AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 346 AM EST WED JAN 2 2008 ...COLDEST TEMPERATURES SINCE JANUARY 2003... .SHORT TERM...EXITING AREA OF SURFACE LOW PRESSURE IS NOW CENTERED JUST OFFSHORE OF MAINE...WITH THE COLD FRONTAL BOUNDARY EXTENDING THROUGH THE ATLANTIC WATERS AND SOUTH OF FLORIDA. SURFACE HIGH PRESSURE OVER THE ROCKY MOUNTAINS IS BEGINNING ITS SHIFT SOUTHWARD TOWARDS THE SOUTHERN PLAINS. SIGNIFICANT POLAR JET IS DIGGING INTO THE UPPER TROUGH ALONG THE ATLANTIC COAST... AMPLIFYING THE TROUGH AND HIGH PRESSURE OVER THE PLAINS. THIS UNUSUALLY DRY AND COLD AIR HAS MADE ITS WAY INTO THE SOUTHEASTERN UNITED STATES...WITH SIGNIFICANT DRYING SHOWN ON SATELLITE IMAGERY AND IN CURRENT OBSERVATIONS WITH DEW POINTS DROPPING INTO THE TEENS. WINDS BRIEFLY DECREASED TONIGHT...ALTHOUGH THE RUC13 HAS DONE AN EXCELLENT JOB IN PICKING UP THE SLIGHT TIGHTENING IN THE PRESSURE GRADIENT ALONG THE FLORIDA COAST. THIS TIGHTENED GRADIENT HAS INCREASED WINDS IN THESE AREAS THIS MORNING...WITH SUSTAINED WIND SPEEDS OF 10 TO 15 MPH GUSTING TO 25. FOR TODAY...PRESSURE GRADIENT WILL BE STRONGEST TODAY BETWEEN THE AMPLIFYING TROUGH AND AREA OF HIGH PRESSURE TO THE WEST. THIS WILL LEAD TO SUSTAINED NORTHWESTERLY WINDS NEAR 20 MPH WITH FREQUENT GUSTS UP TO 35 MPH. HIGH TEMPERATURES WILL BE NEARLY 20 DEGREES BELOW CLIMATOLOGICAL NORMALS...AND WIND CHILL VALUES WILL BE IN THE 30S FOR MOST OF THE AFTERNOON. SIGNIFICANT DRYING AND WINDS WILL ALSO CREATE DANGEROUS FIRE WEATHER CONDITIONS TODAY...IN ADDITION TO GALES OVER THE COASTAL WATERS. FOR WEDNESDAY NIGHT AND THURSDAY MORNING...850 MB PLOT TELLS THE STORY WITH VERY DRY CONTINENTAL NORTH TO NORTHWESTERLY FLOW AND SIGNIFICANT COLD AIR ADVECTION. THURSDAY MORNING MINIMUM TEMPERATURES WILL COME CLOSE TO RECORDS...IF NOT BREAKING THEM. HAVE UPGRADED THE HARD FREEZE WATCH TO A WARNING...AS MOST LOCATIONS WILL BE BELOW CRITERIA FOR SEVERAL HOURS. BY EARLY MORNING AND EARLY AFTERNOON LOW LEVEL FLOW WILL SWITCH TO THE NORTHEAST ALONG THE COAST...INCREASING LOW LEVEL MOISTURE. THIS INCREASE IN LOW LEVEL MOISTURE COMBINED WITH COOL 850 MB TEMPERATURES WILL LEAD TO ISOLATED FLURRIES ALONG THE COAST OF ST JOHNS AND FLAGLER COUNTIES...WHERE MOISTURE AND SURFACE CONVERGENCE WILL BE GREATEST. BY AFTERNOON QUICKLY WARMING TEMPERATURES WILL MELT MOST FREEZING PRECIP THAT FALLS...MAKING SPRINKLES THE PREDOMINANT PRECIP TYPE. SINCE MOISTURE WILL BE SO LIMITED...DO NOT EXPECT ANY SIGNIFICANT IMPACTS FROM THESE FLURRIES. ALL HAZARDS ISSUED BY PREVIOUS SHIFT APPEAR TO BE ON TRACK...SO WILL NOT MAKE ANY OTHER CHANGES AT THIS TIME. .LONG TERM...BY FRIDAY HIGH PRESSURE WILL SHIFT TO THE MID ATLANTIC STATES...LEADING TO A PREDOMINANT ONSHORE FLOW. THIS WILL ALLOW TEMPERATURES AND MOISTURE TO REBOUND ACROSS THE AREA...WITH THE MOST SIGNIFICANT INCREASES ALONG THE COAST. A DEVELOPING TROUGH OF LOW PRESSURE OVER THE ROCKY MOUNTAINS WILL WEAKEN AND SHIFT THE AREA OF HIGH PRESSURE OVER THE ATLANTIC WATERS...FINALLY WEAKENING WINDS AND ALLOWING TEMPERATURES TO REACH NORMAL VALUES. AS THIS TROUGH CONTINUES TO APPROACH THE AREA...A SWITCH TO A SOUTHEASTERLY TO SOUTHERLY FLOW WILL LEAD TO WARM AIR ADVECTION AND ABOVE NORMAL TEMPERATURES FOR SUNDAY AND EARLY NEXT WEEK. && .AVIATION...VFR CONDITIONS PREVAIL. LOW LEVEL WIND SHEAR IS EXPECTED UNTIL 14Z WHEN NW WINDS INCREASE TO 15-20 KT WITH GUSTS TO 30 KT. LLWS IS ANTICIPATED AGAIN LATE THIS EVENING. && .MARINE...GALE WARNINGS CONTINUE. BUOYS HAVE BEEN REPORTING FREQUENT GUSTS TO GALE FORCE AND SUSTAINED WINDS 25-30 KT. GALES WILL DIMINISH OVER NEAR SHORE WATERS LATE THIS AFTN AND OFFSHORE TONIGHT. WINDS WILL VEER TO NORTH THURSDAY WITH SCA REPLACING GALE WRNG THEN WINDS BECOME ONSHORE THROUGH THE WEEKEND. && .FIRE WEATHER...NO CHANGES TO RED FLAG HEADLINES ATTM. EXTREMELY DRY CONDITIONS WILL CONTINUE THRU THURS. DEWPOINTS WILL BE IN THE SINGLE DIGITS OVER A LARGE PORTION OF THE AREA THIS AFTN. ONSHORE FLOW BEGINS MOISTENING UP THE ERN PORTION FRIDAY AND BY THE WEEKEND...MINIMUM RH VALUES WILL BE WELL ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... AMG 42 19 48 22 / 0 10 10 0 SSI 43 26 46 31 / 0 10 10 0 JAX 44 20 47 27 / 0 10 10 0 SGJ 45 26 48 37 / 0 20 20 10 GNV 44 18 50 26 / 0 10 10 0 OCF 45 19 50 29 / 0 10 10 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...HARD FREEZE WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER- GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE- UNION. LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM EST THIS EVENING FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-GILCHRIST- HAMILTON-MARION-PUTNAM-SUWANNEE-UNION. LAKE WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR DUVAL- FLAGLER-NASSAU-ST JOHNS. RED FLAG WARNING FROM 10 AM THIS MORNING TO 7 PM EST THIS EVENING FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL- FLAGLER-GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS- SUWANNEE-UNION. WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR ALACHUA- BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER-GILCHRIST- HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE-UNION. FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY AFTERNOON FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL- GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-SUWANNEE-UNION. FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR ALACHUA-BRADFORD- CLAY-DUVAL-MARION-NASSAU-PUTNAM-UNION. FREEZE WARNING UNTIL 8 AM EST THIS MORNING FOR ST JOHNS. HARD FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR BAKER- COLUMBIA-GILCHRIST-HAMILTON-SUWANNEE. GA...HARD FREEZE WARNING UNTIL 10 AM EST THIS MORNING FOR APPLING- ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE-ECHOLS-JEFF DAVIS-PIERCE-WARE-WAYNE. HARD FREEZE WARNING FROM 7 PM THIS EVENING TO 10 AM EST THURSDAY FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN-COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE. LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM EST THIS EVENING FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH- COFFEE-ECHOLS-JEFF DAVIS-PIERCE-WARE-WAYNE. FIRE WEATHER WATCH THURSDAY AFTERNOON FOR APPLING-ATKINSON-BACON- BRANTLEY-CHARLTON-CLINCH-COFFEE-ECHOLS-JEFF DAVIS-PIERCE- WARE-WAYNE. RED FLAG WARNING FROM NOON TODAY TO 5 PM EST THIS AFTERNOON FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN-COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE. WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR APPLING- ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN- COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE. LAKE WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR COASTAL CAMDEN-COASTAL GLYNN-INLAND CAMDEN-INLAND GLYNN. AM...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM. && $$ HURLBUT/TRABERT fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 842 PM EST TUE JAN 1 2008 .UPDATE... BEGINNING TO GET REPORTS OF SNOW FLURRIES IN ROME AND CANTON AREAS. LATEST SATL LOOP SHOWS THIS THREAT WILL LIKELY SWING ACROSS MOST OF THE NORTHERN THIRD OF GA...BUT AREA TEMPS WILL PREVENT ACCUMULATIONS AT THIS TIME. HOWEVER...AS TEMPS LOWER...SOME MINOR ACCUMULATIONS COULD BEGIN TO OCCUR LATER TONIGHT...IN THE HIGHER ELEVATIONS. HAVE UPDATED ZONES TO BRING SLIGHT CHANCE OF SNOW SHOWERS DOWN TO HARALSON...PAULDING...COBB... EXTREME NORTH FULTON... FORSYTH... HALL...AND BANKS COUNTIES THRU THIS EVENING...THEN THE SNOW CHANCES DIMINISH FROM WEST TO EAST THRU EARLY WEDNESDAY MORNING AS THE UPPER IMPULSE SWINGS EAST. OTHERWISE...REST OF FORECAST LOOKS ON TRACK AT THIS TIME. /39 --------------------------PREVIOUS DISCUSSION-------------------- .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... STRONG AREA OF HIGH PRESSURE PRESSING SOUTHEASTWARD OUT OF CANADA WILL CONTINUE TO USHER IN STRONG WINDS AND A COLDER AIR MASS THROUGH THURSDAY NIGHT. HENCE...FORECAST WILL REMAIN DRY THROUGH THE PERIOD. AS A RESULT OF HIGH WINDS...ADVISORY TO REMAIN IN EFFECT THROUGH WEDNESDAY...AND HARD FREEZE WARNING TONIGHT FOR TEMPERATURES EXPECTED TO DROP INTO THE TEENS AND 20S OVER THE NORTHERN MOUNTAINS. .LONG TERM /FRIDAY THROUGH TUESDAY/... HIGH SLIDES EAST OF CWA FRIDAY ALLOWING A MODERATION IN HE AIR MASS...HENCE A RISE IN TEMPERATURES. PREVIOUS GFS RUN (06Z) HAD PRECIPITATION IN FORECAST FOR SATURDAY AND SUNDAY. 12Z RUN WAS MUCH WEAKER...BUT SOME MOISTURE STILL SHOWN. MUCH UNCERTAINTY ABOUT PERIOD...SO LEFT SLIGHT CHC OF RAIN IN FORECAST. && .AVIATION... MOISTURE ASSOCIATED WITH THE DEEP UPPER TROF OVER THE EASTERN PART OF THE COUNTRY CONTINUED TO SAG FARTHER SOUTH TUESDAY AFTERNOON...AND COVERED THE TENNESSEE VALLEY LATE IN THE AFTERNOON. WITH CLOUD BASES AT OR ABOVE 5 THOUSAND FEET...THE MOUNTAINS WILL PROBABLY NOT HOLD THE CLOUDS BACK AS UPPER SHORT WAVE SWINGS THROUGH THE BASE OF THE TROF TONIGHT. LOOKING FOR SCATTERED CLOUDS WITH BASES BETWEEN 4 AND 6 THOUSAND FEET...WITH A PERIOD OF BROKEN CLOUDS IN THE KATL AND KAHN AREAS. BOTH THE RUC AND NAM ARE BEING USED TO HELP WITH TIMING. SCATTERED CLOUDS MAY LINGER AFTER THE MAIN UPPER SHORT WAVE PASSES. WIND SPEEDS MAY EBB AT TIMES OVERNIGHT...BUT GRADIENT REMAINS STRONG AND BECOMES EVEN STRONGER TOWARD DAYBREAK. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 25 41 18 44 19 / 0 5 0 5 5 ATLANTA 22 37 19 41 22 / 0 0 0 5 5 BLAIRSVILLE 21 31 15 41 13 / 30 10 0 5 5 CARTERSVILLE 23 35 15 41 16 / 0 0 0 5 5 COLUMBUS 27 42 21 49 22 / 0 0 0 5 5 GAINESVILLE 23 35 17 42 19 / 0 5 0 5 5 MACON 28 44 20 49 20 / 0 0 0 5 5 ROME 22 38 15 45 14 / 0 0 0 5 5 PEACHTREE CITY 21 36 14 44 9 / 0 0 0 5 5 VIDALIA 25 43 17 49 19 / 0 0 0 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM EST WEDNESDAY FOR THE FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BUTTS...CARROLL... CATOOSA...CHATTAHOOCHEE...CHATTOOGA...CHEROKEE...CLARKE... CLAYTON...COBB...COWETA...CRAWFORD...DADE...DAWSON...DEKALB... DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GLASCOCK...GORDON...GREENE...GWINNETT...HALL...HANCOCK... HARALSON...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER... JONES...LAMAR...LUMPKIN...MACON...MADISON...MARION... MERIWETHER...MONROE...MORGAN...MURRAY...MUSCOGEE...NEWTON... NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH... PICKENS...PIKE...POLK...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...TALBOT...TALIAFERRO...TAYLOR...TOWNS... TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN... WASHINGTON...WHITE...WHITFIELD...WILKES...WILKINSON. WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM EST WEDNESDAY FOR THE FOLLOWING ZONES: CATOOSA...DAWSON...FANNIN...GILMER... LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WHITE...WHITFIELD. && $$ 37/15 ga AREA FORECAST DISCUSSION...UPDATED FOR AVIATION NATIONAL WEATHER SERVICE PEACHTREE CITY GA 540 PM EST TUE JAN 1 2008 .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... STRONG AREA OF HIGH PRESSURE PRESSING SOUTHEASTWARD OUT OF CANADA WILL CONTINUE TO USHER IN STRONG WINDS AND A COLDER AIR MASS THROUGH THURSDAY NIGHT. HENCE...FORECAST WILL REMAIN DRY THROUGH THE PERIOD. AS A RESULT OF HIGH WINDS...ADVISORY TO REMAIN IN EFFECT THROUGH WEDNESDAY...AND HARD FREEZE WARNING TONIGHT FOR TEMPERATURES EXPECTED TO DROP INTO THE TEENS AND 20S OVER THE NORTHERN MOUNTAINS. .LONG TERM /FRIDAY THROUGH TUESDAY/... HIGH SLIDES EAST OF CWA FRIDAY ALLOWING A MODERATION IN HE AIR MASS...HENCE A RISE IN TEMPERATURES. PREVIOUS GFS RUN (06Z) HAD PRECIPITATION IN FORECAST FOR SATURDAY AND SUNDAY. 12Z RUN WAS MUCH WEAKER...BUT SOME MOISTURE STILL SHOWN. MUCH UNCERTAINTY ABOUT PERIOD...SO LEFT SLIGHT CHC OF RAIN IN FORECAST. && .AVIATION... MOISTURE ASSOCIATED WITH THE DEEP UPPER TROF OVER THE EASTERN PART OF THE COUNTRY CONTINUED TO SAG FARTHER SOUTH TUESDAY AFTERNOON...AND COVERED THE TENNESSEE VALLEY LATE IN THE AFTERNOON. WITH CLOUD BASES AT OR ABOVE 5 THOUSAND FEET...THE MOUNTAINS WILL PROBABLY NOT HOLD THE CLOUDS BACK AS UPPER SHORT WAVE SWINGS THROUGH THE BASE OF THE TROF TONIGHT. LOOKING FOR SCATTERED CLOUDS WITH BASES BETWEEN 4 AND 6 THOUSAND FEET...WITH A PERIOD OF BROKEN CLOUDS IN THE KATL AND KAHN AREAS. BOTH THE RUC AND NAM ARE BEING USED TO HELP WITH TIMING. SCATTERED CLOUDS MAY LINGER AFTER THE MAIN UPPER SHORT WAVE PASSES. WIND SPEEDS MAY EBB AT TIMES OVERNIGHT...BUT GRADIENT REMAINS STRONG AND BECOMES EVEN STRONGER TOWARD DAYBREAK. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 25 41 18 44 19 / 0 5 0 5 5 ATLANTA 22 37 19 41 22 / 0 0 0 5 5 BLAIRSVILLE 21 31 15 41 13 / 30 10 0 5 5 CARTERSVILLE 23 35 15 41 16 / 0 0 0 5 5 COLUMBUS 27 42 21 49 22 / 0 0 0 5 5 GAINESVILLE 23 35 17 42 19 / 0 5 0 5 5 MACON 28 44 20 49 20 / 0 0 0 5 5 ROME 22 38 15 45 14 / 0 0 0 5 5 PEACHTREE CITY 21 36 14 44 9 / 0 0 0 5 5 VIDALIA 25 43 17 49 19 / 0 0 0 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM EST WEDNESDAY FOR THE FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BUTTS...CARROLL... CATOOSA...CHATTAHOOCHEE...CHATTOOGA...CHEROKEE...CLARKE... CLAYTON...COBB...COWETA...CRAWFORD...DADE...DAWSON...DEKALB... DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GLASCOCK...GORDON...GREENE...GWINNETT...HALL...HANCOCK... HARALSON...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER... JONES...LAMAR...LUMPKIN...MACON...MADISON...MARION... MERIWETHER...MONROE...MORGAN...MURRAY...MUSCOGEE...NEWTON... NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH... PICKENS...PIKE...POLK...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...TALBOT...TALIAFERRO...TAYLOR...TOWNS... TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN... WASHINGTON...WHITE...WHITFIELD...WILKES...WILKINSON. WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 9 AM EST WEDNESDAY FOR THE FOLLOWING ZONES: CATOOSA...DAWSON...FANNIN...GILMER... LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WHITE...WHITFIELD. && $$ 37/15 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 602 PM EST WED JAN 2 2008 .AVIATION... A BAND OF LAKE EFFECT SNOW SHOWERS WILL TRANSLATE EAST...AND SHOULD MOVE EAST OF THE FWA AND SBN TAF SITES EARLY IN THE FORECAST PERIOD. SUBSEQUENTLY...CONDITIONS SHOULD BECOME VFR TONIGHT AND PERSIST INTO THURSDAY AS WINDS BACK TO THE SOUTHWEST AS A SURFACE HIGH MOVES INTO THE OHIO VALLEY REGION. && .HYDROLOGY... MUCH WARMER WEATHER WILL RETURN THIS WEEKEND ALONG WITH THE CHANCE FOR RAIN. TEMPERATURES WELL INTO THE 40S ARE EXPECTED TO MELT MUCH OF THE SNOW EARLY NEXT WEEK. GIVEN CURRENT SOIL CONDITIONS...SNOW MELT AND EXPECTED RAINFALL...RIVER LEVELS ARE EXPECTED TO RISE SIGNIFICANTLY EARLY NEXT WEEK...WITH RIVER FLOODING LIKELY BY WEDNESDAY. && .PREV DISCUSSION... /ISSUED 447 PM EST WED JAN 2 2008/ SHORT TERM... TRICKY FORECAST ONCE AGAIN WITH THE MAIN CONCERNS BEING THE ONGOING LAKE EFFECT SNOW ACROSS NW PORTIONS OF THE FA AND LOW TEMPS/CLEARING TONIGHT. RUC 13...12Z NAM AND SREF HAVE BEEN HANDLING SHORT TERM/LAKE PROCESSES DECENT FOR THE MOST PART (WITH ADJUSTMENTS TO CURRENT OBS)...SO HAVE TRENDED FORECAST TO THEM. POTENT SHORELINE BAND OVER PORTIONS OF LA PORTE AND BERRIEN COUNTIES WILL CONTINUE TO SHIFT EAST THROUGH THE EVENING...AND WAIN IN THE PROCESS. NAM H925 OMEGA FIELDS CONTINUE TO SUPPORT TRANSITION FROM AN INTENSE SINGLE BAND TO MULTIPLE PARALLEL BANDS AS WINDS SHIFT MORE WESTERLY. GIVEN DECENT UPWARD VERTICAL VELOCITIES CENTERED JUST BELOW THE DENDRITIC GROWTH ZONE/STRONG LL CONVERGENCE IN PLACE INDICATED BY CONVERGENCE WIND SIGNATURE/COLLOCATION OF SFC SYNOPTIC TROUGH NEAR THE SOUTH END OF THE BAND/NAM BUFFER INDICATED LAKE INDUCED CAPE VALUES OF NEARLY 350 J/KG...EXPECT HEAVY TO MODERATE SNOW TO PERSIST THROUGH THE ADVISORY PERIOD. ADVISORY MAY HAVE TO EXTENDED INTO THE EVENING FOR BERRIEN AND ST JOSEPH COUNTIES AS MODELS MAY TO QUICK TO DIMINISH THE SNOW...ESPECIALLY WITH STRONG CONVERGENCE PRESENT PER 30 KNOT WINDS AT MICHIGAN CITY. BUT WITH EXTREMELY DRY MOVING IN UPSTREAM AND LOSS OF LAKE AGGREGATE PROCESSES PER LOSS OF FLOW OFF OF LAKE SUPERIOR...DIMINISHING TREND MAKES SENSE. WILL LET EVENING SHIFT RE-ASSES. CLEARING IS EXPECTED TONIGHT OVER WESTERN PORTIONS OF THE FA WILL ALLOW EXCELLENT RADIATIONAL COOLING AS WINDS DIMINISH. SNOW COVER IN PLACE WILL WILL ALLOW TEMPS TO DROP QUICKLY...WITH SOME AREAS FALLING BELOW ZERO F. HAVE LOWERED TEMPS WELL BELOW MOS TO REFLECT DRY AIR IN PLACE...AND POTENTIAL DROP PER DRY AIR ALOFT. CLOUDS OVER EASTERN PORTIONS OF THE FA MAY ALSO CLEAR AS LAKE PRECESS WILL BE THE SOLE CONTRIBUTION TO THE CLOUD FIELD TONIGHT. HAVE TRIED TO ADJUST CLOUD COVER TO H925 TRENDS...AND REFLECT THIS IN MINS. LOOK FOR CLEAR SKIES TOMORROW WITH COOL TEMPS ONCE AGAIN. HAVE UNDER CUT MOS GAIN DUE TO UPSTREAM TRENDS AND EXPECTED MIXING HEIGHTS. NW PORTIONS OF THE FA MAY SEE THE WARMER TEMPS AS WAA ENSUES AND ALLOWS RAPID THICKNESS INCREASES AND INCREASED LL FLOW. LONG TERM... THURSDAY NIGHT THROUGH WEDNESDAY...THE LONG WAVE TROF WILL BECOME REESTABLISHED OVER THE SOUTHWEST CONUS THIS WEEKEND...WITH AN AMPLIFYING RIDGE DOWNSTREAM OVER THE EASTERN CONUS. SMALLER SHORTWAVE TROFS WILL EJECT EAST OUT OF THE MAIN TROF...BRINGING THE CHANCE FOR PRECIPITATION STARTING SATURDAY. TEMPERATURES WILL GRADUALLY RISE ABOVE NORMAL AS SOUTH TO SOUTHWEST LOW LEVEL WINDS PERSIST. AREAS OF FOG WILL DEVELOP THIS WEEKEND AS LOW LEVEL MOISTURE INCREASES AND MOVES OVER SNOW COVERED AREAS. THE FOG WILL PROBABLY PERSIST TO AT LEAST SOME EXTENT UNTIL THE SNOW MELTS...CONSIDERING DEW POINT TEMPERATURES RISING TO NEAR 40F. HIGHS WILL BE TEMPERED BY SNOW COVER THROUGH THE WEEKEND...ESPECIALLY OVER NORTHERN AREAS WHERE SNOW COVER IS DEEPER AND WILL TAKE LONGER TO MELT. HAVE KEPT A CHANCE FOR RAIN FROM SATURDAY THROUGH TUESDAY AND ADDED A CHANCE FOR RAIN WEDNESDAY GIVEN SHORT WAVE TROFS MIGRATING NORTHEAST INTO THE GREAT LAKES REGION. A MAJOR TROF SHOULD MOVE EAST TUESDAY OR WEDNESDAY...AND BRING THE POTENTIAL FOR MORE RIVER FLOODING AS RUNOFF RAIN WATER COMBINES WITH RECENT SNOWMELT. THE GFS PER COMET/UCAR ENSEMBLE EXPERIMENTAL ANALYSIS CONTINUED TO INDICATE MUCH UNCERTAINTY TUESDAY INTO WEDNESDAY...SO CONFIDENCE IS LOW BY THE MIDDLE OF NEXT WEEK. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR INZ003-004. MI...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ077. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...SKIPPER AVIATION...SKIPPER HYDROLOGY...SKIPPER in AREA FORECAST DISCUSSION...DELAYED NATIONAL WEATHER SERVICE NORTHERN INDIANA 447 PM EST WED JAN 2 2008 .SHORT TERM... TRICKY FORECAST ONCE AGAIN WITH THE MAIN CONCERNS BEING THE ONGOING LAKE EFFECT SNOW ACROSS NW PORTIONS OF THE FA AND LOW TEMPS/CLEARING TONIGHT. RUC 13...12Z NAM AND SREF HAVE BEEN HANDLING SHORT TERM/LAKE PROCESSES DECENT FOR THE MOST PART (WITH ADJUSTMENTS TO CURRENT OBS)...SO HAVE TRENDED FORECAST TO THEM. POTENT SHORELINE BAND OVER PORTIONS OF LA PORTE AND BERRIEN COUNTIES WILL CONTINUE TO SHIFT EAST THROUGH THE EVENING...AND WAIN IN THE PROCESS. NAM H925 OMEGA FIELDS CONTINUE TO SUPPORT TRANSITION FROM AN INTENSE SINGLE BAND TO MULTIPLE PARALLEL BANDS AS WINDS SHIFT MORE WESTERLY. GIVEN DECENT UPWARD VERTICAL VELOCITIES CENTERED JUST BELOW THE DENDRITIC GROWTH ZONE/STRONG LL CONVERGENCE IN PLACE INDICATED BY CONVERGENCE WIND SIGNATURE/COLLOCATION OF SFC SYNOPTIC TROUGH NEAR THE SOUTH END OF THE BAND/NAM BUFFER INDICATED LAKE INDUCED CAPE VALUES OF NEARLY 350 J/KG...EXPECT HEAVY TO MODERATE SNOW TO PERSIST THROUGH THE ADVISORY PERIOD. ADVISORY MAY HAVE TO EXTENDED INTO THE EVENING FOR BERRIEN AND ST JOSEPH COUNTIES AS MODELS MAY TO QUICK TO DIMINISH THE SNOW...ESPECIALLY WITH STRONG CONVERGENCE PRESENT PER 30 KNOT WINDS AT MICHIGAN CITY. BUT WITH EXTREMELY DRY MOVING IN UPSTREAM AND LOSS OF LAKE AGGREGATE PROCESSES PER LOSS OF FLOW OFF OF LAKE SUPERIOR...DIMINISHING TREND MAKES SENSE. WILL LET EVENING SHIFT RE-ASSES. CLEARING IS EXPECTED TONIGHT OVER WESTERN PORTIONS OF THE FA WILL ALLOW EXCELLENT RADIATIONAL COOLING AS WINDS DIMINISH. SNOW COVER IN PLACE WILL WILL ALLOW TEMPS TO DROP QUICKLY...WITH SOME AREAS FALLING BELOW ZERO F. HAVE LOWERED TEMPS WELL BELOW MOS TO REFLECT DRY AIR IN PLACE...AND POTENTIAL DROP PER DRY AIR ALOFT. CLOUDS OVER EASTERN PORTIONS OF THE FA MAY ALSO CLEAR AS LAKE PRECESS WILL BE THE SOLE CONTRIBUTION TO THE CLOUD FIELD TONIGHT. HAVE TRIED TO ADJUST CLOUD COVER TO H925 TRENDS...AND REFLECT THIS IN MINS. LOOK FOR CLEAR SKIES TOMORROW WITH COOL TEMPS ONCE AGAIN. HAVE UNDER CUT MOS GAIN DUE TO UPSTREAM TRENDS AND EXPECTED MIXING HEIGHTS. NW PORTIONS OF THE FA MAY SEE THE WARMER TEMPS AS WAA ENSUES AND ALLOWS RAPID THICKNESS INCREASES AND INCREASED LL FLOW. && .LONG TERM... THURSDAY NIGHT THROUGH WEDNESDAY...THE LONG WAVE TROF WILL BECOME REESTABLISHED OVER THE SOUTHWEST CONUS THIS WEEKEND...WITH AN AMPLIFYING RIDGE DOWNSTREAM OVER THE EASTERN CONUS. SMALLER SHORTWAVE TROFS WILL EJECT EAST OUT OF THE MAIN TROF...BRINGING THE CHANCE FOR PRECIPITATION STARTING SATURDAY. TEMPERATURES WILL GRADUALLY RISE ABOVE NORMAL AS SOUTH TO SOUTHWEST LOW LEVEL WINDS PERSIST. AREAS OF FOG WILL DEVELOP THIS WEEKEND AS LOW LEVEL MOISTURE INCREASES AND MOVES OVER SNOW COVERED AREAS. THE FOG WILL PROBABLY PERSIST TO AT LEAST SOME EXTENT UNTIL THE SNOW MELTS...CONSIDERING DEW POINT TEMPERATURES RISING TO NEAR 40F. HIGHS WILL BE TEMPERED BY SNOW COVER THROUGH THE WEEKEND...ESPECIALLY OVER NORTHERN AREAS WHERE SNOW COVER IS DEEPER AND WILL TAKE LONGER TO MELT. HAVE KEPT A CHANCE FOR RAIN FROM SATURDAY THROUGH TUESDAY AND ADDED A CHANCE FOR RAIN WEDNESDAY GIVEN SHORT WAVE TROFS MIGRATING NORTHEAST INTO THE GREAT LAKES REGION. A MAJOR TROF SHOULD MOVE EAST TUESDAY OR WEDNESDAY...AND BRING THE POTENTIAL FOR MORE RIVER FLOODING AS RUNOFF RAIN WATER COMBINES WITH RECENT SNOWMELT. THE GFS PER COMET/UCAR ENSEMBLE EXPERIMENTAL ANALYSIS CONTINUED TO INDICATE MUCH UNCERTAINTY TUESDAY INTO WEDNESDAY...SO CONFIDENCE IS LOW BY THE MIDDLE OF NEXT WEEK. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR INZ003-004. MI...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ077. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...SKIPPER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1228 PM EST WED JAN 2 2008 .UPDATE... OPTED TO DOWNGRADE LAKE EFFECT WARNING TO ADVISORY. CURRENT SFC ANALYSIS REVEALS AN INTENSE LAKE INDUCED MESO-LOW CENTERED OVER BEH...WITH A NICE CONVERGENT SIGNATURE IN THE SFC WIND FIELD. THIS SYSTEM IS SUPPORTING THE DEVELOPMENT OF INTENSE POCKETS OF HEAVY SNOW MAINLY ALONG THE LEADING EDGE OF THE PRESSURE RISE/FALL COUPLET/WAA ZONE. VISBYS DOWN TO 1/2 MILE HAVE BEEN OBSERVED WITH THIS SYSTEM...AND WOULD NOT BE SURPRISED TO SEE LOWER AREAS. SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR MAY BE POSSIBLE IN THE HEAVIEST CONVECTIVE POCKETS. HOWEVER...THE SNOW SHOWERS ARE TRANSIENT AND WILL NOT LAST LONG AT A GIVEN LOCATION. FARTHER WEST...A MID-LAKE CONVECTIVE BAND WAS EVIDENT IN SAT AND RADAR OBS. THE LEADING EDGE OF THIS SYSTEM IS JUST NOW ENTERING SW BERRIEN AND NORTHERN LA PORTE COUNTIES. MODEL GUIDANCE IS POORLY HANDLING THIS FEATURE WITH POOR LL VERTICAL MOTION PLACEMENT. HAVE OPTED TO USE THE NAM FOR GUIDANCE WITH HELP FROM THE RUC 13...WITH MODIFICATION OF THEIR OUTPUT BASED ON OBS. BUFFER SOUNDINGS ARE PROGGING NEARLY 350 J/KG OF CAPE...SUPPORTING MODERATE LL LIFT. AS THE MESO LOW PROGRESS INLAND...IT WILL QUICKLY WAIN AS HEAT FLUX FROM THE LAKE WILL END. THUS...EXPECTING THE DOMINATE PLAYER TO BECOME THE MID-LAKE BAND THIS AFTERNOON. HOWEVER...THIS FEATURE WILL ALSO UNDERGO DEGRADATION AS INVERSION HEIGHTS BEGIN TO FALL AND DRIER AIR CONTINUES TO ADVECT INTO THE REGION. 925 MODEL OMEGA FIELDS CONFIRM THIS...AS UPWARD MOTION QUICKLY DIMINISHES THIS AFTERNOON AND EVENING. EXPECTING SNOWFALL AMOUNTS TO RANGE FROM 2 TO 4 INCHES IN THE ADVISORY AREA GIVEN TRANSIENT NATURE OF THE BANDS/WAINING TRENDS IN LIFT/LOSS OF MESO LOW/AND PLACEMENT OF VERTICAL MOTION MAX IN RELATION TO THE DENDRIDIC GROWTH ZONE. HIGHEST SNOWFALL AMOUNTS ARE EXPECTED AT THE SOUTH END OF THE MID-LAKE BAND WHERE RESIDENCE TIME WILL BE THE MAIN FACTOR IN ACCUMULATIONS. EXPECT A TRANSITION TO PARALLEL BANDS LATE THIS AFTERNOON AS LL WINDS TURN MORE WESTERLY...DIMINISHING LAKE SNOWS TO FLURRIES LATER THIS EVENING. && .PREV DISCUSSION... /ISSUED 643 AM EST WED JAN 2 2008/ AVIATION (12Z TAFS)... MVFR AND IFR CONDITIONS ARE FOUND ACROSS THE OUTLOOK AREA...WITH CIGS AROUND 1 TO 2K FEET AND SOME RESTRICTION TO VSBY DUE TO BR AND -SN. THIS WILL CONTINUE THROUGH THIS AFTERNOON AND EVENING. WITH INCREASING CHANCES FOR SNOW LATER THIS MORNING INTO THE EVENING. VSBY AS LOW AS 1/2 TO 1SM WILL BE POSSIBLE CLOSER TO THE LAKE AND THE LAKE EFFECT SNOW SHOWERS. SOME CLEARING AND LESSEN OF THE WESTERLY WINDS WILL OCCUR OVERNIGHT. PREV DISCUSSION... /ISSUED 445 AM EST WED JAN 2 2008/ SHORT TERM (TODAY AND TONIGHT)... .STRONG LAKE EFFECT SNOW POSSIBLE TODAY... EVERYTHING IS STARTING WIND DOWN SOME...BUT ONE MORE ACT IS LEFT TO PLAY OUT TODAY...ANOTHER ROUND OF LAKE EFFECT SNOW. HAVE FOLLOWED CLOSE TO THE RUC13 AND NAM12 THROUGH THE PERIOD. EACH CONTINUE TO SHOWS THE STRONG CAA INTO THE REGION...THE HIGHS FOR TODAY WILL NOT BE FAR FROM THE CURRENT TEMPS AS OF THIS WRITING...WITH SOME CLEARING OF SKIES...LIGHTER WIND AND SNOWPACK ACROSS THE REGION OVERNIGHT LOWS WILL BE MUCH MUCH LOWER THAN GUIDANCE...THE RAW NUMBERS FROM THE RUC HAVE MADE THIS ADJUSTMENT AND HAVE LEANED HEAVILY THAT WAY. THE AMOUNT OF CLOUD COVER WILL BE THE BIGGEST PART TO THIS...WHERE NO OR VERY LITTLE CLOUD COVER EXISTS THE TEMPS WILL DROP FAST. SOME BELOW ZERO READINGS LIKELY. BOTH SAT/OBS AND MODEL DATA WOULD SUGGEST THAT ANOTHER STRONG SHOT OF LAKE EFFECT WOULD BE LIKELY LATE THIS MORNING INTO THE AFTERNOON...AND THEN WINDING DOWN THROUGH THE EVENING. HAVE FOLLOWED CLOSE TO THE 925 MB STREAMLINES AND OMEGAS FOR THE BEST AREAS FOR THE HEAVIER BANDS. ADDITIONAL 3 TO 7 INCHES WITH THE LAKE EFFECT WOULD BE LIKELY...OUTSIDE OF THE PREFERRED LAKE EFFECT AREA UP TO ONE INCH WILL BE POSSIBLE TODAY AND MAYBE ANOTHER INCH TONIGHT DEPENDING ON THE EXACT TRAJECTORIES OF THE BANDS. THE BANDS SHOULD SET UP WITH MORE NORTHERLY TRAJECTORIES THROUGH BERRIEN MI AND ST JOE IN COUNTIES LATE THIS MORNING BEFORE STARTING TO DRIFT MORE FROM THE NORTHWEST AND THEN WEST BY LATE TONIGHT BEFORE THE SFC RIDGING AND THE DRIER AIR STARTS TO INFILTRATE TOO DEEP TO SUSTAIN THE LES. IF WINDS DO NOT DROP OFF SUFFICIENTLY...OR THE FORECAST LOWS NOT LOW ENOUGH THEN ANOTHER WIND CHILL ADVISORY MAY BE NEEDED FOR TONIGHT...THE VALUES ARE VERY CLOSE TO LOCAL CRITERIA. LONG TERM (THURSDAY THROUGH TUESDAY)... ON THURSDAY THE CENTER OF THE HIGH PRESSURE WILL BE MOVING OFF TO THE EAST COAST...ENDING ANY LAKE EFFECT SNOW IN OUR AREA. THE HIGH IS GOING TO BE CENTERED OVER THE EAST COAST INTO SATURDAY. THIS WILL KEEP OUR CWA IN A SOUTHWESTERLY TO SOUTHERLY WIND FLOW...WHICH WILL BRING UP MOISTURE FROM THE GULF OF MEXICO. THIS IS EXPECTED TO REACH OUR CWA SATURDAY. THIS FLOW AND MOISTURE IS THEN EXPECTED TO REMAIN INTO THE BEGINNING OF NEXT WEEK. SO HAVE KEPT RAIN CHANCES IN THE FORECAST FOR THIS WEEKEND. I SAY RAIN AS THIS FLOW REGIME WILL ALSO CAUSE WARM AIR ADVECTION INTO OUR CWA. TEMPERATURES WILL BE CLIMBING FROM THURSDAY TO NEXT MONDAY. FROM HIGHS IN THE LOWER 20S ON THURSDAY TO HIGHS IN THE LOWER 50S ON MONDAY. 850MB TEMPERATURES CLIMB TO AROUND 7 DEGREES CELSIUS ON SUNDAY AND AROUND 9 TO 10 DEGREES CELSIUS ON MONDAY. MODELS ARE REALLY DIFFERING ON A LOW PRESSURE SYSTEM NEXT WEEK. THE SCENARIO IS VASTLY DIFFERENT BETWEEN EACH ONE...BUT THE ONE THING THAT THEY CAN ALL AGREE ON IS THAT THE LOW WILL PASS BY TO OUR NORTHWEST...KEEPING US WARM. AT 06Z TUESDAY THE GFS HAS THE LOW OVER NORTHERN WISCONSIN/NORTHEASTERN MINNESOTA AND THE ECMWF HAS THE LOW OVER THE CENTRAL PLAINS. BY 00Z WEDNESDAY THE GFS MOVES THE LOW TO JAMES BAY IN CANADA AND THE ECMWF MOVES THE LOW TO OVER IOWA. WILL NOT BE MAKING ANY CHANGES FOR NEXT WEEK AT THE MOMENT. A COOL DOWN HOWEVER COULD BE IN STORE FOR THE LATER PART OF NEXT WEEK AS GFS 850MB TEMPS ARE SHOWING COLD 850MB TEMPS DROPPING INTO THE CENTRAL U.S. BY 00Z WEDNESDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR INZ003>005. MI...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ077- 078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ043-046. && $$ SHORT TERM/AVIATION...SCHOTT LONG TERM...LOTHAMER UPDATE...CHAMBERLAIN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 1200 PM EST WED JAN 2 2008 .AVIATION...DISCUSSION FOR 18Z TAFS. MVFR CIGS SHOULD IMPACT THE TAF SITES FROM TIME TO TIME TODAY INTO THIS EVENING. FCST SOUNDINGS SUGGEST THAT LOW CLDS WILL ONLY GRADUALLY DIMINISH OVERNIGHT AS THE INVERSION LOWERS AND DRYING/SUBSIDENCE BEGINS TO DOMINATE. EXPECT VFR CONDS LATER TONIGHT THROUGH THU AS THE SFC HIGH PRESSURE AXIS PASSES OVER THE AREA. && .PREV DISCUSSION... MAIN FORECAST CONCERNS WILL BE TEMPERATURES IN THE SHORT TERM AND THE ENDING OF LIGHT SNOW SHOWERS/FLURRIES AS HIGH PRESSURE OVER THE PLAINS BUILDS THIS WAY. WIND CHILLS ADVISORY WILL ALSO BE NEEDED UNTIL MID MORNING. TEMPERATURES MAY FALL TO NEAR ZERO IN LAFAYETTE AREA TOWARDS SUNRISE AND IN THE SINGLE DIGITS IN MOST OTHER AREAS. IN THE SHORT TERM HAVE GONE WITH A BLEND RUC...NAM SURFACE TEMPERATURES AND IN SOME CASES HAVE HAD TO ADJUST THESE DOWN. MOS TEMPERATURES MAY BE OFF 10 DEGREES TOO WARM FOR THIS MORNING AND LOOKING AT TEMPERATURES UPSTREAM THEY PROBABLY HAVE A PRETTY WARM BIAS AT LEAST INTO THURSDAY. WILL CUT 2 TO 4 DEGREES TODAY AND THURSDAY AND ABOUT 5 DEGREES TONIGHT. SOME LAKE EFFECT SNOW SHOWERS/FLURRIES WILL CONTINUE ACROSS OUR NORTHEAST FORECAST AREA TODAY. HOWEVER SUBSIDENCE INCREASING WILL GRADUALLY END PRECIP FROM THE WEST TODAY AND ACROSS ALL AREAS BY TONIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT WITH SYNOPTIC FEATURES. STRONG UPPER TROUGH ACROSS OUR REGION WILL MOVE RAPIDLY EASTWARD AND OFF EAST COAST BY LATE THURSDAY NIGHT. SURFACE HIGH PRESSURE WILL MOVE EAST ACROSS OUR REGION THURSDAY AND ALL MODELS STILL INDICATING A WARMUP BY THE WEEKEND. REST OF FORECAST LOOKS GOOD AND NO CHANGES MADE FROM THE WEEKEND ON. && .IND WATCHES/WARNINGS/ADVISORIES...WIND CHILL ADVISORY ALONG AND NORTH OF A SULLIVAN TO FRANKLIN TO NEW CASTLE LINE UNTIL 9 AM. && $$ AVIATION...CO PUBLIC...JH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 643 AM EST WED JAN 2 2008 .AVIATION (12Z TAFS)... MVFR AND IFR CONDITIONS ARE FOUND ACROSS THE OUTLOOK AREA...WITH CIGS AROUND 1 TO 2K FEET AND SOME RESTRICTION TO VSBY DUE TO BR AND -SN. THIS WILL CONTINUE THROUGH THIS AFTERNOON AND EVENING. WITH INCREASING CHANCES FOR SNOW LATER THIS MORNING INTO THE EVENING. VSBY AS LOW AS 1/2 TO 1SM WILL BE POSSIBLE CLOSER TO THE LAKE AND THE LAKE EFFECT SNOW SHOWERS. SOME CLEARING AND LESSEN OF THE WESTERLY WINDS WILL OCCUR OVERNIGHT. && .PREV DISCUSSION... /ISSUED 445 AM EST WED JAN 2 2008/ SHORT TERM (TODAY AND TONIGHT)... ..STRONG LAKE EFFECT SNOW POSSIBLE TODAY... EVERYTHING IS STARTING WIND DOWN SOME...BUT ONE MORE ACT IS LEFT TO PLAY OUT TODAY...ANOTHER ROUND OF LAKE EFFECT SNOW. HAVE FOLLOWED CLOSE TO THE RUC13 AND NAM12 THROUGH THE PERIOD. EACH CONTINUE TO SHOWS THE STRONG CAA INTO THE REGION...THE HIGHS FOR TODAY WILL NOT BE FAR FROM THE CURRENT TEMPS AS OF THIS WRITING...WITH SOME CLEARING OF SKIES...LIGHTER WIND AND SNOWPACK ACROSS THE REGION OVERNIGHT LOWS WILL BE MUCH MUCH LOWER THAN GUIDANCE...THE RAW NUMBERS FROM THE RUC HAVE MADE THIS ADJUSTMENT AND HAVE LEANED HEAVILY THAT WAY. THE AMOUNT OF CLOUD COVER WILL BE THE BIGGEST PART TO THIS...WHERE NO OR VERY LITTLE CLOUD COVER EXISTS THE TEMPS WILL DROP FAST. SOME BELOW ZERO READINGS LIKELY. BOTH SAT/OBS AND MODEL DATA WOULD SUGGEST THAT ANOTHER STRONG SHOT OF LAKE EFFECT WOULD BE LIKELY LATE THIS MORNING INTO THE AFTERNOON...AND THEN WINDING DOWN THROUGH THE EVENING. HAVE FOLLOWED CLOSE TO THE 925 MB STREAMLINES AND OMEGAS FOR THE BEST AREAS FOR THE HEAVIER BANDS. ADDITIONAL 3 TO 7 INCHES WITH THE LAKE EFFECT WOULD BE LIKELY...OUTSIDE OF THE PREFERRED LAKE EFFECT AREA UP TO ONE INCH WILL BE POSSIBLE TODAY AND MAYBE ANOTHER INCH TONIGHT DEPENDING ON THE EXACT TRAJECTORIES OF THE BANDS. THE BANDS SHOULD SET UP WITH MORE NORTHERLY TRAJECTORIES THROUGH BERRIEN MI AND ST JOE IN COUNTIES LATE THIS MORNING BEFORE STARTING TO DRIFT MORE FROM THE NORTHWEST AND THEN WEST BY LATE TONIGHT BEFORE THE SFC RIDGING AND THE DRIER AIR STARTS TO INFILTRATE TOO DEEP TO SUSTAIN THE LES. IF WINDS DO NOT DROP OFF SUFFICIENTLY...OR THE FORECAST LOWS NOT LOW ENOUGH THEN ANOTHER WIND CHILL ADVISORY MAY BE NEEDED FOR TONIGHT...THE VALUES ARE VERY CLOSE TO LOCAL CRITERIA. LONG TERM (THURSDAY THROUGH TUESDAY)... ON THURSDAY THE CENTER OF THE HIGH PRESSURE WILL BE MOVING OFF TO THE EAST COAST...ENDING ANY LAKE EFFECT SNOW IN OUR AREA. THE HIGH IS GOING TO BE CENTERED OVER THE EAST COAST INTO SATURDAY. THIS WILL KEEP OUR CWA IN A SOUTHWESTERLY TO SOUTHERLY WIND FLOW...WHICH WILL BRING UP MOISTURE FROM THE GULF OF MEXICO. THIS IS EXPECTED TO REACH OUR CWA SATURDAY. THIS FLOW AND MOISTURE IS THEN EXPECTED TO REMAIN INTO THE BEGINNING OF NEXT WEEK. SO HAVE KEPT RAIN CHANCES IN THE FORECAST FOR THIS WEEKEND. I SAY RAIN AS THIS FLOW REGIME WILL ALSO CAUSE WARM AIR ADVECTION INTO OUR CWA. TEMPERATURES WILL BE CLIMBING FROM THURSDAY TO NEXT MONDAY. FROM HIGHS IN THE LOWER 20S ON THURSDAY TO HIGHS IN THE LOWER 50S ON MONDAY. 850MB TEMPERATURES CLIMB TO AROUND 7 DEGREES CELSIUS ON SUNDAY AND AROUND 9 TO 10 DEGREES CELSIUS ON MONDAY. MODELS ARE REALLY DIFFERING ON A LOW PRESSURE SYSTEM NEXT WEEK. THE SCENARIO IS VASTLY DIFFERENT BETWEEN EACH ONE...BUT THE ONE THING THAT THEY CAN ALL AGREE ON IS THAT THE LOW WILL PASS BY TO OUR NORTHWEST...KEEPING US WARM. AT 06Z TUESDAY THE GFS HAS THE LOW OVER NORTHERN WISCONSIN/NORTHEASTERN MINNESOTA AND THE ECMWF HAS THE LOW OVER THE CENTRAL PLAINS. BY 00Z WEDNESDAY THE GFS MOVES THE LOW TO JAMES BAY IN CANADA AND THE ECMWF MOVES THE LOW TO OVER IOWA. WILL NOT BE MAKING ANY CHANGES FOR NEXT WEEK AT THE MOMENT. A COOL DOWN HOWEVER COULD BE IN STORE FOR THE LATER PART OF NEXT WEEK AS GFS 850MB TEMPS ARE SHOWING COLD 850MB TEMPS DROPPING INTO THE CENTRAL U.S. BY 00Z WEDNESDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...SNOW AND BLOWING SNOW ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR INZ006>009-012>017. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR INZ003>005. WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR INZ013-015- 020-022>024-032. MI...SNOW AND BLOWING SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ079-080. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ077- 078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ043-046. && $$ SHORT TERM...SCHOTT LONG TERM...LOTHAMER AVIATION...SCHOTT in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 600 AM EST WED JAN 2 2008 .AVIATION...DISCUSSION FOR 12Z TAFS. MVFR CIGS ARE CURRENTLY OVR ALL SITES BUT KLAF. BASED ON UPSTREAM OBS WOULD EXPECT THEM TO BREAK OVR THE NEXT FEW HOURS. HOWEVER WITH INVERSION NOT LIKELY TO ERODE AS NOT A LOT OF SFC WARMING EXPECTED TODAY NOT SURE HOW CLOUDS WL BE ABLE TO MIX OUT. TIME HTS SHOW MOISTURE STICKING AROUND TIL TONIGHT. THINK BEST COURSE OF ACTION AT THIS TIME IS TO INCLUDE MVFR CIGS FOR TODAY AND SLOW THEIR RISE TO VFR TIL TONIGHT. NOT EXPECTING ANYTHING MORE THAN FLURRIES AT THE SITES IN TERMS OF PRECIP SO WL NOT INCLUDE AND NO VSBY RESTRICTIONS EXPECTED. WIND GUSTS MAY PICK UP AGAIN DURING THE DAY BEFORE EASING OFF TONIGHT. && .PREV DISCUSSION... MAIN FORECAST CONCERNS WILL BE TEMPERATURES IN THE SHORT TERM AND THE ENDING OF LIGHT SNOW SHOWERS/FLURRIES AS HIGH PRESSURE OVER THE PLAINS BUILDS THIS WAY. WIND CHILLS ADVISORY WILL ALSO BE NEEDED UNTIL MID MORING. TEMPERATURES MAY FALL TO NEAR ZERO IN LAFAYETTE AREA TOWARDS SUNRISE AND IN THE SINGLE DIGITS IN MOST OTHER AREAS. IN THE SHORT TERM HAVE GONE WITH A BLEND RUC...NAM SURFACE TEMPERATURES AND IN SOME CASES HAVE HAD TO ADJUST THESE DOWN. MOS TEMPERATURES MAY BE OFF 10 DEGREES TOO WARM FOR THIS MORNING AND LOOKING AT TEMPERATURES UPSTREAM THEY PROBABLY HAVE A PRETTY WARM BIAS AT LEAST INTO THURSDAY. WILL CUT 2 TO 4 DEGREES TODAY AND THURSDAY AND ABOUT 5 DEGREES TONIGHT. SOME LAKE EFFECT SNOW SHOWERS/FLURRIES WILL CONTINUE ACROSS OUR NORTHEAST FORECAST AREA TODAY. HOWEVER SUBSIDENCE INCREASING WILL GRADUALLY END PRECIP FROM THE WEST TODAY AND ACROSS ALL AREAS BY TONIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT WITH SYNOPTIC FEATURES. STRONG UPPER TROUGH ACROSS OUR REGION WILL MOVE RAPIDLY EASTWARD AND OFF EAST COAST BY LATE THURSDAY NIGHT. SURFACE HIGH PRESSURE WILL MOVE EAST ACROSS OUR REGION THURSDAY AND ALL MODELS STILL INDICATING A WARMUP BY THE WEEKEND. REST OF FORECAST LOOKS GOOD AND NO CHANGES MADE FROM THE WEEKEND ON. && .IND WATCHES/WARNINGS/ADVISORIES...WIND CHILL ADVISORY ALONG AND NORTH OF A SULLIVAN TO FRANKLIN TO NEW CASTLE LINE UNTIL 9 AM. && $$ AVIATION...CP PUBLIC...JH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 445 AM EST WED JAN 2 2008 .SHORT TERM (TODAY AND TONIGHT)... ...STRONG LAKE EFFECT SNOW POSSIBLE TODAY... EVERYTHING IS STARTING WIND DOWN SOME...BUT ONE MORE ACT IS LEFT TO PLAY OUT TODAY...ANOTHER ROUND OF LAKE EFFECT SNOW. HAVE FOLLOWED CLOSE TO THE RUC13 AND NAM12 THROUGH THE PERIOD. EACH CONTINUE TO SHOWS THE STRONG CAA INTO THE REGION...THE HIGHS FOR TODAY WILL NOT BE FAR FROM THE CURRENT TEMPS AS OF THIS WRITING...WITH SOME CLEARING OF SKIES...LIGHTER WIND AND SNOWPACK ACROSS THE REGION OVERNIGHT LOWS WILL BE MUCH MUCH LOWER THAN GUIDANCE...THE RAW NUMBERS FROM THE RUC HAVE MADE THIS ADJUSTMENT AND HAVE LEANED HEAVILY THAT WAY. THE AMOUNT OF CLOUD COVER WILL BE THE BIGGEST PART TO THIS...WHERE NO OR VERY LITTLE CLOUD COVER EXISTS THE TEMPS WILL DROP FAST. SOME BELOW ZERO READINGS LIKELY. BOTH SAT/OBS AND MODEL DATA WOULD SUGGEST THAT ANOTHER STRONG SHOT OF LAKE EFFECT WOULD BE LIKELY LATE THIS MORNING INTO THE AFTERNOON...AND THEN WINDING DOWN THROUGH THE EVENING. HAVE FOLLOWED CLOSE TO THE 925 MB STREAMLINES AND OMEGAS FOR THE BEST AREAS FOR THE HEAVIER BANDS. ADDITIONAL 3 TO 7 INCHES WITH THE LAKE EFFECT WOULD BE LIKELY...OUTSIDE OF THE PREFERRED LAKE EFFECT AREA UP TO ONE INCH WILL BE POSSIBLE TODAY AND MAYBE ANOTHER INCH TONIGHT DEPENDING ON THE EXACT TRAJECTORIES OF THE BANDS. THE BANDS SHOULD SET UP WITH MORE NORTHERLY TRAJECTORIES THROUGH BERRIEN MI AND ST JOE IN COUNTIES LATE THIS MORNING BEFORE STARTING TO DRIFT MORE FROM THE NORTHWEST AND THEN WEST BY LATE TONIGHT BEFORE THE SFC RIDGING AND THE DRIER AIR STARTS TO INFILTRATE TOO DEEP TO SUSTAIN THE LES. IF WINDS DO NOT DROP OFF SUFFICIENTLY...OR THE FORECAST LOWS NOT LOW ENOUGH THEN ANOTHER WIND CHILL ADVISORY MAY BE NEEDED FOR TONIGHT...THE VALUES ARE VERY CLOSE TO LOCAL CRITERIA. && .LONG TERM (THURSDAY THROUGH TUESDAY)... ON THURSDAY THE CENTER OF THE HIGH PRESSURE WILL BE MOVING OFF TO THE EAST COAST...ENDING ANY LAKE EFFECT SNOW IN OUR AREA. THE HIGH IS GOING TO BE CENTERED OVER THE EAST COAST INTO SATURDAY. THIS WILL KEEP OUR CWA IN A SOUTHWESTERLY TO SOUTHERLY WIND FLOW...WHICH WILL BRING UP MOISTURE FROM THE GULF OF MEXICO. THIS IS EXPECTED TO REACH OUR CWA SATURDAY. THIS FLOW AND MOISTURE IS THEN EXPECTED TO REMAIN INTO THE BEGINNING OF NEXT WEEK. SO HAVE KEPT RAIN CHANCES IN THE FORECAST FOR THIS WEEKEND. I SAY RAIN AS THIS FLOW REGIME WILL ALSO CAUSE WARM AIR ADVECTION INTO OUR CWA. TEMPERATURES WILL BE CLIMBING FROM THURSDAY TO NEXT MONDAY. FROM HIGHS IN THE LOWER 20S ON THURSDAY TO HIGHS IN THE LOWER 50S ON MONDAY. 850MB TEMPERATURES CLIMB TO AROUND 7 DEGREES CELSIUS ON SUNDAY AND AROUND 9 TO 10 DEGREES CELSIUS ON MONDAY. MODELS ARE REALLY DIFFERING ON A LOW PRESSURE SYSTEM NEXT WEEK. THE SCENARIO IS VASTLY DIFFERENT BETWEEN EACH ONE...BUT THE ONE THING THAT THEY CAN ALL AGREE ON IS THAT THE LOW WILL PASS BY TO OUR NORTHWEST...KEEPING US WARM. AT 06Z TUESDAY THE GFS HAS THE LOW OVER NORTHERN WISCONSIN/NORTHEASTERN MINNESOTA AND THE ECMWF HAS THE LOW OVER THE CENTRAL PLAINS. BY 00Z WEDNESDAY THE GFS MOVES THE LOW TO JAMES BAY IN CANADA AND THE ECMWF MOVES THE LOW TO OVER IOWA. WILL NOT BE MAKING ANY CHANGES FOR NEXT WEEK AT THE MOMENT. A COOL DOWN HOWEVER COULD BE IN STORE FOR THE LATER PART OF NEXT WEEK AS GFS 850MB TEMPS ARE SHOWING COLD 850MB TEMPS DROPPING INTO THE CENTRAL U.S. BY 00Z WEDNESDAY. && .PREV DISCUSSION... /ISSUED 1225 AM EST WED JAN 2 2008/ AVIATION (06Z TAFS)... IFR AND MVFR CONDITIONS DOMINATE THE REGION...LOW CIGS AROUND 1 TO 2K FEET WITH VSBYS DOWN TO 1 TO 3 SM ARE THE NORM. LAKE EFFECT BAND STILL MOVING INTO AND THRU THE REGION...THOUGH HAVE STARTED TO WEAKEN SLIGHTLY AS PER RADAR TRENDS...AND RIFT SLIGHT BACK TO THE WEST. THE LAKE EFFECT SHOW RE STRENGTHEN DURING THE MID MORNING TOWARDS MIDDAY...HAVE LOWERED VSBYS WITH SN OR -SN LIKELY...ESPECIALLY AROUND AND NEAR SBN. AS SFC RIDGE STARTS TO PUSH FURTHER INTO THE REGION LATE IN THE PERIOD...THE SNOWS WILL STOP AND VSBYS WILL START TO JUMP BACK INTO VFR LEVELS...THOUGH THE LOW CIGS MAY REMAIN THROUGH THE END OF THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...SNOW AND BLOWING SNOW ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR INZ006>009-012-013-015>017. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR INZ003>005. WIND CHILL ADVISORY UNTIL 9 AM EST THIS MORNING FOR INZ013-015- 020-022>024-032. MI...SNOW AND BLOWING SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ079-080. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ077- 078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ043-046. && $$ SHORT TERM...SCHOTT LONG TERM...LOTHAMER AVIATION...SCHOTT in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 335 AM EST WED JAN 2 2008 .DISCUSSION... MAIN FORECAST CONCERNS WILL BE TEMPERATURES IN THE SHORT TERM AND THE ENDING OF LIGHT SNOW SHOWERS/FLURRIES AS HIGH PRESSURE OVER THE PLAINS BUILDS THIS WAY. WIND CHILLS ADVISORY WILL ALSO BE NEEDED UNTIL MID MORING. TEMPERATURES MAY FALL TO NEAR ZERO IN LAFAYETTE AREA TOWARDS SUNRISE AND IN THE SINGLE DIGITS IN MOST OTHER AREAS. IN THE SHORT TERM HAVE GONE WITH A BLEND RUC...NAM SURFACE TEMPERATURES AND IN SOME CASES HAVE HAD TO ADJUST THESE DOWN. MOS TEMPERATURES MAY BE OFF 10 DEGREES TOO WARM FOR THIS MORNING AND LOOKING AT TEMPERATURES UPSTREAM THEY PROBABLY HAVE A PRETTY WARM BIAS AT LEAST INTO THURSDAY. WILL CUT 2 TO 4 DEGREES TODAY AND THURSDAY AND ABOUT 5 DEGREES TONIGHT. SOME LAKE EFFECT SNOW SHOWERS/FLURRIES WILL CONTINUE ACROSS OUR NORTHEAST FORECAST AREA TODAY. HOWEVER SUBSIDENCE INCREASING WILL GRADUALLY END PRECIP FROM THE WEST TODAY AND ACROSS ALL AREAS BY TONIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT WITH SYNOPTIC FEATURES. STRONG UPPER TROUGH ACROSS OUR REGION WILL MOVE RAPIDLY EASTWARD AND OFF EAST COAST BY LATE THURSDAY NIGHT. SURFACE HIGH PRESSURE WILL MOVE EAST ACROSS OUR REGION THURSDAY AND ALL MODELS STILL INDICATING A WARMUP BY THE WEEKEND. REST OF FORECAST LOOKS GOOD AND NO CHANGES MADE FROM THE WEEKEND ON. && .AVIATION...DISCUSSION FOR 06Z TAFS SNOW SHOWERS LOOK TO CONTINUE TO DECREASE ACROSS THE TAF SITES IN THE EARLY PART OF THE TAF PD. WILL HAVE TO WATCH LAF FOR POSSIBLE LAKE BANDS...BUT HAVE GONE OPTIMISTIC AND ENDED SNOW THERE BY 09Z. VSBYS MAY STILL GO TO IFR AT LAF EARLY FOR BRIEF PERIODS...BUT EXPECT MVFR OR BETTER VSBYS ELSEWHERE EARLY BEFORE BECOMING VFR BY 09Z. LOW LEVEL MOISTURE WILL REMAIN ACROSS THE TAF SITES THROUGH THE PERIOD...SO CONTINUED MVFR CIGS THROUGH MUCH OF THE DAY...WITH IMPROVEMENT EXPECTED BY EVENING. && .IND WATCHES/WARNINGS/ADVISORIES...WIND CHILL ADVISORY ALONG AND NORTH OF A SULLIVAN TO FRANKLIN TO NEW CASTLE LINE UNTIL 9 AM. && $$ AVIATION...CS PUBLIC...JH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 128 PM EST TUE JAN 1 2008 .UPDATE (2)... ARCTIC STREAM SW OVR CNTRL IL AND CONTD DEEPENING CAA WEDGE WITHIN DEEP CYCLONIC WRAP AROUND MSTR SHIELD AIDING RENEWED WIDESPREAD LK ENHANCEMENT W/EXPANDING/INTENSIFYING RADAR RETURNS IN MOD/HVY SNOW AS TOUCHED UPON IN PRIOR UPDATE. SRN EDGE OF HIGHER OVERNIGHT ACCUMS IN PRIOR WARNING HAD EXPIRED AT 17Z AND SEE MANY REASONS TO REPLACE THAT AREA W/SNOW/BLOWING SNOW ADVSY THROUGH 06Z COMMENSURATE W/TIME HEIGHT DEPICTIONS RETAINING DEEP TROPOSPHERIC MOIST ASCENT UNTIL THEN W/FVRBL DENDRITIC GROWTH ZONE JUXTAPOSED AND IMPLIED ADDNL ACCUMS OF GENERALLY 2 TO 4 INCHES GIVEN 20:1 SNOW RATIO HERE. OUTSIDE THAT...AND WITHIN CONTD WARNING AREA...EXPECT AN ADDNL 3 TO 6 W/LOCALLY HIGHER ALG A BEH...SBN...GSH LINE. STG GRADIENT FLW WILL CONT UNABATED THROUGH TONIGHT AND CONT TO PROMOTE WIDESPREAD BLOWING/DRIFTING ESP AS WATER CONTENT DECREASES. && .UPDATE... FIERCE LAKE ENHANCED SNOWBAND CONTS TO DRIFT EWD...ALG A THREE RIVERS...KENDALLVILLE...GRABIL LINE AND WAS DROPPING A QUICK 1-2 INCHES WITH ITS PASSAGE. UPSTREAM...LL FLW VEERS IN RESPONSE TO STG ARCTIC STREAM SW DIGGING SEWD ACRS ERN IA W/STG CAA NOW SPREADING INLAND ACRS THE AREA AND LK AGGREGATE RESPONSE SEEN IN COMPOSITE LOOPS W/LK SUPERIOR PRECONDITIONING NOTED YIELDING A ENHANCED LK RESPONSE...AUGMENTED W/ADDNL SPRT ALOFT FM ARCTIC WAVE. SEE SOME PROBS W/CURRENT GRIDDED BREAKOUT...NAMELY CURRENT EXTENT OF ONGOING WARNING AREA AND MORESO RELEGATED W/HIGHER LK ENHANCED SNOW POTENTIAL THROUGH THIS AFTN ON TOP OF STG SFC GRADIENT FLW. RUC13 AND 06Z NAM/WRF SOLUTION WHILE PAINTING AN INCREASING DEEP LYR SATURATED ASCENT INVOF OF MID LVL ARCTIC WAVE...ALSO ADAMANT ON STG CURVED LL ASCENT PLUME INLAND W/STG LL MSTR FLUX OF LK MICHIGAN. THIS PRESENTS A TWO-FOLD PROBLEM...MOST NOTABLY W/UNDERDONE SNOWFALL AMOUNTS DOWNSTREAM OF THE LAKE AND SECONDARY PROBLEM W/TIMING EXTENT OF INLAND WARNING AREA. IN THE ABSENCE OF 12Z GUIDANCE...WILL TAKE A MEASURED APPROACH AT THIS POINT AND SCALE SNOW AMOUNTS CONSIDERABLY BASED ON CONSENSUS 925MB PLUME ANALYSIS AND BACKING FLOW TRAJECTORIES. THIS NECESSITATES EXTENDING THE WARNING ACRS ST.JOE/LAGRANGE/NOBLE AND KOSCIUSKO COUNTIES UNTIL 23Z W/POTENTIAL TO EXTEND FURTHER IN TIME AND/OR RESHUFFLE AS SECONDARY LK ENHANCEMENT AREA MATURES THIS AFTN PRIOR TO AFTN ZONE ISSUANCE. REMAINDER OF GRIDS ON TRACK. && .AVIATION (12Z TAFS)... MAIN AVIATION CONCERNS ACROSS THE REGION WILL THE BE LOW CIGS AND VSBYS...ALONG WITH THE STRONG AND GUSTY WINDS THAT WILL DEVELOP TODAY. LIFR TO IFR CONDITIONS WILL BE LIKELY THRU MUCH OF THE DAY...WITH CIGS NEAR 1K FEET AND VSBYS AROUND 1-3SM. THE NW PORTIONS OF THE AREA WILL SEE CONTINUOUS LAKE EFFECT SNOW THROUGH THE PERIOD...SCTD PERIODS OF SNOW ELSEWHERE. && .PREV DISCUSSION... /ISSUED 418 AM EST TUE JAN 1 2008/ SHORT TERM (NEW YEARS DAY AND TONIGHT)... ..HEAVY LAKE EFFECT SNOW POSSIBLE... BACK EDGE OF THE STRONG WINTER SYSTEM IS LEAVING THE FORECAST AREA INTO FAR NORTHERN OHIO/LAKE ERIE EARLY THIS MORNING. DEFORMATION BAND APPEARS TO BE WEAKENING SLIGHTLY AS IT STARTS TO EXIT THE REGION...MOVING ACROSS NW OHIO. LAKE EFFECT/ENHANCED SNOW SHOWERS DEVELOPING AND MOVING INTO NW INDIANA AND ACROSS EXTREME SW MICHIGAN IN THE WAKE OF THE STORM. TEMPS HAVE HOVERED AROUND THE FREEZING MARK OR JUST BELOW FOR MUCH OF THE REGION OVERNIGHT...IT WILL BE SHORT-LIVED AS COLD AIR POISED TO THE NORTHWEST TO DRIVE INTO THE REGION TODAY. WILL FOLLOW CLOSER TO THE NAM12 WITH ITS SOLID TRACK RECORD FOR DEALING WITH LES AND BETTER RESOLUTION...AND HAS INITIALIZED WELL. LOW BECOMES NEARLY STACKED ACROSS LAKE ERIE THIS MORNING...DRIFTING FURTHER INTO THE EASTERN GREAT LAKES THROUGH THE AFTERNOON. UPPER LEVEL TROUGH DROPPING FROM MN/WI THIS AFTERNOON INTO THE REGION LATE THIS AFTERNOON INTO THE EVENING. CAA CONTINUES THRU THE MORNING INTO THE AFTN AND EVEN. H850 TEMPS DROPPING TO CLOSE TO -13 OR -14C BY LATE THIS AFTERNOON/EARLY EVENING. DELTA T/S INCREASE THROUGH THE MORNING AND BECOME FAVORABLE BY LATE MORN/EARLY AFTN FOR MODERATE TO HEAVY LES SNOW. BEFORE THIS TIME DECENT BANDS OFF THE LAKE STILL ASSOCIATED WITH THE DEPARTING SYSTEM WILL BRING PERIODS OF SNOW WELL INLAND FROM THE LAKE. AS MENTIONED ABOVE HAVE LEANED TOWARDS THE NAM12 AND ITS 925 OMEGA/STREAMLINE FIELDS TO LOOK FOR BEST AREA/AMOUNTS FOR LES. SHEAR IS LITTLE IF NOT NON-EXISTENT FOR THE MOST PART. STREAMLINES WOULD SUGGEST THAT A CONNECTION TO LAKE SUPERIOR MAYBE POSSIBLE WHICH COULD ENHANCE THE BAND(S). THIS PATTERN STAYS IN PLACE THRU THE PERIOD...HAVE UPPED POPS IN THE NW FORECAST AREA TO HIGH END CATEGORICAL. ALSO AS THE UPPER LEVEL TROUGH PULLS THROUGH IT MAY HELP ENHANCED THE LIFT AND SNOWFALL AMOUNTS...WHILE BRINGING LIGHT ACCUMS AREAWIDE THROUGH THE END OF THE PERIOD. WINDS WILL CONTINUE TO INCREASE WITH THE STRONG PRESS GRADIENT ACROSS THE REGION SQUEEZED BETWEEN THE DEPARTING LOW AND THE LARGE SFC HIGH (1045MB+) ACROSS THE PLAINS. 925 WINDS HOVER AROUND 30-35KNOTS THRU THE PERIOD AND WILL MIX DOWN WITH SOME MINOR LOSS AT BEST...GUSTS IN THE 35-40 MPH POSSIBLE ESPECIALLY IN THE TONIGHT PERIOD WHERE WINDS SEEM TO NOTCH A BIT HIGHER. BLOWING AND DRIFTING OF SNOW WILL AN SIGNIFICANT ISSUE. TEMPS WILL MOST LIKELY FALL THRU THE DAY...WITH LOWS MAINLY IN THE UPPER TEENS BY LATE TUES NIGHT OR EARLY WED...MAYBE SLIGHTLY WARMER CLOSER TO THE LAKE OR IN THE FAR SOUTHEASTERN PORTIONS OF THE AREA LONG TERM (WEDNESDAY THROUGH MONDAY)... ..SIGNIFICANT WARM UP AHEAD... LONG TERM FORECAST WILL FEATURE A SIGNIFICANT WARM UP LATE THIS WEEKEND INTO EARLY NEXT WEEK AS LARGE SCALE RIDGING OVER THE EASTERN PACIFIC SHIFTS WEST UNDER A DEVELOPING NEGATIVE PNA REGIME. THIS WILL PROMOTE INTENSE TROUGHING OVER THE WESTERN US. MEANWHILE MASSIVE RIDGING WILL DEVELOP OVER THE EASTERN US IN RESPONSE TO ROBUST WAA AND LARGE SCALE BLOCKING OVER THE EASTERN ATLANTIC. ENSEMBLE INDICES CONFIRM A LARGE POSITIVE SPIKE IN THE NAO PER AFOREMENTIONED PROCESSES...WHICH COUPLED WITH A NEGATIVE PNA WILL SPELL A WARM PATTERN FOR THE REGION. MODELS AND ENSEMBLES HAVE BEEN...AND CONTINUE TO ADVERTISE THIS PATTERN SHIFT. IN FACT....BY MONDAY EVENING THE NAEFS PROGS H85 TEMPS AT 2.5 STANDARD DEVIATIONS ABOVE CLIMO...IMPRESSIVE NONE THE LESS. BOTTOM LINE...HAVE CONTINUED TO WARM TEMPS SUNDAY AND BEYOND...WITH 50S NOW IN THE GRIDS BOTH SUNDAY AND MONDAY...STILL BELOW CURRENT PROGS. ON THE FRONT END OF THE PERIOD...HAVE INCREASED POPS WED MORNING PER LAKE EFFECT SNOW POTENTIAL DUE TO FAVORABLE NORTH-SOUTH FETCH/AGGREGATE PRECONDITIONING FROM LAKE SUPERIOR/MODERATE LAKE INDUCED CAPE VALUES OF NEARLY 400 J/KG/AND LOW SHEAR. NAM/WRF 925 OMEGA FIELDS CONFIRM AN INTENSE POSITIVE VERTICAL MOTION COUPLET IN PLACE OVER BERRIEN AND ST. JOSEPH (IN) COUNTIES. LAKE SNOWS ARE EXPECTED TO WAIN AS WINDS SHIFT WESTERLY DECREASING FETCH AND INVERSION HEIGHTS LOWER SIGNIFICANTLY. HAVE RETAINED THIS SHIFT NORTH IN THE GRIDS WITH ALL SIG PRECIP ENDING AFTER MIDNIGHT THU MORNING...SAVE A FEW FLURRIES. THUR AND FRIDAY...LOWS THUR AND FRIDAY MORNING WILL BE TRICKY. THUR LOOKS TO BE THE COLDEST DUE TO FAVORABLE POSITION OF SFC HIGH TO THE SE OF THE FA/CLEAR SKIES AND LIGHT WINDS. HOWEVER...LAKE CLOUDS WILL BE A FACTOR. TRIED TO INCLUDE THIS IN THE GRIDS. FRIDAY LOWS WILL ALSO BE TRICKY AGAIN FOR SLIGHTLY DIFFERENT REASONS. EXPECTING CLEAR SKIES ACROSS THE FA. HOWEVER...WINDS WILL BE A FACTOR...ESPECIALLY IN THE WEST AS THE PRESSURE GRADIENT BEGINS TO INTENSIFY PER HEIGHT RISES. HAVE TRENDED LOW BOTH DAYS. BEST CHANCE FOR SUB ZERO TEMPS LOOKS TO BE THU AM IN CENTRAL PORTIONS OF THE FA WHERE SNOW COVER AND CLEAR SKIES ARE EXPECTED. HIGHS BOTH DAYS WILL BE SLOW TO RECOVER...ESPECIALLY THUR WHEN POOR MIXING PER WEAK FLOW AND SNOW COVER WILL HIGHLY LIMIT TEMPS. FRIDAY SHOULD SEE WARMER HIGHS...BUT WITH AN INCREASING LL INVERSION PER HEIGHT RISES/WAA MIXING WILL BE HIGHLY SUBDUED ONCE AGAIN. SATURDAY...RETAINED SHOWER MENTION WITH WEAK SW PROGGED UNDER WAA REGIME. THINKING FOG WILL BE A CONCERN WITH LL THETA-E ADVECTION INTENSIFYING OVER SNOW COVER. HAVE INCLUDED FOG MENTION THROUGH SATURDAY THROUGH SUNDAY AM. SUNDAY THROUGH MONDAY. IMPRESSIVE WAA COUPED WITH STRONG SOUTHERLY FLOW WILL ALLOW TEMPS TO SOAR. MAIN BAROCLINIC ZONE WILL SHIFT WEST...ALLOWING PRECIP CHANCES TO DO THE SAME. THIS MAY ALSO ALLOW SOME SUN IF LOW STRATUS/MID CLOUD CAN BREAK. HAVE WARMED TEMPS TO THE 50S WITH LOWS IN THE MID 40S. WITH PROGGED CONDITIONS...WOULD NOT BE SURPRISED TO SEE 60S. HOWEVER...GIVEN TIME PERIOD AND COLLAB...WILL NOT MAKE SUCH SWEEPING CHANCES AT THIS TIME. MARINE... STRONG GRADIENT WINDS CLOSING IN ON OR SURPASSING GALES THIS AFTERNOON...LARGE WAVES NEARING 12 TO 16 FEET WILL BE POSSIBLE. WITH THE VERY COLD TEMPS...WAVES AND STRONG WINDS LOCAL METHODS SHOW FREEZING SPRAY LIKELY OVER THE LAKE THRU AT LEAST WEDNESDAY AFTERNOON. HAVE ISSUED FREEZING SPRAY ADVISORY FOR THE PERIOD THIS MORN INTO THE AFTERNOON ON WEDNESDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER STORM WARNING UNTIL 7 AM EST /6 AM CST/ WEDNESDAY FOR INZ003>005-014. WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR INZ006- 008-016. SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ WEDNESDAY FOR INZ007-009-012-013-015-017. MI...WINTER STORM WARNING UNTIL 7 AM EST WEDNESDAY FOR MIZ077-078. WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR MIZ079. WINTER STORM WARNING UNTIL NOON EST TODAY FOR MIZ080>081. OH...NONE. LM...FREEZING SPRAY ADVISORY UNTIL 7 PM EST WEDNESDAY FOR LMZ043-046. GALE WARNING UNTIL 10 AM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM...SCHOTT LONG TERM...CHAMBERLAIN AVIATION/MARINE...SCHOTT UPDATE...HOLSTEN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 906 AM EST TUE JAN 1 2008 .UPDATE... FIERCE LAKE ENHANCED SNOWBAND CONTS TO DRIFT EWD...ALG A THREE RIVERS...KENDALLVILLE...GRABIL LINE AND WAS DROPPING A QUICK 1-2 INCHES WITH ITS PASSAGE. UPSTREAM...LL FLW VEERS IN RESPONSE TO STG ARCTIC STREAM SW DIGGING SEWD ACRS ERN IA W/STG CAA NOW SPREADING INLAND ACRS THE AREA AND LK AGGREGATE RESPONSE SEEN IN COMPOSITE LOOPS W/LK SUPERIOR PRECONDITIONING NOTED YIELDING A ENHANCED LK RESPONSE...AUGMENTED W/ADDNL SPRT ALOFT FM ARCTIC WAVE. SEE SOME PROBS W/CURRENT GRIDDED BREAKOUT...NAMELY CURRENT EXTENT OF ONGOING WARNING AREA AND MORESO RELEGATED W/HIGHER LK ENHANCED SNOW POTENTIAL THROUGH THIS AFTN ON TOP OF STG SFC GRADIENT FLW. RUC13 AND 06Z NAM/WRF SOLUTION WHILE PAINTING AN INCREASING DEEP LYR SATURATED ASCENT INVOF OF MID LVL ARCTIC WAVE...ALSO ADAMANT ON STG CURVED LL ASCENT PLUME INLAND W/STG LL MSTR FLUX OF LK MICHIGAN. THIS PRESENTS A TWO-FOLD PROBLEM...MOST NOTABLY W/UNDERDONE SNOWFALL AMOUNTS DOWNSTREAM OF THE LAKE AND SECONDARY PROBLEM W/TIMING EXTENT OF INLAND WARNING AREA. IN THE ABSENCE OF 12Z GUIDANCE...WILL TAKE A MEASURED APPROACH AT THIS POINT AND SCALE SNOW AMOUNTS CONSIDERABLY BASED ON CONSENSUS 925MB PLUME ANALYSIS AND BACKING FLOW TRAJECTORIES. THIS NECESSITATES EXTENDING THE WARNING ACRS ST.JOE/LAGRANGE/NOBLE AND KOSCIUSKO COUNTIES UNTIL 23Z W/POTENTIAL TO EXTEND FURTHER IN TIME AND/OR RESHUFFLE AS SECONDARY LK ENHANCEMENT AREA MATURES THIS AFTN PRIOR TO AFTN ZONE ISSUANCE. REMAINDER OF GRIDS ON TRACK. && .AVIATION (12Z TAFS)... MAIN AVIATION CONCERNS ACROSS THE REGION WILL THE BE LOW CIGS AND VSBYS...ALONG WITH THE STRONG AND GUSTY WINDS THAT WILL DEVELOP TODAY. LIFR TO IFR CONDITIONS WILL BE LIKELY THRU MUCH OF THE DAY...WITH CIGS NEAR 1K FEET AND VSBYS AROUND 1-3SM. THE NW PORTIONS OF THE AREA WILL SEE CONTINUOUS LAKE EFFECT SNOW THROUGH THE PERIOD...SCTD PERIODS OF SNOW ELSEWHERE. && .PREV DISCUSSION... /ISSUED 418 AM EST TUE JAN 1 2008/ SHORT TERM (NEW YEARS DAY AND TONIGHT)... ..HEAVY LAKE EFFECT SNOW POSSIBLE... BACK EDGE OF THE STRONG WINTER SYSTEM IS LEAVING THE FORECAST AREA INTO FAR NORTHERN OHIO/LAKE ERIE EARLY THIS MORNING. DEFORMATION BAND APPEARS TO BE WEAKENING SLIGHTLY AS IT STARTS TO EXIT THE REGION...MOVING ACROSS NW OHIO. LAKE EFFECT/ENHANCED SNOW SHOWERS DEVELOPING AND MOVING INTO NW INDIANA AND ACROSS EXTREME SW MICHIGAN IN THE WAKE OF THE STORM. TEMPS HAVE HOVERED AROUND THE FREEZING MARK OR JUST BELOW FOR MUCH OF THE REGION OVERNIGHT...IT WILL BE SHORT-LIVED AS COLD AIR POISED TO THE NORTHWEST TO DRIVE INTO THE REGION TODAY. WILL FOLLOW CLOSER TO THE NAM12 WITH ITS SOLID TRACK RECORD FOR DEALING WITH LES AND BETTER RESOLUTION...AND HAS INITIALIZED WELL. LOW BECOMES NEARLY STACKED ACROSS LAKE ERIE THIS MORNING...DRIFTING FURTHER INTO THE EASTERN GREAT LAKES THROUGH THE AFTERNOON. UPPER LEVEL TROUGH DROPPING FROM MN/WI THIS AFTERNOON INTO THE REGION LATE THIS AFTERNOON INTO THE EVENING. CAA CONTINUES THRU THE MORNING INTO THE AFTN AND EVEN. H850 TEMPS DROPPING TO CLOSE TO -13 OR -14C BY LATE THIS AFTERNOON/EARLY EVENING. DELTA T/S INCREASE THROUGH THE MORNING AND BECOME FAVORABLE BY LATE MORN/EARLY AFTN FOR MODERATE TO HEAVY LES SNOW. BEFORE THIS TIME DECENT BANDS OFF THE LAKE STILL ASSOCIATED WITH THE DEPARTING SYSTEM WILL BRING PERIODS OF SNOW WELL INLAND FROM THE LAKE. AS MENTIONED ABOVE HAVE LEANED TOWARDS THE NAM12 AND ITS 925 OMEGA/STREAMLINE FIELDS TO LOOK FOR BEST AREA/AMOUNTS FOR LES. SHEAR IS LITTLE IF NOT NON-EXISTENT FOR THE MOST PART. STREAMLINES WOULD SUGGEST THAT A CONNECTION TO LAKE SUPERIOR MAYBE POSSIBLE WHICH COULD ENHANCE THE BAND(S). THIS PATTERN STAYS IN PLACE THRU THE PERIOD...HAVE UPPED POPS IN THE NW FORECAST AREA TO HIGH END CATEGORICAL. ALSO AS THE UPPER LEVEL TROUGH PULLS THROUGH IT MAY HELP ENHANCED THE LIFT AND SNOWFALL AMOUNTS...WHILE BRINGING LIGHT ACCUMS AREAWIDE THROUGH THE END OF THE PERIOD. WINDS WILL CONTINUE TO INCREASE WITH THE STRONG PRESS GRADIENT ACROSS THE REGION SQUEEZED BETWEEN THE DEPARTING LOW AND THE LARGE SFC HIGH (1045MB+) ACROSS THE PLAINS. 925 WINDS HOVER AROUND 30-35KNOTS THRU THE PERIOD AND WILL MIX DOWN WITH SOME MINOR LOSS AT BEST...GUSTS IN THE 35-40 MPH POSSIBLE ESPECIALLY IN THE TONIGHT PERIOD WHERE WINDS SEEM TO NOTCH A BIT HIGHER. BLOWING AND DRIFTING OF SNOW WILL AN SIGNIFICANT ISSUE. TEMPS WILL MOST LIKELY FALL THRU THE DAY...WITH LOWS MAINLY IN THE UPPER TEENS BY LATE TUES NIGHT OR EARLY WED...MAYBE SLIGHTLY WARMER CLOSER TO THE LAKE OR IN THE FAR SOUTHEASTERN PORTIONS OF THE AREA LONG TERM (WEDNESDAY THROUGH MONDAY)... ..SIGNIFICANT WARM UP AHEAD... LONG TERM FORECAST WILL FEATURE A SIGNIFICANT WARM UP LATE THIS WEEKEND INTO EARLY NEXT WEEK AS LARGE SCALE RIDGING OVER THE EASTERN PACIFIC SHIFTS WEST UNDER A DEVELOPING NEGATIVE PNA REGIME. THIS WILL PROMOTE INTENSE TROUGHING OVER THE WESTERN US. MEANWHILE MASSIVE RIDGING WILL DEVELOP OVER THE EASTERN US IN RESPONSE TO ROBUST WAA AND LARGE SCALE BLOCKING OVER THE EASTERN ATLANTIC. ENSEMBLE INDICES CONFIRM A LARGE POSITIVE SPIKE IN THE NAO PER AFOREMENTIONED PROCESSES...WHICH COUPLED WITH A NEGATIVE PNA WILL SPELL A WARM PATTERN FOR THE REGION. MODELS AND ENSEMBLES HAVE BEEN...AND CONTINUE TO ADVERTISE THIS PATTERN SHIFT. IN FACT....BY MONDAY EVENING THE NAEFS PROGS H85 TEMPS AT 2.5 STANDARD DEVIATIONS ABOVE CLIMO...IMPRESSIVE NONE THE LESS. BOTTOM LINE...HAVE CONTINUED TO WARM TEMPS SUNDAY AND BEYOND...WITH 50S NOW IN THE GRIDS BOTH SUNDAY AND MONDAY...STILL BELOW CURRENT PROGS. ON THE FRONT END OF THE PERIOD...HAVE INCREASED POPS WED MORNING PER LAKE EFFECT SNOW POTENTIAL DUE TO FAVORABLE NORTH-SOUTH FETCH/AGGREGATE PRECONDITIONING FROM LAKE SUPERIOR/MODERATE LAKE INDUCED CAPE VALUES OF NEARLY 400 J/KG/AND LOW SHEAR. NAM/WRF 925 OMEGA FIELDS CONFIRM AN INTENSE POSITIVE VERTICAL MOTION COUPLET IN PLACE OVER BERRIEN AND ST. JOSEPH (IN) COUNTIES. LAKE SNOWS ARE EXPECTED TO WAIN AS WINDS SHIFT WESTERLY DECREASING FETCH AND INVERSION HEIGHTS LOWER SIGNIFICANTLY. HAVE RETAINED THIS SHIFT NORTH IN THE GRIDS WITH ALL SIG PRECIP ENDING AFTER MIDNIGHT THU MORNING...SAVE A FEW FLURRIES. THUR AND FRIDAY...LOWS THUR AND FRIDAY MORNING WILL BE TRICKY. THUR LOOKS TO BE THE COLDEST DUE TO FAVORABLE POSITION OF SFC HIGH TO THE SE OF THE FA/CLEAR SKIES AND LIGHT WINDS. HOWEVER...LAKE CLOUDS WILL BE A FACTOR. TRIED TO INCLUDE THIS IN THE GRIDS. FRIDAY LOWS WILL ALSO BE TRICKY AGAIN FOR SLIGHTLY DIFFERENT REASONS. EXPECTING CLEAR SKIES ACROSS THE FA. HOWEVER...WINDS WILL BE A FACTOR...ESPECIALLY IN THE WEST AS THE PRESSURE GRADIENT BEGINS TO INTENSIFY PER HEIGHT RISES. HAVE TRENDED LOW BOTH DAYS. BEST CHANCE FOR SUB ZERO TEMPS LOOKS TO BE THU AM IN CENTRAL PORTIONS OF THE FA WHERE SNOW COVER AND CLEAR SKIES ARE EXPECTED. HIGHS BOTH DAYS WILL BE SLOW TO RECOVER...ESPECIALLY THUR WHEN POOR MIXING PER WEAK FLOW AND SNOW COVER WILL HIGHLY LIMIT TEMPS. FRIDAY SHOULD SEE WARMER HIGHS...BUT WITH AN INCREASING LL INVERSION PER HEIGHT RISES/WAA MIXING WILL BE HIGHLY SUBDUED ONCE AGAIN. SATURDAY...RETAINED SHOWER MENTION WITH WEAK SW PROGGED UNDER WAA REGIME. THINKING FOG WILL BE A CONCERN WITH LL THETA-E ADVECTION INTENSIFYING OVER SNOW COVER. HAVE INCLUDED FOG MENTION THROUGH SATURDAY THROUGH SUNDAY AM. SUNDAY THROUGH MONDAY. IMPRESSIVE WAA COUPED WITH STRONG SOUTHERLY FLOW WILL ALLOW TEMPS TO SOAR. MAIN BAROCLINIC ZONE WILL SHIFT WEST...ALLOWING PRECIP CHANCES TO DO THE SAME. THIS MAY ALSO ALLOW SOME SUN IF LOW STRATUS/MID CLOUD CAN BREAK. HAVE WARMED TEMPS TO THE 50S WITH LOWS IN THE MID 40S. WITH PROGGED CONDITIONS...WOULD NOT BE SURPRISED TO SEE 60S. HOWEVER...GIVEN TIME PERIOD AND COLLAB...WILL NOT MAKE SUCH SWEEPING CHANCES AT THIS TIME. MARINE... STRONG GRADIENT WINDS CLOSING IN ON OR SURPASSING GALES THIS AFTERNOON...LARGE WAVES NEARING 12 TO 16 FEET WILL BE POSSIBLE. WITH THE VERY COLD TEMPS...WAVES AND STRONG WINDS LOCAL METHODS SHOW FREEZING SPRAY LIKELY OVER THE LAKE THRU AT LEAST WEDNESDAY AFTERNOON. HAVE ISSUED FREEZING SPRAY ADVISORY FOR THE PERIOD THIS MORN INTO THE AFTERNOON ON WEDNESDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER STORM WARNING UNTIL 7 AM EST /6 AM CST/ WEDNESDAY FOR INZ003>005-014. WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR INZ006- 008-016. WINTER STORM WARNING UNTIL NOON EST /11 AM CST/ TODAY FOR INZ007-012-013-015>017. MI...WINTER STORM WARNING UNTIL 7 AM EST WEDNESDAY FOR MIZ077-078. WINTER STORM WARNING UNTIL 6 PM EST THIS AFTERNOON FOR MIZ079. WINTER STORM WARNING UNTIL NOON EST TODAY FOR MIZ080>081. OH...NONE. LM...FREEZING SPRAY ADVISORY UNTIL 7 PM EST WEDNESDAY FOR LMZ043-046. GALE WARNING UNTIL 10 AM EST WEDNESDAY FOR LMZ043-046. && $$ SHORT TERM...SCHOTT LONG TERM...CHAMBERLAIN AVIATION/MARINE...SCHOTT UPDATE...HOLSTEN in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1159 AM CST TUE JAN 1 2008 .UPDATE... ADDITIONAL OF 18Z TAF DISCUSSION. && .DISCUSSION... MORNING FCST UPDATE WAS MAINLY TO BETTER TARGET SNOW AND BLOWING SNOW AREAS IN ERN SECTIONS. ALTHOUGH VSBYS ARE DROPPING TO LESS THAN A MILE AT GGI/OTM...DID NOT FEEL DURATION WAS SUFFICIENT TO ISSUE HEADLINE. SHRT WV IS CROSSING MS RIVER AND RADAR TRENDS INDICATE THAT ANY ADVY LEVEL CONDITIONS SHOULD END AS FORCING LIFTS OFF TO THE EAST. UPSTREAM SFC OBS AND WEBCAMS DO NOT INDICATE MUCH IN THE WAY OF BLOWING SNOW AFTER SNOW ENDS. ALSO LOWERED TEMPS/DEWPOINTS TO FIT CURRENT CONDITIONS. 12Z RUC AND LATEST GFS LAMP GUIDANCE FITS REALITY BEST AND SUPPORTS THINKING OF STEADY OR SLOWING FALLING TEMPS THROUGH THE AFTERNOON. NO WIND CHILL ADVY AS OF YET. AFTERNOON READINGS WILL HOVER AROUND -20 CRITERIA...BUT WILL HOLD OFF UNTIL RE-EXAMINATION OF FCST FOR TONIGHT WHEN IT MAY BE MORE SIGNIFICANT. && .AVIATION...01/18Z MAIN FOCUS OF 18Z TERMINAL SET WAS MAGNITUDE OF VSBY AND CIG RESTRICTIONS. MANY SITES REPORTING IFR VSBYS AND CIGS BUT THIS SEEMS OVERDONE JUDGING FROM VISIBLE SATELLITE IMAGERY AND LOCAL WEBCAMS...ESPECIALLY THE CIGS. WEBCAMS SHOW NO EVIDENCE OF SIGNIFICANT BLOWING SNOW OR STRATUS IN MOST INSTANCES...AND CAN SEE THROUGH TO RIVERS OVER MUCH OF IA IN VISIBLE IMAGERY. ASOS/AWOS LIKELY OVER-REPORTING STRATUS DUE TO BLOWING SNOW AND ELEVATED ICE CRYSTALS. THUS DID NOT INCLUDE ANY MENTION OF CIGS AND KEPT VSBYS LOW END MVFR. GUSTY NWLY WINDS SHOULD CONTINUE INTO THE EVE HOURS...BUT DIMINISH AFTER THAT TIME LESSENING PROBLEMS WITH BLOWING SNOW. MODELS SHOW PLENTY OF LOW LEVEL MOISTURE TONIGHT...BUT DID NOT ADD ANY ADDITIONAL STRATUS FOR NOW WITH LITTLE EVIDENCE UPSTREAM. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ BSS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1001 AM CST TUE JAN 1 2008 .DISCUSSION... MORNING FCST UPDATE WAS MAINLY TO BETTER TARGET SNOW AND BLOWING SNOW AREAS IN ERN SECTIONS. ALTHOUGH VSBYS ARE DROPPING TO LESS THAN A MILE AT GGI/OTM...DID NOT FEEL DURATION WAS SUFFICIENT TO ISSUE HEADLINE. SHRT WV IS CROSSING MS RIVER AND RADAR TRENDS INDICATE THAT ANY ADVY LEVEL CONDITIONS SHOULD END AS FORCING LIFTS OFF TO THE EAST. UPSTREAM SFC OBS AND WEBCAMS DO NOT INDICATE MUCH IN THE WAY OF BLOWING SNOW AFTER SNOW ENDS. ALSO LOWERED TEMPS/DEWPOINTS TO FIT CURRENT CONDITIONS. 12Z RUC AND LATEST GFS LAMP GUIDANCE FITS REALITY BEST AND SUPPORTS THINKING OF STEADY OR SLOWING FALLING TEMPS THROUGH THE AFTERNOON. NO WIND CHILL ADVY AS OF YET. AFTERNOON READINGS WILL HOVER AROUND -20 CRITERIA...BUT WILL HOLD OFF UNTIL RE-EXAMINATION OF FCST FOR TONIGHT WHEN IT MAY BE MORE SIGNIFICANT. && .AVIATION...01/12Z UPDATE MAIN FORECAST ISSUES CONTINUE TO BE CEILINGS AND SNOW SHOWERS. THE CEILINGS WILL REMAIN LOW OVER THE NORTHERN AND EASTERN SECTIONS THROUGH MIDDAY WHEN STRONG H500 LOW BEGINS TO EXIT THE AREA TO THE EAST. BREAKS IN THE CLOUD DECK AND VARIABLE CIGS DOT THE REGION EARLY TODAY AND WILL SEE THAT FROM TIME TO TIME THROUGH THE MORNING HOURS. SNOW SHOWERS WILL CONTINUE FOR THE MORNING AS BROADER SCALE FORCING MOVES OVER AREA BETWEEN THROUGH 15Z...WITH BEST FORCING NORTHEAST AND EAST SITES. SHOULD SEE FAIRLY STEADY LIGHT SNOW WITH PERIODS OF VSBY IN IFR RANGE AT KOTM. DEEPER RH WANES AFT 12Z...BUT FLURRIES AND SOME BLSN WILL LIKELY PERSIST THROUGH MUCH OF THE DAY. BLSN WILL ALSO BE AN ISSUE AS WINDS PICK UP AFT 12Z TUES...GUSTING IN EXCESS OF 30KT...ESPECIALLY AT KOTM WHERE FRESH SNOW FELL YESTERDAY. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ REV/BSS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1038 PM MST MON DEC 31 2007 .AVIATION...BAND OF LOWER CLOUDS AND FLURRIES HAS REACHED KIML. HAVE PLACED MVFR CIGS/VSBYS AT KMCK THROUGH 09Z BASED ON TIMING THE ADVECTION OF THESE FEATURES. VFR CONDITIONS WILL CONTINUE AT KGLD. && .PREV DISCUSSION...16Z WATER VAPOR IMAGERY/RUC ANALYSIS INDICATED LONGWAVE TROUGH ACROSS MUCH OF THE CONUS...WITH RIDGING JUST OFF THE WEST COAST. 12Z RAOB DATA INDICATED A FEW 150KT JET STREAKS EMBEDDED IN THE FLOW AT H3 WITH ONE LOCATED ACROSS SOUTHERN COLORADO AND ANOTHER ALONG THE EAST COAST. STRONG GRADIENT AT H7 WAS NOTED WITH -15C OBSERVED AT KDDC AND -6C AT KLMN...WHICH LINED UP FAIRLY WELL WITH AREA OF CLOUDS THIS MORNING. AT THE SURFACE...COLD FRONT WAS WELL TO THE SOUTH OF THE CWA AND WAS LOCATED ACROSS CENTRAL TEXAS. OVERALL MODELS INITIALIZED WELL ACROSS THE AREA AND DIFFERENCES WITH LARGE SCALE FEATURES APPEAR MINIMAL BETWEEN THE OPERATIONAL MODELS AT THIS TIME. TONIGHT...FIRST CONCERN FOR THE PERIOD WILL BE POTENTIAL...IF ANY...FOR SNOW SHOWERS TO DEVELOP LATE THIS AFTERNOON INTO THE EVENING. KLBF SOUNDINGS SHOW FAIRLY STEEP LAPSE RATES OVER A GOOD DEPTH OF THE SOUNDING...WITH THETA-E LAPSE RATES BETWEEN H6 AND H5 AROUND 0. GFS SHIFTS THIS POCKET OF POTENTIAL INSTABILITY TO THE SOUTH ACROSS NORTHERN FRINGE OF COUNTIES. IT IS INTERESTING THAT LAPSE RATES ARE STEEP ENOUGH THAT WARMING THE SURFACE TO THE LOWER 30S WOULD BEGIN TO SUPPORT SFC BASED CONVECTION...ALTHOUGH IT WOULD BE VERY WEAK. ALTHOUGH STABILITY PROFILES LOOK FAVORABLE...FORCING APPEARS ABSENT AS SHORT WAVE TROUGH THAT IS CURRENTLY DROPPING THROUGH THE DAKOTAS WILL NOT BEGIN TO IMPACT THE AREA UNTIL AROUND 06Z AND MUCH OF THE FORCING FOR ASCENT WILL BE TO THE NORTH AND EAST. PLAN TO MONITOR TRENDS THIS AFTERNOON BEFORE MAKING ANY FINAL CALL ON PRECIP POTENTIAL. OTHER CONCERN FOR TONIGHT WILL BE WIND/TEMPS AND RESULTING WIND CHILLS. AS MENTIONED BEFORE...STABILITY AHEAD OF THE NEXT TROUGH IS FAIRLY LOW AND SHOULD SEE A DECENT SURFACE RESPONSE AS TROUGH APPROACHES. CONSENSUS OF RUC/NAM/GFS ALL KEEP WINDS UP THROUGH THE NIGHT AS PRESSURE GRADIENT TIGHTENS. WINDS STAYING UP ALL NIGHT MAY ALSO BE WHAT LIMITS WIND CHILL POTENTIAL AS WELL. WEST NORTHWESTERLY WINDS WILL KEEP LOWER BOUNDARY LAYER MIXED SOMEWHAT PREVENTING STRONG DECOUPLING. WIND DIRECTION WILL BE OFF THE SNOWPACK WHICH MAY OFFSET THINGS...BUT ALL IN ALL EXPECT A SIMILAR DIURNAL SWING TO LAST NIGHT. CURRENT MIN TEMP THOUGHTS SEE THE WESTERN HALF OF COLORADO COUNTIES GET TO -13 TO -17 WIND CHILLS...MAINLY ACROSS THE WESTERN HALF OF EASTERN COLORADO COUNTIES. ALTHOUGH THINGS ARE MARGINAL...THINK A SHORT WIND CHILL ADVISORY FOR THE MORNING IS IN ORDER. NEW YEARS DAY/EVENING...SHORT WAVE TROUGH WILL CONTINUE TO THE SOUTH AND EAST OF THE AREA DURING THE MORNING HOURS AS LARGE SCALE RIDGING AND SUBSIDENCE MOVES INTO THE AREA. MAIN CONCERN FOR THIS PERIOD WILL BE WINDS THROUGH THE EARLY AFTERNOON. CWA...ESPECIALLY EASTERN CWA WILL HAVE STRONG HEIGHT/TEMP GRADIENT BETWEEN BUILDING RIDGE AND DEPARTING TROUGH...RESULTING IN AN AXIS STRONG WINDS ALOFT ACROSS THE AREA. MODELS DIFFER IN THE ACTUAL STRENGTH OF THE WINDS WITH NAM THE WEAKEST...GFS THE STRONGEST AND RUC IN THE MIDDLE. WOULD TEND TO FAVOR THE GFS AS IT HAS SEEMED TO PERFORM WELL LATELY SO WILL LEAN MORE IN THIS DIRECTION. GFS BUFR SOUNDINGS...ESPECIALLY IN THE EAST SHOW VERY WEAK SFC BASED INVERSION IN PLACE DURING THE MORNING DUE TO DEEP CAA BEHIND SHORTWAVE TROUGH...AND SUPPORT GUSTS AROUND 40KTS AND POSSIBLY SUSTAINED WINDS APPROACHING 28-30KTS AROUND 18Z. SINCE OTHER MODELS ARE NOT AS AGGRESSIVE WITH THE WINDS...WILL HEDGE BACK A BIT FROM THE GFS AND NOT ISSUE ANY KIND OF WIND ADVISORY BUT WILL HAVE GRIDS NEARING ADVISORY VALUES IN THE EARLY AFTERNOON. SREF/NAM/GFS ALL CONTINUE TO SHOW A SHARP GRADIENT IN MAX TEMPS ACROSS THE CWA...WITH COOLEST TEMPS ACTUALLY IN THE WARMER AIR MASS. GFS/NAM SOUNDINGS SUGGEST THAT WARMING ALOFT MAY BE TOO STRONG OUT WEST...PREVENTING MUCH OF A DEEPLY MIXED BOUNDARY LAYER TO DEVELOP. WITH REMAINING SNOW COVER THERE THAT MAY NOT BE UNREASONABLE...BUT WITH CHANGING AIRMASSES BUMPED UP TEMPS A BIT IN THE WEST. OUT EAST...DEEPLY MIXED BOUNDARY LAYER SHOULD OFFSET COLDER TEMPS ALOFT AND THINK MAX TEMPS TOMORROW SHOULD ONLY BE A FEW DEGREES COLDER THAN TODAY. OVERNIGHT LOWS WILL ONCE AGAIN BE ON THE DIFFICULT SIDE AS MODELS A BIT MORE AGGRESSIVE IN BRINGING IN THE WARMER AIR WITH AMPLIFYING RIDGE. THINK THAT CONDITIONS WILL BE PRETTY OPTIMAL FOR COOLING...BUT AM UNSURE ON THE IMPACT THE WARMER AIR ALOFT WILL HAVE. KEPT THE GENERAL IDEA OF PREVIOUS FORECAST BUT WARMED TEMPS SLIGHTLY. WED-THUR...LARGE RIDGE WILL CONTINUE TO BUILD INTO THE AREA LEADING TO CONTINUED WARMING AND SUBSIDENCE ACROSS THE REGION. WEAK SHORT WAVE TROUGH SLIDES ALONG THE PERIPHERY OF THE RIDGE ON THURSDAY WHICH SHOULD BRING LITTLE MORE THAN INCREASING CLOUDS ACROSS THE AREA...AS POINT SOUNDINGS INDICATE A VERY STRONG AND DRY SUBSIDENCE INVERSION ACROSS THE REGION. WILL CONTINUE THE WARMING TREND THROUGH THE PERIOD...TEMPERED SOMEWHAT BY UNCERTAINTY OF SNOWCOVER IMPACTS. .EXTENDED (FRIDAY-MONDAY)...EC AND OPERATIONAL GFS IN GENERAL AGREEMENT ON THE MEAN FLOW PATTERN DURING THE EXTENDED PERIOD. THERE ARE SLIGHT DIFFERENCES BETWEEN THEM IN TERMS OF STRENGTH AND TIMING OF SEVERAL SHORTWAVE TROUGHS SET TO MOVE THROUGH THE CWA DURING THE EXTENDED. WILL GO WITH A BLEND OF THE TWO FOR THIS FORECAST PACKAGE. FLOW BECOMES MORE ZONAL ON FRIDAY AS A LONGWAVE TROUGH STARTS TO AMPLIFY OVER THE WESTERN CONUS. WITH DRY SOUTHWESTERLY FLOW AT THE SURFACE AND ALOFT AND H85 TEMPS APPROACHING +10C...FRIDAY MAX TEMPS IN THE LOW TO MID 50S SEEM REASONABLE. HAVE SLIGHTLY LOWER TEMPS GOING OVER THE COLORADO COUNTIES AS I FEEL FAIRLY CERTAIN THERE WILL BE ENOUGH RESIDUAL SNOWPACK TO HOLD TEMPS DOWN A FEW DEGREES THERE. FIRST IN THE SERIES OF SHORTWAVE TROUGHS WILL PUSH THROUGH THE AREA LATE SATURDAY BUT SHOULD BRING LITTLE MORE THAN A CHANGE IN WIND DIRECTION AND SLIGHTLY COOLER TEMPS FOR SUNDAY. GFS IS BRINGING THE SECOND ONE IN FOR SUNDAY NIGHT/MONDAY MORNING BUT FEEL IT MAY BE A LITTLE TOO PROGRESSIVE. WENT WITH THE SLOWER EC SOLUTION KEEPING PRECIP OUT OF THE GRIDS FOR NOW. FOR MONDAY...CURSORY GLANCE AT THE 12Z GFS SHOWS A POTENTIAL WINTER STORM FOR THE AREA. 295K ISENTROPIC SURFACE SHOWING STRONG UPGLIDE AND ADVECTION OF 6-8 G/KG MIXING RATIOS. THIS IS MORE IN LINE IN TERMS OF TIMING WITH THE 00Z/31 EC WHICH SHOWS A SIMILAR SOLUTION BUT KEEPS BEST FORCING...AND THEREFORE PRECIP...JUST TO THE NORTHWEST OF THE CWA. WILL NEED TO MONITOR THIS AND POSSIBLY INTRODUCE PRECIP IN THE NEAR FUTURE IF THE MODELS COME INTO CONSENSUS. REGARDLESS OF PRECIP...MONDAY MAX TEMPS WILL BE MUCH COOLER WITH H85 TEMPS OF AROUND -3 TO -5C. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...WIND CHILL ADVISORY FROM 3 AM TO 9 AM MST TUESDAY FOR COZ090>092. && $$ MENTZER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1230 AM EST WED JAN 2 2008 .UPDATE... SNOW SHOWERS CONTINUE ACROSS MUCH OF SOUTHERN INDIANA AND CENTRAL KENTUCKY WITH VISIBILITIES IN HEAVIER SHOWERS DIPPING BELOW ONE MILE AT TIMES...ESPECIALLY WHEN SNOW FALLING COMBINES WITH ONGOING GUSTY NORTHWEST WINDS. THOUGH PRECIPITATION AMOUNTS HAVE BEEN UNDER 0.05 INCHES AND SNOW ACCUMULATIONS HAVE BEEN ON THE LIGHT SIDE (GENERALLY 1/2 INCH OR LESS)...SNOW AND BLOWING SNOW CONTINUES TO CAUSE ICY TRAVEL CONDITIONS...WITH MANY LOCATIONS ACROSS THE EASTERN ZONES REPORTING ACCIDENTS DUE TO ICE ON ROADWAYS. CALLS TO LAW ENFORCEMENT IN LOCATIONS WEST AND NORTHWEST OF LOUISVILLE INDICATED THAT CONDITIONS DUE TO SNOW OR ICY ROADS ARE CAUSING PROBLEMS AT THIS TIME...ESPECIALLY ACROSS PARTS OF DUBOIS COUNTY INDIANA AND WEST CENTRAL KENTUCKY. WILL BE EXPANDING THE SNOW ADVISORY TO INCLUDE THE REMAINING LMK INDIANA COUNTIES AND SEVERAL ADDITIONAL KENTUCKY COUNTIES INCLUDING LARUE COUNTY WEST/NORTHWEST TO HANCOCK COUNTY AND POINTS NORTH.. WILL KEEP TIMING OF ADVISORY WITH REMAINING ZONES AND HAVE ENDING TIME AT 7AM EST/6AM CST. THE SNOW SHOWERS ARE CONVECTIVE IN NATURE...AND ARE DEVELOPING ALONG AN AREA OF VERY STEEP LOW LEVEL LAPSE RATES THAT THE MODELS ARE INDICATING IS IN PLACE FROM EXTREME EASTERN ILLINOIS SOUTHWEST THROUGH SOUTHERN INDIANA AND CENTRAL KENTUCKY. THESE HIT OR MISS ON AGAIN/OFF AGAIN SHOWERS WILL CONTINUE AT LEAST UNTIL THIS AREA OF INSTABILITY MOVES OFF TO THE SOUTH WHICH WILL GRADUALLY OCCUR IN THE NEXT 3 TO 6 HOURS ACROSS THE NORTHWESTERN ZONES AND IN 6 TO 9 HOURS IN THE EASTERN ZONES. LITTLE ADDITIONAL MOISTURE CONTENT WILL FALL WITH THESE SNOW SHOWERS...BUT AN ADDITIONAL .5 OR MORE WILL BE POSSIBLE...WITH SOME HIGHER ADDITIONAL ACCUMULATIONS LIKELY THE FURTHER YOU GO EAST OVERNIGHT AS SNOW WILL CONTINUE THERE MUCH LONGER THAN IN THE WEST. WILL BE ISSUING UPDATED WSW AND OTHER PRODUCTS SHORTLY. .SHORT TERM (TONIGHT AND WEDNESDAY)... MAIN CONCERNS ARE ARCTIC COLD AIR SETTLING ACROSS THE REGION TONIGHT AND TUESDAY. OF EQUAL CONCERN IS THE THREAT OF SNOW SHOWERS TONIGHT. THE LAST RUC AND NAM CONTINUED TO INDICATE THAT THE SECOND SHORT WAVE THAT IS BRINGING THE REALLY COLD AIR TO OUR REGION WILL MOVE ACROSS NORTH CENTRAL AND EAST KENTUCKY OVERNIGHT. THEN TO... THERE ARE SOME INDICATIONS OF LAKE MICHIGAN LOW LEVEL RH FEEDING INTO THE BACK SIDE OF THIS TROUGH. SO SNOW SHOWER ACTIVITY SHOULD INCREASE FOR A TIME TONIGHT. SO WE ARE GOING TO CONTINUE TO GO WITH THE PREVIOUS FCST TRENDS AS REGARDS THE ISSUANCE OF A WEATHER ADVISORY FOR SNOW ACROSS THE NORTHEASTERN HALF OF OUR REGION. POSSIBLE SNOW ACCUMULATIONS FROM AROUND ONE INCH ACROSS CENTRAL SECTIONS OF OUR AREA INCLUDING SDF AND 1 TO 2 INCHES OF SNOW EAST CENTRAL SECTIONS INCLUDING LEXINGTON. THE PREVIOUS DISCUSSION DEFINED THIS SCENARIO QUITE WELL: "1 TO 2 INCHES NEAR LEXINGTON AND COUNTIES SURROUNDING. FROM THIS AREA WEST TO WASHINGTON COUNTY INDIANA...LOUISVILLE SOUTH TO CLINTON WILL GO AROUND AN INCH AND ISSUE A SNOW ADVISORY WITH THIS BEING THE FIRST SIGNIFICANT SNOW OF THE SEASON AND WITH COLD TEMPERATURES AND A WORK DAY HAVING A BIGGER IMPACT ON TRAVEL.". HOWEVER...SINCE THE SNOW SHOWERS ARE ALREADY DEVELOPING ACROSS A GOOD PORTION OF OUR FA...WE WILL START THE ADVISORY AT 4 PM INSTEAD OF 7 PM. GUSTY WINDS A BIT OF A PROBLEM TOO BUT SHOULD DIMINISH INTO THE 15 TO 25 MPH RANGE AND NOT BE A MAJOR PROBLEM. MAX AND MIN TEMP TRENDS IN LINE WITH THE CURRENT FCST. .LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY)... AN EMPHATIC PATTERN CHANGE WILL BEGIN THURSDAY. BY THE WEEKEND...MOIST SOUTHWEST WINDS WILL BRING UNSEASONABLY WARM TEMPERATURES AND INCREASED MOISTURE ALL THE WAY FROM THE WESTERN GULF TO THE GREAT LAKES. WEDNESDAY NIGHT THROUGH FRIDAY... A VERY DEEP AND COLD FULL LATITUDE PROGRESSIVE TROUGH WILL TRANSLATE FROM THE SOUTHEAST COAST TO WELL OUT IN THE ATLANTIC. 500MB HEIGHTS WILL RISE DRAMATICALLY AS ZONAL FLOW ACROSS THE ROCKIES WILL START TO FLOOD THE EAST HALF OF THE COUNTRY WITH MILDER PACIFIC AIR. AT THE SURFACE...MASSIVE ARCTIC HIGH PRESSURE OVER MISSOURI LATE WEDNESDAY (1045MB) WILL SLIDE EAST ACROSS THE TENNESSEE VALLEY EARLY FRIDAY AND PARK ITSELF OVER THE SOUTHEAST COAST BY EARLY SATURDAY. NORTHWEST WINDS WILL BECOME LIGHT LATE WEDNESDAY AND SWITCH TO THE SOUTH BY EARLY FRIDAY. LINGERING LOW CLOUDS WILL EXIT THE BLUEGRASS REGION EARLY THURSDAY AND EXPECT MOSTLY CLEAR SKIES THURSDAY AND FRIDAY. AFTER A COLD START THURSDAY MORNING...TEMPERATURES WILL SLOWLY MODERATE. BY FRIDAY...HIGHS SHOULD REBOUND TO SEASONAL NORMS. SATURDAY THROUGH TUESDAY... RELATIVELY HIGH CONFIDENCE IN THE BROAD LONGWAVE UPPER AIR PATTERN THIS PERIOD WITH GOOD AGREEMENT BETWEEN THE ECMWF...THE OPERATIONAL GFS AND ITS ENSEMBLES. A SERIES OF STORMS WILL MOVE INTO THE WESTERN STATES AND WILL EVENTUALLY CARVE A DEEP LONG-LIVED TROUGH ACROSS THE ROCKIES BY MONDAY. ZONAL FLOW ACROSS THE EAST AND THE LOWER OHIO VALLEY WILL BE REPLACED BY A RIDGE MONDAY IN RESPONSE TO THE DEEPENING WESTERN TROUGH. PRESSURE GRADIENT BETWEEN LEE TROUGHING EAST OF THE ROCKIES AND STILL STRONG HIGH PRESSURE OVER THE SOUTHEAST COAST WILL CREATE A BROAD AREA OF PRETTY DECENT SOUTHWEST FLOW THAT WILL REALLY BRING A SURGE OF MILD AIR NORTH ACROSS OUR REGION. THIS GRADIENT SHOULD CONTINUE FOR SEVERAL DAYS AS THE WESTERN TROUGH DEEPENS IN PLACE. ABOVE NORMAL TEMPERATURES WILL ARRIVE SATURDAY...AND SHOULD WARM EVEN FARTHER FOR SUNDAY THROUGH TUESDAY. THIS TIME OF YEAR...WARM AIR ADVECTION IS FREQUENTLY ACCOMPANIED BY EXTENSIVE CLOUDINESS AS MODIFIED GULF MOISTURE CONDENSES AS AIR IS COOLED ON ITS WAY NORTH. INDIVIDUAL DISTURBANCES WILL BE DIFFICULT TO TIME...BUT MOISTURE WILL FIRST ARRIVE ON SATURDAY ACCORDING TO BOTH THE ECMWF AND THE GFS. HAVE NOT CHANGED ONGOING FORECAST OF AT LEAST A CHANCE OF SHOWERS EACH DAY FROM SATURDAY THROUGH TUESDAY. && .AVIATION (06Z TAFS)... CONVECTIVE SNOW SHOWERS TO CONTINUE OVER AT LEAST THE NEXT 6 HOURS WITH MVFR/IFR CEILINGS AND VISIBILITIES LIKELY IN HEAVIER SHOWERS FOR KSDF. STEADIER SNOW WILL MOVE INTO THE BLUEGRASS REGION OVERNIGHT INCLUDING KLEX WITH IFR CONDS THRU THE MORNING. GUSTY WNW WINDS WILL PERSIST TIL LATE IN THE PERIOD. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY IN EFFECT UNTIL 7 AM EST /6 AM CST/ WEDNESDAY FOR KYZ023>025-028>043-045>049-053>057-065>067-077-078-082. IN...SNOW ADVISORY IN EFFECT UNTIL 7 AM EST WEDNESDAY FOR INZ076>079-083-084-089>092. && $$ UPDATE.......MACZKO SHORT TERM...21 LONG TERM....JSD AVIATION.....11 ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 606 PM EST TUE JAN 1 2008 .SHORT TERM (TONIGHT AND WEDNESDAY)... MAIN CONCERNS ARE ARCTIC COLD AIR SETTLING ACROSS THE REGION TONIGHT AND TUESDAY. OF EQUAL CONCERN IS THE THREAT OF SNOW SHOWERS TONIGHT. THE LAST RUC AND NAM CONTINUED TO INDICATE THAT THE SECOND SHORT WAVE THAT IS BRINGING THE REALLY COLD AIR TO OUR REGION WILL MOVE ACROSS NORTH CENTRAL AND EAST KENTUCKY OVERNIGHT. THEN TO... THERE ARE SOME INDICATIONS OF LAKE MICHIGAN LOW LEVEL RH FEEDING INTO THE BACK SIDE OF THIS TROUGH. SO SNOW SHOWER ACTIVITY SHOULD INCREASE FOR A TIME TONIGHT. SO WE ARE GOING TO CONTINUE TO GO WITH THE PREVIOUS FCST TRENDS AS REGARDS THE ISSUANCE OF A WEATHER ADVISORY FOR SNOW ACROSS THE NORTHEASTERN HALF OF OUR REGION. POSSIBLE SNOW ACCUMULATIONS FROM AROUND ONE INCH ACROSS CENTRAL SECTIONS OF OUR AREA INCLUDING SDF AND 1 TO 2 INCHES OF SNOW EAST CENTRAL SECTIONS INCLUDING LEXINGTON. THE PREVIOUS DISCUSSION DEFINED THIS SCENARIO QUITE WELL: "1 TO 2 INCHES NEAR LEXINGTON AND COUNTIES SURROUNDING. FROM THIS AREA WEST TO WASHINGTON COUNTY INDIANA...LOUISVILLE SOUTH TO CLINTON WILL GO AROUND AN INCH AND ISSUE A SNOW ADVISORY WITH THIS BEING THE FIRST SIGNIFICANT SNOW OF THE SEASON AND WITH COLD TEMPERATURES AND A WORK DAY HAVING A BIGGER IMPACT ON TRAVEL.". HOWEVER...SINCE THE SNOW SHOWERS ARE ALREADY DEVELOPING ACROSS A GOOD PORTION OF OUR FA...WE WILL START THE ADVISORY AT 4 PM INSTEAD OF 7 PM. GUSTY WINDS A BIT OF A PROBLEM TOO BUT SHOULD DIMINISH INTO THE 15 TO 25 MPH RANGE AND NOT BE A MAJOR PROBLEM. MAX AND MIN TEMP TRENDS IN LINE WITH THE CURRENT FCST. .LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY)... AN EMPHATIC PATTERN CHANGE WILL BEGIN THURSDAY. BY THE WEEKEND...MOIST SOUTHWEST WINDS WILL BRING UNSEASONABLY WARM TEMPERATURES AND INCREASED MOISTURE ALL THE WAY FROM THE WESTERN GULF TO THE GREAT LAKES. WEDNESDAY NIGHT THROUGH FRIDAY... A VERY DEEP AND COLD FULL LATITUDE PROGRESSIVE TROUGH WILL TRANSLATE FROM THE SOUTHEAST COAST TO WELL OUT IN THE ATLANTIC. 500MB HEIGHTS WILL RISE DRAMATICALLY AS ZONAL FLOW ACROSS THE ROCKIES WILL START TO FLOOD THE EAST HALF OF THE COUNTRY WITH MILDER PACIFIC AIR. AT THE SURFACE...MASSIVE ARCTIC HIGH PRESSURE OVER MISSOURI LATE WEDNESDAY (1045MB) WILL SLIDE EAST ACROSS THE TENNESSEE VALLEY EARLY FRIDAY AND PARK ITSELF OVER THE SOUTHEAST COAST BY EARLY SATURDAY. NORTHWEST WINDS WILL BECOME LIGHT LATE WEDNESDAY AND SWITCH TO THE SOUTH BY EARLY FRIDAY. LINGERING LOW CLOUDS WILL EXIT THE BLUEGRASS REGION EARLY THURSDAY AND EXPECT MOSTLY CLEAR SKIES THURSDAY AND FRIDAY. AFTER A COLD START THURSDAY MORNING...TEMPERATURES WILL SLOWLY MODERATE. BY FRIDAY...HIGHS SHOULD REBOUND TO SEASONAL NORMS. SATURDAY THROUGH TUESDAY... RELATIVELY HIGH CONFIDENCE IN THE BROAD LONGWAVE UPPER AIR PATTERN THIS PERIOD WITH GOOD AGREEMENT BETWEEN THE ECMWF...THE OPERATIONAL GFS AND ITS ENSEMBLES. A SERIES OF STORMS WILL MOVE INTO THE WESTERN STATES AND WILL EVENTUALLY CARVE A DEEP LONG-LIVED TROUGH ACROSS THE ROCKIES BY MONDAY. ZONAL FLOW ACROSS THE EAST AND THE LOWER OHIO VALLEY WILL BE REPLACED BY A RIDGE MONDAY IN RESPONSE TO THE DEEPENING WESTERN TROUGH. PRESSURE GRADIENT BETWEEN LEE TROUGHING EAST OF THE ROCKIES AND STILL STRONG HIGH PRESSURE OVER THE SOUTHEAST COAST WILL CREATE A BROAD AREA OF PRETTY DECENT SOUTHWEST FLOW THAT WILL REALLY BRING A SURGE OF MILD AIR NORTH ACROSS OUR REGION. THIS GRADIENT SHOULD CONTINUE FOR SEVERAL DAYS AS THE WESTERN TROUGH DEEPENS IN PLACE. ABOVE NORMAL TEMPERATURES WILL ARRIVE SATURDAY...AND SHOULD WARM EVEN FARTHER FOR SUNDAY THROUGH TUESDAY. THIS TIME OF YEAR...WARM AIR ADVECTION IS FREQUENTLY ACCOMPANIED BY EXTENSIVE CLOUDINESS AS MODIFIED GULF MOISTURE CONDENSES AS AIR IS COOLED ON ITS WAY NORTH. INDIVIDUAL DISTURBANCES WILL BE DIFFICULT TO TIME...BUT MOISTURE WILL FIRST ARRIVE ON SATURDAY ACCORDING TO BOTH THE ECMWF AND THE GFS. HAVE NOT CHANGED ONGOING FORECAST OF AT LEAST A CHANCE OF SHOWERS EACH DAY FROM SATURDAY THROUGH TUESDAY. && .AVIATION (00Z TAFS)... CONVECTIVE SNOW SHOWERS TO CONTINUE OVER AT LEAST THE NEXT 6 HOURS WITH MVFR/IFR CEILINGS AND VISIBILITIES LIKELY IN HEAVIER SHOWERS. GUSTY WINDS WILL PERSIST AS WELL AND LEAD TO SOME REDUCTION OF VISIBILITIES IN LIGHTER SHOWERS AS WELL. GUSTS OF AROUND 25KTS SHOULD BE ABOUT AS STRONG AS THE WINDS GET ON A REGULAR BASIS...BUT ISOLATED GUSTS TO 30KTS WILL BE POSSIBLE AT LEAST THROUGH 12Z WED. MORE ISOLATED LIGHT SNOW SHOWERS WILL BE POSSIBLE AFTER 12Z WED...THOUGH REDUCTIONS IN VIS SHOULD BE LIMITED. GUSTY WINDS WILL PERSIST THROUGH THE ENTIRE TAF PERIOD. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY IN EFFECT UNTIL 7 AM EST /6 AM CST/ WEDNESDAY FOR KYZ029>043-045>049-054>057-065>067-077-078-082. IN...SNOW ADVISORY IN EFFECT UNTIL 7 AM EST WEDNESDAY FOR INZ077>079-091-092. && SHORT TERM...21 LONG TERM....JSD AVIATION.....MACZKO $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 253 PM EST TUE JAN 1 2008 .SHORT TERM (TONIGHT AND WEDNESDAY):... MAIN CONCERNS ARE ARCTIC COLD AIR SETTLING ACROSS THE REGION TONIGHT AND TUESDAY. OF EQUAL CONCERN IS THE THREAT OF SNOW SHOWERS TONIGHT. THE LAST RUC AND NAM CONTINUED TO INDICATE THAT THE SECOND SHORT WAVE THAT IS BRINGING THE REALLY COLD AIR TO OUR REGION WILL MOVE ACROSS NORTH CENTRAL AND EAST KENTUCKY OVERNIGHT. THEN TO... THERE ARE SOME INDICATIONS OF LAKE MICHIGAN LOW LEVEL RH FEEDING INTO THE BACK SIDE OF THIS TROUGH. SO SNOW SHOWER ACTIVITY SHOULD INCREASE FOR A TIME TONIGHT. SO WE ARE GOING TO CONTINUE TO GO WITH THE PREVIOUS FCST TRENDS AS REGARDS THE ISSUANCE OF A WEATHER ADVISORY FOR SNOW ACROSS THE NORTHEASTERN HALF OF OUR REGION. POSSIBLE SNOW ACCUMULATIONS FROM AROUND ONE INCH ACROSS CENTRAL SECTIONS OF OUR AREA INCLUDING SDF AND 1 TO 2 INCHES OF SNOW EAST CENTRAL SECTIONS INCLUDING LEXINGTON. THE PREVIOUS DISCUSSION DEFINED THIS SCENARIO QUITE WELL: "1 TO 2 INCHES NEAR LEXINGTON AND COUNTIES SURROUNDING. FROM THIS AREA WEST TO WASHINGTON COUNTY INDIANA...LOUISVILLE SOUTH TO CLINTON WILL GO AROUND AN INCH AND ISSUE A SNOW ADVISORY WITH THIS BEING THE FIRST SIGNIFICANT SNOW OF THE SEASON AND WITH COLD TEMPERATURES AND A WORK DAY HAVING A BIGGER IMPACT ON TRAVEL.". HOWEVER...SINCE THE SNOW SHOWERS ARE ALREADY DEVELOPING ACROSS A GOOD PORTION OF OUR FA...WE WILL START THE ADVISORY AT 4 PM INSTEAD OF 7 PM. GUSTY WINDS A BIT OF A PROBLEM TOO BUT SHOULD DIMINISH INTO THE 15 TO 25 MPH RANGE AND NOT BE A MAJOR PROBLEM. MAX AND MIN TEMP TRENDS IN LINE WITH THE CURRENT FCST. && .LONG TERM (WEDNESDAY NIGHT THROUGH TUESDAY)... AN EMPHATIC PATTERN CHANGE WILL BEGIN THURSDAY. BY THE WEEKEND...MOIST SOUTHWEST WINDS WILL BRING UNSEASONABLY WARM TEMPERATURES AND INCREASED MOISTURE ALL THE WAY FROM THE WESTERN GULF TO THE GREAT LAKES. WEDNESDAY NIGHT THROUGH FRIDAY... A VERY DEEP AND COLD FULL LATITUDE PROGRESSIVE TROUGH WILL TRANSLATE FROM THE SOUTHEAST COAST TO WELL OUT IN THE ATLANTIC. 500MB HEIGHTS WILL RISE DRAMATICALLY AS ZONAL FLOW ACROSS THE ROCKIES WILL START TO FLOOD THE EAST HALF OF THE COUNTRY WITH MILDER PACIFIC AIR. AT THE SURFACE...MASSIVE ARCTIC HIGH PRESSURE OVER MISSOURI LATE WEDNESDAY (1045MB) WILL SLIDE EAST ACROSS THE TENNESSEE VALLEY EARLY FRIDAY AND PARK ITSELF OVER THE SOUTHEAST COAST BY EARLY SATURDAY. NORTHWEST WINDS WILL BECOME LIGHT LATE WEDNESDAY AND SWITCH TO THE SOUTH BY EARLY FRIDAY. LINGERING LOW CLOUDS WILL EXIT THE BLUEGRASS REGION EARLY THURSDAY AND EXPECT MOSTLY CLEAR SKIES THURSDAY AND FRIDAY. AFTER A COLD START THURSDAY MORNING...TEMPERATURES WILL SLOWLY MODERATE. BY FRIDAY...HIGHS SHOULD REBOUND TO SEASONAL NORMS. .SATURDAY THROUGH TUESDAY... RELATIVELY HIGH CONFIDENCE IN THE BROAD LONGWAVE UPPER AIR PATTERN THIS PERIOD WITH GOOD AGREEMENT BETWEEN THE ECMWF...THE OPERATIONAL GFS AND ITS ENSEMBLES. A SERIES OF STORMS WILL MOVE INTO THE WESTERN STATES AND WILL EVENTUALLY CARVE A DEEP LONG-LIVED TROUGH ACROSS THE ROCKIES BY MONDAY. ZONAL FLOW ACROSS THE EAST AND THE LOWER OHIO VALLEY WILL BE REPLACED BY A RIDGE MONDAY IN RESPONSE TO THE DEEPENING WESTERN TROUGH. PRESSURE GRADIENT BETWEEN LEE TROUGHING EAST OF THE ROCKIES AND STILL STRONG HIGH PRESSURE OVER THE SOUTHEAST COAST WILL CREATE A BROAD AREA OF PRETTY DECENT SOUTHWEST FLOW THAT WILL REALLY BRING A SURGE OF MILD AIR NORTH ACROSS OUR REGION. THIS GRADIENT SHOULD CONTINUE FOR SEVERAL DAYS AS THE WESTERN TROUGH DEEPENS IN PLACE. ABOVE NORMAL TEMPERATURES WILL ARRIVE SATURDAY...AND SHOULD WARM EVEN FARTHER FOR SUNDAY THROUGH TUESDAY. THIS TIME OF YEAR...WARM AIR ADVECTION IS FREQUENTLY ACCOMPANIED BY EXTENSIVE CLOUDINESS AS MODIFIED GULF MOISTURE CONDENSES AS AIR IS COOLED ON ITS WAY NORTH. INDIVIDUAL DISTURBANCES WILL BE DIFFICULT TO TIME...BUT MOISTURE WILL FIRST ARRIVE ON SATURDAY ACCORDING TO BOTH THE ECMWF AND THE GFS. HAVE NOT CHANGED ONGOING FORECAST OF AT LEAST A CHANCE OF SHOWERS EACH DAY FROM SATURDAY THROUGH TUESDAY. && .AVIATION (18Z TAFS)... COLD AND SOMEWHAT MOIST ARCTIC AIR CONT TO PUSH SEWD ACROSS REGION THIS AFTN AND TONIGHT. COLD 500 MB TROUGH WILL SLIDE ACROSS NERN HALF OF REGION TONIGHT AND BRING INCREASED CHANCES OF SW- OR S- WITH AT LEAST MVFR CIGS AND VSBYS...SOME BRIEF IFR CONDS POSSIBLE TOO FOR A TIME TONIGHT IF THE UPPER LOW DRIFTS CLOSE ENOUGH TO SDF AND LEX TO AUGMENT THE SNOW POTENTIAL A BIT. AT THIS TIME WILL GO WI MVFR CIGS BECMG LOW MVFR CONDS FOR AT LEAST SDF AND LEX WITH SW- ESPY AFT 00Z TONIGHT AND THEN IMP CONDS BY 12 ON WED. WITH STRONG PRESSURE GRADIENT GRADUALLY RELAXING A BIT WITH RELAX THE GUSTS IN TAFS TOO LATER TONIGHT. --21 && .LMK WATCHES/WARNINGS/ADVISORIES... KY...SNOW ADVISORY FROM 4 PM EST /6 PM CST/ THIS EVENING TO 7 AM EST /6 AM CST/ WEDNESDAY FOR KYZ029>043-045>049-054>057-065>067- 077-078-082. IN...SNOW ADVISORY FROM 4 PM THIS EVENING TO 7 AM EST WEDNESDAY FOR INZ077>079-091-092. && SHORT TERM...21 LONG TERM....JSD AVIATION.....21 $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 937 AM EST WED JAN 2 2008 .SYNOPSIS... LOW PRESSURE WILL CONTINUE TO MOVE AWAY FROM THE REGION TODAY ALLOWING COLD ARCTIC AIR TO FOLLOW THIS SYSTEM ON BRISK NORTHERLY WINDS LATER TODAY AND TONIGHT. AS HIGH PRESSURE BECOMES ESTABLISHED OVER THE SOUTHEASTERN STATES...THE RETURN FLOW WILL RESULT IN A GRADUAL WARMING TREND FOR THE REGION BEGINNING OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SNOW HAS GREATLY DIMINISHED OVER MUCH OF THE REGION XPCT FAR E CENTRAL AREAS BUT XPCT THIS TO OCCUR THESE AREAS AS WELL OVER THE NXT HR OR TWO AS WELL. AS A RESULT...HAVE DROPPED THE REMAINING HVY SNOW WARNINGS AND SNOW ADVS. HAVE ISSUED A BLSN ADV ENTIRE FA AS BRISK NNW WNDS OF 15-25 MPH WITH GUSTS OVER 30 MPH AT TIMES WILL CAUSE CONSIDERABLE BLOWING AND DRIFTING SNOW. LOW PRESSURE OVER YARMOUTH NOVA SCOTIA EARLY THIS MORNING WILL CONTINUE TO TRACK EASTWARD TODAY BRINGING SNOW TO AN END FROM WEST TO EAST ACROSS THE STATE THIS MORNING. RUC MODEL INDICATES INTENSE SNOW BAND BETWEEN HOULTON AND DOVER- FOXCROFT SHOULD START TO WIND DOWN THIS MORNING AND SLOWLY MOVE INTO NEW BRUNSWICK. SNOW HAS TAPERED TO SNOW SHOWERS ACROSS DOWNEAST SECTIONS SO WILL DROP WARNING THERE BUT WILL LEAVE OTHER HEADLINES UP UNTIL 10 AM SINCE SNOW STILL OCCURRING ACROSS CENTRAL AND NORTHERN SECTIONS. ALL MODELS IN GOOD AGREEMENT THAT SNOW SHOULD PULL OUT OF THE STATE LATER THIS MORNING WITH SUN FOR MOST AREAS LATER THIS AFTERNOON. ARCTIC HIGH PRESSURE WILL BUILD INTO THE REGION TODAY UNDER A BRISK NORTHWEST WIND. EXPECT AREAS OF BLOWING AND DRIFTING SNOW ACROSS THE STATE TODAY EXCEPT ALONG COASTAL SECTIONS WHERE HEAVY WET SNOW WILL BE HARD TO BLOW. WITH WIND DIRECTION MORE NORTH THAN WEST, MOST VULNERABLE ROADS TO BLOWING SNOW WILL BE ONES ORIENTED NORTHEAST TO SOUTHWEST. CLEAR SKIES TONIGHT AS ARCTIC HIGH CONTINUES TO BUILD ACROSS THE REGION. COMBINATION OF NORTHWEST WINDS AND TEMPERATURES BELOW ZERO MAY CREATE WIND CHILLS AS LOW AS 20 BELOW OVER NORTHERN SECTIONS WHICH WOULD RESULT IN ADVISORY CRITERIA LATER TONIGHT. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... A BRISK NORTHERLY FLOW WILL COMBINE WITH SUBZERO TEMPERATURES ACROSS MUCH OF THE CWA TO RESULT IN POSSIBLE WIND CHILL ADVISORIES AT LEAST DURING THE MORNING HOURS ON THURSDAY. OTHERWISE AS HIGH PRESSURE RIDGES INTO THE REGION...THE PRESSURE GRADIENT AND WINDS WILL SLOWLY RELAX UNDER MOSTLY SUNNY SKIES DURING THURSDAY AFTERNOON. CLEAR SKIES WILL ALLOW TEMPERATURES TO PLUMMET WITH A FRESH SNOW PACK IN PLACE DURING THE FIRST HALF OF THURSDAY NIGHT. THEN CLOUDS RIDING ALONG THE TOP OF THE SURFACE RIDGE AND IN CONJUNCTION WITH SHORT WAVE ENERGY AND WEAK WAA APPROACHING FROM QUEBEC PROVINCE WILL MOVE IN STABILIZING TEMPERATURES AND POSSIBLY PRODUCE A FEW FLURRIES OR A SNOW SHOWERS OR TWO ACROSS THE NORTHERN ZONES LATE THURSDAY NIGHT OR EARLY FRIDAY MORNING. CLOUD SHOULD THIN DURING FRIDAY AFTERNOON. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... HIGH PRESSURE CENTERED ACROSS THE SOUTHEASTERN STATES WILL SETUP A RETURN FLOW OF WARMER AIR ACROSS THE REGION INTO THE WEEKEND AND EARLY NEXT WEEK. HAVE FOLLOWED GMOS GUIDANCE FOR THIS PORTION OF THE FORECAST WHICH FOR TEMPERATURES SHOWS THE MODERATION IN TEMPERATURES MAY BE MODULATED BY THE DEEP SNOW PACK ACROSS THE REGION. IN ANY EVENT...THE LOG TERM PORTION OF THE FORECAST MAY HAVE SOME MINOR DISTURBANCES MOVE THROUGH THE REGION OVER THE WEEKEND AND EARLY NEXT WEEK BUT NO MAJOR STORMS EXPECTED. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... IFR CONDITIONS THIS MORNING WILL GRADUALLY LIFT TO MVFR BY NOONTIME AND THEN VFR LATER THIS AFTERNOON AS SNOW MOVES OUT AND ARCTIC HIGH PRESSURE BUILDS ACROSS THE STATE. EXPECT VFR CONDITIONS ACROSS THE REGION FROM THURSDAY THROUGH THE UPCOMING WEEKEND. && .MARINE... NEAR TERM: WINDS HAVE SHIFTED TO THE NORTH THIS MORNING AS LOW PRESSURE HAS MOVED EAST OF THE WATERS. USED A BLEND OF THE NAM12 AND GFS FOR WINDS WHICH INDICATE A STRONG SCA FOR TODAY. HOWEVER, WITH GALE ALREADY UP AND GUSTS POSSIBLY TO 35 KTS THIS MORNING WILL KEEP GALE UP FOR NOW. WINDS SHOULD DECREASE ENOUGH LATER THIS AFTERNOON TO ALLOW WINDS TO DROP TO SCA LEVELS. WNAWAVE 2 TO 4 FT TOO LOW THIS MORNING SO WENT ABOVE THE WAVE GUIDANCE TODAY. SHORT TERM: EXPECT SCA CONDITIONS ESPECIALLY THURSDAY MORNING...THEN WITH THE GRADIENT AND CAA WANING CONDITIONS SHOULD GO BELOW HEADLINE CRITERIA INTO THE UPCOMING WEEKEND. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...BLOWING SNOW ADVISORY UNTIL 9 PM EST THIS EVENING FOR MEZ001>006-010-011-015>017-029>032. MARINE...GALE WARNING UNTIL 6 PM EST THIS AFTERNOON FOR ANZ050>052. && $$ NEAR TERM...FOSTER/KHW SHORT TERM...FITZSIMMONS LONG TERM...FITZSIMMONS AVIATION...FOSTER/KHW MARINE...FOSTER/KHW/FITZSIMMONS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 631 AM EST WED JAN 2 2008 .SYNOPSIS... LOW PRESSURE WILL CONTINUE TO INTENSIFY AS IT MOVES EAST OF NOVA SCOTIA THROUGH TONIGHT. COLD ARCTIC AIR WILL FOLLOW THIS SYSTEM ON BRISK NORTHERLY WINDS LATER TODAY AND TONIGHT. AS HIGH PRESSURE BECOMES ESTABLISHED OVER THE SOUTHEASTERN STATES...THE RETURN FLOW WILL RESULT IN A GRADUAL WARMING TREND FOR THE REGION BEGIN OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LOW PRESSURE OVER YARMOUTH NOVA SCOTIA EARLY THIS MORNING WILL CONTINUE TO TRACK EASTWARD TODAY BRINGING SNOW TO AN END FROM WEST TO EAST ACROSS THE STATE THIS MORNING. RUC MODEL INDICATES INTENSE SNOW BAND BETWEEN HOULTON AND DOVER-FOXCROFT SHOULD START TO WIND DOWN THIS MORNING AND SLOWLY MOVE INTO NEW BRUNSWICK. SNOW HAS TAPERED TO SNOW SHOWERS ACROSS DOWNEAST SECTIONS SO WILL DROP WARNING THERE BUT WILL LEAVE OTHER HEADLINES UP UNTIL 10 AM SINCE SNOW STILL OCCURRING ACROSS CENTRAL AND NORTHERN SECTIONS. ALL MODELS IN GOOD AGREEMENT THAT SNOW SHOULD PULL OUT OF THE STATE LATER THIS MORNING WITH SUN FOR MOST AREAS LATER THIS AFTERNOON. ARCTIC HIGH PRESSURE WILL BUILD INTO THE REGION TODAY UNDER A BRISK NORTHWEST WIND. EXPECT AREAS OF BLOWING AND DRIFTING SNOW ACROSS THE STATE TODAY EXCEPT ALONG COASTAL SECTIONS WHERE HEAVY WET SNOW WILL BE HARD TO BLOW. WITH WIND DIRECTION MORE NORTH THAN WEST, MOST VULNERABLE ROADS TO BLOWING SNOW WILL BE ONES ORIENTED NORTHEAST TO SOUTHWEST. CLEAR SKIES TONIGHT AS ARCTIC HIGH CONTINUES TO BUILD ACROSS THE REGION. COMBINATION OF NORTHWEST WINDS AND TEMPERATURES BELOW ZERO MAY CREATE WIND CHILLS AS LOW AS 20 BELOW OVER NORTHERN SECTIONS WHICH WOULD RESULT IN ADVISORY CRITERIA LATER TONIGHT. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... A BRISK NORTHERLY FLOW WILL COMBINE WITH SUBZERO TEMPERATURES ACROSS MUCH OF THE CWA TO RESULT IN POSSIBLE WIND CHILL ADVISORIES AT LEAST DURING THE MORNING HOURS ON THURSDAY. OTHERWISE AS HIGH PRESSURE RIDGES INTO THE REGION...THE PRESSURE GRADIENT AND WINDS WILL SLOWLY RELAX UNDER MOSTLY SUNNY SKIES DURING THURSDAY AFTERNOON. CLEAR SKIES WILL ALLOW TEMPERATURES TO PLUMMET WITH A FRESH SNOW PACK IN PLACE DURING THE FIRST HALF OF THURSDAY NIGHT. THEN CLOUDS RIDING ALONG THE TOP OF THE SURFACE RIDGE AND IN CONJUNCTION WITH SHORT WAVE ENERGY AND WEAK WAA APPROACHING FROM QUEBEC PROVINCE WILL MOVE IN STABILIZING TEMPERATURES AND POSSIBLY PRODUCE A FEW FLURRIES OR A SNOW SHOWERS OR TWO ACROSS THE NORTHERN ZONES LATE THURSDAY NIGHT OR EARLY FRIDAY MORNING. CLOUD SHOULD THIN DURING FRIDAY AFTERNOON. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... HIGH PRESSURE CENTERED ACROSS THE SOUTHEASTERN STATES WILL SETUP A RETURN FLOW OF WARMER AIR ACROSS THE REGION INTO THE WEEKEND AND EARLY NEXT WEEK. HAVE FOLLOWED GMOS GUIDANCE FOR THIS PORTION OF THE FORECAST WHICH FOR TEMPERATURES SHOWS THE MODERATION IN TEMPERATURES MAY BE MODULATED BY THE DEEP SNOW PACK ACROSS THE REGION. IN ANY EVENT...THE LOG TERM PORTION OF THE FORECAST MAY HAVE SOME MINOR DISTURBANCES MOVE THROUGH THE REGION OVER THE WEEKEND AND EARLY NEXT WEEK BUT NO MAJOR STORMS EXPECTED. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... IFR CONDITIONS THIS MORNING WILL GRADUALLY LIFT TO MVFR BY NOONTIME AND THEN VFR LATER THIS AFTERNOON AS SNOW MOVES OUT AND ARCTIC HIGH PRESSURE BUILDS ACROSS THE STATE. EXPECT VFR CONDITIONS ACROSS THE REGION FROM THURSDAY THROUGH THE UPCOMING WEEKEND. && .MARINE... NEAR TERM: WINDS HAVE SHIFTED TO THE NORTH THIS MORNING AS LOW PRESSURE HAS MOVED EAST OF THE WATERS. USED A BLEND OF THE NAM12 AND GFS FOR WINDS WHICH INDICATE A STRONG SCA FOR TODAY. HOWEVER, WITH GALE ALREADY UP AND GUSTS POSSIBLY TO 35 KTS THIS MORNING WILL KEEP GALE UP FOR NOW. WINDS SHOULD DECREASE ENOUGH LATER THIS AFTERNOON TO ALLOW WINDS TO DROP TO SCA LEVELS. WNAWAVE 2 TO 4 FT TOO LOW THIS MORNING SO WENT ABOVE THE WAVE GUIDANCE TODAY. SHORT TERM: EXPECT SCA CONDITIONS ESPECIALLY THURSDAY MORNING...THEN WITH THE GRADIENT AND CAA WANING CONDITIONS SHOULD GO BELOW HEADLINE CRITERIA INTO THE UPCOMING WEEKEND. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...HEAVY SNOW WARNING UNTIL 10 AM EST THIS MORNING FOR MEZ002- 004>006-010-011-031-032. SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR MEZ001-003. MARINE...GALE WARNING UNTIL 6 PM EST THIS AFTERNOON FOR ANZ050>052. && $$ NEAR TERM...FOSTER SHORT TERM...FITZSIMMONS LONG TERM...FITZSIMMONS AVIATION...FOSTER MARINE...FOSTER/FITZSIMMONS me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 844 PM EST WED JAN 2 2008 .SYNOPSIS... LIGHT SNOW SHOWERS WILL BE ENDING THURSDAY AS HIGH PRESSURE BUILDS INTO THE UPPER OHIO VALLEY. AS THIS HIGH PRESSURE PASSES EAST OF THE AREA FRIDAY SOUTHERLY WINDS WILL BRING MILDER TEMPERATURES. A WEAK WARM FRONT MAY BRING RAIN SHOWERS SATURDAY. && .NEAR TERM /THROUGH THURSDAY/... JUDGING FROM A BLEND OF RECENT RADAR AND SURFACE DATA COUPLED WITH RECENT NAM AND RUC MODEL RUNS...EXPECT THE SCATTERED LIGHT SNOW SHOWERS FROM THE GREAT LAKES AFFECTING OHIO AND WEST VIRGINIA TO SHIFT EASTWARD INTO THE REST OF THE UPPER OHIO VALLEY OVERNIGHT AND THURSDAY MORNING. SNOW AMOUNTS OF UP TO 1 INCH WERE FORECASTED FOR ONLY THE WEST VIRGINIA AND PERHAPS MARYLAND MOUNTAINS. AS THE GREAT PLAINS HIGH PRESSURE CENTER MOVES EASTWARD, THE BOUNDARY LAYER WILL FURTHER STABILIZE, ENDING THE SHOWERS AND DECREASING THE CLOUD COVER. FORECASTED LOW TEMPERATURES TONIGHT HAVE BEEN LOWERED AS READING HAVE BEEN DROPPING OVER THE FRESH SNOW COVER. THE FALL SHOULD SLOW DOWN LATE TONIGHT AS THE CLOUDS OVER OHIO SPREAD EASTWARD INTO PENNSYLVANIA. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... CLEAR AND COLD THURSDAY NIGHT UNDER HIGH PRESSURE THEN SUNSHINE AND BACK TOWARD NORMAL TEMPERATURES FOR FRIDAY. TEMPERATURES WARMING ABOVE NORMAL FRIDAY NIGHT IN SOUTHWEST FLOW BEHIND SURFACE HIGH. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... SHORTWAVE WILL BE MOVING QUICKLY EAST AS FLOW ALOFT BECOMES ZONAL WITH A SOUTHWESTERLY ORIENTATION THIS PERIOD. THERE IS THE POTENTIAL FOR RAIN SHOWERS AS A WEAK WARM FRONT DEVELOPS IN THE INITIAL LOWLEVEL PUSH OF MILDER GULF AIR SURGE LATE SATURDAY INTO SUNDAY. AN ENSUING RIDGE BUILDS ACROSS EASTERN U.S. INTO TUESDAY WITH MUCH ABOVE NORMAL TEMPERATURES AND GENERALLY DRY CONDITIONS. A DEEPENING STORM SYSTEM MOVING EAST FROM PLAINS STATES WILL BRING RAIN BACK INTO REGION WEDNESDAY. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... CONDITIONS WILL GENERALLY BE VFR AS THE NORTHWESTERLY FLOW WEAKENS TONIGHT THERE COULD STILL BE SOME LINGERING SNOW SHOWERS GIVING SCATTERED MVFR AND IFR CONDITIONS INTO THURSDAY MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE REGION ON THURSDAY AND MOVE EAST ACROSS THE UPPER OHIO VALLEY FRIDAY BRINGING VFR CONDITIONS. A SHORT WAVE TROUGH WILL TRACK EASTWARD THROUGH THE REGION SATURDAY INTO SUNDAY BRINGING RAIN SHOWERS AND POSSIBLE MVFR/IFR CONDITIONS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1057 PM EST WED JAN 2 2008 .UPDATE...NORTHWEST FLOW LAKE EFEFCT CONTINUES TO ROLL ON GIVEN INFLUX OF COLDEST AIRMASS OVER THE PAST SEVERAL HOURS (H85 TEMPS DIPPING TO ABOUT -18C PER RAOBS/RUC GUIDANCE) AND PASSAGE OF SUBTLE 700-500MB WAVE COUPLED WITH MORE THAN SUFFICIENT DEEP LAYER MOISTURE...AS 900-700MB RH CONTINUES TO HOLD ABOUT 85%. HOWEVER...CHANGES ON THE WAY LATE TONIGHT AS LOW LEVEL RIDGE AXIS ALREADY MAKING QUICK PROGRESS INTO THE U.P./UPPER MIDWEST...WITH OVERALL 1000-850 MB FLOW TURNING WEST AND THEN SOUTHWEST AND BEGINNING TO HAVE SOME SUBTLE EFFECT PER UPSTREAM MQT RADAR DEPICTING A SUBTLE SHIFT IN BANDING STRUCTURE. EXPECT THIS TREND WILL CONTINUE INTO THE EARLY MORNING HOURS...AS LOW LEVEL RIDGING TAKES OVER AND INVERSION HEIGHTS CRASH PER ARRIVAL OF 1000-500MB DEEP LAYER RIDGING AND SUBSEQUENT DRYING/LOSS OF MOISTURE ALOFT. IN TYPICAL LAKE EFFECT FASHION...ONGOING MOMENTUM OF SNOW BANDS LIKELY TO CARRY THE PRECIP A BIT LONGER THAN MODELS WOULD SUGGEST (ESPECIALLY WITH INITIAL SUPERIOR CONNECTION)...AND WILL THEREFORE HOLD ONTO HIGH POPS THROUGH ABOUT 09Z AS SHOULD SEE SOME BANDS CONTINUE BEFORE QUICKLY ERODING BY SUNRISE. LITTLE IN THE WAY OF ANY ADDITIONAL ACCUMULATIONS PER ONGOING LOSS OF MOISTURE SUPPORT...BUT PERHAPS UP TO AN INCH IF ANY BANDS CAN HOLD STILL LONG ENOUGH. TEMPERATURES OVERNIGHT QUITE IFFY. OVERALL HAVE RAISED GOING NUMBERS A TAD MOST SPOTS (MOST NOTICEABLE OVER NORTHWEST LOWER MICHIGAN WHERE ONSHORE FLOW WILL CONTINUE THROUGH THE NIGHT) AS EXPECT CLOUD COVER TO LINGER A BIT LONGER...AND UPSTREAM THICK JET-DRIVEN CIRRUS SHIELD WILL OVERSPREAD THE AREA AS WELL. HOWEVER...ALSO DEALING WITH EXCELLENT DRAINAGE FLOW OUT OF ONTARIO...WITH NUMBERS TUMBLING OVER EASTERN UPPER. EXPECT THIS SAME FLOW WILL EVENTUALLY BLEED OUT ACROSS LAKE HURON AND INTO NORTHERN LOWER...SO GOING NUMBERS AROUND 0 TO 5 LOOK A GOOD BET BY MORNING...BUT AGAIN WILL HAVE TO WATCH PROGRESSION OF CLOUDS AND POTENTIAL RELOCATION OF LAKE HURON STRATOCU DECK INTO NORTHEAST LOWER AS FLOW TRIES TO KICK NORTHEAST. UPDATED GRIDS/ZONES ALREADY OUT. LAWRENCE && .AVIATION... /ISSUED 636 PM EST WED JAN 2 2008/ LAKE EFFECT SNOW SHOWERS WILL PREVAIL THROUGH THE 06-09Z TIMEFRAME BEFORE MUCH DRIER AIR WINS OUT AND OVERALL FLOW REGIME QUICKLY SHIFTS SOUTHWEST BY MORNING. PRIOR TO THAT TIME...A MIX OF MVFR TO OCCASIONAL HIGH END IFR CONDITIONS EXPECTED AT TIMES FOR KTVC/KPLN AS SNOW SHOWERS CONTINUE. EXPECT MAINLY VFR CONDITIONS FOR KAPN...THOUGH WILL HAVE TO WATCH POTENTIAL FOR SOME LOWER CEILINGS TO DRIFT IN FROM EXPECTED LAKE HURON SNOW BAND. DEVELOPING SOUTHWEST FLOW AND INTRUSION OF DRYING SHOULD LEAD TO A LOSS OF STRATOCU LATE TONIGHT...THOUGH JET- INDUCED CIRRUS SHIELD OVER THE NORTHERN PLAINS WILL SLIDE OVERHEAD AND PERSIST THROUGH 00Z TOMORROW. WINDS WILL ALSO BE ON THE INCREASE THROUGH THE DAY...WITH GUSTY CONDITIONS EXPECTED BY AFTERNOON AS GRADIENT TIGHTENS WITH STRONG HIGH TO THE SOUTH AND TROUGH CUTTING THROUGH CENTRAL ONTARIO. SOME SMALL POTENTIAL AS WELL FOR STRATOCU DECK TO ONCE AGAIN OVERSPREAD THE REGION BY EARLY AFTERNOON AS PERSISTENT OVER-LAKE SOUTHWEST FLOW MAY OVERCOME OVERALL DRYNESS...THOUGH CONFIDENCE SUFFICIENTLY LOW TO PRECLUDE ANY MENTION AT THIS TIME. LAWRENCE && DISCUSSION... /ISSUED 323 PM EST WED JAN 2 2008/ QUICK BURST OF LAKE EFFECT SNOW (LES) HAS PROGRESSED THRU EASTERN UPPER MI...AND IS ON TARGET TO DO THE SAME IN NORTHERN LOWER MI OVER THE NEXT SEVERAL HOURS. ARCTIC HIGH PRESSURE IN THE PLAINS WILL MOVE TO MO TONIGHT...AND TO KY/TN THURSDAY. RIDGE AXIS WILL CROSS MI EARLY THURSDAY MORNING...WITH STRONG WARM ADVECTION BY AFTERNOON AS SAID RIDGE MOVES EAST. PRECIP TRENDS THIS EVENING ARE THE MAIN FORECAST CONCERN. TONIGHT...SURFACE TROF AXIS NOW MOVING SOUTH ACROSS FAR NORTHERN LAKE MI...WITH A SMALL BULLSEYE OF MID LEVEL MOISTURE (850-700MB RH TO 90 PERCENT) ALONG FOR THE RIDE. THIS WILL BRING LES TO NW LOWER MI FROM LATE AFTERNOON THRU MID EVENING. PERIOD OF SYNOPTIC ASSISTANCE IS BRIEF...BY MIDNIGHT THE BETTER MOISTURE IS WELL DOWNSTATE...AND WE/RE FIGHTING OFF DRY AIR ADVECTION. GIVEN THE COMBINATION OF LOW LEVEL CONVERGENCE WITH THE TROF...DELTA T/S NEAR 20...AND MID LEVEL MOISTURE...ISOLATED BURSTS OF INCH/HR SNOWS IS POSSIBLE (AND OCCURRED IN LUCE CO AT MIDDAY). BUT THAT COMBINATION OF ELEMENTS WILL NOT LAST LONG AT ALL...AND BANDS WILL NOT GET A CHANCE TO GET ORGANIZED BEFORE THINGS START TO SHUT DOWN. SO WILL REDUCE SNOW ACCUMS A BIT FURTHER...WITH ONLY ISOLATED 2-INCH TOTALS POSSIBLE WEST OF I-75 IN THE LATE AFTERNOON/EVENING HOURS. FOR OVERNIGHT...INSTABILITY REMAINS PLENTY SUFFICIENT FOR VIGOROUS LES IN BORDERLINE NNW/NW FLOW. HOWEVER...MOISTURE IS FALLING OFF THE TABLE (850-700MB RH 50 PERCENT AT 06Z...40 PERCENT AT 09Z). PERHAPS MORE SIGNIFICANTLY...BIG RIDGING ARRIVES ON SUPERIOR AT 06Z...AND OUR WINDS WILL BE BACKING WEST TOWARD DAWN. THE LOSS OF THE SUPERIOR CONNECTION AND ARRIVAL OF ANTICYCLONIC FLOW WILL SPELL THE END OF LES. AND...IT/S WORTH NOTING THAT LES ON SUPERIOR NOW (BEHIND THE SURFACE TROF) IS LESS THAN IMPRESSIVE. END RESULT...JUST SCT LES IN THE SNOWBELTS OVERNIGHT...WITH MINIMAL ACCUMS. TEMPS OUTSIDE OF LES AREAS WILL AGAIN BE QUITE COLD...WITH SUB-ZERO READINGS LIKELY IN PLACES LIKE THE SAULT AND PLN. LAKE MI COASTAL LOCALES WILL SEE MINS CLOSER TO 10F. THURSDAY...BROAD RIDGING ALOFT WILL BE BUILDING ACROSS MID- CONTINENT. A SHORTWAVE EMBEDDED WITHIN THE RIDGE WILL PASS NORTH OF SUPERIOR DURING THE DAY. THIS COULD BRING SOME CLOUD COVER TO CHIPPEWA COUNTY...MAINLY DURING THE AFTERNOON. HOWEVER...WEDGE OF DRY AIR BETWEEN 900 AND 700MB SHOULD LIMIT CHANCE OF PRECIP REACHING THE GROUND (IF ANYTHING...MAYBE A FLURRY OR TWO AT MOST...AND WILL NOT INCLUDE IN THE FORECAST FOR NOW). OTHERWISE...INTENSE WARM ADVECTION WILL OCCUR...BUT MAINLY ABOVE 900MB. STILL RELATIVELY COOL (AND MOIST) AIR TRAPPED BELOW 900MB. SO WE WILL STAY COOLISH (NOT AS COLD AS TODAY) AND MAINLY CLOUDY (BETWEEN LOW CLOUDS...AND THE CIRRUS SHIELD HEADING OUR WAY FROM MANITOBA). MAX TEMPS WILL BE MAINLY IN THE 20S...NEAR 30 AROUND TVC...THOUGH A BRISK SOUTHWEST WIND WILL MAKE IT FEEL CHILLIER. SPEAKING OF WHICH...WILL ISSUE GALE WARNINGS FOR THE LAKE MI MARINE ZONES AND FOR WHITEFISH BAY FOR VERY LATE THURSDAY THRU FRIDAY MORNING...THANKS TO STRONG SW WINDS. ZOLTOWSKI REST OF THE FORECAST (THURSDAY NIGHT THROUGH NEXT WEDNESDAY)...PATTERN CHANGE STILL APPEARS TO BE ON TRACK OVER THE NEXT SEVERAL DAYS AS A DEEP WESTERN TROUGH FORCES DOWNSTREAM RIDGING ACROSS THE EAST COAST. THEREFORE...A WARMUP IS ON TAP LATER IN THE WEEKEND INTO EARLY NEXT WEEK. IN THE MEANTIME...MODERATING TEMPERATURES ARE EXPECTED TO ROUND OUT THE ABBREVIATED WORK WEEK INTO THE FIRST HALF OF THE WEEKEND. THE MAIN FORECAST CONCERNS WILL REVOLVE AROUND POPS THIS WEEKEND INTO NEXT WEEK AND JUST HOW WARM TEMPERATURES WILL GET. THURSDAY NIGHT INTO FRIDAY...UPPER LEVEL HEIGHTS WILL LEVEL OFF RESULTING IN A NEARLY ZONAL FLOW. MODEL CROSS SECTIONS/SOUNDINGS SHOW QUITE A BIT OF UPPER LEVEL MOISTURE BUT DRY MID AND LOWER LEVELS (MEAN 850-500 MB RH 35 TO 45 PERCENT) SO PARTLY CLOUDY SKIES SHOULD WORK. SOUTHWEST SURFACE FLOW WILL CONTINUE WITH PROGRESSIVELY MILDER AIR MOVING IN FROM THE SOUTH. THE BREEZE WILL KEEP TEMPERATURES FROM FALLING TOO MUCH THURSDAY NIGHT WITH LOWS IN THE TEENS TO LOWER 20S EXPECTED. GALES WILL CONTINUE ACROSS LAKE MICHIGAN ZONES ALONG WITH WHITEFISH BAY. HIGHS FRIDAY IN THE UPPER 20S TO LOWER 30S. FRIDAY NIGHT INTO SATURDAY...MODELS BEGIN TO DIVERGE JUST A BIT DURING THIS TIME PERIOD. THE GFS CONTINUES TO BRING A RIPPLE THROUGH THE FLOW WHICH SLOWS WARMUP JUST A TAD AS WELL AS POSSIBLY BRINGING IN A CHANCE OF SNOW OR RAIN SHOWERS. THE NAM/LAST NIGHTS ECMWF ARE MUCH MORE BULLISH WITH THE WARM AIR AND ARE MUCH DRIER. FOR NOW WILL CONTINUE WITH THE LOW CHANCE POPS AND ADD SNOW SHOWERS INTO THE RAIN SHOWERS AS GFS/UKMET WOULD BE COLD ENOUGH...ESPECIALLY IN THE MORNING TO SUPPORT THIS. LOWS FRIDAY NIGHT MAINLY IN THE 20S (WITH PERHAPS A FEW UPPER TEENS EAST). HIGHS SATURDAY IN THE MIDDLE TO PERHAPS UPPER 30S. SATURDAY NIGHT INTO SUNDAY...THE TROUGH CENTERED ACROSS THE WESTERN STATES CONTINUES TO AMPLIFY WHILE SENDING MINOR PIECES OF ENERGY NORTHEAST TOWARD THE REGION. WOULD NOT BE SURPRISED THOUGH IF THIS ENERGY REMAINS MAINLY TO OUR WEST BUT WILL CONTINUE WITH LOW CHANCE POPS TO MAINTAIN CONSISTENCY/LINE UP WITH SURROUNDING OFFICES. IN ADDITION...WITH WARMER AIR OVERRIDING THE SLOWLY MELTING SNOWPACK...WILL ADD IN AREAS OF FOG. LOWS SATURDAY NIGHT NOT FALLING TO MUCH FROM HIGHS ON SATURDAY (LOWER TO MIDDLE 30S) WITH HIGHS SUNDAY CREEPING UP INTO THE LOWER AND MIDDLE 40S. MONDAY AND TUESDAY...WESTERN TROUGH MOVES SLOWLY TO THE EAST BRINGING A BETTER CHANCE OF RAIN TO THE WESTERN GREAT LAKES. EXTENDED MODELS VARY AS TO THE TIMING/DEPTH OF SURFACE DEVELOPMENT BUT THERE IS THE POTENTIAL FOR A DECENT AMOUNT OF RAIN AT SOME POINT DURING THIS TIME WITH MORE FOG. THE SNOWMELT AND RAINFALL MAY EVENTUALLY LEAD TO HYDROLOGIC CONCERNS AS WELL. HIGHS IN THE 40S TO LOWER 50S. WEDNESDAY...TROUGH AXIS IS EXPECTED TO CREEP CLOSER TO THE REGION WITH MORE SEASONABLE AIR ARRIVING FROM THE NORTHWEST. WILL HAVE A CHANCE OF RAIN AND SNOW SHOWERS AS MOISTURE LINGERS BEHIND THE DEPARTING SYSTEM AND SURFACE COLD FRONT. NOT AS WARM WITH TEMPERATURES MAINLY IN THE 30S TO LOWER 40S. SULLIVAN && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING FROM 4 PM THURSDAY TO 10 AM EST FRIDAY FOR LMZ323- 341-342-344>346. LH...NONE. LS...GALE WARNING FROM 4 PM THURSDAY TO 10 AM EST FRIDAY FOR LSZ321. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 630 PM EST WED JAN 2 2008 .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER NAMERICA WITH A RIDGE OVER THE ROCKIES AND A TROF OVER THE ERN THIRD OF THE CONUS. PATTERN IS BECOMING PROGRESSIVE WITH SIGNIFICANT HEIGHT RISES NOTED OVER THE NRN PLAINS INTO SCNTRL CANADA (12Z RAOBS SHOWED 12HR 500MB HEIGHT RISES UPWARDS OF 180M). WITH THE RIDGE SLIDING EWD...PACIFIC AIR/DEVELOPING STRONG WAA PATTERN HAS PRODUCED A HUGE AREA OF HIGH CLOUDS ACROSS CNTRL CANADA INTO THE NRN PLAINS. AT THE SFC...HIGH PRES RIDGE EXTENDS FROM TX TO MN. LES OFF LAKE SUPERIOR HAS BEEN WINDING DOWN THIS AFTN...MOST NOTABLY OVER THE W WHERE LATEST VIS IMAGERY SHOWS LITTLE ORGANIZED LES REMAINING. && .SHORT TERM (TONIGHT AND THU)... MAIN FCST ISSUE IS ENDING LES TONIGHT/MIN TEMPS TONIGHT AND WINDS THU. WITH SFC RIDGE REACHING WRN LAKE SUPERIOR EARLY THIS EVENING AND THEN SLIDING E OF THE LAKE AROUND 09Z...LES WILL END FROM W TO E TONIGHT AS WINDS BACK TO THE SW OR S. OPTED TO CANCEL ONGOING ADVYS OVER THE ERN COUNTIES WITH THIS FCST ISSUANCE AS LES IS CURRENTLY NOT ORGANIZED INTO SIGNIFICANT BANDS. THERE WILL PROBABLY BE SOME BURSTS OF SNOW WITH VIS DOWN TO 1/2SM EARLY THIS EVENING...BUT THOSE OCCURRENCES WILL BE VERY SHORT LIVED. MAY SEE ACCUMULATIONS AROUND 1 INCH THRU 00Z WITH ANOTHER 1 INCH TONIGHT BEFORE SNOW ENDS. TEMPS TONIGHT WILL BE A TRICKY. WITH SFC RIDGE PASSING DURING THE NIGHT AND STRATOCU SCATTERING OUT WITH THE RIDGE PASSAGE...THERE WILL BE AN OPPORTUNITY FOR TEMPS TO PLUMMET. THERE ARE A COUPLE OF COMPLICATING FACTORS. FIRST...CI AND HIGH BASED AS/AC CLOUDS ARE RAPIDLY SPREADING ESE INTO MN/NRN ONTARIO...AND SECOND...RETURN FLOW ON THE BACKSIDE OF THE HIGH RAPIDLY INCREASES...AIDED BY SIGNIFICANT PRES FALLS. LATEST ANALYSIS SHOWS 3HR PRES FALLS REACHING AN IMPRESSIVE 10MB ACROSS ERN SASKATCHEWAN/MANITOBA. ALTHOUGH THESE NEGATIVES FOR A STRONG SFC TEMP FALL (CLOUDS/INCREASING WINDS) WILL QUICKLY ARRIVE AFTER RIDGE PASSAGE...THERE SHOULD STILL BE A SHORT WINDOW OF 2 TO PERHAPS 4HRS OF GOOD TO EXCELLENT RADIATIONAL COOLING IN MOST AREAS...ESPECIALLY WHERE NEW SNOW HAS ACCUMULATED. HAVE THUS GONE BLO LOWEST MOS GUIDANCE...GENERALLY AROUND -5F IN MUCH OF THE INTERIOR (AS LOW AS -10F AT CHAMPION). WINDS WILL BE THE MAIN FEATURE THU UNDER TIGHT PRES GRADIENT BTWN DEPARTING STRONG SFC HIGH PRES RIDGE AND LOW PRES TRACKING TO HUDSON BAY. ALTHOUGH THIS WILL BE A WAA PATTERN OVER A SHALLOW EXITING ARCTIC AIRMASS...SITUATION IS STILL FAVORABLE FOR WINDY CONDITIONS. FORTUNATELY...THERE WILL BE SOME STABILITY AS GFS/NAM SHOW 60KT AT 3KFT. BIGGEST FACTOR SUPPORTING/ENHANCING SW WINDS WILL BE THE STRONG SFC PRES FALLS (8-10MB/3HR) SPREADING E ACROSS ONTARIO THU. EXPECT TO SEE WIND GUSTS UPWARDS OF 35-40MPH ACROSS MUCH OF THE N AND E LATE THU MORNING THRU AT LEAST MID AFTN. WITH UNCERTAINTY ON HOW STABILITY WILL AFFECT THE INCREASE IN WINDS...KEPT WINDS BLO ADVY CRITERIA FOR THIS FCST ISSUANCE. THE STRONG WAA PATTERN WILL ALSO LEAD TO CONSIDERABLE MID/HIGH CLOUDS THU AS IS OCCURRING UPSTREAM THIS AFTN. LOWER LEVELS APPEAR PLENTY DRY ENOUGH THOUGH TO PRECLUDE ANY MENTION OF PCPN. KEPT MAX TEMPS A BIT BLO ALL MOS GUIDANCE GIVEN CLOUDS AND CONSIDERABLE SNOW COVER UPSTREAM WHICH WILL TEMPER WARMING AT THE SFC. && .LONG TERM (THURSDAY NIGHT THROUGH NEXT WEDNESDAY)... THU NIGHT THROUGH FRI NIGHT...WINDS DECOUPLE AS 925MB WINDS REMAIN FROM THE WSW AND 850MB WINDS BECOME WNW...ESPECIALLY OVER THE WEST HALF OF THE LAKE. BY 06Z FRI...WINDS COUPLE UP OUT OF THE WEST BUT REMAIN RELATIVELY LIGHT THROUGH SUN. KEPT WX GRIDS DRY THROUGH FRI NIGHT AS LITTLE MOISTURE AND EVEN LESS FORCING WILL BE PRESENT OVER THE CWA. SATURDAY...KEPT SCHC FREEZING DRIZZLE IN FCST FOR 12-18Z SAT. NAM AND GFS BOTH SUPPORT IT BY A THICK DRY LAYER FROM AROUND 900-600MB AND THEN A SATURATED LAYER BELOW. A WEAK SHORTWAVE AT 500MB CREATING WEAK POSITIVE VORTICITY ADVECTION INTO OUR CWA...AND CORRESPONDING SLIGHTLY NEGATIVE OMEGA VALUES...AS WELL AS TEMPS ALL > -10C...MAY SUPPORT ENOUGH LIFT FOR THE DRIZZLE. THE SFC TEMP IS PROGGED TO BE BELOW FREEZING UNTIL AROUND 18Z. FROM 18Z SAT TO 00Z SUN...KEPT THE SCHC OF RAIN SINCE THE GFS IS SHOWING A LITTLE DEEPER MOISTURE... ADDITIONAL PVA AND SLIGHTLY GREATER LIFTING ON ISENTROPIC SURFACES. AS FAR AS P-TYPE GOES...THE ECMWF SOLN SUPPORTS RAIN IN THE AFTERNOON. THE GFS IS THE COLDER SOLN WHEN COMPARED TO THE ECMWF; THE GFS DOES NOT HAVE THE 1500FT WET BULB ZERO HEIGHT INTO THE U.P. UNTIL 00Z SUN...WHILE THE ECMWF HAS IT IN THE CWA BETWEEN 12Z SAT AND 00Z SUN. THE WET BULB ZERO HEIGHTS SUPPORT RAIN FROM SAT NIGHT THROUGH MON NIGHT. SUNDAY...WHILE WAA IS PREVALENT ON SUN...LACK OF UPPER LEVEL FORCING AND OVERALL MOISTURE MAY INHIBIT THE CHANCE OF RAIN WE HAVE GOING. BACKED OFF POPS TO 30 PERCENT. THERE MAY JUST BE LOW CLOUDS...FOG OR DRIZZLE FOR SUN AND SUN NIGHT. WILL NEED TO KEEP AN EYE ON THIS DURING THE NEXT FCST UPDATE. SUNDAY NIGHT THROUGH MONDAY NIGHT...LOW LEVEL OMEGA VALUES OF AROUND 0 TO -1 ARE FAVORABLE FOR LIFT OVER THE EAST HALF ON 00Z MON-00Z TUE...BUT NOT AS FAVORABLE OVER THE WEST. 280K GFS ISENTROPIC SFC INDICATES WEAK SUBSIDENCE OVER THE WEST MON 18Z. CUT BACK POPS TO 30 OVER FAR WEST ACCORDINGLY. POSITIVE VORTICITY ADVECTION OVER THE EAST HALF ON TUE WILL CREATE A BETTER CHANCE FOR PCPN. KEPT GOING POPS OF 50 IN THE EAST HALF AND SOUTH CENTRAL. TUESDAY THROUGH WEDNESDAY...00Z ECMWF AND 06Z GFS NOW BOTH SHOW A CLOSED LOW OVER THE MIDWEST AT 12Z TUE...THE ECMWF STRONGER OF THE TWO. THE GFS HAS A MORE ELONGATED SHAPE AND ONLY HAS THE EAST HALF IN THE WARM SECTOR...WITH 850MB TEMPS ABOVE FREEZING THROUGH WED 18Z. THE ECMWF KEEPS THE ENTIRE U.P. IN THE WARM SECTOR...WITH 850MB TEMPS ABOVE FREEZING THROUGH WED 12Z...AS THE CENTER OF THE LOW TRACKS ACROSS FAR WESTERN UPPER MI ON WED MORNING. THERE IS A GENERAL CONSENSUS THAT THERE WILL BE SOME SORT OF PCPN (GFS/ECMWF SUPPORT) TUE 12Z-WED 12Z. MADE WEST HALF CHANCE OF RAIN OR SNOW AND EAST HALF CHANCE OF RAIN THROUGH WED 12Z...THEN MADE ENTIRE CWA CHANCE OF RAIN OR SNOW WED 12Z-THU 00Z TO REFLECT THE MODEL UNCERTAINTY. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... LIGHT WESTERLY FLOW WILL BECOME MORE SOUTHWESTERLY OVERNIGHT AND INCREASE SIGNIFICANTLY OVER THE LAST 12 HOURS OF THE FORECAST PERIOD. THE INCREASED WIND...ALONG WITH NEWLY FALLEN SNOW...WILL ALLOW FOR POTENTIAL BLOWING SNOW MAINLY AFTER 15Z. HAVE LOWERED CIGS FOR THIS FORECAST...BUT STILL KEEP THEM ABOVE BKNO35. WILL NEED TO MONITOR POTENTIAL LOWER CLOUDS AFTER 21Z AT CMX AND POSSIBLY STRONGER WINDS THAN FORECAST AT BOTH SITES. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS WILL GENERALLY DIMINISH INTO THE 5 TO 15 KT RANGE TONIGHT AS SFC HIGH PRES RIDGE QUICKLY SLIDES ACROSS LAKE SUPERIOR. HOWEVER... LIGHT WINDS WILL BE SHORT LIVED AS TIGHT PRES GRADIENT DEVELOPS BTWN THE DEPARTING STRONG SFC HIGH PRES RIDGE AND LOW PRES TRACKING E TO HUDSON BAY. WITH AIRMASS NOT FULLY STABLE OVER LAKE SUPERIOR AND IMPRESSIVE PRES FALLS ACROSS ONTARIO ENHANCING S TO SW WINDS...STAGE WILL BE SET FOR SOLID GALES THU. EXPECT TO SEE SOME GUSTS TO 45KT... AND NOT OUT OF THE QUESTION THAT A FEW GUSTS COULD REACH 50KT BTWN THE KEWEENAW AND ISLE ROYALE. WINDS WILL DIMINISH THU EVENING/NIGHT. NO GALES ARE EXPECTED FOR THE REMAINDER OF THE FCST PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING IN EFFECT FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR LSZ162-249>251-263>267. GALE WARNING IN EFFECT FROM THURSDAY AFTERNOON THROUGH THURSDAY NIGHT FOR LMZ221-248-250. && $$ SYNOPSIS/SHORT TERM...ROLFSON LONG TERM...MRC AVIATION...KF MARINE...ROLFSON mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1240 PM EST WED JAN 2 2008 UPDATED AVIATION DISCUSSION .SYNOPSIS (ISSUED AT 515 AM EST)... 09Z IR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A LARGE TROUGH OVER THE EAST PACIFIC...WITH RIDING OVER THE ROCKY MOUNTAINS. MUCH OF THE EASTERN UNITED STATES IS UNDER THE INFLUENCE OF A TROUGH...WITH AN EMBEDDED 527 DAM UPPER LOW OVER WEST VIRGINIA. AT THE SURFACE...HIGH PRESSURE DOMINATES THE CENTRAL UNITED STATES...WITH LOWS OFF THE NEWFOUNDLAND COAST AND ALEUTIAN ISLANDS. && .DISCUSSION (ISSUED AT 515 AM EST)... MAIN FORECAST CONCERN IS SNOW ACCUMULATION OVER THE NEXT 24 HOURS AND ANY POTENTIAL CHANGE IN HEADLINES. TODAY AND TONIGHT...BY 12Z WINDS SHOULD BE OUT OF THE NORTH-NORTHWEST ACROSS THE CWA...WHICH SHOULD DECREASE SNOW OVER MARQUETTE COUNTY. AT THIS POINT...ADVISORY ENDING AT 12Z THERE SHOULD BE SUFFICIENT. UPPER TROUGH MOVING THROUGH THE CWA WILL PROVIDE SOME SYNOPTIC LIFT DURING THE DAY...WHICH SHOULD TEMPORARILY ENHANCE THE PERSISTENT LES. CONVERGENCE OUT WEST SHOULD DECREASE IN THE EARLY AFTERNOON ONCE THE TROUGH COMES THROUGH...WITH SNOW BEGINNING TO WIND DOWN. 850MB TEMPS AHEAD OF THE TROUGH REMAIN COLD ENOUGH TO SUPPORT LES...AS TEMPS RANGE FROM -15 TO -20C. OVER THE EASTERN PORTION OF THE CWA IN THE AFTERNOON...ADDITIONAL SYNOPTIC LIFT COULD RAMP UP SNOW RATES. DEPENDING ON PHASING OF BEST LOW LEVEL CONVERGENCE AND PASSAGE OF UPPER LEVEL TROUGH...WARNING CRITERIA MIGHT OCCUR. 02/00Z RUN OF THE LOCAL WRF-ARW RUN SHOWS A MAXIMUM OF 0.30 INCHES OF QPF DURING THE 12Z WED-00Z THU TIME PERIOD...WHICH IS VERY SIMILAR TO THE 01/12Z RUN OF THE MODEL. HOWEVER...THIS MODEL SHOWS BETTER PHASING OF UPPER AND LOWER LEVEL FORCING. THE LOCAL WRF-ARW RUN IS FASTER WITH THIS TROUGH PASSAGE THAN THE GFS/NAM/RUC13...WHICH SHOW TROUGH PASSAGE ABOUT 6 HOURS LATER AND AFTER THE TIME OF PEAK LOW LEVEL CONVERGENCE. AS A RESULT...DECIDED NOT TO UPGRADE TO WARNINGS. IF THE TROUGH ENTERS THE AREA MORE QUICKLY...BETTER SNOW RATES MIGHT OCCUR. AS THE SURFACE RIDGE PUSHES THROUGH OVERNIGHT...SNOW SHOULD QUICKLY COME TO AN END AS THE COMBINATION OF DRIER AIR...BACKING WINDS...AND WARMING 850MB TEMPS ENTER THE AREA. THURSDAY THROUGH FRIDAY NIGHT...AREA APPEARS TO DRY OUT A BIT...AND NO SYNOPTIC SYSTEMS ARE PRESENT TO PROVIDE ANY PRECIPITATION. WINDS SHOULD REMAIN OUT OF THE SOUTH-SOUTHWEST DUE TO A RIDGE ACROSS THE EASTERN UNITED STATES...PREVENTING ANY LAKE EFFECT. LOW LEVEL MOISTURE IS SHOWN MOVING INTO THE AREA THURSDAY NIGHT IN BOTH THE NAM AND THE GFS...ALLOWING FOR A POSSIBILITY OF FOG BEFORE DRIER AIR MOVES BACK IN ON FRIDAY. SATURDAY AND SATURDAY NIGHT...A PAIR OF SHORTWAVES MOVE ACROSS UPPER MICHIGAN DURING THE DAY. MID LEVELS ARE QUITE DRY...WITH SATURATION ONLY OCCURRING IN THE LOWEST 3000 FT. CLOUD TOP TEMPERATURES AREN`T ANY HIGHER THAN -5C...AND WITH SURFACE TEMPERATURES BELOW FREEZING IN THE MORNING...GOING P-TYPE OF FREEZING DRIZZLE STILL APPEARS TO BE THE WAY TO GO. GFS SHOWS SURFACE TEMPERATURES FLIRTING WITH FREEZING BY 18Z...BUT WITH HIGHS FORECAST TO TOP OUT AT OR JUST ABOVE FREEZING...FROZEN PRECIPITATION MIGHT PERSIST THROUGHOUT THE DAY. WILL HOLD OFF ON ADDING FREEZING DRIZZLE TO THE AFTERNOON HOURS FOR NOW. WAA CONTINUES INTO SATURDAY NIGHT...WITH THE GFS AND ECMWF BOTH BRINGING SURFACE TEMPERATURES ABOVE FREEZING BY 12Z. UNSETTLED PATTERN PERSISTS INTO EARLY NEXT WEEK...WITH INDICATIONS THAT TEMPERATURES SHOULD ACTUALLY GO ABOVE FREEZING FOR MULTIPLE DAYS. NO CHANGES MADE TO THE FORECAST BEYOND SATURDAY NIGHT. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... AT KCMX...MVFR CONDITIONS IN -SHSN SHOULD PERSIST THRU THE AFTN. THERE STILL MAY BE A FEW BRIEF VIS REDUCTIONS INTO THE IFR RANGE THRU 20Z...BUT AS INCREASINGLY DRIER AIRMASS MOVES INTO THE AREA...-SHSN WILL BECOME LIGHTER AND VIS WILL IMPROVE. BY EVENING...EXPECT MVFR CIGS AND VFR VIS WITH FLURRIES. AS SFC RIDGE MOVES ACROSS THE AREA TONIGHT...WINDS WILL BACK SW...BRINGING AN END TO FLURRIES AND MVFR CLOUDS OFF THE LAKE. GUSTY SW WINDS WILL DEVELOP THU...AND WITH NEW SNOW COVER...SOME BLSN MAY DEVELOP. AT KSAW...CIGS WILL HOVER AROUND 3KFT THRU THE AFTN...AND THERE MAY BE A FEW FLURRIES OFF THE LAKE (NO VIS RESTRICTION). AS SFC RIDGE MOVES ACROSS THE AREA TONIGHT...WINDS WILL BACK SW...BRINGING AN END TO STRATOCU CLOUDS OFF THE LAKE. GUSTY S TO SW WINDS WILL DEVELOP THU...AND WITH NEW SNOW COVER...SOME BLSN MAY DEVELOP. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LOOK FOR WINDS TO 25 KNOTS TO GRADUALLY DIMINISH TO 15 KNOTS OR LESS THIS AFTERNOON INTO THIS EVENING AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. AS THE HIGH SHIFTS EAST ON THURSDAY AND LOW PRESSURE MOVES ACROSS CENTRAL CANADA...GALES ARE EXPECTED ACROSS MOST OF LAKE SUPERIOR. THESE GALES SHOULD DIMINISH WEST TO EAST THURSDAY NIGHT AS THE LOW MOVES INTO NORTHERN QUEBEC. EXPECT WINDS AT OR BELOW 30 KNOTS THROUGH SUNDAY...WITH THE STRONGEST WINDS ON EASTERN LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ007-085. GALE WARNING FROM 7 AM TO 7 PM EST THURSDAY FOR LSZ263-264. GALE WARNING FROM 11 AM TO 8 PM EST THURSDAY FOR LSZ266-267. && $$ SYNOPSIS/DISCUSSION...TAG MARINE...JV AVIATION...ROLFSON mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 721 AM EST WED JAN 2 2008 UPDATED FOR AVIATION DISCUSSION .SYNOPSIS... 09Z IR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A LARGE TROUGH OVER THE EAST PACIFIC...WITH RIDING OVER THE ROCKY MOUNTAINS. MUCH OF THE EASTERN UNITED STATES IS UNDER THE INFLUENCE OF A TROUGH...WITH AN EMBEDDED 527 DAM UPPER LOW OVER WEST VIRGINIA. AT THE SURFACE...HIGH PRESSURE DOMINATES THE CENTRAL UNITED STATES...WITH LOWS OFF THE NEWFOUNDLAND COAST AND ALEUTIAN ISLANDS. && .DISCUSSION... MAIN FORECAST CONCERN IS SNOW ACCUMULATION OVER THE NEXT 24 HOURS AND ANY POTENTIAL CHANGE IN HEADLINES. TODAY AND TONIGHT...BY 12Z WINDS SHOULD BE OUT OF THE NORTH-NORTHWEST ACROSS THE CWA...WHICH SHOULD DECREASE SNOW OVER MARQUETTE COUNTY. AT THIS POINT...ADVISORY ENDING AT 12Z THERE SHOULD BE SUFFICIENT. UPPER TROUGH MOVING THROUGH THE CWA WILL PROVIDE SOME SYNOPTIC LIFT DURING THE DAY...WHICH SHOULD TEMPORARILY ENHANCE THE PERSISTENT LES. CONVERGENCE OUT WEST SHOULD DECREASE IN THE EARLY AFTERNOON ONCE THE TROUGH COMES THROUGH...WITH SNOW BEGINNING TO WIND DOWN. 850MB TEMPS AHEAD OF THE TROUGH REMAIN COLD ENOUGH TO SUPPORT LES...AS TEMPS RANGE FROM -15 TO -20C. OVER THE EASTERN PORTION OF THE CWA IN THE AFTERNOON...ADDITIONAL SYNOPTIC LIFT COULD RAMP UP SNOW RATES. DEPENDING ON PHASING OF BEST LOW LEVEL CONVERGENCE AND PASSAGE OF UPPER LEVEL TROUGH...WARNING CRITERIA MIGHT OCCUR. 02/00Z RUN OF THE LOCAL WRF-ARW RUN SHOWS A MAXIMUM OF 0.30 INCHES OF QPF DURING THE 12Z WED-00Z THU TIME PERIOD...WHICH IS VERY SIMILAR TO THE 01/12Z RUN OF THE MODEL. HOWEVER...THIS MODEL SHOWS BETTER PHASING OF UPPER AND LOWER LEVEL FORCING. THE LOCAL WRF-ARW RUN IS FASTER WITH THIS TROUGH PASSAGE THAN THE GFS/NAM/RUC13...WHICH SHOW TROUGH PASSAGE ABOUT 6 HOURS LATER AND AFTER THE TIME OF PEAK LOW LEVEL CONVERGENCE. AS A RESULT...DECIDED NOT TO UPGRADE TO WARNINGS. IF THE TROUGH ENTERS THE AREA MORE QUICKLY...BETTER SNOW RATES MIGHT OCCUR. AS THE SURFACE RIDGE PUSHES THROUGH OVERNIGHT...SNOW SHOULD QUICKLY COME TO AN END AS THE COMBINATION OF DRIER AIR...BACKING WINDS...AND WARMING 850MB TEMPS ENTER THE AREA. THURSDAY THROUGH FRIDAY NIGHT...AREA APPEARS TO DRY OUT A BIT...AND NO SYNOPTIC SYSTEMS ARE PRESENT TO PROVIDE ANY PRECIPITATION. WINDS SHOULD REMAIN OUT OF THE SOUTH-SOUTHWEST DUE TO A RIDGE ACROSS THE EASTERN UNITED STATES...PREVENTING ANY LAKE EFFECT. LOW LEVEL MOISTURE IS SHOWN MOVING INTO THE AREA THURSDAY NIGHT IN BOTH THE NAM AND THE GFS...ALLOWING FOR A POSSIBILITY OF FOG BEFORE DRIER AIR MOVES BACK IN ON FRIDAY. SATURDAY AND SATURDAY NIGHT...A PAIR OF SHORTWAVES MOVE ACROSS UPPER MICHIGAN DURING THE DAY. MID LEVELS ARE QUITE DRY...WITH SATURATION ONLY OCCURRING IN THE LOWEST 3000 FT. CLOUD TOP TEMPERATURES AREN`T ANY HIGHER THAN -5C...AND WITH SURFACE TEMPERATURES BELOW FREEZING IN THE MORNING...GOING P-TYPE OF FREEZING DRIZZLE STILL APPEARS TO BE THE WAY TO GO. GFS SHOWS SURFACE TEMPERATURES FLIRTING WITH FREEZING BY 18Z...BUT WITH HIGHS FORECAST TO TOP OUT AT OR JUST ABOVE FREEZING...FROZEN PRECIPITATION MIGHT PERSIST THROUGHOUT THE DAY. WILL HOLD OFF ON ADDING FREEZING DRIZZLE TO THE AFTERNOON HOURS FOR NOW. WAA CONTINUES INTO SATURDAY NIGHT...WITH THE GFS AND ECMWF BOTH BRINGING SURFACE TEMPERATURES ABOVE FREEZING BY 12Z. UNSETTLED PATTERN PERSISTS INTO EARLY NEXT WEEK...WITH INDICATIONS THAT TEMPERATURES SHOULD ACTUALLY GO ABOVE FREEZING FOR MULTIPLE DAYS. NO CHANGES MADE TO THE FORECAST BEYOND SATURDAY NIGHT. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... AT KSAW...HEAVIER LES BANDS GRADUALLY SHIFTING EASTWARD THIS MORNING WITH BACKING FLOW. LOOK FOR PREVAILING MVFR/TEMPO IFR VSBYS TO IMPROVE TO VFR BY 15Z. FLOW BACKING TO LIGHT W-SW DIRECTION THIS EVENING WILL CAUSE MVFR CIGS TO BREAK APART WITH INCREASING DRYING/SUBSIDENCE FROM THE WEST. AT KCMX...PREVAILING MVFR/TEMPO IFR VSBYS IN SNOW THIS MORNING SHOULD IMPROVE TO VFR BY EARLY AFTERNOON WITH INCREASING DRYING/SUBSIDENCE. LOOK FOR FLURRIES TO END AND MVFR CIGS BREAK APART BY LATE EVENING AS WEAKENING FLOW BACKS SW WITH THE APPROACH OF SFC RIDGE AXIS FROM THE WEST. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LOOK FOR WINDS TO 25 KNOTS TO GRADUALLY DIMINISH TO 15 KNOTS OR LESS THIS AFTERNOON INTO THIS EVENING AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. AS THE HIGH SHIFTS EAST ON THURSDAY AND LOW PRESSURE MOVES ACROSS CENTRAL CANADA...GALES ARE EXPECTED ACROSS MOST OF LAKE SUPERIOR. THESE GALES SHOULD DIMINISH WEST TO EAST THURSDAY NIGHT AS THE LOW MOVES INTO NORTHERN QUEBEC. EXPECT WINDS AT OR BELOW 30 KNOTS THROUGH SUNDAY...WITH THE STRONGEST WINDS ON EASTERN LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ005. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ007-085. GALE WARNING FROM 7 AM TO 7PM EST THURSDAY FOR LSZ263-264. GALE WARNING FROM 11 AM TO 8 PM EST THURSDAY FOR LSZ266-267. && $$ SYNOPSIS/DISCUSSION...TAG MARINE...JV AVIATION...JV mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 515 AM EST WED JAN 2 2008 .SYNOPSIS... 09Z IR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A LARGE TROUGH OVER THE EAST PACIFIC...WITH RIDING OVER THE ROCKY MOUNTAINS. MUCH OF THE EASTERN UNITED STATES IS UNDER THE INFLUENCE OF A TROUGH...WITH AN EMBEDDED 527 DAM UPPER LOW OVER WEST VIRGINIA. AT THE SURFACE...HIGH PRESSURE DOMINATES THE CENTRAL UNITED STATES...WITH LOWS OFF THE NEWFOUNDLAND COAST AND ALEUTIAN ISLANDS. && .DISCUSSION... MAIN FORECAST CONCERN IS SNOW ACCUMULATION OVER THE NEXT 24 HOURS AND ANY POTENTIAL CHANGE IN HEADLINES. TODAY AND TONIGHT...BY 12Z WINDS SHOULD BE OUT OF THE NORTH-NORTHWEST ACROSS THE CWA...WHICH SHOULD DECREASE SNOW OVER MARQUETTE COUNTY. AT THIS POINT...ADVISORY ENDING AT 12Z THERE SHOULD BE SUFFICIENT. UPPER TROUGH MOVING THROUGH THE CWA WILL PROVIDE SOME SYNOPTIC LIFT DURING THE DAY...WHICH SHOULD TEMPORARILY ENHANCE THE PERSISTENT LES. CONVERGENCE OUT WEST SHOULD DECREASE IN THE EARLY AFTERNOON ONCE THE TROUGH COMES THROUGH...WITH SNOW BEGINNING TO WIND DOWN. 850MB TEMPS AHEAD OF THE TROUGH REMAIN COLD ENOUGH TO SUPPORT LES...AS TEMPS RANGE FROM -15 TO -20C. OVER THE EASTERN PORTION OF THE CWA IN THE AFTERNOON...ADDITIONAL SYNOPTIC LIFT COULD RAMP UP SNOW RATES. DEPENDING ON PHASING OF BEST LOW LEVEL CONVERGENCE AND PASSAGE OF UPPER LEVEL TROUGH...WARNING CRITERIA MIGHT OCCUR. 02/00Z RUN OF THE LOCAL WRF-ARW RUN SHOWS A MAXIMUM OF 0.30 INCHES OF QPF DURING THE 12Z WED-00Z THU TIME PERIOD...WHICH IS VERY SIMILAR TO THE 01/12Z RUN OF THE MODEL. HOWEVER...THIS MODEL SHOWS BETTER PHASING OF UPPER AND LOWER LEVEL FORCING. THE LOCAL WRF-ARW RUN IS FASTER WITH THIS TROUGH PASSAGE THAN THE GFS/NAM/RUC13...WHICH SHOW TROUGH PASSAGE ABOUT 6 HOURS LATER AND AFTER THE TIME OF PEAK LOW LEVEL CONVERGENCE. AS A RESULT...DECIDED NOT TO UPGRADE TO WARNINGS. IF THE TROUGH ENTERS THE AREA MORE QUICKLY...BETTER SNOW RATES MIGHT OCCUR. AS THE SURFACE RIDGE PUSHES THROUGH OVERNIGHT...SNOW SHOULD QUICKLY COME TO AN END AS THE COMBINATION OF DRIER AIR...BACKING WINDS...AND WARMING 850MB TEMPS ENTER THE AREA. THURSDAY THROUGH FRIDAY NIGHT...AREA APPEARS TO DRY OUT A BIT...AND NO SYNOPTIC SYSTEMS ARE PRESENT TO PROVIDE ANY PRECIPITATION. WINDS SHOULD REMAIN OUT OF THE SOUTH-SOUTHWEST DUE TO A RIDGE ACROSS THE EASTERN UNITED STATES...PREVENTING ANY LAKE EFFECT. LOW LEVEL MOISTURE IS SHOWN MOVING INTO THE AREA THURSDAY NIGHT IN BOTH THE NAM AND THE GFS...ALLOWING FOR A POSSIBILITY OF FOG BEFORE DRIER AIR MOVES BACK IN ON FRIDAY. SATURDAY AND SATURDAY NIGHT...A PAIR OF SHORTWAVES MOVE ACROSS UPPER MICHIGAN DURING THE DAY. MID LEVELS ARE QUITE DRY...WITH SATURATION ONLY OCCURRING IN THE LOWEST 3000 FT. CLOUD TOP TEMPERATURES AREN`T ANY HIGHER THAN -5C...AND WITH SURFACE TEMPERATURES BELOW FREEZING IN THE MORNING...GOING P-TYPE OF FREEZING DRIZZLE STILL APPEARS TO BE THE WAY TO GO. GFS SHOWS SURFACE TEMPERATURES FLIRTING WITH FREEZING BY 18Z...BUT WITH HIGHS FORECAST TO TOP OUT AT OR JUST ABOVE FREEZING...FROZEN PRECIPITATION MIGHT PERSIST THROUGHOUT THE DAY. WILL HOLD OFF ON ADDING FREEZING DRIZZLE TO THE AFTERNOON HOURS FOR NOW. WAA CONTINUES INTO SATURDAY NIGHT...WITH THE GFS AND ECMWF BOTH BRINGING SURFACE TEMPERATURES ABOVE FREEZING BY 12Z. UNSETTLED PATTERN PERSISTS INTO EARLY NEXT WEEK...WITH INDICATIONS THAT TEMPERATURES SHOULD ACTUALLY GO ABOVE FREEZING FOR MULTIPLE DAYS. NO CHANGES MADE TO THE FORECAST BEYOND SATURDAY NIGHT. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... TAF FORECASTS WILL CONTINUE TO BE ABOUT LAKE EFFECT UNTIL LATE IN THE AFTERNOON TO EARLY EVENING. CONDITIONS WILL BE MVFR FOR THE MOST PART WITH IFR IN THE HEAVIER LAKE EFFECT BANDS FOR VISIBILITIES. CIGS SHOULD STAY IN THE MVFR RANGE. WINDS ARE PROGGED TO SWITCH NW LATE TONIGHT INTO WED...WHICH WILL ALLOW KSAW TO IMPROVE. DRY AIR WILL MOVE IN LATE IN THE AFTERNOON AT BOTH SITES. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LOOK FOR WINDS TO 25 KNOTS TO GRADUALLY DIMINISH TO 15 KNOTS OR LESS THIS AFTERNOON INTO THIS EVENING AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. AS THE HIGH SHIFTS EAST ON THURSDAY AND LOW PRESSURE MOVES ACROSS CENTRAL CANADA...GALES ARE EXPECTED ACROSS MOST OF LAKE SUPERIOR. THESE GALES SHOULD DIMINISH WEST TO EAST THURSDAY NIGHT AS THE LOW MOVES INTO NORTHERN QUEBEC. EXPECT WINDS AT OR BELOW 30 KNOTS THROUGH SUNDAY...WITH THE STRONGEST WINDS ON EASTERN LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ005. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ007-085. GALE WARNING FROM 7 AM TO 7PM EST THURSDAY FOR LSZ263-264. GALE WARNING FROM 11 AM TO 8 PM EST THURSDAY FOR LSZ266-267. && $$ SYNOPSIS/DISCUSSION...TAG MARINE...JV AVIATION...MICHELS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 641 PM EST TUE JAN 1 2008 .SYNOPSIS... 21Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A LARGE TROUGH OVER THE EAST PACIFIC...STRONG RIDGING DEVELOPING AHEAD OF IT OVER WESTERN NORTH AMERICA...AND TROUGHING ACROSS THE REST OF NORTH AMERICA. BETWEEN THE WESTERN RIDGE AND EASTERN TROUGH...A BROAD 120-140 KT JET EXISTS NEAR 200MB FROM SASKATCHEWAN INTO OKLAHOMA. WITHIN THE TROUGH...THE MAIN FEATURES TO NOTE ARE A 525 DAM LOW IN NW ILLINOIS...A VERY WEAK RIDGE OVER NW ONTARIO...AND A SHRTWV DROPPING SOUTH THROUGH MANITOBA. RELATIVELY CHILLY 850MB TEMPS HAVE MOVED INTO THE AREA ASSOCIATED WITH THE UPPER LOW TO OUR SW...WITH READINGS AT 12Z OF -14C AT GRB...-17C AT MPX AND -19C AT INL. THESE COOLER 850MB TEMPS...ALONG WITH ADVECTION OF MOISTURE OF THE INL SOUNDING...ARE HELPING TO PRODUCE LAKE EFFECT SNOW SHOWERS ACROSS LAKE SUPERIOR. ORIENTATION OF THE LAKE EFFECT THROUGH THE MUCH OF THE DAY HAS BEEN NW TO SE...DUE TO THE CWA BEING ON THE SOUTH SIDE OF A TROUGH OVER EASTERN LAKE SUPERIOR. THIS LONGER PERIOD OF SUSTAINED NW WINDS HAD RESULTED IN 6 INCHES OF SNOW IN ROCKLAND BETWEEN 9 AM AND 1230 PM...PRIMARILY DUE TO A DOMINANT BAND THAT DEVELOPED. HOWEVER...THIS TROUGH IS FINALLY DROPPING SOUTH...WITH NE WINDS DEVELOPING BEHIND IT OVER THE KEWEENAW AND EASTERN LAKE SUPERIOR. ALONG THIS CONVERGENCE ZONE IS A BAND OF MODERATE TO HEAVY SNOWFALL ON RADAR...WHICH BROUGHT VSBYS DOWN TO 1/4SM OR LESS AT MOHAWK PER SPOTTER REPORT. ISSUED AN SPS FOR MARQUETTE AND ALGER COUNTIES TO ALERT ABOUT THIS BAND. COLDER AIR EXISTS UPSTREAM UNDER THE SHRTWV DROPPING SOUTH ACROSS MANITOBA...NOTED BY SURFACE TEMPS STRUGGLING TO GET MUCH ABOVE ZERO. SOME MOISTURE IS ALSO PRESENT WITH THIS SHRTWV WITH LIGHT SNOW REPORTS. BEHIND THIS SHRTWV...A LARGE AREA OF STRONG HIGH PRESSURE EXTENDS FROM THE ROCKIES INTO SASKATCHEWAN. && .SHORT TERM (TONIGHT THROUGH WED)... TONIGHT...SHRTWV OVER MANITOBA WILL DROP SE INTO IOWA BY 12Z... HOWEVER THE GENERAL TROUGHING ASSOCIATED WITH IT SHOULD MOVE INTO WESTERN LAKE SUPERIOR LATE TONIGHT. THIS WILL ALLOW THE WEAK RIDGE TO MOVE OVER LAKE SUPERIOR...CAUSING PRESSURE RISES AT THE SURFACE OVER NE ONTARIO...AND THUS A CONTINUED FORCING MECHANISM TO KEEP THE TROUGH OVER LAKE SUPERIOR DROPPING SOUTH. NORTH TO NORTHEAST WINDS BEHIND THE TROUGH WILL FAVOR BANDS INTO THE FAR WEST AND NORTH CENTRAL U.P....WHERE HEADLINES ARE UP. SOME DRY AIR ENTERING THE PICTURE AFTER MIDNIGHT...ALONG WITH SUBSIDENCE FROM THE WEAK UPPER RIDGE...SHOULD CAUSE THE LAKE EFFECT TO DIMINISH SOME. THIS IS REFLECTED WELL IN MODEL QPFS AND THE FORECAST. THE DRY AIR WILL BE TEMPORARY...WITH THE APPROACH OF THE UPPER TROUGHING LATE. THIS UPPER TROUGH SHOULD CAUSE WINDS TO BACK NW...FAVORING SOME LIGHT SNOW SHOWERS OVER THE KEWEENAW AND EVENTUALLY AREAS EAST OF MUNISING. HOWEVER...THE NW WIND IS NOT GOOD FOR MARQUETTE COUNTY... AND THUS THE GOING ADVISORY END TIME OF 12Z WED STILL LOOKS GOOD. NORTHERLY FLOW OVER THE CWA SHOULD KEEP BOTH CLOUDS AND WARMER LAKE SUPERIOR AIR FLOWING ACROSS. THE COLDEST SPOT SHOULD BE OUT IN IWD WHERE NW WINDS DEVELOPING AFTER MIDNIGHT DRAG IN COLDER AIR FROM WI. WEDNESDAY...THE UPPER TROUGH WILL MOVE THROUGH THE CWA DURING THE DAY...WITH FAIRLY IMPRESSIVE HEIGHT RISES DEVELOPING AFTER 18Z. THESE HEIGHT RISES WILL BE ACCOMPANIED BY DRY AIR AND SUBSIDENCE. HOWEVER...UNTIL THE HEIGHT RISES OCCUR...NW WINDS WITH LAKE EFFECT SNOW ARE EXPECTED. MOST OF THE MODELS HAVE A NW TO SE TROUGH ORIENTED AGAIN FROM THE TIP OF THE KEWEENAW INTO THE EASTERN CWA DURING THE DAY. THE LOCAL WRF-ARW ACTUALLY DEVELOPS FAIRLY STRONG CONVERGENCE ALONG THIS TROUGH INTO LUCE COUNTY...WHICH WOULD RESULT IN SOME DECENT QPF. ALSO...WITH COLDER 850MB AIR MOVING IN ON THE ORDER OF -18 TO -20C WITH THE TROUGH AND NOT TO STRONG OF WINDS...30 TO 1 SNOWFALL RATIOS ARE LIKELY. IF THE LOCAL WRF-ARW RUN IS CORRECT...WE COULD BE DEALING WITH WARNING CRITERIA FOR LUCE COUNTY. HOWEVER...FEEL IT IS PROBABLY OVERDONE...AND WITH SOME UNCERTAINTY REGARDING THE TROUGH PLACEMENT...HAVE CUT THE AMOUNTS BACK. STILL... FIGURED AN ADVISORY FOR ALGER...LUCE AND NORTHERN SCHOOLCRAFT COUNTIES IS WARRANTED. SNOW SHOULD DIMINISH IN THE AFTERNOON EVERYWHERE AS THE SUBSIDENCE AND DRY AIR MOVE IN. TEMPS WILL BE CHILLY GIVEN THE COLD 850MB READINGS MENTIONED EARLY. GOING FORECAST TEMPS SEEMED REASONABLE...WITH THE WARMEST READINGS ALONG LAKE MI WHERE NW WINDS DOWNSLOPE...AND ALONG THE EASTERN U.P. SHORELINE WITH THE MARINE INFLUENCE. && .LONG TERM (WEDNESDAY NIGHT THROUGH NEXT TUESDAY)... WED NIGHT...850 MB TEMPS WILL BE AROUND -18C EARLY IN THE NIGHT TO SUPPORT RESIDUAL LES FOR NW WIND FAVORED AREAS...BUT TAPER OFF BY EARLY MORNING AS WINDS BACK AND BECOME SOUTHERLY. MAY NEED TO CUT BACK GOING POPS FOR LATE WED NIGHT IN NEXT FORECAST UPDATE. WITH COLD AIR MASS STILL IN PLACE...LITTLE MOISTURE AVAILABLE...AND DECOUPLED WINDS BEFORE THE STRONGER SW FLOW GETS HERE LATE WILL ALLOW TEMPS TO FALL BELOW ZERO ACROSS INLAND WEST AREAS OVERNIGHT. THU...DESPITE STRONG WAA AND WSW 850MB WINDS TO 60 KT...MODELS STILL INDICATE VERY DRY AIR AT ALL LEVELS...SO CONTINUED NO PCPN CHANCE THU THROUGH FRI. HOWEVER...GFS AND ECMWF BOTH SHOW SHALLOW MOISTURE FROM 00Z FRI ONWARD. KEPT WITH DRY FCST AND 60 PERCENT CLOUD COVER...BUT WOULDN`T BE SURPRISED IF THERE WILL BE FOG...DRIZZLE OR LOW CLOUDS TO CONTEND WITH. THU THROUGH SAT...STRONG WAA WSW FLOW TAKES OVER AS A MID LEVEL TROUGH MOVES INTO THE WRN CONUS AND A BROAD/FLAT RIDGE EXPANDS INTO THE PLAINS AND GREAT LAKES. MDLS MOISTURE FIELDS SUGGEST THAT THE AIRMASS WILL REMAIN TO DRY TO SUPPORT MEASURABLE PCPN. ON A SIMILAR NOTE...I REMOVED PCPN CHANCE (SCHC -SN -ZR) FOR 00Z-12Z SAT. THERE COULD BE A CHANCE FOR SOME SORT OF DRIZZLE OR FREEZING DRIZZLE WITH THE MILD TEMPS (> -10C)...BUT SINCE OMEGA VALUES ARE SO HIGH AND MOISTURE IS VERY SHALLOW...RULED OUT CHANCE OF RAIN. THE BETTER FORCING COMES ALONG WITH A SHORTWAVE AFTER 12Z SAT. DUE TO A PERSISTENT 850-700 DRY LAYER...KEPT SCHC ZL FOR SAT MORNING BEFORE CHANGING IT OVER TO SCHC -RA IN THE AFTERNOON AS GREATER FORCING AND MORE MOISTURE BECOMES AVAILABLE. THE MORNING ZL MAY NEED TO BE CHANGED TO L IN A FCST UPDATE...BUT FOR NOW...EXPECTING THE TEMPS TO BE LOW ENOUGH IN THE MORNING TO SUPPORT THE ZL. SAT NIGHT THROUGH TUE...MODELS IN GENERAL AGREEMENT THAT THERE WILL BE A BROADSCALE TROUGH ACROSS THE WESTERN CONUS AND RIDGE IN THE EAST. SEVERAL SHORTWAVES WILL FORM ALONG THE INFLECTION. THE TIMING...STRENGTH AND LOCATION OF THE SHORTWAVES ARE DEBATABLE. THE GFS 12Z MODEL CAME IN WITH A DEEP...CLOSED LOW OVER THE NORTHERN PLAINS ON MON. MOST CANADIAN HINTS AT A CLOSED LOW BUT IT IS MUCH WEAKER. ECMWF SHOWS A WEAK SHORTWAVE IN THE UPPER GREAT LAKES FOR THE SUNDAY TIME PERIOD. KEPT CHC RAIN GOING FOR SAT NIGHT THROUGH TUE MORNING. INCREASED POPS MON AFTERNOON AND EVE...ESPECIALLY OVER THE WEST TO ACCOUNT FOR MODEL AGREEMENT OF SOME GENERAL PRECIP EVENT. WET BULB ZERO HEIGHTS GREATER THAN 1500 SUPPORT RAIN THROUGH THIS TIME PERIOD. OVERNIGHT LOWS BARELY DROP TO FREEZING EACH NIGHT. SOME OF THE MODEL SOLUTIONS EVEN SUGGEST POTENTIAL FOR TSTMS WITH A STRONG SRLY LOW LEVEL JET AND SHOWALTER VALUES AROUND -1 OVER THE SOUTH AND WEST...AND 850 MB DEWPOINTS NEAR 8C. THE COLD FRONT WILL ENTER THE CWA FROM WEST TO EAST ON TUE. TIMING IS UNCERTAIN...OF COURSE...SO INTRODUCED A TREND OF RAIN CHANGING OVER TO SNOW FROM WEST TO EAST DURING THE DAY AND BECOMING ALL SNOW OVERNIGHT. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... TAF FORECASTS ARE ALL ABOUT LAKE EFFECT TRENDS FOR THE NEXT 24 HOURS. CONDITIONS WILL BE MVFR FOR THE MOST PART WITH IFR IN THE HEAVIER LAKE EFFECT BANDS FOR VISIBILITIES. CIGS SHOULD STAY IN THE MVFR RANGE. WINDS ARE PROGGED TO SWITCH NW LATE TONIGHT INTO WED...WHICH WILL FAVOR KCMX DROPPING BACK DOWN TO IFR VSBYS AGAIN...AND ALLOW KSAW TO CLIMB BACK UP. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... SURFACE TROUGH FROM THE KEWEENAW PENINSULA INTO LUCE COUNTY WILL DROP SOUTH THIS EVENING. WINDS OF 30 KT ARE POSSIBLE BEHIND IT...WHICH COMBINED WITH COLD AIR FLOWING OFF THE MN ARROWHEAD COULD HELP SUPPORT HEAVY FREEZING SPRAY OVER FAR WESTERN LAKE SUPERIOR INTO WEDNESDAY MORNING. LOOK FOR WINDS TO GRADUALLY DIMINISH THROUGH THE DAY WEDNESDAY AND INTO WEDNESDAY NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. AS THE HIGH SHIFTS TO THE EAST ON THURSDAY AND LOW PRESSURE MOVES ACROSS CENTRAL CANADA...GALES ARE LIKELY ON ALL OF LAKE SUPERIOR. THESE GALES SHOULD DIMINISH WEST TO EAST THURSDAY NIGHT AS THE LOW MOVES INTO NORTHERN QUEBEC. EXPECT WINDS AT OR BELOW 30 KNOTS THROUGH SUNDAY...WITH THE STRONG WINDS ON EASTERN LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT CST / 1 AM EST WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ005. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 PM EST WEDNESDAY FOR MIZ006. LAKE EFFECT SNOW ADVISORY FROM 7 AM EST TO 7 PM EST WEDNESDAY FOR MIZ007-085. HEAVY FREEZING SPRAY WARNING IN EFFECT UNTIL NOON CST WEDNESDAY FOR LSZ162. && $$ SYNOPSIS/SHORT TERM/MARINE...AJ LONG TERM...MRC AVIATION...AJ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1255 PM EST TUE JAN 1 2008 UPDATED AVIATION SECTION FOR 18Z TAF ISSUANCE...AND THE UPDATE SECTION ABOUT AN UPGRADED HAZARD. .UPDATE... MADE A QUICK CALL OUT TO ROCKLAND AND ONTONAGON IN ONTONAGON COUNTY TO SEE HOW MUCH SNOW HAS OCCURRED WITH THE BAND THAT HAS REMAINED NEARLY STATIONARY SINCE EARLIER THIS MORNING. SINCE 9 AM...ONTONAGON HAS ONLY PICKED UP AN INCH OR TWO...BUT THE HIGHER ELEVATION OF ROCKLAND HAS RESULTED IN 6 INCHES THERE. SINCE THE LATEST RUC 13 FROM NCEP DEPICTS THE BAND NOT MOVING SOUTH UNTIL 21 OR 22Z...GIVEN THE SLOW DROPPING SOUTH MOTION OF THE TROUGH OVER EASTERN LAKE SUPERIOR...THE ROCKLAND AND MASS CITY AREAS WILL REACH WARNING CRITERIA. THUS...HAVE UPGRADED ONTONAGON COUNTY TO A WARNING. PREVIOUS UPDATE ISSUED AT 1151 AM... MAIN ISSUE WITH THE FORECAST HAS BEEN LAKE EFFECT TRENDS...WHICH HAVE BEEN GOING A BIT SLOWER THAN PREVIOUSLY PLANNED. SURFACE ANALYSIS DEPICTS A TROUGH EXTENDING FROM JUST OFF THE TIP OF THE KEWEENAW TO IN-BETWEEN MUNISING AND GRAND MARAIS...AND THEN SE INTO NORTHERN LOWER MI. NORTHWEST WINDS ON THE WEST SIDE OF THIS TROUGH HAVE BEEN BRINGING LAKE EFFECT SNOW SHOWERS FROM IWD UP THROUGH THE KEWEENAW AS SEEN ON VISIBLE SATELLITE IMAGERY. HOWEVER...FLOW AS BEEN BACKING A LITTLE MORE WESTERLY OVER NORTHERN WI INTO THE WI BORDER COUNTIES...AND THIS HAS CAUSED DRIER AIR TO MOVE IN AND NOW THE SNOW IS DIMINISHING IN IWD. 12Z SOUNDING FROM GRB AND 14Z TAMDAR SOUNDING FROM RHI DEPICT THIS DRY AIR BY ONLY HAVING A THIN SATURATED LAYER AROUND 850MB. AROUND THE TROUGH...A MESO-LOW CAN BE SEEN OFF THE TIP OF THE KEWEENAW...WHICH IS GRADUALLY DROPPING SOUTH TOWARDS MARQUETTE COUNTY. NORTHEAST ORIENTED BANDS CAN BE SEEN FORMING BEHIND THE MESO-LOW. THE TIMING OF THE TROUGH DROPPING SOUTH IS CRITICAL TO THE FORECAST...AS THE LONGER THE NORTHWEST WINDS STICK AROUND...THE GREATER POTENTIAL ONTONAGON COUNTY HAS OF REACHING WARNING AND LESSER POTENTIAL FOR GOGEBIC COUNTY TO REACH WARNING. THE 12Z CANADIAN FROM YESTERDAY WAS FIRST TO PRESENT THIS IDEA OF A SLOWER TROUGH PASSAGE...AND THIS SEEMS TO BE PANNING OUT. THEREFORE HAVE INCREASED AMOUNTS A BIT IN ONTONAGON COUNTY...BUT KEPT THEM BELOW WARNING...SINCE ONCE THE TROUGH PASSES THIS AFTERNOON THE CONVERGENCE WEAKENS THERE. THE KEWEENAW STILL LOOKS FINE NOT IN ADVISORY AS WINDS WILL BE SHIFTING TO THE NNE SOON...WHICH IS A GENERAL BAD WIND DIRECTION THERE FOR LAKE EFFECT. DELAYED TIMING OF THE SNOW INTO THE NORTH CENTRAL U.P. WITH THE SLOWER TROUGH PASSAGE. HOWEVER...GIVEN THE PRESENCE OF A MESO-LOW...EXPECT SOME HEAVY SNOWFALL RATES ONCE THE TROUGH MOVES IN LATE TODAY (PER MOVEMENT EXTRAPOLATION). FARTHER EAST...WAS TEMPTED TO HOIST AN ADVISORY FOR LUCE COUNTY WITH A BAND ON THE EAST SIDE OF THE TROUGH THAT HAS REMAINED GENERALLY STATIONARY THROUGH MUCH OF THE MORNING. HOWEVER...WITH CONVERGENCE WEAKENING A LOT THIS AFTERNOON... ESPECIALLY WHEN WINDS TURN NE LATE...ADDITIONAL ACCUMULATIONS SHOULD BE ON THE LIGHT SIDE. DIMINISHED CLOUD COVER AND PCPN IN THE SOUTH CENTRAL U.P. WITH WNW WINDS HOLDING DRY AIR IN THERE. CLOUD COVER AND SNOW SHOULD PICK UP LATE IN DICKINSON/IRON WHEN THE TROUGH MOVES IN. NO CHANGES MADE TO THE TONIGHT FORECAST. && .SYNOPSIS... IR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOW AN UPPER LEVEL LOW DRIFTING SLOWLY SOUTH INTO NORTHERN MINNESOTA...WITH A BROAD TROUGH ACROSS THE CENTRAL UNITED STATES. A POTENT SHORTWAVE MOVING INTO LOWER MICHIGAN IS TOUCHING OFF PRECIPITATION ACROSS THE NORTHERN OHIO RIVER VALLEY. A BROAD RIDGE IS PUSHING ONSHORE ALONG THE WEST COAST. AT THE SURFACE...LOW PRESSURE IS DEEPENING ACROSS THE OHIO RIVER VALLEY. HIGH PRESSURE REMAINS NEARLY STATIONARY ALONG THE LENGTH OF THE ROCKY MOUNTAINS. && .DISCUSSION... TODAY AND TONIGHT...MODELS SHOW VERY GOOD AGREEMENT WITH A CONVERGENCE AREA ALREADY PRESENT AT 12Z ALONG THE WESTERN LAKE SUPERIOR SHORELINE. CONVERGENCE LOOKS TO BE FOCUSED THE BEST IN GOGEBIC AND ONTONAGON COUNTIES...WHICH IS ALSO REFLECTED BY THE WARNING IN EFFECT FOR GOGEBIC COUNTY. NAM AND LOCAL HI-RES WRF-ARW MODEL BOTH SHOW THE FAVORED CONVERGENCE ZONE MOVING OUT OF ONTONAGON COUNTY AND INTO GOGEBIC COUNTY BETWEEN 12Z AND 18Z. AM SOMEWHAT CONCERNED THAT AN ISOLATED LOCATION IN WESTERN ONTONAGON COUNTY MIGHT SEE WARNING CRITERIA...BUT HAVE DECIDED TO NOT UPGRADE THAT COUNTY. CONVERGENCE BEGINS TO DIMINISH LATE IN THE AFTERNOON AT THE SAME TIME THAT OMEGA VALUES BEGIN TO DECREASE. WINDS WILL STILL REMAIN FAVORABLE FOR CONTINUED LES AT REDUCED RATES...AND INVERSION HEIGHTS WILL BECOME TO COME DOWN AFTER MIDNIGHT. HEADLINES EXPIRING AT 06Z WEDNESDAY LOOKS FINE. MODELS SHOW A SECOND MAJOR AREA OF 950MB CONVERGENCE DEVELOPING ALONG THE MARQUETTE AND ALGER COUNTY SHORELINES IN THE LATE MORNING AND EARLY AFTERNOON HOURS. ALTHOUGH GREATEST VERTICAL MOTION WILL BE JUST BELOW THE DENDRITIC GROWTH ZONE...WINDS VEERING FROM NORTHWEST TO NORTH IN THE AFTERNOON WILL PROVIDE MAXIMUM FETCH OVER LAKE SUPERIOR AND BEST CHANCES FOR HIGH SNOWFALL RATES IN MARQUETTE COUNTY. OVERNIGHT WINDS BACK TO THE NORTHWEST AGAIN...SHIFTING AREAS OF BEST CONVERGENCE EAST INTO ALGER COUNTY. WINDS SHOULD REMAIN FAIRLY GUSTY DURING THIS TIME PERIOD...WHICH SHOULD RESULT IN BLOWING SNOW...ESPECIALLY NEAR THE SHORELINE. IN ADDITION...HIGHER WIND SPEEDS SHOULD HELP A BIT WITH COMPACTION OF SNOWPACK...AND SHOULD PREVENT SNOW-LIQUID RATIOS FROM CREEPING INTO THE 30:1 RANGE. PREVIOUS FORECAST USED RATIOS OF 25:1...AND WILL CONTINUE THAT IN THIS FORECAST. OVERALL...SNOW ACCUMULATIONS IN THIS TIME PERIOD WERE ONLY SLIGHTLY MODIFIED. WEDNESDAY...AS WINDS SHIFT MORE TO A WEST-NORTHWEST DIRECTION...SNOWFALL SHOULD BEGIN TO TAPER OFF ALONG THE WESTERN LAKE SUPERIOR SHORELINE AS A RESULT OF THE SHORTER FETCH. CONDITIONS LOOK FAVORABLE FOR ALGER COUNTY TO PICK UP ADDITIONAL SNOWFALL...WITH ACCUMULATIONS OF TWO TO FOUR INCHES DURING THE DAY...SLIGHTLY HIGHER THAN THE PREVIOUS FORECAST. LATER SHIFTS MAY NEED TO DETERMINE WHETHER THE ADVISORY IN ALGER COUNTY WOULD NEED TO BE EXTENDED LONGER THAN 12Z...ALTHOUGH THIS ENDING TIME APPEARS TO BE SUFFICIENT FOR MARQUETTE COUNTY. WEDNESDAY NIGHT THROUGH FRIDAY...MODELS APPEAR TO BE SLIGHTLY SLOWER WITH MOVING THE RIDGE INTO THE AREA...AND THEREFORE LES MIGHT PERSIST INTO WEDNESDAY EVENING. WITH CLOUDS TAKING LONGER TO MOVE OUT OF THE AREA...LOW TEMPERATURES MIGHT NOT BOTTOM OUT QUITE AS MUCH AS PREVIOUSLY EXPECTED. A WEAK TROUGH MOVES THROUGH THE AREA ON THURSDAY AFTERNOON...BUT WITH A LACK OF MOISTURE PRECIPITATION DOES NOT APPEAR TO BE LIKELY. FRIDAY NIGHT...GOING FORECAST FOR SLIGHT POPS OF FREEZING DRIZZLE AND/OR SNOW STILL LOOKS ON TARGET. SOUNDINGS SHOW DRY MID LEVELS WITH SHALLOW NEAR-SURFACE SATURATED LAYER. WITH CLOUD TOPS NO HIGHER THAN ABOUT -5C...FROZEN PRECIPITATION LOOKS LIKE IT WOULD HAVE A BETTER CHANCE OF OCCURRING. HOWEVER...GFS ONLY HAS ONE OR TWO HUNDREDTHS OF PRECIP AT THAT TIME...WITH THE ECMWF ONLY PUTTING PRECIP OUT OVER THE WESTERN HALF OF UPPER MICHIGAN. AT THIS POINT...SEE NO NEED TO MAKE ANY CHANGES. NO CHANGES MADE TO THE FORECAST BEYOND FRIDAY NIGHT. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... TAF FORECASTS ARE ALL ABOUT LAKE EFFECT TRENDS FOR THE NEXT 24 HOURS...AND AT LEAST IN THE VERY SHORT TERM ARE DEPENDENT ON THE TIMING OF A TROUGH AT 1730Z FROM THE KEWEENAW INTO ALGER COUNTY DROPPING SOUTH. ALONG THIS TROUGH...A BAND OF HEAVY SNOW IS INDICATED ON SATELLITE AND RADAR IMAGERY. EXTRAPOLATION OF THIS TROUGH WOULD BRING IT TO CMX AROUND 19Z AND SAW AROUND 00Z. BEFORE THE TROUGH ARRIVES...NW ORIENTED LAKE EFFECT CLOUDS/SNOW SHOWER BANDS WILL CONTINUE TO IMPACT BOTH SITES...WITH CMX EXPERIENCING THE LOWEST VSBYS BECAUSE OF THEIR CLOSER PROXIMITY. NW WINDS DOWNSLOPE AT SAW...SO MVFR VSBYS ARE THE WORST EXPECTED...AND MAY STAY VFR FOR VSBY THROUGH MUCH OF THE AFTERNOON. WHEN THE TROUGH MOVES IN...VSBY WILL LIKELY DROP RAPIDLY...AND INDICATED THIS IN THE TAFS BY EITHER LIFR OR VLIFR VSBYS...ALONG WITH AN IFR OR LIFR CIG. IN THE WAKE OF THE TROUGH...WINDS TURN NNE FOR MUCH OF THE OVERNIGHT...WHICH FAVORS SAW TO EXPERIENCE LOWER VSBYS...LIKELY IFR. WINDS ARE PROGGED TO SWITCH NW LATE TONIGHT INTO WED...WHICH WILL FAVOR CMX DROPPING BACK DOWN TO IFR VSBYS AGAIN...AND ALLOWING SAW TO CLIMB BACK UP. CIGS IN GENERAL SHOULD REMAIN MVFR FOR THE OVERNIGHT INTO WED MORNING WITH COLD ADVECTION PREVENTING ANY LOWER DECKS FROM FORMING. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A LOW PRESSURE TROUGH AND ASSOCIATED COLD FRONT OVER LAKE SUPERIOR WILL DROP SE TODAY NIGHT AND TUE. COLD AIR FLOWING IN AND PRESSURES RISING RAPIDLY BEHIND THIS LOW WILL LIKELY PRODUCE 30 KT WINDS TODAY WITH EVEN A FEW GALE FORCE GUSTS POSSIBLE. WINDS WILL DIMINISH BELOW 25 KT FOR WED AFTERNOON THROUGH WED NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. BEHIND THIS HIGH...A TIGHTENING PRESSURE GRADIENT IS EXPECTED ON THU AS LOW PRESSURE MOVES ACROSS CENTRAL CANADA. SW WINDS STILL LOOK LIKE THEY WILL INCREASE TO GALES ON LAKE SUPERIOR FOR THU INTO THU NIGHT...ESPECIALLY NORTH CENTRAL AND EAST AREAS. EXPECT WINDS TO DIMINISH TO 30 KT OR LESS FOR FRI INTO SAT AS THE LOW MOVES TO THE EAST...BUT A SOMEWHAT TIGHT PRESSURE GRADIENT REMAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT CST / 1 AM EST WEDNESDAY FOR MIZ002-009. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ005-006. && $$ UPDATE...AJ SYNOPSIS/DISCUSSION...TAG AVIATION...AJ MARINE...JV mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1151 AM EST TUE JAN 1 2008 .UPDATE... MAIN ISSUE WITH THE FORECAST HAS BEEN LAKE EFFECT TRENDS...WHICH HAVE BEEN GOING A BIT SLOWER THAN PREVIOUSLY PLANNED. SURFACE ANALYSIS DEPICTS A TROUGH EXTENDING FROM JUST OFF THE TIP OF THE KEWEENAW TO IN-BETWEEN MUNISING AND GRAND MARAIS...AND THEN SE INTO NORTHERN LOWER MI. NORTHWEST WINDS ON THE WEST SIDE OF THIS TROUGH HAVE BEEN BRINGING LAKE EFFECT SNOW SHOWERS FROM IWD UP THROUGH THE KEWEENAW AS SEEN ON VISIBLE SATELLITE IMAGERY. HOWEVER...FLOW AS BEEN BACKING A LITTLE MORE WESTERLY OVER NORTHERN WI INTO THE WI BORDER COUNTIES...AND THIS HAS CAUSED DRIER AIR TO MOVE IN AND NOW THE SNOW IS DIMINISHING IN IWD. 12Z SOUNDING FROM GRB AND 14Z TAMDAR SOUNDING FROM RHI DEPICT THIS DRY AIR BY ONLY HAVING A THIN SATURATED LAYER AROUND 850MB. AROUND THE TROUGH...A MESO-LOW CAN BE SEEN OFF THE TIP OF THE KEWEENAW...WHICH IS GRADUALLY DROPPING SOUTH TOWARDS MARQUETTE COUNTY. NORTHEAST ORIENTED BANDS CAN BE SEEN FORMING BEHIND THE MESO-LOW. THE TIMING OF THE TROUGH DROPPING SOUTH IS CRITICAL TO THE FORECAST...AS THE LONGER THE NORTHWEST WINDS STICK AROUND...THE GREATER POTENTIAL ONTONAGON COUNTY HAS OF REACHING WARNING AND LESSER POTENTIAL FOR GOGEBIC COUNTY TO REACH WARNING. THE 12Z CANADIAN FROM YESTERDAY WAS FIRST TO PRESENT THIS IDEA OF A SLOWER TROUGH PASSAGE...AND THIS SEEMS TO BE PANNING OUT. THEREFORE HAVE INCREASED AMOUNTS A BIT IN ONTONAGON COUNTY...BUT KEPT THEM BELOW WARNING...SINCE ONCE THE TROUGH PASSES THIS AFTERNOON THE CONVERGENCE WEAKENS THERE. THE KEWEENAW STILL LOOKS FINE NOT IN ADVISORY AS WINDS WILL BE SHIFTING TO THE NNE SOON...WHICH IS A GENERAL BAD WIND DIRECTION THERE FOR LAKE EFFECT. DELAYED TIMING OF THE SNOW INTO THE NORTH CENTRAL U.P. WITH THE SLOWER TROUGH PASSAGE. HOWEVER...GIVEN THE PRESENCE OF A MESO-LOW...EXPECT SOME HEAVY SNOWFALL RATES ONCE THE TROUGH MOVES IN LATE TODAY (PER MOVEMENT EXTRAPOLATION). FARTHER EAST...WAS TEMPTED TO HOIST AN ADVISORY FOR LUCE COUNTY WITH A BAND ON THE EAST SIDE OF THE TROUGH THAT HAS REMAINED GENERALLY STATIONARY THROUGH MUCH OF THE MORNING. HOWEVER...WITH CONVERGENCE WEAKENING A LOT THIS AFTERNOON... ESPECIALLY WHEN WINDS TURN NE LATE...ADDITIONAL ACCUMULATIONS SHOULD BE ON THE LIGHT SIDE. DIMINISHED CLOUD COVER AND PCPN IN THE SOUTH CENTRAL U.P. WITH WNW WINDS HOLDING DRY AIR IN THERE. CLOUD COVER AND SNOW SHOULD PICK UP LATE IN DICKINSON/IRON WHEN THE TROUGH MOVES IN. NO CHANGES MADE TO THE TONIGHT FORECAST. && .SYNOPSIS... IR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOW AN UPPER LEVEL LOW DRIFTING SLOWLY SOUTH INTO NORTHERN MINNESOTA...WITH A BROAD TROUGH ACROSS THE CENTRAL UNITED STATES. A POTENT SHORTWAVE MOVING INTO LOWER MICHIGAN IS TOUCHING OFF PRECIPITATION ACROSS THE NORTHERN OHIO RIVER VALLEY. A BROAD RIDGE IS PUSHING ONSHORE ALONG THE WEST COAST. AT THE SURFACE...LOW PRESSURE IS DEEPENING ACROSS THE OHIO RIVER VALLEY. HIGH PRESSURE REMAINS NEARLY STATIONARY ALONG THE LENGTH OF THE ROCKY MOUNTAINS. && .DISCUSSION... TODAY AND TONIGHT...MODELS SHOW VERY GOOD AGREEMENT WITH A CONVERGENCE AREA ALREADY PRESENT AT 12Z ALONG THE WESTERN LAKE SUPERIOR SHORELINE. CONVERGENCE LOOKS TO BE FOCUSED THE BEST IN GOGEBIC AND ONTONAGON COUNTIES...WHICH IS ALSO REFLECTED BY THE WARNING IN EFFECT FOR GOGEBIC COUNTY. NAM AND LOCAL HI-RES WRF-ARW MODEL BOTH SHOW THE FAVORED CONVERGENCE ZONE MOVING OUT OF ONTONAGON COUNTY AND INTO GOGEBIC COUNTY BETWEEN 12Z AND 18Z. AM SOMEWHAT CONCERNED THAT AN ISOLATED LOCATION IN WESTERN ONTONAGON COUNTY MIGHT SEE WARNING CRITERIA...BUT HAVE DECIDED TO NOT UPGRADE THAT COUNTY. CONVERGENCE BEGINS TO DIMINISH LATE IN THE AFTERNOON AT THE SAME TIME THAT OMEGA VALUES BEGIN TO DECREASE. WINDS WILL STILL REMAIN FAVORABLE FOR CONTINUED LES AT REDUCED RATES...AND INVERSION HEIGHTS WILL BECOME TO COME DOWN AFTER MIDNIGHT. HEADLINES EXPIRING AT 06Z WEDNESDAY LOOKS FINE. MODELS SHOW A SECOND MAJOR AREA OF 950MB CONVERGENCE DEVELOPING ALONG THE MARQUETTE AND ALGER COUNTY SHORELINES IN THE LATE MORNING AND EARLY AFTERNOON HOURS. ALTHOUGH GREATEST VERTICAL MOTION WILL BE JUST BELOW THE DENDRITIC GROWTH ZONE...WINDS VEERING FROM NORTHWEST TO NORTH IN THE AFTERNOON WILL PROVIDE MAXIMUM FETCH OVER LAKE SUPERIOR AND BEST CHANCES FOR HIGH SNOWFALL RATES IN MARQUETTE COUNTY. OVERNIGHT WINDS BACK TO THE NORTHWEST AGAIN...SHIFTING AREAS OF BEST CONVERGENCE EAST INTO ALGER COUNTY. WINDS SHOULD REMAIN FAIRLY GUSTY DURING THIS TIME PERIOD...WHICH SHOULD RESULT IN BLOWING SNOW...ESPECIALLY NEAR THE SHORELINE. IN ADDITION...HIGHER WIND SPEEDS SHOULD HELP A BIT WITH COMPACTION OF SNOWPACK...AND SHOULD PREVENT SNOW-LIQUID RATIOS FROM CREEPING INTO THE 30:1 RANGE. PREVIOUS FORECAST USED RATIOS OF 25:1...AND WILL CONTINUE THAT IN THIS FORECAST. OVERALL...SNOW ACCUMULATIONS IN THIS TIME PERIOD WERE ONLY SLIGHTLY MODIFIED. WEDNESDAY...AS WINDS SHIFT MORE TO A WEST-NORTHWEST DIRECTION...SNOWFALL SHOULD BEGIN TO TAPER OFF ALONG THE WESTERN LAKE SUPERIOR SHORELINE AS A RESULT OF THE SHORTER FETCH. CONDITIONS LOOK FAVORABLE FOR ALGER COUNTY TO PICK UP ADDITIONAL SNOWFALL...WITH ACCUMULATIONS OF TWO TO FOUR INCHES DURING THE DAY...SLIGHTLY HIGHER THAN THE PREVIOUS FORECAST. LATER SHIFTS MAY NEED TO DETERMINE WHETHER THE ADVISORY IN ALGER COUNTY WOULD NEED TO BE EXTENDED LONGER THAN 12Z...ALTHOUGH THIS ENDING TIME APPEARS TO BE SUFFICIENT FOR MARQUETTE COUNTY. WEDNESDAY NIGHT THROUGH FRIDAY...MODELS APPEAR TO BE SLIGHTLY SLOWER WITH MOVING THE RIDGE INTO THE AREA...AND THEREFORE LES MIGHT PERSIST INTO WEDNESDAY EVENING. WITH CLOUDS TAKING LONGER TO MOVE OUT OF THE AREA...LOW TEMPERATURES MIGHT NOT BOTTOM OUT QUITE AS MUCH AS PREVIOUSLY EXPECTED. A WEAK TROUGH MOVES THROUGH THE AREA ON THURSDAY AFTERNOON...BUT WITH A LACK OF MOISTURE PRECIPITATION DOES NOT APPEAR TO BE LIKELY. FRIDAY NIGHT...GOING FORECAST FOR SLIGHT POPS OF FREEZING DRIZZLE AND/OR SNOW STILL LOOKS ON TARGET. SOUNDINGS SHOW DRY MID LEVELS WITH SHALLOW NEAR-SURFACE SATURATED LAYER. WITH CLOUD TOPS NO HIGHER THAN ABOUT -5C...FROZEN PRECIPITATION LOOKS LIKE IT WOULD HAVE A BETTER CHANCE OF OCCURRING. HOWEVER...GFS ONLY HAS ONE OR TWO HUNDREDTHS OF PRECIP AT THAT TIME...WITH THE ECMWF ONLY PUTTING PRECIP OUT OVER THE WESTERN HALF OF UPPER MICHIGAN. AT THIS POINT...SEE NO NEED TO MAKE ANY CHANGES. NO CHANGES MADE TO THE FORECAST BEYOND FRIDAY NIGHT. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... MVFR CONDITIONS SHOULD GRADUALLY LOWER TO IFR AT KCMX BY LATE MORNING AS BOUNDARY LAYER FLOW SHIFTS FROM NORTHWEST TO MORE FAVORABLE NORTHERLY DIRECTION BEHIND TROUGH PASSAGE. COLDER AIR BEHIND THE TROUGH WILL CONTRIBUTE TO BETTER SNOWFLAKE GROWTH AND INCREASED MIXING WILL IN TANDEM WILL LEAD TO LOWER VSBYS IN SNOW AND BLOWING SNOW. VFR CONDITIONS AT KSAW WILL ALSO LOWER TO IFR BY MID/LATE AFTERNOON WITH PASSAGE OF TROUGH AND SHIFT TO NORTHERLY WIND DIRECTION. EXPECT CONDITIONS TO IMPROVE TO MVFR BY LATE EVENING AT BOTH TAF SITES AS DRIER AIR FILTERS IN FROM NORTH OF LAKE SUPERIOR AND LES BANDS WEAKEN SOME. MVFR VSBYS AT KCMX MAY DIP DOWN TO IFR AFT 08Z WED AS A WEAK CLIPPER SHORTWAVE COULD ENHANCE LES BANDS. EXPECT VSBYS TO IMPROVE TO VFR AT KSAW BY 08Z AS WINDS BACK NORTHWEST AND LES DIMINISHES TO FLURRIES. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A LOW PRESSURE TROUGH AND ASSOCIATED COLD FRONT OVER LAKE SUPERIOR WILL DROP SE TODAY NIGHT AND TUE. COLD AIR FLOWING IN AND PRESSURES RISING RAPIDLY BEHIND THIS LOW WILL LIKELY PRODUCE 30 KT WINDS TODAY WITH EVEN A FEW GALE FORCE GUSTS POSSIBLE. WINDS WILL DIMINISH BELOW 25 KT FOR WED AFTERNOON THROUGH WED NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. BEHIND THIS HIGH...A TIGHTENING PRESSURE GRADIENT IS EXPECTED ON THU AS LOW PRESSURE MOVES ACROSS CENTRAL CANADA. SW WINDS STILL LOOK LIKE THEY WILL INCREASE TO GALES ON LAKE SUPERIOR FOR THU INTO THU NIGHT...ESPECIALLY NORTH CENTRAL AND EAST AREAS. EXPECT WINDS TO DIMINISH TO 30 KT OR LESS FOR FRI INTO SAT AS THE LOW MOVES TO THE EAST...BUT A SOMEWHAT TIGHT PRESSURE GRADIENT REMAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT CST TONIGHT FOR MIZ009. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ002. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST WEDNESDAY FOR MIZ005-006. && $$ UPDATE...AJ SYNOPSIS/DISCUSSION...TAG AVIATION...JV MARINE...JV mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 730 AM EST TUE JAN 1 2008 .SYNOPSIS... IR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOW AN UPPER LEVEL LOW DRIFTING SLOWLY SOUTH INTO NORTHERN MINNESOTA...WITH A BROAD TROUGH ACROSS THE CENTRAL UNITED STATES. A POTENT SHORTWAVE MOVING INTO LOWER MICHIGAN IS TOUCHING OFF PRECIPITATION ACROSS THE NORTHERN OHIO RIVER VALLEY. A BROAD RIDGE IS PUSHING ONSHORE ALONG THE WEST COAST. AT THE SURFACE...LOW PRESSURE IS DEEPENING ACROSS THE OHIO RIVER VALLEY. HIGH PRESSURE REMAINS NEARLY STATIONARY ALONG THE LENGTH OF THE ROCKY MOUNTAINS. && .DISCUSSION... TODAY AND TONIGHT...MODELS SHOW VERY GOOD AGREEMENT WITH A CONVERGENCE AREA ALREADY PRESENT AT 12Z ALONG THE WESTERN LAKE SUPERIOR SHORELINE. CONVERGENCE LOOKS TO BE FOCUSED THE BEST IN GOGEBIC AND ONTONAGON COUNTIES...WHICH IS ALSO REFLECTED BY THE WARNING IN EFFECT FOR GOGEBIC COUNTY. NAM AND LOCAL HI-RES WRF-ARW MODEL BOTH SHOW THE FAVORED CONVERGENCE ZONE MOVING OUT OF ONTONAGON COUNTY AND INTO GOGEBIC COUNTY BETWEEN 12Z AND 18Z. AM SOMEWHAT CONCERNED THAT AN ISOLATED LOCATION IN WESTERN ONTONAGON COUNTY MIGHT SEE WARNING CRITERIA...BUT HAVE DECIDED TO NOT UPGRADE THAT COUNTY. CONVERGENCE BEGINS TO DIMINISH LATE IN THE AFTERNOON AT THE SAME TIME THAT OMEGA VALUES BEGIN TO DECREASE. WINDS WILL STILL REMAIN FAVORABLE FOR CONTINUED LES AT REDUCED RATES...AND INVERSION HEIGHTS WILL BECOME TO COME DOWN AFTER MIDNIGHT. HEADLINES EXPIRING AT 06Z WEDNESDAY LOOKS FINE. MODELS SHOW A SECOND MAJOR AREA OF 950MB CONVERGENCE DEVELOPING ALONG THE MARQUETTE AND ALGER COUNTY SHORELINES IN THE LATE MORNING AND EARLY AFTERNOON HOURS. ALTHOUGH GREATEST VERTICAL MOTION WILL BE JUST BELOW THE DENDRITIC GROWTH ZONE...WINDS VEERING FROM NORTHWEST TO NORTH IN THE AFTERNOON WILL PROVIDE MAXIMUM FETCH OVER LAKE SUPERIOR AND BEST CHANCES FOR HIGH SNOWFALL RATES IN MARQUETTE COUNTY. OVERNIGHT WINDS BACK TO THE NORTHWEST AGAIN...SHIFTING AREAS OF BEST CONVERGENCE EAST INTO ALGER COUNTY. WINDS SHOULD REMAIN FAIRLY GUSTY DURING THIS TIME PERIOD...WHICH SHOULD RESULT IN BLOWING SNOW...ESPECIALLY NEAR THE SHORELINE. IN ADDITION...HIGHER WIND SPEEDS SHOULD HELP A BIT WITH COMPACTION OF SNOWPACK...AND SHOULD PREVENT SNOW-LIQUID RATIOS FROM CREEPING INTO THE 30:1 RANGE. PREVIOUS FORECAST USED RATIOS OF 25:1...AND WILL CONTINUE THAT IN THIS FORECAST. OVERALL...SNOW ACCUMULATIONS IN THIS TIME PERIOD WERE ONLY SLIGHTLY MODIFIED. WEDNESDAY...AS WINDS SHIFT MORE TO A WEST-NORTHWEST DIRECTION...SNOWFALL SHOULD BEGIN TO TAPER OFF ALONG THE WESTERN LAKE SUPERIOR SHORELINE AS A RESULT OF THE SHORTER FETCH. CONDITIONS LOOK FAVORABLE FOR ALGER COUNTY TO PICK UP ADDITIONAL SNOWFALL...WITH ACCUMULATIONS OF TWO TO FOUR INCHES DURING THE DAY...SLIGHTLY HIGHER THAN THE PREVIOUS FORECAST. LATER SHIFTS MAY NEED TO DETERMINE WHETHER THE ADVISORY IN ALGER COUNTY WOULD NEED TO BE EXTENDED LONGER THAN 12Z...ALTHOUGH THIS ENDING TIME APPEARS TO BE SUFFICIENT FOR MARQUETTE COUNTY. WEDNESDAY NIGHT THROUGH FRIDAY...MODELS APPEAR TO BE SLIGHTLY SLOWER WITH MOVING THE RIDGE INTO THE AREA...AND THEREFORE LES MIGHT PERSIST INTO WEDNESDAY EVENING. WITH CLOUDS TAKING LONGER TO MOVE OUT OF THE AREA...LOW TEMPERATURES MIGHT NOT BOTTOM OUT QUITE AS MUCH AS PREVIOUSLY EXPECTED. A WEAK TROUGH MOVES THROUGH THE AREA ON THURSDAY AFTERNOON...BUT WITH A LACK OF MOISTURE PRECIPITATION DOES NOT APPEAR TO BE LIKELY. FRIDAY NIGHT...GOING FORECAST FOR SLIGHT POPS OF FREEZING DRIZZLE AND/OR SNOW STILL LOOKS ON TARGET. SOUNDINGS SHOW DRY MID LEVELS WITH SHALLOW NEAR-SURFACE SATURATED LAYER. WITH CLOUD TOPS NO HIGHER THAN ABOUT -5C...FROZEN PRECIPITATION LOOKS LIKE IT WOULD HAVE A BETTER CHANCE OF OCCURRING. HOWEVER...GFS ONLY HAS ONE OR TWO HUNDREDTHS OF PRECIP AT THAT TIME...WITH THE ECMWF ONLY PUTTING PRECIP OUT OVER THE WESTERN HALF OF UPPER MICHIGAN. AT THIS POINT...SEE NO NEED TO MAKE ANY CHANGES. NO CHANGES MADE TO THE FORECAST BEYOND FRIDAY NIGHT. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... MVFR CONDITIONS SHOULD GRADUALLY LOWER TO IFR AT KCMX BY LATE MORNING AS BOUNDARY LAYER FLOW SHIFTS FROM NORTHWEST TO MORE FAVORABLE NORTHERLY DIRECTION BEHIND TROUGH PASSAGE. COLDER AIR BEHIND THE TROUGH WILL CONTRIBUTE TO BETTER SNOWFLAKE GROWTH AND INCREASED MIXING WILL IN TANDEM WILL LEAD TO LOWER VSBYS IN SNOW AND BLOWING SNOW. VFR CONDITIONS AT KSAW WILL ALSO LOWER TO IFR BY MID/LATE AFTERNOON WITH PASSAGE OF TROUGH AND SHIFT TO NORTHERLY WIND DIRECTION. EXPECT CONDITIONS TO IMPROVE TO MVFR BY LATE EVENING AT BOTH TAF SITES AS DRIER AIR FILTERS IN FROM NORTH OF LAKE SUPERIOR AND LES BANDS WEAKEN SOME. MVFR VSBYS AT KCMX MAY DIP DOWN TO IFR AFT 08Z WED AS A WEAK CLIPPER SHORTWAVE COULD ENHANCE LES BANDS. EXPECT VSBYS TO IMPROVE TO VFR AT KSAW BY 08Z AS WINDS BACK NORTHWEST AND LES DIMINISHES TO FLURRIES. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A LOW PRESSURE TROUGH AND ASSOCIATED COLD FRONT OVER LAKE SUPERIOR WILL DROP SE TODAY NIGHT AND TUE. COLD AIR FLOWING IN AND PRESSURES RISING RAPIDLY BEHIND THIS LOW WILL LIKELY PRODUCE 30 KT WINDS TODAY WITH EVEN A FEW GALE FORCE GUSTS POSSIBLE. WINDS WILL DIMINISH BELOW 25 KT FOR WED AFTERNOON THROUGH WED NIGHT AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST. BEHIND THIS HIGH...A TIGHTENING PRESSURE GRADIENT IS EXPECTED ON THU AS LOW PRESSURE MOVES ACROSS CENTRAL CANADA. SW WINDS STILL LOOK LIKE THEY WILL INCREASE TO GALES ON LAKE SUPERIOR FOR THU INTO THU NIGHT...ESPECIALLY NORTH CENTRAL AND EAST AREAS. EXPECT WINDS TO DIMINISH TO 30 KT OR LESS FOR FRI INTO SAT AS THE LOW MOVES TO THE EAST...BUT A SOMEWHAT TIGHT PRESSURE GRADIENT REMAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WARNING UNTIL MIDNIGHT CST TONIGHT FOR MIZ009. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST WEDNESDAY FOR MIZ002. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST WEDNESDAY FOR MIZ005-006. && $$ SYNOPSIS/DISCUSSION...TAG AVIATION...JV MARINE...JV mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1007 PM CST TUE JAN 1 2008 .UPDATE...SNOW REALLY STARTING TO COME DOWN IN GILE/MONTREAL. OUR SNOW OBSERVER IN THAT AREA REPORTED 2 1/2 INCHES SINCE 6 PM WITH SNOW COMING DOWN HARD WITH LARGE FLAKES. THE CITY OF HURLEY DOWNTOWN WEB CAM ALSO IS SHOWING SOME SQUALL LIKE BEHAVIOR...WITH VSBYS OCCASIONALLY RESTRICTED DUE TO FALLING SNOW. HOWEVER...IT LOOKS LIKE AS OF 10 PM...THE BEST BANDS WERE PERHAPS WEST OF HURLEY...IN THE MONTREAL AREA. SNOW SQUALLS STILL VISIBLE ON RADAR IMAGERY WITH 8-10K FT TOPS. MAY INCREASE AMOUNTS A TAD...GIVEN THE RATES OF ABOUT AN INCH AN HOUR...WITH THE POTENTIAL FOR LOCALLY HIGHER AMOUNTS IF THE BANDS CAN SUSTAIN THEMSELVES AND TRANSITION FROM MULTIPLE BANDS TO MORE SINGULAR CONVERGENT/LENSED BANDS. && .PREV DISCUSSION... /ISSUED 908 PM CST TUE JAN 1 2008/ UPDATE...MAIN FOCUS OVERNIGHT IS ON LAKE EFFECT ALONG THE SOUTH SHORE. ZONES/GRIDS UPDATED EARLIER THIS EVENING AND ARE STILL ON TRACK...SO NO ZONE UPDATED NEEDED ATTM. WINDS ARE FINALLY SWITCHING TO THE NORTH ACROSS WESTERN LAKE SUPERIOR AS TROUGH PASSES. SNOW HAS BEEN SLOW TO START...WITH GENERALLY 1 TO 3 INCHES OF ACCUMULATION SO FAR. STILL A WINDOW OF OPPORTUNITY FOR LAKE EFFECT SNOW SQUALLS...WITH 88D SHOWING SEVERAL INTENSE BANDS DEVELOPING OVER THE APOSTLE ISLANDS AND TOWARD ASHLAND/IRON AND GOGEBIC COUNTIES. BEST WE CAN DETERMINE...WE ARE SEEING TOPS AROUND 8-10K FEET. HURLEY WEB CAM NOW SHOWING TOO MUCH YET...BUT WE SHOULD START SEEING AN INCREASE SHORTLY. IF WE CAN TRANSITION FROM MULTIPLE BAND TO A LARGER CONVERGENT/LENSING BAND OFF THE BAYFIELD PENINSULA...RATES MAY BECOME EVEN GREATER FOR THE GOGEBIC RANGE AREA. WILL MAINTAIN THE LAKE EFFECT SNOW WARNING FOR ASHLAND AND IRON. BAYFIELD COUNTY HAS CONTINUED TO SEE LIGHT SNOW DURING THE EVENING...PER CONVERSATIONS WITH OUR OBSERVER IN HERBSTER... WITH A COUPLE INCHES OF FLUFFY SNOW IN HERBSTER...AND LIKELY MOST ELSEWHERE IN THE WINDWARD SIDE OF THE BAYFIELD PENINSULA. OTHER THAN THAT...THERE IS ANOTHER SHORTWAVE MOVING IN FROM SRN MANITOBA OVERNIGHT...WHICH SHOULD BRING SOME MORE CLOUDS ON OCCASION. HAVE ADDED FLURRIES FOR THE REST OF THE NIGHT ELSEWHERE BASED ON THE ARRIVAL OF THIS SYSTEM. OTHERWISE...A FAIR AMOUNT OF CLEAR SKIES IN BETWEEN FOR AN OVERALL PARTLY CLOUDY MOST AREAS. WIND CHILL ADVISORY STILL LOOKS GOOD WITH TEMPS FALLING INTO THE TEENS BELOW ZER IN MUCH OF THE ADVISORY AREA AND WINDS GRADUALLY DIMINISHING. PREV DISCUSSION... /ISSUED 312 PM CST TUE JAN 1 2008/ DISCUSSION...MAIN FORECAST CHALLENGES ARE LAKE EFFECT SNOW AND WIND CHILLS FOR TONIGHT. AFTERNOON SURFACE ANALYSIS DEPICTS TROUGH STRETCHED ACROSS LAKE SUPERIOR. THIS TROUGH HAS BEEN SLOW TO DROP SOUTHWARD...RESULTING IN A DELAY OF THE ONSET OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE. LATEST RUC FOLLOWS THE TROUGH PROGRESSION WELL AND SUGGESTS A BETTER SET UP WITH WIND FOR LES BY 22-23Z AND ESPECIALLY MORE THIS EVENING. WILL LEAVE HEADLINES AS IS...BUT LOWER SNOW AMOUNTS TO DUE SHORTER DURATION OF THE HEAVIER LES. UNDER NORTHWEST FLOW ALOFT...COLD AND STRONG HIGH PRESSURE SETTLES INTO THE RED RIVER VALLEY TONIGHT...LEAVING THE FA UNDER A 6-7MB SURFACE PRESSURE GRADIENT. WITH COLDER AIRMASS /H85 TEMPS OF -13 TO -16C/ IN PLACE...WIND CHILLS DROP INTO THE -20 TO -30 DEGREES FAHRENHEIT RANGE TONIGHT ACROSS NORTHERN MINNESOTA. WILL POST A WIND CHILL ADVISORY CONSEQUENTLY FOR AREAS THAT WILL BE COLD ENOUGH AND HAVE STRONG ENOUGH WIND SUPPORT FOR DANGEROUS WIND CHILLS. ELSEWHERE ACROSS THE DLH FA WILL STILL BE COLD AND SEE WIND CHILLS OF -10 TO -25F. LES SHOULD END QUICKLY WEDNESDAY MORNING WITH RISING HEIGHTS AND WARM AIR ADVECTION BEGINNING TO MOVE INTO THE AREA. LARGE UPPER RIDGE /CURRENTLY OVER THE WESTERN CONUS/ WILL BUILD OVER THE CENTRAL PORTION OF THE COUNTRY STARTING WEDNESDAY...THUS STARTING A MAJOR WARM-UP FOR EARLY JANUARY. GFS SUGGESTS LIGHT AMOUNTS OF PRECIP WITH SHORT WAVES ATOP THE RIDGE ON THURSDAY/THURSDAY...AND AGAIN FRIDAY NIGHT/SATURDAY. WILL LEAVE POPS OUT AT THIS TIME...BUT FLURRIES/FZDZ MAY BE NEEDED AS FORECAST SOUNDINGS SUGGEST MOISTURE TRAPPED UNDER WARM AIR INVERSION. WARM-UP LASTS THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH SOUTHWEST FLOW SETTING UP ALOFT BY THE LATTER HALF. A STRONG LOW WILL AFFECT A GOOD PORTION OF THE CENTRAL CONUS EARLY NEXT WEEK. THE TRACK IS UNCERTAIN ATTM...BUT RAIN LOOKS POSSIBLE ACROSS THE NORTHLAND. AVIATION...HIGH PRESSURE APPROACHING FROM THE WEST WILL BRING VFR CONDITIONS AND AN END TO -SN IN MN TAF SITES BY 0Z. VORT MAX MOVING INTO NW WISCONSIN WILL BRING OCCASIONAL -SN TO HYR UNTIL 0-3Z...WITH MVFR CEILINGS...OTHERWISE VFR THROUGHOUT THE PERIOD. WINDS WILL BEGIN TO WEAKEN OVERNIGHT AS RIDGE APPROACHES AFTER 3Z. && POINT TEMPS/POPS... DLH -9 8 -2 26 / 20 10 0 10 INL -14 7 0 28 / 10 10 0 10 BRD -11 9 2 28 / 10 10 0 10 HYR -8 9 -7 27 / 20 10 0 10 ASX -1 11 -2 29 / 40 20 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL 10 AM CST WEDNESDAY FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS-CROW WING- KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN AITKIN-SOUTHERN CASS-SOUTHERN COOK/LAKESHORE- SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. WI...LAKE EFFECT SNOW WARNING UNTIL 6 AM CST WEDNESDAY FOR ASHLAND- IRON. LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST WEDNESDAY FOR BAYFIELD. LS...NONE. $$ DAP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 908 PM CST TUE JAN 1 2008 .UPDATE...MAIN FOCUS OVERNIGHT IS ON LAKE EFFECT ALONG THE SOUTH SHORE. ZONES/GRIDS UPDATED EARLIER THIS EVENING AND ARE STILL ON TRACK...SO NO ZONE UPDATED NEEDED ATTM. WINDS ARE FINALLY SWITCHING TO THE NORTH ACROSS WESTERN LAKE SUPERIOR AS TROUGH PASSES. SNOW HAS BEEN SLOW TO START...WITH GENERALLY 1 TO 3 INCHES OF ACCUMULATION SO FAR. STILL A WINDOW OF OPPORTUNITY FOR LAKE EFFECT SNOW SQUALLS...WITH 88D SHOWING SEVERAL INTENSE BANDS DEVELOPING OVER THE APOSTLE ISLANDS AND TOWARD ASHLAND/IRON AND GOGEBIC COUNTIES. BEST WE CAN DETERMINE...WE ARE SEEING TOPS AROUND 8-10K FEET. HURLEY WEB CAM NOW SHOWING TOO MUCH YET...BUT WE SHOULD START SEEING AN INCREASE SHORTLY. IF WE CAN TRANSITION FROM MULTIPLE BAND TO A LARGER CONVERGENT/LENSING BAND OFF THE BAYFIELD PENINSULA...RATES MAY BECOME EVEN GREATER FOR THE GOGEBIC RANGE AREA. WILL MAINTAIN THE LAKE EFFECT SNOW WARNING FOR ASHLAND AND IRON. BAYFIELD COUNTY HAS CONTINUED TO SEE LIGHT SNOW DURING THE EVENING...PER CONVERSATIONS WITH OUR OBSERVER IN HERBSTER... WITH A COUPLE INCHES OF FLUFFY SNOW IN HERBSTER...AND LIKELY MOST ELSEWHERE IN THE WINDWARD SIDE OF THE BAYFIELD PENINSULA. OTHER THAN THAT...THERE IS ANOTHER SHORTWAVE MOVING IN FROM SRN MANITOBA OVERNIGHT...WHICH SHOULD BRING SOME MORE CLOUDS ON OCCASION. HAVE ADDED FLURRIES FOR THE REST OF THE NIGHT ELSEWHERE BASED ON THE ARRIVAL OF THIS SYSTEM. OTHERWISE...A FAIR AMOUNT OF CLEAR SKIES IN BETWEEN FOR AN OVERALL PARTLY CLOUDY MOST AREAS. WIND CHILL ADVISORY STILL LOOKS GOOD WITH TEMPS FALLING INTO THE TEENS BELOW ZER IN MUCH OF THE ADVISORY AREA AND WINDS GRADUALLY DIMINISHING. && .PREV DISCUSSION... /ISSUED 312 PM CST TUE JAN 1 2008/ DISCUSSION...MAIN FORECAST CHALLENGES ARE LAKE EFFECT SNOW AND WIND CHILLS FOR TONIGHT. AFTERNOON SURFACE ANALYSIS DEPICTS TROUGH STRETCHED ACROSS LAKE SUPERIOR. THIS TROUGH HAS BEEN SLOW TO DROP SOUTHWARD...RESULTING IN A DELAY OF THE ONSET OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE. LATEST RUC FOLLOWS THE TROUGH PROGRESSION WELL AND SUGGESTS A BETTER SET UP WITH WIND FOR LES BY 22-23Z AND ESPECIALLY MORE THIS EVENING. WILL LEAVE HEADLINES AS IS...BUT LOWER SNOW AMOUNTS TO DUE SHORTER DURATION OF THE HEAVIER LES. UNDER NORTHWEST FLOW ALOFT...COLD AND STRONG HIGH PRESSURE SETTLES INTO THE RED RIVER VALLEY TONIGHT...LEAVING THE FA UNDER A 6-7MB SURFACE PRESSURE GRADIENT. WITH COLDER AIRMASS /H85 TEMPS OF -13 TO -16C/ IN PLACE...WIND CHILLS DROP INTO THE -20 TO -30 DEGREES FAHRENHEIT RANGE TONIGHT ACROSS NORTHERN MINNESOTA. WILL POST A WIND CHILL ADVISORY CONSEQUENTLY FOR AREAS THAT WILL BE COLD ENOUGH AND HAVE STRONG ENOUGH WIND SUPPORT FOR DANGEROUS WIND CHILLS. ELSEWHERE ACROSS THE DLH FA WILL STILL BE COLD AND SEE WIND CHILLS OF -10 TO -25F. LES SHOULD END QUICKLY WEDNESDAY MORNING WITH RISING HEIGHTS AND WARM AIR ADVECTION BEGINNING TO MOVE INTO THE AREA. LARGE UPPER RIDGE /CURRENTLY OVER THE WESTERN CONUS/ WILL BUILD OVER THE CENTRAL PORTION OF THE COUNTRY STARTING WEDNESDAY...THUS STARTING A MAJOR WARM-UP FOR EARLY JANUARY. GFS SUGGESTS LIGHT AMOUNTS OF PRECIP WITH SHORT WAVES ATOP THE RIDGE ON THURSDAY/THURSDAY...AND AGAIN FRIDAY NIGHT/SATURDAY. WILL LEAVE POPS OUT AT THIS TIME...BUT FLURRIES/FZDZ MAY BE NEEDED AS FORECAST SOUNDINGS SUGGEST MOISTURE TRAPPED UNDER WARM AIR INVERSION. WARM-UP LASTS THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH SOUTHWEST FLOW SETTING UP ALOFT BY THE LATTER HALF. A STRONG LOW WILL AFFECT A GOOD PORTION OF THE CENTRAL CONUS EARLY NEXT WEEK. THE TRACK IS UNCERTAIN ATTM...BUT RAIN LOOKS POSSIBLE ACROSS THE NORTHLAND. AVIATION...HIGH PRESSURE APPROACHING FROM THE WEST WILL BRING VFR CONDITIONS AND AN END TO -SN IN MN TAF SITES BY 0Z. VORT MAX MOVING INTO NW WISCONSIN WILL BRING OCCASIONAL -SN TO HYR UNTIL 0-3Z...WITH MVFR CEILINGS...OTHERWISE VFR THROUGHOUT THE PERIOD. WINDS WILL BEGIN TO WEAKEN OVERNIGHT AS RIDGE APPROACHES AFTER 3Z. && POINT TEMPS/POPS... DLH -9 8 -2 26 / 20 10 0 10 INL -14 7 0 28 / 10 10 0 10 BRD -11 9 2 28 / 10 10 0 10 HYR -8 9 -7 27 / 20 10 0 10 ASX -1 11 -2 29 / 40 20 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL 10 AM CST WEDNESDAY FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS-CROW WING- KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS-NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS- SOUTHERN AITKIN-SOUTHERN CASS-SOUTHERN COOK/LAKESHORE- SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. WI...LAKE EFFECT SNOW WARNING UNTIL 6 AM CST WEDNESDAY FOR ASHLAND- IRON. LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST WEDNESDAY FOR BAYFIELD. LS...NONE. $$ DAP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 312 PM CST TUE JAN 1 2008 .DISCUSSION...MAIN FORECAST CHALLENGES ARE LAKE EFFECT SNOW AND WIND CHILLS FOR TONIGHT. AFTERNOON SURFACE ANALYSIS DEPICTS TROUGH STRETCHED ACROSS LAKE SUPERIOR. THIS TROUGH HAS BEEN SLOW TO DROP SOUTHWARD...RESULTING IN A DELAY OF THE ONSET OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE. LATEST RUC FOLLOWS THE TROUGH PROGRESSION WELL AND SUGGESTS A BETTER SET UP WITH WIND FOR LES BY 22-23Z AND ESPECIALLY MORE THIS EVENING. WILL LEAVE HEADLINES AS IS...BUT LOWER SNOW AMOUNTS TO DUE SHORTER DURATION OF THE HEAVIER LES. UNDER NORTHWEST FLOW ALOFT...COLD AND STRONG HIGH PRESSURE SETTLES INTO THE RED RIVER VALLEY TONIGHT...LEAVING THE FA UNDER A 6-7MB SURFACE PRESSURE GRADIENT. WITH COLDER AIRMASS /H85 TEMPS OF -13 TO -16C/ IN PLACE...WIND CHILLS DROP INTO THE -20 TO -30 DEGREES FAHRENHEIT RANGE TONIGHT ACROSS NORTHERN MINNESOTA. WILL POST A WIND CHILL ADVISORY CONSEQUENTLY FOR AREAS THAT WILL BE COLD ENOUGH AND HAVE STRONG ENOUGH WIND SUPPORT FOR DANGEROUS WIND CHILLS. ELSEWHERE ACROSS THE DLH FA WILL STILL BE COLD AND SEE WIND CHILLS OF -10 TO -25F. LES SHOULD END QUICKLY WEDNESDAY MORNING WITH RISING HEIGHTS AND WARM AIR ADVECTION BEGINNING TO MOVE INTO THE AREA. LARGE UPPER RIDGE /CURRENTLY OVER THE WESTERN CONUS/ WILL BUILD OVER THE CENTRAL PORTION OF THE COUNTRY STARTING WEDNESDAY...THUS STARTING A MAJOR WARM-UP FOR EARLY JANUARY. GFS SUGGESTS LIGHT AMOUNTS OF PRECIP WITH SHORT WAVES ATOP THE RIDGE ON THURSDAY/THURSDAY...AND AGAIN FRIDAY NIGHT/SATURDAY. WILL LEAVE POPS OUT AT THIS TIME...BUT FLURRIES/FZDZ MAY BE NEEDED AS FORECAST SOUNDINGS SUGGEST MOISTURE TRAPPED UNDER WARM AIR INVERSION. WARM-UP LASTS THROUGH THE WEEKEND INTO EARLY NEXT WEEK...WITH SOUTHWEST FLOW SETTING UP ALOFT BY THE LATTER HALF. A STRONG LOW WILL AFFECT A GOOD PORTION OF THE CENTRAL CONUS EARLY NEXT WEEK. THE TRACK IS UNCERTAIN ATTM...BUT RAIN LOOKS POSSIBLE ACROSS THE NORTHLAND. && .AVIATION...HIGH PRESSURE APPROACHING FROM THE WEST WILL BRING VFR CONDITIONS AND AN END TO -SN IN MN TAF SITES BY 0Z. VORT MAX MOVING INTO NW WISCONSIN WILL BRING OCCASIONAL -SN TO HYR UNTIL 0-3Z...WITH MVFR CEILINGS...OTHERWISE VFR THROUGHOUT THE PERIOD. WINDS WILL BEGIN TO WEAKEN OVERNIGHT AS RIDGE APPROACHES AFTER 3Z. && POINT TEMPS/POPS... DLH -9 8 -2 26 / 20 10 0 10 INL -14 7 0 28 / 10 10 0 10 BRD -11 9 2 28 / 10 10 0 10 HYR -8 9 -7 27 / 20 10 0 10 ASX -1 11 -2 29 / 40 20 10 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 10 AM CST WEDNESDAY FOR CARLTON/SOUTHERN ST. LOUIS-CENTRAL ST. LOUIS- CROW WING-KOOCHICHING-NORTHERN AITKIN-NORTHERN CASS- NORTHERN COOK/NORTHERN LAKE-NORTHERN ITASCA-NORTHERN ST. LOUIS-SOUTHERN AITKIN-SOUTHERN CASS-SOUTHERN COOK/LAKESHORE- SOUTHERN ITASCA-SOUTHERN LAKE/LAKESHORE. WI...LAKE EFFECT SNOW WARNING UNTIL 6 AM CST WEDNESDAY FOR ASHLAND- IRON. LAKE EFFECT SNOW ADVISORY UNTIL 6 AM CST WEDNESDAY FOR BAYFIELD. LS...NONE. $$ LILES/GSF/KMD mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 320 AM EST WED JAN 2 2008 .SYNOPSIS... LOW PRESSURE INTENSIFYING OFF THE NEW ENGLAND COAST WILL USHER IN THE COLDEST AIR OF THE SEASON OVERNIGHT TONIGHT AND DURING THE DAY ON WEDNESDAY. THIS WILL CAUSE LAKE EFFECT SNOW SHOWERS TO CONTINUE THROUGH TONIGHT...WEDNESDAY...AND EVEN INTO WEDNESDAY NIGHT AND THURSDAY MORNING FOR THE FINGER LAKES REGION OF CENTRAL NEW YORK. STRONG NORTHWEST WINDS WILL CAUSE BLOWING AND DRIFTING OF THE SNOW THAT FALLS...AND ALSO BRING BITTER WIND CHILLS TO THE REGION WEDNESDAY NIGHT. BY FRIDAY HIGH PRESSURE OVER THE MIDWEST WILL BEGIN TO APPROACH THE REGION...BRINGING DRY WEATHER AND MODERATING TEMPERATURES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... OLD PRIMARY LOW UP NEAR KRME RAPIDLY GIVING WAY TO DEVELOPING LOW PRESSURE ALONG THE NEW ENGLAND COAST. TROUGH TO THE SOUTHWEST OF THIS LOW IS CURRENTLY CROSSING THE CWA...BRINGING A SHIFT IN THE WINDS TO NORTHWESTERLY. AS THIS OCCURS...DEEP SYNOPTIC MOISTURE...COINCIDING WITH SOME ENHANCEMENT FROM LAKE ONTARIO AND THE FINGER LAKES IS SUSTAINING AN AREA OF SHSN OVER THE NORTHWESTERN HALF OF THE CWA...WITH SNOWS TAPERING TO FLURRIES SOUTH AND EAST OF BINGHAMTON. THE REAL ARCTIC AIR REMAINS NORTH OF LAKE ONTARIO...AND THE CURRENT LAPS ANALYSIS AND 00Z RAOB DATA SUGGEST CURRENT TEMPS ALOFT ARE ONLY MARGINAL FOR SUPPORTING LAKE EFFECT SNOW AS THEY RESIDE AROUND -10C ATTM. MORE SUBSTANTIAL COOLING WILL HOLD OFF UNTIL AFTER MIDNIGHT AS THE PRIMARY LOW VANISHES ALLOWING FOR DEEP NORTHWEST FLOW TO BECOME ESTABLISHED AND STRONG CAA TO GET GOING. SO...LAKE EFFECT MAY NOT BE TOO IMPRESSIVE UNTIL WE HEAD TOWARDS MORNING. SNOW MICROPHYSICS ALSO POINTS TO THIS...AS THE OMEGA SLOWLY LOWERS GIVEN THE DEPARTING SYNOPTIC SYSTEM...IT WILL FALL WELL BELOW THE DENDRITIC GROWTH ZONE. HAVE LEFT ACCUMS AS THEY ARE...3-5 INCHES OVERNIGHT...BUT MOST OF THIS MAY COME AFTER 9Z. HAVE ADDED BLOWING SNOW TO THE GRIDS AND ZONES WITH WINDS EXPECTED TO INCREASE TO 15G25KTS WITH THE ONSET OF COLD ADVECTION LATER TONIGHT. WINDS ALOFT DON/T SEEM TO SUPPORT MUCH MORE THAN THIS...AND THE NAM/RUC PROFILES SUGGEST A LOWERING INVERSION TOWARDS MORNING...WHICH MAY NOT ALLOW A FULL REALIZATION OF THE WINDS ALOFT. 25KTS SHOULD BE ENOUGH TO ALLOW FOR SOME BLOWING SNOW...BUT DON/T FEEL THAT WE`LL SEE WIDESPREAD 1/4 MILE VSBYS OVERNIGHT...AND THEREFORE HAVE HELD OFF ON ANY BLSN ADVISORIES THIS EVENING. FINAL TWEAKS WERE TO /1/ ADD BLOWING SNOW AGAIN TOMORROW AS INSTABILITY AGAIN INCREASES AHEAD OF AN APPROACHING SHORTWAVE HELPING TO TAP DECENT WINDS ALOFT AND /2/ ADJUST HOURLY TEMPS TO SHOW A STEADY TREND IN THE MORNING...WITH TEMPS FALLING IN THE AFTERNOON. EXPECT MOST OF THE REGION/S HIGH TEMPS TO BE SET TONIGHT AT MIDNIGHT...WITH TEMPS NOT INCREASING AGAIN UNTIL THURSDAY MORNING. FINALLY...HAVE /3/ ADDED WIND CHILL MENTION TO THE ZFP AND HWO GIVEN RELATIVELY CLOSE PROXIMITY TO WIND CHILL CRITERIA WEDNESDAY NIGHT. UPDATED PRODUCTS ARE ON THE STREET. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... LES CONTS WITH A MULTIBAND EVENT INTO THE HEART OF THE FCST AREA. EXTREME DELTA T/S HELPING THE CAUSE BUT AS IS TYPICAL IN THE NW FLOW EVENTS...A STRONG INV WILL CONT TO CAP THE SNDG. INTSTG FEATURE THOUGH IS THAT AS SHRT WV/S DROP INTO THE TROF...INV ACTUALLY WEAKENS AND RAISES LTR IN THE PD SO THAT EVEN IF THE LES FALTERS A BIT EARLY WED...BELIEVE IT WILL STRENGTHEN ONCE AGAIN LTR WED AND CONT STRONGLY INTO EARLY THU...AND PERHAPS BEYOND. HAVE POSTED AND WILL CONT ADVISORY INTO 12 THU AS I/M GENERALLY NOT XPCTG WARNING CRITERIA ACCUMS IN ANY 12 HR PD. BEST CHANCE TO EXCEED THE ADVISORY WILL BE TNGT...AND AGAIN LATE WED OR EARLY THU AS A PARTICULARLY STRONG SHRT WV DROPS IN. HAD CONSIDERED GOING WITH SOME KIND OF GENERIC FLAG CONSIDERING THE BLOWING SNOW PROBLEM AND NEAR WIND CHILL CRITERIA TO BE APRCHD THU. HWVR...IMPLIED IN A LAKE SNOW EVENT IS WIND...AND WILL BE SURE TO EMPHASIZE SAME IN THE STATEMENTS. LTR SHIFT CAN REEVALUATE THE AREAS OUTSIDE THE ADVISORY FOR EXPANSION...OR ISSUING SEPARATE EVENT SPECIFIC ADVISORIES. HIPRES BLDS IN LTR THU AND LOOKS TO MAKE FOR A VERY CHILLY NGT INTO FRI MRNG...ESP WITH THE FRESH SNOW CVR. MILDER AIR RETURNS FOR FRI. && .LONG TERM /SATURDAY THROUGH TUESDAY/... HGTS BEGIN TO RISE THRU THE EXTENDED AS SW FLOW KICKS IN AND RIDGE BUILDS OVR THE EAST. H8 TEMPS ARE PROGGED TO CLIMB WELL ABV 0C THRU THE WEEK...YIELDING HIGHS APPCHG 50F BY MID-WEEK. 00Z GFS INDICATED H5 HEIGHTS APPCH 576 ON MONDAY WITH 12Z ECMWF ONLY SLIGHTLY LOWER ON HGTS. THUS...EXPECTING MUCH ABV NORMAL TEMPS (ALMOST 20 DEGREES) TO START THE WEEK. GMOS GUIDANCE APPEARS TO BE ON THE CHILLY SIDE BASED ON PATTERN AND HAVE BUMPED TEMPS UP SEVERAL DEGREES TO START OFF THE PD. RIDGE AXIS WILL KEEP MAJORITY OF SYSTEM/WK WAVES TO THE NORTH AND HAVE LOWERED GMOS POPS THRU THE ENTIRE LONG TERM PORTION OF THE FCST AS IT TYPICALLY TRENDS TOWARD CLIMO IN THE LATTER PDS. BEST CHC OF RAIN LOOKS TO BE ON WEDNESDAY AS FRONTAL BNDRY MVS THRU. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... LAKE ENHANCED SNOW SHOWERS BHND DEPARTING LOW WILL KEEP MVFR/IFR CONDS OVRNGT AT TYPICAL LES TERMINALS. CIGS WILL BE LOWEST WITH OCNL LIFR CONDS AT KITH AS NW FLOW BRINGS IN 100FT CIGS. OCNL IFR EXPECTED AT KRME/KSYR/KBGM WITH CIGS BTWN 300-800FT EXPECTED THRU AT LEAST 10Z. PREDOMINANT CLD BASES EXPECTED TO BE ARND 1500FT. CIGS IMPRV AT KELM/KAVP WHERE LAKE ENHANCED SNOW SHOWERS WILL NOT HAVE MUCH OF AN IMPACT EXCEPT FOR OCNL MVFR CIGS. CONDS GRADUALLY IMPRV THRU THE DAY BUT DO NOT EXPECT CIGS TO RISE TO VFR UNTIL EARLY TO MID-AFTERNOON WHEN DRIER AIR TRIES TO WORK IN. VSBYS ALSO TO BE IMPACTED IN -SHSN WITH SYR/RME/BGM/ITH OCNLY DROPPING TO IFR THIS MRNG. AS THE DAY GOES ON...LAKE EFFECT SNOWS WILL GRADUALLY BCM MORE SCATTERED WITH LESS OF AN IMPACT ON TERMINALS. WINDS WILL RMN OUT OF THE NW WITH GUSTS FROM 20-25KTS EARLY AS STRONG CDFNT PLOWS THRU THE REGION. WINDS MAY RELAX A LITTLE ARND DAYBREAK BUT WILL PICK UP AGAIN AFTER 15Z. THURSDAY NIGHT THRU SUNDAY...LAKE EFFECT SNOWS EXPECTED TO INCREASE LATE WED NIGHT...GENERALLY AFTER 06Z WITH NNW FLOW ONCE AGAIN. THIS WILL BRING SNOW SHOWERS BACK TO THE SAME AREAS AS FLOW MOVES OVER LK ONTARIO AND THE FINGER LAKES. MVFR/IFR CONDS EXPECTED AGAIN OVRNGT AND POSSIBLY CONTINUING INTO THUR AFTN BEFORE SFC RIDGE FINALLY BRINGS AN END TO SNOW. THE NEXT WEAK WAVE WILL MV THRU SAT NIGHT INTO SUNDAY WITH LIGHT MIXED PCPN POSSIBLE AND MVFR CIGS/VSBYS THRU RMNDR OF OUTLOOK PD. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THURSDAY FOR NYZ015>018-023-025-044. && $$ SYNOPSIS...JMA NEAR TERM...JMA SHORT TERM...DGM LONG TERM...PVB AVIATION...PVB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1244 AM EST WED JAN 2 2008 .SYNOPSIS... LOW PRESSURE CENTERED OVER WESTERN NEW YORK STATE IS REDEVELOPING THIS AFTERNOON ALONG THE SOUTH COAST OF NEW ENGLAND. THE SECONDARY LOW WILL INTENSIFY NEAR CAPE COD AND INTO THE GULF OF MAINE TONIGHT BEFORE REACHING THE CANADIAN MARITIMES BY WEDNESDAY MORNING. PERIODS OF SNOW WILL CONTINUE ACROSS THE NORTH COUNTRY THROUGH TONIGHT...FOLLOWED BY AN ARCTIC AIR MASS MOVING INTO THE REGION AS THE LOW DEPARTS TO OUR EAST WEDNESDAY MORNING. ARCTIC AIR REMAINS IN PLACE THROUGH THURSDAY FOLLOWED BY A SIGNIFICANT WARMING TREND THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1030 PM EST...THE MAIN PCPN FM THE PARENT AND DVLPG COASTAL HAS LIFTED NE OF FA WITH BUFCAN SHOWING DECENT BANDING ACRS ST LWRNC VLY ARD MONTREAL. THIS BANDING AND DEFORMATION BAND DVLPMNT SSW ACRS NRN NY ARE THE PLAY MAKERS FOR THE REST OF THIS EVENT. ERLR IR IMAGERY SUGGESTING SOME COOLING TOPS AND RDR COMPOSITE COLLABORATES THIS ACTVTY ACRS SRN ADRNDKS HAS NOW STARTED TO ABATE SOMEWHAT. LATEST MDL DATA INCLDG RUC AND LCL WRF POINTS THAT THE STG BANDING STRUCTURE WL PRIMARILY REMAIN IN CANADA BUT SHIFT PRECARIOUSLY CLOSE TO NRN BDR COMMUNITIES AT TIMES. DEFORMATION BAND STRUCTURE TO SLOWLY OVRNGT BUT AS LLVL WNDS BCM NNW ACRS CHMPL VLY AND NW SLOPES OF NRN GRNS...XPCT LCL ENHANCEMENT WITH LAKE CHAMPLAIN CONVERGENCE. SO...AT THIS TIME THE BIG QUESTION REMAINS ON HOW MUCH ADDTNL AND WHETHER TO DROP WRNGS OR DOWNGRADE OR A COMBINATION. IN THE END...KEPT WRNGS IN NRN NY ALG BDR DUE TO SOME ADDTNL SNOW BUT MORE DUE TO BLOWING SNOW WITH INCREASE NNW GRADIENT OF 15-20KTS. IN NC-NE AND NRN GRN MTNS HV KEPT WSW DUE TO DEFORMATION BAND AND UPSLOPING COMPONENTS THAT CUD BRG 2-4 ADDTNL WITH LCLLY MORE AND EVENTUAL BLOWING SNOW. ELSEWHERE...DOWNGRADED TO ADV FOR LGT ADDTNL BUT BLOWING TOWARD MRNG. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... AS OF 247 PM EST TUESDAY...SFC LOW WILL BE EXITING ACROSS NOVA SCOTIA AT 12Z WED WITH SOME LINGERING LIGHT MORNING SNOW SHOWERS. ALTHOUGH MUCH DRIER AIR WILL HELP END THE SNOW SHOWERS AND ALLOW FOR PARTLY TO MOSTLY SUNNY CONDITIONS BY WEDNESDAY AFTERNOON...THE STRONG COLD-AIR ADVECTION WILL OFFSET ANY DIURNAL TEMPERATURE TRENDS LEAVING READINGS MAINLY IN THE TEENS...AND UPPER SINGLE DIGITS IN THE ADIRONDACKS FOR DAYTIME HIGHS. ALL IN ALL...MOST LOCATIONS WILL SEE NEARLY STEADY TEMPERATURE READINGS THROUGHOUT WEDNESDAY. WIND CHILL VALUES WILL RANGE FROM ZERO TO -10F...MAKING FOR A BRISK DAY /N TO NW WINDS 10-20 MPH WITH GUSTS TO 35 MPH IN THE MORNING/. WEDNESDAY NIGHT...SFC RIDGE BUILDS EWD INTO THE ERN GREAT LAKES REGION WITH NNWLY GRADIENT FLOW CONTINUING ACROSS THE FA. VERTICAL DIRECTIONAL SHEAR DECREASES WEDNESDAY NIGHT...AND WITH STEEP LOW-LEVEL LAPSE RATES...INVERSION HEIGHTS OF 3.5-4.0 KFT...AND A MOSTLY ICE FREE REGION OF LAKE CHAMPLAIN...WE SHOULD GET A NNW-SSE ORIENTED LAKE SNOW BAND DEVELOP OVER LAKE CHAMPLAIN. THIS BAND WILL BRING SNOW SHOWERS TO THE IMMEDIATE SHORELINE FROM BTV TO CHARLOTTE TO FERRISBURG...WITH PERHAPS 1-2 INCHES OF SNOW ACCUMULATION VCNTY OF SHELBURNE...CHARLOTTE...AND FERRISBURG BY THURSDAY MORNING. ELSEWHERE...LOOKING AT ONE OF THE COLDEST MORNINGS OF THE SEASON WITH WIDESPREAD READINGS 0F TO -10F. THURSDAY...LOOKS FAIR AND COLD WITH HIGH PRESSURE CRESTING OVER THE NORTH COUNTRY. NO PCPN EXPECTED...LIGHT WINDS...AND HIGHS IN THE +5 TO +10F RANGE EXCEPT LOW TEENS IN THE KVSF AREA OF THE CT VALLEY. THURSDAY NIGHT...SFC RIDGE AXIS SHOULD BE SHIFTING EAST OF THE NORTH COUNTRY. SOME MID-UPR CLOUDS AND LIGHT SWLY WINDS MAY LIMIT RADIATIVE COOLING IN NRN NY. MEANWHILE...PBL SHOULD BE STRONGLY DECOUPLED WITH LONGER PERIOD OF CLEAR SKIES IN NERN VT. THUS...SOME EAST-WEST VARIABILITY IN LOW TEMPERATURES EXPECTED FOR FRIDAY MORNING. WILL GO -10F TO -20F IN NERN VT...0 TO -5F IN THE CHAMPLAIN VALLEY...AND 0 TO -10F ACROSS MOST OF NRN NY. && .LONG TERM /FRIDAY THROUGH TUESDAY/... VERY QUIET EXTENDED FORECAST AGAIN TODAY. STRONG HIGH PRESSURE WILL DOMINATE THE PATTERN...WITH BLOCKING PATTERN SET UP ALONG THE EAST COAST. GENERALLY DRY AND WARM WEATHER WILL BE IN CONTROL OF THE WEATHER. ARCTIC AIR MASS BEGINS TO PUSH OUT OF THE AREA ON FRIDAY MORNING...AS HIGH PRESSURE SLIDES OFFSHORE BUT GETS STUCK THERE. BROAD SOUTH AND/OR SOUTHWEST FLOW WILL DOMINATE THE WEATHER PATTERN THROUGH THE EXTENDED PERIOD...AND TEMPERATURES WILL BE WELL ABOVE SEASONAL NORMALS. CONTINUED TO STAY CLOSE TO GRIDDED MOS NUMBERS...AND BLENDED IN THE MEX MOS. WITH PRONOUNCED RIDGING ACROSS THE EASTERN CONUS...PRIMARY JET AND STORM TRACK SHOULD BE DEFLECTED OFF TO THE NW...KEEPING MOST OF THE CWA DRY. HAVE ONLY INCLUDED CHANCE IN EXTENDED PERIOD FOR MOST NORTHERN ZONES CURING A COUPLE PERIODS...OTHERWISE POPS WILL BE MINIMAL. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... MVFR/IFR CONDS TO PERSIST IN -SN AND BLSN THROUGH THE MID MORNING HOURS AS GUSTY NORTHWESTERLY SFC FLOW IS USHERED IN BEHIND ARCTIC SFC BNDRY PUSHING ACROSS FA ATTM. EXPECT CONDS TO IMPROVE THROUGH THE AFTERNOON HOURS AT MOST SITES AS MEAN COLUMNAR MOISTURE PROFILES CONTINUE TO THIN...THOUGH STILL SOME LOCALIZED IFR CONDS IN -SN/BLSN ALONG AND JUST EAST OF LK CHAMPLAIN INVOF KBTV. ANY LINGERING FLURRIES OR VERY LIGHT SNOWS THEN BASICALLY END INTO THE EVENING HOURS AS MOST SITES SCATTER OUT LEAVING PC CONDS INTO THE OVERNIGHT HOURS. SOME LINGERING MVFR CONDS AND SCT FLURRIES STILL POSSIBLE JUST EAST OF LK CHAMPLAIN HOWEVER. 06Z THURSDAY THROUGH SUNDAY...LOW TO MID LVL MOISTURE CONTS TO THIN OUT WED NGT AS MID LVL TROF AXIS SLOWLY SHIFTS E WITH MID LVL AND SFC RIDGING MVG INTO FA FOR THU. SFC HI SHIFTS S WITH RETURN FLOW AT LLVLS AND WNW FLOW AT MID LVLS BRINGING SOME WEAK ENERGY BY FRI FOR PSBLTY OF CHC -SHSN. SFC FLOW CONTS THE SAME WITH MID LVL FLOW BCMG WSW DRG WKND FOR GRDL WRMG AND ANTHR CHC OF -SHRA LATE SAT-SUN. BASICALLY...VFR CONDS XPCTD FOR MUCH OF PERIOD WITH PSBL LCLZD MVFR IN -SHSN FRI. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR VTZ003- 004-006>008-016-017. SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR VTZ001-002-005- 009-010-018-019. NY...WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR NYZ026- 027-029>031-087. SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ028-034-035. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS/SLW SHORT TERM...BANACOS/RJS LONG TERM...JAN AVIATION...SLW/JMG ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1230 PM EST WED JAN 2 2008 .SYNOPSIS...A VIGOROUS UPPER LEVEL TROUGH WILL SWEEP THROUGH DURING THE AFTERNOON. FOLLOWING THE TROUGH...STRONG...ARCTIC HIGH PRESSURE OVER THE PLAINS WILL BUILD EASTWARD INTO THE MID ATLANTIC REGION THROUGH THURSDAY NIGHT...LINGERING OVER OUR AREA THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1000 AM WEDNESDAY...THE UPPER-LEVEL TROUGH WAS MOVING INTO CENTRAL NORTH CAROLINA WITH LOCAL RADAR IMAGES SHOWING ISOLATED AREAS OF HIGHER REFLECTIVITY TOWARD KDAN AND JUST WEST OF KRZZ. ALTHOUGH THE KGSO 12Z SOUNDING WAS DRY...WITH PRECIPITABLE WATER VALUES ONLY 0.08 INCH...AND NOT MUCH MORE MOIST AT EITHER KRNK OR KMHX...THERE WAS DECENT MOISTURE ALONG AND JUST NORTH OF THE 850MB AND 700MB TROUGH AXES MOVING INTO AND ACROSS THE STATE. CLOUD TOPS WERE WARMING EAST OF THE MOUNTAINS...WHERE BOTH THE NAM AND THE RUC FORECAST OVERALL SUBSIDENCE DURING THE AFTERNOON. DESPITE THIS...THE STRENGTH OF THE SHORTWAVE WAS SUFFICIENT EVEN WITH LIMITED MOISTURE TO PROVIDE FOR PATCHY LIGHT SNOW REACHING THE GROUND PARTICULARLY AT KDAN...WHERE THE VISIBILITY FELL BRIEFLY TO JUST UNDER 2 MILES. THE VISIBILITY HAS SINCE RISEN THERE AS OF 10 AM. UPDATED THE GRIDDED AND WORDED FORECASTS TO REINTRODUCE ISOLATED SNOW SHOWERS TO AREAS MAINLY ALONG AND NORTH OF U.S. 64...WHERE THE MOISTURE ON THE MORE AGGRESSIVE NAM...COMPARED TO THE RUC... IS GREATEST DURING THE DAY AT 850MB AND 700MB. ADDED FLURRIES JUST A LITTLE FARTHER SOUTH GIVEN THE STRENGTH OF THE UPPER WAVE AND THE LATEST RADAR TRENDS. KGSO AND AMDAR SOUNDINGS NEAR KRDU WERE VERY SIMILAR IN SHOWING WINDS ALOFT OF 25-30KT AND INCREASED SURFACE WINDS IN A WELL-MIXED BOUNDARY LAYER TO 35 MPH...WHICH COINCIDES WITH SOME OBSERVATIONS SHOWING WIND GUSTS OF 30 TO 35 MPH. FINALLY...GIVEN THE COLD AIR ADVECTION WITH 850MB TEMPERATURES INTO THE NEGATIVE MIDDLE TEENS...AND AN INCREASE IN CLOUDS EXPECTED WITH THE PASSAGE OF THE UPPER WAVE ESPECIALLY NORTHERN ZONES...HIGHS IN THE LOWER TO MID 30S NORTH...TO 35 TO 40 SOUTH...APPEAR REASONABLE WITH ONLY MINOR ADJUSTMENTS MADE. WHERE ADJUSTMENTS WERE MADE...THEY WERE SLIGHTLY LOWER FOR THE HIGHS THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AS OF 145 AM WED...THE SHARP TROUGH ALOFT EXITS EAST OF THE AREA TONIGHT AND CONDITIONS STABILIZE WITH SUBSIDENCE WARMING AND DRYING ALOFT. THE THERMAL TROUGH BOTTOMS OUT OVER THE AREA EARLY THU MORNING WITH 850 MB TEMPERATURES NEAR MINUS 12-14C. THE SURFACE LAYER REMAINS STIRRED WITH GRADIENT NW FLOW OVERNIGHT...BUT TEMPERATURES SHOULD STILL DROP TO AROUND 20 THROUGHOUT THE CWA WITH A WIND CHILL NEAR 10 DEGREES TOWARD DAYBREAK THU. LOW LEVEL THICKNESS FOR THU IS CLOSE TO VALUES OF TODAY...WHICH TRANSLATES TO HIGHS MAINLY IN THE 30S UNDER SUNNY SKIES. THE COLDEST TEMPERATURES THIS SERIES COMES THU NIGHT WITH THE SURFACE HIGH CENTERING OVER THE AREA AND MAXIMUM RADIATIONAL COOLING. LOWS OF 15 TO 20 ARE LIKELY. AIRMASS MODERATION SHOULD SET IN WITH RIDGING ALOFT ON FRI...850 TEMPERATURES RISING ABOVE 0C IN WESTERLY FLOW... AND LOW LEVEL THICKNESS EXCEEDING 1305M. CIRRUS MAY BEGIN TO ADVECT INTO THE AREA FROM THE WEST...BUT OTHERWISE SUNSHINE SHOULD WARM THE SURFACE TEMPERATURES INTO THE MID TO UPPER 40S. -RFG && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 AM WED...THE MEDIUM RANGE PERIOD CONTINUES TO BE CHARACTERIZED BY A BROAD TROUGH OVER THE WESTERN U.S. AND ANOMALOUS STRONG RIDGING ALONG THE EAST COAST. GFS AND ECMWF BEGIN TO DIVERGE WITH REGARD TO THE EASTWARD PROGRESSION OF THE WESTERN TROUGH BY TUE. THEY ALSO DISAGREE ON THE PATH OF A SOUTHERN STREAM SHORT WAVE OVER THE WEEKEND WITH GFS ALONG THE GULF COAST AND THE ECMWF ACROSS THE CAROLINAS. BUT DIFFERENCES SHOULD BE LARGELY INCONSEQUENTIAL TO SENSIBLE WEATHER. TEMPERATURES SHOULD BE ABOVE TO WELL-ABOVE NORMAL DURING THIS PERIOD WITH LITTLE PROSPECT FOR RAINFALL. THE PATTERN TYPE OF LIGHT SE FLOW INTO A RIDGE OVER THE CAROLINA AND A MOISTENING BOUNDARY LAYER SUGGESTS SOME INCREASE IN MORNING FOG POTENTIAL SUN-TUE. FRI NIGHT-MON...THE SURFACE HIGH DRIFTS OFF THE MID ATLANTIC COAST BUT LEAVES A SHARP AXIS EXTENDING WEST ACROSS NC. UPPER LEVELS BECOME MOIST OVER THE WEEKEND AND THIS IS APT TO RESULT IN VARIABLE AMOUNTS OF CIRRUS WITH DEFORMATION IN THE FLOW AT JET LEVEL. HIGH CLOUDINESS WILL LIMIT MAX TEMPERATURE POTENTIAL...BUT STILL ABOUT A 3-5 DEGREE INCREASE IN DIURNAL EXTREMES CAN BE EXPECTED EACH DAY THROUGH THE PERIOD. LOWER TO MID LEVELS REMAIN RELATIVELY DRY EXCEPT FOR SOME BOUNDARY LAYER SATURATION IN SE FLOW POSSIBLE BY SUN INCREASING POTENTIAL FOR EARLY MORNING FOG. MON NIGHT-TUE...TEMPERATURE EXTREMES SHOULD BE RANGING ABOUT 15 DEGREES ABOVE NORMAL. SOUTHERLY FLOW BECOMES CONFLUENT AND THE AIRMASS BEGINS TO DESTABILIZE BY LATE TUE. HOWEVER...THE UPPER TROUGH AND ASSOCIATED COLD FRONT REMAIN WELL WEST OF THE AREA WITH LITTLE PROSPECT FOR RAINFALL UNTIL PERHAPS LATER IN THE WEEK. -RFG && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 1230 PM...BREEZY NORTHWEST WINDS WITH GUSTS BETWEEN 25 AND 30KT WILL CONTINUE UNTIL JUST BEFORE SUNSET...BUT BOTH THE NAM AND GFS BUFR SOUNDINGS SHOW A WELL-MIXED ATMOSPHERE IN THE BOUNDARY LAYER THROUGH THE NIGHT WHICH SHOULD PROVIDE FOR A STEADY WIND THAT SLOWLY VEERS MORE NORTHERLY DURING THE TAF PERIOD. WINDS ARE SLIGHTLY LESS THURSDAY...BUT WITH WINDS IN THE FIRST 150MB OR SO REMAINING TO 15-25KTS OFF OF THE SURFACE...STRONGER TOWARD THE EAST...BREEZY CONDITIONS WILL EXIST ONCE AGAIN AT THE SURFACE. AFTER THE STRONG SHORTWAVE MOVES THROUGH LATE THIS AFTERNOON...WITH THE POTENTIAL FOR FLEETING MVFR AND A LIGHT FLURRY OR SNOW SHOWER...VFR CONDITIONS WILL DOMINATE UNDER A MOSTLY CLEAR OR CLEAR SKY. MODEL SOUNDINGS ARE VERY DRY FOR TONIGHT THROUGH THURSDAY. IF THE GFS VERIFIES...THERE IS THE POTENTIAL FOR BRIEF MVFR OR EVEN IFR CEILINGS SATURDAY NIGHT INTO SUNDAY MORNING WITH SOME RETURN FLOW AND INCREASED LOW-LEVEL MOISTURE FROM THE SOUTHEAST. THIS COULD ALSO TAKE PLACE LATE MONDAY. OTHERWISE...UNDER HIGH PRESSURE...VFR CONDITIONS WILL PREVAIL. && .FIRE WEATHER... AS OF 1025 AM...NORTHWEST WINDS OF 15 TO 25 MPH WITH GUSTS UP TO 35 MPH COUPLED WITH MINIMUM RH VALUES BETWEEN 25 AND 30 PERCENT... WILL CREATE ADVERSE FIRE CODITIONS THIS AFTERNOON... DESPITE RECENT RAINFALL. THE WINDY AND VERY DRY AIR... CHARACTERIZED BY SURFACE DEWPOINTS IN THE SINGLE DIGITS... WILL QUICKLY REDUCE FINE FUEL MOISTURE TO THE SINGLE DIGITS. IN FACT... THE LATEST AVAILABLE DATA FROM YESTERDAY INDICATES THAT 10 HOUR DEAD FUEL MOISTURE WAS BETWEEN 7 AND 8 PERCENT... AND THESE SHOULD CERTAINLY BE AS LOW OR LIKELY LOWER TODAY. PER COORDINATION WITH STATE FORESTRY OFFICIALS ON TUESDAY...A RED FLAG WARNING WILL CONTINUE FOR ALL OF CENTRAL NC THROUGH 5 PM THIS AFTERNOON. && .RAH WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING 9 AM TO 5 PM TODAY FOR ALL OF CENTRAL NC. && $$ SYNOPSIS...DJF/RFG NEAR TERM...DJF SHORT TERM...RFG LONG TERM...RFG AVIATION...DJF FIRE WEATHER...MWS nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 700 AM EST WED JAN 2 2008 .SYNOPSIS...LOW PRESSURE OVER NEW ENGLAND AND STRONG HIGH PRESSURE OVER THE PLAINS WILL DRIVE MUCH COLDER AIR INTO THE MID ATLANTIC REGION TODAY. THIS HIGH PRESSURE SYSTEM WILL THEN DRIFT SLOWLY EAST OVER THE AREA THURSDAY...THEN PRODUCE A GRADUAL WARMING TREND FROM FRIDAY INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 100 AM WEDNESDAY...THE JET AXIS ALOFT OVERHEAD EARLY THIS MORNING DRIFTS EAST...INDICATING MAINLY SUBSIDENCE IN THE UPPER LEVELS TODAY. DIFFERENTIAL VORTICITY AT THE BASE OF THE TROUGH AT 700-500 MB IS VERY FLEETING AS IT MOVES FROM NEAR THE BLUE RIDGE MTNS TO THE COAST 12-18Z. RUC FORECAST SOUNDINGS SHOW NO SATURATION OVER THE AREA AT 12Z. NAM AND GFS FORECAST SOUNDINGS SHOW MOISTENING LATER THIS MORNING TO NEAR SATURATION AT 850-650 MB...BUT THE LAPSE RATE IS NOT AS STEEP AS PREVIOUS MODEL RUNS AND REMAINS LESS THAN 6.0C/KM IN THE MOIST LAYER EXCEPT SLIGHTLY ABOVE 6.0C/KM NEAR THE VA BORDER. CURRENTLY SURFACE DEW POINTS ARE RUNNING DRIER THAN GUIDANCE IN THE TRIAD...AND INDEED THE BOUNDARY LAYER REMAINS VERY DRY THROUGHOUT TODAY IN THE FORECAST SOUNDINGS. THE FEW SNOW SHOWERS THAT MAY DEVELOP LATER THIS MORNING ACROSS NORTHERN SECTIONS ARE LIKELY TO SUBLIMATE ON THE WAY DOWN WITH ONLY A FEW FLURRIES AT MOST EXPECTED AT THE SURFACE. SURFACE TEMPERATURES ARE GETTING COLDER...BUT JUST GETTING BELOW FREEZING NOW IN THE NW AND ONLY EXPECTED TO BE A COUPLE DEGREES BELOW FREEZING FARTHER EAST AROUND DAYBREAK. THIS LIMITS THE POTENTIAL FOR TRACE AMOUNTS OF SNOW CAUSING PROBLEMS THIS MORNING AS SURFACE WARMING TAKES HOLD WITH DAYLIGHT. SO IN A NUTSHELL...SCATTERED FLURRIES ARE POSSIBLE THIS MORNING BUT CHANCES FOR MEASURABLE SNOW AND NEGATIVE CONSEQUENCES APPEAR SLIM NORTH TO NEGLIGIBLE SOUTH. TRUE TO PREVIOUS MODEL FORM...1000-850 MB THICKNESS STARTS THE DAY AT 1250-1255M AND RISES TO AROUND 1265-1275M. THIS SUGGESTS THAT TEMPERATURES WILL STRUGGLE TO REACH 40 DEGREES TODAY AND LIKELY STAY WELL SHORT IN THE MID 30S NW. GUSTY WNW WINDS...WITH GUSTS UP TO 30 MPH WILL PRODUCE WIND CHILL IN THE TEENS NW EARLY AND LOWER TO MID 20S DURING THE DAY THROUGHOUT THE CWA. -RFG && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AS OF 145 AM WED...THE SHARP TROUGH ALOFT EXITS EAST OF THE AREA TONIGHT AND CONDITIONS STABILIZE WITH SUBSIDENCE WARMING AND DRYING ALOFT. THE THERMAL TROUGH BOTTOMS OUT OVER THE AREA EARLY THU MORNING WITH 850 MB TEMPERATURES NEAR MINUS 12-14C. THE SURFACE LAYER REMAINS STIRRED WITH GRADIENT NW FLOW OVERNIGHT...BUT TEMPERATURES SHOULD STILL DROP TO AROUND 20 THROUGHOUT THE CWA WITH A WIND CHILL NEAR 10 DEGREES TOWARD DAYBREAK THU. LOW LEVEL THICKNESS FOR THU IS CLOSE TO VALUES OF TODAY...WHICH TRANSLATES TO HIGHS MAINLY IN THE 30S UNDER SUNNY SKIES. THE COLDEST TEMPERATURES THIS SERIES COMES THU NIGHT WITH THE SURFACE HIGH CENTERING OVER THE AREA AND MAXIMUM RADIATIONAL COOLING. LOWS OF 15 TO 20 ARE LIKELY. AIRMASS MODERATION SHOULD SET IN WITH RIDGING ALOFT ON FRI...850 TEMPERATURES RISING ABOVE 0C IN WESTERLY FLOW... AND LOW LEVEL THICKNESS EXCEEDING 1305M. CIRRUS MAY BEGIN TO ADVECT INTO THE AREA FROM THE WEST...BUT OTHERWISE SUNSHINE SHOULD WARM THE SURFACE TEMPERATURES INTO THE MID TO UPPER 40S. -RFG && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 130 AM WED...THE MEDIUM RANGE PERIOD CONTINUES TO BE CHARACTERIZED BY A BROAD TROUGH OVER THE WESTERN U.S. AND ANOMALOUS STRONG RIDGING ALONG THE EAST COAST. GFS AND ECMWF BEGIN TO DIVERGE WITH REGARD TO THE EASTWARD PROGRESSION OF THE WESTERN TROUGH BY TUE. THEY ALSO DISAGREE ON THE PATH OF A SOUTHERN STREAM SHORT WAVE OVER THE WEEKEND WITH GFS ALONG THE GULF COAST AND THE ECMWF ACROSS THE CAROLINAS. BUT DIFFERENCES SHOULD BE LARGELY INCONSEQUENTIAL TO SENSIBLE WEATHER. TEMPERATURES SHOULD BE ABOVE TO WELL-ABOVE NORMAL DURING THIS PERIOD WITH LITTLE PROSPECT FOR RAINFALL. THE PATTERN TYPE OF LIGHT SE FLOW INTO A RIDGE OVER THE CAROLINA AND A MOISTENING BOUNDARY LAYER SUGGESTS SOME INCREASE IN MORNING FOG POTENTIAL SUN-TUE. FRI NIGHT-MON...THE SURFACE HIGH DRIFTS OFF THE MID ATLANTIC COAST BUT LEAVES A SHARP AXIS EXTENDING WEST ACROSS NC. UPPER LEVELS BECOME MOIST OVER THE WEEKEND AND THIS IS APT TO RESULT IN VARIABLE AMOUNTS OF CIRRUS WITH DEFORMATION IN THE FLOW AT JET LEVEL. HIGH CLOUDINESS WILL LIMIT MAX TEMPERATURE POTENTIAL...BUT STILL ABOUT A 3-5 DEGREE INCREASE IN DIURNAL EXTREMES CAN BE EXPECTED EACH DAY THROUGH THE PERIOD. LOWER TO MID LEVELS REMAIN RELATIVELY DRY EXCEPT FOR SOME BOUNDARY LAYER SATURATION IN SE FLOW POSSIBLE BY SUN INCREASING POTENTIAL FOR EARLY MORNING FOG. MON NIGHT-TUE...TEMPERATURE EXTREMES SHOULD BE RANGING ABOUT 15 DEGREES ABOVE NORMAL. SOUTHERLY FLOW BECOMES CONFLUENT AND THE AIRMASS BEGINS TO DESTABILIZE BY LATE TUE. HOWEVER...THE UPPER TROUGH AND ASSOCIATED COLD FRONT REMAIN WELL WEST OF THE AREA WITH LITTLE PROSPECT FOR RAINFALL UNTIL PERHAPS LATER IN THE WEEK. -RFG && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 700 AM WEDNESDAY...VFR CONDITIONS EXPECTED ACROSS THE TAF PERIOD. A STRONG UPPER LEVEL TROUGH WILL CROSS THE AREA TODAY RESULTING IN SCATTERED TO OCCASIONALLY BROKEN CLOUDS AROUND 6 THOUSAND FEET THROUGH ABOUT 15Z... OTHERWISE CLEAR SKIES SHOULD PREVAIL. THERE IS ALSO A POSSIBILITY OF A FEW FLURRIES OVER THE INT/GSO AREA DURING THE MORNING. AS THE UPPER LEVEL TROUGH MOVES ACROSS THE AREA STRONG UPPER LEVEL NORTHWEST WINDS WILL MIX DOWN TO THE SURFACE. WINDS WILL BECOME QUITE GUSTY DURING THE LATE MORNING TO EARLY AFTERNOON. SUSTAINED WINDS AT 15 KNOTS WITH GUSTS TO 25 KNOTS THIS MORNING WILL INCREASE TO 20 KNOTS WITH GUSTS TO 30 KNOTS DURING THE EARLY AFTERNOON. AFTER SUNSET WINDS WILL DIMINISH TO 12 KNOTS WITH GUSTS TO 25 KNOTS... THEN DROP TO NORTHWEST AT 12 TO 15 KNOTS. STRONG HIGH PRESSURE WILL BUILD TOWARD THE CAROLINAS ON THURSDAY... BECOMING CENTERED OVER THE TAF AREA FRIDAY... AND THEN MOVE EAST OF THE AREA SATURDAY. RIDGING WILL EXTEND WEST INTO THE AREA LATE SATURDAY AND SUNDAY FROM THE OFFSHORE CENTER OF THE HIGH PRESSURE AREA. VFR CONDITIONS EXPECTED THURSDAY THROUGH SUNDAY. && .FIRE WEATHER... NW WINDS OF 15-25 MPH WITH FREQUENT GUSTS TO AROUND 30 MPH COUPLED WITH MINIMUM RH VALUES NEAR 25 PERCENT HAS CREATED ADVERSE CONDITIONS FOR FIRE CONTROL...DESPITE RECENT RAINFALL. THE WINDY DRY AIR HAS THE POTENTIAL TO QUICKLY REDUCE FINE FUEL MOISTURE TO THE SINGLE DIGITS. FOLLOWING COORDINATION WITH STATE FORESTRY OFFICIALS YESTERDAY...A RED FLAG WARNING HAS BEEN ISSUED FOR 9 AM TO 5 PM TODAY FOR ALL OF CENTRAL NC. && .RAH WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING 9 AM TO 5 PM TODAY FOR ALL OF CENTRAL NC. && $$ SYNOPSIS...RFG NEAR TERM...RFG SHORT TERM...RFG LONG TERM...RFG AVIATION...RHJ FIRE WEATHER...RFG nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 113 AM EST WED JAN 2 2008 .SYNOPSIS...STRONG HIGH PRESSURE OVER THE PLAINS AND DEPARTING LOW PRESSURE OFF THE NEW ENGLAND COAST WILL DRIVE COLD AIR INTO THE AREA TODAY AND TONIGHT. HIGH PRESSURE WILL DRIFT SLOWLY ACROSS THE AREA THU AND FRI. && .NEAR TERM /THROUGH TODAY/... AS OF 100 AM WEDNESDAY...THE JET AXIS ALOFT OVERHEAD EARLY THIS MORNING DRIFTS EAST...INDICATING MAINLY SUBSIDENCE IN THE UPPER LEVELS TODAY. DIFFERENTIAL VORTICITY AT THE BASE OF THE TROUGH AT 700-500 MB IS VERY FLEETING AS IT MOVES FROM NEAR THE BLUE RIDGE MTNS TO THE COAST 12-18Z. RUC FORECAST SOUNDINGS SHOW NO SATURATION OVER THE AREA AT 12Z. NAM AND GFS FORECAST SOUNDINGS SHOW MOISTENING LATER THIS MORNING TO NEAR SATURATION AT 850-650 MB...BUT THE LAPSE RATE IS NOT AS STEEP AS PREVIOUS MODEL RUNS AND REMAINS LESS THAN 6.0C/KM IN THE MOIST LAYER EXCEPT SLIGHTLY ABOVE 6.0C/KM NEAR THE VA BORDER. CURRENTLY SURFACE DEW POINTS ARE RUNNING DRIER THAN GUIDANCE IN THE TRIAD...AND INDEED THE BOUNDARY LAYER REMAINS VERY DRY THROUGHOUT TODAY IN THE FORECAST SOUNDINGS. THE FEW SNOW SHOWERS THAT MAY DEVELOP LATER THIS MORNING ACROSS NORTHERN SECTIONS ARE LIKELY TO SUBLIMATE ON THE WAY DOWN WITH ONLY A FEW FLURRIES AT MOST EXPECTED AT THE SURFACE. SURFACE TEMPERATURES ARE GETTING COLDER...BUT JUST GETTING BELOW FREEZING NOW IN THE NW AND ONLY EXPECTED TO BE A COUPLE DEGREES BELOW FREEZING FARTHER EAST AROUND DAYBREAK. THIS LIMITS THE POTENTIAL FOR TRACE AMOUNTS OF SNOW CAUSING PROBLEMS THIS MORNING AS SURFACE WARMING TAKES HOLD WITH DAYLIGHT. SO IN A NUTSHELL...SCATTERED FLURRIES ARE POSSIBLE THIS MORNING BUT CHANCES FOR MEASURABLE SNOW AND NEGATIVE CONSEQUENCES APPEAR SLIM NORTH TO NEGLIGIBLE SOUTH. TRUE TO PREVIOUS MODEL FORM...1000-850 MB THICKNESS STARTS THE DAY AT 1250-1255M AND RISES TO AROUND 1265-1275M. THIS SUGGESTS THAT TEMPERATURES WILL STRUGGLE TO REACH 40 DEGREES TODAY AND LIKELY STAY WELL SHORT IN THE MID 30S NW. GUSTY WNW WINDS...WITH GUSTS UP TO 30 MPH WILL PRODUCE WIND CHILL IN THE TEENS NW EARLY AND LOWER TO MID 20S DURING THE DAY THROUGHOUT THE CWA. -RFG && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 300 PM TUESDAY...VERY COLD AIR WILL SETTLE OVER FORECAST AREA AS HIGH PRESSURE BUILDS INTO REGION BEHIND EXITING UPPER LEVEL SYSTEM. SKIES WILL CLEAR BY SUNSET WED NIGHT WHILE WINDS WILL GRADUALLY SUBSIDE. DO NOT EXPECT AIR MASS TO DECOUPLE OVERNIGHT WHICH WILL ALLOW AIR NEAR SURFACE TO REMAIN MIXED. THIS SHOULD RESULT IN MIN TEMPS NEAR 20 DEGREES WITH WIND CHILL VALUES LATE WED NIGHT THROUGH EARLY THU MORNING BETWEEN 10 AND 15 DEGREES. 850 THERMAL TROUGH OVER REGION THU WITH 850 TEMPS MINUS 12 TO MINUS 14. WHILE NOT AS BLUSTERY AS WED...STOUT NORTH WIND THU AND AFTERNOON TEMPS ONLY IN THE 35-40 DEGREE RANGE WILL MAKE IT A VERY CHILLY DAY. SURFACE RIDGE SETTLES OVER THE AREA, SETTING UP FOR IDEAL COOLING CONDITIONS. MINIMUM TEMPERATURES FRI MORNING 15-20 DEGREES WITH THE NORMALLY COLDER LOCALES (LOUISBURG, HENDERSON, RURAL HALL) HOVERING BETWEEN 10-13 DEGREES. AIR MASS WILL BEGIN GRADUAL MODERATION FRI AS L/W TROUGH LIFTS NE. 850MB TEMPS WARM ABOVE FREEZING AND LOW LEVEL FLOW BECOMES SW. TEMPS SHOULD REBOUND 25-30 DEGREES FROM MORNING LOWS. -WSS && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 130 AM WED...THE MEDIUM RANGE PERIOD CONTINUES TO BE CHARACTERIZED BY A BROAD TROUGH OVER THE WESTERN U.S. AND ANOMALOUS STRONG RIDGING ALONG THE EAST COAST. GFS AND ECMWF BEGIN TO DIVERGE WITH REGARD TO THE EASTWARD PROGRESSION OF THE WESTERN TROUGH BY TUE. THEY ALSO DISAGREE ON THE PATH OF A SOUTHERN STREAM SHORT WAVE OVER THE WEEKEND WITH GFS ALONG THE GULF COAST AND THE ECMWF ACROSS THE CAROLINAS. BUT DIFFERENCES SHOULD BE LARGELY INCONSEQUENTIAL TO SENSIBLE WEATHER. TEMPERATURES SHOULD BE ABOVE TO WELL-ABOVE NORMAL DURING THIS PERIOD WITH LITTLE PROSPECT FOR RAINFALL. THE PATTERN TYPE OF LIGHT SE FLOW INTO A RIDGE OVER THE CAROLINA AND A MOISTENING BOUNDARY LAYER SUGGESTS SOME INCREASE IN MORNING FOG POTENTIAL SUN-TUE. FRI NIGHT-MON...THE SURFACE HIGH DRIFTS OFF THE MID ATLANTIC COAST BUT LEAVES A SHARP AXIS EXTENDING WEST ACROSS NC. UPPER LEVELS BECOME MOIST OVER THE WEEKEND AND THIS IS APT TO RESULT IN VARIABLE AMOUNTS OF CIRRUS WITH DEFORMATION IN THE FLOW AT JET LEVEL. HIGH CLOUDINESS WILL LIMIT MAX TEMPERATURE POTENTIAL...BUT STILL ABOUT A 3-5 DEGREE INCREASE IN DIURNAL EXTREMES CAN BE EXPECTED EACH DAY THROUGH THE PERIOD. LOWER TO MID LEVELS REMAIN RELATIVELY DRY EXCEPT FOR SOME BOUNDARY LAYER SATURATION IN SE FLOW POSSIBLE BY SUN INCREASING POTENTIAL FOR EARLY MORNING FOG. MON NIGHT-TUE...TEMPERATURE EXTREMES SHOULD BE RANGING ABOUT 15 DEGREES ABOVE NORMAL. SOUTHERLY FLOW BECOMES CONFLUENT AND THE AIRMASS BEGINS TO DESTABILIZE BY LATE TUE. HOWEVER...THE UPPER TROUGH AND ASSOCIATED COLD FRONT REMAIN WELL WEST OF THE AREA WITH LITTLE PROSPECT FOR RAINFALL UNTIL PERHAPS LATER IN THE WEEK. -RFG && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 700 PM TUESDAY...VFR CONDITIONS ARE GENERALLY EXPECTED THROUGHOUT THE TAF PERIOD. A STRONG UPPER LEVEL WAVE WILL CROSS THE FORECAST AREA WEDNESDAY MORNING THROUGH EARLY AFTERNOON. EXPECT BKN/OVC STRATUS AT 5 TO 8 THOUSAND FEET DEVELOPING BY SUNRISE IN THE NW PIEDMONT...WITH THE RDU/FAY AND RWI TAF SITES SHORTLY THEREAFTER. A FEW CONVECTIVE SNOW SHOWERS WILL BE POSSIBLE IN ASSOCIATED WITH THE PASSAGE OF THE UPPER LEVEL WAVE...BETWEEN ROUGHLY 12 AND 19Z FROM WEST TO EAST. HAVE INCLUDED TEMPO GROUPS FOR LIGHT SNOW SHOWERS AND ASSOCIATED IFR/MVFR VISIBILITIES DURING THE 12 TO 19Z TIME FRAME. CEILINGS IN ANY SHOWER ACTIVITY ARE EXPECTED TO REMAIN VFR...IN THE 3 TO 4 THOUSAND FOOT RANGE. SKIES WILL CLEAR OUT FROM WEST TO EAST IN THE SUBSIDENCE BEHIND THE UPPER LEVEL WAVE DURING THE AFTERNOON HOURS. BLUSTERY CONDITIONS ARE ALSO EXPECTED WITH STRONG COLD AIR ADVECTION THROUGHOUT THE TAF PERIOD. WEST WINDS DURING THE OVERNIGHT HOURS ARE EXPECTED TO REMAIN AT 10 TO 14 KNOTS...BECOMING NORTHWEST AND INCREASING TO 15 TO 20 KNOTS AROUND SUNRISE...WITH GUSTS AS HIGH AS 30 KNOTS FROM MID TO LATE MORNING UNTIL SUNSET. NORTHWEST WINDS OF 10 TO 15 KNOTS WITH GUSTS UP TO 25 KNOTS WILL REMAIN POSSIBLE FOR SEVERAL HOURS AFTER SUNSET WEDNESDAY NIGHT. THESE WINDS ARE BASED ON FORECAST SOUNDINGS WHICH SHOW 25 TO 35 KNOT LOW LEVEL NORTHWEST FLOW IN A MIXED LAYER THAT EXTENDS UP TO 850 MILLIBARS. STRONG (1040-1045 MB) HIGH PRESSURE BUILDS TOWARD THE CAROLINAS ON THURSDAY...BECOMING CENTERED OVER THE FORECAST AREA FRIDAY AND SATURDAY...MOVING OFFSHORE WITH RIDGING EXTENDING WEST INTO THE AREA ON SUNDAY. VFR CONDITIONS ARE EXPECTED FROM WEDNESDAY NIGHT THROUGH SUNDAY. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... && $$ SYNOPSIS...RFG NEAR TERM...RFG SHORT TERM...WSS LONG TERM...RFG AVIATION...VINCENT nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1030 AM CST WED JAN 2 2008 .DISCUSSION... HIGH AMPLITUDE RIDGE AXIS OVER THE HIGH PLAINS WILL MOVE INTO THE WESTERN DAKOTAS THIS AFTERNOON. SURFACE WINDS WILL BECOME SOUTH AND INCREASE TO 10 TO 20 MPH IN THE WESTERN ZONES LATE THIS AFTERNOON...LESS ELSEWHERE. FOG LOOP SHOWS A PATCH OF CLOUDS ROUGHLY BETWEEN GFK AND FAR WITH LITTLE MOVEMENT. BAND OF MID AND HIGH CLOUDS WERE SPILLING OVER THE UPPER RIDGE AND INTO MUCH OF THE WESTERN ZONES. TAMDAR SOUNDINGS SUGGEST GFS...RUC AND NAM ARE A BIT TOO WARM AT 925 HPA AND 850 HPA. RUC WAS THE CLOSEST TO OBSERVED. RUC CROSS SECTION INDICATED SOME DRYING IN THE 850 TO 700 HPA LAYER. TEMPERATURES MAY HAVE A DIFFICULT TIE RISING TODAY WITH MID AND HIGH LEVEL CLOUDS. MAY HAVE TO REDUCE TEMPS. && .PREVIOUS DISCUSSION.../ISSUED 230 AM CST WED JAN 2 2008/ FORECAST CHALLENGE CONCERNS MAINLY TEMPERATURES. MODELS IN REASONABLE AGREEMENT THROUGH PERIOD ALTHOUGH BOTH GFS AND NAM INITIALIZED TO WARM THROUGH COLUMN. WILL USE BLEND FOR FORECAST. WEAK SHORTWAVE AND ASSOCIATED SURFACE TROUGH AFFECTING FA EARLY THIS MORNING. RELATIVELY NARROW BAND OF MAINLY VFR CIGS AND FLURRIES PROVIDING BRIEF RELIEF IN TEMPERATURE DROP HOWEVER EXPECT CLOUDS TO EXIT FA TO THE SOUTH AND EAST TOWARDS DAYBREAK WHICH SHOULD STILL ALLOW FOR DECENT TEMPERATURE DROP AS SURFACE RIDGE AXIS BUILDS IN. WILL MONITOR TRENDS FOR SOME EARLY AM FLURRIES/CLOUDS. OTHERWISE RIDGE AXIS SHIFTS QUICKLY EAST DURING DAY WITH INCREASING WARM ADVECTION AND MIXING...MAINLY DURING MID AFTERNOON INTO EARLY EVENING. WARMEST TEMPERATURES TODAY LIKELY WILL BE WESTERN FA FIRST TO SEE BEST MIXING AND WARM ADVECTION. REMAINDER WILL LIKELY SEE TEMPERATURES SLOWLY WARM LIKELY INTO THE EVENING SO MAXIMUM TEMPERATURES MAY GET TRICKY. WILL CONTINUE TO TREND COOLEST MAXIMUM VALUES THROUGH VALLEY. MID LEVEL RIDGE FLATTENS AS IT SHIFTS EAST OVER FA TONIGHT SETTING FAIRLY QUICK ZONAL FLOW. GRADIENT TIGHTENS UP THIS EVENING AND CONTINUES OVERNIGHT WITH WINDS LIKELY HOLDING IN WINDY RANGE. LITTLE ADDITIONAL SNOWFALL SHOULD LIMIT ANY MOVING SNOW TO SOME MINOR GROUND DRIFTING. WITH MIXING AND CONTINUED WARM ADVECTION TEMPERATURES LIKELY TO HOLD FAIRLY STEADY WITH ONLY A MINOR DROP AT WORST DEPENDING ON DEGREE OF CLOUD COVER. JUST HOW WARM AREA GETS THE REMAINDER OF WORK WEEK WILL BE BIG CHALLENGE. 850MB TEMPERATURES SOAR BY FRIDAY AND WILL ACT TO STRENGTHEN LOW LEVEL INVERSION. ALSO LOOKS TO BE PLENTY OF MID/UPPER LEVEL CLOUDS WHICH WILL LIMIT TEMPERATURE DROP DURING NIGHT HOWEVER MAY LIMIT ANY HELP SOLAR PROVIDES DURING DAY. NUMERICAL GUIDANCE PRETTY CLOSE THURSDAY HOWEVER DIFFERS BY NEARLY 10 DEGREES BY FRIDAY. AT THIS POINT WILL KEEP TEMPERATURES CONSERVATIVE...CLOSER TO COOLER MAV NUMERICAL GUIDANCE. REASONING BEING WARMEST ELEVATED TEMPERATURES ON FRIDAY MAKING FOR SHARP INVERSION AND SURFACE FLOW REMAINS OUT OF THE SOUTH VS MORE FAVORABLE WARMING SW FLOW. MILD PATTERN CONTINUES INTO WEEKEND WITH THERMAL RIDGE AXIS OVER FA SATURDAY. WILL CAUTIOUSLY NUDGE TEMPERATURES UPWARD HOLDING COOLEST READING WITHIN VALLEY. WEAK SURFACE TROUGH/COLD FRONT CROSSES FA SUNDAY SO WILL MAINTAIN LOW POPS. SYSTEM EARLY NEXT WEEK LOOKS LIKE BEST POTENTIAL FOR PCPN AND WILL NEED WATCHING. AT THIS POINT WILL KEEP CURRENT POPS GOING. && .AVIATION... WITH HIGH PRESSURE RIDGE AXIS OVER THE NORTHERN PLAINS THIS MORNING MOST OF THE AREA IS IN VFR CONDITIONS WITH A PATCH OF LOW STRATUS LYING ACROSS THE EASTERN SIDE OF THE RED RIVER VALLEY JUST SOUTHEAST OF GFK TO FAR. THIS BAND IS PRODUCING IFR CONDITIONS WITH CIGS UNDER 500FT IN FAR. WITH WEAK MIXING AND A MID LEVEL DECK MOVING ACROSS ND EXPECT CONDITIONS TO SLOWLY IMPROVE THIS AFTERNOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ HOPPES/JK nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 330 AM CST WED JAN 2 2008 .SHORT TERM...TODAY THROUGH FRIDAY NIGHT... ARCTIC HIGH PRESSURE IS CURRENTLY CENTERED OVER SOUTHWESTERN MANITOBA. TEMPERATURES ACROSS THE REGION VARYING FROM ZERO TO 10 BELOW ZERO IN CLEAR AREAS TO 5 TO 10 ABOVE UNDER CLOUD COVER. THIS DOME OF COLD ARCTIC AIR IS FORECAST TO MOVE SOUTHEAST OUT OF THE REGION TODAY. WINDS LIGHT ACROSS THE STATE NOW...BUT WINDS ARE EXPECTED TO INCREASE DURING THE DAY OUT OF THE SOUTH...IN RESPONSE TO DEEPENING LOW PRESSURE IN THE LEE OF THE CANADIAN ROCKIES. AT UPPER LEVELS A STRONG ELONGATED LONGWAVE RIDGE OVER THE ROCKIES WILL MOVE EAST INTO THE PLAINS. THE SURFACE LOW IN THE LEE OF THE CANADIAN ROCKIES MOVES EAST ACROSS CENTRAL CANADA WEDNESDAY NIGHT AND THURSDAY...BUT BROAD SURFACE LOW PRESSURE REDEVELOPS IN THE LEE OF THE CANADIAN ROCKIES BETWEEN A LARGE UPPER LEVEL LOW OFF THE WEST COAST AND THE UPPER LEVEL RIDGE OVER THE EASTERN CONUS. THIS WILL KEEP WARM ADVECTION AND SOUTH WINDS OVER THE DAKOTAS. EACH DAY OF THE SHORT TERM WILL SEE HIGHER MAXIMUM TEMPERATURES. TODAY`S HIGHS FROM 10 ABOVE IN MY EASTERN COUNTIES TO THE LOWER 30S IN THE SOUTHWEST...AND BY FRIDAY HIGHS SHOULD BE IN THE LOWER 30S EAST TO MID 40S WEST. NO PRECIPITATION EXPECTED. .LONG TERM...SATURDAY THROUGH TUESDAY NIGHT... EARLY CHALLENGE WILL BE TEMPERATURES ON SATURDAY. SOUTH TO SOUTHWESTERLY FLOW IN ASSOCIATION WITH CYCLOGENESIS IN CENTRAL ALBERTA WILL MAINTAIN +4 TO +6 850MB TEMPERATURES ACROSS THE CWA. EMBEDDED SHORTWAVE ENERGY IN BROAD CYCLONIC FLOW ACROSS THE WESTERN CONUS AND NOSE OF UPPER LEVEL JET WILL OVERSPREAD WESTERN AND CENTRAL NORTH DAKOTA ON SATURDAY. THIS WILL PROVIDE FOR MID TO HIGH LEVEL CLOUD SHIELDS...REDUCING TOTAL INSOLATION. MODEL SOUNDINGS ALSO INDICATE WEAK MIXING DURING THE DAY ON SATURDAY...FURTHER REDUCING HEATING POTENTIAL. THEREFORE LEFT TEMPS IN THE UPPER 40S ACROSS THE SOUTHWEST COMPARED TO THE 50S SEEN THIS DECEMBER AND TRENDED COOLER OVER WHAT WILL REMAIN OF THE SNOW PACKS DURING THIS MILD SPELL. WEAK IMPULSES WILL TRANSIT THE CWA ON SATURDAY NIGHT AND INTO SUNDAY PRODUCING AN AREA OF RAIN TRANSITIONING TO SNOW PER THERMAL PROFILES. BELIEVE GFS IS OVERDONE WITH QPF AND REDUCED POPS SLIGHTLY AS MOISTURE WILL BE LACKING WITH THESE IMPULSES AS HAS BEEN THE TREND THIS SEASON. LOW CONDENSATION PRESSURE DEFICITS TIED WITH ISENTROPIC AND FRONTOGENETIC FORCING ASSOCIATED WITH THE BEGINNING STAGES OF LEE CYCLOGENESIS WILL PRODUCE A SNOW BAND ACROSS WESTERN NORTH DAKOTA SUNDAY NIGHT AND INTO MONDAY MORNING. POPS ADDED TO REFLECT THIS PRECIP AREA. GFS IS MUCH FASTER WITH DEVELOPMENT AND PROPAGATION OF THE MID WEEK WINTER STORM AND RESULTING DEFORMATION SNOW BAND ACROSS THE CWA. WILL LEAVE TO DAY SHIFT TO ADJUST TUE AND WED POPS. HOWEVER...BELIEVE THE GFS WILL SLOW DOWN ITS PROGRESSION OF THE LOW CLOSER TO THE ECMWF SOLUTION AS HAS BEEN THE TREND THIS WINTER. && .AVIATION... A BAND OF 600 TO 1500 FOOT CEILINGS LAY ACROSS THE NORTHERN PART OF THE STATE EARLY THIS MORNING. THE RUC13 MODEL INDICATES THAT THIS BAND WILL TRANSLATE EAST AND MIX OUT BY 18Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE $$ JV/PA/RL nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1246 AM EST WED JAN 2 2008 .SYNOPSIS... SNOW SHOWERS WILL PERSIST THROUGH WEDNESDAY NIGHT...HEAVIER IN THE MOUNTAINS. WARMER WEATHER THIS WEEKEND MELTING THE PENDING SNOWFALL WITH HIGH PRESSURE IN CONTROL. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SNOW SHOWERS CONTINUE ACROSS THE FCST AREA...HWVR INTENSITY HAS SLACKENED OUTSIDE THE MTNS. WATER VAPOR LOOP ILLUSTRATES A WELL DEFINED S/W MOVING THRU SRN IND AND NRN KY ATT AND WILL CROSS SWRN VA AND NERN TN OVRNGT. IR PICKS UP ON THIS FEATURE AS WELL WITH AN AREA OF ENHANCED / COOLER CLOUD TOPS. EXPECT SHSN TO FILL BACK IN AFT 6Z WITH BRIEF PDS OF HVY SN AS TROP LOWER TO H5 JUST TO OUR S. NCEP MDLS PEG H5-H3 QVEC CONV COUPLED WITH STEEP H7-H5 LAPSE RATES ACROSS WV THAT COULD YIELD TO A QUICK INCH OF ACCUM. NAM/GFS/RUC ALL SUPPORT AN AREA OF DEFORMATION BTWN H7-H6 AND PVU 15 PRES ADV CROSSING AFT MDNGT. SHSN WILL BE AIDED BY LAKE PLUMES OF MI GIVEN LLVL TRAJECTORY. TIGHT PRES GRADIENT KEEPS BLUSTERY CONDS GOING WITH WIND CHILLS IN THE SINGLE DIGITS AND TEENS. AREAS OF BLOWING SNOW EXPECTED OVER THE HIGHER TERRAIN. LOWERED ACCUM A LITTLE IN THE TRI STATE INTO SRN WV AS LESS THAN A HALF INCH AS FALLEN AND DO NOT EXPECT MORE THAN AN INCH OVERNIGHT. ELSEWHERE...ACCUM ARE ON TRACK WITH REPORTS OF 2 TO 3 INCHES ALREADY IN PARTS OF THE NRN MTNS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... LIFT FROM VORT MAX MOVES OVER SOUTHERN COUNTIES TO BEGIN WEDNESDAY. WILL INCREASE POPS FOR THIS FEATURE. WARM AIR ADVECTION BEHIND VORTICITY LOBE INDUCES A LOW LEVEL INVERSION THAT SHOULD CAP OUT SNOW SHOWERS BEHIND THE VORTICITY LOBE AND LIMIT ACCUMULATIONS FOR A TIME. ATMOSPHERE GRADUALLY DESTABILIZES AGAIN WEDNESDAY AFTERNOON AS COLDER AIR MOVES BACK IN. WILL INCREASE POPS WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT ACCORDINGLY. LATE WEDNESDAY NIGHT DRY AIR BEGINS TO BATTLE THE UPSLOPE. THIS SHOULD KEEP THE UPSLOPE CLOSER TO THE MOUNTAINS. WARM AIR ADVECTION SETS IN ON THURSDAY...BRINGING AN END TO THE PRECIPITATION. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... COLD ADVECTION JUST SHUTTING OFF AT START OF PERIOD WITH LOW LEVEL FLOW STILL NW IN THE MOUNTAINS. THINK THERE WILL STILL BE SOME CLOUD THERE AT THIS TIME AND...AS COLD AS THE AIR MASS IS...THE LAST FLAKES OF SNOW WILL NOT BE GONE UNTIL THE CLOUDS ARE JUST ABOUT GONE. THEREFORE EXTENDED FLURRIES INTO THU EVENING. OTHERWISE SURFACE HIGH SAILS ACROSS AND S OF THE AREA THU NT ULTIMATELY ALLOWING CLEAR SKY EVERYWHERE. TOOK TEMPERATURES DOWN TOWARD THE NEW LOWER GUIDANCE WITH RADIATIVE COOLING SETUP. FOR THE BALANCE OF THE PERIOD...SURFACE HIGH PRESSURE SETS UP OFF THE SE COAST WHILE AN UPPER LEVEL LONG WAVE TROUGH SETS UP IN THE W. WEAK SHORT WAVES COMING OUT OF THIS LONG WAVE IN THE FAST FLOW OFF THE PACIFIC BRING PERIODIC INCREASE IN THE CHANCE OR PRECIPITATION. THE OVERRIDING THEME THOUGH SHOULD BE MILD AND FOR THE MOST PART DRY...UNTIL A STRONGER SHORT WAVE FINALLY BREAKS THROUGH THE E COAST RIDGE. THIS IS PROGGED TO OCCUR NEAR THE END OF THE PERIOD. USED MOSGUIDE FOR THE MOST PART...ALTHOUGH LEANED MORE TOWARD HPC FOR POPS DAYS 6-7. USED MOSTLY A BLEND OF THE ONGOING PACKAGE AND THE NEW MOSGUIDE FOR MOST HIGHS AND LOWS DURING DAYS3-7. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... LAKE EFFECT SNOW BANDS WILL MOVE SOUTH OVERNIGHT BRINGING MOST TAF LOCATIONS TO IFR VIS IN AND MVFR CEILINGS OVER THE NEXT FEW HOURS. AFTER 12Z...EXPECT LOWLAND TAF SITES TO GO TO MVFR VIS IN MORE SCATTERED SNOW SHOWERS...WHILE NORTHWESTERLY FLOW TAKES CONTROL AND KEEPS UPSLOPE SNOW GOING AT EKN AND BKW. WILL LEAVE THEM IN IFR VIS THROUGH THE FORECAST PERIOD. IMPROVEMENTS EXPECTED AFTER 06Z THURSDAY. AVIATION OUTLOOK /BEYOND 06Z THURSDAY/ UPSLOPE SNOW ENDS THURSDAY AFTERNOON...WITH HIGH PRESSURE BUILDING IN. VFR RETURNING DURING THE DAY...AND CANNOT DISCOUNT FG POSSIBILITIES WITH SNOW MELT/MOIST GROUND AND WARMER TEMPERATURES WITH CALM WINDS OVERNIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...SNOW AND BLOWING SNOW ADVISORY UNTIL 4 AM EST THURSDAY FOR WVZ032>040. SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ009>011- 015>020-027>031. WINTER STORM WARNING UNTIL 4 AM EST THURSDAY FOR WVZ046-047. OH...SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ066-067-075- 076. KY...NONE. VA...SNOW AND BLOWING SNOW ADVISORY UNTIL 4 AM EST THURSDAY FOR VAZ003-004. && $$ SYNOPSIS...TRM/MDP/RPY NEAR TERM...29/MDP SHORT TERM...RPY LONG TERM...TRM AVIATION...26 oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1247 AM EST TUE JAN 1 2008 .SYNOPSIS... A COLD FRONT WHIPS THROUGH LATE TONIGHT. MUCH COLDER AIR MOVES IN NEW YEARS DAY WITH WIND BLOWN SNOW SHOWERS OF VARYING INTENSITY THRU THURSDAY MORNING. MODERATING TEMPERATURES FRIDAY AND THIS WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... COLD FRONT CONTS TO MOVE THRU CNTRL PORTIONS OF IND AND KY ATT. SFC LOW MOVES NE THROUGH THE LWR GRTLKS TNGT WITH PCPN MOSTLY CONFINED TO NRN SECTIONS OF THE CWA. KLVX ILLUSTRATES ECHOES INTENSIFYING IN THE WARM SECTOR AHEAD OF THE BAROCLINIC ACR WRN KY. 18Z NAM AND LCL MESO MDLS SHOW TRACE AT BEST FM I-64 S WHEN BOUNDARY PASSES...HWVR LATEST RUC13 CATCHES ON TO DEVELOPING QPF OVER KY AND MARCHES IT THRU I-64 S OVRNGT. OBS SUPPORT A TRACE TO A HUNDREDTH...SO WILL KEEP POPS IN THE CHC RANGE...BUT INC THEM TO CAT ALL ACR THE N. SRLY WINDS KEEP TEMPS AOA FREEZING TNGT MAKING PTYPE ALL RAIN AS INDICATED BY 9Z SREF PLUMES AT VARIOUS LOCATIONS THROUGHOUT FCST AREA. ANY SN ACCUM BY THE FIRST DAWN OF 2008 SHALL BE ABV 3000 FT WHERE AN INCH IS PSBL. INCREASED WIND AND WIND GUST GRIDS AFT LOOKING AT MAX MIXING POTENTIAL OFF BUFR SNDGS. STRONG ISALLOBARIC FLOW COULD PUSH GUST TO 35KTS WITH ANY RW ALONG THE FRONT. WINDS DROP ONLY A LTL NEW YEARS DAY AS PRESSURE GRADIENT REMAINS TIGHT AS CYCLONE COILS UP. ANY THUNDER OR LIGHTNING SHALL STAY IN CLOSE PROXIMITY OF LOW WHERE IMPRESSIVE DYNAMICS ARE LOCATED. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... SOME MINOR DIFFERENCES IN TIMING OF COLD AIR...BUT EFFECT ON THE FORECAST IS THE SAME. COLD AIR MOVES IN TUESDAY WITH SNOW SHOWERS DEVELOPING. MUCH COLDER ARCTIC AIR MASS THEN MOVES IN TUESDAY NIGHT. STRONG VORT LOBE PASSING JUST SOUTH OF THE REGION SHOULD HELP ENHANCE THE UPSLOPE SNOWFALL. WILL EXPAND THE WINTER STORM WATCH DOWN THROUGH RALEIGH COUNTY DUE TO THIS ENHANCEMENT. CONCERNED THAT UPSLOPE EVENT WILL BE HAMPERED A BIT ON WEDNESDAY BY SOME WARM AIR ADVECTION AND LOW LEVEL INVERSION. && .LONG TERM /THURSDAY THROUGH MONDAY/... STRONG DEEP LAYER NW UPSLOPE FLOW CONTINUES GRADUALLY DIMINISHING WED NT INTO THU. SNOW WILL GRADUALLY WIND DOWN WED NT AS THE FLOW AND ASSOCIATED COLD ADVECTION WEAKEN. LOWERED HIGHS THU EVEN FURTHER WITH HIGH PRESSURE AND SUBSIDENCE INVERSION TRAPPING LOW LEVEL COLD AIR. LOW LEVEL MODEL TEMPERATURES ARE LOWEST AT H925. SW FLOW DOES ENSUE THU AND STRENGTHENS FRI THRU SUN AS STRONG HIGH MOVES OFFSHORE AND LOW PRESSURE MOVES E ACROSS SOUTHERN CANADA. CHANCE POPS W OF OH RIVER AND ACROSS NORTHERN WV SAT AFTERNOON AND EVENING...SLIGHT CHANCE ELSEWHERE...AS WEAK SHORT WAVE LIFTS THROUGH IN SW FLOW ALOFT. LONG RANGE MODELS TEND TO KEEP THE RIDGE JUST OFF THE EAST COAST...AND PREVENTING SYSTEMS FROM AFFECTING THE AREA MUCH. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... COLD FRONT IS NOW WORKING ITS WAY INTO HTS...AND WILL BE QUICK TO PLOW THROUGH THE TAF SITES OVER THE NEXT 4-6 HOURS. FROPA GENERATING WIND GUSTS OF 35KTS...AND INCLUDED THIS IN TEMPO GROUPS. WINDS WILL GUST CONTINUOUSLY TO 25-30KTS THROUGH THE FORECAST PERIOD AT ALL SITES. SNOW WILL SET UP BEHIND THE FRONT IN THE DAWN HOURS...AND WILL EVENTUALLY DROP VISIBILITIES TO IFR THROUGH THE COURSE OF TUESDAY. SOME BLOWING SNOW COULD BE EXPERIENCED AT EKN AND BKW. CEILINGS WILL DROP DOWN TO MVFR AS WELL. DO NOT EXPECT MUCH IMPROVEMENT BY 06Z WEDNESDAY. AVIATION OUTLOOK /BEYOND 06Z WEDNESDAY/ LIFR/IFR CONDITIONS AT TIMES IN SNOW SHOWERS OF VARYING INTENSITY THRU WEDNESDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WATCH FROM NOON EST TODAY THROUGH LATE WEDNESDAY NIGHT FOR WVZ035>038-046-047. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB NEAR TERM...29 SHORT TERM...RPY LONG TERM...DB AVIATION...26 oh AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 715 PM MST WED JAN 2 2008 .DISCUSSION...WINDY CONDITIONS PREVAIL EARLY THIS EVE ACRS THE SRN HALF OF ZONES. BASED ON 00Z NAM/RUC DATA...SFC GRADIENT CHANGES LITTLE OVER THE NEXT SEVERAL HOURS SO HAVE UPPED THE WINDS IN THE GRIDS/ZONES. GRADIENT DOES RELAX SOMEWHAT TOWARDS DAYBREAK AS SFC TROF WORKS INTO THE WRN DAKOTAS. HAVE ALSO UPPED SKY COVER A BIT ACRS OUR NRN ZONES WILL CIRRUS SPILLING THRU THE DIRTY RIDGE. LITTLE CHANGE TO TEMPS. && .AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH THURSDAY...WITH WINDY CONDITIONS OVERNIGHT GENERALLY SOUTH OF INTERSTATE 90. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ JOHNSON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 338 AM EST THU JAN 3 2008 .SHORT TERM...STRONG AREA OF SURFACE HIGH PRESSURE HAS BEGUN TO SLIDE EASTWARD AND IS CENTERED NEAR THE WESTERN PORTION OF TENNESSEE. DRY ARCTIC AIRMASS IS STILL PERSISTING OVER THE SOUTHEASTERN UNITED STATES. MAIN JET AXIS NOW ON THE DOWNSTREAM SIDE OF THE UPPER TROUGH ALONG THE ATLANTIC COAST RATHER THAN DIGGING INTO THE TROUGH...INDICATING DE-AMPLIFICATION OF STRONG PATTERN IS BEGINNING. COLDEST NIGHT YET AS DRIEST AIRMASS AND COLD AIR ADVECTION WITH NORTH TO NORTHWESTERLY FLOW HAS DROPPED MOST SITES INTO THE UPPER 20S AND LOWER 30S WITH DEW POINTS IN THE TEENS. GUIDANCE HAS BEEN HAVING A DIFFICULT TIME WITH THE CURRENT PATTERN AND FORECAST TEMPERATURES...AND HAVE GENERALLY BEEN TOO COOL. THE PROBLEM APPEARS TO BE FORECAST WINDS...AND GUIDANCE HAS BEEN SIGNIFICANTLY UNDERESTIMATING THE WINDS OVERNIGHT AND THE AMOUNT OF MIXING THAT IS TAKING PLACE. SMALLER SCALE MODELS SUCH AS THE NAM12 AND RUC13 HAVE BEEN DOING WELL IN PICKING UP THE PINCHED GRADIENT...ESPECIALLY ALONG THE COAST. THESE MODELS SHOW A SLIGHT INCREASE IN WINDS OVER THE NEXT FEW HOURS...AND CURRENT OBSERVATIONS SEEM TO BE ECHOING THIS TREND. THIS TREND ALSO SEEMS REASONABLE...GIVING COASTAL FLOW SLOWLY VEERING TO THE NORTHEAST AS THE SURFACE HIGH CONTINUES TO SHIFT...BRINGING IN WARMER MARITIME AIRMASS...WHICH COMPARED TO COLD CONTINENTAL AIRMASS SHOULD PROVIDE VERY LOCALIZED DENSITY DIFFERENCES THAT WOULD EVER SO SLIGHTLY INCREASE THE WINDS...ESPECIALLY NEAR THE COAST. AS A RESULT...ALTHOUGH IT WONT GO INTO THE OFFICIAL FORECAST...HAVE BUMPED UP THE MIN TEMPERATURES FOR THIS MORNING TO SHOW A BETTER TREND IN TEMPERATURES...AND DO NOT BELIEVE THAT MIN TEMPERATURE RECORDS WILL BE BROKEN THIS MORNING. WIND CHILLS WILL STILL MAKE TEMPERATURES FEEL AS THOUGH THEY ARE IN THE TEENS AND LOWER 20S THROUGH THE EARLY MORNING. STRATO-CU DECK HAS BEEN DRIFTING CLOSER TO OUR SOUTHERN MOST COASTAL COUNTIES. RADAR HAS INDICATED LIGHT RETURNS...ALTHOUGH THESE MAY NOT BE REACHING THE GROUND. HAVE BUMPED UP CLOUD WORDING A BIT ALONG THE NORTHEAST FLORIDA COAST TODAY TO REFLECT THIS. STILL FEEL THAT INCREASE IN LOW LEVEL MOISTURE AND COLD 850 MB TEMPS COULD PRODUCE VERY ISOLATED FLURRIES...MAINLY OVER SOUTHERN ST JOHNS AND FLAGLER COUNTIES...ALTHOUGH BEST CHANCES APPEAR TO BE JUST SOUTH OF OUR FORECAST AREA. THERE WILL BE VERY MINIMAL IMPACTS FROM THIS. WINDS WILL CONTINUE TO SHIFT TO THE NORTHEAST THROUGH THE DAY AS SURFACE HIGH PRESSURE SLIDES TO THE MID ATLANTIC COAST. THIS HIGH WILL FINALLY BEGIN TO WEAKEN AS UPPER PATTERN BECOMES MAINLY ZONAL. EXPECT BIGGEST IMPACTS ALONG OUR FLORIDA COASTAL COUNTIES WITH SLOW WARMING TREND AND SLIGHT INCREASE IN RELATIVE HUMIDITIES. BRIEF LAKE WIND ADVISORY CRITERIA MAY BE POSSIBLE THIS AFTERNOON ALONG THE IMMEDIATE COAST IN THESE AREAS...ALTHOUGH WILL HOLD OFF ON ANY ISSUANCE AT THIS TIME. BY THURSDAY NIGHT AND FRIDAY MORNING...DRY AIR ENHANCING RADIATIONAL COOLING WILL STILL KEEP TEMPERATURES OVER INLAND GEORGIA AND THE SUWANNEE VALLEY BELOW FREEZING...WHILE SOUTHERN MOST COASTAL COUNTIES WILL FINALLY REBOUND. FROST WILL BE POSSIBLE ALONG NORTHEAST FLORIDA COASTAL COUNTIES WHERE MOISTURE WILL INCREASE WHILE TEMPERATURES WILL STILL REMAIN COLD OVERNIGHT. LEFT HARD FREEZE WATCH AND FREEZE WATCH AS WATCHES...AS GUIDANCE HAS BEEN MUCH TOO COOL LATELY...AND WILL LET DAY SHIFT REEVALUATE AS NEW GUIDANCE AND DATA COMES IN. OTHERWISE...CURRENT HAZARDS APPEAR TO BE ON TRACK. FRIDAY AFTERNOON WILL CONTINUE WARMING TREND AS FLOW SHIFTS TO NORTHEAST TO EASTERLY AS HIGH PRESSURE CONTINUES TO WEAKEN AND SHIFT OFFSHORE OF THE MID ATLANTIC REGION. LOW LEVEL CONVERGENCE AND MINIMAL MOISTURE MAY BE ENOUGH TO PRODUCE SOME SPRINKLES OVER THE COASTAL WATERS AND THE IMMEDIATE COAST. SATURDAY WILL BE THE FINAL DAY OF BELOW NORMAL MINIMUM TEMPERATURES AS THE AREA OF HIGH PRESSURE WEAKENS FURTHER AND MOVES OVER THE OPEN ATLANTIC WATERS. .LONG TERM...SUNDAY THROUGH WEDNESDAY...HIGH PRESSURE CONTINUES TO SHIFT EASTWARD AHEAD OF A DEVELOPING AREA OF LOW PRESSURE OVER THE ROCKY MOUNTAINS. FLOW BETWEEN THE HIGH PRESSURE OFFSHORE AND APPROACHING LOW WILL BE FAVORABLE FOR WARM AIR ADVECTION...AND TEMPERATURES WILL GENERALLY BE ABOUT 10 DEGREES ABOVE NORMAL FOR LOWS AND HIGHS. BASICALLY A DRY FORECAST PERIOD...WITH THE NEXT FRONTAL BOUNDARY NOT EXPECTED TO REACH THE AREA BY LATE THURSDAY OR EARLY FRIDAY. && .AVIATION...WIND SHEAR WILL BE MAIN CONCERN AND WILL KEEP IN TAFS UNTIL 14Z. GUSTY WINDS WILL BE MORE NLY TODAY AND NOT QUITE AS STRONG AS YESTERDAY. MARITIME CLOUDS ARE EXPECTED TO DRIFT ONSHORE TONIGHT AND WILL INTRODUCE SCT DECK AT 2500 FT AFTER 03Z. && .MARINE...GALE FORCE GUSTS CONTINUE JUST NORTH OF AREA AND LIKELY EXTEND INTO THE GA OFFSHORE WATERS. SINCE ST. AUGUSTINE BUOY IS GUSTING TO NEAR GALE FORCE...HAVE EXTENDED THE GALE WRNG UNTIL 15Z. SCA CONDITIONS WILL PICK UP WHERE GALES LEAVE OFF AND CONTINUE UNTIL FRI AFTN WHEN PRES GRADIENT RELAXES. ONSHORE FLOW SETS UP FOR THE WEEKEND AND CONTINUES INTO EARLY NEXT WEEK. && .FIRE WEATHER...RELATIVE HUMIDITY WILL FALL INTO THE TEENS THIS AFTN ACROSS THE SUWANNEE VALLEY AND INLAND SE GA. MOISTURE WILL INCREASE IN THE FAR SE PORTION (SE OF SGJ TO PALATKA TO WEIRSDALE) WITH SLIGHT ONSHORE FLOW AND MIN RH MAY NOT FALL BELOW CRITICAL THRESHOLDS. REMAINDER OF AREA WILL IS UNDER A RED FLAG WRNG EXTREMELY LOW RH`S. && .PRELIMINARY POINT TEMPS/POPS... AMG 46 23 53 32 / 0 0 0 0 SSI 44 30 52 40 / 10 0 0 10 JAX 47 27 56 38 / 0 0 0 0 SGJ 48 37 57 47 / 10 10 20 0 GNV 48 26 59 40 / 0 0 0 0 OCF 49 31 60 44 / 0 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...HARD FREEZE WARNING UNTIL 10 AM EST THIS MORNING FOR ALACHUA- BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER-GILCHRIST- HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE-UNION. HARD FREEZE WATCH FROM THIS EVENING THROUGH FRIDAY MORNING FOR ALACHUA-BAKER-BRADFORD-COLUMBIA-GILCHRIST-HAMILTON-SUWANNEE- UNION. WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR DUVAL- FLAGLER-NASSAU-ST JOHNS. RED FLAG WARNING FROM 10 AM THIS MORNING TO 7 PM EST THIS EVENING FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL- GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-SUWANNEE-UNION. FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR CLAY- DUVAL-MARION-NASSAU-PUTNAM. WIND CHILL ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR CLAY- PUTNAM. GA...HARD FREEZE WARNING UNTIL 10 AM EST THIS MORNING FOR APPLING- ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN- COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE. RED FLAG WARNING FROM NOON TODAY TO 5 PM EST THIS AFTERNOON FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE- ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE- WAYNE. HARD FREEZE WATCH FROM THIS EVENING THROUGH FRIDAY MORNING FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE- ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE- WAYNE. AM...GALE WARNING UNTIL 10 AM EST THIS MORNING FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM-FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM-ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM. && $$ HURLBUT/TRABERT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1250 AM EST THU JAN 3 2008 .AVIATION (06 TAFS)... SFC RIDGING STARTING TO WORK DEEPER INTO THE REGION...THE LES IS STARING TO WANE. SCTD VFR CONDITIONS WITH MAINLY MVFR ACROSS THE AREA. -SHSN AND SOME LOWER CIGS AROUND 2.5 TO 3.5 K FT STILL AROUND THE SBN AND SOUTHERN MICHIGAN AREA...-SHSN WILL CONTINUE TO WEAKEN AND END BY 08-11Z. SKIES WILL CONTINUE TO SLOWLY CLEAR...WITH VFR EVERYWHERE AROUND 12-14Z. WINDS WILL INCREASE FROM THE SOUTH SOUTHWEST THIS MORNING INTO THE AFTERNOON WITH SOME GUSTS TO 20 KTS POSSIBLE. && .PREV DISCUSSION... /ISSUED 602 PM EST WED JAN 2 2008/ HYDROLOGY... MUCH WARMER WEATHER WILL RETURN THIS WEEKEND ALONG WITH THE CHANCE FOR RAIN. TEMPERATURES WELL INTO THE 40S ARE EXPECTED TO MELT MUCH OF THE SNOW EARLY NEXT WEEK. GIVEN CURRENT SOIL CONDITIONS...SNOW MELT AND EXPECTED RAINFALL...RIVER LEVELS ARE EXPECTED TO RISE SIGNIFICANTLY EARLY NEXT WEEK...WITH RIVER FLOODING LIKELY BY WEDNESDAY. PREV DISCUSSION... /ISSUED 447 PM EST WED JAN 2 2008/ SHORT TERM... TRICKY FORECAST ONCE AGAIN WITH THE MAIN CONCERNS BEING THE ONGOING LAKE EFFECT SNOW ACROSS NW PORTIONS OF THE FA AND LOW TEMPS/CLEARING TONIGHT. RUC 13...12Z NAM AND SREF HAVE BEEN HANDLING SHORT TERM/LAKE PROCESSES DECENT FOR THE MOST PART (WITH ADJUSTMENTS TO CURRENT OBS)...SO HAVE TRENDED FORECAST TO THEM. POTENT SHORELINE BAND OVER PORTIONS OF LA PORTE AND BERRIEN COUNTIES WILL CONTINUE TO SHIFT EAST THROUGH THE EVENING...AND WAIN IN THE PROCESS. NAM H925 OMEGA FIELDS CONTINUE TO SUPPORT TRANSITION FROM AN INTENSE SINGLE BAND TO MULTIPLE PARALLEL BANDS AS WINDS SHIFT MORE WESTERLY. GIVEN DECENT UPWARD VERTICAL VELOCITIES CENTERED JUST BELOW THE DENDRITIC GROWTH ZONE/STRONG LL CONVERGENCE IN PLACE INDICATED BY CONVERGENCE WIND SIGNATURE/COLLOCATION OF SFC SYNOPTIC TROUGH NEAR THE SOUTH END OF THE BAND/NAM BUFFER INDICATED LAKE INDUCED CAPE VALUES OF NEARLY 350 J/KG...EXPECT HEAVY TO MODERATE SNOW TO PERSIST THROUGH THE ADVISORY PERIOD. ADVISORY MAY HAVE TO EXTENDED INTO THE EVENING FOR BERRIEN AND ST JOSEPH COUNTIES AS MODELS MAY TO QUICK TO DIMINISH THE SNOW...ESPECIALLY WITH STRONG CONVERGENCE PRESENT PER 30 KNOT WINDS AT MICHIGAN CITY. BUT WITH EXTREMELY DRY MOVING IN UPSTREAM AND LOSS OF LAKE AGGREGATE PROCESSES PER LOSS OF FLOW OFF OF LAKE SUPERIOR...DIMINISHING TREND MAKES SENSE. WILL LET EVENING SHIFT RE-ASSES. CLEARING IS EXPECTED TONIGHT OVER WESTERN PORTIONS OF THE FA WILL ALLOW EXCELLENT RADIATIONAL COOLING AS WINDS DIMINISH. SNOW COVER IN PLACE WILL WILL ALLOW TEMPS TO DROP QUICKLY...WITH SOME AREAS FALLING BELOW ZERO F. HAVE LOWERED TEMPS WELL BELOW MOS TO REFLECT DRY AIR IN PLACE...AND POTENTIAL DROP PER DRY AIR ALOFT. CLOUDS OVER EASTERN PORTIONS OF THE FA MAY ALSO CLEAR AS LAKE PRECESS WILL BE THE SOLE CONTRIBUTION TO THE CLOUD FIELD TONIGHT. HAVE TRIED TO ADJUST CLOUD COVER TO H925 TRENDS...AND REFLECT THIS IN MINS. LOOK FOR CLEAR SKIES TOMORROW WITH COOL TEMPS ONCE AGAIN. HAVE UNDER CUT MOS GAIN DUE TO UPSTREAM TRENDS AND EXPECTED MIXING HEIGHTS. NW PORTIONS OF THE FA MAY SEE THE WARMER TEMPS AS WAA ENSUES AND ALLOWS RAPID THICKNESS INCREASES AND INCREASED LL FLOW. LONG TERM... THURSDAY NIGHT THROUGH WEDNESDAY...THE LONG WAVE TROF WILL BECOME REESTABLISHED OVER THE SOUTHWEST CONUS THIS WEEKEND...WITH AN AMPLIFYING RIDGE DOWNSTREAM OVER THE EASTERN CONUS. SMALLER SHORTWAVE TROFS WILL EJECT EAST OUT OF THE MAIN TROF...BRINGING THE CHANCE FOR PRECIPITATION STARTING SATURDAY. TEMPERATURES WILL GRADUALLY RISE ABOVE NORMAL AS SOUTH TO SOUTHWEST LOW LEVEL WINDS PERSIST. AREAS OF FOG WILL DEVELOP THIS WEEKEND AS LOW LEVEL MOISTURE INCREASES AND MOVES OVER SNOW COVERED AREAS. THE FOG WILL PROBABLY PERSIST TO AT LEAST SOME EXTENT UNTIL THE SNOW MELTS...CONSIDERING DEW POINT TEMPERATURES RISING TO NEAR 40F. HIGHS WILL BE TEMPERED BY SNOW COVER THROUGH THE WEEKEND...ESPECIALLY OVER NORTHERN AREAS WHERE SNOW COVER IS DEEPER AND WILL TAKE LONGER TO MELT. HAVE KEPT A CHANCE FOR RAIN FROM SATURDAY THROUGH TUESDAY AND ADDED A CHANCE FOR RAIN WEDNESDAY GIVEN SHORT WAVE TROFS MIGRATING NORTHEAST INTO THE GREAT LAKES REGION. A MAJOR TROF SHOULD MOVE EAST TUESDAY OR WEDNESDAY...AND BRING THE POTENTIAL FOR MORE RIVER FLOODING AS RUNOFF RAIN WATER COMBINES WITH RECENT SNOW MELT. THE GFS PER COMET/UCAR ENSEMBLE EXPERIMENTAL ANALYSIS CONTINUED TO INDICATE MUCH UNCERTAINTY TUESDAY INTO WEDNESDAY...SO CONFIDENCE IS LOW BY THE MIDDLE OF NEXT WEEK. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...SKIPPER AVIATION...SCHOTT in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1155 PM EST WED JAN 2 2008 .AVIATION...LAKE EFFECT SNOW SHOWERS WILL BE ON THE WANE FOR THE REMAINDER OF THE OVERNIGHT HOURS AS FLOW BACKS MORE WEST AND THEN SOUTHWEST WITH THE ARRIVAL OF LOW LEVEL RIDGING. EXPECT A MAINLY VFR STRATOCU DECK WILL HOLD FIRM FOR THE TAF SITES EARLY...GIVING WAY TO THICK JET-DRIVEN CIRRUS SHIELD FOR MUCH OF THE DAYLIGHT HOURS. ONE POSSIBLE ISSUE WILL BE POTENTIAL FOR STRATOCU DECK TO HANG TIGHT THROUGHOUT MUCH OF THE REGION INTO EARLY AFTERNOON AS DEVELOPING SOUTHWEST FLOW KICKS CLOUD DECK OFF OF LAKE MICHIGAN INLAND...THOUGH OVERALL CONFIDENCE ON THIS SCENARIO NOT HIGH...AND LIKELY ANY CEILINGS WOULD BE VFR. OTHERWISE...PRIMARY CONCERN FOR THE AFTERNOON WILL BE WIND...WITH TIGHTENING GRADIENT AND DECENTLY MIXED BOUNDARY LAYER RESULTING IN SOME RATHER GUSTY CONDITIONS FROM 18Z ONWARD. LAWRENCE && .UPDATE... /ISSUED 1057 PM EST WED JAN 2 2008/ NORTHWEST FLOW LAKE EFEFCT CONTINUES TO ROLL ON GIVEN INFLUX OF COLDEST AIRMASS OVER THE PAST SEVERAL HOURS (H85 TEMPS DIPPING TO ABOUT -18C PER RAOBS/RUC GUIDANCE) AND PASSAGE OF SUBTLE 700-500MB WAVE COUPLED WITH MORE THAN SUFFICIENT DEEP LAYER MOISTURE...AS 900-700MB RH CONTINUES TO HOLD ABOUT 85%. HOWEVER...CHANGES ON THE WAY LATE TONIGHT AS LOW LEVEL RIDGE AXIS ALREADY MAKING QUICK PROGRESS INTO THE U.P./UPPER MIDWEST...WITH OVERALL 1000-850 MB FLOW TURNING WEST AND THEN SOUTHWEST AND BEGINNING TO HAVE SOME SUBTLE EFFECT PER UPSTREAM MQT RADAR DEPICTING A SUBTLE SHIFT IN BANDING STRUCTURE. EXPECT THIS TREND WILL CONTINUE INTO THE EARLY MORNING HOURS...AS LOW LEVEL RIDGING TAKES OVER AND INVERSION HEIGHTS CRASH PER ARRIVAL OF 1000-500MB DEEP LAYER RIDGING AND SUBSEQUENT DRYING/LOSS OF MOISTURE ALOFT. IN TYPICAL LAKE EFFECT FASHION...ONGOING MOMENTUM OF SNOW BANDS LIKELY TO CARRY THE PRECIP A BIT LONGER THAN MODELS WOULD SUGGEST (ESPECIALLY WITH INITIAL SUPERIOR CONNECTION)...AND WILL THEREFORE HOLD ONTO HIGH POPS THROUGH ABOUT 09Z AS SHOULD SEE SOME BANDS CONTINUE BEFORE QUICKLY ERODING BY SUNRISE. LITTLE IN THE WAY OF ANY ADDITIONAL ACCUMULATIONS PER ONGOING LOSS OF MOISTURE SUPPORT...BUT PERHAPS UP TO AN INCH IF ANY BANDS CAN HOLD STILL LONG ENOUGH. TEMPERATURES OVERNIGHT QUITE IFFY. OVERALL HAVE RAISED GOING NUMBERS A TAD MOST SPOTS (MOST NOTICEABLE OVER NORTHWEST LOWER MICHIGAN WHERE ONSHORE FLOW WILL CONTINUE THROUGH THE NIGHT) AS EXPECT CLOUD COVER TO LINGER A BIT LONGER...AND UPSTREAM THICK JET-DRIVEN CIRRUS SHIELD WILL OVERSPREAD THE AREA AS WELL. HOWEVER...ALSO DEALING WITH EXCELLENT DRAINAGE FLOW OUT OF ONTARIO...WITH NUMBERS TUMBLING OVER EASTERN UPPER. EXPECT THIS SAME FLOW WILL EVENTUALLY BLEED OUT ACROSS LAKE HURON AND INTO NORTHERN LOWER...SO GOING NUMBERS AROUND 0 TO 5 LOOK A GOOD BET BY MORNING...BUT AGAIN WILL HAVE TO WATCH PROGRESSION OF CLOUDS AND POTENTIAL RELOCATION OF LAKE HURON STRATOCU DECK INTO NORTHEAST LOWER AS FLOW TRIES TO KICK NORTHEAST. UPDATED GRIDS/ZONES ALREADY OUT. LAWRENCE && DISCUSSION... /ISSUED 323 PM EST WED JAN 2 2008/ QUICK BURST OF LAKE EFFECT SNOW (LES) HAS PROGRESSED THRU EASTERN UPPER MI...AND IS ON TARGET TO DO THE SAME IN NORTHERN LOWER MI OVER THE NEXT SEVERAL HOURS. ARCTIC HIGH PRESSURE IN THE PLAINS WILL MOVE TO MO TONIGHT...AND TO KY/TN THURSDAY. RIDGE AXIS WILL CROSS MI EARLY THURSDAY MORNING...WITH STRONG WARM ADVECTION BY AFTERNOON AS SAID RIDGE MOVES EAST. PRECIP TRENDS THIS EVENING ARE THE MAIN FORECAST CONCERN. TONIGHT...SURFACE TROF AXIS NOW MOVING SOUTH ACROSS FAR NORTHERN LAKE MI...WITH A SMALL BULLSEYE OF MID LEVEL MOISTURE (850-700MB RH TO 90 PERCENT) ALONG FOR THE RIDE. THIS WILL BRING LES TO NW LOWER MI FROM LATE AFTERNOON THRU MID EVENING. PERIOD OF SYNOPTIC ASSISTANCE IS BRIEF...BY MIDNIGHT THE BETTER MOISTURE IS WELL DOWNSTATE...AND WE/RE FIGHTING OFF DRY AIR ADVECTION. GIVEN THE COMBINATION OF LOW LEVEL CONVERGENCE WITH THE TROF...DELTA T/S NEAR 20...AND MID LEVEL MOISTURE...ISOLATED BURSTS OF INCH/HR SNOWS IS POSSIBLE (AND OCCURRED IN LUCE CO AT MIDDAY). BUT THAT COMBINATION OF ELEMENTS WILL NOT LAST LONG AT ALL...AND BANDS WILL NOT GET A CHANCE TO GET ORGANIZED BEFORE THINGS START TO SHUT DOWN. SO WILL REDUCE SNOW ACCUMS A BIT FURTHER...WITH ONLY ISOLATED 2-INCH TOTALS POSSIBLE WEST OF I-75 IN THE LATE AFTERNOON/EVENING HOURS. FOR OVERNIGHT...INSTABILITY REMAINS PLENTY SUFFICIENT FOR VIGOROUS LES IN BORDERLINE NNW/NW FLOW. HOWEVER...MOISTURE IS FALLING OFF THE TABLE (850-700MB RH 50 PERCENT AT 06Z...40 PERCENT AT 09Z). PERHAPS MORE SIGNIFICANTLY...BIG RIDGING ARRIVES ON SUPERIOR AT 06Z...AND OUR WINDS WILL BE BACKING WEST TOWARD DAWN. THE LOSS OF THE SUPERIOR CONNECTION AND ARRIVAL OF ANTICYCLONIC FLOW WILL SPELL THE END OF LES. AND...IT/S WORTH NOTING THAT LES ON SUPERIOR NOW (BEHIND THE SURFACE TROF) IS LESS THAN IMPRESSIVE. END RESULT...JUST SCT LES IN THE SNOWBELTS OVERNIGHT...WITH MINIMAL ACCUMS. TEMPS OUTSIDE OF LES AREAS WILL AGAIN BE QUITE COLD...WITH SUB-ZERO READINGS LIKELY IN PLACES LIKE THE SAULT AND PLN. LAKE MI COASTAL LOCALES WILL SEE MINS CLOSER TO 10F. THURSDAY...BROAD RIDGING ALOFT WILL BE BUILDING ACROSS MID- CONTINENT. A SHORTWAVE EMBEDDED WITHIN THE RIDGE WILL PASS NORTH OF SUPERIOR DURING THE DAY. THIS COULD BRING SOME CLOUD COVER TO CHIPPEWA COUNTY...MAINLY DURING THE AFTERNOON. HOWEVER...WEDGE OF DRY AIR BETWEEN 900 AND 700MB SHOULD LIMIT CHANCE OF PRECIP REACHING THE GROUND (IF ANYTHING...MAYBE A FLURRY OR TWO AT MOST...AND WILL NOT INCLUDE IN THE FORECAST FOR NOW). OTHERWISE...INTENSE WARM ADVECTION WILL OCCUR...BUT MAINLY ABOVE 900MB. STILL RELATIVELY COOL (AND MOIST) AIR TRAPPED BELOW 900MB. SO WE WILL STAY COOLISH (NOT AS COLD AS TODAY) AND MAINLY CLOUDY (BETWEEN LOW CLOUDS...AND THE CIRRUS SHIELD HEADING OUR WAY FROM MANITOBA). MAX TEMPS WILL BE MAINLY IN THE 20S...NEAR 30 AROUND TVC...THOUGH A BRISK SOUTHWEST WIND WILL MAKE IT FEEL CHILLIER. SPEAKING OF WHICH...WILL ISSUE GALE WARNINGS FOR THE LAKE MI MARINE ZONES AND FOR WHITEFISH BAY FOR VERY LATE THURSDAY THRU FRIDAY MORNING...THANKS TO STRONG SW WINDS. ZOLTOWSKI REST OF THE FORECAST (THURSDAY NIGHT THROUGH NEXT WEDNESDAY)...PATTERN CHANGE STILL APPEARS TO BE ON TRACK OVER THE NEXT SEVERAL DAYS AS A DEEP WESTERN TROUGH FORCES DOWNSTREAM RIDGING ACROSS THE EAST COAST. THEREFORE...A WARMUP IS ON TAP LATER IN THE WEEKEND INTO EARLY NEXT WEEK. IN THE MEANTIME...MODERATING TEMPERATURES ARE EXPECTED TO ROUND OUT THE ABBREVIATED WORK WEEK INTO THE FIRST HALF OF THE WEEKEND. THE MAIN FORECAST CONCERNS WILL REVOLVE AROUND POPS THIS WEEKEND INTO NEXT WEEK AND JUST HOW WARM TEMPERATURES WILL GET. THURSDAY NIGHT INTO FRIDAY...UPPER LEVEL HEIGHTS WILL LEVEL OFF RESULTING IN A NEARLY ZONAL FLOW. MODEL CROSS SECTIONS/SOUNDINGS SHOW QUITE A BIT OF UPPER LEVEL MOISTURE BUT DRY MID AND LOWER LEVELS (MEAN 850-500 MB RH 35 TO 45 PERCENT) SO PARTLY CLOUDY SKIES SHOULD WORK. SOUTHWEST SURFACE FLOW WILL CONTINUE WITH PROGRESSIVELY MILDER AIR MOVING IN FROM THE SOUTH. THE BREEZE WILL KEEP TEMPERATURES FROM FALLING TOO MUCH THURSDAY NIGHT WITH LOWS IN THE TEENS TO LOWER 20S EXPECTED. GALES WILL CONTINUE ACROSS LAKE MICHIGAN ZONES ALONG WITH WHITEFISH BAY. HIGHS FRIDAY IN THE UPPER 20S TO LOWER 30S. FRIDAY NIGHT INTO SATURDAY...MODELS BEGIN TO DIVERGE JUST A BIT DURING THIS TIME PERIOD. THE GFS CONTINUES TO BRING A RIPPLE THROUGH THE FLOW WHICH SLOWS WARMUP JUST A TAD AS WELL AS POSSIBLY BRINGING IN A CHANCE OF SNOW OR RAIN SHOWERS. THE NAM/LAST NIGHTS ECMWF ARE MUCH MORE BULLISH WITH THE WARM AIR AND ARE MUCH DRIER. FOR NOW WILL CONTINUE WITH THE LOW CHANCE POPS AND ADD SNOW SHOWERS INTO THE RAIN SHOWERS AS GFS/UKMET WOULD BE COLD ENOUGH...ESPECIALLY IN THE MORNING TO SUPPORT THIS. LOWS FRIDAY NIGHT MAINLY IN THE 20S (WITH PERHAPS A FEW UPPER TEENS EAST). HIGHS SATURDAY IN THE MIDDLE TO PERHAPS UPPER 30S. SATURDAY NIGHT INTO SUNDAY...THE TROUGH CENTERED ACROSS THE WESTERN STATES CONTINUES TO AMPLIFY WHILE SENDING MINOR PIECES OF ENERGY NORTHEAST TOWARD THE REGION. WOULD NOT BE SURPRISED THOUGH IF THIS ENERGY REMAINS MAINLY TO OUR WEST BUT WILL CONTINUE WITH LOW CHANCE POPS TO MAINTAIN CONSISTENCY/LINE UP WITH SURROUNDING OFFICES. IN ADDITION...WITH WARMER AIR OVERRIDING THE SLOWLY MELTING SNOWPACK...WILL ADD IN AREAS OF FOG. LOWS SATURDAY NIGHT NOT FALLING TO MUCH FROM HIGHS ON SATURDAY (LOWER TO MIDDLE 30S) WITH HIGHS SUNDAY CREEPING UP INTO THE LOWER AND MIDDLE 40S. MONDAY AND TUESDAY...WESTERN TROUGH MOVES SLOWLY TO THE EAST BRINGING A BETTER CHANCE OF RAIN TO THE WESTERN GREAT LAKES. EXTENDED MODELS VARY AS TO THE TIMING/DEPTH OF SURFACE DEVELOPMENT BUT THERE IS THE POTENTIAL FOR A DECENT AMOUNT OF RAIN AT SOME POINT DURING THIS TIME WITH MORE FOG. THE SNOWMELT AND RAINFALL MAY EVENTUALLY LEAD TO HYDROLOGIC CONCERNS AS WELL. HIGHS IN THE 40S TO LOWER 50S. WEDNESDAY...TROUGH AXIS IS EXPECTED TO CREEP CLOSER TO THE REGION WITH MORE SEASONABLE AIR ARRIVING FROM THE NORTHWEST. WILL HAVE A CHANCE OF RAIN AND SNOW SHOWERS AS MOISTURE LINGERS BEHIND THE DEPARTING SYSTEM AND SURFACE COLD FRONT. NOT AS WARM WITH TEMPERATURES MAINLY IN THE 30S TO LOWER 40S. SULLIVAN && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING FROM 4 PM THURSDAY TO 10 AM EST FRIDAY FOR LMZ323- 341-342-344>346. LH...NONE. LS...GALE WARNING FROM 4 PM THURSDAY TO 10 AM EST FRIDAY FOR LSZ321. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 302 AM CST THU JAN 3 2008 .DISCUSSION... OVERALL TREND THIS FORECAST IS TO LOWER MAX TEMPERATURES OVER NEXT COUPLE OF DAYS. UPPER LEVEL RIDGE AXIS NOW OVER THE CNTRL CONUS WHILE COLD SFC HIGH PRESSURE HAS MOVED FAR TO OUR SOUTHEAST. STRONG RETURN FLOW ALREADY UNDERWAY THIS MORNING WITH STRONG 850MB WAA ADVECTION. SFC TEMPS HAVE BEEN SLOWLY RISING OVERNIGHT WHERE WINDS ARE GUSTING TO NEAR 25 MPH. DESPITE STRONG SWRLY 850MB WINDS TODAY...BUFKIT FORECAST SOUNDINGS OFF GFS/NAM/RUC SHOW INVERSION HOLDING STRONG WITH LITTLE TO NO MIXING BELOW 925 MB. SNOW COVER ACROSS ENTIRE FORECAST AREA WILL INHIBIT FULL HEATING POTENTIAL AS WELL SO HAVE BUMPED HIGHS DOWN BELOW MOS GUIDANCE AND THINK THE FREEZING MARK WILL BE A STRETCH AT MOST LOCATIONS TODAY. 850MB WAA CONTINUES INTO SATURDAY...WITH INVERSION HOLDING STRONG AT LEAST THROUGH FRIDAY. COULD SEE AN INCREASE IN MID AND HIGH CLOUDS FRIDAY AS WEAK VORT MAX MOVES THRU WHICH WOULD ALSO LIMIT HI TEMPS. AT SOME POINT...WITH ONGOING SNOW MELT AND AN INCREASE IN LLVL MOISTURE FM THE SOUTH...A STRATUS DECK WOULD BE EXPECTED TO DEVELOP. MODELS NOT LATCHING ONTO ANYTHING BUT AN AREA OF LOW CONDENSATION PRESSURE DEFICITS AT THE 925MB LAYER ACROSS MO AND SRN IA SAT MORNING. BEST CHANCE AT MIXING THRU THE INVERSION WILL BE ON SATURDAY AHEAD OF A SFC TROF...PROVIDED STRATUS DECK HAS NOT DEVELOPED OVER THE REGION. 850MB TEMPS ARE FORECAST AROUND +12C AND SO WL CONT HIGHS IN THE LOW 40S. HAVE BUMPED UP CLOUD COVER OVERNIGHT SATURDAY AND SUNDAY MORNING AS SUFFICIENT LLVL MOISTURE ADVECTION FM THE SOUTH AND RECENT SNOW MELT SHOULD HELP TO PRODUCE SOME STRATUS. SFC CDFNT WILL SWEEP THRU SUNDAY AFTERNOON WITH BOTH 00Z GFS/ECMWF IN GOOD AGREEMENT ON TIMING. BOTH MODELS GENERATE QPF TO OUR NORTH AND WEST BEHIND THE BOUNDARY LIKELY IN ASSOCIATION WITH UPPER SHORTWAVE ENERGY EJECTING OUT OF DEEP TROF ACROSS THE WESTERN CONUS. LOW POPS IN PREVIOUS FORECAST ALREADY ACCOUNT FOR THIS. EXTENDED PERIODS WILL BE CHALLENGING AS THE PROGRESSION OF THE UPPER LEVEL TROF ACROSS THE CENTRAL CONUS IS QUITE VARIABLE AMONG VARIOUS MODEL SOLUTIONS. MADE NO CHANGES TO PREVIOUS FORECAST. && .AVIATION...FOR TAF SITES KOFK/KLNK/KOMA WINDS ARE THE PRIMARY AVIATION CONCERN ACROSS EASTERN NEBRASKA AS VFR VSBYS/CIGS SHOULD PREVAIL THROUGH 12Z FRIDAY. PROFILER NETWORK WAS SHOWING 40KT SOUTH OR SOUTHWEST FLOW AT ABOUT 1500-2000FT OFF THE SURFACE...WITH SURFACE OBSERVATIONS RUNNING BETWEEN 10 AND 15KT. SURFACE WINDS SHOULD CONTINUE TO COME UP THROUGH THE MORNING...BUT SOME LOW LEVEL WIND SPEED SHEAR IS LIKELY AT TIMES THROUGH ABOUT 15Z OR 16Z. SURFACE WINDS SHOULD AVERAGE BETWEEN 15 AND 30KT DURING THE DAY BEFORE DROPPING OFF AFTER 00Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ GRIFFIS/DERGAN ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 235 AM CST THU JAN 3 2008 .DISCUSSION... FORECAST CHALLENGE CONCERNS EARLY WIND HEADLINES ALONG WITH TEMPERATURES. MODELS IN PRETTY CLOSE AGREEMENT THROUGH PERIOD AND WILL USE BLEND FOR FORECAST. INITIAL CONCERN IS ONGOING STRONG WIND AND HEADLINES. RUC SHOWING CORE OF LOW LEVEL JET CURRENTLY OVER VALLEY REGION AND SHIFTS FEATURE FAIRLY QUICKLY EAST AND OUT OF FA BY 12Z. WINDS IN DVL BASIN DOWN TO 15KT SO WILL MONITOR TRENDS. CURRENT THINKING IS THAT MAY BE ABLE TO CANCEL AT MORNING ISSUANCE BUT WILL SEE WHAT HAPPENS NEXT COUPLE OF HOURS. FOR REMAINDER OF DAY WARM ADVECTION NOT AS ROBUST AND GRADIENT RELAXES DURING COURSE OF DAY. LOOKS TO BE PLENTY OF MID/UPPER LEVEL CLOUDS FOR FILTERED SOLAR AT BEST. WITH MIXING TAILING OFF AND SHARP INVERSION WILL HOLD TEMPERATURES TOWARDS COOLER NUMERICAL GUIDANCE VALUES. WARMEST TEMPERATURES LIKELY TO BE IN HIGHER TERRAIN OVER WESTERN FA. GFS HINTING AT POSSIBLE ST DEVELOPMENT ACROSS FAR EAST AND SOUTHERN FA AS CONDENSATION PRESSURE DEFICITS AROUND 900-950 MB LOWER ALONG WITH ISENTROPIC LIFT. CONFIDENCE NOT HIGH ON FZDZ POTENTIAL BUT AM HESITANT TO PULL MENTION. WILL LEAVE GOING AND LET DAY SHIFT MONITOR TRENDS FOR ST DEVELOPMENT THIS AFTERNOON. DEGREE AND ALTITUDE OF CLOUD COVER TONIGHT WILL HAVE IMPACT ON MINIMUM TEMPERATURES. IF LOWER CIGS DO DEVELOP WILL SEE WARMEST MINIMUMS OVER SOUTH AND EAST AND WILL CONTINUE TREND. WARM ADVECTION INCREASES AGAIN FRIDAY AS THERMAL RIDGE SHIFTS EAST EDGING INTO FA. BOTH GFS AND NAM INDICATING SUFFICIENT MIXING HOWEVER SURFACE FLOW FROM S-SE DIRECTION...NOT FAVORABLE FOR SIGNIFICANT WARMING. FOR THIS WILL STAY CONSERVATIVE WITH MAXIMUM TEMPERATURES. THERMAL RIDGE SHIFTS OVER FA ON SATURDAY AND COULD WELL BE WARMEST DAY. BEST POTENTIAL LOOKS TO BE OVER WESTERN FA AS WINDS TURN MORE W-SW DURING AFTERNOON. WEAK COLD FRONT CROSSES FA SATURDAY NIGHT/SUNDAY. MOISTURE AVAILABILITY NOT VERY IMPRESSIVE SO WILL NOT EXPAND POPS. SYSTEM EARLY NEXT WEEK NOT QUITE AS IMPRESSIVE SO NOT PLANNING ON ANY MAJOR CHANGES TO LONGER RANGE. && .AVIATION... GRADIENT RELAXES DURING EARLY AM HOURS SO WINDS SHOULD DROP OFF SIGNIFICANTLY BY DAY BREAK. OTHERWISE LOOKING AT MAINLY MID/UPPER LEVEL CIGS. THERE IS SOME POTENTIAL FOR LOWER CIGS ACROSS FAR SOUTHERN AND EASTERN FORECAST AREA HOWEVER CONFIDENCE NOT VERY HIGH AT THIS POINT. IF LOWER CIGS DO DEVELOP MAY SEE SOME PATCHY FREEZING DRIZZLE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 331 AM CST THU JAN 3 2008 .SHORT TERM...TODAY THROUGH SATURDAY NIGHT THE 500 HPA RIDGE THAT HAS BEEN EXPECTED TO ARRIVE IS NOW MOVING INTO THE PLAINS...AND STRONG WARM ADVECTION HAS OCCURRED IN THE PAST SIX OR SO HOURS WITH SOUTHERLY 925 MB WINDS AS HIGH AS 60 TO 65 KNOTS IN SOME PLACES PER THE NAM/RUC SOUNDINGS. THIS HAS ASSISTED IN NEAR WIND ADVISORY CRITERIA WINDS ACROSS THE EASTERN CWA THIS MORNING WITH BRIEF STINTS AT KATY AND K8D3 OF 30 TO 35 MPH WINDS OBSERVED. EVEN AS THE AXIS OF STRONG WINDS ALOFT PUSHES TO THE EAST...KABR IS STILL OBSERVED TO RECORD 25 MPH WINDS IN BLOWING SNOW AT 0830Z. WITH WINDS STILL EXPECTED TO REMAIN ABOVE 15 KNOTS ACROSS THE EASTERN THIRD OF THE CWA THROUGH THE FIRST PART OF THE MORNING...EXTENDED THE BLOWING SNOW MENTION THROUGH 15Z IN THESE AREAS. IN ADDITION...A WIND ADVISORY REMAINS THROUGH 12Z. WINDS ARE CURRENTLY BELOW ADVISORY CRITERIA AT ALL STATIONS ACROSS THE EAST...BUT WITH THE STRONG WINDS STILL NOT FAR ABOVE THE SURFACE...30+ MPH WINDS ARE STILL POSSIBLE SO WILL LEAVE ADVISORY RUNNING THROUGH 6AM CST. A QUIET REMAINDER OF THE SHORT TERM IS STILL IN STORE WITH THE WARMER PACIFIC AIR STILL MAKING ITS WAY INTO THE NORTHERN PLAINS. NAM/RUC FORECAST SOUNDINGS INDICATE 850 HPA TEMPERATURES RISING TO +11 TO +13 C BY LATER THIS MORNING ACROSS THE CWA ON THE HEELS OF THE STRONG WARM ADVECTION...THEN DECREASING SOMEWHAT BUT REMAINING IN THE +5 TO +10 C RANGE THROUGH THE ENTIRE SHORT TERM. THUS...WARMER THAN NORMAL TEMPERATURES ARE EXPECTED OVER MOST OF THE AREA THE NEXT FEW DAYS. THE WARMEST DAY APPEARS TO BE SATURDAY...AS WINDS WILL BE RELATIVELY LIGHT TODAY AND FRIDAY WITH LIMITED MIXING...BUT MORE MIXING SHOULD OCCUR ON SATURDAY TO BRING DOWN STRONGER WINDS...LIMITING CLOUD POTENTIAL AND INCREASING THE POTENTIAL FOR WARMER TEMPERATURES. MET GUIDANCE SUGGESTS NEAR RECORD HIGH TEMPERATURES ON SATURDAY IN THE 40S AND 50S...PARTICULARLY IN THE WESTERN CWA...SO THIS WILL BE SOMETHING TO KEEP AN EYE ON FOR MAXIMUM TEMPERATURES. ACROSS THE EASTERN CWA...THERE IS STILL SOME INTEREST IN FOG POTENTIAL THIS EVENING THROUGH SATURDAY MORNING. 00Z NAM SOUNDINGS CONTINUE TO INDICATE STRONG WARM ADVECTION OVER THE SURFACE LEADING TO A DEEP LAYER ABOVE FREEZING ALOFT...BUT A LARGE INVERSION JUST ABOVE THE SURFACE WITH MOISTURE TRAPPED BENEATH IT DUE TO THE CURRENT SNOW COVER AS WELL AS MOISTURE ADVECTION FROM THE SOUTH. THE SOUNDINGS ALSO INDICATE WIDESPREAD LOW STRATUS/POSSIBLE FOG UNDER THE INVERSION...WITH TEMPERATURES AT THE SURFACE REMAINING RATHER COOL RELATIVE TO THE WARM AIR ALOFT. THE 00Z GFS IS SIMILAR IN SHOWING A VERY LARGE INVERSION...THOUGH IT IS NOT AS STRONG WITH THE WARM AIR ALOFT AND LOW LEVEL MOISTURE. HOWEVER...GIVEN THE COARSER RESOLUTION OF THE GFS IN THE BOUNDARY LAYER...NOT SURPRISED TO SEE THIS. THE NAM ALSO INDICATES LIGHT TO NO WINDS NEAR THE SURFACE UNDER THE INVERSION FOR MUCH OF THIS 36 HOUR TIME PERIOD FROM 00Z FRIDAY TO 12Z SATURDAY...AND OCCASIONALLY DEPICTS LITTLE TO NO WIND ALL THE WAY UP TO 800 HPA AS WELL. THOUGH THE GFS HAS A BIT STRONGER WINDS...POSSIBLY DUE IN PART TO THE COARSER BOUNDARY LAYER RESOLUTION...THINK THAT IF THE INVERSION DOES SET UP AS STRONG AS BOTH MODELS SUGGEST...EVEN IF THE WINDS ARE A BIT STRONGER THEY MAY SIMPLY FLOW OVER THE INVERSION WITH LITTLE AIR MOVEMENT AT THE SURFACE BELOW IT. THUS...FEEL IT IS A GOOD IDEA TO MENTION THE POSSIBILITY OF FOG IN THE GRIDS AT THIS POINT...EVEN THOUGH EXACT TIMING IS STILL RELATIVELY UNCLEAR. ANY FOG THAT WOULD FORM WOULD GREATLY INFLUENCE TEMPERATURES...AS WELL AS HELP MAINTAIN THE INVERSION...SO LOWERED HIGHS A BIT IN THE EAST TO ACCOUNT FOR THIS POSSIBILITY. ACROSS THE EAST ON SATURDAY...TEMPERATURES SHOULD BE ABLE TO RISE INTO THE 30S AND POSSIBLY 40S IN AREAS AS INCREASED MIXING LEADS TO STRONGER SURFACE WINDS...PREVENTING FOG POTENTIAL AND TAPPING INTO WARMER AIR ABOVE THE SURFACE. .LONG TERM...SUNDAY THROUGH WEDNESDAY MAIN CHALLENGE IN THE EXTENDED CONTINUES TO BE THE INCONSISTENCY BETWEEN MODEL SOLUTIONS. THE UPPER LEVEL PATTERN WILL START OFF FEATURING A BROAD TROUGH OVER THE WESTERN HALF OF THE COUNTRY...AND A RIDGE OVER THE EAST. THE GFS SLIDES THE TROUGH TO THE ROCKIES BY TUESDAY MORNING...THEN HAS IT MERGING WITH ANOTHER TROUGH TO THE NORTHWEST TUESDAY NIGHT AND BECOMING SITUATED OVER THE PLAINS ON WEDNESDAY. THE ECMWF IS MUCH FASTER...PUSHING THE TROUGH TO THE PLAINS BY TUESDAY MORNING...THEN QUICKLY EASTWARD AND NEVER MERGING WITH THE NEXT TROUGH...THOUGH THAT TROUGH DOES MOVE OVER THE PLAINS WEDNESDAY. AT THE SURFACE...GOOD AGREEMENT AMONGST THE MODELS OF A TROUGH OVER THE PLAINS EARLY SUNDAY AND WEAK HIGH PRESSURE BUILDING OVER THE AREA SUNDAY EVENING...AND THAT IS WHERE ANY REASONABLE AGREEMENT ENDS. THE GFS SHOWS A LOW PRESSURE SYSTEM TRACKING FROM EASTERN COLORADO SUNDAY EVENING TO WISCONSIN BY MONDAY EVENING...WITH PRECIPITATION OVER THE CWA MUCH OF MONDAY. THE ECMWF HAS A MUCH WEAKER FASTER MOVING LOW WITH LITTLE IN THE WAY OF PRECIPITATION. THE DIFFERENCES IN TIMING CONTINUES THROUGH THE END OF THE PERIOD AS THE ECMWF TRACKS HIGH PRESSURE ACROSS THE AREA ON WEDNESDAY AND THE GFS IS ABOUT 12 HOURS BEHIND. CURRENT MODEL DISCREPANCIES APPEAR TO GET EVEN WORSE PAST THE END OF THE LONG TERM PERIOD. SO...BASICALLY CHANGED VERY LITTLE IN THE EXTENDED WITH THE EXCEPTION OF PRECIPITATION SUNDAY NIGHT AND MONDAY. AFTER PERUSING THROUGH GFS FORECAST SOUNDINGS...IT APPEARS THERE WILL BE A FAIRLY DECENT LAYER OF WARM AIR ALOFT THAT COULD RESULT IN PRECIPITATION BEGINNING AS FREEZING RAIN SUNDAY NIGHT...AND HAVE SPREAD THAT CHANCE FURTHER WEST THAN THE PREVIOUS FORECAST INDICATED. SOUNDINGS ALSO INDICATING THE COOLER AIR TAKING OVER SOONER ON MONDAY...SO WENT WITH ALL SNOW IN THE NORTH AND A POSSIBLE MIX OF RAIN OR SNOW ACROSS THE SOUTH. BY MONDAY NIGHT...ANY CONTINUING PRECIPITATION SHOULD BE ALL SNOW. DRY CONDITIONS EXPECTED TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES IN BEHIND THE EXITING LOW. TEMPERATURES WILL STILL BE FAIRLY MILD ON SUNDAY AS WEAK WAA CONTINUES AND H85 TEMPS REMAIN JUST ABOVE ZERO. THE COOLER AIR BEGINS TO GET PULLED INTO THE REGION EARLY MONDAY...WITH H85 TEMPS IN THE SINGLE DIGITS BELOW ZERO FROM MONDAY EVENING ONWARD. WENT WITH A SLIGHT COOLING TREND MONDAY THROUGH WEDNESDAY...THOUGH TEMPS LOOK TO BE NEAR OR JUST ABOVE NORMAL. && .AVIATION... GUSTY SOUTH WINDS OF 20 TO 30 MPH WILL CONTINUE EARLY THIS MORNING FROM THE JAMES RIVER VALLEY EASTWARD...MAINLY AFFECTING KABR...KATY AND K8D3. VSBYS MAY FALL TO AROUND 2SM AT TIMES DUE TO BLOWING SNOW...MAINLY ALONG AND EAST OF INTERSTATE 29. THE STRONG WINDS...AND THE POTENTIAL FOR BLOWING SNOW... WILL SUBSIDE AFTER 12Z. VFR CONDITIONS WILL THEN PREVAIL ACROSS THE ENTIRE CWA WITH SCT- BKN HIGH CLOUDS AOA 20K FEET STREAMING ACROSS THE REGION. VSBYS WILL BE UNRESTRICTED. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...WIND ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR CLARK- CODINGTON-DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS. MN...WIND ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR BIG STONE- TRAVERSE. && $$ SHORT TERM...ECKSTEIN LONG TERM...PARKIN AVIATION...PARKIN WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO CA 445 AM PST THU JAN 3 2008 .DISCUSSION...RUNNING LATE AND WILL TRY AND KEEP THIS TO THE POINT. IN GENERAL VERY LITTLE CHANGE FROM PREVIOUS FORECASTS AND THINKING. HAVE UPGRADED THE HIGH WIND WATCH TO A WARNING STARTING AT NOON ALONG THE COAST FROM PIGEON POINT NORTHWARD AS WELL AS THE NORTH BAY HILLS. THE WARNING GOES INTO EFFECT AT 4 PM FOR THE REST OF THE CWA...THIS MAY BE A LITTLE EARLY BUT WANTING TO GIVE ADVANCE WARNING. THE NEXT EIGHT HOURS OR SO COULD APTLY BE LABELED THE CALM BEFORE THE STORM. IF YOU HAVEN`T TAKEN ACTION NOW SUCH AS TYING DOWN LOOSE ITEMS... CLEARING GUTTERS...ETC NOW IS YOUR LAST CHANCE. DOPPLER RADAR PICKING UP A FEW LIGHT RETURNS ALOFT THAT WILL ACT TO MOISTEN THE LOWER LEVELS. CURRENT SATELLITE AND WATER VAPOR SHOWS THAT THE FIRST FRONT OF INTEREST IS OUT NEAR 38N/130W. THIS IS ON THE SOUTHERN PERIPHERY OF THE STORM NOW MOVING TOWARDS THE COAST OF SOUTHERN CANADA. WATER VAPOR SHOWS THE SHORTWAVE OF INTEREST THAT WILL DRIVE THE BOUNDARY TOWARDS THE NORCAL COAST BY ABOUT MIDDAY TODAY. LATEST GFS/WRF AND RUC MODELS INDICATE STEADY LIGHT RAINS TO BEGIN AROUND THIS TIME. A FEW PRE-FRONTAL SCOUT SHOWERS WILL BE POSSIBLE AHEAD OF THIS. MODELS INDICATE THAT 60 KNOT WINDS ARE TO DEVELOP JUST ABOVE THE BOUNDARY LAYER AS EARLY AS THIS AFTERNOON. THEREFORE PUT THE HIGH WIND WARNING INTO EFFECT FROM PIGEON POINT NORTHWARD ALONG THE COAST AS WELL AS THE NORTH BAY HILLS BEGINNING AT NOON. NO DOUBT THE MAIN WIND EVENT WILL OCCUR WITH THE SECOND SYSTEM LATER TONIGHT. THE REAL INTERESTING WEATHER LOOKS TO OCCUR ROUGHLY FROM 06Z-20Z FRIDAY. DURING THIS PERIOD VERY STRONG WINDS AND HEAVY RAIN WILL OCCUR. THE FRIDAY MORNING COMMUTE WILL BE TREACHEROUS AT BEST. ONCE THE RAIN STARTS TONIGHT IT WILL BECOME VERY HEAVY IN THE HILLS. MODELS INSIST THAT AROUND 18Z FRIDAY A FINAL BURST OF VERY HEAVY RAIN SHOULD OCCUR...WITH RAINFALL RATES ON THE ORDER OF INCHES PER HOUR IN THE HEAVIEST LOCATIONS. ITS NOTED THAT NAM MODEL OUTPUT INDICATES NEARLY 20 MICROBARS OF LIFT AT 700 MB DURING THIS TIME...VERY IMPRESSIVE. SO NEEDLESS TO SAY THAT RAIN RATES ALONE WILL CAUSE HYDRO ISSUES ACROSS THE REGION WITH MINOR URBAN FLOODING LIKELY AS STORM DRAINS AND CULVERTS BACK-UP. THE STRONG WINDS MAY BE OF GREATER CONCERN WITH ONE OF THE STRONGER AND MORE WIDESPREAD WIND EVENTS THAT WEVE SEEN IN QUITE SOME TIME. ANY WEAKENED TREES OR POWER LINES WILL BE SUSCEPTIBLE TONIGHT THROUGH FRIDAY TO FALLING OVER. POWER OUTAGES SHOULD BE EXPECTED. A COOL SHOWERY REGIME WILL CONTINUE OVER THE WEEKEND WITH LOWERING SNOW LEVEL EVEN ACROSS THE BAY AREA. VERY LITTLE CHANGE TO THE EXTENDED GRID PACKAGE. FINALLY...FOLKS PLANNING TRAVEL TO THE SIERRA SHOULD PLAN ACCORDINGLY. TRAVEL TO AND FROM THERE WILL BE NEAR IMPOSSIBLE BY THIS EVENING. IT WOULD SEEM LIKELY THAT ALL THE TRANS-SIERRA PASSES WILL BE CLOSED FOR LONG PERIODS OF TIME FOR THE NEXT SEVERAL DAYS. EVEN FOLKS PLANNING ACTIVITIES IN THE BAY AREA HILLS SHOULD PLAN FOR SEVERE WINTER WEATHER CONDITIONS. && .AVIATION...CLOUDS ARE INCREASING AS A COLD FRONT APPROACHES THE BAY AREA TERMINALS. MVFR CONDITIONS ARE CURRENTLY BEING REPORTED AT SFO...OAK AND STS. TERMINALS TO THE SOUTH WILL MAINTAIN VFR CONDITIONS THROUGH 00Z AT WHICH POINT CIGS WILL BECOME MVFR. SOUTHERLY WINDS WILL BE AN ISSUE FOR ALL SAN FRANCISCO BAY TERMINALS THIS AFTERNOON AND ARE EXPECTED TO BE REACH 25 KTS WITH GUSTS INTO THE MID 30S. THE DISTRICT WILL ALSO SEE MODERATE TO HEAVY RAIN BEGINNING EARLY THIS AFTERNOON AND LASTING THROUGH TOMORROW. && .MARINE...A HIGH SURF ADVISORY HAS BEEN ISSUED FOR ALL OF OUR COASTLINE FOR THURSDAY AND FRIDAY. WAVE MODEL FORECASTS SHOW W-NW SWELL INCREASING OVER THE NEXT THREE DAYS...PARTICULARLY ON SATURDAY WHEN W-NW SWELL PEAK 28-30 FEET RANGE WITH PERIODS OF 16 SECONDS. IF THE MODELS CONTINUE TO SHOW THIS HIGH SWELL IN LATER FORECASTS THEN THE HIGH SURF ADVISORY WILL BE UPGRADED TO A WARNING AT A LATER TIME. A COASTAL FLOOD WATCH HAS ALSO BEEN ISSUED FOR THIS TIME PERIOD AS THE HIGH SURF...WINDS AND TIDES WILL LIKELY CAUSE COASTAL FLOODING IN FLOOD-PRONE AREAS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDA....GALE WARNING ALL WATERS BY THIS EVENING WITH ROUGH BAR. .TDA....HIGH WIND WARNING ENTIRE SAN FRANCISCO AND MONTEREY BAY AREAS THIS AFTERNOON THROUGH FRIDAY AFTERNOON. ....COASTAL FLOOD WATCH AND HIGH SURF ADVY THIS AFTERNOON THROUGH FRI AFTERNOON FROM SONOMA COUNTY THRU MONTEREY COUNTY. && $$ PUBLIC FORECAST: WALBRUN AVIATION/MARINE: LARRY NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 345 AM MST THU JAN 3 2008 .SHORT TERM... (TODAY AND TONIGHT) SHORT TERM CONCERNS INCLUDE TEMPERATURES ALONG WITH PRECIP CHANCES ACROSS THE CONTINENTAL DIVIDE TONIGHT. CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING MODERATE WEST TO SOUTHWEST FLOW ACROSS THE STATE WITH FASTER ZONAL FLOW AND AN EMBEDDED SHORT WAVE MOVING ACROSS THE NORTHERN ROCKIES ATTM. WATER VAPOR IMAGERY ALSO INDICATING ANOTHER SHORT WAVE MOVING ONSHORE ACROSS THE SOUTHERN CALIF COAST WITH AMPLE MID AND UPPER LEVEL MOISTURE STREAMING OUT AHEAD OF THE SYSTEM INTO THE DESERT SW ATTM. AT THE SFC...LEE TROUGHING CONTINUES TO DEEPEN ACROSS THE I-25 CORRIDOR KEEPING TEMPS ALL OVER THE BOARD ACROSS THE REGION...WITH CURRENT READINGS IN THE 30S AND 40S ACROSS THE EASTERN MTS AND IMMEDIATE PLAINS...TEENS AND 20S ACROSS THE REST OF THE HIGHER TERRAIN AND IN THE SINGLE DIGITS ACROSS THE LOWER ARKANSAS RIVER VALLEY AND ONLY IN THE SINGLE DIGITS BELOW ZERO ACROSS THE SAN LUIS VALLEY ATTM. TODAY...EMBEDDED SHORT WAVE ACROSS THE NORTHERN ROCKIES CONTINUES ACROSS THE NORTHERN HIGH PLAINS...WITH LEE TROUGHING PUSHING ACROSS THE EASTERN PLAINS IN RESPONSE...WHICH LOOKS TO FINALLY SCOUR OUT THE COOL AIR PERSISTING ACROSS THE LOWER ARKANSAS RIVER VALLEY WITH HIGHS SLOWLY CLIMBING INTO THE MID 40S TO LOWER 50S. TOUGH CALL ON TEMPS ACROSS THE LOWER EASTERN SLOPES AND IMMEDIATE PLAINS WITH THE VERY MILD IN PLACE ATTM...THOUGH WILL SLOWLY DECREASING DOWNSLOPE FLOW AND INCREASING MID AND HIGH LEVEL CLOUDS FROM WEST TO EAST...HAVE GONE WITH HIGHS IN THE MID TO UPPER 50S...WITH 30S TO MID 40S ACROSS THE REST OF THE HIGHER TERRAIN. AGAIN TOUGH CALL ON HIGHS IN THE SAN LUIS VALLEY WITH INCREASING HIGH CLOUDS HAMPERING GOOD MIXING AND HAVE KEPT HIGHS IN THE MID 20S TO LOWER 30S. TONIGHT...FLOW ALOFT BECOMES MORE SOUTHWEST AS SOUTHERN CALIF SHORT WAVE CONTINUES ACROSS THE DESERT SOUTHWEST AND NOSES INTO THE FOUR CORNERS REGION BY 12Z. MOISTURE AND UVV CONTINUE TO INCREASE ACROSS WESTERN COLORADO AHEAD OF SYSTEM AND HAVE INCREASED POPS WITH BEST CHANCES OF MEASURABLE PRECIP ACROSS THE SW MTS AFTER MIDNIGHT. LEE TROUGHING REDEVELOPS AND STRENGTHENS ACROSS THE I-25 CORRIDOR KEEPING OVERNIGHT LOWS QUITE MILD AGAIN ACROSS THE LOWER EASTERN SLOPES AND IMMEDIATE PLAINS. -MW .LONG TERM... (FRIDAY THROUGH WEDNESDAY) ...PROLONGED SNOW...HEAVY AT TIMES...EVENT CONTINENTAL DIVIDE SATURDAY THROUGH MONDAY... ...BREEZY-WINDY AND MILD/WARM EAST OF CONTINENTAL DIVIDE FRIDAY-SUNDAY... FRIDAY THROUGH MONDAY...ENSEMBLE DATA CONTINUES TO PROJECT WEST- SOUTHWESTERLY CHINOOK(SNOW-EATER) MIDDLE TO UPPER LEVEL FLOW PATTERN FRIDAY THROUGH AT LEAST MONDAY. THIS WOULD PROMOTE MILD/WARM TEMPERATURES ACROSS MUCH OF SOUTHERN CO...ESPECIALLY ALONG THE I-25 CORRIDOR AND SOUTHEAST CO PLAINS FRIDAY THROUGH SUNDAY. THERE IS SOME MODEL DIVERGENCE WITH A SYSTEM DEVELOPING NEAR CO ON MONDAY. ONE RUN-TO-RUN MODEL CONSISTENCY IS PARTS OF THE CONTINENTAL DIVIDE GETTING HAMMERED BY SNOW...MAINLY THE HIGHER TERRAIN. LATEST WATER VAPOR SATELLITE IMAGERY SHOWED A COUPLE OF MOISTURE SOURCE REGIONS...ONE NORTHEAST OF HAWAII AND ANOTHER SOUTHEAST OF HAWAII. SATELLITE DERIVED TOTAL PRECIPITABLE WATER INDICES HAD THESE AREAS FAIRLY MOIST. THIS COULD BE A MOSTLY PROLONGED OROGRAPHIC DRIVEN EVENT FOR THE CONTINENTAL DIVIDE HIGHER TERRAIN WITH TOTAL SNOWFALL OF 1 TO 3 FEET...ESPECIALLY FOR FAVORED OROGRAPHIC AREAS LIKE WOLF CREEK...CUMBRES PASS...AND MONARCH PASS TO NAME A FEW...SATURDAY THROUGH SUNDAY. THERE COULD BE MORE SNOWFALL SUNDAY NIGHT AND MONDAY. WEST-SOUTHWEST WINDS OF 15 TO 35 MPH WITH POTENTIAL GUSTS UP TO 55 MPH WOULD CREATE BLOWING AND DRIFTING SNOW AND MAKING FOR HORRENDOUS MOUNTAIN TRAVEL CONDITIONS AROUND THE CONTINENTAL DIVIDE. SOUTHWEST FLOW DOES NOT PROMOTE THE GREATEST OROGRAPHIC COMPONENT FOR THE LA GARITA AND SAWATCH MOUNTAIN RANGES...BUT THERE ARE BOUTS OF WESTERLY FLOW THAT WOULD INCREASE THE SNOWFALL POTENTIAL FOR THOSE AREA. PLAN TO HOLD OFF ISSUING A WINTER STORM WATCH...BUT WILL HIGHLIGHT THE HIGH IMPACT WINTER CONDITIONS IN THE HAZARDOUS WEATHER OUTLOOK AND CR NEWS OF THE DAY STORY. EAST OF THE CONTINENTAL DIVIDE...THE COMBINATION OF VIGOROUS MOUNTAIN TOP FLOW AND STEEPENING MIDLEVEL LAPSE RATES SHOULD SUPPORT BREEZY-WINDY CONDITIONS...POSSIBLY VERY WINDY ACROSS OUR EASTERN CO MOUNTAIN TOPS...FRIDAY THROUGH SUNDAY. EVEN THE SAN LUIS VALLEY COULD SEE BREEZY CONDITIONS EACH DAY BRINGING MAXIMUM TEMPERATURES INTO THE 30S CLOSE TO 40F. LOWER TERRAIN SNOWPACK SHOULD DISSIPATE QUICKLY EACH DAY GIVEN THE WEST- SOUTHWEST CHINOOK FLOW. 700MB TEMPERATURES OF 0C TO +3C COULD TAKE MAXIMUM TEMPERATURES INTO THE 60S ACROSS SOUTHEAST CO FRIDAY AND SATURDAY. MINIMUM TEMPERATURES WILL BE A CHALLENGE GIVEN A STRONG THERMAL /BANANA- BELT/ INVERSION GENERALLY AT 6K-9K FT MSL JUST WEST OF I-25 CORRIDOR TOWARDS THE MOUNTAINS. TUESDAY AND WEDNESDAY...NO CHANGES TO CURRENT FORECAST. METZE && .AVIATION... VFR CONDITIONS EXPECTED TO PERSIST FOR TAF SITES THROUGH TONIGHT...THOUGH WILL CONTINUE TO SEE INCREASING MID AND HIGH LEVEL CLOUD COVER THROUGH THE DAY TODAY. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 1035 AM EST THU JAN 3 2008 .SYNOPSIS... A LARGE ARCTIC HIGH PRESSURE WILL BUILD INTO THE REGION THIS AFTERNOON...AND CREST TO OUR SOUTH LATE TONIGHT. THIS HIGH WILL THEN TRANSFORM INTO A BERMUDA TYPE HIGH...WHICH IS A VERY UNUSUAL EVENT FOR THIS TIME OF YEAR. AS IT PARKS OFF THE EASTERN SEABOARD...IT WILL SLOWLY BUT SURELY SEND A SOUTHWESTERLY FLOW OF INCREASINGLY MILD AIR OUR WAY AS HEAD INTO THE WEEKEND. TEMPERATURES WILL MODERATE BACK TO ABOVE NORMAL READINGS BY SUNDAY. && .NEAR TERM /UNTIL 6 PM THURSDAY/... A 1041 MB ARCTIC SFC HIGH PER THE LATEST RUC13 OUTPUT IS MOVING FROM ERN LAKE ONTARIO OVER UPSTATE NY. THE FRIGID AIR MASS WILL ONLY BE SHORT LIVED THOUGH. HOWEVER...TEMPS THIS MORNING WERE A LITTLE COLDER THAN THE FORECAST AND WE HAVE LOWERED MAX TEMP TODAY /ABOUT 3 DEGREES ACROSS THE FCST AREA OR SO/ TO ONLY REACH 10 DEGREES IN THE CAPITAL REGION...AND LOWER TEENS IN THE MID HUDSON VALLEY. THE HILLS AND MTNS WILL ONLY BE IN THE SINGLE DIGITS DESPITE SUNNY CONDITIONS. THE 12 KALB SOUNDING IS A CLASSIC ARCTIC SOUNDING. THE INVERSION IS DOWN BELOW 4 KFT...HENCE IT WILL BE HARD TO BREAK 10 DEGREES AT KALB. THE WIND CHILLS WILL CONTINUE TO DECREASE...BUT STILL A 5-10 MPH WIND WILL PRODUCE WIND CHILLS ABOUT 5 TO 15 DEGREES BELOW ZERO PRIOR TO NOON. && .SHORT TERM /6 PM THURSDAY THROUGH SATURDAY/... TONIGHT...WE STILL BELIEVE WITH AN INITIALLY MOSTLY CLEAR SKY AND LITTLE OR NO WIND...TEMPERATURES WILL DROP FAST OVER THE EXTENSIVE SNOW PACK. WE STILL FEEL MOST MOS NOS ARE NOT COLD ENOUGH AND GENERALLY DO NOT RESOLVE SKIN TEMPERATURES WELL...ESPECIALLY WHEN WARM ADVECTION COMMENCES ALOFT. IT LOOKS LIKE HIGH AND MID LEVEL CLOUDS...THE RESULT OF THE FIRST THRUST OF WARM AIR ADVECTION...ASSOCIATED WITH A WEAK SHORT WAVE..WILL ARRIVE AROUND 06Z. IF THESE CLOUDS ARE DELAYED A BIT LONGER...OUR PROJECTED LOW TEMPERATURES ARE PROBABLY GOING TO NOT BE COLD ENOUGH. WITH THE WARM AIR ADVECTION CLOUDS...AND LITTLE BIT MORE MOISTURE...IT WOULD NOT TAKE MUCH FORCING TO RING A LITTLE ICE CRYSTAL ACTION OUT OF THE CLOUDS ACROSS OUR HIGHER TERRAIN TO THE NORTH. WILL KEEP LOW/SLIGHT CHANCES OF SNOW SHOWER ACTIVITY IN THOSE AREAS TONIGHT. TOMORROW...AS THE FIRST SURGE OF WARM AIR ADVECTION PASSES BY...HIGH PRESSURE WILL START SPRAWLING TO OUR SOUTH...HEIGHTS ALOFT BEGIN TO RISE...AND H850 TEMPERATURES CONTINUE TO WARM SLIGHTLY TO ABOUT -8C. WHAT WE HAVE NOTICED IN THE PAST...IS THAT MOS NOS USUALLY WARM THE SURFACE TOO FAST DURING THE WINTER MONTHS (ESPECIALLY WHEN THERE IS A SNOW PACK). HOWEVER...LOOKING AT THE MODEL SOUNDINGS SUGGEST THE USUAL STRONG INVERSION WILL NOT BE PRESENT...IN FACT...THE COLUMN LOOKS TO MIX PRETTY WELL. STILL...WITH -8C OR SO H850 HPA TEMPS AND THE SNOW PACK...STILL FEEL TEMPERATURES WILL NOT GET QUITE AS HIGH AS MOS MAV NOS INDICATE SO WENT A COUPLE DEGREES BELOW THEM. NEVERTHELESS...TEMPERATURES WELL INTO THE 20S WILL BE A MARKED IMPROVEMENT COMPARED TO TODAY`S FRIGID READINGS. TEMPERATURES WILL OBVIOUSLY FALL BACK FRIDAY NIGHT...BUT NOTHING LIKE THE PAST SEVERAL NIGHTS. WE MIGHT HOLD ONTO A SLIGHT BREEZE IN MOST PLACES...ALONG WITH SOME HIGH/MID LEVEL CLOUDS WHICH SHOULD KEEP TEMPS FROM FREE FALLING. FOR NOW...ACCEPTED THE MAV NOS WHICH LOOK REASONABLE. BY SATURDAY...A SOUTHWESTERLY FLOW WILL BRING FURTHER MODERATION BUT NOT DRAMATIC YET. SHOULD ENJOY YET ANOTHER DRY DAY...ALTHOUGH BY DAY`S END CLOUDS FROM THE NEXT DISTURBANCE MIGHT TEND TO THICKEN. && .LONG TERM /00Z SUNDAY THROUGH WEDNESDAY/... THIS PERIOD WILL BE SIGNIFIED BY A FEW BOUTS OF WARM ADVECTION PRECIP (LIGHT) AND TEMPERATURES CLIMBING ABOVE NORMAL. JUST HOW MUCH THE BOUNDARY LAYER WILL RESPOND TO THIS WARM ADVECTION REMAINS TO BE SEEN (FROZEN GROUND WITH SNOW COVER). STILL APPEARS THAT 50+ DEGREE WEATHER INTO THE VALLEY LOCATIONS FOR NEXT WEEK. THE INITIAL SHOT OF WARM ADVECTION ARRIVES SATURDAY NIGHT ACCOMPANIED BY WEAK SHORT WAVE. THIS SHOULD BE ENOUGH TO KEEP THE LOW CHANCE POPS FOR WINTRY MIXTURE. THICKNESS SCHEMES AND BUFR FILES SHOW A DISCONNECT IN THE MOISTURE PROFILE WITH THE CHANCE FOR LIGHT SNOW/SLEET/FZRA(DZ). SO WILL CONTINUE WITH THE FORECAST MIXTURE AT THIS TIME. BEYOND THIS TIME FRAME...IT SEEMS THE MODEL QPF/S SHOW LITTLE AND INTERMITTENT BOUTS OF SOME PRECIP BUT FEEL PROBABILITIES ARE TOO LOW TO WARRANT PRECIP CHANCES AT THIS TIME. THE NEXT SHOT OF ORGANIZED PRECIP ARRIVES DURING THE MIDDLE PART OF NEXT WEEK WITH TIMING DIFFERENCES REMAINING. ALTHOUGH...AHEAD OF THIS FEATURE...IMPRESSIVE WARM UP EXPECTED WITH 850MB TEMPS CLIMBING TO AROUND +10C! AGAIN JUST HOW MUCH OF THIS WARMTH IS REALIZED NEAR THE GROUND REMAINS TO BE SEEN AND WILL CONTINUE TO ADVERTISE TEMPS WELL INTO THE 50S FOR VALLEY LOCATIONS. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS WILL CONTINUE THROUGH THIS FORECAST CYCLE AS MAIN LAKE EFFECT ACTIVITY REMAINS WEST OF THE REGION AND WEAKENING. MID AND HIGH LEVEL MOISTURE ARRIVES TONIGHT...SIGNIFYING A PATTERN CHANGE HEADING INTO THE WEEKEND. WINDS WILL BE GUSTY TODAY FROM A NORTHERLY DIRECTION BUT QUICKLY DIMINISH THIS EVENING. OUTLOOK... FRI-SAT...VFR...WITH NO SIG WX AT THIS TIME. SAT NT-SUN...MVFR...POTENTIAL FOR -DZ...-FZDZ (NOCTURNAL CONCERN). MON...VFR...POTENTIAL FOR MVFR FOR CIGS. && .HYDROLOGY... NO MAJOR HYDROLOGY CONCERNS THE NEXT COUPLE OF DAYS AS TEMPERATURES WILL BE WELL BELOW FREEZING LIKELY CAUSING SIGNIFICANT ICE BUILD UP. HOWEVER...A DRAMATIC WARM UP IS EXPECTED LATE THIS WEEKEND AND INTO THE FIRST HALF OF NEXT WEEK. THIS MAY POTENTIALLY CAUSE NOT ONLY MELTING AND RIVER RISES...BUT ICE JAM CONCERNS ARE EXPECTED TO INCREASE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...TAW/HWJIV NEAR TERM...TAW SHORT TERM...HWJIV LONG TERM...BGM AVIATION...BGM HYDROLOGY...BGM WWW.WEATHER.GOV/ALBANY ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1020 AM EST THU JAN 3 2008 .UPDATE...LATEST RUC ANALYSIS THIS MORNING REVEALS THE MID LEVEL RIDGE AXIS CENTERED ALMOST DIRECTLY OVER THE NORTH-SOUTH AXIS OF THE EASTERN SHORE OF LAKE MICHIGAN. LIGHT AND VARIABLE WINDS ARE STARTING TO TURN SOUTHERLY NEAR THE LAKE MICHIGAN SHORELINE WITH THE ARRIVAL OF THIS AXIS. THE SCATTERED SNOW SHOWER ACTIVITY FROM OVERNIGHT HAS DWINDLED TO NOTHING MORE THAN FLURRIES...AFFECTING AREAS ALONG THE LAKE MICHIGAN SHORELINE...INTO AREAS AROUND THE STRAITS. A SECONDARY AREA OF FLURRIES OR VERY LIGHT SNOW SHOWERS IS MOVING NORTHEAST ACROSS IN THE VICINITY OF GRAND RAPIDS. HOWEVER...LAST FEW RADAR SCANS HAS SHOWN A WEAKENING TREND. THIS SHOULD CONTINUE TO BE THE CASE AS IT LOSES ANY HELP FROM UPSLOPE FLOW. THE NAM AND GFS KEEP ENOUGH SHALLOW INSTABILITY AROUND INTO THE EARLY AFTERNOON HOURS TO KEEP INVERSION HEIGHTS AROUND 3KFT AROUND LAKE MICHIGAN. THUS...SOME SCATTERED FLURRIES CANNOT BE RULED OUT INTO THE EARLY AFTERNOON HOURS FOR LOCATIONS ALONG THE SHORELINE...STRETCHING NORTHWARD INTO EASTERN UPPER MICHIGAN. FINALLY...BY MID TO LATE AFTERNOON...ANTICYCLONIC FLOW WILL TAKE OVER...AND WE SHOULD JUST BE LEFT WITH SOME VERY SHALLOW LAKE CLOUDS NEAR THE LAKE MICHIGAN SHORELINE. IN THE MEANTIME...MID LEVEL CLOUDS ON THE BACK SIDE OF THE RIDGE AXIS ARE ALREADY INVADING NORTHERN MICHIGAN THIS MORNING AND WILL OVERTAKE THE AREA BY MIDDAY. THUS...WILL BUMP UP SKY COVER A BIT TO REFLECT MOSTLY CLOUDY SKIES FOR THE REMAINDER OF THE DAY AS VERY LITTLE SUN WILL BE SEEN. IN ASSOCIATION WITH INCREASING CLOUD COVER...HIGH TEMPERATURES WILL ALSO BE BUMPED DOWN A FEW DEGREES IN MOST PLACES. WE SHOULD STILL SEE TEMPERATURES CLIMB INTO THE LOWER TO MIDDLE 20S...WITH PERHAPS SOME UPPER 20S NEAR THE LAKE MICHIGAN SHORELINE. OVERALL...FAIRLY CLOSE TO SEASONAL HIGH TEMPERATURES FOR EARLY JANUARY. NOW TAKING A LOOK AT WINDS. THE MIXED LAYER OFF THE 12Z MODELS THIS MORNING STILL CONTAIN 40 TO 45 KNOT WINDS. WINDS DROP OFF AS YOU HEAD FURTHER SOUTH...SO WILL KEEP THE ADVISORY AS IT APPEARS. GALES STILL LOOK GOOD AS WELL...SO NO CHANGES PLANNED FOR ANY OF THE HEADLINES. WILL MAKE A MENTION OF PATCHY BLOWING SNOW IN THE AREAS WHICH SAW 1 TO 3 INCHES OF VERY LIGHT FLUFFY SNOW LAST NIGHT...WHICH INCLUDES NORTHWEST LOWER MICHIGAN...MAINLY NORTH OF M-72...AND ACROSS EASTERN UPPER MICHIGAN. THE NATURE OF THE SNOW WILL ALLOW IT TO BLOW AROUND THIS AFTERNOON. KAS && .AVIATION... /ISSUED 655 AM EST THU JAN 3 2008/ A CORE OF WINDS AROUND 5000 FEET WILL APPROACH 50 KNOTS WILL AFFECT ALL OF THE TAF SITES THIS AFTERNOON AND TONIGHT, BUT PLN AND APN WILL BE THE MOST AFFECTED WITH WIND GUSTS AT THE SFC TO NEAR 35 KNOTS POSSIBLE. OTHERWISE, THE LAKE EFFECT SNOW THAT WAS AFFECTING TVC HAS MOVED NORTH IN PLN AND WAS DIMINISHING TO JUST FLURRIES. MOST IF NOT ALL OF THE SNOW IS EXPECTED TO HAVE STOPPED BY 15Z. LUTZ && .PREV DISCUSSION... /ISSUED 422 AM EST THU JAN 3 2008/ DISCUSSION...1000-850 MB WIND RIDGE AXIS IS NOW THROUGH MOST OF N LOWER IS BEGINNING TO MAKE ITS PRESENCE KNOWN WITH THE SNOW BANDS. WHILE MAINTAINING SOME NW FLOW CHARACTERISTICS, THE SNOW BANDS ARE BEGINNING TO MOVE TO THE NE PER THE APX 88D RADAR. MOST OF THE SNOW IS VERY LIGHT ATTM AS WELL. THE MAIN SFC RIDGE IS TO THE EAST OF THE REGION, AND 500 MB IS STILL TO THE WEST. HOWEVER, THE NEXT 850 MB TROUGH NORTH OF LAKE WINNIPEG, HAS A LLJ MAX OF 65 KNOTS THE TAIL OF WHICH IS AROUND 50 KNOTS AND IS HEADED TOWARD N MICHIGAN. THIS WILL BE THE MAIN CONCERN OF THE FORECAST PACKAGE. TODAY/TONIGHT/FRIDAY...FIRST THE FLURRIES WILL COME TO AN END AS THE DRY AIR IN THE 850-700 MB LAYER CONTINUES TO PLUMMET TO LESS THAN 30% AND THE WINDS TURN SW BY 15Z. THEN AROUND 18Z THE 850 MB JET CORE WILL BEGIN TO TRANSIT THE REGION. THE GFS SHOW 45KT AT 00Z WHILE THE NAM IS AROUND 50KT. HAVE GONE WITH THE SREF AT THE SFC WHICH IS SLIGHTLY LESS THAN 1/2 OF THE 850 MB WINDS AND GUSTS TO AROUND 45 MPH. THIS LOOKS TO BEGIN TO WIND DOWN AROUND 06Z, AS BOTH MODELS SLOW THE WIND DOWN TO THE 30 KNOT RANGE BY 12Z. THE GALES ON THE LAKES LOOK LIKE THEY WILL PROBABLY BE END AROUND 12Z, BUT WILL LEAVE THE 15Z END TIME ON FRIDAY FOR SOME ERROR. OTHERWISE AS THE WINDS WIND DOWN THE SW WIND WILL WARM THE REGION AND THE TEMPERATURES WILL BE IN THE LOWER 30S. SO MINIMAL MELTING LOOKS TO TAKE PLACE. FRIDAY NIGHT...TEMPERATURES FALL OFF TO THE MID 20S OVERNIGHT. THE SOUNDINGS ARE SATURATED FROM THE SFC TO 900 MB, HOWEVER, THE MOISTURE DOESN`T INCREASE WITH HEIGHT. THERE MAY BE A BIT OF FOG, BUT THIS DOESN`T LOOK LIKELY UNTIL... SATURDAY...TEMPERATURES START OUT IN THE 20S, BUT RAPIDLY WARM TO ABOVE FREEZING BY 18Z, THE SW FLOW CONTINUES TO NOT ONLY WARM, BUT MOISTURE LOWER LEVELS AS THE SOUNDINGS BEGIN TO SHOW A PROFILE WHERE THE MOISTURE INCREASE WITH HEIGHT. WITH ALL OF THE DRY AIR AT 850 MB AND UP, IT LOOKS LIKE THAT DRIZZLE BECOMES MORE AND MORE PREVALENT, AND I THINK THAT THE MOISTURE IN THE LOWER LEVELS ARE BEING UNDERPLAYED AS THE SNOW BEGINS TO MELT. SATURDAY NIGHT/SUNDAY...I BECOME MORE CONVINCED THAT DRIZZLE WILL BE THE MAIN HYDROMETEOR, AS THE DRY AIR ALOFT IN THE SOUNDINGS IS IMPRESSIVE, BUT THE MOISTURE IN THE LOWER LEVELS CONTINUE TO SHOW MOISTURE INCREASING WITH HEIGHT AND THERE IS WIND SHEAR (DIRECTIONAL AND SPEED) AS WELL TO HELP THE COLLISION PROCESS. MONDAY AND BEYOND...IT WILL BE INTERESTING TO SEE HOW MUCH SNOW IS LEFT AROUND HERE BY TUESDAY AS THE TEMPERATURES WARM TO THE MID 40S. HOWEVER, RAIN LOOKS MORE LIKELY NOW BY THE END OF MONDAY AS THE SOUNDINGS BECOME SATURATED. BY THE END OF TUESDAY, THE FRONT LOOKS LIKE IT IS THROUGH AND THE PROFILES COOL AND DRY. THIS SETS THE STAGE FOR WHETHER THERE WILL BE SNOW ON WEDNESDAY OR THURSDAY OF NEXT WEEK. DAY 6 MAY NEED SOME ADJUSTMENT IF THE GFS IS RIGHT AND DAY 7 (THURSDAY) MAY HAVE THE SNOW. LUTZ && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 1 AM EST FRIDAY FOR MIZ008-015>025. LM...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST FRIDAY FOR LMZ323-341-342-344>346. LH...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST FRIDAY FOR LHZ345>349. LS...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST FRIDAY FOR LSZ321-322. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 625 AM EST THU JAN 3 2008 UPDATED AVIATION SECTION FOR 12Z TAFS .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER NAMERICA WITH A RIDGE OVER MUCH OF THE PLAINS AND ROCKIES AND A TROF OVER THE EAST COAST. A STRONG SHORTWAVE WAS RIDING OVER THE WRN CONUS RIDGE THROUGH CENTRAL CANADA WITH 00Z RAOBS INDICATING 12 HR 5H PRES FALLS IN EXCESS OF 180M AHEAD OF THIS FEATURE. A STRONG WAA PATTERN HAS DEVELOPED AHEAD OF THIS SHORTWAVE PRODUCING A LARGE AREA OF MID-HIGH CLOUDS ACROSS CNTRL CANADA INTO THE NRN PLAINS. AT THE SFC...A HIGH PRES RIDGE EXTENDS FROM WESTERN GREAT LAKES SOUTH THROUGH THE CENTRAL AND SOUTHERN PLAINS WHILE A DEEP 992 MB SFC LOW IS APPROACHING HUDSON BAY. THE RESULTING STRONG SRLY GRAIDENT HAS PRODUCED SOUTHERLY WIND GUSTS IN EXCESS OF 30KT OVER A LARGE AREA EARLY THIS MORNING...FROM SRN MANITOBA AND NRN ONTARIO INTO THE NRN PLAINS STATES. LES HAS GENERALLY DISSIPATED OVER ERN LAKE SUPERIOR PER THE MQT RADAR LOOP WITH WARMER AND DRIER AIR ADVECTING INTO THE REGION. && .DISCUSSION... MAIN FCST ISSUE WILL BE STRONG WINDS TODAY WITH TIGHTENING PRES GRADIENT BTWN DEPARTED STRONG SFC HIGH PRES RIDGE AND LOW PRES TRACKING TOWARD HUDSON BAY. MODELS FORECASTING STRONG JET 65-70 KT CORE MOVING ACROSS UPPER MICHIGAN LATE THIS MORNING AND AFTERNOON WHICH SEEMS REASONABLE BASED ON UPSTREAM 00Z SOUNDINGS OVER THE NRN PLAINS AND SCNTRL CANADA. WAA PATTERN ASSOC WITH THE JET CORE WILL BE MOVING OVER A SHALLOW EXITING ARCTIC AIRMASS WHICH WILL INHIBIT MIXING AT LEAST INITIALLY TODAY. HOWEVER...MODELS SNDGS STILL PRETTY CONSISTENT INDICATING MIXING TO NEAR 950 MB BY LATE MORNING/AFTERNOON WHICH SHOULD ALLOW FAIRLY STRONG SRLY WIND GUSTS OF 40 TO 45 KT TO SFC...ESPECIALLY FOR DOWNSLOPING AREAS ALONG THE LAKE SUPERIOR SHORELINE AND EXPOSED HIGHER TERRAIN LOCATIONS. ANOTHER FACTOR SUPPORTING/ENHANCED SW WINDS WILL BE THE STRONG SFC PRES FALLS OF NEARLY 10MB/3HR SPREADING E ACROSS ONTARIO THU AHEAD OF ADVANCING SFC LOW. THUS...HAVE ISSUED A WIND ADVISORY FOR ALL COUNTIES ALONG LAKE SUPERIOR AND DOWNSTREAM OF LAKE MI...WHICH INCLUDES ALL BUT SRN HOUGHTON...IRON...DICKINSON AND MENONIMEE. GALE WARNINGS ARE ALSO POSTED FOR ALL OF LAKE SUPERIOR OPEN WATERS AND ALL OF THE NEARSHORE AREAS EXCEPT OVER HURON AND KEWEENAW BAYS AS MIXING WILL BE EVEN MORE VIGOROUS OVER UNSTABLE MARINE AREAS. MIXING TO NEAR 950 MB YIELDED HIGH TEMPS NEAR GFS MOS GUIDANCE...MID 20S INLAND TO UPR 20S ALONG GREAT LAKES SHORELINES. TONIGHT THROUGH SATURDAY...GRADIENT SLACKENS WINDS AS WINDS EVENTUALLY DECOUPLE BY LATE EVENING. SHOULD STILL BE ENOUGH OF A BOUNDARY LYR WIND (5-15 KTS) OVERNIGHT TO PREVENT TEMPS FROM FALLING MUCH.STUCK CLOSE TO GFS GUIDANCE MINS WITH LOWS IN MID TEENS INTERIOR WEST TO UPR TEENS/LOWER 20S ELSEWHERE. WENT WITH DRY WX GRIDS ALL THE WAY THROUGH SATURDAY AS THERE IS LITTLE AVAILABLE MOISTURE AND WEAK FORCING AT BEST OVER THE CWA. HIGH TEMPS WILL GRADUALLY WARM ABV FREEZING BY THE WEEKEND WITH MID TO UPR 30S EXPECTED FOR SATURDAY. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... LIGHT SOUTHWEST WINDS INCREASE SIGNIFICANTLY BY LATE MORNING. WINDS MAY GUST TO 40 KT ONCE INVERSION BEGINS TO BREAK. THE STRONG WINDS...ALONG WITH NEWLY FALLEN SNOW...ALLOWS FOR POTENTIAL OF BLOWING SNOW AND REDUCED VISIBILITIES 15Z TO 00Z. FOR THE MOST PART...VIS SHOULD REMAIN ABOVE 5SM IN THE BLSN. NEXT SHOT AT LOWER CLOUDS WILL ARRIVE LATE TONIGHT AS MOISTURE INCREASES BELOW 5KFT. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... TIGHT PRES GRADIENT DEVELOPING BTWN DEPARTING STRONG SFC HIGH PRES RIDGE AND LOW PRES TRACKING E TO HUDSON BAY RESULTS IN VERY STRONG WINDS ACROSS LK SUPERIOR NEXT 18 HR. AFTER THAT IT IS FAIRLY QUIET ON INTO EARLY NEXT WEEK WITH WINDS STAYING BLO 30 KT. BACK TO TODAY. SETUP IMPRESSIVE FOR A HIGH END GALE. AIRMASS IS NOT FULLY STABLE OVER LAKE SUPERIOR AND IMPRESSIVE PRESSURE FALLS SPREADING ACROSS ONTARIO HELP TO ENHANCE S TO SW WINDS. GUSTS TO 50 KNOTS BTWN THE KEWEENAW AND ISLE ROYALE ARE POSSIBLE THROUGH MID AFTN BUT SEEMS TOO LOCALIZED TO GO WITH STORM WARNING. WINDS DIMINISH QUICKLY THIS EVENING AS PRESSURE GRADIENT RELAXES. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST THIS EVENING FOR MIZ006-007-013-014-085. WIND ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING TO 5 PM EST/4 PM CST/ THIS AFTERNOON FOR MIZ001>003-009. WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM EST THIS EVENING FOR MIZ004-005. LAKE SUPERIOR... GALE WARNING FROM 8 AM THIS MORNING TO 9 PM EST THIS EVENING FOR LSZ266-267. GALE WARNING FROM 8 AM THIS MORNING TO 7 PM EST THIS EVENING FOR LSZ265. GALE WARNING UNTIL 9 PM EST THIS EVENING FOR LSZ263-264. GALE WARNING FROM 8 AM THIS MORNING TO 7 PM EST THIS EVENING FOR LSZ249>251. LAKE MICHIGAN...GALE WARNING FROM 8 AM THIS MORNING TO 1 AM EST FRIDAY FOR LMZ221-248-250. && $$ SYNOPSIS/DISCUSSION...VOSS AVIATION/MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1045 AM EST THU JAN 3 2008 .SYNOPSIS...HIGH PRESSURE AND A COLD...DRY AIR MASS WILL REMAIN THROUGH TONIGHT. AS THE CENTER OF THE LARGE HIGH DRIFTS SLOWLY EAST...TEMPERATURES WILL BEGIN TO WARM. BY THE START OF NEXT WEEK...HIGH TEMPERATURES SHOULD BE WELL INTO THE 60S. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1045 AM THURSDAY...1000-850MB THICKNESSES WERE COLD...AND BOTH THE NAM AND THE RUC SHOW THESE THICKNESSES TO ONLY RISE TO AROUND 1265M OR SO BY 00Z. THIS WOULD SUPPORT READINGS ONLY IN THE UPPER 20S. HOWEVER...GIVEN THE DEGREE OF RISE UNDER FULL SUN THIS MORNING...AND SLIGHTLY WARMER 850MB TEMPERATURES VERSUS 12Z WEDNESDAY...HIGH TEMPERATURES SHOULD REACH THE 30S...THOUGH IT WILL OFTEN FEEL LIKE IT IS IN THE 20S. LITTLE CHANGE TO THE GRIDDED AND WORDED FORECAST TEMPERATURES...AND WHERE MODIFIED THE CHANGE WAS DOWN A DEGREE OR TWO. DEW POINTS SHOULD REMAIN MOSTLY IN THE SINGLE FIGURES...LEADING TO A DRY DAY WITH MINIMUM RELATIVE HUMIDITY VALUES AROUND 25 PERCENT. 925MB WINDS FROM 15-25KT EARLY THIS MORNING...STRONGEST IN THE EAST... WILL DIMINISH TO 10-15KT BY 00Z. GIVEN THE NEARLY DRY ADIABATIC LOW-LEVEL LAPSE RATES...SURFACE WINDS AROUND 10 MPH IN THE WEST... TO 10 TO 20 MPH IN THE EAST WITH A BETTER POTENTIAL FOR A GUST THERE AT TIMES...SHOULD BE THE RULE. RALEIGH PROFILER SHOWED A WIND AROUND 15KT JUST OFF OF THE SURFACE DURING MID- MORNING...WHICH BLENDS NICELY WITH THE RANGE OF WIND SPEEDS EXPECTED FROM WEST TO EAST THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... AS OF 115 AM THURSDAY...THE COLDEST TEMPERATURES THIS FORECAST SERIES COMES TONIGHT WITH THE SURFACE HIGH AND A VERY DRY AIRMASS CENTERING OVER THE AREA AND MAXIMUM RADIATIONAL COOLING. LOWS IN THE TEENS ARE LIKELY. AIRMASS MODERATION SHOULD BEGIN WITH RIDGING ALOFT ON FRI...850 TEMPERATURES RISING ABOVE 0C IN WSW FLOW... AND LOW LEVEL THICKNESS APPROACHING 1310M. SKIES SHOULD BE MOSTLY SUNNY WITH CIRRUS STREAKS FROM THE WEST. SUNSHINE SHOULD WARM THE SURFACE TEMPERATURES INTO THE MID TO UPPER 40S. FRI NIGHT-SAT...MODELS SHOW WIDESPREAD SATURATION ABOVE THE 500 MB LEVEL WITH THE APPROACH OF A SHORT WAVE AND DEFORMATION IN WESTERLY FLOW FROM THE RED RIVER VALLEY. RESULTING CIRRUS SHOULD SLIGHTLY REDUCE THE DIURNAL TEMPERATURE RANGE WITH LOWS MAINLY MID TO UPPER 20S AND HIGHS 50-55. -RFG && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 115 AM THURSDAY...SURFACE HIGH PRESSURE PUSHES OFF THE EAST COAST AND AN UPPER LONG WAVE TROUGH DEEPENS OVER THE WEST DURING THE WEEKEND. THIS SETS THE STAGE FOR MASSIVE RIDGING ALONG THE EAST COAST WITH 500 MB HEIGHTS EXCEEDING 582 DM MON AND TUE. BY WED... GFS IS SLOWER BY 12-24 HOURS FROM THE ECMWF SHOWING EASTWARD PROGRESS OF A COLD FRONT BEING PUSHED BY A STRONG WAVE CURRENTLY EMBEDDED IN A 190KT JET SOUTHWEST OF THE ALEUTIANS. SAT NIGHT-SUN...A MINOR SHORT WAVE TRACKS ACROSS THE AREA IN WESTERLY FLOW ALOFT GENERATING CIRRUS AND HIGHER MID CLOUDS IN AN OTHERWISE STABLE DRY AIRMASS. THE FORECAST SOUNDING SUGGESTS SOME OROGRAPHIC STANDING WAVE ENHANCEMENT OF HIGHER CLOUDINESS THAT COULD INHIBIT RADIATIONAL EFFECTS. OTHERWISE MODEL THICKNESS SUPPORTS HIGHS AROUND 60 AFTER MORNING LOWS IN THE MID 30S. SUN NIGHT-TUE...FLOW AROUND THE PERIPHERY OF THE BERMUDA HIGH BRINGS A MORE MARITIME CHARACTER TO THE AIR WITH INCREASING LOW LEVEL MOISTURE. FOR THIS TIME OF YEAR...THE PATTERN TYPE SUGGESTS WIDESPREAD EARLY MORNING FOG. THE AIRMASS GRADUALLY DESTABILIZES TO ALLOW SOME GROWTH OF STRATOCUMULUS TUE. OTHERWISE MOSTLY CLEAR. LOW LEVEL THICKNESS REACHES THE 1360S WITH POTENTIAL FOR HIGHS REACHING MID 60S TO AROUND 70 AFTER MINIMUMS IN THE 40S. TUE NIGHT-WED...CLOUDINESS SHOULD BE ON THE INCREASING IN CONFLUENT PREFRONTAL SOUTHERLY FLOW AND MINIMUMS WILL LIKELY REMAIN ABOVE 50 BEFORE TRANSITIONAL TEMPERATURES WITH A CHANGE IN AIRMASS ON WED.N A COMPROMISE BETWEEN GFS AND ECMWF SUPPORTS A CHANCE OF SHOWERS ON WED. -RFG && .AVIATION /16Z THURSDAY THROUGH MONDAY/... AS OF 1045 AM THURSDAY...VFR CONDITIONS EXPECTED ACROSS THE TAF AREA THROUGH THE PERIOD. CLEAR SKIES WILL PREVAIL. SURFACE WINDS WILL BE MORE GUSTY AT EASTERN TAF SITES...TOWARD KRWI AND KFAY... BUT ONLY TO AROUND 20KT AT BEST EXPECTED THIS AFTERNOON. WINDS SHOULD DROP TO CALM AROUND OR NOT LONG AFTER SUNSET. VFR CONDITIONS ARE GENERALLY EXPECTED ON FRIDAY AND SATURDAY. HIGH PRESSURE WILL REMAIN OVERHEAD FRIDAY INTO EARLY SATURDAY ...THEN MOVE OFFSHORE DURING THE DAY. THIS OFFSHORE MOVEMENT WILL ALLOW WINDS TO SHIFT TO THE SOUTHEAST AND SOUTH... RETURNING MOISTURE TO THE REGION SUNDAY INTO MONDAY. THERE IS A POSSIBILITY OF SOME MVFR CONDITIONS FOR SUNDAY INTO MONDAY ACCORDING TO SOUNDING DATA. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...RFG LONG TERM...RFG AVIATION...DJF/RHJ nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 602 AM CST THU JAN 3 2008 .UPDATE... UPDATED THE FORECAST TO ALLOW THE WIND ADVISORY TO EXPIRE. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH SATURDAY NIGHT THE 500 HPA RIDGE THAT HAS BEEN EXPECTED TO ARRIVE IS NOW MOVING INTO THE PLAINS...AND STRONG WARM ADVECTION HAS OCCURRED IN THE PAST SIX OR SO HOURS WITH SOUTHERLY 925 MB WINDS AS HIGH AS 60 TO 65 KNOTS IN SOME PLACES PER THE NAM/RUC SOUNDINGS. THIS HAS ASSISTED IN NEAR WIND ADVISORY CRITERIA WINDS ACROSS THE EASTERN CWA THIS MORNING WITH BRIEF STINTS AT KATY AND K8D3 OF 30 TO 35 MPH WINDS OBSERVED. EVEN AS THE AXIS OF STRONG WINDS ALOFT PUSHES TO THE EAST...KABR IS STILL OBSERVED TO RECORD 25 MPH WINDS IN BLOWING SNOW AT 0830Z. WITH WINDS STILL EXPECTED TO REMAIN ABOVE 15 KNOTS ACROSS THE EASTERN THIRD OF THE CWA THROUGH THE FIRST PART OF THE MORNING...EXTENDED THE BLOWING SNOW MENTION THROUGH 15Z IN THESE AREAS. IN ADDITION...A WIND ADVISORY REMAINS THROUGH 12Z. WINDS ARE CURRENTLY BELOW ADVISORY CRITERIA AT ALL STATIONS ACROSS THE EAST...BUT WITH THE STRONG WINDS STILL NOT FAR ABOVE THE SURFACE...30+ MPH WINDS ARE STILL POSSIBLE SO WILL LEAVE ADVISORY RUNNING THROUGH 6AM CST. A QUIET REMAINDER OF THE SHORT TERM IS STILL IN STORE WITH THE WARMER PACIFIC AIR STILL MAKING ITS WAY INTO THE NORTHERN PLAINS. NAM/RUC FORECAST SOUNDINGS INDICATE 850 HPA TEMPERATURES RISING TO +11 TO +13 C BY LATER THIS MORNING ACROSS THE CWA ON THE HEELS OF THE STRONG WARM ADVECTION...THEN DECREASING SOMEWHAT BUT REMAINING IN THE +5 TO +10 C RANGE THROUGH THE ENTIRE SHORT TERM. THUS...WARMER THAN NORMAL TEMPERATURES ARE EXPECTED OVER MOST OF THE AREA THE NEXT FEW DAYS. THE WARMEST DAY APPEARS TO BE SATURDAY...AS WINDS WILL BE RELATIVELY LIGHT TODAY AND FRIDAY WITH LIMITED MIXING...BUT MORE MIXING SHOULD OCCUR ON SATURDAY TO BRING DOWN STRONGER WINDS...LIMITING CLOUD POTENTIAL AND INCREASING THE POTENTIAL FOR WARMER TEMPERATURES. MET GUIDANCE SUGGESTS NEAR RECORD HIGH TEMPERATURES ON SATURDAY IN THE 40S AND 50S...PARTICULARLY IN THE WESTERN CWA...SO THIS WILL BE SOMETHING TO KEEP AN EYE ON FOR MAXIMUM TEMPERATURES. ACROSS THE EASTERN CWA...THERE IS STILL SOME INTEREST IN FOG POTENTIAL THIS EVENING THROUGH SATURDAY MORNING. 00Z NAM SOUNDINGS CONTINUE TO INDICATE STRONG WARM ADVECTION OVER THE SURFACE LEADING TO A DEEP LAYER ABOVE FREEZING ALOFT...BUT A LARGE INVERSION JUST ABOVE THE SURFACE WITH MOISTURE TRAPPED BENEATH IT DUE TO THE CURRENT SNOW COVER AS WELL AS MOISTURE ADVECTION FROM THE SOUTH. THE SOUNDINGS ALSO INDICATE WIDESPREAD LOW STRATUS/POSSIBLE FOG UNDER THE INVERSION...WITH TEMPERATURES AT THE SURFACE REMAINING RATHER COOL RELATIVE TO THE WARM AIR ALOFT. THE 00Z GFS IS SIMILAR IN SHOWING A VERY LARGE INVERSION...THOUGH IT IS NOT AS STRONG WITH THE WARM AIR ALOFT AND LOW LEVEL MOISTURE. HOWEVER...GIVEN THE COARSER RESOLUTION OF THE GFS IN THE BOUNDARY LAYER...NOT SURPRISED TO SEE THIS. THE NAM ALSO INDICATES LIGHT TO NO WINDS NEAR THE SURFACE UNDER THE INVERSION FOR MUCH OF THIS 36 HOUR TIME PERIOD FROM 00Z FRIDAY TO 12Z SATURDAY...AND OCCASIONALLY DEPICTS LITTLE TO NO WIND ALL THE WAY UP TO 800 HPA AS WELL. THOUGH THE GFS HAS A BIT STRONGER WINDS...POSSIBLY DUE IN PART TO THE COARSER BOUNDARY LAYER RESOLUTION...THINK THAT IF THE INVERSION DOES SET UP AS STRONG AS BOTH MODELS SUGGEST...EVEN IF THE WINDS ARE A BIT STRONGER THEY MAY SIMPLY FLOW OVER THE INVERSION WITH LITTLE AIR MOVEMENT AT THE SURFACE BELOW IT. THUS...FEEL IT IS A GOOD IDEA TO MENTION THE POSSIBILITY OF FOG IN THE GRIDS AT THIS POINT...EVEN THOUGH EXACT TIMING IS STILL RELATIVELY UNCLEAR. ANY FOG THAT WOULD FORM WOULD GREATLY INFLUENCE TEMPERATURES...AS WELL AS HELP MAINTAIN THE INVERSION...SO LOWERED HIGHS A BIT IN THE EAST TO ACCOUNT FOR THIS POSSIBILITY. ACROSS THE EAST ON SATURDAY...TEMPERATURES SHOULD BE ABLE TO RISE INTO THE 30S AND POSSIBLY 40S IN AREAS AS INCREASED MIXING LEADS TO STRONGER SURFACE WINDS...PREVENTING FOG POTENTIAL AND TAPPING INTO WARMER AIR ABOVE THE SURFACE. .LONG TERM...SUNDAY THROUGH WEDNESDAY MAIN CHALLENGE IN THE EXTENDED CONTINUES TO BE THE INCONSISTENCY BETWEEN MODEL SOLUTIONS. THE UPPER LEVEL PATTERN WILL START OFF FEATURING A BROAD TROUGH OVER THE WESTERN HALF OF THE COUNTRY...AND A RIDGE OVER THE EAST. THE GFS SLIDES THE TROUGH TO THE ROCKIES BY TUESDAY MORNING...THEN HAS IT MERGING WITH ANOTHER TROUGH TO THE NORTHWEST TUESDAY NIGHT AND BECOMING SITUATED OVER THE PLAINS ON WEDNESDAY. THE ECMWF IS MUCH FASTER...PUSHING THE TROUGH TO THE PLAINS BY TUESDAY MORNING...THEN QUICKLY EASTWARD AND NEVER MERGING WITH THE NEXT TROUGH...THOUGH THAT TROUGH DOES MOVE OVER THE PLAINS WEDNESDAY. AT THE SURFACE...GOOD AGREEMENT AMONGST THE MODELS OF A TROUGH OVER THE PLAINS EARLY SUNDAY AND WEAK HIGH PRESSURE BUILDING OVER THE AREA SUNDAY EVENING...AND THAT IS WHERE ANY REASONABLE AGREEMENT ENDS. THE GFS SHOWS A LOW PRESSURE SYSTEM TRACKING FROM EASTERN COLORADO SUNDAY EVENING TO WISCONSIN BY MONDAY EVENING...WITH PRECIPITATION OVER THE CWA MUCH OF MONDAY. THE ECMWF HAS A MUCH WEAKER FASTER MOVING LOW WITH LITTLE IN THE WAY OF PRECIPITATION. THE DIFFERENCES IN TIMING CONTINUES THROUGH THE END OF THE PERIOD AS THE ECMWF TRACKS HIGH PRESSURE ACROSS THE AREA ON WEDNESDAY AND THE GFS IS ABOUT 12 HOURS BEHIND. CURRENT MODEL DISCREPANCIES APPEAR TO GET EVEN WORSE PAST THE END OF THE LONG TERM PERIOD. SO...BASICALLY CHANGED VERY LITTLE IN THE EXTENDED WITH THE EXCEPTION OF PRECIPITATION SUNDAY NIGHT AND MONDAY. AFTER PERUSING THROUGH GFS FORECAST SOUNDINGS...IT APPEARS THERE WILL BE A FAIRLY DECENT LAYER OF WARM AIR ALOFT THAT COULD RESULT IN PRECIPITATION BEGINNING AS FREEZING RAIN SUNDAY NIGHT...AND HAVE SPREAD THAT CHANCE FURTHER WEST THAN THE PREVIOUS FORECAST INDICATED. SOUNDINGS ALSO INDICATING THE COOLER AIR TAKING OVER SOONER ON MONDAY...SO WENT WITH ALL SNOW IN THE NORTH AND A POSSIBLE MIX OF RAIN OR SNOW ACROSS THE SOUTH. BY MONDAY NIGHT...ANY CONTINUING PRECIPITATION SHOULD BE ALL SNOW. DRY CONDITIONS EXPECTED TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES IN BEHIND THE EXITING LOW. TEMPERATURES WILL STILL BE FAIRLY MILD ON SUNDAY AS WEAK WAA CONTINUES AND H85 TEMPS REMAIN JUST ABOVE ZERO. THE COOLER AIR BEGINS TO GET PULLED INTO THE REGION EARLY MONDAY...WITH H85 TEMPS IN THE SINGLE DIGITS BELOW ZERO FROM MONDAY EVENING ONWARD. WENT WITH A SLIGHT COOLING TREND MONDAY THROUGH WEDNESDAY...THOUGH TEMPS LOOK TO BE NEAR OF JUST ABOVE NORMAL. && .AVIATION... GUSTY SOUTH WINDS OF 20 TO 30 MPH WILL CONTINUE EARLY THIS MORNING FROM THE JAMES RIVER VALLEY EASTWARD...MAINLY AFFECTING KABR...KATY AND K8D3. VSBYS MAY FALL TO AROUND 2SM AT TIMES DUE TO BLOWING SNOW...MAINLY ALONG AND EAST OF INTERSTATE 29. THE STRONG WINDS...AND THE POTENTIAL FOR BLOWING SNOW... WILL SUBSIDE AFTER 12Z. VFR CONDITIONS WILL THEN PREVAIL ACROSS THE ENTIRE CWA WITH SCT- BKN HIGH CLOUDS AOA 20K FEET STREAMING ACROSS THE REGION. VSBYS WILL BE UNRESTRICTED. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...PARKIN SHORT TERM...ECKSTEIN LONG TERM...PARKIN AVIATION...PARKIN WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 256 PM MST THU JAN 3 2008 .SHORT TERM... (TONIGHT AND FRIDAY) CURRENTLY...SW FLOW ALOFT WAS EVIDENT AS PER IR SATELLITE IMAGERY AND RUC H5 ANALYSIS THU AFTN. SW WINDS AT THE SFC ACROSS THE CWA...THOUGH NOT STRONG...REMAINED BRISK AT TIMES AND REALLY HELPED TO MIX AND WARM THE LOWER LEVELS. EVEN WITH THE THICK MID AND HIGH CLOUD LAYER OVER MUCH OF THE CWA...E PLAINS SITE THAT EXPERIENCED BRISK W WINDS THIS AFTN WARMED INTO THE MID 50S TO LOWER 60S. OTHER SITES...SUCH AS KTAD OR KLAA...REPORTED CALM TO LIGHT EASTERLY WINDS...AND TEMPS THERE REMAINED IN THE UPPER 40S TO 50 F. TONIGHT AND TOMORROW...THE UPPER LOW OVER THE PACIFIC APPROACHS THE PAC NW COAST THROUGH THE NEXT 24 HRS...STRENGTHENING THE SW FLOW ALOFT OVER THE 4 CORNERS. THIS SW FLOW IS FORECAST TO DRAW AN IMPRESSIVE AMOUNT OF MOISTURE RIGHT INTO THE CONTDVD...ESPECIALLY THE SAN JUANS...INTO THE WEEKEND. THIS PATTERN ESTABLISHES ITSELF THE NEXT 24 HOURS...AND CHANGES VERY LITTLE. BOTH GFS AND NAM MODELS INDICATE THAT THE ONSET OF PCPN MIGHT BE DELAYED SLIGHTLY...SO ADJUSTED THE POP GRIDS SO TO TRY AND ILLUSTRATE A SLOW AND GRADUAL INCREASE OF PCPN TONIGHT. PREVIOUS SHIFT HAD INCREASED POPS ALONG THE CONTDVD TO SCATTERED AFTER MIDNIGHT...AND SEE NO REASON TO ADJUST THIS AS IT CARRIES THROUGH TOMORROW. FEEL THAT THERE IS A SLIGHT CHANCE FOR SOME OF THE PCPN TO SPILL OVER TO THE SLV AND E MTS...AND EVEN THE SOUTHERN FOOTHILLS...BY FRI AFTN. THEREFORE...PAINTED SOME ISOLATED POPS THERE TO COVER THAT CHANCE...HOWEVER FEEL THAT MOST OF THE AVAILABLE MOISTURE WILL BE AFFECTING THE CONTDVD. FORECAST 1 TO 2 INCHES TONIGHT FOR THE W AREAS...THEN ANOTHER 2 TO 3 INCHES DURING THE DAY TOMORROW. REAL CHALLENGE IS GOING TO BE THE TEMPS. PLENTY OF MID AND HIGH LEVEL CLOUD COVER...COUPLED WITH BRISK W-SW WINDS...SHOULD KEEP MIN TEMPS TONIGHT FROM DROPPING TO LOW. SO...WENT WITH MINS IN THE TEENS TO LOWER 20S FOR THE PLAINS...AND EVEN KEPT KALS ON THE POSITIVE SIDE OF ZERO. AS FOR MAX TEMPS FRI...700 AND 850 MB TEMP CHARTS INDICATE A SLIGHT COOLING TOMORROW WHICH MIGHT BE A REFLECTION OF MORE CLOUD COVER AND LESS WIND EXPECTED. LATEST NUMERICAL GUIDANCE FORECAST TEMPS SLIGHTLY BELOW WHAT WERE REALIZED TODAY...WHICH SEEMS REASONABLE...SO WENT WITH A GFS/NAM BLEND. MOORE .LONG TERM... (FRIDAY NIGHT THROUGH THURSDAY) ...LONG DURATION MAJOR WINTER STORM EVENT FOR THE WESTERN UNITED STATES... NOT TOO MUCH CHANGE IN THINKING REGARDING WELL ADVERTISED WINTER STORM EVENT FOR THE WESTERN CONUS. SLOW MOVING LONG WAVE TROUGH WITH PLENTY OF MOISTURE...5 STANDARD DEVIATIONS ABOVE NORMAL ACCORDING TO NATL CENTERS...WILL BE COMING ONSHORE TOMORROW AND THE BRUNT OF IT SHOULD BE CROSSING OUR AREA DURING THE SUNDAY/MONDAY TIME FRAME. IN THE MEANTIME...I EXPECT SOME SNOW...ESPECIALLY OVER THE SW MTNS...FRIDAY NIGHT INTO SATURDAY. ATTM...I AM NOT OVERLY EXCITED ON SNOWFALL AMOUNTS AS THE LAPSE RATES ARE PAULTRY AT BEST...HOWEVER THERE IS PRETTY GOOD UPSLOPE WITH THE MODERATES SW 700 MB FLOW IMPINGING ON THE SW MTNS. THE SHOW SHOULD REALLY START TO PICK UP IN EARNEST BY SAT NITE AND INTO SUNDAY GOING INTO MONDAY. LAPSE RATES IMPROVE DRAMATICALLY AS WE GO INTO SAT NITE/SUNDAY AND THE 700 MB FLOW ONLY INCREASES MORE. THIS SHOULD BRING HEAVY SNOWS INTO THE SW MTNS DURING THE ABOVE MENTIONED TIME FRAME. QPF OFF THE GUIDANCE WAS PRETTY INCREDIBLE (1" IN 6 HRS) DURING SUNDAY. ALTHUGH THIS IS POSSIBLE...I DID CUT BACK QUITE A BIT FROM THESE VALUES. NO MATTER WHAT...WE WILL LIKELY SEE MANY FEET OF SNOW OVER THE SW MTNS BY LATE MONDAY. AS FOR THE C MTNS...THIS AREA WILL LIKELY SEE SNOW...BUT THE HEAVIEST MAY NOT GET INTO THIS REGION UNTIL THE 700 MB FLOW SHIFTS TO A MORE W AND THEN NW DIRECTION. THIS WILL LIKELY NOT OCCUR UNTIL LATE SUNDAY INTO MONDAY AS THE TROUGH GOES BY. FOR THE REST OF THE REGION BETWEEN LATE FRI INTO SUNDAY...WARM AND WINDY. HI TEMPS SAT WILL BE IN THE 50S AND 60S ON THE PLAINS. WITH ALL OF THE WIND...I EVEN EXPECT ALAMOSA...THE SAN LUIS VALLEY (SLV) TO FINALLY BREAK OUT OF THE INVERSION AND HAVE TEMPS IN THE 30S BOTH DAYS. WINDS WILL ALSO BE AN ISSUE THIS WEEKEND WITH THE WORST OF IT OVER AND E OF THE S MTNS ON SAT. EXPECT WINDS IN THE 25-35 MPH RANGE WITH GUSTS OVER 50 IN WIND PRONE LOCATIONS. MAY SEE SOME OF THESE WINDS GET OUT ONTO THE E PLAINS. WINDS WILL KEEP MINS UP AT NIGHT AND HAVE KEPT TEMPS UP IN THE "BANANA BELT" (AREAS IMMEDIATELY ADJACENT TO THE MTNS FACING THE PLAINS) REGION OF OUR FCST AREA. BY MONDAY...THE PAC FRONT MOVES ACROSS. THIS WILL LEAD TO A BRIEF PERIOD OF UPSLOP OVER THE E PLAINS...BUT I REALLY DO NOT EXPECT MUCH OF ANY PRECIP...AND HAVE KEPT POPS IN THE 10% RANGE FOR THE PLAINS. TEMPS WILL FALL INTO THE 40S. BEYOND THIS DATE...LONG RANGE GUIDANCE GOES INTO PRETTY BIG DISAGREEMENT. FOR NOW I BASE THE REST OF THE DISCUSSION ON THE EC MODEL AS GFS SEEMS TO BE HAVING RUN TO RUN CONTINUITY PROBLEMS. WE SHOULD SEE A BIT OF A REPRIEVE ON TUESDAY OVER MOST OF THE REGION AS WEAK RIDGING BUILDS OVER AREA. ONLY EXCEPTION TO THIS WILL BE THE C MTNS WHERE NW FLOW WILL KEEP THE FLAKES A FLYIN`. BY TUESDAY...ANOTHER WX SYSTEM IN THE NW FLOW MOVES INTO THE AREA. GIVEN THE FLOW (W TO NW) AND THE LAPSE RATES...THE C MTNS SHOULD SEE THE BRUNT OF THE SNOW WITH THIS SYTEM. THIS SYSTEM...AS HAVE MANY OTHERS THIS WINTER SEASON...WILL BE PROGRESSIVE SO THE CHANCES OF PRECIP ON THE PLAINS SHOULD BE LOW. ANOTHER WEAK RIDGE MOVES ACROSS THE REGION LATER WED AND THU...AND THEN ANOTHER SYSTEM IS FCST TO AFFECT THE AREA LATER FRIDAY AND INTO THE WEEKEND. THIS SYSTEM IS FCST TO BE A BIT STRONGER AND SLOWER ON THE NEW 12Z EC...BUT I WILL BELIEVE IT WHEN I SEE IT. /HODANISH && .AVIATION... VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR TAF SITES THE NEXT 24 HRS...THOUGH THERE WILL BE A GENERAL LOWERING OF MID AND HIGH LEVEL CLOUDS. FLOW ALOFT WILL BE OUT OF THE W TO SW...AND ISOLATED SNOW WILL BE ENCROACHING UPON KALS BY MIDDAY TOMORROW. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 27/34 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 425 PM EST THU JAN 3 2008 .SYNOPSIS... IR IMAGERY AND RUC ANALYSIS SHOW AN UPPER LEVEL TROUGH PUSHING OFF THE EAST COAST INTO THE ATLANTIC OCEAN...WITH NEARLY ZONAL FLOW ACROSS THE CENTRAL UNITED STATES. ANOTHER TROUGH IS CLOSE TO MOVING ONSHORE FROM THE PACIFIC OCEAN. AT THE SURFACE...HIGH PRESSURE DOMINATES MUCH OF THE EASTERN UNITED STATES...WITH LOW PRESSURE PUSHING EAST OVER HUDSON BAY. THE TIGHT PRESSURE GRADIENT BROUGHT INCREASED WINDS TO THE AREA...ALTHOUGH WIND SPEEDS DID NOT GET QUITE AS HIGH AS EXPECTED. MARINE PLATFORMS AND COASTAL LOCATIONS REPORTED HIGHER WIND SPEEDS...WITH 36 KT GUST AT KIWD...53 KT GUSTS AT ROCK OF AGES...AND 47 KNOTS AT PASSAGE ISLAND. WIND SPEEDS HAVE PICKED UP ALONG THE LAKE MICHIGAN SHORELINE OVER THE LAST 3 HOURS...WITH MULTIPLE LOCATIONS REPORTING 30 TO 35 KNOT GUSTS. && .SHORT TERM (TONIGHT AND FRI)... QUIET WEATHER PATTERN OVER THE NEXT 24 HOURS. WINDS SHOULD DECREASE THROUGH THE EVENING HOURS AS THE LOW LEVEL JET PUSHES EAST OF THE AREA. WENT WITH LOWER MOS GUIDANCE TONIGHT AS TEMPS DROPPED OFF QUITE A BIT LAST NIGHT...ALTHOUGH WINDS SHOULD REMAIN IN THE 5 TO 10 MPH RANGE OVERNIGHT. DID NOT PUT ANY FOG IN THE FORECAST BECAUSE THE WINDS SHOULD CONTINUE THROUGH THE NIGHT...OTHERWISE MIGHT HAVE EXPECTED FOG TO DEVELOP OVER LOCATIONS WITH THE FRESHEST SNOW COVER. SOME LOW LEVEL MOISTURE SHOULD REMAIN OVER THE AREA TOMORROW... ALTHOUGH LITTLE VERTICAL MOTION SHOULD PREVENT ANY PRECIPITATION FROM OCCURRING. SW WINDS WILL CONTINUE TO BRING WARMER TEMPERATURES...NEAR 30 DEGREES ACROSS UPPER MICHIGAN. .LONG TERM (FRI NIGHT THRU THU)... MAIN FCST ISSUE IS WHEN WILL STRATUS AND POSSIBLE FOG SETTLE OVER THE AREA AS PERSISTENT S TO SW FLOW WAA CONTINUES. GFS/NAM ARE IN GOOD AGREEMENT SHOWING ONLY SHALLOW MOISTURE OVER THE AREA FRI NIGHT THRU SUN MORNING...AND WITH LITTLE IN THE WAY OF FORCING DUE TO UPPER JET WELL W OF HERE EXTENDING FROM THE SW CONUS TO THE NRN PLAINS...MEASURABLE PCPN SEEMS UNLIKELY. THE NAM/GFS HOWEVER APPEAR MUCH TOO QUICK WITH THE LOW LEVEL MOISTENING THEY INDICATE FOR TONIGHT AND FRI HERE. SFC DWPTS ALL THE WAY DOWN TO THE SRN PLAINS ARE NO HIGHER THAN 15 TO 20F THIS AFTN. MELTING SNOW COVER ACROSS CNTRL PLAINS WILL BEGIN TO LEAD TO INCREASING SFC DWPTS WITH TIME...AND FLOW OFF THE GULF OF MEXICO WHICH IS NOW DEVELOPING INTO TX WILL LEAD TO A STRONG INCREASE OF LOW-LEVEL MOISTURE NWD. THIS MOISTURE OVERRIDING/LIFTING OVER THE NEAR SFC COOL AIR/SNOW COVER WILL RESULT IN A RAPID DEVELOPMENT OF STRATUS. BASED ON THE NAM/GFS...IT PROBABLY WON`T BE UNTIL FRI NIGHT THAT A GOOD PUSH OF HIGHER DWPTS AT LEAST INTO THE 30S SURGES N INTO THE CNTRL PLAINS TOWARD THE UPPER MISSISSIPPI VALLEY. SO THAT IS THE TIME THAT RAPID STRATUS DEVELOPMENT SHOULD GET UNDERWAY. WOULD EXPECT STRATUS TO REACH THE FCST AREA LATE FRI NIGHT BUT PROBABLY MORE LIKELY SAT MORNING. ONCE THE STRATUS ARRIVES IT SHOULD PERSIST THRU AT LEAST SUN ALONG WITH SOME FOG AS SFC DWPTS CONTINUE TO RISE. LOW-LEVEL MOIST ISENTROPIC ASCENT AS VIEWED ON THE 280K SFC MAY BE SUFFICIENT FOR -DZ SAT NIGHT/SUN. REMOVED ANY MENTION OF -RA AS DEEP MOISTURE IS LACKING. MAX/MIN TEMPS WILL BE HIGHER EACH DAY AS AIRMASS CONTINUES TO WARM. MIN TEMPS WILL BE MOST AFFECTED AS INCREASINGLY MOIST LOW-LEVEL AIRMASS AND STRATUS STRONGLY LIMIT TEMP FALLS AT NIGHT. TEMPS SHOULD NOT FALL BACK BLO FREEZING SAT NIGHT AND SUN NIGHT. MON THRU THU...CONFIDENCE DURING THIS TIME FRAME IS VERY LOW AS THERE HAS BEEN POOR RUN-TO-RUN CONTINUITY ON PROGRESSION/STRENGTH OF SHORTWAVES MOVING EWD FROM THE MEAN W COAST TROF WHICH WILL BE DRIFTING TOWARD THE CNTRL CONUS BY THE END OF THE PERIOD. IN PAST DAYS...THERE WAS A SIGNAL FOR A STRONG LOW PRES SYSTEM LIFTING NE AND PASSING W OF UPPER MI...PROVIDING FOR UNSEASONABLE WARMTH AND POSSIBLE SIGNIFICANT RAIN HERE. OVERALL MODEL TREND RECENTLY HAS BEEN TO DOWNPLAY SIGNIFICANT SFC DEVELOPMENT SOMEWHAT. HOWEVER... BEING SEVERAL DAYS OUT INTO THE MODEL RUNS...A STRONG SYSTEM CANNOT BE DISCOUNTED SINCE THERE HAVE BEEN SO MANY MODEL RUNS THAT HAVE SHOWED IT IN THE LAST SEVERAL DAYS (INCLUDING 12Z GFS/ECMWF FOR TUE). FOR THE TIME BEING...THIS FCST ISSUANCE WILL LEAN TOWARD HPC GUIDANCE FOR POSITION OF FRONTS/SFC WAVES...BUT IT WILL STILL RETAIN MUCH OF THE PREVIOUS FCST IDEAS WHICH IS ALWAYS DESIREABLE WHEN THERE IS CONSIDERABLE MODEL UNCERTAINTY. AFTER UNSEASONABLE WARMTH LATE IN THE WEEKEND...TEMPS SHOULD GRADUALLY TREND DOWNWARD DURING THIS PERIOD...BUT OBVIOUSLY ANY SIGNIFICANT SFC LOW PRES DEVELOPMENT COULD DRASTICALLY ALTER THAT PLAN. EVEN WITH A GRADUAL COOLING TREND...TEMPS WILL REMAIN WELL ABOVE NORMAL FOR THIS PERIOD. AS FOR PCPN...PLAN TO CARRY AT LEAST LOW CHC POPS THRU THE ENTIRE FCST PERIOD GIVEN UNCERTAINTY IN WHERE SLOWLY EWD MOVING FRONTAL BOUNDARY/SFC WAVES WILL BE LOCATED AS MEAN TROF DRIFTS TOWARD THE CNTRL CONUS. THERE COULD BE ONE OR MORE PERIODS OF SIGNIFICANT PCPN DEPENDING ON PROGRESSION OF SHORTWAVES. OVER THE LAST SEVERAL DAYS OF MODEL RUNS...IT WOULD APPEAR MON NIGHT/TUE MAY HAVE THE BEST OPPORTUNITY FOR PCPN. WILL TRANSITION PTYPE TO RAIN/SNOW TUE NIGHT AND TO ONLY SNOW FOR WED/THU. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... STRONG SOUTHWEST WINDS WITH 40 KT GUSTS SHOULD CONTINUE THROUGH THE DAY...WITH REDUCTION IN VISIBILITIES DUE TO BLOWING SNOW. FOR THE MOST PART...VIS SHOULD REMAIN ABOVE 5SM IN THE BLSN. NEXT SHOT AT LOWER CLOUDS WILL ARRIVE LATE TONIGHT AS MOISTURE INCREASES BELOW 5KFT. DEVELOPMENT OF STRATUS DECK WITH INCOMING MOISTURE AND WINDS REMAINING AROUND 10 KT SHOULD PREVENT A RADIATION FOG EVENT OVER THE FRESH SNOWPACK. CIG AT KCMX WILL LIKELY BE A TOUCH LOWER THAN KSAW DUE TO ADDITIONAL MOISTURE CONTRIBUTION FROM MARINE LAYER AND GREATER RECENT SNOWFALL. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS WILL BEGIN TO DIMINISH THIS EVENING AS THE PRESSURE GRADIENT RELAXES BETWEEN HIGH PRESSURE OVER THE SOUTHEAST AND LOW PRESSURE OVER HUDSON BAY. WINDS WILL PICK UP A BIT OUT OF THE SOUTH LATE SATURDAY AND SUNDAY...WITH WINDS UP TO 30 KT ON THE EASTERN HALF OF THE LAKE. AFTER SUNDAY NIGHT...WINDS SHOULD REMAIN BELOW 25 KNOTS THROUGH TUESDAY. HOWEVER...WILL NEED TO KEEP AN EYE ON A LOW PRES SYSTEM THAT MAY TRACK INTO THE UPPER LAKES TUE. IF SYSTEM DEVELOPS...WINDS COULD BE QUITE A BIT HIGHER THAN REFLECTED IN THIS FCST ISSUANCE. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN... WIND ADVY UNTIL 7 PM EST THIS EVENING MIZ005>007-013-014-085. LAKE SUPERIOR... GALE WARNING UNTIL 5 PM EST THIS EVENING FOR LSZ240>243-248. GALE WARNING UNTIL 7 PM EST THIS EVENING LSZ244-245-249>251-265. GALE WARNING UNTIL 9 PM EST THIS EVENING LSZ263-264-266-267. LAKE MICHIGAN... GALE WARNING UNTIL 1 AM EST FRIDAY LMZ221-248-250. && $$ SHORT TERM...TAG LONG TERM...ROLFSON AVIATION...TAG MARINE...TAG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 335 PM EST THU JAN 3 2008 .DISCUSSION...LATEST SURFACE/RUC ANALYSIS THIS AFTERNOON REVEALING MID LEVEL RIDGING NOW PUSHING INTO THE EASTERN GREAT LAKES. WINDS ON THE BACK SIDE OF THIS RIDGE HAVE INCREASED DRAMATICALLY OVER THE PAST FEW HOURS WITH GUSTS TO 30 KNOTS BECOMING MORE COMMON. CLOUDY SKIES HAVE ALSO CONTINUED THROUGH THE AFTERNOON HOURS. FORECAST CONCERNS FOR TONIGHT REVOLVE AROUND WINDS AND CLOUD COVER. TONIGHT...GUSTY WINDS WILL CONTINUE ACROSS NORTHERN LOWER MICHIGAN. THE STRONGEST WINDS ARE EXPECTED TO BE ALONG THE LAKE MICHIGAN SHORELINE THIS EVENING WITH WINDS IN THE MIXED LAYER OVER THE LAKE AROUND 40 KNOTS. ALTHOUGH IT WILL BE GUSTY EVERYWHERE TONIGHT...IT DOES NOT APPEAR WE WILL REACH WIND ADVISORY THRESHOLDS INLAND AWAY FROM THE LAKE. THUS...WIND ADVISORIES WILL ONLY REMAIN FOR AREAS ALONG THE LAKE MICHIGAN SHORELINE. AS FOR CLOUD COVER...MODELS ARE CONSISTENT ON KEEPING A 2-3KFT INVERSION AROUND THROUGH THE NIGHT...TRAPPING THE MOISTURE OVER NORTHERN MICHIGAN. THUS...MOSTLY CLOUDY SKIES WILL BE COMMON...AND WITH THE WINDS...WILL KEEP TEMPERATURES FAIRLY STEADY IN THE UPPER TEENS TO LOWER 20S TONIGHT. TOMORROW...WILL BE A QUIETER DAY. GUSTY SOUTHWEST WINDS WILL CONTINUE...BUT WILL BE MUCH WEAKER. CLOUD COVER WILL PERSIST IN THE MORNING...THEN GIVE WAY TO SOME PARTIAL SUNSHINE BY MID AFTERNOON. WITH THE HELP OF LATE DAY WARM AIR ADVECTION... TEMPERATURES WILL RISE TO AROUND 30 DEGREES IN THE AFTERNOON. KAS LATER PERIODS...BIG WARM-UP COMING. DEEP SW FLOW WILL CONTINUE FROM NOW UNTIL THE MID PART OF NEXT WEEK. TEMPS ARE THE MAIN CONCERN FOR THE WEEKEND...ALONG WITH ASSOCIATED CHANCES OF FOG/DRIZZLE/STRATUS. MODELS...NO BIG ISSUES NOTED. BOTH HANDLE THE ONE WEAKNESS THAT MOVES THRU THE UPPER RIDGE LATE SATURDAY SIMILARLY. FRIDAY NIGHT...CIRRUS SHIELD SHOULD GRADUALLY THIN OUT AS SHORTWAVE RIDGE AXIS SLIDES IN. BUT...STILL AN ABUNDANT AMOUNT OF MOISTURE TRAPPED BENEATH 900MB. THIS MOISTURE WILL BE ASSISTED BY SNOWMELT FROM SATURDAY. DOWNWIND OF LAKE MI...AND OVER THE HIGHER TERRAIN AREAS...LOW CLOUDS WILL MAINTAIN THEMSELVES AT LEAST...AND LIKELY REFORM IF THERE IS ANY MIXING OUT ON SATURDAY. NE LOWER MI...WITH DOWNSLOPING SW LOW LEVEL WINDS...WILL SEE LESS STRATUS/STRATOCU. MIN TEMPS WILL BE ABOVE GUIDANCE AND VERY EARLY ON...WITH RISING TEMPS OVERNIGHT. SATURDAY...LOW LEVELS CONTINUE TO MOISTEN IN S TO SW FLOW BELOW 850MB. MOIST LAYER RISES UP TO 875MB/4K FEET. THIS WILL MAKE LOW CLOUD COVER PREVALENT ACROSS THE FORECAST AREA...AND INTRODUCE A DRIZZLE THREAT. SOME FREEZING DRIZZLE COULD OCCUR IN THE MORNING BEFORE TEMPS EMPHATICALLY WARM ABOVE FREEZING. WITH THE WARMER TEMPS AND ADDITIONAL SNOWMELT MOISTURE...SOME FOG WILL DEVELOP... ESPECIALLY IN THE PM AS SURFACE DEW POINTS POKE UP TO AROUND FREEZING. MAX TEMPS WILL RANGE FROM THE MID 30S TO AROUND 40. SAT NIGHT/SUNDAY...MORE OF THE SAME. ABUNDANT LOW LEVEL MOISTURE... ENHANCED BY SNOWMELT HERE AND UPSTREAM...WILL MAINTAIN STRATUS/ FOG/DRIZZLE THRU THESE PERIODS. NAM/GFS DO NOT HAVE ANY SORT OF MID/UPPER LEVEL MOISTURE PRESENT...THANKS TO THE STRONG RIDGING ALOFT. SO DON/T SEE ANY REAL CHANCE OF MEASURABLE PRECIP. WILL GO ABOVE GUIDANCE MIN TEMPS...AND NEAR OR SLIGHTLY BELOW GUIDANCE MAX TEMPS. REST OF THE FORECAST...DEEP SW FLOW WILL PROVIDE UNSEASONABLY WARM WX EARLY ON. POPS WILL FINALLY INCREASE INTO EARLY NEXT WEEK AS A COLD FRONT APPROACHES FROM THE WEST. AS HPC NOTES...THE MODELS HAVE ACTUALLY DIVERGED ON TIMING THIS FRONT THRU THE REGION. THE CURRENT HPC FORECAST FOLLOWS A LARGER CLUSTER OF MODELS (ECMWF AND NA ENSEMBLE MEANS) THAT MAINTAINS CONTINUITY FROM EARLIER PROGS. THAT SEEMS A GOOD WAY TO GO. WITH THAT IN MIND...THE COLD FRONT WILL LIKELY HANG UP OVER OUR HEADS WHILE A COUPLE OF WAVES MOVE UP ALONG IT FROM MONDAY INTO EARLY WED. WILL KICK POPS UP TO LIKELY (ALL RAIN) MONDAY THRU TUESDAY. AS THE FRONT GOES THRU TUESDAY NIGHT/WED...RAIN WILL MIX WITH AND TURN TO SNOW. AIRMASS BEHIND THE FRONT WILL OBVIOUSLY BE COOLER...BUT OF PACIFIC ORIGIN AND STILL WARMER THAN NORMAL. ANOTHER SYSTEM PASSING JUST TO OUR SOUTH WILL MAINTAIN A CHANCE OF SYNOPTIC SNOW INTO THURSDAY. ZOLTOWSKI && .AVIATION... /ISSUED 1232 PM EST THU JAN 3 2008/ MVFR/LOW END VFR STRATO CU DECK SHOULD BEGIN TO SCOUR OUT SOME LATER THIS AFTERNOON AS DRY AIR AND WARMING MID LEVELS HELP TAME THE OVER- WATER INSTABILITY. BIGGER STORY TODAY THROUGH THIS EVENING WILL BE STRONG SOUTHWEST WINDS...GUSTING UPWARDS OF 30 KNOTS...AS PRESSURE GRADIENT TIGHTENS OVER THE NORTHERN LAKES. WHILE WINDS BEGIN TO SUBSIDE OVERNIGHT...MODEL CROSS SECTION MOISTURE PROGS INDICATE THE RETURN OF MVFR OVERCAST...WHICH SHOULD CONTINUE THROUGH TOMORROW MORNING. MSB && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ015-016-019-020-025. LM...GALE WARNING UNTIL 10 AM EST FRIDAY FOR LMZ323-341-342-344>346. LH...GALE WARNING UNTIL 10 AM EST FRIDAY FOR LHZ345>349. LS...GALE WARNING UNTIL 10 AM EST FRIDAY FOR LSZ321-322. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1232 PM EST THU JAN 3 2008 .AVIATION...MVFR/LOW END VFR STRATO CU DECK SHOULD BEGIN TO SCOUR OUT SOME LATER THIS AFTERNOON AS DRY AIR AND WARMING MID LEVELS HELP TAME THE OVER-WATER INSTABILITY. BIGGER STORY TODAY THROUGH THIS EVENING WILL BE STRONG SOUTHWEST WINDS...GUSTING UPWARDS OF 30 KNOTS...AS PRESSURE GRADIENT TIGHTENS OVER THE NORTHERN LAKES. WHILE WINDS BEGIN TO SUBSIDE OVERNIGHT...MODEL CROSS SECTION MOISTURE PROGS INDICATE THE RETURN OF MVFR OVERCAST...WHICH SHOULD CONTINUE THROUGH TOMORROW MORNING. MSB && .UPDATE...ISSUED 1020 AM LATEST RUC ANALYSIS THIS MORNING REVEALS THE MID LEVEL RIDGE AXIS CENTERED ALMOST DIRECTLY OVER THE NORTH-SOUTH AXIS OF THE EASTERN SHORE OF LAKE MICHIGAN. LIGHT AND VARIABLE WINDS ARE STARTING TO TURN SOUTHERLY NEAR THE LAKE MICHIGAN SHORELINE WITH THE ARRIVAL OF THIS AXIS. THE SCATTERED SNOW SHOWER ACTIVITY FROM OVERNIGHT HAS DWINDLED TO NOTHING MORE THAN FLURRIES...AFFECTING AREAS ALONG THE LAKE MICHIGAN SHORELINE...INTO AREAS AROUND THE STRAITS. A SECONDARY AREA OF FLURRIES OR VERY LIGHT SNOW SHOWERS IS MOVING NORTHEAST ACROSS IN THE VICINITY OF GRAND RAPIDS. HOWEVER...LAST FEW RADAR SCANS HAS SHOWN A WEAKENING TREND. THIS SHOULD CONTINUE TO BE THE CASE AS IT LOSES ANY HELP FROM UPSLOPE FLOW. THE NAM AND GFS KEEP ENOUGH SHALLOW INSTABILITY AROUND INTO THE EARLY AFTERNOON HOURS TO KEEP INVERSION HEIGHTS AROUND 3KFT AROUND LAKE MICHIGAN. THUS...SOME SCATTERED FLURRIES CANNOT BE RULED OUT INTO THE EARLY AFTERNOON HOURS FOR LOCATIONS ALONG THE SHORELINE...STRETCHING NORTHWARD INTO EASTERN UPPER MICHIGAN. FINALLY...BY MID TO LATE AFTERNOON...ANTICYCLONIC FLOW WILL TAKE OVER...AND WE SHOULD JUST BE LEFT WITH SOME VERY SHALLOW LAKE CLOUDS NEAR THE LAKE MICHIGAN SHORELINE. IN THE MEANTIME...MID LEVEL CLOUDS ON THE BACK SIDE OF THE RIDGE AXIS ARE ALREADY INVADING NORTHERN MICHIGAN THIS MORNING AND WILL OVERTAKE THE AREA BY MIDDAY. THUS...WILL BUMP UP SKY COVER A BIT TO REFLECT MOSTLY CLOUDY SKIES FOR THE REMAINDER OF THE DAY AS VERY LITTLE SUN WILL BE SEEN. IN ASSOCIATION WITH INCREASING CLOUD COVER...HIGH TEMPERATURES WILL ALSO BE BUMPED DOWN A FEW DEGREES IN MOST PLACES. WE SHOULD STILL SEE TEMPERATURES CLIMB INTO THE LOWER TO MIDDLE 20S...WITH PERHAPS SOME UPPER 20S NEAR THE LAKE MICHIGAN SHORELINE. OVERALL...FAIRLY CLOSE TO SEASONAL HIGH TEMPERATURES FOR EARLY JANUARY. NOW TAKING A LOOK AT WINDS. THE MIXED LAYER OFF THE 12Z MODELS THIS MORNING STILL CONTAIN 40 TO 45 KNOT WINDS. WINDS DROP OFF AS YOU HEAD FURTHER SOUTH...SO WILL KEEP THE ADVISORY AS IT APPEARS. GALES STILL LOOK GOOD AS WELL...SO NO CHANGES PLANNED FOR ANY OF THE HEADLINES. WILL MAKE A MENTION OF PATCHY BLOWING SNOW IN THE AREAS WHICH SAW 1 TO 3 INCHES OF VERY LIGHT FLUFFY SNOW LAST NIGHT...WHICH INCLUDES NORTHWEST LOWER MICHIGAN...MAINLY NORTH OF M-72...AND ACROSS EASTERN UPPER MICHIGAN. THE NATURE OF THE SNOW WILL ALLOW IT TO BLOW AROUND THIS AFTERNOON. KAS && .PREV DISCUSSION... /ISSUED 422 AM EST THU JAN 3 2008/ DISCUSSION...1000-850 MB WIND RIDGE AXIS IS NOW THROUGH MOST OF N LOWER IS BEGINNING TO MAKE ITS PRESENCE KNOWN WITH THE SNOW BANDS. WHILE MAINTAINING SOME NW FLOW CHARACTERISTICS, THE SNOW BANDS ARE BEGINNING TO MOVE TO THE NE PER THE APX 88D RADAR. MOST OF THE SNOW IS VERY LIGHT ATTM AS WELL. THE MAIN SFC RIDGE IS TO THE EAST OF THE REGION, AND 500 MB IS STILL TO THE WEST. HOWEVER, THE NEXT 850 MB TROUGH NORTH OF LAKE WINNIPEG, HAS A LLJ MAX OF 65 KNOTS THE TAIL OF WHICH IS AROUND 50 KNOTS AND IS HEADED TOWARD N MICHIGAN. THIS WILL BE THE MAIN CONCERN OF THE FORECAST PACKAGE. TODAY/TONIGHT/FRIDAY...FIRST THE FLURRIES WILL COME TO AN END AS THE DRY AIR IN THE 850-700 MB LAYER CONTINUES TO PLUMMET TO LESS THAN 30% AND THE WINDS TURN SW BY 15Z. THEN AROUND 18Z THE 850 MB JET CORE WILL BEGIN TO TRANSIT THE REGION. THE GFS SHOW 45KT AT 00Z WHILE THE NAM IS AROUND 50KT. HAVE GONE WITH THE SREF AT THE SFC WHICH IS SLIGHTLY LESS THAN 1/2 OF THE 850 MB WINDS AND GUSTS TO AROUND 45 MPH. THIS LOOKS TO BEGIN TO WIND DOWN AROUND 06Z, AS BOTH MODELS SLOW THE WIND DOWN TO THE 30 KNOT RANGE BY 12Z. THE GALES ON THE LAKES LOOK LIKE THEY WILL PROBABLY BE END AROUND 12Z, BUT WILL LEAVE THE 15Z END TIME ON FRIDAY FOR SOME ERROR. OTHERWISE AS THE WINDS WIND DOWN THE SW WIND WILL WARM THE REGION AND THE TEMPERATURES WILL BE IN THE LOWER 30S. SO MINIMAL MELTING LOOKS TO TAKE PLACE. FRIDAY NIGHT...TEMPERATURES FALL OFF TO THE MID 20S OVERNIGHT. THE SOUNDINGS ARE SATURATED FROM THE SFC TO 900 MB, HOWEVER, THE MOISTURE DOESN`T INCREASE WITH HEIGHT. THERE MAY BE A BIT OF FOG, BUT THIS DOESN`T LOOK LIKELY UNTIL... SATURDAY...TEMPERATURES START OUT IN THE 20S, BUT RAPIDLY WARM TO ABOVE FREEZING BY 18Z, THE SW FLOW CONTINUES TO NOT ONLY WARM, BUT MOISTURE LOWER LEVELS AS THE SOUNDINGS BEGIN TO SHOW A PROFILE WHERE THE MOISTURE INCREASE WITH HEIGHT. WITH ALL OF THE DRY AIR AT 850 MB AND UP, IT LOOKS LIKE THAT DRIZZLE BECOMES MORE AND MORE PREVALENT, AND I THINK THAT THE MOISTURE IN THE LOWER LEVELS ARE BEING UNDERPLAYED AS THE SNOW BEGINS TO MELT. SATURDAY NIGHT/SUNDAY...I BECOME MORE CONVINCED THAT DRIZZLE WILL BE THE MAIN HYDROMETEOR, AS THE DRY AIR ALOFT IN THE SOUNDINGS IS IMPRESSIVE, BUT THE MOISTURE IN THE LOWER LEVELS CONTINUE TO SHOW MOISTURE INCREASING WITH HEIGHT AND THERE IS WIND SHEAR (DIRECTIONAL AND SPEED) AS WELL TO HELP THE COLLISION PROCESS. MONDAY AND BEYOND...IT WILL BE INTERESTING TO SEE HOW MUCH SNOW IS LEFT AROUND HERE BY TUESDAY AS THE TEMPERATURES WARM TO THE MID 40S. HOWEVER, RAIN LOOKS MORE LIKELY NOW BY THE END OF MONDAY AS THE SOUNDINGS BECOME SATURATED. BY THE END OF TUESDAY, THE FRONT LOOKS LIKE IT IS THROUGH AND THE PROFILES COOL AND DRY. THIS SETS THE STAGE FOR WHETHER THERE WILL BE SNOW ON WEDNESDAY OR THURSDAY OF NEXT WEEK. DAY 6 MAY NEED SOME ADJUSTMENT IF THE GFS IS RIGHT AND DAY 7 (THURSDAY) MAY HAVE THE SNOW. LUTZ && .APX WATCHES/WARNINGS/ADVISORIES... MI...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 1 AM EST FRIDAY FOR MIZ008-015>025. LM...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST FRIDAY FOR LMZ323-341-342-344>346. LH...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST FRIDAY FOR LHZ345>349. LS...GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST FRIDAY FOR LSZ321-322. && $$ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1215 PM EST THU JAN 3 2008 UPDATED AVIATION SECTION FOR 18Z TAFS .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER NAMERICA WITH A RIDGE OVER MUCH OF THE PLAINS AND ROCKIES AND A TROF OVER THE EAST COAST. A STRONG SHORTWAVE WAS RIDING OVER THE WRN CONUS RIDGE THROUGH CENTRAL CANADA WITH 00Z RAOBS INDICATING 12 HR 5H PRES FALLS IN EXCESS OF 180M AHEAD OF THIS FEATURE. A STRONG WAA PATTERN HAS DEVELOPED AHEAD OF THIS SHORTWAVE PRODUCING A LARGE AREA OF MID-HIGH CLOUDS ACROSS CNTRL CANADA INTO THE NRN PLAINS. AT THE SFC...A HIGH PRES RIDGE EXTENDS FROM WESTERN GREAT LAKES SOUTH THROUGH THE CENTRAL AND SOUTHERN PLAINS WHILE A DEEP 992 MB SFC LOW IS APPROACHING HUDSON BAY. THE RESULTING STRONG SRLY GRAIDENT HAS PRODUCED SOUTHERLY WIND GUSTS IN EXCESS OF 30KT OVER A LARGE AREA EARLY THIS MORNING...FROM SRN MANITOBA AND NRN ONTARIO INTO THE NRN PLAINS STATES. LES HAS GENERALLY DISSIPATED OVER ERN LAKE SUPERIOR PER THE MQT RADAR LOOP WITH WARMER AND DRIER AIR ADVECTING INTO THE REGION. && .DISCUSSION... MAIN FCST ISSUE WILL BE STRONG WINDS TODAY WITH TIGHTENING PRES GRADIENT BTWN DEPARTED STRONG SFC HIGH PRES RIDGE AND LOW PRES TRACKING TOWARD HUDSON BAY. MODELS FORECASTING STRONG JET 65-70 KT CORE MOVING ACROSS UPPER MICHIGAN LATE THIS MORNING AND AFTERNOON WHICH SEEMS REASONABLE BASED ON UPSTREAM 00Z SOUNDINGS OVER THE NRN PLAINS AND SCNTRL CANADA. WAA PATTERN ASSOC WITH THE JET CORE WILL BE MOVING OVER A SHALLOW EXITING ARCTIC AIRMASS WHICH WILL INHIBIT MIXING AT LEAST INITIALLY TODAY. HOWEVER...MODELS SNDGS STILL PRETTY CONSISTENT INDICATING MIXING TO NEAR 950 MB BY LATE MORNING/AFTERNOON WHICH SHOULD ALLOW FAIRLY STRONG SRLY WIND GUSTS OF 40 TO 45 KT TO SFC...ESPECIALLY FOR DOWNSLOPING AREAS ALONG THE LAKE SUPERIOR SHORELINE AND EXPOSED HIGHER TERRAIN LOCATIONS. ANOTHER FACTOR SUPPORTING/ENHANCED SW WINDS WILL BE THE STRONG SFC PRES FALLS OF NEARLY 10MB/3HR SPREADING E ACROSS ONTARIO THU AHEAD OF ADVANCING SFC LOW. THUS...HAVE ISSUED A WIND ADVISORY FOR ALL COUNTIES ALONG LAKE SUPERIOR AND DOWNSTREAM OF LAKE MI...WHICH INCLUDES ALL BUT SRN HOUGHTON...IRON...DICKINSON AND MENONIMEE. GALE WARNINGS ARE ALSO POSTED FOR ALL OF LAKE SUPERIOR OPEN WATERS AND ALL OF THE NEARSHORE AREAS EXCEPT OVER HURON AND KEWEENAW BAYS AS MIXING WILL BE EVEN MORE VIGOROUS OVER UNSTABLE MARINE AREAS. MIXING TO NEAR 950 MB YIELDED HIGH TEMPS NEAR GFS MOS GUIDANCE...MID 20S INLAND TO UPR 20S ALONG GREAT LAKES SHORELINES. TONIGHT THROUGH SATURDAY...GRADIENT SLACKENS WINDS AS WINDS EVENTUALLY DECOUPLE BY LATE EVENING. SHOULD STILL BE ENOUGH OF A BOUNDARY LYR WIND (5-15 KTS) OVERNIGHT TO PREVENT TEMPS FROM FALLING MUCH.STUCK CLOSE TO GFS GUIDANCE MINS WITH LOWS IN MID TEENS INTERIOR WEST TO UPR TEENS/LOWER 20S ELSEWHERE. WENT WITH DRY WX GRIDS ALL THE WAY THROUGH SATURDAY AS THERE IS LITTLE AVAILABLE MOISTURE AND WEAK FORCING AT BEST OVER THE CWA. HIGH TEMPS WILL GRADUALLY WARM ABV FREEZING BY THE WEEKEND WITH MID TO UPR 30S EXPECTED FOR SATURDAY. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... STRONG SOUTHWEST WINDS WITH 40 KT GUSTS SHOULD CONTINUE THROUGH THE DAY...WITH REDUCTION IN VISIBILITIES DUE TO BLOWING SNOW. FOR THE MOST PART...VIS SHOULD REMAIN ABOVE 5SM IN THE BLSN. NEXT SHOT AT LOWER CLOUDS WILL ARRIVE LATE TONIGHT AS MOISTURE INCREASES BELOW 5KFT. DEVELOPMENT OF STRATUS DECK WITH INCOMING MOISTURE AND WINDS REMAINING AROUND 10 KT SHOULD PREVENT A RADIATION FOG EVENT OVER THE FRESH SNOWPACK. CIG AT KCMX WILL LIKELY BE A TOUCH LOWER THAN KSAW DUE TO ADDITIONAL MOISTURE CONTRIBUTION FROM MARINE LAYER AND GREATER RECENT SNOWFALL. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... TIGHT PRES GRADIENT DEVELOPING BTWN DEPARTING STRONG SFC HIGH PRES RIDGE AND LOW PRES TRACKING E TO HUDSON BAY RESULTS IN VERY STRONG WINDS ACROSS LK SUPERIOR NEXT 18 HR. AFTER THAT IT IS FAIRLY QUIET ON INTO EARLY NEXT WEEK WITH WINDS STAYING BLO 30 KT. BACK TO TODAY. SETUP IMPRESSIVE FOR A HIGH END GALE. AIRMASS IS NOT FULLY STABLE OVER LAKE SUPERIOR AND IMPRESSIVE PRESSURE FALLS SPREADING ACROSS ONTARIO HELP TO ENHANCE S TO SW WINDS. GUSTS TO 50 KNOTS BTWN THE KEWEENAW AND ISLE ROYALE ARE POSSIBLE THROUGH MID AFTN BUT SEEMS TOO LOCALIZED TO GO WITH STORM WARNING. WINDS DIMINISH QUICKLY THIS EVENING AS PRESSURE GRADIENT RELAXES. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST THIS EVENING FOR MIZ006-007-013-014-085. WIND ADVISORY FROM 10 AM EST /9 AM CST/ THIS MORNING TO 5 PM EST/4 PM CST/ THIS AFTERNOON FOR MIZ001>003-009. WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM EST THIS EVENING FOR MIZ004-005. LAKE SUPERIOR... GALE WARNING FROM 8 AM THIS MORNING TO 9 PM EST THIS EVENING FOR LSZ266-267. GALE WARNING FROM 8 AM THIS MORNING TO 7 PM EST THIS EVENING FOR LSZ265. GALE WARNING UNTIL 9 PM EST THIS EVENING FOR LSZ263-264. GALE WARNING FROM 8 AM THIS MORNING TO 7 PM EST THIS EVENING FOR LSZ249>251. LAKE MICHIGAN...GALE WARNING FROM 8 AM THIS MORNING TO 1 AM EST FRIDAY FOR LMZ221-248-250. && $$ SYNOPSIS/DISCUSSION...VOSS MARINE...JLA AVIATION...TAG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 331 PM CST THU JAN 3 2008 .SHORT TERM...THROUGH SUNDAY MORNING MAIN FOCUS FOR PERIOD...EFFECTS OF WAA AND MELTING SNOW PACK ACROSS THE JAMES VALLEY TONIGHT. UPPER RIDGE REMAINS OVERHEAD WITH SYSTEM DEPARTING THE PRAIRIE PROVINCES. THIS ALLOWED FOR SOUTHWEST WAA AND TEMPERATURES RANGING FROM WEST RIVER 40S TO LOW 20S OVER THE EASTERN SD SNOW PACK. MORE IMPORTANTLY...DEW POINTS HAVE RISEN INTO THE UPPER TEENS. WINDS CONTINUE TO SUBSIDE AS CANADIAN SYSTEM MOVES EAST...ALLOWING MOISTURE FROM MELTING SNOW PACK TO REMAIN. WITH LIGHT/VARIABLE WINDS TONIGHT...CLEAR SKIES...AND LOW LEVEL MOISTURE...FOG FORMATION IS A NEAR CERTAINTY. GFS/NAM/RUC ALL INDICATE NEAR SURFACE SATURATION AFTER 00Z. NEXT ISSUE IS DURATION/EVOLUTION OF FOG. IT SHOULD BE NEAR IMPOSSIBLE TO ERODE UNDER LIGHT WINDS...LOW ANGLE SUNSHINE...AND A NEARLY +10C INVERSION OVERHEAD. AGAIN...MODEL SOUNDINGS SUPPORT KEEPING SHALLOW CLOUD/FOG LAYER THROUGH SATURDAY AT WHICH POINT STRENGTHENING SOUTHWESTERLY FLOW AHEAD OF NEXT SYSTEM WILL AID IN MIXING MOISTURE OUT OF THE JAMES VALLEY. AS FOR OUR WESTERN COUNTIES...HIGHER ELEVATIONS WILL SEE SOME TRANSITORY FOG FORMATION IN VALLEY/DRAWS...MIXING OUT EASILY DUE TO WARMER TEMPERATURES. TEMPERATURES THIS PERIOD WILL VARY WIDELY WITH WARMER READINGS WEST RIVER...UNDER +5 TO +7C H7/H85 LAYER INVERSION...WHILE TEMPERATURE RANGE IN THE JAMES VALLEY WILL BE SEVERELY LIMITED WHILE FOG/STRATUS PERSISTS. SHOULD SEE A DRASTIC RISE IN TEMPERATURES FROM THE JAMES VALLEY EAST SATURDAY AS UPPER TROUGH MOVES INTO THE ROCKIES AND SOUTHWESTERLY SURFACE FLOW STRENGTHENS...ALLOWING US TO REALIZE THESE WARMER TEMPERATURES ALOFT. WILL KEEP FORECAST PERIOD DRY DESPITE A STRONG BAROCLINIC FLOW DEVELOPING SATURDAY...MAINLY DUE TO LIMITED MOISTURE IN THE H7/H85 LAYER. .LONG TERM...SUNDAY THROUGH THURSDAY MEDIUM RANGE MODELS ARE IN SOME DISARRAY THIS TIME SO CONFIDENCE IS LOW. 06Z GFS MODEL RUN SHOWED A STRENGTHENING TROUGH IN THE WEST THAT CLOSED OFF AS IT APPROACHED THIS AREA. THE UPPER LOW WENT OVER WESTERN SOUTH DAKOTA AND THE SURFACE LOW WENT THROUGH SIOUX CITY IOWA. THIS IS THE FORM OF OUR MAJOR WINTER STORMS SO IT GOT A LOT OF ATTENTION. THE 12Z GFS HAS CHANGED DIRECTIONS AND IS MORE IN LINE WITH LATEST ECMWF. LATEST MODEL RUNS SUGGEST AN H5 UPPER LEVEL TROUGH FORMING SUNDAY AND PROGRESSING EAST BY MONDAY AFTERNOON. CURRENT GRIDS HAVE A SLIGHT CHANCE OF SNOW BEGINNING SUNDAY EVENING. CURRENT MODEL RUNS SUGGEST THIS IS A LITTLE EARLY. HAVE LEFT IT IN FOR NOW BECAUSE IT IS CONSISTENT WITH SURROUNDING OFFICES AND CONFIDENCE IN TIMING OR LOCATION IS VERY LOW. A START TIME OF MONDAY MORNING WOULD BE IN LINE WITH ENSEMBLE MEANS. ENSEMBLES ALSO SHOW AN UNCERTAINTY FOR TIMING H5 TROUGH BETWEEN MEMBERS. BEHIND THIS SYSTEM THE UPPER LEVEL FLOW BECOMES MORE ZONAL WITH HIGH PRESSURE BUILDING IN AT THE SURFACE. WEDNESDAY WILL SEE NEXT CHANCE AT SOME PASSING LIGHT SNOW. TEMPERATURES WELL ABOVE NORMAL EARLY IN THE EXTENDED PERIOD WILL DROP TO NEAR NORMAL MONDAY AND SHOULD REMAIN THERE THROUGH THE PERIOD. && .AVIATION... GOOD VFR IS THE RULE ACROSS THE AREA. CEILINGS ARE UNLIMITED AND VISIBILITY IS UNRESTRICTED. TEMPERATURES ARE RISING THIS AFTERNOON AS ARE DEW POINTS AS WIND CONTINUES TO FLOW ACROSS THE SNOWFIELD. WITH FEW CLOUDS AND WHAT CLOUDS WE HAVE ARE MID TO HIGH EXPECT WITH THE END OF HEATING THIS EVENING TEMPERATURES WILL DROP QUICKLY. THIS TEMPERATURE DROP ALONG WITH THE MOISTURE IN THE AREA WILL LEAD TO LOW STRATUS AND FOG FORMATION TONIGHT. HAVE THIS SCENARIO IN THE EAST FOR TONIGHT. KPIR AND KMBG HAVE LESS SNOW COVER SO HAVE NOT BROUGHT LOW CONDITIONS IN THERE BUT WILL NEED TO MONITOR. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...CONNELLY LONG TERM...KEEFE AVIATION...KEEFE WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 325 PM CST THU JAN 3 2008 .DISCUSSION... BREEZY CONDITIONS PERSISTING OVER THE EASTERN HALF OF THE CWA THIS AFTERNOON...THOUGH WINDS HAVE BEEN EASING UP A BIT OVER THE PAST FEW HOURS AS EXPECTED. WITH PRESSURE GRADIENT DECREASING THROUGH THE EVENING HOURS...ESPECIALLY IN OUR WEST...WILL CONTINUE TO SEE WINDS FALLING OFF. KEPT PATCHY FOG OVER WESTERN PORTIONS OF THE CWA LATER TONIGHT...WHERE WINDS WILL BECOME LIGHTEST AND SNOW COVER IS STILL IN PLACE. EXTENDED THE FOG A LITTLE FARTHER WEST...WHERE THERE WAS SOME SNOW MELT TODAY ADDING MOISTURE TO THE BOUNDARY LAYER...WHICH WILL BE TRAPPED BELOW AN INVERSION TONIGHT WHILE WINDS DIE OFF AS PREVIOUSLY MENTIONED. GFS AND NAM PERSIST ON INDICATING STRATUS OVER THE NORTHEASTERN PARTS OF THE FA TONIGHT...THOUGH NOT SUPPORTED BY THE RUC...AND LEFT IT OUT OF THE GRIDS AS SEE NO PROCESSES OVER THIS AREA WHICH WOULD BE ADVECTING IN/OR CREATING A SIGNIFICANT AMOUNT OF LOW LEVEL MOISTURE. WITH WINDS DIMINISHING TONIGHT...AND A STRONG INVERSION ALOFT...WILL SEE AN ELEVATION SIGNATURE WITH REGARD TO LOWS TONIGHT...WITH LOWEST PLACES SEEING COOLEST READINGS. BIGGEST CHALLENGE THROUGH THE WEEKEND WILL BE TEMPS AND STRATUS/FOG POTENTIAL AS VERY WARM AIR ALOFT EXPANDS OVER THE AREA. MOST AREAS IN AND EAST OF THE JAMES VALLEY STILL HAVE A HEALTHY AMOUNT OF SNOW COVER...WITH MUCH LESS TO NONE WEST OF THE JAMES. EVEN WITH STRONG WARMING ALOFT AND GOOD SOUTHERLY GRADIENT WHICH TYPICALLY FAVORS GOOD MIXING...IT WILL BE TOUGH TO REALIZE MUCH OF THAT WARMING AT THE SURFACE. SOUNDINGS SUPPORT IDEA OF ISOTHERMAL MIXDOWN FROM NEAR 925MB...EXCEPT HAVE WARMED WESTERN AREAS A FEW DEGREES ABOVE THIS DUE TO BETTER INSOLATION AND LESS SNOW COVER TO DAMPEN WARMING. NAM AND GFS BOTH MAINTAIN HIGH LOW LEVEL RH ACROSS THE NORTHEAST PORTION OF THE FA. HOWEVER WITH DECENT WINDS...ESPECIALLY IN FAVORED HIGHER ELEVATION OF SWRN MN WHERE HIGHEST RH IS INDICATED...THINK WE WOULD STAND A BETTER CHANCE OF STRATUS DEVELOPMENT THAN FOG FOR FRIDAY NIGHT AND EARLY SATURDAY. MODELS CONTINUE IDEA OF WEAK UPPER WAVE SLIDING NORTHEAST ALONG TIGHTENING MID LEVEL FRONT ACROSS THE AREA LATE SUNDAY AND SUNDAY NIGHT. MAIN CONCERN WITH THIS WAVE IS SOUNDINGS MAINTAIN VERY DRY LAYER BELOW 750-800MB IN MOST AREAS. DECENT ENOUGH LOOKING WAVE THAT IT COULD OVERCOME THIS THOUGH...AND HAVE INTRODUCED SLIGHT CHANCE POPS TO CENTRAL PORTIONS OF THE AREA SUNDAY AFTERNOON...CONTINUING FOR MOST AREAS INTO SUNDAY NIGHT. THINK SURFACE TEMPS WILL BE ABLE TO WARM ABOVE FREEZING FOR SUNDAY AFTERNOON...BUT EVEN IF THEY REMAIN A SHADE BELOW FREEZING...WET BULB PROFILE THROUGH THE DRY LAYER WOULD PULL DEEP LAYER TEMPS BELOW FREEZING EXCEPT RIGHT AT THE SURFACE...SO WENT WITH RAIN/SNOW MIX WORDING FOR THIS PERIOD. BETTER CHANCE OF TRUE MEASURABLE PRECIP WILL BE IN SOUTHEAST PARTS OF THE FA SUNDAY NIGHT WHERE DEEPER MOISTURE PROFILE IS MAINTAINED. FARTHER NORTH AND WEST...SOUNDINGS INDICATE DRYING IN THE MID LEVELS ENOUGH THAT WE WOULD LOSE ICE INTRODUCTION INTO THE PRECIP LAYER. THUS HAVE CHANGE WORDING FOR THESE AREAS TO FREEZING DRIZZLE...THOUGH WILL KEEP SLIGHT CHANCE OF SNOW AS WELL WITH POTENTIAL THAT THIS MID LEVEL DRYING DOES NOT OCCUR. GOING INTO NEXT WEEK...MILD AIR REMAINS IN PLACE FOR MONDAY AHEAD OF AN APPROACHING UPPER TROUGH. CHANCES FOR PRECIPITATION WILL INCREASE AS PIECES OF UPPER ENERGY SLIDE ACROSS THE AREA. WARM TEMPERATURES ALOFT AHEAD OF THE BOUNDARY MOVING THROUGH LATE MONDAY SUPPORT RAIN OR FREEZING RAIN AS THE MAIN PRECIPITATION TYPE...ESPECIALLY IN THE SOUTHEAST PARTS OF THE CWA...WITH MODELS NOW SHOWING COOL ENOUGH AIR INTO FAR WESTERN AREAS TO ALLOW FOR PREDOMINANTLY SNOW THERE. GFS RUN TO RUN CONSISTENCY REMAINS VERY LOW WITH PLACEMENT OF SURFACE LOW AS IT EJECTS OUT OF THE CENTRAL ROCKIES EARLY IN THE WEEK. OVER THE LAST FEW DAYS...THE GFS HAS TRACKED THE LOW ANYWHERE FROM CNTRL SD TO ERN IA...AND EVENTUAL PLACEMENT OF THIS FEATURE MAKES A HUGE DIFFERENCE IN PRECIPITATION TYPE AND POPS. WITH LOW CONFIDENCE IN THE GFS AND RESULTING HIGH DEGREE OF UNCERTAINTY...HAVE STUCK PRETTY CLOSE TO HPC GUIDANCE FOR THE LONGER RANGE...WHICH FOLLOWS THE MORE CONSISTENT ECMWF AND THE SOMEWHAT SIMILAR 03/00Z OPERATIONAL GFS IN TRACKING THE PRIMARY SURFACE LOW THROUGH THE MID MISSISSIPPI RIVER VALLEY. && .AVIATION... WITH MAINLY CLEAR SKIES AND DIMINISHING WINDS TONIGHT...ALONG WITH SNOW COVER OVER THE AREA...WILL HAVE PATCHY AREAS OF MVFR FOG/VISIBILITIES AROUND THE TAF SITES AFTER 06Z. COULD SEE LOCAL VISIBILITIES DIP INTO LOW END MVFR AROUND KHON AND KFSD AFTER 09Z. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && $$ JH/JM sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1057 AM CST THU JAN 3 2008 .UPDATE... GOING FORECAST LOOKS GOOD. UPDATED TO REMOVE WORDING OF BLOWING/DRIFTING SNOW. HAVE CONTINUED TO INVESTIGATE POSSIBILITY FOR FOG/STRATUS FORMATION IN THE JAMES VALLEY/SISSETON HILLS REGION...WITH NAM/GFS STRONGLY INDICATING THE POTENTIAL. WILL CONTINUE GOING FORECAST WITH THIS FEATURE FOR NOW. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH SATURDAY NIGHT THE 500 HPA RIDGE THAT HAS BEEN EXPECTED TO ARRIVE IS NOW MOVING INTO THE PLAINS...AND STRONG WARM ADVECTION HAS OCCURRED IN THE PAST SIX OR SO HOURS WITH SOUTHERLY 925 MB WINDS AS HIGH AS 60 TO 65 KNOTS IN SOME PLACES PER THE NAM/RUC SOUNDINGS. THIS HAS ASSISTED IN NEAR WIND ADVISORY CRITERIA WINDS ACROSS THE EASTERN CWA THIS MORNING WITH BRIEF STINTS AT KATY AND K8D3 OF 30 TO 35 MPH WINDS OBSERVED. EVEN AS THE AXIS OF STRONG WINDS ALOFT PUSHES TO THE EAST...KABR IS STILL OBSERVED TO RECORD 25 MPH WINDS IN BLOWING SNOW AT 0830Z. WITH WINDS STILL EXPECTED TO REMAIN ABOVE 15 KNOTS ACROSS THE EASTERN THIRD OF THE CWA THROUGH THE FIRST PART OF THE MORNING...EXTENDED THE BLOWING SNOW MENTION THROUGH 15Z IN THESE AREAS. IN ADDITION...A WIND ADVISORY REMAINS THROUGH 12Z. WINDS ARE CURRENTLY BELOW ADVISORY CRITERIA AT ALL STATIONS ACROSS THE EAST...BUT WITH THE STRONG WINDS STILL NOT FAR ABOVE THE SURFACE...30+ MPH WINDS ARE STILL POSSIBLE SO WILL LEAVE ADVISORY RUNNING THROUGH 6AM CST. A QUIET REMAINDER OF THE SHORT TERM IS STILL IN STORE WITH THE WARMER PACIFIC AIR STILL MAKING ITS WAY INTO THE NORTHERN PLAINS. NAM/RUC FORECAST SOUNDINGS INDICATE 850 HPA TEMPERATURES RISING TO +11 TO +13 C BY LATER THIS MORNING ACROSS THE CWA ON THE HEELS OF THE STRONG WARM ADVECTION...THEN DECREASING SOMEWHAT BUT REMAINING IN THE +5 TO +10 C RANGE THROUGH THE ENTIRE SHORT TERM. THUS...WARMER THAN NORMAL TEMPERATURES ARE EXPECTED OVER MOST OF THE AREA THE NEXT FEW DAYS. THE WARMEST DAY APPEARS TO BE SATURDAY...AS WINDS WILL BE RELATIVELY LIGHT TODAY AND FRIDAY WITH LIMITED MIXING...BUT MORE MIXING SHOULD OCCUR ON SATURDAY TO BRING DOWN STRONGER WINDS...LIMITING CLOUD POTENTIAL AND INCREASING THE POTENTIAL FOR WARMER TEMPERATURES. MET GUIDANCE SUGGESTS NEAR RECORD HIGH TEMPERATURES ON SATURDAY IN THE 40S AND 50S...PARTICULARLY IN THE WESTERN CWA...SO THIS WILL BE SOMETHING TO KEEP AN EYE ON FOR MAXIMUM TEMPERATURES. ACROSS THE EASTERN CWA...THERE IS STILL SOME INTEREST IN FOG POTENTIAL THIS EVENING THROUGH SATURDAY MORNING. 00Z NAM SOUNDINGS CONTINUE TO INDICATE STRONG WARM ADVECTION OVER THE SURFACE LEADING TO A DEEP LAYER ABOVE FREEZING ALOFT...BUT A LARGE INVERSION JUST ABOVE THE SURFACE WITH MOISTURE TRAPPED BENEATH IT DUE TO THE CURRENT SNOW COVER AS WELL AS MOISTURE ADVECTION FROM THE SOUTH. THE SOUNDINGS ALSO INDICATE WIDESPREAD LOW STRATUS/POSSIBLE FOG UNDER THE INVERSION...WITH TEMPERATURES AT THE SURFACE REMAINING RATHER COOL RELATIVE TO THE WARM AIR ALOFT. THE 00Z GFS IS SIMILAR IN SHOWING A VERY LARGE INVERSION...THOUGH IT IS NOT AS STRONG WITH THE WARM AIR ALOFT AND LOW LEVEL MOISTURE. HOWEVER...GIVEN THE COARSER RESOLUTION OF THE GFS IN THE BOUNDARY LAYER...NOT SURPRISED TO SEE THIS. THE NAM ALSO INDICATES LIGHT TO NO WINDS NEAR THE SURFACE UNDER THE INVERSION FOR MUCH OF THIS 36 HOUR TIME PERIOD FROM 00Z FRIDAY TO 12Z SATURDAY...AND OCCASIONALLY DEPICTS LITTLE TO NO WIND ALL THE WAY UP TO 800 HPA AS WELL. THOUGH THE GFS HAS A BIT STRONGER WINDS...POSSIBLY DUE IN PART TO THE COARSER BOUNDARY LAYER RESOLUTION...THINK THAT IF THE INVERSION DOES SET UP AS STRONG AS BOTH MODELS SUGGEST...EVEN IF THE WINDS ARE A BIT STRONGER THEY MAY SIMPLY FLOW OVER THE INVERSION WITH LITTLE AIR MOVEMENT AT THE SURFACE BELOW IT. THUS...FEEL IT IS A GOOD IDEA TO MENTION THE POSSIBILITY OF FOG IN THE GRIDS AT THIS POINT...EVEN THOUGH EXACT TIMING IS STILL RELATIVELY UNCLEAR. ANY FOG THAT WOULD FORM WOULD GREATLY INFLUENCE TEMPERATURES...AS WELL AS HELP MAINTAIN THE INVERSION...SO LOWERED HIGHS A BIT IN THE EAST TO ACCOUNT FOR THIS POSSIBILITY. ACROSS THE EAST ON SATURDAY...TEMPERATURES SHOULD BE ABLE TO RISE INTO THE 30S AND POSSIBLY 40S IN AREAS AS INCREASED MIXING LEADS TO STRONGER SURFACE WINDS...PREVENTING FOG POTENTIAL AND TAPPING INTO WARMER AIR ABOVE THE SURFACE. .LONG TERM...SUNDAY THROUGH WEDNESDAY MAIN CHALLENGE IN THE EXTENDED CONTINUES TO BE THE INCONSISTENCY BETWEEN MODEL SOLUTIONS. THE UPPER LEVEL PATTERN WILL START OFF FEATURING A BROAD TROUGH OVER THE WESTERN HALF OF THE COUNTRY...AND A RIDGE OVER THE EAST. THE GFS SLIDES THE TROUGH TO THE ROCKIES BY TUESDAY MORNING...THEN HAS IT MERGING WITH ANOTHER TROUGH TO THE NORTHWEST TUESDAY NIGHT AND BECOMING SITUATED OVER THE PLAINS ON WEDNESDAY. THE ECMWF IS MUCH FASTER...PUSHING THE TROUGH TO THE PLAINS BY TUESDAY MORNING...THEN QUICKLY EASTWARD AND NEVER MERGING WITH THE NEXT TROUGH...THOUGH THAT TROUGH DOES MOVE OVER THE PLAINS WEDNESDAY. AT THE SURFACE...GOOD AGREEMENT AMONGST THE MODELS OF A TROUGH OVER THE PLAINS EARLY SUNDAY AND WEAK HIGH PRESSURE BUILDING OVER THE AREA SUNDAY EVENING...AND THAT IS WHERE ANY REASONABLE AGREEMENT ENDS. THE GFS SHOWS A LOW PRESSURE SYSTEM TRACKING FROM EASTERN COLORADO SUNDAY EVENING TO WISCONSIN BY MONDAY EVENING...WITH PRECIPITATION OVER THE CWA MUCH OF MONDAY. THE ECMWF HAS A MUCH WEAKER FASTER MOVING LOW WITH LITTLE IN THE WAY OF PRECIPITATION. THE DIFFERENCES IN TIMING CONTINUES THROUGH THE END OF THE PERIOD AS THE ECMWF TRACKS HIGH PRESSURE ACROSS THE AREA ON WEDNESDAY AND THE GFS IS ABOUT 12 HOURS BEHIND. CURRENT MODEL DISCREPANCIES APPEAR TO GET EVEN WORSE PAST THE END OF THE LONG TERM PERIOD. SO...BASICALLY CHANGED VERY LITTLE IN THE EXTENDED WITH THE EXCEPTION OF PRECIPITATION SUNDAY NIGHT AND MONDAY. AFTER PERUSING THROUGH GFS FORECAST SOUNDINGS...IT APPEARS THERE WILL BE A FAIRLY DECENT LAYER OF WARM AIR ALOFT THAT COULD RESULT IN PRECIPITATION BEGINNING AS FREEZING RAIN SUNDAY NIGHT...AND HAVE SPREAD THAT CHANCE FURTHER WEST THAN THE PREVIOUS FORECAST INDICATED. SOUNDINGS ALSO INDICATING THE COOLER AIR TAKING OVER SOONER ON MONDAY...SO WENT WITH ALL SNOW IN THE NORTH AND A POSSIBLE MIX OF RAIN OR SNOW ACROSS THE SOUTH. BY MONDAY NIGHT...ANY CONTINUING PRECIPITATION SHOULD BE ALL SNOW. DRY CONDITIONS EXPECTED TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES IN BEHIND THE EXITING LOW. TEMPERATURES WILL STILL BE FAIRLY MILD ON SUNDAY AS WEAK WAA CONTINUES AND H85 TEMPS REMAIN JUST ABOVE ZERO. THE COOLER AIR BEGINS TO GET PULLED INTO THE REGION EARLY MONDAY...WITH H85 TEMPS IN THE SINGLE DIGITS BELOW ZERO FROM MONDAY EVENING ONWARD. WENT WITH A SLIGHT COOLING TREND MONDAY THROUGH WEDNESDAY...THOUGH TEMPS LOOK TO BE NEAR OF JUST ABOVE NORMAL. && .AVIATION... GUSTY SOUTH WINDS OF 20 TO 30 MPH WILL CONTINUE EARLY THIS MORNING FROM THE JAMES RIVER VALLEY EASTWARD...MAINLY AFFECTING KABR...KATY AND K8D3. VSBYS MAY FALL TO AROUND 2SM AT TIMES DUE TO BLOWING SNOW...MAINLY ALONG AND EAST OF INTERSTATE 29. THE STRONG WINDS...AND THE POTENTIAL FOR BLOWING SNOW... WILL SUBSIDE AFTER 12Z. VFR CONDITIONS WILL THEN PREVAIL ACROSS THE ENTIRE CWA WITH SCT-BKN HIGH CLOUDS AOA 20K FEET STREAMING ACROSS THE REGION. VSBYS WILL BE UNRESTRICTED. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CONNELLY SHORT TERM...ECKSTEIN LONG TERM...PARKIN AVIATION...PARKIN WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1045 AM CST THU JAN 3 2008 .DISCUSSION... WITH WINDS CONTINUING TO MEET ADVISORY CRITERIA OVER SOUTHWESTERN MINNESOTA...WENT AHEAD AND EXTENDED WIND ADVISORY THROUGH 18Z OVER THIS AREA. BOTH RUC AND NAM HAVE CAA/PRESSURE GRADIENT/925 MB WIND SPEEDS DECREASING OVER THIS PORTION OF THE CWA THROUGH THE AFTERNOON...AND THIS IS SUPPORTED BY LATEST WDL PROFILER DATA AND SFC OBS...SO EXPECT WINDS TO CONTINUE TO DIMINISH AFTER THIS TIME. REMAINDER OF FORECAST LOOKS OKAY...WITH HIGH TEMPERATURES LOOKING TO BE ON TRACK WITH LATEST BUFKIT SOUNDINGS SUGGESTING MIXING TO 925 MB...WHICH WOULD YIELD HIGHS SIMILAR TO WHAT WE HAVE GOING. MINOR UPDATES SENT OUT. /JM .PREV DISCUSSION... IN THE NEAR TERM...DECIDED TO GO AHEAD AND ISSUE A WIND ADVY FOR NEARLY ALL OF SW MN AND BROOKINGS CO. VERY TIGHT SFC PRS GRADIENT AND WINDS ALOFT AT H925 AT 55 TO 60 KTS IN THAT AREA THRU 15Z. INTERESTINGLY...MESOSCALE CAA HAS SETUP ALONG THE BUFFALO RIDGE THIS MORNING...PICKING UP THE SUBTLE HIGHER TERRAIN AS THE LOW LEVEL FLOW ASCENDS. AS OF 08Z...THE WDL PROFILE IS NOW AT 45 KTS AND INCREASING...AND A COUPLE OF SPOTS IN SW MN ARE ALREADY AT WIND ADVY CRITERIA. HOWEVER AFT 15Z...THE STRONGEST WINDS ALOFT BEGIN TO SHIFT OFF TO THE SE OF THIS AREA...SO WANTED THE ADVY ONLY RUNNING UNTIL 10 AM. OTHERWISE TODAY WL SEE MILDER TEMPS WITH THE SLY FLOW. HIGH LEVEL PAC MSTR WL CONT TO STREAM INTO THE FA FM THE WEST...BUT SHOULD NOT HINDER TEMPS. NAM/GFS BEGIN TO PAINT VERY HIGH LEVELS OF RH NEAR THE SFC TODAY THRU MUCH OF THE FA...ALONG AND E OF THE JAMES RIVER VALLEY. ATTM...OPTED NOT TO INCLUDE ANY STRATUS IN THE GRIDS AS LOW LEVEL DEWPTS ARE STILL RATHER DRY TO OUR SOUTH BECAUSE OF THE HUGE...COOL SFC ANTICYCLONE GRUDGINGLY MOVG OFF TO THE EAST THRU THE ERN CONUS. SO WERE NOT REALLY ADVECTING ANY LOW LEVEL MSTR IN. ALSO...SNOW MELT WL LIKELY NOT BE REAL INTENSE YET TODAY DUE TO THE RELATIVELY DRY SFC AIR AND ANTICIPATED TEMPS STAYING AOB FREEZING ALONG AND E OF THE JAMES. WL MONITOR HOWEVER. SNDGS ARE MIXED A BIT TODAY...AROUND H925. SO BUMPED UP OUR GOING HIGHS ABOUT 2 DEGS GIVEN CURRENT PROGGED H925 TEMPS ON THE MODELS. WINDS SLACKEN OFF TONIGHT...BOTH AT THE SFC AND ALOFT. THEREFORE KEPT THINGS A BIT CHILLY IN THE LOW LYING AREAS. THE LIGHTEST FLOW IS IN THE WRN FA SO OPTED TO PUT IN A MENTION OF FOG IN THE JAMES RIVER VALLEY OVER THE SNOW COVER. ON FRIDAY...S/W ENERGY MOVES THRU THE AREA LATE IN THE DAY AND FRI EVENING ACTING TO INCREASE THE MID AND HIGH LEVEL MSTR. H925 TEMPS ARE WARMER YET...AND A FAIR AMNT WARMER ON THE NAM AS COMPARED TO THE GFS. SO FOR MAX TEMP GUIDANCE...OPTED TO COMPROMISE BETWEEN THE TWO SOLNS AS MANY TIMES THE NAM WARMS THINGS UP TOO QUICKLY OFF THE SFC...BUT THE GFS CAN ALSO BE TOO COOL. SNDGS ARE TOTALLY INVERTED ON FRIDAY WITH NO MIXING. SO GOING ISOTHERMAL FM H925 LOOKED LIKE A GOOD FCST. THIS TREND CONTS FRI NIGHT AND SAT...WITH NO MIXING DUE TO A LARGE THERMAL INVERSION IN PLACE. SFC PRS GRAD AND WIND ALOFT BEGIN TO PICK UP STEAM AGAIN LATE FRI AFTN...LASTING THRU THE NIGHT AND INTO SATURDAY. THEREFORE OPTED TO LEAVE FOG WORDING OUT OF THE FA FOR NOW FRI NIGHT/SAT DUE TO THE INCREASE IN SLY WINDS. BUT WL MONITOR TO SEE IF ERN NEB BEGINS TO DEVELOP FOG/STRATUS WHICH THE SLY FLOW WOULD ADVECT UP HERE. SNOW MELT MOISTURE MAY GET BLOWN APART AS THE LOW LEVEL AIR CERTAINLY IS NOT DEAD FRI NIGHT/SAT LIKE IT WAS AROUND CHRISTMAS. WITH ANTICIPATED H925 TEMPS...OUR SW CWFA WL LIKELY GET VERY MILD FRI AND SAT WHICH SHOULD PUT AN END TO THEIR SNOW COVER. DID NOT ALTER PCPN CHCS FURTHER OUT ON SUN AND MON. QUICK GLANCE AT THE 00Z ECMWF SHOWS SOME PCPN DEVELOPMENT OVR THE NRN AND WRN PTNS OF OUR FA ON SUNDAY ALONG A MID LVL BAROCLINIC ZONE WITH STRONG MID LVL FRONTOGENESIS. ECWMF COMES IN TOO LATE TO FULLY ANALYZE ON THIS SHIFT...BUT THE DAYSHIFT MAY WANT TO ADD A WINTERY MIX IN THESE AREAS ON SUNDAY IF THEY CHOOSE TO DO SO. && .AVIATION... VFR CONDITIONS SHOULD PREVAIL FOR MOST OF THE PERIOD THRU 12Z FRI. MOST SIGNIFICANT SHORT TERM CONCERN IS THE LOW LVL WIND SHEAR DUE TO INTENSE INVERSION. MAX PRESSURE FALLS AT 09Z APPEAR TO BE ALONG THE I29 CORRIDOR OF SERN SD INTO WRN MN. WDL PROFILER INDICATES A QUICK PICKUP TO 45 KTS AT INITIAL GATE OFF SFC...AND MODEL INVERSIONS SUGGEST IN AND ARND 1KFT WHERE SOME STRONGER VERTICAL WIND GRADIENT EXISTS. WL CONTINUE SOME LLWS MENTION INTO EARLY MORNING FOR ALL SITES...BUT THREAT WL DIMINISH FOR KHON SHORTLY AFT 12Z...14Z AT KFSD...AND 16Z WHERE LOW LVL WNDS A BIT MORE SLUGGISH TO RESPOND THUSFAR AT KSUX. OTHERWISE...AT THE MOMENT...STRATUS POTENTIAL LOOKS OVERDONE IN MDLS CONSIDERING THE LACK OF AVAILABLE MOISTURE BLO INTENSE INVERSION...AS HAVE YET TO HAVE A GOOD MELTING DAY TO INCREASE BL MOISTURE. DOES APPEAR TO BE A BETTER THREAT FOR FOG DEVELOPMENT 06Z-12Z FRI THRU THE JAMES VALLEY AS SFC GRADIENT WKNS AND GET A FIRST DAY OF MELT UNDER THE BELT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...WIND ADVY UNTIL 10 AM THIS MORNING FOR SDZ040. MN...WIND ADVY UNTIL 10 AM THIS MORNING FOR MNZ071-072-080-081- 089-090-097. IA...NONE. NE...NONE. && $$ MJF/CHAPMAN sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SPOKANE WA 1011 AM PST THU JAN 3 2008 .SYNOPSIS... AN ACTIVE WINTER WEATHER PATTERN WILL RETURN TO THE REGION TODAY AND TONIGHT WITH MORE WIDESPREAD MINOR ACCUMULATIONS OF SNOW...AND EVEN SLEET OR FREEZING RAIN. OVER THE NEXT FEW DAYS SNOW LEVELS WILL GRADUALLY RISE WITH VALLEY RAIN BECOMING COMMON BY FRIDAY...WHILE MOUNTAIN SNOW CONTINUES THROUGH THE REMAINDER OF THE WORK WEEK. && .DISCUSSION... REST OF TODAY...A LONG-WAVE TROUGH REMAINS OFF THE COAST WITH A COUPLE SHORT-WAVE FEATURES EMBEDDED IN A MEAN SW FLOW. ONE WEAK WAVE IS EXITING THE AREA...SKIRTING OVER THE SOUTHEAST HALF OF THE CWA. A SECOND STRONGER WAVE...EASILY IDENTIFIABLE ON WV/IR IMAGERY...IS APPROACHING THE PAC NW COAST AND WILL BEGIN TO AFFECT THE WEATHER LATE TODAY. CLOSING INTO THE REGION...A WARM IS DRAPED ACROSS THE CENTRAL WASHINGTON AND BROAD AREA OF WAA IS FOUND IN ABOUT THE 900-800 MB LAYER. ISENTROPIC LIFT IS FOUND IN THE 290-300K LAYER ACROSS THE WEST AND NORTHEAST CWA THIS MORNING AND IS EXPECTED TO PERSIST...THOUGH IT CAN MAINLY DESCRIBED AS WEAK WITH ONLY A GRADUAL SLOPE IN THE ISENTROPIC SFC. SOME STRONGER LIFT BEGINS TO MOVE ONTO THE WEST CWA LATE TODAY AS THE SECOND SHORT-WAVE BEGINS TO MOVE IN. MOISTURE IS REASONABLY DEEP OVER THE CWA...SAVE FOR THE SE CWA WHERE A GREATER DRY LAYER EXISTS AROUND THE 900-800 LAYER. THUS THE BEST RISK FOR PRECIP WILL CONTINUE OVER THE WEST AND NORTHERN CWA...WITH THE FOCUS GRADUALLY STARTING TO SHIFT NORTHWEST. HOURLY PRECIP RATES ARE NOT IMPRESSIVE ATTM. RADAR...HOWEVER...SHOWS AN AREA OF PRECIP AHEAD OF THE NEXT WAVE MOVING TOWARD THE SOUTHWEST CWA THIS HOUR AND WILL ALLOW TO AN INCREASE IN PRECIP ACROSS THE WESTERN HALF OF THE CWA THROUGH THIS AFTERNOON. THERE IS NEXT THE CONSIDERATIONS FOR PRECIP-TYPE. THIS MORNING`S SOUNDING SHOWS A SWATH OF ABOVE MILD (ABOVE FREEZING) AIR ALOFT...PEAKING NEAR 875 MB. MODELS SHOW THIS WARM SLOT...BUT ARE HAVING SOME TROUBLE WITH THE DETAILS. THE NAM IS A BIT OVERDONE (TOO MILD) WITH THAT LAYER...THE GFS IS A BIT BETTER. BOTH ARE NOT DOING WELL WITH THE BL PROFILE...THOUGH THE NAM/RUC IS CLOSEST. WHERE THIS MILDER TONGUE MOVES OVER THE COLDER SFC IS WHERE THE MIXED PRECIP THREAT WOULD BE. SFC TEMPS ARE GRADUALLY WARMING ACROSS THE UPPER COLUMBIA BASIN AND MOSES LAKE ZONE. THESE SFC TEMPS AREAS ARE EXPECTED TO CONTINUE TO WARM. THOUGH NOT ALL AREAS WILL WARM ABOVE FREEZING AND THERE MAY BE SOME MIXED OF -IP/-FZRA WHEN THE PRECIP INCREASES THROUGH THE AFTERNOON...THE AREA LOOKS SMALL. THUS THE WINTER WEATHER ADVISORIES WILL BE ALLOWED TO EXPIRE. IN ADDITION...THE SNOW ADVISORIES OVER THE NE WA AND NRN PANHANDLE ARE ALSO ALLOWED TO EXPIRE...AS ADDITIONAL ACCUMULATIONS SHOULD REMAIN UNDER 2 INCHES IN MOST AREAS (THOUGH ISOLATED HIGHER AMOUNTS ARE POSSIBLE NEAR THE CANADIAN BORDER). SNOW ADVISORIES TO THE WEST OF HERE WILL CONTINUE. UPDATED FORECAST SENT...WITH SOME ADJUSTMENTS TO TEMPS TOO. /J && .AVIATION... A PACIFIC STORM WILL PASS THROUGH THE REGION TODAY THROUGH TONIGHT. OVER THE COLUMBIA BASIN SOUTH OF INTERSTATE 90 INCLUDING THE KMWH KPUW AND KLWS TAF SITES MAINLY VFR CONDITIONS ARE EXPECTED WITH OCCASIONAL MVFR CEILINGS IN RAIN. OVER THE COLUMBIA BASIN NORTH OF INTERSTATE 90 MAINLY MVFR CEILINGS IN RAIN ARE EXPECTED...EXCEPT FOR KEAT WHERE PERSISTANT LOW LEVEL COLD AIR WILL PROMOTE PERIODS IFR CONDITIONS IN LOW CLOUDS AND SNOW THROUGH 18Z FRIDAY. THE MOUNTAINS RINGING THE COLUMBIA BASIN WILL REMAIN OBSCURED IN CLOUDS AND PCPN THROUGH 18Z FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 35 32 38 34 36 27 / 50 80 80 70 30 20 COEUR D`ALENE 35 32 39 34 35 27 / 60 80 80 80 40 40 PULLMAN 39 36 42 36 39 31 / 30 70 80 60 30 20 LEWISTON 44 39 48 39 44 33 / 20 50 60 50 30 20 COLVILLE 30 31 37 36 36 28 / 80 90 80 80 60 30 SANDPOINT 30 30 35 35 35 25 / 80 80 80 80 60 40 KELLOGG 34 31 38 34 35 26 / 60 80 80 70 60 40 MOSES LAKE 34 33 42 36 38 25 / 60 60 80 50 20 20 WENATCHEE 31 29 34 34 34 25 / 70 80 80 60 30 20 OMAK 31 28 33 33 33 24 / 90 80 80 80 40 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...SNOW ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR WATERVILLE PLATEAU...WENATCHEE AREA. SNOW ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR OKANOGAN HIGHLANDS...OKANOGAN VALLEY. && $$ wa