SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO 345 AM MST FRI MAR 31 2000 ...SNOWFALL AMOUNTS CHALLENGE OF THE DAY... ONE OF THOSE DAYS WHEN YOU CAN USE THE MODELS FOR GENERAL ORIENTATION BUT MUST RELY ON SHORT-TERM TRENDS FOR THE DETAILS. SO FAR...WARNINGS/ADVISORIES...APPEAR TO BE WORKING OUT NICELY. SEE PUEBLO LOCAL STORM REPORTS (DENLSRPUB) FOR DETAILS ON SNOWFALL ACCUMULATIONS SO FAR. MAIN ISSUE TO RESOLVE THIS MORNING...WHETHER OR NOT TO EXPAND/DISCONTINUE WARNINGS/ADVISORIES ANYWHERE. EARLY THIS MORNING...THE ONLY MODEL TO HAVE ANY KIND OF A HANDLE ON THE TRUE SURFACE WINDS ACROSS THE PLAINS IS THE RUC...INDICATING NORTHERLY SURFACE WINDS ALONG THE FRONT RANGE...IN THE COLD AIR DAMMING WEDGE...THAT SHOT SOUTH ALONG THE FRONT RANGE INTO PUEBLO COUNTY LATE THURSDAY AFTERNOON. THIS IS THE WEDGE OF COLDER/DRYER CP AIR THAT TURNED THE PRECIP INTO SNOW ALONG THE SOUTHERN COLORADO FRONT RANGE I-25 CORRIDOR LATE THURSDAY/THURSDAY EVENING. THE OTHER MODELS SAY THE SURFACE WINDS SHOULD BE OUT OF THE EAST TO NORTHEAST RIGHT NOW...AND THEY ARE INCORRECT. WILL TRY TO EXTRAPOLATE THE SHORT TERM FORECAST BASED ON CURRENT RUC/SATELLITE/RADAR TRENDS. APPEARS THAT UPPER LOW CENTER IS PRESENTLY SITUATED OVER NORTHWEST ARIZONA AND TRACKING SOUTH. UPPER LOW IS EJECTING POTENT...QUICK MOVING SHORTWAVES INTO SOUTH CENTRAL/SOUTHEAST COLORADO. AT THE PRESENT TIME...EACH LOBE THAT EJECTS NORTHEAST HAS SOME PRETTY GOOD LIFT ASSOICATED WITH IT...AND IS CONVECTIVE IN NATURE BASED ON SATELLITE/LIGHTNING DATA. BEING IN THE DIFFLUENT (AND APPARENTLY DIVERGENT) NORTHEAST QUADRANT OF THE LOW...EACH BAND OF CLOUDS/ PRECIPITATION THAT ROTATES OUR WAY BLOSSOMS NICELY...WITH NICE EXPANDING/COOLING OF CLOUD TOPS NOTED IN SATELLITE IMAGERY. RECENT SATELLITE PICTURES INDICATE MORE EXPANDING/COOLING TOPS DEVELOPING OVER CENTRAL NEW MEXICO...HEADED FOR SOUTHERN COLORADO. AS THE UPPER LOW DROPS SOUTH THROUGH WESTERN ARIZONA WITH TIME...NOT CERTAIN HOW LONG THE SHORTWAVES MOVING INTO SOUTHERN COLORADO WILL REMAIN POTENT...BUT FOR NOW WILL RIDE THE WAVE...AND PLAY CURRENT TRENDS. THIS MEANS THAT THE COMBINATION OF UPPER LEVEL LIFT (MAINLY WAA) ASSOCIATED WITH THE SHORTWAVES AND LOW/MID LEVEL UPSLOPE (CAA) ASSOCIATED WITH THE LOW/MID LEVEL FRONT WILL KEEP US WITH PERIODS OF SNOW (SOME RAIN OVER THE LOWEST REACHES OF THE LOWER ARKANSAS VALLEY) THROUGH TODAY. SEE NO REASON TO DISCONTINUE ANY OF THE PRESENT WARNINGS/ADVISORIES EXCEPT POSSIBLY FOR 58/59...AS HAVEN'T SEEN ANYTHING SIGNIFICANT AT LXV YET. WILL LEAVE IT ALONE THOUGH AS FAIRLY CERTAIN SOME OF THE EASTERN SLOPES OF THE SAWATCH RANGE MAY BE GETTING HIT AND WE JUST DON'T KNOW IT YET. ELSEWHERE...SALIDA DCP HAS INDICATED .30 INCHES OF LIQUID SINCE ABOUT 1Z SO LOOKS GOOD FOR 68/69. ALL OTHER AREAS...WE HAVE RECEIVED REPORTS OF AT LEAST A FEW INCHES OF SNOW BUT IN MOST CASES SEVERAL INCHES. WILL EXPAND WINTER STORM WARNING TO COVER THE SAN LUIS VALLEY FOR TODAY...AS WE HAVE ALREADY HAD REPORTS OF 4 TO 6 INCHES REPORTED FROM ALS AND CENTER, RESPECTIVELY. STILL SNOWING THERE ACCORDING TO ALS ASOS. NOT SURE IF BRUNT HAS ALREADY PASSED OR NOT. BUT BASED ON SATELLITE SHOULD BE SOME ADDITIONAL ACTIVITY SPREADING INTO THE VALLEY YET THIS MORNING. WILL ALSO UPGRADE ADVISORY FOR 60/61 TO A WARNING BASED ON SATELLITE AND FOR CONSISTENCY. ACROSS THE PLAINS...MAIN CHANGE FROM PREVIOUS FORECAST WILL BE TO CHANGE PRECIPITATION TO MOSTLY SNOW...EXCEPT FOR SOME OF THE LOWER REACHES OF THE ARKANSAS VALLEY...WHERE ELEVATION/HIGHER DEWPOINTS MAY KEEP SOME RAIN AROUND. WILL ALSO ADD SOME LIGHT ACCUMULATIONS TO MOST PLAINS LOCATIONS BUT NOT GO HOG WILD AS SNOW SHOULD STAY PRETTY WET AND HAVE TROUBLE ACCUMULATING. STILL...AN INCH OR TWO (MAINLY ON GRASSY AREAS AND GENERALLY NOT ON ROADS) CERTAINLY WITHIN REASON. TONIGHT...LOOKS LIKE WE COULD STILL BE SEEING SOME WIDESPREAD SNOW AROUND THE REGION...ALTHOUGH SHOULD BE OF THE LIGHTER TYPE...AS H7 TEMPS COOL AND ABSOLUTE HUMIDITIES DECREASE. AT THE SAME TIMEE...SNOWFALL WILL LIKELY BECOME OF THE LIGHTER/FLUFFIER NATURE AND MAY ACCUMULATE BETTER WITH THE COOLER TEMPERATURES. WILL KEEP HIGH POPS IN THE FORECAST FOR TONIGHT MOST AREAS. WILL BEGIN TO DECREASE ACTIVITY ALL AREAS LATE TONIGHT/SATURDAY AS EVERYTHING BEGINS TO PULL SOUTH AND DRYER AIR ENCROACHES FROM THE NORTH. NO TIME FOR EXTENDED REVIEW THIS MORNING. WILL LEAVE AS IS. .PUB...WINTER STORM WARNING 60/61/62/63/64/65/66/67/70/74/75 TODAY SNOW ADVISORY 58/59/68/69/72 TODAY co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 915 PM EST FRI MAR 31 2000 ZONES: FCST LOOKS WELL ON TRACK AS MAIN CHALLENGE OVERNIGHT WILL BE COVERAGE AND DENSITY OF FOG. RIGHT NOW...SEE LITTLE REASON TO UPDATE CURRENT WORDING...BUT MID SHIFT WILL NEED TO KEEP A CLOSE WATCH WITH LIGHT WINDS...AMPLE LOW LEVEL MOISTURE...AND TLH 00 UTC SOUNDING ALREADY SHOWING AN INVERSION AT 900 FT. MARINE: WILL HAVE TO ADJUST WINDS AND SEAS DOWN WITH THE SFC HIGH SITTING IN PLACE OVER THE NORTHERN GULF. THE 12 UTC MODELS MAY HAVE BEEN A BIT AGGRESSIVE IN TIGHTENING THE PRESSURE GRADIENT TOWARDS SATURDAY MORNING...BUT WILL LEAVE THE 2ND PERIOD ALONE AS 00 UTC RUC STILL SHOWS THIS TIGHTENING MATERIALIZING. .TLH... AL...NONE GA...NONE. FL...NONE. GOULD fl EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 930 AM EST FRI MAR 31 2000 CURRENTLY...ERSTWHILE Q-STATIONARY BOUNDARY NOW STARTING TO MAKE STEADY SOUTHWARD PROGRESS. AS OF 14Z IT WAS ALONG A TTS-KSM-TPA LINE. DEW POINTS L70S SOUTH OF THE BOUNDARY...AND EARLY VISIBLE SATELLITE PICS SHOW ENOUGH BREAKS IN THE CLOUDS TO ALLOW FOR DECENT HEATING. 12Z RAOBS SHOW MOISTURE POOLED INVOF THE BOUNDARY TO THE TUNE OF ABOUT 1.4" TO 1.5" OF PWAT. HENCE...THE AIR MASS OVER THE SOUTHERN COUNTIES SHOULD GET SUFFICIENTLY UNSTABLE TO ALLOW SOME CONVECTION TO REFIRE ALONG/SOUTH OF BOUNDARY. WHATEVER UPPER SUPPORT THERE WAS OVERNIGHT NOW APPEARS TO BE MOVING OFFSHORE PER THE LATEST RUC SHOWING A WEAK MID LEVEL RIPPLE NOW EAST OF THE STATE...AND WEAK TO NIL TO H25 JET DYNAMICS. NEVERTHELESS... BOUNDARY IS STILL MAINTAINING ITSELF...LIKELY A FUNCTION OF SURFACE CONVERGENCE...SO WILL NEED TO ADJUST POPS UPWARD OVER THE SOUTHERN COUNTIES. NORTH OF THE BOUNDARY...CLOUDS AND ADVECTION OF DRIER AIR SOUTHWARD FROM NORTH FLORIDA WILL INHIBIT RAIN CHANCES...AND WILL LOWER THERE. WILL ALSO LOWER TEMPS AS AFOREMENTIONED CLOUDS SHOULD BE TOUGH TO DISLODGE...WITH LOW LEVEL FLOW VEERING TO N-NE OFF THE ATLC. MARINE...WIND SHIFT NOW APPEARS TO BE ALMOST ALL THE WAY THROUGH THE FLG-COF LEG AND WILL CONTINUE ADVANCING SLOWLY SOUTHWARD. WILL LIKELY NEED TO SLACKEN THE WIND SPEEDS IN THE COF-JUP LEG WITH THE BOUNDARY SITTING OVER THAT AREA MOST OF THE DAY. .MLB...NONE. AVIATION/FIRE WX...CRISTALDI PUBLIC/MARINE...WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 930 AM EST FRI MAR 31 2000 NO SIGNIFICANT CHANGES PLANNED IN UPDATES. VISIBLE SATELLITE AND METARS SHOW LOW CLOUDS AND FOG GRADUALLY DISSIPATING OVER THE CWA. WILL REMOVE MENTION OF THESE FEATURES IN ZONE UPDATES. 12Z SOUNDINGS SUGGEST THAT FORECAST HIGHS ARE REASONABLE. WILL TWEAK WIND DIRECTIONS AND SPEED IN COASTAL WATERS FORECAST BASED ON BUOY DATA AND 13Z RUC OUTPUT...WHICH SHOWS FLOW OVER THE WATER RAPIDLY VEERING TO THE E BY LATE THIS AFTERNOON. ADEQUATE SURFACE MOISTURE THIS AFTERNOON SHOULD PRECLUDE FIRE WEATHER THREAT AND SHOULD RESULT IN SCATTERED AFTERNOON CONVECTIVE CLOUDS...IN AGREEMENT WITH TAFS. INPUT IS ALWAYS WELCOME. .TLH... AL...NONE GA...NONE. FL...NONE. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 840 PM EST FRI MAR 31 2000 SYNOPSIS: LOW PRESSURE WHICH HAS RESULTED IN UNSETTLED CONDITIONS THE PAST FEW DAYS WILL MOVE EAST OF THE REGION OVERNIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA ON SATURDAY...THEN LOOK FOR A DISTURBANCE TO APPROACH THE REGION FROM THE WEST LATE SATURDAY NIGHT AND SUNDAY. TECHNICAL DISCUSSION: ENHANCED IR SAT LOOP FROM LATE THIS AFTERNOON INDICATED WEAK UPPER CIRCULATION ACROSS NORTHERN MAINE WHICH HAS MOVED EAST INTO NEW BRUNSWICK EARLY THIS EVENING. AFTERNOON RUC MODEL WAS THE ONLY ONE TO CATCH ONTO THIS. WITH FEATURE MOVING EAST LAST OF THE WEAK ECHOES ACROSS NORTHEAST MAINE HAVE DRIED UP. SURFACE FLOW BECOMING NORTHWEST WHICH IS ALLOWING CLOUDS TO BREAK UP ACROSS CENTRAL AREAS AND HAVE ALREADY RESULTED IN CLEAR TO PC CONDITIONS DOWNEAST. BASED ON SAT TREND EXPECT PLENTY OF CLOUDS TO REMAIN ACROSS THE NORTH WITH SOME BREAKS DEVELOPING WHILE MOSTLY CLR TO PC CONDS CONTINUE FOR CENTRAL AND DOWNEAST AREAS. MIN TEMP FCST LOOKS REASONABLE SO NOT ANTICIPATING MUCH CHANGE. OTHER THAN A COUPLE MINOR ADJUSTMENTS TO FIRST PERIOD...AFTERNOON PACKAGE LOOKS GOOD. LATEST INFORMATION FROM THE FORT FAIRFIELD PD INDICATES THE AROOSTOOK RIVER LEVEL REMAINS AT 12.5 FEET. THEY HAVE INDICATED PART OF THE ICE JAM HAS MOVED TOWARD TINKER. ALONG THE ST. JOHN RIVER...STATE POLICE REPORT THE RIVER LEVEL HAS DROPPED IN THE VAN BUREN AREA. AN FFS WILL BE ISSUED SHORTLY PERTAINING TO THESE TWO RIVERS. COASTAL WATERS: WIND EXPECTED TO REMAIN BELOW SCA CRITERIA THROUGH THE WEEKEND. .CAR...FLOOD WATCH FOR ZONE 2 OVERNIGHT THROUGH SATURDAY. FITZSIMMONS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 905 PM EST FRI MAR 31 2000 HIGH CLOUDINESS ACROSS THE AREA EARLIER IN THE EVENING HAS CLEARED OUT. 01Z SURFACE ANALYSIS SHOWING HIGH PRESSURE CENTERED OVER OHIO AND WV... AND 18Z ETA AND 21Z RUC PROG THAT HIGH TO MOVE OVER WESTERN HALF OF CWA BY 12Z. SOME COOLER DEW POINTS MOVING IN AS HIGH BUILDS OVERHEAD... WITH CURRENT READINGS IN THE MID AND UPPER 20S FOR THE NWRN SECTIONS OF THE CWA. LOWS WERE IN THE MID AND UPPER 20S OVER MUCH OF THE WESTERN HALF OF CWA LAST NIGHT.. AND WOULDN'T BE SURPRISED TO SEE SOME LOWER 20S TONIGHT IN SOME OF THE COLDER VALLEYS. FROST AND FREEZE WARNINGS IN EFFECT TONIGHT LOOK GOOD. MADE A COUPLE OF CHANGES TO LOWS OVERNIGHT BASED ON CURRENT DEW POINTS... BUT OVERALL FORECAST LOOKS GREAT. .LWX...FREEZE WARNING TNGT FOR MDZ002>004-VA021-025>031-042- WVZ048>055- FROST WARNING TNGT FOR MDZ005-006-009-010-VAZ036>041- 050>053-055-056- MARGRAF! md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 940 PM EST FRI MAR 31 2000 ANY CHANGES TO THE ERN UPR/NRN LWR MI ZONE FORECASTS WILL BE MAINLY THE COSMETIC VARIETY -- I.E. REMOVING EVENING REFERENCE. AT THIS POINT...ONGOING FCST APPEARS ON TARGET. CURRENTLY...WEAK SFC FRONT EXTENDS ACROSS ERN WI. LONGWAVE IR IMAGES SHOW AREA OF ENHANCED/ HIGHER CLOUD TOPS ALONG AND AHEAD OF THE FRONT EXTENDING FROM NRN WI THROUGH ERN LAKE SUPERIOR. HOWEVER SFC OBS OVER THESE AREAS SHOW BASES GENERALLY AT OR ABOVE 8000 FEET. ROAB AT GREEN BAY IN FACT SHOWS LIMITED MOISTURE BELOW 600 MB OR 14000 FEET. FARTHER TO THE WEST (BEHIND AREA OF MID/HIGH CLOUDS)...REGION OF COLD ADVECTION/ WRAP-AROUND STRATOCUMULUS ARE NOTED ACROSS THE NRN 2/3 OF MN. 00Z ETA/00Z RUC SIMILAR WITH 12Z RUNS IN TERMS OF DEGREE OF Q-G FORCING (OR LACK THERE OF) ACROSS THE REGION TONIGHT. CURRENTLY... MAIN UPPER CIRCULATION IS LOCATED N OF MN AS PER LATEST WV IMAGERY... WITH A SHORTWAVE TROUGH/VORT LOBE EXTENDING SOUTH INTO CENTRAL MN. THIS TROUGH WILL DE-AMPLIFY AS IT APPROACHES THE REGION AND ENCOUNTERS THE UPPER RIDGE. AS A RESULT...850-500 MB Q-VECTOR CONVERGENCE REMAINS WEAK TONIGHT. IF ANYTHING...Q-G CHARTS HINT AT WEAK UPPER CONVERGENCE/DOWNWARD FORCING ACROSS ERN UPR/NRN LWR MI UNDER THE RIGHT EXIT REGION OF A JET STREAK. THE SFC FRONT IS THUS EXPECTED TO CONTINUE TO FIZZLE AS IT PROGRESSES THROUGH THE REGION...WHILE HIGHEST (>70 PCT) 1000-500 MB LAYER AVERAGE MOISTURE REMAINS NE/SW OF THE REGION WHERE MORE FAVORABLE LEFT EXIT REGION/RIGHT ENTRANCE REGION FORCING IS RESPECTIVELY. SO...WITH DYNAMICS/DEEP MOISTURE SERIOUSLY LACKING...WILL CONTINUE TO LEAVE MENTION OF PRECIP OUT OF THE ZONES TONIGHT. GIVEN THE LACK OF MOISTURE IN FACT BELOW 600 MB AS PER LATEST (00Z) MODEL SOUNDINGS...EXPECT IT WILL BE TOUGH TO GENERATE EVEN A FEW SPRINKLES. ONLY MINOR MODIFICATIONS...IF ANY...ARE EXPECTED WITH THE OVERNIGHT LOW TEMP FCST. UPDATED ZONES TO ROLL AROUND 10 PM. .APX...NONE. HURLEY mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 820 PM CST FRI MAR 31 2000 COLD AIR SC OVER N MN SLIDING SLOWLY EAST BUT NOT MUCH SOUTHWARD MOVEMENT. 1000-850 MB RH FORECAST OF 00Z RUC DOES KEEP MOISTURE MAINLY NORTH OF CWA BUT BRUSHING PART OF AREA AS CURRENT SATELLITE TRENDS SHOW. FARTHER SOUTH..00Z RAOB FROM KOAX QUITE MOIST AND HIGH CLOUDINESS PUSHING NW AT THIS TIME. 00Z RUC CARRIES THIS MOISTURE NE OVERNIGHT. CURRENT FORECAST FRO PARTLY CLOUDY LOOKS OK MOST AREAS BUT WILL BEEF UP CLOUDS IN SOUTH CENTRAL. MAY NEED TO RAISE TEMPS A BIT TOO. .MSP...NONE. RICHARDSON mn AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 840 PM CST FRI MAR 31 2000 SATELLITE...SFC OBS AND RADAR MOSAIC SHOW THAT MUCH OF THE CLOUDS AND ECHOES ACROSS THE REGION WERE ON THE DECREASE AS SFC HEATING HAS DISAPPEARED. ALTHOUGH SOME MID LEVEL CLOUDS AND WDLY SCT -SHRAS REMAIN WITH THE COLD POOL OF AIR (S/W) MOVING SE OVER THE WESTERN PART OF THE REGION THIS EVENING. BELIEVE THE -SHRAS WILL DISSIPATE YET THIS EVENING AS THE S/W MOVES SE WITH MUCH OF THE MID LEVEL CLOUDS REMAINING. THE RUC AND ETA MDLS SHOW THIS S/W MOVING SE TONIGHT WITH THE MEAN RH IN THE 50-70% RANGE. THIS SHOULD CONTINUE TO ALLOW FOR SCT TO SOME BKN AREAS OF MID LEVEL CLOUDS MOVING ACROSS THE CWA TONIGHT. LIGHT NW WINDS IN ADVANCE OF WK SFC TROUGH WILL GO TO THE SW ACROSS MUCH OF THE CWA. DESPITE LOW DWPTS AND LIGHT WINDS...MID CLOUDS SHOULD KEEP TEMPS FROM FALLING OFF TOO FAR. UPDATED FORECAST TO MAKE SEVERAL CHANGES. .ABR...NONE MOHR sd AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1015 AM CST FRI MAR 31 2000 APPEARS ANOTHER WELL MIXED DAY IN STORE FOR CWA IN MIDST OF LOW LVL CAA AND WLY COMPONENT TO FLOW. SECONDARY CDFNT THRU NWRN 3RD OF SD. FOR NOW...MID/HI CLDS OVR SERN HALF OF CWA ARE CONTINUING TO PULL AWAY...BUT WL SEE CI CLAIMING GROUND ACRS SRN HALF OF REGION THRU AFTN. ALSO...RAOBS AND FCST RUC SOUNDING INDICATE SOME POTENTIAL FOR SC FORMATION THRU AFTN...ESPLY N WHERE FLOW IS MOST CYCLONIC... AND COLDEST ALFT. EVEN WITH INCREASED SUNSHINE N...RAOBS SUGGEST THAT TEMPERATURE POTENTIAL BY MIXING SHOULD ONLY REACH MID TO UPPER 50S MOST AREAS...MAYBE LWR 60S FAR S. WNDS MAY BE A TAD ON THE LOW SIDE ACRS N AS WELL. WL MAINLY CLEAN UP TO TAKE OUT MENTION OF SPRINKLES OR LIGHT SHOWERS IN SERN PTN OF CWA...AND BE MORE OPTIMISTIC ON SUNSHINE MOST AREAS. .FSD...NONE CHAPMAN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 250 PM CST FRI MAR 31 2000 FORECAST QUANDARIES...PCPN AMOUNTS AFTER 06Z SUN...TEMPERATURES. CURRENT ASOS/AWOS OBSERVATIONS...SATELLITE IMAGERY...AND LAPS/SURFACE ANALYSES SHOWING SURFACE RIDGING INFLUENCES CENTERED ACROSS S IL...RESULTING IN MOSTLY SUNNY SKIES...NORTHERNLY SURFACE WINDS...AND DEWPOINTS RANGING MID 30S TO MID 40S. UPPER AIR RUC/CHART ANALYSES ILLUSTRATING RIDGING INFLUENCES ALSO ALOFT. 18Z RUC INITIALIZING A 100KT+ JET OVER CENTRAL AL AND MS. 12Z FRI REGIONAL MODEL INITIALIZATIONS AND PROGGED EVOLUTION THROUGH 00Z MON SIMILAR. MODELS MOVING CURRENT HIGH PRESSURE SYSTEM EAST AND EXPECT IT TO APPROACH THE MID ATLANTIC COAST BY 18Z SAT. THIS WILL RESULT IN INCREASED CLOUDINESS DURING THE DAY ON SAT AS SOUTHERLY SURFACE FLOW ADVECTS MOISTURE INTO REGION. UPPER LEVEL FLOW WILL BRING IN ADDITIONAL MID AND UPPER LEVEL MOISTURE ACROSS REGION AS FLOW DEVELOPS A MORE SW FETCH ASSOCIATED WITH DEEPENING UPPER LEVEL LOW/TROUGH ACROSS THE W U.S. IN AGREEMENT WITH LATEST MODEL DIAGNOSTIC DISCUSSION THAT ETA/AVN SOLUTIONS HAVE A BETTER HANDLE ON LOW PRESSURE SYSTEM DEVELOPMENT ACROSS LOWER MS VALLEY REGION BY 06Z SUN. THESE TWO MODELS BRING FRONTAL SYSTEM ACROSS AREA BY 12Z SUN AND DEVELOP A STRONG LOW PRESSURE SYSTEM ACROSS THE UPPER MS VALLEY BY 00Z MON. PCPN POPS EXPECTED "TO REACH" CATEGORICAL STATUS DURING THE DAY ON SUNDAY AS BEST ATMOSPHERIC DYNAMICS WILL BE IN PLACE. RAINFALL COULD POSSIBLY BE HEAVY AT TIMES. THERE IS SOME DISAGREEMENT WITH BOTH THE ETA/AVN PROGGING IN EXCESS OF ONE INCH BETWEEN 06Z AND 12Z SUN ACROSS REGION WITH 6 ORLY ONE INCH PRECIPITATION AMOUNTS OVER SOUTHERN CWA AT 18Z SUN AND 00Z MON. HOWEVER...DAY TWO QPF VALUES SHOWING MORE IN LINE WITH THE NGM SOLUTION. EVENTHOUGH THIS IS AN OVER-RUNNING RAINFALL EVENT...ATMOSPHERIC INSTABILITY MAY BE ENOUGH TO SUPPORT SOME ITS DEVELOPMENT DUE TO PRONOUNCED INSTABILITY ADVECTION AND 850MB PROGRESSIVE JET DYNAMICS. TEMPERATURES...WILL COMPROMISE BETWEEN AVN FAN/NGM MOS VALUES TONIGHT FOR LOWS. DESPITE SOUTHERLY WIND FLOW DEVELOPMENT ON SAT...BELIEVE INCREASED CLOUDINESS WILL INHIBIT TEMPERATURES FROM REACHING AVN FAN HIGHS. WILL TREND TOWARD NGM MOS/ETA IN HOUSE BOUNDARY TEMPERATURE SCHEME VALUES FOR SAT HIGHS. WILL GO WITH AVN FAN/NGM MOS LOW VALUES FOR SAT NIGHT. AGAIN QUESTION AVN FAN HIGHS ON SUNDAY. WILL TREND TOWARD THE MORE CONSERVATIVE NGM MOS VALUES HERE. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 045/071/056/068 0188 CSV 040/068/052/063 0078 .BNA...NONE. 14 JBW tn TEXAS/OKLAHOMA PANHANDLES FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 600 AM CST FRI MAR 31 2000 RAPID SHRA/TSRA DEVELOPMENT ACROSS S PLAINS INTO ERN TX PNHDL ATTM. UPDATED ZNS TO TAKE MENTION OF AFTN OUT OF NE ZN GROUPING. ALSO...TEMP AT KCAO DROPPED ANOTHER COUPLE DEGREES WITH ASOS NOW REPORTING SN. MESONET DATA STILL SHOWING E WINDS AT BOISE CITY HOWEVER KENTON HAS BACKED TO NE. LATEST WINTER COMPOSITE FM 09Z RUC INDICATES SNOW CHCS INCREASING THROUGH 18Z ACROSS CIMARRON/DALLAM COUNTIES. WILL CONTINUE TO MONITOR THAT AREA CLOSELY FOR CHANGE TO SNOW AND POSSIBLE ADVISORY. .AMA... TX...NONE. OK...NONE. COBB tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 910 PM EST FRI MAR 31 2000 AWIPS IR SATELLITE LOOP INDICATED A FEW HIGH CLOUDS COASTING EAST ACROSS RNK FA. MOISTURE CHANNEL IMAGES SHOWED A SHORTWAVE DROPPING SOUTHEAST THIS EVENING. 00Z RNK SOUNDING WAS REALLY DRY WITH A LIGHT NW FLOW AND PWAT AT 0.14 INCHES. A THIN LAYER OF MOISTURE NOTED FROM 480 TO 420 MB. 00Z SFC CHART REPORTED TEMPERATURES FROM AROUND 45 IN ALLEGHANY HIGHLANDS TO AROUND 60 IN NORTHERN NC. MODELS YIELDED FAIRLY SIMILAR SOLUTIONS DURING THE PERIOD. 18Z MESO-ETA AND 23Z RUC SUPPORTED CURRENT PACKAGE. AT 5H...VORT MAX PIVOTS SOUTHEAST AROUND THE RIDGE. SFC HIGH BUILDS OVERHEAD BY 12Z ON THE 1ST THEN MOVES OFF THE EAST COAST BY 12Z SUNDAY. COLD FRONT LOCATED FROM WI TO TX THIS EVENING WILL MARCH EAST AND CROSS OUR AREA LATE SAT NIGHT INTO SUNDAY. DEEPEST AND RICHEST MOISTURE WILL ARRIVE LATE SAT NIGHT /EARLY SUNDAY IN CWA. AVN AND ETA QPF PRINTED OUT OVER AN INCH ACROSS TN AT 48 HOURS. TONIGHTS FORECAST IS ON TRACK WITH A MOSTLY CLEAR SKY AND AREAS OF FROST. MAY TWEAK TEMPS DOWN IN A FEW SPOTS AFTER CHECKING LATEST OBS. SATURDAY WILL HAVE INCREASING CLOUDS. ZONES WILL ARRIVE AROUND 930 PM. HAVE A GOOD NIGHT. .RNK VA...NONE. WV...NONE. NC...NONE. KK va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 240 AM CST SAT APR 1 2000 FORECAST CHALLENGES -- LONGEVITY OF PRECIPITATION THIS MORNING AND ADDITIONAL CHANCES SUNDAY AFTERNOON. SYNOPSIS -- EARLY MORNING REGIONAL 88D REFLECTIVITY MOSAIC CONTINUES TO SHOW AN AREA OF LIGHT RAIN FROM S CNTRL NEB NEWD THRU THE OMA METRO INTO CNTRL IA. THIS AREA OF PRECIPITATION WAS OCCURRING IN A ZONE OF ENHANCED UPWARD VERTICAL ASCENT IN THE RIGHT REAR QUADRANT OF A JET STREAK THAT EXTENDED FROM NRN WI TO ERN SD PER LATEST 06Z/01 RUC 250MB ISOTACH AND DIVERGENCE 0-HR FORECAST. THE RUC INDICATES A WEAKENING DIVERGENT PATTERN THRU THE REMAINDER OF THE MORNING...WHICH IS SUPPORTED BY RECENT TRENDS IN THE IR IMAGERY WITH WARMING CLOUD TOPS OVER ERN NEB AND IA. FORECAST -- DPROG/DT 500MB HEIGHT AND VORTICITY FIELDS FROM THE ETA AND AVN INDICATE A SLIGHTLY SLOWER AND NOTICEABLY DEEPER SHORTWAVE DIVING INTO THE NRN PLAINS ON SUNDAY. THIS SUPPORTS A SLIGHTLY SLOWER BUT MORE BAROCLINIC SURFACE FRONT WITH THIS SYSTEM...MORE IN LINE WITH THE ETA AND AVN HANDLING. IN THE SHORT TERM...THE ENDING OF LIGHT RAIN IS THE MAIN CONCERN. AS MENTIONED ABOVE...THE UPPER LEVEL JET STREAK CONTINUES TO TRANSLATE AWAY FROM THE AREA THIS MORNING WITH A CONTINUED WEAKENING TREND TO THE PRECIPITATION SHIELD. WE WILL MONITOR RADAR AND SURFACE OBSERVATION DATA UP TO ZONE ISSUANCE AND WORD THE PRECIPITATION FORECAST ACCORDINGLY. OTHERWISE...CLOUDS SHOULD ERODE FROM NW TO SE TODAY WITH HIGH TEMPERATURES SLIGHTLY BELOW GUIDANCE. TONIGHT...SKIES SHOULD CLEAR BUT AN INCREASING SURFACE GRADIENT AFTER MIDNIGHT SHOULD KEEP TEMPERATURES FROM BOTTOMING OUT AND CLOSE TO GUIDANCE VALUES. SUNDAY...A STRONG SHORTWAVE DIVES INTO THE NRN PLAINS WITH A CONCOMITANT SURFACE FRONT PUSHING S THROUGH THE AREA. LOW LEVEL MOISTURE WILL REMAIN SCARCE AND LIKELY LIMITED TO WHAT CAN BE EVAPORATED FROM THIS MORNING'S RAIN. MID-LEVEL LAPSE RATES ARE FORECAST TO STEEPEN TO 6-7 DEG C/KM BY AFTERNOON AND THE COMBINATION OF LARGE SCALE LIFT ACROSS THE NRN ZONES AND MESOSCALE...FRONTAL LIFT IN THE S WARRANT CHANCE POPS FOR POTENTIAL SHOWER ACTIVITY. THESE STEEP LAPSE RATES SHOULD ALSO HASTEN POST-FRONTAL DOWNWARD MOMENTUM TRANSFER WITH WINDY CONDITIONS EXPECTED BY AFTERNOON. HIGH TEMPERATURES WILL LIKELY BE REACHED BY EARLY AFTERNOON IN THE N...WITH A FALLING TREND THEREAFTER. FARTHER S...THE AMOUNT OF MIXING AND COMPRESSIONAL PRE-FRONTAL WARMING WILL DICTATE HIGH TEMPERATURES. WE WILL GO CLOSE TO GUIDANCE ACROSS THE N...BUT SLIGHTLY ABOVE IN THE S. IN THE EXTENDED...WE WILL MAKE SOME SLIGHT ADJUSTMENTS TO THE CURRENT TEMPERATURE AND PRECIPITATION WORDING WITH NO OTHER CHANGES PLANNED. .OMA...NONE. MEAD ne NORTHERN ARIZONA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 900 AM SAT APR 1 2000 SYNOPSIS...A STORM SYSTEM CENTERED OVER SOUTHERN ARIZONA WILL CONTINUE TO SPREAD RAIN AND HIGHER ELEVATION SNOW SHOWERS ACROSS MUCH OF NORTHERN ARIZONA TODAY AND TONIGHT. SOME CLEARING WILL TAKE PLACE ACROSS NORTHWEST ARIZONA AS HIGH PRESSURE BEGINS TO BUILD INTO THE STATE. THIS HIGH PRESSURE SYSTEM WILL BUILD OVER ALL OF ARIZONA ON SUNDAY BRINGING MOSTLY CLEAR SKIES AND WARMING TEMPERATURES WHICH WILL LAST INTO MIDWEEK. DISCUSSION...SATELLITE SHOWS UPPER LOW LOCATED NEAR KTUS WITH SOME SOUTHWARD MOVEMENT. DEFORMATION ZONE TO NORTH CONTINUES TO SLOWLY SAG SOUTHWARD WITH A CURRENT POSITION FROM KBLH TO KPGA SOUTHWARD. TO THE NORTH OF THIS DEFORMATION ZONE...SKIES HAVE CLEARED AS THE AIRMASS STABALIZES. MODELS SUGGEST THAT THE UPPER LOW WILL CONTINUE SLOW SOUTHWARD MOVEMENT. THEY ALSO SUGGEST THAT THE DEFORMATION ZONE WILL SAG JUST A LITTLE MORE TO THE SOUTH BEFORE SLOWING DOWN. RUC 700-500MB CONDENSATION PRESSURE DEFICIT FIELD SHOWS THIS PERFECTLY WITH THE 100 MB LINE TRACING THE BACK EDGE TO THE DEFORMATION ZONE PERFECTLY. THUS...TO THE NORTH OF THIS LINE...WILL REMOVE MENTION OF SHOWERS AND MOSTLY CLOUDY SKIES. TO THE SOUTH OF THIS LINE WILL CONTINUE THREAT OF SHOWERS...DUE TO INSTABILITY PRESENT...BANDS OF LOCAL CONVERGENCE ROTATING AROUND THE UPPER LOW AND HIGHER PWAT VALUES. MODELS THEN TAKE CURRENT LOW SOUTHEASTWARD INTO NM BY SUNDAY AS THE RIDGE BEGINS TO MOVE INTO THE STATE FROM THE WEST. THIS WILL CONTINUE THE CURRENT WARMING TREND UNDERWAY INTO MIDWEEK. STAUDENMAIER .FGZ...NONE. az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KEY WEST FL 940 AM EST SAT APR 1 2000 CURRENTLY... VISIBLE SATELLITE LOOP SHOWS A LONG CUMULUS LINE ORIENTED NW-SE MOVING SW OVER MARQUESAS KEYS...FLORIDA STRAITS...SE GULF OF MEXICO. THIS FEATURE MARKS AN ONSET OF ENE WINDS 10-15 KTS AS IT MOVES THROUGH...AND PRODUCED A COUPLE OF VERY SHORT-LIVED FUNNEL CLOUDS WITHIN SIGHT OF KEY WEST AROUND 730-800 AM. ANOTHER SIMILAR LINE IS SEEN MOVING SW AS IT ENTERS THE MIDDLE KEYS AND ADJACENT STRAITS OVER TO ANDROS ISLAND. WINDS WITH THIS SECOND CU LINE ARE NE NEAR 15 KNOTS. MOLASSES REEF IS NE 15 KT PEAK GUST 17 KT AT 9 AM. LOW STRATUS MOVING W OFF THE MAINLAND SEEMS TO BE PASSING INTO GULF WATERS UPCOAST FROM CAPE SABLE. DEWPOINTS REMAIN HIGH OVER THE KEYS ...73-74F. FIRST PERIOD FORECASTS... AS HIGH PRESSURE BUILDS SOUTHWARD...WINDS HAVE BECOME NE AND ARE PICKING UP TO 15 KT AS INDICATED IN PREVIOUS FORECAST. LATEST RUC INDICATES 15-20 KT WINDS OVER UPPER KEYS BY 00Z THIS EVENING...BUT CURRENT FORECAST ALREADY IS STATING 15-20 KT FOR TONIGHT. THUS... 1030 AM COASTAL MARINE FORECAST WILL INDICATE THAT THE TRANSITION TO NE 15 KT HAS ALREADY OCCURRED AS EXPECTED...WITH FURTHER INCREASE STILL IN STORE FOR TONIGHT. PUBLIC ZONES WILL BE UPDATED SIMPLY TO REMOVE MORNING TIME REFERENCES FOR CLOUD COVER. THERE MAY BE SMALL SHOWERS OVER THE STRAITS...BUT THREAT OVER LAND SEEMS TOO SMALL TO ADD TO ZONES. .EYW...NONE. CLB fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CHARLESTON SC 1007 AM EST SAT APR 1 2000 RUC 1000-850 THICKNESS VALUES SUPPORT MAX TEMPS BTWN THE FAN/FWC GUIDANCE THIS AFTN...SLIGHTLY CLOSER TO THE NGM NUMBERS. 850 MB HIGH ATOP S CAROLINA THIS MORNING AND RETURN MOIST FLOW IS MAINLY S OF THE ALTAMAHA RVR WHERE THE BEST CHC OF ATLC STRATOCU WILL BE TDA. WILL CONTINUE WITH MOSTLY SUNNY FCST WITH ONLY A FEW MINOR CHANGES TO TEMPS AND WINDS EXPECTED. CWF...WK TROF JUST OFF THE COAST IS KEEPING PG PINCHED SLIGHTLY. WILL ADJUST WIND SPEEDS UP A LTL FOR INIT CONDS AND KEEP THE SCA FOR THE GA OFFSHORE WATERS. UPDATED TO HOIST SCA FOR S CAROLINA WATERS AND CHS HARBOR. .CHS... .SC...SMALL CRAFT ADVISORY S SANTEE TO SAVANNAH OUT 20 NM. .GA...SMALL CRAFT ADVISORY SAVANNAH TO ALTAMAHA SOUND 20 TO 60 NM. RVT/MJR sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 948 AM EST SAT APR 1 2000 PATCHES OF OPAQUE CS WILL CONTINUE TO MOVE THROUGH THE REGION THIS AFTERNOON. HOWEVER...BOTH THE 12Z RUC AND 06Z ETA SHOW ONLY THE 30H MOISTURE ACROSS THE REGION THIS AFTERNOON (EXCEPT SOME 80H MOISTURE AND BELOW...WILL DISCUSS THIS LATER). THERE IS AN INDICATION OF SOME 50H MOISTURE MOVING INTO SOUTHEAST TN BETWEEN 21Z AND 00Z. BKN SC ACROSS NRN GA HAS SPREAD NORTH INTO THE SOUTHERN VALLEY. BOTH THE ETA AND RUC INDICATE THAT THIS MOISTURE AT 80H AND BELOW WILL CONTINUE TO SLIDE NORTHWARD. HOWEVER...THE VISIBLE INDICATES THAT THIS IS A VERY SHALLOW CLOUD LAYER...AND WAS NOT MOVING OVER THE PLATEAU OR MOUNTAINS. WITH ONLY PATCHY CS ABOVE THAT LAYER OF SC... EXPECT THAT IT WILL LIFT AND BECOME A BKN CU FIELD AS WE GO THROUGH THE AFTERNOON. IN GENERAL...WILL UPDATE SOME CLOUD WORDING FOR THE ZONES. INCREASING CLOUDS TOWARD EVENING FOR SW VA AND NE TN...INCREASING CLOUDS FOR THE CENTRAL VALLEY...NORTHERN PLATEAU...SOUTHERN MOUNTAINS... AND PROBABLY MOSTLY CLOUDY FOR SOUTHEAST TN. WITH SOME CLOUD CHANGES...WILL TWEAK A FEW TEMPS ESPECIALLY FOR THE NORTHERN PLATEAU. .MRX... NC...NONE. TN...NONE. VA...NONE. RBP tn AREA FORECAST DISCUSSION...AMENDED NATIONAL WEATHER SERVICE LUBBOCK TX 410 AM CST SAT APR 1 2000 ...AFTER LOOKING AT THE LATEST RUC MODEL DATA WILL MENTION THE POSSIBILITY OF RAIN/SNOW MIX FOR THE NORTHWEST SOUTH PLAINS. KCVS IS REPORTING LIGHT SNOW ATTM. 09Z RUC SHOWS 85H TEMPS GOING BELOW FREEZING IN THE NORTHWEST COUNTIES AND FORECAST SOUNDINGS FOR THIS AREA IS BELOW FREEZING EXCEPT FOR A SHALLOW LAYER NEAR THE SURFACE. WITH TEMPERATURES REMAINING AT OR SLIGHTLY ABOVE FREEZING THIS MORNING AND RELATIVELY WARM GROUND TEMPS DO NOT EXPECT ACCUMULATIONS AT THIS POINT SO WILL NOT ISSUE AN ADVISORY... WATER VAPOR IMAGERY SHOWS UPPER LOW NEAR KPHX AND MOVING SLOWLY SOUTH TOWARD NORTHWEST MEXICO. UPPER AIR ANALYSIS AND WATER VAPOR LOOP SHOWS A SPEED MAX IN THE SUBTROPICAL FLOW THAT MOVED ACROSS NORTHERN CHIHUAHUA THROUGH SOUTHEAST NEW MEXICO SINCE 00Z. THIS SPEED MAX APPEARED TO BACK UPPER FLOW FIELD A BIT WHICH INCREASED THE UPPER LEVEL DIVERGENCE OVER THE SOUTH PLAINS. WIDESPREAD SHOWERS AND THUNDERSTORMS CONTINUE AT THIS HOUR FROM EASTERN NEW MEXICO TO THE PERMIAN BASIN NORTHWARD THROUGH THE SOUTH PLAINS INTO THE TEXAS PANHANDLE AND WESTERN OKLAHOMA. THE ISENTROPIC LIFT IS QUITE STRONG OVER THE REGION ATTM AND SHOULD CONTINUE THROUGH THE MORNING HOURS. COLD FRONT LOCATED ALONG A LINE FROM JUST NORTH OF KSPS TO SOUTH OF KFST AT 09Z. THE FRONT WILL CONTINUE TO SAG SOUTH INTO CENTRAL TEXAS LATER TODAY. AS THE FRONTAL BOUNDARY MOVES FURTHER AWAY FROM OUR REGION...THE ISENTROPIC LIFT IN THE 290-305K LAYER WILL DIMINISH. WILL CONTINUE HIGH POPS FIRST PERIOD DUE TO WIDESPREAD PRECIPITATION THIS MORNING BUT THERE SHOULD BE A NOTICEABLE DECREASE BY THIS AFTERNOON. NOT MUCH IN THE WAY OF DIURNAL RANGE IN TEMPERATURES TODAY. FOR TONIGHT...ETA MODEL DEPICTS ISENTROPIC LIFT INCREASING AGAIN FROM THE SOUTH INTO THE AREA. WILL TAYLOR THE POPS FROM THE LEAST/SLIGHT CHANCE IN THE NORTHWEST TO LIKELY POPS IN THE SOUTHERN LOW ROLLING PLAINS FOR TONIGHT. SLIM CHANCES FOR LIGHT RAIN MAY LINGER INTO THE EARLY MORNING HOURS FOR SUNDAY...OTHERWISE LIFT VANISHES OVER THE SOUTH PLAINS AND EXPECT TEMPERATURES TO REBOUND AS A WEAK TROUGH OF LOW PRESSURE DEVELOPS OVER EASTERN NEW MEXICO AND CLOUDS DECREASE BY AFTERNOON. MODELS ARE FAIRLY SIMILAR SHOWING UPPER LOW NEAR SOUTHEAST ARIZONA AND NORTHWEST MEXICO REGION THROUGH SUNDAY MORNING BEFORE WEAKING AS IT PROGRESSES INTO THE SOUTHERN HIGH PLAINS BY SUNDAY AFTERNOON. A STRONG NORTHERN STREAM SHORT WAVE DIVES OUT OF CANADA TONIGHT AND FORMS A DEEP UPPER LOW OVER THE NORTHERN PLAINS BY SUNDAY AFTERNOON. THE ASSOCIATED COLD FRONT WILL SURGE INTO THE AREA BY MONDAY MORNING WITH TEMPERATURES MONDAY 5-10 DEGREES COOLER THAN SUNDAY. WILL CONTINUE A SLIGHT CHANCE OF RAIN SUNDAY NIGHT/MONDAY MORNING AS CONVERGENCE ALONG FRONT COULD GENERATE LIGHT PRECIP. FRIONA 40/33/62 721 LUBBOCK 45/35/62 942 TULIA 43/34/61 831 BROWNFIELD 46/36/63 842 CHILDRESS 47/38/60 +41 ASPERMONT 51/42/62 +63 .LBB...NONE. TINSLEY tx COASTAL BEND FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 300 AM CST SAT APR 1 2000 MORNING SHOWERS ARE FORMING ALONG A DEVELOPING WARM FRONT CURRENTLY NORTH OF THE ALI-CRP AREA. MSAS MOIST DIV SHOWS GOOD CONVERGENCE IN THE AREA OF THE SHOWERS. RUC GUIDANCE INDICATES THE BOUNDARY WILL LIFT NORTH THROUGH THE MORNING...AND WILL BE A FOCUS FOR RAINFALL TODAY. UPPER LOW CURRENTLY OVER SOUTHERN ARIZONA...AND IS EXPECTED TO REMAIN ALMOST STATIONARY THROUGH SUNDAY MORNING. LOW WILL BEGIN TO LIFT OUT AS IT IS ENTRAINED BACK INTO THE MAIN FLOW. THE RESULT WILL BE A SIGNIFICANT LONGWAVE TROUGH OVER THE CENTRAL U.S. FORCING FROM THE UPPER FEATURE WILL HELP DRIVE A COLD FRONT INTO THE AREA ON MONDAY...WHICH WILL EFFECTIVELY END RAIN CHANCES FOR THE CWA. UNTIL THEN...EXPECT A PRETTY GOOD SHOT FOR RAINFALL ACROSS THE AREA. WITH EVERYTHING SEEMINGLY COMING TOGETHER FOR RAIN OVER THE NEXT THREE DAYS...WILL ADJUST POP GENERALLY UPWARD ON THIS FORECAST. FOR TODAY...WILL GO A HIGHER ON POPS DUE TO THE LIFTING WARM FRONT. AS THE COLD FRONT BOUNDARY MOVE SLOWLY TOWARD US SUNDAY...AMPLE MOISTURE AND LIFT TO BRING WIDESPREAD RAINFALL. FRONT STALLS OVER THE AREA OVERNIGHT ON SUNDAY...PROVIDING FURTHER FOCUS FOR RAINFALL. MONDAY WILL CONTINUE THE TREND...AS OLD COLD FRONT RECEIVES A SECOND SURGE OF COOL AIR...THANKS TO THE DEVELOPING LONGWAVE TROUGH. MODEL SOUNDINGS AS WELL AS PREDICTED WIND AND TEMPERATURE FIELDS INDICATE SEVERE WEATHER IS POSSIBLE THIS WEEKEND. SPC AGREES WITH THIS POSSIBILITY AND HAS PLACED AREA UNDER A SLIGHT RISK OF SVR WX. WILL INVESTIGATE THE POSSIBILITIES FURTHER THIS MORNING AND ISSUE AN HWO TO HIGHLIGHT THREATS. BEYOND MONDAY...WEATHER WILL BE SLIGHTLY COOLER THAN NORMAL...AND GENERALLY PLEASANT. MARINE...A WARM FRONT WILL MOVE THROUGH THE COASTAL WATERS THIS MORNING. THIS WL CAUSE A SUBTLE SHIFT IN THE WINDS TO A MORE SELY DIRECTION. ATTM...I AM NOT EXPECTING SCA CONDITIONS. WL INSTEAD GO WITH SCEC FOR ALL ZONES. THE GRADIENT SHOULD SLOWLY DECREASE TNT AND ESPECIALLY ON SUNDAY AS THE COLD FNT SLIPS SEWD WITH TIME. THE ETA IS A BIT FAST WITH FROPA AND WL OPT FOR THE AVN SOLN INSTEAD WHICH BRINGS THE FNT THROUGH LATE SUNDAY. WL SLOWLY INCREASE CHCS FOR RAIN THROUGH THE FCST PD. IT LOOKS LIKE NUMEROUS SHRAS/TSRAS WL BE POSSIBLE LATE TNT INTO EARLY MONDAY AS ABUNDANT MOISTURE INTERACTS WITH THE FNTL BOUNDARY. THE STRONG COLD FNT ON MONDAY WL PRODUCE ANOTHER ROUND OF PCPN BEFORE CLEARING THINGS OUT. SCA CONDITIONS APPEAR LKLY ON MONDAY WITH THIS FNT. JMC.84.SYN MB.80.MES PRELIM NUMS... CRP TT 081/070 081/065 078 5685 VCT TT 080/068 081/063 078 6685 LRD TT 084/068 085/064 080 5675 .CRP...NONE. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 250 PM CST SAT APR 1 2000 FORECAST QUANDARIES...POTENTIAL FOR HEAVY RAINFALL EVENT SUNDAY INTO MONDAY. CURRENT ASOS/AWOS OBSERVATIONS...REGIONAL SATELLITE IMAGERY... UPPER AIR RUC/CHART...AND LAPS/SURFACE ANALYSES SHOWING MAIN RIDGING AXIS SURFACE AND ALOFT ACROSS THE CENTRAL ATLANTIC STATES. WITH RIDGING MOVEMENT EASTWARD...INFLUX OF MID LEVEL MOISTURE IN PROGRESSIVE SWLY FLOW OCCURRING AS UPPER LEVEL LOW "DEEPENS" THROUGHOUT THE LOWER MS VALLEY AREA. PREVAILING CWA AIRMASS SUPPORTING TEMPERATURES IN THE 70S...DEWPOINTS IN THE 5OS...WITH SOUTHERLY SURFACE FLOW. 12Z SAT REGIONAL MODEL RUNS INITIALIZATION SIMILAR. HOWEVER... AGREE WITH LATEST MODEL DIAGNOSTIC DISCUSSION THAT AN AVN/ETA SOLUTION FOR PROGGED EVOLUTION THROUGH 00Z TUE PREFERRED DUE TO NGM "ROBUST" ENERGY AMPLIFICATION TRENDS. WITH THIS IN MIND...EXPECT SURFACE LOW PRESSURE DEVELOPMENT ACROSS THE CENTRAL MID MS VALLEY BY 06Z SUN...MOVING NE INTO CENTRAL OHIO AROUND 18Z SUN. AS A RESULT...THIS WILL "DRAG" A COLD FRONT SLOWLY THROUGH THE REGION DURING SUN AFTERNOON. ANTICIPATE ANOTHER COLD FRONTAL PASSAGE AFTER 12Z MON IN CORRELATION WITH UPPER MS VALLEY SURFACE LOW INTENSIFICATION AND MOVEMENT NE INTO LAKE SUPERIOR BY 00Z TUE. UPPER LEVEL LOW WILL FORM ACROSS NORTHERN MIDWEST BY 00Z MON WITH TROUGH ELONGATION AND MOVEMENT EASTWARD THE CENTRAL U.S. BY 00Z TUE. LOOK FOR CLOUDY SKIES AND RAINFALL TO BE PREVALENT SKY CONDITIONS THROUGHOUT MOST OF FORECAST PERIOD. LOOK FOR RAINFALL ACTIVITY TO BECOME LIKELY WEST AND MIDDLE PORTIONS BY EARLY EVENING AND ALL AREAS AFTER MIDNIGHT. IN AGREEMENT WITH DAY ONE EXCESSIVE RAINFALL POTENTIAL OUTLOOK THAT HIGH PW VALUES...AS HIGH AS 1.71 INCHES IN CWA/SOUTHERN PORTIONS DURING SUNDAY AFTERNOON... ALONG WITH SHORTWAVE PASSAGES IN THE UPPER LEVEL FLOW WILL SUPPORT CONVECTIVE HEAVY RAINS ALONG WHAT WILL BE A SLOW MOVING FRONTAL SYSTEM INTO SUNDAY EVENING AND MON. BEST ATMOSPHERIC DYNAMICS ASSOCIATED WITH TS DEVELOPMENT SHOULD OCCUR AFTER 12Z SUN. UNDERSTAND REASONING OF DAY 2 CONVECTIVE OUTLOOK SLIGHT RISK CRITERIA..BUT MODEL SOUNDINGS SHOWING SWEAT VALUES AROUND 300 AT 12Z SUN... BUT NOT AS MUCH POTENTIAL LATER DURING THE DAY. WILL MENTION STRONG TS SOUTH SUNDAY MORNING. LATER SHIFTS AND MODEL RUNS WILL HAVE TO BE MONITORED CAREFULLY TO SEE IF POTENTIAL INCREASES FOR FLASH FLOODING OCCURS. WILL MENTION ONLY HEAVY RAINFALL AT THIS TIME. WITH SLOW MOVEMENT OF FRONTAL SYSTEM...AIRMASS WILL CONTINUE TO REMAIN MOIST AS SECOND FRONTAL SYSTEM APPROACHES FROM THE UPPER MIDWEST. RAINFALL SUNDAY NIGHT INTO MONDAY COULD PROVIDE ADDITIONAL FLOODING PROBLEMS IF GROUND IS TOTALLY SATURATED FROM SUNDAY RAINFALL. TEMPERATURES...WILL COMPROMISE BETWEEN AVN FAN/NGM MOS LOWS DURING PERIOD. WITH OVERCAST SKIES BOTH SUNDAY AND MONDAY WITH COPIOUS RAINFALL...WILL TREND CLOSER TO AVN FAN/ETA IN HOUSE BOUNDARY TEMPERATURE SCHEME VALUES. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 058/070/058/068 9++7 CSV 055/067/055/065 9++8 .BNA...NONE. 14 JBW tn