AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CHARLESTON SC 739 AM EST WED JAN 10 2007 .UPDATE...WINDS ARE SLOWLY SUBSIDING ON LAKE MOULTRIE THIS MORNING. THE LATEST OBSERVATIONS AT PINEVILLE SHOW WINDS HAVE DROPPED BELOW LAKE WIND ADVISORY CRITERIA...BUT JUST BARELY. UPDATED PRODUCTS WILL BE ISSUED SHORTLY TO REMOVE THE LAKE WIND ADVISORY HEADLINE. && .PREV DISCUSSION... /ISSUED 310 AM EST WED JAN 10 2007/ SHORT TERM /TODAY THROUGH FRIDAY/...CURRENTLY AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER THE LOWER MS VALLEY...WITH RIDGING EXTENDING EASTWARD INTO THE SOUTHEAST CONUS. THIS HAS RESULTED IN CLEAR SKIES ACROSS THE ENTIRE FORECAST AREA AS SEEN IN IR SAT IMAGERY. MAIN SHORT TERM CONCERN FOR TODAY REVOLVES AROUND MAX TEMPERATURES. TODAY...HIGH PRESSURE WILL CONTINUE TO BUILD EASTWARD INTO THE FORECAST AREA THROUGH THE DAY...RESULTING IN SUNNY SKIES. AS FOR TEMPERATURES...LOW LEVEL THICKNESS VALUES SUGGEST HIGHS AROUND 50 TO LOWER 50S ACROSS THE AREA. WITH FULL SUN...A WELL MIXED ATMOSPHERE...AND A MODERATING AIRMASS...SHOULD SEE HIGHS TOP OUT GENERALLY IN THE MID 50S. TONIGHT AND THURSDAY...HIGH PRESSURE WILL SHIFT NORTHEASTWARD INTO THE MID-ATLANTIC REGION TONIGHT...THEN OFF THE MID-ATLANTIC COAST ON THURSDAY. CLEAR SKIES AND LIGHT/CALM WINDS WILL RESULT IN EXCELLENT RADIATIONAL COOLING ACROSS THE AREA TONIGHT. OVERNIGHT LOWS SHOULD BOTTOM OUT IN THE MID TO UPPER 20S...WITH LOWS IN THE MID 30S TO AROUND 40 DEGREES CLOSER TO THE COAST. WILL MENTION SCATTERED FROST FOR COASTAL ZONES AWAY FROM THE IMMEDIATE COAST...WITH WIDESPREAD FROST INLAND. WINDS WILL BECOME MORE ONSHORE THURSDAY ALLOWING LOW LEVEL MOISTURE TO INCREASE ACROSS THE AREA. EXPECT MOSTLY SUNNY CONDITIONS ACROSS INTERIOR SC ZONES THROUGH THE DAY...WITH SKIES BECOMING PARTLY CLOUDY ACROSS SE GA AND ALL COASTAL ZONES IN THE AFTERNOON. HIGH TEMPERATURES ARE EXPECTED TO TOP OUT GENERALLY AROUND 60 DEGREES. THURSDAY NIGHT AND FRIDAY...A COASTAL TROUGH IS EXPECTED TO SET UP OFF THE SC/GA COAST...AND WITH ONSHORE FLOW CONTINUING ACROSS THE AREA...LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE. HAVE INTRODUCED SOME SLGT CHC POPS ACROSS COASTAL ZONES AFTER MIDNIGHT THU THROUGH THE MORNING HOURS FRI FOR SOME LIGHT SHOWERS ROLLING IN OFF THE ATLANTIC. BY FRI AFTERNOON...ATLANTIC HIGH PRESSURE WILL BEGIN TO BUILD BACK TOWARD THE FORECAST AREA...AND ALTHOUGH A FEW SHOWERS CAN/T BE RULED OUT...WILL HOLD OFF ON MENTIONING ANY SHOWER ACTIVITY FOR NOW. OVERNIGHT LOWS THURSDAY WILL RANGE FROM AROUND 40 WELL INLAND TO THE UPPER 40S TO AROUND 50 NEAR THE COAST. HIGH TEMPERATURES FRIDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 60S. LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...NO CHANGES MADE TO THE EXTENDED PERIOD WITH THE MORNING PACKAGE. FIRE WEATHER...CRITICAL RH VALUES ARE EXPECTED ONCE AGAIN TODAY AWAY FROM THE IMMEDIATE COAST...AND WILL HEADLINE CRITICAL RH VALUES IN THE MORNING FIRE WEATHER FORECAST. MARINE...WNDS HAVE GENERALLY PEAKED ACROSS THE WTRS EARLY THIS MRNG WITH THE INTENSITY OF CAA SHOWING SIGNS OF SLACKING OFF. STILL SOLID SCA CONDITIONS ARE IN PROGRESS WITH WNDS GENERALLY 20-25 KT AWAY FROM THE BEACHES AND CLOSER TO 25-30 KT OVR THE GA OFFSHORE WTRS. WL MAINTAIN THE SCA FOR ALL NEARSHORE WTRS INCLUDING CHARLESTON HARBOR THROUGH MID-MRNG...AFTER WHICH THE FLAGS WL LIKELY BE DROPPED. HAVE ONLY HAD ONLY A FEW GUSTS TO GALE FORCE REPORTED AT SPAG1 OVR THE PAST FEW HRS SO SUSPECT THE RISK FOR GALES HAS PASSED. THE GALE WRNG WL THEREFORE BE DOWNGRADED TO AN SCA. HIGH PRES OVR THE LWR MS VALLEY WL SHIFT E INTO NC THU AND OFF THE MID-ATLC COAST BY FRI. THIS SHOULD HELP INDUCE A SHARP COASTAL TROF OFF THE SC/GA COAST BEGINNING AS EARLY AS TNGT. THIS WL BRING PINCHED GRADIENT CONDITIONS TO THE MARINE AREA THROUGH FRI. AN AREA OF LOCALLY ENHANCED WNDS WL LIKELY SETUP SOMEWHERE ACROSS THE COASTAL WTRS WHERE GRADIENT PINCHING IS MAXIMIZED BUT UNTIL THE TROF DVLPS PINNING DOWN WHERE THESE WNDS WL MATERIALIZE WL BE TRICKY. FOR NOW WL TREND WNDS UPWARD TO A SOLID 15 KT ACROSS THE NEARSHORE WTRS WITH 15-20 KT ACROSS THE GA OFFSHORE WTRS AND BUILD SEAS 1-2 FT ABV WW3 GUIDANCE. WL ALSO DELAY THE ONSET OF VEERING WNDS FRI AS THE MODELS ARE TYPICALLY TOO QUICKLY IN BRINGING COASTAL TROFS ONSHORE. IT DOES APPEAR AS THOUGH AN EXTENDED PERIOD OF SCA CONDITIONS ARE LIKELY TO OCCUR OVR THE GA OFFSHORE WTRS AND MAY VERY WELL OCCUR OVR THE NEARSHORE WTRS. AVIATION /06Z-06Z/...WNDS HAVE PARTIALLY DECOUPLED AT BOTH TAF SITES BUT WNDS AROUND 1200 FT REMAIN NEAR 30 KT. WL NEED TO KEEP MENTION OF LLWS GOING THROUGH AT LEAST 14Z AFT WHICH SFC WNDS WL BEGIN TO INCR AS WNDS ALOFT SLOWLY DECR. VFR CONDITIONS WL PREVAIL FOR THE NXT 24 HRS. LAKE WINDS...THE LATEST OBSERVATIONS FROM PINEVILLE INDICATE SOLID LAKE WIND ADVISORY CONDITIONS ARE IN PROGRESS. THE LATEST RUC AND NAM OUTPUT SUGGESTS 975MB WNDS WL SURGE A BIT BTWN 09-12Z SO WL NEED TO EXTEND THE LAKE WIND ADVISORY THROUGH 8 AM...AFT WHICH A STEADY DECR IN SPEEDS WL OCCUR. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330- 350-352-354. SMALL CRAFT ADVISORY UNTIL 5 PM EST SUNDAY FOR AMZ374. && $$ ST ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 310 AM EST WED JAN 10 2007 .SHORT TERM /TODAY THROUGH FRIDAY/...CURRENTLY AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER THE LOWER MS VALLEY...WITH RIDGING EXTENDING EASTWARD INTO THE SOUTHEAST CONUS. THIS HAS RESULTED IN CLEAR SKIES ACROSS THE ENTIRE FORECAST AREA AS SEEN IN IR SAT IMAGERY. MAIN SHORT TERM CONCERN FOR TODAY REVOLVES AROUND MAX TEMPERATURES. TODAY...HIGH PRESSURE WILL CONTINUE TO BUILD EASTWARD INTO THE FORECAST AREA THROUGH THE DAY...RESULTING IN SUNNY SKIES. AS FOR TEMPERATURES...LOW LEVEL THICKNESS VALUES SUGGEST HIGHS AROUND 50 TO LOWER 50S ACROSS THE AREA. WITH FULL SUN...A WELL MIXED ATMOSPHERE...AND A MODERATING AIRMASS...SHOULD SEE HIGHS TOP OUT GENERALLY IN THE MID 50S. TONIGHT AND THURSDAY...HIGH PRESSURE WILL SHIFT NORTHEASTWARD INTO THE MID-ATLANTIC REGION TONIGHT...THEN OFF THE MID-ATLANTIC COAST ON THURSDAY. CLEAR SKIES AND LIGHT/CALM WINDS WILL RESULT IN EXCELLENT RADIATIONAL COOLING ACROSS THE AREA TONIGHT. OVERNIGHT LOWS SHOULD BOTTOM OUT IN THE MID TO UPPER 20S...WITH LOWS IN THE MID 30S TO AROUND 40 DEGREES CLOSER TO THE COAST. WILL MENTION SCATTERED FROST FOR COASTAL ZONES AWAY FROM THE IMMEDIATE COAST...WITH WIDESPREAD FROST INLAND. WINDS WILL BECOME MORE ONSHORE THURSDAY ALLOWING LOW LEVEL MOISTURE TO INCREASE ACROSS THE AREA. EXPECT MOSTLY SUNNY CONDITIONS ACROSS INTERIOR SC ZONES THROUGH THE DAY...WITH SKIES BECOMING PARTLY CLOUDY ACROSS SE GA AND ALL COASTAL ZONES IN THE AFTERNOON. HIGH TEMPERATURES ARE EXPECTED TO TOP OUT GENERALLY AROUND 60 DEGREES. THURSDAY NIGHT AND FRIDAY...A COASTAL TROUGH IS EXPECTED TO SET UP OFF THE SC/GA COAST...AND WITH ONSHORE FLOW CONTINUING ACROSS THE AREA...LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE. HAVE INTRODUCED SOME SLGT CHC POPS ACROSS COASTAL ZONES AFTER MIDNIGHT THU THROUGH THE MORNING HOURS FRI FOR SOME LIGHT SHOWERS ROLLING IN OFF THE ATLANTIC. BY FRI AFTERNOON...ATLANTIC HIGH PRESSURE WILL BEGIN TO BUILD BACK TOWARD THE FORECAST AREA...AND ALTHOUGH A FEW SHOWERS CAN/T BE RULED OUT...WILL HOLD OFF ON MENTIONING ANY SHOWER ACTIVITY FOR NOW. OVERNIGHT LOWS THURSDAY WILL RANGE FROM AROUND 40 WELL INLAND TO THE UPPER 40S TO AROUND 50 NEAR THE COAST. HIGH TEMPERATURES FRIDAY ARE EXPECTED TO TOP OUT IN THE MID TO UPPER 60S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...NO CHANGES MADE TO THE EXTENDED PERIOD WITH THE MORNING PACKAGE. && .FIRE WEATHER...CRITICAL RH VALUES ARE EXPECTED ONCE AGAIN TODAY AWAY FROM THE IMMEDIATE COAST...AND WILL HEADLINE CRITICAL RH VALUES IN THE MORNING FIRE WEATHER FORECAST. && .MARINE...WNDS HAVE GENERALLY PEAKED ACROSS THE WTRS EARLY THIS MRNG WITH THE INTENSITY OF CAA SHOWING SIGNS OF SLACKING OFF. STILL SOLID SCA CONDITIONS ARE IN PROGRESS WITH WNDS GENERALLY 20-25 KT AWAY FROM THE BEACHES AND CLOSER TO 25-30 KT OVR THE GA OFFSHORE WTRS. WL MAINTAIN THE SCA FOR ALL NEARSHORE WTRS INCLUDING CHARLESTON HARBOR THROUGH MID-MRNG...AFTER WHICH THE FLAGS WL LIKELY BE DROPPED. HAVE ONLY HAD ONLY A FEW GUSTS TO GALE FORCE REPORTED AT SPAG1 OVR THE PAST FEW HRS SO SUSPECT THE RISK FOR GALES HAS PASSED. THE GALE WRNG WL THEREFORE BE DOWNGRADED TO AN SCA. HIGH PRES OVR THE LWR MS VALLEY WL SHIFT E INTO NC THU AND OFF THE MID-ATLC COAST BY FRI. THIS SHOULD HELP INDUCE A SHARP COASTAL TROF OFF THE SC/GA COAST BEGINNING AS EARLY AS TNGT. THIS WL BRING PINCHED GRADIENT CONDITIONS TO THE MARINE AREA THROUGH FRI. AN AREA OF LOCALLY ENHANCED WNDS WL LIKELY SETUP SOMEWHERE ACROSS THE COASTAL WTRS WHERE GRADIENT PINCHING IS MAXIMIZED BUT UNTIL THE TROF DVLPS PINNING DOWN WHERE THESE WNDS WL MATERIALIZE WL BE TRICKY. FOR NOW WL TREND WNDS UPWARD TO A SOLID 15 KT ACROSS THE NEARSHORE WTRS WITH 15-20 KT ACROSS THE GA OFFSHORE WTRS AND BUILD SEAS 1-2 FT ABV WW3 GUIDANCE. WL ALSO DELAY THE ONSET OF VEERING WNDS FRI AS THE MODELS ARE TYPICALLY TOO QUICKLY IN BRINGING COASTAL TROFS ONSHORE. IT DOES APPEAR AS THOUGH AN EXTENDED PERIOD OF SCA CONDITIONS ARE LIKELY TO OCCUR OVR THE GA OFFSHORE WTRS AND MAY VERY WELL OCCUR OVR THE NEARSHORE WTRS. && .AVIATION /06Z-06Z/...WNDS HAVE PARTIALLY DECOUPLED AT BOTH TAF SITES BUT WNDS AROUND 1200 FT REMAIN NEAR 30 KT. WL NEED TO KEEP MENTION OF LLWS GOING THROUGH AT LEAST 14Z AFT WHICH SFC WNDS WL BEGIN TO INCR AS WNDS ALOFT SLOWLY DECR. VFR CONDITIONS WL PREVAIL FOR THE NXT 24 HRS. && .LAKE WINDS...THE LATEST OBSERVATIONS FROM PINEVILLE INDICATE SOLID LAKE WIND ADVISORY CONDITIONS ARE IN PROGRESS. THE LATEST RUC AND NAM OUTPUT SUGGESTS 975MB WNDS WL SURGE A BIT BTWN 09-12Z SO WL NEED TO EXTEND THE LAKE WIND ADVISORY THROUGH 8 AM...AFT WHICH A STEADY DECR IN SPEEDS WL OCCUR. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...LAKE WIND ADVISORY FOR LAKE MOULTRIE SCZ045 UNTIL 8 AM. MARINE...SMALL CRAFT ADVISORY FOR AMZ330-350-352-354-374. && $$ JRJ/ST ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 443 AM EST THU JAN 11 2007 .SHORT TERM... TODAY AND TONIGHT. PRIMARY FOCUS ON LOW LEVEL GULF MOISTURE TRANSPORT INTO SOUTHERN GREAT LAKES BY END OF SHORT TERM PERIOD. AT 09Z PLUME OF HIR SFC DPS FM ERN TX NOSING INTO ERN KS. WAVE EMBEDDED IN ML WSWRLY FLOW TO AID IN STRONG LEE SIDE CYCLOGENESIS TO FURTHER STRENGTHEN MOISTURE TRANSPORT TODAY. AS WAVE MOVES EWD INTO MS VALLEY TONIGHT AND STRONG SFC-8H FLOW VEERS MOISTURE AXIS TO SHIFT INTO CWA. WL SEE SFC DPS TO SHOW DRAMATIC RISE OF UP TO 20F HIR IN ABOUT 24HRS ADN CPDS LOWER TO NEAR ZERO AFTR 06Z. PRECIP TO BECOME MORE WIDESPREAD LATE TONIGHT IN INCREASINGLY CONFLUENT LOW LEVEL FLOW. HOWEVER...STRONGEST I295 PRES ADVECTION WILL BE EAST OF CWA WITH LOW LEVEL JET AFTER SUB CLOUD LAYER SATURATES...SO ANTICIPATE PRECIP TO BE MORE ON THE LIGHT SIDE WITH LESS FORCING...AND HAVE CUT QPF A BIT. WITH NAM AND GFS SHOWING GOOD OVERALL SIGNALS AND HIGH MOS POPS HOWEVER WILL UP POPS AFT MIDNIGHT TO LOW END CATAGORICAL. LITTLE CHANGE IN TEMPS TODAY. SHOULD SEE AT LEAST G35 MPH THIS AFTERNOON WHEN GREATEST 1000-950MB LAPSE RATES REALIZE BEST MOMENTUM XFER. SHOULD TEMPS TREND WARMER EVEN HIR GUSTS INTO LOW END ADVISORY RANGE COULD BE REALIZED. WITH CLOUD COVER/PRECIP AND WELL MIXED BL TONIGHT HAVE RAISED TEMPS A FEW DEGREES. && .LONG TERM... FRIDAY THROUGH WEDNESDAY PICTURE NOT A WHOLE LOT CLEARER FOR MUCH OF THE LONG TERM PERIOD THAN LAST NIGHT. RAIN IS EXPECTED TO CONTINUE INTO FRIDAY AS FIRST LOW MOVES ACROSS THE AREA WITH A COLD FRONT BEGINNING ITS SE MVMT ACROSS THE AREA SOMETIME FRI NGT OR SATURDAY. HAVE NOT INCREASED TO CAT POPS ANYWHERE ON FRI AS OF YET AS TRENDS HAVE BEGAN TO TAKE MUCH OF THE HIGHER PRECIP AMOUNTS AND COVERAGE TO THE SOUTH OF THE AREA. STILL APPEARS TO BE ENOUGH LIGHTER PRECIP AROUND TO MAINTAIN HIGH LIKELY POPS ALL AREAS ON FRIDAY AND EXTEND LIKELY POPS INTO FRI EVE IN SE AREAS. COLDER AIR WILL START TO FILTER IN LATE FRI NGT INTO SATURDAY. THIS AND AMOUNT OF REMAINING MSTR WILL LEAD TO A TRICKY SCENARIO IN TERMS OF PRECIP TYPE AND COVERAGE. NAM THERMAL FIELDS WOULD SUGGEST THAT ANY PRECIP WOULD REMAIN IN THE FORM OF RAIN...BUT WITH SFC TEMPS NEAR FREEZING COULD END UP FREEZING. THE GFS PROFILES SUGGEST MAINLY SNOW AS 850 MB TEMPS DROP TO AROUND -5 TO -7 C BY SAT AFTERNOON. THIS UNCERTANTITY HAS PLAGUED THE FORECAST FOR THE PAST FEW DAYS NOW AND APPEARS NO CLEARER NOW. MIX PRECIP WAS DROPPED A FEW DAYS AGO AND LOOK LIKE WILL BE FORCED TO THROW THIS BACK IN NW AREA LATE FRI NGT AND NW HALF OF SO ON SAT WITH JUST RAIN SE. FINAL SURGE OF WARMER AIR BEGINS SAT NGT INTO SUNDAY IN ADVANCE OF PESKY UPPER LOW OVER THE SW US BEGINNING TO EJECT AS ANOTHER WAVE AND 120+KT JET STREAK GIVE IT A KICK OUT. HOW MUCH MSTR AND WARM AIR ARRIVES FOR SUNDAY WILL BE KEY IN PCPN CHANCES AS WELL AS TYPE. THINK LIGHT PRECIP WILL ONCE AGAIN MATERIALIZE OVER MUCH OF THE CWA BY SUNDAY WITH HIGHEST CHC POPS REMAINING THERE. HOWEVER...DRIER AIR MASS AND SLOWER KICK OUT OF SYSTEM MAY PRECLUDE ARRIVAL OF PRECIP UNTIL LATE SUNDAY OR SUNDAY NIGHT. IT IS SUNDAY NIGHT AND MONDAY THAT MAY END UP THE MOST FAVORABLE PERIOD FOR SIGNIFICANT PRECIP WHICH COULD BE IN THE FORM OF SNOW OR ICE ESPECIALLY ACROSS NW HALF OF CWA. TRACK OF SFC LOW GENERALLY OVER OR SE OF THE CWA WITH MAIN CONSENSUS TRACKING ACROSS EASTERN OHIO ON MONDAY. ANY DEVIATION IN THIS WILL DRASTICALLY AFFECT THE ANTICIPATED LOCATION OF THE HEAVIEST PRECIP. PAST SEVERAL MODELS RUNS HAVE PLACED THE HEAVIEST SNOW FROM N ILLINOIS INTO PARTS OF CNTRL/NORTHERN LWR MI. HOWEVER...TRENDS STILL SUGGESTING THAT A BUFFER ZONE OF A MIXED BAG OF PRECIP COULD SET UP SOUTH OF THIS BAND WHICH WOULD INCLUDE PARTS OF THE CWA. MANY QUESTIONS REMAIN TO BE ANSWERED SO STAY TUNED TO LATER FORECASTS. BLAST OF ARCTIC AIR STILL ARRIVING BY MON NGT/TUES WITH TEMPS HEADING BELOW NORMAL FOR THE FIRST TIME IN SEVERAL WEEKS. ANY SNOW COVER COULD PLAY HAVOC WITH TEMPS AS WELL...ESPECIALLY AT NIGHT. WITH COLDER AIR OVER THE GREAT LAKES...LAKE EFFECT SNOW WILL LIKELY OCCUR BUT INTENSITY AND COVERAGE REMAIN TRICKY AS EITHER NW OR N FLOW COULD SET UP OVER LK MI NEXT WEEK. WILL LEAVE GRIDS ALONE FOR THIS TIME FRAME. && .AVIATION... VFR XPCD THROUGH THE PD. VIGOROUS LEAD SHORTWAVE IN SRN SK...WITH ASSOCD STRONG SFC LOW IN MN...SPLITTING AWAY FROM MAIN ENERGY IN NW WA. LLJ DEVELOPING ACROSS NRN IL AND WILL CONTINUE TO MOV EWD AS JET AXIS VEERS SLIGHTLY EARLLY THIS AM. SECOND GATE KIWX VWP TO 47 KTS IN SRN SK WITH STRONG SFC LOW IN MN...SECONDARY ENERGY/WAVE SPLITTING OFF INTO NW WA. THOUGH SOME MINOR SFC GUSTS POSBL THIS AM...CLEARLY SUFFICIENT DECOUPLING HAS OCCURRED ACRS NRN IN PER 05 UTC SFC ANALYSIS...WARRANTING CONTINUED MENTION OF LLWS AT BOTH SITES. HAVE FURTHER INCREASED WS020 WIND SPEED TO 60KTS AT KSBN PER KLOT VWP/WOLCOTT PROFILER/NAM12/RUC POINT SNDGS. GREATER MIXING BY MID/LATE MORNING AND BY AFTERNOON WIND GUST/MOMENTUM XFER POTENTIAL FOR AT LEAST G32 KTS. RAFL TO ARRIVE BEYOND 06 UTC AND WILL PROVIDE TIMING DETAILS WITH 12 UTC ISSUANCE...THOUGH AT LEAST MVFR BY 12 UTC FRI ANTICIPATED. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR LMZ043-LMZ046. && $$ SHORT TERM/AVIATION...MURPHY LONG TERM...FISHER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 105 AM EST THU JAN 11 2007 .AVIATION... VFR XPCD THROUGH THE PD. VIGOROUS LEAD SHORTWAVE IN SRN SK...WITH ASSOCD STRONG SFC LOW IN MN...SPLITTING AWAY FROM MAIN ENERGY IN NW WA. LLJ DEVELOPING ACROSS NRN IL AND WILL CONTINUE TO MOV EWD AS JET AXIS VEERS SLIGHTLY EARLLY THIS AM. SECOND GATE KIWX VWP TO 47 KTS IN SRN SK WITH STRONG SFC LOW IN MN...SECONDARY ENERGY/WAVE SPLITTING OFF INTO NW WA. THOUGH SOME MINOR SFC GUSTS POSBL THIS AM...CLEARLY SUFFICIENT DECOUPLING HAS OCCURRED ACRS NRN IN PER 05 UTC SFC ANALYSIS...WARRANTING CONTINUED MENTION OF LLWS AT BOTH SITES. HAVE FURTHER INCREASED WS020 WIND SPEED TO 60KTS AT KSBN PER KLOT VWP/WOLCOTT PROFILER/NAM12/RUC POINT SNDGS. GREATER MIXING BY MID/LATE MORNING AND BY AFTERNOON WIND GUST/MOMENTUM XFER POTENTIAL FOR AT LEAST G32 KTS. RAFL TO ARRIVE BEYOND 06 UTC AND WILL PROVIDE TIMING DETAILS WITH 12 UTC ISSUANCE...THOUGH AT LEAST MVFR BY 12 UTC FRI ANTICIPATED. && .SHORT TERM... TONIGHT AND AND THURSDAY... LATEST SFC ANALYSIS SHOWS RIDGE EXTENDING UP FROM TN/OH VALLEY INTO EASTERN GREAT LAKES. VIS SAT SHOWING BAND OF MID-LEVEL CLOUDS AHEAD OF WARM FRONT ON BACK SIDE OF SFC HIGH MOVING THROUGH THE AREA ATTM. BACK EDGE OF CLOUDS PUSHING THROUGH WESTERN ILLINOIS AND EXPECTING CLEARING IN OUR AREA LATER THIS EVENING AS WARM FRONT LIFTS QUICKLY NORTHWARD. SFC HIGH SLIDES EAST BRINGING STRONGER GRADIENT OVER THE AREA TONIGHT. DESPITE SOME POSSIBLE DECOUPLING EARLY ON...ESPECIALLY IN EASTERN CWA...NOT LOOKING FOR MUCH IN THE WAY OF DIURNAL COOLING AS CLOUD COVER EARLY EVENING AND WAA AFTER MIDNIGHT SHOULD WORK TO LIMIT RADIATIONAL COOLING TONIGHT AND KEEP TEMPS NEAR GUIDANCE. LOOK FOR A DECENT AMOUNT OF SUNSHINE EARLY ON TOMORROW BEFORE CLOUDS ARE ON THE INCREASE ONCE AGAIN BY AFTERNOON. MORNING SUN SHOULD SET THE STAGE FOR GUSTY WINDS WITH 15-20KT SUSTAINED AND MIXING DOWN GUSTS TO 30KT. GOOD WAA WILL SEE NEARLY A 10C JUMP IN 850MB TEMPS FROM NOW TO THURSDAY AFTERNOON. UPSTREAM TEMPS THAT WERE NOT AFFECTED BY MID CLOUDS GENERALLY IN THE MID-UPPER 40S WITH SOME 50S FURTHER BACK IN W/SW MO SO WILL BLEND MET/MAV GUIDANCE AND GO AROUND 45 NE AND NEAR 50 SW. && .LONG TERM... SIMILAR SCENARIO BETWEEN THE GFS AND NAM-WRF FOR TOMORROW NIGHT...BUT A DIFFERENCE LIES WITHIN THE RAIN CHANCES BETWEEN THE TWO. GFS OF COURSE IS SHOWING HIGHER CHANCE/MUCH MORE QPF THAN THE NAM-WRF IS...BUT WITH HIGH GUIDANCE POPS FOR TOMORROW NIGHT...ESPECIALLY AFTER MIDNIGHT...AND PAST FEW MODEL RUNS SHOWING THE SURFACE TROUGH IN THE AREA...HAVE INCREASED RAIN CHANCES FOR TOMORROW NIGHT. BY 12Z FRIDAY THE SURFACE TROUGH WILL BE JUST TO THE WEST OF OUR CWA. THIS TROUGH IS THEN PROGGED TO MOVE INTO THE CWA ON FRIDAY...RAIN CHANCES FOR THIS TIME MAY LIKELY HAVE TO BE INCREASED BUT KEPT LIKELY CHANCES FOR THE TIME BEING. THEN FRIDAY NIGHT THE TROUGH BEGINS TO MOVE EAST OF THE CWA...DECREASING THE RAIN CHANCES. ANY PRECIP ON SATURDAY COULD TAKE ON A DIFFERENT FORM...BUT THIS FAR OUT DID NOT WANT TO TRY AND GET CUTE WITH PRECIP TYPES AND WHERE AT. MODEL SOUNDINGS ARE SHOWING THE SATURDAY TIME FRAME TO BE AROUND THE FREEZING MARK...SOME EVEN LATE FRIDAY NIGHT...KEEPING WHAT FORM THE PRECIP WILL TAKE TRICKY. THEREFORE WILL NOT CHANGE THE TYPE OF PRECIP FOR SATURDAY THROUGH SATURDAY NIGHT THAT IS IN THE FORECAST BUT DID MODIFY POPS A LITTLE TO SHOW A LESSER PRECIP CHANCE FOR SATURDAY AND SATURDAY NIGHT THAN FRIDAY NIGHT AND SUNDAY. THEN THERE HAVE BEEN SOME MODEL TIMING CHANGES/DIFFERENCES FOR THE LOW TO EJECT OUT OF THE SOUTH CENTRAL UNITED STATES FOR NEXT WEEK. SO NO CHANGES FOR NEXT WEEK...BUT IS LOOKING LIKE SUNDAY HAS A GOOD CHANCE TO BE WET WITH A WEAK LOW MOVING NORTHEASTWARD UP THE SURFACE TROUGH TO OUR SOUTHEAST...THEN ANOTHER LOW TO SOUTHEASTERN MISSOURI/SOUTHERN ILLINOIS BY SUNDAY EVENING. BY MONDAY MORNING THE LOW IS CURRENTLY PROGGED TO BE OVER NORTHWESTERN OHIO AND THEN ON TO THE NORTHEAST DURING MONDAY. DID NOT CHANGE THE PRECIP TYPE FOR SUNDAY NIGHT YET EVEN THOUGH ITS LOOKING LIKE THE REAL COLD AIR PUSH INTO THE CWA WILL NOT BE UNTIL THE DAYTIME MONDAY...NOT LOOKING COLD ENOUGH IN THE TEMPERATURE PROFILE FOR ALL SNOW UNTIL MONDAY. THEN DECENT FETCH DOWN LAKE MICHIGAN MONDAY NIGHT FOR LAKE EFFECT SNOW TO TAKE SHAPE. THE LAKE EFFECT SNOW CHANCES THEN LOOK LIKE THEY COULD CONTINUE THROUGH TUESDAY NIGHT. THEN WITH THE HIGH PRESSURE MOVING IN ON WEDNESDAY AND CHANGING THE WIND DIRECTION TO THE SOUTHWEST...THE LAKE EFFECT SNOW WILL END. BUT LIKE MENTIONED ABOVE...THERE HAVE BEEN TIMING CHANGES IN THE MODELS FOR NEXT WEEK SO MADE NO CHANGES FOR THEN FOR NOW. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY THROUGH 7 PM EST THURSDAY FOR LMZ043-LMZ046. && $$ AVIATION...MURPHY SHORT TERM...LOGSDON LONG TERM....LOTHAMER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 900 PM CST THU JAN 11 2007 .DISCUSSION... CONUNDRUM THIS EVE CENTERS AROUND FRZG DRZL POTENTIAL AND FATE OF CURRENT ADVY. LG WV TROUGH SETTLING INTO WRN CONUS WITH BROAD SWLY FLOW AHEAD INTO PLAINS. 120+KT JET SEGMENT NOTED FROM KS INTO UPPER OH RIVER VALLEY WITH LARGE PCPN SHIELD ON LEADING EDGE. SHRT WV WITH THIS FEATURE ADVANCING THROUGH MID/UPR MS VALLEY INTO GREAT LAKES PUSHING DEEPER MOISTURE OFF TO THE E. LITTLE DEEP UVM OR QG FORCING NOTED OVER IA...ALTHOUGH THERE IS SOME TO OUR N AS SHRT WV EJECTS OUT OF NRN PORTION OF TROUGH. SOME H85/H7 FN CONVERGENCE BUT MOISTURE NOT SUFFICIENT FOR RESPONSE. LGT RAIN/DRZL THAT APPEARS TO BE DIMINISHING IN RADAR TRENDS LOOKS TO BE DRIVEN BY THETA-E ADVECTION AND UVM IN SATURATED H9/H8 LAYER. 02Z SFC ANLYS PLACES CDFNT ACROSS SERN IA WITH SVRL EMBEDDED WVS. CANNOT REALLY PICK OUT A PRIMARY ONE...BUT LATEST RUC PUSHES ALL THESE LOW LEVEL MECHANISMS OFF TO THE EAST WITH 925MB TROUGH BY 06Z. HOWEVER RUC ALSO LINGERS THIS SATURATED LAYER ALONG AND S OF I80 THROUGH 06Z AND LINES UP WITH ECHOES TO OUR W. OAX REPORTS FLURRIES/FRZG DRZL HAVING MINIMAL EFFECT EVEN IN COLDER AIR THUS WILL KEEP MENTION OF PATCHY FRZG DRZL OR FLURRIES GOING WHERE APPROPRIATE AS IT MOVES FROM W TO E...BUT DROP HEADLINE. DO NOT EXPECT CONDITIONS THAT WOULD BE IMPLIED BY FRZG RAIN ADVY AND FRZG DRZL ADVY IS NO LONGER A VALID HEADLINE. BETTER LIKELIHOOD MAY EVEN BE FARTHER N INTO COLDER AIR OUTSIDE OF CURRENT HEADLINE...BUT NOT SUBSTANTIAL ENOUGH TO WARRANT NEW ONE. WET ROADS MAY START FREEZING FROM EXISTING MOISTURE TOO AS COLD ADVECTION CONTINUES. IEM FREEZE APP HAS SUB-FRZG ROAD TEMPS ALG AND NW OF ADAIR-BOONE-IOWA FALLS LINE AND SLOWLY ADVANCING SE. WILL HIT HARD IN NOWCASTS THAT SLICK SPOTS MAY DEVELOP...BUT LIKELY NOT AGGRAVATED MUCH BY ADDITIONAL MOISTURE. ALSO DROPPED HOURLY TEMP/DEWPOINTS TO SUPPORT MORE AGGRESSIVE COLD/DRY ADVECTION. 02Z SFC ANLYS ALSO SHOWED WIDESPREAD SIGNIFICANT PRES RISES BEHIND CFP. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 1113 AM EST WED JAN 10 2007 .SYNOPSIS... A COLD FRONT ASSOCIATED WITH A STRONG UPPER LEVEL DISTURBANCE WILL CROSS THE REGION WITH SNOW SHOWERS AND FLURRIES THROUGH THIS EVENING. HIGH PRESSURE WILL BUILD ACROSS THE REGION LATER TONIGHT AND THURSDAY. CLOUDS WILL BE ON THE INCREASE AS A WARM FRONT APPROACHES THURSDAY AFTERNOON AND THURSDAY NIGHT. A STRONG COLD FRONT WILL MOVE SOUTH FROM QUEBEC PROVINCE AND CROSS THE REGION LATE FRIDAY NIGHT AND EARLY SATURDAY. && .UPDATE... BAND OF SNOW SHOWERS AND SNOW SQUALLS HAS NOW DRIFTED INTO EAST CENTRAL AREAS IE SRN ZNS 2 AND ZNS 5/6... HAVE ISSUED A QUICK UPDATE TO ADJUST POPS/WX TO BETTER FIT CURRENT TRENDS. XPCT THIS ACTIVITY TO CONT TO DRIFT SEWRD THRU THE AFTN W/ WEAKENING BY ERLY EVE... && .PREV DISCUSSION... SYNOPSIS... A COLD FRONT ASSOCIATED WITH A STRONG UPPER LEVEL DISTURBANCE WILL CROSS THE REGION WITH SNOW SHOWERS AND FLURRIES THROUGH THIS EVENING. HIGH PRESSURE WILL BUILD ACROSS THE REGION LATER TONIGHT AND THURSDAY. CLOUDS WILL BE ON THE INCREASE AS A WARM FRONT APPROACHES THURSDAY AFTERNOON AND THURSDAY NIGHT. A STRONG COLD FRONT WILL MOVE SOUTH FROM QUEBEC PROVINCE AND CROSS THE REGION LATE FRIDAY NIGHT AND EARLY SATURDAY. SHORT TERM /TODAY THROUGH THURSDAY/... FORECAST CHALLENGE WILL BE THE COVERAGE OF SNOW SHOWERS ASSOCIATED WITH THE UPPER TROUGH PASSAGE TODAY. SAT IMG THIS MORNING INDICATES UPPER TROUGH CENTERED JUST SOUTH OF JAMES BAY WITH DEVELOPING LOW PRESSURE WELL SOUTH OF THE GULF OF MAINE. MODELS CONSISTENT WITH UPPER TROUGH CROSSING THE STATE THIS AFTERNOON AND THEN MOVING EAST OF THE REGION EARLY THIS EVENING. AS UPPER TROUGH MOVES ACROSS THE AREA...ASSOCIATED COLD FRONT/SURFACE TROUGH WILL ALSO CROSS THE STATE. THE PROBLEM IS MOS GUIDANCE INDICATING MINIMAL POPS TODAY WITH ALL THE ENERGY TO BE TRANSFERED TO SURFACE LOW PRESSURE WELL SOUTH OF THE GULF OF MAINE. THIS APPEARS TO BE ALREADY HAPPENING AS INDICATED BY CLOUD TOPS COOLING THIS MORNING WITH THE LOW PRESSURE. HOWEVER...SNOW SHOWERS ALREADY BREAKING OUT OVER QUEBEC WITH UPPER TROUGH AS OBS IN QUEBEC INDICATING SNOW SHOWERS REDUCING VSBY TO 1 NM IN PLACES. PAST EXPERIENCE WITH THESE TYPES OF SYSTEMS IS GUIDANCE USUALLY UNDERESTIMATES THE POP AND QPF SO WILL GO ABOVE GUIDANCE FOR TODAY. LATEST RUC ALSO INDICATING VORT MAX TO MOVE ACROSS NORTHERN SECTIONS THIS AFTERNOON SO WILL UP POPS TO LIKELY OVER NORTHERN SECTIONS AND ALONG UPSLOPE REGIONS OF NORTHWEST MAINE. WITH LIMITED MOISTURE WILL ONLY BE ABLE TO SQUEEZE OUT NO MORE THAN A TENTH OF AN INCH OF QPF SO WILL KEEP SNOWFALL AMOUNTS AN INCH OR LESS. UPPER TROUGH MOVES EAST OF THE REGION THIS EVENING WITH CLEARING SKIES BY MIDNIGHT. A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE STATE ON THURSDAY. SKIES START OUT CLEAR THURSDAY MORNING BUT AS HIGH PRESSURE MOVES EAST...WARM AIR ADVECTION ALOFT WILL ALLOW HIGH CLOUDS TO MOVE INTO THE STATE FROM THE WEST DURING THE AFTERNOON. LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HAVE FOLLOWED THE GFS SOLUTION WHICH IS SUPPORTED BY THE LATEST RUN OF THE ECMWF/CANADIAN GLOBAL MODELS WHICH CONTINUES TO INCREASE CLOUDS IN BROAD SOUTHWEST WAA PATTERN AROUND DEPARTING SURFACE RIDGE AND AHEAD OF STRONG COLD FRONT APPROACHING FRONT FROM QUEBEC THURSDAY NIGHT INTO FRIDAY. WITH WEAK LIFT NOTED EMBEDDED WITHIN THE UPPER FLOW WILL EXPAND MENTION OF SNOW SHOWERS ESPECIALLY FOR THE NORTH AND MOUNTAINS THURSDAY NIGHT. ALL MODELS FAVOR A LONG TRAJECTORY OF MOISTURE TRANSPORT WITHIN THE SOUTHWEST FLOW FROM THE OHIO VALLEY AND GREAT LAKES AHEAD OF AN APPROACHING ARCTIC BOUNDARY DURING FRIDAY. HAVE ADJUSTED AND INCREASES POPS AS FRONTAL CONVERGENCE INCREASES ACROSS THE CWA DURING FRIDAY AND FRIDAY NIGHT. ARCTIC HIGH PRESSURE PRESSES THE FRONTAL BOUNDARY WELL TO THE SOUTH OF THE CWA DURING SATURDAY. THIS HELPS ESTABLISH A GRADUAL CLEARING TREND FROM NORTH TO SOUTH DURING SATURDAY INTO SATURDAY NIGHT. NEXT POTENTIAL BOUT OF WINTER WEATHER FOR THE CWA COMES IN RESPONSE TO ENERGY LIFTING OUT OF THE CENTRAL PLAINS AND INTO THE NORTHEAST INITIATING CYCLOGENESIS ALONG THE ARCTIC FRONTAL BOUNDARY DURING THE LATTER HALF OF THE WEEKEND. MODELS ARE TRENDING WITH MORE OF A CONSENSUS TO TAKE THE SURFACE LOW ACROSS OR JUST SOUTH OF THE CWA WHICH WOULD RESULT IN SNOW ACROSS THE NORTH AND AND AT LEAST MIXED PRECIPITATION DOWNEAST LATE SUNDAY INTO MONDAY. AVIATION /08Z-06Z/... GENERALLY VFR CONDITIONS THROUGH NOONTIME. MVFR CIGS AND VSBY ARE THEN POSSIBLE IN HEAVIER SNOW SHOWERS MAINLY OVER NORTHERN AREAS THIS AFTERNOON. SKIES CLEAR TONIGHT AS UPPER TROUGH MOVES EAST OF THE REGION. MARINE... SHORT TERM: WINDS HAVE DROPPED BELOW SCA CRITERIA THIS MORNING BUT SEAS REMAIN ABOVE 5 FT DUE TO SOUTHWEST SWELL. SEAS WILL REMAIN ABOVE SCA FOR MOST OF TODAY AND THEN WINDS WILL INCREASE LATE TODAY AS FRESH SURGE OF COLD AIR MOVES ACROSS THE WATERS. SINCE WINDS ARE EXPECTED TO GO ABOVE SCA CRITERIA THIS EVENING WILL CONTINUE SCA. SCA CONDITIONS WILL CONTINUE INTO THURSDAY MORNING AND THEN DROP BELOW SCA LEVELS IN THE AFTERNOON AS HIGH PRESSURE BUILDS ACROSS THE REGION. LONG TERM: TIGHT PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE CENTERED OFF THE MID ATLANTIC COAST AND A COLD FRONT MOVING SOUTH FROM QUEBEC PROVINCE WILL INCREASE SOUTHWEST WINDS TO STRONG SCA CONDITIONS LATE THURSDAY NIGHT AND EARLY FRIDAY. AFTER A BRIEF DECREASE IN WINDS...INCREASING CAA MAY RETURN CONDITIONS TO SCA LEVELS SATURDAY AFTERNOON INTO SATURDAY EVENING. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 12 PM EST THURSDAY FOR ANZ050. && $$ SHORT TERM UPDATE/MARINE...KHW me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 412 PM EST THU JAN 11 2007 .SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING EXTENDING FROM HUDSON BAY TO NORTHERN CALIFORNIA AND RIDGING OVER THE SOUTHEAST U.S.. THERE ARE A FEW WEAK SHRTWVS MOVING THROUGH THE SW FLOW BETWEEN THE TROUGH AND RIDGE...BUT DUE TO THE PRESENCE OF DRY AIR IN THE MID-LEVELS AS SEEN ON 12Z SOUNDING...NOT MUCH IS OCCURRING WITH THEM. ONE OF THE SHRTWVS IS MOVING THROUGH EASTERN NEBRASKA...AND WHEN COMBINED WITH SOME UPPER DIVERGENCE IN THE RIGHT REAR QUADRANT OF A 130KT JET MAX MOVING THROUGH NORTHERN ONTARIO AND 800-600MB FRONTOGENESIS...HAS HELPED TO PRODUCE BANDS OF LIGHT TO MODERATE REFLECTIVITIES IN MINNESOTA. HOWEVER...AGAIN WITH THE PRESENCE OF DRY AIR...VERY FEW LOCATIONS ARE REPORTING SNOWFALL. CLOSER TO HOME...TEMPERATURES ARE AGAIN ABOVE NORMAL AHEAD OF A COLD FRONT. THIS COLD FRONT EXTENDS FROM A 1009 MB LOW IN NORTHERN LAKE SUPERIOR...ACROSS THE WESTERN U.P. AND INTO THE TEXAS PANHANDLE. BEHIND THE COLD FRONT...NORTHWEST WINDS CONTINUE TO ADVECT IN COLD AIR FROM THE PLAINS. RIGHT NOW READINGS ARE IN THE SINGLE DIGITS BELOW ZERO F OVER NORTH DAKOTA AND EVEN NEAR 20 BELOW F OVER CENTRAL MANITOBA. THE ACTUAL SURFACE HIGH ASSOCIATED WITH THE COLD READINGS IS LOCATED IN CENTRAL SASKATCHEWAN (PRESSURE NEAR 1040MB). && .DISCUSSION... SHRTWV OVER EASTERN NEBRASKA IS PROGGED TO MOVE ACROSS THE CWA LATER TONIGHT...ALLOWING THE COLD FRONT TO BEGIN MAKING MORE OF A PUSH EASTWARD. THIS SHRTWV...COMBINED WITH THE UPPER DIVERGENCE AND FRONTOGENESIS MENTIONED EARLIER...MAY SUPPORT SOME LIGHT SNOW OVER THE CWA TONIGHT. HOWEVER...WITH THE DRY AIR IN THE MID LEVELS... ACTUAL PCPN AMOUNTS SHOULD REMAIN SMALL. WAS NEARLY TEMPTED TO MENTION SOME FREEZING DRIZZLE DUE TO THE LOW LEVELS MOISTENING UP BEHIND THE COLD FRONT...BUT THE SEEDER-FEEDER PROCESS LOOKS TO OCCUR AT THE TIME THE LOW LEVELS MOISTEN...SO KEPT THE FREEZING DRIZZLE MENTION OUT. ALSO...AS THE COLD FRONT PASSES...THE COLDER AIR SEEN OVER NORTHERN MINNESOTA AND THE PLAINS WILL ADVECT INTO THE CWA...ALLOWING FOR SOME LES TO START UP. LOW INVERSION HEIGHTS AND LACK OF CONVERGENCE WILL KEEP THE SNOW LIGHT. THEREFORE SNOW ACCUMULATION AMOUNTS FOR ALL OF TONIGHT SHOULD ONLY BE AN INCH OR LESS. HAVE RAISED TEMPERATURES IN THE EASTERN CWA AS IT LOOKS LIKE THE COLD AIR WILL TAKE THE LONGEST TO GET THERE...AND ALSO MATCHES BETTER WITH MAV/MET GUIDANCE. COLDEST TEMPERATURES EXPECTED OUT WEST WHERE COLDER AIR MAKES IT IN FIRST. ON FRI...THE UPPER TROUGH IS PROGGED TO SPLIT IN TWO AS A RESULT OF A POLAR LOW DROPPING S THROUGH THE NUNAVUT REGION WHICH INDUCES RIDGING OVER SOUTH CENTRAL CANADA. THIS MOTION ALLOWS FOR THE HIGH PRESSURE AREA OVER SASKATCHEWAN TO DROP DOWN INTO THE DAKOTAS. NORTHERLY FLOW ON THE EAST SIDE OF THE HIGH WILL CONTINUE TO DRAG COLDER AIR INTO UPPER MICHIGAN...AS NOTED TOO BY 850MB TEMPS ON THE GFS/NAM FALLING TO -16 TO -20C BY 00Z SAT. THEREFORE MOST IF NOT ALL LOCATIONS SHOULD SEE THEIR HIGHS IN THE MORNING...WITH READINGS FALLING THROUGH THE DAY. THIS COLD ADVECTION IS ALSO ASSOCIATED WITH DRY AIR...ESPECIALLY GIVEN THAT RIGHT NOW PICKLE LAKE ONTARIOS DEWPOINT IS -17F. SO ALTHOUGH LAKE EFFECT SNOW SHOWERS ARE EXPECTED DUE TO THE COLD AIR...THAT DRY AIR AND CONTINUED LOW INVERSION HEIGHTS SHOULD KEEP SNOWFALL AMOUNTS AT AN INCH OR LESS...ESPECIALLY WITH NO CONVERGENCE AREAS ANTICIPATED. FOR FRI NIGHT INTO SAT...GFS/UKMET/ECMWF ALL SHOW THE UPPER LOW OVER THE NUNAVUT AREA DROPPING INTO HUDSON BAY...MAINTAINING A WESTERLY FLOW ALOFT AT 500MB OVER UPPER MICHIGAN. THE RESULT OF THE LOW DROPPING SOUTHWARD IS TO CAUSE THE HIGH PRESSURE AREA OVER THE DAKOTAS TO EXPAND EASTWARD. IN FACT...BY 18Z SAT...THE MODELS SUGGEST THAT THE AREA WILL DROP S OF THE AREA. THEREFORE...LIGHT LAKE EFFECT SNOW SHOWERS THAT ARE OCCURRING OVER THE NORTHERN U.P. WILL CONTINUE INTO SAT MORNING...BEFORE THE WINDS TURN WSW AND PUSH MUCH OF THE LAKE EFFECT OFFSHORE. IT APPEARS THAT WITH THE WINDS LIGHTENING DUE TO THE HIGH PRESSURE RIDGE BUILDING IN FRI NIGHT... LAND BREEZES ARE EXPECTED TO BECOME MORE OF AN INFLUENCE... ALLOWING FOR SOME AREAS OF CONVERGENCE TO DEVELOP. HOWEVER... SOUNDINGS CONTINUE TO SHOW LOW INVERSION HEIGHTS (UNDER 5000FT) AND PLENTY OF DRY AIR...SO EVEN CONVERGENT BANDS SHOULD NOT PRODUCE MUCH SNOW. TEMPERATURES WILL BE RELATIVELY COOL FRI NIGHT... ESPECIALLY GIVEN THE COLD AIR THAT ENTERED THE CWA ON FRI. HOWEVER...THESE READINGS ARE AROUND NORMAL. IF MORE CLEARING OCCURS...ESPECIALLY IN THE INTERIOR...SOME BELOW ZERO READINGS ARE LIKELY. RETURN FLOW SETTING UP ON SAT SHOULD ALLOW TEMPERATURES TO REBOUND A BIT...BACK UP INTO THE UPPER TEENS/LOW 20S. IN FACT...THE GFS SHOWS 850MB TEMPS WARMING TO AROUND -12C BY 00Z SUN. SAT NIGHT INTO SUN...UPPER LOW OVER HUDSON BAY IS PROGGED TO MOVE INTO NW QUEBEC SUN MORNING AND THEN INTO NEWFOUNDLAND BY 00Z MON. A COLD FRONT ASSOCIATED WITH THIS UPPER LOW IS EXPECTED TO MOVE INTO THE CWA SUN MORNING...FOLLOWED BY ANOTHER CANADIAN HIGH PRESSURE AREA WHICH BUILDS INTO THE DAKOTAS LATE SUN. DRY AIR AHEAD OF THE FRONT SHOULD KEEP IT PRECIPITATION FREE. HOWEVER...ANOTHER SURGE OF COLD AIR BEHIND THE FRONT WILL RESULT IN MORE LAKE EFFECT SNOW. AGAIN...THE AIR SINCE IT IS OF ARCTIC ORIGIN WILL NOT HAVE MUCH MOISTURE WITH IT...KEEPING THE LAKE EFFECT LIGHT. ALTHOUGH COOLER AIR IS HEADING INTO THE CWA...850MB TEMPS FALLING TO NEAR -19C BY 00Z MON PER THE GFS...SURFACE TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL DUE TO NORTHERLY FLOW BRINGING LAKE SUPERIOR MODIFIED AIR INTO THE CWA. EXTENDED (MON THROUGH THU)...OPERATIONAL MODELS ARE IN OVERALL GOOD AGREEMENT DURING THIS TIME PERIOD...SUGGESTING IN THE MEAN TROUGHING TO REMAIN OVER THE GREAT LAKES AND RIDGING IN WESTERN NORTH AMERICA...A TYPICAL WINTER TIME PATTERN. AS THE SYSTEM IN THE OHIO VALLEY MOVES OFF TO THE NE SUN NIGHT...NORTHERLY FLOW BEHIND IT WILL CONTINUE TO DRAG COLDER BUT DRY AIR SOUTHWARD ACROSS LAKE SUPERIOR. BY 00Z TUE...THE ECMWF SHOWS 850MB TEMPS FALLING ABOUT 6C FROM 00Z MON TO -19C. THEREFORE EXPECT SOME LAKE EFFECT SNOW TO OCCUR...BUT NOTHING TOO HEAVY DUE TO THE DRY AIR AND LOW INVERSION HEIGHTS AS SEEN ON GFS SOUNDINGS. THIS POOL OF COLD AIR WILL BEGIN TO HEAD OFF TO THE E ON TUE AS A PORTION OF THE WESTERN NORTH AMERICA RIDGE IS PUSHED INTO CENTRAL CANADA. LAKE EFFECT WILL PROBABLY PERSIST INTO TUE...BUT WITH A SURFACE RIDGE MOVING IN RESULTING IN EVEN DRIER AIR AND LOWER INVERSIONS... NOT EXPECTING A LOT OF SNOWFALL. ON WED...THE RIDGE AXIS OVER CENTRAL CANADA WILL MOVE SE OVER UPPER MICHIGAN AS A RESULT OF A CLIPPER SYSTEM MOVING DOWN FROM THE NORTHWEST TERRITORIES. THE 06Z GFS/00Z ECMWF BOTH DEPICT THIS CLIPPER TO BE LOCATED OVER NW ONTARIO. BOTH MODELS DEPICT THE BETTER LIFT STAYING NORTH OF LAKE SUPERIOR...AND WITH A DRY AIRMASS ALREADY IN PLACE FROM TUE...PREFER NOT TO INSERT ANY POPS FOR THE CLIPPER. HOWEVER...WSW WARM AIR ADVECTION AHEAD OF THE CLIPPER WILL RESULT IN A BREEZY DAY. BY 00Z THU...THE ECMWF SHOWS 850MB TEMPS CLIMBING UP TO 10C...SO LAKE EFFECT WILL LIKELY NOT SHUT OFF BUT JUST RE-ALIGN TO THE WIND DIRECTION. FOR WED NIGHT INTO THU...A TROUGH ASSOCIATED WITH THE CLIPPER ALONG WITH AN UPPER LEVEL SHRTWV ARE PROGGED TO MOVE ACROSS THE CWA...SO KEPT SOME LOW CHANCE POPS IN FOR THOSE. OVERALL THOUGH...THROUGHOUT THE EXTENDED...IT DOES NOT APPEAR THAT MUCH PRECIPITATION IS GOING TO OCCUR. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1125 AM EST THU JAN 11 2007 .UPDATE... WATER VAPOR IMAGERY SHOWS A SHORTWAVE TRACKING THRU ONTARIO. AT THE SFC...ASSOCIATED BROAD SFC LOW APPEARS TO BE CENTERED OVER FAR NRN LAKE SUPERIOR. TROFFINESS HANGS BACK ACROSS NRN MN WITH ARCTIC AIR JUST TO THE N IN ONTARIO AND MANITOBA. FARTHER W...ARCTIC AIR IS SURGING S ACROSS THE DAKOTAS. UPPER DIVERGENCE IN RIGHT ENTRANCE OF JET ASSOCIATED WITH ONTARIO SHORTWAVE IS LEADING TO RADAR RETURNS IN NE MN...BUT HAVE NOT SEEN ANY SFC OBS INDICATING PCPN. LOW-LEVEL JET HAS SHIFTED E OF FCST AREA...AND WITH BAGGY PRES GRADIENT DEVELOPING...WINDS ARE DIMINISHING FROM W TO E THIS MORNING. GOING FCST IS IN GOOD SHAPE FOR THE AFTN AND REQUIRES LITTLE IF ANY CHANGE. AS UPPER JET TRANSLATES E THIS AFTN...UPPER DIVERGENCE WILL ALSO SHIFT E. GIVEN THE RADAR RETURNS IN NE MN...IT IS NOT OUT OF THE QUESTION THAT A FEW -SHSN MAY DEVELOP OVER THE FAR W TOWARD EVENING. OTHERWISE...EXPECT A DRY AFTN. CLOUDS SHOULD GENERALLY HOLD TOUGH THRU THE AFTN...BUT VIS SATELLITE IMAGERY INDICATES CLOUDS ARE FAIRLY THIN ACROSS NRN WI INTO SRN UPPER MI. THIS MAY ALLOW TEMPS TO GET A COUPLE OF DEGREES HIGHER THAN 36-38F IN THE GOING FCST. && .PREV DISCUSSION... ISSUED AT 330 AM EST 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WSW FLOW ALF BTWN DEEPENING TROF OVER THE PAC NW (12Z-24Z H3 HGT FALLS UP TO 200M THERE WITH SHRTWV DIGGING ALG THE PAC NW COAST) AND UPR RDG AXIS MOVING INTO SE ONTARIO. STRONG SHRTWV EMBEDDED WITHIN THIS FLOW IS MOVING INTO SRN MANITOBA...WITH ONLY WEAK SFC LO OVER ERN ND JUST NW OF FAR. STRONG ISENTROPIC ASCENT NOTED IN ADVANCE OF THIS SHRTWV... AND MQT VWP SHOWS S WINDS UP TO 55KT AT 3K FT MSL. GALE FORCE WINDS OBSVD OVER LK SUP FM ISLE ROYALE TO STANNARD ROCK. STRONG WAD HAS CONTRIBUTED TO EXTENSIVE MID CLD DECK OVER THE UPR GRT LKS...BUT DRY AIR SHOWN ON THE 00Z GRB RAOBS/ TAMDAR SDNG FM SAW BTWN H9-775 OR SO HAS RESTRICTED SN FOR THE MOST PART TO THE COLD SIDE OF H85 WARM FNT...LOCATED AT 00Z FM CKC-CMX-ERY...WHERE 0Z GFS F6 ALSO SHOWS SOME UPR DVGC. LTL IF ANY PCPN NOTED CLOSER TO THE SFC LO AND ALG ATTENDANT LO PRES TROF STRETCHING TO THE SW AS 00Z BIS/ABR/MPX SDNGS EXCESSIVELY DRY. MUCH COLDER AIR OBSVD OVER MT/ADJOINING AREAS IN SRN CAN. MAIN FCST CONCERNS THIS PACKAGE ARE PCPN CHCS ASSOCIATED WITH SHRTWV/SFC LO TO THE WNW TDAY AND THEN DISTURBANCES IN WSW FLOW ALF IN THE WAKE OF THIS SHRTWV LATER AS VERY COLD AIR TO THE NW POISED TO MOVE INTO THE UPR GRT LKS. FOR TDAY...NAM/GFS/UKMET SHOW SFC LO OVER NE MN THIS MRNG MOVING ACRS NRN LK SUP INTO SE ONTARIO BY 00Z AS SHRTV NR LK WINNIPEG SHEARS ENE ACRS ONTARIO...WITH ATTENDANT LO PRES TROF DRIFTING INTO THE CNTRL ZNS BY 00Z FRI. GIVEN EXCESSIVELY DRY AIRMASS UPSTREAM AT BIS/MPX/ ABR...PREFER THE DRIER NAM FCST (ZERO QPF) AS SHARPER ISENTROPIC LIFT/H85-5 QVECTOR CNVGC/LINGERING UPR DVGC/DEEPER MSTR EXIT EARLY THIS MRNG AND GIVE WAY TO DRYING ALF/H85-5 QVECTOR DVGC BY 18Z. IN FACT...GFS FCST SDNGS DEPICT THIS MID LVL DRYING QUITE WELL ABV INCREASINGLY SHALLOW MOIST LYR. TDAY WL BE WARMEST DAY OF NEXT WEEK AT LEAST AS SW FLOW IN ADVANCE OF APRCHG LO PRES TROF ADVECTS WARMER AIR FM THE SW...WHERE HI TEMPS REACHED NR 40 OR SRN MN ON WED...INTO THE FA. GFS/UKMET/NAM SHOW A STRIPE OF HIER MID LVL RH DVLPG OVER THE NRN PLAINS THIS AFTN AND STREAKING ENE INTO THE WRN CWA LATE TDAY/TNGT/ FRI AS WAVES OF UPR DVGC IN RRQ OF H3 JET MAXES/SHRTWVS SHEARING ENEWD THRU WSW FLOW ALF IN CONFLUENCE ZN BTWN NRN/SRN BRANCHES AS WELL AS ACCOMPANYING H8-7 FGEN OVER RELATIVELY SHALLOW COLD AIR TO THE NW OF ARCTIC BNDRY NOW SEPARATING VERY COLD AIR IN MT/SRN CAN FM WARMER AIR STILL IN THE NRN PLAINS/MN THAT IS FCST TO GRDLY OOZE SE ACRS THE UPR LKS. THINK TRYING TO TIME EACH OF THESE WAVES WL BE FRUITLESS ATTM...SO WL CARRY CHC POPS ACRS MOST OF THE AREA THRU FRI TO ACCOUNT FOR THIS FGEN FORCING/POTENTIAL LES AS COLDER AIR GRDLY OVERSPRDS THE FA. IN GENERAL...WL GO WITH HIER CHC POPS TO THE NW EARLY IN THE PD AND GRDLY SHIFT THE HIER POPS TO THE SE AS ARCTIC BNDRY DRIFTS SLOWLY SE WITH TIME. RELATIVELY SHALLOW DEPTH OF COLD AIR AS WELL AS NEUTRAL-ALMOST ACYC LARGER SCALE LLVL FLOW WOULD SUG ANY LES WL BE ON THE LGT SIDE DESPITE ARRIVAL OF MUCH COLDER AIR BLO SHALLOW INVRN (GFS/NAM SHOW INVRN BASE TEMPS APRCHG -20C OVER THE NW BY LATE FRI). WL TEND TOWARD THE LO SIDE OF MOS GUIDANCE GIVEN HI STABILITY/SHALLOW NATURE OF ENCROACHING ARCTIC AIR. ON FRI NGT/SAT...UPR CONFLUENCE ZN PROGGED TO PUSH FAR ENUF S THAT DRY ARCTIC HI PRES CENTER DRIFTS OVER THE FA. WL DIMINISH POPS TO NO HIER THAN 30 NR LK SUP ON LATE FRI NGT/SAT TO REFLECT INCRSGLY HOSTILE CONDITIONS FOR LES. MADE A FEW CHGS TO THE SAT NGT/SUN PD TO REFLECT TREND TOWARD MORE AGGRESSIVE NRN BRANCH THAT WL AT LEAST DELAY THE PROGRESSION OF THE SW UPR TROF TO THE NE. IN GENERAL CUT POPS A BIT DURING THIS TIME WITH GREATER INFLUENCE OF DRIER NRN BRANCH. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) KC (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 330 AM EST THU JAN 11 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WSW FLOW ALF BTWN DEEPENING TROF OVER THE PAC NW (12Z-24Z H3 HGT FALLS UP TO 200M THERE WITH SHRTWV DIGGING ALG THE PAC NW COAST) AND UPR RDG AXIS MOVING INTO SE ONTARIO. STRONG SHRTWV EMBEDDED WITHIN THIS FLOW IS MOVING INTO SRN MANITOBA...WITH ONLY WEAK SFC LO OVER ERN ND JUST NW OF FAR. STRONG ISENTROPIC ASCENT NOTED IN ADVANCE OF THIS SHRTWV... AND MQT VWP SHOWS S WINDS UP TO 55KT AT 3K FT MSL. GALE FORCE WINDS OBSVD OVER LK SUP FM ISLE ROYALE TO STANNARD ROCK. STRONG WAD HAS CONTRIBUTED TO EXTENSIVE MID CLD DECK OVER THE UPR GRT LKS...BUT DRY AIR SHOWN ON THE 00Z GRB RAOBS/ TAMDAR SDNG FM SAW BTWN H9-775 OR SO HAS RESTRICTED SN FOR THE MOST PART TO THE COLD SIDE OF H85 WARM FNT...LOCATED AT 00Z FM CKC-CMX-ERY...WHERE 0Z GFS F6 ALSO SHOWS SOME UPR DVGC. LTL IF ANY PCPN NOTED CLOSER TO THE SFC LO AND ALG ATTENDANT LO PRES TROF STRETCHING TO THE SW AS 00Z BIS/ABR/MPX SDNGS EXCESSIVELY DRY. MUCH COLDER AIR OBSVD OVER MT/ADJOINING AREAS IN SRN CAN. MAIN FCST CONCERNS THIS PACKAGE ARE PCPN CHCS ASSOCIATED WITH SHRTWV/SFC LO TO THE WNW TDAY AND THEN DISTURBANCES IN WSW FLOW ALF IN THE WAKE OF THIS SHRTWV LATER AS VERY COLD AIR TO THE NW POISED TO MOVE INTO THE UPR GRT LKS. FOR TDAY...NAM/GFS/UKMET SHOW SFC LO OVER NE MN THIS MRNG MOVING ACRS NRN LK SUP INTO SE ONTARIO BY 00Z AS SHRTV NR LK WINNIPEG SHEARS ENE ACRS ONTARIO...WITH ATTENDANT LO PRES TROF DRIFTING INTO THE CNTRL ZNS BY 00Z FRI. GIVEN EXCESSIVELY DRY AIRMASS UPSTREAM AT BIS/MPX/ ABR...PREFER THE DRIER NAM FCST (ZERO QPF) AS SHARPER ISENTROPIC LIFT/H85-5 QVECTOR CNVGC/LINGERING UPR DVGC/DEEPER MSTR EXIT EARLY THIS MRNG AND GIVE WAY TO DRYING ALF/H85-5 QVECTOR DVGC BY 18Z. IN FACT...GFS FCST SDNGS DEPICT THIS MID LVL DRYING QUITE WELL ABV INCREASINGLY SHALLOW MOIST LYR. TDAY WL BE WARMEST DAY OF NEXT WEEK AT LEAST AS SW FLOW IN ADVANCE OF APRCHG LO PRES TROF ADVECTS WARMER AIR FM THE SW...WHERE HI TEMPS REACHED NR 40 OR SRN MN ON WED...INTO THE FA. GFS/UKMET/NAM SHOW A STRIPE OF HIER MID LVL RH DVLPG OVER THE NRN PLAINS THIS AFTN AND STREAKING ENE INTO THE WRN CWA LATE TDAY/TNGT/ FRI AS WAVES OF UPR DVGC IN RRQ OF H3 JET MAXES/SHRTWVS SHEARING ENEWD THRU WSW FLOW ALF IN CONFLUENCE ZN BTWN NRN/SRN BRANCHES AS WELL AS ACCOMPANYING H8-7 FGEN OVER RELATIVELY SHALLOW COLD AIR TO THE NW OF ARCTIC BNDRY NOW SEPARATING VERY COLD AIR IN MT/SRN CAN FM WARMER AIR STILL IN THE NRN PLAINS/MN THAT IS FCST TO GRDLY OOZE SE ACRS THE UPR LKS. THINK TRYING TO TIME EACH OF THESE WAVES WL BE FRUITLESS ATTM...SO WL CARRY CHC POPS ACRS MOST OF THE AREA THRU FRI TO ACCOUNT FOR THIS FGEN FORCING/POTENTIAL LES AS COLDER AIR GRDLY OVERSPRDS THE FA. IN GENERAL...WL GO WITH HIER CHC POPS TO THE NW EARLY IN THE PD AND GRDLY SHIFT THE HIER POPS TO THE SE AS ARCTIC BNDRY DRIFTS SLOWLY SE WITH TIME. RELATIVELY SHALLOW DEPTH OF COLD AIR AS WELL AS NEUTRAL-ALMOST ACYC LARGER SCALE LLVL FLOW WOULD SUG ANY LES WL BE ON THE LGT SIDE DESPITE ARRIVAL OF MUCH COLDER AIR BLO SHALLOW INVRN (GFS/NAM SHOW INVRN BASE TEMPS APRCHG -20C OVER THE NW BY LATE FRI). WL TEND TOWARD THE LO SIDE OF MOS GUIDANCE GIVEN HI STABILITY/SHALLOW NATURE OF ENCROACHING ARCTIC AIR. ON FRI NGT/SAT...UPR CONFLUENCE ZN PROGGED TO PUSH FAR ENUF S THAT DRY ARCTIC HI PRES CENTER DRIFTS OVER THE FA. WL DIMINISH POPS TO NO HIER THAN 30 NR LK SUP ON LATE FRI NGT/SAT TO REFLECT INCRSGLY HOSTILE CONDITIONS FOR LES. MADE A FEW CHGS TO THE SAT NGT/SUN PD TO REFLECT TREND TOWARD MORE AGGRESSIVE NRN BRANCH THAT WL AT LEAST DELAY THE PROGRESSION OF THE SW UPR TROF TO THE NE. IN GENERAL CUT POPS A BIT DURING THIS TIME WITH GREATER INFLUENCE OF DRIER NRN BRANCH. COORDINATED WITH GRB. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING E HALF LAKE SUPERIOR UNTIL 8 AM EST. && $$ KC mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE GAYLORD MI 938 PM EST WED JAN 10 2007 ...CORRECTED WATCH/WARNING/ADVISORY STATEMENT BELOW... .UPDATE...SFC/RUC/SATELLITE/RADAR AND UPPER ANALYSIS SHOWING ELEVATED WARM FRONTAL ZONE DRAPED ACROSS NRN MICHIGAN WITH NICE H7-H5 FGEN AND ASSOCIATED MID LEVEL MOISTURE BAND FROM FAR NRN LAKE MICHIGAN TO FAR NE LOWER MICHIGAN. ECHOES SEEN ON RADAR ARE NOT HITTING THE SFC...AND ARE PURE VIRGA AT THIS POINT. THERE IS SOME MINOR LAKE EFFECT FLURRIES THAT HAVE BEEN PESTERING THE MANISTIQUE AREA THROUGH THE COURSE OF THE NIGHT...WHERE H8 TEMPS HAVE LINGERED AROUND THE -8C RANGE...BARELY COLD ENOUGH FOR DEEP ENOUGH OVER LAKE INSTABILITY...AND JUST ENOUGH FETCH TO RESULT IN FLURRIES. AIR IS WARMING ACROSS THIS ENTIRE AREA THROUGH THE NIGHT...AND LAKE EFFECT WILL COME TO AN END. LOW CLOUDS IN THIS AREA WILL FOLLOW...ENDING LATE TONIGHT. AS THE NIGHT WEARS ON...ELEVATED WARM FRONTAL/MOISTURE/FGEN BAND WILL LIFT INTO EASTERN UPPER MICHIGAN AND DEPART ALL BUT NRN CHIPPEWA COUNTY BY DAYBREAK. THIS AREA OF CONCERN WILL THEN LIFT OUT OF ALL OF EASTERN UPPER BY 15Z TOMORROW. BOTH GFS/NAM SHOWING STRONGER H8 WINDS/WAA DEVELOPING TONIGHT AND INTO EARLY TOMORROW MORNING...ALONG WITH EASTWARD ADVANCEMENT OF WEAKISH SHORTWAVE ENERGY AHEAD OF SFC LOW PRESSURE...WHICH WILL RIDE ACROSS EASTERN LAKE SUPERIOR TOMORROW AFTERNOON. THIS IS GOING TO RESULT IN A FEW CONCERNS... THE FGEN WILL STRENGTHEN OVERNIGHT RESULTING IN BETTER CHANCES FOR THE MOISTURE CHANNEL TO SQUEEZE OUT SOME LIGHT SNOW ACROSS MAINLY EASTERN UPPER/CHIPPEWA COUNTY...AND THROUGH MIDNIGHT FOR CHEBOYGAN AND PELLSTON AREAS AS WINDS HAVE BACKED INTO A E/ENE DIRECTION OFF LAKE HURON (POSSIBLE LAKE HELP). TOTAL OVERNIGHT SNOWFALL WILL BE MINIMAL AT BEST...BUT AN INCH IS NOT OUT OF THE QUESTION FOR EASTERN CHIP AND MACKINAC COUNTIES WITH A LITTLE EARLY HELP FROM LAKE HURON. ALSO...AS LOW LEVEL WINDS RAMP UP WITH H8 SPEEDS REACHING 50KTS...GALES BECOME A CONCERN...EVEN UNDER THE INCREASINGLY STABLE BOUNDARY LAYER. CURRENT WARNINGS IN EFFECT FOR THE NEARSHORE WATERS ALONG LAKE MICHIGAN LOOK REASONABLE ATTM WITH THE HELP OF COASTAL CONVERGENCE...BUT WITH WIND SPEEDS THIS STRONG...AND HIGH RESOLUTION NAM12 SUGGESTING A SHALLOW MIXED LAYER TAPPING INTO 35-40 KNOTS OVER THE MAJORITY OF THE NEARSHORE WATERS...WILL GO AHEAD AND EXPAND GALES TO ALL BUT THE STRAITS TO PRESQUE ISLE...WHERE THE SE-SW WINDS WILL RESULT IN MINIMAL OVER WATER TRAJECTORY. SURELY WOULD EXPECT TO SEE SPEEDS JUST OFF THE SFC...SUCH AS THE MACKINAC BRIDGE...AND IN THE HIGHER TERRAIN OF INTERIOR NRN LOWER MICHIGAN PICK UP INTO THE 20-30KT RANGE AT TIMES OVERNIGHT WITH HIGHER GUSTS AT THE BRIDGE. WILL INCLUDE STRONGER WINDS IN THE FORECAST FOR THESE AREAS. THIS WARMING AND STRONG WINDS WILL ALSO ALLOW FOR TEMPERATURES TO INCREASE THROUGH THE NIGHT...REACHING THE MIDDLE 20S TO LOWER 30S BY DAYBREAK. AVIATION...LOW LEVEL WIND SHEAR WILL ONLY RAMP UP FURTHER TONIGHT. APX VAD WINDS ONLY SHOWING 15-20KTS RIGHT NOW AT 2KFT...BUT 25-30KTS AT 2KFT ARE ALREADY SWEEPING INTO THE GTV BAY REGION. CURRENT TAFS ALREADY HAVE THIS SCENARIO LAID OUT...AND FORESEE NO CHANGES HERE AT THE 06Z ISSUANCES. MVFR CEILINGS TO REMAIN UP IN EASTERN UPPER WITH SOUTHERLY FLOW OFF FAR NRN LAKES MICHIGAN AND HURON...BUT LOW LEVEL MOISTURE CHANNEL IS EXPECTED TO DEVELOP AS EARLY AS LATE TONIGHT AND INTO THE TVC/PLN AIRPORTS. THIS IS PORTRAYED IN THE CURRENT TAFS AS WELL..AND FORESEE NO CHANGES TO THIS ATTM. SMD && .PREV DISCUSSION ISSUED AT 416 PM EST WED JAN 10 2007 DISCUSSION....EARLY THIS AFTERNOON...LATEST SURFACE/RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW HIGH PRESSURE OVER THE SOUTHERN PLAINS WHOSE SURFACE RIDGE AXIS BISECTS LOWER MICHIGAN. LOW LEVEL WINDS STARTING TO REFLECT THE AXIS PASSAGE WITH LIGHT LAKE EFFECT SNOW SHOWERS OVER NW LOWER AND TIP OF THE MITT DIMINISHING AS THE DISORGANIZED BANDS ARE TRYING TO ORIENT THEMSELVES IN THE SW-NE DIRECTION. THESE BANDS ARE ALSO FIGHTING PLENTY OF DRY AIR AS ACARS SOUNDINGS FROM PLN AND TVC SHOW INVERSION HEIGHTS CONTINUING TO FALL TO AROUND 860MB. AWAY FROM THE LES BANDS...SKIES HAVE TURNED PARTLY TO MOSTLY SUNNY. MEANWHILE UPSTREAM...STRONG SHORTWAVE NOW OVER ALBERTA AND ASSOCIATED LOW PRESSURE IS TRUCKING EAST ALONG THE CANADIAN BORDER...HELPING TO TIGHTEN THE PRESSURE GRADIENT OVER THE PLAINS. WARM AIR ADVECTION CLOUDS RIDING OVER THE 850MB WARM FRONT LOCATED OVER THE UPPER MISSISSIPPI RIVER VALLEY ARE STARTING TO CROSS LAKE MICHIGAN...AND WILL EVENTUALLY MAKE IT ACROSS THE CWA LATE THIS AFTERNOON/EVENING. THE INTERACTION OF THIS WARM FRONT AS IT MOVES NORTHEAST TONIGHT...AND WEAKENING LES WILL BE THE MAIN FORECAST CONCERN TONIGHT. TONIGHT...UPSTREAM SHORTWAVE WILL MAKE IT TO MANITOBA (ASSOCIATED SURFACE LOW PRESSURE TO WESTERN ONTARIO) BY 12Z THURSDAY MORNING. THIS WAVE WILL HELP INCREASE THE SOUTHERLY FLOW AHEAD OF IT AND PUSH A 850MB WARM FRONT TO THE NORTHEAST TO NORTHERN LOWER BY 12Z. AS IT DOES SO...850MB TEMPERATURES MODERATE ALOT FROM MINUS 6-9C AT 00Z OVER NORTHERN LAKE MICHIGAN TO 0 TO MINUS 3 BY 12Z. A SURGE OF MOISTURE WILL ACCOMPANY THIS WAA...WHICH REDUCES CONDENSATION PRESSURE DEFICITS ON THE 285K AND 290K ISENTROPIC SURFACES TO LESS THAN 10MB BY APPROXIMATELY 03Z. NAM/GFS SOUNDINGS DIFFER OVERNIGHT...WITH THE NAM NOT NEARLY AS MOIST BELOW 800MB AS THE GFS. WITH ONSHORE FLOW OVER EASTERN UPPER FROM LAKE MICHIGAN WHILE DELTA T/S REMAINING ABOVE 8C DURING THE EVENING...LIKE THE MORE MOIST SCENARIO DEPICTED BY THE GFS...AND WILL KEEP CHANCE POPS ACROSS EASTERN UPPER AFTER 03Z. LOWER LEVELS LOOK TO DRY OVER NORTHERN LOWER FOR PRECIP AT THIS TIME. TEMPERATURES WILL BOTTOM OUT DURING THE EVENING TONIGHT BUT THEN SLOWLY RISE OVERNIGHT WITH THE INCOMING WARM AIR. MARINE...TIGHTENING PRESSURE GRADIENT COMBINED WITH OVER-LAKE INSTABILITY AND COASTAL CONVERGENCE WILL CREATE WIND SPEEDS AT 925MB TO 40-50KTS TONIGHT AND GALE FORCE WIND GUSTS ALONG THE LAKE MICHIGAN SHORELINE FROM MANISTEE TO THE STRAITS. ELSEWHERE...MIXING TO 925MB REVEALS WIND GUSTS COULD POTENTIALLY REACH BETWEEN 30-35 KNOTS...OR JUST BELOW GALE FORCE...SO WILL INTRODUCE SMALL CRAFTS EVERYWHERE ELSE. MPC FOR THE REMAINDER OF THE WEEK...COLD AIR CONTINUES TO MODERATE AND RAPIDLY MOVE EAST OF THE REGION EARLY ON WHILE LOW AMPLITUDE MID LEVEL RIDGING DEVELOPS OVER THE EASTERN STATES...BUT NEXT CORE OF COLD AIR DESCENDS INTO THE NRN ROCKIES. ONE PIECE OF ENERGY (NOW NEAR LAKE WINNIPEG) FORECAST TO MOVE ACROSS SOUTHERN CANADA WITH AN ASSOCIATED LOW PRESSURE SYSTEM AND COLD FRONT SLOWING MOVING THROUGH AND IMPACTING THE REGION THURSDAY THROUGH FRIDAY. MAIN FORECAST ISSUES FOR THE NEAR TERM REVOLVE AROUND PRECIP CHANCES AND TYPE AS THIS SYSTEM PASSES THROUGH. THURSDAY...AS MENTIONED ABOVE...NRN STREAM SHORTWAVE AND ASSOCIATED SFC LOW FORECAST TO SLOWLY MOVE INTO ONTARIO DURING THE DAY...WITH A WARM FRONT LIFTING THROUGH THE REGION OVERNIGHT/EARLY THURSDAY AND TRAILING COLD FRONT APPROACHING THE REGION BY LATE AFTERNOON. DECENT SHOT OF WARM ADVECTION MAY BE ENOUGH TO PRODUCE BAND OF LIGHT SNOWFALL ACROSS EASTERN UPPER MICHIGAN THURSDAY MORNING AND WILL KEEP A CHANCE GOING IN THE FORECAST FOR THAT AREA...ALTHOUGH LOWER LAYERS ARE A BIT ON THE DRY SIDE. BUT WITHOUT ANY HELP FROM THE LAKES (TEMPS TOO WARM) ANY ACCUMULATIONS SHOULD BE ON THE LIGHT SIDE. THURSDAY AFTERNOON...NORTHERN MICHIGAN WELL INTO THE WARM SECTOR WITH STRONG SW WINDS CONTINUING AND AFTERNOON TEMPS WARMING BACK INTO THE 30S TO AROUND 40 (WOULD BE EVEN WARMER WERE IT NOT FOR THE SNOW COVER). MEANWHILE...BOTH NAM AND PARTICULARLY THE GFS DEPICT SUBSTANTIAL MOISTENING IN THE SUB 800 MB LAYER DURING THE AFTERNOON (WARMER THAN -6C) AHEAD OF THE APPROACHING FRONT...WHILE MOISTURE ALOFT STRIPS OUT. NOT MUCH OUT THERE UPSTREAM TODAY IN TERMS OF LOW CLOUDS TO HANG YOUR HAT ON...BUT CAN SEE THIS TAKING SHAPE AS WARMER/MOIST AIR SURGES NORTH ACROSS THE SNOW COVER IN NORTHERN MICHIGAN. REMOVED MENTION OF ANY RAIN/SNOW FROM THE FORECAST FOR THE AFTERNOON...BUT MAY BE ENOUGH MOISTURE THERE TO GET SOME DRIZZLE GOING ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. THURSDAY NIGHT THROUGH FRIDAY...COLD FRONT SLOWLY PRESSES EAST/SE THROUGH THE AREA THURSDAY NIGHT INTO EARLY FRIDAY AND SETTLE TO OUR SOUTH. ALTHOUGH STILL QUITE A BIT OF UNCERTAINLY REGARDING POPS DURING THIS TIMEFRAME...PERHAPS ENOUGH FORCING/MOISTURE ALONG THE FRONT TO SQUEEZE OUT MEASURABLE PRECIP BOTH THURSDAY NIGHT INTO FRIDAY...WITH PRIMARILY SNOW OVER THE NRN TWO-THIRDS OF THE CWA AND RAIN/SNOW OVER THE SOUTH. ALSO...AS COLDER AIR SLOWLY FILTERS INTO THE REGION...SHOULD START TO GET THE LAKES MORE INVOLVED BY FRIDAY. BUT OVERALL ACCUMULATIONS LOOKING TO BE ON THE MINOR SIDE AT THIS POINT. SATURDAY THRU WEDNESDAY...FRONT CONTINUES TO SAG SOUTH OF THE REGION BY EARLY SATURDAY WITH COLDER AIR ONCE AGAIN SETTLING INTO THE STATE FOR THE WEEKEND. SPLIT FLOW REGIME EMERGES ACROSS THE LOWER 48 STATES BY THE END OF THE WEEK AND HEADING INTO THE WEEKEND...WITH A CLOSED MID LEVEL LOW SLOWLY DROPPING SOUTHWARD ALONG THE WEST COAST INTO THE 4 CORNERS REGION AND LOW AMPLITUDE RIDGING OVER THE EASTERN HALF OF THE CONUS. LATEST MEDIUM RANGE GUIDANCE SUGGESTS BROAD NRN STREAM HIGH PRESSURE WILL SETTLE ACROSS THE NRN PLAINS AND WESTERN GREAT LAKES SATURDAY INTO EARLY SUNDAY WITH TEMPS RUNNING NEAR NORMAL. STILL COLD ENOUGH HOWEVER FOR SOME LIGHT LAKE SNOW SHOWERS DURING THIS TIME ALTHOUGH PROBLEMATIC THIS FAR OUT TO PINPOINT THE EXACT FLOW REGIME AND LOCATIONS WITH THE BEST CHANCES FOR SNOW. BY LATE IN THE WEEKEND AND EARLY NEXT WEEK...SRN STREAM CUTOFF SYSTEM LOOKING TO LIFT THROUGH THE OHIO VALLEY AND INTO NEW ENGLAND. SYSTEM COULD PRODUCE A DECENT AMOUNT OF SNOW (SYSTEM AND LAKE ENHANCED) ACROSS LOWER MICHIGAN IF CURRENT SCENARIO PANS OUT. THEN AGAIN... MEDIUM RANGE SOLUTIONS HAVE SHOWN A GOOD AMOUNT OF UNCERTAINTY WITH REGARD TO LOCATION OF THE STORM TRACK AND TIMING/LOCATION OF DEEPENING WAVES RIDING ALONG THE BAROCLINIC ZONE UP THROUGH THE REGION. BEHIND THIS SYSTEM AS IT STANDS RIGHT NOW...SOME OF THE COLDEST AIR OF THE YEAR GETS PULLED INTO NRN MICHIGAN FOR TUESDAY AND WEDNESDAY...WHILE STRONG HIGH PRESSURE BUILDS INTO THE PLAINS AND WESTERN GREAT LAKES. HOWEVER...WITH THE COLD AIR IN PLACE WILL HAVE CONTINUING CHANCES FOR SNOW SHOWERS. ADAM && .APX...WATCHES/WARNINGS/ADVISORIES... GALE WARNING...TONIGHT THROUGH THURSDAY.... LMZ323-341-342-344-345-LSZ321-LHZ346-348-349. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 938 PM EST WED JAN 10 2007 .UPDATE...SFC/RUC/SATELLITE/RADAR AND UPPER ANALYSIS SHOWING ELEVATED WARM FRONTAL ZONE DRAPED ACROSS NRN MICHIGAN WITH NICE H7-H5 FGEN AND ASSOCIATED MID LEVEL MOISTURE BAND FROM FAR NRN LAKE MICHIGAN TO FAR NE LOWER MICHIGAN. ECHOES SEEN ON RADAR ARE NOT HITTING THE SFC...AND ARE PURE VIRGA AT THIS POINT. THERE IS SOME MINOR LAKE EFFECT FLURRIES THAT HAVE BEEN PESTERING THE MANISTIQUE AREA THROUGH THE COURSE OF THE NIGHT...WHERE H8 TEMPS HAVE LINGERED AROUND THE -8C RANGE...BARELY COLD ENOUGH FOR DEEP ENOUGH OVER LAKE INSTABILITY...AND JUST ENOUGH FETCH TO RESULT IN FLURRIES. AIR IS WARMING ACROSS THIS ENTIRE AREA THROUGH THE NIGHT...AND LAKE EFFECT WILL COME TO AN END. LOW CLOUDS IN THIS AREA WILL FOLLOW...ENDING LATE TONIGHT. AS THE NIGHT WEARS ON...ELEVATED WARM FRONTAL/MOISTURE/FGEN BAND WILL LIFT INTO EASTERN UPPER MICHIGAN AND DEPART ALL BUT NRN CHIPPEWA COUNTY BY DAYBREAK. THIS AREA OF CONCERN WILL THEN LIFT OUT OF ALL OF EASTERN UPPER BY 15Z TOMORROW. BOTH GFS/NAM SHOWING STRONGER H8 WINDS/WAA DEVELOPING TONIGHT AND INTO EARLY TOMORROW MORNING...ALONG WITH EASTWARD ADVANCEMENT OF WEAKISH SHORTWAVE ENERGY AHEAD OF SFC LOW PRESSURE...WHICH WILL RIDE ACROSS EASTERN LAKE SUPERIOR TOMORROW AFTERNOON. THIS IS GOING TO RESULT IN A FEW CONCERNS... THE FGEN WILL STRENGTHEN OVERNIGHT RESULTING IN BETTER CHANCES FOR THE MOISTURE CHANNEL TO SQUEEZE OUT SOME LIGHT SNOW ACROSS MAINLY EASTERN UPPER/CHIPPEWA COUNTY...AND THROUGH MIDNIGHT FOR CHEBOYGAN AND PELLSTON AREAS AS WINDS HAVE BACKED INTO A E/ENE DIRECTION OFF LAKE HURON (POSSIBLE LAKE HELP). TOTAL OVERNIGHT SNOWFALL WILL BE MINIMAL AT BEST...BUT AN INCH IS NOT OUT OF THE QUESTION FOR EASTERN CHIP AND MACKINAC COUNTIES WITH A LITTLE EARLY HELP FROM LAKE HURON. ALSO...AS LOW LEVEL WINDS RAMP UP WITH H8 SPEEDS REACHING 50KTS...GALES BECOME A CONCERN...EVEN UNDER THE INCREASINGLY STABLE BOUNDARY LAYER. CURRENT WARNINGS IN EFFECT FOR THE NEARSHORE WATERS ALONG LAKE MICHIGAN LOOK REASONABLE ATTM WITH THE HELP OF COASTAL CONVERGENCE...BUT WITH WIND SPEEDS THIS STRONG...AND HIGH RESOLUTION NAM12 SUGGESTING A SHALLOW MIXED LAYER TAPPING INTO 35-40 KNOTS OVER THE MAJORITY OF THE NEARSHORE WATERS...WILL GO AHEAD AND EXPAND GALES TO ALL BUT THE STRAITS TO PRESQUE ISLE...WHERE THE SE-SW WINDS WILL RESULT IN MINIMAL OVER WATER TRAJECTORY. SURELY WOULD EXPECT TO SEE SPEEDS JUST OFF THE SFC...SUCH AS THE MACKINAC BRIDGE...AND IN THE HIGHER TERRAIN OF INTERIOR NRN LOWER MICHIGAN PICK UP INTO THE 20-30KT RANGE AT TIMES OVERNIGHT WITH HIGHER GUSTS AT THE BRIDGE. WILL INCLUDE STRONGER WINDS IN THE FORECAST FOR THESE AREAS. THIS WARMING AND STRONG WINDS WILL ALSO ALLOW FOR TEMPERATURES TO INCREASE THROUGH THE NIGHT...REACHING THE MIDDLE 20S TO LOWER 30S BY DAYBREAK. AVIATION...LOW LEVEL WIND SHEAR WILL ONLY RAMP UP FURTHER TONIGHT. APX VAD WINDS ONLY SHOWING 15-20KTS RIGHT NOW AT 2KFT...BUT 25-30KTS AT 2KFT ARE ALREADY SWEEPING INTO THE GTV BAY REGION. CURRENT TAFS ALREADY HAVE THIS SCENARIO LAID OUT...AND FORESEE NO CHANGES HERE AT THE 06Z ISSUANCES. MVFR CEILINGS TO REMAIN UP IN EASTERN UPPER WITH SOUTHERLY FLOW OFF FAR NRN LAKES MICHIGAN AND HURON...BUT LOW LEVEL MOISTURE CHANNEL IS EXPECTED TO DEVELOP AS EARLY AS LATE TONIGHT AND INTO THE TVC/PLN AIRPORTS. THIS IS PORTRAYED IN THE CURRENT TAFS AS WELL..AND FORESEE NO CHANGES TO THIS ATTM. SMD && .PREV DISCUSSION ISSUED AT 416 PM EST WED JAN 10 2007 DISCUSSION....EARLY THIS AFTERNOON...LATEST SURFACE/RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW HIGH PRESSURE OVER THE SOUTHERN PLAINS WHOSE SURFACE RIDGE AXIS BISECTS LOWER MICHIGAN. LOW LEVEL WINDS STARTING TO REFLECT THE AXIS PASSAGE WITH LIGHT LAKE EFFECT SNOW SHOWERS OVER NW LOWER AND TIP OF THE MITT DIMINISHING AS THE DISORGANIZED BANDS ARE TRYING TO ORIENT THEMSELVES IN THE SW-NE DIRECTION. THESE BANDS ARE ALSO FIGHTING PLENTY OF DRY AIR AS ACARS SOUNDINGS FROM PLN AND TVC SHOW INVERSION HEIGHTS CONTINUING TO FALL TO AROUND 860MB. AWAY FROM THE LES BANDS...SKIES HAVE TURNED PARTLY TO MOSTLY SUNNY. MEANWHILE UPSTREAM...STRONG SHORTWAVE NOW OVER ALBERTA AND ASSOCIATED LOW PRESSURE IS TRUCKING EAST ALONG THE CANADIAN BORDER...HELPING TO TIGHTEN THE PRESSURE GRADIENT OVER THE PLAINS. WARM AIR ADVECTION CLOUDS RIDING OVER THE 850MB WARM FRONT LOCATED OVER THE UPPER MISSISSIPPI RIVER VALLEY ARE STARTING TO CROSS LAKE MICHIGAN...AND WILL EVENTUALLY MAKE IT ACROSS THE CWA LATE THIS AFTERNOON/EVENING. THE INTERACTION OF THIS WARM FRONT AS IT MOVES NORTHEAST TONIGHT...AND WEAKENING LES WILL BE THE MAIN FORECAST CONCERN TONIGHT. TONIGHT...UPSTREAM SHORTWAVE WILL MAKE IT TO MANITOBA (ASSOCIATED SURFACE LOW PRESSURE TO WESTERN ONTARIO) BY 12Z THURSDAY MORNING. THIS WAVE WILL HELP INCREASE THE SOUTHERLY FLOW AHEAD OF IT AND PUSH A 850MB WARM FRONT TO THE NORTHEAST TO NORTHERN LOWER BY 12Z. AS IT DOES SO...850MB TEMPERATURES MODERATE ALOT FROM MINUS 6-9C AT 00Z OVER NORTHERN LAKE MICHIGAN TO 0 TO MINUS 3 BY 12Z. A SURGE OF MOISTURE WILL ACCOMPANY THIS WAA...WHICH REDUCES CONDENSATION PRESSURE DEFICITS ON THE 285K AND 290K ISENTROPIC SURFACES TO LESS THAN 10MB BY APPROXIMATELY 03Z. NAM/GFS SOUNDINGS DIFFER OVERNIGHT...WITH THE NAM NOT NEARLY AS MOIST BELOW 800MB AS THE GFS. WITH ONSHORE FLOW OVER EASTERN UPPER FROM LAKE MICHIGAN WHILE DELTA T/S REMAINING ABOVE 8C DURING THE EVENING...LIKE THE MORE MOIST SCENARIO DEPICTED BY THE GFS...AND WILL KEEP CHANCE POPS ACROSS EASTERN UPPER AFTER 03Z. LOWER LEVELS LOOK TO DRY OVER NORTHERN LOWER FOR PRECIP AT THIS TIME. TEMPERATURES WILL BOTTOM OUT DURING THE EVENING TONIGHT BUT THEN SLOWLY RISE OVERNIGHT WITH THE INCOMING WARM AIR. MARINE...TIGHTENING PRESSURE GRADIENT COMBINED WITH OVER-LAKE INSTABILITY AND COASTAL CONVERGENCE WILL CREATE WIND SPEEDS AT 925MB TO 40-50KTS TONIGHT AND GALE FORCE WIND GUSTS ALONG THE LAKE MICHIGAN SHORELINE FROM MANISTEE TO THE STRAITS. ELSEWHERE...MIXING TO 925MB REVEALS WIND GUSTS COULD POTENTIALLY REACH BETWEEN 30-35 KNOTS...OR JUST BELOW GALE FORCE...SO WILL INTRODUCE SMALL CRAFTS EVERYWHERE ELSE. MPC FOR THE REMAINDER OF THE WEEK...COLD AIR CONTINUES TO MODERATE AND RAPIDLY MOVE EAST OF THE REGION EARLY ON WHILE LOW AMPLITUDE MID LEVEL RIDGING DEVELOPS OVER THE EASTERN STATES...BUT NEXT CORE OF COLD AIR DESCENDS INTO THE NRN ROCKIES. ONE PIECE OF ENERGY (NOW NEAR LAKE WINNIPEG) FORECAST TO MOVE ACROSS SOUTHERN CANADA WITH AN ASSOCIATED LOW PRESSURE SYSTEM AND COLD FRONT SLOWING MOVING THROUGH AND IMPACTING THE REGION THURSDAY THROUGH FRIDAY. MAIN FORECAST ISSUES FOR THE NEAR TERM REVOLVE AROUND PRECIP CHANCES AND TYPE AS THIS SYSTEM PASSES THROUGH. THURSDAY...AS MENTIONED ABOVE...NRN STREAM SHORTWAVE AND ASSOCIATED SFC LOW FORECAST TO SLOWLY MOVE INTO ONTARIO DURING THE DAY...WITH A WARM FRONT LIFTING THROUGH THE REGION OVERNIGHT/EARLY THURSDAY AND TRAILING COLD FRONT APPROACHING THE REGION BY LATE AFTERNOON. DECENT SHOT OF WARM ADVECTION MAY BE ENOUGH TO PRODUCE BAND OF LIGHT SNOWFALL ACROSS EASTERN UPPER MICHIGAN THURSDAY MORNING AND WILL KEEP A CHANCE GOING IN THE FORECAST FOR THAT AREA...ALTHOUGH LOWER LAYERS ARE A BIT ON THE DRY SIDE. BUT WITHOUT ANY HELP FROM THE LAKES (TEMPS TOO WARM) ANY ACCUMULATIONS SHOULD BE ON THE LIGHT SIDE. THURSDAY AFTERNOON...NORTHERN MICHIGAN WELL INTO THE WARM SECTOR WITH STRONG SW WINDS CONTINUING AND AFTERNOON TEMPS WARMING BACK INTO THE 30S TO AROUND 40 (WOULD BE EVEN WARMER WERE IT NOT FOR THE SNOW COVER). MEANWHILE...BOTH NAM AND PARTICULARLY THE GFS DEPICT SUBSTANTIAL MOISTENING IN THE SUB 800 MB LAYER DURING THE AFTERNOON (WARMER THAN -6C) AHEAD OF THE APPROACHING FRONT...WHILE MOISTURE ALOFT STRIPS OUT. NOT MUCH OUT THERE UPSTREAM TODAY IN TERMS OF LOW CLOUDS TO HANG YOUR HAT ON...BUT CAN SEE THIS TAKING SHAPE AS WARMER/MOIST AIR SURGES NORTH ACROSS THE SNOW COVER IN NORTHERN MICHIGAN. REMOVED MENTION OF ANY RAIN/SNOW FROM THE FORECAST FOR THE AFTERNOON...BUT MAY BE ENOUGH MOISTURE THERE TO GET SOME DRIZZLE GOING ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. THURSDAY NIGHT THROUGH FRIDAY...COLD FRONT SLOWLY PRESSES EAST/SE THROUGH THE AREA THURSDAY NIGHT INTO EARLY FRIDAY AND SETTLE TO OUR SOUTH. ALTHOUGH STILL QUITE A BIT OF UNCERTAINLY REGARDING POPS DURING THIS TIMEFRAME...PERHAPS ENOUGH FORCING/MOISTURE ALONG THE FRONT TO SQUEEZE OUT MEASURABLE PRECIP BOTH THURSDAY NIGHT INTO FRIDAY...WITH PRIMARILY SNOW OVER THE NRN TWO-THIRDS OF THE CWA AND RAIN/SNOW OVER THE SOUTH. ALSO...AS COLDER AIR SLOWLY FILTERS INTO THE REGION...SHOULD START TO GET THE LAKES MORE INVOLVED BY FRIDAY. BUT OVERALL ACCUMULATIONS LOOKING TO BE ON THE MINOR SIDE AT THIS POINT. SATURDAY THRU WEDNESDAY...FRONT CONTINUES TO SAG SOUTH OF THE REGION BY EARLY SATURDAY WITH COLDER AIR ONCE AGAIN SETTLING INTO THE STATE FOR THE WEEKEND. SPLIT FLOW REGIME EMERGES ACROSS THE LOWER 48 STATES BY THE END OF THE WEEK AND HEADING INTO THE WEEKEND...WITH A CLOSED MID LEVEL LOW SLOWLY DROPPING SOUTHWARD ALONG THE WEST COAST INTO THE 4 CORNERS REGION AND LOW AMPLITUDE RIDGING OVER THE EASTERN HALF OF THE CONUS. LATEST MEDIUM RANGE GUIDANCE SUGGESTS BROAD NRN STREAM HIGH PRESSURE WILL SETTLE ACROSS THE NRN PLAINS AND WESTERN GREAT LAKES SATURDAY INTO EARLY SUNDAY WITH TEMPS RUNNING NEAR NORMAL. STILL COLD ENOUGH HOWEVER FOR SOME LIGHT LAKE SNOW SHOWERS DURING THIS TIME ALTHOUGH PROBLEMATIC THIS FAR OUT TO PINPOINT THE EXACT FLOW REGIME AND LOCATIONS WITH THE BEST CHANCES FOR SNOW. BY LATE IN THE WEEKEND AND EARLY NEXT WEEK...SRN STREAM CUTOFF SYSTEM LOOKING TO LIFT THROUGH THE OHIO VALLEY AND INTO NEW ENGLAND. SYSTEM COULD PRODUCE A DECENT AMOUNT OF SNOW (SYSTEM AND LAKE ENHANCED) ACROSS LOWER MICHIGAN IF CURRENT SCENARIO PANS OUT. THEN AGAIN... MEDIUM RANGE SOLUTIONS HAVE SHOWN A GOOD AMOUNT OF UNCERTAINTY WITH REGARD TO LOCATION OF THE STORM TRACK AND TIMING/LOCATION OF DEEPENING WAVES RIDING ALONG THE BAROCLINIC ZONE UP THROUGH THE REGION. BEHIND THIS SYSTEM AS IT STANDS RIGHT NOW...SOME OF THE COLDEST AIR OF THE YEAR GETS PULLED INTO NRN MICHIGAN FOR TUESDAY AND WEDNESDAY...WHILE STRONG HIGH PRESSURE BUILDS INTO THE PLAINS AND WESTERN GREAT LAKES. HOWEVER...WITH THE COLD AIR IN PLACE WILL HAVE CONTINUING CHANCES FOR SNOW SHOWERS. ADAM && .APX...WATCHES/WARNINGS/ADVISORIES...GALE WARNING...TONIGHT THROUGH THURSDAY....LMZ323-342-344-345. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 416 PM EST WED JAN 10 2007 .DISCUSSION....EARLY THIS AFTERNOON...LATEST SURFACE/RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW HIGH PRESSURE OVER THE SOUTHERN PLAINS WHOSE SURFACE RIDGE AXIS BISECTS LOWER MICHIGAN. LOW LEVEL WINDS STARTING TO REFLECT THE AXIS PASSAGE WITH LIGHT LAKE EFFECT SNOW SHOWERS OVER NW LOWER AND TIP OF THE MITT DIMINISHING AS THE DISORGANIZED BANDS ARE TRYING TO ORIENT THEMSELVES IN THE SW-NE DIRECTION. THESE BANDS ARE ALSO FIGHTING PLENTY OF DRY AIR AS ACARS SOUNDINGS FROM PLN AND TVC SHOW INVERSION HEIGHTS CONTINUING TO FALL TO AROUND 860MB. AWAY FROM THE LES BANDS...SKIES HAVE TURNED PARTLY TO MOSTLY SUNNY. MEANWHILE UPSTREAM...STRONG SHORTWAVE NOW OVER ALBERTA AND ASSOCIATED LOW PRESSURE IS TRUCKING EAST ALONG THE CANADIAN BORDER...HELPING TO TIGHTEN THE PRESSURE GRADIENT OVER THE PLAINS. WARM AIR ADVECTION CLOUDS RIDING OVER THE 850MB WARM FRONT LOCATED OVER THE UPPER MISSISSIPPI RIVER VALLEY ARE STARTING TO CROSS LAKE MICHIGAN...AND WILL EVENTUALLY MAKE IT ACROSS THE CWA LATE THIS AFTERNOON/EVENING. THE INTERACTION OF THIS WARM FRONT AS IT MOVES NORTHEAST TONIGHT...AND WEAKENING LES WILL BE THE MAIN FORECAST CONCERN TONIGHT. TONIGHT...UPSTREAM SHORTWAVE WILL MAKE IT TO MANITOBA (ASSOCIATED SURFACE LOW PRESSURE TO WESTERN ONTARIO) BY 12Z THURSDAY MORNING. THIS WAVE WILL HELP INCREASE THE SOUTHERLY FLOW AHEAD OF IT AND PUSH A 850MB WARM FRONT TO THE NORTHEAST TO NORTHERN LOWER BY 12Z. AS IT DOES SO...850MB TEMPERATURES MODERATE ALOT FROM MINUS 6-9C AT 00Z OVER NORTHERN LAKE MICHIGAN TO 0 TO MINUS 3 BY 12Z. A SURGE OF MOISTURE WILL ACCOMPANY THIS WAA...WHICH REDUCES CONDENSATION PRESSURE DEFICITS ON THE 285K AND 290K ISENTROPIC SURFACES TO LESS THAN 10MB BY APPROXIMATELY 03Z. NAM/GFS SOUNDINGS DIFFER OVERNIGHT...WITH THE NAM NOT NEARLY AS MOIST BELOW 800MB AS THE GFS. WITH ONSHORE FLOW OVER EASTERN UPPER FROM LAKE MICHIGAN WHILE DELTA T/S REMAINING ABOVE 8C DURING THE EVENING...LIKE THE MORE MOIST SCENARIO DEPICTED BY THE GFS...AND WILL KEEP CHANCE POPS ACROSS EASTERN UPPER AFTER 03Z. LOWER LEVELS LOOK TO DRY OVER NORTHERN LOWER FOR PRECIP AT THIS TIME. TEMPERATURES WILL BOTTOM OUT DURING THE EVENING TONIGHT BUT THEN SLOWLY RISE OVERNIGHT WITH THE INCOMING WARM AIR. MARINE...TIGHTENING PRESSURE GRADIENT COMBINED WITH OVER-LAKE INSTABILITY AND COASTAL CONVERGENCE WILL CREATE WIND SPEEDS AT 925MB TO 40-50KTS TONIGHT AND GALE FORCE WIND GUSTS ALONG THE LAKE MICHIGAN SHORELINE FROM MANISTEE TO THE STRAITS. ELSEWHERE...MIXING TO 925MB REVEALS WIND GUSTS COULD POTENTIALLY REACH BETWEEN 30-35 KNOTS...OR JUST BELOW GALE FORCE...SO WILL INTRODUCE SMALL CRAFTS EVERYWHERE ELSE. MPC FOR THE REMAINDER OF THE WEEK...COLD AIR CONTINUES TO MODERATE AND RAPIDLY MOVE EAST OF THE REGION EARLY ON WHILE LOW AMPLITUDE MID LEVEL RIDGING DEVELOPS OVER THE EASTERN STATES...BUT NEXT CORE OF COLD AIR DESCENDS INTO THE NRN ROCKIES. ONE PIECE OF ENERGY (NOW NEAR LAKE WINNIPEG) FORECAST TO MOVE ACROSS SOUTHERN CANADA WITH AN ASSOCIATED LOW PRESSURE SYSTEM AND COLD FRONT SLOWING MOVING THROUGH AND IMPACTING THE REGION THURSDAY THROUGH FRIDAY. MAIN FORECAST ISSUES FOR THE NEAR TERM REVOLVE AROUND PRECIP CHANCES AND TYPE AS THIS SYSTEM PASSES THROUGH. THURSDAY...AS MENTIONED ABOVE...NRN STREAM SHORTWAVE AND ASSOCIATED SFC LOW FORECAST TO SLOWLY MOVE INTO ONTARIO DURING THE DAY...WITH A WARM FRONT LIFTING THROUGH THE REGION OVERNIGHT/EARLY THURSDAY AND TRAILING COLD FRONT APPROACHING THE REGION BY LATE AFTERNOON. DECENT SHOT OF WARM ADVECTION MAY BE ENOUGH TO PRODUCE BAND OF LIGHT SNOWFALL ACROSS EASTERN UPPER MICHIGAN THURSDAY MORNING AND WILL KEEP A CHANCE GOING IN THE FORECAST FOR THAT AREA...ALTHOUGH LOWER LAYERS ARE A BIT ON THE DRY SIDE. BUT WITHOUT ANY HELP FROM THE LAKES (TEMPS TOO WARM) ANY ACCUMULATIONS SHOULD BE ON THE LIGHT SIDE. THURSDAY AFTERNOON...NORTHERN MICHIGAN WELL INTO THE WARM SECTOR WITH STRONG SW WINDS CONTINUING AND AFTERNOON TEMPS WARMING BACK INTO THE 30S TO AROUND 40 (WOULD BE EVEN WARMER WERE IT NOT FOR THE SNOW COVER). MEANWHILE...BOTH NAM AND PARTICULARLY THE GFS DEPICT SUBSTANTIAL MOISTENING IN THE SUB 800 MB LAYER DURING THE AFTERNOON (WARMER THAN -6C) AHEAD OF THE APPROACHING FRONT...WHILE MOISTURE ALOFT STRIPS OUT. NOT MUCH OUT THERE UPSTREAM TODAY IN TERMS OF LOW CLOUDS TO HANG YOUR HAT ON...BUT CAN SEE THIS TAKING SHAPE AS WARMER/MOIST AIR SURGES NORTH ACROSS THE SNOW COVER IN NORTHERN MICHIGAN. REMOVED MENTION OF ANY RAIN/SNOW FROM THE FORECAST FOR THE AFTERNOON...BUT MAY BE ENOUGH MOISTURE THERE TO GET SOME DRIZZLE GOING ESPECIALLY ACROSS THE HIGHER TERRAIN AREAS. THURSDAY NIGHT THROUGH FRIDAY...COLD FRONT SLOWLY PRESSES EAST/SE THROUGH THE AREA THURSDAY NIGHT INTO EARLY FRIDAY AND SETTLE TO OUR SOUTH. ALTHOUGH STILL QUITE A BIT OF UNCERTAINLY REGARDING POPS DURING THIS TIMEFRAME...PERHAPS ENOUGH FORCING/MOISTURE ALONG THE FRONT TO SQUEEZE OUT MEASURABLE PRECIP BOTH THURSDAY NIGHT INTO FRIDAY...WITH PRIMARILY SNOW OVER THE NRN TWO-THIRDS OF THE CWA AND RAIN/SNOW OVER THE SOUTH. ALSO...AS COLDER AIR SLOWLY FILTERS INTO THE REGION...SHOULD START TO GET THE LAKES MORE INVOLVED BY FRIDAY. BUT OVERALL ACCUMULATIONS LOOKING TO BE ON THE MINOR SIDE AT THIS POINT. SATURDAY THRU WEDNESDAY...FRONT CONTINUES TO SAG SOUTH OF THE REGION BY EARLY SATURDAY WITH COLDER AIR ONCE AGAIN SETTLING INTO THE STATE FOR THE WEEKEND. SPLIT FLOW REGIME EMERGES ACROSS THE LOWER 48 STATES BY THE END OF THE WEEK AND HEADING INTO THE WEEKEND...WITH A CLOSED MID LEVEL LOW SLOWLY DROPPING SOUTHWARD ALONG THE WEST COAST INTO THE 4 CORNERS REGION AND LOW AMPLITUDE RIDGING OVER THE EASTERN HALF OF THE CONUS. LATEST MEDIUM RANGE GUIDANCE SUGGESTS BROAD NRN STREAM HIGH PRESSURE WILL SETTLE ACROSS THE NRN PLAINS AND WESTERN GREAT LAKES SATURDAY INTO EARLY SUNDAY WITH TEMPS RUNNING NEAR NORMAL. STILL COLD ENOUGH HOWEVER FOR SOME LIGHT LAKE SNOW SHOWERS DURING THIS TIME ALTHOUGH PROBLEMATIC THIS FAR OUT TO PINPOINT THE EXACT FLOW REGIME AND LOCATIONS WITH THE BEST CHANCES FOR SNOW. BY LATE IN THE WEEKEND AND EARLY NEXT WEEK...SRN STREAM CUTOFF SYSTEM LOOKING TO LIFT THROUGH THE OHIO VALLEY AND INTO NEW ENGLAND. SYSTEM COULD PRODUCE A DECENT AMOUNT OF SNOW (SYSTEM AND LAKE ENHANCED) ACROSS LOWER MICHIGAN IF CURRENT SCENARIO PANS OUT. THEN AGAIN... MEDIUM RANGE SOLUTIONS HAVE SHOWN A GOOD AMOUNT OF UNCERTAINTY WITH REGARD TO LOCATION OF THE STORM TRACK AND TIMING/LOCATION OF DEEPENING WAVES RIDING ALONG THE BAROCLINIC ZONE UP THROUGH THE REGION. BEHIND THIS SYSTEM AS IT STANDS RIGHT NOW...SOME OF THE COLDEST AIR OF THE YEAR GETS PULLED INTO NRN MICHIGAN FOR TUESDAY AND WEDNESDAY...WHILE STRONG HIGH PRESSURE BUILDS INTO THE PLAINS AND WESTERN GREAT LAKES. HOWEVER...WITH THE COLD AIR IN PLACE WILL HAVE CONTINUING CHANCES FOR SNOW SHOWERS. ADAM && .APX...WATCHES/WARNINGS/ADVISORIES...GALE WARNING...TONIGHT THROUGH THURSDAY....LMZ323-342-344-345. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1128 AM EST WED JAN 10 2007 .UPDATE... LES IS WINDING DOWN STEADILY THIS MORNING AS HIGH PRES RIDGE MOVES ACROSS THE AREA. RIDGE CURRENTLY RUNS FROM LAKE MICHIGAN TO CNTRL LAKE SUPERIOR. UPSTREAM...VIGOROUS SHORTWAVE HEADING INTO SRN SASKATCHEWAN IS LEADING TO STRONG WAA PATTERN OVER THE NRN PLAINS. 12Z SOUNDING AT KBIS SHOWED 850MB TEMP OF 7C WITH SW WIND AT 35KT WHILE KINL/CYQD HAD 850MB TEMPS OF -11/-19C RESPECTIVELY. WAA/ISENTROPIC ASCENT REGIME HAS RESULTED IN MID CLOUD DECK FROM THE DAKOTAS ACROSS NRN MN. RADARS SHOW RETURNS FROM CLOUD DECK...BUT ONLY A FEW OBS HAVE SHOWN ANY SNOW IN NRN MN AS DRY AIRMASS PER 12Z KINL SOUNDING HAS KEPT MUCH OF THE SNOW FROM REACHING THE GROUND. LAST OF THE LES SHOULD END OVER THE FAR NE FCST AREA DURING THE NEXT FEW HRS AS WINDS BACK OFFSHORE WITH PASSAGE OF RIDGE AXIS. STRONG WAA REGIME WILL THEN BEGIN TO SPREAD E INTO WRN UPPER MI DURING THE AFTN...BUT EXPECT DRY AIR TO DELAY ONSET OF -SN SIGNIFICANTLY. RECENT TAMDAR SOUNDING FROM KSAW SHOWED DWPT DEPRESSIONS FROM 10 TO 25C BTWN 900 AND 700MB. INHERITED FCST LOOKED FINE JUST BRINGING CHC -SN TO WRN LAKE SUPERIOR DURING THE AFTN. && .PREV DISCUSSION... ISSUED AT 335 AM EST 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW TROF OVER ERN NAMERICA DOWNSTREAM OF UPR RDG BLDG INTO THE NRN PLAINS IN ADVANCE OF POTENT SHRTWV CRASHING INTO THE PAC NW (12Z-24Z H3 HGT FALL UP TO 250M IN NW WA STATE). CWA EARLY THIS MRNG REMAINS DOMINATED BY COLD AND GUSTY LLVL NW FLOW BTWN SFC HI PRES RDG APRCHG THE MS RIVER VALLEY AND DEEP LO PRES OVER QUEBEC. H85 TEMPS UPSTREAM STILL AS LO AS -21C AT YPL. ALTHOUGH LLVLS AT THIS SITE ARE RELATIVELY MOIST...ABSOLUTE MSTR IS LIMITED WITH SFC DWPTS BLO 0F IN MN AND ONTARIO NW OF LK SUP. 00Z INL SDNG IS QUITE A BIT DRIER THAN THE YPL SDNG CLOSER TO RDG AXIS...AND SKIES ARE MOCLR NOW IN THE MN ARROWHEAD. DESPITE THE VIGOROUS CAD OVER THE UPR LKS...THE COMBINATION OF THIS DRY AIR AND LO INVRN ARND H9 AS SHOWN ON THE 00Z INL/YPL RAOBS AS WELL AS TAMDAR SDNGS AT DLH/YQT HAVE NEGATIVELY IMPACTED LES AMTS EVEN OVER THE ERN ZNS WHERE LONGER FETCH ACRS THE LK HAS ALLOWED MORE LLVL MOISTENING AND DEEPER MIXED LYR UP TO H8 AS SHOWN ON THE 00Z TAMDAR SDNG FM SAW. NO MORE THAN 3-4 INCHES OF SN HAS FALLEN THRU 04Z. FARTHER UPSTREAM...MID/HI CLD IN WAD AHEAD OF SHRTWV MOVING INTO THE PAC NW HAS SPREAD THRU THE UPR RDG INTO NW MN. 00Z BIS SDNG IS QUITE DRY BLO H8...SO LEADING EDGE OF LGT SN TRAILS WELL BEHIND IN SE SASKATCHEWAN AT 04Z. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND LES TRENDS. FOCUS THEN SHIFTS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE PAC NW WITH CHC OF -SN AS EARLY AS THIS AFTN. FOR TDAY...NUMERICAL GUIDANCE SHOWS H5 HGT RISES UP TO 120M AS RDG IN THE PLAINS CONTINUES TO BLD EWD. SFC RDG AXIS PROGGED TO REACH NR IWD AT 12Z BEFORE PUSHING E OF ANJ BY 00Z THU. AS THE RDG AXIS/LOWER INVRN HGT APRCH FM THE W...EXPECT ONGOING LES TO END AND WINDS TO DIMINISH W-E. HAVE OPTED TO EXTEND THE LES ADVY (WITHOUT THE BLSN) OVER THE E A FEW HRS TO ACCOUNT FOR FVRBL CONDITIONS FOR MORE SHSN INTO MID MRNG. OTRW...BRIEF CLRG WL GIVE WAY TO INCRSG HI/MID CLD WITH ONSET OF ISENTROPIC ASCENT AS SHOWN ON THE 280-300K SFCS. SINCE LLVLS ON THE BIS SDNG ARE SO DRY AND ISENTROPIC ASCENT APPEARS TO BE THE ONLY FORCING MECHANISM FOR UPWARD MOTION WITH DPVA/UPR DVGC ASSOCIATED WITH SHRTWV NOW MOVING INTO THE PAC NW REMAINING TO THE NW THRU 00Z (SHRTWV ITSELF FCST TO REACH SE SASKATCHEWAN AT 00Z)... HAVE OPTED TO TAKE OUT THE WAD POPS TDAY OVER THE ENTIRE CWA PER VARIOUS MOS FCSTS. RESOLVE STRENGTHENED BECAUSE ISENTROPIC LIFT APPEARS TO BE GOING MORE TOWARD HORIZONTAL TEMP ADVCTN VS UVV AS PRES FCST TO RISE STEADILY ON THE ISENTROPIC SFCS IN QUESTION (I.E. STEADY WARMING)...NOT SURPRISING CONSIDERING TRACK OF SHRTWV WELL TO THE NW. OTRW...VARIOUS MOS FCST HI TEMPS CONSISTENT WITH READINGS EXPECTED FM EXPLICIT GFS FCST SDNGS. TNGT...SHRTWV OVER SRN CANADA FCST TO MOVE INTO NW ONTARIO BY 12Z THU. THERE IS SOME DISCREPANCY WITH REGARD TO THE POSITION OF SFC LO BY 12Z...WITH NAM FARTHEST TO THE NW JUST E OF LK WINNIPEG AND UKMET FARTHEST TO THE S NR DLH. 00Z GFS/12Z ECMWF LOOK TO BE A RSNBL COMPROMISE BTWN THESE SOLNS WITH SFC LO JUST N OF INL. GFS SHOWS BEST ISENTROPIC LIFT AS WELL AS DPVA/SHARPER H85-5 QVECTOR CNVGC/UPR DVGC TO THE N. CONSIDERING THE PLACEMENT OF THESE BETTER DYNAMICS AND LINGERING DRY AIR...HAVE OPTED TO RESTRICT CHC POPS TO OVER THE NRN TIER AND DOWNWIND OF LK MI WHERE STRONG SLY FLOW WL BE ABLE TO PICK UP SOME MSTR IN LONG FETCH OVER LK. IN FACT...GFS FCST SDNG FOR ERY AT 06Z SHOWS RELATIVELY DEEP MSTR...SO HIEST CHC POPS IN THIS LOCATION. OTRW...EXPECT RELATIVELY LTL DIURNAL VARIATION OF TEMP WITH STRG SLY FLOW...GFS SHOWS H925 WINDS UP TO 35-40 KTS. WL ISSUE GALE WRNG FOR LK SUP AS THIS LLJ MOVES OVHD TO THE S OF AREA OF SHARP PRES FALLS MOVING ACRS ONTARIO. ON THU...SHRTWV/SFC LO FCST TO SHEAR TO THE ENE...DRAGGING SFC COLD FNT TO THE E AND SCNTRL ZNS BY LATE IN THE DAY. ALTHOUGH SOME LLVL MSTR REMAINS...DRYING ALF IN JET SURGE REGION UNDER H85-5 QVECTOR DVGC SUGS ANY PCPN WL BE ON THE LGT SIDE. TEMPTED TO RESTRICT POPS TO JUST THE N AND E DURING THE MRNG BEFORE DEEPER MSTR EXITS... BUT 00Z GFS HINTS SOME UPR DVGC IN RRQ OF JET PASSING TO THE NE WL CAUSE AN AXIS OF HIER H7 RH OVER THE FNT LATER IN THE DAY OVER THE SCNTRL AND E. SINCE SEVERAL OTHER OPS MODELS ARE SLOWER PUSHING THE FNT THROUGH UNDER SW FLOW ALF PARALLEL TO SFC BNDRY...WL RETAIN AT LEAST A 20 POP OVER THE ENTIRE FA. WL ALSO INCLUDE MIX WITH RA OVER THE SCNTRL AS SFC TEMPS WL RISE WELL ABV 32 AND FCST SNDGS HINT AT SUFFICIENT DEPTH OF ABV FRZG NR SFC LYR TO JUSTIFY LIQUID PCPN. WITH RELATIVELY WARM START...THU LOOKS TO BE THE WARMEST DAY OF THE WEEK EVEN THOUGH CONSIDERABLE CLD COVER WL RESTRICT DIURNAL TEMP RISE. COLDER AIR FCST TO GRDLY FILTER BACK INTO UPR MI THU NGT/FRI AS UPR FLOW GRDLY VEERS FM SW TO MORE W WITH TIME. BUT GFS/UKMET HINT THAT RRQ OF UPR JET IN CONFLUENCE ZN BTWN NRN AND SRN BRANCHES WL REMAIN OVER THE FA WITH A POCKET OF HIER H7 RH NEAR FOCUSED H8-7 FGEN WELL TO THE N OF RELATIVELY SHALLOW ARCTIC INTRUSION. ALTHOUGH NLY FLOW OF ARCTIC AIR APPEARS TO BE RATHER DRY...WL MAINTAIN SOME CHC POPS DURING THIS TIME FOR EITHER THE FGEN FORCING OR LES POTENTIAL. CONSIDERING THE FAIRLY HI STABILITY AND SHARP H8-7 FGEN...HAVE TRENDED DOWN ON FCST TEMPS THU NGT/FRI PER GFS FCST SDNGS AND GFS/ETA MOS GUIDANCE. MUCH UNCERTAINTY REMAINS IN THE LATER PDS AS TO INTERACTION BTWN NRN BRANCH AND SRN BRANCH CLOSED LO OVER THE DESERT SW. LATEST GUIDANCE HAS TRENDED A BIT SLOWER WITH EJECTION OF THIS FEATURE...SO ADDED LO CHC POPS OVER THE SCNTRL ZNS ON SUN NGT/MON TO MATCH SURROUNDING OFFICES. COORDINATED WITH APX/GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING E HALF OF LAKE SUPERIOR. && $$ ROLFSON (UPDATE) KC (PREV DISCUSSION) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1110 AM EST WED JAN 10 2007 .UPDATE...LATEST SURFACE/RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW HIGH PRESSURE CENTERED OVER THE OHIO RIVER VALLEY WHOSE RIDGE AXIS RUNS FROM WESTERN KENTUCKY ACROSS WESTERN LAKE MICHIGAN AND CENTRAL U.P./LAKE SUPERIOR. LAKE EFFECT BANDS ARE STARTING TO SHOW SIGNS OF BACKING PER RADAR TRENDS OVER THE PAST HOUR...AS THE RIDGE AXIS APPROACHES. AFTER A VERY BRIEF FLARE UP THIS MORNING...SNOW INTENSITIES HAVE BEEN GENERALLY ON THE WANE WITH VISIBILITIES MOSTLY GREATER THAN 2SM WITH ONLY LOCALIZED AREAS OF DBZ GREATER THAN 24 ON RADAR. 12Z APX SOUNDING SHOW INVERSION HEIGHTS CONTINUE TO FALL...LOWERING TO ABOUT 830MB...DOWN FROM 750MB 12 HOURS AGO. 850MB TEMPS CONTINUE TO BE COLD AT -18C...BUT UPSTREAM SOUNDING FROM GREEN BAY SHOWS WARM ADVECTION IS STARTING TO TAKE HOLD (850MB TEMPS UP TO -12C) AND WARM ADVECTION CLOUDS HAVE BEEN MOVING ACROSS WISCONSIN. LAKE EFFECT SNOW CONTINUES TO BE THE MAIN FORECAST CONCERN FOR THE REST OF TODAY. SURFACE RIDGE AXIS WILL PASS ACROSS THE STATE THIS AFTERNOON CAUSING THE LOW LEVEL WINDS TO CONTINUE TO BACK. THEREFORE...EXPECT THE LAKE EFFECT BAND ORIENTATION TO CONTINUE ITS RECENT TREND TO WESTERLY TO MORE SOUTHWEST BY THE MIDDLE OF THE AFTERNOON. WITH THE 850MB RIDGE AXIS MOVING CLOSER AS WELL...SUBSIDENCE WILL CAUSE INVERSION HEIGHTS TO LOWER FURTHER...TO AROUND 900MB BY 00Z. ADDITIONALLY...DELTA T/S WILL DECREASE AS THE DAY WEARS ON...DROPPING TO AROUND 13C OVER NORTHERN LAKE MICHIGAN BY 00Z. THEREFORE...WITH INCREASINGLY HOSTILE LAKE EFFECT CONDITIONS...EXPECT SNOW SHOWERS TO DIMINISH AS THE DAY WEARS ON...BUT WILL STILL GO NUMEROUS FOR NORTHWEST LOWER THROUGH MID-AFTERNOON...THEN SCATTERED FOR LATE AFTERNOON RIGHT ALONG THE LAKE MICHIGAN SHORELINE AS 1000-850MB WINDS TURN TO THE SOUTHWEST. SNOW ACCUMULATIONS WILL BE MINOR...MAYBE A HALF INCH AROUND MANCELONA. WILL DROP THE LES SNOW WARNING FOR CHIPPEWA COUNTY AS SNOW HAS DIMINISHED ENOUGH TO ONLY ALLOW MINOR ACCUMULATIONS. AREAS TO THE EAST OF I-75 WILL LIKELY SEE SKIES CLEAR OUT SOMEWHAT WITH THE DIMINISHING SNOW SHOWERS AND WILL KEEP PARTLY CLOUD SKIES HERE. DO NOT EXPECT MUCH CLEARING ALONG THE LAKE MICHIGAN SHORELINE AND EASTERN UPPER WHERE ONSHORE FLOW...AND INCREASING MID-LEVEL MOISTURE FROM WARM AIR ADVECTION WILL KEEP SKIES ON THE MOSTLY CLOUDY SIDE. MARINE...WINDS HAVE STEADILY DECREASED THROUGH THE MORNING...WELL BELOW GALE FORCE OVER THE COASTAL CONVERGENT REGIME OF NORTHEAST LOWER. WILL THEREFORE DROP THE GALE WARNINGS FROM THE STRAITS TO STURGEON POINT...BUT KEEP SMALL CRAFT ADVISORIES IN THEIR OVER WHITEFISH POINT AND THE LAKE HURON SHORELINE SINCE WINDS IN THE MIX LAYER WILL APPROACH OR EXCEED 25 KNOTS. ZONES OUT SHORTLY. MPC PREVIOUS DISCUSSION...ISSUED AT 311 AM EST WED JAN 10 2007 LAKE EFFECT SNOW (LES) CONTINUES. NW FLOW ON SUPERIOR/ EASTERN UPPER MI...WNW FLOW ON LK MI/NORTHERN LOWER. HIGH PRESSURE IN AR WAS EXTENDING A RIDGE NORTHWARD INTO MN. THIS RIDGE WILL MAKE ITSELF FELT 1ST IN A LOW-LEVEL DRYING TREND FROM THE WEST THIS MORNING...AND THIS AFTERNOON IN BACKING OF THE 1000-850MB WIND HERALDING THE ONSET OF WARM ADVECTION. THUS...IN THE NEAR TERM...THE MAIN ISSUE IS ONGOING LES. AFTER THAT (LATE TONIGHT ONWARD)...MAIN CONCERN IS HOW ENERGY MOVING ACROSS SOUTHERN CANADA WILL INTERACT WITH STRONG WARM ADVECTION. MODELS...THE GFS IS FASTER AND LESS AMPLIFIED WITH A FILLING UPPER LOW THAT DEGENERATES INTO AN OPEN WAVE AS IT REACHES NORTHERN ONTARIO THURSDAY. QUITE A BIT OF UNCERTAINTY HERE...WITH THE CANADIAN FAVORING THE GFS...THE NGM THE NAM...AND THE NOGAPS OFF ON ITS OWN SOMEWHERE. BUT THE VAST MAJORITY OF SREF ENSEMBLE MEMBERS RESEMBLE THE GFS...AND THUS WILL LEAN THE FORECAST THAT WAY. TODAY...LES SHOULD DWINDLE THRU THE DAY. 850-700MB RH LEVELS... STARTING THE MORNING AT 60-70 PERCENT...WILL LOWER TO 40-50 PERCENT BY MIDDAY...AND 30 PERCENT OR LESS BY EVENING. DELTA T/S WILL HOLD NEAR 20 IN THE MORNING...THEN LOWER QUICKLY INTO THE MID TEENS. THE MOST SIGNIFICANT DECREASE WILL BE DURING THE PM HOURS...AS LES SHOULD BE ABLE TO SURVIVE THE INITIAL BIT OF DRYING...ESPECIALLY GIVEN THE CONSIDERABLE INSTABILITY PRESENT. THE CURRENT LES IN NORTHERN LOWER IS DISORGANIZED...THOUGH A FEW VIGOROUS SNOW SHOWERS ARE SEEN FROM TIME TO TIME. IT IS DIFFICULT TO SEE HEADLINE-CRITERIA ACCUMS GIVEN POOR ORGANIZATION NOW AND GRADUALLY MORE HOSTILE LES CONDITIONS DURING THE DAY. THUS WILL EXPIRE HEADLINES IN NORTHERN LOWER MI ON SCHEDULE...WITH LOCAL 1-2 INCH ACCUMS IN WNW FLOW SNOWBELTS. POPS WILL BE HIGH THRU EARLY TO MID AFTERNOON...BUT DECREASE LATE AS BACKING WINDS/WARMING TEMPS/DRYING REALLY KICKS IN. BLOWING/DRIFTING IS A MARGINAL CONCERN NOW...BUT WITH THE PRESSURE GRADIENT AND WINDS EXPECTED TO SLACKEN FURTHER BY DAWN...WILL NOT MENTION ANY OF THAT FOR THE DAYTIME HOURS. IN EASTERN UPPER...AS WE OFTEN SEE THE EASTERNMOST BAND IS GETTING SERIOUSLY ENHANCED BY LAND BREEZE CONVERGENCE FROM ONTARIO. MONTREAL RIVER RADAR HAS 30-40DBZ RETURNS WITH THIS BAND. THE BAND WAS SLOWLY GETTING PUSHED WESTWARD BY THE DRAINAGE FLOW EARLY ON. HOWEVER...THE COMBINATION OF STRONGISH NW FLOW AND MUCH WEAKER N DRAINAGE WINDS HAVE STOPPED THAT PROCESS. THE BAND STALLED OUT OVER BRIMLEY AND BAY MILLS...WHICH PICKED UP THE BETTER PART OF 8 INCHES OF SNOW BETWEEN MIDNIGHT AND 2 AM. HAVE ALREADY UPGRADED CHIP TO AN LES WARNING... WHICH IS IN EFFECT THRU NOON. LOCAL ACCUMS COULD EASILY REACH OR EXCEED A FOOT BEFORE BAND WEAKENS WITH THE INCOMING DRIER AIRMASS AFTER DAWN. TONIGHT...SURFACE RIDGE IS ALREADY HEADING EAST OF THE AREA...WITH STRONG SOUTHERLY FLOW RAPIDLY GETTING ESTABLISHED IN ITS WAKE. 850MB TEMPS WILL ROCKET UPWARD INTO THE 0 TO -5C RANGE. BOTH THE NAM AND GFS DRAPE A WARM FRONT THRU THE STRAITS REGION...AHEAD OF AN OCCLUDED SURFACE LOW ENTERING FAR WESTERN ONTARIO LATE. ASCENT NORTH OF THIS BOUNDARY MAY BE ABLE TO WRING OUT SOME SNOWFLAKES IN EASTERN UPPER MI OVERNIGHT...ESPECIALLY IF THE SLIGHTLY COOLER GFS IS NEARER THE TRUTH (850MB TEMPS NEAR -6C) WHICH WOULD KEEP LAKE MI MARGINALLY IN PLAY FOR SOME ENHANCEMENT. STILL...BOTH THE GFS AND NAM HAVE A MOISTURE DISCONNECT...WITH MOIST MID LEVELS AND DRY LOW LEVELS BY MIDNIGHT...AND THE REVERSE BY MORNING. WILL MAINTAIN A CHANCE OF LIGHT SNOW THRU THE NIGHT...DYING LES EARLY IN SOUTH FLOW...AND SYNOPTIC/MARGINALLY ENHANCED LATE. SKIES WILL BE MOSTLY CLOUDY NORTH...PARTLY CLOUDY SOUTH. MIN TEMPS WILL BE EARLY IN THE EVENING...WITH READINGS RISING SHARPLY (AROUND 10F IN SPOTS) DURING THE NIGHT. THURSDAY...LOW PRESSURE PASSES JUST NORTH OF SUPERIOR DURING THE DAY...NEARING QUEBEC BY EVENING. A TRAILING COLD FRONT WILL APPROACH EASTERN UPPER MI FROM THE NW LATE. EASTERN UPPER MI...WHERE THE MOISTURE REMAINS DEEPER BIT STILL WITH SOME DRY AIR IN THE MID LEVELS...WILL KEEP A CHANCE OF SPOTTY SNOW THRU THE DAY (MAY HAVE TO ADD SOME DRIZZLE IN LATER FORECASTS IF MID LEVEL DRYING IS MORE PRONOUNCED). IN NORTHERN LOWER MI...THE MAIN ISSUE IS THE MOISTENING OF THE SUB-800MB LAYER...WHICH LATE IN THE DAY WILL REACH DOWN TO THE SURFACE. WITH MOISTURE ONLY EXTENDING TO -5C OR SO...SHEAR (VEERING) WITHIN THE MOIST LAYER...AND THE GFS PORTRAYING A NOSE OF HIGHER MOISTURE JUST ABOVE THE 825MB INVERSION...THE SETUP APPEARS REASONABLE FOR DRIZZLE OR VERY LIGHT RAIN. TEMPS WILL RETURN (BRIEFLY) TO THE BALMY CONDITIONS OF THE LAST MONTH...WITH HIGHS FROM THE MID 30S NORTH TO LOWER 40S SOUTH. THURSDAY NIGHT/FRIDAY...WE CAN SAY WITH SOME CONFIDENCE THAT THE COLD FRONT WILL SLOWLY OOZE SOUTH THRU THE AREA THURSDAY NIGHT INTO EARLY FRIDAY...THEN SETTLE TO OUR SOUTH. WE CAN ALSO SAY THAT A WAVE (MAYBE TWO) WILL LIFT NE ALONG THIS BOUNDARY. THAT/S AS CERTAIN AS WE CAN GET AT THIS POINT. TIMING IS HIGHLY UNCERTAIN...THE FASTER GFS IS CONSEQUENTIALLY MUCH...MUCH MORE MOIST THAN THE NAM. WILL MAINTAIN AN UNCERTAIN CHANCE POP ACROSS THE FORECAST AREA...THROUGH THE BEST CHANCE WILL PROBABLY BE IN THE SOUTH LATER ON FRIDAY. THERMAL PROFILES FROM SOUNDINGS SUPPORT SNOW FOR MOST OF THE FORECAST AREA. HOWEVER...SINCE IT/S UNCERTAIN WHEN THE MID LEVELS WILL MOISTEN...DRIZZLE WILL REMAIN A DECENT POSSIBILITY IN MUCH OF NORTHERN LOWER INTO EARLY THURSDAY NIGHT AT LEAST. WILL KEEP THE FORECAST SIMPLE...AND JUST BRING THE RAIN/SNOW MIX POTENTIAL SOMEWHAT FURTHER NORTH INTO NORTHERN LOWER MI THU NIGHT/FRIDAY. NO SIGNIFICANT CHANGES TO LATER PERIODS. CONTINUED UNCERTAINTY WITH WHAT SORT OF WAVE WILL EJECT ALONG THE FRONT TO OUR SOUTH. LOOKS LIKE EARLY NEXT WEEK WILL FEATURE OUR COLDEST WEATHER SO FAR THIS WINTER. ZOLTOWSKI && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 335 AM EST WED JAN 10 2007 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW TROF OVER ERN NAMERICA DOWNSTREAM OF UPR RDG BLDG INTO THE NRN PLAINS IN ADVANCE OF POTENT SHRTWV CRASHING INTO THE PAC NW (12Z-24Z H3 HGT FALL UP TO 250M IN NW WA STATE). CWA EARLY THIS MRNG REMAINS DOMINATED BY COLD AND GUSTY LLVL NW FLOW BTWN SFC HI PRES RDG APRCHG THE MS RIVER VALLEY AND DEEP LO PRES OVER QUEBEC. H85 TEMPS UPSTREAM STILL AS LO AS -21C AT YPL. ALTHOUGH LLVLS AT THIS SITE ARE RELATIVELY MOIST...ABSOLUTE MSTR IS LIMITED WITH SFC DWPTS BLO 0F IN MN AND ONTARIO NW OF LK SUP. 00Z INL SDNG IS QUITE A BIT DRIER THAN THE YPL SDNG CLOSER TO RDG AXIS...AND SKIES ARE MOCLR NOW IN THE MN ARROWHEAD. DESPITE THE VIGOROUS CAD OVER THE UPR LKS...THE COMBINATION OF THIS DRY AIR AND LO INVRN ARND H9 AS SHOWN ON THE 00Z INL/YPL RAOBS AS WELL AS TAMDAR SDNGS AT DLH/YQT HAVE NEGATIVELY IMPACTED LES AMTS EVEN OVER THE ERN ZNS WHERE LONGER FETCH ACRS THE LK HAS ALLOWED MORE LLVL MOISTENING AND DEEPER MIXED LYR UP TO H8 AS SHOWN ON THE 00Z TAMDAR SDNG FM SAW. NO MORE THAN 3-4 INCHES OF SN HAS FALLEN THRU 04Z. FARTHER UPSTREAM...MID/HI CLD IN WAD AHEAD OF SHRTWV MOVING INTO THE PAC NW HAS SPREAD THRU THE UPR RDG INTO NW MN. 00Z BIS SDNG IS QUITE DRY BLO H8...SO LEADING EDGE OF LGT SN TRAILS WELL BEHIND IN SE SASKATCHEWAN AT 04Z. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND LES TRENDS. FOCUS THEN SHIFTS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE PAC NW WITH CHC OF -SN AS EARLY AS THIS AFTN. FOR TDAY...NUMERICAL GUIDANCE SHOWS H5 HGT RISES UP TO 120M AS RDG IN THE PLAINS CONTINUES TO BLD EWD. SFC RDG AXIS PROGGED TO REACH NR IWD AT 12Z BEFORE PUSHING E OF ANJ BY 00Z THU. AS THE RDG AXIS/LOWER INVRN HGT APRCH FM THE W...EXPECT ONGOING LES TO END AND WINDS TO DIMINISH W-E. HAVE OPTED TO EXTEND THE LES ADVY (WITHOUT THE BLSN) OVER THE E A FEW HRS TO ACCOUNT FOR FVRBL CONDITIONS FOR MORE SHSN INTO MID MRNG. OTRW...BRIEF CLRG WL GIVE WAY TO INCRSG HI/MID CLD WITH ONSET OF ISENTROPIC ASCENT AS SHOWN ON THE 280-300K SFCS. SINCE LLVLS ON THE BIS SDNG ARE SO DRY AND ISENTROPIC ASCENT APPEARS TO BE THE ONLY FORCING MECHANISM FOR UPWARD MOTION WITH DPVA/UPR DVGC ASSOCIATED WITH SHRTWV NOW MOVING INTO THE PAC NW REMAINING TO THE NW THRU 00Z (SHRTWV ITSELF FCST TO REACH SE SASKATCHEWAN AT 00Z)... HAVE OPTED TO TAKE OUT THE WAD POPS TDAY OVER THE ENTIRE CWA PER VARIOUS MOS FCSTS. RESOLVE STRENGTHENED BECAUSE ISENTROPIC LIFT APPEARS TO BE GOING MORE TOWARD HORIZONTAL TEMP ADVCTN VS UVV AS PRES FCST TO RISE STEADILY ON THE ISENTROPIC SFCS IN QUESTION (I.E. STEADY WARMING)...NOT SURPRISING CONSIDERING TRACK OF SHRTWV WELL TO THE NW. OTRW...VARIOUS MOS FCST HI TEMPS CONSISTENT WITH READINGS EXPECTED FM EXPLICIT GFS FCST SDNGS. TNGT...SHRTWV OVER SRN CANADA FCST TO MOVE INTO NW ONTARIO BY 12Z THU. THERE IS SOME DISCREPANCY WITH REGARD TO THE POSITION OF SFC LO BY 12Z...WITH NAM FARTHEST TO THE NW JUST E OF LK WINNIPEG AND UKMET FARTHEST TO THE S NR DLH. 00Z GFS/12Z ECMWF LOOK TO BE A RSNBL COMPROMISE BTWN THESE SOLNS WITH SFC LO JUST N OF INL. GFS SHOWS BEST ISENTROPIC LIFT AS WELL AS DPVA/SHARPER H85-5 QVECTOR CNVGC/UPR DVGC TO THE N. CONSIDERING THE PLACEMENT OF THESE BETTER DYNAMICS AND LINGERING DRY AIR...HAVE OPTED TO RESTRICT CHC POPS TO OVER THE NRN TIER AND DOWNWIND OF LK MI WHERE STRONG SLY FLOW WL BE ABLE TO PICK UP SOME MSTR IN LONG FETCH OVER LK. IN FACT...GFS FCST SDNG FOR ERY AT 06Z SHOWS RELATIVELY DEEP MSTR...SO HIEST CHC POPS IN THIS LOCATION. OTRW...EXPECT RELATIVELY LTL DIURNAL VARIATION OF TEMP WITH STRG SLY FLOW...GFS SHOWS H925 WINDS UP TO 35-40 KTS. WL ISSUE GALE WRNG FOR LK SUP AS THIS LLJ MOVES OVHD TO THE S OF AREA OF SHARP PRES FALLS MOVING ACRS ONTARIO. ON THU...SHRTWV/SFC LO FCST TO SHEAR TO THE ENE...DRAGGING SFC COLD FNT TO THE E AND SCNTRL ZNS BY LATE IN THE DAY. ALTHOUGH SOME LLVL MSTR REMAINS...DRYING ALF IN JET SURGE REGION UNDER H85-5 QVECTOR DVGC SUGS ANY PCPN WL BE ON THE LGT SIDE. TEMPTED TO RESTRICT POPS TO JUST THE N AND E DURING THE MRNG BEFORE DEEPER MSTR EXITS... BUT 00Z GFS HINTS SOME UPR DVGC IN RRQ OF JET PASSING TO THE NE WL CAUSE AN AXIS OF HIER H7 RH OVER THE FNT LATER IN THE DAY OVER THE SCNTRL AND E. SINCE SEVERAL OTHER OPS MODELS ARE SLOWER PUSHING THE FNT THROUGH UNDER SW FLOW ALF PARALLEL TO SFC BNDRY...WL RETAIN AT LEAST A 20 POP OVER THE ENTIRE FA. WL ALSO INCLUDE MIX WITH RA OVER THE SCNTRL AS SFC TEMPS WL RISE WELL ABV 32 AND FCST SNDGS HINT AT SUFFICIENT DEPTH OF ABV FRZG NR SFC LYR TO JUSTIFY LIQUID PCPN. WITH RELATIVELY WARM START...THU LOOKS TO BE THE WARMEST DAY OF THE WEEK EVEN THOUGH CONSIDERABLE CLD COVER WL RESTRICT DIURNAL TEMP RISE. COLDER AIR FCST TO GRDLY FILTER BACK INTO UPR MI THU NGT/FRI AS UPR FLOW GRDLY VEERS FM SW TO MORE W WITH TIME. BUT GFS/UKMET HINT THAT RRQ OF UPR JET IN CONFLUENCE ZN BTWN NRN AND SRN BRANCHES WL REMAIN OVER THE FA WITH A POCKET OF HIER H7 RH NEAR FOCUSED H8-7 FGEN WELL TO THE N OF RELATIVELY SHALLOW ARCTIC INTRUSION. ALTHOUGH NLY FLOW OF ARCTIC AIR APPEARS TO BE RATHER DRY...WL MAINTAIN SOME CHC POPS DURING THIS TIME FOR EITHER THE FGEN FORCING OR LES POTENTIAL. CONSIDERING THE FAIRLY HI STABILITY AND SHARP H8-7 FGEN...HAVE TRENDED DOWN ON FCST TEMPS THU NGT/FRI PER GFS FCST SDNGS AND GFS/ETA MOS GUIDANCE. MUCH UNCERTAINTY REMAINS IN THE LATER PDS AS TO INTERACTION BTWN NRN BRANCH AND SRN BRANCH CLOSED LO OVER THE DESERT SW. LATEST GUIDANCE HAS TRENDED A BIT SLOWER WITH EJECTION OF THIS FEATURE...SO ADDED LO CHC POPS OVER THE SCNTRL ZNS ON SUN NGT/MON TO MATCH SURROUNDING OFFICES. COORDINATED WITH APX/GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVY UNTIL 15Z WED MIZ006-007-085. GALE WRNG E 1/2 LK SUP. && $$ KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 747 PM CST THU JAN 11 2007 .DISCUSSION... UPDATED WIND CHILL ADVISORY TO SPREAD INTO A COUPLE MORE COUNTIES OVERNIGHT. TEMPERATURES ARE DROPPING QUICKLY AS SHALLOW ARCTIC AIRMASS SURGES TO THE SOUTH/EAST ALONG AND WEST OF THE MINNESOTA RIVER VALLEY. LIGHT SNOW CLIPPING THE FAR NORTHERN CWA...WITH A DUSTING TO NEAR AN INCH POSSIBLE AS WEAK SHORT WAVE MOVES/RIDES SOUTHWEST/NORTHEAST ORIENTED 25H JET MOVING ACROSS NORTHERN MN. ALONG WITH THIS FORCING...00Z RUC INDICATING BAND OF 600 MB FULL WIND FRONTOGENESIS MOVING ACROSS NORTHERN CWA THROUGH ABOUT 06Z AS WELL. UPPED THE POPS THIS REGION TO LIKELY AND ADDED LESS THAN 1 INCH ACCUMULATION POSSIBLE OVERNIGHT. APPEARS BEST CHANCE NORTH OF A LINE FROM NEAR KAXN-KLXL-KJMR. $$ .PREV DISCUSSION... /ISSUED 549 PM CST THU JAN 11 2007/ UPDATE...ADDED THE 00Z TAF DISCUSSION. PREV DISCUSSION... /ISSUED 334 PM CST THU JAN 11 2007/ DISCUSSION... COLD AIR POURING IN THIS AFTERNOON...WHICH HAS SURE BEEN SCARCE THIS SEASON. CURRENT SURFACE TEMPS UPSTREAM ARE COLDER THAN SHORT TERM MODEL TRENDS BUT LATEST RUC HAS BETTER HANDLE. MIN TEMPS SHOULD BE BELOW ZERO IN THE FAR NORTHWEST OR WEST COUNTIES. WIND CHILL VALUES WILL BE CLOSE TO CRITERIA...MAINLY LATE TONIGHT AND FRIDAY MORNING. WITH ABRUPT CHANGE...WILL GO AHEAD WITH AN ADVISORY FOR A FEW COUNTIES. WEAK WAVE STREAKING ENE ACROSS N CENTRAL SD WILL CAUSE SOME LIGHT SNOW IN FAR N CWA MAINLY THIS EVENING. OTHERWISE KIND OF IN A HOLDING PATTERN UNTIL SATURDAY NIGHT. GFS ENSEMBLE POPS OF LESS THAN 0.10 INCH KEEPING BEST CHANCES GENERALLY SOUTH OF AREA UNTIL SUNDAY OR SUNDAY NIGHT. THIS IS IS ABOUT WHAT WE CURRENTLY HAVE IN OUR GRIDS. ECMWF SHOWING A HINT OF A WEAK WAVE LIFTING OUT AHEAD OF SYSTEM LIFTING OUT ON SUNDAY WILL KEEP THE SMALL CHANCE SATURDAY NIGHT. ONCE AGAIN A SPLIT FLOW SITUATION WHICH HAS BEEN THE CASE MOST OF THE FALL AND EARLY WINTER..SO EXPECT A FAIRLY SHARP CUT OFF IN PRECIP AGAIN. LOOKS LIKE A COUPLE OF COLD NIGHTS AFTER THIS SYSTEM MOVES THROUGH..WITH MORE WIDESPREAD SUB ZERO MIN TEMPS. FAIRLY DRY NW FLOW SO SLIM CHANCE OF PRECIP...THERE IS A HINT OF A WAVE IN NW FLOW ABOUT TUESDAY OR WEDNESDAY BUT WILL LEAVE DRY FOR NOW. AVIATION...21Z RUC SHOWING SATURATION/UPGLIDE ON THE 280K THETA SURFACE ACROSS EAST CENTRAL AND SOUTH CENTRAL MN AND WEST CENTRAL WI. THIS CORRESPONDS PRETTY WELL WITH THE MVFR CEILINGS AT KMSP...KRNH AND KEAU. BELIEVE AS THE EVENING PROGRESS...KMSP WILL BREAK OUT OF THE LOW CEILINGS. BACK EDGE OF THE STRATUS LATE THIS AFTERNOON WAS PROGRESSING EAST AT 7 KNOTS. KEPT KEAU DOWN THROUGH LATE TOMORROW MORNING. TO THE WEST...MID LEVEL FRONTOGENESIS ACROSS THE CENTRAL DAKOTAS THROUGH NE MN WILL CONTINUE TO PROMOTE AN AREA OF FORCING THAT WILL SLIDE ACROSS THE NW CWA THIS EVENING. KEPT THE MENTION OF SNOW TO KAXN. INDICATED A SMALL PERIOD OF MVFR CEILINGS DURING THE EARLY MORNING HOURS AT KSTC AND KMSP AS THE ARCTIC AIR SURGES IN. BUFKIT PROFILE DATA FOR ALL OF THE MN TAF SITES INDICATES 20 TO 22 KNOT WIND GUSTS THROUGH MUCH OF THE TAF PERIOD WITH SUSTAINED WINDS NEAR 15 KNOTS. $$ && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL 12 PM CST FRIDAY FOR CHIPPEWA-DOUGLAS- LAC QUI PARLE-POPE-STEVENS-SWIFT-TODD-YELLOW MEDICINE COUNTY(IES). WI...NONE. && $$ RAH/DWE mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 549 PM CST THU JAN 11 2007 .UPDATE...ADDED THE 00Z TAF DISCUSSION. && .PREV DISCUSSION... /ISSUED 334 PM CST THU JAN 11 2007/ DISCUSSION... COLD AIR POURING IN THIS AFTERNOON...WHICH HAS SURE BEEN SCARCE THIS SEASON. CURRENT SURFACE TEMPS UPSTREAM ARE COLDER THAN SHORT TERM MODEL TRENDS BUT LATEST RUC HAS BETTER HANDLE. MIN TEMPS SHOULD BE BELOW ZERO IN THE FAR NORTHWEST OR WEST COUNTIES. WIND CHILL VALUES WILL BE CLOSE TO CRITERIA...MAINLY LATE TONIGHT AND FRIDAY MORNING. WITH ABRUPT CHANGE...WILL GO AHEAD WITH AN ADVISORY FOR A FEW COUNTIES. WEAK WAVE STREAKING ENE ACROSS N CENTRAL SD WILL CAUSE SOME LIGHT SNOW IN FAR N CWA MAINLY THIS EVENING. OTHERWISE KIND OF IN A HOLDING PATTERN UNTIL SATURDAY NIGHT. GFS ENSEMBLE POPS OF LESS THAN 0.10 INCH KEEPING BEST CHANCES GENERALLY SOUTH OF AREA UNTIL SUNDAY OR SUNDAY NIGHT. THIS IS IS ABOUT WHAT WE CURRENTLY HAVE IN OUR GRIDS. ECMWF SHOWING A HINT OF A WEAK WAVE LIFTING OUT AHEAD OF SYSTEM LIFTING OUT ON SUNDAY WILL KEEP THE SMALL CHANCE SATURDAY NIGHT. ONCE AGAIN A SPLIT FLOW SITUATION WHICH HAS BEEN THE CASE MOST OF THE FALL AND EARLY WINTER..SO EXPECT A FAIRLY SHARP CUT OFF IN PRECIP AGAIN. LOOKS LIKE A COUPLE OF COLD NIGHTS AFTER THIS SYSTEM MOVES THROUGH..WITH MORE WIDESPREAD SUB ZERO MIN TEMPS. FAIRLY DRY NW FLOW SO SLIM CHANCE OF PRECIP...THERE IS A HINT OF A WAVE IN NW FLOW ABOUT TUESDAY OR WEDNESDAY BUT WILL LEAVE DRY FOR NOW. && .AVIATION...21Z RUC SHOWING SATURATION/UPGLIDE ON THE 280K THETA SURFACE ACROSS EAST CENTRAL AND SOUTH CENTRAL MN AND WEST CENTRAL WI. THIS CORRESPONDS PRETTY WELL WITH THE MVFR CEILINGS AT KMSP...KRNH AND KEAU. BELIEVE AS THE EVENING PROGRESS...KMSP WILL BREAK OUT OF THE LOW CEILINGS. BACK EDGE OF THE STRATUS LATE THIS AFTERNOON WAS PROGRESSING EAST AT 7 KNOTS. KEPT KEAU DOWN THROUGH LATE TOMORROW MORNING. TO THE WEST...MID LEVEL FRONTOGENESIS ACROSS THE CENTRAL DAKOTAS THROUGH NE MN WILL CONTINUE TO PROMOTE AN AREA OF FORCING THAT WILL SLIDE ACROSS THE NW CWA THIS EVENING. KEPT THE MENTION OF SNOW TO KAXN. INDICATED A SMALL PERIOD OF MVFR CEILINGS DURING THE EARLY MORNING HOURS AT KSTC AND KMSP AS THE ARCTIC AIR SURGES IN. BUFKIT PROFILE DATA FOR ALL OF THE MN TAF SITES INDICATES 20 TO 22 KNOT WIND GUSTS THROUGH MUCH OF THE TAF PERIOD WITH SUSTAINED WINDS NEAR 15 KNOTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 12 PM CST FRIDAY FOR CHIPPEWA-DOUGLAS-LAC QUI PARLE-POPE-STEVENS-SWIFT COUNTY(IES). WI...NONE. && $$ JPR/RAH mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1110 AM CST THU JAN 11 2007 .AVIATION... /18Z TAF CYCLE/...DIFFICULT FORECAST CEILING WISE...WITH POCKETS OF EITHER 1-1.5KFT CEILINGS OR 10KFT CEILINGS SCATTERED THROUGH THE AREA. HAVE GENERALLY GONE WITH THE TREND OF BRINGING A BRIEF BREAK IN THE LOW CLOUDS FOLLOWED BY ADDITIONAL /AND LOWER/ STRATUS DURING THE AFTERNOON...CONTINUING INTO OVERNIGHT...AS THE BRUNT OF THE LOW LEVEL COLD ADVECTION MOVES INTO THE AREA. WINDS WILL REMAIN FROM THE NORTHWEST AT 12 TO 15 KTS...WITH HIGHER GUSTS...THROUGH THE PERIOD. BROUGHT A CHANCE OF LIGHT SNOW SHOWERS INTO AXN AFTER 00Z TONIGHT...UNDER A REGION OF Q-VECTOR CONVERGENCE...HIGHER SREF POPS...AND LOWER CONDENSATION PRESSURE DEFICITS. THE ONLY OTHER TAF SITE THAT MAY SEE SOME PRECIPITATION LATE TONIGHT IS EAU...THAT BEING OF THE FLURRY OR FREEZING DRIZZLE VARIETY...BUT CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO INCLUDE. WILL PASS ON TO ONCOMING SHIFT...HOWEVER...FOR THE 00Z ISSUANCE. && .PREV DISCUSSION... /ISSUED 936 AM CST THU JAN 11 2007/ UPDATE... COLD FRONT HAS CLEARED MUCH OF THE FORECAST AREA...SANS THE EASTERN TWO TIERS OF COUNTIES IN WEST CENTRAL WISCONSIN. MANY LOCATIONS HAVE MET THEIR DAILY HIGHS ALREADY...WITH PLENTY OF COLD AIR ADVECTION MOVING IN BEHIND THE FRONT. HOURLY TEMPERATURE GRIDS FEATURE A STEADY TO FALLING TEMPERATURE TREND...MIRRORING THE TREND IN THE 06Z MAV. CLOUD COVER IS A BIT ERRATIC...WITH A FEW AREAS OF STRATOCU IN THE WESTERN FORECAST AREA...WITH SOME SCT TO OVC MID AND HIGH CLOUDS ELSEWHERE. LARGER AREA OF STRATOCU LOCATED IN SOUTHERN CANADA AND NORTHERN MINNESOTA/NORTHWEST WISCONSIN CURRENTLY SHOULD MAKE A SOUTHWARD SPREAD AS MAIN AREA OF LOW LEVEL COLD ADVECTION MOVES SOLIDLY INTO THE FORECAST AREA...WHICH SUPPORTS THE PARTLY TO MOSTLY CLOUDY FORECAST WE HAVE OUT THERE CURRENTLY. SLIGHT CHANCE OF SNOW DURING THE LATE AFTERNOON IN THE NORTHWEST ALSO LOOKS GOOD...WITH FAIRLY HIGH POPS FEATURED ON THE 09Z SREF...AND A PRONOUNCED AREA OF 500 TO 300 MB Q-VECTOR CONVERGENCE AND LOW CONDENSATION PRESSURE DEFICITS ON THE 280K SURFACE ON THE 12Z RUC/NAM. UPDATED PRODUCTS ALREADY AVAILABLE. PREV DISCUSSION... /ISSUED 411 AM CST THU JAN 11 2007/ DISCUSSION... SFC LOW PRESSURE ALONG THE CENTRAL MN/NW WI BORDER AT 10Z. PRESSURE FALLS INDICATE IT WILL MOVE ENE THIS MORNING AND DRAG COOLER AIR INTO THE WESTERN CWA. FIRST CONCERN WILL BE TEMP TRENDS THROUGHOUT THE DAY. TEMPS ROSE ACROSS THE EAST CENTRAL AND EASTERN CWA AROUND MIDNIGHT AND HAVE HELD FAIRLY STEADY SINCE AS AXIS OF WARMEST H85 TEMPS ENTERED THE EASTERN CWA. COLDER AIR FILTERING INTO THE NORTHWEST HAS BROUGHT A DOWNWARD TREND IN TEMPS PAST FEW HOURS AND EXPECT THIS TO CONTINUE THROUGH THE MORNING. HAVE INDICATED THIS IN THE GRIDS...WITH FAIRLY STEADY TEMPS ACROSS THE EAST HALF...WITH STEADY OR FALLING ACROSS THE WEST AS LOW PRESSURE MOVING NE INTO KANSAS HELPS TIGHTEN TEMP GRADIENT AND INHIBITS COLDER AIR ACROSS NRN PLAINS FROM BLASTING IN. NEXT CONCERN WILL BE LOW PRECIP CHANCES. HAVE KEPT SLIGHT CHANCE FOR SOME DRIZZLE AND FLURRIES ACROSS THE EXTREME SE AS MOISTURE RIDES UP INTO WISCONSIN AND IOWA AND INVERTED TROUGH DEVELOPS FROM NW MO THRU CENT WI. HAVE ADDED SLIGHT CHANCE FOR LIGHT SNOW LATE THIS AFTERNOON AND EARLY THIS EVENING ACROSS THE FAR NORTHWEST CWA AS MID LEVEL TEMP GRADIENT TIGHTENS BRINGING A BAND OF FRONTOGENESIS WITH INCREASED MID LEVEL MOISTURE AND Q VECTOR DIVERGENCE. WITH LIFT IN THE SNOW GROWTH ZONE SOME LIGHT SNOW MAY REACH THE GROUND...BUT BETTER MOISTURE IS JUST OUTSIDE THE CWA. HAVE ALSO INCLUDED FLURRIES THIS EVENING ACROSS THE ENTIRE AREA AS SOUNDINGS INDICATE MOIST INVERSION WITH LOW STRATUS AND SOME SYNOPTIC LIFT. COLDER AIR IS FINALLY ABLE TO WORK ACROSS THE ENTIRE AREA TOMORROW AS SFC LOW PRES PULLS OFF INTO QUEBEC...ALLOWING BAROCLINIC ZONE TO SAG SOUTHEAST. EXPECT VERY COLD BUT DRY CONDITIONS FRIDAY INTO SATURDAY. SATURDAY THROUGH MONDAY...SEEING A SLOWING TREND IN THE MODELS WITH THE EJECTION OF SOUTHWEST U.S. UPPER LEVEL LOW. THE MODELS HAVE BEEN TO FAST WITH THE EJECTION OF PREVIOUS SOUTHWEST U.S. LOWS THIS SEASON AND AM SEEING THIS AGAIN WITH THE UPCOMING SYSTEM. CANADIAN GLOBAL MODEL LOOKS TO BE THE MOST REASONABLE AT THIS POINT WITH A SOLUTION THAT REFLECTS THE TREND THAT THE GFS AND ECMWF ARE WORKING TOWARDS. CANADIAN INDICATES THAT UPPER LOW WILL CLOSE OFF OVER KS/NE BY 12Z MONDAY AND MAKE PROGRESS ENE ACROSS IA THROUGH MONDAY. THIS WOULD SET UP PRECIPITATION THAT MAY EFFECT SOUTHERN AND SOUTHEASTERN CWA SUNDAY NIGHT INTO MONDAY MORNING. SEVERAL CONCERNS FOR THIS TIME FRAME. FIRST IS SHORTWAVE TROF MOVING IN ON THE HEELS OF MAIN UPPER LOW EARLY SUNDAY. IF THIS FEATURE COMES TO FRUITION IT MAY WORK TO KICK THE LOW OUT A BIT FURTHER NORTH THAN CURRENTLY PROGGED AND SPREAD PRECIP FURTHER INTO THE CWA. ANOTHER CONCERN IS GFS AND CANADIAN DEPICTION OF NORTHERN STREAM SHORTWAVE TROF RIDING DOWN THROUGH CENTRAL CANADA AND INTERACTING WITH MAIN UPPER LOW IN CLOSE PROXIMITY TO THE CWA. A SIMILAR SCENARIO PLAYED OUT AT THE BEGINNING OF THE MONTH. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ KAT/MDB mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 936 AM CST THU JAN 11 2007 .UPDATE... COLD FRONT HAS CLEARED MUCH OF THE FORECAST AREA...SANS THE EASTERN TWO TIERS OF COUNTIES IN WEST CENTRAL WISCONSIN. MANY LOCATIONS HAVE MET THEIR DAILY HIGHS ALREADY...WITH PLENTY OF COLD AIR ADVECTION MOVING IN BEHIND THE FRONT. HOURLY TEMPERATURE GRIDS FEATURE A STEADY TO FALLING TEMPERATURE TREND...MIRRORING THE TREND IN THE 06Z MAV. CLOUD COVER IS A BIT ERRATIC...WITH A FEW AREAS OF STRATOCU IN THE WESTERN FORECAST AREA...WITH SOME SCT TO OVC MID AND HIGH CLOUDS ELSEWHERE. LARGER AREA OF STRATOCU LOCATED IN SOUTHERN CANADA AND NORTHERN MINNESOTA/NORTHWEST WISCONSIN CURRENTLY SHOULD MAKE A SOUTHWARD SPREAD AS MAIN AREA OF LOW LEVEL COLD ADVECTION MOVES SOLIDLY INTO THE FORECAST AREA...WHICH SUPPORTS THE PARTLY TO MOSTLY CLOUDY FORECAST WE HAVE OUT THERE CURRENTLY. SLIGHT CHANCE OF SNOW DURING THE LATE AFTERNOON IN THE NORTHWEST ALSO LOOKS GOOD...WITH FAIRLY HIGH POPS FEATURED ON THE 09Z SREF...AND A PRONOUNCED AREA OF 500 TO 300 MB Q-VECTOR CONVERGENCE AND LOW CONDENSATION PRESSURE DEFICITS ON THE 280K SURFACE ON THE 12Z RUC/NAM. UPDATED PRODUCTS ALREADY AVAILABLE. && .PREV DISCUSSION... /ISSUED 411 AM CST THU JAN 11 2007/ DISCUSSION... SFC LOW PRESSURE ALONG THE CENTRAL MN/NW WI BORDER AT 10Z. PRESSURE FALLS INDICATE IT WILL MOVE ENE THIS MORNING AND DRAG COOLER AIR INTO THE WESTERN CWA. FIRST CONCERN WILL BE TEMP TRENDS THROUGHOUT THE DAY. TEMPS ROSE ACROSS THE EAST CENTRAL AND EASTERN CWA AROUND MIDNIGHT AND HAVE HELD FAIRLY STEADY SINCE AS AXIS OF WARMEST H85 TEMPS ENTERED THE EASTERN CWA. COLDER AIR FILTERING INTO THE NORTHWEST HAS BROUGHT A DOWNWARD TREND IN TEMPS PAST FEW HOURS AND EXPECT THIS TO CONTINUE THROUGH THE MORNING. HAVE INDICATED THIS IN THE GRIDS...WITH FAIRLY STEADY TEMPS ACROSS THE EAST HALF...WITH STEADY OR FALLING ACROSS THE WEST AS LOW PRESSURE MOVING NE INTO KANSAS HELPS TIGHTEN TEMP GRADIENT AND INHIBITS COLDER AIR ACROSS NRN PLAINS FROM BLASTING IN. NEXT CONCERN WILL BE LOW PRECIP CHANCES. HAVE KEPT SLIGHT CHANCE FOR SOME DRIZZLE AND FLURRIES ACROSS THE EXTREME SE AS MOISTURE RIDES UP INTO WISCONSIN AND IOWA AND INVERTED TROUGH DEVELOPS FROM NW MO THRU CENT WI. HAVE ADDED SLIGHT CHANCE FOR LIGHT SNOW LATE THIS AFTERNOON AND EARLY THIS EVENING ACROSS THE FAR NORTHWEST CWA AS MID LEVEL TEMP GRADIENT TIGHTENS BRINGING A BAND OF FRONTOGENESIS WITH INCREASED MID LEVEL MOISTURE AND Q VECTOR DIVERGENCE. WITH LIFT IN THE SNOW GROWTH ZONE SOME LIGHT SNOW MAY REACH THE GROUND...BUT BETTER MOISTURE IS JUST OUTSIDE THE CWA. HAVE ALSO INCLUDED FLURRIES THIS EVENING ACROSS THE ENTIRE AREA AS SOUNDINGS INDICATE MOIST INVERSION WITH LOW STRATUS AND SOME SYNOPTIC LIFT. COLDER AIR IS FINALLY ABLE TO WORK ACROSS THE ENTIRE AREA TOMORROW AS SFC LOW PRES PULLS OFF INTO QUEBEC...ALLOWING BAROCLINIC ZONE TO SAG SOUTHEAST. EXPECT VERY COLD BUT DRY CONDITIONS FRIDAY INTO SATURDAY. SATURDAY THROUGH MONDAY...SEEING A SLOWING TREND IN THE MODELS WITH THE EJECTION OF SOUTHWEST U.S. UPPER LEVEL LOW. THE MODELS HAVE BEEN TO FAST WITH THE EJECTION OF PREVIOUS SOUTHWEST U.S. LOWS THIS SEASON AND AM SEEING THIS AGAIN WITH THE UPCOMING SYSTEM. CANADIAN GLOBAL MODEL LOOKS TO BE THE MOST REASONABLE AT THIS POINT WITH A SOLUTION THAT REFLECTS THE TREND THAT THE GFS AND ECMWF ARE WORKING TOWARDS. CANADIAN INDICATES THAT UPPER LOW WILL CLOSE OFF OVER KS/NE BY 12Z MONDAY AND MAKE PROGRESS ENE ACROSS IA THROUGH MONDAY. THIS WOULD SET UP PRECIPITATION THAT MAY EFFECT SOUTHERN AND SOUTHEASTERN CWA SUNDAY NIGHT INTO MONDAY MORNING. SEVERAL CONCERNS FOR THIS TIME FRAME. FIRST IS SHORTWAVE TROF MOVING IN ON THE HEELS OF MAIN UPPER LOW EARLY SUNDAY. IF THIS FEATURE COMES TO FRUITION IT MAY WORK TO KICK THE LOW OUT A BIT FURTHER NORTH THAN CURRENTLY PROGGED AND SPREAD PRECIP FURTHER INTO THE CWA. ANOTHER CONCERN IS GFS AND CANADIAN DEPICTION OF NORTHERN STREAM SHORTWAVE TROF RIDING DOWN THROUGH CENTRAL CANADA AND INTERACTING WITH MAIN UPPER LOW IN CLOSE PROXIMITY TO THE CWA. A SIMILAR SCENARIO PLAYED OUT AT THE BEGINNING OF THE MONTH. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ KAT/MDB mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 925 AM EST THU JAN 11 2007 .SHORT TERM /THIS AFTERNOON/...UPDATED SURFACE HIGH PRESSURE CENTERED OVER DELMARVA AND EASTERN VA WILL CONTINUE TO DOMINATE THE WEATHER ACROSS THE CAROLINAS THROUGH THIS AFTERNOON. KEPT MAX TEMPS THIS AFTERNOON A CATEGORY BELOW THE LATEST GUIDANCE WHICH HAS BEEN RUNNING A LITTLE WARM WITH THIS AIRMASS. SOUNDING EXTRAPOLATIONS ALSO SUGGEST STAYING ON THE COOLER SIDE OF GUIDANCE UNDER NEAR FULL SUN. MID TERM /TONIGHT THROUGH SATURDAY NIGHT/... UPPER RIDGE TO DOMINATE THE MID TERM. AT THE SFC...AN EAST-WEST RIDGE AXIS WILL EXTEND ACROSS OR IN THE VICINITY OF THE ILM CWA FROM THE HIGH CENTER LOCATED OFFSHORE FROM HAT. LATE TONIGHT AND FRIDAY...MODELS SHOW A KINK IN THE SFC PRESSURE FIELD OFF THE CAROLINA COASTS...AKA INVERTED SFC TROF. SOMEWHAT WEAK BUT MAY BE ENOUGH CONVERGENCE AND MOISTURE TO PRODUCE ONSHORE MOVEMENT OF LOW LEVEL CLOUDS. MODEL TIME HEIGHT PLOTS INDICATE VERY SHALLOW MOISTURE...EXTENDING ONLY UP TO 850MB. AS A RESULT...WILL REMOVE POPS ACROSS THE ILM CWA BUT LEAVE A SMALL CHANCE OVER THE ADJACENT OFFSHORE WATERS. SFC TROF TO DISSIPATE OR WASH OUT FRIDAY NIGHT. FOR SATURDAY...WITH STATIONARY FRONTAL BNDRY JUST NW OF THE ILM CWA...CULD OBSERVE DEBRIS CLOUDINESS ACROSS THE ILM CWA FROM PCPN MOVING ALONG IT. WILL KEEP SOME TYPE OF CLOUDINESS ACROSS THE REGION FRIDAY NIGHT THRU SAT NIGHT...BUT REMAIN PCPN FREE. TEMPS WILL DEPEND ON THE AMOUNT OF CLOUDINESS AND ONSHORE WINDS. OVERALL...WILL INDICATE A WARMING TREND WITH WIDESPREAD 70S LIKELY ON SATURDAY. JUST ANOTHER SUMMER...I MEAN WINTER WEEKEND SHAPING UP FOR THE ILM CWA. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... SUNDAY WILL BE NEARLY ANOTHER REPEAT OF SATURDAY...WITH WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS DUE TO UPPER LEVEL RIDGING AND HIGH PRESSURE AT THE SURFACE WELL OFFSHORE. AN UPPER LEVEL TROUGH MOVING ACROSS THE SOUTHERN GREAT LAKES REGION AND AN ASSOCIATED SURFACE LOW MOVING INTO WESTERN NEW ENGLAND WILL ALLOW A COLD FRONT TO SWEEP ACROSS THE AREA ON MONDAY. THIS WILL RESULT IN A SMALL CHANCE OF SHOWERS MONDAY INTO MONDAY NIGHT. ALTHOUGH THE FRONT SHOULD BE OFFSHORE ON TUESDAY...THERE IS A SLIGHT CHANCE THAT SHOWERS COULD DEVELOP BEHIND THE FRONT AND AFFECT THE AREA. AN UNUSUALLY STRONG 1050 MB HIGH OVER THE CENTRAL PLAINS WILL BUILD OVER THE AREA LATE TUESDAY...AND PERSIST THROUGH WEDNESDAY. THIS WILL CAUSE 850 MB TEMPERATURES TO PLUMMET...FALLING TO AS LOW AS -10 CELSIUS BY WEDNESDAY IF THE LATEST GFS IS CORRECT. MEANWHILE...A WAVE OF LOW PRESSURE IS EXPECTED TO DEVELOP WELL OFFSHORE ALONG THE OLD FRONTAL BOUNDARY. THIS LOW COULD BRING SOME MOISTURE BACK INTO COASTAL AREAS SO WILL CARRY A SLIGHT CHANCE OF SHOWERS FOR THESE LOCATIONS AS A RESULT. IF THE LOW AND/OR ASSOCIATED MOISTURE ARE ANY CLOSER TO THE COAST...PRECIPITATION TYPE ISSUES COULD BE A CONCERN...ESPECIALLY FOR INLAND LOCATIONS TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION... VFR EXPECTED THROUGH THE TAF FORECAST PERIOD. HIGH PRESSURE SHIFTS EAST...ALLOWING NORTHEAST WINDS TO SHIFT TO SOUTHEAST BY LATE AFTERNOON. DID NOT PUT ANY FOG IN THE TAFS FOR THE OVERNIGHT HOURS...BUT WOULD NOT BE SURPRISED TO SEE 5-6 SM BR RIGHT AT SUNRISE WITH FAIRLY LIGHT WINDS ABOVE THE BOUNDARY LAYER. && .MARINE... SHORT TERM /THIS AFTERNOON/...UPDATED PLAN TO FOLLOW THE RUC THROUGH THE AFTERNOON. THIS SCENARIO HOLDS ONTO NORTHEASTERLY FLOW VERSUS VEERING IT DIRECTLY ONSHORE AS SOME OF THE OTHER SHORT RANGE MODELS INDICATE. FEEL WITH HIGH PRESSURE RIDGING IN FROM THE NORTH AND DEVELOPMENT OF A WEAK COASTAL TROUGH THAT THE RUC HAS A GOOD HANDLE ON THE SITUATION. OTHERWISE...NO MAJOR CHANGES WITH THE MORNING UPDATE. MID TERM /TONIGHT THROUGH SATURDAY NIGHT/... UPPER RIDGE AND ITS SFC COUNTERPART TO DOMINATE THE WX AND OCEAN CONDITIONS DURING THE MID TERM. THE CENTER OF THE SFC HIGH WILL DRIFT OFFSHORE FROM CAPE HATTERAS BY LATE FRIDAY. AM NOT ALL THAT CONFIDENT WITH THE IDEA AND SOLUTION FROM VARIOUS MODELS WITH REGARDS TO THE SHALLOW SFC COASTAL TROF AND ITS POSSIBLE MOVEMENT WESTWARD. FOR NOW HAVE INDICATED A LONGER PERIOD OF NE-E WINDS ON FRIDAY WITH VEERING TO SE AND S DIRECTIONS THERE-AFTER. UNLIKE THE NAM...THE GFS WANTS TO SUPPRESS THE SFC HIGH SOMEWHAT...RESULTING IN THE EAST TO WEST SFC RDG AXIS EXTENDING SOUTH OF THE ILM WATERS. THIS TO CAUSE A WESTERLY COMPONENT IN THE WINDS. WILL HOLD OFF WITH THE SW-W WINDS UNTIL MODEL TREND/CONSISTENCY BECOMES MORE PREVALENT. OVERALL...WIND SPEEDS 15 KT OR LESS. SEAS 4 FT OR LESS. LONG TERM /SUNDAY THROUGH MONDAY/... HIGH PRESSURE WILL REMAIN WELL OFFSHORE ON SUNDAY...WITH A SOUTHERLY FLOW PERSISTING ACROSS THE COASTAL WATERS. WINDS SHOULD INCREASE ON SUNDAY NIGHT AND MONDAY AHEAD OF AN APPROACHING COLD FRONT. SEAS COULD APPROACH SMALL CRAFT ADVISORY CRITERIA DUE TO THE STRENGTHENING SOUTHERLY FLOW AND GOOD FETCH ACROSS THE COASTAL WATERS. WINDS SHOULD SHIFT OFFSHORE LATE MONDAY AS THE COLD FRONT MOVES OFFSHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...NONE. SC...NONE. MARINE...NONE. && $$ SHORT TERM...PFAFF AVIATION...DL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1033 AM CST THU JAN 11 2007 .UPDATE... NO CHANGES WERE MADE TO THE GRIDS. THE MAIN CONCERN IN THE FIRST PERIOD ARE THE GUSTY SOUTHERLY WINDS... AS THE FORECAST AREA REMAINS IN THE WARM SECTOR. A FEW LOCATIONS ACROSS WESTCENTRAL AND NORTHCENTRAL OKLAHOMA HAD INCREASED TO NEAR WIND ADVISORY CRITERIA. HOWEVER... LATEST RUC SUGGEST A WEAKENING IN THE PRESSURE GRADIENT AS THE SURFACE LOW MOVES ACROSS CENTRAL KANSAS. AS A RESULT... THE WINDS ARE EXPECTED TO WEAKEN SLIGHTLY AND STAY BELOW ADVISORY LEVELS. && .SHORT TERM... .LONG TERM... && .PREV DISCUSSION... /ISSUED 552 AM CST THU JAN 11 2007/ DISCUSSION...THE IMPENDING WINTER STORM HAS BEEN WELL ADVERTISED...BUT CHOSE TO RAMP UP TO A WINTER STORM WATCH AS SOME OF THE MESOSCALE DETAILS ARE BECOMING BETTER DEFINED. A FEW CYCLES AGO...THE MODELS TRENDED TOWARD A CLOSED UPPER LOW IN THE BASE OF THE WESTERN TROUGH...AND THIS HAS NOT CHANGED. THE UPPER LOW WAS LOCATED NEAR SEATTLE THIS MORNING AND SATELLITE SHOWED IT DROPPING ALMOST DUE SOUTH ALONG THE WEST COAST...WITH A COMPACT JET DIVING INTO THE BASE OF THE TROUGH. UPPER AIR ANALYSIS AT 00Z INDICATED STRONG COLD ADVECTION INTO THE BASE OF THE 700-500 MB TROUGH AT 00Z...AND MODELS ARE VERY SIMILAR IN TAKING THE CLOSED LOW TOWARD NORTHERN ARIZONA BY SATURDAY MORNING. A SIGNIFICANT CHANGE IN THE MODELS...HOWEVER...HAS BEEN TO DRAMATICALLY SPEED THE ARRIVAL OF SUB FREEZING TEMPERATURES ON FRIDAY. THIS HAD BEEN ANTICIPATED...BUT NOW IS APPEARING ALMOST A SURE THING AS THE LEADING EDGE OF CANADIAN AIR WAS ALREADY INTO NORTHEAST COLORADO AND SOUTHERN NEBRASKA EARLY THIS MORNING. EXPECT THE FRONT TO REACH NORTHERN OKLAHOMA BY EVENING AND I-44 AND BEYOND BY FRIDAY MORNING. THE MODELS MAY STILL NOT BE FAST ENOUGH...BUT THEY ARE STARTING TO CATCH ON. AND IN THE LATTER HALF OF THE WEEKEND THE NAM WAS PREFERRED AS IT KEEPS THE COLD AIR IN PLACE AND HAS A MORE REALISTIC PRESSURE PATTERN...NOT ALLOWING ANY STRONG CYCLOGENESIS OR SURFACE TROUGHS TO OCCUR IN THE COLD AIR AS THE GFS HAS BEEN DOING. BOTH THE NAM AND GFS PRODUCE A LOT OF LIQUID PRECIP WHICH COINCIDES WITH SUB FREEZING TEMPERATURES AT THE SURFACE. CONFIDENCE IS INCREASING TOWARD A MAJOR ICE STORM TO AFFECT THE REGION...WITH EVERYONE SEEING AT LEAST SOME FREEZING DRIZZLE AND FREEZING RAIN...BUT WITH SOME AREAS SEEING MUCH MORE. THE HEAVIER ICE ACCUMULATIONS APPEAR MOST LIKELY ALONG AND EITHER SIDE OF INTERSTATE 44...AFFECTING THE METRO AREAS FROM WICHITA FALLS TO LAWTON TO OKLAHOMA CITY...AND INCLUDING SOUTHERN OKLAHOMA. EXPECTING THE HEAVIER PRECIP TO COME IN TWO WAVES...THE FIRST ON FRIDAY INTO FRIDAY NIGHT WITH A SUB TROPICAL JET EJECTING OUT OF NORTHERN MEXICO. THIS WILL LEAD TO AN EXTENSIVE PERIOD OF ENHANCED WARM ADVECTION ALOFT IN THE RIGHT REAR OF THE JET. THE SECOND EVENT WILL COVER A LARGER AREA AS THE MAIN UPPER WAVE EJECTS FROM THE ROCKIES. THROUGHOUT ALL THIS...THERE WILL BE DEEPER MOISTURE AND POTENTIAL FOR CONVECTIVE ENHANCEMENT ALONG THE RED RIVER UP THROUGH CENTRAL OKLAHOMA. TEMPERATURES WILL BE CLOSER TO FREEZING ALONG THE RED RIVER IN SOUTHERN OKLAHOMA...BUT MUCH COLDER TOWARD WESTERN NORTH TEXAS AND CENTRAL OKLAHOMA. WILL HOPE THAT THE HEAVIEST AMOUNTS END UP NEAR OR SOUTH OF THE FREEZING LINE...BUT IF A WORST CASE SCENARIO WERE TO OCCUR THERE COULD BE A SWATH OF ICE ACCUMULATION MEASURED IN INCHES. IN ADDITION...WINDS WILL BECOME GUSTY ON SUNDAY...AND COULD BRING DOWN TREE LIMBS AND POWER LINES WEIGHTED DOWN BY THE ICE. NO CHANGES MADE BEYOND SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 63 40 40 22 / 10 40 70 70 HOBART OK 70 41 41 22 / 10 20 40 50 WICHITA FALLS TX 71 59 59 26 / 10 30 80 80 GAGE OK 66 28 28 17 / 0 10 30 40 PONCA CITY OK 59 35 35 19 / 10 30 50 50 DURANT OK 60 60 62 34 / 20 40 80 80 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR OKZ004>047-050-051. TX...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR TXZ083>090. && $$ 67/23 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 429 AM CST WED JAN 10 2007 .DISCUSSION...FORECAST FOCUSES ENTIRELY ON THE UPPER LEVEL SYSTEM AND LOW LEVEL ARCTIC AIR MASS THAT WILL BOTH DROP FROM ALASKA INTO THE WESTERN AND CENTRAL STATES. THE UPPER LOW WAS ALREADY ENCROACHING ON THE INTERNATIONAL BORDER...WITH STRONG JET FLOW OVER THE MOUNTAINS OF MONTANA CREATING A DEEP 992 MB SURFACE LOW. WITH THE LEE TROUGH EXTENDING DOWN INTO WESTERN OKLAHOMA TODAY...AND HIGH PRESSURE SITUATED OVER THE LOWER MISSISSIPPI VALLEY...A WIND ADVISORY WILL BE ISSUED FOR WESTERN AND NORTHERN OKLAHOMA. THE NAM GRIDDED DATA AND GFS MOS HAVE BEEN CONSISTENT IN SHOWING SUSTAINED WINDS NEAR 30 KNOTS IN THE TYPICALLY WINDY CORRIDORS THIS AFTERNOON...AND THE RUC IS SUPPORTING THIS TREND. IT WILL BE A WINDY BUT MILD DAY EVEN OUTSIDE OF THE ADVISORY AREA. OTHERWISE...MOST EFFORT THIS MORNING WAS PUT INTO THE PRECIPITATION FORECAST FOR THE WEEKEND. PREVIOUS THINKING CONTINUES TO BE ON TRACK...AS THE LONG RANGE MODELS STILL BRING THE FRONT THROUGH ON FRIDAY. THEY HAVE ALSO TRENDED TOWARD MAINTAINING A CLOSED LOW IN THE BASE OF THE UPPER TROUGH AS IT TURNS EAST AROUND THE FOUR CORNERS REGION. THIS TREND HAS INCREASED CONFIDENCE IN THERE BEING DEEP BROAD SCALE LIFT FROM SATURDAY INTO SUNDAY...AND POPS WERE RAISED ACCORDINGLY. POPS WERE ALSO RAISED SOMEWHAT ON THURSDAY NIGHT...WHERE MODELS ARE BETTER RESOLVING A SHARP MID LEVEL JET EJECTING FROM BAJA. THERE WILL BE A MID LEVEL DRY LAYER TO OVERCOME...BUT GFS AND NAM CROSS SECTIONS SHOW SUFFICIENT LIFT...ESPECIALLY NEAR AND SOUTH OF I-44. ALL OF THIS PRECIP WILL BE LIQUID...AS THE FRONT IS NOT DUE TO ARRIVE UNTIL EARLY FRIDAY MORNING. FROM FRIDAY INTO FRIDAY NIGHT THE AREA MAY BE UNDER SHORTWAVE RIDGING ALOFT...SO THE POTENTIAL FOR HEAVY PRECIP DOES NOT APPEAR LIKELY. BUT WITH THE FRONT SWEEPING THROUGH WE MAY SEE WIDESPREAD SHALLOW RAIN SHOWERS OR A FEW WEAK THUNDERSTORMS...MAINLY IN SOUTHERN ZONES. FARTHER NORTH...WEAK WARM ADVECTION AND UPSLOPE FLOW IS LIKELY TO GENERATE DRIZZLE AND FREEZING DRIZZLE. CURRENT THINKING IS THAT THE FRIDAY ACTIVITY MAY LEAD TO ISSUANCE OF A WINTER WEATHER ADVISORY SOMEWHERE NORTH AND WEST FROM I-44. THE PERIOD OF GREATER CONCERN FOR SIGNIFICANT ICING IS SATURDAY INTO EARLY SUNDAY. THE MAIN QUESTION IS THE POSITION OF THE FRONTAL ZONE AND THE FREEZING TEMPERATURES. EVERY LONG RANGE MODEL CONTINUES TO LOOK UNREALISTIC IN ITS DEPICTION OF AN EAST TO WEST ORIENTED FRONT THAT LIFTS NORTH ON SATURDAY. BASED ON EXPERIENCE WITH SHALLOW FRIGID AIR MASSES...EXPECT THE FRONT TO GO FARTHER SOUTH ON THE HIGH PLAINS THROUGH TEXAS AND EASTERN NEW MEXICO...BUT THE EASTERN PORTION OF THE FRONT MAY VERY WELL STALL IN SOUTHEAST OKLAHOMA...MAKING FOR SOME EXTREME TEMPERATURE DIFFERENCES ACROSS THE STATE ON SATURDAY. AS THE WARM ADVECTION CONTINUES ALOFT...WIDESPREAD DRIZZLE/LIGHT RAIN APPEAR LIKELY. TOO EARLY TO TELL WHERE THE HEAVIEST ICING MAY OCCUR...BUT THIS MAY WARRANT A WINTER STORM WATCH AS WE APPROACH THE EVENT ON THURSDAY OR FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 58 47 62 45 / 0 0 20 40 HOBART OK 62 48 64 42 / 0 0 10 20 WICHITA FALLS TX 65 49 64 53 / 0 0 10 40 GAGE OK 63 40 62 29 / 0 0 0 10 PONCA CITY OK 57 44 57 38 / 0 0 10 30 DURANT OK 60 47 62 58 / 0 10 30 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM CST THIS AFTERNOON FOR OKZ004-OKZ005-OKZ006-OKZ007-OKZ008-OKZ009-OKZ010-OKZ011- OKZ012-OKZ013-OKZ014-OKZ015-OKZ016-OKZ017-OKZ018-OKZ021- OKZ022-OKZ023-OKZ024-OKZ035. TX...NONE. && $$ BURKE/02 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 1153 PM CST WED JAN 10 2007 .AVIATION... MAIN PROBLEM CONCERNS THE DEVELOPMENT OF THE LOW CLOUD DECK. THE MODEL GUIDANCE LINED UP WITH THE CURRENT OBSERVATIONS FAIRLY WELL...MOS GUIDANCE WAS OKAY ON A SCALE OF NOT GOOD...OKAY...AND GOOD. LIKED HOW THE RUC...NAM12...AND GFS ALL LINED UP THE BEST LOW-LEVEL MOISTURE OVER THE EASTERN AND WESTERN COUNTIES EARLY... THEN FILLED IN THE CENTRAL AREAS LATER TONIGHT. THUS...EXPECT MVFR CEILINGS TO DEVELOP BETWEEN 08Z AND 10Z OVER MOST OF THE SITES FROM HOU NORTH TO UTS AND WEST TO CLL. SGR AND LBX MAY LAG AN HOUR TO 11Z AND GLS TO 14Z. THE CONFIDENCE LEVEL IS GOOD OVER THE INLAND SITES NORTH OF INTERSTATE 10 AND THE TWO BIG AIRPORTS IN HOUSTON. THURSDAY LOOKS TO BE A DIFFICULT DAY. THE MODEL GUIDANCE WAS SUGGESTING SOME BRIEF VFR BREAKS DURING THE AFTERNOON AS THE SURFACE WINDS PICK UP. THE MAV GUIDANCE LOOKS REASONABLE IN BRINGING IN SEA FOG AT GLS DURING THE EVENING. && .PREV DISCUSSION... /ISSUED 827 PM CST WED JAN 10 2007/ UPDATE... CLOUDS INCREASING A BIT FASTER THAN PROGGED. SATELLITE DERIVED PW SHOWS MOISTURE INCREASING FROM THE GULF AND THIS SHOWS UP WELL IN THE 11-3.9 SATELLITE IMAGERY. THINK MIN TEMP FORECAST IS OK...BUT WILL WATCH CLOUD TRENDS AND IF AN OVERCAST DEVELOPS...WILL LIKELY RAISE MIN TEMPS A FEW DEGREES. WILL UPDATE ZONES TO TWEAK SKY COVER OTHERWISE NO CHANGES. && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 66 52 67 62 73 / 0 0 10 20 40 HOUSTON (IAH) 66 51 69 61 73 / 0 0 10 10 20 GALVESTON (GLS) 63 57 69 62 71 / 0 0 10 10 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...43 AVIATION/MARINE...40 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1035 PM CST WED JAN 10 2007 .AVIATION... NO MAJOR CHANGES TO PREVIOUS THINKING. STRATUS HAS BEEN SLOWER TO DEVELOP THAN PREVIOUSLY FORECAST. CURRENT THINKING HAS MVFR CIGS DEVELOPING BY 08Z FOR ACT AND 09Z FOR THE METROPLEX SITES. CIGS MAY DROP AS LOW AS IFR TOMORROW MORNING...AND WILL CONTINUE TO REMAIN IN THE MVFR CATEGORY THRU THE DAY. RAIN CHANCES STILL LOOK BEST BEYOND THIS TAF CYCLE. /13 && .UPDATE... 935 PM CST WED JAN 10 2007 MINOR UPDATES TO TRENDS TONIGHT AND TO RAISE LOWS IN URBAN AREAS... AND LOWER THEM IN THE EAST A FEW DEGREES...AS LOW CLOUD COVER PER RUC/NAM LOOK TO BE IN LINE WITH MOST STRATUS SLOW TO FORM THROUGH 06Z...BUT SHOULD SURGE QUICKLY AFTERWARDS. THUS WE`LL CONTINUE TO SEE TEMPS SLOWLY DROP ACROSS MOST AREAS...THEN REMAIN STEADY OR EVEN RISE SLIGHTLY TOWARD MORNING WITH THE STRATUS AND STRONG S/SELY WNDS. ALSO ADJUSTED MSTR/RH/DEW PTS. UPDATES OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 505 PM CST WED JAN 10 2007/ AVIATION... MAIN CHALLENGE FOR THE TAFS WILL BE THE LOW CLOUDS WHICH WILL START TO DEVELOP OVERNIGHT. 40-45 KT LOW LEVEL JET WILL HELP ATMOSPHERE QUICKLY SATURATE. EXPECT MVFR CIGS TO BE PREDOMINANT...ALTHOUGH IFR CIGS WILL BE POSSIBLE. CIGS WILL NOT IMPROVE MUCH WITH DAYBREAK AND AGAIN EXPECT OVC MVFR THRU THE DAY. SOUTHERLY WINDS WILL CONTINUE... WITH SPEEDS DROPPING OFF ONLY SLIGHTLY THIS EVENING AND INCREASING AGAIN BY TOMORROW AFTERNOON. BEST RAIN CHANCES LOOK TO BE BEYOND THIS TAF SET. /13 DISCUSSION... 323 PM CST WED JAN 10 2007 SOUTH WINDS HAVE QUICKLY RETURNED TO THE AREA WITH A LARGE REGION OF 4-6 MB 3 HOUR PRESSURE FALLS ACROSS THE ENTIRE CENTRAL PART OF THE COUNTRY. THESE WINDS WILL USHER IN GULF MOISTURE IN THE OVERNIGHT HOURS...ALLOWING FOR RAPID SATURATION OF THE LOW LEVELS. CLOUDY SKIES WILL PREVAIL BY SUNRISE AS LOW CLOUDS MOVE IN FROM THE SOUTH AND HIGH AND MID LEVEL PACIFIC MOISTURE STREAMS IN FROM THE SOUTHWEST. MOISTURE BECOMES DEEP ENOUGH FOR STREAMER SHOWERS WITHIN WARM ADVECTION ZONE OF THE LOW LEVEL JET BY THURSDAY NIGHT. BETTER CHANCES OF RAIN WILL BEGIN ON FRIDAY AS CAP ERODES AND MOIST/UNSTABLE ENVIRONMENT IS IN PLACE. SUBTLE LIFTING IS EVIDENT ON THE COMPUTER MODELS...BUT UPPER TROUGH WILL BE FAIRLY FAR AWAY AND WENT WITH THE DRIER NAM SOLUTION FRIDAY. STILL DO EXPECT SCATTERED CONVECTION...BUT WILL NOT BUY INTO THE LIKELY POPS ADVERTISED BY THE MAV MOS UNTIL LATE FRIDAY NIGHT. MEANWHILE...ARCTIC AIRMASS IS NOW BEGINNING TO NOSE INTO MONTANA BEHIND POWERFUL SURFACE LOW IN SOUTH DAKOTA. 1050 MB ARCTIC HIGH WILL BUILD SOUTH INTO THE NORTHERN PLAINS BY FRIDAY MORNING WITH SINGLE DIGIT TEMPERATURES AS FAR SOUTH AS NEBRASKA. UPPER LEVEL TROUGH WILL ALSO DIG SOUTH ACROSS THE WEST COAST WHICH IS THE PRIMARY CULPRIT FOR FRONTAL TIMING UNCERTAINTIES AND FREEZING RAIN CHANCES OVER THE NW CWA. SOUTHWEST FLOW AROUND THE UPPER TROUGH WILL TRY TO HOLD THE FRONT BACK...BUT THIS AIRMASS WILL BE EXTRAORDINARILY DENSE...AND A SHALLOW 50-100 MB DEEP LAYER OF ARCTIC AIR WILL SPILL SOUTHWARD INTO OKLAHOMA BY FRIDAY. A GOOD ANALOGY TO THIS PROCESS WOULD BE LIKE POURING WATER ON A TABLE WITH THE WATER SPREADING OUTWARDS. THE NAM MODEL TYPICALLY DOES A BETTER JOB WITH SHALLOW ARCTIC AIRMASSES...AND HAS THE FRONT MOVING THOUGH FASTER/STRONGER THAN THE OTHER MODELS. SEE NO REASON NOT TO FOLLOW THE NAM FORECAST CLOSELY GIVEN ITS TRACK RECORD. WE EXPECT THE FRONT TO REACH THE NW CWA FRIDAY EVENING AND GRADUALLY MARCH SOUTH SATURDAY. WE HAVE THE FRONT CROSSING THE METROPLEX AT 9 AM SATURDAY...WACO AT 7 PM...AND FINALLY CLEARING THE SE ZONES BY 3 AM SUNDAY. POST FRONTAL RAIN/FOG/DRIZZLE WILL BE FAIRLY WIDESPREAD AS ISENTROPIC LIFT ENSUES WITH 40-50 KT SOUTHERLY LOW LEVEL FLOW ABOVE THE FRONT REMAINING INTACT. FREEZING TEMPS ARE EXPECTED TO MOVE INTO THE NW CWA BY SATURDAY EVENING AND REACH A PARIS TO DALLAS TO COMANCHE LINE BY SUNDAY MORNING. ANY LINGERING PRECIP WOULD FALL AS FREEZING RAIN. IT IS STILL TOO EARLY TO ANTICIPATE POSSIBLE ACCUMULATION OR IMPACTS...AND ANY SLIGHT DEVIATION IN THE FORECAST TEMPS WOULD GREATLY AFFECT THE ICE POTENTIAL. THE PRECIPITATION SHOULD FINALLY EXIT FROM WEST TO EAST DURING THE DAY SUNDAY WITH GENERALLY PARTLY CLOUDY AND DRY CONDITIONS EXPECTED INTO THE MIDDLE OF NEXT WEEK. IT WILL BE COLD...AND STAY RATHER CHILLY THROUGH WEDNESDAY. TEMPERATURES AROUND 20 FOR LOWS AND THE MIDDLE TO UPPER 30S FOR HIGHS APPEAR REASONABLE GIVEN THE SLOWLY MODIFYING LOW LEVEL THICKNESSES. WENT JUST A LITTLE COLDER THAN 12Z MEX MOS FOR LOWS...BUT 5-10 DEGREES COLDER FOR THE HIGHS. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 51 65 60 68 55 / 10 10 30 40 80 WACO, TX 53 66 61 70 62 / 10 10 30 40 40 PARIS, TX 45 59 58 66 57 / 10 10 30 40 80 DENTON, TX 50 64 58 67 48 / 10 10 30 40 80 MCKINNEY, TX 50 63 59 67 53 / 10 10 30 40 80 DALLAS, TX 52 65 61 69 58 / 10 10 30 40 80 TERRELL, TX 49 63 60 69 60 / 10 10 30 40 80 CORSICANA, TX 51 64 62 70 62 / 10 10 30 40 60 TEMPLE, TX 52 66 62 71 62 / 10 10 30 40 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/13/92 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 935 PM CST WED JAN 10 2007 .UPDATE... MINOR UPDATES TO TRENDS TONIGHT AND TO RAISE LOWS IN URBAN AREAS... AND LOWER THEM IN THE EAST A FEW DEGREES...AS LOW CLOUD COVER PER RUC/NAM LOOK TO BE INLINE WITH MOST STRATUS SLOW TO FORM THROUGH 06Z...BUT SHOULD SURGE QUICKLY AFTERWARDS. THUS WE`LL CONTINUE TO SEE TEMPS SLOWLY DROP ACROSS MOST AREAS...THEN REMAIN STEADY OR EVEN RISE SLIGHTLY TOWARD MORNING WITH THE STRATUS AND STRONG S/SELY WNDS. ALSO ADJUSTED MSTR/RH/DEW PTS. UPDATES OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 505 PM CST WED JAN 10 2007/ AVIATION... MAIN CHALLENGE FOR THE TAFS WILL BE THE LOW CLOUDS WHICH WILL START TO DEVELOP OVERNIGHT. 40-45 KT LOW LEVEL JET WILL HELP ATMOSPHERE QUICKLY SATURATE. EXPECT MVFR CIGS TO BE PREDOMINANT...ALTHOUGH IFR CIGS WILL BE POSSIBLE. CIGS WILL NOT IMPROVE MUCH WITH DAYBREAK AND AGAIN EXPECT OVC MVFR THRU THE DAY. SOUTHERLY WINDS WILL CONTINUE... WITH SPEEDS DROPPING OFF ONLY SLIGHTLY THIS EVENING AND INCREASING AGAIN BY TOMORROW AFTERNOON. BEST RAIN CHANCES LOOK TO BE BEYOND THIS TAF SET. /13 DISCUSSION... 323 PM CST WED JAN 10 2007 SOUTH WINDS HAVE QUICKLY RETURNED TO THE AREA WITH A LARGE REGION OF 4-6 MB 3 HOUR PRESSURE FALLS ACROSS THE ENTIRE CENTRAL PART OF THE COUNTRY. THESE WINDS WILL USHER IN GULF MOISTURE IN THE OVERNIGHT HOURS...ALLOWING FOR RAPID SATURATION OF THE LOW LEVELS. CLOUDY SKIES WILL PREVAIL BY SUNRISE AS LOW CLOUDS MOVE IN FROM THE SOUTH AND HIGH AND MID LEVEL PACIFIC MOISTURE STREAMS IN FROM THE SOUTHWEST. MOISTURE BECOMES DEEP ENOUGH FOR STREAMER SHOWERS WITHIN WARM ADVECTION ZONE OF THE LOW LEVEL JET BY THURSDAY NIGHT. BETTER CHANCES OF RAIN WILL BEGIN ON FRIDAY AS CAP ERODES AND MOIST/UNSTABLE ENVIRONMENT IS IN PLACE. SUBTLE LIFTING IS EVIDENT ON THE COMPUTER MODELS...BUT UPPER TROUGH WILL BE FAIRLY FAR AWAY AND WENT WITH THE DRIER NAM SOLUTION FRIDAY. STILL DO EXPECT SCATTERED CONVECTION...BUT WILL NOT BUY INTO THE LIKELY POPS ADVERTISED BY THE MAV MOS UNTIL LATE FRIDAY NIGHT. MEANWHILE...ARCTIC AIRMASS IS NOW BEGINNING TO NOSE INTO MONTANA BEHIND POWERFUL SURFACE LOW IN SOUTH DAKOTA. 1050 MB ARCTIC HIGH WILL BUILD SOUTH INTO THE NORTHERN PLAINS BY FRIDAY MORNING WITH SINGLE DIGIT TEMPERATURES AS FAR SOUTH AS NEBRASKA. UPPER LEVEL TROUGH WILL ALSO DIG SOUTH ACROSS THE WEST COAST WHICH IS THE PRIMARY CULPRIT FOR FRONTAL TIMING UNCERTAINTIES AND FREEZING RAIN CHANCES OVER THE NW CWA. SOUTHWEST FLOW AROUND THE UPPER TROUGH WILL TRY TO HOLD THE FRONT BACK...BUT THIS AIRMASS WILL BE EXTRAORDINARILY DENSE...AND A SHALLOW 50-100 MB DEEP LAYER OF ARCTIC AIR WILL SPILL SOUTHWARD INTO OKLAHOMA BY FRIDAY. A GOOD ANALOGY TO THIS PROCESS WOULD BE LIKE POURING WATER ON A TABLE WITH THE WATER SPREADING OUTWARDS. THE NAM MODEL TYPICALLY DOES A BETTER JOB WITH SHALLOW ARCTIC AIRMASSES...AND HAS THE FRONT MOVING THOUGH FASTER/STRONGER THAN THE OTHER MODELS. SEE NO REASON NOT TO FOLLOW THE NAM FORECAST CLOSELY GIVEN ITS TRACK RECORD. WE EXPECT THE FRONT TO REACH THE NW CWA FRIDAY EVENING AND GRADUALLY MARCH SOUTH SATURDAY. WE HAVE THE FRONT CROSSING THE METROPLEX AT 9 AM SATURDAY...WACO AT 7 PM...AND FINALLY CLEARING THE SE ZONES BY 3 AM SUNDAY. POST FRONTAL RAIN/FOG/DRIZZLE WILL BE FAIRLY WIDESPREAD AS ISENTROPIC LIFT ENSUES WITH 40-50 KT SOUTHERLY LOW LEVEL FLOW ABOVE THE FRONT REMAINING INTACT. FREEZING TEMPS ARE EXPECTED TO MOVE INTO THE NW CWA BY SATURDAY EVENING AND REACH A PARIS TO DALLAS TO COMANCHE LINE BY SUNDAY MORNING. ANY LINGERING PRECIP WOULD FALL AS FREEZING RAIN. IT IS STILL TOO EARLY TO ANTICIPATE POSSIBLE ACCUMULATION OR IMPACTS...AND ANY SLIGHT DEVIATION IN THE FORECAST TEMPS WOULD GREATLY AFFECT THE ICE POTENTIAL. THE PRECIPITATION SHOULD FINALLY EXIT FROM WEST TO EAST DURING THE DAY SUNDAY WITH GENERALLY PARTLY CLOUDY AND DRY CONDITIONS EXPECTED INTO THE MIDDLE OF NEXT WEEK. IT WILL BE COLD...AND STAY RATHER CHILLY THROUGH WEDNESDAY. TEMPERATURES AROUND 20 FOR LOWS AND THE MIDDLE TO UPPER 30S FOR HIGHS APPEAR REASONABLE GIVEN THE SLOWLY MODIFYING LOW LEVEL THICKNESSES. WENT JUST A LITTLE COLDER THAN 12Z MEX MOS FOR LOWS...BUT 5-10 DEGREES COLDER FOR THE HIGHS. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 51 65 60 68 55 / 10 10 30 40 80 WACO, TX 53 66 61 70 62 / 10 10 30 40 40 PARIS, TX 45 59 58 66 57 / 10 10 30 40 80 DENTON, TX 50 64 58 67 48 / 10 10 30 40 80 MCKINNEY, TX 50 63 59 67 53 / 10 10 30 40 80 DALLAS, TX 52 65 61 69 58 / 10 10 30 40 80 TERRELL, TX 49 63 60 69 60 / 10 10 30 40 80 CORSICANA, TX 51 64 62 70 62 / 10 10 30 40 60 TEMPLE, TX 52 66 62 71 62 / 10 10 30 40 40 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/13/92 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 1225 AM PST WED JAN 10 2007 .SYNOPSIS...GUSTY WINDS WILL SLOWLY SUBSIDE OVERNIGHT AS A VIGOROUS COLD FRONT CONTINUES TO MOVE OUT OF THE REGION. AN UPPER LEVEL TROUGH WILL MOVE INTO THE REGION WEDNESDAY THIS WILL ALLOW A COLD ARCTIC AIRMASS TO MOVE INTO THE FORECAST AREA. THE COLD AIR WILL LIKELY PERSIST OVER THE INLAND NORTHWEST THROUGH THE END OF THE WEEK. && .DISCUSSION... REST OF TONIGHT....VIGOROUS COLD FRONT HAS NOW PASSED THROUGH MOST OF THE INLAND NW. AS OF 08Z...IT WAS LOCATED APPROXIMATELY SOUTHEAST OF A LINE FROM RITZVILLE TO COEUR D`ALENE TO SANDPOINT. WHILE AREAS NORTHEAST OF THIS LINE STAND LITTLE CHANCE OF MEASURABLE PRECIPITATION FOR THE REMAINDER OF THE NIGHT...THE SAME CANNOT BE SAID SOUTHEAST OF THE LINE. OVER THE PAST COUPLE HOURS...CLOUD TOPS HAVE COOLED SIGNIFICANTLY WHILE RADAR ECHOES HAVE BECOME WIDESPREAD. IT ALSO APPEARS THE FRONT HAS SLOWED ITS SE PROGRESSION AS IT BEGINS TO PARALLEL THE UPPER LEVEL FLOW. LOOKS LIKE THE RUC IS GRASPING AT THIS TREND...WHEREAS THE GFS AND NAM SEEM A LITTLE TOO FAST. IF THE RUC IS CORRECT THE FRONT WILL COMPLETELY EXIT THE CWA BY 15Z. BEFORE THAT TIME THOUGH WE EXPECT CATEGORICAL POPS TO CONTINUE TO ITS SE. THE OTHER CHANGE WAS TO LOWER SNOW LEVELS QUITE A BIT AS THE PRECIPITATION AT PULLMAN NEVER MATERIALIZED AS RAIN SUGGESTING A COOLER THAN EXPECTED WET- BULB PROFILE. LOOKS LIKE ALL AREAS WILL TURN TO SNOW BEFORE ALL IS SAID AND DONE...INCLUDING THE LEWISTON AREA. MOST ACCUMULATIONS OF SNOW SHOULD RANGE FROM 1-2 INCHES...HOWEVER WOULD NOT BE SURPRISED TO PICK UP SOME SPOTTY 3 INCH REPORTS OVER THE PALOUSE AND THE CENTRAL IDAHO PANHANDLE...BUT DO NOT EXPECT IT TO BE WIDESPREAD ENOUGH TO JUSTIFY A SNOW ADVISORY. OTHER UPDATE WAS TO RID THE WIND ADVISORY FOR THE NE MTNS AND EASTERN COLUMBIA BASIN AS WINDS HAVE ALREADY PEAKED THERE. OTHER ZONES TO FOLLOW AT 1 AM AS SYSTEM SEEMS TO BE PACKING GENERALLY WEAKER THAN ADVISORY WINDS AT THIS TIME. FX && .AVIATION...WINDS AND CHANCES OF PRECIPITATION WILL BE ON THE DECREASE FROM WEST TO EAST TONIGHT AS A COLD FRONT CONTINUES TO MOVE ACROSS THE AREA. WINDS CHANGING FROM SOUTHWEST TO MORE OF A WESTERLY COMPONENT. MVFR OR LOWER CONDITIONS ARE POSSIBLE ALONG THE CENTRAL PANHANDLE MOUNTAINS SOUTHWEST TO THE BLUES AS SNOW SHOWERS MAY REDUCE CEILINGS AND VISIBILITIES. OTHERWISE VFR CONDITIONS CAN BE EXPECTED THROUGH 21Z. AN UPPER TROUGH MOVING INTO THE AREA AFTER 21Z WED WILL RESULT IN LOWERING CEILINGS AND SCATTERED SNOW SHOWERS ACROSS THE EASTERN PORTION OF THE FORECAST AREA. ./TOBIN && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 25 27 10 15 1 13 / 10 30 30 0 0 0 COEUR D`ALENE 28 29 10 13 2 11 / 10 30 30 0 0 0 PULLMAN 30 31 11 17 3 13 / 90 20 30 20 0 0 LEWISTON 34 36 18 23 9 19 / 70 20 30 20 0 0 COLVILLE 24 27 5 13 -3 13 / 20 20 20 0 0 0 SANDPOINT 27 28 9 13 -4 11 / 20 30 20 0 0 0 KELLOGG 26 27 5 11 -1 11 / 90 50 30 10 0 0 MOSES LAKE 30 33 11 20 5 17 / 10 10 20 0 0 0 WENATCHEE 27 31 12 15 4 15 / 10 20 20 0 0 0 OMAK 24 27 2 8 -2 9 / 10 20 20 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...WIND ADVISORY UNTIL 1 AM PST EARLY THIS MORNING FOR COEUR D`ALENE AREA...IDAHO PALOUSE...LEWIS AND SOUTHERN NEZ PERCE COUNTIES...LEWISTON AREA. SNOW AND BLOWING SNOW ADVISORY UNTIL 10 AM PST THIS MORNING FOR LEWIS AND SOUTHERN NEZ PERCE COUNTIES. WA...WIND ADVISORY UNTIL 1 AM PST EARLY THIS MORNING FOR LOWER GARFIELD AND ASOTIN COUNTIES...SPOKANE AREA...WASHINGTON PALOUSE. SNOW AND BLOWING SNOW ADVISORY UNTIL 10 AM PST THIS MORNING FOR NORTHEAST BLUE MOUNTAINS. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 917 PM CST THU JAN 11 2007 .UPDATE...SOME LIGHT RAIN AND DRIZZLE HAS AFFECTED SOUTHWEST CORNER OF WI AND SMALL PART OF ADJACENT NORTHEAST IOWA ZONES THIS EVENING. THIS WAS ASSOCIATED WITH WAVE ADVANCING ALONG SURFACE FRONT...WHICH WAS STILL LITERALLY CRAWLING ACROSS SOUTHWEST CORNER OF WI. IN ADDITION...AREAS OF FOG DEVELOPED IN MOIST BOUNDARY LAYER WITH LIGHT WINDS IN THIS AREA. LATEST RUC INDICATED FORCING ASSOCIATED WITH ISENTROPIC LIFT ON THE 290K SURFACE...AS WELL AS Q-G CONVERGENCE...WAS ON THE WANE. THIS WAS CORROBORATED BY DECREASE IN PRECIPITATION OVER AFOREMENTIONED PART OF THE FORECAST AREA. DATA BASE HAS BEEN UPDATED TO INCORPORATE LATEST PRECIPITATION TRENDS...WHICH WILL HAVE DRIZZLE AND FOG ENDING BETWEEN 03Z-06Z THIS EVENING ACROSS SOUTHERN MOST SECTIONS OF THE FORECAST AREA. PLAN TO UPDATE ZONES BY 0330Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ THOMPSON wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1107 AM CST THU JAN 11 2007 .UPDATE... LATEST 16Z SURFACE ANALYSIS INDICATES SURFACE COLD FRONT EXTENDING FROM NORTHWEST WISCONSIN INTO NORTHEAST IOWA. TEMPERATURES OUT AHEAD OF FRONT WELL INTO THE UPPER 30S TO MIDDLE 40S. BEHIND THE FRONT TEMPERATURES IN THE MIDDLE TO UPPER 20S. LATEST 15Z RUC INDICATES SURFACE COLD FRONT TO CONTINUE TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON. 15Z RUC INDICATES SURFACE LOW OVER NORTHEAST KANSAS WILL MOVE NORTHEAST ALONG FRONT AND INTO SOUTHERN IOWA BY 00Z FRIDAY. BOTH THE 12Z NAM AND 15Z RUC CONTINUE TO INDICATE GOOD LOW LEVEL MOISTURE AND WEAK VERTICAL MOTION UP TO 750MB BY 21Z ACROSS SOUTHERN FORECAST AREA...AND WEAK ISENTROPIC LIFT AT 290K SURFACE. BOTH THE 12Z NAM AND 15Z RUC FORECAST SOUNDINGS INDICATE NO INTRODUCTION OF ICE INTO LOW LEVELS COMBINED WITH TEMPERATURES ABOVE FREEZING ALOFT AND AT SURFACE ACROSS SOUTHERN FORECAST AREA. PRECIPITATION WILL REMAIN ALL RAIN ACROSS SOUTHERN FORECAST AREA. WILL CONTINUE WITH PREVIOUS FORECAST THIS AFTERNOON AND UPDATE FOR MORNING WORDING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ DTJ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 320 PM CST WED JAN 10 2007 .DISCUSSION...FOCUS OF FORECAST ON MIXED PRECIPITATION EVENT THURSDAY NIGHT INTO FRIDAY...AND THREAT OF MORE SIGNIFICANT SCENARIO FOR LATE IN THE WEEKEND INTO MONDAY. SECOND PROBLEM WILL BE DEALT WITH IN EXTENDED DISCUSSION BELOW. STRONG WARM AIR ADVECTION HAS BEGUN WHICH WILL LAST INTO THURSDAY AHEAD OF APPROACHING SHORT WAVE TROUGH. CURRENT MID LEVEL CLOUDINESS ASSOCIATED WITH INITIAL SURGE THINNING AND PUSHING EASTWARD. CLOUD EDGE LINES UP WELL WITH LOWER CONDENSATION PRESSURE DEFICITS ON RUC 290 THETA SURFACE...WHICH CLEARS OUT TO THE EAST RAPIDLY THRU REMAINDER OF AFTERNOON. TEMPERATURES STRUGGLING TO GET INTO THE LOWER 30S IN THE WEST THIS AFTERNOON AND TO NEAR 30 IN THE EAST. EXPECT TEMPERATURES TO SLIP A FEW DEGREES THIS EVENING MOST AREAS...BUT THE STRONG WARM AIR ADVECTION AND SURFACE WINDS SHOULD KEEP TEMPERATURES IN CHECK MOST OF THE NIGHT. COLUMN MOISTURE INCREASES RAPIDLY ON THURSDAY AS PRECIPITABLE WATER INCREASES TO OVER ONE HALF INCH. BOTH GFS AND NAM DEPICT SHORT WAVE TROUGH OVER FAR SOUTHWEST EJECTING NORTHEAST INTO NORTHERN ILLINOIS LATER THURSDAY INTO FRIDAY. SYNOPTIC SCALE FORCING REMAINS QUITE WEAK AS DEPICTED BY LAYER Q-VECTOR CONVERGENCE FROM 850-700 THROUGH 500-300MB ON BOTH SHORT TERM MODELS...AS APPEARS SHORT WAVE BEGINS TO SHEAR OUT IT RACES NORTHEAST. 295 THETA SURFACE SHOWS CONDENSATION PRES DEFICITS LOWERING TO LESS THAN 10MB LATER THURSDAY AFTERNOON AND EVENING...HOWEVER ISENTROPIC OMEGA REMAINS WEAK. WAS TEETERING ON LOWERING POPS IN SOUTHEAST THURSDAY NIGHT WHERE CATEGORICAL NOW RUNNING BUT WL LEAVE ALONE FOR NOW AS FORCING NOT VERY IMPRESSIVE...AND LITTLE FORCING FROM FRONTEGENETICAL EFFECTS. HOWEVER LATEST SHORT TERM ENSEMBLE FORECAST CONTINUES TO SHOW HIGH PERCENTAGES FOR MEASURING THURSDAY NIGHT WITH RAPIDLY DIMINISHING TREND ON FRIDAY. BOTH GFS AND NAM NOW SHOWING MUCH WARMER LOW LEVEL THERMAL STRUCTURE LATER THURSDAY INTO FRIDAY...SO TRENDED MORE TOWARD RAIN FOR THURSDAY NIGHT WITH MIXTURE IN THE NORTHWEST WHERE LOW LEVEL THICKNESSES CRITICAL. NEEDED TO KEEP MIXTURE GOING INTO FRIDAY MOST AREAS AS SOUNDINGS SHOWING FEW IF ANY ICE CRYSTALS FALLING INTO CLOUD TOP. FORCING SLIDES OFF TO THE EAST ON FRIDAY AND FRIDAY NIGHT WITH LULL EXPECTED ON SATURDAY. HOWEVER FEW FLURRIES LINGERING IN EAST ON SATURDAY AS DELTA-T INCREASES TO 12 DEGREES WITH WEAK NORTH TO NORTHEAST LOW LEVEL FLOW SETTING UP. TWO DISTINCT CAMPS HAVE FORMED CONCERNING EJECTING SYSTEM FOR SUNDAY INTO MONDAY. GFS ENSEMBLE MEMBERS IN FAIR AGREEMENT ON AMPLIFYING LONG WAVE TROF DEVELOPING OVER WESTERN GREAT LAKES EARLY IN EXTENDED PERIOD. LAST SEVERAL RUNS OF GFS SHOWING GOOD CONSISTENCY ON PAIR OF UPSTREAM KICKERS RESULTING IN EJECTION OF UPPER LOW OVER SOUTHWESTERN CONUS ON SATURDAY INTO THE GREAT LAKES REGION BY MONDAY. MEDIUM RANGE ENSEMBLE SHOWING 60 PERCENT AND HIGHER LIKELIHOOD OF ACCUMULATING PRECIPITATION ACROSS SOUTHERN WISCONSIN SUNDAY NIGHT. WHILE GFS AND CANADIAN SHOW DEEPENING BUT PROGRESSIVE SYSTEM MOVING ACROSS VICINITY SUNDAY NIGHT...UKMT AND ECMWF KEY ON WEAKER SYSTEM MOVING ALONG BAROCLINIC ZONE DURING THIS SAME PERIOD. DESPITE DIFFERENCES IN STRENGTH OF SYSTEM...TIMING BETWEEN ALL EXTENDED GUIDANCE IN REASONABLE AGREEMENT. WITH BAROCLINIC ZONE SET UP ACROSS EASTERN IOWA INTO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS...AND DEEPER AVAILABLE MOISTURE...SEE NO PROBLEM IN BUMPING UP POPS TO LIKELY CATEGORY FOR AT LEAST ONE PERIOD...AND CARRY HIGH CHANCE POPS INTO MONDAY ACCOUNTING FOR POSSIBLE SLOWER EJECTION. ALSO... POTENTIAL PERIOD OF ISENTROPIC UPGLIDE DEVELOPING OVER SOUTHERN WISCONSIN SATURDAY NIGHT AND CONTINUING INTO SUNDAY COULD RESULT IN SEVERAL INCHES OF SNOW COVER AS SPECIFIC HUMIDITY BETWEEN 3 AND 4 GRAMS ON SUNDAY WITH SYNOPTIC SCALE FORCING AND STRONGER UPGLIDE POSSIBLE SUNDAY NIGHT INTO EARLY MORNING. HENCE POSSIBLE SNOWCOVER ACROSS MUCH OF REGION BY MONDAY NIGHT WILL GREATLY INFLUENCE TEMPERATURES FOR LATER PERIODS. MAY BE FLIRTING WITH ZERO BY TUESDAY NIGHT SOME AREAS. 5 DAY MEAN 500MB HEIGHT/ANOMOLY SHOWING TRANSITION PERIOD TO MORE SEASONAL WEATHER OVER NEXT SEVERAL DAYS. AMPLIFICATION OF LONG WAVE TROUGH OVER WESTERN CONUS NEXT SEVERAL DAYS WITH LARGE NEGATIVE HEIGHT ANOMOLY EXCEEDING 200 METERS...SPREADS EASTWARD INTO CENTRAL CONUS BY EARLY NEXT WEEK. NEGATIVE HEIGHTS EXCEEDING 100 METERS SPREADS INTO WISCONSIN...AND IS EXPECTED TO LINGER THROUGH MUCH OF NEXT WEEK. && .MKX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MBK wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 310 AM EST FRI JAN 12 2007 .SHORT TERM /TODAY THROUGH SUNDAY/...COASTAL TROF HANGING STRONG OFF THE CHS CWFA SHORE THIS MRNG AS EVIDENCED BY CONVERGING STREAMLINES ON MSAS ANALYSIS AND BUOYS WITH SE WINDS WHILE SHORELINE OBS ARE NE. TROF WILL HAVE A BIT OF A STRUGGLE LIFTING N AND AWAY FROM THE AREA THIS MRNG WITH STRONG HIGH PRES OFF THE MID ATLC COAST...AND THIS WILL HELP KEEP A FAIRLY DECENT MIDLVL CLOUD DECK IN PLACE THRU MOST OF THE DAY. ALTHOUGH IR SAT IMAGERY SHOWS MOCLR SKIES FOR INLAND SITES WHICH MATCH SFC OBS...CLOUD COVER OVER THE COASTAL WATERS WILL SLOWLY SPREAD INLAND AND COMBINE WITH LATE MRNG/EARLY AFTN CU DEVELOPMENT TO KEEP AT LEAST PTLY CLOUDY SKIES IN PLACE. THE ONLY SHOT AT PRECIP TDA WILL BE ALONG THE BEAUFORT-COLLETON-CHARLESTON COAST WHERE DEEPER MOISTURE AND MODEST LIFT WITHIN THE TROF ALONG WITH A SPOT VORTICITY MAXIMA WILL CONVERGE TDA. IF ANY PRECIP OCCURS IT WILL BE RATHER LIGHT...BUT JUST ENOUGH TO INCLUDE 20 POPS FOR ALONG THE COAST. DESPITE THE ANTICIPATED THICKER CLOUD COVER... SW TO W UPR FLOW TO THE W OF THE CWFA AND AN UPR LEVEL RIDGE AXIS OVER THE AREA WILL ALLOW THE WARMING TREND TO CONTINUE...FORCING MAX TEMPS TO ARND 70 DEGREES. SKIES WILL REMAIN GENERALLY PARTLY CLOUDY TNGT INTO SAT AS THE TROF APPEARS TO MORE DISSIPATE RATHER THAN LIFT NWD. LACK OF GOOD CONVERGENCE AND LESS MOISTURE IN THE 1000-500MB COLUMN SHOULD PREVENT SHOWER DEVELOPMENT OVERNIGHT AND TOMORROW SO WILL KEEP THE FCST DRY. TEMPS WILL REMAIN MILD TNGT AND TMRW WITH THE UPR LVL RIDGE AXIS SHIFTING EWD AND DEEPER SWLY FLOW TAKING HOLD. MIN TEMPS TNGT WILL DROP TO ARND 50 DEGREES WITH MAX TEMPS ON SAT RISING TO THE MID 70S. SIMILAR STORY SAT NIGHT INTO SUN WITH THE RIDGE AXIS MOVING FURTHER INTO THE ATLC WITH SFC HIGH PRES CENTERED WELL IN THE ATLC EXTENDING WWD OVER THE SE CONUS COAST. TEMPS WILL CONTINUE TO RISE SLIGHTLY... REACHING THE MID 50S FOR MIN TEMPS SAT NIGHT WITH MAX TEMPS ON SUN RISING INTO THE UPR 70S...MAKING 80 DEGREE READINGS NOT OUT OF THE QUESTION. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...MODELS STILL LOOK ON TRACK FOR A LOW PRES CENTER TO MOVE FROM THE SRN PLAINS INTO THE OH VLY SUN AND SUN NIGHT...WITH A TRAILING CDFNT TO MOVE ACRS TX AND INTO THE LWR MISS VLY. THIS FNT WILL DRAG ACRS THE GULF COAST STATES MON AND MON NIGHT...THEN SLOWLY MOVE ACRS THE SE STATES TUE AND TUE NIGHT. STILL SOME MINOR TIMING ISSUES ASSOCIATED WITH THIS SYSTEM... SO WILL LEAVE POPS CAPPED IN THE CHC CATEGORY. THE FNT THEN LOOKS TO STALL JUST S AND E OF THE AREA WED AND WED NIGHT WHICH MAY KEEP CLOUDS AND PRECIP IN THE AREA A BIT LONGER THAN ANTICIPATED. A SECONDARY CDFNT WILL THEN SWING THRU THE AREA THU WHICH WILL BRING A NOTICEABLY COOLER AIRMASS TO THE AREA FOR THE END OF THE WEEK. WITH TIMING ISSUES MAKING CONFIDENCE RATHER LOW...HAVE LEFT THE EXTENDED PORTION ALONE AND WILL LET A FULL MODEL AND HPC SLATE DURING DAY SHIFT DETERMINE THE OUTCOME OF THE EXTENDED. && .MARINE...A SHARP COASTAL TROF REMAINS PINNED ACROSS THE NEARSHORE WTRS THIS MRNG. THE 12/08Z OBSERVATIONS SUGGEST THE TROF AXIS EXTENDED FROM SAINT SIMMONS TO ABT 20 NM E OF THE CHARLESTON HARBOR ENTRANCE TO PSN OFF THE SE NC COAST. THE GFS/NAM BOTH INITIALIZED THE STRENGTH AND LOCATION OF THE COASTAL TROF POORLY AND ARE STILL WAY TOO QUICK IN MOVING IT INLAND TDA AS HIGH PRES SHIFTS FARTHER OFF THE MID-ATLC COAST. ONLY THE 12/03Z RUC SEEMS TO HAVE A GOOD HANDLE ON THE MESO-SCALE SITUATION AND WL BE CLOSELY FOLLOWED FOR THE NXT 6 HRS OR SO. PLAN TO KEEP SOLID NE WNDS GOING FOR MUCH OF THE MRNG ACROSS THE NEARSHORE WTRS THEN GRADUALLY VEER WNDS E/SE THROUGH THE AFTN. IT IS WORTH NOTING THAT THERE IS A REAL POSSIBILITY THAT WNDS MAY REMAIN NE WELL INTO THE AFTN ESP ACROSS THE SC WTRS UNTIL THE COASTAL TROF BECOMES OVERWHELMED BY THE INCRG SLY SYNOPTIC FLOW AND DISSIPATES. SE WNDS WL PREVAIL ACROSS THE GA OFFSHORE WTRS TDA WITH THE COASTAL TROF HOLDING JUST W OF AMZ374. THE PRES GRADIENT REMAINS PINCHED ALONG CHARLESTON COUNTY COAST THIS MRNG WHERE WNDS ARE SOLIDLY 15 KT WITH OCNL GUSTS TO 20 KT PER CARO-COOP AND C-MAN OBSERVATIONS. XPCT WNDS TO SLOWLY DIMINISH THROUGH THE MRNG BUT WL NEED TO BREAK OFF THE WTRS N OF EDISTO BEACH TO INITIALIZE SLGTLY HIGHER WNDS. SEAS WL GENERALLY REMAIN IN THE 3-4 FT RANGE ACROSS THE NEARSHORE WTRS TDA BUT WL HOLD IN THE 4-6 RANGE IN THE GA OFFSHORE WTRS WHERE A SMALL CRAFT ADVISORY WL BE MAINTAINED INTO THE AFTN. SLY WNDS WL PREVAIL FOR THE REMAINDER OF THE FCST PERIOD WITH THE MARINE AREA REMAINING ON THE WRN FRINGES OF ATLC HIGH PRES. A CDFNT IS FCST TO PUSH THROUGH THE WTRS ERLY NXT WEEK. && .AVIATION /06Z-06Z/...AN EXTENSIVE AMOUNT OF STRATOCU MOVING INLAND FROM THE ATLC WL IMPACT KCHS AND KSAV FOR MUCH OF THE MRNG. DESPITE THIS CIGS SHOULD REMAIN ABOVE MVFR THRESHOLDS...HOLDING AROUND 4000-5000 FT. MAY SEE SOME OF THE STRATOCU SCATTER OUT LTR THIS MRNG. WE MAY NEED TO REEVALUATE THIS WITH THE 12Z TAF CYCLE AS SOME OF THE SHORT TERM GUIDANCE SUGGESTS CIGS MAY HOLD WELL INTO THE AFTN ESP AT KCHS. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM FOR AMZ374. && $$ JPC/ST ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 330 AM CST FRI JAN 12 2007 .SYNOPSIS... ARCTIC BOUNDARY NOW THROUGH STATE AS OF 03Z WITH STRONG PUSH OF COLD AIR INTO THE NORTHERN PLAINS. MILD AIR IN THE 50S CONTINUES SOUTH OF THE FRONT WITH SUBZERO TEMPS GENERALLY ALONG AND NORTH OF I94 IN THE DAKOTAS. STRONG ARCTIC HIGH BUILDING INTO EASTERN MT ATTM WITH GREATEST PRESSURE RISES JUST BEHIND BOUNDARY IN EASTERN NEBRASKA AND KANSAS. IA REMAINS SHROUDED IN LOW STRATUS EXCEPT FOR THE FAR NW COUNTIES ATTM. A FEW FLURRIES REPORTED OVER SOUTHWEST SECTIONS TOO. UPPER AIR ANALYSIS SHOWS SECONDARY FRONTAL FEATURE OVER NORTHERN MN ALONG LEADING EDGE OF DEEPEST COLD AIR. ONLY SLIGHT REFLECTION CURRENTLY SEEN AT SFC. MAIN CHALLENGE TONIGHT WILL BE THE EXTENT OF SOUTHWARD MOVEMENT OF THE LOW STRATUS. CURRENT 11-3MU SHOWS SOME SOUTHWARD DRIFT BUT NOT MUCH. LARGER SCALE WATER VAPOR IMAGERY STILL SHOWS WESTERN TROUGH DIGGING SOUTH WITH MULTIPLE WAVES AT THE BASE OF THE TROUGH THOUGH SOME WEAKENING OF ENERGY ONGOING ATTM. .SHORT TERM (TODAY...SUN NIGHT)...MODELS IN SOME AGREEMENT TODAY TO BEGIN BREAKING UP CLOUDS AS WE HEAD INTO THE MORNING TO AFTERNOON HOURS. NAM12 AND RUC MODELS ARE MORE ADAMANT ABOUT HOLDING ONTO THE CLOUD COVER WHILE NAM/GFS PREFER TO BREAK THINGS UP A BIT. CLOUD TRENDS SUPPORT SOME PC SKIES LATER THIS MORNING THOUGH MOS GUIDANCE STILL HOLDS ONTO CLOUD COVER. INCREASING WINDS ALOFT WITH APPROACHING JET MAXES WILL LIKELY INCREASE HIGH LEVEL CLOUDS LATER IN THE AFTERNOON/EVENING EVEN IF BREAKS OCCUR THROUGH EARLY AFTERNOON. BEFORE THE MAIN UPPER TROUGH EJECTS NORTHEAST LATE SUNDAY INTO EARLY MONDAY THERE WILL LIKELY BE A FEW MINOR RIPPLES IN THE FLOW. MODELS ATTEMPTING TO RESOLVE THEM WITH SOME DIFFICULTY BUT THE GFS PICKS UP ON ONE OVERNIGHT TNT INTO EARLY SATURDAY MORNING. SOUNDINGS SHOW A BRIEF PERIOD OF LIFT WITH FLURRIES OR OR LIGHT FREEZING DRIZZLE POSSIBLE TNT WITH NAM SOUNDINGS DRYING OUT FASTER THAN THE GFS SOUNDINGS. WITH MAIN WAVE NOW COMING INTO PLAY LATER IN DAY ON SUNDAY...AM HOLDING OFF ON GREATER QPF AND SNOWFALL FOR THAT PERIOD AS QG FORCING ARRIVES TOWARD EVENING. AS UPPER LEVEL TROUGH LIFTS OVER THE STATE...DEFORMATION ZONE FORMS ON BACK SIDE OF SYSTEM WHICH SHOULD HELP PROLONG SNOWFALL INTO THE NIGHT AND EARLY MONDAY. BLOWING SNOW STILL APPEARS TO BE A PROBLEM WITH COLD TEMPS AND LIGHTER FLUFFY VARIETY EXPECTED. CURRENTLY EURO/GFS AND GEM SEEM TO HAVE THE BETTER HANDLE ON THE TIMING AND STRENGTH OF THE LOW. PROBLEM REMAINS THE AMT OF QPF WITH THE SYSTEM WHICH VARIES FROM ABOUT A HALF INCH WITH THE GFS TO NEARLY THREE QUARTERS WITH THE GEM. WITH TEMPS IN THE TEENS THROUGH THE BEST PERIOD OF SNOWFALL...HIGH SNOW TO WATER RATIOS EVEN .30 TO .40 WILL PROVIDE FOR AMTS OVER 6 INCHES. WITH UNCERTAINTY AS TO DETAILS OF PATH AND QPF...DONT FEEL CONFIDENT ISSUING A WATCH YET...BUT IF THE NEXT 2 RUNS CONFIRM THE PRESENT TRENDS...WATCH WILL PROBABLY BE NECESSARY LATER SUNDAY INTO THE NIGHT HOURS. SNOW CONTINUES INTO MONDAY MORNING WITH SOME BLOWING. .EXTENDED (MON...THUR)...COLD WEATHER TO FOLLOW WITH LITTLE IF ANY WARM UP UNTIL MID WEEK. MODELS HINT AT ANOTHER ARCTIC SHOT BY THE END OF THE OUTLOOK PERIOD. CERTAINLY THE COLDEST TEMPS IN QUITE SOME TIME WITH OVERNIGHT LOWS NEAR TO BELOW ZERO MON NIGHT/TUES NIGHT OVER SNOW COVERED AREAS ESPECIALLY. OF COURSE...ALL DEPENDS ON DEPTH OF SNOWPACK AND STORM THIS WEEKEND. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE && $$ REV ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 321 AM CST FRI JAN 12 2007 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE PRECIPITATION TYPE DURING THE NEXT 48 HOURS AND HOW MUCH ACCUMULATION WILL TAKE PLACE. TODAY: LATEST SURFACE ANALYSIS SHOWING THE COLD ARCTIC AIR CONTINUING TO PLUNGE ITS WAY THROUGH THE FORECAST AREA. TEMPERATURES HAVE NOW DROPPED WELL INTO THE TEENS ACROSS CENTRAL KANSAS WITH TEMPERATURES FLIRTING WITH THE FREEZING MARK IN SOUTHEAST KANSAS. THESE TEMPERATURES WILL CONTINUE TO TUMBLE AS THE MORNING WEARS ON. THE NEXT CONCERN IS SOME PRECIPITATION TRYING TO DEVELOP ACROSS SOUTHERN OKLAHOMA. THIS IS ASSOCIATED WITH A WEAK UPPER LEVEL WAVE MOVING THROUGH THAT REGION WHICH IS DISPLAYED ON THE 305K THETA SURFACE. THIS AREA OF LIFT WILL LIFT NORTHEAST INTO SOUTHEAST KANSAS BY MID MORNING WHICH COULD BRING SOME ICY CONDITIONS TO AREAS MAINLY EAST OF THE KANSAS TURNPIKE. QPF AMOUNTS ARE QUESTIONABLE AT THIS POINT...BUT I WOULD NOT SURPRISED IF SOME FOLKS SEE A TENTH TO TWO TENTHS OF AN INCH OF RAIN...BUT IT WILL TAKE A LITTLE FOR THE GROUND TEMPERATURES TO COOL OFF BEFORE ANY SIGNIFICANT ICING HAPPENS. THE NAM-WRF SOLUTION IS EVEN SHOWING SOME LIFT DEVELOP DURING THE AFTERNOON ACROSS EASTERN OKLAHOMA WHICH COULD BRING ANOTHER ROUND OF PRECIPITATION. RIGHT NOW...THIS LOOKS LIKE A FREEZING RAIN SITUATION DUE TO SUCH WARM AIR ALOFT. AT FIRST GLANCE...WE FELT CONFIDENT ENOUGH TO REMOVE THE WINTER WEATHER ADVISORY FOR PORTIONS OF SOUTH CENTRAL KANSAS. HOWEVER...BASED ON THE LATEST RUC/NAM-WRF SOLUTIONS THEY ARE ADVERTISING THE LOW LEVEL FLOW BACKING WHICH WILL INCREASE THE ISENTROPIC LIFT DURING THE AFTERNOON. WE WILL GO AHEAD AND MENTION A FREEZING RAIN ADVISORY FOR AREAS ALONG AND EAST OF THE TURNPIKE WHILE AREAS WEST OF THE TURNPIKE WE WILL KEEP THE WINTER WEATHER ADVISORY GOING THROUGH 00Z. TONIGHT: WE ARE PLANNING ON KEEPING THE WINTER STORM WATCH GOING FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE PERTURBATIONS IN SOUTHWEST FLOW ALOFT. THE NAM IS PICKING UP ON ANOTHER WAVE MOVING THROUGH THE FORECAST AREA TONIGHT WHILE THE GFS/UKMET ARE NOT SHOWING MUCH SUPPORT IN THIS. WE ARE GOING TO PLAY IT SAFE FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE UPPER LEVEL PATTERN. IF ANYTHING DOES DEVELOP THEN WE COULD SEE MORE MIXED PRECIPITATION DEVELOPING MAINLY IN CENTRAL KANSAS DUE TO COLDER AIR ALOFT WITH MORE FREEZING RAIN AND DRIZZLE DEVELOPING ELSEWHERE. SATURDAY-SUNDAY: LATEST WATER VAPOR LOOP IS SHOWING THE UPPER LEVEL TROF CONTINUING TO DIG. THE LATEST GFS AND UKMET ARE TENDING TO SLOW DOWN THE POSITION OF THIS TROF TOWARDS SUNDAY. THIS WILL TEND TO FAVOR MORE IN THE WAY OF FREEZING RAIN WITH PERIODS OF SLEET ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS THROUGH SUNDAY. CENTRAL KANSAS COULD STILL SEE SOME SNOW ON SUNDAY...BUT AMOUNTS ARE STILL TOO DIFFICULT TO TELL AT THIS JUNCTURE. MONDAY-TUESDAY: THIS UPPER LEVEL TROF IS EXPECTED TO SETTLE OVER OUR AREA DURING THESE TWO DAYS WHICH WILL KEEP THINGS UNSEASONABLY COLD BUT DRY. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 22 15 22 19 / 30 60 70 80 HUTCHINSON 19 14 20 16 / 30 60 70 80 NEWTON 21 14 21 19 / 30 60 70 80 ELDORADO 23 16 23 18 / 40 60 70 80 WINFIELD-KWLD 25 18 25 19 / 40 60 70 80 RUSSELL 15 10 14 10 / 20 60 70 80 GREAT BEND 15 11 16 13 / 20 60 70 80 SALINA 17 14 16 15 / 20 60 70 80 MCPHERSON 19 13 18 16 / 20 60 70 80 COFFEYVILLE 32 23 26 23 / 80 60 70 80 CHANUTE 29 21 25 21 / 70 60 70 80 IOLA 28 20 25 21 / 70 60 70 80 PARSONS-KPPF 30 22 26 22 / 80 60 70 80 && .ICT WATCHES/WARNINGS/ADVISORIES... FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ053- 069>072-093>096-098>100. WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY AFTERNOON FOR KSZ032-033-047>053-067>072-082-083-091>096-098>100. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ051- 052-067-068-082-083-091-092. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1005 AM EST FRI JAN 12 2007 .SHORT TERM /THIS AFTERNOON/...HIGH PRES CNTRD OVER THE WRN ATLC JUST E OF THE NC OUTER BANKS THIS MORNING WITH A COASTAL TROUGH HANGING TOUGH OVER THE SC/GA COASTAL WATERS. EARLY VIS SAT IMAGERY INDICATES SOME HIGH CLOUDS STREAMING E OVER THE AREA AND PLENTY OF STRATOCU OFF THE COAST TRYING TO WORK WWD. WITH A DECENT CU FIELD XPCTD THIS AFTN...THINK THERE WILL BE MORE CLOUDS THAN NOT THROUGH THE DAY...SO PARTLY SUNNY SKY COVER SHUD COVER IT. PLAN TO REMOVE THE SLGT CHC POPS FOR OUR NRN SC COUNTIES AS WE PREFER TO JUST MENTION ISO SHOWERS. HIGHS WILL TOP OUT AROUND 70 DEG AWAY FROM THE COAST...WITH TEMPS REMAINING IN THE MID TO UPPER 60S AT THE COAST DUE TO THE ONSHORE FLOW. ONLY MINOR TWEAKS TO THE GRIDS AND ZFP NEEDED. UPDATED ZFP OUT SHORTLY. && .MARINE...PREFER TO FOLLOW THE RUC DEPICTION OF THE COASTAL TROUGH AS THE GFS AND WRF CONTINUE TO INITIALIZE POORLY. THE LATEST OBS INDICATE WINDS AOB 15 KT WITH SEAS AOB 5 FT...HIGHEST OVER THE OUTER GA WATERS. TOUGH CALL ON THE SCA FOR AMZ374 AS SEAS HAVE BEEN FLIP-FLOPPING AROUND ADVISORY CRITERIA FOR A WHILE AND WILL LIKELY CONTINUE TO DO SO THROUGH THE AFTN WITH THE PESKY COASTAL TROUGH IN PLACE. WILL CONTINUE THE THINKING OF KEEPING SOLID NE WINDS GOING FOR THE MORNING ACROSS THE NEARSHORE WATERS...THEN GRADUALLY VEER WINDS E/SE THROUGH THE AFTN. E TO SE WINDS WILL PREVAIL ACROSS THE GA OFFSHORE WATERS TDA WITH THE COASTAL TROUGH HOLDING JUST W OF AMZ374. SEAS WILL GENERALLY REMAIN IN THE 3-4 FT RANGE ACROSS THE NEARSHORE WATERS TDA WITH 4-6 FT IN THE OUTER GA WATERS. OVERALL...NO MAJOR CHANGES NEEDED TO THE CWF WITH THE MID-MORNING UPDATE. && .AVIATION /12Z-12Z/...CONDITIONS XPCTD TO BE VFR THROUGH THE PERIOD ALTHO BKN CIGS ARE A GOOD BET ON/OFF THROUGH THE DAY...ESPCLY AT KCHS. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM FOR AMZ374. && $$ RJB ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1035 AM EST FRI JAN 12 2007 .UPDATE...RUC AND LAPS ANALYSIS SHOW THAT THE SFC TROUGH/COLD FRONT IS PRETTY MUCH THROUGH THE MOST OF N LOWER. THE NW FLOW IN E UPPER AND SFC TEMPERATURES FALLING INTO THE UPPER 20S ALONG LAKE SUPERIOR SHORELINE AT WHITEFISH POINT AND GRAND MARAIS SHOWING THAT THE COLD AIR IS BEGINNING TO OOZE INTO THE REGION. MID 30S IS THE RULE OVER MOST N LOWER WITH THE TEMPERATURES EXPECTED TO FALL DURING THE AFTERNOON. WINDS ARE BEGINNING TO SHIFT NORTH IN NW LOWER WITH RAWS SITE BEAR(SLEEPING BEAR DUNES NEAR EMPIRE) AND GRAND TRAVERSE LIGHT SHOWING NORTH WINDS AND MOST OF THE ASOS/AWOS SITES SHOWING NW WINDS. INTERIOR SITES AND NE LOWER SITES ARE EITHER CALM OR WINDS LIGHT SW. HIGHS HAVE BEEN REACHED OR WILL BE REACHED SOON, SO THE MAIN CONCERNS WILL BE THE HOURLY TEMPERATURES FALLING DURING THE DAY AND THE CHANCE FOR SNOW AS THE COLDER 850 AIR, AND SPECIFICALLY THE -10C LINE, ADVANCING INTO THE E UPPER AND N LOWER FOR THE AFTERNOON. AS OF 15Z RUC40 ANALYSIS/1HR FORECAST -10C WAS THROUGH MOST OF WHITEFISH BAY TO CURTIS LINE AND ADVANCING STEADILY. 12Z NAM IS MUCH SLOWER WITH THE -10C AIR AROUND MONTREAL RIVER, ONTARIO TO GRAND MARAIS, MI LINE. WITH KERY ALREADY SHOWING SNOW/FLURRIES WOULD THINK THAT THE 14Z RUC40 IS CLOSER TO REALITY. SO THINK THAT THE CURRENT FORECAST TRANSITIONS OF SNOW/DRIZZLE ARE CURRENTLY GOOD, BUT SFC TEMPERATURES NEED TO BE ADJUSTED SLIGHTLY. ZONES OUT SHORTLY. LUTZ && .PREV DISCUSSION...ISSUED 400 AM EST FRI JAN 12 2007 COLD FRONT EARLY THIS MORNING EXTENDED FROM NEAR THE SAULT...SW ACROSS LAKE MI AND SE WI...TO MISSOURI. RADAR AND SURFACE OBS SUPPORT DRIZZLE AND PATCHY LIGHT RAIN ACROSS FORECAST AREA. AS EXPECTED...FREEZING PRECIP HAS HELD OFF THUS FAR AS SURFACE TEMPS HAVE HELD ABOVE FREEZING IN ADVANCE OF FRONT. FRONT IS FORECAST TO DROP SE ACROSS THE REGION TODAY...REACHING SE LOWER MI BY LATE THIS AFTERNOON. AS COLDER AIR FILTERS SEWD BEHIND FRONT...FORECAST CONCERNS WILL INCLUDE PRECIP TYPE/COVERAGE THROUGH TONIGHT. TODAY AND TONIGHT...IR/WV LOOP SHOWS LITTLE IN THE WAY OF DEEP/LAYERED MOISTURE UPSTREAM...SUGGESTING THAT ANY PRECIP THAT FALLS TODAY WILL REMAIN ON THE LIGHT SIDE. THIS IS CONSISTENT WITH NAM/GFS MODEL SOUNDINGS...WITH SHALLOW MOISTURE GENERALLY CONFINED TO TEMPS OF -8C AND WARMER. CAA PATTERN WILL SUPPORT PROGRESSIVELY COOLER AIR FROM NW TO SE DURING THE DAY. AS A RESULT...EXPECT DRIZZLE OR PATCHY VERY LIGHT RAIN ACROSS NRN LOWER...WITH SOME PATCHY LIGHT MIXED PRECIP IN ERN UPPER EARLY. ANTICIPATE A GRADUAL TRANSITION TO SPOTTY LIGHT SNOW SHOWERS DURING THE AFTERNOON. HOWEVER...WILL RETAIN SOME PATCHY DRIZZLE THROUGH THE AFTERNOON IN SE AREAS...WHERE COOLER AIR ARRIVES LAST. COOLER AIR CONTINUES TO OVERSPREAD REGION TONIGHT...WITH 850 MB TEMPS FALLING TO AROUND -12C. N/NW WINDS WILL SUPPORT SOME LAKE EFFECT SNOW IN NW LOWER AND E UPPER THIS EVENING. HOWEVER...WITH SURFACE RIDGE DROPPING S THROUGH LAKE SUPERIOR...ANTI-CYCLONIC FLOW...INVERSION HEIGHTS NEAR 3 KFT...AND 850-700 MB RH HOVERING AROUND 60%...DON/T EXPECT MUCH ACCUMULATION. SATURDAY...COLD FRONT WILL DROP TO VICINITY OF OHIO RIVER AND STALL. LIGHT NORTHERLY FLOW ACROSS NRN MICHIGAN COUPLED WITH 850 MB TEMPS OF -12 TO -14C WILL SUPPORT MORNING FLURRIES EARLY NEAR LAKES MICHIGAN...HURON...AND SUPERIOR. HOWEVER...WITH SURFACE RIDGE DROPPING INTO NRN LOWER BY AFTERNOON...EXPECT FLURRIES TO END WITH PARTLY TO MOSTLY CLOUDY SKIES FOR THE AFTERNOON. SUNDAY...STALLED FRONT WILL REMAIN WELL S OF REGION...AS WAVES OF ENERGY PUSH ENEWD ALONG FRONT SPREADING SOME MOISTURE INTO CENTRAL AND SRN LOWER MI. MEANWHILE...A SURFACE TROUGH WILL DROP THROUGH THE NRN LAKES AND PROVIDE A REINFORCING SHOT OF COLDER AIR. UPSHOT... EXPECT MOSTLY CLOUDY SKIES WITH PATCHY LIGHT SNOW OR SNOW SHOWERS AND LITTLE IF ANY ACCUMULATION. SMITH SUNDAY NIGHT THROUGH TUESDAY...MOST POTENTIAL FOR SIGNIFICANT SNOWFALL OVER THE NEXT 7 DAYS FROM SUNDAY NIGHT THROUGH MONDAY. AT THIS TIME...NOT INCLINED TO MAKE ANY CHANGES TO THE ONGOING FORECAST. MODELS HAVE ACTUALLY BEEN DIVERGING THE PAST FEW RUNS...SO CANNOT PIN DOWN A MORE DEFINITIVE STORM TRACK AS OF THIS TIME. AS MENTIONED IN PREVIOUS DISCUSSIONS... THE TRACK OF A DEVELOPING STORM SYSTEM WILL PLAY A BIG ROLE AS TO HOW MUCH SNOW NORTHERN MICHIGAN SEES EARLY NEXT WEEK. THE 00Z GFS CONTINUES TO TREND FURTHER SOUTH WITH THE STORM TRACK...TAKING THE SYSTEM FROM CENTRAL KENTUCKY... THROUGH MARYLAND...THEN OFF INTO THE NORTHERN ATLANTIC. MEANWHILE...THE MORE CONSISTENT ECMWF KEEPS A NORTHERLY TRACK FROM SOUTHERN MISSOURI...THROUGH NORTHERN OHIO...AND INTO NORTHERN NEW ENGLAND. THE GFS SOLUTION WOULD YIELD LESS WIDESPREAD SNOWFALL... WITH MORE EMPHASIS ON LAKE EFFECT...WHILE THE ECMWF WOULD PROVIDE MORE OF A SUBSTANTIAL SNOWFALL TO THE AREA...ESPECIALLY NORTHEAST LOWER MICHIGAN...WHERE SNOWFALL WOULD BE ENHANCED WITH 850MB TEMPS STARTING OFF AROUND -8C...THEN FALLING RAPIDLY. MODELS SEEM TO AGREE ON KEEPING A LAKE INDUCED TROUGH OVER THE GREAT LAKES INTO TUESDAY. NORTH TO NORTHWEST FLOW WILL PROVIDE LAKE EFFECT SNOW SHOWERS TO LOCATIONS ALONG THE LAKE MICHIGAN AND LAKE HURON COASTLINES. OTHERWISE...THE TREND IN OVERALL SNOWFALL WILL BE ON THE DECLINE...ESPECIALLY ACROSS INTERIOR LOCATIONS OF NORTHERN MICHIGAN. KAS && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 557 AM CST FRI JAN 12 2007 .DISCUSSION... TOUGH FCST FOR FIRST MID SHIFT. ALL IN ALL THE PREVIOUS FCST WAS TRENDING IN THE RIGHT DIRECTION WITH SOME SIGNIFICANT ICING EXPECTED ACROSS PORTIONS OF THE AREA OVER THE NEXT FEW DAYS THEN SLEET AND SOME SNOW ON THE TAIL END. THE MODELS STILL APPEAR TO BE HAVING GREAT DIFFICULTY WITH TIMING AND STRENGTH OF THE COLD AIR ASSOCIATED WITH THE ARCTIC FRONT. THE FRONT HAS MOVED THRU KUIN AND KCOU IN THE LAST HOUR OR SO AND THE FREEZING LINE LAGS THE FRONT BY ONLY 75-80 NM. VERY MILD AIR AHEAD OF THE FRONT WILL BE DISPLACED THROUGHOUT THE DAY BY THE COLD ARCTIC AIR AS IT MOVES SEWD WITH FALLING TEMPERATURES IN THE WAKE OF THE FRONT. THE FRONT SHOULD MOVE THROUGH THE ST LOUIS AREA 15-17Z AND EXIT THE CWA NEAR 00Z. THE RUC ACTUALLY HAS THE BEST HANDLE WITH THE SURFACE TEMPERATURES AND THEY WERE LARGELY FOLLOWED THRU 18Z OR SO THEN SOME EXTRAPOLATION WAS USED THRU 00Z TNGT. THE FREEZING LINE SHOULD RESIDE 25 NM OR SO NW OF STL AT 00Z. FROM THAT POINT ON THE EXACT PUSH OF COLD AIR IS MORE QUESTIONABLE AS MUCH OF THE GUIDANCE HAS THE FREEZING LINE WAVERING ON A NE/SW AXIS BI-SECTING OR JUST SE OF KSTL THRU SUNDAY AFTERNOON...IMPACTED BY SURFACE WAVES TRAVELLING ALONG THE FRONT. PCPN LOOKS LIKE IT SHOULD COME IN 3 DISTINCT WAVES WITH THIS PROLONGED STORM SYSTEM. MUCH OF THE PCPN WITH THE FIRST 2 ROUNDS WITH BE VIA LIFT ASSOCD WITH WAA/ISENTROPIC UPGLIDE MODULATED BY WK MID LVL DISTURBANCES. THE LAST ROUND WILL BE ASSOCD WITH THE LIFTING MID-UPR SYSTEM. PCPN WITH THE FIRST ROUND IS IN THE DEVELOPMENT STAGE ATTM AND WE SHOULD CONT TO SEE RAIN DEVELOP THROUGH THE MORNING BECOMING FAIRLY WIDESPREAD ACROSS THE SRN 2/3RDS OF THE CWA BY AFTERNOON. RAIN THROUGH THE EVENING SHOULD BE FOCUSED ACROSS MUCH IN THE SAME AREA GRADUALLY SHUNTING SE OVERNIGHT. THE NEXT ROUND SHOULD THEN GET GOING SATURDAY AFTERNOON AND THE FINAL ROUND ON SUNDAY INTO SUNDAY EVENING. WITH THE FREEZING AIR POISED JUST NW OF STL BY 00Z TNGT I UPGRADED THE WATCH TO A WINTER STORM WARNING FOR KCOU AND KUIN AREAS BEGINNING LATER THIS MORNING WITH FREEZING RAIN EXPECTED. KEEP THE WATCH GOING FOR THE CORIDOOR THRU THE STL METRO AREA DUE TO THE UNCERTAINTY WITH THE WAVERING FREEZING LINE. FOR THE ENTIRE 3 DAY EVENT COULD SEE ICE ACCUMULATIONS OF ONE-HALF TO THREE- QUARTERS OF AN INCH JUST SOUTH OF AN AXIS FROM KCOU TO KIJX. TREES AND POWER LINES WILL BE MOST VULNERABLE. STILL ANTICIPATING SOME DECENT 2-3 INCHES RAINS ACROSS SE MO AND SRN IL WHICH MAY PROMPT SOME SMALL STREAM AND RIVER FLOODING...AS SUCH HAVE KEPT THE ESF GOING. GLASS && .AVIATION... FOR THE 12Z TAFS...ARCTIC COLD FRONT HAS JUST PASSED THROUGH UIN AND COU AND SHOULD CONT MOVG SEWD THRU STL AND SUS ARND 18Z WITH THE SFC WND VEERING ARND TO THE NW BHND THE CDFNT. STRATUS CLOUDS ALONG WITH FOG HAVE DVLPD IN UIN AND COU BHND THE CDFNT. THIS LOW LVL CLOUDINESS SHOULD ADVCT SEWD INTO THE STL METRO AREA LTR THIS MRNG INTO THE AFTN HRS AND WILL FCST FALLING CEILINGS FOR STL AND SUS...DROPPING TO ARND 1000 FT BY AFTN. A SFC WV WILL DVLP ALNG THE SEWD MOVG CDFNT BRINGING RAIN TO THE CWA THIS AFTN AND TGT. LOOKING AT THE MDL FCST SOUNDINGS THE TEMPERATURE SHOULD DROP TO 32 DEGREES F OR BLW IN UIN AND COU THIS AFTN CHANGING THE RAIN TO FREEZING RAIN. THERE IS MORE UNCERTAINTY WHEN THE RAIN WILL CHANGE OVER TO FREEZING RAIN IN THE STL METRO AREA AS MDLS HAVE THE SFC TEMPERATURE DROPPING CLOSE TO THE FREEZING MARK TGT. WILL MENTION A TEMPO GRP OF FREEZING RAIN IN STL AND SUS LT TGT AT THE END OF THE TAF FCST PERIOD. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY EVENING FOR CRAWFORD-FRANKLIN-JEFFERSON-ST. CHARLES-ST. LOUIS-ST. LOUIS CITY-WASHINGTON. WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST SUNDAY NIGHT FOR GASCONADE-LINCOLN-MONTGOMERY-OSAGE-WARREN. WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST SUNDAY NIGHT FOR AUDRAIN-BOONE-CALLAWAY-COLE-KNOX-LEWIS- MARION-MONITEAU-MONROE-PIKE-RALLS-SHELBY. IL...WINTER STORM WATCH FROM THIS EVENING THROUGH SUNDAY EVENING FOR CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL- MONROE IL-MONTGOMERY IL-ST. CLAIR IL. WINTER STORM WARNING FROM 9 AM THIS MORNING TO MIDNIGHT CST SUNDAY NIGHT FOR ADAMS IL-BROWN IL-PIKE IL. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 305 AM PST FRI JAN 12 2007 .SYNOPSIS...A COLD UPPER LOW WILL SLOWLY MIGRATE ACROSS THE SOUTHERN GREAT BASIN AND MOJAVE DESERT TODAY AND SATURDAY. SNOW SHOWERS WILL OCCUR OVER MUCH OF THE REGION WITH HEAVIER SNOW BANDS OCCURRING OVER LINCOLN AND MOHAVE COUNTIES. TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE WEEKEND AND INTO NEXT WEEK. && .SHORT TERM...SO MUCH TO TALK ABOUT THIS MORNING. WILL HIT THE HIGH POINTS HERE...THE INTERESTED READER MAY WANT TO REFER TO THE RNOWSWVEF...RNOSPSVEF...AND RNOHWOVEF PRODUCTS FOR MORE DETAILS. IN LINCOLN COUNTY...SIGNIFICANT SNOW BEGAN A FEW HOURS EARLIER THAN EXPECTED. THE SHERIFFS OFFICE IN PIOCHE REPORTED SIX INCHES ON THE GROUND AT 1 AM...SO UPGRADED THE SNOW ADVISORY TO A HEAVY SNOW WARNING. ALSO MOVED THE EXPIRATION TIME BACK FROM 4 AM SATURDAY TO 10 PM THIS EVENING AS IT APPEARS THE SIGNIFICANT SNOW WILL BE OVER BY THEN. IN CLARK COUNTY...THE COLD FRONT ROLLED THROUGH LAS VEGAS BETWEEN 2 AND 3 AM THIS MORNING. POST FRONTAL SNOW SHOWERS WERE FALLING AS FAR SOUTH AS INDIAN SPRINGS...BUT WERE NOT MAKING IT ACROSS THE MOUNTAINS INTO THE LAS VEGAS VALLEY. THE WINTER STORM WATCH IS A REAL CONUNDRUM. NAM...GFS...AND RUC MODELS ARE HINTING MORE STRONGLY AT A DRY SLOT AFFECTING THE INTERSTATE 15 CORRIDOR THIS AFTERNOON. HOWEVER...THEY ALSO STILL SHOW SOME UPWARD MOTION THROUGH A SATURATED LAYER IN OR NEAR THE -12C TO -18C "SWEET SPOT" FOR DENDRITIC SNOW CRYSTAL GROWTH. THERE IS MORE UNCERTAINTY THAN NORMAL WITH THIS FORECAST...BUT THE MIDPOINT OF THE POSSIBLE RANGE OF OUTCOMES FALLS INTO THE SNOW ADVISORY CATEGORY...SO UPGRADED THE WATCH TO AN ADVISORY. THE SNOW MAY BE MORE SHOWERY IN NATURE AS THE COLD UPPER LOW MOVES OVERHEAD. IN MOHAVE COUNTY...THE MODELS ALL SUGGEST BETTER MOISTURE AVAILABILITY SOUTHEAST OF THE POSSIBLE DRY SLOT. PREVIOUS SHIFT HAD ALREADY ISSUED A SNOW ADVISORY THERE...AND THIS STILL LOOKS GOOD. RESIDUAL MOISTURE WILL LINGER THROUGH MUCH OF SATURDAY...THEN THE BEST WINDOW OF OPPORTUNITY FOR CLEAR SKIES COMES ON SUNDAY MORNING. BIG QUESTION AFFECTING HOW COLD IT WILL GET IS WHETHER OR NOT THE NORTH WINDS WILL RELAX BY THEN. IF THE WINDS RELAX...TEMPERATURES WILL REALLY BOTTOM OUT...BUT IF THE WINDS ARE STILL BLOWING THE WIND CHILLS WILL BE WORSE...SO EITHER WAY IT WILL BE DANGEROUS TO UNSHELTERED FOLKS. SPS AND HWO HAVE BEEN/WILL BE ISSUED FOR THIS. THE MOST RECENT EVENTS SIMILAR TO THIS ONE AT MCCARRAN AIRPORT WERE A LOW OF 23F ON JANUARY 31 2002...AND A LOW OF 20F ON DECEMBER 22 1998. IF MCCARRAN REACHES 23F AS FORECAST ON SUNDAY MORNING...MANY PARTS OF THE VALLEY WILL BE IN THE TEENS. WRAP THOSE PIPES...DRIP THOSE FAUCETS...BRING THOSE PLANTS AND PETS INSIDE...ET CETERA. .LONG TERM...SHORTWAVE MOVING THROUGH THE CWA MONDAY WILL BRING A REINFORCING SHOT OF COOLER AIR...GUSTY WINDS DOWN THE COLORADO RIVER AND A FEW CLOUDS. EXPECT ANY PRECIPITATION TO REMAIN WELL EAST OF THE AREA AND WILL KEEP THE CURRENT ZERO POPS IN THE FORECAST. RIDGING WILL DEVELOP OVER THE AREA WEDNESDAY BUT EXPECT TEMPERATURES TO REMAIN BELOW NORMAL DUE TO LIGHT WINDS AND DAILY MORNING INVERSIONS. GFS IS SHOWING A LOW TO MOVE DOWN THE CA COAST AND EVENTUALLY PINCH OFF THE RIDGE AND FORM A REX BLOCK OVER THE WESTERN STATES. THE GFS/DGEX/ECMWF ARE HINTING AT THE LOW EVENTUALLY TURNING EAST AND PUSHING INTO THE CWA. RIGHT NOW THE MODELS ARE SHOWING LITTLE MOISTURE ASSOCIATED WITH THIS SYSTEM AND MAINLY JUST AN INCREASE IN CLOUDS. HAVE NOT INTRODUCED ANY POPS INTO THE FORECAST AND WILL WAIT FOR FUTURE MODEL RUNS. && .AVIATION...COLD FRONT CURRENTLY MOVING THROUGH SOUTHERN NEVADA WITH LIGHT SNOW REPORTED AT DRA. PRECIPITATION WILL SLOWLY WORK SOUTH TODAY WITH RAIN AND SNOW SHOWERS EXPECTED IN THE LAS VEGAS VALLEY. CIGS MAY BRIEFLY DROP TO BELOW 5000 FEET WITH VSBYS BELOW 5SM...BUT DO NOT EXPECT IT TO BE A WIDESPREAD AND PROLONGED EVENT. HEAVIER SNOWS WILL LIKELY AFFECT THE MORMON MESA AND PEACH SPRINGS CORRIDORS WHERE A COUPLE OF INCHES OF SNOW MAY FALL. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .VEF WATCHES/WARNINGS/ADVISORIES... .NV...HEAVY SNOW WARNING ZONE 15 THROUGH 10 PM. SNOW ADVISORY ZONES 16 20 AND 22 2 PM THROUGH 10 PM. .AZ...SNOW ADVISORY ZONES 1 AND 3 11 AM THROUGH 11 PM. .CA...NONE. $$ MORGAN/GORELOW HTTP://WEATHER.GOV/LASVEGAS nv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 935 AM CST FRI JAN 12 2007 .UPDATE... WITH THE PROXIMITY OF THE COLD FRONT AND THE ONGOING PRECIPITATION HAVE ISSUED AN ICE STORM WARNING FOR HASKELL AND THROCKMORTON COUNTIES FROM 18Z TODAY THROUGH MONDAY. && .PREV DISCUSSION... /ISSUED 904 AM CST FRI JAN 12 2007/ UPDATE... DESPITE A LOT OF UNCERTAINTY HAVE EXTENDED WINTER STORM WATCH TO THE SOUTH TO INCLUDE STERLING...COKE...RUNNELS ...COLEMAN AND BROWN COUNTIES. THESE COUNTIES ARE ON THE BORDER OF WHERE THE FREEZING DRIZZLE AND FREEZING RAIN IS EXPECTED TO OCCUR. PREV DISCUSSION... /ISSUED 649 AM CST FRI JAN 12 2007/ AVIATION... A LOW-LEVEL JET WILL CONTINUE TO PRODUCE LOW-LEVEL WIND SHEAR ACROSS WEST CENTRAL TEXAS THIS MORNING. LOW CLOUDS WILL CONTINUE TO REDEVELOP AND MOVE INTO THE AREA THIS MORNING. CEILINGS WILL CONTINUE TO DROP INTO THE MVFR CATEGORY TODAY. A STRONG COLD FRONTAL BOUNDARY IS EXPECTED TO REACH THE ABILENE TERMINAL SHORTLY AFTER 00Z. IN ADDITION...EXPECT LIGHT RAIN TODAY. EXPECT FREEZING RAIN OR FREEZING DRIZZLE ACROSS THE BIG COUNTRY AFTER MIDNIGHT TONIGHT AS COLD ARCTIC AIR PUSHES SURFACE TEMPERATURES TO OR BELOW THE FREEZING MARK. FREEZING RAIN OR FREEZING DRIZZLE WILL THEN CONTINUE ACROSS THE BIG COUNTRY THROUGH 12Z TOMORROW MORNING. 23/HUBER PREV DISCUSSION... /ISSUED 435 AM CST FRI JAN 12 2007/ DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-CALLAHAN-COKE-COLEMAN-FISHER-JONES-NOLAN-RUNNELS- SHACKELFORD-STERLING-TAYLOR. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR HASKELL-THROCKMORTON. && $$ 28/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 904 AM CST FRI JAN 12 2007 .UPDATE... DESPITE A LOT OF UNCERTAINITY HAVE EXTENDED WINTER STORM WATCH TO THE SOUTH TO INCLUDE STERLING...COKE...RUNNELS ...COLEMAN AND BROWN COUNTIES. THESE COUNTIES ARE ON THE BORDER OF WHERE THE FREESING DRIZZLE AND FREEZING RAIN IS EXPECTED TO OCCUR. && .PREV DISCUSSION... /ISSUED 649 AM CST FRI JAN 12 2007/ AVIATION... A LOW-LEVEL JET WILL CONTINUE TO PRODUCE LOW-LEVEL WIND SHEAR ACROSS WEST CENTRAL TEXAS THIS MORNING. LOW CLOUDS WILL CONTINUE TO REDEVELOP AND MOVE INTO THE AREA THIS MORNING. CEILINGS WILL CONTINUE TO DROP INTO THE MVFR CATEGORY TODAY. A STRONG COLD FRONTAL BOUNDARY IS EXPECTED TO REACH THE ABILENE TERMINAL SHORTLY AFTER 00Z. IN ADDITION...EXPECT LIGHT RAIN TODAY. EXPECT FREEZING RAIN OR FREEZING DRIZZLE ACROSS THE BIG COUNTRY AFTER MIDNIGHT TONIGHT AS COLD ARCTIC AIR PUSHES SURFACE TEMPERATURES TO OR BELOW THE FREEZING MARK. FREEZING RAIN OR FREEZING DRIZZLE WILL THEN CONTINUE ACROSS THE BIG COUNTRY THROUGH 12Z TOMORROW MORNING. 23/HUBER PREV DISCUSSION... /ISSUED 435 AM CST FRI JAN 12 2007/ DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-CALLAHAN-COKE-COLEMAN-FISHER-HASKELL-JONES-NOLAN- RUNNELS-SHACKELFORD-STERLING-TAYLOR-THROCKMORTON. && $$ 28/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 649 AM CST FRI JAN 12 2007 .AVIATION... A LOW-LEVEL JET WILL CONTINUE TO PRODUCE LOW-LEVEL WIND SHEAR ACROSS WEST CENTRAL TEXAS THIS MORNING. LOW CLOUDS WILL CONTINUE TO REDEVELOP AND MOVE INTO THE AREA THIS MORNING. CEILINGS WILL CONTINUE TO DROP INTO THE MVFR CATEGORY TODAY. A STRONG COLD FRONTAL BOUNDARY IS EXPECTED TO REACH THE ABILENE TERMINAL SHORTLY AFTER 00Z. IN ADDITION...EXPECT LIGHT RAIN TODAY. EXPECT FREEZING RAIN OR FREEZING DRIZZLE ACROSS THE BIG COUNTRY AFTER MIDNIGHT TONIGHT AS COLD ARCTIC AIR PUSHES SURFACE TEMPERATURES TO OR BELOW THE FREEZING MARK. FREEZING RAIN OR FREEZING DRIZZLE WILL THEN CONTINUE ACROSS THE BIG COUNTRY THROUGH 12Z TOMORROW MORNING. 23/HUBER && .PREV DISCUSSION... /ISSUED 435 AM CST FRI JAN 12 2007/ DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR CALLAHAN-FISHER-HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR- THROCKMORTON. && $$ 23/HUBER tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 435 AM CST FRI JAN 12 2007 .DISCUSSION... A COMPLICATED FORECAST WILL CONTINUE THROUGH THE WEEKEND AS THE ARCTIC FRONT CONTINUES TO CRASH THROUGH THE SOUTHERN PLAINS. LATEST SFC ANALYSIS SHOWS ARCTIC FRONT LOCATED FROM KTUL TO KOKC TO KCDS. EXPECT THE FRONT TO PUSH INTO THE BIG COUNTRY REACHING AN I-20 LINE BETWEEN 21Z AND 00Z. RUC/NAM SOLUTIONS SEEM TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT WITH THE GFS INITIALIZING SLIGHTLY WARMER WITH THE COLD AIR. GFS CONTINUES TO BE SLOWER WITH THE FRONTAL PUSH AS WELL. THE MAIN CHALLENGE CONTINUES TO BE HOW MUCH PROGRESS THE FRONT MAKES BEFORE STALLING AHEAD OF THE UPPER LEVEL TROUGH THAT IS EXPECTED TO PULL OUT OF THE SOUTHERN ROCKIES. BOTH 00Z AND 06Z NAM/GFS RUNS BRING THE FRONT INTO THE CONCHO VALLEY/HEARTLAND FRI NIGHT. THINK THE FRONT MAY STALL SOUTH OF A KSJT TO KBBD LINE BY SAT MORNING. FRONT WILL BE MAIN FORCING FOR PRECIPITATION DURING THE WEEKEND WITH STRONG ISENTROPIC LIFT OVER THE FRONTAL SURFACE THROUGH MUCH OF THE WEEKEND. SHOULD SEE CONTINUAL FREEZING DRIZZLE WHERE TEMPS NEAR THE SFC ARE COLD ENOUGH. OTHERWISE...FRONT SHOULD BE ON THE MOVE MORE ON SUNDAY AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE PLAINS. STRONG FRONTOGENETIC LIFT WILL BE POSSIBLE SUN NIGHT AS 850MB FRONT FINALLY PUSHES THROUGH THE REGION. WILL CARRY POPS THROUGH THIS TIME PERIOD. HIGH PRESSURE SHOULD CONTINUE TO BUILD INTO THE REGION MON AND TUE. WHILE PRECIP CHANCES LOOK GOOD THROUGH THE WEEKEND...OTHER FORECAST CHALLENGE WILL BE PRECIP TYPE. EXPECT ISOLATED THUNDERSTORMS AND SHOWERS AHEAD OF THE FRONT AND POSSIBLY LAST INTO THIS EVENING FOR THE BIG COUNTRY AS THERE MAY BE SOME ELEVATED INSTABILITY FOR CONVECTION. OTHERWISE THUNDERSTORM ACTIVITY WILL BE CONFINED TO WARM SECTOR SOUTH OF THE FRONT THROUGH THE WEEKEND. WILL LIKELY SEE FREEZING TEMPS WORK THEIR WAY INTO THE BIG COUNTRY MAINLY ALONG I-20 NORTHWARD TONIGHT INTO SAT MORNING. TEMPS MAY WARM A LITTLE TO ABOVE FREEZING ON SAT SO MAY SEE A MIX OF FREEZING RAIN AND RAIN DURING THE DAY. THREAT OF FREEZING RAIN WILL CONTINUE SAT NIGHT AS UPPER LEVEL TROUGH PULLS INTO THE PLAINS WITH SEVERAL DISTURBANCES IN THE JET. MAIN QUESTION WILL BE HOW FAR SOUTH FREEZING TEMPS WILL EXTEND. FOR NOW WILL KEEP FREEZING TEMPS CONFINED TO THE BIG COUNTRY AND KEEP MOST OF THE CONCHO VALLEY AND HEARTLAND NEAR OR ABOVE FREEZING WITH PRECIP TYPE BEING RAIN. TEMPS ON SUNDAY SHOULD DROP DURING THE DAY WITH PRECIP CHANCES DROPPING OFF INTO MONDAY. A WINTER STORM WATCH WILL CONTINUE FOR THE BIG COUNTRY BUT COULD BE UPGRADED. RIGHT NOW IT LOOKS LIKE ICE ACCUMULATIONS WILL REMAIN BELOW CRITERIA BUT THIS COULD CHANGE IF FREEZING TEMPS MOVE INTO THE AREA FASTER THAN EXPECTED. THIS MAY BE POSSIBLE CONSIDERING THE FRONTAL MOVEMENT BEING FASTER THAN WHAT THE MODELS HAVE BEEN SHOWING. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 62 29 36 28 / 50 60 60 70 SAN ANGELO 67 50 51 38 / 50 50 60 70 JUNCTION 67 59 62 56 / 60 60 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY AFTERNOON FOR CALLAHAN-FISHER-HASKELL-JONES-NOLAN-SHACKELFORD-TAYLOR- THROCKMORTON. && $$ 10 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 422 PM EST FRI JAN 12 2007 .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...PRETTY MUCH STATUS QUO AS THE SFC MAP IS CONCERNED WITH HIGH PRES CNTRD TO OUR NE OVER THE WRN ATLC WITH RIDGING EXTENDING ACROSS MUCH OF THE SERN CONUS. MEANWHILE...A COASTAL TROUGH REMAINS IN PLACE OFF THE SC/GA COASTS. STRATOCU ASSCD WITH THE TROUGH HAS HAD A HARD TIME MAKING IT ONSHORE AND TEMPS THIS AFTN HAVE SOARED INTO THE MID 70S ACROSS MUCH OF THE AREA. SHUD SEE THE TROUGH DISSIPATE TONIGHT AS THE SFC HIGH MOVES FARTHER E. SKIES WILL END UP BEING PCLDY AND WITH LGT WINDS...CUD SEE SOME PATCHY FOG BUT NOT ENOUGH TO INCLUDE IN THE FCST ATTM. LOWS WILL RANGE FROM THE UPPER 40S INLAND TO MID 50S ALONG THE COAST. OUTSIDE OF A DECENT CU FIELD AND SOME HIGH CLOUDS...XPCT ENOUGH SUN TOMORROW TO ALLOW TEMPS TO CLIMB INTO THE MID 70S...A GOOD 15 DEG ABOVE NORMAL. A MILD S TO SW FLOW TOMORROW NIGHT WILL KEEP TEMPS A DEG OR TWO WARMER THAN TONIGHT...RANGING FROM AROUND 50 DEG INLAND TO THE UPPER 50S ALONG THE COAST...STILL ABOUT 15 DEG ABOVE NORMAL. && .LONG TERM /SUNDAY THROUGH FRIDAY/...STRONG RIDGING BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE AREA SUN INTO MON...THEN WILL GIVE WAY TO NEXT UPSTREAM COLD FRONT TUE. UNSEASONABLY WARM CONDITIONS TO PREVAIL ACROSS THE CWFA AHEAD OF THE FRONT EARLY IN THE WEEK...WITH POSSIBLE 80 DEGREE TEMPS NOT OUT OF THE QUESTION ACROSS A FEW SECTIONS OF THE SRN CWFA. A LARGE TEMP GRADIENT TO PREVAIL BOTH AFTNS...WITH COOLING SEA BREEZE INFLUENCES. WILL KEEP WATCH ON POSSIBLE COASTAL SHRA WITH STRENGTHENING AND DEEPENING S-SW FLOW SUN NIGHT/MON...BUT FOR NOW FEEL THAT STEERING FLOW WILL KEEP ANY SHRA OVER THE ATLC. POPS WILL THEN INCREASE INTO THE CHANCE RANGE ON TUE WITH THE FRONTAL PASSAGE. FRONT WILL SLOWLY MOVE SE OF THE AREA TUE NIGHT/WED...AND WILL LIKELY STALL ACROSS THE SW ATLC AND FL...AS HIGH PRES SLOWLY BUILDS FROM THE N AND W. HOWEVER...OVERRUNNING OF MOISTURE BEHIND THE FRONT AND ISENTROPIC LIFTING WILL RESULT IN PLENTY OF CLOUDS AND LINGERING RAINS DURING THE MIDDLE OF THE WEEK. AT THIS POINT THERE IS AT LEAST A SMALL CHANCE THAT THE COLDER AIR MAY RESULT IN SOMETHING OTHER THAN RAIN ACROSS SOME OF THE NRN MOST AREAS...BUT THERE IS WAY TOO MUCH UNCERTAINTY AT THIS TIME TO GO WITH ANYTHING OTHER THAN RAIN IN THE FCST. EVEN SO...COMBINATION OF CLOUD COVER AND CAA WILL HOLD TEMPS ON WED DOWN IN THE 40S OR LOWER 50S MOST AREAS. DRIER AND EVEN COLDER WX TO MOVE IN LATE IN THE WEEK...WITH POSSIBLE FREEZING TEMPS THU AND FRI MORNING ACROSS INLAND AREAS. && .MARINE...A COASTAL TROUGH LINGERS OFF THE SC/GA COASTS THIS AFTN BUT SHUD FINALLY BEGIN TO BREAK DOWN TONIGHT AS THE SFC HIGH TO THE N AND E SHIFTS FARTHER E. WILL HAVE E TO NE WINDS THE FIRST HALF OF THE NIGHT OVER THE NEARSHORE WATERS...VEERING TO E/SE LATE...MORE IN LINE WITH THE RUC WHICH HAS HAD THE BEST HANDLE ON THIS FEATURE. THE SCA FOR THE OUTER GA WATERS IS STILL AN ISSUE AS SEAS HAVE BEEN 4-5 FT AT THE R2 TOWER TDA. THE WNA GUIDANCE SHOWS SEAS BUILDING TO 5 FT AT 41008 TONIGHT BUT CANNOT BUY INTO THIS SINCE IT IS BASED ON THE SLIGHTLY STRONGER WINDS OF THE GFS. PREFER TO CANCEL THE SCA WITH THE AFTN PACKAGE AND REPLACE IT WITH A SCSEC HEADLINE INSTEAD. MAY SEE SOME 6 FT SEAS COME BACK INTO THE PICTURE TOMORROW NIGHT AS A MORE SOLID SLY FLOW BECOMES ESTABLISHED BUT WILL NOT BE RAISING THAT HEADLINE ATTM. OTHERWISE...WINDS XPCTD TO REMAIN AOB HEADLINE CRITERIA THROUGH SAT NIGHT. ATLC RIDGING ACROSS THE AREA SUN AND EARLY MON WILL SHIFT SE AND GIVE WAY TO AN APPROACHING COLD FRONT MON NIGHT/EARLY TUE. THE FRONT WILL SLOWLY MOVE THRU THE AREA DURING TUE AS STRONG HIGH PRES BUILDS FROM THE NW AND N. THE COMBINATION OF CAA AND PINCHED GRADIENT WILL LIKELY RESULT IN AT LEAST SCA HEADLINES IN WAKE OF THE FRONT TUE NIGHT/WED. DEPENDING UPON IF WINDS ARE MORE N OR NE DURING THIS TIME WILL HELP DETERMINE HOW HIGH SEAS WILL REACH...AND I MAY HAVE GONE A LITTLE CONSERVATIVE GIVEN SOME UNCERTAINTY IN THE EXACT FETCH. EVEN SO...SEAS WILL BUILD TO AT LEAST 5 OR 6 FT WITHIN 20 NM OF THE COAST...AND UP TO 8 OR 9 FT FURTHER OFFSHORE. LOCAL SEA BREEZE INFLUENCES WILL BACK WINDS TO SE OR S NEAR THE COAST SUN AND MON AFTN. && .AVIATION /18Z-18Z/...CONDITIONS XPCTD TO BE VFR THROUGH THE PERIOD. MAY SEE SOME PATCHY FOG TONIGHT BUT AT THIS POINT FELT CHANCES WERE TOO LOW TO MENTION. && .CHS WATCHES/WARNING ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ RJB/33 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1133 AM CST FRI JAN 12 2007 .UPDATE... COLD AIR HAS REALLY SURGED INTO KANSAS OVERNIGHT...AND CONTINUES ITS SOUTHEASTWARD PROGRESS DURING THE DAY TODAY. LOWEST 3000FT OR SO OF THE SOUNDINGS IN SOUTH CENTRAL KANSAS ARE BELOW -6.6C...THE CRITICAL TEMPERATURE AND DEPTH TO BE ABLE TO GET SNOW CRYSTALS DESPITE THE WARM AIR ALOFT. THEREFORE...WITH THE TEMPERATURES EXPECTED TO REMAIN NEARLY STEADY OR FALL A FEW MORE DEGREES...EXPECT THE PRECIPITATION TYPE IN THIS REGION TO REMAIN SNOW. FURTHER SOUTHEAST...WITH SLIGHTLY WARMER TEMPERATURES EXPECT MORE OF A MIXTURE OF FREEZING RAIN AND SLEET...AND MAYBE SOME SNOW MIXED IN AT TIMES. MADE THESE CHANGES IN THE FORECAST AND LOWERED TEMPERATURES TO COME MORE IN LINE WITH THE QUICKER ARCTIC AIR INTRUSION. SCHRECK && .PREV DISCUSSION... /ISSUED 321 AM CST FRI JAN 12 2007/ DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE PRECIPITATION TYPE DURING THE NEXT 48 HOURS AND HOW MUCH ACCUMULATION WILL TAKE PLACE. TODAY: LATEST SURFACE ANALYSIS SHOWING THE COLD ARCTIC AIR CONTINUING TO PLUNGE ITS WAY THROUGH THE FORECAST AREA. TEMPERATURES HAVE NOW DROPPED WELL INTO THE TEENS ACROSS CENTRAL KANSAS WITH TEMPERATURES FLIRTING WITH THE FREEZING MARK IN SOUTHEAST KANSAS. THESE TEMPERATURES WILL CONTINUE TO TUMBLE AS THE MORNING WEARS ON. THE NEXT CONCERN IS SOME PRECIPITATION TRYING TO DEVELOP ACROSS SOUTHERN OKLAHOMA. THIS IS ASSOCIATED WITH A WEAK UPPER LEVEL WAVE MOVING THROUGH THAT REGION WHICH IS DISPLAYED ON THE 305K THETA SURFACE. THIS AREA OF LIFT WILL LIFT NORTHEAST INTO SOUTHEAST KANSAS BY MID MORNING WHICH COULD BRING SOME ICY CONDITIONS TO AREAS MAINLY EAST OF THE KANSAS TURNPIKE. QPF AMOUNTS ARE QUESTIONABLE AT THIS POINT...BUT I WOULD NOT SURPRISED IF SOME FOLKS SEE A TENTH TO TWO TENTHS OF AN INCH OF RAIN...BUT IT WILL TAKE A LITTLE FOR THE GROUND TEMPERATURES TO COOL OFF BEFORE ANY SIGNIFICANT ICING HAPPENS. THE NAM-WRF SOLUTION IS EVEN SHOWING SOME LIFT DEVELOP DURING THE AFTERNOON ACROSS EASTERN OKLAHOMA WHICH COULD BRING ANOTHER ROUND OF PRECIPITATION. RIGHT NOW...THIS LOOKS LIKE A FREEZING RAIN SITUATION DUE TO SUCH WARM AIR ALOFT. AT FIRST GLANCE...WE FELT CONFIDENT ENOUGH TO REMOVE THE WINTER WEATHER ADVISORY FOR PORTIONS OF SOUTH CENTRAL KANSAS. HOWEVER...BASED ON THE LATEST RUC/NAM-WRF SOLUTIONS THEY ARE ADVERTISING THE LOW LEVEL FLOW BACKING WHICH WILL INCREASE THE ISENTROPIC LIFT DURING THE AFTERNOON. WE WILL GO AHEAD AND MENTION A FREEZING RAIN ADVISORY FOR AREAS ALONG AND EAST OF THE TURNPIKE WHILE AREAS WEST OF THE TURNPIKE WE WILL KEEP THE WINTER WEATHER ADVISORY GOING THROUGH 00Z. TONIGHT: WE ARE PLANNING ON KEEPING THE WINTER STORM WATCH GOING FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE PERTURBATIONS IN SOUTHWEST FLOW ALOFT. THE NAM IS PICKING UP ON ANOTHER WAVE MOVING THROUGH THE FORECAST AREA TONIGHT WHILE THE GFS/UKMET ARE NOT SHOWING MUCH SUPPORT IN THIS. WE ARE GOING TO PLAY IT SAFE FOR NOW SINCE THERE IS SO MUCH UNCERTAINTY IN THE UPPER LEVEL PATTERN. IF ANYTHING DOES DEVELOP THEN WE COULD SEE MORE MIXED PRECIPITATION DEVELOPING MAINLY IN CENTRAL KANSAS DUE TO COLDER AIR ALOFT WITH MORE FREEZING RAIN AND DRIZZLE DEVELOPING ELSEWHERE. SATURDAY-SUNDAY: LATEST WATER VAPOR LOOP IS SHOWING THE UPPER LEVEL TROF CONTINUING TO DIG. THE LATEST GFS AND UKMET ARE TENDING TO SLOW DOWN THE POSITION OF THIS TROF TOWARDS SUNDAY. THIS WILL TEND TO FAVOR MORE IN THE WAY OF FREEZING RAIN WITH PERIODS OF SLEET ACROSS SOUTH CENTRAL AND SOUTHEAST KANSAS THROUGH SUNDAY. CENTRAL KANSAS COULD STILL SEE SOME SNOW ON SUNDAY...BUT AMOUNTS ARE STILL TOO DIFFICULT TO TELL AT THIS JUNCTURE. MONDAY-TUESDAY: THIS UPPER LEVEL TROF IS EXPECTED TO SETTLE OVER OUR AREA DURING THESE TWO DAYS WHICH WILL KEEP THINGS UNSEASONABLY COLD BUT DRY. COX && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 16 9 22 19 / 70 60 70 80 HUTCHINSON 13 8 20 16 / 50 60 70 80 NEWTON 14 8 21 19 / 60 60 70 80 ELDORADO 17 10 22 18 / 80 60 70 80 WINFIELD-KWLD 20 12 25 20 / 90 60 70 80 RUSSELL 11 6 14 11 / 10 60 70 80 GREAT BEND 11 6 16 13 / 10 60 70 80 SALINA 12 7 16 15 / 20 60 70 80 MCPHERSON 13 8 18 16 / 50 60 70 80 COFFEYVILLE 23 14 26 23 / 100 60 70 80 CHANUTE 19 11 25 21 / 100 60 70 80 IOLA 18 11 25 21 / 100 60 70 80 PARSONS-KPPF 21 12 26 22 / 100 60 70 80 && .ICT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST THIS AFTERNOON FOR KSZ071-072- 095-096-098>100. WINTER STORM WATCH FROM 6 PM CST THIS EVENING THROUGH SUNDAY AFTERNOON FOR KSZ032-033-047>053-067>072-082-083-091>096-098>100. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ051- 052-067-068-082-083-091-092. FREEZING RAIN ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ053- 069-070-093-094. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 310 PM CST FRI JAN 12 2007 ...WINTER RETURNS WITH A VENGEANCE... SHORT TERM... A DIFFICULT FORECAST OVER THE NEXT FEW DAYS AS AN ARCTIC AIR MASS MOVES SOUTH ACROSS THE CWA. THE CHALLENGES WITH THIS FORECAST ARE HOW FAR SOUTH THE FREEZING PRECIPITATION WILL OCCUR AND HOW MUCH WILL ACCUMULATE. THERE IS A GOOD CHANCE FOR PRECIPITATION THIS WEEKEND BUT HOW FAR SOUTH THE ARCTIC FRONT PROGRESSES BEFORE IT STALLS WILL BE THE DETERMINING FACTOR. THE MODELS HAVE BEEN TOO SLOW WITH THE SOUTHWARD PROGRESSION OF THE ARCTIC FRONT...WITH THE RUC/NAM MODELS APPEARING TO HAVE THE BEST HANDLE ON THE ARCTIC FRONT. THE FRONT IS ALREADY ALONG THE I-20 CORRIDOR AND TEMPERATURES ARE FALLING. TEMPERATURES ARE AT OR BELOW FREEZING ACROSS THE NORTHERN BIG COUNTRY AND THE RAIN THAT IS FALLING ACROSS THE BIG COUNTRY WILL CHANGE OVER TO FREEZING RAIN AFTER SUNSET. WITH THE STRONGEST LIFT ON SATURDAY NIGHT AND SUNDAY MORNING EXPECT THE LARGEST FREEZING RAIN ACCUMULATIONS TO OCCUR DURING THIS TIME PERIOD. ACROSS THE BIG COUNTRY IN GENERAL EXPECT ICE ACCUMULATIONS TONIGHT THROUGH SUNDAY TO BE BETWEEN ONE QUARTER TO ONE HALF OF INCH...SOME ISOLATED AREAS COULD SEE ICE ACCUMULATIONS UP TO ONE INCH. ACROSS THE HEARTLAND AND CONCHO VALLEY EXPECT LESS ICE ACCUMULATION TO OCCUR WITH TOTALS SATURDAY NIGHT THROUGH SUNDAY LESS THAN ONE QUARTER OF AN INCH. TEMPERATURES WILL NOT REBOUND QUICKLY SO WHAT ICE THAT ACCUMULATES WILL STAY AROUND THROUGH THE EARLY PART OF NEXT WEEK. LONG TERM... MODELS DIVERGE THE BEGINNING OF THE WEEK WITH THE GFS SHOWING AN UPPER RIDGE BUILDING INTO THE WEST COAST WITH THE MAIN LOBE OF THE UPPER TROUGH DIGGING FROM THE CENTRAL PLAINS INTO THE SOUTHWEST UNDERCUTTING THE ADVANCING WEST COAST RIDGE. GFS EVENTUALLY MERGES THIS FEATURE WITH A WEST COAST TROUGH MOVING SOUTH ALONG THE PACIFIC COAST AND RETROGRADES THE ENTIRE PACKAGE. PREFER THE NAM THAT HAS THE UPPER LEVEL TROUGH AXIS MOVING EAST OF THE AREA LATE SUNDAY AND THE WEST COAST RIDGE BUILDING EAST INTO THE WESTERN STATES. WITH THIS SCENARIO...PRECIPITATION ENDS QUICKER OVER THE FORECAST AREA WITH THE PRECIPITATION SHIELD MOVING EAST AHEAD OF THE UPPER TROUGH BY MONDAY AFTERNOON. TEMPERATURES WILL CLIMB SLOWLY THROUGH THE END OF THE WEEK TO AROUND SEASONAL NORMALS BY THE COMING WEEKEND. PRELIMINARY POINT TEMPS/POPS... ABILENE 27 32 30 31 / 70 60 70 70 SAN ANGELO 31 37 32 40 / 60 60 70 70 JUNCTION 48 53 39 46 / 60 70 70 70 && .SJT WATCHES/WARNINGS/ADVISORIES... ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR CALLAHAN-FISHER- JONES-NOLAN-SHACKELFORD-TAYLOR. WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON FOR CONCHO-IRION-MCCULLOCH-SAN SABA-TOM GREEN. WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH SUNDAY AFTERNOON FOR BROWN-COKE-COLEMAN-RUNNELS-STERLING. ICE STORM WARNING UNTIL 6 PM CST SUNDAY FOR HASKELL-THROCKMORTON. && $$ 28/15 tx