AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1005 AM EST THU DEC 8 2005 .DISCUSSION... CURRENT...ALTHOUGH THE WARM FRONT IS NOT THAT WELL-DEFINED IN THE SFC T/TD/WIND FIELDS...I THINK IT'S SAFE TO ASSUME THAT IT LIES NEAR THE SRN EDGE OF THE STRATIFORM RAIN AND MULTILAYERED CLOUD SHIELD. THIS IS ROUGHLY ALONG A KPGD-KOKE-KSUA LINE...CORRESPONDING TO WHERE ISENTROPIC ASCENT IS MINIMAL TO NIL AND WHERE HPC ANALYZED IT AT 12Z. 12Z RAOBS FROM TBW/XMR SHOW HIGHEST PWATS (~1.75") LIE WITHIN THE SATURATED AIR MASS IMMEDIATELY NORTH OF THE WARM SECTOR...WHILE TO THE SOUTH EYW/MFL ARE ABOUT HALF AN INCH DRIER...MAINLY FROM THE MID LEVELS ON UP. MID LEVEL WAA/ISENTROPIC ASCENT SHOWS UP ON THE RAOBS AND PROFILER DATA AS WELL AS THE RUC ANLYS FIELDS. ONLY ISOLD-SCT CELLULAR CONVECTION NOTED WITHIN THE WARM SECTOR ON THE KAMX 88D. FCST...BEST MOISTURE/FORCED ASCENT WILL REMAIN NORTH OF THE WARM FRONT...WHICH WILL CONTINUE TO LIFT NWD AS THE GOMEX LOW EDGES EWD TODAY. LOOKS LIKE THE ADJUSTMENTS MADE BY THE MID SHIFT TO TAPER POPS A LITTLE MORE ACROSS THE SOUTH WILL WORK OUT NICELY...GIVEN CURRENT RADAR TRENDS. NO ZFP CHGS SEEMS TO BE NEEDED AT THIS TIME. && .MARINE...WILD RIDE CONTINUES ON THE ATLC WITH SUSTAINED WINDS 25-30KT GUSTING AS HIGH AS 40KT. GALE FORCE GUSTS NOTED EARLIER OVERNIGHT AS FAR SOUTH AS SPGF1...WHICH IS STILL BLOWING SUSTAINED CLOSE TO 25KT. CURRENT FCST LOOKS FINE...ONLY CHG WILL BE TO EXTEND THE GLW ACROSS THE SRN LEG INTO THE AFTN...AS THERE WILL PROBABLY BE SOME GALE FORCE GUSTS SOUTH OF COCOA BEACH THRU MID AFTN. && .AVIATION...WIDESPREAD MVFR WITH OCNL IFR CONDITIONS TODAY DUE TO REDUCED CIGS/VSBYS IN RAIN AND FOG. SOME GRADUAL IMPROVEMENT FROM SOUTH TO NORTH BY THIS EVENING. && .MLB WATCHES/WARNINGS/ADVISORIES... HIGH SURF ADVISORY FLAGLER BEACH-JUPITER INLET. GALE WARNING FLAGLER BEACH-COCOA BEACH UNTIL 7PM. GALE WARNING COCOA BEACH-JUPITER INLET UNTIL 4PM. && $$ CRISTALDI fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 820 PM CST THU DEC 8 2005 .DISCUSSION...LATEST SURFACE ANALYSIS HAD A DEEPENING AREA OF LOW PRESSURE CENTERED OVER CENTRAL INDIANA. A COLD FRONT EXTENDED SOUTH FROM THIS LOW TOWARD THE GULF COAST AND A TROF EXTENDED NORTHWEST FROM THE LOW INTO THE UPPER MIDWEST. ALOFT...A VIGOROUS UPPER LOW WAS CENTERED OVER CENTRAL ILLINOIS. SNOW/FLURRIES WILL RAPIDLY COME TO AN END AS THE SURFACE/UPPER SYSTEMS DEPART...LEAVING CLOUDS... LOW TEMPERATURES AND THE POTENTIAL FOR DRIFTING SNOW AS THE MAIN OVERNIGHT CONCERNS. DUE TO DIMINISHING SNOWS...WILL EXPIRE/CANCEL REMAINING ADVISORIES BY 9 PM. DEEPENING SURFACE LOW AND POST FRONTAL SUBSIDENCE HAS RESULTED IN HIGHER WINDS THAN PREVIOUSLY FORECAST...RESULTING IN SOME BLOWING AND DRIFTING OF THE DAY/S SNOW. THE WINDS SHOULD TAPER OFF BY MORNING AS THE PRESSURE GRADIENT AND SUBSIDENCE DIMINISHES...BUT WILL ADD A MENTION OF BLOWING/DRIFTING TO GRIDS/ZONES UNTIL THEN. THE WINDS WILL HOLD LOW TEMPERATURES UP A BIT MORE THAN WOULD BE EXPECTED WITH A FRESH SNOW PACK. HOWEVER...WE SHOULD HAVE A FEW HOURS FOR TEMPERATURES TO CRASH LATE TONIGHT AS THE WINDS SLACKEN AND THE REMAINING CLOUDS LOW CLOUDS UNDER THE UPPER LOW DEPART. && .PREV DISCUSSION... SHORT TERM CONCERN WILL BE WITH EXISTING HEADLINES THIS EVENING AND ADDITIONAL SNOWFALL...ESP ACRS THE EAST...WITH LONGER TERM CONCERNS REVOLVING AROUND TROF FCST TO DROP SEWD INTO THE LAKES OVER THE WEEKEND. IMPRESSIVE UPPER LOW NOW OVER SOUTHWEST IOWA BECOMING MORE NEGATIVELY TILTED WITH SECONDARY SPEED MAX OF 140 KTS NOTED ON PROFILERS ACR SRN MISSOURI. ILX RADAR INDICATING SEVERAL MESOSCALE SNOW BANDS PUSHING NORTH ACRS THE FCST AREA. ONE SUCH BAND NOW PUSHING NE OF LINCOLN THRU BLOOMINGTON EAST THROUGH THE INTERSTATE 57 CORRIDOR...WITH A SECONDARY BAND LOCATED JUST WEST OF SPRINGFIELD. WL KEEP HEADLINES GOING INTO THIS EVENING WITH MOST SIGNIFICANT SNOWFALL FROM THIS SYSTEM MAINLY OCCURRING ALONG AND EAST OF INTERSTATE 55. NOT TOO MUCH TO ARGUE ABOUT MODEL-WISE...AT LEAST IN THE SHORT TERM...WITH SOME DIFFERENCES NOTED WITH WEEKEND SHORTWAVE AND ASSOCIATED PRECIP CHANCES. .SHORT TERM...TONIGHT THROUGH SATURDAY LATEST RUC MODEL SUGGESTING BEST 850-500 MB FORCING TO SHIFT INTO EXTREME EASTERN ILLINOIS BY 00Z. ETA MODEL INDICATING SOME WEAK PVU AND IMPRESSIVE QG FRONTOGENESIS IN THE TIME FRAME FROM 18Z-00Z FROM JUST EAST OF SPI THRU MTO AND SALEM WHERE SEVERAL MESOSCALE BANDS HAVE ALREADY OCCURRED. SNOWFALL REPORTS TO OUR WEST HAVE INDICATED AROUND 2 INCHES HAVE ALREADY OCCURRED AND WOULDN/T BE SURPRISED IF WE SEE A 4 INCH REPORT ACRS OUR EAST BY MID AFTERNOON. LARGE SCALE FORCING SHOULD SHIFT TO OUR EAST BY LATE THIS EVENING HOWEVER LINGERING FLURRIES SHOULD OCCUR IN 850 AND 500 MB THERMAL TROF THRU AT LEAST MIDNIGHT. BIG PROBLEM WILL BE WITH DEFORMATION ZONE PRECIP AND CLOUD SHIELD WHICH MODELS SUGGEST MAY SNEAK TO OUR NORTH AND EAST AFTER MIDNIGHT...MAKING A BIG DIFFERENCE IN THE OVERNIGHT LOW TEMPS. CURRENT FCST HAS GONE WELL BELOW GUID AND WL MAKE ONLY MINOR ADJUSTMENTS TO THE OVERNIGHT LOWS. QUIET WX RETURNS TO CNTRL IL FOR FRIDAY AND AT LEAST THE START OF THE WEEKEND AS HIGH PRESSURE PUSHES ACRS THE SRN MIDWEST. 850 MB THERMAL TROF WILL SHIFT TO OUR EAST AS WELL WITH TEMPERATURES WARMING QUITE A BIT...AT LEAST ALOFT. WILL PROBABLY GO A CATEGORY OR TWO BELOW GUID ON FRIDAY...DESPITE THE SUN AND SOUTHERLY WINDS. SAME CAN BE SAID FOR FRIDAY NIGHT AS MOSTLY CLEAR SKIES WILL ALLOW TEMPS TO DROP BELOW GUID. TROF FCST TO DEEPEN IN AGAIN ACRS THE LAKES REGION OVER THE WEEKEND WITH SVL SPOKES OF VORTICITY TRACKING ACRS THE FCST AREA. ABOUT ENOUGH TO PRODUCE SCATTERED FLURRIES AND THAT IS ABOUT IT. SOME COLDER AIR FILTERING IN AT 850 MB BUT WE HAVE SEEN IT QUITE A BIT COLDER ACRS THE AREA IN THE PAST SVL DAYS. BUT WITH A FRESH SNOW COVER...STILL THINKING GUID IS TOO OPTIMISTIC SO WL CUT IT BACK A SEVERAL DEGREES. LONG TERM...SUNDAY THROUGH THURSDAY... WL USE A BLEND BETWEEN THE ECMWF AND GFS IN THE LONGER TERM WITH THE GREAT LAKES TROF FCST TO MOVE EAST OF THE AREA BY TUESDAY. STILL FEEL MEX GUID A BIT TOO AGGRESSIVE WITH THE WARMING NEXT WEEK AS FLOW FLATTENS OUT SOME ACRS THE MIDWEST. THAT WILL BE TEMPORARY AS ADDL SHORTWAVE ENERGY IS FCST TO TRACK SE OUT OF SW CANADA BY NEXT WED AND POSSIBLY INFLUENCE A SRN STREAM WAVE. THAT MAY BRING PRECIP BACK INTO OUR NECK OF THE WOODS BY LATE NEXT WEEK...BUT TIMING OF THAT EVENT TOO MUCH IN DOUBT TO PUT IN GRIDS AT THIS TIME. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BAK/SMITH il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 215 PM CST THU DEC 8 2005 .DISCUSSION... SHORT TERM CONCERN WILL BE WITH EXISTING HEADLINES THIS EVENING AND ADDITIONAL SNOWFALL...ESP ACRS THE EAST...WITH LONGER TERM CONCERNS REVOLVING AROUND TROF FCST TO DROP SEWD INTO THE LAKES OVER THE WEEKEND. IMPRESSIVE UPPER LOW NOW OVER SOUTHWEST IOWA BECOMING MORE NEGATIVELY TILTED WITH SECONDARY SPEED MAX OF 140 KTS NOTED ON PROFILERS ACR SRN MISSOURI. ILX RADAR INDICATING SEVERAL MESOSCALE SNOW BANDS PUSHING NORTH ACRS THE FCST AREA. ONE SUCH BAND NOW PUSHING NE OF LINCOLN THRU BLOOMINGTON EAST THROUGH THE INTERSTATE 57 CORRIDOR...WITH A SECONDARY BAND LOCATED JUST WEST OF SPRINGFIELD. WL KEEP HEADLINES GOING INTO THIS EVENING WITH MOST SIGNIFICANT SNOWFALL FROM THIS SYSTEM MAINLY OCCURRING ALONG AND EAST OF INTERSTATE 55. NOT TOO MUCH TO ARGUE ABOUT MODEL-WISE...AT LEAST IN THE SHORT TERM...WITH SOME DIFFERENCES NOTED WITH WEEKEND SHORTWAVE AND ASSOCIATED PRECIP CHANCES. .SHORT TERM...TONIGHT THROUGH SATURDAY LATEST RUC MODEL SUGGESTING BEST 850-500 MB FORCING TO SHIFT INTO EXTREME EASTERN ILLINOIS BY 00Z. ETA MODEL INDICATING SOME WEAK PVU AND IMPRESSIVE QG FRONTOGENESIS IN THE TIME FRAME FROM 18Z-00Z FROM JUST EAST OF SPI THRU MTO AND SALEM WHERE SEVERAL MESOSCALE BANDS HAVE ALREADY OCCURRED. SNOWFALL REPORTS TO OUR WEST HAVE INDICATED AROUND 2 INCHES HAVE ALREADY OCCURRED AND WOULDN'T BE SURPRISED IF WE SEE A 4 INCH REPORT ACRS OUR EAST BY MID AFTERNOON. LARGE SCALE FORCING SHOULD SHIFT TO OUR EAST BY LATE THIS EVENING HOWEVER LINGERING FLURRIES SHOULD OCCUR IN 850 AND 500 MB THERMAL TROF THRU AT LEAST MIDNIGHT. BIG PROBLEM WILL BE WITH DEFORMATION ZONE PRECIP AND CLOUD SHIELD WHICH MODELS SUGGEST MAY SNEAK TO OUR NORTH AND EAST AFTER MIDNIGHT...MAKING A BIG DIFFERENCE IN THE OVERNIGHT LOW TEMPS. CURRENT FCST HAS GONE WELL BELOW GUID AND WL MAKE ONLY MINOR ADJUSTMENTS TO THE OVERNIGHT LOWS. QUIET WX RETURNS TO CNTRL IL FOR FRIDAY AND AT LEAST THE START OF THE WEEKEND AS HIGH PRESSURE PUSHES ACRS THE SRN MIDWEST. 850 MB THERMAL TROF WILL SHIFT TO OUR EAST AS WELL WITH TEMPERATURES WARMING QUITE A BIT...AT LEAST ALOFT. WILL PROBABLY GO A CATEGORY OR TWO BELOW GUID ON FRIDAY...DESPITE THE SUN AND SOUTHERLY WINDS. SAME CAN BE SAID FOR FRIDAY NIGHT AS MOSTLY CLEAR SKIES WILL ALLOW TEMPS TO DROP BELOW GUID. TROF FCST TO DEEPEN IN AGAIN ACRS THE LAKES REGION OVER THE WEEKEND WITH SVL SPOKES OF VORTICITY TRACKING ACRS THE FCST AREA. ABOUT ENOUGH TO PRODUCE SCATTERED FLURRIES AND THAT IS ABOUT IT. SOME COLDER AIR FILTERING IN AT 850 MB BUT WE HAVE SEEN IT QUITE A BIT COLDER ACRS THE AREA IN THE PAST SVL DAYS. BUT WITH A FRESH SNOW COVER...STILL THINKING GUID IS TOO OPTIMISTIC SO WL CUT IT BACK A SEVERAL DEGREES. LONG TERM...SUNDAY THROUGH THURSDAY... WL USE A BLEND BETWEEN THE ECMWF AND GFS IN THE LONGER TERM WITH THE GREAT LAKES TROF FCST TO MOVE EAST OF THE AREA BY TUESDAY. STILL FEEL MEX GUID A BIT TOO AGRESSIVE WITH THE WARMING NEXT WEEK AS FLOW FLATTENS OUT SOME ACRS THE MIDWEST. THAT WILL BE TEMPORARY AS ADDL SHORTWAVE ENERGY IS FCST TO TRACK SE OUT OF SW CANADA BY NEXT WED AND POSSIBLY INFLUENCE A SRN STREAM WAVE. THAT MAY BRING PRECIP BACK INTO OUR NECK OF THE WOODS BY LATE NEXT WEEK...BUT TIMING OF THAT EVENT TOO MUCH IN DOUBT TO PUT IN GRIDS AT THIS TIME. && .ILX WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY IN EFFECT THROUGH 9 PM CST TODAY FOR KNOX...STARK... MARSHALL...FULTON...PEORIA...WOODFORD...TAZEWELL...MASON...MENARD SCHUYLER...CASS...SCOTT...MORGAN...SANGAMON AND LOGAN COUNTIES. SNOW ADVISORY IN EFFECT FROM 10 AM TO 9 PM CST TODAY FOR CHRISTIAN... SHELBY...MACON...MOULTRIE...COLES...CLARK...CUMBERLAND... EFFINGHAM...JASPER...CRAWFORD...CLAY...RICHLAND AND LAWRENCE COUNTIES. SNOW ADVISORY IN EFFECT FROM 10 AM TO MIDNIGHT CST TODAY FOR MCLEAN...DEWITT...PIATT...CHAMPAIGN...VERMILION...DOUGLAS AND EDGAR COUNTIES. && $$ SMITH il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 915 PM EST THU DEC 8 2005 .UPDATE... UPGRADE REMAINDER OF CWA TO HEAVY SNOW WARNING WITH 5-8 INCHES...MAYBE SPOT 9 INCHES IN SE CWA AS NNE-SSW MESOBANDING INDICATED KIND 88-D. 3H JETLET SAMPLED AT KILN/160 KT. FEATURE UNDERESTIMATED BY NAM12 AND RUC BY AROUND 30KTS. DEEP LAYER ASCENT ENHANCED IN REGION WHERE FAVORABLE 2-3 G/KG ON I285 SURFACE THROUGH FOR NEXT COUPLE OF HOURS. 30-35 DBZ WITH BANDS LIFTING INTO SE FA WILL ADD TO ALREADY GENERAL 4-6 INCHES. 7H LOW NOW INTO NORTH CENTRAL IL NEAR KPNT HAVE EXTENDED CAT SNOW POPS A FEW MORE HOURS WITH RAPID TAPER BY DAYBREAK. UPDATE... (810 PM) NORTHERN THIRD UPGRADED TO HEAVY SNOW WARNING. AMOUNTS AT LEAST IN NORTHWEST PART OF CWA IN 3-5 INCH RANGE ALREADY AND SNWFL RATES OF 1.0-2.0 INCHES PER HOUR TO CONTINUE THROUGH 04Z. BAND PIVOT POINT IN EXTREME NW INDIANA ATTM HIEGHTENING AMOUNTS THERE. TROWAL/I285 ISENT LIFT WITH 2-3G/KG TAP GENERATING MODERATE TO HEAVY BANDS DESPITE WEAK SURFACE REFLECTION THOUGH BEGINNING TO DEEPEN MORE ACROSS CENTRAL INDIANA WITH GREATER THAN 4MB/3HR FALLS INTO SOUTHERN CWA. DEFORMATION ZONE/7H TRACK SHOULD GIVE NORTHERN AREAS THE HIGHEST TOTALS AND HAVE UPPED TOTALS TO 6-9 WITH 4-7 IN REMAINDER OF ADVISORY AREA. && .PREV DISCUSSION... SHORT TERM... TONIGHT AND FRIDAY... LATEST KIWX RADAR...AND RECENT OBSERVER REPORTS CONFIRM...LEADING EDGE OF SNOW NOW MOVING INTO SW CWA. MAIN FCST PROBLEM WAS IF ANY UPGRADE TO ADVISORY NEEDED. WATER VAPOR LOOP SHOWING UPPER LOW MOVING ALONG IA/MO BORDER WITH PROFILER DATA INDICATING 130KT UPPER JET ROUNDING BASE OF THE TROUGH IN SOUTHERN MO. MODELS IN GOOD AGREEMENT WITH TRACK OF THIS SYSTEM TONIGHT. VERY FAVORABLE DYNAMICS COME IN TO PLACE OVER THE CWA THIS EVENING...MAIN LIMITING FACTOR WILL BE PROGRESSIVE NATURE OF THIS SYSTEM AND RESULTING DURATION OF SNOW EVENT. SNOW THAT IS CURRENTLY ENTERING CWA ASSOCIATED WITH 850MB WAA. BY 00Z...700MB LOW EXPECTING TO BE ENTERING WEST CENTRAL ILLINOIS PLACING OUR AREA IN FAVORABLE DEFORMATION ZONE FOR ANOTHER ROUND OF SNOW IN CENTRAL AND NORTHERN PORTIONS OF THE CWA. BOTH GFS AND NAM INDICATING AREAS OF K INDEX AROUND 15 THIS EVENING SO BRIEF PERIODS OF HEAVY SNOW POSSIBLE. CROSS SECTIONS OVER NORTHERN CWA ALSO INDICATING GOOD PLACEMENT OF OMEGA IN RELATION TO FAVORABLE TEMP RANGE FOR DENDRITIC SNOW GROWTH. HOWEVER...OVERALL PATTERN TO REMAIN PROGRESSIVE AS NEXT UPSTREAM SHORT WAVE ALREADY DROPPING DOWN INTO NORTHERN PLAINS SO RESULT SHOULD BE A STRONG BUT SHORT LIVED SNOW EVENT...SO CURRENT FCST OF GENERALLY 4-7 NORTH 3-6 INCHES SOUTHEAST SEEMS REASONABLE SO WILL OPT TO CONTINUE ADVISORY AND HOLD OFF ON UPGRADE TO WARNING. UPPER LOW EXPECTED TO TRACK RIGHT OVER THE CWA BY 06Z...THIS SHOULD ACT TO SHIFT BEST DYNAMICS TO OUR NORTH AND EAST AFTER MIDNIGHT. MAY SEE SOME ADDITIONAL LAKE ENHANCEMENT AS SYSTEM EXITS WITH 925MB LOW OVER SE LAKE MICHIGAN AT 06Z. QUICK TRANSITION TO LAKE EFFECT AS DECENT NORTHERLY FETCH DEVELOPS WITH INVERSION HEIGHTS AROUND 4KFT AND MODEST DELTA T AROUND 15. SHOULD BE SHORT LIVED HOWEVER AS FLOW BECOMES WEST/SOUTHWEST BY 18Z...SO NOT EXPECTING MUCH MORE THAN AN ADDITIONAL INCH OR SO IN THE LAKE EFFECT AREA. LONG TERM... ACTIVE PATTERN WITH BELOW NORMAL TEMPERATURES EXPECTED TO CONTINUE THROUGH MOST OF THE LONG TERM PERIOD. ON THE LARGE SCALE...SEVERAL STRONG SHORT WAVE TROUGHS SEEN IN WATER VAPOR UPSTREAM...RIDING OVER TOP OF WESTERN RIDGE. FIRST SHORT WAVE TO IMPACT LONG TERM PERIODS IS SEEN IN WATER VAPOR DIGGING INTO MONTANA AND WYOMING. 12Z MODELS IN GOOD AGREEMENT DIGGING THIS WAVE INTO THE OH AND TN VALLEY REGION BY SATURDAY. DESPITE VIGOROUS LOOK IN THE 500MB HEIGHT AND VORT FIELDS...MOISTURE ASSOCIATED WITH THIS FEATURE IS LACKING AND CURRENT TRACK WOULD PLACE IT TOO FAR SOUTH TO HAVE MUCH IMPACT ON OUR FORECAST AREA. NEXT SHORT WAVE TO HAVE MORE OF AN IMPACT AS IT APPEARS TO HAVE MORE MOISTURE ASSOCIATED WITH IT. THIS WAVE IS CURRENTLY TOPPING THE WESTERN RIDGE AND WILL QUICKLY FOLLOW FIRST WAVE...BRINGING A REINFORCEMENT OF COLD AIR AND HELPING CARVE OUT DEEP EASTERN CONUS TROUGH. NUMEROUS WEAKER SHORT WAVES WILL THEN MOVE THROUGH THIS LONG WAVE TROUGH WITH PLENTY OF MOISTURE IN PLACE FOR OFF AND ON SNOW SHOWERS. UNCERTAINTY THEN LIES IN THE DAY 6 THROUGH 8 TIME FRAME AS MODELS HAVING TROUBLE HANDLING WESTERN RIDGE AND CUTOFF LOW THAT UNDERCUTS IT AND THE PHASING OF ANOTHER SHORT WAVE COMING SOUTH OUT OF CANADA. MODELS TEND TO BE TOO PROGRESSIVE WITH NORTHERN STREAM IN SUCH CASES...AS THEY WERE LAST WEEK WITH TODAYS DEVELOPING SYSTEM. TEND TO FAVOR SOMETHING CLOSER TO 12Z GFS WHICH DIGS SHORT WAVE ENERGY FURTHER SOUTH INTO LOW LIFTING OUT OF SOUTHWEST. THIS WOULD RESULT IN A STRONGER AND SLOWER SOLUTION. HAVE OPTED FOR A CHANCE OF SNOW IN THE DAY 7 TIME FRAME BUT MUCH UNCERTAINTY WITH OVERALL PATTERN BY THIS TIME. IN THE DETAILS...HAVE KEPT SATURDAY DRY WITH THE VIGOROUS SHORT WAVE DUE TO ITS POSITION WELL SOUTH OF US AND LACKING MOISTURE. LIGHT SNOW AND SNOW SHOWERS SHOULD ACCOMPANY ARCTIC FRONT SAT NIGHT SUNDAY AS 100+ 300 MB JET DIVES SOUTHEAST AND PUTS THE AREA IN LEFT FRONT REGION. POSSIBLE LAKE EFFECT SNOW SUNDAY WITH NORTHWEST FLOW AND DELTA T VALUES IN UPPER TEENS. HAVE GONE WITH SOME ACCUMS IN FAVORED LAKE EFFECT AREAS AND HIGH CHANCE POPS. THE EMBEDDED SHORT WAVES AND LINGERING MOISTURE WILL KEEP SNOW SHOWERS IN FORECAST THROUGH MONDAY NIGHT BEFORE POSSIBLE RIDGING MOVES IN TUE. KEPT TUE AND WED DRY FOR NOW AS RIDING TRIES TO HOLD AHEAD OF DIGGING UPSTREAM WAVE. ADDED POPS TO DAY 7 FOR THE POSSIBILITY OF THIS UPSTREAM WAVE MOVING IN. LOWERED TEMPERATURES MOST PERIODS...ESPECIALLY SUNDAY INTO TUE WITH LARGE SCALE AMPLIFIED TROUGH OVER AREA. ANY CLEARING DURING NIGHTIME HOURS WILL LEAD TO MORE SINGLE DIGIT OR COLDER LOWS GIVEN EXPECTED SNOW COVER. TOO DIFFICULT TO NAIL DOWN RIGHT NOW WITH THE SHORT WAVE ENERGY AND TIMING OF ANY CLEARING AND DECOUPLING. BEST CHANCE MAY BE FRIDAY NIGHT BETWEEN WAVES WHEN MODELS CLEAR OUT RH MOST LEVELS AHEAD OF UPSTREAM SHORT WAVE. && .AVIATION... IMPENDING WINTER STORM MAIN CONCERN FOR THIS TAF ISSUANCE. NEXT SEVERAL HOURS WILL REMAIN DRY AS INITIAL ISENTROPIC UPGLIDE GOES INTO SATURATION OF DRY AIR MASS. IMPRESSIVE UPPER LEVEL DYNAMICS IN CONJUNCTION WITH INCREASED MOISTURE RETURN WILL RESULT IN SNOW RAPIDLY OVERSPREADING THE AREA LATER THIS AFTERNOON. CONDITIONS WILL QUICKLY DETERIORATE INTO LIFR CONDITIONS THIS EVENING AS MODERATE TO HEAVY SNOW OVERSPREADS THE TAF SITES. RELATIVELY FAST MOVEMENT OF SYSTEM SHOULD ALLOW CONDITIONS TO IMPROVE SOMEWHAT AFTER 06Z FRIDAY. HOWEVER...BRIEF WINDOW OF NORTHWEST FLOW LAKE EFFECT WILL RESULT IN CONTINUATION OF IFR CONDITIONS ACROSS KSBN THROUGH 15Z. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR INZ017-INZ018. HEAVY SNOW WARNING UNTIL 4 AM EST /3 AM CST/ FRIDAY FOR INZ003- INZ004-INZ005-INZ006-INZ007-INZ008-INZ009-INZ012-INZ014- INZ016. HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR INZ013-INZ015- INZ020-INZ022-INZ023-INZ024-INZ025-INZ026-INZ027-INZ032- INZ033-INZ034. MI...HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR OHZ004-OHZ005- OHZ015-OHZ016-OHZ024-OHZ025. HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR OHZ001-OHZ002. LM...NONE. && $$ SHORT TERM...MURPHY LONG TERM....14 AVIATION...14 in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 142 PM CST THU DEC 8 2005 .DISCUSSION... DAYS 1-2... FOR THIS FORECAST...THE MAIN DECISION POINTS ARE TEMPERATURES. LOOKS LIKE THERE WILL BE VERY LITTLE IN THE WAY OF CLOUDS THROUGH 36 HOURS...WITH CIRRUS SLIGHTLY ON THE INCREASE FROM 36-48 HOURS. EXPECT THE WINDS WILL STAY UP OUT OF THE SOUTHWEST TONIGHT IN THE 7- 12 KT RANGE. THIS WILL KEEP TEMPERATURES FROM FALLING A PURE DIURNAL RATES. DO NOT THINK THE SNOW COVER IS MUCH OF A FACTOR... EXCEPT IN THE NORTHEASTERN CWA WHERE COLD AIR HAS KEPT MUCH OF THE 1- 2 INCH BLANKET TODAY. VISIBLE SATELLITE LOOPS SHOW MELTING GOING ON ACROSS ABOUT THE SOUTHERN 1/2 OF CWA TODAY...ESPECIALLY NOTABLE IN THE RIVER VALLEYS. AS FOR TEMPS...TONIGHT WILL STICK PRETTY MUCH WITH WHAT THE PREVIOUS SHIFT HAD...JUST A TAD COLDER IN THE NORTHEAST. BASED ON WARMING OF THE WINTER SUN TODAY...BUMPED MAX TEMPS FOR FRIDAY A DEGREE OR TWO ACROSS THE BOARD. IT COULD GET NEAR 40 IN THE EHA AND LBL AREAS... BUT FOR CONSISTENCY SAKE HAVE NOT WENT THAT HIGH. WEST TO NORTHWEST DOWNSLOPE FLOW FRIDAY NIGHT SHOULD ALLOW MIN TEMPS TO MODERATE TO THE TEENS. EVEN THOUGH HIGH CLOUDS WILL ROLL IN ON SATURDAY... STILL EXPECT MID 40S SOUTHWEST AND LOWER 40S NORTH. MODELS INITIALIZE VERY WELL WITH EACH OTHER THIS MORNING AT 12Z. THE NGM AND GFS WERE NOT COLD ENOUGH AT THE SURFACE...AS GCK WAS -10 AND TRB -14 AND MODELS STARTED THEM BOTH OFF AROUND -2. LIKE THE COLDER ETA AND RUC. DAYS 3-7... MODELS CONTINUE TO DIVERGE ON SOLUTIONS WITH TIMING OF S/W TROFS EMBEDDED IN THE NORTHWEST FLOW NEXT WEEK. ANY CASE STILL LOOKS LIKE A FAIRLY DRY WEATHER PATTERN AND AS FOR TEMPS IT LOOKS LIKE THEY WILL WARM SOME AHEAD OF EACH WAVE...FOLLOWED BY A COOL DOWN. NO REAL COLD PUSH EVIDENT YET. BASED ON TIMING ISSUES HAVE OPTED NOT TO GET TOO DETAILED WITH THE WARMUP AND COOL DOWN WITH EACH OF THESE WEAK WAVES BUT THE EXCEPTION IS LATE WEEK WHERE ALL MODELS ARE IN DECENT AGREEMENT WITH THIS 5H TROF. WITH ALL MODELS CONTINUE TO SUPPORT SOMETHING CROSSING THE PLAINS MID WEEK AM UNABLE TO COMPLETELY RULE OUT PCPN CHANCES CURRENTLY IN THE GRIDS FOR WED. SIMILARLY BASED ON THE DISCREPANCIES CONFIDENCE IS NOT HIGH ENOUGH TO ADD PCPN CHANCES THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 5 36 17 43 / 0 0 0 0 GCK 4 37 16 44 / 0 0 0 0 EHA 7 38 18 46 / 0 0 0 0 LBL 5 38 17 46 / 0 0 0 0 HYS 5 31 18 41 / 0 0 0 0 P28 6 37 19 44 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN12/18 ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PADUCAH KY 945 AM CST THU DEC 8 2005 .UPDATED DISCUSSION FOR THIS AFTERNOON... WILL BE REALIGNING THE WINTER STORM WARNING AND WINTER WEATHER ADVISORIES TO BETTER REFLECT CURRENT RADAR AND TEMPERATURE TRENDS. WARNING WILL BE EXTENDED WEST ACROSS THE WABASH RIVER INTO SOUTHEAST ILLINOIS...WHILE WARNING IN THE SOUTHERN PENNYRILE REGION OF KY WILL BE DOWNGRADED TO AN ADVISORY. 12Z PROFILER AND RUC DATA INDICATE LOW LEVEL WINDS REMAIN SOUTHERLY ACROSS MOST OF THE REGION...RESULTING IN DECENT WARM ADVECTION. PRECIP TYPE IS MAINLY RAIN OR FREEZING RAIN ALONG AND SE OF PAH TO EVV LINE. EVEN FAR NORTHWESTERN COUNTIES HAVE REPORTED A MIX WITH ICE AND SLEET...SO WILL CHANGE SNOW ADVISORIES TO WINTER WEATHER ADVISORIES THERE. STORM TOTAL SNOWFALL AMOUNTS MAY BE A LITTLE LOWER THAN PREVIOUSLY EXPECTED DUE TO THE MIX...HOWEVER ICING WILL BE AN ISSUE IN MOST AREAS. WHERE SURFACE TEMPS ARE NEAR FREEZING AND ROADS ARE STILL IN FAIRLY GOOD SHAPE...WILL DOWNGRADE WARNING TO ADVISORY. WILL BASE TIMING OF CHANGEOVER TO SNOW MAINLY ON RUC MODEL 925 AND 850 MB WET BULB ZERO TEMPS. && .PREVIOUS DISCUSSION... FIRST WINTER STORM OF THE SEASON LURKING JUST TO OUR WEST AND SOUTH EARLY THIS MORNING. REGIONAL MOSAIC SHOWED A LARGE AREA OF PRECIPITATION MOVG STEADILY NE ACROSS CENTRAL ARKANSAS. SNOW WAS ACROSS A GOOD PART OF CENTRAL AND WESTERN MISSOURI AS WELL. GFS AND NAM ARE IN GENERAL AGREEMENT WITH THE LARGE SCALE FEATURES. MODELS SHIFT SUBSTANTIAL FORCING AND MOISTURE ACROSS THE FA THROUGH THE MORNING HOURS...SHIFTING TO OUR EASTERN COUNTIES BY EARLY AFTERNOON. PRECIP TYPE DEFINITELY A CHALLENGE...ESPECIALLY ACROSS WESTERN KENTUCKY. BUFKIT FORECAST SOUNDINGS OFF THE NAM AND GFS BOTH SHOW ALL PRECIP TYPES POSSIBLE ACROSS WEST KENTUCKY...WITH GENERALLY SNOW ALONG AND NORTHWEST OF THE OHIO AND WABASH RIVERS. BOTH MODELS SUGGEST BEST QPF OVER WEST KENTUCKY AS WELL...WHICH LINES UP WELL WITH HPC GUIDANCE. WILL HAVE R/ZR/IP/S FOR COUNTIES BORDERING TN. WILL KEEP MORE SLEET AND SNOW WITH A CHANCE OF A LITTLE ZR NORTH OF THERE TOWARD THE OHIO RIVER. WITH THAT SAID...MADE ADJUSTMENTS TO CURRENT WARNINGS AND ADVISORIES. SEE THE WWA SECTION BELOW FOR DETAILS. IN TERMS OF AMOUNTS...GFS AND NAM SUGGEST GREATEST ACCUMULATION OF SNOW MAY BE OVER EVV TRI STATE...WITH AN AXIS EXTENDING SW CLOSE TO THE OHIO RIVER...AND ACCUMULATIONS ANYWHERE FROM 2 TO 4 INCHES. JUST SOUTH OF THIS AXIS...WHERE MORE OF A MIX IS POSSIBLE AMOUNTS SHOULD BE A LITTLE LOWER. AMOUNTS SHOULD BE A LITTLE LOWER AS WELL FROM PTNS OF SE MISSOURI INTO SW ILLINOIS. OVERALL...STILL A RELATIVELY LOW CONFIDENCE CALL AT THIS POINT. EXPECT A RAPID DEPARTURE OF THE PRECIPITATION...FIRST OVER SE MISSOURI THIS AFTERNOON...ENDING ACROSS THE REMAINDER OF THE REGION BY EARLY EVENING. WITH THE MID LEVEL TROF HANGING BACK JUST A TAD...THE PRECIP MAY END AS A PERIOD OF LIGHT DRIZZLE/FREEZING DRIZZLE. DRY WX IS FORECAST TO RETURN FOR FRIDAY THROUGH THE WEEKEND. THE MID TROPOSPHERIC FLOW WILL REMAIN FAIRLY AMPLIFIED...WITH A BROAD TROF OVER THE EASTERN U.S. AND RIDGING OVER THE WEST. TEMPERATURES SHOULD MODERATE SLIGHTLY INTO THE WEEKEND...BUT REMAIN AT OR BELOW NORMAL. NO CHANGES MADE TO THE LONG RANGE PORTION OF THE FORECAST. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY TODAY FOR MUCH OF WESTERN KENTUCKY SOUTH AND WEST OF MADISONVILLE. WINTER STORM WARNING TODAY AND EARLY THIS EVENING FOR PENNYRILE REGION FROM MADISONVILLE NORTH AND EAST. MO...WINTER WEATHER ADVISORY FOR ALL COUNTIES TODAY. IL...WINTER STORM WARNING FOR EDWARDS...WABASH...WHITE AND GALLATIN COUNTIES THROUGH EARLY THIS EVENING. WINTER WEATHER ADVISORY REST OF SOUTHERN ILLINOIS TODAY. IN...WINTER STORM WARNING THROUGH EARLY THIS EVENING. && $$ UPDATE...MY/KES PREVIOUS...CN ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 325 PM EST THU DEC 8 2005 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE POTENTIAL FOR SNOW TONIGHT. WATER VAPOR IMAGERY AND RUC/NAM DEPICTS A MID LEVEL LOW OVER SOUTHEAST IOWA. A WEAK SHORTWAVE SWEEPING AROUND THIS LOW IS OVER LOWER MICHIGAN...AND ANOTHER OVER SOUTHERN ILLINOIS. SURFACE ANALYSIS SHOWING A LOW OVER INDIANA BORDERED BY A RIDGE OVER THE CENTRAL PLAINS AND ANOTHER OTHER MID ATLANTIC STATES. ANOTHER LOW IS OVER HUDSON BAY WITH A COLD FRONT DRAPED THROUGH CENTRAL CANADA. INSTABILITY ASSOCIATED WITH THE SHORTWAVE AND MOISTURE ACCOMPANYING THE SURFACE LOW OVER THE WESTERN OHIO RIVER VALLEY CONTINUE TO GENERATE SCATTERED SNOW SHOWERS AND FOG OVER THE MIDDLE MISSISSIPPI RIVER VALLEY AND WESTERN OHIO RIVER VALLEY. THE LOW OVER INDIANA AND ASSOCIATED SHORTWAVES WILL PUSH INTO WESTERN NEW YORK STATE TONIGHT. THE SURFACE LOW WILL LIKE PUSH INTO THE LOWER GREAT LAKES DRAGGING THE COLD FRONT INTO THE MID ATLANTIC STATES. THE CANADIAN COLD FRONT WILL DROP INTO CENTRAL ONTARIO. THE HIGH OVER THE CENTRAL PLAIN WILL MIGRATE INTO THE MIDDLE MISSISSIPPI RIVER VALLEY OVERNIGHT. AS THE SURFACE LOW MOVES EAST THE SURFACE WINDS WILL BECOME MORE OUT OF THE WEST. LAKE-850MB DELTA-T'S WILL DECREASE TO AROUND 14C OVER THE CENTRAL LAKE SUPERIOR. THIS WILL FEED SCATTERED LAKE EFFECT SNOWS OVER THE KEWEENAW PENINSULA AND EASTERN LAKE SUPERIOR TONIGHT. THE LOWEST INVERSION WILL LOWER TO 925MB OVERNIGHT...WHICH WILL LIMIT SNOW GROWTH AND THE AMOUNT OF SNOW PRODUCED. SNOW SHOULD CONTINUE BUT LIGHT AND SCATTERED. THE MID LEVEL LOW OVER THE LOWER GREAT LAKES WILL CONTINUE ITS EASTWARD TREK ON FRIDAY. IN ITS WAKE A WEAK SHORTWAVE WILL SLIDE INTO THE MID MISSISSIPPI RIVER VALLEY...WHILE ANOTHER WEAK SHORTWAVE PUSHES INTO THE ARROWHEAD OF MINNESOTA FOLLOWED BY A LITTLE DEEPER SHORTWAVE OVER THE SOUTHERN MANITOBA. THE CENTRAL PLAINS RIDGE WILL RELOCATE OVER THE LOWER MISSISSIPPI RIVER VALLEY ON FRIDAY. A SURFACE LOW WILL SLIDE SOUTHEAST ALONG THE FRONT FROM NORTHWEST CANADA AND INTO THE LAKE WINNIPEG AREA. A STRONG WESTERLY FLOW WILL CONTINUE AHEAD OF THE FRONT. A WEAK SURFACE TROUGH WILL BE GENERATED OVER THE CENTRAL DAKOTAS. DELTA-T'S WILL BE BE AROUND 11C OVER THE WESTERN LAKE SUPERIOR. THE BASE OF THE LOWEST INVERSION WILL BE AROUND 900MB WILL SOME FAIRLY STEEP LAPSE RATES BELOW THIS LEVEL. SURFACE-900MB RH CONTINUE TO BE AROUND 90 PERCENT OVER THE NORTHERN LAKE SUPERIOR. THUS SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE OVER THE KEWEENAW PENINSULA AND EASTERN LAKE SUPERIOR THROUGHOUT THE DAY ON FRIDAY. THE SHORTWAVE OVER MANITOBA WILL SWEEP INTO CENTRAL LAKE SUPERIOR AND THE WESTERN U.P. FRIDAY NIGHT. THE SURFACE LOW WILL SHIFT TO JUST NORTH OF CENTRAL LAKE SUPERIOR WHILE THE SURFACE TROUGH MOVES INTO WESTERN U.P. AS THESE DO MOVE INTO THE FORECAST AREA...EXPECT TO SEE SNOWS SPREADING FROM WEST TO EAST ACROSS THE FORECAST AREA. THE SHORTWAVE WILL SWEEEP ACROSS THE REST OF THE FORECAST AREA ON SATURDAY. THE SURFACE LOW WILL MOVE INTO EAST CENTRAL ONTARIO WHILE DRAWING THE SURFACE TROUGH INTO THE EASTERN U.P. INSTABILITY ASSOCIATED THIS TROUGH AND LOW LEVEL MOISTURE WILL REMAIN AROUND 90 PERCENT OVER THE AREA. THUS WILL KEEP SNOW GOING THROUGH SATURDAY. ANOTHER SHORTWAVE WILL SWEEP THROUGH THE FORECAST AREA ON SATURDAY NIGHT. AN 850MB THERMAL TROUGH WILL SLIDE OVER ONTARIO AND INCREASE THE DELTA-T'S OVER LAKE SUPERIOR TO AROUND 20C BY 12Z SUNDAY. AS THE SURFACE WINDS WILL INCREASE AND SHIFT TO THE NORTHWEST OVER LAKE SUPERIOR...LAKE EFFECT SNOWS SHOULD DEVELOP SATURDAY NIGHT AND CONTINUE INTO SUNDAY. THE MID LEVEL LOW OVER JAMES BAY WILL EDGE INTO WEST CENTRAL QUEBEC SUNDAY NIGHT. A WEAK SHORTWAVE SWEEPING THROUGH THE BASE OF THIS LOW WILL PASS OVER THE FORECAST AREA. THE SURFACE LOW WILL MOVE INTO ARROWHEAD OF MINNESOTA...WHILE AN ACCOMPANYING SURFACE TROUGH STALLS OUT OVER THE CENTRAL U.P. MEAN RH IN A SURFACE TO 500MB LAYER WILL BE > 90 PERCENT ACROSS THE AREA. THE SURFACE-850MB DELTA-T'S WILL BE 16C TO 20C OVER LAKE SUPERIOR. THE GREATEST DELTA-T'S WILL BE OVER THE EAST PART OF THE LAKE. THUS CONDITIONS LOOK FAVOR LAKE EFFECT SNOW SHOWERS TO CONTINUE WITH VERY LITTLE CHANGE THROUGH TUESDAY. THE MID LEVEL LOW WILL MOVE INTO CENTRAL QUEBEC WITH THE WEAK SHORTWAVE MOVING INTO CENTRAL U.P. AND LAKE SUPERIOR. THE MID LEVEL LOW WILL SLIDE A LITTLE FURTHER EAST DRAWING THE WEAK SHORTWAVES TO THE EAST OF THE FORECAST AREA TUESDAY NIGHT AS A RIDGE PUSHES INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE SURFACE LOW WILL SLIDE INTO SOUTHEAST MINNESOTA. AN ASSOCIATED WARM FRONT WILL EXTEND NORTHEAST ACROSS NORTHERN LAKE MICHIGAN. OVERRUNNING OF THIS FRONT WILL CONTINUE ENOUGH INSTABILITY TO KEEP SNOW GOING OVER THE AERA. THE SURFACE LOW WILL THEN MOVE INTO NORTHERN LAKE MICHIGAN WEDNESDAY NIGHT. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1211 PM EST THU DEC 8 2005 .AVIATION... VFR CONDITIONS WILL RAPIDLY DETERIORATE FROM SOUTH TO NORTH BY 00Z. A STRONG LOW PRESSURE SYSTEM DEVELOPING OVER THE MISSISSIPPI VALLEY WILL TRACK RAPIDLY NORTHEAST TO WESTERN LAKE ERIE BY 06Z. AHEAD OF THIS LOW MVFR CIGS AND VSBYS IN SNOW WILL MOVE INTO THE DTW AREA BY 23Z AND THE MBS AREA AROUND 02Z. STORM DYNAMICS WILL INCREASE DURING THE OVERNIGHT HOURS...BRINGING IFR AND LIFR CONDITIONS ACROSS THE REGION BY 03-06Z. THE LOW WILL TRACK RAPIDLY EAST OF THE REGION AFTER 12Z...WITH MVFR CONDITION RETURNING TO THE REGION AFTER 13Z...AND SNOWFALL IS EXPECTED TO END AROUND 15Z WITH CIGS RISING TO 020-025. WINDS AREA EXPECTED TO REMAIN AT 12KT OR LESS THROUGH THE PERIOD DUE TO THE PROXIMITY OF THE LOW...HOWEVER WIND DIRECTIONS WILL BE SHIFTING RAPIDLY BETWEEN 04-09Z AS THE LOW PRESSURE SYSTEM TRACKS JUST SOUTH OF DTW. && .UPDATE... EARLY WINTER STORM TAKING SHAPE ACROSS THE CENTRAL MISSISSIPPI VALLEY. SUBSTANTIAL MOISTURE TRANSPORT FROM THE GULF OF MEXICO IS MANIFESTING ITSELF IN WIDESPREAD PRECIP DEVELOPMENT ACROSS INDIANA AND ILLINOIS THIS MORNING. THE DEFORMATION AXIS IS BECOMING MUCH MORE DEFINED ACROSS THE ST LOUIS AREA...WHERE HEAVY SNOW IS OCCURRING. 12Z SUITE OF SOLUTIONS CONTINUE TO SUPPORT A QUICK BUT INTENSE PERIOD OF SNOW ACROSS SOUTHERN LOWER MICHIGAN DURING THE EVENING AND OVERNIGHT HOURS. THE COMBINATION OF STRONG MID TO UPPER LEVEL DYNAMICS (INCLUDING VERY PRONOUNCED LEFT EXIT JET DYNAMICS) AND THE RAPID INTENSIFICATION OF A MID-LEVEL DEFORMATION AXIS (TROWAL) PRODUCING DEEP LAYER LIFT (ON THE ORDER OF 15-20 UB/S IN THE ETA)...WEAK STABILITY ALOFT INTRODUCING THE PROSPECTS OF UPRIGHT CONVECTION WITHIN THE TROWAL AXIS...AND FAVORABLE SNOW GROWTH MICROPHYSICS (BEST ASCENT OCCURRING IN THE -13 TO -18C RANGE) SUPPORTING INCREASED SNOW EFFICIENCY...WILL GENERATE INTENSE SNOWFALL RATES DURING THE LATE EVENING AND POST MIDNIGHT TIMEFRAME. SNOWFALL TOTALS OF 5 TO 8 INCHES ARE EXPECTED...AND COULD BE LOCALLY HIGHER IF THE ELEVATED INSTABILITY IS COMPLETELY REALIZED. THE LIMITING FACTOR FOR THIS EVENT WILL BE ITS SHORT DURATION...WITH ESSENTIALLY 6 HOURS OF GOOD ACCUMULATING SNOW EXPECTED. SNOWFALL TOTALS WILL DECREASE TO THE NORTH...WHERE THE FORCING AND OTHER EXTENUATING FACTORS WILL BE MORE LIMITED. && PREV DISCUSSION... (ISSUED 319 AM EST THU DEC 8 2005) DISCUSSION... THE FIRST SNOWSTORM FOR MUCH OF SOUTHEAST MICHIGAN ARRIVES TONIGHT! RELATIVELY COMPACT UPPER LEVEL STORM SYSTEM OVER THE CENTRAL CONUS APPEARS TO BE MAKING A BEELINE FOR SOUTHEAST MICHIGAN...PLACING THE REGION IN THE WELL DEVELOPED COMMA HEAD TONIGHT. WATER VAPOR IMAGERY IS CONCERNING...AS THERE IS A PINEAPPLE CONNECTION WITH THE MOISTURE STREAMING INTO THE GULF COAST STATES. 850 MB FLOW OVER THE LOWER MISSISSIPPI VALLEY HAS BACKED TO THE SOUTH-SOUTHEAST ALREADY. 00Z PRECIPITABLE WATER ANALYSIS HAS SHOWN A QUICK RETURN OF MOISTURE OVER EASTERN TEXAS/OKLAHOMA/WESTERN ARKANSAS. EVEN WITH LIMITED MOISTURE ENTRAINED THUS FAR...THIS SYSTEM HAS PRODUCED 8 INCHES OF SNOW IN AND AROUND THE KANSAS CITY METRO AREA. MEANWHILE...A STRONG AREA OF HIGH PRESSURE (1040 MB) RESIDES OVER THE OHIO VALLEY/LOWER GREAT LAKES. THIS ARCTIC AIRMASS IN PLACE WILL PROVIDE A NICE COLD DOME FOR THE TROWAL TO WORK OVER. TRYING TO PIN DOWN THE HEAVIEST SNOW IS NOW ONE THE BIGGEST FORECAST DIFFICULTIES. MODEL CONSENSUS DOES SHOW THE SURFACE LOW TRACK MOVING THROUGH NW OHIO AND THEN NORTHEAST THROUGH LAKE ERIE (INDICATED BY THE NAM YESTERDAY). NAM CONTINUES TO INDICATE A DEEPER LOW...WITH THE RUC13 THE DEEPEST AND FARTHEST NORTH (THROUGH SOUTHEAST MICHIGAN). THAT WOULD PLACE THE HEAVIEST SNOWFALL ACROSS THE NORTHERN THIRD OF THE CWA. DON'T REALLY SEE THE SURFACE LOW TRACKING THAT FAR NORTH INTO THE COLD AIR ESTABLISHED OVER THE AREA. PREFERENCE OUT OF HPC IS WITH THE GFS...AND THAT SEEMS REASONABLE TO ME. IN ANY EVENT...700 MB LIFT FORECASTED BY THE GFS AND NAM ARE BOTH VERY IMPRESSIVE (10 TO 20 -UBAR/S) OVER MUCH OF SOUTHEAST MICHIGAN...RIGHT IN THE IDEAL SNOW GROWTH REGION (AROUND -14 C PER GFS). THE PROBLEM WITH THIS EVENT IS THAT INTENSE LIFT WILL BE SHORT-LIVED...3 TO 4 HOUR WINDOW. WITH HIGH SNOW TO LIQUID RATIOS (20-15 TO 1)...CAN EASILY BE LOOKING AT 1.5 INCH/HR RATES WHICH PLACES TOTALS RIGHT AT THE 12 HOUR WARNING CRITERIA. VERY TOUGH CALL ON WHAT TO DO...WITH 4 TO 7 INCH AMOUNTS EXPECTED. THE COBB TECHNIQUE BASED OFF THE GFS GIVES DETROIT 5.7 INCHES AND THE FLINT AREA 5.1 INCHES. 12 HR QPF FORECAST FROM GFS WAS 0.32 INCHES OVER THE KANSAS CITY AREA (18-6Z)...KMCI CAME IN WITH 0.35 INCHES. GFS FORECASTS A 12 HR QPF BULLSEYE OF 0.34 INCHES MOVING INTO WESTERN PART OF THE CWA TONIGHT. GFS 290 K SURFACE INDICATES SPECIFIC HUMIDITY VALUES OF 3 G/KG TRYING TO SNEAK INTO THE CWA...ORIGINATING FROM THE SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY. WITH COLLABORATION FROM SURROUNDING OFFICES...WILL GO AHEAD AND ISSUE A WATCH FROM I-69 SOUTH. ALTHOUGH THE HIGHEST QPF LOOKS TO BE ACROSS THE SOUTH...SNOW TO LIQUID RATIOS WILL BE MAXIMIZED FARTHER NORTH...AND THUS EXPECTED THE HEAVIEST TOTALS TO FALL ALONG OR JUST SOUTH OF THE I-69 CORRIDOR. NORTHEAST FLOW OFF OF LAKE HURON COULD EVEN ENHANCE AMOUNTS AROUND PORT HURON...WITH UP TO 8 INCHES POSSIBLE...AS THAT AREA ALSO CORRESPONDS TO THE BEST LIFT ADVERTISED BY THE GFS. NOT A WHOLE LOT OF TIME SPENT ON THE REMAINDER OF THE FORECAST. THE LONGWAVE PATTERN LOOKS TO BE THE SAME...WITH DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION/EASTERN CONUS LATE IN THE WEEKEND INTO EARLY NEXT WEEK...SUPPORTING A CHANCE OF SNOW SHOWERS AND SLIGHTLY BELOW NORMAL TEMPERATURES. WITH 00Z GFS/EUROPEAN INDICATING THE TROUGH AXIS OVER THE CENTRAL GREAT LAKES SUNDAY MORNING (COLD FRONT)...DID RAISE POPS TO 40 PERCENT SATURDAY NIGHT INTO SUNDAY. ALSO LOWERED MAXES ON SUNDAY TO AROUND 30 DEGREES. OTHERWISE NO CHANGES TO THE REST OF THE FORECAST. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...HEAVY SNOW WARNING...MIZ055-MIZ060-MIZ061-MIZ062-MIZ063-MIZ068- MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-MIZ083...6 PM THURSDAY TO 6 AM FRIDAY. SNOW ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054...6 PM THURSDAY TO 6 AM FRIDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...MANN AVIATION.....GSS YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 647 AM EST THU DEC 8 2005 .AVIATION... VERY COLD MORNING TEMPS ARE RESULTING IN SOME MVFR VISIBILITY OBSTRUCTIONS DUE TO ICE CRYSTALS. THIS WILL BE SHORT LIVED AND WILL BE GONE SHORTLY AFTER SUNRISE. MVFR CEILING IN LAKE STRATUS WILL LAST A LITTLE LONGER AROUND THE DETROIT TERMINALS BUT IT TOO WILL MOVE NORTH AND DISSIPATE DURING THE MORNING. LATER THIS MORNING CONDITIONS WILL BE VFR AT ALL SITES AND THEN DETERIORATE RAPIDLY EARLY THIS EVENING AS SNOW MOVES INTO THE AREA. VISIBILITY AND CEILING WILL DROP QUICKLY THROUGH MVFR AND IFR AFTER 00Z THIS EVENING, AND INTO LIFR AT ALL TERMINALS BY MIDNIGHT. THE SNOW WILL SPREAD FROM SW TO NE OVER THE AREA AND RESULT IN SLIGHTLY LATER TIMING OF ONSET AROUND MBS. THE LOW PRESSURE CENTER WILL TRACK FROM NEAR INDIANAPOLIS AT SUNSET THIS EVENING, TO NEAR TOLEDO BY MIDNIGHT, AND THEN TOWARD THE WEST END OF LAKE ONTARIO BY FRIDAY MORNING. THE SNOW WILL DIMINISH AND CONDITIONS WILL IMPROVE TO MVFR BY 12Z FRIDAY MORNING. && .PREV DISCUSSION... (ISSUED 319 AM EST THU DEC 8 2005) DISCUSSION... THE FIRST SNOWSTORM FOR MUCH OF SOUTHEAST MICHIGAN ARRIVES TONIGHT! RELATIVELY COMPACT UPPER LEVEL STORM SYSTEM OVER THE CENTRAL CONUS APPEARS TO BE MAKING A BEELINE FOR SOUTHEAST MICHIGAN...PLACING THE REGION IN THE WELL DEVELOPED COMMA HEAD TONIGHT. WATER VAPOR IMAGERY IS CONCERNING...AS THERE IS A PINEAPPLE CONNECTION WITH THE MOISTURE STREAMING INTO THE GULF COAST STATES. 850 MB FLOW OVER THE LOWER MISSISSIPPI VALLEY HAS BACKED TO THE SOUTH-SOUTHEAST ALREADY. 00Z PRECIPITABLE WATER ANALYSIS HAS SHOWN A QUICK RETURN OF MOISTURE OVER EASTERN TEXAS/OKLAHOMA/WESTERN ARKANSAS. EVEN WITH LIMITED MOISTURE ENTRAINED THUS FAR...THIS SYSTEM HAS PRODUCED 8 INCHES OF SNOW IN AND AROUND THE KANSAS CITY METRO AREA. MEANWHILE...A STRONG AREA OF HIGH PRESSURE (1040 MB) RESIDES OVER THE OHIO VALLEY/LOWER GREAT LAKES. THIS ARCTIC AIRMASS IN PLACE WILL PROVIDE A NICE COLD DOME FOR THE TROWAL TO WORK OVER. TRYING TO PIN DOWN THE HEAVIEST SNOW IS NOW ONE THE BIGGEST FORECAST DIFFICULTIES. MODEL CONSENSUS DOES SHOW THE SURFACE LOW TRACK MOVING THROUGH NW OHIO AND THEN NORTHEAST THROUGH LAKE ERIE (INDICATED BY THE NAM YESTERDAY). NAM CONTINUES TO INDICATE A DEEPER LOW...WITH THE RUC13 THE DEEPEST AND FARTHEST NORTH (THROUGH SOUTHEAST MICHIGAN). THAT WOULD PLACE THE HEAVIEST SNOWFALL ACROSS THE NORTHERN THIRD OF THE CWA. DON'T REALLY SEE THE SURFACE LOW TRACKING THAT FAR NORTH INTO THE COLD AIR ESTABLISHED OVER THE AREA. PREFERENCE OUT OF HPC IS WITH THE GFS...AND THAT SEEMS REASONABLE TO ME. IN ANY EVENT...700 MB LIFT FORECASTED BY THE GFS AND NAM ARE BOTH VERY IMPRESSIVE (10 TO 20 -UBAR/S) OVER MUCH OF SOUTHEAST MICHIGAN...RIGHT IN THE IDEAL SNOW GROWTH REGION (AROUND -14 C PER GFS). THE PROBLEM WITH THIS EVENT IS THAT INTENSE LIFT WILL BE SHORT-LIVED...3 TO 4 HOUR WINDOW. WITH HIGH SNOW TO LIQUID RATIOS (20-15 TO 1)...CAN EASILY BE LOOKING AT 1.5 INCH/HR RATES WHICH PLACES TOTALS RIGHT AT THE 12 HOUR WARNING CRITERIA. VERY TOUGH CALL ON WHAT TO DO...WITH 4 TO 7 INCH AMOUNTS EXPECTED. THE COBB TECHNIQUE BASED OFF THE GFS GIVES DETROIT 5.7 INCHES AND THE FLINT AREA 5.1 INCHES. 12 HR QPF FORECAST FROM GFS WAS 0.32 INCHES OVER THE KANSAS CITY AREA (18-6Z)...KMCI CAME IN WITH 0.35 INCHES. GFS FORECASTS A 12 HR QPF BULLSEYE OF 0.34 INCHES MOVING INTO WESTERN PART OF THE CWA TONIGHT. GFS 290 K SURFACE INDICATES SPECIFIC HUMIDITY VALUES OF 3 G/KG TRYING TO SNEAK INTO THE CWA...ORIGINATING FROM THE SOUTHERN PLAINS/LOWER MISSISSIPPI VALLEY. WITH COLLABORATION FROM SURROUNDING OFFICES...WILL GO AHEAD AND ISSUE A WATCH FROM I-69 SOUTH. ALTHOUGH THE HIGHEST QPF LOOKS TO BE ACROSS THE SOUTH...SNOW TO LIQUID RATIOS WILL BE MAXIMIZED FARTHER NORTH...AND THUS EXPECTED THE HEAVIEST TOTALS TO FALL ALONG OR JUST SOUTH OF THE I-69 CORRIDOR. NORTHEAST FLOW OFF OF LAKE HURON COULD EVEN ENHANCE AMOUNTS AROUND PORT HURON...WITH UP TO 8 INCHES POSSIBLE...AS THAT AREA ALSO CORRESPONDS TO THE BEST LIFT ADVERTISED BY THE GFS. NOT A WHOLE LOT OF TIME SPENT ON THE REMAINDER OF THE FORECAST. THE LONGWAVE PATTERN LOOKS TO BE THE SAME...WITH DEEP UPPER LEVEL TROUGH OVER THE GREAT LAKES REGION/EASTERN CONUS LATE IN THE WEEKEND INTO EARLY NEXT WEEK...SUPPORTING A CHANCE OF SNOW SHOWERS AND SLIGHTLY BELOW NORMAL TEMPERATURES. WITH 00Z GFS/EUROPEAN INDICATING THE TROUGH AXIS OVER THE CENTRAL GREAT LAKES SUNDAY MORNING (COLD FRONT)...DID RAISE POPS TO 40 PERCENT SATURDAY NIGHT INTO SUNDAY. ALSO LOWERED MAXES ON SUNDAY TO AROUND 30 DEGREES. OTHERWISE NO CHANGES TO THE REST OF THE FORECAST. AVIATION... QUIET FOR MOST OF THE FORECAST...BUT THINGS GO DOWN HILL QUICKLY LATE THURSDAY AFTERNOON...ON THROUGH THE EVENING AS VERY DYNAMIC UPPER LOW LIFTS INTO THE REGION FROM THE CENTRAL PLAINS. DEEPENING SURFACE LOW WILL TRACK JUST SOUTHEAST OF THE REGION. CONFIGURATION OF THIS SYSTEM WILL BRING A PERIOD OF MODERATE/OCCASIONALLY HEAVY SNOW TO THE AREA...ESPECIALLY DTW/DET (AND FOR THE MOST PART FNT). WILL END VFR CONDITIONS IN THE 22Z-00Z TIMEFRAME...AND BRING ON MVFR AND IFR WITH RAPIDLY LOWERING CEILINGS AND VISIBILITIES IN THE SNOW. THIS WILL CARRY THROUGH TO 06Z BEFORE BEST LIFT BEGINS TO SPREAD EAST OF THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...WINTER STORM WATCH...MIZ055-MIZ060-MIZ061-MIZ062-MIZ063-MIZ068- MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-MIZ083...6 PM THURSDAY TO 6 AM FRIDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...BT SHORT TERM...SF LONG TERM....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1100 AM CST THU DEC 8 2005 .DISCUSSION... UPDATE WILL BE COMING OUT SHORTLY TO CANCEL SNOW ADVISORY ALONG AND WEST OF A MT. STERLING TO TROY MO TO UNION LINE...MAINLY BASED ON RADAR TRENDS. THE CANCELLED AREAS HAVE OR WILL SHORTLY END THEIR ACCUMULATING SNOW. SNOWFALL AMOUNTS GENERALLY RANGE 2 TO 3 INCHES OVER CNTRL MO WITH 3 TO 5 INCHES IN NE MO/W CNTRL IL. SPOTTER JUST CALLED FROM EWING IN LEWIS COUNTY MO WITH A TOTAL NEAR 7 INCHES. FARTHER SOUTHEST...MESOSCALE BANDING REMAINS IMPRESSIVE ON RADAR WITH MODERATE TO HEAVY SNOW REPORTS COMMON OVER THE PAST TWO HOURS AT THE ST. LOUIS METRO AREA OB SITES. LATEST RUC STILL SHOWS THE DECENT COMBINATION OF LARGE SCALE UPWARD MOTION AND MID LEVEL FRONTOGENESIS ASSOCIATED WITH STORM SYSTEM TRANSLATING EWD INTO IL THROUGH 21Z. AREAS ALONG THE MS RIVER WILL BEGIN TO DIMINISH EARLY THIS AFTERNOON WITH S CNTRL IL LOCATIONS CONTINUING MOST OF THE AFTERNOON. SNOWFALL AMOUNTS WILL TOP OUT AROUND 2-3 INCHES IN THE METRO AREA WITH UP TO 4 INCHES OVER NEAR VANDALIA AND SALEM IL. && .LSX WATCHES/WARNINGS/ADVISORIES... MO...SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR JEFFERSON- ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-STE. GENEVIEVE- IL...SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BOND IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL- MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-RANDOLPH IL- ST. CLAIR IL-WASHINGTON IL. && $$ BRITT mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 913 AM CST THU DEC 8 2005 .DISCUSSION... SNOWFALL REPORTS FROM CNTRL AND NERN MO AND W CNTRL IL CAME IN WITH 2 TO 3 INCHES THIS MORNING. THE SNOW IS BEGINNING TO DIMINISH WEST OF OF A FULTON TO QUINCY LINE...BUT AREAS TO THE EAST SHOULD STILL SEE ANOTHER 1 TO 2 INCHES OF SNOW. FARTHER SOUTHEAST...RADAR TRENDS HAVE SHOWN THAT SSW-NNE MESOSCALE BANDS HAVE DEVELOPED OVER THE LAST TWO HOURS OVER EASTERN MISSOURI AND SOUTHWEST ILLINOIS. VIH IS ON THE TAIL END OF ONE OF THESE BANDS AND IS STILL REPORTING 1/2SM SN. EVEN THOUGH THE SNOW WAS LATE TO START THIS MORNING IN THE STL METRO AREA BECAUSE OF THE LOW LEVEL DRY AIR...THE REPORTING STATIONS ARE CURRENTLY AOB 1SM VISIBILITY. RADAR IS INDICATING THERE MAY BE A FEW POCKETS OF +SN OUT THERE...AND THE LATEST RUC RUN INDICATES THAT THE COMBINATION OF SYNOPTIC AND MESOSCALE FORCING SHOLD CONTINUE WELL INTO THE AFTERNOON. BASED ON THIS...WILL CONTINUE THE 2 TO 4 INCH FORECAST FROM AROUND THE STL METRO OVER TOWARD SOUTH CENTRAL IL. && .LSX WATCHES/WARNINGS/ADVISORIES... MO...SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR FRANKLIN- JEFFERSON-LINCOLN-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-STE. GENEVIEVE-WARREN. SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR AUDRAIN-BOONE- CALLAWAY-COLE-GASCONADE-KNOX-LEWIS-MARION-MONITEAU-MONROE- MONTGOMERY-OSAGE-PIKE-RALLS-SHELBY. IL...SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BOND IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL- MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-RANDOLPH IL- ST. CLAIR IL-WASHINGTON IL. SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR ADAMS IL-BROWN IL-PIKE IL. && $$ BRITT mo AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BUFFALO NY 940 PM EST THU DEC 8 2005 .UPDATE... LEADING EDGE OF LARGE AREA OF SNOW CURRENTLY ENTERING EXTREME SOUTHWEST NEW YORK. 01Z SURFACE ANALYSIS SHOWED AN ELONGATED AREA OF LOW PRESSURE FROM NORTHWEST INDIANA SOUTHEAST INTO EASTERN KENTUCKY. HEAVIEST SNOWS CURRENTLY IN AREA OF STRONG MID LEVEL FRONTOGENETIC FORCING AND ISENTROPIC ASCENT JUST NORTH OF WEAK SURFACE REFLECTION OVER FAR NORTHERN INDIANA. LATEST RUC AND NAM SUGGESTING SURFACE REFLECTION WILL DEEPEN AND TAKE AN EAST NORTHEAST TRACK ACROSS LAKE ERIE OVERNIGHT. BASED ON CURRENT 3 HOUR PRESSURE FALLS...THINK MODEL TRACK IS REASONABLE...THEREFORE KEEPING PRIMARY MID LEVEL FRONTOGENETIC FORCING/DEFORMATION ZONE JUST TO THE NORTHWEST OF THE AREA. IN ADDITION...SHARP DRY SLOT SEEN ON WATER VAPOR LOOP CUTTING INTO SOUTHWEST AND CENTRAL OHIO TAKING AIM ON WESTERN NEW YORK. THIS IS ALSO SUGGESTED BY BOTH THE RUC AND NAM...WHICH MODESTLY LOWER SNOWFALL AMOUNTS ACROSS THE AREA. AT THIS POINT...WILL MAINTAIN LOW END ADVISORY FOR THE AREA...BY EDGING SNOWFALL AMOUNTS ACROSS THE AREA DOWN TO 2 TO 4 INCHES OVERNIGHT. THE POTENTIAL CONTINUES TO EXIST FOR SOME LINGERING SNOWFALL AMOUNTS FRIDAY MORNING...ESPECIALLY FOR EASTERN SECTIONS AS SYSTEM PULLS AWAY FROM THE AREA. && .SHORT TERM (TONIGHT THROUGH SUNDAY)... COLD HIGH PRESSURE OVER THE REGION WILL SHIFT TO THE EAST TONIGHT...ALLOWING LOW PRESSURE FORMING OVER THE UPPER OHIO VALLEY TO MOVE ACROSS THE REGION TONIGHT. THIS LOW PRESSURE SYSTEM WILL BRING A WIDESPREAD AND STEADY SNOW TO THE ENTIRE FORECAST AREA OVERNIGHT AND EARLY FRIDAY. BOTH NAM AND GFS HAVE BEEN EDGING THE SURFACE LOW A LITTLE FARTHER TO THE NORTHWEST WITH EACH RUN...WHICH WOULD PLACE SOUTHWESTERN NY IN THE REGION OF STRONGER LOW LEVEL FORCING AND WAA SNOW PATTERN. WE EXPECT A GENERAL SNOWFALL OF 4 TO 6 INCHES OVER THE ENTIRE FORECAST AREA BUT THERE MAY BE GREATER AMOUNTS TO 8 INCHES ACROSS THE WESTERN SOUTHERN TIER AND OVER THE SOUTHERN TUG HILL PLATEAU. HAVE GONE WITH A BLEND OF NAM AND GFS...BOTH ARE SIMILAR IN TRACK AND TIMING OF THE SURFACE LOW...BUT TENDED SNOW COVERAGE CLOSER TO GENERAL 4 TO 6 INCH RANGE OFFERED BY GFS RATHER THAN THE WIDER RANGE OF SNOW AMOUNTS FROM NAM. THERE WILL BE ENOUGH TO WARRANT SNOW ADVISORY FOR THE ENTIRE F/A TONIGHT AND EARLY FRIDAY. FLAT RIDGING FOLLOWING THE LOW ON SATURDAY WILL BE MARGINALLY COLD ENOUGH FOR ONLY A FEW LAKE EFFECT FLURRIES OR LIGHT SNOW SHOWERS...IF AT ALL. LOW PRESSURE PASSING NORTH OF THE GREAT LAKES WILL SWING A COLD FRONT ACROSS THE REGION ON SUNDAY WITH ANOTHER ROUND OF LIGHT SNOW AND MINOR ACCUMULATIONS. && .LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)... THE WINTRY PATTERN WILL CONTINUE THROUGH THIS PERIOD AS A LONG WAVE UPPER TROUGH PERSISTS ACROSS EASTERN CANADA AND THE GREAT LAKES REGION. 850 MILLIBAR TEMPERATURES ARE FORECAST TO AVERAGE AROUND MINUS 15C THROUGH AT LEAST WEDNESDAY THEN JUST A LITTLE WARMER THURSDAY AS A RIDGE EDGES IN FROM THE WEST. NO MAJOR STORMS ARE FORESEEN AT THIS TIME BUT THE NORTHWEST FLOW ACROSS THE LAKES WILL LIKELY PRODUCE SOME SCATTERED LAKE EFFECT SNOWS. && .AVIATION... VFR CONDITIONS WILL ABRUPTLY DROP TO IFR IN SNOW LATE THIS EVENING ACROSS THE SOUTHWESTERN PART OF NEW YORK AND THEN SPREAD NORTHEAST QUICKLY OVERNIGHT REACHING WATERTOWN AROUND 2 AM. THE SNOW IS EXPECTED TO TAPER OFF QUICKLY BY MIDDAY OVER WESTERN AREAS AND LATER IN THE DAY EAST BUT CEILINGS WILL REMAIN MVFR. && .MARINE... SOUTHWEST WINDS WILL PICK UP SIGNIFICANTLY LATE TONIGHT AND FOR AWHILE FRIDAY WITH SMALL CRAFT ADVISORY CRITERIA EXPECTED BY MID TO LATE MORNING ON THE EAST ENDS OF BOTH LAKES ERIE AND ONTARIO. && .BUF WATCHES/WARNINGS/ADVISORIES... .NY...SNOW ADVISORY ALL ZONES THURS NT INTO FRIDAY. $$ UPDATE...TMA SHORT TERM...HIBBERT LONG TERM/AVIATION...SAGE ny AREA FORECAST DISCUSSION...CORRECTION. NATIONAL WEATHER SERVICE RALEIGH NC 955 PM EST THU DEC 8 2005 ...THE ADVISORY ENDING TIME WILL BE CHANGED TO RUN THROUGH 800 AM OR 13Z/09 DECEMBER... NO OTHER CHANGES TO THE ADVISORIES ALREADY IN EFFECT. QPF SHOULD BE MORE LIMITED THAN PREVIOUS FORECASTS... .SYNOPSIS... STRONG SURFACE HIGH CENTERED OVER ATLANTIC CITY NJ (1037 MB) WAS OF ARCTIC ORIGIN BUT WAS SHIFTING EAST AND OFFSHORE THIS EVENING. THE HIGH LEFT RESIDUAL COLD DRY AIR OVER THE PIEDMONT DAMMING REGION... WHICH WILL LEAD TO A QUICK IN-SITU DAMMING EVENT OVERNIGHT. THE 00Z/09 DECEMBER GREENSBORO RAOB PARTIAL THICKNESS VALUES WERE 1304/1553 UP FROM THE 1293/1544 VALUES AT 18Z/08... INDICATING SOME FREEZING RAIN POTENTIAL FOR THE FAR NW-N PIEDMONT. && .SHORT TERM (REST OF TONIGHT)... ...PROBLEMS OF THE NIGHT INCLUDE: THE AMOUNT OF PRECIPITATION (CURRENT THINKING IS THAT THE QPF MAY ONLY RANGE BETWEEN 0.25 AND 0.40)... DOWN FROM THE EARLIER PROJECTIONS)... AND HOW MUCH OF THIS WILL FREEZE AND ACCRUE ON EXPOSED OBJECTS OVER THE NW PIEDMONT DAMMING REGION?... ...HIGH CONFIDENCE IN P-TYPE NOW... (RAIN... EXCEPT FREEZING RAIN OCCASIONALLY MIXED WITH RAIN OVER THE NW PIEDMONT)... FIRST THE PRECIP COVERAGE AND QPF... (MEDIUM CONFIDENCE BASED ON RECENT TRENDS). PRECIPITATION HAS BEEN VERY SLOW TO DEVELOP OVER THE MAIN AREA OF CONCERN (OUR NW TIER OF PIEDMONT COUNTIES) THIS EVENING. CURRENT OBSERVATIONS AND RADAR INDICATE A LOWERING OVERCAST AT GSO AND INT BUT NO PRECIPITATION AS OF 900 PM. UPSTREAM... THERE REMAINS A DISCONNECT FROM THE SOUTHERN BRANCH PRECIP EXTENDING FROM FLORIDA UP THE SC COAST... AND THE PRECIP ASSOCIATED WITH THE UPPER LEVEL SYSTEM OVER THE TN VALLEY AND OHIO VALLEY. A DEFINITE MINIMUM CONTINUED FROM ATLANTA TO GSP TO CLT AND GSO. THE MODELS SEEMED TO HAVE OVER FORECAST THE AMOUNT OF ISENTROPIC LIFT OVER THIS REGION... 35-40 KNOTS OF H8 WIND OBSERVED AT 00Z/09 AS OPPOSED TO 50-55 KNOTS MODEL FORECASTS. THUS... EVEN THOUGH THE RADAR INDICATED PRECIPITATION "FILLING IN" OVER THIS REGION SINCE 800 PM... IT WAS STILL RATHER UNORGANIZED. THIS LEADS ME TO BELIEVE THAT THE EVENTUAL PRECIP (QPF)... WILL END UP ONLY ABOUT 1/2 TO 3/4 OF OUR ORIGINAL FORECAST. THIS WOULD BRING A QPF OF 0.25 TO 0.50 STORM TOTAL BEFORE IT ENDS AROUND DAYBREAK. AS FOR P-TYPE... HIGH CONFIDENCE HERE. REASONING... SEVERAL LARGE PATCHES OF PRECIPITATION HAVE MOVED NE ACROSS THE MOUNTAINS AND NORTHERN FOOTHILLS SINCE 600 PM. PRECIPITATION BEGAN AS VERY LIGHT SNOW IN SURRY COUNTY (40 NW OF WINSTON-SALEM) AROUND 700 PM... BUT QUICKLY BECAME LIGHT FREEZING RAIN. THE TEMPERATURE AT THE ONSET OF PRECIP AT DOBSON WAS 32... AND THE 900 PM READING WAS 29... INDICATING THE AFFECTS OF EVAPORATIVE COOLING IN THE HEART OF THE CURRENT DEVELOPING INSITU-DAMMING EVENT. HAVING THE PRECIPITATION IN THE FORM OF FREEZING RAIN OVER THE NORTHERN FOOTHILLS INDICATES THE WARMING ALOFT AS PREVIOUSLY FORECAST WAS WELL UNDERWAY. THIS STRONGLY SUPPORTS THE ONGOING FORECAST P-TYPE OF FREEZING RAIN FOR THE FAR NW PIEDMONT (STILL COULD BE MIXED WITH A LITTLE NUISANCE SLEET AT THE ONSET)... AND RAIN ELSEWHERE. IN THE NEARBY PIEDMONT TRIAD CITIES OF WINSTON-SALEM AND GREENSBORO... THE SURFACE TEMPS HAVE BEEN STEADY AT 33-34 DEGREES WITH DEW POINT READINGS IN THE LOWER 20S... INDICATING THAT WET BULB TEMPERATURES WERE STILL HOLDING IN THE 28 TO 31 RANGE. HAD SIGNIFICANT PRECIPITATION MOVED IN EARLIER... THERE WOULD HAVE BEEN SOME GLAZING ON EXPOSED SURFACES ALREADY. 00Z/09 DECEMBER GREENSBORO RAOB INDICATED SIGNIFICANT WARMING (7-9 DEGREES F) AT 3-4K FEET WITH AN INCREASING SSE JET AT THAT LEVEL. UPSTREAM AT ATLANTA... THE TEMP AT 5K FEET HAD SURGED TO 50 DEGREES WITH A SW WIND AT 40 KNOTS. THIS CORRESPONDS WELL WITH THE WARMER TEMPS NOTED OVER THE HIGHER SOUTHWEST MOUNTAINS OF NC (SW OF AVL) WHERE READINGS WERE IN THE 40S. LIGHT FREEZING RAIN CONTINUED TO DEVELOP EAST OF THE MOUNTAINS AND INTO THE PIEDMONT DAMMING REGION FROM HICKORY TO STATESVILLE AND MOCKSVILLE. FREEZING RAIN IS STILL EXPECTED TO DEVELOP OVER THE CENTRAL NC ADVISORY AREA OF THE NW PIEDMONT AROUND OR NEAR 1200 AM. HOWEVER... THE IN-SITU DAMMING WILL THAT DEVELOPS WILL LIKELY BECOME VERY SHALLOW... AS THE COLUMN WARMS FROM THE TOP DOWN LATER TONIGHT. THIS WILL LIMIT ACCRUAL OF GLAZE. ANOTHER FACTOR THAT WILL GREATLY LIMIT ACCRUAL NEAR THE GROUND LEVEL WILL BE THE PAVEMENT TEMPS THAT WERE RUNNING IN THE MID 40S AT THE GSO AIRPORT AT MID EVENING. GROUND TEMPS WERE IN THE UPPER 30S AND LOWER 40S... INDICATING THAT IT WOULD TAKE MODERATE TO HEAVY SNOW OR SLEET TO CREATE SIGNIFICANT ACCUMULATIONS ON MAIN ROADS. WE WILL CONTINUE THE WINTER WEATHER ADVISORY AND WILL STRESS THAT FREEZING RAIN ACCRUAL SHOULD BE LIMITED TO ELEVATED SURFACES SUCH AS TREE BRANCHES... GRASS BLADES... TRAILINGS... VEHICLE WINDSHIELD... SIDEWALKS... AND POSSIBLY SOME BRIDGES AND OVERPASSES. GLAZING MAY ACCRUE TO BETWEEN A TENTH OR LOCALLY TWO TENTHS BEFORE ENDING. BASED ON THE CURRENT AND PROJECTED WET BULB TEMPS... THERE MAY BE A LITTLE LIGHT GLAZING OBSERVED AS FAR EAST AND SOUTH AS PERSON... NORTHERN DURHAM.. NORTHWEST ORANGE AND SOUTHEAST RANDOLPH COUNTIES.\ RAIN IS EXPECTED ELSEWHERE AS WET BULB TEMPS ARE ON THE WAY UP FROM 32-35 RIGHT NOW. PRECIP ENDS QUICKLY LATER TONIGHT FROM WEST TO EAST WITH DRY COLD WEATHER TO RETURN FRIDAY. NO OTHER CHANGES NEEDED. BADGETT && .PREVIOUS DISCUSSION... (ISSUED 245 PM EST THU DEC 8 2005) SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... TONIGHT THROUGH FRIDAY: QUESTION MARKS STILL REMAIN REGARDING THIS PRECIP EVENT. AS EXPECTED THE PARENT HIGH TO OUR NORTH HAS BROKEN FREE FROM THE MORE ARCTIC MIDWEST HIGH... ALTHOUGH OUR HIGH IS STRONGER THAN PREVIOUSLY PROGGED AND THE DEWPOINTS ARE RUNNING A FEW DEGREES BELOW EARLIER FORECASTS... WHICH BRINGS ABOUT CONCERN WHEN ONE TRIES TO TAKE THE MODELS AT FACE VALUE. THE HIGH HAS SLID EAST TODAY AND SHOULD CONTINUE TO BE TRANSITORY AND WEAKEN A BIT INTO THE 1030S TONIGHT AS IT SHIFTS OFFSHORE... HOWEVER ITS STRENGTH IS STILL DECENT AND WHEN THE PRECIP STARTS AND LIKELY INSTIGATES AN AGEOSTROPHIC SURFACE WIND ADJUSTMENT TO A MORE UNIFORM NNE DIRECTION... THERE MAY BE AN HOUR OR TWO OF DRY AIR ADVECTION AND COUPLED WITH A LITTLE EVAPORATIVE COOLING IN THE LOW LEVELS... JUST ENOUGH TO BUMP LOW LEVEL THICKNESSES SLIGHTLY LOWER THAN FORECAST. THE 18Z GSO SOUNDING ARRIVED WITH LOW LEVEL THICKNESSES 5-9 METERS COLDER THAN MODEL FORECASTS. FINALLY... EVEN MODEL PROGS OF SURFACE WET BULB TEMPS ARE RUNNING COOLER BY A COUPLE OF DEGREES IN THE LATEST RUNS... THE RUC INCLUDED. IN SUMMARY... GIVEN THE STRONGER DRIER HIGH AND COOLER OBSERVED THERMAL PROFILE ALONG WITH MODEL PROGS TRENDING TO A COOLER SURFACE WET BULB... HAVE DECIDED TO EXPAND THE ADVISORY TO GUILFORD... DAVIDSON... RANDOLPH... AND ALAMANCE COUNTIES. A BIG ISSUE IS THE ARRIVAL OF PRECIP... WHICH LOOKS TO BE DELAYED BY A FEW HOURS AND WHICH SHOULD KEEP ICE ACCRUAL LIGHT BEFORE THE MASSIVE WARM AIR ADVECTION ENSUES TOWARD MIDNIGHT... AS 850 MB WINDS ACCELERATE UP TO 50-60 KTS. THIS STRONG WARMING ALOFT SHOULD ALSO ARRIVE IN MUCH OF THE NORTHEAST PIEDMONT EARLY ENOUGH SO THAT WHEN THE PRECIP ARRIVES THERE... IT SHOULD BE ALL RAIN... THUS DID NOT EXPAND THE ADVISORY ACROSS THE VA BORDER COUNTIES OF THE NE PIEDMONT AT THIS TIME. IF ANY BIT OF ZR DOES OCCUR... IT WOULD MOST LIKELY BE NORTH OF THE I-85 CORRIDOR... NORTH OF THE TRIANGLE. ANOTHER LIMITING FACTOR MAY BE THE PAVEMENT TEMPS WHICH ARE REPORTED TO BE IN THE 40S IN THE WINSTON-SALEM AREA... ALTHOUGH WE WILL NEED TO WATCH THESE VERY CAREFULLY DURING THIS EVENING. ELEVATED SURFACES ARE LIKELY TO BE MUCH COOLER HOWEVER. TEMPS TONIGHT SHOULD BE CLOSE TO THE CURRENT WET BULBS... AROUND 29 TO 38. WILL KEEP THE CURRENT TREND OF PRECIP MOVING OUT OF THE CENTRAL AND EASTERN CWA IN THE MORNING. PREFER THE COOLER MAV GUIDANCE HIGHS WITH SKIES CLEARING AND A BLUSTERY NW WIND. FRIDAY NIGHT THROUGH SATURDAY NIGHT: WITH A PORTION OF THE SURFACE HIGH PARKED OVERHEAD FRIDAY NIGHT AND WINDS DROPPING DOWN TO CALM... EXPECT CHILLY LOWS OF 19-27. LAST NIGHT'S LOWS BENEATH THIS AIR MASS WERE BELOW 0F SO WOULDN'T BE SURPRISED TO SEE QUITE A FEW TEENS. A DAMPENING WAVE ZIPS NORTHEASTWARD OVER THE AREA SATURDAY BUT HAS NO MOISTURE TO WORK WITH AND SHOULD BRING JUST A FEW CLOUDS AT MOST. WINDS THEN BECOME SOUTHWEST THROUGH THE COLUMN BUT THE SURFACE AIR MASS SHOULD ONLY BE ABLE TO MODIFY NOMINALLY... AND HIGH TEMPS SHOULD BE CLOSER TO NORMAL SATURDAY... ABOUT 48-53. -GIH LONG TERM (SUNDAY THROUGH THURSDAY)... A RATHER STRONG MID LEVEL VORT AXIS SWINGS THROUGH SUNDAY... THEN FOR SUNDAY NIGHT ONWARD... CONFIDENCE IS FAIRLY HIGH IN THE PERSISTENCE OF A MEAN TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD... ALTHOUGH CONSIDERABLE RUN-TO-RUN VARIATIONS IN THE GFS AND ECMWF MODELS AND THEIR LACK OF AGREEMENT WITH EACH OTHER BRING ABOUT MUCH LESS CONFIDENCE IN THE DETAILS WITHIN THIS FLOW REGIME. THE MORE CONSISTENT CANADIAN MODEL SEEMS TO BE AS GOOD A SOLUTION AS ANY... KEEPING THE TROUGH IN PLACE WITH RIDGING HOLDING IN THE WESTERN US AND PASSAGE OF VORT MAXIMA THROUGH NC INTO THE TROUGH BASE EVERY 2 DAYS OR SO. EXPECT LIMITED MOISTURE AVAILABILITY WITH SUCH A PATTERN... AND BARRING ANY PARTICULARLY VIGOROUS WAVES... THE PERIOD SHOULD REMAIN DRY WITH SOME CLOUDS FROM TIME TO TIME FROM EITHER A LITTLE MOISTURE TRAPPED BENEATH AN INVERSION ALOFT OR OROGRAPHIC ENHANCEMENT OF HIGHER CLOUDS WITH A DEEP AND SPEEDY W TO NW FLOW UP THROUGH THE COLUMN. TEMPS ROUGHLY A CATEGORY BELOW NORMAL EACH DAY. -GIH AVIATION... MID CLOUDINESS WILL THICKEN AND LOWER AS THIS AFTERNOON PROGRESSES. RAIN SHOULD DEVELOP FROM THE SOUTH AND WEST EARLY THIS EVENING. PRECIPITATION WILL TAKE THE FORM OF SLEET OR FREEZING RAIN FOR A FEW HOURS EARLY TONIGHT...MAINLY AT KINT AND KGSO. VISIBILITIES WILL DECREASE TO MVFR/IFR IN THE 00-06Z TIME FRAME AND SHOULD HOVER AROUND 1 MILE FROM 06Z THROUGH SUNRISE. CEILINGS WILL ALSO LOWER TO MVFR 00-04Z...THEN IFR OR LIFR 10-14Z WITH RAPID IMPROVEMENT WEST TO EAST FRI MORNING AS THE SURFACE LOW MOVES UP THE MID ATLANTIC COAST. -RFG && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FOR NCZ021>023-038-039 UNTIL 8 AM FRIDAY. && $$ SYNOPSIS... SHORT TERM...BADGETT/LOCKLEAR/REU nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 955 PM EST THU DEC 8 2005 ...NO CHANGES IN THE ADVISORIES ALREADY IN EFFECT. HOWEVER... QPF SHOULD BE MORE LIMITED THAN PREVIOUS FORECASTS... .SYNOPSIS... STRONG SURFACE HIGH CENTERED OVER ATLANTIC CITY NJ (1037 MB) WAS OF ARCTIC ORIGIN BUT WAS SHIFTING EAST AND OFFSHORE THIS EVENING. THE HIGH LEFT RESIDUAL COLD DRY AIR OVER THE PIEDMONT DAMMING REGION... WHICH WILL LEAD TO A QUICK IN-SITU DAMMING EVENT OVERNIGHT. THE 00Z/09 DECEMBER GREENSBORO RAOB PARTIAL THICKNESS VALUES WERE 1304/1553 UP FROM THE 1293/1544 VALUES AT 18Z/08... INDICATING SOME FREEZING RAIN POTENTIAL FOR THE FAR NW-N PIEDMONT. && .SHORT TERM (REST OF TONIGHT)... ...PROBLEMS OF THE NIGHT INCLUDE: THE AMOUNT OF PRECIPITATION (CURRENT THINKING IS THAT THE QPF MAY ONLY RANGE BETWEEN 0.25 AND 0.40)... DOWN FROM THE EARLIER PROJECTIONS)... AND HOW MUCH OF THIS WILL FREEZE AND ACCRUE ON EXPOSED OBJECTS OVER THE NW PIEDMONT DAMMING REGION?... .SHORT TERM DISCUSSION... ...HIGH CONFIDENCE IN P-TYPE NOW... (RAIN... EXCEPT FREEZING RAIN OCCASIONALLY MIXED WITH RAIN OVER THE NW PIEDMONT)... FIRST THE PRECIP COVERAGE AND QPF... (MEDIUM CONFIDENCE BASED ON RECENT TRENDS). PRECIPITATION HAS BEEN VERY SLOW TO DEVELOP OVER THE MAIN AREA OF CONCERN (OUR NW TIER OF PIEDMONT COUNTIES) THIS EVENING. CURRENT OBSERVATIONS AND RADAR INDICATE A LOWERING OVERCAST AT GSO AND INT BUT NO PRECIPITATION AS OF 900 PM. UPSTREAM... THERE REMAINS A DISCONNECT FROM THE SOUTHERN BRANCH PRECIP EXTENDING FROM FLORIDA UP THE SC COAST... AND THE PRECIP ASSOCIATED WITH THE UPPER LEVEL SYSTEM OVER THE TN VALLEY AND OHIO VALLEY. A DEFINITE MINIMUM CONTINUED FROM ATLANTA TO GSP TO CLT AND GSO. THE MODELS SEEMED TO HAVE OVER FORECAST THE AMOUNT OF ISENTROPIC LIFT OVER THIS REGION... 35-40 KNOTS OF H8 WIND OBSERVED AT 00Z/09 AS OPPOSED TO 50-55 KNOTS MODEL FORECASTS. THUS... EVEN THOUGH THE RADAR INDICATED PRECIPITATION "FILLING IN" OVER THIS REGION SINCE 800 PM... IT WAS STILL RATHER UNORGANIZED. THIS LEADS ME TO BELIEVE THAT THE EVENTUAL PRECIP (QPF)... WILL END UP ONLY ABOUT 1/2 TO 3/4 OF OUR ORIGINAL FORECAST. THIS WOULD BRING A QPF OF 0.25 TO 0.50 STORM TOTAL BEFORE IT ENDS AROUND DAYBREAK. AS FOR P-TYPE... HIGH CONFIDENCE HERE. REASONING... SEVERAL LARGE PATCHES OF PRECIPITATION HAVE MOVED NE ACROSS THE MOUNTAINS AND NORTHERN FOOTHILLS SINCE 600 PM. PRECIPITATION BEGAN AS VERY LIGHT SNOW IN SURRY COUNTY (40 NW OF WINSTON-SALEM) AROUND 700 PM... BUT QUICKLY BECAME LIGHT FREEZING RAIN. THE TEMPERATURE AT THE ONSET OF PRECIP AT DOBSON WAS 32... AND THE 900 PM READING WAS 29... INDICATING THE AFFECTS OF EVAPORATIVE COOLING IN THE HEART OF THE CURRENT DEVELOPING INSITU-DAMMING EVENT. HAVING THE PRECIPITATION IN THE FORM OF FREEZING RAIN OVER THE NORTHERN FOOTHILLS INDICATES THE WARMING ALOFT AS PREVIOUSLY FORECAST WAS WELL UNDERWAY. THIS STRONGLY SUPPORTS THE ONGOING FORECAST P-TYPE OF FREEZING RAIN FOR THE FAR NW PIEDMONT (STILL COULD BE MIXED WITH A LITTLE NUISANCE SLEET AT THE ONSET)... AND RAIN ELSEWHERE. IN THE NEARBY PIEDMONT TRIAD CITIES OF WINSTON-SALEM AND GREENSBORO... THE SURFACE TEMPS HAVE BEEN STEADY AT 33-34 DEGREES WITH DEW POINT READINGS IN THE LOWER 20S... INDICATING THAT WET BULB TEMPERATURES WERE STILL HOLDING IN THE 28 TO 31 RANGE. HAD SIGNIFICANT PRECIPITATION MOVED IN EARLIER... THERE WOULD HAVE BEEN SOME GLAZING ON EXPOSED SURFACES ALREADY. 00Z/09 DECEMBER GREENSBORO RAOB INDICATED SIGNIFICANT WARMING (7-9 DEGREES F) AT 3-4K FEET WITH AN INCREASING SSE JET AT THAT LEVEL. UPSTREAM AT ATLANTA... THE TEMP AT 5K FEET HAD SURGED TO 50 DEGREES WITH A SW WIND AT 40 KNOTS. THIS CORRESPONDS WELL WITH THE WARMER TEMPS NOTED OVER THE HIGHER SOUTHWEST MOUNTAINS OF NC (SW OF AVL) WHERE READINGS WERE IN THE 40S. LIGHT FREEZING RAIN CONTINUED TO DEVELOP EAST OF THE MOUNTAINS AND INTO THE PIEDMONT DAMMING REGION FROM HICKORY TO STATESVILLE AND MOCKSVILLE. FREEZING RAIN IS STILL EXPECTED TO DEVELOP OVER THE CENTRAL NC ADVISORY AREA OF THE NW PIEDMONT AROUND OR NEAR 1200 AM. HOWEVER... THE IN-SITU DAMMING WILL THAT DEVELOPS WILL LIKELY BECOME VERY SHALLOW... AS THE COLUMN WARMS FROM THE TOP DOWN LATER TONIGHT. THIS WILL LIMIT ACCRUAL OF GLAZE. ANOTHER FACTOR THAT WILL GREATLY LIMIT ACCRUAL NEAR THE GROUND LEVEL WILL BE THE PAVEMENT TEMPS THAT WERE RUNNING IN THE MID 40S AT THE GSO AIRPORT AT MID EVENING. GROUND TEMPS WERE IN THE UPPER 30S AND LOWER 40S... INDICATING THAT IT WOULD TAKE MODERATE TO HEAVY SNOW OR SLEET TO CREATE SIGNIFICANT ACCUMULATIONS ON MAIN ROADS. WE WILL CONTINUE THE WINTER WEATHER ADVISORY AND WILL STRESS THAT FREEZING RAIN ACCRUAL SHOULD BE LIMITED TO ELEVATED SURFACES SUCH AS TREE BRANCHES... GRASS BLADES... TRAILINGS... VEHICLE WINDSHIELD... SIDEWALKS... AND POSSIBLY SOME BRIDGES AND OVERPASSES. GLAZING MAY ACCRUE TO BETWEEN A TENTH OR LOCALLY TWO TENTHS BEFORE ENDING. BASED ON THE CURRENT AND PROJECTED WET BULB TEMPS... THERE MAY BE A LITTLE LIGHT GLAZING OBSERVED AS FAR EAST AND SOUTH AS PERSON... NORTHERN DURHAM.. NORTHWEST ORANGE AND SOUTHEAST RANDOLPH COUNTIES.\ RAIN IS EXPECTED ELSEWHERE AS WET BULB TEMPS ARE ON THE WAY UP FROM 32-35 RIGHT NOW. PRECIP ENDS QUICKLY LATER TONIGHT FROM WEST TO EAST WITH DRY COLD WEATHER TO RETURN FRIDAY. NO OTHER CHANGES NEEDED. BADGETT && .PREVIOUS DISCUSSION... (ISSUED 245 PM EST THU DEC 8 2005) SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... TONIGHT THROUGH FRIDAY: QUESTION MARKS STILL REMAIN REGARDING THIS PRECIP EVENT. AS EXPECTED THE PARENT HIGH TO OUR NORTH HAS BROKEN FREE FROM THE MORE ARCTIC MIDWEST HIGH... ALTHOUGH OUR HIGH IS STRONGER THAN PREVIOUSLY PROGGED AND THE DEWPOINTS ARE RUNNING A FEW DEGREES BELOW EARLIER FORECASTS... WHICH BRINGS ABOUT CONCERN WHEN ONE TRIES TO TAKE THE MODELS AT FACE VALUE. THE HIGH HAS SLID EAST TODAY AND SHOULD CONTINUE TO BE TRANSITORY AND WEAKEN A BIT INTO THE 1030S TONIGHT AS IT SHIFTS OFFSHORE... HOWEVER ITS STRENGTH IS STILL DECENT AND WHEN THE PRECIP STARTS AND LIKELY INSTIGATES AN AGEOSTROPHIC SURFACE WIND ADJUSTMENT TO A MORE UNIFORM NNE DIRECTION... THERE MAY BE AN HOUR OR TWO OF DRY AIR ADVECTION AND COUPLED WITH A LITTLE EVAPORATIVE COOLING IN THE LOW LEVELS... JUST ENOUGH TO BUMP LOW LEVEL THICKNESSES SLIGHTLY LOWER THAN FORECAST. THE 18Z GSO SOUNDING ARRIVED WITH LOW LEVEL THICKNESSES 5-9 METERS COLDER THAN MODEL FORECASTS. FINALLY... EVEN MODEL PROGS OF SURFACE WET BULB TEMPS ARE RUNNING COOLER BY A COUPLE OF DEGREES IN THE LATEST RUNS... THE RUC INCLUDED. IN SUMMARY... GIVEN THE STRONGER DRIER HIGH AND COOLER OBSERVED THERMAL PROFILE ALONG WITH MODEL PROGS TRENDING TO A COOLER SURFACE WET BULB... HAVE DECIDED TO EXPAND THE ADVISORY TO GUILFORD... DAVIDSON... RANDOLPH... AND ALAMANCE COUNTIES. A BIG ISSUE IS THE ARRIVAL OF PRECIP... WHICH LOOKS TO BE DELAYED BY A FEW HOURS AND WHICH SHOULD KEEP ICE ACCRUAL LIGHT BEFORE THE MASSIVE WARM AIR ADVECTION ENSUES TOWARD MIDNIGHT... AS 850 MB WINDS ACCELERATE UP TO 50-60 KTS. THIS STRONG WARMING ALOFT SHOULD ALSO ARRIVE IN MUCH OF THE NORTHEAST PIEDMONT EARLY ENOUGH SO THAT WHEN THE PRECIP ARRIVES THERE... IT SHOULD BE ALL RAIN... THUS DID NOT EXPAND THE ADVISORY ACROSS THE VA BORDER COUNTIES OF THE NE PIEDMONT AT THIS TIME. IF ANY BIT OF ZR DOES OCCUR... IT WOULD MOST LIKELY BE NORTH OF THE I-85 CORRIDOR... NORTH OF THE TRIANGLE. ANOTHER LIMITING FACTOR MAY BE THE PAVEMENT TEMPS WHICH ARE REPORTED TO BE IN THE 40S IN THE WINSTON-SALEM AREA... ALTHOUGH WE WILL NEED TO WATCH THESE VERY CAREFULLY DURING THIS EVENING. ELEVATED SURFACES ARE LIKELY TO BE MUCH COOLER HOWEVER. TEMPS TONIGHT SHOULD BE CLOSE TO THE CURRENT WET BULBS... AROUND 29 TO 38. WILL KEEP THE CURRENT TREND OF PRECIP MOVING OUT OF THE CENTRAL AND EASTERN CWA IN THE MORNING. PREFER THE COOLER MAV GUIDANCE HIGHS WITH SKIES CLEARING AND A BLUSTERY NW WIND. FRIDAY NIGHT THROUGH SATURDAY NIGHT: WITH A PORTION OF THE SURFACE HIGH PARKED OVERHEAD FRIDAY NIGHT AND WINDS DROPPING DOWN TO CALM... EXPECT CHILLY LOWS OF 19-27. LAST NIGHT'S LOWS BENEATH THIS AIR MASS WERE BELOW 0F SO WOULDN'T BE SURPRISED TO SEE QUITE A FEW TEENS. A DAMPENING WAVE ZIPS NORTHEASTWARD OVER THE AREA SATURDAY BUT HAS NO MOISTURE TO WORK WITH AND SHOULD BRING JUST A FEW CLOUDS AT MOST. WINDS THEN BECOME SOUTHWEST THROUGH THE COLUMN BUT THE SURFACE AIR MASS SHOULD ONLY BE ABLE TO MODIFY NOMINALLY... AND HIGH TEMPS SHOULD BE CLOSER TO NORMAL SATURDAY... ABOUT 48-53. -GIH LONG TERM (SUNDAY THROUGH THURSDAY)... A RATHER STRONG MID LEVEL VORT AXIS SWINGS THROUGH SUNDAY... THEN FOR SUNDAY NIGHT ONWARD... CONFIDENCE IS FAIRLY HIGH IN THE PERSISTENCE OF A MEAN TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD... ALTHOUGH CONSIDERABLE RUN-TO-RUN VARIATIONS IN THE GFS AND ECMWF MODELS AND THEIR LACK OF AGREEMENT WITH EACH OTHER BRING ABOUT MUCH LESS CONFIDENCE IN THE DETAILS WITHIN THIS FLOW REGIME. THE MORE CONSISTENT CANADIAN MODEL SEEMS TO BE AS GOOD A SOLUTION AS ANY... KEEPING THE TROUGH IN PLACE WITH RIDGING HOLDING IN THE WESTERN US AND PASSAGE OF VORT MAXIMA THROUGH NC INTO THE TROUGH BASE EVERY 2 DAYS OR SO. EXPECT LIMITED MOISTURE AVAILABILITY WITH SUCH A PATTERN... AND BARRING ANY PARTICULARLY VIGOROUS WAVES... THE PERIOD SHOULD REMAIN DRY WITH SOME CLOUDS FROM TIME TO TIME FROM EITHER A LITTLE MOISTURE TRAPPED BENEATH AN INVERSION ALOFT OR OROGRAPHIC ENHANCEMENT OF HIGHER CLOUDS WITH A DEEP AND SPEEDY W TO NW FLOW UP THROUGH THE COLUMN. TEMPS ROUGHLY A CATEGORY BELOW NORMAL EACH DAY. -GIH AVIATION... MID CLOUDINESS WILL THICKEN AND LOWER AS THIS AFTERNOON PROGRESSES. RAIN SHOULD DEVELOP FROM THE SOUTH AND WEST EARLY THIS EVENING. PRECIPITATION WILL TAKE THE FORM OF SLEET OR FREEZING RAIN FOR A FEW HOURS EARLY TONIGHT...MAINLY AT KINT AND KGSO. VISIBILITIES WILL DECREASE TO MVFR/IFR IN THE 00-06Z TIME FRAME AND SHOULD HOVER AROUND 1 MILE FROM 06Z THROUGH SUNRISE. CEILINGS WILL ALSO LOWER TO MVFR 00-04Z...THEN IFR OR LIFR 10-14Z WITH RAPID IMPROVEMENT WEST TO EAST FRI MORNING AS THE SURFACE LOW MOVES UP THE MID ATLANTIC COAST. -RFG && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FOR NCZ021>023-038-039 UNTIL 4 AM FRIDAY. && $$ SYNOPSIS... SHORT TERM...BADGETT/LOCKLEAR/REU nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 245 PM EST THU DEC 8 2005 .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... TONIGHT THROUGH FRIDAY: QUESTION MARKS STILL REMAIN REGARDING THIS PRECIP EVENT. AS EXPECTED THE PARENT HIGH TO OUR NORTH HAS BROKEN FREE FROM THE MORE ARCTIC MIDWEST HIGH... ALTHOUGH OUR HIGH IS STRONGER THAN PREVIOUSLY PROGGED AND THE DEWPOINTS ARE RUNNING A FEW DEGREES BELOW EARLIER FORECASTS... WHICH BRINGS ABOUT CONCERN WHEN ONE TRIES TO TAKE THE MODELS AT FACE VALUE. THE HIGH HAS SLID EAST TODAY AND SHOULD CONTINUE TO BE TRANSITORY AND WEAKEN A BIT INTO THE 1030S TONIGHT AS IT SHIFTS OFFSHORE... HOWEVER ITS STRENGTH IS STILL DECENT AND WHEN THE PRECIP STARTS AND LIKELY INSTIGATES AN AGEOSTROPHIC SURFACE WIND ADJUSTMENT TO A MORE UNIFORM NNE DIRECTION... THERE MAY BE AN HOUR OR TWO OF DRY AIR ADVECTION AND COUPLED WITH A LITTLE EVAPORATIVE COOLING IN THE LOW LEVELS... JUST ENOUGH TO BUMP LOW LEVEL THICKNESSES SLIGHTLY LOWER THAN FORECAST. THE 18Z GSO SOUNDING ARRIVED WITH LOW LEVEL THICKNESSES 5-9 METERS COLDER THAN MODEL FORECASTS. FINALLY... EVEN MODEL PROGS OF SURFACE WET BULB TEMPS ARE RUNNING COOLER BY A COUPLE OF DEGREES IN THE LATEST RUNS... THE RUC INCLUDED. IN SUMMARY... GIVEN THE STRONGER DRIER HIGH AND COOLER OBSERVED THERMAL PROFILE ALONG WITH MODEL PROGS TRENDING TO A COOLER SURFACE WET BULB... HAVE DECIDED TO EXPAND THE ADVISORY TO GUILFORD... DAVIDSON... RANDOLPH... AND ALAMANCE COUNTIES. A BIG ISSUE IS THE ARRIVAL OF PRECIP... WHICH LOOKS TO BE DELAYED BY A FEW HOURS AND WHICH SHOULD KEEP ICE ACCRUAL LIGHT BEFORE THE MASSIVE WARM AIR ADVECTION ENSUES TOWARD MIDNIGHT... AS 850 MB WINDS ACCELERATE UP TO 50-60 KTS. THIS STRONG WARMING ALOFT SHOULD ALSO ARRIVE IN MUCH OF THE NORTHEAST PIEDMONT EARLY ENOUGH SO THAT WHEN THE PRECIP ARRIVES THERE... IT SHOULD BE ALL RAIN... THUS DID NOT EXPAND THE ADVISORY ACROSS THE VA BORDER COUNTIES OF THE NE PIEDMONT AT THIS TIME. IF ANY BIT OF ZR DOES OCCUR... IT WOULD MOST LIKELY BE NORTH OF THE I-85 CORRIDOR... NORTH OF THE TRIANGLE. ANOTHER LIMITING FACTOR MAY BE THE PAVEMENT TEMPS WHICH ARE REPORTED TO BE IN THE 40S IN THE WINSTON-SALEM AREA... ALTHOUGH WE WILL NEED TO WATCH THESE VERY CAREFULLY DURING THIS EVENING. ELEVATED SURFACES ARE LIKELY TO BE MUCH COOLER HOWEVER. TEMPS TONIGHT SHOULD BE CLOSE TO THE CURRENT WET BULBS... AROUND 29 TO 38. WILL KEEP THE CURRENT TREND OF PRECIP MOVING OUT OF THE CENTRAL AND EASTERN CWA IN THE MORNING. PREFER THE COOLER MAV GUIDANCE HIGHS WITH SKIES CLEARING AND A BLUSTERY NW WIND. FRIDAY NIGHT THROUGH SATURDAY NIGHT: WITH A PORTION OF THE SURFACE HIGH PARKED OVERHEAD FRIDAY NIGHT AND WINDS DROPPING DOWN TO CALM... EXPECT CHILLY LOWS OF 19-27. LAST NIGHT'S LOWS BENEATH THIS AIR MASS WERE BELOW 0F SO WOULDN'T BE SURPRISED TO SEE QUITE A FEW TEENS. A DAMPENING WAVE ZIPS NORTHEASTWARD OVER THE AREA SATURDAY BUT HAS NO MOISTURE TO WORK WITH AND SHOULD BRING JUST A FEW CLOUDS AT MOST. WINDS THEN BECOME SOUTHWEST THROUGH THE COLUMN BUT THE SURFACE AIR MASS SHOULD ONLY BE ABLE TO MODIFY NOMINALLY... AND HIGH TEMPS SHOULD BE CLOSER TO NORMAL SATURDAY... ABOUT 48-53. -GIH && .LONG TERM (SUNDAY THROUGH THURSDAY)... A RATHER STRONG MID LEVEL VORT AXIS SWINGS THROUGH SUNDAY... THEN FOR SUNDAY NIGHT ONWARD... CONFIDENCE IS FAIRLY HIGH IN THE PERSISTENCE OF A MEAN TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD... ALTHOUGH CONSIDERABLE RUN-TO-RUN VARIATIONS IN THE GFS AND ECMWF MODELS AND THEIR LACK OF AGREEMENT WITH EACH OTHER BRING ABOUT MUCH LESS CONFIDENCE IN THE DETAILS WITHIN THIS FLOW REGIME. THE MORE CONSISTENT CANADIAN MODEL SEEMS TO BE AS GOOD A SOLUTION AS ANY... KEEPING THE TROUGH IN PLACE WITH RIDGING HOLDING IN THE WESTERN US AND PASSAGE OF VORT MAXIMA THROUGH NC INTO THE TROUGH BASE EVERY 2 DAYS OR SO. EXPECT LIMITED MOISTURE AVAILABILITY WITH SUCH A PATTERN... AND BARRING ANY PARTICULARLY VIGOROUS WAVES... THE PERIOD SHOULD REMAIN DRY WITH SOME CLOUDS FROM TIME TO TIME FROM EITHER A LITTLE MOISTURE TRAPPED BENEATH AN INVERSION ALOFT OR OROGRAPHIC ENHANCEMENT OF HIGHER CLOUDS WITH A DEEP AND SPEEDY W TO NW FLOW UP THROUGH THE COLUMN. TEMPS ROUGHLY A CATEGORY BELOW NORMAL EACH DAY. -GIH && .AVIATION... MID CLOUDINESS WILL THICKEN AND LOWER AS THIS AFTERNOON PROGRESSES. RAIN SHOULD DEVELOP FROM THE SOUTH AND WEST EARLY THIS EVENING. PRECIPITATION WILL TAKE THE FORM OF SLEET OR FREEZING RAIN FOR A FEW HOURS EARLY TONIGHT...MAINLY AT KINT AND KGSO. VISIBILITIES WILL DECREASE TO MVFR/IFR IN THE 00-06Z TIME FRAME AND SHOULD HOVER AROUND 1 MILE FROM 06Z THROUGH SUNRISE. CEILINGS WILL ALSO LOWER TO MVFR 00-04Z...THEN IFR OR LIFR 10-14Z WITH RAPID IMPROVEMENT WEST TO EAST FRI MORNING AS THE SURFACE LOW MOVES UP THE MID ATLANTIC COAST. -RFG && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FOR NCZ021>023-038-039 FROM 7 PM THURSDAY TO 4 AM FRIDAY. && $$ SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...RFG nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1110 PM EST THU DEC 8 2005 .SHORT TERM (REST OF TONIGHT)... HAVE UPDATED TO CLEAR HEADLINES FROM PARTS OF SOUTHERN FCST AREA. NO OTHER CHANGES PLANNED. && .PREVIOUS DISCUSSION... (ISSUED 928 PM EST THU DEC 8 2005) SHORT TERM (REST OF TONIGHT)... SURFACE ANALYSIS SHOWS DEEPENING LOW NEAR KMIE. WINDS ON THE BACK SIDE OF THE LOW ARE GUSTING TO 30 MPH. KILN RADAR SHOWING RETURNS BEGINNING TO DIMINISH AS BEST ISENTROPIC LIFT PULLS OFF TO THE EAST. DEFORMATION PRECIPITATION IS NOW KICKING IN AND IS A BIT LIGHTER. WARMER AIR HAS MOVED UP INTO THE TRI-STATE AND SOUTH CENTRAL OHIO OHIO AS MANY PLACES ARE AROUND TO ABOVE FREEZING. HAVE THROWN OUT AN UPDATE ALREADY TO INCREASE SNOW AMOUNTS IN THE PMH AREA. WILL THROW OUT ANOTHER UPDATE TO BRING AN END TO THE PRECIP SOONER. LATEST RUC SHOWING PRECIP ENDING QUICKLY AS DRY SLOT PUSHES EAST QUICKLY. 700 MB DEFORMATION IS MOVING THROUGH CURRENTLY AND IS WELL AHEAD OF 700 MB TROF. WILL LEAVE ALL HEADLINES WHERE THEY ARE AS SW WINDS ON THE BACKSIDE OF LOW WILL CREATE BLOWING SNOW ACROSS MUCH OF THE AREA AND MY CAUSE LIMBS AND POWER LINES TO BREAK CLOSER TO THE OHIO RIVER. NIGHT SHIFT WILL TAKE HEADLINES DOWN. TIPTON PREVIOUS DISCUSSION... (ISSUED 733 PM EST THU DEC 8 2005) AVIATION (0Z-0Z)... TRIED TO TIME IN THE DRY SLOT THAT WILL TURN OFF SNOW OVER THE OHIO VALLEY FROM SW-NE DURING THE LATE EVENING HOURS. ENOUGH LLVL MOISTURE AROUND AFTER 6Z...BUT UPSTREAM SITES HAVE SKC WHICH MAY SNEAK INTO CVG/LUK AND POSSIBLY ILN TONIGHT. MODELS ALL HAVE LINGERING LLVL MOISTURE...BUT LACK OF UPWARD MOTION AND WAA FROM THE 6-12Z TIME FRAME AT H8 WOULD SUGGEST THAT CLEAR SKIES OVER THE VERY LOW CEILINGS MAY WORK INTO THESE TAFS. KDAY AND KCMH APPEAR TO BE IN THE LEAST FAVORABLE AREA FOR THIS CLEARING...ONLY MENTIONED IT LATE TOMORROW BUT FEEL THAT IT COULD BE LESS CLOUDY THAN MODELS ARE FORECASTING...ESP WITH WAA SETTING UP ALL DAY LONG AT H8. FRANKS SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... SURFACE ANALYSIS SHOWS DEEPENING DOUBLE BARREL LOW FROM NASHVILLE TO SOUTH CHAMPAIGN ILLINOIS WITH SELY FLOW ACROSS THE FORECAST AREA. SATELLITE IMAGERY SHOWS CLOUD TOPS HAVE BEEN COOLING. KILN RADAR SHOWS RETURNS HAVE BEEN INCREASING IN COVERAGE AND INTENSITY ACROSS SW FORECAST AREA. ALL MODELS ARE IN GOOD AGREEMENT WITH TAKING NORTHERN PART OF SURFACE LOW UP INTO THE GREAT LAKES AS SOUTHERN LOW JUMPS TO THE EAST COAST. SUBTLE DIFFERENCES IN LOW LEVEL THICKNESSES BETWEEN MODELS. RUC IS THE COOLEST WITH NAM AND GFS BEING A BIT WARMER. AS A RESULT OF CURRENT TRENDS AND LATEST MODEL RUNS HAVE DECREASED SNOW AMOUNTS SOUTH OF I-71 CORRIDOR PER SOME MIX OF SLEET AND FZRA. HAVE TRIED TO STICK WITH 1300 DM (1000-850 MB THICKNESS) AS A DELINEATION OF SNOW/MIX OFF RUC. THE RUC SEEMS TO HAVE THE BEST FIT WITH CURRENT CONDITIONS. REASON FOR 1300 DM WAS WITH STRONG LIFT FOR THE NEXT 6 HOURS FIGURE DIABATIC COOLING WILL HELP TO KEEP SNOW GOING AT A WARMER THICKNESSES. WILL HAVE TO MONITOR. USING GARCIA METHOD HAVE GONE WITH A 4 TO 6 INCH RANGE NORTH OF I-71. RIGHT NOW THINK MAX SNOWFALL WILL BE IN A STRIP OF 10 TO 50 MILES NORTH OF I-71 WITH 5 TO 6 INCHES BEING THE AVERAGE MEASUREMENT. GRADIENT REALLY TIGHTENS UP OVERNIGHT AS SURFACE LOW GOES FROM POSITIVE TO NEGATIVE. THIS WILL CREATE WIND GUSTS TO 30 MPH AND ALONG WITH BLOWING AND DRIFTING OF SNOW. REST OF SHORT TERM FORECAST IS BENIGN. MAV TEMPS LOOK REASONABLE CONSIDERING THE SPREAD FROM MET AND FWC. WILL GO WITH MET FOR OVERNIGHT LOWS FRIDAY NIGHT WITH FRESH SNOW PACK AND CLEAR SKIES. IT SHOULD TAKE A LITTLE WHILE FOR THE SW WIND TO MIX IN. TIPTON LONG TERM (SUNDAY THROUGH THURSDAY)... RATHER COLD UNSETTLED WX PATTERN TO CONTINUE FOR OH VLY THRU EXTENDED. SFC LO TRACKING THRU GRT LKS TO BEGIN ON SUN. TRAILING COLD FRONT WILL TRACK THRU FCST AREA DURING DAY SUN USHERING IN REINFORCING SHOT OF ARCTIC AIR TO REGION. BNDRY LYR THICKNESSES REMAIN COLD ENUF THAT ALL PCPN WILL FALL IN FORM OF -SN. AT THIS POINT...PCPN LOOKS RELATIVELY LIGHT WITH POTENTIAL FOR RESIDUAL LK EFFECT -SHSN CONTINUING FOR SUN NIGHT. A SECONDARY MID LVL S/WV EMBEDDED IN MEAN LONGWAVE TROF WILL DROP INTO FCST AREA FOR MON...AND FEEL IT IS PRUDENT TO CONTINUE WITH A CHANCE FOR -SHSN. HI PRES THEN BRIEFLY BUILDS IN FOR TUES AS WEAK MID LVL RIDGING DVLPS AHEAD OF NEXT S/WV MOVING OUT OF NRN PLAINS. THIS FEATURE WILL TRACK INTO LWR GRT LKS FOR MIDWEEK AND PROVIDE ADDL CHANCES FOR PRIMARILY -SN. THERE IS SOME MODEL DISCREPANCY REGARDING THE HANDLING OF THIS SYSTEM. HAVE TRENDED WITH CONSENSUS SOLN OF BRINGING S/WV THRU REGION ON WED...ALTHOUGH 12Z GFS NOW DELAYING THIS SYSTEM UNTIL ERLY THURS. WILL GO WITH 30 POPS WED...BUT HAVE LINGERED LO CHC POPS INTO THURS TO ACCOUNT FOR 12Z GFS SOLN. HAVE CONTINUED TREND OF KEEPING TEMPS BELOW NORMAL AND LOWER THAN MEX/MEN GUID. TAKING INTO CONSIDERATION POTENTIAL SNOW COVER FROM EVENT TONIGHT AND LARGE UPR LVL TROF FOR EASTERN CONUS AS WELL AS POTENTIAL FOR MORE CLOUDS/PCPN IN EXTENDED...COLDER TEMPS CERTAINLY APPEAR MORE PLAUSIBLE. HAVE HIGHS GENERALLY IN U20S/L30S THRU BULK OF EXTENDED PERIOD. RYAN && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAVY SNOW WARNING FOR OHZ026-034-035-042>046-051>056-060>063- 070>072 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR OHZ064-065-073-074 UNTIL 6 AM FRIDAY. KY...NONE. IN...HEAVY SNOW WARNING FOR INZ050-058-059-066 UNTIL 6 AM FRIDAY. && $$ SHORT TERM... oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 928 PM EST THU DEC 8 2005 .SHORT TERM (REST OF TONIGHT)... SURFACE ANALYSIS SHOWS DEEPENING LOW NEAR KMIE. WINDS ON THE BACK SIDE OF THE LOW ARE GUSTING TO 30 MPH. KILN RADAR SHOWING RETURNS BEGINNING TO DIMINISH AS BEST ISENTROPIC LIFT PULLS OFF TO THE EAST. DEFORMATION PRECIPITATION IS NOW KICKING IN AND IS A BIT LIGHTER. WARMER AIR HAS MOVED UP INTO THE TRI-STATE AND SOUTH CENTRAL OHIO OHIO AS MANY PLACES ARE AROUND TO ABOVE FREEZING. HAVE THROWN OUT AN UPDATE ALREADY TO INCREASE SNOW AMOUNTS IN THE PMH AREA. WILL THROW OUT ANOTHER UPDATE TO BRING AN END TO THE PRECIP SOONER. LATEST RUC SHOWING PRECIP ENDING QUICKLY AS DRY SLOT PUSHES EAST QUICKLY. 700 MB DEFORMATION IS MOVING THROUGH CURRENTLY AND IS WELL AHEAD OF 700 MB TROF. WILL LEAVE ALL HEADLINES WHERE THEY ARE AS SW WINDS ON THE BACKSIDE OF LOW WILL CREATE BLOWING SNOW ACROSS MUCH OF THE AREA AND MY CAUSE LIMBS AND POWER LINES TO BREAK CLOSER TO THE OHIO RIVER. NIGHT SHIFT WILL TAKE HEADLINES DOWN. TIPTON && .PREVIOUS DISCUSSION... (ISSUED 733 PM EST THU DEC 8 2005) AVIATION (0Z-0Z)... TRIED TO TIME IN THE DRY SLOT THAT WILL TURN OFF SNOW OVER THE OHIO VALLEY FROM SW-NE DURING THE LATE EVENING HOURS. ENOUGH LLVL MOISTURE AROUND AFTER 6Z...BUT UPSTREAM SITES HAVE SKC WHICH MAY SNEAK INTO CVG/LUK AND POSSIBLY ILN TONIGHT. MODELS ALL HAVE LINGERING LLVL MOISTURE...BUT LACK OF UPWARD MOTION AND WAA FROM THE 6-12Z TIME FRAME AT H8 WOULD SUGGEST THAT CLEAR SKIES OVER THE VERY LOW CEILINGS MAY WORK INTO THESE TAFS. KDAY AND KCMH APPEAR TO BE IN THE LEAST FAVORABLE AREA FOR THIS CLEARING...ONLY MENTIONED IT LATE TOMORROW BUT FEEL THAT IT COULD BE LESS CLOUDY THAN MODELS ARE FORECASTING...ESP WITH WAA SETTING UP ALL DAY LONG AT H8. FRANKS SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... SURFACE ANALYSIS SHOWS DEEPENING DOUBLE BARREL LOW FROM NASHVILLE TO SOUTH CHAMPAIGN ILLINOIS WITH SELY FLOW ACROSS THE FORECAST AREA. SATELLITE IMAGERY SHOWS CLOUD TOPS HAVE BEEN COOLING. KILN RADAR SHOWS RETURNS HAVE BEEN INCREASING IN COVERAGE AND INTENSITY ACROSS SW FORECAST AREA. ALL MODELS ARE IN GOOD AGREEMENT WITH TAKING NORTHERN PART OF SURFACE LOW UP INTO THE GREAT LAKES AS SOUTHERN LOW JUMPS TO THE EAST COAST. SUBTLE DIFFERENCES IN LOW LEVEL THICKNESSES BETWEEN MODELS. RUC IS THE COOLEST WITH NAM AND GFS BEING A BIT WARMER. AS A RESULT OF CURRENT TRENDS AND LATEST MODEL RUNS HAVE DECREASED SNOW AMOUNTS SOUTH OF I-71 CORRIDOR PER SOME MIX OF SLEET AND FZRA. HAVE TRIED TO STICK WITH 1300 DM (1000-850 MB THICKNESS) AS A DELINEATION OF SNOW/MIX OFF RUC. THE RUC SEEMS TO HAVE THE BEST FIT WITH CURRENT CONDITIONS. REASON FOR 1300 DM WAS WITH STRONG LIFT FOR THE NEXT 6 HOURS FIGURE DIABATIC COOLING WILL HELP TO KEEP SNOW GOING AT A WARMER THICKNESSES. WILL HAVE TO MONITOR. USING GARCIA METHOD HAVE GONE WITH A 4 TO 6 INCH RANGE NORTH OF I-71. RIGHT NOW THINK MAX SNOWFALL WILL BE IN A STRIP OF 10 TO 50 MILES NORTH OF I-71 WITH 5 TO 6 INCHES BEING THE AVERAGE MEASUREMENT. GRADIENT REALLY TIGHTENS UP OVERNIGHT AS SURFACE LOW GOES FROM POSITIVE TO NEGATIVE. THIS WILL CREATE WIND GUSTS TO 30 MPH AND ALONG WITH BLOWING AND DRIFTING OF SNOW. REST OF SHORT TERM FORECAST IS BENIGN. MAV TEMPS LOOK REASONABLE CONSIDERING THE SPREAD FROM MET AND FWC. WILL GO WITH MET FOR OVERNIGHT LOWS FRIDAY NIGHT WITH FRESH SNOW PACK AND CLEAR SKIES. IT SHOULD TAKE A LITTLE WHILE FOR THE SW WIND TO MIX IN. TIPTON LONG TERM (SUNDAY THROUGH THURSDAY)... RATHER COLD UNSETTLED WX PATTERN TO CONTINUE FOR OH VLY THRU EXTENDED. SFC LO TRACKING THRU GRT LKS TO BEGIN ON SUN. TRAILING COLD FRONT WILL TRACK THRU FCST AREA DURING DAY SUN USHERING IN REINFORCING SHOT OF ARCTIC AIR TO REGION. BNDRY LYR THICKNESSES REMAIN COLD ENUF THAT ALL PCPN WILL FALL IN FORM OF -SN. AT THIS POINT...PCPN LOOKS RELATIVELY LIGHT WITH POTENTIAL FOR RESIDUAL LK EFFECT -SHSN CONTINUING FOR SUN NIGHT. A SECONDARY MID LVL S/WV EMBEDDED IN MEAN LONGWAVE TROF WILL DROP INTO FCST AREA FOR MON...AND FEEL IT IS PRUDENT TO CONTINUE WITH A CHANCE FOR -SHSN. HI PRES THEN BRIEFLY BUILDS IN FOR TUES AS WEAK MID LVL RIDGING DVLPS AHEAD OF NEXT S/WV MOVING OUT OF NRN PLAINS. THIS FEATURE WILL TRACK INTO LWR GRT LKS FOR MIDWEEK AND PROVIDE ADDL CHANCES FOR PRIMARILY -SN. THERE IS SOME MODEL DISCREPANCY REGARDING THE HANDLING OF THIS SYSTEM. HAVE TRENDED WITH CONSENSUS SOLN OF BRINGING S/WV THRU REGION ON WED...ALTHOUGH 12Z GFS NOW DELAYING THIS SYSTEM UNTIL ERLY THURS. WILL GO WITH 30 POPS WED...BUT HAVE LINGERED LO CHC POPS INTO THURS TO ACCOUNT FOR 12Z GFS SOLN. HAVE CONTINUED TREND OF KEEPING TEMPS BELOW NORMAL AND LOWER THAN MEX/MEN GUID. TAKING INTO CONSIDERATION POTENTIAL SNOW COVER FROM EVENT TONIGHT AND LARGE UPR LVL TROF FOR EASTERN CONUS AS WELL AS POTENTIAL FOR MORE CLOUDS/PCPN IN EXTENDED...COLDER TEMPS CERTAINLY APPEAR MORE PLAUSIBLE. HAVE HIGHS GENERALLY IN U20S/L30S THRU BULK OF EXTENDED PERIOD. RYAN && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAVY SNOW WARNING FOR OHZ026-034-035-042>046-051>056-060>063- 070>072-077 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR OHZ064-065-073-074-078>080 UNTIL 6 AM FRIDAY. ...WINTER WEATHER ADVISORY FOR OHZ081-082-088 UNTIL 6 AM FRIDAY. KY...WINTER STORM WARNING FOR KYZ089-090-094>099 UNTIL 6 AM FRIDAY. ...HEAVY SNOW WARNING FOR KYZ091>093 UNTIL 6 AM FRIDAY. ...WINTER WEATHER ADVISORY FOR KYZ100 UNTIL 6 AM FRIDAY. IN...HEAVY SNOW WARNING FOR INZ050-058-059-066-073>075-080 UNTIL 6 AM FRIDAY. && $$ SHORT TERM... oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 733 PM EST THU DEC 8 2005 .AVIATION (0Z-0Z)... TRIED TO TIME IN THE DRY SLOT THAT WILL TURN OFF SNOW OVER THE OHIO VALLEY FROM SW-NE DURING THE LATE EVENING HOURS. ENOUGH LLVL MOISTURE AROUND AFTER 6Z...BUT UPSTREAM SITES HAVE SKC WHICH MAY SNEAK INTO CVG/LUK AND POSSIBLY ILN TONIGHT. MODELS ALL HAVE LINGERING LLVL MOISTURE...BUT LACK OF UPWARD MOTION AND WAA FROM THE 6-12Z TIME FRAME AT H8 WOULD SUGGEST THAT CLEAR SKIES OVER THE VERY LOW CEILINGS MAY WORK INTO THESE TAFS. KDAY AND KCMH APPEAR TO BE IN THE LEAST FAVORABLE AREA FOR THIS CLEARING...ONLY MENTIONED IT LATE TOMORROW BUT FEEL THAT IT COULD BE LESS CLOUDY THAN MODELS ARE FORECASTING...ESP WITH WAA SETTING UP ALL DAY LONG AT H8. FRANKS && .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... SURFACE ANALYSIS SHOWS DEEPENING DOUBLE BARREL LOW FROM NASHVILLE TO SOUTH CHAMPAIGN ILLINOIS WITH SELY FLOW ACROSS THE FORECAST AREA. SATELLITE IMAGERY SHOWS CLOUD TOPS HAVE BEEN COOLING. KILN RADAR SHOWS RETURNS HAVE BEEN INCREASING IN COVERAGE AND INTENSITY ACROSS SW FORECAST AREA. ALL MODELS ARE IN GOOD AGREEMENT WITH TAKING NORTHERN PART OF SURFACE LOW UP INTO THE GREAT LAKES AS SOUTHERN LOW JUMPS TO THE EAST COAST. SUBTLE DIFFERENCES IN LOW LEVEL THICKNESSES BETWEEN MODELS. RUC IS THE COOLEST WITH NAM AND GFS BEING A BIT WARMER. AS A RESULT OF CURRENT TRENDS AND LATEST MODEL RUNS HAVE DECREASED SNOW AMOUNTS SOUTH OF I-71 CORRIDOR PER SOME MIX OF SLEET AND FZRA. HAVE TRIED TO STICK WITH 1300 DM (1000-850 MB THICKNESS) AS A DELINEATION OF SNOW/MIX OFF RUC. THE RUC SEEMS TO HAVE THE BEST FIT WITH CURRENT CONDITIONS. REASON FOR 1300 DM WAS WITH STRONG LIFT FOR THE NEXT 6 HOURS FIGURE DIABATIC COOLING WILL HELP TO KEEP SNOW GOING AT A WARMER THICKNESSES. WILL HAVE TO MONITOR. USING GARCIA METHOD HAVE GONE WITH A 4 TO 6 INCH RANGE NORTH OF I-71. RIGHT NOW THINK MAX SNOWFALL WILL BE IN A STRIP OF 10 TO 50 MILES NORTH OF I-71 WITH 5 TO 6 INCHES BEING THE AVERAGE MEASUREMENT. GRADIENT REALLY TIGHTENS UP OVERNIGHT AS SURFACE LOW GOES FROM POSITIVE TO NEGATIVE. THIS WILL CREATE WIND GUSTS TO 30 MPH AND ALONG WITH BLOWING AND DRIFTING OF SNOW. REST OF SHORT TERM FORECAST IS BENIGN. MAV TEMPS LOOK REASONABLE CONSIDERING THE SPREAD FROM MET AND FWC. WILL GO WITH MET FOR OVERNIGHT LOWS FRIDAY NIGHT WITH FRESH SNOW PACK AND CLEAR SKIES. IT SHOULD TAKE A LITTLE WHILE FOR THE SW WIND TO MIX IN. TIPTON && .LONG TERM (SUNDAY THROUGH THURSDAY)... RATHER COLD UNSETTLED WX PATTERN TO CONTINUE FOR OH VLY THRU EXTENDED. SFC LO TRACKING THRU GRT LKS TO BEGIN ON SUN. TRAILING COLD FRONT WILL TRACK THRU FCST AREA DURING DAY SUN USHERING IN REINFORCING SHOT OF ARCTIC AIR TO REGION. BNDRY LYR THICKNESSES REMAIN COLD ENUF THAT ALL PCPN WILL FALL IN FORM OF -SN. AT THIS POINT...PCPN LOOKS RELATIVELY LIGHT WITH POTENTIAL FOR RESIDUAL LK EFFECT -SHSN CONTINUING FOR SUN NIGHT. A SECONDARY MID LVL S/WV EMBEDDED IN MEAN LONGWAVE TROF WILL DROP INTO FCST AREA FOR MON...AND FEEL IT IS PRUDENT TO CONTINUE WITH A CHANCE FOR -SHSN. HI PRES THEN BRIEFLY BUILDS IN FOR TUES AS WEAK MID LVL RIDGING DVLPS AHEAD OF NEXT S/WV MOVING OUT OF NRN PLAINS. THIS FEATURE WILL TRACK INTO LWR GRT LKS FOR MIDWEEK AND PROVIDE ADDL CHANCES FOR PRIMARILY -SN. THERE IS SOME MODEL DISCREPANCY REGARDING THE HANDLING OF THIS SYSTEM. HAVE TRENDED WITH CONSENSUS SOLN OF BRINGING S/WV THRU REGION ON WED...ALTHOUGH 12Z GFS NOW DELAYING THIS SYSTEM UNTIL ERLY THURS. WILL GO WITH 30 POPS WED...BUT HAVE LINGERED LO CHC POPS INTO THURS TO ACCOUNT FOR 12Z GFS SOLN. HAVE CONTINUED TREND OF KEEPING TEMPS BELOW NORMAL AND LOWER THAN MEX/MEN GUID. TAKING INTO CONSIDERATION POTENTIAL SNOW COVER FROM EVENT TONIGHT AND LARGE UPR LVL TROF FOR EASTERN CONUS AS WELL AS POTENTIAL FOR MORE CLOUDS/PCPN IN EXTENDED...COLDER TEMPS CERTAINLY APPEAR MORE PLAUSIBLE. HAVE HIGHS GENERALLY IN U20S/L30S THRU BULK OF EXTENDED PERIOD. RYAN && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAVY SNOW WARNING FOR OHZ026-034-035-042>046-051>056-060>063- 070>072-077 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR OHZ064-065-073-074-078>080 UNTIL 6 AM FRIDAY. ...WINTER WEATHER ADVISORY FOR OHZ081-082-088 UNTIL 6 AM FRIDAY. KY...WINTER STORM WARNING FOR KYZ089-090-094>096 UNTIL 6 AM FRIDAY. ...HEAVY SNOW WARNING FOR KYZ091>093 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR KYZ097>099 UNTIL 6 AM FRIDAY. ...WINTER WEATHER ADVISORY FOR KYZ100 UNTIL 6 AM FRIDAY. IN...HEAVY SNOW WARNING FOR INZ050-058-059-066-073>075-080 UNTIL 6 AM FRIDAY. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 412 PM EST THU DEC 8 2005 .SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... SURFACE ANALYSIS SHOWS DEEPENING DOUBLE BARREL LOW FROM NASHVILLE TO SOUTH CHAMPAIGN ILLINOIS WITH SELY FLOW ACROSS THE FORECAST AREA. SATELLITE IMAGERY SHOWS CLOUD TOPS HAVE BEEN COOLING. KILN RADAR SHOWS RETURNS HAVE BEEN INCREASING IN COVERAGE AND INTENSITY ACROSS SW FORECAST AREA. ALL MODELS ARE IN GOOD AGREEMENT WITH TAKING NORTHERN PART OF SURFACE LOW UP INTO THE GREAT LAKES AS SOUTHERN LOW JUMPS TO THE EAST COAST. SUBTLE DIFFERENCES IN LOW LEVEL THICKNESSES BETWEEN MODELS. RUC IS THE COOLEST WITH NAM AND GFS BEING A BIT WARMER. AS A RESULT OF CURRENT TRENDS AND LATEST MODEL RUNS HAVE DECREASED SNOW AMOUNTS SOUTH OF I-71 CORRIDOR PER SOME MIX OF SLEET AND FZRA. HAVE TRIED TO STICK WITH 1300 DM (1000-850 MB THICKNESS) AS A DELINEATION OF SNOW/MIX OFF RUC. THE RUC SEEMS TO HAVE THE BEST FIT WITH CURRENT CONDITIONS. REASON FOR 1300 DM WAS WITH STRONG LIFT FOR THE NEXT 6 HOURS FIGURE DIABATIC COOLING WILL HELP TO KEEP SNOW GOING AT A WARMER THICKNESSES. WILL HAVE TO MONITOR. USING GARCIA METHOD HAVE GONE WITH A 4 TO 6 INCH RANGE NORTH OF I-71. RIGHT NOW THINK MAX SNOWFALL WILL BE IN A STRIP OF 10 TO 50 MILES NORTH OF I-71 WITH 5 TO 6 INCHES BEING THE AVERAGE MEASUREMENT. GRADIENT REALLY TIGHTENS UP OVERNIGHT AS SURFACE LOW GOES FROM POSITIVE TO NEGATIVE. THIS WILL CREATE WIND GUSTS TO 30 MPH AND ALONG WITH BLOWING AND DRIFTING OF SNOW. REST OF SHORT TERM FORECAST IS BENIGN. MAV TEMPS LOOK REASONABLE CONSIDERING THE SPREAD FROM MET AND FWC. WILL GO WITH MET FOR OVERNIGHT LOWS FRIDAY NIGHT WITH FRESH SNOW PACK AND CLEAR SKIES. IT SHOULD TAKE A LITTLE WHILE FOR THE SW WIND TO MIX IN. TIPTON && .LONG TERM (SUNDAY THROUGH THURSDAY)... RATHER COLD UNSETTLED WX PATTERN TO CONTINUE FOR OH VLY THRU EXTENDED. SFC LO TRACKING THRU GRT LKS TO BEGIN ON SUN. TRAILING COLD FRONT WILL TRACK THRU FCST AREA DURING DAY SUN USHERING IN REINFORCING SHOT OF ARCTIC AIR TO REGION. BNDRY LYR THICKNESSES REMAIN COLD ENUF THAT ALL PCPN WILL FALL IN FORM OF -SN. AT THIS POINT...PCPN LOOKS RELATIVELY LIGHT WITH POTENTIAL FOR RESIDUAL LK EFFECT -SHSN CONTINUING FOR SUN NIGHT. A SECONDARY MID LVL S/WV EMBEDDED IN MEAN LONGWAVE TROF WILL DROP INTO FCST AREA FOR MON...AND FEEL IT IS PRUDENT TO CONTINUE WITH A CHANCE FOR -SHSN. HI PRES THEN BRIEFLY BUILDS IN FOR TUES AS WEAK MID LVL RIDGING DVLPS AHEAD OF NEXT S/WV MOVING OUT OF NRN PLAINS. THIS FEATURE WILL TRACK INTO LWR GRT LKS FOR MIDWEEK AND PROVIDE ADDL CHANCES FOR PRIMARILY -SN. THERE IS SOME MODEL DISCREPANCY REGARDING THE HANDLING OF THIS SYSTEM. HAVE TRENDED WITH CONSENSUS SOLN OF BRINGING S/WV THRU REGION ON WED...ALTHOUGH 12Z GFS NOW DELAYING THIS SYSTEM UNTIL ERLY THURS. WILL GO WITH 30 POPS WED...BUT HAVE LINGERED LO CHC POPS INTO THURS TO ACCOUNT FOR 12Z GFS SOLN. HAVE CONTINUED TREND OF KEEPING TEMPS BELOW NORMAL AND LOWER THAN MEX/MEN GUID. TAKING INTO CONSIDERATION POTENTIAL SNOW COVER FROM EVENT TONIGHT AND LARGE UPR LVL TROF FOR EASTERN CONUS AS WELL AS POTENTIAL FOR MORE CLOUDS/PCPN IN EXTENDED...COLDER TEMPS CERTAINLY APPEAR MORE PLAUSIBLE. HAVE HIGHS GENERALLY IN U20S/L30S THRU BULK OF EXTENDED PERIOD. RYAN && .PREVIOUS DISCUSSION... (ISSUED 111 PM EST THU DEC 8 2005) .AVIATION (18Z-18Z)... LOW PRESSURE TO MOVE ACROSS CWA TONIGHT. MIXED PRECIPITATION IN ADVANCE OF LOW MOVING INTO CVG...LUK BY 20Z. LOOKING AT THICKNESS VALUES SHOULD TRANSLATE NORTH INTO ILN...CMH AND LCK BY 00Z. SHOULD BE ALL SNOW AT DAY. HEAVIER PCPN SHOULD CAUSE PRECIP TO RETURN TO ALL SNOW THIS EVENING WITH CAA TONIGHT. MOISTURE CUTS OFF AROUND 03Z TO 06Z FROM WEST TO EAST. EXPECT LINGERING LOW CLOUDS AND SCATTERED -SN THROUGH 12Z. CIGS WILL RISE FROM 12Z TO 18Z. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAVY SNOW WARNING FOR OHZ026-034-035-042>046-051>056-060>063- 070>072-077 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR OHZ064-065-073-074-078>080 UNTIL 6 AM FRIDAY. ...WINTER WEATHER ADVISORY FOR OHZ081-082-088 UNTIL 6 AM FRIDAY. KY...WINTER STORM WARNING FOR KYZ089-090-094>096 UNTIL 6 AM FRIDAY. ...HEAVY SNOW WARNING FOR KYZ091>093 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR KYZ097>099 UNTIL 6 AM FRIDAY. ...WINTER WEATHER ADVISORY FOR KYZ100 UNTIL 6 AM FRIDAY. IN...HEAVY SNOW WARNING FOR INZ050-058-059-066-073>075-080 UNTIL 6 AM FRIDAY. && $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1025 AM EST THU DEC 8 2005 .SHORT TERM (THIS AFTERNOON)... NO MAJOR MID COURSE CORRECTIONS PLANNED AT THIS TIME...BUT A DELAY IN THE ONSET OF PRECIPITATION APPEARS LIKELY...GIVEN THE TRENDS ON AREA RADARS. A QUICK LOOK AT THE RUC AND THE 12Z ETA SUGGESTS IT WILL BE CLOSER TO MID/LATE AFTERNOON FOR STEADY PRECIP TO DEVELOP OVER THE SW...AND CLOSER TO EARLY EVENING OVER THE NE...BASED ON UPGLIDE FORECAST ON 295K SURFACE AND HOW LONG IT WILL TAKE TO SATURATE LOW LEVELS. ESSENTIALLY WHAT THIS DOES IS FORCE ABOUT A 3 HOUR DELAY IN THE TIMING...WHICH WILL BE REFLECTED IN THE UPDATED GRIDS/TEXT PRODUCTS. TEMPS/DEWPOINTS WILL BE ADJUSTED A BIT AS WELL TO REFLECT THE SLIGHT DELAY IN PRECIP DEVELOPMENT. OTHERWISE...WILL STAY THE COURSE WITH COLLECTION OF WARNINGS AND ADVISORIES FOR THE TIME BEING...AND WILL REVISIT THE ISSUE DURING THE MID AFTERNOON. && .PREVIOUS DISCUSSION... ISSUED AT 432 AM. SHORT TERM (TODAY THROUGH FRIDAY)... LATEST SFC OBS SHOWING WEDGE DEVELOPING THIS MORNING ACROSS THE WESTERN CAROLINAS AND EXTREME NE GA. NE FLOW HAS PICKED UP OVER THE PAST SEVERAL HOURS WITH PRESSURE RISES AND INCREASING DWPT DEPRESSIONS. BY SUNRISE...MOST OF NC AND NRN PORTIONS OF SC SHOULD HAVE TEMPERATURES AT OR BELOW FREEZING. THICK CLOUD COVER AND BL CAA SHOULD SLOW WARMING SIGNIFICANTLY THIS MORNING. BOTH THE NAM AND THE GFS DELAY PRECIP MOVE NORTH OVER THE FA UNTIL 18Z THIS AFTERNOON. SINCE PRECIP ONSET IS RATHER LATE IN THE DAY...TEMPERATURES ACROSS THE FA WILL BE MARGINAL FOR WINTER PRECIPITATION. THE UNCERTAINTY SURROUNDING PRECIP TIMING AND COVERAGE ALONG WITH CRITICAL TEMPERATURES RESULTS IN AN EXTREMELY COMPLICATED WINTER WEATHER FORECAST. BY 0Z FRI...BOTH THE GFS AND NAM SHOW CATE COVERAGE OF QPF. BASED ON THE WEDGE SIGNATURE...WET BULB TEMPERATURES ALONG AND JUST EAST OF THE ESCARPMENT SHOULD REMAIN AT OR JUST BELOW FREEZING. PARTIAL THICKNESSES COMBINED WITH NOMOGRAM YIELDS A WINTRY MIX. WARM NOSE AT H8 APPEARS WARM ENOUGH TO RULE OUT SN AND LIMIT PL AFTER 18Z TODAY. MAIN CONCERN TODAY AND TONIGHT WILL BE FZRA AND FZDZ. GENERALLY...TEMPERATURES SHOULD WARM FROM THE SOUTH AND EAST...SQUEEZING FREEZING TEMPERATURES INTO THE MTNS VALLEYS AND EASTERN UPSLOPE. THIS SHOULD RESULT IN PROLONG PERIODS OF FREEZING PRECIPITATION ACROSS THE NC FOOTHILLS AND MTN VALLEYS. BASED ON THE TOPOGRAPHY ORIENTATION...PRECIP TIMING...AND EXPECTED TEMPERATURES...ANY DAMAGING ICE ACCUMULATIONS SHOULD BE ISOLATED ACROSS THE CWA. SINCE 1998...ISOLATED DAMAGING ICE EVENTS FAVOR CERTAIN AREAS ACROSS THE MTNS...ESPECIALLY HENDERSON AND MITCHELL COUNTIES. WE WILL HIGHLIGHT THESE COUNTIES ALONG WITH AVERY COUNTY WITH A ICE STORM WARNING FOR DAMAGING ICE ACCUMULATIONS THIS AFTERNOON AND TONIGHT. WILL ISSUE AN FREEZING RAIN ADVISORY FOR THE ADJACENT NC FOOTHILLS...FRENCH BROAD RIVER COUNTIES...ALONG WITH YANCEY COUNTY. THE AREAS WITHIN THE ADVISORY CAN EXPECT LESS THAN A QUARTER OF AN INCH OF ICE. PRECIPITATION SHOULD RAPIDLY END FROM WEST TO EAST AROUND SUNRISE FRIDAY. TEMPERATURES ACROSS MOST OF NC AND PORTIONS OF SC WILL FALL BELOW FREEZING. IF ANY MOISTURE REMAINS ON THE ROADS...ESPECIALLY OVERPASSES...THEN ICY AREAS WILL LIKELY DEVELOP...EVEN WHERE WINTER WEATHER DID NOT OCCUR. IN ADDITION...WINDY CONDITIONS SHOULD DEVELOP LATE TONIGHT OVER THE MTNS AND SHOULD REMAIN THROUGH FRI AM. THESE WINDS ARE EXPECTED TO BECOME QUITE GUSTY BY SUNRISE...WITH GUSTS OVER 40 MPH. THESE WINDS COULD EASILY BREAK POWER LINES AND TREE LIMBS COVERED IN ICE. WILL ISSUE A SPECIAL WEATHER STATEMENT TO COVER THESE CONCERNS. LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... GFS CONTINUES TO INDICATE A CLIPPER APPROACHING THE SOUTHERN APPALACHIANS FROM THE NW SUN AND MON. AS THE DISTURBANCE APPROACHES...MOISTURE AND NW FLOW WILL INCREASE ALONG THE TN/NC STATE LINE. THIS SHOULD RESULT IN ACCUMULATING SNOW ACROSS THE WEST FACING SLOPES OF THE NC MTNS. I INCREASED POPS AND DECREASED TEMPS TO BETTER LINE UP WITH THE SYSTEM. OTHERWISE...ONLY MINOR CHANGES WERE MADE TO THE EXTENDED GRIDS. NED && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...ICE STORM WARNING FOR NCZ033-050-065 FROM NOON THURSDAY TO 6 AM FRIDAY. ...FREEZING RAIN ADVISORY FOR NCZ034-048-049-053>055-063-064-066- 067 FROM NOON THURSDAY TO 6 AM FRIDAY. SC...NONE. && $$ SHORT TERM (UPDATE)...MOORE sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 1015 AM EST THU DEC 8 2005 .SHORT TERM (REST OF TODAY THROUGH TONIGHT)... INCREASING ISENTROPIC LIFT SHOULD RESULT IN RAIN DEVELOPMENT FROM SOUTH TO NORTH THIS AFTERNOON. BASED ON THE LATEST RUC EXPECT THE RAIN WILL DEVELOP EARLY THIS AFTERNOON IN THE CSRA...MID AFTERNOON IN THE CENTRAL PART AND LATE THIS AFTERNOON IN THE NORTH PART. SURFACE WET BULB TEMPERATURES HAVE RISEN ABOVE FREEZING IN THE NORTH PART SO EXPECT IT WILL BE ALL RAIN. SOME DRY LAYERS ALOFT AND EVAPORATIVE COOLING COULD HELP CAUSE A LITTLE SLEET IN THE NORTH PART AT THE START BUT THE CHANCE APPEARS TOO LOW TO FORECAST AT THIS TIME. && .PREVIOUS DISCUSSION... (ISSUED 339 AM EST THU DEC 8 2005) SHORT TERM (TODAY THROUGH SATURDAY)... SIGNIFICANT UPPER LOW OVER THE CENTRAL PLAINS WILL MOVE TO THE EAST TODAY AND OFF THE NE COAST FRIDAY NIGHT. SUB-TROPICAL JET WILL BRING PLENTY OF MOISTURE ACROSS THE REGION TODAY AS HIGH AND MID LEVEL CLOUDS WILL GRADUALLY THICKEN THROUGH THE DAY TODAY. WEAK SFC LOW WILL GET BETTER ORGANIZED TODAY AS IT APPROACHES THE FLORIDA WEST COAST TONIGHT. THE LOW IS EXPECTED TO MOVE UP ALONG THE SOUTH CAROLINA COAST OVERNIGHT AND CONTINUE NE ON FRIDAY AS IT RAPIDLY DEEPENS THROUGH SATURDAY OVER THE NORTH ATLANTIC. SFC HIGH OVER THE MID ATLANTIC REGION WILL QUICKLY MOVE OUT TO SEA AS TEMPERATURES WILL REMAIN COLD THROUGH THE PERIOD...BUT NOT COLD ENOUGH FOR ANY WINTRY TYPE PRECIPITATION ACROSS THE MIDLANDS AND INTO THE CENTRAL SAVANNAH RIVER AREA. HIGH PRESSURE CENTER IS KEEPING A DRY LAYER AROUND 4 THOUSAND FEET DEEP ACROSS THE AREA AND IT WILL TAKE SOME TIME FOR THE SUB-TROPICAL MOISTURE TO BECOME DEEP ENOUGH TO OVERCOME THIS VERY DRY AIRMASS. WE DO NOT EXPECT ANY SIGNIFICANT PRECIPITATION TO BEGIN UNTIL AFTER 21Z THIS AFTERNOON. A FEW PELLETS OF SLEET MY MAKE IT THROUGH THE DRY AIR MASS OVER NORTHERN LANCASTER COUNTY BY MIDDAY TODAY, BUT DO NOT EXPECT ANY ACCUMULATION OR ANY TRAVEL PROBLEMS. THE STRONGEST ISENTROPIC LIFT OCCURS OVERNIGHT TONIGHT WITH A LOW LEVEL JET AROUND 50 TO 60 KTS. WARM ATLANTIC AIR WILL LIFT OVER THE COOL POOL OF AIR OVER THE MIDLANDS AND WILL CREATE A VERY WIDESPREAD AREA OF MODERATE TO HEAVY RAIN ACROSS THE FORECAST AREA. HAVE MENTIONED IN THE ZONES...PERIODS OF HEAVY RAIN. COULD SEE TOTAL RAINFALL AMOUNTS ACROSS THE AREA OF ONE TO TWO INCHES FOR THE EVENT. RAIN WILL QUICKLY CLEAR OUT BY 12Z FRIDAY AND STRONG UPPER JET WILL DRY THINGS OUT VERY QUICKLY AS LOW EXITS FROM THE AREA. LONG TERM (SATURDAY NIGHT THROUGH WEDNESDAY)... HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH SATURDAY. A DRY COLD FRONT WILL PUSH THROUGH THE AREA ON SATURDAY AND ZONAL FLOW WILL ALLOW FOR SOME MODERATION OF TEMPERATURES THROUGH THE PERIOD WITH BELOW NORMAL PRECIP EXPECTED. AVIATION... LOW PRESSURE IN THE GULF OF MEXICO WILL MOVE NORTHEAST TODAY...ALONG THE SOUTHEAST COAST TONIGHT THEN RAPIDLY NORTHEAST FRIDAY. ISENTROPIC LIFT IN THE LOWER LEVELS WILL INCREASE DURING THE DAY AND STRENGTHEN TONIGHT. MAY SEE SOME LOW LEVEL WIND SHEAR THIS AFTERNOON AND EVENING AS SELY LOW LEVEL JET...30KTS PLUS...BECOMES SLY WITH SFC WINDS NELY AROUND 10 KTS. EXPECTING PATCHES OF LIGHT RAIN THIS MORNING BECOMING WIDESPREAD LATE AFTERNOON AND CONTINUING OVERNIGHT. CIGS/VSBYS GRADUALLY LOWERING TO IFR AROUND 0000Z AS RAINFALL BECOMES HEAVY AT TIMES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 05 sc AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 815 PM MST THU DEC 8 2005 .DISCUSSION...CURRENT SURFACE MAP PLACES TROF/WARM FRONT OVER WESTERN DAKOTAS. UPPER LEVEL SHORTWAVE DROPPING ACROSS WESTERN WYOMING. 00Z RUC/NAM SHOWS BEST LIFT TO BE MOVING INTO THE AREA THIS EVENING...BUT VERY LITTLE SHOWING UP ON THE AREA RADARS. MID LEVEL CLOUDS ALREADY MOVING OUT OF NORTHWEST SOUTH DAKOTA/SOUTHEAST MONTANA...WITH AREA OF STRATUS MOVING SOUTH. WILL TRIM BACK POPS FOR THE REMAINDER OF THE NIGHT. BEST CHANCE OF SNOW SHOWERS WILL BE ACROSS THE NORTHERN BLACK HILLS. TEMPERATURES ACROSS EASTERN FORECAST AREA NEAR FORECAST LOWS. WITH WINDS SHIFTING TO WESTERLY COMPONENT AND CLOUDS INCREASING...TEMPERATURES SHOULD REBOUND SLIGHTLY OVER THE REMAINDER OF THE NIGHT. && .AVIATION...AREA OF MVFR CEILINGS WILL SPREAD ACROSS PORTIONS OF NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA OVERNIGHT. A FEW SNOW SHOWERS ARE POSSIBLE ACROSS THE BLACK HILLS AND NORTHEAST WYOMING THROUGH MIDNIGHT. && .UNR...WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 931 AM CST THU DEC 8 2005 .DISCUSSION...AREAS OF FOG WILL CONTINUE TO AFFECT AREAS IN THE NORTHEAST THROUGH 11 AM...WITH SOME AREAS COMING IN WITH VISIBILITIES AT 1/4 MI. UPDATED GRIDS FOR LINGERING FOG...AND FOR HIGHS. WARMER AIR ALOFT MOVES INTO THE AREA TODAY...AND WITH SOME MIXING FROM SOUTHERLY WINDS EXPECTED...BELIEVE TEMPS WILL RISE INTO THE 10-15 DEGREE RANGE AFTER COLD LOWS IN SOME SPOTS. NEW NAM12 AND RUC HAVE COME COOLER FOR TODAY...BUT SEEM TOO COLD. LOWERED HIGHS A FEW DEGREES. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ KNUTSVIG sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MORRISTOWN TN 856 PM EST THU DEC 8 2005 .DISCUSSION... OBSERVED TEMPERATURES ACROSS THE AREA HAVE BEEN HOLDING NEARLY STEADY IN THE UPPER 30S TO MID 40S. THIS IS ABOUT 5 TO 10 DEGREES WARMER THAN FORECAST. DEWPOINTS ARE ALSO HIGH...MID 30S TO LOWER 40S. THUS THE WET BULB ZERO DEGREE ISOTHERM IS WELL OUT OF OUR AREA...ELIMINATING ANY POSSIBILITY OF FREEZING RAIN. TEMPS WILL NOT DROP UNTIL A COLD FRONT NOW NEAR NASHVILLE PASSES THROUGH. BY THIS TIME MOST OF THE PRECIPITATION WILL HAVE ENDED. RUC SHOWS VERY DRY AIR MOVING IN FROM AROUND 850 MB AND HIGHER IN THE PLATEAU AROUND 06Z AND IN THE EASTERN MOUNTAINS AROUND 09Z. THE KMRX VWP DOES SHOW THAT WINDS ARE NOW BACKING WITH HEIGHT...INDICATING THAT COLD ADVECTION HAS BEGUN ALOFT...AND ERODING THE WARM NOSE ALOFT. BUT GIVEN WARM TEMPS SURFACE COOLING WILL BE SLOW UNTIL THE FROPA. THE WINTER WEATHER ADVISORY WILL BE DROPPED FOR THE TN PLATEAU COUNTIES AND LEE...SCOTT...AND WISE COUNTIES IN VA. HIGHER ELEVATIONS IN SW VA AND NE TN STILL HAVE THE POTENTIAL TO SEE SOME ACCUMULATION...SO WILL KEEP THE ADVISORY GOING THERE. SPS WILL BE UPDATED TO SHIFT EMPHASIS TO BLACK ICE ACROSS THE AREA IN THE MORNING...AND MENTION A POSSIBLE DUSTING OF SNOW FROM KNOXVILLE NORTH AND IN THE MOUNTAINS. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...WIND ADVISORY UNTIL 5 AM FRIDAY FOR THE FOLLOWING ZONES: CHEROKEE...AND CLAY. TN...WIND ADVISORY UNTIL 5 AM FRIDAY FOR THE FOLLOWING ZONES: BLOUNT SMOKY MOUNTAINS...COCKE SMOKY MOUNTAINS...JOHNSON...SEVIER SMOKY MOUNTAINS...SOUTHEAST CARTER...SOUTHEAST GREENE... SOUTHEAST MONROE...AND UNICOI. WINTER WEATHER ADVISORY UNTIL 7 AM FRIDAY FOR THE FOLLOWING ZONES: JOHNSON...SOUTHEAST CARTER...SOUTHEAST GREENE...AND UNICOI. VA...WINTER WEATHER ADVISORY UNTIL 7 AM FRIDAY FOR THE FOLLOWING ZONES: RUSSELL...AND WASHINGTON. && $$ DGS tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 328 PM CST THU DEC 8 2005 .UPDATE... ISSUED SNOW ADVISORY FOR FAR SOUTHEAST WISCONSIN. DISCUSSION...FORECAST FOCUS IS ON SHORTWAVE MOVING ACROSS IL/S WI EARLY TONIGHT. MODELS ARE IN FAIR AGREEMENT WITH THIS EVENT. SPECIFIC HUMIDITY UP TO 2 G/KG AT 850 MB. AN AVERAGE RATIO OF 13 TO 1 IS EXPECTED. HPC...COBB TECHNIQUE INDICATE BETWEEN 2 AND 4.5 INCHES OF ACCUMULATION...WITH THE 4.5 INCH TOTALS IN THE FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. WATER VAPOR AND RUC SHOWS UPPER LOW OVER S IA WITH SOME INDICATIONS IT MAY TRACK A BIT FARTHER N. MODERATE UPPER DIFLUENCE/DIVERGENCE CAUSING RADAR RETURNS TO BLOSSOM THIS AFTERNOON. WILL GO WITH A 3 TO 5 INCH TOTAL IN THE FAR SOUTHEAST WITH A SNOW ADVISORY. CYCLONIC CIRCULATION FROM UPPER LOW MAY STILL GENERATE LIGHT SNOW FLURRIES UNTIL AROUND 06 IN THE FAR SOUTHEAST. QUIET WEATHER FRIDAY WITH WEAK RIDGE BUILDING EARLY FRIDAY THEN NEXT SHORTWAVE DROPS TO THE SOUTH FRIDAY NIGHT. NEXT UPSTREAM TROF TO AFFECT S WI SATURDAY WITH LIGHT SNOW OR FLURRIES. A SERIES OF WEAK SHORTWAVES MOVE THROUGH THE UPPER TROF SUNDAY AND MONDAY. TIMING OF WHAT LITTLE DYNAMICS ARE FORECAST TO BE AVAILABLE IS UNCERTAIN. MOISTURE IS ALSO LIMITED. WILL MENTION ONLY SMALL POPS THROUGH THE PERIOD WITH LITTLE ACCUMULATION. UPPER RIDGE THEN BUILDS TUESDAY AND WEDNESDAY BEFORE ANOTHER SHORTWAVE APPROACHES. && .MKX WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ070-WIZ071- WIZ072. && $$ HENTZ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 145 PM CST THU DEC 8 2005 .DISCUSSION...FORECAST FOCUS IS ON SHORTWAVE MOVING ACROSS IL/S WI EARLY TONIGHT. MODELS ARE IN FAIR AGREEMENT WITH THIS EVENT. SPECIFIC HUMIDITY UP TO 2 G/KG AT 850 MB. AN AVERAGE RATIO OF 13 TO 1 IS EXPECTED. HPC...COBB TECHNIQUE INDICATE BETWEEN 2 AND 4.5 INCHES OF ACCUMULATION...WITH THE 4.5 INCH TOTALS IN THE FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. WATER VAPOR AND RUC SHOWS UPPER LOW OVER S IA WITH SOME INDICATIONS IT MAY TRACK A BIT FARTHER N. MODERATE UPPER DIFLUENCE/DIVERGENCE CAUSING RADAR RETURNS TO BLOSSOM THIS AFTERNOON. SOME CONCERN WE MAY NEED TO GO WITH A 3 TO 5 INCH TOTAL IN THE FAR SOUTHEAST WITH A SNOW ADVISORY. WILL WAIT FOR 18Z NAM FOR A FINAL DECISION. EARLIER UPDATE WILL WORK WELL FOR NOW. CYCLONIC CIRCULATION FROM UPPER LOW MAY STILL GENERATE LIGHT SNOW FLURRIES UNTIL AROUND 06 IN THE FAR SOUTHEAST. QUIET WEATHER FRIDAY WITH WEAK RIDGE BUILDING EARLY FRIDAY THEN NEXT SHORTWAVE DROPS TO THE SOUTH FRIDAY NIGHT. NEXT UPSTREAM TROF TO AFFECT S WI SATURDAY WITH LIGHT SNOW OR FLURRIES. A SERIES OF WEAK SHORTWAVES MOVE THROUGH THE UPPER TROF SUNDAY AND MONDAY. TIMING OF WHAT LITTLE DYNAMICS ARE FORECAST TO BE AVAILABLE IS UNCERTAIN. MOISTURE IS ALSO LIMITED. WILL MENTION ONLY SMALL POPS THROUGH THE PERIOD WITH LITTLE ACCUMULATION. UPPER RIDGE THEN BUILDS TUESDAY AND WEDNESDAY BEFORE ANOTHER SHORTWAVE APPROACHES. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HENTZ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 729 AM CST THU DEC 8 2005 .UPDATE...LATEST RUC AND NAM HAD CONDENSATION PRESSURE DEFICITS OF 50MB OR LESS FURTHER NORTHWARD TODAY. THUS...TRENDED SNOW A BIT FURTHER NORTH THAN IN THE CURRENT DATA BASE. ZONES WERE UPDATED TO REFLECT THIS THINKING AT 1322Z. OTHERWISE...OVERALL FORECAST SCENARIO WITH REGARDS TO SNOWFALL AND AMOUNTS APPEARS REASONABLE. && THOMPSON .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH SATURDAY MAIN FOCUS THIS FORECAST WILL BE SNOW CHANCES/AMOUNTS TODAY THROUGH THIS EVENING. TEMPERATURES AND SNOW CHANCES FRIDAY NIGHT THROUGH SATURDAY ARE ALSO A CONCERN. AT 2 AM...SURFACE ANALYSIS SHOWED A A RIDGE OF HIGH PRESSURE EXTENDING FROM EASTERN DAKOTAS SOUTHEAST THROUGH WI. MEANWHILE...A VIGOROUS UPPER LEVEL LOW WAS MOVING SLOWLY EAST FROM EASTERN NEBRASKA. RADAR MOSAIC AND SURFACE OBSERVATIONS SHOWING LIGHT SNOW FALLING IN ADVANCE OF THIS UPPER LOW ALONG AND SOUTH OF A LINE FROM KFSD ND-KCAV AND KCID IA. THE LEADING EDGE OF THIS SNOW AREA WAS MOVING NORTHWARD AT 15 TO 20 MILES AN HOUR TOWARD SOUTHERN PORTIONS OF THE FORECAST AREA. 00Z 08DEC05 MODEL INITIALIZATION SHOWS GFS QPF PROG WITH THE EDGE AT 06Z WHEN COMPARED AGAINST REAL-TIME RADAR/SURFACE OBS. NAM IS A BIT DRY GIVEN THE STRONG FORCING SIGNALS ASSOCIATED WITH THE UPPER LOW OVER EASTERN NEBRASKA. WILL LEAN HEAVILY TOWARD THE GFS WITH HANDLING OF QPF ASSOCIATED WITH THIS SYSTEM. UPPER LOW WILL CONTINUE TO CHURN EASTWARD ACROSS IA TODAY AND NORTHERN IL BY THIS EVENING. THIS PUTS SOUTHERN PORTION OF FORECAST AREA ON NORTHERN PERIPHERY OF STRONG ISENTROPIC LIFT (AS EVIDENCED ON THE 275K SURFACE) AND STRONG/DEEP LAYERED QG-CONVERGENCE. RAPID SATURATION OF THE COLUMN WILL OCCUR ACROSS THE SOUTH THIS MORNING IN STRONG FORCING. DRIER AIR ACROSS THE NORTH SOUTH SET UP A FAIRLY SHARP N TO S PRECIPITATION VS. NO PRECIPITATION GRADIENT. SNOW FALLING ACROSS IA HAD A 1:17 LIQUID-SNOW RATIO. FURTHER NORTH ACROSS OUR AREA IT WOULD BE RIGHT AROUND 1:20. BASED ON ALL THIS...HAVE BUMPED POPS UP AND TRENDED SLIGHTLY FURTHER NORTH. KEPT LINGERING POPS ACROSS THE SOUTH AND EAST EARLY THIS EVENING AS DEFORMATION BAND SNOW MAY BE SLOW TO GET OUT OF HERE. WHEN ALL IS SAID AND DONE...LOOKS LIKE 2-2.5 INCHES OF SNOW COULD FALL ACROSS PORTIONS OF GRANT COUNTY IN WI...AND CLAYTON/FAYETTE COUNTIES IN NORTHEAST IA....WITH RAPIDLY TAPERING AMOUNTS NORTH OF THIS. SNOW CHANCES SHOULD BE DONE BY 9PM AS THE UPPER LOW PULLS EAST INTO INDIANA. MODELS CONSISTENT IN SHOWING A STRONG SURFACE LOW APPROACHING THE AREA FROM CANADIAN PLAINS FRIDAY NIGHT INTO SATURDAY. STRONG ISENTROPIC UPGLIDE/WAA INDICATED ACROSS THE AREA LATE FRIDAY NIGHT IN ADVANCE OF THE COLD FRONT FROM THIS SYSTEM DROPPING THROUGH MN INTO NORTHWEST WI. WITH INCREASING CLOUDS AND WAA...TEMPERATURES WILL BE STEADY OR SLOWLY RISE THROUGH FRIDAY NIGHT. TRIED TO REFLECT THIS IN THE TEMPERATURE GRIDS. CAA AND CYCLONIC FLOW ACROSS THE AREA ON SATURDAY SHOULD GENERATE SCATTERED SNOW SHOWERS. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY ECMWF/GFS/DGEX ALL IN GOOD AGREEMENT IN KEEPING THE FORECAST AREA IN NORTHWEST FLOW THROUGH THE PERIOD. SEVERAL EMBEDDED SHORTWAVES IN THE FLOW WILL KEEP SNOW CHANCES GOING. GRIDS REFLECT THIS WELL. NO CHANGES MADE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DAS wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1225 AM EST FRI DEC 9 2005 .AVIATION... LATEST KIWX RADAR WAS SHOWING A DECREASING TREND IN THE INTENSITY OF SNOW ACRS NRN INDIANA...ALTHOUGH IT WILL CONTINUE FOR AT LEAST ANOTHER 3 TO 4 HOURS UNTIL ASSOCIATED 700 MB CLOSED LOW/DEFORMATION AXIS PIVOTS OFF TO THE NORTH AND EAST. TIGHT SFC PRESSURE GRADIENT BETWEEN SFC LOW OVER N CNTRL OHIO AND HIGH PRESSURE RIDGE OVER THE ERN PLAINS WAS CREATING WIND GUSTS IN EXCESS OF 30 KNOTS ACRS CNTRL/SRN INDIANA AND SOUTHWEST OHIO. SOME OF THESE GUSTS ARE EXPECTED AT KFWA FOR THE REMAINDER OF THE NIGHT...AND THESE GUSTS WILL HELP REDUCE VSBYS IN BLOWING SNOW. FROM 12Z-18Z...MAINLY MVFR CIGS WILL PREVAIL ACRS THE TAF SITES AS LOW LVL MOISTURE WILL BE SLOW TO PULL AWAY...BEING SUPPLEMENTED BY FETCH OFF OF LAKE MICHIGAN. A SMALL WINDOW OF OPPORTUNITY EXISTS BETWEEN 12Z AND 15Z FOR SOME LAKE EFFECT SNOW SHOWERS AT KSBN. THEREAFTER...850 MB TEMPS WARM ENOUGH AND DRIER AIR WORKS INTO THE REGION TO SHUT OFF THE LAKE EFFECT. TAF SITES SHOULD EXPERIENCE CLEARING CONDITIONS BY MID TO LATE AFTN AS AFOREMENTIONED SFC RIDGE BUILDS INTO THE OHIO VLY. && .PREVIOUS DISCUSSION... UPDATE... UPGRADE REMAINDER OF CWA TO HEAVY SNOW WARNING WITH 5-8 INCHES...MAYBE SPOT 9 INCHES IN SE CWA AS NNE-SSW MESOBANDING INDICATED KIND 88-D. 3H JETLET SAMPLED AT KILN/160 KT. FEATURE UNDERESTIMATED BY NAM12 AND RUC BY AROUND 30KTS. DEEP LAYER ASCENT ENHANCED IN REGION WHERE FAVORABLE 2-3 G/KG ON I285 SURFACE THROUGH FOR NEXT COUPLE OF HOURS. 30-35 DBZ WITH BANDS LIFTING INTO SE FA WILL ADD TO ALREADY GENERAL 4-6 INCHES. 7H LOW NOW INTO NORTH CENTRAL IL NEAR KPNT HAVE EXTENDED CAT SNOW POPS A FEW MORE HOURS WITH RAPID TAPER BY DAYBREAK. UPDATE... (810 PM) NORTHERN THIRD UPGRADED TO HEAVY SNOW WARNING. AMOUNTS AT LEAST IN NORTHWEST PART OF CWA IN 3-5 INCH RANGE ALREADY AND SNWFL RATES OF 1.0-2.0 INCHES PER HOUR TO CONTINUE THROUGH 04Z. BAND PIVOT POINT IN EXTREME NW INDIANA ATTM HEIGHTENING AMOUNTS THERE. TROWAL/I285 ISENT LIFT WITH 2-3G/KG TAP GENERATING MODERATE TO HEAVY BANDS DESPITE WEAK SURFACE REFLECTION THOUGH BEGINNING TO DEEPEN MORE ACROSS CENTRAL INDIANA WITH GREATER THAN 4MB/3HR FALLS INTO SOUTHERN CWA. DEFORMATION ZONE/7H TRACK SHOULD GIVE NORTHERN AREAS THE HIGHEST TOTALS AND HAVE UPPED TOTALS TO 6-9 WITH 4-7 IN REMAINDER OF ADVISORY AREA. SHORT TERM... TONIGHT AND FRIDAY... LATEST KIWX RADAR...AND RECENT OBSERVER REPORTS CONFIRM...LEADING EDGE OF SNOW NOW MOVING INTO SW CWA. MAIN FCST PROBLEM WAS IF ANY UPGRADE TO ADVISORY NEEDED. WATER VAPOR LOOP SHOWING UPPER LOW MOVING ALONG IA/MO BORDER WITH PROFILER DATA INDICATING 130KT UPPER JET ROUNDING BASE OF THE TROUGH IN SOUTHERN MO. MODELS IN GOOD AGREEMENT WITH TRACK OF THIS SYSTEM TONIGHT. VERY FAVORABLE DYNAMICS COME IN TO PLACE OVER THE CWA THIS EVENING...MAIN LIMITING FACTOR WILL BE PROGRESSIVE NATURE OF THIS SYSTEM AND RESULTING DURATION OF SNOW EVENT. SNOW THAT IS CURRENTLY ENTERING CWA ASSOCIATED WITH 850MB WAA. BY 00Z...700MB LOW EXPECTING TO BE ENTERING WEST CENTRAL ILLINOIS PLACING OUR AREA IN FAVORABLE DEFORMATION ZONE FOR ANOTHER ROUND OF SNOW IN CENTRAL AND NORTHERN PORTIONS OF THE CWA. BOTH GFS AND NAM INDICATING AREAS OF K INDEX AROUND 15 THIS EVENING SO BRIEF PERIODS OF HEAVY SNOW POSSIBLE. CROSS SECTIONS OVER NORTHERN CWA ALSO INDICATING GOOD PLACEMENT OF OMEGA IN RELATION TO FAVORABLE TEMP RANGE FOR DENDRITIC SNOW GROWTH. HOWEVER...OVERALL PATTERN TO REMAIN PROGRESSIVE AS NEXT UPSTREAM SHORT WAVE ALREADY DROPPING DOWN INTO NORTHERN PLAINS SO RESULT SHOULD BE A STRONG BUT SHORT LIVED SNOW EVENT...SO CURRENT FCST OF GENERALLY 4-7 NORTH 3-6 INCHES SOUTHEAST SEEMS REASONABLE SO WILL OPT TO CONTINUE ADVISORY AND HOLD OFF ON UPGRADE TO WARNING. UPPER LOW EXPECTED TO TRACK RIGHT OVER THE CWA BY 06Z...THIS SHOULD ACT TO SHIFT BEST DYNAMICS TO OUR NORTH AND EAST AFTER MIDNIGHT. MAY SEE SOME ADDITIONAL LAKE ENHANCEMENT AS SYSTEM EXITS WITH 925MB LOW OVER SE LAKE MICHIGAN AT 06Z. QUICK TRANSITION TO LAKE EFFECT AS DECENT NORTHERLY FETCH DEVELOPS WITH INVERSION HEIGHTS AROUND 4KFT AND MODEST DELTA T AROUND 15. SHOULD BE SHORT LIVED HOWEVER AS FLOW BECOMES WEST/SOUTHWEST BY 18Z...SO NOT EXPECTING MUCH MORE THAN AN ADDITIONAL INCH OR SO IN THE LAKE EFFECT AREA. LONG TERM... ACTIVE PATTERN WITH BELOW NORMAL TEMPERATURES EXPECTED TO CONTINUE THROUGH MOST OF THE LONG TERM PERIOD. ON THE LARGE SCALE...SEVERAL STRONG SHORT WAVE TROUGHS SEEN IN WATER VAPOR UPSTREAM...RIDING OVER TOP OF WESTERN RIDGE. FIRST SHORT WAVE TO IMPACT LONG TERM PERIODS IS SEEN IN WATER VAPOR DIGGING INTO MONTANA AND WYOMING. 12Z MODELS IN GOOD AGREEMENT DIGGING THIS WAVE INTO THE OH AND TN VALLEY REGION BY SATURDAY. DESPITE VIGOROUS LOOK IN THE 500MB HEIGHT AND VORT FIELDS...MOISTURE ASSOCIATED WITH THIS FEATURE IS LACKING AND CURRENT TRACK WOULD PLACE IT TOO FAR SOUTH TO HAVE MUCH IMPACT ON OUR FORECAST AREA. NEXT SHORT WAVE TO HAVE MORE OF AN IMPACT AS IT APPEARS TO HAVE MORE MOISTURE ASSOCIATED WITH IT. THIS WAVE IS CURRENTLY TOPPING THE WESTERN RIDGE AND WILL QUICKLY FOLLOW FIRST WAVE...BRINGING A REINFORCEMENT OF COLD AIR AND HELPING CARVE OUT DEEP EASTERN CONUS TROUGH. NUMEROUS WEAKER SHORT WAVES WILL THEN MOVE THROUGH THIS LONG WAVE TROUGH WITH PLENTY OF MOISTURE IN PLACE FOR OFF AND ON SNOW SHOWERS. UNCERTAINTY THEN LIES IN THE DAY 6 THROUGH 8 TIME FRAME AS MODELS HAVING TROUBLE HANDLING WESTERN RIDGE AND CUTOFF LOW THAT UNDERCUTS IT AND THE PHASING OF ANOTHER SHORT WAVE COMING SOUTH OUT OF CANADA. MODELS TEND TO BE TOO PROGRESSIVE WITH NORTHERN STREAM IN SUCH CASES...AS THEY WERE LAST WEEK WITH TODAYS DEVELOPING SYSTEM. TEND TO FAVOR SOMETHING CLOSER TO 12Z GFS WHICH DIGS SHORT WAVE ENERGY FURTHER SOUTH INTO LOW LIFTING OUT OF SOUTHWEST. THIS WOULD RESULT IN A STRONGER AND SLOWER SOLUTION. HAVE OPTED FOR A CHANCE OF SNOW IN THE DAY 7 TIME FRAME BUT MUCH UNCERTAINTY WITH OVERALL PATTERN BY THIS TIME. IN THE DETAILS...HAVE KEPT SATURDAY DRY WITH THE VIGOROUS SHORT WAVE DUE TO ITS POSITION WELL SOUTH OF US AND LACKING MOISTURE. LIGHT SNOW AND SNOW SHOWERS SHOULD ACCOMPANY ARCTIC FRONT SAT NIGHT SUNDAY AS 100+ 300 MB JET DIVES SOUTHEAST AND PUTS THE AREA IN LEFT FRONT REGION. POSSIBLE LAKE EFFECT SNOW SUNDAY WITH NORTHWEST FLOW AND DELTA T VALUES IN UPPER TEENS. HAVE GONE WITH SOME ACCUMS IN FAVORED LAKE EFFECT AREAS AND HIGH CHANCE POPS. THE EMBEDDED SHORT WAVES AND LINGERING MOISTURE WILL KEEP SNOW SHOWERS IN FORECAST THROUGH MONDAY NIGHT BEFORE POSSIBLE RIDGING MOVES IN TUE. KEPT TUE AND WED DRY FOR NOW AS RIDING TRIES TO HOLD AHEAD OF DIGGING UPSTREAM WAVE. ADDED POPS TO DAY 7 FOR THE POSSIBILITY OF THIS UPSTREAM WAVE MOVING IN. LOWERED TEMPERATURES MOST PERIODS...ESPECIALLY SUNDAY INTO TUE WITH LARGE SCALE AMPLIFIED TROUGH OVER AREA. ANY CLEARING DURING NIGHTTIME HOURS WILL LEAD TO MORE SINGLE DIGIT OR COLDER LOWS GIVEN EXPECTED SNOW COVER. TOO DIFFICULT TO NAIL DOWN RIGHT NOW WITH THE SHORT WAVE ENERGY AND TIMING OF ANY CLEARING AND DECOUPLING. BEST CHANCE MAY BE FRIDAY NIGHT BETWEEN WAVES WHEN MODELS CLEAR OUT RH MOST LEVELS AHEAD OF UPSTREAM SHORT WAVE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR INZ017-INZ018. HEAVY SNOW WARNING UNTIL 4 AM EST /3 AM CST/ FRIDAY FOR INZ003- INZ004-INZ005-INZ006-INZ007-INZ008-INZ009-INZ012-INZ014- INZ016. HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR INZ013-INZ015- INZ020-INZ022-INZ023-INZ024-INZ025-INZ026-INZ027-INZ032- INZ033-INZ034. MI...HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR MIZ077-MIZ078- MIZ079-MIZ080-MIZ081. OH...HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR OHZ004-OHZ005- OHZ015-OHZ016-OHZ024-OHZ025. HEAVY SNOW WARNING UNTIL 4 AM EST FRIDAY FOR OHZ001-OHZ002. LM...NONE. && $$ AVIATION...HICKMAN SHORT TERM/UPDATE...MURPHY LONG TERM....14 in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 225 AM EST FRI DEC 9 2005 .SHORT TERM (TODAY-TONIGHT)... ...VERY COLD OVER NEXT 24 HOURS... IN THE WAKE OF POTENT UPPER TROF BARRELING EASTWARD OVER IN/OH... WESTERLIES HAVE BEEN GUSTY OVER THE CWA...G25-30KTS COMMON DURING THE PAST FEW HOURS. WIND CHILLS INTO SINGLE DIGITS TO NEAR ZERO THROUGH THE PRE-DAWN HOURS. GRADIENT LOOKS TO RELAX CONSIDERABLY THIS MORNING PER BUFKIT SOUNDINGS AS SFC HIGH MOVES INTO THE REGION. THERE WERE SOME BLOWING SNOW ISSUES OVER INDIANA EARLIER...THOUGH WITH WINDS SETTLING DOWN THIS WILL BECOME LESS OF AN ISSUE FOR SRN INDIANA. LOW STRATUS REMAINS OVER MUCH OF THE CWA AS OF 06 UTC...SOME BREAKS ALONG/WEST OF I-65. EMBEDDED WITHIN...A RATHER PERSISTENT BAND OF -SHSN/FLURRIES HAS DEVELOPED FROM BRECKINRIDGE COUNTY OVER INTO THE FTK/LOU/FFT AREAS...PRODUCING SOME TRACE ACCUMULATIONS. BUFKIT SOUNDINGS INDICATE SHALLOW LAYER OF STEEP LAPSE RATES INTO THE -10 TO -15C LEVEL PERSISTING INTO THE MORNING HOURS...SO WILL CONTINUE TO MENTION SCT LIGHT SNOW SHOWERS OR FLURRIES. THERE HAVE BEEN REPORTS OF ACCIDENTS DUE TO REFREEZE FROM YESTERDAYS PCPN... SOMETHING THAT MORNING COMMUTERS WILL HAVE TO KEEP IN MIND... ESPECIALLY IN PARKING LOTS AND UNTREATED SURFACES. CLOUD FCST WILL BE CHALLENGING. RUC/NAM 925MB RH FIELDS DEPICT THE CURRENT CLOUD DISTRIBUTION WELL...AND INDICATE CLEARING FROM SW-NE THROUGHOUT THE DAY WHICH SEEMS REASONABLE...GIVEN RELATIVELY SHALLOW NATURE OF THE MOISTURE. THOUGH WITH BOUNDARY LAYER WINDS SWITCHING FROM W TO N/NW TODAY...THAT MAY SLOW THE PROGRESSION OF CLEARING SUCH THAT PARTS OF SE IND INTO LEX/BLUEGRASS COUNTIES MAY STAY CLOUDY LONGER. TEMPERATURES ARE ANOTHER CONCERN. WITH 850MB TEMPS NEAR -10C PER RUC ANALYSIS AND SDF ACARS SOUNDINGS...A VERY COLD DAY IS IN STORE ESPECIALLY AREAS THAT WOULD HAVE MORE CLOUD COVER. LEANED TOWARD RAW NAM/MOS NUMBERS. SNOWCOVER OVER SRN IND WILL HAVE A DOWNWARD INFLUENCE ON TEMPS TONIGHT...THOUGH THERE COULD BE SOME HIGH CLOUDS AFTER MIDNIGHT AHEAD OF ANOTHER UPPER SHORTWAVE APPROACHING. WON'T GO AS COLD AS RAW NAM DATA TONIGHT...BUT SOME UPPER SINGLE DIGIT READINGS POSSIBLE IN SRN IND...WITH LOW/MIDDLE TEENS ELSEWHERE IN THE CWA. CS .LONG TERM (SATURDAY-THURSDAY)... .SATURDAY... EXPECT A TRANQUIL DAY AS LOWER OHIO VALLEY WILL REMAIN BETWEEN SYSTEMS. HIGH PRESSURE ACROSS THE SOUTHEASTERN STATES WILL PROVIDE SUNNY SKIES WITH LIGHT WINDS...ALBEIT WITH STILL CHILLY TEMPERATURES. LIGHT WINDS IN THE MORNING WILL BECOME SOUTHWEST IN THE AFTERNOON AS WINDS INCREASE A BIT AHEAD OF A SURFACE TROUGH MOVING SOUTH ACROSS THE UPPER MIDWEST. .SUNDAY... AS A REX BLOCK SHARPENS ACROSS THE WEST COAST...TROUGH WILL AMPLIFY ALONG THE MISSISSIPPI VALLEY AS JET STREAM ENERGY DROPS SOUTHWARD ACROSS CENTRAL US. SURFACE TROUGH ASSOCIATED WITH LOW PRESSURE MOVING ACROSS THE GREAT LAKES WILL PUSH A REINFORCING COLD SURGE DURING THE DAY ON SUNDAY. LOW LEVEL MOISTURE WILL INCREASE SUNDAY AND CANNOT RULE OUT CHANCE OF LIGHT SNOW DURING THE DAY AND SUNDAY NIGHT. CHANCES OF SNOW MAY CONTINUE THROUGH EARLY MONDAY AS ISENTROPIC LIFT INCREASES ACROSS AN ELEVATED FRONT EXPECTED TO DEVELOP ACROSS KENTUCKY. .TUESDAY THROUGH THURSDAY... THIS PERIOD MAY BE THE START OF AN UPPER AIR TRANSITIONAL PERIOD AS REX BLOCK ACROSS WEST COAST BREAKS DOWN DUE TO WESTERLIES UNDERCUTTING THE RIDGE. TEMPERATURES ACROSS THE LOWER OHIO VALLEY...RUNNING AROUND 13 DEGREES BELOW NORMAL FOR THE MONTH OF DEC SO FAR...MAY MODERATE AS PERSISTENT COLD TROUGH EASES AND MOVES EAST TOWARDS NEW ENGLAND. WITH A SPLIT FLOW PATTERN MOVING EAST ACROSS THE PLAINS...THE LOWER OHIO VALLEY LOOKS STORM FREE THIS PERIOD. WILL KEEP JUST A CHANCE OF PRECIP IN FORECAST WEDNESDAY AS A WEAK DISTURBANCE MOVES ACROSS UPPER OHIO VALLEY. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TAUNTON MA 500 AM EST FRI DEC 9 2005 .SHORT TERM (TODAY)... MESO DISCUSSION AND 06Z MODEL UPDATE... SNOW HAS MADE IT INTO NYC AND JUST STARTED IN HARTFORD AS WELL AS BERKSHIRES AND MONADNOCKS. KBOX RADAR SHOWS AN INITIAL BAND OF SNOW FROM MANCHESTER TO CAPE ANN AND OFFSHORE WHICH FOR MOST PART IS ALOFT...BUT IT IS GIVING A QUICK SHOT OF SNOW TO SOUTHERN NH. YOU CAN SEE THE DRY AIR AT LOWER LEVELS VERY WELL ON KBOX RADAR TOO... COVERING MUCH OF EASTERN MA AND RI. THIS WILL SLOWLY MOISTEN DURING NEXT COUPLE OF HOURS AND WE EXPECT SNOW TO REACH WORCESTER AND PROVIDENCE BY 7 AM AND BOSTON AROUND 8 AM OR SO. MODELS ARE TRENDING CLOSER WITH EACH RUN. 06Z NAM IS NOW A BIT FARTHER S WITH ITS LOW TRACK...NOW FROM MONTAUK POINT TO CAPE COD BAY WITH GFS HOLDING FIRM ON ITS TRACK S OF NANTUCKET. OTHER MESOSCALE MODELS INCLUDING 06Z RUC AND 06Z 10KM BOX ETA PREFER A TRACK CLOSER TO NAM...BUT THIS JUST SEEMS A BIT TOO FAR N TO US. ONE THING WE NOTICED IS NAM IS STILL A BIT SLOWER...AND BRINGS BEST LIFT INTO SOUTHERN NEW ENGLAND FROM MID MORNING INTO MID AFTERNOON...SO WE ARE STILL ON TARGET FOR 1-2"/HR SNOWFALL RATES...ESPECIALLY FOR HARTFORD TO WORCESTER AND LAWRENCE CORRIDOR WHERE SNOWFLAKE PRODUCTION WILL BE MAXIMIZED. WE HAVE SOME CONCERN THAT THIS STRONG LIFT MAY BE ABLE TO COMPENSATE ENOUGH FOR MARGINALLY WARM LOW LEVEL TEMPERATURES IN BOSTON AREA. IT STILL APPEARS WARM ENOUGH FOR A CHANGE TO RAIN IN PROVIDENCE AND SE MA. BOSTON MAY VERY WELL END UP SEEING MORE OF A MIX AS OPPOSED TO A CHANGE TO RAIN SHOULD NAM VERIFY...BUT A PROLONGED SE WIND USUALLY KILLS THE SNOWFLAKES IN BOSTON. ONE THING THAT HAS BEEN IMPRESSIVE SO FAR IS WHAT'S BEEN GOING ON UPSTREAM ACROSS MID ATLANTIC...ESPECIALLY FROM WASHINGTON DC INTO PA WHERE THERE HAVE BEEN MANY REPORTS OF 1-2"/HR SNOWFALL RATES AND EVEN THUNDER! THIS SHOULD ALL COME OUR WAY LATER THIS MORNING AND EARLY THIS AFTERNOON. JWD && .PREVIOUS DISCUSSION... (ISSUED 335 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH TONIGHT)... WE ARE KEEPING ALL WARNINGS AND ADVISORIES IN PLACE FOR SNOW TODAY... BUT WILL TRIM AMOUNTS DOWN SLIGHTLY NEAR I-95 CORRIDOR WHICH SHOULD SERVE AS OUR TRANSITION ZONE. TOTALS ACROSS INTERIOR LOOK GOOD. WE WILL ALSO UPGRADE THE HIGH WIND WATCH FOR CAPE COD AND THE ISLANDS TO A HIGH WIND WARNING. LEADING EDGE OF SNOW IS CURRENTLY WORKING THROUGH CENTRAL NY AND EASTERN PA...NOTE HOW QUICKLY VISIBILITIES DROP TO 1/2SM OR LESS AS SNOW BEGINS! ALTHOUGH WE HAVE PLENTY OF LOW LEVEL DRY AIR TO OVERCOME...IT WON'T TAKE LONG TO SATURATE THE COLUMN WITH SUCH A POTENT SYSTEM ON OUR DOORSTEP. WE EXPECT SNOW TO BEGIN IN CT VALLEY AROUND SUNRISE (PROBABLY 6 AM) AND QUICKLY HEAD TO E MA COAST DURING MORNING RUSH HOUR (8-9 AM)...PLUS/MINUS AN HOUR OR TWO. 00Z NAM STILL FARTHEST N OF MODELS THIS MORNING...BUT 00Z GFS CONTINUES ITS TREND OF EDGING FARTHER N WITH EACH RUN...NOW TAKING SECONDARY LOW JUST SE OF NANTUCKET. IT AGREES WELL WITH ITS 00Z ENSEMBLE MEMBERS AND MATCHES WELL WITH ENSEMBLE MEAN. WE ALSO LOOKED AT 00Z NGM...AND IT ACTUALLY PRESENTS A DECENT SOLUTION. ITS SURFACE LOW IS SIMILAR TO GFS...BUT WE LIKE ITS 24HR QPF OF 0.50 TO 1.00" WHICH IS MUCH LOWER THAN NAM/GFS. OFTEN WE LIKE TO SEE NGM ON BOARD WITH SIGNIFICANT QPF BEFORE JUMPING ON A BIG EVENT...AND SINCE WE HAVE HAD DOUBTS AS TO EXCESSIVE QPF AMOUNTS SHOWN ON PAST RUNS OF NAM/GFS THIS LEADS MORE CREDENCE TO FACT THAT THOSE TWO MODELS ARE PROBABLY OVERDOING IT...ESPECIALLY GIVEN PROGRESSIVE NATURE OF THIS SYSTEM AS UPPER LOW DOES NOT CUTOFF UNTIL IT PASSES CAPE COD. SO IF WE ADJUST OUR TRACK TO JUST INSIDE 40/70 BENCHMARK...IT WOULD PLACE HEAVIEST PRECIPITATION ACROSS INTERIOR FROM NORTHERN CT INTO CENTRAL/INTERIOR NE MA AND SW NH. CROSS SECTIONS STILL SHOW TREMENDOUS MID LEVEL FRONTOGENESIS IN THIS REGION WITH EXCELLENT POTENTIAL FOR SLANTWISE CONVECTION/MESOSCALE BANDING. THIS IS ALSO ZONE OF MAXIMUM SNOW GROWTH. ONLY LIMITING FACTOR TO MAKING THIS A BLOCKBUSTER EVENT CONTINUES TO BE SPEED OF SYSTEM...SO ALTHOUGH IT'S GOING TO SNOW HARD FOR SEVERAL HOURS FROM MID MORNING INTO EARLY AFTERNOON WITH SNOWFALL RATES OF 2" PER HOUR...IT SHOULD NOT LAST LONG ENOUGH TO GIVE WIDESPREAD TOTALS OVER 10". WE'LL PROBABLY GET SOME THUNDER/LIGHTNING REPORTS WITH THIS AS WELL. CLOSER TO COAST...WE NEED TO DEAL WITH PRECIPITATION TYPE AS WE HAVE NO BLOCKING HIGH TO NORTH TO KEEP COLD AIR LOCKED IN AT LOW LEVELS. WINDS SHOULD EASILY BE ABLE TO TURN SE LATER THIS MORNING...ESPECIALLY SINCE MODELS SHOW 1000 MB AGEOSTROPHIC WINDS TURNING W...NOT A GOOD SIGN TO KEEP IT COLD. GFS CROSS SECTIONS MAY BE A LITTLE TOO WARM...INDICATING A CHANGE TO RAIN AS FAR INLAND AS I-495 IN EASTERN MA AND INTO NW RI. WE THINK IT IS MORE REALISTIC THAT THE TRANSITION ZONE (IE RAIN/SNOW MIX) WILL END UP NEAR I-95 BETWEEN BOSTON AND PROVIDENCE AND PROBABLY AS FAR N AS CAPE ANN. A COMPLETE CHANGE TO RAIN SEEMS MOST LIKELY WITHIN 5-10 MILES OF THE COAST FROM BOSTON TO PLYMOUTH...THEN ACROSS SE MA NEAR TAUNTON AND INTO PROVIDENCE. THAT BEING SAID...WE WILL NUDGE STORM TOTALS DOWN SLIGHTLY IN THESE LOCATIONS. WE CURRENTLY HAVE SE MIDDLESEX AND W NORFOLK COUNTIES IN A LOW-END WINTER STORM WARNING AND THAT STILL SEEMS REASONABLE...AS WE THINK PLACES ALONG ROUTE 128 FROM WOBURN AND BELMONT TO NEWTON AND DEDHAM WILL SEE THE 4-5" AMOUNTS AND LOCATIONS FARTHER INLAND SUCH AS LEXINGTON AND ESPECIALLY MEDWAY AND BELLINGHAM WILL SEE THE 6-8" TOTALS. IN THOSE ZONES WHERE WE HAVE A WINTER WEATHER ADVISORY...WE WILL GENERALLY HAVE 2-4" TOTALS. ONE EXCEPTION TO THIS IS IN COASTAL ESSEX COUNTY MA (ZONE 7)...WHERE WE EXPECT A WIDE RANGE IN TOTALS... FROM 2" ON COASTLINE TO AS MUCH AS 7-8" NEAR NH BORDER. BUT AVERAGE IS LOW ENOUGH TO KEEP AN ADVISORY GOING THERE. HEAVIEST SNOW SHOULD SHIFT INTO MERRIMACK VALLEY EARLY THIS AFTERNOON WHILE SNOWFALL RATES DECREASE BACK ACROSS CT VALLEY. STRONGEST LIFT IS HEADING QUICKLY FOR COAST BY MID AFTERNOON...SO WE THINK MANY LOCATIONS WILL SEE IMPROVING CONDITIONS BY 3 OR 4 PM EXCEPT FOR CAPE COD AND ISLANDS. MAIN CONCERN THEN BECOMES WIND. SURFACE LOW DEEPENING RAPIDLY OFF CAPE COD WILL CAUSE A RAPID INCREASE IN WINDS THROUGHOUT ALL OF REGION...BUT ESPECIALLY NEAR COAST. IF WE TAKE GFS SOUNDINGS FOR HYANNIS AND NANTUCKET AT FACE VALUE IT SHOWS A STRONG POTENTIAL OF 50-60KT GUSTS AS THIS DEEPENING OCCURS LATE THIS AFTERNOON AND EVENING. WE THINK THIS MAY BE A LITTLE HIGH...BUT WE HAVE ENOUGH CONFIDENCE TO ISSUE HIGH WIND WARNINGS AT THIS TIME. WIND ADVISORY WILL BE KEPT IN PLACE FOR S COAST...EVEN THOUGH CONFIDENCE ON 40KT GUSTS THERE IS LESS. ADVISORIES MAY ALSO NEED TO BE ISSUED FOR E MA COASTLINE BUT RIGHT NOW WE THINK WE WILL FALL SHORT OF CRITERIA THERE. CLEARING SHOULD WORK IN RAPIDLY THIS EVENING AS CROSS SECTIONS SHOW RAPID DRYING AND STRONG SUBSIDENCE...BUT WINDS WILL ONLY DIMINISH GRADUALLY UNTIL SYSTEM PULLS FARTHER OFFSHORE. LONG TERM (SATURDAY THROUGH THURSDAY)... OVERALL COLD AIR REMAINS IN PLACE OVER REGION THROUGH AT LEAST THURSDAY. WEAK RIDGE BUILDS OVER REGION SATURDAY IN WAKE OF DEPARTING STORM. SATURDAY NIGHT HEIGHTS BEGIN TO FALL AND WINDS BACK AS CYCLONIC FLOW BEGINS TO TAKE OVER. SHORTWAVES MOVE OVERHEAD THROUGH MONDAY WHILE AT THE SURFACE A DISORGANIZED LOW PRESSURE AREA MOVES ACROSS SOUTHERN QUEBEC TOWARD THE CANADIAN MARITIMES. COLD AIR ADVECTION ACROSS REGION COULD YIELD SHOWERS OVER OUTER WATERS CLIPPING CAPE AND ISLANDS. SURFACE HIGH PRESSURE BUILDS SOUTHEAST FROM CENTRAL CANADA...AND RESULTING N TO NW WINDS OVER CAPE COULD YIELD OCEAN EFFECT SNOW SHOWERS TUESDAY AND WEDNESDAY. RIDGING THROUGH THE COLUMN BUILDS OVER NEW ENGLAND THURSDAY...THEN REGION AWAITS NEXT POTENTIAL NOREASTER FOR FRIDAY. AVIATION... VFR FOR THE MOMENT...EXCEPT FOR MVFR CEILINGS NEAR NANTUCKET WHICH WILL SPREAD ONTO S COAST EARLY THIS MORNING. CONDITIONS WILL DETERIORATE RAPIDLY THIS MORNING TO IFR AS SNOW ARRIVES (THEN TO LIFR WITHIN 2 HOURS OF THAT)...CURRENTLY TIMED INTO CT VALLEY TOWARD SUNRISE AND BEFORE MID MORNING ALONG E MA COAST. CONDITIONS WILL LIFT TO MVFR THIS AFTERNOON AS HEAVIER SNOW SHIFTS OFFSHORE...THEN WE EXPECT RAPID IMPROVEMENT TO VFR BY EARLY THIS EVENING AS LOW PULLS OFF THE COAST. MARINE... WE WILL EXPAND STORM WARNINGS THIS AFTERNOON TO INCLUDE CAPE COD BAY AND NANTUCKET SOUND...AND MAINTAIN GALE WARNINGS ELSEWHERE AS WINDS INCREASE RAPIDLY BEHIND DEPARTING LOW. THERE IS STILL SOME QUESTION AS TO HOW FAST THE LOW WILL DEEPEN...IMPACTING WIND GUST POTENTIAL... BUT IT IS MORE LIKELY IT WILL OCCUR CLOSE ENOUGH TO CAPE COD RATHER THAN FARTHER OFFSHORE. WINDS AND SEAS SLOWLY DIMINISH OVERNIGHT AS SYSTEM PULLS FARTHER AWAY. FOLLOWED WNA WAVE GUIDANCE...HOWEVER GIVEN PREVAILING WEST TO SOUTHWEST WINDS SATURDAY AND SUNDAY...INCREASED SEAS IN BUZZARDS BAY. SMALL CRAFT ADVISORY CONDITIONS EXPECTED OVER THE WEEKEND FOR OUTER WATERS AND ALONG SOUTH COAST...ALL DUE TO WIND GUSTS TO 30 KTS AND ROUGH SEAS. WINDS AND SEAS SUBSIDE MONDAY AND TUESDAY. CLIMATE... FYI...RECORD DAILY SNOWFALL TOTALS FOR TODAY ARE AS FOLLOWS... KBOS... 4.6 INCHES IN 1978 KPVD... 3.0 INCHES IN 1995 KORH... 8.0 INCHES IN 1903 KBDL... 4.2 INCHES IN 1995 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAVY SNOW WARNING FOR CTZ002>004 UNTIL 4 PM FRIDAY. MA...HEAVY SNOW WARNING FOR MAZ002>004-008>012 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR MAZ005-006-013-014-026 UNTIL 5 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR MAZ007-015>019 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR MAZ020-021 FROM 4 PM FRIDAY TO 1 AM SATURDAY. ...HIGH WIND WARNING FOR MAZ022>024 FROM 4 PM FRIDAY TO 1 AM SATURDAY. NH...HEAVY SNOW WARNING FOR NHZ011 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR NHZ012-015 UNTIL 5 PM FRIDAY. RI...HEAVY SNOW WARNING FOR RIZ001 UNTIL 4 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR RIZ002>005 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR RIZ006>008 FROM 4 PM FRIDAY TO 1 AM SATURDAY. MARINE...GALE WARNING FOR ANZ230-233>237 FROM 1 PM FRIDAY TO 1 AM SATURDAY. ...STORM WARNING FOR ANZ231-232-250-254-255 FROM 1 PM FRIDAY TO 1 AM SATURDAY. && $$ ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 425 AM EST FRI DEC 9 2005 .DISCUSSION... MAIN FCST CONCERNS ARE -SN CHANCES WITH THE SAT CLIPPER AND LES POTENTIAL IN ITS WAKE. WV IMAGERY...AND RUC ANALYSIS AND 00Z RAOBS INDICATED CONTINUATION OF PATTERN CHARACTERIZED BY RDG OVER WRN NOAM AND A TROFFING OVER THE EAST LEAVING NW FLOW FROM WRN CANADA INTO THE UPPER GRT LAKES. THE CLOSED MID LEVEL LOW TO THE SOUTH WHICH BROUGHT HEAVY SNOWS FROM KS/MO INTO THE SRN GRT LAKES HAD MOVED TO NW OHIO. UPSTREAM... COMBINATION OF 290K ISENTROPIC LIFT WITH A WEAK SHRTWV FROM WRN ONTARIO INTO ND SUPPORTED LITTLE MORE THAN AREAS OF MID CLOUDS AND A FEW FLURRIES. HEALTHY LOOKING SHRTWV WHICH WILL BE FOCUS FOR SAT WAS JUST MOVING INTO BC. AT THE SFC...LOW PRES WAS LOCATED OVER LK ERIE WHILE A RDG ASSOCIATED WITH VERY COLD ARCTIC AIR DOMINATED THE CNTRL CONUS FROM TX TO THE UPR MS VALLEY. WINDS HAD VEERED AGAIN TO WRLY WHICH HAS BROUGHT LAKE CLOUDS BACK INTO THE KEWEENAW. TODAY...EMP OF -12C NEAR THE 3K FT INVERSION...PER 04Z KCMX TAMDAR SNDG...WAS MARGINAL TO SUPPORT -SHSN ESPECIALLY GIVEN VERY DRY PRFL ON KHIB/CYQT SNDGS. HOWEVER...CANNOT RULE OUT SOME SCT FLURRIES OVER THE NRN HLF OF THE KEWEENAW AS WSW WINDS SLOWLY BACK TO SW BY THIS EVENING. OTHERWISE...MORE SUNSHINE IS EXPECTED BEFORE SCT-BKN MID CLOUDS MOVE IN...PER SATELLITE TRENDS AND MDLS 700-500 MB RH PROGS. ONLY MINOR DIFFERENCES SHOW UP WITH MDLS HANDLING OF THE BC SHRTWV AND MID LVL TROF MOVING INTO THE GRT LAKES. THE NAM REMAINED SLIGHTLY DEEPER WITH THE MID LVL TROF BY 00Z/SUN WITH THE STRONGEST SFC LOW. A BLEND OF THE GFS...SIMILAR IN TIMING TO THE NAM BUT WEAKER...AND THE SLIGHTLY SLOWER UKMET WAS PREFERRED. TONIGHT INTO SAT...AS THE CLIPPER SHRTWV AND ASSOCIATED SFC LOW MOVES FROM MANITOBA INTO WRN ONTARIO LATE TONIGHT INTO SAT ...UPR LVL DIV WITH THE RIGHT ENTRANCE OF 110 KT H3 JET INTO NRN ONTARIO ALONG WITH MODEST QVECTOR CONV WILL BRING INCREASING CHANCES FOR -SN. WHILE LITTLE SIGNIFICANT MOISTURE INFLOW IS EXPECTED INTO THE SYSTEM...THE MID/UPPER LEVEL DYNAMICS SHOULD STILL BE SUFFICIENT TO SUPPORT LIKELY POPS FOR SMALL QPF (LESS THAN A TENTH OF AN INCH). SO...EXPECT SNOWFALL AMOUNTS OF GENERALLY AN INCH OR LESS. LATE SAT INTO SUN...AS THE SFC LOW/TROF MOVES FROM SE LK SUPERIOR TOWARD LK HURON...CAA WITH 20-30 KT NRLY 950-850 MB WINDS WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW FROM WEST UPR MI INTO N CNTRL UPR MI IN THE LATE AFTERNOON AND EVENING AS H8 TEMPS DROP INTO THE -8C TO -12C RANGE BTWN 21Z-03Z. THE DEEPER MOISTURE SHOULD GRADUALLY DEPART OVERNIGHT WITH TRANSITION TO PURE LES. CYCLONIC NRLY FLOW WILL FAVOR LOCATIONS IN HIGHER TERRAIN VCNTY OF KMQT AND KIWD/ONTONAGON FOR GREATEST ACCUMULATIONS. SUCH A FLOW REGIME MAY ALSO IMPACT MID PORTION OF HOUGHTON COUNTY FROM ALSTON TO TWIN LAKES. SNOW GROWTH PARAMETERS LOOK FAVORABLE WITH SIGNIFICANT PORTION OF CONVECTIVE CLOUDS IN THE -12C TO -17C RANGE. GIVEN REMAINING UNCERTAINTY WITH EVOLUTION/TIMING OF THE SYSTEM AND ASSOCIATED WIND DIRECTIONS...WENT WITH RELATIVELY CONSERVATIVE SNOWFALL FCST AMOUNTS OF 3-7 INCHES SAT NIGHT AND 2-4 INCHES SUN IN THE FAVORED LOCATIONS. IF MDLS REMAIN CONSISTENT...A WATCH MAY BE NEEDED FOR POTENTIAL OF 8 INCHES IN BEST 12 HR WINDOW 00Z-12Z (WEST) OF 03Z-015Z(N CNTRL). 24 HOUR AMOUNTS OF 10 INCHES MAY ALSO BE POSSIBLE. LES SHOULD TAPER OFF TOWARD MIDDAY AND ESPECIALLY IN THE AFTERNOON SUNDAY AS INVERSION HGTS FALL AND SHEAR INCREASES WITH SFC RDG BUILDING INTO THE REGION. HOWEVER...THE SLOWER UKMET SCENARIO WOULD KEEP NRLY SFC-850 WINDS AND LES GOING OVER MOST OF NRN UPR MI THROUGH 00Z/MON. SUN NIGHT INTO MON...ANOTHER CLIPPER MOVING INTO THE WRN LAKES WILL BRING ANOTHER CHANCE FOR -SN. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 346 AM EST FRI DEC 9 2005 .SHORT TERM (TODAY THROUGH SUNDAY)... AS OF THIS WRITING...THE SURFACE LOW PROVIDING US WITH OUR SNOW THIS MORNING IS LOCATED OVER CENTRAL LAKE ERIE. IN ADVANCE OF THIS LOW...THE INITIAL BURST OF WARM ADVECTIVE SNOW HAS ALREADY ADVANCED CLEAR ACROSS WESTERN NY INTO LAKE ONTARIO AND THE NORTH COUNTRY...WITH A PRONOUNCED DRY SLOT NOW WORKING INTO FAR WESTERN NY/THE FINGER LAKES AS PER THE LATEST SATELLITE AND RADAR IMAGERY. BECAUSE OF THIS...MOST OF THE STEADY PCPN STILL UPSTREAM OF US IS MAINLY CONFINED TO AREAS NORTH OF THE SURFACE LOW TRACK...IN THE MID AND UPPER LEVEL DEFORMATION ZONE CURRENTLY LYING ACROSS SOUTHERN ONTARIO/LAKE HURON/LOWER MICHIGAN. THE MODELS ARE IN UNIVERSAL AGREEMENT ON THE TRACK OF THE LOW TODAY...WITH THE 00Z/06Z NAM...00Z GFS...AND RUC ALL TRACKING THE SURFACE WAVE NORTHEAST ACROSS THE NIAGARA PENINSULA/NIAGARA COUNTY...AND INTO LAKE ONTARIO THIS MORNING. SUCH A TRACK WILL KEEP THE AFOREMENTIONED AREA OF HEAVIER DEFORMATION ZONE SNOW LARGELY TO OUR NORTH AND WEST...THOUGH BY THE SAME TOKEN THERE WILL STILL LIKELY BE A 1-2 HOUR BURST OF HEAVIER SNOW AS THE TRAILING COLD FRONT WORKS ACROSS THE AREA THIS MORNING. IN TERMS OF ACCUMULATIONS TODAY...A GENERAL 1 TO 2 INCHES OF ADDITIONAL SNOW LOOK REASONABLE ACROSS THE AREA...OR A BIT LESS THAN OFFERED BY THE 00Z NAM. THE LOWEST AMOUNTS WILL LIKELY BE ACROSS THE GENESEE VALLEY AND FINGER LAKES REGION...WHILE SLIGHTLY HIGHER AMOUNTS WILL BE POSSIBLE SOUTHEAST OF THE LAKES AND EAST OF LAKE ONTARIO OWING TO LIMITED LAKE ENHANCEMENT/OROGRAPHIC EFFECTS. BECAUSE ACCUMULATIONS HAVE BEEN LIGHTER THAN EXPECTED SO FAR (GENERALLY 1-2")...AND THE FACT THAT WE ARE EXPECTING A BIT LESS SNOW TODAY COMPARED TO PREVIOUS FORECASTS...WE HAVE DECIDED TO DROP THE SNOW ADVISORY FOR ALL ZONES WITH THIS PACKAGE. THAT SAID...WHILE EVENT TOTAL SNOWFALL AMOUNTS WILL LIKELY BE LESS THAN ADVISORY CRITERIA...ANY UNTREATED ROADWAYS WILL STILL BE SNOW COVERED AND EXTREMELY SLIPPERY THIS MORNING. ANY ONGOING LAKE EFFECT ACTIVITY BEHIND THE LOW SHOULD HOLD ITS OWN UNTIL ABOUT 00Z TONIGHT SOUTHEAST OF BOTH LAKES...THEN A CRASHING INVERSION/DRYING BOUNDARY LAYER/WARMING TEMPS ALOFT WILL HELP END THE LAKE EFFECT...DURING THIS EVENING OFF OF LAKE ERIE AND BY MIDDAY SATURDAY OFF OF LAKE ONTARIO. WILL KEEP SCATTERED SNOW SHOWERS GOING THROUGH THOSE TIMES...THOUGH ACCUMULATIONS WILL BE VERY MINOR...IF ANY TONIGHT AND SATURDAY MORNING. OTHERWISE...SATURDAY SHOULD TURN OUT TO BE A PARTLY SUNNY AND DRY DAY FOR THE AREA...THOUGH IT WILL ALSO TURN OUT TO BE RATHER WINDY AS A STIFF/DEEP SOUTHWEST FLOW WILL BE IN PLACE. AS A RESULT...EVEN THOUGH HIGHS WILL BE IN THE LOWER TO MID 30S...IT WILL DEFINITELY NOT FEEL THAT WARM. FOR SATURDAY NIGHT AND SUNDAY...SURFACE LOW PRESSURE TO OUR NORTH WILL GRADUALLY EDGE SOUTHEASTWARD TOWARDS OUR AREA...EVENTUALLY SWINGING A COLD FRONT THROUGH THE AREA ON SUNDAY WITH A LIKELIHOOD OF SNOW SHOWERS. AS A RESULT...WE HAVE GRADUALLY INCREASED POPS FROM NORTHWEST TO SOUTHEAST THROUGH MID SUNDAY MORNING...THEN HAVE GONE LIKELY EVERYWHERE THE REST OF SUNDAY WITH THE COLD FROPA. ONE MESOSCALE FEATURE TO WATCH DURING THIS LATTER PERIOD: BOTH THE NAM AND GFS INDICATE THAT 850 MB TEMPS WILL DROP TO THE -8C TO -10C RANGE FOR THE LATTER HALF OF SATURDAY NIGHT...ALONG WITH A WEAKENING INVERSION/DEEPENING MOISTURE THROUGHOUT THE ATMOSPHERIC COLUMN. WITH A DEEP SOUTHWEST FLOW STILL IN PLACE...THERE IS THE POTENTIAL FOR LAKE EFFECT SNOWS TO REDEVELOP NORTHEAST OF THE LAKES LATER SATURDAY NIGHT/SUNDAY MORNING IN ADVANCE OF THE APPROACHING COLD FRONT...AND THIS WOULD AFFECT THE BUFFALO AND WATERTOWN AREAS. FOR NOW...HAVE RAISED POPS TO THE HIGH CHANCE CATEGORY FOR THESE AREAS FOR LATER SATURDAY NIGHT...BUT THIS TIME PERIOD WILL HAVE TO BE CLOSELY MONITORED BY SUBSEQUENT SHIFTS. && .LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)... THE WINTRY PATTERN WILL CONTINUE THROUGH THIS PERIOD AS A LONG WAVE UPPER TROUGH PERSISTS ACROSS EASTERN CANADA AND THE GREAT LAKES REGION. 850 MILLIBAR TEMPERATURES ARE FORECAST TO AVERAGE AROUND MINUS 15C THROUGH AT LEAST WEDNESDAY THEN JUST A LITTLE WARMER THURSDAY AS A RIDGE EDGES IN FROM THE WEST. NO MAJOR STORMS ARE FORESEEN AT THIS TIME BUT THE NORTHWEST FLOW ACROSS THE LAKES WILL LIKELY PRODUCE SOME SCATTERED LAKE EFFECT SNOWS. && .AVIATION... THE INITIAL BATCH OF WARM ADVECTION SNOW SWEPT ACROSS WESTERN NEW YORK BETWEEN 03Z AND 07Z...LOWERING CIGS AND VSBYS TO IFR AND EVEN LIFR AT TIMES. A SEMI DRY SLOT HAS FOLLOWED HOWEVER...SO CONDITIONS WILL OCCASIONALLY IMPROVE TO MVFR THROUGH 12Z IN PATCHY SNOW. KART WILL FOLLOW A SIMILAR TREND...ALBEIT DELAYED A FEW HOURS. A COLD FRONT WILL THEN SWEEP ACROSS THE REGION BETWEEN 13Z AND 17Z WITH A BURST OF SNOW AND ASSOCIATED IFR CONDITIONS...BUT ALL WILL IMPROVE TO VFR THIS AFTERNOON. WINDS WILL VEER TO SOUTH AND SOUTHWEST EARLY THIS MORNING THEN SHIFT TO WEST AND NORTHWEST FOLLOWING THE FROPA. && .MARINE... WE WILL HAVE A VERY COMPLEX WIND SCENARIO EARLY THIS MORNING AS INITIAL LOW PRESSURE NEAR DETROIT AT 06Z MOVES EAST TO LAKE ONTARIO BY 12Z AND THEN WEAKENS...GIVING WAY TO A COASTAL STORM OFF NEW JERSEY. THIS PATH WILL ALLOW WINDS TO BECOME SOUTHERLY AND INCREASE ON THE LAKE ERIE WATERS BUT THEY WILL TEND EASTERLY OVER LAKE ONTARIO. THE TRAILING COLD FRONT WILL THEN SWEEP ACROSS LAKE ERIE THIS MORNING AND LAKE ONTARIO BY EARLY AFTERNOON. WINDS WILL INCREASE INTO THE 15 TO 25 KNOT RANGE THIS AFTERNOON AND EVENING BEFORE LIGHTENING UP ONLY SLIGHTLY EARLY SATURDAY. THE WESTERLY GRADIENT WILL INCREASE AGAIN DURING SATURDAY AS DEEPENING LOW PRESSURE MOVES ACROSS NORTHERN ONTARIO. WE WILL ISSUE SMALL CRAFTS TO ACCOUNT FOR THIS SCENARIO FOR ALL NEARSHORE WATERS THROUGH 4 PM SATURDAY...BEGINNING EARLY THIS MORNING ON LAKE ERIE AND EARLY THIS AFTERNOON ON THE EASTERN SHORE OF LAKE ONTARIO AND ST. LAWRENCE RIVER. && .BUF WATCHES/WARNINGS/ADVISORIES... .NY...NONE. .MARINE....SMALL CRAFT ADVISORIES ALL NEARSHORES THROUGH SATURDAY AFTERNOON. $$ SHORT TERM...JJR LONG TERM...SAGE AVIATION/MARINE...SFM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 0108 AM EST FRI DEC 9 2005 .AVIATION (06Z-06Z)... STRONG SURFACE LOW OVER EXTREME NORTHERN OHIO WILL MOVE RAPIDLY NORTHEAST AS HIGH PRESSURE BUILDS EASTWARD ACROSS SOUTHERN OHIO...KENTUCKY AND WEST VIRGINIA. SURFACE WINDS WILL BE STRONG AND GUSTY AND BEGIN TO DISSIPATE SOUTHERN TAFS TOWARDS SUN RISE AND NORTHERN TAFS A FEW HOURS LATER. GENERALLY MVFR CONDITIONS THROUGH MUCH OF THE PERIOD EXCEPT IFR VICINITY DAY MAINLY DUE TO BLOWING SNOW. CLOUDS WILL BEGIN TO DISSIPATE AS THE DRIER LOW LEVEL AIR ASSOCIATED WITH THE WEST SOUTHWEST FLOW OF THE HIGH PRESSURE MOVES ACROSS THE AREA. EXPECT VFR CONDITIONS AFTER SUNSET WITH A LIGHT SOUTHWEST WIND. HAYDU && .PREVIOUS DISCUSSION... (ISSUED 1110 PM EST THU DEC 8 2005) SHORT TERM (REST OF TONIGHT)... HAVE UPDATED TO CLEAR HEADLINES FROM PARTS OF SOUTHERN FCST AREA. NO OTHER CHANGES PLANNED. PREVIOUS DISCUSSION... (ISSUED 928 PM EST THU DEC 8 2005) SHORT TERM (REST OF TONIGHT)... SURFACE ANALYSIS SHOWS DEEPENING LOW NEAR KMIE. WINDS ON THE BACK SIDE OF THE LOW ARE GUSTING TO 30 MPH. KILN RADAR SHOWING RETURNS BEGINNING TO DIMINISH AS BEST ISENTROPIC LIFT PULLS OFF TO THE EAST. DEFORMATION PRECIPITATION IS NOW KICKING IN AND IS A BIT LIGHTER. WARMER AIR HAS MOVED UP INTO THE TRI-STATE AND SOUTH CENTRAL OHIO OHIO AS MANY PLACES ARE AROUND TO ABOVE FREEZING. HAVE THROWN OUT AN UPDATE ALREADY TO INCREASE SNOW AMOUNTS IN THE PMH AREA. WILL THROW OUT ANOTHER UPDATE TO BRING AN END TO THE PRECIP SOONER. LATEST RUC SHOWING PRECIP ENDING QUICKLY AS DRY SLOT PUSHES EAST QUICKLY. 700 MB DEFORMATION IS MOVING THROUGH CURRENTLY AND IS WELL AHEAD OF 700 MB TROF. WILL LEAVE ALL HEADLINES WHERE THEY ARE AS SW WINDS ON THE BACKSIDE OF LOW WILL CREATE BLOWING SNOW ACROSS MUCH OF THE AREA AND MY CAUSE LIMBS AND POWER LINES TO BREAK CLOSER TO THE OHIO RIVER. NIGHT SHIFT WILL TAKE HEADLINES DOWN. TIPTON SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)... SURFACE ANALYSIS SHOWS DEEPENING DOUBLE BARREL LOW FROM NASHVILLE TO SOUTH CHAMPAIGN ILLINOIS WITH SELY FLOW ACROSS THE FORECAST AREA. SATELLITE IMAGERY SHOWS CLOUD TOPS HAVE BEEN COOLING. KILN RADAR SHOWS RETURNS HAVE BEEN INCREASING IN COVERAGE AND INTENSITY ACROSS SW FORECAST AREA. ALL MODELS ARE IN GOOD AGREEMENT WITH TAKING NORTHERN PART OF SURFACE LOW UP INTO THE GREAT LAKES AS SOUTHERN LOW JUMPS TO THE EAST COAST. SUBTLE DIFFERENCES IN LOW LEVEL THICKNESSES BETWEEN MODELS. RUC IS THE COOLEST WITH NAM AND GFS BEING A BIT WARMER. AS A RESULT OF CURRENT TRENDS AND LATEST MODEL RUNS HAVE DECREASED SNOW AMOUNTS SOUTH OF I-71 CORRIDOR PER SOME MIX OF SLEET AND FZRA. HAVE TRIED TO STICK WITH 1300 DM (1000-850 MB THICKNESS) AS A DELINEATION OF SNOW/MIX OFF RUC. THE RUC SEEMS TO HAVE THE BEST FIT WITH CURRENT CONDITIONS. REASON FOR 1300 DM WAS WITH STRONG LIFT FOR THE NEXT 6 HOURS FIGURE DIABATIC COOLING WILL HELP TO KEEP SNOW GOING AT A WARMER THICKNESSES. WILL HAVE TO MONITOR. USING GARCIA METHOD HAVE GONE WITH A 4 TO 6 INCH RANGE NORTH OF I-71. RIGHT NOW THINK MAX SNOWFALL WILL BE IN A STRIP OF 10 TO 50 MILES NORTH OF I-71 WITH 5 TO 6 INCHES BEING THE AVERAGE MEASUREMENT. GRADIENT REALLY TIGHTENS UP OVERNIGHT AS SURFACE LOW GOES FROM POSITIVE TO NEGATIVE. THIS WILL CREATE WIND GUSTS TO 30 MPH AND ALONG WITH BLOWING AND DRIFTING OF SNOW. REST OF SHORT TERM FORECAST IS BENIGN. MAV TEMPS LOOK REASONABLE CONSIDERING THE SPREAD FROM MET AND FWC. WILL GO WITH MET FOR OVERNIGHT LOWS FRIDAY NIGHT WITH FRESH SNOW PACK AND CLEAR SKIES. IT SHOULD TAKE A LITTLE WHILE FOR THE SW WIND TO MIX IN. TIPTON LONG TERM (SUNDAY THROUGH THURSDAY)... RATHER COLD UNSETTLED WX PATTERN TO CONTINUE FOR OH VLY THRU EXTENDED. SFC LO TRACKING THRU GRT LKS TO BEGIN ON SUN. TRAILING COLD FRONT WILL TRACK THRU FCST AREA DURING DAY SUN USHERING IN REINFORCING SHOT OF ARCTIC AIR TO REGION. BNDRY LYR THICKNESSES REMAIN COLD ENUF THAT ALL PCPN WILL FALL IN FORM OF -SN. AT THIS POINT...PCPN LOOKS RELATIVELY LIGHT WITH POTENTIAL FOR RESIDUAL LK EFFECT -SHSN CONTINUING FOR SUN NIGHT. A SECONDARY MID LVL S/WV EMBEDDED IN MEAN LONGWAVE TROF WILL DROP INTO FCST AREA FOR MON...AND FEEL IT IS PRUDENT TO CONTINUE WITH A CHANCE FOR -SHSN. HI PRES THEN BRIEFLY BUILDS IN FOR TUES AS WEAK MID LVL RIDGING DVLPS AHEAD OF NEXT S/WV MOVING OUT OF NRN PLAINS. THIS FEATURE WILL TRACK INTO LWR GRT LKS FOR MIDWEEK AND PROVIDE ADDL CHANCES FOR PRIMARILY -SN. THERE IS SOME MODEL DISCREPANCY REGARDING THE HANDLING OF THIS SYSTEM. HAVE TRENDED WITH CONSENSUS SOLN OF BRINGING S/WV THRU REGION ON WED...ALTHOUGH 12Z GFS NOW DELAYING THIS SYSTEM UNTIL ERLY THURS. WILL GO WITH 30 POPS WED...BUT HAVE LINGERED LO CHC POPS INTO THURS TO ACCOUNT FOR 12Z GFS SOLN. HAVE CONTINUED TREND OF KEEPING TEMPS BELOW NORMAL AND LOWER THAN MEX/MEN GUID. TAKING INTO CONSIDERATION POTENTIAL SNOW COVER FROM EVENT TONIGHT AND LARGE UPR LVL TROF FOR EASTERN CONUS AS WELL AS POTENTIAL FOR MORE CLOUDS/PCPN IN EXTENDED...COLDER TEMPS CERTAINLY APPEAR MORE PLAUSIBLE. HAVE HIGHS GENERALLY IN U20S/L30S THRU BULK OF EXTENDED PERIOD. RYAN && .ILN WATCHES/WARNINGS/ADVISORIES... OH...HEAVY SNOW WARNING FOR OHZ026-034-035-042>046-051>056-060>063- 070>072 UNTIL 6 AM FRIDAY. ...WINTER STORM WARNING FOR OHZ064-065-073-074 UNTIL 6 AM FRIDAY. KY...NONE. IN...HEAVY SNOW WARNING FOR INZ050-058-059-066 UNTIL 6 AM FRIDAY. && $$ SHORT TERM... oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 255 AM EST FRI DEC 9 2005 .SHORT TERM (TODAY THROUGH SATURDAY)... MODERATE TO HEAVY SNOW CURRENTLY FALLING OVR BULK OF CENTRAL PA IN ADVANCE OF UPPER LO ROTATING THRU OHIO VALLEY. ASSOCIATED SOUTHERLY LL JET (70KTS ON KCCX VWP)...PRODUCING A 6-8HR PERIOD OF STRONG WAA EARLY THIS AM. HOWEVER...BACK EDGE OF SNOW ALREADY ENTERING WESTERN PA. LATEST RUC ENDS STEADY SNOW BEFORE DAWN ACROSS ALL BUT SUSQ VALLEY. DESPITE THE DRY NATURE OF THE SNOW...THE SNOW:WATER RATIO MEASURED AT PSU LAST HOUR WAS 8:1...WHICH SEEMS REASONABLE GIVEN THAT MAX OMEGA OCCURRING ARND -6C. HOWEVER...PREVIOUS FCST OF A GENERAL 5-8 INCHES STILL SEEMS ON TRACK GIVEN SNOW REPORTS SO FAR AND LATEST RADAR TRENDS. UPSLOPING FLOW WILL PRODUCE LINGERING SNOW SHWRS OVR THE MTNS. HOWEVER...EXPECT LITTLE ADDITIONAL ACCUMS AS INVERSION ONLY EXPECTED ARND 800 MB. THE LARGER ISSUE WILL BE BLOWING AND DRIFTING SNOW IN OPEN AREAS LATER TODAY. AS COASTAL LOW DEVELOPS S OF NEW ENGLAND...WEST WINDS WILL BECOME STRONG BY AFTN WITH GUSTS LIKELY CLOSE TO 40MPH BASED ON MODEL SOUNDINGS. LEANED TOWARD COLDER MET READINGS TONIGHT BASED ON FRESH SNOW COVER AND DIMINISHING WINDS LATE TONIGHT AS HI PRES BUILDS IN. AFTER A COLD START...SW FLOW AND PLENTY OF SUNSHINE SHOULD ALLOW TEMPS TO RECOVER TO NR NORMAL READINGS BY SAT AFTN. && .LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)... A SERIES OF WEAK CLIPPER SYSTEMS PASSING TO OUR NORTH NOT LIKELY TO BRING SIG PRECIP TO OUR AREA. HOWEVER...EACH SHOULD REINFORCE THE CHILL OVER OUR REGION. LOOKS RELATIVELY DRY BUT COLD FOR MOST OF NEXT WEEK. && .AVIATION... WIDESPREAD IFR CONDITIONS THIS MORNING IN MODERATE TO HEAVY SNOW...TAPERING TO LIGHTER SNOW BY MID MORNING...FROM WEST TO EAST. MUCH OF THE DAY WILL BE MVFR IN SC...BUT VFR CONDITIONS EXPECTED LATER THIS AFTERNOON...AS THE STORM PULLS AWAY...AND HIGH PRESSURE BUILDS NORTHWARD. && .CTP WATCHES/WARNINGS/ADVISORIES... HEAVY SNOW WARNING FOR PAZ006-010>012-017>019-024>028-033>037- 041-042-045-046-049>053-056>059-063>066 UNTIL 11 AM FRIDAY. SNOW ADVISORY FOR PAZ004-005 UNTIL 11 AM FRIDAY. && $$ SHORT TERM...FITZGERALD LONG TERM...FITZGERALD AVIATION...MARTIN pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 605 AM EST FRI DEC 9 2005 .UPDATE... POCKETS OF -SHSN/FLURRIES CONTINUE FROM ROUGHLY LOU/FTK AREA OVER IN LEX. STEEP LAPSE RATES UP TO 900MB (-14C LEVEL) SEEN IN 1040 UTC ACARS SOUNDING AT SDF...BUFKIT DATA SHOWS THIS ENVIRONMENT CONTINUING THROUGH THE MORNING SO WILL CONTINUE -SHSN/FLURRIES. COULD SEE SOME MINOR TRACE ACCUMULATIONS...SLICK SPOTS LIKELY FROM REFREEZE LAST NIGHT AS WELL (REFERENCE ONGOING SPS). REFINED CLOUD COVER GRIDS FOR NEXT 6-9 HOURS BASED ON ANTICIPATION THAT SECOND AREA OF LOW CLOUDS CURRENTLY OVER ERN IL/WRN IND WILL DROP INTO THE SRN IND/LOU/LEX ZONES THIS MORNING. WILL INCLUDE THIS TREND IN THE 12 UTC TAF ISSUANCE. WITH SNOW COVER...IT HAS DROPPED TO 7 AT HNB LAST HOUR...WITH WIDESPREAD MIDDLE/UPPER TEENS ELSEWHERE. WIND CHILLS NEAR OR JUST BELOW ZERO CONTINUE FOR PARTS OF THE AREA. CS .SHORT TERM (TODAY-TONIGHT)... ...VERY COLD OVER NEXT 24 HOURS... IN THE WAKE OF POTENT UPPER TROF BARRELING EASTWARD OVER IN/OH... WESTERLIES HAVE BEEN GUSTY OVER THE CWA...G25-30KTS COMMON DURING THE PAST FEW HOURS. WIND CHILLS INTO SINGLE DIGITS TO NEAR ZERO THROUGH THE PRE-DAWN HOURS. GRADIENT LOOKS TO RELAX CONSIDERABLY THIS MORNING PER BUFKIT SOUNDINGS AS SFC HIGH MOVES INTO THE REGION. THERE WERE SOME BLOWING SNOW ISSUES OVER INDIANA EARLIER...THOUGH WITH WINDS SETTLING DOWN THIS WILL BECOME LESS OF AN ISSUE FOR SRN INDIANA. LOW STRATUS REMAINS OVER MUCH OF THE CWA AS OF 06 UTC...SOME BREAKS ALONG/WEST OF I-65. EMBEDDED WITHIN...A RATHER PERSISTENT BAND OF -SHSN/FLURRIES HAS DEVELOPED FROM BRECKINRIDGE COUNTY OVER INTO THE FTK/LOU/FFT AREAS...PRODUCING SOME TRACE ACCUMULATIONS. BUFKIT SOUNDINGS INDICATE SHALLOW LAYER OF STEEP LAPSE RATES INTO THE -10 TO -15C LEVEL PERSISTING INTO THE MORNING HOURS...SO WILL CONTINUE TO MENTION SCT LIGHT SNOW SHOWERS OR FLURRIES. THERE HAVE BEEN REPORTS OF ACCIDENTS DUE TO REFREEZE FROM YESTERDAYS PCPN... SOMETHING THAT MORNING COMMUTERS WILL HAVE TO KEEP IN MIND... ESPECIALLY IN PARKING LOTS AND UNTREATED SURFACES. CLOUD FCST WILL BE CHALLENGING. RUC/NAM 925MB RH FIELDS DEPICT THE CURRENT CLOUD DISTRIBUTION WELL...AND INDICATE CLEARING FROM SW-NE THROUGHOUT THE DAY WHICH SEEMS REASONABLE...GIVEN RELATIVELY SHALLOW NATURE OF THE MOISTURE. THOUGH WITH BOUNDARY LAYER WINDS SWITCHING FROM W TO N/NW TODAY...THAT MAY SLOW THE PROGRESSION OF CLEARING SUCH THAT PARTS OF SE IND INTO LEX/BLUEGRASS COUNTIES MAY STAY CLOUDY LONGER. TEMPERATURES ARE ANOTHER CONCERN. WITH 850MB TEMPS NEAR -10C PER RUC ANALYSIS AND SDF ACARS SOUNDINGS...A VERY COLD DAY IS IN STORE ESPECIALLY AREAS THAT WOULD HAVE MORE CLOUD COVER. LEANED TOWARD RAW NAM/MOS NUMBERS. SNOWCOVER OVER SRN IND WILL HAVE A DOWNWARD INFLUENCE ON TEMPS TONIGHT...THOUGH THERE COULD BE SOME HIGH CLOUDS AFTER MIDNIGHT AHEAD OF ANOTHER UPPER SHORTWAVE APPROACHING. WON'T GO AS COLD AS RAW NAM DATA TONIGHT...BUT SOME UPPER SINGLE DIGIT READINGS POSSIBLE IN SRN IND...WITH LOW/MIDDLE TEENS ELSEWHERE IN THE CWA. CS .LONG TERM (SATURDAY-THURSDAY)... .SATURDAY... EXPECT A TRANQUIL DAY AS LOWER OHIO VALLEY WILL REMAIN BETWEEN SYSTEMS. HIGH PRESSURE ACROSS THE SOUTHEASTERN STATES WILL PROVIDE SUNNY SKIES WITH LIGHT WINDS...ALBEIT WITH STILL CHILLY TEMPERATURES. LIGHT WINDS IN THE MORNING WILL BECOME SOUTHWEST IN THE AFTERNOON AS WINDS INCREASE A BIT AHEAD OF A SURFACE TROUGH MOVING SOUTH ACROSS THE UPPER MIDWEST. .SUNDAY... AS A REX BLOCK SHARPENS ACROSS THE WEST COAST...TROUGH WILL AMPLIFY ALONG THE MISSISSIPPI VALLEY AS JET STREAM ENERGY DROPS SOUTHWARD ACROSS CENTRAL US. SURFACE TROUGH ASSOCIATED WITH LOW PRESSURE MOVING ACROSS THE GREAT LAKES WILL PUSH A REINFORCING COLD SURGE DURING THE DAY ON SUNDAY. LOW LEVEL MOISTURE WILL INCREASE SUNDAY AND CANNOT RULE OUT CHANCE OF LIGHT SNOW DURING THE DAY AND SUNDAY NIGHT. CHANCES OF SNOW MAY CONTINUE THROUGH EARLY MONDAY AS ISENTROPIC LIFT INCREASES ACROSS AN ELEVATED FRONT EXPECTED TO DEVELOP ACROSS KENTUCKY. .TUESDAY THROUGH THURSDAY... THIS PERIOD MAY BE THE START OF AN UPPER AIR TRANSITIONAL PERIOD AS REX BLOCK ACROSS WEST COAST BREAKS DOWN DUE TO WESTERLIES UNDERCUTTING THE RIDGE. TEMPERATURES ACROSS THE LOWER OHIO VALLEY...RUNNING AROUND 13 DEGREES BELOW NORMAL FOR THE MONTH OF DEC SO FAR...MAY MODERATE AS PERSISTENT COLD TROUGH EASES AND MOVES EAST TOWARDS NEW ENGLAND. WITH A SPLIT FLOW PATTERN MOVING EAST ACROSS THE PLAINS...THE LOWER OHIO VALLEY LOOKS STORM FREE THIS PERIOD. WILL KEEP JUST A CHANCE OF PRECIP IN FORECAST WEDNESDAY AS A WEAK DISTURBANCE MOVES ACROSS UPPER OHIO VALLEY. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1100 AM EST FRI DEC 9 2005 ...MESOSCALE CONVECTIVE BAND OF SNOW DEVELOPING IN LOWER CT VALLEY TO SOUTHERN NH... .MESO/NEAR TERM UPDATE... 15Z MESOANALYSIS INDICATES A COASTAL FRONT EXTENDING FROM ISLIP NY NORTHEAST ALONG LONG ISLAND...NEAR COASTAL RI...NORTHEAST TO NEW BEDFORD...NORTH TO BEVERLY. ALSO...A SURFACE TROF IS FORMING FROM THE LOW CENTER SOUTH OF ISLIP...NORTHWARD PAST NORTH ADAMS MA. 40 KM NAM SHOWS STRONG FRONTOGENESIS ALONG THESE 2 FEATURES FROM 15Z TO 18Z...AS THE LOW MOVES EAST. KALY RADAR SHOWING A DEVELOPING BAND OF HEAVY SNOW WITH 30 TO EVEN 40 DBZ REFLECTIVITY...MESOSCALE CONVECTIVE BAND....UNDER SURFACE TROF AND WHERE SECONDARY BAND OF STRONG FRONTOGENESIS WAS INDICATED. THUNDERSNOW REPORTED IN CHICOPEE AT 1050 AM...1/4SM S+ AT HFD...BAF...CEF AND AQW. KEENE NH REPORTS 10 INCHES OF SNOWFALL SO FAR. AT THIS TIME...THIS HEAVY SNOW BAND IS EXPECTED TO MOVE GRADUALLY EASTWARD ACROSS MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE THROUGH EARLY THIS AFTERNOON. SNOWFALL RATES OF 1 TO 2 INCHES AN HOUR...AND ISOLATED 3 INCH PER HOUR SNOWFALL...ARE EXPECTED UNDER 30 TO 40 DBZ REFLECTIVITY. FOR COASTAL SOUTHERN NEW ENGLAND...KBOX RADAR PICKING UP ON BRIGHT BANDING...SOME MELTING OCCURRING ALOFT WITH REPORTS OF SLEET...RAIN ...AND FREEZING RAIN IN SOUTH COASTAL MA AND COASTAL RI. MIX TO RAIN LINE WAS ALONG A KINGSTON...PVD...PYM TO NEAR BVY LINE. COASTAL FRONT MAY PULL INLAND SOME OVER NEXT FEW HOURS. MIX SUPPORTS KEEPING WINTER WEATHER ADVISORIES AS THEY ARE AT THIS TIME. && .MARINE... MSAS INDICATING RAPID SURFACE PRESSURE FALLS OF UP TO 9 MB IN 3 HOURS...AND TIGHTENING GRADIENT. PLAN TO MENTION GUSTS TO 55 KT IN OUTER COASTAL WATERS...WHERE STORM WARNINGS ARE ALREADY IN EFFECT. NBELK && PREVIOUS DISCUSSION... (ISSUED 920 AM EST FRI DEC 9 2005)... .MESO/SHORT TERM UPDATE (REST OF TODAY)... COMPLEX WINTER SCENARIO UNFOLDING THIS AM...ESPECIALLY CAPE COD CANAL TO I95 CORRIDOR WHERE CSTL FNT BEGINNING TO DVLP. PARENT SFC LOW OVR LK ONTARIO BEGINNING TO WEAKEN/FILL...WHILE CSTL LOW JUST E OF NJ BEGINS TO INTENSIFY WITH SIGNIFICANT PRES FALLS CENTERED JUST S. OF MONTAUK ON THE ORDER OF -8 MBS DURING THE PAST 3 HRS. THESE PRES FALLS WL GRADUALLY BACK SFC WNDS TO N-NE OVR THE AREA AS THE MORNING PROGRESSES...WHICH WL RETARD THE N MVMNT OF THE CSTL FNT AND MIXED PRECIP LINE. THIS IS APPARENT IN THE 14Z SFC OBS...WITH SE WND AT BID AND NE WND AT GON AND WST. THE RESULT HERE IS FOR SUBFREEZING SFC LYR TO BE DELAYED MVG NWD FM CAPE COD CANAL TO I95. FURTHER COMPLICATING THIS AREA...IS THAT SUFFICIENT WARMING/MELTING IS OCCURRING ABV THE SFC LYR (PER STG SE INFLOW ON KBOX VAD WND PROFILE) ACRS THIS AREA FOR SN TO CHANGE TO SLEET AND OR FREEZING RN...AS WST AND GON RPTG -FZRA ANS SVRL SPOTTER RPTG SLEET. ALSO...KBOX COMPOSITE RADAR IMAGERY PICKING UP ON THIS WELL...WITH HIGH REFLECTIVITY OVR NARRAGANSETT BAY INDICATING SLEET. SO CURRENT FCST OF RN-SN LINE TRAVERSING NWWD INTO I95 CORRIDOR AND PSSBLY AS FAR NW AS I495 LKS GD. HWR...GIVEN LATEST TRENDS/CSTL FNT DVLPMNT AND STG PRES FALLS...SUBFREEZING SFC LYR WL BE DELAYED MVG NWD AND WL YIELD MORE OF A WINTRY MIX OF FZRA AND SLEET FM CAPE COD CANAL INTO I95. THUS...WL UPDATED WX GRIDS TO REFLECT MIXED PTYPE TRANSITION...RATHER THAN A CLEAN PTYPE CHANGE FM SN TO RN. INLAND...ESPECIALLY N OF THE MASS TURNPIKE AND NW OF I495 IT IS FAIRLY STRAIGHT FORWARD...WITH PTYPE REMAINING ALL SNOW. NO CHANGES TO SNOW ACCUMULATIONS AT THE MOMENT. ALTH...WL HV TO WATCH TRENDS OF CSTL FNT ALONG WITH STG PRES FALLS OFF THE S.CST. IF CSTL FNT REMAINS FARTHER S...BLYR WRMG MAY BE TOO MARGINAL FOR A CHANGEOVER AND STG UPWARD VERTICAL MOTION MAY BE ABLE TO COMPENSATE VIA DYNAMICAL AND DIABATIC COOLING PROCESSES. THEREFORE...COULD HAVE LESS MIXING IN FROM I495 TO I95 YIELDING HIER SN TOTALS. WL JUST HV TO MONITOR TRENDS AND AWAIT 12Z MDL GUID. NOCERA && .PREVIOUS DISCUSSION... (ISSUED 500 AM EST FRI DEC 9 2005) SHORT TERM (TODAY)... MESO DISCUSSION AND 06Z MODEL UPDATE... SNOW HAS MADE IT INTO NYC AND JUST STARTED IN HARTFORD AS WELL AS BERKSHIRES AND MONADNOCKS. KBOX RADAR SHOWS AN INITIAL BAND OF SNOW FROM MANCHESTER TO CAPE ANN AND OFFSHORE WHICH FOR MOST PART IS ALOFT...BUT IT IS GIVING A QUICK SHOT OF SNOW TO SOUTHERN NH. YOU CAN SEE THE DRY AIR AT LOWER LEVELS VERY WELL ON KBOX RADAR TOO... COVERING MUCH OF EASTERN MA AND RI. THIS WILL SLOWLY MOISTEN DURING NEXT COUPLE OF HOURS AND WE EXPECT SNOW TO REACH WORCESTER AND PROVIDENCE BY 7 AM AND BOSTON AROUND 8 AM OR SO. MODELS ARE TRENDING CLOSER WITH EACH RUN. 06Z NAM IS NOW A BIT FARTHER S WITH ITS LOW TRACK...NOW FROM MONTAUK POINT TO CAPE COD BAY WITH GFS HOLDING FIRM ON ITS TRACK S OF NANTUCKET. OTHER MESOSCALE MODELS INCLUDING 06Z RUC AND 06Z 10KM BOX ETA PREFER A TRACK CLOSER TO NAM...BUT THIS JUST SEEMS A BIT TOO FAR N TO US. ONE THING WE NOTICED IS NAM IS STILL A BIT SLOWER...AND BRINGS BEST LIFT INTO SOUTHERN NEW ENGLAND FROM MID MORNING INTO MID AFTERNOON...SO WE ARE STILL ON TARGET FOR 1-2"/HR SNOWFALL RATES...ESPECIALLY FOR HARTFORD TO WORCESTER AND LAWRENCE CORRIDOR WHERE SNOWFLAKE PRODUCTION WILL BE MAXIMIZED. WE HAVE SOME CONCERN THAT THIS STRONG LIFT MAY BE ABLE TO COMPENSATE ENOUGH FOR MARGINALLY WARM LOW LEVEL TEMPERATURES IN BOSTON AREA. IT STILL APPEARS WARM ENOUGH FOR A CHANGE TO RAIN IN PROVIDENCE AND SE MA. BOSTON MAY VERY WELL END UP SEEING MORE OF A MIX AS OPPOSED TO A CHANGE TO RAIN SHOULD NAM VERIFY...BUT A PROLONGED SE WIND USUALLY KILLS THE SNOWFLAKES IN BOSTON. ONE THING THAT HAS BEEN IMPRESSIVE SO FAR IS WHAT'S BEEN GOING ON UPSTREAM ACROSS MID ATLANTIC...ESPECIALLY FROM WASHINGTON DC INTO PA WHERE THERE HAVE BEEN MANY REPORTS OF 1-2"/HR SNOWFALL RATES AND EVEN THUNDER! THIS SHOULD ALL COME OUR WAY LATER THIS MORNING AND EARLY THIS AFTERNOON. JWD PREVIOUS DISCUSSION... (ISSUED 335 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH TONIGHT)... WE ARE KEEPING ALL WARNINGS AND ADVISORIES IN PLACE FOR SNOW TODAY... BUT WILL TRIM AMOUNTS DOWN SLIGHTLY NEAR I-95 CORRIDOR WHICH SHOULD SERVE AS OUR TRANSITION ZONE. TOTALS ACROSS INTERIOR LOOK GOOD. WE WILL ALSO UPGRADE THE HIGH WIND WATCH FOR CAPE COD AND THE ISLANDS TO A HIGH WIND WARNING. LEADING EDGE OF SNOW IS CURRENTLY WORKING THROUGH CENTRAL NY AND EASTERN PA...NOTE HOW QUICKLY VISIBILITIES DROP TO 1/2SM OR LESS AS SNOW BEGINS! ALTHOUGH WE HAVE PLENTY OF LOW LEVEL DRY AIR TO OVERCOME...IT WON'T TAKE LONG TO SATURATE THE COLUMN WITH SUCH A POTENT SYSTEM ON OUR DOORSTEP. WE EXPECT SNOW TO BEGIN IN CT VALLEY AROUND SUNRISE (PROBABLY 6 AM) AND QUICKLY HEAD TO E MA COAST DURING MORNING RUSH HOUR (8-9 AM)...PLUS/MINUS AN HOUR OR TWO. 00Z NAM STILL FARTHEST N OF MODELS THIS MORNING...BUT 00Z GFS CONTINUES ITS TREND OF EDGING FARTHER N WITH EACH RUN...NOW TAKING SECONDARY LOW JUST SE OF NANTUCKET. IT AGREES WELL WITH ITS 00Z ENSEMBLE MEMBERS AND MATCHES WELL WITH ENSEMBLE MEAN. WE ALSO LOOKED AT 00Z NGM...AND IT ACTUALLY PRESENTS A DECENT SOLUTION. ITS SURFACE LOW IS SIMILAR TO GFS...BUT WE LIKE ITS 24HR QPF OF 0.50 TO 1.00" WHICH IS MUCH LOWER THAN NAM/GFS. OFTEN WE LIKE TO SEE NGM ON BOARD WITH SIGNIFICANT QPF BEFORE JUMPING ON A BIG EVENT...AND SINCE WE HAVE HAD DOUBTS AS TO EXCESSIVE QPF AMOUNTS SHOWN ON PAST RUNS OF NAM/GFS THIS LEADS MORE CREDENCE TO FACT THAT THOSE TWO MODELS ARE PROBABLY OVERDOING IT...ESPECIALLY GIVEN PROGRESSIVE NATURE OF THIS SYSTEM AS UPPER LOW DOES NOT CUTOFF UNTIL IT PASSES CAPE COD. SO IF WE ADJUST OUR TRACK TO JUST INSIDE 40/70 BENCHMARK...IT WOULD PLACE HEAVIEST PRECIPITATION ACROSS INTERIOR FROM NORTHERN CT INTO CENTRAL/INTERIOR NE MA AND SW NH. CROSS SECTIONS STILL SHOW TREMENDOUS MID LEVEL FRONTOGENESIS IN THIS REGION WITH EXCELLENT POTENTIAL FOR SLANTWISE CONVECTION/MESOSCALE BANDING. THIS IS ALSO ZONE OF MAXIMUM SNOW GROWTH. ONLY LIMITING FACTOR TO MAKING THIS A BLOCKBUSTER EVENT CONTINUES TO BE SPEED OF SYSTEM...SO ALTHOUGH IT'S GOING TO SNOW HARD FOR SEVERAL HOURS FROM MID MORNING INTO EARLY AFTERNOON WITH SNOWFALL RATES OF 2" PER HOUR...IT SHOULD NOT LAST LONG ENOUGH TO GIVE WIDESPREAD TOTALS OVER 10". WE'LL PROBABLY GET SOME THUNDER/LIGHTNING REPORTS WITH THIS AS WELL. CLOSER TO COAST...WE NEED TO DEAL WITH PRECIPITATION TYPE AS WE HAVE NO BLOCKING HIGH TO NORTH TO KEEP COLD AIR LOCKED IN AT LOW LEVELS. WINDS SHOULD EASILY BE ABLE TO TURN SE LATER THIS MORNING...ESPECIALLY SINCE MODELS SHOW 1000 MB AGEOSTROPHIC WINDS TURNING W...NOT A GOOD SIGN TO KEEP IT COLD. GFS CROSS SECTIONS MAY BE A LITTLE TOO WARM...INDICATING A CHANGE TO RAIN AS FAR INLAND AS I-495 IN EASTERN MA AND INTO NW RI. WE THINK IT IS MORE REALISTIC THAT THE TRANSITION ZONE (IE RAIN/SNOW MIX) WILL END UP NEAR I-95 BETWEEN BOSTON AND PROVIDENCE AND PROBABLY AS FAR N AS CAPE ANN. A COMPLETE CHANGE TO RAIN SEEMS MOST LIKELY WITHIN 5-10 MILES OF THE COAST FROM BOSTON TO PLYMOUTH...THEN ACROSS SE MA NEAR TAUNTON AND INTO PROVIDENCE. THAT BEING SAID...WE WILL NUDGE STORM TOTALS DOWN SLIGHTLY IN THESE LOCATIONS. WE CURRENTLY HAVE SE MIDDLESEX AND W NORFOLK COUNTIES IN A LOW-END WINTER STORM WARNING AND THAT STILL SEEMS REASONABLE...AS WE THINK PLACES ALONG ROUTE 128 FROM WOBURN AND BELMONT TO NEWTON AND DEDHAM WILL SEE THE 4-5" AMOUNTS AND LOCATIONS FARTHER INLAND SUCH AS LEXINGTON AND ESPECIALLY MEDWAY AND BELLINGHAM WILL SEE THE 6-8" TOTALS. IN THOSE ZONES WHERE WE HAVE A WINTER WEATHER ADVISORY...WE WILL GENERALLY HAVE 2-4" TOTALS. ONE EXCEPTION TO THIS IS IN COASTAL ESSEX COUNTY MA (ZONE 7)...WHERE WE EXPECT A WIDE RANGE IN TOTALS... FROM 2" ON COASTLINE TO AS MUCH AS 7-8" NEAR NH BORDER. BUT AVERAGE IS LOW ENOUGH TO KEEP AN ADVISORY GOING THERE. HEAVIEST SNOW SHOULD SHIFT INTO MERRIMACK VALLEY EARLY THIS AFTERNOON WHILE SNOWFALL RATES DECREASE BACK ACROSS CT VALLEY. STRONGEST LIFT IS HEADING QUICKLY FOR COAST BY MID AFTERNOON...SO WE THINK MANY LOCATIONS WILL SEE IMPROVING CONDITIONS BY 3 OR 4 PM EXCEPT FOR CAPE COD AND ISLANDS. MAIN CONCERN THEN BECOMES WIND. SURFACE LOW DEEPENING RAPIDLY OFF CAPE COD WILL CAUSE A RAPID INCREASE IN WINDS THROUGHOUT ALL OF REGION...BUT ESPECIALLY NEAR COAST. IF WE TAKE GFS SOUNDINGS FOR HYANNIS AND NANTUCKET AT FACE VALUE IT SHOWS A STRONG POTENTIAL OF 50-60KT GUSTS AS THIS DEEPENING OCCURS LATE THIS AFTERNOON AND EVENING. WE THINK THIS MAY BE A LITTLE HIGH...BUT WE HAVE ENOUGH CONFIDENCE TO ISSUE HIGH WIND WARNINGS AT THIS TIME. WIND ADVISORY WILL BE KEPT IN PLACE FOR S COAST...EVEN THOUGH CONFIDENCE ON 40KT GUSTS THERE IS LESS. ADVISORIES MAY ALSO NEED TO BE ISSUED FOR E MA COASTLINE BUT RIGHT NOW WE THINK WE WILL FALL SHORT OF CRITERIA THERE. CLEARING SHOULD WORK IN RAPIDLY THIS EVENING AS CROSS SECTIONS SHOW RAPID DRYING AND STRONG SUBSIDENCE...BUT WINDS WILL ONLY DIMINISH GRADUALLY UNTIL SYSTEM PULLS FARTHER OFFSHORE. LONG TERM (SATURDAY THROUGH THURSDAY)... OVERALL COLD AIR REMAINS IN PLACE OVER REGION THROUGH AT LEAST THURSDAY. WEAK RIDGE BUILDS OVER REGION SATURDAY IN WAKE OF DEPARTING STORM. SATURDAY NIGHT HEIGHTS BEGIN TO FALL AND WINDS BACK AS CYCLONIC FLOW BEGINS TO TAKE OVER. SHORTWAVES MOVE OVERHEAD THROUGH MONDAY WHILE AT THE SURFACE A DISORGANIZED LOW PRESSURE AREA MOVES ACROSS SOUTHERN QUEBEC TOWARD THE CANADIAN MARITIMES. COLD AIR ADVECTION ACROSS REGION COULD YIELD SHOWERS OVER OUTER WATERS CLIPPING CAPE AND ISLANDS. SURFACE HIGH PRESSURE BUILDS SOUTHEAST FROM CENTRAL CANADA...AND RESULTING N TO NW WINDS OVER CAPE COULD YIELD OCEAN EFFECT SNOW SHOWERS TUESDAY AND WEDNESDAY. RIDGING THROUGH THE COLUMN BUILDS OVER NEW ENGLAND THURSDAY...THEN REGION AWAITS NEXT POTENTIAL NOREASTER FOR FRIDAY. AVIATION... VFR FOR THE MOMENT...EXCEPT FOR MVFR CEILINGS NEAR NANTUCKET WHICH WILL SPREAD ONTO S COAST EARLY THIS MORNING. CONDITIONS WILL DETERIORATE RAPIDLY THIS MORNING TO IFR AS SNOW ARRIVES (THEN TO LIFR WITHIN 2 HOURS OF THAT)...CURRENTLY TIMED INTO CT VALLEY TOWARD SUNRISE AND BEFORE MID MORNING ALONG E MA COAST. CONDITIONS WILL LIFT TO MVFR THIS AFTERNOON AS HEAVIER SNOW SHIFTS OFFSHORE...THEN WE EXPECT RAPID IMPROVEMENT TO VFR BY EARLY THIS EVENING AS LOW PULLS OFF THE COAST. MARINE... WE WILL EXPAND STORM WARNINGS THIS AFTERNOON TO INCLUDE CAPE COD BAY AND NANTUCKET SOUND...AND MAINTAIN GALE WARNINGS ELSEWHERE AS WINDS INCREASE RAPIDLY BEHIND DEPARTING LOW. THERE IS STILL SOME QUESTION AS TO HOW FAST THE LOW WILL DEEPEN...IMPACTING WIND GUST POTENTIAL... BUT IT IS MORE LIKELY IT WILL OCCUR CLOSE ENOUGH TO CAPE COD RATHER THAN FARTHER OFFSHORE. WINDS AND SEAS SLOWLY DIMINISH OVERNIGHT AS SYSTEM PULLS FARTHER AWAY. FOLLOWED WNA WAVE GUIDANCE...HOWEVER GIVEN PREVAILING WEST TO SOUTHWEST WINDS SATURDAY AND SUNDAY...INCREASED SEAS IN BUZZARDS BAY. SMALL CRAFT ADVISORY CONDITIONS EXPECTED OVER THE WEEKEND FOR OUTER WATERS AND ALONG SOUTH COAST...ALL DUE TO WIND GUSTS TO 30 KTS AND ROUGH SEAS. WINDS AND SEAS SUBSIDE MONDAY AND TUESDAY. CLIMATE... FYI...RECORD DAILY SNOWFALL TOTALS FOR TODAY ARE AS FOLLOWS... KBOS... 4.6 INCHES IN 1978 KPVD... 3.0 INCHES IN 1995 KORH... 8.0 INCHES IN 1903 KBDL... 4.2 INCHES IN 1995 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAVY SNOW WARNING FOR CTZ002>004 UNTIL 4 PM FRIDAY. MA...HEAVY SNOW WARNING FOR MAZ002>004-008>012 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR MAZ005-006-013-014-026 UNTIL 5 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR MAZ007-015>019 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR MAZ020-021 FROM 4 PM FRIDAY TO 1 AM SATURDAY. ...HIGH WIND WARNING FOR MAZ022>024 FROM 4 PM FRIDAY TO 1 AM SATURDAY. NH...HEAVY SNOW WARNING FOR NHZ011 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR NHZ012-015 UNTIL 5 PM FRIDAY. RI...HEAVY SNOW WARNING FOR RIZ001 UNTIL 4 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR RIZ002>005 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR RIZ006>008 FROM 4 PM FRIDAY TO 1 AM SATURDAY. MARINE...GALE WARNING FOR ANZ230-233>237 FROM 1 PM FRIDAY TO 1 AM SATURDAY. ...STORM WARNING FOR ANZ231-232-250-254-255 FROM 1 PM FRIDAY TO 1 AM SATURDAY. && $$ SHORT TERM...NOCERA ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 920 AM EST FRI DEC 9 2005 ...COMPACT-POTENT WINTER STORM IN PROGRESS... .MESO/SHORT TERM UPDATE (REST OF TODAY)... COMPLEX WINTER SCENARIO UNFOLDING THIS AM...ESPECIALLY CAPE COD CANAL TO I95 CORRIDOR WHERE CSTL FNT BEGINNING TO DVLP. PARENT SFC LOW OVR LK ONTARIO BEGINNING TO WEAKEN/FILL...WHILE CSTL LOW JUST E OF NJ BEGINS TO INTENSIFY WITH SIGNIFICANT PRES FALLS CENTERED JUST S. OF MONTAUK ON THE ORDER OF -8 MBS DURING THE PAST 3 HRS. THESE PRES FALLS WL GRADUALLY BACK SFC WNDS TO N-NE OVR THE AREA AS THE MORNING PROGRESSES...WHICH WL RETARD THE N MVMNT OF THE CSTL FNT AND MIXED PRECIP LINE. THIS IS APPARENT IN THE 14Z SFC OBS...WITH SE WND AT BID AND NE WND AT GON AND WST. THE RESULT HERE IS FOR SUBFREEZING SFC LYR TO BE DELAYED MVG NWD FM CAPE COD CANAL TO I95. FURTHER COMPLICATING THIS AREA...IS THAT SUFFICIENT WARMING/MELTING IS OCCURRING ABV THE SFC LYR (PER STG SE INFLOW ON KBOX VAD WND PROFILE) ACRS THIS AREA FOR SN TO CHANGE TO SLEET AND OR FREEZING RN...AS WST AND GON RPTG -FZRA ANS SVRL SPOTTER RPTG SLEET. ALSO...KBOX COMPOSITE RADAR IMAGERY PICKING UP ON THIS WELL...WITH HIGH REFLECTIVITY OVR NARRAGANSETT BAY INDICATING SLEET. SO CURRENT FCST OF RN-SN LINE TRAVERSING NWWD INTO I95 CORRIDOR AND PSSBLY AS FAR NW AS I495 LKS GD. HWR...GIVEN LATEST TRENDS/CSTL FNT DVLPMNT AND STG PRES FALLS...SUBFREEZING SFC LYR WL BE DELAYED MVG NWD AND WL YIELD MORE OF A WINTRY MIX OF FZRA AND SLEET FM CAPE COD CANAL INTO I95. THUS...WL UPDATED WX GRIDS TO REFLECT MIXED PTYPE TRANSITION...RATHER THAN A CLEAN PTYPE CHANGE FM SN TO RN. INLAND...ESPECIALLY N OF THE MASS TURNPIKE AND NW OF I495 IT IS FAIRLY STRAIGHT FORWARD...WITH PTYPE REMAINING ALL SNOW. NO CHANGES TO SNOW ACCUMULATIONS AT THE MOMENT. ALTH...WL HV TO WATCH TRENDS OF CSTL FNT ALONG WITH STG PRES FALLS OFF THE S.CST. IF CSTL FNT REMAINS FARTHER S...BLYR WRMG MAY BE TOO MARGINAL FOR A CHANGEOVER AND STG UPWARD VERTICAL MOTION MAY BE ABLE TO COMPENSATE VIA DYNAMICAL AND DIABATIC COOLING PROCESSES. THEREFORE...COULD HAVE LESS MIXING IN FROM I495 TO I95 YIELDING HIER SN TOTALS. WL JUST HV TO MONITOR TRENDS AND AWAIT 12Z MDL GUID. NOCERA && .PREVIOUS DISCUSSION... (ISSUED 500 AM EST FRI DEC 9 2005) SHORT TERM (TODAY)... MESO DISCUSSION AND 06Z MODEL UPDATE... SNOW HAS MADE IT INTO NYC AND JUST STARTED IN HARTFORD AS WELL AS BERKSHIRES AND MONADNOCKS. KBOX RADAR SHOWS AN INITIAL BAND OF SNOW FROM MANCHESTER TO CAPE ANN AND OFFSHORE WHICH FOR MOST PART IS ALOFT...BUT IT IS GIVING A QUICK SHOT OF SNOW TO SOUTHERN NH. YOU CAN SEE THE DRY AIR AT LOWER LEVELS VERY WELL ON KBOX RADAR TOO... COVERING MUCH OF EASTERN MA AND RI. THIS WILL SLOWLY MOISTEN DURING NEXT COUPLE OF HOURS AND WE EXPECT SNOW TO REACH WORCESTER AND PROVIDENCE BY 7 AM AND BOSTON AROUND 8 AM OR SO. MODELS ARE TRENDING CLOSER WITH EACH RUN. 06Z NAM IS NOW A BIT FARTHER S WITH ITS LOW TRACK...NOW FROM MONTAUK POINT TO CAPE COD BAY WITH GFS HOLDING FIRM ON ITS TRACK S OF NANTUCKET. OTHER MESOSCALE MODELS INCLUDING 06Z RUC AND 06Z 10KM BOX ETA PREFER A TRACK CLOSER TO NAM...BUT THIS JUST SEEMS A BIT TOO FAR N TO US. ONE THING WE NOTICED IS NAM IS STILL A BIT SLOWER...AND BRINGS BEST LIFT INTO SOUTHERN NEW ENGLAND FROM MID MORNING INTO MID AFTERNOON...SO WE ARE STILL ON TARGET FOR 1-2"/HR SNOWFALL RATES...ESPECIALLY FOR HARTFORD TO WORCESTER AND LAWRENCE CORRIDOR WHERE SNOWFLAKE PRODUCTION WILL BE MAXIMIZED. WE HAVE SOME CONCERN THAT THIS STRONG LIFT MAY BE ABLE TO COMPENSATE ENOUGH FOR MARGINALLY WARM LOW LEVEL TEMPERATURES IN BOSTON AREA. IT STILL APPEARS WARM ENOUGH FOR A CHANGE TO RAIN IN PROVIDENCE AND SE MA. BOSTON MAY VERY WELL END UP SEEING MORE OF A MIX AS OPPOSED TO A CHANGE TO RAIN SHOULD NAM VERIFY...BUT A PROLONGED SE WIND USUALLY KILLS THE SNOWFLAKES IN BOSTON. ONE THING THAT HAS BEEN IMPRESSIVE SO FAR IS WHAT'S BEEN GOING ON UPSTREAM ACROSS MID ATLANTIC...ESPECIALLY FROM WASHINGTON DC INTO PA WHERE THERE HAVE BEEN MANY REPORTS OF 1-2"/HR SNOWFALL RATES AND EVEN THUNDER! THIS SHOULD ALL COME OUR WAY LATER THIS MORNING AND EARLY THIS AFTERNOON. JWD PREVIOUS DISCUSSION... (ISSUED 335 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH TONIGHT)... WE ARE KEEPING ALL WARNINGS AND ADVISORIES IN PLACE FOR SNOW TODAY... BUT WILL TRIM AMOUNTS DOWN SLIGHTLY NEAR I-95 CORRIDOR WHICH SHOULD SERVE AS OUR TRANSITION ZONE. TOTALS ACROSS INTERIOR LOOK GOOD. WE WILL ALSO UPGRADE THE HIGH WIND WATCH FOR CAPE COD AND THE ISLANDS TO A HIGH WIND WARNING. LEADING EDGE OF SNOW IS CURRENTLY WORKING THROUGH CENTRAL NY AND EASTERN PA...NOTE HOW QUICKLY VISIBILITIES DROP TO 1/2SM OR LESS AS SNOW BEGINS! ALTHOUGH WE HAVE PLENTY OF LOW LEVEL DRY AIR TO OVERCOME...IT WON'T TAKE LONG TO SATURATE THE COLUMN WITH SUCH A POTENT SYSTEM ON OUR DOORSTEP. WE EXPECT SNOW TO BEGIN IN CT VALLEY AROUND SUNRISE (PROBABLY 6 AM) AND QUICKLY HEAD TO E MA COAST DURING MORNING RUSH HOUR (8-9 AM)...PLUS/MINUS AN HOUR OR TWO. 00Z NAM STILL FARTHEST N OF MODELS THIS MORNING...BUT 00Z GFS CONTINUES ITS TREND OF EDGING FARTHER N WITH EACH RUN...NOW TAKING SECONDARY LOW JUST SE OF NANTUCKET. IT AGREES WELL WITH ITS 00Z ENSEMBLE MEMBERS AND MATCHES WELL WITH ENSEMBLE MEAN. WE ALSO LOOKED AT 00Z NGM...AND IT ACTUALLY PRESENTS A DECENT SOLUTION. ITS SURFACE LOW IS SIMILAR TO GFS...BUT WE LIKE ITS 24HR QPF OF 0.50 TO 1.00" WHICH IS MUCH LOWER THAN NAM/GFS. OFTEN WE LIKE TO SEE NGM ON BOARD WITH SIGNIFICANT QPF BEFORE JUMPING ON A BIG EVENT...AND SINCE WE HAVE HAD DOUBTS AS TO EXCESSIVE QPF AMOUNTS SHOWN ON PAST RUNS OF NAM/GFS THIS LEADS MORE CREDENCE TO FACT THAT THOSE TWO MODELS ARE PROBABLY OVERDOING IT...ESPECIALLY GIVEN PROGRESSIVE NATURE OF THIS SYSTEM AS UPPER LOW DOES NOT CUTOFF UNTIL IT PASSES CAPE COD. SO IF WE ADJUST OUR TRACK TO JUST INSIDE 40/70 BENCHMARK...IT WOULD PLACE HEAVIEST PRECIPITATION ACROSS INTERIOR FROM NORTHERN CT INTO CENTRAL/INTERIOR NE MA AND SW NH. CROSS SECTIONS STILL SHOW TREMENDOUS MID LEVEL FRONTOGENESIS IN THIS REGION WITH EXCELLENT POTENTIAL FOR SLANTWISE CONVECTION/MESOSCALE BANDING. THIS IS ALSO ZONE OF MAXIMUM SNOW GROWTH. ONLY LIMITING FACTOR TO MAKING THIS A BLOCKBUSTER EVENT CONTINUES TO BE SPEED OF SYSTEM...SO ALTHOUGH IT'S GOING TO SNOW HARD FOR SEVERAL HOURS FROM MID MORNING INTO EARLY AFTERNOON WITH SNOWFALL RATES OF 2" PER HOUR...IT SHOULD NOT LAST LONG ENOUGH TO GIVE WIDESPREAD TOTALS OVER 10". WE'LL PROBABLY GET SOME THUNDER/LIGHTNING REPORTS WITH THIS AS WELL. CLOSER TO COAST...WE NEED TO DEAL WITH PRECIPITATION TYPE AS WE HAVE NO BLOCKING HIGH TO NORTH TO KEEP COLD AIR LOCKED IN AT LOW LEVELS. WINDS SHOULD EASILY BE ABLE TO TURN SE LATER THIS MORNING...ESPECIALLY SINCE MODELS SHOW 1000 MB AGEOSTROPHIC WINDS TURNING W...NOT A GOOD SIGN TO KEEP IT COLD. GFS CROSS SECTIONS MAY BE A LITTLE TOO WARM...INDICATING A CHANGE TO RAIN AS FAR INLAND AS I-495 IN EASTERN MA AND INTO NW RI. WE THINK IT IS MORE REALISTIC THAT THE TRANSITION ZONE (IE RAIN/SNOW MIX) WILL END UP NEAR I-95 BETWEEN BOSTON AND PROVIDENCE AND PROBABLY AS FAR N AS CAPE ANN. A COMPLETE CHANGE TO RAIN SEEMS MOST LIKELY WITHIN 5-10 MILES OF THE COAST FROM BOSTON TO PLYMOUTH...THEN ACROSS SE MA NEAR TAUNTON AND INTO PROVIDENCE. THAT BEING SAID...WE WILL NUDGE STORM TOTALS DOWN SLIGHTLY IN THESE LOCATIONS. WE CURRENTLY HAVE SE MIDDLESEX AND W NORFOLK COUNTIES IN A LOW-END WINTER STORM WARNING AND THAT STILL SEEMS REASONABLE...AS WE THINK PLACES ALONG ROUTE 128 FROM WOBURN AND BELMONT TO NEWTON AND DEDHAM WILL SEE THE 4-5" AMOUNTS AND LOCATIONS FARTHER INLAND SUCH AS LEXINGTON AND ESPECIALLY MEDWAY AND BELLINGHAM WILL SEE THE 6-8" TOTALS. IN THOSE ZONES WHERE WE HAVE A WINTER WEATHER ADVISORY...WE WILL GENERALLY HAVE 2-4" TOTALS. ONE EXCEPTION TO THIS IS IN COASTAL ESSEX COUNTY MA (ZONE 7)...WHERE WE EXPECT A WIDE RANGE IN TOTALS... FROM 2" ON COASTLINE TO AS MUCH AS 7-8" NEAR NH BORDER. BUT AVERAGE IS LOW ENOUGH TO KEEP AN ADVISORY GOING THERE. HEAVIEST SNOW SHOULD SHIFT INTO MERRIMACK VALLEY EARLY THIS AFTERNOON WHILE SNOWFALL RATES DECREASE BACK ACROSS CT VALLEY. STRONGEST LIFT IS HEADING QUICKLY FOR COAST BY MID AFTERNOON...SO WE THINK MANY LOCATIONS WILL SEE IMPROVING CONDITIONS BY 3 OR 4 PM EXCEPT FOR CAPE COD AND ISLANDS. MAIN CONCERN THEN BECOMES WIND. SURFACE LOW DEEPENING RAPIDLY OFF CAPE COD WILL CAUSE A RAPID INCREASE IN WINDS THROUGHOUT ALL OF REGION...BUT ESPECIALLY NEAR COAST. IF WE TAKE GFS SOUNDINGS FOR HYANNIS AND NANTUCKET AT FACE VALUE IT SHOWS A STRONG POTENTIAL OF 50-60KT GUSTS AS THIS DEEPENING OCCURS LATE THIS AFTERNOON AND EVENING. WE THINK THIS MAY BE A LITTLE HIGH...BUT WE HAVE ENOUGH CONFIDENCE TO ISSUE HIGH WIND WARNINGS AT THIS TIME. WIND ADVISORY WILL BE KEPT IN PLACE FOR S COAST...EVEN THOUGH CONFIDENCE ON 40KT GUSTS THERE IS LESS. ADVISORIES MAY ALSO NEED TO BE ISSUED FOR E MA COASTLINE BUT RIGHT NOW WE THINK WE WILL FALL SHORT OF CRITERIA THERE. CLEARING SHOULD WORK IN RAPIDLY THIS EVENING AS CROSS SECTIONS SHOW RAPID DRYING AND STRONG SUBSIDENCE...BUT WINDS WILL ONLY DIMINISH GRADUALLY UNTIL SYSTEM PULLS FARTHER OFFSHORE. LONG TERM (SATURDAY THROUGH THURSDAY)... OVERALL COLD AIR REMAINS IN PLACE OVER REGION THROUGH AT LEAST THURSDAY. WEAK RIDGE BUILDS OVER REGION SATURDAY IN WAKE OF DEPARTING STORM. SATURDAY NIGHT HEIGHTS BEGIN TO FALL AND WINDS BACK AS CYCLONIC FLOW BEGINS TO TAKE OVER. SHORTWAVES MOVE OVERHEAD THROUGH MONDAY WHILE AT THE SURFACE A DISORGANIZED LOW PRESSURE AREA MOVES ACROSS SOUTHERN QUEBEC TOWARD THE CANADIAN MARITIMES. COLD AIR ADVECTION ACROSS REGION COULD YIELD SHOWERS OVER OUTER WATERS CLIPPING CAPE AND ISLANDS. SURFACE HIGH PRESSURE BUILDS SOUTHEAST FROM CENTRAL CANADA...AND RESULTING N TO NW WINDS OVER CAPE COULD YIELD OCEAN EFFECT SNOW SHOWERS TUESDAY AND WEDNESDAY. RIDGING THROUGH THE COLUMN BUILDS OVER NEW ENGLAND THURSDAY...THEN REGION AWAITS NEXT POTENTIAL NOREASTER FOR FRIDAY. AVIATION... VFR FOR THE MOMENT...EXCEPT FOR MVFR CEILINGS NEAR NANTUCKET WHICH WILL SPREAD ONTO S COAST EARLY THIS MORNING. CONDITIONS WILL DETERIORATE RAPIDLY THIS MORNING TO IFR AS SNOW ARRIVES (THEN TO LIFR WITHIN 2 HOURS OF THAT)...CURRENTLY TIMED INTO CT VALLEY TOWARD SUNRISE AND BEFORE MID MORNING ALONG E MA COAST. CONDITIONS WILL LIFT TO MVFR THIS AFTERNOON AS HEAVIER SNOW SHIFTS OFFSHORE...THEN WE EXPECT RAPID IMPROVEMENT TO VFR BY EARLY THIS EVENING AS LOW PULLS OFF THE COAST. MARINE... WE WILL EXPAND STORM WARNINGS THIS AFTERNOON TO INCLUDE CAPE COD BAY AND NANTUCKET SOUND...AND MAINTAIN GALE WARNINGS ELSEWHERE AS WINDS INCREASE RAPIDLY BEHIND DEPARTING LOW. THERE IS STILL SOME QUESTION AS TO HOW FAST THE LOW WILL DEEPEN...IMPACTING WIND GUST POTENTIAL... BUT IT IS MORE LIKELY IT WILL OCCUR CLOSE ENOUGH TO CAPE COD RATHER THAN FARTHER OFFSHORE. WINDS AND SEAS SLOWLY DIMINISH OVERNIGHT AS SYSTEM PULLS FARTHER AWAY. FOLLOWED WNA WAVE GUIDANCE...HOWEVER GIVEN PREVAILING WEST TO SOUTHWEST WINDS SATURDAY AND SUNDAY...INCREASED SEAS IN BUZZARDS BAY. SMALL CRAFT ADVISORY CONDITIONS EXPECTED OVER THE WEEKEND FOR OUTER WATERS AND ALONG SOUTH COAST...ALL DUE TO WIND GUSTS TO 30 KTS AND ROUGH SEAS. WINDS AND SEAS SUBSIDE MONDAY AND TUESDAY. CLIMATE... FYI...RECORD DAILY SNOWFALL TOTALS FOR TODAY ARE AS FOLLOWS... KBOS... 4.6 INCHES IN 1978 KPVD... 3.0 INCHES IN 1995 KORH... 8.0 INCHES IN 1903 KBDL... 4.2 INCHES IN 1995 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAVY SNOW WARNING FOR CTZ002>004 UNTIL 4 PM FRIDAY. MA...HEAVY SNOW WARNING FOR MAZ002>004-008>012 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR MAZ005-006-013-014-026 UNTIL 5 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR MAZ007-015>019 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR MAZ020-021 FROM 4 PM FRIDAY TO 1 AM SATURDAY. ...HIGH WIND WARNING FOR MAZ022>024 FROM 4 PM FRIDAY TO 1 AM SATURDAY. NH...HEAVY SNOW WARNING FOR NHZ011 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR NHZ012-015 UNTIL 5 PM FRIDAY. RI...HEAVY SNOW WARNING FOR RIZ001 UNTIL 4 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR RIZ002>005 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR RIZ006>008 FROM 4 PM FRIDAY TO 1 AM SATURDAY. MARINE...GALE WARNING FOR ANZ230-233>237 FROM 1 PM FRIDAY TO 1 AM SATURDAY. ...STORM WARNING FOR ANZ231-232-250-254-255 FROM 1 PM FRIDAY TO 1 AM SATURDAY. && $$ SHORT TERM...NOCERA ma AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BUFFALO NY 920 AM EST FRI DEC 9 2005 .UPDATE... WILD MORNING AS THE NORTHERN LOW THAT PASSED JUST NORTH OF BUFFALO CREATED STRONG WINDS TO THE SOUTH OF THE CENTER. THIS COUPLED WITH AN AREA OF MODERATE SNOW BEHIND THE ASSOCIATED COLD FRONT PRODUCED WHITEOUT CONDITIONS AT TIMES. FORTUNATELY THE COASTAL LOW OFF NEW JERSEY WILL DEEPEN AND ZAP THE STRENGTH OF THE NORTHERN LOW. IMPROVEMENTS ARE EXPECTED WEST AND AREAS TO THE EAST WILL NOT EXPERIENCE THE SAME WIND STRENGTH AS THE WESTERN PART OF THE STATE DID. ADDITIONAL SNOW WILL THOUGH WILL ACCOMPANY THE COLD FRONT TO THE EAST AND THERE WILL BE SOME LAKE ENHANCEMENT SOUTHEAST OF BOTH LAKES INTO LATE AFTERNOON. EARLIER DISCUSSION REMAINS BELOW IN ITS ENTIRETY. && .SHORT TERM (TODAY THROUGH SUNDAY)... AS OF THIS WRITING...THE SURFACE LOW PROVIDING US WITH OUR SNOW THIS MORNING IS LOCATED OVER CENTRAL LAKE ERIE. IN ADVANCE OF THIS LOW...THE INITIAL BURST OF WARM ADVECTIVE SNOW HAS ALREADY ADVANCED CLEAR ACROSS WESTERN NY INTO LAKE ONTARIO AND THE NORTH COUNTRY...WITH A PRONOUNCED DRY SLOT NOW WORKING INTO FAR WESTERN NY/THE FINGER LAKES AS PER THE LATEST SATELLITE AND RADAR IMAGERY. BECAUSE OF THIS...MOST OF THE STEADY PCPN STILL UPSTREAM OF US IS MAINLY CONFINED TO AREAS NORTH OF THE SURFACE LOW TRACK...IN THE MID AND UPPER LEVEL DEFORMATION ZONE CURRENTLY LYING ACROSS SOUTHERN ONTARIO/LAKE HURON/LOWER MICHIGAN. THE MODELS ARE IN UNIVERSAL AGREEMENT ON THE TRACK OF THE LOW TODAY...WITH THE 00Z/06Z NAM...00Z GFS...AND RUC ALL TRACKING THE SURFACE WAVE NORTHEAST ACROSS THE NIAGARA PENINSULA/NIAGARA COUNTY...AND INTO LAKE ONTARIO THIS MORNING. SUCH A TRACK WILL KEEP THE AFOREMENTIONED AREA OF HEAVIER DEFORMATION ZONE SNOW LARGELY TO OUR NORTH AND WEST...THOUGH BY THE SAME TOKEN THERE WILL STILL LIKELY BE A 1-2 HOUR BURST OF HEAVIER SNOW AS THE TRAILING COLD FRONT WORKS ACROSS THE AREA THIS MORNING. IN TERMS OF ACCUMULATIONS TODAY...A GENERAL 1 TO 2 INCHES OF ADDITIONAL SNOW LOOK REASONABLE ACROSS THE AREA...OR A BIT LESS THAN OFFERED BY THE 00Z NAM. THE LOWEST AMOUNTS WILL LIKELY BE ACROSS THE GENESEE VALLEY AND FINGER LAKES REGION...WHILE SLIGHTLY HIGHER AMOUNTS WILL BE POSSIBLE SOUTHEAST OF THE LAKES AND EAST OF LAKE ONTARIO OWING TO LIMITED LAKE ENHANCEMENT/OROGRAPHIC EFFECTS. BECAUSE ACCUMULATIONS HAVE BEEN LIGHTER THAN EXPECTED SO FAR (GENERALLY 1-2")...AND THE FACT THAT WE ARE EXPECTING A BIT LESS SNOW TODAY COMPARED TO PREVIOUS FORECASTS...WE HAVE DECIDED TO DROP THE SNOW ADVISORY FOR ALL ZONES WITH THIS PACKAGE. THAT SAID...WHILE EVENT TOTAL SNOWFALL AMOUNTS WILL LIKELY BE LESS THAN ADVISORY CRITERIA...ANY UNTREATED ROADWAYS WILL STILL BE SNOW COVERED AND EXTREMELY SLIPPERY THIS MORNING. ANY ONGOING LAKE EFFECT ACTIVITY BEHIND THE LOW SHOULD HOLD ITS OWN UNTIL ABOUT 00Z TONIGHT SOUTHEAST OF BOTH LAKES...THEN A CRASHING INVERSION/DRYING BOUNDARY LAYER/WARMING TEMPS ALOFT WILL HELP END THE LAKE EFFECT...DURING THIS EVENING OFF OF LAKE ERIE AND BY MIDDAY SATURDAY OFF OF LAKE ONTARIO. WILL KEEP SCATTERED SNOW SHOWERS GOING THROUGH THOSE TIMES...THOUGH ACCUMULATIONS WILL BE VERY MINOR...IF ANY TONIGHT AND SATURDAY MORNING. OTHERWISE...SATURDAY SHOULD TURN OUT TO BE A PARTLY SUNNY AND DRY DAY FOR THE AREA...THOUGH IT WILL ALSO TURN OUT TO BE RATHER WINDY AS A STIFF/DEEP SOUTHWEST FLOW WILL BE IN PLACE. AS A RESULT...EVEN THOUGH HIGHS WILL BE IN THE LOWER TO MID 30S...IT WILL DEFINITELY NOT FEEL THAT WARM. FOR SATURDAY NIGHT AND SUNDAY...SURFACE LOW PRESSURE TO OUR NORTH WILL GRADUALLY EDGE SOUTHEASTWARD TOWARDS OUR AREA...EVENTUALLY SWINGING A COLD FRONT THROUGH THE AREA ON SUNDAY WITH A LIKELIHOOD OF SNOW SHOWERS. AS A RESULT...WE HAVE GRADUALLY INCREASED POPS FROM NORTHWEST TO SOUTHEAST THROUGH MID SUNDAY MORNING...THEN HAVE GONE LIKELY EVERYWHERE THE REST OF SUNDAY WITH THE COLD FROPA. ONE MESOSCALE FEATURE TO WATCH DURING THIS LATTER PERIOD: BOTH THE NAM AND GFS INDICATE THAT 850 MB TEMPS WILL DROP TO THE -8C TO -10C RANGE FOR THE LATTER HALF OF SATURDAY NIGHT...ALONG WITH A WEAKENING INVERSION/DEEPENING MOISTURE THROUGHOUT THE ATMOSPHERIC COLUMN. WITH A DEEP SOUTHWEST FLOW STILL IN PLACE...THERE IS THE POTENTIAL FOR LAKE EFFECT SNOWS TO REDEVELOP NORTHEAST OF THE LAKES LATER SATURDAY NIGHT/SUNDAY MORNING IN ADVANCE OF THE APPROACHING COLD FRONT...AND THIS WOULD AFFECT THE BUFFALO AND WATERTOWN AREAS. FOR NOW...HAVE RAISED POPS TO THE HIGH CHANCE CATEGORY FOR THESE AREAS FOR LATER SATURDAY NIGHT...BUT THIS TIME PERIOD WILL HAVE TO BE CLOSELY MONITORED BY SUBSEQUENT SHIFTS. && .LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)... THE WINTRY PATTERN WILL CONTINUE THROUGH THIS PERIOD AS A LONG WAVE UPPER TROUGH PERSISTS ACROSS EASTERN CANADA AND THE GREAT LAKES REGION. 850 MILLIBAR TEMPERATURES ARE FORECAST TO AVERAGE AROUND MINUS 15C THROUGH AT LEAST WEDNESDAY THEN JUST A LITTLE WARMER THURSDAY AS A RIDGE EDGES IN FROM THE WEST. NO MAJOR STORMS ARE FORESEEN AT THIS TIME BUT THE NORTHWEST FLOW ACROSS THE LAKES WILL LIKELY PRODUCE SOME SCATTERED LAKE EFFECT SNOWS. && .AVIATION... THE INITIAL BATCH OF WARM ADVECTION SNOW SWEPT ACROSS WESTERN NEW YORK BETWEEN 03Z AND 07Z...LOWERING CIGS AND VSBYS TO IFR AND EVEN LIFR AT TIMES. A SEMI DRY SLOT HAS FOLLOWED HOWEVER...SO CONDITIONS WILL OCCASIONALLY IMPROVE TO MVFR THROUGH 12Z IN PATCHY SNOW. KART WILL FOLLOW A SIMILAR TREND...ALBEIT DELAYED A FEW HOURS. A COLD FRONT WILL THEN SWEEP ACROSS THE REGION BETWEEN 13Z AND 17Z WITH A BURST OF SNOW AND ASSOCIATED IFR CONDITIONS...BUT ALL WILL IMPROVE TO VFR THIS AFTERNOON. WINDS WILL VEER TO SOUTH AND SOUTHWEST EARLY THIS MORNING THEN SHIFT TO WEST AND NORTHWEST FOLLOWING THE FROPA. && .MARINE... WE WILL HAVE A VERY COMPLEX WIND SCENARIO EARLY THIS MORNING AS INITIAL LOW PRESSURE NEAR DETROIT AT 06Z MOVES EAST TO LAKE ONTARIO BY 12Z AND THEN WEAKENS...GIVING WAY TO A COASTAL STORM OFF NEW JERSEY. THIS PATH WILL ALLOW WINDS TO BECOME SOUTHERLY AND INCREASE ON THE LAKE ERIE WATERS BUT THEY WILL TEND EASTERLY OVER LAKE ONTARIO. THE TRAILING COLD FRONT WILL THEN SWEEP ACROSS LAKE ERIE THIS MORNING AND LAKE ONTARIO BY EARLY AFTERNOON. WINDS WILL INCREASE INTO THE 15 TO 25 KNOT RANGE THIS AFTERNOON AND EVENING BEFORE LIGHTENING UP ONLY SLIGHTLY EARLY SATURDAY. THE WESTERLY GRADIENT WILL INCREASE AGAIN DURING SATURDAY AS DEEPENING LOW PRESSURE MOVES ACROSS NORTHERN ONTARIO. WE WILL ISSUE SMALL CRAFTS TO ACCOUNT FOR THIS SCENARIO FOR ALL NEARSHORE WATERS THROUGH 4 PM SATURDAY...BEGINNING EARLY THIS MORNING ON LAKE ERIE AND EARLY THIS AFTERNOON ON THE EASTERN SHORE OF LAKE ONTARIO AND ST. LAWRENCE RIVER. && .BUF WATCHES/WARNINGS/ADVISORIES... .NY...NONE. .MARINE....SMALL CRAFT ADVISORIES ALL NEARSHORES THROUGH SATURDAY AFTERNOON. $$ UPDATE...SAGE SHORT TERM...JJR LONG TERM...SAGE AVIATION/MARINE...SFM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1010 AM CST FRI DEC 9 2005 .UPDATE HIGHS TODAY STILL SEEM ON TRACK...MAY NOT SEE HIGHS ACROSS THE EAST UNTIL LATE THIS AFTERNOON OR INTO THE EARLY EVENING HRS. RUC NOT SHOWING REAL GOOD WAA UNTIL LATER THIS AFTERNOON ACROSS THE EAST. FIXED CLOUD COVER TO ACCOUNT FOR STRATUS DECK MOVING ACROSS CWA. CLEARING LINE CROSSING MISSOURI RIVER AND WILL SLIDE ACROSS THE CWA TODAY. SHOULD SEE SOME SUN THIS AFTERNOON ACROSS THE EAST BUT HIGHER CLOUDS WILL QUICKLY MOVE IN FROM THE NORTHWEST SO SUNSHINE WILL BE LIMITED. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ TMT sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 933 AM CST FRI DEC 9 2005 .UPDATE... QUICK UPDATE THIS MORNING TO ACCOUNT FOR CURRENT CLOUD TRENDS. CLOUD DECK AROUND 850 MB CLOUDS CONTINUES TO STREAM NORTH ACROSS SOUTH AND CENTRAL TEXAS...AND IS NOW FLIRTING WITH MY SOUTHEAST COUNTIES. LATEST RUC SEEMS TO HAVE HAD A DECENT HANDLE ON IT AND WILL USE IT AS A ROUGH GUIDANCE FOR THE REST OF TODAY. HAVE INCREASED CLOUD COVER TODAY ACROSS MAINLY KIMBLE...MASON...AND SAN SABA COUNTIES...AND LOWERED AFTERNOON HIGHS IN THOSE SAME AREAS. IF CLOUD DECK HANGS IN TOUGH THROUGH THE DAY...INSTEAD OF COMING IN FOR AWHILE AND THEN BREAKING UP BY LATE IN THE AFTERNOON...MAY HAVE TO KNOCK TEMPS DOWN EVEN MORE. && .PREV DISCUSSION... (ISSUED 516 AM CST FRI DEC 9 2005) AVIATION... EXPECT VFR CONDITIONS...WITH SOUTH WINDS IN THE 5 TO 10 KT RANGE...TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR THE NEXT 24 HOURS. 23/HUBER PREV DISCUSSION... (ISSUED 306 AM CST FRI DEC 9 2005) SHORT TERM... THIS MORNING...UPPER LOWS SITUATED OVER THE GREAT LAKES REGION AND JUST OFF THE CALIFORNIA COAST WITH CLEAR SKIES OVER THE CWA. AFTER ANOTHER COLD START TO THE MORNING...AFTERNOON TEMPS WILL AVERAGE AROUND 15 DEGREES WARMER THAN YESTERDAY. UPPER DISTURBANCE FORMING OVER THE CENTRAL PLAINS TODAY WILL MOVE QUICKLY EAST AND WILL BE ABSORBED INTO THE MAIN UPPER FLOW...ONLY EFFECT ON OUR WEATHER WILL BE A WEAK COLD FRONT PUSHING THROUGH THE AREA ON SATURDAY AFTERNOON. LONG TERM... UPPER RIDGE WILL BUILD INTO OUR AREA ON SUNDAY AHEAD OF THE UPPER LOW MOVING INTO CALIFORNIA. NORTH WINDS WILL SHIFT BACK TO THE SOUTH DURING THE DAY ON SUNDAY WITH AFTERNOON TEMPS INTO THE 60S. UPPER LOW OVER CALIFORNIA WILL BE SHEARED INTO THE UPPER FLOW MIDWEEK WITH ANOTHER WEAK COLD FRONT PUSHING THROUGH THE AREA ON TUESDAY. MORE SIGNIFICANT COLD FRONT TO PUSH THROUGH THE AREA DURING THE DAY ON THURSDAY WITH GOOD PREFRONTAL WARMING ON WEDNESDAY WELL INTO THE 60S. AT THIS TIME...WITH LIMITED MOISTURE TO WORK WITH IN OUR AREA ANY RAINFALL CHANCES LOOK SLIM. SJT WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07 tx AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE LOUISVILLE KY 1140 AM EST FRI DEC 9 2005 .UPDATE... UPDATED FORECAST FOR CLOUDS AND HIGH TEMPERATURES TODAY. SATELLITE AND SURFACE OBS INDICATE THAT CLOUDS WRAPPED AROUND THE UPPER LOW TO OUR NORTH IS MAKING ONLY SLOW PROGRESS TO THE EAST. THE CLOUDS WERE ALSO ADVANCING SOUTHEAST ACROSS CENTRAL KENTUCKY. WILL KEEP CLOUDS AND A MENTION OF FLURRIES IN FORECAST THROUGH MUCH OF THE AFTERNOON. WILL BRING CLOUDS SOUTH ACROSS MUCH OF SOUTH CENTRAL KENTUCKY. THE ONLY AREA TO SEE SIGNIFICANT SUN THIS AFTERNOON WILL BE OVER THE SOUTHWEST NEAR AND SOUTHWEST OF BWG. TEMPERATURES THIS MORNING STARTED OUT COLD AND WITH CLOUDS HAVE TRIMMED HIGH TEMPERATURES A FEW DEGREES OVER PREVIOUS FORECAST. OTHERWISE NO CHANGES. SCHOLZ PREVIOUS DISCUSSION... .SHORT TERM (TODAY-TONIGHT)... ...VERY COLD OVER NEXT 24 HOURS... IN THE WAKE OF POTENT UPPER TROF BARRELING EASTWARD OVER IN/OH... WESTERLIES HAVE BEEN GUSTY OVER THE CWA...G25-30KTS COMMON DURING THE PAST FEW HOURS. WIND CHILLS INTO SINGLE DIGITS TO NEAR ZERO THROUGH THE PRE-DAWN HOURS. GRADIENT LOOKS TO RELAX CONSIDERABLY THIS MORNING PER BUFKIT SOUNDINGS AS SFC HIGH MOVES INTO THE REGION. THERE WERE SOME BLOWING SNOW ISSUES OVER INDIANA EARLIER...THOUGH WITH WINDS SETTLING DOWN THIS WILL BECOME LESS OF AN ISSUE FOR SRN INDIANA. LOW STRATUS REMAINS OVER MUCH OF THE CWA AS OF 06 UTC...SOME BREAKS ALONG/WEST OF I-65. EMBEDDED WITHIN...A RATHER PERSISTENT BAND OF -SHSN/FLURRIES HAS DEVELOPED FROM BRECKINRIDGE COUNTY OVER INTO THE FTK/LOU/FFT AREAS...PRODUCING SOME TRACE ACCUMULATIONS. BUFKIT SOUNDINGS INDICATE SHALLOW LAYER OF STEEP LAPSE RATES INTO THE -10 TO -15C LEVEL PERSISTING INTO THE MORNING HOURS...SO WILL CONTINUE TO MENTION SCT LIGHT SNOW SHOWERS OR FLURRIES. THERE HAVE BEEN REPORTS OF ACCIDENTS DUE TO REFREEZE FROM YESTERDAYS PCPN... SOMETHING THAT MORNING COMMUTERS WILL HAVE TO KEEP IN MIND... ESPECIALLY IN PARKING LOTS AND UNTREATED SURFACES. CLOUD FCST WILL BE CHALLENGING. RUC/NAM 925MB RH FIELDS DEPICT THE CURRENT CLOUD DISTRIBUTION WELL...AND INDICATE CLEARING FROM SW-NE THROUGHOUT THE DAY WHICH SEEMS REASONABLE...GIVEN RELATIVELY SHALLOW NATURE OF THE MOISTURE. THOUGH WITH BOUNDARY LAYER WINDS SWITCHING FROM W TO N/NW TODAY...THAT MAY SLOW THE PROGRESSION OF CLEARING SUCH THAT PARTS OF SE IND INTO LEX/BLUEGRASS COUNTIES MAY STAY CLOUDY LONGER. TEMPERATURES ARE ANOTHER CONCERN. WITH 850MB TEMPS NEAR -10C PER RUC ANALYSIS AND SDF ACARS SOUNDINGS...A VERY COLD DAY IS IN STORE ESPECIALLY AREAS THAT WOULD HAVE MORE CLOUD COVER. LEANED TOWARD RAW NAM/MOS NUMBERS. SNOWCOVER OVER SRN IND WILL HAVE A DOWNWARD INFLUENCE ON TEMPS TONIGHT...THOUGH THERE COULD BE SOME HIGH CLOUDS AFTER MIDNIGHT AHEAD OF ANOTHER UPPER SHORTWAVE APPROACHING. WON'T GO AS COLD AS RAW NAM DATA TONIGHT...BUT SOME UPPER SINGLE DIGIT READINGS POSSIBLE IN SRN IND...WITH LOW/MIDDLE TEENS ELSEWHERE IN THE CWA. CS .LONG TERM (SATURDAY-THURSDAY)... .SATURDAY... EXPECT A TRANQUIL DAY AS LOWER OHIO VALLEY WILL REMAIN BETWEEN SYSTEMS. HIGH PRESSURE ACROSS THE SOUTHEASTERN STATES WILL PROVIDE SUNNY SKIES WITH LIGHT WINDS...ALBEIT WITH STILL CHILLY TEMPERATURES. LIGHT WINDS IN THE MORNING WILL BECOME SOUTHWEST IN THE AFTERNOON AS WINDS INCREASE A BIT AHEAD OF A SURFACE TROUGH MOVING SOUTH ACROSS THE UPPER MIDWEST. .SUNDAY... AS A REX BLOCK SHARPENS ACROSS THE WEST COAST...TROUGH WILL AMPLIFY ALONG THE MISSISSIPPI VALLEY AS JET STREAM ENERGY DROPS SOUTHWARD ACROSS CENTRAL US. SURFACE TROUGH ASSOCIATED WITH LOW PRESSURE MOVING ACROSS THE GREAT LAKES WILL PUSH A REINFORCING COLD SURGE DURING THE DAY ON SUNDAY. LOW LEVEL MOISTURE WILL INCREASE SUNDAY AND CANNOT RULE OUT CHANCE OF LIGHT SNOW DURING THE DAY AND SUNDAY NIGHT. CHANCES OF SNOW MAY CONTINUE THROUGH EARLY MONDAY AS ISENTROPIC LIFT INCREASES ACROSS AN ELEVATED FRONT EXPECTED TO DEVELOP ACROSS KENTUCKY. .TUESDAY THROUGH THURSDAY... THIS PERIOD MAY BE THE START OF AN UPPER AIR TRANSITIONAL PERIOD AS REX BLOCK ACROSS WEST COAST BREAKS DOWN DUE TO WESTERLIES UNDERCUTTING THE RIDGE. TEMPERATURES ACROSS THE LOWER OHIO VALLEY...RUNNING AROUND 13 DEGREES BELOW NORMAL FOR THE MONTH OF DEC SO FAR...MAY MODERATE AS PERSISTENT COLD TROUGH EASES AND MOVES EAST TOWARDS NEW ENGLAND. WITH A SPLIT FLOW PATTERN MOVING EAST ACROSS THE PLAINS...THE LOWER OHIO VALLEY LOOKS STORM FREE THIS PERIOD. WILL KEEP JUST A CHANCE OF PRECIP IN FORECAST WEDNESDAY AS A WEAK DISTURBANCE MOVES ACROSS UPPER OHIO VALLEY. JSD && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 1150 AM EST FRI DEC 9 2005 .SYNOPSIS...LOW PRESSURE APPROACHING FROM THE EASTERN GREAT LAKES WILL REDEVELOP OFF THE SOUTHERN NEW ENGLAND COAST TODAY. THE LOW IS EXPECTED TO RAPIDLY INTENSIFY AS IT MOVES ACROSS THE GULF OF MAINE THIS EVENING. THE LOW WILL THEN TRACK SOUTH OF NOVA SCOTIA LATE TONIGHT. HIGH PRESSURE WILL BUILD ACROSS THE REGION ON SATURDAY THEN A TROUGH OF LOW PRESSURE WILL APPROACH THE AREAS ON SUNDAY. && .SHORT TERM (REST OF TODAY THROUGH THURSDAY NIGHT)... CURRENT HEADLINES TO REMAIN IN PLACE THIS AFTERNOON AND TONIGHT. MAIN ADJUSTMENT FOR THE UPDATE WAS TO INCREASE SOME SNOW ACCUMULATION AMOUNTS ACROSS THE NORTH CENTRAL ZONES AS WELL AS PORTIONS OF DOWNEAST BASED ON RADAR TRENDS AND NEW 12Z QPF GUIDANCE FROM THE NAM/GFS WHICH IS SUPPORTED BY THE LATEST RUC GUIDANCE. NO OTHER CHANGES NEEDED. && .PREVIOUS DISCUSSION... (ISSUED 240 AM EST FRI DEC 9 2005) SYNOPSIS...LOW PRESSURE APPROACHING FROM THE EASTERN GREAT LAKES WILL REDEVELOP OFF THE SOUTHERN NEW ENGLAND COAST TODAY. THE LOW IS EXPECTED TO RAPIDLY INTENSIFY AS IT MOVES ACROSS THE GULF OF MAINE THIS EVENING. THE LOW WILL THEN TRACK SOUTH OF NOVA SCOTIA LATE TONIGHT. HIGH PRESSURE WILL BUILD ACROSS THE REGION ON SATURDAY THEN A TROUGH OF LOW PRESSURE WILL APPROACH THE AREAS ON SUNDAY. SHORT TERM (TODAY THROUGH TONIGHT)... STILL DIFFS BETWEEN THE NAM AND GFS THOUGH NAM HAS BEEN MOST CONSISTENT W/ GFS GRADUALLY TRENDING FURTHER N LAST FEW RUNS... USED A BLEND FOR POPS/QPF WHICH RESULTED IN MINIMAL WARNING CRITERIA COASTAL ZNS W/ ADV CRITERIA FOR INTERIOR DOWNEAST ZNS... SO HAVE A HVY SNW WRNG ZNS 29/30 AND A SNW ADV ZNS 15>17 FOR THIS AFTN INTO TNGT. SYSTEM A FAST MOVER WHICH SHOULD PRETTY MUCH BE MOVING OUT OF THE AREA BY MDNGT SO NOT XPCTNG THIS TO BE A MAJOR STORM ATTM... LGT SNOWS SHOULD REACH FAR NRN MAINE BUT GRADIENT OF HEAVIEST PRECIP STILL XPCTD TO BE QUITE SHARP FROM DOWNEAST INTO CENTRAL ZNS SO ANY ACCUMS UP N SHOULD BE QUITE LGT... LONG TERM (SATURDAY THROUGH THURSDAY)... NO SIGNIFICANT CHANGES IN THE LONG TERM. HIGH PRESSURE MOVES ACROSS THE STATE SATURDAY IN RESPONSE TO UPSTREAM UPPER TROUGH MOVING THROUGH CENTRAL CANADA. WARM AIR ADVECTION CLOUDS AND SNOW SHOWERS POSSIBLE LATE SATURDAY INTO SUNDAY AS LOW PRESSURE TRACKS NORTHWEST OF THE STATE. AS UPPER TROUGH MOVES OVER THE EAST...COLD FRONT WILL MOVE THROUGH THE STATE WITH POSSIBLE SNOW SHOWERS ON SUNDAY. MODELS INDICATING LOW PRESSURE TO DEVELOP OFF THE EAST COAST IN ADVANCE OF THE COLD FRONT BUT LOW TO REMAIN TO OUR EAST AS IT TRACKS THROUGH NOVA SCOTIA. LOOKING FARTHER OUT... STORM TRACK REMAINS SOUTH OF THE AREA WITH COLD DRY WEATHER THE RULE. AVIATION... VFR TO START AT ALL TAF SITES ERLY THIS AM W/ CONDS DETERIORATING TO IFR AT KBGR BY ERLY AFTN W/ MVFR XPCTD AT THE REMAINING SITES BY LATER AFTN... && MARINE... HAVE OPTED TO GO W/ A GLW FOR A PERIOD FROM THIS EVE TIL ERLY SAT AM BASED ON SLIGHTLY FURTHER N TRACK AND TO MATCH UP BETTER W/ GYX LONG TERM: POSSIBLE SCA CONDITIONS SATURDAY NIGHT IN ADVANCE OF COLD FRONT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...HEAVY SNOW WARNING FOR MEZ029-030 UNTIL 3 AM SATURDAY. ...SNOW ADVISORY FOR MEZ015>017 UNTIL 3 AM SATURDAY. MARINE...GALE WARNING FOR ANZ050 FROM 8 PM FRIDAY TO 4 AM SATURDAY. $$ UPDATE...FITZSIMMONS SHORT TERM/MARINE...KHW LONG TERM/MARINE...FOSTER AVIATION...SMF/KHW me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 427 PM EST FRI DEC 9 2005 ...BRIEF SEVERE STORM E MA RI IS ENDING RAPIDLY NOW... M1...347 PM. GUSTS 69-72 KTS BUZ BAY TO 44029...CAPE WIND TOWER REPORTED (UNOFFICIAL) WEST WIND 64KTG81KT AT 3PM. WIND INSTRUMENT 20M ELEVATED...ABV THE NORMAL 10M OFFICIAL. SITING LIKENS TO A CMAN ELEVATED OB. WE HAVE LITTLE DOUBT 55 TO 70 KT NEAR SFC WINDS ALREADY OBSERVED. HEARING MOORINGS SEPARATING. M2...424 PM DANGEROUS CONDS QUITTING ABRUPTLY NEXT 1 HR. NEAR BLIZ ALREADY ENDED BOS. HEARD OF MINOR COASTAL FLOODING BUZ BAY EARLIER. TIDES HAS 2-3FT SURGE FOR 1 HR IN EXCESSIVE PRES FALL/RIDE COUPLET ASSOCIATED WITH 2 HR WIDE FURY THAT DEVELOPED PER EXCT NCEP MODEL COMBO NAM/GFS LEADING UP TO THIS EVENT. MANY REPORTS OF TREES DOWN ON CAPE COD. FULL AFD FROM ELEANOR AND NEAL SHORTLY REMAINDER BLO 158 PM. .SHORT TERM (REST OF TONIGHT)... WILD WINTER WEATHER HERE IN SNE...WITH SFC LOW UNDERGOING BOMOGENESIS IN RI SND AT 130 PM. SFC LOW WL MV QUICKLY E WITH LATEST ANALYSIS INDICATING 17 MB PRES DROP IN PAST 3 HRS CENTERED OVR ACK SND! SIGNIFICANT WND SHIFT BEHIND THIS LOW WITH WNDS GUSTING TO 55 MPH ACRS ERN LI AND INTO CSTL RI. IN ADDITION BUOY S OF LI GUSTING TO 58 KTS! THUS...HV EXPANDED WND ADV EWD INTO EAST COASTAL MA...INCLUDING BOSTON...CAPE ANN AND PYM COUNTY. STGST WNDS RI CST...INCLUDING BID AND EWD ACRS S.CST OF MA. IN ADDITION...VIGOROUS COMMA HEAD DEVELOPING OVR ERN CT/RI AND ERN MA IN RESPONSE TO SIGNIFICANT HEIGHT FALLS WITH UPPER LOW. GOOD CSI BANDING HAS MATERIALIZED WITH SVRL RPTS OF THUNDER SNOW ACRS THIS AREA. THIS CONVECTIVE BAND WL YIELD A QUICK 3-5 INCHES OF SNFL IN NE CT/NW RI AND E OF ORH IN MA...INCLUDING HILLSBORO CNTY. FARTHER SE INTO I95 CORRIDOR...MIXED PRECIP WL CHANGE TO SN WITH AN ADDITIONAL 2-4 INCHES OF ACCUMULATIONS BEFORE BACK EDGE OF PRECIP MVS OFSHR. STRONG WINDS WILL COMBINE WITH A CHANGEOVER OF SN TO YIELD NEAR WHITE OUT CONDITIONS FROM NOW (2 PM) TIL 4-5 PM IN THE PVD-BOS CORRIDOR AND LKLY TIL 6-7PM SE OF I95. WOW...WHAT A STORM! NOCERA .PREVIOUS DISCUSSION... (ISSUED 1100 AM EST FRI DEC 9 2005) ..MESOSCALE CONVECTIVE BAND OF SNOW DEVELOPING IN LOWER CT VALLEY TO SOUTHERN NH... MESO/NEAR TERM UPDATE... 15Z MESOANALYSIS INDICATES A COASTAL FRONT EXTENDING FROM ISLIP NY NORTHEAST ALONG LONG ISLAND...NEAR COASTAL RI...NORTHEAST TO NEW BEDFORD...NORTH TO BEVERLY. ALSO...A SURFACE TROF IS FORMING FROM THE LOW CENTER SOUTH OF ISLIP...NORTHWARD PAST NORTH ADAMS MA. 40 KM NAM SHOWS STRONG FRONTOGENESIS ALONG THESE 2 FEATURES FROM 15Z TO 18Z...AS THE LOW MOVES EAST. KALY RADAR SHOWING A DEVELOPING BAND OF HEAVY SNOW WITH 30 TO EVEN 40 DBZ REFLECTIVITY...MESOSCALE CONVECTIVE BAND....UNDER SURFACE TROF AND WHERE SECONDARY BAND OF STRONG FRONTOGENESIS WAS INDICATED. THUNDERSNOW REPORTED IN CHICOPEE AT 1050 AM...1/4SM S+ AT HFD...BAF...CEF AND AQW. KEENE NH REPORTS 10 INCHES OF SNOWFALL SO FAR. AT THIS TIME...THIS HEAVY SNOW BAND IS EXPECTED TO MOVE GRADUALLY EASTWARD ACROSS MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE THROUGH EARLY THIS AFTERNOON. SNOWFALL RATES OF 1 TO 2 INCHES AN HOUR...AND ISOLATED 3 INCH PER HOUR SNOWFALL...ARE EXPECTED UNDER 30 TO 40 DBZ REFLECTIVITY. FOR COASTAL SOUTHERN NEW ENGLAND...KBOX RADAR PICKING UP ON BRIGHT BANDING...SOME MELTING OCCURRING ALOFT WITH REPORTS OF SLEET...RAIN ..AND FREEZING RAIN IN SOUTH COASTAL MA AND COASTAL RI. MIX TO RAIN LINE WAS ALONG A KINGSTON...PVD...PYM TO NEAR BVY LINE. COASTAL FRONT MAY PULL INLAND SOME OVER NEXT FEW HOURS. MIX SUPPORTS KEEPING WINTER WEATHER ADVISORIES AS THEY ARE AT THIS TIME. MARINE... MSAS INDICATING RAPID SURFACE PRESSURE FALLS OF UP TO 9 MB IN 3 HOURS...AND TIGHTENING GRADIENT. PLAN TO MENTION GUSTS TO 55 KT IN OUTER COASTAL WATERS...WHERE STORM WARNINGS ARE ALREADY IN EFFECT. NBELK PREVIOUS DISCUSSION... (ISSUED 920 AM EST FRI DEC 9 2005)... MESO/SHORT TERM UPDATE (REST OF TODAY)... COMPLEX WINTER SCENARIO UNFOLDING THIS AM...ESPECIALLY CAPE COD CANAL TO I95 CORRIDOR WHERE CSTL FNT BEGINNING TO DVLP. PARENT SFC LOW OVR LK ONTARIO BEGINNING TO WEAKEN/FILL...WHILE CSTL LOW JUST E OF NJ BEGINS TO INTENSIFY WITH SIGNIFICANT PRES FALLS CENTERED JUST S. OF MONTAUK ON THE ORDER OF -8 MBS DURING THE PAST 3 HRS. THESE PRES FALLS WL GRADUALLY BACK SFC WNDS TO N-NE OVR THE AREA AS THE MORNING PROGRESSES...WHICH WL RETARD THE N MVMNT OF THE CSTL FNT AND MIXED PRECIP LINE. THIS IS APPARENT IN THE 14Z SFC OBS...WITH SE WND AT BID AND NE WND AT GON AND WST. THE RESULT HERE IS FOR SUBFREEZING SFC LYR TO BE DELAYED MVG NWD FM CAPE COD CANAL TO I95. FURTHER COMPLICATING THIS AREA...IS THAT SUFFICIENT WARMING/MELTING IS OCCURRING ABV THE SFC LYR (PER STG SE INFLOW ON KBOX VAD WND PROFILE) ACRS THIS AREA FOR SN TO CHANGE TO SLEET AND OR FREEZING RN...AS WST AND GON RPTG -FZRA ANS SVRL SPOTTER RPTG SLEET. ALSO...KBOX COMPOSITE RADAR IMAGERY PICKING UP ON THIS WELL...WITH HIGH REFLECTIVITY OVR NARRAGANSETT BAY INDICATING SLEET. SO CURRENT FCST OF RN-SN LINE TRAVERSING NWWD INTO I95 CORRIDOR AND PSSBLY AS FAR NW AS I495 LKS GD. HWR...GIVEN LATEST TRENDS/CSTL FNT DVLPMNT AND STG PRES FALLS...SUBFREEZING SFC LYR WL BE DELAYED MVG NWD AND WL YIELD MORE OF A WINTRY MIX OF FZRA AND SLEET FM CAPE COD CANAL INTO I95. THUS...WL UPDATED WX GRIDS TO REFLECT MIXED PTYPE TRANSITION...RATHER THAN A CLEAN PTYPE CHANGE FM SN TO RN. INLAND...ESPECIALLY N OF THE MASS TURNPIKE AND NW OF I495 IT IS FAIRLY STRAIGHT FORWARD...WITH PTYPE REMAINING ALL SNOW. NO CHANGES TO SNOW ACCUMULATIONS AT THE MOMENT. ALTH...WL HV TO WATCH TRENDS OF CSTL FNT ALONG WITH STG PRES FALLS OFF THE S.CST. IF CSTL FNT REMAINS FARTHER S...BLYR WRMG MAY BE TOO MARGINAL FOR A CHANGEOVER AND STG UPWARD VERTICAL MOTION MAY BE ABLE TO COMPENSATE VIA DYNAMICAL AND DIABATIC COOLING PROCESSES. THEREFORE...COULD HAVE LESS MIXING IN FROM I495 TO I95 YIELDING HIER SN TOTALS. WL JUST HV TO MONITOR TRENDS AND AWAIT 12Z MDL GUID. NOCERA PREVIOUS DISCUSSION... (ISSUED 500 AM EST FRI DEC 9 2005) SHORT TERM (TODAY)... MESO DISCUSSION AND 06Z MODEL UPDATE... SNOW HAS MADE IT INTO NYC AND JUST STARTED IN HARTFORD AS WELL AS BERKSHIRES AND MONADNOCKS. KBOX RADAR SHOWS AN INITIAL BAND OF SNOW FROM MANCHESTER TO CAPE ANN AND OFFSHORE WHICH FOR MOST PART IS ALOFT...BUT IT IS GIVING A QUICK SHOT OF SNOW TO SOUTHERN NH. YOU CAN SEE THE DRY AIR AT LOWER LEVELS VERY WELL ON KBOX RADAR TOO... COVERING MUCH OF EASTERN MA AND RI. THIS WILL SLOWLY MOISTEN DURING NEXT COUPLE OF HOURS AND WE EXPECT SNOW TO REACH WORCESTER AND PROVIDENCE BY 7 AM AND BOSTON AROUND 8 AM OR SO. MODELS ARE TRENDING CLOSER WITH EACH RUN. 06Z NAM IS NOW A BIT FARTHER S WITH ITS LOW TRACK...NOW FROM MONTAUK POINT TO CAPE COD BAY WITH GFS HOLDING FIRM ON ITS TRACK S OF NANTUCKET. OTHER MESOSCALE MODELS INCLUDING 06Z RUC AND 06Z 10KM BOX ETA PREFER A TRACK CLOSER TO NAM...BUT THIS JUST SEEMS A BIT TOO FAR N TO US. ONE THING WE NOTICED IS NAM IS STILL A BIT SLOWER...AND BRINGS BEST LIFT INTO SOUTHERN NEW ENGLAND FROM MID MORNING INTO MID AFTERNOON...SO WE ARE STILL ON TARGET FOR 1-2"/HR SNOWFALL RATES...ESPECIALLY FOR HARTFORD TO WORCESTER AND LAWRENCE CORRIDOR WHERE SNOWFLAKE PRODUCTION WILL BE MAXIMIZED. WE HAVE SOME CONCERN THAT THIS STRONG LIFT MAY BE ABLE TO COMPENSATE ENOUGH FOR MARGINALLY WARM LOW LEVEL TEMPERATURES IN BOSTON AREA. IT STILL APPEARS WARM ENOUGH FOR A CHANGE TO RAIN IN PROVIDENCE AND SE MA. BOSTON MAY VERY WELL END UP SEEING MORE OF A MIX AS OPPOSED TO A CHANGE TO RAIN SHOULD NAM VERIFY...BUT A PROLONGED SE WIND USUALLY KILLS THE SNOWFLAKES IN BOSTON. ONE THING THAT HAS BEEN IMPRESSIVE SO FAR IS WHAT'S BEEN GOING ON UPSTREAM ACROSS MID ATLANTIC...ESPECIALLY FROM WASHINGTON DC INTO PA WHERE THERE HAVE BEEN MANY REPORTS OF 1-2"/HR SNOWFALL RATES AND EVEN THUNDER! THIS SHOULD ALL COME OUR WAY LATER THIS MORNING AND EARLY THIS AFTERNOON. JWD PREVIOUS DISCUSSION... (ISSUED 335 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH TONIGHT)... WE ARE KEEPING ALL WARNINGS AND ADVISORIES IN PLACE FOR SNOW TODAY... BUT WILL TRIM AMOUNTS DOWN SLIGHTLY NEAR I-95 CORRIDOR WHICH SHOULD SERVE AS OUR TRANSITION ZONE. TOTALS ACROSS INTERIOR LOOK GOOD. WE WILL ALSO UPGRADE THE HIGH WIND WATCH FOR CAPE COD AND THE ISLANDS TO A HIGH WIND WARNING. LEADING EDGE OF SNOW IS CURRENTLY WORKING THROUGH CENTRAL NY AND EASTERN PA...NOTE HOW QUICKLY VISIBILITIES DROP TO 1/2SM OR LESS AS SNOW BEGINS! ALTHOUGH WE HAVE PLENTY OF LOW LEVEL DRY AIR TO OVERCOME...IT WON'T TAKE LONG TO SATURATE THE COLUMN WITH SUCH A POTENT SYSTEM ON OUR DOORSTEP. WE EXPECT SNOW TO BEGIN IN CT VALLEY AROUND SUNRISE (PROBABLY 6 AM) AND QUICKLY HEAD TO E MA COAST DURING MORNING RUSH HOUR (8-9 AM)...PLUS/MINUS AN HOUR OR TWO. 00Z NAM STILL FARTHEST N OF MODELS THIS MORNING...BUT 00Z GFS CONTINUES ITS TREND OF EDGING FARTHER N WITH EACH RUN...NOW TAKING SECONDARY LOW JUST SE OF NANTUCKET. IT AGREES WELL WITH ITS 00Z ENSEMBLE MEMBERS AND MATCHES WELL WITH ENSEMBLE MEAN. WE ALSO LOOKED AT 00Z NGM...AND IT ACTUALLY PRESENTS A DECENT SOLUTION. ITS SURFACE LOW IS SIMILAR TO GFS...BUT WE LIKE ITS 24HR QPF OF 0.50 TO 1.00" WHICH IS MUCH LOWER THAN NAM/GFS. OFTEN WE LIKE TO SEE NGM ON BOARD WITH SIGNIFICANT QPF BEFORE JUMPING ON A BIG EVENT...AND SINCE WE HAVE HAD DOUBTS AS TO EXCESSIVE QPF AMOUNTS SHOWN ON PAST RUNS OF NAM/GFS THIS LEADS MORE CREDENCE TO FACT THAT THOSE TWO MODELS ARE PROBABLY OVERDOING IT...ESPECIALLY GIVEN PROGRESSIVE NATURE OF THIS SYSTEM AS UPPER LOW DOES NOT CUTOFF UNTIL IT PASSES CAPE COD. SO IF WE ADJUST OUR TRACK TO JUST INSIDE 40/70 BENCHMARK...IT WOULD PLACE HEAVIEST PRECIPITATION ACROSS INTERIOR FROM NORTHERN CT INTO CENTRAL/INTERIOR NE MA AND SW NH. CROSS SECTIONS STILL SHOW TREMENDOUS MID LEVEL FRONTOGENESIS IN THIS REGION WITH EXCELLENT POTENTIAL FOR SLANTWISE CONVECTION/MESOSCALE BANDING. THIS IS ALSO ZONE OF MAXIMUM SNOW GROWTH. ONLY LIMITING FACTOR TO MAKING THIS A BLOCKBUSTER EVENT CONTINUES TO BE SPEED OF SYSTEM...SO ALTHOUGH IT'S GOING TO SNOW HARD FOR SEVERAL HOURS FROM MID MORNING INTO EARLY AFTERNOON WITH SNOWFALL RATES OF 2" PER HOUR...IT SHOULD NOT LAST LONG ENOUGH TO GIVE WIDESPREAD TOTALS OVER 10". WE'LL PROBABLY GET SOME THUNDER/LIGHTNING REPORTS WITH THIS AS WELL. CLOSER TO COAST...WE NEED TO DEAL WITH PRECIPITATION TYPE AS WE HAVE NO BLOCKING HIGH TO NORTH TO KEEP COLD AIR LOCKED IN AT LOW LEVELS. WINDS SHOULD EASILY BE ABLE TO TURN SE LATER THIS MORNING...ESPECIALLY SINCE MODELS SHOW 1000 MB AGEOSTROPHIC WINDS TURNING W...NOT A GOOD SIGN TO KEEP IT COLD. GFS CROSS SECTIONS MAY BE A LITTLE TOO WARM...INDICATING A CHANGE TO RAIN AS FAR INLAND AS I-495 IN EASTERN MA AND INTO NW RI. WE THINK IT IS MORE REALISTIC THAT THE TRANSITION ZONE (IE RAIN/SNOW MIX) WILL END UP NEAR I-95 BETWEEN BOSTON AND PROVIDENCE AND PROBABLY AS FAR N AS CAPE ANN. A COMPLETE CHANGE TO RAIN SEEMS MOST LIKELY WITHIN 5-10 MILES OF THE COAST FROM BOSTON TO PLYMOUTH...THEN ACROSS SE MA NEAR TAUNTON AND INTO PROVIDENCE. THAT BEING SAID...WE WILL NUDGE STORM TOTALS DOWN SLIGHTLY IN THESE LOCATIONS. WE CURRENTLY HAVE SE MIDDLESEX AND W NORFOLK COUNTIES IN A LOW-END WINTER STORM WARNING AND THAT STILL SEEMS REASONABLE...AS WE THINK PLACES ALONG ROUTE 128 FROM WOBURN AND BELMONT TO NEWTON AND DEDHAM WILL SEE THE 4-5" AMOUNTS AND LOCATIONS FARTHER INLAND SUCH AS LEXINGTON AND ESPECIALLY MEDWAY AND BELLINGHAM WILL SEE THE 6-8" TOTALS. IN THOSE ZONES WHERE WE HAVE A WINTER WEATHER ADVISORY...WE WILL GENERALLY HAVE 2-4" TOTALS. ONE EXCEPTION TO THIS IS IN COASTAL ESSEX COUNTY MA (ZONE 7)...WHERE WE EXPECT A WIDE RANGE IN TOTALS... FROM 2" ON COASTLINE TO AS MUCH AS 7-8" NEAR NH BORDER. BUT AVERAGE IS LOW ENOUGH TO KEEP AN ADVISORY GOING THERE. HEAVIEST SNOW SHOULD SHIFT INTO MERRIMACK VALLEY EARLY THIS AFTERNOON WHILE SNOWFALL RATES DECREASE BACK ACROSS CT VALLEY. STRONGEST LIFT IS HEADING QUICKLY FOR COAST BY MID AFTERNOON...SO WE THINK MANY LOCATIONS WILL SEE IMPROVING CONDITIONS BY 3 OR 4 PM EXCEPT FOR CAPE COD AND ISLANDS. MAIN CONCERN THEN BECOMES WIND. SURFACE LOW DEEPENING RAPIDLY OFF CAPE COD WILL CAUSE A RAPID INCREASE IN WINDS THROUGHOUT ALL OF REGION...BUT ESPECIALLY NEAR COAST. IF WE TAKE GFS SOUNDINGS FOR HYANNIS AND NANTUCKET AT FACE VALUE IT SHOWS A STRONG POTENTIAL OF 50-60KT GUSTS AS THIS DEEPENING OCCURS LATE THIS AFTERNOON AND EVENING. WE THINK THIS MAY BE A LITTLE HIGH...BUT WE HAVE ENOUGH CONFIDENCE TO ISSUE HIGH WIND WARNINGS AT THIS TIME. WIND ADVISORY WILL BE KEPT IN PLACE FOR S COAST...EVEN THOUGH CONFIDENCE ON 40KT GUSTS THERE IS LESS. ADVISORIES MAY ALSO NEED TO BE ISSUED FOR E MA COASTLINE BUT RIGHT NOW WE THINK WE WILL FALL SHORT OF CRITERIA THERE. CLEARING SHOULD WORK IN RAPIDLY THIS EVENING AS CROSS SECTIONS SHOW RAPID DRYING AND STRONG SUBSIDENCE...BUT WINDS WILL ONLY DIMINISH GRADUALLY UNTIL SYSTEM PULLS FARTHER OFFSHORE. LONG TERM (SATURDAY THROUGH THURSDAY)... OVERALL COLD AIR REMAINS IN PLACE OVER REGION THROUGH AT LEAST THURSDAY. WEAK RIDGE BUILDS OVER REGION SATURDAY IN WAKE OF DEPARTING STORM. SATURDAY NIGHT HEIGHTS BEGIN TO FALL AND WINDS BACK AS CYCLONIC FLOW BEGINS TO TAKE OVER. SHORTWAVES MOVE OVERHEAD THROUGH MONDAY WHILE AT THE SURFACE A DISORGANIZED LOW PRESSURE AREA MOVES ACROSS SOUTHERN QUEBEC TOWARD THE CANADIAN MARITIMES. COLD AIR ADVECTION ACROSS REGION COULD YIELD SHOWERS OVER OUTER WATERS CLIPPING CAPE AND ISLANDS. SURFACE HIGH PRESSURE BUILDS SOUTHEAST FROM CENTRAL CANADA...AND RESULTING N TO NW WINDS OVER CAPE COULD YIELD OCEAN EFFECT SNOW SHOWERS TUESDAY AND WEDNESDAY. RIDGING THROUGH THE COLUMN BUILDS OVER NEW ENGLAND THURSDAY...THEN REGION AWAITS NEXT POTENTIAL NOREASTER FOR FRIDAY. AVIATION... VFR FOR THE MOMENT...EXCEPT FOR MVFR CEILINGS NEAR NANTUCKET WHICH WILL SPREAD ONTO S COAST EARLY THIS MORNING. CONDITIONS WILL DETERIORATE RAPIDLY THIS MORNING TO IFR AS SNOW ARRIVES (THEN TO LIFR WITHIN 2 HOURS OF THAT)...CURRENTLY TIMED INTO CT VALLEY TOWARD SUNRISE AND BEFORE MID MORNING ALONG E MA COAST. CONDITIONS WILL LIFT TO MVFR THIS AFTERNOON AS HEAVIER SNOW SHIFTS OFFSHORE...THEN WE EXPECT RAPID IMPROVEMENT TO VFR BY EARLY THIS EVENING AS LOW PULLS OFF THE COAST. MARINE... WE WILL EXPAND STORM WARNINGS THIS AFTERNOON TO INCLUDE CAPE COD BAY AND NANTUCKET SOUND...AND MAINTAIN GALE WARNINGS ELSEWHERE AS WINDS INCREASE RAPIDLY BEHIND DEPARTING LOW. THERE IS STILL SOME QUESTION AS TO HOW FAST THE LOW WILL DEEPEN...IMPACTING WIND GUST POTENTIAL... BUT IT IS MORE LIKELY IT WILL OCCUR CLOSE ENOUGH TO CAPE COD RATHER THAN FARTHER OFFSHORE. WINDS AND SEAS SLOWLY DIMINISH OVERNIGHT AS SYSTEM PULLS FARTHER AWAY. FOLLOWED WNA WAVE GUIDANCE...HOWEVER GIVEN PREVAILING WEST TO SOUTHWEST WINDS SATURDAY AND SUNDAY...INCREASED SEAS IN BUZZARDS BAY. SMALL CRAFT ADVISORY CONDITIONS EXPECTED OVER THE WEEKEND FOR OUTER WATERS AND ALONG SOUTH COAST...ALL DUE TO WIND GUSTS TO 30 KTS AND ROUGH SEAS. WINDS AND SEAS SUBSIDE MONDAY AND TUESDAY. CLIMATE... FYI...RECORD DAILY SNOWFALL TOTALS FOR TODAY ARE AS FOLLOWS... KBOS... 4.6 INCHES IN 1978 KPVD... 3.0 INCHES IN 1995 KORH... 8.0 INCHES IN 1903 KBDL... 4.2 INCHES IN 1995 .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAVY SNOW WARNING FOR CTZ002>004 UNTIL 4 PM FRIDAY. MA...HEAVY SNOW WARNING FOR MAZ002>004-008>012 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR MAZ005-006-013-014-026 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR MAZ007-015-016-019>021 UNTIL 1 AM SATURDAY. ...WINTER WEATHER ADVISORY FOR MAZ007-015>019 UNTIL 5 PM FRIDAY. ...HIGH WIND WARNING FOR MAZ022>024 UNTIL 1 AM SATURDAY. NH...HEAVY SNOW WARNING FOR NHZ011 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR NHZ012-015 UNTIL 5 PM FRIDAY. RI...HEAVY SNOW WARNING FOR RIZ001 UNTIL 4 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR RIZ002>005 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR RIZ006>008 UNTIL 1 AM SATURDAY. MARINE...GALE WARNING FOR ANZ230-233>237 UNTIL 1 AM SATURDAY. ...STORM WARNING FOR ANZ231-232-250-254-255 UNTIL 1 AM SATURDAY. $$ SHORT TERM...NOCERA/EVT/NMB ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 347 PM EST FRI DEC 9 2005 ...BOMOGENESIS OCCURRING E OF CAPE COD ALNG WITH THUNDER SNOW IN BLOSSOMING COMMA HEAD MA COAST EASTWARD... M1...347 PM. GUSTS 69-72 KTS BUZ BAY TO 44029...CAPE WIND TOWER REPORTED (UNOFFICIAL) WEST WIND 64KTG81KT AT 3PM. WIND INSTRUMENT 20M ELEVATED...ABV THE NORMAL 10M OFFICIAL. SITING LIKENS TO A CMAN ELEVATED OB. WE HAVE LITTLE DOUBT 55 TO 70 KT NEAR SFC WINDS ALREADY OBSERVED. HEARING MOORINGS SEPARATING. DANGEROUS CONDS QUITTING ABRUPTLY NEXT 3 HRS. BRIEF BLIZ CONDS E MA COAST WILL END HEARD OF MINOR COASTAL FLOODING BUZ BAY EARLIER. REMAINDER BLO 158 PM. .SHORT TERM (REST OF TONIGHT)... WILD WINTER WEATHER HERE IN SNE...WITH SFC LOW UNDERGOING BOMOGENESIS IN RI SND AT 130 PM. SFC LOW WL MV QUICKLY E WITH LATEST ANALYSIS INDICATING 17 MB PRES DROP IN PAST 3 HRS CENTERED OVR ACK SND! SIGNIFICANT WND SHIFT BEHIND THIS LOW WITH WNDS GUSTING TO 55 MPH ACRS ERN LI AND INTO CSTL RI. IN ADDITION BUOY S OF LI GUSTING TO 58 KTS! THUS...HV EXPANDED WND ADV EWD INTO EAST COASTAL MA...INCLUDING BOSTON...CAPE ANN AND PYM COUNTY. STGST WNDS RI CST...INCLUDING BID AND EWD ACRS S.CST OF MA. IN ADDITION...VIGOROUS COMMA HEAD DEVELOPING OVR ERN CT/RI AND ERN MA IN RESPONSE TO SIGNIFICANT HEIGHT FALLS WITH UPPER LOW. GOOD CSI BANDING HAS MATERIALIZED WITH SVRL RPTS OF THUNDER SNOW ACRS THIS AREA. THIS CONVECTIVE BAND WL YIELD A QUICK 3-5 INCHES OF SNFL IN NE CT/NW RI AND E OF ORH IN MA...INCLUDING HILLSBORO CNTY. FARTHER SE INTO I95 CORRIDOR...MIXED PRECIP WL CHANGE TO SN WITH AN ADDITIONAL 2-4 INCHES OF ACCUMULATIONS BEFORE BACK EDGE OF PRECIP MVS OFSHR. STRONG WINDS WILL COMBINE WITH A CHANGEOVER OF SN TO YIELD NEAR WHITE OUT CONDITIONS FROM NOW (2 PM) TIL 4-5 PM IN THE PVD-BOS CORRIDOR AND LKLY TIL 6-7PM SE OF I95. WOW...WHAT A STORM! NOCERA .PREVIOUS DISCUSSION... (ISSUED 1100 AM EST FRI DEC 9 2005) ..MESOSCALE CONVECTIVE BAND OF SNOW DEVELOPING IN LOWER CT VALLEY TO SOUTHERN NH... MESO/NEAR TERM UPDATE... 15Z MESOANALYSIS INDICATES A COASTAL FRONT EXTENDING FROM ISLIP NY NORTHEAST ALONG LONG ISLAND...NEAR COASTAL RI...NORTHEAST TO NEW BEDFORD...NORTH TO BEVERLY. ALSO...A SURFACE TROF IS FORMING FROM THE LOW CENTER SOUTH OF ISLIP...NORTHWARD PAST NORTH ADAMS MA. 40 KM NAM SHOWS STRONG FRONTOGENESIS ALONG THESE 2 FEATURES FROM 15Z TO 18Z...AS THE LOW MOVES EAST. KALY RADAR SHOWING A DEVELOPING BAND OF HEAVY SNOW WITH 30 TO EVEN 40 DBZ REFLECTIVITY...MESOSCALE CONVECTIVE BAND....UNDER SURFACE TROF AND WHERE SECONDARY BAND OF STRONG FRONTOGENESIS WAS INDICATED. THUNDERSNOW REPORTED IN CHICOPEE AT 1050 AM...1/4SM S+ AT HFD...BAF...CEF AND AQW. KEENE NH REPORTS 10 INCHES OF SNOWFALL SO FAR. AT THIS TIME...THIS HEAVY SNOW BAND IS EXPECTED TO MOVE GRADUALLY EASTWARD ACROSS MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE THROUGH EARLY THIS AFTERNOON. SNOWFALL RATES OF 1 TO 2 INCHES AN HOUR...AND ISOLATED 3 INCH PER HOUR SNOWFALL...ARE EXPECTED UNDER 30 TO 40 DBZ REFLECTIVITY. FOR COASTAL SOUTHERN NEW ENGLAND...KBOX RADAR PICKING UP ON BRIGHT BANDING...SOME MELTING OCCURRING ALOFT WITH REPORTS OF SLEET...RAIN ..AND FREEZING RAIN IN SOUTH COASTAL MA AND COASTAL RI. MIX TO RAIN LINE WAS ALONG A KINGSTON...PVD...PYM TO NEAR BVY LINE. COASTAL FRONT MAY PULL INLAND SOME OVER NEXT FEW HOURS. MIX SUPPORTS KEEPING WINTER WEATHER ADVISORIES AS THEY ARE AT THIS TIME. MARINE... MSAS INDICATING RAPID SURFACE PRESSURE FALLS OF UP TO 9 MB IN 3 HOURS...AND TIGHTENING GRADIENT. PLAN TO MENTION GUSTS TO 55 KT IN OUTER COASTAL WATERS...WHERE STORM WARNINGS ARE ALREADY IN EFFECT. NBELK PREVIOUS DISCUSSION... (ISSUED 920 AM EST FRI DEC 9 2005)... MESO/SHORT TERM UPDATE (REST OF TODAY)... COMPLEX WINTER SCENARIO UNFOLDING THIS AM...ESPECIALLY CAPE COD CANAL TO I95 CORRIDOR WHERE CSTL FNT BEGINNING TO DVLP. PARENT SFC LOW OVR LK ONTARIO BEGINNING TO WEAKEN/FILL...WHILE CSTL LOW JUST E OF NJ BEGINS TO INTENSIFY WITH SIGNIFICANT PRES FALLS CENTERED JUST S. OF MONTAUK ON THE ORDER OF -8 MBS DURING THE PAST 3 HRS. THESE PRES FALLS WL GRADUALLY BACK SFC WNDS TO N-NE OVR THE AREA AS THE MORNING PROGRESSES...WHICH WL RETARD THE N MVMNT OF THE CSTL FNT AND MIXED PRECIP LINE. THIS IS APPARENT IN THE 14Z SFC OBS...WITH SE WND AT BID AND NE WND AT GON AND WST. THE RESULT HERE IS FOR SUBFREEZING SFC LYR TO BE DELAYED MVG NWD FM CAPE COD CANAL TO I95. FURTHER COMPLICATING THIS AREA...IS THAT SUFFICIENT WARMING/MELTING IS OCCURRING ABV THE SFC LYR (PER STG SE INFLOW ON KBOX VAD WND PROFILE) ACRS THIS AREA FOR SN TO CHANGE TO SLEET AND OR FREEZING RN...AS WST AND GON RPTG -FZRA ANS SVRL SPOTTER RPTG SLEET. ALSO...KBOX COMPOSITE RADAR IMAGERY PICKING UP ON THIS WELL...WITH HIGH REFLECTIVITY OVR NARRAGANSETT BAY INDICATING SLEET. SO CURRENT FCST OF RN-SN LINE TRAVERSING NWWD INTO I95 CORRIDOR AND PSSBLY AS FAR NW AS I495 LKS GD. HWR...GIVEN LATEST TRENDS/CSTL FNT DVLPMNT AND STG PRES FALLS...SUBFREEZING SFC LYR WL BE DELAYED MVG NWD AND WL YIELD MORE OF A WINTRY MIX OF FZRA AND SLEET FM CAPE COD CANAL INTO I95. THUS...WL UPDATED WX GRIDS TO REFLECT MIXED PTYPE TRANSITION...RATHER THAN A CLEAN PTYPE CHANGE FM SN TO RN. INLAND...ESPECIALLY N OF THE MASS TURNPIKE AND NW OF I495 IT IS FAIRLY STRAIGHT FORWARD...WITH PTYPE REMAINING ALL SNOW. NO CHANGES TO SNOW ACCUMULATIONS AT THE MOMENT. ALTH...WL HV TO WATCH TRENDS OF CSTL FNT ALONG WITH STG PRES FALLS OFF THE S.CST. IF CSTL FNT REMAINS FARTHER S...BLYR WRMG MAY BE TOO MARGINAL FOR A CHANGEOVER AND STG UPWARD VERTICAL MOTION MAY BE ABLE TO COMPENSATE VIA DYNAMICAL AND DIABATIC COOLING PROCESSES. THEREFORE...COULD HAVE LESS MIXING IN FROM I495 TO I95 YIELDING HIER SN TOTALS. WL JUST HV TO MONITOR TRENDS AND AWAIT 12Z MDL GUID. NOCERA PREVIOUS DISCUSSION... (ISSUED 500 AM EST FRI DEC 9 2005) SHORT TERM (TODAY)... MESO DISCUSSION AND 06Z MODEL UPDATE... SNOW HAS MADE IT INTO NYC AND JUST STARTED IN HARTFORD AS WELL AS BERKSHIRES AND MONADNOCKS. KBOX RADAR SHOWS AN INITIAL BAND OF SNOW FROM MANCHESTER TO CAPE ANN AND OFFSHORE WHICH FOR MOST PART IS ALOFT...BUT IT IS GIVING A QUICK SHOT OF SNOW TO SOUTHERN NH. YOU CAN SEE THE DRY AIR AT LOWER LEVELS VERY WELL ON KBOX RADAR TOO... COVERING MUCH OF EASTERN MA AND RI. THIS WILL SLOWLY MOISTEN DURING NEXT COUPLE OF HOURS AND WE EXPECT SNOW TO REACH WORCESTER AND PROVIDENCE BY 7 AM AND BOSTON AROUND 8 AM OR SO. MODELS ARE TRENDING CLOSER WITH EACH RUN. 06Z NAM IS NOW A BIT FARTHER S WITH ITS LOW TRACK...NOW FROM MONTAUK POINT TO CAPE COD BAY WITH GFS HOLDING FIRM ON ITS TRACK S OF NANTUCKET. OTHER MESOSCALE MODELS INCLUDING 06Z RUC AND 06Z 10KM BOX ETA PREFER A TRACK CLOSER TO NAM...BUT THIS JUST SEEMS A BIT TOO FAR N TO US. ONE THING WE NOTICED IS NAM IS STILL A BIT SLOWER...AND BRINGS BEST LIFT INTO SOUTHERN NEW ENGLAND FROM MID MORNING INTO MID AFTERNOON...SO WE ARE STILL ON TARGET FOR 1-2"/HR SNOWFALL RATES...ESPECIALLY FOR HARTFORD TO WORCESTER AND LAWRENCE CORRIDOR WHERE SNOWFLAKE PRODUCTION WILL BE MAXIMIZED. WE HAVE SOME CONCERN THAT THIS STRONG LIFT MAY BE ABLE TO COMPENSATE ENOUGH FOR MARGINALLY WARM LOW LEVEL TEMPERATURES IN BOSTON AREA. IT STILL APPEARS WARM ENOUGH FOR A CHANGE TO RAIN IN PROVIDENCE AND SE MA. BOSTON MAY VERY WELL END UP SEEING MORE OF A MIX AS OPPOSED TO A CHANGE TO RAIN SHOULD NAM VERIFY...BUT A PROLONGED SE WIND USUALLY KILLS THE SNOWFLAKES IN BOSTON. ONE THING THAT HAS BEEN IMPRESSIVE SO FAR IS WHAT'S BEEN GOING ON UPSTREAM ACROSS MID ATLANTIC...ESPECIALLY FROM WASHINGTON DC INTO PA WHERE THERE HAVE BEEN MANY REPORTS OF 1-2"/HR SNOWFALL RATES AND EVEN THUNDER! THIS SHOULD ALL COME OUR WAY LATER THIS MORNING AND EARLY THIS AFTERNOON. JWD PREVIOUS DISCUSSION... (ISSUED 335 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH TONIGHT)... WE ARE KEEPING ALL WARNINGS AND ADVISORIES IN PLACE FOR SNOW TODAY... BUT WILL TRIM AMOUNTS DOWN SLIGHTLY NEAR I-95 CORRIDOR WHICH SHOULD SERVE AS OUR TRANSITION ZONE. TOTALS ACROSS INTERIOR LOOK GOOD. WE WILL ALSO UPGRADE THE HIGH WIND WATCH FOR CAPE COD AND THE ISLANDS TO A HIGH WIND WARNING. LEADING EDGE OF SNOW IS CURRENTLY WORKING THROUGH CENTRAL NY AND EASTERN PA...NOTE HOW QUICKLY VISIBILITIES DROP TO 1/2SM OR LESS AS SNOW BEGINS! ALTHOUGH WE HAVE PLENTY OF LOW LEVEL DRY AIR TO OVERCOME...IT WON'T TAKE LONG TO SATURATE THE COLUMN WITH SUCH A POTENT SYSTEM ON OUR DOORSTEP. WE EXPECT SNOW TO BEGIN IN CT VALLEY AROUND SUNRISE (PROBABLY 6 AM) AND QUICKLY HEAD TO E MA COAST DURING MORNING RUSH HOUR (8-9 AM)...PLUS/MINUS AN HOUR OR TWO. 00Z NAM STILL FARTHEST N OF MODELS THIS MORNING...BUT 00Z GFS CONTINUES ITS TREND OF EDGING FARTHER N WITH EACH RUN...NOW TAKING SECONDARY LOW JUST SE OF NANTUCKET. IT AGREES WELL WITH ITS 00Z ENSEMBLE MEMBERS AND MATCHES WELL WITH ENSEMBLE MEAN. WE ALSO LOOKED AT 00Z NGM...AND IT ACTUALLY PRESENTS A DECENT SOLUTION. ITS SURFACE LOW IS SIMILAR TO GFS...BUT WE LIKE ITS 24HR QPF OF 0.50 TO 1.00" WHICH IS MUCH LOWER THAN NAM/GFS. OFTEN WE LIKE TO SEE NGM ON BOARD WITH SIGNIFICANT QPF BEFORE JUMPING ON A BIG EVENT...AND SINCE WE HAVE HAD DOUBTS AS TO EXCESSIVE QPF AMOUNTS SHOWN ON PAST RUNS OF NAM/GFS THIS LEADS MORE CREDENCE TO FACT THAT THOSE TWO MODELS ARE PROBABLY OVERDOING IT...ESPECIALLY GIVEN PROGRESSIVE NATURE OF THIS SYSTEM AS UPPER LOW DOES NOT CUTOFF UNTIL IT PASSES CAPE COD. SO IF WE ADJUST OUR TRACK TO JUST INSIDE 40/70 BENCHMARK...IT WOULD PLACE HEAVIEST PRECIPITATION ACROSS INTERIOR FROM NORTHERN CT INTO CENTRAL/INTERIOR NE MA AND SW NH. CROSS SECTIONS STILL SHOW TREMENDOUS MID LEVEL FRONTOGENESIS IN THIS REGION WITH EXCELLENT POTENTIAL FOR SLANTWISE CONVECTION/MESOSCALE BANDING. THIS IS ALSO ZONE OF MAXIMUM SNOW GROWTH. ONLY LIMITING FACTOR TO MAKING THIS A BLOCKBUSTER EVENT CONTINUES TO BE SPEED OF SYSTEM...SO ALTHOUGH IT'S GOING TO SNOW HARD FOR SEVERAL HOURS FROM MID MORNING INTO EARLY AFTERNOON WITH SNOWFALL RATES OF 2" PER HOUR...IT SHOULD NOT LAST LONG ENOUGH TO GIVE WIDESPREAD TOTALS OVER 10". WE'LL PROBABLY GET SOME THUNDER/LIGHTNING REPORTS WITH THIS AS WELL. CLOSER TO COAST...WE NEED TO DEAL WITH PRECIPITATION TYPE AS WE HAVE NO BLOCKING HIGH TO NORTH TO KEEP COLD AIR LOCKED IN AT LOW LEVELS. WINDS SHOULD EASILY BE ABLE TO TURN SE LATER THIS MORNING...ESPECIALLY SINCE MODELS SHOW 1000 MB AGEOSTROPHIC WINDS TURNING W...NOT A GOOD SIGN TO KEEP IT COLD. GFS CROSS SECTIONS MAY BE A LITTLE TOO WARM...INDICATING A CHANGE TO RAIN AS FAR INLAND AS I-495 IN EASTERN MA AND INTO NW RI. WE THINK IT IS MORE REALISTIC THAT THE TRANSITION ZONE (IE RAIN/SNOW MIX) WILL END UP NEAR I-95 BETWEEN BOSTON AND PROVIDENCE AND PROBABLY AS FAR N AS CAPE ANN. A COMPLETE CHANGE TO RAIN SEEMS MOST LIKELY WITHIN 5-10 MILES OF THE COAST FROM BOSTON TO PLYMOUTH...THEN ACROSS SE MA NEAR TAUNTON AND INTO PROVIDENCE. THAT BEING SAID...WE WILL NUDGE STORM TOTALS DOWN SLIGHTLY IN THESE LOCATIONS. WE CURRENTLY HAVE SE MIDDLESEX AND W NORFOLK COUNTIES IN A LOW-END WINTER STORM WARNING AND THAT STILL SEEMS REASONABLE...AS WE THINK PLACES ALONG ROUTE 128 FROM WOBURN AND BELMONT TO NEWTON AND DEDHAM WILL SEE THE 4-5" AMOUNTS AND LOCATIONS FARTHER INLAND SUCH AS LEXINGTON AND ESPECIALLY MEDWAY AND BELLINGHAM WILL SEE THE 6-8" TOTALS. IN THOSE ZONES WHERE WE HAVE A WINTER WEATHER ADVISORY...WE WILL GENERALLY HAVE 2-4" TOTALS. ONE EXCEPTION TO THIS IS IN COASTAL ESSEX COUNTY MA (ZONE 7)...WHERE WE EXPECT A WIDE RANGE IN TOTALS... FROM 2" ON COASTLINE TO AS MUCH AS 7-8" NEAR NH BORDER. BUT AVERAGE IS LOW ENOUGH TO KEEP AN ADVISORY GOING THERE. HEAVIEST SNOW SHOULD SHIFT INTO MERRIMACK VALLEY EARLY THIS AFTERNOON WHILE SNOWFALL RATES DECREASE BACK ACROSS CT VALLEY. STRONGEST LIFT IS HEADING QUICKLY FOR COAST BY MID AFTERNOON...SO WE THINK MANY LOCATIONS WILL SEE IMPROVING CONDITIONS BY 3 OR 4 PM EXCEPT FOR CAPE COD AND ISLANDS. MAIN CONCERN THEN BECOMES WIND. SURFACE LOW DEEPENING RAPIDLY OFF CAPE COD WILL CAUSE A RAPID INCREASE IN WINDS THROUGHOUT ALL OF REGION...BUT ESPECIALLY NEAR COAST. IF WE TAKE GFS SOUNDINGS FOR HYANNIS AND NANTUCKET AT FACE VALUE IT SHOWS A STRONG POTENTIAL OF 50-60KT GUSTS AS THIS DEEPENING OCCURS LATE THIS AFTERNOON AND EVENING. WE THINK THIS MAY BE A LITTLE HIGH...BUT WE HAVE ENOUGH CONFIDENCE TO ISSUE HIGH WIND WARNINGS AT THIS TIME. WIND ADVISORY WILL BE KEPT IN PLACE FOR S COAST...EVEN THOUGH CONFIDENCE ON 40KT GUSTS THERE IS LESS. ADVISORIES MAY ALSO NEED TO BE ISSUED FOR E MA COASTLINE BUT RIGHT NOW WE THINK WE WILL FALL SHORT OF CRITERIA THERE. CLEARING SHOULD WORK IN RAPIDLY THIS EVENING AS CROSS SECTIONS SHOW RAPID DRYING AND STRONG SUBSIDENCE...BUT WINDS WILL ONLY DIMINISH GRADUALLY UNTIL SYSTEM PULLS FARTHER OFFSHORE. LONG TERM (SATURDAY THROUGH THURSDAY)... OVERALL COLD AIR REMAINS IN PLACE OVER REGION THROUGH AT LEAST THURSDAY. WEAK RIDGE BUILDS OVER REGION SATURDAY IN WAKE OF DEPARTING STORM. SATURDAY NIGHT HEIGHTS BEGIN TO FALL AND WINDS BACK AS CYCLONIC FLOW BEGINS TO TAKE OVER. SHORTWAVES MOVE OVERHEAD THROUGH MONDAY WHILE AT THE SURFACE A DISORGANIZED LOW PRESSURE AREA MOVES ACROSS SOUTHERN QUEBEC TOWARD THE CANADIAN MARITIMES. COLD AIR ADVECTION ACROSS REGION COULD YIELD SHOWERS OVER OUTER WATERS CLIPPING CAPE AND ISLANDS. SURFACE HIGH PRESSURE BUILDS SOUTHEAST FROM CENTRAL CANADA...AND RESULTING N TO NW WINDS OVER CAPE COULD YIELD OCEAN EFFECT SNOW SHOWERS TUESDAY AND WEDNESDAY. RIDGING THROUGH THE COLUMN BUILDS OVER NEW ENGLAND THURSDAY...THEN REGION AWAITS NEXT POTENTIAL NOREASTER FOR FRIDAY. AVIATION... VFR FOR THE MOMENT...EXCEPT FOR MVFR CEILINGS NEAR NANTUCKET WHICH WILL SPREAD ONTO S COAST EARLY THIS MORNING. CONDITIONS WILL DETERIORATE RAPIDLY THIS MORNING TO IFR AS SNOW ARRIVES (THEN TO LIFR WITHIN 2 HOURS OF THAT)...CURRENTLY TIMED INTO CT VALLEY TOWARD SUNRISE AND BEFORE MID MORNING ALONG E MA COAST. CONDITIONS WILL LIFT TO MVFR THIS AFTERNOON AS HEAVIER SNOW SHIFTS OFFSHORE...THEN WE EXPECT RAPID IMPROVEMENT TO VFR BY EARLY THIS EVENING AS LOW PULLS OFF THE COAST. MARINE... WE WILL EXPAND STORM WARNINGS THIS AFTERNOON TO INCLUDE CAPE COD BAY AND NANTUCKET SOUND...AND MAINTAIN GALE WARNINGS ELSEWHERE AS WINDS INCREASE RAPIDLY BEHIND DEPARTING LOW. THERE IS STILL SOME QUESTION AS TO HOW FAST THE LOW WILL DEEPEN...IMPACTING WIND GUST POTENTIAL... BUT IT IS MORE LIKELY IT WILL OCCUR CLOSE ENOUGH TO CAPE COD RATHER THAN FARTHER OFFSHORE. WINDS AND SEAS SLOWLY DIMINISH OVERNIGHT AS SYSTEM PULLS FARTHER AWAY. FOLLOWED WNA WAVE GUIDANCE...HOWEVER GIVEN PREVAILING WEST TO SOUTHWEST WINDS SATURDAY AND SUNDAY...INCREASED SEAS IN BUZZARDS BAY. SMALL CRAFT ADVISORY CONDITIONS EXPECTED OVER THE WEEKEND FOR OUTER WATERS AND ALONG SOUTH COAST...ALL DUE TO WIND GUSTS TO 30 KTS AND ROUGH SEAS. WINDS AND SEAS SUBSIDE MONDAY AND TUESDAY. CLIMATE... FYI...RECORD DAILY SNOWFALL TOTALS FOR TODAY ARE AS FOLLOWS... KBOS... 4.6 INCHES IN 1978 KPVD... 3.0 INCHES IN 1995 KORH... 8.0 INCHES IN 1903 KBDL... 4.2 INCHES IN 1995 .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAVY SNOW WARNING FOR CTZ002>004 UNTIL 4 PM FRIDAY. MA...HEAVY SNOW WARNING FOR MAZ002>004-008>012 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR MAZ005-006-013-014-026 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR MAZ007-015-016-019>021 UNTIL 1 AM SATURDAY. ...WINTER WEATHER ADVISORY FOR MAZ007-015>019 UNTIL 5 PM FRIDAY. ...HIGH WIND WARNING FOR MAZ022>024 UNTIL 1 AM SATURDAY. NH...HEAVY SNOW WARNING FOR NHZ011 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR NHZ012-015 UNTIL 5 PM FRIDAY. RI...HEAVY SNOW WARNING FOR RIZ001 UNTIL 4 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR RIZ002>005 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR RIZ006>008 UNTIL 1 AM SATURDAY. MARINE...GALE WARNING FOR ANZ230-233>237 UNTIL 1 AM SATURDAY. ...STORM WARNING FOR ANZ231-232-250-254-255 UNTIL 1 AM SATURDAY. $$ SHORT TERM...NOCERA/EVT/NMB ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 158 PM EST FRI DEC 9 2005 ...BOMOGENESIS OCCURRING IN RI SND ALNG WITH THUNDER SNOW IN BLOSSOMING COMMA HEAD... .SHORT TERM (REST OF TONIGHT)... WILD WINTER WEATHER HERE IN SNE...WITH SFC LOW UNDERGOING BOMOGENESIS IN RI SND AT 130 PM. SFC LOW WL MV QUICKLY E WITH LATEST ANALYSIS INDICATING 17 MB PRES DROP IN PAST 3 HRS CENTERED OVR ACK SND! SIGNIFICANT WND SHIFT BEHIND THIS LOW WITH WNDS GUSTING TO 55 MPH ACRS ERN LI AND INTO CSTL RI. IN ADDITION BUOY S OF LI GUSTING TO 58 KTS! THUS...HV EXPANDED WND ADV EWD INTO EAST COASTAL MA...INCLUDING BOSTON...CAPE ANN AND PYM COUNTY. STGST WNDS RI CST...INCLUDING BID AND EWD ACRS S.CST OF MA. IN ADDITION...VIGOROUS COMMA HEAD DEVELOPING OVR ERN CT/RI AND ERN MA IN RESPONSE TO SIGNIFICANT HEIGHT FALLS WITH UPPER LOW. GOOD CSI BANDING HAS MATERIALIZED WITH SVRL RPTS OF THUNDER SNOW ACRS THIS AREA. THIS CONVECTIVE BAND WL YIELD A QUICK 3-5 INCHES OF SNFL IN NE CT/NW RI AND E OF ORH IN MA...INCLUDING HILLSBORO CNTY. FARTHER SE INTO I95 CORRIDOR...MIXED PRECIP WL CHANGE TO SN WITH AN ADDITIONAL 2-4 INCHES OF ACCUMULATIONS BEFORE BACK EDGE OF PRECIP MVS OFSHR. STRONG WINDS WILL COMBINE WITH A CHANGEOVER OF SN TO YIELD NEAR WHITE OUT CONDITIONS FROM NOW (2 PM) TIL 4-5 PM IN THE PVD-BOS CORRIDOR AND LKLY TIL 6-7PM SE OF I95. WOW...WHAT A STORM! NOCERA .PREVIOUS DISCUSSION... (ISSUED 1100 AM EST FRI DEC 9 2005) ..MESOSCALE CONVECTIVE BAND OF SNOW DEVELOPING IN LOWER CT VALLEY TO SOUTHERN NH... MESO/NEAR TERM UPDATE... 15Z MESOANALYSIS INDICATES A COASTAL FRONT EXTENDING FROM ISLIP NY NORTHEAST ALONG LONG ISLAND...NEAR COASTAL RI...NORTHEAST TO NEW BEDFORD...NORTH TO BEVERLY. ALSO...A SURFACE TROF IS FORMING FROM THE LOW CENTER SOUTH OF ISLIP...NORTHWARD PAST NORTH ADAMS MA. 40 KM NAM SHOWS STRONG FRONTOGENESIS ALONG THESE 2 FEATURES FROM 15Z TO 18Z...AS THE LOW MOVES EAST. KALY RADAR SHOWING A DEVELOPING BAND OF HEAVY SNOW WITH 30 TO EVEN 40 DBZ REFLECTIVITY...MESOSCALE CONVECTIVE BAND....UNDER SURFACE TROF AND WHERE SECONDARY BAND OF STRONG FRONTOGENESIS WAS INDICATED. THUNDERSNOW REPORTED IN CHICOPEE AT 1050 AM...1/4SM S+ AT HFD...BAF...CEF AND AQW. KEENE NH REPORTS 10 INCHES OF SNOWFALL SO FAR. AT THIS TIME...THIS HEAVY SNOW BAND IS EXPECTED TO MOVE GRADUALLY EASTWARD ACROSS MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE THROUGH EARLY THIS AFTERNOON. SNOWFALL RATES OF 1 TO 2 INCHES AN HOUR...AND ISOLATED 3 INCH PER HOUR SNOWFALL...ARE EXPECTED UNDER 30 TO 40 DBZ REFLECTIVITY. FOR COASTAL SOUTHERN NEW ENGLAND...KBOX RADAR PICKING UP ON BRIGHT BANDING...SOME MELTING OCCURRING ALOFT WITH REPORTS OF SLEET...RAIN ..AND FREEZING RAIN IN SOUTH COASTAL MA AND COASTAL RI. MIX TO RAIN LINE WAS ALONG A KINGSTON...PVD...PYM TO NEAR BVY LINE. COASTAL FRONT MAY PULL INLAND SOME OVER NEXT FEW HOURS. MIX SUPPORTS KEEPING WINTER WEATHER ADVISORIES AS THEY ARE AT THIS TIME. MARINE... MSAS INDICATING RAPID SURFACE PRESSURE FALLS OF UP TO 9 MB IN 3 HOURS...AND TIGHTENING GRADIENT. PLAN TO MENTION GUSTS TO 55 KT IN OUTER COASTAL WATERS...WHERE STORM WARNINGS ARE ALREADY IN EFFECT. NBELK PREVIOUS DISCUSSION... (ISSUED 920 AM EST FRI DEC 9 2005)... MESO/SHORT TERM UPDATE (REST OF TODAY)... COMPLEX WINTER SCENARIO UNFOLDING THIS AM...ESPECIALLY CAPE COD CANAL TO I95 CORRIDOR WHERE CSTL FNT BEGINNING TO DVLP. PARENT SFC LOW OVR LK ONTARIO BEGINNING TO WEAKEN/FILL...WHILE CSTL LOW JUST E OF NJ BEGINS TO INTENSIFY WITH SIGNIFICANT PRES FALLS CENTERED JUST S. OF MONTAUK ON THE ORDER OF -8 MBS DURING THE PAST 3 HRS. THESE PRES FALLS WL GRADUALLY BACK SFC WNDS TO N-NE OVR THE AREA AS THE MORNING PROGRESSES...WHICH WL RETARD THE N MVMNT OF THE CSTL FNT AND MIXED PRECIP LINE. THIS IS APPARENT IN THE 14Z SFC OBS...WITH SE WND AT BID AND NE WND AT GON AND WST. THE RESULT HERE IS FOR SUBFREEZING SFC LYR TO BE DELAYED MVG NWD FM CAPE COD CANAL TO I95. FURTHER COMPLICATING THIS AREA...IS THAT SUFFICIENT WARMING/MELTING IS OCCURRING ABV THE SFC LYR (PER STG SE INFLOW ON KBOX VAD WND PROFILE) ACRS THIS AREA FOR SN TO CHANGE TO SLEET AND OR FREEZING RN...AS WST AND GON RPTG -FZRA ANS SVRL SPOTTER RPTG SLEET. ALSO...KBOX COMPOSITE RADAR IMAGERY PICKING UP ON THIS WELL...WITH HIGH REFLECTIVITY OVR NARRAGANSETT BAY INDICATING SLEET. SO CURRENT FCST OF RN-SN LINE TRAVERSING NWWD INTO I95 CORRIDOR AND PSSBLY AS FAR NW AS I495 LKS GD. HWR...GIVEN LATEST TRENDS/CSTL FNT DVLPMNT AND STG PRES FALLS...SUBFREEZING SFC LYR WL BE DELAYED MVG NWD AND WL YIELD MORE OF A WINTRY MIX OF FZRA AND SLEET FM CAPE COD CANAL INTO I95. THUS...WL UPDATED WX GRIDS TO REFLECT MIXED PTYPE TRANSITION...RATHER THAN A CLEAN PTYPE CHANGE FM SN TO RN. INLAND...ESPECIALLY N OF THE MASS TURNPIKE AND NW OF I495 IT IS FAIRLY STRAIGHT FORWARD...WITH PTYPE REMAINING ALL SNOW. NO CHANGES TO SNOW ACCUMULATIONS AT THE MOMENT. ALTH...WL HV TO WATCH TRENDS OF CSTL FNT ALONG WITH STG PRES FALLS OFF THE S.CST. IF CSTL FNT REMAINS FARTHER S...BLYR WRMG MAY BE TOO MARGINAL FOR A CHANGEOVER AND STG UPWARD VERTICAL MOTION MAY BE ABLE TO COMPENSATE VIA DYNAMICAL AND DIABATIC COOLING PROCESSES. THEREFORE...COULD HAVE LESS MIXING IN FROM I495 TO I95 YIELDING HIER SN TOTALS. WL JUST HV TO MONITOR TRENDS AND AWAIT 12Z MDL GUID. NOCERA PREVIOUS DISCUSSION... (ISSUED 500 AM EST FRI DEC 9 2005) SHORT TERM (TODAY)... MESO DISCUSSION AND 06Z MODEL UPDATE... SNOW HAS MADE IT INTO NYC AND JUST STARTED IN HARTFORD AS WELL AS BERKSHIRES AND MONADNOCKS. KBOX RADAR SHOWS AN INITIAL BAND OF SNOW FROM MANCHESTER TO CAPE ANN AND OFFSHORE WHICH FOR MOST PART IS ALOFT...BUT IT IS GIVING A QUICK SHOT OF SNOW TO SOUTHERN NH. YOU CAN SEE THE DRY AIR AT LOWER LEVELS VERY WELL ON KBOX RADAR TOO... COVERING MUCH OF EASTERN MA AND RI. THIS WILL SLOWLY MOISTEN DURING NEXT COUPLE OF HOURS AND WE EXPECT SNOW TO REACH WORCESTER AND PROVIDENCE BY 7 AM AND BOSTON AROUND 8 AM OR SO. MODELS ARE TRENDING CLOSER WITH EACH RUN. 06Z NAM IS NOW A BIT FARTHER S WITH ITS LOW TRACK...NOW FROM MONTAUK POINT TO CAPE COD BAY WITH GFS HOLDING FIRM ON ITS TRACK S OF NANTUCKET. OTHER MESOSCALE MODELS INCLUDING 06Z RUC AND 06Z 10KM BOX ETA PREFER A TRACK CLOSER TO NAM...BUT THIS JUST SEEMS A BIT TOO FAR N TO US. ONE THING WE NOTICED IS NAM IS STILL A BIT SLOWER...AND BRINGS BEST LIFT INTO SOUTHERN NEW ENGLAND FROM MID MORNING INTO MID AFTERNOON...SO WE ARE STILL ON TARGET FOR 1-2"/HR SNOWFALL RATES...ESPECIALLY FOR HARTFORD TO WORCESTER AND LAWRENCE CORRIDOR WHERE SNOWFLAKE PRODUCTION WILL BE MAXIMIZED. WE HAVE SOME CONCERN THAT THIS STRONG LIFT MAY BE ABLE TO COMPENSATE ENOUGH FOR MARGINALLY WARM LOW LEVEL TEMPERATURES IN BOSTON AREA. IT STILL APPEARS WARM ENOUGH FOR A CHANGE TO RAIN IN PROVIDENCE AND SE MA. BOSTON MAY VERY WELL END UP SEEING MORE OF A MIX AS OPPOSED TO A CHANGE TO RAIN SHOULD NAM VERIFY...BUT A PROLONGED SE WIND USUALLY KILLS THE SNOWFLAKES IN BOSTON. ONE THING THAT HAS BEEN IMPRESSIVE SO FAR IS WHAT'S BEEN GOING ON UPSTREAM ACROSS MID ATLANTIC...ESPECIALLY FROM WASHINGTON DC INTO PA WHERE THERE HAVE BEEN MANY REPORTS OF 1-2"/HR SNOWFALL RATES AND EVEN THUNDER! THIS SHOULD ALL COME OUR WAY LATER THIS MORNING AND EARLY THIS AFTERNOON. JWD PREVIOUS DISCUSSION... (ISSUED 335 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH TONIGHT)... WE ARE KEEPING ALL WARNINGS AND ADVISORIES IN PLACE FOR SNOW TODAY... BUT WILL TRIM AMOUNTS DOWN SLIGHTLY NEAR I-95 CORRIDOR WHICH SHOULD SERVE AS OUR TRANSITION ZONE. TOTALS ACROSS INTERIOR LOOK GOOD. WE WILL ALSO UPGRADE THE HIGH WIND WATCH FOR CAPE COD AND THE ISLANDS TO A HIGH WIND WARNING. LEADING EDGE OF SNOW IS CURRENTLY WORKING THROUGH CENTRAL NY AND EASTERN PA...NOTE HOW QUICKLY VISIBILITIES DROP TO 1/2SM OR LESS AS SNOW BEGINS! ALTHOUGH WE HAVE PLENTY OF LOW LEVEL DRY AIR TO OVERCOME...IT WON'T TAKE LONG TO SATURATE THE COLUMN WITH SUCH A POTENT SYSTEM ON OUR DOORSTEP. WE EXPECT SNOW TO BEGIN IN CT VALLEY AROUND SUNRISE (PROBABLY 6 AM) AND QUICKLY HEAD TO E MA COAST DURING MORNING RUSH HOUR (8-9 AM)...PLUS/MINUS AN HOUR OR TWO. 00Z NAM STILL FARTHEST N OF MODELS THIS MORNING...BUT 00Z GFS CONTINUES ITS TREND OF EDGING FARTHER N WITH EACH RUN...NOW TAKING SECONDARY LOW JUST SE OF NANTUCKET. IT AGREES WELL WITH ITS 00Z ENSEMBLE MEMBERS AND MATCHES WELL WITH ENSEMBLE MEAN. WE ALSO LOOKED AT 00Z NGM...AND IT ACTUALLY PRESENTS A DECENT SOLUTION. ITS SURFACE LOW IS SIMILAR TO GFS...BUT WE LIKE ITS 24HR QPF OF 0.50 TO 1.00" WHICH IS MUCH LOWER THAN NAM/GFS. OFTEN WE LIKE TO SEE NGM ON BOARD WITH SIGNIFICANT QPF BEFORE JUMPING ON A BIG EVENT...AND SINCE WE HAVE HAD DOUBTS AS TO EXCESSIVE QPF AMOUNTS SHOWN ON PAST RUNS OF NAM/GFS THIS LEADS MORE CREDENCE TO FACT THAT THOSE TWO MODELS ARE PROBABLY OVERDOING IT...ESPECIALLY GIVEN PROGRESSIVE NATURE OF THIS SYSTEM AS UPPER LOW DOES NOT CUTOFF UNTIL IT PASSES CAPE COD. SO IF WE ADJUST OUR TRACK TO JUST INSIDE 40/70 BENCHMARK...IT WOULD PLACE HEAVIEST PRECIPITATION ACROSS INTERIOR FROM NORTHERN CT INTO CENTRAL/INTERIOR NE MA AND SW NH. CROSS SECTIONS STILL SHOW TREMENDOUS MID LEVEL FRONTOGENESIS IN THIS REGION WITH EXCELLENT POTENTIAL FOR SLANTWISE CONVECTION/MESOSCALE BANDING. THIS IS ALSO ZONE OF MAXIMUM SNOW GROWTH. ONLY LIMITING FACTOR TO MAKING THIS A BLOCKBUSTER EVENT CONTINUES TO BE SPEED OF SYSTEM...SO ALTHOUGH IT'S GOING TO SNOW HARD FOR SEVERAL HOURS FROM MID MORNING INTO EARLY AFTERNOON WITH SNOWFALL RATES OF 2" PER HOUR...IT SHOULD NOT LAST LONG ENOUGH TO GIVE WIDESPREAD TOTALS OVER 10". WE'LL PROBABLY GET SOME THUNDER/LIGHTNING REPORTS WITH THIS AS WELL. CLOSER TO COAST...WE NEED TO DEAL WITH PRECIPITATION TYPE AS WE HAVE NO BLOCKING HIGH TO NORTH TO KEEP COLD AIR LOCKED IN AT LOW LEVELS. WINDS SHOULD EASILY BE ABLE TO TURN SE LATER THIS MORNING...ESPECIALLY SINCE MODELS SHOW 1000 MB AGEOSTROPHIC WINDS TURNING W...NOT A GOOD SIGN TO KEEP IT COLD. GFS CROSS SECTIONS MAY BE A LITTLE TOO WARM...INDICATING A CHANGE TO RAIN AS FAR INLAND AS I-495 IN EASTERN MA AND INTO NW RI. WE THINK IT IS MORE REALISTIC THAT THE TRANSITION ZONE (IE RAIN/SNOW MIX) WILL END UP NEAR I-95 BETWEEN BOSTON AND PROVIDENCE AND PROBABLY AS FAR N AS CAPE ANN. A COMPLETE CHANGE TO RAIN SEEMS MOST LIKELY WITHIN 5-10 MILES OF THE COAST FROM BOSTON TO PLYMOUTH...THEN ACROSS SE MA NEAR TAUNTON AND INTO PROVIDENCE. THAT BEING SAID...WE WILL NUDGE STORM TOTALS DOWN SLIGHTLY IN THESE LOCATIONS. WE CURRENTLY HAVE SE MIDDLESEX AND W NORFOLK COUNTIES IN A LOW-END WINTER STORM WARNING AND THAT STILL SEEMS REASONABLE...AS WE THINK PLACES ALONG ROUTE 128 FROM WOBURN AND BELMONT TO NEWTON AND DEDHAM WILL SEE THE 4-5" AMOUNTS AND LOCATIONS FARTHER INLAND SUCH AS LEXINGTON AND ESPECIALLY MEDWAY AND BELLINGHAM WILL SEE THE 6-8" TOTALS. IN THOSE ZONES WHERE WE HAVE A WINTER WEATHER ADVISORY...WE WILL GENERALLY HAVE 2-4" TOTALS. ONE EXCEPTION TO THIS IS IN COASTAL ESSEX COUNTY MA (ZONE 7)...WHERE WE EXPECT A WIDE RANGE IN TOTALS... FROM 2" ON COASTLINE TO AS MUCH AS 7-8" NEAR NH BORDER. BUT AVERAGE IS LOW ENOUGH TO KEEP AN ADVISORY GOING THERE. HEAVIEST SNOW SHOULD SHIFT INTO MERRIMACK VALLEY EARLY THIS AFTERNOON WHILE SNOWFALL RATES DECREASE BACK ACROSS CT VALLEY. STRONGEST LIFT IS HEADING QUICKLY FOR COAST BY MID AFTERNOON...SO WE THINK MANY LOCATIONS WILL SEE IMPROVING CONDITIONS BY 3 OR 4 PM EXCEPT FOR CAPE COD AND ISLANDS. MAIN CONCERN THEN BECOMES WIND. SURFACE LOW DEEPENING RAPIDLY OFF CAPE COD WILL CAUSE A RAPID INCREASE IN WINDS THROUGHOUT ALL OF REGION...BUT ESPECIALLY NEAR COAST. IF WE TAKE GFS SOUNDINGS FOR HYANNIS AND NANTUCKET AT FACE VALUE IT SHOWS A STRONG POTENTIAL OF 50-60KT GUSTS AS THIS DEEPENING OCCURS LATE THIS AFTERNOON AND EVENING. WE THINK THIS MAY BE A LITTLE HIGH...BUT WE HAVE ENOUGH CONFIDENCE TO ISSUE HIGH WIND WARNINGS AT THIS TIME. WIND ADVISORY WILL BE KEPT IN PLACE FOR S COAST...EVEN THOUGH CONFIDENCE ON 40KT GUSTS THERE IS LESS. ADVISORIES MAY ALSO NEED TO BE ISSUED FOR E MA COASTLINE BUT RIGHT NOW WE THINK WE WILL FALL SHORT OF CRITERIA THERE. CLEARING SHOULD WORK IN RAPIDLY THIS EVENING AS CROSS SECTIONS SHOW RAPID DRYING AND STRONG SUBSIDENCE...BUT WINDS WILL ONLY DIMINISH GRADUALLY UNTIL SYSTEM PULLS FARTHER OFFSHORE. LONG TERM (SATURDAY THROUGH THURSDAY)... OVERALL COLD AIR REMAINS IN PLACE OVER REGION THROUGH AT LEAST THURSDAY. WEAK RIDGE BUILDS OVER REGION SATURDAY IN WAKE OF DEPARTING STORM. SATURDAY NIGHT HEIGHTS BEGIN TO FALL AND WINDS BACK AS CYCLONIC FLOW BEGINS TO TAKE OVER. SHORTWAVES MOVE OVERHEAD THROUGH MONDAY WHILE AT THE SURFACE A DISORGANIZED LOW PRESSURE AREA MOVES ACROSS SOUTHERN QUEBEC TOWARD THE CANADIAN MARITIMES. COLD AIR ADVECTION ACROSS REGION COULD YIELD SHOWERS OVER OUTER WATERS CLIPPING CAPE AND ISLANDS. SURFACE HIGH PRESSURE BUILDS SOUTHEAST FROM CENTRAL CANADA...AND RESULTING N TO NW WINDS OVER CAPE COULD YIELD OCEAN EFFECT SNOW SHOWERS TUESDAY AND WEDNESDAY. RIDGING THROUGH THE COLUMN BUILDS OVER NEW ENGLAND THURSDAY...THEN REGION AWAITS NEXT POTENTIAL NOREASTER FOR FRIDAY. AVIATION... VFR FOR THE MOMENT...EXCEPT FOR MVFR CEILINGS NEAR NANTUCKET WHICH WILL SPREAD ONTO S COAST EARLY THIS MORNING. CONDITIONS WILL DETERIORATE RAPIDLY THIS MORNING TO IFR AS SNOW ARRIVES (THEN TO LIFR WITHIN 2 HOURS OF THAT)...CURRENTLY TIMED INTO CT VALLEY TOWARD SUNRISE AND BEFORE MID MORNING ALONG E MA COAST. CONDITIONS WILL LIFT TO MVFR THIS AFTERNOON AS HEAVIER SNOW SHIFTS OFFSHORE...THEN WE EXPECT RAPID IMPROVEMENT TO VFR BY EARLY THIS EVENING AS LOW PULLS OFF THE COAST. MARINE... WE WILL EXPAND STORM WARNINGS THIS AFTERNOON TO INCLUDE CAPE COD BAY AND NANTUCKET SOUND...AND MAINTAIN GALE WARNINGS ELSEWHERE AS WINDS INCREASE RAPIDLY BEHIND DEPARTING LOW. THERE IS STILL SOME QUESTION AS TO HOW FAST THE LOW WILL DEEPEN...IMPACTING WIND GUST POTENTIAL... BUT IT IS MORE LIKELY IT WILL OCCUR CLOSE ENOUGH TO CAPE COD RATHER THAN FARTHER OFFSHORE. WINDS AND SEAS SLOWLY DIMINISH OVERNIGHT AS SYSTEM PULLS FARTHER AWAY. FOLLOWED WNA WAVE GUIDANCE...HOWEVER GIVEN PREVAILING WEST TO SOUTHWEST WINDS SATURDAY AND SUNDAY...INCREASED SEAS IN BUZZARDS BAY. SMALL CRAFT ADVISORY CONDITIONS EXPECTED OVER THE WEEKEND FOR OUTER WATERS AND ALONG SOUTH COAST...ALL DUE TO WIND GUSTS TO 30 KTS AND ROUGH SEAS. WINDS AND SEAS SUBSIDE MONDAY AND TUESDAY. CLIMATE... FYI...RECORD DAILY SNOWFALL TOTALS FOR TODAY ARE AS FOLLOWS... KBOS... 4.6 INCHES IN 1978 KPVD... 3.0 INCHES IN 1995 KORH... 8.0 INCHES IN 1903 KBDL... 4.2 INCHES IN 1995 .BOX WATCHES/WARNINGS/ADVISORIES... CT...HEAVY SNOW WARNING FOR CTZ002>004 UNTIL 4 PM FRIDAY. MA...HEAVY SNOW WARNING FOR MAZ002>004-008>012 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR MAZ005-006-013-014-026 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR MAZ007-015-016-019>021 UNTIL 1 AM SATURDAY. ...WINTER WEATHER ADVISORY FOR MAZ007-015>019 UNTIL 5 PM FRIDAY. ...HIGH WIND WARNING FOR MAZ022>024 UNTIL 1 AM SATURDAY. NH...HEAVY SNOW WARNING FOR NHZ011 UNTIL 4 PM FRIDAY. ...WINTER STORM WARNING FOR NHZ012-015 UNTIL 5 PM FRIDAY. RI...HEAVY SNOW WARNING FOR RIZ001 UNTIL 4 PM FRIDAY. ...WINTER WEATHER ADVISORY FOR RIZ002>005 UNTIL 5 PM FRIDAY. ...WIND ADVISORY FOR RIZ006>008 UNTIL 1 AM SATURDAY. MARINE...GALE WARNING FOR ANZ230-233>237 UNTIL 1 AM SATURDAY. ...STORM WARNING FOR ANZ231-232-250-254-255 UNTIL 1 AM SATURDAY. $$ SHORT TERM...NOCERA/EVT/NMB ma AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 359 PM EST FRI DEC 9 2005 .DISCUSSION... MAIN FCST CONCERNS ARE -SN CHANCES WITH CLIPPER SYSTEM ON SAT AND POTENTIAL FOR HEAVY LES IN ITS WAKE. WV IMAGERY...RUC ANALYSIS AND 12Z RAOBS CONTINUES TO SHOW SAME PATTERN WITH RDG OVER WRN NOAM AND TROFFING OVER THE EAST RESULTING IN A NW FLOW FROM WRN CANADA INTO THE UPPER GRT LAKES. FEATURE OF INTEREST IS CLIPPER DIVING DOWN FROM ALBERTA WITH ASSOC SFC LOW OVER CNTRL SASKATCHEWAN. 285-290K ISENTROPIC LIFT AHEAD OF THIS SHORTWAVE SUPPORTING SOME LIGHT SNOW OR FLURRIES OVER MANITOBA AND WRN ONTARIO WITH PLENTY OF CLDS FROM CENTRAL CANADA BACK INTO THE NRN PLAINS STATES. AT THE SFC...LOW PRES IS LOCATED JUST NORTH OF LAKE WINNIPEG WHILE A HIGH PRES RDG IS CENTERED OVER THE SRN PLAINS AND LWR MS VALLEY. BETWEEN THESE FEATURES SW GRAD WINDS INCREASING INTO NRN PLAINS AND UPR GREAT LAKES. TONIGHT...AS THE CLIPPER SHORTWAVE DIVES SOUTHEAST INTO SW ONTARIO LATER TONIGHT...SW GRAD WILL CONTINUE TO TIGHTEN OVER UPPER MICHIGAN AS THICKER CLOUDS SPREAD IN FM ONTARIO IN THE EVENING. FCST OF LOW TEMPS IS A CHALLENGE AS TEMPS AFTER THE EVENING HRS MAY TEND TO HOLD STEADY OR EVEN RISE OVERNIGHT DUE TO INCREASE IN CLDS AND WINDS. HOWEVER...DEW POINTS OVER THE AREA ARE STILL QUITE LOW (10 TO 15F RANGE) AND THIS MAY ALLOW FOR TEMPS TO FALL SOME THIS EVENING DESPITE THE WIND. FOR THIS REASON SHADED MIN TEMPS A FEW DEGREES BLO GFS GUIDANCE. SPREAD A CHC OF -S INTO MAINLY WEST AND CENTRAL COUNTIES OVERNIGHT WITH WEAK TO MODEST Q-VECT CONV AND DEEPENING MSTR. SAT...PREFER MORE WESTERLY ECMWF/GFS TRACK WITH SFC LOW WHICH BRINGS SYSTEM ACROSS LAKE SUPERIOR. UPR LVL DIV WITH THE RIGHT ENTRANCE OF 110 KT H3 JET INTO NRN ONTARIO ALONG WITH MODEST QVECTOR CONV WILL BRING INCREASING CHANCES FOR -SN. WHILE MOISTURE INFLOW INTO SYSTEM LOOKS TO BE MINIMAL...SHORTWAVE DYNAMICS SHOULD STILL BE ENOUGH TO SUPPORT WIDESPREAD LIKELY POPS FOR SMALL QPF (LESS THAN A TENTH OF AN INCH) SO...GENERALLY EXPECT SYNOPTIC SNOWFALL AMOUNTS OF INCH OR LESS MOST AREAS EXCEPT MAYBE UP TO TWO INCHES OVER FAR ERN COUNTIES WHERE ISENTROPIC LIFT MAY BE A BIT BETTER INITIALLY. LATE SAT INTO SUN...AS THE SFC LOW/TROF MOVES FROM ERN LK SUPERIOR INTO ACROSS LK HURON...CAA WILL ENSUE BEHIND THE SYSTEM AS 20-30 KT NRLY 950-850 MB WINDS WILL BRING LAKE ENHANCED SNOW FROM WEST UPR MI INTO N CNTRL UPR MI LATE AFTERNOON AND EVENING AS H8 TEMPS DROP INTO THE -8C TO -12C RANGE BTWN 21Z-03Z. THE DEEPER MOISTURE WILL DEPART AFTER 06Z SUN WITH A TRANSITION TO PURE LES AT THAT TIME. CYCLONIC NRLY FLOW WILL FAVOR HIGHER TERRAIN LOCATIONS OVER MQT AND WRN ALGER COUNTIES...GOGEBIC-ONTONAGON AND PORTIONS OF HOUGHTON AND KEWEENAW COUNTIES FOR GREATEST STORM TOTAL ACCUMULATIONS. SNOW GROWTH PARAMETERS ARE FAVORABLE AS WELL WITH MUCH OF CONVECTIVE LYR WITHIN THE -12C TO -17C RANGE. GIVEN FAVORABLE CONDITIONS FOR HEAVY SNOW/BLOWING SNOW HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR NRN HOUGHTON AND KEWEENAW COUNTIES STARTING AT 18Z SAT....FOR SRN HOUGHTON...GOGEBIC AND ONTONAGON COUNTIES STARTING 21Z AND FOR MQT AND ALGER AT 23Z SAT FOLLOWING SOMEWHAT SLOWER TIMING OF GFS. WENT WITH SNOWFALL AMOUNTS OF 4-8 INCHES SAT NIGHT AND ANOTHER 3-5 INCHES SUN IN THE FAVORED LOCATIONS. WILL WORD UP TO A FOOT OF STORM TOTAL ACCUMULATION FOR FAVORED LOCATIONS LATE SAT INTO SUN IN WSW STATEMENT. LOOKING AT GFS AND NAM LES SHOULD TAPER OFF BY MIDDAY SUNDAY AS INVERSION HGTS LOWER BLO 5KFT AND SHEAR INCREASES IN CBL WITH SFC RDG BUILDING INTO THE REGION. HOWEVER...LES COULD LINGER LONGER IF UKMET/ECMWF SCENARIO PANS OUT WHICH WOULD KEEP NWRLY SFC-850 FLOW GOING THROUGH 00Z MON. SUN NIGHT INTO MON...LOOK FOR LES TO BECOME SCT FROM THE WEST SUN EVENING BUT THEN ANOTHER CLIPPER IS DUE TO MOVE THROUGH LATE SUN NIGHT INTO MON WHICH WILL BRING YET ANOTHER CHC OF SNOW. EXTENDED (TUE-FRI)...NOT MUCH CHANGE IN PATTERN INDICATED BY OPERATIONAL MODELS OR ENSEMBLES WITH SERIES OF CLIPPER SYSTEMS TO MOVE THROUGH UPPER GREAT LAKES IN NW FLOW. MODEL TIMING AND POSITION OF THESE SHORTWAVES IS SKETCHY AT BEST SO WILL CONTINUE FCST OF CHC POPS FOR SNOW THROUGH THE WEEK. && .MQT...WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH SAT AFTERNOON INTO SUN MORNING MIZ001-003. WINTER STORM WATCH LATE SAT AFTERNOON INTO SUN MORNING MIZ002-009-084. WINTER STORM WATCH SAT EVENING INTO SUN AFTERNOON MI005-006. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BILLINGS MT 311 PM MST FRI DEC 9 2005 .SHORT TERM...VALID FOR SAT AND SUN... TEMPERATURES HAVE RISEN INTO THE 30S AND 40S OVER THE WESTERN ZONES. SNOW LIKELY HAS LOST POWDERY CONSISTENCY AND WILL NO LONGER BLOW AROUND MUCH...SO HAVE CANCELLED BLOWING SNOW ADVISORY FOR N SWEET GRASS...S WHEATLAND AND JUDITH GAP ZONES. RADAR LOOPS AND SURFACE OBSERVATIONS SHOWED AN AREA OF PRECIPITATION MOVING SE THROUGH NE MT THIS AFTERNOON. PRECIP WAS A MIX OF SNOW AND FZRA AND WAS WEAKENING PER LATEST RADAR TRENDS. EXTRAPOLATION BROUGHT PRECIP INTO FORECAST AREA JUST AFTER 23Z. WENT WITH CHANCE POPS DUE TO WEAKENING RADAR TRENDS AND LATEST RUC NOT SHOWING MUCH PRECIP MAKING IT INTO THE AREA. SHORTWAVE ENERGY WILL CONTINUE RIDING THROUGH THE E OVERNIGHT SO HAVE SPREAD LOW POPS WEST TO KMLS. GFS INITIALIZED A LITTLE BETTER THAN NAM AT 850 MB SO WENT WITH THIS MODEL. GFS TIME-HEIGHTS SUPPORTED A CHANCE OF PRECIP AS FAR W AS KMLS ALL NIGHT. WILL LEAVE OUT FZRA FOR NOW AS BUFKIT HAD TEMPS BELOW ZERO ALOFT OVER KBHK SO THERMAL PROFILE DID NOT SUPPORT FREEZING RAIN. GFS DID NOT SUPPORT A THREAT OF HIGH WINDS IN THE E TONIGHT. 850 WARM AIR ADVECTION WILL KEEP LOW LEVELS STABLE AND PRESSURE RISES WILL NOT BE VERY STRONG. ALSO UVV WILL PREVAIL OVER THE E DUE TO THE SHORTWAVES. THUS WILL NOT NEED WIND HIGHLIGHTS OVER THE E. OVER GAP FLOW AREAS HOWEVER...PRESENCE OF NW-SE ORIENTED 700 MB JET...STRONG PRESSURE GRADIENT AND STABLE LOW LEVELS WILL CONTINUE TO SUPPORT ADVISORY WINDS OVERNIGHT. KLVM HAS MET ADVISORY CRITERIA MANY TIMES THIS AFTERNOON. SPORADIC REPORTS FROM STILLWATER MINE INDICATED GUSTS NEAR ADVISORY CRITERIA SO WILL LET ADVISORY RIDE THROUGH 12Z SAT. AFTER 12Z...700 MB JET EXITS AREA AND PRESSURE GRADIENT RELAXES SO WOULD NOT EXPECT A CONTINUATION OF ADVISORY WINDS. OTHERWISE SAT THROUGH SUN NIGHT WILL BE DRY WITH A WARMING TREND AS HIGH PRESSURE RIDGE SHIFTS EAST. MADE MINOR CHANGES TO TEMPS TO ACCENTUATE WARMING TREND. ARTHUR .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... UPPER TROUGH MOVES INTO THE AREA LATE MONDAY WITH NORTHWEST FLOW SETTING UP BEHIND THE TROUGH TUESDAY. THIS NORTHWEST FLOW WILL PERSIST THROUGH THE EXTENDED WITH ACTIVE AND COOLER WEATHER THE RESULT FOR SOUTHERN MONTANA. MODELS CONTINUE TO HINT AT AN ARCTIC SHOT FOR THE END OF THE WEEK WITH TEMPERATURES WELL BELOW NORMAL AGAIN EXPECTED. GOING FORECAST ALREADY UNDER CUTTING GUIDANCE CONSIDERABLY FOR THE END FORECAST PERIOD AND THIS LOOKS GOOD STILL SO MADE VERY FEW CHANGES TO TEMPERATURES WITH THIS PACKAGE. NORTHWEST FLOW ALOFT TO ALSO BRING A SERIES OF WAVES THROUGH THE AREA DURING THE EXTENDED WITH SNOW SHOWERS POSSIBLE EVERY PERIOD FROM MONDAY NIGHT ON. THIS ALSO LOOKS GOOD AND WILL LEAVE POPS AS IS FOR NOW WITH UNCERTAINTY IN TIMING OF WAVES RESULTING IN LOW CONFIDENCE IN ADDING LIKELY POPS TO AREAS AT THIS TIME. MACZKO && .AVIATION... GUSTY WINDS WILL PERSIST IN THE VICINITY OF KLVM AND THE LEE OF THE BEARTOOTH MOUNTAINS THROUGH FRIDAY MORNING...WITH LOCALIZED BLOWING SNOW REDUCING VISIBILITIES TO MVFR AT TIMES TONIGHT. ISOLATED SNOW SHOWERS OVER EXTREME EASTERN MONTANA WILL RESULT IN OCCASIONAL IFR CONDITIONS THROUGH 06Z TONIGHT. OTHERWISE...VFR CONDITIONS WILL PREVAIL OVER THE AREA. MACZKO && .PRELIMINARY POINT TEMP/POPS... SAT SUN MON TUE WED THU FRI ----------------------------------------------------------- BIL 025/041 022/046 026/043 024/033 017/027 011/024 012/023 00/N 00/N 00/B 03/S 33/S 23/S 33/S LVM 025/044 023/047 021/043 023/033 014/025 012/023 010/022 00/N 00/N 00/N 23/S 33/S 33/S 33/S HDN 020/039 019/045 021/044 020/033 016/027 014/025 012/021 00/B 00/U 00/B 03/S 33/S 23/S 33/S MLS 018/037 017/040 017/038 015/031 013/026 009/022 006/018 40/B 00/B 00/B 03/S 33/S 23/S 32/S 4BQ 022/039 016/042 019/044 017/033 013/027 010/021 008/022 20/N 00/B 00/B 03/S 33/S 23/S 32/S BHK 023/034 016/037 016/037 016/028 011/024 007/020 006/019 41/M 00/N 00/B 03/S 33/S 23/S 32/S SHR 017/040 016/044 016/041 016/034 012/029 010/025 008/024 00/N 00/U 00/B 03/S 33/S 23/S 33/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WIND ADVISORY IN EFFECT UNTIL 5 AM MST SATURDAY FOR ZONES 65-66. WY...NONE. && $$ WEATHER.GOV/BILLINGS mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 255 PM CST FRI DEC 9 2005 .SHORT TERM...CHALLENGING FORECAST WITH CLIPPER SYSTEM TO PASS JUST NE OF FA. MODELS HANDLE PROGRESSION OF SYSTEM COMPARABLY BUT ENOUGH DIFFERENCES TO CAUSE A HEADACHE. WILL LEAN TOWARD NAM FOR LOW LEVEL TEMPS...WHICH MAY EVEN BE TOO COOL WITH RUC INDICATING POCKET OF 925MB TEMPS ABOUT 3C WARMER THAN NAM...PUSHING FURTHER E THAN NAM IS INDICATING. GFS IS WAY TOO COOL AT LOW LEVELS...AS HAS BEEN THE THEME. CANADIAN RADAR IMAGERY SHOWING STRONGER RETURNS N OF ND AHEAD OF 500MB TROUGH AXIS...WHICH WILL MOVE TOWARD FA BY THIS EVENING. BEST PVA (LIFT) WILL BE ACROSS N FA TONIGHT...ALTHOUGH QPF REMAINS POSSIBLE ACROSS ENTIRE FA AS 500MB TROUGH AXIS SWINGS THROUGH. CONSIDERING CURRENT SFC TEMPS ACROSS W FA...EXPECTED CLOUD COVER...AND BEST COLD AIR ADVECTION NOT OCCURRING UNTIL AFT 12Z SFC TEMPS OVERNIGHT WILL BE AT OR NEAR FREEZING ALONG AND W OF VALLEY. THIS LEADS TO FREEZING RAIN/DRIZZLE POTENTIAL. WILL GO COMBO -RA/FZDZ OR -SN/FZDZ THIS AREA THROUGH TONIGHT. E OF VALLEY SHOULD REMAIN ALL SNOW...BUT MONITORING PROGRESSION OF LOW LEVEL WARM AIR WILL BE NEEDED. NEXT CONCERN IS WIND POTENTIAL. BEST 850MB WIND SPEED CORE TO BE ACROSS CENTRAL ND INTO W FRINGE OF FA AROUND 06Z. WITH THIS...W FA (W OF VALLEY) WILL SEE AROUND 30MPH SUSTAINED WINDS AFT MIDNIGHT. THERE MAY BE A QUICK SHOT OF STRONGER COLD AIR ADVECTION...BUT FOR THE MOST PART COLD AIR ADVECTION WILL BE WEAK AND DO NOT EXPECT DEEP MIXING POTENTIAL...ALTHOUGH WITH 45 KTS TO MIX WILL BE WINDY. THUS EXPECTING NEAR ADVISORY CRITERIA (30KT)...NOT MUCH MORE. BEST SNOW COVER SOUTH OF A BDE-GFK-JMS LINE. WINDY CONDITIONS WILL REMAIN W OF VALLEY UNTIL TOMORROW MORNING...AND WILL DEFER HEADLINES ALONG AND E OF VALLEY FOR NEXT SHIFT AS ANY ADVISORY POTENTIAL WILL NOT BE UNTIL AFT 12Z. ACROSS DVL BASIN INTO EXTREME N VALLEY (WHERE BEST POTENTIAL FOR QPF EXISTS)...WITH FREEZING PRECIP POTENTIAL/WINDY CONDITIONS/AND POSSIBLE BLOWING SNOW WHERE THERE IS SNOW WILL GO WINTER WX ADVISORY TONIGHT. SOUTH OF THIS AND W OF VALLEY...WILL GO BLOWING SNOW ADVISORY WITH WINDY CONDITIONS BLOWING AROUND SNOW AND REDUCING VSBY. WINDY CONDITIONS TO PERSIST INTO SAT AFTERNOON...DECREASING BY EVENING AS THE SYSTEM MOVES OFF. EXPECTED COLD AIR ADVECTION MAY MEAN FALLING TEMPS DURING THE DAY. A SIMILIAR SYSTEM AFFECTS THE REGION SUNDAY. NW FLOW ALOFT WILL CONTINUE INTO MONDAY WITH SLIGHT SNOW CHANCES CONTINUING. .LONG TERM...COLD AND UNSETTLED WEATHER PATTERN TO DOMINATE WEATHER OVER THE NOR PLAINS THROUGH THE PERIOD. STRONG AMPLIFIED DOMINATE NORTHERN STREAM JET IS EXPECTED TO CARVE OUT POTENT 500MB LOW OVER THE NORTHERN PLAINS STATES TUESDAY NIGHT INTO WEDNESDAY. THIS FEATURE SHOULD BRING DESCENT SHOT OF SNOW TO REGION WITH POTENTIAL FOR SEVERAL INCHES ALONG WITH INCREASING PRESSURE GRADIENT I.E. BLOWING AND DRIFTING SNOW. IN WAKE OF FEATURE PATTERN WILL CONTINUE ACTIVE WITH NEXT S/W TROUGH SLATED FOR FRIDAY WITH ADDITIONAL SNOW CHANCES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SATURDAY FOR NDZ006-NDZ007-NDZ008-NDZ014-NDZ015-NDZ016- NDZ024-NDZ026-NDZ054. BLOWING SNOW ADVISORY FROM MIDNIGHT TONIGHT TO 12 PM CST SATURDAY FOR NDZ028-NDZ029-NDZ038-NDZ049-NDZ052. MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SATURDAY FOR MNZ004-MNZ007. && $$ TG/BERG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1220 PM EST FRI DEC 9 2005 .SHORT TERM (REST OF TODAY)... BUSY WEATHER SITUATION WITH SYSTEM PASSING OUT OF STATE. SYSTEM DROPPED AN AVERAGE OF 7-8 INCHES OVER MOST OF CWA BUT SOME REPORTS OF OVER 10 INCHES ALSO RECEIVED. AVIATION FORECASTS CONDITIONS HAVE BEEN RAPIDLY CHANGING THIS MORNING AS WINDS HAVE PICKED UP AND A LOT OF BLOWING SNOW COMBINED WITH SNOW SHOWERS AND FOG. RAPIDLY CHANGING CONDITIONS AT BOTH JST AND BFD BUT AREAS TO THE EAST ARE A BIT MORE STABLE. WIND GUSTS HAVE BEEN AS HIGH AS 35KTS THUS BLOWING SNOW HAS BEEN QUITE SIGNIFICANT IN CWA. TRAVEL CONDITIONS DUE TO THIS SNOW ARE POOR DUE TO THE REDUCED VISIBILITIES AND THEIR RAPID CHANGES. CURRENT FORECAST IN DECENT SHAPE AFTER EARLIER MORNING UPDATE...THUS WILL LET IT RIDE. && .PREVIOUS DISCUSSION... (ISSUED 255 AM EST FRI DEC 9 2005) SHORT TERM (TODAY THROUGH SATURDAY)... MODERATE TO HEAVY SNOW CURRENTLY FALLING OVR BULK OF CENTRAL PA IN ADVANCE OF UPPER LO ROTATING THRU OHIO VALLEY. ASSOCIATED SOUTHERLY LL JET (70KTS ON KCCX VWP)...PRODUCING A 6-8HR PERIOD OF STRONG WAA EARLY THIS AM. HOWEVER...BACK EDGE OF SNOW ALREADY ENTERING WESTERN PA. LATEST RUC ENDS STEADY SNOW BEFORE DAWN ACROSS ALL BUT SUSQ VALLEY. DESPITE THE DRY NATURE OF THE SNOW...THE SNOW:WATER RATIO MEASURED AT PSU LAST HOUR WAS 8:1...WHICH SEEMS REASONABLE GIVEN THAT MAX OMEGA OCCURRING ARND -6C. HOWEVER...PREVIOUS FCST OF A GENERAL 5-8 INCHES STILL SEEMS ON TRACK GIVEN SNOW REPORTS SO FAR AND LATEST RADAR TRENDS. UPSLOPING FLOW WILL PRODUCE LINGERING SNOW SHWRS OVR THE MTNS. HOWEVER...EXPECT LITTLE ADDITIONAL ACCUMS AS INVERSION ONLY EXPECTED ARND 800 MB. THE LARGER ISSUE WILL BE BLOWING AND DRIFTING SNOW IN OPEN AREAS LATER TODAY. AS COASTAL LOW DEVELOPS S OF NEW ENGLAND...WEST WINDS WILL BECOME STRONG BY AFTN WITH GUSTS LIKELY CLOSE TO 40MPH BASED ON MODEL SOUNDINGS. LEANED TOWARD COLDER MET READINGS TONIGHT BASED ON FRESH SNOW COVER AND DIMINISHING WINDS LATE TONIGHT AS HI PRES BUILDS IN. AFTER A COLD START...SW FLOW AND PLENTY OF SUNSHINE SHOULD ALLOW TEMPS TO RECOVER TO NR NORMAL READINGS BY SAT AFTN. LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)... A SERIES OF WEAK CLIPPER SYSTEMS PASSING TO OUR NORTH NOT LIKELY TO BRING SIG PRECIP TO OUR AREA. HOWEVER...EACH SHOULD REINFORCE THE CHILL OVER OUR REGION. LOOKS RELATIVELY DRY BUT COLD FOR MOST OF NEXT WEEK. AVIATION... WIDESPREAD IFR CONDITIONS THIS MORNING IN MODERATE TO HEAVY SNOW...TAPERING TO LIGHTER SNOW BY MID MORNING...FROM WEST TO EAST. MUCH OF THE DAY WILL BE MVFR IN SC...BUT VFR CONDITIONS EXPECTED LATER THIS AFTERNOON...AS THE STORM PULLS AWAY...AND HIGH PRESSURE BUILDS NORTHWARD. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ONDREJIK pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 347 PM CST FRI DEC 9 2005 .SHORT TERM...TONIGHT THROUGH MONDAY NIGHT DIFFICULT SHORT TERM SETTING UP DURING NEXT 24 HRS AS WAVE APPROACHES FROM THE NW. SEEMS THAT NAM AND RUC HAVE A BETTER HANDLE ON LOW LEVEL TEMPS SO USED AS FORECAST BASIS FOR TONIGHT THROUGH SAT NIGHT. MAJOR CONCERNS INCLUDE LOW TEMPS AND FREEZING PRECIP. MID LEVEL WAVE APPROACHING FROM THE NW THIS AFTERNOON WITH MILD AIR BEING PUMPED INTO THE DAKOTAS. GFS SEEMS TO BE TOO COLD SO HAVE FOLLOWED A MORE REASONABLE NAM AND RUC SOLUTION. FIRST OFF TEMPS...FEEL THAT TEMPS WILL NOT DROP OFF MUCH TONIGHT AT ALL FROM LATE AFTERNOON/EARLY EVENING READINGS. RUC/NAM STILL SHOWING WAA INTO THE NIGHT HRS WITH THERMAL RIDGE SITTING ON TOP OF US STILL AT 03Z. AS SFC TROUGH MOVES THROUGH LATER TONIGHT...WINDS WILL KICK UP OUT OF THE WEST AND FEEL TEMPS WILL ACTUALLY RISE A BIT OVERNIGHT...POSSIBLY EVEN INTO THE 30S. 8D3 WILL PROBABLY SEE SOME MILD TEMPS OVERNIGHT ONCE SFC WINDS SWITCH MORE WESTERLY. TEMPS WILL HAVE TO BE MONITORED CLOSELY THIS EVENING. AS WEAK CAA KICKS IN BY MORNING SHOULD SEE TEMPS COOL A FEW DEGREES. SECONDLY...INSERTED CHANCE FOR LIGHT FREEZING RAIN TONIGHT...WITH THE THREAT ENDING SHORTLY AFTER MIDNIGHT. SOUNDINGS SHOW A NICE ABOVE FREEZING LAYER AROUND 850MB...ALTHOUGH NOT TOO MUCH MOISTURE PRESENT TO GET TOO EXCITED ABOUT. UPSTREAM OBS IN ND/MT SHOW GOOD AREAL COVERAGE OF PRECIP AND HAVE COME IN WITH LGT FRZ RAIN OR IP THROUGHOUT THE DAY. NAM IS SHOWING LIFT PRESENT AS 700MB WAVE SWINGS THROUGH. THOUGHT ABOUT BLOWING SNOW ADVISORY FOR SAT BUT HAVE DECIDED TO HOLD OFF FOR RIGHT NOW. STILL EXPECTING QUITE BREEZY CONDITIONS TOMORROW. SNOW IS STILL RATHER FLUFFY ACROSS THE AREA WHICH COULD BLOW AROUND EASILY. ALSO WEIGHED FACTORS OF HOW OLD THE SNOW WAS AND TODAYS TEMPS. MANY LOCATIONS RECEIVED PLENTIFUL SUNSHINE TODAY AND TEMPS NEARING 30. THIS PROBABLY BEGAN TO MELT TOP LAYER OF SNOW JUST ENOUGH SO THAT AFTER SUNSET WHEN IT FREEZES AGAIN IT WILL HARDEN SOME. SO HAVE THEREFORE HELD OFF ON ANY HEADLINES AT THIS TIME BUT WILL HAVE TO EXAMINE LATER. REST OF SHORT TERM CHANGED LITTLE AS CWA REMAINS IN NW FLOW ALOFT AND TEMPS REACH NORMAL LEVELS. .LONG TERM...TUESDAY THROUGH FRIDAY MODELS CONTINUE TO BE IN A STATE OF DISAGREEMENT...WITH ONLY MINOR SIMILARITIES NOTED BETWEEN ANY OF THEM. THEY DO AGREE ON A STORM SYSTEM TRACKING ACROSS THE REGION FROM LATE TUESDAY THROUGH THE DAY THURSDAY...BUT NO AGREEMENT AS TO EXACTLY WHERE OR HOW STRONG. FOR THIS REASON...HAVE MADE VERY FEW CHANGES TO THE GOING EXTENDED PERIOD. WILL KEEP THE MENTION OF SNOW FROM TUESDAY EVENING THROUGH THE DAY THURSDAY...WITH THE REST OF THE PERIOD DRY AS HIGH PRESSURE MOVES IN THURSDAY NIGHT AND FRIDAY. DID RAISE POPS A BIT AROUND MID WEEK AS ANY SOLUTION YOU LOOK AT HAS PRECIPITATION OCCURRING ON WEDNESDAY. NO CHANGES MADE TO TEMPERATURES. STAYED BELOW GUIDANCE AS WE WILL STILL BE DEALING WITH AN ABUNDANCE OF SNOW COVER...BOTH THE STUFF ALREADY ON THE GROUND AND THE POTENTIAL FOR MORE TO OCCUR DURING THE EXTENDED PERIOD. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ TT/AP sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 1117 AM CST FRI DEC 9 2005 .AVIATION... DECK AROUND 850MB CONTINUES TO STREAM NORTH AND THEN EAST ACROSS THE SOUTHEAST COUNTIES THIS AFTERNOON...BUT SHOULD REMAIN WELL TO THE SOUTHEAST OF KSJT AND KABI. OUR TAF SITES SHOULD SEE NOTHING MORE THAN A FEW HIGH CLOUDS...WITH SOUTH WINDS INCREASING INTO THE 10 TO 14 KNOT RANGE. && .PREV DISCUSSION... (ISSUED 933 AM CST FRI DEC 9 2005) UPDATE... QUICK UPDATE THIS MORNING TO ACCOUNT FOR CURRENT CLOUD TRENDS. CLOUD DECK AROUND 850 MB CLOUDS CONTINUES TO STREAM NORTH ACROSS SOUTH AND CENTRAL TEXAS...AND IS NOW FLIRTING WITH MY SOUTHEAST COUNTIES. LATEST RUC SEEMS TO HAVE HAD A DECENT HANDLE ON IT AND WILL USE IT AS A ROUGH GUIDANCE FOR THE REST OF TODAY. HAVE INCREASED CLOUD COVER TODAY ACROSS MAINLY KIMBLE...MASON...AND SAN SABA COUNTIES...AND LOWERED AFTERNOON HIGHS IN THOSE SAME AREAS. IF CLOUD DECK HANGS IN TOUGH THROUGH THE DAY...INSTEAD OF COMING IN FOR AWHILE AND THEN BREAKING UP BY LATE IN THE AFTERNOON...MAY HAVE TO KNOCK TEMPS DOWN EVEN MORE. PREV DISCUSSION... (ISSUED 516 AM CST FRI DEC 9 2005) AVIATION... EXPECT VFR CONDITIONS...WITH SOUTH WINDS IN THE 5 TO 10 KT RANGE...TO CONTINUE ACROSS WEST CENTRAL TEXAS FOR THE NEXT 24 HOURS. 23/HUBER PREV DISCUSSION... (ISSUED 306 AM CST FRI DEC 9 2005) SHORT TERM... THIS MORNING...UPPER LOWS SITUATED OVER THE GREAT LAKES REGION AND JUST OFF THE CALIFORNIA COAST WITH CLEAR SKIES OVER THE CWA. AFTER ANOTHER COLD START TO THE MORNING...AFTERNOON TEMPS WILL AVERAGE AROUND 15 DEGREES WARMER THAN YESTERDAY. UPPER DISTURBANCE FORMING OVER THE CENTRAL PLAINS TODAY WILL MOVE QUICKLY EAST AND WILL BE ABSORBED INTO THE MAIN UPPER FLOW...ONLY EFFECT ON OUR WEATHER WILL BE A WEAK COLD FRONT PUSHING THROUGH THE AREA ON SATURDAY AFTERNOON. LONG TERM... UPPER RIDGE WILL BUILD INTO OUR AREA ON SUNDAY AHEAD OF THE UPPER LOW MOVING INTO CALIFORNIA. NORTH WINDS WILL SHIFT BACK TO THE SOUTH DURING THE DAY ON SUNDAY WITH AFTERNOON TEMPS INTO THE 60S. UPPER LOW OVER CALIFORNIA WILL BE SHEARED INTO THE UPPER FLOW MIDWEEK WITH ANOTHER WEAK COLD FRONT PUSHING THROUGH THE AREA ON TUESDAY. MORE SIGNIFICANT COLD FRONT TO PUSH THROUGH THE AREA DURING THE DAY ON THURSDAY WITH GOOD PREFRONTAL WARMING ON WEDNESDAY WELL INTO THE 60S. AT THIS TIME...WITH LIMITED MOISTURE TO WORK WITH IN OUR AREA ANY RAINFALL CHANCES LOOK SLIM. SJT WATCHES/WARNINGS/ADVISORIES... NONE. $$ SJT WATCHES/WARNINGS/ADVISORIES... NONE. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07 tx