AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES, IA 905 PM CST MON FEB 14 2000 WILL UPDATE THE FORECAST TO TAKE OUT ANY SNOW XCPT FOR FAR N. SUM ADJSTMNTS ON TEMPS DESPITE WAA. LOOK AT TGNTS UA SHOW DRY MID LYRS WITH LTL CHC FOR ANY SEEDING OF NON EXISTENT LO CLDS. RADARS UPSTREAM PPINE. BETTER WAA ALTL FARTHER W AND N IF LTST RUCS TRENDS HOLD. "BEST" MOISTURE CONVERGENCE N OF ST. .DSM...NONE FORSTER ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 945 PM EST MON FEB 14 2000 LATEST IR LOOP SHOWS SOME LAKE EFFECT CLOUDS HAVE DEVELOPED ALONG THE LAKESHORE AND ARE MOVG E. MARGINAL LAKE INSTABILITY IS PLAYING A ROLE IN THE SC DEVELOPMENT AND WILL CONTINUE TO DO SO FOR A FEW MORE HOURS SO SAYS THE RUC...UNTIL WAA DEVELOPS. A FEW FLURRIES ARE ALSO BEING REPORTED WITH MKG DOWN TO 7SM -SN. FARTHER WEST SC IN ERN WI WAS MOVG EAST INTO LAKE MI. MID/HIGH CLOUDS WERE NOTED WEST OF A DLH-STL LINE. ALL OF THESE CLOUDS WILL CROSS INTO THE CWA AFTER MIDNIGHT. WITH THE SC PROGRESSING EAST AT A PRETTY GOOD CLIP WILL JUST GO MO CLOUDY OVERNIGHT. GOING TEMP FCST LOOKS PRETTY GOOD. .GRR...WINTER STORM WATCH MASON...LAKE...OSCEOLA...CLARE COUNTIES TUESDAY AND TUESDAY EVENING FOR THE POTENTIAL OF SIX OR MORE INCHES OF SNOW. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 330 PM EST MON FEB 14 2000 MAIN FORECAST CHALLENGE THIS PERIOD WILL PRECIPITATION TYPES FOR TUESDAY NIGHT. TONIGHT...CLOUDS AND TEMPERATURES TO BE A PROBLEM. SKIES HAVE CLEARED ACROSS NORTHWEST PORTION OF CWA. RUC LOW LEVEL RH FIELD SHOWS CLEARING TO BE SLOW THROUGH REMAINDER OF CWA THROUGH EARLY EVENING. ACROSS WI AND MN...CLOUDS AND SCATTERED FLURRIES EVIDENT ASSOCIATED WITH VORT LOBE TO CROSS CWA BETWEEN 00 AND 06Z. THIS LIKELY TO LEAD TO INCREASE IN CLOUDS WHERE CLEAR...AND KEEP CLOUDS IN ELSEWHERE. MAY EVEN SEE A FLURRY OUT OF THESE CLOUDS. AFTER 06Z... EXPECT SOME DEGREE OF CLEARING. AS WINDS SWING AROUND TO WEST AND SOUTHWEST MAY SEE SOME LAKE CLOUDS ADVECT IN TO CWA...ALTHOUGH 850 MB TEMPS WILL BE WARMING AFTER 06Z SO NOT TOO CONCERNED WITH SIGNIFICANT LAKE CLOUDS. WITH SNOW COVER IN EXCESS OF A FOOT ACROSS NORTHERN HALF OF CWA...AND SIX INCHES OF THAT NEW...EXPECT THAT ANY DEGREE OF CLEARING WILL LEAD TO A RAPID TEMPERATURES DECLINE THERE. ACROSS THE SOUTH...ALSO LIKELY TO SEE TEMPERATURES DROP QUICKLY IF CLEARING OCCURS. WITH UNCERTAINTY ON TEMPS...WILL USE WIDE 10 DEGREE RANGE. TUESDAY...LOW TRACKS FROM HIGH PLAINS TO WI BY AFTERNOON. STRONG ISENTROPIC LIFT...PRODUCING 6 TO 8 MICROBAR/SEC UVVS...AHEAD OF THE LOW AND IMPRESSIVE THETA-E ADVECTION WILL ALLOW SNOW TO BREAK OUT ACROSS NORTHERN TWO THIRDS OF THE CWA BY LATE AFTERNOON...WITH CHANCE PROBABILITIES FOR SOUTHERN ONE THIRD. LOW TRACKS ACROSS NORTHERN LOWER MI ON TUESDAY NIGHT...OFFERING MESSY PRECIP TYPES. EXPECT BULK OF THE PRECIP TO FALL BETWEEN 21Z /BEGINNING EARLIEST NORTH/ AND 06Z. ETA AND NGM MODELS INDICATE THAT PRECIP ACROSS MIDLAND...BAY...AND HURON COUNTIES TO REMAIN ALL SNOW. QPFS FOR EVENT ARE ABOUT 0.2 INCH HERE...BUT WITH STRONG ISENTROPIC LIFT AND IMPRESSIVE THETA-E ADVECTION COULD FEEL THAT 3 TO 6 INCH TOTAL AMOUNTS HERE NOT OUT OF THE QUESTION. WITH SNOW TO START DURING THE AFTERNOON ACROSS THIS TIER...WILL HAVE CATEGORICAL POPS AND ACCUMULATIONS OF 1 TO 2 INCHES BY LATE AFTERNOON. NEXT TIER DOWN...SANILAC...TUSCOLA...SAGINAW...LIKELY TO SEE MAINLY SNOW...WITH SOME PL/FZRA MIXING IN AT TIMES. MIXED PRECIP WILL HOLD ACCUMULATIONS DOWN HERE TO AROUND 2 TO 4 INCHES. CENTRAL TIER TO INCLUDE FNT AND PTK WILL SEE CHANCE SNOW FOR TUESDAY AFTERNOON...WITH CATEGORICAL POPS TUESDAY NIGHT. PRECIP WILL START AS SNOW...BUT SHOULD TRANSITION THROUGH TO MIX. MELTING LAYER LOOKS TO BE SUFFICIENTLY DEEP TO PRODUCE FREEZING RAIN OR RAIN. ETA 2M TEMPS ARGUE FOR MOSTLY FZRA. FWC TEMPS/TDS ALSO SUGGEST FZRA WITH TDS REMAINING IN 20S THROUGH EVENT. WITH STRONG LOW LEVEL WAA ONGOING...MAY BE SUFFICIENT TO BOOST TEMPERATURES ABOVE FREEZING SO WILL INCLUDE MENTION OF RAIN. FOR NORTHERNMOST ZONE...SNOW ADVISORY COULD BE NECESSARY...WITH WINTER WEATHER ADVISORY POSSIBLE NEXT TWO ZONES. WILL WAIT FOR LATER RUNS TO ADDRESS. FINALLY FOR SOUTHERN TWO TIERS OF COUNTIES INCLUDING DTW...ARB...AND ADG...WILL CARRY A 30 PERCENT CHANCE OF SNOW FOR LATE TUESDAY...THEN TRANSITION THROUGH TO A MIX AND FINALLY RAIN. ETA AND FWC TEMPS/TDS SHOW SAME SCENARIO AS FOR FNT/PTK COUNTIES...BUT BELIEVE STRONG LOW LEVEL WAA WILL BE SUFFICIENT TO PUMP ENOUGH WARM AIR INTO CWA TO WARM ABOVE FREEZING AT SURFACE. AFTER 06Z...EXPECT PRECIP TO TAPER TO DZ/FZDZ. ON WEDNESDAY...LOW PULLS OUT WITH CYCLONIC FLOW TO KEEP CLOUDS AND CHANCE OF SHSN/SHRA IN PLACE FOR MORNING. BY AFTERNOON...MAY SOME CLEARING...BUT FOR NOW WILL KEEP SKIES MOSTLY CLOUDY. TEMPERATURES LIKELY TO HOLD STEADY IN FWC/FAN RANGE. AND THE EXTENDED... MRF...UKMO...AND CANADIAN IN GOOD AGREEMENT IN SPINNING UP LOW OVER SOUTHERN PLAINS LATE THURSDAY AND TRACKING LOW TO THE NORTHEAST REACHING LOWER MICHIGAN FRIDAY/FRIDAY NIGHT WITH CANADIAN FASTER BY ABOUT 12 HOURS. ON THE OTHER HAND...ETA-XX SHOOTS A WEAK LOW EMBEDDED IN NORTHERN STREAM TOWARD CWA AT ABOUT THE SAME TIME. WITH FLOW QUASI-ZONAL TIMING DIFFERENCES OF THIS MAGNITUDE NOT UNEXPECTED. RUN-TO-RUN CONTINUITY ON MRF NOT INSPIRING MUCH CONFIDENCE AS 14/00Z RUN/S 120HR SOLUTION...19/00Z...SIMILAR TO 2-DAY OLD SOLUTION...WITH PREVIOUS RUN DEPICTING DEPARTING HIGH FOR CWA. BOTH CANADIAN AND MRF WOULD SUPPORT A NEARLY ALL RAIN EVENT...WITH CANADIAN/MRF QPFS AROUND ONE HALF INCH. ON THE OTHER HAND...ETA-XX BRINGS PRECIP IN AS ALL SNOW...WITH ONE QUARTER INCH QPF. GIVEN UNCERTAINTY IN TIME AND TYPE WILL GO WITH CHANCE OF RAIN OR SNOW. MEANWHILE...MORE UNCERTAINTY LATER IN THE PERIOD AS MRF TAKES MAJOR DEPARTURE FROM ZONAL FLOW TO DROP A CLOSED LOW OVER THE LAKES ON SUNDAY BEFORE RIDGING BUILDS BACK IN ON MONDAY. NEITHER CANADIAN NOR ETA-XX SUPPORT THIS. FOR NOW WILL KEEP SUNDAY AND MONDAY DRY. .DTX...NONE. OKEEFE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1130 AM EST MON FEB 14 2000 MAIN FCST CONCERNS THIS AFTN ARE CLOUD TRENDS AND SNOW CHANCES. 16Z SFC CHART SHOWING ALL OF UPR MI UNDER INFLUENCE OF HIGH PRESSURE RIDGE STRETCHING FM JAMES BAY DOWN INTO THE CENTRAL PLAINS STATES. HOWEVER...WX IS NOT COMPLETELY CALM THIS MORNING AS MANY AREAS OF CLOUDS ARE MAKING AN IMPACT ON THINGS AND COUPLED SHRTWVS CURRENTLY OVR NRN MN AND S CNTRAL MN PRODUCING LGT SN OVR THE GOPHER STATE. ATTM BELEIVE UPR MI WL MISS MOST OF SIG LGT SN TODAY AS SHRTWVS APPEAR TO BE SPLITTING THE YOOP WITH NRN ONE EXITING TO EAST ACROSS SRN ONTARIO AND SRN ONE CONTINUES TO DIG SOUTHEAST TOWARD SRN WI. BOTH MESOETA AND RUC INITIALIZED THE NRN SHRTWV FAIRLY WELL...HOWEVER ONLY THE RUC HAS HAD ANY SUCCESS WITH SECONDARY SHRTWV AND EVEN SO APPEARED TO WEAK WITH IT FM THE BEGINNING. SFC METARS ALSO PAINT A PICTURE OF SPLIT PRECIP AREAS AS NORTH OF A BJI TO DLH 50W CORRIDOR 3-5SM W/ -SN IS A COMMON THEME AND SOUTH OF THE CORRIDOR THE SAME CONDITIONS ARE PRESENT. KDLH 88D ALSO SHOWING AN AREA OF < 20DBZ RETURNS ACROSS NERN MN ATTM. RESULT IS TO PUT A BRIEF PERIOD OF SN OR FLURRIES ACROSS ONT AND THE KEWEENAW WITH EVERYBODY ELSE ACROSS THE NRN FA SEEING FLURRIES AT BEST. WITH INTERPOLATION OF THE SRN SHRTWV AND METARS...LOOKS LIKE BEST FORCING WON'T AFFECT SRN UPR MI FOR THE REST OF THE AFTERNOON. MOSTLY CLOUDY SKIES WL BE THE RULE FOR WRN FA AS HIGH AND MID LEVEL CLOUDS INVADE IN ADVANCE OF COUPLING SHRTWVS...FOR THE ERN FA ONLY INCREASING HIGH CLOUDS LATE WL SPOIL MOSTLY SUNNY DAY. TEMPS IN WRN FA WERE BUMPED DOWN A FEW DEGREES DUE TO INCREASING CLOUDS...OTHERWISE TEMPS ELSEWHERE LOOK ON TRACK. .MQT...NONE. JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1053 AM EST MON FEB 14 2000 WEAK CYCLONIC FLOW CONTINUES ACROSS MOST OF LOWER MI ON THE BACKSIDE OF THE STRONG SFC LOW MOVING NE TOWARD NEW ENGLAND. WEAK RIDGING IS BUILDING INTO UPR MI AND WI AHEAD OF A VORT LOBE OVER THE ARROWHEAD OF MN. CAA IS TAKING PLACE WITH VERY LITTLE SFC WARMING OCCURRING SO FAR THIS MORNING. WINDS HAVE BEGUN TO SHIFT TO THE N/NW AS THE LOW PULLS AWAY. LAKE HURON SNOW BANDS FEEDING OFF LOW LEVEL CYCLONIC FLOW AND RESIDUAL MOISTURE ARE TOO SHALLOW TO SHOW UP ON RADAR...BUT ARE STILL PERSISTING PER LATEST OSC AND MBS OBS. VSBYS HAVE BEGUN TO INCREASE AS BANDS BECOME LESS ORGANIZED WITH WINDS SHIFTING TO THE N. EXPECT THIS DIMINISHING TREND ACROSS NE LOWER MI TO CONTINUE DURING THE AFTERNOON WITH WINDS SHIFTING TO THE NW LATE. HOWEVER...WINDS SHIFTING TO THE NW WILL ALSO BRING LAKE EFFECT BANDS ACROSS LAKES SUPERIOR AND MI ONSHORE IN ERN UPR AND NW LOWER MI LATE IN THE DAY. INVERSION HEIGHTS STAY AROUND 4500 FT...WITH DELTA T'S OF 15 AND ENOUGH LOW LEVEL RH (APPROX. 50-60 PCT) TO MAINTAIN PRODUCTION OF SCT LAKE SHSN THRU THE AFTERNOON. EXPECT ENHANCING LIFT FROM THE VORT LOBE WILL NOT PLAY A BIG ROLE UNTIL EARLY EVENING BASED ON LATEST RUC POSITION AND TIMING, WHICH MATCHES WELL WITH COOLER CLOUD TOPS OVER THE ARROWHEAD AS SEEN ON IR SATELLITE LOOP. WILL WORD NE LOWER MI ZONES AS SCT SHSN TAPERING TO FLURRIES. FOR ERN UPR AND NW LOWER MI...WILL WORD AS A CHANCE OF SHSN LATE...WITH BEST CHANCES ACROSS CHIPPEWA COUNTY AND FAR NW LOWER MI ZONES. WILL ALSO HAVE TO ADJUST AFTERNOON HIGHS DOWNWARD A CATEGORY OR TWO BASED ON LATEST TRENDS AND SLIGHTLY STRONGER CAA THAN PREVIOUSLY ANTICIPATED. .APX...NONE. EME mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 935 PM EST SAT FEB 12 2000 COLD FRNT VIA MSAS ORIENTED ACROSS ILM CWA NE-SW. PROGGED AND EXTRAPOLATED TO MOVE OFF THE COAST AROUND MIDNIGHT. STILL HAVE ONE UPPER VORT TO PASS ACROSS THE AREA DURING THE EARLY MORNING HRS VIA MESO-ETA AND RUC. MOISTURE LIMITED AT THIS TIME AND DO NOT EXPECT ANY PCPN...ONLY FEW/SCT CLDS AT BEST. WILL GO WITH MSTLY CLEAR. TEMPS...CAA TO OCCUR OVRNITE. CURRENT PRESCRIBED TEMPS LOOK AOK. WILL SEE 10 AM UPSTREAM READINGS AND SEE IF TWEAKING IS NEEDED. CWF...CURRNTLY A LULL IN THE WND SPEEDS PRIOR TO CFP BUT SEAS UP THERE. WITH CONTINUED RELATIVELY STRONG PG AND CAA AFTR FRNTL PASSAGE...WILL CONTINUE SCA. .ILM...SMALL CRAFT ADVISORY AMZ250-252-254-256. RALF nc FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 820 PM CST MON FEB 14 2000 FCST CHALLENGE...IS PLACEMENT OF SNOW BAND AND TIMING SNOW DEVELOPMENT. WATER VAPOR SHOWS POTENT 50H SYSTEM MOVING INTO CENTRAL IDAHO. NOT PARTICULARLY IMPRESSED WITH 12Z MODELS AND THEIR PLACEMENT OF THE SYSTEM ATTM. DIFFICULT TO PIN DOWN WHICH ONE IS BEST ATTM. LATEST RUC WOULD SUPPORT MORE OF THE AVN WITH 85H LOW OVER SE MT AND DEVELOPING BAND OF 85H WAA OVER SRN SD THIS EVENING MOVING NORTH WITH EDGE OF WAA AND JET MOVING INTO FAR SE ND BY 09Z. RUC ALSO DEVELOPS PCPN TO VALLEY CITY AREA BY 09Z. THIS SEEMS REASONABLE. RADAR MOSIAC SHOWS INCREASING ECHOES OVER SW ND...THOUGH THIS IS LIKELY JUST MID CLDS AND VIRGA ATTM. BUT PREV MODELS SHOWED RAPID MOISTENING OVERNIGHT...BTWN 09 AND 12Z OVER SE ND/WCNTRL MN. CURRENT ZFP WORDING HAS SNOW DEVELOPING AROUND MIDNIGHT GFK/FAR. THIS SEEMS A TAD EARLY AND WILL BACK OFF AND SAY AFTER MIDNIGHT OR LATE. THOUGHT ABOUT DROPPING HEADLING FOR PKD/FFM MN ZONE LATE TONIGHT AND JUST GO WITH TUESDAY SINCE PCPN WILL NOT GET THERE TIL VERY LATE...BUT PCPN OFTEN DEVELOPS QUICK IN STRONG WAA ZONE AND NOT ENOUGH CONFIDENCE TO TINKER WITH PREV ZONE AND WSW WORDING AT THIS TIME. THIS MAY CHANGE WHEN 00Z GUIDANCE ARRIVES. WILL CHECK OVER TEMPS...BUT WILL NEED TO LOWER IN SOME MN ZONES AS TEMPS IN WADENA/PKD ALREADY BLO FCST LOWS. WILL HOLD UPDATE TIL 930 PM OR SO...IN ORDER TO VIEW LATEST MODEL GUIDANCE. WILL UPDATE WSWFAR AT THAT TIME TOO. .FGF...SNOW AND BLOWING SNOW ADVISORY ALONG AND SOUTH OF A LINE FROM VALLEY CITY TO FARGO AND PARK RAPIDS. RIDDLE nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 910 PM CST MON FEB 14 2000 LATEST MESONET DATA SHOWS A FEW STATIONS HAVE ALREADY FALLEN TO OR JUST BELOW FORECAST LOWS TONIGHT SO WILL HAVE TO LOWER TEMPERATURES WITH UPDATE. RUC AND ETA SHOW SURFACE LOW OVER NORTHERN ROCKIES WILL BE CENTERED OVER SOUTHERN SOUTH DAKOTA BY 12Z TUESDAY. SURFACE WINDS WILL REMAIN HIGH ENOUGH...ESPECIALLY ACROSS NORTHWEST...TO KEEP TEMPERATURES FROM FALLING MORE THAN A CATEGORY OR TWO BELOW FORECAST. .OUN... OK...NONE. TX...NONE. 6 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1021 AM CST MON FEB 14 2000 A STRONG ALONG-STREAM VARIATION IN THE UPPER LEVEL WIND SPEED WAS RESPONSIBLE FOR A THICK CIRRUS SHIELD OVER THE FORECAST AREA THIS MORNING. BUT CIRRUS HAS ALREADY THINNED AND RECENT RUC AND ETA GUIDANCE SHOW THE UPPER LEVEL JET SHIFTING EAST QUITE RAPIDLY THIS AFTERNOON WHICH SHOULD RESULT IN THE CONTINUATION OF DECREASING CIRRUS. AS A RESULT MORE SUN SHOULD REACH THE GROUND THAN ORIGINALLY ANTICIPATED AND MAY NEED TO RAISE HIGH TEMPERATURES A LITTLE...ESPECIALLY OUT WEST. OTHERWISE SURFACE RIDGE CENTERED OVER THE AREA WILL ALSO SHIFT EAST THIS AFTERNOON ALLOWING WINDS IN ALL AREAS TO SHIFT TO A SOUTHERLY COMPONENT. SYSTEM MOVING INTO THE PACIFIC NORTHWEST APPEARS STRONGER THAN LAST MODELS INDICATED. MAY RESULT IN STRONGER RETURN FLOW TONIGHT AND EARLY TUESDAY BEFORE A SURFACE LOW DRAGS A WEAK FRONT/TROUGH ACROSS THE FORECAST AREA LATE IN THE DAY. WON'T MAKE ANY CHANGES FOR TUESDAY YET...BUT WILL PASS ALONG THOUGHTS TO THE LONG-TERM FORECASTER. .OUN... OK...NONE. TX...NONE. JAMES ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 910 PM EST MON FEB 14 2000 MAIN CONCERN THIS EVENING IS WHETHER OR NOT LOW CLOUDS WILL CLEAR FORECAST AREA OVERNIGHT. EARLIER BREAKS FROM DOWNSLOPING HAVE FILLED BACK IN...AS CURRENTLY FIND BROKEN TO OVERCAST CEILINGS PREVALENT. WILL LIKELY MAINTAIN EARLIER WORDING AS DECREASING CLOUDS FOR ALL BUT SWRN VA AND NE TN ZONES WHERE LATEST RUC MODEL HANGS ON TO MOISTURE THRU 09Z. STILL POSSIBLE FOR SWRN MOST ZONES TO CLEAR OUT BY DAYBREAK. CLOUDS PERSISTING AND AT LEAST LIGHT NW WINDS MAY HINDER FOG DEVELOPMENT AT TAF SITES...SO MAY BE LESS PESSIMISTIC WITH 06Z TAFS. OTHER ITEM OF INTEREST...IS WILL THERE BE ANY SPRINKLES OR FLURRIES IN SWRN VA/NE TN? WE DO HAVE WEAK PVA/PIVA AND SOME UPSLOPE COMPONENT TO LOW LVL WINDS...PLUS COLD AIR ADVECTION AS 850 MB THERMAL TROF MOVES FROM MIDDLE TN/CNTRL KY INTO NE TN BY 09Z. THUS FAR JUST SOME VERY WEAK CLEAR AIR RETURNS ON 88D...SO WILL LIKELY WORD AS SPRINKLES OR FLURRIES POSSIBLE. UPDATED ZONES...WHERE NEEDED...TO FOLLOW BY AROUND 10 PM EST. .MRX... NC...NONE. TN...NONE. VA...NONE. TG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 840 PM EST MON FEB 14 2000 MOSAIC RDR SHWG AREA OF SNW EXPANDING ACRS NNY AND MOVG INTO NW VT. CONTD MSTR IN NLY FLOW COMBINED WITH H5 S/WV AND ADDED LIFT FM LEFT EXIT OF JET RSLTG IN CRNT AREA OF SNW. RUC RESOLVING THIS FTR WELL AND SHWS S/WV TRACKING ACRS S VT AFT MIDNGT. RUC INDCTG AREA OF 80-90 PCT MEAN RH AND MEAURABLE QPF ASSCD WITH THIS FTR MOVG ACRS N ZNS. 18Z ETA ALSO HINTING AT THIS IN MSTR/QPF FIELDS. SO XPCT AREA OF SNW TO OVRSPRD REST OF N ZNS OVRNGT. BASED ON RDR TRENDS BULK OF SNW SHD PASS N OF S VT SO JUST CHC POPS THERE. SNW MAY BRIEFLY BE HEAVY...ESP ADRNDCKS BASED ON MOD/HVY SNW AT ART/GTB ERLYR. PREV FCST HAD A GOOD GRASP ON THIS WITH ADDITL 1-2" (1-3" ADRNDCKS) TNGT AND SEE NO REASON TO ALTER. WL JUST CLEAN UP THE WORDING A BIT. LWRD TMPS ACRS MST ZNS BASED ON CRNT READINGS AND UPSTRM TMPS IN ONT. .BTV...NONE. KJC vt NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 1040 PM MST MON FEB 14 2000 UPDATED SHORT TERM DISCUSSION: AFTER LOOKING AT LASTEST GRIDDED DATA AM CONCERNED ABOUT PROSPECTS OF BRIEF HIGH WND EVENT LATE TONIGHT INTO TUE MORNING. LATEST CROSS-SECTIONS SHOW COMPONENT ALONG WNDS INCRG TO 50-55 KTS BY 09Z AND CONTINUING THRU ABOUT 15Z. SHEAR PROFILE ACTUALLY IMPROVES OVERNIGHT VERSUS WHAT 12Z DATA SHOWED. STG DISTURBANCE IS ALSO FCST TO MOVE RAPIDLY ACRS WY OVERNIGHT WITH QG DESCENT DVLPG OVR NRN CO BY 12Z. CONSIDERING STRENGTH OF COMPONENT ALONG WNDS SHOWN BY LATEST RUC BELIEVE THAT A HIGH WND WATCH IS NECESSARY ALONG AND NEAR THE FOOTHILLS FOR LATE TONIGHT INTO TUE MRNG. MEANWHILE IN THE MTNS SNOW WL INCR AFTER MIDNIGHT AND WITH EXPECTED STG WNDS WL ISSUE A SNOW AND BLOWING SNOW ADVISORY FOR THE REST OF TONIGHT INTO TUE MRNG FOR AREAS ESPECIALLY N OF I-70. KLEYLA .DEN...HIGH WND WATCH LATE TONIGHT INTO TUE MRNG FOR THE FOOTHILLS AND AREAS WEST OF I-25...ZNS 35..36..38..39 AND 40. ...SNOW AND BLOWING SNOW ADVISORY FOR THE NRN MTNS THRU TUE MRNG...ZNS 33 AND 34. co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 225 AM EST TUE FEB 15 2000 CURRENTLY -- A VIGOROUS VORT MAX IS MOVING E ACROSS THE NRN ROCKIES. OVER THE CWA...WATER VAPOR IMAGES SHOW SUBSIDENT NW FLOW ALOFT IN THE WAKE OF A SHORTWAVE TROUGH MOVING OFF THE SE U.S. COAST. SURFACE FRONT EXTENDED NE THROUGH 40J AT 05Z WITH LOW CLOUDS AND FOG S OF THE FRONT. A BROAD SURFACE HIGH IS CENTERED JUST E OF THE MID MS VALLEY AND HAS BEEN BUILDING SE BEHIND FRONT WITH 10-15 KT WINDS REPORTED ON METARS ALONG OUR NRN AND WRN CWA. --FORECAST -- 04Z RUC ADVERTISES SURGE OF HIGHER PRESSURE TO CONTINUE INTO CWA WITH SURFACE FLOW RAPIDLY VEERING TO NE BY LATE MORNING. FLOW WILL CONTINUE TO RAPIDLY VEER TO THE SE BY THIS EVENING AHEAD OF A SURFACE LOW CROSSING THE NRN PLAINS IN ADVANCE OF THE AFOREMENTIONED VORT MAX. AIR OVER GULF REMAINS JUICY...SO WOULD NOT RULE OUT ADVECTION FOG TONIGHT OVER SW ZONES WITH ONSHORE FLOW. SHORTWAVE TROUGH TO SHEAR E ACROSS OH VALLEY WEDNESDAY WITH LITTLE EXPECTED EFFECTS FOR AREA WEATHER...SO POPS WILL STAY NEAR ZERO. WILL DEVIATE LITTLE FROM GUIDANCE TEMPERATURES. MARINE - SEAS STILL RELATIVELY HIGH AFTER WINDS HAD DROPPED OFF RAPIDLY. EXPECT WAVE HEIGHTS TO CONTINUE A SLOW DECREASE THIS MORNING. NO HIGHLIGHTS EXPECTED. FIRE WEATHER - RED FLAG WARNING WILL BE ISSUED FOR INLAND FLORIDA COUNTIES THIS AFTERNOON FOR LOW RH DURATIONS. EXTENDED - ABOVE NORMAL TEMPERATURES WILL PERSIST WITH MEAN HEIGHT AND THICKNESS RIDGING OVER THE ERN USA THROUGH FRIDAY. MEDIUM RANGE MODELS IN REASONABLE AGREEMENT ABOUT BRINGING A BROAD TROUGH TO THE ERN USA BY SATURDAY. AN ASSOCIATED COLD FRONT SHOULD PASS THROUGH THE CWA BY THE END OF THIS PERIOD...BRINGING A BETTER CHANCE OF RAIN. BEGINNING OF PERIOD HAS SLIGHT CHANCE FOR RAIN MENTIONED. WILL KEEP THIS FOR SAKE OF CONTINUITY. ALL INPUT IS WELCOME. PRELIMINARY NUMBERS... TLH 072/046 079/054 000- PFN 070/053 072/055 00-1 DHN 072/053 074/052 00-1 ABY 069/049 074/053 000- VLD 071/045 075/051 00-- .TLH... AL...NONE. GA...NONE. FL...RED FLAG WARNING INLAND COUNTIES THIS AFTN. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 238 AM CST TUE FEB 15 2000 SFC HIGH PRESSURE WAS OVER THE OHIO AND MISSISSIPPI VALLEY REGIONS PER THE 07Z ANALYSIS. STRATO-CU WAS EAST OF A LINE FROM KMVN TO KHOP PER FOG IMAGERY...WITH BLOOMFIELD PROFILER AND RUC SHOWING LESS THAN 10KTS MEAN WIND BELOW 3K FT. RUC ADVERTISES THAT THE 925MB RIDGE WILL SHIFT EAST AROUND 12Z AND ALLOW A SOUTHERLY 10 TO 20KT FLOW TO DEVELOP. THIS SHOULD RID THE CLOUDS QUICKLY IN EAST SECTIONS. LONGER TERM FORECAST CONCERN IS WITH THE MODELS SLOWING THE ONSET OF RAIN OVER THE FA WEDNESDAY INTO THURSDAY. AVN WILL BE MODEL OF CHOICE...EVEN THOUGH IT HAS CHANGED CONSIDERABLY FROM THE 12Z RUN. IT DOES JIVE FAIRLY WELL WITH THE ETA. FOR THE REST OF TODAY...WK MID-LVL S/WV TROF WILL MOVE ESE FROM THE NORTHERN PLAINS TO OVER THE OHIO VALLEY BY THIS EVENING. ACCOMPANIED WITH IT WILL BE A GOOD LOW-LVL JET OF 40KTS DVLPG THIS AFTERNOON...AND INCREASED RH. AVN ADVERTISES GOOD H8/H7 Q-CONVERGENCE/WAA WITH SAME LAYER AVG MSTR OVER 60% NORTH 1/2 OF FA. WILL GO WITH PARTLY SUNNY EVERYWHERE. THERE MAY BE A SPRINKLE OR TWO EXTREME NORTH...BUT WILL NOT MENTION FOR NOW AND LET LATER SHIFTS HANDLE. BETTER CHC WILL BE NORTH OF OUR CWFA. GUIDANCE IS RUNNING SLIGHTLY COOLER THAN ZFP NOS FOR 2 CONSECUTIVE RUNS NOW AND WILL FOLLOW. FOR TONIGHT...A COLD FRONT WILL PASS THROUGH LATE AS SFC LOW PRESSURE MOVES FROM WISCONSIN TO SOUTHERN ONTARIO. IT IS FORECAST TO EXIT EASTERN COUNTIES TOWARD DAYBREAK. BOUNDARY LAYER THERMAL RIDGE AHEAD OF FEATURE WILL KEEP MINS UP TONIGHT. FWC/FAN APPEAR ON TRACK. LOOKING WELL UPSTREAM ON NA IR SATELLITE...AND AVN TSCTS...WILL MAINTAIN PARTLY CLOUDY. BIG MODEL DIFFERENCES WEDNESDAY. LATEST AVN HAS SFC HI BUILDING IN MUCH STRONGER THAN PREVIOUS RUNS...AND LINES UP WITH THE ETA. BY 06Z THU THE AVN HAS THE SURFACE FRONT FROM THE CAROLINAS ACROSS MISSISSIPPI INTO SRN OKLAHOMA. BASED ON ETA/AVN AGREEMENT...WILL HAVE TO REMOVE POPS FOR SE MO ON WEDNESDAY...LOWER TEMPS WEDNESDAY/WEDNESDAY NIGHT AND DELAY ONSET OF RAIN UNTIL LATE WEDNESDAY NIGHT FOR SOUTHERN SECTIONS. AVN BEYOND 48HRS FINALLY BRINGS THE FRONT UP TO THE KY/TN MO/AR BORDER BY THU AFTN. CURRENT EXTENDED FORECAST OF SHRA/TSRA FOR THU AND FRI STILL LOOKS GOOD. MODELS ADVERTISE SEVERAL WEAK IMPULSES WILL EJECT TOWARD THE AREA FROM AN APPROACHING UPPER LOW FROM THE SW U.S...AND INTERACT WITH FRONT DRAPED ACROSS OUR AREA. .PAH...NONE. CN ky FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 300 AM CST TUE FEB 15 2000 ...MAIN FORECAST CHALLENGE CONCERNS DEVELOPING WINTER WEATHER... MODELS IN DECENT AGREEMENT WITH MOVEMENT OF 5H S/W ACROSS THE NRN PLAINS. THE ETA HAS SHIFTED TRACK OF SFC LOW FURTHER N FROM PREVIOUS 0Z AND 12Z RUNS...WITH RUC IN SUPPORT OF FURTHER N TRACK BUT SLOWER IN MOVEMENT. AVN AND NGM SLOWER AND AVN NOW FURTHER SOUTH WITH SFC LOW. CONSIDERING LOCATION OF BAROCLINIC ZONE AND SFC FRONT FROM U/A AND SFC ANALYSIS...FURTHER N POSITION OF ETA/RUC PREFERRED. FOR TIMING WILL FOLLOW SLOWER AVN/RUC. .SHORT TERM...REGIONAL WSR-88D DATA SHOWS BAND OF SNOW EXTENDING FROM WRN ND INTO SE MN THIS AM WHICH CORRELATES WELL WITH AREA OF BEST 280K ISENTROPIC LIFT PER THE AVN/ETA. FOLLOWING THIS...WITH ADJUSTMENTS...MAX LIFT TO STRETCH ACROSS SE ND INTO WEST CENTRAL MN BY 12Z WITH SPECIFIC HUMIDITIES EXCEEDING 2 G/KG IN THAT LOCATION. 700 MB CONDENSATION PRESSURE DEFICITS MINIMIZE AT THAT TIME AS WELL. PWAT APPROACHING .5 INCH JUST SOUTH OF THE BORDER...WITH 24 HR PCPN ACCUMULATIONS EXCEEDING .20 INCH ACROSS EXTREME SRN FA. BEST CASE SCENARIO USING GARCIA AND TEMP/MELTWATER EQUIVALENT SUPPORTS SNOW ACCUMULATIONS OF 4 TO 6 INCHES IN THIS AREA. FAST MOVEMENT OF SYSTEM AND DELAY OF SATURATION OF BOUNDARY LAYER FOR A TIME SUGGESTS SLIGHTLY LOWER SNOWFALL AMOUNTS WITH ONGOING 3 TO 5 INCHES REASONABLE...WITH AMOUNTS DROPPING OFF QUICKLY NORTH OF THIS AREA. SNOW TO END QUICKLY FROM WEST TO EAST DURING THE MORNING AS DOWNGLIDE SPREADS ACROSS THE FA. MSAS DATA SHOWS SFC LOW TO BE DEEPER THAN DEPICTED BY ETA/AVN WITH RUC THE BEST. THUS EXPECT SFC WINDS TO BE STRONGER THAN INDICATED BY THE MODELS...WITH 15 TO 25 MPH REASONABLE OVER THE SRN FA. SNOW FROM THIS AND PREVIOUS EVENTS SHOULD BLOW AROUND ENOUGH TO RESTRICT VISIBILITIES BUT PERHAPS NOT QUITE ENOUGH TO KEEP BLOWING SNOW ADVISORY GOING IN ADDITIONS TO SNOW ADVISORY. TO KEEP CONTINUITY... HAVE DECIDED TO CONTINUE CURRENT ADVISORY AS WRITTEN. TEMP FORECAST ON TRACK AS WELL SO NO CHANGES THERE. .LONG TERM...HIGH PRESSURE BUILDS IN FROM THE NORTHWEST AND WILL PREVAIL ACROSS THE REGION THROUGH 48 HRS. PREFER COOLER FWC NUMBERS AS NGM/ETA 1000 TO 850 MB THICKNESSES RUNNING LOWER THAN AVN AND WITH EXPECTED SNOW COVER. .EXTENDED...NEW MRF STILL SHOWING INVERTED SFC TROF MOVING ACROSS THE NRN PLAINS AS CLIPPER LIKE SYSTEM DROPS IN FROM THE NORTHWEST. WILL KEEP ONGOING SNOW FORECAST FOR EARLY IN THE EXTENDED. MRF HINTING AT BRINGING ANOTHER SYSTEM THROUGH SAT...BUT THIS IS NOT SUPPORTED BY NEW CANADIAN RUN. THIS WILL NOT MAKE CHANGES TO CURRENT EXTENDED ATTM. .FGF...SNOW AND BLOWING SNOW ADVISORY TODAY ALONG AND SOUTH OF A LINE FROM VALLEY CITY TO FARGO TO PARK RAPIDS. RJT nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI ISSUED BY NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1130 AM EST TUE FEB 15 2000 WAA/ISENTROPIC LIFT SNOW ENTERING WRN MI ATTM AND HAS A NEWD DRIFT. LATEST RUC AND NEW 12Z ETA SUPPORTS GOING IDEA OF BEST PCPN CHCS IN THE EXTREME NRN PORTION OF SE LWR THIS AFTERNOON. WILL CONTINUE THE GOING FCST OF SNOW DEVELOPING ACROSS BAY/HURON/MIDLAND COUNTIES AND HOLD OFF ON ANY MENTION OF ACCUMULATIONS UNTIL TONIGHT. PCPN CHCS LOWER CONSIDERABLY FARTHER SOUTH THIS AFTERNOON ACROSS SE LWR MI WHERE RUC PROGS HIGHER CONDENSATION PRESSURE DEFICITS. 12Z DTX SOUNDING ALSO VERY DRY BELOW 500 MB. WILL MAINTAIN CHANCE POPS IN FNT AREA BUT KEEP THE SRN AREAS DRY...ALTHOUGH A SPRINKLE OR FLURRY SEEMS POSSIBLE AS TAIL END OF WAA PCPN DRIFTS ACROSS. RUC SHOWS SIGNIFICANT WARMING SURGING IN AT 850 MB THIS AFTERNOON SUGGESTING MORE OF A MIXY PCPN SCENERIO COULD SET UP BY EVENING. HOWEVER HOURLY FCST SOUNDINGS SHOW WET BULB PROFILES REMAINING BELOW ZERO SO WILL KEEP PCPN TYPE ALL SNOW. 3.9 MICRON AND VISIBLE SATELLITE IMAGERY SHOWS A LARGE HOLE IN THE LOW CLOUDS OPENING UP OVER SE LWR MI AND NW OH. WILL HAVE TO ACCOUNT FOR THIS EARLY ON...AND IT MAY IMPACT HIGH TEMPS AS WELL. PCPN CHANCES LOOK MUCH BETTER FOR ALL OF SE LWR TONIGHT AS SHORT WAVE TROUGH COMES THROUGH. .DTX...NONE. MEADE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 922 AM CST TUE FEB 15 2000 14Z SURFACE OBSERVATIONS AND SATELLITE IMAGERY SHOWING MAIN ENERGY ACROSS THE DAKOTAS. SNOW ASSOCIATED WITH THERMODYNAMIC FORCING HAS MOVED EAST OF THE FORECAST AREA. THUS...ONLY REMAINING CHANCE OF SNOW WILL BE FROM THE DAKOTA DISTURBANCE. 12Z RUC HAS GOOD HANDLE ON SNOW ASSOCIATED WITH THE SYSTEMS DYNAMIC FORCING. AT THE PRESENT TIME...LOOKS AS THOUGH THE HEAVIEST SNOW WILL REMAIN NORTH OF THE FORECAST AREA. NEVER THE LESS...WILL HOLD ON TO CURRENT HEADLINES AS POSTED UNTIL THE STORM PASSES. WILL INDICATE A LESSER EVENT THAN CURRENTLY ADVERTISED FOR AREAS NEAR AND SOUTH OF ROCHESTER AND LA CROSSE. .LSE...WINTER STORM WARNING...TODAY...NORTH CENTRAL WI...WIZ017. WINTER WEATHER ADVISORY TODAY...CENTRAL WI...WIZ029. KRC wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 245 PM CST TUE FEB 15 2000 ...SHORT TERM... WATER VAPOR AND PROFILER DATA SHOW A VIGOROUS SHORTWAVE MOVING ACROSS MINNESOTA INTO WISCONSIN. AHEAD OF THE SHORTWAVE A STRONG LLJ OF 45-55 KNOTS RAN FROM NORTHERN TEXAS INTO WISCONSIN ADVECTING WARMER AIR INTO THE REGION. DARKENING IN THE WATER VAPOR IMAGE ACROSS EASTERN COLORADO/WESTERN NEBRASKA INDICATES THE PASSAGE OF ANOTHER SHORTWAVE THERE AS WELL BEING AIDED BY A JET STREAK OF 110 KNOTS AT 300 MB. SATELLITE SHOWS MAINLY CI/CS ACROSS THE AREA WITH THE MAIN SYSTEM CLOUDS STAYING NORTH OF THE AREA FOR THE MOMENT. RADAR MOSAIC SHOWS SOME RETURNS ACROSS WISCONSIN/NORTHEAST ILLINOIS WHICH ARE AREAS OF MID LEVEL CLOUDS. 18Z SURFACE ANALYSIS HAS THE LOW NEAR KJYG WITH THE WARM FRONT EXTENDING NORTHEAST TOWARD KEAU AND THEN ACROSS CENTRAL WISCONSIN. THE COLD FRONT RUNS SOUTHWEST TOWARD KSUX AND THEN WEST ACROSS SOUTH DAKOTA. SURFACE DATA ALSO SHOWS THE PRESENCE OF TWO TROFS...ONE RUNNING FROM THE LOW TO NEAR KAMA WHICH IS A REFLECTION OF SHORTWAVE EXITING COLORADO INTO KANSAS...AND ANOTHER FROM THE LOW TO EAST OF I35 INTO NORTHERN MISSOURI WHICH IS A REFLECTION OF A WEAK SHORTWAVE MOVING ACROSS IOWA. MOISTURE ANALYSIS HAS DEW POINTS IN THE 30S ACROSS IOWA AND MOST OF ILLINOIS WITH 20S AND TEENS BEHIND THE LOW IN THE DAKOTAS. PROBLEMS THIS PACKAGE ARE CLOUDS/TEMPERATURES AND NEXT PRECIP CHANCES. 12Z MODELS DID NOT INITIALIZE WELL AND THIS IS REFLECTED IN THEIR RESPECTIVE 6 HR FORECASTS. ALL MODELS PLACE THE SURFACE LOW IN MINNESOTA TOO FAR SOUTH WITH THE ETA BEING THE CLOSEST BUT STILL IN IOWA. NONE OF THE MODELS INITIALIZED THE MATURE SYSTEM OFF THE COAST OF CALIFORNIA IN THE CORRECT PLACE OR STRENGTH. WATER VAPOR SHOWS THE SYSTEM FURTHER TO THE SOUTH AND A VERY HELPFUL AIRCRAFT REPORT INDICATES 90 KNOTS WINDS. THE ERRORS OF PLACEMENT/STRENGTH OF THIS SYSTEM PLAY SIGNIFICANTLY LATER IN THE FORECAST PACKAGE. THE 15Z/18Z RUC IS PLACING FEATURES THE BEST SO WILL FOLLOW THEM FOR THE VERY SHORT TERM AND THEN DECIDE WHICH SOLUTION TO BELIEVE FOR FARTHER OUT. RUC KEEPS UPPER MISSISSIPPI SYSTEM WELL NORTH OF THE AREA WHILE A TRAILING SHORTWAVE DROPS SOUTHEAST BEHIND IT. RUC SHOWS CURRENT ST/SC OVER THE DAKOTAS MOVING INTO THE AREA TONIGHT WITH SLIGHTLY LOWER CONDENSATION PRESSURE DEFICITS OVER ABOUT THE NORTH HALF. THIS SHOULD BE ENOUGH TO ALLOW A FEW FLURRIES TO DEVELOP MAINLY NORTH OF I80. AFTER TONIGHT USED A AVN/ETA BLEND WITH A TAD MORE EMPHASIS ON THE AVN. LOW CLOUDS TO BREAK OUT DURING THE DAY TOMORROW SO SOME SUN SHOULD BE SEEN WEDNESDAY. HIGH LEVEL MOISTURE BEINGS MOVING IN WEDNESDAY NIGHT WITH SOME LIFT OCCURRING. HOWEVER SOUNDING PROFILES SHOW DRY AIR IN THE LOW LEVELS SO THE AVN/ETA IDEA OF HAVING PRECIP IN HERE BY THURSDAY AM LOOKS FALSE. TREND IN MODELS LATELY HAS BEEN TO PLACE SYSTEMS TOO FAR NORTH AND ENSEMBLES WOULD INDICATE A SLIGHTLY FURTHER SOUTH POSITION OF THE SYSTEM FOR THURSDAY/FRIDAY. ON THURSDAY AFTER 850 MB RIDGE MOVES EAST OF THE AREA ISENTROPIC LIFT STARTS IN ERNEST WITH 100 MB OF LIFT OVER THE AREA AND A LLJ OF 40-50 KNOTS FROM LOUISIANA INTO ILLINOIS. ATMOSPHERE TO RAPIDLY SATURATE DURING THE DAY THURSDAY AND EVAPORATIVELY COOL SOMEWHAT WITH --SN/-SN BREAKING OUT DURING THURSDAY AFTERNOON. THIS CONTINUES INTO THURSDAY NIGHT AND FIRST PART OF THE EXTENDED WITH WHAT HAS THE MAKING OF SOME SIGNIFICANT SNOWFALL ACROSS THE AREA. DUE TO THIS POSSIBILITY WILL ISSUE A NEW SIGNIFICANT WEATHER OUTLOOK. TEMPERATURE WISE FWC/FAN NUMBERS ARE FAIRLY CLOSE BUT WITH SOME EXPECTED CLOUDS TONIGHT MINS SHOULD BE SOMEWHAT HIGHER. AFTER THAT THE QUESTION IS HOW MUCH ARCTIC AIR GETS INTO THE AREA. BELIEVE GUIDANCE MIGHT BE A LITTLE TOO COLD WEDNESDAY NIGHT. ...EXTENDED... FIRST PART OF EXTENDED TO BE BUSY WITH DEPARTING SYSTEM ON FRIDAY. AFTER THAT ANOTHER CANADIAN HIGH BUILDS INTO THE AREA BRINGING QUIET CONDITIONS TO THE AREA. IF MEDIUM RANGE MODELS ARE CORRECT... NOT MUCH IN THE WAY OF ARCTIC AIR TO FOLLOW BEHIND THE THURSDAY/FRIDAY SYSTEM. COORDINATED WITH DSM...LSE...CHI...ILX...AND STL. .DVN...NONE. NC il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 430 PM EST TUE FEB 15 2000 MAIN FCST CONCERNS PACKAGE SHIFT FROM ONGOING HEAVY SNOW EVENT THIS EVENING TO LAKE EFFECT SNOW POTENTIAL LATE TONIGHT INTO WEDNESDAY NIGHT. WV/IR IMAGERY SHOWED STRONG VORT TO NE MN WITH IMPRESSIVE SHIELD OF COLD CLOUD TOPS ACRS UPR MI AND LK SUPERIOR. AT THE SFC...LO PRES WAS NEAR RST AT 20Z WITH GREATEST PRESSURE FALLS FROM NRN IL INTO SE WI. COMPOSITE RADAR AND SFC OBS INDICATED HEAVIEST SNOW IN FAVORED POSITION NEAR SRN PORTION OF COLDER TOPS WITH VSBYS AOB 1/2SM AND SNOWFALL RATES AOA 1 INCH/HR. SNOWFALL REPORTS INDICATED 5-7 INCH AMOUNTS ALREADY OVER NRN WI AND WRN UPR MI WITH 2 TO 4 INCH AMOUNTS MQT TO IMT-ESC AND CRYSTAL FALLS. HEAVY SNOWFALL SUPPORTED BY STRONG UPR LVL DIV...850-500 QVECTOR CONVERGENCE AND 290K-300K ISENTROPIC ASCENT AHEAD OF POTENT SHRTWV. IN THE SHORT TERM...MDLS IN REASONABLE AGREEMENT IN HANDLING SYSTEM AS IT PASSES THROUGH THE AREA. HOWEVER...TREND WITH THE VORT HAS BEEN TOWARD A TRACK A BIT FARTHER TO THE NORTH...PER WV LOOP...RADAR AND 18Z RUC. EXPECT SNOW TO LINGER TIL BACK EDGE OF FORCING ASSOCIATED WITH SHRTWV MOVES THROUGH THE AREA BTWN 00Z-06Z. SOME LAKE ENHANCEMENT COULD ADD TO THE ALREADY IMPRESSIVE SYNOPTIC TOTALS. AS LLVL WINDS VEER FROM THE EAST TO THE NORTHEAST AND NORTH OVERNIGHT WITH LK-H85 DLT/T AROUND 12C...ADDED MOISTURE AND UPSLOPE FLOW SHOULD BOOST SNOWFALL...PARTICULARLY FOR HIGHER TERRAIN NEAR IWD AND MQT. HRLY BUFKIT WINDS SHOW DEPTH OF NE FLOW INCREASING FROM 00Z-06Z DURING SAME PERIOD BEST LIFT IS DEPARTING. THIS WOULD LEAVE BEST WINDOW FOR ENHANCEMENT FROM 02Z-05Z. PROCESS ALREADY UNDERWAY NEAR IWD...PER KDLH VWP. SO...WILL ADD ANOTHER 1-3 INCHES ONTO SYNOPTIC AMOUNTS. SNOW WILL TRANSITION TO PURE LES BTWN 06Z-12Z AS DLT/T LOWERS TO 18C...SUBSIDENCE INCREASES AND INVERSION HGTS LOWER TO 3-4K FT AS WINDS VEER TOWARD 340. WEDNESDAY...WINDS AROUND 340 FCST TO GRADUALLY BACK TOWARD 300. ONT-P59 AND AREAS EAST OF MARQUETTE WILL BE FAVORED FOR LES AS DLT/T DROPS TO AROUND 20C. WL GO WITH LIGHTER AMOUNTS THAN SUGGESTED BY DECISION TREE GIVEN CONTINUED LOW INVERSION HGTS NEAR 3K FEET WITH STRONG SUBSIDENCE AND 850-700 DRYING. LONGER FETCH INTO ERN UPR MI SHOULD BRING POTENTIAL FOR SLIGHTLY GREATER AMOUNTS THAN WRN UPR MI. WEDNESDAY NIGHT INTO THURSDAY NIGHT...ANY LINGERING LES WINDS DOWN EARLY WED NIGHT WITH BACKING WINDS AND WAA SETTING IN. ADDED MENTION OF CHANCE POPS FOR LATE THUR WEST AND ACRS AREA THURSDAY NIGHT AHEAD OF NEXT WEAK SHRTWV MOVING TOWARD AREA...PER ETA AND 48-72 HR AVN. EXTENDED...MDLS IN REASONABLE AGREEMENT WITH KEEPING UPR MI IN A GENERALLY DRY PATTERN ONLY AFFECTED BY WEAK NRN STREAM SHRTWVS. ENOUGH COLD AIR FOR WEAK LES MAINLY FRIDAY. .MQT...WINTER STORM WARNING TONIGHT MIZ002-005-009 ...WINTER STORM WARNING TONIGHT INTO WEDNESDAY MIZ006 ...SNOW ADVISORY EARLY TONIGHT MIZ004-007-010>014 JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1210 PM EST TUE FEB 15 2000 ...SN ENTERING UPR MI... 88D RETURNS AND METARS NOW SHOWING BROAD AREA OF SN W/ VSBY BLO 1SM BEGINNING TO ENTER THE SOUTHWEST FA ATTM. SFC OBS AND SPOTTER REPORTS SUBSTANTIATE THIS AS SN NOW REPORTED AT ASX...IWD...IRON RIVER...AND IMT. TIGHTLY WOUND VORT MAX OVR NRN MN CONTINUES TO PUSH EAST AS DIPICTED BY WV AND IMPRESSIVE BAROCLINIC LEAF ON IR SAT. VORT IS REFLECTED BY TIGHTLY PACKED STORM W/ CENTRAL PRESSURE OF 1000MB OVER SOUTHWESTERN MN ATTM. SFC ANALYSIS THIS MORNING REVEAL STORM HAS MOVED ABOUT 200 MILES SINCE 12Z THIS MORNING FM SCENTRAL ND. LOW IS MOVING EAST OR SLIGHTLY NORTHEAST TOWARDS BEST 3HR PRES FALLS OF 4MB OVR W CENTRAL WI PER MSAS ANALYSIS. SN WL SPREAD FM WEST TO EAST THIS AFTERNOON AND WL HAVE LITTLE DIFFICULTY GETTING GOING WITH RELATIVELY MOIST BLYR IN PLACE. NEW MODEL QPFS ARE SIMILAR TO PREVIOUS RUNS AND SHRT TERM MODELS (MESOETA AND RUC) STILL POINT TO NARROW STRIPE OF HEAVIEST SNOWFALL ACROSS S CENTRAL UPPER MI FM IWD TO IMT TO ESC...WHERE 3 TO 5 INCHES SHOULD FALL BY EVENING. ACROSS NW BELIEVE AMOUNTS WL BE MORE IN LINE W/ 2-4 INCHES IN ONT AND THE KEWEENAW. SINCE MAJORITY OF SN HAS JUST BEGUN ACROSS WESTERN UPR PENINSULA SN AMOUNTS WL GO RELATIVELY UNCHANGED FM PREVIOUS ZONE PKG...WITH ONLY EXCEPTION OUT EAST IN SCHOOLCRAFT COUNTY WHERE AMOUNTS WERE TRIMMED SLGTLY THIS AFTN AND BUMPED UP SLGTLY TONIGHT. .MQT...WINTER STORM WARNING THIS AFTERNOON AND TONIGHT MIZ005 ...WINTER STORM WARNING THIS AFTERNOON THROUGH WEDNESDAY MIZ006 ...SNOW ADVISORY MIZ002-004-007-009>014 JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 315 PM CST TUE FEB 15 2000 THE SNOW CONTINUES TO PILE UP...WITH LAKE SUPERIOR BECOMING INVOLVED NOW. AMOUNTS WILL HAVE TO BE ADJUSTED UPWARD AGAIN. ANOTHER BAND OF HEAVY SNOW JUST FORMED WEST OF THE TWIN PORTS. WILL KEEP THE WARNING GOING FOR THE TWIN PORTS INTO THE EVENING. WILL ALSO KEEP THE WARNING GOING FROM BAYFIELD INTO IRON COUNTIES...AS CONDITIONS BECOME MORE FAVORABLE FOR LAKE EFFECT/LAKE ENHANCEMENT. MODELS WERE FAIRLY CLOSE ON THE VORT PLACEMENT. WILL CONTINUE TO GO WITH THE RUC...WHICH DID A BEAUTIFUL JOB ON THE QPF FIELDS TODAY. BEYOND THAT...WILL STICK WITH AVN DUE TO LIMITED FORECAST TIME. VORT NOW MOVING THROUGH CENTRAL MINNESOTA. THE MAIN EFFECTS OF THE VORT SHOULD MOVE OUT OF THE MINNESOTA SIDE BY 7 PM...AND NORTHWEST WISCONSIN BY MIDNIGHT. STILL SOME CONCERN ABOUT THE SOUTH SHORE ZONES. WILL UP THE SNOWFALL AMOUNTS IN THE NORTHERN COUNTIES OF WISCONSIN...WITH 10 INCH AMOUNTS JUST RECEIVED FROM HURLEY AND UPSON. WILL BE PESSIMISTIC IN BRINGING CLEARING TO THE SOUTHERN HALF OF THE CWA TONIGHT...ESSENTIALLY DUE TO THE SHORTWAVE MOVING THROUGH THE DAKOTAS. THE NORTHERN ZONES SHOULD SEE SOME PARTIAL CLEARING WITH STRONG NVA. MAY STILL SEE SOME PARTIAL CLEARING IN THE SOUTH...BUT FOR NOW WILL GO WITH MORE CLOUDS. FAN/FWC TEMPS FAIRLY CLOSE AND HAVE NOT STRAYED TOO FAR. NEXT PROBLEM IS CHANCE OF SNOW LATE WEDNESDAY NIGHT AND THURSDAY. WILL GO WITH MID RANGE POPS TO START THE BALL ROLLING IN THE SOUTH. THE SYSTEMS OF LATE HAVE BEEN EFFICIENT SNOW PRODUCERS...OBVIOUSLY. SO WILL BUMP UP FAN/FWC POPS A BIT. .DLH...HEAVY SNOW WARNING THIS EVENING MNZ037-WIZ001. HEAVY SNOW WARNING TONIGHT WIZ002>004. DAP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1215 PM CST TUE FEB 15 2000 SNOW CONTINUED TO PILE UP ACROSS CENTRAL MINNESOTA AND NORTHWEST WISCONSIN THIS MORNING. RUC WAS DOING A TERRIFIC JOB WITH THE PLACEMENT OF THE QPF FIELDS...BUT ONLY HINTED AT THE VORT MOVING THROUGH AITKIN COUNTY. SNOWFALL RATES HAVE BEEN ON THE ORDER OF 2 INCHES AN HOUR IN DULUTH WITH 35 TO 40 DBZ RETURNS ON DLH RADAR AT TIMES. HAVE UPGRADED CARLTON AND SOUTHERN SAINT LOUIS...AS WELL AS THE FOUR NORTHERN MOST COUNTIES IN WISCONSIN TO A HEAVY SNOW WARNING. .DLH...HEAVY SNOW WARNING MNZ037-038-WIZ001>004-006>009. SNOW ADVISORY MNZ025-033>036. DAP mn AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA NATIONAL WEATHER SERVICE ABERDEEN SD 1020 AM CST TUE FEB 15 2000 WRAPAROUND -SN FROM FIRST S/W AND THE INFLUENCES FROM A WEAKER S/W ROTATING THRU THIS AFTN WILL CONTINUE TO BRING -SN TO NC AND NE SD AND WC MN. ADDITIONAL ACCUMULATIONS OF 1 TO 2 INCHES ARE POSSIBLE. THE RUC...ETA AND NGM ALSO SHOW A THIRD S/W MOVING ACROSS THE CWA THIS EVENING. THEREFORE...-SN WILL CONTINUE INTO THIS EVENING ACROSS THE NORTH WITH A CHC ACROSS THE REST OF THE CWA. WITH LOW CLOUDS AND CAA...TEMPS WILL SLOWLY FALL THROUGH THE AFTN. NE WINDS AT 15 TO 30 MPH WILL GENERATE SOME BLOWING SNOW...ESPECIALLY IN NE SD AND WC MN. UPDATED FORECAST TO MAKE MANY CHANGES. .ABR...NONE MOHR sd