EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 844 PM EST SAT MAR 11 2000 CURRENTLY...IR SATELLITE IMAGERY INDICATES PRE-FRONTAL CONVECTION MOVING EASTWARD THROUGH THE FLORIDA PANHANDLE. TEMPERATURES AT 8 PM ARE IN THE LOWER TO MID 70S ACROSS THE FORECAST AREA. DEWPOINTS ARE RANGING FROM THE MID 50S NORTH TO THE MID 60S SOUTH. DISCUSSION...THE ALMOST SOLID LINE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE DOWN THE THE FLORIDA PENINSULA AND ENTER THE NORTHERN PORTION OF THE FORECAST AREA AROUND MIDNIGHT. THE CONVECTION WILL WEAKEN AS IT MOVES INTO DRIER AND MORE STABLE AIR...ESPECIALLY ON THE EASTERN HALF OF THE PENINSULA. 23Z RUC MODEL SHOWS LIFTED INDICES AT 06Z ON THE EASTERN HALF OF THE FLORIDA PENINSULA AT -2 AND INCREASING TO -5 ALONG THE WESTERN COAST. 00Z TBW SOUNDING SHOWS -3.5 LIFTED INDEX. EVEN THOUGH THE LINE OF CONVECTION WILL BE AFFECTED BY MORE STABLE AIR AS IT MOVES THROUGH THE FORECAST AREA...CURRENT POPS IN ZONE FORECAST LOOK A LITTLE TOO LOW...SO WILL BUMP THEM UP TO 40 PERCENT. MARINE...LATEST 4 HOUR TREND AT BUOY 41009 SHOWS SEAS BUILDING TO OVER 6 FEET. WILL MONITOR THE COASTAL WATERS CAREFULLY THE NEXT COUPLE OF HOURS TO SEE IF SMALL CRAFT ADVISORY IS NEEDED. .MLB...NONE. JMB fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 220 PM EST SAT MAR 11 2000 CURRENTLY: CWA IS UNDER SEVERE THUNDERSTORM WATCH UNTIL 22Z. LINE OF CONVECTION CROSSING APALACHICOLA RIVER AT THIS TIME....WITH MAIN CONCERN DAMAGING WINDS. SEE SPC GUIDANCE ON SEVERE TSTM WATCH #91 FOR MORE DETAILS. FORECAST: 17Z RUC PROGS COLD FRONT TO REACH AQQ-ABY LINE BY 03Z AS UPPER SHORTWAVE TRANSLATES E TO TN VALLEY. MOIST FLUX DIVERGENCE PROGGED TO HAVE SPREAD OVER MOST OF CWA BY SHORTLY AFTER MIDNIGHT ...SO WILL TIME END OF PCPN ACCORDINGLY FOR ERN ZONES. MUCH OF WRN CWA SHOULD SEE PCPN ENDING BY THIS EVENING...SO WILL HAVE LEFTOVER POPS FOR SOME AREAS FOR THE FIRST PERIOD. UPPER SHORTWAVE TROUGH TO SHEAR NE OVER MID-ATLANTIC OVERNIGHT THROUGH SUNDAY EVENING...LEAVING CWA IN MORE ZONAL FLOW ALOFT. AT THE SURFACE...STRONG NW FLOW WILL SPREAD ACROSS THE CWA OVERNIGHT AS HIGH PRESSURE BUILDS INTO THE CWA BEHIND THE FRONT. SURFACE HIGH PRESSURE TO DRIFT TO CAROLINAS THROUGH MONDAY...RESULTING IN DRY OFFSHORE FLOW CONDITIONS. WILL NOT DEVIATE FAR FROM GUIDANCE NUMBERS. MARINE: NW FLOW BEHIND FRONT SHOULD WARRANT A SMALL CRAFT ADVISORY TONIGHT. PRESSURE GRADIENT SHOULD LOOSEN DURING THE DAY SUNDAY... ALLOWING WINDS TO SLACKEN BELOW SCA CRITERIA. EXTENDED (MONDAY NIGHT THROUGH THURSDAY): MRF ADVERTISES SRN STREAM SHORTWAVE TROUGH AND ASSOCIATED INVERTED SURFACE TROUGH TO CROSS THE CWA WEDNESDAY. WILL MENTION SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY WITH IMPROVING CONDITIONS THURSDAY. ALL INPUT IS WELCOME. PRELIMINARY NUMBERS... TLH 047/065 035/069 4000 PFN 049/063 045/065 2000 DHN 045/059 037/064 2000 ABY 046/061 036/065 4000 VLD 050/062 035/068 5000 .TLH... AL...SEVERE TSTM WATCH TIL 4 PM CST. GA...SEVERE TSTM WATCH TIL 5 PM EST. FL...SEVERE TSTM WATCH TIL 5 PM EST. SCA TNGT SUWANNEE RIVER TO DESTIN OUT TO 60 NM. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 950 AM EST SAT MAR 11 2000 AT 14 UTC AN EASTWARD-MOVING COLD FRONT EXTENDED FROM CENTRAL TENNESSEE TO SOUTHEAST LOUISIANA. AHEAD OF THIS FRONT SEVERE THUNDERSTORMS WERE OCCURRING JUST NORTH OF OUR COUNTY WARNING AREA...WHILE NON-SEVERE STORMS WERE DEVELOPING ACROSS WESTERN PORTIONS OF OUR AREA. THESE STORMS WERE FORMING ALONG A STRONG MESOSCALE THETA-E GRADIENT WITH HIGH SURFACE MOISTURE FLUX CONVERGENCE VALUES. THE 12 UTC TLH SOUNDING WAS CONVECTIVELY UNSTABLE WITH A LOW WET BULB ZERO LEVEL AND FAIRLY STEEP 700-500 MB LAPSE RATES. WILL BE ON THE LOOKOUT FOR SUDDEN DRYING AT THE SURFACE TO SEE IF WE BREAK THE CAP THIS AFTERNOON. BASED ON CURRENT TRENDS...SOUNDING DATA...AND THE LATEST RUC...LOOKS LIKE LARGE HAIL AND DAMAGING STRAIGHT LINE WINDS (ASSOCIATED WITH BOW ECHOES) WILL BE THE PRIMARY THREAT FOR OUR AREA. CURRENT ZONES LOOK GOOD AND WILL ONLY MAKE COSMETIC CHANGES. LATEST MARINE OBS SHOW ENTIRE AREA BELOW SCA CRITERIA...BUT I AM RELUCTANT TO TAKE THE ADVISORY DOWN JUST AFTER IT HAS BEEN ISSUED. WILL TAKE A CLOSER LOOK THIS AFTERNOON. .TLH... AL...NONE. GA...NONE. FL...SCA AQQ-DESTIN. FOURNIER fl EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 938 AM EST SAT MAR 11 2000 CURRENTLY...SOUTHERLY FLOW ADVECTING MID 60S DEW POINTS ACROSS THE AREA IN ADVANCE OF FRONTAL SYSTEM. PRECIPITABLE WATER HAS INCREASED SLIGHTLY TO A LITTLE OVER AN INCH AND THERE WAS A LITTLE BIT OF LOW LEVEL SHEAR. WATER VAPOR LOOP AND RUC ANALYSIS SHOW JET STREAK ACROSS THE CENTRAL PENINSULA. AREA OF SHOWERS OVER THE WARM GULF STREAM LINE UP WELL WITH LEFT EXIT REGION OF THIS FEATURE. FORECAST...MODELS ALL SHOW JET STREAK MOVING SOUTHEAST OF THE AREA BY THE TIME OF MAX HEATING WITH LOW LEVEL SHEAR WEAKENING. AREA OF PREFRONTAL CONVECTION WHICH WILL LIKELY BE ENHANCED BY RIGHT REAR QUADRANT OF POLAR JET WILL STAY TO OUR NORTHWEST. FORECAST SOUNDINGS SHOW SOME POSITIVE AREA BUT WITH CENTRAL FLORIDA BEING BETWEEN LARGE SCALE FORCING FEATURES AND NO EAST COAST SEA BREEZE FORMING...FIGURE THAT ANY AFTERNOON CELLS THAT FORM WILL HAVE LOW COVERAGE. HENCE THE CURRENT FORECAST WITH A SMALL CHANCE OF CONVECTION LATE THIS AFTERNOON AND A SLIGHTLY GREATER CHANCE THIS EVENING STILL LOOKS GOOD. MAY HAVE TO MAKE SOME MINOR WORDING CHANGES TO ACCOUNT FOR THE FEW CELLS THAT ARE CURRENTLY OCCURRING ...BUT DO NOT FORESEE ANY SIGNIFICANT CHANGES. MARINE...WINDS ARE WITHIN BOUNDS OF CURRENT FORECAST...ALTHOUGH THE DIRECTION IS SOUTHERLY AND THE 12Z ETA CONTINUES THIS. PLAN TO KEEP AN EXERCISE CAUTION STATEMENT. .MLB...NONE. LASCODY fl AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 915 PM CST SAT MAR 11 2000 LATEST DATA AND MODEL GUIDNCE...INCLUDG RUC AND NEW ETA...SHOW FCST ON TARGET WITH NO UPDATES NEEDED NOW. TRANSLATED...LOOKS LIKE THIS SYS IS FOR REAL AND DAY FCSTR WAS RIGHT TO GO HIR THAN GUIDNCE POPS. PCPN SHUD REALLY BLOOM (A PUN IN THIS OFFICE) AFTR MIDNGT. SOME AREAS MAY START AS A LTL -RA OR -FZRA AS FCST BUT COOLNG SHUD QUICKLY CHANGE PCPN TO SNW. THIS CUD EVEN TURN OUT TO REQUIRE AND ADVSY SOMEWHERE WITH EVEN ETA SHOWNG DECNT LIFT...BUT THERE IS SOME DRY AIR TO OVRCOME FIRST. AS MMENTND FCST LOOKS GOOD FOR NOW. .FSD...NONE WILLIAMS sd AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 1005 AM CST SAT MAR 11 2000 MAIN CONCERN THIS MORNING DEALS WITH TEMPS AND CLOUDS. EXTENSIVE CLOUD SHIELD SLIDING SOUTH OUT OF NORTH DAKOTA...BUT SAT IMAGE SHOWS THAT IT IS THINNING AS IT GOES. NEW ETA/RUC CONCUR ON WINDS TURNING MORE TO THE EAST AS NEXT LOW DROPS DOWN FRONT RANGE LATER TONIGHT. AS CLOUDS THIN...SHOULD SEE MORE CLOUDS SLIDING OVER CWA IN ADVANCE OF NEXT SYSTEM. NEW ETA SFC TEMPS...AND FLP TEMPS...SHOW THAT HIGHS MIGHT NEED TO BE DROPPED A TOUCH TODAY. WITH ONLY DIM SUNSHINE TODAY AND WEAK WINDS...WILL DROP TEMPS ALL AREAS A NOTCH AND GO MOSTLY CLOUDY. ALSO PLAYED WITH THE WINDS A TAD. UPDATES OUT SHORTLY. .ABR...NONE. HINTZ sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 835 PM CST SAT MAR 11 2000 STRONG BAROCLINIC ZONE ACROSS MINNESOTA THIS SATURDAY EVENING WITH NEW ETA RUN CARRYING SHORT WAVE ENERGY ACROSS FAR SOUTHWEST AND WEST CENTRAL MINNESOTA LATE TONIGHT INTO MIDDAY SUNDAY. ELONGATED POTENTIAL VORTICITY MAX PASSES ACROSS IOWA AFTER DAYBREAK SUNDAY. LATEST RUC MOVES MOISTURE INTO SOUTHWEST MINNESOTA WITH ABOUT THE SAME SPEED AND ORIENTATION OF ETA TOO. LOOKING OVER CURRENT FORECAST ZONES I FIND LITTLE IF ANY MEANINGFUL CHANGES TO MAKE SO I WON'T CHANGE A THING. .MSP...NONE. WET mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 325 AM EST SUN MAR 12 2000 RUNNING A BIT LATE... SHORT TERM...BROAD SURFACE LOW CURRENTLY OVER CENTRAL PA WITH WARM FRONT CURRENTLY EXTENDING FROM SE MASS TO SOUTH FORK OF LONG ISLAND TO CENTRAL NJ. LOW IN THE NCEP MODELS TRACKS TO THE RIGHT OF THIS POSITION. LATEST RUC RUN HAS LOW GOING INTO CENTRAL NEW YORK THIS MORNING. THE 06Z ETA HAS THIS TOO...BUT REDEVELOPS AND STARTS TO ORGANIZE THE LOW OVER LONG ISLAND AT 15Z. IT THEN SHOOTS NORTHEAST AS THE UPPER TROF LIFT AND WEAKENS. WITH THE NORTHEAST FLOW OVER THE REGION HAVING WEAKENED SIGNIFICANTLY AND THE LOW PASSING TO THE WEST...WILL FORECAST US GOING INTO THE WARM SECTOR SHORTLY. STONY BROOK MM5 12KM VERSION HAS THIS RESOLVED NICELY AS WELL. INTERESTINGLY...THE 4KM RUN WARMS THE CITY UP TOWARDS 60. BASED ON THE TRACK OF LOW AND BLOCK ISLAND JUST JUMPING TO 52 THIS HOUR...WILL BUMP UP TEMPS A BIT AND TRY TO REDEEM MYSELF AS YESTERDAYS BUST ON THE WARM FRONT TIMING AND TEMPS. WILL KEEP POPS HIGH AND KEEP THE TSTMS. WINDS GO SOUTHWEST AND THEN WORK AROUND EVENTUALLY TO NW. NO OTHER CHANGES PLANNED FOR THE FCST. MARINE...WILL KEEP THE SCA. WINDS SHOULD GET TO THE 20 TO 25 KT RANGE BY EVENING. SEAS CURRENTLY AROUND 6 FT ON THE OCEAN. NO NEW WAVEWATCH III DATA OR WAM...BUT 12Z DATA INDICATED THAT SEAS COME UP BETWEEN NOW AND 12Z. DO HAVE ANY DATA TO SUPPORT THIS SO WILL GO WITH A 5 TO 7 FOOT RANGE. COASTAL FLOODING...SENT FINAL CFW STATEMENT. DON/T EXPECT ANY PROBLEMS. .OKX...SMALL CRAFT ADVISORY...CSTL WATERS...LI SOUND AND NY HARBOR...ANZ330-335-338-350-353-355. TONGUE ny WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 245 AM MST SUN MAR 12 2000 SHORT TERM MODELS ALL APPEAR TO BE ON THE SAME PAGE THIS MORNING. BROAD LOW AMPLITUDE RIDGE OVER EASTERN PACIFIC CREATING A NORTHWESTLY FLOW INTO CWA WITH SEVERAL FAST MOVING EMBEDDED DISTURBANCES. NGM STILL TRACKING ACTIVITY SLIGHTLY FURTHER NORTH THAN AVN OR ETA. HOWEVER...ETA AND AVN PERFORMED BETTER YESTERDAY CONSIDERING PRECIP CURRENTLY OCCURRING IN NORTHERN PORTION OF CWA...SO WILL CONTINUE TO LEAN THEIR WAY. PRECIP RESULT OF ONE DISTURBANCE PASSING OVER CWA THIS MORNING. ETA/NGM/AVN ALL PULL THIS TO OUR EAST BY NOON WHILE RUC HANGS ON TILL EARLY AFTERNOON. SATELLITE IR IMAGES SUGGESTING CIRCULATION CENTER OVER WESTERN UT AT THIS TIME. SO... WILL HANG ON TO MOSTLY CLOUDY SKIES WITH SCATTERED SHOWERS OVER THE MOUNTAINS THROUGH THE MORNING. CROSS SECTIONS SHOW AIR MASS QUICKLY DRYING BEHIND THIS WAVE WITH SUBSIDENCE SO BELIEVE CLOUDS SHOULD DECREASE THROUGH THE AFTERNOON. LOW PRESSURE SYSTEM CURRENTLY BUILDING OVER GULF OF AK CONTINUES TO ENCOURAGE AMPLIFICATION OF WEST COAST RIDGE MONDAY CONTINUING NORTHWEST FLOW ALOFT OVER WESTERN U.S. ...BUT WITH A WEAK SPLIT IN FLOW OVER CWA. WITH THIS SPLIT NEXT COUPLE OF WAVES TO BE STEERED JUST NORTH AND SOUTH OF CWA...COULD BE CLOSE ENOUGH TO CREATE SOME WIDELY SCATTERED SHOWERS...MAINLY OVER NORTHERN MOUNTAINS LATE MONDAY. GUIDANCE PERFORMING PRETTY WELL AND WILL DEVIATE ONLY A COUPLE DEGREES. FOR EXTENDED...GULF OF AK LOW BEGINS PUSHING INLAND TUESDAY AND ENCOURAGES A BUCKLING OF THE PRESSURE PATTERN WITH A LOW PRESSURE TROUGH DEVELOPING FROM ND TO TX BY WEDNESDAY. FLOW INTO CWA BECOMES MORE NORTHERLY AND ONE IMPULSE WITH LOW FORECAST TO TRACK OVER CWA. CURRENT MRF SHOWING GOOD CONTINUITY WITH PREVIOUS RUN UP TO END OF EXTENDED PERIOD. ONLY NOTABLE DIFFERENCE IS CURRENT RUN DEVELOPING TROUGH SLIGHTLY FURTHER WEST THAN PREVIOUS RUN. ECMWF HAS VERY SIMILAR SOLUTION WHILE UKMET CONTINUES AS OUTLIER WITH BIG TIMING DIFFERENCES. WILL STICK CLOSE TO MRF SOLUTION AND MAKE A FEW ADJUSTMENTS TO EXTENDED...MAINLY IN TIMING OF PRECIP CHANCES. WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN A NORMAL LEVEL OF WEATHER AWARENESS TODAY. .GJT...NONE. GL co EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 930 AM EST SUN MAR 12 2000 CURRENTLY...SURFACE THETA E GRADIENT CORRESPONDS RATHER WELL WITH WIND SHIFT TO THE NORTHWEST...WHICH PLACES FRONT FROM ABOUT TITUSVILLE TO ORLANDO TO TAMPA. THIS IS PICKED UP ON VERY WELL BY LATEST RUC MODEL WHICH PUSHES FRONT TO ABOUT VERO BEACH BY 18Z. THIS WARRANTS A CONTINUATION OF SMALL POPS FOR THE SOUTHERN THREE COUNTIES...ESPECIALLY GIVEN LATEST RADAR TRENDS. LOW CLOUDS WERE PUSHING STEADILY SOUTH BEHIND THE FRONT. IN THE LATE MORNING UPDATE...WILL BE ABLE TO REMOVE POPS AND UPGRADE SKY CONDITIONS TO (BECOMING) MOSTLY SUNNY FOR THE REMAINDER OF THE AREA. MARINE...PRE FRONTAL GRADIENT IS VERY WEAK BUT BEHIND THE FRONT THE WINDS ARE AT SMALL CRAFT LEVELS. MESO ETA AND LATEST RUC SHOW THIS TIGHTER GRADIENT MAINLY AFFECTING THE NORTHERN LEG. WILL CONTINUE THE EXERCISE CAUTION STATEMENT...EVEN IN THE SOUTH LEG...BUT WORD THAT SEGMENT FOR INCREASING WINDS MAINLY NORTH PART. .MLB...FIRE WEATHER WATCH FOR VOLUSIA...LAKE...ORANGE...SEMINOLE COUNTIES. LASCODY fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBUQUERQUE NM 300 AM MST SUN MAR 12 2000 W-NW FLOW ALOFT TODAY WITH A COUPLE OF WEAK VORT MAXES PASSING JUST NORTH OF THE BORDER. ONE SUCH FEATURE MOVING INTO SW KANSAS AND OF LITTLE CONSEQUENCE. ANOTHER ONE FARTHER UPSTREAM IN VICINITY OF ERN UTAH/WRN COLORADO...AND LATEST RUC/MESO ETA SHOW THIS VORT CENTER CROSSING THE NORTHEAST CORNER BETWEEN 18-21Z. LITTLE TO SUPPORT POPS WITH ONLY WEAK UVV AND MEAN RH/S OF 50-60% PROGGED ACROSS THE FAR NORTH. WILL KEEP WITH PARTLY CLOUDY SKIES. REMAINDER OF THE AREA WILL SEE PLENTY OF SUNSHINE WITH OCCASIONAL HIGH CLOUDS AND MILD TEMPS. 850 MB TEMPS WARM 5-10 DEGREES OVER SATURDAY ACROSS MUCH OF THE EAST. WIND SHIFT EVENTUALLY MOVING INTO THE NORTHEAST PLAINS LATE IN DAY/EARLY EVENING AS ABOVE SHORT WAVE HEADS EAST. PERIODS OF HIGH CLOUDS TONIGHT WITH CONTINUED WEST-NORTHWEST FLOW. ON MONDAY...ANOTHER SHORT-WAVE TROUGH DEVELOPS OVER ARIZONA THEN TRANSLATES SEWD MON NIGHT AND TUE. NGM/AVN SHOWING MORE CURVATURE TO THIS TROUGH THAN ETA...BUT POSITIVE TILT AND STRETCHED OUT VORTICITY PATTERN WOULD SUGGEST WEAK LIFT FOR AN INCREASE IN MID/HIGH CLOUDS AREAWIDE BEGINNING LATE MONDAY. KEY WILL BE HOW STRONG THE LOW LEVEL UPSLOPE FLOW GETS FROM THE CENTRAL MOUNTAINS EASTWARD MON NIGHT/TUE AS THE SHORT WAVE APPROACHES. WILL GO WITH LOW POPS FOR THE EAST MONDAY NIGHT ANTICIPATING ENOUGH MOISTURE RETURN AND DESTABILIZATION OF THE AIR MASS. WILL CONTINUE CHANCE POPS FOR OUR SE ZONES ON TUESDAY...OTHERWISE DRIER AIR SPREADING INTO THE NORTHWEST. LATEST MRF SUGGESTS ANOTHER SHORT WAVE DROPPING DOWN IN THE NORTHWEST FLOW FOR WED PM...CLEARING THE AREA THU MORNING. AGAIN BEST CHANCE FOR ANY PRECIP WOULD BE ACROSS THE SOUTHEAST WED. LOOKS BREEZY TO LOCALLY WINDY WED AND THU. ABQ AB 066/037 063/038 061 41000 SAF AB 062/032 058/032 057 4100- TCC AB 068/036 055/034 060 4100- KJ .ABQ...NONE. nm FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 841 PM CST SAT MAR 11 2000 0Z SFC ANALYSIS SHOWS SFC LOW OVER E CENTRAL WY WHICH IS IN GOOD AGREEMENT WITH NEW RUC AND 12Z AVN/ETA AND NEW 0Z ETA. THESE MODELS TAKE SFC LOW ESE INTO CENTRAL NEBRASKA BY 12Z SUNDAY WHILE CONTINUING TO BUILD HIGH PRESSURE INTO THE REGION OVERNIGHT. ETA BRINGS IN WEAK AREA OF 7H UVV/S INTO FAR SW ZONES BEGINNING AROUND 6Z AND CONTINUING UNTIL AFTER 12Z THIS AM...AND THIS AREA CURRENTLY REFLECTS LOCATION OF LIGHT SNOW FALLING OVER WESTERN AND CENTRAL ND. 285K ISENTROPIC LIFT ALSO HIGHLIGHTS THIS AREA AT 0Z...BUT DOES NOT BRING THIS LIFT INTO THE SW FA RATHER INSTEAD SHOWS WEAK DOWNGLIDE. WHILE NEW ETA INDICATES MOST OF SW ZONES SHOULD NOT GET SNOW TONIGHT...SINCE CURRENT FORECAST ONLY CALLS FOR A 30 POP...WILL NOT MAKE ANY ADJUSTMENTS TO THIS. WILL ADJUST WORDING TO REFLECT CLOUD COVER MOVING INTO REGION THIS EVENING. WITH SLIGHTLY DRIER AIR IN THE BOUNDARY LAYER MOVING IN ON NORTHERLY FLOW THE DIMINISHED RADIATIONAL COOLING TO BE OFFSET BY THIS THUS CURRENT TEMPERATURE FORECASTS LOOK ON TRACK. .FGF...NONE. RJT nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 1000 AM EST SUN MAR 12 2000 HI PRES CONTINUES TO SLO BLD INTO SOUTH CAROLINA LATE THIS AM FROM THE MID MS VLY. CDFNT NOW WL OFSHR BUT TIGHT PRES GRAD STILL REMAINS. GRAD WL RELAX LATER TDA BUT SFC WNDS WL STAY UP IN THE MEANTIME. GD CAA TDA WL KEEP TEMPS IN CHECK. CAE FCST SOUNDINGS ON ETA...MESOETA...AND RUC...KEEP FCST MAXES IN LWR 60S WITH LAMP GUIDANCE SHOWING MID 50S FOR CAE AND UPPER 50S FOR AGS. CURRENT FCST TEMPS LUK REASONABLE SO DO NOT PLAN TO CHANGE ATTM. SOME COLD AIR STATOCU ALREADY DVLPG OVR AREA NOW SO MOSTLY SUNNY STILL LUKS GD. .CAE...WIND ADVISORY FOR AREA LAKES THIS AFTERNOON SCZ015-016-018-020-021-022-025>031-035>038-041-GAZ040-063>065-077 FREEZE WARNING TONIGHT SCZ015-016-018-020>023-025>028-030-GAZ040-063>065 BC sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 1108 AM CST SUN MAR 12 2000 STLT IMAGERY SHOWS SHRT WV THRU UPR MO RVR VLY GETTING READY TO DROP INTO IA. RADAR CURRENTLY HAS PCPN ACRS WRN FA WHICH IS MAINLY VIRGA OR SPRINKLES FM HIGHWAY 30 S. TO THE N SNW CONTD WITH VSBYS OCCASIONALLY BLO 1/SSM. CALLS ARND INDC THAT SOME MELING IS OCCURRING WITH ACCUMS LESS THAN AN INCH HWVR SO WE MAY SEE ARND AN INCH BY LATE AFTN IN THOSE AREAS. EVEN THOUGH MSTR IS LTD...THIS PCPN HAS DVLPD IN NICE ISENT LIFT WITH FBY PROFILER SHOWING H85 FLOW OF 35KTS AHD OF SHRT WV. DEFORMATION ZN PCPN STILL WELL N OF FA BUT RADAR MOSAIC IS SHOWING SOME SIGNS OF IT DROPPING SWD WITH SHRT WV SO WL KEEP MENTION GOING IN EVEN FCST BUT CONFIDENCE DMSHG ATTM. 16Z SFC ANLYS PLACES LOW JUST NW OF KOFK AND 15Z RUC KEEPS LOW JUST W OF FA BY 00Z SO ADJUSTED TEMPS AND WNDS ACCORDINGLY. .DSM...NONE SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 255 PM CST SUN MAR 12 2000 ...NW FLOW WITH TIMING OF WAVES CONTINUES MAIN PROBLEM... FIRST WAVE EMERGING FROM THE ROCKIES THIS EVENING PER RUCII. THIS APPEARS A BIT STRONGER ON THE RUCII THAN OTHER MODELS SHOW. PERHAPS BECAUSE DNR WAS MISSING UPPER AIR THIS MRNG...AND SHORT WAVELENGTH OF FAST MOVING WAVES DEPENDENT ON GOOD UA CAPTURE...THEN THERE IS SOME EXPLANATION WHY MODELS NOT DOING TOO WELL WITH THIS ROCKIES WAVE THIS EVENING. THEREFORE...BASED ON SATELLITE AND RUCII...WILL MENTION A FEW RW-- THIS EVENING THEN CLEARING AS LIFT DECREASES LATER TONIGHT AND WAVE PASSES BY. NOTHING MUCH ON MONDAY BUT WILL CONTINUE THE PARTLY CLOUDY FORECAST FOR PHANTOM CLOUDS THAT OFTEN SHOW UP IN THIS NW FLOW REGIME. BETTER GRASP OF SITUATION LATE MONDAY NIGHT INTO TUESDAY. A MORE SGFNT BUT STILL ONLY MODERATE STRENGTH SHORT WAVE MOVES INTO THE AREA. AVM HAS THIS WAVE DIVING INTO/THRU KS DURING THE DAY TUESDAY. CURRENT EFP HAS SOME MENTION OF SHOWERS...AND LOWER POPS REFLECTED IN LATEST GUIDANCE TOO. THEREFORE...WILL CONTINUE MENTION OF SHWRS ON TUESDAY...BUT WILL CONFINE THEM TO THE MRNG...AS APPEARS LIFT/WAVE WILL MV THRU BY AFTN RETURNING SUNSHINE TO THE AREA. TEMPERATURES APPEAR TO RECOVER NICELY PER H850 THERMAL PATTERN TUESDAY AFTERNOON. .TOP...NONE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 140 AM EST SUN MAR 12 2000 RADAR AND SATELLITE LOOPS DEPICT AN IMPROVING TREND ACROSS CWA EARLY THIS MORNING. LAST OF THE -SN JUST ABOUT TO SLIDE TO THE EAST OF CWA...WITH KDTX 88D INDICATING A NARROW BAND OF FLURRIES OR FZDZ BEFORE PRECIP COMPLETELY ENDS. WILL HAVE -SN TAPERING TO FLURRIES AND FZDZ BEFORE ENDING FOR STRING OF EASTERN ZONES FROM PHN TO TTF. TO THE NORTH...CLEARING PROGRESSING SOUTHWARD PER SATELLITE IMAGERY. RUC INDICATES THIS CLEARING TO MAKE STEADY PROGRESS THROUGH THE NIGHT SO WILL BE UPDATING ALL OTHER ZONES TO ACCOUNT FOR IMPROVING SKY CONDITIONS. WILL ALSO LOWER WIND SPEEDS PTK AND ADG ZONES. OKEEFE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 950 AM EST SUN MAR 12 2000 LOW TEMPS THIS MORNING AND 850 MB PLOTS SHOW THAT THE AIRMASS IS SEVERAL DEGREES COLDER THAN MODELS INDICATED WOULD OCCUR. W-NW LOW LEVEL WINDS ARE INDEED PRODUCING SNOW SHOWERS IN THE SMOKY AND NE MTNS...WITH A DUSTING TO AS MUCH AS 1/2 INCH REPORTED THUS FAR. FLURRIES ALSO OCCURRING FROM CENTRAL VALLEY NE. LATEST RUC MODEL DOES INDICATE 925-850 MB LAYER STAYING VERY SATURATED INTO THE AFTN OVER SWRN VA/EXTRM NE TN...AND CONTINUED UPSLOPE FLOW. VERY COLD TEMPS ALOFT (-25 DEG C AT 500 MB) WITH MESOETA CAPES HOLDING AROUND 50 J/KG THIS AFTN. THUS...WILL PROBABLY KEEP SNOW SHOWERS IN FOR MTN ZONES...EXCEPT SE TN AND CHEROKEE/CLAY COUNTIES. PROBABILITIES IN THE CHANCE CATEGORY SEEM APPLICABLE...SINCE ANY ACCUMULATIONS SHOULD BE LIMITED TO WRN SLOPES. RAPID CLEARING NOTED EARLIER ON SATELLITE PICS HAS COME TO A SCREECHING HALT...ALTHOUGH THE SEQUATCHIE AND SOUTHERN VALLEY COUNTIES HAVE EXPERIENCED CONSIDERABLE CLEARING. DOWNSLOPING EFFECT OF W-NW WINDS AND SUNSHINE THOSE AREAS...WHILE ELSEWHERE I AM CONSIDERING LOWERING MAX TEMP FORECAST BY AT LEAST ONE CATEGORY. UPDATES TO ZONES WILL FOLLOW BY 1030 AM EST. .MRX... NC...NONE. TN...NONE. VA...NONE. TG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1152 AM CST SUN MAR 12 2000 LATEST SATELLITE/RADAR IMAGERY LOOPS SHOWING DEFORMATION AREA AND ASSOCIATED SNOW SETTING UP ACROSS SOUTHERN MINNESOTA. TRANSLATION OF THIS WILL MOVE IT ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST WISCONSIN. LAPS SOUNDINGS UNDERSCORING THE DIFFICULTY THE SNOW IS HAVING OVERCOMING THE LOW LEVEL DRY AIR. ALL 12Z MODELS... 15Z RUC AND UPSTREAM CONDITIONS STILL INDICATE ENOUGH FORCING TO SUGGEST THIS WILL EVENTUALLY HAPPEN. WILL HAVE TO ADJUST TEMPERATURES UPWARD AHEAD OF THE SYSTEM AND DELAY ONSET OF PRECIPITATION AS A RESULT. .LSE...NONE. KRC wi