EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 410 AM PST TUE FEB 8 2000 MOIST SOUTHERLY FLOW ALOFT WILL SPREAD CONSIDERABLE CLOUDINESS ACROSS SOUTHWEST CALIFORNIA TODAY. THE OFFSHORE FLOW HAS ENDED AND DENSE FOG IS PRESENT ALONG THE COAST. THE MARINE LAYER IS EXPECTED TO DEEPEN RAPIDLY TONIGHT AND WEDNESDAY. A WEAK UPPER LEVEL TROUGH MOVING ACROSS THE AREA MAY CAUSE SPRINKLES OR LIGHT RAIN LATE TONIGHT AND WEDNESDAY. MODERATE SOUTHERLY FLOW IS BEING OBSERVED IN THE LOWER LAYERS WITH STRONG SOUTHERLY FLOW ABOVE 10000 FEET BY BOTH WSR-88D VAD WINDS AND ACARS. SURFACE PRESSURE GRADIENTS ARE REVERSING AND FORECAST TO INCREASE TO +5 MB KSAN-KIPL BY 09/00Z. MODEL CROSS SECTIONS AND TIME SERIES SHOW A CLASSIC WARM FRONTAL PATTERN WITH STEADY LOWERING OF THE BASE OF THE SUBTROPICAL CLOUD SHIELD TODAY. THEN DUE TO INCREASED ONSHORE PRESSURE GRADIENTS SIGNIFICANT COOLING AND MOISTENING IN THE LOWER LAYERS TONIGHT THROUGH WEDNESDAY. WEAKENED AND ELONGATED UPPER LEVEL TROUGH MOVES ACROSS WEDNESDAY GENERATING -3 UBAR UPWARD VERTICAL MOTION PER AVN MODEL...POSSIBLY ENOUGH TO GENERATE PRECIPITATION. THE ETA/MESOETA MODELS ARE MORE AGGRESSIVE ON THE MOISTENING OF THE AIR MASS AND THREAT OF PRECIPITATION. CURRENT FORECASTS PRECIPITATION INTENSITY AND POPS WERE MORE IN LINE WITH AVN SOLUTION. GIVEN AVN INITIALIZATION WAS MUCH BETTER TONIGHT AND APPEARS TO BE VERIFYING WELL IN VIEW ON RECENT SATELLITE IMAGERY AND HOURLY RUC MODEL UPDATES...ONLY PERFORMED MINOR ADJUSTMENTS TO CUT BACK ON COVERAGE AND ONSET. AS FAR AS EXTENDED....SYSTEM ON THURSDAY MORE LIKELY TO PASS TO THE NORTH WITH MAIN EFFECT CONTINUING ONSHORE FLOW WITH GUSTY MOUNTAIN AND DESERT WINDS. MODEL GUIDANCE DID HAVE POPS FOR THIS DAY...ALREADY IN FORECAST SO LEFT IN BUT CONFIDENCE LOW. THE SYSTEM FORECAST BY MRF TO MOVE ACROSS THE STATE ON SATURDAY IS MORE LIKELY TO PRODUCE THE NEXT PRECIPITATION THREAT FOR SW CALIFORNIA. SAN 011 .SAN...DENSE FOG ADVISORY UNTIL 8 AM...CAZ043...SEE LAXNPWSAN. BALFOUR ca EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1005 AM EST TUE FEB 8 2000 TEMPS HAVE BEEN SLOW TO RISE SO FAR WITH EXTENSIVE CLOUD COVER OVER MANY AREAS THIS MORNING. HOWEVER...SOME BREAKS NOTED WITH NEARLY FULL SUNSHINE IN A FEW LOCATIONS NRN CWA. MORNING SOUNDINGS STILL FAIRLY DRY WITH A STRONG CAP OVER NORTH/CENTRAL PENINSULA...WHILE HIGHER PWATS AND A LITTLE MORE UNSTABLE WELL TO THE SOUTH. RADAR INDICATING ONLY A FEW LIGHT SHOWERS AND NO LIGHTNING PLOTTED OVER SE STATES. LATEST RUC INDICATING VORT MAX WILL MOVE OVER NRN PENINSULA THIS AFTERNOON THEN SHORTWAVE/STRONGER VORT DIGGING INTO GULF THIS MORNING WILL REACH ACROSS PENINSULA TONIGHT. CWA WILL BE IN RR JET QUAD THIS AFTN/EARLY EVE THEN AXIS OF JET WILL SHIFT S. WEAK INVERTED TROF NEAR E COAST FROM ABOUT THE CAPE SWD AND EXTENSIVE CLOUD COVER LIMITING HEATING...THIS SHOULD HELP INHIBIT THUNDER CHANCES THIS AFTERNOON. WILL EVALUATE 12Z RUN AND WATCH TRENDS BEFORE DECIDING ON THUNDER PROSPECTS SRN CWA FOR TONIGHT. PLAN TO UPDATE ZONES AND MAKE SOME ADJUSTMENTS FOR THIS AFTERNOON BASED ON TRENDS. MARINE...WINDS MAINLY WNW AND LESS THAN 10 KNOTS OVER WATERS THIS MORNING. SHOULD HAVE A GRADUAL INCREASE IN WINDS ON WED WITH SFC LOW DEVELOPMENT OFFSHORE. NO HIGHLIGHTS. .MLB...NONE. GLITTO fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 945 AM EST TUE FEB 8 2000 CURRENTLY...SFC ANALYSIS SHOWS LIGHT NW-N FLOW OVER THE AREA WITH A WEAK TROUGH LOCATED OFF THE FL E COAST. AN ILL-DEFINED LOW IS ESTIMATED 60-90 NM E OR ESE OF SGJ. SATELLITE IMAGERY SHOWS MID AND HIGH LEVEL CLOUDS OVER THE CWA AHEAD OF SHORTWAVE TROUGH LOCATED OVER THE NRN CENTRAL GULF OF MEXICO. RUC MODEL MOVES THIS FEATURE EWD THROUGH THIS AFTN AND SHOULD HELP ENHANCE PRECIP OVER THE WRN ATLC ALONG SFC TROUGH. AT THIS TIME...THINK SHOWERS WILL STAY OFF THE COAST BUT WILL MONITOR RADAR TRENDS. MAY MODIFY SKY COVER IN ZONES...MAINLY NRN PARTS. MARINE...WINDS ESTIMATED 10 KNOTS OR LESS ACROSS ENTIRE AREA WITH SEAS AROUND 2 FT. NEARLY ALL MODELS HAVE SFC LOW/TROUGH DEVELOPING JUST OFFSHORE SO WINDS/SEAS NOT MUCH OF A PROBLEM EXCEPT PERHAPS N PORTION OF MARINE AREA. THEREFORE...WILL PROBABLY TRIM BACK AFTN FORECAST. GA...NONE. FL...NONE. ARS fl WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 905 AM MST TUE FEB 8 2000 A WEAK DISTURBANCE HAS MOVED THROUGH THE NORTHERN PORTION OF THE CWA THIS MORNING. LOCAL FREEZING RAIN HAS BEEN REPORTED IN THE KALISPELL AND LIBBY AREAS...AND POTENTIAL STILL EXISTS THROUGH LATE-MORNING. STRATUS AND FOG WILL BE PROBLEMATIC TODAY WITH TIMING OF BREAKOUT AND ITS INFLUENCE ON DAYTIME HIGH FORECASTS. CURRENT FORECAST HAS FOG/LOW CLOUDS THROUGH THE MORNING HOURS...BUT COULD LAST INTO THE AFTERNOON. WILL BE MONITORING SITUATION...WITH POTENTIAL UPDATES LATER THIS MORNING. OTHERWISE FORECAST IN GOOD SHAPE. NO NEW MODELS TO LOOK AT THIS MODELS...YET. ETA/RUC LATE PER ADMNFD MESSAGE. JOHNSON mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 220 PM CDT TUE FEB 8 2000 SHORT TERM FORECAST PROBLEM IS HOW MUCH WEAK COOLING...LESSENED WIND AND INCREASING AFTERNOON CLOUD COVER WILL CUT TEMPS FROM TUE TO WED. NEXT PROBLEM IS CHANCE OF PRECIP BY LATE THURSDAY...WHICH LEADS INTO PROBLEM OF THURSDAY NIGHT THE ONLY SHORT TERM CONCERN IS THE AREA OF SHALLOW LOW CLOUDS AND FOG IN SRN IA WHICH HAS BEEN EXPANDING NW TOWARD OUR SOUTHWEST IOWA CWA ON THE LOW CLOUD ENHANCEMENT. THE MODELS DO NOT HANDLE THIS FEATURE...ALTHOUGH THE SFC RUC RH HINTS AT IT...AND BEGINS TO ADVECT IT BACK EAST AS EARLY AS 12Z. WILL KEEP AN EYE ON IT UP UNTIL ZONE TIME. THE MODELS ARE FAIRLY WELL IN AGREEMENT. ALL HAVE A SIMILAR SERIES OF WAVES IN BOTH THE NORTHERN AND SOUTHERN STREAM...WITH THE SOUTHERN BEING THE MOST SIGNIFICANT TO US. ALL HAVE ADJUSTED THE SHORT WAVE WHICH WILL SUPPORT THE PRECIP AFTER 60 HOURS SLIGHTLY SOUTH...AND PERHAPS SLOWED IT A LITTLE. THE RESULTING SURFACE PATTERNS ARE PATTERN IS ALSO SHIFTED A LITTLE SOUTH...BUT VERY SIMILAR ON ALL. THE AVIATION DOES NOT SEEM TO MAKE ANY STRONG ADJUSTMENTS TO THE OLD 84 HOUR MRF. ALTHOUGH THE RUNS ARE COOLER...THERE IS STILL A FAIR ARGUMENT THAT PRECIP IN THE SOUTHERN TWO THIRDS OF THE CWA THU EVE WOULD BEGIN AS LIQUID OR MIXED...ANY STRONG VERTICAL VELOCITIES WOULD LIKELY CLOSE THE SOUNDINGS AND FORCE THINGS OVER TO SNOW. FOR TOMORROW WILL HOLD TEMPS TO NEAR GUIDANCE. NORTHERN CWA IS LIKELY TO DEVELOP STRATUS AND COLD ADVECTION PUSHES IN WED NIGHT AND THIS AND INCREASING MID AND HIGH CLOUDS WILL HOLD UP LOWS. THURSDAY SHOULD BE CLOUDY AND MOS MAY BE LOW BUT FAN IS HIGH. .OMA...NONE POWERS ne EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WASHINGTON 830 AM PST TUE FEB 8 2000 HAVE ALREADY UPDATED ZONES TO BUMP UP POPS AND ADD FOG TO SEVERAL ZONES. 12Z KOTX SOUNDING WAS MOIST ALMOST ALL THE WAY UP. A SHALLOW LAYER OF DRY AIR AROUND 850 MB HAS ALMOST SURELY SINCE SATURATED. PRECIPITABLE WATER VALUES ARE WELL OVER 0.5 INCHES. 09Z RUC AND 12Z ETA BOTH AGREE IN INCREASING PRECIP ACROSS THE AREA TODAY... ESPECIALLY FROM I-90 NORTHWARD. MOIST SOUTHWEST 850 MB FLOW WILL ALSO INCREASE TO 25 KTS...ADVECTING IN MORE MOISTURE AND WARM AIR. CLOUDS AND RAIN SHOULD KEEP SURFACE TEMPS DOWN...BUT THE 12Z SOUNDING SHOWED THAT LITTLE BOUNDARY LAYER MIXING WOULD BE NEEDED TO CAUSE PRESENT HIGH TEMPS TO BE 5 DEGREES TOO COOL. TEMPERATURE AT SANDPOINT HAS QUICKLY RISEN TO 35F...ENDING ANY CHANCE FOR FREEZING RAIN THERE THIS MORNING. MULLAN PASS NOW REPORTING 33F...SO SNOW LEVELS MAY NOW BE CLOSER TO 5000-6000 FEET. BOTTOM LINE...LOOKS LIKE A WET AND SOUPY DAY. AWH/TC ...THE INFORMATION IN THIS PRODUCT CONCERNING WARNINGS AND FORECASTS IS VALID ONLY AT THE TIME OF ISSUANCE. THE LATEST WARNING AND FORECAST INFORMATION WILL BE FOUND IN THE APPROPRIATE PRODUCTS... GEG 042/030/039 882 CQV 043/029/040 982 S86 040/030/041 882 COE 044/029/040 881 WWP 040/029/038 883 LWS 050/038/048 462 MOS 045/031/041 EAT 040/031/042 640 .GEG...NONE. wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 240 AM CST WED FEB 9 2000 TOUGH FORECAST WITH ALL ELEMENTS IN QUESTION. ALSO A LOW CONFIDENCE FORECAST...ESPECIALLY PAST 24 OR 36 HOURS. IN THE SHORT TERM...ARCTIC FRONT OVER NRN PLAINS AND UPR MISS VALLEY SHOWING 3+ MB/3 HOUR HEIGHT RISES OVER DAKOTAS AND MN. THIS TO BECOME A MAJOR PLAYER IN OUR WEATHER IN THE 1ST AND 2ND PERIODS. MEANWHILE WARM FRONT HAS PUSHED EAST THRU CWA WITH SFC TROF FROM NC IA TO WRN KS. WEAK SFC LOW DEVELOPMENT NOW NOTED OVER S/W KS. WOULD EXPECT THIS LOW TO DEEPEN...THOUGH NOT MOVE MUCH OVER NEXT 18 HOURS AS UPR LO NR VEGAS SLIDES ENE THRU INTERMTN WEST AND INTO CEN/SRN ROCKIES. ETA/AVN HAVEN'T INITIALIZED THIS WELL...AND ESPECIALLY THE LOW STILL IN THE ERN PAC...PER NATIONAL DISC. 80H ANALYSIS FROM 00Z SHOWED A NICE ARCTIC AIRMASS POISED ALONG US/CAN BORDER. WOULD EXPECT THIS TO PUSH SOUTH TODAY BEHIND AFORMENTIONED FRONT. MVFR CIGS UP THERE NOW SHOULD EXPAND THRU DAY...BUT EVEN FASTER THIS EVENING. WITH VEGAS UPR SYSTEM EJECTING LATER TODAY AND THIS EVENING...WOULD EXPECT SW KS LOW TO REMAIN IN PLACE...AND DEEPEN LATER. THIS SHOULD CONTINUE TO PUSH WARM AIR INTO MO AND SRN IA...THENCE OVER COLD...SHALLOW DOME OF ARCTIC AIR WHICH ALWAYS WINS OUT. SO FOR TODAY...WIDE RANGE OF TEMPS ACROSS CWA WITH NEARLY STEADY TEMPS NORTH IN MID/UP 30S THEN FALLING. WITH SHALLOWNESS OF ARCTIC AIRMASS...MAY END UP MIXING A BIT THIS PM AND THUS SEEING CLOUDS. SPEAKING OF WHICH...THEY SHOULD BE CROSSING MN/IA BORDER AROUND 13Z. FARTHER SOUTH...GUIDENCE TEMPS BEGIN TO LOOK BETTER WITH ARND 5 DEG DIFFERENCE IN FWC VS FAN GUID SHOWING UP. WILL SIDE TOWARD COOL GUID AS LATEST RUC AND 00Z ETA PROG FRONT INTO CEN IA 18Z AND TO NEAR MO BORDER BY 00Z. THAT SAID...IF WARM ADVECTION CAN GET PUMPING GOOD ENOUGH...POTENTIAL EXISTS FOR BIG TEMP BUSTS...TOO COOL...IN SRN HALF OF CWA. TONIGHT...ARCTIC AIRMASS CONTINUES TO SLIDE SOUTH AND DEEPEN SOME. PER PROGGED SOUNDINGS...SATURATION OCCURS IN MID AND UPR LEVELS BY 06Z AS UPR LEVL DIV ENTERS AREA IN LEFT EXIT REGION OF SRN STREAM JET. MEANWHILE...WITH LOWEST LAYER NEARLY SATURATED AND 900-600 MB LEVEL DRY...MAY SEE SOME SEEDING GOING ON...HENCE DRIZZLE SOUTH BCMG FZDZ AND JUST FZDZ UP NORTH. ONLY A LITTLE MODEL OMEGA AND Q-G FORCING NOTED IN THE 03Z-12Z TIME FRAME. 285K ISENT SFC DEPICTING COND PRES DEFS GOING BELOW 20-30 MB ACROSS CWA. THUS SHOULD HAVE NO TROUBLE GETTING DRIZZLE GOING. PROGGED GUID TEMPS TOO HIGH IN ARCTIC AIRMASS AND WILL UNDERCUT INTO MID 20S ANYWAY...PER CURRENTS IN ND/NRN MN. THURS...SOME DRYING PER DOWNGLIDE ON ISENT SURFACES. SEEM TO BE SOMEWHAT BETWEEN SYSTEMS...THOUGH CERTAINLY SOME UNCERTAINTY WITH CURRENT NW WASH STATE VORT MAXES PROGGED TO COME THROUGH LATE THURS INTO THURS NIGHT. CURRENTLY HAVE A MENTION OF LIGHT SNOW AND WILL CONTINUE THIS THINKING WITH 30 POPS THURS NIGHT AND A MENTION OF FLURRIES THURS. MAY SEE SE CWA START OUT THURS MORNING AS LINGERING FZDZ BEFORE DEEPER COLD AIR COMES IN...CHANGING OVER TO MORE FLURRIES. FRI STILL LOOKING GOOD FOR A STRONG SYSTEM SOMEWHERE OVER THE PLAINS INTO MID MISS VALLEY. AVN CONTINUES TO POINT TO MAINLY S OF MY CWA. CURRENTLY HAVE LIKELY SOUTH AND 50 POP NORTH. THAT STILL LOOKS GOOD. THX TO ARX FOR COORD. .DSM...NONE. SEARCY ia AREA FORECAST DISCUSSION...CORRECTED TIME NATIONAL WEATHER SERVICE NORTH PLATTE NE 206 AM CST WED FEB 9 2000 ...POPS AND TEMPS FOR THU IS MAIN CHALLENGE... COMPARING SATELLITE DATA TO 06Z ETA FORECAST...ETA HAS A PRETTY GOOD HANDLE ON THE POSITION OF SYSTEMS. HOWEVER THE SHORTWAVE OVER THE SOUTHERN TIP OF NEVADA SEEMS TO BE UNDERDONE BY THE ETA. THE 00Z ETA IS IN PRETTY GOOD AGREEMENT WITH THE NEW RUC OUTPUT THROUGH 18Z. WITH NO OTHER GRAPHIC MODEL OUTPUT...WILL HAVE TO LEAN HEAVILY ON THE ETA. LOOKS LIKE ANOTHER TRANQUIL DAY FOR THE CWA WITH HIGH LEVEL CLOUDS THE ONLY CONCERN. WINDS WILL BE RATHER LIGHT FROM THE NORTH TO NORTHWEST IN MOST LOCATIONS WITH THE TROF SITTING OVER THE AREA. 850MB TEMPS COOL ABOUT 5-6C ACROSS THE NORTH TODAY SO EXPECT AFTERNOON TEMPS TO REACH THE MID 50S. IN THE SOUTHWEST...850MB TEMPS ONLY COOL 1-2C BUT WITH INCREASING HIGH LEVEL CLOUDS AND WITHOUT THE WESTERLY DOWNSLOPE FLOW TEMPS WILL HAVE A DIFFICULT TIME REACHING HIGHER THAN AROUND 60. SKIES WILL BE MOSTLY CLOUDY TONIGHT. A GOOD SHORTWAVE MOVES INTO THE NORTHERN PORTION OF THE PANHANDLE LATE TONIGHT. THIS SHOULD PROVIDE GOOD LIFT IN THE NORTHWEST PORTION OF THE CWA BY 12Z. LOW LEVEL NORTHEAST UPSLOPE FLOW WILL ALSO ADD TO THE LIFT. EXPECT SNOW TO DEVELOP LATE BUT WILL KEEP POPS RELATIVELY LOW UNTIL THE TOMORROW PERIOD WHERE POPS WILL INCREASE TO 60 PERCENT. THE SHORTWAVE WILL MOVE ACROSS NORTHERN NE THURSDAY. THE BEST LIFT WILL REMAIN IN THE WEST WHERE UPSLOPE FLOW WILL ENHANCE SNOW CHANCES. WILL KEEP POPS NEAR NGM GUIDANCE NUMBERS WITH THE LOWEST POPS...20-30 PERCENT... WILL BE IN THE SOUTHEAST...WHILE KEEPING 60 POPS IN THE NORTHWEST WHERE SOME ACCUMULATIONS ARE LIKELY. COLD AIR WILL FILTER INTO THE CWA FROM THE NORTH ON THU. TEMPS IN THE NORTH WILL ONLY BE IN THE 30S THU...IN THE SOUTH EXPECT TEMPS TO REACH THE MID 40S BEFORE FALLING OFF INTO THE 30S BY LATE AFTERNOON. DO NOT EXPECT TO MAKE ANY CHANGES TO THE EXTENDED AT THIS TIME. .LBF...NONE DDB ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 123 AM EST WED FEB 9 2000 PRIMARILY A TEMPERATURE FORECAST THIS MORNING. SRN STREAM MINOR WAVE IS MAKING GOOD TIME ACROSS NRN FL THIS MORNING. 00Z H5 HAND ANALYSIS SHOWED GOOD RISE FALL COUPLET AT H5... AND BY 15Z THE RUC HAS THE H8 CIRCULATION WELL OFF SHORE. SO ABOUT ALL WE/LL HAVE IS A MID DECK TO THE DSNT E (I HOPE). ARL 500M BACKWARDS TRAJECTORY ON THE ETA HAS SOURCE REGION FOR TODAYS PARCEL OVER NRN GA. A SWITCH FROM YDAY...BUT W/H8 TEMPS ONLY RECOVERING TO AROUND +6...NEAR 60 IS ABOUT THE BEST WE WL DO IN NON-MTN LOCATIONS...WHICH IS RIGHT IN LINE W/THE ZONES. GOOD RADIATIONAL COOLING OVERNIGHT...AND WL STICK W/RAFS NUMBERS... SAVE CLT WHICH IS ITS USUAL 5 TO 6 DEG F TOO HIGH FOR MINS ON THESE TYPE OF NIGHTS. BY THU...H8 TEMPS RECOVER TO AROUND +9 DEG C. COUPLE THIS W/AN INCREASING SW FLOW...AND THE BULK OF ANYTHING BUT HIGH CLOUDS CONFINED TO THE W OF THE MTNS...AND HIGHS SHOULD SOAR INTO THE U60S TO NEAR 70. THIS IS A CORRECTION OF ONLY A COUPLE DEGREES OVER RAFS. W/A FAST ZONAL FLOW...MOST OF THE ACTION WL BE CONFINED TO ALONG AND N OF THE PATH OF SRN STREAM MINOR WAVES...MAINLY IN AREAS OF UPGLIDE OVER POLAR FRONT. THIS ACTION WL PRIMARILY BE NORTH OF US...AND WE WL HAVE A HARD TIME SEEING MUCH OF ANYTHING PCPN WISE THE REST OF THE WEEK. WL IGNORE NGMS 40 POPS FOR THE MTNS THU NGHT AND KEEP FRI DRY AS WELL. PRELIMINARY NUMBERS: AVL 56/29/63 000 CLT 59/34/68 000 GSP 59/36/68 000 .GSP...NONE. MCAVOY sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 330 AM CST WED FEB 9 2000 FCST CHALLENGES ARE TEMPS THRU PD AS ARCTIC FNT SAGS S ACRS CWA... AND PCPN TYPE/CHCS FOR TONIGHT AND THU. DATA DEPRIVED THIS MORN WITH NATIONAL AWIPS PROBLEMS. RUC...ETA AND UW-NMS ONLY MODELS TO LOOK AT. SFC OBS JUST NOW BEGINNING TO FLOW IN. ETA CONTS TO SHOW ARCTIC FNT...OVR NRN WI ATTM...SLIDING S OF CWA DURING DAY TODAY. FNT THEN BECOMES STRNY OVR NRN IL AS SRN PLAINS LOW IS EJECTED NE TNGT. COLDEST OF AIR LAGS FAR BHND FNT SO FEELING IS TEMPS WILL STILL MANAGE TO CLIMB A FEW MORE DEGREES INTO THE AFTN... BEFORE LEVELING OFF. IR/11U-3.9U LOOPS INDICATING ST SLIDING S OVR NRN WI BHND THE FNT AND CI MOVG IN FROM THE W. MOST AREAS SHLD SEE SOME SUNSHINE EARLY...WITH MID/HI CLDS GRADLY THICKENG AND ST ARRIVING DURING AFTN/EVE. NRN BRANCH OF SPLIT FLOW TNGT SPRDS IN PCPN. GOOD OVRRUNNING SITUATION SETTING UP IN BAROCLINIC ZONE ACRS WI. BUFKIT SNDGS HOLD ON TO WARM LAYER ALOFT SO MXD PCPN APPRS WAY TO GO. BEST DYNAMICS REMAINS N OF CWA. ISNT LIFT REMAINS WK ACRS CWA WITH 2-3 G/KG OF LIQUID AVAIL. ENOUGH VV/OVRRUNNING FOR CHC POPS ACRS CWA. WL CARRY LIKELY POPS IN FAR NRN PTNS. NO HEADLINES NOW...AS PCPN SHLD BE LGT...WL LET NEXT CREW TAKE FINAL LOOK. LOW TRACKS ACRS CNTRL IL EARLY THU...PULLING SRN STREAM GULF MOISTURE INTO SYS. MOST OF WI LOOKS SAFE FROM THIS SURGE OF MOISTURE AS IT SLIDES INTO THE CNTRL GRTLKS. AS SFC LOW PULLS INTO IN THU AFTN...AND ASSCD VORT SLIDES E...PCPN SHLD DIMINISH. STRG CAA IS DRAWN INTO REGION BHND SYS BY THU AFTN. TEMPS WL NOT MOV MUCH THU AND WL TRIM MOS TEMPS. CAA AND ABUNDANT LOW LVL MOISTURE COULD STILL PRODUCE A FEW -SHSN INTO AFTN. DELTA T/S OVR NRN LM TO ARND 14 WITH NNE FLOW MAY ALSO KICK IN A LITTLE LES. THANKS TO LOT FOR CORD. .UW-NMS SIMILAR TO ETA...A BIT SLOWER WITH COOLER AIR. .MKX...NONE. /.../.../...0 $$ JK wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1120 AM CST TUE FEB 8 2000 CURRENT FOG/STRATUS SATELLITE IMAGERY SHOWS SOME PERSISTENT LOW CLOUDS ACROSS NORTHEAST IA AND SOUTHWEST AND CENTRAL WI LATE THIS MORNING. THE LATEST MESO-ETA CONTINUES TO KEEP THE ATMOSPHERE SATURATED FROM 925MB ON DOWN THIS AFTERNOON...WITH THE LATEST RUC AND 12Z ETA ALSO SHOWING THIS SOMEWHAT. INVERSION HANGS IN PRETTY WELL...BUT THIS LOW CLOUD LAYER IS NOT THAT THICK. WOULD NORMALLY EXPECT MUCH OF THIS CLOUD LAYER TO DISSIPATE AS THE SUN "EATS AWAY"...BUT INCOMING HIGH CLOUDS COULD INHIBIT SOME OF THAT. EXPECT THE LOW DECK TO ERODE TO THE WEST AND NORTH...WHILE SOUTHERN CUTS WILL LIKELY BE STUCK UNDER THE CLOUDS FOR MUCH OF THE AFTERNOON. WILL ADJUST THE ZONES FOR THE CLOUD TRENDS...AND ALSO COOL TEMPS A BIT ON ACCOUNT OF THE CLOUD COVER. .LSE...NONE. RIECK wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 320 PM CST WED FEB 9 2000 SNOWFALL TONIGHT INTO THURSDAY IS THE MAIN CONCERN THIS FORECAST. KMVX/KDLH RADARS LIGHTING UP THIS AFTERNOON...AS A SHORTWAVE SLIDES SOUTHEAST OUT OF THE NORTHERN ROCKIES. THE SNOW WAS BEING GENERATED BY INCREASE H8 WAA...WITH A STRONG BAROCLINIC ZONE ACROSS MN/WI. THE SNOW WAS ALSO AIDED BY ISENTROPIC LIFT AND STRONG OMEGA...WHICH WAS LIKELY BEING INDUCED BY RRQ JET DYNAMICS. MODELS ARE FAIRLY CLOSE...BUT WILL GO WITH THE RUC FOR THE EVENING AND ETA FOR THE REMAINDER OF THE FORECAST. WILL MAINTAIN WORDING OF 2 TO 4 INCHES IN THE SOUTH WITH LESSER ACCUMULATIONS NEAR THE INTERNATIONAL BORDER. ALTHOUGH THE SNOWFLAKES IN THE AREAS CURRENTLY SNOWING ARE FAIRLY SMALL...700 MB TEMPS FALL INTO THE FAVORABLE RANGE FOR LARGER FLAKES DURING THE NIGHT. THIS SHOULD HELP TO JUSTIFY THE HIGHER AMOUNTS. MOISTURE FROM LAKE SUPERIOR SHOULD ALSO HELP TO CONTRIBUTE TO SOME HIGHER AMOUNTS. WILL MAINTAIN WORDING OF LOCALLY HIGHER AMOUNTS ADJACENT TO LAKE SUPERIOR. THE SOUTH SHORE COULD GET THE HIGHEST AMOUNTS...BUT FOR NOW WILL JUST SAY AROUND 4 INCHES...WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN THE HIGHER TERRAIN. RIDGING WILL POKE IN ON THURSDAY...BRINGING A CLEARING TREND TO THE AREA FROM NORTH TO SOUTH DURING THE DAY. 850 TEMPERATURES FALL FAIRLY GRADUALLY DURING THE DAY. LOOKS LIKE A COLD NIGHT THURSDAY NIGHT...WITH LIGHT WINDS AND COLD 850 TEMPS. MOST PLACES SHOULD SEE TEMPERATURES FALL WELL BELOW ZERO. COORD WITH FGF...MPX...THANKS. .DLH...NONE. DAP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 300 PM CST WED FEB 9 2000 MAIN QUESTION IS DISTRIBUTION OF SNOW TONIGHT. SNOW HAS MOVED INTO WEST CENTRAL MN WITH MID LEVEL ISENTROPIC LIFT AHEAD OF SHORT WAVE TROUGH...CURRENTLY PUSHING INTO NRN ROCKIES. SECOND SYSTEM HAS SPUN UP IN NRN NM/SRN CO...QUITE A BIT STRONGER THAN 12Z MODELS HAD INDICATED. FOR OUR FORECAST AREA RUC INDICATES SOME INSTABILITY OVER SW MN ASSOCIATED WITH THIS SYSTEM. FORECAST FOR SNOW TONIGHT WILL REFLECT MOISTURE AND BETTER FORCING ACROSS NRN PORTIONS. MAINLY LARGE SCALE INSTABILITY...SUPPORTED BY UPPER DIVERGENCE WITH RIGHT ENTRANCE OF THE JET...COULD MAKE FOR SOME ACCUMULATION ACROSS CENTRAL PORTIONS...EVEN WITH LESS MOISTURE. OVER THE SOUTH A MIXTURE LIKELY AT FIRST...BEFORE PRECIPITATION CHANGES TO ALL SNOW. MUCH COLDER AIR MOVES IN ON THURSDAY. WIND FORECAST HAS BE RAISED FROM GUIDANCE SOME DUE TO COLD ADVECTION AND INCREASING SURFACE PRESSURE. LOW TEMPERATURES FOR THURSDAY NIGHT HAVE BEEN LOWERED FROM GUIDANCE WITH EXPECTED SNOW COVER AND ARCTIC NATURE OF LOW LEVEL AIR. EXPECT NEXT SYSTEM TO SPREAD SOME CLOUDINESS TO SRN PORTIONS ON SATURDAY. SYSTEM FROM PACIFIC NW FORECAST BY MRF TO SPREAD MORE SNOW TO REGION SUNDAY MONDAY. .MSP...NONE. SCOTT mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1005 AM CST WED FEB 9 2000 FORECAST HAS BEEN UPDATED FOR WORDING. LATEST RUC MODEL INDICATES BEST QG FORCING/MOISTURE WILL DEVELOP IN EXTREME NRN PORTIONS OF FORECAST AREA THIS AFTERNOON. PRECIPITATION PROBABILITIES HAVE BEEN ADJUSTED FOR BEST POTENTIAL. TEMPERATURES GENERALLY WARMER THAN EARLIER FORECAST. WITH WAVE AHEAD OF PACIFIC NW SHORT WAVE TROUGH...HIGH TEMPERATURES HAVE BEEN RAISED IN ALL EXCEPT FAR NORTHWEST PORTION OF AREA...WHERE CLOUDS AND PRECIPITATION WILL KEEP HIGHS DOWN. .MSP...NONE. SCOTT mn EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WASHINGTON 900 AM PST WED FEB 9 2000 12Z KOTX SOUNDING SHOWS A MOIST LAYER OF AIR NEAR THE GROUND THAT EXTENDS ONLY UP TO 890 MB WITH DRY AIR LOCATED ABOVE THAT. DESPITE A STABLE SUBSIDENT LAYER FROM 890-825 MB...DAYTIME HEATING SHOULD PROVIDE ENOUGH MIXING TO CLEAR OUT THE STRATUS/FOG. 12Z RUC AND 12Z ETA FORECAST SOUNDINGS AGREE IN DEPICTING STEEPENING LOW LEVEL LAPSE RATES THIS AFTERNOON. EVEN WITH ONLY A SHALLOW LAYER OF MOISTURE...MOUNTAIN SNOW SHOWERS CAN NOT BE RULED OUT...BUT WEAKENING WIND FIELDS SHOULD KEEP ANY SHOWERS STRICTLY CONFINED TO THE MOUNTAINS. WILL UPDATE FORECAST AROUND 10 AM MAINLY TO ACCOUNT FOR TEMPORAL WORDING. AWH/JL ...THE INFORMATION IN THIS PRODUCT CONCERNING WARNINGS AND FORECASTS IS VALID ONLY AT THE TIME OF ISSUANCE. THE LATEST WARNING AND FORECAST INFORMATION WILL BE FOUND IN THE APPROPRIATE PRODUCTS... GEG 040/031/038 111 CQV 042/028/039 222 S86 042/027/038 222 COE 043/032/039 111 WWP 039/026/039 222 LWS 052/035/049 011 MOS 044/033/040 EAT 038/029/038 000 .GEG...NONE. wa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 300 PM CST WED FEB 9 2000 FCST CHALLENGE IS TYPE OF PCPN AND HOW MUCH LATE TONIGHT INTO THU MRNG. CURRENT SATELLITE PIXS SHOW A VERY ROBUST VORTMAX IN SERN CO MOVG NEWD. I AGREE WITH SURROUNDING OFFICES IN THAT MODELS DON/T DO JUSTICE WITH THIS VORTMAX BY WEAKENING IT WITH TIME. WE FEEL THIS SYSTEM/S MOISTURE/DYNAMICS WILL BE MORE PRONOUNCED AND MERGE WITH HIGHER RH/S AND PCPN OF NRN BAROCLINIC ZONE ACRS MN INTO NRN WI. THEREFORE WILL GO LIKELY WITH PCPN LATE TNT INTO THU MRNG ACRS SRN WI. AVN MODEL THUS IS BEST AT SHOWING BROADER AREA OF PCPN/QPF EXTENDING FURTHER SOUTH FROM THE MAIN WEST TO EAST BAND ACRS MN INTO NRN WI...AND AVN MODEL HAS BETTER MERGING. AS FOR WETZEL INGREDIENTS APPROACH...ETA MODEL HAS LGT TO MODERATE QG FORCING ACRS SRN WI LATE TNT/ERLY THU MRNG FROM 800 TO 700MB... AND EVEN UP TO 600 MB ARND 12Z THU. RH/S ARE 80 TO 90PCT AND TEMPS MINUS 12 TO MINUS 14 AT 600MB. SO WE SHD HAVE ICE CRYSTALS INTRODUCED INTO PCPN PROCESS. COUPLE THIS WITH SOME INSTABILITY BETWEEN 06Z AND 12Z ONE HAS THE POSSIBILITY OF CONVECTION..PROBABLY SLANTWISE. THUS THERE COULD BE SOME SNOW/SLEET SHWERS EMBEDDED IN AREAS OF FRZG RAIN OR FRZG DRZL. HAVE TO GO MIXTURE IN FCST. OTHERWISE FCST SOUNDINGS INDICATE FRZG RAIN CHANCES FOR MSN-MKE SOUTH DUE TO TEMPS OF PLUS 1 TO 3 IN INVERSION LAYER..AND BELOW FRZG NEAR SURFACE. ALL SAID AND DONE... WILL GO WINTER WEATHER ADVISORY LATE TNT AND THU MORNING. PCPN WILL BE ALL SNOW FROM MQT COUNTY EWD TO SHEBOYGAN COUNTY WHERE FCST SOUNDINGS ARE ZERO OR OR BELOW. WILL GO WITH ACCUMS AROUND AN INCH FOR THIS AREA. AFTER LOW PULLS AWAY FROM WRN GRT LKS RGN THU AFTN WE LOSE ISENTROPIC LIFT WITH LOW LVL FLOW BECOMING MORE NW TO N. MODELS SHOW COLDER AIR COMING IN BUT WITH TEMP DIFFERENCES BETWEEN LAKE MICHIGAN WATERS AND 850MB IN THE MINUS 12 TO MINUS 16 RANGE...ENUF FOR LAKE EFFECT SNOW NRN LAKE MICHIGAN... BUT NOT ENUF FOR SRN LAKE MICHIGAN. SO WILL ONLY GO WITH FLURRIES THU AFTN. CHANCE FOR LGT SNOW BY FRI AFTN AS NEXT SYSTEM ARRIVES...AND INTO WEEKEND. THANKS TO GRB ARX LOT FOR CORD. .UW-NMS MORE SIMILAR TO NGM AND RUC FOR PCPN QPF...WITH TIMING THE SAME WITH ALL MODELS. .MKX...WINTER WEATHER ADVISORY LATE TNT AND THU MRNG WIZ056>060- /.../...0...0 $$ KAPELA wi