WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 130 PM MST WED FEB 23 2000 NEXT PACIFIC SYSTEM IS KNOCKING AT THE DOOR. THIS ONE IS LOOKING A BIT STRONGER. PRECIP WILL START IN THE SOUTHERN ZONES LATE TONIGHT AND IN THE CENTRAL-NORTHERN ZONES THURSDAY. ADVISORY CRITERIA LIKELY TO BE MET IN ALL MTNS AND CLOSE TO 12 INCHES IN NORTHERN- CENTRAL MTNS BY SAT MORNING. WILL ISSUE AN ADVISORY FOR SOUTHERN AND CENTRAL MOUNTAINS FOR THURSDAY-THU NIGHT. DETAILS: MODELS IN GOOD AGREEMENT...THOUGH TIMING MAY BE TOO FAST. JET STREAKS SEEN DIGGING INTO THE BACKSIDE OF TROF AND RUN-TO-RUN SLOW DOWN ARE THE EVIDENCE. 18Z RUC IS SLOWER THAN AVN/NGM. ETA TIMING DISCOUNTED. SO SCENARIO WITH TIMING SLOWED A BIT...SHORTWAVE DIGS TO YUMA LATE TONIGHT AND THEN BEGINS TO LIFT. FRONT LOOKS MORE VIGOROUS THAN PREVIOUS SYSTEM APPROACHING THE FOUR CORNERS AFTER 15Z AND PASSING THRU ALL OF FORECAST AREA BY OOZ. FRONTAL FORCING STRONGEST SOUTH...THOUGH NO LIGHTNING SEEN WITH FRONT YET IN SOUTHERN CA. CENTRAL MTNS TO NOT BEGIN TO ACCUMULATE SNOW UNTIL LATER THURSDAY MORNING. SNOW LEVEL TO START HIGH TONIGHT...9000FT AND LOWER BEHIND THE FRONT TO 7000FT THU AFTERNOON. AFTERNOON LAPSE RATES LOOK STEEP ENOUGH FOR GOOD CONVECTIVE HEAVY SHOWERS. STRONG VEERING WINDS WILL MAKE THE ADVISORY A BLOWING SNOW TYPE. THURSDAY EVENING ACCUMULATIONS WILL TAPER IN SOUTHERN MTNS BUT CONTINUE IN CENTRAL MTNS AND BEGIN IN ERNEST NORTHERN MTNS. SECOND STRONG SHORTWAVE DROPS INTO BACK OF TROF LATE FRIDAY TO ENHANCE COLD ADVECTION AND SNOW ACCUMULATION IN CENTRAL AND NORTHERN MOUNTAINS. IN EFFICIENT NORTHERN MOUNTAINS...SNOWS TO LINGER THROUGH FRIDAY NIGHT. HIGHLIGHTS LIKELY TO BE NEEDED HERE BUT WILL NOT ISSUE THIS FAR OUT. EXTENDED: NCEP LIKES THE MORE AMPLIFIED FLOW AND NO SPECTRAL IS MORE AMPLIFIED IN THE SOUTHERN BRANCH THAN THE MRF. IN BETWEEN SYSTEMS SATURDAY...LIGHT POPS SUNDAY WITH NEXT VIGOROUS TROF PASSAGE MONDAY. SNOW SOUL TRAIN KEEPS TRUCKIN. 99/RAMEY .GJT...SNOW AND BLOWING SNOW ADVISORY THURSDAY AND THURSDAY NIGHT UTZ28 (MOUNTAINS)...COZ009/010/012/018/019. co AREA FORECAST DISCUSSION 1105 AM EST WED FEB 23 2000 CLOUDS OVER ALABAMA APPEAR TO DRY UP AS THEY PUSH INTO UPPER RIDGE OVER N GA. LATEST RUC TIME CROSS SECTION NOT PROGGING AN INCREASE IN MOISTURE OVER THAT PART OF STATE EITHER. WILL ADJUST TWEAK ZONES TO JUST PARTLY CLOUDY IN NORTH. OTHERWISE ZONES APPEAR TO BE ON TRACK WITH TEMP AND WINDS...SO ONLY MINOR TWEAKS IF ANY THAT AREA. .ATL...NONE. DH ga AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE DES MOINES IA 828 PM CST WED FEB 23 2000 SHORT TERM... NEW ZONE SET WAS ISSUED, MAINLY TO ACCOUNT FOR LESS THUNDER AND EMPHASIZE PLAIN OLE RAIN. GOOD RAIN AT THAT, ALTHOUGH RADAR ESTIMATES MAY BE A LITTLE OVERDONE DUE TO THE FREEZING LEVEL ENHANCING REFLECTIVITY. SEVERAL PIREPS CAME IN WITH MDT SN AT AROUND 9KFT EARLIER. DEF ZONE LOOKS LIKE IT WILL ROTATE N INTO NORTHERN IA. 88D SHOWS VORT MAX CLEARLY NEAR CARROLL WITH THE BEAM AT AROUND 6KFT. FG IS A NEAR CERTAINTY IN MY OPINION AS THE SFC LOW LOOKS TO TRACK ACROSS NRN MO. SURFACE WINDS ARE BACKING TO AN EASTERLY COMPONENT WITH THE LATEST RUC SHOWING NEAR OR SATURATED LOW LEVELS ALL NIGHT. FWC ALSO HINTING AT THIS WITH CAT 1 VSBYS BY 12Z. MINOR TEMP CHANGES N TO ACCOUNT FOR CURRENT OBS AND DEW POINTS. .DSM...NONE KULA ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 955 AM CST WED FEB 23 2000 12Z MODEL ANALYSIS PAINTING A BLEAKER PICTURE OF RAIN CHANCES ONCE AGAIN. MOISTENING AND COOLING OF 850 TO 700 MB LAYER REQUIRED FOR CONVECTION. PROGRESSIVE AVN IN SYNC MORESO WITH RUC THAN ETA REGARDING MOISTURE CONVERGENCE AT THIS LEVEL. ANY TRANSIENT COOLING DURING AFTERNOON THIS LAYER SHOWN TO REVERSE BY EVENING. ASIDE FROM THIS...STEEP LAPSE RATES EVIDENT ON OUN MORNING SOUNDING AND BELIEVE THIS MID LEVEL COOLING TRANSLATE EAST AND MAY AFFECT FAR ENOUGH SOUTH TO CATCH ARKANSAS PORTIONS WHERE WILL LEAVE IN SLIGHT POP ENHANCEMENT. LOW LEVEL VEERING AND MODERATE MID LEVEL FLOW FAVORABLE FOR SEVERE WEATHER SHOULD ANYTHING DEVELOP. PRUDENTLY LEAVE AT LEAST WIDELY SCATTERED FOR EVERYONE THIS AFTERNOON BUT STINGY FOR THIS EVENING. WILL CLEAN UP WORDING ON ZONES OF MENTIONS OF THIS MORNING AND MAY ADJUST WINDS AS PRESSURE GRADIENT APPEARS TO BE RELAXING TO THE SOUTHWEST. TEMPS RATHER CONSISTENT IN LOWER 60S AT MID MORNING AND VARIABLE CLOUDS COULD MAKE FIDDLING WITH THESE TRICKY. VII .SHV...NONE. IV la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 1000 AM EST WED FEB 23 2000 KLWX RADAR SHOWING A DYING LINE OF LIGHT SHOWERS FROM FDK TO IAD TO CJR. KPBZ RADAR SHOWING ANOTHER AREA OF SHOWERS MOVING ACROSS SOUTHERN PA. 700 MB AND 500 MB PROGS FROM 06Z ETA AND 12Z RUC SHOWING A WEAK SHORT WAVE MOVING THROUGH THE AREA... EXPECTED TO MOVE EAST OF US SHORTLY AFTER 18Z. PRECIPITATION DISSIPATES AS IT MOVES INTO SURFACE RIDGE... SO NOT EXPECTING ANYTHING TO REACH THE GROUND TO THE SOUTH AND EAST OF DCA/BWI. WILL ADD A FEW SPRINKLES OR SOME LIGHT SHOWERS TO THE AFTERNOON FORECAST NORTH AND WEST OF THE CITIES. VIS LOOP SHOWING ONLY A FEW BREAKS IN THE CLOUDS OVER THE WESTERN AND FAR SOUTHEASTERN SECTIONS OF THE CWA. EXPECT THAT A FEW MORE BREAKS WILL SHOW UP AS SHORT WAVE MOVES OFF TO THE EAST... BUT WILL BE A LITTLE MORE PESSIMISTIC WITH CLOUDS THAN CURRENT FORECAST. WILL GO WITH EITHER A PARTLY CLOUDY OR A VARIABLY CLOUDY FORECAST FOR THE AREA THIS AFTERNOON. IN AREAS THAT HAVE SEEN SUN TEMPS HAVE RISEN INTO THE 50S ALREADY. AREAS THAT HAVE HAD CLOUDS AND SPRINKLES AREA STILL DOWN IN THE LOWER 40S. 12Z SOUNDINGS SHOW HIGHS IN THE LOWER 60S ASSUMING GOOD MIXING DURING THE AFTERNOON. WILL HAVE TO RAISE TEMPS FOR THE WESTERN 1/3 OF AREA AS CURRENT TEMPS ARE APPROACHING FORECAST MAX. WILL LIKELY LEAVE THE TEMPS AS IS ELSEWHERE.. AND HOPE THAT SUN DOESN'T TAKE OVER. .LWX...NONE. MARGRAF! md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1020 PM EST WED FEB 23 2000 FORECAST UPDATE ISSUED AT 1010 PM EST TO LOWER EXPECTED MIN TEMPS OVER INTERIOR NRN COUNTIES...TO RAISE MIN TEMPS OVER SRN COUNTIES... AND TO POSTPONE ARRIVAL OF SHOWERS UNTIL DAYBREAK. LATEST RADAR IMAGERY INDICATED ONLY ISOLATED SPRINKLES ACROSS LOWER MICHIGAN AND MUCH OF INDIANA AS OF 03Z. ORGANIZED PCPN WELL TO THE SW OVER MO BOOTHEEL REGION AND SERN IA. 00Z ETA AND 02Z RUC II RUNS HOLD OFF PCPN UNTIL AFT 12Z FOR THE FORECAST AREA. HOWEVER...GOOD DPVA MOVES INTO THE REGION AFT 09Z AND WITH ABUNDANT MOISTURE AROUND...SCATTERED SHOWER FORMATION STILL SEEMS REASONABLE. THEREFORE...30 PERCENT POPS MAINTAINED FOR LATE NIGHT TIME PERIOD FOR ENTIRE FORECAST AREA. WITH CLOUDS AROUND AND CONTINUED WARM AND MOISTURE ADVECTION OVERNIGHT FROM S-SERLY WIND FLOW...TEMPS LIKELY NOT TO FALL MUCH FROM CURRENT READINGS. EARLIER THIS EVENING... TEMPS FELL INTO UPPER 30S OVER NRN INTERIOR COUNTIES WHERE WIDESPREAD SNOWCOVER STILL EXISTS. HERE...READINGS WILL HOLD NEARLY STEADY OR RISE A FEW DEGREES OVERNIGHT. .GRR...NONE. GREENE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 400 PM EST WED FEB 23 2000 CONVECTIVE LOOKING AREA OF CLOUDS DEVELOPING ACROSS NORTHEAST IN AND NORTHWEST OH NOW. AM CONCERNED THAT THIS AREA COULD KICK OUT SOME SHOWERS EARLY THIS EVENING ACROSS SOUTHERN CWA. SUPPORT FOR SHOWERS IS OFFERED BY 18Z RUC THETA-E ADVECTION PATTERN. ALTHOUGH BY NO MEANS DEFINITIVE...THETA-E ADVECTION APPEARS TO BE SUFFICIENT TO KICK OUT A LIGHT SHOWER. FOR NOW WILL NOT INCLUDE IN ZONES. OTHERWISE...IR LOOP AND SURFACE REPORTS INDICATING MAINLY MID AND HIGH CLOUDS TO THE SOUTH OF CWA...WITH A FEW EMBEDDED BREAKS. EXPECT THESE CLOUDS TO MOVE ACROSS CWA DURING THE EVENING...OFFERING CONSIDERABLY CLOUDY SKIES. ETA SHOWS BEST THETA-E ADVECTION TO BE ACROSS SOUTHERN CWA OVERNIGHT...THEN MOVE NORTH ON THURSDAY. WILL CARRY CHANCE POPS ACROSS ENTIRE CWA TONIGHT...SHADING FROM HIGH CHANCE SOUTH TO LOW CHANCE NORTH. LOOKING AT TSRA POTENTIAL FOR OVERNIGHT...AXIS OF BEST ELEVATED INSTABILITY /850MB LI/ REMAINS NORTH AND SOUTH OF CWA. SO WILL NOT CARRY MENTION OF TSRA FOR OVERNIGHT. FWC/FAN TEMPS ACCEPTED. TOMORROW...NGM IS MOST AGGRESSIVE IN KICKING OUT QPF/S OF 3/4 TO 1 INCH ACROSS CWA...WHILE ETA OFFERS ONLY ABOUT 0.15 INCH. PW/S ON BOTH MODELS APPROACH 1 INCH...CERTAINLY HEALTHY FOR LATE FEBRUARY. CONTRIBUTING TO LARGE NGM PRECIP IS BROAD AREA OF HIGH MEAN RH...COVERING NEARLY ENTIRE LOWER MI...AND STRONG UVV. HIGHER MEAN RH MAY BE RESULT OF STRONGER GULF CONNECTION ON NGM THAN ETA PER ANALYSIS OF 295K SURFACE. LOOKING AT UVV FORCING...ISENTROPIC ASCENT...VORT ADVECTION AND TEMP ADVECTION...NGM LOOKS TO BE OVERDONE. AVN UVV FIELD INTERMEDIATE TO ETA AND NGM WITH UVVS AROUND 5 MB/SEC...AND THIS LOOKS REASONABLE. SO GIVEN MOISTURE AND LIFT...EXPECT POPS NEAR 100 PERCENT AS INDICATED BY FAN AND FWC. QPFS LIKELY TO BE MORE THAN 0.15 OFFERED ON ETA WITH 6 KM ETA SUGGESTING HALF INCH REASONABLE. WILL LEAVE RUMBLE OF THUNDER IN FORECAST. WITH MODEL CAPE NIL AND SURFACE LI/S IN POSITIVE TERRITORY NOT MUCH TO RECOMMEND TSRA. HOWEVER...AXIS OF ELEVATED INSTABILITY /ALBEIT WEAK/ DOES TRAVERSE CWA DURING THE DAY. HENCE SUFFICIENT JUSTIFICATION TO LEAVE IN RUMBLE OF THUNDER. FWC/FAN/2-M TEMPS AWAY FROM LAKESHORE LOOK GOOD. BUT WITH SOUTHEAST WINDS LIKELY TO TRANSPORT ICE CHILLED LAKE AIR INLAND...WILL ADD THE TYPICAL COOLER NEAR THE LAKE TO ALL LAKESHORE /HURON...ST CLAIR...AND ERIE/ COUNTIES. TOMORROW NIGHT...UPPER LEVEL SHORTWAVE TO CROSS CWA DURING THE EARLY EVENING...KEEPING CHANCE OF POPS IN FOR SOUTHERN ZONES AND LIKELY POPS TO THE NORTH. MODELS NOT OPTIMISTIC IN OFFERING CLEARING POTENTIAL FOR TOMORROW NIGHT...SO MOSTLY CLOUDY SHOULD WORK. WITH SURFACE TD DEPRESSIONS BASICALLY NIL...WILL ADD MENTION OF AREAS OF FOG. PREFER SLIGHTLY WARMER FWC/2-M ETA TEMPS TO COOLER FAN WITH CLOUDS EXPECTED TO HANG IN. FRIDAY...FWC AND FAN POPS IN THE 40S...BUT HARD PRESSED TO SEE MUCH FORCING SUFFICIENT TO WARRANT 40 POPS. WITH ATMOSPHERE REMAINING WARM AND SOUPY...A SHOWER IS NOT OUT OF THE QUESTION...SO WILL GO WITH 30 PERCENT POPS. TYPICALLY WITH FAN TEMPS EXCEEDING FWC TEMPS...SUCH AS THEY WILL BE...THAT/S A GREEN LIGHT TO GO ABOVE FWC TEMPS. WAA ADVECTION WILL BE KICKING IN DURING THE AFTERNOON SO WILL NUDGE TEMPS UP TO SLIGHTLY ABOVE WARMER FAN NUMBERS...WITH CLOUD COVER HOLDING ME BACK FROM MORE AGGRESSIVE TEMP INCREASE. IN THE EXTENDED... EXTENDED PERIOD TO BE CHARACTERIZED BY ABOVE NORMAL HEIGHTS...AND PROGRESSIVE PATTERN. MRF AND ETA-XX IN EXCELLENT AGREEMENT THROUGH FORECAST PERIOD...WHILE CANADIAN DIVERGES TOWARD END OF PERIOD. STRONG WAA ADVECTION...TAPPING GULF MOISTURE ON 50 KNOT 850 MB WIND SHOULD PRODUCE HIGH CHANCE POPS FRIDAY NIGHT AND LIKELY POPS SATURDAY. PROGRESSIVE SHORTWAVE TROUGH CROSSES CWA ON SUNDAY...KICKING OFF CHANCE OF RAIN SHOWERS. 1000-500 MB THICKNESSES SUPPORT SNOW...BUT 1000-850 MB INDICATE RAIN WITH LOWEST LAYERS REMAINING WARM. MODELS DEPART BEYOND SUNDAY AS CANADIAN PUSHES A SHORTWAVE TROUGH TOWARD CWA...WHILE MRF AND ETA-XX KEEP REGION UNDER INFLUENCE OF PROGRESSIVE UPPER LEVEL RIDGE. PREFER PERSISTENT PATTERN OF MRF AND ETA-XX BUILDING RIDGE IN AT SURFACE AND ALOFT FOR MONDAY SETTING STAGE FOR DRY DAY. AS HIGH PULLS OFF TO THE EAST ON TUESDAY...GULF OPENS UP AND WAA PATTERN PUMPS PROGRESSIVELY MOIST AIR INTO CWA. LOW PRESSURE DEVELOPS OVER SOUTHERN PLAINS AND TRACKS ACROSS CWA ON WEDNESDAY. WITH WARM FRONT PROGGED TO THE NORTH OF CWA...ALL PRECIPITATION SHOULD BE RAIN. GIVEN EXTENDED NATURE OF FORECAST WILL CARRY CHANCE OF RAIN FOR TUESDAY AND WEDNESDAY. TEMPERATURES THROUGH THE PERIOD TO REMAIN 10 TO 20 DEGREES ABOVE NORMAL. .DTX...NONE. OKEEFE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1110 AM EST WED FEB 23 2000 FORECAST PROBLEMS THIS AFTERNOON ARE DENSE FOG/POPS/TEMPS ACROSS EASTERN UPPER MICHIGAN...AND CLOUDS/POPS/TEMPS ACROSS NORTHERN LOWER MICHIGAN. VISIBILITY HAS STARTED TO INCREASE AT SOME LOCATIONS IN THE EASTERN UP. WILL NEED TO CONTINUE MENTION AREAS OF DENSE FOG THROUGH EARLY AFTERNOON...BUT SHOULD BE ABLE TO DISCONTINUE DENSE FOG ADVISORY AT FORECAST ISSUANCE TIME. MEANWHILE...SCATTERED RAIN SHOWERS ARE PUSHING THROUGH THE FORECAST AREA. SHOWERS HAVE DEVELOPED DUE TO PERSISTENT ISENTROPIC LIFT AND DECENT ELEVATED INSTABILITY...12Z KAPX 700-500 MB LAPSE RATE WAS ALMOST 8C/KM. HOWEVER...12Z KAPX SOUNDING WAS QUITE DRY...AND PER 88-D CROSS SECTIONS MOST OF THE PRECIPITATION WAS NOT REACHING THE GROUND. HOWEVER...RADAR RETURNS HAD INTENSIFIED DURING THE PAST 30 MINUTES. FARTHER WEST...SHOWERS WERE MORE WIDESPREAD ACROSS EASTERN WISCONSIN/WESTERN LAKE MICHIGAN WHERE MOISTURE WAS SOMEWHAT DEEPER AND MID/UPPER LEVEL DIVERGENCE WAS EVIDENT ON 12Z UPPER AIR ANALYSIS. THESE SHOWERS WERE HEADED TOWARD THE EASTERN UP. 12Z ETA/RUC DATA SUGGEST THAT MOIST AXIS WILL LIFT TOWARD NORTHERN COUNTIES OF THE FORECAST AREA THIS AFTERNOON. PER RADAR TRENDS AND MODEL FORECASTS...WILL ADD SCATTERED SHOWERS TO THE NORTHERN THIRD OF THE FORECAST AREA THIS AFTERNOON. MEANWHILE...ALTHOUGH MID LEVEL LAPSE RATES ARE FORECAST TO DECREASE SOMEWHAT BY 0Z...CANNOT RULE OUT A RUMBLE OF THUNDER ANYWHERE WITHIN MOIST AXIS...AND WILL ADD MENTION OF THUNDER AS WELL. ACROSS THE SOUTH...WILL CARRY EARLY SPRINKLES ACROSS THE SOUTHEAST. OTHERWISE...SATELLITE TRENDS SUGGEST THAT SUNSHINE WILL INCREASE ACROSS THE SOUTH...AND TEMPERATURES WILL PUSH WELL INTO THE 50S... MOST LIKELY BELOW RECORD HIGHS. .APX...NONE. ROWLEY mi SOUTHWEST ARIZONA/SOUTHEAST CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 245 AM MST THU FEB 24 2000 .SYNOPSIS... A LOW PRESSURE SYSTEM AND COLD FRONT WILL MOVE QUICKLY THROUGH THE STATE TODAY. THE MOISTURE REMAINS RATHER LIMITED WITH THIS SYSTEM AND TEMPERATURES SHOULD STAY BELOW NORMAL INTO FRIDAY. A LARGE HIGH PRESSURE SYSTEM WILL BRING WARMER WEATHER FOR THE WEEKEND. ANOTHER PACIFIC STORM SYSTEM WILL BRING MORE CLOUDS AND A CHANCE OF SHOWERS TO THE AREA ON MONDAY. .DISCUSSION... IMPRESSIVE CLOUD SHIELD ACROSS MOST OF AZ LAST NIGHT IN ADVANCE OF MODERATE TO STRONG SHORT WAVE. LOCATION OF PRIMARY VORT MAX ANALYZED BEST BY RUC AND ETA...ALTHOUGH MODELS IN FAIR AGREEMENT WITH HEIGHTS AND RH PATTERNS. INTERESTING 500-300MB HEIGHT FALLS FROM 00Z...CORE OF MAX FALLS TO OUR NORTH...NOT ALL THAT SURPRISING. BEST AREA FOR MODERATE PRECIP FROM ABOUT KIGM TO KGCN AND 4 CRNRS. TO THE SOUTH...COLD FRONT WAS ANALYZED NEAR YUMA AND MOVING EAST AS CLOUD BAND AND NARROW PRECIPITATION BAND HAD DEVELOPED ABOUT AS FCST. LIGHT SHOWERS TO CONTINUE WITH FRONT THIS MRNG...AND MODEL ESTIMATES APPEAR TOO HIGH AT THIS TIME. WILL KEEP CHANCES INTACT FOR METRO PHX AND DOWNGRADE GLOBE POPS AND THE REST OF AZZ024 FOR TODAY. MOISTURE TO SLOWLY DECREASE...BUT SC AND CU CLOUDS TO REMAIN IN PLACE WITH GOOD COLD ADVECTION. TEMPS TO STAY IN THE 60S IN YUMA AND PHX TODAY. BROAD UPR RIDGE TO SLOWLY DRIFT EAST...BUT TEMPS TO REBOUND SLOWLY. LONGER RANGE TRENDS POINT TO ANOTHER TROUGH PASSAGE FOR MONDAY BUT HEIGHTS ON NEW MRF ARE HIGHER THAN PREV 2 RUNS. SIPPLE N az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 300 AM CST THU FEB 24 2000 ...SHORT TERM... WATER VAPOR AND PROFILER DATA SHOW A VERY MATURE SHORTWAVE MOVING THORUGH WESTERN IOWA. A LLJ OF 40-50 KNOTS RUNS FROM ARKANSAS INTO SOUTHERN LAKE MICHIGAN. ANOTHER SHORTWAVE WAS MOVING THROUGH COLORADO WHILE THE NEXT BIG SYSTEM IS COMING ON SHORE IN CALIFORNIA. PLENTY OF JET ENERGY IS ASSOCIATED WITH THE CALIFORNIA SYSTEM WITH 150-160 KNOTS AT 250 MB JUST OFF SHORE WITH AN AIRCRAFT REPORT OF 175 KNOTS. IR SHOWS CLOUD TOPS HAVE COOLED WITH THE AREA OF SHRA/TSRA IN THE SOUTHERN PART OF THE FORECAST AREA. PER THE RUC THIS AREA OF PRECIPITATION IS ASSOCIATED WITH A COMBINATION UPPER TROF/850 MB WIND MAX. RADAR MOSAIC SHOWS A NARROW BAND OF SHRA/TSRA OVER THE NORTH PART OF THE FORECAST AREA MOVING INTO WISCONSIN AHEAD OF THE MAIN PRECIP AREA. 06Z SURFACE ANALYSIS HAS THE LOW BETWEEN KCSQ AND KICL WITH AN OCCUDED FRONT RUNNING TO KIRK. A WARM FRONT THEN RUNS INTO SOUTHERN ILLINOIS WITH THE COLD FRONT EXTENDING INTO NORTHWEST ARKANSAS. MOISTURE ANALYSIS HAS 40 DEW POINTS OVER THE IMMEDIATE AREA WITH 50 DEW POINTS JUST SOUTH OF THE FORECAST AREA. DEW POINTS IN THE 60S ARE AS NEARBY AS KMEM. PROBLEMS THIS PACKAGE ARE PRECIP TIMING...THEN CLOUDS/TEMPERATURES. 00Z MODELS APPEAR TO HAVE INITIALIZED OK BUT NONE OF THE MODELS WERE CATCHING THE 60 DEW POINTS AS FAR NORTH AS KMEM AT 06Z. AVN/ETA HAD BETTER POSITION OF THE MAIN FEATURES AT 06Z BUT WERE ON THE WEAK SIDE (3-4 MB) FOR THE CENTRAL PRESSURE OF THE LOW IN IOWA. AVN/ETA HAVE SLIGHTLY BETTER RUN TO RUN CONTINUITY THAN THE NGM AND THUS WILL BE FOLLOWED. CURRENT TREND OF THE MODELS LATELY HAVE BEEN TO UNDERESTIMATE THE STRENGTH OF THE SOUTHERN STREAM SYSTEMS AND ALSO BE A TAD FAR NORTH AND WEST. AVN/ETA/RUC SHOW CURRENT PRECIP SUPPORTED BY A SHORTWAVE TO EXIT MOST IF NOT ALL THE AREA BY 18Z. CONDENSATION PRESSURE DEFICITS INDICATE PRECIP IS IN THE 30-40 MB OR LESS AREA AND OTHER THAN PERHAPS FAR NORTHWEST ILLINOIS MOST OF THE FORECAST ARE TO BE DRY AFTER 18Z. DRY CONDITIONS THIS AFTERNOON AND MOST OF TONIGHT. LLJ SHIFTS INTO IOWA WITH QG FORCING AND CONDENSATION PRESSURE DEFICITS LOWERING IN THE 850-700 MB LEVEL. THIS SUGGESTS ELEVATED CONVECTION DEVELOPING TONIGHT. ETA HAS THIS SWEEPING THROUGH MOST OF THE AREA BY 12Z FRIDAY WITH AVN HAVING IT JUST REACHING THE AREA BY 12Z. THUS AN PERIOD OF PRECIP VERY LATE TONIGHT AND INTO FRIDAY MORNING APPEARS LIKELY...MAINLY ALONG AND WEST OF THE MISSISSIPPI. MAIN EVENT THEN SETS UP FOR LATE FRIDAY AFTERNOON/NIGHT PERIOD. STRONG DYNAMICS SETS UP WITH A LLJ OF AT LEAST 50 KNOTS OVER THE AREA BY 00Z SATURDAY. ALL MODELS AGREE ON THIS WHICH IS SCARY... SINCE THEY USUALLY DON/T DO THIS. STRONG QG FORCING AND LOWERED CONDENSATION PRESSURE DEFICITS TO MOVE INTO THE AREA LATE FRIDAY AFTERNOON AND MOVE THROUGH MOST OF THE FORECAST AREA BY 06Z SATURDAY. SOUNDING PROFILES SHOW SSE QUICKLY TURNING TO SSW NOT FAR OFF THE SURFACE AND THEN BEING UNIDIRECTIONAL THE REST OF THE WAY UP WITH 40 KNOTS JUST OFF THE SURFACE. THUS A SQUALL LINE SHOULD DEVELOP AHEAD OF THE FRONT AND THE SITUATION WOULD SUGGEST A LOW TOPPED SQUALL LINE. POTENTIAL DOES INDEED EXIST FOR POTENTIAL SEVERE...WITH THE MAIN THREAT BEING HAIL/WINDS. FWC/FAN NUMBERS ARE REASONABLY CLOSE EARLY ON BUT THEN DIGRESS. GIVEN CURRENT TEMPERATURES MAXES FOR TODAY LOOK LOW. FAN NUMBERS PREFERRED ON FRIDAY FOR MAXES. ...EXTENDED... DUE TO RUNNING LATE WON/T CHANGE THE EXTENDED BUT BASED ON NEW AVN THERE MAY BE A CHANCE OF PRECIP SATURDAY IN THE COMMA HEAD OF THE FRIDAY STORM SYSTEM. COORDINATED WITH DSM...LSE...CHI...ILX...STL...AND SPC. ZONES TO BE LATE BUT SHOULD BE OUT BY 400 AM. .DVN...NONE. NC il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 325 AM EST THU FEB 24 2000 ...SHOWERS TODAY THEN BREEZY AND WARMER FRIDAY... SEEMS LIKE THE WEATHER HAS GONE INTO SPRING MODE. THE 160 TO 180 KT JET COMING ACROSS THE PAC NEAR 45N 140W AT 00Z THIS EVENING WILL SURELY DIG THE NEXT UP STREAM WAVE COMING ON SHORE OVER CA TODAY. THIS IS SHEARING OUT THE WAVE OVER IA (24/00Z) AS THAT IF FORCED TO MOVE THROUGH THE UPPER RIDGE. THIS WILL BRING AN AREA OF SHWRS AND TSTMS OVER SRN WI/IL INTO MI BY 12Z AND MOVE ACROSS THE CWA DURING THE DAY. THE RUC AND ETA SHOW INCREASED 850 THTE CONVERGENCE JUST AHEAD OF THE PCPN AREA BTW 06Z AND 12Z... THEN WEAKEN THE CONVERGENCE AREA AS IT CONTINUES TO MOVE TO THE EAST NORTHEAST DURING THE DAY TODAY. THERE IS ASSOC UPPER DIVERGENCE...TOTAL TOTALS ARE FCST TO BE IN THE LOWER TO MID 50S OVER SRN LWR MI AS THIS MOVES THROUGH WITH 850 TO 500 LAPSE RATES BTW 6.5 AND 7 F. 850 DWPTS WILL BE NEAR 5C AND SFC DWPTS WILL BE NEAR 50. THUS SHOULD BE LITTLE PROBLEM GETTING SCT THUNDERSTORMS OVER THE SRN CWA TODAY. WILL HAVE CHC OF TSTM NRN CWA FOR TODAY TO SUGGEST STRONGEST CONVECTION OVER THE SRN 1/3 OF CWA. TONIGHT THAT SYSTEM MOVES OUT AND A SMALL POCKET OF COOL AIR SETTLES OVER THE AREA. WITH SFC LOW WEAKENING AND MOVING EWD OVER CWA TONIGHT EXPECT SHOWERS TO END THIS EVENING THEN FOG TO DEVELOPED OVERNIGHT AS MID LEVEL CLOUDS MOVE OUT. LEAVING WET GROUND WITH LIGHT WINDS. FRIDAY...NEXT SYSTEM APPROACHES FROM THE WEST. WITH THE 180 KT JET FCST BY THE ETA TO DIVE INTO THAT SYSTEM... IT WILL SURELY DEEPEN NICELY... MAYBE MORE THAN FCST BUT THE CURRENT MODELS ALL AGREE ENOUGH SO AS TO NOT MAKE A DIFFENCE IN THE FCST HERE FOR FRIDAY. WARM FRONT WILL LIFT NWD ACROSS CWA DURING THE MORNING. THAT WILL LIFT LOW ST CLDS AND FOG AND REPLACE WITH WITH A FAIR AMOUNT OF SUN THROUGH SOME PATCHY LAYER HIGH BASED AC AND CI. USING THE 1000/925 THICKNESS TOOL CREATED AT GRR... HIGHS SHOULD APPROACH 65 TO 70 FRIDAY. THAT IS AT LEST 10F ABOVE MOS. THIS IS OK SINCE THE MODELS HAD THE SAME PROBLEM TODAY WITH UNDER FORECASTING THE HIGH TEMP. SAME TOOL USED MONDAY MORNING FCST HIGHS NEAR 60 FOR WED. THIS WOULD GIVE RECORD TEMPS TO MOST OF AREA... SINCE THIS TOOL HAS BEEN WORKING VERY VERY VERY NICELY... WILL GO WITH IT. ZONES BY 400 AM. WDM EXTENDED FORECAST DISCUSSION... MINOR CHANGES TO EXTENDED FORECAST THIS MORNING...WITH REGARDS TO TIMING OF PCPN AND TEMPERATURES FOR FRI NIGHT AND SATURDAY. 00Z MODEL RUNS SUGGEST A LATER ARRIVAL OF SHOWERS/THUNDER WITH THE NEXT STRONG SPRING-LIKE SYSTEM TO AFFECT THE GREAT LAKES. WITH A 180KT JET DIVING INTO THE BACK-SIDE OF THE TROUGH NOW MOVING ONSHORE ALONG THE WEST COAST...SYSTEM LIKELY TO BE STRONGER AND ARRIVE LATER THAN THE PREV MEDIUM RANGE MODEL RUNS HAD SUGGESTED. WITH TEMPS EXPECTED TO RISE WELL INTO THE 60S ON FRIDAY...STRONG SRLY WINDS WILL NOT ALLOW TEMPS TO FALL BELOW 50 DEGREES FRI NIGHT. LITTLE RISE EXPECTED SAT AS SHOWERS/THUNDER LIKELY DURING THE DAY. MUCH COOLER WEATHER BEHIND THIS STRONG SYSTEM FOR SUN AND MON. 00Z CANADIAN SUGGESTS POTENTIAL FOR WRAP-AROUND MOISTURE...WITH RAIN/SNOW SHOWER POTENTIAL ON SUN...AND COLDER TEMPS THAN CURRENTLY FORECASTED. WILL LEAVE FORECAST DRY WITH TEMPS AS IS FOR NOW. LATER MODEL RUNS SHOULD HAVE A BETTER HANDLE ON THE COLDER AIR AND MOISTURE DISTRIBUTION BEHIND THE SYSTEM. GREENE .GRR...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 320 PM CST WED FEB 23 2000 SYNOPSIS: WARM AND WINDY SPRING WEATHER WILL CONTINUE TO HAVE A FIRM GRIP ON THE FORECAST AREA THROUGH FRIDAY. THE 500 MB LOW IN THE CENTRAL PLAINS WILL MOVE TOWARD THE NORTH NORTHEAST AND FILL AS IT MOVES INTO IOWA. THE ASSOCIATED SURFACE FRONT WILL STALL WEST OF THE FA AS THE SURFACE LOW ALSO MOVES INTO IOWA AND DISSIPATES. ANOTHER STRONG TROUGH WILL MOVE EASTWARD ACROSS THE SOUTHWESTERN U.S. AND ANOTHER CLOSED LOW IS EXPECTED TO DEVELOP EAST OF THE ROCKIES ON THURSDAY AND MOVE NORTHEASTWARD INTO MINNESOTA BY SATURDAY. A SURFACE LOW WILL ALSO MOVE INTO MINNESOTA BY SATURDAY WITH A FRONTAL SYSTEM SOUTHWARD INTO ARKANSAS AND LOUISIANA. AHEAD OF THIS FRONTAL SYSTEM...WIDESPREAD RAINS ARE EXPECTED TO OCCUR WITH A CHANCE OF RAIN IN EXTREME WESTERN PORTIONS OF THE FA BY LATE FRIDAY NIGHT. THE NGM...AVN...AND ETA ARE IN PRETTY GOOD AGREEMENT THROUGH FRIDAY AT 12Z FOR THE NEXT DEVELOPING 500 MB LOW, BUT THE ETA PREDICTS A SLIGHTLY WEAKER LOW THAN THE THE NGM AND AVN MODELS. THE STRONGER 500 MB LOW FORECAST BY THE NGM AND AVN MODELS IS THE FAVORED SOLUTION SINCE THE ETA HAS TENDED TO BE TOO WEAK FOR THE 500 MB LOW FORECAST IN RECENT SIMILAR SOUTHERN STREAM SYSTEMS. IN THE SHORT TERM...THE 19Z FORECAST RUC SOUNDING FOR NORTHWESTERN PORTIONS OF THE FA(WITH SLIGHT MODIFICATION FOR HIGHER LOW LEVEL MOISTURE) STILL SHOWS 0-3 KM HELICITY AND CAPE COMBINATION THAT IS FAVORABLE FOR SEVERE SUPERCELLS. (FORECAST VALUES OF 339 M2/S2 AND 1246 J/KG RESPECTIVELY) HOWEVER...NO STRONG "TRIGGER" IS AVAILABLE IN OUR FORECAST AREA TO GET THE STORMS GOING THIS EVENING. THE CLOSEST CONVECTION TO OUR FA AS OF 300 PM LOCAL IS IN NORTH CENTRAL LOUISIANA AND IN SOUTHEASTERN ARKANSAS WEST OF THE MISSISSIPPI RIVER. WILL KEEP SLIGHT CHANCE POPS FOR THIS EVENING IN EXTREME NORTHWESTERN ZONES AND WILL LEAVE POPS OUT FOR TONIGHT EVERYWHERE ELSE. FOR THURSDAY AND FRIDAY...TIGHT SURFACE GRADIENT WILL BE IN PLACE BETWEEN HIGH OFF THE NORTH CAROLINA COAST AND THE NEXT SURFACE LOW THAT WILL DEVELOP EAST OF THE ROCKIES. TEMPERATURES SHOULD REMAIN UNSEASONABLY WARM THROUGH FRIDAY. EXPECT ENOUGH BREAKS IN THE CLOUDS THURSDAY AND FRIDAY TO ALLOW TEMPERATURES TO REACH WELL INTO THE 70S AND POSSIBLY LOW 80S IN SOME LOCATIONS. QPF DISCUSSION: WITH ONLY SLIGHT CHANCE POPS FOR ISOLATED STORMS IN NORTHWESTERN ZONES THIS EVENING DO NOT EXPECT HIGH ENOUGH BASIN AVERAGE PRECIP FOR SIGNIFICANT QPF. IN THE EXTENDED...SOUTHERN PORTION OF ANOTHER FRONTAL SYSTEM SHOULD PUSH ACROSS THE FA ON SATURDAY AND WILL BRING ANOTHER CHANCE OF RAIN. EXPECT ONLY SLIGHT COOLING AND DRIER AIR BEHIND THE FRONT FOR SUNDAY AND MONDAY. PRELIM NUMBERS: JAN 059/080 059/077 -00- MEI 058/080 058/079 -00- .JAN... MS...NONE. AR...NONE. LA...NONE. 15 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1144 PM CST WED FEB 23 2000 LOW CLOUDS FORMING OVER THE HILL COUNTRY SPREADING NORTHWEST TODAY FORECAST AREA. LATEST RUC AND ETA MODELS BRING LOW CLOUDS AS FAR AS CONCHO VALLEY BY SUNRISE. WINDS LIKELY TO INCREASE AS LOW CLOUDS ARRIVE DUE TO BETTER CONDITIONS FOR MIXING. WILL UPDATE ZONES FOR INCREASED CLOUDS AND WINDS... MAINLY FROM THE CONCHO VALLEY SOUTH AND EAST. 12 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 336 AM CST THU FEB 24 2000 MAIN FORECAST PROBLEM IS CURRENT PRECIPIATION TODAY AND NEXT SYSTEM FOR THURSDAY LATE NIGHT AND FRIDAY. CURRENT WATER VAPOR IMAGERY INDICATES THE BEST SHORTWAVE DYNAMICS ASSOCIATED WITH BROAD LOW OVER UPPER MISSISSIPPI RIVER VALLEY IS OVER KMLI AS OF 09Z. 00Z ETA AND LATEST RUC MODELS HAVE THIS REGION OF QVECTOR CONVERGENCE DEPICTED WELL AND THIS MATCHES RAIN REGION ACROSS NORTHERN IL AND EASTERN IA. THIS AREA WILL MOVE NORTHEAST TODAY AND PRDUCE THE BEST CHANCE OF RAIN SOUTH OF A KDLL- KLSE-KALO LINE. 00Z MODELS ARE IN FAIRLY GOOD AGREEMENT ON SYNOPTIC SCALE VARIABLES IN THE NEXT STRONG LEE CYCLOGENESIS WAVE IN THE PLAINS. THIS SHORTWAVE IS NOW OVER SRN CA MOVING EAST. 00Z MODELS STRENGTHEN A LEE LOW OVER SOUTH DAKOTA BY FRIDAY EVE...WITH AVN/ETA SOLUTION FURTHEST SOUTH. AHEAD OF THIS ENERGY...SOUTHERLY FLOW AND AN INTENSE LOW LEVEL JET ADVECT MAJOR MOISTURE NORTHWARD AND BY LATE THURSDAY NIGHT ELEVATED CONVECTIVE FORCING IS IN PLACE OVER IOWA. LOW LEVEL SPEED CONVERGENCE OF 60KTS TO 20 KTS FROM SOUTH OF KDSM-KLSE WITH 10C DEWPOINTS AT 850 MB LEADS ME TO THINK WE WILL SEE A GOOD CHANCE OF RETURN FLOW ELEVATED CONVECTION FRIDAY MORNING...FOLLOWED BY A BREAK UNTIL UPPER LEVEL DYNAMICS AND COLD FRONT MOVE THROUGH LATER FRIDAY. MODEL CONVECTIVE SCHEMES HAVE TROUBLE TRIGGERING ELEVATED CONVECTION. WILL KEEP A CHANCE LATE THURDAY NIGHT WESTERN AND SOUTHERN PORTIONS...THEN AREAWIDE FRIDAY WILL KEEP LIKELY WORDING...THIS LOOKS GOOD. SURFACE INSTABILITY WILL BE PRESENT FOR THUNDER ACROSS SOUTHERN FORECAST AREA FRIDAY AND FRIDAY NIGHT WHEN MODERATE QG FORCING MOVES IN. SOUTHWEST FORECAST AREA IS IN SPCS SLIGHT RISK FOR FRIDAY AND THAT LOOKS GOOD EVEN WITH UNIDIRECTIONAL SHEAR. MOST OF THE SIGNIFICANT QG FORCING SHOULD REMAIN NORTH OF INSTABILITY. HAIL...AND WIND THE MAIN THREATS. FRIDAY COULD BE A RECORD WARM DAY BASED ON HOW WARM FRONT MOVES THROUGH AND HOW FAR NORTH IT MOVES. HAVE TRENDED TOWARD WARMER AVN GUIDANCE NUMBERS AND BUMPED FRIDAYS HIGHS 1 CATEGORY AS A TREND. COORD W/MPX..DVN..DMX .LSE...NONE. DB wi WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 344 AM MST THU FEB 24 2000 STORM MOVING THROUGH UT AND AZ SHOWING CONFLICTING DEVELOPMENTS SOME OF WHICH SUPPORT MORE SNOW OVER SWRN CO OTHER SUPPORT LESS. WILL STAY THE COURSE WITH CURRENT SNOW AND BLOWING SNOW ADVY FOR CO CNTRL AND SW MTNS AND UT'S LA SAL AND ABAJO MTNS. SATELLITE IMAGERY AND RUC/MESO ETA TROP PRES/PV AND VORT FIELDS SHOW ANOTHER IMPULSE DROPPING INTO THE BOTTOM OF THE TROUGH ALONG THE SRN CA COAST. IT APPEARS THIS WILL ENCOURAGE A BIT MORE SPLITTING OF THE TROUGH WITH TIME AND TAKE SOME DYNAMIC LIFT TO SOUTH. AT SAME TIME THIS IS SLOWING EASTWARD PROGRESSION OF THE TROUGH WHICH MAY KEEP MOIST SWLY FLOW OVER SAN JUAN FOR LONGER PERIOD TDA AND TNGT. FORECAST SOUNDING AND TIME-HEIGHTS SHOW GOOD MOISTURE AND INSTABILITY ...BUT SWLY WINDS DECREASE SIGNIFICANTLY AFTER 18Z TDA. MORE THAN ANYTHING THIS IS WHAT COMPELLED ME TO LEAVE THE ADVISORIES AS THEY ARE AND NOT UPGRADE TO A WARNING. WITH SLOWER MOVEMENT FRONT MAY NOT PASS GJT UNTIL CLOSE TO 06Z TNGT. INSTABILITY STILL GOOD ENOUGH FOR MENTION OF TSTMS THIS AFTERNOON AND EVENING. MODELS HOLD OFF GRADUAL SHIFT TO W THEN NW FLOW ALOFT UNTIL ABOUT 06Z. SNOW IN S WILL DECREASE THEREAFTER BUT THEN INCREASE ACROSS CNTRL AND NRN PORTIONS OF CWA. FRI WILL DECREASING PCPN ACROSS THE AREA. NO CHANGES TO EXTENDED AS MIDRANGE MODELS KEEPING TROUGHY PATTERN IN PLACE. CUOCO .GJT...SNOW AND BLOWING SNOW ADVISORY TDA AND TNGT CO SW AND CNTRL MTNS AND SE UT MTNS...UTZ28 (MTNS)...COZ009/010/012/018/019. co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1120 AM EST THU FEB 24 2000 WILL UPDATE ZONES FOR POPS THIS AFTERNOON. 88D TRENDS INDICATE THAT PRECIP WILL BE ROTATING ACROSS NORTHERN PORTION OF CWA THROUGH THE AFTERNOON...WITH ONLY SCATTERED ACTIVITY FOUND ACROSS THE SOUTH. AS SURFACE WARM FRONT DRIFTS NORTH...SO TOO WILL FOCUSING MECHANISM. STILL HAVE TO DEAL WITH WEAKENING UPPER LEVEL WAVE CROSSING CWA DURING AFTERNOON/EVENING. THEREFORE...PLAN TO GO WITH SCATTERED SHOWERS FOR SOUTHERN HALF OF CWA...AND CATEGORICAL WORDING FOR NORTHERN HALF OF CWA...TRENDING TO SCT SHOWERS LATER. WILL CONTINUE WITH RUMBLE OF THUNDER. RUC AND MESO-ETA INDICATE SOME POTENTIAL FOR ELEVATED CONVECTION THIS AFTERNOON. RUC EVEN SUGGESTS SURFACE LI/S TO SLIP BELOW ZERO ACROSS FAR SOUTHEAST AROUND 00Z. A QUICK PEEK AT NEW ETA SHOWS A HINT OF SOME SURFACE BASED INSTABILITY NICKING THE SOUTHERN CWA AROUND 00Z. WITH THIS IN MIND...WILL ADD MENTION OF A RUMBLE OF THUNDER TO EARLY EVENING FORECAST. WILL ALSO WIDEN AFTERNOON TEMPERATURES TO THE LOW SIDE FOR POINTS FROM FNT NORTH. .DTX...NONE. OKEEFE mi DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 955 AM CST THU FEB 24 2000 BIG STORY TODAY WILL BE THE WINDS. SURFACE LOW WILL CONTINUE TO DEEPEN THIS AFTERNOON AND TONIGHT WITH STRONGEST LOW LEVEL JET AND LOWER TROPOSPHERIC GRADIENT PROGGED BETWEEN 00Z AND 12Z. KBRO VAD WIND PROFILER SHOWS WINDS IN THE 30 TO 35 KNOT RANGE BETWEEN 1 TO 5 KFT WITH SURFACE WINDS ALREADY GUSTING BETWEEN 25 AND 30 KNOTS THIS MORNING. SO WIND ADVISORY DEFINITELY ON TRACK. WITH MESO-ETA SHOWING WINDS IN THE 925 MB LAYER INCREASING FROM 30+ KNOTS TO AROUND 50 KNOTS BY AFTERNOON AND WITH SFC GRADIENT INCREASING FURTHER FROM AN ALREADY INCREDIBLE 16 MB BETWEEN THE PANHANDLE AND THE WESTERN GULF PER MSAS TO AROUND 18 MB THIS AFTERNOON PER RUC/MESOETA. WILL OBVIOUSLY MAINTAIN WIND ADVISORY TODAY...BUT WILL BEEF UP THE WINDS. WAS CONTEMPLATING HIGH WIND WATCH FOR THE FORECAST AREA...BUT FOR NOW WILL GO WITH HIGH CATEGORY WIND ADVISORY AT THIS TIME. MAY NEED TO COME BACK TO THIS CONTEMPLATION BEFORE NOON. WINDS SHOULD NOT DECOUPLE ALL THAT MUCH TONIGHT...SO WIND ADVISORY WILL CONTINUE THIS EVENING...AND POSSIBLY OVERNIGHT. PER LATEST VISIBLE SATELLITE IMAGERY LOW LEVEL CLOUD COVER EXTENDS OVER MOST OF THE FORECAST AREA WITH MOST OF THE OUTER WATERS CLOUD FREE. LOW CLOUDS UPSTREAM OVER THE MEXICAN STATE OF TAMAULIPAS ARE RATHER PATCHY. SO PARTLY SUNNY SKIES OVER THE AREA LOOKS ON TRACK. MARINE...WITH WINDS FORECAST TO INCREASE OVER A LARGER FETCH WILL KEEP SCA GOING THROUGH TONIGHT AND PROBABLY CONTINUING INTO FRIDAY. SYNOPTIC...CORDERO (64) MESO...WIGGINTON (56) HMT...WATKINS .BRO...SCA FOR GMZ130-150-155-170-175. WIND ADVISORY FOR TXZ248>255. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIDLAND TX 739 AM CST THU FEB 24 2000 LOW CLOUDS PUSHING NW-N INTO ERN CWFA. HAVE SENT UPDATE TO INCLUDE MORNING CLOUDS. OTHERWISE RUC HOLDING LOW LEVEL MSTR IN ACROSS NERN CWFA THIS AFTERNOON. PREVIOUS THOUGHTS FOR SEVERE A FEW SEVERE NE STILL LOOK GOOD. .MAF... TX...NONE NM...NONE GPM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 900 PM EST WED FEB 23 2000 STORM SYS TO MOVE ACRS UPR MS RIVER VLY TONITE AND INTO THE GREAT LKS REGION ON THU. A WK FRONTAL BOUNDARY TO GRADUALLY DROP DOWN ACRS THE FA FROM CANADA TONITE AND ON THU. SFC PRESS GRADIENT TO RELAX ACRS THE FA OVRNITE TONITE. 18Z 40KM RUC (NO 00Z OR 21Z RUN AVAILABLE IN N-AWIPS HERE AT BTV) SHOWS W-SW SFC WINDS DECREASING THROUGHOUT THE EVENING WITH TEMPS GETTING DOWN INTO THE M30S-L40S BY 06Z. BEST H85 MOISTURE TO BE LOCATED ACRS SRN VT AND THE ADIRONDACKS OVRNITE. RUC JUST SHOWS SOME VERY -RA (BARELY MEASURABLE) TO OCCUR ACRS THESE TWO AREAS THRU 06Z. UPR LVL RIDGE TO BE BUILDING ACRS THE GREAT LKS REGION OVRNITE TONITE AS WELL. 88D COMPOSITE/BUFCAN DATA SHOWS AN AREA OF RA MOVING ACRS WESTERN/CENTRAL NY STATE AND ONT ATTM. THIS AREA OF PCPN TO AFFECT THE ST LAW VLY/NORTHERN ADIRONDACKS BY AROUND 06Z...THE CHAMP VLY AND RUT CTY BY AROUND 09Z AND EASTERN VT AFTER THAT. THE TREND APPEARS FOR THIS AREA OF PCPN TO BE WEAKENING WITH TIME THOUGH. HAVE ADDED CHC OF A SPRINKLE AND/OR SHRA TO ALL ZONES OVRNITE. MOST OF THE FA TO BE UNDER WK H85 WAA THRU 00Z FRI (WITH WK CAA TAKING PLACE IN THE CT RIVER VLY AFTER 12Z THU). H85 MOISTURE TO LINGER AROUND THE FA IN THE VICINITY OF THE WK FRONTAL BOUNDARY ON THU. H85 TEMPS AND 925 MB WET-BULB TEMPS SHOW IT/LL BE PLENTY WARM FOR ANY PCPN TO FALL AS RA ON THU. INTERESTING SCENARIO FOR THU AS PW VALUES OF AROUND 0.75" WILL BE OVER THE FA AS AN UPR LVL RIDGE CRESTS OVER THE AREA AT THE SAME TIME. THESE CONFLICTING FACTORS PROLLY LEAD TO A LT QPF EVENT AT BEST AND HAVE ADDED MENTION OF SPRINKLES TO FORECAST (IN THE EASTERN PART OF THE FA) FOR THU. GOING FORECAST FOR BEST CHC FOR ANY MEASURABLE RA ON THU OCCURRING IN THE WESTERN ZONES STILL LOOKS GOOD FROM HERE. PATCHY FG A POSSIBILITY IN A FEW ZONES OVRNITE WITH SHRA MOVING THROUGH AND SNOWMELT MOISTURE LINGERING ON THE GROUND. HAVE ADDED THAT WORDING TO A FEW ZONES. HAVE TWEAKED OVRNITE TEMPS IN MOST ZONES BASED ON CURRENT OBS TRENDS. HYDRO-WISE...RIVERS EXPERIENCED SOME RISES DUE TO SNOWMELT BUT ARE STILL BEHAVING NICELY. WORK ZONES GONE. FINAL ZFP AFTER A FEW TWEAKS AND A QUICK LOOK AT THE LATEST LAMP DATA. .BTV....NONE. MURRAY vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 951 AM EST THU FEB 24 2000 HAVE MADE SOME ADJUSTMENTS TO THE PROBABILITIES IN THE SOUTHERN HALF OF THE FORECAST AREA. INCREASED THE PROBABILITIES THERE THIS AFTERNOON AS THE RUC SHOWS SOME WEAK DIVERGENCE ALOFT IN THAT AREA. OTHERWISE NO CHANGES. .RLX... WV...NONE. VA...NONE. KY...NONE. OH...NONE. wv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1150 AM CST THU FEB 24 2000 UPDATED ZNS TO LET DENSE FOG ADVY EXPIRE. VSBYS NOW AT LEAST SVRL MILES XCP FOR KMCW VCNTY AND SHOULD CONT TO RISE. ALSO MADE SOME MINOR ADJUSTMENTS TO WNDS AND RAISED TEMPS A CATEGORY TO FIT CURRENT TRENDS. DO XPC SOME BREAKS TO DVLP SRN SXNS LATE PER 15Z RUC...BUT HOPEFULLY LATE ENOUGH TO PRECLUDE MUCH OF A JUMP IN TEMPS. .DSM...NONE SMALL ia