WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN 235 PM EST WED JAN 15 2003 ...CURRENTLY... BROAD MID AND UPPER LEVEL TROUGH EXTENDS FROM THE NORTHERN PLAINS INTO THE MID-MISSISSIPPI RIVER VALLEY...INTO THE SOUTHEAST AND OUT INTO THE ATLANTIC. NEXT SERIES OF SHORT-WAVES TO AFFECT THE AREA APPARENT ON WATER VAPOR AND CONFIRMED BY RUC ANALYSIS...ONE IN WYOMING AND COLORADO WITH ANOTHER RIGHT ON ITS HEELS JUST ENTERING MONTANA. CLOSER TO HOME...HIGH PRESSURE CENTERED OVER THE TENNESSEE RIVER VALLEY PROVIDING A NORTHERLY FLOW OVER THE PENINSULA. THIS HAS RESULTED IN SEASONABLY COOL TEMPERATURES FOR THIS AFTERNOON WITH MID TO UPPER 60S ACROSS MOST LOCALES. DEWPOINTS HAVE UNDERGONE A SUBSTANTIAL DECREASE OVER THE LAST HOUR WITH NORTHERN SECTIONS DROPPING SOME 5 DEGREES. LOOKING AT LOCAL OBS...IT LOOKS AS IF MOST SITES WENT BELOW 35% RH A LITTLE AFTER 1 PM. THIS WILL MAKE IT DIFFICULT FOR DURATIONS TO BE MET BEFORE AFTERNOON COOL-DOWN... ALTHOUGH IT WILL BE CLOSE. ...SHORT TERM... LIKE LAST NIGHT...AND THIS UPCOMING WEEKEND...THIS FORECAST WILL BE MOSTLY A TEMPERATURE FORECAST. WINDS WILL DECOUPLE FOR THE MOST PART TONIGHT...BUT WITH HIGH CENTERED OVER THE CAROLINAS...NOT A PERFECT RADIATIONAL NIGHT. WILL STICK PRETTY CLOSE TO GUIDANCE...WHICH GIVES ME AROUND FREEZING TEMPS FOR LEVY...AND WORD FOR THE NORMALLY COLD POCKETS IN THE UPPER 20S. WILL HOLD OFF ON ANY FREEZE WARNINGS AT THIS POINT AS DURATIONS WILL BE HARD TO COME BY ONCE AGAIN. SURFACE WINDS TO ACQUIRE AN EASTERLY COMPONENT LATE AS WINDS AT 850 MB GO SOUTHERLY. WITH THESE TWO VARIABLES GOING AGAINST LONG DURATION FREEZING TEMPERATURES...FEEL FREEZE WARNING MAY BE HARD TO COME BY. ...THURSDAY THROUGH SATURDAY... SHORT WAVES OVER THE NORTHERN PLAINS CONSOLIDATE AS THEY MOVE SOUTHEASTWARD INTO ARKANSAS. ETA HAS BEEN A BIT MORE PROGRESSIVE WITH THIS SYSTEM THAN THE GFS WITH THE GFS TRENDING IN THAT DIRECTION. ETA ALSO MORE AGGRESSIVE WITH MOISTURE FIELDS AND ASSOCIATED PRECIP FOR THURSDAY NIGHT. RIGHT NOW...FAVOR THE PROGRESSIVE SOLUTION DUE TO THE GFS TRENDING AND WILL KEEP SLIGHT CHANCE POPS CURRENTLY ADVERTISED IN FORECAST. TIMING WILL BE THE ONLY CHANGE IN CURRENT PACKAGE AND WILL END PRECIP EARLIER. ONCE FRONT COMES THROUGH...WILL ONCE AGAIN BE DEALING WITH COLD TEMPERATURES FRIDAY NIGHT INTO SATURDAY MORNING. WINDS STAY UP THROUGH THE NIGHTTIME...BUT WILL STILL BE ADVECTING BELOW FREEZING TEMPERATURES INTO THE NORTHERN AND CENTRAL PORTIONS OF THE CWA...THE FIRST PURELY ADVECTIVE FREEZE IN AWHILE. WINDS AT 850 MB REMAIN OFF THE GULF THIS TIME PERIOD WHICH GIVES CAUSE FOR CONCERN AS WELL CIRRUS PROGGED TO MOVE IN LATE. WILL KEEP A BROAD RANGE OF TEMPERATURES IN AT THIS POINT...GOING A SHADE BELOW GUIDANCE...GIVING FUTURE SHIFTS A LITTLE WIGGLE ROOM. ...EXTENDED... GUIDANCE HAS STEADY RISE IN TEMPS...ESPECIALLY MORNING LOWS FOR SUNDAY AND MONDAY. ALTHOUGH AIRMASS MAY SLOWLY MODERATE DURING THIS TIME PERIOD...RADIATIONAL COOLING WILL BECOME THE DOMINANT FEATURE... AND BELIEVE TEMPS COULD BE JUST AS COLD ON THESE MORNINGS. AFTER BRIEF WARM-UP TUESDAY AND WEDNESDAY...GFS BRINGS TRULY ARCTIC AIRMASS DEEP INTO THE CENTRAL U.S. AND THEN EASTWARD. OTHER EXTENDED GUIDANCE NOT NEARLY AS AGGRESSIVE...SO WILL HAVE TO MONITOR THE EVOLUTION OVER THE NEXT SEVERAL DAYS. RIGHT NOW FAVOR THE HIGHER RESOLUTION MODELS...BUT EVEN THEY HAVE SOME DIFFICULTY ON PICKING UP ON SHALLOW DENSE AIRMASS. ...MARINE... TRANQUIL CONDITIONS EXPECTED THE NEXT 36 HOURS...BEFORE NEXT FRONT COMES THROUGH. USUALLY I CAN SHAVE OFF ABOUT 5 TO 10 KNOTS FROM THE GFS MODEL FOR WIND SPEEDS...BUT ALL SHORT RANGE MODELS ARE PROGGING EQUALLY STRONG WINDS. WILL HOLD WINDS AT 20 TO 25 KNOTS BUT START THEM THURSDAY NIGHT. MAY NEED TO BUMP WINDS UPWARD WITH FUTURE ISSUANCES IF MODELS CONTINUE TRENDS. ...FIRE WEATHER... NO FLAGS EXPECTED. PRELIMINARY #'S BKV 029/068 045/053 0010 TPA 042/067 049/056 0011 GIF 044/072 050/058 0011 SRQ 042/068 050/060 0011 FMY 044/072 055/065 0001 .TBW...FIRE WEATHER WATCH THIS AFTERNOON ALL AREAS...EXCEPT IMMEDIATE COAST. JTD fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 850 PM CST WED JAN 15 2003 WILL MAKE SOME MINOR CHANGES TO OVERNIGHT PRECIP WORDING/TIMING IN UPDATE...BUT OTHER THAN THAT...NO SIG CHANGES PLANNED IN ADVSY/WARNING AREAS. 02Z SFC ANALYSIS INDICATING LOW PRESSURE OVR NRN TEXAS SHIFTING SEWD. BEST 3 HOURLY PRESSURE FALLS ACRS ERN OK AND TX SUGGESTING LOW WL BEGIN TO SHIFT MORE EAST THAN SOUTH LATER TNT. IR LOOP INDICATING ENHANCED CLOUD BAND ASSOCIATED WITH ISENT LIFT ACRS ERN NEB AND IA SHIFTING EWD WITH SNOW BEING REPTD ON WRN EDGE OF COLDER CLOUD TOPS OVR EXTREME WRN IA AND MO. RUC MODEL DEPICTING SFC LOW OVR NRN ARK BY 12Z THU...A TAD FURTHER NORTH THAN THE ETA/AVN. FIRST 12 HOURS OF THE 00Z ETA NOT SHOWING ANY SIG SHIFTS IN THE SFC OR 850 LOW...WHICH ARE FORECAST TO TRACK SOUTH OF IL PUTTING AREAS ALONG AND SOUTH OF I-72 IN LINE FOR THE HEAVIEST SNOWS WITH THIS SYSTEM. 18Z AVN EVEN SHOWING SOME NEGATIVE PVU EXTDG FROM N-CNTRL MO THRU S-CNTRL IL BY 12Z THU...SUGGESTING THE POTENTIAL FOR AT LEAST SOME SMALL SCALE BANDING OF THE PRECIP. THIS ALREADY EVIDENT OVR PARTS OF SE NEB...NE KS AND NW MO. DYNAMICS SHIFT OFF TO OUR EAST RATHER QUICKLY BY TOMORROW AFTERNOON WITH SNOWS ENDING FROM NW TO SE BY EVENING. OTHER THAN THE ABOVE MENTIONED MINOR TWEEKS TO PRECIP TIMING TONIGHT...REST OF FCST LOOKS FINE. .ILX...HEAVY SNOW WARNING TONIGHT THROUGH THURSDAY SOUTH OF I-72...ILZ040-047>057-061>063-066>068-071>073. SNOW ADVISORY TONIGHT THROUGH THURSDAY NORTH OF I-72...ILZ036-041>046. $$ SMITH il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1045 AM CST WED JAN 15 2003 WILL LOWER MAX TEMPS A CATEGORY NORTH CENTRAL. OTHERWISE...ONLY MINOR CHANGES TO WINDS ANTICIPATED AT THIS TIME. CURRENT PACKAGE APPEARS ON TRACK TODAY WITH INCREASING HIGH CLOUDS STREAMING IN FROM DEVELOPING SYSTEM OVER THE HIGH PLAINS. TEMPS SLOWLY REBOUNDING EXCEPT IN SOUTH WHERE MORE SUN HAS ALLOWED TEMPS TO CLIMB A BIT MORE QUICKLY. WILL LOWER HIGHS NORTH CENTRAL A CATEGORY TO BRING MORE IN LINE WITH CURRENT TRENDS. RUC AND CURRENT GRADIENT SUGGESTS THAT WINDS WILL BE MORE NORTHWEST THAN WEST THROUGH THE REMAINDER OF THE DAY. .ILX...WINTER STORM WATCH LATE WEDNESDAY NIGHT INTO THURSDAY SOUTH CENTRAL AND SOUTHEAST. ILZ040-047>057-061>063-066>068-071>073. $$ BARKER il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 933 PM CST WED JAN 15 2003 HAVE UPDATED TO DOWNGRADE WARNING TO ADVISORY AND LEAVE ORIGINAL ADVISORY IN PLACE. AIRMASS REMAINS VERY DRY AND SNOWFALL AMOUNTS LOWERED. ALSO HEAVIER BANDS PRODUCING 4-5 INCHES IN NE HAVE DIVED DIRECTLY SOUTH OUT OF CWA. RUC/ LTST MESOETA ARGREE ON KEEPING AMOUNTS LOWER. MAYBE ISOLD 4 OR 5 IN ADVISORY AREAS HWVR EXPECT 2-4 IN GENERAL. .DSM...WINTER WEATHER ADVISORY ALONG AND SW OF AN AUDUBON TO CORYDON LINE. WINTER WEATHER ADVISORY TONIGHT ALONG AND S OF A CARROLL TO JEFFERSON TO DES MOINES TO OTTUMWA LINE. MYEFORSTER ia AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 821 PM MST WED JAN 15 2003 WHAT SNOWFALL THERE WAS HAS ENDED ACROSS THE FORECAST AREA. UPPER LOW IS TO THE NORTHEAST OF THE AREA...AND WILL CONTINUE TO DIG SOUTHEAST. DRIER AIR...SUBSIDENCE...AND WINDY CONDITIONS HAVE MOVED INTO THE WESTERN PORTION OF THE AREA. WILL REMOVE ALL MENTION OF FLURRIES WITH WHATEVER SNOW STAYING TO THE EAST OF THE AREA. WILL HAVE SKIES PARTLY CLOUDY OR BECOMING PARTLY CLOUDY IN THE WEST. SATELLITE AND RELATIVE HUMIDITY PROGS WOULD SAY THAT CLOUDY TO MOSTLY CLOUDY SKIES WILL PEVAIL IN THE EAST...AND WILL GO WITH. LATEST RUC SAYS THAT STRONGER WINDS WILL NOT MOVE INTO THE EAST UNTIL AFTER 06Z...AND WILL WORD THAT WAY. LOW DEWPOINTS UPSTREAM WILL MOVE INTO THE WESTERN PORTION OF THE AREA. WINDS WILL KEEP TEMPS FROM DROPPING TOO MUCH...BUT WILL HAVE GOOD COLD AIR ADVECTION. WILL DROP TEMPS A LITTLE IN PORTIONS OF THE WEST. .GLD...NONE. BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 315 PM CST WED JAN 15 2003 DAYS 1-2... FORECAST CHALLENGE IS CHANCES FOR FREEZING DRIZZLE AND/OR SNOW THIS EVENING AND THEN WINDS OVERNIGHT INTO THURSDAY MORNING. SFC OBS AND LAMP SFC FIELDS SHOW THE SURFACE LOW PRESSURE SYSTEM DEEPENING OVER THE EXTREME WESTERN OK PANHANDLE THIS AFTERNOON WITH THE ARCTIC AIRMASS HANGING TOUGH OVER MOST OF SOUTHWEST KANSAS. EXTREME SOUTHWEST CORNER OF THE STATE WAS BREAKING OUT OF THE STRATUS AND TEMPERATURES HAD CLIMBED TO 60 DEG AT KEHA. TEMPS FALL OFF FAST TO THE NORTHEAST WITH AREAS AROUND AND NORTHEAST OF KGCK AND KDDC TO KP28 REMAINING AOB FREEZING. SAT LOOPS SHOW THAT THE H5 SHORTWAVE TROUGH WAS MOVING OUT INTO EASTERN COLORADO THIS AFTERNOON. SOME LIGHT FREEZING DRIZZLE HAD DEVELOPED OVER NORTHERN SECTIONS OF THE CWA THIS AFTERNOON AS WARM AIR ADV INCREASED AHEAD OF THE UPPER WAVE. AS THE AXIS OF THE UPPER WAVE MOVES OUT ACROSS WESTERN KANSAS EARLY THIS EVENING, THINK THAT FREEZING DRIZZLE WILL MIX WITH LIGHT SNOW FOR A SHORT TIME BEFORE MOVING EAST OF THE AREA BY MID EVENING. WILL NOT GO WITH ANY HEADLINES AT THIS TIME AS THE FREEZING PRECIP WILL BE PATCHY AND SHORT LIVED. SFC LOW HEADING TO THE SOUTHEAST THIS AFTERNOON AS THE UPPER SYSTEM IS NOW KICKING IT OUT. NORTHERLY WINDS WILL BE PICKING UP ALONG THE COLORADO BORDER LATE THIS AFTERNOON AND SPREADING EAST AS THE NIGHT PROGRESSES. RUC/MESOETA DEVELOPING 40-50 KT WINDS AT THE H85 LEVEL OVERNIGHT. COULD BE SUSTAINED WINDS REACHING ADVISORY CRITERIA EARLY THIS EVENING ALONG THE COLO BORDER BUT FEEL THAT CLEARING SKIES AND COLDER AIR MOVING INTO THE REGION AT THE SURFACE WILL KEEP THOSE WINDS FROM FULLY MIXING DOWN TO THE SURFACE. WILL INCREASE WINDS FROM CURRENT FORECAST INTO THE WINDY CATEGORY AND MENTION GUSTS TO 40 MPH. STRONG WINDS WILL CONTINUE INTO THURSDAY BUT SHOULD BE DIMINISHING SOMEWHAT BY AFTERNOON AS UPPER LEVEL WINDS AND SFC PRESSURE GRADIENT DECREASES. CURRENT TEMPERATURE FORECAST LOOKS PRETTY GOOD AND HAVE NOT DEVIATED TOO MUCH FROM IT. LOWS TONIGHT SHOULD DROP INTO THE 15 TO 20 DEGREE RANGE WITH HIGHS ON THURSDAY ONLY CLIMBING INTO THE 30 TO 35 DEGREE RANGE. SURFACE HIGH PRESSURE BUILDS DOWN INTO THE CENTRAL HIGH PLAINS THURSDAY NIGHT. WILL CONTINUE WITH LOWS DROPPING TO AROUND 10 DEGREES WHICH IS IN LINE WITH MAV GUIDANCE AND BELOW FWC/ETA. DAYS 3-7... MEDIUM RANGE MODELS WERE IN FAIRLY GOOD AGREEMENT FOR INITIALIZATION THROUGH DAYS 3-6. NORTHWEST FLOW WILL DOMINATE THE PLAINS THROUGH THE WEEKEND, WITH A WEAK VORT MAX MOVING THROUGH THE FLOW AND AWAY FROM THE PLAINS FRIDAY NIGHT. WINDS WILL SHIFT AROUND TO A MORE WESTERLY COMPONENT ON SATURDAY, SO ALONG WITH RISING HEIGHTS AND SUNNY SKIES, CONDITIONS LOOK GOOD FOR TEMPERATURES TO REACH THE CURRENT FORECAST OF MID TO UPPER 40S. SOUTHWESTERLY SURFACE WINDS PICK UP ON SUNDAY AS ANOTHER SHORTWAVE TROUGH MOVES THROUGH THE NORTHERN PLAINS AND UPPER MS VALLEY. TEMPERATURES SHOULD RISE UP WELL ABOVE AVERAGE AGAIN. A CUT OFF LOW IS EXPECTED TO BEGIN TO OPEN UP AND MOVE FROM BAJA CALIFORNIA INTO THE SOUTHERN PLAINS ON MONDAY. THERE IS SOME DIFFERENCES IN THE STRENGTH OF THE SYSTEM, WITH THE CANADIAN THE STRONGEST, THE ECMWF FASTER AND WEAKER, AND THE GFS IN THE MIDDLE. HOWEVER, THE SYSTEM HAS LIMITED MOISTURE AND IS A BIT TOO FAR SOUTH TO REALLY AFFECT SENSIBLE WEATHER HERE IN SOUTHWEST KS ANYWAY. MONDAY AND TUESDAY LOOK TO BE FAIRLY DRY AND QUIET WITH COOLING TEMPERATURES AS HEIGHTS START TO FALL. THINGS START TO GET INTERESTING ON DAY 7. THE GFS AGAIN TRIES TO PHASE TWO SHORTWAVE TROUGHS OFF OF NORTHWESTERN NORTH AMERICA AND BRING THE SYSTEM DOWN AS A LARGE SCALE TROUGH INTO THE NORTHERN ROCKIES AND INTERMOUNTAIN WEST, WHILE THE RIDGE RETROGRADES WESTWARD. WITH AN ASSOCIATED SURFACE LOW OVER UTAH AND A STRONG ARCTIC HIGH OVER WESTERN CANADA, THE SIGNS LOOK RIGHT FOR STRONG WINDS AND UPSLOPE SNOW OVER THE WESTERN HIGH PLAINS BY LATE WEDNESDAY. HOWEVER, LOOKING AT THE GFS ENSEMBLE SPAGHETTI PLOTS, THERE IS A LOT OF SPREAD WITH THIS SYSTEM, AND THE ENSEMBLE MEAN IS DISAGREEING WITH THE OPERATIONAL RUN. THE CANADIAN ENSEMBLE IS SIMILAR, WITH THE MEAN CONTINUING TO SHOW NORTHWESTERLY FLOW OVER THE PLAINS, WHILE ONLY ONE OR TWO ENSEMBLE MEMBERS SHOW A TROUGH DIGGING INTO THE WEST. A LOT OF UNCERTAINTY EXISTS, SO I WILL KEEP THE FORECAST DRY FOR NOW, BUT THE SYSTEM WILL HAVE TO BE WATCHED CLOSELY TO SEE HOW THINGS DEVELOP IN FUTURE RUNS. THANKS FOR THE COORD...PUB,GLD,ICT,AMA,OUN. PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE CONTAINED WITHIN THE DODGE CITY ZONE FORECAST. DDC 17 33 10 40 / 20 0 0 0 GCK 15 32 8 40 / 20 0 0 0 EHA 16 35 11 44 / 0 0 0 0 LBL 15 34 9 44 / 0 0 0 0 HYS 12 29 7 34 / 30 0 0 0 P28 19 30 9 39 / 0 0 0 0 .DDC...NONE. GERARD/RITTERLING ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1011 AM CST WED JAN 15 2003 ...UPDATED... MRNG RAOBS/MTRS/PIREPS/SATL SHOW TREND OF SATURATING THE LWR ATMOS IN THE 2-5K FT LYR JUST TO OUR SW, WITH PLENTY OF DRY MID LVL AIR BLO THE CIRRUS LVL CIGS. DEPENDING ON SFC TEMPS LATER THIS AFTN, THE MODEL SOUNDINGS STILL SUPPORT DRZL OR FRZG DRZL TWD 00Z ACRS THE SRN CWA, ASSUMMING MSTR WL BE SUFFICIENT WITH ONSET OF BETTER LIFT ACRS THE AREA. CURRENT MTRS SUGGEST NR SFC AIRMASS IS STILL VRY DRY WITH DWPTS IN THE 10 TO 15F RANGE, SO WE MAY NOT SEE MUCH OF ANYTHING BUT CLOUDS BFR 22Z. THEREFORE, PLAN TO PUSH BACK ADVSY UNTIL THIS EVENING. UPDATED GRIDS/ZONES/WSW OUT BY 17Z. KED .ICT...WINTER WEATHER ADVISORY FOR THIS EVENING THROUGH THURSDAY MORNING FOR KSZ052>053...KSZ069>072...KSZ093>096...KSZ098>100. ------------------------------------------------- PREVIOUS DISCUSSION... 320 AM CST WED JAN 15 2003 LOTS OF CONCERNS THIS MORNING WITH A MIXED BAG OF WINTER PRECIP SLATED TO MOVE INTO CEN/SERN KS LATER TODAY AND TNGT. POTENT S/WV COMING ACROSS THE ROCKIES ATTM...WITH SFC LOW STARTING TO THE DVLP ON THE LEE SIDE OF THE ROCKIES IN RESPONSE TO THIS. DRY LOW LAYERS IN PLACE ATTM...BUT THAT WILL CHANGE AS THE DAY PROGRESSES. LOW CLOUDS/STRATUS ALONG THE RED RIVER OF OK/TX IS ALREADY STARTING TO CREEP NORTH TOWARDS KS. RUC/ETA SHOWS LOW LEVEL MOISTURE MOVING BACK INTO SRN KS AFTER 18Z...SATURATING THE 850-750H LAYER ENOUGH FOR A ZL CHC AS SFC TEMPS MAY BE CLOSE TO FREEZING THIS AFTN ACROSS SRN SECTIONS OF KS. PREVIOUS SHIFTS INTRODUCED THIS ZL CHC AS LAYER ALOFT DOESNT SATURATE ENOUGH FOR ICE CRYSTAL (AND SNOW) FORMATON...BUT ENOUGH FOR DRIZZLE WITH FREEZING TEMPS. SO WILL CONTINUE THIS TREND FOR THE AFTN AND EVE. AM A LITTLE WORRIED ABOUT ICT AREA TURNING INTO THE A SKATING RINK...WE BRIEF NEXT SHIFT ON THIS. NEXT CONCERN IS SNOW CHC AS MAIN SFC LOW MAKES ITS WAY ALONG THE RED RIVER THIS EVE. ISENTROPIC LIFT BEGINS TO SATURATE THE LAYER NE OF CEN KS...SO DO NOT EXPECT MUCH ISENTROPIC LIFT SNOWS ACROSS SRN KS OR SERN KS...SO MAIN SNOW CHC WILL PROBABLY BE WITH THE FRONTOGENIC FORCING AND OMEGA ASSOC WITH THE MAIN S/WV AND ASSOC COLD CORE TNGT. TRENDS HAVE BEEN TO TAKE MAIN HVY SNOW TRACK FURTHER NE OF THE AREA...BUT ENOUGH MOISTURE AVAILABLE FOR AT LEAST A LARGE SWATH OF 2-5 INCH ACCUMULATING SNOWS LATE TNGT...WITH HEAVIEST SNOWS IN SERN KS (ALONG A MARION TO CHANUTE AXIS) ..WITH LESSER AMOUNTS WEST AND SOUTHWEST OF THIS AXIS. SO WILL HOIST AN ADVISORY FOR MOST OF THE COUNTIES THAT WERE PREVIOUSLY IN THE WATCH FOR THIS AFTN AND TNGT. MAY LEAVE OUT A FEW COUNTIES IN CEN KS (SALINE/MCPHERSON) ...WHERE 1 TO 2 INCH AMOUNTS WILL BE FOUND. LAST CONCERN WILL WINDS AS LOW PRESSURE DEEPENS. WILL KEEP ADVISORY GOING INTO THU MORNING...AS ANY SNOW THAT FALLS WILL BE BLOWN AROUND CONSIDERABLY. ARCTIC HIGH PRESS SLIDE SOUTH INTO THE AREA FOR THU NIGHT AND FRI WITH GOING TEMPS LOOKING FINE. NW FLOW ALOFT AND SFC HIGH PRESSURE MOVING SOUTH INTO THE GULF WILL KEEP SRN KS DRY AND CHILLY INTO THE WEEKEND. NW FLOW KEEPS SENDING IMPULSE AFTER IMPULSE SE ACROSS MO/IA AND IL SAT AND SUN NIGHT BUT THESE WILL STAY NE OF KS. WILL CONTINUE A SLIGHT WARMING TREND INTO SUNDAY...AS EACH IMPULSE BRINGS SOME WEAK WAA TO KS. ANOTHER COLD POLAR AIRMASS ARRIVES TUES INTO WED...WITH LATEST GFS SUGGESTING SOME OF THE COLDEST TEMPS OF THE SEASON INTO KS. THANKS FOR THE COORD...TOP/SGF/EAX/TUL. FCSTID = 22 / KETCHAM ICT 32 18 25 10 / 30 50 30 10 HUT 31 17 25 9 / 30 50 20 10 EWK 31 17 25 9 / 30 50 30 10 EQA 32 18 26 10 / 30 60 30 10 WLD 32 20 27 11 / 30 60 40 10 RSL 29 15 23 6 / 30 60 20 10 GBD 31 15 24 6 / 30 50 20 10 SLN 29 16 24 7 / 30 70 20 10 MPR 31 17 25 9 / 30 50 30 10 CFV 32 23 28 12 / 30 70 60 10 CNU 32 23 27 12 / 30 80 60 10 K88 31 22 27 11 / 30 80 60 10 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1035 PM EST WED JAN 15 2003 MAIN FCST CONCERNS OVERNIGHT INCLUDE LINGERING LIGHT LES EAST ALONG WITH CLOUDS/TEMPS. WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPR LVL FLOW THROUGH THE WRN LAKES WITH NEXT SIGNIFICANT SHRTWV POISED WELL UPSTREAM OVER NW ONTARIO. IR LOOP SHOWED HIGH CLOUDS INTO NRN WI ON NORTHERN FRINGE OF CENTRAL PLAINS STORM SYSTEM. AT THE SFC...WRLY LOW LVL WINDS CONTINUED WITH RDG AXIS INTO SW WI. 00Z CWPL/KINL/KGRB SNDGS INDICATED VERY DRY PRFL WITH H8 TEMPS NEAR -11C...PWAT AOB 0.10 INCH...AND INVERSION HGT NEAR 930 MB WITH T-TD BLO THE INVERSION NEAR 10C. DRY AIR HAS ALLOWED SKIES TO CLEAR ACRS WEST UPR MI DESPITE CONTINUE WRLY FLOW. LONGER FETCH INTO THE E WITH WNW WIND STILL PRODUCED A FEW CLOUDS AND AND LIGHT LES WITH KERY REPORTING 5SM -SHSN. 00Z ETA/RUC FCST WINDS CONTINUE TO BACK PUSHING MOST REMAINING LES OFFSHORE FROM THE NE PORTION OF THE CWA. 500-400 MB RH FCST SUGGEST MOST OF THE THICKER CI WILL REMAIN TO THE SOUTH. WHILE UPSTREAM DRY AIR WILL BE UNFAVORABLE FOR LAKE CLOUDS OR FLURRIES OVER THE WEST...CANNOT RULE OUT SOME PATCHY CLOUDS...ESPECIALLY IN UPSLOPE LOCATIONS. WIND WILL HAMPER RADIATIONAL COOLING AS GRADIENT REMAINS TIGHT ENOUGH TO KEEP WINDS FROM DECOUPLING WITH THE EXCEPTION OF SOME SHELTERED LOCATIONS OVER THE INTERIOR WEST. LACK OF SNOW COVER OVER THE SOUTH ALSO IS NOT FAVORABLE. SO...WL ADJUST LOW PORTION OF THE RANGE UP SLIGHTLY. .MQT...HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 330 PM EST WED JAN 15 2003 12Z RAOBS/LATEST WV LOOP AND RUC ANLSYS SHOW FULL LATITUDE TROF OVR ERN NAMERICA DOWNWND OF HI AMPLITUDE RDG OVR THE W WITH NW FLOW ALF ALLOWING ARCTIC AIR TO SPILL S INTO THE UPR LKS. LES ONGOING OVR WRN AND ERN CWA IN LLVL NWLY FLOW BTWN HI PRES RDG IN THE PLAINS AND LO PRES OVR SE CAN...BUT DRY AIR UPSTREAM (DWPTS IN -10 TO -20F RANGE OVR WRN ONTARIO/NRN MN) AND STABLE SDNGS AT YPL/INL (INVRN HGT H9 OR LWR) LIMITING ACTIVITY DESPITE INVRN HGT ARND H8 AS DEPICTED ON 12Z APX SDNG. ACTIVITY ESPECIALLY WEAK OVR THE WRN ZNS...WHERE FETCH IS MUCH SHORTER. BACK EDGE OF LK CLD IS NO MORE THAN 40M OFFSHORE... WITH BACK EDGE TENDING TO MOVE CLOSER TO CWA SHORELINE. SHRTWV EMBEDDED WITHIN NWLY FLOW AND MOVG THRU NE ONTARIO HELPING TO MAINTAIN A BIT OF A LK INDUCED TROF OVR ERN LK SUP...WHERE NMRS WND PARALLEL LES BANDS ARE BETTER ORGANIZED IN LONGER FETCH. BUT CLOSEST BAND TO RADAR SITE FM JUST OFFSHORE AT BIG BAY TO WRN ALGER COUNTY HAS JUST A FEW REFLECTIVITY RETURNS AOA 20DBZ. SVRL OTHR SHRTWVS OF NOTE...ONE MOVG INTO NRN HUDSON BAY. ANOTHER SHRTWV APRNT OVR THE NW TERRITORIES MOVG OVR TOP OF BIG WRN RDG. MAIN FCST CONCERNS TNGT ARE LES TRENDS/TEMPS...THEN ATTENTION TURNS TO TIMING/IMPACT OF UPSTREAM SHRTWVS DROPPING INTO NW GRT LKS IN PERSISTENT NWLY FLOW ALF. FOR TNGT...12Z MODELS IN GOOD AGREEMENT SHOWING HGT RISES/DNVA BEHIND ONTARIO SHRTWV DOMINATING WITH UPR RDGING APRNT OVR CWA BY 12Z. XPCT LWRG INVRN HGT PER 12Z INL/YPL SDNGS/PASSAGE OF H85 THERMAL TROF EARLY THIS EVNG TO END LES EARLY OVR THE W AND BY LATE EVNG OVR THE E. LLVL FLOW PROGGED TO REMAIN WNW...SO SKIES WL REMAIN MCLR INLAND TO MOCLDY OVR THE ERN ZNS DOWNWND OF THE LK. CLR SKIES AND LO DWPTS UPSTREAM SUG MIN TEMPS WL FALL SHARPLY TNGT...BUT ETA SHOWS PRES GRADIENT REMAINING QUITE SHARP WITH MODEL INDICATING 1-2K FT WNDS STAYING 20 TO 30 KT ALL NGT. GFS IS WEAKER WITH PRES GRADIENT BUT TRIES TO RAISE THE PRES TOO MUCH OVR ERN LK SUP. CONSIDERING RELATIVELY WARM WATER AND ETA'S BETTER HANDLING OF LK INFLUENCES... PREFER THE ETA/NGM IDEA OF LWR PRES OVR ERN LK SUP/SHARPER GRADIENT OVR CWA. WL GO FOR A WIDE RANGE OF LO TEMPS TNGT TO REFLECT POTENTIAL FOR A FEW INLAND LOCATIONS TO DECOUPLE. LACK OF SN COVER ACRS THE SCNTRL MAY LIMIT MIN TEMP DROPOFF THERE. FOCUS ON THU/THU NGT IS TIMING AND IMPACT OF SHRWV NOW MOVG INTO NRN HUDSON BAY. 12Z MODELS SHOW SHARP COLD FNT MOVG N-S ACRS CWA DURG THE DAY. SINCE THERE IS A LACK OF WAD/ISENTROPIC LIFT AHD OF SHRTWV...XPCT ALL PCPN TO FALL AT TIME OF AND POST FROPA. THERE MAY BE A BRIEF BURST OF SN WITH FROPA UNDER A NARROW BAND OF H85-5 QVECTOR CNVGC/DPVA...BUT ACTIVITY SHUD BCM PURE LES QUICKLY. MODELS DO SHOW DISCREPANCY ON HOW FAR WNDS VEER IN THE AFTN BEHIND FROPA... WITH ETA MAINTAINING MORE OF A NW FLOW VS THE MORE NLY FLOW DEPICTED ON THE GFS. LLVL WND DIRECTION IS IMPORTANT BECAUSE OF LES IMPACT. SINCE A H5 VORT LOBE ASSOCIATED WITH THE SHRTWV DIGS SHARPLY INTO WI AND GEOSTROPHIC WND IS FCST NNE...PREFER THE MORE SHARPLY VEERED GFS. MODELS DEPICT PROGRESSIVE H85 THERMAL TROF -20C TO -22C MOVG THRU LK SUP BY 00Z FRI AND THRU CWA BY 06Z FRI WITH 6 HR PD OF LWR H85 TEMP/HIER INVRN. ETA FCST SDNGS SHOW INVRN HGT RISING TO ABOUT 5K FT IN LONGEST/MOST WELL MIXED TRAJECTORY DOWNSTREAM OF LK SUP. LES CHART SUGS UP TO 4"/6HRS DURG MOST FVRBL WINDOW OF LES WHEN WNDS NOT SHIFTING TOO MUCH. XPCT SN TO FALL UP TO 12 HRS AT A FEW PLACES FM THU AFTN INTO THU NGT...BUT SHIFTING WNDS WITH TIME/HGT AND DRY AIR ADVCTN WL LIMIT SN ACCUM BEYOND PRIME WINDOW. A FEW PLACES WL LIKELY PICK UP 6" DURG THIS EVENT...AND COMBINATION OF WNDS UP TO 30 MPH WL CAUSE AREAS BLSN AND LIKELY NEED FOR LES SN/BLSN ADVY. WL HOLD OFF ON ADVY ATTM SINCE EVENT IS LATE 2ND PD AND THERE IS STILL SOME UNCERTAINTY AS TO WND DIRECTION BEHIND FROPA. BASED ON PREFERENCE FOR GFS LLVL WNDS...SUSPECT ADVY CONDITIONS WL BE MOST LIKELY ALGER/ MQT AND ONT/GOGEBIC (PREFERRED FOR 340 TO 360 WND). FOLLOWING PASSAGE OF H85 THERMAL TROF LATE THU NGT...FCST SDNGS SHOW INVRN HGT FALLING QUICKLY. SO LES WL DIMINISH AFTR 06Z AS WNDS SHIFT MORE WNW. MAX TEMPS WL REACH WELL INTO THE 20S ACRS THE SCNTRL AHD OF THE FNT WITH DOWNSLOPING WLY FLOW...BUT READINGS WL FALL OFF SHARPLY DURG THE AFTN OVR THE NRN TIER AND THEN ACRS THE ENTIRE CWA THU NGT. MODELS SHOW UPR RDGING/INCRSG LLVL ACYC FLOW MOVG OVR CWA IN WAKE OF THU SHRTWV...SO XPCT LINGERING MRNG LES TO DIMINISH. AS THE DRY LLVL FLOW BCMS SW...XPCT ANY MRNG CLD NR THE LK TO GIVE WAY TO INCRSG SUNSHINE. SCNTRL ZNS SHUD ENJOY MOSUNNY DAY. GFS/ETA SHOW H85 TEMPS RISING TO -7 TO -8C DURG THE AFTN. ETA FCST SDNGS/MIXING TO H925 ENHANCED BY STEADY WSW FLOW SUPPORTS HIER ETA/GFS MOS FCST MAX. 00Z/06Z/12Z MODEL RUNS WITH GOOD AGREEMENT FM 00Z GFS ENSEMBLE ALL INDICATE SHRTWV OVR NW TERRITORIES IMPACTING CWA ON SAT. SOLNS SHOW CLIPPER TYPE SFC LO TRACKING ACRS NRN CWA/LK SUP WITH CYC NLY FLOW ON BACK SIDE OF SFC LO. WL BUMP POPS UP TO LIKELY ALL ZNS ON SAT EVEN SCNTRL DUE TO FAIRLY IMPRESSIVE DYNAMICS FCST. BUT BEST SN APPEARS LIKELY NR LK SUP CLOSER TO SFC LO TRACK AND DUE TO POTENTIAL FOR LK ENHANCMENT. 00Z EXTENDED MODELS/GFS ENSEMBLE ALL IN GOOD AGREEMENT POINTING TOWARD ARCTIC INVASION EARLY NXT WEEK AS POLAR VORTEX/H85 TEMPS BLO -30C/H100-5 THKNS WELL UNDER 500DM MOVE INTO ONTARIO. ANOTHER CLIPPER TYPE SYS LATE SUN/MON APPEARS TO INTRODUCE THIS BRUTALLY COLD AIRMASS INTO THE NW LKS. HAVE OPTED FOR HI CHC/LIKELY POPS NR LK SUP FOR SUN INTO TUE FOR CLIPPER IMPACTS AND LES WITH LO CHC POPS AWAY FM THE LK. WL GO BLO GFS MOS GUIDANCE FOR TEMPS IN LATER PDS WITH GFS/ECMWF FCSTG H85 TEMP OVR CWA FALLING TO AT LEAST -30C BY TUE. COORDINATED WITH APX. .MQT...HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1053 AM EST WED JAN 15 2003 MAIN FORECAST ISSUES FOR TODAY ARE LES AMTS AND TEMPS. WK UPR SHORTWAVE MOVING THRU THE NRN GREAT LAKES ATTM. LAKE-INDUCED SFC TROF CONTINUES W/ RIDGE AXIS STILL IN UPR MISSISSIPPI VALLEY. AS A RESULT SHSN CONTINUE BOTH IN W AND E PARTS OF THE CWA. TEMPS REMAIN IN SINGLE DIGITS TO NR 10F...WHICH COMBINED W/ WIND SPEEDS IN EXCESS OF 10 MPH ARE PRODUCING WIND CHILLS IN SINGLE DIGITS BELOW ZERO. KMQT RADAR SHOWS PERSISTENT THOUGH NOT TOO INTENSE BANDS INTO ALGER/LUCE CTYS...BUT NO ECHOES IN WEST (INDICATIVE OF LOW TOPS). VIS IMAGERY AND RECENT OBS SHOW SHSN CONTINUING IN W DESPITE LWRG INVERSION HGTS. SAT IMAGERY ALSO SHOWING DRY AIR MAKING MORE SERIOUS PROGRESS INTO NW QUARTER OF LAKE...CONSISTENT W/ UPSTREAM SFC DEWPTS IN NEGATIVE TEENS AND 12Z RAOBS WHICH ARE QUITE DRY. AREA OF Q-VECTOR CONVERGENCE ASSOCIATED W/ AFOREMENTIONED SHORTWAVE ADDING SOME LIFT IN E THIS MORNING...BUT THAT LOOKS TO EXIT REGION BY EARLY THIS AFTN...PER BOTH THE MESOETA AND RUC. SO...AM EXPECTING SHSN TO DIMINISH THIS AFTN AS INV HGTS LOWER FROM NR 5KFT AT MIDDAY TO 3KFT LATE...PER ETA SOUNDINGS AT KERY. AS LLVL FLOW BEGINS TO BACK LATER TODAY...LLVL CONVERGENCE WILL DISSIPATE AS WELL. DESPITE ALL OF THIS...KMQT RADAR AND SPOTTER REPORTS INDICATE A LITTLE MORE ACCUMULATION THAT PREVIOUSLY THOUGHT (IN ERN ZONES). W/ 1-3 INCHES ALREADY FALLEN THIS MORNING...ANOTHER INCH OR TWO CERTAINLY NOT OUT OF THE QUESTION YET THIS AFTN BEFORE THINGS WIND DOWN. OUT WEST... WILL KEEP W/ SCT SHSN WORDING AND SOME LOCAL INCH ACCUMULATION. SHSN WILL CONTINUE AS THEY BECOME INCREASINGLY SCATTERED. AS FAR AS TEMPS GO...DESPITE CHILLY TEMPS AT 15Z...SHOULD SEE SOME WARMING THIS AFTN...ESPECIALLY IN WEST HALF. RUC/MESOETA H8 TEMPS RISE TO -12C BY 21Z (FROM NR -16 THIS MORNING). THIS PLUS SOME SUN SHOULD BE ENOUGH TO GET US INTO THE MID OR UPR TEENS. LOCATIONS IN NERN ZONES MAY NOT GET THERE DUE TO PERSISTENT CLD COVER OFF OF THE LAKE. HIGH TEMPS FCST LOOKS GENERALLY ON TRACK. WILL SEND UPDATE SHORTLY TO ACCOUNT FOR AFTN SNOW ACCUMS...AND TO MASSAGE TEMPS A LITTLE. JKL .MQT...HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 935 PM CST WED JAN 15 2003 ...WINTER STORM CONTINUES TO ORGANIZE... ...NO CHANGES TO THE WARNINGS OR ADVISORIES AT THIS TIME... LATEST WATER VAPOR AND RUC MODEL DATA SHOWS A POTENT SHORTWAVE CONTINUES TO CONGEAL OVER THE SOUTHERN PLAINS. APPEARS THE VORTICITY MAXIMUM OVER THE OKLAHOMA/TEXAS PANHANDLES WILL BECOME THE DOMINANT FEATURE. A BAND OF SNOW FROM NEBRASKA TO NORTHWEST MISSOURI APPEARS TO BE IN AREA OF BEST LOW TO MID LEVEL THETA-E ADVECTION AND FRONTOGENESIS. LOW LEVELS HAVE BEEN SLOW TO SATURATE TO THIS POINT. ANOTHER AREA OF PRECIPITATION WAS BEGINNING TO BREAK OUT NORTH TO SOUTH ACROSS CENTRAL KANSAS AND OKLAHOMA. THIS AREA WAS DEVELOPING IN AN AREA OF INCREASING POSITIVE VORTICITY ADVECTION AHEAD OF THE POTENT SHORTWAVE. I WOULD EXPECT THIS DEVELOPING AREA OF PRECIPITATION TO BE THE PRIMARY EVENT THAT BRINGS SNOW TO THE AREA LATER TONIGHT. MODERATE TO STRONG Q-VECTOR CONVERGENCE WILL SPREAD OVER THE AREA AFTER MIDNIGHT. LATEST ETA BACKED OFF ON PRECIPITATION TOTALS AND SNOW ACCUMULATIONS BUT I AM A LITTLE LEARY OF THIS. SPECIFIC HUMIDITY VALUES STILL IN THE 2 TO 3 RANGE SO 2 TO 5 INCHES STILL LOOK REASONABLE OVER MUCH OF THE AREA. ACCUMULATIONS OVER 6 INCHES MAY BE DIFFICULT GIVEN THE SPEED OF THE SYSTEM AND INITIAL DRY LOW LEVELS. STRONG NORTHWEST WINDS AND RESULTING BLOWING SNOW STILL LOOK LIKELY THURSDAY AS A SURFACE LOW TRACKS ACROSS ARKANSAS. HOWEVER I WILL NOT MAKE ANY CHANGES TO THE CURRENT ADVISORIES OR WARNINGS. $$ .SGF... MO...WINTER STORM WARNING FOR TONIGHT AND THURSDAY...ALONG AND NORTH OF A LINE FROM OSCEOLA TO SALEM...MOZ055>058-067>071-083. WINTER WEATHER ADVISORY FOR ALL REMAINING COUNTIES... MOZ066-077>082-088>098-101>106. KS...WINTER WEATHER ADVISORY FOR TONIGHT AND THURSDAY KSZ073-097-101. FOSTER mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 930 PM CST WED JAN 15 2003 ...UPDATED... BROAD SNOW BAND HAD SET UP IN A WEST TO EAST ORIENTATION OVER THE NORTHERN HALF OF THE FORECAST AREA AROUND 00Z. LATEST REGIONAL RADAR LOOPS INDICATE THIS BAND MOVING SOUTH AND SHRINKING SOMEWHAT IN SIZE OVER SERN NEB AND EXTREME SWRN IA. ESTIMATED SNOWFALL AMOUNTS THROUGH 8PM FROM AROUND THE AREA ARE 4-5" IN THE NORTHERN FORECAST AREA. MORE SPECIFICALLY...KNOX...WAYNE...PLATTE...AND HARRISON COUNTIES ALL ESTIMATED 4-5". FURTHER TO THE SOUTH WHERE THE LOW LEVEL DRY AIR STAYED LONGER...ESTIMATES ARE IN THE 2" RANGE. 00Z UPPER AIR ANALYSIS SHOWED CLOSED MID LEVEL LOW OVR CNTRL NEB WITH 850 MB LOW CENTERED OVR SOUTH CENTRAL KS. IMPRESSIVE 150 METER HEIGHT FALLS WHERE NOTED AT 500 MB OVR SWRN KS. RUC MODEL AND INCOMING 00Z MODELS CONTINUE TO SHOW ONGOING STRONG VERTICAL MOTION IN THE LOW AND MID LEVELS. EXPECT TO SEE A CONTINUATION OF THE LIGHT TO MODERATE SNOWFALL ACROSS MUCH OF THE AREA AT LEAST THROUGH MIDNIGHT. INCREASING NORTH WINDS ARE OF A CONCERN AFTER THAT...WL KEEP WARNING AREA AS IS. GRIFFIS .OMA...WINTER STORM WARNING FOR TONIGHT ALONG AND NORTHEAST OF A LINE FROM SEWARD TO PAWNEE CITY. WINTER WEATHER ADVISORY TONIGHT SOUTHWEST OF THIS LINE. --------------------------------------------------------------- PREVIOUS DISCUSSION... 321 PM CST WED JAN 15 2003 FORECAST CHALLENGES ARE HOW MUCH SNOW WILL FALL AND THEN TEMPERATURES. SYNOPSIS-- BANDED SNOW IS INCREASING ON THE RADAR ALONG AND NORTH OF 41.5 LATITUDE. MID LEVEL FORCING WILL BE MOVING SE DURING THE EVENING HOURS. DRY AIR LAYER PERSISTS NEAR SURFACE EXCEPT IN AREAS WITH BEST SNOW. BEST FORCING REMAINS AT MID LEVELS. SHORT TERM FORECAST-- THE BIG QUESTION IS HOW MUCH ACCUMULATION. ETA REMAINS GENEROUS WITH QPF. IF TAKEN AT FACE VALUE...THIS WOULD TRANSLATE TO 6-10 INCHES GIVEN A RATIO OF 12 OR 15 TO 1. HOWEVER...DRY AIR INFLOW AT SFC IS A MAJOR FACTOR...AND WILL SIMPLY EVAPORATE SEVERAL INCHES. PREVIOUS FORECAST GENERALLY LOOKS GOOD...AT LEAST FOR NOW. LATER PERIODS--SNOW SHOULD TAPER OFF QUICKLY TOWARD MORNING...SO CURRENT DURATION OF WARNING LOOKS GOOD. THE BIG QUESTION IS WHETHER THE WIND WILL PICK UP ENOUGH THU MORNING TO CAUSE BLOWING PROBLEMS. BEST PRES GRADIENT AND 850 MB WINDS REMAIN TO OUR WEST. EXPECT TO SEE SOME DRIFTING...BUT NOT ENOUGH WIND FOR A LOT OF BLOWING. TEMPERATURES IN LATER PERIODS SHOULD BE HELD DOWN QUITE A BIT BY SNOW COVER. EXPECT ANY NEARLY CLEAR NIGHT WITH LIGHT WINDS TO PRODUCE SUBZERO TEMPERATURES. HOWEVER...THERE WILL BE A RAPID SERIES OF CLIPPERS...MAKING TIMING OF WINDS AND OVERALL TEMPERATURE TRENDS FROM ONE DAY TO THE NEXT SOMEWHAT DIFFICULT. THU NIGHT INTO FRI WILL OBVIOUSLY BE QUITE COLD. FIRST CLIPPER MAY PRODUCE LIGHT SNOW FRIDAY EVENING...WITH CLOUDS IN ADVIANCE OF SYSTEM INHIBITING WARMING. MIXING SHOULD KEEP TEMPS WARMER FRI NIGHT...8 TO 15 ABOVE. BY SAT ETA AND GFS ALREADY BEGINNING TO PART WAYS...WITH ETA COLD AND GFS FASTER WITH WARM ADVN. STUCK CLOSE TO COLDER SOLUTION FOR NOW. GFS DEPICTS A ANOTHER FAIRLY COLD DAY SUN...WITH A STRONGER CLIPPER THREATENING THE AREA SUN NIGHT. BY THEN...TIMING AND TRACK ARE BOTH QUITE UNCERTAIN...SO OPTED FOR LOW POPS. KEPT THE REST OF THE FORECAST DRY...ALTHOUGH YET ANOTHER CLIPPER WOULD CERTAINLY BE POSSIBLE. AGREE WITH HPC THAT A SOUTHERN SYSTEM IS LESS LIKELY TO AFFECT US THE MIDDLE OF NEXT WEEK...BUT WE WILL PROBABLY GET ANOTHER SLUG OF ARCTIC AIR MON OR TUE TO LAST INTO MIDWEEK. POLLACK ne SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 330 PM CST WED JAN 15 2003 CORRECTED FOR ADVISORY AREA BELOW ...UPDATED FOR EXPANDED ADVISORY AREA... REPORTS OF FZDZ CONT TO COME IN OVR THE WRN CWA. SN ALREADY UNDR WAY OVR THE NRN CWA WHILE DRY AIR LLVL CONTS TO RESIST PCPN OVR THE ERN CNTIES. WL KP OVRNGT SN AMOUNTS RATHER MODEST...HOWEVER REPORTS OF ICE ON THE OVRPASSES HAVE PROMPTED AN EXPANSION OF THE WINTER WX ADVISORY FOR TNGT. THIN COAT OF ICE WITH ONE TO THREE INCHES ON TOP COULD CERTAINLY POSE SOME TRAVEL PROBLEMS. .GID...WINTER WEATHER ADVISORY FOR ALL BUT SWRN CWA. KSZ005...183...017... 141 AND NEZ082...083 ARE EXCLUDED. 09 ...ORIGINAL BLO... RADAR RTNS AND SFC OBS IND -SN THRU THIS MRNG OVR NRN NEB AREAS UNDR MID LVL BAROCLINIC ZONE...BEST ANALYZED ON THE 700 MB MAPS AND PRETTY MUCH WHERE PROGGD. HOWEVER...VERY DRY AIR IN THE LLVLS HAS LTD PCPN UNDR THE CONTINUOUS ISENTROPIC LIFT OVR CNTRL AND ERN NEB...WITH DPS RMNG STEADY OR FALLING AT SOME LOCATIONS UNDR COOLING TOPS. THIS AFTN...88 RTNS EXPANDING/CIGS FALLING/WRN CWA DPS RISING AS LLVLS OVR THOSE ZONES SATURATE IMMEDIATELY IN ADVN OF 700 MB TROF AXIS AS IND ON THE PROFILERS. LK AT 850 MB PROFILERS IND 30 TO 40KTS ACRS WRN KS...POSSIBLY TAPPING NR ZERO C DP POOL ANALYZED OVR SWRN KS THIS MRNG. IR/WV PICS IND WARMING TOPS/DRIER AIR ADVCTG INTO THE SYS...WITH SOME REPORTS OF FZDZ OVR THE WRN ZONES. WL WATCH TREND BUT AT MOMENT...SCENARIO AS FORECASTED OVR THE PAST COUPLE OF DAYS CONTS TO LK OK DESPITE THE WEAK START. ON THE 12Z ISENTROPIC CHARTS DOWNGLIDE DOMINATED FAIRLY QUICK TNGT...HOWEVER OF INTEREST IS AMOUNT OF 2ND PD MDL QPF DVLPD UNDR MID LVL DEFORMATION ZONE/UPR JET. STILL WRESTLING WITH THESE FAVORABLE DYNAMICS VS RATHER BLEAK MSTR PICTURE. COLD AIR WITH THE LOW WL HELP WITH A SATURATED PROFILE...BUT POST 00Z DRY ADVCTN IS STILL A QN AS PER ETA PROG OF SPEC HUMIDITIES. 18Z META/RUC IND A SLGTLY WWD TRACK OF THE 700 MB LOW TNGT WHICH IS A CONCERN GIVEN PROLONGED ISENTROPIC LIFT/WWD PLACEMENT OF QPF AXIS WHICH WOULD RESULT. BOTTOM LINE IS THAT WE WILL STAY WITH THE 3 TO 5 INCHES IN THE NERN CNTIES DESPITE NO DAY ACCUMULATION. SN TOTALS OVR THE WRN ZONES WL BE KEPT LGT. BIT OF A HEDGE MAY BE NEEDED FOR CNTRL SWATH OF CNTIES BUT THINK ADVISORY OUTLINE AS IS SHOULD SUFFICE SINCE GIVEN STEADY CIGS/DPS AT GRI/HSI...WHICH WOULD BE WRN ADVSRY BDR. SN GRADIENT WL PROBABLY END UP BEING FAIRLY TIGHT WITH THIS SITUATION. OTHERWISE...COLD THE REST OF THE WEEK WITH WARMING THROUGH THE WEEKEND. NRN PLNS/UPR MS VALLEY CLIPPER CURRENTLY PROGGED TO DRAG MORE WARM AIR OFF THE HIGH PLNS THAT REINFORCE COLD...SO WL BUMP SAT TEMPS UP AGAIN. DAYS 6...7 AND BEYOND LKG INTERESTING WITH MAGNITUDE OF COLD AIR GFS PROGGED OVR THE CONUS. WL CONT TO TREND TEMPS DOWN IN THOSE TIME FRAMES...BUT NOT AS DRAMATIC AS FMR NMBRS JUST YET. .GID...WINTER WEATHER ADVISORY CONTINUES TONIGHT FOR VALLEY... SHERMAN...GREELEY...HOWARD...NANCE...MERRICK... HAMILTON...POLK ...YORK... AND FILLMORE COUNTIES. 9 ne SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 248 PM CST WED JAN 15 2003 RADAR RTNS AND SFC OBS IND -SN THRU THIS MRNG OVR NRN NEB AREAS UNDR MID LVL BAROCLINIC ZONE...BEST ANALYZED ON THE 700 MB MAPS AND PRETTY MUCH WHERE PROGGD. HOWEVER...VERY DRY AIR IN THE LLVLS HAS LTD PCPN UNDR THE CONTINUOUS ISENTROPIC LIFT OVR CNTRL AND ERN NEB...WITH DPS RMNG STEADY OR FALLING AT SOME LOCATIONS UNDR COOLING TOPS. THIS AFTN...88 RTNS EXPANDING/CIGS FALLING/WRN CWA DPS RISING AS LLVLS OVR THOSE ZONES SATURATE IMMEDIATELY IN ADVN OF 700 MB TROF AXIS AS IND ON THE PROFILERS. LK AT 850 MB PROFILERS IND 30 TO 40KTS ACRS WRN KS...POSSIBLY TAPPING NR ZERO C DP POOL ANALYZED OVR SWRN KS THIS MRNG. IR/WV PICS IND WARMING TOPS/DRIER AIR ADVCTG INTO THE SYS...WITH SOME REPORTS OF FZDZ OVR THE WRN ZONES. WL WATCH TREND BUT AT MOMENT...SCENARIO AS FORECASTED OVR THE PAST COUPLE OF DAYS CONTS TO LK OK DESPITE THE WEAK START. ON THE 12Z ISENTROPIC CHARTS DOWNGLIDE DOMINATED FAIRLY QUICK TNGT...HOWEVER OF INTEREST IS AMOUNT OF 2ND PD MDL QPF DVLPD UNDR MID LVL DEFORMATION ZONE/UPR JET. STILL WRESTLING WITH THESE FAVORABLE DYNAMICS VS RATHER BLEAK MSTR PICTURE. COLD AIR WITH THE LOW WL HELP WITH A SATURATED PROFILE...BUT POST 00Z DRY ADVCTN IS STILL A QN AS PER ETA PROG OF SPEC HUMIDITIES. 18Z META/RUC IND A SLGTLY WWD TRACK OF THE 700 MB LOW TNGT WHICH IS A CONCERN GIVEN PROLONGED ISENTROPIC LIFT/WWD PLACEMENT OF QPF AXIS WHICH WOULD RESULT. BOTTOM LINE IS THAT WE WILL STAY WITH THE 3 TO 5 INCHES IN THE NERN CNTIES DESPITE NO DAY ACCUMULATION. SN TOTALS OVR THE WRN ZONES WL BE KEPT LGT. BIT OF A HEDGE MAY BE NEEDED FOR CNTRL SWATH OF CNTIES BUT THINK ADVISORY OUTLINE AS IS SHOULD SUFFICE SINCE GIVEN STEADY CIGS/DPS AT GRI/HSI...WHICH WOULD BE WRN ADVSRY BDR. SN GRADIENT WL PROBABLY END UP BEING FAIRLY TIGHT WITH THIS SITUATION. OTHERWISE...COLD THE REST OF THE WEEK WITH WARMING THROUGH THE WEEKEND. NRN PLNS/UPR MS VALLEY CLIPPER CURRENTLY PROGGED TO DRAG MORE WARM AIR OFF THE HIGH PLNS THAT REINFORCE COLD...SO WL BUMP SAT TEMPS UP AGAIN. DAYS 6...7 AND BEYOND LKG INTERESTING WITH MAGNITUDE OF COLD AIR GFS PROGGED OVR THE CONUS. WL CONT TO TREND TEMPS DOWN IN THOSE TIME FRAMES...BUT NOT AS DRAMATIC AS FMR NMBRS JUST YET. .GID...WINTER WEATHER ADVISORY CONTINUES TONIGHT FOR VALLEY... SHERMAN...GREELEY...HOWARD...NANCE...MERRICK... HAMILTON...POLK ...YORK... AND FILLMORE COUNTIES. 9 ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1015 PM EST WED JAN 15 2003 LAKE EFFECT SNOW BAND CONTINUES TO DROP SOUTHWARD AS FLOW BECOMES MORE NW. LET ADV OVR NRN ONEIDA COUNTY EXPIRE AS ACTIVITY WILL DIMINISH TO SCATTERED SHSN'S SHORTLY. WITH NW FLOW PERSISTING OVERNIGHT EXTENDED LIKELY POPS THROUGH THE OVERNIGHT PERIOD ACROSS NRN ZONES. CONTINUE TO THINK ACCUM ACROSS ONON/MADISON/SRN ONEIDA COUNTIES WILL REMAIN BELOW ADV CRITERIA BECAUSE LAKE INDUCED CAPES DECREASE OVERNIGHT/SHEAR INCREASES AND RADARS CONTINUE TO SHOW BEST REFLECTIVITIES NOT EXTENDING VERY FAR INLAND. NO CHANGES TO REST OF FORECAST. RRM ...PREVIOUS AFD... MEDIUM RNG GUIDANCE SHOWS LTL HOPE FOR A WARMUP ANY TIME SOON. VERY AMPLIFIED PTRN TO CONTINUE, AND SOME INDICATIONS THAT THE PTRN MAY RETROGRADE A BIT DAYS 6-10. THIS WOULD GIVE OUR FCST AREA A BETTER CHC FOR A SIG SYNOPTIC SNOW EVENT. UNTIL THAT OCCURS, WE'LL BE UNDER THE INFLUENCE OF GNRLY MSTR-STARVED NRN STREAM S/WV'S, AND PERIODIC BOUTS OF LAKE EFFECT SNOW IN THE FAVORED AREAS. MDLS SHOW ANOTHER S/WV PASSING THE RGN THIS EVNG, WHICH WILL ALLOW THE LOW LVL FLOW TO BCM A LTL MORE NWLY AFTER 21Z, SO BAND E OF LAKE ONTARIO XPCTD TO DROP SWD LATE TDA AND THIS EVNG. INTERESTING THAT BEST REFLECTIVITIES TDA HAVE NOT BEEN XTNDG INLAND VERY FAR, WITH HIGHEST RETURNS GNRLY STAYING IN OSWEGO COUNTY. PROFILES SHOW DECENT INSTABLILTY THIS EVENG, AND UNIDIRECTIONAL FLOW SLOWLY VEERING FROM 290 TO 310 BETWEEN 00Z AND 06Z, THEN FLOW LIGHTENS UP AND INVERSION STARTS TO LOWER. MESOETA AND RUC SUGGEST BEST POTNL FOR +SHSH WILL BE BETWEEN 23Z AND 03Z OVER FAR NRN/NW ONONDAGA, WHERE WE COULD FLIRT WITH LOW END ADVISORY ACCUMS. ATTM PLAN IS TO KEEP THE ADVISORY UP FOR NRN ONEIDA FOR THE REMAINDER OF THE AFTN INTO ERLY EVNG. WE'LL CONTINUE WITH ACCUMS IN THE 1-3 OR 2-4 INCH RNG FOR SYR/UCA AREAS, AND MENTION PSBLTY OF LCLY HIGHER ACCUMS ACRS FAR NRN/NW ONON. MAYBE AN INCH OR TWO FOR NRN AREAS OF CORTLAND/CHENANGO AND OTSEGO COUNTIES. ELSEWHERE XPCT ONLY FLURRIES. WEAK RIDGING TMRW. QUESTION IS WHETHER WE'LL SEE PARTLY SUNNY SKIES DVLP AS PER CRNT FCST. MDLS SUGGEST LOWER DECK PERSISTING WELL INTO THE MRNG HRS, THEN HIGHER CI DECK MOVS IN DURING THE AFTN. SUPPOSE WE COULD SEE A FEW HRS OF SUNSHINE INBETWEEN SO WILL BE OPTIMISTIC AND MENTION SOME INTERVALS OF SUN. S/WV TRACKING TWDS THE MID ATLC ON THU NGT, WITH ASSCD SFC LOW MOVG OFF THE CST NEAR CAPE HATTERAS BY FRI MRNG. APPEARS THAT THE NRN STREAM S/WV WILL HELP TO SUPPRESS THIS SYSTEM TO OUR SOUTH. IT'S ASSCD CDFNT SHUD BE ENTERING WRN NY BY 12Z FRI. THE FNT WILL PRBLY JUST BE ABSORBED INTO THE NW FLOW BEHIND THE DEPARTING CSTL LOW. COULD SEE SOME -SN ACRS FAR SRN/SE ZONES WITH MID ALTC SYSTEM THU NGT, BUT PROGS INDICATE MAIN PCPN SHIELD WILL BE WELL S OF THE RGN. WILL JUST GO WITH CHC POPS ALL ZONES FOR SNOW SHOWERS, DUE TO COMBINATION OF POTNL EFFECTS FROM BOTH SYSTEMS. XTNDD...ON FRIDAY THE NRN STREAM S/WV MOVS THRU AND MID ATLC SYSTEM CONTINUES TO MOVE NE AND OUT TO SEA, SO IMPVNG CONDITIONS XPCTD. FRI NGT AND SATURDAY LOOK PRETTY QUIET AT THIS POINT, WITH NXT CLIPPER-TYPE SYSTEM APRCHNG SATURDAY NGT. LES POTNL IN THE BGM FCST AREA TO FOLLOW SPCLY SUNDAY NGT INTO MONDAY. BASICALLY A CONTINUATION OF THE CRNT PTRN. .BGM...NONE. RHB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 135 PM EST WED JAN 15 2003 MEDIUM RNG GUIDANCE SHOWS LTL HOPE FOR A WARMUP ANY TIME SOON. VERY AMPLIFIED PTRN TO CONTINUE, AND SOME INDICATIONS THAT THE PTRN MAY RETROGRADE A BIT DAYS 6-10. THIS WOULD GIVE OUR FCST AREA A BETTER CHC FOR A SIG SYNOPTIC SNOW EVENT. UNTIL THAT OCCURS, WE'LL BE UNDER THE INFLUENCE OF GNRLY MSTR-STARVED NRN STREAM S/WV'S, AND PERIODIC BOUTS OF LAKE EFFECT SNOW IN THE FAVORED AREAS. MDLS SHOW ANOTHER S/WV PASSING THE RGN THIS EVNG, WHICH WILL ALLOW THE LOW LVL FLOW TO BCM A LTL MORE NWLY AFTER 21Z, SO BAND E OF LAKE ONTARIO XPCTD TO DROP SWD LATE TDA AND THIS EVNG. INTERESTING THAT BEST REFLECTIVITIES TDA HAVE NOT BEEN XTNDG INLAND VERY FAR, WITH HIGHEST RETURNS GNRLY STAYING IN OSWEGO COUNTY. PROFILES SHOW DECENT INSTABLILTY THIS EVENG, AND UNIDIRECTIONAL FLOW SLOWLY VEERING FROM 290 TO 310 BETWEEN 00Z AND 06Z, THEN FLOW LIGHTENS UP AND INVERSION STARTS TO LOWER. MESOETA AND RUC SUGGEST BEST POTNL FOR +SHSH WILL BE BETWEEN 23Z AND 03Z OVER FAR NRN/NW ONONDAGA, WHERE WE COULD FLIRT WITH LOW END ADVISORY ACCUMS. ATTM PLAN IS TO KEEP THE ADVISORY UP FOR NRN ONEIDA FOR THE REMAINDER OF THE AFTN INTO ERLY EVNG. WE'LL CONTINUE WITH ACCUMS IN THE 1-3 OR 2-4 INCH RNG FOR SYR/UCA AREAS, AND MENTION PSBLTY OF LCLY HIGHER ACCUMS ACRS FAR NRN/NW ONON. MAYBE AN INCH OR TWO FOR NRN AREAS OF CORTLAND/CHENANGO AND OTSEGO COUNTIES. ELSEWHERE XPCT ONLY FLURRIES. WEAK RIDGING TMRW. QUESTION IS WHETHER WE'LL SEE PARTLY SUNNY SKIES DVLP AS PER CRNT FCST. MDLS SUGGEST LOWER DECK PERSISTING WELL INTO THE MRNG HRS, THEN HIGHER CI DECK MOVS IN DURING THE AFTN. SUPPOSE WE COULD SEE A FEW HRS OF SUNSHINE INBETWEEN SO WILL BE OPTIMISTIC AND MENTION SOME INTERVALS OF SUN. S/WV TRACKING TWDS THE MID ATLC ON THU NGT, WITH ASSCD SFC LOW MOVG OFF THE CST NEAR CAPE HATTERAS BY FRI MRNG. APPEARS THAT THE NRN STREAM S/WV WILL HELP TO SUPPRESS THIS SYSTEM TO OUR SOUTH. IT'S ASSCD CDFNT SHUD BE ENTERING WRN NY BY 12Z FRI. THE FNT WILL PRBLY JUST BE ABSORBED INTO THE NW FLOW BEHIND THE DEPARTING CSTL LOW. COULD SEE SOME -SN ACRS FAR SRN/SE ZONES WITH MID ALTC SYSTEM THU NGT, BUT PROGS INDICATE MAIN PCPN SHIELD WILL BE WELL S OF THE RGN. WILL JUST GO WITH CHC POPS ALL ZONES FOR SNOW SHOWERS, DUE TO COMBINATION OF POTNL EFFECTS FROM BOTH SYSTEMS. XTNDD...ON FRIDAY THE NRN STREAM S/WV MOVS THRU AND MID ATLC SYSTEM CONTINUES TO MOVE NE AND OUT TO SEA, SO IMPVNG CONDITIONS XPCTD. FRI NGT AND SATURDAY LOOK PRETTY QUIET AT THIS POINT, WITH NXT CLIPPER-TYPE SYSTEM APRCHNG SATURDAY NGT. LES POTNL IN THE BGM FCST AREA TO FOLLOW SPCLY SUNDAY NGT INTO MONDAY. BASICALLY A CONTINUATION OF THE CRNT PTRN. .BGM...LAKE EFFECT SNOW ADVISORY INTO THIS EVENING FOR NORTHERN ONEIDA COUNTY. RHB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 945 AM EST WED JAN 15 2003 CURRENT FCST PACKAGE ON TRACK WOTH BREEZY AND COLD COND. LATEST GUIDANCE STILL SUGGESTING TEMPS WIL STRUGGLE TO REACH THE LOWE TO MID 40S WITH GUSTY NW WINDS AND CAA THRU THE AFTN. NO UPDATES NEEDED. MARINE: WL LEAVE SCA POSTED INTO THIS AFTERNOON. THIS BASED ON CURRENT OBS...AND THE FACT THAT MOST NWP GUID SHOW THE MOST SIGNIF DECRS IN WINDS AFTER 18Z. RUC 10 AND 40...WHICH APPEAR TO BE HANDLING CURRENT OBS BEST SUGGEST MARGINAL SCA CONDITIONS LASTING ALL AFTERNOON MAINLY FROM CLKN7 TO HAT OR OREGON INLET. .MHX...SCA ALL WATERS. nc FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 750 PM CST WED JAN 15 2003 .CURRENT OBSERVATIONAL OVERVIEW... 01Z MSAS ANALYSIS DEPICTED RIDGE OF ARCTIC HIGH PRESSURE FROM SASK PROVINCE TO NORTHERN IOWA. LATEST WATER VAPOR IMAGERY INDICATED WELL PRONOUNCED SHORTWAVE TROUGH DROPPING SOUTHEAST FROM CENTRAL SOUTH DAKOTA. IR SATELLITE IMAGERY SHOWED REGION UNDER THE NORTHERN PERIPHERY OF AFOREMENTIONED SHORTWAVE ENERGY WITH RESULTANT CANOPY OF HIGH CLOUDS EVIDENT OVER CWFA. .FORECAST DETAILS... MAIN FORECAST DILEMMA OVERNIGHT IS EXTENT OF MERCURY DROP WITH EXPECTED SKY COVER TRENDS I.E HIGH CLOUDS. EXAMINATION OF 00Z RUC SUGGESTS HIGH LEVEL MOISTURE WILL LINGER THROUGH AT LEAST 06Z FROM CENTRAL RED RIVER VALLEY SOUTH AND EAST ...PER LAYERED 500-300MB LAYERED RH FIELDS. THIS SCENARIO APPEARS REASONABLE BASED ON LATEST SATELLITE TRENDS. WILL AWAIT ARRIVAL/INGESTION OF 00Z MODEL RUNS BEFORE PASSING FINAL JUDGMENT ON PROJECTED /INHERITED OVERNIGHT LOWS. .FGF...NONE. BERG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 630 PM CST WED JAN 15 2003 LATEST RADAR IMAGERY INDICATES SNOW CONTINUING ACROSS SOUTHWEST PORTIONS OF THE CWA...BUT WITH DISTANCE FROM SURROUNDING RADARS HARD TO DETERMINE INTENSITY IN THIS AREA. SFC OBS OUT OF KPIR STILL INDICATING MODERATE SNOW AND CALLS MADE TO LAW ENFORCEMENT IN THE REGION INDICATES 5 TO 6 INCHES ALREADY ON THE GROUND WITH SNOW CONTINUING. 21Z RUC SHOULD GOOD MID LVL OMEGA AND WEAK UPGLIDE ON 280K SFC THROUGH ABOUT 03Z...BEFORE THE UPGLIDE BEGINS TO SLIDE TO THE SOUTHEAST. WITH CONDENSATION PRESSURE DEFICITS LESS THAN 10MB AND SUFFICIENT FORCING IN PLACE FOR SNOW TO CONTINUE FOR ANOTHER FEW HOURS HAVE OPTED TO TAKE ADVISORY TO A WARNING ACROSS THE FAR SOUTHWEST AND MENTION TOTAL ACCUMULATIONS IN THE 6 TO 8 INCH RANGE. WHILE SOME AREAS LIKELY WILL REMAIN BELOW WARNING CRITERIA...FEEL 6 INCH AMOUNTS WILL BE WIDESPREAD ENOUGH...ESPECIALLY NEAR INTERSTATE...TO WARRANT MOVING TO HEAVY SNOW WARNING WORDING FOR MUCH OF THE REMAINDER OF THE EVENING. .ABR...HEAVY SNOW WARNING FOR FAR SOUTHWEST CWA THROUGH 05Z. WINTER WEATHER ADVISORY FOR SNOW SULLY...HAND AND HYDE COUNTIES UNTIL 03Z. MLF sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 925 PM CST WED JAN 15 2003 ONLY MINOR ADJUSTMENTS WILL BE MADE TO THE FORECAST FOR THE OVERNIGHT PERIOD. REST OF FORECAST PERIODS APPEARS ON TRACK. THIS EVENING...THICK HIGH CLOUDS WERE STREAMING OVER MID TN AHEAD OF THE APPROACHING SYSTEM. LOW/MID LEVEL RIDGING WAS EXTENDING FROM THE NORTHERN PLAINS...SOUTHEAST ACROSS THE OHIO VALLEY AND INTO MID TN. SURFACE DEW POINTS REMAINED LOW OVER MID TN...IN THE SINGLE DIGITS AND TEENS. TEMPERATURES WERE SLOWLY FALLING IN THE UPPER 20S. THE WELL ADVERTISED SURFACE LOW WAS MOVING OUT OF THE TEXAS PANHANDLE...BOUND FOR JUST SOUTH OF MEMPHIS BY MORNING...AND INTO NORTH AL BY AFTERNOON. QUICK LOOK AT LATEST DATA STILL SUPPORTS THURSDAY FORECAST. NO NEED TO CHANGE ANY HEADLINES AT THIS POINT. BULK OF PRECIPITATION WILL NOT BE AFFECTING MID TN UNTIL LATE MORNING AND MAINLY AFTERNOON...SO OVERNIGHT SHIFT CAN MAKE DECISION ON EXACTLY WHICH LOCATIONS SHOULD BE ADVANCED INTO WARNING/ADVISORY HEADLINES. FOR NOW WILL STICK WITH WINTER STORM WATCH MOST OF MID TN. LATEST ETA/RUC BASICALLY IN AGREEMENT WITH PREVIOUS RUNS REGARDING TRACK OF LOW. HOWEVER...NOTICED MODEL QPF FORECASTS ARE LOWER. NEW ETA YIELDS AROUND 0.20 WHILE NGM GIVE A MEASLY 0.07. ON THE PLUS SIDE...THIS IS A PRETTY STRONG SYSTEM WITH STRONG UVV AND VERY COLD TEMPERATURES ALOFT (-30C AT H5). MID TN TEMPERATURES HAVE BEEN COLD...SO SURFACES ARE PRIMED TO COLLECT SNOW. THE DOWN SIDE FOR SNOW LOVERS IS THAT SYSTEM WILL BE MOVING THROUGH RATHER QUICKLY...NOT ABLE TO SCOOP UP MUCH GULF MOISTURE. FOR NASHVILLE METRO...LOOKS LIKE THE ACCUMULATING WILL OCCUR DURING A FEW HOUR PERIOD THURSDAY AFTERNOON. EVEN WITH BELIEVABLY LOWER QPF FROM LATEST MODELS...VIGOR OF SYSTEM COULD RESULT IN A FEW GOOD BURSTS OF SNOW THURSDAY AFTERNOON AND EVENING. .BNA...WINTER STORM WATCH THURSDAY FOR THE NORTHERN THREE QUARTERS OF MIDDLE TN. ...WINTER STORM WATCH THURSDAY AND THURSDAY EVENING FOR THE CUMBERLAND PLATEAU. $$ 13 tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 210 AM CST THU JAN 16 2003 .OVERVIEW...WINTER STORM NOW IMPACTING AREA WITH LEADING EDGE OF PRECIPITATION EXTENDING FROM WILLIAMSBURG TO ROSEVILLE MOVING EAST NORTHEAST AT 15 MPH. NOWCAST TOOLS OF RADAR...SFC AND SATELLITE SHOW SYSTEM TO AFFECT SOUTHERN 1/3 OF AREA FOR ANOTHER 6 HOURS AND THE FAR SOUTH AS LONG AS ANOTHER 8+ HOURS. SNOW ACCUMULATION TRENDS UPSTREAM SUGGEST HIGHWAY 34 AND SOUTH TO EXPERIENCE 3 TO 6 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE DEPENDING ON DEFORMATION ZONE. WILL MONITOR FOR POTENTIAL UPGRADE TO WARNING CRITERIA. UPPER AIR SUGGEST ACTIVE PATTERN IN NW FLOW WITH UPSTREAM IMPULSES MOVING ALONG BAROCLINIC ZONE. HEIGHT RISES UPSTREAM SUGGEST CLEARING TOMORROW LATE. ...STORM TOTAL AMOUNTS AND TIMING ENDING TO FLURRIES WITH POTENTIAL WARNING DECISION NEAR TERM FORECAST ISSUE... .DIAGNOSIS AND DAY 1-3...AVN BEST ON PRECIPITATION COVERAGE AT 06Z. PLAN TO USE ETA FORCING WITH AVN AND MINOR INPUTS FROM RUC TRENDS INTEGRATED WITH NOWCAST TOOLS. THIS CURRENTLY SUPPORTS NORTHERN EDGE MAKING UP TO AROUND I-80 TOWARD DAYBREAK BEFORE SLIDING BACK SE. FAR SOUTH 1-2 ROWS OF COUNTIES TO SEE LONGEST PERIOD OF LIGHT TO OCCASIONALLY MODERATE SNOW AT 20 TO 25 TO 1 RATIOS. AT .25 TO .5 INCH PER HOUR ACCUMULATION RATES FOR ANOTHER 4-8 HOURS WITH 2 TO 3 INCHES ALREADY ON GROUND...LEADS TO STORM TOTALS OF 3-7 INCH AMOUNTS THERE WITH LOCALLY HIGHER AMOUNTS. SEE WHAT HAPPENS NEXT COUPLE HOURS AS GET MORE REPORTS ON ACCUMULATION RATES...AGAIN MAY HAVE TO BREAK OUT FAR SOUTHERN ONE OR TWO ROWS OF COUNTIES AND GO WITH A WARNING WITH 4 AM PACKAGE. THEN...CLEARING TO MOVE IN FROM NW WITH MAY BE FLURRIES LEFT FAR SOUTH BY MID DAY. WILL THEN TRY AND INCORPORATE SNOW TO LOWER TEMPS THERE NEXT COUPLE OF DAYS. SATURDAY...STRONG UPPER SYSTEM SHOWN BY ALL MODELS SUGGESTS GOING WITH LIKELY POPS WITH 850 TEMPS OF -10 TO -15C FOR 20 TO 25 TO 1 RATIOS...THIS SUPPORTS 1-2 INCH AMOUNTS WITH LOCALLY HIGHER AMOUNTS WITH A POTENTIAL DEFORMATION ZONE COULD SEE SLIGHTLY HIGHER BUT LIKELY WILL TAKE ANOTHER 24 HOURS OF SO FOR MODELS TO BETTER CAPTURE AND THUS ASSESS THIS. .EXTENDED (SUN-THU)...NW FLOW CONTINUES PER ALL MODELS WITH CHANCE OF LIGHT SNOW ALMOST EVERY DAY WITH ANOTHER 3 WEAK TO MODERATE STRENGTH ALBERTA CLIPPERS. MORE OMINOUS IS SUGGESTING OF REX OMEGA BLOCK ALL NEXT WEEK OF ARCTIC AIR POOLING FOR EXTENDED COLD PERIOD WITH ARCTIC AIR TRAPPED IN CENTRAL NA. PATTERN HAS BEEN CONSISTENTLY SHOWN IN ONE FORM OR ANOTHER BY ALL MODELS FOR SEVERAL DAYS NOW...NOT GOOD UNLESS LIKE COLD TEMPS. .DVN... IA...WINTER WEATHER ADVISORY THURSDAY AM ALONG AND SOUTH OF HIGHWAY 34. IL...WINTER WEATHER ADVISORY THURSDAY AM ALONG AND SOUTH OF HIGHWAY 34. MO...WINTER WEATHER ADVISORY THURSDAY AM. NICHOLS il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 145 AM MST THU JAN 16 2003 FORECAST CONCERNS ARE WINDS TODAY AND POSSIBLE ARTIC OUTBREAK TOWARD THE END OF NEXT WEEK. TODAY-FRIDAY...UPPER STORM SYSTEM THAT BROUGHT A SKIF OF SNOW TO PARTS OF THE FORECAST AREA WILL CONTINUE TO EXIT THE AREA. FORECAST CONCERN TODAY IS EXTENT OF WINDS. PRESSURE DIFFERENCE BETWEEN THE INCOMING HIGH AND DEPARTING LOW COMBINED WITH STRONG WINDS AND DOWNWARD MOTION IN THE 850-700/700-500 LAYER SUGGEST WINDY CONDITIONS OVER THE WESTERN HALF OF THE FORECAST AREA. FURTHER EAST WINDS NOT AS STRONG AND LOWER ELEVATION SUGGEST A BIT LESS WIND. FSL RUC II NOT AS EXCITED ABOUT STRENGTH OF WINDS COMPARED TO WHAT IT HAD YESTERDAY AND VARIOUS MOS GUIDANCE PRODUCTS FOLLOW SUITE. HIGHS TODAY RANGE FROM 25 TO 30 OVER THE EAST TO THE LOWER 30S WEST PER 850 TEMPS...BACKED UP WITH FWC GUIDANCE. ON FRIDAY TEMPS A BIT WARMER WITH READINGS IN THE MID 30S EAST...NEAR 40 WEST. LOWS TONIGHT WILL BE CHILLY GIVEN FAVORABLE RADIATIONAL COOLING. WILL GO WITH COLDER OF THE GUIDANCE NUMBERS. FRIDAY NIGHT-SUNDAY...FORECAST AREA REMAINS UNDER INFLUENCE OF NORTHWEST FLOW ALOFT AS UPPER RIDGE REMAINS TO OUR WEST AND DEEP/BROAD TROUGH REMAINS TO OUR EAST. HIGHS SATURDAY 35 TO 40 PER 850 TEMPS FROM ETA/AVN AFTER MORNING LOWS FRIDAY NIGHT IN THE TEENS. HIGHS ON SUNDAY MUCH WARMER WITH SOUTHWEST WINDS AND LEE TROUGH INFLUENCE. 850 TEMPS SUPPORT HIGHS AROUND 55. MONDAY-WEDNESDAY...FORECAST AREA REMAINS UNDER INFLUENCE OF BROAD UPPER TROUGH. FOCUS WILL BE ON STRENGTH OF ARTIC FRONT WHICH BACKS INTO THE AREA BY MIDWEEK. WILL LEAVE THINGS AS IS AT THIS TIME. .GLD...NONE. DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 217 AM CST THU JAN 16 2003 DEVELOPING WINTER STORM STILL POSING CONCERNS REGARDING SNOWFALL AMOUNTS...TIMING...ETC. WIND PROFILER TIME SECTIONS FROM NEDOSHA AND HEBRON KANSAS...AS WELL AS PROFILER NETWORK IN OK ARE SUGGESTING CLOSED CIRCULATION AT 925 MB/850 MB OVER SERN KS AT 06Z...WITH AN IMPLIED PROGRESSIVE OPEN WAVE /TROUGH/ AT 500 MB. THESE FEATURES WERE MOVING DUE EAST AND PHASING IN WITH THE UPPER TROUGH. THE NET INCREASE IN LIFT SHOULD ALLOW FOR A RAPID EXPANSION OF THE SNOW SHIELD ACROSS SOUTHERN MISSOURI THROUGH 12Z. AVN/RUC KEEP THE SURFACE LOW FURTHER S ACROSS CNTRL/SRN AR THROUGH 15Z THU. MSAS 3 HR PRESSURE FALLS DO SHOW DISTINCT RISE/FALL SIGNATURES LEADING INTO NWRN MS. HOWEVER...DEEPER SURFACE PRESSURE FALLS /1-2MB/ SHOW UP ACROSS SOUTHERN IL IN THE VICINITY OF A WEAK E-W ORIENT SFC-925 MB TROUGH. I AM INCLINED TO TRANSLATE THE SURFACE LOW A LITTLE FURTHER NORTH ALONG THE SW MO/NWRN AR BORDER OVERNIGHT...GRADUALLY MOVING BETWEEN MEM-MKL BETWEEN 15-18Z THIS MORNING....EVENTUALLY MOVING SOUTH OF BNA BY 00Z. THE 11-3.9 MICRON SATELLITE DIFFERENCING CHANNEL SHOW SFC-850 MB MOISTURE ACROSS ERN TX...ALL OF ARK AND LA AT 07Z THIS MORNING. THIS IS JUST TO THE EAST AND SOUTHEAST OF THE LOW AND THERMAL RIDGE THAT WAS ORIENTED FROM SWRN MO THROUGH CENTRAL IL ON THE MANDATORY LEVEL UPPER AIR CHARTS AT 00Z THURSDAY. THE INCLUSION OF THIS LOWER LEVEL MOISTURE...ALONG WITH THE UPPER LEVEL SEEDER-FEEDER ICE CRYSTALS...SHOULD LEAD TO RAPID SNOW DEVELOPMENT THIS MORNING. AT THIS TIME...I AM INCLINED TO LEAN CLOSER TO A 12 TO 1 SNOW RATIO AS THE SNOW WORKS ACROSS THE SOUTHERN BORDER COUNTIES OF SOUTHEAST MISSOURI AND WESTERN KENTUCKY...WITH 15 TO 1 RATIO FURTHER IN THE NORTHERN 1/2 OF THE CWA. I SUSPECT THIS WILL SHAVE OFF AN INCH OR SO IN TOTAL ACCUMULATION IN THE SOUTH. IN THE NORTH 1/2 OF THE PAH FORECAST AREA...I AM CONCERNED THAT DEFORMATION SNOW/WARM CONVEYOR BELT PCPN REGIME MAY BE TOO HIGH...SO WILL CONSIDER LOWER MAX SNOWFALL TOTALS BACK TO THE 3-5 INCH RANGE...ACROSS SOUTHWEST INDIANA AND OVER SOUTHERN ILLINOIS...NORTH OF CRAWLEYS RIDGE / IL ROUTE 13/. SNOWFALL AMOUNTS SHOULD BE SOMEWHAT ENHANCED AROUND MID MORNING /14-16Z/ OVER SERN MO BY SOME UPSLOPE FLOW. AS THE MORNING PROGRESSES...SNOW ACCUMULATION WILL DIP A LITTLE OVER SOUTHERN IL AND EXTREME WESTERN KENTUCKY...UNTIL THE COLDEST AIR WITH THE UPPER LEVEL TROUGH MOVES OVER THE WARM CONVEYOR BELT...SHARPENING LAPSE RATES OVER EXTREME SOUTHERN KENTUCKY. ISOLATED THUNDERSTORMS MAY BE POSSIBLE SOUTH OF A MAYFIELD...BENTON KENTUCKY LINE DURING THE LATE MORNING EARLY AFTERNOON...WITH THE BEST PROBABILITY OF UPRIGHT CONVECTION/I.E. THUNDERSTORMS FROM THE LAND BETWEEN THE LAKES...EASTWARD TO GREENVILLE KENTUCKY...INCLUDING HOPKINSVILLE. THIS MAY LEAD TO SOME ISOLATED HIGH SNOW TOTALS. FOR THE SOUTHERN 1/2 OF THE CWA...WILL LIKELY LEAN TOWARD A 3 TO 7 INCH SNOWFALL TOTAL FOR TODAY. SUSPECT THE HEAVIEST SNOW WILL LIE NEAR A LINE FROM LAKE WAPPAPPELLO MO...MAYFIELD AND HOPKINSVILLE KY TODAY. I WILL LEAVE THE WINTER STORM WARNING IN THROUGH EARLY THIS EVENING...WITH THE MAIN HAZARD DURING THE LATE AFTERNOON AND EARLY EVENING ASSOCIATED WITH BLOWING SNOW AND WIND CHILLS. THE DAY CREW MAY WISH TO REVISIT THE EXPIRATION TIME...IF THE SYSTEM MOVES FASTER THAN EXPECTED TODAY. DEPENDING ON THE SNOW COVER...AND GIVEN THE SIGNIFICANT DROP IN THICKNESSES OVER THE REGION TONIGHT AND FRIDAY...I WILL CONSIDER DROPPING TEMPS A CATEGORY FOR FRIDAY NIGHT INTO EARLY SATURDAY. GIVEN THE CURRENT WEATHER...DO NOT PLAN TO TINKER MUCH WITH THE 3-7 DAY PORTION OF THE FORECAST AT THIS TIME. THANKS LSX FOR COORDINATION ON SNOWFALL AMOUNTS. .PAH....WINTER STORM WARNING TODAY THROUGH EARLY THIS EVENING FOR THE ENTIRE CWA. $$ SMITH ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 306 AM EST THU JAN 16 2003 LONG AWAITED SFC LOW HAS APPEARED ON THE SURFACE ANALYSIS OVER NRN TEXAS. ETA/GFS/NGM APPEAR TO HAVE BETTER AGREEMENT ON THE EVENTUAL TRACK OF THE LOW TONIGHT AND FRIDAY. THE BIGGEST CHANGE FROM PREVIOUS FCST RUNS IS THE AMOUNT OF MOISTURE THAT LINGERS OVER OUR CWA DURING THE DAY FRIDAY AS POTENT SECONDARY MID-LEVEL VORT CENTER MOVES ACROSS THE CWA IN CONCERT WITH COLDER AIR WRAPPING IN AROUND THE BACKSIDE OF THE DEPARTING SFC LOW. BIGGEST QUESTIONS REGARDING THE EVOLUTION OF A WINTER WX EVENT FOR OUR CWA WILL BE: 1. HOW LOW CAN THE DEWPOINTS STAY BEFORE ONSET OF PRECIP TONIGHT? 2. HOW MUCH DYNAMIC COOLING OCCURS IN THE COLUMN WITH THE STRONG OMEGA FCST BETWEEN 06Z-12Z TONIGHT? 3. HOW MUCH MOISTURE WILL BE LEFT THROUGH 18Z FRIDAY WHEN THE STRONGEST CAA TAKES PLACE? USING A COMPOSITE OF THE VARIOUS CRITICAL THICKNESS VALUES...H8 TEMPS AND LOW TRACKS...I CAME UP WITH THE FOLLOWING SCENARIO. FOR OUR NRN COUNTIES FROM GREENE/PITT OVER TO THE NRN OUTER BANKS PRECIP STARTS AS A MIX OF RAIN/SNOW CHANGING TO ALL SNOW LATE TONIGHT INTO EARLY FRIDAY WITH ACCUMULATION AROUND AN INCH. FOR THE ISO-EWN-OCW CORRIDOR...EXPECT PRECIP TO START AS RAIN THEN BECOMING A MIX OF RAIN/SNOW LATE TONIGHT THEN ALL SNOW FRIDAY WITH ACCUMULATIONS ONE INCH OR LESS. ALONG COASTAL SECTIONS...THE BIG QUESTION IS HOW MUCH LOW-LEVEL MARINE AIR INVADES THE AREA. WILL GO WITH ALL RAIN TONIGHT...CHANGING TO SNOW EARLY FRIDAY WITH ACCUMULATIONS OF 1/2 INCH UP TO POSSIBLY AN INCH. NO WSW WILL BE REQUIRED...BUT THE DAYSHIFT WILL HAVE TO TAKE A LOOK AT POSSIBLE ADVISORIES. FOR TEMPS...WILL USE A MODEL BLEND...BUT WILL LEAN TOWARD COLDER READINGS FRIDAY BASED ON PRECIP. EXTENDED: GENERAL MEAN TROF TO REMAIN PARKED OVER THE ERN US WITH OCCASIONAL CLIPPER TYPE SYSTEMS THRU THE MIDDLE OF NEXT WEEK. SOME MODERATION IN TEMPS IS INDICATED TOWARD THE END OF NEXT WEEK. MARINE: AFTER OPC COORD CALL AND DELIB WITH ILM WILL ISSUE GALE WARNING FROM HAT SWD TO SURF CITY AS LOW LVL JET RACES UP THE COAST BETWEEN 06Z-12Z TONIGHT. GALE EVENT ITSELF APT TO BE SHORT DURATION BUT THINK 10M WINDS AT FSPN7 AND DSLN7 WILL VERIFY FOR US. STRONG SCA COND XPTD ELSEWHERE BUT WILL NOT RAISE FLAGS YET AS WE ARE STILL BEYOND 12 HOUR WINDOW. POPULATED GRIDS IN EARLY PERIODS WITH RUC10 WHICH SEAMED UP VERY WELL WITH GFS SOLN. CAA AFTER 12Z FRI WILL KEEP SOLID SCA COND ALL WATERS. WIND AND SEAS TREND DOWNWARD INTO SAT BUT INCREASES IN A W TRAJ SUNDAY AS HIGH ANCHORS OVER THE NRN GOMEX AND LOW PRES MOVES ACRS THE GRT LKS. DESPITE APPROACH OF FULL MOON TIDES AND WIND TRAJ NOT SUPPORTIVE OF LOCAL COASTAL OR SOUNDSIDE FLOODING. .MHX...GALE WARNING FROM CAPE HATTERAS SWD TO SURF CITY. FCSTID = 11/15 MHX 43 34 38 21 / 10 80 50 00 EWN 42 33 36 19 / 10 80 50 00 HSE 42 36 39 28 / 10 80 50 00 PGV 41 32 37 18 / 10 80 50 00 $$ PUBLIC/FIRE...COLLINS MARINE/AVIATION...COLBY nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 326 AM EST THU JAN 16 2003 HI PRESS RIDGE TO BUILD ACRS THE FA TODAY. TROF/CF TO MOVE DOWN ACRS SRN CANADA TODAY AND THEN ACRS THE FA TONITE AND ON FRI. ANOTHER RIDGE OF HI PRESS TO BUILD INTO THE FA ON FRI NITE/SAT. STORM SYS TO MOVE ACRS THE GREAT LKS REGION AND INTO SRN CANADA ON SAT NITE AND SUN. UPR TROF TO MOVE ACRS THE FA ON SUN. 00Z TAQ RUC SHOWS TEMPS TO BE IN THE SINGLE NUMBERS TO THE MID TEENS FROM EAST TO WEST ACRS THE FA TODAY WITH S-SW SFC WINDS AT 5-15 KTS. T1MAX TEMPS ARE IN THE UPR TEENS-M20S TODAY. FEW TWEAKS TO FIRST PERIOD TEMPS/WINDS BASED ON THIS DATA AND CURRENT MESONET OBS. SOME LOW-LVL MSTR TO LINGER ACRS THE FA TODAY (ESPECIALLY ACRS THE NRN TIER ZONES). PW VALUES LOOK TO BE BLO 0.25" ACRS THE FA TODAY THRU SAT NITE...AS SHOWN BY NH/NY FSL GPS IPW SITES ATTM. RUC SHOWS SOME PCPN POSSIBLE ACRS THE WRN ZONES BY LATER TODAY. H85 WAA TO TAKE PLACE ACRS THE FA TODAY...THEN GOOD CAA TO DEVELOP ACRS THE FA TONITE...FRI...AND EARLY ON FRI NITE. WK WAA TO AFFECT THE FA LATE ON FRI NITE AND INTO SAT. SOME LOW-LVL MSTR ADVECTION TO AFFECT THE FA TODAY. LOW-LVL MSTR TO LINGER ACRS THE FA TONITE AND INTO EARLY ON FRI...THEN RETURN AGAIN ON SUN. SOME MID-LVL MSTR TO AFFECT THE FA TONITE. BUFCAN/88D MOSAIC SHOWS THAT ANY -SHSN ACRS THE FA SHOULD BE DYING OUT SOON. WILL CONT TO HANDLE ANY LINGERING PCPN ACRS THE FA EARLY TODAY WITH THE STF. ETA BUFR DATA SHOWS THAT THE WRN FA SHOULD GET IN ON AT LEAST SOME LK INDUCED/ENHANCED MSTR BY LATER TODAY AND INTO EARLY TONITE. IR SAT PIX SHOW LESS CLD COVER UPSTREAM ACRS SRN CANADA ATTM. SOME CLEARING EXPECTED ACRS THE FA EARLY TODAY...THEN MORE CLDS BY LATER IN THE DAY ACRS THE FA WRN ZONES. WILL HANG ONTO MENTION OF FLURRIES ACRS THE WRN TIER FOR LATER TODAY AS SHEAR EXPECTED TO BE HI AND INSTABILITY EXPECTED TO BE RELATIVELY WK IN THIS REGION. CHC POPS BY LATER TONITE AND INTO EARLY ON FRI ACRS MOST ZONES LOOKS LIKE A GOOD IDEA WITH TROF/CF PASSAGE THEN. MSTR STILL EXPECTED TO BE LIMITED WITH THIS SYS. NEXT SHOT FOR ANY PCPN LOOKS TO BE LK INDUCED AGAIN ON SAT AND INTO SAT NITE WITH MORE WIDESPREAD PCPN EXPECTED ON SUN. POPS FROM PREVIOUS FCST MAY BE A LIL ON THE HI SIDE FOR THIS TIME-FRAME...BUT WILL HANG ONTO THEM FOR CONTINUITY SAKE FOR NOW. T1MAX TEMPS ARE +5-15F ON FRI WITH T1MIN TEMPS -5F TO +15F TONITE AND IN THE SINGLE NUMBERS ON FRI NITE. COLD WX TO CONT FOR A WHILE YET... BUT HEY...IT/S WINTER. NO MAJOR CHANGES TO MON THRU WED FCST FOR NOW. RUNNING A LIL LATE TODAY DUE TO A MINOR LOCAL COMPUTER GLITCH EARLIER...BUT ALL IS WELL NOW. WRK ZONES OUT UNDER ALBWRKCWF. FINAL ZFP BY 4 AM. .BTV...NONE. MURRAY vt SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1048 AM EST THU JAN 16 2003 AREA RADAR AND SURFACE OBS INDICATE A LARGE AREA OF SNOWFALL EXTENDING FROM THE MID MISSISSIPPI VALLEY TO NORTH CENTRAL INDIANA. THIS AREA OF SNOWFALL HAS DEVELOPED WITHIN SOME MID LEVEL DEFORMATION ASSOCIATED WITH A SHORT WAVE ROTATING THROUGH THE SOUTHERN MISSISSIPPI VALLEY. THE 12Z MESO ETA AND 14Z RUC SHOW SOME MID LEVEL DEFORMATION AND WEAK LIFT IN THE 700-500MB LAYER PASSING ACROSS THE FAR SOUTHERN COUNTIES THIS AFTERNOON. MODEL QPF FIELDS STILL KEEP THE PRECIP SOUTH OF THE STATE LINE. BASED ON THE DRY LAYER NOTED IN THE 900-850 MB LAYER AND THE VERY DRY AIR ON THE 12Z DTX SOUNDING...I WILL KEEP THE CURRENT DRY FORECAST GOING. PLENTY OF MID AND HIGH CLOUDS STREAMING ACROSS THE FORECAST AREA TO CARRY CLOUDY SKIES THIS AFTERNOON. LAKE STRATO CU IS ALSO SLOWLY TRYING TO ORGANIZE ACROSS SW LOWER MICHIGAN. BASED ON CURRENT TEMPS AND CLOUD COVER...I WILL KNOCK THE SOUTHERN COUNTIES FCST HIGHS DOWN A LITTLE BIT. OTHERWISE...NO CHANGES WILL BE MADE TO THE CURRENT FORECAST. .DTX...NONE. EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) CONSIDINE mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 149 PM EST THU JAN 16 2003 SHORT TERM DISCUSSION... FCST CHALLENGE WL BE ANY REMAINING SYNOPTIC SNOW SE THIS EVENING THEN SINGLE BAND LAKE EFFECT SNOW POTENTIAL LATE TONIGHT AND FRI MORNING. SYNOPTIC LOW MOVING EAST ACRS TN VALLEY AND EXPECTED TO CONT AN EASTWARD MOVEMENT. NRN FRINGE OF SNOW HAS JUST BEEN SKIRTING SRN COUNTIES. LATEST 88D RETURNS ARE DIMINISHING AND IF THIS TREND CONTINUES MAY DROP ALL MENTION OF MEASURABLE SNOW TONIGHT AWAY FROM LAKE MICHIGAN. LAKE EFFECT SNOW LATE TONIGHT A BIG CONCERN. 16/00Z RUC10 SHOWING IMPRESSIVE SFC CONVERGENCE IN WIND FIELD OVER EASTERN LAKE MICHIGAN DVLPG AROUND 06Z. EVEN LARGER RESOLUTION MODELS OF ETA/AVN/UW-NMS SHOWING SINGLE BAND FORMATION AND LAKE EFFECT SNOW. RUC10 RESOLUTION SHOULD HANDLE BAND MOVEMENT BETTER AND HAVE FOLLOWED. THIS MODEL DEVELOPS INITIAL BAND FROM BEH TO SBN THEN MOVES IT INTO SW BERRIEN...LAPORTE AND PORTER COUNTIES BY 09Z. OBVIOUSLY EXACT TIMING IMPOSSIBLE BUT TREND WL BE FOR A SLOW WESTWARD MIGRATION. BAND THEN APPEARS TO BECOME STATIONARY OVER SW BERRIEN AND WESTERN LAPORTE COUNTIES THROUGH ABOUT 18Z FRI. SFC-H8 FETCH EXPECTED TO BE QUITE LONG...FROM ABOUT 330 TO 360...WITH DELTA T VALUES INTO LOW 20S. MOISTURE IS PROGGED TO BE ABOVE 80 PERCENT THROUGH 850 MB BUT DRIES OUT QUICKLY BETWEEN 850 AND 700MB. THIS MOISTURE MOVES DOWN LM LATE TONIGHT AS SHORT WAVE OVER SRN CANADA MOVES SOUTH ACROSS LAKES. INVERSION RISES TONIGHT WITH THIS S/W THEN BEGINS TO LOWER ON FRI AFTN AS LOW LEVEL TEMP FIELDS WARM SLIGHTLY AND RIDGING/SUBSIDENCE MOVES IN. ONLY LIMITING FACTOR WITH THIS FEATURE WL BE DRY AIR ABOVE 850MB. CURRENT SNOW SCHEMES INDICATE 3 TO 6 INCHES...WITH POTENTIAL FOR LOCALLY MORE IN WESTERN LAPORTE IF THIS BAND INDEED SETS UP THERE. WL BE GOING WITH 1 TO 3 TONIGHT AND ANOTHER 1 TO 2 ON FRI...SO TOTAL OF 3 TO 5 YIELDS ADVISORY CRITERIA. WL ISSUE A WINTER WEATHER ADVISORY FOR LAKE EFFECT SNOW FOR LATE TONIGHT AND FRIDAY. 6 TO 9 HOUR WINDOW AND LIMITED MID LEVEL MOISTURE SHLD KEEP AMOUNTS IN CHECK BUT WL NEED TO WATCH CLOSELY. WL LEAVE STARKE OUT OF ADVISORY FOR NOW BUT WL NEED TO WATCH. MESOETA 850MB OMEGA STRETCHES INTO STARKE COUNTY FOR SEVERAL HOURS. ST. JOE INDIANA WL BE TRICKY ALSO BUT EXPECT A QUICK SHOT THERE TONIGHT THEN ONLY A BRIEF PERIOD ON FRI AS BAND DISSIPATES AND MOVES BACK EAST AS LOW LEVEL FLOW BACKS. NEXT SYSTEM JUST A TAD SLOWER BUT DPVA AND MOISTURE MOVE IN RAPIDLY SAT AFTN. CONTINUED WITH LIKELY POPS BUT TRIED TO ADD TIMING FOR AFTN AND SAT EVENING. AMOUNTS LOOKING TO BE BLO ADVISORY CRITERIA AS MOISTURE IS LIMITED...BUT COLD TEMPS WL YIELD HIGH LIQUID/SNOW RATIOS. CURRENT FCST AND MOS GUIDANCE CLOSE AND ONLY TWEEKED DOWN A BIT FOR FRI NIGHT AS AREA BELOW SYSTEMS AND POTENTIAL THERE FOR COLDEST NIGHT OF THE SEASON. MODELS STILL KEEP WINDS UP A BIT AS NEXT SYSTEM APPROACHES SO HAVE NOT BOTTOMED OUT MINS. EXTENDED DISCUSSION... HIGH PRESSURE OVER SOUTHEASTERN CONUS MOVES EAST ON SUNDAY NIGHT. PROGRESSIVE FLOW CONTINUES WITH COLD FRONT MOVING THROUGH ON MONDAY. ARCTIC RIDGE BUILDS IN ON TUESDAY. COLD AIR ALOFT WILL HELP TO KEEP LAPSE RATES FAIRLY STEEP. NORTHWESTERLY WINDS ACROSS LAKE MICHIGAN WILL ALSO HELP TO KEEP SKIES CLOUDY WITH A CHANCE OF SNOW. WEAK WARM AIR ADVECTION SETS UP TUESDAY NIGHT AHEAD OF NEXT SYSTEM OUT OF SOUTHERN PLAINS. UPPER FLOW REMAINS ZONAL SO THIS SYSTEM ALSO MOVES EAST THROUGH THE SOUTHEASTERN CONUS ON THURSDAY. DUE TO PROXIMITY OF SYSTEM WILL KEEP CHANCE OF SNOW IN FORECAST FOR WEDNESDAY AND THURSDAY. WITH LACK OF ANY RETURN FLOW TEMPERATURES SHOULD REMAIN BELOW NORMAL THROUGH EXTENDED. .IWX... IN...WINTER WEATHER ADVISORY FOR LATE TONIGHT THROUGH FRIDAY AFTERNOON FOR ZONE INZ003. MI...WINTER WEATHER ADVISORY FOR LATE TONIGHT THROUGH FRIDAY AFTERNOON FOR ZONE MIZ077. OH...NONE. LASHLEY/OHARA in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EST THU JAN 16 2003 12Z RAOBS/LATEST WV LOOP AND RUC ANLSYS SHOW FULL LATITUDE TROF IN ERN NAMERICA DOWNWND OF HI AMPLITUDE RDG OVR THE W. SVRL SHRTWVS OF CONCERN EMBEDDED WITHIN NW FLOW ALF BTWN THE RDG/TROF. THE FIRST IS DIVING S THRU ONTARIO...WITH COLD FNT ASSOCIATED WITH THIS SYS NOW MOVG INTO NRN ZNS. IMPRESSIVE H5 HGT RISE/FALL COUPLET ACCOMPANYING SHRTWV (12HR HGT RISE 160M AT YYQ TO 130M FALL AT YPL) AND N 40KT H85 WNDS FM YYQ TO INL HELPING TO DRIVE H5 VORT CENTER ALMOST DUE S. MAJOR SHRTWV BRINGING SN TO SCNTRL STATES SHUNTED TO THE S BY AGGRESSIVE SHRTWV IN NWLY FLOW ALF. ANOTHER SHRTWV OF NOTE MOVG OVR TOP OF RDG IN CNDN NW TERRITORIES. ...SHORT TERM (TONIGHT)... PLAN TO LEAVE ALL ADVISORIES ISSUED EARLIER IN TACT. LES IS OFF AND RUNNING WITH GENERAL WIND PARALLEL BANDS SETTING UP. BAND OF LIGHT SNOW SHOWERS DROPPING ACROSS UPR MI ATTM...ASSOCIATED WITH ARCTIC FRONTAL BOUNDARY. TEMPS HAVE FALLEN OFF IN THE WAKE OF THE BOUNDARY INTO THE TEENS...AND AS LOW AS 10 ABOVE AT KCMX. SNOW SHOWERS TO THIS POINT ON TAME SIDE PER SPOTTER REPORTS AND VARIOUS WEBCAMS. EXPECT INTENSITY OF SHSN TO INCREASE THIS EVENING AS THERMAL TROUGH WITH H85 TEMPS LOW AS -22C SWINGS ACROSS CWA. COMBINATION OF ARCTIC AIRMASS TRAVELLING OVER WARMER LAKE SUPERIOR AND SHORTWAVE DROPPING ACROSS WRN LK SHOULD VEER 925-850MB WINDS TO AT LEAST NNW (ALREADY OCCURRING OVER NRN LK SUPERIOR). 12Z WORKSTATION ETA/LATEST RUC SHOWING N WIND AT SFC FM 03Z-09Z. THIS WIND DIRECTION FAVORS GOG/ONT AND ERN MARQUETTE/WRN ALGER FOR SEEING BEST CHANCES OF DOMINANT CONVERGENCE BAND...WITH AMOUNTS OF POSSIBLY 1"/HR. MAIN LIMITING FACTOR IS LACK OF SYNOPTIC MOISTURE BEHIND ARCTIC FRONT (12Z CWPL SOUNDING SHOWING MOIST LAYER AROUND H85...WITH DRY AIR ABOVE). THIS IS ESPECIALLY THE CASE FOR FAR WRN ZONES. EVEN SO...ONGOING LES LOOKING HEALTHY WITHOUT MUCH SYNOPTIC MOISTENING AND ETA FCST SOUNDINGS SHOWING MOIST LAYER TO H85 BY 00Z SUGGESTING THAT LOWER LEVEL CONVERGENCE AND SUFFICIENT DLT T/S (20-23C) SEEMS TO BE OVERCOMIMG LACK OF BACKGROUND MOISTURE. PERIOD OF HEAVIEST SNOW LOOKS TO BE FM 02Z-08Z...BUT MOD SNOW IS POSSIBLE EITHER SIDE OF THAT WINDOW. KEPT ACCUMS IN LINE WITH UPDATE...ALTHOUGH LATEST WORKSTATION ETA QPF WOULD YIELD NEAR WARNING CRITERIA SNOW OVR FAR ERN MQT COUNTY WITH SNOW-WATER RATIO OF 50:1. N WINDS IN BLYR 20-25KT WILL PRODUCE BLSN IN OPEN AREAS EARLY TONIGHT WITH STRONG CAD...BUT LACK OF GRADIANT OVR NRN LAKE AND WARMING LATE AT H9-H85 WILL ALLOW BLSN TO DIMINISH OVERNIGHT. TEMPS ARE ALREADY PLUNGING AND SHOULD FALL TO AROUND ZERO ALONG WI BORDER AND HOVER IN THE SINGLE DIGITS ELSEWHERE. TEMPS MIGHT REMAIN IN THE LOWER TEENS NEAR LK SUPERIOR SHORE WITH ONSHORE WIND. JLA ...LONG TERM (FRIDAY THROUGH THURSDAY)... 12Z MODELS SHOW UPR RDGING IN WAKE OF SHRTWV RESPONSIBLE FOR TNGT'S LES DOMINATING CWA ON FRI. ALTHOUGH THERE WL BE SOME LINGERING LES OVR THE KEWEENAW AND THE ERN ZNS IN THE MRNG...INVRN HGT LWRG BLO 3K FT/QUICKLY RISING H85 TEMPS AS WELL AS DRY AIR WL LIMIT INTENSITY OF PCPN. ONCE WND SHIFTS MORE SW DURG DAY WITH PASSAGE OF SFC-H85 RDG AXIS...XPCT ALL ACTIVITY TO END AS UNMODIFIED DRY AIR UPSTREAM ADVCTS INTO CWA. SCNTRL ZNS SHUD SEE MOSUNNY DAY. MIXING UP TO H925 ON FCST ETA SDNGS SUG A COMPROMISE BTWN HIER ETA/LWR NGM MOS FCST TEMPS IN ORDER...WITH MIDDLE OF THE ROAD AVN MOS GUIDANCE A GOOD CHOICE. 12Z GFS/ETA/CNDN MODELS SHOW SHRTWV NOW TOPPING RDG IN NW TERRITORIES APRCHG CWA LATE FRI NGT...A BIT FASTER THEN EARLIER RUNS. SO HAVE ADDED CHC POPS TO W CWA LATE FRI NGT AS ALL THREE OF THESE MODELS PAINT QPF THERE BY 12Z. LACK OF ISENTROPIC LIFT AHD OF SHRTWV SUGS SKIES WL BE MOCLR UNTIL ASSOCIATED DPVA/H85-5 QVECTOR CNVGC ARRIVE JUST BEFORE FCST ONSET OF PCPN. DESPITE PD OF MOCLR SKIES AND DRY AIR (PWAT BLO 0.10 INCH)...FCST TIGHT PRES GRADIENT BTWN DEPARTING SFC RDG AXIS AND INCOMING CLIPPER SUGS HIER AVN MOS GUIDANCE TEMPS MOST RSNBL. ALTHOUGH ETA SHOWS LLVL WSW WNDS AS HI AS 45KT AT 2K FT AGL...HI STABILITY WL PREVENT MIXING OF THIS MOMENTUM TO SFC. GOOD AGREEMENT INDICATING SHRTWV WL DIG SHARPLY SE WITH BEST DPVA/H85-5 QVECTOR CNVGC AND THICKEST BAND OF HIER H85-5 RH PASSING S OF CWA. TRACK OF BEST DYNAMICS TO S...LACK OF CLOSED LO CENTER AND WAD/ISENTROPIC LIFT... AS WELL AS LIMITED MSTR (H7 SPECIFIC HUMIDITY ONLY ARND 1G/KG) SUG A WDSPRD BUT LGT QPF EVENT ON SAT AS SYS SHIFTS W TO E ACRS CWA. DYNAMICS EXIT WRN ZNS DURG SAT AFTN...BUT CYC NNELY FLOW AND H85 THERMAL TROF WITH TEMPS -18C TO -20C LINGERING BEHIND SFC LO WL CAUSE PCPN TO HANG ON INTO SAT EVNG. 12Z GFS/ETA IN GOOD AGREEMENT ON TIMING OF CLIPPER SYS TO IMPACT CWA ON SUN...AND NOW SHOW THIS SYS AS FAIRLY POTENT WITH GFS FCSTG CWA IN LEFT EXIT OF 140KT H3 JET MAX ON SUN. BOTH MODELS NOW ADVERTISE A PD SAT NGT INTO SUN WHEN RDG AXIS BTWN DEPARTING SAT SYS AND INCOMING SUN CLIPPER DOMINATES...SO HAVE DEPICTED A BRK IN PCPN BTWN THE TWO SYS DURG THIS PD. PARTIAL CLRG OVR SCNTRL ZNS SAT NGT WL ALLOW TEMPS TO FALL MORE SHARPLY THERE. PCPN WL RETURN ON SUN W-E AS LEFT EXIT OF JET/INCRSG MID LVL RH/AXIS OF H85-5 QVECTOR CNVGC MOVE INTO CWA. HOWEVER... LACK OF STRG WAD/ISENTROPIC LIFT...LIMITED MSTR (H7 SPECIFIC HUMIDITY ONLY ABOUT 1G/KG)...AND TRACK OF MAIN SFC LO OVR CWA OR JUST TO THE N (TO LIMIT LK ENHANCEMENT) AGAIN SUG A WDSPRD BUT LGT QPF EVENT. SO LIKELY POPS W TO E OVR ENTIRE CWA. SW FLOW AHD OF SFC LO SUGS PSBL LK ENHANCEMENT OFF LK MI E OF ISQ PER ETA FCST WITH H85 TEMPS NOT MUCH HIER THAN -15C... BUT GFS SOLN INDICATES LLVL WND WL HAVE TOO MUCH OF A W COMPONENT TO OPTIMIZE FETCH FOR SCHOOLCRAFT COUNTY. 00Z EXTENDED MODELS CONT TREND OF DEEPENING UPR TROF IN ERN NAMERICA AND ALLOWING VERY COLD ARCTIC AIR TO SPILL S INTO THE UPR GRT LKS IN WAKE OF ANOTHER CLIPPER TYPE SHRTWV ON MON. HOWEVER...SOME DIFFERENCES SHOW UP IN OPERATIONAL MODEL SOLNS THAT WOULD IMPACT FCST. OPERATIONAL GFS HAS BACKED AWAY A BIT FM DIRECT PLUNGE OF ARCTIC AIR ADVERTISED YDAY FOR TUE/WED... SHOWING CORE OF COLD AIR (I.E. H85 TEMPS BLO -30C) STAYING IN ONTARIO. SINCE ECMWF/UKMET/CNDN MODELS AS WELL AS MAJORITY OF GFS ENSEMBLE MEMBERS SHOW MORE OF A DIRECT SHOT OF ARCTIC AIR INVADING THE GRT LKS...WL STICK WITH THE GOING COLDER SCENARIO AND FCST TEMPS LWR THAN GFS MOS GUIDANCE ON TUE/WED. GFS ENSEMBLE MEAN SHOWS H100-5 THKNS 490-498 DM ON TUE... AND 12Z GFS SUPPORTS COLDER SOLN WITH H85 TEMP AOB -30C OVR MOST OF CWA. SINCE OPERATIONAL GFS ALSO AN OUTLIER SHOWING COLDER AIR EASING THE MIDDLE OF NXT WEEK WITH MORE OF A WLY FLOW ALF ALLOWING SOME OVRRNG PCPN BY THU...WL GO LWR THAN GFS MOS TEMPS AND LWR POPS FOR THU. KC COORDINATED WITH APX. .MQT...HVY FRZG SPRAY WRNG LK SUP. ...GALE WRNG W 1/2 LK SUP. ...LES ADVY TNGT MIZ002-005-006-007-009-085. mi