Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/10/13


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
625 PM MST MON DEC 9 2013 .UPDATE... && .SHORT TERM...STRONG AND GUSTY WINDS HAVE DEVELOPED IN THE LOWER AND BASE OF FOOTHILLS WITH A FEW LOCALIZED HIGH WIND GUSTS BETWEEN GOLDEN AND BOULDER. MOST OTHER AREAS ARE MUCH LOWER...GENERALLY IN THE 30-50 MPH RANGE. BEING SO LOCALIZED WILL NOT ISSUE A HIGH WIND WARNING FOR NOW. GOOD MOUNTAIN WAVE SET UP AS 00Z DENVER SOUNDING SHOWED STRONG INVERSION AT 700MB WHILE SURFACE GRADIENT AROUND 12MB ACROSS THE STATE. QG FIELDS ALSO SHOWING VERY STRONG SUBSIDENCE AS RAP SHOWED +50 ON THE QG VERTICAL VELOCITY FIELDS AT 500MB. WILL WATCH THIS CLOSELY THIS EVENING IN CASE OBSERVATIONS SHOW THE STRONGER WINDS BECOME MORE WIDESPREAD. .AVIATION...GUSTY WEST WINDS HAVE NOW SURFACED AT KDEN AND HAVE ADDED STRONGER WINDS AT THE TERMINAL UNTIL 03Z. EXPECT GUSTY WINDS TO CONTINUE AT BJC IN THE 25-40KT RANGE. WINDS WILL GRADUALLY DECREASE IN BOTH LOCATIONS LATER THIS EVENING. && .PREV DISCUSSION... /ISSUED 338 PM MST MON DEC 9 2013/ SHORT TERM...SUBSIDENCE BEHIND THIS MORNING`S WEAK TROUGH COMBINED WITH INCREASING PRESSURE GRADIENT FROM GJT TO DEN AND MIXING TO PRODUCE GUSTY WINDS ACROSS MOUNTAINS AS WELL AS IN AND NEAR FOOTHILLS. LATEST RAP ANALYSIS SHOWING THE MAIN BATCH OF SUBSIDENCE NOW MOVING OVERHEAD. MOST GUSTS WERE AROUND 40 MPH...THOUGH THERE WERE GUSTS AROUND 55 MPH IN WIND PRONE AREAS IN THE FOOTHILLS OF NORTHERN JEFFERSON COUNTY. WINDS WERE LESS FURTHER AWAY FROM THE FOOTHILLS. THE GUSTY WINDS WERE PRODUCING SOME BLOWING SNOW...CONFINED TO OPEN AREAS. THE GUSTY WINDS WILL PERSIST INTO THE EVENING THEN RETREAT INTO THE HIGHER FOOTHILLS BY MIDNIGHT AS MIXING AND SUBSIDENCE WEAKENS. BUT THESE WINDS SHOULD ALSO STRENGTHEN AS CROSS MOUNTAIN FLOW INCREASES TO AROUND 40 KTS. THIS COULD RESULT IN GUSTS AROUND 65 MPH IN WIND PRONE AREAS. NOT EXPECTING THE GUSTS REACHING HIGH WIND CRITERIA OF 75 MPH AT THIS TIME. SOME BLOWING SNOW WILL BE POSSIBLE...ESPECIALLY IN OPEN AREAS. A BIT OF MOISTURE STILL TRAPPED ACROSS THE MOUNTAIN AND THERE MAY BE A FEW LIGHT SNOW SHOWERS OR FLURRIES. OVERNIGHT TEMPERATURES EXPECTED TO FALL INTO THE SINGLE DIGITS ACROSS THE PLAINS WITH BELOW ZERO READINGS IN THE HIGH COUNTRY AND LOW LYING AREAS NEAR LIMON AND GREELEY. TEMPERATURES TO BE WARMER IN AND NEAR FOOTHILLS DUE TO THE DOWNSLOPE WINDS. ON TUESDAY...NORTHWEST FLOW ALOFT TO PREVAIL. THERE WILL BE SOME WARMING DUE TO UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT BASIN AND DOWNSLOPE WINDS ALONG FOOTHILLS. TEMPERATURES ACROSS THE PLAINS TO WARM INTO THE LOWER 30S...WITH UPPER 20S IN THE LOW LYING AREAS. MOUNTAIN AREAS SHOULD WARM INTO THE TEENS BUT GUSTY WINDS WILL KEEP WIND CHILL READINGS BELOW ZERO. GUIDANCE VALUES STILL A BIT OPTIMISTIC WITH THE WARMUP. SOME MOISTURE AND WEAK LIFT MOVES INTO THE NORTHERN MOUNTAINS...ENOUGH FOR A SLIGHT CHANCE OF LIGHT SNOW. ANY ACCUMULATIONS TO BE MINIMAL. LONG TERM...WEATHER THE NEXT WEEK WILL BE DOMINATED BY A RIDGE OVER COLORADO. WEAK RIPPLES COMING NORTH OF US IN WESTERLY FLOW AND A WEAK LOW PASSING WELL SOUTH OF US. ALL OF THESE THINGS CONTINUE TO GET WEAKER WITH SUBSEQUENT MODEL RUNS AND SHOULD NOT HAVE MUCH EFFECT ON OUR WEATHER. THERE WILL BE A CHANCE OF LIGHT SNOW IN THE MOUNTAINS WITH THE TAIL END OF THE NORTHERN SHORT WAVES...AND WEAK SURGES OF COOL AIR FROM THE NORTH AS WELL. THESE WILL COME ABOUT FRIDAY AND AGAIN ON SUNDAY OR MONDAY...BRINGING A LITTLE COOLING...OR DELAYING THE WARMING...EACH DAY. BY THE END OF THE WEEK THE AIR ALOFT WILL BE QUITE WARM...BUT THE LOW LEVELS WILL LAG BEHIND. ALL OF THIS IS WELL COVERED IN THE CURRENT FORECAST AND THE MODEL CONSENSUS LOOKS GOOD. AVIATION...WESTERLY WINDS HAVE PUSHED ACROSS THE AREA AIRPORTS WITH GUSTS AROUND 35 KTS AT KBJC. WINDS MUCH LESS AT KDEN AND KAPA...AROUND 12 KTS. WINDS AT KDEN AND KAPA WILL TRANSITION TO DRAINAGE BY 02Z...REMAINING WESTERLY AT KBJC. SOME GUSTS COULD AGAIN REACH 35 KTS AT KBJC OVERNIGHT. ON TUESDAY...WINDS WILL WEAKEN AND BECOME NORTHWEST BY 17Z...SPEEDS AROUND 8 KTS. VFR TO CONTINUE WITH UNLIMITED CEILINGS. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN LONG TERM....GIMMESTAD AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
420 PM EST SUN DEC 8 2013 .SYNOPSIS... COLD AND HIGH PRESSURE GRADUALLY LIFTS NORTH AND EAST AS LOW PRESSURE LIFTS NORTH FROM THE CAROLINAS TONIGHT...ACROSS SOUTHERN NEW ENGLAND DURING THE DAY MONDAY. MAINLY DRY...BUT UNSEASONABLY COLD AND BLUSTERY WEATHER IS EXPECTED FOR THE REST OF THE UPCOMING WORK WEEK. WE WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR A PERIOD OF LIGHT SNOW ON TUESDAY...MAINLY SOUTH OF THE MASSACHUSETTS TURNPIKE. && .NEAR TERM /UNTIL 8 PM THIS EVENING/... COLD AND DRY HIGH PRESSURE REMAINS RELATIVELY IN CONTROL. PER THE LATEST SURFACE ANALYSIS...THE COLD-AIR DAMMING SIGNATURE IS WELL- EVIDENT THROUGH THE MID-ATLANTIC ALONG THE EASTERN SPINE OF THE APPALACHIAN MOUNTAINS. IT WILL LIKELY TAKE SOME TIME INTO THIS EVENING FOR THE LOW PRESSURE CENTER EVOLVING OFF THE CAROLINA COASTLINE TO BEGIN THE PROCESS OF WARM AIR NORTH AND ERODING THE COLDER AIR IN PLACE. FOLLOWING HRRR TRENDS...EXPECT THE HEAVIEST BANDING OF PRECIPITATION TO REMAIN SOUTH OF THE REGION COLLOCATED WITH THE H85 THERMAL GRADIENT AND REGION OF GREATEST MID-LEVEL CONVERGENCE. WILL KEEP WITH A DRY FORECAST INTO SUNDOWN. && .SHORT TERM /8 PM THIS EVENING THROUGH 6 PM MONDAY/... AN OPEN-WAVE TROUGH ACROSS THE GREAT LAKES REGION HAS BEGUN TO INTERACT WITH THE BROADER SUB-TROPICAL FLOW ACROSS THE EASTERN CONUS. INFLECTION ALONG THE COLLOCATED TIGHT THERMAL GRADIENT HAS SUBSEQUENTLY RESULTED IN A WEAK AREA OF LOW PRESSURE PRESENTLY OFF THE MID-ATLANTIC WHICH WILL DRIFT NORTHEASTWARD ACROSS CAPE COD BRINGING WITH IT A WINTRY MIX OF SNOW...SLEET...AND FREEZING RAIN FOR SOUTHERN NEW ENGLAND DURING THE TIMEFRAME /ESPECIALLY THE MONDAY MORNING COMMUTE/. HAVE GREATER CONFIDENCE WITH COLDER SOLUTIONS. WITH BROAD AGREEMENT AND RUN-TO-RUN CONTINUITY FROM THE ECMWF...PREFER THE MESO-NAM AND WRF-MODEL SOLUTIONS WHICH CAPTURE THE COLD-AIR DAMMING PROCESSES THROUGH THE CONNECTICUT RIVER VALLEY /SEE 1000-850 THICKNESSES/. TRENDS ARE NOTEWORTHY WITHIN THE LATEST HRRR RUNS. BUT OVERALL THERE IS STILL PLENTY OF UNCERTAINTY CONCERNING THERMAL PROFILES AND THE ACCOMPANYING TRANSITION PROCESS OF WINTRY WEATHER TO PLAIN RAIN. THAT BEING SAID...THERE IS A LOT TO CONSIDER. WITH H975 AGEOSTROPHIC FLOW OUT OF THE INTERIOR NORTH WITH A WEAK LOW TRACKING ACROSS THE CAPE...NOT EXPECTING EASTERLY ONSHORE FLOW NORTH OF THE LOW TO SCOUR OUT INTERIOR SURFACE COLD AIR EFFECTIVELY. EXPECT PREVAILING NORTHERLY COLD-AIR DRAINAGE FLOW...JAMMING UP THROUGHOUT INTERIOR VALLEYS /ESPECIALLY THE CT RIVER VALLEY/. 2M FORECASTED TEMPERATURES TAKEN MAINLY FROM MESO-NAM/WRF-MODEL SOLUTIONS. THOUGH THE EASTERLY ONSHORE FLOW WILL RESULT IN A FASTER TRANSITION OF PRECIPITATION TYPES ACROSS EAST COASTAL PLAIN IN THE MORNING...EXPECTING A WINTRY MIX TO LAST LONGER ACROSS THE INTERIOR INTO THE MIDDAY AND POSSIBLY THE AFTERNOON HOURS. UPSTREAM TRENDS ACROSS INTERIOR MID-ATLANTIC SHOW THIS PROCESS ALREADY ONGOING WHICH ADD FURTHER CONFIDENCE THAT COLD-AIR DAMMING OVER THE INTERIOR WILL BE A BIG ISSUE AS TO WINTER WEATHER OUTCOMES. PRECIPITATION AND SNOW/ICE AMOUNTS REMAIN A CHALLENGE...AND LIKELY THERE ARE ALWAYS SURPRISES IN STORE WITH SYSTEMS SUCH AS THESE. CONSIDERING THE AFOREMENTIONED SPATIAL AND TEMPORAL CHALLEGES IN THE PRECIPITATION TRANSITION...IMPACTING ACCUMULATIONS AT THE SURFACE... ANOTHER POINT OF CONCERN IS UPON PRECIPITATION AMOUNTS. EVALUATING THE ATMOSPHERE...FORCING IS MAINLY WITHIN LOW-LEVELS WITH LITTLE INDICATION OF DEEP-LAYER ASCENT ALBEIT SOME BROAD-SCALE DIFFLUENCE ALOFT. YET SREF V-WIND ANOMALIES AT H85 ARE +2 STANDARD-DEVIATIONS AND NOTING UPSTREAM TRENDS OVER THE MID-ATLANTIC...THERE IS THE DISTINCT POSSIBILITY FOR A MESO-SCALE BAND OF SNOW ACROSS SOUTHERN NEW ENGLAND COLLOCATED WITH THE TIGHT H85 THERMAL GRADIENT WHERE STRONG LOW-LEVEL CONVERGENCE IS MODELED TO LIFT THROUGH BETTER SNOW- GROWTH REGIONS. THERE IS SOME SIGNAL WITHIN NEAR-TERM MESOSCALE SOLUTIONS...ALBEIT CHAOTIC. IT IS ENTIRELY PLAUSIBLE TO SEE AREAS IN PROXIMITY TO THE SOUTH-COAST OF SEEING A COUPLE OF INCHES OF SNOW IN A SHORT PERIOD OF TIME DURING THE EARLY ONSET BEFORE TRANSITIONING TO RAIN. AS SUCH...WILL TAKE 1-2 INCH ACCUMULATIONS DOWN TO THE SOUTH-COAST. WILL HAVE 2-4 INCHES FOR PORTIONS OF NORTH AND WEST MA AND SOUTHERN NH. ICE ACCUMULATIONS UP TO A TENTH OF AN INCH EXPECTED ALONG AND EAST OF THE EASTERN COASTAL PLAIN...EAST OF THE I-95/I-495 BELTWAY. TOTAL LIQUID PRECIPITATION AMOUNTS AROUND 0.4 INCHES WITH THE HEAVIEST AMOUNTS JUST OFF THE SOUTH-COAST. EXPECT ACCUMULATIONS TO BEGIN THIS EVENING AND CONTINUE THROUGH THE MORNING COMMUTE. WILL SEE A GRADUAL TRANSITION OF FROZEN P-TYPES BACK INTO THE INTERIOR BEGINNING AROUND 6-8 AM...WITH LOCATIONS ACROSS WESTERN AND NORTHERN MA AND SOUTHERN NH SEEING THE LONGEST PERIOD OF A WINTRY MIX....EAST-COAST TRANSITIONING QUICKEST. HAVE LENGTHENED THE WINTER- WEATHER ADVISORY FOR HARTFORD COUNTY CT WITH THE EXPECTATION OF COLD-AIR DRAINAGE PROCESSES. IMPACTS IN THE WINTER WEATHER ADVISORY...BUT IN BREVITY...EXPECT A MESSY MONDAY MORNING COMMUTE. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * PERIOD OF LIGHT SNOW POSSIBLE SOUTH OF MA PIKE ON TUE * MAINLY DRY AND UNSEASONABLY COLD WED THROUGH FRI * LOW CONFIDENCE FORECAST NEXT WEEKEND DETAILS... MONDAY NIGHT... OTHER THAN PERHAPS A LEFT OVER SPOT SHOWER IN THE EARLY EVENING... DRY WEATHER EXPECTED. A COLD FRONT SWINGS THROUGH THE REGION EARLY IN THE EVENING. TEMPS WILL ACTUALLY RISE ABOVE FREEZING ACROSS PORTIONS OF THE INTERIOR THAT HAVE BEEN JAMMED IN SHALLOW COLD AIR DURING THE DAY MONDAY. THE REASON FOR THIS IS THAT WARMER MID LEVEL AIR WILL BE TEMPORARILY MIXED DOWN...AS WINDS SHIFT TO THE WEST. THIS SHOULD ALLOW ANY LEFTOVER ICY CONDITIONS ON ROADWAYS TO MELT. COLDER AIR WILL FINALLY BEGIN WORKING BACK INTO THE REGION OVERNIGHT...WITH LOWS BY DAYBREAK BACK INTO THE 20S ACROSS THE INTERIOR. THE COASTAL PLAIN SHOULD ONLY SEE LOWS REACH THE LOWER TO MIDDLE 30S. TUESDAY... THE MAIN CONCERN IS THE CHANCES FOR A PERIOD OF LIGHT SNOW ON TUESDAY...MAINLY SOUTH OF THE MA TURNPIKE. A WEAK WAVE OF LOW PRESSURE WILL BE PASSING WELL TO OUR SOUTH...BUT AN APPROACHING SHORTWAVE BACKS THE UPPER LEVEL FLOW. IT PLACES US UNDERNEATH A POTENT JET STREAK WHICH RESULTS IN A PERIOD OF DECENT MID LEVEL LIFT. WILL BE FIGHTING LOW LEVEL DRY AIR SO NOT EXPECTING A LOT OF PRECIP...BUT A PERIOD OF LIGHT SNOW IS STILL POSSIBLE SOUTH OF MA TURNPIKE ESPECIALLY NEAR THE SOUTH COAST. PERHAPS ITS MILD ENOUGH FOR MIXED PRECIP AT THE ONSET ACROSS CAPE/ISLANDS...BUT SHOULD TURN OVER TO ALL LIGHT SNOW. WE MAY EVEN SEE A COATING TO PERHAPS 1 INCH IN A FEW LOCATIONS. THERE IS A LOW PROBABILITY OF A BIT MORE SNOW NEAR THE SOUTH COAST...BUT MOST GUIDANCE DOES NOT SUPPORT THAT AT THIS TIME. WEDNESDAY THROUGH FRIDAY... NORTHWEST FLOW ALOFT WILL RESULT IN UNSEASONABLY COLD WEATHER FOR SOUTHERN NEW ENGLAND. THERE ARE SOME MODEL DISCREPANCIES ON THE TIMING OF REINFORCING SHOTS OF COLD AIR...HENCE UNCERTAINTIES ON WHICH DAY WILL BE THE COLDEST. MAINLY DRY WEATHER DOMINATES OVER THIS TIME PERIOD...BUT CAN/T RULE OUT A BRIEF PASSING FLURRY/SNOW SHOWER WITH SOME MOISTURE STARVED NORTHERN STREAM ENERGY/FRONTAL PASSAGES. IT ALSO WILL BE WINDY AT TIMES...SO IT CERTAINLY WILL FEEL WINTERLIKE. SATURDAY AND SUNDAY... FORECAST CONFIDENCE IS VERY LOW OVER THIS TIME. THE ONE THING WILL HAVE TO WATCH NEXT WEEKEND IS THE TRACK A WAVE OF LOW PRESSURE TO OUR SOUTH. MOST MODELS SUGGEST THAT THE SYSTEM WILL PASS FAR ENOUGH SOUTH TO SPARE OUR REGION OF SIGNIFICANT PRECIP. HOWEVER...SOME MODELS SUGGEST THE LARGE HIGH TO OUR NORTH MAY EVENTUALLY RESULT IN ONSHORE FLOW...BRINGING THE POTENTIAL FOR SOME LIGHT WINTRY PRECIPITATION. OTHER GUIDANCE SUGGESTS SOUTHWEST FLOW ALOFT MAY RESULT IN SOME OVER RUNNING PRECIPITATION. ALL IN ALL...VERY LOW CONFIDENT FORECAST FOR NEXT WEEKEND. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. 21Z UPDATE... NEAR-TERM /THROUGH MONDAY/...HIGH CONFIDENCE ON TRENDS. MODERATE CONFIDENCE ON TIMING OF PRECIPITATION TYPE SPECIFICS AND CIG/VSBY IMPACTS. CIGS LOWERING FROM LOW-END VFR TO MVFR/IFR. INITIAL ONSET OF -SN WITH IFR VSBYS...TRANSITIONING TO -PL/UP/FZRA THEN TO PLAIN RAIN BY MORNING INTO THE AFTERNOON. EXPECT QUICKEST TRANSITION ALONG EAST-COAST TERMINALS...MORE GRADUAL ACROSS THE INTERIOR WITH THE WINTRY MIX HOLDING ON LONGER OVER TERMINALS WITHIN VALLEYS. WITH -SN/PL WENT WITH IFR VSBYS...MVFR VSBYS FOR -FZRA/RA. NORTHERLY FLOW GRADUALLY VEERING EASTERLY THROUGH THE PERIOD WITH GUSTS UP TO AROUND 20 KTS ESPECIALLY ALONG THE COAST. THOUGH EXPECT IN SHELTERED VALLEYS A LIGHT NORTHERLY FLOW TO PREVAIL. CONDITIONS BEGIN TO IMPROVE INTO MONDAY NIGHT. KBOS TAF...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN TIMING OF PRECIPITATION TRANSITIONS. EXPECTING -SN TO QUICKLY TRANSITION TO -RA DURING THE MORNING WITH ONSHORE EASTERLY FLOW. KBDL TAF...HIGH CONFIDENCE IN TRENDS. LOW CONFIDENCE IN TIMING OF PRECIPITATION TRANSITIONS. -SN WILL GRADUALLY TRANSITION TO A WINTRY MIX...BUT THAT MIX MAY HOLD LONGER WITH SHALLOW COLD AIR BELOW-FREEZING OVER THE TERMINAL. LIGHT NORTHERLY FLOW. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY... MONDAY NIGHT...MODERATE TO HIGH CONFIDENCE. LEFT OVER MVFR-IFR CONDITIONS EARLY IN THE EVENING IMPROVE TO VFR BEHIND A COLD FRONT. TUESDAY...LOW CONFIDENCE. A PERIOD OF MVFR-IFR CONDITIONS POSSIBLE SOUTH OF THE MA TURNPIKE IN A ROUND OF LIGHT SNOW. OTHERWISE...VFR CONDITIONS FOR THE REST OF THE TIME. WEDNESDAY THROUGH FRIDAY...MODERATE TO HIGH CONFIDENCE. VFR CONDITIONS DOMINATE WITH GUSTY WNW WINDS AT TIMES. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /THROUGH MONDAY/...HIGH CONFIDENCE. NORTHERLY WINDS OVER THE WATERS WILL VEER EAST-SOUTHEASTERLY WITH TIME GUSTING 25 TO 30 KTS DURING THE DAY MONDAY AS AN AREA OF LOW PRESSURE CROSSES INTO SOUTHERN NEW ENGLAND. WITH THE LOW/S PASSAGE EXPECT WINDS TO BACK MORE SOUTHERLY. PROLONGED PERIOD OF FETCH WILL RESULT IN SEAS OF 6 TO 8 FEET ACROSS THE OUTER WATERS IMPACTING THE EAST- FACING ATLANTIC BEACHES. SMALL CRAFT ADVISORIES IN EFFECT FOR ALL LOCATIONS EXCEPT INNER BAYS. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. THE GENERAL IDEA IS THAT THE PASSAGE OF A COUPLE OF STRONG COLD FRONTS WILL RESULT IN PERSISTENT WEST TO NORTHWEST WINDS OVER THIS TIME. GIVEN THE STRONG COLD ADVECTION OVER THE WATERS...SCA WIND GUSTS ARE EXPECTED OVER MUCH OF THIS TIME PERIOD OVER THE OPEN WATERS. WE MAY EVEN SEE A BRIEF GALE FOR A TIME ON WEDNESDAY. THERE ALSO WILL BE LULLS IN THE WIND...BUT TIMING THAT THIS FAR OUT IS IMPOSSIBLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST MONDAY FOR CTZ002>004. MA...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST MONDAY FOR MAZ013-017. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY FOR MAZ002>005-008>012-014-026. NH...NONE. RI...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST MONDAY FOR RIZ001>004-006. MARINE...SMALL CRAFT ADVISORY FROM 5 AM TO 1 PM EST MONDAY FOR ANZ231>234. SMALL CRAFT ADVISORY FROM 3 AM TO 6 PM EST MONDAY FOR ANZ235- 237-254>256. SMALL CRAFT ADVISORY FROM 7 AM TO 6 PM EST MONDAY FOR ANZ250. SMALL CRAFT ADVISORY FROM 7 AM TO 1 PM EST MONDAY FOR ANZ251. && $$ SYNOPSIS...FRANK/SIPPRELL NEAR TERM...SIPPRELL SHORT TERM...SIPPRELL LONG TERM...FRANK AVIATION...FRANK/SIPPRELL MARINE...FRANK/SIPPRELL
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
936 PM EST MON DEC 9 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM IS STARTING TO FORM OVER THE CAROLINAS. IT WILL MOVE NORTHEAST OUT TO SEA TUESDAY AFTERNOON AND YANK IN COLDER AIR BEHIND IT TUESDAY NIGHT. HIGH PRESSURE WILL THEN BUILD INTO THE REGION FROM THE WEST DURING MID AND LATE WEEK BEFORE SHIFTING INTO THE WESTERN ATLANTIC SATURDAY. LOW PRESSURE AND A NEW COLD FRONT ARE SLATED TO MOVE ACROSS THE MID ATLANTIC STATES LATE SATURDAY. CANADIAN HIGH PRESSURE SHOULD FOLLOW...ARRIVING IN THE NORTHEAST UNITED STATES EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... NO BIG CHANGES WILL BE MADE WITH THIS UPDATE. OVERALL THE NOD TO THE MODEL THAT IS VERIFYING THE BEST WITH THE MASS FIELDS OFF THE 00Z SOUNDINGS AND 00Z SFC ANALYSIS GOES TO THE ECMWF. THE WRF-NMMB OVERALL WAS SLOW. IF ANYTHING FCST ERRORS AT 925MB AND 850MB WERE AROUND 1C TOO WARM, SO TRENDING TOWARD LESS MIXING POTENTIAL. WE ARE JUST GETTING INTO THE RAP AND HRRR`S TIME FRAME AND THEY ARE SHOWING MULTIPLE BANDING POTENTIAL ON TUESDAY IN BOTH PA AND NJ. THE ECMWF AND THE CANADIAN MODEL OUTPUTS FAVOR NJ AND DE MORE SO THAN MD AND PA. NEVERTHELESS ALL OF THE MODELS ARE SHOWING A QUICK HITTING SNOW EVENT WITH A COUPLE OF HOURS OF HEAVY SNOW WHERE THESE BANDS DEVELOP. SREF MEAN SNOWFALL FOR PHL HAS SETTLED IN AT 3.6 INCHES. SREF SNOWFALL POPS DO FAVOR THE HIGHEST AMOUNTS EAST OF PA. IN THE INTERIM, LAPS FCST SOUNDINGS ARE SHOWING PLENTY OF DRY AIR AND WIND JUST ABOVE THE BOUNDARY LAYER. THE FORMER WILL EVAP COOL THE +6C AIR OVER PHL AT 800MB TO SNOW WHILE THE LATTER SHOULD HELP DISPERSE THE FOG OVERNIGHT. WE DID NOT MAKE ANY BIG CHANGES TO TEMPS AND DEW POINTS. GIVEN THAT THE PCPN IS RACING OUT OF MISSISSIPPI, WE KEPT THE PRESENT TIMING AS IT LOOKS AS THOUGH PCPN SHOULD ADVANCE AND DEVELOP QUICKLY COME TUESDAY MORNING. WE`LL BE IN A LULL MOST OF TONIGHT, BETWEEN YESTERDAY`S SNOW AND WHAT`S TO COME TOMORROW. IMPACTS TONIGHT WILL BE ASSOCIATED WITH FOG AND RESTRICTIVE VISIBILITIES AND SUB-FREEZING TEMPERATURES THAT COULD REFREEZE WHAT`S CURRENTLY ON THE GROUND. TEMPERATURES WILL FALL INTO THE LOWER 20S ACROSS THE NORTHWEST ZONES AND INTO THE UPPER 20S ELSEWHERE. PRECIPITATION WILL BE REENTERING THE PICTURE TOMORROW MORNING. THINGS COULD START TO RAMP UP PRIOR TO 6AM. SOUNDINGS SUGGEST ALL SNOW AT THE ONSET EXCEPT FOR OUR SOUTHERN COUNTIES WHERE SOME FREEZING RAIN AND SLEET IS POSSIBLE. THE MORNING RUSH COULD BE IMPACTED, ALTHOUGH IT APPEARS, AT LEAST AT THIS TIME, THAT WHEN YOU GET NORTH OF DELMARVA, THE ONSET OF PRECIPITATION WILL COMMENCE DURING THE SECOND HALF OF THE COMMUTE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES HAVE BEEN ISSUED. ALTHOUGH BANDING PREDICTABILITY IS FAIRLY LOW, MODELS ARE POINTING TO THE I95 CORRIDOR AT THIS TIME. H8-H7 FORCING IS IN PLACE TOMORROW MORNING AS WELL OMEGA. DECENT SNOW GROWTH IS FORECAST AND WE`RE UNDER THE RIGHT REAR OF THE H3 JET. THE FEELING IS...THERE WILL BE AT LEAST MODERATE SNOW FOR A FEW HOURS THAT WILL COMPENSATE FOR A DAYTIME SNOWFALL WITH TEMPERATURES NEAR FREEZING. WE LIKE 3 TO 5 INCHES ACROSS THE I95 CORRIDOR AND THAT`S WHAT IS IN THE WSW. OUR GRAPHICS ON THE WEB WILL DISPLAY 4 TO 6 INCHES, WITH 3 TO 5 NOT BEING AN OPTION. LESS AMOUNTS SHOULD FALL ACROSS THE FAR NORTHWESTERN ZONES, THE FAR SOUTHERN ZONES AND RIGHT ALONG THE COAST. THE GFS QPF IS ON THE HIGH SIDE OF THE SPECTRUM WHILE THE EURO IS ON THE LOWER SIDE. WE`RE IN THE MIDDLE. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... 500MB: A BROAD TROUGH IN EASTERN UNITED STATES SHARPENS UP A BIT THURSDAY AS SHORT WAVES MOVE THROUGH THE BASE OF THE TROUGH. RIDGING FOLLOWS FRIDAY AND THEN WE WAIT TO SEE HOW THE MID WEEK CLOSED LOW NEAR BAHA CALIFORNIA INTERACTS WITH THE NORTHERN STREAM FOR NEXT WEEKEND. LOTS OF UNCERTAINTY IN THE MODELS FOR NEXT WEEKEND WHICH INCLUDES TEMPS...PTYPE AND STORM TRACK. TROUGHING DEVELOPING IN THE EASTERN USA MAKES IT PROBABLE THAT SOME SORT OF PRECIPITATION SHOULD DEVELOP HERE NEXT WEEKEND. TEMPERATURES: MUCH BELOW NORMAL COLD FOR PORTIONS OF THIS EXTENDED PERIOD WITH CALENDAR DAY AVERAGE VALUES EXPECTED TO BE 10 DEGREES OR MORE COLDER THAN NORMAL WEDNESDAY THROUGH FRIDAY AND POSSIBLY AGAIN NEXT MONDAY WITH FRIDAYS TEMPERATURES POSSIBLY 15 DEGREES BELOW NORMAL! THE MILDEST DAYS SHOULD BE SATURDAY AND OR SUNDAY. FORECAST BASIS... TUE NIGHT-WED NIGHT IS A 50 50 BLEND OF THE 12Z/9 GFS/NAM MOS. THURSDAY IS 100 PCT 12Z/9 GFS MOS AND THEN THU NIGHT- NEXT MONDAY IS THE 1522Z/9 WPC EXTENDED GRIDS. THIS DATA IS CHECKED AGAINST THE 12Z/9 ECMWF...MODIFIED AND NOTED IN THE DAILIES WHEN SIGNIFICANT. THE 09Z/9 SREF WAS CHECKED FOR POPS WITHIN ITS FORECAST RANGE THE 12Z/9 GEFS 6HR POPS FOR .05 WERE CHECKED FOR THE EXTENDED GRIDS THURSDAY-MONDAY. THE DAILIES BELOW... TUE NIGHT...CLEARING AND COLDER WITH FREEZE UP OF THE TUESDAY SNOW EVENT. WINTRY LOOKING NIGHT-SCAPE. A BIT OF AN ADDED WIND CHILL TOO! WEDNESDAY AND THURSDAY...POTENTIAL FOR BURSTS OF SNOW SHOWERS NEAR AND NORTH OF I80 IN NE PA AND NW NJ AS THE SOUTHERN EXTENT OF WINDEX EVENTS ARE SUGGESTED BY THE GUIDANCE TO GRAZE THE NORTHERN PORTION OF OUR FORECAST AREA. THE SHORT WAVES ARE SENDING IN BURSTS OF COLDER AIR IN GENERAL WNW FLOW AND YOU COULD ARGUE THAT A SECONDARY COLD FRONTAL PASSAGE CAN OCCUR WEDNESDAY NIGHT. BLUSTERY DAY TIMES. OVERALL SOUTH OF I80...P/C...POSSIBLY A FLURRY OR 2. THE WCI MAY DROP TO 10 BELOW ZERO IN THE POCONOS THU NIGHT. FRIDAY...COLD INTERLUDE WITH INCREASING CLOUDS POSSIBLE? NEXT WEEKEND...POTENTIAL FOR PERIODS OF WINTRY PCPN...ESPECIALLY SATURDAY...DEPENDING ON SFC LOW EVOLUTION ON A NEW COLD FRONT CROSSING EASTWARD FROM THE APPALACHIANS. RIGHT NOW OUR FCST IS HINGED COMPLETELY ON WPC GUIDANCE. ITS CATEGORICAL THAT IT WILL PRECIPITATE BUT CONFIDENCE ON DETAILS INCLUDING TEMPS AND PTYPE IS WELL BELOW AVERAGE.THE FCST DRAWN UP FOCUSES PCPN ON SATURDAY ENDING SATURDAY EVENING. NEXT MONDAY...BLUSTERY AND COLD...AT LEAST TO START. THE WCI MAY DROP TO 10 BELOW IN THE POCONOS EARLY MONDAY BUT CONFIDENCE ON COLD TEMPS MONDAY IS LESS THAN THE HIGH CONFIDENCE FCST FOR WEDNESDAY-FRIDAY. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. OVERNIGHT...THE 00Z TAFS HAVE BEEN ISSUED. IT APPEARS THE THE FOG AND LOWER CLOUDS MAY REMAIN FOR A BIT LONGER THAN EARLIER FCST. SOME BREAKS ARE BEGINNING TO SHOW UP ON THE 11U-39.U SATELLITE IMAGES ACROSS THE DELMARVA AND SRN NJ. WE PUSHED BACK THE RETURN TO HIGHER CONDITIONS TO 05-06Z FOR MANY SITES. TUESDAY...MVFR WILL QUICKLY TRANSITION INTO IFR AS SNOW SETTLES IN ACROSS THE TERMINALS. WE TRIED TO REFINE THIS SOMEWHAT IN THE 00Z TAFS AND INDICATED THAT IT MAY BE A HOUR OR SO EARLIER THAN BEFORE. A PERIOD OF LIFR IS POSSIBLE IN SOME HEAVIER SNOW. SOME IMPROVEMENT, MAYBE BACK TO VFR, POSSIBLE LATER IN THE DAY. OUTLOOK... TUESDAY NIGHT...VFR NW WIND GUST TO 20 KT. CONFIDENCE ABOVE AVG. WEDNESDAY - THURSDAY...VFR SCT-BKN AOA 3500 FT. CHANCE OF A FLURRY EXCEPT A FEW PERIODS OF MVFR OR IFR CONDS IN SNOW SHOWERS AR POSSIBLE IN THE POCONOS. W-NW WIND G 20-25 KT EACH AFTN. CONFIDENCE ABOVE AVERAGE. I DID RAISE 12Z/9 NCEP MOS GUIDANCE BY ABOUT 4 DEGREES PRIMARILY BECAUSE OF STILL RELATIVELY MILD 850 TEMPS AND THE 12Z/9 UK AND EC 2M TEMPS. FRIDAY...VFR CIGS. WIND TURNING WEST OR SOUTHWEST IN THE AFTN. SATURDAY...MVFR OR IFR CONDS PROBABLE IN PCPN. && .MARINE... TONIGHT...NO HEADLINES WITH DIMINISHING WINDS AND SEAS IN THE 2 TO 4 FOOT RANGE. TUESDAY...BOTH NORTHWEST WINDS AND SEAS WILL BEGIN TO BUILD LATER TOMORROW. GUIDANCE SUGGESTS THAT SCA CONDITIONS WILL BE BACK IN PLACE LATE TOMORROW AFTERNOON OR EARLY TOMORROW EVENING. OUTLOOK... TUESDAY NIGHT - THURSDAY...A FAIRLY TIGHT GRADIENT WILL PERSIST WITH PERIODS OF GUSTY WINDS TO 25 KT AND END OF WESTERLY FETCH SEAS ON THE ATLANTIC NEAR 5 FT. WE MAY HAVE NEAR GALE FORCE GUSTS TUESDAY NIGHT AND WEDNESDAY MORNING, ESPECIALLY ACROSS THE NORTHERN OCEAN WATERS. SCA HAS BEEN STARTED. AN EXTENSION PROBABLE AND IT MAY NEED AN UPGRADE TO A MARGINAL GALE IN LATER FCST FOR A PTN OF TUE NIGHT. FRIDAY...WINDS AND SEAS SHOULD SUBSIDE BELOW SMALL CRAFT ADVISORY LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION AND REMAIN BELOW AS WE END THE WORK WEEK. SATURDAY...AN SCA IS POSSIBLE. THERE IS MODEL SPREAD ON THE SOLUTIONS BUT ITS EVEN POSSIBLE WE`LL NEED A SLY GALE FOR A PTN OF THE ATLANTIC WATERS. THIS PART OF THE FCST IS VERY LOW CONFIDENCE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR PAZ060>062-101-103-105. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR PAZ070- 071-102-104-106. NJ...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR NJZ007>010-012>014-020>027. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR NJZ015>019. DE...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR DEZ002>004. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR DEZ001. MD...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR MDZ012-015-019-020. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR MDZ008. MARINE...SMALL CRAFT ADVISORY FROM 5 PM TUESDAY TO 6 AM EST WEDNESDAY FOR ANZ430-431-450>455. && $$ SYNOPSIS...DRAG NEAR TERM...GIGI/KRUZDLO SHORT TERM...KRUZDLO LONG TERM...DRAG AVIATION...DRAG/O`HARA MARINE...DRAG/KRUZDLO
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
626 PM EST MON DEC 9 2013 .SYNOPSIS... LOW PRESSURE EAST OF LONG ISLAND IS MOVING NORTHEAST WHILE A NEW AREA OF LOW PRESSURE FORMS IN NORTH CAROLINA TONIGHT. THAT NORTH CAROLINA LOW ZIPS NORTHEAST OUT TO SEA TUESDAY AFTERNOON YANKING IN COLDER AIR BEHIND IT TUESDAY NIGHT. HIGH PRESSURE WILL THEN BUILD INTO THE REGION FROM THE WEST DURING MID AND LATE WEEK BEFORE SHIFTING INTO THE WESTERN ATLANTIC SATURDAY. LOW PRESSURE AND A NEW COLD FRONT ARE SLATED TO MOVE ACROSS THE MID ATLANTIC STATES LATE SATURDAY. CANADIAN HIGH PRESSURE SHOULD FOLLOW...ARRIVING IN THE NORTHEAST UNITED STATES EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... SHORT TERM UPDATE MAINLY ADDRESSED THE MENTION OR LACK THEREOF OF FOG INTO EARLY THIS EVENING. A WESTERLY GRADIENT OVER OUR CWA HAS HELPED THIN THE FOG. BASED ON THE LATEST HRRR AND RAP WE PUSHED BACK THE ONSET OF POPS A COUPLE OF HOURS. WILL TAKE A CLOSER LOOK AS TO HOW THE MODELS ARE VERIFYING AT 00Z. WE`LL BE IN A LULL MOST OF TONIGHT, BETWEEN YESTERDAY`S SNOW AND WHAT`S TO COME TOMORROW. IMPACTS TONIGHT WILL BE ASSOCIATED WITH FOG AND RESTRICTIVE VISIBILITIES AND SUB-FREEZING TEMPERATURES THAT COULD REFREEZE WHAT`S CURRENTLY ON THE GROUND. TEMPERATURES WILL FALL INTO THE LOWER 20S ACROSS THE NORTHWEST ZONES AND INTO THE UPPER 20S ELSEWHERE. PRECIPITATION WILL BE REENTERING THE PICTURE TOMORROW MORNING. THINGS COULD START TO RAMP UP PRIOR TO 6AM. SOUNDINGS SUGGEST ALL SNOW AT THE ONSET EXCEPT FOR OUR SOUTHERN COUNTIES WHERE SOME FREEZING RAIN AND SLEET IS POSSIBLE. THE MORNING RUSH COULD BE IMPACTED, ALTHOUGH IT APPEARS, AT LEAST AT THIS TIME, THAT WHEN YOU GET NORTH OF DELMARVA, THE ONSET OF PRECIPITATION WILL COMMENCE DURING THE SECOND HALF OF THE COMMUTE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES HAVE BEEN ISSUED. ALTHOUGH BANDING PREDICTABILITY IS FAIRLY LOW, MODELS ARE POINTING TO THE I95 CORRIDOR AT THIS TIME. H8-H7 FORCING IS IN PLACE TOMORROW MORNING AS WELL OMEGA. DECENT SNOW GROWTH IS FORECAST AND WE`RE UNDER THE RIGHT REAR OF THE H3 JET. THE FEELING IS...THERE WILL BE AT LEAST MODERATE SNOW FOR A FEW HOURS THAT WILL COMPENSATE FOR A DAYTIME SNOWFALL WITH TEMPERATURES NEAR FREEZING. WE LIKE 3 TO 5 INCHES ACROSS THE I95 CORRIDOR AND THAT`S WHAT IS IN THE WSW. OUR GRAPHICS ON THE WEB WILL DISPLAY 4 TO 6 INCHES, WITH 3 TO 5 NOT BEING AN OPTION. LESS AMOUNTS SHOULD FALL ACROSS THE FAR NORTHWESTERN ZONES, THE FAR SOUTHERN ZONES AND RIGHT ALONG THE COAST. THE GFS QPF IS ON THE HIGH SIDE OF THE SPECTRUM WHILE THE EURO IS ON THE LOWER SIDE. WE`RE IN THE MIDDLE. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... 500MB: A BROAD TROUGH IN EASTERN UNITED STATES SHARPENS UP A BIT THURSDAY AS SHORT WAVES MOVE THROUGH THE BASE OF THE TROUGH. RIDGING FOLLOWS FRIDAY AND THEN WE WAIT TO SEE HOW THE MID WEEK CLOSED LOW NEAR BAHA CALIFORNIA INTERACTS WITH THE NORTHERN STREAM FOR NEXT WEEKEND. LOTS OF UNCERTAINTY IN THE MODELS FOR NEXT WEEKEND WHICH INCLUDES TEMPS...PTYPE AND STORM TRACK. TROUGHING DEVELOPING IN THE EASTERN USA MAKES IT PROBABLE THAT SOME SORT OF PRECIPITATION SHOULD DEVELOP HERE NEXT WEEKEND. TEMPERATURES: MUCH BELOW NORMAL COLD FOR PORTIONS OF THIS EXTENDED PERIOD WITH CALENDAR DAY AVERAGE VALUES EXPECTED TO BE 10 DEGREES OR MORE COLDER THAN NORMAL WEDNESDAY THROUGH FRIDAY AND POSSIBLY AGAIN NEXT MONDAY WITH FRIDAYS TEMPERATURES POSSIBLY 15 DEGREES BELOW NORMAL! THE MILDEST DAYS SHOULD BE SATURDAY AND OR SUNDAY. FORECAST BASIS... TUE NIGHT-WED NIGHT IS A 50 50 BLEND OF THE 12Z/9 GFS/NAM MOS. THURSDAY IS 100 PCT 12Z/9 GFS MOS AND THEN THU NIGHT- NEXT MONDAY IS THE 1522Z/9 WPC EXTENDED GRIDS. THIS DATA IS CHECKED AGAINST THE 12Z/9 ECMWF...MODIFIED AND NOTED IN THE DAILIES WHEN SIGNIFICANT. THE 09Z/9 SREF WAS CHECKED FOR POPS WITHIN ITS FORECAST RANGE THE 12Z/9 GEFS 6HR POPS FOR .05 WERE CHECKED FOR THE EXTENDED GRIDS THURSDAY-MONDAY. THE DAILIES BELOW... TUE NIGHT...CLEARING AND COLDER WITH FREEZE UP OF THE TUESDAY SNOW EVENT. WINTRY LOOKING NIGHT-SCAPE. A BIT OF AN ADDED WIND CHILL TOO! WEDNESDAY AND THURSDAY...POTENTIAL FOR BURSTS OF SNOW SHOWERS NEAR AND NORTH OF I80 IN NE PA AND NW NJ AS THE SOUTHERN EXTENT OF WINDEX EVENTS ARE SUGGESTED BY THE GUIDANCE TO GRAZE THE NORTHERN PORTION OF OUR FORECAST AREA. THE SHORT WAVES ARE SENDING IN BURSTS OF COLDER AIR IN GENERAL WNW FLOW AND YOU COULD ARGUE THAT A SECONDARY COLD FRONTAL PASSAGE CAN OCCUR WEDNESDAY NIGHT. BLUSTERY DAY TIMES. OVERALL SOUTH OF I80...P/C...POSSIBLY A FLURRY OR 2. THE WCI MAY DROP TO 10 BELOW ZERO IN THE POCONOS THU NIGHT. FRIDAY...COLD INTERLUDE WITH INCREASING CLOUDS POSSIBLE? NEXT WEEKEND...POTENTIAL FOR PERIODS OF WINTRY PCPN...ESPECIALLY SATURDAY...DEPENDING ON SFC LOW EVOLUTION ON A NEW COLD FRONT CROSSING EASTWARD FROM THE APPALACHIANS. RIGHT NOW OUR FCST IS HINGED COMPLETELY ON WPC GUIDANCE. ITS CATEGORICAL THAT IT WILL PRECIPITATE BUT CONFIDENCE ON DETAILS INCLUDING TEMPS AND PTYPE IS WELL BELOW AVERAGE.THE FCST DRAWN UP FOCUSES PCPN ON SATURDAY ENDING SATURDAY EVENING. NEXT MONDAY...BLUSTERY AND COLD...AT LEAST TO START. THE WCI MAY DROP TO 10 BELOW IN THE POCONOS EARLY MONDAY BUT CONFIDENCE ON COLD TEMPS MONDAY IS LESS THAN THE HIGH CONFIDENCE FCST FOR WEDNESDAY-FRIDAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. OVERNIGHT...THE 00Z TAFS HAVE BEEN ISSUED. IT APPEARS THE THE FOG AND LOWER CLOUDS MAY REMAIN FOR A BIT LONGER THAN EARLIER FCST. SOME BREAKS ARE BEGINNING TO SHOW UP ON THE 11U-39.U SATELLITE IMAGES ACROSS THE DELMARVA AND SRN NJ. WE PUSHED BACK THE RETURN TO HIGHER CONDITIONS TO 05-06Z FOR MANY SITES. TUESDAY...MVFR WILL QUICKLY TRANSITION INTO IFR AS SNOW SETTLES IN ACROSS THE TERMINALS. WE TRIED TO REFINE THIS SOMEWHAT IN THE 00Z TAFS AND INDICATED THAT IT MAY BE A HOUR OR SO EARLIER THAN BEFORE. A PERIOD OF LIFR IS POSSIBLE IN SOME HEAVIER SNOW. SOME IMPROVEMENT, MAYBE BACK TO VFR, POSSIBLE LATER IN THE DAY. OUTLOOK... TUESDAY NIGHT...VFR NW WIND GUST TO 20 KT. CONFIDENCE ABOVE AVG. WEDNESDAY - THURSDAY...VFR SCT-BKN AOA 3500 FT. CHANCE OF A FLURRY EXCEPT A FEW PERIODS OF MVFR OR IFR CONDS IN SNOW SHOWERS AR POSSIBLE IN THE POCONOS. W-NW WIND G 20-25 KT EACH AFTN. CONFIDENCE ABOVE AVERAGE. I DID RAISE 12Z/9 NCEP MOS GUIDANCE BY ABOUT 4 DEGREES PRIMARILY BECAUSE OF STILL RELATIVELY MILD 850 TEMPS AND THE 12Z/9 UK AND EC 2M TEMPS. FRIDAY...VFR CIGS. WIND TURNING WEST OR SOUTHWEST IN THE AFTN. SATURDAY...MVFR OR IFR CONDS PROBABLE IN PCPN. && .MARINE... TONIGHT...NO HEADLINES WITH DIMINISHING WINDS AND SEAS IN THE 2 TO 4 FOOT RANGE. TUESDAY...BOTH NORTHWEST WINDS AND SEAS WILL BEGIN TO BUILD LATER TOMORROW. GUIDANCE SUGGESTS THAT SCA CONDITIONS WILL BE BACK IN PLACE LATE TOMORROW AFTERNOON OR EARLY TOMORROW EVENING. OUTLOOK... TUESDAY NIGHT - THURSDAY...A FAIRLY TIGHT GRADIENT WILL PERSIST WITH PERIODS OF GUSTY WINDS TO 25 KT AND END OF WESTERLY FETCH SEAS ON THE ATLANTIC NEAR 5 FT. WE MAY HAVE NEAR GALE FORCE GUSTS TUESDAY NIGHT AND WEDNESDAY MORNING, ESPECIALLY ACROSS THE NORTHERN OCEAN WATERS. SCA HAS BEEN STARTED. AN EXTENSION PROBABLE AND IT MAY NEED AN UPGRADE TO A MARGINAL GALE IN LATER FCST FOR A PTN OF TUE NIGHT. FRIDAY...WINDS AND SEAS SHOULD SUBSIDE BELOW SMALL CRAFT ADVISORY LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION AND REMAIN BELOW AS WE END THE WORK WEEK. SATURDAY...AN SCA IS POSSIBLE. THERE IS MODEL SPREAD ON THE SOLUTIONS BUT ITS EVEN POSSIBLE WE`LL NEED A SLY GALE FOR A PTN OF THE ATLANTIC WATERS. THIS PART OF THE FCST IS VERY LOW CONFIDENCE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR PAZ060>062-101-103-105. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR PAZ070- 071-102-104-106. NJ...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR NJZ007>010-012>014-020>027. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR NJZ015>019. DE...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR DEZ002>004. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR DEZ001. MD...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR MDZ012-015-019-020. WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR MDZ008. MARINE...SMALL CRAFT ADVISORY FROM 5 PM TUESDAY TO 6 AM EST WEDNESDAY FOR ANZ430-431-450>455. && $$ SYNOPSIS...DRAG NEAR TERM...GIGI/KRUZDLO SHORT TERM...KRUZDLO LONG TERM...DRAG AVIATION...DRAG/O`HARA/KRUZDLO MARINE...DRAG/KRUZDLO
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
103 PM EST SUN DEC 8 2013 .SYNOPSIS... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND BY THIS EVENING. A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT LAKES REGION THROUGH TODAY AND MONDAY, DRAGGING A COLD FRONT THROUGH OUR AREA LATE MONDAY. MEANWHILE, A LOW PRESSURE SYSTEM WILL DEVELOP AND MOVE UP ALONG THE MIDDLE ATLANTIC COAST ON MONDAY. A SECONDARY FRONT WILL MOVE THROUGH THE REGION LATE TUESDAY INTO WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION FROM THE WEST ON WEDNESDAY BEFORE SHIFTING EAST OF THE AREA AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN EXTENSIVE SURFACE AND UPPER AIR ANALYSIS REVEALS RATHER ROBUST LOW-LEVEL WAA ACROSS PORTIONS OF THE MID ATLANTIC. TO THE NORTH OF THIS ZONE, A TIGHTENING AREA OF WEST TO EAST ORIENTATED FRONTOGENETIC FORCING IS OCCURRING. THIS FORCING IS SEEN IN THE RADAR DATA AS A BANDED FEATURE ACROSS NORTHERN MARYLAND TO PORTIONS OF SOUTHERN NEW JERSEY. THERE APPEARS TO BE SOME SLANTWISE INSTABILITY PLAYING A ROLE ALONG WITH SIGNIFICANT ISENTROPIC UPGLIDE COMBINING WITH THE SNOW GROWTH REGION. THIS IS PRODUCING SNOWFALL RATES OF 1-2 INCHES PER HOUR WITH SOME AREAS UNDER THE BAND REPORTING 4-4.5 INCHES OF SNOW ALREADY. THE VISIBLE SATELLITE IMAGERY HAS SHOWN SOME CONVECTIVE NATURE AT TIMES TO THE CLOUD FEATURES WITH THIS BAND. BASED ON THIS AND ALSO RADAR TRENDS, A WINTER STORM WARNING WAS ISSUED FOR THE COUNTIES BEING AFFECT BY THE BANDING. THE ADVISORY WAS EXPANDED TO THE REST OF THE AREA AS ROADWAYS WILL BECOME OR ALREADY HAVE BECOME HAZARDOUS. THE LATEST HRRR HAS THIS FEATURE PLACED RATHER WELL SO FAR AND IT CONTINUES TO SLIDE IT NORTHEASTWARD ACROSS PHILADELPHIA AND PORTIONS OF SOUTHERN NEW JERSEY. FARTHER NORTH, WEAKER FORCING SO FAR AND DRIER AIR IS PREVENTING THE SNOW FROM SHIFTING NORTHWARD. THE DRY AIR IS EXPECTED TO GRADUALLY GIVE WAY DURING THE REST OF THE AFTERNOON, ALLOWING SNOW TO BREAK OUT FARTHER TO THE NORTH. THE GRIDS WERE UPDATED TO INCREASE SNOW AMOUNTS ESPECIALLY FOR THE AREA BEING AFFECTED BY THE BANDING FEATURE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... HOWEVER, AS WAA INCREASES THRU THE NIGHT, THE PRECIP WILL BEGIN TO MIX AND EVENTUALLY CHANGE TO ALL RAIN FROM SE TO NW. THE GFS IS THE WARMEST/FASTEST MDL WITH THIS TRANSITION. THE NAM/WRF AND ECMWF ARE A BIT SLOWER BUT STILL HAVE THE CHANGEOVER REACHING THE I-95 CORRIDOR SHORTLY AFTER MIDNIGHT. FURTHER AND W, THE WINTRY PRECIP WILL HANG ON LONGER. CURRENT THINKING IS THE GFS IS TOO WARM/TOO QUICK WITH THE TRANSITION. IT IS STILL PSBL THERE COULD BE A PD OF FZRA ALG THE I-95 CORRIDOR, BUT CONFIDENCE IS LOW ON THIS OCCURRENCE SO NO HEADLINES ARE BEING ISSUED FOR NOW. IF THE GFS IS CORRECT, THEY WILL LIKELY NOT BE NEEDED. IF MORE SLEET OCCURS IN THE TRANSITION, THEY MAY NOT BE NEEDED EITHER. BY MON MRNG, ALL BUT THE FAR N AND W SHOULD BE RAIN. TEMPS WILL RISE OVERNIGHT AS THE WAA KICKS IN. THIS IS DEFINITELY A TRICKY TEMP DAY (AND NIGHT) AND A COUPLE OF DEGREES MAKES A WORLD OF DIFFERENCE! && .LONG TERM /MONDAY THROUGH SATURDAY/... THINGS SHOULD BEGIN TO WIND DOWN BY MONDAY MORNING WITH JUST A FEW ISSUES LEFT LINGERING ACROSS THE POCONOS IN TERMS OF ICING, THOUGH WE MIGHT BE A COUPLE HOURS TOO LONG ON THIS. OTHERWISE RAIN WILL CONTINUE TO OVERSPREAD FROM THE SOUTH-SOUTHWEST AS THE COASTAL WAVE CONTINUES ITS NORTHWARD PROGRESS PASSING JUST OFF THE DELMARVA COAST. A WEAK COLD FRONT WILL THEN PUSH IN FROM THE WEST AND EFFECTIVELY PUT AN END TO PRECIPITATION BUT IN DOING SO COLDER AIR BEGINS TO FILTER BACK INTO THE REGION. MODELS CONTINUE TO SHOW A DISCONTINUITY WITH EACH OTHER IN TERMS OF THE FINAL WAVE ON TUESDAY...DOES IT SKIRT BY TO OUR SOUTH OR HAVE ENOUGH LATITUDE TO BRUSH BY OVERHEAD. UPPER LEVEL SUPPORT IN TERMS OF THE RIGHT ENTRANCE TO THE STRONG JET AND WEAK Q-VEC CONVERGENCE COUPLED WITH WEAK FGEN IN THE 700-500MB LAYER, SHOULD ALLOW FOR SOME MORE MOISTURE TO BE SQUEEZED OUT ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA TUESDAY AFTERNOON. THERMAL PROFILES WILL BE CONDUCIVE FOR ALL SNOW TO FALL THOUGH THE ONE MAJOR QUESTION BECOMES HOW MUCH ENERGY IS STILL LEFT IN THE MID-LEVELS. BY TUESDAY THE MID-LEVEL ENERGY BECOMES VERY STRUNG OUT AND MAY HAVE GIVEN ALL IT CAN SO ONLY TIME WILL TELL IN THE AFTERMATH OF TONIGHTS SYSTEM TO SEE IF IF CAN RECOVER. SPEAKING OF SNOWFALL, NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION THOUGH SOME OF THE MODELS ARE TRYING TO SHOW A QUICK BURST TUESDAY AFTERNOON WITH DECENT DENDRITIC GROWTH POSSIBLE WITH UPWARDS OF AN INCH IN SPOTS...MOST SOUTH AND EAST OF PHILLY. WITH THE FINAL WAVE GONE, HIGH PRESSURE WORKS BACK IN ON WEDNESDAY AND TEMPERATURES PLUMMET TO WELL BELOW SEASONAL AVERAGES...THROUGH AT LEAST THE END OF THE WORK WEEK. A SLIGHT MODERATION IS EXPECTED BY SATURDAY AS THE FLOW BEGINS TO VEER SLIGHTLY TOWARDS THE WEST-SOUTHWEST. THE NEXT POTENTIAL SYSTEM LOOKS TO SKIRT BY THE COAST SATURDAY NIGHT INTO SUNDAY THROWING SOME MOISTURE BACK ACROSS THE REGION. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THIS AFTERNOON...A BAND OF HEAVY SNOW WILL IMPACT KILG TO KPHL AND KPNE ESPECIALLY FOR AWHILE. THIS WILL PRODUCE MVFR TO IFR CONDITIONS WITH SNOWFALL RATES AROUND AN INCH PER HOUR. THIS BAND SHOULD TRANSLATE TO THE NORTHEAST THROUGH THE AFTERNOON WITH PERHAPS SOME LESSENING OF THE SNOW INTENSITY POSSIBLE LATER. ELSEWHERE, SNOW IS EXPECTED TO ARRIVE NORTHWARD WITH THE ARRIVAL LAST AT KABE AND KTTN. THE SNOW MAY START TO MIX WITH SOME SLEET NEAR KPHL ON SOUTH AND EAST TOWARD EARLY EVENING. NORTH TO NORTHEAST WINDS 5-8 KNOTS. TONIGHT...A TRANSITION OF THE PRECIPITATION IS EXPECTED FROM SOUTHEAST TO NORTHWEST, WITH SNOW AND SLEET CHANGING TO FREEZING RAIN AND RAIN. KABE AND KRDG WILL HANG ONTO THE FROZEN/FREEZING PRECIPITATION THE LONGEST, WITH KMIV AND KACY HAVING ALL RAIN SOONER. MVFR AND TO EVEN IFR CONDITIONS /ESPECIALLY CEILINGS/ ARE EXPECTED. NORTHEAST WINDS GENERALLY AROUND 5 KNOTS, HOWEVER BECOMING EAST-SOUTHEAST MAINLY AT KACY OVERNIGHT. OUTLOOK... MONDAY...STILL EXPECTING AN MVFR/IFR DAY AS RAIN CONTINUES TO OVERSPREAD FROM THE SOUTH-SOUTHWEST. A COASTAL LOW PRESSURE WILL PASS BY HEADING TOWARDS NEW ENGLAND AND MAY HELP TO KEEP A PREDOMINANT EASTERLY FLOW ACROSS THE REGION THROUGH THE MORNING HOURS AND THEN AS THE LOW MOVES AWAY WE BACK TOWARDS THE WEST. RAIN SHOULD BEGIN TO COME TO AN END DURING THE EVENING HOURS. TUESDAY...ONE FINAL WAVE OF LOW PRESSURE MAY IMPACT THE REGION DURING THE DAY PROVIDING MVFR/IFR SNOW. NOT QUITE SURE HOW FAR INLAND THE PRECIPITATION WILL FALL BUT HIGHER CONFIDENCE AT THIS POINT IS FROM MIV AND ACY...MAYBE THE I-95 CORRIDOR. OTHERWISE WE WILL BE VFR. WEDNESDAY - THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND THROUGH TONIGHT. MEANWHILE, LOW PRESSURE WILL TRACK UP THE OHIO VALLEY WITH A SECONDARY WEAKER LOW DEVELOP NEAR THE MID ATLANTIC COAST. AS THIS OCCURS, THE NORTHEASTERLY WIND WILL INCREASE SOME AND THEN TURN EASTERLY TONIGHT ESPECIALLY ACROSS THE NORTHERN ZONES. BASED ON THE FORECAST SOUNDINGS FROM THE NAM/GFS AND ECMWF, WE OPTED TO ISSUE A SMALL CRAFT ADVISORY FOR OUR TWO NORTHERN ZONES STARTING THIS EVENING AND GOING THROUGH 11Z MONDAY AT THIS POINT. WE WILL REEVALUATE THIS LATER TODAY. WE ALSO EXTENDED THE ADVISORY FOR OUR CENTRAL AND SOUTHERN OCEAN ZONES UNTIL 05Z TONIGHT AFTER COLLABORATING WITH WFO AKQ. WE HELD OFF ON AN ADVISORY FOR DELAWARE BAY AS THE GREATER FLOW LOOKS TO BE ACROSS THE OCEAN. SEAS WILL BE NEAR 5 FEET THROUGH TONIGHT GIVEN THE FLOW INCREASING SOME AND TURNING MORE NORTHEAST AND EAST. OUTLOOK... MONDAY...LINGERING SMALL CRAFT ISSUES POSSIBLE AS THE COASTAL WAVE PULLS FURTHER NORTH WITH SEAS AND WINDS BEGINNING TO RELAX BY LATE IN THE DAY. TUESDAY AND WEDNESDAY...A FAIRLY TIGHT GRADIENT WILL EXIST FOR THE TUESDAY THROUGH WEDNESDAY TIME FRAME WITH WINDS PICKING UP OUT OF THE WEST OR NORTHWEST. WE COULD NEAR GALES ACROSS THE NORTH FOR A BRIEF TIME PERIOD WEDNESDAY MORNING BUT CONFIDENCE IS RATHER LOW RIGHT NOW. CONFIDENCE IS HIGH THAT A SMALL CRAFT WILL BE NEEDED FOR THAT TIME FRAME. THURSDAY...WINDS AND SEAS WILL SUBSIDE BELOW SMALL CRAFT ADVISORY LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR PAZ060>062. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR PAZ101- 103>106. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR PAZ054-055. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR PAZ070-071- 102. NJ...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR NJZ007-008. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR NJZ009. WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR NJZ021>023. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR NJZ001. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NJZ016>020- 027. WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NJZ010-012- 013-015. DE...WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR DEZ002- 003. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR DEZ001. MD...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR MDZ008. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ012- 015-019-020. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ452>455. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST MONDAY FOR ANZ450-451. && $$ SYNOPSIS...HEAVENER/MEOLA NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...HEAVENER AVIATION...GORSE/HEAVENER MARINE...GORSE/HEAVENER/MEOLA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1139 AM EST SUN DEC 8 2013 .SYNOPSIS... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND BY THIS EVENING. A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT LAKES REGION THROUGH TODAY AND MONDAY, DRAGGING A COLD FRONT THROUGH OUR AREA LATE MONDAY. MEANWHILE, A LOW PRESSURE SYSTEM WILL DEVELOP AND MOVE UP ALONG THE MIDDLE ATLANTIC COAST ON MONDAY. A SECONDARY FRONT WILL MOVE THROUGH THE REGION LATE TUESDAY INTO WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE REGION FROM THE WEST ON WEDNESDAY BEFORE SHIFTING EAST OF THE AREA AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN EXTENSIVE SURFACE AND UPPER AIR ANALYSIS THIS MORNING REVEALS RATHER ROBUST LOW-LEVEL WAA ACROSS PORTIONS OF THE MID ATLANTIC. TO THE NORTH OF THIS ZONE, THERE APPEARS TO BE A TIGHTENING AREA OF WEST TO EAST FRONTOGENETIC FORCING. THIS FORCING IS SEEN IN THE RADAR DATA AS A BANDED FEATURE ACROSS NORTHERN MARYLAND AND IT IS NOW MOVING ACROSS NORTHERN DELAWARE AND SOUTHWESTERN NEW JERSEY. THE LATEST HRRR HAS THIS FEATURE PLACED WELL SO FAR AND IT SLIDES IT NORTHEASTWARD ACROSS PHILADELPHIA AND THEN ACROSS PORTIONS OF SOUTHERN NEW JERSEY. THERE ARE REPORTS OF MODERATE TO HEAVY SNOW OCCURRING WITH THIS BANDED FEATURE, WHICH IS RESULTING IN MUCH MORE EFFICIENT ACCUMULATIONS. AS A RESULT, WE EXPANDED THE WINTER WEATHER ADVISORY TO THE EAST ANOTHER TIER OF ZONES. IT MAY NEED TO BE EXTENDED TO THE COAST, BUT EVENTUAL WARMING ALOFT AND FROM THE OCEAN INFLUENCE SHOULD KEEP SNOW ACCUMULATIONS LOWERED TOWARD THE COAST. THIS IS OF LOWER CONFIDENCE HOWEVER. WE ALSO ADDED IN LIGHT ICING INTO THE NEW ADVISORY PORTION AS SOUNDINGS DO SHOW A POTENTIAL WINDOW OF OPPORTUNITY THIS EVENING DURING THE TRANSITION PERIOD. THE GRIDS ARE BEING UPDATED TO INCREASE SNOW AMOUNTS SOME ESPECIALLY FOR THE AREA BEING AFFECTED BY THE BANDING FEATURE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... HOWEVER, AS WAA INCREASES THRU THE NIGHT, THE PRECIP WILL BEGIN TO MIX AND EVENTUALLY CHANGE TO ALL RAIN FROM SE TO NW. THE GFS IS THE WARMEST/FASTEST MDL WITH THIS TRANSITION. THE NAM/WRF AND ECMWF ARE A BIT SLOWER BUT STILL HAVE THE CHANGEOVER REACHING THE I-95 CORRIDOR SHORTLY AFTER MIDNIGHT. FURTHER AND W, THE WINTRY PRECIP WILL HANG ON LONGER. CURRENT THINKING IS THE GFS IS TOO WARM/TOO QUICK WITH THE TRANSITION. IT IS STILL PSBL THERE COULD BE A PD OF FZRA ALG THE I-95 CORRIDOR, BUT CONFIDENCE IS LOW ON THIS OCCURRENCE SO NO HEADLINES ARE BEING ISSUED FOR NOW. IF THE GFS IS CORRECT, THEY WILL LIKELY NOT BE NEEDED. IF MORE SLEET OCCURS IN THE TRANSITION, THEY MAY NOT BE NEEDED EITHER. BY MON MRNG, ALL BUT THE FAR N AND W SHOULD BE RAIN. TEMPS WILL RISE OVERNIGHT AS THE WAA KICKS IN. THIS IS DEFINITELY A TRICKY TEMP DAY (AND NIGHT) AND A COUPLE OF DEGREES MAKES A WORLD OF DIFFERENCE! && .LONG TERM /MONDAY THROUGH SATURDAY/... THINGS SHOULD BEGIN TO WIND DOWN BY MONDAY MORNING WITH JUST A FEW ISSUES LEFT LINGERING ACROSS THE POCONOS IN TERMS OF ICING, THOUGH WE MIGHT BE A COUPLE HOURS TOO LONG ON THIS. OTHERWISE RAIN WILL CONTINUE TO OVERSPREAD FROM THE SOUTH-SOUTHWEST AS THE COASTAL WAVE CONTINUES ITS NORTHWARD PROGRESS PASSING JUST OFF THE DELMARVA COAST. A WEAK COLD FRONT WILL THEN PUSH IN FROM THE WEST AND EFFECTIVELY PUT AN END TO PRECIPITATION BUT IN DOING SO COLDER AIR BEGINS TO FILTER BACK INTO THE REGION. MODELS CONTINUE TO SHOW A DISCONTINUITY WITH EACH OTHER IN TERMS OF THE FINAL WAVE ON TUESDAY...DOES IT SKIRT BY TO OUR SOUTH OR HAVE ENOUGH LATITUDE TO BRUSH BY OVERHEAD. UPPER LEVEL SUPPORT IN TERMS OF THE RIGHT ENTRANCE TO THE STRONG JET AND WEAK Q-VEC CONVERGENCE COUPLED WITH WEAK FGEN IN THE 700-500MB LAYER, SHOULD ALLOW FOR SOME MORE MOISTURE TO BE SQUEEZED OUT ACROSS AT LEAST THE SOUTHERN HALF OF THE CWA TUESDAY AFTERNOON. THERMAL PROFILES WILL BE CONDUCIVE FOR ALL SNOW TO FALL THOUGH THE ONE MAJOR QUESTION BECOMES HOW MUCH ENERGY IS STILL LEFT IN THE MID-LEVELS. BY TUESDAY THE MID-LEVEL ENERGY BECOMES VERY STRUNG OUT AND MAY HAVE GIVEN ALL IT CAN SO ONLY TIME WILL TELL IN THE AFTERMATH OF TONIGHTS SYSTEM TO SEE IF IF CAN RECOVER. SPEAKING OF SNOWFALL, NOT EXPECTING MUCH IN THE WAY OF ACCUMULATION THOUGH SOME OF THE MODELS ARE TRYING TO SHOW A QUICK BURST TUESDAY AFTERNOON WITH DECENT DENDRITIC GROWTH POSSIBLE WITH UPWARDS OF AN INCH IN SPOTS...MOST SOUTH AND EAST OF PHILLY. WITH THE FINAL WAVE GONE, HIGH PRESSURE WORKS BACK IN ON WEDNESDAY AND TEMPERATURES PLUMMET TO WELL BELOW SEASONAL AVERAGES...THROUGH AT LEAST THE END OF THE WORK WEEK. A SLIGHT MODERATION IS EXPECTED BY SATURDAY AS THE FLOW BEGINS TO VEER SLIGHTLY TOWARDS THE WEST-SOUTHWEST. THE NEXT POTENTIAL SYSTEM LOOKS TO SKIRT BY THE COAST SATURDAY NIGHT INTO SUNDAY THROWING SOME MOISTURE BACK ACROSS THE REGION. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REST OF TODAY...A BAND OF MODERATE TO HEAVY SNOW WILL IMPACT KILG TO KPHL ESPECIALLY FOR AWHILE. THIS WILL PRODUCE MVFR TO IFR CONDITIONS WITH SNOWFALL RATES NEARING AN INCH PER HOUR. THIS BAND SHOULD TRANSLATE TO THE NORTHEAST THROUGH THE AFTERNOON WITH PERHAPS SOME LESSENING OF THE SNOW INTENSITY POSSIBLE LATER. ELSEWHERE, SNOW IS EXPECTED TO ARRIVE NORTHWARD WITH THE ARRIVAL LAST AT KABE AND KTTN. THE SNOW MAY START TO MIX WITH SOME SLEET NEAR KPHL ON SOUTH AND EAST TOWARD EARLY EVENING. NORTH TO NORTHEAST WINDS 5-8 KNOTS. TONIGHT...A TRANSITION OF THE PRECIPITATION IS EXPECTED FROM SOUTHEAST TO NORTHWEST, WITH SNOW AND SLEET CHANGING TO FREEZING RAIN AND RAIN. KABE AND KRDG WILL HANG ONTO THE FROZEN/FREEZING PRECIPITATION THE LONGEST, WITH KMIV AND KACY HAVING ALL RAIN SOONER. MVFR AND TO EVEN IFR CONDITIONS /ESPECIALLY CEILINGS/ ARE EXPECTED. NORTHEAST WINDS GENERALLY AROUND 5 KNOTS, HOWEVER BECOMING EAST-SOUTHEAST MAINLY AT KACY OVERNIGHT. OUTLOOK... MONDAY...STILL EXPECTING AN MVFR/IFR DAY AS RAIN CONTINUES TO OVERSPREAD FROM THE SOUTH-SOUTHWEST. A COASTAL LOW PRESSURE WILL PASS BY HEADING TOWARDS NEW ENGLAND AND MAY HELP TO KEEP A PREDOMINANT EASTERLY FLOW ACROSS THE REGION THROUGH THE MORNING HOURS AND THEN AS THE LOW MOVES AWAY WE BACK TOWARDS THE WEST. RAIN SHOULD BEGIN TO COME TO AN END DURING THE EVENING HOURS. TUESDAY...ONE FINAL WAVE OF LOW PRESSURE MAY IMPACT THE REGION DURING THE DAY PROVIDING MVFR/IFR SNOW. NOT QUITE SURE HOW FAR INLAND THE PRECIPITATION WILL FALL BUT HIGHER CONFIDENCE AT THIS POINT IS FROM MIV AND ACY...MAYBE THE I-95 CORRIDOR. OTHERWISE WE WILL BE VFR. WEDNESDAY - THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND THROUGH TONIGHT. MEANWHILE, LOW PRESSURE WILL TRACK UP THE OHIO VALLEY WITH A SECONDARY WEAKER LOW DEVELOP NEAR THE MID ATLANTIC COAST. AS THIS OCCURS, THE NORTHEASTERLY WIND WILL INCREASE SOME AND THEN TURN EASTERLY TONIGHT ESPECIALLY ACROSS THE NORTHERN ZONES. BASED ON THE FORECAST SOUNDINGS FROM THE NAM/GFS AND ECMWF, WE OPTED TO ISSUE A SMALL CRAFT ADVISORY FOR OUR TWO NORTHERN ZONES STARTING THIS EVENING AND GOING THROUGH 11Z MONDAY AT THIS POINT. WE WILL REEVALUATE THIS LATER TODAY. WE ALSO EXTENDED THE ADVISORY FOR OUR CENTRAL AND SOUTHERN OCEAN ZONES UNTIL 05Z TONIGHT AFTER COLLABORATING WITH WFO AKQ. WE HELD OFF ON AN ADVISORY FOR DELAWARE BAY AS THE GREATER FLOW LOOKS TO BE ACROSS THE OCEAN. SEAS WILL BE NEAR 5 FEET THROUGH TONIGHT GIVEN THE FLOW INCREASING SOME AND TURNING MORE NORTHEAST AND EAST. OUTLOOK... MONDAY...LINGERING SMALL CRAFT ISSUES POSSIBLE AS THE COASTAL WAVE PULLS FURTHER NORTH WITH SEAS AND WINDS BEGINNING TO RELAX BY LATE IN THE DAY. TUESDAY AND WEDNESDAY...A FAIRLY TIGHT GRADIENT WILL EXIST FOR THE TUESDAY THROUGH WEDNESDAY TIME FRAME WITH WINDS PICKING UP OUT OF THE WEST OR NORTHWEST. WE COULD NEAR GALES ACROSS THE NORTH FOR A BRIEF TIME PERIOD WEDNESDAY MORNING BUT CONFIDENCE IS RATHER LOW RIGHT NOW. CONFIDENCE IS HIGH THAT A SMALL CRAFT WILL BE NEEDED FOR THAT TIME FRAME. THURSDAY...WINDS AND SEAS WILL SUBSIDE BELOW SMALL CRAFT ADVISORY LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR PAZ060>062. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR PAZ101>106. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR PAZ054-055. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ070- 071. NJ...WINTER WEATHER ADVISORY UNTIL 5 AM EST MONDAY FOR NJZ007-008. WINTER WEATHER ADVISORY UNTIL 3 AM EST MONDAY FOR NJZ009. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 7 AM EST MONDAY FOR NJZ001. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ016>019. WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NJZ010-012- 013-015. DE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DEZ001. MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ008- 012-015-019-020. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ452>455. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST MONDAY FOR ANZ450-451. && $$ SYNOPSIS...HEAVENER/MEOLA NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...HEAVENER AVIATION...GORSE/HEAVENER MARINE...GORSE/HEAVENER/MEOLA
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
817 PM EST MON DEC 9 2013 .UPDATE... HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC WATERS EXTENDING BACK WEST INTO SOUTH FLORIDA...AS A COLD FRONT SLOWLY DRIFTS SOUTH THROUGH NORTH FLORIDA. THIS WILL KEEP THE WEATHER DRY OVER SOUTH FLORIDA TONIGHT ALONG WITH LIGHT WINDS AND MOSTLY CLEAR SKIES OVER THE MAINLAND AREAS. SO FOG FORMATION IS EXPECTED OVERNIGHT TONIGHT OVER THE INTERIOR AND WEST COAST METRO AREAS...WITH EVEN AREAS OF FOG OVER THE INTERIOR SECTION TOWARDS SUNRISE. FOR THE MARINE SECTION OF SOUTH FLORIDA...THE WINDS WILL REMAIN FROM THE EASTERLY DIRECTION AT 10 TO 15 KNOTS TONIGHT. THIS WILL KEEP THE SEAS IN THE ATLANTIC WATERS AT 2 TO 4 FEET AND IN THE GULF WATERS AT 1 TO 3 FEET. SO ON CHANGES ARE EXPECTED IN THE MARINE PACKAGE FOR TONIGHT. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. && .AVIATION... VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE 24 HR TAF PERIOD WITH LIGHT SE WIND. A FEW SHOWERS DEVELOPING AND SPREADING ASHORE ALONG THE EAST COAST WILL REMAIN POSSIBLE. HOWEVER...CONFIDENCE IS TOO LOW AT THIS TIME TO INSERT VCSH WITH THIS PACKAGE. && .UPDATE...54/BNB AVIATION...85/AG .PREV DISCUSSION... /ISSUED 152 PM EST MON DEC 9 2013/ DISCUSSION... QUIET WEATHER WILL CONTINUE THROUGH TONIGHT, WITH WINDS BECOMING LIGHT AND VARIABLE TO CALM OVER THE INTERIOR AREAS. THERE COULD BE A ROUND OF FOG DEVELOPMENT. THE HRRR DOES KEEP IT OUT OF ITS FORECAST THROUGH 04Z, WHICH IS THE EXTENT OF THE RUN AT THIS TIME. HOWEVER, BUFKIT IS SHOWING THAT IT DOES FAVOR FOG. SO, HAVE KEPT PATCHY FOG IN THE FORECAST FROM 06Z THROUGH 12Z. PATTERN WISE, HIGH PRESSURE WILL WEAKEN THROUGH THE NIGHT. THIS IS AHEAD OF A COLD FRONT THAT IS CURRENTLY WELL TO THE WEST, OVER NEW ORLEANS. THIS FRONT WILL APPROACH THE FLORIDA PENINSULA AND WILL BE ENHANCED BY A 500 MB SHORT WAVE. HOWEVER, AS IT APPROACHES FLORIDA, THE ASSOCIATED LOW WILL BE QUICKLY MOVING OFF TO THE NORTHEAST, TAKING MOST OF THE ENERGY AND MOISTURE WITH IT. THIS WILL CAUSE THE FRONT TO STALL SOMEWHERE OVER NORTH CENTRAL FLORIDA WEDNESDAY NIGHT. AHEAD OF THIS FRONT, THERE WILL BE AN AREA OF CLOUDS AND SHOWERS THAT WILL BEGIN TO AFFECT THE SOUTHERN TIP OF FLORIDA TOMORROW MORNING. MODELS ARE IN DISAGREEMENT WITH THE EXTENT OF THE COVERAGE OF THE SHOWERS. THE GFS KEEPS MOST OF THE ACTIVITY TO THE SOUTH OF I75, BUT IT DOES HAVE SHOWERS OVER THE PENINSULA. THE ECMWF KEEPS ALL ACTIVITY OFFSHORE, EXCEPT PERHAPS A LIGHT COASTAL SHOWER. HAVE KEPT A CHANCE OF SHOWERS FOR MOST AREAS SOUTH OF I75 AND A SLIGHT CHANCE NORTH OF THAT FOR THE AFTERNOON HOURS. AFTER THAT, MOST OF THE ACTIVITY IS EITHER OVER THE COASTAL WATERS, OR JUST ALONG THE COAST, WITH INLAND AREAS FAIRLY DRY. BY WEDNESDAY AFTERNOON, THE FRONT LOOKS TO DRIFT FAR ENOUGH SOUTH TO BRING A CHANCE OF SHOWERS TO AREAS NORTH OF I75. AFTER THAT, A SECONDARY HIGH BUILDS OVER THE MISSISSIPPI VALLEY, WHICH WILL PUSH THE FRONT FURTHER SOUTH AND OVER THE FLORIDA STRAIGHTS. AS IT DOES, IT MAY ENHANCE SHOWER ACTIVITY THURSDAY AFTERNOON AND EVENING. THEN, EASTERLY FLOW RETURNS AS THE SURFACE HIGH SLIDES EASTWARD. ALSO, AN UPPER LEVEL RIDGE WILL BE BUILDING OVER THE AREA FOR THE WEEKEND. THIS WILL PROBABLY BRING MOSTLY DRY CONDITIONS FOR THE WEEKEND, WITH THE EXCEPTION OF A SLIGHT CHANCE OF SHOWERS BY SUNDAY. AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE AFTERNOON AND EVENING HOURS. A MODERATE SOUTHEASTERLY FLOW WILL PREVAIL ACROSS THE REGION TONIGHT INTO TUESDAY. IN INCREASE IN MOISTURE IS EXPECTED TUESDAY MORNING WITH A CHANCE OF SHOWERS POSSIBLE LATE TUESDAY AND NOT INCLUDED IN THIS TAF ISSUANCE. MARINE... HIGH PRESSURE WILL BEGIN TO WEAKEN TONIGHT. THIS WILL BRING WINDS AROUND TO THE SOUTH TOMORROW AS WELL AS SOME SHOWERS TO THE SOUTH FLORIDA COASTAL WATERS. A COLD FRONT WILL APPROACH THE AREA WEDNESDAY NIGHT AND STALL OVER CENTRAL FLORIDA AND ALL BUT DISSIPATE. HIGH PRESSURE WILL QUICKLY TO THE NORTH, BEHIND THE FRONT. THIS WILL BRING AN EASTERLY FLOW BACK TO THE SOUTH FLORIDA WATERS WEDNESDAY. WITH THE WEAK FRONTAL BOUNDARY IN THE AREA, IT WILL BRING A CHANCE OF SHOWERS FOR THE COASTAL WATERS THROUGH THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 69 82 70 82 / - 20 20 30 FORT LAUDERDALE 73 82 71 82 / - 40 30 30 MIAMI 72 82 72 83 / - 40 30 30 NAPLES 67 81 67 82 / - 20 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
8 PM EST MON DEC 9 2013 .DISCUSSION... CURRENT-OVERNIGHT... PREVIOUS ZONES DISCUSSION CURRENT-TONIGHT...THE LOW-LEVEL RIDGE AXIS IS FORECAST TO REMAIN ACROSS THE CENTRAL PENINSULA THROUGH TONIGHT...THOUGH LIGHT WINDS WILL VEER TO SOUTH/SOUTH-SOUTHWEST BY SUNRISE TUE MORNING. THE FRONTAL BOUNDARY THAT HAS BEEN HUNG UP NORTH AND WEST OF THE AREA WILL SETTLE INTO THE FLORIDA PANHANDLE LATE OVERNIGHT. WIND SPEEDS ABOVE THE SURFACE MAY BE TOO STRONG FOR ANY WIDESPREAD FOG DEVELOPMENT OVERNIGHT...THOUGH WILL RETAIN PATCHY FOG WORDING IN GRIDS/ZONES FOR AREAS NEAR AND NORTH OF THE I-4 CORRIDOR. WILL KEEP CONDITIONS DRY. OVERNIGHT LOWS CONTINUE MILD AND IN THE 60S. TUE...A RATHER STRONG UPPER JET WILL GIVE THE FRONT THE NECESSARY INCENTIVE TO PUSH SOUTHWARD FROM THE FLORIDA PANHANDLE INTO THE NORTH-CENTRAL PENINSULA DURING THE DAY. THE RIDGE AXIS WILL RETREAT SOUTH AND EASTWARD. WINDS WILL RESPOND BY VEERING TO SOUTHWEST DURING THE MORNING AND WEST-SOUTHWEST BY LATE IN THE DAY NEAR AND NORTH OF THE I-4 CORRIDOR. FURTHER SOUTHWARD WINDS LOOK TO REMAIN SOUTH OR SOUTH-SOUTHWEST. WE MAY SEE DEVELOPMENT OF THE EAST COAST SEA BREEZE IN THE AFTERNOON WHICH WOULD BACK WINDS ALONG THE TREASURE COAST TO EAST-SOUTHEAST. WIND SPEEDS WILL AVERAGE 7-12 MPH. DEEP LAYER MOISTURE WILL BE SLOW TO INCREASE AND THE AIRMASS WILL NEED TIME TO MODIFY. FOR THIS REASON WILL ONLY CARRY A 20 PERCENT CHANCE OF POPS IN THE AFTERNOON FOR NORTH OF THE I-4 CORRIDOR. POPS AROUND 10 PERCENT SOUTH OF HERE. ASIDE FROM THE JET ENERGY TO THE NORTH MID LEVEL DYNAMIC SUPPORT WILL REMAIN RATHER WEAK. FORECAST HIGHS IN THE LOWER TO MIDDLE 80S AHEAD OF THE APPROACHING FRONT. WED...(MODIFIED PREV DISC) LTST GUID SUGGEST THE APCHG FRONT WILL STALL OVER SO CENTRAL FL AND ACT AS A POOL FOR LOW LVL MOISTURE WHILE SUPPRESSING THE ATLC HIGH PRES RIDGE ACROSS SRN MOST FL. PRECIP CHANCES WILL BEST BE ASCD WITH THE STALLED BOUNDARY ROUGHLY ACROSS THE TREASURE COAST AND LOWER CHCS FOR POINTS NORTHWARD. THIS SETUP COULD FAVOR MEASURABLE RAIN FOR A COUPLE FORECAST PERIODS INVOF THE STALLED FEATURE...BUT POTENTIAL FOR ANY STRONG OR ORGANIZED CONVECTION WILL REMAIN LOW. DEEPENING ONSHORE FLOW WED WILL PUSH MAX TEMPS BACK TO WITHIN 5F DEG OF CLIMO AVG...STILL ABV AVG WITH READINGS IN THE M/U70S ALONG AND N OF I-4... U70S/L80S SPACE AND TREASURE COASTS. LIGHT N/NE FLOW WED NIGHT WILL KEEP MIN TEMPS IN THE L/M60S INTERIOR...M/U60S ALONG THE COAST. THU-FRI... PROGRESSIVE WX PATTERN THROUGH THE LATTER HALF OF THE WEEK AS THE JET PATTERN ACRS THE CONUS BECOMES LARGELY ZONAL IN NATURE. THE POST FRONTAL RIDGE OVER THE ERN CONUS ON WED WILL BE REINFORCED BY A POLAR RIDGE BY DAYBREAK THU. EMBEDDED WITHIN A STRONG ZONAL WIND COMPONENT...THIS NEW RIDGE WILL THEN PUSH OFF THE MID ATLC COAST BY WEEK`S END WHERE IT WILL GRADUALLY WEAKEN. THIS WILL ALLOW SFC/LOW LVL WINDS ACRS CENTRAL FL TO BACK TO THE N/NE AND FRESHEN ON THU...KEEPING SEASONABLE MAX/MIN TEMPS IN PLACE. LINGERING PRECIP INTO THU MRNG MNLY S OF THE I-4 CORRIDOR BEFORE THE COOLER AND MORE STABLE AIR WORKS ITS WAY INTO THE CWA. SAT-SUN... AS THE POLAR RIDGE BUILDS INTO THE W ATLC...WINDS WILL VEER TO THE S/SE ON SAT...THEN TO THE W/SW SAT NIGHT. THIS WILL ALLOW TEMPS TO WARM BACK ABV CLIMO AHEAD THRU MOST OF THE WEEKEND. GFS AND ECMWF INDICATING SIGNIFICANT DIFFERENCES WRT THE NEXT FRONTAL SYSTEM OVER THE WEEKEND: ECMWF HAS A MORE AMPLIFIED MID LVL SHORT WAVE OVER THE SRN PLAINS AND TAKES ITS PARENT LOW ACRS THE LWR MS VALLEY BY DAYBREAK SAT...WHILE GFS IS LESS AMPLIFIED IN THE MID LVLS AND CARRIES THE CORE OF ITS SYSTEM ACRS THE GREAT LAKES. NOT SURPRISINGLY...ECMWF EXTENDED MOS HAS A WETTER AND COOLER SOLUTION THAN GFS...POPS 15-20PCT POINTS HIGHER AND POST FRONTAL MAX TEMPS ARND 10F COOLER. WILL SPLIT THE DIFFERENCE FOR NOW AS THERE IS AMPLE TIME FOR SUBSEQUENT MODEL RUNS TO HAMMER OUT A BETTER CONSENSUS. && .AVIATION... OVERNIGHT...FORECAST SOUNDINGS ARE INDICATING THAT THE LOWEST LAYER(S) WILL DECOUPLE AFTER MIDNIGHT. THIS WILL ALLOW THE SURFACE WINDS AND WINDS JUST ABOVE THE SURFACE TO BECOME LIGHT...LESS THAN 5 MPH...OR CALM AND TO 15 KNOTS ABOVE THE INVERSION AFTER 08Z. THIS SETUP IS FAVORABLE FOR STRATUS AT OR BELOW FL010 RATHER THAN FOG. BEST LOCATIONS FOR FOG WILL BE FROM ORMOND BEACH TO DAYTONA BEACH TO LAKE KISSIMMEE AND WEST. ANY FOG THAT DOES FORM WILL BE MVFR VISIBILITY. VFR AFTER 10/14Z WITH ISOLATED LATE AFTERNOON SHOWERS POSSIBLE FROM DAYTONA TO KISSIMMEE NORTH AS A WEAK BOUNDARY APPROACHES NORTHERN AREAS DURING MAX DAYTIME HEATING AND INSTABILITY. PREVIOUS AVIATION DISCUSSION VFR CONDITIONS EXPECTED. DEEP SOUTHERLY FLOW MAY BE TOO STRONG FOR WIDESPREAD FOG FORMATION...BUT STILL EXPECT SOME PATCHY FOG NEAR AND NORTH OF THE I-4 CORRIDOR LATE OVERNIGHT INTO EARLY TUE MORNING. SOUTHEAST/SOUTH WINDS WILL FALL TO BELOW 5 KTS. A WEAK FRONTAL BOUNDARY TO THE NORTH SLIDES INTO NORTH-CENTRAL FL LATE IN THE DAY ON TUE WITH WINDS VEERING TO SW. A 20 PERCENT CHANCE OR LESS OF PRECIP WILL BE POSSIBLE TUE AFTERNOON AS THE AIRMASS SLOWLY MODIFIES. && .MARINE... CURRENT-OVERNIGHT...THE NOAA BUOYS WERE RECORDING SOUTH SOUTHEAST WINDS 10 TO 15 KNOTS AND 4 TO 5 FOOT SEAS...WITH A 3 FOOT LONG PERIOD EASTERLY SWELL..BETWEEN 20NM AND 42NM OFFSHORE. THE TWO NEARSHORE SCRIPPS BUOYS AT 4 AND 6NM OFF THE BEACHES WERE RECORDING 3 FOOT SEAS WITH A 2 FOOT LONG PERIOD SWELL. LATEST RUC13 RUN WAS INDICATING THAT THE WINDS SHIFT TO THE SOUTH AND SOUTH SOUTHWEST NORTH OF CAPE CANAVERAL AND INCREASE TO 15 KNOTS AWAY FROM THE COAST LATE OVERNIGHT. THERE MAY BE SOME 5 TO 6 FOOT SETS IN THE GULF STREAM FORT PIERCE INLET NORTH MAY PUT AN EXERCISE CAUTION FOR SEAS IN THE GULF STREAM BUT SEAS 5 FEET OR LESS OUTSIDE OF THE GULF STREAM OVERNIGHT. PREVIOUS MARINE DISCUSSION CURRENT-TONIGHT...THE LOW-LEVEL RIDGE AXIS REMAINS FIRM IN PLACE OVER THE CENTRAL PENINSULA OVERNIGHT. SSE/S WIND FLOW WILL VEER MORE SSW BY DAYBREAK TUE MORNING. SPEEDS WILL AVERAGE BETWEEN 10 AND 15 KTS OVER THE OPEN ATLANTIC. A LONG PERIOD SWELL WILL PUSH SEAS 3-4 FT VERY NEAR SHORE AND 4-5 FT FURTHER AWAY FROM THE COAST. WILL NOT RULE OUT AN ISOLATED SHOWER OVER THE GULF STREAM WATERS. TUE...THE RIDGE AXIS WEAKENS AS A COLD FRONTAL BOUNDARY PUSHES INTO THE NORTH-CENTRAL FL PENINSULA BY LATE IN THE DAY. WINDS WILL RESPOND BY VEERING SSW/SW DURING THE DAY. AN EAST COAST SEA BREEZE IS POSSIBLE ALONG THE TREASURE COAST IN THE AFTERNOON WHICH MAY BACK WINDS TO ESE. WIND SPEEDS BELOW 15 KTS AND ARE FORECAST TO FALL BELOW 10 KTS LATER IN THE AFTERNOON. SEAS 3-4 FT NEAR SHORE AND 4-5 FT OFFSHORE. WED-WED NIGHT...(PREVIOUS) GENTLE TO MODERATE N/NE BREEZE AS THE SFC RIDGE OVER THE MID ATLC BY A POLAR RIDGE THAT WILL PUSH OUT OF THE PAC NW THRU MIDWEEK. SEAS 3-4FT NEARSHORE AND 4-6FT OFFSHORE. THU-THU NIGHT...WINDS WILL FRESHEN OUT OF THE N AFT DAYBREAK TO 20-25KTS AND VEER TO THE THRU SUNSET NE THU NIGHT AS THE POLAR RIDGE MOVES ACRS THE APPALACHIAN AND APPROACHES THE MID ATLC COAST. SEAS BUILDING TO 5-7FT BY AFTN...6-8FT NEARSHORE AND 8-10FT OFFSHORE OVERNIGHT. FRI-FRI NIGHT...FRESH TO STRONG NE BREEZE WILL WEAKEN SLOWLY AS THE POLAR RIDGE PUSHES OFF THE MID ATLC COAST AND WEAKENS OVER THE W ATLC...BUT OVERALL CONDITIONS WILL REMAIN ROUGH. WINDS DECREASING TO ARND 20KTS THRU THE DAY...THEN TO 15-20KTS OVERNIGHT. SEAS 6-8FT NEARSHORE AND 8-10FT OFFSHORE THRU THE DAY...DECREASING TO 4-6FT NEARSHORE AND 6-8FT OFFSHORE OVERNIGHT. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECASTS...WIMMER IMPACT WX...KELLY
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
904 PM CST MON DEC 9 2013 .DISCUSSION... 718 PM CST ONLY ISSUES THUS FAR HAVE BEEN TEMPERATURES TAKING A NOSE DIVE. RFD DROPPED TO 3 DEGREES ALREADY WITH OTHER STATIONS UNDER CLEAR SKIES TANKING AS WELL. AS LOWERED LOW TEMPS FOR TONIGHT WITH OUTLYING AREAS DIPPING JUST BELOW ZERO. BASED ON TRENDS...TEMPS MAY FALL A BIT LOWER THAN CURRENTLY FORECAST FOR AREAS NORTH OF A LASALLE TO OHARE AIRPORT LINE. BASICALLY WHERE THE SKY IS CLEAR. USED HRRR TRENDS WITH A FEW HAND EDITS TO GET TEMP TREND TONIGHT SINCE AREAS UNDER THE CLOUD COVER WILL COOL VERY SLOWLY. ISSUED A SPS TO HIGHLIGHT THE COLD TEMPS AND WIND CHILLS SINCE THIS IS THE COLDEST WE HAVE BEEN THIS SEASON. MIN WIND CHILLS OF -10 TO -15 ARE EXPECTED FOR AREAS IN AND NORTH OF A LASALLE COUNTY TO WILL COUNTY LINE. ISOLATED AREAS NORTH OF I-90 MAY EVEN SEEN MIN WIND CHILLS APPROACHING -20. HOWEVER THE AREA OF -20 WILL NOT BE WIDESPREAD ENOUGH TO WARRANT A WIND CHILL ADVISORY. OTHERWISE MADE MINOR ADJUSTMENTS TO SKY COVER AS THE REST OF THE FORECAST IS ON TRACK. STILL EXPECTING TEMPS TO RISE A BIT AROUND SUNRISE AS CLOUD COVER ASSOCIATED WITH THE NEXT CLIPPER MOVE IN. JEE //PREV DISCUSSION... 253 PM CST IT APPEARS WE ARE STUCK IN MOTHER NATURES WINTER PATTERN...AND FOR THE NEXT SEVERAL DAYS IT DOES NOT APPEAR WE ARE LOOKING AT A BREAK FROM THIS SETUP. LONG-TERM PATTERN IS BEGINNING TO SHOW JUST A BRIEF RESPITE...THEN A RETURN TO UNSEASONABLY COLD SETUP. IT`S THE GIFT THAT KEEPS ON GIVING CLARK. THIS AFTERNOON/EVENING...WILL REMAIN RELATIVELY QUIET FOR THE FORECAST AREA...HOWEVER THAT WILL CHANGE TOWARDS DAYBREAK TUESDAY. SFC RIDGE HAS BECOME CENTERED ACROSS THE MID-MISSOURI VALLEY...BEGINNING TO STRETCH EAST THROUGH THE OHIO VALLEY. THE DEPARTING SFC LOW THAT BROUGHT THE FRESH BLANKET OF SNOW HAS LIFTED NORTHEAST OF LAKE HURON...MEANWHILE A CLIPPER IS BEGINNING TO DIP INTO THE NORTHERN PLAINS LATE THIS AFTERNOON. IR IMAGERY SHOWS A CHANNEL OF CLOUDS OVER SAINT LOUIS STRETCHING NORTHEAST THROUGH SOUTHERN LAKE MICHIGAN...ASSOCIATED WITH A FRONTAL BOUNDARY THAT CONTINUES TO SLOWLY SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA. TEMPS AHEAD OF THIS BOUNDARY HAVE HELD STEADY IN THE LOW 20S...WHILE BEHIND THIS BOUNDARY TEMPS HAVE ALREADY FALLEN INTO THE MID/UPR TEENS. ACROSS THE STATELINE INTO IOWA...TEMPS HAVE HELD IN THE SINGLE DIGITS ABOVE ZERO. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH WITH THE FIRST CLIPPER TONIGHT...AND AS A RESULT HAVE INCREASED POPS ACROSS THE NORTHERN CWFA. THE PRESSURE GRADIENT DOES INCREASE THIS EVENING...AND WILL PERSIST THRU DAYBREAK TUE. THIS WILL LIKELY RESULT IN SOME BLOWING SNOW. AS NOTED ABOUT INCREASED POPS...THIS HAS RESULTED IN LIGHT SNOW EXPECTED JUST BEFORE DAYBREAK TUE FOR THE NORTHERN HALF OF THE CWFA. USING THE COBB TECHNIQUE WOULD SUGGEST A FEW POINTS BETWEEN 09-12Z COULD PICK-UP A COUPLE TENTHS OF AN INCH OF SNOWFALL. WITH THE BREEZY CONDS EXPECTED...AND COLD AIR IN PLACE...TEMPS WILL LIKELY TUMBLE TO THE SINGLE DIGITS ABOVE ZERO AND WIND CHILL VALUES WELL BELOW ZERO AND NEARING -15 IN A FEW LOCATIONS WEST OF THE FOX VALLEY. CONFIDENCE...HIGH. TUESDAY THROUGH WEDNESDAY... 500MB TROUGH AXIS HAS TRENDED STRONGER...WHICH HAS ALSO DISPLACED THE CLIPPER POISED TO ARRIVE ACROSS THE REGION FURTHER SOUTH TUE MORNING. AS A RESULT HAVE INTRODUCED POPS TO ACCOMMODATE THIS THRU 18Z TUE. BUT IN TRADITIONAL FASHION...THIS CLIPPER SHUD QUICKLY PUSH EAST BY EARLY AFTN WITH WEAK SFC RIDGING PUSHING BACK INTO THE FORECAST AREA. SOME WEAK WARMING MAY OCCUR WITH THIS SYSTEM EARLY...ALLOWING TEMPS TO WARM INTO THE TEENS TO PSBLY LOW 20S ALONG THE SOUTHERN CWFA TUE AFTN. THEN YET ANOTHER CLIPPER IS PROGGED TO TRAVERSE THE REGION LATE TUE NGT/WED...WHICH HAS CONTINUED TO TREND FURTHER SOUTH AND STRONGER. WITH THE SFC RIDGE DRIFTING SOUTH INTO THE TENN VALLEY...THIS WILL LIKELY ALLOW THE WAVE TO PUSH ACROSS THE HEART OF THE CWFA. QPF OF ARND 0.10" FOR THIS SECOND CLIPPER SNOW RATIOS WILL HOVER ARND 15:1 TO 20:1. THE BEST OMEGA/LIFT IS PUSHING INTO THE FAVORED DGZ WED MORNING...WHICH COULD HELP PRODUCE LARGER DENDRITES AND INCREASE SNOWFALL ACCUM RATES. AT THIS POINT HAVE ACCUMS GENERALLY BETWEEN 1-3"...AND COULD SEE A FEW LOCATIONS BETWEEN THE I-80 AND I-88 CORRIDOR COULD PICK UP CLOSE TO 4" BY LATE WED MORNING. THEN HIGH PRESSURE BUILDS BACK INTO THE REGION WED NGT...SETTING THE STAGE FOR A VERY COLD NIGHT INTO THUR MORNING. THE RIDGE CENTER HAS ALSO TRENDED SLIGHTLY FURTHER SOUTH...WHICH WILL LIKELY KEEP SOME WEST/NORTHWEST WIND COMPONENT. DESPITE THIS TEMPS SHUD STILL RADIATE INTO THE SINGLE DIGITS BELOW ZERO. CONFIDENCE...HIGH. CONFIDENCE IN ACCUMULATING SNOWFALL WED...HIGH. THURSDAY THROUGH SUNDAY... PREVIOUS GUIDANCE HAD HELD THE SFC RIDGE OVER THE FORECAST AREA THUR MORNING...WITH DRY WEATHER. HOWEVER AS HAS BEEN THE CASE WITH THE PRIOR COUPLE OF CLIPPERS...AND PLACEMENT OF THE 500MB TROUGH AXIS...GUIDANCE HAS NOW INTRODUCED YET ANOTHER CLIPPER SLICING SOUTHEAST ACROSS THE NORTHERN PLAINS EARLY THUR...AND COULD BRING A PERIOD OF LIGHT SNOW/FLURRIES INTO NORTHERN IL THUR MORNING. THIS MAY RESULT IN TEMPS THUR MORNING NOT GETTING AS COLD...BUT THAT WILL HINGE UPON TIMING AND CLOUD COVER FROM THE AFOREMENTIONED CLIPPER. THEN A RELATIVELY QUIET PERIOD FOR FRI WITH THE 500MB FLOW TRYING TO FLATTEN...BUT THIS WILL ONLY BE BRIEF. GUIDANCE IS NOW BEGINNING TO TREND TOWARDS AN INVERTED TROUGH DEVELOPING IN THE WAKE OF THE SFC RIDGE FRI...WITH A STRONG SHORTWAVE TAKING SHAPE ACROSS THE SOUTHERN PLAINS FRIDAY EVENING. THIS SYSTEM WILL NEED TO BE CLOSELY MONITORED FOR THE UPCOMING WEEKEND...AS THIS COULD SPREAD ACCUMULATING SNOWFALL THROUGH THE OHIO VALLEY INTO NORTHERN IL/NORTHWEST IN. THE LATEST GFS INDICATES AN 850MB LOW ASSOCIATED WITH THIS INVERTED TROUGH...LIFTING NORTHEAST ACROSS CENTRAL IL THEN NORTHEAST INTO NORTHCENTRAL IN MIDDAY SAT. LLVL FLOW AHEAD OF THIS FEATURE WILL BE TURNING NORTHEAST SAT...SETTING UP THE POTENTIAL FOR A HYBRID SYSTEM OF LAKE EFFECT SNOW AND POTENTIALLY SYNOPTIC SNOW SAT. TEMPS SHUD BEGIN TO WARM TO NEAR 30 DEG...OR POSSIBLY THE FREEZING POINT FRI THRU SAT. THEN WITH YET ANOTHER ARCTIC AIRMASS POISED TO PUSH BEHIND THIS SYSTEM SUN. CONFIDENCE...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * LOW CHANCE FOR SNOW SHOWERS MID/LATE TUESDAY MORNING WITH BRIEF IFR VSBY POSSIBLE BUT COVERAGE MAY BE LOW. * SOUTHWEST WIND GUSTS 25-30 KT BY MID MORNING TURNING WEST AND INCREASING TO 30-35 KT EARLY AFTERNOON. * ACCUMULATING SNOW CHANCES INCREASE TUESDAY NIGHT...IFR LIKELY. MDB //DISCUSSION...UPDATED 00Z... STRONG WEST WINDS ARE BEGINNING TO EASE WITH GUST FREQUENCY DIMINISHING AS WELL. VFR WILL CONTINUE THROUGH THE NIGHT WITH WINDS TURNING SOUTHWEST LATE TONIGHT. WIND SPEEDS WILL INCREASE BY MID TUESDAY MORNING WITH GUSTS OF 25-30 KT DEVELOPING AS AN ALBERTA CLIPPER REACHES THE AREA. THE BULK OF THE SNOW WITH THIS SYSTEM WILL BE TO THE NORTH BUT EXPECT THAT THERE WILL BE AT LEAST A CHANCE FOR SOME SNOW SHOWERS TO EXTEND TOWARD THE TERMINALS DURING THE MORNING. COVERAGE MAY NOT BE ALL THAT HIGH AND CONFIDENCE IN OCCURRENCE IS SOMEWHAT LIMITED BUT WILL CONTINUE WITH VCSH/PROB30 MENTION FOR NOW. SHOULD HAVE BETTER CONFIDENCE GOING INTO THE OVERNIGHT AS THE SYSTEM TRACKS ACROSS THE DAKOTAS AND MINNESOTA/IOWA. SHOULD SNOW SHOWERS CROSS THE AREA THEN INTENSITY COULD BE SUCH THAT IFR VSBY COULD OCCUR FOR A SHORT TIME. THE SYSTEM WILL QUICKLY EXIT BY EARLY AFTERNOON TURNING WINDS WESTERLY AND ALLOWING WIND GUSTS TO INCREASE TO 30-35 KT BEFORE DIMINISHING TUESDAY EVENING. ATTENTION WILL THEN TURN TO A STRONGER CLIPPER SYSTEM WHICH WILL CROSS THE AREA TUESDAY NIGHT AND WEDNESDAY MORNING BRINGING MUCH BETTER CHANCES FOR ACCUMULATING SNOW AND IFR CONDITIONS. MDB //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM CONFIDENCE THAT THERE WILL BE SOME SNOW SHOWERS IN THE AREA MID/LATE TUESDAY MORNING. LOW-MEDIUM CONFIDENCE THAT IF SNOW SHOWERS DO OCCUR THEN BRIEF IFR VSBY IS POSSIBLE. * HIGH CONFIDENCE IN WIND FORECAST TUESDAY. * HIGH CONFIDENCE IN SNOW CHANCES INCREASING TUESDAY NIGHT AND MEDIUM CONFIDENCE IN AT LEAST SOME IFR. MDB //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...SNOW ENDING TOWARD MIDDAY. BECOMING VFR. THURSDAY...VFR. FRIDAY...VFR WITH SNOW CHANCES INCREASING FRIDAY EVENING. IFR DEVELOPING FRIDAY EVENING. SATURDAY...CHANCE FOR SNOW. IFR/MVFR. SUNDAY...IMPROVING TO VFR. MDB && .MARINE... 145 PM CST MAIN MARINE FORECAST CONCERNS ARE A COUPLE OF PERIODS OF GALE FORCE WINDS OVER NORTHERN LAKE MICHIGAN THIS AFTERNOON/EVENING...AND AGAIN TUESDAY AND TUESDAY NIGHT ACROSS THE ENTIRE LAKE. HAVE UPGRADED GALE WATCH TO A GALE WARNING FOR TUESDAY AND TUESDAY NIGHT. STRENGTHENING LOW PRESSURE WAS LOCATED JUST NORTH AND NORTHEAST OF LAKE SUPERIOR THIS AFTERNOON...AND WILL CONTINUE TO DEEPEN AS IT LIFTS TOWARD JAMES BAY THIS EVENING. AS THE LOW DEEPENS...A PERIOD OF TIGHTENING SURFACE PRESSURE GRADIENT WAS RESULTING IN LOW-END WEST GALES ACROSS MAINLY NORTHERN LAKE MICHIGAN WITH GRAND TRAVERSE LIGHT GUSTING 34 KTS AS OF NOON CST. GALES WILL LINGER TONIGHT AS THE LOW PULLS AWAY...GRADUALLY EASING AFTER MIDNIGHT ACROSS THE FAR NORTHERN PORTION OF THE LAKE AS WEAK HIGH PRESSURE RIDGING MOVES ACROSS THE WESTERN LAKES. THE LULL LOOKS TO BE BRIEF HOWEVER...AS A FAST MOVING CLIPPER SYSTEM CURRENTLY MOVING ACROSS FAR SOUTHERN SASKATCHEWAN TRAVELS QUICKLY TO THE UPPER MISSISSIPPI VALLEY OVERNIGHT...AND ACROSS THE NORTHERN/WESTERN GREAT LAKES REGION ON TUESDAY. THIS WILL INDUCE A QUICK RE-TIGHTENING OF THE SURFACE PRESSURE GRADIENT ACROSS LAKE MICHIGAN TUESDAY MORNING...WITH STRONG SURFACE-BASED MIXING AND COLD ADVECTION EXPECTED TO PRODUCE WESTERLY 40 KT GALES BASED ON MODEL FORECAST SOUNDINGS. GALES LOOK TO PERSIST INTO TUESDAY EVENING ACROSS THE SOUTH HALF OF THE LAKE...AND PAST MIDNIGHT FARTHER NORTH. HIGH PRESSURE THEN BUILDS SOUTHEAST FROM THE CENTRAL PLAINS THROUGH THE MID/LOWER MISSOURI AND LOWER OHIO RIVER VALLEYS WEDNESDAY AND WEDNESDAY NIGHT...ALLOWING GALES TO EASE THOUGH WINDS REMAIN WESTERLY IN THE 20-30 KT RANGE IN THE TIGHTER GRADIENT NORTH OF THE SURFACE HIGH AND SOUTH OF LOW PRESSURE WHICH LINGERS OVER HUDSON BAY. WEST WINDS WILL LINGER THROUGH THURSDAY AS THE HIGH SPREADS EAST THROUGH THE OHIO VALLEY...AND ANOTHER WEAK LOW CROSSES THE NORTHERN LAKES. IN THE NEAR TERM...SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS THROUGH EARLY TUESDAY... WITH WINDS/WAVES DIMINISHING MORE QUICKLY ALONG THE ILLINOIS SHORE TONIGHT. THE GALE WARNING TUESDAY/TUESDAY EVENING INCLUDES THE NEAR SHORE WATERS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3 AM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 8 AM TUESDAY. GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 AM TUESDAY TO 9 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
718 PM CST MON DEC 9 2013 .DISCUSSION... 718 PM CST ONLY ISSUES THUS FAR HAVE BEEN TEMPERATURES TAKING A NOSE DIVE. RFD DROPPED TO 3 DEGREES ALREADY WITH OTHER STATIONS UNDER CLEAR SKIES TANKING AS WELL. AS LOWERED LOW TEMPS FOR TONIGHT WITH OUTLYING AREAS DIPPING JUST BELOW ZERO. BASED ON TRENDS...TEMPS MAY FALL A BIT LOWER THAN CURRENTLY FORECAST FOR AREAS NORTH OF A LASALLE TO OHARE AIRPORT LINE. BASICALLY WHERE THE SKY IS CLEAR. USED HRRR TRENDS WITH A FEW HAND EDITS TO GET TEMP TREND TONIGHT SINCE AREAS UNDER THE CLOUD COVER WILL COOL VERY SLOWLY. ISSUED A SPS TO HIGHLIGHT THE COLD TEMPS AND WIND CHILLS SINCE THIS IS THE COLDEST WE HAVE BEEN THIS SEASON. MIN WIND CHILLS OF -10 TO -15 ARE EXPECTED FOR AREAS IN AND NORTH OF A LASALLE COUNTY TO WILL COUNTY LINE. ISOLATED AREAS NORTH OF I-90 MAY EVEN SEEN MIN WIND CHILLS APPROACHING -20. HOWEVER THE AREA OF -20 WILL NOT BE WIDESPREAD ENOUGH TO WARRANT A WIND CHILL ADVISORY. OTHERWISE MADE MINOR ADJUSTMENTS TO SKY COVER AS THE REST OF THE FORECAST IS ON TRACK. STILL EXPECTING TEMPS TO RISE A BIT AROUND SUNRISE AS CLOUD COVER ASSOCIATED WITH THE NEXT CLIPPER MOVE IN. JEE && .PREV DISCUSSION... 253 PM CST IT APPEARS WE ARE STUCK IN MOTHER NATURES WINTER PATTERN...AND FOR THE NEXT SEVERAL DAYS IT DOES NOT APPEAR WE ARE LOOKING AT A BREAK FROM THIS SETUP. LONG-TERM PATTERN IS BEGINNING TO SHOW JUST A BRIEF RESPITE...THEN A RETURN TO UNSEASONABLY COLD SETUP. IT`S THE GIFT THAT KEEPS ON GIVING CLARK. THIS AFTERNOON/EVENING...WILL REMAIN RELATIVELY QUIET FOR THE FORECAST AREA...HOWEVER THAT WILL CHANGE TOWARDS DAYBREAK TUESDAY. SFC RIDGE HAS BECOME CENTERED ACROSS THE MID-MISSOURI VALLEY...BEGINNING TO STRETCH EAST THROUGH THE OHIO VALLEY. THE DEPARTING SFC LOW THAT BROUGHT THE FRESH BLANKET OF SNOW HAS LIFTED NORTHEAST OF LAKE HURON...MEANWHILE A CLIPPER IS BEGINNING TO DIP INTO THE NORTHERN PLAINS LATE THIS AFTERNOON. IR IMAGERY SHOWS A CHANNEL OF CLOUDS OVER SAINT LOUIS STRETCHING NORTHEAST THROUGH SOUTHERN LAKE MICHIGAN...ASSOCIATED WITH A FRONTAL BOUNDARY THAT CONTINUES TO SLOWLY SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA. TEMPS AHEAD OF THIS BOUNDARY HAVE HELD STEADY IN THE LOW 20S...WHILE BEHIND THIS BOUNDARY TEMPS HAVE ALREADY FALLEN INTO THE MID/UPR TEENS. ACROSS THE STATELINE INTO IOWA...TEMPS HAVE HELD IN THE SINGLE DIGITS ABOVE ZERO. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH WITH THE FIRST CLIPPER TONIGHT...AND AS A RESULT HAVE INCREASED POPS ACROSS THE NORTHERN CWFA. THE PRESSURE GRADIENT DOES INCREASE THIS EVENING...AND WILL PERSIST THRU DAYBREAK TUE. THIS WILL LIKELY RESULT IN SOME BLOWING SNOW. AS NOTED ABOUT INCREASED POPS...THIS HAS RESULTED IN LIGHT SNOW EXPECTED JUST BEFORE DAYBREAK TUE FOR THE NORTHERN HALF OF THE CWFA. USING THE COBB TECHNIQUE WOULD SUGGEST A FEW POINTS BETWEEN 09-12Z COULD PICK-UP A COUPLE TENTHS OF AN INCH OF SNOWFALL. WITH THE BREEZY CONDS EXPECTED...AND COLD AIR IN PLACE...TEMPS WILL LIKELY TUMBLE TO THE SINGLE DIGITS ABOVE ZERO AND WIND CHILL VALUES WELL BELOW ZERO AND NEARING -15 IN A FEW LOCATIONS WEST OF THE FOX VALLEY. CONFIDENCE...HIGH. TUESDAY THROUGH WEDNESDAY... 500MB TROUGH AXIS HAS TRENDED STRONGER...WHICH HAS ALSO DISPLACED THE CLIPPER POISED TO ARRIVE ACROSS THE REGION FURTHER SOUTH TUE MORNING. AS A RESULT HAVE INTRODUCED POPS TO ACCOMMODATE THIS THRU 18Z TUE. BUT IN TRADITIONAL FASHION...THIS CLIPPER SHUD QUICKLY PUSH EAST BY EARLY AFTN WITH WEAK SFC RIDGING PUSHING BACK INTO THE FORECAST AREA. SOME WEAK WARMING MAY OCCUR WITH THIS SYSTEM EARLY...ALLOWING TEMPS TO WARM INTO THE TEENS TO PSBLY LOW 20S ALONG THE SOUTHERN CWFA TUE AFTN. THEN YET ANOTHER CLIPPER IS PROGGED TO TRAVERSE THE REGION LATE TUE NGT/WED...WHICH HAS CONTINUED TO TREND FURTHER SOUTH AND STRONGER. WITH THE SFC RIDGE DRIFTING SOUTH INTO THE TENN VALLEY...THIS WILL LIKELY ALLOW THE WAVE TO PUSH ACROSS THE HEART OF THE CWFA. QPF OF ARND 0.10" FOR THIS SECOND CLIPPER SNOW RATIOS WILL HOVER ARND 15:1 TO 20:1. THE BEST OMEGA/LIFT IS PUSHING INTO THE FAVORED DGZ WED MORNING...WHICH COULD HELP PRODUCE LARGER DENDRITES AND INCREASE SNOWFALL ACCUM RATES. AT THIS POINT HAVE ACCUMS GENERALLY BETWEEN 1-3"...AND COULD SEE A FEW LOCATIONS BETWEEN THE I-80 AND I-88 CORRIDOR COULD PICK UP CLOSE TO 4" BY LATE WED MORNING. THEN HIGH PRESSURE BUILDS BACK INTO THE REGION WED NGT...SETTING THE STAGE FOR A VERY COLD NIGHT INTO THUR MORNING. THE RIDGE CENTER HAS ALSO TRENDED SLIGHTLY FURTHER SOUTH...WHICH WILL LIKELY KEEP SOME WEST/NORTHWEST WIND COMPONENT. DESPITE THIS TEMPS SHUD STILL RADIATE INTO THE SINGLE DIGITS BELOW ZERO. CONFIDENCE...HIGH. CONFIDENCE IN ACCUMULATING SNOWFALL WED...HIGH. THURSDAY THROUGH SUNDAY... PREVIOUS GUIDANCE HAD HELD THE SFC RIDGE OVER THE FORECAST AREA THUR MORNING...WITH DRY WEATHER. HOWEVER AS HAS BEEN THE CASE WITH THE PRIOR COUPLE OF CLIPPERS...AND PLACEMENT OF THE 500MB TROUGH AXIS...GUIDANCE HAS NOW INTRODUCED YET ANOTHER CLIPPER SLICING SOUTHEAST ACROSS THE NORTHERN PLAINS EARLY THUR...AND COULD BRING A PERIOD OF LIGHT SNOW/FLURRIES INTO NORTHERN IL THUR MORNING. THIS MAY RESULT IN TEMPS THUR MORNING NOT GETTING AS COLD...BUT THAT WILL HINGE UPON TIMING AND CLOUD COVER FROM THE AFOREMENTIONED CLIPPER. THEN A RELATIVELY QUIET PERIOD FOR FRI WITH THE 500MB FLOW TRYING TO FLATTEN...BUT THIS WILL ONLY BE BRIEF. GUIDANCE IS NOW BEGINNING TO TREND TOWARDS AN INVERTED TROUGH DEVELOPING IN THE WAKE OF THE SFC RIDGE FRI...WITH A STRONG SHORTWAVE TAKING SHAPE ACROSS THE SOUTHERN PLAINS FRIDAY EVENING. THIS SYSTEM WILL NEED TO BE CLOSELY MONITORED FOR THE UPCOMING WEEKEND...AS THIS COULD SPREAD ACCUMULATING SNOWFALL THROUGH THE OHIO VALLEY INTO NORTHERN IL/NORTHWEST IN. THE LATEST GFS INDICATES AN 850MB LOW ASSOCIATED WITH THIS INVERTED TROUGH...LIFTING NORTHEAST ACROSS CENTRAL IL THEN NORTHEAST INTO NORTHCENTRAL IN MIDDAY SAT. LLVL FLOW AHEAD OF THIS FEATURE WILL BE TURNING NORTHEAST SAT...SETTING UP THE POTENTIAL FOR A HYBRID SYSTEM OF LAKE EFFECT SNOW AND POTENTIALLY SYNOPTIC SNOW SAT. TEMPS SHUD BEGIN TO WARM TO NEAR 30 DEG...OR POSSIBLY THE FREEZING POINT FRI THRU SAT. THEN WITH YET ANOTHER ARCTIC AIRMASS POISED TO PUSH BEHIND THIS SYSTEM SUN. CONFIDENCE...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * WESTERLY WIND GUSTS TO 25 KT DIMINISHING NEXT 1-2 HRS. * CHANCE FOR SNOW SHOWERS MID/LATE TUESDAY MORNING WITH BRIEF IFR VSBY POSSIBLE BUT COVERAGE MAY BE LOW. * SOUTHWEST WIND GUSTS 25-30 KT BY MID MORNING TURNING WEST AND INCREASING TO 30-35 KT EARLY AFTERNOON. * ACCUMULATING SNOW CHANCES INCREASE TUESDAY NIGHT...IFR LIKELY. MDB //DISCUSSION...UPDATED 00Z... STRONG WEST WINDS ARE BEGINNING TO EASE WITH GUST FREQUENCY DIMINISHING AS WELL. VFR WILL CONTINUE THROUGH THE NIGHT WITH WINDS TURNING SOUTHWEST LATE TONIGHT. WIND SPEEDS WILL INCREASE BY MID TUESDAY MORNING WITH GUSTS OF 25-30 KT DEVELOPING AS AN ALBERTA CLIPPER REACHES THE AREA. THE BULK OF THE SNOW WITH THIS SYSTEM WILL BE TO THE NORTH BUT EXPECT THAT THERE WILL BE AT LEAST A CHANCE FOR SOME SNOW SHOWERS TO EXTEND TOWARD THE TERMINALS DURING THE MORNING. COVERAGE MAY NOT BE ALL THAT HIGH AND CONFIDENCE IN OCCURRENCE IS SOMEWHAT LIMITED BUT WILL CONTINUE WITH VCSH/PROB30 MENTION FOR NOW. SHOULD HAVE BETTER CONFIDENCE GOING INTO THE OVERNIGHT AS THE SYSTEM TRACKS ACROSS THE DAKOTAS AND MINNESOTA/IOWA. SHOULD SNOW SHOWERS CROSS THE AREA THEN INTENSITY COULD BE SUCH THAT IFR VSBY COULD OCCUR FOR A SHORT TIME. THE SYSTEM WILL QUICKLY EXIT BY EARLY AFTERNOON TURNING WINDS WESTERLY AND ALLOWING WIND GUSTS TO INCREASE TO 30-35 KT BEFORE DIMINISHING TUESDAY EVENING. ATTENTION WILL THEN TURN TO A STRONGER CLIPPER SYSTEM WHICH WILL CROSS THE AREA TUESDAY NIGHT AND WEDNESDAY MORNING BRINGING MUCH BETTER CHANCES FOR ACCUMULATING SNOW AND IFR CONDITIONS. MDB //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE IN WIND GUSTS DIMINISHING NEXT FEW HOURS. * MEDIUM CONFIDENCE THAT THERE WILL BE SOME SNOW SHOWERS IN THE AREA MID/LATE TUESDAY MORNING. LOW-MEDIUM CONFIDENCE THAT IF SNOW SHOWERS DO OCCUR THEN BRIEF IFR VSBY IS POSSIBLE. * HIGH CONFIDENCE IN WIND FORECAST TUESDAY. * HIGH CONFIDENCE IN SNOW CHANCES INCREASING TUESDAY NIGHT AND MEDIUM CONFIDENCE IN AT LEAST SOME IFR. MDB //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...SNOW ENDING TOWARD MIDDAY. BECOMING VFR. THURSDAY...VFR. FRIDAY...VFR WITH SNOW CHANCES INCREASING FRIDAY EVENING. IFR DEVELOPING FRIDAY EVENING. SATURDAY...CHANCE FOR SNOW. IFR/MVFR. SUNDAY...IMPROVING TO VFR. MDB && .MARINE... 145 PM CST MAIN MARINE FORECAST CONCERNS ARE A COUPLE OF PERIODS OF GALE FORCE WINDS OVER NORTHERN LAKE MICHIGAN THIS AFTERNOON/EVENING...AND AGAIN TUESDAY AND TUESDAY NIGHT ACROSS THE ENTIRE LAKE. HAVE UPGRADED GALE WATCH TO A GALE WARNING FOR TUESDAY AND TUESDAY NIGHT. STRENGTHENING LOW PRESSURE WAS LOCATED JUST NORTH AND NORTHEAST OF LAKE SUPERIOR THIS AFTERNOON...AND WILL CONTINUE TO DEEPEN AS IT LIFTS TOWARD JAMES BAY THIS EVENING. AS THE LOW DEEPENS...A PERIOD OF TIGHTENING SURFACE PRESSURE GRADIENT WAS RESULTING IN LOW-END WEST GALES ACROSS MAINLY NORTHERN LAKE MICHIGAN WITH GRAND TRAVERSE LIGHT GUSTING 34 KTS AS OF NOON CST. GALES WILL LINGER TONIGHT AS THE LOW PULLS AWAY...GRADUALLY EASING AFTER MIDNIGHT ACROSS THE FAR NORTHERN PORTION OF THE LAKE AS WEAK HIGH PRESSURE RIDGING MOVES ACROSS THE WESTERN LAKES. THE LULL LOOKS TO BE BRIEF HOWEVER...AS A FAST MOVING CLIPPER SYSTEM CURRENTLY MOVING ACROSS FAR SOUTHERN SASKATCHEWAN TRAVELS QUICKLY TO THE UPPER MISSISSIPPI VALLEY OVERNIGHT...AND ACROSS THE NORTHERN/WESTERN GREAT LAKES REGION ON TUESDAY. THIS WILL INDUCE A QUICK RE-TIGHTENING OF THE SURFACE PRESSURE GRADIENT ACROSS LAKE MICHIGAN TUESDAY MORNING...WITH STRONG SURFACE-BASED MIXING AND COLD ADVECTION EXPECTED TO PRODUCE WESTERLY 40 KT GALES BASED ON MODEL FORECAST SOUNDINGS. GALES LOOK TO PERSIST INTO TUESDAY EVENING ACROSS THE SOUTH HALF OF THE LAKE...AND PAST MIDNIGHT FARTHER NORTH. HIGH PRESSURE THEN BUILDS SOUTHEAST FROM THE CENTRAL PLAINS THROUGH THE MID/LOWER MISSOURI AND LOWER OHIO RIVER VALLEYS WEDNESDAY AND WEDNESDAY NIGHT...ALLOWING GALES TO EASE THOUGH WINDS REMAIN WESTERLY IN THE 20-30 KT RANGE IN THE TIGHTER GRADIENT NORTH OF THE SURFACE HIGH AND SOUTH OF LOW PRESSURE WHICH LINGERS OVER HUDSON BAY. WEST WINDS WILL LINGER THROUGH THURSDAY AS THE HIGH SPREADS EAST THROUGH THE OHIO VALLEY...AND ANOTHER WEAK LOW CROSSES THE NORTHERN LAKES. IN THE NEAR TERM...SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS THROUGH EARLY TUESDAY... WITH WINDS/WAVES DIMINISHING MORE QUICKLY ALONG THE ILLINOIS SHORE TONIGHT. THE GALE WARNING TUESDAY/TUESDAY EVENING INCLUDES THE NEAR SHORE WATERS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3 AM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 8 AM TUESDAY. GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 AM TUESDAY TO 9 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 10 PM MONDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
957 PM EST MON DEC 9 2013 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 148 PM EST MON DEC 9 2013 SEVERAL WEAK WEATHER SYSTEMS AFFECT OUR REGION TODAY INTO MIDWEEK WITH MORE SIGNIFICANT SYSTEM FOR THIS WEEKEND. COLD ARCTIC HIGH PRESSURE TO RULE IN BETWEEN WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH EARLY NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 957 PM EST MON DEC 9 2013 FOR THE LATEST UPDATE...TIMING LOOKS PRETTY GOOD AS ECHOES ARE STRENGTHENING OVER SOUTHERN ILLINOIS AND OBSERVATIONS OF LIGHT SNOW ARE BEGINNING TO COME IN FROM THERE. RAP AND HRRR CONTINUE TO SHOW GOOD DEVELOPMENT OVER THE SOUTHWEST BY AROUND 5-6Z. DID DROP SNOWFALL AMOUNTS PRIOR TO 6Z WITH SNOW JUST GETTING GOING THEN. INCREASED VALUES IN THE 6-12Z TIME BASED ON SHORT TERM MODEL OUTPUT. ALSO NOTED IN THE SHORT TERM GUIDANCE WAS A SLIGHT SHIFT SOUTH IN THE MEASURABLE PRECIPITATION...BUT WITH THE SHARP GRADIENT ALREADY IN THE POP GRIDS DID NOT THINK A CHANGE THERE WAS NEEDED. IN SNOW AMOUNTS THOUGH KEPT SIMILAR VALUES AROUND 1.5 INCHES IN THE SOUTH BUT DROPPED THEM IN THE NORTH SO THE TERRE HAUTE TO SOUTH INDY TO RUSHVILLE AREAS SHOULD ONLY SEE A TENTH UP TO A FEW TENTHS OF AN INCH. CONTINUED WITH EARLIER SPS TO HIGHLIGHT SNOWFALL AND SLICK CONDITIONS EXPECTED FOR TUESDAY MORNING COMMUTE. PREVIOUS DISCUSSION FOLLOWS... CONCERN FOR TONIGHT IS SNOW/NO SNOW BOUNDARY AND HOW MUCH SNOW WILL OCCUR. WILL NOT ISSUE ADVISORY FOR THIS BUT MAKE MENTION IN HAZARDOUS WEATHER OUTLOOK AND SPECIAL WEATHER STATEMENT. AS TAIL END OF FIRST WEAK SHORT WAVE EXITS GREAT LAKES THIS AFTERNOON THE SECOND ONE OVER THE TX PANHANDLE REGION BEGINS TO TAKE SHAPE AND AIM ON THE OHIO VALLEY. MODELS IN GOOD AGREEMENT ON RAPID SPREAD OF NARROW SNOW BAND ENE ACROSS SOUTHERN AND CENTRAL INDIANA SOUTH OF I-70 LATE EVENING AND OVERNIGHT...QUICKLY EXITING BEFORE SUNRISE. THOUGH MOISTURE IS SOMEWHAT LIMITED...BRIEF PERIOD OF DENDRITIC GROWTH MAXES OUT OVER SOUTHERN COUNTIES AND WITH RATIOS NEAR 15 TO ONE...EXPECT SNOW AMOUNTS OVER ONE INCH BY DAWN FROM VINCENNES TO BEDFORD-BLOOMINGTON...COLUMBUS AND SEYMOUR. LOCAL TWO INCH AMOUNTS WILL LIKELY OCCUR. THE CUT-OFF FOR NO SNOW WILL BE NEARLY PARALLEL AND JUST A BIT NORTH OF I-70 SO SOUTH SIDE OF INDY METRO COULD SEE HALF INCH WHILE NORTH SIDE GETS JUST A DUSTING. CURRENT FORECAST TEMPS NOT BAD BUT WITH BRIEF PERIOD OF PARTIAL CLEARING THIS EVENING...ESPECIALLY NORTHERN COUNTIES...HAVE ADJUSTED TEMPS DOWN A COUPLE DEGREES BUT STILL 10-18F RANGE NW TO SE. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... ISSUED AT 148 PM EST MON DEC 9 2013 TONIGHT/S SYSTEM WILL BE RAPIDLY EXITING TUESDAY MORNING WITH GUSTY WEST WINDS AND CLEARING SKIES DEVELOPING IN THE MORNING. CURRENT MAX TEMPS IN LINE WITH LATEST DATA AND DESPITE SUNSHINE EXPECT NO BETTER THAN MID TO UPPER 20S. TUESDAY NIGHT...SKIES BEGIN TO CLOUD OVER ACROSS NORTHERN COUNTIES AS CLIPPER SYSTEM AND ARCTIC FRONT SWEEPS INTO WESTERN GREAT LAKES BY DAYBREAK WEDNESDAY. SOUTHERN COUNTIES REMAIN UNDER THE INFLUENCE OF COLD HIGH PRESSURE AND MAINTAIN MOSTLY CLEAR SKIES. EXPECTING SIMILAR LOWS WITH READINGS IN 10 TO 15F RANGE. WEDNESDAY...CURRENTLY LOOKS LIKE THE QUICK CLIPPER SYSTEM/S MEASURABLE SNOWS WOULD REMAIN NORTH OF A LAFAYETTE TO MUNCIE LINE AND EVEN THERE AMOUNTS SHOULD BE NO MORE THAN A DUSTING TO HALF INCH. STRONG ARCTIC HIGH PRESSURE RAPIDLY CLEARS SKIES WEDNESDAY AFTERNOON AND SETS STAGE FOR CLEAR SKY WEDNESDAY NIGHT WITH SINGLE DIGIT LOWS AFTER SLOWLY FALLING TEMPS WEDNESDAY AFTERNOON. HIGH PRESSURE SETTLING INTO THE TENNESSEE VALLEY THURSDAY BRINGS RETURN FLOW TO SOUTHWEST BUT LITTLE MODERATION OF TEMPS UNDER SUNNY SKIES. FORECAST MAX TEMPS UPPER TEENS TO LOWER 20S STILL APPEAR LIKELY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... ISSUED AT 255 PM EST MON DEC 9 2013 MAIN CHALLENGE FOR THE EXTENDED IS THE ARRIVAL AND IMPACT OF ANOTHER POTENTIALLY MESSY WINTRY SYSTEM INTO THE OHIO VALLEY FRIDAY NIGHT AND SATURDAY. UPPER FLOW PATTERN WILL BRIEFLY TRANSITION FROM THE DEEP TROUGH TO MORE OF A BROAD SOUTHWEST FLOW. AN UPPER WAVE WILL EJECT OUT OF NORTHERN MEXICO ON FRIDAY AND QUICKLY TRACK INTO THE OHIO VALLEY BY SATURDAY. A WEAK SURFACE WAVE WILL DEVELOP OVER THE SOUTHERN ROCKIES AND MOVE INTO THE TENNESSEE VALLEY ON SATURDAY. THE MODEL DIFFERENCES DEVELOP WITH RESPECT TO THE TIMING OF THE UPPER WAVE AND THE STRENGTH OF THE SURFACE LOW. OP GFS CONTINUES TO HOLD THE UPPER WAVE FURTHER WEST AND BRINGS A STRONGER SURFACE WAVE INTO THE REGION SATURDAY...WHILE THE GLOBAL MODELS ARE MORE PROGRESSIVE ALOFT WITH A WEAKER SURFACE WAVE TRACKING FURTHER TO THE SOUTH. THE TRACK AND INTENSITY OF THE SURFACE WAVE WILL DETERMINE HOW MUCH WARM AIR WITHIN THE BOUNDARY LAYER CAN BE ADVECTED NORTH INTO THE REGION LATE FRIDAY NIGHT AND SATURDAY. AT THIS POINT...AM LEANING TOWARDS THE COOLER GLOBAL MODELS WHICH LIMIT ANY POTENTIAL MIXING OF PRECIP TO FAR SOUTHERN COUNTIES WHERE CRITICAL LOW LEVEL THICKNESSES RISE TO AROUND 1305M FOR ABOUT 6-12 HOURS. SHOULD THIS COME TO PASS...SOUNDINGS WOULD SUPPORT FREEZING RAIN AS THE PREDOMINANT TYPE LATE FRIDAY NIGHT INTO SATURDAY FOR SEVERAL HOURS. WITH STILL PLENTY OF UNCERTAINTY AT THIS EARLY STAGE...WILL CARRY A RA/SN MIX OVER THE FAR SOUTH WITH SNOW OVER THE REST OF THE AREA. ENOUGH MOISTURE ACCOMPANYING THIS SYSTEM THAT COULD SEE A FEW INCHES OF ACCUM FRIDAY NIGHT/SATURDAY IF PRECIP REMAINS LARGELY IN THE FORM OF SNOW. WILL CERTAINLY BE KEEPING A CLOSE EYE ON THE EVOLUTION OF THIS SYSTEM IN THE DAYS TO COME. BEHIND THE SATURDAY STORM...COLDER AIR WILL ONCE AGAIN RETURN AS THE POLAR VORTEX PINWHEELS THROUGH THE NORTHERN GREAT LAKES. HIGHS IN THE 30S FRIDAY AND SATURDAY WILL FALL BACK INTO THE LOWER 20S BY MONDAY WITH SINGLE DIGIT LOWS RETURNING EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR THE 100300Z KIND TAF UPDATE/... ISSUED AT 916 PM EST MON DEC 9 2013 NO SIGNIFICANT CHANGES MADE TO THE FORECAST AT THIS TIME. PREVIOUS DISCUSSION FOLLOWS. WEATHER DISTURBANCE CURRENTLY OVER THE SOUTHERN PLAINS IS EXPECTED TO TRACK RAPIDLY NORTHEAST...BRINGING A NARROW SWATH OF IFR...POSSIBLY BRIEF LIFR...VISIBILITY RESTRICTIONS IN SNOW BEGINNING AFTER ABOUT 100600Z. SHORT TERM MODELS SUGGEST KBMG WILL SEE THE BEST CHANCES FOR THESE CONDITIONS...WITH A LESSER THREAT AT KHUF/KIND. A SHIFT NORTH IN THE TRACK WILL RESULT IN IFR VISIBILITIES AT KHUF/KIND AS WELL...BUT THIS SEEMS A LESS LIKELY OUTCOME AT THIS POINT. THE THREAT FOR SNOW IS EXPECTED TO END AT THE TAF SITES BY 101200Z. CEILINGS GENERALLY EXPECTED AT OR ABOVE 050 TONIGHT EXCEPT IN HEAVIER SNOW AREAS. NO WIND ISSUES EXPECTED AT THE TAF SITES THROUGH 101200Z. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TUCEK NEAR TERM...TUCEK/CP SHORT TERM...TUCEK LONG TERM....RYAN AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
939 PM EST MON DEC 9 2013 .UPDATE... ISSUED AT 930 PM EST MON DEC 9 2013 GRIDS HAVE BEEN UPDATED THROUGH THE EVENING FOR HOURLY OBSERVATION TRENDS. THIS LED TO NO SUBSTANTIAL CHANGES FROM THE PREVIOUS FORECAST SO FAR. LOOKING AT THE RECENT HRRR RUNS AND THE 18Z AND 0Z NAM DATA IT LOOKS LIKE AS THE PRECIPITATION ARRIVES...ISENTROPIC LIFT WILL BE ENHANCED NEAR THE VA BORDER...SO OPTED TO INCREASE POPS NORTHEAST ALONG THE VA BORDER SLIGHTLY FASTER THAN THE PREVIOUS FORECAST. THE 0Z NAM QPF IS GREATER THAN THE 18Z NAM RUN AND HAS TRENDED UPWARD TOWARD THE 12Z AND 18Z GFS QPF SOLUTIONS. QPF HAS BEEN TRENDED UPWARD IN THE GRIDS TO ACCOUNT FOR THIS AS WELL AS SNOW AMOUNTS IN SOME LOCATIONS. ALONG OR TO THE SOUTH OF A LINE FROM WILLIAMSBURG TO HYDEN TO PRESTONSBURG TO INEZ...THE QPF IN THE 0Z NAM AND 12Z AND 18Z GFS POINT TOWARD ENOUGH QPF TO POSSIBLY GET 4 INCHES OR MORE OF SNOW IF PRECIPITATION WERE TO ALL FALL AS SNOW. AS YOU MOVE FAR ENOUGH SOUTHEAST OF THAT LINE...THERE SHOULD BE ENOUGH OF A WARM NOSE AT THE ONSET FOR SOME SLEET TO CUT BACK ON POTENTIAL SNOW AMOUNTS AND THIS AREA WILL HAVE WARMER GROUND INITIALLY. THAT SAME AREA EXPERIENCED WARMER TEMPS ON MONDAY AFTERNOON THAN THE REST OF THE REGION. THESE FACTORS SHOULD KEEP THE SNOWFALL IN CHECK IN THIS MORE SOUTHEASTERN REGION...BUT THIS IS SOMETHING WE WILL CONTINUE TO MONITOR. AS IT STANDS NOW...IT APPEARS THAT THE HIGHER AMOUNTS SHOULD OCCUR ABOVE 2000 FEET AND NEAR A WILLIAMSBURG TO BARBOURVILLE TO HYDEN TO PRESTONSBURG TO INEZ LINE. THIS SCENARIO WOULD AFFECT PARTS OF INTERSTATE 75...THE HAL ROGERS PARKWAY AND KY HIGHWAY 80 CORRIDOR AS WELL AS PORTIONS OF US 23. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 435 PM EST MON DEC 9 2013 20Z SFC ANALYSIS SHOWS THE ARCTIC BOUNDARY HOLDING ON JUST TO OUR SOUTHEAST AWAITING THE NEXT WAVE OF PCPN TO MOVE UP ALONG IT FROM THE SOUTH. LOW CLOUDS ARE FOUND THROUGH MOST OF EAST KENTUCKY WITH JUST SOME SMALL BREAKS RIGHT ALONG THE SPINE OF THE APPALACHIANS. UNDER THESE AND CLOSER TO THE FRONT...TEMPERATURES ARE SIGNIFICANTLY MILDER THAN THE REST OF THE AREA. AS A RESULT...READINGS RANGE FROM THE MID AND UPPER 40S NEAR VIRGINIA TO THE LOW 30S NORTH OF INTERSTATE 64. DEWPOINTS...MEANWHILE...ARE IN THE UPPER 20S NORTHWEST TO LOWER 40S IN THE FAR SOUTHEAST. THE MODELS REMAIN IN SOME FLUX...STILL AT THIS LATE HOUR...REGARDING THE TANDEM MID LEVEL WAVES THAT WILL CROSS THE OHIO VALLEY ON TUESDAY. THE SOUTHERN ONE WILL HAVE THE MOST IMPACT ON THE AREA LATER TONIGHT BUT MAY NOT COMPLETELY PHASE WITH THE CLIPPER COMING IN FROM THE NORTH. BECAUSE OF THIS...THE RESULTING WEATHER HAS BEEN SHIFTING IN THE MODEL SOLUTIONS WITH EACH RUN. REGARDLESS...THE COMBINED TROUGH WILL SWEEP THROUGH THE OHIO VALLEY AND CENTRAL APPALACHIANS BY 00Z WEDNESDAY WITH FAST...FLAT FLOW TO FOLLOW. A GENERAL MODEL BLEND WAS USED FOR THE FORECAST WITH THE 12Z NAM AND GFS TAKING THE LEAD... ALTHOUGH THE HRRR WAS ALSO INCLUDED FOR THE PCPN ONSET AND TYPE EARLY. SENSIBLE WEATHER WILL FEATURE A QUICK HIT OF PCPN AS THE LAST SFC WAVE MOVES NORTHEAST ALONG THE TIGHTENING ARCTIC BOUNDARY JUST TO OUR SOUTHEAST. EXPECT THE PCPN TO MOVE BACK IN AROUND MIDNIGHT STARTING ALONG THE TENNESSEE BORDER IN THE FAR SOUTHWEST AND QUICKLY SPREADING NORTHEAST WITH TIME. THE LATEST MODELS ARE TARGETING THE SOUTHEAST 2/3RDS OF THE CWA FOR A QUARTER INCH OR SO OF QPF AND LIGHTER AMOUNTS TAPERING QUICKLY TO THE NORTHWEST. THE NORTHERN PORTION OF THIS HYBRID CLIPPER/WAVE WILL LIKELY HAVE HIGHER SNOW RATIOS TO COMPENSATE FOR THE LESSER QPF THERE. ACROSS THE FAR SOUTHEAST...THERE WILL BE A BETTER CHANCE OF SLEET MIXING IN WITH THE SNOW AT THE ONSET SO HAVE CUT THE SNOW AMOUNTS IN THIS AREA. THE SNOW WILL LIKELY COME DOWN QUICK FOR SEVERAL HOURS ACROSS THE AREA RIGHT BEFORE THE MORNING-SCHOOL COMMUTE. ACCORDINGLY...WE HAVE HOISTED A WSW FROM MIDNIGHT THROUGH THE MORNING ACROSS THE AREA...LINGERING THE ADVISORY IN THE FAR SOUTHEAST THROUGH MID AFTERNOON TUESDAY. THE SNOW PULLS AWAY QUICKLY AND DRIER AIR BEHIND THE FINALLY DEPARTING ARCTIC BOUNDARY WILL CLEAR THE SKY AND POPS SETTING THE STAGE FOR A VERY COLD NIGHT INTO WEDNESDAY MORNING. USED THE CONSSHORT TO BASE THE TEMPS AND TD ON THROUGH 18Z TUESDAY... CONSALL THEREAFTER...WHILE ALLOWING THE DIURNAL FROM THE NAM12 TO GUIDE THE HOURLY TEMPS THROUGH THE SHORT TERM...TOO. BCCONSSHORT WAS USED AS A STARTING POINT FOR WINDS THROUGH 18Z AND THE BCCONSALL AFTER THAT. AS FOR POPS...ENDED UP CLOSEST TO THE SLIGHTLY HIGHER MET NUMBERS ACROSS THE AREA TONIGHT INTO TUESDAY AND BASICALLY KEPT THINGS DRY ON TUESDAY NIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 257 PM EST MON DEC 9 2013 MODELS ARE IN REASONABLE AGREEMENT THROUGH THE WEEK AND INTO THE UPCOMING WEEKEND WITH ONLY SOME SMALL DIFFERENCES. CONFIDENCE IS INCREASING AROUND THE UPCOMING STORM FOR FRIDAY NIGHT AND SATURDAY. HIGH PRESSURE WILL FINALLY MAKE A RETURN FOR WEDNESDAY WITH A FULL DAY OF SUNSHINE. A FAST MOVING VORT MAX WILL TEMPORARILY SUPPRESS THE HIGH TO THE SOUTH AS IT PUSHES A COLD FRONT ACROSS EASTERN KENTUCKY. MOISTURE REMAINS VERY LIMITED WITH THIS FEATURE AND AT BEST A PERIOD OF FLURRIES COULD OCCUR. HIGH PRESSURE WILL REBUILD OVER THE AREA FROM THURSDAY INTO FRIDAY. A SHARP MID LEVEL TROUGH WILL EJECT OUT OF THE SOUTHWEST FRIDAY NIGHT INTO SATURDAY...WITH A SURFACE LOW TRACKING ACROSS THE REGION. RIGHT NOW IT LOOKS LIKE THE TRACK SHOULD TAKE IT RIGHT OVER SOUTHEAST KENTUCKY WITH THE WARM SECTOR SURGING INTO THE AREA LATE FRIDAY NIGHT. WHILE A PERIOD OF SNOW/SLEET MAY BE POSSIBLE AT THE ONSET...ESPECIALLY ACROSS THE NORTH...WE SHOULD SEE A QUICK TRANSITION OVER TO ALL RAIN. RAIN WILL CONTINUE INTO SATURDAY. AS THE SYSTEM DEPARTS...COLD AIR WILL WRAP BACK INTO EASTERN KENTUCKY WITH PRECIPITATION CHANGING OVER TO SNOW SATURDAY NIGHT. AT THIS TIME...MOISTURE AND LIFT APPEARS TO BE FAIRLY LIMITED WITH UPSLOPE FLOW...SO ANY ACCUMULATIONS WILL LIKELY BE SMALL AND MAYBE CONFINED TO JUST THE HIGHER ELEVATIONS. DRIER...BUT COLDER WEATHER WILL THEN BE SEEN INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 815 PM EST MON DEC 9 2013 CONFIDENCE IN THE DETAILS OF SNOW DEVELOPING ACROSS THE AREA OVERNIGHT HAS INCREASED WITH BETTER MODEL AGREEMENT...AND ALL SNOW IS ANTICIPATED AT THE TAF SITES. ACCORDINGLY...HAVE CONTINUED WITH A PERIOD OF LOW CIGS...AND VIS AT THE TAF SITES STARTING BETWEEN 6Z TO 9Z THROUGH ABOUT 13Z TO 16Z. MVFR CIGS ARE EXPECTED DURING THE FIRST 6 HOURS OF THE PERIOD...WITH IFR DURING THE PERIOD OF SNOW FALLING AND POSSIBLE AT LEAST BRIEF DROPS BELOW AIRPORT MINS DURING THE HEAVIEST SNOW. WINDS WILL BE WEST TO NORTHWEST THROUGH THE PERIOD AT 5 TO 10 KTS...BUT DURING ANY HEAVIER BOUTS OF SNOW THERE MAY BE A BRIEF PICK UP WITH GUSTS TO 15 KTS OR SO. CIGS SHOULD IMPROVE BACK TO MVFR BETWEEN 13Z AND 17Z AND THEN TO VFR LATE IN THE PERIOD AT ALL THE TAF SITES. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON EST TUESDAY FOR KYZ044- 050>052. WINTER WEATHER ADVISORY UNTIL 2 PM EST TUESDAY FOR KYZ058>060- 068-069-079-080-083-084-104-106>109-111-112-114. WINTER WEATHER ADVISORY UNTIL 4 PM EST TUESDAY FOR KYZ085>088- 110-113-115>120. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...KAS AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
828 PM EST MON DEC 9 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 435 PM EST MON DEC 9 2013 20Z SFC ANALYSIS SHOWS THE ARCTIC BOUNDARY HOLDING ON JUST TO OUR SOUTHEAST AWAITING THE NEXT WAVE OF PCPN TO MOVE UP ALONG IT FROM THE SOUTH. LOW CLOUDS ARE FOUND THROUGH MOST OF EAST KENTUCKY WITH JUST SOME SMALL BREAKS RIGHT ALONG THE SPINE OF THE APPALACHIANS. UNDER THESE AND CLOSER TO THE FRONT...TEMPERATURES ARE SIGNIFICANTLY MILDER THAN THE REST OF THE AREA. AS A RESULT...READINGS RANGE FROM THE MID AND UPPER 40S NEAR VIRGINIA TO THE LOW 30S NORTH OF INTERSTATE 64. DEWPOINTS...MEANWHILE...ARE IN THE UPPER 20S NORTHWEST TO LOWER 40S IN THE FAR SOUTHEAST. THE MODELS REMAIN IN SOME FLUX...STILL AT THIS LATE HOUR...REGARDING THE TANDEM MID LEVEL WAVES THAT WILL CROSS THE OHIO VALLEY ON TUESDAY. THE SOUTHERN ONE WILL HAVE THE MOST IMPACT ON THE AREA LATER TONIGHT BUT MAY NOT COMPLETELY PHASE WITH THE CLIPPER COMING IN FROM THE NORTH. BECAUSE OF THIS...THE RESULTING WEATHER HAS BEEN SHIFTING IN THE MODEL SOLUTIONS WITH EACH RUN. REGARDLESS...THE COMBINED TROUGH WILL SWEEP THROUGH THE OHIO VALLEY AND CENTRAL APPALACHIANS BY 00Z WEDNESDAY WITH FAST...FLAT FLOW TO FOLLOW. A GENERAL MODEL BLEND WAS USED FOR THE FORECAST WITH THE 12Z NAM AND GFS TAKING THE LEAD... ALTHOUGH THE HRRR WAS ALSO INCLUDED FOR THE PCPN ONSET AND TYPE EARLY. SENSIBLE WEATHER WILL FEATURE A QUICK HIT OF PCPN AS THE LAST SFC WAVE MOVES NORTHEAST ALONG THE TIGHTENING ARCTIC BOUNDARY JUST TO OUR SOUTHEAST. EXPECT THE PCPN TO MOVE BACK IN AROUND MIDNIGHT STARTING ALONG THE TENNESSEE BORDER IN THE FAR SOUTHWEST AND QUICKLY SPREADING NORTHEAST WITH TIME. THE LATEST MODELS ARE TARGETING THE SOUTHEAST 2/3RDS OF THE CWA FOR A QUARTER INCH OR SO OF QPF AND LIGHTER AMOUNTS TAPERING QUICKLY TO THE NORTHWEST. THE NORTHERN PORTION OF THIS HYBRID CLIPPER/WAVE WILL LIKELY HAVE HIGHER SNOW RATIOS TO COMPENSATE FOR THE LESSER QPF THERE. ACROSS THE FAR SOUTHEAST...THERE WILL BE A BETTER CHANCE OF SLEET MIXING IN WITH THE SNOW AT THE ONSET SO HAVE CUT THE SNOW AMOUNTS IN THIS AREA. THE SNOW WILL LIKELY COME DOWN QUICK FOR SEVERAL HOURS ACROSS THE AREA RIGHT BEFORE THE MORNING-SCHOOL COMMUTE. ACCORDINGLY...WE HAVE HOISTED A WSW FROM MIDNIGHT THROUGH THE MORNING ACROSS THE AREA...LINGERING THE ADVISORY IN THE FAR SOUTHEAST THROUGH MID AFTERNOON TUESDAY. THE SNOW PULLS AWAY QUICKLY AND DRIER AIR BEHIND THE FINALLY DEPARTING ARCTIC BOUNDARY WILL CLEAR THE SKY AND POPS SETTING THE STAGE FOR A VERY COLD NIGHT INTO WEDNESDAY MORNING. USED THE CONSSHORT TO BASE THE TEMPS AND TD ON THROUGH 18Z TUESDAY... CONSALL THEREAFTER...WHILE ALLOWING THE DIURNAL FROM THE NAM12 TO GUIDE THE HOURLY TEMPS THROUGH THE SHORT TERM...TOO. BCCONSSHORT WAS USED AS A STARTING POINT FOR WINDS THROUGH 18Z AND THE BCCONSALL AFTER THAT. AS FOR POPS...ENDED UP CLOSEST TO THE SLIGHTLY HIGHER MET NUMBERS ACROSS THE AREA TONIGHT INTO TUESDAY AND BASICALLY KEPT THINGS DRY ON TUESDAY NIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 257 PM EST MON DEC 9 2013 MODELS ARE IN REASONABLE AGREEMENT THROUGH THE WEEK AND INTO THE UPCOMING WEEKEND WITH ONLY SOME SMALL DIFFERENCES. CONFIDENCE IS INCREASING AROUND THE UPCOMING STORM FOR FRIDAY NIGHT AND SATURDAY. HIGH PRESSURE WILL FINALLY MAKE A RETURN FOR WEDNESDAY WITH A FULL DAY OF SUNSHINE. A FAST MOVING VORT MAX WILL TEMPORARILY SUPPRESS THE HIGH TO THE SOUTH AS IT PUSHES A COLD FRONT ACROSS EASTERN KENTUCKY. MOISTURE REMAINS VERY LIMITED WITH THIS FEATURE AND AT BEST A PERIOD OF FLURRIES COULD OCCUR. HIGH PRESSURE WILL REBUILD OVER THE AREA FROM THURSDAY INTO FRIDAY. A SHARP MID LEVEL TROUGH WILL EJECT OUT OF THE SOUTHWEST FRIDAY NIGHT INTO SATURDAY...WITH A SURFACE LOW TRACKING ACROSS THE REGION. RIGHT NOW IT LOOKS LIKE THE TRACK SHOULD TAKE IT RIGHT OVER SOUTHEAST KENTUCKY WITH THE WARM SECTOR SURGING INTO THE AREA LATE FRIDAY NIGHT. WHILE A PERIOD OF SNOW/SLEET MAY BE POSSIBLE AT THE ONSET...ESPECIALLY ACROSS THE NORTH...WE SHOULD SEE A QUICK TRANSITION OVER TO ALL RAIN. RAIN WILL CONTINUE INTO SATURDAY. AS THE SYSTEM DEPARTS...COLD AIR WILL WRAP BACK INTO EASTERN KENTUCKY WITH PRECIPITATION CHANGING OVER TO SNOW SATURDAY NIGHT. AT THIS TIME...MOISTURE AND LIFT APPEARS TO BE FAIRLY LIMITED WITH UPSLOPE FLOW...SO ANY ACCUMULATIONS WILL LIKELY BE SMALL AND MAYBE CONFINED TO JUST THE HIGHER ELEVATIONS. DRIER...BUT COLDER WEATHER WILL THEN BE SEEN INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 815 PM EST MON DEC 9 2013 CONFIDENCE IN THE DETAILS OF SNOW DEVELOPING ACROSS THE AREA OVERNIGHT HAS INCREASED WITH BETTER MODEL AGREEMENT...AND ALL SNOW IS ANTICIPATED AT THE TAF SITES. ACCORDINGLY...HAVE CONTINUED WITH A PERIOD OF LOW CIGS...AND VIS AT THE TAF SITES STARTING BETWEEN 6Z TO 9Z THROUGH ABOUT 13Z TO 16Z. MVFR CIGS ARE EXPECTED DURING THE FIRST 6 HOURS OF THE PERIOD...WITH IFR DURING THE PERIOD OF SNOW FALLING AND POSSIBLE AT LEAST BRIEF DROPS BELOW AIRPORT MINS DURING THE HEAVIEST SNOW. WINDS WILL BE WEST TO NORTHWEST THROUGH THE PERIOD AT 5 TO 10 KTS...BUT DURING ANY HEAVIER BOUTS OF SNOW THERE MAY BE A BRIEF PICK UP WITH GUSTS TO 15 KTS OR SO. CIGS SHOULD IMPROVE BACK TO MVFR BETWEEN 13Z AND 17Z AND THEN TO VFR LATE IN THE PERIOD AT ALL THE TAF SITES. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST TUESDAY FOR KYZ044-050>052. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST TUESDAY FOR KYZ058>060-068-069-079-080-083-084-104-106>109-111- 112-114. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST TUESDAY FOR KYZ085>088-110-113-115>120. && $$ SHORT TERM...GREIF LONG TERM...KAS AVIATION...JP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1220 PM EST Sun Dec 8 2013 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1212 PM EST Sun Dec 8 2013 Wintry mix has turned to rain in the south and has dissipated to just some patches of light freezing drizzle in the north/west, so have canceled the advisory for the Bowling Green and Louisville areas. Have replaced it with a Special Weather Statement for the light patchy FZDZ. Issued at 835 AM EST Sun Dec 8 2013 Ongoing winter weather event is panning out pretty much as expected thus far across the region. The latest reports that continue to filter in show up to 0.2 tenths of an inch of ice on trees and elevated surfaces, with perhaps up to 0.25 inch in isolated locations. The highest threat for icing up to 1/4 inch will be on a line from Logan/Butler counties northeast to Clark/Madison/Garrard counties. Thus far, reports indicate that side roads are a bit icy in these areas, but main roads seem to be doing okay. Given the short duration of the event (latest HRRR shows precip exiting most locations by 19Z) and locations receiving the icing now will likely get above freezing in the next couple of hours, will hold off on any ice storm warning product for now. Certainly a high-end advisory event in some areas, but impacts thus far continue to warrant leaving the advisory as is. Updates already out. .SHORT TERM (Now through Monday)... Issued at 300 AM EST Sun Dec 8 2013 ...A light wintry mix possible this morning...tending to change over to just light rain by afternoon across south central Kentucky... Upper air pattern shows a broad positively tilted trough across the Rockies, with southwesterly flow extending from Oklahoma through New England. Lift, associated with the right entrance region of a departing jet, coupled with moisture overrunning a nearly stationary boundary over Tennessee, will bring light mixed wintry precipitation this morning over central Kentucky. Forecast soundings show a warm layer around 850mb nosing northwards across southern Kentucky, and eventually into the Bluegrass. However, northeasterly winds will keep surface temperatures near freezing along the Tennessee border, and in the mid to upper 20s across central Kentucky. Light mixed sleet and freezing rain will overspread southern Kentucky during the predawn hours, and slowly move northeast towards the Bluegrass and along the Ohio River around dawn or shortly after. Towards Interstate 64, and across the Bluegrass, mixed precip may be preceded by a period of light snow, with minor accumulations. By noon, temperatures across our southern counties will slowly rise above freezing. Any mixed precip should change over to rain or just drizzle across the Bluegrass by mid to late afternoon. Along the Ohio River, where snowcover remains, temperatures will struggle to exceed freezing even by late afternoon. Will continue with a winter weather advisory for light sleet and icing across the central Commonwealth, and will likely allow it to expire by early afternoon across our southern counties. We should note that any icing or glaze will be light, as precipitation amounts will likely stay under 2 tenths of an inch near the Ohio River, ranging to maybe one half inch near the Lake Cumberland Region, where temperatures will first rise above freezing. Despite light precip amounts, any light glaze will adversely affect travel due to antecedent cold pavement and ground. Light precip will likely change over to just drizzle by mid-afternoon as moisture become more shallow by evening. Continued light rain may continue near Lake Cumberland, where a continued fetch of moisture from the southwest may allow steadier precipitation. Highs late this afternoon will range from the lower 40s near Lake Cumberland to the lower 30s across southern Indiana. As this first wave passes, moisture will become more shallow, but will continue saturated at low levels. So...expect cloudy skies this evening and overnight, with maybe even some light fog and drizzle. Temperatures won`t fall to much tonight, with lows not too far from freezing south and east of the Ohio River. Some partial clearing may arrive Monday afternoon, especially across southern Indiana, with highs remaining in the 30s. .LONG TERM (Monday Night through Saturday)... Issued at 255 AM EST Sun Dec 8 2013 This period will begin with surface high pressure ridging across or just north of the Ohio River. Aloft we will have a southwesterly flow with an elongated vortmax stretching from southeast Ontario to Oklahoma. Similar to yesterday`s 00Z model runs, today`s GFS/GEM/NAM all have precip across our southeast early Tuesday as well as a separate band of precip over southern Indiana, within the right entrance region of a 180kt upper jet centered over Lake Erie. This band, of what likely would be snow, is a little farther north than what was forecast yesterday. The repetition in features, as well as adding the new ECMWF into the mix, gives me enough of a signal to at least put in a slight chance of snow across my north early Tuesday and into the day. As for precip type across our southeast, that mostly looks like snow from a quick look at soundings. We may warm enough at the surface for a rain/snow mix. A quick look at forecast totals for now indicates a sub-advisory event. Another impulse moves through here Wednesday night, with a few of the models hinting at low QPF just to our north. May get some flurries out of this system across the north, but will leave forecast dry for now. High pressure on the back side of that system will shift east of our area Friday, allowing for some southerly winds to try and start a warmup for the weekend, at least closer to normal. With that warmup will come another surge in moisture, bringing precip chances back into the picture. Temperatures are at a range close enough to put in a rain/snow mix Friday night through Saturday. && .AVIATION (18Z TAF Update)... Updated at 1218 PM EST Sun Dec 8 2013 The wintry mix has become very light across the region this afternoon, but a prolonged period of IFR cigs or even LIFR cigs appears increasingly likely tonight. These LIFR ceilings have already moved into KBWG, and will likely affect KLEX as well. As another disturbance pushes in from the southwest overnight, additional low-level moisture will work into the region. This will cause ceilings to remain IFR or LIFR through the overnight period, with even a few light showers possible around KLEX or KBWG. KSDF will be further removed from the deeper moisture overnight, so just expect IFR cigs and perhaps some isolated drizzle. Winds will be shifting from easterly to southerly to westerly by Monday morning. Wind speeds will be generally light, around 7 knots or less. Ceilings should slowly improve throughout the day on Monday, lifting to MVFR thresholds by the mid to late morning hours. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY until 6 PM EST this evening FOR KYZ035>037-039>043-046>049-054>057. WINTER WEATHER ADVISORY until 3 PM EST this afternoon FOR KYZ067. IN...NONE. && $$ Update.........KJD/13 Short Term.....JSD Long Term......RJS Aviation.......KJD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1213 PM EST Sun Dec 8 2013 ...Forecast Update... Issued at 1212 PM EST Sun Dec 8 2013 Wintry mix has turned to rain in the south and has dissipated to just some patches of light freezing drizzle in the north/west, so have canceled the advisory for the Bowling Green and Louisville areas. Have replaced it with a Special Weather Statement for the light patchy FZDZ. Issued at 835 AM EST Sun Dec 8 2013 Ongoing winter weather event is panning out pretty much as expected thus far across the region. The latest reports that continue to filter in show up to 0.2 tenths of an inch of ice on trees and elevated surfaces, with perhaps up to 0.25 inch in isolated locations. The highest threat for icing up to 1/4 inch will be on a line from Logan/Butler counties northeast to Clark/Madison/Garrard counties. Thus far, reports indicate that side roads are a bit icy in these areas, but main roads seem to be doing okay. Given the short duration of the event (latest HRRR shows precip exiting most locations by 19Z) and locations receiving the icing now will likely get above freezing in the next couple of hours, will hold off on any ice storm warning product for now. Certainly a high-end advisory event in some areas, but impacts thus far continue to warrant leaving the advisory as is. Updates already out. .SHORT TERM (Now through Monday)... Issued at 300 AM EST Sun Dec 8 2013 ...A light wintry mix possible this morning...tending to change over to just light rain by afternoon across south central Kentucky... Upper air pattern shows a broad positively tilted trough across the Rockies, with southwesterly flow extending from Oklahoma through New England. Lift, associated with the right entrance region of a departing jet, coupled with moisture overrunning a nearly stationary boundary over Tennessee, will bring light mixed wintry precipitation this morning over central Kentucky. Forecast soundings show a warm layer around 850mb nosing northwards across southern Kentucky, and eventually into the Bluegrass. However, northeasterly winds will keep surface temperatures near freezing along the Tennessee border, and in the mid to upper 20s across central Kentucky. Light mixed sleet and freezing rain will overspread southern Kentucky during the predawn hours, and slowly move northeast towards the Bluegrass and along the Ohio River around dawn or shortly after. Towards Interstate 64, and across the Bluegrass, mixed precip may be preceded by a period of light snow, with minor accumulations. By noon, temperatures across our southern counties will slowly rise above freezing. Any mixed precip should change over to rain or just drizzle across the Bluegrass by mid to late afternoon. Along the Ohio River, where snowcover remains, temperatures will struggle to exceed freezing even by late afternoon. Will continue with a winter weather advisory for light sleet and icing across the central Commonwealth, and will likely allow it to expire by early afternoon across our southern counties. We should note that any icing or glaze will be light, as precipitation amounts will likely stay under 2 tenths of an inch near the Ohio River, ranging to maybe one half inch near the Lake Cumberland Region, where temperatures will first rise above freezing. Despite light precip amounts, any light glaze will adversely affect travel due to antecedent cold pavement and ground. Light precip will likely change over to just drizzle by mid-afternoon as moisture become more shallow by evening. Continued light rain may continue near Lake Cumberland, where a continued fetch of moisture from the southwest may allow steadier precipitation. Highs late this afternoon will range from the lower 40s near Lake Cumberland to the lower 30s across southern Indiana. As this first wave passes, moisture will become more shallow, but will continue saturated at low levels. So...expect cloudy skies this evening and overnight, with maybe even some light fog and drizzle. Temperatures won`t fall to much tonight, with lows not too far from freezing south and east of the Ohio River. Some partial clearing may arrive Monday afternoon, especially across southern Indiana, with highs remaining in the 30s. .LONG TERM (Monday Night through Saturday)... Issued at 255 AM EST Sun Dec 8 2013 This period will begin with surface high pressure ridging across or just north of the Ohio River. Aloft we will have a southwesterly flow with an elongated vortmax stretching from southeast Ontario to Oklahoma. Similar to yesterday`s 00Z model runs, today`s GFS/GEM/NAM all have precip across our southeast early Tuesday as well as a separate band of precip over southern Indiana, within the right entrance region of a 180kt upper jet centered over Lake Erie. This band, of what likely would be snow, is a little farther north than what was forecast yesterday. The repetition in features, as well as adding the new ECMWF into the mix, gives me enough of a signal to at least put in a slight chance of snow across my north early Tuesday and into the day. As for precip type across our southeast, that mostly looks like snow from a quick look at soundings. We may warm enough at the surface for a rain/snow mix. A quick look at forecast totals for now indicates a sub-advisory event. Another impulse moves through here Wednesday night, with a few of the models hinting at low QPF just to our north. May get some flurries out of this system across the north, but will leave forecast dry for now. High pressure on the back side of that system will shift east of our area Friday, allowing for some southerly winds to try and start a warmup for the weekend, at least closer to normal. With that warmup will come another surge in moisture, bringing precip chances back into the picture. Temperatures are at a range close enough to put in a rain/snow mix Friday night through Saturday. && .AVIATION (12Z TAF Update)... Updated at 607 AM EST Sun Dec 8 2013 Light mixed wintry precipitation will continue through the morning hours at SDF and LEX. For BWG, light freezing rain will switch to just light rain around 17z. Ceilings will lower to low end MVFR or to IFR within this precipitation For BWG, Light sleet and freezing rain will continue with IFR ceilings through the mid to late morning hours, after which, it will switch over to just light rain and diminish. Precipitation rates will stay light enough so that visibilities will stay in the upper MVFR range. Light drizzle with continued IFR ceilings are likely this afternoon. Cloudy skies and possibly light drizzle will continue overnight with IFR ceilings. For LEX, Light sleet, possibly mixed at first with light snow will be ongoing right around the TAF issuance time. Ceilings will lower to IFR by 14z and continue this way through much of the day. This will change into light freezing rain which will continue through the morning hours, eventually changing to light rain or drizzle by mid afternoon. IFR ceilings are likely this evening and overnight. For SDF, Light sleet and snow will continue through the morning hours...possibly changing to light freezing rain or freezing drizzle by early afternoon. Precipitation rates will stay light, so that ground-based visibilities will stay high in the MVFR or even VFR range today. IFR ceilings are expected this afternoon and tonight. Northeast winds of 5 to 10 mph tonight will veer to easterly by morning. Winds will become southerly at around 5 mph this evening. In general, for the overnight period and through early Monday, IFR ceilings and possibly some MVFR visibilities will continue even with a general lack of precipitation. Ceilings will rise into the MVFR category for all TAF sites by Monday afternoon as winds become westerly at 5 to 10mph after noon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY until 6 PM EST this evening FOR KYZ035>037-039>043-046>049-054>057. WINTER WEATHER ADVISORY until 3 PM EST this afternoon FOR KYZ067. IN...NONE. && $$ Update.........13/KJD Short Term.....JSD Long Term......RJS Aviation.......JSD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
837 AM EST Sun Dec 8 2013 ...Forecast Update... Issued at 835 AM EST Sun Dec 8 2013 Ongoing winter weather event is panning out pretty much as expected thus far across the region. The latest reports that continue to filter in show up to 0.2 tenths of an inch of ice on trees and elevated surfaces, with perhaps up to 0.25 inch in isolated locations. The highest threat for icing up to 1/4 inch will be on a line from Logan/Butler counties northeast to Clark/Madison/Garrard counties. Thus far, reports indicate that side roads are a bit icy in these areas, but main roads seem to be doing okay. Given the short duration of the event (latest HRRR shows precip exiting most locations by 19Z) and locations receiving the icing now will likely get above freezing in the next couple of hours, will hold off on any ice storm warning product for now. Certainly a high-end advisory event in some areas, but impacts thus far continue to warrant leaving the advisory as is. Will continue to monitor and upgrade if impacts begin to increase over the next hour or so. Updates already out. .SHORT TERM (Now through Monday)... Issued at 300 AM EST Sun Dec 8 2013 ...A light wintry mix possible this morning...tending to change over to just light rain by afternoon across south central Kentucky... Upper air pattern shows a broad positively tilted trough across the Rockies, with southwesterly flow extending from Oklahoma through New England. Lift, associated with the right entrance region of a departing jet, coupled with moisture overrunning a nearly stationary boundary over Tennessee, will bring light mixed wintry precipitation this morning over central Kentucky. Forecast soundings show a warm layer around 850mb nosing northwards across southern Kentucky, and eventually into the Bluegrass. However, northeasterly winds will keep surface temperatures near freezing along the Tennessee border, and in the mid to upper 20s across central Kentucky. Light mixed sleet and freezing rain will overspread southern Kentucky during the predawn hours, and slowly move northeast towards the Bluegrass and along the Ohio River around dawn or shortly after. Towards Interstate 64, and across the Bluegrass, mixed precip may be preceded by a period of light snow, with minor accumulations. By noon, temperatures across our southern counties will slowly rise above freezing. Any mixed precip should change over to rain or just drizzle across the Bluegrass by mid to late afternoon. Along the Ohio River, where snowcover remains, temperatures will struggle to exceed freezing even by late afternoon. Will continue with a winter weather advisory for light sleet and icing across the central Commonwealth, and will likely allow it to expire by early afternoon across our southern counties. We should note that any icing or glaze will be light, as precipitation amounts will likely stay under 2 tenths of an inch near the Ohio River, ranging to maybe one half inch near the Lake Cumberland Region, where temperatures will first rise above freezing. Despite light precip amounts, any light glaze will adversely affect travel due to antecedent cold pavement and ground. Light precip will likely change over to just drizzle by mid-afternoon as moisture become more shallow by evening. Continued light rain may continue near Lake Cumberland, where a continued fetch of moisture from the southwest may allow steadier precipitation. Highs late this afternoon will range from the lower 40s near Lake Cumberland to the lower 30s across southern Indiana. As this first wave passes, moisture will become more shallow, but will continue saturated at low levels. So...expect cloudy skies this evening and overnight, with maybe even some light fog and drizzle. Temperatures won`t fall to much tonight, with lows not too far from freezing south and east of the Ohio River. Some partial clearing may arrive Monday afternoon, especially across southern Indiana, with highs remaining in the 30s. .LONG TERM (Monday Night through Saturday)... Issued at 255 AM EST Sun Dec 8 2013 This period will begin with surface high pressure ridging across or just north of the Ohio River. Aloft we will have a southwesterly flow with an elongated vortmax stretching from southeast Ontario to Oklahoma. Similar to yesterday`s 00Z model runs, today`s GFS/GEM/NAM all have precip across our southeast early Tuesday as well as a separate band of precip over southern Indiana, within the right entrance region of a 180kt upper jet centered over Lake Erie. This band, of what likely would be snow, is a little farther north than what was forecast yesterday. The repetition in features, as well as adding the new ECMWF into the mix, gives me enough of a signal to at least put in a slight chance of snow across my north early Tuesday and into the day. As for precip type across our southeast, that mostly looks like snow from a quick look at soundings. We may warm enough at the surface for a rain/snow mix. A quick look at forecast totals for now indicates a sub-advisory event. Another impulse moves through here Wednesday night, with a few of the models hinting at low QPF just to our north. May get some flurries out of this system across the north, but will leave forecast dry for now. High pressure on the back side of that system will shift east of our area Friday, allowing for some southerly winds to try and start a warmup for the weekend, at least closer to normal. With that warmup will come another surge in moisture, bringing precip chances back into the picture. Temperatures are at a range close enough to put in a rain/snow mix Friday night through Saturday. && .AVIATION (00Z TAF Update)... Updated at 607 AM EST Sun Dec 8 2013 Light mixed wintry precipitation will continue through the morning hours at SDF and LEX. For BWG, light freezing rain will switch to just light rain around 17z. Ceilings will lower to low end MVFR or to IFR within this precipitation For BWG, Light sleet and freezing rain will continue with IFR ceilings through the mid to late morning hours, after which, it will switch over to just light rain and diminish. Precipitation rates will stay light enough so that visibilities will stay in the upper MVFR range. Light drizzle with continued IFR ceilings are likely this afternoon. Cloudy skies and possibly light drizzle will continue overnight with IFR ceilings. For LEX, Light sleet, possibly mixed at first with light snow will be ongoing right around the TAF issuance time. Ceilings will lower to IFR by 14z and continue this way through much of the day. This will change into light freezing rain which will continue through the morning hours, eventually changing to light rain or drizzle by mid afternoon. IFR ceilings are likely this evening and overnight. For SDF, Light sleet and snow will continue through the morning hours...possibly changing to light freezing rain or freezing drizzle by early afternoon. Precipitation rates will stay light, so that ground-based visibilities will stay high in the MVFR or even VFR range today. IFR ceilings are expected this afternoon and tonight. Northeast winds of 5 to 10 mph tonight will veer to easterly by morning. Winds will become southerly at around 5 mph this evening. In general, for the overnight period and through early Monday, IFR ceilings and possibly some MVFR visibilities will continue even with a general lack of precipitation. Ceilings will rise into the MVFR category for all TAF sites by Monday afternoon as winds become westerly at 5 to 10mph after noon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER WEATHER ADVISORY until 3 PM EST /2 PM CST/ this afternoon FOR KYZ061>067-070>078-081-082. WINTER WEATHER ADVISORY until 6 PM EST /5 PM CST/ this evening FOR KYZ023>043-045>049-053>057. IN...NONE. && $$ Update.........KJD Short Term.....JSD Long Term......RJS Aviation.......JSD
AREA FORECAST DISCUSSION
NWS CARIBOU ME
656 PM EST MON DEC 9 2013 .SYNOPSIS... LOW PRESSURE WILL MOVE AWAY TO THE EAST TONIGHT. A WEAK WAVE OF LOW PRESSURE WILL MOVE SOUTH OF THE REGION TUESDAY. A COLD FRONT WILL CROSS THE REGION WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY/... UPDATE: ADDED FREEZING DRIZZLE ACROSS THE CWA AS A DECENT DRY SLOT IS SHOWING UP ABOVE 750MBS. BELOW THIS LAYER WAS A SATURATED PROFILE W/A DECENT AREA OF WARM AIR W/A COLD DOME OF AIR AT THE SFC. THIS HAS SET THE STAGE FOR THE FREEZING DRIZZLE AND SPOTTY SLEET. RECEIVED SOME REPORTS AROUND THE REGION INCLUDING WAGM-TV IN PRESQUE ISLE OF FREEZING DRIZZLE. TEMPERATURES AT THE SFC ARE RUNNING IN THE MID AND UPPER TEENS ACROSS THE NORTH AND WEST WHILE MID TO UPPER 20S FOR INTERIOR DOWNEAST TO THE COAST. TEMPERATURES ALONG THE IMMEDIATE COAST WARMED INTO THE LOW TO MID 30S W/REPORTS OF LIGHT RAIN OR DRIZZLE. ADJUSTED SNOWFALL TOTALS DOWN FROM PREVIOUS FCST AS REPORTS SHOW NO MORE THAN 1-2 INCHES AT BEST AND THIS WAS FROM THE EARLIER BURST OF SNOW. THE 21Z RAP AND 18Z NAM INDICATE A RETURN OF SOME SNOW W/SOME ADDITIONAL ACCUMULATIONS, BUT WELL BELOW WHAT WAS PREVIOUS FCST. DECIDED TO GO FOR 2 TO 4 INCHES FOR A RANGE THROUGH MIDNIGHT. A FAST MOVING AND RATHER FLAT WAVE OF LOW PRESSURE LIFTING OUT OF THE MID ATLANTIC REGION ALONG A COLD FRONT WILL SLIDE SOUTH OF THE AREA ON TUESDAY. THIS MAY COME CLOSE ENOUGH TO BRING SOME PATCHY LIGHT RAIN OR SNOW ALONG THE IMMEDIATE COAST OR JUST OFFSHORE. THE SYSTEM OFFSHORE WILL QUICKLY MOVE AWAY TO THE EAST LATE TUESDAY WITH PARTIAL CLEARING DOWNEAST. SKIES ACROSS THE NORTH WILL REMAIN PARTLY TO MOSTLY CLOUDY ON TUESDAY. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A STRONG COLD FRONT WILL APPROACH NORTHWEST MAINE LATER TUESDAY NIGHT. EXPECT MOSTLY CLOUDY SKIES...WITH A CHANCE OF SNOW SHOWERS LATE...ACROSS NORTHERN AREAS WITH PARTLY CLOUDY SKIES DOWNEAST. THE COLD FRONT WILL CROSS THE REGION WEDNESDAY WITH A CHANCE OF SNOW SHOWERS. COULD HAVE LINGERING SNOW SHOWERS EARLY WEDNESDAY NIGHT. CLOUD COVER WILL THEN BEGIN TO DECREASE OVERNIGHT WEDNESDAY WHILE PRESSURE BUILDS TOWARD THE REGION. PARTLY CLOUDY SKIES AND MUCH COLDER TEMPERATURES WILL OCCUR ACROSS THE REGION THURSDAY. TEMPERATURES WILL BE AT BELOW NORMAL LEVELS WEDNESDAY...WITH MUCH BELOW NORMAL LEVEL TEMPERATURES THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... PERIOD WILL START OUT COLD AS SURFACE HIGH PRESSURE WILL CONTINUE TO NOSE NORTH THURSDAY NIGHT INTO FRIDAY. BOTH THE GFS AND ECMWF HAVE A WEAK LOW DEVELOPING ACROSS THE GREAT LAKES AND MOVING EAST. RIGHT NOW GFS IS STILL MOST ROBUST WITH QPF BUT THINKING MAIN IMPACT WILL BE INCREASED CLOUD COVER SATURDAY INTO SATURDAY NIGHT. MODELS DO INDICATE A LOW PRESSURE CONTINUING TO DEVELOP ACROSS THE CAROLINAS SATURDAY. THE MODELS HAVE SOME DIVERGENCE AS TO THE TIMING AND TRACK OF THIS SURFACE LOW. THIS IS DUE TO DIFFERENCES IN RELATION TO THE LOCATION AND INTENSITY OF THE CLOSED UPPER LEVEL LOW TO OUR EAST AND WHERE THE UPPER LEVEL JETS COUPLE. THE 06Z GFS KEEPS THIS SURFACE LOW WELL TO THE SOUTH BUT THE 00Z GFS ENSEMBLE MEAN BRINGS THE LOW OUT OF THE GREAT LAKES EAST. THE 00Z ECMWF IS A BIT SLOWER AND BRINGS LOW PRESSURE INTO THE GULF OF MAINE. IT SHOULD BE NOTED THE ECMWF ENSEMBLE MEAN IS IN PRETTY CLOSE AGREEMENT WITH THE OPERATIONAL RUN. THE 12Z GFS CAME MORE IN LINE WITH THE ECMWF ALTHOUGH A BIT FASTER. THE LATEST 12Z GFS IS HIGHEST WITH QPF ESPECIALLY DOWNEAST WITH THE POPS BEING ALL SNOW. THIS SYSTEM IS STILL LATE IN THE PERIOD WITH TIME TO RESOLVE TIMING AND LOCATION ISSUES. PLAN TO STICK WITH SUPERBLEND AT THIS POINT WITH SO MUCH MODEL UNCERTAINTY. DEPENDING ON TRACK OF THE LOW FOR SUNDAY IT COULD BE A BREEZY MONDAY ACROSS MAINE WITH TIGHTENING GRADIENT AND WRAP AROUND SNOW SHOWER ACROSS THE EASTERN PORTIONS OF MAINE. TEMPERATURES THROUGH THE PERIOD WILL BE BELOW NORMAL. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... NEAR TERM: IFR CONDITIONS IN LOW CLOUDS AND SOME PRECIPITATION THIS EVENING WILL IMPROVE TO MVFR AFTER MIDNIGHT THEN VFR ON TUESDAY. SHORT TERM: OCCASIONAL MVFR CONDITIONS ARE POSSIBLE ACROSS NORTHERN AREAS LATER TUESDAY NIGHT. OTHERWISE...VFR CONDITIONS ARE EXPECTED TUESDAY NIGHT. OCCASIONAL MVFR CONDITIONS ARE POSSIBLE ACROSS THE REGION WEDNESDAY INTO EARLY WEDNESDAY NIGHT. GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE REGION LATER WEDNESDAY NIGHT THROUGH FRIDAY. MVFR/IFR CONDITIONS COULD THEN DEVELOP SATURDAY. && .MARINE... NEAR TERM: AN SCA WILL BE EXTENDED THROUGH TUESDAY FOR WIND GUSTS OVER 25 KT. SOME SPOTTY LIGHT RAIN OR SNOW MAY AFFECT THE WATERS AGAIN ON TUESDAY. SHORT TERM: SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TUESDAY NIGHT THROUGH THURSDAY NIGHT. VISIBILITIES COULD BE REDUCED IN SNOW SHOWERS WEDNESDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MEZ001>006-010-011-015>017-031-032. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR ANZ050>052. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
600 PM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH SE CO. AT THE SFC...LIGHT WINDS PREVAILED ACROSS UPPER MICHIGAN AS ARCTIC HIGH PRES EXTENDED FROM NEW ENGLAND INTO THE NRN GREAT LAKES. A LOW PRES TROUGH STRETCHED FROM SW KS THROUGH THE OH VALLEY. A BROAD AREA OF LIGHT SNOW SUPPORTED BY WAA/280K-290K ISENTROPIC LIFT...HAD SPREAD FROM MN/IA/WI INTO UPPER MI. HOWEVER...SNOW HAS BEEN VERY LIGHT WITH VSBY TO 2-4SM FROM MNM-ESC AND ABOVE 5SM FROM IMT-IWD. LATE THIS AFTERNOON AND TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES EXPECT THE SNOW INTENSITY TO SLOWLY INCREASE. HOWEVER...WITH THE STRONGER 700-300 MB QVECTOR CONV REMAINING SOUTH OF THE AREA AND ONLY 1-2 G/KG AVAILABLE...GOING QPF VALUES IN THE 0.08-0.20 RANGE REMAIN ON TRACK. EXPECT SLR VALUES FROM NEAR 20/1 SOUTH TO 15/1 NORTH AS THE DGZ IS DEEPER AND EXTENDS MORE FAVORABLY INTO THE LAYER OF GREATER UPWARD MOTION OVER THE SOUTH COMPARED TO THE SHALLOW DGZ FARTHER NORTH IN THE COLDER AIR. SO...FCST SNOWFALL AMOUNTS OF AROUND AN INCH NORTH TO 1 TO 3 INCHES SOUTH ARE INCLUDED. THE HIGHER RES MODELS SUGGEST THAT AN AREA OF LOW LEVEL CONV OVER NRN LAKE MI AHEAD OF THE AREA OF STRONGER SE WINDS MAY PUSH A BAND OF LAKE ENHANCED SNOW INTO LOCATIONS BORDER THE BAY OF GREEN BAY AND LAKE MICHIGAN LATE THIS EVENING. SINCE THE BAND IS EXPECTED TO BE TRANSIENT...ADDITIONAL SNOW AMOUNTS OF ONLY AN INCH OR TWO ARE EXPECTED WITH THIS FEATURE. A PERIOD OF SRLY WINDS INTO SCHOOLCRAFT COUNTY COULD ALSO BRING A PERIOD OF MODERATE SNOW LATE TONIGHT. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. 850 MB TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8K-10K FT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN FAVORABLE LOW LEVEL CONV AND POTENTIAL FOR A DOMINANT LES BAND INTO THE NRN KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT THAT THE WINDS WOULD EVENTUALLY VEER...PUSHING THE BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON IN THE AFTERNOON. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...BUT 12 HOUR ACCUMULATIONS OF AT LEAST 8 INCHES REMAIN POSSIBLE. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND VERY LOW VSBY. HOWEVER...SINCE THE HIGHER RES MODELS STILL SHOW DIFFERENCES IN HANDLING WHERE THE BAND WILL DEVELOP AND HOW LONG IT WILL LINGER...THE WATCH WAS NOT UPGRADED AT THIS TIME. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 ELOGATED AREA OF UPPER LEVEL TROUGHING STRETCHES FROM SKANDINAVIA AND FAR NORTHWEST RUSSIA ACROSS THE NORTH POLE AND ACROSS MUCH OF EASTERN CANADA AND AS FAR SOUTH AS THE WESTERN PORTIONS OF THE CONUS. CORE OF COLDEST AIR RESIDES FROM NORTHERN GREENLAND ACROSS CNTRL CANADA AND INTO THE NORTHERN PLAINS. H85 TEMP THIS MORNING AT KINL WAS -25C WHILE IT WAS -17C AT KGRB. DECENT AGREEMENT THAT UPCOMING WEEK WILL REMAIN CHILLY AS UPPER TROUGH BECOMES MORE CENTERED OVER HUDSON BAY ALLOWING MULTIPLE PUSHES OF ARCTIC AIR TO SWEEP ACROSS NORTHERN PLAINS AND GREAT LAKES IN NW FLOW ALOFT. STILL INDICATIONS THAT COLD STARTS TO RELAX NEXT WEEKEND AS TROUGHING REORIENTS FROM NORTH POLE TO DAVIS STRAIT AND GREENLAND WHICH ALLOWS FOR MORE OF A ZONAL WEST-NORTHWEST FLOW ALOFT ACROSS THE CONUS BY MIDDLE OF THE MONTH. FIRST CONCERNING THE LK EFFECT ON MONDAY NIGHT. INITIAL SHORTWAVE IN NW FLOW CURRENTLY OVER NORTHERN SASKATCHEWAN AND MANITOBA SWEEPS ACROSS LK SUPERIOR REGION MONDAY AFTN. EXPECT MINIMAL SYNOPTIC SUPPORT FOR ANY SNOW AS PVA/Q-VECTOR CONVERGENCE AT H7-H5/H85-H7 STAYS OVER LK SUPERIOR AND MAINLY NORTH. SFC LOW MOVING THROUGH ON MONDAY DEEPENS NORTH OF LK SUPERIOR TOWARD JAMES BAY BY MONDAY EVENING AS RESULT OF PVA/COLD AIR ADVECTION. RESULT IS INCREASING UNSTABLE WESTERLY LOW- LEVEL FLOW ACROSS LK SUPERIOR. NAM SOUNDINGS INDICATE VERY UNSTABLE CONDITIONS AS SHORTWAVE HELPS RAISE INVERSIONS TO OVER 7KFT WITH LAKE EQL/S OVER 13KFT AT CMX AND P59 AND STDM4. SFC-925MB STEERING WINDS VARY ENOUGH DURING PERIOD OF MOST FAVORABLE INSTABILITY/MOSITURE/CONVERGENCE TO PEG WHERE HEAVIEST SNOW WILL OCCUR. HIGH RES MODELS DO DIFFER HERE SOMEWHAT...WITH THE 12Z REGIONAL GEM KEEPING THE STRONGEST CONVERGENCE MAINLY ALONG THE NORTHWEST SHORE OF THE KEWEENAW THROUGH LATE AFTN...WHILE LOCAL WRF IS MORE ON THE SOUTHERN EDGE...SETTING UP DOMINANT BAND MAINLY TO SOUTH OF HOUGHTON AND HANCOCK. NAM AND NCEP WRF-ARW/NMM NESTS KIND OF IN BTWN THOSE IDEAS. GIVEN THE DEGREE OF OVERWATER INSTABILITY... POTENTIAL CERTAINTY THERE FOR TOTAL SNOW MONDAY AFTN THROUGH MONDAY EVENING TO EXCEED A FOOT...IF THE BAND CAN PERSIST IN ONE LOCATION FOR A WHILE. AT THE LEAST...MOST AREAS WILL SEE BURSTS OF HEAVIER SNOW ALONG WITH STRONG/GUSTY WEST WINDS TO 40 MPH AND A LOT OF BLOWING SNOW AND POOR VSBY. IN THE HEAVIER SNOW BAND...WHITEOUTS MAY OCCUR MONDAY AFTN INTO MONDAY EVENING. COORD WITH SHORT TERM FORECASTER AND DECIDED TO LEAVE GOING LK EFFECT SNOW WATCH. NOT REALLY A QUESTION IF HEAVY LES/BLSN WILL OCCUR...BUT MORE ONE OF WHERE THAT STRONG CONVERGENCE BAND WILL DEVELOP. WILL LET MID SHIFT TAKE ANOTHER CRACK AT PINNING DOWN LOCATION OF THE HEAVIER SNOW BAND. ATTN LATER MONDAY NIGHT WILL BE ON SHORTWAVE PUSHING IN ACROSS NORTHERN PLAINS AND ASSOCIATED SFC TROUGH. FIRST IMPACT FM THIS WAVE WILL BE TO BACK WINDS SW...ALLOWING MOST OF HEAVIER LK EFFECT SNOW TO PUSH OUT OVER LK SUPERIOR OFF THE KEWEENAW PENINSULA...THUS THE ENDING TIME OF LATE MONDAY EVENING FOR LAKE EFFECT SNOW WATCH. RIGHT AS THE LK EFFECT DIMINISHES FOR A WHILE...STILL APPEARS THAT LGT SYNOPTIC SNOW WILL IMPACT MUCH OF CWA MAINLY IN THE MORNING. BRIEF NOTE ABOUT WIND CHILLS FOR MONDAY NIGHT...INCREASING CLOUDS AHEAD OF THE SYSTEM LATER MONDAY NIGHT SHOULD ALLOW TEMPS TO BEGIN TO RISE. HAVE MINS WELL BLO ZERO...EVEN LESS THAN 10 BLO THROUGH EARLY MORNING...THEN WITH THE ARRIVAL OF CLOUDS AND MORE WIND...EXPECT TEMPS TO RISE TOWARD ZERO BY DAYBREAK ON TUESDAY. WILL BE CLOSE CALL ON WIND CHILL READINGS NEAR CRITERIA BUT TEMPS MAY WARM JUST ENOUGH TO KEEP WIND CHILLS GREATER THAN 25 BLO. AT THE LEAST...WIND CHILLS WILL STILL BE A RATHER CHILLY 10 TO 20 BLO FOR MAJORITY OF WEST HALF OF UPR MICHIGAN. AS SFC LOW STRENGTHENS...MOISTURE/TEMPERATURE ADVECTION AHEAD OF WAVE MIGHT RESULT IN MORE WIDESPREAD SNOW OVER EASTERN CWA LATE MORNING INTO EARLY AFTN...WHERE A FEW INCHES OF SNOW COULD OCCUR. OTHERWISE...EXPECT LESS THAN 1 INCH FOR THE CWA FROM THE SYSTEM. ONCE THE SHORTWAVE AND SFC LOW CROSS THE AREA...SFC TROUGH ELONGATES ACROSS SOUTHERN HALF OF LK SUPERIOR AND EVENTUALLY INTO NORTHERN TIER OF UPR MICHIGAN. RESULT WILL BE LK EFFECT...MOSTLY OF MODERATE INTENSITY...FOR THE WNW-NW FLOW AREAS. MOST CONCENTRATED/HEAVIER SNOW SHOWERS LIKELY FOR THE SNOWBELTS OF ONTONAGON COUNTY FROM WHITE PINE TO ROCKLAND AND ALSO TO THE EAST OF MUNISING AND TO THE NORTH OF NEWBERRY...INCLUDING GRAND MARAIS. PERSISTENT LK EFFECT SETUP CONTINUES THROUGH MUCH OF WEDNESDAY WITH INVERSIONS 5-8KFT AND MORE THAN SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS ARE NEAR -25C. GIVEN SUCH COLD TEMPS THOUGH...SNOW WILL BE VERY FINE AND MAIN ISSUE IN THE LK EFFECT AREAS WILL BE POWDERY SNOW BEING BLOWN AROUND BY GUSTY WINDS RESULTING IN BLSN/POOR VSBY. AWAY FM THE LK EFFECT COLD AIRMASS FIRMLY ENTRENCHED. SOME AREAS OF WESTERN CWA MAY NOT REACH ZERO ON WEDNESDAY AFTN. ANOTHER SYSTEM APPROACHING IN THE ACTIVE NW FLOW ALOFT COMES IN BY THURSDAY MORNING. WINDS SHOULD BACK ENOUGH SW TO PUSH MOST OF THE LK EFFECT OFFSHORE EXCEPT OVER THE KEWEENAW. HIGH PRESSURE RIDGE IN VCNTY FIRST PART OF WED NIGHT WITH SUCH COLD AIRMASS SUGGESTS THAT MINS COULD BE VERY LOW. LOWERED TEMPS TOWARD COLDER MOS NUMBERS...AND FURTHER TWEAKED COLD SPOTS IN THE INTERIOR TOWARD 20 BLO ZERO. MAY BE SIMILAR SETUP TO MONDAY NIGHT/TUESDAY NIGHT WHERE TEMPS RISE LATE. MAIN CHANGE BESIDES LOWERING TEMPS WAS TO LOWER WIND SPEEDS TOO AS WINDS MAY TRY TO GO CALM WITH THE RIDGE AROUND TO START THE NIGHT. THUS...MAY NOT SEE WIND CHILL ISSUES UNLESS THAT INCOMING SYSTEM TRENDS STRONGER. IN WAKE OF THAT SYSTEM...SFC TROUGH SINKS ACROSS LK SUPERIOR AND UPR MICHIGAN WHICH TURNS WINDS MORE NNW/N LATER THURSDAY AND FRIDAY. KEPT IDEA OF INCREASING POPS FOR LK EFFECT ALONG MUCH OF LK SUPERIOR COMPARED TO CONSENSUS POPS. MODELS HINT THAT WARMER AIR COULD TRY TO WORK IN BY NEXT WEEKEND...AT LEAST RELATIVELY WARMER...AS FLOW SHOWS SIGNS OF TRYING TO BECOME MORE ZONAL. MORE WIDESPREAD AREA OF WARM AIR ADVECTION SNOW MAY TRY TO DEVELOP CLOSE TO THE REGION ALONG RETREATING ARCTIC AIRMASS. THOSE TYPE OF DETAILS WILL BE HANDLED BY LOW CHANCE POPS FOR THE TIME BEING. TEMPS THOUGH WARMER WILL STILL BE RUNNING BLO NORMAL THROUGH THE END OF THE EXTENDED. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 600 PM EST SUN DEC 8 2013 WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS CONTINUING. IFR CONDITIONS ARE MOST LIKELY TO DEVELOP AT SAW. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH VLIFR VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST AND BECOME GUSTY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 400 PM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE ANOTHER ROUND OF GALES TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 9 AM EST MONDAY FOR MIZ007-014-085. LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM MONDAY TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ244-245- 265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ MONDAY TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264. GALE WARNING FROM 4 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM MONDAY TO MIDNIGHT EST MONDAY NIGHT FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 PM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH SE CO. AT THE SFC...LIGHT WINDS PREVAILED ACROSS UPPER MICHIGAN AS ARCTIC HIGH PRES EXTENDED FROM NEW ENGLAND INTO THE NRN GREAT LAKES. A LOW PRES TROUGH STRETCHED FROM SW KS THROUGH THE OH VALLEY. A BROAD AREA OF LIGHT SNOW SUPPORTED BY WAA/280K-290K ISENTROPIC LIFT...HAD SPREAD FROM MN/IA/WI INTO UPPER MI. HOWEVER...SNOW HAS BEEN VERY LIGHT WITH VSBY TO 2-4SM FROM MNM-ESC AND ABOVE 5SM FROM IMT-IWD. LATE THIS AFTERNOON AND TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES EXPECT THE SNOW INTENSITY TO SLOWLY INCREASE. HOWEVER...WITH THE STRONGER 700-300 MB QVECTOR CONV REMAINING SOUTH OF THE AREA AND ONLY 1-2 G/KG AVAILABLE...GOING QPF VALUES IN THE 0.08-0.20 RANGE REMAIN ON TRACK. EXPECT SLR VALUES FROM NEAR 20/1 SOUTH TO 15/1 NORTH AS THE DGZ IS DEEPER AND EXTENDS MORE FAVORABLY INTO THE LAYER OF GREATER UPWARD MOTION OVER THE SOUTH COMPARED TO THE SHALLOW DGZ FARTHER NORTH IN THE COLDER AIR. SO...FCST SNOWFALL AMOUNTS OF AROUND AN INCH NORTH TO 1 TO 3 INCHES SOUTH ARE INCLUDED. THE HIGHER RES MODELS SUGGEST THAT AN AREA OF LOW LEVEL CONV OVER NRN LAKE MI AHEAD OF THE AREA OF STRONGER SE WINDS MAY PUSH A BAND OF LAKE ENHANCED SNOW INTO LOCATIONS BORDER THE BAY OF GREEN BAY AND LAKE MICHIGAN LATE THIS EVENING. SINCE THE BAND IS EXPECTED TO BE TRANSIENT...ADDITIONAL SNOW AMOUNTS OF ONLY AN INCH OR TWO ARE EXPECTED WITH THIS FEATURE. A PERIOD OF SRLY WINDS INTO SCHOOLCRAFT COUNTY COULD ALSO BRING A PERIOD OF MODERATE SNOW LATE TONIGHT. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. 850 MB TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8K-10K FT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN FAVORABLE LOW LEVEL CONV AND POTENTIAL FOR A DOMINANT LES BAND INTO THE NRN KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT THAT THE WINDS WOULD EVENTUALLY VEER...PUSHING THE BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON IN THE AFTERNOON. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...BUT 12 HOUR ACCUMULATIONS OF AT LEAST 8 INCHES REMAIN POSSIBLE. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND VERY LOW VSBY. HOWEVER...SINCE THE HIGHER RES MODELS STILL SHOW DIFFERENCES IN HANDLING WHERE THE BAND WILL DEVELOP AND HOW LONG IT WILL LINGER...THE WATCH WAS NOT UPGRADED AT THIS TIME. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 400 PM EST SUN DEC 8 2013 ELOGATED AREA OF UPPER LEVEL TROUGHING STRETCHES FROM SKANDINAVIA AND FAR NORTHWEST RUSSIA ACROSS THE NORTH POLE AND ACROSS MUCH OF EASTERN CANADA AND AS FAR SOUTH AS THE WESTERN PORTIONS OF THE CONUS. CORE OF COLDEST AIR RESIDES FROM NORTHERN GREENLAND ACROSS CNTRL CANADA AND INTO THE NORTHERN PLAINS. H85 TEMP THIS MORNING AT KINL WAS -25C WHILE IT WAS -17C AT KGRB. DECENT AGREEMENT THAT UPCOMING WEEK WILL REMAIN CHILLY AS UPPER TROUGH BECOMES MORE CENTERED OVER HUDSON BAY ALLOWING MULTIPLE PUSHES OF ARCTIC AIR TO SWEEP ACROSS NORTHERN PLAINS AND GREAT LAKES IN NW FLOW ALOFT. STILL INDICATIONS THAT COLD STARTS TO RELAX NEXT WEEKEND AS TROUGHING REORIENTS FROM NORTH POLE TO DAVIS STRAIT AND GREENLAND WHICH ALLOWS FOR MORE OF A ZONAL WEST-NORTHWEST FLOW ALOFT ACROSS THE CONUS BY MIDDLE OF THE MONTH. FIRST CONCERNING THE LK EFFECT ON MONDAY NIGHT. INITIAL SHORTWAVE IN NW FLOW CURRENTLY OVER NORTHERN SASKATCHEWAN AND MANITOBA SWEEPS ACROSS LK SUPERIOR REGION MONDAY AFTN. EXPECT MINIMAL SYNOPTIC SUPPORT FOR ANY SNOW AS PVA/Q-VECTOR CONVERGENCE AT H7-H5/H85-H7 STAYS OVER LK SUPERIOR AND MAINLY NORTH. SFC LOW MOVING THROUGH ON MONDAY DEEPENS NORTH OF LK SUPERIOR TOWARD JAMES BAY BY MONDAY EVENING AS RESULT OF PVA/COLD AIR ADVECTION. RESULT IS INCREASING UNSTABLE WESTERLY LOW- LEVEL FLOW ACROSS LK SUPERIOR. NAM SOUNDINGS INDICATE VERY UNSTABLE CONDITIONS AS SHORTWAVE HELPS RAISE INVERSIONS TO OVER 7KFT WITH LAKE EQL/S OVER 13KFT AT CMX AND P59 AND STDM4. SFC-925MB STEERING WINDS VARY ENOUGH DURING PERIOD OF MOST FAVORABLE INSTABILITY/MOSITURE/CONVERGENCE TO PEG WHERE HEAVIEST SNOW WILL OCCUR. HIGH RES MODELS DO DIFFER HERE SOMEWHAT...WITH THE 12Z REGIONAL GEM KEEPING THE STRONGEST CONVERGENCE MAINLY ALONG THE NORTHWEST SHORE OF THE KEWEENAW THROUGH LATE AFTN...WHILE LOCAL WRF IS MORE ON THE SOUTHERN EDGE...SETTING UP DOMINANT BAND MAINLY TO SOUTH OF HOUGHTON AND HANCOCK. NAM AND NCEP WRF-ARW/NMM NESTS KIND OF IN BTWN THOSE IDEAS. GIVEN THE DEGREE OF OVERWATER INSTABILITY... POTENTIAL CERTAINTY THERE FOR TOTAL SNOW MONDAY AFTN THROUGH MONDAY EVENING TO EXCEED A FOOT...IF THE BAND CAN PERSIST IN ONE LOCATION FOR A WHILE. AT THE LEAST...MOST AREAS WILL SEE BURSTS OF HEAVIER SNOW ALONG WITH STRONG/GUSTY WEST WINDS TO 40 MPH AND A LOT OF BLOWING SNOW AND POOR VSBY. IN THE HEAVIER SNOW BAND...WHITEOUTS MAY OCCUR MONDAY AFTN INTO MONDAY EVENING. COORD WITH SHORT TERM FORECASTER AND DECIDED TO LEAVE GOING LK EFFECT SNOW WATCH. NOT REALLY A QUESTION IF HEAVY LES/BLSN WILL OCCUR...BUT MORE ONE OF WHERE THAT STRONG CONVERGENCE BAND WILL DEVELOP. WILL LET MID SHIFT TAKE ANOTHER CRACK AT PINNING DOWN LOCATION OF THE HEAVIER SNOW BAND. ATTN LATER MONDAY NIGHT WILL BE ON SHORTWAVE PUSHING IN ACROSS NORTHERN PLAINS AND ASSOCIATED SFC TROUGH. FIRST IMPACT FM THIS WAVE WILL BE TO BACK WINDS SW...ALLOWING MOST OF HEAVIER LK EFFECT SNOW TO PUSH OUT OVER LK SUPERIOR OFF THE KEWEENAW PENINSULA...THUS THE ENDING TIME OF LATE MONDAY EVENING FOR LAKE EFFECT SNOW WATCH. RIGHT AS THE LK EFFECT DIMINISHES FOR A WHILE...STILL APPEARS THAT LGT SYNOPTIC SNOW WILL IMPACT MUCH OF CWA MAINLY IN THE MORNING. BRIEF NOTE ABOUT WIND CHILLS FOR MONDAY NIGHT...INCREASING CLOUDS AHEAD OF THE SYSTEM LATER MONDAY NIGHT SHOULD ALLOW TEMPS TO BEGIN TO RISE. HAVE MINS WELL BLO ZERO...EVEN LESS THAN 10 BLO THROUGH EARLY MORNING...THEN WITH THE ARRIVAL OF CLOUDS AND MORE WIND...EXPECT TEMPS TO RISE TOWARD ZERO BY DAYBREAK ON TUESDAY. WILL BE CLOSE CALL ON WIND CHILL READINGS NEAR CRITERIA BUT TEMPS MAY WARM JUST ENOUGH TO KEEP WIND CHILLS GREATER THAN 25 BLO. AT THE LEAST...WIND CHILLS WILL STILL BE A RATHER CHILLY 10 TO 20 BLO FOR MAJORITY OF WEST HALF OF UPR MICHIGAN. AS SFC LOW STRENGTHENS...MOISTURE/TEMPERATURE ADVECTION AHEAD OF WAVE MIGHT RESULT IN MORE WIDESPREAD SNOW OVER EASTERN CWA LATE MORNING INTO EARLY AFTN...WHERE A FEW INCHES OF SNOW COULD OCCUR. OTHERWISE...EXPECT LESS THAN 1 INCH FOR THE CWA FROM THE SYSTEM. ONCE THE SHORTWAVE AND SFC LOW CROSS THE AREA...SFC TROUGH ELONGATES ACROSS SOUTHERN HALF OF LK SUPERIOR AND EVENTUALLY INTO NORTHERN TIER OF UPR MICHIGAN. RESULT WILL BE LK EFFECT...MOSTLY OF MODERATE INTENSITY...FOR THE WNW-NW FLOW AREAS. MOST CONCENTRATED/HEAVIER SNOW SHOWERS LIKELY FOR THE SNOWBELTS OF ONTONAGON COUNTY FROM WHITE PINE TO ROCKLAND AND ALSO TO THE EAST OF MUNISING AND TO THE NORTH OF NEWBERRY...INCLUDING GRAND MARAIS. PERSISTENT LK EFFECT SETUP CONTINUES THROUGH MUCH OF WEDNESDAY WITH INVERSIONS 5-8KFT AND MORE THAN SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS ARE NEAR -25C. GIVEN SUCH COLD TEMPS THOUGH...SNOW WILL BE VERY FINE AND MAIN ISSUE IN THE LK EFFECT AREAS WILL BE POWDERY SNOW BEING BLOWN AROUND BY GUSTY WINDS RESULTING IN BLSN/POOR VSBY. AWAY FM THE LK EFFECT COLD AIRMASS FIRMLY ENTRENCHED. SOME AREAS OF WESTERN CWA MAY NOT REACH ZERO ON WEDNESDAY AFTN. ANOTHER SYSTEM APPROACHING IN THE ACTIVE NW FLOW ALOFT COMES IN BY THURSDAY MORNING. WINDS SHOULD BACK ENOUGH SW TO PUSH MOST OF THE LK EFFECT OFFSHORE EXCEPT OVER THE KEWEENAW. HIGH PRESSURE RIDGE IN VCNTY FIRST PART OF WED NIGHT WITH SUCH COLD AIRMASS SUGGESTS THAT MINS COULD BE VERY LOW. LOWERED TEMPS TOWARD COLDER MOS NUMBERS...AND FURTHER TWEAKED COLD SPOTS IN THE INTERIOR TOWARD 20 BLO ZERO. MAY BE SIMILAR SETUP TO MONDAY NIGHT/TUESDAY NIGHT WHERE TEMPS RISE LATE. MAIN CHANGE BESIDES LOWERING TEMPS WAS TO LOWER WIND SPEEDS TOO AS WINDS MAY TRY TO GO CALM WITH THE RIDGE AROUND TO START THE NIGHT. THUS...MAY NOT SEE WIND CHILL ISSUES UNLESS THAT INCOMING SYSTEM TRENDS STRONGER. IN WAKE OF THAT SYSTEM...SFC TROUGH SINKS ACROSS LK SUPERIOR AND UPR MICHIGAN WHICH TURNS WINDS MORE NNW/N LATER THURSDAY AND FRIDAY. KEPT IDEA OF INCREASING POPS FOR LK EFFECT ALONG MUCH OF LK SUPERIOR COMPARED TO CONSENSUS POPS. MODELS HINT THAT WARMER AIR COULD TRY TO WORK IN BY NEXT WEEKEND...AT LEAST RELATIVELY WARMER...AS FLOW SHOWS SIGNS OF TRYING TO BECOME MORE ZONAL. MORE WIDESPREAD AREA OF WARM AIR ADVECTION SNOW MAY TRY TO DEVELOP CLOSE TO THE REGION ALONG RETREATING ARCTIC AIRMASS. THOSE TYPE OF DETAILS WILL BE HANDLED BY LOW CHANCE POPS FOR THE TIME BEING. TEMPS THOUGH WARMER WILL STILL BE RUNNING BLO NORMAL THROUGH THE END OF THE EXTENDED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1218 PM EST SUN DEC 8 2013 A DISTURBANCE AND WIDESPREAD AREA OF LIGHT SNOW WILL MOVE FROM WI INTO UPPER MICHIGAN THIS AFTERNOON. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTERNOON...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH LIFR VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 400 PM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE ANOTHER ROUND OF GALES TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM MONDAY TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ244-245- 265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ MONDAY TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264. GALE WARNING FROM 4 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM MONDAY TO MIDNIGHT EST MONDAY NIGHT FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1219 PM EST SUN DEC 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 601 AM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH UTAH EARLY THIS MORNING AND THIS FEATURE WILL BRING A SHOT OF WIDESPREAD SYSTEM SNOW TO MUCH OF THE AREA TONIGHT INTO EARLY MONDAY. STRONG SFC HIGH PRESSURE CENTERED JUST SOUTH OF OUR AREA INTO WISCONSIN HAS RESULTED IN VERY COLD TEMPS (5 TO 15 BELOW ZERO) EARLY THIS MORNING...ESPECIALLY ACROSS THE WESTERN INTERIOR OF UPPER MICHIGAN. NOT MUCH WIND ACCOMPANYING THESE COLD TEMPS SO WENT AHEAD AND CANCELLED THE WIND CHILL ADVISORY FOR THE WESTERN INTERIOR CWA. WIND PARALLEL LES BANDS STILL IMPACTING THE KEWEENAW PENINSULA AND ERN SHORELINE AREAS EARLY THIS MORNING IN CONVERGENT LOW-LVL WESTERLY FLOW. WOULD NOT BE SURPRISED IF THESE AREAS ESPECIALLY THE KEWEENAW RECEIVED AN ADDITIONAL 3 TO 5 INCHES OF LES OVERNIGHT. TODAY...ANY REMAINING LES IS EXPECTED TO LIFT NORTH OF THE KEWEENAW AND THE SHORELINES OF THE ERN COUNTIES AS WINDS BEGIN TO BACK SW IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 275K-285K ISENTROPIC LIFT AHEAD OF SHORTWAVE LIFTING OUT OF THE WRN CONUS TROF WILL SPREAD LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH BY EARLY AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z WILL BE RELATIVELY LIGHT...GENERALLY A HALF INCH OR LESS MOST AREAS WITH MAYBE UP TO AN INCH SOUTH CENTRAL ALONG LAKE MI CLOSER TO BEST ISENTROPIC LIFT AND Q-VECT CONV. TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES FORCING IN LEFT EXIT REGION OF UPPER JET AND ASSOC 700-600 MB FGEN RESPONSE ALONG WITH NOTED MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV OFF CROSS SECTIONS COULD RESULT IN HEAVIER BANDED SNOW OVER SE COUNTIES. ENHANCEMENT TO SYSTEM SNOW IS ALSO POSSIBLE NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE SHIFTING SOUTH THROUGH THE NIGHT /E WINDS IN LOW-LEVELS WITH 8H TEMPS AROUND -12C AND LK MICHIGAN WATER TEMPS AROUND +5C. BIGGEST LIMITING FACTOR FOR LAKE ENHANCED SNOW WILL BE SHIFTING WIND DIRECTION. EXPECT GENERAL 1-3" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S AROUND 18:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEM UNLIKELY DUE TO BEST LIFT OCCURING ABV DGZ. COULD SEE ANOTHER 1-2 OF LAKE ENHANCEMENT ON TOP OF SYSTEM SNOW PUSHING TOTAL SNOW AMOUNTS INTO LOW END ADVISORY CATEGORY WITH 4-5 INCHES. AS A RESULT...WILL CONTINUE THE WINTER WX ADVISORY FOR SE AND ERN COUNTIES TONIGHT INTO EARLY MONDAY. FARTHER WEST GENERALLY EXPECT NO MORE THAN 1-2 INCHES OF TOTAL SNOWFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 601 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1218 PM EST SUN DEC 8 2013 A DISTURBANCE AND WIDESPREAD AREA OF LIGHT SNOW WILL MOVE FROM WI INTO UPPER MICHIGAN THIS AFTERNOON. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTERNOON...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH LIFR VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 601 AM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS THE EAST HALF OF LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE WESTERLY WINDS OF UP TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. GALE WATCH FROM MONDAY AFTERNOON THROUGH LATE MONDAY NIGHT FOR LSZ244-245. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...JLB MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 AM EST SUN DEC 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 601 AM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH UTAH EARLY THIS MORNING AND THIS FEATURE WILL BRING A SHOT OF WIDESPREAD SYSTEM SNOW TO MUCH OF THE AREA TONIGHT INTO EARLY MONDAY. STRONG SFC HIGH PRESSURE CENTERED JUST SOUTH OF OUR AREA INTO WISCONSIN HAS RESULTED IN VERY COLD TEMPS (5 TO 15 BELOW ZERO) EARLY THIS MORNING...ESPECIALLY ACROSS THE WESTERN INTERIOR OF UPPER MICHIGAN. NOT MUCH WIND ACCOMPANYING THESE COLD TEMPS SO WENT AHEAD AND CANCELLED THE WIND CHILL ADVISORY FOR THE WESTERN INTERIOR CWA. WIND PARALLEL LES BANDS STILL IMPACTING THE KEWEENAW PENINSULA AND ERN SHORELINE AREAS EARLY THIS MORNING IN CONVERGENT LOW-LVL WESTERLY FLOW. WOULD NOT BE SURPRISED IF THESE AREAS ESPECIALLY THE KEWEENAW RECEIVED AN ADDITIONAL 3 TO 5 INCHES OF LES OVERNIGHT. TODAY...ANY REMAINING LES IS EXPECTED TO LIFT NORTH OF THE KEWEENAW AND THE SHORELINES OF THE ERN COUNTIES AS WINDS BEGIN TO BACK SW IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 275K-285K ISENTROPIC LIFT AHEAD OF SHORTWAVE LIFTING OUT OF THE WRN CONUS TROF WILL SPREAD LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH BY EARLY AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z WILL BE RELATIVELY LIGHT...GENERALLY A HALF INCH OR LESS MOST AREAS WITH MAYBE UP TO AN INCH SOUTH CENTRAL ALONG LAKE MI CLOSER TO BEST ISENTROPIC LIFT AND Q-VECT CONV. TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES FORCING IN LEFT EXIT REGION OF UPPER JET AND ASSOC 700-600 MB FGEN RESPONSE ALONG WITH NOTED MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV OFF CROSS SECTIONS COULD RESULT IN HEAVIER BANDED SNOW OVER SE COUNTIES. ENHANCEMENT TO SYSTEM SNOW IS ALSO POSSIBLE NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE SHIFTING SOUTH THROUGH THE NIGHT /E WINDS IN LOW-LEVELS WITH 8H TEMPS AROUND -12C AND LK MICHIGAN WATER TEMPS AROUND +5C. BIGGEST LIMITING FACTOR FOR LAKE ENHANCED SNOW WILL BE SHIFTING WIND DIRECTION. EXPECT GENERAL 1-3" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S AROUND 18:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEM UNLIKELY DUE TO BEST LIFT OCCURING ABV DGZ. COULD SEE ANOTHER 1-2 OF LAKE ENHANCEMENT ON TOP OF SYSTEM SNOW PUSHING TOTAL SNOW AMOUNTS INTO LOW END ADVISORY CATEGORY WITH 4-5 INCHES. AS A RESULT...WILL CONTINUE THE WINTER WX ADVISORY FOR SE AND ERN COUNTIES TONIGHT INTO EARLY MONDAY. FARTHER WEST GENERALLY EXPECT NO MORE THAN 1-2 INCHES OF TOTAL SNOWFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 601 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 635 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND SSW DIRECTION AT KSAW/KIWD WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KCMX...LAKE EFFECT SNOW WILL DIMINISH/END IN THE NEXT FEW HOURS AS BACKING WINDS PUSH LES OFFSHORE AND CONDITIONS IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. EXPECT IMPROVEMENT IN VSBY TO VFR LATE TONIGHT AT KIWD AS BACK EDGE OF PCPN/SNOW SHIELD LIFTS NORTH. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 601 AM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS THE EAST HALF OF LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE WESTERLY WINDS OF UP TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...VOSS MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
602 AM EST SUN DEC 8 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 601 AM EST SUN DEC 8 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH UTAH EARLY THIS MORNING AND THIS FEATURE WILL BRING A SHOT OF WIDESPREAD SYSTEM SNOW TO MUCH OF THE AREA TONIGHT INTO EARLY MONDAY. STRONG SFC HIGH PRESSURE CENTERED JUST SOUTH OF OUR AREA INTO WISCONSIN HAS RESULTED IN VERY COLD TEMPS (5 TO 15 BELOW ZERO) EARLY THIS MORNING...ESPECIALLY ACROSS THE WESTERN INTERIOR OF UPPER MICHIGAN. NOT MUCH WIND ACCOMPANYING THESE COLD TEMPS SO WENT AHEAD AND CANCELLED THE WIND CHILL ADVISORY FOR THE WESTERN INTERIOR CWA. WIND PARALLEL LES BANDS STILL IMPACTING THE KEWEENAW PENINSULA AND ERN SHORELINE AREAS EARLY THIS MORNING IN CONVERGENT LOW-LVL WESTERLY FLOW. WOULD NOT BE SURPRISED IF THESE AREAS ESPECIALLY THE KEWEENAW RECEIVED AN ADDITIONAL 3 TO 5 INCHES OF LES OVERNIGHT. TODAY...ANY REMAINING LES IS EXPECTED TO LIFT NORTH OF THE KEWEENAW AND THE SHORELINES OF THE ERN COUNTIES AS WINDS BEGIN TO BACK SW IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 275K-285K ISENTROPIC LIFT AHEAD OF SHORTWAVE LIFTING OUT OF THE WRN CONUS TROF WILL SPREAD LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH BY EARLY AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z WILL BE RELATIVELY LIGHT...GENERALLY A HALF INCH OR LESS MOST AREAS WITH MAYBE UP TO AN INCH SOUTH CENTRAL ALONG LAKE MI CLOSER TO BEST ISENTROPIC LIFT AND Q-VECT CONV. TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT TOWARD THE GREAT LAKES FORCING IN LEFT EXIT REGION OF UPPER JET AND ASSOC 700-600 MB FGEN RESPONSE ALONG WITH NOTED MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV OFF CROSS SECTIONS COULD RESULT IN HEAVIER BANDED SNOW OVER SE COUNTIES. ENHANCEMENT TO SYSTEM SNOW IS ALSO POSSIBLE NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE SHIFTING SOUTH THROUGH THE NIGHT /E WINDS IN LOW-LEVELS WITH 8H TEMPS AROUND -12C AND LK MICHIGAN WATER TEMPS AROUND +5C. BIGGEST LIMITING FACTOR FOR LAKE ENHANCED SNOW WILL BE SHIFTING WIND DIRECTION. EXPECT GENERAL 1-3" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S AROUND 18:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEM UNLIKELY DUE TO BEST LIFT OCCURING ABV DGZ. COULD SEE ANOTHER 1-2 OF LAKE ENHANCEMENT ON TOP OF SYSTEM SNOW PUSHING TOTAL SNOW AMOUNTS INTO LOW END ADVISORY CATEGORY WITH 4-5 INCHES. AS A RESULT...WILL CONTINUE THE WINTER WX ADVISORY FOR SE AND ERN COUNTIES TONIGHT INTO EARLY MONDAY. FARTHER WEST GENERALLY EXPECT NO MORE THAN 1-2 INCHES OF TOTAL SNOWFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 601 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...STRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 601 AM EST SUN DEC 8 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS THE EAST HALF OF LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE WESTERLY WINDS OF UP TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...ROLFSON MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 526 AM EST SUN DEC 8 2013 PERSISTENT DEEP TROUGHING OVER THE EASTERN HALF OF CANADA WILL BRING REINFORCING SHOTS OF ARCTIC AIR THROUGH THE WEEK AHEAD. LAKE EFFECT SNOW WILL ONCE AGAIN AFFECT LOCATIONS THAT SAW PLENTY THE LAST FEW DAYS AS W TO WNW FLOW REMAINS FAIRLY CONTINUOUS. A WEAK CLIPPER SYSTEM LOOKS TO BE THE ONLY REAL SHOT OF VERY LIGHT SYNOPTIC SNOWFALL FOR THE ENTIRE CWA LATE MONDAY NIGHT INTO TUESDAY MORNING. MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY MORNING. SEE THE SHORT TERM DISCUSSION FOR DETAILS REGARDING THE MAIN PORTION OF THIS SYSTEM TONIGHT. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. H8 TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 7KFT AND UNIDIRECTIONAL WESTERLY WINDS SHOULD RESULT IN A FAIRLY PERSISTENT DOMINATE LAKE EFFECT SNOW BAND AFFECTING NORTHERN HOUGHTON AND SOUTHERN KEWEENAW COUNTIES. BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL MAKE CONDITIONS POOR...BUT IF THE BAND REMAINS ANCHORED IN ONE AREA FOR AT LEAST SEVERAL HOURS...WARNING CRITERIA SNOW WILL BE POSSIBLE. BECAUSE OF THIS POTENTIAL ALONG WITH POSSIBLE NEAR BLIZZARD CONDITIONS AT TIMES...HAVE ISSUED A LAKE EFFECT SNOW WATCH FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES MONDAY MORNING INTO MONDAY EVENING. GUSTY WINDS WILL LIKELY CONTINUE WELL INTO THE NIGHT...SO BLOWING SNOW WILL REMAIN A PROBLEM. OVERALL...EXPECTATION IS THAT SOME LOCATIONS COULD SEE IN EXCESS OF A FOOT OF SNOW MONDAY MORNING THROUGH EVENING...WITH EVEN HIGHER AMOUNTS IF THE BAND REMAINS IN PLACE. THROUGH...WITH A SLIGHT VEERING OF THE ABOVE-SFC WINDS AHEAD OF A WEAK MID-LEVEL RIDGE LATE MONDAY AFTERNOON...THE BAND WILL LIKELY WAVER SOMEWHAT. MONDAY NIGHT AND TUESDAY...SUFFICIENT MODEL AGREEMENT AND RUN-TO-RUN CONTINUITY THROUGH THIS PERIOD LEADS TO HIGHER CONFIDENCE IN THE GOING FORECAST. DID NOT CHANGE MUCH FROM THE PREVIOUS SHIFT OTHER THAN MAKE SOME MINOR ADJUSTMENTS TO POPS AND QPF. THE SECOND OF MULTIPLE WAVES ON THE DEEP TROUGH IS PROGGED TO CROSS UPPER MI LATE MONDAY NIGHT. LITTLE ADDITIONAL SYNOPTIC SUPPORT WILL BE PRESENT WITH THIS TROUGH...SO ONLY A DUSTING OF SNOW IS EXPECTED FOR MOST LOCATIONS IN THE CWA TUESDAY MORNING. THE APPROACH OF THE TROUGH SHOULD BE ENOUGH TO LIMIT LES OFF ON THE KEWEENAW FOR AT LEAST A SHORT TIME FRAME TUESDAY. ALSO OF NOTE...LOW TEMPS MONDAY NIGHT HAVE A HIGH COMPONENT OF VARIABILITY WITH THEM AS A WEAK SFC RIDGE CROSSES THE CWA WHILE HIGH CLOUDS AHEAD OF TUESDAYS SYSTEM FILTER INTO THE AREA. WENT WITH COLDEST TEMPS TO AROUND -10F INTERIOR CENTRAL AS THAT AREA LOOKS TO HAVE THE LONGEST PERIOD OF UNINTERRUPTED COOLING. TUESDAY NIGHT THROUGH THURSDAY...YET ANOTHER BLAST OF ARCTIC AIR ARRIVES BEHIND TUESDAYS SYSTEM...THIS TIME WITH H8 TEMPS PUSHING -25C BY WEDNESDAY AFTERNOON. COULD SEE SOME LOCATIONS WEST ALONG THE WI BORDER FAIL TO GET ABOVE ZERO ON WEDNESDAY. VERY COLD TEMPS ARE EXPECTED THROUGH THURSDAY...WITH WIND CHILL READINGS TO -30F WEDNESDAY NIGHT INTERIOR WEST. WINDS MAY REMAIN LIGHT...SO WIND CHILL HEADLINES MAY NOT BE NECESSARY. LAKE EFFECT SNOW WILL ONCE AGAIN BE A CONCERN THROUGH THIS STRETCH...ONLY THIS TIME WITH A LITTLE MORE OF A NORTHERLY COMPONENT TO THE WIND. THIS WILL BRING THE POTENTIAL FOR HEAVY LES TUESDAY NIGHT THROUGH THURSDAY NIGHT FOR THE KEWEENAW AND LOCATIONS EAST OF MUNISING ALONG LAKE SUPERIOR. THE SETUP LOOKS FAIRLY SIMILAR TO THE PAST SEVERAL DAYS...SO WOULD NOT BE SURPRISED TO SEE A DOMINATE BAND AFFECTING BOTH OF THE AFOREMENTIONED LOCATIONS. FRIDAY AND SATURDAY...MODEL GUIDANCE DIVERGES QUICKLY AT THIS POINT...WITH THE ECMWF PULLING DOWN ONE MORE ARCTIC AIR MASS WHILE THE GFS TRENDS TO A MORE ZONAL PATTERN. EITHER WAY...A BRIEF ROUND OF LIGHT SYNOPTIC SNOW LOOKS POSSIBLE THURSDAY NIGHT INTO FRIDAY. CONTINUED TO EMPLOY A CONSENSUS FORECAST AT THIS POINT. TEMPERATURES WILL MODERATE SOMEWHAT BY NEXT WEEKEND...BUT STILL REMAIN 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...STRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR MIZ001-003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. GALE WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1243 AM EST SUN DEC 8 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 DEEP TROUGHING ORIENTED FROM EASTERN CANADA ACROSS THE GREAT LAKES AND WEST TO THE SOUTHWEST CONUS IS REINFORCED THROUGHOUT THE UPCOMING WEEK. COLD AIRMASS MAY FINALLY MAY START TO RELAX BY NEXT WEEKEND AS FLOW ALOFT BECOMES MORE ZONAL. FLOW PATTERN THIS WEEK REMAINS ACTIVE ACROSS THE UPPER LAKES. A COUPLE OF SYSTEMS WILL CROSS THE AREA WITH WIDESPREAD SYSTEM SNOWS. MOST SIGNIFICANT OF THESE WILL OCCUR SUNDAY NIGHT AS SHORTWAVE/PV ANAMOLY CROSSING NEVADA/UTAH THIS AFTN/EVENING HEADS OUT INTO CNTRL PLAINS SUNDAY AFTN THEN LIFTS ACROSS UPPER GREAT LAKES SUNDAY NIGHT. SLIGHT WARM AIR ADVECTION...RELATIVE TERM IN THIS AIRMASS...OCCURS OVER SOUTH CENTRAL AND EASTERN CWA SUNDAY EVENING WITH PVA/DEEP LAYER FORCING THROUGH REST OF NIGHT. CROSS-SECTIONS INDICATE VERY SHALLOW FGEN FORCING BLO H9...MAINLY SOUTH AND EAST. MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV TO RESULT IN HEAVIER BANDED SNOW THOUGH. ENHANCEMENT TO SYSTEM SNOW MAY OCCUR NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE/E WINDS IN LOW-LEVELS WITH TEMPS AT INVERSION TOP OF H85 AROUND -10C /LK MICHIGAN WATER TEMPS ARE AROUND +5C/. TRICK IS HOW LONG FAVORABLE WIND DIRECTION PERSISTS AND WHETHER THERE IS TOO MUCH SHEAR IN LAKE CONVECTIVE LAYER TO OFFSET THIS. EXPECT GENERAL 2-4" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S 17-19:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEMED TOUGHER TO ACHIEVE AS BULK OF LIFT WILL BE OCCURRING AT TEMPS LESS THAN -20C. SLR/S WILL PROBABLY BE EVEN LOWER HEADING FARTHER NORTH INTO UPR MICHIGAN...SO SNOW AMOUNTS OF AN INCH MAYBE TWO ARE EXPECTED CLOSER TO LK SUPERIOR SHORE. ISSUED WINTER WEATHER ADVY FOR THE SYSTEM SNOW. BASED ON SREF PLUMES AND FCST POPS...VALID TIME OF ADVY FAR SCNTRL WILL START LATE SUNDAY AFTN AND GO THROUGH DAYBREAK ON MONDAY. ADVY FOR ZONES TO THE EAST WILL START AND END A FEW HOURS LATER. LOW PRESSURE SYSTEM LIFTS TO NORTHEAST OF LK SUPERIOR BY 18Z ON MONDAY AND THIS WILL USHER IN ANOTHER RETURN TO THE COLD AND WINDY WEATHER THAT OCCURRED LATE THIS LAST WEEK INTO TODAY. AND YES...LAKE EFFECT SNOWS...HEAVY AT TIMES...WILL RAMP UP AGAIN IN THE AREAS FAVORED BY WNW-W FLOW. SO...ONCE AGAIN...KEWEEENAW PENINSULA WILL BE IN LINE FOR HEAVY LK EFFECT SNOWS. SOUNDINGS IN WAKE OF THE LOW PRESSURE INDICATE MOIST/UNSTABLE PROFILE TO H7 WITH SHARP CONVERGENCE DEVELOPING ACROSS KEWEENAW BY MID MORNING MONDAY AND CONTINUING THROUGH AT LEAST LATE EVENING ON MONDAY NIGHT. SIMILAR TO THURSDAY...IF WESTERLY FLOW CAN PERSIST IN ONE AREA...LEADING TO STRONG CONVERGENCE...FOOT PLUS AMOUNTS WILL BE POSSIBLE ACROSS CNTRL HOUGHTON COUNTY... AFFECTING PAINESDALE...ATLANTIC MINE...HOUGHTON AND HANCOCK AND POSSIBLY AS FAR NORTH AS CALUMET AND MOHAWK. LAKE EFFECT HEADLINES ARE RUNNING THEIR COURSE CURRENTLY...SO DID NOT WANT TO PUT UP ANOTHER LK EFFECT SNOW WATCH AT THIS TIME. WILL LET MID SHIFT ASSESS THIS POTENTIAL. MAIN ISSUE AWAY FM THE INCREASING LK EFFECT BY MONDAY AFTN WILL BE ANOTHER BLAST OF COLD TEMPS AND LOWERING WIND CHILL READINGS. DOES APPEAR THAT AS STRONGER SHORTWAVE/PRETTY DECENT AREA OF H7-H5 Q-VECTOR CONVERGENCE ARRIVES LATER MONDAY NIGHT...BLYR WINDS BACK SW ENOUGH TO DISRUPT HEAVIER SNOW ON THE KEWEENAW. THIS MAY PROVIDE A GOOD BREAK POINT FOR WHATEVER HEADLINE IS ISSUED FOR MONDAY AND MONDAY EVENING...THOUGH THERE IS A CHANCE THE HEAVIER SNOW BANDS WILL JUST MAKE INTO KEWEENAW COUNTY BEFORE STALLING OUT. TOUGH TO SAY AT THIS POINT. SOUNDINGS ELSEHWERE INDICATE ENOUGH MOISTENING AND LIFT TO INCREASE POPS FOR THE SYSTEM...ESPECIALLY NORTH HALF. SNOW AMOUNTS FM THE SYSTEM WILL BE ON THE LGT SIDE...LESS THAN AN INCH MAINLY. OTHER IMPACT FM THE SHORTWAVE WILL BE FOR TEMPS TO TRY TO RISE SOME LATER MONDAY NIGHT AS THE WINDS INCREASE. THIS MAKES FOR TRICKY WIND CHILL FORECAST. CURRENT FCST FOR WINDS AND TEMPS DOES SUGGEST THAT WESTERN HALF OF CWA MAY SEE WIND CHILL CRITERIA BE MET AT TIMES ON MONDAY NIGHT INTO TUESDAY MORNING. LAST IMPACT FROM THE SYSTEM WILL BE TO PUSH STRONGER SFC TROUGH SOUTH ACROSS LK SUPERIOR RESULTING IN MORE OF A NW WIND IN BLYR FOR TUESDAY/TUESDAY NIGHT. USED LK EFFECT CLIMATOLOGY POPS TO BRING HIGHER POPS TO AREAS FAVORED BY WNW FLOW SUCH AS ONTONAGON COUTNY AND ALSO IN THE EASTERN CWA...MAINLY EAST OF MUNISING AND TO THE NORTH OF NEWBERRY. IN WAKE OF THE TROUGH PASSAGE...COLDEST AIR OF WEEK POURS ACROSS WITH H85 TEMPS DOWN TO AROUND -25C TUESDAY NIGHT INTO WEDNESDAY. MAY HAVE MORE WIND CHILL ISSUES TUESDAY NIGHT INTO WEDNESDAY AS INLAND TEMPS FALL BLO ZERO AND WINDS STAY UP BEHIND THE TROUGH. COLDEST DAY OF THE WEEK FOR WEDNESDAY WITH MAX TEMPS OVER INLAND WEST POSSIBLY STAYING AT OR BLO ZERO THE ENTIRE DAY. COLDEST NIGHT OF THE WEEK LIKELY ON WEDNESDAY NIGHT. AS WINDS GO CALM MAY SEE MINS LESS THAN 20 BLO ZERO. SLIGHT WARMING TREND FOR LATE THIS WEEK...BUT STILL QUITE A BIT BLO NORMAL FOR DAYTIME HIGHS. WEST/SOUTHWEST FLOW LK EFFECT STAYS IN PLACE ON KEWEENAW THURSDAY BUT THEN SHOULD REORIENT TO MORE NNW-N FLOW AREAS ON FRIDAY AS ANOTHER SFC TROUGH SWINGS ACROSS. MAY SEE SOME SYSTEM SNOW THURSDAY NIGHT INTO FRIDAY AHEAD OF THAT TROUGH BUT THERE ARE SOME TIMING ISSUES THERE STILL...SO WILL JUST HAVE LOW CHANCE POPS FOR NOW. DID BUMP UP THE CONSENSUS POPS FOR THE LK EFFECT AREAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1239 AM EST SUN DEC 8 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...STRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR MIZ002-004-009>011-084. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR MIZ003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST SAT DEC 7 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS DIGGING FROM NRN CA INTO NEVADA. AT THE SFC...WRLY WINDS PREVAILED THROUGH THE UPPER GREAT LAKES TO THE NORTH OF THE ARCTIC RIDGE BUILDING FROM THE NRN PLAINS AND UPPER MS VALLEY TO THE SRN LAKES. VERY COLD AIR REMAINED WITH MID AFTERNOON READINGS ONLY CLIMBING INTO THE 5F TO 15F RANGE THROUGH MID AFTERNOON. VIS SATELLITE INDICATED BACKING WINDS OVER WRN LAKE SUPERIOR WITH THE LES BANDS BECOMING ALIGNED FROM SW-NE. TONIGHT...EXPECT LES BANDS INTO THE KEWEENAW TO LIFT SLOWLY NORTHWARD THIS EVENING. EVEN THOUGH THE HIGHER RES MODELS INDICATED PERSISTENT LOW LEVEL CONV AND LES FROM AT LEAST CMX NORTHWARD...CONFIDENCE IS LOWER GIVEN THE SATELLITE TRENDS. SO...THE ONGOING HEADLINES WERE RETAINED FOR NOW BUT MAY NEED TO BE LIFTED EARLIER THAN PREVIOUSLY FCST. IF A DOMINANT BAND CAN REDEVELOP AND BRUSH THE WRN SHORE OF THE KEWEENAW...ADDITIONAL SNOWFALL AMOUNTS OF 3 TO 6 INCHES MAY BE POSSIBLE. WITH A PERIOD OF FAVORABLE RADIATIONAL COOLING UNTIL LATE TONIGHT... EXPECT MIN TEMPS NEAR LOWER END OF GUIDANCE WITH LOW TO MID TEENS BELOW ZERO ACROSS MUCH OF THE WRN INTERIOR RANGING TO AROUND ZERO OVER THE INTERIOR EAST. WINDS INTO THE 5 T0 10 MPH RANGE TIL LATE TONIGHT CAUSED WIND CHILL READINGS TO DIP TO NEAR 25 BELOW...SO THE WIND CHILL ADVISORY WAS RETAINED. THE POTENTIAL FOR INCREASING HIGH CLOUDS LATE TONIGHT COULD CAUSE TEMPS TO LEVEL OFF A BIT OR RISE SLIGHTLY TOWARD 12Z SUN. SUN...ANY REMAINING LES IS EXPECTED TO LIFT TO THE NORTH OF KEWEENAW AS WINDS BACK IN THE DEVELOPING WAA PATTERN. A BROAD AREA OF 280K-290K ISENTROPIC LIFT WILL BRING LIGHT SNOW FROM MN/WI INTO UPPER MI DURING THE AFTERNOON. ALTHOUGH...THE VERY DRY LOW LEVELS IN THE ARCTIC AIRMASS MAY DELAY THE ONSET OF THE PCPN...EXPECT AT LEAST SOME LIGHT SNOW OVER THE SOUTH IN THE AFTERNOON THAT WILL SPREAD THROUGH THE REST OF THE CWA BY MID TO LATE AFTERNOON. ACCUMULATIONS BY 00Z/09 WILL BE RELATIVELY LIGHT...AROUND A HALF INCH OR LESS...MAINLY OVER THE SOUTH. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 416 PM EST SAT DEC 7 2013 DEEP TROUGHING ORIENTED FROM EASTERN CANADA ACROSS THE GREAT LAKES AND WEST TO THE SOUTHWEST CONUS IS REINFORCED THROUGHOUT THE UPCOMING WEEK. COLD AIRMASS MAY FINALLY MAY START TO RELAX BY NEXT WEEKEND AS FLOW ALOFT BECOMES MORE ZONAL. FLOW PATTERN THIS WEEK REMAINS ACTIVE ACROSS THE UPPER LAKES. A COUPLE OF SYSTEMS WILL CROSS THE AREA WITH WIDESPREAD SYSTEM SNOWS. MOST SIGNIFICANT OF THESE WILL OCCUR SUNDAY NIGHT AS SHORTWAVE/PV ANAMOLY CROSSING NEVADA/UTAH THIS AFTN/EVENING HEADS OUT INTO CNTRL PLAINS SUNDAY AFTN THEN LIFTS ACROSS UPPER GREAT LAKES SUNDAY NIGHT. SLIGHT WARM AIR ADVECTION...RELATIVE TERM IN THIS AIRMASS...OCCURS OVER SOUTH CENTRAL AND EASTERN CWA SUNDAY EVENING WITH PVA/DEEP LAYER FORCING THROUGH REST OF NIGHT. CROSS-SECTIONS INDICATE VERY SHALLOW FGEN FORCING BLO H9...MAINLY SOUTH AND EAST. MINIMAL SLANTWISE INSTABILITY/NEGATIVE EPV TO RESULT IN HEAVIER BANDED SNOW THOUGH. ENHANCEMENT TO SYSTEM SNOW MAY OCCUR NEAR BAY OF GREEN BAY AND LK MICHIGAN WITH ESE/E WINDS IN LOW-LEVELS WITH TEMPS AT INVERSION TOP OF H85 AROUND -10C /LK MICHIGAN WATER TEMPS ARE AROUND +5C/. TRICK IS HOW LONG FAVORABLE WIND DIRECTION PERSISTS AND WHETHER THERE IS TOO MUCH SHEAR IN LAKE CONVECTIVE LAYER TO OFFSET THIS. EXPECT GENERAL 2-4" OF SYNOPTIC SNOW WITH MIXING RATIOS 1-2G/KG AND WITH 0.15-0.20 AVERAGED MODEL QPF USING SLR/S 17-19:1. BASED ON SOUNDINGS...HIGHER SLR/S SEEMED TOUGHER TO ACHIEVE AS BULK OF LIFT WILL BE OCCURRING AT TEMPS LESS THAN -20C. SLR/S WILL PROBABLY BE EVEN LOWER HEADING FARTHER NORTH INTO UPR MICHIGAN...SO SNOW AMOUNTS OF AN INCH MAYBE TWO ARE EXPECTED CLOSER TO LK SUPERIOR SHORE. ISSUED WINTER WEATHER ADVY FOR THE SYSTEM SNOW. BASED ON SREF PLUMES AND FCST POPS...VALID TIME OF ADVY FAR SCNTRL WILL START LATE SUNDAY AFTN AND GO THROUGH DAYBREAK ON MONDAY. ADVY FOR ZONES TO THE EAST WILL START AND END A FEW HOURS LATER. LOW PRESSURE SYSTEM LIFTS TO NORTHEAST OF LK SUPERIOR BY 18Z ON MONDAY AND THIS WILL USHER IN ANOTHER RETURN TO THE COLD AND WINDY WEATHER THAT OCCURRED LATE THIS LAST WEEK INTO TODAY. AND YES...LAKE EFFECT SNOWS...HEAVY AT TIMES...WILL RAMP UP AGAIN IN THE AREAS FAVORED BY WNW-W FLOW. SO...ONCE AGAIN...KEWEEENAW PENINSULA WILL BE IN LINE FOR HEAVY LK EFFECT SNOWS. SOUNDINGS IN WAKE OF THE LOW PRESSURE INDICATE MOIST/UNSTABLE PROFILE TO H7 WITH SHARP CONVERGENCE DEVELOPING ACROSS KEWEENAW BY MID MORNING MONDAY AND CONTINUING THROUGH AT LEAST LATE EVENING ON MONDAY NIGHT. SIMILAR TO THURSDAY...IF WESTERLY FLOW CAN PERSIST IN ONE AREA...LEADING TO STRONG CONVERGENCE...FOOT PLUS AMOUNTS WILL BE POSSIBLE ACROSS CNTRL HOUGHTON COUNTY... AFFECTING PAINESDALE...ATLANTIC MINE...HOUGHTON AND HANCOCK AND POSSIBLY AS FAR NORTH AS CALUMET AND MOHAWK. LAKE EFFECT HEADLINES ARE RUNNING THEIR COURSE CURRENTLY...SO DID NOT WANT TO PUT UP ANOTHER LK EFFECT SNOW WATCH AT THIS TIME. WILL LET MID SHIFT ASSESS THIS POTENTIAL. MAIN ISSUE AWAY FM THE INCREASING LK EFFECT BY MONDAY AFTN WILL BE ANOTHER BLAST OF COLD TEMPS AND LOWERING WIND CHILL READINGS. DOES APPEAR THAT AS STRONGER SHORTWAVE/PRETTY DECENT AREA OF H7-H5 Q-VECTOR CONVERGENCE ARRIVES LATER MONDAY NIGHT...BLYR WINDS BACK SW ENOUGH TO DISRUPT HEAVIER SNOW ON THE KEWEENAW. THIS MAY PROVIDE A GOOD BREAK POINT FOR WHATEVER HEADLINE IS ISSUED FOR MONDAY AND MONDAY EVENING...THOUGH THERE IS A CHANCE THE HEAVIER SNOW BANDS WILL JUST MAKE INTO KEWEENAW COUNTY BEFORE STALLING OUT. TOUGH TO SAY AT THIS POINT. SOUNDINGS ELSEHWERE INDICATE ENOUGH MOISTENING AND LIFT TO INCREASE POPS FOR THE SYSTEM...ESPECIALLY NORTH HALF. SNOW AMOUNTS FM THE SYSTEM WILL BE ON THE LGT SIDE...LESS THAN AN INCH MAINLY. OTHER IMPACT FM THE SHORTWAVE WILL BE FOR TEMPS TO TRY TO RISE SOME LATER MONDAY NIGHT AS THE WINDS INCREASE. THIS MAKES FOR TRICKY WIND CHILL FORECAST. CURRENT FCST FOR WINDS AND TEMPS DOES SUGGEST THAT WESTERN HALF OF CWA MAY SEE WIND CHILL CRITERIA BE MET AT TIMES ON MONDAY NIGHT INTO TUESDAY MORNING. LAST IMPACT FROM THE SYSTEM WILL BE TO PUSH STRONGER SFC TROUGH SOUTH ACROSS LK SUPERIOR RESULTING IN MORE OF A NW WIND IN BLYR FOR TUESDAY/TUESDAY NIGHT. USED LK EFFECT CLIMATOLOGY POPS TO BRING HIGHER POPS TO AREAS FAVORED BY WNW FLOW SUCH AS ONTONAGON COUTNY AND ALSO IN THE EASTERN CWA...MAINLY EAST OF MUNISING AND TO THE NORTH OF NEWBERRY. IN WAKE OF THE TROUGH PASSAGE...COLDEST AIR OF WEEK POURS ACROSS WITH H85 TEMPS DOWN TO AROUND -25C TUESDAY NIGHT INTO WEDNESDAY. MAY HAVE MORE WIND CHILL ISSUES TUESDAY NIGHT INTO WEDNESDAY AS INLAND TEMPS FALL BLO ZERO AND WINDS STAY UP BEHIND THE TROUGH. COLDEST DAY OF THE WEEK FOR WEDNESDAY WITH MAX TEMPS OVER INLAND WEST POSSIBLY STAYING AT OR BLO ZERO THE ENTIRE DAY. COLDEST NIGHT OF THE WEEK LIKELY ON WEDNESDAY NIGHT. AS WINDS GO CALM MAY SEE MINS LESS THAN 20 BLO ZERO. SLIGHT WARMING TREND FOR LATE THIS WEEK...BUT STILL QUITE A BIT BLO NORMAL FOR DAYTIME HIGHS. WEST/SOUTHWEST FLOW LK EFFECT STAYS IN PLACE ON KEWEENAW THURSDAY BUT THEN SHOULD REORIENT TO MORE NNW-N FLOW AREAS ON FRIDAY AS ANOTHER SFC TROUGH SWINGS ACROSS. MAY SEE SOME SYSTEM SNOW THURSDAY NIGHT INTO FRIDAY AHEAD OF THAT TROUGH BUT THERE ARE SOME TIMING ISSUES THERE STILL...SO WILL JUST HAVE LOW CHANCE POPS FOR NOW. DID BUMP UP THE CONSENSUS POPS FOR THE LK EFFECT AREAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1156 PM EST SAT DEC 7 2013 WITH A DRY ARCTIC AIR MASS OVER THE AREA...AN OFFSHORE WIND DIRECTION AT KSAW WILL RESULT IN VFR CONDITIONS THRU THE MORNING HRS. AT KIWD...WINDS HAVE VEERED JUST ENOUGH OFF THE DECK TO BRING LAKE STRATOCU (MVFR CIGS) INTO THE AREA. AS WINDS BACK AGAIN OVER THE NEXT FEW HRS...SRATOCU WILL CLEAR OUT WITH VFR CONDITIONS THEN CONTINUING THRU THE MORNING. AT KCMX...LAKE EFFECT SNOW WILL CONTINUE THRU THE EARLY MORNING AS WINDS WILL HAVE ENOUGH OF AN ONSHORE COMPONENT. EXPECT CONDITIONS TO VARY GENERALLY BTWN IFR AND MVFR THRU THE NIGHT THOUGH BRIEF LIFR POSSIBLE OVER THE NEXT COUPLE OF HRS. WITH LOSS OF ONSHORE WIND COMPONENT TOWARD DAYBREAK AS WINDS BACK...CONDITIONS WILL IMPROVE TO VFR. IN THE AFTN...NEXT DISTURBANCE WILL APPROACH FROM THE SW. EXPECT -SN/MVFR CONDITIONS TO SPREAD NE TO ALL TERMINALS DURING THE AFTN...BEGINNING FIRST AT KIWD. WITH KSAW CLOSER TO THE TRACK OF THE DISTURBANCE...IFR CONDITIONS ARE MORE LIKELY TO DEVELOP THERE IN THE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 PM EST SAT DEC 7 2013 EXPECT BRIEF BREAK IN STRONGER WINDS OVER LK SUPERIOR LATER THIS EVENING THROUGH SUNDAY AS PRESSURE GRADIENT WEAKENS. A LOW PRESSURE SYSTEM MOVING ACROSS THE AREA ON SUNDAY NIGHT...BUT WINDS WILL REMAIN LESS THAN 25 KTS. AS THE LOW MOVES OUT OF THE AREA ON MONDAY...EXPECT THE GRADIENT TO TIGHTEN AND WEST GALES TO DEVELOP THROUGH MONDAY NIGHT. ANOTHER LOW PRESSURE SYSTEM WILL PASS THROUGH THE UPPER GREAT LAKES TUESDAY INTO WEDNESDAY...POSSIBLY LEADING TO MORE GALES FROM THE WEST TO NORTHWEST TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002- 004-009>011-084. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST SUNDAY FOR MIZ003. WINTER WEATHER ADVISORY FROM 4 PM EST /3 PM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR MIZ012-013. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST SUNDAY FOR MIZ001. WINTER WEATHER ADVISORY FROM 7 PM SUNDAY TO 9 AM EST MONDAY FOR MIZ007-014-085. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR LSZ264>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 PM CST Sat Dec 7 2013 .UPDATE: Issued at 944 PM CST Sat Dec 7 2013 Several narrow snow bands have developed this evening across southwest Missouri in an area of strong mid level frontogenetical forcing and low/mid level warm advection ahead of a short wave moving through the southern plains. Snow is reaching the ground in and there are areas that have a dusting. The latest RAP and HRRR runs increase the forcing and shift it northeastward parallelling I-44 during the overnight hours and into the St. Louis metro area. This seems reasonable based on observed trends. The only question is the coverage and whether a wider more solitary band will evolve or whether it will remain with several narrow bands. At this time I have increased the pops within this corridor but only mentioned scattered snow showers due to the uncertainty in the coverage evolution. Some areas could certainly pick up a dusting to half inch beneath them. If the coverage expands I will probably need to boost pops into the likely category before the evening is over. Glass && .SHORT TERM: (Through Sunday Evening) Issued at 301 PM CST Sat Dec 7 2013 Strong shortwave dipping into the base of the upper level trof across the western CONUS will move across the Four Corners tonight and emerge into the Plains on Sunday morning. Impressive warm advection forecast to develop ahead of the shortwave with light qpf noted on all model guidance to march northeast across the CWA from late tonight through Sunday afternoon. Believe this is one of those high PoP/low QPF events. Precipitation type is not clear cut...as lack of ice crystal formation is noted on model soundings. I also note that there is a steady stream of mid and high level clouds streaming northeast from Texas. Wonder if the ice crystals from the higher clouds will lead to a seeder/feeder situation, ultimately allowing the precipitation to fall as more snow or snow grains rather than freezing drizzle late tonight and tomorrow morning. Tomorrow afternoon the best lift will be moving northeast and the lower atmosphere will be warming so precipitation will likely turn to areas of freezing drizzle that may continue into the evening. Overall believe snowfall amounts will remain under an inch and any freezing drizzle will only produce a light glaze. Will let the evening and overnight shifts take a look at the 00Z model data to determine the need, if any, for headlines on Sunday. CVKING .LONG TERM: (Sunday Night through Next Saturday) Issued at 301 PM CST Sat Dec 7 2013 Cold front will progress southeast across the CWA late Sunday night, reinforcing the cold for the beginning of the work week. Next shortwave moves into the Plains Monday night an CWA will be in a favorable area of synoptic lift provided by the right entrance region of the jet streak to our northeast. This may ultimately provide another chance of light snow south of Interstate 70. Have kept slight chance PoPs at this time. Extended forecast remains dry and cold with cold front passages Wednesday and Friday. CVKING && .AVIATION: (For the 06z TAFs through 06z Sunday Night) Issued at 1139 PM CST Sat Dec 7 2013 Have added mention of SN early in the period for STL/SUS/CPS for approaching band of SN. This initial band is expected to be short lived as it moves nwd thru the area. Also added light SN at COU/UIN just before sunrise, but there is some uncertainty how intense the SN will be. After a lull in precip, prev TAF forecast still appears on track with another round mid to late morning and gradually changing to FZDZ. Same uncertainties exist regarding timing of change over and time when FZDZ will end. Guidance continues to suggest that FZFG may be an issue as precip comes to an end as low clouds settle into the region. For now, have visbys at 5SM, but if trends continue, visbys may need to be lowered. && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
157 PM CST SUN DEC 8 2013 .DISCUSSION... UPDATED TO DROP WINTER WEATHER ADVISORY ACROSS THE AREA. WITH VISILIBITIES NOW AT OR ABOVE 2 SM IN MOST LOCATIONS...ONLY LIGHT ACCUMULATIONS OF A COUPLE TENTHS OF AN INCH ARE EXPECTED. SECONDARY BATCH OF SNOW CURRENTLY IN SOUTHEAST NEB IS PROGGED TO WEAKEN AS IT APPROACHES EASTERN NEB...BUT IT MAY BRING YET ANOTHER TENTH OR TWO OF SNOW. OVERALL...WITH THE ACCUMULATING SNOW DIMINISHING...THE NEED FOR AN ADVISORY HAS DIMINISHED AS WELL. WITH COMPACTION AND SETTLING OF SNOW...MOST LOCATIONS HAVE LIKELY SEEN THEIR PEAK SNOW ACCUMULATIONS. MAYES && .PREV DISCUSSION... /ISSUED 1125 AM CST SUN DEC 8 2013/ AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK. LIGHT TO MODERATE SNOW CONTINUES AT ALL SITES...BUT VIS AND CEILINGS SHOULD GRADUALLY IMPROVE THROUGH THE AFTERNOON. KOMA MAY HOLD ON TO SNOW UNTIL AT LEAST AROUND 00Z...BUT OTHER SITES SHOULD TAPER TO FLURRIES BEFORE THEN. OVERNIGHT...CEILINGS SHOULD DECREASE...WHILE WINDS WILL INCREASE OUT OF THE NORTHWEST. HAVE ONLY BROUGHT WINDS ABOVE 12KT AT KOFK...WITH KOMA/KLNK AT AROUND 10KT...AND WINDS SHOULD BEING TO DECREASE BY AROUND 18Z MONDAY. MAYES PREV DISCUSSION... /ISSUED 854 AM CST SUN DEC 8 2013/ DISCUSSION... HAVE UPDATED THE FORECAST...WITH THE BIGGEST CHANGE BEING THE ADDITION OF PAWNEE AND RICHARDSON COUNTIES TO THE ADVISORY. MODERATE SNOWFALL IS ONGOING THERE...AND THE POTENTIAL IS JUST AS HIGH THERE FOR 2-3 INCHES OF SNOW AS MANY OTHER AREAS OF THE CWA. ACTUALLY REDUCED POPS IN NORTHEAST NEB FOR A SHORT PERIOD THIS LATE MORNING/EARLY AFTERNOON...WHERE THERE ARE LITTLE MORE THAN FLURRIES NOW. ADJUSTED SNOW TOTALS DOWNWARD UP THERE...AND UPWARD IN SOUTHEAST NEB. ALSO UPDATED TEMPERATURE AND DEWPOINT TRENDS...AS TEMPS DID NOT FALL FAR OVERNIGHT AND HAVE BEEN STEADY TO RISING. MAYES PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$ 99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1125 AM CST SUN DEC 8 2013 .AVIATION... 18Z TAFS FOR KOMA...KLNK...AND KOFK. LIGHT TO MODERATE SNOW CONTINUES AT ALL SITES...BUT VIS AND CEILINGS SHOULD GRADUALLY IMPROVE THROUGH THE AFTERNOON. KOMA MAY HOLD ON TO SNOW UNTIL AT LEAST AROUND 00Z...BUT OTHER SITES SHOULD TAPER TO FLURRIES BEFORE THEN. OVERNIGHT...CEILINGS SHOULD DECREASE...WHILE WINDS WILL INCREASE OUT OF THE NORTHWEST. HAVE ONLY BROUGHT WINDS ABOVE 12KT AT KOFK...WITH KOMA/KLNK AT AROUND 10KT...AND WINDS SHOULD BEING TO DECREASE BY AROUND 18Z MONDAY. MAYES && .PREV DISCUSSION... /ISSUED 854 AM CST SUN DEC 8 2013/ DISCUSSION... HAVE UPDATED THE FORECAST...WITH THE BIGGEST CHANGE BEING THE ADDITION OF PAWNEE AND RICHARDSON COUNTIES TO THE ADVISORY. MODERATE SNOWFALL IS ONGOING THERE...AND THE POTENTIAL IS JUST AS HIGH THERE FOR 2-3 INCHES OF SNOW AS MANY OTHER AREAS OF THE CWA. ACTUALLY REDUCED POPS IN NORTHEAST NEB FOR A SHORT PERIOD THIS LATE MORNING/EARLY AFTERNOON...WHERE THERE ARE LITTLE MORE THAN FLURRIES NOW. ADJUSTED SNOW TOTALS DOWNWARD UP THERE...AND UPWARD IN SOUTHEAST NEB. ALSO UPDATED TEMPERATURE AND DEWPOINT TRENDS...AS TEMPS DID NOT FALL FAR OVERNIGHT AND HAVE BEEN STEADY TO RISING. MAYES PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>093. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$ 99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
854 AM CST SUN DEC 8 2013 .DISCUSSION... HAVE UPDATED THE FORECAST...WITH THE BIGGEST CHANGE BEING THE ADDITION OF PAWNEE AND RICHARDSON COUNTIES TO THE ADVISORY. MODERATE SNOWFALL IS ONGOING THERE...AND THE POTENTIAL IS JUST AS HIGH THERE FOR 2-3 INCHES OF SNOW AS MANY OTHER AREAS OF THE CWA. ACTUALLY REDUCED POPS IN NORTHEAST NEB FOR A SHORT PERIOD THIS LATE MORNING/EARLY AFTERNOON...WHERE THERE ARE LITTLE MORE THAN FLURRIES NOW. ADJUSTED SNOW TOTALS DOWNWARD UP THERE...AND UPWARD IN SOUTHEAST NEB. ALSO UPDATED TEMPERATURE AND DEWPOINT TRENDS...AS TEMPS DID NOT FALL FAR OVERNIGHT AND HAVE BEEN STEADY TO RISING. MAYES && .PREV DISCUSSION... /ISSUED 532 AM CST SUN DEC 8 2013/ AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK. LIGHT SNOW WILL CONTINUE OVER THE TAF SITES THROUGH 20Z...WITH THE HEAVIER INTENSITIES REMAINING OVER KLNK. IFR CONDITIONS ARE EXPECTED PRIMARILY AT KLNK IN SNOW WITH MVFR TO VFR AT KOFK AND KOMA. SNOW WILL TAPER OFF AND END FROM WEST TO EAST LATER THIS AFTERNOON. TOTAL SNOWFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE POSSIBLE...WITH THE HEAVIER AMOUNTS AT KLNK AND KOMA. SKIES ARE EXPECTED TO SCATTER OUT THIS EVENING AND EVENTUALLY CLEAR OUT OVERNIGHT. A COLD FRONT WILL MOVE ACROSS THE TAF SITES BY EARLY EVENING. THIS COULD PUSH NORTHWEST WINDS UP TO AROUND 10-12KTS OVERNIGHT AND PRODUCE SOME DRIFTING OF SNOW OVERNIGHT. KERN PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>093. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
532 AM CST SUN DEC 8 2013 .AVIATION...12Z TAFS FOR KOFK...KOMA AND KLNK. LIGHT SNOW WILL CONTINUE OVER THE TAF SITES THROUGH 20Z...WITH THE HEAVIER INTENSITIES REMAINING OVER KLNK. IFR CONDITIONS ARE EXPECTED PRIMARILY AT KLNK IN SNOW WITH MVFR TO VFR AT KOFK AND KOMA. SNOW WILL TAPER OFF AND END FROM WEST TO EAST LATER THIS AFTERNOON. TOTAL SNOWFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE POSSIBLE...WITH THE HEAVIER AMOUNTS AT KLNK AND KOMA. SKIES ARE EXPECTED TO SCATTER OUT THIS EVENING AND EVENTUALLY CLEAR OUT OVERNIGHT. A COLD FRONT WILL MOVE ACROSS THE TAF SITES BY EARLY EVENING. THIS COULD PUSH NORTHWEST WINDS UP TO AROUND 10-12KTS OVERNIGHT AND PRODUCE SOME DRIFTING OF SNOW OVERNIGHT. KERN && .PREV DISCUSSION... /ISSUED 322 AM CST SUN DEC 8 2013/ DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$ 99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
322 AM CST SUN DEC 8 2013 .DISCUSSION... DURATION/COVERAGE/AMOUNTS OF SNOW THROUGH THIS EVENING ARE THE PRIMARY FORECAST CHALLENGES. SNOW DEVELOPED SATURDAY EVENING ACROSS MUCH OF SOUTHERN NEBRASKA INCLUDING SOUTHEAST NEBRASKA...AND HAD SPREAD NORTH TO THE PLATTE RIVER AND THE OMAHA METRO BY MIDNIGHT. THIS WAS SEVERAL HOURS EARLIER THAN MODELS SHOWED 24 HOURS AGO WHEN THEY WERE PAINTING SIGNIFICANT BOUNDARY LAYER DRY AIR THAT WOULD NOT BE OVERCOME UNTIL AFTER MIDNIGHT FOR ALL BUT THE WESTERN CWA. ENHANCED LIFT IN RIGHT ENTRANCE REGION OF UPPER JET OVERCAME THIS DRY AIR RATHER QUICKLY AS RADAR RETURNS BLOSSOMED RAPIDLY SATURDAY EVENING IN SOUTH CENTRAL THEN SOUTHEAST NEBRASKA. 00Z MODELS WERE NOT HANDLING THIS AREA OF PRECIP WELL AT ALL...INSTEAD FOCUSING ON NORTHERN NEBRASKA BY 06Z. HOWEVER MESOSCALE MODELS HRRR AND RAP WERE AT LEAST OFFERING BETTER SOLUTIONS COMPARED TO CURRENT TRENDS. UPPER TROUGH REMAINED WELL TO OUR WEST THIS MORNING...WITH BASE OF TROUGH AXIS NEARING THE FOUR CORNERS REGION AT 08Z. A COUPLE OF SHORTWAVES WERE NOTED IN WATER VAPOR IMAGERY...ONE ROUNDING BASE OF TROUGH THAT WAS SHOWING ENHANCEMENT IN SOUTHERN ARIZONA...AND A SECOND WAS SPINNING THROUGH CENTRAL COLORADO. THE FIRST SHORTWAVE SUGGESTS A STRONG JET SEGMENT THAT WAS NOT HANDLED WELL BY MODELS...AND EXTRAPOLATION PUTS THE LEFT EXIT REGION OF THAT JET INTO NEBRASKA LATER THIS MORNING. THIS WILL AGAIN ENHANCE LIFT IN OUR SOUTHERN/CENTRAL CWA. AND THE COLORADO VORT/SHORTWAVE IS PROGGED TO WORK EAST INTO NEBRASKA THIS AFTERNOON BEFORE EXITING TO OUR EAST BY 06Z. AHEAD OF BOTH SHORTWAVES WE WILL SEE CONTINUED ISENTROPIC UPGLIDE THROUGH THE MORNING AND AFTERNOON BEFORE DOWNGLIDE BEGINS FROM WEST TO EAST LATE IN THE DAY AND EVENING. ISENTROPIC ANALYSIS ALONG THE 285K SURFACE INDICATES MIXING RATIOS OF 2 G/KG WILL CONTINUE TO PUMP INTO OUR SOUTH AND CENTRAL CWA WHERE LIFT IS EXPECTED TO BE STRONGEST. THIS TRANSLATES TO POTENTIALLY ANOTHER 4 INCHES OF SNOW IN THOSE AREAS...PUTTING TOTALS IN THE 3 TO 6 INCH RANGE IN MOST OF THE SOUTHERN HALF OF THE CWA. IN THE NORTHERN HALF AND ESPECIALLY NORTHEAST NEBRASKA...SNOW WAS SLOW TO BEGIN BUT HAS ENHANCED MARKEDLY OVER THE PAST SEVERAL HOURS. REPORTS OF AN INCH OR TWO HAVE COME IN FROM NEAR THE SOUTH DAKOTA BORDER...WITH LESSER AMOUNTS TO THE SOUTH. LIFT IN THAT AREA DOES NOT LOOK AS STRONG AS TO THE SOUTH...BUT AMOUNTS COULD STILL APPROACH 3 INCHES BEFORE ENDING. ALREADY HAVE A WINTER WEATHER ADVISORY GOING FOR MOST OF THE CWA. SOUTHERN AREAS SHOULD EASILY VERIFY THIS...BUT NORTHERN AREAS COULD STRUGGLE TO REACH THE LOWER END OF CRITERIA. HOWEVER WILL MAINTAIN ADVISORY FOR ALL CURRENT AREAS AS SNOW IS JUST GETTING GOING IN OUR NORTH AND EXPECT SOME ENHANCEMENT DURING THE MORNING. SNOW SHOULD BE TAPERING IN OUR WEST BY MID AFTERNOON...THEN EASTERN SECTIONS THIS EVENING. CLEARING SKIES AND FRESH SNOW COVER WILL ALLOW TEMPERATURES TO DROP BELOW ZERO IN MUCH OF THE CWA. NORTHWEST WINDS OF 10 TO 15 MPH SHOULD DEVELOP LATER TONIGHT AND MONDAY MORNING...AND WITH SUB ZERO TEMPERATURES...WIND CHILLS WILL APPROACH 20 BELOW FOR THE START OF THE SCHOOL/WORK WEEK. WILL GO AHEAD AND ISSUE A WIND CHILL ADVISORY FOR A GOOD PART OF OUR NORTHERN CWA FOR LATE TONIGHT AND MONDAY MORNING. ANOTHER SHORTWAVE WILL DIVE INTO THE GREAT LAKES MONDAY NIGHT...CAUSING SURFACE FLOW TO BECOME SOUTHWESTERLY HERE MONDAY AFTERNOON. BUT COLD START AND SNOW WILL KEEP HIGHS ONLY IN THE TEENS. THEN A CLIPPER SYSTEM/SHORTWAVE IS FORECAST THROUGH NORTHEAST NEBRASKA INTO IOWA TUESDAY NIGHT. AGAIN THIS WILL BRING WEST TO SOUTHWEST WINDS TO OUR AREA MONDAY NIGHT AND TUESDAY...KEEPING LOWS ABOVE ZERO AND PUSHING HIGHS INTO THE 20S. MODELS HAVE BEEN PERSISTENT IN DROPPING A STRIPE OF LIGHT SNOW WITH THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING...SO WILL INSERT SMALL CHANCES FOR THIS IN OUR NORTHEAST CWA. MUCH COLDER AIR BEHIND THE CLIPPER WILL KEEP HIGHS IN THE TEENS ON WEDNESDAY. THEN A GRADUAL WARMING TREND LOOKS ON TRACK FOR THURSDAY INTO SATURDAY AS UPPER FLOW TRANSITIONS FROM A NORTHWEST TO ZONAL SETUP. HAVE HIGHS CLOSE TO 30 EACH DAY. DERGAN && .AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. SNOW AT ALL TAF SITES...BUT ENDING BY 09/00Z AT KOFK...01-02Z AT KLNK/KOMA. MVFR CLOUDS MAY EVENTUALLY BECOME IFR BY 10Z AS HEAVIER LIFT MOVES INTO THE REGION...THEN BACK TO MVFR BY 16-18Z. EASTERLY WINDS BECOME SOUTHEAST BUT LESS THAN 12 KNOTS...BUT THEN BECOME LIGHTER AND VARIABLE AS A SURFACE TROUGH APPROACHES BY 19-21Z...THEN NORTHWEST BY 22-24Z. ACCUMULATIONS AT TAF SITES IN THE 3 TO 4 INCHES. DEWALD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011- 012-015>018-030>034-042>045-050>053-065>068-078-088>091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR NEZ011-012- 015>018-030>034-042>045. IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043- 055-056-069-079-080-090-091. WIND CHILL ADVISORY FROM 3 AM TO NOON CST MONDAY FOR IAZ043-055. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
101 PM MST SUN DEC 8 2013 .UPDATE... UPDATED TO CANCEL WIND AND WINTER WEATHER HIGHLIGHTS. FRONTAL BAND HAS WEAKENED SIGNIFICANTLY AS IT MOVED WELL SOUTH OF THE UPPER LEVEL FORCING OVER COLORADO. SFC COLD FRONT IS NOW MAINLY A STALLED WEST TO EAST ORIENTED TEMPERATURE BOUNDARY FROM QUEMADO TO SOCORRO TO CLINES CORNERS TO JUST N/NW OF TUCUMCARI. ISOALTED SNOW SHOWERS WILL CONTINUE OVER THE WESTERN HIGHLANDS AND MTNS AND OVER THE CENTRAL HIGHLANDS THROUGH THE AFTERNOON. THE STALLED SFC FRONT DRAPED FROM WEST TO EAST EXPECTED TO SET THE STAGE FOR MONDAY. 33 && .PREV DISCUSSION...1055 AM MST SUN DEC 8 2013... .AVIATION... 18Z TAF CYCLE LIFR CONDITIONS IN FREEZING FOG AT KROW TO IMPROVE TO VFR BY 20Z THEN REMAIN VFR THROUGH THE TAF PERIOD WITH THE POTENTIAL FOR MVFR CONDITIONS MONDAY MORNING. VFR CONDITIONS FORECAST TO PERSIST AT KFMN...BUT MORE COMPLEX FORECAST FOR KGUP...KABQ...KAEG...KSAF AND KTCC AS ANOTHER SHORTWAVE TROUGH DROPS INTO THE REGION OVERNIGHT THROUGH MONDAY. LIGHT SNOW WITH MVFR CIGS/VSBYS FORECAST TO DEVELOP OVERNIGHT...WITH IFR CONDITIONS POSSIBLE. IMPROVEMENT... IF ANY...MONDAY MORNING WILL BE SLOW AT KGUP...KABQ...KAEG AND KSAF. LIKELY AN ALL-DAY SCENARIO AT KTCC WITH DETERIORATING CONDITIONS. WIND GUSTS TO BETWEEN 35-40KTS AT KLVS AND KTCC THIS AFTERNOON WILL DIMINISH QUICKLY BY EARLY EVENING. 11 .PREV DISCUSSION...338 AM MST SUN DEC 8 2013... ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 33
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1055 AM MST SUN DEC 8 2013 .AVIATION... 18Z TAF CYCLE LIFR CONDITIONS IN FREEZING FOG AT KROW TO IMPROVE TO VFR BY 20Z THEN REMAIN VFR THROUGH THE TAF PERIOD WITH THE POTENTIAL FOR MVFR CONDITIONS MONDAY MORNING. VFR CONDITIONS FORECAST TO PERSIST AT KFMN...BUT MORE COMPLEX FORECAST FOR KGUP...KABQ...KAEG...KSAF AND KTCC AS ANOTHER SHORTWAVE TROUGH DROPS INTO THE REGION OVERNIGHT THROUGH MONDAY. LIGHT SNOW WITH MVFR CIGS/VSBYS FORECAST TO DEVELOP OVERNIGHT...WITH IFR CONDITIONS POSSIBLE. IMPROVEMENT... IF ANY...MONDAY MORNING WILL BE SLOW AT KGUP...KABQ...KAEG AND KSAF. LIKELY AN ALL-DAY SCENARIO AT KTCC WITH DETERIORATING CONDITIONS. WIND GUSTS TO BETWEEN 35-40KTS AT KLVS AND KTCC THIS AFTERNOON WILL DIMINISH QUICKLY BY EARLY EVENING. 11 && .PREV DISCUSSION...338 AM MST SUN DEC 8 2013... ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 5 AM TO 11 PM MST MONDAY FOR THE FOLLOWING ZONES...NMZ518>526-529-531>539. WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ521>524-526>529-533-539-540. WINTER WEATHER ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ501-502-504>506-511-512-515>517. WINTER WEATHER ADVISORY FROM 2 AM TO 4 PM MST MONDAY FOR THE FOLLOWING ZONES...NMZ505>509. WINTER STORM WARNING UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ503-510-513-514. && $$ 33
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
449 AM MST SUN DEC 8 2013 .AVIATION... 12Z TAF CYCLE IFR/LIFR CIGS AND VSBYS IN BR AND FZFG CONTINUE ACROSS THE EASTERN PLAINS THIS MORNING...THOUGH THIS SHOULD CONTINUE TO ERODE FROM WEST TO EAST AS SW WINDS INCREASE THIS MORNING. WILL LIKELY HANG ON THE LONGEST AT KROW. MEANWHILE...SNOW CONTINUES ACROSS THE NORTH AND WEST...WITH THE HEAVIEST SNOW BAND OCCURRING ALONG A COLD FRONT. STRONG AND GUSTY SW TO W WINDS WILL ALSO ARRIVE WITH THE FRONT AND LAST FOR 1 TO 3 HOURS. THOUGH THE BAND OF SNOW WILL STRUGGLE TO MAKE IT EAST OF THE CENTRAL MOUNTAIN CHAIN... THE WIND WILL NOT. GUSTS NEAR 45KT WILL BE POSSIBLE...ESPECIALLY ALONG AND JUST EAST OF THE CENTRAL MTN CHAIN FROM MID MORNING THROUGH EARLY AFTN. WINDS WILL DIMINISH LATE THIS AFTERNOON. MAY SEE SOME LOW CLOUD DEVELOPMENT IN THE VCNTY OF KROW AFT 06Z TONIGHT. 34 && .PREV DISCUSSION...338 AM MST SUN DEC 8 2013... ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ521>524-526>529-533-539-540. WINTER WEATHER ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ501-502-504>506-511-512-515>517. WINTER STORM WARNING UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ503-510-513-514. && $$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
338 AM MST SUN DEC 8 2013 ...STRONGER WINDS AND FRIGID TEMPERATURES TODAY/MONDAY WILL MAKE FOR THE COLDEST DAYS OF THE ARCTIC STRETCH... .DISCUSSION...MID-LEVEL SPEED MAX OF 60-80 KNOTS WITHIN BASE OF A POTENT UPPER LEVEL SHORTWAVE TROUGH TO TRANSLATE EASTWARD OVER THE AREA TODAY. VERY COLD AIR ALOFT CONTRIBUTING TO A BEAUTIFUL SATELLITE PRESENTATION EARLY THIS MORNING. COOLING CLOUD TOPS EVIDENT OVER FAR NW/NC AREAS WHERE CONVECTIVE SNOW BURSTS LIKELY PRODUCING SHORT-DURATION INTENSE SNOW OVER THE HIGHER TERRAIN FROM JUST EAST-NORTHEAST OF FARMINGTON TO CHAMA AND AREAS JUST SOUTH. CHAMA HAD 4 INCHES OF SNOW AS OF MID-EVENING SATURDAY PRIOR TO THESE MORE FAVORABLE CONDITIONS THAT WILL SHIFT TOWARD THE SANGRES. OTHERWISE...TRANSITION TO INCREASINGLY OROGRAPHIC SNOWS EXPECTED AS THE MORNING PROGRESSES WITH BANDED SNOW STRUCTURE EXPECTED ALONG A SURFACE TO MID- LEVEL FRONTAL ZONE THAT WILL CONTINUE TO PRESS EAST- SOUTHEAST AND FAVOR WC AREAS ESPECIALLY NEAR THE DIVIDE. COULD SEE THE REMNANTS OF THIS BAND REACH THE ABQ AREA BY MID- TO LATE MORNING PER THE LATEST HRRR BUT NOT EXPECTING MUCH IMPACT. OF GREATER IMPACT FOR MOST AREAS WILL BE INCREASING WIND AND COMBINED WITH FRIGID TEMPERATURES WILL MAKE IT BRUTAL FOR MUCH OF THE NORTH AND WEST. DOWNSLOPING WINDS FOR THE FIRST TIME IN MANY DAYS SHOULD ACTUALLY HELP IMPROVE CONDITIONS ACROSS THE EASTERN PLAINS WHERE LOW CLOUDS...FREEZING FOG/DRIZZLE WILL CONTINUE THROUGH THE MORNING ACROSS ROUGHLY THE SOUTHEAST QUARTER. BLOWING SNOW IMPACTS COULD BE SIGNIFICANT FOR AREAS THAT RECEIVED HEAVY SNOW THIS PAST THURSDAY AND ARE WELL REMOVED FROM WHERE THE SNOW ACTUALLY FALLS TODAY. ANOTHER VERY INTERESTING/CHALLENGING FORECAST TONIGHT INTO MONDAY. AS THE NEXT REINFORCING AND COLDEST CHUNK OF ARCTIC AIR PLUNGES SOUTH. AND IT WILL DO SO VERY SIMILAR TO HOW THE INITIAL BLAST PLAYED OUT LAST THURSDAY. THAT IS BREAKING DOWN BOTH SIDES OF THE DIVIDE. THERE WILL BE A BACKDOOR SEGMENT THAT WILL PUSH SOUTH AND WEST A LITTLE FASTER THAN THE REINFORCING SURGE OF ARCTIC AIR ACROSS WESTERN NEW MEXICO. AT THE SAME TIME...A POSITIVELY TILTED UPPER TROUGH WILL BE SAGGING SOUTH-SOUTHEAST OVER THE AREA. THE GFS HAS BEEN TARGETING A MESOSCALE BAND OF SNOW AHEAD OF THE UPPER TROUGH AND ALONG THE SOUTHWARD- MOVING ARCTIC REINFORCEMENT MUCH FARTHER WEST AND NORTH COMPARED TO ITS COUNTERPARTS. ECMWF AND ESPECIALLY THE NAM ARE CONSIDERABLY DRIER AND FOCUS MOST THEIR QPF FROM EAST- CENTRAL INTO SOUTH- CENTRAL NEW MEXICO. WHERE THIS BANDS SET UP WILL LIKELY MEAN THE DIFFERENCE BETWEEN A HIGH-END ADVISORY FOR SEVERAL INCHES OF SNOW OR NO ADVISORY. FOR NOW HAVE KEPT WITH PREVIOUS STRONG TREND TOWARD THE GFS. BOTTOM LINE...WE ARE NOT DONE WITH SNOW IMPACTS. THEREAFTER...A BRUTALLY COLD PATTERN MONDAY NIGHT ESPECIALLY WITH FRESH SNOW COVER AND CLEARING SKIES FOR SOME AREAS. OTHERWISE A QUIET PATTERN FINALLY INDICATED INTO TUESDAY WITH ANY LINGERING SNOW ENDING FROM EAST TO WEST. WE WILL FINALLY BEGIN TO MAKE THE TURN BY THE MIDDLE PART OF THE WEEK BUT STILL UNCERTAINTY REGARDING HOW A LOW LATITUDE LOW MAY EVOLVE FOR THE LATE WEEK PERIOD. KJ && .FIRE WEATHER... NOW HAS BEGUN ACROSS THE NORTH AND WEST THIS MORNING AS AN UPPER LEVEL TROUGH SWINGS OVER NM. VERY HIGH SNOW RATIOS EXPECTED WITH THIS COLD AIRMASS...AND SEVERAL INCHES OF SNOW HAS ALREADY BEEN REPORTED ACROSS THE SAN JUAN MOUNTAINS. COLD FRONT IS MARCHING INTO NORTHWEST NM AND IS CURRENTLY THROUGH FARMINGTON AND GALLUP. THIS FRONT WILL CONTINUE TO SWEEP EASTWARD TODAY CREATING WINDY CONDITIONS BEHIND IT...ESPECIALLY ACROSS THE CENTRAL MOUNTAIN CHAIN AND ADJACENT HIGHLANDS TO THE EAST. THE INCREASE IN WIND SPEED WILL RESULT IN VERY GOOD TO EXCELLENT VENTILATION FOR ALL BUT THE SOUTHERN PORTIONS OF THE RIO GRANDE VALLEY AND THE EAST CENTRAL PLAINS. ALSO BECAUSE OF THE WINDS...SPECIFICALLY THE DOWNSLOPE COMPONENT ACROSS THE EAST...TEMPERATURES ARE EXPECTED TO WARM ABOVE THE FREEZING MARK FOR THE FIRST TIME IN SEVERAL DAYS...THOUGH MOST AREAS WILL REMAIN 10 TO 20 DEGREES BELOW NORMAL. THE WARM-UP TODAY WILL BE SHORT-LIVED AS MUCH COLDER AIR FILTERS INTO THE AREA TONIGHT...AND MOST AREAS ON MONDAY WILL STRUGGLE TO REACH THE FREEZING MARK. A SECONDARY TROUGH WILL SWING OVER THE STATE ON MONDAY AS WELL...AND OPERATIONAL MODELS ARE STILL AT ODDS WITH PRECIPITATION POTENTIAL. HOWEVER...GFS ENSEMBLE GUIDANCE INCREASES CONFIDENCE THAT THERE WILL BE A BAND OF SNOW DEVELOPING ALONG A FRONT STRETCHING FROM THE SW MTNS TOWARD THE SANDIA/MANZANO MOUNTAINS. ADDITIONALLY...CONVERGENCE DUE TO THE BACK DOOR SEGMENT OF THE FRONT MAY ENHANCE SNOWFALL POTENTIAL OVER THE CENTRAL AND SOUTH CENTRAL HIGHLANDS. SHOULD THIS OCCUR A COUPLE INCHES OF SNOW ARE POSSIBLE...THOUGH IT SHOULD BE MENTIONED THAT THE NAM AND ECMWF MODELS SHOW VERY LITTLE QPF...IF ANY. WINDS DUE TO THE FRONT WILL KEEP VENT RATES IN THE GOOD TO VERY GOOD CATEGORY MONDAY ACROSS THE CENTRAL AND WEST...WITH POOR VENTILATION PREVAILING ACROSS THE EAST. COOL NORTHWEST FLOW WILL BE IN STORE FOR TUESDAY AND WEDNESDAY...AND TEMPERATURES WILL REMAIN UP TO 20 DEGREES BELOW NORMAL. GENERALLY LIGHT WINDS AND POOR MIXING WILL RESULT IN POOR VENTILATION AREAWIDE. HOWEVER...A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS ON WEDNESDAY. MODELS SHOW A DISTURBANCE MOVING ACROSS THE AREA ON THURSDAY...THOUGH IT IS UNCLEAR WHERE...IF ANY...PRECIPITATION OCCURS WITH THIS SYSTEM. MIXING WILL REMAIN POOR...THUS SO WILL VENTILATION. THE UPPER AIR PATTERN LOOKS TO REMAIN ACTIVE BEYOND THURSDAY...THOUGH MODELS DIVERGE ON PLACEMENT AND TIMING OF STORM SYSTEMS. 34 && .AVIATION... 06Z TAF CYCLE IFR AND MVFR CIGS COVERAGE HAS DECREASED IN VCNTY OF RIO GRANDE VALLEY...BUT MVFR TO LOCALLY IFR CIGS MAY REDEVELOP IN THIS AREA AFTER 10Z...MUCH MORE SO THOUGH NORTH OF INTERSTATE 40. SAF TAF SITE SHOULD SEE SIGNIFICANT IMPROVEMENT TO SCT OR AT LEAST HIGHER CIGS BETWEEN 07Z AND 10Z WITH SOME LOWERING AGAIN THEREAFTER. SOME CIG HEIGHT RISES AT LVS AND PERHAPS ROW AFTER 11Z...BUT LESS LIKELY THAN SAF TO IMPROVE TO SCT CLOUDS. OTHERWISE MOST OF THE EASTERN PLAINS LIKELY TO STAY IN PRETTY SOLID MVFR TO IFR CIGS OVERNIGHT WITH IMPROVEMENT TO SCT AFTER 15Z. CIGS AND VSBY LOWERING EXPECTED AFTER 06Z AT FMN AND GUP WITH SOME AREAS OF LIGHT TO BRIEFLY MODERATE SNOW. MT OBSCURATIONS LIKELY MOST PEAKS AND RANGES OVERNIGHT. WINDS IN THE LOWER BOUNDARY LAYER WILL LIKELY INCREASE MODESTLY OVERNIGHT WITH GREATER INCREASES HIGHER TERRAIN...BUT STRONGER WINDS LIKELY ACROSS MUCH OF THE AREA LATE MORN AND AFTN SUNDAY. 43 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 26 5 21 -1 / 30 0 5 0 DULCE........................... 23 -4 18 -16 / 40 5 5 0 CUBA............................ 27 6 21 -7 / 40 10 20 0 GALLUP.......................... 31 4 25 -8 / 30 5 20 0 EL MORRO........................ 31 1 25 -10 / 40 10 30 5 GRANTS.......................... 34 8 28 -5 / 30 5 20 0 QUEMADO......................... 38 15 29 -1 / 30 5 20 5 GLENWOOD........................ 44 22 38 12 / 10 5 20 0 CHAMA........................... 19 -8 13 -16 / 60 10 5 0 LOS ALAMOS...................... 30 9 23 -2 / 40 10 30 5 PECOS........................... 27 8 20 -1 / 30 10 30 5 CERRO/QUESTA.................... 22 -4 16 -13 / 40 10 10 0 RED RIVER....................... 17 -6 11 -16 / 60 10 20 0 ANGEL FIRE...................... 21 -10 15 -18 / 50 10 20 5 TAOS............................ 25 0 19 -14 / 30 5 10 0 MORA............................ 26 4 20 -4 / 30 5 30 5 ESPANOLA........................ 33 11 27 3 / 20 5 10 0 SANTA FE........................ 28 9 21 1 / 30 10 20 5 SANTA FE AIRPORT................ 31 12 24 2 / 20 5 20 5 ALBUQUERQUE FOOTHILLS........... 36 17 30 6 / 10 5 30 5 ALBUQUERQUE HEIGHTS............. 37 20 30 10 / 5 0 30 0 ALBUQUERQUE VALLEY.............. 39 15 32 5 / 5 0 30 0 ALBUQUERQUE WEST MESA........... 38 18 31 9 / 5 0 30 0 LOS LUNAS....................... 42 21 34 9 / 5 0 30 0 RIO RANCHO...................... 37 18 31 9 / 10 0 30 0 SOCORRO......................... 48 24 37 15 / 0 0 30 5 SANDIA PARK/CEDAR CREST......... 33 10 26 -3 / 30 10 40 5 TIJERAS......................... 34 12 27 -5 / 20 5 40 5 MORIARTY/ESTANCIA............... 32 -1 26 -13 / 20 5 30 10 CLINES CORNERS.................. 30 11 21 2 / 30 5 50 20 GRAN QUIVIRA.................... 37 18 29 7 / 20 0 40 20 CARRIZOZO....................... 43 24 37 16 / 10 0 40 20 RUIDOSO......................... 38 21 32 16 / 10 0 50 30 CAPULIN......................... 28 3 16 2 / 10 5 10 5 RATON........................... 29 2 20 -2 / 20 5 10 5 SPRINGER........................ 31 4 21 -3 / 10 5 10 5 LAS VEGAS....................... 29 8 20 -1 / 20 5 20 10 CLAYTON......................... 33 6 18 7 / 5 5 10 10 ROY............................. 33 7 19 3 / 5 5 20 10 CONCHAS......................... 41 12 25 6 / 5 0 30 10 SANTA ROSA...................... 41 15 26 10 / 5 0 30 20 TUCUMCARI....................... 45 12 28 10 / 0 5 20 20 CLOVIS.......................... 44 15 26 14 / 0 5 20 20 PORTALES........................ 44 16 27 13 / 0 0 20 20 FORT SUMNER..................... 43 18 29 13 / 0 5 20 20 ROSWELL......................... 49 25 36 19 / 0 0 10 30 PICACHO......................... 47 24 34 17 / 0 0 30 30 ELK............................. 46 24 34 18 / 0 0 40 30 && .ABQ WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ521>524-526>529-533-539-540. WINTER WEATHER ADVISORY UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ501-502-504>506-511-512-515>517. WINTER STORM WARNING UNTIL 4 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ503-510-513-514. && $$ 41
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
148 PM EST SUN DEC 8 2013 .SYNOPSIS... CHILLY AND DAMP CONDITIONS WILL PREVAIL TODAY BEFORE A WARM FRONT BRINGS A SHORT-LIVED WARM-UP ON MONDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY...BRINGING A REINFORCEMENT OF COOLER AIR THROUGH MID WEEK. ANOTHER STORM SYSTEM MAY BRING RAIN TO THE REGION NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY...PERSISTENCE EMPLOYED FOR THE NEAR TERM UPDATE AS THE METEOROLOGICAL SET-UP SUPPORTS A COOL AND WET REGIME TO PREVAIL ALL DAY AND OVERNIGHT. NEAR TERM MODEL DATA HOWEVER POINTS TO ATYPICAL TEMPERATURE CURVES TONIGHT...WITH A SLOW CLIMB FROM THE MIDDLE AND UPPER 40S TO AROUND 50 DEGREES BY DAYBREAK MONDAY AS SW FLOW ALOFT STRENGTHENS AND SCOURS THE SHALLOW AND COOL WEDGE OF MARITIME INFLUENCE. HOW QUICKLY THIS OCCURS REMAINS UP FOR ASSESSMENT...BUT IT APPEARS THE WEDGE WILL REMAIN ENTRENCHED OVER THE FORECAST AREA THROUGH DAYBREAK MONDAY. THIS MAKE TEMP AND WIND FORECASTS A BIT MORE PREDICTABLE THAN THE TRANSITION OF WARMING ON MONDAY MORNING. MAXIMUM TEMPERATURES AS A RESULT WILL LIKELY OCCUR FOR TODAYS 24 HOUR CALENDER PERIOD JUST PRIOR TO 12Z/7AM MONDAY MORNING. PRECIPITATION-WISE THE OVER-RUNNING WEDGE PATTERN WILL SUPPORT OCCASIONAL DRIZZLE AREA-WIDE THROUGH TONIGHT. IN FACT AS THE WARM FRONTAL TYPE PROCESS GEARS UP EARLY ON MONDAY...AREAS OF DENSE FOG AND DRIZZLE MAY EXPAND OVER THE FORECAST AREA TO START THE WEEK. P-TYPE ANALYSIS SHOWS THAT BOTH STRATIFORM AND CONVECTIVE TYPE RAINFALL WILL PREVAIL OVER THE AREA THROUGH TONIGHT...BUT NOT A LARGE OR SIGNIFICANT CONTRIBUTION FROM EITHER. WILL CONTINUE TO ADVERTISE SCATTERED TO LIKELY POP VALUES TO HIGHLIGHT DECENT PROBABILITIES OF MEASURABLE PRECIPITATION HOWEVER ACCOMPANIED BY INTERMITTENT DRIZZLE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...SHARP CLASSIC COLD AIR DAMMING EVENT WILL COME TO AN END EARLY IN THE PERIOD WITH THE FORECAST DILEMMA BEING FORECAST HIGHS FOR MONDAY. THE MET CONTINUES TO ADVERTISE THE COOLER NUMBERS AND WITH LINGERING LOW LEVEL MOISTURE AND NEARING THE WINTER SOLSTICE...THESE SEEM MORE REASONABLE ALTHOUGH WITH ANY APPRECIABLE CLOUD OR EARLY BREAKS...VERY WARM TEMPERATURES IN THE 850-900MB LAYER COULD MIX DOWN. THE FORECAST SOLUTIONS REGARDING THE FRONT TUESDAY CONTINUE TO WAVER AND SLOW THE PROGRESSION OF THE FRONT. IN FACT...THE GFS SHOWS A SECONDARY AREA OF QPF DEVELOPING WITH THE SOUTHWEST FLOW WEDNESDAY THUS SLOWING THE FRONT FOR TUESDAY. THIS IS THE FIRST CYCLE THIS HAS APPEARED SO I DID MAINTAIN THE LIKELY POPS FOR TUESDAY AND INCREASED THE LONGEVITY OF THE MOISTURE FOR TUESDAY EVENING. NO CHANGES TO TEMPERATURE FORECAST FOR TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...CONFIDENCE HAS WALKED BACK SLIGHTLY WITH REGARDS TO THE EVENTS FOR THE EXTENDED FORECAST. THE NEW AND WETTER SOLUTION AS ADVERTISED BY THE GFS OPERATIONAL PUTS WEDNESDAY IN QUESTION ALTHOUGH I DID NOT CHANGE THE DRY FORECAST AT LEAST FOR NOW TO SEE IF MORE SOLUTIONS COME IN SIMILAR. THE GFS ALSO CONTINUES TO SHOW A FAIRLY STRONG SOUTHERN STREAM SYSTEM FOR THE END OF THE WEEK INSTEAD OF THE WEAKLY FORCED COASTAL TROUGH. I HAVE ALONG WITH ADJACENT OFFICES INCREASED POPS AND CLOUD COVER FOR THE END OF THE PERIOD. NO CHANGES TO THE TEMPERATURE FORECAST ALTHOUGH ONCE AGAIN THE READINGS MAY SEE SOME CHANGES DEPENDING ON THE MASS FIELDS. && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... AS OF 18Z...WEDGE WILL LIKELY REMAIN IN PLACE THROUGH MUCH OF THE FORECAST PERIOD. HIGH CONFIDENCE FOR IFR CONDITIONS THIS AFTERNOON...POSSIBLY BECOMING VLIFR TONIGHT. THE WARM AIR WILL START TO OVERRIDE THE WEDGE LATE TONIGHT. THE RISING DEWPOINTS COUPLED WITH DIURNAL AFFECTS SHOULD BE A GOOD RECIPE FOR DENSE FOG TONIGHT. WOULD NOT BE SURPRISED TO SEE SOME M1/4SM ESPECIALLY OVER THE SOUTHERN TERMINALS. MONDAY...DENSE FOG WILL LINGER THROUGH MID MORNING AT THE COASTAL TERMINALS...LIFTING AS WINDS SHIFT TO THE SOUTHWEST AS THE WEDGE ERODES. INLAND TERMINALS MAY SEE LIFR/IFR CONDITIONS THROUGH THE END OF THE FORECAST PERIOD AS THE WEDGE IN TYPICAL FASHION WILL BE STUBBORN TO RETREAT. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH TUESDAY WITH LIFR/IFR/MVFR CONDITIONS DUE TO A NEARLY STATIONARY. SHOWERS LIKELY TUESDAY FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE. MODERATE CONFIDENCE FOR VFR CONDITIONS WEDNESDAY THROUGH FRIDAY...EXCEPT POSSIBLY THE COAST WEDNESDAY NIGHT. SHOWERS POSSIBLE SATURDAY. && .MARINE... NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1025 AM SUNDAY...THE SCA HAS BEEN EXTENDED TO MID- AFTERNOON TODAY FOR ALL WATERS. THE NE WINDS CONTINUE TO HOWL AT 15 TO 25 KT WITH GUSTS APPROACHING 30 KT OFF CAPE FEAR EARLY THIS MORNING. WITH A SLIGHTLY SLOWER BREAKDOWN IN THE WEDGE BEING FORECAST DURING THIS PERIOD...HAVE SLOWED THE DIMINISHING TREND OF THE NE WINDS ACROSS THE LOCAL WATERS TODAY THROUGH TONIGHT. THIS IS DEPICTED WELL BY THE HOURLY HRRR MODEL RUNS ILLUSTRATING PROGGED SFC WINDS. THIS WILL ALSO PRODUCE A SLOWER SUBSIDING TREND TO THE SIGNIFICANT SEAS FROM ROUGHLY 4 TO 7 FT EARLY THIS AM...TO 2 TO 5 FT BY SUNDAY EVENING. THE MAKE-UP OF THE SIGNIFICANT SEAS WILL REMAIN FROM THE LOCALLY PRODUCED WIND DRIVEN VARIETY...WITH AVERAGE PERIODS AROUND 5 SECONDS. SEA FOG MAY BECOME AN ISSUE ONCE AGAIN DURING THE PRE-DAWN MONDAY HRS BUT LIKELY HOLD OFF INTO THE NEXT PERIOD WHEN S-SW WINDS ACROSS LOCAL SSTS IN THE 50S OCCUR. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...LIGHT AND ESSENTIALLY VARIABLE WINDS WILL QUICKLY FIND DEFINITION AS A SOUTHWEST FLOW OF 15-20 KNOTS DEVELOPS MIDDAY MONDAY. THIS FLOW WILL CONTINUE THROUGH MOST OF THE DAY TUESDAY BEFORE A LONG ADVERTISED FRONT MOVES ACROSS THE WATERS. BY 0600 UTC WEDNESDAY WINDS WILL BE NORTH ACROSS ALL WATERS WITH THE SAME 15-20 KNOTS. THE CHANGE IN FETCH AND THE FACT WINDS SEEM TO REMAIN CAPPED AT 20 KNOTS SHOULD KEEP SEAS BELOW FLAG CRITERIA IN A 2-4 FOOT RANGE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...A NORTH TO NORTHEASTERLY FLOW WILL GREET MARINERS INITIALLY WITH A FEW HOURS OF 15-20 KNOTS DIMINISHING SLIGHTLY TO 10-15 KNOTS BY WEDNESDAY EVENING. SLOW MOVING HIGH PRESSURE AND LOW PRESSURE WELL OFFSHORE WILL KEEP THIS FLOW IN PLACE THROUGH THURSDAY. SEAS SHOULD REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ250- 252-254-256. && $$ NEAR TERM...DOUG/MJC SHORT TERM...SHK LONG TERM...SHK AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1025 AM EST SUN DEC 8 2013 .SYNOPSIS... CHILLY AND DAMP CONDITIONS WILL PREVAIL TODAY BEFORE A WARM FRONT BRINGS A SHORT-LIVED WARM-UP ON MONDAY. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY...BRINGING A REINFORCEMENT OF COOLER AIR THROUGH MID WEEK. ANOTHER STORM SYSTEM MAY BRING RAIN TO THE REGION NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY...PERSISTENCE EMPLOYED FOR THE NEAR TERM UPDATE AS THE METEOROLOGICAL SET-UP SUPPORTS A COOL AND WET REGIME TO PREVAIL ALL DAY AND OVERNIGHT. NEAR TERM MODEL DATA HOWEVER POINTS TO ATYPICAL TEMPERATURE CURVES TONIGHT...WITH A SLOW CLIMB FROM THE MIDDLE AND UPPER 40S TO AROUND 50 DEGREES BY DAYBREAK MONDAY AS SW FLOW ALOFT STRENGTHENS AND SCOURS THE SHALLOW AND COOL WEDGE OF MARITIME INFLUENCE. HOW QUICKLY THIS OCCURS REMAINS UP FOR ASSESSMENT...BUT IT APPEARS THE WEDGE WILL REMAIN ENTRENCHED OVER THE FORECAST AREA THROUGH DAYBREAK MONDAY. THIS MAKE TEMP AND WIND FORECASTS A BIT MORE PREDICTABLE THAN THE TRANSITION OF WARMING ON MONDAY MORNING. MAXIMUM TEMPERATURES AS A RESULT WILL LIKELY OCCUR FOR TODAYS 24 HOUR CALENDER PERIOD JUST PRIOR TO 12Z/7AM MONDAY MORNING. PRECIPITATION-WISE THE OVER-RUNNING WEDGE PATTERN WILL SUPPORT OCCASIONAL DRIZZLE AREA-WIDE THROUGH TONIGHT. IN FACT AS THE WARM FRONTAL TYPE PROCESS GEARS UP EARLY ON MONDAY...AREAS OF DENSE FOG AND DRIZZLE MAY EXPAND OVER THE FORECAST AREA TO START THE WEEK. P-TYPE ANALYSIS SHOWS THAT BOTH STRATIFORM AND CONVECTIVE TYPE RAINFALL WILL PREVAIL OVER THE AREA THROUGH TONIGHT...BUT NOT A LARGE OR SIGNIFICANT CONTRIBUTION FROM EITHER. WILL CONTINUE TO ADVERTISE SCATTERED TO LIKELY POP VALUES TO HIGHLIGHT DECENT PROBABILITIES OF MEASURABLE PRECIPITATION HOWEVER ACCOMPANIED BY INTERMITTENT DRIZZLE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...SHARP CLASSIC COLD AIR DAMMING EVENT WILL COME TO AN END EARLY IN THE PERIOD WITH THE FORECAST DILEMMA BEING FORECAST HIGHS FOR MONDAY. THE MET CONTINUES TO ADVERTISE THE COOLER NUMBERS AND WITH LINGERING LOW LEVEL MOISTURE AND NEARING THE WINTER SOLSTICE...THESE SEEM MORE REASONABLE ALTHOUGH WITH ANY APPRECIABLE CLOUD OR EARLY BREAKS...VERY WARM TEMPERATURES IN THE 850-900MB LAYER COULD MIX DOWN. THE FORECAST SOLUTIONS REGARDING THE FRONT TUESDAY CONTINUE TO WAVER AND SLOW THE PROGRESSION OF THE FRONT. IN FACT...THE GFS SHOWS A SECONDARY AREA OF QPF DEVELOPING WITH THE SOUTHWEST FLOW WEDNESDAY THUS SLOWING THE FRONT FOR TUESDAY. THIS IS THE FIRST CYCLE THIS HAS APPEARED SO I DID MAINTAIN THE LIKELY POPS FOR TUESDAY AND INCREASED THE LONGEVITY OF THE MOISTURE FOR TUESDAY EVENING. NO CHANGES TO TEMPERATURE FORECAST FOR TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...CONFIDENCE HAS WALKED BACK SLIGHTLY WITH REGARDS TO THE EVENTS FOR THE EXTENDED FORECAST. THE NEW AND WETTER SOLUTION AS ADVERTISED BY THE GFS OPERATIONAL PUTS WEDNESDAY IN QUESTION ALTHOUGH I DID NOT CHANGE THE DRY FORECAST AT LEAST FOR NOW TO SEE IF MORE SOLUTIONS COME IN SIMILAR. THE GFS ALSO CONTINUES TO SHOW A FAIRLY STRONG SOUTHERN STREAM SYSTEM FOR THE END OF THE WEEK INSTEAD OF THE WEAKLY FORCED COASTAL TROUGH. I HAVE ALONG WITH ADJACENT OFFICES INCREASED POPS AND CLOUD COVER FOR THE END OF THE PERIOD. NO CHANGES TO THE TEMPERATURE FORECAST ALTHOUGH ONCE AGAIN THE READINGS MAY SEE SOME CHANGES DEPENDING ON THE MASS FIELDS. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... AS OF 15Z...PREDOMINATELY IFR CONDITIONS THIS MORNING WITH STRATUS AND OCCASIONAL LIGHT DRIZZLE. THERE IS A BATCH OF HEAVIER SHOWERS NOW MOVING THROUGH THE NORTHERN THIRD OF THE CWA...ASSOCIATED WITH A WEAK DISTURBANCE. EXPECT THIS AREA OF SHOWERS TO MOVE NORTHEAST AND OUT OF THE REGION BY 13Z. THE WEDGE WILL PROBABLY STAY IN PLACE THROUGH THE FORECAST PERIOD...PERHAPS LIFTING ALONG THE COAST BY 10-11Z ON MONDAY. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE EXTENDED PERIOD WITH LIFR/IFR/MVFR CONDITIONS DUE TO A NEARLY STATIONARY FRONT THROUGH MONDAY. SHOWERS LIKELY TUESDAY FOLLOWED BY ANOTHER COLD FRONTAL PASSAGE. && .MARINE... NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1025 AM SUNDAY...THE SCA HAS BEEN EXTENDED TO MID- AFTERNOON TODAY FOR ALL WATERS. THE NE WINDS CONTINUE TO HOWL AT 15 TO 25 KT WITH GUSTS APPROACHING 30 KT OFF CAPE FEAR EARLY THIS MORNING. WITH A SLIGHTLY SLOWER BREAKDOWN IN THE WEDGE BEING FORECAST DURING THIS PERIOD...HAVE SLOWED THE DIMINISHING TREND OF THE NE WINDS ACROSS THE LOCAL WATERS TODAY THROUGH TONIGHT. THIS IS DEPICTED WELL BY THE HOURLY HRRR MODEL RUNS ILLUSTRATING PROGGED SFC WINDS. THIS WILL ALSO PRODUCE A SLOWER SUBSIDING TREND TO THE SIGNIFICANT SEAS FROM ROUGHLY 4 TO 7 FT EARLY THIS AM...TO 2 TO 5 FT BY SUNDAY EVENING. THE MAKE-UP OF THE SIGNIFICANT SEAS WILL REMAIN FROM THE LOCALLY PRODUCED WIND DRIVEN VARIETY...WITH AVERAGE PERIODS AROUND 5 SECONDS. SEA FOG MAY BECOME AN ISSUE ONCE AGAIN DURING THE PRE-DAWN MONDAY HRS BUT LIKELY HOLD OFF INTO THE NEXT PERIOD WHEN S-SW WINDS ACROSS LOCAL SSTS IN THE 50S OCCUR. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...LIGHT AND ESSENTIALLY VARIABLE WINDS WILL QUICKLY FIND DEFINITION AS A SOUTHWEST FLOW OF 15-20 KNOTS DEVELOPS MIDDAY MONDAY. THIS FLOW WILL CONTINUE THROUGH MOST OF THE DAY TUESDAY BEFORE A LONG ADVERTISED FRONT MOVES ACROSS THE WATERS. BY 0600 UTC WEDNESDAY WINDS WILL BE NORTH ACROSS ALL WATERS WITH THE SAME 15-20 KNOTS. THE CHANGE IN FETCH AND THE FACT WINDS SEEM TO REMAIN CAPPED AT 20 KNOTS SHOULD KEEP SEAS BELOW FLAG CRITERIA IN A 2-4 FOOT RANGE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...A NORTH TO NORTHEASTERLY FLOW WILL GREET MARINERS INITIALLY WITH A FEW HOURS OF 15-20 KNOTS DIMINISHING SLIGHTLY TO 10-15 KNOTS BY WEDNESDAY EVENING. SLOW MOVING HIGH PRESSURE AND LOW PRESSURE WELL OFFSHORE WILL KEEP THIS FLOW IN PLACE THROUGH THURSDAY. SEAS SHOULD REMAIN IN A 2-4 FOOT RANGE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ250- 252-254-256. && $$ NEAR TERM...DOUG/MJC SHORT TERM...SHK LONG TERM...SHK AVIATION...DL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1254 AM EST SUN DEC 8 2013 .SYNOPSIS... A COLD FRONT WILL STALL SOUTH OF THE REGION INTO SUNDAY THEN LIFT BACK NORTH THROUGH THE AREA SUNDAY NIGHT. ANOTHER COLD FRONT WILL APPROACH FROM THE WEST MONDAY AND CROSS EARLY TUESDAY. COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY INTO FRIDAY. WEAK LOW PRESSURE WILL DEVELOP NEAR THE COAST LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1250 AM SUNDAY...PRECIPITATION IS LIMITED TO THE IMMEDIATE COASTAL AREAS AND HAVE MADE CHANGES TO THE POPS TO REFLECT THE CURRENT RADAR TRENDS WITH MINIMAL POPS INLAND. LATEST 3 KM HRRR AND RAP INCREASES PRECIPITATION INLAND AFTER 12Z WITH INCREASING ISENTROPIC LIFT MOVING INLAND. NO OTHER BIG CHANGES TO THE FORECAST AS TEMPERATURES WILL REMAIN FAIRLY STEADY GIVEN THE CLOUDINESS AND N/NE WINDS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... AS OF 215 PM SATURDAY...ISENT LIFT WILL GRAD LIFT N OF REGION SUNDAY BUT STILL LOOKS LIKE DECENT CVRG OF RAIN/DRIZZLE ESPCLY EARLY ALL AREAS AND ACROSS THE N LATER. DID NOT CHANGE POPS WHICH HAVE LIKELY ALL AREAS EARLY...DIMINISHING TO CHC S AS BEST LIFTS SHIFTS TO THE N. COOL NE FLOW WILL PERSIST INLAND WITH HIGHS IN THE 40S...ALONG THE CST MAY SEE SOME LOW TO MID 50S AS LOW LVL FLOW BECOMES A LITTLE MORE ONSHORE. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS OF 330 PM SAT...AN UPPER TROUGH WILL REMAIN CENTERED OVER THE CENTRAL/WESTERN CONUS AS A STRONG RIDGE ALOFT REMAINS CENTERED OVER FLORIDA AND THE SE CONUS...PLACING EASTERN NC IN SW FLOW ALOFT THROUGH EARLY IN THE WEEK. WEAK SFC LOW/WARM FRONT WILL DEVELOP SUN NIGHT AND MOVE NNE WITH RETURN SW FLOW TAKING OVER WITH EASTERN NC AGAIN IN THE WARM SECTOR. RAIN CHANCES WILL END DRASTICALLY SUN NIGHT...THOUGH FCST SNDGS INDICATE OVERCAST LOW CLOUDS/MIST AND POSSIBLE PATCHY DRIZZLE SUN NIGHT WITH WARM FRONT MOVING NORTHWARD. MAY SEE SOME SUNSHINE BREAK THROUGH ON MONDAY AS SW WINDS BRING WARMING TEMPS INTO THE MID 60S NORTHWEST TO NEAR 70 SOUTH. RAIN EXPECTED ONCE AGAIN MON NIGHT INTO TUE AS A FRONTAL BOUNDARY PUSHES THROUGH FROM THE NORTH. PRECIP CHANCES INC FROM NORTH TO SOUTH BEGINNING MON NIGHT. LOTS OF MOISTURE AVAILABLE WITH THIS FRONTAL SYSTEM AS PLENTY OF GULF OF MEXICO MOISTURE IN SW FLOW ALOFT. MAINTAINED LIKELY POPS DUE TO STRONG AGREEMENT AMONGST OPER MODEL RUNS BETWEEN GFS/ECMWF AND ECMWF ENSEMBLE MEAN. FOR HIGH TEMPS TUE...LOW CONFIDENCE AS TIMING OF THE FRONTAL BOUNDARY THROUGH E NC WILL DICTATE WHETHER WARMER TEMPS NEAR 70 ARE REALIZED OR TEMPS REMAIN IN THE 50S. GFS/NAM ARE SLOWER WITH THE FRONT BRINGING IT THROUGH TUE AFTERNOON...WHILE FASTER ECMWF PUSHES THE FRONT THROUGH BY TUE MORNING. IF SLOWER GFS/NAM SOLN VERIFY COULD SEE SOME THUNDERSTORMS AS INSTABILITY WILL BE PRESENT WITH SOLAR HEATING DURING THE DAY TUE. FOR NOW...HAVE COMPROMISED AND HAVE COOLER 50S NORTH TO NEAR 70 ON THE CRYSTAL COAST AND KEPT THUNDER OUT OF THE FCST. TEMPS SHOULD EXHIBIT A NON- DIURNAL CURVE AS WARMEST READINGS REALIZED EARLY TUE. RAIN WILL QUICKLY END BY TUES EVENING FROM NW TO SE AS THE FRONT SWEEPS OFFSHORE. MUCH COOLER/DRIER AIR WILL FILTER IN BEHIND THE FRONT WED/THURS WITH HIGHS IN THE UPPER 40S/LOW 50S WITH LOWS BELOW FREEZING MOST AREAS INLAND. MODEST AGREEMENT THURS AFTERNOON WITH A WEAK LOW DEVELOPING OFFSHORE OF SC/GA WHICH MAY WRAP AROUND SOME CLOUDS INTO THE EASTERN HALF OF THE CWA...THUS MAINTAINED SLIGHT CHANCE POPS WED NIGHT/THURS FOR THE COAST. NAEFS POPS AND ECM SOLN REMAIN MAINLY DRY HOWEVER SO AM DISCOUNTING THE WETTER GFS SOLN. ANY OFFSHORE LOW WILL SHIFT WELL AWAY FROM THE AREA LATE THUR WITH A RETURN TO DRY CONDITIONS OVER THE AREA THROUGH FRI...WITH TEMPS STILL 5-8 F BELOW NORMAL FOR MID DECEMBER. 07/12Z OPERATIONAL RUNS OF THE GFS/ECM INDICATE NEXT POSSIBLE STORM SYSTEM MOVING UP OUT OF THE GOM LATE IN THE WEEK AS NEXT SHORTWAVE DIGS THROUGH THE CENTRAL CONUS...SO HAVE INCLUDED CHANCE POPS FOR LATE IN THE PERIOD INTO NEXT WEEKEND. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... SHORT TERM /THROUGH 00Z MONDAY/... AS OF 1250 PM SAT...PRECIPITATION IS NOW LIMITED TO COASTAL SECTIONS WITH MVFR CEILINGS AT KEWN AND KOAJ WITH VFR AT BOTH KISO AND KPGV CURRENTLY. WITH INCREASING ISENTROPIC LIFT AFTER 12Z...HAVE TRENDED CEILINGS DOWN TO IFR AT ALL TAF SITES THROUGH THE DAY SUNDAY. LONG TERM /SUNDAY NIGHT THROUGH THU/... AS OF 330 PM SAT..A WEAK LOW OFF THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW TAKING OVER AND PRECIP CHANCES DIMINISHING. HOWEVER...SOUNDINGS INDICATE PLENTY OF LOW LEVEL MOISTURE REMAINING IN PLACE BRINGING POSSIBLE LIFR CIGS AND BR TO THE TERMINALS...ALONG WITH SOME PATCHY DRIZZLE. LOW CLOUDS SHOULD LIFT MON AS SW FLOW INCREASES. ANOTHER COLD FRONT CROSSES THE TERMINALS FROM NW TO SE TUES WITH ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED CEILINGS/VSBYS MON NIGHT THROUGH TUE. HIGH PRESSURE BUILDS OVER THE REGION TUES NIGHT THROUGH MID TO LATE WEEK WITH VFR RETURNING IN MOSTLY SUNNY SKIES. && .MARINE... SHORT TERM /THROUGH SUN/... AS OF 1255 AM SUNDAY...GUSTY N/NNE WINDS CONTINUE OVER THE COASTAL WATERS AND SOUNDS. WIND GUSTS CURRENTLY UP TO 30 KNOTS AT THE BUOY 13 MILES EAST OF OREGON INLET. SEAS THERE HAVE ALSO BUILT TO 9 FEET. MADE JUST MINOR TWEAKS TO THE CURRENT FORECAST AS THESE TRENDS SHOULD CONTINUE OVERNIGHT AND THRU SUNDAY. LONG TERM /SUNDAY NIGHT THROUGH THU/... AS OF 330 PM SAT...WEAK SURFACE LOW MOVES NNE ALONG THE NC COAST SUN NIGHT. SURFACE WINDS WILL BECOME W ONCE THE WEAK LOW LIFTS NORTH OF THE WATERS SUN NIGHT. SW WINDS EXPECTED MON NIGHT AND PEAK AROUND 15 KT BY EVENING. WINDS SHIFT N AND INCREASE 15-20 KT DUE TO POST- FRONTAL CAA SURGE ASSOCIATED WITH STRONG HIGH PRESSURE BUILDING OVER THE WATERS BEGINNING TUES AFTERNOON AND LASTING INTO WED. SEAS BUILD 4-7 FT LATE TUES/TUES NIGHT. REINFORCING COLD AIR SURGE POSSIBLE BY THUR KEEPING SCA CONDITIONS A THREAT FOR MUCH OF THE COASTAL WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ135. SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ150- 152-154. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ156- 158. && $$ SYNOPSIS...RF NEAR TERM...CTC SHORT TERM...RF LONG TERM...TL AVIATION...CTC/TL MARINE...CTC/TL/LEP
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
959 PM EST MON DEC 9 2013 .SYNOPSIS... WEAK SYSTEM LATE TONIGHT INTO TUESDAY WITH SOME SNOW. CHILLY DRY HIGH PRESSURE WEDNESDAY. ARCTIC FRONT WEDNESDAY NIGHT. ARCTIC HIGH PRESSURE THURSDAY EXITS FRIDAY. ANOTHER SYSTEM THIS WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... 10 PM UPDATE...UPDATED SNOW GRIDS BASED ON CURRENT MODEL RUNS. MADE LITTLE CHANGES TO OVERALL TOTALS. STILL LOOKING AT 1 TO 2 ACROSS MUCH OF THE NORTH...WITH 2 TO 4 ACROSS CENTRAL AND NORTHERN WV LOWLANDS...AND 2 TO 5 AS A GENERAL RULE ACROSS THE MOUNTAINS. NEW MODEL RUNS STARTING TO HIT HARDER ON QPF FOR BAND OF SNOWFALL ACROSS SOUTHEAST OHIO THIS EVENING. AT THIS POINT...DID UP SNOWFALL TOTALS...BUT KEPT BELOW ADVISORY CRITERIA AT THIS POINT. WILL ALLOW THE MIDNIGHT SHIFT TO KEEP AN EYE ON AND ADD AN ADVISORY TO THESE AREAS IF NEED BE. PREVIOUS DISCUSSION FOLLOWS... KEPT SOME DZ IN WX GRIDS A FEW MORE HRS THIS AFTN ALONG AND E OF I79 CORRIDOR. THINK THE LOW CRUD STRATUS HOLDS INTO THE OVERNIGHT ACROSS THE LOWLANDS AND PORTIONS OF THE MTNS. MAY SEE SOME BREAKS ACROSS NE KY/SE OH AND W LOWLANDS BEFORE FILLING BACK IN LATE AHEAD OF THE NEXT SYSTEM. TEMPS WILL GRADUALLY FALL TONIGHT WITH POTENTIAL FOR SOME PATCHY BLACK ICE FOR ANY UNTREATED SURFACES THAT HAVE LINGERING MOISTURE. NOW FOR UPCOMING SYSTEM. GFS...NAM AND 00Z RUNS OF HI RESOLUTION WRFS DEPICT A BAND OF ADVISORY LEVEL SNOW FROM NEAR MT STERLING TO HUNTINGTON...NE THRU CHARLESTON...CLARKSBURG AND N MTNS. THE SREF...GEM...AND RUC WOULD HAVE THE HIGHER QPF FURTHER E...CLOSER TO THE BAROCLINIC ZONE. THIS CREATES TWO CAMPS REGARDING SNOW ACCUMS WITH ADVISORY LEVEL SNOW FROM THE LATTER GROUP PRIMARILY ACROSS THE MOUNTAINS. HPC WWD ALSO NOTED THIS SPLIT IN THEIR WINTER QPF GRIDS. WILL TRY TO TAKE A BLEND WITH THIS WHICH WOULD WARRANT ADVISORIES FOR ALL OF WV COUNTIES ALONG WITH SW VA AND PORTIONS OF NE KY. THERE IS ENOUGH AGREEMENT TO LEAVE OUT SE OH AS THIS AREA MAY BE BETWEEN SFC WAVE AND BAND FROM UPPER LEVEL TROF AS WELL AS GREENUP AND CARTER AND NEW 18Z NAM ROLLING HAS SHIFTED E MORE IN LINE WITH SREF/CMC/RUC. NONETHELESS HAVE ISSUED HEADLINES RUNNING FROM 06Z TO 20Z ALTHOUGH THE END TIME MAY BE ABLE TO DROP EARLY. APPEARS HIGHER AMOUNTS WOULD BE ACROSS THE N LOWLANDS AND N MTNS AS THE UPPER TROF APPROACHES TO HELP IN SOME MESOSCALE BANDING VIA SOME SLANTWISE INSTABILITY AND JET DYNAMICS. THIS IS WHERE SOME 2 TO 4 WAS CODED UP FOR C AND N LOWLANDS WITH 3 TO 6 FOR N MOUNTAINS. 1 TO 3 S WV/SW VA WITH LESS THAN AN INCH SE OH TO OH RIVR. BAND WITH THE UPPER TROF LOOKS TO AFFECT N REACHES OF SE OH COUNTIES...IE PERRY/MORGAN. ALSO SE WV/BKW...AND SW VA...THERMAL PROFILES INDICATE POTENTIAL FOR A MIX. UPPER SYS AND SFC WAVE QUICKLY PULLS E BY 18Z WITH SOME PARTIAL CLEARING ACROSS SE OH INTO NE KY. HAVE KEPT TEMPS BELOW FREEZING ALL LOCATIONS TOMORROW WITH ONLY A MODEST REBOUND AFTER THE SNOW MOVES OUT. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... HAVING TRANSITIONED TO ZONAL UPPER LEVEL FLOW FROM SW JUST PRIOR TO THE START OF THIS PERIOD...THE FLOW TRANSITIONS FARTHER...TO WNW TO NW...AS L/W TROUGHING MOVES FROM THE CENTER OF THE CONTINENT TO THE EASTERN HALF. FLURRIES IN THE COLD ADVECTION UPSLOPE WNW LOW LEVEL FLOW RIGHT AT THE START OPF THE PERIOD...WIND DOWN OVERNIGHT...AS HIGH PRESSURE BUILDS INTO THE S. A CLIPPER SYSTEM / ARCTIC FRONT MOVES THROUGH LATE WED NT...REINFORCING THE COLD AIR. SNOW SHOWERS WITH THIS MOISTURE STARVED SYSTEM WILL BE LIMITED TO UPSLOPE IN THE MOUNTAINS MAINLY IN THE COLD ADVECTION WNW FLOW ONCE THE FRONT PASSES OVERNIGHT WED NT. ARCTIC HIGH PRESSURE BUILDS IN ON THU. TEMPERATURES TEN TO FIFTEEN DEGREES BELOW NORMAL THIS PERIOD. LOWS TUE NT LOOKED GOOD WITH MINOR CHANGES ONLY. BLENDED IN BIAS CORRECTED ADJMET FOR HIGHS WED...A LITTLE LOWER IN THE N. BLENDED IN BIAS CORRECTED CONSENSUS MOS FOR LOWS WED NT...A LITTLE HIGHER WITH CLIPPER COMING THROUGH EXCEPT LITTLE OR NO CHANGE NW IN THE WAKE OF THE CLIPPER. BLENDED IN ADJMEX AND BIAS CORRECTED ECMWFHIRES FOR LOWER HIGHS IN THE ARCTIC AIR ON THU. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... MODELS SHOWING AN INTERESTING SYSTEM FOR SATURDAY INTO SUNDAY...WITH POTENTIAL WINTER WEATHER ON THE ONSET. STILL LOTS OF SPREAD IN THE MODELS HOWEVER...SO WOULD NOT PUT MUCH STOCK IN THE DETAILS AT THIS TIME. USED A BLEND OF THE GEFS MEAN/ECMWF MEAN/GFS AND ECMWF. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... 00Z TUESDAY THROUGH 00Z WEDNESDAY PRIMARILY MVFR STRATUS INTO TONIGHT WITH SOME IFR CIGS/VSBY IN THE MOUNTAINS AMID PATCHY DZ. AN UPPER DISTURBANCE WILL MOVE INTO THE REGION LATE TONIGHT...WITH SNOW DEVELOPING ACROSS THE AREA GENERALLY AFTER 07Z. BULK OF PRECIPITATION WILL GENERALLY BE ALONG AND SOUTH/EAST OF A LINE FROM CKB TO CRW TO HTS. EXPECT WIDESPREAD IFR AND LIFR CONDITIONS IN SNOW. SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST AFTER 15Z TUESDAY...WITH A GRADUAL RETURN TO MVFR CONDITIONS...WITH SOME IMPROVEMENT TO VFR GENERALLY AFTER 20Z...MAINLY ACROSS SOUTHEAST OHIO...NORTHEAST KENTUCKY...AND WV COUNTIES NEAR TO THE OHIO RIVER. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 12/10/13 UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13 EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08 CRW CONSISTENCY H H H H H H M M M M M M HTS CONSISTENCY H H H M H H H M L M M M BKW CONSISTENCY M M L M M H H H M H H M EKN CONSISTENCY L L L L L L L L M M M H PKB CONSISTENCY H H H H H H M L L M M M CKB CONSISTENCY H H H H H H H M M M M M AFTER 00Z WEDNESDAY... IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND SUNDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR WVZ005>011-013>020-024>040-046-047. OH...NONE. KY...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR KYZ103-105. VA...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR VAZ003-004. && $$ SYNOPSIS...TRM/RPY/30 NEAR TERM...SL/30 SHORT TERM...TRM LONG TERM...RPY AVIATION...SL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
952 PM EST MON DEC 9 2013 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST TONIGHT. A FAST MOVING LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE NORTHERN GREAT LAKES REGION TUESDAY WITH A REINFORCING ARCTIC COLD FRONT. HIGH PRESSURE WILL BUILD EAST INTO THE OHIO VALLEY ON THURSDAY AND TO THE EAST COAST ON FRIDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... TWO AREAS OF CONCERN. ONE IS THE POTENTIAL FOR SOME LAKE EFFECT SNOW FOR THE SNOW BELT AREA LATE TONIGHT. THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C BY DAYBREAK TUESDAY. ONE TO LOCALLY TWO INCHES OF SNOW MAY ACCUMULATE. SOME RIDGING WILL HELP KEEP THE SNOWFALL AMOUNTS DOWN. AN IMPULSE IN THE SOUTHWEST FLOW ALOFT WILL CAUSE SOME SNOW IN THE SOUTHERN PORTION OF THE FORECAST AREA AFTER MIDNIGHT...THIS IS IN THE RIGHT REAR QUAD OF THE JET. BASED ON THE RUC MODEL INCREASED THE POPS A LITTLE. THE SNOWFALL AMOUNTS COULD BE AROUND AN INCH. MADE MINOR ADJUSTMENTS TO THE LOWS BASED ON SOME CLOUDS AND WIND. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/... SOME SNOW SHOWERS LINGERS IN THE SNOW BELT AS THE WINDS WILL BECOME SOUTHWEST AND SHIFT THE BANDS INTO THE LAKE. THE SNOW/SNOW SHOWERS OVER THE SE PORTION OF THE FORECAST AREA WILL BE QUICKLY MOVING OUT. ANOTHER FRONT WILL BE MOVING THROUGH THE REGION ON TUESDAY AND THE WINDS ALOFT NEAR THE FRONTAL BOUNDARY WILL BE NEAR 40 KNOTS. ADDED GUSTS UP TO 40 MPH IN THE AFTERNOON. SOME BREAKS IN THE CLOUDS WILL HELP BRING DOWN SOME OF THE WIND. ALSO DEBATED ABOUT ISSUING A LAKE EFFECT WATCH FOR THE SNOW BELT FOR LATE TUESDAY NIGHT INTO THURSDAY. WITH THE 18Z DATA STILL SOME QUESTIONS ABOUT THE WIND DIRECTION AND THE AMOUNT OF MOISTURE. THE GFS IS THE MOST PESSIMISTIC. THE CANADIAN MODEL IS VERY DRY. WITH THAT WILL LET THE MID NIGHT SHIFT TAKE ANOTHER LOOK BEFORE ISSUING OR NOT ISSUING THE LAKE EFFECT WATCH. PREVIOUS DISCUSSION... THE FIRST HALF OF TUESDAY WILL GENERALLY BE DRY AND COOL UNDER THE INFLUENCE OF HIGH PRESSURE. BY TUESDAY EVENING THE NEXT TROUGH ARRIVES AND LAKE EFFECT SNOW WILL SET UP ACROSS NW PA/NE OH. WILL HOLD OFF ON A LAKE EFFECT SNOW WATCH FOR THIS PACKAGE...WITH THE HEAVIEST SNOW NOT FALLING UNTIL OUTSIDE THE THIRD PERIOD. LAKE EFFECT WILL WIND DOWN BY THURSDAY AFTERNOON. MOST AREAS OUTSIDE OF THE SNOWBELT WILL BE DRY. WEDNESDAY NIGHT LOW TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BEHIND AN ARCTIC COLD FRONT. && .LONG TERM /FRIDAY THROUGH MONDAY/... THE MODELS ARE A LITTLE MORE IN AGREEMENT THE SECOND HALF OF THE WEEK WITH HIGH PRESSURE SLIDING EAST AND THE FLOW BACKING TO SOUTHWEST BY FRIDAY. THIS WILL PUT AN END TO THE LAKE EFFECT THREAT. TEMPERATURES SHOULD BOTTOM OUT ON THURSDAY AS SOME OF THE ARCTIC AIR FILTERS ACROSS THE AREA. THE TREND UPWARD WILL BE RELATIVELY SLOW AS MOST OF THE COUNTRY WILL BE TRYING TO MODIFY FROM ARCTIC AIR AND OF COURSE THE SUN ANGLE IS AT A MINIMUM THIS TIME OF YEAR. FORECAST HIGHS MOSTLY IN THE TEENS THURSDAY AND 20S ON FRIDAY. STILL NO CONFIDENCE ON THE SCENARIO FOR SATURDAY. THE MODELS SHOW A DECENT SHORT WAVE AND CORRESPONDING SURFACE LOW TRACKING FROM THE SOUTH CENTRAL STATES AND ENDING UP ALONG THE MID ATLANTIC COAST. THESE SYSTEMS OFTEN REDEVELOP FROM THE OHIO VALLEY TO THE EAST COAST AND WE END UP IN THE TRANSITION ZONE SO NOT A LOT OF CONFIDENCE ON THE STRENGTH AND TRACK OF THE SURFACE LOW YET. THE FORECAST WILL GO FOR TEMPERATURES NEAR FREEZING ON SATURDAY AND A CHANCE OF SNOW. WE MAY END UP NEEDING HIGHER POPS AND A MIX OF PRECIPITATION BUT WILL WAIT TO SEE THE MODEL TRENDS THIS WEEK. COLDER AGAIN BY SUNDAY INTO MONDAY AS THE PATTERN REMAINS COLD. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... BACK EDGE OF MVFR STRATO CU NOW WORKING ACROSS THE TOL AND FDY AREAS. NOW SURE HOW FAR EAST THIS BACK EDGE WILL MAKE IT BEFORE A WEAK MID LEVEL SYSTEM SPREADS LIGHT SNOW NE ACROSS THE SE PART OF THE AREA LATER TONIGHT. THIS SNOW WILL GENERALLY BE LIGHT AND SHORT LIVED...PROBABLY LASTING ONLY ABOUT 4 TO 6 HOURS AT CAK...YNG AND MAYBE AT MFD AND ERI. ERI WILL ALREADY HAVE AN ONGOING THREAT FOR SHSN AS LAKE EFFECT CONDITIONS CONTINUE WITH MEAN LOW LEVEL WINDS VEERING JUST ENOUGH TO BRING THE SNOW BANDS INTO THE ERI AREA TONIGHT. AN AREA OF DRYER LOW LEVEL AIR WORKS EAST ACROSS THE TAF SITES AND LOOKS TO BE OVER TOL...FDY AND MFD BY MID MORNING AND OVER THE EASTERN SITES EARLY TO MID AFTERNOON. SHOULD SEE SITES LIFT TO VFR AS THE DRYER AIR MOVES IN. HOWEVER...AT ERI CONDITIONS LOOK GOOD ENOUGH FOR LAKE EFFECT SHSN TO CONTINUE TO PESTER THE AREA THRU THE DAY OR AT LEAST BE ON THE NORTH SIDE OF THE AIRSPACE. WINDS MAY GUST AROUND 20 KNOTS NEAR THE LAKESHORE TONIGHT THEN INCREASE AGAIN LATER TUE MORNING INTO MID TUE AFTERNOON TO BE GUSTING 25 TO 30 KNOTS WITH THE HIGHER GUSTS AT TOL AND FDY AND ALONG THE LAKESHORE. OUTLOOK...NON VFR CONDITIONS WILL LINGER AT TIMES THROUGH THURSDAY...MAINLY OVER NE OH/NW PA. && .MARINE... ALLOWING GALE WARNING TO EXPIRE AS PLANNED AT 7 PM. IF WIND FORECAST NEEDS TO BE INCREASED A LITTLE MORE WITH NEW 00Z DATA ON THE MID SHIFT THEN WILL LIKELY NEED ANOTHER GALE FOR THE EAST HALF OF THE LAKE FOR LATER TUE INTO TUE NIGHT. OTHERWISE...SCA CONDITIONS WILL TEND TO PREVAIL INTO THU WEST PART AND INTO THU NIGHT EAST PART. THERE WILL BE A BRIEF LULL IN WINDS AND WAVES FOR THE WEST PART OF THE LAKE LATER TONIGHT INTO THE BEGINNING OF TUE BUT CONSENSUS IS TO JUST LEAVE THE SCA GOING SINCE CONDITIONS RAMP BACK UP QUICKLY LATER TUE MORNING. THE GRADIENT WILL REMAIN RATHER STRONG WEDNESDAY INTO THURSDAY...THEN RELAX AS THE SURFACE HIGH MOVES EAST ACROSS THE OHIO VALLEY. A STORM SYSTEM WILL AFFECT THE LOWER GREAT LAKES ON THE WEEKEND BUT NOT MUCH CONFIDENCE ON THE STRENGTH AND TRACK OF THE SYSTEM YET. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THURSDAY FOR LEZ145>149. SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR LEZ142>144. && $$ SYNOPSIS...MAYERS NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA/MAYERS LONG TERM...KOSARIK AVIATION...ADAMS MARINE...ADAMS/KOSARIK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
622 PM EST MON DEC 9 2013 .SYNOPSIS... WEAK SYSTEM LATE TONIGHT INTO TUESDAY WITH SOME SNOW. CHILLY DRY HIGH PRESSURE WEDNESDAY. ARCTIC FRONT WEDNESDAY NIGHT. ARCTIC HIGH PRESSURE THURSDAY EXITS FRIDAY. ANOTHER SYSTEM THIS WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... 630 PM UPDATE...NO MAJOR CHANGES TO THE FORECAST. WILL BE TAKING AN ADDITIONAL LOOK AT SNOW AMOUNTS LATER THIS EVENING. PREVIOUS DISCUSSION FOLLOWS... KEPT SOME DZ IN WX GRIDS A FEW MORE HRS THIS AFTN ALONG AND E OF I79 CORRIDOR. THINK THE LOW CRUD STRATUS HOLDS INTO THE OVERNIGHT ACROSS THE LOWLANDS AND PORTIONS OF THE MTNS. MAY SEE SOME BREAKS ACROSS NE KY/SE OH AND W LOWLANDS BEFORE FILLING BACK IN LATE AHEAD OF THE NEXT SYSTEM. TEMPS WILL GRADUALLY FALL TONIGHT WITH POTENTIAL FOR SOME PATCHY BLACK ICE FOR ANY UNTREATED SURFACES THAT HAVE LINGERING MOISTURE. NOW FOR UPCOMING SYSTEM. GFS...NAM AND 00Z RUNS OF HI RESOLUTION WRFS DEPICT A BAND OF ADVISORY LEVEL SNOW FROM NEAR MT STERLING TO HUNTINGTON...NE THRU CHARLESTON...CLARKSBURG AND N MTNS. THE SREF...GEM...AND RUC WOULD HAVE THE HIGHER QPF FURTHER E...CLOSER TO THE BAROCLINIC ZONE. THIS CREATES TWO CAMPS REGARDING SNOW ACCUMS WITH ADVISORY LEVEL SNOW FROM THE LATTER GROUP PRIMARILY ACROSS THE MOUNTAINS. HPC WWD ALSO NOTED THIS SPLIT IN THEIR WINTER QPF GRIDS. WILL TRY TO TAKE A BLEND WITH THIS WHICH WOULD WARRANT ADVISORIES FOR ALL OF WV COUNTIES ALONG WITH SW VA AND PORTIONS OF NE KY. THERE IS ENOUGH AGREEMENT TO LEAVE OUT SE OH AS THIS AREA MAY BE BETWEEN SFC WAVE AND BAND FROM UPPER LEVEL TROF AS WELL AS GREENUP AND CARTER AND NEW 18Z NAM ROLLING HAS SHIFTED E MORE IN LINE WITH SREF/CMC/RUC. NONETHELESS HAVE ISSUED HEADLINES RUNNING FROM 06Z TO 20Z ALTHOUGH THE END TIME MAY BE ABLE TO DROP EARLY. APPEARS HIGHER AMOUNTS WOULD BE ACROSS THE N LOWLANDS AND N MTNS AS THE UPPER TROF APPROACHES TO HELP IN SOME MESOSCALE BANDING VIA SOME SLANTWISE INSTABILITY AND JET DYNAMICS. THIS IS WHERE SOME 2 TO 4 WAS CODED UP FOR C AND N LOWLANDS WITH 3 TO 6 FOR N MOUNTAINS. 1 TO 3 S WV/SW VA WITH LESS THAN AN INCH SE OH TO OH RIVR. BAND WITH THE UPPER TROF LOOKS TO AFFECT N REACHES OF SE OH COUNTIES...IE PERRY/MORGAN. ALSO SE WV/BKW...AND SW VA...THERMAL PROFILES INDICATE POTENTIAL FOR A MIX. UPPER SYS AND SFC WAVE QUICKLY PULLS E BY 18Z WITH SOME PARTIAL CLEARING ACROSS SE OH INTO NE KY. HAVE KEPT TEMPS BELOW FREEZING ALL LOCATIONS TOMORROW WITH ONLY A MODEST REBOUND AFTER THE SNOW MOVES OUT. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... HAVING TRANSITIONED TO ZONAL UPPER LEVEL FLOW FROM SW JUST PRIOR TO THE START OF THIS PERIOD...THE FLOW TRANSITIONS FARTHER...TO WNW TO NW...AS L/W TROUGHING MOVES FROM THE CENTER OF THE CONTINENT TO THE EASTERN HALF. FLURRIES IN THE COLD ADVECTION UPSLOPE WNW LOW LEVEL FLOW RIGHT AT THE START OPF THE PERIOD...WIND DOWN OVERNIGHT...AS HIGH PRESSURE BUILDS INTO THE S. A CLIPPER SYSTEM / ARCTIC FRONT MOVES THROUGH LATE WED NT...REINFORCING THE COLD AIR. SNOW SHOWERS WITH THIS MOISTURE STARVED SYSTEM WILL BE LIMITED TO UPSLOPE IN THE MOUNTAINS MAINLY IN THE COLD ADVECTION WNW FLOW ONCE THE FRONT PASSES OVERNIGHT WED NT. ARCTIC HIGH PRESSURE BUILDS IN ON THU. TEMPERATURES TEN TO FIFTEEN DEGREES BELOW NORMAL THIS PERIOD. LOWS TUE NT LOOKED GOOD WITH MINOR CHANGES ONLY. BLENDED IN BIAS CORRECTED ADJMET FOR HIGHS WED...A LITTLE LOWER IN THE N. BLENDED IN BIAS CORRECTED CONSENSUS MOS FOR LOWS WED NT...A LITTLE HIGHER WITH CLIPPER COMING THROUGH EXCEPT LITTLE OR NO CHANGE NW IN THE WAKE OF THE CLIPPER. BLENDED IN ADJMEX AND BIAS CORRECTED ECMWFHIRES FOR LOWER HIGHS IN THE ARCTIC AIR ON THU. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... MODELS SHOWING AN INTERESTING SYSTEM FOR SATURDAY INTO SUNDAY...WITH POTENTIAL WINTER WEATHER ON THE ONSET. STILL LOTS OF SPREAD IN THE MODELS HOWEVER...SO WOULD NOT PUT MUCH STOCK IN THE DETAILS AT THIS TIME. USED A BLEND OF THE GEFS MEAN/ECMWF MEAN/GFS AND ECMWF. && .AVIATION /23Z MONDAY THROUGH SATURDAY/... 00Z TUESDAY THROUGH 00Z WEDNESDAY PRIMARILY MVFR STRATUS INTO TONIGHT WITH SOME IFR CIGS/VSBY IN THE MOUNTAINS AMID PATCHY DZ. AN UPPER DISTURBANCE WILL MOVE INTO THE REGION LATE TONIGHT...WITH SNOW DEVELOPING ACROSS THE AREA GENERALLY AFTER 07Z. BULK OF PRECIPITATION WILL GENERALLY BE ALONG AND SOUTH/EAST OF A LINE FROM CKB TO CRW TO HTS. EXPECT WIDESPREAD IFR AND LIFR CONDITIONS IN SNOW. SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST AFTER 15Z TUESDAY...WITH A GRADUAL RETURN TO MVFR CONDITIONS...WITH SOME IMPROVEMENT TO VFR GENERALLY AFTER 20Z...MAINLY ACROSS SOUTHEAST OHIO...NORTHEAST KENTUCKY...AND WV COUNTIES NEAR TO THE OHIO RIVER. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H H H H H M M M M HTS CONSISTENCY H H H H H H H H H M L M BKW CONSISTENCY H H H H L M M M M M M M EKN CONSISTENCY H H L L L L L L L L M M PKB CONSISTENCY H H H H H M M H M L L M CKB CONSISTENCY H H H H H H H H H M M M AFTER 00Z WEDNESDAY... IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND SUNDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR WVZ005>011-013>020-024>040-046-047. OH...NONE. KY...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR KYZ103-105. VA...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR VAZ003-004. && $$ SYNOPSIS...TRM/RPY/30 NEAR TERM...SL/30 SHORT TERM...TRM LONG TERM...RPY AVIATION...SL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 PM EST SUN DEC 8 2013 .SYNOPSIS... LOW PRESSURE TRAVELING UP THE APPALACHIANS WILL BRING A MIXTURE OF WINTRY PRECIPITATION TODAY INTO TONIGHT. HIGH PRESSURE WILL TRY TO BUILD IN ON MONDAY...BUT ANOTHER WEAK SYSTEM WILL AFFECT THE REGION ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DECENT ISENTROPIC LIFT COMBINING WITH UPR LEVEL DIVERGENCE FROM THE RR QUAD ENTRANCE REGION OF UPR LEVEL JET WILL PRODUCE WIDESPREAD PCPN ACRS THE REGION THIS MORNING INTO THE FIRST PART OF THIS AFTERNOON. WAA WILL GRADUALLY WARM ATMOSPHERIC COLUMN ALOFT FROM SE TO NW THROUGH THE DAY. AS THIS OCCURS...SNOW WILL TRANSITION TO A MIXTURE OF SLEET AND FREEZING RAIN. IT SHOULD WARM UP ENOUGH IN THE FAR SE LATE THIS AFTERNOON FOR LIQUID PCPN. UPDATE THIS MORNING WAS TO BUMP UP SNOWFALL AMOUNTS A BIT IN THE SE CWFA AS SOME BURSTS OF MODERATE SNOW HAS ALREADY RESULTED IN ACCUMS AROUND AN INCH. SO...2 TO 3 LOOKS GOOD HERE WITH 1 TO 2 FARTHER NORTH IN DAYTON AND COLUMBUS METROS AND LESS THAN AN INCH NORTHWEST. LATEST MODEL INDICATE THAT WE COULD END UP WITH LIGHTER PCPN THIS EVENING/OVERNIGHT OVER MUCH OF THE REGION DUE TO DEEP MOISTURE EXITING AND FORCING REMAINING FOCUSED NEAR THE SE WITH A LOW LEVEL JET. WITH WARM TEMPS ALOFT AND SFC TEMPS NEAR OR SLIGHTLY BELOW FREEZING WILL RESULT IN EITHER LIGHT FREEZING RAIN OR FREEZING DRIZZLE. HEADLINES WILL HAVE TO BE ADJUSTED AT SOME POINT. TOSSED AROUND ADDING OUR NW CWFA IN AN ADVISORY...BUT WILL WAIT FOR SOME NEWER MODEL RUNS TO SEE IF PCPN WILL BE ENOUGH TO DO SO. TEMPS STARTING OUT COLD WITH ANY LIGHT LIQUID PCPN WITH SFC TEMPS BELOW FREEZING COULD CAUSE SOME ISSUES ON UNTREATED SIDEWALKS AND ROADS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE DEEP MOISTURE BEGINS TO BE SHUNTED E AT THE BEGINNING OF THE PERIOD...LEAVING THE W WITH VERY SHALLOW MOISTURE AND WEAKENING LIFT. THIS IS A SETUP FOR MORE OF A FZDZ/FZRA SCENARIO AS COMPARED TO SN/PL. THEREFORE BEGAN TO LOWER THE POPS IN THE W AND INTRODUCED MORE OF THE FZDZ/FZRA. EXPECT MUCH OF THE AREA TO MAKE THE CHANGE OVER AS TONIGHT PROGRESSES. THE EXCEPTION WILL BE THE SE/E WHERE TEMPERATURES MIGHT STAY UP ALL NIGHT THEREFORE STAYING ALL RAIN. THE ADVISORY IN THOSE LOCATIONS MIGHT BE TOO LONG...BUT WILL NOT CHANGE THE TIMING RIGHT NOW. INSTEAD WILL LET LATER SHIFTS CANCEL IT IF IT IS NOT NEEDED. LOWS TONIGHT SHOULD STAY UP IN THE LOWER TO MID 30S IN THE SE...BUT WILL FALL INTO THE UPPER 20S BACK TO THE W AS THE COOLER AIR WORKS IN ON THE BACKSIDE OF THE SYSTEM AS THE SYSTEM SLIDES E EARLY MONDAY...THE REGION WILL BE STUCK UNDER A SUBSIDENCE INVERSION...WHICH SHOULD KEEP LOW CLOUDS IN THROUGHOUT THE DAY. RIGHT NOW ENDED THE DZ/FZDZ MONDAY MORNING...BUT WITH THE LOW CLOUDS THE LIGHT PCPN COULD LINGER. MONDAY NIGHT INTO TUESDAY SEES A SPLIT LEVEL FLOW DEVELOP WITH A NRN STREAM VORT PIVOTING INTO THRU THE OHIO VALLEY LATE MONDAY NIGHT INTO TUESDAY. MODELS PRODUCE AN RIBBON OF SNOW ALONG THE LEADING EDGE OF THE ARCTIC AIR...WITH THE NAM THE QUICKEST AS IT PUSHES THE SNOW IN MONDAY NIGHT. THE GFS AND ECMWF WAIT UNTIL TUESDAY TO BRING THIS FEATURE IN. WILL LEAN TOWARD THE GFS/ECMWF SOLUTION AND WILL KEEP A MENTION OF SNOW ACRS SE HALF OF FA TUESDAY. HIGHS MONDAY AND TUESDAY WILL REMAIN MUCH BELOW NORMAL. ON MONDAY THEY WILL BE IN THE UPPER 20S IN THE NW TO THE MID 30S IN THE SE. THEN ON TUESDAY WITH THE WEATHER SYSTEM WORKING THROUGH HIGHS WILL ONLY REACH THE LOWE 20S IN THE N AND THE LOWER 30S IN THE S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE TO NOSE INTO THE OHIO VALLEY WEDNESDAY WITH WEAK SYSTEM DROPPING THRU THE GREAT LAKES. THE FAVORABLE MSTR/LIFT TO STAY TO OUR NORTH...SO HAVE MAINTAINED A DRY FCST WED. COLD TEMPERATURES TO PERSIST WITH LOWS AROUND 10 DEGREES WEST TO 15 DEGREES SE AND HIGHS LOWER/MIDDLE 20S NW TO THE LOWER 30S SE. SFC HIGH PRESSURE TO BUILD ACRS THE REGION THURSDAY/FRIDAY TIME FRAME. COLD TEMPERATURES TO CONTINUE THURSDAY WITH MORNING LOWS FROM SINGLE DIGITS OVER THE WEST WHERE SNOW COVER EXISTS TO NEAR 15 SE. HIGHS TO RANGE FROM THE LOWER 20S NW TO NEAR 30 SE. SOME MODERATION TO TEMPERATURES EXPECTED FRIDAY ON BACK SIDE OF SFC HIGH PRESSURE WITH HIGHS FROM LOWER 30S NW TO THE UPPER 30S SE. MID LEVEL FLOW BACKS WITH SYSTEM EXPECTED TO DEVELOP ALONG THE EASTERN SEABOARD LATE FRIDAY INTO SATURDAY. ILN FA IS ON THE FAR NW FRINGE OF THIS SYSTEM AND HAVE LIMITED ANY MENTION OF PRECIP TO A SLIGHT CHC OF A SNOW SHOWER IN THE FAR SE LATE FRIDAY NIGHT INTO SATURDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... STRONGEST WAA ASSOCIATED WITH UPPER LEVEL JET ENERGY WAS PIVOTING NE OUT OF THE TAF REGION THIS AFTERNOON. A MIXTURE OF LIGHT SNOW...SLEET AND FREEZING RAIN WILL TRANSITION OVER TO SOME PATCHY LIGHT FREEZING RAIN OR LIGHT FREEZING DRIZZLE AS DEEP MOISTURE GETS REPLACED WITH LOW LEVEL MOISTURE...WICH WILL LACK ICE NUCLEATION FOR SNOW DEVELOPMENT. FOR TONIGHT...A FRONTAL BOUNDARY WILL APPROACH THE REGION FROM THE WEST AND WILL PUSH ACROSS THE TAF SITES LATE TONIGHT INTO MONDAY. CONTINUED MOIST LOW LEVEL WAA AHEAD OF THE FRONT WILL RESULT IN LOW CEILINGS AND VISIBILITIES...ALONG WITH SOME LIGHT FREEZING RAIN/LIGHT FREEZING DRIZZLE OR IN THE LIQUID FORM AT SOME POINT (KCMH/KLCK) BEFORE THE FRONT PUSHES BY. KEPT VISIBILITIES AS LOW AS 1SM BUT WOULD NOT BE SURPRISED IF SOME POCKETS OF 1/2SM OR LESS DEVELOP. ONCE THE FRONT MOVES THROUGH...DRIER AIR IN THE LOWER LEVELS WILL RESULT IN A SLOW IMPROVEMENT IN VISIBILITIES AND CEILINGS ON MONDAY...WITH MVFR CEILINGS AT LEAST CONTINUING INTO THE AFTERNOON HOURS. OUTLOOK...MVFR CEILINGS TO LINGER INTO MONDAY EVENING. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR OHZ045-046- 051>056-060>065-070>074-077>082-088. KY...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...CONIGLIO/SITES NEAR TERM...HICKMAN/SITES SHORT TERM...SITES LONG TERM...AR AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
956 AM EST SUN DEC 8 2013 .SYNOPSIS... LOW PRESSURE TRAVELING UP THE APPALACHIANS WILL BRING A MIXTURE OF WINTRY PRECIPITATION TODAY INTO TONIGHT. HIGH PRESSURE WILL TRY TO BUILD IN ON MONDAY...BUT ANOTHER WEAK SYSTEM WILL AFFECT THE REGION ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DECENT ISENTROPIC LIFT COMBINING WITH UPR LEVEL DIVERGENCE FROM THE RR QUAD ENTRANCE REGION OF UPR LEVEL JET WILL PRODUCE WIDESPREAD PCPN ACRS THE REGION THIS MORNING INTO THE FIRST PART OF THIS AFTERNOON. WAA WILL GRADUALLY WARM ATMOSPHERIC COLUMN ALOFT FROM SE TO NW THROUGH THE DAY. AS THIS OCCURS...SNOW WILL TRANSITION TO A MIXTURE OF SLEET AND FREEZING RAIN. IT SHOULD WARM UP ENOUGH IN THE FAR SE LATE THIS AFTERNOON FOR LIQUID PCPN. UPDATE THIS MORNING WAS TO BUMP UP SNOWFALL AMOUNTS A BIT IN THE SE CWFA AS SOME BURSTS OF MODERATE SNOW HAS ALREADY RESULTED IN ACCUMS AROUND AN INCH. SO...2 TO 3 LOOKS GOOD HERE WITH 1 TO 2 FARTHER NORTH IN DAYTON AND COLUMBUS METROS AND LESS THAN AN INCH NORTHWEST. LATEST MODEL SINDICATE THAT WE COULD END UP WITH LIGHTER PCPN THIS EVENING/OVERNIGHT OVER MUCH OF THE REGION DUE TO DEEP MOISTURE EXITING AND FORCING REMAINING FOCUSED NEAR THE SE WITH A LOW LEVEL JET. WITH WARM TEMPS ALOFT AND SFC TEMPS NEAR OR SLIGHTLY BELOW FREEZING WILL RESULT IN EITHER LIGHT FREEZING RAIN OR FREEZING DRIZZLE. HEADLINES WILL HAVE TO BE ADJUSTED AT SOME POINT. TOSSED AROUND ADDING OUR NW CWFA IN AN ADVISORY...BUT WILL WAIT FOR SOME NEWER MODEL RUNS TO SEE IF PCPN WILL BE ENOUGH TO DO SO. TEMPS STARTING OUT COLD WITH ANY LIGHT LIQUID PCPN WITH SFC TEMPS BELOW FREEZING COULD CAUSE SOME ISSUES ON UNTREATED SIDEWALKS AND ROADS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE DEEP MOISTURE BEGINS TO BE SHUNTED E AT THE BEGINNING OF THE PERIOD...LEAVING THE W WITH VERY SHALLOW MOISTURE AND WEAKENING LIFT. THIS IS A SETUP FOR MORE OF A FZDZ/FZRA SCENARIO AS COMPARED TO SN/PL. THEREFORE BEGAN TO LOWER THE POPS IN THE W AND INTRODUCED MORE OF THE FZDZ/FZRA. EXPECT MUCH OF THE AREA TO MAKE THE CHANGE OVER AS TONIGHT PROGRESSES. THE EXCEPTION WILL BE THE SE/E WHERE TEMPERATURES MIGHT STAY UP ALL NIGHT THEREFORE STAYING ALL RAIN. THE ADVISORY IN THOSE LOCATIONS MIGHT BE TOO LONG...BUT WILL NOT CHANGE THE TIMING RIGHT NOW. INSTEAD WILL LET LATER SHIFTS CANCEL IT IF IT IS NOT NEEDED. LOWS TONIGHT SHOULD STAY UP IN THE LOWER TO MID 30S IN THE SE...BUT WILL FALL INTO THE UPPER 20S BACK TO THE W AS THE COOLER AIR WORKS IN ON THE BACKSIDE OF THE SYSTEM AS THE SYSTEM SLIDES E EARLY MONDAY...THE REGION WILL BE STUCK UNDER A SUBSIDENCE INVERSION...WHICH SHOULD KEEP LOW CLOUDS IN THROUGHOUT THE DAY. RIGHT NOW ENDED THE DZ/FZDZ MONDAY MORNING...BUT WITH THE LOW CLOUDS THE LIGHT PCPN COULD LINGER. MONDAY NIGHT INTO TUESDAY SEES A SPLIT LEVEL FLOW DEVELOP WITH A NRN STREAM VORT PIVOTING INTO THRU THE OHIO VALLEY LATE MONDAY NIGHT INTO TUESDAY. MODELS PRODUCE AN RIBBON OF SNOW ALONG THE LEADING EDGE OF THE ARCTIC AIR...WITH THE NAM THE QUICKEST AS IT PUSHES THE SNOW IN MONDAY NIGHT. THE GFS AND ECMWF WAIT UNTIL TUESDAY TO BRING THIS FEATURE IN. WILL LEAN TOWARD THE GFS/ECMWF SOLUTION AND WILL KEEP A MENTION OF SNOW ACRS SE HALF OF FA TUESDAY. HIGHS MONDAY AND TUESDAY WILL REMAIN MUCH BELOW NORMAL. ON MONDAY THEY WILL BE IN THE UPPER 20S IN THE NW TO THE MID 30S IN THE SE. THEN ON TUESDAY WITH THE WEATHER SYSTEM WORKING THROUGH HIGHS WILL ONLY REACH THE LOWE 20S IN THE N AND THE LOWER 30S IN THE S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HIGH PRESSURE TO NOSE INTO THE OHIO VALLEY WEDNESDAY WITH WEAK SYSTEM DROPPING THRU THE GREAT LAKES. THE FAVORABLE MSTR/LIFT TO STAY TO OUR NORTH...SO HAVE MAINTAINED A DRY FCST WED. COLD TEMPERATURES TO PERSIST WITH LOWS AROUND 10 DEGREES WEST TO 15 DEGREES SE AND HIGHS LOWER/MIDDLE 20S NW TO THE LOWER 30S SE. SFC HIGH PRESSURE TO BUILD ACRS THE REGION THURSDAY/FRIDAY TIME FRAME. COLD TEMPERATURES TO CONTINUE THURSDAY WITH MORNING LOWS FROM SINGLE DIGITS OVER THE WEST WHERE SNOW COVER EXISTS TO NEAR 15 SE. HIGHS TO RANGE FROM THE LOWER 20S NW TO NEAR 30 SE. SOME MODERATION TO TEMPERATURES EXPECTED FRIDAY ON BACK SIDE OF SFC HIGH PRESSURE WITH HIGHS FROM LOWER 30S NW TO THE UPPER 30S SE. MID LEVEL FLOW BACKS WITH SYSTEM EXPECTED TO DEVELOP ALONG THE EASTERN SEABOARD LATE FRIDAY INTO SATURDAY. ILN FA IS ON THE FAR NW FRINGE OF THIS SYSTEM AND HAVE LIMITED ANY MENTION OF PRECIP TO A SLIGHT CHC OF A SNOW SHOWER IN THE FAR SE LATE FRIDAY NIGHT INTO SATURDAY. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... CIGS WILL CONTINUE TO LOWER THIS MORNING AS MOISTURE OVERSPREADS THE ESTABLISHED COLD AIR DOME IN PLACE OVER THE OHIO VALLEY. CIGS WILL DROP TO THE MVFR CATEGORY IN A RAPID FASHION THIS MORNING AND LOWER TO IFR IN THE AFTERNOON. WHILE THE PLUME OF THE BEST MOISTURE WILL REMAIN SOUTHEAST OF THE I-71 CORRIDOR AND MAJORITY OF TAF SITES...A PROLONGED PERIOD OF LIGHT PRECIPITATION WILL OCCUR AND CIGS AT THE END OF THE VALID TAF ARE EXPECTED TO DIP TO THE LIFR OR VLIFR. AS FAR AS PTYPE GOES...SNOW WILL OCCUR IN THE MORNING AND TRANSITION TO A FREEZING RAIN MIXED IN WITH SLEET BY THE AFTERNOON. SOUNDINGS IN THE LATER AFTERNOON APPEAR TO HAVE THE TOP OF THE MOISTURE COLUMN STUCK BETWEEN 0 AND -5 DEGREES AND LACKING ANY DENDRITIC GROWTH...SUPPORTING SUB FREEZING RAINDROPS AND DRIZZLE WHICH WILL FREEZE ON SURFACES. TEMPERATURES MAY RISE TO ABOVE FREEZING IN THE LATE AFTERNOON AND MORESO OVERNIGHT BUT STILL LINGER AROUND THE FREEZING MARK AND ADD TO THE POSSIBILITY OF A PTYPE ISSUE. PRECIP THROUGH THE MAJORITY OF THE NEXT 24 HOURS WILL BE LIGHT BUT CIGS ARE EXPECTED TO DROP SIGNIFICANTLY GIVEN THE DEEP MOISTURE OVER THE REGION. WHILE A CHANGEOVER TO -SN IS EXPECTED BEFORE THE PRECIP ENTIRELY ENDS TONIGHT...VSBYS WILL REMAIN REDUCED BY MIST. DID NOT WANT TO KEEP AN IFR VSBY IN SNOW WHEN THE MAIN FACTOR REDUCING THE VSBY WAS THE MIST AND NOT PRECIP...EVEN IF SOME VERY LIGHT FLURRIES ARE POSSIBLE THROUGH DAYBREAK. VERY LITTLE CHANGE TO THE FORECAST AND MINUTE TIMING VARIABILITY IS FOUND AT ALL OF THE TAF FCSTS THIS MORNING. OUTLOOK...LIFR CIGS AND IFR VSBYS ARE LIKELY THROUGH MONDAY MORNING...WITH MVFR CONDITIONS CONTINUING THROUGH MONDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR OHZ045-046- 051>056-060>065-070>074-077>082-088. KY...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY UNTIL 4 AM EST MONDAY FOR INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...CONIGLIO/SITES NEAR TERM...HICKMAN/SITES SHORT TERM...SITES LONG TERM...AR AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
830 PM EST MON DEC 9 2013 .SYNOPSIS... A STRONG JET STREAM RESIDES TO THE NORTH AND WEST OF THE AREA. THE TAIL END OF THIS WEATHER FEATURE WILL HELP TO GENERATE AN AREA OF LOW PRESSURE AND SNOW OVER THE CENTRAL AND SOUTHERN APPALACHIAN MOUNTAINS TONIGHT. THAT AREA OF SNOW WILL MOVE NORTHEAST AND SPREAD ACROSS THE SOUTHERN HALF OF PENNSYLVANIA DURING THE MORNING AND EARLY AFTERNOON HOURS TUESDAY. BRISK WEST TO NORTHWEST WINDS WILL DEVELOP IN THE WAKE OF THIS STORM SYSTEM AND BRING MUCH COLDER AIR FOR THE MID TO LATE WEEK PERIOD. SCATTERED SNOW SHOWERS AND LOCALIZED...HEAVIER LAKE EFFECT SNOW ARE ALSO EXPECTED IN THE NORTHWESTERN PARTS OF THE STATE FOR THE REST OF THE WEEK. HOWEVER...IT WILL BE GENERALLY DRY AND COLD ELSEWHERE. THE WEEKEND LOOKS LIKE IT WILL BRING THE NEXT HIGH CHANCE OF WIDESPREAD PRECIPITATION. && .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/... LIGHT WIND...PARTIAL CLEARING BENEATH A THIN HIGH CLOUD DECK...AND SFC DEWPOINTS AT OR SLIGHTLY ABOVE FREEZING /AND THE FRESH SNOWPACK/ HAS RESULTED IN AREAS OF DENSE FOG NEAR AND TO THE SOUTH OF THE PA TURNPIKE ACROSS SCENT AND SERN PENN. SREF PROB OF LESS THAN ONE-QUARTER OF A MILE VBSYS INDICATES THAT WE SHOULD BE NEAR THE PEAK PERIOD OF DENSE FOG TONIGHT ATTM. POSTED A DENSE FOG ADVISORY UNTIL 08Z TUESDAY FOR 4 OF OUR SERN COUNTIES ALONG THE MASON/DIXON LINE. LATER TONIGHT...THE INCREASING WESTERLY WIND ABOVE THIS VERY SHALLOW SFC BASED INVERSION SHOULD SLOWLY MIX OUT THE LOW VSBYS /THOUGH LIGHT SNOW WILL BE SPREADING NE INTO THE REGION TWD DAYBREAK /SHORTLY AFTER THIS PERIOD OF IMPROVEMENT/. ELSEWHERE...WEAK LLVL ISENT UPGLIDE FROM THE WSW WILL CONTINUE TO MAINTAIN BKN-OVC STRATO CU TONIGHT WITH A SUSTAINED 10-15KT WSW SFC WIND /WITH GUSTS AROUND 20 KTS ACROSS THE WRN MTNS/. TEMPS WILL FALL BY ANOTHER 8-9 DEG F IN MOST PLACES OVERNIGHT... AND JUST REBOUND BY A FEW DEG F TUESDAY AS THE ARCTIC AIR TO OUR WEST SLOWLY PUSHES INTO THE COMMONWEALTH. LOWS AROUND DAYBREAK TUESDAY WILL BE IN THE MID TO UPPER TEENS ACROSS THE NW MTNS...IN THE LOWER TO MID 20S THROUGHOUT CENTRAL PENN...AND IN THE UPPER 20S IN THE LARGER METRO AREAS OF THE SOUTHEAST. RAPID DEVELOPMENT IN PRECIP WILL BE OCCURRING OVER THE TN VALLEY TONIGHT/EARLY TUESDAY...AS A VERY FAST JET STREAK WILL PULL LOTS OF MOISTURE NORTHEAST FROM THE GULF OF MEXICO. && .SHORT TERM /8 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... THE LACK OF NEG TILT TO THE TROUGH BEHIND THE JET AND LACK OF EASTERLY FLOW AT LLVLS WILL SPELL A QUICK SNOW EVENT FOR TUESDAY MORNING INTO THE EARLY AFTERNOON HOURS. THE LATEST MODEL RUNS SEEM TO BE TOO WET WITH THE FCST VS EARLIER GUIDANCE AND WITH WPC GUIDANCE. WILL MAINTAIN THE WINT WX ADVY FOR THE SRN HALF OF THE AREA AS QPF ON THE OF 0.25-0.35 INCHES AND A 12-15:1 RATIO ON AVERAGE WILL PRODUCE ADVY RANGE SNOWS FOR MOST OF THE REGION SOUTH OF STATE COLLEGE AND WILLIAMSPORT. NO WORRIES FOR MIX PRECIP WITH THIS EVENT. PROFILES ARE ALL COLD AND SNOW RATIOS NORTH OF RTE 22 MAY BE 20:1 OR HIGHER. THE SNOW SHOULD TAPER OFF THROUGH THE LATE MORNING AND EARLY AFTERNOON. THE WESTERLY FLOW WILL KEEP SOME SHSN IN THE FCST FOR THE WRN MTS...ESP WARREN CO...FOR THE AFTN AND INTO THE NEXT PERIOD. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... CORE OF STRONGEST JET /AND MAIN DRIVER OF PRECIPITATION/ WILL SLIDE EAST OF THE REGION BY TUE NIGHT. JET REMAINS POTENT THOUGH...WITH 500MB JET REMAINING NEAR 100 KTS AS FLOW TURNS WESTERLY BRINGING COLDER AIR INTO THE REGION. 850MB TEMPS FALL TO -15C ACROSS THE NW AS FLOW BECOMES UNIDIRECTIONAL WITH A CROSS LAKE FETCH. AS FLOW SNEAKS AROUND TO 290 DEGREES WE SHOULD SEE SOME LAKE INDUCED SNOW SHOWERS IMPACT MAINLY THE FAR NORTHERN MTNS TUE NIGHT INTO WED. CAA WILL BRING LOWS TUE NIGHT 5-10F COLDER THAN PREV NIGHT...WITH HIGHS ON WED ABOUT 10F BELOW NORMAL. ANOTHER WEAK WAVE SLIDING THROUGH THE FLOW WILL BRING POTENTIAL FOR A QUICK BOUT WITH LIGHT SNOW AGAIN WED NIGHT INTO EARLY THU. SYSTEM WON/T HAVE MUCH MOISTURE TO WORK WITH...SO MENTION OF SNOW WILL BE CONFINED MAINLY TO THE WESTERN/NORTHERN SECTIONS. CONTINUED HIGHEST POPS IN THE NW CLOSEST TO LAKE INFLUENCES...BUT BY THIS TIME THE FLOW VEERS BACK NEAR 270 DEGREES WHICH SHOULD PUSH HEAVIEST ACCUMS JUST NORTH OF PA BORDER. TEMPS COOL FURTHER WITH LOWS FROM 5 TO 15F AND HIGHS THU REMAINING IN THE TEENS ACROSS THE N AND W. HIGH PRESSURE EDGES IN FROM THE WEST LATER THU INTO SAT...BRINGING QUIETER BUT CHILLY WEATHER. TEMPS THU NIGHT WILL BE SIMILAR TO WED NIGHT...WITH A SLIGHT RECOVERY IN TEMPS FRI INTO FRI NIGHT. THIS WEEKEND...FLOW TURNS SOUTHWESTERLY BRINGING CONTINUED MODERATION TO TEMPERATURES. GFS COMING ON BOARD WITH ECMWF IN BRINGING ANOTHER WAVE OF LOW PRESSURE LATER SAT INTO SUNDAY. TEMPS SHOULD WARM ENOUGH TO BRING A RAIN/SNOW MIX ACROSS THE SE HALF...WITH CORE OF HEAVIEST PRECIP PROGGED TO REMAIN JUST SE OF THE CWA AT THIS TIME. ANOTHER SHOT OF COLD AIR SLIDES IN FOR EARLY NEXT WEEK. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... LOW CIGS/FOG PERSISTING EARLY THIS EVENING ACROSS EASTERN PA BENEATH TEMPERATURE INVERSION WITH LGT WINDS. A WEAK COLD FRONT...LOCATED ACROSS CENTRAL PA AT 23Z...WILL PUSH INTO EASTERN PA THIS EVENING. DOWNSLOPING WESTERLY FLOW BEHIND FRONT AND MIXING OF DRIER AIR ALOFT IS RESULTING IN CLEARING SKIES AT KIPT AS OF 23Z. HOWEVER...LATEST RAP AND SREF OUTPUT SUGGEST A MUCH MORE PESSIMISTIC OUTLOOK ACROSS SOUTHEAST PA...WITH LOW CIGS/FOG POTENTIALLY HANGING ON MUCH OF THE NIGHT AT KLNS. FORECAST UNCERTAINTY IS VERY HIGH IN THE NEAR TERM AT KMDT AND KLNS AND IS LINKED TO EXACTLY HOW FAR WEAKENING COLD FRONT AND DRY AIR MAKE IT INTO SE PA OVERNIGHT. ELSEWHERE...RESIDUAL LOW LVL MOISTURE FORCED TO ASCEND THE ALLEGHENY MTNS WILL LIKELY PRODUCE PERSISTENT MVFR STRATOCU OVERNIGHT AT KJST AND KBFD...WHILE ODDS FAVOR VFR CONDS FROM KAOO NE TO KIPT FOR MOST OF THE NIGHT. A FAST-MOVING LOW PRESSURE SYSTEM WILL TRACK SOUTH OF PA TUESDAY MORNING...SPREADING A PERIOD OF SNOW ACROSS MAINLY SOUTHERN PA BTWN 10Z-18Z. IFR VSBYS APPEAR LIKELY DURING LATE AM/EARLY AFTN AT KMDT AND KLNS. LIGHTER SNOW WILL FALL FURTHER NORTH. HOWEVER...A BRIEF DIP TO IFR VSBYS IS POSSIBLE ELSEWHERE TUE AM. IMPROVING CONDS ARE EXPECTED BY TUE AFTN AS THE LOW PRES SYSTEM PASSES OFF THE MID ATLANTIC COAST. OUTLOOK... WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS. THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS. FRI...NO SIG WX EXPECTED. SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 AM TO 4 PM EST TUESDAY FOR PAZ024>028-033>036-049>053-056>059-063>066. DENSE FOG ADVISORY UNTIL 3 AM EST TUESDAY FOR PAZ036-064>066. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...DANGELO/LAMBERT LONG TERM...RXR AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
714 PM EST MON DEC 9 2013 .SYNOPSIS... A STRONG JET STREAM RESIDES TO THE NORTH OF THE AREA. IT WILL PROVIDE FORCING TO GENERATE AN AREA OF SNOW OVER THE APPALACHIAN MOUNTAINS TONIGHT. THAT SNOW WILL MOVE ACROSS THE SOUTHERN HALF OF THE STATE DURING THE MORNING AND EARLY AFTERNOON. COLD WEST TO NORTHWEST WINDS WILL BRING COLDER AIR IN THROUGH THE REST OF THE WEEK. SCATTERED SNOW SHOWERS ARE ALSO EXPECTED IN THE NORTHWESTERN PARTS OF THE STATE FOR THE REST OF THE WEEK. BUT IT WILL BE GENERALLY DRY AND COLD ELSEWHERE. THE WEEKEND LOOKS LIKE IT WILL HOLD THE NEXT HIGH CHANCE OF WIDESPREAD PRECIPITATION. && .NEAR TERM /UNTIL 2 AM TUESDAY MORNING/... BIG BREAKS IN THE CLOUDS APPEARING THIS AFTERNOON AND SHOULD BECOME MORE PREVALENT THROUGH THE EVENING. A FEW FLURRIES/RAIN DROPS MAY BE FOUND IN THE WRN HIGHLANDS THRU THE EVENING...BUT DRYING FOUND ELSEWHERE. && .SHORT TERM /2 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... SNOW PACK WIDESPREAD OVER THE AREA...AND 8H TEMPS WILL ALSO FALL A FEW DEGREES. HOWEVER...THE WIND WILL REMAIN UP AROUND 10KTS ALL NIGHT - A LITTLE SLOWER IN THE VALLEYS AND FASTER ON THE RIDGES. THIS SHOULD RESULT IN MIN TEMPS IN THE UPPER TEENS IN THE NORTH AND M-U20S IN THE SE. RAPID DEVELOPMENT IN PRECIP WILL BE OCCURRING OVER THE TN VALLEY EARLY TONIGHT AS A VERY FAST JET STREAK WILL PULL LOTS OF MOISTURE NORTHEAST FROM THE GULF OF MEXICO. THE LACK OF NEG TILT TO THE TROUGH BEHIND THE JET AND LACK OF EASTERLY FLOW WILL SPEALL A QUICK EVENT FOR LATE TONIGHT AND TUESDAY. THE LATEST MODEL RUNS SEEM TO BE TOO WET WITH THE FCST VS EARLIER GUIDANCE AND WITH WPC GUIDANCE. HAVE POSTED A WINT WX ADVY FOR THE SRN HALF OF THE AREA AS QPF ON THE OF 0.25-0.35 INCHES AND A 15:1 RATIO ON AVERAGE WILL PRODUCE ADVY RANGE SNOWS FOR MOST OF THE REGION SOUTH OF STATE COLLEGE AND WILLIAMSPORT. NO WORRIES FOR MIX PRECIP WITH THIS EVENT. PROFILES ARE ALL COLD AND SNOW RATIOS NORTH OF RTE 22 MAY BE 20:1 OR HIGHER. THE SNOW SHOULD TAPER OFF THROUGH THE LATE MORNING AND EARLY AFTERNOON. THE WESTERLY FLOW WILL KEEP SOME SHSN IN THE FCST FOR THE WRN MTS...ESP WARREN CO...FOR THE AFTN AND INTO THE NEXT PERIOD. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... CORE OF STRONGEST JET /AND MAIN DRIVER OF PRECIPITATION/ WILL SLIDE EAST OF THE REGION BY TUE NIGHT. JET REMAINS POTENT THOUGH...WITH 500MB JET REMAINING NEAR 100 KTS AS FLOW TURNS WESTERLY BRINGING COLDER AIR INTO THE REGION. 850MB TEMPS FALL TO -15C ACROSS THE NW AS FLOW BECOMES UNIDIRECTIONAL WITH A CROSS LAKE FETCH. AS FLOW SNEAKS AROUND TO 290 DEGREES WE SHOULD SEE SOME LAKE INDUCED SNOW SHOWERS IMPACT MAINLY THE FAR NORTHERN MTNS TUE NIGHT INTO WED. CAA WILL BRING LOWS TUE NIGHT 5-10F COLDER THAN PREV NIGHT...WITH HIGHS ON WED ABOUT 10F BELOW NORMAL. ANOTHER WEAK WAVE SLIDING THROUGH THE FLOW WILL BRING POTENTIAL FOR A QUICK BOUT WITH LIGHT SNOW AGAIN WED NIGHT INTO EARLY THU. SYSTEM WON/T HAVE MUCH MOISTURE TO WORK WITH...SO MENTION OF SNOW WILL BE CONFINED MAINLY TO THE WESTERN/NORTHERN SECTIONS. CONTINUED HIGHEST POPS IN THE NW CLOSEST TO LAKE INFLUENCES...BUT BY THIS TIME THE FLOW VEERS BACK NEAR 270 DEGREES WHICH SHOULD PUSH HEAVIEST ACCUMS JUST NORTH OF PA BORDER. TEMPS COOL FURTHER WITH LOWS FROM 5 TO 15F AND HIGHS THU REMAINING IN THE TEENS ACROSS THE N AND W. HIGH PRESSURE EDGES IN FROM THE WEST LATER THU INTO SAT...BRINGING QUIETER BUT CHILLY WEATHER. TEMPS THU NIGHT WILL BE SIMILAR TO WED NIGHT...WITH A SLIGHT RECOVERY IN TEMPS FRI INTO FRI NIGHT. THIS WEEKEND...FLOW TURNS SOUTHWESTERLY BRINGING CONTINUED MODERATION TO TEMPERATURES. GFS COMING ON BOARD WITH ECMWF IN BRINGING ANOTHER WAVE OF LOW PRESSURE LATER SAT INTO SUNDAY. TEMPS SHOULD WARM ENOUGH TO BRING A RAIN/SNOW MIX ACROSS THE SE HALF...WITH CORE OF HEAVIEST PRECIP PROGGED TO REMAIN JUST SE OF THE CWA AT THIS TIME. ANOTHER SHOT OF COLD AIR SLIDES IN FOR EARLY NEXT WEEK. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... LOW CIGS/FOG PERSISTING EARLY THIS EVENING ACROSS EASTERN PA BENEATH TEMPERATURE INVERSION WITH LGT WINDS. A WEAK COLD FRONT...LOCATED ACROSS CENTRAL PA AT 23Z...WILL PUSH INTO EASTERN PA THIS EVENING. DOWNSLOPING WESTERLY FLOW BEHIND FRONT AND MIXING OF DRIER AIR ALOFT IS RESULTING IN CLEARING SKIES AT KIPT AS OF 23Z. HOWEVER...LATEST RAP AND SREF OUTPUT SUGGEST A MUCH MORE PESSIMISTIC OUTLOOK ACROSS SOUTHEAST PA...WITH LOW CIGS/FOG POTENTIALLY HANGING ON MUCH OF THE NIGHT AT KLNS. FORECAST UNCERTAINTY IS VERY HIGH IN THE NEAR TERM AT KMDT AND KLNS AND IS LINKED TO EXACTLY HOW FAR WEAKENING COLD FRONT AND DRY AIR MAKE IT INTO SE PA OVERNIGHT. ELSEWHERE...RESIDUAL LOW LVL MOISTURE FORCED TO ASCEND THE ALLEGHENY MTNS WILL LIKELY PRODUCE PERSISTENT MVFR STRATOCU OVERNIGHT AT KJST AND KBFD...WHILE ODDS FAVOR VFR CONDS FROM KAOO NE TO KIPT FOR MOST OF THE NIGHT. A FAST-MOVING LOW PRESSURE SYSTEM WILL TRACK SOUTH OF PA TUESDAY MORNING...SPREADING A PERIOD OF SNOW ACROSS MAINLY SOUTHERN PA BTWN 10Z-18Z. IFR VSBYS APPEAR LIKELY DURING LATE AM/EARLY AFTN AT KMDT AND KLNS. LIGHTER SNOW WILL FALL FURTHER NORTH. HOWEVER...A BRIEF DIP TO IFR VSBYS IS POSSIBLE ELSEWHERE TUE AM. IMPROVING CONDS ARE EXPECTED BY TUE AFTN AS THE LOW PRES SYSTEM PASSES OFF THE MID ATLANTIC COAST. OUTLOOK... WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS. THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS. FRI...NO SIG WX EXPECTED. SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 AM TO 4 PM EST TUESDAY FOR PAZ024>028-033>036-049>053-056>059-063>066. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...RXR AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1200 PM CST SUN DEC 8 2013 .DISCUSSION... SEE AVIATION FOR 18Z TAF ISSUANCE. && .AVIATION... MOSTLY MVFR CIGS TOWARDS THE SOUTH WITH IFR CONDITIONS IN OUR NORTHWESTERN PARTS OF THE CWA. NAM AND RAP ADVERTISING CLEARING FOR KCLL...KUTS...AND POSSIBLY KCXO TONIGHT WHILE GFS AND ECMWF HOLD UP THE CLEARING LINE. LOOKS LIKELY THAT SOME DRY AIR WILL WORK IN FROM THE WEST BUT SHOULD ONLY PUNCH FAR ENOUGH SOUTH TO CLEAR OUT MOST CLOUDS AT KCLL. SINCE NAM IS CLEARING OUT THE CLOUDS IT ALSO SUPPORTS THE FORMATION OF FOG TO THE NORTHERN TAF SITES. THIS IS SUPPORTED BY THE NAM DEWPOINT DEPRESSION FIELD. LIGHT WINDS FROM THE SURFACE HIGH PRESSURE WILL ALSO HELP PROMOTE FOG IN THE NORTHERN TAF SITES. STRONGER WINDS FURTHER SOUTHWARDS IN COMBINATION WITH CLOUD COVER SHOULD KEEP IT MOSTLY A STRATUS EVENT. 23 && .PREV DISCUSSION... /ISSUED 1028 AM CST SUN DEC 8 2013/ DISCUSSION... TEMPERATURES HAVE FINALLY CREPT ABOVE FREEZING NOW ALL ZONES WITH THE FREEZING LINE NOW JUST NORTHWEST OF OUR FORECAST AREA. SOME SPOTS FROM CENTERVILLE OUT TOWARD METROPLEX STILL SEEING FREEZING FOG BUT NOT EXPECTING ANY MORE ICY CONDITIONS IN THOSE NORTHWEST COUNTIES WHICH HAD THE ISSUES LAST NIGHT AND EARLY THIS MORNING. THEREFORE FREEZING FOG ADVISORY WILL BE ALLOWED TO EXPIRE. GOING FORWARD...TRICKY TEMP FORECAST TODAY AS VISIBLE SATELLITE SHOWING A FEW THIN SPOTS. AM FORECASTING HIGH TEMPERATURES A FEW DEGREES BELOW MOST GUIDANCE BASED ON THE IDEA WILL KEEP CLOUD COVER THROUGH THE AFTERNOON...WITH JUST BRIEF PERIODS OF BRIGHTENING FROM SOME FILTERED SUN. AMOUNT OF SUN WILL DETERMINE HIGH TEMPS...SO IF MORE THAN EXPECTED COULD EXCEED FORECAST TEMPS...BUT DONT THINK THAT WILL HAPPEN. WITH SIMILAR VERTICAL MOISTURE PROFILE...COULD STILL SEE SOME SPOTTY DRIZZLE OR SPRINKLES TODAY AS WEAK DISTRUBANCES RIPPLE ALONG IN FAST WSW FLOW ALOFT...BUT CHANCE OF MEASURABLE RAIN ONLY 20 PERCENT OR SO. PREV DISCUSSION... /ISSUED 438 AM CST SUN DEC 8 2013/ DISCUSSION... WENT AHEAD AND REPLACED WINTER WX ADVISORY WITH A FREEZING FOG ADVISORY AND EXTENDED IT UNTIL 10 AM. FIRST ONE I`VE ISSUED IN 19 YEARS HERE...BUT SEEMS TO FIT/DESCRIBE ONGOING CONDITIONS BEST. MODELS HAVE BEEN OVERDOING QPF AMOUNTS/COVERAGE AND FEEL THEY PROBABLY WILL AGAIN TODAY ESP AS RRQ OF JET SHOULD LIFT OUTS OF THE REGION. MAY STILL SEE A PATCHY AREA OF SPRINKLES/DRIZZLE ACROSS SE PARTS THIS AFTN BUT WENT AHEAD AND LOWERED POPS TO ~20%. REINFORCING FRONT STILL PENCILED IN TO MOVE THRU THE REGION ON MONDAY. ANOTHER ROUND OF ISENTROPIC LIFT FROM LATE AFTN MON-LATE TUE MORNING MAY BRING SOME MORE POCKETS OF DZ/-RA. WILL AGAIN NEED TO KEEP AN EYE ON SFC TEMP PROFILE ACROSS OUR EXTREME NRN COUNTIES DURING THIS TIME FRAME BUT FREEZING LINE DOESN`T LOOK TO MAKE IT NEARLY AS FAR SOUTH AS THE PAST FEW. P/MCLDY...COOL...MDRY DAYS SHOULD THEN PERSIST WED-THURS. COMBINATION OF COASTAL TROF AND SHORTWAVES EMBEDDED IN THE SW FLOW ALOFT SHOULD BRING INCREASED RAIN CHANCES THURS NIGHT AND INTO THE WEEKEND. 47 MARINE... LIGHT TO MODERATE OFFSHORE WINDS TO PREVAIL TODAY WITH HIGH PRESSURE SETTLING OVER THE STATE. MODELS STILL GOING WITH THE PASSAGE OF A RE- INFORCING COLD FRONT LATE TOMORROW. WINDS SHOULD PICK BACK UP TO SCA AND/OR SCEC CRITERIA STARTING BY LATE MON NIGHT/TUES. THESE ELEVATED WINDS/SEAS FCST TO PERSIST THROUGH WEDS (OR SO). THE STRONG SFC HIGH IN THE WAKE OF THIS COLD AIRMASS IS NOT EXPECTED TO MOVE EAST OF THE REGION UNTIL THE LATTER PART OF THE WEEK. AS SUCH WE MAY NOT SEE THE RETURN OF ONSHORE WINDS UNTIL SAT. 41 AVIATION... CIGS/VIS FALLING THIS MORNING WITH THE END OF THIS PCPN. WET GROUNDS AND NEARLY CALM WINDS TO HELP IN THE FORMATION OF LOW CLOUDS/FZFG ON THROUGH MID/LATE MORNING. HOWEVER STILL THINKING THAT MVFR CIGS WILL PREVAIL BY THIS AFTN. CIGS/VIS COULD FALL AGAIN TONIGHT ALONG WITH A RETURN OF LIGHT PCPN GIVEN THE PERSISTENT SWLY UPPER FLOW (AND POSSI- BILITY OF ADDITIONAL EMBEDDED SHORTWAVES MOVING ACROSS). REINFORCING SHOT OF COLD AIR EXPECTED MON NIGHT WITH WINDS INCREASING ONCE AGAIN INTO TUES. 41 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 42 36 47 34 42 / 10 10 30 30 20 HOUSTON (IAH) 44 42 53 40 44 / 10 20 30 30 20 GALVESTON (GLS) 49 47 55 46 50 / 20 20 30 30 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...99 AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1254 PM EST SUN DEC 8 2013 .SYNOPSIS... ARCTIC HIGH PRESSURE TO OUR NORTH WILL PROVIDE A CONTINUOUS SOURCE OF COLD AIR TODAY. A TROUGH OF LOW PRESSURE DEVELOPING OVER THE TENNESSEE RIVER VALLEY WILL PROVIDE A CONTINUOUS SOURCE OF MOISTURE. THE COLD AIR WILL INTERACT WITH MOISTURE FOR A BLEND OF WINTRY PRECIPITATION ACROSS THE REGION TODAY AND TONIGHT. FREEZING RAIN WILL BE THE DOMINANT PRECIPITATION TYPE. && .NEAR TERM /THROUGH TONIGHT/... AS 1232 PM EST SUNDAY... ADDED SOME FREEZING DRIZZLE AND FOG TO ISC GRIDS FOR THIS AFTERNOON INTO TONIGHT. TEMPERATURES CONTINUE TO DROP AS A WEDGE OF COLD AIR PUSHES DOWN THE APPALACHIANS. WINTER MIX OF SNOW...SLEET AND FREEZING DRIZZLE AND FREEZING RAIN WILL TRANSITION TO FREEZING RAIN/RAIN FOR MOST OF THE FORECAST TONIGHT. LATEST RADAR TRENDS LINE UP NICELY WITH HRRR SOLUTION FOR THIS AFTERNOON. ADJUSTED TEMPERATURES...WEATHER...POPS AND AMOUNTS FOR THE NEXT COUPLE OF HOURS. AS OF 944 AM EST SUNDAY... WINTER STORM WARNINGS REMAIN IN EFFECT INTO MONDAY MORNING FOR MOST OF CWA WITH A COMPLEX WINTER STORM MARCHING ACROSS OUR REGION TODAY WITH A MIXTURE OF SNOW...SLEET...FREEZING RAIN AND RAIN. TROUGH OF LOW PRESSURE OVER THE TENNESSEE RIVER VALLEY WILL STRENGTHEN THIS AFTERNOON...PROVIDING A CONTINUOUS SOURCE OF MOISTURE. HIGH PRESSURE LOCATED ACROSS PENNSYLVANIA IS BUILDING INTO THE AREA FROM THE NORTH...PROVIDING A SOURCE OF COLD AIR. THE WEDGE OF COLD AIR ON THE EAST SIDE OF THE MOUNTAINS WILL LIKELY REMAIN IN PLACE THROUGH TONIGHT. SNOW AND SLEET REPORTED ACROSS THE NORTH GENERALLY SOUTHEAST WEST VIRGINIA AND ALLEGHANY HIGHLANDS. POCKETS OF SLEET AND FREEZING RAIN FALLING ACROSS LARGE PORTION OF CWA THIS MORNING. REPORTS OF UP TO A TENTH OF AN INCH OF ICE THIS MORNING. RAIN AND EVEN ELEVATED CONVECTION REPORTED THIS MORNING ACROSS THE SOUTH. STILL LOOKS LIKE MOST OF THE REGION WILL TRANSITION TO FREEZING RAIN THIS AFTERNOON INTO TONIGHT. HIGHEST ICE AMOUNTS EXPECTED ALONG THE SOUTHERN BLUE RIDGE. UPDATED ISC GRIDS TO MATCH UP WITH CURRENT WEATHER...TEMPERATURES AND RADAR IMAGES. MORE ADJUSTMENTS LATER THIS MORNING.... WE WILL BE LAUNCHING A 18Z SOUNDING. AS OF 500 AM EST SUNDAY... ALL INGREDIENTS ARE IN PLACE FOR WINTRY PRECIPITATION TODAY. SURFACE HIGH PRESSURE IS STILL BUILDING INTO THE AREA FROM THE NORTHEAST. THIS WILL PROVIDE A CONTINUOUS SOURCE OF COLD AIR TODAY...TEMPERATURES CONTINUING TO FALL THROUGH THE MORNING HOURS. MOST LOCATIONS SHOULD WETBULB AT OR BELOW FREEZING THIS MORNING. SOME AREAS ARE ALREADY WELL BELOW FREEZING...NOTING THE 21 DEG F TEMP AT HSP AIRPORT AS OF 5AM. TROUGH OF LOW PRESSURE OVER THE TENNESSEE RIVER VALLEY WILL STRENGTHEN TODAY...PROVIDING A CONTINUOUS SOURCE OF MOISTURE. ALL MODELS INDICATE STRONG ISENTROPIC LIFT ACROSS THE AREA WITH INCREASING MID LEVEL FRONTOGENESIS. THIS SHOULD YIELD WIDESPREAD DEVELOPMENT OF PRECIPITATION...QPF OF A QUARTER TO THREE QUARTERS OF AN INCH...FROM 12Z/7AM THIS MORNING THROUGH 12Z/7AM MONDAY MORNING. THIS WILL TRANSLATE INTO AN ACCUMULATION OF SIGNIFICANT WINTRY PRECIPITATION...THE DOMINANT P-TYPE...FREEZING RAIN. WARM INTRUSION ALOFT CAPS THE COLD BOUNDARY LAYER. VERY WARM AIR...4-8 DEG C...IS MOVING NORTHEAST THROUGH THE TENNESSEE VALLEY AND WILL FLOW UP AND OVERTOP THE COLD AIR WEDGE HERE ON THE EAST SIDE OF THE APPALACHIAN MOUNTAINS. THIS SHOULD ENSURE THAT MOST... IF NOT ALL...HYDROMETEORS MELT ON THERE WAY TO THE SURFACE. THE ONLY AREA WHERE THE SOUNDING PROFILE MAY ENTERTAIN ISOTHERMAL CHARACTERISTICS...THE WARM NOSE CLOSER TO 0 DEG C...IS FROM THE HIGHLANDS OF VA/WV NORTHEASTWARD INTO THE SHENANDOAH VALLEY. AS SUCH...THE PRECIPITATION MAY TAKE ON THE FORM OF SLEET AND SNOW WHICH COULD ACCUMULATE AN INCH OR TWO THIS MORNING. BY AFTERNOON...THE WARM INTRUSION SHOULD MAKE ITS WAY FAR ENOUGH NORTH LATITUDE TO CHANGE THE PRECIP TO FREEZING RAIN THERE TOO. THE WEDGE OF COLD AIR ON THE EAST SIDE OF THE MOUNTAINS WILL LIKELY REMAIN IN PLACE THROUGH TONIGHT. GIVEN THE EXTENT OF WARMING WHICH IS FORECAST TO TAKE PLACE ALOFT...SOME OF THE MODELS INDICATING AS WARM AS +10 DEG C AT 85H...MODIFICATION OF THE COLD BOUNDARY LAYER SEEMS INEVITABLE...AND SHOULD RESULTING IN STEADILY RISING TEMPERATURES AT THE SURFACE. A GRADUAL CHANGE FROM FREEZING RAIN TO JUST PLAIN OL RAIN IS ANTICIPATED...ESP WEST OF THE APPALACHIAN DIVIDE. WITH THE INCREASED WARMING ALOFT...FOG WILL LIKELY BECOME AN ISSUE AS THE WARMER AIR MIXES WITH THE COLD MOIST BOUNDARY LAYER. GREATEST ACCUMULATIONS OF ICE TODAY/TONIGHT ARE EXPECTED ALONG THE SPINE OF THE BLUE RIDGE WHICH WILL RESIDE IN THE COLDER AIR THE LONGEST...AND WHERE THE LOW LEVEL UPSLOPE EASTERLY WIND FLOW WILL ENHANCE THE LOCAL QPF/ICING AMOUNTS. HIGHEST IMPACT FROM THIS EVENT WILL BE ICING ON ELEVATED SURFACES. THE GROUND IS STILL RELATIVELY WARM FROM THIS PAST WEEKS WARMTH...SO THEORETICALLY THERE SHOULD BE LESS OF AN IMPACT TO ROAD SURFACES. THAT BEING SAID...ITS STILL A GOOD DAY TO SIT THIS ONE OUT. THE ROADS CAN FOOL YOU ONCE THE AIR TEMP REMAINS BELOW FREEZING LONG ENOUGH. UNTREATED SURFACES MAY LOOK WET...BUT MAY ACTUALLY CONTAIN A THIN COATING OF ICE HIDDEN BY WHAT APPEARS TO BE JUST WET PAVEMENT. IF VENTURING OUT OF DOORS...PREP ACCORDINGLY. A COLD RAIN OR FREEZING RAIN MAKES FOR IDEAL HYPOTHERMIC CONDITIONS. WALKING OUT TO CHECK THE ICE ACCUMULATION ON MY VEHICLE WAS ENOUGH TO MAKE MY TEETH CHATTER...AS THE OLD SAYING GOES...THE DAMPNESS IN THE AIR WILL CUT RIGHT THROUGH YA...A COLD RAW RAIN. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... AS OF 500 AM EST SUNDAY... FOR THE MONDAY MORNING COMMUTE...MAY SEE A FEW POCKETS OF FREEZING RAIN LEFT OVER ACROSS THE SHENANDOAH VALLEY...BUT OTHERWISE EXPECT TEMPERATURES TO BE WARM ENOUGH ALL OTHER LOCATIONS FOR PRECIPITATION TO FALL AS LIQUID. ANY ICING LEFTOVER FROM THE OVERNIGHT SHOULD MELT QUICKLY DURING LATE MORNING AS TEMPERATURES CLIMB INTO THE MID 40S NORTH OF INTERSTATE 81...AND INTO THE LOW 50S FURTHER SOUTH. DURING MID AFTERNOON...EXPECT RAIN TO BECOME MORE SHOWERY IN NATURE AS A COLD FRONT MAKES ITS WAY EAST ACROSS THE AREA. AS WINDS SHIFT NORTHWESTERLY BEHIND THE FRONT...WILL SEE SHOWERS DIMINISH IN COVERAGE FOR THE EVENING...ALTHOUGH THE BREAK WILL BE SHORT-LIVED. PACIFIC HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT MONDAY NIGHT...AND WILL BUILD SOUTHWARD AGAINST THE EASTERN FACE OF THE APPALACHIANS BUY TUESDAY MORNING...RESULTING IN A COOL NORTHEASTERLY WINDFLOW ACROSS THE AREA. MEANWHILE...OUR NEXT UPPER LEVEL TROUGH WILL PASS ACROSS THE PLAINS...DRAWING ANOTHER WAVE OF WARM GULF MOISTURE NORTHWARD ALONG THE APPALACHIAN CHAIN. RAIN ASSOCIATED WITH THE TROUGH WILL COVER MUCH OF THE AREA DURING THE MORNING...BUT DO NOT ANTICIPATE WIDESPREAD WINTRY PRECIPITATION ISSUES AS THE PACIFIC HIGH PRESSURE SYSTEM HUGGING THE SURFACE WILL BE WARMER THAN THE HIGH WHICH CONTRIBUTED TO FREEZING PRECIPITATION THIS PAST WEEKEND. REGARDLESS...EXPECT TEMPERATURES TO REBOUND LITTLE...IF ANY...FROM OVERNIGHT LOWS DUE TO THE RAIN...WITH AFTERNOON HIGHS RANGING FROM AROUND FREEZING IN SOUTHEAST WEST VIRGINIA...TO THE LOW 40S ACROSS NORTHERN NORTH CAROLINA. THE UPPER LEVEL TROUGH WILL PASS EAST OF OUR AREA TUESDAY NIGHT... TAKING REMAINING PRECIPITATION WITH IT FOR THE MOST PART...ALTHOUGH A FEW UPSLOPE SNOW SHOWERS MAY LINGER ACROSS SOUTHEAST WEST VIRGINIA INTO LATE EVENING. HIGH PRESSURE WILL BUILD IN FROM THE WEST... BRINGING A RETURN OF SOME SUNSHINE FOR WEDNESDAY. && .LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 310 PM EST SATURDAY... SURFACE HIGH PRESSURE REMAINS OVER MUCH OF THE EASTERN UNITED STATES THURSDAY AND FRIDAY WHICH WILL KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL. WEAK NORTHERN STREAM SHORTWAVE COMING THROUGH EARLY THURSDAY...BUT MODELS KEEP FORECAST AREA DRY. NEXT ORGANIZED SYSTEM COMES OUT OF SOUTHERN STREAM FRIDAY NIGHT THROUGH SATURDAY. THIS TIMING LEANS TOWARD SLOWER ECMWF. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 1254 PM EST SUNDAY... ICE AND LOW CEILINGS WILL HINDER AVIATION OPERATIONS THIS AFTERNOON INTO MONDAY. VERY HIGH CONFIDENCE FOR SEVERE CLEAR ICING AT ALL TAF SITES TODAY...WITH ONE QUARTER TO ONE HALF INCH ICE ACCUMULATIONS POSSIBLE. WINTRY MIXTURE OF SNOW...SLEET...FREEZING DRIZZLE AND FREEZING RAIN WILL CONTINUE INTO THIS EVENING...THEN PRECIPIATION WILL BECOME FREEZING RAIN AND RAIN TONIGHT INTO MONDAY MORNING. ACROSS THE NORTH...WHERE COLDER AIR IN PLACE CLOSER TO LWB...SNOW/ICE PELLETS WILL TRANSITION TO FREEZING RAIN. IFR CONDITIONS ARE EXPECTED WITH THE WINTER PRECIPITATION AT THE TAF SITES. EXPECT ALL AIRPORTS TO EXPERIENCE CEILINGS IN THE 300 TO 700 FOOT RANGE THIS AFTERNOON...WITH THESE LOW CEILINGS EXPECTED TO LAST INTO MONDAY. VISIBILITIES WILL ALSO BE UP AND DOWN AS HEAVIER PRECIPITATION MOVES ON AND OFF STATION. WARMER AIR WILL BUILD INTO THE AREA TONIGHT...RAISING SURFACE TEMPERATURES AND ENDING SEVERE CLEAR ICING FROM SOUTHWEST TO NORTHEAST. SUBFREEZING AIR WILL LINGER LONGEST AT LYH...WHICH MAY NOT SEE FREEZING PRECIPITATION END UNTIL 09/12Z TO 09/14Z. MEDIUM TO HIGH CONFIDENCE ON CEILINGS AND VISIBILITIES. HIGH CONFIDENCE IN WINDS DURING THE TAF PERIOD. .AVIATION EXTENDED... WEATHER WILL BE QUITE UNSETTLED THROUGH THE FIRST PART OF THE WEEK. A COLD FRONT WILL MOVE THROUGH ON MONDAY...BRINGING IMPROVED FLYING CONDITIONS AND A SHORT BREAK IN PRECIPITATION AS HIGH PRESSURE BUILDS IN FROM THE WEST. RAIN...IN ADDITION TO MVFR/IFR... WILL RETURN MONDAY NIGHT THROUGH TUESDAY MORNING AS AN UPPER TROUGH MOVES ACROSS THE REGION. HIGH PRESSURE WILL BUILD IN FOR WEDNESDAY AND THURSDAY WITH A RETURN TO VFR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER STORM WARNING UNTIL 9 AM EST MONDAY FOR VAZ011-013-014- 017>020-022>024-033>035-045>047. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ010-012- 015-016. WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR VAZ032-043-044- 058-059. FREEZING RAIN ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007- 009. NC...WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-002- 018. WINTER STORM WARNING UNTIL 4 AM EST MONDAY FOR NCZ003>006-019- 020. WV...WINTER STORM WARNING UNTIL 9 AM EST MONDAY FOR WVZ043>045. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ042. && $$ SYNOPSIS...PM NEAR TERM...KK/PM SHORT TERM...NF LONG TERM...AMS AVIATION...KK/NF
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
600 PM CST MON DEC 9 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 247 PM CST MON DEC 9 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A BROAD AREA OF LOW PRESSURE MOVING NORTHEAST OVER NORTHERN ONTARIO AND A SURFACE RIDGE AXIS SHIFTING EAST OVER THE NORTHERN PLAINS. BETWEEN THE TWO SYSTEMS...WEST WINDS IS DRIVING ARCTIC AIR ACROSS THE STATE...AND TEMPERATURES ARE DROPPING ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. NO CHANGE IN THE START OF TIME OF WIND CHILL HEADLINES...AS THEY ARE ALREADY APPROACHING CRITERIA AT RHINELANDER. THE LEADING EDGE OF THIS ARCTIC AIR IS MARKED BY A BAND OF STRATO-CU AND ACCOMPANYING LIGHT SNOW SHOWERS/FLURRIES...WHICH IS NOW ENTERING NORTHEAST WISCONSIN. ANTICIPATE THE SNOW SHOWERS/FLURRIES TO DIMINISH LATER THIS AFTERNOON ONCE THE SUN GOES DOWN AND ANY DIURNAL INSTABILITY IS LOST. ATTENTION THEN TURNS TO A FAST MOVING CLIPPER SYSTEM WHICH IS DIVING SE OVER SOUTHERN SASKATCHEWAN THIS AFTERNOON. THE CLIPPER LOOKS DECENT ON SATELLITE IMAGERY AND THERE ARE PLENTY OF OBS OVER WESTERN NORTH DAKOTA AND EASTERN MONTANA SHOWING LIGHT TO MODERATE SNOW. SO THE FORECAST CONCERNS START OUT WITH WIND CHILLS TONIGHT...AND SNOW POTENTIAL WITH THE CLIPPER LATE TONIGHT INTO TUESDAY MORNING. TONIGHT...HIGH PRESSURE RIDGE AXIS WILL MOVE EAST INTO CENTRAL WISCONSIN THIS EVENING AND ACROSS EASTERN WISCONSIN OVERNIGHT. ALONG WITH THE LOSS OF DAYTIME HEATING...THIS WILL HELP SKIES CLEAR AND LIGHT SNOW/FLURRIES COME TO AN END LATE IN THE AFTERNOON OR EARLY THIS EVENING. ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION DURING THE EVENING...AND THE CLEARING SKIES WILL PROMOTE TEMPS FALLING QUICKLY WITH LOWS OCCURRING NEAR OR SHORTLY AFTER MIDNIGHT. THEN ALL EYES WILL BE ON A FAST MOVING CLIPPER PROGGED TO ENTER THE STATE LATE TONIGHT. THE LATEST MODEL RUNS HAVE TRENDED A FEW HOURS SLOWER...AND NOW START BRINGING IT INTO THE STATE AFTER 09Z. THE VORT WILL BRING EXCELLENT MID-LEVEL FORCING...SO WILL INCREASE POPS BY 12Z DESPITE A SEVERE LACK OF MOISTURE. WITH THE LATER ARRIVAL OF THE CLIPPER...WIND CHILL READINGS WILL REMAIN NEAR THE 20 BELOW CRITERIA OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE 12Z HOUR SO NO CHANGE IN HEADLINES ANTICIPATED. TEMPS WILL REBOUND SOMEWHAT WITH THE INCREASING CLOUDS OVERNIGHT. TUESDAY...THE CLIPPER WILL QUICKLY ADVANCE EAST ACROSS THE AREA TUESDAY MORNING. THE STRONG FORCING AND POCKET OF INSTABILITY IN THE MID-LEVELS SHOULD BRING A FEW TENTHS OF DRY FLUFFY SNOW ACROSS THE ENTIRE FORECAST AREA BEFORE IT RAPIDLY PULLS OUT BY LATE IN THE MORNING OR EARLY AFTERNOON. ANOTHER SURGE OF ARCTIC AIR WILL FOLLOW IN THE WAKE OF THE CLIPPER...WITH STEEPENING LOW LEVEL LAPSE RATES AND ENHANCED LOW LEVEL RH. WOULDNT BE SURPRISED TO SEE INSTABILITY SNOW SHOWERS/FLURRIES REDEVELOP IN THE AFTERNOON...SIMILAR TO THE SNOW SHOWERS ONGOING TODAY. WILL LET THE NEXT SHIFT EVALUATE BEFORE ADDING THEM TO THE FORECAST. HIGHS FROM THE MIDDLE SINGLE DIGITS NORTH TO THE MIDDLE TEENS EAST. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 247 PM CST MON DEC 9 2013 COLD TEMPERATURES/WIND CHILLS AND PCPN CHANCES ARE THE MAIN FCST CONCERNS. A REINFORCING SHOT OF ARCTIC AIR WILL BE IN PLACE TUES NGT INTO WEDS...WITH H8 TEMPS OF -20 TO -25 C OVER THE FORECAST AREA. LOW- LEVEL WINDS WILL BE WEST-NORTHWEST...SO LAKE EFFECT IMPACT WILL BE MINIMAL...WITH JUST A FEW SNOW SHOWERS OR FLURRIES EXPECTED OVER VILAS COUNTY. A S/W TROF AND THE RRQ OF A JET STREAK WILL QUICKLY SWEEP THROUGH THE SOUTHERN PART OF GRB CWA ON TUES NGT...SO KEPT CHC POPS OVER C/EC WI. CLOUDS ASSOCIATED WITH THIS SYSTEM AND ANY LAKE-INDUCED CLOUDS OVER THE FAR NORTH COULD HAVE A BIG IMPACT ON MIN TEMPS. USED A BLEND OF THE PREV FCST...ECMWF AND A FEW OTHER TOP PERFORMING GUIDANCE SETS...AND MADE A FEW TWEEKS TO ACCOUNT FOR CLOUD TRENDS. WILL HAVE COLDEST MIN TEMPS (-15 TO -17 F) IN THE TOMAHAWK/RHINELANDER/CRANDON REGION...WITH SINGLE DIGITS BELOW ZERO OVER OUR SOUTHERN/EASTERN COUNTIES...EXCEPT SINGLE DIGITS ABOVE ZERO ALONG THE LKSHR. HIGH TEMPS ON WEDS WILL BE IN THE 5 BELOW TO 5 ABOVE RANGE IN MOST AREAS...COLDEST OVER NC WI. WIND CHILLS LOOK LIKE THEY WILL DROP INTO THE -20 TO -30 RANGE NORTHWEST OF A LINE FROM ISW-IMT TUES NGT INTO WEDS...AND OVER MOST OF THE CWA ON WED NGT...SO ADDITIONAL WIND CHILL ADVISORIES MAY BE NEEDED. WAA WILL DEVELOP LATE WEDS NGT INTO THURSDAY...AND WILL PROBABLY GENERATE SOME LIGHT SNOW OR FLURRIES. SOME MODERATION IN TEMPS IS ANTICIPATED...WITH HIGHS REACHING THE UPPER SINGLE DIGITS AND TEENS. THE ARCTIC BAROCLINIC ZONE WILL RESIDE OVER THE REGION THROUGH MUCH...IF NOT ALL...OF THE EXTENDED FORECAST. TEMPERATURES WILL REMAIN BLO NORMAL. WITH STRONG WEST-NORTHWEST FLOW ALOFT IN PLACE DURING THE PERIOD...SEVERAL JET STREAKS/SHORT-WAVE TROFS WILL PASS THROUGH THE GREAT LAKES REGION. THE RRQ OF A JET STREAK WILL PASS THROUGH THE REGION THU NGT AND FRI...AND MODELS ARE HINTING AT AN INVERTED SFC TROF AFFECTING THE REGION FRI NGT/SAT... AND POSSIBLY LINGERING OVER THE RGN INTO SUNDAY. ANY OF THESE DISTURBANCES COULD PRODUCE LIGHT SNOW OR FLURRIES...SO ALMOST EVERY PERIOD OF THE FCST HAS SLGT CHC/CHC POPS. HOPEFULLY IN THE NEXT FEW DAYS WE WILL BE ABLE TO BETTER DEFINE WHICH OF THESE SYSTEMS WILL HAVE THE MOST IMPACT ACROSS THE REGION. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 545 PM CST MON DEC 9 2013 RIDGE OF HIGH PRESSURE WILL SLIDE OVER THE REGION THIS EVENING TO PRODUCE DIMINISHING WINDS AND VFR CONDITIONS. AFTER MIDNIGHT MID TO HIGH LEVEL CLOUDS WILL MOVE INTO THE THE AREA AS A CLIPPER SYSTEM APPROACHES THE STATE. AS THE CLIPPER TRACKS OVER NORTHERN WISCONSIN TUESDAY MORNING...A PERIOD OF MVFR CIGS WITH PERHAPS A 2 HOUR PERIOD IFR CIGS DUE TO SNOW SHOWERS AND BLSN MAY BE ASSOCIATED WITH ANOTHER ARCTIC COLD FRONT PASSAGE. GUSTY WEST WINDS WITH AREAS OF BLSN WILL THEN CONTINUE FOR THE REST OF TUESDAY BEFORE DIMINISHING LATE IN THE DAY FROM WEST TO EAST ALONG WITH IMPROVING CIGS TO VFR CONDITIONS. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ005-010>013- 018>021-030-031-035>037. && $$ SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND MONDAY ISSUED AT 232 PM CST SUN DEC 8 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ONE SHORTWAVE TROUGH MOVING INTO SOUTHWEST WISCONSIN THIS AFTERNOON...WHILE ANOTHER WAVE NOW ENTERING THE CENTRAL GREAT PLAINS. AHEAD OF THE FORMER SHORTWAVE...WEAK ISENTROPIC ASCENT IS PRODUCING A WIDESPREAD SWATH OF LIGHT SNOW ACROSS THE STATE. THE BETTER SNOWS WITH THE FIRST WAVE ARE STILL ACROSS IOWA AT THE MOMENT...WHERE VSBYS ARE DOWN TO A HALF MILE AND WIDESPREAD 1-2 INCHES ARE BEING REPORTED SO FAR. FURTHER CONCERNS RESIDE ALONG THE LAKE SHORE WHERE LAKE ENHANCEMENT IS OCCURRING OVER CENTRAL AND SOUTHERN PARTS OF THE LAKE MICHIGAN SHORELINE. EARLIER REPORTS SHOWED 1-1.5 INCH PER HOUR SNOWFALL RATES IN THOSE LAKE ENHANCED BANDS. ONE OF THESE BANDS IS APPROACHING MANITOWOC...BUT APPEARS TRANSIENT IN A LOW LEVEL CONVERGENT ZONE. LOW LEVEL WINDS ARE JUST STARTING TO TURN TO THE SOUTHEAST SO WILL NEED TO WATCH THESE TRENDS FOR THE REST OF THE AFTERNOON. AS THE SHORTWAVES MOVE ACROSS THE ARE TONIGHT...SNOWFALL AMOUNTS AND IMPACTS ARE THE MAIN FORECAST CONCERN. TONIGHT...SHORTWAVE TROUGH OVER COLORADO WILL QUICKLY EJECT NORTHEAST A DRIVE A STRENGTHENING...ALTHOUGH STILL RELATIVELY WEAK...AREA OF LOW PRESSURE FROM THE CENTRAL GREAT PLAINS AND ACROSS SOUTHEAST WISCONSIN TONIGHT. FORCING AHEAD OF THE SHORTWAVE IN THE FORM OF -DIVQ...UPPER DIVERGENCE...AND ISENTROPIC ASCENT IS ONLY MODEST...BUT BUFKIT SOUNDINGS FROM THE NAM/GFS/SREF ALL INDICATE A 150-200MB DEEP DENDRITIC GROWTH ZONE BETWEEN APPROX 850-650MB OVER CENTRAL AND NORTHEAST WISCONSIN. THIS SUGGESTS THAT WHATEVER WEAK TO MODERATE LIFT THAT OCCURS...SNOW FLAKE PRODUCTION WILL BE VERY EFFICIENT AND SNOW TO LIQUID RATIOS WILL BE QUITE HIGH. GENERALLY WENT WITH A 19-20:1 RATIO...ALTHOUGH A LITTLE LOWER NEAR THE LAKE MICHIGAN SHORELINE WHERE ONSHORE FLOW WILL LEAD TO SLIGHTLY WARMER LOW LEVEL THERMAL PROFILES. THE BULK OF THE SNOW LOOKS TO OCCUR IN A COUPLE WAVES. THE FIRST WILL ARRIVE LATE THIS AFTERNOON INTO EARLY THIS EVENING FROM THE FIRST AREA OF SNOW OVER IOWA AND SE MINNESOTA...FOLLOW BY THE MAIN SHORTWAVE AND SURFACE LOW OVER COLORADO. PLENTY OF 1-3" INCH REPORTS UPSTREAM OVER IOWA...AND FEW 4-6 INCH REPORTS OVER EASTERN NEBRASKA AS WELL. WILL INCREASE AMOUNTS A LITTLE OVER N-C WISCONSIN TO AROUND 3 INCHES. THE PRIMARY CONCERN THOUGH WILL BE ALONG THE LAKE SHORE WHERE WINDS WILL BE TURNING TO THE EAST AND SOUTHEAST THIS EVENING. THE LAKE ENHANCEMENT OVER SOUTHEAST WISCONSIN APPEARS TO BE FLUCTUATING...AS A CONVERGENT BAND LIFTS NORTH. BUT EARLIER SNOWFALL RATES WHERE ENHANCEMENT TOOK PLACE ARE ALARMING. LOOKS LIKE A GOOD 9-12 HOURS OF ENHANCEMENT POSSIBLE OVER NORTHEAST WISCONSIN. WILL GO WITH WIDESPREAD 2-4 INCHES EXCEPT NEAR THE LAKESHORE WHERE 5-6 INCHES WILL BE POSSIBLE. HEADLINES WILL REMAIN THE SAME...AND WILL PASS ALONG LAKE ENHANCEMENT CONCERNS TO THE EVENING SHIFT. MONDAY...THE SNOW WILL BE ENDING EARLY MONDAY MORNING OVER NORTHEAST WISCONSIN AS THE SURFACE LOW PULLS AWAY. WEST WINDS WILL BE STRENGTHENING IN THE WAKE OF THE LOW AND COLD ADVECTING AT THE SAME TIME. TEMPS WILL REMAIN NEARLY STEADY OR FALL SLIGHTLY DURING THE DAY...DESPITE CLEARING TAKING PLACE. WITH WINDS GUSTING TO 30 MPH...APPARENT TEMPS WILL BE FALLING TO NEAR 20 BELOW ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. WILL LIKELY NEED WIND CHILL HEADLINES...BUT WITH THE ONGOING SNOW ADVISORY...WILL NOT ISSUE ANOTHER HEADLINE. MORNING TO MIDDAY HIGHS IN THE MIDDLE SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR THE LAKE SHORE. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 232 PM CST SUN DEC 8 2013 VERY COLD AIR WILL REMAIN FIRMLY ENTRENCHED ACROSS THE AREA MONDAY NIGHT. EXPECT WINDS CHILLS TO DROP TO AROUND 25 BELOW ACROSS THE NORTH. HOWEVER...TEMPERATURES ARE EXPECTED TO MODIFY SOME LATE MONDAY NIGHT DUE TO INCREASING CLOUDINESS AND AHEAD OF APPROACHING SYSTEM. INCREASED CHANCES OF SNOW ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. INCREASED SNOW CHANCES SIGNIFICANTLY ON TUESDAY MORNING AS SYSTEM MOVES ACROSS THE AREA. ALSO...PRECIPITATION TOTALS WILL BE LIGHT...SNOW RATIOS WOULD SUGGEST LESS THAN AN INCH OF NEW SNOW TUESDAY MORNING. THE HIGHEST SNOWFALL TOTALS WILL BE ACROSS THE NORTH. MOST OF THE MODELS NOW BRING CLIPPER SYSTEM SOUTH OF THE AREA TUESDAY NIGHT. THE ONLY EXCEPTION WAS THE ECMWF...THUS WILL CONTINUE CHANCES ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. THE GFS MODELS HAS BEEN WAFFLING ON NORTHWARD EXTENT OF THE PRECIPITATION FIELD. VERY COLD AIR IS EXPECTED WEDNESDAY MORNING. ANOTHER SYSTEM EXPECTED TO PASS ACROSS THE NORTH THURSDAY/THURSDAY NIGHT. LOW CONFIDENCE ON WHEN THIS SYSTEM WOULD BRING A SMALL CHANCE OF LIGHT SNOW DURING THIS PERIOD. CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST THURSDAY NIGHT...BUT LATER SHIFTS MAY NEED TO SPEED UP THE SNOW AND ADD A CHANCE TO THE THURSDAY PERIOD. THE ARCTIC AIR WILL MODIFY FRIDAY INTO NEXT WEEKEND WITH HIGHS IN THE UPPER TEENS TO MIDDLE 20S. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1131 AM CST SUN DEC 8 2013 LOW PRESSURE WILL MOVE NORTHEAST THIS AFTERNOON ACROSS THE PLAINS AND THE CENTRAL GREAT LAKES TONIGHT. AHEAD OF THIS LOW...LIGHT SNOW WILL CONTINUE THIS AFTERNOON WHICH WILL DROP VSBYS TO IFR. THE SNOW WILL INCREASE IN INTENSITY THIS EVENING WHICH WILL DROP VSBYS TO LIFR...MAINLY OVER CENTRAL AND NORTHEAST WISCONSIN. LOCALLY VLIFR IN MODERATE TO HEAVY SNOW IS POSSIBLE ALONG THE LAKE MICHIGAN SHORELINE DUE TO LAKE ENHANCEMENT. THE SNOW WILL GRADUALLY DIMINISH OVERNIGHT TONIGHT...BUT WEST WINDS WILL DEVELOP BEHIND THE SYSTEM AND BECOME GUSTY BY MORNING. THE GUSTY WEST WINDS WILL LIKELY CREATE BLOWING AND DRIFTING OF THE NEW SNOW BY MIDDAY MONDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ005-010-011- 018>021-030-031-035>040-045-048>050-074. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ012-013-022- 073. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
132 AM CST SUN DEC 8 2013 .UPDATE... ISSUED AT 132 AM CST SUN DEC 8 2013 LIGHT SNOW IS RAPIDLY DEVELOPING AND/OR SPREADING INTO LOCATIONS ALONG/WEST OF THE MISSISSIPPI RIVER. IN FACT...EVEN HERE AT OUR OFFICE BEGINNING TO SEE SOME VERY SMALL FLAKES FALL. HAVE UPDATED THE FORECAST TO SPREAD PRECIPITATION CHANCES QUICKER INTO THE AREA. APPEARS MUCH OF THE SNOW DURING THE EARLY MORNING HOURS WILL BE LIGHT...LIKELY WITH VISIBILITIES ON THE ORDER OF 2 MILES. WSW ALSO UPDATED TO RELAY THE SNOW STARTING UP QUICKER. RAP SEEMS TO HAVE A GOOD HANDLE ON THE SITUATION THUS FAR. AVIATION DISCUSSION UPDATED BELOW AS WELL TO ACCOUNT FOR THE QUICKER START UP OF THE SNOW. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 206 PM CST SAT DEC 7 2013 FORECAST FOCUS IS ON SNOW POTENTIAL LATE TONIGHT THROUGH SUNDAY WITH SEVERAL INCHES OF LIGHT FLUFF ANTICIPATED TO ACCUMULATE. 20Z SURFACE ANALYSIS SHOWS ARCTIC HIGH PRESSURE ENTRENCHED ACROSS THE CENTRAL PART OF THE COUNTRY...WITH CHILLY TEMPS AND VERY LITTLE IN THE WAY OF CLOUD COVER. BUT THIS IS EXPECTED TO CHANGE AS A TROUGH OUT ACROSS THE INTERMOUNTAIN WEST MOVES QUICKLY INTO OUR AREA BY SUNDAY AFTERNOON. WITH SUCH COLD AIR IN PLACE...AS THE RELATIVELY WARMER AND MORE MOIST AIR MOVES NORTHWARD AHEAD THE SYSTEM...SEVERAL HOURS OF LIGHT FLUFFY SNOW WILL OCCUR. SATELLITE SHOWS HIGH CLOUDS ALREADY STREAMING INTO IA AHEAD OF THE SYSTEM... WITH THICKENING CLOUDS THROUGH THE NIGHT TONIGHT. MODELS HAVE BEEN INSISTING THAT THE FIRST WAA/ISENTROPIC UPGLIDE SNOW WILL BEGIN ACROSS WESTERN IA AND SOUTHERN MN BY 12Z...BUT IT WILL BE FIGHTING VERY DRY AIR INITIALLY. MODEL SOUNDINGS SHOW THE DOWNWARD SATURATION WITH TIME. FEEL LIGHT ACCUMULATION WILL BE POSSIBLE OVER SOUTHEAST MN AND NORTH CENTRAL IA ALREADY BEFORE SUNRISE...WITH SNOW QUICKLY OVERSPREADING THE REMAINDER OF THE AREA DURING THE MORNING. DRY AIR WILL BE THE MOST STUBBORN OVER SOUTHERN WI WITH THE EASTERLY FLOW AROUND THE DEPARTING SURFACE HIGH. WITH THIS SCENARIO AND IN AN EFFORT TO COORDINATE WITH SURROUNDING OFFICES...HAVE STAGGERED THE START TIMES OF THE WINTER WEATHER ADVISORY. SNOW RATIO SHOULD BE IN THE 17:1 TO 20:1 RANGE...SO IT WILL NOT TAKE MUCH LIQUID TO GENERATE A GOOD DEAL OF SNOW. SNOW SHOULD BE TAPERING OFF FROM WEST TO EAST SUNDAY NIGHT. PROBABLY COULD END THE ADVISORY EARLIER THAN 12Z MONDAY OVER MN/IA...BUT KEPT IT GOING FOR SIMPLICITY. ONE OTHER CONCERN IS THE WESTERLY WINDS THAT WILL KICK IN BEHIND THE SYSTEM. WITH THE LIGHT FLUFFY NATURE OF THE NEW SNOW...IT WILL PROBABLY BE MOVED AROUND WITH THE WIND. DO NOT FEEL IT WILL BE TRUE BLOWING SNOW HOWEVER... BUT RATHER JUST SOME DRIFTING IN OPEN AREAS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 206 PM CST SAT DEC 7 2013 HIGH PRESSURE BUILDS IN AGAIN ON MONDAY...BUT THE AREA WILL REMAIN UNDER NORTHWEST FLOW ALOFT. SEVERAL PASSING WEAK SHORT WAVE TROUGHS IN THE FLOW MAY RESULT IN SOME LIGHT SNOW OR FLURRIES FROM TIME TO TIME. ONE SUCH DISTURBANCE COMES THROUGH MONDAY NIGHT INTO TUESDAY ACROSS NORTHERN WI...AND ANOTHER COMES THROUGH TUESDAY NIGHT...AND YET ANOTHER THURSDAY AND FRIDAY. IT WILL REMAIN QUITE CHILLY THROUGH THE COMING WEEK AS WELL...WITH TEMPERATURES REMAINING WELL BELOW NORMAL ALL THROUGH THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 132 AM CST SUN DEC 8 2013 LIGHT SNOW IS RAPIDLY DEVELOPING AND/OR SPREADING INTO THE TAF SITES...LIKELY A CONSEQUENCE OF THE AIRMASS BEING SO COLD TO BEGIN WITH. VISIBILITIES HAVE ALREADY DROPPED TO MVFR AT RST WITH SNOW LIKELY TO BEGIN SOON AT LSE WITH FLURRIES BEING OBSERVED AT OUR OFFICE. VISIBILITIES AT BOTH TAF SITES SHOULD DROP TO IFR WITHIN A FEW HOURS AFTER THE SNOW STARTS...I.E. 09Z AT RST AND 12Z AT LSE. CEILINGS ARE ALSO LOWERING QUICKLY UPSTREAM TO THE WEST WITH MVFR CEILINGS LIKELY BY 12Z. FURTHER LOWERING IN CEILINGS AND VISIBILITIES ARE EXPECTED THIS AFTERNOON AS SNOW PICKS UP INTENSITY. THERE MAY EVEN BE A PERIOD OF LIFR VISIBILITIES DURING THE AFTERNOON/EARLY EVENING HOURS. SNOW SHOULD THEN BEGIN TAPERING OFF TOWARDS 06Z...HELPING VISIBILITIES IMPROVE. FLUFFY SNOW ACCUMULATIONS OF NEAR 3 INCHES ARE EXPECTED TODAY WITH ANOTHER INCH OR SO DURING THE EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM CST MONDAY FOR WIZ017-029-032>034-041. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST MONDAY FOR WIZ042>044-053>055-061. MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ079-086-087- 094-095. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM CST MONDAY FOR MNZ088-096. IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR IAZ008-009-018- 019. WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 AM CST MONDAY FOR IAZ010-011-029-030. && $$ UPDATE...AJ SHORT TERM...MW LONG TERM....MW AVIATION...AJ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
913 PM MST MON DEC 9 2013 .UPDATE... && .SHORT TERM...GUSTY WINDS CONTINUE IN/BASE OF THE FOOTHILLS THIS EVENING BUT THERE HAS BEEN A DECREASING TREND DURING THE PAST 2 HOURS. STRONGEST SUBSIDENCE HAS MOVED AWAY WHICH HELPED TO ENHANCE THE STRONGER WINDS EARLIER THIS EVENING. CROSS SECTIONS SHOWING STRONGEST WINDS WILL RECEED INTO THE HIGHER FOOTHILLS OVERNIGHT. STILL COULD BE SOME GUSTY WINDS IN THE 40-60 MPH RANGE BUT STILL DON`T THINK IT WILL BE A WIDESPREAD HIGH WIND EVENT. WITH THESE UPDATES HAVE INCREASED WINDS AND TRENDS FOR THE REST OF TONIGHT AND FOR HIGHER WINDS IN THE MOUNTAINS ON TUESDAY. SURFACE GRADIENT WILL RELAX TUESDAY AFTERNOON AS WEAK FRONT WILL DIMINISH THE GRADIENT ACROSS THE STATE. .AVIATION...STILL QUITE WINDY AT BJC AND WILL EXTEND THE STRONG WEST WINDS THROUGH ABOUT 08Z AND THEN DECREASE A BIT. WINDS AT DEN WILL CONTINUE TO DECREAE AND SHIFT MORE SOUTHWEST OVERNIGHT THOUGH THERE COULD BE AN OCCASIONAL PUFF OF WEST WINDS DURING THE NIGHT. WEAK SURFACE FRONT WILLL MOVE ACROSS TERMINALS LATE TUE AFTERNOON AS WINDS SHIFT NORTH AND NORTHEAST. && .PREV DISCUSSION... /ISSUED 625 PM MST MON DEC 9 2013/ UPDATE... SHORT TERM...STRONG AND GUSTY WINDS HAVE DEVELOPED IN THE LOWER AND BASE OF FOOTHILLS WITH A FEW LOCALIZED HIGH WIND GUSTS BETWEEN GOLDEN AND BOULDER. MOST OTHER AREAS ARE MUCH LOWER...GENERALLY IN THE 30-50 MPH RANGE. BEING SO LOCALIZED WILL NOT ISSUE A HIGH WIND WARNING FOR NOW. GOOD MOUNTAIN WAVE SET UP AS 00Z DENVER SOUNDING SHOWED STRONG INVERSION AT 700MB WHILE SURFACE GRADIENT AROUND 12MB ACROSS THE STATE. QG FIELDS ALSO SHOWING VERY STRONG SUBSIDENCE AS RAP SHOWED +50 ON THE QG VERTICAL VELOCITY FIELDS AT 500MB. WILL WATCH THIS CLOSELY THIS EVENING IN CASE OBSERVATIONS SHOW THE STRONGER WINDS BECOME MORE WIDESPREAD. AVIATION...GUSTY WEST WINDS HAVE NOW SURFACED AT KDEN AND HAVE ADDED STRONGER WINDS AT THE TERMINAL UNTIL 03Z. EXPECT GUSTY WINDS TO CONTINUE AT BJC IN THE 25-40KT RANGE. WINDS WILL GRADUALLY DECREASE IN BOTH LOCATIONS LATER THIS EVENING. PREV DISCUSSION... /ISSUED 338 PM MST MON DEC 9 2013/ SHORT TERM...SUBSIDENCE BEHIND THIS MORNING`S WEAK TROUGH COMBINED WITH INCREASING PRESSURE GRADIENT FROM GJT TO DEN AND MIXING TO PRODUCE GUSTY WINDS ACROSS MOUNTAINS AS WELL AS IN AND NEAR FOOTHILLS. LATEST RAP ANALYSIS SHOWING THE MAIN BATCH OF SUBSIDENCE NOW MOVING OVERHEAD. MOST GUSTS WERE AROUND 40 MPH...THOUGH THERE WERE GUSTS AROUND 55 MPH IN WIND PRONE AREAS IN THE FOOTHILLS OF NORTHERN JEFFERSON COUNTY. WINDS WERE LESS FURTHER AWAY FROM THE FOOTHILLS. THE GUSTY WINDS WERE PRODUCING SOME BLOWING SNOW...CONFINED TO OPEN AREAS. THE GUSTY WINDS WILL PERSIST INTO THE EVENING THEN RETREAT INTO THE HIGHER FOOTHILLS BY MIDNIGHT AS MIXING AND SUBSIDENCE WEAKENS. BUT THESE WINDS SHOULD ALSO STRENGTHEN AS CROSS MOUNTAIN FLOW INCREASES TO AROUND 40 KTS. THIS COULD RESULT IN GUSTS AROUND 65 MPH IN WIND PRONE AREAS. NOT EXPECTING THE GUSTS REACHING HIGH WIND CRITERIA OF 75 MPH AT THIS TIME. SOME BLOWING SNOW WILL BE POSSIBLE...ESPECIALLY IN OPEN AREAS. A BIT OF MOISTURE STILL TRAPPED ACROSS THE MOUNTAIN AND THERE MAY BE A FEW LIGHT SNOW SHOWERS OR FLURRIES. OVERNIGHT TEMPERATURES EXPECTED TO FALL INTO THE SINGLE DIGITS ACROSS THE PLAINS WITH BELOW ZERO READINGS IN THE HIGH COUNTRY AND LOW LYING AREAS NEAR LIMON AND GREELEY. TEMPERATURES TO BE WARMER IN AND NEAR FOOTHILLS DUE TO THE DOWNSLOPE WINDS. ON TUESDAY...NORTHWEST FLOW ALOFT TO PREVAIL. THERE WILL BE SOME WARMING DUE TO UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT BASIN AND DOWNSLOPE WINDS ALONG FOOTHILLS. TEMPERATURES ACROSS THE PLAINS TO WARM INTO THE LOWER 30S...WITH UPPER 20S IN THE LOW LYING AREAS. MOUNTAIN AREAS SHOULD WARM INTO THE TEENS BUT GUSTY WINDS WILL KEEP WIND CHILL READINGS BELOW ZERO. GUIDANCE VALUES STILL A BIT OPTIMISTIC WITH THE WARMUP. SOME MOISTURE AND WEAK LIFT MOVES INTO THE NORTHERN MOUNTAINS...ENOUGH FOR A SLIGHT CHANCE OF LIGHT SNOW. ANY ACCUMULATIONS TO BE MINIMAL. LONG TERM...WEATHER THE NEXT WEEK WILL BE DOMINATED BY A RIDGE OVER COLORADO. WEAK RIPPLES COMING NORTH OF US IN WESTERLY FLOW AND A WEAK LOW PASSING WELL SOUTH OF US. ALL OF THESE THINGS CONTINUE TO GET WEAKER WITH SUBSEQUENT MODEL RUNS AND SHOULD NOT HAVE MUCH EFFECT ON OUR WEATHER. THERE WILL BE A CHANCE OF LIGHT SNOW IN THE MOUNTAINS WITH THE TAIL END OF THE NORTHERN SHORT WAVES...AND WEAK SURGES OF COOL AIR FROM THE NORTH AS WELL. THESE WILL COME ABOUT FRIDAY AND AGAIN ON SUNDAY OR MONDAY...BRINGING A LITTLE COOLING...OR DELAYING THE WARMING...EACH DAY. BY THE END OF THE WEEK THE AIR ALOFT WILL BE QUITE WARM...BUT THE LOW LEVELS WILL LAG BEHIND. ALL OF THIS IS WELL COVERED IN THE CURRENT FORECAST AND THE MODEL CONSENSUS LOOKS GOOD. AVIATION...WESTERLY WINDS HAVE PUSHED ACROSS THE AREA AIRPORTS WITH GUSTS AROUND 35 KTS AT KBJC. WINDS MUCH LESS AT KDEN AND KAPA...AROUND 12 KTS. WINDS AT KDEN AND KAPA WILL TRANSITION TO DRAINAGE BY 02Z...REMAINING WESTERLY AT KBJC. SOME GUSTS COULD AGAIN REACH 35 KTS AT KBJC OVERNIGHT. ON TUESDAY...WINDS WILL WEAKEN AND BECOME NORTHWEST BY 17Z...SPEEDS AROUND 8 KTS. VFR TO CONTINUE WITH UNLIMITED CEILINGS. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN LONG TERM....GIMMESTAD AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
1231 AM EST TUE DEC 10 2013 .AVIATION... VFR CONDITIONS WILL BE PREVALENT INTO WEDNESDAY. A FEW MAINLY AFTERNOON AND OVERNIGHT SHOWERS ARE POSSIBLE...BUT PROBS ARE LOW AND VCSH LEFT OUT OF 6Z TAFS. WINDS WILL BE LIGHT AND SE TONIGHT...INCREASING TO 10 KTS TUESDAY. GULF BREEZE SHOULD TRANSITION WINDS TUESDAY AFTERNOON AT NAPLES TO WSW. && .PREV DISCUSSION... /ISSUED 817 PM EST MON DEC 9 2013/ UPDATE... HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC WATERS EXTENDING BACK WEST INTO SOUTH FLORIDA...AS A COLD FRONT SLOWLY DRIFTS SOUTH THROUGH NORTH FLORIDA. THIS WILL KEEP THE WEATHER DRY OVER SOUTH FLORIDA TONIGHT ALONG WITH LIGHT WINDS AND MOSTLY CLEAR SKIES OVER THE MAINLAND AREAS. SO FOG FORMATION IS EXPECTED OVERNIGHT TONIGHT OVER THE INTERIOR AND WEST COAST METRO AREAS...WITH EVEN AREAS OF FOG OVER THE INTERIOR SECTION TOWARDS SUNRISE. FOR THE MARINE SECTION OF SOUTH FLORIDA...THE WINDS WILL REMAIN FROM THE EASTERLY DIRECTION AT 10 TO 15 KNOTS TONIGHT. THIS WILL KEEP THE SEAS IN THE ATLANTIC WATERS AT 2 TO 4 FEET AND IN THE GULF WATERS AT 1 TO 3 FEET. SO ON CHANGES ARE EXPECTED IN THE MARINE PACKAGE FOR TONIGHT. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. UPDATE...54/BNB PREV DISCUSSION... /ISSUED 152 PM EST MON DEC 9 2013/ DISCUSSION... QUIET WEATHER WILL CONTINUE THROUGH TONIGHT, WITH WINDS BECOMING LIGHT AND VARIABLE TO CALM OVER THE INTERIOR AREAS. THERE COULD BE A ROUND OF FOG DEVELOPMENT. THE HRRR DOES KEEP IT OUT OF ITS FORECAST THROUGH 04Z, WHICH IS THE EXTENT OF THE RUN AT THIS TIME. HOWEVER, BUFKIT IS SHOWING THAT IT DOES FAVOR FOG. SO, HAVE KEPT PATCHY FOG IN THE FORECAST FROM 06Z THROUGH 12Z. PATTERN WISE, HIGH PRESSURE WILL WEAKEN THROUGH THE NIGHT. THIS IS AHEAD OF A COLD FRONT THAT IS CURRENTLY WELL TO THE WEST, OVER NEW ORLEANS. THIS FRONT WILL APPROACH THE FLORIDA PENINSULA AND WILL BE ENHANCED BY A 500 MB SHORT WAVE. HOWEVER, AS IT APPROACHES FLORIDA, THE ASSOCIATED LOW WILL BE QUICKLY MOVING OFF TO THE NORTHEAST, TAKING MOST OF THE ENERGY AND MOISTURE WITH IT. THIS WILL CAUSE THE FRONT TO STALL SOMEWHERE OVER NORTH CENTRAL FLORIDA WEDNESDAY NIGHT. AHEAD OF THIS FRONT, THERE WILL BE AN AREA OF CLOUDS AND SHOWERS THAT WILL BEGIN TO AFFECT THE SOUTHERN TIP OF FLORIDA TOMORROW MORNING. MODELS ARE IN DISAGREEMENT WITH THE EXTENT OF THE COVERAGE OF THE SHOWERS. THE GFS KEEPS MOST OF THE ACTIVITY TO THE SOUTH OF I75, BUT IT DOES HAVE SHOWERS OVER THE PENINSULA. THE ECMWF KEEPS ALL ACTIVITY OFFSHORE, EXCEPT PERHAPS A LIGHT COASTAL SHOWER. HAVE KEPT A CHANCE OF SHOWERS FOR MOST AREAS SOUTH OF I75 AND A SLIGHT CHANCE NORTH OF THAT FOR THE AFTERNOON HOURS. AFTER THAT, MOST OF THE ACTIVITY IS EITHER OVER THE COASTAL WATERS, OR JUST ALONG THE COAST, WITH INLAND AREAS FAIRLY DRY. BY WEDNESDAY AFTERNOON, THE FRONT LOOKS TO DRIFT FAR ENOUGH SOUTH TO BRING A CHANCE OF SHOWERS TO AREAS NORTH OF I75. AFTER THAT, A SECONDARY HIGH BUILDS OVER THE MISSISSIPPI VALLEY, WHICH WILL PUSH THE FRONT FURTHER SOUTH AND OVER THE FLORIDA STRAIGHTS. AS IT DOES, IT MAY ENHANCE SHOWER ACTIVITY THURSDAY AFTERNOON AND EVENING. THEN, EASTERLY FLOW RETURNS AS THE SURFACE HIGH SLIDES EASTWARD. ALSO, AN UPPER LEVEL RIDGE WILL BE BUILDING OVER THE AREA FOR THE WEEKEND. THIS WILL PROBABLY BRING MOSTLY DRY CONDITIONS FOR THE WEEKEND, WITH THE EXCEPTION OF A SLIGHT CHANCE OF SHOWERS BY SUNDAY. MARINE... HIGH PRESSURE WILL BEGIN TO WEAKEN TONIGHT. THIS WILL BRING WINDS AROUND TO THE SOUTH TOMORROW AS WELL AS SOME SHOWERS TO THE SOUTH FLORIDA COASTAL WATERS. A COLD FRONT WILL APPROACH THE AREA WEDNESDAY NIGHT AND STALL OVER CENTRAL FLORIDA AND ALL BUT DISSIPATE. HIGH PRESSURE WILL QUICKLY TO THE NORTH, BEHIND THE FRONT. THIS WILL BRING AN EASTERLY FLOW BACK TO THE SOUTH FLORIDA WATERS WEDNESDAY. WITH THE WEAK FRONTAL BOUNDARY IN THE AREA, IT WILL BRING A CHANCE OF SHOWERS FOR THE COASTAL WATERS THROUGH THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 70 82 68 80 / 20 30 20 30 FORT LAUDERDALE 71 82 70 82 / 30 30 20 30 MIAMI 72 83 70 83 / 30 30 20 30 NAPLES 67 82 66 83 / 20 30 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...84/AK AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
358 AM EST TUE DEC 10 2013 .SHORT TERM /TODAY THROUGH WEDNESDAY/... SHORT TERM MODELS ARE IN GOOD AGREEMENT FOR THE MOST PART ALTHOUGH SOME DISCREPANCIES NOTED...NAM/SREF FASTER AND GFS/ECMWF SLOWER TO PUSH FRONT THROUGH FORECAST AREA TODAY. RAP HAS INITIALIZED WELL AND IS HANDLING THE RAIN BAND OVER NORTHWEST GEORGIA FAIRLY WELL AND IS IN LINE WITH FASTER SOLUTIONS. TEMPERATURES REMAIN IN THE LOWER 40S ACROSS NORTHWEST GEORGIA AND WITH SLOW PROGRESS OF COLDER AIR TO THE NORTH DO NOT EXPECT WINTRY PRECIP IN THE FORECAST AREA. COLDER AIR WILL FILTER INTO PORTIONS OF NORTH GEORGIA BY MID-LATE MORNING...AND MODELS ARE TRYING TO SCATTER/CLEAR SKIES RAPIDLY BEHIND THE FRONT. THIS WILL RESULT IN MAXIMUM TEMPERATURES ACROSS NORTH GEORGIA...INCLUDING THE ATLANTA METRO AREA...THIS MORNING. COLD AIR ADVECTION BEHIND THE FRONT IS NOT IMPRESSIVE...BUT SHOULD BE ENOUGH TO OFFSET ANY HEATING BY THE SCATTERING CLOUDS WHICH WILL RESULT IN SEVERAL HOURS OF NEAR STEADY TEMPERATURES ACROSS NORTH GEORGIA. 1000-850 WINDS WILL INCREASE BEHIND THE FRONT WITH GUSTS OF 25-30MPH EXPECTED BY LATE MORNING IN NORTH GEORGIA...SPREADING SOUTHWARD INTO CENTRAL GEORGIA BY EARLY AFTERNOON AND CONTINUING THROUGH EARLY THIS EVENING. DRIER AIR FILTERING INTO THE FORECAST AREA BY TONIGHT...BUT WIND SPEEDS WILL REMAIN IN THE 5-10MPH RANGE OVERNIGHT WHICH WILL KEEP TEMPERATURES FROM RADIATING OUT AS MUCH AS THEY COULD...HOWEVER TEMPERATURES WILL DROP TO LOWER TO MID 20S NORTH GEORGIA AND IN THE MID 30S OVER CENTRAL GEORGIA BY MORNING. TEMPERATURES WILL MODERATE ON WEDNESDAY TO NEAR NORMAL AS DRY WEATHER AND MOSTLY CLEAR SKIES SET UP ACROSS THE AREA. ATWELL .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... EXTENDED BEGINS WITH LONGWAVE TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...WITH ANOTHER SHORTWAVE DIVING THROUGH THE CENTRAL PLAINS. THIS DRY WAVE WILL PUSH INTO THE SOUTHEAST THURSDAY MORNING BUT WILL BRING A REINFORCING SHOT OF COOL AIR TO THE REGION. WEAK RIDGING BUILDS IN ALOFT FRIDAY AHEAD OF A STRONG SYSTEM OVER THE DESERT SOUTHWEST. SURFACE LOW WILL PUSH INTO THE SOUTHERN PLAINS FRIDAY NIGHT...WITH STRONG SOUTHERLIES PUMPING GULF MOISTURE BACK INTO THE SOUTHEAST. PRECIP OVERSPREADS THE AREA FRIDAY NIGHT AND ESPECIALLY SATURDAY...AND GIVEN AGREEMENT BETWEEN GFS AND ECMWF AS WELL AS RUN-TO-RUN CONSISTENCY...HAVE INCREASED POPS TO CATEGORICAL ON SATURDAY. LOOKS LIKE EASILY ANOTHER INCH OF RAIN ACROSS THE AREA. THERE MAY BE ENOUGH INSTABILITY CREEPING INTO SOUTHERN ZONES SATURDAY AFTERNOON TO WARRANT ADDING THUNDER TO THE FORECAST...BUT HAVE LEFT IT OUT FOR NOW. COMPLICATING FACTOR IS DIABATICALLY ENHANCED CLASSICAL CAD DEVELOPING FRIDAY NIGHT AND EARLY SATURDAY...THOUGH RIGHT NOW THICKNESSES ACROSS GEORGIA FOR THE MOST PART LOOK TOO WARM FOR ANY WINTRY PRECIP...BUT LATER FORECASTS WILL HAVE TO BE REEVALUATED. DID ADD A BRIEF RAIN/SNOW MIX EXTREME NORTH SUNDAY MORNING AS THE COLD FRONT PUSHES THROUGH. GFS IS JUST A TAD FASTER THAN THE ECMWF BY THIS POINT SO UNCERTAINTY IS INCREASING. COOL AND WINDY BEHIND THE FRONT BUT CLEARING INTO EARLY NEXT WEEK. TDP && .AVIATION... 06Z UPDATE... IFR TO MVFR CONDITIONS WILL DETERIORATE TO IFR...SOME LIFR AT TAF SITES. LIGHT RAIN MOVING ACROSS TAF SITES MAINLY THIS MORNING WILL AID IN IMPROVING CIGS TO MVFR. COLDER AIR FILTERING IN MAY STALL CLEARING SKIES BUT WILL GO VFR AFTER 18-20Z. WINDS WILL INCREASE OUT OF NW 10-15KTS WITH GUSTS TO 27KTS EXPECTED. //ATL CONFIDENCE...06Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. ATWELL && .PRELIMINARY POINT TEMPS/POPS... ATHENS 53 28 55 29 / 80 0 5 5 ATLANTA 50 30 55 31 / 80 0 5 5 BLAIRSVILLE 47 22 52 23 / 60 0 5 5 CARTERSVILLE 48 24 53 26 / 70 0 5 5 COLUMBUS 59 32 59 36 / 50 0 5 5 GAINESVILLE 50 29 53 31 / 80 0 5 5 MACON 61 28 58 30 / 80 0 5 5 ROME 47 22 52 25 / 50 0 5 5 PEACHTREE CITY 49 25 55 28 / 80 0 5 5 VIDALIA 69 39 59 40 / 70 5 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ATWELL LONG TERM....TDP AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
326 AM CST TUE DEC 10 2013 .DISCUSSION... 718 PM CST ONLY ISSUES THUS FAR HAVE BEEN TEMPERATURES TAKING A NOSE DIVE. RFD DROPPED TO 3 DEGREES ALREADY WITH OTHER STATIONS UNDER CLEAR SKIES TANKING AS WELL. AS LOWERED LOW TEMPS FOR TONIGHT WITH OUTLYING AREAS DIPPING JUST BELOW ZERO. BASED ON TRENDS...TEMPS MAY FALL A BIT LOWER THAN CURRENTLY FORECAST FOR AREAS NORTH OF A LASALLE TO OHARE AIRPORT LINE. BASICALLY WHERE THE SKY IS CLEAR. USED HRRR TRENDS WITH A FEW HAND EDITS TO GET TEMP TREND TONIGHT SINCE AREAS UNDER THE CLOUD COVER WILL COOL VERY SLOWLY. ISSUED A SPS TO HIGHLIGHT THE COLD TEMPS AND WIND CHILLS SINCE THIS IS THE COLDEST WE HAVE BEEN THIS SEASON. MIN WIND CHILLS OF -10 TO -15 ARE EXPECTED FOR AREAS IN AND NORTH OF A LASALLE COUNTY TO WILL COUNTY LINE. ISOLATED AREAS NORTH OF I-90 MAY EVEN SEEN MIN WIND CHILLS APPROACHING -20. HOWEVER THE AREA OF -20 WILL NOT BE WIDESPREAD ENOUGH TO WARRANT A WIND CHILL ADVISORY. OTHERWISE MADE MINOR ADJUSTMENTS TO SKY COVER AS THE REST OF THE FORECAST IS ON TRACK. STILL EXPECTING TEMPS TO RISE A BIT AROUND SUNRISE AS CLOUD COVER ASSOCIATED WITH THE NEXT CLIPPER MOVE IN. JEE //PREV DISCUSSION... 253 PM CST IT APPEARS WE ARE STUCK IN MOTHER NATURES WINTER PATTERN...AND FOR THE NEXT SEVERAL DAYS IT DOES NOT APPEAR WE ARE LOOKING AT A BREAK FROM THIS SETUP. LONG-TERM PATTERN IS BEGINNING TO SHOW JUST A BRIEF RESPITE...THEN A RETURN TO UNSEASONABLY COLD SETUP. IT`S THE GIFT THAT KEEPS ON GIVING CLARK. THIS AFTERNOON/EVENING...WILL REMAIN RELATIVELY QUIET FOR THE FORECAST AREA...HOWEVER THAT WILL CHANGE TOWARDS DAYBREAK TUESDAY. SFC RIDGE HAS BECOME CENTERED ACROSS THE MID-MISSOURI VALLEY...BEGINNING TO STRETCH EAST THROUGH THE OHIO VALLEY. THE DEPARTING SFC LOW THAT BROUGHT THE FRESH BLANKET OF SNOW HAS LIFTED NORTHEAST OF LAKE HURON...MEANWHILE A CLIPPER IS BEGINNING TO DIP INTO THE NORTHERN PLAINS LATE THIS AFTERNOON. IR IMAGERY SHOWS A CHANNEL OF CLOUDS OVER SAINT LOUIS STRETCHING NORTHEAST THROUGH SOUTHERN LAKE MICHIGAN...ASSOCIATED WITH A FRONTAL BOUNDARY THAT CONTINUES TO SLOWLY SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA. TEMPS AHEAD OF THIS BOUNDARY HAVE HELD STEADY IN THE LOW 20S...WHILE BEHIND THIS BOUNDARY TEMPS HAVE ALREADY FALLEN INTO THE MID/UPR TEENS. ACROSS THE STATELINE INTO IOWA...TEMPS HAVE HELD IN THE SINGLE DIGITS ABOVE ZERO. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH WITH THE FIRST CLIPPER TONIGHT...AND AS A RESULT HAVE INCREASED POPS ACROSS THE NORTHERN CWFA. THE PRESSURE GRADIENT DOES INCREASE THIS EVENING...AND WILL PERSIST THRU DAYBREAK TUE. THIS WILL LIKELY RESULT IN SOME BLOWING SNOW. AS NOTED ABOUT INCREASED POPS...THIS HAS RESULTED IN LIGHT SNOW EXPECTED JUST BEFORE DAYBREAK TUE FOR THE NORTHERN HALF OF THE CWFA. USING THE COBB TECHNIQUE WOULD SUGGEST A FEW POINTS BETWEEN 09-12Z COULD PICK-UP A COUPLE TENTHS OF AN INCH OF SNOWFALL. WITH THE BREEZY CONDS EXPECTED...AND COLD AIR IN PLACE...TEMPS WILL LIKELY TUMBLE TO THE SINGLE DIGITS ABOVE ZERO AND WIND CHILL VALUES WELL BELOW ZERO AND NEARING -15 IN A FEW LOCATIONS WEST OF THE FOX VALLEY. CONFIDENCE...HIGH. TUESDAY THROUGH WEDNESDAY... 500MB TROUGH AXIS HAS TRENDED STRONGER...WHICH HAS ALSO DISPLACED THE CLIPPER POISED TO ARRIVE ACROSS THE REGION FURTHER SOUTH TUE MORNING. AS A RESULT HAVE INTRODUCED POPS TO ACCOMMODATE THIS THRU 18Z TUE. BUT IN TRADITIONAL FASHION...THIS CLIPPER SHUD QUICKLY PUSH EAST BY EARLY AFTN WITH WEAK SFC RIDGING PUSHING BACK INTO THE FORECAST AREA. SOME WEAK WARMING MAY OCCUR WITH THIS SYSTEM EARLY...ALLOWING TEMPS TO WARM INTO THE TEENS TO PSBLY LOW 20S ALONG THE SOUTHERN CWFA TUE AFTN. THEN YET ANOTHER CLIPPER IS PROGGED TO TRAVERSE THE REGION LATE TUE NGT/WED...WHICH HAS CONTINUED TO TREND FURTHER SOUTH AND STRONGER. WITH THE SFC RIDGE DRIFTING SOUTH INTO THE TENN VALLEY...THIS WILL LIKELY ALLOW THE WAVE TO PUSH ACROSS THE HEART OF THE CWFA. QPF OF ARND 0.10" FOR THIS SECOND CLIPPER SNOW RATIOS WILL HOVER ARND 15:1 TO 20:1. THE BEST OMEGA/LIFT IS PUSHING INTO THE FAVORED DGZ WED MORNING...WHICH COULD HELP PRODUCE LARGER DENDRITES AND INCREASE SNOWFALL ACCUM RATES. AT THIS POINT HAVE ACCUMS GENERALLY BETWEEN 1-3"...AND COULD SEE A FEW LOCATIONS BETWEEN THE I-80 AND I-88 CORRIDOR COULD PICK UP CLOSE TO 4" BY LATE WED MORNING. THEN HIGH PRESSURE BUILDS BACK INTO THE REGION WED NGT...SETTING THE STAGE FOR A VERY COLD NIGHT INTO THUR MORNING. THE RIDGE CENTER HAS ALSO TRENDED SLIGHTLY FURTHER SOUTH...WHICH WILL LIKELY KEEP SOME WEST/NORTHWEST WIND COMPONENT. DESPITE THIS TEMPS SHUD STILL RADIATE INTO THE SINGLE DIGITS BELOW ZERO. CONFIDENCE...HIGH. CONFIDENCE IN ACCUMULATING SNOWFALL WED...HIGH. THURSDAY THROUGH SUNDAY... PREVIOUS GUIDANCE HAD HELD THE SFC RIDGE OVER THE FORECAST AREA THUR MORNING...WITH DRY WEATHER. HOWEVER AS HAS BEEN THE CASE WITH THE PRIOR COUPLE OF CLIPPERS...AND PLACEMENT OF THE 500MB TROUGH AXIS...GUIDANCE HAS NOW INTRODUCED YET ANOTHER CLIPPER SLICING SOUTHEAST ACROSS THE NORTHERN PLAINS EARLY THUR...AND COULD BRING A PERIOD OF LIGHT SNOW/FLURRIES INTO NORTHERN IL THUR MORNING. THIS MAY RESULT IN TEMPS THUR MORNING NOT GETTING AS COLD...BUT THAT WILL HINGE UPON TIMING AND CLOUD COVER FROM THE AFOREMENTIONED CLIPPER. THEN A RELATIVELY QUIET PERIOD FOR FRI WITH THE 500MB FLOW TRYING TO FLATTEN...BUT THIS WILL ONLY BE BRIEF. GUIDANCE IS NOW BEGINNING TO TREND TOWARDS AN INVERTED TROUGH DEVELOPING IN THE WAKE OF THE SFC RIDGE FRI...WITH A STRONG SHORTWAVE TAKING SHAPE ACROSS THE SOUTHERN PLAINS FRIDAY EVENING. THIS SYSTEM WILL NEED TO BE CLOSELY MONITORED FOR THE UPCOMING WEEKEND...AS THIS COULD SPREAD ACCUMULATING SNOWFALL THROUGH THE OHIO VALLEY INTO NORTHERN IL/NORTHWEST IN. THE LATEST GFS INDICATES AN 850MB LOW ASSOCIATED WITH THIS INVERTED TROUGH...LIFTING NORTHEAST ACROSS CENTRAL IL THEN NORTHEAST INTO NORTHCENTRAL IN MIDDAY SAT. LLVL FLOW AHEAD OF THIS FEATURE WILL BE TURNING NORTHEAST SAT...SETTING UP THE POTENTIAL FOR A HYBRID SYSTEM OF LAKE EFFECT SNOW AND POTENTIALLY SYNOPTIC SNOW SAT. TEMPS SHUD BEGIN TO WARM TO NEAR 30 DEG...OR POSSIBLY THE FREEZING POINT FRI THRU SAT. THEN WITH YET ANOTHER ARCTIC AIRMASS POISED TO PUSH BEHIND THIS SYSTEM SUN. CONFIDENCE...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * STRONG WESTERLY WINDS DURING THE DAY TUESDAY...WITH GUSTS IN EXCESS OF 30 KT. * POTENTIAL FOR LIGHT FLURRIES OR A FEW SNOW SHOWERS LATE MORNING/EARLY AFTERNOON. * MORE SIGNIFICANT SNOW POTENTIAL LATE TUESDAY NIGHT. BMD //DISCUSSION...UPDATED 06Z... TRANSIENT SURFACE RIDGE IS PUSHING ACROSS THE AREAS THIS EVENING ALLOWING WINDS TO BRIEFLY BACK TO THE SSW/SW AND WEAKEN. WINDS WILL VEER TO THE WSW AGAIN TOMORROW AFTER DAYBREAK AS A CLIPPER SYSTEM SKIRTS JUST NORTH OF THE AREA. A TIGHT GRADIENT AND STRONG CHANGES IN THE SURFACE PRESSURE WILL RESULT IN A SHARP INCREASE IN WINDS. WINDS AT THE TOP OF THE MIXED LAYER ARE AROUND 35 KTS AND WOULD EXPECT TO TAP INTO THESE STRONGER WINDS BY EARLY AFTERNOON. MAIN FORCING ASSOCIATED WITH THE UPPER WAVE WILL BE FOCUSED OVER WISCONSIN...THOUGH SOME LIFT IS NOTED SOUTH INTO NORTHERN ILLINOIS WHERE THE MOISTURE IS SHALLOW. DESPITE THE MEAGER MOISTURE...A FEW FLURRIES ARE POSSIBLE THOUGH WOULD NOT ANTICIPATE ANY IMPACTS TO VSBY NOR ANY ACCUMULATION. WINDS WILL SETTLE AROUND SUNSET AS ANOTHER RIDGE TRANSLATES EAST ACROSS THE AREA...BUT YET ANOTHER CLIPPER SYSTEM WILL BE RIGHT ON ITS HEELS. THIS NEXT SYSTEM LOOKS TO TRACK RIGHT OVER NORTHERN ILLINOIS LATE TUESDAY NIGHT INTO EARLY WEDNESDAY...PIVOTING ACROSS THE TERMINALS WHICH COULD RESULT IN A FEW INCHES OF SNOW ACCUMULATION AND LIKELY PERIODS OF IFR VSBY. BMD //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM-HIGH CONFIDENCE IN WIND SPEEDS/DIRECTION. * LOW CONFIDENCE IN SNOW IMPACTING TERMINALS MIDDAY TUESDAY...THOUGH THERE IS AN AREA OF -SN EXPANDING OVER CENTRAL IOWA THAT WILL HAVE TO MONITOR. * MEDIUM-HIGH CONFIDENCE IN ACCUMULATING SNOW LATE TUESDAY NIGHT INTO EARLY WEDNESDAY. BMD //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...SNOW ENDING TOWARD MIDDAY. BECOMING VFR. THURSDAY...VFR. FRIDAY...VFR WITH SNOW CHANCES INCREASING FRIDAY EVENING. IFR DEVELOPING FRIDAY EVENING. SATURDAY...CHANCE FOR SNOW. IFR/MVFR. SUNDAY...IMPROVING TO VFR. MDB && .MARINE... 324 AM CST TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013- ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 AM TUESDAY TO 9 PM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 8 AM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1150 PM CST MON DEC 9 2013 .DISCUSSION... 718 PM CST ONLY ISSUES THUS FAR HAVE BEEN TEMPERATURES TAKING A NOSE DIVE. RFD DROPPED TO 3 DEGREES ALREADY WITH OTHER STATIONS UNDER CLEAR SKIES TANKING AS WELL. AS LOWERED LOW TEMPS FOR TONIGHT WITH OUTLYING AREAS DIPPING JUST BELOW ZERO. BASED ON TRENDS...TEMPS MAY FALL A BIT LOWER THAN CURRENTLY FORECAST FOR AREAS NORTH OF A LASALLE TO OHARE AIRPORT LINE. BASICALLY WHERE THE SKY IS CLEAR. USED HRRR TRENDS WITH A FEW HAND EDITS TO GET TEMP TREND TONIGHT SINCE AREAS UNDER THE CLOUD COVER WILL COOL VERY SLOWLY. ISSUED A SPS TO HIGHLIGHT THE COLD TEMPS AND WIND CHILLS SINCE THIS IS THE COLDEST WE HAVE BEEN THIS SEASON. MIN WIND CHILLS OF -10 TO -15 ARE EXPECTED FOR AREAS IN AND NORTH OF A LASALLE COUNTY TO WILL COUNTY LINE. ISOLATED AREAS NORTH OF I-90 MAY EVEN SEEN MIN WIND CHILLS APPROACHING -20. HOWEVER THE AREA OF -20 WILL NOT BE WIDESPREAD ENOUGH TO WARRANT A WIND CHILL ADVISORY. OTHERWISE MADE MINOR ADJUSTMENTS TO SKY COVER AS THE REST OF THE FORECAST IS ON TRACK. STILL EXPECTING TEMPS TO RISE A BIT AROUND SUNRISE AS CLOUD COVER ASSOCIATED WITH THE NEXT CLIPPER MOVE IN. JEE //PREV DISCUSSION... 253 PM CST IT APPEARS WE ARE STUCK IN MOTHER NATURES WINTER PATTERN...AND FOR THE NEXT SEVERAL DAYS IT DOES NOT APPEAR WE ARE LOOKING AT A BREAK FROM THIS SETUP. LONG-TERM PATTERN IS BEGINNING TO SHOW JUST A BRIEF RESPITE...THEN A RETURN TO UNSEASONABLY COLD SETUP. IT`S THE GIFT THAT KEEPS ON GIVING CLARK. THIS AFTERNOON/EVENING...WILL REMAIN RELATIVELY QUIET FOR THE FORECAST AREA...HOWEVER THAT WILL CHANGE TOWARDS DAYBREAK TUESDAY. SFC RIDGE HAS BECOME CENTERED ACROSS THE MID-MISSOURI VALLEY...BEGINNING TO STRETCH EAST THROUGH THE OHIO VALLEY. THE DEPARTING SFC LOW THAT BROUGHT THE FRESH BLANKET OF SNOW HAS LIFTED NORTHEAST OF LAKE HURON...MEANWHILE A CLIPPER IS BEGINNING TO DIP INTO THE NORTHERN PLAINS LATE THIS AFTERNOON. IR IMAGERY SHOWS A CHANNEL OF CLOUDS OVER SAINT LOUIS STRETCHING NORTHEAST THROUGH SOUTHERN LAKE MICHIGAN...ASSOCIATED WITH A FRONTAL BOUNDARY THAT CONTINUES TO SLOWLY SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA. TEMPS AHEAD OF THIS BOUNDARY HAVE HELD STEADY IN THE LOW 20S...WHILE BEHIND THIS BOUNDARY TEMPS HAVE ALREADY FALLEN INTO THE MID/UPR TEENS. ACROSS THE STATELINE INTO IOWA...TEMPS HAVE HELD IN THE SINGLE DIGITS ABOVE ZERO. GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH WITH THE FIRST CLIPPER TONIGHT...AND AS A RESULT HAVE INCREASED POPS ACROSS THE NORTHERN CWFA. THE PRESSURE GRADIENT DOES INCREASE THIS EVENING...AND WILL PERSIST THRU DAYBREAK TUE. THIS WILL LIKELY RESULT IN SOME BLOWING SNOW. AS NOTED ABOUT INCREASED POPS...THIS HAS RESULTED IN LIGHT SNOW EXPECTED JUST BEFORE DAYBREAK TUE FOR THE NORTHERN HALF OF THE CWFA. USING THE COBB TECHNIQUE WOULD SUGGEST A FEW POINTS BETWEEN 09-12Z COULD PICK-UP A COUPLE TENTHS OF AN INCH OF SNOWFALL. WITH THE BREEZY CONDS EXPECTED...AND COLD AIR IN PLACE...TEMPS WILL LIKELY TUMBLE TO THE SINGLE DIGITS ABOVE ZERO AND WIND CHILL VALUES WELL BELOW ZERO AND NEARING -15 IN A FEW LOCATIONS WEST OF THE FOX VALLEY. CONFIDENCE...HIGH. TUESDAY THROUGH WEDNESDAY... 500MB TROUGH AXIS HAS TRENDED STRONGER...WHICH HAS ALSO DISPLACED THE CLIPPER POISED TO ARRIVE ACROSS THE REGION FURTHER SOUTH TUE MORNING. AS A RESULT HAVE INTRODUCED POPS TO ACCOMMODATE THIS THRU 18Z TUE. BUT IN TRADITIONAL FASHION...THIS CLIPPER SHUD QUICKLY PUSH EAST BY EARLY AFTN WITH WEAK SFC RIDGING PUSHING BACK INTO THE FORECAST AREA. SOME WEAK WARMING MAY OCCUR WITH THIS SYSTEM EARLY...ALLOWING TEMPS TO WARM INTO THE TEENS TO PSBLY LOW 20S ALONG THE SOUTHERN CWFA TUE AFTN. THEN YET ANOTHER CLIPPER IS PROGGED TO TRAVERSE THE REGION LATE TUE NGT/WED...WHICH HAS CONTINUED TO TREND FURTHER SOUTH AND STRONGER. WITH THE SFC RIDGE DRIFTING SOUTH INTO THE TENN VALLEY...THIS WILL LIKELY ALLOW THE WAVE TO PUSH ACROSS THE HEART OF THE CWFA. QPF OF ARND 0.10" FOR THIS SECOND CLIPPER SNOW RATIOS WILL HOVER ARND 15:1 TO 20:1. THE BEST OMEGA/LIFT IS PUSHING INTO THE FAVORED DGZ WED MORNING...WHICH COULD HELP PRODUCE LARGER DENDRITES AND INCREASE SNOWFALL ACCUM RATES. AT THIS POINT HAVE ACCUMS GENERALLY BETWEEN 1-3"...AND COULD SEE A FEW LOCATIONS BETWEEN THE I-80 AND I-88 CORRIDOR COULD PICK UP CLOSE TO 4" BY LATE WED MORNING. THEN HIGH PRESSURE BUILDS BACK INTO THE REGION WED NGT...SETTING THE STAGE FOR A VERY COLD NIGHT INTO THUR MORNING. THE RIDGE CENTER HAS ALSO TRENDED SLIGHTLY FURTHER SOUTH...WHICH WILL LIKELY KEEP SOME WEST/NORTHWEST WIND COMPONENT. DESPITE THIS TEMPS SHUD STILL RADIATE INTO THE SINGLE DIGITS BELOW ZERO. CONFIDENCE...HIGH. CONFIDENCE IN ACCUMULATING SNOWFALL WED...HIGH. THURSDAY THROUGH SUNDAY... PREVIOUS GUIDANCE HAD HELD THE SFC RIDGE OVER THE FORECAST AREA THUR MORNING...WITH DRY WEATHER. HOWEVER AS HAS BEEN THE CASE WITH THE PRIOR COUPLE OF CLIPPERS...AND PLACEMENT OF THE 500MB TROUGH AXIS...GUIDANCE HAS NOW INTRODUCED YET ANOTHER CLIPPER SLICING SOUTHEAST ACROSS THE NORTHERN PLAINS EARLY THUR...AND COULD BRING A PERIOD OF LIGHT SNOW/FLURRIES INTO NORTHERN IL THUR MORNING. THIS MAY RESULT IN TEMPS THUR MORNING NOT GETTING AS COLD...BUT THAT WILL HINGE UPON TIMING AND CLOUD COVER FROM THE AFOREMENTIONED CLIPPER. THEN A RELATIVELY QUIET PERIOD FOR FRI WITH THE 500MB FLOW TRYING TO FLATTEN...BUT THIS WILL ONLY BE BRIEF. GUIDANCE IS NOW BEGINNING TO TREND TOWARDS AN INVERTED TROUGH DEVELOPING IN THE WAKE OF THE SFC RIDGE FRI...WITH A STRONG SHORTWAVE TAKING SHAPE ACROSS THE SOUTHERN PLAINS FRIDAY EVENING. THIS SYSTEM WILL NEED TO BE CLOSELY MONITORED FOR THE UPCOMING WEEKEND...AS THIS COULD SPREAD ACCUMULATING SNOWFALL THROUGH THE OHIO VALLEY INTO NORTHERN IL/NORTHWEST IN. THE LATEST GFS INDICATES AN 850MB LOW ASSOCIATED WITH THIS INVERTED TROUGH...LIFTING NORTHEAST ACROSS CENTRAL IL THEN NORTHEAST INTO NORTHCENTRAL IN MIDDAY SAT. LLVL FLOW AHEAD OF THIS FEATURE WILL BE TURNING NORTHEAST SAT...SETTING UP THE POTENTIAL FOR A HYBRID SYSTEM OF LAKE EFFECT SNOW AND POTENTIALLY SYNOPTIC SNOW SAT. TEMPS SHUD BEGIN TO WARM TO NEAR 30 DEG...OR POSSIBLY THE FREEZING POINT FRI THRU SAT. THEN WITH YET ANOTHER ARCTIC AIRMASS POISED TO PUSH BEHIND THIS SYSTEM SUN. CONFIDENCE...HIGH. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * STRONG WESTERLY WINDS DURING THE DAY TUESDAY...WITH GUSTS IN EXCESS OF 30 KT. * LOW POTENTIAL FOR LIGHT FLURRIES OR A FEW SNOW SHOWERS. * MORE SIGNIFICANT SNOW POTENTIAL LATE TUESDAY NIGHT. BMD //DISCUSSION...UPDATED 06Z... TRANSIENT SURFACE RIDGE IS PUSHING ACROSS THE AREAS THIS EVENING ALLOWING WINDS TO BRIEFLY BACK TO THE SSW/SW AND WEAKEN. WINDS WILL VEER TO THE WSW AGAIN TOMORROW AFTER DAYBREAK AS A CLIPPER SYSTEM SKIRTS JUST NORTH OF THE AREA. A TIGHT GRADIENT AND STRONG CHANGES IN THE SURFACE PRESSURE WILL RESULT IN A SHARP INCREASE IN WINDS. WINDS AT THE TOP OF THE MIXED LAYER ARE AROUND 35 KTS AND WOULD EXPECT TO TAP INTO THESE STRONGER WINDS BY EARLY AFTERNOON. MAIN FORCING ASSOCIATED WITH THE UPPER WAVE WILL BE FOCUSED OVER WISCONSIN...THOUGH SOME LIFT IS NOTED SOUTH INTO NORTHERN ILLINOIS WHERE THE MOISTURE IS SHALLOW. DESPITE THE MEAGER MOISTURE...A FEW FLURRIES ARE POSSIBLE THOUGH WOULD NOT ANTICIPATE ANY IMPACTS TO VSBY NOR ANY ACCUMULATION. WINDS WILL SETTLE AROUND SUNSET AS ANOTHER RIDGE TRANSLATES EAST ACROSS THE AREA...BUT YET ANOTHER CLIPPER SYSTEM WILL BE RIGHT ON ITS HEELS. THIS NEXT SYSTEM LOOKS TO TRACK RIGHT OVER NORTHERN ILLINOIS LATE TUESDAY NIGHT INTO EARLY WEDNESDAY...PIVOTING ACROSS THE TERMINALS WHICH COULD RESULT IN A FEW INCHES OF SNOW ACCUMULATION AND LIKELY PERIODS OF IFR VSBY. BMD //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH CONFIDENCE IN WIND SPEEDS/DIRECTION. * LOW CONFIDENCE IN SNOW IMPACTING TERMINALS MIDDAY TUESDAY...BUT MEDIUM-HIGH CONFIDENCE IF THERE IS ANY IT WOULD ONLY BE LIGHT FLURRIES WITH NO SIG IMPACTS TO VSBY. * MEDIUM-HIGH CONFIDENCE IN ACCUMULATING SNOW LATE TUESDAY NIGHT INTO EARLY WEDNESDAY. BMD //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...SNOW ENDING TOWARD MIDDAY. BECOMING VFR. THURSDAY...VFR. FRIDAY...VFR WITH SNOW CHANCES INCREASING FRIDAY EVENING. IFR DEVELOPING FRIDAY EVENING. SATURDAY...CHANCE FOR SNOW. IFR/MVFR. SUNDAY...IMPROVING TO VFR. MDB && .MARINE... 145 PM CST MAIN MARINE FORECAST CONCERNS ARE A COUPLE OF PERIODS OF GALE FORCE WINDS OVER NORTHERN LAKE MICHIGAN THIS AFTERNOON/EVENING...AND AGAIN TUESDAY AND TUESDAY NIGHT ACROSS THE ENTIRE LAKE. HAVE UPGRADED GALE WATCH TO A GALE WARNING FOR TUESDAY AND TUESDAY NIGHT. STRENGTHENING LOW PRESSURE WAS LOCATED JUST NORTH AND NORTHEAST OF LAKE SUPERIOR THIS AFTERNOON...AND WILL CONTINUE TO DEEPEN AS IT LIFTS TOWARD JAMES BAY THIS EVENING. AS THE LOW DEEPENS...A PERIOD OF TIGHTENING SURFACE PRESSURE GRADIENT WAS RESULTING IN LOW-END WEST GALES ACROSS MAINLY NORTHERN LAKE MICHIGAN WITH GRAND TRAVERSE LIGHT GUSTING 34 KTS AS OF NOON CST. GALES WILL LINGER TONIGHT AS THE LOW PULLS AWAY...GRADUALLY EASING AFTER MIDNIGHT ACROSS THE FAR NORTHERN PORTION OF THE LAKE AS WEAK HIGH PRESSURE RIDGING MOVES ACROSS THE WESTERN LAKES. THE LULL LOOKS TO BE BRIEF HOWEVER...AS A FAST MOVING CLIPPER SYSTEM CURRENTLY MOVING ACROSS FAR SOUTHERN SASKATCHEWAN TRAVELS QUICKLY TO THE UPPER MISSISSIPPI VALLEY OVERNIGHT...AND ACROSS THE NORTHERN/WESTERN GREAT LAKES REGION ON TUESDAY. THIS WILL INDUCE A QUICK RE-TIGHTENING OF THE SURFACE PRESSURE GRADIENT ACROSS LAKE MICHIGAN TUESDAY MORNING...WITH STRONG SURFACE-BASED MIXING AND COLD ADVECTION EXPECTED TO PRODUCE WESTERLY 40 KT GALES BASED ON MODEL FORECAST SOUNDINGS. GALES LOOK TO PERSIST INTO TUESDAY EVENING ACROSS THE SOUTH HALF OF THE LAKE...AND PAST MIDNIGHT FARTHER NORTH. HIGH PRESSURE THEN BUILDS SOUTHEAST FROM THE CENTRAL PLAINS THROUGH THE MID/LOWER MISSOURI AND LOWER OHIO RIVER VALLEYS WEDNESDAY AND WEDNESDAY NIGHT...ALLOWING GALES TO EASE THOUGH WINDS REMAIN WESTERLY IN THE 20-30 KT RANGE IN THE TIGHTER GRADIENT NORTH OF THE SURFACE HIGH AND SOUTH OF LOW PRESSURE WHICH LINGERS OVER HUDSON BAY. WEST WINDS WILL LINGER THROUGH THURSDAY AS THE HIGH SPREADS EAST THROUGH THE OHIO VALLEY...AND ANOTHER WEAK LOW CROSSES THE NORTHERN LAKES. IN THE NEAR TERM...SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS THROUGH EARLY TUESDAY... WITH WINDS/WAVES DIMINISHING MORE QUICKLY ALONG THE ILLINOIS SHORE TONIGHT. THE GALE WARNING TUESDAY/TUESDAY EVENING INCLUDES THE NEAR SHORE WATERS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3 AM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 8 AM TUESDAY. GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 AM TUESDAY TO 9 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
303 AM EST TUE DEC 10 2013 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 148 PM EST MON DEC 9 2013 SEVERAL WEAK WEATHER SYSTEMS AFFECT OUR REGION TODAY INTO MIDWEEK WITH MORE SIGNIFICANT SYSTEM FOR THIS WEEKEND. COLD ARCTIC HIGH PRESSURE TO RULE IN BETWEEN WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH EARLY NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 957 PM EST MON DEC 9 2013 FOR THE LATEST UPDATE...TIMING LOOKS PRETTY GOOD AS ECHOES ARE STRENGTHENING OVER SOUTHERN ILLINOIS AND OBSERVATIONS OF LIGHT SNOW ARE BEGINNING TO COME IN FROM THERE. RAP AND HRRR CONTINUE TO SHOW GOOD DEVELOPMENT OVER THE SOUTHWEST BY AROUND 5-6Z. DID DROP SNOWFALL AMOUNTS PRIOR TO 6Z WITH SNOW JUST GETTING GOING THEN. INCREASED VALUES IN THE 6-12Z TIME BASED ON SHORT TERM MODEL OUTPUT. ALSO NOTED IN THE SHORT TERM GUIDANCE WAS A SLIGHT SHIFT SOUTH IN THE MEASURABLE PRECIPITATION...BUT WITH THE SHARP GRADIENT ALREADY IN THE POP GRIDS DID NOT THINK A CHANGE THERE WAS NEEDED. IN SNOW AMOUNTS THOUGH KEPT SIMILAR VALUES AROUND 1.5 INCHES IN THE SOUTH BUT DROPPED THEM IN THE NORTH SO THE TERRE HAUTE TO SOUTH INDY TO RUSHVILLE AREAS SHOULD ONLY SEE A TENTH UP TO A FEW TENTHS OF AN INCH. CONTINUED WITH EARLIER SPS TO HIGHLIGHT SNOWFALL AND SLICK CONDITIONS EXPECTED FOR TUESDAY MORNING COMMUTE. PREVIOUS DISCUSSION FOLLOWS... CONCERN FOR TONIGHT IS SNOW/NO SNOW BOUNDARY AND HOW MUCH SNOW WILL OCCUR. WILL NOT ISSUE ADVISORY FOR THIS BUT MAKE MENTION IN HAZARDOUS WEATHER OUTLOOK AND SPECIAL WEATHER STATEMENT. AS TAIL END OF FIRST WEAK SHORT WAVE EXITS GREAT LAKES THIS AFTERNOON THE SECOND ONE OVER THE TX PANHANDLE REGION BEGINS TO TAKE SHAPE AND AIM ON THE OHIO VALLEY. MODELS IN GOOD AGREEMENT ON RAPID SPREAD OF NARROW SNOW BAND ENE ACROSS SOUTHERN AND CENTRAL INDIANA SOUTH OF I-70 LATE EVENING AND OVERNIGHT...QUICKLY EXITING BEFORE SUNRISE. THOUGH MOISTURE IS SOMEWHAT LIMITED...BRIEF PERIOD OF DENDRITIC GROWTH MAXES OUT OVER SOUTHERN COUNTIES AND WITH RATIOS NEAR 15 TO ONE...EXPECT SNOW AMOUNTS OVER ONE INCH BY DAWN FROM VINCENNES TO BEDFORD-BLOOMINGTON...COLUMBUS AND SEYMOUR. LOCAL TWO INCH AMOUNTS WILL LIKELY OCCUR. THE CUT-OFF FOR NO SNOW WILL BE NEARLY PARALLEL AND JUST A BIT NORTH OF I-70 SO SOUTH SIDE OF INDY METRO COULD SEE HALF INCH WHILE NORTH SIDE GETS JUST A DUSTING. CURRENT FORECAST TEMPS NOT BAD BUT WITH BRIEF PERIOD OF PARTIAL CLEARING THIS EVENING...ESPECIALLY NORTHERN COUNTIES...HAVE ADJUSTED TEMPS DOWN A COUPLE DEGREES BUT STILL 10-18F RANGE NW TO SE. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... ISSUED AT 148 PM EST MON DEC 9 2013 TONIGHT/S SYSTEM WILL BE RAPIDLY EXITING TUESDAY MORNING WITH GUSTY WEST WINDS AND CLEARING SKIES DEVELOPING IN THE MORNING. CURRENT MAX TEMPS IN LINE WITH LATEST DATA AND DESPITE SUNSHINE EXPECT NO BETTER THAN MID TO UPPER 20S. TUESDAY NIGHT...SKIES BEGIN TO CLOUD OVER ACROSS NORTHERN COUNTIES AS CLIPPER SYSTEM AND ARCTIC FRONT SWEEPS INTO WESTERN GREAT LAKES BY DAYBREAK WEDNESDAY. SOUTHERN COUNTIES REMAIN UNDER THE INFLUENCE OF COLD HIGH PRESSURE AND MAINTAIN MOSTLY CLEAR SKIES. EXPECTING SIMILAR LOWS WITH READINGS IN 10 TO 15F RANGE. WEDNESDAY...CURRENTLY LOOKS LIKE THE QUICK CLIPPER SYSTEM/S MEASURABLE SNOWS WOULD REMAIN NORTH OF A LAFAYETTE TO MUNCIE LINE AND EVEN THERE AMOUNTS SHOULD BE NO MORE THAN A DUSTING TO HALF INCH. STRONG ARCTIC HIGH PRESSURE RAPIDLY CLEARS SKIES WEDNESDAY AFTERNOON AND SETS STAGE FOR CLEAR SKY WEDNESDAY NIGHT WITH SINGLE DIGIT LOWS AFTER SLOWLY FALLING TEMPS WEDNESDAY AFTERNOON. HIGH PRESSURE SETTLING INTO THE TENNESSEE VALLEY THURSDAY BRINGS RETURN FLOW TO SOUTHWEST BUT LITTLE MODERATION OF TEMPS UNDER SUNNY SKIES. FORECAST MAX TEMPS UPPER TEENS TO LOWER 20S STILL APPEAR LIKELY. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 303 AM EST TUE DEC 10 2013 FOCUS IN THE LONG TERM REMAINS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE IN DECENT AGREEMENT WITH MOST FEATURES...ALTHOUGH THERE REMAINS SOME DISAGREEMENT ON HOW MUCH COLD AIR MOVES IN ON SUNDAY. WITH THE UNCERTAINTY INVOLVED STAYED CLOSE TO ALLBLEND FOR MOST ITEMS. AN UPPER TROUGH WILL BEGIN ITS APPROACH FRIDAY. MODEL TRENDS HAVE BEEN TO SLOW DOWN THIS FEATURE...SO SLOWED POPS UNTIL FRIDAY AFTERNOON. AS THIS TROUGH MOVES INTO AND THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY NIGHT PRECIPITATION WILL MOVE THROUGH. THUS WENT HIGH CHANCE OR LIKELY POPS FRIDAY NIGHT INTO SATURDAY...WITH LOWERING POPS SATURDAY NIGHT AS THE SYSTEM EXITS. SOME QUESTION ON PATH OF SURFACE LOW AND HOW FAR NORTH WARM AIR WILL GET. THEREFORE WENT SNOW NORTH 2/3 AND RAIN/SNOW SOUTH 1/3 OF THE AREA FRIDAY NIGHT AND SATURDAY. IF LOW GOES FARTHER NORTH PRECIPITATION MAY TURN TO JUST RAIN ACROSS THE FAR SOUTH. SOME AREAS COULD SEE A FEW INCHES OF SNOW AS WELL DEPENDING ON TRACK. SOME COLD ADVECTION AND/OR LAKE EFFECT SNOW SHOWERS MAY IMPACT THE AREA ON SUNDAY SO WENT LOW POPS ACROSS MAINLY THE NORTHEAST FORECAST AREA. ANOTHER POTENTIAL SYSTEM COULD MOVE IN FOR MONDAY...BUT AT THE MOMENT UNCERTAINTY IS TOO HIGH TO MENTION ANY POPS AT THIS TIME. && .AVIATION /DISCUSSION FOR THE 100600Z TAFS/... ISSUED AT 1140 PM EST MON DEC 9 2013 SNOW BEGINNING TO REACH THE GROUND OVER SOUTHWEST INDIANA WITH ASSOCIATED IFR VISIBILITY RESTRICTIONS. LATEST MODEL GUIDANCE SUGGESTS KBMG WILL SEE THE BEST CHANCES FOR IFR RESTRICTIONS IN SNOW OVERNIGHT...WITH LIGHTER SNOW AT KIND/KHUF. APPEARS KLAF WILL NOT BE AFFECTED BY THIS SYSTEM. SYSTEM IS MOVING PRETTY FAST...SO THINK THE SNOW THREAT WILL END AT THE TAF SITES BY 101100Z. CEILINGS GENERALLY NEAR OR ABOVE 050 OVERNIGHT EXCEPT IN THE HEAVIER SNOW AREAS WHERE CEILINGS WILL BE LOWER. LINGERING CEILINGS SHOULD SCATTER OUT AFTER SUNRISE ON TUESDAY. MODEL WIND FIELDS SUGGEST SOME SURFACE GUSTS AROUND 25 KTS FROM 240-260 DEGREES WILL DEVELOP AFTER 101600Z. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TUCEK NEAR TERM...TUCEK/CP SHORT TERM...TUCEK LONG TERM....50 AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1140 PM EST MON DEC 9 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 148 PM EST MON DEC 9 2013 SEVERAL WEAK WEATHER SYSTEMS AFFECT OUR REGION TODAY INTO MIDWEEK WITH MORE SIGNIFICANT SYSTEM FOR THIS WEEKEND. COLD ARCTIC HIGH PRESSURE TO RULE IN BETWEEN WITH TEMPERATURES REMAINING WELL BELOW NORMAL THROUGH EARLY NEXT WEEK. && .NEAR TERM /REST OF TONIGHT/... ISSUED AT 957 PM EST MON DEC 9 2013 FOR THE LATEST UPDATE...TIMING LOOKS PRETTY GOOD AS ECHOES ARE STRENGTHENING OVER SOUTHERN ILLINOIS AND OBSERVATIONS OF LIGHT SNOW ARE BEGINNING TO COME IN FROM THERE. RAP AND HRRR CONTINUE TO SHOW GOOD DEVELOPMENT OVER THE SOUTHWEST BY AROUND 5-6Z. DID DROP SNOWFALL AMOUNTS PRIOR TO 6Z WITH SNOW JUST GETTING GOING THEN. INCREASED VALUES IN THE 6-12Z TIME BASED ON SHORT TERM MODEL OUTPUT. ALSO NOTED IN THE SHORT TERM GUIDANCE WAS A SLIGHT SHIFT SOUTH IN THE MEASURABLE PRECIPITATION...BUT WITH THE SHARP GRADIENT ALREADY IN THE POP GRIDS DID NOT THINK A CHANGE THERE WAS NEEDED. IN SNOW AMOUNTS THOUGH KEPT SIMILAR VALUES AROUND 1.5 INCHES IN THE SOUTH BUT DROPPED THEM IN THE NORTH SO THE TERRE HAUTE TO SOUTH INDY TO RUSHVILLE AREAS SHOULD ONLY SEE A TENTH UP TO A FEW TENTHS OF AN INCH. CONTINUED WITH EARLIER SPS TO HIGHLIGHT SNOWFALL AND SLICK CONDITIONS EXPECTED FOR TUESDAY MORNING COMMUTE. PREVIOUS DISCUSSION FOLLOWS... CONCERN FOR TONIGHT IS SNOW/NO SNOW BOUNDARY AND HOW MUCH SNOW WILL OCCUR. WILL NOT ISSUE ADVISORY FOR THIS BUT MAKE MENTION IN HAZARDOUS WEATHER OUTLOOK AND SPECIAL WEATHER STATEMENT. AS TAIL END OF FIRST WEAK SHORT WAVE EXITS GREAT LAKES THIS AFTERNOON THE SECOND ONE OVER THE TX PANHANDLE REGION BEGINS TO TAKE SHAPE AND AIM ON THE OHIO VALLEY. MODELS IN GOOD AGREEMENT ON RAPID SPREAD OF NARROW SNOW BAND ENE ACROSS SOUTHERN AND CENTRAL INDIANA SOUTH OF I-70 LATE EVENING AND OVERNIGHT...QUICKLY EXITING BEFORE SUNRISE. THOUGH MOISTURE IS SOMEWHAT LIMITED...BRIEF PERIOD OF DENDRITIC GROWTH MAXES OUT OVER SOUTHERN COUNTIES AND WITH RATIOS NEAR 15 TO ONE...EXPECT SNOW AMOUNTS OVER ONE INCH BY DAWN FROM VINCENNES TO BEDFORD-BLOOMINGTON...COLUMBUS AND SEYMOUR. LOCAL TWO INCH AMOUNTS WILL LIKELY OCCUR. THE CUT-OFF FOR NO SNOW WILL BE NEARLY PARALLEL AND JUST A BIT NORTH OF I-70 SO SOUTH SIDE OF INDY METRO COULD SEE HALF INCH WHILE NORTH SIDE GETS JUST A DUSTING. CURRENT FORECAST TEMPS NOT BAD BUT WITH BRIEF PERIOD OF PARTIAL CLEARING THIS EVENING...ESPECIALLY NORTHERN COUNTIES...HAVE ADJUSTED TEMPS DOWN A COUPLE DEGREES BUT STILL 10-18F RANGE NW TO SE. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... ISSUED AT 148 PM EST MON DEC 9 2013 TONIGHT/S SYSTEM WILL BE RAPIDLY EXITING TUESDAY MORNING WITH GUSTY WEST WINDS AND CLEARING SKIES DEVELOPING IN THE MORNING. CURRENT MAX TEMPS IN LINE WITH LATEST DATA AND DESPITE SUNSHINE EXPECT NO BETTER THAN MID TO UPPER 20S. TUESDAY NIGHT...SKIES BEGIN TO CLOUD OVER ACROSS NORTHERN COUNTIES AS CLIPPER SYSTEM AND ARCTIC FRONT SWEEPS INTO WESTERN GREAT LAKES BY DAYBREAK WEDNESDAY. SOUTHERN COUNTIES REMAIN UNDER THE INFLUENCE OF COLD HIGH PRESSURE AND MAINTAIN MOSTLY CLEAR SKIES. EXPECTING SIMILAR LOWS WITH READINGS IN 10 TO 15F RANGE. WEDNESDAY...CURRENTLY LOOKS LIKE THE QUICK CLIPPER SYSTEM/S MEASURABLE SNOWS WOULD REMAIN NORTH OF A LAFAYETTE TO MUNCIE LINE AND EVEN THERE AMOUNTS SHOULD BE NO MORE THAN A DUSTING TO HALF INCH. STRONG ARCTIC HIGH PRESSURE RAPIDLY CLEARS SKIES WEDNESDAY AFTERNOON AND SETS STAGE FOR CLEAR SKY WEDNESDAY NIGHT WITH SINGLE DIGIT LOWS AFTER SLOWLY FALLING TEMPS WEDNESDAY AFTERNOON. HIGH PRESSURE SETTLING INTO THE TENNESSEE VALLEY THURSDAY BRINGS RETURN FLOW TO SOUTHWEST BUT LITTLE MODERATION OF TEMPS UNDER SUNNY SKIES. FORECAST MAX TEMPS UPPER TEENS TO LOWER 20S STILL APPEAR LIKELY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... ISSUED AT 255 PM EST MON DEC 9 2013 MAIN CHALLENGE FOR THE EXTENDED IS THE ARRIVAL AND IMPACT OF ANOTHER POTENTIALLY MESSY WINTRY SYSTEM INTO THE OHIO VALLEY FRIDAY NIGHT AND SATURDAY. UPPER FLOW PATTERN WILL BRIEFLY TRANSITION FROM THE DEEP TROUGH TO MORE OF A BROAD SOUTHWEST FLOW. AN UPPER WAVE WILL EJECT OUT OF NORTHERN MEXICO ON FRIDAY AND QUICKLY TRACK INTO THE OHIO VALLEY BY SATURDAY. A WEAK SURFACE WAVE WILL DEVELOP OVER THE SOUTHERN ROCKIES AND MOVE INTO THE TENNESSEE VALLEY ON SATURDAY. THE MODEL DIFFERENCES DEVELOP WITH RESPECT TO THE TIMING OF THE UPPER WAVE AND THE STRENGTH OF THE SURFACE LOW. OP GFS CONTINUES TO HOLD THE UPPER WAVE FURTHER WEST AND BRINGS A STRONGER SURFACE WAVE INTO THE REGION SATURDAY...WHILE THE GLOBAL MODELS ARE MORE PROGRESSIVE ALOFT WITH A WEAKER SURFACE WAVE TRACKING FURTHER TO THE SOUTH. THE TRACK AND INTENSITY OF THE SURFACE WAVE WILL DETERMINE HOW MUCH WARM AIR WITHIN THE BOUNDARY LAYER CAN BE ADVECTED NORTH INTO THE REGION LATE FRIDAY NIGHT AND SATURDAY. AT THIS POINT...AM LEANING TOWARDS THE COOLER GLOBAL MODELS WHICH LIMIT ANY POTENTIAL MIXING OF PRECIP TO FAR SOUTHERN COUNTIES WHERE CRITICAL LOW LEVEL THICKNESSES RISE TO AROUND 1305M FOR ABOUT 6-12 HOURS. SHOULD THIS COME TO PASS...SOUNDINGS WOULD SUPPORT FREEZING RAIN AS THE PREDOMINANT TYPE LATE FRIDAY NIGHT INTO SATURDAY FOR SEVERAL HOURS. WITH STILL PLENTY OF UNCERTAINTY AT THIS EARLY STAGE...WILL CARRY A RA/SN MIX OVER THE FAR SOUTH WITH SNOW OVER THE REST OF THE AREA. ENOUGH MOISTURE ACCOMPANYING THIS SYSTEM THAT COULD SEE A FEW INCHES OF ACCUM FRIDAY NIGHT/SATURDAY IF PRECIP REMAINS LARGELY IN THE FORM OF SNOW. WILL CERTAINLY BE KEEPING A CLOSE EYE ON THE EVOLUTION OF THIS SYSTEM IN THE DAYS TO COME. BEHIND THE SATURDAY STORM...COLDER AIR WILL ONCE AGAIN RETURN AS THE POLAR VORTEX PINWHEELS THROUGH THE NORTHERN GREAT LAKES. HIGHS IN THE 30S FRIDAY AND SATURDAY WILL FALL BACK INTO THE LOWER 20S BY MONDAY WITH SINGLE DIGIT LOWS RETURNING EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR THE 100600Z TAFS/... ISSUED AT 1140 PM EST MON DEC 9 2013 SNOW BEGINNING TO REACH THE GROUND OVER SOUTHWEST INDIANA WITH ASSOCIATED IFR VISIBILITY RESTRICTIONS. LATEST MODEL GUIDANCE SUGGESTS KBMG WILL SEE THE BEST CHANCES FOR IFR RESTRICTIONS IN SNOW OVERNIGHT...WITH LIGHTER SNOW AT KIND/KHUF. APPEARS KLAF WILL NOT BE AFFECTED BY THIS SYSTEM. SYSTEM IS MOVING PRETTY FAST...SO THINK THE SNOW THREAT WILL END AT THE TAF SITES BY 101100Z. CEILINGS GENERALLY NEAR OR ABOVE 050 OVERNIGHT EXCEPT IN THE HEAVIER SNOW AREAS WHERE CEILINGS WILL BE LOWER. LINGERING CEILINGS SHOULD SCATTER OUT AFTER SUNRISE ON TUESDAY. MODEL WIND FIELDS SUGGEST SOME SURFACE GUSTS AROUND 25 KTS FROM 240-260 DEGREES WILL DEVELOP AFTER 101600Z. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TUCEK NEAR TERM...TUCEK/CP SHORT TERM...TUCEK LONG TERM....RYAN AVIATION...JAS VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
353 AM CST TUE DEC 10 2013 .SHORT TERM /TODAY/... ISSUED AT 353 AM CST TUE DEC 10 2013 MAIN FORECAST CONCERN TODAY IS WITH STRONG WINDS AND LIGHT SNOW POTENTIAL EARLY THIS MORNING AND ADDITIONAL SNOW CHANCES LATE THIS AFTERNOON. LEANED TOWARD A BLEND OF THE HOPWRF/NAM12/RAP THROUGH MIDDAY TODAY...AND THEN NAM12/RAP THIS AFTERNOON. QUICK MOVING SHORTWAVE AND STRONG PV ANOMALY WILL CONTINUE TO INCREASE WINDS THIS MORNING AND PROVIDE A BLOWING SNOW POTENTIAL TO NORTHERN IOWA. LIGHT SNOW IS POSSIBLE THROUGH 12Z/13Z TIME AS SOUNDINGS LOSE ICE INTRODUCTION AND DEEP MOISTURE OVER THE FAR NORTH LATER THIS MORNING. WINDS ATOP THE MIXED LAYER NEAR 40 KNOTS AT MCW AND LIKELY WILL SEE BLSN DUE TO THE FRESH SNOW PACK THROUGH MIDDAY. WINDS DIMINISH SLIGHTLY THIS AFTERNOON AS PRESSURE GRADIENT DECREASES. SHORTWAVE QUICKLY DEPARTS THE STATE BY 15Z AND SHOULD SEE SOME CLEARING LATE THIS MORNING INTO THE EARLY AFTERNOON WITH DRY AIR ADVECTING INTO THE STATE. NEXT SHORTWAVE LOOKS TO FOLLOW A SIMILAR TRACK AND AFFECT NORTHERN IOWA...BUT DIFFERENCE WITH THIS SYSTEM IT HAS MORE MOISTURE AND FORCING. POPS INCREASE RAPIDLY PAST 21Z TODAY ACROSS THE NORTH AS NAM AND RAP CONSISTENT ON BRINGING THIS SHORTWAVE INTO THE REGION A BIT QUICKER. TEMPERATURE TREND TODAY WILL BE TRICKY AS WAA CONTINUES AHEAD OF THE TROUGH AND KEEPS THEM STEADY OR SLOWLY RISING BEFORE CAA TAKES OVER BRIEFLY LATE THIS MORNING. THEN MIXING AND SUNSHINE DOMINATE THIS AFTERNOON WARMING TEMPS AGAIN. .LONG TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 353 AM CST TUE DEC 10 2013 THE PRIMARY FORECAST CONCERN WILL BE EARLY IN THE PERIOD. NEXT SYSTEM WILL ALREADY BE ENTERING NORTHWEST IOWA BY 00Z THIS EVENING WITH A BAND OF SNOW DEVELOPING. THIS BAND OF SNOW WILL BE FOCUSED OVER THE NORTHERN HALF OF THE FORECAST AREA THOUGH SOME LIGHT SNOW MAY FAR ACROSS THE SOUTH AS WELL. THOUGH NOT AS IMPRESSIVE AS SUNDAY...A RELATIVELY GOOD LOW LEVEL DENDRITIC LAYER DEPTH OF AROUND 8 KFT. WHILE FORCING WILL BE SPREAD THROUGHOUT A DEEP LAYER AND WILL RESULT IN AN ARRAY OF FLAKE TYPES...THERE WILL BE A PERIOD OF HIGH SNOW RATIO DENDRITES. WITH LIQUID EQUIVALENT VALUES OF GENERALLY ONE TENTH INCH OR LESS WILL RESULT IN SNOWFALL OF 1 TO 2 INCHES ACROSS THE NORTH WITH A MAX CEILING OF 3 INCHES. A STRONG COLD FRONT WILL SWEEP IN IMMEDIATELY BEHIND THE SNOW AND WILL BRING ANOTHER ARCTIC SURGE AND GUSTY NORTHWEST WINDS BACK TO THE STATE. THE COLD AIR AND INCREASING WINDS WILL PRESENT A COUPLE ISSUES. THE MOST OBVIOUS WILL BE EXPECTED BITTERLY COLD WIND CHILLS OF -20 TO -30 ACROSS FAR NORTHERN PORTIONS LATE TONIGHT AND THROUGH MUCH OF WEDNESDAY MORNING. THE SECOND IS THE STRENGTH OF WINDS AND THE IMPACT ON THE NEWLY FALLEN FLUFFY SNOW AND WHAT WAS ON THE GROUND FROM SUNDAY. HIGHLY EFFICIENT MOMENTUM TRANSFER OF MIXED LAYER WINDS WILL BE PRESENT DUE TO THE STRONG COLD ADVECTION. THIS COMBINED WITH A PERIOD OF GOOD PRESSURE GRADIENT WITH A STRONG PRESSURE RISE COUPLET WILL LEAD TO STRONGER WINDS THAN MODELS CURRENTLY SUGGEST. THESE CONDITIONS SHOULD LEAD TO A PERIOD OF LOW LEVEL BLOWING SNOW WHICH MAY NOT SIGNIFICANTLY REDUCE VISIBILITIES BUT WILL LEAD TO DETERIORATED ROAD CONDITIONS. THE SNOW AND BLOWING SNOW LIKELY WILL NOT MEET WINTER WEATHER ADVISORY CRITERIA ALONG. HOWEVER...THIS LEADS TO A HEADLINE DECISION QUANDARY. WITH A GOOD CERTAINTY ON THE WIND CHILL CRITERIA BEING MET...THE BEST OPTION MAY BE TO PACKAGE EVERYTHING TOGETHER INTO A WINTER WEATHER ADVISORY. WITH IT BEING SECOND PERIOD...WILL ALLOW THE DAY SHIFT ANOTHER LOOK AS THE SYSTEM NEARS. ARCTIC COLD TEMPERATURES CAN BE EXPECTED FOR WEDNESDAY FOLLOWED BY A QUICK DROP IN THE EVENING A HIGH PRESSURE SLIDES THROUGH WITH WARM ADVECTION AND RISING TEMPERATURES AFTER MIDNIGHT. WARMER BUT SEASONABLY COLD FOR THURSDAY. ANOTHER COLD FRONT PASSES THROUGH ON FRIDAY. THERE IS POTENTIAL FOR THE STATE TO BE IMPACTED BY LIGHT SNOW WITH THE BOUNDARY ARRIVING FROM THE NORTH. ALSO MOISTURE STREAMING NORTH FROM THE GULF MAY REACH SOUTHEAST IOWA. THIS PRECIPITATION COULD FOR A WINTRY MIX WITH A WARM NOSE ALOFT NUDGING IN BEFORE THE BOUNDARY PUSHES IT SOUTH AGAIN. SIGNS POINTING TO ANOTHER ARCTIC BLAST AROUND SUNDAY TO END THE PERIOD QUITE COLD. && .AVIATION...10/06Z ISSUED AT 1148 PM CST MON DEC 9 2013 GUSTY WINDS STILL EXPECTED TO PICK UP LATER TONIGHT...WITH AREAS OF BLOWING SNOW. POSSIBILITY OF VSBYS DROPPING TO MVFR AND POSSIBLY IFR AT NORTHERN TAF SITES WHERE WINDS WILL BE STRONGEST TOWARD SUNRISE TUESDAY TO MID MORNING TUESDAY. WINDS DIMINISH TOWARD TUESDAY AFTERNOON...WITH ANOTHER SYSTEM PUSHING INTO THE CWA SPREADING SNOW INTO THE AREA TUESDAY EVENING. HAVE INCLUDED SNOW MENTION AT NORTHERN TAF SITES...WITH BEST CHANCES FOR SNOW AT SOUTHERN TAF SITES JUST BEYOND THE CURRENT TAF FORECAST PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
319 AM EST TUE DEC 10 2013 .SYNOPSIS... A POTENT UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION TODAY. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH THE END OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS WEEEKND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LTST SFC ANALY DEPICT LOPRES IN WRN VA/NC. LOW A SFC REFLECTION OF VORTMAX/RRQ OF 180 KT UPR JET. ASSOCD PCPN HAS RAPIDLY BEEN FILLING IN ACRS THE OH/TN VLYS...AND IS ON THE WRN DOORSTEP ATTM. GDNC IN GOOD AGREEMENT THAT THIS WL BE TRACKING ACRS CWFA...PRIMARILY BTWN 12-18 UTC. THE ARRIVAL OF THIS PCPN WL PROVIDE ENUF MIXING TO ERODE FOG CURRENTLY IN PLACE. A STRIP OF DENSE FOG RESIDES FM CHO-IAD. TRENDS SINCE 04Z INDICATE A SLOW IMPRVMNT HAS BEGUN...AND HV ALLWD DENSE FOG ADVY TO EXPIRE AT 08Z. AFTER THAT...VSBY STILL WONT BE GREAT...AS FOG RESTRICTIONS WL BE REPLACED W/ SNOW RESTRICTIONS. THE FEATURES RESPONSIBLE FOR THE SNOW LOOK TO BE PROGRESSIVE. BUT...LIFT VIGOROUS AND H7-5 F-VECTORS DO POINT TO MESOSCALE BANDING. WHILE MAX LIFT NOT EXACTLY IN DENTRITIC GROWTH ZONE...A THIRD TO HALF INCH LIQ QPF SUGGESTS THAT WRNG CRITERIA THREATENED. CANNOT PLACE EXACTLY WHERE THE BANDS WL SET UP /LTST HRRR AND WRF RUNS SUGGEST CHO-DCA-MTN/...FEEL FAIRLY CONFIDENT THAT LCLLY HIER AMTS PSBL. GFS SUGGESTS THAT THE BAND MAY BE NW OF CURRENT 3-6 INCH FCST STRIPE. CONFIDENCE DIMINISHES TWD EZF AND SRN MD DUE TO LOWER SNW RATIOS AND MDL SNDGS SUGGESTING PL WL MIX IN. BOTH OF THESE FACTORS WL REDUCE SNW TTLS. IN LIGHT OF 00Z GDNC...POTL FOR HIER TTLS...AND NOT CERTAIN BANDS WL BE W/IN PREVIOUS WRNG AREA...HV OPTED TO WIDEN WRNG AREA TO INCL LUA-FDK ON THE NW AND CHO- OMH ON THE SE. TIME FRAME NOT EXTENDED AS GDNC STILL PRETTY INSISTENT THAT SNOW SHUD BE ENDING BY 18Z. MAY EVEN SEE BRIGHTENING SKIES BEFORE SUNSET. ONCE SNOW STARTS...TEMPS CHGG LTL...AND FCST MAXT REFLECTS THAT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... HIPRES BLDS TNGT...WL BE ARND THRU WED NGT. SUBSIDENCE INCREASES RAPIDLY...PROVIDING ONLY A SMALL WINDOW FOR UPSLP SHSN THIS EVNG. OTRW...MOCLR SKIES AND CAA DOMINATE THE PD. TOOK MOS BLEND FOR TEMPS. && .LONG TERM /THURSDAY THROUGH MONDAY/... A LONG WAVE TROUGH SHOULD MOVE OFF THE EAST COAST FRIDAY AS HIGH PRESSURE MOVES TO OUR SOUTH. A SLIGHT RELIEF IN TEMPERATURES IS EXPECTED SATURDAY AS RETURN FLOW BRINGS TEMPS IN THE 40S INTO THE REGION. A COLORADO LOW IS EXPECTED TO FORM MID WEEK AND TRAVEL CLOSE TO THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH THIS TREND AND A WINTRY MIX IS EXPECTED AS IT APPROACHES THE MID ATLANTIC. PTYPE AND TIMING SPECIFICS ARE STILL IN QUESTION. LOW PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... LIFR STILL WIDESPREAD...BUT FOG SHUD BE LIFTING BEFORE DAWN. HWVR...VSBY RESTRICTIONS DUE TO FOG WL BE REPLACED BY RESTRICTIONS DUE TO SNOW. ONSET PRIOR TO 12Z. POOR CONDS WL CONT THRU 18Z. VFR TNGT-FRI UNDER HIPRES. DIMINISHED CIGS/VSBYS PSBL SAT AHD OF THE NEXT SYSTEM TO IMPACT THE RGN. && .MARINE... WNDS BLO 10 KT ATTM. MIXING REMAINS POOR THRU THE DAY. HWVR...AS A DISTURBANCE GLIDES BY...PROVIDING A PD OF SNOW...PERHAPS MIXED W/ PL AND A LTL RA IN THE MID BAY...SOME GDNC SUGGESTING WNDS WL PICK UP. HV NOT FLLWD THAT SOLN ATTM...AND HV CAPPED WNDS AT 15 KT. WL NEED TO MONITOR IN CASE A SCA REQD. IN THE WAKE OF THE LOW...COLD AIR WL STREAM IN...PROVIDING A SETUP FOR MORE FVRBL MIXING. WL KEEP SCA IN PLACE TNGT. WNDS DIMINISH FOR WED UNDER HIPRES...WHICH WL BE ARND THRU FRI. A DISTURBANCE MOVE INTO OVR THE WATERS SAT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR DCZ001. MD...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MDZ003-016>018-501-502. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR MDZ004>007-009>011-013-014. VA...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR VAZ028-055>057-503-504. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR VAZ025>027-029>031-036>040-042-050>054-501-502. WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR WVZ050>053-055-501>506. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR ANZ530>543. && $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...HTS LONG TERM...HAS AVIATION...HTS MARINE...HTS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 AM EST TUE DEC 10 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 426 PM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. ONE SHORTWAVE TROUGH EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING FROM SE SASK TOWARD THE NRN PLAINS. AT THE SFC...A WEAK RIDGE OVER WRN MN SEPARATED LOWS NE OF LAKE SUPERIOR AND OVER NE MONTANA. WSW WINDS ACROSS WRN LAKE SUPERIOR WERE SLOWLY VEERING AS THE SHRTWV ADVANCES THROUGH THE AREA. THE INITIAL DOMINANT BAND THROUGH THE NRN KEWEENAW EARLY THIS AFTERNOON HAD LIFTED BACK TO THE NORTH. HOWEVER...MULTIPLE WIND PARALLEL BANDS INTO THE NRN HALF OF THE KEWEENAW HAVE INTENSIFIED THIS AFTERNOON...AIDED BY THE SHRTWV WHICH HAS BOOSTED INVERSION HEIGHTS TO AROUND 9K FT AS 850 MB TEMPS DROP INTO THE -18C TO -21C RANGE. TONIGHT... THE HIGH RES MODELS WERE IN GOOD AGREEMENT AND SUPPORT UPSTREAM TRENDS OF LOW LEVEL WINDS VEERING THIS EVENING WHICH SHOULD PUSH HEAVY LES BANDS OVER THE KEWEENAW GRADUALLY TO THE SOUTH. HOWEVER...THE SRN EXTENT OF THE LES IS EXPECTED TO REMAIN MAINLY NORTH OF M-38. SLR VALUES MAY BE LIMITED BY THE VERY COLD INCOMING ARCTIC AIRMASS WHICH WILL KEEP THE DGZ BELOW 2K FT. GIVEN THE FAVORABLE LOW LEVEL CONV PERSISTING THROUGH MUCH OF THE EVENING BEFORE WINDS BACK AHEAD OF THE NEXT SHORTWAVE...ADDITIONAL ACCUMULATIONS IN THE 3 TO 6 INCH RANGE ARE LIKELY. BY 12Z...EXPECT THAT THE HEAVIER LES SHOULD LIFT TOWARD EAGLE RIVER AND COPPER HARBOR BEFORE MOVING OFFHSORE TUE MORNING. STRONG WRLY GUSTING TO 35 MPH WILL ALSO CAUSE SIGNIFICANT BLOWING AND DRIFTING IN OPEN AREAS WITH VSBY AOB 1/4SM IN THE HEAVIER LES BANDS BEFORE TAPER OFF AFTER 03Z/TUE. TEMPERATURES DROPPING INTO THE ZERO TO 10 BELOW RANGE WITH WINDS OF 10 TO 15 MPH MAY DROP WIND CHILL VALUES TO 15 BELOW TO 25 BELOW THIS EVENING. HOWEVER...WINDS ARE EXPECTED TO DIMINISH TO 7 MPH OR LESS OVER THE COLDER INLAND AREAS...KEEPING WIND CHILLS FROM REACHING ADVISORY THRESHOLD. IN ADDITION...CLOUDS WILL THICKEN LATE AS THE SHRTWV APPROACHES BRINGING SLOWLY CLIMBING TEMPS LATE. TUESDAY... THE SASK SHRTWV WILL MOVE THROUGH THE REGION WITH MODERATE TO STRONG 700-300 MB QVECTOR CONV. EVEN THOUGH THE STRONGEST FORCING IS EXPECTED JUST TO THE SOUTH OF UPPER MICHIGAN...IT SHOULD STILL BE STRONG ENOUGH OVER UPPER MI TO SQUEEZE OUT SOME LIGHT SNOW WITH A FEW HUNDREDTHS QPF IN THE VERY DRY AIRMASS. OVERALL ACCUMULATIONS SHOULD REMAIN BELOW A HALF INCH BUT SHOULD BE WIDESPREAD ENOUGH TO INCLUDE LIKELY POPS. VEERING WINDS IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. ANOTHER PERIOD OF HEAVIER LES IS EXPECTED WITH THIS FEATURE THAT COULD PRODUCE 2 TO 4 INCHES OF SNOW. SINCE THERE IS A GAP BETWEEN THE MON NIGHT LES AND THE NEXT BATCH THE HEADLINE WAS NOT EXTENDED AT THIS TIME. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 416 PM EST MON DEC 9 2013 COLD TEMPERATURES AND LAKE EFFECT SNOW WILL DOMINATE MUCH OF THE LONG TERM FORECAST. A SHORTWAVE AND WEAK LOW PRESSURE SYSTEM SLIDING ACROSS NORTHERN WISCONSIN AND SOUTHERN UPPER MICHIGAN TONIGHT INTO TUESDAY MORNING WILL PROVIDE A REINFORCING SHOT OF COLD AIR TO THE AREA FOR TUESDAY NIGHT INTO WEDNESDAY. MEANWHILE...HIGH PRESSURE WILL BEGIN TO BUILD INTO THE NORTHERN PLAINS BEFORE SINKING SOUTHEAST INTO THE MID MISSISSIPPI VALLEY FOR WEDNESDAY NIGHT. MODELS ARE FAIRLY CONSISTENT ON A SURFACE TROUGH LINGERING OVER CENTRAL/EASTERN LAKE SUPERIOR ON THE BACK SIDE OF THE LOW TUESDAY EVENING AND THEN SHIFTING SOUTHEAST WEDNESDAY MORNING. THIS LINGERING TROUGH WILL LIKELY LEAD TO A LAKE INDUCED LOW DEVELOPING OVER THE FAR EASTERN LAKE WEDNESDAY NIGHT AND REMAINING INTO THURSDAY AS A HIGH PRESSURE RIDGE MOVES OVER SOUTHERN UPPER MICHIGAN. OVERALL...CONDITIONS CONTINUE TO BE VERY FAVORABLE FOR LAKE EFFECT SNOWFALL INTO THURSDAY...WITH 850MB TEMPS FALLING FROM AROUND -21C AT 00Z WEDNESDAY TO -24C ON WEDNESDAY AFTERNOON. THIS STRONG OVER LAKE INSTABILITY (LAKE TEMPS AROUND 2-3C) WILL LEAD TO FAIRLY HIGH EQUILIBRIUM LEVELS (12/15KFT WEST/EAST) AND LAKE INDUCED CAPE VALUES EXCEEDING 800-1000J/KG FOR TUESDAY NIGHT INTO WEDNESDAY. LES WILL BE AIDED ON TUESDAY NIGHT BY LINGERING MOISTURE FROM THE CLIPPER SYSTEM...ALLOWING THE STRONGER BANDS TO REALIZE THE HIGHER INVERSION HEIGHTS. BUT AS THAT DEEPER MOISTURE DEPARTS THROUGH THE NIGHT AND INTO WEDNESDAY MORNING...EXPECT A TRANSITION TO PURE LAKE EFFECT AND THE LOSS OF THE DEEPER MOISTURE MAY LIMIT THE WEAKER BANDS FROM REACHING THE HIGHER INVERSION HEIGHTS. LAKE EFFECT SNOW PARAMETER REALLY HIGHLIGHTS LUCE COUNTY FOR TUESDAY NIGHT INTO WEDNESDAY MORNING...BEFORE VALUES BEGIN TO FALL TO MORE MODERATE LAKE EFFECT VALUES DURING THE DAY AS THE 850MB TEMPERATURES COOL. THE REST OF THE AREA LOOKS TO SEE LOW END MODERATE VALUES DUE TO THE AMOUNT OF COLD AIR. AS FOR SNOW RATIOS...HAVE GENERALLY KEPT VALUES AROUND 20-1 AT THIS POINT...SINCE MUCH OF THE FORCING WILL BE AT THE HIGH END OR ABOVE THE DGZ. THINK THE HIGHEST RATIOS WILL BE INITIALLY TUESDAY NIGHT BEFORE THE COLDER AIR ARRIVES AND SHOVES THE DGZ TOWARDS THE SURFACE. THOSE HIGHER RATIOS MAY BE LIMITED SOMEWHAT BY STRONGER WINDS RIGHT BEHIND THE FRONT LEADING TO FRACTURING OF THE DENDRITES TO GO ALONG WITH MAINLY COLUMNS. BUT THOSE WINDS SHOULD WEAKEN SLIGHTLY INTO WEDNESDAY AND ALLOW THE LIMITED DENDRITES TO REMAIN TOGETHER. WITH CONDITIONS APPEARING GOOD FOR LES...WINDS WILL DETERMINE THE BAND PLACEMENT. EXPECT THE LAKE EFFECT TO BE IN THE WESTERLY FLOW AREAS TO START THE LONG TERM PERIOD...BUT AS THE SURFACE TROUGH DIVES SOUTHEAST...EXPECT BANDS TO SHIFT SOUTH AND SETUP IN THE MORE WEST-NORTHWEST TO NORTHWEST WIND LOCATIONS BY WEDNESDAY MORNING. EXPECT THE HEAVIEST SNOW OVER NORTHERN LUCE COUNTY WHERE THERE WILL BE INCREASED CONVERGENCE FROM THE TROUGH AND HAVE THE LONGEST FETCH ACROSS THE LAKE. SOME DIFFERENCES IN THE TIMING THAT THE DOMINATE BAND MOVES SOUTH INTO NORTHERN LUCE COUNTY...BUT LOOKS TO BE THROUGH THE EVENING HOURS AND THEN REMAINING THROUGH MUCH OF WEDNESDAY AND WEDNESDAY NIGHT BEFORE FINALLY SHIFTING NORTH ON THURSDAY DUE TO A RIDGE MOVING INTO THE SOUTHERN U.P. WITH THE POTENTIAL FOR HEAVY SNOW AND A PROLONGED EVENT (CURRENT FORECAST OF 1-2FT IN FAR NE LUCE COUNTY BY THURSDAY MORNING)...OPTED TO ISSUE A LAKE EFFECT SNOW WATCH FOR LUCE COUNTY. ALGER COUNTY IS A LITTLE MORE UNCERTAIN...AS IT DEPENDS ON HOW FAR SOUTHWEST THE BAND SINKS. BEST OPPORTUNITY WOULD BE NEAR GRAND MARAIS. NAM IS MOST AGGRESSIVE WITH THE SOUTHWEST PUSH...WHILE MOST OF THE OTHER MODELS KEEP WINDS OUT OF THE WNW TO WESTERLY DIRECTION. THUS...HAVE LEFT THEM OUT OF ANY PRODUCTS AT THIS TIME AND HOPEFULLY WE/LL BE ABLE TO PIN DOWN THE SOUTHWEST EXTENT IN THE NEXT 24HRS. FARTHER WEST...EXPECT THE HEAVIEST SNOW IN THE WNW FAVORED AREAS FROM ONTONAGON THROUGH THE KEWEENAW. WITH HE SURFACE TROUGH LIKELY SETUP ACROSS ONTONAGON COUNTY...WOULD EXPECT THERE TO BE SOME SORT OF DOMINATE BAND AND THE HIGHEST SNOWFALL AMOUNTS THERE. AT THIS POINT...HAVE AMOUNTS AN INCH OR TWO UNDER WARNING CRITERIA AND WILL NOT ISSUE A WATCH. SHOULD BE A SOLID ADVISORY AND THERE IS THE POTENTIAL FOR SOME LOCATIONS TO REACH WARNING AMOUNTS. OTHERWISE...EXPECT GENERAL MODERATE LAKE EFFECT SNOW NORTH OF THE TROUGH OVER THE KEWEENAW WITH ADVISORY CRITERIA ACCUMULATIONS. SINCE THERE IS A WARNING OUT FOR THOSE AREAS...WILL HOLD OFF NOW AND LET MID SHIFT PUT UP ADVISORIES ALL AT ONCE. WITH THE HIGH MOVING INTO THE MID MISSISSIPPI VALLEY AND A RIDGE SLIDING INTO SOUTHERN UPPER MICHIGAN LATE WEDNESDAY AFTERNOON AND THROUGH THE NIGHT...EXPECT WINDS TO BACK TO MORE OF A WESTERLY (OR EVEN SOUTHWESTERLY DIRECTION OVER WESTERN LAKE SUPERIOR). THIS WILL PUSH THE LAKE EFFECT SNOW BACK TO THE NORTH THROUGH THE NIGHT AND INTO THURSDAY. THE FOCUS WILL REMAIN OVER THE KEWEENAW AND THE FAR NORTHEAST PART OF LUCE COUNTY DURING THAT TIME. INVERSION HEIGHTS DO LOOK TO LOWER DURING THIS PERIOD TO 5-7KFT...SO WOULD EXPECT THE INTENSITY AND AMOUNTS TO DIMINISH AS THE DGZ LOWERS TO THE SURFACE. FINALLY...ANOTHER WEAK CLIPPER LOOKS TO MOVE THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BUT WILL LIKELY BE SOUTH THAN THE ONE TONIGHT AND MOVE THROUGH CENTRAL/SOUTHERN WISCONSIN. IN ADDITION TO THE LAKE EFFECT SNOW...COLD TEMPERATURES WILL REMAIN OVER THE AREA THROUGH THURSDAY...WHICH WILL LEAD TO SOME CONCERNS FOR WIND CHILL ADVISORIES ON TUESDAY/WEDNESDAY NIGHT. OVERNIGHT LOWS WILL BE IN THE SINGLE DIGITS BELOW ZERO ON TUESDAY NIGHT AND THEN POTENTIALLY 10 DEGREES COLDER ON WEDNESDAY NIGHT. THERE IS SOME CONCERN FOR CLOUDS AHEAD OF THE CLIPPER SYSTEM ON WEDNESDAY NIGHT...WHICH COULD LEAD TO SOME RISING TEMPERATURES TOWARDS MORNING. WIND CHILLS WILL DEPEND ON HOW MUCH DECOUPLING WILL OCCUR AND TUESDAY NIGHT WILL LIKELY SEE WINDS STAYING UP MORE WITH THE TIGHT GRADIENT BETWEEN THE HIGH MOVING INTO THE NORTHERN PLAINS AND THE TROUGH OVER EASTERN LAKE SUPERIOR. THIS WILL PRODUCE WIND CHILL VALUES IN THE -20S OVER THE INTERIOR WEST AND A DECENT CHANCE OF A WIND CHILL ADVISORY. ON WEDNESDAY NIGHT THE SURFACE RIDGE WILL BE MOVING IN AND LEADING TO LIGHT WINDS OVERNIGHT. THESE LIGHT WINDS WILL ALLOW FOR LOWER TEMPS (IF THE CLOUDS STAY TO THE SOUTHWEST) BUT ALSO LIMIT WIND CHILL VALUES...BUT STILL EXPECT THEM IN THE -25 TO -34 DEGREE F RANGE. FOR FRIDAY TO NEXT MONDAY...THE GENERAL TREND IN THE MODELS IS FOR THE UPPER TROUGH TO SHIFT EAST THURSDAY NIGHT AND FRIDAY...LEADING TO SOME MODERATION OF THE COLDER AIR AS THE FLOW ALOFT BECOMES WESTERLY. THEN...AS THE SOUTHERN STREAM TROUGH MOVES INTO THE SOUTHEAST CONUS THIS WEEKEND...ANOTHER STRONG SHORTWAVE WILL DIVE SOUTHEAST IN THE NORTHERN STREAM AND LEAD TO ANOTHER PERIOD OF COLD WEATHER FOR SUNDAY AND THE START OF NEXT WEEK. MODELS STILL VARY ON THE EXACT SOLUTION AND TIMING AS THE DISTURBANCES PHASE OVER THE EASTERN CONUS...BUT THE GENERAL IDEA IS A SURFACE TROUGH SETTING UP OVER THE UPPER GREAT LAKES (STRETCHING NORTHWEST FROM THE LOW MOVING UP THE EAST COAST) FOR MUCH OF THE WEEKEND BEFORE DIVING SOUTHEAST ON SUNDAY NIGHT AND MONDAY WITH THE NORTHERN STREAM SHORTWAVE. MOISTURE ASSOCIATED WITH THE TROUGH... 850MB TEMPS AROUND -22C AND LIKELY LIGHT NORTHERLY WINDS SUPPORTS HAVING SLIGHT/CHANCE POPS OVER MUCH OF THE AREA...ESPECIALLY IN THE NORTH TO NORTHEAST FAVORED LOCATIONS NEAR LAKE SUPERIOR. THIS NORTHERLY FLOW WILL LIKELY LEAD TO SOME LES FOR AREAS THAT HAVE BEEN MISSED BY THE LES AT THE END OF LAST WEEK AND THIS WEEK. SINCE THERE IS CONSISTENCY IN THE MODELS THIS WEEKEND...WILL TREND POPS UP IN THE NORTHERLY WIND AREAS FRIDAY NIGHT INTO SUNDAY AND BEGIN TO HIGHLIGHT IN THE HWO/EHWO. HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES ON MONDAY AFTERNOON...ALTHOUGH THERE ARE HINTS OF ANOTHER SHORTWAVE DIVING INTO THE UPPER MISSISSIPPI VALLEY FOR MONDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1239 AM EST TUE DEC 10 2013 KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE FROM THE NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST PERIOD. KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AND THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE THROUGH TUE EVENING. KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 426 PM EST MON DEC 9 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH MOVING THROUGH LATE THIS AFTERNOON WILL BRING WRLY GALES OF 35 TO 40 KNOTS ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND COULD PRODUCE GALE FORCE WIND GUSTS TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ001- 003. LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH THURSDAY MORNING FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ245-248>251-265>267. GALE WARNING UNTIL 1 AM EST EARLY THIS MORNING FOR LSZ244-245- 248>251-264>267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162-240>244-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1153 PM EST MON DEC 9 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 426 PM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. ONE SHORTWAVE TROUGH EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING FROM SE SASK TOWARD THE NRN PLAINS. AT THE SFC...A WEAK RIDGE OVER WRN MN SEPARATED LOWS NE OF LAKE SUPERIOR AND OVER NE MONTANA. WSW WINDS ACROSS WRN LAKE SUPERIOR WERE SLOWLY VEERING AS THE SHRTWV ADVANCES THROUGH THE AREA. THE INITIAL DOMINANT BAND THROUGH THE NRN KEWEENAW EARLY THIS AFTERNOON HAD LIFTED BACK TO THE NORTH. HOWEVER...MULTIPLE WIND PARALLEL BANDS INTO THE NRN HALF OF THE KEWEENAW HAVE INTENSIFIED THIS AFTERNOON...AIDED BY THE SHRTWV WHICH HAS BOOSTED INVERSION HEIGHTS TO AROUND 9K FT AS 850 MB TEMPS DROP INTO THE -18C TO -21C RANGE. TONIGHT... THE HIGH RES MODELS WERE IN GOOD AGREEMENT AND SUPPORT UPSTREAM TRENDS OF LOW LEVEL WINDS VEERING THIS EVENING WHICH SHOULD PUSH HEAVY LES BANDS OVER THE KEWEENAW GRADUALLY TO THE SOUTH. HOWEVER...THE SRN EXTENT OF THE LES IS EXPECTED TO REMAIN MAINLY NORTH OF M-38. SLR VALUES MAY BE LIMITED BY THE VERY COLD INCOMING ARCTIC AIRMASS WHICH WILL KEEP THE DGZ BELOW 2K FT. GIVEN THE FAVORABLE LOW LEVEL CONV PERSISTING THROUGH MUCH OF THE EVENING BEFORE WINDS BACK AHEAD OF THE NEXT SHORTWAVE...ADDITIONAL ACCUMULATIONS IN THE 3 TO 6 INCH RANGE ARE LIKELY. BY 12Z...EXPECT THAT THE HEAVIER LES SHOULD LIFT TOWARD EAGLE RIVER AND COPPER HARBOR BEFORE MOVING OFFHSORE TUE MORNING. STRONG WRLY GUSTING TO 35 MPH WILL ALSO CAUSE SIGNIFICANT BLOWING AND DRIFTING IN OPEN AREAS WITH VSBY AOB 1/4SM IN THE HEAVIER LES BANDS BEFORE TAPER OFF AFTER 03Z/TUE. TEMPERATURES DROPPING INTO THE ZERO TO 10 BELOW RANGE WITH WINDS OF 10 TO 15 MPH MAY DROP WIND CHILL VALUES TO 15 BELOW TO 25 BELOW THIS EVENING. HOWEVER...WINDS ARE EXPECTED TO DIMINISH TO 7 MPH OR LESS OVER THE COLDER INLAND AREAS...KEEPING WIND CHILLS FROM REACHING ADVISORY THRESHOLD. IN ADDITION...CLOUDS WILL THICKEN LATE AS THE SHRTWV APPROACHES BRINGING SLOWLY CLIMBING TEMPS LATE. TUESDAY... THE SASK SHRTWV WILL MOVE THROUGH THE REGION WITH MODERATE TO STRONG 700-300 MB QVECTOR CONV. EVEN THOUGH THE STRONGEST FORCING IS EXPECTED JUST TO THE SOUTH OF UPPER MICHIGAN...IT SHOULD STILL BE STRONG ENOUGH OVER UPPER MI TO SQUEEZE OUT SOME LIGHT SNOW WITH A FEW HUNDREDTHS QPF IN THE VERY DRY AIRMASS. OVERALL ACCUMULATIONS SHOULD REMAIN BELOW A HALF INCH BUT SHOULD BE WIDESPREAD ENOUGH TO INCLUDE LIKELY POPS. VEERING WINDS IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. ANOTHER PERIOD OF HEAVIER LES IS EXPECTED WITH THIS FEATURE THAT COULD PRODUCE 2 TO 4 INCHES OF SNOW. SINCE THERE IS A GAP BETWEEN THE MON NIGHT LES AND THE NEXT BATCH THE HEADLINE WAS NOT EXTENDED AT THIS TIME. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 416 PM EST MON DEC 9 2013 COLD TEMPERATURES AND LAKE EFFECT SNOW WILL DOMINATE MUCH OF THE LONG TERM FORECAST. A SHORTWAVE AND WEAK LOW PRESSURE SYSTEM SLIDING ACROSS NORTHERN WISCONSIN AND SOUTHERN UPPER MICHIGAN TONIGHT INTO TUESDAY MORNING WILL PROVIDE A REINFORCING SHOT OF COLD AIR TO THE AREA FOR TUESDAY NIGHT INTO WEDNESDAY. MEANWHILE...HIGH PRESSURE WILL BEGIN TO BUILD INTO THE NORTHERN PLAINS BEFORE SINKING SOUTHEAST INTO THE MID MISSISSIPPI VALLEY FOR WEDNESDAY NIGHT. MODELS ARE FAIRLY CONSISTENT ON A SURFACE TROUGH LINGERING OVER CENTRAL/EASTERN LAKE SUPERIOR ON THE BACK SIDE OF THE LOW TUESDAY EVENING AND THEN SHIFTING SOUTHEAST WEDNESDAY MORNING. THIS LINGERING TROUGH WILL LIKELY LEAD TO A LAKE INDUCED LOW DEVELOPING OVER THE FAR EASTERN LAKE WEDNESDAY NIGHT AND REMAINING INTO THURSDAY AS A HIGH PRESSURE RIDGE MOVES OVER SOUTHERN UPPER MICHIGAN. OVERALL...CONDITIONS CONTINUE TO BE VERY FAVORABLE FOR LAKE EFFECT SNOWFALL INTO THURSDAY...WITH 850MB TEMPS FALLING FROM AROUND -21C AT 00Z WEDNESDAY TO -24C ON WEDNESDAY AFTERNOON. THIS STRONG OVER LAKE INSTABILITY (LAKE TEMPS AROUND 2-3C) WILL LEAD TO FAIRLY HIGH EQUILIBRIUM LEVELS (12/15KFT WEST/EAST) AND LAKE INDUCED CAPE VALUES EXCEEDING 800-1000J/KG FOR TUESDAY NIGHT INTO WEDNESDAY. LES WILL BE AIDED ON TUESDAY NIGHT BY LINGERING MOISTURE FROM THE CLIPPER SYSTEM...ALLOWING THE STRONGER BANDS TO REALIZE THE HIGHER INVERSION HEIGHTS. BUT AS THAT DEEPER MOISTURE DEPARTS THROUGH THE NIGHT AND INTO WEDNESDAY MORNING...EXPECT A TRANSITION TO PURE LAKE EFFECT AND THE LOSS OF THE DEEPER MOISTURE MAY LIMIT THE WEAKER BANDS FROM REACHING THE HIGHER INVERSION HEIGHTS. LAKE EFFECT SNOW PARAMETER REALLY HIGHLIGHTS LUCE COUNTY FOR TUESDAY NIGHT INTO WEDNESDAY MORNING...BEFORE VALUES BEGIN TO FALL TO MORE MODERATE LAKE EFFECT VALUES DURING THE DAY AS THE 850MB TEMPERATURES COOL. THE REST OF THE AREA LOOKS TO SEE LOW END MODERATE VALUES DUE TO THE AMOUNT OF COLD AIR. AS FOR SNOW RATIOS...HAVE GENERALLY KEPT VALUES AROUND 20-1 AT THIS POINT...SINCE MUCH OF THE FORCING WILL BE AT THE HIGH END OR ABOVE THE DGZ. THINK THE HIGHEST RATIOS WILL BE INITIALLY TUESDAY NIGHT BEFORE THE COLDER AIR ARRIVES AND SHOVES THE DGZ TOWARDS THE SURFACE. THOSE HIGHER RATIOS MAY BE LIMITED SOMEWHAT BY STRONGER WINDS RIGHT BEHIND THE FRONT LEADING TO FRACTURING OF THE DENDRITES TO GO ALONG WITH MAINLY COLUMNS. BUT THOSE WINDS SHOULD WEAKEN SLIGHTLY INTO WEDNESDAY AND ALLOW THE LIMITED DENDRITES TO REMAIN TOGETHER. WITH CONDITIONS APPEARING GOOD FOR LES...WINDS WILL DETERMINE THE BAND PLACEMENT. EXPECT THE LAKE EFFECT TO BE IN THE WESTERLY FLOW AREAS TO START THE LONG TERM PERIOD...BUT AS THE SURFACE TROUGH DIVES SOUTHEAST...EXPECT BANDS TO SHIFT SOUTH AND SETUP IN THE MORE WEST-NORTHWEST TO NORTHWEST WIND LOCATIONS BY WEDNESDAY MORNING. EXPECT THE HEAVIEST SNOW OVER NORTHERN LUCE COUNTY WHERE THERE WILL BE INCREASED CONVERGENCE FROM THE TROUGH AND HAVE THE LONGEST FETCH ACROSS THE LAKE. SOME DIFFERENCES IN THE TIMING THAT THE DOMINATE BAND MOVES SOUTH INTO NORTHERN LUCE COUNTY...BUT LOOKS TO BE THROUGH THE EVENING HOURS AND THEN REMAINING THROUGH MUCH OF WEDNESDAY AND WEDNESDAY NIGHT BEFORE FINALLY SHIFTING NORTH ON THURSDAY DUE TO A RIDGE MOVING INTO THE SOUTHERN U.P. WITH THE POTENTIAL FOR HEAVY SNOW AND A PROLONGED EVENT (CURRENT FORECAST OF 1-2FT IN FAR NE LUCE COUNTY BY THURSDAY MORNING)...OPTED TO ISSUE A LAKE EFFECT SNOW WATCH FOR LUCE COUNTY. ALGER COUNTY IS A LITTLE MORE UNCERTAIN...AS IT DEPENDS ON HOW FAR SOUTHWEST THE BAND SINKS. BEST OPPORTUNITY WOULD BE NEAR GRAND MARAIS. NAM IS MOST AGGRESSIVE WITH THE SOUTHWEST PUSH...WHILE MOST OF THE OTHER MODELS KEEP WINDS OUT OF THE WNW TO WESTERLY DIRECTION. THUS...HAVE LEFT THEM OUT OF ANY PRODUCTS AT THIS TIME AND HOPEFULLY WE/LL BE ABLE TO PIN DOWN THE SOUTHWEST EXTENT IN THE NEXT 24HRS. FARTHER WEST...EXPECT THE HEAVIEST SNOW IN THE WNW FAVORED AREAS FROM ONTONAGON THROUGH THE KEWEENAW. WITH HE SURFACE TROUGH LIKELY SETUP ACROSS ONTONAGON COUNTY...WOULD EXPECT THERE TO BE SOME SORT OF DOMINATE BAND AND THE HIGHEST SNOWFALL AMOUNTS THERE. AT THIS POINT...HAVE AMOUNTS AN INCH OR TWO UNDER WARNING CRITERIA AND WILL NOT ISSUE A WATCH. SHOULD BE A SOLID ADVISORY AND THERE IS THE POTENTIAL FOR SOME LOCATIONS TO REACH WARNING AMOUNTS. OTHERWISE...EXPECT GENERAL MODERATE LAKE EFFECT SNOW NORTH OF THE TROUGH OVER THE KEWEENAW WITH ADVISORY CRITERIA ACCUMULATIONS. SINCE THERE IS A WARNING OUT FOR THOSE AREAS...WILL HOLD OFF NOW AND LET MID SHIFT PUT UP ADVISORIES ALL AT ONCE. WITH THE HIGH MOVING INTO THE MID MISSISSIPPI VALLEY AND A RIDGE SLIDING INTO SOUTHERN UPPER MICHIGAN LATE WEDNESDAY AFTERNOON AND THROUGH THE NIGHT...EXPECT WINDS TO BACK TO MORE OF A WESTERLY (OR EVEN SOUTHWESTERLY DIRECTION OVER WESTERN LAKE SUPERIOR). THIS WILL PUSH THE LAKE EFFECT SNOW BACK TO THE NORTH THROUGH THE NIGHT AND INTO THURSDAY. THE FOCUS WILL REMAIN OVER THE KEWEENAW AND THE FAR NORTHEAST PART OF LUCE COUNTY DURING THAT TIME. INVERSION HEIGHTS DO LOOK TO LOWER DURING THIS PERIOD TO 5-7KFT...SO WOULD EXPECT THE INTENSITY AND AMOUNTS TO DIMINISH AS THE DGZ LOWERS TO THE SURFACE. FINALLY...ANOTHER WEAK CLIPPER LOOKS TO MOVE THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BUT WILL LIKELY BE SOUTH THAN THE ONE TONIGHT AND MOVE THROUGH CENTRAL/SOUTHERN WISCONSIN. IN ADDITION TO THE LAKE EFFECT SNOW...COLD TEMPERATURES WILL REMAIN OVER THE AREA THROUGH THURSDAY...WHICH WILL LEAD TO SOME CONCERNS FOR WIND CHILL ADVISORIES ON TUESDAY/WEDNESDAY NIGHT. OVERNIGHT LOWS WILL BE IN THE SINGLE DIGITS BELOW ZERO ON TUESDAY NIGHT AND THEN POTENTIALLY 10 DEGREES COLDER ON WEDNESDAY NIGHT. THERE IS SOME CONCERN FOR CLOUDS AHEAD OF THE CLIPPER SYSTEM ON WEDNESDAY NIGHT...WHICH COULD LEAD TO SOME RISING TEMPERATURES TOWARDS MORNING. WIND CHILLS WILL DEPEND ON HOW MUCH DECOUPLING WILL OCCUR AND TUESDAY NIGHT WILL LIKELY SEE WINDS STAYING UP MORE WITH THE TIGHT GRADIENT BETWEEN THE HIGH MOVING INTO THE NORTHERN PLAINS AND THE TROUGH OVER EASTERN LAKE SUPERIOR. THIS WILL PRODUCE WIND CHILL VALUES IN THE -20S OVER THE INTERIOR WEST AND A DECENT CHANCE OF A WIND CHILL ADVISORY. ON WEDNESDAY NIGHT THE SURFACE RIDGE WILL BE MOVING IN AND LEADING TO LIGHT WINDS OVERNIGHT. THESE LIGHT WINDS WILL ALLOW FOR LOWER TEMPS (IF THE CLOUDS STAY TO THE SOUTHWEST) BUT ALSO LIMIT WIND CHILL VALUES...BUT STILL EXPECT THEM IN THE -25 TO -34 DEGREE F RANGE. FOR FRIDAY TO NEXT MONDAY...THE GENERAL TREND IN THE MODELS IS FOR THE UPPER TROUGH TO SHIFT EAST THURSDAY NIGHT AND FRIDAY...LEADING TO SOME MODERATION OF THE COLDER AIR AS THE FLOW ALOFT BECOMES WESTERLY. THEN...AS THE SOUTHERN STREAM TROUGH MOVES INTO THE SOUTHEAST CONUS THIS WEEKEND...ANOTHER STRONG SHORTWAVE WILL DIVE SOUTHEAST IN THE NORTHERN STREAM AND LEAD TO ANOTHER PERIOD OF COLD WEATHER FOR SUNDAY AND THE START OF NEXT WEEK. MODELS STILL VARY ON THE EXACT SOLUTION AND TIMING AS THE DISTURBANCES PHASE OVER THE EASTERN CONUS...BUT THE GENERAL IDEA IS A SURFACE TROUGH SETTING UP OVER THE UPPER GREAT LAKES (STRETCHING NORTHWEST FROM THE LOW MOVING UP THE EAST COAST) FOR MUCH OF THE WEEKEND BEFORE DIVING SOUTHEAST ON SUNDAY NIGHT AND MONDAY WITH THE NORTHERN STREAM SHORTWAVE. MOISTURE ASSOCIATED WITH THE TROUGH... 850MB TEMPS AROUND -22C AND LIKELY LIGHT NORTHERLY WINDS SUPPORTS HAVING SLIGHT/CHANCE POPS OVER MUCH OF THE AREA...ESPECIALLY IN THE NORTH TO NORTHEAST FAVORED LOCATIONS NEAR LAKE SUPERIOR. THIS NORTHERLY FLOW WILL LIKELY LEAD TO SOME LES FOR AREAS THAT HAVE BEEN MISSED BY THE LES AT THE END OF LAST WEEK AND THIS WEEK. SINCE THERE IS CONSISTENCY IN THE MODELS THIS WEEKEND...WILL TREND POPS UP IN THE NORTHERLY WIND AREAS FRIDAY NIGHT INTO SUNDAY AND BEGIN TO HIGHLIGHT IN THE HWO/EHWO. HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES ON MONDAY AFTERNOON...ALTHOUGH THERE ARE HINTS OF ANOTHER SHORTWAVE DIVING INTO THE UPPER MISSISSIPPI VALLEY FOR MONDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1153 PM EST MON DEC 9 2013 KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE THE NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST PERIOD. KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE THROUGH TUE EVENING. KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 426 PM EST MON DEC 9 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH MOVING THROUGH LATE THIS AFTERNOON WILL BRING WRLY GALES OF 35 TO 40 KNOTS ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND COULD PRODUCE GALE FORCE WIND GUSTS TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE EFFECT SNOW WATCH FROM TUESDAY EVENING THROUGH THURSDAY MORNING FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST TUESDAY FOR LSZ245- 248>251-265>267. GALE WARNING UNTIL 1 AM EST TUESDAY FOR LSZ244-245-248>251- 264>267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264. GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
434 AM EST TUE DEC 10 2013 .SYNOPSIS... WEAK SYSTEM EARLY TODAY WITH SOME SNOW. CHILLY DRY HIGH PRESSURE WEDNESDAY. ARCTIC FRONT WEDNESDAY NIGHT. ARCTIC HIGH PRESSURE THURSDAY EXITS FRIDAY. ANOTHER SYSTEM THIS WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 1230 AM UPDATE... FORECAST ESSENTIALLY ON TRACK AT THIS POINT. ONE FORECASTED BAND OF SNOW LOCATED OUT TO OUR WEST OVER CENTRAL/SW OHIO STILL PROGRESSING SLOWLY TOWARDS OUR SE OHIO ZONES...WITH MORE PRECIP TO THE SOUTHWEST INTO SE KY AND NORTHEAST TENN AT THIS TIME. WEAK ECHOES SHOWING UP OVERHEAD HERE ON KRLX RADAR BUT VAD PROFILE SHOWING THAT INITIAL PRECIP WILL FIRST HAVE SOME DRY AIR LOWER LEVELS TO OVERCOME...WHICH IT WILL EVENTUALLY DO. STILL ALSO WATCHING FOR ANY BANDING SETTING UP OVER OUR AREA OR TO OUR SW TO HOPEFULLY PINPOINT ANY TARGET AREAS. 10 PM UPDATE...UPDATED SNOW GRIDS BASED ON CURRENT MODEL RUNS. MADE LITTLE CHANGES TO OVERALL TOTALS. STILL LOOKING AT 1 TO 2 ACROSS MUCH OF THE NORTH...WITH 2 TO 4 ACROSS CENTRAL AND NORTHERN WV LOWLANDS...AND 2 TO 5 AS A GENERAL RULE ACROSS THE MOUNTAINS. NEW MODEL RUNS STARTING TO HIT HARDER ON QPF FOR BAND OF SNOWFALL ACROSS SOUTHEAST OHIO THIS EVENING. AT THIS POINT...DID UP SNOWFALL TOTALS...BUT KEPT BELOW ADVISORY CRITERIA AT THIS POINT. WILL ALLOW THE MIDNIGHT SHIFT TO KEEP AN EYE ON AND ADD AN ADVISORY TO THESE AREAS IF NEED BE. PREVIOUS DISCUSSION FOLLOWS... KEPT SOME DZ IN WX GRIDS A FEW MORE HRS THIS AFTN ALONG AND E OF I79 CORRIDOR. THINK THE LOW CRUD STRATUS HOLDS INTO THE OVERNIGHT ACROSS THE LOWLANDS AND PORTIONS OF THE MTNS. MAY SEE SOME BREAKS ACROSS NE KY/SE OH AND W LOWLANDS BEFORE FILLING BACK IN LATE AHEAD OF THE NEXT SYSTEM. TEMPS WILL GRADUALLY FALL TONIGHT WITH POTENTIAL FOR SOME PATCHY BLACK ICE FOR ANY UNTREATED SURFACES THAT HAVE LINGERING MOISTURE. NOW FOR UPCOMING SYSTEM. GFS...NAM AND 00Z RUNS OF HI RESOLUTION WRFS DEPICT A BAND OF ADVISORY LEVEL SNOW FROM NEAR MT STERLING TO HUNTINGTON...NE THRU CHARLESTON...CLARKSBURG AND N MTNS. THE SREF...GEM...AND RUC WOULD HAVE THE HIGHER QPF FURTHER E...CLOSER TO THE BAROCLINIC ZONE. THIS CREATES TWO CAMPS REGARDING SNOW ACCUMS WITH ADVISORY LEVEL SNOW FROM THE LATTER GROUP PRIMARILY ACROSS THE MOUNTAINS. HPC WWD ALSO NOTED THIS SPLIT IN THEIR WINTER QPF GRIDS. WILL TRY TO TAKE A BLEND WITH THIS WHICH WOULD WARRANT ADVISORIES FOR ALL OF WV COUNTIES ALONG WITH SW VA AND PORTIONS OF NE KY. THERE IS ENOUGH AGREEMENT TO LEAVE OUT SE OH AS THIS AREA MAY BE BETWEEN SFC WAVE AND BAND FROM UPPER LEVEL TROF AS WELL AS GREENUP AND CARTER AND NEW 18Z NAM ROLLING HAS SHIFTED E MORE IN LINE WITH SREF/CMC/RUC. NONETHELESS HAVE ISSUED HEADLINES RUNNING FROM 06Z TO 20Z ALTHOUGH THE END TIME MAY BE ABLE TO DROP EARLY. APPEARS HIGHER AMOUNTS WOULD BE ACROSS THE N LOWLANDS AND N MTNS AS THE UPPER TROF APPROACHES TO HELP IN SOME MESOSCALE BANDING VIA SOME SLANTWISE INSTABILITY AND JET DYNAMICS. THIS IS WHERE SOME 2 TO 4 WAS CODED UP FOR C AND N LOWLANDS WITH 3 TO 6 FOR N MOUNTAINS. 1 TO 3 S WV/SW VA WITH LESS THAN AN INCH SE OH TO OH RIVR. BAND WITH THE UPPER TROF LOOKS TO AFFECT N REACHES OF SE OH COUNTIES...IE PERRY/MORGAN. ALSO SE WV/BKW...AND SW VA...THERMAL PROFILES INDICATE POTENTIAL FOR A MIX. UPPER SYS AND SFC WAVE QUICKLY PULLS E BY 18Z WITH SOME PARTIAL CLEARING ACROSS SE OH INTO NE KY. HAVE KEPT TEMPS BELOW FREEZING ALL LOCATIONS TOMORROW WITH ONLY A MODEST REBOUND AFTER THE SNOW MOVES OUT. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST PREVAILING THROUGH THE PERIOD. ZONAL FLOW ALOFT WILL PROVIDE FOR DRY WEATHER WEDNESDAY THROUGH THURSDAY NIGHT. MODELS SUGGEST A SHORTWAVE...EVIDENT IN H5 VORTICITY MAX RIDING IN A LOW AMPLITUDE TROUGH REACHING EXTREME NORTHERN WV BY 06Z THURSDAY. THIS CLIPPER SYSTEM WILL REINFORCE THE COLD AIR BY WEDNESDAY NIGHT. LIMITED MOISTURE WILL PROVIDE FOR PLENTY OF CLOUDS...AND SNOW SHOWERS LIMITED TO UPSLOPE IN THE MOUNTAINS MAINLY IN THE COLD ADVECTION WNW FLOW ONCE THE FRONT PASSES OVERNIGHT WED NT. ARCTIC HIGH PRESSURE BUILDS IN ON THU. HIGHS FOR WEDNESDAY WILL REMAIN AT OR BELOW FREEZING FOR THE MOST PART. MODELS SHOW COLD AIR ADVECTION AT H85 CONTINUING AS FLOW TURNS NORTHWEST REACHING MINUS 18C BY 12Z THURSDAY. THEREFORE...EXPECT LOWS INTO THE TEENS FOR THE MOST PART FOR LOWS WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. THE COLD AIR WILL REMAIN IN PLACE THURSDAY FOR EVEN COLDER TEMPERATURES FOR HIGHS...MAINLY IN THE 20S LOWLANDS...RANGING INTO THE TEENS HIGHEST ELEVATIONS. USED A MIXTURE OF GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD. CLOSER TO THE COLDEST GFS WEDNESDAY AND WEDNESDAY NIGHT. FOR THURSDAY STAYED CLOSER TO THE CONSENSUS MOS. && .LONG TERM /FRIDAY THROUGH MONDAY/... MODELS SHOWING AN INTERESTING SYSTEM FOR SATURDAY INTO SUNDAY...WITH POTENTIAL WINTER WEATHER ON THE ONSET. STILL LOTS OF SPREAD IN THE MODELS HOWEVER...SO WOULD NOT PUT MUCH STOCK IN THE DETAILS AT THIS TIME. USED A BLEND OF THE GEFS MEAN/ECMWF MEAN/GFS AND ECMWF. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... 00Z TUESDAY THROUGH 00Z WEDNESDAY PRIMARILY MVFR STRATUS TONIGHT WITH SOME IFR CIGS/VSBY IN THE MOUNTAINS AMID PATCHY DZ. AN UPPER DISTURBANCE WILL MOVE INTO THE REGION LATE TONIGHT...WITH SNOW DEVELOPING ACROSS THE AREA GENERALLY AROUND THE 07Z-08Z TIME FRAME. BULK OF PRECIPITATION WILL GENERALLY BE ALONG AND SOUTH/EAST OF A LINE FROM CKB TO CRW TO HTS...THOUGH LOCATIONS FURTHER NORTH AND WEST WILL LIKELY SEE SOME SNOW AS WELL. EXPECT WIDESPREAD IFR AND LIFR CONDITIONS IN SNOW. SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST AFTER 15Z TUESDAY...WITH A GRADUAL RETURN TO MVFR CONDITIONS...WITH SOME IMPROVEMENT TO VFR GENERALLY AFTER 18Z ACROSS THE WEST...AND PERHAPS 21Z FOR EASTERN TERMINALS SUCH AS CKB-BKW-EKN. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST. TIMING AND INTENSITY OF SNOW AND VIS FROM SNOWFALL RATES MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 12/10/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 CRW CONSISTENCY H M M M M M H H H H M M HTS CONSISTENCY H M H M M M H H H H H M BKW CONSISTENCY M M M M M H H M M H H M EKN CONSISTENCY L L M M M M M M M L L L PKB CONSISTENCY H H H M M M L L L H H M CKB CONSISTENCY H H M M M M M M L L L H AFTER 06Z WEDNESDAY... IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND SUNDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR WVZ005>011-013>020-024>040-046-047. OH...NONE. KY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR KYZ103-105. VA...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR VAZ003-004. && $$ SYNOPSIS...TRM/RPY/30 NEAR TERM...ARJ SHORT TERM...TRM LONG TERM...RPY AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1249 AM EST TUE DEC 10 2013 .SYNOPSIS... WEAK SYSTEM LATE TONIGHT INTO TUESDAY WITH SOME SNOW. CHILLY DRY HIGH PRESSURE WEDNESDAY. ARCTIC FRONT WEDNESDAY NIGHT. ARCTIC HIGH PRESSURE THURSDAY EXITS FRIDAY. ANOTHER SYSTEM THIS WEEKEND. && .NEAR TERM /THROUGH TODAY/... 1230 AM UPDATE... FORECAST ESSENTIALLY ON TRACK AT THIS POINT. ONE FORECASTED BAND OF SNOW LOCATED OUT TO OUR WEST OVER CENTRAL/SW OHIO STILL PROGRESSING SLOWLY TOWARDS OUR SE OHIO ZONES...WITH MORE PRECIP TO THE SOUTHWEST INTO SE KY AND NORTHEAST TENN AT THIS TIME. WEAK ECHOES SHOWING UP OVERHEAD HERE ON KRLX RADAR BUT VAD PROFILE SHOWING THAT INITIAL PRECIP WILL FIRST HAVE SOME DRY AIR LOWER LEVELS TO OVERCOME...WHICH IT WILL EVENTUALLY DO. STILL ALSO WATCHING FOR ANY BANDING SETTING UP OVER OUR AREA OR TO OUR SW TO HOPEFULLY PINPOINT ANY TARGET AREAS. 10 PM UPDATE...UPDATED SNOW GRIDS BASED ON CURRENT MODEL RUNS. MADE LITTLE CHANGES TO OVERALL TOTALS. STILL LOOKING AT 1 TO 2 ACROSS MUCH OF THE NORTH...WITH 2 TO 4 ACROSS CENTRAL AND NORTHERN WV LOWLANDS...AND 2 TO 5 AS A GENERAL RULE ACROSS THE MOUNTAINS. NEW MODEL RUNS STARTING TO HIT HARDER ON QPF FOR BAND OF SNOWFALL ACROSS SOUTHEAST OHIO THIS EVENING. AT THIS POINT...DID UP SNOWFALL TOTALS...BUT KEPT BELOW ADVISORY CRITERIA AT THIS POINT. WILL ALLOW THE MIDNIGHT SHIFT TO KEEP AN EYE ON AND ADD AN ADVISORY TO THESE AREAS IF NEED BE. PREVIOUS DISCUSSION FOLLOWS... KEPT SOME DZ IN WX GRIDS A FEW MORE HRS THIS AFTN ALONG AND E OF I79 CORRIDOR. THINK THE LOW CRUD STRATUS HOLDS INTO THE OVERNIGHT ACROSS THE LOWLANDS AND PORTIONS OF THE MTNS. MAY SEE SOME BREAKS ACROSS NE KY/SE OH AND W LOWLANDS BEFORE FILLING BACK IN LATE AHEAD OF THE NEXT SYSTEM. TEMPS WILL GRADUALLY FALL TONIGHT WITH POTENTIAL FOR SOME PATCHY BLACK ICE FOR ANY UNTREATED SURFACES THAT HAVE LINGERING MOISTURE. NOW FOR UPCOMING SYSTEM. GFS...NAM AND 00Z RUNS OF HI RESOLUTION WRFS DEPICT A BAND OF ADVISORY LEVEL SNOW FROM NEAR MT STERLING TO HUNTINGTON...NE THRU CHARLESTON...CLARKSBURG AND N MTNS. THE SREF...GEM...AND RUC WOULD HAVE THE HIGHER QPF FURTHER E...CLOSER TO THE BAROCLINIC ZONE. THIS CREATES TWO CAMPS REGARDING SNOW ACCUMS WITH ADVISORY LEVEL SNOW FROM THE LATTER GROUP PRIMARILY ACROSS THE MOUNTAINS. HPC WWD ALSO NOTED THIS SPLIT IN THEIR WINTER QPF GRIDS. WILL TRY TO TAKE A BLEND WITH THIS WHICH WOULD WARRANT ADVISORIES FOR ALL OF WV COUNTIES ALONG WITH SW VA AND PORTIONS OF NE KY. THERE IS ENOUGH AGREEMENT TO LEAVE OUT SE OH AS THIS AREA MAY BE BETWEEN SFC WAVE AND BAND FROM UPPER LEVEL TROF AS WELL AS GREENUP AND CARTER AND NEW 18Z NAM ROLLING HAS SHIFTED E MORE IN LINE WITH SREF/CMC/RUC. NONETHELESS HAVE ISSUED HEADLINES RUNNING FROM 06Z TO 20Z ALTHOUGH THE END TIME MAY BE ABLE TO DROP EARLY. APPEARS HIGHER AMOUNTS WOULD BE ACROSS THE N LOWLANDS AND N MTNS AS THE UPPER TROF APPROACHES TO HELP IN SOME MESOSCALE BANDING VIA SOME SLANTWISE INSTABILITY AND JET DYNAMICS. THIS IS WHERE SOME 2 TO 4 WAS CODED UP FOR C AND N LOWLANDS WITH 3 TO 6 FOR N MOUNTAINS. 1 TO 3 S WV/SW VA WITH LESS THAN AN INCH SE OH TO OH RIVR. BAND WITH THE UPPER TROF LOOKS TO AFFECT N REACHES OF SE OH COUNTIES...IE PERRY/MORGAN. ALSO SE WV/BKW...AND SW VA...THERMAL PROFILES INDICATE POTENTIAL FOR A MIX. UPPER SYS AND SFC WAVE QUICKLY PULLS E BY 18Z WITH SOME PARTIAL CLEARING ACROSS SE OH INTO NE KY. HAVE KEPT TEMPS BELOW FREEZING ALL LOCATIONS TOMORROW WITH ONLY A MODEST REBOUND AFTER THE SNOW MOVES OUT. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... HAVING TRANSITIONED TO ZONAL UPPER LEVEL FLOW FROM SW JUST PRIOR TO THE START OF THIS PERIOD...THE FLOW TRANSITIONS FARTHER...TO WNW TO NW...AS L/W TROUGHING MOVES FROM THE CENTER OF THE CONTINENT TO THE EASTERN HALF. FLURRIES IN THE COLD ADVECTION UPSLOPE WNW LOW LEVEL FLOW RIGHT AT THE START OPF THE PERIOD...WIND DOWN OVERNIGHT...AS HIGH PRESSURE BUILDS INTO THE S. A CLIPPER SYSTEM / ARCTIC FRONT MOVES THROUGH LATE WED NT...REINFORCING THE COLD AIR. SNOW SHOWERS WITH THIS MOISTURE STARVED SYSTEM WILL BE LIMITED TO UPSLOPE IN THE MOUNTAINS MAINLY IN THE COLD ADVECTION WNW FLOW ONCE THE FRONT PASSES OVERNIGHT WED NT. ARCTIC HIGH PRESSURE BUILDS IN ON THU. TEMPERATURES TEN TO FIFTEEN DEGREES BELOW NORMAL THIS PERIOD. LOWS TUE NT LOOKED GOOD WITH MINOR CHANGES ONLY. BLENDED IN BIAS CORRECTED ADJMET FOR HIGHS WED...A LITTLE LOWER IN THE N. BLENDED IN BIAS CORRECTED CONSENSUS MOS FOR LOWS WED NT...A LITTLE HIGHER WITH CLIPPER COMING THROUGH EXCEPT LITTLE OR NO CHANGE NW IN THE WAKE OF THE CLIPPER. BLENDED IN ADJMEX AND BIAS CORRECTED ECMWFHIRES FOR LOWER HIGHS IN THE ARCTIC AIR ON THU. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... MODELS SHOWING AN INTERESTING SYSTEM FOR SATURDAY INTO SUNDAY...WITH POTENTIAL WINTER WEATHER ON THE ONSET. STILL LOTS OF SPREAD IN THE MODELS HOWEVER...SO WOULD NOT PUT MUCH STOCK IN THE DETAILS AT THIS TIME. USED A BLEND OF THE GEFS MEAN/ECMWF MEAN/GFS AND ECMWF. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... 00Z TUESDAY THROUGH 00Z WEDNESDAY PRIMARILY MVFR STRATUS TONIGHT WITH SOME IFR CIGS/VSBY IN THE MOUNTAINS AMID PATCHY DZ. AN UPPER DISTURBANCE WILL MOVE INTO THE REGION LATE TONIGHT...WITH SNOW DEVELOPING ACROSS THE AREA GENERALLY AROUND THE 07Z-08Z TIME FRAME. BULK OF PRECIPITATION WILL GENERALLY BE ALONG AND SOUTH/EAST OF A LINE FROM CKB TO CRW TO HTS...THOUGH LOCATIONS FURTHER NORTH AND WEST WILL LIKELY SEE SOME SNOW AS WELL. EXPECT WIDESPREAD IFR AND LIFR CONDITIONS IN SNOW. SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST AFTER 15Z TUESDAY...WITH A GRADUAL RETURN TO MVFR CONDITIONS...WITH SOME IMPROVEMENT TO VFR GENERALLY AFTER 18Z ACROSS THE WEST...AND PERHAPS 21Z FOR EASTERN TERMINALS SUCH AS CKB-BKW-EKN. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST. TIMING AND INTENSITY OF SNOW AND VIS FROM SNOWFALL RATES MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE TUE 12/10/13 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12 CRW CONSISTENCY H H H M M M M M H H H H HTS CONSISTENCY H H H M H M M M H H H H BKW CONSISTENCY M M M M M H H M M M M H EKN CONSISTENCY L L L L M M M M M M M L PKB CONSISTENCY H H H H H M M M L L L H CKB CONSISTENCY H H H H M M M M M M L L AFTER 06Z WEDNESDAY... IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND SUNDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR WVZ005>011-013>020-024>040-046-047. OH...NONE. KY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR KYZ103-105. VA...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR VAZ003-004. && $$ SYNOPSIS...TRM/RPY/30 NEAR TERM...50/SL/30 SHORT TERM...TRM LONG TERM...RPY AVIATION...50
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1150 PM EST MON DEC 9 2013 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST TONIGHT. A FAST MOVING LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE NORTHERN GREAT LAKES REGION TUESDAY WITH A REINFORCING ARCTIC COLD FRONT. HIGH PRESSURE WILL BUILD EAST INTO THE OHIO VALLEY ON THURSDAY AND TO THE EAST COAST ON FRIDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... TWO AREAS OF CONCERN. ONE IS THE POTENTIAL FOR SOME LAKE EFFECT SNOW FOR THE SNOW BELT AREA LATE TONIGHT. THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C BY DAYBREAK TUESDAY. ONE TO LOCALLY TWO INCHES OF SNOW MAY ACCUMULATE. SOME RIDGING WILL HELP KEEP THE SNOWFALL AMOUNTS DOWN. AN IMPULSE IN THE SOUTHWEST FLOW ALOFT WILL CAUSE SOME SNOW IN THE SOUTHERN PORTION OF THE FORECAST AREA AFTER MIDNIGHT...THIS IS IN THE RIGHT REAR QUAD OF THE JET. BASED ON THE RUC MODEL INCREASED THE POPS A LITTLE. THE SNOWFALL AMOUNTS COULD BE AROUND AN INCH. MADE MINOR ADJUSTMENTS TO THE LOWS BASED ON SOME CLOUDS AND WIND. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/... SOME SNOW SHOWERS LINGERS IN THE SNOW BELT AS THE WINDS WILL BECOME SOUTHWEST AND SHIFT THE BANDS INTO THE LAKE. THE SNOW/SNOW SHOWERS OVER THE SE PORTION OF THE FORECAST AREA WILL BE QUICKLY MOVING OUT. ANOTHER FRONT WILL BE MOVING THROUGH THE REGION ON TUESDAY AND THE WINDS ALOFT NEAR THE FRONTAL BOUNDARY WILL BE NEAR 40 KNOTS. ADDED GUSTS UP TO 40 MPH IN THE AFTERNOON. SOME BREAKS IN THE CLOUDS WILL HELP BRING DOWN SOME OF THE WIND. ALSO DEBATED ABOUT ISSUING A LAKE EFFECT WATCH FOR THE SNOW BELT FOR LATE TUESDAY NIGHT INTO THURSDAY. WITH THE 18Z DATA STILL SOME QUESTIONS ABOUT THE WIND DIRECTION AND THE AMOUNT OF MOISTURE. THE GFS IS THE MOST PESSIMISTIC. THE CANADIAN MODEL IS VERY DRY. WITH THAT WILL LET THE MID NIGHT SHIFT TAKE ANOTHER LOOK BEFORE ISSUING OR NOT ISSUING THE LAKE EFFECT WATCH. PREVIOUS DISCUSSION... THE FIRST HALF OF TUESDAY WILL GENERALLY BE DRY AND COOL UNDER THE INFLUENCE OF HIGH PRESSURE. BY TUESDAY EVENING THE NEXT TROUGH ARRIVES AND LAKE EFFECT SNOW WILL SET UP ACROSS NW PA/NE OH. WILL HOLD OFF ON A LAKE EFFECT SNOW WATCH FOR THIS PACKAGE...WITH THE HEAVIEST SNOW NOT FALLING UNTIL OUTSIDE THE THIRD PERIOD. LAKE EFFECT WILL WIND DOWN BY THURSDAY AFTERNOON. MOST AREAS OUTSIDE OF THE SNOWBELT WILL BE DRY. WEDNESDAY NIGHT LOW TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BEHIND AN ARCTIC COLD FRONT. && .LONG TERM /FRIDAY THROUGH MONDAY/... THE MODELS ARE A LITTLE MORE IN AGREEMENT THE SECOND HALF OF THE WEEK WITH HIGH PRESSURE SLIDING EAST AND THE FLOW BACKING TO SOUTHWEST BY FRIDAY. THIS WILL PUT AN END TO THE LAKE EFFECT THREAT. TEMPERATURES SHOULD BOTTOM OUT ON THURSDAY AS SOME OF THE ARCTIC AIR FILTERS ACROSS THE AREA. THE TREND UPWARD WILL BE RELATIVELY SLOW AS MOST OF THE COUNTRY WILL BE TRYING TO MODIFY FROM ARCTIC AIR AND OF COURSE THE SUN ANGLE IS AT A MINIMUM THIS TIME OF YEAR. FORECAST HIGHS MOSTLY IN THE TEENS THURSDAY AND 20S ON FRIDAY. STILL NO CONFIDENCE ON THE SCENARIO FOR SATURDAY. THE MODELS SHOW A DECENT SHORT WAVE AND CORRESPONDING SURFACE LOW TRACKING FROM THE SOUTH CENTRAL STATES AND ENDING UP ALONG THE MID ATLANTIC COAST. THESE SYSTEMS OFTEN REDEVELOP FROM THE OHIO VALLEY TO THE EAST COAST AND WE END UP IN THE TRANSITION ZONE SO NOT A LOT OF CONFIDENCE ON THE STRENGTH AND TRACK OF THE SURFACE LOW YET. THE FORECAST WILL GO FOR TEMPERATURES NEAR FREEZING ON SATURDAY AND A CHANCE OF SNOW. WE MAY END UP NEEDING HIGHER POPS AND A MIX OF PRECIPITATION BUT WILL WAIT TO SEE THE MODEL TRENDS THIS WEEK. COLDER AGAIN BY SUNDAY INTO MONDAY AS THE PATTERN REMAINS COLD. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... A WEAK MID LEVEL SYSTEM WILL SPREAD SOME LIGHT SNOW OR FLURRIES ENE ACROSS THE SOUTHERN HALF OF THE AREA FROM 07Z THRU ABOUT 13Z. CAK MAY SEE 3 OR 4 HOURS OF IFR VSBYS WITH THE LIGHT SNOW...MFD AND YNG WILL HAVE A LESSOR THREAT WHILE CLE SHOULD ONLY SEE A FEW FLURRIES AT MOST. ERI WILL KEEP AN ONGOING THREAT FOR SCT LIGHT SHSN AS LAKE EFFECT CONDITIONS SET UP WITH MEAN LOW LEVEL WINDS HAVING JUST ENOUGH ONSHORE COMPONENT FOR THE SNOW BANDS TO SPREAD INTO THE ERI AREA. AS USUAL WITH LAKE EFFECT SHSN...EXPECT TO SEE HIGHLY VARIABLE CONDITIONS AS THE ON AND OFF SHSN OCCUR. AN AREA OF DRYER LOW LEVEL DRY AIR WORKS EAST ACROSS THE TAF SITES AND LOOKS TO BE OVER TOL...FDY THRU MID MORNING AND OVER THE EASTERN SITES EARLY TO MID AFTERNOON. ANY LEFTOVER MVFR AT MFD...CAK AND YNG SHOULD LIFT TO VFR AS THE DRYER AIR MOVES IN. HOWEVER...AT ERI CONDITIONS LOOK GOOD ENOUGH FOR LAKE EFFECT SHSN TO CONTINUE TO PESTER THE AREA THRU THE DAY TUE AND TUE EVE OR AT LEAST BE ON THE NORTH SIDE OF THE AIRSPACE. WSW WINDS MAY GUST AROUND 20 KNOTS NEAR THE LAKESHORE TONIGHT THEN INCREASE AGAIN LATER TUE MORNING INTO MID AFTERNOON TO BE GUSTING 25 TO 30 KNOTS WITH THE HIGHER GUSTS AT TOL AND FDY AND ALONG THE LAKESHORE. OUTLOOK...NON VFR CONDITIONS WILL LINGER AT TIMES THROUGH THURSDAY...MAINLY OVER NE OH/NW PA. && .MARINE... ALLOWING GALE WARNING TO EXPIRE AS PLANNED AT 7 PM. IF WIND FORECAST NEEDS TO BE INCREASED A LITTLE MORE WITH NEW 00Z DATA ON THE MID SHIFT THEN WILL LIKELY NEED ANOTHER GALE FOR THE EAST HALF OF THE LAKE FOR LATER TUE INTO TUE NIGHT. OTHERWISE...SCA CONDITIONS WILL TEND TO PREVAIL INTO THU WEST PART AND INTO THU NIGHT EAST PART. THERE WILL BE A BRIEF LULL IN WINDS AND WAVES FOR THE WEST PART OF THE LAKE LATER TONIGHT INTO THE BEGINNING OF TUE BUT CONSENSUS IS TO JUST LEAVE THE SCA GOING SINCE CONDITIONS RAMP BACK UP QUICKLY LATER TUE MORNING. THE GRADIENT WILL REMAIN RATHER STRONG WEDNESDAY INTO THURSDAY...THEN RELAX AS THE SURFACE HIGH MOVES EAST ACROSS THE OHIO VALLEY. A STORM SYSTEM WILL AFFECT THE LOWER GREAT LAKES ON THE WEEKEND BUT NOT MUCH CONFIDENCE ON THE STRENGTH AND TRACK OF THE SYSTEM YET. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THURSDAY FOR LEZ145>149. SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR LEZ142>144. && $$ SYNOPSIS...MAYERS NEAR TERM...KIELTYKA SHORT TERM...KIELTYKA/MAYERS LONG TERM...KOSARIK AVIATION...ADAMS MARINE...ADAMS/KOSARIK
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
331 AM EST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT)...RAIN MOVING NE ACROSS THE REGION AS EXPECTED THIS MORNING. HOWEVER...TEMPS REMAIN IN THE MID 30S TO MID 40S...EXCEPT FOR PERHAPS LOWER 30S ACROSS OUR NRN MOST PLATEAU COUNTIES. RUC MODEL SHOWS 850 MB TEMPS FALLING BELOW 0 DEGS CELSIUS ACROSS THE WINTER WEATHER ADVISORY AREAS BY 09Z TO 12Z...SO STILL SOME POTENTIAL FOR A BRIEF PERIOD OF ICING. ICE ACCUMS WERE LOWERED IN FORECAST GRIDS DUE TO SURFACE TEMPS STILL ABOVE FREEZING FOR A BIT LONGER. MODEL SOUNDINGS SHOW MAINLY LIGHT SNOW AS WEATHER TYPE AFTER 12Z AS THE AIRMASS COOLS QUICKLY...SO DOWNPLAYED FREEZING RAIN AND WENT WITH MAIN TYPE AS SNOW. ALL PCPN ENDS BY 16Z EVEN IN THE FAR NE AREAS. NO CHANGES MADE TO THE ADVISORY AREA OR ENDING TIME. OTHERWISE...STRONG COLD AIR ADVECTION FAVORS GOING WITH OR BELOW THE COOLER MOS MAX TEMPS FOR TODAY. CLEAR AND CHILLY TONIGHT AS SURFACE RIDGE OF HIGH PRESSURE SETTLES OVER THE REGION. .LONG TERM.../WEDNESDAY THROUGH MONDAY/... IN WAKE OF THE SHORTWAVE TROUGH THAT WILL MOVE THROUGH THE REGION ON TUESDAY...ZONAL FLOW ALOFT WILL PREVAIL FOR THE REMAINDER OF THE WORK WEEK AS A SURFACE HIGH PRESSURE BUILDS IN. THIS WILL RESULT IN MOSTLY SUNNY AND DRY CONDITIONS...WITH HIGHS IN THE 40S TO LOWER 50S. BY FRIDAY HOWEVER...CLOUDS WILL GRADUALLY BE ON THE INCREASE AS ANOTHER UPPER-LEVEL TROUGH SWINGS THROUGH THE SOUTHERN PLAINS AND INTO THE LOWER MISSISSIPPI VALLEY. SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL INCREASE GULF MOISTURE ACROSS THE AREA AND ALLOW FOR PRECIPITATION TO OVERSPREAD THE REGION FRIDAY NIGHT INTO SATURDAY. THEN AS THE BASE OF THE TROUGH SWINGS THROUGH THE TENNESSEE VALLEY SATURDAY NIGHT INTO SUNDAY...COOLER AIR WILL FILTER INTO THE AREA AND RESULT IN THE POTENTIAL FOR SOME WINTERY PRECIPITATION /PARTICULARLY ALONG THE HIGHER TERRAIN OF THE CUMBERLAND PLATEAU... SOUTHWEST VIRGINIA AND THE SMOKY MOUNTAINS OF EAST TENNESSEE/. ATTM THERE IS A GREAT DEAL OF UNCERTAINTY WITH RESPECT TO THE POTENTIAL IMPACT OF THE WINTER WEATHER GIVEN UNCERTAINTIES IN THE TIMING AND TRACK OF THIS SYSTEM. THUS...HAVE BEEN CAUTIOUS IN ADJUSTING THE FORECAST TOO MUCH ATTM...BUT HAVE INCREASED POPS TO SHOW A GREATER CONFIDENCE IN PRECIPITATION OCCURRING DURING THIS TIME PERIOD. THE PRECIPITATION WILL WANE ON SUNDAY...RESULTING IN DRY CONDITIONS TO BEGIN THE NEW WORK WEEK ON MONDAY. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 44 25 50 26 43 / 20 10 0 0 0 KNOXVILLE MCGHEE TYSON AIRPORT, TN 42 23 46 25 38 / 50 10 0 0 0 OAK RIDGE, TN 41 23 45 24 39 / 40 10 0 0 0 TRI CITIES AIRPORT, TN 40 18 41 21 35 / 60 10 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...WINTER WEATHER ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR THE FOLLOWING ZONES: ANDERSON...BLEDSOE...CAMPBELL... CLAIBORNE...GRAINGER...HANCOCK...HAWKINS...JOHNSON... MARION...MORGAN...SCOTT TN...SEQUATCHIE...SULLIVAN...UNION. VA...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR THE FOLLOWING ZONES: LEE...RUSSELL...SCOTT...WASHINGTON...WISE. && $$ TG/AMP
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1132 PM CST MON DEC 9 2013 .AVIATION 06Z DISCUSSION... WINTRY PRECIPITATION TO OVERSPREAD THE MID STATE THROUGH 09Z. THE PRECIP SHOULD END IN SOUTHWEST AREAS OF MIDDLE TN AROUND 10Z AND THEN NORTHEAST AREAS AROUND 14Z. CONDITIONS WILL IMPROVE MARKEDLY BY 18Z WITH CLEARING SKIES TOWARD 00Z. THE BULK OF THE PRECIP TYPE WILL BE -SN AT BNA AND CKV. CSV...HOWEVER...WILL CONTEND WITH -PL AND FZRA WITH A TRANSITION TO SOME SNOW AROUND 09Z. && .PREV DISCUSSION... /ISSUED 1044 PM CST MON DEC 9 2013/ UPDATE RADAR INDICATING THAT THE PRECIPITATION APPROACHING BNA IS ALL SNOW ABOVE 1200 FT. MELTING BELOW THAT LEVEL LOOKS UNLIKELY AND THUS...SNOW SHOULD BEGIN SHORTLY ACROSS NORTHERN AREAS. MOSTLY SLEET IS FALLING CENTRAL...AND FREEZING RAIN SOUTH. LAWRENCE AND MARSHALL COUNTIES ARE BOTH REPORTING ICE COATING MOST ELEVATED SURFACES. CAA TO CONTINUE. THEREFORE...CURRENT FCST IS ON TRACK IN TERMS OF TRANSITIONING. WE HAVE RECENTLY UPPED OUR SNOW AMOUNTS...PARTICULARLY NC AND NE AREAS WHERE 1 TO 2 INCHED OF SNOW IS NOW POSSIBLE. LESS THAN 1 INCH ACROSS THE NON ADVISORY NW AREA. FOR SOUTHERN AREAS...UP TO ONE QUARTER INCH OF ICE WILL BE POSSIBLE. ALL PRECIP SHOULD END SHORTLY AFTER SUNRISE ACROSS THE PLATEAU. UPDATES HAVE BEEN SENT. STILL CONCERNED WITH LATEST RUC WHICH PAINTS A LITTLE EXTRA QPF FROM NASHVILLE NE THROUGH THE EASTERN HIGHLAND RIM AREA THROUGH 09Z. WILL AWAIT THE WHITES OF ITS EYES BEFORE UPPING SNOW AMTS AGAIN. NOT SOLD ON RUC. PREV DISCUSSION... /ISSUED 712 PM CST MON DEC 9 2013/ UPDATE... SFC FREEZING LINE NOW EXTENDS GENERALLY ALONG I-65...WITH SUB FREEZING TEMPS TO THE WEST EXCEPT 32-34 SOUTHWEST. TEMPS ACROSS THE PLATEAU ARE IN THE LOW TO MID 30S. RADAR TRENDS FROM RADARS TO OUR SOUTHWEST SHOW A DEFINITIVE INCREASE IN PRECIP COVERAGE ACROSS MS AND EASTERN AR. MODELS ARE IN AGREEMENT WITH SPREADING THIS MOISTURE NORTHEASTWARD RATHER RAPIDLY. BY 06Z...MUCH OF THE SOUTHEASTERN TWO THIRDS OF THE MID STATE WILL BE RECEIVING PRECIPITATION. IT STILL LOOKS AS THOUGH THE SOUTHERN AND PLATEAU AREAS COULD RECEIVE TOTAL LIQ EQUIVALENT AMOUNTS OF BETWEEN ONE QUARTER AND ONE HALF INCH. IF THE BULK OF THIS FALLS WITH SUB FREEZING TEMPS IN PLACE...WE WILL NEED TO CONSIDER UPGRADING TO A WINTER STORM WARNING FOR THAT EASTERN AND SOUTHERN AREA. FOR NOW THOUGH...WILL KEEP THE ADVISORY GOING BUT WILL INCREASE ICE AMOUNTS ACROSS THE SOUTH AND PLATEAU TO TWO TENTHS OF AN INCH. WILL ALSO ADJUST GRAPHICS SO THAT SNOW AMOUNTS SUPPORT THE ADVISORY CRITERIA ON THE NORTHWESTERN EDGE OF THE ADVISORY. OTW...LATEST SOUNDING IS RATHER DRY ABOVE 800 MB AND LOOKS LIKE A SNOW SOUNDING CONSIDERING THE UPCOMING WET BULB COOLING THAT WILL TAKE PLACE. FURTHER SOUTH...FREEZING RAIN WILL BE THE BIGGER IMPACT ACROSS THE SOUTH AND PLATEAU. AGAIN...THIS AREA WILL NEED TO BE WATCHED. UPDATES OUT SHORTLY. PREV DISCUSSION... /ISSUED 552 PM CST MON DEC 9 2013/ AVIATION 00Z DISCUSSION... ANOTHER STORM SYSTEM WILL MOVE NORTHEASTWARD FROM THE NORTHERN GULF AND SPREAD WINTRY PRECIPITATION BACK ACROSS THE MID STATE OVERNIGHT. SOME SIGNIFICANT ICING WILL BE POSSIBLE NEAR CSV AFT 06Z. A GRADUAL SHIFT TO ALL SNOW CAN BE EXPECTED BETWEEN 9 AND 12Z. OVERALL PRECIP AMOUNTS WILL BE GREATEST ACROSS CSV WITH MUCH LIGHTER AMOUNTS EXPECTED AT CKV. THE IFR CIGS WILL CONTINUE THROUGH 18Z. AFT 18Z...PARTIAL CLEARING IS EXPECTED. PREV DISCUSSION... /ISSUED 420 PM CST MON DEC 9 2013/ SHORT TERM... ANOTHER DAY ANOTHER ROUND OF WINTRY PRECIPITATION IS EXPECTED YET AGAIN TONIGHT ACROSS THE MID STATE AS PRECIPITATION DEVELOPING TO THE SOUTHWEST SPREADS NORTHEASTWARD ATOP THE COLD ARCTIC AIRMASS ENTRENCHED OVER THE REGION. SHOWERS AND THUNDERSTORMS ARE NOW DEVELOPING ACROSS TEXAS/LOUISIANA/MISSISSIPPI...AND THIS ACTIVITY WILL SPREAD NORTHEASTWARD VERY RAPIDLY AND REACH THE MID STATE THIS EVENING BEFORE SPREADING QUICKLY ACROSS THE AREA TONIGHT AND EXITING BY TUESDAY MORNING. MODELS ARE FINALLY IN DECENT AGREEMENT ON EVOLUTION OF SYSTEM TONIGHT...AND AFTER AN EXTENSIVE ANALYSIS OF ALL 12Z MODEL DATA A WINTER WEATHER ADVISORY WAS ISSUED FOR THE SOUTHEAST TWO-THIRDS OF THE MID STATE...ROUGHLY SOUTHEAST OF A LINE FROM LINDEN TO GALLATIN. AN EXTENSIVE LOOK AT 12Z GFS/NAM FORECAST SOUNDINGS INDICATE AREAS ALONG AND SOUTH OF A LINE FROM WAYNESBORO TO CROSSVILLE WILL INITIALLY SEE PRECIP FALL AS RAIN WITH TEMPERATURES IN THE MID 30S...BUT AS TEMPERATURES FALL BELOW FREEZING LATER THIS EVENING AND TONIGHT A TRANSITION TO ALL FREEZING RAIN IS ANTICIPATED. QPF AMOUNTS SUGGEST AROUND ONE TENTH OF ICE ACCUMULATION IS MOST LIKELY IN THIS AREA...WITH MAIN IMPACTS BEING POTENTIALLY ICY BRIDGES AND OVERPASSES. PRECIP MAY CHANGEOVER TO ALL SNOW TOWARDS THE END OF THE EVENT BUT LITTLE OR NO SNOW ACCUMULATION IS LIKELY IN THIS AREA. NORTH OF THE LINE FROM WAYNESBORO TO CROSSVILLE IN THE ADVISORY AREA...A MIX OF PRECIP TYPES IS EXPECTED INITIALLY WITH SOUNDINGS DEPICTING A DEEP SURFACE COLD LAYER WITH ONLY A RELATIVELY WEAK WARM NOSE ALOFT...SUGGESTING PREDOMINATELY SLEET OR SNOW FURTHER NORTH AND FZRA FURTHER SOUTH. STRONG LIFT AND SATURATING/COOLING OF THE ENTIRE COLUMN SHOULD CHANGE ANY SLEET/FZRA OVER TO SNOW NEAR/AFTER MIDNIGHT IN THIS PART OF THE ADVISORY AREA. QPF AMOUNTS INDICATE A DUSTING TO 1 INCH OF SNOW WOULD BE MOST COMMON WITH HIGHEST AMOUNTS EAST OF I-65 AND NORTH OF I-40...WITH TRAVEL SEEING THE MOST IMPACTS DUE TO POTENTIALLY SNOWY BRIDGES AND OVERPASSES. LONGER DURATION OF PRECIP AND COOLER TEMP PROFILES SUGGEST NORTHERN CUMBERLAND PLATEAU COULD END UP WITH HIGHER SNOW ACCUMS...AND THIS WILL HAVE TO BE CLOSELY MONITORED AS THE EVENT UNFOLDS. PRECIPITATION WILL BE ENCOUNTERING A VERY DRY AIRMASS ALOFT TO THE NORTHWEST OF THE MID STATE...AND A SHARP NORTHWEST EDGE TO THE PRECIP SHIELD IS ANTICIPATED LIKELY SOMEWHERE ALONG A LINE FROM LINDEN TO LAFAYETTE...WITH LITTLE OR NO PRECIP AT ALL ANTICIPATED IN NORTHWEST ZONES. THIS BACK EDGE TO THE PRECIP GIVES THE FORECAST CONSIDERABLE BUST POTENTIAL FOR THE NORTHWEST COUNTIES WITHIN THE ADVISORY AREA. UNFORTUNATELY...THIS BACK EDGE TO THE PRECIP WILL ALSO LIKELY BISECT THE NASHVILLE METRO...SO NORTHWEST PORTIONS OF THE METRO AREA MAY SEE LITTLE OR NO PRECIPITATION WHILE SOUTHEAST SECTIONS ARE MORE IMPACTED. EVEN MORE UNCERTAIN ARE CONVECTIVE ELEMENTS WITH THE PRECIP AS SOUNDINGS DEPICT SOME ELEVATED INSTABILITY...SO IF STRONGER CONVECTION CAN FORM FZRA/ICE/SNOW AMOUNTS COULD BE HIGHER IN SOME LOCATIONS. LONG TERM... MAIN FORECAST FOCUS WAS ON WINTER WEATHER TONIGHT...SO FORECAST FOR REST OF THE WEEK RELIED HEAVILY ON THE 12Z GFS. APPEARS CLOUDS WILL FINALLY CLEAR ACROSS THE CWA BY TUESDAY AFTERNOON AS STRONG NORTHWEST FLOW DEVELOPS IN THE LOW LEVELS...BUT THIS WILL RESULT IN SEVERAL COLD DAYS FOR THE MIDDLE OF THE WEEK WITH LOWS IN THE TEENS NORTHWEST TO 20 ELSEWHERE AND HIGHS ONLY IN THE 30S AND 40S. WARMING TREND ANTICIPATED BY FRIDAY AS SURFACE RIDGE MOVES EAST AND SOUTHERLY FLOW DEVELOPS. COULD SEE A BIT OF A RAIN/SNOW MIX ON THE PLATEAU EARLY FRIDAY NIGHT...BUT EVENTUALLY ALL RAIN IS EXPECTED EVERYWHERE AS TEMPS WARM CONSIDERABLY INTO SATURDAY. STRONG CAA IN THE WAKE OF THE UPCOMING WEEKEND SYSTEM WILL BRING MUCH COLDER TEMPERATURES AND OUR NEXT CHANCE FOR LIGHT SNOW SATURDAY NIGHT...ALTHOUGH MAIN DEFORMATION BAND LOOKS TO STAY WELL NORTH OF THE MID STATE. && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR TNZ008>011- 027>034-056>066-075-077>080-093>095. && $$ 21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1044 PM CST MON DEC 9 2013 .UPDATE RADAR INDICATING THAT THE PRECIPITATION APPROACHING BNA IS ALL SNOW ABOVE 1200 FT. MELTING BELOW THAT LEVEL LOOKS UNLIKELY AND THUS...SNOW SHOULD BEGIN SHORTLY ACROSS NORTHERN AREAS. MOSTLY SLEET IS FALLING CENTRAL...AND FREEZING RAIN SOUTH. LAWRENCE AND MARSHALL COUNTIES ARE BOTH REPORTING ICE COATING MOST ELEVATED SURFACES. CAA TO CONTINUE. THEREFORE...CURRENT FCST IS ON TRACK IN TERMS OF TRANSITIONING. WE HAVE RECENTLY UPPED OUR SNOW AMOUNTS...PARTICULARLY NC AND NE AREAS WHERE 1 TO 2 INCHED OF SNOW IS NOW POSSIBLE. LESS THAN 1 INCH ACROSS THE NON ADVISORY NW AREA. FOR SOUTHERN AREAS...UP TO ONE QUARTER INCH OF ICE WILL BE POSSIBLE. ALL PRECIP SHOULD END SHORTLY AFTER SUNRISE ACROSS THE PLATEAU. UPDATES HAVE BEEN SENT. STILL CONCERNED WITH LATEST RUC WHICH PAINTS A LITTLE EXTRA QPF FROM NASHVILLE NE THROUGH THE EASTERN HIGHLAND RIM AREA THROUGH 09Z. WILL AWAIT THE WHITES OF ITS EYES BEFORE UPPING SNOW AMTS AGAIN. NOT SOLD ON RUC. PREV DISCUSSION... /ISSUED 712 PM CST MON DEC 9 2013/ UPDATE... SFC FREEZING LINE NOW EXTENDS GENERALLY ALONG I-65...WITH SUB FREEZING TEMPS TO THE WEST EXCEPT 32-34 SOUTHWEST. TEMPS ACROSS THE PLATEAU ARE IN THE LOW TO MID 30S. RADAR TRENDS FROM RADARS TO OUR SOUTHWEST SHOW A DEFINITIVE INCREASE IN PRECIP COVERAGE ACROSS MS AND EASTERN AR. MODELS ARE IN AGREEMENT WITH SPREADING THIS MOISTURE NORTHEASTWARD RATHER RAPIDLY. BY 06Z...MUCH OF THE SOUTHEASTERN TWO THIRDS OF THE MID STATE WILL BE RECEIVING PRECIPITATION. IT STILL LOOKS AS THOUGH THE SOUTHERN AND PLATEAU AREAS COULD RECEIVE TOTAL LIQ EQUIVALENT AMOUNTS OF BETWEEN ONE QUARTER AND ONE HALF INCH. IF THE BULK OF THIS FALLS WITH SUB FREEZING TEMPS IN PLACE...WE WILL NEED TO CONSIDER UPGRADING TO A WINTER STORM WARNING FOR THAT EASTERN AND SOUTHERN AREA. FOR NOW THOUGH...WILL KEEP THE ADVISORY GOING BUT WILL INCREASE ICE AMOUNTS ACROSS THE SOUTH AND PLATEAU TO TWO TENTHS OF AN INCH. WILL ALSO ADJUST GRAPHICS SO THAT SNOW AMOUNTS SUPPORT THE ADVISORY CRITERIA ON THE NORTHWESTERN EDGE OF THE ADVISORY. OTW...LATEST SOUNDING IS RATHER DRY ABOVE 800 MB AND LOOKS LIKE A SNOW SOUNDING CONSIDERING THE UPCOMING WET BULB COOLING THAT WILL TAKE PLACE. FURTHER SOUTH...FREEZING RAIN WILL BE THE BIGGER IMPACT ACROSS THE SOUTH AND PLATEAU. AGAIN...THIS AREA WILL NEED TO BE WATCHED. UPDATES OUT SHORTLY. PREV DISCUSSION... /ISSUED 552 PM CST MON DEC 9 2013/ AVIATION 00Z DISCUSSION... ANOTHER STORM SYSTEM WILL MOVE NORTHEASTWARD FROM THE NORTHERN GULF AND SPREAD WINTRY PRECIPITATION BACK ACROSS THE MID STATE OVERNIGHT. SOME SIGNIFICANT ICING WILL BE POSSIBLE NEAR CSV AFT 06Z. A GRADUAL SHIFT TO ALL SNOW CAN BE EXPECTED BETWEEN 9 AND 12Z. OVERALL PRECIP AMOUNTS WILL BE GREATEST ACROSS CSV WITH MUCH LIGHTER AMOUNTS EXPECTED AT CKV. THE IFR CIGS WILL CONTINUE THROUGH 18Z. AFT 18Z...PARTIAL CLEARING IS EXPECTED. PREV DISCUSSION... /ISSUED 420 PM CST MON DEC 9 2013/ SHORT TERM... ANOTHER DAY ANOTHER ROUND OF WINTRY PRECIPITATION IS EXPECTED YET AGAIN TONIGHT ACROSS THE MID STATE AS PRECIPITATION DEVELOPING TO THE SOUTHWEST SPREADS NORTHEASTWARD ATOP THE COLD ARCTIC AIRMASS ENTRENCHED OVER THE REGION. SHOWERS AND THUNDERSTORMS ARE NOW DEVELOPING ACROSS TEXAS/LOUISIANA/MISSISSIPPI...AND THIS ACTIVITY WILL SPREAD NORTHEASTWARD VERY RAPIDLY AND REACH THE MID STATE THIS EVENING BEFORE SPREADING QUICKLY ACROSS THE AREA TONIGHT AND EXITING BY TUESDAY MORNING. MODELS ARE FINALLY IN DECENT AGREEMENT ON EVOLUTION OF SYSTEM TONIGHT...AND AFTER AN EXTENSIVE ANALYSIS OF ALL 12Z MODEL DATA A WINTER WEATHER ADVISORY WAS ISSUED FOR THE SOUTHEAST TWO-THIRDS OF THE MID STATE...ROUGHLY SOUTHEAST OF A LINE FROM LINDEN TO GALLATIN. AN EXTENSIVE LOOK AT 12Z GFS/NAM FORECAST SOUNDINGS INDICATE AREAS ALONG AND SOUTH OF A LINE FROM WAYNESBORO TO CROSSVILLE WILL INITIALLY SEE PRECIP FALL AS RAIN WITH TEMPERATURES IN THE MID 30S...BUT AS TEMPERATURES FALL BELOW FREEZING LATER THIS EVENING AND TONIGHT A TRANSITION TO ALL FREEZING RAIN IS ANTICIPATED. QPF AMOUNTS SUGGEST AROUND ONE TENTH OF ICE ACCUMULATION IS MOST LIKELY IN THIS AREA...WITH MAIN IMPACTS BEING POTENTIALLY ICY BRIDGES AND OVERPASSES. PRECIP MAY CHANGEOVER TO ALL SNOW TOWARDS THE END OF THE EVENT BUT LITTLE OR NO SNOW ACCUMULATION IS LIKELY IN THIS AREA. NORTH OF THE LINE FROM WAYNESBORO TO CROSSVILLE IN THE ADVISORY AREA...A MIX OF PRECIP TYPES IS EXPECTED INITIALLY WITH SOUNDINGS DEPICTING A DEEP SURFACE COLD LAYER WITH ONLY A RELATIVELY WEAK WARM NOSE ALOFT...SUGGESTING PREDOMINATELY SLEET OR SNOW FURTHER NORTH AND FZRA FURTHER SOUTH. STRONG LIFT AND SATURATING/COOLING OF THE ENTIRE COLUMN SHOULD CHANGE ANY SLEET/FZRA OVER TO SNOW NEAR/AFTER MIDNIGHT IN THIS PART OF THE ADVISORY AREA. QPF AMOUNTS INDICATE A DUSTING TO 1 INCH OF SNOW WOULD BE MOST COMMON WITH HIGHEST AMOUNTS EAST OF I-65 AND NORTH OF I-40...WITH TRAVEL SEEING THE MOST IMPACTS DUE TO POTENTIALLY SNOWY BRIDGES AND OVERPASSES. LONGER DURATION OF PRECIP AND COOLER TEMP PROFILES SUGGEST NORTHERN CUMBERLAND PLATEAU COULD END UP WITH HIGHER SNOW ACCUMS...AND THIS WILL HAVE TO BE CLOSELY MONITORED AS THE EVENT UNFOLDS. PRECIPITATION WILL BE ENCOUNTERING A VERY DRY AIRMASS ALOFT TO THE NORTHWEST OF THE MID STATE...AND A SHARP NORTHWEST EDGE TO THE PRECIP SHIELD IS ANTICIPATED LIKELY SOMEWHERE ALONG A LINE FROM LINDEN TO LAFAYETTE...WITH LITTLE OR NO PRECIP AT ALL ANTICIPATED IN NORTHWEST ZONES. THIS BACK EDGE TO THE PRECIP GIVES THE FORECAST CONSIDERABLE BUST POTENTIAL FOR THE NORTHWEST COUNTIES WITHIN THE ADVISORY AREA. UNFORTUNATELY...THIS BACK EDGE TO THE PRECIP WILL ALSO LIKELY BISECT THE NASHVILLE METRO...SO NORTHWEST PORTIONS OF THE METRO AREA MAY SEE LITTLE OR NO PRECIPITATION WHILE SOUTHEAST SECTIONS ARE MORE IMPACTED. EVEN MORE UNCERTAIN ARE CONVECTIVE ELEMENTS WITH THE PRECIP AS SOUNDINGS DEPICT SOME ELEVATED INSTABILITY...SO IF STRONGER CONVECTION CAN FORM FZRA/ICE/SNOW AMOUNTS COULD BE HIGHER IN SOME LOCATIONS. LONG TERM... MAIN FORECAST FOCUS WAS ON WINTER WEATHER TONIGHT...SO FORECAST FOR REST OF THE WEEK RELIED HEAVILY ON THE 12Z GFS. APPEARS CLOUDS WILL FINALLY CLEAR ACROSS THE CWA BY TUESDAY AFTERNOON AS STRONG NORTHWEST FLOW DEVELOPS IN THE LOW LEVELS...BUT THIS WILL RESULT IN SEVERAL COLD DAYS FOR THE MIDDLE OF THE WEEK WITH LOWS IN THE TEENS NORTHWEST TO 20 ELSEWHERE AND HIGHS ONLY IN THE 30S AND 40S. WARMING TREND ANTICIPATED BY FRIDAY AS SURFACE RIDGE MOVES EAST AND SOUTHERLY FLOW DEVELOPS. COULD SEE A BIT OF A RAIN/SNOW MIX ON THE PLATEAU EARLY FRIDAY NIGHT...BUT EVENTUALLY ALL RAIN IS EXPECTED EVERYWHERE AS TEMPS WARM CONSIDERABLY INTO SATURDAY. STRONG CAA IN THE WAKE OF THE UPCOMING WEEKEND SYSTEM WILL BRING MUCH COLDER TEMPERATURES AND OUR NEXT CHANCE FOR LIGHT SNOW SATURDAY NIGHT...ALTHOUGH MAIN DEFORMATION BAND LOOKS TO STAY WELL NORTH OF THE MID STATE. && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR TNZ008>011- 027>034-056>066-075-077>080-093>095. && $$ 21
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
343 AM CST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CST TUE DEC 10 2013 CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER THE EAST PACIFIC...TROUGHING OVER CENTRAL AND EASTERN CANADA AND SOUTHWARD INTO THE UPPER MIDWEST. WITHIN THIS TROUGH...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST MINNESOTA WHILE ANOTHER SHORTWAVE COULD BE SEEN UPSTREAM IN CENTRAL ALBERTA. THE STRONG DPVA FORCING AHEAD OF THE POTENT SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND SOME MOISTURE HAS HELPED SPREAD CLOUDS ACROSS THE FORECAST AREA. IN ADDITION...LIGHT SNOW WAS MOVING ACROSS THE FORECAST AREA. ALSO ACCOMPANYING THE POTENT SHORTWAVE WAS A RELATIVELY DEEP SURFACE LOW CENTERED NEAR MINNEAPOLIS. THE COMBINATION OF THE CLOUDS AND STRENGTHENING SOUTHERLY WINDS AHEAD OF THE LOW HAVE HELPED TO BRING TEMPERATURES UP THROUGH THE NIGHT. MOST WIND CHILLS ARE ABOVE ADVISORY CRITERIA OF -20F...THUS WE WERE ABLE TO CANCEL TAYLOR/CLARK EARLY. SIMILARLY...ON THE BACK SIDE OF THE SURFACE LOW WHERE PRESSURES ARE RISING RAPIDLY...STRONG NORTHWEST WINDS ARE OCCURRING. THESE ARE ADVECTING IN A BRIEF SURGE OF ARCTIC AIR CHARACTERIZED BY 850MB TEMPS OF -20C PER RAP ANALYSIS. SKIES BEGIN TO CLEAR OUT QUICKLY TOO ON THE BACK SIDE OF THE LOW. THE POTENT SHORTWAVE IN MINNESOTA REMAINS PROGGED TO FLY THROUGH THE FORECAST AREA THIS MORNING...SUCH THAT IT IS ALREADY IN LOWER MICHIGAN BY 18Z. WHAT THIS MEANS IS WE SHOULD HAVE A BRIEF PERIOD OF SNOW FOR THE EARLY MORNING HOURS...AFFECTING THE MORNING COMMUTE. ONCE THE WAVE PASSES...EXPECTING WINDS TO CRANK UP OUT OF THE WEST AS PRESSURES RISE RAPIDLY. GUSTS ARE LIKELY TO RANGE 25-35 KT WITH THE PRESSURE RISE COMING IN...HIGHEST IN SOUTHEAST MN. SOME BLOWING AND DRIFTING OF ALL THE RECENT SNOW IS LIKELY. IT APPEARS BRISK WINDS WILL PERSIST UNTIL LATE IN THE DAY WHEN A SURFACE RIDGE BUILDS IN. THE BRISK WINDS WILL ALSO BRING IN COLDER AIR...CAUSING TEMPS TO FALL...DESPITE INCREASING SUNSHINE. THE CLEARING THIS AFTERNOON LOOKS TO BE SHORT-LIVED...HOWEVER. THE NEXT SHORTWAVE OVER ALBERTA IS PROGGED TO DROP DOWN INTO WESTERN IOWA BY 12Z WEDNESDAY. AS THIS OCCURS...A MID-LEVEL FRONTOGENESIS BAND WILL SET UP AHEAD OF IT. 10.00Z GFS/NAM/ECMWF/CANADIAN TRACK THIS BAND FROM SOUTH DAKOTA THIS AFTERNOON INTO FAR SOUTHERN MN AND NORTHERN IA THIS EVENING...AND FINALLY INTO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS OVERNIGHT. GIVEN GOOD MODEL CONSENSUS HAVE RAISED PRECIPITATION CHANCES UP TOWARDS 100 SOUTH OF A LINE FROM AUSTIN MN TO RICHLAND CENTER WI. MOISTURE IS LIMITED...ON THE ORDER OF 1 G/KG...BUT THE STRONG FRONTOGENESIS SHOULD BE ABLE TO SQUEEZE OUT A TENTH OF LIQUID. WITH SNOW TO WATER RATIOS ON THE ORDER OF 15-20 TO 1...THIS WILL YIELD A QUICK 1 TO 2 INCHES OF SNOWFALL. FINALLY...IN THE WAKE OF THAT FRONTOGENESIS BAND...THAT SHORTWAVE TROUGH LOOKS TO BRING DOWN ANOTHER SURGE OF ARCTIC AIR WITH IT. 850MB TEMPS AFTER BRIEFLY CLIMBING TO -14 TO -18C AHEAD OF THE BAND...FALL TO -18 TO -22C BY 12Z WEDNESDAY. A TIGHTENING SURFACE PRESSURE GRADIENT SHOULD YIELD INCREASING NORTH WINDS...ADDING A WIND CHILL FACTOR. WIND CHILL ADVISORIES HAVE BEEN ISSUED...STARTING TAYLOR/CLARK AT 06Z AND THEN SOUTHEAST MN AND OTHER WI COUNTIES NORTH OF I-90 AT 10Z. THE WIND ON TOP OF THE NEW SNOW MAY PRODUCE SOME BLOWING AND DRIFTING ACROSS NORTHEAST IA TOO LATE IN THE NIGHT. CLEARING ALSO LOOKS TO ACCOMPANY THE CHILLY AIR. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 343 AM CST TUE DEC 10 2013 PLAN ON A COLD WEDNESDAY. ARCTIC AIR IS FORECAST TO GET DRAGGED INTO THE FORECAST AREA AS THE SHORTWAVE TROUGH OVER WESTERN IA HEADS EAST. TEMPS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...OR EVEN TO ZERO ACROSS TAYLOR/CLARK COUNTIES. ON TOP OF THE COLD...A DECENT PRESSURE GRADIENT IN PLACE SHOULD KEEP A NORTHWEST BREEZE GOING...RESULTING IN WIND CHILLS FROM THE -10 TO -30F RANGE. THESE COLD WIND CHILLS LOOK TO PERSIST INTO WEDNESDAY EVENING BEFORE WINDS TURN SOUTHWEST ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS PASSAGE. TEMPERATURES ARE FORECAST TO CLIMB AFTER MIDNIGHT IN RESPONSE TO THIS SOUTHWEST WIND...AS WELL AS INCREASING MID/HIGH CLOUDS. THESE CLOUDS ARE ASSOCIATED WITH ISENTROPIC LIFT WELL DOWNSTREAM OF A SHORTWAVE IN MONTANA. ONE QUESTION MARK IS IF ANY SNOW CAN FORM FROM THIS ISENTROPIC LIFT. MODELS HAVE BEEN GOING BACK AND FORTH ON THIS...WITH THE 10.00Z ECMWF AND GFS NOW BASICALLY DRY FOR WEDNESDAY NIGHT AND THURSDAY...WHEREAS THE 10.00Z CANADIAN MAINTAINS SOME LIGHT PRECIP OVER THE AREA BETWEEN 06-12Z THU. FOR NOW KEPT A 20 PERCENT CHANCE GOING BETWEEN 06-12Z THURSDAY OVER THE NORTHEAST PORTION OF THE AREA WITH DRY CONDITIONS BEFORE AND AFTER. WITH A WARM ADVECTION PATTERN IN PLACE THURSDAY...TEMPERATURES EXPECTED TO BE MUCH WARMER...ON THE ORDER OF 15-20 DEGREES. FROM THURSDAY NIGHT INTO FRIDAY...THE UPPER FLOW IS PROGGED TO BECOME MORE ZONAL OVER THE NORTHERN U.S.. WHAT THIS DOES IS ALLOWS A FRONTOGENESIS ZONE TO SET UP FROM THE DAKOTAS INTO WISCONSIN. THIS FRONTOGENESIS FORCING MAY RESULT IN SOME LIGHT SNOW THE ENTIRE TIME...WITH THE BEST CHANCES STAYING MAINLY NORTH OF THE FORECAST AREA. DID HONOR SOME 20 PERCENT CHANCES NORTH OF I-94 THURSDAY NIGHT PER MODEL CONSENSUS. ALSO ON FRIDAY...A SOUTHERN STREAM SHORTWAVE TROUGH IS SUGGESTED TO MOVE INTO THE CENTRAL PLAINS. FRONTOGENESIS DOWNSTREAM OF THIS SHORTWAVE TROUGH MAY SPREAD LIGHT PRECIP INTO SOUTHERN SECTIONS FOR THE FORECAST AREA. FOR NOW KEPT THIS PRECIP OUT...BUT SOMETHING TO MONITOR. THE SOUTHERN STREAM SYSTEM WILL NEED EVEN MORE MONITORING AS WE HEAD INTO FRIDAY NIGHT AND SATURDAY. MODELS ARE SUGGESTING AN INVERTED SURFACE TROUGH ASSOCIATED WITH THIS SHORTWAVE MOVING THROUGH THE FORECAST AREA. INVERTED TROUGHS ARE KNOWN TO BRING SNOW...SO PRECIPITATION CHANCES HAVE BEEN RAISED FOR FRIDAY NIGHT AND SATURDAY. IT SHOULD BE NOTED...THOUGH...THAT THE BULK OF THE ACCUMULATING SNOW LOOKS TO STAY SOUTHEAST OF THE AREA. ANOTHER BRIEF COOL DOWN...BUT NOT AS COLD AS SEEN RECENTLY...IS SUGGESTED FOR SUNDAY WITH DRY CONDITIONS AS HIGH PRESSURE MOVES THROUGH. LIGHT WARM ADVECTION SNOWS ARE PROGGED FOR MONDAY AS ANOTHER NORTHERN STREAM SHORTWAVE TROUGH DROPS DOWN TOWARDS THE UPPER MIDWEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1100 PM CST MON DEC 9 2013 UPPER LEVEL SHORTWAVE WILL DRIVE SOUTHEAST ACROSS THE REGION DURING THE OVERNIGHT/EARLY MORNING HOURS...BRINGING LOWERING CIGS AND SOME -SN. SNOW LOOKS MOST LIKELY BETWEEN 09-14Z FOR KRST/KLSE WITH VSBY RESTRICTIONS DOWN TO 2SM...POSSIBLY LOWER FOR A BRIEF TIME. CURRENT OBSERVATIONS ACROSS THE DAKOTAS MOSTLY INDICATING MVFR CIGS WITH THIS SYSTEM. CAN/T RULE OUT SOME SUB 1 KFT CIGS...BUT GOING TO KEEP MVFR FOR NOW. WINDS WILL INCREASE FROM THE WEST BY 15Z AS THE SYSTEM/S SFC LOW SLIDES ACROSS WI. THERE IS SOME CONCERN OF BLSN AT KRST...BUT NOT EXPECTING MORE THAN 1/2 INCH OF FRESH SNOW...AND WHAT FELL YESTERDAY HAS ALREADY BLOWN AROUND. GOING TO LEAVE OUT OF THE FORECAST FOR NOW...BUT TRENDS WILL HAVE TO BE MONITORED. SOME 4-5SM ISN/T OUT OF THE QUESTION. LOOKING FOR CLEARING BY THE AFTERNOON...BUT ANOTHER UPPER LEVEL SHORTWAVE WILL BE DROPPING ACROSS IA STARTING TUE EVENING. CLOUDS WILL RETURN...WITH LOWER CIGS AND SOME -SN. GREATER CHANCES TO THE SOUTH...BUT KRST/KLSE APPEAR CLOSE ENOUGH TO THE NORTHERN FRINGE WHERE A FEW HOURS OF -SN AND MVFR CIGS ARE LIKELY FOR LATE EVENING/OVERNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR WIZ032>034-041>044. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST THURSDAY FOR WIZ017-029. MN...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR MNZ079- 086>088-094>096. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1050 PM CST MON DEC 9 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 247 PM CST MON DEC 9 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A BROAD AREA OF LOW PRESSURE MOVING NORTHEAST OVER NORTHERN ONTARIO AND A SURFACE RIDGE AXIS SHIFTING EAST OVER THE NORTHERN PLAINS. BETWEEN THE TWO SYSTEMS...WEST WINDS IS DRIVING ARCTIC AIR ACROSS THE STATE...AND TEMPERATURES ARE DROPPING ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. NO CHANGE IN THE START OF TIME OF WIND CHILL HEADLINES...AS THEY ARE ALREADY APPROACHING CRITERIA AT RHINELANDER. THE LEADING EDGE OF THIS ARCTIC AIR IS MARKED BY A BAND OF STRATO-CU AND ACCOMPANYING LIGHT SNOW SHOWERS/FLURRIES...WHICH IS NOW ENTERING NORTHEAST WISCONSIN. ANTICIPATE THE SNOW SHOWERS/FLURRIES TO DIMINISH LATER THIS AFTERNOON ONCE THE SUN GOES DOWN AND ANY DIURNAL INSTABILITY IS LOST. ATTENTION THEN TURNS TO A FAST MOVING CLIPPER SYSTEM WHICH IS DIVING SE OVER SOUTHERN SASKATCHEWAN THIS AFTERNOON. THE CLIPPER LOOKS DECENT ON SATELLITE IMAGERY AND THERE ARE PLENTY OF OBS OVER WESTERN NORTH DAKOTA AND EASTERN MONTANA SHOWING LIGHT TO MODERATE SNOW. SO THE FORECAST CONCERNS START OUT WITH WIND CHILLS TONIGHT...AND SNOW POTENTIAL WITH THE CLIPPER LATE TONIGHT INTO TUESDAY MORNING. TONIGHT...HIGH PRESSURE RIDGE AXIS WILL MOVE EAST INTO CENTRAL WISCONSIN THIS EVENING AND ACROSS EASTERN WISCONSIN OVERNIGHT. ALONG WITH THE LOSS OF DAYTIME HEATING...THIS WILL HELP SKIES CLEAR AND LIGHT SNOW/FLURRIES COME TO AN END LATE IN THE AFTERNOON OR EARLY THIS EVENING. ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION DURING THE EVENING...AND THE CLEARING SKIES WILL PROMOTE TEMPS FALLING QUICKLY WITH LOWS OCCURRING NEAR OR SHORTLY AFTER MIDNIGHT. THEN ALL EYES WILL BE ON A FAST MOVING CLIPPER PROGGED TO ENTER THE STATE LATE TONIGHT. THE LATEST MODEL RUNS HAVE TRENDED A FEW HOURS SLOWER...AND NOW START BRINGING IT INTO THE STATE AFTER 09Z. THE VORT WILL BRING EXCELLENT MID-LEVEL FORCING...SO WILL INCREASE POPS BY 12Z DESPITE A SEVERE LACK OF MOISTURE. WITH THE LATER ARRIVAL OF THE CLIPPER...WIND CHILL READINGS WILL REMAIN NEAR THE 20 BELOW CRITERIA OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THROUGH THE 12Z HOUR SO NO CHANGE IN HEADLINES ANTICIPATED. TEMPS WILL REBOUND SOMEWHAT WITH THE INCREASING CLOUDS OVERNIGHT. TUESDAY...THE CLIPPER WILL QUICKLY ADVANCE EAST ACROSS THE AREA TUESDAY MORNING. THE STRONG FORCING AND POCKET OF INSTABILITY IN THE MID-LEVELS SHOULD BRING A FEW TENTHS OF DRY FLUFFY SNOW ACROSS THE ENTIRE FORECAST AREA BEFORE IT RAPIDLY PULLS OUT BY LATE IN THE MORNING OR EARLY AFTERNOON. ANOTHER SURGE OF ARCTIC AIR WILL FOLLOW IN THE WAKE OF THE CLIPPER...WITH STEEPENING LOW LEVEL LAPSE RATES AND ENHANCED LOW LEVEL RH. WOULDNT BE SURPRISED TO SEE INSTABILITY SNOW SHOWERS/FLURRIES REDEVELOP IN THE AFTERNOON...SIMILAR TO THE SNOW SHOWERS ONGOING TODAY. WILL LET THE NEXT SHIFT EVALUATE BEFORE ADDING THEM TO THE FORECAST. HIGHS FROM THE MIDDLE SINGLE DIGITS NORTH TO THE MIDDLE TEENS EAST. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 247 PM CST MON DEC 9 2013 COLD TEMPERATURES/WIND CHILLS AND PCPN CHANCES ARE THE MAIN FCST CONCERNS. A REINFORCING SHOT OF ARCTIC AIR WILL BE IN PLACE TUES NGT INTO WEDS...WITH H8 TEMPS OF -20 TO -25 C OVER THE FORECAST AREA. LOW- LEVEL WINDS WILL BE WEST-NORTHWEST...SO LAKE EFFECT IMPACT WILL BE MINIMAL...WITH JUST A FEW SNOW SHOWERS OR FLURRIES EXPECTED OVER VILAS COUNTY. A S/W TROF AND THE RRQ OF A JET STREAK WILL QUICKLY SWEEP THROUGH THE SOUTHERN PART OF GRB CWA ON TUES NGT...SO KEPT CHC POPS OVER C/EC WI. CLOUDS ASSOCIATED WITH THIS SYSTEM AND ANY LAKE-INDUCED CLOUDS OVER THE FAR NORTH COULD HAVE A BIG IMPACT ON MIN TEMPS. USED A BLEND OF THE PREV FCST...ECMWF AND A FEW OTHER TOP PERFORMING GUIDANCE SETS...AND MADE A FEW TWEEKS TO ACCOUNT FOR CLOUD TRENDS. WILL HAVE COLDEST MIN TEMPS (-15 TO -17 F) IN THE TOMAHAWK/RHINELANDER/CRANDON REGION...WITH SINGLE DIGITS BELOW ZERO OVER OUR SOUTHERN/EASTERN COUNTIES...EXCEPT SINGLE DIGITS ABOVE ZERO ALONG THE LKSHR. HIGH TEMPS ON WEDS WILL BE IN THE 5 BELOW TO 5 ABOVE RANGE IN MOST AREAS...COLDEST OVER NC WI. WIND CHILLS LOOK LIKE THEY WILL DROP INTO THE -20 TO -30 RANGE NORTHWEST OF A LINE FROM ISW-IMT TUES NGT INTO WEDS...AND OVER MOST OF THE CWA ON WED NGT...SO ADDITIONAL WIND CHILL ADVISORIES MAY BE NEEDED. WAA WILL DEVELOP LATE WEDS NGT INTO THURSDAY...AND WILL PROBABLY GENERATE SOME LIGHT SNOW OR FLURRIES. SOME MODERATION IN TEMPS IS ANTICIPATED...WITH HIGHS REACHING THE UPPER SINGLE DIGITS AND TEENS. THE ARCTIC BAROCLINIC ZONE WILL RESIDE OVER THE REGION THROUGH MUCH...IF NOT ALL...OF THE EXTENDED FORECAST. TEMPERATURES WILL REMAIN BLO NORMAL. WITH STRONG WEST-NORTHWEST FLOW ALOFT IN PLACE DURING THE PERIOD...SEVERAL JET STREAKS/SHORT-WAVE TROFS WILL PASS THROUGH THE GREAT LAKES REGION. THE RRQ OF A JET STREAK WILL PASS THROUGH THE REGION THU NGT AND FRI...AND MODELS ARE HINTING AT AN INVERTED SFC TROF AFFECTING THE REGION FRI NGT/SAT... AND POSSIBLY LINGERING OVER THE RGN INTO SUNDAY. ANY OF THESE DISTURBANCES COULD PRODUCE LIGHT SNOW OR FLURRIES...SO ALMOST EVERY PERIOD OF THE FCST HAS SLGT CHC/CHC POPS. HOPEFULLY IN THE NEXT FEW DAYS WE WILL BE ABLE TO BETTER DEFINE WHICH OF THESE SYSTEMS WILL HAVE THE MOST IMPACT ACROSS THE REGION. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1035 PM CST MON DEC 9 2013 WHILE A RIDGE OF HIGH PRESSURE SLIDES EAST OF THE REGION OVERNIGHT A CLIPPER SYSTEM WILL APPROACH THE STATE. MID TO HIGH LEVEL CLOUDS WILL SWEEP OVER THE REGION FOR THE EARLY MORNING HOURS. THEN A PERIOD OF MVFR CIGS WITH PERHAPS A 2 HOUR PERIOD IFR VSBYS DUE TO SNOW SHOWERS AND BLSN MAY BE ASSOCIATED WITH ANOTHER ARCTIC COLD FRONT PASSAGE. GUSTY WEST WINDS WITH AREAS OF BLSN WILL THEN CONTINUE FOR THE REST OF TUESDAY BEFORE DIMINISHING LATE IN THE DAY FROM WEST TO EAST ALONG WITH IMPROVING CIGS TO VFR CONDITIONS BY TUESDAY NIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ005-010>013- 018>021-030-031-035>037. && $$ SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1025 AM EST TUE DEC 10 2013 .SYNOPSIS... LOW PRESSURE TRACKING SOUTH OF NEW ENGLAND TODAY WILL SPREAD ACCUMULATING SNOWS TO CONNECTICUT... RHODE ISLAND AND SOUTHEAST MASSACHUSETTS LATER THIS MORNING AND AFTERNOON. AN ARCTIC AIRMASS OVER SPREADS SOUTHERN NEW ENGLAND WEDNESDAY NIGHT INTO FRIDAY. A LOW PRESSURE SYSTEM WILL LIKELY BRING A WINTRY MIX OF PRECIPITATION THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1030 AM UPDATE... OVERALL THINKING OF THE FORECAST REMAINS ON TRACK FOR THIS MORNING AND THE AFTERNOON HOURS. SNOW HAS OVERSPREAD ACROSS MUCH OF THE REGION THIS MORNING...STAYING SOUTH OF THE ROUTE 2. LATEST SOUNDINGS AT CHH AND GYX SHOW A GOOD AMOUNT OF DRY AIR AT 800 MB. BELIEVE THAT IT MAKE TAKE A BIT FOR THE COLUMN TO MOISTEN UP NORTH OF ROUTE 2. HOWEVER ONCE WHEN COLUMN IS SATURATED BELIEVE FLURRIES/LIGHT SNOW WILL FALL. RADAR SHOWING 2 BANDS MOVING ACROSS THE REGION AT THIS TIME. THE FIRST ONCE IS ACROSS HFD TO ORH WHILE THE SECOND MORE PRONOUNCED ONE IS ACROSS SOUTHERN CT INTO SOUTHERN RI AND STARTING TO MOVE INTO FMH. BOTH OF THESE BANDS WILL REDUCE VISIBILITIES AND INCREASE THE SNOWFALL RATES CLOSE TO AN INCH PER HOUR. AS MENTIONED BY PREV FORECASTER THIS IS A QUICK MOVING SYSTEM SO BELIEVE THAT FROM NOW TIL AROUND 3-4PM WILL BE THE BEST TIMEFRAME FOR SNOW TO ACCUMULATE. MODELS INDICATE THAT SNOW WILL BE LIGHTENING UP AND TAPERING OFF JUST AS THE EVENING COMMUTE GETS GOING. SNOW MAY LINGERING ACROSS THE CAPE TIL ABOUT 00Z. BECAUSE TEMPS ARE FALLING BELOW FREEZING THROUGHOUT THE DAY...ANY UNTREATED ROADS WILL BE SLIPPERY. BELIEVE THAT SOUTH OF THE PIKE HAS THE BEST CHANCE OF SEEING ANY ACCUMULATIONS...WHERE THE HIGHER ACCUMS WILL BE ACROSS CT...RI AND SE MASS OF 1-3 INCHES. MAIN CONCERN IS THE AMOUNT OF BANDING ACROSS THE IMMEDIATE SOUTH SHORE. THE LATEST NAM AND HRRR MODELS CONTINUE TO KEEP THE HIGHER QPF AMOUNTS HUGGING THE SOUTH COAST. HOWEVER THERE CONTINUES TO BE EXCELLENT MOISTURE IN THE SNOW GROWTH REGION WHERE A STRONG DEFORMATION ZONE MAY DEVELOP. WE WILL NEED TO WATCH THE LATEST RADAR TRENDS TO MONITOR FOR THIS BANDING POTENTIAL. IF THIS DOES OCCUR...THE BEST LOCATION WILL BE ALONG THE SOUTH COAST...WHICH MAY INCREASE THE SNOWFALL A FEW MORE INCHES WITH SNOWFALL RATES NEARING OVER AN INCH AN HOUR. DAYTIME HIGHS WILL GENERALLY BE IN THE 30S...THOUGH TEMPS WILL START TO FALL BY MIDDAY ACROSS THE SNOW AREAS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... TONIGHT... EXPECT PRECIP TO TAPER OFF ACROSS THE REGION BY 01Z-02Z...THEN VERY COLD AIR WORKS INTO THE REGION. EXPECT VERY GOOD MIXING WITH H85 TEMPS DROPPING TO -12C TO -14C OVERNIGHT...SO EXPECT W-NW WINDS TO PICK UP NEAR THE COAST AROUND OR AFTER MIDNIGHT. HIGHEST GUSTS WILL BE OVER THE OUTER CAPE AND NANTUCKET. SKIES WILL BECOME MAINLY CLEAR AS TEMPS DROP TO THE MID TEENS WELL INLAND TO THE 20S ALONG THE IMMEDIATE COAST. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * ARCTIC AIR THU AND FRI * POTENTIAL WINTRY PRECIPITATION SAT/SUN WILL BE BRIEF HERE GIVEN THE EXPECTED ACTIVE WINTER WEATHER TODAY. 00Z GEFS AND ECENS ENSEMBLES ARE IN VERY GOOD AGREEMENT ON THE LARGE SCALE FLOW ALONG WITH THE TIMING AND SMALLER SCALE DETAILS. AN ACTIVE PATTERN CONTINUES THIS PERIOD WITH AN ARCTIC FRONTAL PASSAGE WED NGT OR EARLY THU. BOTH ENSEMBLE DATA SETS /GEFS AND ECENS/ SUPPORT -20C AIRMASS /-2 STD FROM CLIMO/ MOVING ACROSS SOUTHERN NH AND NORTHERN MA THU! THIS WILL LIKELY BE THE COLDEST AIRMASS OF THIS EARLY WINTER SEASON SO FAR. THIS COLD DRY AIRMASS LINGERS INTO FRI AS WELL. HIGHS THU AND FRI WILL ONLY REACH INTO THE 20S! NORMAL HIGH THIS TIME OF YEAR IS IN THE U30S TO L40S. THEN THIS WEEKEND ENSEMBLES REMAIN IN VERY GOOD AGREEMENT WITH SOUTHERN STREAM SYSTEM EXITING THE GULF STATES AND TRACKING NORTHEAST TO THE MID ATLC LATE SAT. COLD AIRMASS LINGERS OVER NEW ENGLAND SAT WHICH WILL SUPPORT PTYPE ISSUES FOR THE REGION. BY 12Z SUNDAY BOTH THE 00Z GEFS AND 12Z ECENS SUPPORT A COASTAL HUGGER WITH LOW PRES TRACKING ALONG OR NEAR THE SOUTHERN NEW ENGLAND COAST. AT THIS EARLY STAGE THIS SCENARIO WOULD SUGGEST A WINTRY MIX TO RAIN FOR THE COASTAL PLAIN INCLUDING PVD/BOS CORRIDOR. HOWEVER IF THIS STORM TRACK VERIFIES SHALLOW COLD AIR WOULD BE DIFFICULT TO SCOUR OUT ACROSS THE INTERIOR. THUS THERE IS A RISK FOR SIGNIFICANT ACCUMULATION OF A WINTRY MIX WELL INLAND...ESPECIALLY GIVEN THIS SOUTHERN STREAM SYSTEM WILL HAVE PLENTY OF QPF. NEVERTHELESS THIS POTENTIAL EVENT IS STILL 4-5 DAYS AWAY SO ITS WAY TOO EARLY TO NAIL DOWN SPECIFICS. NONETHELESS THE POTENTIAL FOR SIGNIFICANT WINTER STORM THIS WEEKEND EXISTS. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR TERM /THROUGH TONIGHT/... MODERATE CONFIDENCE...THOUGH LOW CONFIDENCE ON EXACT TIMING OF LOWERING CONDITIONS. 1030 AM UPDATE... TODAY...SNOW WILL CONTINUE TO OVERSPREAD ACROSS ALL SITES THIS MORNING. EXPECT VSBYS AT OR BELOW 1SM AND LIFR CIGS IN POCKETS OF SN. EXPECT LOWEST CONDITIONS NEAR AND S OF THE MASS PIKE WITH IFR- VLIFR. ACROSS N MA/S NH...SHOULD SEE MAINLY VFR...THOUGH SOME MVFR-IFR MAY WORK INTO NE MA /CAPE ANN AREA/ AROUND MIDDAY. WIDESPREAD ACCUMS OF 1-3 INCHES WITH LOCALLY HIGHER AMOUNTS ESPECIALLY ALONG THE SOUTH COAST INCLUDING THE CAPE AND ISLANDS. SNOW MOVES EAST INTO EVENING AND TERMINALS GRADUALLY IMPROVE BACK TO VFR. TONIGHT...VFR FOR MOST AREAS. MVFR-IFR CIGS/VSBYS MAY LINGER OVER CAPE COD AND THE ISLANDS THROUGH 03Z-04Z...THEN SHOULD IMPROVE. W-NW WINDS GUSTING TO 25-30 KT ON THE OUTER CAPE AND ISLANDS. KBOS TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT. KBDL TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT. OUTLOOK...WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE. MAINLY VFR THRU THE PERIOD. ONLY CAVEAT WILL BE THE POSSIBILITY OF LOCALIZED MVFR CONDITIONS IN SOME OCEAN EFFECTS -SHSN/SHRA FOR CAPE/ISLAND TERMINALS WITH THE BEST CHANCES WED NIGHT AND THU. STRONG NW WIND GUSTS ALSO POSSIBLE WED INTO WED NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. TODAY...EXPECT LIGHT W-NW WINDS EARLY...WITH GUSTS INCREASING TO AROUND 20 KT THIS AFTERNOON. SNOW WILL MOVE IN FROM W-E WITH REDUCED VSBYS DOWN TO 1/2 MILE OR LESS. SEAS AROUND 5 FT ON THE EASTERN OUTER WATERS EARLY EXPECTED TO SUBSIDE BY MIDDAY. TONIGHT...SNOW WILL END EARLY THIS EVENING...BY AROUND 03Z ON THE EASTERN OUTER WATERS. W-NW WINDS WILL INCREASE AS COLDER AIR WORKS ACROSS THE WATERS...WITH GUSTS TO GALE FORCE FOR A TIME OVERNIGHT ON THE OUTER WATERS. GALE WARNINGS UP THERE...WITH SMALL CRAFTS FOR THE REMAINING WATERS. SEAS WILL ALSO BUILD...UP TO 6-8 FT ON THE OUTER WATERS LATE. OUTLOOK...WEDNESDAY THROUGH FRIDAY...HIGH CONFIDENCE. A PROLONGED PERIOD OF WNW WINDS 25 KT OR HIGHER THROUGH THE PERIOD APPEARS LIKELY. THERE IS ALSO THE LOW PROBABILITY THAT OCCASIONAL GALE FORCE WIND GUSTS OCCUR THU BEHIND ARCTIC FRONTAL PASSAGE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR CTZ002>004. MA...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MAZ017>024. NH...NONE. RI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR RIZ001>008. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR ANZ231>235-237. SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 2 AM EST WEDNESDAY FOR ANZ230-236. GALE WARNING FROM 9 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR ANZ250-254>256. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR ANZ251. && $$ SYNOPSIS...NOCERA/EVT NEAR TERM...DUNTEN SHORT TERM...EVT LONG TERM...NOCERA AVIATION...NOCERA/DUNTEN/EVT MARINE...NOCERA/EVT
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1019 AM EST TUE DEC 10 2013 .SYNOPSIS... WEAK LOW PRESSURE PASSING SOUTHEAST OF LONG ISLAND THROUGH THIS AFTERNOON. HIGH PRESSURE WILL THEN BUILD FROM THE WEST TONIGHT...FOLLOWED BY AN APPROACHING COLD FRONT ON WEDNESDAY. THE FRONT WILL MOVE ACROSS WEDNESDAY NIGHT...WITH HIGH PRESSURE BUILDING IN FROM THE SOUTH AND WEST THROUGH THE END OF THE WEEK. A COASTAL STORM WILL LIKELY IMPACT THE REGION THIS WEEKEND...WITH HIGH PRESSURE RETURNING EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN STORY TODAY WILL BE MODERATE TO HEAVY SNOW. WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR ENTIRE FORECAST REGION. ANY DRIER LOW LEVELS AND TEMPS A FEW DEGREES BELOW FREEZING QUICKLY WET BULB TO NEAR FREEZING OUT EAST FOR THE TWIN FORKS OF LONG ISLAND AND SOUTHEAST CT. TEMPS LOWER A DEGREE AND STAY FREEZING OR BELOW THEREAFTER. THEREFORE SNOW WILL ACCUMULATE. FORCING FOR THIS IS WELL ESTABLISHED DESPITE THE LACK OF A STRONG SURFACE LOW. DEEP TROUGH IN THE MID LEVEL WITH POSITIVE VORTICITY ADVECTION AHEAD OF IT REALLY WILL ENHANCE PRECIP THROUGH THE 18Z HOUR. RUC13 SHOWS DECENT OMEGA WITHIN THE SNOW GROWTH ZONE BETWEEN -10 AND -20 DEGREES C WITH THE MORNING MODERATE TO HEAVY SNOW MOVING ACROSS. THE FORCING AND HEAVIEST SNOW IS CONCENTRATED ALONG URBAN NE NJ...NYC...SOUTHERN LOWER HUDSON VALLEY...SOUTHERN CONNECTICUT...WESTERN LONG ISLAND CORRIDOR. ADDITIONAL SNOW WITH GENERALLY LIGHT ACCUMULATIONS EXPECTED AFTER 18Z-19Z WITH ADDITIONAL FORCING FROM POSITIVE VORTICITY ADVECTION WITH TROUGH ALTHOUGH AMPLITUDE IS NOT AS HIGH. OVERALL FOR STORM TOTAL...SNOW AMOUNTS OF 3 TO 5 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN NE NJ...NYC...SOUTHERN LOWER HUDSON VALLEY...MOST OF SOUTHERN CT...AND MOST OF LONG ISLAND. ELSEWHERE...3 TO 4 INCHES OF SNOW. AGAIN...LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE. ADDITIONAL SNOW WITH GENERALLY LIGHT ACCUMULATIONS EXPECTED AFTER 18Z-19Z WITH ADDITIONAL FORCING FROM POSITIVE VORTICITY ADVECTION WITH TROUGH ALTHOUGH AMPLITUDE IS NOT AS HIGH. CONSENSUS OF THE MODELS TAKES THE LOW TO THE SE OF THE 40N/70W BENCHMARK BY EARLY THIS AFTERNOON. SO THIS...COUPLED WITH ONGOING LOW LEVEL COLD AIR ADVECTION WILL YIELD A P-TYPE OF SNOW ACROSS THE ENTIRE CWA. TEMPERATURES ARE CRITICAL TO THIS FORECAST - EXPECT GENERALLY SLOWLY FALLING TEMPERATURES THIS MORNING ONCE THE PRECIPITATION BEGINS...AND THIS WILL CONTINUE INTO THIS AFTERNOON WITH THE WET-BULBING OF TEMPERATURE - ESPECIALLY NOTING THAT LOWER DEWPOINT AIR IS BEING ADVECTED IN THE LOWER LEVELS. THIS WILL PLACE NORTHERN ZONES IN THE MID TO UPPER 20S AND SOUTHERN ZONES AROUND 30. THIS TEMPERATURE FALL OFF WILL ALLOW FOR RATIOS OF AROUND 12:1 ACROSS SOUTHERN AREAS AND 15-20:1 INLAND. RAP/NAM/GFS/SREF/ECMWF ALL SHOW AN AREA OF FAIRLY STRONG FRONTOGENESIS FROM 700-500 HPA CROSSING THE AREA THIS MORNING TO EARLY AFTERNOON...WITH THE CORE IF IT TRACING FROM JUST W OF NYC ON NE INTO S CT. GIVEN THE RATIO AND THE BANDING - APPEARS EVEN WITH QPF AROUND 1/3 OF AN INCH ACROSS SOUTHERN ZONES + AND AROUND .2" ACROSS NORTHERN ZONES...EXPECT A 3-5" SNOWFALL ACROSS THE ENTIRE CWA WITH LOCALLY HIGHER AMOUNTS UNDER STRONGER SNOW BANDS. THE SNOW WILL MOVE THROUGH THE REGION FAIRLY QUICKLY...MAINLY THROUGH 21Z. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... CONDITIONS QUICKLY CLEAR OUT ACROSS MOST OF THE AREA THIS EVENING AS THE LOW PULLS OUT WITH WEAK RIDGING BUILDING IN ALOFT THE EXCEPTION WILL BE LAKE EFFECT CLOUDS SETTING UP ACROSS FAR NW AREAS. BLUSTERY WINDS TONIGHT ACROSS ALL BUT WESTERN INTERIOR AREAS IN THE WAKE OF THE STORM...WITH GUSTS OF 20-30 MPH. USED THE MINIMUM OF MAV/MET/NAM 2-METER TEMPERATURES FOR LOWS - WITH VALUES AROUND 10 DEGREES BELOW NORMAL. DID NOT UNDERCUT GUIDANCE WITH SNOW COVER DUE TO WINDS BEING A LIMITING FACTOR. WIND CHILLS OVERNIGHT WILL RANGE FROM 5 TO 15 DEGREES - COLDEST N OF NYC AND WARMEST OVER EASTERN LONG ISLAND. WEAK RIDGING EXITS TO THE EAST WEDNESDAY WITH A WSW FLOW SETTING UP ALOFT. THIS SHOULD KEEP MOST IF NOT ALL LAKE EFFECT FLURRIES/-SHSN TO THE N OF THE AREA. MIXING WILL BE LIMITED TO AROUND 925-900 HPA SO HIGHS WILL STRUGGLE TO REACH THE 30 DEGREE MARK IN MOST LOCATIONS...WITH COASTAL SE CT AND THE TWIN FORKS STRUGGLING TO REACH FREEZING. THESE HIGHS ARE CONSISTENT WITH A BLEND OF MIXING DOWN FROM 925 HPA...EXCEPT 900 HPA WELL INLAND...WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV/MET GUIDANCE...AND ARE AROUND 15 DEGREES BELOW NORMAL. WIND CHILLS WEDNESDAY WILL MAINLY BE IN THE TEENS...WITH SOME AROUND 20 ACROSS COASTAL SE CT AND THE TWIN FORKS. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... THE H5 FLOW ACROSS THE EASTERN US WILL START WITH A BROAD TROUGH AND BECOME ZONAL BY THE WEEKEND. MEANWHILE A SPLIT FLOW OUT WEST WILL PHASE WITH TIME AS THE NORTHERN BRANCH DIGS FROM THE PAC NW TO THE ROCKIES AND PLAINS STATES. THIS PHASING ENERGY WILL BE THE AREA TO WATCH THROUGH THE REMAINDER OF THE WEEK AS SIGNALS FOR A COASTAL STORM THIS WEEKEND ARE APPARENT. AT THE SFC...A COLD FRONT WILL TRAVERSE THE AREA WED NIGHT. DEEP LAYERED MOISTURE IS LACKING...THEREFORE EXPECT IT TO PASS DRY. A FEW LAKE EFFECT FLURRIES MAY MAKE IT INTO FAR NW ORANGE COUNTY. COLD WEATHER WILL CONTINUE THROUGH THE END OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE FREEZING MARK ON THU (H85 TEMPS AROUND -15C). SIDED WITH THE COLDER GUIDANCE WITH THE SNOW PACK EXPECTED TO REMAIN ON THE GROUND. LOWS WED NIGHT WILL GENERALLY BE IN THE LOWER TEENS INLAND TO AROUND 20 IN METRO NY/NJ. THU NIGHT WILL BE A TAD COLDER WITH LESS CLOUD COVER WITH TEENS AT THE COAST AND SINGLE DIGITS INLAND. WIND CHILLS BOTH NIGHTS WILL DROP INTO THE SINGLE DIGITS ACROSS THE AREA...AND COULD FALL BELOW ZERO THU NIGHT ACROSS INTERIOR ZONES. CONDS WILL REMAIN DRY THROUGH FRI WITH HIGH PRES NOSING IN FROM THE S AND W. AS FOR THE WEEKEND SYSTEM...THE INITIAL SFC LOW ASSOCIATED WITH THE SOUTHERN BRANCH OF THE JET STREAM IS FORECAST TO DEVELOP IN THE LEE OF THE ROCKIES AND MOVE ACROSS THE SOUTHERN PLAINS FRI AND FRI NIGHT. AS THE NORTHERN STREAM ENERGY PHASES WITH IT AND MOVES TOWARDS THE MID ATLANTIC COAST...THE SYSTEM WILL STRENGTHEN AND TRACK FROM THE MID ATLANTIC COAST JUST S AND E OF LI BEFORE LIFTING TOWARDS NOVA SCOTIA. THE DEVIL IS IN THE DETAILS AND THERE IS A 6-12 HOUR DIFFERENCE IN THE TIMING BETWEEN THE OPERATIONAL EC...CMC AND GFS. THE TRACK IS THE MOST CONSISTENT ASPECT OF THE SYSTEM AND WITH A DECENT HIGH TO THE NE IT SHOULD BE COLD ENOUGH AT THE ONSET FOR SNOW WITH A GRADUAL WARMING OF THE ATMOSPHERE. THE TIMING AND EXTENT OF THE CHANGEOVER STILL NEEDS TO BE RESOLVED. THE GFS IS MUCH WARMER THAN THE EC TO START WHICH IS A KNOWN BIAS OF THE MODEL. IT IS LIKELY ERODING THE COLD AIR TOO QUICKLY. THIS WILL ULTIMATELY HAVE IMPACTS ON P-TYPE...SO HAVE LOW CONFIDENCE IN THE DETAILS OF THE CURRENT FORECAST. HIGH PRES THEN BUILDS TOWARDS THE AREA FOR THE START OF THE NEW WORK WEEK WITH DRY BUT COLD AND POTENTIALLY GUSTY CONDS. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... LOW PRESSURE PASSING TO THE SOUTH WILL BRING VARYING IFR/LIFR CONDITIONS THROUGH MIDDAY...WITH IMPROVING CONDITIONS THROUGH THE AFTERNOON INTO TONIGHT. HEAVIEST SNOW EXPECTED INTO EARLY AFTN...TAPERING OFF FROM WEST TO EAST DURING THE 17Z-19Z TIME PERIOD. IFR CIGS...WITH VARYING VIS BETWEEN 1/4SM-3/4SM PSBL WITH THE SNOW. LIGHT SNOW WITH IFR CIGS/VIS THROUGH THE AFTN...ENDING WEST TO EAST BETWEEN 19-21Z. COULD SEE CIGS/VIS IMPROVE +1-2 HOURS SOONER THAN IN TAF OVER ENTIRE AREA. RUNWAY SNOWFALL TOTALS GENERALLY 3-4 INCHES. CLEARING SKIES AND VFR CONDITIONS AFTER 21Z. LIGHT W-NW WINDS THIS MORNING...GENERALLY 8 KTS OR LESS. WINDS INCREASE FROM THE WNW AFTER 21Z...WITH GUSTS BETWEEN 20-25 KTS LASTING INTO TONIGHT. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: BRIEF PERIODS OF VIS DOWN TO 1/4SM PSBL THROUGH 17Z WITH +SN. WINDS MAY BE LIGHT AND VRB THRU 18Z. KLGA FCSTER COMMENTS: BRIEF PERIODS OF VIS DOWN TO 1/4SM PSBL THROUGH 17Z WITH +SN. KEWR FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN TEMPO GROUP. KTEB FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN TEMPO GROUP. KHPN FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN TEMPO GROUP. KISP FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN TEMPO GROUP. .OUTLOOK FOR 15Z WED THROUGH SAT... .WED...VFR. W WINDS G20-25KT. .THU...VFR. W-NW G20KT. .FRI...VFR. .SAT...MVFR OR LOWER CONDITIONS WITH MIXED WINTRY PRECIP. && .MARINE... AFTER A LULL WITH SUB-SCA CONDITIONS...WIND GUSTS INCREASE LATE THIS AFTERNOON TO SCA LEVELS ON THE COASTAL OCEAN WATERS LATE THIS AFTERNOON. SINCE THIS SHOULD BE ONLY A COUPLE OF HOURS BEFORE THE GALE WARNING STARTS...IT WILL NOT BE OF LONG ENOUGH DURATION TO WARRANT AN SCA. GUSTS TO GALE FORCE ARE EXPECTED TONIGHT ON THE COASTAL OCEAN WATERS...WITH GUSTS TO SCA LEVELS ELSEWHERE IN THE WAKE OF THE DEPARTING LOW. THE SCA LEVEL GUSTS WILL LIKELY CONTINUE ON ALL WATERS WEDNESDAY. GALE WARNING IN EFFECT FOR THE COASTAL OCEAN WATERS FOR TONIGHT AND A SMALL CRAFT ADVISORY FOR THE REMAINDER OF THE WATERS. WITH CONFIDENCE NOT QUITE AT 80 PERCENT...OPTED NOT TO EXTEND THE SCA INTO WEDNESDAY ON THE NON-OCEAN ZONES. SCA MAY NEED TO BE CONTINUED INTO PART OF WED NIGHT WITH WINDS AND SEAS DIMINISHING. AFTER A BRIEF LULL ON THU/THU NIGHT...CAA IS EXPECTED TO BRING WINDS AND SEAS BACK UP WITH SCA LIKELY NEED ON AT LEAST THE OCEAN WATERS FRI. CONDS THEN SHOULD REMAIN AT SUB-ADVY LEVELS UNTIL THE COASTAL SYSTEM THIS WEEKEND ALTHOUGH TIMING IS UNCERTAIN AT THIS TIME. STRONG GALES ARE POSSIBLE ON THE BACKSIDE OF THE SYSTEM. && .HYDROLOGY... WILL RECEIVE FROM .1 TO .4 INCHES OF LIQUID EQUIVALENT TODAY...ALMOST ALL OF IT IN THE FORM OF SNOW. NO HYDROLOGIC ISSUES ARE EXPECTED. IT SHOULD THEN BE DRY THROUGH FRIDAY. THERE IS THE POTENTIAL FOR SIGNIFICANT PRECIPITATION THIS WEEKEND IN ASSOCIATION WITH A COASTAL LOW PRES SYSTEM. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR CTZ005>012. NY...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR NYZ068-070>075-078>081-176>179. WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ067-069. NJ...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NJZ002-004-006-103>108. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR ANZ330-335-338-340-345. GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR ANZ350-353-355. && $$ SYNOPSIS...24/MALOIT NEAR TERM...MALOIT/JM SHORT TERM...MALOIT LONG TERM...24 AVIATION...SEARS MARINE...24/MALOIT/JM HYDROLOGY...24/MALOIT EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
707 AM EST TUE DEC 10 2013 .SYNOPSIS... LOW PRESSURE TRACKING SOUTH OF NEW ENGLAND TODAY WILL SPREAD ACCUMULATING SNOWS TO CONNECTICUT... RHODE ISLAND AND SOUTHEAST MASSACHUSETTS LATER THIS MORNING AND AFTERNOON. AN ARCTIC AIRMASS OVERSPREADS SOUTHERN NEW ENGLAND WEDNESDAY NIGHT INTO FRIDAY. A LOW PRESSURE SYSTEM WILL LIKELY BRING A WINTRY MIX OF PRECIPITATION THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 7 AM UPDATE... CLOUD TOPS COOLING ACROSS THE NORTHEAST ALONG WITH A BAROCLINIC LEAF FORMING FROM OH-WESTERN PA INTO NY AS SHORT WAVE TROUGH RACES NE THROUGH THE EASTERN US LONG WAVE TROUGH. SNOW NOT REACHING THE GROUND YET ACROSS SOUTHERN NEW ENGLAND AS SURFACE OBS INDICATE NEAREST SNOWFALL OCCURRING OVER EASTERN PA AT 7 AM. LATEST TRENDS FROM 06Z NAM/GFS AND 03Z SREF SUGGEST A SOUTHWARD TREND IN QPF. LATEST RUNS OF HRRR ALSO SUPPORT THIS IDEA ALONG WITH MESOSCALE SNOW BANDS FRAGMENTED AND DISORGANIZED. NOT TOTALLY UNREALISTIC AS WAVE REMAINS OPEN AND VERY PROGRESSIVE. THUS OUR SNOWFALL PREDICTIONS ACROSS NORTHERN CT INTO NORTHERN RI MAY BE TOO HIGH IF MID LEVEL FGEN AND MESOSCALE SNOW BANDS SET UP FARTHER SOUTHEAST. WE WILL LEAVE FORECAST AS IS FOR NOW BUT ALERT ONCOMING SHIFT TO MONITOR LATEST TRENDS. EARLIER DISCUSSION BELOW. ================================================================== NOTING PRECIP QUICKLY BLOSSOMING ACROSS E PA/CENTRAL AND NY STATE OVER THE LAST COUPLE OF HOURS ON NE 88D REGIONAL MOSAIC RADAR. ALSO SEE COOLING CLOUD TOPS IN SAME GENERAL AREA ON IR SATELLITE. HOWEVER...FEW IF ANY REPORTS FROM ASOS/S IN THOSE AREAS AT 09Z. TEMP/DEWPT SPREADS ARE ABOUT 5-8 DEGS...STILL A BIT WIDE FOR DEVELOPING PRECIP ALOFT. SHORT RANGE MODELS CONTINUE TO SIGNAL VERY GOOD LOW LEVEL MOISTURE AND LIFT WORKING UP THE COAST WELL N OF WEAK DEFORMATION ZONE MOVING OFF THE MID ATLC COAST...ALONG WITH DIGGING H5 TROUGH MOVING QUICKLY E OUT OF THE UPPER PLAINS. ALL ARE SHOWING QUICKLY DEVELOPING AREA OF PRECIP...BUT STILL SOME QUESTIONS AS TO WHERE THE CORE OF THE QPF WILL ULTIMATELY. APPEARS THAT THE GFS AND ECMWF WERE PRETTY CLOSE...THOUGH GFS WAS A BIT FURTHER N WITH THE HEAVIEST PRECIP ON THE 00Z RUN. THE 06Z NAM HAS SHIFTED A BIT FURTHER S THAN ITS 00Z RUN AS WELL AS THE 06Z GFS...MORE IN LINE WITH CURRENT THINKING. THIS...ALONG WITH THE POSITION ON THE 00Z ECMWF...GAVE MORE CONFIDENCE TO LEAN TOWARD THE HIGHEST PRECIP ACROSS SOUTHERN AREAS THROUGH THE DAY TODAY. COLD AIR HAS BEEN FILTERING INTO THE REGION...AS WELL AS DIVING PARTIAL THICKNESSES...SO NO QUESTION THAT THE BULK OF THE PRECIP WILL BE IN THE FORM OF SNOW. ALSO NOTED VERY GOOD DENDRITIC GROWTH REGION AROUND 15Z-20Z ACROSS THE REGION. WITH POSITIVELY TILTED UPPER TROUGH MOVING THROUGH THE MEAN TROUGH POSITION ACROSS THE EASTERN U.S...PRECIP WILL MOVE THROUGH RATHER QUICKLY. LOOKS LIKE SNOW WILL BE OVER BY ABOUT THE START OF THIS EVENING/S COMMUTE. AGREED WITH WPC/S PLACEMENT OF THE HIGHEST QPF AND SNOWFALL ACROSS N CT/RI AND SE MA...MAINLY ON A LINE FROM NEAR HARTFORD THROUGH WILLIMANTIC...PROVIDENCE TO PLYMOUTH SOUTHWARD. SOME QUESTION AS TO SNOW/WATER RATIOS ACROSS CAPE COD AND THE ISLANDS AS TEMPS START OFF IN THE UPPER 30S...BUT SOME AREAS SHOULD SEE ADVISORY LEVEL SNOWS. MELTED PRECIP EXPECTED ON ORDER OF 0.15 TO 0.4 INCHES AND...WITH SOME MODERATE SNOW AT TIMES WHICH WILL BRING THE COLDER AIR DOWN...FELT THAT THERE WILL BE A GOOD AREA OF 2-4 INCHES OF SNOWFALL ACROSS SOUTHERN AREAS. BIG QUESTION AT THIS POINT WILL BE WHETHER BANDING WILL DEVELOP CLOSE ENOUGH TO THE COAST TO BRING HEAVIER SNOWS. AT THIS POINT...THINK THIS WILL STAY JUST OFFSHORE...BUT SOMETHING TO BE CLOSELY MONITORED. SHOULD SEE A PRETTY SHARP LINE OF HEAVIER SNOWFALL...BUT COULD SEE SOME LIGHT SNOWS INTO NORTHERN MA AND POSSIBLY INTO S NH. KEPT ONLY CHANCE POPS GOING N OF THE MASS PIKE. WITH QUICK MOVING NATURE OF THIS SYSTEM...PRECIP WILL TAPER OFF RATHER QUICKLY OVER N CT LATER THIS AFTERNOON...BUT MAY LINGER A BIT ACROSS RI/SE MA INTO THE EVENING COMMUTE. DAYTIME HIGHS WILL GENERALLY BE IN THE 30S...THOUGH TEMPS WILL START TO FALL BY MIDDAY ACROSS THE SNOW AREAS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... TONIGHT... EXPECT PRECIP TO TAPER OFF ACROSS THE REGION BY 01Z-02Z...THEN VERY COLD AIR WORKS INTO THE REGION. EXPECT VERY GOOD MIXING WITH H85 TEMPS DROPPING TO -12C TO -14C OVERNIGHT...SO EXPECT W-NW WINDS TO PICK UP NEAR THE COAST AROUND OR AFTER MIDNIGHT. HIGHEST GUSTS WILL BE OVER THE OUTER CAPE AND NANTUCKET. SKIES WILL BECOME MAINLY CLEAR AS TEMPS DROP TO THE MID TEENS WELL INLAND TO THE 20S ALONG THE IMMEDIATE COAST. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... HIGHLIGHTS... * ARCTIC AIR THU AND FRI * POTENTIAL WINTRY PRECIPITATION SAT/SUN WILL BE BRIEF HERE GIVEN THE EXPECTED ACTIVE WINTER WEATHER TODAY. 00Z GEFS AND ECENS ENSEMBLES ARE IN VERY GOOD AGREEMENT ON THE LARGE SCALE FLOW ALONG WITH THE TIMING AND SMALLER SCALE DETAILS. AN ACTIVE PATTERN CONTINUES THIS PERIOD WITH AN ARCTIC FRONTAL PASSAGE WED NGT OR EARLY THU. BOTH ENSEMBLE DATA SETS /GEFS AND ECENS/ SUPPORT -20C AIRMASS /-2 STD FROM CLIMO/ MOVING ACROSS SOUTHERN NH AND NORTHERN MA THU! THIS WILL LIKELY BE THE COLDEST AIRMASS OF THIS EARLY WINTER SEASON SO FAR. THIS COLD DRY AIRMASS LINGERS INTO FRI AS WELL. HIGHS THU AND FRI WILL ONLY REACH INTO THE 20S! NORMAL HIGH THIS TIME OF YEAR IS IN THE U30S TO L40S. THEN THIS WEEKEND ENSEMBLES REMAIN IN VERY GOOD AGREEMENT WITH SOUTHERN STREAM SYSTEM EXITING THE GULF STATES AND TRACKING NORTHEAST TO THE MID ATLC LATE SAT. COLD AIRMASS LINGERS OVER NEW ENGLAND SAT WHICH WILL SUPPORT PTYPE ISSUES FOR THE REGION. BY 12Z SUNDAY BOTH THE 00Z GEFS AND 12Z ECENS SUPPORT A COASTAL HUGGER WITH LOW PRES TRACKING ALONG OR NEAR THE SOUTHERN NEW ENGLAND COAST. AT THIS EARLY STAGE THIS SCENARIO WOULD SUGGEST A WINTRY MIX TO RAIN FOR THE COASTAL PLAIN INCLUDING PVD/BOS CORRIDOR. HOWEVER IF THIS STORM TRACK VERIFIES SHALLOW COLD AIR WOULD BE DIFFICULT TO SCOUR OUT ACROSS THE INTERIOR. THUS THERE IS A RISK FOR SIGNIFICANT ACCUMULATION OF A WINTRY MIX WELL INLAND...ESPECIALLY GIVEN THIS SOUTHERN STREAM SYSTEM WILL HAVE PLENTY OF QPF. NEVERTHELESS THIS POTENTIAL EVENT IS STILL 4-5 DAYS AWAY SO ITS WAY TOO EARLY TO NAIL DOWN SPECIFICS. NONETHELESS THE POTENTIAL FOR SIGNIFICANT WINTER STORM THIS WEEKEND EXISTS. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR TERM /THROUGH TONIGHT/... MODERATE CONFIDENCE...THOUGH LOW CONFIDENCE ON EXACT TIMING OF LOWERING CONDITIONS. 7 AM UPDATE... DESPITE MANY RETURNS ON LOCAL RADAR SNOW NOT REACHING THE GROUND AT 7 AM. SNOW AS CLOSE AS EASTERN MA. CURRENT THINKING IS FOR HEAVIEST SNOW TO BE CONFINED TO CT/RI AND SOUTHEAST MA ESPECIALLY THE IMMEDIATE SOUTH COAST. SNOW IS FAST MOVING WITH BACK EDGE OF SNOW OVER CAPE COD AROUND 21Z AND BEGINNING TO MOVE OFFSHORE. LITTLE/MINOR ACCUMULATIONS ALONG AND NORTH OF I-90 INTO BOSTON. EARLIER DISCUSSION BELOW. =============================================================== TODAY...EXPECT SNOW TO MOVE IN QUICKLY AFTER 12Z...WITH VSBYS AT OR BELOW 1SM AND LIFR CIGS IN POCKETS OF SN. EXPECT LOWEST CONDITIONS NEAR AND S OF THE MASS PIKE WITH IFR-VLIFR. ACROSS N MA/S NH...SHOULD SEE MAINLY VFR...THOUGH SOME MVFR-IFR MAY WORK INTO NE MA /CAPE ANN AREA/ AROUND MIDDAY. WIDESPREAD ACCUMS OF 1-3 INCHES WITH LOCALLY HIGHER AMOUNTS ESPECIALLY ALONG THE SOUTH COAST INCLUDING THE CAPE AND ISLANDS. SNOW MOVES EAST INTO EVENING AND TERMINALS GRADUALLY IMPROVE BACK TO VFR. TONIGHT...VFR FOR MOST AREAS. MVFR-IFR CIGS/VSBYS MAY LINGER OVER CAPE COD AND THE ISLANDS THROUGH 03Z-04Z...THEN SHOULD IMPROVE. W-NW WINDS GUSTING TO 25-30 KT ON THE OUTER CAPE AND ISLANDS. KBOS TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT. KBDL TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT. OUTLOOK...WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE. MAINLY VFR THRU THE PERIOD. ONLY CAVEAT WILL BE THE POSSIBILITY OF LOCALIZED MVFR CONDITIONS IN SOME OCEAN EFFECTS -SHSN/SHRA FOR CAPE/ISLAND TERMINALS WITH THE BEST CHANCES WED NIGHT AND THU. STRONG NW WIND GUSTS ALSO POSSIBLE WED INTO WED NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE. TODAY...EXPECT LIGHT W-NW WINDS EARLY...WITH GUSTS INCREASING TO AROUND 20 KT THIS AFTERNOON. SNOW WILL MOVE IN FROM W-E WITH REDUCED VSBYS DOWN TO 1/2 MILE OR LESS. SEAS AROUND 5 FT ON THE EASTERN OUTER WATERS EARLY EXPECTED TO SUBSIDE BY MIDDAY. TONIGHT...SNOW WILL END EARLY THIS EVENING...BY AROUND 03Z ON THE EASTERN OUTER WATERS. W-NW WINDS WILL INCREASE AS COLDER AIR WORKS ACROSS THE WATERS...WITH GUSTS TO GALE FORCE FOR A TIME OVERNIGHT ON THE OUTER WATERS. GALE WARNINGS UP THERE...WITH SMALL CRAFTS FOR THE REMAINING WATERS. SEAS WILL ALSO BUILD...UP TO 6-8 FT ON THE OUTER WATERS LATE. OUTLOOK...WEDNESDAY THROUGH FRIDAY...HIGH CONFIDENCE. A PROLONGED PERIOD OF WNW WINDS 25 KT OR HIGHER THROUGH THE PERIOD APPEARS LIKELY. THERE IS ALSO THE LOW PROBABILITY THAT OCCASIONAL GALE FORCE WIND GUSTS OCCUR THU BEHIND ARCTIC FRONTAL PASSAGE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR CTZ002>004. MA...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MAZ017>024. NH...NONE. RI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR RIZ001>008. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR ANZ231>235-237. SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 2 AM EST WEDNESDAY FOR ANZ230-236. GALE WARNING FROM 9 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR ANZ250-254>256. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR ANZ251. && $$ SYNOPSIS...NOCERA/EVT NEAR TERM...EVT SHORT TERM...EVT LONG TERM...NOCERA AVIATION...NOCERA/EVT MARINE...NOCERA/EVT
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
632 AM EST TUE DEC 10 2013 .PREV DISCUSSION... /ISSUED 358 AM EST TUE DEC 10 2013/ SHORT TERM /TODAY THROUGH WEDNESDAY/... SHORT TERM MODELS ARE IN GOOD AGREEMENT FOR THE MOST PART ALTHOUGH SOME DISCREPANCIES NOTED...NAM/SREF FASTER AND GFS/ECMWF SLOWER TO PUSH FRONT THROUGH FORECAST AREA TODAY. RAP HAS INITIALIZED WELL AND IS HANDLING THE RAIN BAND OVER NORTHWEST GEORGIA FAIRLY WELL AND IS IN LINE WITH FASTER SOLUTIONS. TEMPERATURES REMAIN IN THE LOWER 40S ACROSS NORTHWEST GEORGIA AND WITH SLOW PROGRESS OF COLDER AIR TO THE NORTH DO NOT EXPECT WINTRY PRECIP IN THE FORECAST AREA. COLDER AIR WILL FILTER INTO PORTIONS OF NORTH GEORGIA BY MID-LATE MORNING...AND MODELS ARE TRYING TO SCATTER/CLEAR SKIES RAPIDLY BEHIND THE FRONT. THIS WILL RESULT IN MAXIMUM TEMPERATURES ACROSS NORTH GEORGIA...INCLUDING THE ATLANTA METRO AREA...THIS MORNING. COLD AIR ADVECTION BEHIND THE FRONT IS NOT IMPRESSIVE...BUT SHOULD BE ENOUGH TO OFFSET ANY HEATING BY THE SCATTERING CLOUDS WHICH WILL RESULT IN SEVERAL HOURS OF NEAR STEADY TEMPERATURES ACROSS NORTH GEORGIA. 1000-850 WINDS WILL INCREASE BEHIND THE FRONT WITH GUSTS OF 25-30MPH EXPECTED BY LATE MORNING IN NORTH GEORGIA...SPREADING SOUTHWARD INTO CENTRAL GEORGIA BY EARLY AFTERNOON AND CONTINUING THROUGH EARLY THIS EVENING. DRIER AIR FILTERING INTO THE FORECAST AREA BY TONIGHT...BUT WIND SPEEDS WILL REMAIN IN THE 5-10MPH RANGE OVERNIGHT WHICH WILL KEEP TEMPERATURES FROM RADIATING OUT AS MUCH AS THEY COULD...HOWEVER TEMPERATURES WILL DROP TO LOWER TO MID 20S NORTH GEORGIA AND IN THE MID 30S OVER CENTRAL GEORGIA BY MORNING. TEMPERATURES WILL MODERATE ON WEDNESDAY TO NEAR NORMAL AS DRY WEATHER AND MOSTLY CLEAR SKIES SET UP ACROSS THE AREA. ATWELL LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... EXTENDED BEGINS WITH LONGWAVE TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...WITH ANOTHER SHORTWAVE DIVING THROUGH THE CENTRAL PLAINS. THIS DRY WAVE WILL PUSH INTO THE SOUTHEAST THURSDAY MORNING BUT WILL BRING A REINFORCING SHOT OF COOL AIR TO THE REGION. WEAK RIDGING BUILDS IN ALOFT FRIDAY AHEAD OF A STRONG SYSTEM OVER THE DESERT SOUTHWEST. SURFACE LOW WILL PUSH INTO THE SOUTHERN PLAINS FRIDAY NIGHT...WITH STRONG SOUTHERLIES PUMPING GULF MOISTURE BACK INTO THE SOUTHEAST. PRECIP OVERSPREADS THE AREA FRIDAY NIGHT AND ESPECIALLY SATURDAY...AND GIVEN AGREEMENT BETWEEN GFS AND ECMWF AS WELL AS RUN-TO-RUN CONSISTENCY...HAVE INCREASED POPS TO CATEGORICAL ON SATURDAY. LOOKS LIKE EASILY ANOTHER INCH OF RAIN ACROSS THE AREA. THERE MAY BE ENOUGH INSTABILITY CREEPING INTO SOUTHERN ZONES SATURDAY AFTERNOON TO WARRANT ADDING THUNDER TO THE FORECAST...BUT HAVE LEFT IT OUT FOR NOW. COMPLICATING FACTOR IS DIABATICALLY ENHANCED CLASSICAL CAD DEVELOPING FRIDAY NIGHT AND EARLY SATURDAY...THOUGH RIGHT NOW THICKNESSES ACROSS GEORGIA FOR THE MOST PART LOOK TOO WARM FOR ANY WINTRY PRECIP...BUT LATER FORECASTS WILL HAVE TO BE REEVALUATED. DID ADD A BRIEF RAIN/SNOW MIX EXTREME NORTH SUNDAY MORNING AS THE COLD FRONT PUSHES THROUGH. GFS IS JUST A TAD FASTER THAN THE ECMWF BY THIS POINT SO UNCERTAINTY IS INCREASING. COOL AND WINDY BEHIND THE FRONT BUT CLEARING INTO EARLY NEXT WEEK. TDP AVIATION... 06Z UPDATE... IFR TO MVFR CONDITIONS WILL DETERIORATE TO IFR...SOME LIFR AT TAF SITES. LIGHT RAIN MOVING ACROSS TAF SITES MAINLY THIS MORNING WILL AID IN IMPROVING CIGS TO MVFR. COLDER AIR FILTERING IN MAY STALL CLEARING SKIES BUT WILL GO VFR AFTER 18-20Z. WINDS WILL INCREASE OUT OF NW 10-15KTS WITH GUSTS TO 27KTS EXPECTED. //ATL CONFIDENCE...06Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. ATWELL && .AVIATION... 12Z UPDATE... IMPROVING TRENDS EXPECTED TODAY. LIGHT RAIN ASSOCIATED WITH THE COLDFRONT WILL WORK ITS WAY ACROSS THE TAF SITES 15-17Z. CIGS WILL IMPROVE TO MVFR/VFR AFTER 17Z. NORTHWEST WINDS WILL INCREASE TO 15-20KTS WITH GUSTS TO 27 THROUGH THIS AFTERNOON. WINDS WILL SHIFT OUT OF THE NORTHEAST AND BECOME LIGHT DURING THE OVERNIGHT HOURS. //ATL CONFIDENCE...12Z UPDATE... MEDIUM CONFIDENCE IN CIGS. MEDIUM TO HIGH CONFIDENCE IN ALL OTHER ELEMENTS. ATWELL && .PRELIMINARY POINT TEMPS/POPS... ATHENS 53 28 55 29 / 80 0 5 5 ATLANTA 50 30 55 31 / 80 0 5 5 BLAIRSVILLE 47 22 52 23 / 60 0 5 5 CARTERSVILLE 48 24 53 26 / 70 0 5 5 COLUMBUS 59 32 59 36 / 50 0 5 5 GAINESVILLE 50 29 53 31 / 80 0 5 5 MACON 61 28 58 30 / 60 0 5 5 ROME 47 22 52 25 / 50 0 5 5 PEACHTREE CITY 49 25 55 28 / 80 0 5 5 VIDALIA 69 39 59 40 / 50 5 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ATWELL LONG TERM....TDP AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
959 AM CST TUE DEC 10 2013 .DISCUSSION... 947 AM CST FOR MORNING UPDATE... ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH. MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN. A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL... WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA. OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING FORECAST. RATZER //PREV DISCUSSION... 329 AM CST CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS. FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND. TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS. NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE 270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE. FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT. RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET. STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF 10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE. SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION. MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * WESTERLY WINDS GUSTING IN EXCESS OF 30 KT THROUGH THIS AFTERNOON. * BETTER CHANCES FOR SNOW LATE TONIGHT INTO EARLY WEDNESDAY WHICH IS EXPECTED TO PRODUCE 2 TO 3 INCHES OF SNOW ACCUMULATION. BMD/KB //DISCUSSION...UPDATED 12Z... A PAIR OF CLIPPERS WILL RACE ACROSS THE AREA IN THE UPCOMING TAF PERIOD. THE FIRST SYSTEM IS ALREADY PUSHING EAST ACROSS WISCONSIN WITH A FEW PATCHES OF SNOW DEVELOPING AS FAR SOUTH AS EASTERN IOWA EARLY THIS MORNING. THIS AREA OF SNOW WILL BE THE MAIN CONCERN THIS MORNING AS IT WILL TRACK NEAR THE TERMINALS. HAVE INCLUDED TEMPO FOR SNOW AT RFD...BUT NAM/RAP GUIDANCE WHICH SEEM TO BE INITIALIZING BEST ON THIS AREA OF SNOW BOTH SUGGEST IT WILL LIFT NORTH OF THE CHICAGO AREA TERMINALS WHILE DISSIPATING LATER THIS MORNING. IF ON THE OFF CHANCE IT WERE TO IMPACT THE TERMINALS...WOULD EXPECT VSBY TO DROP ANYWHERE FROM 1/2SM TO 2SM FOR ABOUT AN HOUR. WINDS WILL BE VEERING BACK TO THE WEST BY EARLY AFTERNOON...WITH GUSTS IN EXCESS OF 30 KTS EXPECTED. A BRIEF LULL IN THE WINDS IS EXPECTED AFTER SUNSET AS A WEAK RIDGE BUILDS OVER THE AREA. MEANWHILE...THE NEXT CLIPPER SYSTEM WILL BE TAKING AIM AT THE AREA...DROPPING SOUTHEAST ACROSS NORTHERN IOWA AND MOVING INTO NORTH CENTRAL ILLINOIS AROUND MIDNIGHT CST TONIGHT. VSBY WILL LIKELY DROP TO IFR WITH VSBY LESS THAN 1SM A DISTINCT POSSIBILITY. EXPECT TWO TO THREE INCHES OF SNOW TO ACCUMULATE. BMD //ORD AND MDW CONFIDENCE...UPDATED 16Z... * MEDIUM-HIGH CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN CIG TRENDS. * MEDIUM-HIGH CONFIDENCE IN SNOW LATE TONIGHT INTO EARLY WEDNESDAY WITH IFR VSBY. BMD/KB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL. SATURDAY...SNOW LIKELY. IFR. SUNDAY...CHC SNOW. IMPROVING TO VFR. MONDAY...VFR. BMD && .MARINE... 324 AM CST TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013- ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
948 AM CST TUE DEC 10 2013 .DISCUSSION... 947 AM CST FOR MORNING UPDATE... ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH. MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN. A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL... WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA. OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING FORECAST. RATZER && .PREV DISCUSSION... 329 AM CST CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS. FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND. TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS. NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE 270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE. FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT. RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET. STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF 10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE. SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION. MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * BRIEF PERIOD OF -SHSN THIS MORNING BETWEEN 14 AND 16 UTC WITH VSBY OF 1 TO 2 SM. * WESTERLY WINDS GUSTING IN EXCESS OF 30 KT LATE THIS MORNING THROUGH THIS AFTERNOON. * BETTER CHANCES FOR SNOW LATE TONIGHT INTO EARLY WEDNESDAY WHICH IS EXPECTED TO PRODUCE 2 TO 3 INCHES OF SNOW ACCUMULATION. BMD/KB //DISCUSSION...UPDATED 12Z... A PAIR OF CLIPPERS WILL RACE ACROSS THE AREA IN THE UPCOMING TAF PERIOD. THE FIRST SYSTEM IS ALREADY PUSHING EAST ACROSS WISCONSIN WITH A FEW PATCHES OF SNOW DEVELOPING AS FAR SOUTH AS EASTERN IOWA EARLY THIS MORNING. THIS AREA OF SNOW WILL BE THE MAIN CONCERN THIS MORNING AS IT WILL TRACK NEAR THE TERMINALS. HAVE INCLUDED TEMPO FOR SNOW AT RFD...BUT NAM/RAP GUIDANCE WHICH SEEM TO BE INITIALIZING BEST ON THIS AREA OF SNOW BOTH SUGGEST IT WILL LIFT NORTH OF THE CHICAGO AREA TERMINALS WHILE DISSIPATING LATER THIS MORNING. IF ON THE OFF CHANCE IT WERE TO IMPACT THE TERMINALS...WOULD EXPECT VSBY TO DROP ANYWHERE FROM 1/2SM TO 2SM FOR ABOUT AN HOUR. WINDS WILL BE VEERING BACK TO THE WEST BY EARLY AFTERNOON...WITH GUSTS IN EXCESS OF 30 KTS EXPECTED. A BRIEF LULL IN THE WINDS IS EXPECTED AFTER SUNSET AS A WEAK RIDGE BUILDS OVER THE AREA. MEANWHILE...THE NEXT CLIPPER SYSTEM WILL BE TAKING AIM AT THE AREA...DROPPING SOUTHEAST ACROSS NORTHERN IOWA AND MOVING INTO NORTH CENTRAL ILLINOIS AROUND MIDNIGHT CST TONIGHT. VSBY WILL LIKELY DROP TO IFR WITH VSBY LESS THAN 1SM A DISTINCT POSSIBILITY. EXPECT TWO TO THREE INCHES OF SNOW TO ACCUMULATE. BMD //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN SNOW IMPACTING TERMINALS THIS MORNING WITH 1 TO 2 SM VIS FOR A SHORT PERIOD THROUGH 16 UTC. * MEDIUM-HIGH CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN CIG TRENDS. * MEDIUM-HIGH CONFIDENCE IN SNOW LATE TONIGHT INTO EARLY WEDNESDAY WITH IFR VSBY. BMD/KB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL. SATURDAY...SNOW LIKELY. IFR. SUNDAY...CHC SNOW. IMPROVING TO VFR. MONDAY...VFR. BMD && .MARINE... 324 AM CST TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013- ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
605 AM CST TUE DEC 10 2013 ...UPDATED AVIATION DISCUSSION... .SHORT TERM /TODAY/... ISSUED AT 353 AM CST TUE DEC 10 2013 MAIN FORECAST CONCERN TODAY IS WITH STRONG WINDS AND LIGHT SNOW POTENTIAL EARLY THIS MORNING AND ADDITIONAL SNOW CHANCES LATE THIS AFTERNOON. LEANED TOWARD A BLEND OF THE HOPWRF/NAM12/RAP THROUGH MIDDAY TODAY...AND THEN NAM12/RAP THIS AFTERNOON. QUICK MOVING SHORTWAVE AND STRONG PV ANOMALY WILL CONTINUE TO INCREASE WINDS THIS MORNING AND PROVIDE A BLOWING SNOW POTENTIAL TO NORTHERN IOWA. LIGHT SNOW IS POSSIBLE THROUGH 12Z/13Z TIME AS SOUNDINGS LOSE ICE INTRODUCTION AND DEEP MOISTURE OVER THE FAR NORTH LATER THIS MORNING. WINDS ATOP THE MIXED LAYER NEAR 40 KNOTS AT MCW AND LIKELY WILL SEE BLSN DUE TO THE FRESH SNOW PACK THROUGH MIDDAY. WINDS DIMINISH SLIGHTLY THIS AFTERNOON AS PRESSURE GRADIENT DECREASES. SHORTWAVE QUICKLY DEPARTS THE STATE BY 15Z AND SHOULD SEE SOME CLEARING LATE THIS MORNING INTO THE EARLY AFTERNOON WITH DRY AIR ADVECTING INTO THE STATE. NEXT SHORTWAVE LOOKS TO FOLLOW A SIMILAR TRACK AND AFFECT NORTHERN IOWA...BUT DIFFERENCE WITH THIS SYSTEM IT HAS MORE MOISTURE AND FORCING. POPS INCREASE RAPIDLY PAST 21Z TODAY ACROSS THE NORTH AS NAM AND RAP CONSISTENT ON BRINGING THIS SHORTWAVE INTO THE REGION A BIT QUICKER. TEMPERATURE TREND TODAY WILL BE TRICKY AS WAA CONTINUES AHEAD OF THE TROUGH AND KEEPS THEM STEADY OR SLOWLY RISING BEFORE CAA TAKES OVER BRIEFLY LATE THIS MORNING. THEN MIXING AND SUNSHINE DOMINATE THIS AFTERNOON WARMING TEMPS AGAIN. .LONG TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 353 AM CST TUE DEC 10 2013 THE PRIMARY FORECAST CONCERN WILL BE EARLY IN THE PERIOD. NEXT SYSTEM WILL ALREADY BE ENTERING NORTHWEST IOWA BY 00Z THIS EVENING WITH A BAND OF SNOW DEVELOPING. THIS BAND OF SNOW WILL BE FOCUSED OVER THE NORTHERN HALF OF THE FORECAST AREA THOUGH SOME LIGHT SNOW MAY FAR ACROSS THE SOUTH AS WELL. THOUGH NOT AS IMPRESSIVE AS SUNDAY...A RELATIVELY GOOD LOW LEVEL DENDRITIC LAYER DEPTH OF AROUND 8 KFT. WHILE FORCING WILL BE SPREAD THROUGHOUT A DEEP LAYER AND WILL RESULT IN AN ARRAY OF FLAKE TYPES...THERE WILL BE A PERIOD OF HIGH SNOW RATIO DENDRITES. WITH LIQUID EQUIVALENT VALUES OF GENERALLY ONE TENTH INCH OR LESS WILL RESULT IN SNOWFALL OF 1 TO 2 INCHES ACROSS THE NORTH WITH A MAX CEILING OF 3 INCHES. A STRONG COLD FRONT WILL SWEEP IN IMMEDIATELY BEHIND THE SNOW AND WILL BRING ANOTHER ARCTIC SURGE AND GUSTY NORTHWEST WINDS BACK TO THE STATE. THE COLD AIR AND INCREASING WINDS WILL PRESENT A COUPLE ISSUES. THE MOST OBVIOUS WILL BE EXPECTED BITTERLY COLD WIND CHILLS OF -20 TO -30 ACROSS FAR NORTHERN PORTIONS LATE TONIGHT AND THROUGH MUCH OF WEDNESDAY MORNING. THE SECOND IS THE STRENGTH OF WINDS AND THE IMPACT ON THE NEWLY FALLEN FLUFFY SNOW AND WHAT WAS ON THE GROUND FROM SUNDAY. HIGHLY EFFICIENT MOMENTUM TRANSFER OF MIXED LAYER WINDS WILL BE PRESENT DUE TO THE STRONG COLD ADVECTION. THIS COMBINED WITH A PERIOD OF GOOD PRESSURE GRADIENT WITH A STRONG PRESSURE RISE COUPLET WILL LEAD TO STRONGER WINDS THAN MODELS CURRENTLY SUGGEST. THESE CONDITIONS SHOULD LEAD TO A PERIOD OF LOW LEVEL BLOWING SNOW WHICH MAY NOT SIGNIFICANTLY REDUCE VISIBILITIES BUT WILL LEAD TO DETERIORATED ROAD CONDITIONS. THE SNOW AND BLOWING SNOW LIKELY WILL NOT MEET WINTER WEATHER ADVISORY CRITERIA ALONG. HOWEVER...THIS LEADS TO A HEADLINE DECISION QUANDARY. WITH A GOOD CERTAINTY ON THE WIND CHILL CRITERIA BEING MET...THE BEST OPTION MAY BE TO PACKAGE EVERYTHING TOGETHER INTO A WINTER WEATHER ADVISORY. WITH IT BEING SECOND PERIOD...WILL ALLOW THE DAY SHIFT ANOTHER LOOK AS THE SYSTEM NEARS. ARCTIC COLD TEMPERATURES CAN BE EXPECTED FOR WEDNESDAY FOLLOWED BY A QUICK DROP IN THE EVENING A HIGH PRESSURE SLIDES THROUGH WITH WARM ADVECTION AND RISING TEMPERATURES AFTER MIDNIGHT. WARMER BUT SEASONABLY COLD FOR THURSDAY. ANOTHER COLD FRONT PASSES THROUGH ON FRIDAY. THERE IS POTENTIAL FOR THE STATE TO BE IMPACTED BY LIGHT SNOW WITH THE BOUNDARY ARRIVING FROM THE NORTH. ALSO MOISTURE STREAMING NORTH FROM THE GULF MAY REACH SOUTHEAST IOWA. THIS PRECIPITATION COULD FOR A WINTRY MIX WITH A WARM NOSE ALOFT NUDGING IN BEFORE THE BOUNDARY PUSHES IT SOUTH AGAIN. SIGNS POINTING TO ANOTHER ARCTIC BLAST AROUND SUNDAY TO END THE PERIOD QUITE COLD. && .AVIATION...10/12Z ISSUED AT 605 AM CST TUE DEC 10 2013 AREAS OF BLSN WILL CONTINUE TO CAUSE MVFR/IFR VIS THROUGH 14/15Z THIS MORNING AT ALO/MCW. OTHERWISE...STRONG WINDS WILL CONTINUE THROUGH MUCH OF THE MORNING HOURS BEFORE DIMINISHING THIS AFTERNOON. THE SECOND SHORTWAVE WILL BRING SNOW CHANCES THIS EVENING AND HAVE MENTION OF MVFR CIGS/VIS THIS EVENING AND THEN MVFR VIS/CIGS DUE TO BLSN OVERNIGHT INTO WED FOR ALO/MCW/FOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
853 AM EST TUE DEC 10 2013 .SYNOPSIS... A POTENT UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION TODAY. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH THE END OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING FOR PORTIONS OF WESTERN MARYLAND...THE NORTHERN SHENANDOAH VALLEY OF VIRGINIA AND THE EASTERN WEST VIRGINIA PANHANDLE. THERE HAVE BEEN REPORTS OF 3 TO 5 INCHES OF SNOW. THE HEAVIEST SNOW HAS DISSIPATED...BUT AN ADDITIONAL INCH OR TWO OF SNOW IS EXPECTED THROUGH EARLY AFTERNOON. THE PREVIOUS DISCUSSION FOLLOWS... LTST SFC ANALY DEPICT LOPRES IN WRN VA/NC. LOW A SFC REFLECTION OF VORTMAX/RRQ OF 180 KT UPR JET. ASSOCD PCPN HAS RAPIDLY BEEN FILLING IN ACRS THE OH/TN VLYS...AND IS ON THE WRN DOORSTEP ATTM. GDNC IN GOOD AGREEMENT THAT THIS WL BE TRACKING ACRS CWFA...PRIMARILY BTWN 12-18 UTC. THE ARRIVAL OF THIS PCPN WL PROVIDE ENUF MIXING TO ERODE FOG CURRENTLY IN PLACE. A STRIP OF DENSE FOG RESIDES FM CHO-IAD. TRENDS SINCE 04Z INDICATE A SLOW IMPRVMNT HAS BEGUN...AND HV ALLWD DENSE FOG ADVY TO EXPIRE AT 08Z. AFTER THAT...VSBY STILL WONT BE GREAT...AS FOG RESTRICTIONS WL BE REPLACED W/ SNOW RESTRICTIONS. THE FEATURES RESPONSIBLE FOR THE SNOW LOOK TO BE PROGRESSIVE. BUT...LIFT VIGOROUS AND H7-5 F-VECTORS DO POINT TO MESOSCALE BANDING. WHILE MAX LIFT NOT EXACTLY IN DENTRITIC GROWTH ZONE...A THIRD TO HALF INCH LIQ QPF SUGGESTS THAT WRNG CRITERIA THREATENED. CANNOT PLACE EXACTLY WHERE THE BANDS WL SET UP /LTST HRRR AND WRF RUNS SUGGEST CHO-DCA-MTN/...FEEL FAIRLY CONFIDENT THAT LCLLY HIER AMTS PSBL. GFS SUGGESTS THAT THE BAND MAY BE NW OF CURRENT 3-6 INCH FCST STRIPE. CONFIDENCE DIMINISHES TWD EZF AND SRN MD DUE TO LOWER SNW RATIOS AND MDL SNDGS SUGGESTING PL WL MIX IN. BOTH OF THESE FACTORS WL REDUCE SNW TTLS. IN LIGHT OF 00Z GDNC...POTL FOR HIER TTLS...AND NOT CERTAIN BANDS WL BE W/IN PREVIOUS WRNG AREA...HV OPTED TO WIDEN WRNG AREA TO INCL LUA-FDK ON THE NW AND CHO- OMH ON THE SE. TIME FRAME NOT EXTENDED AS GDNC STILL PRETTY INSISTENT THAT SNOW SHUD BE ENDING BY 18Z. MAY EVEN SEE BRIGHTENING SKIES BEFORE SUNSET. ONCE SNOW STARTS...TEMPS CHGG LTL...AND FCST MAXT REFLECTS THAT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... HIPRES BLDS TNGT...WL BE ARND THRU WED NGT. SUBSIDENCE INCREASES RAPIDLY...PROVIDING ONLY A SMALL WINDOW FOR UPSLP SHSN THIS EVNG. OTRW...MOCLR SKIES AND CAA DOMINATE THE PD. TOOK MOS BLEND FOR TEMPS. && .LONG TERM /THURSDAY THROUGH MONDAY/... A LONG WAVE TROUGH SHOULD MOVE OFF THE EAST COAST FRIDAY AS HIGH PRESSURE MOVES TO OUR SOUTH. A SLIGHT RELIEF IN TEMPERATURES IS EXPECTED SATURDAY AS RETURN FLOW BRINGS TEMPS IN THE 40S INTO THE REGION. A COLORADO LOW IS EXPECTED TO FORM MID WEEK AND TRAVEL CLOSE TO THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH THIS TREND AND A WINTRY MIX IS EXPECTED AS IT APPROACHES THE MID ATLANTIC. PTYPE AND TIMING SPECIFICS ARE STILL IN QUESTION. LOW PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... LIFR STILL WIDESPREAD...BUT FOG SHUD BE LIFTING BEFORE DAWN. HWVR...VSBY RESTRICTIONS DUE TO FOG WL BE REPLACED BY RESTRICTIONS DUE TO SNOW. ONSET PRIOR TO 12Z. POOR CONDS WL CONT THRU 18Z. VFR TNGT-FRI UNDER HIPRES. DIMINISHED CIGS/VSBYS PSBL SAT AHD OF THE NEXT SYSTEM TO IMPACT THE RGN. && .MARINE... WNDS BLO 10 KT ATTM. MIXING REMAINS POOR THRU THE DAY. HWVR...AS A DISTURBANCE GLIDES BY...PROVIDING A PD OF SNOW...PERHAPS MIXED W/ PL AND A LTL RA IN THE MID BAY...SOME GDNC SUGGESTING WNDS WL PICK UP. HV NOT FLLWD THAT SOLN ATTM...AND HV CAPPED WNDS AT 15 KT. WL NEED TO MONITOR IN CASE A SCA REQD. IN THE WAKE OF THE LOW...COLD AIR WL STREAM IN...PROVIDING A SETUP FOR MORE FVRBL MIXING. WL KEEP SCA IN PLACE TNGT. WNDS DIMINISH FOR WED UNDER HIPRES...WHICH WL BE ARND THRU FRI. A DISTURBANCE MOVE INTO OVR THE WATERS SAT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR DCZ001. MD...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MDZ016>018-501-502. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR MDZ003>007-009>011-013-014. VA...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR VAZ025-026-036>038-050-055>057-503-504. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR VAZ027>031-039-040-042-051>054-501-502. WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR WVZ050-051-055-501>506. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR WVZ052- 053. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR ANZ530>543. && $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...HTS LONG TERM...HAS AVIATION...HTS MARINE...HTS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
810 AM EST TUE DEC 10 2013 .SYNOPSIS... A POTENT UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION TODAY. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH THE END OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ...UPDATE TO DOWNGRADE THE WINTER STORM WARNING TO AN ADVISORY FOR THE CENTRAL SHENANDOAH VALLEY INTO CENTRAL VIRGINIA. ELSEWHERE...THE WINTER WEATHER HEADLINES HAVE NOT CHANGED. THE HEAVIEST IS EXPECTED TO BE NEAR AND EAST OF THE BLUE RIDGE MOUNTAINS DURING THE MID TO LATE MORNING HOURS. THE PREVIOUS DISCUSSION FOLLOWS... LTST SFC ANALY DEPICT LOPRES IN WRN VA/NC. LOW A SFC REFLECTION OF VORTMAX/RRQ OF 180 KT UPR JET. ASSOCD PCPN HAS RAPIDLY BEEN FILLING IN ACRS THE OH/TN VLYS...AND IS ON THE WRN DOORSTEP ATTM. GDNC IN GOOD AGREEMENT THAT THIS WL BE TRACKING ACRS CWFA...PRIMARILY BTWN 12-18 UTC. THE ARRIVAL OF THIS PCPN WL PROVIDE ENUF MIXING TO ERODE FOG CURRENTLY IN PLACE. A STRIP OF DENSE FOG RESIDES FM CHO-IAD. TRENDS SINCE 04Z INDICATE A SLOW IMPRVMNT HAS BEGUN...AND HV ALLWD DENSE FOG ADVY TO EXPIRE AT 08Z. AFTER THAT...VSBY STILL WONT BE GREAT...AS FOG RESTRICTIONS WL BE REPLACED W/ SNOW RESTRICTIONS. THE FEATURES RESPONSIBLE FOR THE SNOW LOOK TO BE PROGRESSIVE. BUT...LIFT VIGOROUS AND H7-5 F-VECTORS DO POINT TO MESOSCALE BANDING. WHILE MAX LIFT NOT EXACTLY IN DENTRITIC GROWTH ZONE...A THIRD TO HALF INCH LIQ QPF SUGGESTS THAT WRNG CRITERIA THREATENED. CANNOT PLACE EXACTLY WHERE THE BANDS WL SET UP /LTST HRRR AND WRF RUNS SUGGEST CHO-DCA-MTN/...FEEL FAIRLY CONFIDENT THAT LCLLY HIER AMTS PSBL. GFS SUGGESTS THAT THE BAND MAY BE NW OF CURRENT 3-6 INCH FCST STRIPE. CONFIDENCE DIMINISHES TWD EZF AND SRN MD DUE TO LOWER SNW RATIOS AND MDL SNDGS SUGGESTING PL WL MIX IN. BOTH OF THESE FACTORS WL REDUCE SNW TTLS. IN LIGHT OF 00Z GDNC...POTL FOR HIER TTLS...AND NOT CERTAIN BANDS WL BE W/IN PREVIOUS WRNG AREA...HV OPTED TO WIDEN WRNG AREA TO INCL LUA-FDK ON THE NW AND CHO- OMH ON THE SE. TIME FRAME NOT EXTENDED AS GDNC STILL PRETTY INSISTENT THAT SNOW SHUD BE ENDING BY 18Z. MAY EVEN SEE BRIGHTENING SKIES BEFORE SUNSET. ONCE SNOW STARTS...TEMPS CHGG LTL...AND FCST MAXT REFLECTS THAT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... HIPRES BLDS TNGT...WL BE ARND THRU WED NGT. SUBSIDENCE INCREASES RAPIDLY...PROVIDING ONLY A SMALL WINDOW FOR UPSLP SHSN THIS EVNG. OTRW...MOCLR SKIES AND CAA DOMINATE THE PD. TOOK MOS BLEND FOR TEMPS. && .LONG TERM /THURSDAY THROUGH MONDAY/... A LONG WAVE TROUGH SHOULD MOVE OFF THE EAST COAST FRIDAY AS HIGH PRESSURE MOVES TO OUR SOUTH. A SLIGHT RELIEF IN TEMPERATURES IS EXPECTED SATURDAY AS RETURN FLOW BRINGS TEMPS IN THE 40S INTO THE REGION. A COLORADO LOW IS EXPECTED TO FORM MID WEEK AND TRAVEL CLOSE TO THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH THIS TREND AND A WINTRY MIX IS EXPECTED AS IT APPROACHES THE MID ATLANTIC. PTYPE AND TIMING SPECIFICS ARE STILL IN QUESTION. LOW PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... LIFR STILL WIDESPREAD...BUT FOG SHUD BE LIFTING BEFORE DAWN. HWVR...VSBY RESTRICTIONS DUE TO FOG WL BE REPLACED BY RESTRICTIONS DUE TO SNOW. ONSET PRIOR TO 12Z. POOR CONDS WL CONT THRU 18Z. VFR TNGT-FRI UNDER HIPRES. DIMINISHED CIGS/VSBYS PSBL SAT AHD OF THE NEXT SYSTEM TO IMPACT THE RGN. && .MARINE... WNDS BLO 10 KT ATTM. MIXING REMAINS POOR THRU THE DAY. HWVR...AS A DISTURBANCE GLIDES BY...PROVIDING A PD OF SNOW...PERHAPS MIXED W/ PL AND A LTL RA IN THE MID BAY...SOME GDNC SUGGESTING WNDS WL PICK UP. HV NOT FLLWD THAT SOLN ATTM...AND HV CAPPED WNDS AT 15 KT. WL NEED TO MONITOR IN CASE A SCA REQD. IN THE WAKE OF THE LOW...COLD AIR WL STREAM IN...PROVIDING A SETUP FOR MORE FVRBL MIXING. WL KEEP SCA IN PLACE TNGT. WNDS DIMINISH FOR WED UNDER HIPRES...WHICH WL BE ARND THRU FRI. A DISTURBANCE MOVE INTO OVR THE WATERS SAT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR DCZ001. MD...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MDZ003-016>018-501-502. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR MDZ004>007-009>011-013-014. VA...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR VAZ025-026-028-036>038-050-055>057-503-504. WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR VAZ027- 029>031-039-040-042-051>054-501-502. WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR WVZ050>053-055-501>506. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR ANZ530>543. && $$ SYNOPSIS...HTS NEAR TERM...HTS/BJL SHORT TERM...HTS LONG TERM...HAS AVIATION...HTS MARINE...HTS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
708 AM EST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 557 AM EST TUE DEC 10 2013 MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE AREAS. WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW OUT OVER LAKE SUPERIOR EARLY THIS MORNING. TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION (LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE. WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST 2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND -25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY. WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY AND A LES WARNING FOR LUCE COUNTY. WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR -10F. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 534 AM EST TUE DEC 10 2013 CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE WEEKEND. WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL TONIGHT. THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE. INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES INTENSITY GREATLY WEDNESDAY EVENING. A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA. HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING. MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES WILL NOT BE OUT OF THE QUESTION QUITE YET. THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE ENOUGH TO DISRUPT REMAINING LES. FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A DUSTING OF SNOW. MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 642 AM EST TUE DEC 10 2013 KIWD...LIGHT SNOW MOVING THROUGH THIS MORNING WILL PRODUCE BRIEF IFR CONDITIONS. EXPECT CONDITIONS TO IMPROVE TO MVFR LATE THIS MORNING AND AFTERNOON AS WSW FLOW INCREASES AND LIGHT LES BEGINS. MORE FAVORABLE WRLY FLOW DEVELOPING LATE TONIGHT COULD SEND CONDITIONS NEAR IFR AS HEAVIER LES BANDS COULD GLANCE THE TAF SITE. KCMX...VFR CONDITIONS WILL QUICKLY LOWER TO VLIFR BY LATE MORNING AS HEAVY LES AND BLSN MOVES INTO THE AREA. THERE COULD BE SLIGHT IMPROVEMENT TO LIFR CONDITIONS LATE THIS AFTERNOON AND THEN TO IFR THIS EVENING AS WINDS GRADUALLY VEER FROM WEST TO WNW PUSHING HEAVIEST LES BANDS TO THE SOUTH. KSAW...VFR CONDITIONS SHOULD CONTINUE THROUGH MUCH OF THE PERIOD IN A STRENGHENING SW-W FLOW. SOME MVFR CONDITIONS MAY DEVELOP LATE TONIGHT AS WINDS VEER WNW AS SOME LIGHT LES COULD WORK ITS WAY INTO THE AREA. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 557 AM EST TUE DEC 10 2013 AFTER A DECREASE IN SOUTHWEST WINDS THIS MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR AND COULD PRODUCE GALES FOR THE SOUTH CENTRAL LAKE LATE THIS AFTERNOON INTO THIS EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 11 AM THIS MORNING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ002-003. LAKE EFFECT SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST WEDNESDAY FOR MIZ001. LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST WEDNESDAY FOR MIZ004-084. LAKE EFFECT SNOW ADVISORY FROM NOON TODAY TO 11 AM CST WEDNESDAY FOR MIZ009. LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST THURSDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ006. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ245-248>251-265>267. GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR LSZ266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
558 AM EST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 557 AM EST TUE DEC 10 2013 MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE AREAS. WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW OUT OVER LAKE SUPERIOR EARLY THIS MORNING. TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION (LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE. WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST 2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND -25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY. WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY AND A LES WARNING FOR LUCE COUNTY. WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR -10F. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 534 AM EST TUE DEC 10 2013 CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE WEEKEND. WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL TONIGHT. THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE. INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES INTENSITY GREATLY WEDNESDAY EVENING. A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA. HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING. MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES WILL NOT BE OUT OF THE QUESTION QUITE YET. THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE ENOUGH TO DISRUPT REMAINING LES. FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A DUSTING OF SNOW. MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1239 AM EST TUE DEC 10 2013 KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE FROM THE NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST PERIOD. KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AND THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE THROUGH TUE EVENING. KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 557 AM EST TUE DEC 10 2013 AFTER A DECREASE IN SOUTHWEST WINDS THIS MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR AND COULD PRODUCE GALES FOR THE SOUTH CENTRAL LAKE LATE THIS AFTERNOON INTO THIS EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 11 AM THIS MORNING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ002-003. LAKE EFFECT SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST WEDNESDAY FOR MIZ001. LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST WEDNESDAY FOR MIZ004-084. LAKE EFFECT SNOW ADVISORY FROM NOON TODAY TO 11 AM CST WEDNESDAY FOR MIZ009. LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST THURSDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ006. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ245-248>251-265>267. GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR LSZ266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...07 MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
534 AM EST TUE DEC 10 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 426 PM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. ONE SHORTWAVE TROUGH EXTENDED FROM NW ONTARIO THROUGH WRN LAKE SUPERIOR WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING FROM SE SASK TOWARD THE NRN PLAINS. AT THE SFC...A WEAK RIDGE OVER WRN MN SEPARATED LOWS NE OF LAKE SUPERIOR AND OVER NE MONTANA. WSW WINDS ACROSS WRN LAKE SUPERIOR WERE SLOWLY VEERING AS THE SHRTWV ADVANCES THROUGH THE AREA. THE INITIAL DOMINANT BAND THROUGH THE NRN KEWEENAW EARLY THIS AFTERNOON HAD LIFTED BACK TO THE NORTH. HOWEVER...MULTIPLE WIND PARALLEL BANDS INTO THE NRN HALF OF THE KEWEENAW HAVE INTENSIFIED THIS AFTERNOON...AIDED BY THE SHRTWV WHICH HAS BOOSTED INVERSION HEIGHTS TO AROUND 9K FT AS 850 MB TEMPS DROP INTO THE -18C TO -21C RANGE. TONIGHT... THE HIGH RES MODELS WERE IN GOOD AGREEMENT AND SUPPORT UPSTREAM TRENDS OF LOW LEVEL WINDS VEERING THIS EVENING WHICH SHOULD PUSH HEAVY LES BANDS OVER THE KEWEENAW GRADUALLY TO THE SOUTH. HOWEVER...THE SRN EXTENT OF THE LES IS EXPECTED TO REMAIN MAINLY NORTH OF M-38. SLR VALUES MAY BE LIMITED BY THE VERY COLD INCOMING ARCTIC AIRMASS WHICH WILL KEEP THE DGZ BELOW 2K FT. GIVEN THE FAVORABLE LOW LEVEL CONV PERSISTING THROUGH MUCH OF THE EVENING BEFORE WINDS BACK AHEAD OF THE NEXT SHORTWAVE...ADDITIONAL ACCUMULATIONS IN THE 3 TO 6 INCH RANGE ARE LIKELY. BY 12Z...EXPECT THAT THE HEAVIER LES SHOULD LIFT TOWARD EAGLE RIVER AND COPPER HARBOR BEFORE MOVING OFFHSORE TUE MORNING. STRONG WRLY GUSTING TO 35 MPH WILL ALSO CAUSE SIGNIFICANT BLOWING AND DRIFTING IN OPEN AREAS WITH VSBY AOB 1/4SM IN THE HEAVIER LES BANDS BEFORE TAPER OFF AFTER 03Z/TUE. TEMPERATURES DROPPING INTO THE ZERO TO 10 BELOW RANGE WITH WINDS OF 10 TO 15 MPH MAY DROP WIND CHILL VALUES TO 15 BELOW TO 25 BELOW THIS EVENING. HOWEVER...WINDS ARE EXPECTED TO DIMINISH TO 7 MPH OR LESS OVER THE COLDER INLAND AREAS...KEEPING WIND CHILLS FROM REACHING ADVISORY THRESHOLD. IN ADDITION...CLOUDS WILL THICKEN LATE AS THE SHRTWV APPROACHES BRINGING SLOWLY CLIMBING TEMPS LATE. TUESDAY... THE SASK SHRTWV WILL MOVE THROUGH THE REGION WITH MODERATE TO STRONG 700-300 MB QVECTOR CONV. EVEN THOUGH THE STRONGEST FORCING IS EXPECTED JUST TO THE SOUTH OF UPPER MICHIGAN...IT SHOULD STILL BE STRONG ENOUGH OVER UPPER MI TO SQUEEZE OUT SOME LIGHT SNOW WITH A FEW HUNDREDTHS QPF IN THE VERY DRY AIRMASS. OVERALL ACCUMULATIONS SHOULD REMAIN BELOW A HALF INCH BUT SHOULD BE WIDESPREAD ENOUGH TO INCLUDE LIKELY POPS. VEERING WINDS IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. ANOTHER PERIOD OF HEAVIER LES IS EXPECTED WITH THIS FEATURE THAT COULD PRODUCE 2 TO 4 INCHES OF SNOW. SINCE THERE IS A GAP BETWEEN THE MON NIGHT LES AND THE NEXT BATCH THE HEADLINE WAS NOT EXTENDED AT THIS TIME. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 534 AM EST TUE DEC 10 2013 CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE WEEKEND. WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL TONIGHT. THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE. INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES INTENSITY GREATLY WEDNESDAY EVENING. A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA. HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING. MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES WILL NOT BE OUT OF THE QUESTION QUITE YET. THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE ENOUGH TO DISRUPT REMAINING LES. FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A DUSTING OF SNOW. MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1239 AM EST TUE DEC 10 2013 KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE FROM THE NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST PERIOD. KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AND THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE THROUGH TUE EVENING. KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY TUE AFTERNOON. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 426 PM EST MON DEC 9 2013 A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH MOVING THROUGH LATE THIS AFTERNOON WILL BRING WRLY GALES OF 35 TO 40 KNOTS ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING. AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND COULD PRODUCE GALE FORCE WIND GUSTS TO 35 KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 11 AM THIS MORNING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ002-003. LAKE EFFECT SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST WEDNESDAY FOR MIZ001. LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST WEDNESDAY FOR MIZ004-084. LAKE EFFECT SNOW ADVISORY FROM NOON TODAY TO 11 AM CST WEDNESDAY FOR MIZ009. LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST THURSDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ006. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ245-248>251-265>267. GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR LSZ266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
340 AM MST TUE DEC 10 2013 .SHORT TERM...VALID FOR TDY AND WED... ALBERTA CLIPPER NUMBER TWO ARRIVES TODAY WITH A HIGHER PROBABILITY OF MORE WIDESPREAD 1 TO 2 INCH SNOWFALL...BUT WIND ISSUES CONTINUE BOTH AHEAD OF IT SOUTH CENTRAL...AND BEHIND IT SOUTHEAST /ALTHOUGH WE DO NOT EXPECT THEM TO BE AS STRONG AS ON MON THERE/. TODAY...WE UPGRADED THE LIVINGSTON AREA AND BEARTOOTH FOOTHILLS TO A BLIZZARD WARNING OVERNIGHT GIVEN FREQUENT 70+ MPH WIND GUSTS AND 1/4SM VISIBILITY AT THE LIVINGSTON AIRPORT. SPOTTERS NEAR NYE ALSO REPORTED MAJOR DRIFTING AND LOW VISIBILITY. THE LOW-LEVEL PRESSURE GRADIENT SHOULD EVER-SO-SLOWLY RELAX AFTER SUNRISE AS A SHORT WAVE IN CENTRAL CANADA HEADS SOUTHEAST...BUT THE IMPACTS WILL BE SEVERE INTO AT LEAST THE FIRST PART OF THE MORNING...SO THE HEADLINE RUNS UNTIL 19 UTC. THE REST OF THE WINTER WEATHER ADVISORY FOR PARTS OF SOUTH CENTRAL MT THAT WAS ORIGINALLY SET TO EXPIRE VERY EARLY THIS MORNING HAS ALSO BEEN EXTENDED UNTIL 19 UTC BASED ON RECENT TRENDS IN OBSERVATIONS. SINCE WINDS HAVE TAKEN ON A GAP NATURE...THERE IS ALSO SIGNIFICANT FLOW IN THE PARADISE VALLEY...WHERE WE DID HAVE A REPORT OF BLOWING AND DRIFTING SNOW LATE MON EVENING. WE THEREFORE ADDED THE PARADISE VALLEY TO A WINTER WEATHER ADVISORY TOO. MEANWHILE...WE HOISTED YET ANOTHER WINTER WEATHER ADVISORY FOR ALL OF SOUTHEASTERN MT FROM 15 UTC THROUGH 04 UTC. A DEEPENING SURFACE LOW WILL DROP INTO SOUTHERN ND BY AFTERNOON...WITH INCREASING COLD AIR ADVECTION AND NOTABLE SURFACE PRESSURE RISES IN ITS WAKE. WIND SPEEDS ALOFT NEAR 850 HPA ARE ONLY SIMULATED TO BE NEAR 30 KT /NOT 50 KT LIKE ON MON/...BUT THE SITUATION WILL LIKELY YIELD 25 MPH OR HIGHER GUSTS FOR AT LEAST A FEW HOURS. THAT SHOULD BE ENOUGH FOR A ROUND OF BLOWING AND DRIFTING SNOW. ROBUST QG-FORCING WILL BRING A SOLID ROUND OF SNOW TO SOUTHEAST MT DURING THE DAY TOO...WITH 1 TO 2 INCHES OF ACCUMULATION LIKELY. THE FALLING SNOW WILL THUS ADD TO THE IMPACTS OF BLOWING AND DRIFTING AND ALREADY ICY ROADS...ENOUGH TO NECESSITATE ANOTHER HEADLINE. NOTE THAT THERE IS A CHANCE MODEL SIMULATIONS ARE UNDERESTIMATING SURFACE WIND SPEEDS IN THE WAKE OF THE FRONT GIVEN THE EXPECTED COLD AIR ADVECTION. WE WILL THUS NEED TO KEEP A CLOSE EYE ON TRENDS THROUGH THE DAY. BY AFTERNOON...THE COLD FRONT TRAILING THE ALBERTA CLIPPER WILL BE DROPPING THROUGH SOUTH CENTRAL MT...WHICH SHOULD ALLOW THE WIND TO BECOME UPSLOPE IN TRAJECTORY. LIKELY POPS ARE THEREFORE STILL GOOD FOR PLACES LIKE BILLINGS AND SOUTHERN BIG HORN COUNTY...WITH LIGHT ACCUMULATIONS LIKELY BEHIND THE FRONT...ESPECIALLY IN SOUTHERN BIG HORN COUNTY IF YOU BELIEVE RECENT RAP SIMULATIONS. TONIGHT...FORCING WITH THE SHORT WAVE IS ALL BUT GONE BY THE EARLY EVENING...SO WE WILL MAINLY BE LEFT WITH UPSLOPE FLOW AND RESIDUAL CYCLONIC FLOW FOR MAKING SNOW IN SOUTH CENTRAL MT AND SOUTHEASTERN MT...RESPECTIVELY. THE UPSLOPE WOULD HAVE THE BETTER CHANCE OF ANY MEANINGFUL ACCUMULATIONS...ESPECIALLY IF ANY OROGRAPHIC SNOW BANDS MANAGE TO FORM AND IMPACT PLACES LIKE BILLINGS /SOMETHING WHICH IS NOT COMPLETELY OUT OF THE QUESTION/. EVERYTHING SETTLES DOWN BY 06 UTC THOUGH AS LOW-LEVEL GRADIENTS REVERSE AND UPSLOPE DIMINISHES. WED...WE WILL FINALLY HAVE A RELATIVELY QUIET DAY...SAVE FOR WINDS AROUND THE FOOTHILLS...WHICH SHOULD AGAIN REACH ADVISORY LEVELS AS AN IDAHO FALLS TO LEWISTOWN SURFACE PRESSURE GRADIENT ON THE ORDER OF 15 HPA DRIVES STRONG WINDS AROUND LIVINGSTON AND NYE YET AGAIN. IF THE SNOW HAS NOT HARDENED SUFFICIENTLY FROM THE DRIFTING DURING THE LAST TWO DAYS...A WINTER WEATHER ADVISORY WILL PROBABLY BE THE OPERATIVE HEADLINE ONCE AGAIN WED INTO WED NIGHT. ELSEWHERE...WIND SPEEDS MAY BE A BIT BREEZY AT TIMES THANKS TO MIXING...BUT IMPACTS SHOULD BE MUCH LOWER THAN EARLIER DAYS. A WARMING TREND WILL BE IN THE CARDS ALOFT...ALBEIT A SLOW ONE...BUT THE DEGREE OF WARMING AT THE SURFACE IS A LOW-CONFIDENCE ITEM. SCHULTZ .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... THURSDAY SHOULD BE THE WARMEST DAY OF THE WEEK AS A DOWNSLOPE WIND PATTERN COMBINES WITH A WESTERLY FLOW ALOFT TO BRING GOOD MIXING AND A FEW TEMPERATURES COULD CLIMB ABOVE FREEZING. IT WILL CERTAINLY BE WINDY FOR THE WESTERN ZONES AND HAVE RAISED WINDS IN THE GAP FLOW AREAS AND SUSPECT THERE MAY BE ANOTHER HIGH WIND EVENT WHICH COULD BLOW SNOW AROUND...BUT THE TEMPERATURES ARE EXPECTED TO BE WARMER. COLD FRONT BACKS INTO THE CENTRAL AND EASTERN AREAS ON FRIDAY FOR A COOL DOWN ESPECIALLY FOR SOUTHEAST MONTANA AND A RETURN OF SNOW TO THE FORECAST. A LITTLE BIT OF MODERATION FRIDAY NIGHT AS A DISTURBANCE BRINGS A ROUND OF PRESSURE FALLS AND THEN A STRONGER COLD SHOT COMES ON SATURDAY. THIS SYSTEM WILL HAVE A STRONGER CLIPPER EFFECT ACROSS SOUTHEAST MONTANA AND WILL HAVE TO WATCH FOR A ROUND OF NORTHWEST WINDS BRINGING A BETTER CHANCE FOR ACCUMULATING AND BLOWING SNOW. FLOW SWITCHES FROM NORTHWESTERLY FRIDAY AND SATURDAY TO A BIT MORE WESTERLY ON SUNDAY AND MONDAY FAVORING MODERATING TEMPERATURES AND SHIFTING BEST CHANCES FOR PRECIPITATION AWAY FROM THE REGION AS DOWNSLOPE BECOMES A STRONGER FACTOR. FLOW LOOKS TO TURN NORTHWESTERLY ON TUESDAY FOR A RETURN OF THE CLIPPER EXPRESS. BORSUM && .AVIATION... WINTER WEATHER WILL CONTINUE TO IMPACT THE REGION. BLIZZARD CONDITIONS WILL IMPACT KLVM WITH VLIFR UNTIL MIDDAY. CONDITIONS WILL IMPROVE BUT MORE SNOW WILL BRING LOWER CEILINGS AND KEEP VISIBILITIES NO BETTER THAN MVFR. KMLS WILL HAVE THE SNOW ARRIVE THIS AFTERNOON COMBINING WITH INCREASED WINDS PRODUCING IFR CONDITIONS. KBIL AND KSHR WILL SEE LIGHTER SNOWFALL AND LESS WIND SO CONDITIONS WILL DECREASE TO MVFR THIS AFTERNOON AND APPROACH IFR AT TIMES. BORSUM && .PRELIMINARY POINT TEMP/POPS... TDY WED THU FRI SAT SUN MON ------------------------------------------------------- BIL 024 005/029 022/035 018/034 015/032 021/035 022/033 6/S 61/N 11/N 12/J 21/B 11/B 11/B LVM 019 007/026 022/034 021/034 019/034 021/032 021/028 4/S 41/Q 11/N 22/J 11/N 11/N 21/N HDN 024 901/027 016/037 015/032 012/030 018/034 020/033 8/S 61/B 11/B 12/J 21/B 12/J 11/B MLS 019 907/023 012/032 013/026 010/022 015/030 020/031 9/S 20/B 01/B 12/J 21/B 22/J 11/B 4BQ 022 903/022 013/036 017/031 012/027 018/031 020/032 9/S 31/B 00/B 02/J 21/B 22/J 01/B BHK 016 911/017 011/029 012/022 010/018 013/028 019/029 9/S 20/B 01/B 12/J 21/E 12/J 11/B SHR 024 901/027 016/038 016/034 014/033 018/036 020/033 5/S 51/B 00/B 12/J 21/B 11/B 21/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR ZONES 28-34-41-42-63-64. WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM THIS MORNING TO 9 PM MST THIS EVENING FOR ZONES 31>33-36-37-58. BLIZZARD WARNING IN EFFECT UNTIL NOON MST TODAY FOR ZONES 65-66. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1026 AM EST TUE DEC 10 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM TUESDAY...COMPLEX WEATHER SCENARIO FOR TODAY WITH LOW PRESSURE SYSTEM OVER THE CAROLINAS. WARM AIR STREAMING NORTHWARD AHEAD OF COLD FRONT OVER WESTERN CAROLINAS. TEMPS ALREADY HIT 70 AT WILMINGTON AIRPORT AND WIDESPREAD 60S AS WARMER AIR IS MIXING DOWN WITH A DEEPER AND INCREASING WARM AND MOIST SOUTHERLY FLOW. DENSER COLDER AIR HELD ON OVER CENTRAL TO NORTHERN CAROLINAS...JUST UPSTREAM OF FORECAST AREA. THE WARM AIR ALOFT RIDING OVER COLD AIR INLAND PRODUCING DECENT ISENTROPIC LIFT WITH STEEP INVERSION IN PLACE BASICALLY JUST WEST AND NORTH OF AREA WHERE WEDGE HELD ON. TEMPS WILL PEAK THIS MORNING BUT CLOUDS...PCP WILL KEEP TEMPS FROM RISING TOO MUCH IN MOST PLACES AND THEN COLD FRONT WILL PUSH THROUGH BY EARLY TO MID AFTN. TEMPS AT H85 WILL RISE UP TO 12C BY NOON TIME AND THEN WILL PLUMMET THROUGH THIS AFTN DOWN CLOSE TO 4C BY MIDNIGHT. COOLER WATERS KEEPING TEMPS MUCH COOLER...CLOSER TO 60...ALONG THE BEACHES AND UP THROUGH BRUNSWICK COUNTY WHERE ON SHORE FLOW IS MAXIMIZED. THIS IS ALSO LEADING TO ANOTHER ROUND OF SEA FOG AS WARMER MOISTER AIR JUST ABOVE THE SURFACE IS MOVING ATOP THE COOLER WATERS. ISSUED SPECIAL WEATHER STATEMENT TO ADDRESS LOCALIZED FOG OVER SHELF WATERS SOUTH MAINLY ADVECTING FROM SOUTH OF CAPE FEAR ON SHORE OVER BRUNSWICK COUNTY. BEST ISENTROPIC LIFT WILL REMAIN JUST NORTH AND WEST OF AREA WHERE COOLER AIR IS LOCATED BUT SHOULD SEE MORE CONVECTIVE TYPE PCP IN WARM AND MORE UNSTABLE AIR MASS AHEAD OF FRONT. LLJ UP TO 55 KTS PUMPING PLENTY OF WARM AND MOIST AIR AHEAD OF COLD FRONT. CONVECTIVE INDICES LOOK LIKE WE COULD SEE SOME LOW TOP CONVECTION AND POSSIBLY A RUMBLE OF THUNDER. BEST LIFT SHOULD COME JUST AHEAD OF COLD FRONT THROUGH THIS AFTERNOON LEAVING A NARROW WINDOW BUT MAY INCLUDE MENTION OF ISO THUNDER IN GRIDS. SFC BASED CAPE VALUES REACH UP TO 600 JKG. MAY SEE MORE STABLE MARINE LAYER COME INTO PLAY AS STORMS MOVE CLOSER TO THE COAST...BUT EXPECT SHOWERS AHEAD OF FRONT THROUGH EARLY AFTERNOON. THE COLD FRONT BACK TOWARD THE MOUNTAINS THIS MORNING WILL GET A PUSH FROM MID TO UPPER TROUGH BY MID AFTERNOON AND SHOULD PROGRESS THROUGH THE I-95 CORRIDOR AROUND 1PM AND REACH THE COAST BY 3 PM. PLENTY OF COLD AND DRY AIR WILL ADVECT IN BEHIND FRONT AND SCOUR OUT ALL THE LOW CLOUDS...FOG AND ANY SHOWERS OR PCP ACROSS THE AREA. THIS WILL LEAD TO FALLING TEMPS ACROSS THE AREA THROUGH THIS EVENING. AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS A STRONG COLD ADVECTION REGIME SETS UP WITH ABOUT A 40 DEGREE DROP IN BOTH TEMPS AND DEWPOINT TEMPS BY MORNING AS COLD AND DRY AIR COMES RUSHING IN. CLEARING SKIES OVERNIGHT WILL COMBINE WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP INTO THE LOWER TO MID 30S. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY. THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN CLOUDS OUT OF THE MIX FOR THE MOST PART. A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH MOST AREAS SEEING MID TO UPPER 20S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING. HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO CHANGES TO TEMPERATURE FORECAST. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95 CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON. CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM TUESDAY...DECIDED ON A DENSE FOG ADVISORY AFTER ALL. VIS SAT PIX INDICATE THE FOG CONTINUING TO INCREASE IN COVERAGE EVEN AS BEING RAPIDLY ADVECTED NORTH AND EAST. ADVISORY FOR ALL ZONES TIL 18Z...AFTER WHICH COLD FRONT WILL RAPIDLY BLOW IT OUT TO SEA. AS OF 930 AM TUESDAY...SEA FOG DEVELOPED ONCE AGAIN AS WARM AIR JUST ABOVE THE SURFACE WAS MOVING OVER COOL SHELF WATERS...MORE WIDESPREAD JUST SOUTH OF BRUNSWICK. ISSUED SPS FOR NOW BUT MAY HAVE TO ISSUE DENSE FOG ADVISORY. SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT MOVES ACROSS THE WATERS...WITH LIMITED FETCH CAUSING NEAR- SHORE SEAS TO SUBSIDE TO BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT. CURRENT OBS SHOW CONDITIONS OVER THE COASTAL WATERS ARE STILL ON THE BENIGN SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4 FT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO 15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING WINDS AND SEAS FOR SATURDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ250- 252-254-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250- 252-254-256. && $$ NEAR TERM...MBB/RGZ SHORT TERM...SHK LONG TERM...SHK AVIATION...DL MARINE...SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1004 AM EST TUE DEC 10 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM TUESDAY...COMPLEX WEATHER SCENARIO FOR TODAY WITH LOW PRESSURE SYSTEM OVER THE CAROLINAS. WARM AIR STREAMING NORTHWARD AHEAD OF COLD FRONT OVER WESTERN CAROLINAS. TEMPS ALREADY HIT 70 AT WILMINGTON AIRPORT AND WIDESPREAD 60S AS WARMER AIR IS MIXING DOWN WITH A DEEPER AND INCREASING WARM AND MOIST SOUTHERLY FLOW. DENSER COLDER AIR HELD ON OVER CENTRAL TO NORTHERN CAROLINAS...JUST UPSTREAM OF FORECAST AREA. THE WARM AIR ALOFT RIDING OVER COLD AIR INLAND PRODUCING DECENT ISENTROPIC LIFT WITH STEEP INVERSION IN PLACE BASICALLY JUST WEST AND NORTH OF AREA WHERE WEDGE HELD ON. TEMPS WILL PEAK THIS MORNING BUT CLOUDS...PCP WILL KEEP TEMPS FROM RISING TOO MUCH IN MOST PLACES AND THEN COLD FRONT WILL PUSH THROUGH BY EARLY TO MID AFTN. TEMPS AT H85 WILL RISE UP TO 12C BY NOON TIME AND THEN WILL PLUMMET THROUGH THIS AFTN DOWN CLOSE TO 4C BY MIDNIGHT. COOLER WATERS KEEPING TEMPS MUCH COOLER...CLOSER TO 60...ALONG THE BEACHES AND UP THROUGH BRUNSWICK COUNTY WHERE ON SHORE FLOW IS MAXIMIZED. THIS IS ALSO LEADING TO ANOTHER ROUND OF SEA FOG AS WARMER MOISTER AIR JUST ABOVE THE SURFACE IS MOVING ATOP THE COOLER WATERS. ISSUED SPECIAL WEATHER STATEMENT TO ADDRESS LOCALIZED FOG OVER SHELF WATERS SOUTH MAINLY ADVECTIN FROM SOUTH OF CAPE FEAR ON SHORE OVER BRUNSWICK COUNTY. BEST ISENTROPIC LIFT WILL REMAIN JUST NORTH AND WEST OF AREA WHERE COOLER AIR IS LOCATED BUT SHOULD SEE MORE CONVECTIVE TYPE PCP IN WARM AND MORE UNSTABLE AIR MASS AHEAD OF FRONT. LLJ UP TO 55 KTS PUMPING PLENTY OF WARM AND MOIST AIR AHEAD OF COLD FRONT. CONVECTIVE INDICES LOOK LIKE WE COULD SEE SOME LOW TOP CONVECTION AND POSSIBLY A RUMBLE OF THUNDER. BEST LIFT SHOULD COME JUST AHEAD OF COLD FRONT THROUGH THIS AFTERNOON LEAVING A NARROW WINDOW BUT MAY INCLUDE MENTION OF ISO THUNDER IN GRIDS. SFC BASED CAPE VALUES REACH UP TO 600 JKG. MAY SEE MORE STABLE MARINE LAYER COME INTO PLAY AS STORMS MOVE CLOSER TO THE COAST...BUT EXPECT SHOWERS AHEAD OF FRONT THROUGH EARLY AFTERNOON. THE COLD FRONT BACK TOWARD THE MOUNTAINS THIS MORNING WILL GET A PUSH FROM MID TO UPPER TROUGH BY MID AFTERNOON AND SHOULD PROGRESS THROUGH THE I-95 CORRIDOR AROUND 1PM AND REACH THE COAST BY 3 PM. PLENTY OF COLD AND DRY AIR WILL ADVECT IN BEHIND FRONT AND SCOUR OUT ALL THE LOW CLOUDS...FOG AND ANY SHOWERS OR PCP ACROSS THE AREA. THIS WILL LEAD TO FALLING TEMPS ACROSS THE AREA THROUGH THIS EVENING. AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS A STRONG COLD ADVECTION REGIME SETS UP WITH ABOUT A 40 DEGREE DROP IN BOTH TEMPS AND DEWPOINT TEMPS BY MORNING AS COLD AND DRY AIR COMES RUSHING IN. CLEARING SKIES OVERNIGHT WILL COMBINE WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP INTO THE LOWER TO MID 30S. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY. THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN CLOUDS OUT OF THE MIX FOR THE MOST PART. A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH MOST AREAS SEEING MID TO UPPER 20S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING. HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO CHANGES TO TEMPERATURE FORECAST. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95 CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON. CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM TUESDAY...SEA FOG DEVELOPED ONCE AGAIN AS WARM AIR JUST ABOVE THE SURFACE WAS MOVING OVER COOL SHELF WATERS....MORE WIDESPREAD JUST SOUTH OF BRUNSWICK. ISSUED SPS FOR NOW BUT MAY HAVE TO ISSUE DENSE FOG ADVISORY. SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT MOVES ACROSS THE WATERS...WITH LIMITED FETCH CAUSING NEAR- SHORE SEAS TO SUBSIDE TO BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT. CURRENT OBS SHOW CONDITIONS OVER THE COASTAL WATERS ARE STILL ON THE BENIGN SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4 FT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO 15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING WINDS AND SEAS FOR SATURDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250- 252-254-256. && $$ SYNOPSIS... NEAR TERM...RGZ SHORT TERM...SHK LONG TERM...SHK AVIATION...DL MARINE...SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
647 AM EST TUE DEC 10 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 6:45 AM TUESDAY...CANCELED DENSE FOG ADVISORY EARLY. OTHERWISE FORECAST CONTINUES WITHOUT CHANGES. PREVIOUS DISCUSSION FOLLOWS: QUASI-STATIONARY FRONT WAVERING ACROSS THE FORECAST AREA WILL PUSH OFFSHORE AS A COLD FRONT THIS AFTERNOON AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS. TEMPERATURES WILL PEAK LATE THIS MORNING IN THE LOWER TO MID 60S BEFORE A STRONG COLD ADVECTIVE REGIME SETS UP AND DROPS READINGS BACK INTO THE 50S. LIGHT WINDS AND CLEARING SKIES OVERNIGHT WILL COMBINE WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP INTO THE LOWER TO MID 30S. PATCHY LIGHT RAIN AND DRIZZLE ARE CURRENTLY MOVING NORTHEAST ACROSS OUR INLAND COUNTIES ALONG THE FRONTAL BOUNDARY. THE RAIN SHIELD WILL SPREAD SOUTHEAST ACROSS THE FORECAST AREA THIS MORNING AS THE COLD FRONT CONSOLIDATES AND DROPS SOUTHEAST. SHOWER ACTIVITY SHOULD END BY AROUND MID AFTERNOON AS THE FRONT MOVES WELL OFFSHORE. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY. THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN CLOUDS OUT OF THE MIX FOR THE MOST PART. A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH MOST AREAS SEEING MID TO UPPER 20S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING. HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO CHANGES TO TEMPERATURE FORECAST. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95 CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON. CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 6:45 AM TUESDAY...CANCELED DENSE FOG ADVISORY EARLY. OTHERWISE FORECAST CONTINUES WITHOUT CHANGES. PREVIOUS DISCUSSION FOLLOWS: SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT MOVES ACROSS THE WATERS...WITH LIMITED FETCH CAUSING NEAR-SHORE SEAS TO SUBSIDE TO BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT. CURRENT OBS SHOW CONDITIONS OVER THE COASTAL WATERS ARE STILL ON THE BENIGN SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4 FT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO 15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING WINDS AND SEAS FOR SATURDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250- 252-254-256. && $$ SYNOPSIS...SHK NEAR TERM...REK SHORT TERM...SHK LONG TERM...SHK AVIATION...DL MARINE...REK/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
633 AM EST TUE DEC 10 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM TUESDAY...QUASI-STATIONARY FRONT WAVERING ACROSS THE FORECAST AREA WILL PUSH OFFSHORE AS A COLD FRONT THIS AFTERNOON AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS. TEMPERATURES WILL PEAK LATE THIS MORNING IN THE LOWER TO MID 60S BEFORE A STRONG COLD ADVECTIVE REGIME SETS UP AND DROPS READINGS BACK INTO THE 50S. LIGHT WINDS AND CLEARING SKIES OVERNIGHT WILL COMBINE WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP INTO THE LOWER TO MID 30S. PATCHY LIGHT RAIN AND DRIZZLE ARE CURRENTLY MOVING NORTHEAST ACROSS OUR INLAND COUNTIES ALONG THE FRONTAL BOUNDARY. THE RAIN SHIELD WILL SPREAD SOUTHEAST ACROSS THE FORECAST AREA THIS MORNING AS THE COLD FRONT CONSOLIDATES AND DROPS SOUTHEAST. SHOWER ACTIVITY SHOULD END BY AROUND MID AFTERNOON AS THE FRONT MOVES WELL OFFSHORE. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY. THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN CLOUDS OUT OF THE MIX FOR THE MOST PART. A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH MOST AREAS SEEING MID TO UPPER 20S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING. HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO CHANGES TO TEMPERATURE FORECAST. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95 CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON. CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM TUESDAY...SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT MOVES ACROSS THE WATERS...WITH LIMITED FETCH CAUSING NEAR-SHORE SEAS TO SUBSIDE TO BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT. CURRENT OBS SHOW CONDITIONS OVER THE COASTAL WATERS ARE STILL ON THE BENIGN SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4 FT SEAS. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO 15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING WINDS AND SEAS FOR SATURDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR SCZ017-023-024-032-033-039-053>056. NC...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NCZ087-096-099-105>110. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR AMZ250-252-254-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250- 252-254-256. && $$ SYNOPSIS...SHK NEAR TERM...REK SHORT TERM...SHK LONG TERM...SHK AVIATION...43
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
844 AM EST TUE DEC 10 2013 .SYNOPSIS... SNOW WILL MOVE QUICKLY TO THE EAST THIS MORNING. A VERY COLD AND BRISK WEST TO NORTHWEST FLOW WILL DEVELOP IN THE WAKE OF THIS SYSTEM...AND BRING MUCH COLDER AIR WITH BELOW NORMAL TEMPERATURES GRIPPING THE REGION THROUGH MID TO LATE WEEK. MODERATE TO LOCALLY HEAVY LAKE EFFECT SNOWS ARE ALSO FORECAST IN PERENNIAL SNOWBELT ACROSS THE NORTHWEST MOUNTAINS INTO THE SECOND HALF OF THE WEEK. ELSEWHERE...IT WILL BE GENERALLY COLD AND DRY. THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME WITH ANOTHER STORM SYSTEM LIKELY AFFECTING THE AREA OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 830 AM UPDATE... IT TOOK A WHILE TO MOISTEN THE LOWER ATMOS THIS MORNING. SNOW JUST NOT FALLING IN THE WRN HALF OF THE ADVY AREA. THE AREA OF LIGHT SNOW IN WRN PA IS DIMINISHING QUICKLY AND SHOULD BE GONE BY 10 AM. HAVE CANCELLED THE ADVY FOR LOCATIONS WEST OF FRANKLIN COUNTY. EVEN AREAS TO THE NORTH OF HARRISBURG ARE EASILY IN JEOPARDY OF NOT RECEIVING MORE THAN AN INCH OR TWO OF SNOW TOTAL. HAVE ADJUSTED POPS/TIMING/AMNTS ACCORDINGLY. PREV... DESPITE A LACK OF -SN BEING REPORTED IN THE SFC OBS...A QUICK GLANCE AT AREA WEBCAMS SHOWS SNOW IS REACHING THE GROUND IN SRN PA. EMBEDDED WITHIN THE BASE OF A PROGRESSIVE 500MB TROUGH...FAST- MOVG SHORTWAVE ENERGY AND STG HEIGHT FALLS /APPROACHING -200M IN 12HR/ WILL RACE EWD ACROSS THE UPPER OH VLY EARLY THIS MORNING AND MOVE THROUGH CENTRAL PA BTWN 15-21Z. DOWNSTREAM WARM AIR/MSTR ADVECTION INTERACTING WITH STRONG DIVERGENCE ALOFT ALONG THE RIGHT-ENTRANCE REGION OF A POWERFUL 175KT UPPER JET STREAK WILL CONTINUE TO ALLOW FOR A RAPID NEWD EXPANSION OF LGT-MOD SNOW QUICKLY SPREADING ACROSS SOUTH-CENTRAL AND SERN PA EARLY THIS MORNING. A CONSENSUS OF SHORT-RANGE HIRES MODELS SHOWS THE PERIOD OF MOST INTENSE SNOWS OCCURRING FROM MID-LATE MORNING BEFORE SNOW QUICKLY TAPERS OFF FROM W-E BY MID TO LATE AFTN. THE RAPID PROGRESSION OF THIS SYSTEM SHOULD LIMIT WIDESPREAD HEAVY AMTS WITH SNFL TOTALS GENERALLY IN THE 1-3/2-4" RANGE. HOWEVER...LOCALLY HEAVIER AMTS ARE POSSIBLE ESPECIALLY ALONG/S OF I-81 WHERE ENHANCED LOW-MID LVL FGEN AND MESO BANDING MAY SUPPORT A NARROW SWATH OF 4-6". THE LATEST RUC ALONG WITH THE HIRES WRF/NMM SUGGEST THE GREATEST POTENTIAL FOR HEAVY SNOW BANDING AND SNFL RATES BTWN 0.5-1" PER HOUR IS ALONG/S OF RT 30...WHERE THE FINAL NDFD SNFL GRAPHICS SHOW STORM TOTALS OF 3-5". THE ONLY CHANGE TO THE WW ADVY WAS TO BREAKOUT THE LWR SUSQ COUNTIES TO HIGHLIGHT EXPECTED HIER AMTS. THE MESO MODELS SHOW THE BULK OF THE ACCUM SNOW ENDING OVER THE LAURELS AND CNTRL MTNS BY 18Z...AND A FEW HOURS LATER IN THE MID- LWR SUSQ. INC WEST WINDS AND FALLING TEMPS WILL DROP WIND CHILLS SINGLE DIGITS AND LOW TEENS ACRS THE WRN ALLEGHENIES BY DARK. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... IN THE WAKE OF THE FAST-MOVING WINTER SYSTEM...A VIGOROUS CYCLONIC/NW FLOW PATTERN WILL GRIP THE REGION WITH BELOW NORMAL TEMPS AND LAKE EFFECT SNOWS THROUGH THE END OF THE WEEK. A REINFORCING SHOT OF COLD AIR FOLLOWING THE PASSAGE OF A NRN CLIPPER ON WED WILL HELP SUPPORT PERSISTENT...MAINLY W-E ORIENTED LES BANDS OVER THE PERENNIAL NW SNOWBELT IN NRN WARREN/MCKEAN COS WITH ACCUMS IN EXCESS OF 6" POSSIBLE BY THE END OF THE PD. OTHER THAN THE LES SNOW IN THE NW MTNS...MUCH OF THE REMAINDER OF THE AREA WILL BE COLD AND DRY. A CONSENSUS OF ALL MAX TEMP GUIDANCE SHOWS DAYTIME DEPARTURES OF -20F ACROSS MUCH OF THE AREA THU. WIND CHILLS WILL BE VERY COLD ESPECIALLY AT NIGHT AND IN THE EARLY MORNING WITH VALUES IN THE SINGLE DIGITS EITHER SIDE OF ZERO. HIGHLIGHTED THE WIND CHILLS IN THE HWO. THE GFS/ECMWF EVENTUALLY SHOW THE LAKE EFFECT WINDING DOWN AS HIGH PRESSURE ARRIVES IN THE MID-ATLC ON FRIDAY. && .LONG TERM /SATURDAY THROUGH MONDAY/... THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME BY THE WEEKEND...AS THE ENERGETIC SPLIT FLOW UPSTREAM MERGES OVER THE CENTRAL STATES...ALLOWING LOW PRESSURE TO DEVELOP IN THE LWR MS REGION AND TRACK NEWD INTO THE MID-ATLC/NORTHEAST STATES. WHILE THERE IS REASONABLE CONVERGENCE OF SOLUTIONS ON A STORM SYSTEM...THE DETAILS WILL NEED SORTING-OUT AT SHORTER RANGES TO DETERMINE SENSIBLE WX IMPACTS SUCH AS TIMING AND PTYPES. AT FIRST GLANCE...THE SET-UP IS SOMEWHAT SIMILAR TO THIS PAST SUNDAY`S SYSTEM WITH MIXED PRECIP AGAIN A CONCERN. THE COLD AIR PRECEDING THE NEW SYSTEM SHOULD BE MORE ROBUST WHICH SUGGESTS AN INCREASED CHANCE FOR FROZEN/FREEZING PTYPES. INCREASED POPS AROUND DAY 5 WITH REASONABLE MODEL AGREEMENT HOWEVER CONFIDENCE IN TIMING IS BELOW AVG GIVEN DIFFS IN THE OPRN GFS/EC AND THEIR RESPECTIVE ENSEMBLE MEANS. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... SNOW HAS BEGUN TO FALL ACROSS SOUTHEASTERN PA...WITH LIFR CONDITIONS AT MDT AND LNS. THESE CIGS AND VSBYS SHOULD CONTINUE THROUGH THE MORNING...TAPERING OFF BETWEEN 16 TO 18Z. THIS IS DUE TO A FAST-MOVING LOW PRESSURE SYSTEM THAT WILL SPREAD A PERIOD OF SNOW ACROSS MAINLY SOUTHERN PA UNTIL 18Z. LIGHTER SNOW WILL FALL FURTHER NORTH...WITH ONE TO THREE ACCUMULATIONS POSSIBLE. MVFR CIGS AND VSBYS REMAIN POSSIBLE THROUGHOUT THE REST OF THE TAF SITES THROUGH THIS TIMEFRAME. AFTER 18Z EXPECT CONDITIONS TO IMPROVE...WITH VFR DOMINATING CONDITIONS AFTER 22Z. THE ONLY CAVEAT WILL BE BFD WHERE THERE SHOULD BE A DROP IN CIGS AND VSBYS TO MVFR/IFR OVERNIGHT TONIGHT DUE TO NW FLOW AND LAKE ENHANCED SHOWERS. OUTLOOK... WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS. THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS. FRI...NO SIG WX EXPECTED. SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR PAZ028-036-049>053-056>059-063>066. && $$ SYNOPSIS...STEINBUGL NEAR TERM...DANGELO/STEINBUGL SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
724 AM EST TUE DEC 10 2013 .SYNOPSIS... ANOTHER WINTER WEATHER SYSTEM WILL BRING LIGHT TO MODERATE SNOWFALL TO PORTIONS OF CENTRAL AND SOUTHEASTERN PENNSYLVANIA TODAY. A VERY COLD AND BRISK WEST TO NORTHWEST FLOW WILL DEVELOP IN THE WAKE OF THIS SYSTEM...AND BRING MUCH COLDER AIR WITH BELOW NORMAL TEMPERATURES GRIPPING THE REGION THROUGH MID-TO-LATE WEEK. MODERATE TO LOCALLY HEAVY LAKE EFFECT SNOWS ARE ALSO FORECAST IN PERENNIAL SNOWBELT ACROSS THE NORTHWEST MOUNTAINS INTO THE SECOND HALF OF THE WEEK. ELSEWHERE...IT WILL BE GENERALLY COLD AND DRY. THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME WITH ANOTHER STORM SYSTEM LIKELY AFFECTING THE AREA OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DESPITE A LACK OF -SN BEING REPORTED IN THE SFC OBS...A QUICK GLANCE AT AREA WEBCAMS SHOWS SNOW IS REACHING THE GROUND IN SRN PA. EMBEDDED WITHIN THE BASE OF A PROGRESSIVE 500MB TROUGH...FAST- MOVG SHORTWAVE ENERGY AND STG HEIGHT FALLS /APPROACHING -200M IN 12HR/ WILL RACE EWD ACROSS THE UPPER OH VLY EARLY THIS MORNING AND MOVE THROUGH CENTRAL PA BTWN 15-21Z. DOWNSTREAM WARM AIR/MSTR ADVECTION INTERACTING WITH STRONG DIVERGENCE ALOFT ALONG THE RIGHT-ENTRANCE REGION OF A POWERFUL 175KT UPPER JET STREAK WILL CONTINUE TO ALLOW FOR A RAPID NEWD EXPANSION OF LGT-MOD SNOW QUICKLY SPREADING ACROSS SOUTH-CENTRAL AND SERN PA EARLY THIS MORNING. A CONSENSUS OF SHORT-RANGE HIRES MODELS SHOWS THE PERIOD OF MOST INTENSE SNOWS OCCURRING FROM MID-LATE MORNING BEFORE SNOW QUICKLY TAPERS OFF FROM W-E BY MID TO LATE AFTN. THE RAPID PROGRESSION OF THIS SYSTEM SHOULD LIMIT WIDESPREAD HEAVY AMTS WITH SNFL TOTALS GENERALLY IN THE 1-3/2-4" RANGE. HOWEVER...LOCALLY HEAVIER AMTS ARE POSSIBLE ESPECIALLY ALONG/S OF I-81 WHERE ENHANCED LOW-MID LVL FGEN AND MESO BANDING MAY SUPPORT A NARROW SWATH OF 4-6". THE LATEST RUC ALONG WITH THE HIRES WRF/NMM SUGGEST THE GREATEST POTENTIAL FOR HEAVY SNOW BANDING AND SNFL RATES BTWN 0.5-1" PER HOUR IS ALONG/S OF RT 30...WHERE THE FINAL NDFD SNFL GRAPHICS SHOW STORM TOTALS OF 3-5". THE ONLY CHANGE TO THE WW ADVY WAS TO BREAKOUT THE LWR SUSQ COUNTIES TO HIGHLIGHT EXPECTED HIER AMTS. THE MESO MODELS SHOW THE BULK OF THE ACCUM SNOW ENDING OVER THE LAURELS AND CNTRL MTNS BY 18Z...AND A FEW HOURS LATER IN THE MID- LWR SUSQ. INC WEST WINDS AND FALLING TEMPS WILL DROP WIND CHILLS SINGLE DIGITS AND LOW TEENS ACRS THE WRN ALLEGHENIES BY DARK. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... IN THE WAKE OF THE FAST-MOVING WINTER SYSTEM...A VIGOROUS CYCLONIC/NW FLOW PATTERN WILL GRIP THE REGION WITH BELOW NORMAL TEMPS AND LAKE EFFECT SNOWS THROUGH THE END OF THE WEEK. A REINFORCING SHOT OF COLD AIR FOLLOWING THE PASSAGE OF A NRN CLIPPER ON WED WILL HELP SUPPORT PERSISTENT...MAINLY W-E ORIENTED LES BANDS OVER THE PERENNIAL NW SNOWBELT IN NRN WARREN/MCKEAN COS WITH ACCUMS IN EXCESS OF 6" POSSIBLE BY THE END OF THE PD. OTHER THAN THE LES SNOW IN THE NW MTNS...MUCH OF THE REMAINDER OF THE AREA WILL BE COLD AND DRY. A CONSENSUS OF ALL MAX TEMP GUIDANCE SHOWS DAYTIME DEPARTURES OF -20F ACROSS MUCH OF THE AREA THU. WIND CHILLS WILL BE VERY COLD ESPECIALLY AT NIGHT AND IN THE EARLY MORNING WITH VALUES IN THE SINGLE DIGITS EITHER SIDE OF ZERO. HIGHLIGHTED THE WIND CHILLS IN THE HWO. THE GFS/ECMWF EVENTUALLY SHOW THE LAKE EFFECT WINDING DOWN AS HIGH PRESSURE ARRIVES IN THE MID-ATLC ON FRIDAY. && .LONG TERM /SATURDAY THROUGH MONDAY/... THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME BY THE WEEKEND...AS THE ENERGETIC SPLIT FLOW UPSTREAM MERGES OVER THE CENTRAL STATES...ALLOWING LOW PRESSURE TO DEVELOP IN THE LWR MS REGION AND TRACK NEWD INTO THE MID-ATLC/NORTHEAST STATES. WHILE THERE IS REASONABLE CONVERGENCE OF SOLUTIONS ON A STORM SYSTEM...THE DETAILS WILL NEED SORTING-OUT AT SHORTER RANGES TO DETERMINE SENSIBLE WX IMPACTS SUCH AS TIMING AND PTYPES. AT FIRST GLANCE...THE SET-UP IS SOMEWHAT SIMILAR TO THIS PAST SUNDAY`S SYSTEM WITH MIXED PRECIP AGAIN A CONCERN. THE COLD AIR PRECEDING THE NEW SYSTEM SHOULD BE MORE ROBUST WHICH SUGGESTS AN INCREASED CHANCE FOR FROZEN/FREEZING PTYPES. INCREASED POPS AROUND DAY 5 WITH REASONABLE MODEL AGREEMENT HOWEVER CONFIDENCE IN TIMING IS BELOW AVG GIVEN DIFFS IN THE OPRN GFS/EC AND THEIR RESPECTIVE ENSEMBLE MEANS. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... SNOW HAS BEGUN TO FALL ACROSS SOUTHEASTERN PA...WITH LIFR CONDITIONS AT MDT AND LNS. THESE CIGS AND VSBYS SHOULD CONTINUE THROUGH THE MORNING...TAPERING OFF BETWEEN 16 TO 18Z. THIS IS DUE TO A FAST-MOVING LOW PRESSURE SYSTEM THAT WILL SPREAD A PERIOD OF SNOW ACROSS MAINLY SOUTHERN PA UNTIL 18Z. LIGHTER SNOW WILL FALL FURTHER NORTH...WITH ONE TO THREE ACCUMULATIONS POSSIBLE. MVFR CIGS AND VSBYS REMAIN POSSIBLE THROUGHOUT THE REST OF THE TAF SITES THROUGH THIS TIMEFRAME. AFTER 18Z EXPECT CONDITIONS TO IMPROVE...WITH VFR DOMINATING CONDITIONS AFTER 22Z. THE ONLY CAVEAT WILL BE BFD WHERE THERE SHOULD BE A DROP IN CIGS AND VSBYS TO MVFR/IFR OVERNIGHT TONIGHT DUE TO NW FLOW AND LAKE ENHANCED SHOWERS. OUTLOOK... WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS. THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS. FRI...NO SIG WX EXPECTED. SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR PAZ024>028-033>036-049>053-056>059-063>066. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
551 AM EST TUE DEC 10 2013 .SYNOPSIS... ANOTHER WINTER WEATHER SYSTEM WILL BRING LIGHT TO MODERATE SNOWFALL TO PORTIONS OF CENTRAL AND SOUTHEASTERN PENNSYLVANIA TODAY. A VERY COLD AND BRISK WEST TO NORTHWEST FLOW WILL DEVELOP IN THE WAKE OF THIS SYSTEM...AND BRING MUCH COLDER AIR WITH BELOW NORMAL TEMPERATURES GRIPPING THE REGION THROUGH MID-TO-LATE WEEK. MODERATE TO LOCALLY HEAVY LAKE EFFECT SNOWS ARE ALSO FORECAST IN PERENNIAL SNOWBELT ACROSS THE NORTHWEST MOUNTAINS INTO THE SECOND HALF OF THE WEEK. ELSEWHERE...IT WILL BE GENERALLY COLD AND DRY. THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME WITH ANOTHER STORM SYSTEM LIKELY AFFECTING THE AREA OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DESPITE A LACK OF -SN BEING REPORTED IN THE SFC OBS...A QUICK GLANCE AT AREA WEBCAMS SHOWS SNOW IS REACHING THE GROUND IN SRN PA. EMBEDDED WITHIN THE BASE OF A PROGRESSIVE 500MB TROUGH...FAST- MOVG SHORTWAVE ENERGY AND STG HEIGHT FALLS /APPROACHING -200M IN 12HR/ WILL RACE EWD ACROSS THE UPPER OH VLY EARLY THIS MORNING AND MOVE THROUGH CENTRAL PA BTWN 15-21Z. DOWNSTREAM WARM AIR/MSTR ADVECTION INTERACTING WITH STRONG DIVERGENCE ALOFT ALONG THE RIGHT-ENTRANCE REGION OF A POWERFUL 175KT UPPER JET STREAK WILL CONTINUE TO ALLOW FOR A RAPID NEWD EXPANSION OF LGT-MOD SNOW QUICKLY SPREADING ACROSS SOUTH-CENTRAL AND SERN PA EARLY THIS MORNING. A CONSENSUS OF SHORT-RANGE HIRES MODELS SHOWS THE PERIOD OF MOST INTENSE SNOWS OCCURRING FROM MID-LATE MORNING BEFORE SNOW QUICKLY TAPERS OFF FROM W-E BY MID TO LATE AFTN. THE RAPID PROGRESSION OF THIS SYSTEM SHOULD LIMIT WIDESPREAD HEAVY AMTS WITH SNFL TOTALS GENERALLY IN THE 1-3/2-4" RANGE. HOWEVER...LOCALLY HEAVIER AMTS ARE POSSIBLE ESPECIALLY ALONG/S OF I-81 WHERE ENHANCED LOW-MID LVL FGEN AND MESO BANDING MAY SUPPORT A NARROW SWATH OF 4-6". THE LATEST RUC ALONG WITH THE HIRES WRF/NMM SUGGEST THE GREATEST POTENTIAL FOR HEAVY SNOW BANDING AND SNFL RATES BTWN 0.5-1" PER HOUR IS ALONG/S OF RT 30...WHERE THE FINAL NDFD SNFL GRAPHICS SHOW STORM TOTALS OF 3-5". THE ONLY CHANGE TO THE WW ADVY WAS TO BREAKOUT THE LWR SUSQ COUNTIES TO HIGHLIGHT EXPECTED HIER AMTS. THE MESO MODELS SHOW THE BULK OF THE ACCUM SNOW ENDING OVER THE LAURELS AND CNTRL MTNS BY 18Z...AND A FEW HOURS LATER IN THE MID- LWR SUSQ. INC WEST WINDS AND FALLING TEMPS WILL DROP WIND CHILLS SINGLE DIGITS AND LOW TEENS ACRS THE WRN ALLEGHENIES BY DARK. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... IN THE WAKE OF THE FAST-MOVING WINTER SYSTEM...A VIGOROUS CYCLONIC/NW FLOW PATTERN WILL GRIP THE REGION WITH BELOW NORMAL TEMPS AND LAKE EFFECT SNOWS THROUGH THE END OF THE WEEK. A REINFORCING SHOT OF COLD AIR FOLLOWING THE PASSAGE OF A NRN CLIPPER ON WED WILL HELP SUPPORT PERSISTENT...MAINLY W-E ORIENTED LES BANDS OVER THE PERENNIAL NW SNOWBELT IN NRN WARREN/MCKEAN COS WITH ACCUMS IN EXCESS OF 6" POSSIBLE BY THE END OF THE PD. OTHER THAN THE LES SNOW IN THE NW MTNS...MUCH OF THE REMAINDER OF THE AREA WILL BE COLD AND DRY. A CONSENSUS OF ALL MAX TEMP GUIDANCE SHOWS DAYTIME DEPARTURES OF -20F ACROSS MUCH OF THE AREA THU. WIND CHILLS WILL BE VERY COLD ESPECIALLY AT NIGHT AND IN THE EARLY MORNING WITH VALUES IN THE SINGLE DIGITS EITHER SIDE OF ZERO. HIGHLIGHTED THE WIND CHILLS IN THE HWO. THE GFS/ECMWF EVENTUALLY SHOW THE LAKE EFFECT WINDING DOWN AS HIGH PRESSURE ARRIVES IN THE MID-ATLC ON FRIDAY. && .LONG TERM /SATURDAY THROUGH MONDAY/... THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME BY THE WEEKEND...AS THE ENERGETIC SPLIT FLOW UPSTREAM MERGES OVER THE CENTRAL STATES...ALLOWING LOW PRESSURE TO DEVELOP IN THE LWR MS REGION AND TRACK NEWD INTO THE MID-ATLC/NORTHEAST STATES. WHILE THERE IS REASONABLE CONVERGENCE OF SOLUTIONS ON A STORM SYSTEM...THE DETAILS WILL NEED SORTING-OUT AT SHORTER RANGES TO DETERMINE SENSIBLE WX IMPACTS SUCH AS TIMING AND PTYPES. AT FIRST GLANCE...THE SET-UP IS SOMEWHAT SIMILAR TO THIS PAST SUNDAY`S SYSTEM WITH MIXED PRECIP AGAIN A CONCERN. THE COLD AIR PRECEDING THE NEW SYSTEM SHOULD BE MORE ROBUST WHICH SUGGESTS AN INCREASED CHANCE FOR FROZEN/FREEZING PTYPES. INCREASED POPS AROUND DAY 5 WITH REASONABLE MODEL AGREEMENT HOWEVER CONFIDENCE IN TIMING IS BELOW AVG GIVEN DIFFS IN THE OPRN GFS/EC AND THEIR RESPECTIVE ENSEMBLE MEANS. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... LOW CIGS/FOG PERSISTING LATE THIS EVENING ACROSS SOUTHEAST PA BENEATH TEMPERATURE INVERSION WITH LGT WINDS. LATEST MDL DATA SUGGESTS INVERSION AND ASSOC LOW CIGS/FOG MAY FINALLY BE SCOURED OUT BETWEEN 06Z AND 07Z AT KMDT. HOWEVER...OUTLOOK NOT AS FAVORABLE ANY FURTHER SE...WITH KLNS LIKELY REMAINING SOCKED IN THROUGH 09Z. ELSEWHERE...RESIDUAL LOW LVL MOISTURE FORCED TO ASCEND THE ALLEGHENY MTNS HAS ALLOWED STRATOCU ACROSS THE W MTNS WITH MVFR CIGS AT JST/KBFD/KAOO/KUNV. SEE LITTLE CHANGE IS THESE CONDS FOR MUCH OF THE NIGHT...ALTHOUGH DOWNSLOPING FLOW EAST OF THE MTNS SHOULD MAINTAIN VFR CONDS AT KIPT. A FAST-MOVING LOW PRESSURE SYSTEM WILL TRACK SOUTH OF PA TUESDAY MORNING...SPREADING A PERIOD OF SNOW ACROSS MAINLY SOUTHERN PA BTWN 10Z-18Z. IFR VSBYS APPEAR LIKELY DURING LATE AM/EARLY AFTN AT KMDT AND KLNS. LIGHTER SNOW WILL FALL FURTHER NORTH. HOWEVER...A BRIEF DIP TO IFR VSBYS IS POSSIBLE ELSEWHERE TUE AM. IMPROVING CONDS ARE EXPECTED BY TUE AFTN AS THE LOW PRES SYSTEM PASSES OFF THE MID ATLANTIC COAST. OUTLOOK... WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS. THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS. FRI...NO SIG WX EXPECTED. SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR PAZ024>028-033>036-049>053-056>059-063>066. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...STEINBUGL AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
543 AM CST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CST TUE DEC 10 2013 CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER THE EAST PACIFIC...TROUGHING OVER CENTRAL AND EASTERN CANADA AND SOUTHWARD INTO THE UPPER MIDWEST. WITHIN THIS TROUGH...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST MINNESOTA WHILE ANOTHER SHORTWAVE COULD BE SEEN UPSTREAM IN CENTRAL ALBERTA. THE STRONG DPVA FORCING AHEAD OF THE POTENT SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND SOME MOISTURE HAS HELPED SPREAD CLOUDS ACROSS THE FORECAST AREA. IN ADDITION...LIGHT SNOW WAS MOVING ACROSS THE FORECAST AREA. ALSO ACCOMPANYING THE POTENT SHORTWAVE WAS A RELATIVELY DEEP SURFACE LOW CENTERED NEAR MINNEAPOLIS. THE COMBINATION OF THE CLOUDS AND STRENGTHENING SOUTHERLY WINDS AHEAD OF THE LOW HAVE HELPED TO BRING TEMPERATURES UP THROUGH THE NIGHT. MOST WIND CHILLS ARE ABOVE ADVISORY CRITERIA OF -20F...THUS WE WERE ABLE TO CANCEL TAYLOR/CLARK EARLY. SIMILARLY...ON THE BACK SIDE OF THE SURFACE LOW WHERE PRESSURES ARE RISING RAPIDLY...STRONG NORTHWEST WINDS ARE OCCURRING. THESE ARE ADVECTING IN A BRIEF SURGE OF ARCTIC AIR CHARACTERIZED BY 850MB TEMPS OF -20C PER RAP ANALYSIS. SKIES BEGIN TO CLEAR OUT QUICKLY TOO ON THE BACK SIDE OF THE LOW. THE POTENT SHORTWAVE IN MINNESOTA REMAINS PROGGED TO FLY THROUGH THE FORECAST AREA THIS MORNING...SUCH THAT IT IS ALREADY IN LOWER MICHIGAN BY 18Z. WHAT THIS MEANS IS WE SHOULD HAVE A BRIEF PERIOD OF SNOW FOR THE EARLY MORNING HOURS...AFFECTING THE MORNING COMMUTE. ONCE THE WAVE PASSES...EXPECTING WINDS TO CRANK UP OUT OF THE WEST AS PRESSURES RISE RAPIDLY. GUSTS ARE LIKELY TO RANGE 25-35 KT WITH THE PRESSURE RISE COMING IN...HIGHEST IN SOUTHEAST MN. SOME BLOWING AND DRIFTING OF ALL THE RECENT SNOW IS LIKELY. IT APPEARS BRISK WINDS WILL PERSIST UNTIL LATE IN THE DAY WHEN A SURFACE RIDGE BUILDS IN. THE BRISK WINDS WILL ALSO BRING IN COLDER AIR...CAUSING TEMPS TO FALL...DESPITE INCREASING SUNSHINE. THE CLEARING THIS AFTERNOON LOOKS TO BE SHORT-LIVED...HOWEVER. THE NEXT SHORTWAVE OVER ALBERTA IS PROGGED TO DROP DOWN INTO WESTERN IOWA BY 12Z WEDNESDAY. AS THIS OCCURS...A MID-LEVEL FRONTOGENESIS BAND WILL SET UP AHEAD OF IT. 10.00Z GFS/NAM/ECMWF/CANADIAN TRACK THIS BAND FROM SOUTH DAKOTA THIS AFTERNOON INTO FAR SOUTHERN MN AND NORTHERN IA THIS EVENING...AND FINALLY INTO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS OVERNIGHT. GIVEN GOOD MODEL CONSENSUS HAVE RAISED PRECIPITATION CHANCES UP TOWARDS 100 SOUTH OF A LINE FROM AUSTIN MN TO RICHLAND CENTER WI. MOISTURE IS LIMITED...ON THE ORDER OF 1 G/KG...BUT THE STRONG FRONTOGENESIS SHOULD BE ABLE TO SQUEEZE OUT A TENTH OF LIQUID. WITH SNOW TO WATER RATIOS ON THE ORDER OF 15-20 TO 1...THIS WILL YIELD A QUICK 1 TO 2 INCHES OF SNOWFALL. FINALLY...IN THE WAKE OF THAT FRONTOGENESIS BAND...THAT SHORTWAVE TROUGH LOOKS TO BRING DOWN ANOTHER SURGE OF ARCTIC AIR WITH IT. 850MB TEMPS AFTER BRIEFLY CLIMBING TO -14 TO -18C AHEAD OF THE BAND...FALL TO -18 TO -22C BY 12Z WEDNESDAY. A TIGHTENING SURFACE PRESSURE GRADIENT SHOULD YIELD INCREASING NORTH WINDS...ADDING A WIND CHILL FACTOR. WIND CHILL ADVISORIES HAVE BEEN ISSUED...STARTING TAYLOR/CLARK AT 06Z AND THEN SOUTHEAST MN AND OTHER WI COUNTIES NORTH OF I-90 AT 10Z. THE WIND ON TOP OF THE NEW SNOW MAY PRODUCE SOME BLOWING AND DRIFTING ACROSS NORTHEAST IA TOO LATE IN THE NIGHT. CLEARING ALSO LOOKS TO ACCOMPANY THE CHILLY AIR. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 343 AM CST TUE DEC 10 2013 PLAN ON A COLD WEDNESDAY. ARCTIC AIR IS FORECAST TO GET DRAGGED INTO THE FORECAST AREA AS THE SHORTWAVE TROUGH OVER WESTERN IA HEADS EAST. TEMPS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...OR EVEN TO ZERO ACROSS TAYLOR/CLARK COUNTIES. ON TOP OF THE COLD...A DECENT PRESSURE GRADIENT IN PLACE SHOULD KEEP A NORTHWEST BREEZE GOING...RESULTING IN WIND CHILLS FROM THE -10 TO -30F RANGE. THESE COLD WIND CHILLS LOOK TO PERSIST INTO WEDNESDAY EVENING BEFORE WINDS TURN SOUTHWEST ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS PASSAGE. TEMPERATURES ARE FORECAST TO CLIMB AFTER MIDNIGHT IN RESPONSE TO THIS SOUTHWEST WIND...AS WELL AS INCREASING MID/HIGH CLOUDS. THESE CLOUDS ARE ASSOCIATED WITH ISENTROPIC LIFT WELL DOWNSTREAM OF A SHORTWAVE IN MONTANA. ONE QUESTION MARK IS IF ANY SNOW CAN FORM FROM THIS ISENTROPIC LIFT. MODELS HAVE BEEN GOING BACK AND FORTH ON THIS...WITH THE 10.00Z ECMWF AND GFS NOW BASICALLY DRY FOR WEDNESDAY NIGHT AND THURSDAY...WHEREAS THE 10.00Z CANADIAN MAINTAINS SOME LIGHT PRECIP OVER THE AREA BETWEEN 06-12Z THU. FOR NOW KEPT A 20 PERCENT CHANCE GOING BETWEEN 06-12Z THURSDAY OVER THE NORTHEAST PORTION OF THE AREA WITH DRY CONDITIONS BEFORE AND AFTER. WITH A WARM ADVECTION PATTERN IN PLACE THURSDAY...TEMPERATURES EXPECTED TO BE MUCH WARMER...ON THE ORDER OF 15-20 DEGREES. FROM THURSDAY NIGHT INTO FRIDAY...THE UPPER FLOW IS PROGGED TO BECOME MORE ZONAL OVER THE NORTHERN U.S.. WHAT THIS DOES IS ALLOWS A FRONTOGENESIS ZONE TO SET UP FROM THE DAKOTAS INTO WISCONSIN. THIS FRONTOGENESIS FORCING MAY RESULT IN SOME LIGHT SNOW THE ENTIRE TIME...WITH THE BEST CHANCES STAYING MAINLY NORTH OF THE FORECAST AREA. DID HONOR SOME 20 PERCENT CHANCES NORTH OF I-94 THURSDAY NIGHT PER MODEL CONSENSUS. ALSO ON FRIDAY...A SOUTHERN STREAM SHORTWAVE TROUGH IS SUGGESTED TO MOVE INTO THE CENTRAL PLAINS. FRONTOGENESIS DOWNSTREAM OF THIS SHORTWAVE TROUGH MAY SPREAD LIGHT PRECIP INTO SOUTHERN SECTIONS FOR THE FORECAST AREA. FOR NOW KEPT THIS PRECIP OUT...BUT SOMETHING TO MONITOR. THE SOUTHERN STREAM SYSTEM WILL NEED EVEN MORE MONITORING AS WE HEAD INTO FRIDAY NIGHT AND SATURDAY. MODELS ARE SUGGESTING AN INVERTED SURFACE TROUGH ASSOCIATED WITH THIS SHORTWAVE MOVING THROUGH THE FORECAST AREA. INVERTED TROUGHS ARE KNOWN TO BRING SNOW...SO PRECIPITATION CHANCES HAVE BEEN RAISED FOR FRIDAY NIGHT AND SATURDAY. IT SHOULD BE NOTED...THOUGH...THAT THE BULK OF THE ACCUMULATING SNOW LOOKS TO STAY SOUTHEAST OF THE AREA. ANOTHER BRIEF COOL DOWN...BUT NOT AS COLD AS SEEN RECENTLY...IS SUGGESTED FOR SUNDAY WITH DRY CONDITIONS AS HIGH PRESSURE MOVES THROUGH. LIGHT WARM ADVECTION SNOWS ARE PROGGED FOR MONDAY AS ANOTHER NORTHERN STREAM SHORTWAVE TROUGH DROPS DOWN TOWARDS THE UPPER MIDWEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 543 AM CST TUE DEC 10 2013 IFR/MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES THIS MORNING WITH VFR CONDITIONS EXPECTED BY THE LATE MORNING HOURS. A FAST MOVING AND COMPACT DISTURBANCE WILL MOVE ACROSS THE TAF SITES EARLY THIS MORNING. WEST/NORTHWEST WINDS WILL INCREASE TO 17 TO 25 KTS WITH GUSTS TO AROUND 33 KTS POSSIBLE. THIS WILL LEAD TO AREAS OF BLOWING SNOW...POSSIBLY REDUCING VISIBILITIES TO AROUND 4SM AT TIMES. A BRIEF PERIOD OF IFR VISIBILITIES ARE POSSIBLE IN THE BLOWING SNOW THIS MORNING AT KRST. SKIES WILL CLEAR BY THE MID TO LATE MORNING HOURS WITH VFR CONDITIONS EXPECTED THROUGH THE AFTERNOON. ANOTHER SYSTEM WILL MOVE ACROSS THE REGION TONIGHT BRINGING LIGHT SNOW AND IFR CONDITIONS TO THE TAF SITES. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR WIZ032>034-041>044. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST THURSDAY FOR WIZ017-029. MN...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR MNZ079- 086>088-094>096. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
341 PM MST TUE DEC 10 2013 .SHORT TERM...WINDS STILL QUITE GUSTY IN AND NEAR FOOTHILLS... BEGINNING TO SHOW SOME DECREASE AS PRESSURE GRADIENT FROM GJT TO DEN DECREASES AND WEAK LIFT FROM APPROACHING WAVE BEGINS TO OFFSET THE DOWNWARD MOTION. CROSS MOUNTAIN FLOW AVERAGED AROUND 50 KTS ACROSS THE NORTHERN FOOTHILLS FOR MUCH OF THE AFTERNOON...BASED ON THE RAP ALONG WITH THE PERSISTENT MOUNTAIN WAVE. THE PRESSURE GRADIENT FROM GJT TO DEN DID PEAK AT 15.16 MB AT 17Z. DID RECEIVE A GUST TO 83 MPH AT LYONS AT 115 PM...APPEARS THIS STRONG WIND GUST WAS CHANNELED ACROSS THIS AREA AND RATHER LOCALIZED. OTHER GUSTS ALONG THE FOOTHILLS NOT NEARLY THAT STRONG...GENERALLY AROUND 60 MPH. THE GUSTY DOWNSLOPE WINDS DID INCREASE TEMPERATURES ACROSS THE URBAN CORRIDOR. STILL THINKING THE WINDS WILL BE ON THE DECREASE BY THE EVENING ONCE THE AIRMASS STABILIZES AND MOUNTAIN WAVE WEAKENS. SHORT TERM MODELS SHOW THE GJT TO DEN PRESSURE GRADIENT DECREASING THROUGH THE EVENING... WITH THE CROSS MOUNTAIN FLOW DECREASING TO AROUND 40 KTS NEAR MOUNTAIN TOP. MAY STILL BE A BIT GUSTY IN AND NEAR THE FOOTHILLS. MOISTURE NOW SPREADING INTO NORTHERN MOUNTAINS AS THE MID LEVEL DISTURBANCE MOVES ACROSS WYOMING. WEAK MID LEVEL ASCENT AND OROGRAPHICS WITH NORTHWEST FLOW ALOFT ENOUGH TO KEEP A CHANCE OF LIGHT SNOW FOR THE NORTHERN MOUNTAINS. SNOW CHANCES DECREASE ACROSS CENTRAL MOUNTAINS. LATEST MODEL QPF HAD DECREASED THE AMOUNT OF PRECIP AND THUS SNOW AMOUNTS. SO ANY ACCUMULATIONS TO BE AROUND AN INCH OR LESS... MAINLY ACROSS ZONE 31. ACROSS THE PLAINS...WEAK SURGE STILL EXPECTED TO MOVE INTO THE AREA AROUND MIDNIGHT...DROPPING TEMPERATURES BACK INTO THE SINGLE DIGITS DESPITE THE NICE WARMUP THIS AFTERNOON. WINDS WILL BE WEAKENING DURING THE EVENING...AND MAY BECOME EASTERLY FOR A SHORT TIME BEFORE GOING TO DRAINAGE AROUND MIDNIGHT. CROSS SECTIONS DO NOT SHOW ANY LOW LEVEL MOISTURE SO DO NOT THINK FOG OR LOW STRATUS WILL DEVELOP. MAY BE SOME MID LEVEL CLOUD DURING THE EVENING. ON WEDNESDAY...THE NORTHWEST FLOW ALOFT WILL CONTINUE THOUGH NOT AS STRONG AS TODAY. NAM CROSS SECTIONS SHOWING CROSS MOUNTAIN FLOW AROUND 25-30 KTS. MAY SEE SOME GUSTS AROUND 40 MPH OVER THE MOUNTAINS AND HIGHER FOOTHILLS. ACROSS PLAINS...COOLER AIRMASS WILL BE IN PLACE...WITH HIGHS ONLY IN THE LOWER 30S. ACTUALLY ABOUT 10 TO 15 DEGREES COOLER ALONG THE URBAN CORRIDOR. AIRMASS WILL BE DRY WITH NO PRECIPITATION EXPECTED. JUST SOME HIGH LEVEL MOISTURE DURING THE AFTERNOON. .LONG TERM...THE FLOW ALOFT WILL REMAIN NORTHWESTERLY WEDNESDAY NIGHT WITH AN UPPER RIDGE TO THE NORTHWEST AND A WEAK TROUGH OFF THE SRN CA/BAJA COAST. THURSDAY INTO THURSDAY NIGHT...WEAK UPWARD ASCENT WILL DEVELOP...AS THE CLOSED UPPER LOW SHIFT TO THE NORTH AND EAST. THE MDLS EVENTUALLY MOVE THIS SYSTEM ACROSS SRN CO/NRN NEW MX LATE THURSDAY NIGHT INTO FRIDAY...WITH A WEAK SECONDARY SYSTEM DROPPING FM THE PAC NORTHWEST AND PASSING ACROSS WRN AND SRN CO LATE FRIDAY INTO FRIDAY NIGHT. SINCE BOTH OF THESE SYSTEMS ARE WEAK AND GENERALLY PASSING TO THE WEST AND SOUTH OF THE CWFA...WL GO WITH NO MORE THAN A CHANCE OF SNOW IN THE HIGH COUNTRY. THE BEST CHANCE OF SNOW IN THE NRN MOUNTAINS APPEARS TO BE FRIDAY NIGHT...WITH THE PASSAGE OF THE SECOND SYSTEM. ACROSS THE PLAINS...IT WILL REMAIN DRY THROUGH THE PERIOD. IT WILL WARM INTO THURSDAY...WITH SLIGHTLY COOLER TEMPERATURES (BUT STILL NEAR NORMAL) ON FRIDAY AND SATURDAY...WITH TEMPERATURES EXPECTED WARM UP AGAIN SUNDAY AND MONDAY. A LEE SIDE SURFACE TROUGH WILL DEVELOP OVER EASTERN CO THURSDAY AFTN...WITH A WEAK FROPA FRIDAY AFTN. SUNDAY INTO MONDAY...A BROAD UPPER RIDGE OVER THE WEST COAST WILL PRODUCE AND DRY AND SUBSIDENT NORTHWESTERLY FLOW ALOFT OVER CO. && .AVIATION...WINDS TRENDING MORE NORTHWEST...WITH SOME DECREASE IN SPEEDS. GUSTS STILL AROUND 30 KTS AT KBJC WITH A FEW GUSTS AROUND 20 KTS AT KDEN. GRADIENT EXPECTED TO WEAKEN THIS EVENING... SHOULD SEE WINDS DECREASE AS A RESULT. A WEAK SURGE WILL BE MOVING IN FROM THE NORTH AROUND MIDNIGHT. WINDS MAY GO NORTHEAST AROUND 03Z AND EAST TO SOUTHEAST BY 06Z AS SHOWN BY THE LATEST MODELS. BUT WILL BE FIGHTING THE WEAKENING WEST TO EAST GRADIENT. CURRENT THINKING IS THAT THE SOUTHERLY DRAINAGE FLOW WILL PREVAIL BY 03Z AND CONTINUE THROUGH THE MORNING HOURS WEDNESDAY. BY 18Z WINDS TO BECOME SHIFT TO THE SOUTHEAST...SPEEDS TO STAY BELOW 8 KTS. VFR TO CONTINUE WITH UNLIMITED CEILINGS. LOWER AIRMASS WILL BE DRY SO NOT EXPECTING LOW CLOUDS OR FOG OVERNIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....COOPER AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
123 PM MST TUE DEC 10 2013 .UPDATE... && .SHORT TERM...CHINOOK WINDS HAVE WARMED TEMPERATURES ACROSS THE URBAN CORRIDOR AND ADJACENT PLAINS INTO THE 40S. ALSO...WINDS STILL GUSTY THOUGH DECREASING TRENDS STILL LOOKS REASONABLE BY THIS EVENING. TEMPERATURE AND WIND GRIDS UPDATED TO REFLECT CURRENT CONDITIONS. .PREV DISCUSSION... /ISSUED 955 AM MST TUE DEC 10 2013/ UPDATE... SHORT TERM...BRISK NORTHWEST FLOW ALOFT STILL PRODUCING AMPLIFIED MOUNTAIN WAVE OVER NORTHERN COLORADO. WINDS FAIRLY GUSTY OVER MOUNTAIN RIDGES AND EASTERN SLOPES WITH SOME GUSTS AROUND 50 MPH OBSERVED ALONG THE FOOTHILLS OF NORTHERN JEFFERSON AND SOUTHERN BOULDER COUNTIES. SOME SIGNS OF THE MOUNTAIN WAVE ON THE DECREASE WITH WEAKENING MOUNTAIN TOP INVERSION...DUE TO WEAK ASCENT BEGINNING TO MOVE INTO STATE AHEAD OF A MID LEVEL DISTURBANCE. SHOULD CONTINUE TO SEE SOME DECREASE IN WINDS THROUGH THE AFTERNOON...LATEST RAP INDICATING CROSS MOUNTAIN FLOW DECREASING. THIS TREND NOTED IN LATEST GRIDS...LOOKS REASONABLE. DID INCLUDE LOCAL BLOWING SNOW EARLY THIS AFTERNOON OVER THE HIGHER FOOTHILLS. ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER DUE TO CURRENT TRENDS. REST OF FORECAST SEEMS REASONABLE. SOME INCREASE IN MOISTURE ACROSS MOUNTAINS LATER TODAY WITH A CHANCE OF SNOW NORTHERN MOUNTAINS BY THIS EVENING. SNOW AMOUNTS TO BE LESS THAN 2 INCHES. && .AVIATION...WESTERLY WINDS SPREADING ACROSS AREA...WITH GUSTS TO 35 KTS AT KBJC. WINDS LESS FURTHER EAST...THOUGH SOME GUSTS AROUND 20 KTS SPREADING ACROSS KDEN. WINDS WILL BE DECREASING BY 21Z...TRENDING A BIT MORE NORTHWEST AT KDEN AND KAPA. DRAINAGE WINDS THEN EXPECTED BY 02Z. WILL CONTINUE CURRENT TAF TRENDS FOR THE UPCOMING ISSUANCE. VFR CONDITIONS TO PREVAIL WITH UNLIMITED CEILINGS. .PREV DISCUSSION... /ISSUED 359 AM MST TUE DEC 10 2013/ SHORT TERM...NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER COLORADO TODAY AND TONIGHT AS A STRONG UPPER RIDGE AXIS REMAINS ANCHORED JUST OFFSHORE FROM THE PACIFIC NORTHWEST. THE AIRMASS OVER THE FORECAST AREA IS STARTING OUT VERY DRY...BUT MID-LEVEL MOISTURE WILL BE INCREASING OVER THE MOUNTAINS BY THIS AFTERNOON. SOME PARTS OF NORTHWEST COLORADO ARE ALREADY SEEING A MID-LEVEL CLOUD DECK MOVE OVERHEAD AT THE PRESENT TIME. AS THE MOISTURE INCREASES...THE CHANCE OF SNOW WILL RETURN TO THE MOUNTAIN AREAS OF NORTH-CENTRAL COLORADO. MODEL QPF FIELDS ONLY SHOW LIGHT AMOUNTS OF SNOW FROM THIS SHOT OF MOISTURE. IT ALSO APPEARS THAT IT WILL ONLY SNOW FOR ABOUT 6-12 HOURS. SNOW ACCUMULATIONS SHOULD BE LESS THAN 1 OR 2 INCHES. AHEAD OF THE APPROACHING MOISTURE...GUSTY WINDS HAVE BEEN BLOWING OVER THE MOUNTAIN RIDGES AND EASTERN SLOPES. GUSTS UP TO 60 MPH HAVE BEEN OBSERVED AT A FEW LOCATIONS. HOWEVER...THE WINDS HAVE BEEN QUITE LOCALIZED AND NOT STRONG ENOUGH TO WARRANT ANY HIGHLIGHT. THE FORECAST WILL MENTION PATCHY BLOWING SNOW BECAUSE OF THE WINDS. THE AMPLIFIED MOUNTAIN WAVE THAT IS DRIVING THE GUSTY WINDS LOOKS LIKE IT WILL BEGIN WEAKENING AFTER 11 AM WITH GRADUALLY DIMINISHING WINDS THROUGH THE AFTERNOON HOURS. THE ARRIVAL OF INCREASING MOISTURE DURING THE AFTERNOON MAY ALSO HELP ALTER THE MOUNTAIN WAVE AND DECREASE THE WINDS SOONER. THE OTHER FEATURE OF THE FORECAST IS TEMPERATURES ON THE PLAINS CLIMBING ABOVE THE FREEZING MARK FOR THE FIRST TIME IN A WEEK...IF ONLY BY A FEW DEGREES AND PRIMARILY SOUTH OF I-76. TEMPERATURES TO THE NORTH OF I-76 ARE ONLY EXPECTED TO MAKE IT TO ABOUT 30 DEGREES. TEMPERATURES TONIGHT WILL DROP BACK TO THE SINGLE DIGITS AS A WEAK SURGE OF COOLER AIR MOVES IN FROM THE NORTH. LONG TERM...NW FLOW ALOFT WILL BE OVER THE AREA ON WED AND THEN BECOME MORE WLY BY THU. CROSS-SECTIONS SHOW ANY MOISTURE WILL BE ABV 500 MB SO WILL KEEP A DRY FCST IN PLACE BOTH DAYS ALTHOUGH THERE MAYBE SOME WAVE CLOUDS FROM TIME TO TIME. TEMPS WILL CONTINUE TO MODERATE SLOWLY WITH READINGS OVER NERN CO RANGING FROM THE MID 20S TO LOWER 30S ACROSS THE PLAINS WHILE AREAS AROUND DENVER RISE INTO THE MID TO UPPER 30S. BY THU READINGS SHOULD RISE BACK INTO THE LOWER TO MID 40S OVER MOST OF NERN CO. WINDS WILL CONTINUE GUSTY IN THE MTNS AND FOOTHILLS BOTH DAYS BUT SPEEDS SHOULD STAY BLO HIGH WIND CRITERIA. BY FRI A WK UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA IN NW FLOW ALOFT. CROSS-SECTIONS SHOW ENOUGH MOISTURE FOR A CHC OF SNOW SHOWERS IN THE MTNS. OVER NERN CO A COOL FNT WILL AFFECT THE NERN PLAINS BY AFTN AND THEN BACKDOOR INTO THE FRONT RANGE BY EARLY FRI EVENING. THERE COULD BE A SLIGHT CHC OF SNOW SHOWERS OVER NERN CORNER FRI EVENING AS THE WK UPPER LEVEL TROUGH MOVES ACROSS. AS FOR HIGHS WILL KEEP READINGS IN THE LOWER TO MID 40S OVER NERN CO HOWEVER IF FNT COMES IN FASTER THEN HIGHS COULD END UP BEING COOLER. FOR SAT AND SUN BRISK NW FLOW ALOFT WILL BE OVER THE AREA WITH SOME MOISTURE AFFECTING THE MTNS. APPEARS A WK DISTURBANCE COULD LEAD TO A BETTER CHC OF SNOW SHOWERS ON SUN. OVER NERN CO OUTSIDE OF SOME MID AND HIGH CLOUDS IT LOOKS DRY BOTH DAYS. HIGHS ON SAT MAY DROP BACK INTO THE UPPER 30S TO LOWER 40S OVER NERN CO BUT THEN REBOUND BACK INTO THE 40S ON SUN. BY MON LITTLE CHANGE WILL OCCUR AS NW FLOW ALOFT REMAINS OVER THE AREA. MOISTURE DECREASES ON MON IN THE MTNS SO WILL ONLY MENTION A SLIGHT CHC OF SNOW. OVER NERN CO IT WILL BE DRY WITH HIGHS RISING INTO THE MID 40S TO NEAR 50. AVIATION...CEILINGS AND VISIBILITIES WILL REMAIN UNRESTRICTED THROUGH TODAY AND TONIGHT WITH NO PRECIPITATION EXPECTED. PERIODS OF WEST WINDS...GUSTING TO 30-35 MPH...WILL CONTINUE THIS MORNING NEAR THE FOOTHILLS AND AS FAR EAST AS KBJC...BUT ARE NOT EXPECTED TO AFFECT KDEN OR KAPA. WINDS WILL BE DIMINISHING THROUGH THE AFTERNOON HOURS. TYPICAL DRAINAGE WINDS ARE EXPECTED OVERNIGHT TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RPK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
955 AM MST TUE DEC 10 2013 .UPDATE... && .SHORT TERM...BRISK NORTHWEST FLOW ALOFT STILL PRODUCING AMPLIFIED MOUNTAIN WAVE OVER NORTHERN COLORADO. WINDS FAIRLY GUSTY OVER MOUNTAIN RIDGES AND EASTERN SLOPES WITH SOME GUSTS AROUND 50 MPH OBSERVED ALONG THE FOOTHILLS OF NORTHERN JEFFERSON AND SOUTHERN BOULDER COUNTIES. SOME SIGNS OF THE MOUNTAIN WAVE ON THE DECREASE WITH WEAKENING MOUNTAIN TOP INVERSION...DUE TO WEAK ASCENT BEGINNING TO MOVE INTO STATE AHEAD OF A MID LEVEL DISTURBANCE. SHOULD CONTINUE TO SEE SOME DECREASE IN WINDS THROUGH THE AFTERNOON...LATEST RAP INDICATING CROSS MOUNTAIN FLOW DECREASING. THIS TREND NOTED IN LATEST GRIDS...LOOKS REASONABLE. DID INCLUDE LOCAL BLOWING SNOW EARLY THIS AFTERNOON OVER THE HIGHER FOOTHILLS. ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER DUE TO CURRENT TRENDS. REST OF FORECAST SEEMS REASONABLE. SOME INCREASE IN MOISTURE ACROSS MOUNTAINS LATER TODAY WITH A CHANCE OF SNOW NORTHERN MOUNTAINS BY THIS EVENING. SNOW AMOUNTS TO BE LESS THAN 2 INCHES. .AVIATION...WESTERLY WINDS SPREADING ACROSS AREA...WITH GUSTS TO 35 KTS AT KBJC. WINDS LESS FURTHER EAST...THOUGH SOME GUSTS AROUND 20 KTS SPREADING ACROSS KDEN. WINDS WILL BE DECREASING BY 21Z...TRENDING A BIT MORE NORTHWEST AT KDEN AND KAPA. DRAINAGE WINDS THEN EXPECTED BY 02Z. WILL CONTINUE CURRENT TAF TRENDS FOR THE UPCOMING ISSUANCE. VFR CONDITIONS TO PREVAIL WITH UNLIMITED CEILINGS. && .PREV DISCUSSION... /ISSUED 359 AM MST TUE DEC 10 2013/ SHORT TERM...NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER COLORADO TODAY AND TONIGHT AS A STRONG UPPER RIDGE AXIS REMAINS ANCHORED JUST OFFSHORE FROM THE PACIFIC NORTHWEST. THE AIRMASS OVER THE FORECAST AREA IS STARTING OUT VERY DRY...BUT MID-LEVEL MOISTURE WILL BE INCREASING OVER THE MOUNTAINS BY THIS AFTERNOON. SOME PARTS OF NORTHWEST COLORADO ARE ALREADY SEEING A MID-LEVEL CLOUD DECK MOVE OVERHEAD AT THE PRESENT TIME. AS THE MOISTURE INCREASES...THE CHANCE OF SNOW WILL RETURN TO THE MOUNTAIN AREAS OF NORTH-CENTRAL COLORADO. MODEL QPF FIELDS ONLY SHOW LIGHT AMOUNTS OF SNOW FROM THIS SHOT OF MOISTURE. IT ALSO APPEARS THAT IT WILL ONLY SNOW FOR ABOUT 6-12 HOURS. SNOW ACCUMULATIONS SHOULD BE LESS THAN 1 OR 2 INCHES. AHEAD OF THE APPROACHING MOISTURE...GUSTY WINDS HAVE BEEN BLOWING OVER THE MOUNTAIN RIDGES AND EASTERN SLOPES. GUSTS UP TO 60 MPH HAVE BEEN OBSERVED AT A FEW LOCATIONS. HOWEVER...THE WINDS HAVE BEEN QUITE LOCALIZED AND NOT STRONG ENOUGH TO WARRANT ANY HIGHLIGHT. THE FORECAST WILL MENTION PATCHY BLOWING SNOW BECAUSE OF THE WINDS. THE AMPLIFIED MOUNTAIN WAVE THAT IS DRIVING THE GUSTY WINDS LOOKS LIKE IT WILL BEGIN WEAKENING AFTER 11 AM WITH GRADUALLY DIMINISHING WINDS THROUGH THE AFTERNOON HOURS. THE ARRIVAL OF INCREASING MOISTURE DURING THE AFTERNOON MAY ALSO HELP ALTER THE MOUNTAIN WAVE AND DECREASE THE WINDS SOONER. THE OTHER FEATURE OF THE FORECAST IS TEMPERATURES ON THE PLAINS CLIMBING ABOVE THE FREEZING MARK FOR THE FIRST TIME IN A WEEK...IF ONLY BY A FEW DEGREES AND PRIMARILY SOUTH OF I-76. TEMPERATURES TO THE NORTH OF I-76 ARE ONLY EXPECTED TO MAKE IT TO ABOUT 30 DEGREES. TEMPERATURES TONIGHT WILL DROP BACK TO THE SINGLE DIGITS AS A WEAK SURGE OF COOLER AIR MOVES IN FROM THE NORTH. LONG TERM...NW FLOW ALOFT WILL BE OVER THE AREA ON WED AND THEN BECOME MORE WLY BY THU. CROSS-SECTIONS SHOW ANY MOISTURE WILL BE ABV 500 MB SO WILL KEEP A DRY FCST IN PLACE BOTH DAYS ALTHOUGH THERE MAYBE SOME WAVE CLOUDS FROM TIME TO TIME. TEMPS WILL CONTINUE TO MODERATE SLOWLY WITH READINGS OVER NERN CO RANGING FROM THE MID 20S TO LOWER 30S ACROSS THE PLAINS WHILE AREAS AROUND DENVER RISE INTO THE MID TO UPPER 30S. BY THU READINGS SHOULD RISE BACK INTO THE LOWER TO MID 40S OVER MOST OF NERN CO. WINDS WILL CONTINUE GUSTY IN THE MTNS AND FOOTHILLS BOTH DAYS BUT SPEEDS SHOULD STAY BLO HIGH WIND CRITERIA. BY FRI A WK UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA IN NW FLOW ALOFT. CROSS-SECTIONS SHOW ENOUGH MOISTURE FOR A CHC OF SNOW SHOWERS IN THE MTNS. OVER NERN CO A COOL FNT WILL AFFECT THE NERN PLAINS BY AFTN AND THEN BACKDOOR INTO THE FRONT RANGE BY EARLY FRI EVENING. THERE COULD BE A SLIGHT CHC OF SNOW SHOWERS OVER NERN CORNER FRI EVENING AS THE WK UPPER LEVEL TROUGH MOVES ACROSS. AS FOR HIGHS WILL KEEP READINGS IN THE LOWER TO MID 40S OVER NERN CO HOWEVER IF FNT COMES IN FASTER THEN HIGHS COULD END UP BEING COOLER. FOR SAT AND SUN BRISK NW FLOW ALOFT WILL BE OVER THE AREA WITH SOME MOISTURE AFFECTING THE MTNS. APPEARS A WK DISTURBANCE COULD LEAD TO A BETTER CHC OF SNOW SHOWERS ON SUN. OVER NERN CO OUTSIDE OF SOME MID AND HIGH CLOUDS IT LOOKS DRY BOTH DAYS. HIGHS ON SAT MAY DROP BACK INTO THE UPPER 30S TO LOWER 40S OVER NERN CO BUT THEN REBOUND BACK INTO THE 40S ON SUN. BY MON LITTLE CHANGE WILL OCCUR AS NW FLOW ALOFT REMAINS OVER THE AREA. MOISTURE DECREASES ON MON IN THE MTNS SO WILL ONLY MENTION A SLIGHT CHC OF SNOW. OVER NERN CO IT WILL BE DRY WITH HIGHS RISING INTO THE MID 40S TO NEAR 50. AVIATION...CEILINGS AND VISIBILITIES WILL REMAIN UNRESTRICTED THROUGH TODAY AND TONIGHT WITH NO PRECIPITATION EXPECTED. PERIODS OF WEST WINDS...GUSTING TO 30-35 MPH...WILL CONTINUE THIS MORNING NEAR THE FOOTHILLS AND AS FAR EAST AS KBJC...BUT ARE NOT EXPECTED TO AFFECT KDEN OR KAPA. WINDS WILL BE DIMINISHING THROUGH THE AFTERNOON HOURS. TYPICAL DRAINAGE WINDS ARE EXPECTED OVERNIGHT TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RPK AVIATION...D-L
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
100 PM EST TUE DEC 10 2013 .PREV DISCUSSION... /ISSUED 358 AM EST TUE DEC 10 2013/ SHORT TERM /TODAY THROUGH WEDNESDAY/... SHORT TERM MODELS ARE IN GOOD AGREEMENT FOR THE MOST PART ALTHOUGH SOME DISCREPANCIES NOTED...NAM/SREF FASTER AND GFS/ECMWF SLOWER TO PUSH FRONT THROUGH FORECAST AREA TODAY. RAP HAS INITIALIZED WELL AND IS HANDLING THE RAIN BAND OVER NORTHWEST GEORGIA FAIRLY WELL AND IS IN LINE WITH FASTER SOLUTIONS. TEMPERATURES REMAIN IN THE LOWER 40S ACROSS NORTHWEST GEORGIA AND WITH SLOW PROGRESS OF COLDER AIR TO THE NORTH DO NOT EXPECT WINTRY PRECIP IN THE FORECAST AREA. COLDER AIR WILL FILTER INTO PORTIONS OF NORTH GEORGIA BY MID-LATE MORNING...AND MODELS ARE TRYING TO SCATTER/CLEAR SKIES RAPIDLY BEHIND THE FRONT. THIS WILL RESULT IN MAXIMUM TEMPERATURES ACROSS NORTH GEORGIA...INCLUDING THE ATLANTA METRO AREA...THIS MORNING. COLD AIR ADVECTION BEHIND THE FRONT IS NOT IMPRESSIVE...BUT SHOULD BE ENOUGH TO OFFSET ANY HEATING BY THE SCATTERING CLOUDS WHICH WILL RESULT IN SEVERAL HOURS OF NEAR STEADY TEMPERATURES ACROSS NORTH GEORGIA. 1000-850 WINDS WILL INCREASE BEHIND THE FRONT WITH GUSTS OF 25-30MPH EXPECTED BY LATE MORNING IN NORTH GEORGIA...SPREADING SOUTHWARD INTO CENTRAL GEORGIA BY EARLY AFTERNOON AND CONTINUING THROUGH EARLY THIS EVENING. DRIER AIR FILTERING INTO THE FORECAST AREA BY TONIGHT...BUT WIND SPEEDS WILL REMAIN IN THE 5-10MPH RANGE OVERNIGHT WHICH WILL KEEP TEMPERATURES FROM RADIATING OUT AS MUCH AS THEY COULD...HOWEVER TEMPERATURES WILL DROP TO LOWER TO MID 20S NORTH GEORGIA AND IN THE MID 30S OVER CENTRAL GEORGIA BY MORNING. TEMPERATURES WILL MODERATE ON WEDNESDAY TO NEAR NORMAL AS DRY WEATHER AND MOSTLY CLEAR SKIES SET UP ACROSS THE AREA. ATWELL LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... EXTENDED BEGINS WITH LONGWAVE TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...WITH ANOTHER SHORTWAVE DIVING THROUGH THE CENTRAL PLAINS. THIS DRY WAVE WILL PUSH INTO THE SOUTHEAST THURSDAY MORNING BUT WILL BRING A REINFORCING SHOT OF COOL AIR TO THE REGION. WEAK RIDGING BUILDS IN ALOFT FRIDAY AHEAD OF A STRONG SYSTEM OVER THE DESERT SOUTHWEST. SURFACE LOW WILL PUSH INTO THE SOUTHERN PLAINS FRIDAY NIGHT...WITH STRONG SOUTHERLIES PUMPING GULF MOISTURE BACK INTO THE SOUTHEAST. PRECIP OVERSPREADS THE AREA FRIDAY NIGHT AND ESPECIALLY SATURDAY...AND GIVEN AGREEMENT BETWEEN GFS AND ECMWF AS WELL AS RUN-TO-RUN CONSISTENCY...HAVE INCREASED POPS TO CATEGORICAL ON SATURDAY. LOOKS LIKE EASILY ANOTHER INCH OF RAIN ACROSS THE AREA. THERE MAY BE ENOUGH INSTABILITY CREEPING INTO SOUTHERN ZONES SATURDAY AFTERNOON TO WARRANT ADDING THUNDER TO THE FORECAST...BUT HAVE LEFT IT OUT FOR NOW. COMPLICATING FACTOR IS DIABATICALLY ENHANCED CLASSICAL CAD DEVELOPING FRIDAY NIGHT AND EARLY SATURDAY...THOUGH RIGHT NOW THICKNESSES ACROSS GEORGIA FOR THE MOST PART LOOK TOO WARM FOR ANY WINTRY PRECIP...BUT LATER FORECASTS WILL HAVE TO BE REEVALUATED. DID ADD A BRIEF RAIN/SNOW MIX EXTREME NORTH SUNDAY MORNING AS THE COLD FRONT PUSHES THROUGH. GFS IS JUST A TAD FASTER THAN THE ECMWF BY THIS POINT SO UNCERTAINTY IS INCREASING. COOL AND WINDY BEHIND THE FRONT BUT CLEARING INTO EARLY NEXT WEEK. TDP && AVIATION... 18Z UPDATE... MVFR TO VFR CONDITIONS CURRENTLY WITH VFR CONDITIONS AREAWIDE BY 19-21Z...CONTINUING THROUGH THE REMAINDER OF THE FORECAST PERIOD. WINDS WILL REMAIN NWLY 10-16KT W/ G18-28KT THROUGH 22-24Z...BECOMING NW-N 3-6KT BY 04Z AND EVENTUALLY NE 3-5KT BY 12-14Z. //ATL CONFIDENCE...18Z UPDATE... HIGH. 20 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 53 28 55 29 / 80 0 5 5 ATLANTA 50 30 55 31 / 80 0 5 5 BLAIRSVILLE 47 22 52 23 / 60 0 5 5 CARTERSVILLE 48 24 53 26 / 70 0 5 5 COLUMBUS 59 32 59 36 / 50 0 5 5 GAINESVILLE 50 29 53 31 / 80 0 5 5 MACON 61 28 58 30 / 60 0 5 5 ROME 47 22 52 25 / 50 0 5 5 PEACHTREE CITY 49 25 55 28 / 80 0 5 5 VIDALIA 69 39 59 40 / 50 5 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ATWELL LONG TERM....TDP AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
146 PM CST TUE DEC 10 2013 .DISCUSSION... 947 AM CST FOR MORNING UPDATE... ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH. MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN. A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL... WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA. OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING FORECAST. RATZER //PREV DISCUSSION... 329 AM CST CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS. FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND. TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS. NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE 270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE. FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT. RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET. STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF 10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE. SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION. MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WEST WINDS GUSTING TO ABOUT 30KT UNTIL DARK. * SNOW START TIME OVERNIGHT AND END TIME WEDNESDAY MORNING. * TIMING OF PEAK SNOWFALL INTENSITY...WITH VSBY OCCASIONALLY DOWN TO 1/2SM AND CIGS 1000-1500 FT TO POSSIBLY IFR. RC //DISCUSSION...UPDATED 18Z... THE PRIMARY AVIATION CONCERN IS WITH A CLIPPER TYPE SYSTEM THAT WILL BRING A PERIOD OF ACCUMULATING SNOWFALL TO THE TERMINALS OVERNIGHT INTO EARLY WEDNESDAY MORNING. THROUGH THE REMAINDER OF THE DAY...EXPECT PRIMARILY VFR...THOUGH THERE COULD BE OCCASIONAL FLURRIES AND BRIEF HIGH MVFR CIGS. WESTERLY WINDS WILL GUST UP TO 30 KT OR SO UNTIL DIMINISHING WITH NIGHTFALL. WINDS WILL FURTHER DIMINISH WITH APPROACH OF LOW PRESSURE SYSTEM OVERNIGHT. DECENT AGREEMENT IN THE GUIDANCE WITH START TIME AROUND MIDNIGHT NEAR RFD AND 1 TO 2 HOURS LATER FOR THE EASTERN TERMINALS...WITH VSBY QUICKLY DROPPING TO ABOUT 1 MILE AND LOW MVFR CIGS. EXPECTING ABOUT A 3 HOUR PERIOD WITH OCCASIONAL MODERATE SNOWFALL RATES UP TO 1/2 INCH PER HOUR. FOR THE CHICAGO TERMINALS...CURRENT INDICATIONS FAVOR PEAK INTENSITY BETWEEN 9 AND 12 UTC...THOUGH TIMING MAY NEED SOME MINOR ADJUSTMENTS. DURING THIS TIME...VSBY COULD DROP TO 1/2SM WITH CIGS POSSIBLY FALLING TO IFR. THE SNOW WILL TAPER OFF BY ABOUT SUNRISE NEAR RFD AND MID MORNING TO THE EAST. AFTER THE SNOW ENDS...MID TO HIGH MVFR CIGS SHOULD SCATTER OUT BY DARK. WINDS WILL SHIFT TO NORTHWEST AND COULD GUST UP TO 20 TO 25 KT. TOTAL SNOWFALL ACCUMULATIONS WITH THE SYSTEM ARE EXPECTED TO RANGE BETWEEN 2 AND 3 INCHES. DUE TO VERY COLD TEMPERATURES...THE SNOW WILL BE VERY LIGHT AND FLUFFY AND CONDUCIVE TO SLICK RUNWAY CONDITIONS. RC //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH FOR WIND FORECAST. * MEDIUM FOR SNOW START TIME OF 08Z AND ENDING BY 15Z. * MEDIUM FOR PEAK INTENSITY BETWEEN 9Z-12Z. * HIGH FOR IFR VSBY WITH SNOW...MEDIUM FOR OCCASIONAL 1/2SM VSBY. * MEDIUM FOR 1000 TO 1500 FT CIGS WITH SNOW...LOW FOR IFR CIGS. RC //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL. SATURDAY...SNOW LIKELY. IFR. SUNDAY...CHC SNOW. IMPROVING TO VFR. MONDAY...VFR. BMD && .MARINE... 145 PM CST MARINE FORECAST CONCERNS IN ACTIVE PATTERN INCLUDE ONGOING WESTERLY GALES INTO TONIGHT...THEN AN EXTENDED PERIOD OF WEST-NORTHWEST WINDS 25-30 KT INTO THURSDAY AS ANOTHER ARCTIC HIGH BUILDS THROUGH THE OHIO VALLEY IN THE WAKE OF ANOTHER CLIPPER. WINDS SHIFT NORTH LATE THURSDAY NIGHT AS A COLD FRONT SETTLES SOUTH AFTER ANOTHER LOW PASSES NORTH OF THE LAKES. LOW PRESSURE WAS LIFTING NORTHEAST ACROSS EASTERN LAKE SUPERIOR THIS AFTERNOON...WITH A COLD FRONT TRAILING ACROSS WISCONSIN AND FAR NORTHWEST ILLINOIS. TIGHTENING OF THE GRADIENT IN ASSOCIATION WITH THE LOW...AND WITH THE PRESSURE RISE/FALL COUPLET WITH THE LOW AND APPROACHING FRONT HAS RESULTED IN WEST-SOUTHWEST GALES ACROSS THE SOUTHERN 1/2 OR SO OF LAKE MICHIGAN. WINDS WILL INCREASE THROUGH LATE AFTERNOON ACROSS NORTHERN LAKE MICHIGAN AS WELL...AS THE LOW PULLS AWAY TO THE NORTHEAST. FORECAST SOUNDINGS INDICATE THAT GALES WILL BE A LITTLE MORE MARGINAL ACROSS NORTHERN LAKE MICHIGAN THAN THEY WERE EARLIER ACROSS THE SOUTH PART OF THE LAKE...WHERE 40+ KT WINDS OCCURRED DURING THE MID/LATE MORNING HOURS. WEAK HIGH PRESSURE RIDGING WILL DEVELOP ACROSS THE LAKE TONIGHT...ALLOWING WINDS TO DECREASE SOMEWHAT...THOUGH THE MAIN HIGH WILL REMAIN WELL TO THE SOUTH ACROSS THE OHIO VALLEY. THUS A WEST-NORTHWEST GRADIENT WILL REMAIN ACROSS THE LAKE WHICH WILL CONTINUE TO SUPPORT WESTERLY 25-30 KT WINDS. A WEAK LOW WILL MOVE QUICKLY ACROSS THE MIDWEST SOUTH OF THE LAKES WEDNESDAY...WHICH WILL ALLOW A BRIEF DECREASE IN WINDS ACROSS FAR SOUTHERN LAKE MICHGAN DURING THE MORNING...THOUGH COLD ARCTIC HIGH PRESSURE WILL BUILD QUICKLY FROM THE PLAINS INTO THE OHIO VALLEY WEDNESDAY AFTERNOON AND NIGHT WHICH WILL TIGHTEN UP THE GRADIENT AGAIN ACROSS THE LAKES. THIS HIGH WILL SLOWLY DRIFT THROUGH AND SOUTH OF THE OHIO VALLEY THROUGH FRIDAY...WHILE ANOTHER LOW PASSES NORTH OF THE LAKES. THIS LOW WILL TRAIL A COLD FRONT DOWN THE LAKE THURSDAY NIGHT...SHIFTING WINDS TO THE NORTH-NORTHEAST FRIDAY. EAST-NORTHEAST WINDS WILL THEN CONTINUE INTO THE WEEKEND AS YET ANOTHER LOW/INVERTED TROUGH DEVELOPS ACROSS THE LOWER MISSISSIPPI AND OHIO VALLEYS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013- ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1134 AM CST TUE DEC 10 2013 .DISCUSSION... 947 AM CST FOR MORNING UPDATE... ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH. MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN. A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL... WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA. OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING FORECAST. RATZER //PREV DISCUSSION... 329 AM CST CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS. FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND. TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS. NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE 270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE. FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT. RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET. STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF 10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE. SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION. MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WEST WINDS GUSTING TO ABOUT 30KT UNTIL DARK. * SNOW START TIME OVERNIGHT AND END TIME WEDNESDAY MORNING. * TIMING OF PEAK SNOWFALL INTENSITY...WITH VSBY OCCASIONALLY DOWN TO 1/2SM AND CIGS 1000-1500 FT TO POSSIBLY IFR. RC //DISCUSSION...UPDATED 18Z... THE PRIMARY AVIATION CONCERN IS WITH A CLIPPER TYPE SYSTEM THAT WILL BRING A PERIOD OF ACCUMULATING SNOWFALL TO THE TERMINALS OVERNIGHT INTO EARLY WEDNESDAY MORNING. THROUGH THE REMAINDER OF THE DAY...EXPECT PRIMARILY VFR...THOUGH THERE COULD BE OCCASIONAL FLURRIES AND BRIEF HIGH MVFR CIGS. WESTERLY WINDS WILL GUST UP TO 30 KT OR SO UNTIL DIMINISHING WITH NIGHTFALL. WINDS WILL FURTHER DIMINISH WITH APPROACH OF LOW PRESSURE SYSTEM OVERNIGHT. DECENT AGREEMENT IN THE GUIDANCE WITH START TIME AROUND MIDNIGHT NEAR RFD AND 1 TO 2 HOURS LATER FOR THE EASTERN TERMINALS...WITH VSBY QUICKLY DROPPING TO ABOUT 1 MILE AND LOW MVFR CIGS. EXPECTING ABOUT A 3 HOUR PERIOD WITH OCCASIONAL MODERATE SNOWFALL RATES UP TO 1/2 INCH PER HOUR. FOR THE CHICAGO TERMINALS...CURRENT INDICATIONS FAVOR PEAK INTENSITY BETWEEN 9 AND 12 UTC...THOUGH TIMING MAY NEED SOME MINOR ADJUSTMENTS. DURING THIS TIME...VSBY COULD DROP TO 1/2SM WITH CIGS POSSIBLY FALLING TO IFR. THE SNOW WILL TAPER OFF BY ABOUT SUNRISE NEAR RFD AND MID MORNING TO THE EAST. AFTER THE SNOW ENDS...MID TO HIGH MVFR CIGS SHOULD SCATTER OUT BY DARK. WINDS WILL SHIFT TO NORTHWEST AND COULD GUST UP TO 20 TO 25 KT. TOTAL SNOWFALL ACCUMULATIONS WITH THE SYSTEM ARE EXPECTED TO RANGE BETWEEN 2 AND 3 INCHES. DUE TO VERY COLD TEMPERATURES...THE SNOW WILL BE VERY LIGHT AND FLUFFY AND CONDUCIVE TO SLICK RUNWAY CONDITIONS. RC //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH FOR WIND FORECAST. * MEDIUM FOR SNOW START TIME OF 08Z AND ENDING BY 15Z. * MEDIUM FOR PEAK INTENSITY BETWEEN 9Z-12Z. * HIGH FOR IFR VSBY WITH SNOW...MEDIUM FOR OCCASIONAL 1/2SM VSBY. * MEDIUM FOR 1000 TO 1500 FT CIGS WITH SNOW...LOW FOR IFR CIGS. RC //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL. SATURDAY...SNOW LIKELY. IFR. SUNDAY...CHC SNOW. IMPROVING TO VFR. MONDAY...VFR. BMD && .MARINE... 324 AM CST TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013- ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO 10 AM WEDNESDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM TUESDAY TO 3 AM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
208 PM CST TUE DEC 10 2013 .SHORT TERM /TODAY/... ISSUED AT 353 AM CST TUE DEC 10 2013 MAIN FORECAST CONCERN TODAY IS WITH STRONG WINDS AND LIGHT SNOW POTENTIAL EARLY THIS MORNING AND ADDITIONAL SNOW CHANCES LATE THIS AFTERNOON. LEANED TOWARD A BLEND OF THE HOPWRF/NAM12/RAP THROUGH MIDDAY TODAY...AND THEN NAM12/RAP THIS AFTERNOON. QUICK MOVING SHORTWAVE AND STRONG PV ANOMALY WILL CONTINUE TO INCREASE WINDS THIS MORNING AND PROVIDE A BLOWING SNOW POTENTIAL TO NORTHERN IOWA. LIGHT SNOW IS POSSIBLE THROUGH 12Z/13Z TIME AS SOUNDINGS LOSE ICE INTRODUCTION AND DEEP MOISTURE OVER THE FAR NORTH LATER THIS MORNING. WINDS ATOP THE MIXED LAYER NEAR 40 KNOTS AT MCW AND LIKELY WILL SEE BLSN DUE TO THE FRESH SNOW PACK THROUGH MIDDAY. WINDS DIMINISH SLIGHTLY THIS AFTERNOON AS PRESSURE GRADIENT DECREASES. SHORTWAVE QUICKLY DEPARTS THE STATE BY 15Z AND SHOULD SEE SOME CLEARING LATE THIS MORNING INTO THE EARLY AFTERNOON WITH DRY AIR ADVECTING INTO THE STATE. NEXT SHORTWAVE LOOKS TO FOLLOW A SIMILAR TRACK AND AFFECT NORTHERN IOWA...BUT DIFFERENCE WITH THIS SYSTEM IT HAS MORE MOISTURE AND FORCING. POPS INCREASE RAPIDLY PAST 21Z TODAY ACROSS THE NORTH AS NAM AND RAP CONSISTENT ON BRINGING THIS SHORTWAVE INTO THE REGION A BIT QUICKER. TEMPERATURE TREND TODAY WILL BE TRICKY AS WAA CONTINUES AHEAD OF THE TROUGH AND KEEPS THEM STEADY OR SLOWLY RISING BEFORE CAA TAKES OVER BRIEFLY LATE THIS MORNING. THEN MIXING AND SUNSHINE DOMINATE THIS AFTERNOON WARMING TEMPS AGAIN. .LONG TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 353 AM CST TUE DEC 10 2013 THE PRIMARY FORECAST CONCERN WILL BE EARLY IN THE PERIOD. NEXT SYSTEM WILL ALREADY BE ENTERING NORTHWEST IOWA BY 00Z THIS EVENING WITH A BAND OF SNOW DEVELOPING. THIS BAND OF SNOW WILL BE FOCUSED OVER THE NORTHERN HALF OF THE FORECAST AREA THOUGH SOME LIGHT SNOW MAY FAR ACROSS THE SOUTH AS WELL. THOUGH NOT AS IMPRESSIVE AS SUNDAY...A RELATIVELY GOOD LOW LEVEL DENDRITIC LAYER DEPTH OF AROUND 8 KFT. WHILE FORCING WILL BE SPREAD THROUGHOUT A DEEP LAYER AND WILL RESULT IN AN ARRAY OF FLAKE TYPES...THERE WILL BE A PERIOD OF HIGH SNOW RATIO DENDRITES. WITH LIQUID EQUIVALENT VALUES OF GENERALLY ONE TENTH INCH OR LESS WILL RESULT IN SNOWFALL OF 1 TO 2 INCHES ACROSS THE NORTH WITH A MAX CEILING OF 3 INCHES. A STRONG COLD FRONT WILL SWEEP IN IMMEDIATELY BEHIND THE SNOW AND WILL BRING ANOTHER ARCTIC SURGE AND GUSTY NORTHWEST WINDS BACK TO THE STATE. THE COLD AIR AND INCREASING WINDS WILL PRESENT A COUPLE ISSUES. THE MOST OBVIOUS WILL BE EXPECTED BITTERLY COLD WIND CHILLS OF -20 TO -30 ACROSS FAR NORTHERN PORTIONS LATE TONIGHT AND THROUGH MUCH OF WEDNESDAY MORNING. THE SECOND IS THE STRENGTH OF WINDS AND THE IMPACT ON THE NEWLY FALLEN FLUFFY SNOW AND WHAT WAS ON THE GROUND FROM SUNDAY. HIGHLY EFFICIENT MOMENTUM TRANSFER OF MIXED LAYER WINDS WILL BE PRESENT DUE TO THE STRONG COLD ADVECTION. THIS COMBINED WITH A PERIOD OF GOOD PRESSURE GRADIENT WITH A STRONG PRESSURE RISE COUPLET WILL LEAD TO STRONGER WINDS THAN MODELS CURRENTLY SUGGEST. THESE CONDITIONS SHOULD LEAD TO A PERIOD OF LOW LEVEL BLOWING SNOW WHICH MAY NOT SIGNIFICANTLY REDUCE VISIBILITIES BUT WILL LEAD TO DETERIORATED ROAD CONDITIONS. THE SNOW AND BLOWING SNOW LIKELY WILL NOT MEET WINTER WEATHER ADVISORY CRITERIA ALONG. HOWEVER...THIS LEADS TO A HEADLINE DECISION QUANDARY. WITH A GOOD CERTAINTY ON THE WIND CHILL CRITERIA BEING MET...THE BEST OPTION MAY BE TO PACKAGE EVERYTHING TOGETHER INTO A WINTER WEATHER ADVISORY. WITH IT BEING SECOND PERIOD...WILL ALLOW THE DAY SHIFT ANOTHER LOOK AS THE SYSTEM NEARS. ARCTIC COLD TEMPERATURES CAN BE EXPECTED FOR WEDNESDAY FOLLOWED BY A QUICK DROP IN THE EVENING A HIGH PRESSURE SLIDES THROUGH WITH WARM ADVECTION AND RISING TEMPERATURES AFTER MIDNIGHT. WARMER BUT SEASONABLY COLD FOR THURSDAY. ANOTHER COLD FRONT PASSES THROUGH ON FRIDAY. THERE IS POTENTIAL FOR THE STATE TO BE IMPACTED BY LIGHT SNOW WITH THE BOUNDARY ARRIVING FROM THE NORTH. ALSO MOISTURE STREAMING NORTH FROM THE GULF MAY REACH SOUTHEAST IOWA. THIS PRECIPITATION COULD FOR A WINTRY MIX WITH A WARM NOSE ALOFT NUDGING IN BEFORE THE BOUNDARY PUSHES IT SOUTH AGAIN. SIGNS POINTING TO ANOTHER ARCTIC BLAST AROUND SUNDAY TO END THE PERIOD QUITE COLD. && .AVIATION...10/18Z ISSUED AT 203 PM CST TUE DEC 10 2013 MAIN CONCERN WILL BE NEXT CLIPPER MOVING SOUTHEAST TONIGHT ACROSS REGION. SOME CONCERNS WITH BLSN AND PERIOD OF WIND BEHIND THE SYSTEM AS IT TRANSITIONS TO THE EAST DURING THE OVERNIGHT AND EARLY MORNING HOURS. MAIN BAND OF BLSN SHOULD SET UP BETWEEN KFOD AND JUST SOUTH OF KALO...BUT EVEN AN INCH OR SO OF DRY POWERDY SNOW MAY CAUSE SOME MINOR BLOWING CONCERNS AT KMCW AS WELL. WITH SOME CONSISTENCY IN EURO MODEL OVER PAST TWO RUNS WILL REMOVE BLSN FROM KDSM AS MOST OF SNOW WILL FALL NORTH. WINDS TO DIMINISH AFT 16Z WED...CIGS IMPROVE VERY QUICKLY 2-3 HOURS AFT SYSTEM EXITS. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1218 PM MST TUE DEC 10 2013 .SHORT TERM...(TONIGHT AND TOMORROW) ISSUED AT 1206 PM MST TUE DEC 10 2013 LATEST WV IMAGERY AND RAP H5 UPPER LEVEL ANALYSIS INDICATES NW FLOW EXTENDING FROM THE THE NORTHERN ROCKIES IN CANADA ACROSS THE GREAT BASIN AND INTO THE WESTERN PLAINS OF KANSAS. MID-UPPER LEVEL MOISTURE PLUME ON WV ASSOCIATED WITH MID-HIGH CLOUDS ARE MOVING INTO THE NEBRASKA PANHANDLE. THIS APPEARS TO BE ALONG THE LEADING EDE OF AN EMBEDDED SHORTWAVE TROUGH MOVING OUT OF CANADA INTO THE NORTHERN PLAINS. AT THE SURFACE A WEAK LEE TROUGH HAS DEVELOPED JUST EAST OF THE FRONT RANGE IN COLORADO WITH A SURFACE TROUGH AXIS EXTENDING NORTH ACROSS THE NEBRASKA PANHANDLE. SOUTHERLY GRADIENT EXTENDS EAST ACROSS WESTERN KANSAS AND HAS SUPPORTED GOOD WAA AND MIXING ACROSS OUR CWA WHERE TEMPS HAVE FINALLY RISEN ABOVE FREEZING FOR THE FIRST TIME IN 6 DAYS. DUE TO SNOW PACK BETTER SNOW PACK IN NE PARTS OF OUR CWA MIXING HAS BEEN LIMITED AND TEMPS HAVE STRUGGLED TO APPROACH FREEZING. THROUGH THE REST OF THE AFTERNOON WE SHOULD SEE FURTHER DETERIORATION OF SNOW PACK ACROSS OUR CWA...SO THERE SHOULD BE LESS OF AN IMPACT ON THE FORECAST FOR MOST OF OUR AREA GOING FORWARD. TONIGHT...THE SHORTWAVE TROUGH OVER MONTANA WILL SWING SOUTH THEN EAST ACROSS THE NORTHERN PLAINS PUSHING A BACKDOOR COLD FRONT OVER OUR CWA. THERE WILL BE SOME WEAK FORCING ACROSS THE NORTHERN PART OF OUR CWA...HOWEVER WITH A VERY DRY AIR MASS BELOW 12-15KFT I AM NOT ANTICIPATING ANY MEASURABLE PRECIP. COULDNT RULE OUT A FEW FLURRIES IN SW NEBRASKA...HOWEVER ITS HARD TO SAY IF THIS WOULD EVEN REACH THE SURFACE. WITH A COLD AIR SLOSHING BACK OVER OUR CWA TEMPS WILL COOL OFF ONCE AGAIN...WITH OVERNIGHT LOWS IN THE SINGLE DIGITS. WINDS AROUND 10-12KTS...CLOUD COVER...AND SLIGHTLY HIGHER SURFACE TD VALUES SHOULD LIMIT RADIATIONAL COOLING...OTHERWISE WE WOULD HAVE SEEN ANOTHER NIGHT OF BELOW ZERO TEMPS. WEDNESDAY...WHILE THE AIR ALOFT WILL BE COOLER THE PATTERN ALOFT WILL BE MUCH MORE PROGRESSIVE WITH SHORTWAVE RIDGING AND SOUTHERLY FLOW REDEVELOPING BY LATE AFTERNOON. HIGH TEMPS ARE TRICKY SINCE WE COULD SEE A GRADIENT OF MID 30S IN THE WEST ASSOCIATED WITH AFTERNOON WAA AND GOOD MIXING TO MID 20S IN THE NORTHEAST WHERE COOLER AIR WILL STILL BE IN PLACE. .LONG TERM...(TOMORROW NIGHT THROUGH NEXT TUESDAY) ISSUED AT 1206 PM MST TUE DEC 10 2013 THE CENTRAL PLAINS WILL BE UNDER VARYING DEGREES OF NORTHWEST FLOW ALOFT THROUGH THE ENTIRE PERIOD. NO SIGNIFICANT DISTURBANCES ARE FORECAST AND DRY CONDITIONS ARE EXPECTED. TEMPERATURES WILL GENERALLY BE NEAR NORMAL...ALTHOUGH A COUPLE OF BRIEF COLD AIR INTRUSIONS ARE FORECAST BY THE MODELS. THE FIRST WILL OCCUR FRIDAY NIGHT AND WILL LOWER TEMPERATURES BY 5-10 DEGREES ON SATURDAY. A SECOND SHOT OF EVEN COLDER AIR WILL EFFECT MAINLY EASTERN PARTS OF THE FORECAST AREA ON SUNDAY. MODELS DISAGREE ON HOW FAR WEST TO BRING THAT SHALLOW AIR MASS THOUGH THE COLD AIR USUALLY WINS IN THESE SITUATIONS AND HAVE HEDGED TEMPERATURES ON THE COLD SIDE OF GUIDANCE ESPECIALLY IN THE EAST. BY MONDAY ALL MODELS SHOW THE COLD AIR SCOURED OUT AND TEMPERATURES REBOUNDING. ANOTHER SLIGHTLY COOLER GLANCING BLOW MAY OCCUR ON TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1030 AM MST TUE DEC 10 2013 VFR CONDITIONS ARE EXPECTED WITH ONLY 15-20KFT CLOUDS MOVING ACROSS BOTH TERMINALS FROM THE NORTH AS UPPER LEVEL SYSTEM MOVES ACROSS THE NORTHERN PLAINS. SOUTH WINDS GUSTING 20-25KT ARE EXPECTED AT KGLD THROUGH MOST OF THIS AFTERNOON. I HAVE LESS CONFIDENCE IN AFTERNOON WINDS AT KMCK WHERE MIXING IS LIMITED BY BETTER SNOW PACK. A FRONT WILL MOVE ACROSS THE REGION TONIGHT AND AHEAD OF THIS FRONT WINDS WILL SHIFT TO THE NORTHWEST AND THEN WEST...AND REMAIN AROUND 10-12KT THROUGH MOST OF THE NIGHT. HIGH PRESSURE WILL MOVE BACK OVER BOTH TERMINALS AROUND 10Z WHICH WILL ALLOW WINDS TO GO LIGHT AND VARIABLE THROUGH THE REST OF THE TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...DR SHORT TERM...DR LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
448 PM EST TUE DEC 10 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 447 PM EST TUE DEC 10 2013 MAIN FCST CONCERN IN THE SHORT TERM REVOLVES AROUND LES TRENDS AS REINFORCING ARCTIC AIR MASS PASSES ACROSS THE AREA. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN EXPANSIVE POLAR VORTEX CENTERED OVER HUDSON BAY. WITHIN THE CIRCULATION...ONE SHORTWAVE HAS MOVED E OF UPPER MI/LAKE SUPERIOR. WAVE BROUGHT A PERIOD OF -SN WITH VERY LITTLE ACCUMULATION ACROSS MAINLY SRN AND ERN UPPER MI EARLIER TODAY. THE SMALL SNOWFLAKES WERE EXCELLENT VIS RESTRICTORS. UPSTREAM...ANOTHER SHORTWAVE WAS SWINGING THRU SRN MANITOBA/ND/NRN MN. TYPICAL FOR ARCTIC AIR MASSES...IN THE WAKE OF THE FIRST SHORTWAVE...SKIES GENERALLY CLEARED OUT AWAY FROM LAKE EFFECT AREAS. PER VIS SATELLITE IMAGERY...SFC TROF/WIND SHIFT ACROSS LAKE SUPERIOR HAS LEAD TO A BAND OF HVY LES THAT HAS SETTLED S ACROSS THE KEWEENAW TODAY. BAND IS A LITTLE MORE DISORGANIZED NOW...AND EXTENDS E ACROSS ERN LAKE SUPERIOR PER SATELLITE/KMQT RADAR IMAGERY. AS NEXT SHORTWAVE MOVES ACROSS THE AREA TONIGHT...MODELS ARE NOT INDICATING MUCH IN THE WAY OF FORCING PER QVECTORS...PROBABLY DUE TO CAA AT LOW-LEVELS. NONETHELESS...CONDITIONS ARE FAVORABLE FOR MDT/HVY LES AS INVERSIONS ARE UP AROUND 8KFT. NEGATIVE FACTOR WILL BE THE COLD AIR SUPPRESSING THE DGZ...MAINLY OVER THE W WHERE SHORTER FETCH LEADS TO LESS LAKE MODERATION/WARMING OF THE LOW-LEVELS. HAVE SOME CONCERN THAT SNOWFLAKES MAY END UP QUITE SMALL...KEEPING ACCCUMULATIONS LOWER THAN FCST. ON THE OTHER HAND...THE SMALL SNOWFLAKES CREATE MORE OF A DRIVING HAZARD DUE TO THEIR EFFECTIVENESS AT REDUCING VIS. IN ANY EVENT...ADVYS REMAIN UP FOR THE WRN COUNTIES. HEAVIEST SNOW SHOULD FOCUS ACROSS NRN ONTANAGON COUNTY INTO CNTRL HOUGHTON COUNTY...WHERE LOW-LEVEL CONVERGENCE WILL BE ESPECIALLY STRONG THRU THE EVENING. OVER THE E...NOT ONLY DOES A LONGER FETCH AND HIGHER DGZ POINT TOWARD MORE SIGNIFICANT ACCUMULATIONS...BUT THERE ARE INDICATIONS FROM ALL HIGH RES MODEL GUIDANCE FOR ONE OR TWO AREAS OF STRONGLY FOCUSED CONVERGENCE OWING TO LAND BREEZES OFF ONTARIO AND NCNTRL UPPER MI. EXACTLY WHERE THE CONVERGENCE ZONES SET UP AND WHETHER THEY REMAIN STATIONARY OR MEANDER WILL CONTROL HOW MUCH SNOW FALLS. PERUSAL OF A NUMBER OF HIGH RES MODELS SHOW WATER EQUIVALENT PCPN TOTALS ANYWHERE FROM 1.5 TO 3.5 INCHES AIMING TOWARD WHITEFISH PT VCNTY BY WED EVENING. IF SNOW RATIOS END UP AROUND 20 TO 1...YOU END UP WITH A RIDICULOUS POTENTIAL SNOW ACCUMULATION. HOW THE EXPECTED BAND OR BANDS SETUP TONIGHT WILL SET THE STAGE FOR WHETHER OR NOT THE POTENTIAL SNOW ACCUMULATION IS REALIZED SOMEWHERE OVER NE UPPER MI. OTHERWISE...OVERALL MODEL TREND SUGGESTS A LITTLE MORE NORTHERLY COMPONENT TO THE WIND...SO ADVY WAS EXPANDED TO NRN SCHOOLCRAFT COUNTY AND HEAVIER SNOW AMOUNTS WERE SPREAD A LITTLE FARTHER W IN ALGER COUNTY...THOUGH HEAVIEST SNOW BANDS SHOULD STILL END UP E OF MUNISING. ONLY OTHER ITEM OF NOTE TONIGHT WAS INCLUSION OF LOW WIND CHILLS IN HEADLINE PRODUCTS OVER WRN UPPER MI...INCLUDING WIND CHILL ADVY FOR IRON COUNTY WHICH WAS NOT UNDER HEADLINE INVOLVING SNOW. ON WED...LES WILL TREND LIGHTER OVER THE W AS INVERSIONS FALL A BIT. LES SHOULD REMAIN QUITE HEAVY OVER THE E...ESPECIALLY DURING THE MORNING WHEN CONVERGENCE REMAINS STRONG. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 410 PM EST TUE DEC 10 2013 LOOK FOR A SERIES OF SYSTEMS TO SLIDE IN ON THE NW FLOW ALOFT...KEEPING SNOW IN THE FCST FOR MUCH OF THE PERIOD. IT WILL BE A PERIOD OF ALMOST CONTINUOUS SFC TROUGHS OVER CENTRAL AND EASTERN UPPER MI. THE BUFKIT TIME HEIGHT/OVERVIEW DATA FROM THE GFS AT CMX LOOKS IMPRESSIVE. ALTHOUGH SNOW AMOUNTS ARE RELATIVELY MINIMAL...THERE IS NEARLY CONSTANT SNOW FCST THROUGH 06Z MONDAY. THE PERSISTENT 500MB TROUGH OVER EASTERN CANADA AND THE EAST HALF OF THE UNITED STATES WILL STILL BE IN PLACE WEDNESDAY NIGHT. EVEN OVER THE W HALF OF THE NATION THE SIZABLE RIDGE EXTENDING UP THROUGH THE CASCADES WILL BE UNDERMINED BY CLOSED LOW SPINNING ACROSS S CA WEDNESDAY NIGHT THROUGH THURSDAY. EXPECT NW FLOW ALOFT THROUGH THE END OF THE WORK WEEK. THE MODELS SPREAD FOR TEMPERATURES FRIDAY AFTERNOON ARE ALL OVER THE PLACE...RANGING FROM AROUND 6 TO 23 NEAR THE WI BORDER. WENT WITH A MIDDLE OF THE ROAD FCST FOR NOW WITH HIGHS IN THE TEENS CWA WIDE...AND WILL FINE-TUNE IT AS THE TIME NEARS. BY 00Z SATURDAY THE MAIN LOW WILL HAVE MOVED FROM HUDSON BAY TO CENTRAL QUEBEC...SLOWLY MARKING THE END TO ITS DOMINANCE. WHILE SOME IMPROVEMENT IN THE FRIGGED TEMPERATURES OF LATE FRIDAY INTO SATURDAY...WE WILL STILL END UP WELL BELOW THE NORMAL HIGH TEMPS FOR THIS TIME OF YEAR...WHICH MAY TYPICALLY RISE INTO THE MID TO UPPER 20S. THE NEXT QUICK MOVING WAVE IN THE 500MB NW FLOW OVER N SASKATCHEWAN AND MANITOBA AT 06Z SATURDAY WILL PUSH ACROSS THE UPPER GREAT LAKES LATE SATURDAY NIGHT THROUGH SUNDAY. EXPECT BRIEF RIDGING ALOFT SUNDAY NIGHT INTO MONDAY TO BECOME SUPPRESSED AHEAD OF THE NEXT TROUGH NEARING FROM THE NORTHWEST. THE BEST CHANCE FOR SHORT LIVED CWA-WIDE HIGH PRESSURE AT THE SFC WILL BE SUNDAY NIGHT. THIS WILL BE THE ONLY PERIOD WITH SLIGHT CHANCE POPS OR LESS ACROSS THE AREA. THE TROUGH TO THE NORTHWEST WILL LIKELY SWING ACROSS THE UPPER GREAT LAKES MONDAY...AND LINGER THROUGH TUESDAY...AS LES PICKS UP AGAIN ACROSS THE KEWEENAW PENINSULA. THE GFS AND ECMWF HAD VERY SIMILAR TIMING ON THE SFC LOW...SET UP ACROSS CENTRAL LAKE SUPERIOR AND EASTERN ONTARIO AT 18Z TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1226 PM EST TUE DEC 10 2013 KIWD...EXPECT VFR CONDITIONS TO PREDOMINATE THRU THIS AFTN BEFORE A LO PRES TROF CROSSES THE AREA THIS EVNG AND BRINGS SOME -SHSN/MVFR CONDITIONS THAT WL PERSIST FOR THE REST OF THE FCST PERIOD. KCMX...EXPECT IFR TO VLIFR CONDITIONS FOR THE FIRST FEW HRS OF THE FCST PERIOD AS A HEAVIER SN BAND ALONG A LO PRES TROF CROSSES THE KEWEENAW PENINSULA. WITH A WSHFT TO THE WNW AND GUSTY WINDS THRU THE REST OF THE FCST PERIOD BEHIND THIS TROF...THE COMBINATION OF -SHSN/ BLSN SHOULD RESULT IN PREDOMINANT IFR/LIFR VSBYS. KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD. ALTHOUGH A LO PRES TROF WL CROSS THE AREA THIS EVNG...DOWNSLOPE NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS SHOULD MAINTAIN THE VFR WX AT THIS SITE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 410 PM EST TUE DEC 10 2013 FREEZING SPRAY AND GALES TO 35-40KTS WILL BE THE MAIN CONCERNS...COMING TO AN END WEDNESDAY NIGHT. HIGH PRESSURE OVER W CANADA WILL DRIFT SE THROUGH THURSDAY NIGHT. EXPECT A TROUGH TO LINGER OVER THE UPPER GREAT LAKES DURING THE SAME TIME PERIOD. ANOTHER HIGH CENTERED OVER CENTRAL CANADA WILL THEN SLIDE ACROSS ONTARIO ON FRIDAY...AND INTO QUEBEC ON SATURDAY. ALSO FRIDAY INTO SATURDAY...A LOW WILL ORGANIZE ACROSS THE MID MISSISSIPPI VALLEY. THE LOW WILL SHIFT INTO THE NE STATES SUNDAY...WITH A TROUGH LINGERING OVER THE UPPER GREAT LAKES...AS HIGH PRESSURE SLIDES ACROSS MANITOBA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST WEDNESDAY FOR MIZ004- 084. LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR MIZ085. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ006. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ002-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001. LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009. LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST WEDNESDAY FOR MIZ010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST WEDNESDAY FOR LSZ266. GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ249-250-266. HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST THURSDAY FOR LSZ242>245-248>251-263>265. HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY FOR LSZ162-240-241. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST WEDNESDAY FOR LMZ221- 248-250. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...KC MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 PM EST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 557 AM EST TUE DEC 10 2013 MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE AREAS. WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW OUT OVER LAKE SUPERIOR EARLY THIS MORNING. TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION (LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE. WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST 2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND -25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY. WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY AND A LES WARNING FOR LUCE COUNTY. WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR -10F. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 410 PM EST TUE DEC 10 2013 LOOK FOR A SERIES OF SYSTEMS TO SLIDE IN ON THE NW FLOW ALOFT...KEEPING SNOW IN THE FCST FOR MUCH OF THE PERIOD. IT WILL BE A PERIOD OF ALMOST CONTINUOUS SFC TROUGHS OVER CENTRAL AND EASTERN UPPER MI. THE BUFKIT TIME HEIGHT/OVERVIEW DATA FROM THE GFS AT CMX LOOKS IMPRESSIVE. ALTHOUGH SNOW AMOUNTS ARE RELATIVELY MINIMAL...THERE IS NEARLY CONSTANT SNOW FCST THROUGH 06Z MONDAY. THE PERSISTENT 500MB TROUGH OVER EASTERN CANADA AND THE EAST HALF OF THE UNITED STATES WILL STILL BE IN PLACE WEDNESDAY NIGHT. EVEN OVER THE W HALF OF THE NATION THE SIZABLE RIDGE EXTENDING UP THROUGH THE CASCADES WILL BE UNDERMINED BY CLOSED LOW SPINNING ACROSS S CA WEDNESDAY NIGHT THROUGH THURSDAY. EXPECT NW FLOW ALOFT THROUGH THE END OF THE WORK WEEK. THE MODELS SPREAD FOR TEMPERATURES FRIDAY AFTERNOON ARE ALL OVER THE PLACE...RANGING FROM AROUND 6 TO 23 NEAR THE WI BORDER. WENT WITH A MIDDLE OF THE ROAD FCST FOR NOW WITH HIGHS IN THE TEENS CWA WIDE...AND WILL FINE-TUNE IT AS THE TIME NEARS. BY 00Z SATURDAY THE MAIN LOW WILL HAVE MOVED FROM HUDSON BAY TO CENTRAL QUEBEC...SLOWLY MARKING THE END TO ITS DOMINANCE. WHILE SOME IMPROVEMENT IN THE FRIGGED TEMPERATURES OF LATE FRIDAY INTO SATURDAY...WE WILL STILL END UP WELL BELOW THE NORMAL HIGH TEMPS FOR THIS TIME OF YEAR...WHICH MAY TYPICALLY RISE INTO THE MID TO UPPER 20S. THE NEXT QUICK MOVING WAVE IN THE 500MB NW FLOW OVER N SASKATCHEWAN AND MANITOBA AT 06Z SATURDAY WILL PUSH ACROSS THE UPPER GREAT LAKES LATE SATURDAY NIGHT THROUGH SUNDAY. EXPECT BRIEF RIDGING ALOFT SUNDAY NIGHT INTO MONDAY TO BECOME SUPPRESSED AHEAD OF THE NEXT TROUGH NEARING FROM THE NORTHWEST. THE BEST CHANCE FOR SHORT LIVED CWA-WIDE HIGH PRESSURE AT THE SFC WILL BE SUNDAY NIGHT. THIS WILL BE THE ONLY PERIOD WITH SLIGHT CHANCE POPS OR LESS ACROSS THE AREA. THE TROUGH TO THE NORTHWEST WILL LIKELY SWING ACROSS THE UPPER GREAT LAKES MONDAY...AND LINGER THROUGH TUESDAY...AS LES PICKS UP AGAIN ACROSS THE KEWEENAW PENINSULA. THE GFS AND ECMWF HAD VERY SIMILAR TIMING ON THE SFC LOW...SET UP ACROSS CENTRAL LAKE SUPERIOR AND EASTERN ONTARIO AT 18Z TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1226 PM EST TUE DEC 10 2013 KIWD...EXPECT VFR CONDITIONS TO PREDOMINATE THRU THIS AFTN BEFORE A LO PRES TROF CROSSES THE AREA THIS EVNG AND BRINGS SOME -SHSN/MVFR CONDITIONS THAT WL PERSIST FOR THE REST OF THE FCST PERIOD. KCMX...EXPECT IFR TO VLIFR CONDITIONS FOR THE FIRST FEW HRS OF THE FCST PERIOD AS A HEAVIER SN BAND ALONG A LO PRES TROF CROSSES THE KEWEENAW PENINSULA. WITH A WSHFT TO THE WNW AND GUSTY WINDS THRU THE REST OF THE FCST PERIOD BEHIND THIS TROF...THE COMBINATION OF -SHSN/ BLSN SHOULD RESULT IN PREDOMINANT IFR/LIFR VSBYS. KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD. ALTHOUGH A LO PRES TROF WL CROSS THE AREA THIS EVNG...DOWNSLOPE NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS SHOULD MAINTAIN THE VFR WX AT THIS SITE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 410 PM EST TUE DEC 10 2013 FREEZING SPRAY AND GALES TO 35-40KTS WILL BE THE MAIN CONCERNS...COMING TO AN END WEDNESDAY NIGHT. HIGH PRESSURE OVER W CANADA WILL DRIFT SE THROUGH THURSDAY NIGHT. EXPECT A TROUGH TO LINGER OVER THE UPPER GREAT LAKES DURING THE SAME TIME PERIOD. ANOTHER HIGH CENTERED OVER CENTRAL CANADA WILL THEN SLIDE ACROSS ONTARIO ON FRIDAY...AND INTO QUEBEC ON SATURDAY. ALSO FRIDAY INTO SATURDAY...A LOW WILL ORGANIZE ACROSS THE MID MISSISSIPPI VALLEY. THE LOW WILL SHIFT INTO THE NE STATES SUNDAY...WITH A TROUGH LINGERING OVER THE UPPER GREAT LAKES...AS HIGH PRESSURE SLIDES ACROSS MANITOBA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST WEDNESDAY FOR MIZ004- 084. LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR MIZ085. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ006. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ002-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001. LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009. LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST WEDNESDAY FOR MIZ010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST WEDNESDAY FOR LSZ266. GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ249-250-266. HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST THURSDAY FOR LSZ242>245-248>251-263>265. HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY FOR LSZ162-240-241. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST WEDNESDAY FOR LMZ221- 248-250. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...KC MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1228 PM EST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 557 AM EST TUE DEC 10 2013 MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE AREAS. WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM. THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW OUT OVER LAKE SUPERIOR EARLY THIS MORNING. TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION (LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE. WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST 2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND -25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY. WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY AND A LES WARNING FOR LUCE COUNTY. WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR -10F. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 534 AM EST TUE DEC 10 2013 CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE WEEKEND. WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL TONIGHT. THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE. INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES INTENSITY GREATLY WEDNESDAY EVENING. A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA. HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING. MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES WILL NOT BE OUT OF THE QUESTION QUITE YET. THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE ENOUGH TO DISRUPT REMAINING LES. FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A DUSTING OF SNOW. MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1226 PM EST TUE DEC 10 2013 KIWD...EXPECT VFR CONDITIONS TO PREDOMINATE THRU THIS AFTN BEFORE A LO PRES TROF CROSSES THE AREA THIS EVNG AND BRINGS SOME -SHSN/MVFR CONDITIONS THAT WL PERSIST FOR THE REST OF THE FCST PERIOD. KCMX...EXPECT IFR TO VLIFR CONDITIONS FOR THE FIRST FEW HRS OF THE FCST PERIOD AS A HEAVIER SN BAND ALONG A LO PRES TROF CROSSES THE KEWEENAW PENINSULA. WITH A WSHFT TO THE WNW AND GUSTY WINDS THRU THE REST OF THE FCST PERIOD BEHIND THIS TROF...THE COMBINATION OF -SHSN/ BLSN SHOULD RESULT IN PREDOMINANT IFR/LIFR VSBYS. KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD. ALTHOUGH A LO PRES TROF WL CROSS THE AREA THIS EVNG...DOWNSLOPE NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS SHOULD MAINTAIN THE VFR WX AT THIS SITE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 557 AM EST TUE DEC 10 2013 AFTER A DECREASE IN SOUTHWEST WINDS THIS MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR AND COULD PRODUCE GALES FOR THE SOUTH CENTRAL LAKE LATE THIS AFTERNOON INTO THIS EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST WEDNESDAY FOR MIZ004- 084. LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ006. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ002-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001. LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009. LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST THURSDAY FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 PM EST WEDNESDAY FOR LSZ266. GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR LSZ266. HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 AM EST THURSDAY FOR LSZ242>245-248>251-263>265. HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY FOR LSZ162-240-241. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR LMZ221-248-250. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...KC MARINE...VOSS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
247 PM CST TUE DEC 10 2013 .SHORT TERM...TONIGHT THROUGH FRIDAY. MAIN ISSUE IN THE SHORT TERM DEALS WITH FAST MOVING CLIPPER EARLY TONIGHT. EARLY AFTERNOON SATELLITE IMAGERY SHOWED UPPER SHORTWAVE ENERGY DIGGING THRU MT INTO NRN WY. MOISTURE WITH THIS SYSTEM WILL BE QUITE LIMITED AS IT PASSES THROUGH NEBR...ALTHOUGH WITH ARCTIC NATURE TO AIRMASS ASSOCD WITH IT...ANY SNOW TO LIQUID RATIOS WILL BE HIGH AND COULD AVERAGE AROUND 20-1 OR BETTER. ALTHOUGH THERE WAS FAIRLY DECENT MODEL AGREEMENT IN PLACING THE HIGHER QPF FROM THIS SYSTEM MOSTLY N-NE OF FORECAST AREA...WITH H5/H7 HEIGHT FALLS WITH IT AT 12Z OVER WRN MT-ERN WA...SOME DIGGING IS POSSIBLE. THUS WILL LEAN TOWARD 17Z RAP IN PLACING A SECOND AREA OF LIGHT PRECIP FARTHER SW REACHING NWRN ZONES BY EARLY EVENING AND NEAR THE OMAHA METRO AN HR OR TWO EITHER SIDE OF MIDNIGHT. WITH TEMPERATURES FALLING SHARPLY BEHIND CLIPPER/ARCTIC FRONT LATE TNGT/WED AM...WILL ADJUST HOURLIES TO ACCOUNT FOR A 14Z LOW NEAR A MAV/MET BLEND FOR NOW. A FEW NRN COUNTIES TOUCH -20 WIND CHILLS FOR AN HOUR OR TWO WED MORNING BUT WITH AREAL COVERAGE AND LENGTH OF TIME OF COLDEST LIMITED...NO HEADLINES AT THIS TIME. NEXT FAST MOVING CLIPPER WAS FORECAST TO ALREADY BRING RETURN FLOW TO AREA BY WED EVENING...ALTHOUGH THIS ONE FORECAST TO BE FARTHER NE AND WEAKER...SO NO PRECIP EXPECTED FOR US. COUNTING ON ENOUGH DECOUPLING IN THE EVENING TO ALLOW READINGS TO FALL INTO LOW/MID SINGLE DIGITS...WHICH POSSIBLY MAY NOT BE MUCH LOWER THAN SOME AFTN TEMPS NERN ZONES. NON-DIURNAL ADJUSTMENTS WILL BE MADE AS WELL WITH READINGS LEVELING OFF/RISING LATER WED NIGHT. THURSDAY APPEARS AT LEAST AS MILD AS TODAY IF NOT WARMER AS H85 TEMPS ARE AT LEAST +5 DEG C WARMER THAN TDA. SNOW COVER WILL MODERATE WARMUP AND THUS MAX TEMPS WERE KEPT ON LOWER SIDE OF GUIDANCE...EXCEPTION MAY BE THINNER AREA OF SNOW COVER PARTS OF WCNTRL ZONES NEAR/NW OF COLUMBUS. WINDS SHOULD DROP OFF THU EVENING AS A WEAK FRONT SLIPS INTO NEBR ...THUS TEMPS WERE LOWERED WITH LIGHTER WINDS EXPECTED AND RESIDUAL SNOW LINGERING. LEFT FRIDAY DRY FOR NOW AS MOISTURE ARRIVING PER CROSS SECTIONS WAS SHALLOW UNTIL NEAR OR AFTER 00Z SAT. THAT SAID A FASTER SOLUTION OR A BIT DEEPER LOW LEVEL MOISTURE COULD ALLOW FOR A LIGHT PRECIP MIX TO DEVELOP SERN ZONES LATE IN THE AFTERNOON AND THIS WILL NEED MONITORING IN LATER FORECASTS. KEPT HIGHS MOSTLY AOB FREEZING. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY MODEL CONTINUITY IS NOT GREAT IN THE EXTENDED...WITH LOW CONFIDENCE ON TEMPERATURE SWINGS AND CHANCES FOR PRECIPITATION ASSOCIATED WITH FAST-MOVING AND POORLY-TIMED SHORTWAVES. AS A RESULT...KEPT FORECAST GRIDS CLOSE TO THE BLENDS FOR NOW...UNTIL BETTER AGREEMENT OR RUN-TO-RUN CONSISTENCY FAVORS ONE SOLUTION OVER ANOTHER. ECMWF/GFS INDICATE SOME POTENTIAL FOR FLURRIES OR LIGHT SNOW ON FRIDAY NIGHT AS AN UPPER-LEVEL TROUGH KICKS OUT OF THE SOUTHERN PLAINS AND ACROSS KS/MO...WITH A NORTHERN STREAM TROUGH ALSO DIVING OUT OF THE DAKOTAS TOWARD IA. BETTER CHANCES OF PRECIP EXIST TO OUR EAST AS THE TWO WAVES APPROACH EACH OTHER...LIKELY PHASING OVER THE GREAT LAKES...BUT POTENTIAL FOR LIGHT SNOW WARRANTS SLIGHT CHANCE POPS IN OUR EAST FOR NOW. IN WAKE OF THE TROUGH...COLD AIR WILL SPILL INTO THE AREA AGAIN FOR AT LEAST SUNDAY...BRINGING TEMPS WELL BELOW CLIMO AT LEAST FOR THE DAY BEFORE SOME MODERATION ARRIVES ON SUNDAY NIGHT/MONDAY. ECMWF SOLUTION ON MONDAY/TUESDAY HAS 850MB TEMPS SEVERAL DEGREES COOLER THAN GFS...AND ALSO IS A LITTLE MORE ACTIVE...WITH SHORTWAVES BRINGING AT LEAST CLOUDS IF NOT VERY LIGHT PRECIPITATION ON BOTH SUNDAY AND MONDAY...WHILE GFS REMAINS DRY. HAVE KEPT GRIDS DRY FROM SUNDAY ONWARD...AS ANY PRECIP CHANCES THAT DO APPEAR IN MODEL SOLUTIONS SEEM VERY LIGHT...WEAKLY FORCED...AND FAST MOVING. BOTH CLOUDS AND SNOW COVER COULD HOLD TEMPS BACK EVEN IF MID-LEVEL TEMPERATURES DO WARM INTO THE SINGLE DIGITS ABOVE ZERO...AND THOUGHT BLENDS CAPTURED TEMPERATURE POTENTIAL WELL ENOUGH FOR NOW. MAYES && .AVIATION... 18Z TAFS FOR KOMA...KLNK...KOFK. FAST MOVING CLIPPER SYSTEM COMING OUT OF THE NORTHERN HIGH PLAINS WILL DRAG ANOTHER COLD FRONT THROUGH EASTERN NEBRASKA BETWEEN 00Z-06Z WITH WINDS SHIFTING TO THE NORTHWEST AND INCREASING TO 10-20KTS. MAIN BAND OF SNOW EXPECTED NORTH AND EAST OF TAF SITES WITH MID LEVEL CIGS THROUGH 09Z THEN CLEARING. FOBERT && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1155 AM EST TUE DEC 10 2013 .SYNOPSIS... A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1130 AM TUESDAY...COMPLEX WEATHER SCENARIO FOR TODAY WITH LOW PRESSURE SYSTEM OVER THE CAROLINAS. WARM AND MOIST AIR IN PLACE AHEAD OF COLD FRONT BUT RADAR SHOWING DISTINCT LINE OF SHALLOW CONVECTION WITH DISTINCT WIND SHIFT BEHIND IT...BUT NO TEMP CHANGE. THIS LINE WILL ADVANCE EAST BRINGING A QUICK SHOT OF PCP UP TO A TENTH OF AN INCH AS NOTED ON OBS. THIS LINE WILL REACH THE COAST BETWEEN 1 AND 2PM BRINGING GUSTY WESTERLY WINDS BEHIND IT. FLORENCE AND LUMBERTON OBS SHOWED A GUST AROUND 30 MPH JUST AFTER 11 AM. PCP WILL KEEP TEMPS FROM RISING TOO MUCH IN MOST PLACES AND THEN COLD FRONT WILL PUSH THROUGH BY EARLY TO MID AFTN. TEMPS AT H85 WILL RISE UP TO 12C BY NOON TIME AND THEN WILL PLUMMET THROUGH THIS AFTN DOWN CLOSE TO 4C BY MIDNIGHT. COOLER WATERS KEEPING TEMPS MUCH COOLER...CLOSER TO 60...ALONG THE BEACHES AND UP THROUGH BRUNSWICK COUNTY WHERE ON SHORE FLOW IS MAXIMIZED. THIS IS ALSO LEADING TO ANOTHER ROUND OF SEA FOG AS WARMER MOISTER AIR JUST ABOVE THE SURFACE IS MOVING ATOP THE COOLER WATERS. ISSUED SPECIAL WEATHER STATEMENT TO ADDRESS LOCALIZED FOG OVER SHELF WATERS SOUTH MAINLY ADVECTING FROM SOUTH OF CAPE FEAR ON SHORE OVER BRUNSWICK COUNTY. LLJ UP TO 55 KTS PUMPING PLENTY OF WARM AND MOIST AIR AHEAD OF COLD FRONT. CONVECTIVE INDICES LOOK LIKE WE COULD SEE SOME LOW TOP CONVECTION AND POSSIBLY A RUMBLE OF THUNDER. BEST LIFT SHOULD COME JUST AHEAD OF COLD FRONT THROUGH THIS AFTERNOON LEAVING A NARROW WINDOW BUT MAY INCLUDE MENTION OF ISO THUNDER IN GRIDS. SFC BASED CAPE VALUES REACH UP TO 600 JKG. MAY SEE MORE STABLE MARINE LAYER COME INTO PLAY AS STORMS MOVE CLOSER TO THE COAST...BUT EXPECT SHOWERS AHEAD OF FRONT THROUGH EARLY AFTERNOON. WINDS WILL COME AROUND TO THE W-NW BY EARLY THIS AFTERNOON BUT COLD AIR WILL LAG BEHIND. PLENTY OF COLD AND DRY AIR WILL ADVECT IN AND SCOUR OUT ALL THE LOW CLOUDS...FOG AND ANY SHOWERS OR PCP ACROSS THE AREA. THIS WILL LEAD TO FALLING TEMPS ACROSS THE AREA THROUGH THIS EVENING. AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS A STRONG COLD ADVECTION REGIME SETS UP WITH ABOUT A 40 DEGREE DROP IN BOTH TEMPS AND DEWPOINT TEMPS BY MORNING AS COLD AND DRY AIR COMES RUSHING IN. CLEARING SKIES OVERNIGHT WILL COMBINE WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP INTO THE LOWER TO MID 30S. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY. THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN CLOUDS OUT OF THE MIX FOR THE MOST PART. A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH MOST AREAS SEEING MID TO UPPER 20S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING. HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO CHANGES TO TEMPERATURE FORECAST. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95 CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON. CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD. EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1130 AM TUESDAY...AREAS OF DENSE FOG CONTINUES ACROSS THE WATERS BUT GUSTY WESTERLY WINDS WILL WORK THEIR WAY IN BEHIND LINE OF CONVECTION HEADING OVER THE WATERS EARLY THIS AFTERNOON. SMALL CRAFT ADVISORY REMAINS IN EFFECT. FRYING PAN SHOWING SEAS CLOSE TO 9 FT...AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL TURN W-NW AND BECOME GUSTY THIS AFTERNOON CAUSING NEAR-SHORE SEAS TO SUBSIDE. ALL LOCAL WATERS WILL DROP BELOW SMALL CRAFT ADVISORY CRITERIA IN STRONG OFF SHORE FLOW BY TONIGHT. SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO 15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD. LONG TERM /FRIDAY THROUGH SATURDAY/... AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING WINDS AND SEAS FOR SATURDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ250- 252-254-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250- 252-254-256. && $$ NEAR TERM...RGZ SHORT TERM...SHK LONG TERM...SHK AVIATION...DL
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 246 PM CST TUE DEC 10 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE EARLIER CLIPPER EXITING THE REGION OVER NORTHEAST LOWER MICHIGAN. PARTIAL CLEARING HAS OCCURRED BEHIND THE SYSTEM ACROSS THE STATE...BUT LIKE YESTERDAY...STRATO-CU KEEPS RE-DEVELOPING WITHIN THE ARCTIC AIRMASS DUE TO STEEP LOW-LEVEL LAPSE RATES. LIGHT SNOW SHOWERS/FLURRIES ARE NOT AS WIDESPREAD AS YESTERDAY...BUT ARE STILL SHOWING UP ON RADAR MAINLY OVER CENTRAL AND SOUTHERN WISCONSIN. THESE LIGHT SNOW SHOWERS/FLURRIES SHOULD AGAIN SUBSIDE AROUND SUNSET. THEN ATTENTION TURNS TO THE VARIOUS SHORTWAVES/CLIPPERS UPSTREAM. ONE CLIPPER OVER LAKE WINNIPEG IS ANTICIPATED TO SWING ACROSS LAKE SUPERIOR AND THE UPPER PENINSULA TONIGHT. A MORE POTENT WAVE RESIDES OVER MONTANA WHICH WILL ALSO MOVE ACROSS THE REGION LATE OVERNIGHT. AS A RESULT...LIGHT SNOW POTENTIAL AND WIND CHILL HEADLINES ARE THE MAIN FORECAST CONCERNS IN THE SHORT TERM. TONIGHT...ANOTHER FAST MOVING CLIPPER SYSTEM WILL SLIDE QUICKLY SOUTHEAST INTO THE WESTERN GREAT LAKES/NORTHERN MISSISSIPPI VALLEY. AHEAD OF THE SHORTWAVE...A WEAK SURFACE CIRCULATION WILL MOVE ACROSS IOWA AND INTO NORTHERN ILLINOIS. FORCING IS NOT NEARLY AS ROBUST AS THE PAST CLIPPER...AND THE TRACK IS A COUPLE HUNDRED MILES FURTHER SOUTH AS WELL. BUT SEEMS TO HAVE ENOUGH MOISTURE ON THE NORTHERN PERIPHERY OF THE SYSTEM FOR LIGHT SNOW TO GRAZE CENTRAL AND EAST-CENTRAL WISCONSIN COUNTIES. HAVE KEPT THE CHANCE OF SNOW IN THE FORECAST...BUT DID DELAY THE ARRIVAL A COUPLE HOURS TO MATCH THE LATEST TRENDS. AS THE CLIPPER PASSES BY TO THE SOUTH...SHOULD SEE A SECONDARY SURGE OF ARCTIC AIR ARRIVE LATE TONIGHT. THEREFORE ANTICIPATE WIND CHILL READINGS TO FALL OFF QUICKLY OVERNIGHT AS THIS SURGE OF ARCTIC AIR SPREADS EAST. ALREADY WILL BE NEAR WIND CHILL ADVISORY CRITERIA OVER N-C WISCONSIN FOR THE EVENING...SO WILL NOT TAKE MUCH COLDER AIR FOR CRITERIA TO BE MET. WILL KEEP THE START TIME AS PLANNED...THOUGH N-C WISCONSIN MAY SEE THE CRITERIA BREACHED AN HOUR OR TWO BEFORE ISSUANCE TIME. LITTLE CHANGE TO LOW TEMPS. WEDNESDAY...CLEARING SKIES WILL TAKE PLACE WEDNESDAY MORNING AS THE CORE OF THE ARCTIC AIR MOVES INTO THE FORECAST AREA. DESPITE MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS...TEMPS WILL STRUGGLE TO RISE ABOVE 0 DEGREES OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. WIND CHILL READINGS MAY RISE ABOVE ADVISORY CRITERIA FOR A FEW HOURS DURING THE AFTERNOON OVER NORTHEAST WISCONSIN...ONLY TO FALL BELOW AGAIN BY THE START OF THE EVENING. WILL THEREFORE LET THE WIND CHILL HEADLINES GO INTO THE NEXT PERIOD. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 246 PM CST TUE DEC 10 2013 CONTINUED COLD TEMPERATURES AND PERIODIC SNOW CHANCES...MOST NOTABLY FRIDAY NIGHT INTO SATURDAY...WILL BE THE MAIN FCST CONCERNS. MOSTLY CLEAR SKIES WILL ALLOW TEMPS TO FALL WELL BLO ZERO WEDNESDAY EVENING...BUT WAA AND INCREASING CLOUDS WILL PROBABLY RESULT IN STEADY OR SLOWLY WARMING TEMPS BEFORE DAYBREAK. ENOUGH SATURATION SHOULD OCCUR OVER OUR SW COUNTIES LATE TO ALLOW SOME LIGHT SNOW OR FLURRIES TO DEVELOP. STEADY WEST WINDS AND VERY COLD TEMPS WILL RESULT IN BITTER COLD WIND CHILLS...WHICH WILL LINGER INTO EARLY THURSDAY. HAVE EXTENDED THE WIND CHILL ADVISORY UNTIL 15Z THU. WILL EVENTUALLY NEED TO ADD THE LAKESHORE COUNTIES TO THE ADVISORY FOR WEDS NGT...BUT THAT CAN BE DONE WITH SUBSEQUENT FCSTS. A VERY STRONG BAROCLINIC ZONE WILL BE IN PLACE FROM THURSDAY INTO FRIDAY. WITH WAA CONTINUING ON THURSDAY...AND THE RRQ OF AN UPPER JET...FRONTOGENETIC FORCING AND WEAK SHORT-WAVE ENERGY AFFECTING THE REGION THU NGT/FRI...ENOUGH FORCING SHOULD BE PRESENT TO CONTINUE A CHANCE OF LIGHT SNOW/FLURRIES THROUGH THE PERIOD. A MODEST MODERATION IN TEMPS WILL OCCUR LATE IN THE WORK WEEK... BUT BACKED OFF A LITTLE ON THE PREVIOUS MAX TEMPS FOR FRIDAY. ITS STARTING TO LOOK MORE INTERESTING LATE FRI NGT/SATURDAY AS AN INVERTED SFC TROF MOVES THROUGH THE REGION. LOW-LEVEL CONVERGENCE IS EXPECTED TO BE QUITE STG IN THE FOX VALLEY/LKSHR AREAS...AND SYNOPTIC FORCING SHOULD BE PROVIDED BY H8 WAA/ISENT LIFT AND SOME UPPER JET ENERGY. LAKE-ENHANCEMENT IS LIKELY...WITH E-SE WINDS OFF LAKE MICHIGAN AND LK-H8 DELTA-T`S OF 14-18 C. WILL RAISE POPS TO LIKELY OVER THE FOX VALLEY AND ESPECIALLY THE LAKESHORE COUNTIES...AND MENTION THE POSSIBILITY OF 2-4 INCH ACCUMS (WITH LOCAL HIGHER AMOUNTS ON THE LKSHR) IN THE HAZARDOUS WEATHER OUTLOOK. THE FCST IS UP IN THE AIR SATURDAY NIGHT/SUNDAY...AS SOME OF THE MEDIUM RANGE MODELS (ESPECIALLY THE GFS) BRING AN UPPER LOW FARTHER SOUTH (THROUGH WI) AND LINGER THE INVERTED SFC TROF OVER THE WESTERN GREAT LAKES REGION. ALTHOUGH THE ECMWF WAS STILL TAKING THE UPPER LOW THROUGH LAKE SUPERIOR...IT HAD SHOWN A FARTHER SOUTH SOLN A COUPLE DAYS AGO...SO THIS BEARS WATCHING. AT THE LEAST...IT APPEARS THAT COLD CYCLONIC NORTH FLOW WILL BRING ANOTHER SHOT OF ARCTIC AIR INTO THE REGION BY SUDAY...AND CAUSE LAKE-ENHANCED SNOW TO INCREASE OVER NC WI. AT WORST... ACCUMULATING SNOW COULD CONTINUE ACROSS MUCH OF THE FORECAST AREA SATURDAY NIGHT INTO SUNDAY MORNING. FOR NOW...HAVE JUST INCREASED POPS OVER THE LAKE SUPERIOR SNOW BELT. THE ARCTIC SURGE SHOULD BE BRIEF. THE CHANCE OF LIGHT SNOW OR FLURRIES WILL CONTINUE EARLY NEXT WEEK...AS SEVERAL S/W TROFS MOVE THROUGH THE WESTERN GREAT LAKES...AND THE ARCTIC BAROCLINIC ZONE OSCILLATES OVER THE REGION. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1123 AM CST TUE DEC 10 2013 FAST MOVING CLIPPER IS EXITING THE REGION LATE THIS MORNING. SKIES HAVE PARTIALLY CLEARED BEHIND THE SYSTEM THOUGH SCT TO BKN MVFR CIGS ARE TRYING TO RE-DEVELOP ACROSS THE STATE WITH DAYTIME HEATING. A FEW SPOTTY FLURRIES OR LIGHT SNOW SHOWERS ARE NOT OUT OF THE QUESTION EITHER. WEST WINDS WILL BECOME GUSTY ONCE AGAIN THIS AFTERNOON...WHICH WILL CREATE BLOWING SNOW ESPECIALLY IN THE OPEN FIELDS. WINDS PARTIALLY CALM TONIGHT AS ANOTHER FAST MOVING CLIPPER PASSES SOUTH OF THE REGION. MID LEVEL CLOUDS WILL BE INCREASING THIS EVENING...AND A SMALL CHANCE OF LIGHT SNOW WILL MOVE INTO CENTRAL AND EAST-CENTRAL WISCONSIN AFTER MIDNIGHT. THE CLIPPER WILL QUICKLY EXIT THE REGION EARLY WEDNESDAY MORNING...LEAVING MOSTLY CLEAR AND VERY COLD CONDITIONS IN PLACE FOR MUCH OF THE DAY. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 3 AM WEDNESDAY TO 9 AM CST THURSDAY FOR WIZ013-020-021-031-037>039-045-048-049-073-074. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY FOR WIZ005-010>012-018-019-030-035-036. && $$ SHORT TERM.....MPC LONG TERM......KIECKBUSCH AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 AM CST TUE DEC 10 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CST TUE DEC 10 2013 CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING OVER THE EAST PACIFIC...TROUGHING OVER CENTRAL AND EASTERN CANADA AND SOUTHWARD INTO THE UPPER MIDWEST. WITHIN THIS TROUGH...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST MINNESOTA WHILE ANOTHER SHORTWAVE COULD BE SEEN UPSTREAM IN CENTRAL ALBERTA. THE STRONG DPVA FORCING AHEAD OF THE POTENT SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND SOME MOISTURE HAS HELPED SPREAD CLOUDS ACROSS THE FORECAST AREA. IN ADDITION...LIGHT SNOW WAS MOVING ACROSS THE FORECAST AREA. ALSO ACCOMPANYING THE POTENT SHORTWAVE WAS A RELATIVELY DEEP SURFACE LOW CENTERED NEAR MINNEAPOLIS. THE COMBINATION OF THE CLOUDS AND STRENGTHENING SOUTHERLY WINDS AHEAD OF THE LOW HAVE HELPED TO BRING TEMPERATURES UP THROUGH THE NIGHT. MOST WIND CHILLS ARE ABOVE ADVISORY CRITERIA OF -20F...THUS WE WERE ABLE TO CANCEL TAYLOR/CLARK EARLY. SIMILARLY...ON THE BACK SIDE OF THE SURFACE LOW WHERE PRESSURES ARE RISING RAPIDLY...STRONG NORTHWEST WINDS ARE OCCURRING. THESE ARE ADVECTING IN A BRIEF SURGE OF ARCTIC AIR CHARACTERIZED BY 850MB TEMPS OF -20C PER RAP ANALYSIS. SKIES BEGIN TO CLEAR OUT QUICKLY TOO ON THE BACK SIDE OF THE LOW. THE POTENT SHORTWAVE IN MINNESOTA REMAINS PROGGED TO FLY THROUGH THE FORECAST AREA THIS MORNING...SUCH THAT IT IS ALREADY IN LOWER MICHIGAN BY 18Z. WHAT THIS MEANS IS WE SHOULD HAVE A BRIEF PERIOD OF SNOW FOR THE EARLY MORNING HOURS...AFFECTING THE MORNING COMMUTE. ONCE THE WAVE PASSES...EXPECTING WINDS TO CRANK UP OUT OF THE WEST AS PRESSURES RISE RAPIDLY. GUSTS ARE LIKELY TO RANGE 25-35 KT WITH THE PRESSURE RISE COMING IN...HIGHEST IN SOUTHEAST MN. SOME BLOWING AND DRIFTING OF ALL THE RECENT SNOW IS LIKELY. IT APPEARS BRISK WINDS WILL PERSIST UNTIL LATE IN THE DAY WHEN A SURFACE RIDGE BUILDS IN. THE BRISK WINDS WILL ALSO BRING IN COLDER AIR...CAUSING TEMPS TO FALL...DESPITE INCREASING SUNSHINE. THE CLEARING THIS AFTERNOON LOOKS TO BE SHORT-LIVED...HOWEVER. THE NEXT SHORTWAVE OVER ALBERTA IS PROGGED TO DROP DOWN INTO WESTERN IOWA BY 12Z WEDNESDAY. AS THIS OCCURS...A MID-LEVEL FRONTOGENESIS BAND WILL SET UP AHEAD OF IT. 10.00Z GFS/NAM/ECMWF/CANADIAN TRACK THIS BAND FROM SOUTH DAKOTA THIS AFTERNOON INTO FAR SOUTHERN MN AND NORTHERN IA THIS EVENING...AND FINALLY INTO SOUTHERN WISCONSIN AND NORTHERN ILLINOIS OVERNIGHT. GIVEN GOOD MODEL CONSENSUS HAVE RAISED PRECIPITATION CHANCES UP TOWARDS 100 SOUTH OF A LINE FROM AUSTIN MN TO RICHLAND CENTER WI. MOISTURE IS LIMITED...ON THE ORDER OF 1 G/KG...BUT THE STRONG FRONTOGENESIS SHOULD BE ABLE TO SQUEEZE OUT A TENTH OF LIQUID. WITH SNOW TO WATER RATIOS ON THE ORDER OF 15-20 TO 1...THIS WILL YIELD A QUICK 1 TO 2 INCHES OF SNOWFALL. FINALLY...IN THE WAKE OF THAT FRONTOGENESIS BAND...THAT SHORTWAVE TROUGH LOOKS TO BRING DOWN ANOTHER SURGE OF ARCTIC AIR WITH IT. 850MB TEMPS AFTER BRIEFLY CLIMBING TO -14 TO -18C AHEAD OF THE BAND...FALL TO -18 TO -22C BY 12Z WEDNESDAY. A TIGHTENING SURFACE PRESSURE GRADIENT SHOULD YIELD INCREASING NORTH WINDS...ADDING A WIND CHILL FACTOR. WIND CHILL ADVISORIES HAVE BEEN ISSUED...STARTING TAYLOR/CLARK AT 06Z AND THEN SOUTHEAST MN AND OTHER WI COUNTIES NORTH OF I-90 AT 10Z. THE WIND ON TOP OF THE NEW SNOW MAY PRODUCE SOME BLOWING AND DRIFTING ACROSS NORTHEAST IA TOO LATE IN THE NIGHT. CLEARING ALSO LOOKS TO ACCOMPANY THE CHILLY AIR. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 343 AM CST TUE DEC 10 2013 PLAN ON A COLD WEDNESDAY. ARCTIC AIR IS FORECAST TO GET DRAGGED INTO THE FORECAST AREA AS THE SHORTWAVE TROUGH OVER WESTERN IA HEADS EAST. TEMPS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...OR EVEN TO ZERO ACROSS TAYLOR/CLARK COUNTIES. ON TOP OF THE COLD...A DECENT PRESSURE GRADIENT IN PLACE SHOULD KEEP A NORTHWEST BREEZE GOING...RESULTING IN WIND CHILLS FROM THE -10 TO -30F RANGE. THESE COLD WIND CHILLS LOOK TO PERSIST INTO WEDNESDAY EVENING BEFORE WINDS TURN SOUTHWEST ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS PASSAGE. TEMPERATURES ARE FORECAST TO CLIMB AFTER MIDNIGHT IN RESPONSE TO THIS SOUTHWEST WIND...AS WELL AS INCREASING MID/HIGH CLOUDS. THESE CLOUDS ARE ASSOCIATED WITH ISENTROPIC LIFT WELL DOWNSTREAM OF A SHORTWAVE IN MONTANA. ONE QUESTION MARK IS IF ANY SNOW CAN FORM FROM THIS ISENTROPIC LIFT. MODELS HAVE BEEN GOING BACK AND FORTH ON THIS...WITH THE 10.00Z ECMWF AND GFS NOW BASICALLY DRY FOR WEDNESDAY NIGHT AND THURSDAY...WHEREAS THE 10.00Z CANADIAN MAINTAINS SOME LIGHT PRECIP OVER THE AREA BETWEEN 06-12Z THU. FOR NOW KEPT A 20 PERCENT CHANCE GOING BETWEEN 06-12Z THURSDAY OVER THE NORTHEAST PORTION OF THE AREA WITH DRY CONDITIONS BEFORE AND AFTER. WITH A WARM ADVECTION PATTERN IN PLACE THURSDAY...TEMPERATURES EXPECTED TO BE MUCH WARMER...ON THE ORDER OF 15-20 DEGREES. FROM THURSDAY NIGHT INTO FRIDAY...THE UPPER FLOW IS PROGGED TO BECOME MORE ZONAL OVER THE NORTHERN U.S.. WHAT THIS DOES IS ALLOWS A FRONTOGENESIS ZONE TO SET UP FROM THE DAKOTAS INTO WISCONSIN. THIS FRONTOGENESIS FORCING MAY RESULT IN SOME LIGHT SNOW THE ENTIRE TIME...WITH THE BEST CHANCES STAYING MAINLY NORTH OF THE FORECAST AREA. DID HONOR SOME 20 PERCENT CHANCES NORTH OF I-94 THURSDAY NIGHT PER MODEL CONSENSUS. ALSO ON FRIDAY...A SOUTHERN STREAM SHORTWAVE TROUGH IS SUGGESTED TO MOVE INTO THE CENTRAL PLAINS. FRONTOGENESIS DOWNSTREAM OF THIS SHORTWAVE TROUGH MAY SPREAD LIGHT PRECIP INTO SOUTHERN SECTIONS FOR THE FORECAST AREA. FOR NOW KEPT THIS PRECIP OUT...BUT SOMETHING TO MONITOR. THE SOUTHERN STREAM SYSTEM WILL NEED EVEN MORE MONITORING AS WE HEAD INTO FRIDAY NIGHT AND SATURDAY. MODELS ARE SUGGESTING AN INVERTED SURFACE TROUGH ASSOCIATED WITH THIS SHORTWAVE MOVING THROUGH THE FORECAST AREA. INVERTED TROUGHS ARE KNOWN TO BRING SNOW...SO PRECIPITATION CHANCES HAVE BEEN RAISED FOR FRIDAY NIGHT AND SATURDAY. IT SHOULD BE NOTED...THOUGH...THAT THE BULK OF THE ACCUMULATING SNOW LOOKS TO STAY SOUTHEAST OF THE AREA. ANOTHER BRIEF COOL DOWN...BUT NOT AS COLD AS SEEN RECENTLY...IS SUGGESTED FOR SUNDAY WITH DRY CONDITIONS AS HIGH PRESSURE MOVES THROUGH. LIGHT WARM ADVECTION SNOWS ARE PROGGED FOR MONDAY AS ANOTHER NORTHERN STREAM SHORTWAVE TROUGH DROPS DOWN TOWARDS THE UPPER MIDWEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY NOON) ISSUED AT 1136 AM CST TUE DEC 10 2013 GENERALLY GOOD VFR CONDITIONS EXPECTED THIS AFTERNOON. AWOS/ASOS UNITS ACROSS THE AREA CONTINUE TO REPORT MORE MVFR CIGS THAN ACTUALLY EXIST. SATELLITE IMAGERY AND SERIES OF WEB/SKY CAMS ACROSS THE AREA SHOW GENERALLY CLEAR SKIES OVER SOUTHEAST MN/WESTERN WI. SUBSIDING WINDS HAVE ALLOWED THE BLOWING SNOW TO LAY DOWN TOO. HOWEVER SOME DRIFTING LIKELY TO PERSIST AT SITES LIKE KRST UNTIL THE WEST-NORTHWEST WINDS STOP GUSTING. ANOTHER IN A FAST PARADE OF WEAK LOWS WILL TRACK ACROSS IA TONIGHT AND SPREAD ANOTHER ROUND OF -SN ACROSS THE TAF SITES. MAINLY IN THE 02Z-08Z PERIOD AT KRST AND 04-10Z AT KLSE AND MAINLY WITH MVFR CIGS/IFR VSBYS. BOTH SITES LOOK TO RECEIVE 1/2 TO 1 INCH OF FLUFFY SNOW. WINDS AGAIN INCREASE ONCE THE WEAK LOW PASSES...WITH NORTHWEST WINDS OF 10-20MPH AND GUSTY LATE TONIGHT/MUCH OF WED MORNING...TO ONCE AGAIN BLOW THE FRESH SNOW AROUND FOR A FEW HOURS. LOW CLOUDS EXPECTED TO DECREASE RATHER QUICKLY WED MORNING ONCE THE LOW PASSES...WITH WINDS DECREASING THRU WED AS THE NEXT WEAK HIGH BUILDS IN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR WIZ032>034-041>044. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST THURSDAY FOR WIZ017-029. MN...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR MNZ079- 086>088-094>096. IA...NONE. && $$ SHORT TERM...AJ LONG TERM....AJ AVIATION.....RRS