AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LITTLE ROCK AR 630 AM CST TUE DEC 24 2002 UPDATE TO THE UPDATE...WINTER PRECIP IS ONCE AGAIN BREAKING OUT AND INCREASING IN COVERAGE OVER NORTHWEST AR AND NORTHEAST OK. RECENT RUNS OF THE RUC HAVE BEEN HANDLING THIS MUCH BETTER THAN THE 06Z MESOETA. WILL HOIST WINTER WEATHER ADVISORY FOR NORTHWEST COUNTIES WHERE PRECIP HAS BEGUN AS FREEZING RAIN...BUT RUC CROSS SECTIONS INDICATE A CHANGE TO ALL SNOW DURING THE MORNING. EXPECT ANOTHER ONE TO TWO INCHES BY THE TIME ITS ALL SAID AND DONE. UPDATE...CALLS TO NORTHERN COUNTIES INDICATE LIGHT RAIN FALLING. ONLY STATIONS AT OR BELOW FREEZING ARE KBPK AT 31 AND KHRO AT 30. DESPITE THE -FZRA REPORTED AT KHRO...LAW ENFORCEMENT SAYS NO PROBLEMS AT THIS TIME AND SNOW HAS MELTED OUT OF THEIR PARKING LOT. WILL LET THE WINTER STORM WARNING AND WINTER WEATHER ADVISORY EXPIRE. AS GUESSED EARLIER...STEADY RAIN EXITED SOUTHEAST ZONES ABOUT 0915Z. SO THE FLASH FLOOD WATCH WILL ALSO BE ALLOWED TO EXPIRE. AND THE NUMBERS... LIT 38 26 43 26 38 41111 HOT 38 26 44 27 39 33111 HRO 31 14 40 17 36 41111 PBF 40 27 44 27 39 33111 PREVIOUS DISCUSSION... FORECAST CHALLENGES COME IN THE FIRST TWO PERIODS. QUESTIONS INCLUDE HOW MUCH MORE RAIN IN SOUTHEAST AR...HOW MUCH MORE SNOW IN NORTH AR...WHETHER OR NOT IT WILL SNOW IN CENTRAL/SOUTH AR...AND WHEN THE CLOUDS WILL CLEAR OUT. FOR SOUTHEAST AR...THE POWERFUL STORM COMPLEX OVER LA/MS IS FINALLY TAKING ITS TOLL BY DISRUPTING THE INFLOW ABOVE THE BOUNDARY LAYER. MODELS HAVE NO CLUE ABOUT THIS...BUT THE RAPID EROSION OF THE SOUTHWEST EDGE OF THE PRECIP SHIELD IS A DEAD GIVEAWAY. EXTRAPOLATION OF BACK EDGE OF PRECIP DEPICTED ON KSHV RADAR SUGGESTS RAIN WILL END IN OUR SOUTHEAST ZONES AROUND 10Z...OR RIGHT ABOUT PRESS TIME. MORNING POPS FOR THIS AREA WILL BE A LAST MINUTE CALL. SHOULD BE ABLE TO LET FLASH FLOOD WATCH EXPIRE ALSO BUT THIS CALL IS SUBJECT TO LAST MINUTE OVERTURNING. FOR NORTH AR...DYNAMIC FORCING HAS REACHED A MAXIMUM AND SHOULD BE ON THE DECREASE OVER THE NEXT FEW HOURS. THE INFLOW DISRUPTION EFFECTS OF THE STORMS FARTHER SOUTH WILL TAKE A LITTLE LONGER TO REACH THIS AREA...BUT RADAR AND SATELLITE TRENDS SUGGEST THAT SIGNIFICANT PRECIP WILL END IN THE NORTHWEST AROUND 10Z AND PERSIST A LITTLE LONGER THAN THAT IN THE NORTHEAST. MAY BE ABLE TO LET THE WINTER STORM WARNING AND WINTER WEATHER ADVISORY EXPIRE AT 10Z...BUT WILL MAKE FINAL DECISION BASED ON RADAR TRENDS AND RESULTS OF PHONE CALLS TO AREA LAW ENFORCEMENT OFFICIALS AFTER 09Z. SNOW POTENTIAL IN CENTRAL AND SOUTH AR IS MINIMAL BUT NONZERO. NUMERICAL MODEL OUTPUT SUGGESTS A GOOD CHANCE OF SNOW THIS AFTERNOON...BUT THE AFOREMENTIONED INFLOW DISRUPTION WILL PLAY A MITIGATING ROLE. 00Z MESOETA ISENTROPIC PROGS SHOW A BRIEF PERIOD DURING THE AFTERNOON OF SHARP RISES ON THE 275-285K SURFACES WHICH SHOULD BE ENOUGH TO OFFSET DOWNGLIDE. THIS SHORT BURST OF UPWARD MOTION MAY WRING OUT A LITTLE BIT OF SNOW SINCE LOW LEVEL MOISTURE WILL STILL BE LINGERING AROUND...BUT AMOUNTS WILL BE MINIMAL. 06Z MESOETA JUST CAME IN AND IT ALSO SHOWS THE SHARP RISE MOVING FROM NORTH AR TO SOUTH AR BETWEEN 21Z AND 03Z. CLOUDS WILL CLEAR OUT WHEN LOW LEVEL THERMAL TROUGH MOVES THROUGH AND ISENTROPIC SURFACES BEGIN TO SINK RATHER THAN RISE. 00Z MESOETA SHOWED THIS OCCURRING OVERNIGHT TONIGHT. 06Z RUN IS A LITTLE SLOWER AND HINTS AT SOME STRATUS HANGING AROUND IN THE NORTHEAST THROUGH CHRISTMAS MORNING. HAVE NOT LOOKED AT TEMPS YET DUE TO FLOODING AND WINTER WEATHER CONCERNS. WILL ISSUE UPDATED AFD INCLUDING TEMPS/POPS AND ADVISORIES IF ANY AROUND 4 AM. NO CHANGES PLANNED FOR THURSDAY AND BEYOND. FOCUS IS ON THE FIRST TWO DAYS OF THIS PACKAGE. .LZK...WINTER WEATHER ADVISORY TODAY ARZ003>005-012-013. $$ 54 ar EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 853 PM EST TUE DEC 24 2002 CURRENT WEATHER...COMPOSITE RADAR MOSAIC SHOWING LARGE AREA OF SHOWERS AND THUNDERSTORMS MOVING ACROSS CENTRAL FLORIDA AT 40 MPH. MOST OF THE HEAVY RAIN WAS OCCURRING/HAD OCCURRED IN VOLUSIA COUNTY WHERE OVER TWO INCHES OF RAIN HAS FALLEN THE PAST FEW HOURS. THE MAIN COLD FRONT WAS STILL BACK OVER THE GULF OF MEXICO APPROACHING 85W AND MOVING EAST AT 25 TO 30 MPH. EARLY UPDATE TO THE ZONES TO REMOVE THE TORNADO WATCH...BUT LEFT MENTION OF POSSIBLY A STRONG STORM. LATEST RUC UPPER AIR ANALYSIS AND PROG SERIES SHOW A 180 KT PLUS H25 JET MAX MOVING ACROSS GULF COAST. ALTHOUGH THE UPPER SUPPORT WAS NORTH OF THE AREA...RATHER STRONG LOW LEVEL FLOW AND GOOD MOISTURE (DEWPOINTS AROUND 70) SHOULD CONTINUE TO SUPPORT SCATTERED SHOWERS AND STORMS. DEAD RECKON TRACKING OF THE AREA OF STORMS AND SHOWERS STARTS CLEARING THEM OUT IN THE NORTHERN ZONES AROUND MIDNIGHT AND EXITING THE SOUTHERN FORECAST AREA TOWARD SUNRISE. WILL WATCH THIS TREND FOR ANOTHER HOUR OR SO BEFORE ISSUING ANY UPDATE. APPEAR TO BE TRANSITIONING TO A BRIEF PERIOD OF HEAVY RAIN POTENTIAL AS CONVECTIVE LINE WAS STRINGING OUT MORE WEST/EAST. BUOY 009 RECORDING NORTHEAST WINDS AT 16 KNOTS DUE TO STORMS IN THE AREA. EXPECT THAT THE WINDS WILL PICK UP MORE AS THE NEXT AREA OF SHOWERS AND STORMS MOVES ACROSS THE COASTAL WATERS. BUOYS IN THE NORTHWEST AND NORTH GULF OF MEXICO...WHERE THE FRONT ALREADY PASSED THROUGH...WERE RECORDING NORTHWEST WINDS AT 25 TO 30 KNOTS. TOMORROWS FORECAST MATCHES UP WELL WITH THESE WINDS. .MLB...SMALL CRAFT ADVISORY FLAGLER BEACH TO JUPITER INLET. ...FIRE WEATHER WATCH WEDNESDAY LAKE/VOLUSIA/SEMINOLE/ ORANGE AND NORTHERN BREVARD COUNTIES. PUBLIC/MARINE...WIMMER AVIATION/FIRE WX...LASCODY fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 955 AM EST TUE DEC 24 2002 HAV UPDATED ZONES AND COASTAL WATERS FORECASTS FOR TORNADO WATCH #806. SCA CONDITIONS UNDERWAY OVER ALL OF COASTAL WATERS. WE HAVE RECEIVED MANY REPORTS OF TORNADOES AND DAMAGE THAT WILL BE ISSUED SHORTLY IN A LOCAL STORM REPORT. .TLH... AL...NONE. GA...NONE. FL...SMALL CRAFT ADVISORY ALL MARINE ZONES. TJT PREVIOUS DISCUSSION FOLLOWS. ***************************************************************** 620 AM EST TUE DEC 24 2002 WILL BE UPDATING ZONES AND COASTAL WATERS FORECASTS FOR SHORTLY FOR TORNADO WATCH #805. LAPS ANALYSIS SHOWS INCREASING SURFACE BASED CAPE WORKING E INTO OUR WRN CWFA WHILE KEOX AND KEVX VAD WIND PROFILES ALREADY SHOW IMPRESSIVE 0-1KM SHEAR ALREADY UNDERWAY. .TLH... AL...NONE. GA...NONE. FL...SMALL CRAFT ADVISORY ALL MARINE ZONES. PREVIOUS DISCUSSION FOLLOWS. ***************************************************************** 300 AM EST TUE DEC 24 2002 FORECAST CHALLENGE -- POSSIBLE SEVERE WEATHER. --SYNOPSIS-- WATER VAPOR IMAGES SHOW UPPER JET LIFTING ACROSS TX AROUND BASE OF BROADENING UPPER TROUGH. STRONG/SEVERE CONVECTION ONGOING OVER MS/LA/ERN TX BENEATH EXIT REGION OF THIS JET. 05Z SURFACE ANALYSIS SHOWED LOW OVER LA WITH WARM FRONT AHEAD OF THIS LOW LIFTING OVER CENTRAL MS/AL/GA. OUR LOCAL BUOYS ARE REPORTING DEWPOINTS IN THE LOW/MID 60S (F) SO MOIST RETURN SHOULD CONTINUE OVER THE CWFA. A VERY IMPRESSIVE 24/00Z SOUNDING WAS TAKEN AT NEW ORLEANS WITH AN UNMODIFIED 0-3 KM SR HELICITY OF 1069 J/KG. THE TLH SOUNDING WAS NOT NEARLY SO IMPRESSIVE...BUT DID SHOW INCREASING LOWER TROPOSPHERIC FLOW AND STEEPER MID-LEVEL LAPSE RATES. --FORECAST-- MODEL PROGS ON TIMING OF FRONT AND ASSOCIATED CONVECTION REMAINS UNCHANGED FROM PREVIOUS FORECAST...SO VERY FEW CHANGES WERE MADE IN THE ZFP. MENTIONED POSSIBLE SEVERE FOR THE FIRST PERIOD DUE TO STRONG LOWER TROPOSPHERIC WIND PROFILE. AS NOTED IN LATEST SWODY1... PROGGED VERTICAL WIND FIELDS LOOKING MORE UNIDIRECTIONAL THIS AFTERNOON...AND BOUNDARY LAYER TO 6KM SHEAR IS MARKEDLY DECREASED... SO PRIMARY THREAT LOOKS LIKE DAMAGING WIND GUSTS. NONETHELESS...06Z RUC FORECAST SOUNDINGS INDICATE VERY IMPRESSIVE 30-40KT 0-1KM SHEAR OVER OUR SE AL ZONES THIS AFTERNOON...SUGGESTING BOW ECHO ASSOCIATED TORNADOES REMAIN A DISTINCT POSSIBILITY. KEPT THE SAME CARRY-OVER POPS FOR TONIGHT. FIRE WEATHER - NO HIGHLIGHTS. MARINE - ALREADY AT SCA CRITERIA OVER OUR WATERS W OF AAF. EXPECT THE SAME SHORTLY E OF AAF SO HAVE WORDED ACCORDINGLY. FEW CHANGES WERE MADE TO THE COASTAL WATERS FORECAST EXCEPT FOR SOME MINOR FIRST PERIOD ADJUSTMENTS. EXTENDED - NO CHANGES MADE. PRELIMINARY NUMBERS... TLH 073/050 056/029 +500 PFN 071/048 055/035 +300 DHN 069/044 049/030 +300 ABY 068/046 052/030 +400 VLD 072/052 056/030 +500 CTY 076/054 060/030 8600 .TLH... AL...NONE. GA...NONE. FL...SMALL CRAFT ADVISORY ALL MARINE ZONES. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 620 AM EST TUE DEC 24 2002 WILL BE UPDATING ZONES AND COASTAL WATERS FORECASTS FOR SHORTLY FOR TORNADO WATCH #805. LAPS ANALYSIS SHOWS INCREASING SURFACE BASED CAPE WORKING E INTO OUR WRN CWFA WHILE KEOX AND KEVX VAD WIND PROFILES ALREADY SHOW IMPRESSIVE 0-1KM SHEAR ALREADY UNDERWAY. .TLH... AL...NONE. GA...NONE. FL...SMALL CRAFT ADVISORY ALL MARINE ZONES. PREVIOUS DISCUSSION FOLLOWS. ***************************************************************** 300 AM EST TUE DEC 24 2002 FORECAST CHALLENGE -- POSSIBLE SEVERE WEATHER. --SYNOPSIS-- WATER VAPOR IMAGES SHOW UPPER JET LIFTING ACROSS TX AROUND BASE OF BROADENING UPPER TROUGH. STRONG/SEVERE CONVECTION ONGOING OVER MS/LA/ERN TX BENEATH EXIT REGION OF THIS JET. 05Z SURFACE ANALYSIS SHOWED LOW OVER LA WITH WARM FRONT AHEAD OF THIS LOW LIFTING OVER CENTRAL MS/AL/GA. OUR LOCAL BUOYS ARE REPORTING DEWPOINTS IN THE LOW/MID 60S (F) SO MOIST RETURN SHOULD CONTINUE OVER THE CWFA. A VERY IMPRESSIVE 24/00Z SOUNDING WAS TAKEN AT NEW ORLEANS WITH AN UNMODIFIED 0-3 KM SR HELICITY OF 1069 J/KG. THE TLH SOUNDING WAS NOT NEARLY SO IMPRESSIVE...BUT DID SHOW INCREASING LOWER TROPOSPHERIC FLOW AND STEEPER MID-LEVEL LAPSE RATES. --FORECAST-- MODEL PROGS ON TIMING OF FRONT AND ASSOCIATED CONVECTION REMAINS UNCHANGED FROM PREVIOUS FORECAST...SO VERY FEW CHANGES WERE MADE IN THE ZFP. MENTIONED POSSIBLE SEVERE FOR THE FIRST PERIOD DUE TO STRONG LOWER TROPOSPHERIC WIND PROFILE. AS NOTED IN LATEST SWODY1... PROGGED VERTICAL WIND FIELDS LOOKING MORE UNIDIRECTIONAL THIS AFTERNOON...AND BOUNDARY LAYER TO 6KM SHEAR IS MARKEDLY DECREASED... SO PRIMARY THREAT LOOKS LIKE DAMAGING WIND GUSTS. NONETHELESS...06Z RUC FORECAST SOUNDINGS INDICATE VERY IMPRESSIVE 30-40KT 0-1KM SHEAR OVER OUR SE AL ZONES THIS AFTERNOON...SUGGESTING BOW ECHO ASSOCIATED TORNADOES REMAIN A DISTINCT POSSIBILITY. KEPT THE SAME CARRY-OVER POPS FOR TONIGHT. FIRE WEATHER - NO HIGHLIGHTS. MARINE - ALREADY AT SCA CRITERIA OVER OUR WATERS W OF AAF. EXPECT THE SAME SHORTLY E OF AAF SO HAVE WORDED ACCORDINGLY. FEW CHANGES WERE MADE TO THE COASTAL WATERS FORECAST EXCEPT FOR SOME MINOR FIRST PERIOD ADJUSTMENTS. EXTENDED - NO CHANGES MADE. PRELIMINARY NUMBERS... TLH 073/050 056/029 +500 PFN 071/048 055/035 +300 DHN 069/044 049/030 +300 ABY 068/046 052/030 +400 VLD 072/052 056/030 +500 CTY 076/054 060/030 8600 .TLH... AL...NONE. GA...NONE. FL...SMALL CRAFT ADVISORY ALL MARINE ZONES. TJT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 1030 AM CST TUE DEC 24 2002 UPDATE DISCUSSION LATEST SATELLITE...OBS AND PROFILERS SUPPORT RADAR TRENDS OF SYSTEM SPIN UP AS QUICK OR ACTUALLY A TAD QUICKER THAN 12Z MODELS WHICH LATEST 15 RUC ALSO SUGGEST. THIS WILL THROW WRAPAROUND PRECIPITATION AND DEFORMATION ZONE INTO FAR SOUTHEAST ZONES BY MID TO LATE PM PER AWIPS DISTANCE TIME FEATURE. PLAN TO UPDATE SE ZONES FOR HIGHER POPS OF LIKELY WITH MINOR SNOW ACCUMULATIONS. MAY ADD SOME FLURRIES SLIGHTLY FURTHER NORTH AS WELL. EXPECT UPDATED ZONES OUT BEFORE 11 AM CST. IA...NONE. IL...NONE. MO...NONE. NICHOLS il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 227 PM MST TUE DEC 24 2002 FORECAST CONCERNS WILL BE TEMPERATURES THROUGH THE PERIOD. SATELLITE AMPLIFIED FLOW FROM THE CENTRAL PACIFIC INTO NORTH AMERICA. SYSTEM THAT BROUGH SNOW TO SOUTHERN PORTIONS OF THE AREA IS MOVING TO THE EAST. AT JET LEVEL...IF ESTIMATES OF THE SPEEDS ARE CORRECT OUT OVER THE PACIFIC THEN THEN THE NGM IS 20 TO 30 KNOTS LOW WHILE THE ETA/AVN ARE DOING BETTER BUT STILL A TAD LOW. AT MID LEVELS...OVERALL THE MODELS WERE NOT SHARP ENOUGH WITH THE RIDGE IN THE WEST WITH THE ETA DOING BEST. THE ETA/RUC ARE DOING BETTER THROUGH SIX HOURS ON UPPER SYSTEM NOW MOVING INTO THE WYOMING. INITIALLY THE ETA LOOKED BETTER WITH HEIGHT FIELD AT 50H OVER THE CENTRAL PLAINS. HOWEVER...BY 18Z THE ETA STILL HAD EXITING UPPER LOW IN EASTERN KANSAS WHERE REST OF MODELS WERE IN CENTRAL MISSOURI. CIRCULATION LOOKS A LITTLE SOUTH OF THAT. HOWEVER...BY 00Z THE ALL THE MODELS ARE IDENTICAL WITH THE EXITING SYSTEM. AT LOW LEVELS...ETA AND AVN DID BEST WITHE ETA DOING SLIGHTLY BETTER OVER OUR AREA. EVEN THOUGH ETA IS HAVING ITS PROBLEMS INITIALLY WITH UPPER SYSTEM TO OUR EAST...WILL USE IT BASED ON A BETTER OVERALL INITIAL ANALYSIS...ESPECIALLY ON SYSTEM OVER MONTANA AND WYOMING... DOING BETTER ON CLOUD COVER AND MAXES...AND HAVING A SLIGHTLY MORE AMPLIFIED/LESS PROGRESSIVE PATTERN. MAY BLEND RUC IN FOR TONIGHT. FOR TONIGHT/CHRISTMAS DAY...WINDS WILL DIE OFF WITH LOW DEWPOINTS. WILL GO NEAR TO SLIGHTLY BELOW THE MAV WHICH DID BEST ON MINS. LOOKS LIKE THERE IS JUST ENOUGH SNOW COVER IN SOUTHERN GREELEY AND WICHITA TO SLOW DOWN THE TEMPS A LITTLE. WILL SEPARATE THEM OUT MAINLY THROUGH TOMORROW FOR SLIGHTLY COOLER TEMPS. WITH SOME DOWNSLOPE AND SUNNY SKIES PLAN ON GOING SLIGHLTY ABOVE THE MAV AND NEAR TO BELOW THE ETA MOS. FOR WEDNESDAY NIGHT/THURSDAY...STRONGER SHORTWAVE MOVES THROUGH LATE IN THE NIGHT AND EARLY IN THE DAY AS A ETA/GFS DEVELOP SOME SORT OF CUTOFF OVER EASTERN NEBRASKA. THE GFS IS STRONGER THAN THE ETA. GFS HAS DEVELOPED THESE SYSTEMS TOO STRONG RECENTLY. WITH THE WESTERLY WINDS PLAN ON GOING ABOVE THE COOLER MAV/AVN AND CLOSER TO THE ETA. FOR THURSDAY NIGHT/FRIDAY...WEAK PORTION OF JET AXIS MOVES ACROSS DURING THE NIGHT THEN AREA IS IN SUBSIDENCE DURING THE DAY. SYSTEM OVER NEBRASKA MOVES TO THE EAST AS A RESULT OF A SYSTEM MOVING ACROSS THE NORTHERN PLAINS. THEN THE UPPER RIDGE STARTS BUILDING IN DURING THE DAY. ONCE PLAN AGAIN TO WITH THE WARMER GUIDANCE SINCE MAV LOOKS TO COOL BASED ON EXPECTED CONDITIONS. FOR THE 4 TO 7 DAY PERIOD...AS OF 12Z THIS MORNING MODELS WERE NOT AMPLIFIED ENOUGH...ESPECIALLY OVER THE PACIFIC AND WESTERN PORTION OF NORTH AMERICA. THERE WERE ALSO TOO FAST/FAR EAST WITH FEATURES. THE ECMWF WAS DOING A LITTLE BETTER THAN THE 12Z GFS. THERE WERE SOME CHANGES FROM THE PREVIOUS RUN. MODELS WERE A LITTLE SLOWER AND DEEPER WITH TROF MOVING TOWARD THE WEST COAST. THE ECMWF WAS THE SLOWER OF THE MODELS. CONSIDERING THE CURRENT FLOW PATTERN AND JET WOULD THINK THAT THE ECMWF WILL DO BETTER. SATURDAY IS DRY WITH RIDGING AND THE GUIDANCE HAS COME UP DRAMATICALLY. MRF IS NOW AN OPEN WAVE WITH SYSTEM COMING ACROSS ON SUNDAY. WITH DYNAMICS COMING ACROSS WILL KEEP JUST CLOUDS IN FOR SUNDAY. ECMWF HAS SYSTEM DIGGING INTO THE DESERT SOUTHWEST...AND THEN MOVES ACROSS ON MONDAY. THIS LOOKS TOO FAST...AND PROBABLY WILL BE STILL OUT TO THE WEST. WILL KEEP MONDAY AND TUESDAY DRY WITH TROFINESS OUT TO THE WEST AND SOUTHWEST FLOW ALOFT. WILL TEND TO GO NEAR TO ABOVE GUIDANCE WITH GUIDANCE NUMBERS GETTING WARMER AND WESTERLY FLOW ALOFT. .GLD...NONE. BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 100 PM CST TUE DEC 24 2002 MAIN FORECAST CONCERN REMAINS WINTER PRECIPITATION THIS EVENING. SATELLITE AND RADAR LOOPS SHOW A WELL DEVELOPED MID LEVEL CIRCULATION CENTER SOUTH OF KSGF...ALONG THE MISSOURI/ARKANSAS BORDER AT 18Z. A BAND OF LOCALLY HEAVY SNOW IS WRAPPING NORTHWARD AHEAD OF THE SYSTEM...FROM NEAR KSGF TO KSTL AND KMDH. SPOTTER REPORTS FROM PERRY COUNTY MO INDICATED A QUICK INCH OF SNOW BETWEEN 17Z AND 18Z. MODEL QPF...MEAN RH...AND 700 MB OMEGA FIELDS APPEAR TO HAVE A GOOD HANDLE ON THE HEAVY PRECIP SHIELD. THE HEAVIEST PRECIP SHOULD MOVE EAST NORTHEAST...STAYING MAINLY NORTH OF A POPLAR BLUFF TO PADUCAH TO MADISONVILLE LINE. WHERE PRECIP HAS NOT CHANGED TO SNOW...RUC MODEL SOUNDINGS INDICATE IT WILL HAPPEN FAIRLY QUICKLY...BY 21Z AT PAH AND EVV. PRELIMINARY THINKING IS THAT AN ADVISORY WILL BE NEEDED FOR THIS EVENING ALONG AND NORTH OF A PERRYVILLE/KMDH/KOWB LINE. FINAL ADVISORY AREA WILL BE DETERMINED BASED ON RADAR AND SFC OBS AT 21Z. AT ANY RATE...THE 500 MB LOW WILL MOVE EAST OF THE FORECAST AREA AROUND 06Z...ENDING MEASURABLE SNOW CHANCES. IN THE WAKE OF THE SYSTEM...COLD ADVECTION AND AREAS OF NEW SNOW COVER WILL RESULT IN SIGNIFICANTLY COLDER TEMPS. AVN/NGM MOS GUIDANCE IS CLOSE FOR LOWS TONIGHT AND WILL BE FOLLOWED. WIND CHILLS WILL BE AROUND 10 AT KPAH BY MORNING. DESPITE CLEARING SKIES DURING THE DAY ON CHRISTMAS...HIGHS WILL BE ABOUT 10 DEGREES BELOW NORMAL GIVEN 850 TEMPS AROUND MINUS 5 OR COLDER. DRY BUT UNSEASONABLY COLD WEATHER IS EXPECTED CHRISTMAS NIGHT AND THURSDAY AS WEAK 500 MB RIDGING CROSSES THE MISSISSIPPI VALLEY. GFS/EUROPEAN SHOW ONE OR MORE CLIPPER TYPE SYSTEMS IN THE NORTHWEST FLOW THURSDAY NIGHT INTO FRIDAY NIGHT. THE TIMING AND LOCATIONS OF THESE SYSTEMS VARY GREATLY FROM MODEL TO MODEL AND RUN TO RUN. ALTHOUGH LITTLE MOISTURE WILL BE AVAILABLE TO THESE SYSTEMS...SOME LIGHT SNOW OR FLURRIES MAY OCCUR. GFS SHOWS SOME SPOTTY LIGHT QPF LATE IN THE WEEK. UNTIL MORE CONSISTENCY APPEARS IN THE MODELS TIMING OF THESE SHORTWAVES...PLAN TO LEAVE THE FORECAST DRY. A SHARP 500 MB RIDGE WILL BUILD OVER THE MISSISSIPPI VALLEY DURING THE WEEKEND...SETTING THE STAGE FOR A WARMING TREND WITH DRY CONDITIONS. OUTLOOK FOR EARLY NEXT WEEK... THE PAST COUPLE MRF RUNS INDICATE A SURFACE LOW WILL PASS NORTH AND WEST OF THE FA MONDAY...WITH SHOWERS AND MAYBE SOME CONVECTION AHEAD OF THE COLD FRONT. .PAH...WINTER WEATHER ADVISORY FOR THIS EVENING ALONG AND NORTH OF A OWB-MDH-PERRYVILLE LINE. $$ MY ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 1000 AM CST TUE DEC 24 2002 ONGOING FORECAST IS PANNING OUT FAIRLY WELL...HOWEVER UPDATE WILL BE REQUIRED FOR PRECIP TRENDS AND TO REMOVE MORNING WORDING. 12Z RUC 700 MB OMEGA FIELDS AND MEAN RH PROGS SEEM TO HAVE A GOOD HANDLE ON THE AREA OF SNOW OVER MISSOURI AT THIS TIME. THIS SNOW IS ASSOCIATED WITH DEEPENING 500 MB SHORTWAVE OVER EASTERN KANSAS. RUC MEAN RH AND H7 OMEGA FIELDS INDICATE THIS AREA WILL MOVE NORTHEAST...WITH THE BULK OF IT STAYING NORTH OF THE OHIO RIVER THIS AFTERNOON. RUC MODEL SOUNDINGS INDICATE FREEZING RAIN OVER THE FORECAST AREA WILL CHANGE TO SNOW THIS AFTERNOON...IN LINE WITH GOING FORECAST. UPDATE WILL CONTINUE THE ADVISORY WHERE IT IS IN EFFECT...BUT WILL RAISE SNOW AMOUNTS TO 1 TO 3 INCHES FOR MUCH OF SRN ILLINOIS AND PARTS OF SE MISSOURI. THIS IS BASED ON HPC HEAVY SNOW DISCUSSION...AS WELL AS 12Z MODEL QPF GUIDANCE. .PAH...WINTER WEATHER ADVISORY FOR THIS AFTERNOON AND TONIGHT NORTHWEST OF A KPOF-KFWC LINE. WINTER WEATHER ADVISORY FOR TONIGHT FOR SOUTHWEST INDIANA...THE REMAINDER OF MO AND IL AND WEST OF A KOWB-MAYFIELD LINE IN KENTUCKY. MY ...PREVIOUS AFD... MAIN FORECAST CHALLENGE IS PRECIP TYPE/AMOUNT/TIMING WITH THE APPROACH OF THE SOUTHWESTERN U.S. UPPER LOW ANALYSIS OF THE 24/00Z UPPER AIR PLOTS REVEALED THE FOLLOWING. AT 5H A VERY BROAD TROUGH WAS CENTERED JUST WEST OF THE FOUR-CORNERS AREA WITH LOWEST HEIGHTS AROUND THE 546 DAM. BEST HEIGHT FALLS OF 60 TO 70 DAM WERE WELL UPSTREAM OF THE TROUGH ACROSS WESTERN KS INTO THE RED RIVER VALLEY AND ASSOCIATED WITH A SHORTWAVE TROUGH. THIS AREA OF BEST PRESSURE FALLS MATCHED NICELY WITH THE RIGHT ENTRANCE REGION OF A 100-110 KT 25H JET. WELL DEFINED DRY SLOT IN THE WV IMAGERY POKING INTO THIS AREA SUGGESTS A HELPFUL HAND FROM SOME POTENTIAL VORTICITY PUNCHING INTO THAT ARE. IN THE IMMEDIATE AREA OF THE CENTER OF THE FOUR-CORNERS TROUGH...ALL HEIGHT FALLS WERE UNDER 20 DAM. HOWEVER...ALONG THE CA COAST HEIGHT RISES MAXED AROUND 80 TO 90 DAM. 25H JET STRENGTH ALONG THE BACKSIDE OF THE TROUGH WAS RELATIVELY WEAK MAXING OUT AT ONLY 70-80 KTS. GIVEN THIS SET-UP ALONE...I WOULD ANTICIPATE A RATHER SLOW EJECTION OF THIS THIS TROUGH TOWARDS THE FORECAST AREA. CLOSER TO THE SURFACE...A TIGHT BAROCLINIC ZONE WAS POSITIONED ACROSS CENTRAL TX INTO NORTHWEST AR WITH A 85H LOW OVER THE ARKLATEX REGION AND A SURFACE LOW OVER WEST CENTRAL LA AT 24/03Z. ACROSS THE REGION THROUGH 03Z...PRECIPITATION HAS PRIMARILY BEEN IN THE FORM OF RAIN ACROSS MOST OF WESTERN KENTUCKY AND EXTREME SOUTHEAST MISSOURI. A VARIETY OF SNOW AND FREEZING RAIN HAS OCCURRED ELSEWHERE WITH 2 TO 4 INCHES OF SNOW THE AVERAGE ACROSS THE REMAINDER OF SOUTHEAST MISSOURI AND SOUTHERN ILLINOIS GENERALLY SOUTH OF I-64. NORTH OF I-64 IN ILLINOIS 4 TO 7 INCHES HAS BEEN THE AVERAGE. SOUTHWEST INDIANA HAS AN AVERAGE OF 1 TO 3 INCHES. KPAH 88-D AT 05Z WAS SHOWING PRECIPITATION GRADUALLY COMING TO AN END FROM WEST TO EAST WITH THE WESTERN HALF OF SOUTHEAST MISSOURI NOW PRECIP-FREE AND THE PORTION OF SOUTHERN ILLINOIS NORTH OF I-64 PRECIP-FREE. LOOKS LIKE THE GFS/S TREND THE PAST COUPLE OF NIGHTS OF TWO DISTINCT SHOTS OF PRECIP IS COMING TO FRUITION AND AS SUCH WILL FOLLOW CLOSELY WITH ITS LATEST SOLUTION. THE 00Z RUNS OF THE GFS/ETA/NGM/CANADIAN ARE IN VERY GOOD AGREEMENT OF THE TIMING OF THE EJECTION OF THE FOUR-CORNERS TROUGH/LOW...PLACING IT OVER DODGE CITY KS BY 12Z THIS MORNING...CENTRAL ILLINOIS BY 00Z THIS THIS EVENING AND NEAR THE IN/OH STATE LINE 12Z CHRISTMAS MORNING. HOWEVER...DESPITE THIS GOOD AGREEMENT AMONG THESE FOUR MODELS...I AM A LITTLE CONCERN WITH THE SPEED OF THE EJECTION OF THE LOW GIVEN THE AFOREMENTIONED LACK OF ANY SIGNIFICANT KICKER TO DO SO. ITS A BIT HARD TO JUDGE HOW WELL THE MODELS ARE DOING CONCERNING THEIR 06Z FORECAST FOR THE POSITION OF THE LOW AS THIS IS THE ONLY TIME PERIOD WHERE THERE IS QUITE A VARIETY OF SOLUTIONS. EYEBALLING THE WV IMAGERY AT 06Z PLACES THE LOW IN NORTHWEST NM. IS THE LOW GOING TO TRAVEL FROM NORTHWEST NM TO WESTERN KS IN 6 HOURS??? 4 MODELS SAY YES...BUT HAVE MY DOUBTS. AS SUCH...I/LL STILL FOLLOW THE GFS/S TRENDS FOR TODAY...BUT SLOW FEATURES ASSOCIATED WITH THE APPROACH OF THE UPPER LOW A LITTLE BIT. BULK OF THE HEAVIEST PRECIP BY ISSUANCE TIME LOOKS TO BE CONFINED TO THE CENTRAL AND SOUTHEAST PORTIONS OF THE FORECAST AREA. THEN NEXT ROUND OF ORGANIZED PRECIP LOOKS TO RETURN TO THE NORTHWEST PART OF THE AREA AROUND MID-DAY WITH THE MAXIMA FOCUSED NORTH OF THE FORECAST AREA CLOSER TO THE I-70 CORRIDOR. AS THE MAIN UPPER TROUGH APPROACHES THE AREA THE VARIOUS CRITICAL THICKNESSES WILL BE ON THE DECREASE. COMPARING THESE IN COMBINATION WITH VARIOUS FORECAST SOUNDINGS ACROSS PARTS OF THE AREA SETS UP THE FOLLOWING PRECIP SCENARIO. FOR WESTERN SEMO AND SOUTHERN IL NORTH OF I-64 BEGIN AS FREEZING RAIN GIVEN A PROGGED LACK OF A -10C MOIST LAYER WITH SATURATED SUB-FREEZING SUPERCOOLED PROFILE FROM 700 MB TO THE SURFACE. SWITCH TO SNOW AROUND SUNSET AS ICE CRYSTAL FORMATION BECOMES MORE PROBABLE AS THE COLUMN MOISTENS ABOVE 700MB. SNOW LOOKS TO END AROUND SUNRISE CHRISTMAS. AVN QPF NUMBERS FOR THIS AREA ARE SUGGESTING 0.20 TO 0.30 TOTALS FROM MID-DAY ON WITH 0.10 TO 0.20 OF THAT DURING THE NIGHTTIME DURING THE SNOW EVENT. GIVEN THE COOLING IN THE MID LEVELS THAT IS EXPECTED...LESS THAN -10 AT 85H...WOULD ANTICIPATE ANY SNOW TO BECOME SMALLER AND SMALLER ICE CRYSTALS YIELDING A /DRY SNOW/ BY THE TIME IT ENDS. SO A 20 TO 1 SNOW/RAIN RATIO MAY BE BEST TO USE WHICH WOULD BE A ONE INCH AVERAGE OF ADDITIONAL SNOWFALL. WITH PRECIP EXPECTED TO BEGIN AS FREEZING RAIN AND AN ADDITIONAL 1 INCH OF SNOW ON TOP OF SNOW THAT EXISTS THERE NOW...A WINTER WEATHER ADVISORY FOR THIS AFTERNOON AND TONIGHT LOOKS APPROPRIATE FOR THIS AREA. FOR THE REMAINDER OF SOUTHEAST MISSOURI...THE REMAINDER OF SOUTHERN ILLINOIS SOUTHWEST INDIANA AND FAR WESTERN KENTUCKY THE AREA MAY BE HARD PRESSED TO GET MUCH OF ANY ADDITIONAL PRECIPITATION UNTIL THE LATE AFTERNOON. THEN THIS AREA LOOKS TO HAVE TEMPERATURES ABOVE FREEZING AT THIS TIME...SO ANY PRECIP LOOKS TO FALL AS RAIN AND NOT FREEZE. AFTER SUNSET THE LOWER LAYERS LOOK TO MOISTEN...BUT START OUT AS FREEZING RAIN WITH AGAIN A LACK OF A MOIST -10 C LAYER BUT THEN TRANSITION TO SNOW AS THE COLUMN MOISTENS. HOWEVER THE BEST LIFT WILL BE EAST OF THE AREA BY THEN AND ASSOCIATED QPF NUMBERS ARE 0.10 TO 0.20. SO FOR THIS AREA BY MIDNIGHT THE COLUMN HAS MOISTEN...HAS ICE CRYSTALS...BUT WITH SLIGHTLY WARMER SUB-FREEZING TEMPS. SO A RATIO CLOSER TO 10 TO 1 MIGHT BE PRUDENT IN THIS AREA...OR TOTALS UP TO TWO INCHES AFTER AN INITIAL START OF FREEZING RAIN. WILL ISSUE AN ADVISORY FOR THIS AREA AS WELL. THE HOPKINSVILLE REGION OF WESTERN KY MAY BE FINISHED WITH RAIN THE REMAINDER OF TODAY UNTIL CLOSE TO SUNSET ONCE THIS MORNING/S EPISODE ENDS. THEN THIS EVENING LIGHT PRECIP LOOKS TO DEVELOP STARTING AS LIGHT RAIN AND THEN CHANGING TO LIGHT SNOW WITHOUT A PERIOD OF FREEZING RAIN AS A MOIST -10 C LAYER DEVELOPS PRIOR TO SUB-FREEZING TEMPS AT THE SURFACE. WILL HAVE NO ADVISORIES FOR THIS AREA AND ONLY MENTION TRACE AMOUNTS OF SNOW. WITH PLENTY OF CLOUD COVER...AND SNOW COVERING PARTS OF THE AREA...AND NORTHEAST SURFACE WINDS PROVIDING COLD AIR ADVECTION...WOULD ANTICIPATE TEMPS TODAY TO REMAIN STEADY OR SLOWLY FALL. HIGHS TODAY MAY BE IN THE MORNING HOURS. TONIGHT CLOUDS DON/T LOOK TO CLEAR THE ENTIRE AREA SO SNOW COVER DOESN/T LOOK TO PLAY A ROLE IN HELPING AREAS DROP WELL BE LOW GUIDANCE NUMBERS. WITH MAV/FWC IN FAIRLY GOOD AGREEMENT...WILL GO CLOSE TO A BLEND OF THEIR NUMBERS. FOR CHRISTMAS SKIES LOOK TO CLEAR FROM WEST TO EAST. WESTERN AND NORTHERN AREAS SHOULD REALIZE LOWS BELOW GUIDANCE GIVEN THE SNOW PACK. ELSEWHERE WILL GO CLOSE TO MAV/FWC WHICH ARE SIMILAR. WEDNESDAY NIGHT LOOKS TO BE A NIGHT TO PICK UP SOME POINTS ON GUIDANCE. MOSTLY CLEAR SKIES...LIGHT WINDS AND A SNOW PACK SHOULD ALLOW WOULD SUGGEST UNDERCUTTING GUIDANCE BY AT LEAST LEAST A CATEGORY IN THESE AREAS. DENSE FOG MAY BECOME A PROBLEM THAT NIGHT OVER THE SNOW PACK. FOR NOW I/LL ONLY MENTION PATCHY FOG IN THESE AREAS. WILL CONTINUE THE TREND OF COOLER THAN GUIDANCE HIGHS WEST AND NORTH INTO THURSDAY AS WELL. THANKS SDF FOR COORDINATION/COLLABORATION. $$ DFS ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1038 PM EST TUE DEC 24 2002 AT 03Z...A STRONG SURFACE LOW WAS MOVING THRU CENTRAL KY...WITH SYNOPTIC SNOW PUSHING INTO FAR SOUTHERN LOWER MI. A WEAK 1011MB MESOLOW (PROBABLY LAKE-INDUCED) WAS JUST E/SE OF THE SAULT. KAPX RADAR IS SHOWING AN INCREASE IN LIGHT RETURNS (AROUND 0 DBZ) BETWEEN M-32 AND THE STRAITS...WITH UNKNOWN PRECIP REPORTS FROM KPLN/KSLH IN THE LAST COUPLE OF HOURS. KPLN EMPLOYEES REPORT THIS IS CURRENTLY SNOW. EASTERN UPPER HAS BEEN REALLY HARD TO GET A HANDLE ON. NO RADAR RETURNS NOTED THERE...EVEN FROM MONTREAL RIVER ONLY ABOUT 50SM NORTH. LAW ENFORCEMENT IN THE SAULT REPORTS A FEW FLURRIES (AFTER VERY LIGHT FREEZING DRIZZLE EARLIER THIS EVENING). BUT THE MANUAL OBS FROM SAULT ONTARIO (CYAM) ARE A CONCERN...WITH VISIBILITIES 1/2SM OR LESS IN MODERATE TO HEAVY SNOW FOR ABOUT 90 MINUTES (THIS JUST ENDED AT 03Z). IN THE SE...MOST RECENT RUC AND ETA RUNS SHOW POOR AGREEMENT AS TO HOW FAR NW SYNOPTIC PRECIP WILL GET. ETA HAS HAD A SURPISINGLY DECENT HANDLE ON THIS SYSTEM...AND IS DOING BETTER WITH QPF UP TO THIS POINT (SPITTING OUT SNOW AROUND CHICAGO THIS EVENING). AM THUS INCLINED TO FOLLOW THE ETA FAIRLY CLOSELY... KEEPING PRECIP SPOTTY IN THE SE ZONES (RUC WOULD ME TOWARD SOMEHWHAT HIGHER POPS/ACCUMS). FOR THE REST OF NORTHERN LOWER...AM NOT INCLINED TO END PATCHY FREEZING DRIZZLE JUST YET. THOUGH 00Z KAPX SOUNDING SUPPORTED FLURRIES WITH A MOIST LAYER TO -12C...THIS MOIST LAYER IS PROGGED TO BECOME SHALLOWER OVERNIGHT...AND FREEZING DRIZZLE HAS BEEN AN ISSUE UPSTREAM EARLIER THIS EVENING (REFERENCE RECENT DISCUSSION FROM NWS MARQUETTE). THUS WILL CONTINUE WITH FLURRY/FREEZING DRIZZLE MIX... THOUGH WITH THE EMPHASIS ON FROZEN PRECIP. EASTERN UPPER...LACK OF RADAR ECHOES MAKES IT HARD TO KNOW WHAT/S GOING ON NOW...LET ALONE WHAT WILL HAPPEN LATER ON. STILL...I ASSUME THAT CONVERGENCE/FUNNELING ASSOCIATED WITH NW FLOW WHEN THE MESOLOW WAS NORTH OF THE SAULT WAS RESPONSIBLE FOR HEAVIER SHSN. THE LOW APPEARS TO BE EAST OF THE SAULT VIA OBSERVED WINDS. LAKE EFFECT OVER WHITEFISH BAY/SAULT AREAS IS LESS A THREAT IN THIS SCENARIO. WILL CONTINUE WITH SCT SHSN...BUT LITTLE ADDITIONAL ACCUMS. MERRY XMAS TO ALL...AND TO ALL A GOOD NIGHT. .APX...NONE. ZOLTOWSKI mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1032 PM EST TUE DEC 24 2002 AFTER WATCHING RADAR TRENDS AND LOOKING AT LATEST RUC AND MESOETA QPF...WILL HOIST SNOW ADVISORY FOR THREE SE COUNTIES AS THIS CHRISTMAS EVE SNOWSTORM IS EXPECTED TO DROP ABOUT 3 TO 6 INCHES THERE BY THE TIME THINGS WIND DOWN SHORTLY AFTER 12Z WED. NOTED THAT AZO WENT FROM 10 MILE VISBY TO A MILE AND A HALF IN AN HOUR AS MID LEVEL DRY LAYER SEEN ON LAPS SOUNDINGS BECAME SATURATED. WAS WORRIED ABOUT THE WESTERN EXTENT OF THE ACCUMULATING SNOW...BUT COMPOSITE RADAR LOOP BEGINNING TO SUPPORT THE RUC/ETA IDEA OF TAKING THE PRECIP SHIELD OFF TO THE NE OVERNIGHT...WITH THE NW EXTENT OF THE ACCUMULATING SNOW EXPECTED TO BE ALONG A LINE FROM MKG TO AMN. WILL BUMP TOTALS/POPS UP SLIGHTLY ALL ZONES FOR BOTH FIRST AND EARLY SECOND PERIOD. ZONE UPDATE OUT. OSTUNO .GRR...SNOW ADVISORY FOR KALAMAZOO...CALHOUN...AND JACKSON COUNTIES. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1010 PM EST TUE DEC 24 2002 MAIN FCST ISSUE FOR THE OVERNIGHT IS FZDZ. ISSUED FZDZ ADVY EARLIER THIS EVENING FOR BARAGA/MARQUETTE/ALGER AS FZDZ BECAME WIDESPREAD AND SIGNIFICANT ENOUGH TO PUT A THIN GLAZE ON NONTREATED SFCS. KMQT RADAR IMAGERY HAS SHOWN CLASSIC FZDZ SIGNATURE THIS EVENING WITH BROAD AREA OF LOW REFLECTIVITIES WITHIN ABOUT 30MILES OF RADAR. TREND DURING THE LAST COUPLE OF HRS HAS BEEN FOR A STEADY DECREASE IN ECHO INTENSITIES...AND FZDZ HAS BECOME LIGHTER HERE AT THE OFFICE. OUT OVER THE LAKE...STRUCTURE OF RADAR RETURNS LOOKS MORE LIKE SNOW ON LATEST IMAGES...SO THERE MAY BE A TRANSITION UNDERWAY NOW TOWARD MORE SNOW THAN FZDZ. EXAMINATION OF 00Z ETA/RUC TEMP/MOISTURE PROFILES SHOWS ESSENTIALLY NO CHANGE DURING THE OVERNIGHT. SATURATED LAYER REMAINS FROM SFC TO ABOUT 2.5KFT WITH SIGNIFICANT DRYING TAKING OVER AOA 5KFT. WITHIN THE MOIST LAYER...ETA AND RUC FCST SOUNDINGS SHOW TEMP PROFILE -10C OR WARMER...SUPPORTING A CONTINUED POTENTIAL FOR A LACK OF ICE NUCLEATION AND THUS FZDZ THAT HAS BEEN OBSERVED. INTERESTING TO SEE THAT KGRB/KAPX/KINL/CWPL 00Z SOUNDINGS ALL HAVE TEMP OF -11C OR LWR IN THE MOIST LAYER...SUGGESTING SNOW SHOULD BE PTYPE. DIFFICULT TO EXPLAIN WHY THE FZDZ IS OCCURRING UNLESS THERE A POCKET OF WARMER AIR OVER THE AREA POSSIBLY AS A RESULT OF LK MODIFICATION OF AIRMASS. GIVEN THAT ETA/RUC SHOW NO CHANGE IN THE TEMP/MOISTURE PROFILE OVERNIGHT AND WEAK FLOW IS TO BECOME MORE NRLY (WHICH WILL ALLOW UPSLOPE FLOW TO BECOME AN INCREASING FACTOR)...BELIEVE OCCASIONAL FZDZ WILL PERSIST. WILL LEAVE FZDZ ADVY UP FOR BARAGA/MARQUETTE/ALGER THRU THE NIGHT DESPITE WHAT APPEARS A LIKELY TRANSITION TO MORE SNOW THAN FZDZ PER LATEST RADAR TRENDS. HAVE ONLY RECEIVED REPORTS OF SPOTTY FZDZ OVER THE W. DIFFICULT TO SAY WHY FLURRIES HAVE BEEN DOMINANT PTYPE THERE AS MODEL SOUNDINGS BASICALLY IDENTICAL TO THOSE OVER THE NCNTRL. WILL LEAVE FCST GENERALLY UNCHANGED THERE OVERNIGHT. LOW CLOUD DECK HAS KEPT TEMPS FROM FALLING THIS EVENING. DON'T EXPECT TEMPS TO FALL MORE THAN A FEW DEGREES FROM CURRENT READINGS FOR THE REST OF THE NIGHT AS CLOUDS HOLD ON. .MQT...FREEZING DRIZZLE ADVY OVERNIGHT MIZ004>006. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 537 PM EST TUE DEC 24 2002 VSBYS AT SAULT MICH AND SAULT ONTARIO HAVE OCCASIONALLY DROPPED TO 1SM OR LESS IN SHSN IN THE LAST 1-2 HOURS. IT IS DIFFICULT TO GET A HANDLE ON WHAT/S GOING ON...AS KAPX/KMQT/MONTREAL RIVER RADARS ARE ALL CLEAN IN THAT AREA. 21Z SURFACE ANAYLSIS AND RUC PROGNOSIS SHOWS A WEAK 1013MB MESOLOW NEAR MONTREAL RIVER. MOST LIKELY...THIS FEATURE IS ENHANCING LOW LEVEL FLOW AND CONVERGENCE INTO WHITEFISH BAY...WITH SHORELINE EFFECTS FUNNELING A BAND INTO THE SAULT. KMQT RADAR IS SHOWING SOME NW FLOW LAKE EFFECT ELEMENTS IN THE MUNISING AREA...THOUGH MUCH WEAKER THAN WHAT MUST BE AFFECTING THE SAULT NOW. WILL ADD SCT SHSN TO CHIPPEWA COUNTY...WITH LOCAL ACCUMS OF AN INCH. AT THIS TIME...DO NOT THINK CIRCULATION FROM OHIO VALLEY STORM WILL EXTEND FAR ENOUGH NORTH TO DISRUPT THE MESOLOW...AND THUS WILL NOT MENTION ANY TIMING. .APX...NONE. ZOLTOWSKI mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 408 PM EST TUE DEC 24 2002 THE LATEST APX 88D SHOWS A BAND OF LIGHT SNOW SHOWERS/FLURRIES OVER NORTHWEST LOWER/STRAITS REGION...PATCHY FREEZING DRIZZLE OVER EAST UPPER MICHIGAN...AND DRY OVER THE REST OF THE FORECAST AREA. THE LATEST SATELLITE TRENDS SHOW AN AREA OF CLOUDS OVER THE ENTIRE GREAT LAKES...WITH AN AREA OF DEFORMATION CLOUDS MOVING TOWARD SOUTHWEST LOWER MICHIGAN. THE LATEST SURFACE CHART SHOWS A WEAK SURFACE FRONT LOCATED ACROSS THE STRAITS AND UPPER MICHIGAN...WITH AN AREA OF HIGH PRESSURE OVER LOWER MICHIGAN AND THE WESTERN LAKES. MODEL DATA WAS IN GOOD AGREEMENT THIS RUN WITH A STORM SYSTEM MOVING OVER THE SOUTHERN OHIO VALLEY TONIGHT/WEDNESDAY...WITH SURFACE RIDGING MOVING IN THROUGH THURSDAY. THE MAIN FORECAST QUESTIONS WILL BE BASICALLY THE CHANCE AND TYPE OF PRECIPITATION THROUGH THE PERIOD. TONIGHT...THE WEAK RETURNS CURRENTLY OVER THE STRAITS AREA ARE IN RESPONSE TO A WEAK 500MB TROUGH MOVING INTO CENTRAL UPPER MICHIGAN... WITH AN ASSOCIATED VORT LOBE DROPPING INTO NORTHERN LAKE MICHIGAN. RUC MODEL SOUNDINGS SHOW LIMITED MID AND UPPER LEVEL MOISTURE OVER NORTHERN LOWER AND EAST UPPER MICHIGAN...WITH THE SURFACE BASED MOISTURE LAYER EXTENDING INTO TEMPERATURES SLIGHTLY WARMER THAN -10C. THEREFORE SNOWFALL SHOULD BE LIMITED ACROSS THE REGION TONIGHT ...IF NOT BECOMING FREEZING DRIZZLE DUE TO THE LACK OF ICE CRYSTALS WITH TEMPERATURES WARMER THAN -10C. MODEL DATA SHOWS THE UPPER TROUGH TO MOVE SLOWLY EAST/SOUTHEAST INTO THE REGION TONIGHT...WITH 700/500 QVECTORS SHOWING SOME CONVERGENCE OVER THE FORECAST AREA THIS EVENING. LAKE EFFECTS WILL ALSO BE AN INFLUENCE TONIGHT. 850MB TEMPERATURES WILL BE AROUND -10C WITH 1000/850 MB WINDS FROM THE NORTHEAST...WITH 900/700MB MOISTURE AROUND 70 PERCENT. RUC MODEL SOUNDINGS SHOW INVERSION HEIGHTS AROUND 3700 FEET TONIGHT... THEREFORE SNOW ACCUMULATIONS SHOULD BE LIMITED. WITH THE UPPER TROUGH MOVING SOUTHEAST TONIGHT AND LAKE EFFECTS...WILL MENTION FLURRIES OR LIGHT SNOW SHOWERS AND PATCHY FREEZING DRIZZLE TONIGHT. WEDNESDAY...THE SURFACE STORM SYSTEM WILL MOVE OVER SOUTHERN OHIO IN THE MORNING...MOVING ONTO THE EAST COAST DURING THE AFTERNOON. ADDITIONAL DYNAMICS OVER THE REGION WILL BE FROM AN UPPER TROUGH SLIDING SOUTHEAST OVER THE STATE...WITH A VORT LOBE MOVING SOUTHEAST OF SAGINAW BAY BY THE EVENING. AGAIN MOISTURE WILL BE LIMITED OVER EAST UPPER AND NORTHERN LOWER MICHIGAN...AND THE SURFACE BASED MOISTURE LAYER DOES NOT EXTEND INTO TEMPERATURES COLDER THAN -10C. LAKE EFFECTS WILL HAVE A CONTINUED INFLUENCE OVER THE AREA. 850MB TEMPERATURES WILL BE AROUND -10C IN THE MORNING...WARMING TO AROUND -7C DURING THE AFTERNOON. 1000/850MB WINDS WILL BE FROM THE NORTHEAST IN THE MORNING TURNING TOWARD THE NORTH BY THE AFTERNOON. MODEL SOUNDINGS SHOW INVERSION HEIGHTS TO BE AROUND 3500 FEET EARLY...WITH LIMITED MOISTURE AND INVERSION HEIGHTS DROPPING TO UNDER 3000 FEET BY THE EVENING. THEREFORE WILL MENTION A CHANCE OF SNOW SHOWERS OVER NORTHEAST LOWER DUE TO LAKE EFFECTS...AND THE STORM SYSTEM MOVING OVER THE OHIO VALLEY. THURSDAY/THURSDAY NIGHT...SURFACE RIDGING WILL BE BUILDING ACROSS THE WESTERN LAKES THURSDAY MORNING...BEFORE AFFECTING THE ENTIRE REGION BY THURSDAY AFTERNOON. ADDITIONALLY...UPPER LEVEL RIDING WILL MOVE OVER THE STATE THURSDAY...WITH MID LEVEL QVECTORS SHOWING DIVERGENCE LINGERING OVER THE STATE INTO FRIDAY. MOISTURE WILL BE LIMITED WITH 850/700 AND 700/300 MB MOISTURE DRYING TO AROUND 30 PERCENT THURSDAY MORNING...AND LINGERING INTO FRIDAY. THEREFORE WILL MENTION DRY CONDITIONS OVER THE FORECAST AREA WITH SOME SUN. FRIDAY THROUGH TUESDAY...SURFACE RIDING WILL REMAIN OVER THE EASTERN LAKES THROUGH FRIDAY...SUPPLYING SLIGHTLY ABOVE NORMAL TEMPERATURES FOR THIS TIME OF YEAR. THEN A STORM SYSTEM WILL MOVE OVER THE UPPER MIDWEST FRIDAY NIGHT...MOVING OVER THE STATE ON SATURDAY. MODELS ALSO PUSH AN UPPER TROUGH THROUGH QUICKLY BEHIND THE COLD FRONT ON SATURDAY. TEMPERATURE PROFILES WITH 850MB TEMPERATURES AROUND -4C... WOULD SUGGEST AN ALL SNOW EVENT FOR THE REGION. SLIGHTLY WARMER AIR WILL BE MOVING IN SUNDAY IN ADVANCE OF A STORM SYSTEM AGAIN MOVING OVER THE UPPER MIDWEST...WITH THE LOW CENTER RIDING AS FAR NORTH AS NORTHERN MINNESOTA. 850MB TEMPERATURES IN ADVANCE OF THIS SYSTEM WILL WARM TO BETWEEN 1C AND 3C OVER THE NORTHERN LAKES BY MONDAY. THE SYSTEM WILL MOVE EAST OF THE REGION ON TUESDAY. THEREFORE WILL MENTION A CHANCE OF SNOW ON SUNDAY IN ADVANCE OF THE SYSTEM...WITH A MIX OR RAIN/SNOW FOR LOWER MICHIGAN ON MONDAY AS THE SYSTEM NEARS. .APX...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 200 PM EST TUE DEC 24 2002 LATEST 88D IMAGES SHOW A BAND OF SNOW IN WEAK SW FLOW ACROSS LAKE MICHIGAN. THIS IS OCCURING IN WEAK CONVERGANCE FROM NW WINDS IN WISCONSIN AND WEAK EAST WINDS ACROSS MICHIGAN. LOOKING AT THE VISIBLE SATELLITE LOOP ACROSS THE LOWER PENINSULA AN ENHANCED BAND IS MOVING NORTH AND WILL ONLY IMPACT THIS BAND FOR ANOTHER HOUR OR TWO. SO EXPECT A PERIOD OF LIGHT SNOW IN CHARLEVOIX AND EMMET COUNTIES UNDER THE BAND. ELSEWHERE EXPECT FLURRIES. THE ENHANCED AREA WILL BEGIN TO MOVE INTO EASTERN UPPER AROUND 3 PM AND BRING FLURRIES THERE SO ADDED THAT TO CURRENT ZONES AND TO TONIGHT. RUC MODEL SOUNDINGS STILL SHOW TEMPERATURES IN THE CLOUD LAY TO -10 SO NOT A GREAT AMOUNT OF INSTABILITY AND JUST ENOUGH TO KEEP FLURRIES GOING. TEMPERATURES CURRENTLY NEAR 30 AND HANDLED IN THE ZONES. .APX...NONE. HIRSCH mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 936 AM EST TUE DEC 24 2002 LATEST WATER VAPOR LOOP SUGGESTS THAT A WEAK AND SHEARED S/WV IS MOVING OVER WI AT THIS TIME...WITH IR SAT SHOWING HIGH CLDS ASSOCIATED WITH THE WAVE. MQT RADAR NOT PICKING UP ANY PCPN WITH THIS SYSTEM...BUT SPOTTERS DO REPORT SOME ZL- OVER WESTERN MQT/EASTERN ALGER ASSOCIATED WITH A WEAK CVRG AREA. SAW ALREADY HAS A WLY WIND...WITH THE RUC AND ETA SUGGESTING THAT CVRG AREA WILL WEAKEN THIS MORNING. SO WILL JUST ADDRESS THE ZL- IN NOWCASTS AS IT SHOULD DIMINISH BY LATER THIS MORNING. OTHERWISE...MAIN CONCERN FOR UPDATE IS -SHSN POTENTIAL WITH S/WV. STATIONS IN WI AND EVEN INTO THE ARROWHEAD REPORTING VERY LIGHT SNOW/FLURRIES AS THE S/WV MOVES THRU. WITH THE WINDS STAYING W-NW TODAY SEE NO REASON TO TAKE OUT MENTION OF LIGHT SNOW SHOWERS/FLURRIES TODAY. THE 06Z ETA ACTUALLY SUGGESTS THAT A WEAK CVRG BAND WILL SET UP OVER THE EAST LATER TODAY IN RESPONSE TO WLY FLOW OVER THE WEST HALF OF THE CWFA...AND N FLOW OVER THE EASTERN 1/3. DOUBT THIS WILL AMT TO ANYTHING OF MAJOR SIGNIFICANCE WITH LK-AIR DELTA-T VALUES ONLY AROUND 12C...BUT IT MAY BE ENOUGH TO DROP A HALF AN INCH OF SNOW OVER ALGER COUNTY THIS AFTN. OTHERWISE...CLD CVR LOOKS PRETTY GOOD. MOSTLY CLOUDY ALL DAY. ONLY UPDATE WILL BE TO POSSIBLY INCREASE TEMPS A LITTLE...BUT WILL HOLD OFF ON THAT UNTIL LATER TO SEE LATEST TRENDS. .MQT...NONE. MRD mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 909 PM CST TUE DEC 24 2002 RADAR SHOWING SNOW HAS FINALLY EXITED FORECAST AREA. SATELLITE SHOWING MAIN AREA OF ENHANCEMENT PULLING EAST WITH UPPER LOW JUST EAST OF ST LOUIS AREA EXPECTED TO MOVE INTO EASTERN ILLINOIS BY MIDNIGHT. NEXT CONCERN IS WITH STRATUS DECK CURRENTLY IN CENTRAL IOWA AND ALSO SNEAKING DOWN THROUGH EASTERN NEBRASKA. RUC MODEL SEEMS TO HAVE A HANDLE ON THE STRATUS IN IOWA...AND WOULD SUGGEST SOME OF THIS LOWER CLOUD DECK MAKING IT INTO EASTERN PARTS OF FORECAST AREA OVERNIGHT. SOME FLURRIES OCCURRING WITH THIS DECK SEEM TO BE ASSOCIATED WITH A 700 WAVE THAT IS FORECAST TO DROP INTO NORTHEAST MISSOURI OVERNIGHT. WILL KEEP THINGS CLOUDIER OVERNIGHT IN NORTHEAST PART OF FORECAST AREA WITH A CHANCE OF FLURRIES MENTIONED. NEBRASKA BAND IS TOUGHER CALL...WITH MODELS NOT HANDLING WELL. IT IS THINNER WITH SOME HOLES IN IT...SO HAVE DOUBTS THAT IT WILL MAKE IT INTO NORTHWEST CORNER OF FORECAST AREA...ESPECIALLY SINCE WE HAVE NO SNOW COVER TO AID THE MOISTURE. OTHERWISE...IT WILL BE A CHILLY NIGHT WITH TEENS POISED TO MOVE IN SHORTLY. GOING FORECAST LOOKS PRETTY GOOD IN THAT RESPECT SO WILL JUST DO SOME MINOR TWEEKING BASED ON CURRENT CLOUD TRENDS. PC 245 PM... SATELLITE IMAGERY AND UPPER AIR ANALYSIS SHOW SPLIT FLOW PATTERN ACROSS NORTH AMERICA WITH NORTHERN STREAM RIDGING ACROSS WESTERN CANADIAN PROVINCES/NORTHERN PLAINS...AND BROAD SOUTHERN STREAM TROUGH CURRENTLY MOVING THROUGH MID/LOWER MS RIVER VALLEY. SHORTWAVE EMBEDDED IN SOUTHERN STREAM CURRENTLY PROPAGATING ACROSS FORECAST AREA...WITH BAND OF WRAP AROUND SNOW ACROSS SOUTHEASTERN COUNTIES. EXPECT THIS SNOW TO DIMINISH LATE THIS AFTERNOON AS TROUGH AXIS PASSES EAST OF AREA. OTHERWISE AFTERNOON VISIBLE IMAGERY SHOWS CLEARING ACROSS MUCH OF NEBRASKA/NORTHERN KS WORKING INTO FAR NORTHWESTERN MO. AS UPPER TROUGH CONTINUES TO PULL AWAY FROM REGION CLEARING SHOULD SPREAD ACROSS FORECAST AREA OVERNIGHT. OTHERWISE NORTHERN STREAM RIDGE TO SLOWLY PASS ACROSS REGION THROUGH FRIDAY...KEEPING WEATHER QUIET ACROSS AREA. GUIDANCE TEMPS LOOK REASONABLE THROUGH REMAINDER OF WEEK...ALTHOUGH LOWERED TEMPS ALONG SOUTHERN TIER A COUPLE OF CATEGORIES GIVEN SNOWPACK. STRONG ZONAL FLOW CURRENTLY ACROSS EASTERN PACIFIC WILL SPREAD ACROSS WESTERN CONUS LATE IN THE WEEK BEFORE AMPLIFYING THIS WEEKEND. RUN TO RUN INCONSISTENCY FROM EXTENDED MODELS HAS LEAD TO A LOW CONFIDENCE FORECAST FOR EARLY NEXT WEEK...ALTHOUGH GFS/EC MODELS ARE IN AGREEMENT DIGGING SHORTWAVE THROUGH REGION MONDAY. HAVE INCLUDED CHANCE OF RAIN CHANGING OVER SO SNOW MONDAY INTO MONDAY NIGHT ACROSS AREA...ALTHOUGH GIVEN RECENT TREND OF FLOW SPLITTING ALONG PACIFIC COAST WITH ACTIVE SOUTHERN STREAM DEVELOPING ACROSS SOUTHERN STATES...WOULDN'T BE SURPRISED TO SEE BRUNT OF SHORTWAVE ENERGY ONCE AGAIN PASS SOUTH OF MAJORITY OF FORECAST AREA. SEAMAN 115 PM QUICK UPDATE FOR ZONES. DEFORMATION ZONE IN UPPER WAVE HAS GONE THROUGH DRY...THUS HAVE UPDATED SOUTHWESTERN ZONES TO REMOVE ACCUMULATING SNOWS. LOOKS LIKE TOTAL FOR TODAY HAS BEEN FROM 2-4". AS BEST ISENTROPIC LIFT IS AFFECTING SOUTHEASTERN ZONES NOW...HAVE UPPED POPS TO OCNL AND ALSO MENTIONED UP TO 2" POSSIBLE. SNOW HAS COME DOWN IN BURSTS...BUT AS LIFT ENDS QUICKLY THIS AFTERNOON...SNOW SHOULD BE SHORT LIVED. TEMPERATURES LOOKED OK. ONLY OTHER CHANGE WAS TO START CLEARING THE CLOUDS IN THE NORTHWEST CORNER. NEW ZFP ALREADY OUT. LVQ 325 AM... MAIN CONCERN FOR THIS MORNINGS FORECAST CENTERS AROUND HOW FAR NORTH THE SNOW WILL FALL THIS MORNING. THE UPPER LEVEL TROUGH CONTINUES TO HANG BACK OVER THE DESERT SOUTHWEST THIS MORNING...WITH A NUMBER OF SHORT WAVES MOVING NORTHEAST THROUGH THE FLOW DOING THE DIRTY WORK. THE ONLY SNOW REPORTS RECEIVED THUS FAR WERE IN WEST CENTRAL MISSOURI...AND THEY WERE LIMITED TO TRACE AMOUNTS. OUR SECOND SHOT OF SNOW IS STARTING TO FORM IN SOUTHEAST KANSAS AND SOUTHERN MISSOURI AS A SECOND WAVE...BEST SEEN IN THE WATER VAPOR IMAGERY...MOVES NORTHEAST TOWARDS THE LAKES. OKC TUL ICT AND SGF RADARS ARE STARTING TO FILL IN RAPIDLY IN THE 700 MB TROUGH THAT IS DEFINING THIS SECOND WAVE. BANDING ON THE RADAR CAN BE SEEN SLOWLY MOVING NORTH THROUGH SOUTHWEST MISSOURI. TO THE WEST A WEAK 500 MB DEFORMATION ZONE OVER CENTRAL KANSAS HAS BROUGHT SOME FLURRIES TO AREAS SUCH AS MHK AND TOP. MESO ETA...WITH ITS HIGHER RESOLUTION...SEEMS TO HAVE AS GOOD A BEAD AS ANY OF THE MODELS ON THE SMALL SCALE WAVES THAT ARE DOMINATING THIS WEATHER EVENT. A VERY TIGHT GRADIENT WILL CONTINUE TO BE THE MAIN FEATURE ASSOCIATED WITH THIS MORNINGS SNOWFALL. AS THE WAVE MOVES INTO SOUTHERN MISSOURI IT WILL DEVELOP A STRONGER AND MORE WELL DEFINED CIRCULATION. WITH THIS IN MIND...AND EXTRAPOLATING THE MOVEMENT OF THE WAVE FROM SATELLITE PROFILER AND RADAR DATA... INDICATIONS ARE THAT THE BRUNT OF THE SNOW WILL CONTINUE TO STAY TO OUR SOUTH. MESO ETA AGREES WITH THIS IDEA. EXPECT 1 TO 2 INCHES OF ACCUMULATION THIS MORNING IN THE COUNTIES OF LINN KS BATES MO AND HENRY MO. SLIGHTLY FARTHER NORTH AND EAST AN INCH OF ACCUMULATION CAN BE EXPECTED SOUTH OF A LINE FROM WARRENSBURG THROUGH MOBERLY. A LIKELY CHANCE OF SNOW CAN BE EXPECTED TO CONTINUE IN CENTRAL MISSOURI THROUGH THE AFTERNOON HOURS AS THE WAVE PULLS THROUGH SOUTHERN MISSOURI. AS THE DEFORMATION ZONES FILLS IN BEHIND THE WAVE FLURRIES ARE THE BEST THAT CAN BE EXPECTED FOR ALL OTHER LOCATIONS TODAY. WITH THIS SAID I WILL ALLOW THE ADVISORY IN LINN KS BATES MO AND HENRY MO TO EXPIRE. CUTTER .EAX... KS...NONE. MO...NONE. mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 340 PM CST TUE DEC 24 2002 USING STLT TRENDS AND RUC OUTPUT FOR PINNING DOWN EXIT OF STORM ACR CWFA. S SIDE OF ENHANCEMENT PULLING NE WL TAKE HVIST SNW DURING THE EVE ACR STL METRO AREA. WL GO WITH AN ERY EVE ADVSRY FOR S IL COUNTIES AND E CNTRL AND SE COUNTIES OF MO FOR SVRL ADDL INCHES OF SNOW. FOR THE MOST PART...ACCUM TDA IN THE HVIEST SNW AREAS GENLY 4-5 INCHES SO FAR...ALTHO MESO SCALE BANDING MAY HV CERTAINLY PRODUCED GRTR AMTS. ACCUM SNWS OVR MID MO SHUD BE ENDING SHRTLY...ALTHO VSBYS IN THIS AREA HV BEEN SLO TO IMPROVE. CLRG WL SLOLY WORK ACR AREA LT TNGT AND INTO XMAS DAY...WITH CLDS LINGERING OVR E ZNS UNTIL WED NGT. FAIRLY TRANQUIL CONDS SHUD EXIST FROM CHRISTMAS DAY INTO ERY PART OF WKEND...WITH NXT CHC OF PCPN IN THE FORM OF RAIN LT SUN...AND SPCLY MON. .STL...WNTR WX ADVSRY THIS EVE FOR S IL...XTRM E CNTRL AND SE MO... INCLUDING STL METRO AREA. TRUETT mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 940 AM EST TUE DEC 24 2002 RAIN HAS SPRD OVR THE CWA THIS AM. CNVCTV ACTVTY WELL S OF AREA. LTST SFC ANALYSIS SHOWG MAIN LO IN SRN GA WI SCNDRY LO FRMG IN ERN TN. WRM FNT XTNDG FRM SRN LO THRU CSTL SC...TRYG TO FRM CSTL FRNT. LTST RUC NOT DEPICTG SFC PATTERN TOO WELL BUT DOES FRM CSTL FRNT BY EARLY AFTN. IT IS ALSO SHOWG MID LVL DRYG THIS EVE. HWVR UPR LO STILL TO OUR W AND NOT XPCTD TO SWING THRU TIL TMRW AFTN. CRRNT FCST OF RAIN TDY AND TNGT WI CHC THNDR LTR TNGT AS UPR LO SWINGS THRU LUKS GUD. ONLY MINOR CHGS XPCTD TO UPDATE. MARINE: ADVISORIES ARE POSTED FOR ALL WATERS XCPT S OF CAPE LOOKOUT BUT WE'LL NOW RAISE FLAGS FOR THE SOUTHERN STRETCH ALSO SINCE SEAS WILL LIKELY MOUNT TO 6 FEET PLUS TONIGHT AS DEVELOPING LOW PRESSURE SPAWNS ALONG THE SC COAST THIS AFTN AND TRACKS NE THIS EVENING. SECONDARY AND MORE POTENT SFC LOW FORMS WED 12Z OVER THE ALBEMARLE SOUND REGION. THIS WILL BEEF UP THE SW FLOW OVER ERN NC WATERS TO NEAR GALE FORCE AS THE LOW RAPIDLY DEEPENS AND MOVES N ALONG THE DELMARVA COAST. THE BULK OF CONVECTION DURING THIS TIME WILL LIKELY BE CONFINED ALONG THE GULF STREAM WALL AS MSTR IS SWEPT OFFSHORE. WITH JUST A LITTLE MIXING CHRISTMAS DAY IS POISED TO BRING GALES AND HENCE WILL INCLUDE IN WORDING. LAND THAT SLEIGH SANTA! CGG-G/COLBY nc FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 940 AM CST TUE DEC 24 2002 FORECAST CHALLENGE FOR UPDATE CONCERNS CLOUD TRENDS AND TEMPERATURES. REGION CONTINUES IN VICINITY OF 500MB TROUGH AXIS. WEAK VORTICITY MAX TRACKING SLOWLY EAST ACROSS NORTHERN SD FROM WATER VAPOR HOWEVER OTHER THAN VERY LOW AND HIGH LEVELS MOISTURE ABSENT. RED RIVER VALLEY SANDWICHED BETWEEN IFR/LIFR CIGS WTIH BR ACROSS NW MN AND CENTRAL ND. FRESH ETA SLOWLY SHIFTS CLOUD BANDS EAST IN LIGHT WESTERLY FLOW WHILE RUC HOLDS EVERYTHING IN PLACE. THERE DOES APPEAR TO BE A SLIGHT EASTWARD SHIFT. WILL WAIT FOR A FEW MORE IMAGES BEFORE DECIDING ON CLOUD ADJUSTMENTS. HOWEVER WILL NEED MORE CLOUD MENTION OVER WESTERN FA TODAY FOR SURE. WITH FRESH SNOW AND SHORTEST SOLAR PERIOD OF YEAR NOT MUCH TEMPERATURE RECOVERY EXPECTED EVEN WITH SOLAR. WITH LACK OF MIXING OR WARM ADVECTION AND ABOVE WILL NEED TO TRIM TEMPERATURES A NOTCH OR SO OVER MOST AREAS. .FGF...NONE. VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 930 PM EST TUE DEC 24 2002 NO UPDATES EXPECTED AT THIS TIME. LOW PRESSURE SYSTEM ALREADY IN CENTRAL KENTUCKY...VERY CLOSE TO FCST MOVEMENT OF ETA. LATEST RUC MODEL ACTUALLY MOVES LOW INTO NORTHEAST OHIO BY 12Z...WHICH IS FURTHER NORTH THAN THE ETA FCST. CURRENT 3 HOUR HT FALLS BULLSEYE OVER CENTRAL OHIO...WHICH WOULD ALSO INDICATE A MORE NORTHERLY TRACK THAN THE ETA MODEL. ONLY CONCERN AT THIS TIME IS BAND OF LIGHT FREEZING DRIZZLE/RAIN FROM ZZV TO OSU TO HAO...JUDGING FROM THE RUC THICKNESSES...FREEZING AND MIXED PRECIP SHOULDN'T PROGRESS MUCH FURTHER NORTH THAN CENTRAL OHIO...SO WON'T UPDATE CURRENT FORECAST. .CLE... OH...WINTER STORM WARNING TONIGHT AND CHRISTMAS FOR ZONES OHZ003...OHZ006>014...OHZ017>023...OHZ027>033...OHZ036>038...OHZ047.. .OHZ089. PA...WINTER STORM WATCH FOR TONIGHT AND CHRISTMAS FOR ZONES PAZ001>003. DJB oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 340 PM EST TUE DEC 24 2002 ...WINTER STORM WARNING MOST OF AREA ADDED ADVISORY TO SOUTHEAST COUNTIES ADDED... SNOW BANDS HAVE BEEN MOVING ACROSS THE REGION SINCE ABOUT 4 PM THIS AFTERNOON. THE NOSE OF AN APPROACHING DRY SLOT OVER WEST VIRGINIA KEEPS ENHANCING BANDS IN MARYLAND AND SOUTHERN PENNSYLVANIA. RUC AND ETA DIAGNOSTICS SHOW SOME INSTABILITY AND FRONTOGENESIS FAVORING BAND FORMATION OVER THE SOUTHERN TIER COUNTIES...FROM BEDFORD EAST. SNOW BANDS SHOULD CONTINUE THROUGH ABOUT MIDNIGHT OVER MOST OF THE SOUTHERN TIER AND CENTRAL COUNTIES. THE RADAR IS BEING FORCED TO STAY IN CLEAR AIR MODE TO SEE THE BANDS. SNOWFALL UNDER THESE BANDS IS GENERALLY IN THE 0.5 TO 1 INCH PER HOUR RATE. SOME HIGHER RATES ARE ALONG THE RIDGE TOPS. WILL PUT AN WINTER WEATHER ADVISORY FOR SOUTHEAST AND KEEP WATCH GOING...WILL WAIT TIL 21Z SREF AND 00Z GFS/ETA FOR POSSIBLE WARNING. THE PROBLEM IN THE SOUTHEAST AFTER 4 AM IS HOW MUCH WARM AIR GETS AND AND HOW LONG A PERIOD OF SLEET OR RAIN/SNOW MIX LIMITS SNOWFALL. WILL LIKELY MOVE HEAVY SNOW TO EAST OF PREVIOUS FORECAST AS ANOMALOUS LOW LEVEL JET IS FARTHER EAST. ADDITIONALLY...WILL BIAS AREA ON SREF WITH HIGH PROBABILITY OF MORE THAN ONE INCH OF STORM TOTAL QPF FROM NEAR STATE COLLEGE AND ALTOONA EAST-NORTHEASTWARD TOWARD SCRANTON. THE POSITION OF THE COLD CONVEYOR SNOW CHRISTMAS DAY HAS THE POTENTIAL FROM SOME OVER 12 INCH SNOW AMOUNTS...MOST OF IT TO THE EAST AND NORTHEAST. ALSO...CONVECTION MAY HAVE PRODUCED A TROUGH ALONG THE NC COAST EAST OF FORECASTS AND SEVERAL HOURS FASTER. A SURFACE LOW IS CLEARLY OFF THE COAST OF NC SE OF WILLMINGTON. .CTP...WINTER WEATHER ADVISORY AND WINTER STORM WATCH FOR PAZ036-056-057-059-063>066...ALL OTHER AREAS WINTER STORM WARNING. $$ GRUMM/DIRIENZO pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 645 PM EST TUE DEC 24 2002 KGSP RADAR INDICATING NO ACTIVITY AT THIS TIME...THOUGH SURFACE OBS INDICATE SOME VERY LIGHT RAIN SCATTERED ABOUT. SURFACE FEATURES TO SW GENERATING ONLY ISOLATED ACTIVITY. SHOWERS IN CENTRAL TN ASSOCIATED WITH VORT...AND WILL AFFECT MOUNTAINS IN SEVERAL HOURS. WILL TRIM EVENING POPS TO CHANCE. MIN TEMP FORECAST LOOKS GOOD...BUT ADJUSTED EVENING TEMP/DEW POINT DOWN A COUPLE OF DEGREES. MESOETA WINDS DELAY FROPA A BIT. UPDATED OVERNIGHT TRENDS OF TEMPERATRU...DEW POINT...RH AND WIND CHILL. HAVE NOT YET DECIDED ON WHETHER TO REMOVE POPS E OF MOUNTAINS OVERNIGHT. CASE FOR POPS WEAK...ESPECIALLY AS LOW LEVEL FLOW STARTS TO TURN TO W COMPONENT. WILL EVALUATE/COLLABORATE FURTHER. AS FOR WIND/SNOW IN MOUNTAINS...850/925 MB FLOW JUST STARTS TO OBTAIN AN ORTHOGONAL COMPONENT TOWARD END OF PERIOD...AND RUC 850 MB VELOCITIES AROUND 30 KTS...SO ANY ADVISORY CAN WAIT UNTIL SECOND PERIOD. QUESTION IS WHETHER WIND WATCH NEEDED NC MOUNTAINS...AS SUGGESTED BY ETA BUFKIT MOMENTUM TRANSFER AND SHALLOW MIXED LAYER. WILL EVALUATE/COLLABORATE FURTHER. FCSTID = 7 GSP 38 47 26 47 / 40 10 0 0 AND 39 49 27 48 / 40 10 0 0 CLT 39 48 24 49 / 30 10 0 0 HKY 35 42 24 44 / 40 10 0 0 AVL 34 39 23 41 / 50 20 0 0 .GSP... GA...NONE. NC...NONE. SC...NONE. O7 sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 915 AM EST TUE DEC 24 2002 ONLY MINOR CHANGES TO FORECAST AT 930. SNOW IS REPORTED BY SEVERAL STATIONS IN NC MOUNTAINS AND PIEDMONT. HOWEVER TEMPERATURES ARE IN THE UPPER 30S SO NO ACCUMULATION EXPECTED TODAY. NO CHANGES IN FLASH FLOOD WATCH. PRECIP ACCUMULATIONS ARE APPROACHING TWO INCHES. ONE NOTE...RADAR IS OVERESTIMATING PRECIP BY AT LEAST A FACTOR OF TWO. RUC HAS HEAVIEST PRECIP OUT OF THE AREA BY 18Z WITH ANOTHER MINOR SHOT COMING IN LATER TONIGHT. .GSP... GA...FLOOD WATCH THROUGH TONIGHT GAZ010-017>018-026-028. NC...FLOOD WATCH THROUGH TONIGHT NCZ051-058>059-062>067. SC...FLOOD WATCH THROUGH TONIGHT SCZ001>007-010. DICARLO sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CHARLESTON SC 746 AM EST TUE DEC 24 2002 UPDATE: ELEVATED CONVECTION QUITE EXTENSIVE AND NOT FAR FROM OUR WRN GEORGIA COUNTIES. UPDATED ZONE FORECAST TO TAKE OUT AFTERNOON THUNDER WORDING. ALSO WARM FRONT IS FURTHER INLAND THAN PREVIOUSLY ANTICIPATED AT 12Z. RAISED TEMPS AND ADJUSTED WINDS TODAY. ----------------------- PREVIOUS DISCUSSION ---------------------- ZFP: ANOTHER QUICK-HITTING AND COMPLEX STORM SYSTEM FOR THE SE STATES ON TAP TODAY. EACH OF THE MODELS OFFER UP A DIFFERENT SURFACE EVOLUTION THROUGH TONIGHT AND OVERALL CONFIDENCE IS LOW WHICH IS MORE OF A CONCERN FOR THE COASTAL WATERS FCST. WHAT IS OF BETTER CONFIDENCE IS CATEGORICAL POPS TODAY WITH NICE UPPER LEVEL DYNAMICS AND GOOD LOW LEVEL CONVERGENCE. THREAT OF SIGNIFICANT TSTMS LOOKS MINIMAL...BUT IT DEPENDS ON WHERE THE COASTAL FRONT IS THIS AFTN. WILL CONTINUE THE MENTION OF POSSIBLE TSTMS ALL ZONES TODAY. TEMPS COULD BE A REAL NIGHTMARE...WILL TREND 50-55 INLAND SOUTH CAROLINA ...55-60 COAST AND 60-65 IN SE GEORGIA. WILL MAKE A LAST MINUTE CALL ON WHETHER TO MENTION RNFL HEAVY AT TIMES TDA. RAINS SHOULD BE ENDING TONIGHT WITH DRY AIR WRAP QUICKLY RUSHING INTO THE NEGATIVELY TILTING LOW PRES TO OUR N. WED IS LOOKING MORE AND MORE LIKE A WIND ADVISORY DAY...WILL INTRO WINDY INTO THE ZONES FOR NOW. SKIES WILL BECOME MOSTLY SUNNY CHRISTMAS AFTN WITH STRONG MIXING EXPECTED. NO SIGNIFICANT WEATHER ANTICIPATED IN THE DAY 3-7 PERIODS. MAINLY BELOW CLIMO TEMPS UNTIL SOMETIME THIS WEEKEND. CWF: COORD WITH JAX/ILM THIS MORNING. GFS SOLN APPEARS TOO AGGRESSIVE WITH COASTAL LOW PRES FORMATION AROUND MIDDAY. THE LATEST RUC IS CLOSER TO THE 00Z ETA AND IS PREFERRED. PLAN TO BACK DOWN WIND AND SEAS A BIT FROM OUR PREVIOUS FCST TODAY BUT WILL RAISE SCA FOR ALL WATERS EXCEPT THE CHS HARBOR. BY MID AFTN WINDS COULD BE GUSTY NE OR LIGHT SW ALG NERN CHARLESTON COUNTY...CERTAINLY A DIFFICULT FCST. CHRISTMAS DAY WILL FEATURE STRONG WLY FLOW AND GALES WELL OFFSHORE AND STRONG SCA CONDITIONS ACROSS OUR WATERS. NOT MUCH CHANGE TO LATTER PERIODS. CHS 58 49 57 30 / 100 70 10 0 SAV 63 46 55 28 / 100 50 0 0 CHL 59 53 58 35 / 100 70 10 0 NBC 60 47 55 31 / 100 70 10 0 RBW 53 46 55 29 / 100 70 10 0 MHP 60 46 54 29 / 100 40 0 0 .CHS... GA...SMALL CRAFT ADVISORY AMZ354-374. SC...SMALL CRAFT ADVISORY AMZ350-352. 24 sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 640 AM EST TUE DEC 24 2002 BAND OF SHOWERS AND THUNDERSTORMS ACROSS CENTRAL AND NORTH GEORGIA MOVING EAST-NORTHEAST TOWARD THE SAV RIVER. SATELLITE INDICATING CLOUD TOPS COOLING. RUC AND 06Z META INDICATES POTENTIAL FOR ELEVATED CONVECTION INCREASING ACROSS THE CENTRAL AND SOUTHERN MIDLANDS. SHOWWALTER INDEX AROUND -1 IN THE CSRA. SFC-3KM SHEAR STRONG. WILL UPDATE FORECAST AND ADD ISOALTED THUNDERSTORMS TO ALL CWA EXCEPT NORTH MIDLANDS. FCSTID = 19 CAE 49 46 52 30 / 100 70 20 10 AGS 53 48 53 30 / 100 60 10 10 SSC 49 46 51 30 / 100 70 20 10 OGB 53 48 54 31 / 100 60 20 10 .CAE... GA...NONE. SC...NONE. AWP sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 343 PM CST TUE DEC 24 2002 ANYTHING OF MAJOR SIGNIFICANCE APPEARS TO BE MISSING FROM MOST OF THIS FORECAST...ONLY PERHAPS IN THE EXTENDED. WK SFC RIDGE OVR ERN PART OF DKTS AND NEBRASKA...BUT OVERALL WK SFC GRADIENT. WIDSPREAD BAND OF LOW CLOUDS BACKED UP AGAINST RIDGE AXIS IN WKLY CONVERGENT LOW LEVEL FLOW. FOG PRETTY MUCH BY THE WAYSIDE NOW... AND ONLY A FEW FLURRIES REMAIN WITH LOW DBZ RETURNS AT KABR WANING. PROBLEM TONIGHT WITH LOWS IS THE CLOUDS...WHICH WILL BE PARAMOUNT TO TEMPERATURE AND TRENDS. EROSION OCCURRING FROM BOTH SIDES...MOST SO ON W. LACK OF PROPAGATION TO E RESULT OF HEATING...AND MORE NLY LOW LVL TRAJECTORY. MDLS DID HORRID JOB INITIALIZING AND NOT A GREAT DEAL OF HELP...COMPARE LACK OF MSTR AND MUCH WKR CAPPING IN KABR SOUNDING VS RUC/ETA INITIALIZATION. CLOUDS SHOULD SLOW DISSIPATION THIS EVENING WITH LESS MSTR FALLOUT FM FLURRIES...AND LOSS OF MIXING. MAY EVEN SEE SOME DEGREE OF REFORMING BLO STRONG INVERSION OVERNIGHT. HOWEVER...CONVERGENCE AXIS BECOMING LESS DEFINED WITH TIME OVERNIGHT...SO LOOK FOR WHATEVER IS LEFT TO UNDERGO RAPID DISSIPATION ON CHRISTMAS. OTHER CLDS ROTATING INTO ERN CWA WITH BACK EDGE OF SWRD SINKING SHEAR AXIS...AND WL BRUSH THRU WITH A FEW FLURRIES BEFORE DISSIPATING LTR TONIGHT AS WELL. LITTLE ELSE OF IMPORTANCE TO OCCUR THROUGH FRIDAY NIGHT WITH TMPS MAIN CONCERN. ELEVATION IN WK FLOW WL BE MORE OF AN EFFECT ON LOWS. WARMER AIR INITIALLY COMING IN FM NW ALFT. FAIRLY DECENT CDFNT FORCED BY SHARP TROUGH DIGGING INTO MN ON MONDAY. DYNAMICS/MSTR TOO SPARSE FOR PCPN MENTION...BUT MAY GET JUST A FEW SC ACRS FAR NE AT BEST. DESPITE RETURN OF COOLER AIR FRIDAY...WL BE MUCH BETTER MIXED DAY AND WL MENTION BREEZY/WINDY...WITH TMPS WARMEST IN SHORT TERM. IN THE EXTENDED RANGE...VOLATILITY OF MDLS CONTINUE WITH STRENGTH OF PAC FLOW. THIS IS NOT ANY BETTER SHOWN BY 3 CONSECTIVE RUNS OF GFS STARTING 18Z YESTERDAY...WHICH WENT FROM COLD AND DRY SUNDAY NIGHT...TO A SIGNIFICANT WINTER STORM FOR ERN SD...TO EXTREMELY MILD AHEAD OF A FRONT. ENSEMBLES NOT A LOT OF HELP AND DEPICT UNCERTAINTY AS WELL...WITH SIG STD DEVIATIONS IN EPAC AND GRTLKS. TREND HAS BEEN FOR MOST MDLS TO GO SLOWER WITH PROGRESSION DUE TO DIGGING ENERGY W...AND MORE DEVELOPMENT DOWNSTREAM WITH FRIDAY DIGGING TROUGH. THIS WL RETARD WARMUP A BIT ON SAT IN THE EAST WITH SFC RIDGE OVER THE AREA EARLY IN THE DAY...AND S TO SE COMP OF LOW LVL FLOW LATER ON WITH WAA ALFT. GRADIENT STRENGTHENS SAT NIGHT AND ELEVATION LOWS SEEM IN ORDER. SUNDAY LOOKS TO BE MILDEST DAY AHEAD OF FRONTAL ZONE IN WRN PLAINS LTR AFTN. WL KEEP TMPS ABOUT 5-10 DEGREES SHY OF RECORDS...AND NERVOUS WITH PROBABILITY OF SW FLOW ALFT CI. WL ADD IN THREAT FOR SNOW LTR SUNDAY NIGHT AND MONDAY SWEEPING THRU CWA WITH FAIR DYNAMICS EVEN WITH STGR NRN STREAM...BUT UNLESS THINGS CHANGE AGAIN CONSIDERABLY...SHOULD NOT BE A BIG DEAL. WL TREND MUCH COOLER WITH FAIR NUMBER OF ENSEMBLE MEMBERS MORE AMPLIFIED TO E EARLY IN WK...BUT STILL NORMAL OR ABR FOR MON/TUE. .FSD...NONE CHAPMAN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1015 AM CST TUE DEC 24 2002 CURRENTLY HAVE SWATH OF LOW CLOUDS ACROSS CENTRAL AND NE SD...WITH SOME AREAS SEEING FOG AND FLURRIES. THESE CONDITIONS ARE SIMILAR TO WHAT OCCURRED ACROSS KMBG AREA AND IN ND YESTERDAY ASSOCIATED WITH AN AREA OF VORTICITY...NOW LOCATED OVER SD. LATEST RUC AND MESO-ETA SHOWING VORT MAX NEARLY STATIONARY OVER CWA THRU 00Z. 12Z KABR SOUNDING SHOWING AMOUNT OF MOISTURE DROPPING OFF SHARPLY ABOVE 925MB...AND ATMOSPHERE SATURATED BELOW THAT POINT. WITH THE VORT MAX REMAINING OVER THE AREA AND THE LOW LVL MOISTURE AVAILABLE...HAVE UPDATED MOST OF CWA TO MOSTLY CLOUDY SKIES FOR TODAY. WILL ALSO KEEP PATCHY FOG WORDING AS MOST SITES WEST OF THE HILLS REPORTING FOG WITH VISIBILITIES BETWEEN 1/2SM AND 3SM. ALSO CANNOT RULE OUT THE POSSIBILITY OF OCCASIONAL FLURRIES BEING SQUEEZED OUT OF THIS THIN LAYER OF LOW CLOUDS ACROSS THE AREA. WITH THE CLOUD COVER HAVE BUMPED MAX TEMPS DOWN A BIT ALSO. .ABR...NONE ALBRECHT sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 940 AM CST TUE DEC 24 2002 UPDATE PLANNED THIS MORNING. 15Z RUC DEPICTING H5 TROUGH EXTENDING FROM ARROWHEAD OF MN THROUGH NORTHERN IA. IR SATELLITE SHOWING HIGH CLOUDS ASSOCIATED WITH THIS FEATURE AND UPPER LOW ROTATING EAST THROUGH EASTERN KS...APPARENTLY SERVING TO PROVIDE ICE CRYSTALS TO PRE-EXISTING LOW/MID CLOUDS FOR SOME FLURRY ACTIVITY ACROSS SOME OF MY NORTHERN ZONES. THIS WILL EVENTUALLY OVERSPREAD SOUTHERN ZONES BY THIS AFTERNOON. WILL UPDATE TO ADD FLURRY MENTION. .LSE...NONE. $$ DAS wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 130 AM EST WED DEC 25 2002 SUBTROPICAL JET MAKING PRONOUNCED APPEARANCE ACROSS SRN CONUS AS MJR SFC LOW DEVELOPS ALONG ERN NOAM COAST. 700MB WAVE READILY APPARENT ON SAT/RADAR PIX ATTM OVER IN, WITH A SWATH OF -SN/SN ASSOC WITH NEWD MVG MID-LEVEL DEFORMATION BAND. AS SFC LOW MOVES NEWD, SFC WINDS OVER FA TURN MORE NWLY WITH FALLING TEMPS. KY-DOT PAVEMENT DATA SHOWING A DECLINING TREND FROM W-E ATTM, SO THERE COULD BE SOME REFREEZING/FZDZ PROBLEMS TWDS MORNING ACROSS LMK FA. WITHIN CYCLONIC FLOW REGIME SOME WEAK LIFT FCST BY ETA CENTERED ON 800-900MB LAYER, GRADUALLY DISSIPATING FROM W-E TWDS AFT. 3Z RUC FCSTS 850MB TEMPS FALLING TO NEAR -11C BY 12Z, BUT DEPTH OF SATURATION WILL MODULATE FINAL PTYPE DURING 1ST PD. SDF ACARS RAOBS ~5Z SHOW DEEP SATURATION, CONSISTENT WITH ETA FCST SOUNDINGS, THEREFORE BELIEVE -SN/SHSN POTL SHOULD CONTINUE BEFORE COLUMN ABV 10KFT DRIES OUT FROM W-E TODAY. WOULD BE MIXED WITH DZ/-FZDZ BTWN SHSN ELEMENTS WHERE ATMS BRIEFLY DRIES OUT ALOFT. EXP PTYPE CHARTS FROM 0Z LMK-MM5 SHOW THIS TREND AS WELL, WITH PBL SNOW CRYSTAL MIXRS EXHIBITING A "SPOTTY" NATURE AND MVG EWD WITH TIME. BEST CHCS OF ACCUMS WOULD BE OVER NRN 1/2 OF FA, ESP OVER SRN IND CLOSER TO BEST DEEP LAYER LIFTING PROCESSES. THINKING UP TO 1" IN GENERAL, THOUGH WOULDN'T BE SURPRISED TO SEE LOCAL 1.5" AMTS IN BETTER SHSN. AFTERWARDS WITHIN SHALLOW CLOUD ENVIRON SOME SCT -FZDZ COULD PERSIST WITH WEAK PBL LIFT HINTED AT THRU EVE. NEXT ITEM OF SOME INTEREST IS WEAK 500MB WAVE FCST TO MV OVER FA ON FRI. MOISTURE IS HIGHLY QUESTIONABLE WITH THIS SYSTEM WITH SFC HIGH CENTERED BTWN US AND GULF OF MEX, BUT GFS FCSTS PW PLUME ~0.3" AHEAD OF THIS FEATURE AND HAS 20-30% SN POPS ACROSS FA FRI. WILL PROBABLY JUST GO M/CLOUDY GIVEN VERY WEAK LIFT FCST AT 700MB, SUGGESTING IF ANYTHING OCCURS IT WOULD BE JUST --SN OR --RA. WARMING TREND OVER THE UPCOMING WEEKEND TO PERHAPS ABV NORMAL TEMPS AS 500MB RIDGE BUILDS OVER CEN/ERN CONUS. .SDF...NONE. XXV ky SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 445 AM EST WED DEC 25 2002 00Z RAOBS/WATER VAPOR LOOP SHOW UPPER LOW OVER THE OHIO VALLEY...WITH BROAD RIDGE BACK ACROSS THE HIGH PLAINS. SURFACE LOW NEAR THE OHIO/WEST VIRGINIA BORDER...WITH COASTAL LOW DEVELOPING JUST OFF THE VIRGINIA COAST. REGIONAL RADARS/SATELLITE SHOW DECENT BANDS NORTHWEST OF THE LOW...FROM INDIANA AND OHIO NORTH ACROSS LOWER MICHIGAN. FORECAST NEARLY A SHORT-TERM UPDATE...AND FORECAST PROBLEMS MAINLY CONFINED TO FIRST 6-10 HOURS OR SO. FIRST PUSH OF SNOW ASSOCIATED WITH DECENT ISENTROPIC LIFT AFFECTED MAINLY THE SOUTHERN CWA /I-94 SOUTHWARD/. DRY MID LEVELS APPARENT ON 00Z DTX SOUNDING LIMITED THE INITIAL NORTHWARD EXTENT OF THE SNOW. CONSEQUENTLY SNOWFALL REPORTS RANGE FROM 3-4 INCHES IN ARB/DTW TO HALF AN INCH AT DTX. COMPLICATING FACTOR ARE MESOSCALE BANDS NORTHWEST OF THE SURFACE LOW...ORIENTED SOUTHWEST/NORTHEAST ACROSS LOWER MICHIGAN. STRONG 700MB/500MB FRONTOGENETICAL CIRCULATION DEPICTED BY 00Z/06 ETA/06Z RUC...WITH RESULTANT UPWARD MOTION ACROSS THE CWA. DIFFICULT TO LINE UP BAND ORIENTATION WITH MODEL FEATURES THROUGH...WITH ONLY A CLOSE APPROXIMATION WITH 500MB FGEN...ALTHOUGH WITH HEIGHT THE MODEL CIRCULATION IS DISPLACED NORTHWARD. BUT THIS LOOKS TO BE THE CLOSEST PROXY...AND SUPPORTS RECENT RADAR TRENDS ACROSS THE REGION. SHORT-TERM MODELS RUNS INDICATE THIS FORCING DROPPING EAST-SOUTHEAST ACROSS THE CWA EARLY THIS MORNING...ALTHOUGH WEAKENING AS IT GOES AS MAIN SYNOPTIC ENERGY TRANSLATES TO THE RAPIDLY DEVELOPING EAST COAST SYSTEM. GENERAL WIDESPREAD SNOWFALL RATES AROUND A HALF INCH PER HOUR...WITH CLOSER TO INCH PER HOUR IN THE MAIN BANDS. IF THIS PERSISTS THROUGH 9-10AM AND MODELS WOULD INDICATE...COULD COULD SEE AN ADDITIONAL 2-4 INCHES ACROSS THE CENTRAL AND SOUTHERN CWA. MORE LIKE 1-3 INCHES ACROSS THE NORTHWEST CWA AS SNOW WILL DIMINISH EARLIER. WITH AROUND AN INCH ALREADY ON THE GROUND...AN ADDITIONAL 2-4 KICKS UP INTO ADVISORY LEVELS. CONSEQUENTLY WILL EXPAND THE CURRENT WINTER WEATHER ADVISORY NORTHWARD FROM WASHTENAW-WAYNE SOUTHWARD TO SHIAWASSEE-SANILAC SOUTHWARD. SOUTHERN CWA IS GOING PROVIDE ADDITIONAL PROBLEMS THROUGH. WITH AROUND 3 INCHES WITH FIRST PUSH OF SNOW...THEY WILL BE APPROACHING WARNING CRITERIA OF 6 INCHES. IWX/CLE RADARS SHOW SOMEWHAT OF A DRY SLOT JUST SOUTH OF MICHIGAN...IN ADDITIONAL WITH REFLECTIVITIES MORE OF A SCATTERED CONVECTIVE NATURE. 06Z RUC40 HAS SOME SEMBLANCE OF THIS...WITH 500MB UVV WEAKENING/BECOME WEAKLY DOWNWARD BEGINNING AROUND 08Z/09Z. HOWEVER RUC ONLY BRUSHES THE FAR SOUTHERN CWA WITH THIS FEATURE...KEEP IT MOVING EASTWARD THROUGH NORTHERN OHIO/LAKE ERIE...GENERALLY AHEAD OF THE 700MB VORT CIRCULATION THATS IS APPARENT ON SATELLITE. WITH THE SOUTHERN FOUR COUNTIES STILL LOOKING TO PICK UP ADDITIONAL ACCUMULATIONS...WILL UPGRADE THEM TO A WINTER STORM WARNING FOR SNOW. DRY AIR QUICKLY MOVES IN FROM THE NORTHWEST AS THE SYSTEM PULLS EASTWARD. LIFT WEAKENS AND ENDS...WITH SNOW FINALLY DIMINISHING THIS MORNING NORTHWEST/EARLY AFTERNOON IN THE EAST. THERMAL PARAMETERS ARE MARGINAL FOR LAKE ENHANCEMENT...AND MINIMAL FOR A TRANSITION TO PURE LAKE EFFECT. INVERSION HEIGHTS CRASH DOWN BELOW 3-4KFT AS WELL...PREVENTING MUCH IF ANY PRECIPITATION. IF WE DID MANAGE ENOUGH LIFT TO PRECIPITATE...PRECIP TYPE WOULD BECOME AN ISSUE ACROSS THE NORTHERN CWA MID LEVEL DRYING DROPS THE TOP OF THE MOIST COLUMN DOWN NEAR -8C...MAKING ICE NUCLEATION DIFFICULT. WITH LESS THAN IMPRESSIVE FORCING WILL JUST PRECIP TO AN END RATHER THAN CARRYING OVER AS DRIZZLE/FREEZING DRIZZLE. SKIES WILL EVENTUALLY CLEAR OUT...LEAVING A PARTLY SUNNY DAY FOR THURSDAY. THANKS FOR GOOD COORDINATION WITH GRR. .DTX...WINTER STORM WARNING FOR SNOW...THIS MORNING... MIZ075-076-082-083 WINTER WEATHER ADVISORY FOR SNOW...THIS MORNING... MIZ055-060>063-068>070 BRAVENDER mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 400 AM EST WED DEC 25 2002 MAIN FCST CONCERNS ARE LINGERING -SN AND -FZDZ THIS MORNING ALONG WITH PCPN TRENDS FOR FRI-SUN. WV IMAGERY AND RUC ANALYSIS INDICATED WRN LAKES IN BTWN NRN STREAM AND POTENT SRN STREAM H5 LO OVER THE OHIO VALLEY. NRN STREAM SHRTWV WAS SWEEPING THROUGH NE ONTARIO LEAVING QVECTOR DIV AND SUBSIDENCE DOMINATING UPR MI UNDERNEATH LEFT ENTRANCE OF H3 JET INTO THE NE CONUS AND 700-500 FRONTOLYTIC FORCING. AT THE SFC...RDG EXTENDED FROM N OF LK SUPERIOR TOWARD THE NRN PLAINS ATOP THE SFC LO OVER THE OHIO VALLEY. WEAK LAKE INDUCED TROF HAD DEVELOPED OVER ERN LK SUPERIOR WITH CONVERGENT NRLY FLOW. AREAS OF -FZDZ HAD PERSISTED OVER NORTH CNTRL UPR MI ALONG WITH SOME --SN. GOES SNDGS INDICATED LOW LVL TEMP/MOISTURE TO NEAR -9C (ABOUT 1C WARMER THAN ETA FCST SNDG) AND INVERSION NEAR 900 MB WHICH WOULD BE MARGINAL/UNFAVORABLE FOR ICE NUCLEATION. KMQT VAD WND PRFL INDICATED RETURNS ONLY TO 3K FT. EVEN LIMITED BUOYANCY OVER THE LAKE WITH LK-(900-850) DELTA/T TO NEAR 13C WAS ENOUGH TO ALLOW MOISTURE TO TAP SLIGHTLY COLDER AIR AND GENERATE MORE SNOWFLAKES AS RADAR PATCHY RETUNRS AOA 16 DBZ OVER THE LAKE WHILE BROADER AREA OF 4-8 DBZ RETURNS PERSISTED INLAND. ACYC 350 FLOW ALONG WITH WEAK LAND BREEZE WAS KEEPING MOST OF THE LGT LES ALONG THE SHORELINE FROM BIG BAY TO MARQUETTE. ETA/GFS WERE IN REASONABLE AGREEMENT WITH RESPECT TO FEATURES AFFECTING UPR MI INTO THE WEEKEND WITH TREND TOWARD WEAKER SLOWER SHRTWV LATE FRI INTO SAT. TODAY...WITH LITTLE CHANGE IN THE FCST SNDGS OR WINDS TIL AFT 15Z...WL KEEP ADVY AND MENTION OF SOME -FZDZ THIS MORNING OVER NORTH CNTRL UPR MI AND NW UPR MI. ANY SNOW AMOUNTS SHOULD ONLY AMOUNT TO LESS THAN HALF AN INCH...GIVEN RADAR TRENDS AND VERY SHALLOW INSTABILITY. ONLY FLURRIES FCST NW WHERE FETCH IS SHORTER AND LLVL WIND MORE ACYC. ETA SUGGESTS SFC AND MID LVL SHRTWV RDG TO BUILD INTO THE WRN LAKES WITH SLOWLY BACKING WINDS AND LOWERING INVERSION AND DIMINISHING 900-800 MOISTURE. EXPECT ENOUGH DRYING IN LOWER LVLS TO MINIMIZE -FZDZ THREAT BY AFTERNOON. HOWEVER...ADVECTION SHOULD BE WEAK ENOUGH SO THAT SKIES REMAIN MOSTLY CLOUDY WITH LINGERING MOISTURE BLO 900 MB INVERSION. LIMITED INSOLATION WILL BRING ANOTHER DAY WITH LIMITED DIURNAL RANGE AS TEMPS REMAIN IN THE MID TO UPPER 20S AS REFLECTED BY GUIDANCE AND GOING FCST. TONIGHT...WAA AND 290K ISENTROPIC LIFT WILL BRING A BAND OF MID LVL MOISTURE WITH MAINLY AC INTO THE WRN LAKES KEEPING SKIES MOSTLY CLOUDY. THIS SHOULD LIMIT RADIATIONAL COOLING EXCEPT FOR LATE OVER THE WEST WHERE SOME CLEARING MAY DEVELOP. THURSDAY...MDLS BRING DRYING WITH WITH WRLY FLOW AS AREA FALLS UNDER INFLUENCE OF BLOCKING MID LVL RDGING BTWN NRN AND SRN STREAMS. WITH PARTLY TO MOSTLY SUNNY SKIES EXPECT BY AFTERNOON AND ADDITIONAL WARMING WITH DOWNSLOPE OVER CNTRL UPR MI...MAX TEMPS BOOSTED A NOTCH NEAR HIGHER ETA/NGM GUIDANCE. FRI INTO SAT...EVEN WITH WEAKER/SLOWER SHRTWV MDLS SUGGEST ENOUGH DPVA AND ASSOCIATED QG FORCING BY LATE FRI NIGHT INTO EARLY SAT TO SUPPORT AT LEAST LOW CHANCE POPS FOR -SHSN. WITH LIMITED MOISTURE AVBL AND NARROW BAND OF DEEPER MOISTURE DEPICTED...EXPECT LITTLE IF ANY ACCUMULATION. POTENTIAL FOR ANY LAKE ENHANCEMENT...WITH H8 TEMPS TO NEAR -8C...ALSO LOOKS LIMITED WITH ONLY BRIEF IF ANY CONNECTION WITH LOW AND MID LVL MOISTURE. SUN...MENTION OF -RA POSSIBILITY EXPANDED FOR SUN AS GFS/UKMET/CANADIAN SUGGEST THAT NRN STREAM SHRTWV WILL BE STRONG ENOUGH WITH SUFFICIENT HGT RISES AND LOW LVL WAA AHEAD OF THE FEATURE TO BRING POSSIBILITY OF LIQUID PCPN. TEMPS ALSO BOOSTED TO REFLECT THIS TREND. HOWEVER...MOST SIGNIFICANT PCPN WOULD LIKELY FALL INTO COLDER AIR AS -SN WHERE ISENTROPIC LIFT IS MAXIMIZED LEAVING LIGHTER OR NO PCPN TO THE SOUTH. BOTH -RA OR -SN LEFT IN FCST GIVEN AMOUNT OF UNCERTAINTY AT THIS TIME. .MQT...FREEZING DRIZZLE ADVY THIS MORNING MIZ004>006. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 307 AM EST WED DEC 25 2002 CENTRAL NEW YORKERS AND NORTHEAST PENNSYLVANIANS WHO RECEIVE SNOW BLOWERS...TRACTOR PLOWS...AND EVEN BIG SHOVELS TODAY WILL BE MOST GRATEFUL FOR THEM BY TONIGHT. MAJOR WINTER CYCLOGENESIS IS COMING TOGETHER THIS MORNING AS PRIMARY LOW OVER THE OHIO VALLEY MOVES TOWARD OCCLUSION. NO SIGN OF WEAKENING IN THE PRECIP SHIELD OR WARMING OF CLOUD TOPS YET...SO THIS TRANSITION WILL BE RAPID AND VIOLENT WHEN THE ENERGY TRANSFER IS MADE TO THE COAST. CONVECTION DEVELOPING IN THE WARM CONVEYOR IS A GOOD SIGN THAT SUBTROPICAL JET IS TURNING THE CORNER. PRES FALLS ALREADY NOTED WITH ONE LOW CENTER OFF THE CAROLINAS ONCE SOUTHERN JET COUPLES WITH THE POLAR JET ENTRANCE REGION...BOOM! ACCORDING TO MANY MODEL SOLUTIONS...WE ARE ABOUT 6 HOURS AWAY FROM THIS PROCESS. LATEST RUC MODEL PROGS POSITION NEW COASTAL BOMB IN BETWEEN THE 00Z ETA/GFS RUNS. ETA...ALTHOUGH STILL THE WESTWARD MODEL...HAS TRENDED MANY PARAMETERS SLIGHTLY EAST. STAGE IS SET NICELY...BUT ONLY AFTER THE TRANSFER WILL ALL THE DETAILS BECOME CLEAR. CURRENT INDICATIONS SHOW THAT GFS PLACEMENT MAY BE THE BEST...ALTHOUGH WITH 150+ METER 500 MB HEIGHT RISES OVER NEW ENGLAND...BEEFING UP A WEAKLY BLOCKING RIDGE....I JUST CAN'T RULE OUT THE FACT THAT ETA MAY BE ONTO A CHRISTMAS SURPRISE. THAT BEING THE WHOLE SYSTEM WILL TAKE A MORE WESTERLY TRACK. THIS HAS BEEN A TREND THIS SEASON. BOTH MODELS SHOW STRONG MIDLVL FRONTOGENETICAL FORCING AND INSTABILITY NECESSARY FOR BANDED SNOW AT THE SAME TIME AND ROUGHLY THE SAME PLACE...OVER ZONES EAST OF I-81 AND ALONG AND SOUTH OF I-88. ETA CAPTURES DETAILS SIGNIFICANTLY BETTER GIVEN IT'S RESOLUTION. CATSKILLS...SUSQUEHANNA REGION AND NORTHERN PENNSYLVANIA WILL BE UNDER THE PRIME POSITION RELATIVE TO 700 MB LOW TRACKS. SHARP SLOPE TO FRONTAL SYSTEM WILL MEAN STRONG VERTICAL MOTIONS. THUNDERSNOW A DISTINCT POSSIBILITY WITH SNOWFALL RATES 2-3" PER HOUR UNDER THE BAND(S). ALL WARNINGS AND THE ADVISORY WILL REMAIN THE SAME. THE ONLY CHANGES TO FORECAST THAT WILL BE MADE WILL BE TO BEGIN SLICING OFF ACCUMS FOR THE WESTERN AND NORTHERN COUNTIES FROM PREV FORECAST. CYCLONES OF THIS NATURE...PARTICULARLY WITH BANDING...HAVE VERY TIGHT SNOW GRADIENTS. I DON'T WANT TO GO TOO FAR AT THIS POINT AS 13-15:1 RATIOS ON THE QPF FIELDS WOULD STILL YIELD AT LEAST LOW END WARNING CRITERIA SNOW (7 INCHES) IN THE FINGER LAKES REGION AND CENTRAL SOUTHERN TIER. IF WE DON'T WRAP THE SYSTEM BACK NORTH AND WEST...NRN ONEIDA WILL BE THE ONLY PART OF OUR AREA RELATIVELY SPARED. REST OF SNOW AMOUNTS 12- 20" WILL STAND OVER NE PA AND SUSQ REGION...WRN CATSKILLS. WE ALSO MAY SALVAGE ANOTHER COUPLE INCHES FOR THE FINGER LAKES TONIGHT BEHIND THE SYSTEM AS LAKE ONTARIO ENHANCMENT KICKS IN ON THE NORTHWEST FLOW. CURRENT FORECAST BEYOND TODAY HANDLES THE CHANCE FOR SOME LAKE EFFECT SNOW GOING INTO THURSDAY FOLLOWED BY QUIETER WEATHER FOR THE WEEKEND. TEMPS FROM THE PREV FCST LOOK GOOD...SO ONLY MASSAGED WITH AVN/NGM MOS. .BGM...WINTER STORM WARNING THROUGH THIS EVENING FOR NORTHEAST PA. WINTER STORM WARNING THROUGH THIS EVENING FOR CENTRAL NY... EXCEPT NORTHERN ONEIDA COUNTY. WINTER WEATHER ADVISORY THROUGH THIS EVENING FOR NORTHERN ONEIDA COUNTY. BREWSTER ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 235 AM EST WED DEC 25 2002 SANTA BROUGHT US AN INSTANT OCCLUSION CYCLOGENESIS FOR CHRISTMAS... WHAT DID YOU GET? CYCLOGENESIS IN PROGRESS TO OUR SOUTH WITH CONVECTION FILLING IN BETWEEN THE CCB TO THE WEST OVER THE OHIO VALLEY AND THE WCB TO THE EAST OVER THE COASTAL ATLANTIC WATERS. AS STRONG ULJ ROUNDS THE BASE OF THE OHIO VALLEY TROF AND CONTINUES TO INTERACT WITH WCB...INSTANT OCCLUSION LOW WILL REFORM IN EAST CENTRAL VIRGINIA BETWEEN 12 AND 14 UTC AND TRACK UP ALONG NEW JERSEY COASTLINE WHILE RAPIDLY INTENSIFYING. 06 UTC RUC NOW INDICATES A FARTHER EASTWARD TRACK TO THE SURFACE LOW CLOSER TO THE COUPLED JET JUXTAPOSITION...HEADING OFF THE DELMARVA PENINSULA AND OUT TO SEA SOUTH OF NJ...THEN HEADING NORTHEASTWARD TOWARD CAPE COD. THIS WOULD KEEP THE HEAVIEST SNOWFALL OVER THE EASTERN THIRD OF PENNSYLVANIA... AS CURRENTLY FORECAST. TABLE IS SET NICELY THIS MORNING...AND WILL CONTINUE TO MONITOR EVOLUTION OF PRECIPITATION SHIELD AS THE OCCLUSION DEVELOPS AND MOVES SOUTHEAST OF THE AREA. EXPECT SNOW RATIOS TO REMAIN MOSTLY IN THE 10:1 TO 12:1 RANGE...OWING TO FAIRLY DEEP ISOTHERMAL SOUNDING STRUCTURE HOLDING A DEGREE OR TWO BELOW 0 C IN THE LOWEST SEVERAL THOUSAND FEET. EMBEDDED CONVECTIVE CELLS HOWEVER WILL PRODUCE 1 TO 2 INCH/HOUR SNOW BURSTS DURING THE MORNING AND EARLY AFTERNOON HOURS ACROSS CENTRAL AND EASTERN PA...WHICH SHOULD FURTHER ENSURE THAT CURRENT WARNINGS VERIFY. FOR THE NORTHWEST...STRONGEST FORCING FOR PRECIPITATION WILL BE MOVING THROUGH DURING THE NEXT 6 HOURS...AND AGREE WITH PREVIOUS SHIFT THAT WARNINGS MAY NEED TO BE SCALED BACK TO ADVISORIES SHOULD THE RUC SFC PROGS BE CORRECT IN TAKING THE LOW FURTHER EAST... LEAVING WARREN AND MCKEAN COUNTIES IN LESS FAVORABLE FORCING. NOT READY TO DOWNGRADE YET...AS LARGE AREA OF CONVECTIVE PRECIP IS NOW STREAMING NORTHWARD FROM THE CENTRAL APPALACHIANS TOWARDS SOUTHEAST OHIO AND WESTERN PA. CURRENT SNOWFALL AMOUNTS STILL LOOK QUITE GOOD AND SEE NO REASON TO ADJUST AT PRESENT TIME. STILL THINKING NORTHEAST COUNTIES COULD EXCEED ONE FOOT BY LATE THIS EVENING AS THE SFC LOW BOTTOMS OUT OFF THE NJ COAST. FOR THE LAST SEVERAL DAYS OF THE YEAR...EXPECT RELATIVELY QUIETER CONDITIONS WITH COLD NORTHWEST BOUNDARY LAYER FLOW PROMOTING SNOW SHOWERS AND FLURRIES OFF THE LAKES THURSDAY INTO FRIDAY. A REINFORCEMENT ARRIVES SATURDAY AS A WEAK COLD FRONT CROSSES THE REGION...AND CYCLOGENESIS TAKES PLACE ONCE AGAIN BUT THIS TIME MUCH TOO FAR EAST TO HAVE A SIGNIFICANT IMPACT ACROSS THE REGION... OTHER THAN MAINTAINING THE NORTHWEST FLOW AND ENHANCING LAKE EFFECT SNOW SHOWERS AND FLURRIES ONCE AGAIN. BROAD SOUTHWEST FLOW PROGGED TO BRING A WARMUP TO THE AREA FOR THE LAST 2 DAYS OF THE YEAR...WITH A CHANCE OF RAIN OR SNOW (MORE LIKELY RAIN AS IT LOOKS TO ME NOW) MONDAY INTO TUESDAY. WORK ZONES WL BE OUT BY 315 AM AS PHLWRKMIS. .CTP...WINTER STORM WARNING ENTIRE CWA. $$ DEVOIR pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ALBANY NY 1040 AM EST WED DEC 25 2002 .CURRENT...MAX FRONTOGEN FM RUC40 CORRELATES VERY WELL WITH RAPID INCREASE IN WSR88D RETURNS ACRS NEPA AND NJ. ALIGNS WELL WITH DEFORMATION AXIS AND ORIENTATION TO H700 MB HPA AND 300 HPA JET COUPLING AS PER RECENT CSTAR BANDING CONCEPTUAL MODEL. IN TERMS OF SENSIBLE WEATHER THIS WILL PROD FISRT SURGE OF HEAVY SNOW...LIFTING ACRS CATSKILLS 17-18Z TOWARD ALBANY EARLY THIS AFTERNOON. AXIS SHLD MV TO ALY AREA 18Z. WL ISSUE STRONGLY WORDED NOWCAST SNOW INCR TO 1-2 HR THEN 2-4"/HR SNYDER .PVS DISC... THE CURRENT WEATHER SITUATION IS ABOUT AS CLOSE TO PERFECT AS IT GETS FOR ANTECEDENT AND MODEL FORECAST PARAMETERS TO SPILL A LOT OF SNOW ACROSS MUCH OF ALBANY'S COUNTY WARNING AREA. THE LATEST RUN OF THE MODELS (0000 UTC WEDNESDAY), POINTS TO A HEAVY SNOWFALL IN THE BULK OF THE COUNTY WARNING AREA. THE ONLY AREA OF CONCERN IS THE NORTHWESTERN PERIPHERY OF THE COUNTY WARNING AREA (WESTERN MOHAWK VALLEY AND WESTERN ADIRONDACKS). THE ETA, MESOSCALE ETA, AVIATION AND CANADIAN REGIONAL MODEL WERE EXAMINED PRIOR TO THIS DISCUSSION. THE MAIN DIFFERENCE BETWEEN THE MODELS IS IN THE FORECAST AREA OF MAXIMUM PRECIPITATION AND THE PLACEMENT AND DEPTH OF THE SURFACE LOW. THE MULTI-LEVEL WIND CIRCULATION FORECAST SUGGEST A HIGH PROBABILITY OF HEAVY BANDED PRECIPITATION WITH THIS STORM. IT IS UNLIKELY THAT THE AVIATION, WITH ITS POORER RESOLUTION IS CAPTURING THIS. HOWEVER, IT IS STRONGLY SUGGESTED BY THE PRECIPITATION FORECAST OF THE MESOSCALE ETA WHICH INDICATES A RELATIVELY NARROW BAND OF HEAVY PRECIPITATION ACROSS THE NORTHERN CATSKILLS, CAPITAL DISTRICT INTO SOUTHERN VERMONT, THE NORTHERN TACONICS AND THE BERKSHIRES. THE AVIATION MODEL SUGGESTS THAT THE AXIS OF HEAVIEST PRECIPITATION WILL BE ALONG THE ATLANTIC COAST, AND INDEED, THIS MODEL DOES FORECAST THE LOW PRESSURE CENTER TO BE FURTHER TO THE SOUTH THAN THE MESOSCALE ETA, AND ALSO 5 OR 6 MILLIBARS DEEPER. THE AVIATION MODEL REALLY LOOSES ITS MARBLES BETWEEN 1200 UTC AND 1800 UTC TODAY WHEN IT DEEPENS AND 12 MILLIBARS. THE MESOSCALE ETA AND CANADIAN REGIONAL ARE CLOSE BEHIND DROPPING THE CENTER BY 10 MILLIBARS. THE CANADIAN MODEL'S PRECIPITATION FORECAST IS NOT AS STRONGLY SUGGESTIVE OF BANDED PRECIPITATION AS THE MESOSCALE ETA, BUT THEN AGAIN, ALL WE HAVE TO WORK WITH IS INTERNET MAPS, DIVIDED INTO CHUNKS OF 6-HOUR TIME PERIODS (MAYBE SOMEDAY WE'LL HAVE THE LUXURY OF LOOKING AT THIS MODEL IN AWIPS). BUT THIS MODEL IS INDICATING VERY HEAVY PRECIPITATION SOMEWHAT TO THE SOUTH OF THE MESOSCALE ETA FORECAST (ACROSS THE CENTRAL AND SOUTHERN CATSKILLS AND MID HUDSON VALLEY INTO THE BERKSHIRES, WHERE AND INCH OR MORE IS FORECAST BETWEEN 1800 UTC WEDNESDAY AND 0000 UTC THURSDAY. WE BELIEVE THAT THE MESOSCALE ETA AND CANADIAN MODELS HAVE THE BEST HANDLE ON WHERE THE HEAVY PRECIPITATION WILL BE OCCURRING IN THIS STORM. THE DEPTH OF THE LOW FORECAST BY THE CANADIAN REGIONAL MODEL IS SLIGHTLY DEEPER THAN THE MESOSCALE ETA, BUT NOT AS DEEP AS THE AVIATION. THE TRACK OF THE LOW IS VERY SIMILAR TO THE MESOSCALE ETA, AND BOTH MODELS ARE FURTHER NORTH THAN THE AVIATION. THE THREAT OF DIMINISHED SNOWFALL IN THE EXTREME SOUTHEASTERN PORTION OF THE COUNTY WARNING AREA IS NOW LESS THAN IT APPEARED TO BE ON MONDAY NIGHT'S MODEL FORECASTS. BOTH THE MESOSCALE ETA AND THE CANADIAN MODELS HAVE TRENDED COLDER. MESOSCALE ETA FORECAST SOUNDINGS ARE NOW SUGGESTING THAT THE ENTIRE SOUTHERN TIER OF ZONES IN ALBANY'S COUNTY WARNING AREA WILL REMAIN BELOW FREEZING THROUGH THE ENTIRE COLUMN. THE CANADIAN MODEL'S 850 MILLIBAR TO 700 MILLIBAR THICKNESS IS SHOWING THE 1540 METER ISOPLETH TO BE INTO CENTRAL DUTCHESS AND LITCHFIELD COUNTIES THIS MORNING AND EARLY THIS AFTERNOON, BUT THE ABOVE FREEZING LAYER REMAINS SOUTHWEST OF THE COUNTY WARNING AREA EARLY TODAY, AND THEN GETS WIPED OUT ENTIRELY THIS AFTERNOON. THIS SUGGESTS THAT VERY STRONG UPWARD MOTION AND HEAVY PRECIPITATION IN THE FORM OF SNOW IS COOLING THE COLUMN TO BELOW FREEZING IN THE ELEVATED ABOVE FREEZING LAYER. SO, IT IS UNLIKELY THAT THERE WILL BE ANY SLEET IN THE SOUTHERN ZONES TODAY, AND IT IS LIKELY THAT SLEET WILL NOT BE MENTIONED IN THE FORECAST THAT IS RELEASED LATER THIS MORNING. THE CURRENT ZONE FORECASTS LOOK FINE OVERALL. THE MAIN CONCERN IS THAT THE PRECIPITATION IN THE NORTHWEST WILL NOT BE HEAVY ENOUGH TO RESULT IN 7 INCHES OF SNOW. HOWEVER, THIS IS THE REGION WHEN THE AIR IS COLDEST, AND PERHAPS THE LIQUID TO SNOW RATIO WILL BE GREATEST THERE. ALSO, THERE IS THE OROGRAPHIC ENHANCEMENT TO CONSIDER, SO THE WINTER STORM WARNING WILL BE LEFT IN PLACE IN ALL ZONES. THE LOW'S EASTWARD MOVEMENT IS FORECAST TO SLOW BETWEEN 0000 UTC AND 0600 UTC THURSDAY BY THE CANADIAN MODEL. AND THE MESOSCALE ETA IS FORECASTING 90 PERCENT OR BETTER RELATIVE HUMIDITY THROUGH 700 MILLIBARS THROUGH MUCH OF THE NIGHT WITH SOME UPWARD MOTION. TRADITIONALLY, THE BERKSHIRES, TACONICS AND SOUTHERN GREEN MOUNTAINS PICK UP CONSIDERABLE TRIMMINGS ON THE BACKSIDE OF THESE COASTAL STORMS, AND IT IS BELIEVED THAT THIS WILL BE THE CASE TONIGHT AS WELL. SO, WARNING CRITERION IS EXPECTED TO BE MET TO THE EAST OF THE CAPITAL DISTRICT TONIGHT WITH AT LEAST ANOTHER 7 INCHES OF SNOW, WHILE TO THE WEST, IT'S LIKELY TO BE LESS. THE WARNING WILL BE CONTINUED INTO TONIGHT IN ALL ZONES. TODAY'S HIGH TEMPERATURES WILL BE BELOW FREEZING IN ALL LOCATIONS, AND PROBABLY AT LEAST 5 DEGREES BELOW FREEZING IN MOST ZONES. TONIGHT'S LOWS MAY BE 5 OR 10 DEGREES LOWER, BUT THERE WON'T BE A LOT OF COLD ADVECTION AT THE SURFACE AND MINIMAL RADIATIONAL COOLING. THE AVIATION-BASED STATISTICAL FORECAST LOOKS TOO HIGH FOR TODAY'S TEMPERATURES, BUT ABOUT RIGHT ON THURSDAY. THE NESTED-GRID FORECAST SEEMS BETTER FOR TODAY. A WINTER WEATHER EXPERIMENTAL CHAT IS SCHEDULED FOR 1245 AM, WHICH ALBANY'S OFFICE WILL PARTICIPATE IN. ANY CHANGES FROM WHAT THIS DISCUSSION INDICATES ARE LIKELY TO RESULT FROM THAT CHAT. IF THERE ARE ANY SIGNIFICANT CHANGES, ANOTHER DISCUSSION WILL BE ISSUED BEFORE RELEASING THE FORECAST LATER THIS MORNING. HOPE YOU'RE GETTING A NEW SNOWBLOWER FOR A HOLIDAY GIFT. .HYDROLOGICAL STATUS...WITH ONLY WINTER-TYPE PRECIPITATION IN THE CARDS, NO PROBLEMS THROUGH THE END OF THE WEEK. .ALY...WINTER STORM WARNINGS FOR THE ENTIRE COUNTY WARNING AREA CHRISTMAS AND WEDNESDAY NIGHT. ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1050 AM EST WED DEC 25 2002 MSAS/RUC AND QUICK LOOK AT THE NEW MESO ETA ALL INDICATE THAT THE SFC LOW TRACK NEAR THE MD COAST THIS MORNING WILL TRACK ALMOST DUE NORTH TO NEAR ACY EARLY THIS AFTERNOON. CURRENT RUC/MESO-ETA FRONTOGENESIS PATTERNS ARE CURRENTLY MATCHING WELL WITH AN AREA OF HEAVY PRECIPITATION OVER EASTERN PA INTO CENTRAL NY. THE RUC AND MESO-ETA BOTH INDICATE THAT THIS AREA OF ENHANCED FRONTOGENESIS WILL REMAIN ACROSS EASTERN PA AND CENTRAL NY THROUGH EARLY AFTERNOON...THEN SLOWLY SHIFT OFF TO THE NORTHEAST THIS AFTERNOON. RUC/MESO-ETA CROSS-SECTION ANALYSIS ARE ALSO INDICATING A GOOD INSTABILITY SIGNATURE WITH A LAYER OF NEGATIVE EPV LOCATED IN THE LAYER JUST ABOVE THE FRONTOGENESIS AROUND 500 TO 600 MB. THE NEW 12Z MESO-ETA TAKES THESE SIGNATURES AND PRODUCING NEARLY AN INCH OF QPF OVER NE PA AND THE SOUTHERN TIER BETWEEN 15Z AND 18Z. THIS MAY BE SLIGHTLY OVERDONE...BUT BOTTOM LINE IS VERY HEAVY SNOW FOR ALL OF THE CWA THROUGH EARLY AFTERNOON. ONE PROBLEM EARLIER THIS MORNING WAS SOME STUBBORN FREEZING RAIN AND SLEET AT AVP...BUT THAT HAS NOW TURNED TO SNOW AS HEAVIER PRECIPITATION HAS WORKED IN. MODEL SOUNDINGS SHOW NOTHING BUT COOLING FROM NOW ON SO EXPECT NO PROBLEMS WITH MIXED PRECIP THRU THE REST OF THE DAY. BUFKIT SOUNDINGS SHOWING A MODERATELY DEEP LAYER OF FAVORABLE SNOW GROWTH...MAINLY ABOVE 10 KFT...BUT WELL WITHIN A LAYER OF STRONG LIFT. BOTTOM LINE WITH ALL OF THIS IS THAT HEAVY SNOW LOOKS LIKELY FOR ALL OF THE CWA. WARNINGS CURRENTLY IN PLACE WILL REMAIN IN PLACE. ADVISORY OVER NORTHERN ONEIDA COUNTY WILL REMAIN IN PLACE AS WELL AS THE MESO-ETA...WHICH IS THE WETTEST...FARTHEST NORTH MODEL THAT WE HAVE IS SHOWING HALF TO THREE QUARTERS OF AN INCH OF QPF IN THAT AREA. OVERALL PROBABLY WILL JUST NEED TO TWEAK SOME SNOW AMOUNTS HERE AND THERE...AND BASED ON THE LIKELYHOOD OF VERY INTENSE BANDING OVER THE NEXT 6 HOURS WILL MENTION SOME LOCALIZED 2 FOOT AMOUNTS OVER THE EASTERN CWA. THANKS TO CTP AND PHI FOR COORD. .BGM...WINTER STORM WARNING THROUGH THIS EVE FOR ALL OF THE CWA EXCEPT A WINTER WEATHER ADVISORY THRU THIS EVENING FOR NORTHERN ONEIDA COUNTY. MSE ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 945 AM EST WED DEC 25 2002 WATER VAPOR IMAGERY SHOWS THE NOSE OF A 120 KT 300 HPA JET ALONG THE MID ATLANTIC COAST JET WRAPPING MOIST/UNSTABLE AIR WESTWARD ACROSS MUCH OF THE SUSQUEHANNA VALLEY AND CENTRAL MOUNTAINS WHERE THE STRONGEST 850-700 HPA FRONTOGENESIS IS CURRENTLY LOCATED. SNOWFALL RATES OF OVER 2 INCHES PER HOUR (4.8" OUTSIDE OUR OFFICE HERE BETWEEN 7 AND 9 AM WITH THUNDER REPORTED JUST TO OUR WEST SHORTLY AFTER 7 AM). STRONG NEG TILT SHORT WAVE LIFTING ENE FROM WVA (WITH THE PRIMARY UPPER LOW JUST SOUTH OF COLUMBUS OHIO) WILL MEAN A LIKELY EVOLUTION FROM NON-UNIFORM AREAS OF MDT TO HVY SNOW -> BROADER MORE ORGANIZED MODERATE/HVY SNOW...WITH WELL DEFINED NE/SW ORIENTED 35-45 DBZ CSI SNOW BANDS FROM JUST EAST OF KUNV...THROUGH THE CENTRAL SUSQ AND PARTS OF THE LOWER SUSQ REGION...ON TO THE EAST NORTHEAST OVER SCHUYLKILL COUNTY AND THE POCONOS. DEEPENING 500 HPA LOW TRACK ACROSS THE SRN BORDER OF PENN AND SLOW MOVING INTENSIFYING 850 HPA CENTER FROM JUST S OF KPHI AT 15Z & 18Z TO JUST SE OF NYC AT 21Z CONFIRMS THE ABOVE NOTED TARGET AREA FOR HEAVIEST SNOW. WILL TWEAK TOTAL STORM SNOWFALL AMOUNTS UP A BIT ACROSS THE CENTRAL AND WESTERN ZONES AS LIGHT TO MODERATE SNOWFALL RATES WILL CONTINUE THROUGH MUCH OF THE DAY...AMOUNTING TO ANOTHER 0.20" TO 0.40" LIQ EQUIVALENT (2-4 INCHES OF ADDITIONAL SNOW...LOCALLY HIGHER AMOUNTS OF 5 OR 6 INCHES FROM LAKE ENHANCEMENT ACROSS THE EXTREME NW MTNS NEAR QUASI-STNRY OCCLUDED FRONT). NCENTRAL MTNS AND CENTRAL SUSQ LOOK IN THE BALLPARK FOR A GENERAL 8 TO 12 INCHES OF SNOW...THOUGH LOCALLY 14 INCHES IS POSSIBLE. SCHUYLKILL COUNTY...AND NORTH INTO COLUMBIA AND SULLIVAN COUNTY WILL RECEIVE THE HIGHEST SNOWFALL TOTALS AVERAGING 12 TO 15 INCHES. THE FINAL TROUBLE SPOT IS THE LOWER SUSQ...AND OUR EXTREME SE COUNTIES WHERE A VERY SHARP GRADIENT OF SNOWFALL WILL OCCUR AS THE RAIN/SNOW LINE MIGRATES SLOWLY EAST (RAIN JUST CHANGED TO WET SNOW IN KLNS DURING THE PAST HOUR) SO...FOR SIMPLIFICATION AND MORE USEFUL TRAVEL INFORMATION...I WILL GROUP MUCH OF THE LOWER SUSQ REGION TOGETHER FOR THE ZONE TEXT AND SPECIFY A RANGE OF ACCUMULATIONS (HIGHEST AMOUNTS OF UP TO 10 INCHES WILL FALL JUST NW OF INTERSTATE 81...WITH AS LITTLE AS 5 INCHES ACROSS SRN LANCASTER COUNTY WHERE SOME MIXED PRECIP MAY STILL OCCUR AND SNOW/WTR RATIOS WILL BE LOWEST). SNOW WILL TAPER OFF LATE TODAY...THEN END IN MOST AREAS THIS EVENING. LAKE EFFECT SNOW SHOWERS WILL CONTINUE OVER THE NRN AND WESTERN MTNS TONIGHT...WITH NW WINDS STEADILY INCREASING IN ALL AREAS. NO CHANGE IN CURRENT WINTER STORM WARNINGS BLANKETING THE ENTIRE CWFA THROUGH THIS AFTERNOON. MERRY...RECORD...WHITE CHRISTMAS!! ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ PREVIOUS DISCUSSION BELOW ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ SANTA BROUGHT US AN INSTANT OCCLUSION CYCLOGENESIS FOR CHRISTMAS... WHAT DID YOU GET? CYCLOGENESIS IN PROGRESS TO OUR SOUTH WITH CONVECTION FILLING IN BETWEEN THE CCB TO THE WEST OVER THE OHIO VALLEY AND THE WCB TO THE EAST OVER THE COASTAL ATLANTIC WATERS. AS STRONG ULJ ROUNDS THE BASE OF THE OHIO VALLEY TROF AND CONTINUES TO INTERACT WITH WCB...INSTANT OCCLUSION LOW WILL REFORM IN EAST CENTRAL VIRGINIA BETWEEN 12 AND 14 UTC AND TRACK UP ALONG NEW JERSEY COASTLINE WHILE RAPIDLY INTENSIFYING. 06 UTC RUC NOW INDICATES A FARTHER EASTWARD TRACK TO THE SURFACE LOW CLOSER TO THE COUPLED JET JUXTAPOSITION...HEADING OFF THE DELMARVA PENINSULA AND OUT TO SEA SOUTH OF NJ...THEN HEADING NORTHEASTWARD TOWARD CAPE COD. THIS WOULD KEEP THE HEAVIEST SNOWFALL OVER THE EASTERN THIRD OF PENNSYLVANIA... AS CURRENTLY FORECAST. TABLE IS SET NICELY THIS MORNING...AND WILL CONTINUE TO MONITOR EVOLUTION OF PRECIPITATION SHIELD AS THE OCCLUSION DEVELOPS AND MOVES SOUTHEAST OF THE AREA. EXPECT SNOW RATIOS TO REMAIN MOSTLY IN THE 10:1 TO 12:1 RANGE...OWING TO FAIRLY DEEP ISOTHERMAL SOUNDING STRUCTURE HOLDING A DEGREE OR TWO BELOW 0 C IN THE LOWEST SEVERAL THOUSAND FEET. EMBEDDED CONVECTIVE CELLS HOWEVER WILL PRODUCE 1 TO 2 INCH/HOUR SNOW BURSTS DURING THE MORNING AND EARLY AFTERNOON HOURS ACROSS CENTRAL AND EASTERN PA...WHICH SHOULD FURTHER ENSURE THAT CURRENT WARNINGS VERIFY. FOR THE NORTHWEST...STRONGEST FORCING FOR PRECIPITATION WILL BE MOVING THROUGH DURING THE NEXT 6 HOURS...AND AGREE WITH PREVIOUS SHIFT THAT WARNINGS MAY NEED TO BE SCALED BACK TO ADVISORIES SHOULD THE RUC SFC PROGS BE CORRECT IN TAKING THE LOW FURTHER EAST... LEAVING WARREN AND MCKEAN COUNTIES IN LESS FAVORABLE FORCING. NOT READY TO DOWNGRADE YET...AS LARGE AREA OF CONVECTIVE PRECIP IS NOW STREAMING NORTHWARD FROM THE CENTRAL APPALACHIANS TOWARDS SOUTHEAST OHIO AND WESTERN PA. CURRENT SNOWFALL AMOUNTS STILL LOOK QUITE GOOD AND SEE NO REASON TO ADJUST AT PRESENT TIME. STILL THINKING NORTHEAST COUNTIES COULD EXCEED ONE FOOT BY LATE THIS EVENING AS THE SFC LOW BOTTOMS OUT OFF THE NJ COAST. FOR THE LAST SEVERAL DAYS OF THE YEAR...EXPECT RELATIVELY QUIETER CONDITIONS WITH COLD NORTHWEST BOUNDARY LAYER FLOW PROMOTING SNOW SHOWERS AND FLURRIES OFF THE LAKES THURSDAY INTO FRIDAY. A REINFORCEMENT ARRIVES SATURDAY AS A WEAK COLD FRONT CROSSES THE REGION...AND CYCLOGENESIS TAKES PLACE ONCE AGAIN BUT THIS TIME MUCH TOO FAR EAST TO HAVE A SIGNIFICANT IMPACT ACROSS THE REGION... OTHER THAN MAINTAINING THE NORTHWEST FLOW AND ENHANCING LAKE EFFECT SNOW SHOWERS AND FLURRIES ONCE AGAIN. BROAD SOUTHWEST FLOW PROGGED TO BRING A WARMUP TO THE AREA FOR THE LAST 2 DAYS OF THE YEAR...WITH A CHANCE OF RAIN OR SNOW (MORE LIKELY RAIN AS IT LOOKS TO ME NOW) MONDAY INTO TUESDAY. WORK ZONES WL BE OUT BY 315 AM AS PHLWRKMIS. DEVOIR +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ .CTP...WINTER STORM WARNING CONTINUED FOR THE ENTIRE CWA THROUGH THIS AFTERNOON. LAMBERT $$ pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 217 PM EST WED DEC 25 2002 .DISC...WELL YOU WONT HAVE TO DREAM ABOUT A WHITE CHRISTMAS HERE. MJR WINTER STORM WILL AFFECT FCA INTO THE EVENING. 1-2 FEET LIKELY. .SHORT TERM...MAX FRONTOGEN FM RUC40/WSETA CORRELATES VERY WELL WITH RAPID INCREASE IN WSR88D RETURNS FM W CTSKLS TO S BERK CTY WITH NEW AREA RAPIDLY LIFTING NNW FM MID HUD VLY TO N CT. HAVE HAD REPORTS OF HVY IP AND ZR MIXED IN SE ZNS...BUT THESE SEEM TO HAVE DIM AS MST RECENT REPORTS HV HVY SNOW IN AREA OF 50DBZ RETURN AND REPORTS OF FLAKES THE SIZE OF QUARTERS. THIS MRNG REPORTS OF THUNDER AND LIGHTING DETECTION SYS SHOWING NUMEROUS STRIKES OFFSHORE AND SEVERAL ACROSS N NJ AND SE NY. IN ANY CASE HVY SNOW ALIGNS WELL WITH DEFORMATION AXIS AND ORIENTATION TO H700 MB HPA AND 300 HPA JET COUPLING AS PER RECENT CSTAR BANDING CONCEPTUAL MODEL. APPEAR TO BE 3 BANDS MOVING INLAND FM SSE TO NNW. CLOUD TOP COOLING CONTS ACRS RGN IN DCVA AND LOOKS LIKE THE UPR LVL CUT OFF IS IN PROCESS OF CAPTURING THE WRM CONVEYOR BELT INFLOW THATS OFFSHORE. SFC LOW IS GOING THRU BOMBOGENISUS OFF NJ WITH PRES FALLS EXCEEDING 10 MB/HR NOW OVR E LONG IS...AND SFC PRESSURE DOWN TO 978 MB AS SFC LOW JUST OFF BARNEGATT BAY NJ. DRNG AFTN SFC LOW WL BE CAPTURED BY UP LEVEL SYSTEM WITH RAPIDLY SHORTENING WV LENGTHS AND EXPLOSIVE UVM. ALL MDLS FAIRLY CONSISTENT WITH EVENT AS HEAVY SNOW FROM RAPIDLY DEEPENING LOW AND BANDING PRODUCES AMNTS OF 1-3 INCHES/ HR AND AT TIMES 2-4 IN/HR INTO THE EARLY EVENING. LOWERED AMTS A TAD SE DUE TO AMNT OF IP THAT WAS OCCURRING THIS MORNING...BUT DYNAMIC COOLING SEEMS TO HAVE TAKEN CARE OF THE FEW WARM PATCHES CIRCULATING AROUND RGN AND PTYPE HAS CHANGES TO HVY SNOW IN CT. SO ALL AND ALL CURRENT FCST AMNTS LOOK GOOD AND WILL HOLD WITH GEN 1-2 FEET LIKELY. TNGT THE ENTIRE SYSTEM DESPITE BEING ALMOST VERTICAL...MVS E...TO GULF OF MAINE BY MORNING. HEAVIER SNOW WL CONT TO 01-03Z THEN DIM TO LT SNOW WHICH WL END FM NW TO SE TWRD MRNG. .LONG TERM...AFTR TDYS STORM WX PRETTY QUIET AND MDLS FAIRLY CONSISTENT. THURSDAY THE INTENSE SFC SYSTEM WL BE WELL OUT TO SEA BUT IT WL STILL HV STRONG WIND GRAD ACRS FCA. RESIDUAL LOW LEVEL MOISTURE WILL KEEP CLOUDS OVER HIGHER TERRAIN...ALONG WITH SCT -SHSN IN ADRDKS AND CATSKLS. FRI WK BNDRY NW-SE ACRS N TIER OF ZNS MAY ENHACE SCT -SHSN BUT IT LIFTS QUICKLY AWAY DRNG DAY. FRI NT A WK SHRT WV MVS FM THE MIDWEST TWRD FCA WITH INCR CLDS. .HYDROLOGICAL STATUS...WITH ONLY WINTER-TYPE PRECIPITATION IN THE CARDS, NO PROBLEMS THROUGH THE END OF THE WEEK. .ALY...WINTER STORM WARNINGS FOR THE ENTIRE COUNTY WARNING AREA THROUGH TONIGHT. SNYDER ny