INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HANFORD CA 1000 AM PST TUE DEC 17 2002 UPDATED TO EXTEND SNOW ADVISORY INTO EVENING FOR SOUTHERN SIERRA MOUNTAINS AND TO ISSUE SNOW ADVISORY FOR KERN MOUNTAINS WV IMAGERY AND ETA/GFS ANALYSIS DEPICT NOSE OF STRONG 140 KT H25 JET STREAK JUST OFFSHORE. LFQ OF JET SHOULD PASS OVER THE SOUTHERN CWFA TODAY...ENHANCING LIFT ACROSS THE SOUTHERN SIERRA AND ADDING TO THE SNOWS FROM YESTERDAY. IN FACT...TUOLUMNE MEADOWS AT 9200 FEET REPORTED 29 INCHES OF SNOW IN THE PAST 24 HOURS. OTHERWISE...COLD AIR ALOFT WILL CONTINUE TO BE ADVECTED INTO THE AREA DURING THE DAY. WITH SEVERAL VORT LOBES RIDING THE FLOW...SCATTERED SHOWERS SEEM LIKE A GOOD BET WITH LINGERING MOISTURE AND SOME LOW LEVEL DIURNAL HEATING. RUC/MESOETA FORECAST MODEL SOUNDINGS SHOW NEGATIVE LIFTED INDICES DURING THE DAY...BUT WITH WEAK DIRECTIONAL/SPEED SHEAR AND LOW WET BULB ZERO HEIGHTS...MAIN THREAT WILL BE FROM HAIL. UNFORTUNATELY...BELIEVE THAT THESE LIFTED INDICES MAY BE TOO CONSERVATIVE...SINCE MODELS SEEM TO SUGGEST MORE CLOUDINESS PERSISTING THAN WHAT CURRENT SATPIX DOES...AND ANY ADDED SUNSHINE WILL ACT TO FURTHER DESTABILIZE THE LOWER ATMOSPHERE. THUS...CURRENT WORDING OF THUNDER IN ZONES LOOKS RIGHT ON. THIS ACTIVITY SHOULD RAPIDLY SUBSIDE AFTER SUNSET. MODEL SUITES SUGGEST LINGERING MOISTURE/OMEGA OVERNIGHT SO THINK VALLEY FOG THREAT WILL REMAIN PATCHY OR LESS. WEDNESDAY SHOULD BRING MUCH MORE TRANQUIL WEATHER...AS SUBSIDENCE ALOFT TAKES HOLD. MAY SEE MORE WIDESPREAD FOG WEDNESDAY NIGHT/THURSDAY WITH WEAKER WINDS ALOFT. THIS RESPITE FROM THE ACTIVE WEATHER IS SHORT LIVED AS THE NEXT WAVE REACHES OUR VICINITY BY THURSDAY AFTERNOON. BURGER .HNX...SNOW ADVISORY FOR THE SOUTHERN SIERRA NEVADA TODAY THROUGH THIS EVENING. ...SNOW ADVISORY FOR THE KERN COUNTY MOUNTAINS TODAY THROUGH THIS EVENING. ca INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HANFORD CA 900 AM PST TUE DEC 17 2002 WV IMAGERY AND ETA/GFS ANALYSIS DEPICT NOSE OF STRONG 140 KT H25 JET STREAK JUST OFFSHORE. LFQ OF JET SHOULD PASS OVER THE SOUTHERN CWFA TODAY...ENHANCING LIFT ACROSS THE SOUTHERN SIERRA AND ADDING TO THE SNOWS FROM YESTERDAY. IN FACT...TUOLUMNE MEADOWS AT 9200 FEET REPORTED 29 INCHES OF SNOW IN THE PAST 24 HOURS. OTHERWISE...COLD AIR ALOFT WILL CONTINUE TO BE ADVECTED INTO THE AREA DURING THE DAY. WITH SEVERAL VORT LOBES RIDING THE FLOW...SCATTERED SHOWERS SEEM LIKE A GOOD BET WITH LINGERING MOISTURE AND SOME LOW LEVEL DIURNAL HEATING. RUC/MESOETA FORECAST MODEL SOUNDINGS SHOW NEGATIVE LIFTED INDICES DURING THE DAY...BUT WITH WEAK DIRECTIONAL/SPEED SHEAR AND LOW WET BULB ZERO HEIGHTS...MAIN THREAT WILL BE FROM HAIL. UNFORTUNATELY...BELIEVE THAT THESE LIFTED INDICES MAY BE TOO CONSERVATIVE...SINCE MODELS SEEM TO SUGGEST MORE CLOUDINESS PERSISTING THAN WHAT CURRENT SATPIX DOES...AND ANY ADDED SUNSHINE WILL ACT TO FURTHER DESTABILIZE THE LOWER ATMOSPHERE. THUS...CURRENT WORDING OF THUNDER IN ZONES LOOKS RIGHT ON. THIS ACTIVITY SHOULD RAPIDLY SUBSIDE AFTER SUNSET. MODEL SUITES SUGGEST LINGERING MOISTURE/OMEGA OVERNIGHT SO THINK VALLEY FOG THREAT WILL REMAIN PATCHY OR LESS. WEDNESDAY SHOULD BRING MUCH MORE TRANQUIL WEATHER...AS SUBSIDENCE ALOFT TAKES HOLD. MAY SEE MORE WIDESPREAD FOG WEDNESDAY NIGHT/THURSDAY WITH WEAKER WINDS ALOFT. THIS RESPITE FROM THE ACTIVE WEATHER IS SHORT LIVED AS THE NEXT WAVE REACHES OUR VICINITY BY THURSDAY AFTERNOON. BURGER .HNX...SNOW ADVISORY FOR THE SOUTHERN SIERRA NEVADA NORTH OF KERN COUNTY TODAY. ca AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND KS 845 PM MST TUE DEC 17 2002 STRONG POCKET OF 700-500 OMEGA SLIDING SOUTH/SOUTHEAST ALONG THE COLORADO FRONT RANGE FORECAST BY THE RUC TO MOVE INTO THE WESTERN CWA. KLIC REPORTED A BRIEF INCREASE IN WINDS WITH SNOW FALLING. ALTHOUGH BRUNT OF ENERGY STAYS TO OUR WEST FEEL SOME PRECIP WILL FALL OVER THAT PART OF THE AREA SO ADDED ISOLATED SNOW SHOWERS. OVER THE CENTRAL AND EASTERN CWA PRECIP FALLING ON PERIMETER OF DEVELOPING SURFACE LOW. PRECIP LOOKS LIKE ITS REACHING THE GROUND OVER THE EASTERN CWA BUT CANT VERIFY TIL IT RUNS OVER KHLC SHORTLY. ALTHOUGH THE CENTRAL CWA IN BETWEEN THE TWO FEEL THAT A FEW POCKETS OF PRECIP ARE POSSIBLE AS COLORADO DISTURBANCE SLIDES IN THIS GENERAL DIRECTION. IN SUMMARY ADDED 20 POPS TO THE ENTIRE CWA AND TWEAKED WINDS A BIT. .GLD...NONE. DDT ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND KS 630 PM MST TUE DEC 17 2002 AT 01Z TEMPS RANGED FROM 30 DEGREES AT KHLC TO 45 IN TRIBUNE. FORECAST MINS ALREADY REACHED OVER THE EASTERN CWA WHERE LIGHT WINDS AND LITTLE CLOUD COVER ALLOWING FOR GOOD RADITIONAL COOLING. TO OUR SOUTHWEST AND WEST RUC 700-500 OMEGA PEGGING THE AREA OF STRUGGLING SHOWER ACTIVITY. THIS WILL SLOWLY DISSIPATE OVER THE NEXT FEW HOURS AS SURFACE FRONT MOVES THROUGH. FOR THE UPDATE I TWEAKED MINS DOWN A FEW DEGREES TO ACCOUNT FOR THE HILL CITY CURRENT OBSERVATION AT THE MAV GUIDANCE LOW OF 18 AT LIMON. WITH THE MAV DOMINANCE WITH LOW TEMPS FEEL FORECAST LOWS IN GOOD SHAPE...JUST TWEAKED A BIT. OTHERWISE...ONCE THE LOW BEGINS DEPARTING THE AREA WINDS WILL INCREASE A BIT AND KHLC TEMPS WILL PROBABLY STABILIZE OR RISE JUST A BIT. THAT AREA WILL ALSO SEE AN INCREASE IN CLOUD COVER. OTHER THAN A TWEAK TO MIN AND HOURLY GRID TEMPS NO OTHER CHANGES MADE. .GLD...NONE. DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 210 PM MST TUE DEC 17 2002 FORECAST CHALLENGES ARE PRECIPITATION CHANCES TONIGHT...WINDS TOMORROW AND THURSDAY...AND TEMPERATURE TRENDS THROUGHOUT. 12Z UPPER AIR ANALYSIS SHOWED 150 KT JET AXIS MAKING ITS WAY INLAND ACROSS THE DESERT SOUTHWEST. SEVERAL IMPULSES WERE SPINNING UP ALONG THE CYCLONIC SHEAR SIDE OF THE JET AXIS...NEAR AND JUST DOWNSTREAM OF THE FOUR CORNERS. THIS JET WAS CARVING OUT A BROAD TROUGH OVER THE WESTERN US...WITH ASSOCIATED COLD POOL AND MOISTURE EVIDENT ON WATER VAPOR IMAGERY. MODEL INITIALIZATION QUITE SIMILAR. IN THE LOWER LEVELS...LOW CLOUDS AND FOG NEAR QUASI STATIONARY FRONTAL BOUNDARY ADVANCED JUST EAST OF THE FORECAST AREA BUT NO FURTHER. SURFACE PRESSURES WERE FALLING AS LOW WAS SPINNING UP OVER SOUTH CENTRAL FORECAST AREA. AVN INITIALIZED BEST WITH SURFACE PRESSURE AND WIND FIELDS. 18Z QPF VERIFICATION FAVORS THE AVN IN THE DRIZZLY/LIGHT PRECIPITATION TO THE EAST...BUT THE ETA WITH ISOLATED SNOW SHOWERS NEAR RAPID CITY. TONIGHT...UPPER LOW BEGINS TO DEEPEN OVER WESTERN SOUTH DAKOTA IN THE TROUGH AXIS. BROAD SURFACE LOW PRESSURE WILL THUS TEND TO REDEVELOP WELL NORTHEAST OF OUR FORECAST AREA...REINFORCING THE WEST TO NORTHWEST SURFACE FLOW. JET AXIS REMAINS SOUTH AS IT CYCLONIC CURVES ACROSS THE RED RIVER VALLEY. ONLY LIFT IS IN THE 0Z TO 6Z TIMEFRAME...WITH LIMITED MID LEVEL MOISTURE AVAILABLE. LOW LEVELS ARE QUITE DRY AT THIS TIME...SO ANY PRECIPITATION THAT DEVELOPS WILL NOT LIKELY REACH THE GROUND. DOWNSLOPING SURFACE WINDS ARE ALSO A LIMITING FACTOR. LATEST 20 KM RUC...21Z...CONTINUES TO BE DRY TONIGHT. AFTER 6Z...SUBSIDENCE ERODES THE LAST VESTIGES OF MID LEVEL MOISTURE. WEDNESDAY...UPPER LOW IS OVER THE DAKOTAS WITH NORTHWEST FLOW OVER THE HIGH PLAINS. CROSS SECTIONS SHOW SCATTERED MID AND HIGH CLOUDS DURING THE AFTERNOON ASSOCIATED WITH WRAP AROUND. DOWNWARD OMEGA IS WEAK AT BEST (3 MICROBARS/SEC) AND BRIEF...AROUND 18Z. 20 KM RUC SHOWS 2-3 MB 3 HOUR PRESSURE RISES REMAINING SOUTH AND EAST OF THE AREA THROUGHOUT THE DAY. MOS GUIDANCE IS ALL BELOW THE BREEZY CATEGORY. WILL GO WITH 10 TO 20 MPH AND THAT WILL MOSTLY BE EARLY AS PRESSURE GRADIENTS RELAX IN THE AFTERNOON. THURSDAY...BOTH GFS AND ETA 850-700 MB THICKNESSES ARE A LITTLE LOWER AS COMPARED TO THURSDAY. THIS MAKES SENSE GIVEN THE PROLONGED COLD ADVECTION PATTERN AS THE FORECAST AREA IS IN THE DEEP NORTHWEST FLOW BETWEEN THE LOW TO THE NORTHEAST AND RIDGING OVER THE DESERT SOUTHWEST. MOS GUIDANCE IS IN THE WINDY CATEGORY DURING THE AFTERNOON...ESPECIALLY IN THE WEST. UPPER 30S TO LOWER 40S CONTINUES TO LOOK GOOD. FRIDAY...GFS AND EXTENDED ETA ARE ON THE SAME PAGE WITH SHORTWAVE RIDGING OVER THE FORECAST AREA. WITH MORE OF A WESTERLY FLOW ALOFT LEE TROUGH WILL DEVELOP WITH DOWNSLOPING. THICKNESSES BEGIN TO RISE WITH TEMPS IN THE 40S. EXTENDED...GFS SWEEPS A NORTHERN STREAM SHORTWAVE ACROSS THE FORECAST AREA ON SATURDAY AS GREAT LAKES CUT OFF BEGINS TO OPEN UP. THIS IS IN REASONABLE AGREEMENT WITH OTHER ENSEMBLE MEMBERS. MOISTURE RETURN IS LIMITED. THE LATTER HALF OF THE EXTENDED THE ENSEMBLES SHOW SHORTWAVE ENERGY CASCADING DOWN THE NORTHERN STREAM FROM A PACIFIC NORTHWEST RIDGE...MOST LIKELY TRACKING THROUGH THE NORTHERN PLAINS. SOUTHERN STREAM IS RELATIVELY QUIESCENT WITH LOW AMPLITUDE TROUGHING SOUTH OF CALIFORNIA. THIS IS ESSENTIALLY A CONTINUATION OF THE BLOCKY PATTERN THAT HAS DOMINATED SINCE NOVEMBER. PERSISTENCE SEEMS TO BE THE BEST COURSE...DRY WITH SEASONAL TEMPERATURES. .GLD...NONE. JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1045 PM EST TUE DEC 17 2002 MAIN FCST CONCERNS OVERNIGHT ARE PCPN TIMING/COVERAGE/TYPE. WV IMAGERY INDICATED STRONG LEAD SHRTWV LIFTING N FROM WRN IA WHILE UPSTREAM STRONG 120 KT H3 JET EXTENDED FROM THE SW INTO THE SRN PLAINS. AT THE SFC...A WARM FRONT EXTENDED THROUGH NRN MO INTO SRN IL FROM LO PRES OVER WRN KS. ARCTIC HI PRES WAS LOCATED OVER NRN QUEBEC KEEPING COLD DRY LOW LVL ESE FLOW TOWARD UPR MI. TEMPS OVER UPR MI REMAINED IN THE UPPER 20S F TO AROUND 30...EXCEPT ALONG LK MI WHERE TEMPS REMAINED AROUND 34. DEWPOINTS OVER UPR MI AND UPSTREAM WERE GENERALLY IN THE LOWER 20S. RADARS AND SFC OBS INDICATED EXPANDING AREA OF RA/TSRA OVER SRN MN AND INTO SW WI...FUELED BY STRONG ISENTROPIC LIFT AND THETA-E ADVECTION WITH 50 KT H8 JET...PER PROFILERS. 00Z ETA SUGGESTS PCPN WILL CONTINUE TO EXPAND AND MOVE INTO MOST OF UPR MI BY 12Z WHILE 00Z RUC IS SLOWER...BRINGING PCPN TO WI BORDER BY 12Z. ALTHOUGH THE ETA IS LIKELY A BIT QUICK WITH QPF INTO THE AREA GIVEN VERY DRY LOW LEVELS...PER 00Z KAPX SNDG...STRENGTH OF MOISTURE ADVECTION AND 290K-295K ISENTROPIC AFT 12Z WILL ALLOW PCPN TO DEVELOP QUICKLY. ETA FCST SNDGS FROM 09Z-12Z WITH 900-750 MB LYR ABV FREEZING...PEAKING AT 4C-5C SHOULD BE ENOUGH TO MELT PCPN FOR MAINLY -FZRA. SO...HAVE MENTIONED FZRA FOR MAINLY THE SOUTH WITH LESS COVERAGE FARTHER NORTH. MARINE LYR WARMING...SHOULD KEEP PCPN AS MAINLY RAIN ALONG LK MI FROM MNM TO ESC. .MQT...FREEZING RAIN ADVISORY LATE TONIGHT INTO WED MIZ002-009>012-084. FREEZING RAIN ADVISORY WED MIZ001-003>007-013-014-085. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 927 PM EST TUE DEC 17 2002 REGIONAL RADAR DATA SHOWS AN AREA OF RETURNS ALREADY MOVING OVER SOUTHWEST LOWER MICHIGAN...WITH SCATTERED RETURNS DEVELOPING OVER SOUTHEAST LOWER MICHIGAN. HOWEVER THE APX 88D SHOWS DRY CONDITIONS OVER NORTHERN LOWER MICHIGAN AND EAST UPPER. THE PRECIPITATION MOVING OVER SOUTHERN LOWER MICHIGAN...HAS FORMED IN ADVANCE OF A WARM FRONT LOCATED OVER THE OHIO VALLEY. THE LEADING EDGE OF THIS PRECIPITATION CORRELATES WITH 850MB DEW POINTS INCREASING FROM NEG NUMBERS TO AROUND +2C. ALSO...THE I295 SURFACE SHOWS ISENTROPIC LIFT ALREADY AFFECTING MUCH OF SOUTHERN LOWER MICHIGAN. THE LATEST RUC SHOWS THIS AREA OF LIFT TO MOVE NORTH THIS EVENING/OVERNIGHT AND BEGIN AFFECTING THE SOUTHWEST PORTIONS OF THE FORECAST AREA AROUND MIDNIGHT...ADVANCING TO LOCATIONS AS FAR NORTH AS GRAND TRAVERSE BAY OVERNIGHT. MODEL SOUNDINGS SHOW STRONG WAA IN MID LEVELS...GENERATING AN ELEVATED WARM LAYER WITH A DEPTH OF 4500 FEET AND A MAX TEMPERATURE AROUND 5C...DEVELOPING OVER MANISTEE AROUND MIDNIGHT AND THEN OVER GRAND TRAVERSE BAY AREAS AROUND 12Z WED. THEREFORE DUE TO THE LATEST MODEL DATA...AND SATELLITE AND RADAR DATA...WILL MENTION FREEZING RAIN DEVELOPING TONIGHT OVER THE SOUTHERN PORTIONS OF THE FORECAST AREA. WILL MENTION MOSTLY CLOUDY SKIES MOST OTHER ZONES TONIGHT. .APX...WINTER WEATHER ADVISORY...TONIGHT...MIZ020-025-026-031>033 SWR mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1222 PM EST TUE DEC 17 2002 ...MAIN CONCERN FOR UPDATE TODAY IS CLOUDS/TEMPS...THEN CONCERN SHIFTS TO POTENTIAL FZRA ACCUMULATION LATE TONIGHT INTO WEDNESDAY. WV LOOP AND RUC ANALYSIS SHOW AMPLIFIED UPR RDG AXIS HAS MOVED EAST AS SHEARED OUT SHRTWV LIFTS THRU UPR MI AND THE WRN GRT LAKES ATTM. THIS SHRTWV HHWVR HAS BROUGHT LTL IN WAY OF MID-HIGH CLDS TO U.P AS 12Z SNDGS...ESPECIALLY UPSTREAM SNDG AT KAPX...SHOW INFLUENCE OF HIGH PRES RDG AND VERY DRY AMS DOMINATING. VERY SHALLOW MSTR LYR (1-1.5 KFT) TRAPPED UNDER MASSIVE SUBSIDENCE WHICH WAS RESPONSIBLE FOR WIDESPREAD LOW CLD DECK ACROSS CWA THIS MORNING IS NOW SHOWING SIGNS OF DISSIPATING WITH MIXING FM DIURNAL HEATING. OTHER MAIN FEATURE WHICH WL IMPACT OUR WX LATE TONIGHT INTO WED IS STG 120+ KT 3H JET FEEDING INTO SRN CA EJECTING SHRTWV/SPEED MAX INTO FOUR CORNERS REGION. THIS SRN STREAM ENERGY WILL IN TURN TAKE SFC LOW OVR LEE OF ROCKIES AND DRIVE IT INTO NE/KS AND THEN NWD THRU MN WED AFT AND WED NIGHT. THIS SYSTEM WILL BRING THE THREAT OF FREEZING RAIN AND ICE ACCUMULATION TO U.P. LATE TONIGHT AND WEDNESDAY. FOR UPDATE TODAY...GIVEN RECENT VIS SATL TRENDS INDICATING LOW CLDS DISSIPATING IN MOST AREAS WENT WITH MORE OPTIMISTIC PARTLY SUNNY WORDING AND BUMPED TEMPS UP FM UPPER 20S TO LOW TO MID 30S...ESPECIALLY FOR DWNSLPG AREAS ALG LAKE SUPERIOR IN SE FLOW. .MQT...WINTER STORM WATCH LATE TONIGHT INTO WEDNESDAY ALL CWA. VOSS REST OF AFD FM MID SHIFT: TONIGHT THRU WED NIGHT...THE TWO SHORTWAVES OVR WRN 1/3 OF CONUS ARE EXPECTED TO PHASE SOMEWHAT TODAY...WITH SIG SFC LOW DEVELOPING OVR CNTRL PLAINS BY THIS EVENING. 00Z GUIDANCE SEEMS TO BE SETTLING ON SFC LOW TRACKING FM ERN NEB BY TUE EVENING TO W CNTRL MN BY WED EVENING...AND NEAR MN/ONT BORDER BY 12Z THU. ETA/GFS/NGM/CANADIAN ALL INDICATE BULK OF PCPN WILL FALL BTWN 12Z-18Z WED DUE TO LEADING WARM AIR ADVECTION/ISENTROPIC ASCENT...H85-H3 DPVA...AND UPR DIFFLUENCE. ALTHOUGH ETA/GFS SHOW BLYR TEMPS RISING ABOVE 32F BY 12Z WED...THINK PERSISTANT SE FLOW ORIGINATING FM HIGH PARKED OVER JAMES BAY WILL DETER WARMING AT SFC INITIALLY (EXCEPT ALONG IMMEDIATE LAKE MI SHORELINE). AS SFC LOW PARALLELS UPR MI TO WEST SHOULD SEE PASSAGE OF WARM FRONT...ALLOWING EVEN SFC TO WARM CONSIDERABLY. HOWEVER...WITH MOST INTENSE PCPN PROJECTED TO OCCUR OVER A SUB FREEZING SFC LAYER...BELIEVE A POSSIBLY SIGNIFICANT ICE ACCUMULATION (AROUND A QUARTER INCH)...ESPECIALLY WED AM...IS LIKELY. HAVE DECIDED TO HOIST A WINTER STORM WATCH FOR ALL CWA FOR THIS POSSIBILITY. ANOTHER SURGE OF DEEP MOISTURE ROTATES TOWARD UPR MI LATE WED INTO WED NIGHT. ETA/GFS DIFFER WITH W EXTENT OF MOISTURE WITH GFS AFFECTING ALL CWA...AND ETA ONLY ERN HALF OF CWA. THINK ETA IDEA IS SLIGHTLY BETTER AS PRIMARY H3 JET WILL PASS INTO LWR MI AND WOULD EXPECT THIS SECONDARY BAND OF PCPN TO BE TIED CLOSER TO BETTER JET DYNAMICS. BTWN 00Z-06Z H85 WINDS VEER TO SW...AND SFC WINDS SLOWLY RESPOND TO MORE S DIR OVERNIGHT. THINK THAT ALTHOUGH SOME FZG PCPN IS POSSIBLE INITIALLY WITH SECOND SURGE LATE WED AFTN...A GENERAL TRANSITION TO LIQUID PCP WILL OCCUR AS SFC LOW PASSES INTO NRN MN PLACING CWA INTO WARM SECTOR. OTHERWISE...DRIZZLE SEEMS LIKE GOOD POSSIBILITY WITH SUB H85 MOIST LAYER AND INCREASING DRYING ALOFT...ALONG WITH SIG DIRECTIONAL SHEAR. EXPECT STEADY/RISING TEMPERATURES WELL INTO THE 30S AND POSSIBLY INTO THE 40S WITHIN LOW LEVEL WARM ADVECTION REGIME. THU...COULD BE QUITE MILD AS TEMPS TO OPEN THE MORNING WILL BE IN UPR 30S/AROUND 40. SRLY WIND AND MIXING TO H9 WOULD YIELD HIGHS INTO THE MIDDLE 40S (AT LEAST). DEFINITELY POSSIBLE THAT ABUNDANT LOW CLOUDS AND ANY ONGOING DRIZZLE WOULD PUT BREAKS ON ANY TEMP RISE. FOR NOW RAISED TEMPS A LITTLE FM CURRENT UPR 30S...FAVORING THE WARMER AVN MOS. ONLY BROUGHT SNOW INTO FAR WRN ZONES AFT 18Z AS ETA/CANADIAN SHOW 1000-850MB THICKNESS FALLING BLO CRITICAL 1305M LINE OVR WRN CWA BY 00Z FRI. GFS IS SLOWER WITH COLD AIR ADVECTION. KEPT CHANCE OF SNOW FOR THU NIGHT AS SHORTWAVE/DEEPER MOISTURE ROTATES ACROSS UPR LAKES. TRANSITION TO SYNOPTIC THEN LAKE EFFECT SNOW SHOWERS LOOKS GOOD FRI-SAT AS COLDER AIR SPILLS INTO WRN GREAT LAKES. COORD WITH APX/GRB/DLH...THANKS. JLA mi WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION NATIONAL WEATHER SERVICE MISSOULA MT 910 AM MST TUE DEC 17 2002 .SHORT TERM...MINOR ZONE UPDATES BUT STATE IN GOOD SHAPE. VERY LITTLE ACTIVITY IN THE CWA THIS MORNING AS REGION UNDER NVA BETWEEN EXITING SYSTEM AND ANOTHER ALONG THE COAST. SOUTHWEST FLOW AND COLD AIR ALOFT ENOUGH TO JUSTIFIED ISOLATED SHOWERS THIS AFTERNOON. MORNING LAPSE RATES OF 6 DEGREES C/KM AND -30 C ALOFT ACROSS MT SUPPORT MODERATE INSTABILITY. SHORTWAVE ACROSS WEST CENTRAL OR NOT HANDLED TOO WELL BY ANY MODEL EXCEPT THE RUC. HOWEVER...NO PRECIPITATION MAKES IT EAST OF THE CASCADES TODAY ACCORDING TO LATEST MODEL GUIDANCE. MAIN WEATHER IMPACTS IN SHORT TERM WILL BE FELT WHEN THE CORE OF THE COLD AIR/SHORTWAVE...CURRENTLY NEARING 135W...MOVES INLAND LATE TONIGHT AND WEDNESDAY. MOST SHOWER THREAT WILL BE ACROSS THE ID AND NORTHWEST MT MOUNTAINS THOUGH. WILL ADJUST A FEW TEMPERATURES FOR TODAY AND KNOCKED PRECIPITATION DOWN TO 10 PERCENT ACROSS THE BOARD. BOLDT .LONG TERM...THE EXTENDED MODELS ARE IN A LITTLE BETTER AGREEMENT THIS MORNING AS THE 17/00Z GFS HAS NOW LEANED TOWARD THE EURO SOLUTION. THERE ARE STILL SIGNIFICANT DIFFERENCES AMONG THE MODELS BUT AT LEAST THE EURO/GFS ARE NOT 180 DEGREES OUT OF PHASE LIKE PREVIOUS RUNS. THE EURO IS MORE PROGRESSIVE THAN THE GFS BUT WITH A CUTOFF LOW FCST TO DEVELOP OFF SHORE FROM OREGON BY WEEKS END...THE SLOWER SOLUTION SEEMS MORE PRUDENT. THE GFS SHOWS A RIDGE OVER THE NRN ROCKIES FRI BUT THE EURO PUSHES IT RIGHT OUT. WILL OPT TO KEEP THINGS ON THE DRY SIDE FRI. THE GENERAL TREND OF THE MODELS IS TO BRING A TROF OVER THE WRN CONUS THROUGH NEXT WEEKEND. REGARDLESS OF WHICH MODEL ONE PREFERS...WE LOOK TO BE UNDER MOIST NORTH-NORTHWEST FLOW NEXT WEEKEND INTO EARLY NEXT WEEK. THIS SHOULD KEEP US COLD WITH A CHANCE OF SNOW EACH DAY. WRIGHT .MSO...NONE. ...7-DAY SPOT TEMPS AND POPS... LIB EEB /039 025/033 028/029 2700210 EEEE 012/025 014/025 012/024 012/023 008/ 32004433333 FCA EEB /037 025/032 023/027 2700020 EEEE 010/024 012/024 010/023 010/022 006/ 32014433333 POL EEB /037 028/034 024/029 2710031 EEEE 013/025 015/026 013/024 013/023 009/ 32014433333 MSO EEB /037 023/032 023/028 2710120 EEEE 013/026 015/027 013/025 013/024 009/ 32014433333 HMM EEB /039 026/035 022/028 2712121 EEEE 012/026 013/027 012/025 012/024 008/ 32013333333 BTM BEE /034 005/024 002/021 2710021 EEEE 002/021 004/022 002/020 002/016 902/ 32013343333 ORO EEB /043 030/041 030/041 2710200 EEEE 025/035 026/036 025/034 025/033 021/ 32003333222 GRV MEB /038 026/038 025/037 2711300 EEEE 017/030 018/030 017/029 017/028 013/ 32013333222 SMN BEB /033 012/022 010/023 2710010 EEEE 005/024 006/024 005/023 005/016 001/ 32013333333 mt SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 305 PM CST TUE DEC 17 2002 FORECAST CONCERN CENTERS ON THIS LOW CLOUDS/FOG SITUATION TONIGHT... THEN JUST GENERAL UNSETTLED NATURE OF THE WEATHER NEXT FEW DAYS. DENSE FOG HAS LIFTED ACROSS THE CWFA WITH CURRENT LOWEST VSBYS ACROSS THE FAR NORTH. CLEARING TREND ON SATELLITE OVER THE SOUTHERN 3 TIER OF COUNTIES...AND WORKING AS EVIDENT LOOKING OUTSIDE IF NOTHING ELSE. KHLC LOW DEVELOPING WITH ASSOCIATED WARM FRONT... WITH BIG PRESSURE FALLS CONSISTENTLY ON THE TOP SIDE OF THE FRONT. MID LEVEL PROFILER TRENDS SEEM TO SUPPORT GENERIC MODEL GUIDANCE. IT APPEARS WE WILL ESCAPE THE NEED FOR ANY FOG ADVISORY THIS EVENING. ETA QUICKLY TURNS WINDS TO THE WEST ACROSS THE CWFA BY MIDNIGHT...BUT THE RUC HOLDS BACK THE INVERTED TROUGH AND KEEPS WINDS SSE LONGER AND THUS MORE MOISTURE. IT APPEARS A COMBINATION OF TIMING FROM THE TWO WILL WORK...AND CLEARING WILL WORK ACROSS THE NORTHERN HALF OF THE AREA FROM THIS EVENING TO SHORTLY AFTER MIDNIGHT. RADAR TRENDS INDICATED -DZ TYPE PRECIPITATION IS ALSO LIFTING WELL TO OUR NORTHEAST ATTM. THOUGH INITIAL WAVE SEEMS TO SQUELCHED ANY DEVELOPMENT...ALTHOUGH ELEVATED TYPE CLOUDS ACROSS THE FRONT RANGE SEEM BOTHERSOME. IN GENERAL...WILL KEEP SOME PATCHY FOG EARLY...THEN A SMALL CHANCE EASTERN ZONES FOR SOME CONTINUITY. WITH STRONG UPPER LOW TO OUR NORTH WEDNESDAY...WE HAVE A FAVORABLE PATTERN FOR DOWNWARD MOTION AND WESTERLY FLOW. THAT'S DRY AND OFTEN WARMER THAN EXPECTED. NUMERICAL GUIDANCE SUGGESTS THIS AS WELL AND WILL UP THE TEMPS A BIT WEDNESDAY. NO MAJOR CHANGES TO THE THURSDAY AND FRIDAY TIMEFRAME...ALTHOUGH IT WILL BE WINDY AND COOLER IN GENERAL. THE OVERALL TRENDS FOR DAYS 4-7 ARE HANDLED WELL IN THE CURRENT FORECAST AND WILL MAKE FEW ADJUSTMENTS. ENSEMBLES INDICATE A PERIOD OF WNW NEAR ZONAL TYPE FLOW...WITH A SHIFTING TOWARD MORE OF A SHALLOW LONG-WAVE TROUGH TOWARD WEEKS. SERIES OF IMPULSES WILL PASS THROUGH THE FLOW...BUT LIKELIHOOD ANY SIGNIFICANT PRECIPITATION SEEMS LOW FOR NOW. TEMPERATURE WILL COOL BACK TO NEAR SEASONAL NORMALS AS ALREADY INDICATED. OF INTEREST THOUGH...IS AT LEAST SOME INDICATION OF EITHER A LEAD SHORTWAVE (MRF) OR A POTENTIALLY LARGE TROUGH (ECMWF) PUSHING ONTO THE PLAINS CHRISTMAS EVE AND CHRISTMAS DAY. GIVEN SUCH LATE PROXIMITY IN THE FORECAST AND RESULTANT UNCERTAINTY...WILL NOT INCLUDE ANYTHING JUST YET...BUT SITUATION DOES BEAR CLOSE WATCHING THE NEXT FEW DAYS. .GID...NONE. MORITZ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 255 PM CST TUE DEC 17 2002 ...MAIN CHALLENGE IS POPS NEXT 24 HOURS...AS WELL AS TEMPS... SURFACE ANALYSIS AT 20Z SHOWS DEEPENING LOW PRESSURE OVER HIGH PLAINS WITH 988 CENTER OVER SE COLORADO. WARM FRONT STRETCHED ACROSS NORTHEAST KANSAS AND CENTRAL MISSOURI...WITH SURFACE TEMPERATURES RANGING FROM 60 AT TOPEKA TO 36 AT DENISON IOWA. RUC ANALYZED A 500 MB VORT MAX OF 21 JUST SOUTH OF TOPEKA...OVER THE SURFACE WARM FRONT. SOME DENSE FOG STILL BEING REPORTED IN THE COOL SECTOR NORTH OF THE WARM FRONT...WITH DRIZZLE FALLING AT WFO VALLEY. PROFILERS SHOWED A 90 KNOT 500 MB JET MAX OVER VICI OKLAHOMA AT 20Z...PUSHING A SEMI-CLEARING LINE NORTHEAST THROUGH KANSAS. FORECAST FOR TONIGHT WILL BE A FUNCTION OF VERTICAL MOTION FROM THE VORT MAX...SPEED MAX...AND ISENTROPIC LIFT OVER THE WARM FRONT (IE 295K SURFACE). LOW LEVEL MOISTURE IS PLENTIFUL WITH LOWER 50S DEWPOINTS ADVECTING INTO SE COUNTIES. LAPSE RATES MAY BRIEFLY SUPPORT AN ELEVATED THUNDERSTORM OR TWO...WITH ETA SOUNDING FOR FAIRBURY SHOWING 700-500 LAPSE RATE OF 8.2...BUT NO CONVECTION HAS BEEN ABLE TO DEVELOP THUS FAR OVER KANSAS. WILL WORD TONIGHT AS DRIZZLE AND FOG EARLY WITH AT LEAST A CHANCE FOR SHOWERS MOST AREAS. WILL KEEP THE POSSIBILITY OF A THUNDERSTORM IN SE COUNTIES. LOWS TONIGHT WILL BE DIFFICULT AROUND THE WARM FRONTAL ZONE. EXPECT SOME BREAKS IN THE CLOUDS ESPECIALLY SOUTHERN HALF...BUT DEWPOINTS SHOULD REMAIN QUITE HIGH. LOWS WILL NEED TO RANGE FROM THE LOWER 40S SOUTH TO THE LOWER 30S NORTH. ON WEDNESDAY...THE MODELS ARE NOT IN GREAT AGREEMENT WITH THE MOVEMENT OF THE SURFACE OR UPPER LOW...BUT THE 18Z ETA HAS COME MORE IN LINE WITH THE 12Z GFS. THE UPPER LOW IS PROGGED TO END UP OVER THE EASTERN DAKOTAS WITH THE SURFACE LOW OVER MINNESOTA...THUS CWA WILL BE WELL SOUTH OF THE LOW AND IN WESTERLY FLOW. WOULD BE SURPRISED TO SEE ANY ORGANIZED DEFORMATION ZONE PRECIPITATION REACH AS FAR SOUTH AS NEBRASKA...BUT KEPT ONLY FLURRIES OR LOW POPS IN NORTHERN COUNTIES FOR WEDNESDAY THROUGH THURSDAY. COLD AIR ADVECTION DOES NOT LOOK TOO IMPRESSIVE...AND CLOUDS WILL NOT BE SOLID...SO TEMPERATURES MAY RECOVER IN THE DAYTIME FAIRLY WELL. LEANED TOWARDS WARMER GUIDANCE VALUES FOR HIGHS...BUT GUIDANCE LOWS APPEAR REASONABLE. EXTENDED MODEL SOLUTIONS ARE VERY DIFFERENT...WITH POOR RUN-RUN CONSISTENCY. THUS CONFIDENCE IN DAYS 5-7 IS VERY LOW...ALTHOUGH I DONT SEE A LOT OF SUPPORT FOR A WET PATTERN. MODELS ARE NOT BRINGING IN A SIGNIFICANT UPPER SYSTEM...SO EITHER DRY OR LOW POPS LOOKS LIKE THE BEST FORECAST AT THIS TIME. .OMA...NONE. NIETFELD ne FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 825 PM CST TUE DEC 17 2002 WILL UDPATE AND ISSUE WINTER WEATHER ADVISORY FOR THE REST OF NORTHEAST NORTH DAKOTA AND THE FAR NORTHERN RED RIVER VALLEY. COMPLEX WEATHER PATTERN. WATCHING CLOSELY CURRENT OBS/RADAR AND LOOKS LIKE MAIN SFC LOW STILL IN KANSAS BUT ANOTHER SFC LOW DEVELOPING IN SE NEBRASKA. BROAD SFC TROUGH EXTENDS NORTHWEST INTO SW ND...CLOSER TO DEVELOPING 70H/50H LOW CENTERS. PCPN EXPANDING QUICKLY NORTH-NORTHWEST IN 30-40KT 95-80H FLOW. THIS A BIT QUICKER THAN 12Z MODELS...BUT NOT OVERLY SO. BIG DIFFERENCE IS WHEN COMPARING ACTUAL BIS/ABR/MPX SOUNDINGS TO PROG ETA SOUNDINGS. 12Z ETA WAS TOO WARM AT 85H...ESPCLY AT ABR. ABR 85H TEMP -1 WHERE ETA PROGGED +2. ABR ACTUAL SOUNDING SHOW SLIGHT WARM LAYER NR 820 MB. BUT LOOKING AT OBS...THIS WARM LAYER HAS COOLED WITH ABR SWITCHING OVER TO LIGHT SNOW IN THE PAST HOUR. A QUICK PEEK OF 00Z ETA THROUGH 12Z AND 00Z RUC SHOWS 85H TEMPS COOLING TO -4C OVER ALL OF ERN/CNTRL ND BY 12Z. NOTICED JMS ALSO -SN TOO. THUS HAVE HOPE THAT PD OF FREEZING RAIN WILL NOT BE A LONG AS FEARED. WITH PCPN QUICKLY APPROACHING DVL ZONE WILL NEED TO ADD THEM TO ADVISORY AS PCPN WILL START AT -FZRA BEFORE SWITHCHING TO SNOW. FAR WRN ZONES WILL START SEEING ACCUMULATIONING SNOW OVERNIGHT AND WILL KEEP MENTION OF A FEW INCHES OF ACCUMULATION. PCPN WILL NOT REACH NRN VALLEY TIL LATER TONIGHT BUT AGAIN ICE A FACTOR EARLY SO WILL EXTEND ADVISORY TO PEMBINA/HALLOCK MN AREAS. FOR MN...TEMPS A BIT WARMER BUT INTERESTING IN NOTING THAT SOME OF THE MN AWOS SITES REPORTING -SN IN A WARMER SFC-85H ENVIRONMENT OVER SW MN. NOT SURE IF THIS CORRECT OR A SENSOR ERROR. NONETHELESS WITH COLD CONCRETE SURFACES EVEN 33F AND LIGHT RAIN WILL CAUSE ICING AND WILL KEEP ADVISORY GOING AS KMPX SHOWS PCPN EXPANDING QUICKLY NORTHWARD OUT OF IOWA INTO SRN MN. FOR BDE/ROX ZONES WILL NOT ISSUE ADVISORY AS PCPN WILL BE LAST TO ARRIVE...HOPEFULLY NOT TIL 12Z. WILL KEEP WATCH OUT FOR WED-THU ATTM AS NEW DATA JUST COMING IN. WITH MAIN 50H-70H FEATURES PLAYING A KEY ROLE IN MAIN SNOW AREA. PREV RUNS HAVE THAT CNTRL/WRN ND WED AND THEN OVER ERN ND THU. .FGF...WINTER WEATHER ADVISORY ALL OF ERN ND AND MUCH OF WCNTRL AND NW MN TONIGHT. WINTER STORM WATCH ALL FORECAST AREA WEDNESDAY THROUGH THURSDAY. nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 230 AM EST TUE DEC 17 2002 BROAD LOW PRES OVR THE CENTRAL PLAINS THIS AM WITH WRM FRONT JUST NORTH OF THE FA ATTM. RADAR MOSAICS SHOWING -TSRA OVR IL AND IR PIX SHOW COOLING CLD TOPS AS CONVECTION CONTINUES. MAIN FCST CHALLENGE TDY WL BE POPS. ETA AND AVN AS USUAL PF LATE IN GOOD AGREEMENT EARLY BUT DIVERGE IN THE LATTER PDS. FIRST OFF DEALING WITH THIS AM PCPN OVR IL...RUC AND MESOETA H8-H3 THICKNESS PROPAGATE ALL THIS PCPN ACRS OUR CWA BUT RADAR TRENDS CURRENTLY SUGGEST PCPN BRUSHING MAINLY THE NW PART OF THE CWA. THUS WL KEEP AN EYE ON THE RADAR AND MAY BUMP UP POPS AS -RA TAPERS OFF THIS AM. WL USE LOW POPS SE DUE TO PROXIMITY TO PCPN AND BETTER POPS NW. PROGRESSIVE SW UPPER FLOW TO CONTINUE ACRS INDIANA TDY. THE DIFFERENCE TDY WL MAINLY BE THE LACK OF UPPER SUPPORT. BEST DYNAMICS REMAIN NW OF THE CWA TDY AND THE 300K ISENTROPIC LIFT ALTHOUGH GOOD STARTING OFF THE DAY SLOWLY BECOMES PARALLEL TO THE SFC BY 00Z. THIS SHUD BE EXPECTED WITH THE WAA. WITH WARM FRONT N OF THE FA TDY LOWER CLDS HAVE BEEN ON THE DOWNTREND AND WE SHUD SEE BETTER WARMING AFTER THE MORNING ROUND OF PCPN. NGM SFC TRAJ SHOWS PARCELS ARRVING FM SERN GA WHERE HIGHS TUES WERE IN THE UPPER 50S AND LWR 60S. MORE ACTIVE WX ON TAP TONIGHT AS NEG TITLED UPPER TROF MOVES THROUGH THE FA. WITH ABUNDANT MOISTURE IN PLACE ACRS THE FA ALONG WITH THE FA IN THE LF QUAD OF THE 40-50 KNT LLJ...-TSRA AND -RW LOOK TO BE A GOOD BET. ETA TIME SECTIONS SHOW BEST VV PUSHING THROUGH AROUND 12Z THURS WHILE THE AVN IS A BIT FASTER. AVN PUSHES SFC CD FRONT THROUGH BY 12Z THURS WHILE ETA AGAIN SLOWER. WL WORK A COMPROMISE. DUE TO THIS UNCERTAINTY AND THE WL NEED TO KEEP SOME CHC FOR PCPN ALONG FRONT FOR THURS. AVN H7 RH ALSO SUGGEST SOME BACK EDGE MOISTURE AS FURTHER DEVELOPMENT OCCURS ALONG THE LLJ ACRS KY AND OH. ALL THE MORE REASON TO KEEP SOME POPS IN FOR NOW. THINGS DRY OUT ON THURS NIGHT INTO FRI AS NICE SUBSIDENCE BEGINS TO TAKE SHAPE. AGAIN WITH THE LACK OF DEEP UPPER TROF AND THE NERLY PROGRESSION OF THE UPPER SYS...A MORE OR LESS ZONAL FLOW WL BE LEFT IN THE WAKE OF THE SYS FOR FRI AND NO SURGE OF CD AIR EXPECTED. WL BUMP UP TONIGHT/S LOWS AS WAA SHUD CONT AND LEAN TOWARD WETBULB TEMPS WITH PCPN ONSET. SOME CAA FOR THU...AND CLRING SHOULD NOT TAKE PLACE UNTIL EVE THUS WL LEAN COOLER FROM MAV HIGHS. .IND...NONE. $$ PUMA in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 335 AM CST WED DEC 18 2002 335 AM... BUSY NIGHT WITH STORMS AND VARIOUS WATCHES. MAIN FORECAST CONCERNS ARE IN THE SHORT TERM WITH WATCH IN EFFECT UNTIL 8 AM. RUC MODEL AT 06Z WAS INDICATING DEVELOPMENT OF STORMS IN KANSAS CITY METRO AREA SHORTLY AFTER DAYBREAK AS UPPER LEVEL SHORT WAVE MOVES INTO AREA AND LOW LEVEL MOISTURE IS DRAWN FURTHER NORTH AND WEST JUST AHEAD OF SURFACE FRONT. HOWEVER...BETTER DEEPER MOISTURE WILL REMAIN MORE ACROSS THE SOUTHEAST PART OF OUR FORECAST AREA AS PROFILERS SHOWING 850 WINDS REMAINING FROM THE SOUTHWEST. THUS THINK SCATTERED STORMS AT BEST WHERE MOISTURE IS NOT AS DEEP WITH STORMS MORE LIKELY IN SOUTHEAST PART OF FORECAST AREA WHEN FRONT AND UPPER WAVE ENCOUNTERS 850 MB THETA E AXIS TODAY. MAIN UPPER TROUGH AXIS WILL STAY OVER AREA ON INTO THURSDAY...BUT DRIER AIR WILL BE WRAPPING INTO FORECAST AREA SO AFTER THIS AFTERNOON...EXPECT FORECAST AREA TO REMAIN DRY. FORECAST WILL BE TRICKY AS SHORTWAVES WILL CONTINUE TO ROTATE AROUND UPPER LOW OVER MINNESOTA. MOISTURE WILL REMAIN LIMITED...BUT GFS MODEL PAINTING SOME LIGHT QPF IN SOUTHERN PART OF FORECAST AREA ON SATURDAY AS NORTHERN PLAINS UPPER LOW LIFTS OUT WITH A SHORT WAVE IN SOUTHERN STREAM CUTTING INTO CENTRAL PLAINS AND PHASING WITH A WAVE IN THE NORTHERN STREAM. WILL PUT A SLIGHT CHANCE IN THE GRIDDED DATA FOR RAIN OR SNOW...BUT IN ZONE WORDING WILL KEEP IT DRY AS THERE IS TOO MUCH QUESTION OF TIMING AND MOISTURE AVAILABILITY WITH THESE WAVES. NO REALLY COLD AIR TO SPEAK OF AS CANADIAN AIR REMAINS PRETTY MUCH UNTAPPED AND WESTERLY COMPONENT TO WINDS AROUND NORTHERN PLAINS LOW BRINGS DOWNSLOPE EFFECTS TO HELP MODERATE AIRMASS. PC .EAX... KS...NONE. MO...NONE. mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1052 AM EST TUE DEC 17 2002 MAIN CONCERN WITH THIS FORECAST UPDATE IS THE HEADLINES FOR FREEZING RAIN RAIN. RUC AND THE WATER VAPOR IMAGERY SHOWING A CLOSED LOW OVER THE DAKOTAS EMBEDDED IN A BROAD LONGWAVE TROUGH OVER THE NORTHERN PLAINS AND THE NORTHERN ROCKIES. A STEEP RIDGE STRETCHES ALONG THE ATLANTIC COAST THEN NORTHWEST TO HUDSON BAY. THIS RIDGE IS SLOWING THE EASTWARD PROGRESSION OF THE CLOSED LOW. A SHORTWAVE IS ROTATING AROUND THE BASE OF THIS LOW AND IS RACING THROUGH THE FORECAST AREA THIS MORNING. SURFACE ANALYSIS SHOWING A LOW OVER SOUTHWEST MINNESOTA WITH A COLD FRONT UNFOLDING THROUGH IOWA...INTO THE SOUTHERN PLAINS. KMQT 88D DEPICTING PATCHES OF RAIN OVER MUCH OF THE U.P. THE RAIN IS OCCURRING IN A AREA OF THE BEST ISENTROPIC LIFT AHEAD OF THE APPROACHING COLD FRONT. A WARM FRONT IS LEADING THE MINNESOTA LOW...AND IS JUST TO THE SOUTH OF THE FORECAST AREA. WARM AIR OVER RUNNING THIS FRONT WAS PRODUCING THE WARM AIR ABOVE THE SURFACE...WHILE SURFACE TEMPERATURES REMAIN NEAR FREEZING PRODUCING THE FREEZING RAIN. WARM AIR ADVECTION AND AN INCREASE IN GULF MOSITURE OVER THE FORECAST AREA THIS AFTERNOON WILL BE A RESULT OF A LOW LEVEL JET BLOWING THROUGH THE MID MISSISSIPPI VALLEY INTO THE UPPER GREAT LAKES. AT 15Z NEARLY ALL SURFACE REPORTING STATIONS OVER THE U.P. ARE REPORTING AT OR ABOVE FREEZING TEMPERATURES. IT IS TIME TO DROP THE FREEZING RAIN WARNING. THE LOW LEVEL JET OVER THE FORECAST AREA WILL MIX DOWN TO SURFACE MAINLY OVER THE EASTERN PART OF LAKE SUPERIOR THROUGH THE AFTERNOON AND TONIGHT...DUE TO THE WARM TEMPERATURES OF THE LAKE. THIS STILL WARRANTS THE NEED FOR GALE WARNGS. PLAN TO LEAVE THE REAST ALONE FOR THE TIME BEING. .MQT...GALE WARNING EAST 2/3 LAKE SUPERIOR DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 500 AM CST WED DEC 18 2002 NUMEROUS SHRA AND TSRA CONT TO DVLP OVR CNTRL AND NERN MO AHD OF STG SHRTWV TROF MOVG NEWD THRU ERN KS. TSRA ACRS SWRN MO APR TO HAVE WKND SOME AND HAVE BCM LESS NUMEROUS. FOCUS FOR NEW TSRA DVLPNT THIS MRNG MAY BE ACRS NERN MO W CNTRL IL AS LATEST RUC SHOWS STGST 850 MB MOISTURE CNVG AND THETA E ADVCTN ON NOSE OF STG 50 KT SWLY LLJ IN THIS AREA. POTENTIAL FOR SHRA AND TSRA SHOULD SLOWLY SHIFT EWD BY THIS AFTN AND EVNG AS LLJ AND ASSOCIATED TEMP AND THETA E ADVCTN TRANSLATES EWD INTO IL WITH DRIER 850 MB DWPTS PUSHING INTO THE NRN AND WRN PTNS OF THE CWA. ETA MDL CONTS TO INDICATE RELATIVELY STG UPR DIVERGENCE S AND E OF STL TGT AND WILL PUT HIGHEST POPS OVR ERN AND SRN PTNS OF THE CWA TGT. DIFFICULT TO FIND SFC CDFNT IN SFC WND FIELD WITH ONLY A GRADUAL VEERING OF THE WNDS. BASED ON ETA SFC DWPT ANALYS IT APRS THE CDFNT WILL PUSH SEWD THRU STL DURG THE EVNG HOURS AND SHOULD BE SE OF THE ENTR CWA ARND 12Z THU WITH SFC DWPTS DROPPING INTO THE 30S OVR THE NRN AND WRN PTNS OF THE CWA...ALTHOUGH COLDER AIR LAGGING WELL BHND THE CDFNT ON THE ETA MDL. TIME SECTIONS ON THE MDLS SHOW GOOD DRYING OF THE LOW-MID LVL MOISTURE LTR TGT AND EARLY THU. MAV AND FWC MOS GUIDANCE MAY HAVE TOO MUCH CLOUD CVR ON THU AND WILL LEAN TOWARD MET GUIDANCE...ALTHOUGH NOT AS WRM AS ITS HI TEMPS. .STL...NONE GKS mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 445 PM EST WED DEC 18 2002 CONCERNS DEAL WITH CHCS OF -RA TONIGHT INTO ERY THU...THEN SNOW CHCS THRU REST OF FCST PDS. MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE RAIN FOR TONIGHT AND RAIN CHANGING TO SNOW ON THURSDAY. RUC AND THE WATER VAPOR IMAGERY SHOWING A LOW OVER EASTERN DAKOTAS EMBEDDED IN A LONGWAVE TROUGH OVER THE NORTHERN PLAINS. A SHORTWAVE IS ROTATING THROUGH THE BASE OF THIS LOW AND IS SPEEDING THROUGH IOWA INTO WISCONSIN. A COLD FRONT STRETCHES FROM A LOW OVER NORTHERN MINNESOTA IS MOVING INTO WESTERN WISCONSIN...WHILE A WARM FRONT LEADING THE LOW IS EDGING INTO SOUTHERN PART OF THE FORECAST AREA. WARM MOIST AIR IS ADVECTING INTO THE AREA ON THE NOSE OF A 45 KNOT LOW LEVEL JET RACING NORTHEAST THROUGH ILLINOIS AND NORTHERN LOWER MICHIGAN. ISENTROPIC LIFT AHEAD OF THE COLD FRONT AND OVER RUNNING OF THE WARM FRONT IS KEEP RAINS ACTIVE OVER THE AREA. TEMPERATURES HAVE CLIMBED INTO THE LOW 40S OVER THE SOUTHERN U.P. AND ELSEWHERE TEMPERATURES ARE IN THE MID AND UPPER 30S. THE UPPER LEVEL LOW WILL REACH THE LAKE OF THE WOODS AREA BY THURSDAY MORNING. A COUPLE OF SHORTWAVES WILL MOVE ACROSS THE FORECAST AREA OVERNIGHT...PRODUCING Q-VECTOR CONVERGENCE OVER THE AREA OVERNIGHT. THESE HAVE BEEN PRODUCING A FEW THUNDERSTORMS JUST SOUTH OF THE WARM FRONT TODAY. AFTER THE WARM FRONT MOVES THROUGH TONIGHT...AN ISOLATED THUNDERSTORM IS POSSIBLE OVER FAR EASTERN U.P. LATE TONIGHT. THE WARM MOIST AIR ALONG WITH THE RAIN THAT FELL TODAY HAS ALREADY STARTED PRODUCING AREA OF FOG AND MIST ACROSS THE FORECAST AREA AND THIS SHOULD CONTINUE OVERNIGHT. CLOUD COVER AND WARM AIR ADVECTION WILL KEEP TEMPERATURES NEARLY STEADY AROUND 40 OVERNIGHT. WINDS WILL CONTINUE OUT OF THE SOUTH TONIGHT...VEERING WEST FOLLOWING THE FROPA'S. THE WARM LAKE WILL AID MIXING PART OF THE LOW LEVEL JET TO SURFACE OVER THE EASTERN LAKE. THUS WILL KEEP THE GALES UP THROUGH THIS EVENING. DLG THU...CONVERGENCE ALG LINGERING CDFNT OVR ERN COUNTIES AND DIV IN LEFT EXIT REGION OF 140+ KT JET MAX MOVG THRU LWR MIDWEST WILL ALLOW FOR LINGERING -SHRA OVR ERN COUNTIES IN THE MORNING HRS. AS SHRTWV/SPEED MAX LIFTS CDFNT TO EAST IN AFT LOOK FOR SHRA TO END OVR ERN COUNTIES. SHRTWV LOBE FM CLOSED LOW TO WEST WILL THEN PROPEL SECONDARY CDFNT INTO WRN ZONES LATE IN DAY AND BRING CHC OF -SHSN. SECONDARY CDFNT WILL CONTINUE EAST ACROSS CWA THU NIGHT WITH DRIER AND COOLER CONDS INTO FRI. LINGERING UPR LOW OVR AREA WILL WARRANT KEEPING LOW CHC POPS FOR INSTABILITY -SHSN IN FCST. 850 MB TEMPS OF -7C TO -8C SHOULD PROHIBIT LES THOUGH. .FRI NIGHT INTO SAT...MODELS INDICATE YET ANOTHER SHRTWV ON BACK SIDE OF UPR LOW TO MOVE THRU CWA LATE FRI NIGHT BRINGING IN ANOTHER SHOT OF COLDER AIR. 850 MB TEMPS LWR TO -10 TO -12C OVR LAKE SUPERIOR WITH GOOD CYCLONIC WNW FLOW NOTED. GIVEN BETTER CHC OF LAKE EFFECT OR LAKE ENHANCED SNOW DVLPG WITH LAKE DELTA-T'S RISING TO 13-15C HAVE BUMPED UP POPS TO LIKELY FOR FAVORED WNW FETCH AREAS OF ONT-CMX-KEW AND ALGER-LUCE-NRN SCHOOLCRAFT FOR LATE FRIDAY NIGHT INTO SAT. .EXTENDED...MEDIUM RANGE MODELS SHOW CONTINUED CAA BEHIND LINGERING LOW OVR HUDSON BAY SUN INTO MON AS 850 MB TEMPS LWR TO -14 TO -16C IN NW FLOW SO WL CONTINUE MENTION OF NUMEROUS LAKE EFFECT -SHSN FOR NW AND ERN ZONES ALG LAKE SUPERIOR INTO THE ERY PART OF WEEK. MODELS IN AGREEMENT WITH UPR LOW OVR HUDSON BAY LIFTING NE BY TUE INTO WED BUT OPERATIONAL RUNS STILL INDICATE SERIES OF WAVES TO MOVE IN FM WEST FOR MID WEEK. ENSEMBLE MEMBERS ALSO SUPPORT UNSTABLE WLY FLOW SO WL LEAVE CHC OF -SHSN FOR NOW. COORD WITH APX...THANKS. .MQT...GALE WARNING EAST 2/3 LAKE SUPERIOR. VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 318 PM CST WED DEC 18 2002 THE MAIN FOCUS FOR THIS PACKAGE WILL FOCUS ON THE BENIGN WEATHER THAT WILL PREVAIL ACROSS THE REGION FOR THE NEXT FEW DAYS. NOT MUCH TO TALK ABOUT AS THE ACTIVE WEATHER HAS PUSHED TO THE EAST. OUR DRYLINE HAS PUSHED THROUGH MOST OF THE COUNTY WARNING AREA THIS AFTERNOON ELIMINATING ANY LINGER CHANCE FOR THUNDERSTORM ACTIVITY. THE MID CONTINENTAL TROUGH AXIS WILL CONTINUE TO DEEPEN AND SLIDE EAST THROUGH FRIDAY WITH THE HELP A SHORTWAVES ROTATING AROUND THE GREAT LAKES UPPER LEVEL LOW. THIS WILL LEAVE EAST KANSAS AND NORTHERN MISSOURI DOMINATED BY A DRY NORTHWEST FLOW THROUGH THE BEGINNING OF THE THE WEEKEND. TEMPERATURES ARE EXPECTED TO REMAIN A CATEGORY OR TWO ABOVE NORMAL THROUGH THE LAST HALF OF THE WORK WEEK AS SURFACE WINDS REMAIN OUT OF THE WEST AND THE COOLEST AIR REMAINS TO OUR NORTH WRAPPED UP IN THE BASE OF THE CONTINENTAL TROUGH. AS FOR THE EXTENDED...NO SIGNIFICANT CHANGES WERE MADE. CUTTER 335 AM... BUSY NIGHT WITH STORMS AND VARIOUS WATCHES. MAIN FORECAST CONCERNS ARE IN THE SHORT TERM WITH WATCH IN EFFECT UNTIL 8 AM. RUC MODEL AT 06Z WAS INDICATING DEVELOPMENT OF STORMS IN KANSAS CITY METRO AREA SHORTLY AFTER DAYBREAK AS UPPER LEVEL SHORT WAVE MOVES INTO AREA AND LOW LEVEL MOISTURE IS DRAWN FURTHER NORTH AND WEST JUST AHEAD OF SURFACE FRONT. HOWEVER...BETTER DEEPER MOISTURE WILL REMAIN MORE ACROSS THE SOUTHEAST PART OF OUR FORECAST AREA AS PROFILERS SHOWING 850 WINDS REMAINING FROM THE SOUTHWEST. THUS THINK SCATTERED STORMS AT BEST WHERE MOISTURE IS NOT AS DEEP WITH STORMS MORE LIKELY IN SOUTHEAST PART OF FORECAST AREA WHEN FRONT AND UPPER WAVE ENCOUNTERS 850 MB THETA E AXIS TODAY. MAIN UPPER TROUGH AXIS WILL STAY OVER AREA ON INTO THURSDAY...BUT DRIER AIR WILL BE WRAPPING INTO FORECAST AREA SO AFTER THIS AFTERNOON...EXPECT FORECAST AREA TO REMAIN DRY. FORECAST WILL BE TRICKY AS SHORTWAVES WILL CONTINUE TO ROTATE AROUND UPPER LOW OVER MINNESOTA. MOISTURE WILL REMAIN LIMITED...BUT GFS MODEL PAINTING SOME LIGHT QPF IN SOUTHERN PART OF FORECAST AREA ON SATURDAY AS NORTHERN PLAINS UPPER LOW LIFTS OUT WITH A SHORT WAVE IN SOUTHERN STREAM CUTTING INTO CENTRAL PLAINS AND PHASING WITH A WAVE IN THE NORTHERN STREAM. WILL PUT A SLIGHT CHANCE IN THE GRIDDED DATA FOR RAIN OR SNOW...BUT IN ZONE WORDING WILL KEEP IT DRY AS THERE IS TOO MUCH QUESTION OF TIMING AND MOISTURE AVAILABILITY WITH THESE WAVES. NO REALLY COLD AIR TO SPEAK OF AS CANADIAN AIR REMAINS PRETTY MUCH UNTAPPED AND WESTERLY COMPONENT TO WINDS AROUND NORTHERN PLAINS LOW BRINGS DOWNSLOPE EFFECTS TO HELP MODERATE AIRMASS. PC .EAX... KS...NONE. MO...NONE. mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 235 PM CST WED DEC 18 2002 TEMPERATURES WILL BE THE PRIMARY CONCERN THE NEXT SEVERAL DAYS... AND EVEN INTO NEXT WEEK. SURFACE ANALYSIS EARLY THIS AFTN SHOWED LOW PRES CENTER OVER SRN MN...WHICH WILL MOVE NWD INTO CANADA BY LATE TNGT. CDFNT TRAILED SWD FROM THE LOW ACROSS IA...MO...ERN OK AND INTO TX. MAIN JET CORE FROM WATER VAPOR IMAGERY AND LATEST RUC OUTPUT INDICATED UPPER TROPOSPHERIC JET CORE CONTINUED FROM NRN BAJA CA-TX PNHDL-ERN IA. WRN EDGE OF CLOUDS HAS BEEN MOVING EWD AND EXPECT THESE TO DECREASE TNGT. SOME MID AND HIGH CLOUDS LIKELY TO MOVE BACK IN DURING THE NIGHT. WENT PRETTY CLOSE TO THE NGM MOS NUMBERS FOR TNGT. TEMPERATURES UPSTREAM ARE NOT ALL THAT COLD...AND EXPECT SOME MIXING TO CONTINUE DURING THE NIGHT WITH DECENT NWLY GRADIENT. MODELS REMAIN IN GOOD AGREEMENT WITH OVERALL PATTERN INTO SAT... THEN DIFFERENCES BECOME A LITTLE MORE OBVIOUS. MIXING WILL BE RATHER GOOD DURING THE DAYTIME HOURS BOTH THU AND FRI...SO LEFT HIGHS IN THE 40S BOTH DAYS. CLOSED LOW THAT IS CURRENTLY EJECTING NEWD FROM THE PLAINS MOVES EWD ACROSS CANADA FRI AND SAT. ETA HAS A BIT MORE NRLY COMPONENT BY SAT WHILE THE GFS IS PRETTY MUCH ZONAL OVER THE FCST AREA. THIS IS NOT SIGNIFICANT...BUT TREND WILL HAVE TO BE MONITORED. THERE IS SOME SMALL CHANCE OF PCPN ON SAT ACROSS THE NRN ZONES...BUT FOR NOW WILL LEAVE POPS BLO 20 PERCENT. SEE LITTLE CHANCE OF SEEING MUCH SNOW IN OMA OR LNK IN THE NEXT 7 DAYS. MIGHT SEE A LITTLE LIGHT SNOW OVER NERN NE BY WED. .OMA...NONE. MILLER ne