NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 303 PM MST TUE JAN 18 2000 SHORT TERM DISCUSSION: CURRENT RADAR AND SATELLITE DATA SHOWING ANOTHER CHUNK OF ENERGY MOVING UP AND OVER THE UPPER RIDGE AXIS RIGHT INTO THE FORECAST AREA NOW. THE AREA PROFILERS AND RUC GRIDS ARE SHOWING A JET IN THE VICINITY AND SOME OF THE RADAR RETURNS APPEAR BANDED. REPORTS IN THE HIGH MOUNTAINS ALSO INDICATE THE WEST-SOUTHWESTERLY WINDS IN INCREASING NOW. RADAR DOES SHOW DECENT COVERAGE BUT MOST OF IT IS VIRGA OVER THE PLAINS...WITH JUST A FEW SPRINKLES. VERY LIGHT SNOW IN THE MOUNTAINS. CROSS SECTIONS SHOW CSI AROUND THROUGH THE ENTIRE FIRST PERIOD...WITH THE JET IN THE VICINITY...AND WEAK Q-G ASCENT TOO. THERE IS ALSO DECENT CONVECTIVE INSTABILITY ALL NIGHT AND STEEPER LAPSE RATES THEN AS OF LATE. STILL PRETTY WARM ALOFT THOUGH...AND THE WIND DIRECTION FOR GOOD OROGRAPHIC SNOWFALL IS NOT GREAT. WILL GO "LIKELY"S IN THE MOUNTAINS TONIGHT. CONSIDERING SNOW MODEL AND ABOVE INFORMATION...5 INCHES AT MOST IS POSSIBLE IN A FEW AREAS. SATELLITE PICTURES SHOW A BACK EDGE TO THE BEST MOISTURE AND MOISTURE GRIDS CONCUR... CLOUDINESS TO DECREASE GRADUALLY BY DAWN. LOW LEVEL SURFACE AND PRESSURE GRIDS SHOW TROUGH MOVING EASTWARD THIS EVENING OUT OF THE STATE BY MIDNIGHT KILLING THE DECENT SOUTHEAST FLOW. FOR THE PLAINS..."SCATTERED" LIGHT RAIN/SNOW SHOWERS LOOK OK OVER THE BEST MOISTURE FETCH/JET PROXIMITY AREAS (NORTHERN AND EASTERN BORDER ZONES)..."ISOLATED" REST OF PLAINS. TEMPERATURE/THICKNESS GRIDS SHOW LITTLE CHANGE IN LOWS TONIGHT FROM THIS MORNING'S LOWS. RJK LONG TERM DISCUSSION: UPR LV TROF WL CONT OVR ERN US AND OFF WRN US COAST THRU THU AS UPR LVL RDG REMAINS OVR GREAT BASIN. ON WED APPEARS QUITE A BIT OF MID-LVL DRYING WL OCCUR AS LARGE BATCH OF SUBTROPICAL MSTR MOVES EAST OF RGN ACCORDING TO CROSS-SECTIONS. QG FIELDS SHOW BASIC DESCENT ACRS RGN WITH POOR LAPSE RATES AND WRM MID-LVL TEMPS. THUS PCPN CHCS LOOK LOW EXCEPT FOR SOME WDLY SCT -SHSN OVR THE MTNS. LATEST CROSS-SECTIONS SHOW SOME POTENTIAL FOR HI WNDS EARLY WED MRNG IN THE HIGHER FOOTHILLS AS COMPONENT ALONG WNDS INCR TO 50KTS. OVER NERN CO MAIN CONCERN WL BE TIMING OF CDFNT INTO RGN. COULD SEE FNT MOVE INTO EXTREME NERN CO BY AFTN AND THEN BACKDOOR INTO FNT RANGE BY WED EVENING. AS A RESULT TEMPS FCSTS FOR WED AFTN WL BE TRICKY AS READINGS MAY TOP OUT BY MIDDAY IN THE NERN CORNER. FOR WED NGT AND THU COLD SFC HI PRES WL BUILD INTO NRN AND CNTRL PLAINS. THERE IS A BIG DISAGREEMENT IN THE MODELS REGARDING SFC POSITIONS AND PRESSURES BY 12Z THU. NGM AND AVN SHOW LEE TROF DVLP BY 12Z THU WITH LOW LVL FLOW BECOMING WLY OVR NERN CO AS SFC LOW PRES DVLPS OVR WY. MEANWHILE ETA HAS MUCH HIGHER SFC PRESSURES WITH LOW LVL FLOW MORE SELY. AT THIS TIME BELIEVE SHALLOW COLD AIRMASS WL REMAIN OVR NERN CO AND WL DISREGARD TEMP GUIDANCE FM FWC. BIG QUESTION IS WHETHER COLD AIR WL MAKE IT INTO THE FOOTHILLS. TEMPS IN THE FOOTHILLS COULD RANGE FROM THE 20S AND 30S TO THE 40S AND 50S. AS FAR AS PCPN GOES IF UPSLOPE IS STRONGER THAN FCST COULD SEE SOME LIGHT PCPN DVLP OVR NERN CO WED NGT AND THU. CROSS-SECTIONS DO SHOW SOME POTENTIAL FOR CONDITIONAL SYMMETRIC INSTABILITY (CSI) IF DEPTH OF MSTR IS SUFFICENT. IN THE MTNS COULD SEE SOME INCR IN SHSN ACTIVITY WED NGT AND THU AS OROGRAPHIC FLOW BECOMES MORE WNW. AVN AND ETA SHOW SOME MID-LVL CAA OVERNIGHT AND WITH UPR LVL JET IN PLACE PCPN COULD BE ENHANCED BY CSI. IN EXTENDED PD CLOSED UPR LVL LOW OFF WRN US COAST WL MOVE EAST AND SHEAR APART AS IT MOVES ACRS THE ROCKIES ON FRI. LAST NGT'S MRF SHOW SFC LOW OVR SERN WY ON FRI WITH DOWNSLOPE FLOW OVR NERN CO THUS TEMPS WOULD MDT SOME WITH LITTLE CHC FOR SNOW. HOWEVER KNOWING MRF'S BIAS FOR DVLPG SFC LOWS TO FAR N WL LEAVE FCST FOR FRI ALONE. IN THE MTNS STILL LOOKS LIKE A GOOD SHOT FOR SNOW AS ABV MENTIONED SYS MOVES ACRS RGN. FOR SAT AND SUN UPR LVL RDG WL REBUILD ACRS RGN WITH HI PRES AT THE SFC. THUS WL GO WITH A DRY FCST WITH SEASONAL TEMPS. KLEYLA DEN...NONE. co AREA FORECAST DISCUSSION...CORRECTED ADVSY SECTION NATIONAL WEATHER SERVICE TALLAHASSEE FL 300 PM EST TUE JAN 18 2000 FORECAST CHALLENGE -- PRECIPITATION CHANCES THROUGH THE PERIOD. CURRENTLY -- WATER VAPOR IMAGES SHOW MEAN RIDGE HOLDING ITS POSITION OVER THE W-CENTRAL USA BETWEEN AN UPPER LOW OVER THE ERN PACIFIC AND A BROAD TROUGH OVER THE WRN ATLANTIC. A MINOR SHORTWAVE TROUGH IS DIVING SE FROM THE OH VALLEY. AN AREA OF SUBSIDENCE HAS SPREAD OVER OUR CWA IN THE WAKE OF ANOTHER SE MOVING SHORTWAVE TROUGH. LOCAL MORNING SOUNDINGS SHOW ASSOCIATED SUBSIDENT LAYER AROUND 700 MB AND OTHERWISE MOIST ADIABATIC TEMPERATURE PROFILES. STRONG WLY FLOW HAS MIXED TO THE SURFACE OVER OUR CWA WITH DAYTIME INSOLATION. FRONTOGENETIC FORCING IS OCCURRING ALONG A SURFACE BOUNDARY EXTENDING FROM SC THROUGH NRN GA DUE TO BOTH DIFFERENTIAL HEATING (LOW CLOUDS ARE N OF THE BOUNDARY) AND SURFACE WIND CONFLUENCE ALONG THE FRONT. RECENT RADAR AND SATELLITE TRENDS INDICATE LIGHT PRECIPITATION HAS BEGUN TO FALL S OF THIS BOUNDARY IN ASCENDING BRANCH OF RESULTING DIRECT CIRCULATION. THE MORNING SOUNDING AT KCHS INDICATES A COLD AND SHALLOW AIRMASS WITH IMPRESSIVE ISENTROPIC LIFT N OF THE SURFACE FRONT OVER THE FRONTAL INVERSION. --FORECAST-- TONIGHT-- VISIBLE SATELLITE IMAGES AND RUC FORECAST SOUNDINGS SUGGEST MOSTLY CLOUDY SKIES WILL SPREAD OVER THE CWA. MODELS AGREE ON PUSHING FRONT S THROUGH CWA OVERNIGHT WITH NGM THE FASTEST AND MOST AGGRESSIVE. SOME PRECIP IS GENERATED BY MODELS ALONG THIS BOUNDARY AS IT MOVES S...ALTHOUGH NEITHER FORECAST SOUNDINGS NOR ISENTROPIC SURFACES SUGGEST DEEP LIFTING. WILL AT LEAST KEEP SLIGHT CHANCE POPS ALREADY MENTIONED. WEDNESDAY-- FORECAST SOUNDINGS AND ISENTROPIC SURFACES BOTH BEGIN TO SUGGEST DEEPER LIFT OVER THE CWA WITH HIGHEST DEEP LAYER RH VALUES OVER THE NRN CWA. ELY FLOW OVER THE CWA BEHIND THE FRONT WILL RAPIDLY VEER TO THE S BY EVENING AHEAD OF NEXT APPROACHING SYSTEM. WEDNESDAY NIGHT-- SHORTWAVE TROUGH OVER SW CANADA WILL DIVE SE TO OH VALLEY BY THURSDAY MORNING...WHICH WILL DRAG AN AREA OF LOW PRESSURE AHEAD OF IT. OVER THE CWA FLOW WILL BECOME WLY AHEAD OF APPROACHING FRONT THAT WILL BE STRETCHED SW OVER AL. A CHANCE OF RAIN WILL BE JUSTIFIED...AND WILL TRY TO BLEND POPS WITH ATL...WHOSE CWA SHOULD OVERALL SEE BETTER POPS. THURSDAY-- WILL BE QUITE COOL AND WINDY IN WAKE OF COLD FRONT. WILL NOT DEVIATE FAR FROM RUC/AVN GUIDANCE. MAY INCLUDE LEFTOVER POPS FOR BEGINNING OF PERIOD FOR WRN ZONES. FIRE WEATHER - QUITE GUSTY WINDS THIS AFTERNOON FORTUNATELY ACCOMPANIED BY HIGHER RH VALUES. NO HIGHLIGHTS EXPECTED. MARINE - JUST UPDATED CWF FOR SCA NEARSHORE WATERS BASED ON REPORTED HIGH WIND GUSTS. WILL KEEP SCEC FOR OUTER WATERS. PROSPECTS LOOK GOOD FOR SCA THURSDAY IN WAKE OF COLD FRONT. EXTENDED -- (THURSDAY NIGHT THROUGH SUNDAY) MRF ADVERTISES MOSTLY CLEAR CONDITIONS THROUGH SATURDAY AS HIGH PRESSURE BUILDS OVER AREA WITH PERSISTENT OFFSHORE FLOW. UPPER FLOW TO BECOME MORE ZONAL THROUGH PERIOD RESULTING IN GRADUAL WARMUP. RETURN FLOW EXPECTED BY SUNDAY AHEAD OF NEXT FAST-MOVING DISTURBANCE IN ZONAL FLOW. THANKS TO ATL FOR COORDINATION. OTHER INPUT IS WELCOME. PRELIMINARY NUMBERS... TLH 051/066 050/067 2441 PFN 054/060 054/066 2441 DHN 050/058 048/065 243- ABY 048/062 048/062 2342 VLD 050/061 049/067 2342 .TLH... AL...NONE. GA...NONE. FL...SCA SUWANNEE RIVER-DESTIN OUT TO 20 NM THIS EVENING. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 1115 AM CST TUE JAN 18 2000 VIS SATELLITE SHOWS A BREAK IN THE CLOUDS OVER THE KC METRO EDGING WEST INTO MOST OF ATCHISON/JEFFERSON COUNTIES. THIS TREND IS BEING HANDLED WELL BY THE RUC MODEL...AND BELIEVE THAT THE LOW CLOUDS AND FOG WILL CONTINUE TO LIFT THROUGH THE AFTERNOON. MID-LEVEL CLOUD COVERAGE OVER SOUTHEAST NEBRASKA ALSO APPEARS TO BE LESSENING...FOR THE MOST PART... AS IT MOVES SOUTHEASTWARD. WILL UPDATE ZONES SHORTLY AND PLAN ON USING PARTLY SUNNY WORDING OVER NORTH-CENTRAL KANSAS AND BECOMING PARTLY SUNNY OVER MUCH OF NORTHEAST AND EAST-CENTRAL KANSAS. MAY KEEP SOME THICKER CLOUD COVER OVER THE SOUTHEAST ZONES AND DO SOME RECONFIGURING OF GROUPINGS. WILL ALSO TAKE A GOOD LOOK AT TEMPERATURES BEFORE RELEASE TIME. 65/63 .TOP...NONE. ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 900 PM CST TUE JAN 18 2000 A WEAK FRONTAL BOUNDARY THIS EVENING EXTENDED WEST TO EAST ACROSS THE COUNTY WARNING/FORECAST AREA ALONG/JUST SOUTH OF A TYR TO SHV...MLU TO TVR LINE. THE FRONT IS ALMOST STATIONARY AND WILL SLIP SLIGHTLY SOUTH...STALLING...AND THEN RETREATING NORTHEAST DURING THE MORNING WEDNESDAY. LOOKING AT THE LATEST RUC MODEL DATA WILL UPDATE SOME OF THE ZONES AND LOWER TEMPERATURES AND MAKE A FEW WIND ADJUSTMENTS. WILL ALSO MENTION PATCHY FOG IN THOSE ZONES OVER THE NORTH TO THE BACK SIDE OF THE FRONTAL BOUNDARY. THE FOG MAY BE DENSE IN SOME AREAS BUT WILL HANDLE WITH NOWCASTS UNLESS FOG BECOME MORE WIDESPREAD AT WHICH TIME A DENSE FOG ADVISORY WOULD BE CONSIDERED. 06 .SHV...NONE. la AREA FORECAST DISCUSSION ...CORRECTED... NATIONAL WEATHER SERVICE CARIBOU ME 936 PM EST TUE JAN 18 2000 SYNOPSIS: LOW PRESSURE EAST OF NOVA SCOTIA WILL CONTINUE MOVING AWAY AS HIGH PRESSURE GRADUALLY RIDGES INTO THE REGION TONIGHT AND WEDNESDAY. HIGH PRESSURE WILL REMAIN IN CONTROL WEDNESDAY NIGHT... LOW PRESSURE WILL FORM ALONG THE MID ATLANTIC COAST ON THURSDAY. TECHNICAL DISCUSSION: MAIN FOCUS OVNGT IS LOW TEMPS. CRNT MTRS SHOWING TEMPS/DWPTS MUCH LOWER THAN WHAT GUID WAS ADVERTISING. GOING AWAY FM GUID ON MINS LOOKS THE WAY TO GO. THE ONLY ICEBALL IN TNGT/S FCST WOULD BE THE SCT SCU SKIRTING FAR NRN ME...MAINLY NE AROOSTOOK COUNTY PER LATEST SATL IR IMAGERY. STILL FEELING EFFECTS OF CLOSED LOW IN THE MARITIMES. THIS SYSM SHOULD PULL AWAY. 00Z CAR RAOB HAD SOME DECENT RH @ H8. 00Z RUC KEPT RH IN TIL 06Z. WIND FIELD BECMG MORE NWLY IN THE COLUMN AFT 06Z SHOULD HELP TO DRY THGS SOME BY WED MRNG. FOR TEMPS/WINDS...WILL KEEP THGS WHR THEY ARE AS GUID HAS BEEN RUNNING TOO LOW THE PAST FEW DAYS. WINDS STILL NAR 10 MPH BUT SHOWING SIGNS OF DECG. COASTAL WATERS: PRVS PKG IN GOOD SHAPE. CAN/T SEE ANY SIGNIFICANT REASON TO CHG THGS AS MIGNONE HAS THGS IN HAND. .CAR...NONE. JAH me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1000 PM EST TUE JAN 18 2000 CURRENT REGIONAL ANALYSIS SHOWS BROAD AREA OF LOW PRESSURE OVER EASTERN UPPER MI TO NORTH OF EASTERN LAKE SUPERIOR. DEEPER WRAP-AROUND MOISTURE HAS COMBINED WITH DECENT OVER-WATER INSTABILITY (LAKE-850 MB DELTA T'S AROUND 17C) TO PRODUCE A WIDESPREAD AREA OF LAKE-ENHANCED SNOW SHOWERS. KAPX 00Z SOUNDING SHOWS PLENTY OF MOISTURE WITHIN THE -12 TO -15C ISOTHERMS (OPTIMAL FOR SNOW DENDRITIC GROWTH)...SO AGAIN WE ARE SEEING FAIRLY LARGE SNOWFLAKES. THIS ALONG WITH A 20 TO 1 SNOW-WATER RATIO IS AGAIN ALLOWING THE SNOW TO PILE UP RATHER WELL. 00Z RUC AND 18Z MESO-ETA CONSISTENT WITH EARLIER 12Z PROGS. Q-VECTORS DIVERGE FROM W TO E OVERNIGHT AS INCREASING DNVA/UPPER CONVERGENCE ALLOW FOR DECENT SUBSIDENCE/DRYING WITH THE SYSTEM PULLING OFF TO THE EAST. MODEL SOUNDINGS FOLLOW SUIT WITH 850-600 MB MOISTURE DIMINISHING AND INVERSIONS DROPPING TO 850 MB BY DAYBREAK. LAKE-850 MB DELTA T'S AROUND 17C IN ERN LAKE SUPERIOR AND 15C/16C OVER NRN LWR ARE ONLY MARGINAL FOR PURE LAKE EFFECT (W/O SYNOPTIC ENHANCEMENT)...THUS CONTINUE TO EXPECT SNOW SHOWERS TO DIMINISH IN INTENSITY AND AREAL COVERAGE. PRIOR FORECAST HAD WORDED ACCUMS TONIGHT WITH THE EXPECTATION THAT THE BULK WOULD FALL IN THE EVENING (WHICH IT HAS)...THEREFORE WITH THE UPDATED FORECAST WILL MENTION LIGHT ADDITIONAL AMOUNTS. CURRENT TEMP FORECAST STILL LOOKS REASONABLE...AS TEMPS SHOULD BEGIN TO DROP MORE APPRECIABLY LATER TONIGHT WITH THE COLD ADVECTION. HIGHER WIND SPEEDS/LAKE EFFECT CLOUD COVER WILL ALLOW FOR SOME INSULATION AND (THUS) PREVENT WIDESPREAD READINGS BELOW 10F. .APX...NONE. HURLEY mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1045 AM EST TUE JAN 18 2000 INTENSITY AND AREAL COVERAGE OF SNOW ARE AGAIN INCREASING WITH THE APPROACH OF A SHORT WAVE DROPPING SE OUT OF ONTARIO LATE THIS MORNING. UPSTREAM AND LOCAL RADARS CLEARLY SHOW AN ENHANCED AREA OF 28+ DBZ WORKING ITS WAY SE TOWARD ERN UPR MI. LOCATION OF THIS AREA OF MODERATE TO HEAVY SNOW IS MATCHING WELL WITH ETA AND LATEST RUC SOLUTION...PIN-POINTING THE GREATEST AREA OF DPVA AND 850-700 MB Q-VECTOR CONVERGENCE OVER CENTRAL UPR MI ATTM. GREATEST UPPER SUPPORT SLIDES SE THROUGH ERN UPR MI AND FAR NRN/NE LOWER MI THIS AFTERNOON. WEAK ISENTROPIC ASCENT WILL ALSO LEND SOME SUPPORT TO SNOW OVER THESE AREAS THROUGH THE AFTERNOON...BUT MIXING RATIOS ARE AROUND 1 G/KG OR SO. THUS...ADDITIONAL ACCUMULATIONS WILL BE LIMITED TO 2 TO 3 INCHES FOR ERN UPR MI AND 1 TO 3 ACROSS FAR NRN AND NE LOWER MI ZONES. WILL ALSO HAVE TO INTRODUCE CATEGORICAL POPS FOR SE SECTIONS OF THE CWA AROUND GLADWIN AND OSC BASED ON LATEST RUC PROJECTIONS OF VORT TRACK AND CURRENT RADAR TRENDS...BUT WILL LIMIT ACCUMULATIONS TO AROUND AN INCH. DRIER MID LEVEL AIR AND LACK OF UPPER FORCING AS THE SHORT WAVE SLIDES E OF THE AREA WILL PRECLUDE SIGNIFICANT SNOW IN LOCATIONS W OF TVC TO HTL. WILL WORD AS SCT SHSN FOR THE AFTERNOON. HOWEVER...LACK OF MID LEVEL MOISTURE AND AMPLE LOW LEVEL MOISTURE WILL CONTINUE TO PRODUCE PATCHY FREEZING DRIZZLE IN THESE LOCATIONS AS WELL. WILL WORDING ACCORDINGLY. TEMPS HAVE BEEN SLOW TO WARM SO FAR...BUT UPSTREAM TEMPS HAVE WARMED NICELY INTO THE LOW TO MID 20S OVER WI WITH WAA. WILL KEEP HIGH TEMPS IN THE LOW TO MID 20S FOR THE AFTERNOON IN ANTICIPATION OF INCREASING WAA AHEAD OF THE COLD FRONT. WILL ALSO HAVE TO ADJUST WORDING OF WIND FORECAST TO ACCOUNT FOR LATEST TRENDS. .APX...NONE. EME mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 915 PM CST TUE JAN 18 2000 COLD AIR ADVECTION WEAKENING A LITTLE IN ADVANCE OF MID-UPPER LEVEL SHORTWAVE THAT WILL APPROACH LOWER MS VALLEY REGION FROM NW TX BY 09-12Z. LAMP SURFACE DEWPOINT PROGS REMAIN ABOVE 50 ALONG AND S OF I-20 THROUGH EARLY WEDNESDAY WHILE VERY SHALLOW DRYING TAKES PLACE ALONG AND N OF A BASTROP...LA TO KNMM LINE. SURFACE TO 850MB MOISTURE CONVERGENCE BEST IN THE 06Z-18Z TIME WINDOW WHEN MESO-ETA AND RUC KEEP MEAN RELATIVE HUMIDITIES 75-80% ALONG THE DRYING AXIS. AFTER 18Z...BAND OF MOISTURE ALONG THE FRONT LIFTS NEWD INTO THE TN VALLEY PUTTING MOST OF CWA IN WARM SECTOR THROUGH WEDNESDAY EVENING. ONLY MINOR CHANGES TO FORECAST TO RAISE OVERNIGHT MINIMUMS AND TWEEK WORDING IN A FEW PLACES OTHERWISE PACKAGE IN GREAT SHAPE. JAN 50/65/47/62 5320 MEI 49/64/47/63 5320 .JAN... MS...NONE. AR...NONE. LA...NONE. ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1025 PM CST TUE JAN 18 2000 STRONG WAA AND ISENTROPIC LIFT WILL GENERATE INCREASING CHANCE FOR PRECIPITATION THE REST OF TONIGHT INTO AT LEAST WEDNESDAY MORNING AS DVLPG SFC LOW NERN WY MOVES ESEWD. FCST PROBLEMS WITH PRECIP CONCERN SATURATING ATMOSPHEREIC COLUMN THAT IS INITIALLY DRY AT LOW LEVELS IN ERN NEB AND SW IA FOR PRECIP TO REACH GND. SECOND CONCERN CENTERS ON PRECIP TYPE. SOUNDINGS GENLY WARM ENUF TO SUPPORT LIQUID PRECIP WHICH CUD BE IN FORM OF FREEZING PRECIP AT GND IN AREAS BASED ON SFC TEMPS. HOWEVER BIQ QUESTION IS HOW FAST LWR LEVELS WILL SATURDATE. IF THIS IS TOO SLOW EAVAPORATIVE COOLING TO WET BULB TEMP BELOW MOIST MID LEVELS CUD CHANGE PRECIP TO SNOW. THIS PROCESS BEING ABETTED THOUGH THROUGH THE NIGHT BY LWR LVL WAA. FOR NOW AFTER COORD CALL KFSD BASED ON TRENDS OF LATEST RUC AND QUICK LOOK ATN NEW ETA...APPEARS PTNS NE NEB INTO W CNTRL IA MST AT RISKFRO PRBLMS AND HAVE ISSUED WSW THIS SECTION. .OMA...WINTER WEATHER ADVISORY...TNGT AND WED MRNG...NEZ011-012- WIESE ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 905 PM EST TUE JAN 18 2000 00Z GSO SOUNDING SHOWS A SFC TO 5KFT SATURATED AIRMASS TRAPPED BELOW AN INVERSION EAST OF THE MTNS. I HAVE SEEN NO EASTWARD EROSION OF THIS CLOUD LAYER SINCE 4 PM. MSAS SHOWS PERSISTANT LOW PRESSURE ACROSS THE FOOTHILLS WHICH THE RUC KEEPS STATIONARY OVERNIGHT. SO I EXPECT THE CLOUDS AND FOG TO PERSIST FOR MUCH IF NOT ALL OF THE NIGHT. FOG STILL DENSE IN MANY PLACES ACROSS THE CURRENT ADVISORY AREA. THIS LEE TROUGH IS CONTRIBUTING TO A TIGHT PRESSURE GRADIENT ACROSS THE MTNS AND RESULTING IN WINDY CONDITIONS. WILL NEED TO UP THE WINDS IN THE MTNS TO ACCOUNT FOR THIS AND ANY MIXING DOWN OF 30+ KT 850 MB WINDS. TEMPS ARE THE OTHER CONCERN. AIRMASS TO THE WEST ACROSS GA IS WARMER AND WE'VE ACTUALLY SEEN TEMPS RISE A LITTLE OVER THE PAST FEW HOURS ACROSS THE UPSTATE AND FOOT/PIED OF NC. TEMPS IN THE MTNS MAY COOL TO PROJECTED LOWS AS AIRMASS UNDER HIGH IN SRN IL BUILDS EAST. HOWEVER...UNDER THICK CLOUDS AND FOG...EAST OF THE MTNS...TEMPS WILL BE HARD PRESSED TO FALL AT ALL. WILL ADJUST ZONES ACCORDINGLY. .GSP...DENSE FOG ADVISORY FOR NC FOOTHILLS/PIEDMONT (NCZ034>037-054>057-066>072-082) MOYER sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1019 AM EST TUE JAN 18 2000 LTST SFC ANALYSIS INDICATES FNTL BNDRY GETTING WAVY ACRS THE RGN... XTNDG JST E OF CHS THEN SW TO NBC...WNW TO N OF MCN THEN NW TWD ATL. LST GUD FIX ON LO WAS IN VCNTY OF NRN GA/SERN TN...THO ACTUAL POSN OF SFC LO NOW TUFF TO PICK OUT AS TRANSLATION TWD THE CST APPEARS TO BE OCCURING. WNDS ARE STARTNG TO BECOME CNTRCLOCKWISE JST E OF CHS...AND SFC TEMPS AT OGB/FLO/MYR HV ALL DECREASED IN THE PAST HR IN MORE NRLY FLO...AFT RISING FOR MOST OF THE NGT...WHILE FLO AT BUOY 41004 NOW SE. SHUD SEE SFC LO START TO APPEAR JST TO OUR E OVR NXT FEW HOURS. GUD SLUG OF MSTR ALNG AND N OF MCN TO NBC LINE HDNG SE ACRS CWA. WL NEED TO KP POPS UP THRU THE AFTN MOST FOR AREAS N OF SAV RVR...AND RAISE A LTL S OF SAV RVR. AS SFC LO DVLPS OFF THE CST THS AFTN...NE FLO ARND IT WL THROW SOME MSTR FM THE ATLNTC BACK ACRS THE AREA...AND CAUSE PCPN TO PERSIST INTO THE ERLY EVENING HOURS FOR MUCH OF THE RGN. DO NOT LIKE TO CHG 2ND PD OF FCST NORMALLY WITH MORNING UPDATE...BUT REALLY FEEL IT IS NECESSARY IN THIS CASE. WL ADD AT LST CHC POPS ALL CSTL AREAS WI WDLY SCT POPS WELL INLAND. BASED ON LTST RUC/MESOETA...WHICH SEEM TO HAVE GUD HANDLE ON SITN...DRIER AIR/SINKING MOTION REALLY DOES NOT GET ALL THE WAY THROUGH CWA UNTIL CDFNT PUSHES S OF SE GA LTR TNT. SO CLRNG SHUD STL OCCUR FM NW TO SE...BUT JST A LTL LATR THAN PREVSLY THOUGHT. CWF...WINDS OVER THE CSTL WATERS ARE ELY ACROSS THE N PTN AND S-SW ACROSS THE S. WINDS HV BEGUN TO INCREASE ACROSS GA WATERS AS EVIDENCED BY 41008. LOOKS LIKE 20 KT A GOOD BET THIS AFT ACROSS THE GA WATERS. WL RAISE FLAGS FOR THE NEAR SHORE WATERS. OVER THE SC WATERS...AS LOW PRES MOVES OFF THE CST THIS EVE AND INTENSIFIES...IT APPEARS AS THO SCA COND WL SET IN DURING THE EVE. WL THEREFORE RAISE FLAGS FOR THE SC WATERS THIS PKG. .CHS... SC...SMALL CRAFT ADVISORY SOUTH SANTEE RIVER TO SAVANNAH OUT 20 NM EXCLUDING THE CHS HARBOR. GA...SMALL CRAFT ADVISORY SAVANNAH TO ALTAMAHA SOUND OUT 60 NM. WOODWORTH/TJR sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1000 AM EST TUE JAN 18 2000 SO MUCH FOR MODEL QPF. THE MAIN CONCERN FOR THE MORNING UPDATE IS WHAT TO DO WITH THE WARNINGS/ADVISORIES THAT ARE CURRENTLY IN EFFECT. THE EVENT SEEMS TO BE WINDING DOWN SORT OF QUICKLY JUDGING BY KGSP RADAR...WHICH SHOWS MOST OF THE SIGNIFICANT PRECIPITATION MOVING OUT OF UPSTATE SC AT 1430Z. THE RADAR STILL SHOWS WIDELY SCATTERED PRECIP ELEMENTS ACROSS THE MOUNTAINS AND FOOTHILLS AND NO DOUBT THERE ARE AREAS OF FREEZING DRIZZLE ACROSS THE NC PIEDMONT...BUT AREA RADARS DO NOT SHOW ANY SIGNIFICANT PRECIP UPSTREAM. BOTH THE 06Z ETA AND THE 12Z RUC SHOW ALL THE LOW LEVEL FORCING FOR ADDITIONAL PRECIP ENDING IN THE 18Z TO 21Z TIME FRAME...EVEN THO THE 06Z ETA HOLDS ON TO SOME PRECIP THRU THE END OF THE DAY. WITH THAT IN MIND...DO NOT SEE MUCH OF A REASON TO HOLD ONTO THE WINTER WEATHER ADVISORIES ANY LONGER. WHILE THERE MAY BE SOME LINGERING FREEZING DRIZZLE IN THE WARNING AREA E OF THE MOUNTAINS... IT DOES NOT REALLY JUSTIFY HOLDING ONTO THE WARNING THERE AND WILL CANCEL IT. THE ONE AREA OF CONCERN MAY BE THE NORTHERN MOUNTAINS...WHERE VEERING LOW LEVEL FLOW WILL INTRODUCE MORE OF AN UPSLOPE COMPONENT AS THE DAY PROGRESSES AND 850 MB TEMPS MIGHT DIP SLIGHTLY. HOWEVER...MOISTURE IS ON THE WANE AND THE FORCING IS ALMOST ALL MECHANICAL. CALLS TO THE NORTHERN MOUNTAIN COUNTIES INDICATE THAT ANY PRECIP FALLING CURRENTLY IS LIQUID AND SURFACE TEMPS ARE ABOVE FREEZING. THUS...THE WARNING WILL BE CANCELLED THERE TOO. .GSP...NONE. MOORE sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 910 PM CST TUE JAN 18 2000 MAIN ISSUE UP FOR DEBATE TONIGHT IS WHETHER AN ADVISORY SHOULD BE HOISTED FOR SECOND PERIOD AT THIS TIME...FOR MAXIMUM REASONABLE LEAD TIME. COMPLICATING FACT IS THAT NO NEW DATA TO REALLY LOOK AT OUTSIDE RAOBS YET...AND THE DECISION HAS TO BE MADE NOW FOR MEDIA. EARLIER UPDATES WERE NECESSARY TO LOWER TEMPERATURES WHERE SKIES REMAIN CLEAR SKIES OR WITH ONLY THIN CI...WINDS LIGHT IN FLABBY GRADIENT...AND DEEP DRY AIR MASS. MAY ACTUALLY NOT HAVE LOWERED ENOUGH...BUT SHOULD SEE THINGS LEVEL OFF OR EVEN RISE WITH INCREASE IN CLOUDS AND SOUTHEAST WIND FLOW...WITH GENERAL WARMING OF LOWER ATM OVERNIGHT. ATTENTION THEN TURNS TO THE APPROACHING PCPN THREAT. IMPRESSIVE JET IMPULSE SLINGSHOTTING OUT OF EPAC CLOSED LOW NOW TOPPING FLAT WRN US RIDGE AND STARTING TO SHOW SIGNS OF UPCOMING PHASING WITH NRN STREAM TROUGH. FORTUNATELY...MY INTERPRETATION OF THE EVENTS ARE LARGELY CONSISTENT WITH THE AFTERNOON REASONING. IT APPEARS THAT THERE WILL BE SUFFICIENT TIME FOR NIGHT SHIFT TO POST ADVY WITH ENOUGH LEAD TIME CONSIDERING STRENGTH OF CURRENT FORECAST WORKDING. FOR MORE FAVORED ERN CWA FOR HEAVIER SNOWFALL. THE AREA OF SHORT TERM CONCERN IS THAT ALONG THE MO RVR LATER TONIGHT AND INTO WED MRNG. NEW ETA IN AND IN GENERAL AGREEMENT WITH RUC AT TARGETING THIS AREA FOR QPF LATE TONIGHT. FCST SOUNDINGS ARE INDICATIVE OF THE THREAT OF LIQUID STATE...BUT SOME CONCERN THAT TMPS MAY ACTUALLY RISE ABOVE FREEZING TO LIMIT ICING THREAT...AS SFC LOW IS FARTHER N AND TMPS MUCH WARMER THAN EXPECTED THIS EVENING IN NEBR INTO SCNTRL SD. HOWEVER...SOME EVAP COOLING LIKELY TO OCCUR AS WELL AND LIFT IS EXTREMELY IMPRESSIVE. MAY BE A BIT CONVECTIVE IN NATURE AS WELL. WL ISSUE A WINTER WX ADVISORY FOR MIXED PCPN THREAT... CHANGING TO ALL SNOW DURING THE MORNING. THAT WHICH WILL OCCUR FURTHER EAST WILL BE ISSUED WITH THE 4AM PACKAGE...BUT WILL LIKELY STRENGTHEN WORDING A BIT MORE IN THESE AREAS. WL HAVE TO WARM TMPS IN SWRN CWA AS WELL AS MENTION POSSIBILITY OF RAIN. COORD WITH MPX...DMX...OAX. .FSD...WINTER WX ADVISORY LATE TONIGHT AND WEDNESDAY MORNING MO RIVER CORRIDOR FM AROUND KYKN TO KSUX. CHAPMAN sd AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 755 PM MST TUE JAN 18 2000 ...MAIN FORECAST CONCERNS TONIGHT ARE WIND AND LIGHT PRECIP... AT 02Z A SURFACE COLD FRONT EXTENDED FROM CNTRL MT THROUGH FAR SWRN ND AND ACROSS NCNTRL SD. LOW PRESSURE WAS CENTERED EAST OF THE BIG HORNS WITH SURFACE PRESSURE FALLS OF 1-3 MB/3HR ACROSS THE ENTIRE CWFA. WATER VAPOR IMAGES SHOWED TWO SHORT-WAVE TROUGHS...ONE OVER SRN ALBERTA AND ANOTHER OVER ERN ID...THAT WERE MOVING TOWARD THE CWFA. MID-LEVEL CLOUDS WERE MOVING OVER MOST OF THE CWFA...WITH SOME LOWER CLOUDS AND LIGHT RAIN INVADING THE FAR SOUTHWEST. THE 00Z RUC HAD A GOOD HANDLE ON THE FRONT AND PROGS IT TO MOVE THROUGH ALL BUT SRN SD BY 12Z WED...WHILE THE SURFACE LOW MOVES TO SCNTRL-SERN SD. AS THE LOW AND FRONT MOVE THROUGH THE CWFA...THE WIND IS GOING TO BECOME NORTHWEST WITH STRONG (1-3 C/HR) COLD-AIR ADVECTION IN ITS WAKE. WITH A STRENGTHENING PRESSURE GRADIENT... EXPECT THE WINDS TO INCREASE LATER TNGT OVER NERN WY AND WRN-NCNTRL SD...AND WILL UPDATE FOR THIS. FINALLY...BASED ON SATELLITE AND RADAR DATA...EXPECT SCATTERED LIGHT PRECIP TO AFFECT MOST OF THE CWFA. BASED ON THICKNESS PROGS AND OBSERVATIONS...WILL MENTION POSSIBILITY OF RAIN OVER SRN CWFA. .UNR...NONE. BUNKERS sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 405 AM CST WED JAN 19 2000 ...LEAD SHRTWV AND PCPN AREA MOVING PRETTY QUICKLY EWD AND LATEST RUC DOWNPLAYS PCPN AND SNOW AMOUNTS OAX CWA. WE WILL NOW DROP WINTER WEATHER ADVSRY AND DECREASE SNOW AMOUNTS A LTL FM EARLIER WORK ZONES. WL NOT CHANGE THE REST OF THE AFD...EXCEPT HIGHLIGHT ...OF WHICH THE ORIGINAL RMNS BLO. WARM ADVCTN DEFINITELY WINNING THE BATTLE THIS MORNING AS TEMPS HAVE CLIMBED INTO THE UPR 30S WITH ONSET OF PCPN FM LNK TO N OF OFK WITH LITTLE DROP OFF NOTED BHND PCPN IN CNTRL/WRN NEBR. SO DESPITE DRY LOW LVLS...EVAPORATIVE COOLING NOT ENOUGH TO MAKE PCPN FREEZING OR FROZEN. QUESTION IS WHAT TO DO WITH WINTER WX ADVSRY EXTREME NE. WL HAVE TO DISCOUNT THE ETA WITH PCPN TYPE...ETAS FCST SOUNDINGS TOO COLD AND SFC LOW TRACK TOO FAR S. WL LEAN TWD NGM/AVN COMPROMISE. WL NOT MENTION ANY FREEZING RAIN NOW AND MAIN QUESTION IS HOW MUCH PCPN WL BE LEFT WHEN COLD AIR ARRIVES TWD 18Z AND TURNS ANY PCPN TO SNOW. QG FORCING CONTS IN NERN ZONES UNTIL ARND 18Z BUT IS E OF ALL OF THE FCST AREA BY 00Z. USING AVN 540 DM 1000-500 MB THICKNESS TO TIME CHANGE TO SNOW...PCPN SHOULD CHANGE TO SNOW NERN ZONES THIS MORNING REACHING OMA VCNTY ARND 18Z. WITH WIND TO INCREASE AND PSBLY A FEW INCHES OF SNOW NERN ZONES WL CONT WINTER WX ADVSRY THERE AND PUSH IT INTO EARLY AFTN. WINDS WILL ALSO HAVE TO BE WATCHED AS 850 MB WNDS IN 45 TO 55 KT RANGE FCST TO OVERSPREAD FCST AREA BY 00Z. FALLING TEMPS STILL LOOK GOOD FOR AFTN...BUT WL RAISE HIGHS BFR THEN A LTL. SKIES SHOULD BE CLR OR CLR TNGT WITH STRONG COLD ADVCTN. TEMPS CURRENTLY IN SINGLE DIGITS OVR MUCH OF ND AND THIS AIR WL EASILY MOV INTO NRN NEBR TNGT. PREV FCST LOWS LOOK GOOD ALL AREAS. SFC WINDS SHOULD DROP OFF LATER TNGT OR EARLY THU WITH SOME WK WRM ADVCTN ALREADY BY LATE AFTN WRN ZONES. AGAIN PREV TEMPS LOOK GOOD ATTM WITH NO CHANGES. .OMA...NONE CHERMOK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 255 AM CST WED JAN 19 2000 FORECAST QUANDARIES: POTENTIAL PCPN ASSOCIATED WITH WRAP AROUND MOISTURE NW...TEMPERATURES. CURRENT AWOS/ASOS OBSERVATIONS...REGIONAL SATELLITE IMAGERY...AND SURFACE/LAPS ANALYSIS SHOWING CWA UNDER AN "UMBRELLA" OF LOW LEVEL CLOUDINESS...N SURFACE WINDS...WITH TEMPS/DEWPOINTS 30 TO 35/UPPER 20S TO LOW 30 RANGES. 1023MB SURFACE HIGH POSITIONED IN THE VICINITY OF THE OHIO/MISSISSIPPI RIVER DELTA AREA. UPPER LEVEL CHART ANALYSIS/RUC SHOWING SURFACE PATTERN ASSOCIATED WITH PROGRESSIVE NW FLOW...WITH 300 MB 100+ KT JET SUPPORTING UPPER LEVEL MOISTURE ADVECTION INTO REGION. 00Z WED MODEL RUNS INITALIZATION AND PROGGED EVOLUTION THROUGH 00Z FRIDAY GENERALLY SIMILAR...ESPECIALLY IN THE UPPER LEVEL PATTERN. MODELS SHOWING QUICK MOVING SURFACE FEATURES AS HIGH PRESSURE CENTERED OVER REGION BY 12Z WED MOVES EASTWARD WITH A LOW PRESSURE SYSTEMS DEVELOPING ACROSS THE MISSOURI OZARKS BY 00Z THU. SYSTEM SHOULD MOVE THROUGH ENTIRE CWA AFTER 06Z THU...WITH HIGH PRESSURE BUILDING OUT OF THE CENTRAL U.S....INFLUENCING REGIONAL WEATHER AFTER 12Z THU. NW UPPER LEVEL PATTERN WILL REMAIN THROUGHOUT PERIOD WITH BEST TROUGHING/SHORTWAVE PASSAGE HAPPENING AROUND 06Z THU. LATEST MODEL/PROGNOSTIC DISCUSSIONS POINT TO A LESS AMPLIFIED MODEL SOLUTIONS FOR THE E U.S. WITH BEST LOW PRESSURE SURFACE DEVELOPMENT FURTHER OFF THE CENTRAL ATLANTIC COAST BY 00Z FRI THAN EXPECTED. AVN COMPROMISE SOLUTION IS PREFERRED. ALSO...WITH AN INVERTED SURFACE TROUGH EXPECTED TO DEVELOP NW OF THE LOW AS THE UPPER TROF BECOMES NEGATIVELY TILTED...SURGE OF ARCTIC AIR EXPECTED TO SPILL SW BEHIND SYSTEM INTO THE GULF COAST REGION BY EARLY THU. TODAY...WILL CONTINUE WITH SKY CONDITION WORDING OF MOSTLY CLOUDY SKIES AS SURFACE WINDS TO REMAIN S AND CONTINUE SUPPORTING SHALLOW LOW LEVEL CLOUDINESS LAYER. PCPN COULD POSSIBLE DEVELOP LATE AFTERNOON WEST AND CENTRAL...DEPENDING ON LOW PRESSURE SYSTEM MOVEMENT. WILL MENTION WIDELY SCATTERED POPS LATE AFTERNOON WEST. TONIGHT...MAIN FORECAST QUANDRY CENTERS AROUND PRECIPITATION TYPE NW PLATEAU. WILL LEAN TOWARD LIKELY AVN POPS THROUGH 12Z THU. LOOKING AT MODEL SOUNDING DATA FOR CSV 06Z-12Z...BELIEVE THERE IS A POSSIBILITY FOR SOME FORM OF MIXED PRECIPITATION OVER THIS AREA. THURSDAY...WITH RAPID MOVEMENT OF SYSTEM EAST EXPECTED...PCPN SHOULD END OVER E SECTIONS BY 12Z THU. LOOK FOR DECREASING CLOUDINESS TO BEGIN WITH WESTERN PORTIONS OF CWA EXPERIENCING PARTLY CLOUDY SKIES BY LATE AFTERNOON. TEMPS...LOW LEVEL CLOUD COVER YESTERDAY KEPT TEMPS SEVERAL DEGREES COOLER THAN BOTH AVN FAN/NGM MOS NUMBERS. THOUGH THE AVN SOLUTION IS PREFERED...SEE NO JUSTIFICATION FOR TEMPS IN THE LOWER 50S WITH CURRENT WEATHER SCENARIO AND WILL LEAN TOWARD COOLER NGM MOS NUMBERS. WILL GO SLIGHTLY BELOW BOTH AVN/NGM MOS NUMBERS FOR THURSDAY MORNING LOWS AS COLD AIR ADVECTION EPISODE FROM NW EXPECTED TO INFLUENCE TEMPS BY THEN. WITH NW WINDS DEVELOPING AND APPROACHING BRISK CRITERIA...WILL LEAN TOWARD COOLER AVN MOS HIGHS. THANKS FOR COORDINATION MRX. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... KBNA 045/032/037/025 1610 KCSV 042/028/033/020 0610 .BNA...NONE. $$ 14 JBW tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 240 AM CST WED JAN 19 2000 ...FIRST WIDESPREAD WINTER STORM FOR CWA THE CHALLENGE TODAY... INITIAL GLANCE AT SETUP WOULD SUGGEST FAIRLY EASY PREDICTIONS BUT THERMAL FIELDS OVER SRN/SW THIRD OF STATE THROWING MONKEY WRENCH IN THE WORKS THIS MORNING. INITIAL VORT MAX OVR NW NEB WITH LARGE WWA AREA OF CLOUDS AND SOME RAIN OVER CEN/ERN NEB. THIS MOVING EAST AND WILL SERVE TO MOISTEN COLUMN. NO PRECIP AT 830Z YET IN WRN IA. REGIONAL RADAR LIKELY SHOWING SOME BRIGHT BANDING VNTY KOLU IN NEB. SFC LO WEST OF KVTN WITH ONE WARM FRONT THRU SE SD INTO MN...AND 2ND THRU ERN NEB TO ERN KS. NRN STREAM VORT MAX NOW WELL INTO MONTANA WITH SFC REFLECTION AND PRES RISE IN CEN MONT AS WELL. ALL MODELS POINTING TO A SNOW EVENT OVER NRN HALF CWA...MOST IN NORTH WITH PERHAPS A LITTLE MIX OR FZRA EVENT IN SRN CWA THIS MORNING. THEN BY MID AFTERNOON...WINDS SWING FROM SE TO NW AND PICK UP DRAMATICALLY. DARKENING NOTED ON H20 VAPOR OVER NRN ROCKIES STATES AND MODEL POT VORT PROGS WILL CERTAINLY SUPPORT 30-40 MPH OVER WRN CWA...5 MPH LESS IN EAST...IF I BREAK IT UP THAT WAY. IN THE DETAILS...00Z NGM AND 06Z RUC HANDLING SFC FEATURES BEST OVER PLAINS AT 08Z. PLENTY OF WARM AIR SURGING INTO ERN NEB AND EVEN SW IA. THUS WILL START OUT DAY IN POSITIVE C NUMBERS IN SRN CWA. THICKNESSES ALSO POINT TO A BRIEF TIME THIS MORNING OF MIX/SLEET/OR FZRA DOWN THERE BEFORE CHANGING EVAP COOLING AND THEN STRONG CAA CHANGES PRECIP TO SNOW. AMOUNTS PROGGED TO BE LIGHT ENUF THERE TO GO NO HEADLINES THERE. OVER NRN CWA...DENDRITIC ZONE...GARCIA... 15:1 LIQUID SNOW RATIO ALL POINT TO 4 TO 6 OR 4 TO 7 INCHES. BEST LIFT AROUND 18Z UP THERE THO BEST LIFT IN MN. NICE STORM FOR THEM. IN BETWEEN WINTER WX ADVISORY FOR INITIAL MIX/SLEET/FZRA THIS MORNING THEN 2 TO 4 INCHES LATER. NOT OVERLY CONCERNED ABOUT AMOUNTS IN CENTRAL...WEST TO EAST STRIPE...BUT WINDS FROM 21Z ON WILL REALLY JUMP UP THERE. 30-40 MPH ANYWAY WITH GREAT SINKING AND POT VORT REACHING TOWARD SFC. THEN WITH CLEARING TONIGHT...COLD TEMPS SET IN NEXT COUPLE OF DAYS AT LEAST. CURRENT ZFP HANDLES THIS. CERTAINLY WON'T GO ABOVE THEM. THX FOR COORD WITH ARX/OAX/MPX/FSD. .DSM...WINTER STORM WARNING THROUGH THIS EVENING FOR IAZ004>007-015>017-023>026 SNOW AND BLOWING SNOW ADVISORY THROUGH THIS EVENING FOR IAZ027-028-033>039-047>050 WINTER WEATHER ADVISORY THROUGH THIS EVENING FOR IAZ044>046-057>062-072>075 SEARCY ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 1033 AM CST TUE JAN 18 2000 SURFACE LOW ANALYZED BETWEEN NORFOLK AND LINCOLN NEBRASKA AROUND 15Z. ISALLOBARIC TRENDS SHOW THE GREATEST 3-HR. PRESSURE FALLS ACROSS THE ST. JOE AND KC AREAS. IN LIGHT OF THIS...WOULD EXPECT THE LOW TO TRACK SOUTHEAST ACROSS EXTREME NORTHEAST KANSAS AND INTO NORTHWEST MISSOURI. THIS IS SUPPORTED BY INFO GLEANED FROM THE RUC2. CLEARING LINE BEHIND THE FRONT IMPINGING ON NORTH-CENTRAL KANSAS. WILL UPDATE THE ZONES AND REMOVE BECOMING IN THE FIRST PERIOD OVER THIS AREA. WILL ALSO FRESHEN THE WORDING JUST A TOUCH...AND TAKE A PEEK AT TEMPERATURES. SURFACE WINDS SHOULD BECOME WESTERLY OVER THE CWA SOMEWHERE AROUND LUNCHTIME...THEN BECOME NORTHWESTERLY BY LATE AFTERNOON. PROFILER DATA FROM MCCOOK NEBRASKA SHOWS SPEEDS APPROACHING 50 KTS AT 850 MB. BELIEVE THAT THE RUC2 HAS A GOOD HANDLE ON THE WINDS...WITH 850 MB WINDS PROGGED TO BE AROUND 50 KTS OVER MOST OF THE CWA DURING THE LATE AFTERNOON. CURRENT THINKING IS TO HOLD OFF ON A WIND ADVISORY...AND MAYBE HOIST THE ADVISORY WITH THE AFTERNOON PACKAGE. THANKS ICT/HSI FOR COORDINATION. 65/63 .TOP...NONE. ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND KS 904 AM MST WED JAN 19 2000 UPDATED MORNING PACKAGE TO INCREASE WINDS. KGLD ALREADY GUSTING TO 35 MPH. LATEST RUC/RUCII/6Z ETA INDICATING BOUNDARY/850 WIND SPEEDS TO INCREASE UNDER GOOD SUBSIDENCE BEHIND APPROACHING COLD FRONT. RED WILLOW PROFILER INDICATING 40 KTS AT 850MB. STRONG 3 HOUR PRESSURE RISES CURRENTLY OVER SOUTH DAKOTA WILL MOVE TOWARD THE CENTRAL AND EASTERN CWA WHERE WINDS ARE EXPECTED TO INCREASE TO 30 TO 40 MPH WITH GUSTS TO 50 MPH. FURTHER WEST...RUCII INDICATING THE SAME THING AS FAR AS WINDS WITH OTHER MODELS SHOWING A LITTLE LESS. NEEDLESS TO SAY...A WIND ADVISORY HAS BEEN ISSUED FOR THE ENTIRE CWA. TEMPS SEEMED TO HAVE PEAKED OR ARE VERY CLOSE SO I WONT CHANGE THEM. REMAINDER OF FORECAST UNCHANGED. .GLD...WIND ADVISORY IN EFFECT UNTIL 5 PM MST (6 PM CST) FOR THE ENTIRE FORECAST AREA. THEDE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1110 AM EST WED JAN 19 2000 ORGANIZED LAKE EFFECT BANDING HAS ALL BY DISSIPATED ACROSS NRN LOWER MI...WITH SOME MINOR BANDING PERSISTING ACROSS ERN UPR MI ATTM. LOWERING INVERSION HEIGHTS TO AROUND 3 KFT...DRYING AT MID LEVELS AND INCREASING LOW LEVEL DIRECTIONAL SHEAR IS RESPONSIBLE FOR THIS DISSORGANIZATION ACROSS NRN LOWER MI. ATTENTION TURNS TO SYNOPTIC SNOWS MOVING OUT OF MN INTO WI LATE THIS MORNING ASSOCIATED WITH ISENTROPIC ASCENT (I280) AHEAD OF AN ARCTIC BOUNDARY. LATEST RUC AND FIRST LOOK AT THE NEW ETA RUN SHOWS MAJORITY OF ISENTROPIC ASCENT AND 850-700 MB Q-VECTOR CONVERGENCE SLIDING S OF THE CWA OVER SRN WI AND SRN LOWER MI THIS AFTERNOON AND EVENING. AREA OF SN OVER MN ATTM IS JUST A BIT FARTHER N THAN ANTICIPATED BY THE MODELS. WILL MAINTAIN LIKELY POPS FOR THIS AFTERNOON ACROSS AREAS S OF A LINE FROM TVC TO HARRISVILLE. WILL KEEP SCT SHSN FOR FAR NRN LOWER MI ZONES AS SOME WEAK LAKE EFFECT SNOW PERSISTS WITH SHALLOW COLD AIR STILL IN PLACE. WILL KEEP CATEGORICAL POPS FOR CHIPPEWA COUNTY WHERE INVERSION HEIGHTS WILL STAY AROUND 4 KFT AND IN PROXIMITY TO DEEPER...COLDER AIR... BETTER LOW LEVEL MOISTURE AND LESS LOW LEVEL SHEAR TO DISRUPT LAKE BAND ORGANIZATION. .APX...NONE. EME mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 940 AM EST WED JAN 19 2000 SATELLITE AND SURFACE OBS INDICATE WIDESPREAD LOW CLOUDS ACROSS STATE...WITH AREAS OF FOG. ALSO...MID TO UPPER LEVEL CLOUDS SPREADING INTO AREA. LIGHT PRECIP MOVING INTO WEST GA...ASSOCIATED WITH ISENTROPIC LIFT. SHOULD HOLD OFF IN CSRA UNTIL THIS EVENING. WEAK 850MB CAA THIS AFTERNOON INDICATED BY RUCII. WINDS IN THE BOUNDARY LAYER LIGHT SO LITTLE MIXING EXPECTED. SO...WILL CUT TEMPS AND GO MID 40S NE OF CAE TO UPPER 40S SOUTH MIDLANDS FOR HIGHS...AND GO MOSTLY CLOUDY. .CAE...NONE. AWP sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 822 PM EST TUE JAN 18 2000 HI PRESS RIDGE TO REMAIN ACRS THE FA THRU 00Z THU. WK STORM SYS TO MOVE SE ACRS THE GREAT LKS REGION OVRNITE TONITE...AND THEN ACRS THE MID-ATLANTIC REGION ON WED. 12Z ETA/AVN A LIL TOO WK WITH THIS SFC LOW/S CENTRAL PRESS AT 00Z...21Z RUC DOING A BETTER JOB. 21Z RUC SHOWS LT WINDS OVRNITE WITH TEMPS GETTING DOWN INTO THE NEGATIVE SINGLE NUMBERS AND TEENS BY 09Z. ALSO SHOWS SOME MID/HI CLDS TO MOVE INTO NORTHERN NY AFTER 06Z...AND THIS SUPPORTED BY 12Z ETA/AVN MOISTURE FIELDS AS WELL. IR SAT PIX SHOW JUST SOME HI CLDS ACRS THE FA ATTM. THICKER CLDS ASSOCIATED WITH GREAT LKS SYS TO MOVE THROUGH ALL OF LK ONT BY AFTER 04Z. FA TO BE UNDER WK H85 CAA THRU 18Z WED...WITH SOME WK WAA TAKING PLACE AFTER THAT IN NORTHERN NY. LOOKS TO ME LIKE JUST NORTHERN NY WILL SEE ANY SIGNIFICANT CLOUDINESS ON WED...ESPECIALLY IN THE AFTERNOON HOURS. 12Z ETA-WX CLD PRODUCT SUPPORTS THIS THINKING. HAVE WIDENED LOW TEMP RANGES FOR TONITE IN THE CHAMP/ST LAW VLYS BASED ON CURRENT TRENDS. HAVE GONE A LIL MORE OPTIMISTIC FOR CLD COVER TOMORROW...ESPECIALLY IN VT. ALL OTHER CHANGES TO ZONES PURELY COSMETIC. WORK ZONES AWAY. FINAL ZFP TO FOLLOW AFTER QUICK LOOK AT LATEST LAMP DATA. .BTV...NONE. MURRAY vt