLY VEERING FLOW WITH INCREASING DRY ADVECTION ALONG WITH DIURNAL HEATING SHOULD HELP BRING SOME CLEARING FROM WEST AND CNTRL. LINGERING SW FLOW OVER EAST WL KEEP CLOUDS IN A BIT LONGER. WARMEST TEMPS EXPECTED OVER WEST WITH MOST SUNSHINE. VALUES AOB GUIDANCE OVER EAST HLF WITH CLOUDS BREAKING UP LATER IN AFTERNOON OR EVENING. TONIGHT...DELAYED CLEARING DURING THE AFTERNOON SHOULD LEAVE CLOUDS OVER SOUTHEAST. WITH NIGHTFALL AND RELATIVELY WEAK WIND FIELD...ADDITIONAL CLEARING WILL BE DIFFICULT. WHERE CLEARING DOES OCCUR...EXPECT FOG TO REDEVELOP TONIGHT WITH GOOD RADIATIONAL COOLING AND LEFTOVER BNDRY LYR MOISTURE. THURSDAY...EXPECT MORNING FOG AND LOW CLOUDS TO BURN OFF WITH MORE SUNSHINE AIDED BY INCREASING MID LVL AND SFC RIDGING AHEAD OF SLOWLY EJECTING SW CUTOFF. RELATIVELY WEAK SRLY GRADIENT SHOULD ALLOW FORMATION OF LK BREEZES AND COOLER REGIME NEAR LK SUPERIOR. DEEPER MIXING AOA 850 MB WITH 850 TEMPS FCST AROUND 2C SHOULD ALLOW TEMPS TO CLIMB TO AT LEAST THE MID 50S INLAND. .MQT...DENSE FOG ADVY EARLY TODAY MIZ013-014. JLB mi NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 4 AM MST WED MAR 22 2000 ...UPDATE TO SHORT TERM DISCUSSION... HAVE CHANGED MIND ABOUT MOSTLY SUNNY FOR THIS MRNG. WILL GO WITH INCREASING CLOUDS SINCE LEAD EDGE OF HIGH CLOUDS ALREADY OVER CWA ACCORDING TO SAT LOOP AND APPEAR THICKER THAN EXPECTED. PRESENCE OF RDG OVER CWA SHUD KEEP AMS MSTLY STBL SO RIDING WITH LOW POPS. SHORT TERM DISCUSSION...UPPER LOW IN AZ NOT EXPECTED TO MAKE MUCH MOVEMENT TODAY. MODELS INCLUDING 06Z RUC SHOW LOW INVOF TRI-POINT AREA OF AZ/NM/MEXICO BRDRS AT 18Z EXCEPT ETA WHICH IS 6 HRS SLOWER AND PUTS LOW THERE AROUND 06Z TNGT. THIS WILL KEEP DFLNT SLY FLOW OVER NERN CO TODAY. E-W ORIENTED RDG OVER THE AREA TO PRETTY MUCH SQUASH ANY PCPN THREAT UNTIL LATE AFTN WHEN THE RDG REACHES CO-WY BRDR AND START TO GET A LITTLE MORE INSTBY AND MSTR. WILL CUT THE POPS BACK TO ISOLD FOR PLAINS ZONES AS NO MECHANISM TO PROVIDE ANY LIFT UNTIL LATE AFTN. MAY GET SOME ORGRPHC LIFT OMTNS THUS WIDELY SCT SEEMS APPROPRIATE FOR ZONES 34...37...36 LATE TODAY WITH ISOLD REST OF MTN AND FTHL ZONES. WILL ALSO ADJUST MANY ZONES TO MOSTLY SUNNY FOR THIS MRNG WITH INCRSG CLDS IN AFTN. SOME HI LVL CLDS IN THE SRN PTN CWA ALREADY BUT SHUD BE THIN ENUF FOR PLENTY OF SUN TO SHINE THRU TIL MIDDAY WHEN THICKER SHIELD EXPECTED TO ARRIVE. SAT FOG PRODUCT SHOW LOW CLDS ARE BEING SWEPT E AND N AND NOW CONFINED TO LOGAN...SEDGWICK...PHILLIPS AND NE WASHINGTON COUNTIES AND MNLY MOVING NEWD WITH DRAINAGE WIND AUGMENTING WEAK S-SW FLOW. ANOTHER BAND OF LOW CLOUDS SIGHTED IN ERN LARIMER AND WELD COUNTY BUT THEY DO APPEAR TO BE MOVING N. WILL WAIT AND SEE WHAT SAT PIX SHOWS AT PRESS TIME BEFORE COMMITTING TO MRNG LOW CLDS IN ZONES. PRESENTLY LEANING TO MENTN ONLY IN ZONES 42-44...48 AND 50. LOW CLOUDS SHUD DISSIPATE BY 9 OR 10 AM. WITH SLY FLOW...FAIR AMT OF SUN AND SOME WAA EXPECT TEMPS TO CLIMB WELL ABOVE YESTERDAYS HIGHS WHICH AGREES WITH NUMERICAL GDNC. PREFER WARMER FAN OVER FWC FOR TODAYS TEMPS. BOODA LONG TERM DISCUSSION: MDLS RMN SIMILAR IN FCST TRACK OF THIS SLOW MOVING CLOSED LOW...MOVING IT INTO THE OKLAHOMA PANHANDLE BY 00Z FRI. NERN CO IS STUCK IN MORE OF A DEFORMATION AREA AS THIS STORM SYSTEM RMNS S AND E OF THE CWA. ETA TRIES TO DRY THE AMS OUT AFT 12Z THU WITH THE FCST SNDG VEERING WINDS ARND TO THE W. THE NGM AND AVN MAINTAIN A DEEP MSTR OVER CO TNGT AND MOST OF THU AS WNDS RMN ESELY THRU THE PD. BST POTENTIAL FOR SHOWERS WL RMN OVR SRN AND ERN PORTIONS OF THE CWA TGNT AND THU. ONLY FVBL FACTORS FOR SHOWERS WOULD APPEAR TO BE THE WEAK ESELY UPSLOPE THE MDLS GENERATE AND THE DEFORMATION ZONE THAT STICK OVR NERN CO. ON THE FLIP SIDE...THE QG FORCING APPEARS MINIMAL AND MID LVL INSTBY OVR NERN CO IS FAIRLY WEAK. SO FAR...THE MDLS HAVE CONSISTENTLY OVERDONE THE QPF FOR OUR CWA AND ARE PROBABLY DOING SO ATTM. AVN FINALLY SWINGS WNDS ARND TO THE NW FRI EVNG AS SYSTEM MOVES FURTHER E SO SHUD SEE SOME PARTIAL CLRG BY FRI AFTN...AT LEAST ACRS WRN SECTIONS OF THE CWA. AVN WEAKENS THE NEXT SYSTEM OFF THE PACIFIC NW COAST AS IT MAKES ITS WAY INLAND. AS A RESULT...BST CHC FOR ANY PCPN WITH THIS STORM FRI WL BE CONFINED TO THE MTNS. NEXT TROF SET TO DROP INTO THE GREAT BASIN AND CLOSE OFF SUNDAY INTO MON. SEE NO REASON TO MAKE ANY CHANGES TO THE EXTENDED ATTM. COOPER .DEN...NONE. co EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1000 AM WED MAR 22 2000 E-W BAND OF LOW CLOUDS CONTINUES TO MOVE DOWN THE PENINSULA AND SHRINK. SATELLITE TREND REVEALS BAND WILL AFFECT SOUTHERNMOST COUNTIES NEXT HOUR OR SO...FOLLOWED BY RAPIDLY IMPROVING SKY CONDITIONS. BUOYS N OF CWA INDICATE PASSAGE OF NE WIND SURGE OVER LAST FEW HOURS. 13Z RUC SHOWS ONSET OF GUSTY NE FLOW SPREADING N-S ACROSS CWA THIS AFTERNOON AND EARLY EVENING...THEN PERSISTING FOR SOME TIME AS TIGHT GRADIENT TAKES HOLD. WILL UPDATE ZFP SHORTLY TO REMOVE EARLY MORNING LOW CLOUDS AND FOG CENTRAL AND SOUTH. ONSHORE FLOW AND SHALLOW MOISTURE SHOULD PROMOTE PARTLY CLOUDY SKIES TODAY. FIRE WX...WILL MAINTAIN INTERIOR FIRE WX WATCH FOR THE TIME BEING..BUT EXPECT TO CANCEL AT LEAST A PORTION OF THE WATCH WITHIN NOON SMF PRODUCT. ALTHOUGH 12Z TBW SOUNDINGS STILL DRY...XMR SOUNDING SHOWS LOW LEVELS MOISTENING..AND WITH DEVELOPMENT OF INCREASING NE FLOW THIS AFTERNOON...GREATEST THREAT FOR MARGINAL WARNING THRESHOLD WILL BE NORTHERN INTERIOR COUNTIES. MARINE...FORECAST WILL REMAIN UNCHANGED...HOWEVER WILL HEADLINE SCEC FOR NORTHERN LEG THIS AFTERNOON FOR INCREASING WIND/SEAS. SCA LIKELY ON NEXT PACKAGE AS WIND/SEAS CONTINUE TO BUILD. RIP CURRENT THREAT WILL REMAIN GREATER THAN NORMAL THIS AFTERNOON DUE TO RESIDUAL LONG PERIOD SWELL AND ONSHORE FLOW TRAJECTORY. .MLB...FIRE WEATHER WATCH THIS AFTERNOON FOR ORANGE/LAKE/SEMINOLE/ OSCEOLA AND INTERIOR VOLUSIA COUNTIES. AVIATION/FIRE WX...BRAGAW PUBLIC/MARINE......SPRATT fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 900 AM CST WED MAR 22 2000 SATELLITE THIS MORNING SHOWS THAT CONVECTION HAS DECREASED AND CLOUDS HAVE RAPIDLY THINNED OUT OVER THE FORECAST AREA. THE EXCEPTION IS THE FAR SOUTHERN COUNTIES WHERE A PERSISTENT BAND OF SHRA/TSRA CONTINUES TO SAG VERY SLOWLY SOUTH. RUC INDICATES A SERIES OF WEAK WAVES MOVING THROUGH RIDGE ACROSS AREA TODAY AND WITH SOME SCATTERED SHRA STILL UPSTREAM A CHANCE OF SHOWERS WILL PERSIST ACROSS THE FORECAST AREA TODAY. WILL UPDATE TO DECREASE CLOUDS AND POPS A LITTLE MOST AREAS BASED ON CURRENT TRENDS. WILL BREAK OUT A GROUP OVER THE FAR SOUTH TO GO LIKELY POP THIS MORNING. NO OTHER CHANGES. .JAN... MS...NONE. AR...NONE. LA...NONE. ms AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1035 AM CST WED MAR 22 2000 VISIBLE SAT LOOPS SHOWING SOME DISSIPATION TO CLOUDS ALONG AND WEST OF KMML TO KYKN LINE. WOULD EXPECT TREND TO CONTINUE BASED ON DECREASING LOW LEVEL RH FORECAST FROM 12Z RUC. 12Z RAOBS FROM KABR AND KOMA INDICATE POTENTIAL TO REACH 60 DEGREES...POSSIBLY EVEN TOP IT IN THE WEST WHERE SUNSHINE WILL BE MROE PREVALENT. WITH PARTIAL SUNSHINE EXPECTED THIS AFTERNOON...WILL UPDATE TO RAISE TEMPS A BIT MOST AREAS. THICKER CLOUDS AND STILL SOME LOW STRATUS/FOG OVER MOST OF NWRN IA...AND SMALL PART OF SWRN MN...WILL PERSIST LONGER AND KEEP TEMPS DOWN A LITTLE FROM AREAS FARTHER WEST. ALSO A FEW LIGHT RAIN SHOWERS ON KOAX RADAR AROUND AND JUST SOUTH OF KSUX AREA...SO WILL PUT A MENTION OF THIS IN KSUX ZONE THROUGH EARLY AFTN. .FSD...NONE HAMEN sd NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 200 PM MST WED MAR 22 2000 SHORT TERM DISCUSSION...RADAR LOOPS THIS AFTN SHW A LRG MASS OF PCPN CONTG TO MOVE NWD TWD AREA FM SERN CO BUT MST OF THIS PCPN IS DISIPATING AS IT MOVES OVR PALMER DVD. HWVR SUM SNW SHWRS HAVE MOVED INTO PARK AND SUMMIT COUNTIES. MDLS CONT TO SKIRT MST OF THIS PCPN TO S AND E OF METRO DEN TNGT AND WILL GO ALG WITH THIS IDEA. WILL GENLY FVR MESOETA SOLUTION ATTM WHICH SHWS A BRIEF SHOT OF PCPN OVR METRO DEN THIS EVE AND GREATER AMTS FRTHR E THRU THE NGT. MDLS ALSO KEEP MST OF PCPN OVR PLAINS IN FORM OF RAIN TNGT WITH ONLY THAT AMT NR ERN FTHLLS AS SNW. CANNOT ARGUE TOO MUCH WITH THIS BUT WITH LO TEMPS IN LWR 30S MUST MENTION RAIN CHNGG TO SNW LATE. GARD...WFO BOULDER LONG TERM DISCUSSION: UPR LVL LOW OVER XTRM SERN AZ IS SLOWLY BEGINNING TO LIFT OUT AS FCST BY YSTDY'S MDLS WITH THE APCH OF A BROAD TROF TWD THE W COAST AS WELL AS ANOTHER WAVE IN THE SUBTROPICAL JET STREAM WEST OF BAJA. MRNG UPR LVL PLOTS AND LATEST RUC SHOWS STRONGEST 300 MB JET MOVING AROUND TO THE BASE OF THE UPR LOW THIS AFTN. DECENT UPR LVL FORCING EAST OF THE SYSTEM WITH AN UPR LVL JET MOVING INTO ERN CO BUT DESPITE INCRSG UPSLOPE ON PROFILER PCPN RMNS S OF FCST AREA ATTM. UNFORTUNATELY THE UPR LOW SHIFTS TO THE EAST BEFORE BGNG ITS NE MOTION AFTER 00Z AND THIS RESULTS IN A TRACK THAT WILL TAKE THE UPR LO JUST A BIT TOO FAR E TO BRING ANY SUBSTANTIAL PCPN TO MOST OF OUR FCST AREA. MODELS ARE ALL IN REMARKABLE AGREEMENT WITH THE TRACK OF THE UPR LO...THO DIFFER A BIT IN THE AMNT OF PCPN THAT GETS WRAPPED ARND SYSTEM INTO ERN CO. ETA MIGHT BE CUTTING MSTR OFF A BIT TOO SHARPLY BASED ON HOW IT IS HANDLING CRNT 700 MB FLOW IN SERN CO BUT WUD TAKE A SUBSTANTIAL SHIFT IN THE FCST FOR ANY SIG PCPN NEAR THE FRONT RANGE. PROB ENUF UNCERTAINTY...WRAPARND MSTR AND UPSLOPE FLOW TO HAVE POPS ABT AS PER CRNT FCST FOR THU EXCEPT WILL NEED TO UP THE POPS FAR ERN ZONES LIKE 48..49 AND 50 WCH ARE CLOSE TO SOME VERY SUBSTATIAL PCPN THAT WILL HIT WRN KS. NOT SURE ABOUT THE CLEARING FOR THU AS EARLY AS INDC IN THE CRNT FCST...IT CUD HAPPEN BUT THE ETA WUD HAVE TO EXACTLY VERIFY OVER ANY OTHER MODEL AND APRS TO BE A TAD FAST. THE UPR LO WILL CARRY COLD AIR WITH IT BUT BECAUSE IT TRACKS OVER N TX AND SW KS IT SHD RMN TOO WARM FOR ANY SNOW WHERE THE MOST PCPN WUD FALL FARTHER TO THE E IN NERN CO. MIXED BAG IN AREAS WHERE THERE IS A CHC OF LGTER PCPN BUT AGAIN POPS WILL BE LESS THAN 50 PCNT. FOR THE MTNS DON'T SEE MUCH AS MOST PCPN SHD RMN TO THE SE OF EVERYTHING XCPT MAYBE INTO ZN 36..37 AND PERHAPS PARTS OF 34. CLRG THU NGT BUT WK TROF ACRS AREA ON FRI SO CHC OF MTN SNOW SHWRS. CUD BE A SURGE FM THE N INTO NERN CO LWR ELEVATIONS BUT NGM SEEMS SMWHT OVERDONE WITH THIS VS OTHER MDLS AND WILL KEEP IT DRY FOR NOW. LONGER TERM SATURDAY STILL LUKG WARMER AND DRY AHEAD OF THE NEXT UPR LOW. THE HI PRES TO OUR N CUD SNEAK DOWN ONTO THE PLAINS SAT IF IT DOESN'T ON FRI AND BRING A BIT COOLER TEMPS BUT FOR NOW WILL STICK WITH THE WARMER FCST CRNTLY IN THE EXTENDED AS PER AVN MODEL SLTN. MDLS IN GNL AGREEMENT WITH THE TIMING OF THE NEXT SYSTEM...MOVING AN UPR LO INTO NM BY LATE MONDAY. SFC HI NOT IN PLACE FOR BRINGING ANY COLD AIR TO LOWER LEVELS SO WUD DEPEND ON TRACK OF UPR LO FOR AMNT OF PCPN AND TYPE...PROB MOSTLY RAIN AT LOWER ELEVATIONS EAST OF THE FRONT RANGE...BUT OF COURSE MUCH CUD CHANGE BY MONDAY. SZOKE .DEN...NONE. co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 255 PM CST WED MAR 22 2000 LATEST SFC AND MSAS ANALYSIS INDICATING DIRTY SFC HIGH CENTERED OVER NORTHERN IL...STILL INFLUENCING REGION/S WX WITH LOW-LEVEL MOISTURE /STRATOCU DECK TRAPPED UNDER H9-H85 INVERSION. VIS LOOP DOES SHOW BREAKS BUILDING ACRS SOUTHWEST HALF OF CWA...ALTHOUGH HIGHER LEVEL STRATOCU DECK STREAMING IN FROM SOUTHWEST ALONG RUC H7-H3 MB THICKNESS FIELDS ACRS SOUTHEAST NE AND SOUTHWEST IA. AT LEAST TODAY A LITTLE MORE IN THE WAY OF SFC FLOW AND THUS BETTER VISIBILITIES...ALTHOUGH WEAK AT BEST. FCST CONCERNS CONTINUE TO BE SKY COVER...POSSIBLE FOG...AND EVENTUAL PRECIP CHANCES LATER IN FCST. IN SHORTER TERM FOR TONIGHT...FEEL MOSTLY CLOUDY/CLOUDY CONDITIONS WILL CONTINUE TO PREVAIL...ALTHOUGH BREAKS WILL BE POSSIBLE FROM TIME TO TIME...ESPECIALLY ACRS THE SOUTH. MODELS AGAIN HANDLING LOW LEVEL RH FIELDS RATHER POORLY...BUT WILL TRY AND GET GENERAL CONSENSUS. ETA AND NGM H85-H5 LMRH/S INCREASE OVERNIGHT...PROBABLY DUE TO MID LEVEL CLOUDS ADVECTING IN FROM CENTRAL PLAINS. MODELS ACTUALLY PROG H85 RH/S TO DRY OUT OVER THE SOUTH HALF OF THE CWA OVERNIGHT BEFORE INCREASING AGAIN ON THU...BUT BOUNDARY LAYER AND H925 RHS KEEP AT 70+ VALUES OVER MOST OF CWA OVERNIGHT. FCST SOUNDINGS DO SHOW WEAKENING INVERSION TONIGHT...BUT QUICKLY GETS REINFORCED DURING DAY ON THU AS H8- H7 FLOW VEERS TO SOUTHWEST AND INCREASES...WITH LOW LEVEL MOISTURE ONCE AGAIN TRAPPED. AT THIS POINT...HARD TO BELIEVE ANY RH PROG BUT FEEL MOSTLY CLOUDY WORDING FOR TONIGHT AND THU THE WAY TO GO...ALTHOUGH PERIODS WITH BREAKS IN DECK DEFINITELY POSSIBLE. ALSO WATCHING SCTRD SPRINKLES ACRS NORTH-CENTRAL MO MOVING NORTHEAST...BUT NOT SURE THEY WILL HOLD TOGETHER TO AFFECT SOUTHERN CWA. WILL WATCH TREND TOWARD ISSUANCE TIME. WILL LEAN TOWARD WARMER FWC FOR LOWS TONIGHT. FEEL FOG WILL BE LIGHT ENOUGH TONIGHT NOT TO MENTION IN ZONES/MUCH LIKE LAST NIGHT/ WITH CONTINUING LIGHT SFC FLOW AND CLOUD COVER...ALTHOUGH IF MORE BREAKS DVLP AND PERSIST...SOME PATCHY DENSE POSSIBLE. SHORT RANGE MODELS HAVE GOOD AGREEMENT IN LIFTING WELL ADVERTISED SOUTHWEST CUT-OFF LOW OUT OF GRT BASIN AFTER 12Z THU AS 100+ KT H3 JET MAX ROUNDS IT/S BASE...AND UPSTREAM KICKER BOOTS IT/S WAY INTO THE SOUTHWEST. UPPER SYSTEM LOOKING TO WEAKEN AS IT LIFTS UP AGAINST SHARP UPPER RIDGE AND SHOULD REACH A SOUTHEAST NE POSITION BY 12Z FRI. WEAK VORT PIECES LOOK TO SHEAR OUT ACRS IA ON THU OUT OF MAIN VORTEX WITH LITTLE IMPACT. MAIN VORT THAN PROGGED TO PROGRESS TO NORTHEAST KS BY 12Z FRI. AS SYSTEM PULLS UP...FEEL ETA TOO AGGRESSIVE SPILLING PRECIP NORTHEAST ACRS WESTERN CWA AFTER 06Z FRI...WHILE AVN AND NGM KEEP PRECIP WEST OF CWA THROUGH 48 HRS. DVLPNG DRY EAST-SOUTHEAST SFC FLOW THU NIGHT MIGHT HOLD PRECIP AT BAY FOR AWHILE TO THE WEST AND SOUTH... PRECIP MIGHT FOCUS MORE UNDER UPPER LOW AND ALONG SFC WARM FRNT SETTING UP OVER MO...ALTHOUGH THIS FEATURE NOT VERY WELL DEFINED AND LOOKING TO EVENTUALLY OCCLUDE. LOW LEVEL THTA-E ADVECTION TO INCREASE ACRS EAST IA AFTER 06Z FRI ON NOSE OF DVLPING SOUTHERLY H85 FLOW...AS WELL AS LOW LEVEL CONVERGENCE. MAY CONTINUE LOW POPS FOR JUST SHOWERS ACRS SOUTHWEST 2/3'S OF CWA LATE THU NIGHT AS INSTABILITY LACKING AND BEST UPPER DIFFLUENCE FROM LEFT EXIT REGION LOOKS TO SET UP OVER SOUTH HALF OF MO. POSITIVE OMEGAS DO INCREASE TOWARD 12Z FRI AND AFTER...AND WITH UPPER SYSTEM ROTATING ACRS CENTRAL AND EASTERN IA ON FRI AND IT/S ASSOCIATED COOLER POOL OF AIR ALOFT...MID LEVEL INSTABILITIES SHOULD DECREASE. WILL KEEP THUNDER WORDING IN FOR FRI WITH LIKELY POPS. PRECIP LOOKS TO EVOLVE INTO POST FRONTAL NATURE LATER FRI NIGHT...WITH SOUTHERN THIRD OF CWA POSSIBLE EVEN GETTING DRY SLOTTED WITH A BREAK IN THE ACTION FOR AWHILE. AS FOR TEMPS...WILL LEAN TOWARD SLIGHTLY COOLER FAN HIGHS FOR THU WITH CONTINUING CLOUD COVER...ALTHOUGH SOME SUN IN LOCATIONS WILL SUPPORT LOCALLY WARMER READINGS. ...EXTENDED...SAT-SUN-MON... AS LONG RANGE MODELS CORRECTLY SLOW DOWN THEIR RESPECTIVE SOLUTIONS OF EJECTING SOUTHWEST SYSTEM OUT ACRS THE MIDWEST AT WEEK/S END...FEEL EVEN SLOWER MRF IN HANDLING ASSOCIATED SFC AND UPPER LEVEL SYSTEM BETTER. EUROPEAN...CANADIAN GEM AND MRF ALL PULL OUT CLOSED SOUTHWEST SYSTEM IN A NEGATIVELY TILTED FASHION AS IT TRIES TO PHASE WITH NORTHERN STREAM LATE FRI INTO SAT..BUT THEN WEAKEN IT QUICKLY AS IT FEELS BRUNT OF SHARP UPPER RIDGE TO THE EAST. WHILE CANADIAN AND EURO WHIRL SYSTEM AND IT/S ASSOCIATED MOISTURE THROUGH CWA QUICKER FOR A MAINLY DRY SAT...DO LIKE SLOWER MRF WITH LINGERING SHOWERS FOR SAT. ACTIVITY MAY BE RESTRICTED TO SAT MORNING AND MAY WORD 1ST DAY OF EXTENDED ACCORDINGLY. WITH CLOUDS AND LINGERING PRECIP...AS WELL AS CAA AT LOWER LEVELS...FEEL MILD MRF HIGH TEMP VALUES BIT HIGH FOR SAT. MRF...CANADIAN AND EURO ALL REASONABLY SIMILAR IN BUILDING LARGE PACIFIC NORTHWEST SFC HIGH ACRS THE UPPER MIDWEST SAT NIGHT AND SUN AS NEXT CUT-OFF SOUTHWEST SYSTEM DROPS DOWN AND SETS UP SHOP OVER THE NORTHERN BAHA. THIS WOULD INDUCE ANOTHER PERIOD OF UPPER RIDGING OVER THE MID TO UPPER MS RVR VALLEY THROUGH SUN...ALTHOUGH ACTIVE NORTHERN STREAM ACRS SOUTHERN CANADA LOOKS TO LIMIT NORTHERN EXTENT SOMEWHAT UNTIL SOUTHWEST SYSTEM STARTS TO PULL OUT. THUS DRY AND MILD WX APPEARS TO BE ON TAP FOR THE REST OF THE EXTENDED PERIOD. MRF AND EURO LOW LEVEL THERMAL PARAMETERS SUPPORT UPPER 50S-LOWER 60S ON SUN... ESPECIALLY WITH LATE MARCH INSOLATION. BOUNDARY LAYER AND H85 TEMPS CHANGE LITTLE...OR JUST WARM SLIGHTLY ON MON AS SFC RIDGE SLIDES ACRS THE EASTERN GRT LKS WITH A HINT OF RETURN FLOW BRUSHING THE CWA. .DVN... IA...NONE. IL...NONE. MO...NONE. HLADIK il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 415 PM EST WED MAR 22 2000 12Z RAOBS/LATEST WV LOOP SHOWS POLAR BRANCH FLOW ACRS SRN CAN WITH BLOCKY SRN STREAM FEATURING CUTOFF LOWS OVR SE AZ...NC CST AND WRN ATLANTIC NR BERMUDA. STRG SHRTWV EMBEDDED IN NRN BRANCH NOW MOVG THRU ONTARIO...BUT BEST DRYING/UPR CNVGC REMAINING TO N. CWA IN CONFLUENCE BTWN MORE WLY FLOW ACRS LK SUP AND MOIST SWLY FLOW IN WI ON NRN FLANK OF SFC HI TO S. ASSOCIATED MSTR CNVGC/ADVCTN ACRS CNTRL CWA HAS RESULTED IN STUBBORN LO/MID DECK OF CLD. BRK IN CLD WHICH HAD DVLPD ACRS NRN WI/SE ZNS HAS FILLED IN. NW PART OF CWA CLOSE ENUF TO UPR CNVGC ASSOCIATED WITH ONTARIO SHRTWV HAS CLRD OUT WITH STABILIZING OR DOWNSLOPE WLY FLOW OFF LK SUP. EDGE OF CLRG LINE MOVG SLOWLY EWD. FLOW ACRS NE MN STILL MAINLY WSWLY WITH SFC DWPTS THERE ONLY A BIT LWR THAN OVR CWA. MAIN FCST CONCERN TNGT IS CLD TRENDS/TEMPS. LATEST RUC AND 12Z ETA GUIDANCE SHOWS H925 WNDS TURNING MORE WNWLY ACRS NRN CWA THIS EVNG AS SHRTWV AXIS MOVES E OF CWA LONGITUDE. ALTHOUGH BEST UPR CNVGC REMAINS TO N...THIS FLOW SHUD ALLOW CLRG LINE TO PROGRESS FURTHER E WITH TIME...SO HAVE GONE MCLR/PCLDY IWD-KEWEENAW ZNS-MQT AND PARTIAL CLRG ALGER/LUCE. BUT SUSPECT CLD WL BE MORE STUBBORN ACRS SRN TIER WITH LLVL CNVGC AXIS REMAINING THERE. HI DWPTS UPWND REINFORCE CONFIDENCE CLD WL LINGER ACRS SRN TIER. FCSTG PTCHY FOG TO REDVLP THOSE PLACES THAT DIDN/T WARM/MIX SGNFTLY TDAY AND TEMPS GENERALLY NR MOS ACRS N WHERE SKIES CLR BUT ABV MOS TO S. ETA HAS HAD BEST HANDLE ON LLVL MSTR TRENDS LAST SVRL RUNS WITH DRYING MORE RELUCTANT TO SPRD S...SO FOLLOWED ITS GUIDANCE FOR CLD FCST TMRW. ETA 290K ISENTROPIC SFC PROGS SHOW INCRSG SLY COMPONENT AND MSTR RETURN DURG THU...SO HAVE KEPT SKIES MCLDY ACRS S AND WENT WITH BCMG MSTLY CLDY ACRS N. LACK OF ANY UPR DYNAMICS WITH BLDG HGTS/DRY MID/UPR LYRS WL PRECLUDE ANY PCPN. SINCE NGM IS SLOWER WITH MSTR RETURN...ASSUMING MORE CLD THAN FWC AND GOING WITH TEMPS LWR THAN FWC FOR MAX...ESPECIALL NR LK MI SHORELINE WITH SWLY FLOW GRDLY BCMG SE OFF COOL WATER. CONTD SWLY FLOW TMRW NGT...SO MORE CLDS WITH TEMPS A BIT ABV MOS GIVEN FCST LLVL DWPTS. ETA SHOWS AXIS OF HIER H85 DWPT/H100-7 MSTR CNVGC/H85-5 QVECTOR CNVGC MOVG THRU WCNTRL ZNS OVRNGT...SO ADDED MENTION OF SPRINKLES AFTR MIDNGT. MORE FOG FOR SE ZNS WITH CONTD MOIST FLOW ACRS LK MI. MODELS IN GOOD AGREEMENT ON TIMING OF SW CUTOFF WITH SYS PROGGED TO REACH NE KS BY F48. ETA SHOWS MSTR AXIS PASSING TO N DURG FRI MRNG... SO WORDED MRNG SPRINKLES WCNTRL. USED AVN FCST H2-3 DVGC TO TIME ARRIVAL OF SHRA CHCS OVR CWA...EARLY AFTN SW TO LATE IN DAY ACRS E. FCST MAX NR MOS GUIDANCE. EXTENDED MODELS NOW ALL IN AGREEMENT SHOWING SHRTWV IN NRN BRANCH APRCHG WRN LKS ON SAT AND AT LEAST PARTIALLY PHASING WITH REMNANTS OF SW LO LIFTING NEWD WHILE DEEP CUTOFF LO DVLPS OFF SE CAN. SINCE MRF ADVECTS H85 DWPT APRCHG 7C INTO SYS WITH SSI DOWN TO NR 0...WL UPGRADE SHRA THREAT TO LIKELY FOR FRI/SAT AS SFC WAVE MOVG IN ALG COLD FNT. MODELS ALSO INDICATE MDT CAD/DRYING IN ITS WAKE FOR SUN AS HI PRES BLDS IN. SINCE BLOCK OVR SE CAN APPEARS TO DVLP FAR ENUF S SO THAT NRN BRANCH CAN REMAIN MORE PROGRESSIVE AS MODELS FCST...WL REMOVE PCPN MENTION ON SUN FOR ALL BUT ERN ZNS EARLY WITH INCRSG SUNSHINE W-E. MODELS SHOW BLDG RDG OVR WCNTRL CAN AHD OF NXT SHRTWV SPINNING OFF GLFAK LO...WHICH ALLOWS FOR ENHANCED NWLY FLOW ACRS ERN CAN EARLY IN WEEK. A BACK DOOR TYPE COLD FNT MAY PASS MON-TUE AS SHRTWV DIGS SEWD...ESPECIALLY SINCE MRF/CANADIAN ENSEMBLES SHOW H5 TROF AXIS FARTHER W THAN OPERATIONAL MODELS. BUT WL KEEP PCPN OUT WITH DRY AIRMASS IN PLACE AND EVEN ERN CWA ON ACYC SIDE OF JET AXIS. COORDINATED WITH APX/GRB. .MQT...NONE. KC mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 1215 PM CST WED MAR 22 2000 SATELLITE INDICATES THAT CLOUDS CONTINUE TO RAPIDLY DECREASE OVER MUCH OF THE FORECAST AREA. LATEST RUC INDICATES CONTINUED MID/UPPER LEVEL DRYING ACROSS REGION THROUGH THE DAY. SATELLITE STILL SHOWS SOME MID LEVEL CONVECTIVE ELEMENTS OVER SW AND SE PARTS OF FORECAST AREA...SO WILL RETAIN SOME VERY LOW POPS THESE AREAS THIS AFTERNOON. ELSEWHERE...WILL GO MOSTLY SUNNY AND RAISE TEMPS A LITTLE. .JAN... MS...NONE. AR...NONE. LA...NONE. 08 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 1000 AM EST WED MAR 22 2000 LATEST RUC AND MESO-ETA CONTINUE TO SHOW WEAK 925-MB THERMAL TROUGHING AND NORTHEAST FLOW DOWN THE NORTHERN TENNESSEE VALLEY THIS MORNING...INCLUDING SECTIONS OF SOUTHWEST VIRGINIA. THESE SHORT-TERM MODELS WEAKEN THE THERMAL TROUGHING AND RELATIVE HUMIDITY THIS AFTERNOON. HOWEVER...THE SWATH OF LOW CLOUDS ON THE BACK SIDE OF THE MIDDLE ATLANTIC COASTAL LOW IS QUITE IMPRESSIVE. SO...FOR THIS AFTERNOON...WILL MAINTAIN THE MOSTLY CLOUDY WORDING IN THE NORTHEAST. ELSEWHERE...EARLY 22/12Z MODEL INFORMATION IMPLIES MOSTLY SUNNY AFTERNOON SKIES. HOWEVER...CONSIDERING THAT CLOUDS FROM THE NORTHEAST ARE EFFECTIVELY ADVECTING SOUTHWEST...WILL MAINTAIN THE PARTLY SUNNY WORDING. IN TERMS OF TEMPERATURES...WILL LOWER FIRST PERIOD MAXES A LITTLE. .MRX... NC...NONE. TN...NONE. VA...NONE. DM tn AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE LUBBOCK TX 1245 PM CST WED MAR 22 2000 RUNNING BEHIND THE POWER CURVE SO WILL KEEP THIS SHORT. LATEST SURFACE ANALYSIS SHOWS COLD FRONT JUST SOUTH OF AN ALTUS TO HOBBS TO KGDP LINE AT 18Z. WARM FRONT WAS LOCATED FROM SOUTH OF MIDLAND TO BETWEEN ABILENE AND SAN ANGELO. THUNDERSTORMS ARE FORMING JUST NORTH OF THE WARM FRONT NORTH OF MIDLAND ATTM. WITH MEAN STEERING FLOW FROM THE SOUTH EXPECT THIS ACTIVITY WILL MOVE NORTHWARD AND INCREASE AS IT MOVES TOWARD THE SOUTH PLAINS. UPPER LOW IS OVER SOUTHEAST ARIZONA ATTM AND HAS NOT SHOWN AN EASTWARD MOVEMENT YET BUT IS EXPECTED TO KICK OUT TO THE EAST ACROSS SOUTHERN NEW MEXICO TONIGHT. ELEVATED SEVERE THUNDERSTORMS ARE THE MAIN CONCERN FOR THIS AFTERNOON AND EVENING THEN TURNING INTO HEAVY RAIN EVENT TONIGHT. 15Z RUC SHOWS UNSTABLE AIRMASS WILL ADVECT NORTHWARD INTO THE REGION ABOVE THE SHALLOW COLD AIR AT THE SURFACE. THIS IS DEPICTED BY SHOWALTER INDICES DECREASING TO A -5 TO -9 DEGREES RANGE BY 03Z FROM THE SOUTHEAST TEXAS PANHANDLE SOUTH-SOUTHWEST TO THE PERMIAN BASIN. COUPLED UPPER LEVEL JET STRUCTURE WILL MAXIMIZE THE UPPER LEVEL DIVERGENCE OVER THE AREA BY 06Z. LIFT ASSOCIATED WITH LOW LEVEL WARM AIR ADVECTION/ISENTROPIC UPGLIDE WILL INCREASE OVER THE SOUTH PLAINS TONIGHT. 12Z AVN MODEL CONTINUES TO BULLSEYE A REGION OF 20 MICROBARS/SECOND AT 06Z. WILL CONTINUE MENTION OF LOCALLY HEAVY RAINFALL TONIGHT. DUE TO ELEVATED NATURE OF STORMS LARGE HAIL APPEARS TO BE THE MAIN SEVERE THREAT FOR MOST OF THE SOUTH PLAINS AND ALL OF THE LOW ROLLING PLAINS THIS AFTERNOON AND EVENING. .LBB...NONE. TINSLEY tx