AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 400 AM PST MON MAR 20 2000 LATEST RUC SOUNDINGS SHOW 140 KT NWLY JET MAX AT 350 MB OVER FCST AREA. MEANWHILE SAC PROFILER SHOWING INCREASING LOW LEVEL WINDS...OVER 50 KT AT 1500 FT...WITH MANY SURFACE OBS READING SUSTAINED WINDS OF 20 KT OR BETTER. SURFACE GRADIENT HAS RELAXED IN NORTHERN ZONES AS MOST PRESSURE RISES ARE NOW CENTERED EAST OF CWA IN GREAT BASIN AS POLAR AIR IS DRIVEN SOUTHEASTWARD BEHIND TODAYS FRONTAL PASSAGE. EVEN STRONGEST GRADIENT IN PLACE OVER CENTRAL- WESTERN ZONES HAVING TO BATTLE RADIATIVE INVERSION. GRADIENT OBVIOUSLY WINNING OUT TONIGHT...BUT SLIGHTLY LESS FAVORABLY ALIGNED UPPER LEVEL SUPPORT SHOULD GIVE WAY TO INVERSION TONIGHT AND ALLOW WIND ADVISORY TO EXPIRE. MODELS AGREE ON REPEAT OF ADVISORY LEVEL WINDS TUESDAY AFTERNOON AS AZ/NM CLOSED LOW RETROGRADES TO LOCATION OVER YUMA AZ SO THIS WILL HAVE TO BE WATCHED. THIS RETROGRESSION SOLUTION ALSO PUSHES BACK TIMING OF NEXT SHORTWAVE INTO NORTHERN ZONES TO THUNRSDAY NIGHT OR EARLY FRIDAY AS COMBO OF WEST-EAST RIDGE AXIS AND AZ LOW PROVIDES NICE BLOCKING PATTERN TO DEFLECT THURSDAY SHORTWAVE INTO OREGON. SJC .STO...WIND ADVISORY TODAY FOR THE MOUNTAINS OF LAKE COUNTY...THE INTERIOR MOUNTAINS AND FOOTHILLS OF NORTHERN CALIFORNIA...THE CENTRAL AND SOUTHERN SACRAMENTO VALLEY...THE DELTA...AND THE NORTHERN SAN JOAQUIN VALLEY. BLU NN 039/032 051/038 060 63000 RBL NN 063/042 071/038 079 63000 SAC NN 065/042 070/046 076 63000 ca SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 325 PM MST MON MAR 20 2000 WILL KEEP THIS RELATIVELY SHORT AS QUITE BUSY WITH NUMEROUS HIGHLIGHTS AND DEVELOPING WEATHER. MAIN CONCERN IS OF COURSE POTENTIAL SNOW STORM ON THIS FIRST DAY OF SPRING. CWFA CURRENTLY SEEING INCREASING CLOUDS AND SOME AREAS OF SNOW...FOR EXAMPLE THE WOLF CREEK PASS AREA HAS SEEN 7 INCHES OF SNOW FROM 7 AM MST. LATEST ETA HAS CLOSED UPPER LOW OVER WEST-CENTRAL ARIZONA AT 00Z TUESDAY AND ETA MOVES THIS UPPER LOW INTO CENTRAL AND SOUTHWEST ARIZONA THROUGH 12Z WEDNESDAY. ETA PROGS MAIN SURFACE LOW OVER NORTHWEST NEW MEXICO TONIGHT WHILE 700 LOW IS LOCATED OVER CENTRAL ARIZONA TONIGHT. ETA/MM5 GENERATES SEVERAL INCHES OF SNOW OVER LARGE AREAS OF SOUTHERN COLORADO TONIGHT INTO TUESDAY WITH SNOW DEVELOPING IN EARNEST AROUND TO A FEW HOURS AFTER 00Z TUESDAY. 21Z RUC NOT SO GENEROUS WITH SNOW AMOUNTS...HOWEVER DOES INDICATE SNOW INCREASING BY 09Z TUESDAY. ETA/MM5 INDICATES 700 MB WINDS AND MOISTURE PROFILE BECOMING MORE FAVORABLE FOR SNOW TONIGHT OVER LARGE SECTIONS OF THE CWFA. WILL ISSUE NUMEROUS HIGHLIGHTS...CONCERNING THIS DEVELOPING SITUATION... SEE BELOW. EXTENDED...ETA/AVN GENERALLY SUPPORTS UNSETTLED WEATHER INTO THURSDAY WITH AVN INDICATING POTENTIAL HYDROLOGICAL PROBLEMS FAR SOUTHEAST ZONES WEDNESDAY AFTERNOON INTO THURSDAY AS UPPER SYSTEM OVER ARIZONA PROJECTED TO MOVE TO NORTHEAST NEW MEXICO BY 12Z THURSDAY...WILL NEED TO MONITOR FAR SOUTHEAST CLOSELY NEXT FEW DAYS. WILL KEEP CWFA GENERALLY DRY FRIDAY AND SATURDAY AS REGION BETWEEN STORM SYSTEMS. .PUB...WINTER STORM WARNING TONIGHT AND TUESDAY FOR ZONES 60/61/65/66/67/68/70/71/72/74 AND 75. SNOW AND BLOWING SNOW ADVISORY TONIGHT AND TUESDAY FOR ZONES 58/62/63/64/73/76 AND 77. co EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 742 PM EST MON MAR 20 2000 WEAK COLD FRONT CURRENTLY ACROSS CENTRAL CWA AND MOVING SOUTH. 23Z RUC TAKES IT AND ASCD NW SFC WIND SHIFT THROUGH REMAINDER OF CWA BY 10 PM...WHICH MAY BE A BIT FAST. WINDS OVER INTERIOR HAVE ALREADY BECOME NW N OF KISSIMMEE TO THE CAPE. WITH NIGHTFALL ONSHORE COMPONENT HAS RELAXED AND SHOULD BECOME NW OVER ALL INTERIOR AREAS BY MIDNIGHT. RECENT MESOSCALE MODELS (RUC/MESOETA) AND SFC OBS ARE KEEPING S/SE WIND ALONG COASTAL AREAS...ESPECIALLY SOUTHERN SEGMENT AND MAY HAVE TO ADJUST COASTAL FORECAST SLIGHTLY TO ACCOUNT FOR THIS. OTHERWISE...ONLY MINOR CHANGES PLANNED. .MLB...FIRE WEATHER WATCH TUESDAY AFTERNOON FOR ORANGE...LAKE... SEMINOLE ...OSCEOLA...AND INTERIOR VOLUSIA COUNTIES. PENDERGRAST fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 858 PM EST MON MAR 20 2000 LTST SFC MAP SHOWS DECAYING AREA OF LOW PRES ACRS C IL UNDERNEATH VERTICALLY STACKED LOW. SAT IR LOOP SHOWING LITTLE MOVEMENT AS CIRC CONTS TO SPIRAL ACRS THE STATE. 00Z RUC MODEL HAS AN EXCELLENT HANDLE ON CURRENT OBS AREA OF PRECIP PER COMPOSITE RADAR INVOF SFC OCCLUSION EXTND FM NR VPZ SE TO ILN. PRECIP DVLPMNT TIED TO SIG MOIST CONV AT 925 MB LVL WHICH IS PROGGED TO CONT THRU 06Z BEFORE BEGINNING TO SHIFT EWD INTO OH. PERSISTENT AREA OF ENHANCED PRECIP NOTED NR MID LVL CIRC CNTR OVR THE LAST 3 HRS VCNTY OF MZZ WHICH IS TROUBLING GIVEN LOW FFG GUIDANCE THAT AREA. HWVR REPORTS TO THAT AREA INDICATE NO PROBLEMS YET. OTHERWISE GIVEN SLUGGISH MOVEMENT TO THIS SYS...XPC DZ AND FOG LTR TONIGHT W HALF BEHIND SFC OCCLUSION SIMILAR TO WHAT IS OCCURRING PRESENTLY FM S WI INTO N IL. ZONE UPDATE OUT TO ACCOMMODATE ABV THINKING. .IWX...NONE. TEH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND 859 PM MST MON MAR 20 2000 BASED ON SATELLITE IMAGERY...LATEST RUC2 RUNS...AND NEW ETA/NGM EACH SUGGEST THAT THERE WILL BE A WELL-DEFINED EAST EDGE TO THE PRECIP SHIELD THAT IS TO DEVELOP OVER THE WEST CENTRAL HIGH PLAINS OVERNIGHT. SO...I HAVE OPTED TO CUT POPS TONIGHT EAST OF A TRENTON NEB TO COLBY TO TRIBUNE LINE. SOME MINS TWEAKED A CATEGORY LOWER AS TEMPS HAVE ALREADY REACHED THE LOWER BOUND OF THE FORECASTED RANGE. .GLD...NONE. ENTWISTLE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 930 AM EST MON MAR 20 2000 SYNOPSIS: HIGH PRESSURE CENTERED OVER THE GULF OF ST LAWRENCE AND RIDGING SOUTHWARD ACROSS NEW ENGLAND WILL REMAIN NEARLY STATIONARY THROUGH TUESDAY. TECHNICAL DISCUSSION: HIGH PRESSURE CONTINUES TO REMAIN ANCHORED OVER THE GULF OF ST. LAWRENCE WITH RIDGING EXTENDING ACROSS NEW ENGLAND. AREA WEDGED IN-BETWEEN OCEAN GENERATED STRATUS CLDS TO THE SOUTH AND AC/CI CLDS ASSOCIATED WITH VORT MAX MOVING THROUGH EASTERN CANADA TO THE NORTH. CLOUDS FROM THE CANADIAN SYSTEM ARE SPILLING OVER THE UPPER LEVEL RIDGE AND ALLOWING SOME CLDS OVER THE CWA. EXPECT STRATUS DECK WHICH IS CLIPPING THE DOWNEAST COAST TO MOVE OFFSHORE THIS AFTN...AND THEN RETURN THIS EVE WITH THE MID AND UPPER LEVEL CLDS DIMMING THE SUN FROM TIME TO TIME OVER THE ENTIRE CWA. THUS THE PREVIOUS P/S FCST LOOKS GOOD. PREVIOUS TEMPS IN THE BALL-PARK...MAY NEED TO SHAVE A COUPLE OF DEGREES OFF TEMPS DOWNEAST. WILL LOOK AT 10 AM TEMPS BEFORE DECIDING. COASTAL WATERS: PERSISTENT NORTHEAST WINDS CONTINUE TO GENERATE SEAS IN EXCESS OF SMALL CRAFT ADVISORY LEVELS. WINDS ARE CURRENTLY BELOW SMALL CRAFT ADVISORY LEVELS...BUT (PER RUC WINDS) SHOULD INCREASE BACK TO SMALL CRAFT ADVISORY LEVELS DURING THE AFTERNOON. THUS...WILL MAINTAIN THE SMALL CRAFT ADVISORY. .CAR...SMALL CRAFT ADVISORY. LULOFS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 1005 AM EST MON MAR 20 2000 RAFL SPREADING NWD TWD CWFA...AND WL ARRIVE IN SWRN CNTIES BY NOON...ABT ON TIME. 06Z AND 12Z ETA CONTG TREND OF HVY PCPN CORE MVG ALNG BLURDG TNGT/TMRW. EACH RUN ADDS A CPL HNDTHS TO THE QPF. RUC A PINCH LESS AGRESSIVE IN AMTS...BUT ITS ONSET TIMING LOOKS GOOD. WL TWEAK WRDG FOR PCPN. DONT SEE TEMPS RISING TOO MUCH ABV LWR 40S SWRN HLF OF AREA GIVEN PCPN AND CRRNT DEWPTS AOB 40. AM CONCERNED ABT FLOOD POTL WRN CWA. WL REISSUE ESF...AND WL BEEF UP WORDING...STRESSING 6 HR AMTS GRTR THAN HLF INCH AND LOCTN IN VLLYS OF HILLY TRRN. THIS SUBJ WL BE REVISITED W/ AFTN PKG. .LWX...NONE. HTS md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 915 PM EST MON MAR 20 2000 FOG IS THE MAIN FCST CONCERN FOR THE OVERNIGHT. WV IMAGERY SHOWS UPPER TROF ACROSS THE OHIO VALLEY MOVING LITTLE. MOISTURE FEED CONTINUES FROM THE ATLANTIC TO THE GREAT LAKES REGION. REGIONAL RADARS SHOW PATCHES OF -RA ACROSS MI/WI DISSIPATING. MOST WIDESPREAD -RA HAD BEEN OVER CNTRL UPPER MI WHERE UPPER DIVG IN RIGHT ENTRANCE REGION OF WEAK UPPER JET STREAK EXTENDING FROM NW LK SUPERIOR TO S JAMES BAY WAS PROVIDING SOME LIFT. SFC OBS ACROSS FA SHOW WIDESPREAD FOG...BUT ONLY KCMX INDICATING DENSE FOG. FOG HAS NOT BECOME MUCH DENSER THIS EVENING. APPEARS WEAKLY DIVERGENT SFC FLOW AS SHOWN BY SFC OBS IS REASON FOR FOG NOT BECOMING MORE DENSE. LIGHT ENE FLOW IS SHOWN FROM KIMT TO KSAW WHILE LIGHT ESE TO SE FLOW SHOWN FROM KIWD TO KEWEENAW AND STANNARD ROCK. 00Z ETA/RUC SHOW BOUNDARY LAYER FLOW BECOMING SE ACROSS CNTRL FA OVERNIGHT...BUT GENERALLY REMAINING SLIGHTLY DIVERGENT. HOWEVER...SE FLOW WOULD CONTINUE TO BRING SLIGHTLY HIGHER DWPTS NW FROM LWR MI...AND FLOW WILL ALSO BE UPSLOPING INTO CNTRL FA. AT THIS POINT... BELIEVE IT IS STILL LIKELY THAT FOG WILL THICKEN OVERNIGHT OVER THE HIGHER TERRAIN OF CNTRL FA...AND WILL THUS LEAVE DENSE FOG ADVY IN PLACE. AS FOR PRECIP...MODELS SHOW WEAKENING UPPER JET STREAK FROM NW LK SUPERIOR TO JAMES BAY MOVING LITTLE OVERNIGHT. THIS WILL PROVIDE WEAK UPPER DIVG TO SUPPORT PATCHES OF SPRINKLES/-DZ. WITH SYSTEM CONTINUING TO WEAKEN AND WITH DRYING ALOFT...WILL MODIFY TUE FCST CNTRL/E ZONES TO DROP -RA CHC AND MENTION JUST SPRINKLES/DZ. CLOUDS/MOIST AIRMASS TO KEEP TEMPS STEADY OVERNIGHT. .MQT...DENSE FOG ADVY OVERNIGHT-EARLY TUE MIZ001-003>005-010>012. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 900 PM CST MON MAR 20 2000 FORECAST HAS BEEN UPDATED TO ELIMINATE MENTION OF PRECIPITATION. LATEST RUC MODEL KEEPS FORCING WITH SHORT WAVE TROUGH OVER ND...N OF AREA. NEW MODEL RUNS ALSO KEEP LOW LEVEL MOISTURE THROUGH AT LEAST 00Z ON WEDNESDAY. CLOUD COVER SHOULD RETARD RADIATIONAL FOG. .MSP...NONE. SCOTT mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1017 AM CST MON MAR 20 2000 HIGH PRESSURE RIDGING REMAINS OVER THE FORECAST AREA ALONG WITH INVERSION BETWEEN 925 AND 850 MB. LOW PRESSURE SYSTEMS CONTINUE TO THE NORTHWEST AND SOUTHEAST OF US. ENHANCED CLOUDINESS WITH DEFORMATION ZONE IS JUST TO THE EAST OF EAU WITH SOME DRIZZLE OCCURRING IN THE FAR EASTERN CWA. WILL KEEP THIS TREND GOING FOR THE AFTERNOON AS STACKED LOW PRESSURE SYSTEM WOBBLES AROUND NORTHERN IL THIS AFTERNOON. SOME CLEARING OCCURRED EARLY THIS MORNING FROM STC TO MAN BUT THIS HAS QUICKLY FILLED BACK IN. 12Z ETA/NGM IN AGREEMENT ON KEEPING ABUNDANT LOW LEVEL MOISTURE IN PLACE TODAY WHILE 15Z RUC IS TRYING TO DRY THINGS OUT IN WESTERN MN. KABR SOUNDING INDICATES LESS DEPTH TO THE LOW LEVEL MOISTURE BUT THE DAKOTAS ARE ALSO COVERED WITH PLENTY OF MID/HIGH LEVEL MOISTURE SO DON'T THINK TOO MUCH DISSIPATION OF THE LOW CLOUDS WILL OCCUR. THEREFORE WILL FOLLOW PERSISTENCE AND KEEP IT MAINLY CLOUDY. TEMPERATURES FOR THE AFTERNOON LOOK GOOD WITH AN EASTERLY WIND FLOW. .MSP...NONE. HILTBRAND mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 900 PM EST MON MAR 20 2000 EXPECT THE ISOLATED SHOWER IN LANCASTER COUNTY WILL DISSIPATE SOON DUE TO THE LOSS OF SURFACE HEATING. THE LATEST RUC ALSO SHOWED WEAK H5 PVA BECOMING NVA BY 02Z IN THE NE PART OF THE FORECAST AREA. HIGH LOW-LEVEL MOISTURE FROM TODAY/S HEAVY RAIN AND DRY AIR ALOFT COULD HELP SUPPORT FOG LATER TONIGHT. GUIDANCE KEEPS SOME WIND OVERNIGHT. THE RUC SHOWS 1000 MB NW WINDS OF 5 TO 10 KTS THROUGH 12Z WHICH COULD PREVENT FOG...BUT WINDS ARE CURRENTLY LIGHT WITH BROAD SURFACE LOW PRESSURE OVER THE AREA SO PLAN TO ADD PATCHY DENSE FOG TO TONIGHT/S FORECAST. NO OTHER CHANGES PLANNED. .CAE...NONE. RJL sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 855 PM CST MON MAR 20 2000 STRATUS STILL COVERING ERN TWO THIRDS OF CWA...AND IN COMBINATION WITH HIGHER LEVEL MOISTURE SLIDING OVER THE AREA...SHOULD PREVENT FORMATION OF ANY SIGNIFICANT FOG. THIN SLIVER OF CLEARING IN LOW LEVELS ACROSS WRN CWA EVIDENT ON SFC OBS...JUST AHEAD OF INVERTED TROF AXIS...BUT COVERED BY HIGHER CLOUDS PER SATELLITE IMAGERY. 00Z RUC HAS A GOOD HANDLE ON THIS CLEARING AREA ON 925MB RH INIT... AND FORECASTS RH TO GRADUALLY SPREAD BACK INTO THE AREA AS WEAK LOW LEVEL TROF WORKS EAST...SO CLOUDY FORECAST SHOULD HOLD UP WELL. GIVEN CLOUD COVER...FORECAST LOWS MAY BE ON THE LOW SIDE...BUT WILL NOT MAKE ANY CHANGES TO THE GOING FORECAST AT THIS TIME. .FSD...NONE HAMEN sd AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 1015 AM CST MON MAR 20 2000 UPDATED ZONES FOR WINDS...WITH SOME MINOR ADJUSTMENTS TO TEMPS AND POPS. 88D SHOWING A FEW AREAS OF -SN WESTERN 1/2 OF CWA...MOVING NE WITH MEAN UPPER FLOW. INVERTED SFC TROUGH ORIENTED N-S THROUGH CNTL SD. TEMPS GENERALLY ABOVE FREEZING...WITH 35-40 FAR W AND SW CWA...AND 30-35 N CNTL CWA. A FEW SMALL AREAS OF INCREASED INTENSITY SEEN ON 88D...BUT WITH MARGINAL TEMPS AND GENERALLY QUICK MOVT...NOT EXPECTING ANY ACCUMULATIONS. DECREASED WINDS FAR EAST AS SFC PRSR GRADIENT HAS DECREASED THERE. RUC INDICATES SIGNIFICANT DRYING IN THE FAR EAST...SO HAVE MENTIONED DECREASING CLOUDINESS BY LATE AFTERNOON...BUT MID AND HIGH CLOUDS WILL REMAIN. .ABR...NONE. LORENS sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EL PASO TX/SANTA TERESA NM 905 AM MST MON MAR 20 2000 DISCUSSION... WILL BE UPDATING PACKAGE MIDDAY TO EXTEND WIND ADVISORY INTO EVENING IF NOTHING ELSE. HOWEVER RUC-2 INDICATES 50KT WINDS AT 800 MB OVER SW NM SO AM DEBATING ABOUT WIND WARNING FOR A FEW HOURS LATE THIS AFTERNOON AND EVENING FOR SW NM. MUCH MAY DEPEND ON WHETHER ANY HIGH BASED CONVECTION DEVELOPS OVER SW TO ENHANCE SURFACE WIND - RIGHT NOW AM LEANING AGAINST THIS. OTHERWISE MORNING PACKAGE OK. .ELP...NONE 02 N tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 155 AM EST TUE MAR 21 2000 --CURRENTLY-- WATER VAPOR IMAGES SHOW DEEP UPPER LOW SAGGING S TOWARD NW MEXICO WHILE DOWNSTREAM UPPER RIDGING CONTINUES OVER THE MS VALLEY WITH ONLY A FEW HIGH CLOUDS SPILLING OVER INTO THE CWA. AT THE SURFACE ...A BROAD SURFACE RIDGE OF HIGH PRESSURE EXTENDS S THROUGH THE SE USA...RESULTING IN LIGHT WINDS OVER THE CWA. --FORECAST-- TODAY THROUGH WEDNESDAY - UPPER RIDGE TO CONTINUE AMPLIFYING OVER THE MS VALLEY...RESULTING IN DRY NW FLOW ALOFT OVER THE CWA. AT THE SURFACE... ANTICYCLOGENESIS OVER THE OH VALLEY WILL REINFORCE OFFSHORE FLOW OVER THE CWA. GUIDANCE TEMPERATURES SOMEWHAT ABOVE CLIMATOLOGY ARE ACCEPTED. MARINE - BUOYS AND C-MAN STATIONS CURRENTLY SHOW VERY LIGHT OFFSHORE FLOW. 05Z RUC PROGS FLOW TO VEER TO E AND STRENGTHEN TO 10-15 KNOTS BY 15Z. GENERALLY NE FLOW IN THE 10-15 KNOT RANGE PROGGED TO CONTINUE FOR REST OF PERIOD THANKS TO DEVELOPING SURFACE PRESSURE RIDGE OVER OH VALLEY. FIRE WEATHER - UNSEASONABLY WARM DAYTIME TEMPERATURES AND OFFSHORE FLOW OF DRY CONTINENTAL AIR WILL REQUIRE A RED FLAG WARNING THIS AFTERNOON AND A FIRE WEATHER WATCH WEDNESDAY AFTERNOON FOR LOW RELATIVE HUMIDITY DURATIONS FOR ALL FL ZONES EXCEPT THE IMMEDIATE COASTAL AREAS. EXTENDED (WEDNESDAY NIGHT THROUGH SATURDAY) - UPPER LOW OVER SW USA TO OPEN AND SHEAR NE WELL TO THE NW OF OUR CWA. UPPER RIDGE JUST W OF OUR CWA WILL CONSEQUENTLY TRANSLATE SLOWLY E AND THEN FLATTEN. ABOVE NORMAL HEIGHTS AND TEMPERATURES SHOULD PERSIST. IT APPEARS THAT MOIST RETURN OFF THE GULF WILL COMMENCE BY FRIDAY EVENING. AN APPROACHING COLD FRONT FROM THE N COULD BRING A SLIGHT CHANCE OF RAIN BY THE VERY END OF THIS PERIOD...BUT WITH LOW CONFIDENCE AND MANY INTERVENING FORECAST PACKAGES BETWEEN NOW AND THEN...WILL KEEP EXTENDED DRY FOR NOW. INPUT IS ALWAYS WELCOME. PRELIMINARY NUMBERS... TLH 080/048 078/048 0000 PFN 072/051 076/052 0000 DHN 076/050 079/050 0000 ABY 077/050 076/049 0000 VLD 079/050 079/048 0000 .TLH... AL...NONE. GA...NONE. FL...RED FLAG WARNING THIS AFTN AND FIRE WEATHER WATCH WED AFTN ALL ZONES EXCEPT FLZ012-014-015. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 420 AM EST TUE MAR 21 2000 MAIN FCST CONCERNS THIS PACKAGE INCLUDE LINGERING AREAS OF DENSE FOG ALONG WITH PRECIP POTENTIAL TONIGHT. WV IMAGERY SHOWED CONTINUED SPLIT FLOW PATTERN WITH STRONG CUTOFF LO OVER AZ AND ANOTHER OVER SW OH. JET PUSHING INTO WRN CANADA WL HELP REASSERT INFLUENCE OF NRN STREAM ON WEATHER OVER WRN GRT LAKES. KMQT/KGRB 88DS INDICATED -RA/-DZ FROM KEWEENAW SOUTH INTO PORTIONS OF NE WI. PCPN SUPPORTED BY MID LVL DEFORMATION AND ASSOCIATED 700-300 QVECTOR CONVERGENCE BTWN OH CUTOFF AND NRN STREAM FLOW FROM MN INTO ONTARIO. SFC ANALYSIS INDICATED A COL OVER OVER NW WI. LIGHT EAST OR SE FLOW UPSLOPE FLOW OF VERY MOIST AIR ACRS CNTRL UPR MI HELPING TO MAINTAIN DENSE FOG WITH VSBYS AOB 1/4SM FROM CMX TO SAW. -RA AT IMT HAS BROUGH TEMPORARY IMPROVEMENT WITH VSBY UP TO 2SM. TODAY...00Z ETA AND 06Z RUC SHOW DEFORMATION ZONE AND 700-300 QVECTOR CONVERGENCE PERSISTING OVER CNTRL UPR MI BUT WEAKENING TOWARD AFTERNOON. SO...WL KEEP MENTION OF MORNING SCT -RA/-DZ. AXIS OF WEAK SFC CONVERGENCE ALSO REMAINS OVER CNTRL UPR MI AS COL FCST TO SINK SLOWLY SE. THIS SHOULD HELP KEEP AREAS OF DENSE FOG GOING MUCH OF THE MORNING. HOWEVER...EXPECT IMPROVEMENT TOWARD AFTERNOON WITH SOME DIURNAL WARMING. TONIGHT...NRN STREAM SHRTWV WILL MOVE QUICKLY THROUGH SRN CANADA AND NRN PLAINS TOWARD UPR MI. ETA HAS BEEN MOST CONSISTENT WITH THIS FEATURE AND HAVE FOLLOWED FOR DETAILS. WHILE BEST 700-300 QVECTOR CONVERGENCE REMAINS A BIT TO THE NORTH...ENOUGH BRUSHES AREA ALONG WITH LLVL CONVERGENCE WITH SFC TROF TO ADD MENTION OF SCT LIGHT PCPN. EXPECT AMOUNTS OF ONLY TRACE TO A FEW HUNDREDTHS AT MOST. FCST SNDGS ALSO SHOW PERSISTENT 800-650 DRY LYR. WEDNESDAY...GOOD QVECTOR DIV IN WAKE OF SHRTWV ALONG WITH INCREASING DRY LLVL WRLY FLOW SHOULD BRING CLEARING AND SUNSHINE BY AFTERNOON FROM WEST TO EAST. FCST TEMP RANGE IN LOW 50S LOOKS ON TRACK WITH PLENTY OF AFTERNOON SUNSHINE ALLOWING FOR MIXING AOA H85 WHERE TEMPS CLIMB TO AROUND -1C. DOWNSLOPE FLOW SHOULD ALSO BRING ADDITIONAL WARMING TO CNTRL UPR MI. 950 WINDS TO AROUND 15 KNOTS SHOULD ALSO LIMIT LK BREEZE POTENTIAL VCTNY MQT-MUNISING TIL LATER IN THE AFTERNOON AFTER TEMPS REACH FCST MAX. .MQT...DENSE FOG ADVY THIS MORNING MIZ001-003>005-010>012. JLB mi 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 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 WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION. NATIONAL WEATHER SERVICE GRAND JUNCTION CO 300 AM MST TUE MAR 21 2000 SNOW EMPHASIS SHIFTS SOUTH AND EAST TODAY...WITH WARNINGS TO CONTINUE FOR SOUTHERN ZONES. 500-700MB LOW WOBBLING AND SLOWLY FILLING OVER AZ THIS MORNING WITH SFC LOW NEAR ABQ. AREAS OF SNOWFALL HAVE CONTINUED THIS EARLY MORNING IN WET DIVERGENT SE FLOW ALOFT OVER-RUNNING COLD NE SFC FLOW. GOOD INITIALIZATION IN THE 00Z MODELS. FOR TODAY...SYNOPTIC-SCALE FORCING SEEN IN THE Q/OMEGA FIELDS MAINLY SOUTH AND ALONG THE CONTINENTAL DIVIDE. FORECAST SOUNDINGS SHOW VERTICAL WIND PROFILES BACKING TO EAST FOR ALL WESTERN ZONES BUT VEERING E-S FOR SOUTHERN AND EASTERN ZONES...CONDUCIVE FOR MORE SNOWFALL. STEEP LAPSE RATES SOUTH LEAN TOWARDS AREAS OF HEAVY CONVECTIVE SHOWERS TODAY. WILL ALSO INCLUDE UTAH ZONE28 (MONTICELLO/LA SALS/ABAJOS) IN THE BLOWING SNOW ADVISORY. SNOW MODEL CONTINUES TO PRODUCE 2-6 INCHES OF OROGRAPHIC SNOW FOR THE SAN JUANS AND AREAS ALONG THE CONTINENTAL DIVIDE INTO THE CENTRAL MOUNTAINS (COZ10-12). PRECIP FOR THESE ZONES WILL BE MORE SCATTERED...BUT THINK MOST VALLEY LOCATIONS SUCH AS ASPEN AND CRESTED BUTTE WILL SEE LIGHTER ACCUMULATIONS. SO WILL LET WARNING EXPIRE THERE. GUSTY EAST WINDS WILL CONTINUE TO PLAGUE ALL PASSES ALONG THE CONTINENTAL DIVIDE...BUT HIGH WIND WARNING CRITERIA NOT EXPECTED TO BE MET AS SFC-700MB GRADIENT PROGGED TO SLACKEN THRU TODAY. TONIGHT...AS LOW CONTINUES TO FILL AND RETROGRADE...LESS FORCING EXPECTED FOR EVEN THE SOUTHERN ZONES. WITH RUC AND LAMP MESO POP GUIDANCE ALREADY CUTTING BACK FOR THIS AFTERNOON...WILL UNDERCUT GUIDANCE TONIGHT...ESPECIALLY WEST. STRONGEST WINDS SOUTH IN THE TIGHTEST GRADIENT. 300 JET STREAKS BECOMING MORE SYMMETRICAL ABOUT THE LOW...BUT TOO FAR EAST AND WEST FOR MUCH ASSISTANCE IN THIS CWFA. WEDNESDAY...THE LOW BEGINS TO KICK FURTHER SOUTH THAN PREVIOUS PROGGED...NOW ALONG THE MEXICAN BORDER. SO WILL LOWER POPS NORTH AND CENTRAL. EXTENDED: KICKER REMAINS PROGRESSIVE THURSDAY FOR A BRUSH OF NORTHERN POPS FRIDAY. BUT NEXT SYSTEM PROGGED TO CLOSE AGAIN OVER AZ BY SUNDAY. WILL LEAVE SATURDAY DRY FOR NOW. 99/RAMEY .GJT...WINTER STORM WARNING TODAY FOR CO ZONES 18/19/22/23. SNOW AND BLOWING SNOW ADVISORY TODAY FOR UT ZONE 22/28 AND CO ZONE 21. co 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 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 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