Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/09/13


AREA FORECAST DISCUSSION
NWS TAUNTON MA
1022 PM EST SUN DEC 8 2013 .SYNOPSIS... LOW PRESSURE LIFTING NORTH FROM THE MID ATLANTIC WILL BRING MIXED PRECIP LATE TONIGHT INTO 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 2 AM MONDAY MORNING/... 10 PM UPDATE... LOW LEVEL DRY AIR IS HOLDING BACK THE PRECIP SO WE DELAYED THE ONSET OF THE HIGHER POPS...WITH SNOW BEGINNING SOUTH OF THE MASS PIKE BETWEEN MIDNIGHT AND 2 AM...THEN SPREADING NORTH THROUGH 4 AM. REST OF FORECAST APPEARS ON TRACK. LATEST NAM STILL INDICATING POTENTIAL FOR MESOSCALE BANDING MOVING UP ALONG THE S COAST AND CAPE/ISLANDS 06-09Z AS STRONG 850 MB FRONTOGENESIS DEVELOPS WITHIN TIGHTENING THERMAL GRADIENT AND DECENT LIFT IN THE SNOW GROWTH REGION. HRRR ALSO SHOWING THIS POTENTIAL. HOWEVER...THIS IS THE TIME THE WARM NOSE ABOVE 800 MB MOVES IN SO PRECIP WILL LIKELY BE CHANGING TO SLEET DURING THIS TIME. IF IT REMAINED SNOW...POTENTIAL EXISTS FOR A QUICK INCH OR 2 THROUGH NEAR S COAST AND CAPE COD...BUT THE MORE LIKELY OUTCOME IS A COATING TO AN INCH BEFORE A CHANGE TO SLEET. && .SHORT TERM /2 AM MONDAY MORNING 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 CHALLENGES 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. A COATING TO PERHAPS 1 INCH OF SNOW IS POSSIBLE IN A FEW LOCATIONS. THERE ALSO IS A LOW PROBABILITY OF A BIT MORE SNOW THAN THAT 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 /03Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /THROUGH MONDAY/... MVFR-IFR CONDITIONS OVERSPREAD THE REGION AFT 04Z. PRECIPITATION SHOULD WORK IN FROM SOUTH TO NORTH ACROSS THE REST OF THE REGION BETWEEN 4Z AND 8Z. PTYPE STARTS AS SNOW THEN CHANGES TO SLEET AND FINALLY RAIN MON MORNING IN THE COASTAL PLAIN. INTERIOR TERMINALS WILL LIKELY HAVE TO DEAL WITH AN EXTENDED PERIOD OF FREEZING RAIN INTO THE AFTERNOON. CONDITIONS BEGIN TO IMPROVE INTO MONDAY NIGHT. KBOS TAF...MODERATE CONFIDENCE IN TAFS. LOW CONFIDENCE IN ONSET OF PRECIP AND TIMING OF PTYPE TRANSITIONS. KBDL TAF...MODERATE CONFIDENCE IN TAFS. LOW CONFIDENCE IN ONSET OF PRECIP AND TIMING OF PTYPE TRANSITIONS. 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 UNTIL 10 PM EST MONDAY FOR CTZ002. WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR CTZ003-004. MA...WINTER WEATHER ADVISORY UNTIL 10 PM EST MONDAY FOR MAZ002>004- 008>011-026. WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR MAZ005- 012>014-017. NH...WINTER WEATHER ADVISORY UNTIL 10 PM EST MONDAY FOR NHZ011-012- 015. RI...WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR RIZ001>004- 006. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EST MONDAY FOR ANZ231>234. SMALL CRAFT ADVISORY FROM 3 AM MONDAY TO 7 AM EST TUESDAY FOR ANZ235-237-254>256. SMALL CRAFT ADVISORY FROM 7 AM MONDAY TO 7 AM EST TUESDAY FOR ANZ250-251. && $$ SYNOPSIS...FRANK/SIPPRELL NEAR TERM...KJC/FRANK SHORT TERM...SIPPRELL LONG TERM...FRANK AVIATION...FRANK/SIPPRELL MARINE...FRANK/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
739 PM EST SUN DEC 8 2013 .SYNOPSIS... LOW PRESSURE LIFTING NORTH FROM THE MID ATLANTIC WILL BRING MIXED PRECIP LATE TONIGHT INTO 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 4 AM MONDAY MORNING/... 730 PM UPDATE... PREVIOUS FORECAST IS PRETTY MUCH ON TRACK. WE DID ADD A COATING TO 1 INCH OF SNOW POSSIBLE FOR EVEN THE OUTER-CAPE AND NANTUCKET. ITS PRETTY COLD RIGHT NOW AND DEWPOINTS ARE IN THE UPPER TEENS TO LOWER 20S...SO THINK THERE WILL BE SOME SNOW AT THE ONSET IN THIS REGION AS WELL. SNOW SHOULD OVERSPREAD THE REGION FROM SOUTH TO NORTH TONIGHT. EXPECT SNOW TO WORK INTO AREAS SOUTH OF THE MA TURNPIKE BETWEEN 9 PM AND 1 AM...THEN NORTH OF THAT REGION BETWEEN MIDNIGHT AND 4 AM. GENERALLY EXPECT AN INCH OR TWO OF SNOW ACROSS MOST OF THE REGION...BEFORE A CHANGE TO MIXED PRECIP. THE ONE THING WILL HAVE TO WATCH IS IF THERE IS ANY BANDING. THE LIFT DOES NOT LOOK AS ORGANIZED/INTENSE AS WHAT BROUGHT THE HEAVY SNOW TO THE MID ATLANTIC STATES THIS AFTERNOON. HOWEVER...SOME OF THE MESOSCALE MODELS HINT THERE COULD BE A BRIEF WINDOW FOR PERHAPS A BIT OF BANDING NEAR THE SOUTH COAST AFTER MIDNIGHT. WE UPDATED OUR SNOWFALL PROBABILITIES TO INDICATE A LOW PROBABILITY FOR THESE LOCATIONS REACHING OR EXCEEDING 2 INCHES OF SNOW. ALSO...A SPECIAL WEATHER STATEMENT WAS ISSUED FOR WHERE THERE IS NOT A WINTER WEATHER ADVISORY IN EFFECT. STILL EXPECT SLIPPERY TRAVEL OVERNIGHT INTO THE MON AM RUSH IN THIS REGION. && .SHORT TERM /4 AM MONDAY MORNING 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 CHALLENGES 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. A COATING TO PERHAPS 1 INCH OF SNOW IS POSSIBLE IN A FEW LOCATIONS. THERE ALSO IS A LOW PROBABILITY OF A BIT MORE SNOW THAN THAT 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 /00Z MONDAY 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/... MVFR-IFR CONDITIONS OVERSPREAD THE REGION AFTER 2 OR 3Z ALONG SOUTH COAST. PRECIPITATION SHOULD WORK IN FROM SOUTH TO NORTH ACROSS THE REST OF THE REGION BETWEEN 4Z AND 8Z. PTYPE STARTS AS SNOW THEN CHANGES TO SLEET AND FINALLY RAIN MON MORNING IN THE COASTAL PLAIN. INTERIOR TERMINALS WILL LIKELY HAVE TO DEAL WITH AN EXTENDED PERIOD OF FREEZING RAIN INTO THE AFTERNOON. CONDITIONS BEGIN TO IMPROVE INTO MONDAY NIGHT. KBOS TAF...MODERATE CONFIDENCE IN TAFS. LOW CONFIDENCE IN ONSET OF PRECIP AND TIMING OF PTYPE TRANSITIONS. KBDL TAF...MODERATE CONFIDENCE IN TAFS. LOW CONFIDENCE IN ONSET OF PRECIP AND TIMING OF PTYPE TRANSITIONS. 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 PM EST MONDAY FOR CTZ002. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY FOR CTZ003-004. MA...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 PM EST MONDAY FOR MAZ002>004-008>011-026. WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY FOR MAZ005-012>014-017. NH...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 10 PM EST MONDAY FOR NHZ011-012-015. RI...WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST MONDAY FOR RIZ001>004-006. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 PM EST MONDAY FOR ANZ231>234. SMALL CRAFT ADVISORY FROM 3 AM MONDAY TO 7 AM EST TUESDAY FOR ANZ235-237-254>256. SMALL CRAFT ADVISORY FROM 7 AM MONDAY TO 7 AM EST TUESDAY FOR ANZ250-251. && $$ SYNOPSIS...SIPPRELL/FRANK NEAR TERM...FRANK SHORT TERM...SIPPRELL LONG TERM...FRANK AVIATION...FRANK/SIPPRELL MARINE...SIPPRELL/FRANK
AREA FORECAST DISCUSSION
NWS NEW YORK NY
501 AM EST SAT DEC 7 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD TOWARDS THE REGION TODAY...AND DRIFT INTO NORTHERN NEW ENGLAND ON SUNDAY. LOW PRESSURE WILL APPROACH SUNDAY NIGHT AND IMPACT THE NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK. HIGH PRESSURE WILL BUILD IN FOR THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN BAND OF PCPN IS NOW OFFSHORE PER RADAR AND STLT. HAVE CANCELLED THE WINTER WX ADVY AS A RESULT. ONLY SOME RESIDUAL POCKETS OF LIGHT RAIN AND SNOW SHOWING UP ON RADAR AND VERIFIED BY OBS. SNOW HAS BEEN REPORTED DOWN TO KFRG AND KISP ON LI. FOLLOWED THE HRRR TIL 11Z FOR THE RESIDUAL LGT PCPN THIS MRNG. OTHERWISE...CLEARING SKIES AND NLY FLOW TODAY. EDGE OF THE CLOUD SHIELD WAS INVOF PORT JERVIS...AND ADVECTING EWD...AT 330 AM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... MODIFYING ARCTIC HI WILL BUILD OVER THE CWA TNGT. MSAS ANALYSIS AT 8Z PLACED THE 1044 CENTER OF THE HI OVER ERN MT. THIS WILL PRODUCE COLD TEMPS WITH WIDESPREAD TEENS EXPECTED ACROSS THE INTERIOR AND PINE BARRENS. STRONG SUBSIDENCE BUT A FEW HIGH CLOUDS ARE LIKELY TO FILTER IN FROM THE SW. AN INCREASING HIGH OVC CAN BE EXPECTED ON SUN WITH BACKING MID AND UPR LVL FLOW. CLOUDS WILL LOWER AND THICKEN IN THE AFTN. GFS TIME HEIGHTS SHOW LIFT IS FAIRLY ROBUST AFT 18Z...SO IT WILL JUST BE A MATTER OF HOW LONG IT TAKES FOR SATURATION AND PCPN...WHICH BASED ON THE 00Z SUITE OF DATA WILL BE ALL SNOW WITH PERHAPS SOME RAIN MIXED IN ON LI AND IN THE CITY. FCST HAS BEEN SPED UP WITH MOST SPOTS WITH CHCS FOR SNOW BY DARK. BASED ON THE CURRENT TIMING OF THE SYSTEM...LESS THAN AN INCH OF SNOW IS EXPECTED BY 5 PM. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A WINTRY MIX EXPECTED TO START THE WEEK AND THEN AN ARCTIC AIRMASS FOR MID TO LATE WEEK. WEATHER THROUGH THIS TIME PERIOD WILL BE CONTROLLED BY THE POLAR VORTEX OVER HUDSON BAY...WHICH WILL ROTATE A SERIES OF SHORTWAVES THROUGH THE NORTHERN US. MODELS IN DECENT AGREEMENT WITH ONE OF THESE SHORTWAVES PHASING WITH A SHORTWAVE EJECTING OUT OF THE WESTERN US...RESULTING IN A DEVELOPING LOW PRESSURE SYSTEM AFFECTING THE REGION WITH A WINTRY MIX OF PRECIP SUNDAY NIGHT INTO MONDAY MORNING. BASED ON CLOSLEY CLUSTERED CONSENSUS TRACK OF A DOUBLE BARRELED COASTAL LOW...A TRANSITION TO RAIN WOULD BE EXPECTED ALONG THE COAST BY MONDAY MORNING. ACROSS INTERIOR AREAS...PARTICULARLY NW ZONES...A FEW INCHES OF SNOW AND SLEET ARE POSSIBLE WITH EVEN A BRIEF TRANSITION TO FREEZING RAIN. SREF PLUMES INDICATING A MEAN OF 3 TO 4 INCHES ACROSS FAR NW ZONES...WITH GENERALLY AN INCH OR LESS FOR CITY COAST. THIS COULD MAKE FOR A WINTRY MORNING COMMUTE FOR INTERIOR AREAS...WHILE AT THE CITY/COAST ROADS SHOULD MAINLY BE WET WITH RAIN AND RISING TEMPS. MODELS ARE IN DECENT AGREEMENT WITH A TRAILING COLD FRONT PUSHING THROUGH THE REGION WITH DRYING CONDITIONS LATE MONDAY...BUT THE FRONT LINGERS CLOSE ENOUGH TO THE REGION MONDAY NIGHT INTO TUESDAY FOR ADDITIONAL WAVES OF LOW PRESSURE TO POSSIBLY BRUSH THE REGION WITH LIGHT WINTRY PRECIP. HAVE MAINTAINED SLIGHT CHANCE/CHANCE POPS THROUGH THIS TIME BASED ON MODEL SPREAD. THEN FOR THE MID TO LATE WEEK PERIOD...MODEL INDICATING SEVERAL PIECES OF AN ARCTIC AIRMASS OVER CANADA SPILLING INTO THE NORTHERN US. CURRENTLY HAVE TRENDED TEMPS TO STAY BELOW FREEZING FROM WEDNESDAY THRU FRIDAY BASED ON ANOMALOUSLY COLD AIRMASS...WITH POTENTIAL FOR TEMPS TO STRUGGLE TO REACH THE UPPER TEEN/LOWER 20S FOR HIGHS LATE WEEK IF POLAR VORTEX DROPS INTO NORTHERN NEW ENGLAND/SE CANADA AS DEPICTED BY SOME MODEL GUIDANCE. STAY TUNED. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... A WEAK WAVE OF LOW PRES WILL CONTINUE TO PUSH WELL OFFSHORE THIS MORNING WITH HIGH PRESSURE BUILDING INTO THE REGION THIS AFTERNOON THROUGH TONIGHT. MAIN PRECIP SHIELD HAS PUSHED OFFSHORE...WITH MAINLY JUST DRIZZLE AND ISOLATED LIGHT RASN SHOWERS EXPECTED THROUGH AROUND 10-12Z. WITH TEMPS AT FREEZING AT KSWF POTETNIAL EXISTS FOR -FZDZ THROUGH AROUND DAYBREAK. IFR/MVFR CONDS ARE EXPECTED TO GRADUALLY IMPROVE FROM W TO E AFTER 11-13Z...WITH VFR SHOULD RETURN TO ALL TERMINALS BY 15Z. MODERATE CONFIDENCE IN WIND FORECAST. ISOLD GUSTS AROUND 20 KT POSSIBLE AT KLGA/KEWR THROUGH EARLY MORNING. WINDS/GUSTS DIMINISH SAT AFTN/EVE. .OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY... .TONIGHT AND SUN...VFR. .SUN NIGHT...IFR. SNOW...THEN SNOW/SLEET/RAIN NEAR THE COAST AND SNOW/SLEET ACROSS INTERIOR. .MON...IFR. RAIN. WINTRY MIX ACROSS INTERIOR EARLY...THEN RAIN. SE WINDS 10-15 KT...BCMG NW LATE. .MON NIGHT...WINTRY MIX POSSIBLE. W WINDS AOB 10 KT. .TUE...VFR. W WINDS AOB 10 KT. .WED...VFR. W WIND 15-25 KT. && .MARINE... NLY FLOW WILL RESULT IN SCA CONDITIONS ON THE OCEAN TODAY. WINDS AND SEAS WILL LINGER A BIT LONGER OFF MONTAUK...SO THE SCA HAS BEEN EXTENDED THRU THE EVE FOR THE ERN MOST OCEAN ZONE. WINDS AND SEAS WILL REMAIN BLW SCA LVLS ON SUN WITH HIPRES OVER THE WATERS. SCA CONDITIONS LIKELY TO RETURN SUNDAY NIGHT INTO MONDAY MORNING ONTHE OCEAN AND LI SOUND WATERS...POSSIBLE ELSEWHERE...AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. WINDS SHOULD DIMINISH BY MONDAY AFTERNOON AS THE COMPLEX LOW PRESSURE SYSTEM WORKS THROUGH THE REGION...BUT OCEAN SEAS SHOULD REMAIN AT SCA LEVELS. MARGINAL SCA WINDS ARE POSSIBLE IN THE WAKE OF THE LOW MON NIGHT/EARLY TUE...MAINLY ON THE OCEAN. THE NEXT TIME OF CONCERN WILL BE TUESDAY NIGHT THROUGH WEDNESDAY WITH GALE CONDITIONS POSSIBLE AS AN ARCTIC FRONT CROSSES THE WATERS. && .HYDROLOGY... WIDESPREAD SIGNIFICANT PCPN IS NOT EXPECTED THRU THE DAY ON SUN. A STORM SYSTEM COULD BRING AROUND HALF INCH TO AN INCH LIQUID EQUIVALENT TO THE HYDROLOGIC SERVICE AREA...FROM LATE SUNDAY AFTERNOON THROUGH MONDAY NIGHT. && .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...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ353- 355. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ350. && $$ SYNOPSIS...JMC/NV NEAR TERM...JMC SHORT TERM...JMC LONG TERM...NV AVIATION...NV MARINE...JMC/NV HYDROLOGY...JMC/NV EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
414 AM EST SAT DEC 7 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD TOWARDS THE REGION TODAY...AND DRIFT INTO NORTHERN NEW ENGLAND ON SUNDAY. LOW PRESSURE WILL APPROACH SUNDAY NIGHT AND IMPACT THE NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK. HIGH PRESSURE WILL BUILD IN FOR THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN BAND OF PCPN IS NOW OFFSHORE PER RADAR AND STLT. HAVE CANCELLED THE WINTER WX ADVY AS A RESULT. ONLY SOME RESIDUAL POCKETS OF LIGHT RAIN AND SNOW SHOWING UP ON RADAR AND VERIFIED BY OBS. SNOW HAS BEEN REPORTED DOWN TO KFRG AND KISP ON LI. FOLLOWED THE HRRR TIL 11Z FOR THE RESIDUAL LGT PCPN THIS MRNG. OTHERWISE...CLEARING SKIES AND NLY FLOW TODAY. EDGE OF THE CLOUD SHIELD WAS INVOF PORT JERVIS...AND ADVECTING EWD...AT 330 AM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... MODIFYING ARCTIC HI WILL BUILD OVER THE CWA TNGT. MSAS ANALYSIS AT 8Z PLACED THE 1044 CENTER OF THE HI OVER ERN MT. THIS WILL PRODUCE COLD TEMPS WITH WIDESPREAD TEENS EXPECTED ACROSS THE INTERIOR AND PINE BARRENS. STRONG SUBSIDENCE BUT A FEW HIGH CLOUDS ARE LIKELY TO FILTER IN FROM THE SW. AN INCREASING HIGH OVC CAN BE EXPECTED ON SUN WITH BACKING MID AND UPR LVL FLOW. CLOUDS WILL LOWER AND THICKEN IN THE AFTN. GFS TIME HEIGHTS SHOW LIFT IS FAIRLY ROBUST AFT 18Z...SO IT WILL JUST BE A MATTER OF HOW LONG IT TAKES FOR SATURATION AND PCPN...WHICH BASED ON THE 00Z SUITE OF DATA WILL BE ALL SNOW WITH PERHAPS SOME RAIN MIXED IN ON LI AND IN THE CITY. FCST HAS BEEN SPED UP WITH MOST SPOTS WITH CHCS FOR SNOW BY DARK. BASED ON THE CURRENT TIMING OF THE SYSTEM...LESS THAN AN INCH OF SNOW IS EXPECTED BY 5 PM. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A WARM FRONT APPROACHES THE AREA INTO MONDAY. AS THE AREA OF LOW PRESSURE MOVES INTO SOUTHEAST CANADA...IT WILL PUSH A COLD FRONT ACROSS THE AREA. WITH ENOUGH COLD AIR IN PLACE...PRECIPITATION WILL POSSIBLY START OUT AS SNOW AND/OR SNOW CHANGING TO A WINTRY MIX SUNDAY NIGHT INTO EARLY MONDAY. AS WARMER AIR MOVES IN ON MONDAY...THE PRECIPITATION IS EXPECTED TO CHANGE OVER TO RAIN. THE FAR NORTHERN ZONES COULD HOLD ON THE WINTRY MIXTURE LONGER INTO MONDAY MORNING...BEFORE THE WARM AIR PUSHES THROUGH. AT THIS TIME...LIGHT SNOW/SLEET ACCUMULATIONS WOULD BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN AND WARMING TEMPERATURES. THE PRECIPITATION SHOULD COME TO AN END...AS THE SYSTEM MOVES OFFSHORE MONDAY NIGHT WITH A CHANCE OF LINGERING PRECIPITATION THROUGH TUESDAY MORNING AS A WEAK WAVE OF LOW PRESSURE SLIDES ACROSS THE AREA. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THE END OF THE EXTENDED PERIOD WITH DRY WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... A WEAK WAVE OF LOW PRES WILL CONTINUE TO PUSH WELL OFFSHORE THIS MORNING WITH HIGH PRESSURE BUILDING INTO THE REGION THIS AFTERNOON THROUGH TONIGHT. MAIN PRECIP SHIELD HAS PUSHED OFFSHORE...WITH MAINLY JUST DRIZZLE AND ISOLATED LIGHT RASN SHOWERS EXPECTED THROUGH AROUND 10-12Z. WITH TEMPS AT FREEZING AT KSWF POTETNIAL EXISTS FOR -FZDZ THROUGH AROUND DAYBREAK. IFR/MVFR CONDS ARE EXPECTED TO GRADUALLY IMPROVE FROM W TO E AFTER 11-13Z...WITH VFR SHOULD RETURN TO ALL TERMINALS BY 15Z. MODERATE CONFIDENCE IN WIND FORECAST. ISOLD GUSTS AROUND 20 KT POSSIBLE AT KLGA/KEWR THROUGH EARLY MORNING. WINDS/GUSTS DIMINISH SAT AFTN/EVE. .OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY... .TONIGHT AND SUN...VFR. .SUN NIGHT...IFR. SNOW...THEN SNOW/SLEET/RAIN NEAR THE COAST AND SNOW/SLEET ACROSS INTERIOR. .MON...IFR. RAIN. WINTRY MIX ACROSS INTERIOR EARLY...THEN RAIN. SE WINDS 10-15 KT...BCMG NW LATE. .MON NIGHT...WINTRY MIX POSSIBLE. W WINDS AOB 10 KT. .TUE...VFR. W WINDS AOB 10 KT. .WED...VFR. W WIND 15-25 KT. && .MARINE... NLY FLOW WILL RESULT IN SCA CONDITIONS ON THE OCEAN TODAY. WINDS AND SEAS WILL LINGER A BIT LONGER OFF MONTAUK...SO THE SCA HAS BEEN EXTENDED THRU THE EVE FOR THE ERN MOST OCEAN ZONE. WINDS AND SEAS WILL REMAIN BLW SCA LVLS ON SUN WITH HIPRES OVER THE WATERS. SCA CONDITIONS LIKELY TO RETURN SUNDAY NIGHT INTO MONDAY MORNING ONTHE OCEAN AND LI SOUND WATERS...POSSIBLE ELSEWHERE...AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. WINDS SHOULD DIMINISH BY MONDAY AFTERNOON AS THE COMPLEX LOW PRESSURE SYSTEM WORKS THROUGH THE REGION...BUT OCEAN SEAS SHOULD REMAIN AT SCA LEVELS. MARGINAL SCA WINDS ARE POSSIBLE IN THE WAKE OF THE LOW MON NIGHT/EARLY TUE...MAINLY ON THE OCEAN. THE NEXT TIME OF CONCERN WILL BE TUESDAY NIGHT THROUGH WEDNESDAY WITH GALE CONDITIONS POSSIBLE AS AN ARCTIC FRONT CROSSES THE WATERS. && .HYDROLOGY... WIDESPREAD SIGNIFICANT PCPN IS NOT EXPECTED THRU THE DAY ON SUN. A STORM SYSTEM COULD BRING AROUND HALF INCH TO AN INCH LIQUID EQUIVALENT TO THE HYDROLOGIC SERVICE AREA...FROM LATE SUNDAY AFTERNOON THROUGH MONDAY NIGHT. && .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...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ353- 355. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ350. && $$ SYNOPSIS...JMC/NV NEAR TERM...JMC SHORT TERM...JMC LONG TERM...NV AVIATION...NV MARINE...JMC/NV HYDROLOGY...JMC/NV EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
354 AM EST SAT DEC 7 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD TOWARDS THE REGION TODAY...AND DRIFT INTO NORTHERN NEW ENGLAND ON SUNDAY. LOW PRESSURE WILL APPROACH SUNDAY NIGHT AND IMPACT THE NORTHEAST THROUGH THE FIRST HALF OF NEXT WEEK. HIGH PRESSURE WILL BUILD IN FOR THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAIN BAND OF PCPN IS NOW OFFSHORE PER RADAR AND STLT. HAVE CANCELLED THE WINTER WX ADVY AS A RESULT. ONLY SOME RESIDUAL POCKETS OF LIGHT RAIN AND SNOW SHOWING UP ON RADAR AND VERIFIED BY OBS. SNOW HAS BEEN REPORTED DOWN TO KFRG AND KISP ON LI. FOLLOWED THE HRRR TIL 11Z FOR THE RESIDUAL LGT PCPN THIS MRNG. OTHERWISE...CLEARING SKIES AND NLY FLOW TODAY. EDGE OF THE CLOUD SHIELD WAS INVOF PORT JERVIS...AND ADVECTING EWD...AT 330 AM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... MODIFYING ARCTIC HI WILL BUILD OVER THE CWA TNGT. MSAS ANALYSIS AT 8Z PLACED THE 1044 CENTER OF THE HI OVER ERN MT. THIS WILL PRODUCE COLD TEMPS WITH WIDESPREAD TEENS EXPECTED ACROSS THE INTERIOR AND PINE BARRENS. STRONG SUBSIDENCE BUT A FEW HIGH CLOUDS ARE LIKELY TO FILTER IN FROM THE SW. AN INCREASING HIGH OVC CAN BE EXPECTED ON SUN WITH BACKING MID AND UPR LVL FLOW. CLOUDS WILL LOWER AND THICKEN IN THE AFTN. GFS TIME HEIGHTS SHOW LIFT IS FAIRLY ROBUST AFT 18Z...SO IT WILL JUST BE A MATTER OF HOW LONG IT TAKES FOR SATURATION AND PCPN...WHICH BASED ON THE 00Z SUITE OF DATA WILL BE ALL SNOW WITH PERHAPS SOME RAIN MIXED IN ON LI AND IN THE CITY. FCST HAS BEEN SPED UP WITH MOST SPOTS WITH CHCS FOR SNOW BY DARK. BASED ON THE CURRENT TIMING OF THE SYSTEM...LESS THAN AN INCH OF SNOW IS EXPECTED BY 5 PM. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... A WARM FRONT APPROACHES THE AREA INTO MONDAY. AS THE AREA OF LOW PRESSURE MOVES INTO SOUTHEAST CANADA...IT WILL PUSH A COLD FRONT ACROSS THE AREA. WITH ENOUGH COLD AIR IN PLACE...PRECIPITATION WILL POSSIBLY START OUT AS SNOW AND/OR SNOW CHANGING TO A WINTRY MIX SUNDAY NIGHT INTO EARLY MONDAY. AS WARMER AIR MOVES IN ON MONDAY...THE PRECIPITATION IS EXPECTED TO CHANGE OVER TO RAIN. THE FAR NORTHERN ZONES COULD HOLD ON THE WINTRY MIXTURE LONGER INTO MONDAY MORNING...BEFORE THE WARM AIR PUSHES THROUGH. AT THIS TIME...LIGHT SNOW/SLEET ACCUMULATIONS WOULD BE POSSIBLE...BUT PRIMARILY INLAND. WHATEVER LITTLE ACCUMULATION THE CITY/COAST COULD MANAGE WOULD BE WASHED AWAY FAIRLY QUICKLY BY RAIN AND WARMING TEMPERATURES. THE PRECIPITATION SHOULD COME TO AN END...AS THE SYSTEM MOVES OFFSHORE MONDAY NIGHT WITH A CHANCE OF LINGERING PRECIPITATION THROUGH TUESDAY MORNING AS A WEAK WAVE OF LOW PRESSURE SLIDES ACROSS THE AREA. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT THROUGH THE END OF THE EXTENDED PERIOD WITH DRY WEATHER...BUT WITH COLDER THAN NORMAL TEMPERATURES. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... AS A WEAK WAVE OF LOW PRES EXITS TO THE E OVERNIGHT...PRECIPITATION WILL COME TO AN END FROM NW TO SE. HIGH PRES BUILDS BACK IN ON SAT. P-TYPE IS ON THE VERGE OF CHANGING OVER TO -SN AT KSWF ALTHOUGH PRECIP IS COMING TO AN END. A DEEP MOIST COLUMN IS STILL EXPECTED TO PRODUCE DZ AND FZDZ AS TEMPS FALLING BELOW THE FREEZING MARK LATE. CLOSER TO THE COAST...RAIN WILL GENERALLY PREVAIL...BUT COULD MIX WITH -SNPL OR COMPLETELY CHANGEOVER TO -SN BRIEFLY BEFORE DRIER AIR ALOFT WORKS IN RESULTING IN DZ. FZDZ IS POSSIBLE LATE TONIGHT AT KHPN...BUT CONFIDENCE IN TEMP IS LOW AND THEREFORE HAVE LEFT AS PLAIN -DZ FOR NOW. THIS WILL BE MONITORED. GENERALLY EXPECT MVFR TO LOCALLY IFR CONDS THROUGH 10Z OR SO...THEN IMPROVING CONDS W TO E THEREAFTER. VFR SHOULD RETURN TO ALL TERMINALS BY 15Z. MODERATE CONFIDENCE IN WIND FORECAST. ISOLD GUSTS AROUND 20 KT POSSIBLE AT KLGA/KEWR THROUGH EARLY MORNING. WINDS/GUSTS DIMINISH SAT AFTN/EVE. .OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY... .SAT NIGHT AND SUN...VFR. .SUN NIGHT...IFR. SNOW...THEN SNOW/SLEET/RAIN NEAR THE COAST AND SNOW/SLEET ACROSS INTERIOR. .MON...IFR. RAIN. WINTRY MIX ACROSS INTERIOR EARLY...THEN RAIN. SE WINDS 10-15 KT...BCMG NW LATE. .MON NIGHT...WINTRY MIX POSSIBLE. W WINDS AOB 10 KT. .TUE...VFR. W WINDS AOB 10 KT. .WED...VFR. W WIND 15-25 KT. && .MARINE... NLY FLOW WILL RESULT IN SCA CONDITIONS ON THE OCEAN TODAY. WINDS AND SEAS WILL LINGER A BIT LONGER OFF MONTAUK...SO THE SCA HAS BEEN EXTENDED THRU THE EVE FOR THE ERN MOST OCEAN ZONE. WINDS AND SEAS WILL REMAIN BLW SCA LVLS ON SUN WITH HIPRES OVER THE WATERS. && .HYDROLOGY... WIDESPREAD SIGNIFICANT PCPN IS NOT EXPECTED THRU THE DAY ON SUN. A STORM SYSTEM COULD BRING AROUND HALF INCH TO AN INCH LIQUID EQUIVALENT TO THE HYDROLOGIC SERVICE AREA...FROM LATE SUNDAY AFTERNOON THROUGH MONDAY NIGHT. && .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...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ353- 355. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ350. && $$ SYNOPSIS...JMC NEAR TERM...JMC SHORT TERM...JMC LONG TERM...FIG AVIATION... MARINE...JMC/NV HYDROLOGY...JMC/FIG EQUIPMENT...
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
1012 PM EST SUN DEC 8 2013 .EVENING UPDATE... CURRENT TEMPS ACROSS THE AREA WILL BE VERY CLOSE TO THE OVERNIGHT LOWS AS AREA TEMPS REMAIN NEARLY UNCHANGED INTO THE EARLY MONDAY MORNING HOURS... WHEN TEMPS SHOULD BEGIN TO WARM SLIGHTLY FROM THE SOUTH AS THE WARM FRONT CREEPS NORTH. RADAR SHOWS AN AREA OF RAIN CONTINUING TO TRAIN ACROSS NORTH GA... AND ALTHO THIS AREA MAY SAG SLIGHTLY MORE TO THE SOUTH AND EAST OVERNIGHT... STILL EXPECT THE GREATER RAIN CHANCES AND QPF TOTALS TO BE MAINLY FOCUSED ACROSS AREAS GENERALLY ALONG AND NORTH OF A FRANKLIN TO ATLANTA TO GAINSVILLE LINE. RAINFALL TOTALS SO FAR OVER THE LAST 12 HOURS SHOW A LARGE SWATH OF 1.00 TO 1.5 INCHES CENTERED NEAR A LINE FROM NEAR ROME TO ELLIJAY. THIS AREA COULD SEE ANOTHER INCH OVERNIGHT... AND WILL LIKELY PUSH MOST STREAMS TO NEAR OR ABOVE AT LEAST CAUTION STAGE BY MORNING...WITH A FEW ISOLATED STREAMS POSSIBLY FLIRTING WITH MINOR FLOOD. HOWEVER... STILL NOT EXPECTING WIDESPREAD FLOOD PROBLEMS AS THE RAIN IS GENERALLY LIGHT... AND NOT RESULTING HEAVY RUNOFF AT THIS TIME. HOWEVER... THE STEADY RAIN WILL WARRANT MONITORING RIVERS AND STREAMS ACROSS NORTH GA CLOSELY OVERNIGHT. HAVE TWEAKED TEMPS AND POPS FOR TONIGHT TO MATCH CURRENT TRENDS. ALTHOUGH CANNOT RULE OUT AN ELEVATED RUMBLE OF THUNDER... HAVE REMOVED ANY WORDING FOR THUNDER FOR THE REST OF TONIGHT AS EXPECT THIS GREATER POTENTIAL TO BE OVER CENTRAL AND SOUTH AL FOR THE REST OF TONIGHT. /39 .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... /ISSUED AT 230 PM EST SUN DEC 8 2013/ HIGH PRESSURE WEDGE CONTINUES ACROSS MUCH OF GEORGIA THIS AFTERNOON. A WARM FRONT IS ALSO SITUATED RIGHT ALONG THE GA/FLORIDA BORDER. SOME CLEARING HAS OCCURRED ACROSS THE NORTHERN FLORIDA PANHANDLE/SOUTH GA...AND MAY MAKE IT INTO THE SW CORNER OF THE CWFA. HAVE TWEAKED THE CLOUD COVER FOR THE NEXT FEW HOURS...BUT THE CLOUDS ARE EXPECTED TO FILL BACK IN OVERNIGHT. REGIONAL RADAR PIC DOES SHOW A SHORTWAVE ACROSS SE MS/SW AL ENHANCING CONVECTION THIS AFTERNOON. THIS FEATURE MAY HELP PRODUCE A FEW THUNDERSTORMS ACROSS THE NW CWFA LATER THIS EVENING. MIN/MAX TEMPS FOR OVERNIGHT AND MONDAY WILL DEPEND HEAVILY UPON THE NORTHWARD PROGRESSION OF THE WARM FRONT. NOT AT ALL CONFIDENT THAT THE BOUNDARY WILL MOVE MUCH FURTHER NORTH THAN THE SOUTHERN CWFA OVERNIGHT. BL WINDS ARE NOT CONDUCIVE...PLUS ANY PRECIP FALLING WILL HELP RE-ENFORCE THE COOLER WEDGE OVERNIGHT. NORTHWARD PROGRESSION OF THE WARM FRONT/EROSION OF THE WEDGE IS MORE LIKELY ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST. MORNING LOW CLOUDS/FOG/DRIZZLE WILL GIVE WAY TO MORE WIDESPREAD RAINS AS THE FRONT MOVES THROUGH. OVER THE PAST FEW DAYS...THE MODELS HAVE CONTINUED TO SHIFT THE HEAVY RAINFALL AXIS NORTHWARD. THIS SEEMS REASONABLE IN CORRELATION WITH THE CURRENT REGIONAL RADAR PIC. THE NW CORNER OF THE CWFA SHOULD PICK UP THE MOST RAINFALL...GENERALLY AROUND 2 INCHES EXPECTED. HOWEVER...ISOLATED SPOTS MAY RECEIVE HIGHER AMOUNTS. HAVE OPTED NOT TO RAISE A FLOOD WATCH AT THIS TIME. NLISTEMAA .LONG TERM /TUESDAY THROUGH SUNDAY/... /ISSUED AT 230 PM EST SUN DEC 8 2013/ MEDIUM RANGE MODEL TRENDS CONTINUE TO SHOW NO SIGNIFICANT DEPARTURES FROM THE PREVIOUS RUN WITH THE UPPER-LEVEL PATTERN REMAINING FAIRLY PROGRESSIVE AND MODERATE IN AMPLITUDE. BEST COLD AIR WITH THIS PATTERN REMAINS WELL NORTH OF THE STATE...WITH NEAR SEASONALLY NORMAL TEMPERATURES EXPECTED. NO SUBSTANTIAL CHANGES WERE MADE TO THE EXISTING EXTENDED FORECAST GRIDS...SEE PREVIOUS LONG TERM FORECAST DISCUSSION BELOW. 20 PREV LONG TERM DISCUSSION/TUESDAY THROUGH SATURDAY/... UPPER TROUGH AXIS IS PUSHING THROUGH THE EASTERN THIRD OF THE COUNTRY AS WE BEGIN THE EXTENDED...WITH MOST PRECIP MOVING OUT OF THE SOUTHEAST BY LATE TUESDAY. GFS AND ECMWF ARE IN FAIRLY GOOD AGREEMENT THROUGH THE FIRST PART OF THE PERIOD. ELONGATED FRONT SHOULD STALL ACROSS SOUTH GEORGIA OR NORTHERN FLORIDA WHICH WILL KEEP SLIGHT CHANCE POPS ACROSS SOUTHERN ZONES BUT FOR THE MOST PART THE MIDDLE PART OF THE WEEK SHOULD BE DRY...ALBEIT COOL WITH THE PASSAGE OF THE FRONT /ALTHOUGH EVEN THAT IS RELATIVE... EXPECTING AVERAGE TO JUST SLIGHTLY BELOW AVERAGE TEMPS SO NOT PARTICULARLY COOL FOR THIS TIME OF YEAR...JUST COOLER THAN MONDAY TEMPS/. A REINFORCING WAVE AND MAINLY DRY COLD FRONT PUSHES THROUGH WEDNESDAY NIGHT WITH A COLDER SURFACE HIGH SLIDING SOUTHEAST FROM THE NORTHERN PLAINS...SO THURSDAY TEMPS SHOULD BE JUST A TAD COOLER THAN WEDNESDAY. WEAK RIDGING BUILDS IN ALOFT THURSDAY NIGHT INTO FRIDAY WITH AN INCREMENTAL INCREASE IN TEMPS IN ADVANCE OF A STRONG SHORTWAVE OVER THE DESERT SOUTHWEST. AS THIS MOVES INTO THE SOUTHERN PLAINS...IT SHOULD INDUCE SURFACE LOW DEVELOPMENT IN THE NORTHWEST GULF. THIS IS WHERE THE GFS AND ECMWF BEGIN TO REALLY DIVERGE. THE GFS HAS ONE MAIN SYSTEM AND BEGINS OVERSPREADING PRECIP ACROSS THE SOUTHEAST FRIDAY NIGHT. THE ECMWF HAS A WEAK SHORTWAVE LIFTING INTO THE PLAINS FRIDAY NIGHT...BRINGING LIGHT PRECIP TO THE SOUTHEAST OVER THE WEEKEND...BUT HOLDS OFF ON THE MAIN SYSTEM UNTIL AFTER THE END OF THE PERIOD. SO...SATURDAY COULD BE REALLY WET /AS PER THE GFS/...OR IT COULD JUST BE A LITTLE WET /AS PER THE ECMWF/. AS IS TYPICAL FOR THAT FAR OUT AND PLAYED THE MIDDLE OF THE ROAD BY PAINTING CHANCE POPS EVERYWHERE. STAY TUNED FOR LATER FORECASTS. TDP && .AVIATION... /ISSUED AT 640 PM EST SUN DEC 8 2013/ 00Z UPDATE... A VERY MOIST AND MODERATELY UNSTABLE SW MID LEVEL FLOW WILL CONTINUE TO OVERRUN THE COOL RIDGE OF HIGH PRESSURE AT THE SURFACE TO PRODUCE LIFR CIGS AND 1-3SM -RADZ BR OVERNIGHT. RADAR SHOWS A BAND OF RAIN SHOWERS SPREADING IN ACROSS NORTH GA AND THE HRRR MODEL SPREADS THIS AREA OF RAIN INTO ATL BY 09Z TONIGHT...WHILE THE OTHER MODELS HOLD THE HEAVIEST RAIN TO THE NORTH. WILL SHOW -RADZ OVERNIGHT WITH AREAS OF -RA EXPECTED TO PERSIST ON MON. THIS WILL HELP HOLD PREVAILING CIGS DOWN AROUND IFR LEVELS ON MON. CURRENT 10KT EAST WIND WILL VEER SE AND DIMINISH TO AROUND 5KTS BY 09Z... SSW BY 15-17Z MON...THEN WNW BY 21Z WITH SPEEDS AROUND 7-8KTS MON AFTERNOON. EXPECT FRONTAL PASSAGE AT ATL BY 00Z TUE WITH INCREASING NW WINDS. //ATL CONFIDENCE...00Z UPDATE... HIGH CONFIDENCE ON ALL ELEMENTS... EXCEPT MEDIUM CONFIDENCE ON IFR CIGS PREVAILING MONDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 41 59 49 57 / 70 80 50 60 ATLANTA 46 59 46 53 / 70 80 60 50 BLAIRSVILLE 41 50 41 52 / 100 90 70 60 CARTERSVILLE 46 54 42 50 / 90 90 80 50 COLUMBUS 56 70 56 62 / 40 80 50 50 GAINESVILLE 40 53 46 53 / 80 80 70 60 MACON 50 68 57 63 / 30 50 40 50 ROME 47 51 42 49 / 90 90 80 50 PEACHTREE CITY 48 63 48 55 / 60 80 50 50 VIDALIA 55 73 62 70 / 20 30 30 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...NLISTEMAA/39 LONG TERM....20 AVIATION...39
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
640 PM EST SUN DEC 8 2013 .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... /ISSUED AT 230 PM EST SUN DEC 8 2013/ HIGH PRESSURE WEDGE CONTINUES ACROSS MUCH OF GEORGIA THIS AFTERNOON. A WARM FRONT IS ALSO SITUATED RIGHT ALONG THE GA/FLORIDA BORDER. SOME CLEARING HAS OCCURRED ACROSS THE NORTHERN FLORIDA PANHANDLE/SOUTH GA...AND MAY MAKE IT INTO THE SW CORNER OF THE CWFA. HAVE TWEAKED THE CLOUD COVER FOR THE NEXT FEW HOURS...BUT THE CLOUDS ARE EXPECTED TO FILL BACK IN OVERNIGHT. REGIONAL RADAR PIC DOES SHOW A SHORTWAVE ACROSS SE MS/SW AL ENHANCING CONVECTION THIS AFTERNOON. THIS FEATURE MAY HELP PRODUCE A FEW THUNDERSTORMS ACROSS THE NW CWFA LATER THIS EVENING. MIN/MAX TEMPS FOR OVERNIGHT AND MONDAY WILL DEPEND HEAVILY UPON THE NORTHWARD PROGRESSION OF THE WARM FRONT. NOT AT ALL CONFIDENT THAT THE BOUNDARY WILL MOVE MUCH FURTHER NORTH THAN THE SOUTHERN CWFA OVERNIGHT. BL WINDS ARE NOT CONDUCIVE...PLUS ANY PRECIP FALLING WILL HELP RE-ENFORCE THE COOLER WEDGE OVERNIGHT. NORTHWARD PROGRESSION OF THE WARM FRONT/EROSION OF THE WEDGE IS MORE LIKELY ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST. MORNING LOW CLOUDS/FOG/DRIZZLE WILL GIVE WAY TO MORE WIDESPREAD RAINS AS THE FRONT MOVES THROUGH. OVER THE PAST FEW DAYS...THE MODELS HAVE CONTINUED TO SHIFT THE HEAVY RAINFALL AXIS NORTHWARD. THIS SEEMS REASONABLE IN CORRELATION WITH THE CURRENT REGIONAL RADAR PIC. THE NW CORNER OF THE CWFA SHOULD PICK UP THE MOST RAINFALL...GENERALLY AROUND 2 INCHES EXPECTED. HOWEVER...ISOLATED SPOTS MAY RECEIVE HIGHER AMOUNTS. HAVE OPTED NOT TO RAISE A FLOOD WATCH AT THIS TIME. NLISTEMAA .LONG TERM /TUESDAY THROUGH SUNDAY/... /ISSUED AT 230 PM EST SUN DEC 8 2013/ MEDIUM RANGE MODEL TRENDS CONTINUE TO SHOW NO SIGNIFICANT DEPARTURES FROM THE PREVIOUS RUN WITH THE UPPER-LEVEL PATTERN REMAINING FAIRLY PROGRESSIVE AND MODERATE IN AMPLITUDE. BEST COLD AIR WITH THIS PATTERN REMAINS WELL NORTH OF THE STATE...WITH NEAR SEASONALLY NORMAL TEMPERATURES EXPECTED. NO SUBSTANTIAL CHANGES WERE MADE TO THE EXISTING EXTENDED FORECAST GRIDS...SEE PREVIOUS LONG TERM FORECAST DISCUSSION BELOW. 20 PREV LONG TERM DISCUSSION/TUESDAY THROUGH SATURDAY/... UPPER TROUGH AXIS IS PUSHING THROUGH THE EASTERN THIRD OF THE COUNTRY AS WE BEGIN THE EXTENDED...WITH MOST PRECIP MOVING OUT OF THE SOUTHEAST BY LATE TUESDAY. GFS AND ECMWF ARE IN FAIRLY GOOD AGREEMENT THROUGH THE FIRST PART OF THE PERIOD. ELONGATED FRONT SHOULD STALL ACROSS SOUTH GEORGIA OR NORTHERN FLORIDA WHICH WILL KEEP SLIGHT CHANCE POPS ACROSS SOUTHERN ZONES BUT FOR THE MOST PART THE MIDDLE PART OF THE WEEK SHOULD BE DRY...ALBEIT COOL WITH THE PASSAGE OF THE FRONT /ALTHOUGH EVEN THAT IS RELATIVE... EXPECTING AVERAGE TO JUST SLIGHTLY BELOW AVERAGE TEMPS SO NOT PARTICULARLY COOL FOR THIS TIME OF YEAR...JUST COOLER THAN MONDAY TEMPS/. A REINFORCING WAVE AND MAINLY DRY COLD FRONT PUSHES THROUGH WEDNESDAY NIGHT WITH A COLDER SURFACE HIGH SLIDING SOUTHEAST FROM THE NORTHERN PLAINS...SO THURSDAY TEMPS SHOULD BE JUST A TAD COOLER THAN WEDNESDAY. WEAK RIDGING BUILDS IN ALOFT THURSDAY NIGHT INTO FRIDAY WITH AN INCREMENTAL INCREASE IN TEMPS IN ADVANCE OF A STRONG SHORTWAVE OVER THE DESERT SOUTHWEST. AS THIS MOVES INTO THE SOUTHERN PLAINS...IT SHOULD INDUCE SURFACE LOW DEVELOPMENT IN THE NORTHWEST GULF. THIS IS WHERE THE GFS AND ECMWF BEGIN TO REALLY DIVERGE. THE GFS HAS ONE MAIN SYSTEM AND BEGINS OVERSPREADING PRECIP ACROSS THE SOUTHEAST FRIDAY NIGHT. THE ECMWF HAS A WEAK SHORTWAVE LIFTING INTO THE PLAINS FRIDAY NIGHT...BRINGING LIGHT PRECIP TO THE SOUTHEAST OVER THE WEEKEND...BUT HOLDS OFF ON THE MAIN SYSTEM UNTIL AFTER THE END OF THE PERIOD. SO...SATURDAY COULD BE REALLY WET /AS PER THE GFS/...OR IT COULD JUST BE A LITTLE WET /AS PER THE ECMWF/. AS IS TYPICAL FOR THAT FAR OUT AND PLAYED THE MIDDLE OF THE ROAD BY PAINTING CHANCE POPS EVERYWHERE. STAY TUNED FOR LATER FORECASTS. TDP && .AVIATION... 00Z UPDATE... A VERY MOIST AND MODERATELY UNSTABLE SW MID LEVEL FLOW WILL CONTINUE TO OVERRUN THE COOL RIDGE OF HIGH PRESSURE AT THE SURFACE TO PRODUCE LIFR CIGS AND 1-3SM -RADZ BR OVERNIGHT. RADAR SHOWS A BAND OF RAIN SHOWERS SPREADING IN ACROSS NORTH GA AND THE HRRR MODEL SPREADS THIS AREA OF RAIN INTO ATL BY 09Z TONIGHT...WHILE THE OTHER MODELS HOLD THE HEAVIEST RAIN TO THE NORTH. WILL SHOW -RADZ OVERNIGHT WITH AREAS OF -RA EXPECTED TO PERSIST ON MON. THIS WILL HELP HOLD PREVAILING CIGS DOWN AROUND IFR LEVELS ON MON. CURRENT 10KT EAST WIND WILL VEER SE AND DIMINISH TO AROUND 5KTS BY 09Z... SSW BY 15-17Z MON...THEN WNW BY 21Z WITH SPEEDS AROUND 7-8KTS MON AFTERNOON. EXPECT FRONTAL PASSAGE AT ATL BY 00Z TUE WITH INCREASING NW WINDS. //ATL CONFIDENCE...00Z UPDATE... HIGH CONFIDENCE ON ALL ELEMENTS... EXCEPT MEDIUM CONFIDENCE ON IFR CIGS PREVAILING MONDAY AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 41 59 49 57 / 70 80 50 60 ATLANTA 46 59 46 53 / 70 80 60 50 BLAIRSVILLE 41 50 41 52 / 100 90 70 60 CARTERSVILLE 46 54 42 50 / 90 90 80 50 COLUMBUS 56 70 56 62 / 40 80 50 50 GAINESVILLE 40 53 46 53 / 80 80 70 60 MACON 50 68 57 63 / 30 50 40 50 ROME 47 51 42 49 / 90 90 80 50 PEACHTREE CITY 48 63 48 55 / 60 80 50 50 VIDALIA 55 73 62 70 / 20 30 30 50 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...NLISTEMAA/39 LONG TERM....20 AVIATION...39
AREA FORECAST DISCUSSION
NWS POCATELLO ID
428 AM MST SAT DEC 7 2013 .UPDATE...UPON FURTHER INSPECTION OF TEMPS AND WINDS WE DECIDED TO ISSUE A WIND CHILL WARNING FOR UPPER SNAKE RIVER PLAIN FOR TONIGHT THROUGH TOMORROW MORNING. WINDS WILL REMAIN BREEZY AS THIS UPPER LOW MOVES EAST...AND WITH A NORTHERLY FLOW BEHIND IT TEMPERATURES WILL BEGIN TO PLUNGE ONCE AGAIN. WIND CHILL VALUES OF -15 TO -25 ARE LIKELY IN THIS AREA. MANY OTHER AREAS IN SE ID WILL LIKELY REACH WIND CHILL VALUES OF AT LEAST -10. && .PREV DISCUSSION... /ISSUED 254 AM MST SAT DEC 7 2013/ SHORT TERM...TODAY THROUGH SUNDAY. WATER VAPOR IMAGERY SHOWS AN UPPER LOW POSITIONED OVER CENTRAL OREGON EARLY THIS MORNING WITH A GOOD PUSH OF MOISTURE STREAMING NORTH INTO IDAHO. AS THIS LOW MOVES EAST...SE ID WILL SEE SNOW THROUGH THE DAY TODAY WITH THE CENTRAL MOUNTAINS ALREADY RECEIVING SNOW. WITH THE COLDER TEMPERATURES THAT HAVE SET IN... SNOW RATIOS ARE EXPECTED TO BE AROUND 20 TO 1 MEANING WE WILL HAVE VERY LIGHT FLUFFY SNOW. EXPECTING WINDS TO PICK UP WITH GUSTS AROUND 25 MPH IN THE EASTERN MAGIC VALLEY... LOWER SNAKE HIGHLANDS... SOUTH CENTRAL HIGHLANDS AND CARIBOU HIGHLANDS SO MADE MENTION OF SOME BLOWING SNOW TO GO WITH THE WINTER WEATHER ADVISORY CURRENTLY IN EFFECT. THE HRRR IS SHOWING THE BIGGEST PUSH OF SNOWFALL AFTER 11 AM TODAY WHICH IS PRETTY IN LINE WITH THE NAM. THROUGH SUNDAY MORNING... VALLEY SITES COULD SEE 1 TO 4 INCHES AND MOUNTAIN AREAS COULD SEE 4 TO 8 INCHES WITH SOME HIGHEST PEAKS SEEING 9 INCHES OF NEW SNOW. SNOWFALL WILL BEGIN TAPERING OFF SUNDAY MORNING. EP LONG TERM...MONDAY THROUGH SATURDAY. NORTHERLY FLOW WILL PERSIST INTO MIDWEEK WHEN THE FLOW BECOMES NORTHWESTERLY. THE EXTREME COLD WILL PERSIST INTO MIDWEEK. TEMPS WILL WARM WHEN THE FLOW BEGINS TO TURN. SOME WEAK SHORTWAVE TROUGHS WILL MOVE THROUGH THE REGION WHICH COULD KICK OFF AN ISOLATED SNOW SHOWER IN THE MOUNTAINS AND HIGHLANDS FOR THE FIRST PART OF THE WEEK. MODELS HAVE CHANGED DRASTICALLY WITH THE HANDLING OF THE NEXT SYSTEM ARRIVING LATER IN THE WEEK. GENERALLY...THE MODELS HAVE WEAKENED THIS SYSTEM SUBSTANTIALLY. HAVE LOWERED PRECIPITATION CHANCES SOME GIVEN THE CHANGE...BUT STILL CONTINUING TO MENTION SOME SNOW IN CASE THE MODELS FLIP FLOP. TEMPS WILL CONTINUE TO WARM INTO LATE WEEK AND COULD BE CLOSER TO NORMAL BY THE END OF THE WEEK. VALLE AVIATION...A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION TODAY. EXPECT WIDESPREAD SNOW ACROSS MUCH OF THE AREA. REDUCED CEILINGS AND VISIBILITIES ARE A GOOD BET TODAY. CONDITIONS WILL IMPROVE TONIGHT...ESPECIALLY OVERNIGHT. VALLE && .PIH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING IDZ017-021. WIND CHILL WARNING FROM 11 PM THIS EVENING TO 11 AM MST SUNDAY IDZ020. WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING IDZ022>025. && $$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
254 AM MST SAT DEC 7 2013 .SHORT TERM...TODAY THROUGH SUNDAY. WATER VAPOR IMAGERY SHOWS AN UPPER LOW POSITIONED OVER CENTRAL OREGON EARLY THIS MORNING WITH A GOOD PUSH OF MOISTURE STREAMING NORTH INTO IDAHO. AS THIS LOW MOVES EAST...SE ID WILL SEE SNOW THROUGH THE DAY TODAY WITH THE CENTRAL MOUNTAINS ALREADY RECEIVING SNOW. WITH THE COLDER TEMPERATURES THAT HAVE SET IN... SNOW RATIOS ARE EXPECTED TO BE AROUND 20 TO 1 MEANING WE WILL HAVE VERY LIGHT FLUFFY SNOW. EXPECTING WINDS TO PICK UP WITH GUSTS AROUND 25 MPH IN THE EASTERN MAGIC VALLEY... LOWER SNAKE HIGHLANDS... SOUTH CENTRAL HIGHLANDS AND CARIBOU HIGHLANDS SO MADE MENTION OF SOME BLOWING SNOW TO GO WITH THE WINTER WEATHER ADVISORY CURRENTLY IN EFFECT. THE HRRR IS SHOWING THE BIGGEST PUSH OF SNOWFALL AFTER 11 AM TODAY WHICH IS PRETTY IN LINE WITH THE NAM. THROUGH SUNDAY MORNING... VALLEY SITES COULD SEE 1 TO 4 INCHES AND MOUNTAIN AREAS COULD SEE 4 TO 8 INCHES WITH SOME HIGHEST PEAKS SEEING 9 INCHES OF NEW SNOW. SNOWFALL WILL BEGIN TAPERING OFF SUNDAY MORNING. EP .LONG TERM...MONDAY THROUGH SATURDAY. NORTHERLY FLOW WILL PERSIST INTO MIDWEEK WHEN THE FLOW BECOMES NORTHWESTERLY. THE EXTREME COLD WILL PERSIST INTO MIDWEEK. TEMPS WILL WARM WHEN THE FLOW BEGINS TO TURN. SOME WEAK SHORTWAVE TROUGHS WILL MOVE THROUGH THE REGION WHICH COULD KICK OFF AN ISOLATED SNOW SHOWER IN THE MOUNTAINS AND HIGHLANDS FOR THE FIRST PART OF THE WEEK. MODELS HAVE CHANGED DRASTICALLY WITH THE HANDLING OF THE NEXT SYSTEM ARRIVING LATER IN THE WEEK. GENERALLY...THE MODELS HAVE WEAKENED THIS SYSTEM SUBSTANTIALLY. HAVE LOWERED PRECIPITATION CHANCES SOME GIVEN THE CHANGE...BUT STILL CONTINUING TO MENTION SOME SNOW IN CASE THE MODELS FLIP FLOP. TEMPS WILL CONTINUE TO WARM INTO LATE WEEK AND COULD BE CLOSER TO NORMAL BY THE END OF THE WEEK. VALLE && .AVIATION...A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION TODAY. EXPECT WIDESPREAD SNOW ACROSS MUCH OF THE AREA. REDUCED CEILINGS AND VISIBILITIES ARE A GOOD BET TODAY. CONDITIONS WILL IMPROVE TONIGHT...ESPECIALLY OVERNIGHT. VALLE && .PIH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING IDZ017-021. WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING IDZ022>025. && $$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
111 PM EST SAT DEC 7 2013 .SYNOPSIS... THE FRONT WILL THEN PUSH FARTHER SOUTH TO OFF THE GEORGIA COAST LATER TODAY INTO SUNDAY MORNING...AS COLD HIGH PRESSURE BUILDS FROM THE UPPER MIDWEST TO THE EASTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE NORTHEAST JUST WEST OF THE APPALACHIANS SUNDAY INTO MONDAY MORNING...WHILE A SECOND LOW PRESSURE AREA TRACKS NORTHEAST JUST OFF THE MID ATLANTIC COAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT CONTINUES TO PUSH WELL SOUTH OF THE AREA. THE ONLY RAIN LEFT IS MAINLY OVER NORTHEAST NORTH CAROLINA. THIS SHOULD PUSH TO THE SOUTH OF THE AREA IN THE NEXT COUPLE OF AREAS. THIS FOLLOWS THE HRRR DEPICTION OF THE ECHOS. WITH THE CONTINUED NORTHEAST EXCEPT ACRS THE FAR NORTH...EXPECT SKIES TO REMAIN CLOUDY/MOSTLY CLOUDY AS LOW LEVEL N/NE FLOW TENDS TO KEEP IN THE LOW LEVEL MOISTURE EVEN AS BULK OF THE COLUMN DRIES OUT. LIKE THE GRIDDED LAMP TEMPS WHICH KEEP TEMPERATURES VERY STEADY THROUGH THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... N-NE SFC WINDS WILL CONTINUE TO FUNNEL COLDER AIR INTO THE MID ATLC REGION TONIGHT...SETTING THE THE STAGE FOR THE WINTER PRECIP EVENT SUN. JUST S CHC FOR LIGHT RAIN ACRS THE FAR SOUTH THIS EVENING...OTHERWISE PARTLY TO MOSTLY CLOUDY WITH LOWS IN THE MID- UPPER 20S N TO THE MID-UPPER 30S SE. HEADLINE-WISE...ONLY CHANGE HAS BEEN TO ADD MECKLENBURG COUNTY TO THE WATCH. PER COORDINATION W/ SURROUNDING OFFICES AND BASED ON LATEST THINKING...THERE REMAINS A LOT OF UNCERTAINTY IN QPF AMOUNTS AND SUBSEQUENT ICE ACCUMULATION ESPECIALLY AREAS SOUTH OF FARMVILLE. ALSO DID RAISE AN ADVSY YET AS THIS IS MAINLY STILL 3RD PERIOD. LATEST 00Z MODELS HAVE BEEN FAIRLY CONSISTENT COMPARED TO THE PAST FEW CYCLES...ALTHOUGH ONE THING OF NOTE ON BOTH THE NAM/GFS BUFKIT SOUNDINGS IS A FAIRLY SHORT TIME-FRAME WHEN THERE IS SATURATION THROUGH THE -10C TO -20C LAYER (DENDRITIC GROWTH LAYER). THIS IS RATHER PRONOUNCED ACRS THE SOUTHERN 1/2 OF THE CWA. AS IS OFTEN THE CASE IN THESE OVERRUNNING EVENTS THERE IS INITIALLY SOME DRY AIR IN THE LOW LEVELS...BUT WHAT WILL LIKELY OVERCOME THAT RATHER QUICKLY IS STRONG FRONTOGENESIS. BOTH THE NAM AND GFS SHOW VERY STRONG FORCING BY 12Z ACRS SOUTHERN VA...THEN RAPIDLY LIFT THIS OFF TO THE NORTH FROM 18Z/SUN TO 00Z/MON. THIS OFTEN AIDS THE PRECIP IN COMING IN FAST...AND THIS IS THE MAIN REASON MECKLENBURG HAS BEEN ADDED TO THE WATCH (COULD SEE ACCUMULATING ICE HERE PRIOR TO DAYBREAK SUN). HOWEVER...CONFIDENCE IN RECEIVING 0.25" OF ICE (OR GREATER) IS NOT HIGH ENOUGH TO TRANSITION TO A WARNING IN THE SOUTHERN PIEDMONT ZONES SINCE THE PRECIP MAY BECOME RATHER LIGHT BY LATE MORNING AND BEYOND AS THE -10C TO -20 C RAPIDLY DRIES OUT AND THE FORCING LIFTS NORTH. CONFIDENCE FOR 0.25" ICE IS HIGHEST ACRS THE NW ZONES AS THE DRYING IS LESS PRONOUNCED THROUGH THE AFTN HRS AND THIS IS ALSO WHERE SFC TEMPS WILL STAY THE COLDEST THE LONGEST...PERHAPS IN THE UPPER 20S IN WESTERN LOUISA/FLUVANNA THROUGH MOST OF THE DAY. THE MOST DIFFICULT REGION WITH RESPECT TO ICE ACCUMULATION WILL PROBABLY BE METRO RICHMOND...AND IT IS LIKELY THAT AN ADVISORY WILL BE NEEDED ALONG A SLIVER OF COUNTIES BORDERING THE WATCH (AS WELL AS PART OF THE WATCH THAT MAY NOT GET TRANSITIONED TO A WARNING). THESE AREAS WILL TEND TO HAVE HIGHS IN THE MID 30S...BUT WILL BE AT OR JUST BELOW 32 F THROUGH MUCH OF THE AFTN. THE MD ERN SHORE MAY SEE A FEW HRS OF SLEET/SNOW AND PERHAPS FREEZING RAIN BUT EXPECT THE MARINE LAYER TO QUICKLY CHANGE P-TYPE TO ALL RAIN NOT MUCH AFTER 18Z. EXPECT TEMPS TO BE WARM ENOUGH OVER THE VA ERN SHORE...SE VA AND NE NC FOR PCPN TO BE JUST RAIN FM THE START. HIGHS RANGE FROM AROUND 50 NE NC COAST TO AROUND 30 F IN LOUISA COUNTY. WARMER AIR (TEMPS RISING ABV FREEZING) WILL GRADUALLY WORK ITS WAY NW INTO THE PIEDMONT SUN EVENING...BUT MAY NEVER MAKE IT TO WESTERN LOUISA/FLUVANNA AND PERHAPS CUMBERLAND/GOOCHLAND. EXTENDED PORTIONS OF THE WATCH THROUGH 12Z/MON AS NEXT SHORTWAVE PUSHES INTO THE REGION FROM THE WEST BY 06Z...ENHANCING PRECIP (AND SHOULD THIS STILL BE FREEZING RAIN THERE WOULD BE ADDITIONAL ICE ACCUMULATION). LOWS SUN NGT REMAINING NEARLY STEADY AROUND 30 F NW...TO THE UPPER 40S NC COASTAL AREAS. STILL MUCH UNCERTAINTY REMAINS WITH THIS SYSTEM...SO ANY WATCH...WARNING OR ADVISORY HEADLINES FOR COUNTIES COULD CHANGE DURING THE NEXT 24 HOURS OR SO. && .LONG TERM /MONDAY THROUGH SATURDAY/... GFS/NAM DIFFER WRT FRONTAL POSITION MONDAY. NAM IS FURTHER NORTH WHERE BEST LIFT AND SUPPORT FOR PCPN WILL BE WHILE THE GFS/ECMWF IS FURTHER SOUTH WITH COPIOUS AMOUNTS OF MOISTURE ACROSS THE REGION. TSCTNS DO AGREE ON ENOUGH MOISTURE FOR CLOUDY SKIES AND AT LEAST A GOOD POTENTIAL FOR A FEW HUNDREDTHS OF QPF EVEN IN THE SOUTH. RAISED POPS TO LIKELY ALL AREAS BUT QPF-WISE THIS TIME PERIOD WILL FOCUS OVER THE NORTH. THE FRONTAL POSITION ALONG WITH ANY RESIDUAL ICE ON THE GROUND WILL MAKE FOR A WIDE RANGE IN TEMPS. KEPT HIGHS IN THE MID 40S IN COUNTIES THAT MAY HAVE SOME MORNING ICE...RANGING TO AROUND 60 F FAR SOUTHERN AREAS. ANOTHER WAVE OF LOW PRESSURE PROGGED TO ENHANCE PCPN ALONG THE FRONT AS IT MOVES SOUTH ACROSS THE FA MONDAY NIGHT. IN ADDITION... JUST ENOUGH COLD AIR IS PROGGED ACROSS NORTHERN MOST COUNTYS FOR PCPN TO BECOME MIXED WITH SOME WET SNOW LATE. CHC POPS ALL AREAS WITH LOWS FROM THE L30S NORTH TO L40S SOUTH. BOTH GFS/ECMWF CONT TO SHOW A THIRD WAVE OF LOW PRESSURE MOVING NE ALONG THE BOUNDARY CONTINUING THE PCPN CHCS ACROSS THE AREA TUE. DESPITE LOWERING THICKNESSES...TEMPS EXPECTED TO BE WARM ENOUGH FOR RAIN. HIGHS NEAR 40 NORTH TO L50S SOUTH. HIGH PRESSURE ACROSS THE NATIONS MID SECTION FINALLY PUSHES FRONTAL BOUNDARY AND ASSOCIATED MOISTURE SOUTH AND EAST OF FA TUESDAY NIGHT. WILL SHOW DECREASING CLOUDINESS. CAA RESULTS IN TEMPS DROPPING INTO THE 20S TO L30S SERN COASTAL AREAS. COLD & DRY FOR THE REST OF THE PERIOD. HIGHS WED & FRI IN THE U30S TO U40S. THURS TO BE THE COLDEST WITH HIGHS IN THE M30S-L40S. LOWS 20-30...SOME TEENS POSSIBLE IN NORMALLY COLDER SPOTS. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... COLD FRONT HAS PUSHED WELL INTO NC AND STRONG N-NE FLOW WILL GRADUALLY PUSH COLDER AIR INTO THE REGION. MOST PRECIP HAS DIMINISHED EXCEPT A LITTLE SCATTERED RAIN OVER NE NC. EXPECT A PERIOD OF VFR CONDS OVER SBY/RIC/PHF THIS AFTN AND TONIGHT...WITH MOSTLY MVFR CONDS AT ORF AND ECG AS POST FRONTAL MVFR CLOUDS LINGER OVER SE VA AND NE NC. A WAVE OF LOW PRES WILL APPROACH THE MID ATL REGION OVERNIGHT AND BEGIN A PERIOD OF RAIN AND MIXED WINTRY PRECIP EARLY SUN MORNING INTO THE AFTN AND EVENING. TEMPS FOR ECG/ORF/PHF ARE EXPECTED TO REMAIN AT OR ABOVE FREEZING SO THE PRECIP SHOULD BE MOSTLY RAIN FOR THOSE TAF SITES. HOWEVER...CANNOT NOT RULE OUT THE CHC FOR A BRIEF PERIOD OF SOME SLEET OR FREEZING RAIN FOR PHF EARLY. RIC IS EXPECTED TO SEE SOME SLEET AND FREEZING RAIN BEGIN BETWEEN 5 AM AND 7 AM SUNDAY AND THIS COULD LAST INTO THE EARLY AFTN BEFORE TEMPS RISE ABOVE FREEZING. THE WX SHOULD BEGIN 1 TO 2 HRS LATER AT SBY PSBLY BEGINNING AS MIX OF RAIN/SLEET/SNOW BEFORE CHANGING TO SLEET AND SNOW DURING THE MID MORNING. WINDS WILL CONTINUE TO BE MOSTLY NE DURING THE PERIOD WITH PSBL GUSTS TO 20-25 KTS. IFR CONDS WILL PREVAIL THRU THE MORNING AND AFTN FOR MOST AREAS. OUTLOOK... IFR CEILINGS ARE LIKELY TO PERSIST SUN NIGHT/MON WITH PERIODS OF RAIN PSBLY LAST INTO TUE AT EACH OF THE TAF SITES. CONDITIONS IMPROVE BY TUESDAY NIGHT. && .MARINE... ALL SCA HEADLINES HAVE BEEN PUT INTO EFFECT WITH THIS FORECAST PACKAGE AS CONDITIONS ARE ALREADY AT SCA THRESHOLDS OR WILL BE THERE BY LATER THIS MORNG. COLD FRNT CURRENTLY STRETCHED ALONG THE NC/VA BORDER WILL SLOWLY SLIDE SOUTH TDY...WITH A STRONG CAA SURGE FOLLOWING THE FROPA LEADING TO 20-25 KT NLY WINDS OVR THE WTRS (15-20 KT OVR THE RIVERS). WINDS SLOWLY DIMINISH TNGT AS THE FRNT PUSHES FARTHER SOUTH OF THE AREA...SO WILL DROP HEADLINES FOR THE RIVERS AT 06Z THEN THE NRN BAY AT 12Z. STILL THINK WINDS WILL STAY IN THE 15-20 KT RANGE OVR THE SRN BAY INTO SUN SO WILL END THE HEADLINE THERE AT THE END OF THE THIRD PERIOD. AS FOR SEAS OVR CSTL WTRS FOR TDY THRU SUN...EXPECT MAINLY 4-5 FT SEAS AND UP TO 6-7 FT OVR SRN CSTL WTRS. WINDS SHIFT TO THE SW AND CONDITIONS IMPROVE MON WITH SEAS AROUND 4 FT. ANOTHER COLD FRNT PUSHES THROUGH THE REGION MON NGT/TUE MORNG...WITH SCA CONDITIONS AGAIN PSBL. && .TIDES/COASTAL FLOODING... GIVEN THE ASTRONOMICAL TIMING OF THE EVENT...PREDICTED TIDES AND LEVELS ARE PROGGED TO REMAIN BLO ANY CRITICAL THRESHOLDS THROUGH THE WEEKEND. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR VAZ048-049-060>064-068-069. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR VAZ065>067. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR ANZ632-634-650- 652-654-656-658. SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR ANZ635>638. SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR ANZ630-631-633. && $$ SYNOPSIS...LKB NEAR TERM...LKB/JAB SHORT TERM...LKB/TMG LONG TERM...MPR AVIATION...JEF MARINE...MAS TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1001 AM EST SAT DEC 7 2013 .SYNOPSIS... THE FRONT WILL THEN PUSH FARTHER SOUTH TO OFF THE GEORGIA COAST LATER TODAY INTO SUNDAY MORNING...AS COLD HIGH PRESSURE BUILDS FROM THE UPPER MIDWEST TO THE EASTERN GREAT LAKES. ONE AREA OF LOW PRESSURE WILL MOVE NORTHEAST JUST WEST OF THE APPALACHIANS SUNDAY INTO MONDAY MORNING...WHILE A SECOND LOW PRESSURE AREA TRACKS NORTHEAST JUST OFF THE MID ATLANTIC COAST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT CONTINUES TO PUSH WELL SOUTH OF THE AREA. THE ONLY RAIN LEFT IS MAINLY OVER NORTHEAST NORTH CAROLINA. THIS SHOULD PUSH TO THE SOUTH OF THE AREA IN THE NEXT COUPLE OF AREAS. THIS FOLLOWS THE HRRR DEPICTION OF THE ECHOS. WITH THE CONTINUED NORTHEAST EXCEPT ACRS THE FAR NORTH...EXPECT SKIES TO REMAIN CLOUDY/MOSTLY CLOUDY AS LOW LEVEL N/NE FLOW TENDS TO KEEP IN THE LOW LEVEL MOISTURE EVEN AS BULK OF THE COLUMN DRIES OUT. LIKE THE GRIDDED LAMP TEMPS WHICH KEEP TEMPERATURES VERY STEADY THROUGH THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... N-NE SFC WINDS WILL CONTINUE TO FUNNEL COLDER AIR INTO THE MID ATLC REGION TONIGHT...SETTING THE THE STAGE FOR THE WINTER PRECIP EVENT SUN. JUST S CHC FOR LIGHT RAIN ACRS THE FAR SOUTH THIS EVENING...OTHERWISE PARTLY TO MOSTLY CLOUDY WITH LOWS IN THE MID- UPPER 20S N TO THE MID-UPPER 30S SE. HEADLINE-WISE...ONLY CHANGE HAS BEEN TO ADD MECKLENBURG COUNTY TO THE WATCH. PER COORDINATION W/ SURROUNDING OFFICES AND BASED ON LATEST THINKING...THERE REMAINS A LOT OF UNCERTAINTY IN QPF AMOUNTS AND SUBSEQUENT ICE ACCUMULATION ESPECIALLY AREAS SOUTH OF FARMVILLE. ALSO DID RAISE AN ADVSY YET AS THIS IS MAINLY STILL 3RD PERIOD. LATEST 00Z MODELS HAVE BEEN FAIRLY CONSISTENT COMPARED TO THE PAST FEW CYCLES...ALTHOUGH ONE THING OF NOTE ON BOTH THE NAM/GFS BUFKIT SOUNDINGS IS A FAIRLY SHORT TIME-FRAME WHEN THERE IS SATURATION THROUGH THE -10C TO -20C LAYER (DENDRITIC GROWTH LAYER). THIS IS RATHER PRONOUNCED ACRS THE SOUTHERN 1/2 OF THE CWA. AS IS OFTEN THE CASE IN THESE OVERRUNNING EVENTS THERE IS INITIALLY SOME DRY AIR IN THE LOW LEVELS...BUT WHAT WILL LIKELY OVERCOME THAT RATHER QUICKLY IS STRONG FRONTOGENESIS. BOTH THE NAM AND GFS SHOW VERY STRONG FORCING BY 12Z ACRS SOUTHERN VA...THEN RAPIDLY LIFT THIS OFF TO THE NORTH FROM 18Z/SUN TO 00Z/MON. THIS OFTEN AIDS THE PRECIP IN COMING IN FAST...AND THIS IS THE MAIN REASON MECKLENBURG HAS BEEN ADDED TO THE WATCH (COULD SEE ACCUMULATING ICE HERE PRIOR TO DAYBREAK SUN). HOWEVER...CONFIDENCE IN RECEIVING 0.25" OF ICE (OR GREATER) IS NOT HIGH ENOUGH TO TRANSITION TO A WARNING IN THE SOUTHERN PIEDMONT ZONES SINCE THE PRECIP MAY BECOME RATHER LIGHT BY LATE MORNING AND BEYOND AS THE -10C TO -20 C RAPIDLY DRIES OUT AND THE FORCING LIFTS NORTH. CONFIDENCE FOR 0.25" ICE IS HIGHEST ACRS THE NW ZONES AS THE DRYING IS LESS PRONOUNCED THROUGH THE AFTN HRS AND THIS IS ALSO WHERE SFC TEMPS WILL STAY THE COLDEST THE LONGEST...PERHAPS IN THE UPPER 20S IN WESTERN LOUISA/FLUVANNA THROUGH MOST OF THE DAY. THE MOST DIFFICULT REGION WITH RESPECT TO ICE ACCUMULATION WILL PROBABLY BE METRO RICHMOND...AND IT IS LIKELY THAT AN ADVISORY WILL BE NEEDED ALONG A SLIVER OF COUNTIES BORDERING THE WATCH (AS WELL AS PART OF THE WATCH THAT MAY NOT GET TRANSITIONED TO A WARNING). THESE AREAS WILL TEND TO HAVE HIGHS IN THE MID 30S...BUT WILL BE AT OR JUST BELOW 32 F THROUGH MUCH OF THE AFTN. THE MD ERN SHORE MAY SEE A FEW HRS OF SLEET/SNOW AND PERHAPS FREEZING RAIN BUT EXPECT THE MARINE LAYER TO QUICKLY CHANGE P-TYPE TO ALL RAIN NOT MUCH AFTER 18Z. EXPECT TEMPS TO BE WARM ENOUGH OVER THE VA ERN SHORE...SE VA AND NE NC FOR PCPN TO BE JUST RAIN FM THE START. HIGHS RANGE FROM AROUND 50 NE NC COAST TO AROUND 30 F IN LOUISA COUNTY. WARMER AIR (TEMPS RISING ABV FREEZING) WILL GRADUALLY WORK ITS WAY NW INTO THE PIEDMONT SUN EVENING...BUT MAY NEVER MAKE IT TO WESTERN LOUISA/FLUVANNA AND PERHAPS CUMBERLAND/GOOCHLAND. EXTENDED PORTIONS OF THE WATCH THROUGH 12Z/MON AS NEXT SHORTWAVE PUSHES INTO THE REGION FROM THE WEST BY 06Z...ENHANCING PRECIP (AND SHOULD THIS STILL BE FREEZING RAIN THERE WOULD BE ADDITIONAL ICE ACCUMULATION). LOWS SUN NGT REMAINING NEARLY STEADY AROUND 30 F NW...TO THE UPPER 40S NC COASTAL AREAS. STILL MUCH UNCERTAINTY REMAINS WITH THIS SYSTEM...SO ANY WATCH...WARNING OR ADVISORY HEADLINES FOR COUNTIES COULD CHANGE DURING THE NEXT 24 HOURS OR SO. && .LONG TERM /MONDAY THROUGH FRIDAY/... GFS/NAM DIFFER WRT FRONTAL POSITION MONDAY. NAM IS FURTHER NORTH WHERE BEST LIFT AND SUPPORT FOR PCPN WILL BE WHILE THE GFS/ECMWF IS FURTHER SOUTH WITH COPIOUS AMOUNTS OF MOISTURE ACROSS THE REGION. TSCTNS DO AGREE ON ENOUGH MOISTURE FOR CLOUDY SKIES AND AT LEAST A GOOD POTENTIAL FOR A FEW HUNDREDTHS OF QPF EVEN IN THE SOUTH. RAISED POPS TO LIKELY ALL AREAS BUT QPF-WISE THIS TIME PERIOD WILL FOCUS OVER THE NORTH. THE FRONTAL POSITION ALONG WITH ANY RESIDUAL ICE ON THE GROUND WILL MAKE FOR A WIDE RANGE IN TEMPS. KEPT HIGHS IN THE MID 40S IN COUNTIES THAT MAY HAVE SOME MORNING ICE...RANGING TO AROUND 60 F FAR SOUTHERN AREAS. ANOTHER WAVE OF LOW PRESSURE PROGGED TO ENHANCE PCPN ALONG THE FRONT AS IT MOVES SOUTH ACROSS THE FA MONDAY NIGHT. IN ADDITION... JUST ENOUGH COLD AIR IS PROGGED ACROSS NORTHERN MOST COUNTYS FOR PCPN TO BECOME MIXED WITH SOME WET SNOW LATE. CHC POPS ALL AREAS WITH LOWS FROM THE L30S NORTH TO L40S SOUTH. BOTH GFS/ECMWF CONT TO SHOW A THIRD WAVE OF LOW PRESSURE MOVING NE ALONG THE BOUNDARY CONTINUING THE PCPN CHCS ACROSS THE AREA TUE. DESPITE LOWERING THICKNESSES...TEMPS EXPECTED TO BE WARM ENOUGH FOR RAIN. HIGHS NEAR 40 NORTH TO L50S SOUTH. HIGH PRESSURE ACROSS THE NATIONS MID SECTION FINALLY PUSHES FRONTAL BOUNDARY AND ASSOCIATED MOISTURE SOUTH AND EAST OF FA TUESDAY NIGHT. WILL SHOW DECREASING CLOUDINESS. CAA RESULTS IN TEMPS DROPPING INTO THE 20S TO L30S SERN COASTAL AREAS. COLD & DRY FOR THE REST OF THE PERIOD. HIGHS WED & FRI IN THE U30S TO U40S. THURS TO BE THE COLDEST WITH HIGHS IN THE M30S-L40S. LOWS 20-30...SOME TEENS POSSIBLE IN NORMALLY COLDER SPOTS. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... A COLD FRONT IS PUSHING SOUTH INTO ERN NC ERLY THIS MORNG. WINDS BEHIND THE FRONT WILL BE GUSTY AT TIMES. PRECIP AND IFR/MVFR CIGS WILL CONTINUE THRU THE MORNG HRS. CONDITIONS SLOWLY IMPROVE FROM NORTH TO SOUTH LATER TODAY. THE NRLY WINDS WILL SLOWLY DIMINISH INTO THE AFTN. OUTLOOK...NEXT WAVE OF LOW PRESSURE WILL MOVE THROUGH ON SUNDAY WITH MORE WIDESPREAD IFR CONDITIONS AT ALL SITES. P-TYPE SHOULD BE ALL RAIN FOR KORF/KECG/KPHF...WITH A GOOD PROBABILITY FOR MIXED WINTER PRECIP AT KRIC AND KSBY BEFORE A CHANGE TO RAIN. IFR CEILINGS ARE LIKELY TO PERSIST SUN NIGHT/MON WITH PERIODS OF RAIN AT EACH OF THE TAF SITES. CONDITIONS IMPROVE TUESDAY WILL VFR/DRY WEATHER BY TUESDAY NIGHT. && .MARINE... ALL SCA HEADLINES HAVE BEEN PUT INTO EFFECT WITH THIS FORECAST PACKAGE AS CONDITIONS ARE ALREADY AT SCA THRESHOLDS OR WILL BE THERE BY LATER THIS MORNG. COLD FRNT CURRENTLY STRETCHED ALONG THE NC/VA BORDER WILL SLOWLY SLIDE SOUTH TDY...WITH A STRONG CAA SURGE FOLLOWING THE FROPA LEADING TO 20-25 KT NLY WINDS OVR THE WTRS (15-20 KT OVR THE RIVERS). WINDS SLOWLY DIMINISH TNGT AS THE FRNT PUSHES FARTHER SOUTH OF THE AREA...SO WILL DROP HEADLINES FOR THE RIVERS AT 06Z THEN THE NRN BAY AT 12Z. STILL THINK WINDS WILL STAY IN THE 15-20 KT RANGE OVR THE SRN BAY INTO SUN SO WILL END THE HEADLINE THERE AT THE END OF THE THIRD PERIOD. AS FOR SEAS OVR CSTL WTRS FOR TDY THRU SUN...EXPECT MAINLY 4-5 FT SEAS AND UP TO 6-7 FT OVR SRN CSTL WTRS. WINDS SHIFT TO THE SW AND CONDITIONS IMPROVE MON WITH SEAS AROUND 4 FT. ANOTHER COLD FRNT PUSHES THROUGH THE REGION MON NGT/TUE MORNG...WITH SCA CONDITIONS AGAIN PSBL. && .TIDES/COASTAL FLOODING... GIVEN THE ASTRONOMICAL TIMING OF THE EVENT...PREDICTED TIDES AND LEVELS ARE PROGGED TO REMAIN BLO ANY CRITICAL THRESHOLDS THROUGH THE WEEKEND. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR VAZ048-049-060>064-068-069. WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR VAZ065>067. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR ANZ632-634-650- 652-654-656-658. SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR ANZ635>638. SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR ANZ630-631-633. && $$ SYNOPSIS...LKB NEAR TERM...LKB/JAB SHORT TERM...LKB/TMG LONG TERM...MPR AVIATION...MAS/LSA MARINE...MAS TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 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 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1252 PM EST SAT DEC 7 2013 AT CMX...LAKE EFFECT SNOW WILL CONTINUE AT CMX THROUGH LATE TONIGHT. SNOWFALL ALONG WITH BLOWING SNOW WILL LIKELY CAUSE VISIBILITY TO REMAIN AT LIFR/VLIFR CONDITIONS. CEILINGS SHOULD REMAIN AT OR AROUND 1500FT THROUGH THIS TAF PERIOD. WINDS WILL REMAIN OUT OF THE WEST NORTHWEST. WITH WINDS BACKING TO THE SW LATE TONIGHT...EXPECT IMPROVMENT TO VFR CONDITIONS BY SUN MORNING. AT SAW AND IWD...SW TO W WINDS WILL FAVOR VFR CONDITIONS IN THE DRY ARCTIC AIRMASS. && .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 WARNING UNTIL 1 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. WIND CHILL ADVISORY UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR MIZ002- 004-009>011-084. 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. HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1228 PM EST SAT DEC 7 2013 .AVIATION... //DISCUSSION... VFR CONDITIONS EXPECTED THROUGH THE TAF CYCLE AS DRY ARCTIC AIRMASS DRIFTS ACROSS THE REGION. MBS/FNT HAVE A CHANCE OF MVFR CIGS FOR THE NEXT HOUR OR TWO AS CURRENT SATELLITE TRENDS SHOW THE LAKE EFFECT CLOUDS STILL HOLDING ON...BUT SCATTERING OUT. SKIES WILL CLEAR TONIGHT BUT WILL GRADUALLY FILL BACK IN ON SUNDAY AS THE NEXT SYSTEM APPROACHES. NON VFR CONDITIONS AND POTENTIAL PRECIP LOOK TO HOLD OFF TIL AFTER THIS TAF CYCLE. CURRENTLY THERE ARE A FEW GUSTS AROUND 15 KNOTS BUT VERY SPORADIC/ISOLATED AND WILL LEAVE OUT OF THE TAFS. //DTW THRESHOLD THREATS... * NONE. && .PREV DISCUSSION...ISSUED 406 AM EST SAT DEC 7 2013 SHORT TERM...TODAY AND TONIGHT LOCALIZED SURFACE RIDGING THAT HAS BEEN SUSTAINED BY LOW LEVEL COLD AIR ADVECTION WILL GIVE WAY TONIGHT TO THE CENTER OF A +1035 MB SURFACE ANTICYCLONE. STRONG SUBSIDENCE SIGNAL IN THE MODEL SOUNDINGS AS WELL AS MIDLEVEL OMEGA PLAN VIEWS SUGGESTS NO DEGREE OF DYNAMIC FORCING SUPPORTIVE FOR PRECIPITATION. WHILE MODELS ARE HAVING A DIFFICULT TIME WITH MOISTURE PROFILES AS IS ALWAYS THE CASE...SATELLITE TRENDS ON LAKE EFFECT STRATOCUMULUS SUPPORTS A BUILDING SCT-OVC CLOUD DECK EARLY THIS MORNING. THIS CLOUD DECK MAY VERY WELL ESTABLISH ITSELF PRIOR TO THE COMMENCEMENT OF DIURNAL MIXING PROCESSES. THEN THE QUESTION IS WHAT SORT OF PERSISTENCE THE SC DECK COULD HOLD DESPITE LESS THAN IMPRESSIVE MODEL SOUNDINGS AND BACKGROUND AMOUNT OF MOISTURE. THE RAP IS A NEW AND SUPPORTIVE OUTLIER SUGGESTING THAT A GOOD AMOUNT OF SATURATION/CLOUD WILL EXIST UNDER THE INVERSION BASE AT 3.5 KFT AGL. WILL TAKE THE PESSIMISTIC CLOUD ROUTE HERE FOR A MEANINGFUL CHUNK OF TODAY. THE FORECAST WILL READ MOSTLY CLOUDY TRANSITIONING TO PARTLY CLOUDY. TEMPERATURES TODAY WILL ONLY REACH THE LOWER TO MIDDLE 20S...ROUGHLY 13 TO 15 DEGREES BELOW AVERAGE. THE FORECAST QUESTION FOR TONIGHT IS WHAT LOWS WILL DROP TO. IT APPEARS THE STAGE WILL BE SET FOR FAVORABLE RADIATIVE COOLING WITH THE ONLY MISSING CONDITION...A FRESH SNOWPACK. DON`T HAVE A GOOD CALIBRATED FEEL YET. SIDED WITH A MIX OF MOS...WHICH GIVES LOW TEENS OUTSIDE OF THE HEAT ISLAND...WITH MID TEENS IN DETROIT METRO. LONG TERM...SUNDAY THROUGH FRIDAY HIGH AMPLITUDE MID LEVEL TROUGHING CURRENTLY CENTERED FROM NORTH CENTRAL CANADA INTO THE MID SECTION OF THE COUNTRY WILL REMAIN THE PREDOMINANT LARGE SCALE FEATURE WELL INTO NEXT WEEK AS THE MAIN HEIGHT FALL CENTER SLOWLY SHIFTS EASTWARD WITH TIME. THIS WILL PRESENT A SUSTAINABLE CONDUIT FOR MULTIPLE REINFORCING ROUNDS OF ARCTIC AIR TO INFILTRATE SE MICHIGAN RIGHT THROUGH THE UPCOMING WORK WEEK. LEAD PUSH OF MODIFIED ARCTIC FIRMLY IN RESIDENCE LOCALLY TO START SUNDAY LODGED WITHIN A 1035MB LOW LEVEL ANTICYCLONE SLOWLY SHIFTING THROUGH THE REGION. SUPPRESSED MIXING POTENTIAL WITHIN A STABLE LOW LEVEL EASTERLY FLOW WILL ENSURE HIGHS AGAIN HOLD IN THE 20S. ATTENTION FOR THE SUNDAY NIGHT PERIOD REMAINS CENTERED ON THE DOWNSTREAM EVOLUTION OF THE LEAD SHORTWAVE CURRENTLY ANCHORING THE BASE OF THE MEAN TROUGH. STRONG HEIGHT FALLS BARRELING SOUTHWARD OUT OF CENTRAL CANADA THIS WEEKEND WILL SQUEEZE THIS WAVE NORTHEASTWARD...THE VORTICITY CENTER SHEARING FROM NORTHERN IL/ SOUTHERN WI THROUGH NORTHERN LOWER MI BY SUNDAY NIGHT. ASSESSMENT OF LATEST 300-200MB POTENTIAL VORTICITY FIELDS SUGGEST ENOUGH SEPARATION WILL EXIST BETWEEN THESE HEIGHT FALL CORES TO LEAVE THE LEAD WAVE IN A MORE WEAKENED/LESS PHASED STATE AS THE ATTENDANT SURFACE WAVE SHIFTS THROUGH THE LOWER PENINSULA. WHILE THE BETTER MOISTURE ADVECTION WITHIN THE PREVAILING SOUTHWESTERLIES WILL GET PINCHED OFF TO THE SOUTH/EAST...SOLID DEPTH AND MAGNITUDE TO THE INBOUND MOIST LAYER (2-4 G/KG OF SPECIFIC HUMIDITY WITHIN THE 850-925 MB LAYER) WILL EXIST AT THE INTERFACE OF THE NORTHWARD ARCING ELEVATED WARM FRONTAL BOUNDARY. THERE MAY ALSO BE SOME LAKE MOISTURE CONTRIBUTION GIVEN EASTERLY BOUNDARY LAYER FLOW. GIVEN THE PROJECTED TRAJECTORY OF THIS SYSTEM...STRONGEST FORCING DOES REMAIN CENTERED TO THE NORTHWEST...ALTHOUGH THE TRI-CITIES WILL BE ON THE FRINGE ON THE MAIN AREA OF DCVA AND BETTER CONVERGENCE. WITH THAT SAID...CERTAINLY ENOUGH BACKGROUND ASCENT WORKING INTO A SUFFICIENTLY MOIST ENVIRONMENT TO BRING A WIDESPREAD AREA OF LIGHT SNOW THROUGH SOUTHEAST MICHIGAN SUNDAY NIGHT. THE COMBINATION OF THE ADDED DEGREE OF FORCING AND LIKELIHOOD OF SLIGHTLY LONGER RESIDENCE TIME WILL FOCUS THE GREATER ACCUMULATION POTENTIAL INTO THE TRI-CITIES...WHERE SOME AMOUNTS IN EXCESS OF AN INCH STILL SEEM PLAUSIBLE. ELSEWHERE AN INCH OR LESS WITH SOME REDUCTION IN SNOW RATIOS EXPECTED WITH THE LOW LEVEL PROFILE WARMING WITH TIME. COLD AIR ADVECTION QUICKLY ENSUES ON THE HEELS OF THIS SYSTEM THROUGHOUT MONDAY. SHORT LIVED DRY SLOT FOR THE MORNING PERIOD BEFORE A LAKE ENHANCED MOISTURE PLUME EXPANDS EASTWARD WITHIN THE BACKGROUND OF COLD/CYCLONIC FLOW. THIS WILL SUPPORT AN EXTENSIVE STRATUS DECK FOR MUCH OF THE DAY...AND ALLOW FOR SOME LIGHT SNOW SHOWER/FLURRY PRODUCTION. THE MAIN ARCTIC BLAST WILL ACCOMPANY A CLIPPER CRUISING THROUGH THE NORTHERN GREAT LAKES ON TUESDAY. A TRAILING WAVE MAY REINFORCE THIS AIRMASS INTO WEDNESDAY...THE NET RESULT BEING A STRETCH OF TEMPERATURES A GOOD 15 TO 20 DEGREES BELOW NORMAL FOR THE 2ND WEEK IN DECEMBER. A SOLID GRADIENT ATTENDANT TO THESE NORTHERN STREAM WAVES WILL PROVIDE THE ADDITIVE WIND ELEMENT...RESULTING IN DAYTIME WIND CHILL READINGS OF SINGLE DIGITS TUESDAY AND WEDNESDAY. MARINE... A STRONGER WESTERLY WIND WILL REMAIN IN PLACE TODAY ACROSS NORTHERN LAKE HURON AS ARCTIC AIR CONTINUES TO FUNNEL ACROSS THE WATERS. WINDS WILL DECREASE TONIGHT AND SUNDAY AS STRONG HIGH PRESSURE MOVES THROUGH THE REGION. SOUTHEAST WINDS WILL STRENGTHEN AGAIN SUNDAY NIGHT AS LOW PRESSURE TRACKS THROUGH LOWER MICHIGAN. WINDS WILL SHIFT TO SOUTHWESTERLY IN THE WAKE OF THIS SYSTEM ON MONDAY. INCREASING INSTABILITY AS ARCTIC AIR SPILLS BACK INTO THE REGION WILL INTRODUCE THE POSSIBILITY FOR GALES MONDAY INTO MONDAY NIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....DRK SHORT TERM...CB LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
631 AM EST SAT DEC 7 2013 .AVIATION... //DISCUSSION... UNSTABLE REGIME OVER THE GREAT LAKES HAS BEEN ALLOWING FOR STRATOCUMULUS PERSISTENCE OVER THE GREAT LAKES WITH MANY LOCATIONS THIS MORNING UNDER A HEALTHY STRATOCU DECK. LATEST RAP MOISTURE PROFILES SUPPORTS TRAPPING SATURATION AND MOISTURE UNDER ACTIVE 850-500MB SUBSIDENCE. WITH A BUILDING SURFACE ANTICYCLONE AND A LOW BACKGROUND RH SIGNAL...SUSPECT CLOUDS WILL LESSEN SIGNIFICANTLY BY THE AFTERNOON HOURS. CONDITIONS TONIGHT WILL REMAIN BENIGN AHEAD OF INCREASING MIDLEVEL MOISTURE TOMORROW. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN DURATION OF CEILINGS BELOW 5000 FEET TODAY. && .PREV DISCUSSION...ISSUED 406 AM EST SAT DEC 7 2013 SHORT TERM...TODAY AND TONIGHT LOCALIZED SURFACE RIDGING THAT HAS BEEN SUSTAINED BY LOW LEVEL COLD AIR ADVECTION WILL GIVE WAY TONIGHT TO THE CENTER OF A +1035 MB SURFACE ANTICYCLONE. STRONG SUBSIDENCE SIGNAL IN THE MODEL SOUNDINGS AS WELL AS MIDLEVEL OMEGA PLAN VIEWS SUGGESTS NO DEGREE OF DYNAMIC FORCING SUPPORTIVE FOR PRECIPITATION. WHILE MODELS ARE HAVING A DIFFICULT TIME WITH MOISTURE PROFILES AS IS ALWAYS THE CASE...SATELLITE TRENDS ON LAKE EFFECT STRATOCUMULUS SUPPORTS A BUILDING SCT-OVC CLOUD DECK EARLY THIS MORNING. THIS CLOUD DECK MAY VERY WELL ESTABLISH ITSELF PRIOR TO THE COMMENCEMENT OF DIURNAL MIXING PROCESSES. THEN THE QUESTION IS WHAT SORT OF PERSISTENCE THE SC DECK COULD HOLD DESPITE LESS THAN IMPRESSIVE MODEL SOUNDINGS AND BACKGROUND AMOUNT OF MOISTURE. THE RAP IS A NEW AND SUPPORTIVE OUTLIER SUGGESTING THAT A GOOD AMOUNT OF SATURATION/CLOUD WILL EXIST UNDER THE INVERSION BASE AT 3.5 KFT AGL. WILL TAKE THE PESSIMISTIC CLOUD ROUTE HERE FOR A MEANINGFUL CHUNK OF TODAY. THE FORECAST WILL READ MOSTLY CLOUDY TRANSITIONING TO PARTLY CLOUDY. TEMPERATURES TODAY WILL ONLY REACH THE LOWER TO MIDDLE 20S...ROUGHLY 13 TO 15 DEGREES BELOW AVERAGE. THE FORECAST QUESTION FOR TONIGHT IS WHAT LOWS WILL DROP TO. IT APPEARS THE STAGE WILL BE SET FOR FAVORABLE RADIATIVE COOLING WITH THE ONLY MISSING CONDITION...A FRESH SNOWPACK. DON`T HAVE A GOOD CALIBRATED FEEL YET. SIDED WITH A MIX OF MOS...WHICH GIVES LOW TEENS OUTSIDE OF THE HEAT ISLAND...WITH MID TEENS IN DETROIT METRO. LONG TERM...SUNDAY THROUGH FRIDAY HIGH AMPLITUDE MID LEVEL TROUGHING CURRENTLY CENTERED FROM NORTH CENTRAL CANADA INTO THE MID SECTION OF THE COUNTRY WILL REMAIN THE PREDOMINANT LARGE SCALE FEATURE WELL INTO NEXT WEEK AS THE MAIN HEIGHT FALL CENTER SLOWLY SHIFTS EASTWARD WITH TIME. THIS WILL PRESENT A SUSTAINABLE CONDUIT FOR MULTIPLE REINFORCING ROUNDS OF ARCTIC AIR TO INFILTRATE SE MICHIGAN RIGHT THROUGH THE UPCOMING WORK WEEK. LEAD PUSH OF MODIFIED ARCTIC FIRMLY IN RESIDENCE LOCALLY TO START SUNDAY LODGED WITHIN A 1035MB LOW LEVEL ANTICYCLONE SLOWLY SHIFTING THROUGH THE REGION. SUPPRESSED MIXING POTENTIAL WITHIN A STABLE LOW LEVEL EASTERLY FLOW WILL ENSURE HIGHS AGAIN HOLD IN THE 20S. ATTENTION FOR THE SUNDAY NIGHT PERIOD REMAINS CENTERED ON THE DOWNSTREAM EVOLUTION OF THE LEAD SHORTWAVE CURRENTLY ANCHORING THE BASE OF THE MEAN TROUGH. STRONG HEIGHT FALLS BARRELING SOUTHWARD OUT OF CENTRAL CANADA THIS WEEKEND WILL SQUEEZE THIS WAVE NORTHEASTWARD...THE VORTICITY CENTER SHEARING FROM NORTHERN IL/ SOUTHERN WI THROUGH NORTHERN LOWER MI BY SUNDAY NIGHT. ASSESSMENT OF LATEST 300-200MB POTENTIAL VORTICITY FIELDS SUGGEST ENOUGH SEPARATION WILL EXIST BETWEEN THESE HEIGHT FALL CORES TO LEAVE THE LEAD WAVE IN A MORE WEAKENED/LESS PHASED STATE AS THE ATTENDANT SURFACE WAVE SHIFTS THROUGH THE LOWER PENINSULA. WHILE THE BETTER MOISTURE ADVECTION WITHIN THE PREVAILING SOUTHWESTERLIES WILL GET PINCHED OFF TO THE SOUTH/EAST...SOLID DEPTH AND MAGNITUDE TO THE INBOUND MOIST LAYER (2-4 G/KG OF SPECIFIC HUMIDITY WITHIN THE 850-925 MB LAYER) WILL EXIST AT THE INTERFACE OF THE NORTHWARD ARCING ELEVATED WARM FRONTAL BOUNDARY. THERE MAY ALSO BE SOME LAKE MOISTURE CONTRIBUTION GIVEN EASTERLY BOUNDARY LAYER FLOW. GIVEN THE PROJECTED TRAJECTORY OF THIS SYSTEM...STRONGEST FORCING DOES REMAIN CENTERED TO THE NORTHWEST...ALTHOUGH THE TRI-CITIES WILL BE ON THE FRINGE ON THE MAIN AREA OF DCVA AND BETTER CONVERGENCE. WITH THAT SAID...CERTAINLY ENOUGH BACKGROUND ASCENT WORKING INTO A SUFFICIENTLY MOIST ENVIRONMENT TO BRING A WIDESPREAD AREA OF LIGHT SNOW THROUGH SOUTHEAST MICHIGAN SUNDAY NIGHT. THE COMBINATION OF THE ADDED DEGREE OF FORCING AND LIKELIHOOD OF SLIGHTLY LONGER RESIDENCE TIME WILL FOCUS THE GREATER ACCUMULATION POTENTIAL INTO THE TRI-CITIES...WHERE SOME AMOUNTS IN EXCESS OF AN INCH STILL SEEM PLAUSIBLE. ELSEWHERE AN INCH OR LESS WITH SOME REDUCTION IN SNOW RATIOS EXPECTED WITH THE LOW LEVEL PROFILE WARMING WITH TIME. COLD AIR ADVECTION QUICKLY ENSUES ON THE HEELS OF THIS SYSTEM THROUGHOUT MONDAY. SHORT LIVED DRY SLOT FOR THE MORNING PERIOD BEFORE A LAKE ENHANCED MOISTURE PLUME EXPANDS EASTWARD WITHIN THE BACKGROUND OF COLD/CYCLONIC FLOW. THIS WILL SUPPORT AN EXTENSIVE STRATUS DECK FOR MUCH OF THE DAY...AND ALLOW FOR SOME LIGHT SNOW SHOWER/FLURRY PRODUCTION. THE MAIN ARCTIC BLAST WILL ACCOMPANY A CLIPPER CRUISING THROUGH THE NORTHERN GREAT LAKES ON TUESDAY. A TRAILING WAVE MAY REINFORCE THIS AIRMASS INTO WEDNESDAY...THE NET RESULT BEING A STRETCH OF TEMPERATURES A GOOD 15 TO 20 DEGREES BELOW NORMAL FOR THE 2ND WEEK IN DECEMBER. A SOLID GRADIENT ATTENDANT TO THESE NORTHERN STREAM WAVES WILL PROVIDE THE ADDITIVE WIND ELEMENT...RESULTING IN DAYTIME WIND CHILL READINGS OF SINGLE DIGITS TUESDAY AND WEDNESDAY. MARINE... A STRONGER WESTERLY WIND WILL REMAIN IN PLACE TODAY ACROSS NORTHERN LAKE HURON AS ARCTIC AIR CONTINUES TO FUNNEL ACROSS THE WATERS. WINDS WILL DECREASE TONIGHT AND SUNDAY AS STRONG HIGH PRESSURE MOVES THROUGH THE REGION. SOUTHEAST WINDS WILL STRENGTHEN AGAIN SUNDAY NIGHT AS LOW PRESSURE TRACKS THROUGH LOWER MICHIGAN. WINDS WILL SHIFT TO SOUTHWESTERLY IN THE WAKE OF THIS SYSTEM ON MONDAY. INCREASING INSTABILITY AS ARCTIC AIR SPILLS BACK INTO THE REGION WILL INTRODUCE THE POSSIBILITY FOR GALES MONDAY INTO MONDAY NIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....CB SHORT TERM...CB LONG TERM....MR MARINE.......MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
406 AM EST SAT DEC 7 2013 .SHORT TERM...TODAY AND TONIGHT LOCALIZED SURFACE RIDGING THAT HAS BEEN SUSTAINED BY LOW LEVEL COLD AIR ADVECTION WILL GIVE WAY TONIGHT TO THE CENTER OF A +1035 MB SURFACE ANTICYCLONE. STRONG SUBSIDENCE SIGNAL IN THE MODEL SOUNDINGS AS WELL AS MIDLEVEL OMEGA PLAN VIEWS SUGGESTS NO DEGREE OF DYNAMIC FORCING SUPPORTIVE FOR PRECIPITATION. WHILE MODELS ARE HAVING A DIFFICULT TIME WITH MOISTURE PROFILES AS IS ALWAYS THE CASE...SATELLITE TRENDS ON LAKE EFFECT STRATOCUMULUS SUPPORTS A BUILDING SCT-OVC CLOUD DECK EARLY THIS MORNING. THIS CLOUD DECK MAY VERY WELL ESTABLISH ITSELF PRIOR TO THE COMMENCEMENT OF DIURNAL MIXING PROCESSES. THEN THE QUESTION IS WHAT SORT OF PERSISTENCE THE SC DECK COULD HOLD DESPITE LESS THAN IMPRESSIVE MODEL SOUNDINGS AND BACKGROUND AMOUNT OF MOISTURE. THE RAP IS A NEW AND SUPPORTIVE OUTLIER SUGGESTING THAT A GOOD AMOUNT OF SATURATION/CLOUD WILL EXIST UNDER THE INVERSION BASE AT 3.5 KFT AGL. WILL TAKE THE PESSIMISTIC CLOUD ROUTE HERE FOR A MEANINGFUL CHUNK OF TODAY. THE FORECAST WILL READ MOSTLY CLOUDY TRANSITIONING TO PARTLY CLOUDY. TEMPERATURES TODAY WILL ONLY REACH THE LOWER TO MIDDLE 20S...ROUGHLY 13 TO 15 DEGREES BELOW AVERAGE. THE FORECAST QUESTION FOR TONIGHT IS WHAT LOWS WILL DROP TO. IT APPEARS THE STAGE WILL BE SET FOR FAVORABLE RADIATIVE COOLING WITH THE ONLY MISSING CONDITION...A FRESH SNOWPACK. DON`T HAVE A GOOD CALIBRATED FEEL YET. SIDED WITH A MIX OF MOS...WHICH GIVES LOW TEENS OUTSIDE OF THE HEAT ISLAND...WITH MID TEENS IN DETROIT METRO. && .LONG TERM...SUNDAY THROUGH FRIDAY HIGH AMPLITUDE MID LEVEL TROUGHING CURRENTLY CENTERED FROM NORTH CENTRAL CANADA INTO THE MID SECTION OF THE COUNTRY WILL REMAIN THE PREDOMINANT LARGE SCALE FEATURE WELL INTO NEXT WEEK AS THE MAIN HEIGHT FALL CENTER SLOWLY SHIFTS EASTWARD WITH TIME. THIS WILL PRESENT A SUSTAINABLE CONDUIT FOR MULTIPLE REINFORCING ROUNDS OF ARCTIC AIR TO INFILTRATE SE MICHIGAN RIGHT THROUGH THE UPCOMING WORK WEEK. LEAD PUSH OF MODIFIED ARCTIC FIRMLY IN RESIDENCE LOCALLY TO START SUNDAY LODGED WITHIN A 1035MB LOW LEVEL ANTICYCLONE SLOWLY SHIFTING THROUGH THE REGION. SUPPRESSED MIXING POTENTIAL WITHIN A STABLE LOW LEVEL EASTERLY FLOW WILL ENSURE HIGHS AGAIN HOLD IN THE 20S. ATTENTION FOR THE SUNDAY NIGHT PERIOD REMAINS CENTERED ON THE DOWNSTREAM EVOLUTION OF THE LEAD SHORTWAVE CURRENTLY ANCHORING THE BASE OF THE MEAN TROUGH. STRONG HEIGHT FALLS BARRELING SOUTHWARD OUT OF CENTRAL CANADA THIS WEEKEND WILL SQUEEZE THIS WAVE NORTHEASTWARD...THE VORTICITY CENTER SHEARING FROM NORTHERN IL/ SOUTHERN WI THROUGH NORTHERN LOWER MI BY SUNDAY NIGHT. ASSESSMENT OF LATEST 300-200MB POTENTIAL VORTICITY FIELDS SUGGEST ENOUGH SEPARATION WILL EXIST BETWEEN THESE HEIGHT FALL CORES TO LEAVE THE LEAD WAVE IN A MORE WEAKENED/LESS PHASED STATE AS THE ATTENDANT SURFACE WAVE SHIFTS THROUGH THE LOWER PENINSULA. WHILE THE BETTER MOISTURE ADVECTION WITHIN THE PREVAILING SOUTHWESTERLIES WILL GET PINCHED OFF TO THE SOUTH/EAST...SOLID DEPTH AND MAGNITUDE TO THE INBOUND MOIST LAYER (2-4 G/KG OF SPECIFIC HUMIDITY WITHIN THE 850-925 MB LAYER) WILL EXIST AT THE INTERFACE OF THE NORTHWARD ARCING ELEVATED WARM FRONTAL BOUNDARY. THERE MAY ALSO BE SOME LAKE MOISTURE CONTRIBUTION GIVEN EASTERLY BOUNDARY LAYER FLOW. GIVEN THE PROJECTED TRAJECTORY OF THIS SYSTEM...STRONGEST FORCING DOES REMAIN CENTERED TO THE NORTHWEST...ALTHOUGH THE TRI-CITIES WILL BE ON THE FRINGE ON THE MAIN AREA OF DCVA AND BETTER CONVERGENCE. WITH THAT SAID...CERTAINLY ENOUGH BACKGROUND ASCENT WORKING INTO A SUFFICIENTLY MOIST ENVIRONMENT TO BRING A WIDESPREAD AREA OF LIGHT SNOW THROUGH SOUTHEAST MICHIGAN SUNDAY NIGHT. THE COMBINATION OF THE ADDED DEGREE OF FORCING AND LIKELIHOOD OF SLIGHTLY LONGER RESIDENCE TIME WILL FOCUS THE GREATER ACCUMULATION POTENTIAL INTO THE TRI-CITIES...WHERE SOME AMOUNTS IN EXCESS OF AN INCH STILL SEEM PLAUSIBLE. ELSEWHERE AN INCH OR LESS WITH SOME REDUCTION IN SNOW RATIOS EXPECTED WITH THE LOW LEVEL PROFILE WARMING WITH TIME. COLD AIR ADVECTION QUICKLY ENSUES ON THE HEELS OF THIS SYSTEM THROUGHOUT MONDAY. SHORT LIVED DRY SLOT FOR THE MORNING PERIOD BEFORE A LAKE ENHANCED MOISTURE PLUME EXPANDS EASTWARD WITHIN THE BACKGROUND OF COLD/CYCLONIC FLOW. THIS WILL SUPPORT AN EXTENSIVE STRATUS DECK FOR MUCH OF THE DAY...AND ALLOW FOR SOME LIGHT SNOW SHOWER/FLURRY PRODUCTION. THE MAIN ARCTIC BLAST WILL ACCOMPANY A CLIPPER CRUISING THROUGH THE NORTHERN GREAT LAKES ON TUESDAY. A TRAILING WAVE MAY REINFORCE THIS AIRMASS INTO WEDNESDAY...THE NET RESULT BEING A STRETCH OF TEMPERATURES A GOOD 15 TO 20 DEGREES BELOW NORMAL FOR THE 2ND WEEK IN DECEMBER. A SOLID GRADIENT ATTENDANT TO THESE NORTHERN STREAM WAVES WILL PROVIDE THE ADDITIVE WIND ELEMENT...RESULTING IN DAYTIME WIND CHILL READINGS OF SINGLE DIGITS TUESDAY AND WEDNESDAY. && .MARINE... A STRONGER WESTERLY WIND WILL REMAIN IN PLACE TODAY ACROSS NORTHERN LAKE HURON AS ARCTIC AIR CONTINUES TO FUNNEL ACROSS THE WATERS. WINDS WILL DECREASE TONIGHT AND SUNDAY AS STRONG HIGH PRESSURE MOVES THROUGH THE REGION. SOUTHEAST WINDS WILL STRENGTHEN AGAIN SUNDAY NIGHT AS LOW PRESSURE TRACKS THROUGH LOWER MICHIGAN. WINDS WILL SHIFT TO SOUTHWESTERLY IN THE WAKE OF THIS SYSTEM ON MONDAY. INCREASING INSTABILITY AS ARCTIC AIR SPILLS BACK INTO THE REGION WILL INTRODUCE THE POSSIBILITY FOR GALES MONDAY INTO MONDAY NIGHT. && .AVIATION...ISSUED 1155 PM EST FRI DEC 6 2013 //DISCUSSION... LAKE MOISTURE CONTINUES TO BRING IN STRATUS BETWEEN 2500 AND 3500 FEET TONIGHT WITH A WESTERLY FEED AT THE LOW LEVELS. THIS LAKE MOISTURE HAS BEEN AFFECTING THE TAF SITES ON AN ON DURING THE EVENING...MAINLY FNT AND MBS...BUT STILL MAKING IT ALL THE WAY TO PTK AND DET. OVERALL THINKING IS MBS BEING CLOSER TO THE MOISTURE SOURCE WILL BE MOST AT RISK...WITH LOWER CHANCES AT THE METRO AIRPORTS. HIGH PRESSURE BUILDING IN ON SATURDAY WILL CLEAR OUT THIS LAKE MOISTURE...LEAVING MOSTLY CLEAR SKIES FOR MUCH OF THE DAY. FOR DTW...THINKING IS THAT THE AFOREMENTIONED LAKE MOISTURE WILL ONLY BRING A FEW-SCT DECK AROUND 3K FT. HOWEVER THERE IS A SMALL CHANCE FOR A BKN DECK AT THIS LEVEL FOR A PERIOD OF TIME OVERNIGHT AND EARLY SATURDAY MORNING. AT THIS TIME CONFIDENCE IN A BKN DECK FOR A LONG PERIOD OF TIME IS LOW ENOUGH TO LEAVE OUT OF THE TAFS. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILINGS BELOW 5000 FEET OVERNIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CB LONG TERM....MR MARINE.......MR AVIATION.....KURIMSKI YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
734 PM CST SUN DEC 8 2013 .SYNOPSIS... ISSUED AT 326 PM CST SUN DEC 8 2013 H5 ANALYSIS FROM THIS MORNING HAS A HIGHLY AMPLIFIED PATTERN ACROSS NOAM THIS MORNING WITH A RIDGE EXTENDING INTO THE GULF OF ALASKA. A CLOSED LOW WAS OVER WESTERN PORTIONS OF THE HUDSON BAY WITH A DEEP TROUGH OF LOW PRESSURE EXTENDING SSWD INTO THE ROCKIES AND SWRN US. NUMEROUS EMBEDDED SHORTWAVES WERE NOTED ACROSS THE WESTERN CONUS THIS MORNING. THE FIRST OVER SWRN WYOMING...WHICH IS CROSSING CENTRAL COLORADO AND IS EMERGING ONTO THE FRONT RANGES JUST SOUTH OF DENVER...PER SATELLITE AND RADAR IMAGERY. ANOTHER SHORTWAVE WAS LOCATED OVER SWRN SASKATCHEWAN AND SRN ALBERTA...AND A THIRD WAS NOTED OFF THE NRN CALIFORNIA COAST. AT THE SURFACE...AN AREA OF SNOW IN ASSOCIATION WITH THE FIRST SHORTWAVE...EXTENDED FROM AROUND LIMON COLORADO...NEWD TO FAR SOUTHWESTERN NEBRASKA. THE HEAVIEST SNOW PER RADAR IMAGERY EXTENDED FROM NEAR LIMON COLORADO TO NEAR IMPERIAL. THIS ACTIVITY HAS BEEN MOVING TO THE EAST NORTHEAST AND IS EXPECTED TO REMAIN MAINLY SOUTH OF THE FORECAST AREA THIS AFTERNOON. THE EXCEPTION IS ACROSS THE FAR SOUTHWESTERN COUNTIES WHERE 1 TO 2 INCHES IS POSSIBLE THIS AFTERNOON. ELSEWHERE...ANY ACCUMULATIONS ARE EXPECTED TO BE AN INCH OR LESS. AS OF 3 PM CST...UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES RANGED FROM 11 AT VALENTINE TO 17 AT OGALLALA. && .UPDATE... ISSUED AT 729 PM CST SUN DEC 8 2013 THE RAP AND HRRR TEMPERATURE AND WIND CHILL FORECASTS APPEAR TO BE ON TRACK WITH KVTN SHOWING A WIND CHILL OF -26F AT 7 PM CST. THERE ARE SOME MID CLOUDS MOVING IN FROM WY WHICH WILL LIMIT THE AMOUNT OF TIME FOR RADIATIONAL COOLING. THUS CONDITIONS ARE NOT FAVORABLE FOR ROCK BOTTOM LOWS BUT -10F TO -20F SHOULD DEVELOP ALONG AND WEST OF HIGHWAY 83 TONIGHT. TEMPS HAVE BEEN LOWERED IN THE NORTH AND A WIND CHILL WARNING IS IN PLACE FROM VALENTINE WEST TO GORDON. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 326 PM CST SUN DEC 8 2013 SHORT WAVE MOVING ACROSS THE NEB/KS BORDER...WHICH MODELS HAVE HANDLED FAIRLY WELL. LIGHT SNOW WILL BE TAPERING TO FLURRIES ACROSS PORTIONS OF SOUTHWEST AND CENTRAL NEBRASKA BEFORE ENDING LATER THIS EVENING. ADDITIONAL SNOWFALL COULD REACH UP TO THREE QUARTERS OF AN INCH...HOWEVER MOST AREAS IN THE SE CWA TO SEE A COUPLE OF TENTHS. CLEARING SKIES ARE ALREADY SEEN ON VISIBLE SAT ACROSS THE PANHANDLE AND NW NEB. HIGH PRESSURE WILL BEGIN TO NOSE DOWN INTO THE AREA TONIGHT...WHICH WILL COMBINE WITH THE SNOW PACK TO ALLOW FOR GOOD RADIATIONAL COOLING. RECENT LOWS HAVE BEEN BELOW GUIDANCE WHEN SKIES HAVE CLEARED...SO TOOK COOLER MAV GUIDANCE AND DROPPED A COUPLE OF DEGREES...WHICH MAYBE CONSERVATIVE FOR PORTIONS OF THE NW CWA...WHERE MORE THAN HALF A FOOT OF SNOW REMAINS ON THE GROUND. THIS PLACES LOWS IN THE -5 TO -15 DEGREE RANGE. NORTHWEST WINDS MOVING IN WITH THE CLEARING...ALTHOUGH THEY WILL BE DIMINISHING. THE COMBINATION OF LIGHT WINDS AND BITTER COLD TEMPS WILL ALLOW FOR WIND CHILLS TO FALL INTO THE -20 TO -30 RANGE...LOCALLY LOWER ACROSS NW ZONES. WILL GO WITH A WIND CHILL ADVISORY FOR ENTIRE CWA. TOMORROW MODELS HOLD 850 MB TEMPS FAIRLY STEADY...AND WITH MOSTLY SUNNY SKIES EXPECT HIGHS TO REBOUND A LITTLE WARMER THAN TODAY...HIGHS SHOULD REBOUND INTO THE TEENS TO NEAR 20. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 326 PM CST SUN DEC 8 2013 MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING CHALLENGES ARE TEMPERATURES...THEN LOW PRECIPITATION CHANCES FOR TUESDAY NIGHT. ON MONDAY NIGHT...A SURFACE TROUGH OF LOW PRESSURE WILL TRACK FROM THE CENTRAL PLAINS EAST INTO THE UPPER MIDWEST. LIMITED CAA WILL ACCOMPANY PASSAGE OF THE TROUGH. HOWEVER...IT WILL HELP TO KEEP THE LOW LEVEL WINDS MIXED ON MONDAY NIGHT...THUS MILDER TEMPERATURES ARE EXPECTED. ALBEIT...LOWS WILL STILL BE COLD WITH READINGS IN THE SINGLE DIGITS. ON TUESDAY...WESTERLY DOWNSLOPE WINDS WILL CONTINUE INCREASE SOMEWHAT TO 10 TO 15 MPH. DECIDED TO UNDERCUT GUIDANCE FOR HIGHS TUESDAY...BASED ON SNOW COVER AND LIMITED MIXING POTENTIAL. THIS LED TO HIGHS MAINLY IN THE 20S...WITH SOME TEMPS NEAR THE FREEZING MARK ACROSS THE FAR SOUTHWEST. ON TUESDAY NIGHT...AN ARCTIC COLD FRONT WILL BACK INTO NORTHERN AND NORTHEASTERN NEBRASKA WITH A NICE PV MAX ARRIVING OVERNIGHT. CROSS SECTIONS ACROSS NORTHERN NEBRASKA ARE INDICATIVE OF SOME WEAK LIFT IN THE DENDRITIC LAYER WHICH MAXES OUT AROUND 06Z WEDNESDAY. TOP DOWN SATURATION WILL HAVE TO OCCUR WITH ANY PCPN WHICH MAY FALL...SO WILL LIMIT POP MENTION TO SLIGHTS FOR NOW...AND KEEP POPS ACROSS THE NRN CWA AS CROSS SECTIONS NEVER MOISTEN UP ACROSS THE SRN CWA. ON WEDNESDAY SURFACE HIGH PRESSURE WILL BUILD INTO THE MID MISSOURI VALLEY. WINDS WILL SHIFT TO THE SOUTHWEST DURING THE AFTERNOON HOURS...AND WILL RECYCLE COLD AIR ACROSS THE FORECAST AREA. HIGHS WILL BE COLD...RANGING FROM THE MIDDLE TEENS IN THE NORTHEAST...TO THE UPPER 20S IN THE FAR SOUTHWEST. WEDNESDAY NIGHT THROUGH SUNDAY...THE MID RANGE MODEL SOLUTIONS CONTINUE TO INDICATE LOW AMPLITUDE WEST NORTHWESTERLY FLOW ACROSS THE CONUS FOR THE END OF THE WEEK INTO EARLY NEXT WEEK. BOTH THE ECMWF AND GFS SOLNS ARE TRENDING TOWARD THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EMBEDDED IN THE SRN STREAM TOWARD FRIDAY. BOTH SOLNS LIFT THIS ENERGY SOUTH OF THE AREA...SO A DRY FORECAST CONTINUES. AFTER TEMPERATURES TREND HIGHER FOR THURSDAY AND FRIDAY WITH HIGHS IN THE 30S...COOLER TEMPERATURES WILL ARRIVE ON FRIDAY NIGHT AS AN ARCTIC COLD FRONT BACKS INTO THE FORECAST AREA. HIGHS WILL BE COOLER IN THE 20S AND LOWER 30S SATURDAY...FOLLOWED BY 30S AND LOWER 40S FOR SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 527 PM CST SUN DEC 8 2013 VFR IS EXPECTED ALL AREAS TONIGHT AND MONDAY. A BATCH OF MID LEVEL CLOUDS...CURRENTLY OVER NORTHEAST WY...WILL MOVE OVERHEAD TONIGHT FOLLOWED BY SOME CLEARING MONDAY MORNING AND SCATTERED HIGH CLOUDS THEREAFTER. NO FOG WAS INDICATED IN THE NAM OR HRRR MODELS TONIGHT. INDICATIONS ARE THE REINFORCING ARCTIC FRONT MOVING THROUGH THE FCST AREA WILL SCOUR ALL MOISTURE FROM AREA. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON CST /11 AM MST/ MONDAY FOR NEZ007- 009-010-022>029-035>038-056>059-069>071. WIND CHILL WARNING UNTIL NOON CST /11 AM MST/ MONDAY FOR NEZ004>006-008-094. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...MASEK LONG TERM...CLB AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
527 PM CST SUN DEC 8 2013 .SYNOPSIS... ISSUED AT 326 PM CST SUN DEC 8 2013 H5 ANALYSIS FROM THIS MORNING HAS A HIGHLY AMPLIFIED PATTERN ACROSS NOAM THIS MORNING WITH A RIDGE EXTENDING INTO THE GULF OF ALASKA. A CLOSED LOW WAS OVER WESTERN PORTIONS OF THE HUDSON BAY WITH A DEEP TROUGH OF LOW PRESSURE EXTENDING SSWD INTO THE ROCKIES AND SWRN US. NUMEROUS EMBEDDED SHORTWAVES WERE NOTED ACROSS THE WESTERN CONUS THIS MORNING. THE FIRST OVER SWRN WYOMING...WHICH IS CROSSING CENTRAL COLORADO AND IS EMERGING ONTO THE FRONT RANGES JUST SOUTH OF DENVER...PER SATELLITE AND RADAR IMAGERY. ANOTHER SHORTWAVE WAS LOCATED OVER SWRN SASKATCHEWAN AND SRN ALBERTA...AND A THIRD WAS NOTED OFF THE NRN CALIFORNIA COAST. AT THE SURFACE...AN AREA OF SNOW IN ASSOCIATION WITH THE FIRST SHORTWAVE...EXTENDED FROM AROUND LIMON COLORADO...NEWD TO FAR SOUTHWESTERN NEBRASKA. THE HEAVIEST SNOW PER RADAR IMAGERY EXTENDED FROM NEAR LIMON COLORADO TO NEAR IMPERIAL. THIS ACTIVITY HAS BEEN MOVING TO THE EAST NORTHEAST AND IS EXPECTED TO REMAIN MAINLY SOUTH OF THE FORECAST AREA THIS AFTERNOON. THE EXCEPTION IS ACROSS THE FAR SOUTHWESTERN COUNTIES WHERE 1 TO 2 INCHES IS POSSIBLE THIS AFTERNOON. ELSEWHERE...ANY ACCUMULATIONS ARE EXPECTED TO BE AN INCH OR LESS. AS OF 3 PM CST...UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES RANGED FROM 11 AT VALENTINE TO 17 AT OGALLALA. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 326 PM CST SUN DEC 8 2013 SHORT WAVE MOVING ACROSS THE NEB/KS BORDER...WHICH MODELS HAVE HANDLED FAIRLY WELL. LIGHT SNOW WILL BE TAPERING TO FLURRIES ACROSS PORTIONS OF SOUTHWEST AND CENTRAL NEBRASKA BEFORE ENDING LATER THIS EVENING. ADDITIONAL SNOWFALL COULD REACH UP TO THREE QUARTERS OF AN INCH...HOWEVER MOST AREAS IN THE SE CWA TO SEE A COUPLE OF TENTHS. CLEARING SKIES ARE ALREADY SEEN ON VISIBLE SAT ACROSS THE PANHANDLE AND NW NEB. HIGH PRESSURE WILL BEGIN TO NOSE DOWN INTO THE AREA TONIGHT...WHICH WILL COMBINE WITH THE SNOW PACK TO ALLOW FOR GOOD RADIATIONAL COOLING. RECENT LOWS HAVE BEEN BELOW GUIDANCE WHEN SKIES HAVE CLEARED...SO TOOK COOLER MAV GUIDANCE AND DROPPED A COUPLE OF DEGREES...WHICH MAYBE CONSERVATIVE FOR PORTIONS OF THE NW CWA...WHERE MORE THAN HALF A FOOT OF SNOW REMAINS ON THE GROUND. THIS PLACES LOWS IN THE -5 TO -15 DEGREE RANGE. NORTHWEST WINDS MOVING IN WITH THE CLEARING...ALTHOUGH THEY WILL BE DIMINISHING. THE COMBINATION OF LIGHT WINDS AND BITTER COLD TEMPS WILL ALLOW FOR WIND CHILLS TO FALL INTO THE -20 TO -30 RANGE...LOCALLY LOWER ACROSS NW ZONES. WILL GO WITH A WIND CHILL ADVISORY FOR ENTIRE CWA. TOMORROW MODELS HOLD 850 MB TEMPS FAIRLY STEADY...AND WITH MOSTLY SUNNY SKIES EXPECT HIGHS TO REBOUND A LITTLE WARMER THAN TODAY...HIGHS SHOULD REBOUND INTO THE TEENS TO NEAR 20. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 326 PM CST SUN DEC 8 2013 MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING CHALLENGES ARE TEMPERATURES...THEN LOW PRECIPITATION CHANCES FOR TUESDAY NIGHT. ON MONDAY NIGHT...A SURFACE TROUGH OF LOW PRESSURE WILL TRACK FROM THE CENTRAL PLAINS EAST INTO THE UPPER MIDWEST. LIMITED CAA WILL ACCOMPANY PASSAGE OF THE TROUGH. HOWEVER...IT WILL HELP TO KEEP THE LOW LEVEL WINDS MIXED ON MONDAY NIGHT...THUS MILDER TEMPERATURES ARE EXPECTED. ALBEIT...LOWS WILL STILL BE COLD WITH READINGS IN THE SINGLE DIGITS. ON TUESDAY...WESTERLY DOWNSLOPE WINDS WILL CONTINUE INCREASE SOMEWHAT TO 10 TO 15 MPH. DECIDED TO UNDERCUT GUIDANCE FOR HIGHS TUESDAY...BASED ON SNOW COVER AND LIMITED MIXING POTENTIAL. THIS LED TO HIGHS MAINLY IN THE 20S...WITH SOME TEMPS NEAR THE FREEZING MARK ACROSS THE FAR SOUTHWEST. ON TUESDAY NIGHT...AN ARCTIC COLD FRONT WILL BACK INTO NORTHERN AND NORTHEASTERN NEBRASKA WITH A NICE PV MAX ARRIVING OVERNIGHT. CROSS SECTIONS ACROSS NORTHERN NEBRASKA ARE INDICATIVE OF SOME WEAK LIFT IN THE DENDRITIC LAYER WHICH MAXES OUT AROUND 06Z WEDNESDAY. TOP DOWN SATURATION WILL HAVE TO OCCUR WITH ANY PCPN WHICH MAY FALL...SO WILL LIMIT POP MENTION TO SLIGHTS FOR NOW...AND KEEP POPS ACROSS THE NRN CWA AS CROSS SECTIONS NEVER MOISTEN UP ACROSS THE SRN CWA. ON WEDNESDAY SURFACE HIGH PRESSURE WILL BUILD INTO THE MID MISSOURI VALLEY. WINDS WILL SHIFT TO THE SOUTHWEST DURING THE AFTERNOON HOURS...AND WILL RECYCLE COLD AIR ACROSS THE FORECAST AREA. HIGHS WILL BE COLD...RANGING FROM THE MIDDLE TEENS IN THE NORTHEAST...TO THE UPPER 20S IN THE FAR SOUTHWEST. WEDNESDAY NIGHT THROUGH SUNDAY...THE MID RANGE MODEL SOLUTIONS CONTINUE TO INDICATE LOW AMPLITUDE WEST NORTHWESTERLY FLOW ACROSS THE CONUS FOR THE END OF THE WEEK INTO EARLY NEXT WEEK. BOTH THE ECMWF AND GFS SOLNS ARE TRENDING TOWARD THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EMBEDDED IN THE SRN STREAM TOWARD FRIDAY. BOTH SOLNS LIFT THIS ENERGY SOUTH OF THE AREA...SO A DRY FORECAST CONTINUES. AFTER TEMPERATURES TREND HIGHER FOR THURSDAY AND FRIDAY WITH HIGHS IN THE 30S...COOLER TEMPERATURES WILL ARRIVE ON FRIDAY NIGHT AS AN ARCTIC COLD FRONT BACKS INTO THE FORECAST AREA. HIGHS WILL BE COOLER IN THE 20S AND LOWER 30S SATURDAY...FOLLOWED BY 30S AND LOWER 40S FOR SUNDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 527 PM CST SUN DEC 8 2013 VFR IS EXPECTED ALL AREAS TONIGHT AND MONDAY. A BATCH OF MID LEVEL CLOUDS...CURRENTLY OVER NORTHEAST WY...WILL MOVE OVERHEAD TONIGHT FOLLOWED BY SOME CLEARING MONDAY MORNING AND SCATTERED HIGH CLOUDS THEREAFTER. NO FOG WAS INDICATED IN THE NAM OR HRRR MODELS TONIGHT. INDICATIONS ARE THE REINFORCING ARCTIC FRONT MOVING THROUGH THE FCST AREA WILL SCOUR ALL MOISTURE FROM AREA. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 9 PM CST /8 PM MST/ THIS EVENING TO NOON CST /11 AM MST/ MONDAY FOR NEZ004>010-022>029-035>038- 056>059-069>071-094. && $$ SYNOPSIS...CLB SHORT TERM...MASEK LONG TERM...CLB AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1005 PM EST SUN DEC 8 2013 .SYNOPSIS... A SYSTEM WILL BRING A ROUND OF LIGHT FREEZING DRIZZLE TONIGHT THROUGH MORNING. MONDAY NIGHT THROUGH THURSDAY...ARCTIC AIR WILL WORK INTO THE AREA. THIS WILL INCLUDE DEVELOPING ACCUMULATING LAKE EFFECT SNOW SHOWERS EAST OF THE GREAT LAKES. && .NEAR TERM /THROUGH MONDAY/... 1005 PM UPDATE... HV DELAYED PCPN FURTHER BY SVRL HRS AS NEPA IS SEEING VRY LITTLE PCPN ATTM, THO SRN TIER IS SEEING FLURRIES. KBUF 00Z RAOB STILL SHOWING DRY AIR IN THE LOWEST 200MB AND THIS IS BEING CONFIRMED BY OBS ACRS THE REGION. EMPHASIS NOW TURNS TO FRZG PCPN DRG THE OVRNGT HRS AS SNOW/SLEET DOES NOT APPEAR TO BE THE BIG CONCERN. ATMOS LOSES MOISTURE IN THE DENDRITE ZONE TONIGHT AS MOISTURE IN THE AREA IS GETTING THE SQUEEZE PLAY BTWN THE COASTAL LOW AND GREAT LKS LOW. THUS, HV UPDATED TO GO FRZG DRIZZLE AREAWIDE FOR TONIGHT WITH A GLAZE OF ICE EXPECTED BY MRNG. THUS WL KEEP THE ADVISORY GOING AS TEMPS RMN BLO FRZG AND ONLY VRY LGT QPF EXPECTED. PREV DISCUSSIONS BLO... 630 PM UPDATE... PRECIP IS TAKING QUITE AWHILE TO MV INTO FA AS IT SLOWLY WORKS ITS WAY THRU PA. ACRS NEPA, OBS ARE STILL REPORTING CIGS RANGING FM 6-10KFT AND HIGHER ACRS CNTRL NY. 18Z RAOB OUT OF KBUF SHOWING THE LOWEST 300MB STILL DRY, HELPING TO EVAPORATE QPF AS IT HEADS NWRD. APPEARS AS THO 18Z GFS BUFKIT SNDGS HV A BETTER HANDLE ON LOW-LVL DRY AIR WITH BLYR AT KAVP RMNG TOO DRY FOR SNOW THRU 00Z, WHEREAS NAM, RAP AND ARW SNDGS INDICATING SNOW SHUD HV BEEN FALLING FOR THE LAST SVRL HRS DOWN ACRS NEPA. THUS HV BACKED OFF ON POPS FOR EARLY THIS EVNG WITH CHC LIGHT SNOW IN NEPA NOT MVG IN FOR ANOTHER FEW HRS, SOMEWHERE BTWN 01Z AND 02Z. THIS AREA OF LIGHT SNOW WL GRADUALLY SPREAD NORTH MVG INTO SRN TIER BY 03Z AND OVRSPRD RMNDR OF THE AREA BY 06Z. QPF AMNTS EXPECTED TO BE VRY LGT WITH QPF TOTALS THRU MRNG < 0.10 INCHES. EXPECT SNOW TO CONT ACRS ENTIRE CWA THRU 06Z (A TAD LATER THAN PREVIOUSLY THOUGHT) BFR GRADUALLY MIXING WITH SLEET AND EVENTUALLY -FZRA/-FZDZ TWD DAYBREAK. EXPECT SNOW TO HANG ON LONGEST OVR NRN ONEIDA CNTY WHERE COLD AIR WL BE DEEPEST. HAVING SAID ALL THIS EXPECT JUST 1-2 INCHES OF SNOW AND SLEET ACCUMS, HIGHEST OVR EXTRM ERN SXNS FM MOHAWK VLY DOWN THRU WRN CATS. APPEARS LKLY THAT ALL AREAS WL SEE A GLAZE OF ICE BY MRNG, MAKING FOR HAZARDOUS TRAVEL DRG THE MRNG COMMUTE. 315 PM UPDATE... DOUBLE LOW SYSTEM...YET WE ARE IN BETWEEN...WITH ONE CENTER BY THE NORTHERN GREAT LAKES AND THE OTHER OFFSHORE OF NEW JERSEY. FORCING WITH THE SOUTHERN LOW HAS YIELDED A BAND OF HEAVY SNOW IN SOUTHEAST PA THROUGH NJ...AS ANYONE WATCHING THE PHILADELPHIA PRO FOOTBALL GAME CAN ATTEST. WE WILL STILL GET A PIECE OF THE SYSTEM...WITH TOP DOWN MOISTENING YIELDING A BATCH OF SNOW THIS EVENING SPREADING FROM SOUTHWEST TO NORTHEAST. HOWEVER...SHORTLY AFTER SNOW ARRIVES...SATURATED LAYER BECOMES SHALLOW TO POINT THAT TEMPERATURES WITHIN IT BECOME UNSUPPORTIVE OF ICE CRYSTAL FORMATION...SO QUICK SOUTH-TO-NORTH TRANSITION TO WINTRY MIX OF LIGHT SLEET AND FREEZING RAIN/DRIZZLE IS FORESEEN OVERNIGHT INTO EARLY MONDAY...AND EVENTUALLY PLAIN RAIN/DRIZZLE DURING THE DAY MONDAY. WINTER WEATHER ADVISORY FOR ENTIRE AREA STILL LOOKS GOOD YET AS PREVIOUSLY ADVERTISED THIS WILL DEFINITELY BE A LIGHT PRECIPITATION EVENT. IT HAPPENS TO INCLUDE LIGHT FREEZING RAIN/FREEZING DRIZZLE AND THUS THE POTENTIAL FOR HAZARDOUS TRAVEL CONDITIONS ON UNTREATED ROADS...NECESSITATING THE ADVISORY. ONLY FIGURING ON AN INCH OR LESS OF SNOW- SLEET ACCUMULATION /PERHAPS CLOSER TO 2 INCHES IN CATSKILLS TO ONEIDA COUNTY/...AND UP TO A TENTH OF AN INCH OF ICE ACCUMULATION...MOST PLACES LESS. NON-DIURNAL TEMPERATURES TONIGHT...SLOWLY CLIMBING FROM UPPER 20S THROUGH LOW 30S INTO MONDAY MORNING...EVENTUALLY REACHING HIGHS OF MID 30S TO LOW 40S DURING THE DAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... 130 PM UPDATE... COLD AIR ADVECTION WILL DOMINATE THE SHORT TERM PERIOD...AS WELL AS DEVELOPMENT OF WESTERLY-FLOW LAKE EFFECT SNOW FOR SOME. DEPARTURE OF SYSTEM WELL TO OUR NORTHEAST...AS WELL AS SHALLOW MOISTURE PROFILE AND WEST-SOUTHWEST FLOW...WILL KEEP THINGS FAIRLY QUIET MONDAY NIGHT. INTO TUESDAY THOUGH...850MB TEMPERATURES WILL DIP INTO THE LOWER TO MID TEENS BELOW ZERO CELSIUS WHILE INVERSION WILL RISE TO DENDRITIC GROWTH LAYER...BEGINNING TO INITIATE BETTER LAKE RESPONSES. NOT EXPECTING HEAVY ACCUMULATIONS TUESDAY ITSELF WITH WSW FLOW KEEPING LAKE ONTARIO BAND MAINLY NORTH...YET PERHAPS STILL SKIMMING NORTHERN ONEIDA COUNTY. HOWEVER...LAKE ERIE BAND MAY ACTUALLY STRETCH WELL EAST INTO AT LEAST SOUTHERN TIER-FINGER LAKES FOR AT LEAST SCATTERED SNOW SHOWERS AND PERHAPS BRIEF HEAVIER BURSTS. LAKE EFFECT CONTINUES TO BE FAVORABLE TUESDAY NIGHT INTO WEDNESDAY...AS 1000-500MB THICKNESSES DROP FURTHER INTO THE MID 510S TO LOWER 520S DECAMETER RANGE. HIGHS WEDNESDAY ONLY 20S AREAWIDE. MODEL SOUNDINGS SUGGEST DENDRITIC GROWTH TEMPERATURES DOMINATING THE 3-7 KFT AGL LAYER. PASSING SHORTWAVES THOUGH WILL FLUCTUATE LOW LEVEL WINDS...WHICH WILL PUSH THE BANDS AROUND AND ALSO COULD MIS ALIGN WINDS IN THE LOWEST LEVELS. WE WILL HAVE TO WATCH NORTHERN ONEIDA COUNTY CLOSELY IN MODEL TRENDS FOR POTENTIAL OF GETTING INVOLVED IN LAKE PROLIFIC ONTARIO SNOW BAND...WHICH MUCH IF NOT MOST OF THE TIME WILL REMAIN JUST TO THE NORTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 215 PM EST UPDATE... A VERY ACTIVE WEATHER PATTERN IS EXPECTED IN THE EXTENDED FORECAST. MINOR ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST AND LEANED TOWARDS WPC GUIDANCE. VERY BROAD UPPER LEVEL LOW WILL SLOWLY DRIFT NORTH AND EAST OF THE REGION RESULTING IN A MUCH COOLER AIR MASS OVER THE REGION... THUS LE SNOW SHOWERS WILL BE POSSIBLE THROUGH FRIDAY FOR CENTRAL NY. HIGH PRESSURE WILL BUILD ACROSS NEW ENGLAND THIS WEEKEND WHICH WILL HELP TEMPS CREEP CLOSER TOWARDS 32. WITH LARGE DIFFERENCE WITHIN GFS/ECMWF INTO THE WEEKEND KEPT PREVIOUS FORECAST WITH A SLIGHT CHANCE FOR SNOW SHOWERS. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... TERMINALS ARE ALL PRESENTLY VFR UNDER MID CLDS AS LIGHT SNOW MOVES IN FROM THE SW. THE HEAVIEST PRECIPITATION WILL REMAIN E AND S OF OUR TERMINALS. HOWEVER CIGS AND VSBYS WILL DETERIORATE BETWEEN 00Z AND 04Z FOR KAVP...KBGM...KELM AND KITH AS LIGHT SNOWS LOWER CIGS TO MVFR WITH MVFR TO PATCHY IFR VSBYS IN SN INITIALLY. FARTHER N VFR UNDER LWRG MID DECK THRU 6Z. AFTER 6Z...PTYPE BECOMES AN ISSUE FOR OUR TERMINALS IN SC NY AND NE PA AS CIGS AVERAGE MVFR WITH IFR SN. PRECIP WILL TURN OVER TO LIGHT FZDZ AND PL ACRS KITH...KBGM...KAVP...KELM BETWEEN 6Z AND 10Z. FARTHER N AT KSYR AND KRME MVFR LIGHT SNOW WILL MOVE IN MAINLY AFTER 6Z WITH THE CHANGEOVER TO FZDZ OCCURRING BETWEEN 10Z AND 13Z. ALL TERMINALS WILL TRANSITION TO RADZ BETWEEN 13Z AND 16Z WITH KRME AND KBGM HOLDING ON TO FZDZ THE LONGEST. AS THE WARMER AIR MOVES IN MON AM...CIGS WILL LOWER TO IFR AT KBGM/KRME AND KITH WITH MVFR REST OF TAFS. BY MON PM...CONDITIONS WILL GRADUALLY IMPROVE TO VFR UNDER SC MOST TAFS. KBGM/KRME LIKELY WILL HOLD ONTO MVFR CIG THRU THE DAY. OUTLOOK... MON NIGHT... CONDITIONS SLOWLY IMPROVING TO VFR AT KBGM/KRME. VFR REST OF TAFS. TUE/WED/THU...SCT MVFR SYR/RME IN LAKE EFFECT SNOW SHOWERS. VFR ELSEWHERE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR PAZ038>040- 043-044-047-048-072. NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR NYZ015>018- 022>025-044-045-055-056-062. WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR NYZ009-036- 037-046-057. && $$ SYNOPSIS...MDP/PVN NEAR TERM...MDP/PVN SHORT TERM...MDP LONG TERM...KAH AVIATION...DJN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 PM EST SUN DEC 8 2013 .SYNOPSIS... A SYSTEM WILL BRING A ROUND OF LIGHT MIXED PRECIPITATION TONIGHT INTO MONDAY MORNING...STARTING AS LIGHT SNOW THIS EVENING AND THEN TRANSITIONING TO LIGHT FREEZING RAIN...SLEET...AND FREEZING DRIZZLE OVERNIGHT. MONDAY NIGHT THROUGH THURSDAY...ARCTIC AIR WILL WORK INTO THE AREA. THIS WILL INCLUDE DEVELOPING ACCUMULATING LAKE EFFECT SNOW SHOWERS EAST OF THE GREAT LAKES. && .NEAR TERM /THROUGH MONDAY/... 630 PM UPDATE... PRECIP IS TAKING QUITE AWHILE TO MV INTO FA AS IT SLOWLY WORKS ITS WAY THRU PA. ACRS NEPA, OBS ARE STILL REPORTING CIGS RANGING FM 6-10KFT AND HIGHER ACRS CNTRL NY. 18Z RAOB OUT OF KBUF SHOWING THE LOWEST 300MB STILL DRY, HELPING TO EVAPORATE QPF AS IT HEADS NWRD. APPEARS AS THO 18Z GFS BUFKIT SNDGS HV A BETTER HANDLE ON LOW-LVL DRY AIR WITH BLYR AT KAVP RMNG TOO DRY FOR SNOW THRU 00Z, WHEREAS NAM, RAP AND ARW SNDGS INDICATING SNOW SHUD HV BEEN FALLING FOR THE LAST SVRL HRS DOWN ACRS NEPA. THUS HV BACKED OFF ON POPS FOR EARLY THIS EVNG WITH CHC LIGHT SNOW IN NEPA NOT MVG IN FOR ANOTHER FEW HRS, SOMEWHERE BTWN 01Z AND 02Z. THIS AREA OF LIGHT SNOW WL GRADUALLY SPREAD NORTH MVG INTO SRN TIER BY 03Z AND OVRSPRD RMNDR OF THE AREA BY 06Z. QPF AMNTS EXPECTED TO BE VRY LGT WITH QPF TOTALS THRU MRNG < 0.10 INCHES. EXPECT SNOW TO CONT ACRS ENTIRE CWA THRU 06Z (A TAD LATER THAN PREVIOUSLY THOUGHT) BFR GRADUALLY MIXING WITH SLEET AND EVENTUALLY -FZRA/-FZDZ TWD DAYBREAK. EXPECT SNOW TO HANG ON LONGEST OVR NRN ONEIDA CNTY WHERE COLD AIR WL BE DEEPEST. HAVING SAID ALL THIS EXPECT JUST 1-2 INCHES OF SNOW AND SLEET ACCUMS, HIGHEST OVR EXTRM ERN SXNS FM MOHAWK VLY DOWN THRU WRN CATS. APPEARS LKLY THAT ALL AREAS WL SEE A GLAZE OF ICE BY MRNG, MAKING FOR HAZARDOUS TRAVEL DRG THE MRNG COMMUTE. PREV DISCUSSION BLO... 315 PM UPDATE... DOUBLE LOW SYSTEM...YET WE ARE IN BETWEEN...WITH ONE CENTER BY THE NORTHERN GREAT LAKES AND THE OTHER OFFSHORE OF NEW JERSEY. FORCING WITH THE SOUTHERN LOW HAS YIELDED A BAND OF HEAVY SNOW IN SOUTHEAST PA THROUGH NJ...AS ANYONE WATCHING THE PHILADELPHIA PRO FOOTBALL GAME CAN ATTEST. WE WILL STILL GET A PIECE OF THE SYSTEM...WITH TOP DOWN MOISTENING YIELDING A BATCH OF SNOW THIS EVENING SPREADING FROM SOUTHWEST TO NORTHEAST. HOWEVER...SHORTLY AFTER SNOW ARRIVES...SATURATED LAYER BECOMES SHALLOW TO POINT THAT TEMPERATURES WITHIN IT BECOME UNSUPPORTIVE OF ICE CRYSTAL FORMATION...SO QUICK SOUTH-TO-NORTH TRANSITION TO WINTRY MIX OF LIGHT SLEET AND FREEZING RAIN/DRIZZLE IS FORESEEN OVERNIGHT INTO EARLY MONDAY...AND EVENTUALLY PLAIN RAIN/DRIZZLE DURING THE DAY MONDAY. WINTER WEATHER ADVISORY FOR ENTIRE AREA STILL LOOKS GOOD YET AS PREVIOUSLY ADVERTISED THIS WILL DEFINITELY BE A LIGHT PRECIPITATION EVENT. IT HAPPENS TO INCLUDE LIGHT FREEZING RAIN/FREEZING DRIZZLE AND THUS THE POTENTIAL FOR HAZARDOUS TRAVEL CONDITIONS ON UNTREATED ROADS...NECESSITATING THE ADVISORY. ONLY FIGURING ON AN INCH OR LESS OF SNOW- SLEET ACCUMULATION /PERHAPS CLOSER TO 2 INCHES IN CATSKILLS TO ONEIDA COUNTY/...AND UP TO A TENTH OF AN INCH OF ICE ACCUMULATION...MOST PLACES LESS. NON-DIURNAL TEMPERATURES TONIGHT...SLOWLY CLIMBING FROM UPPER 20S THROUGH LOW 30S INTO MONDAY MORNING...EVENTUALLY REACHING HIGHS OF MID 30S TO LOW 40S DURING THE DAY. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... 130 PM UPDATE... COLD AIR ADVECTION WILL DOMINATE THE SHORT TERM PERIOD...AS WELL AS DEVELOPMENT OF WESTERLY-FLOW LAKE EFFECT SNOW FOR SOME. DEPARTURE OF SYSTEM WELL TO OUR NORTHEAST...AS WELL AS SHALLOW MOISTURE PROFILE AND WEST-SOUTHWEST FLOW...WILL KEEP THINGS FAIRLY QUIET MONDAY NIGHT. INTO TUESDAY THOUGH...850MB TEMPERATURES WILL DIP INTO THE LOWER TO MID TEENS BELOW ZERO CELSIUS WHILE INVERSION WILL RISE TO DENDRITIC GROWTH LAYER...BEGINNING TO INITIATE BETTER LAKE RESPONSES. NOT EXPECTING HEAVY ACCUMULATIONS TUESDAY ITSELF WITH WSW FLOW KEEPING LAKE ONTARIO BAND MAINLY NORTH...YET PERHAPS STILL SKIMMING NORTHERN ONEIDA COUNTY. HOWEVER...LAKE ERIE BAND MAY ACTUALLY STRETCH WELL EAST INTO AT LEAST SOUTHERN TIER-FINGER LAKES FOR AT LEAST SCATTERED SNOW SHOWERS AND PERHAPS BRIEF HEAVIER BURSTS. LAKE EFFECT CONTINUES TO BE FAVORABLE TUESDAY NIGHT INTO WEDNESDAY...AS 1000-500MB THICKNESSES DROP FURTHER INTO THE MID 510S TO LOWER 520S DECAMETER RANGE. HIGHS WEDNESDAY ONLY 20S AREAWIDE. MODEL SOUNDINGS SUGGEST DENDRITIC GROWTH TEMPERATURES DOMINATING THE 3-7 KFT AGL LAYER. PASSING SHORTWAVES THOUGH WILL FLUCTUATE LOW LEVEL WINDS...WHICH WILL PUSH THE BANDS AROUND AND ALSO COULD MIS ALIGN WINDS IN THE LOWEST LEVELS. WE WILL HAVE TO WATCH NORTHERN ONEIDA COUNTY CLOSELY IN MODEL TRENDS FOR POTENTIAL OF GETTING INVOLVED IN LAKE PROLIFIC ONTARIO SNOW BAND...WHICH MUCH IF NOT MOST OF THE TIME WILL REMAIN JUST TO THE NORTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 215 PM EST UPDATE... A VERY ACTIVE WEATHER PATTERN IS EXPECTED IN THE EXTENDED FORECAST. MINOR ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST AND LEANED TOWARDS WPC GUIDANCE. VERY BROAD UPPER LEVEL LOW WILL SLOWLY DRIFT NORTH AND EAST OF THE REGION RESULTING IN A MUCH COOLER AIR MASS OVER THE REGION... THUS LE SNOW SHOWERS WILL BE POSSIBLE THROUGH FRIDAY FOR CENTRAL NY. HIGH PRESSURE WILL BUILD ACROSS NEW ENGLAND THIS WEEKEND WHICH WILL HELP TEMPS CREEP CLOSER TOWARDS 32. WITH LARGE DIFFERENCE WITHIN GFS/ECMWF INTO THE WEEKEND KEPT PREVIOUS FORECAST WITH A SLIGHT CHANCE FOR SNOW SHOWERS. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... TERMINALS ARE ALL PRESENTLY VFR UNDER MID CLDS AS LIGHT SNOW MOVES IN FROM THE SW. THE HEAVIEST PRECIPITATION WILL REMAIN E AND S OF OUR TERMINALS. HOWEVER CIGS AND VSBYS WILL DETERIORATE BETWEEN 00Z AND 04Z FOR KAVP...KBGM...KELM AND KITH AS LIGHT SNOWS LOWER CIGS TO MVFR WITH MVFR TO PATCHY IFR VSBYS IN SN INITIALLY. FARTHER N VFR UNDER LWRG MID DECK THRU 6Z. AFTER 6Z...PTYPE BECOMES AN ISSUE FOR OUR TERMINALS IN SC NY AND NE PA AS CIGS AVERAGE MVFR WITH IFR SN. PRECIP WILL TURN OVER TO LIGHT FZDZ AND PL ACRS KITH...KBGM...KAVP...KELM BETWEEN 6Z AND 10Z. FARTHER N AT KSYR AND KRME MVFR LIGHT SNOW WILL MOVE IN MAINLY AFTER 6Z WITH THE CHANGEOVER TO FZDZ OCCURRING BETWEEN 10Z AND 13Z. ALL TERMINALS WILL TRANSITION TO RADZ BETWEEN 13Z AND 16Z WITH KRME AND KBGM HOLDING ON TO FZDZ THE LONGEST. AS THE WARMER AIR MOVES IN MON AM...CIGS WILL LOWER TO IFR AT KBGM/KRME AND KITH WITH MVFR REST OF TAFS. BY MON PM...CONDITIONS WILL GRADUALLY IMPROVE TO VFR UNDER SC MOST TAFS. KBGM/KRME LIKELY WILL HOLD ONTO MVFR CIG THRU THE DAY. OUTLOOK... MON NIGHT... CONDITIONS SLOWLY IMPROVING TO VFR AT KBGM/KRME. VFR REST OF TAFS. TUE/WED/THU...SCT MVFR SYR/RME IN LAKE EFFECT SNOW SHOWERS. VFR ELSEWHERE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR PAZ038>040- 043-044-047-048-072. NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR NYZ015>018- 022>025-044-045-055-056. WINTER WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR NYZ062. WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR NYZ009-036- 037-046-057. && $$ SYNOPSIS...MDP NEAR TERM...MDP/PVN SHORT TERM...MDP LONG TERM...KAH AVIATION...DJN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
118 PM EST SAT DEC 7 2013 .SYNOPSIS... LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO SUNDAY MORNING EAST OF LAKE ONTARIO...WHILE THE REMAINDER OF THE AREA WILL SEE GENERALLY FAIR AND DRY WEATHER. THE NEXT STORM SYSTEM WILL BRING ANOTHER ROUND OF MIXED PRECIPITATION SUNDAY NIGHT AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... 930 AM UPDATE... VISIBLE SATELITE IMAGERY SHOWG STRATOCUMULUS ACRS A LARGE PART OF NRN...CNTRL AND WRN PA AND PARTS OF SW NY AND NRN AND ERN NY. THE LOW-LEVEL FLOW WILL BE ARND 280-290 DEGREES TODAY AND DIRECT LAKE EFFECT MOISTURE INTO NC NY FROM LAKE ONTARIO AND INTO SW NY FROM LAKE ERIE. LAKE ONTARIO WATER TEMPERATURES ARE RUNNING ARND 8C ON THE WRN END AND WITH 850 MB TEMPS AT -14C OR SO WE HAVE A 22C DIFFERNTIAL WHICH IS DECENT. HOWEVER...MODELS VARY ON THE AMNT OF LOW-LEVEL MOISTURE COMING ACRS THE LAKE. THE GFS IS DRIER HAVING SFC DWPTS ARND 20F WITH THE RAP AND NAM HAVING SFC DWPTS IN THE MID TO UPPER 20S. THIS LEADS TO VARIATIONS IN THE SOUNDINGS AND LES POTENTIAL. THE NAM/RAP WUD SUGGEST A POTENTIAL LAKE EFFECT SNOW BAND AND MAYBE A FEW INCHES ACCUMULATION OR MORE. THE GFS IS TOO DRY AND WE WUD SEE MAINLY LIGHTER ACC/S. THERE ALSO WAS SOME SHEAR BELOW THE INVERSION TOO WHICH ALSO GOES AGAINST ADVY AMNTS. SO FOR NOW WILL KEEP PREVIOUS FCST OF 1-3 INCHES DOWNWIND OF LAKE ONTARIO WITH THE HIGHEST AMNTS ALONG THE THRUWAY CORRIDOR. WILL KEEP FLURRIES FOR SW NY COUNTIES OF STEUBEN/YATES AND PARTS OF CHEMUNG AND EVEN BRADFORD PA THIS PM. OTHERWISE WILL SEE PC TO MC SKIES INTO TONIGHT. FOR TONIGHT...THE LES CONTINUES DOWNWIND OF LAKE ONTARIO AND LIKELY CONTRACTS BACK TWD LAKE ERIE SPARING STUEBEN CO DUE TO WEAKER WINDS. SO WILL KEEP LES GOING IN NC NY TONIGHT AND TAPER OFF THE FLURRIES IN SW NY COUNTIES. OTHERWISE PC REST OF AREA. PREVIOUS DSCN... 3 AM UPDATE... STEADY PRECIPITATION HAS NOW MOVED WELL SE OF THE AREA INTO SRN NJ. LIGHT SNOW CONTINUES WITH LITTLE ACCUMULATION EARLY THIS MORNING ENDING BY 12Z. DRIER AIR QUICKLY COMING EAST INTO NY AND PA AS SEEN ON THE RADAR MOSAIC. BEHIND THIS COLDER AIR ON A WNW LOW LEVEL FLOW WILL START THE LAKE EFFECT MACHINE. WITH TEMPERATURE DIFFERENTIAL MARGINAL AND SYNOPTIC MOISTURE GONE LES WILL BE WEAK. MOSTLY 1 OR 2 INCHES PER 12 HOURS...DESPITE A SINGLE BAND ALONG THE THRUWAY IN ONONDAGA...MADISON...AND ONEIDA. TODAY THE BAND WILL HAVE A GEORGIAN BAY CONNECTION ON A 290 FLOW. MODEL DIFFERENCES TONIGHT ON WHEN THE BAND WILL SHIFT INTO JUST ONEIDA AS THE FLOW SHIFTS TO 270. ATTM IT LOOKS LIKE A LULL LATE EVE THEN WITH THE BAND DOWN THE LENGTH OF LAKE ONTARIO A WEAK RESURGENCE LATE TONIGHT INTO SUNDAY MORNING. THE BAND WILL BE FIGHTING DRIER SINKING AIR WITH A LARGE SFC HIGH MOVING EAST TO BE OVER THE NE US SUN AFTN. SNOW AMOUNTS WELL BELOW ADVISORY CRITERIA BUT BRIEF BURSTS COULD PUT DOWN HALF AN INCH PER HOUR. OUTSIDE OF THE LAKE EFFECT BAND IT SHOULD BE DRY WITH DECREASING CLOUD COVER TODAY INCREASING LATE TONIGHT. DO NOT EXPECT A LAKE ERIE SNOW BAND TO MAKE IT INTO STEUBEN COUNTY. SHORT FETCH AND NO CONNECTION. RADARS UPSTREAM NOT SHOWING MUCH FOR LAKE EFFECT AND LITTLE INLAND EXTENT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 3 AM UPDATE... SUNDAY HIGH PRESSURE WILL TAKE CONTROL VERY BREIFLY BEFORE A WEAK STORM MOVES NORTHEAST INTO THE AREA SUNDAY EVENING. PRECIP WILL START AS SNOW BUT CHANGEOVER TO SLEET AND FREEZING RAIN QUICKLY DURING THE OVERNIGHT AND MONDAY MORNING. MODELS KEEP QPF LOW WITH LESS THAN TWO TENTHS NORTH AND MAYBE A THIRD OF AN INCH IN THE FAR SOUTH. AT THIS EARLY POINT...SNOWFALL WILL BE MOSTLY UNDER 2 INCHES. MAYBE A LITTLE MORE IN THE SOUTHERN TUG OF ONEIDA COUNTY CLOSER TO THE COLDER AIR AND OROGRAPHIC LIFT. THE BIGGER PROBLEM WILL BE FREEZING RAIN FOR MUCH OF THE AREA. LIKE THE LAST EVENT THE HIGHEST AMOUNTS POSSIBLY UP TO A TENTH OF AN INCH AT HIGHER ELEVEATIONS IN THE POCONOS. BY NOON MONDAY SFC TEMPS WILL BE ABOVE FREEZING. ALSO BY THAT TIME STEADY PRECIP WILL HAVE LIFTED NE OUT OF THE AREA. MON AFTN INTO MON NGT A FEW LINGERING SHOWERS WILL CHANGE FROM RAIN TO SNOW. CAA TOO COULD SET OFF SOME LAKE EFFECT BUT FLOW SHOULD KEEP THE HEAVIEST OF THAT NORTH OF THE CWA EAST OF LAKE ONTARIO. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE MED RNG WILL BE DOMINATED BY LAKE EFFECT SNOW...MODULATED BY PASSING S/WV`S AND ASSCD SFC TROFS. MDLS SHOW ONE PASSING ON TUE...AND ANOTHER ONE ON THURSDAY. AFTER THIS TIME...MED RNG GUIDANCE DIVERGES WITH GFS SHOWING RIDGING WHILE THE EURO DROPS DOWN ANOTHER CDFNT. GIVEN THIS...WE DEFAULTED TO WPC FOR THE LATTER PDS...BUT MODIFIED CLD/POPS FIELDS TO SHOW LAKE EFFECT POTNL THRU MID/LATE WEEK. BOTTOM LINE IS COLD TEMPS AND PDS OF LAKE EFECT SNOW ACRS FAR NRN ZONES...AND PSBLY SOME -SHSN ACRS THE SRN TIER AND NRN PA DUE TO INFLUENCE OF LAKE ERIE. GFS PROFILES SUGGEST POTNL FOR SIG LES SNOW ACCUMS ACRS THE FAR NRN ZONES. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... LAKE EFFECT SNOW SHOWERS TO THE E AND SE OF LAKE ONTARIO WILL BE THE MAIN WEATHER FOCUS ACRS THE BGM CWA THIS FCST PD. RME WILL BE THE MOST AFFECTED WITH IFR/MVFR THIS AFTN INTO THE OVRNGT HRS (AND BRIEF PDS OF BLO ALT MINS)...WITH SOME IMPRVMNT AFTER 06Z AS WRLY FLOW/SNOW SHOWERS BEGIN TO WEAKEN. SYR SHUD BE ON THE SRN PERIPHERY OF THIS ACTIVITY THIS AFTN AND EVNG...WITH OCNL MVFR CONDITIONS. ELSEWHERE ACRS CNTRL NY AND NE PA...VFR WILL PREVAIL THIS AFTN INTO THE OVRNGT HRS...WITH VFR ALL SITES XPCTD ON SUN. WINDS THIS AFTN W TO NW 10-15 KTS...DIMINISHING THIS EVNG AND BCMG L&V ON SUN MRNG. OUTLOOK... SUN NGT/MON...WDSPRD IFR/MVFR MIXED PCPN AND SHRA. TUE/WED/THU...SCT MVFR SYR/RME IN LAKE EFFECT SNOW SHOWERS. VFR ELSEWHERE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN/TAC NEAR TERM...DJN SHORT TERM...TAC LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
116 PM EST SAT DEC 7 2013 .SYNOPSIS... LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO SUNDAY MORNING EAST OF LAKE ONTARIO...WHILE THE REMAINDER OF THE AREA WILL SEE GENERALLY FAIR AND DRY WEATHER. THE NEXT STORM SYSTEM WILL BRING ANOTHER ROUND OF MIXED PRECIPITATION SUNDAY NIGHT AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... 930 AM UPDATE... VISIBLE SATELITE IMAGERY SHOWG STRATOCUMULUS ACRS A LARGE PART OF NRN...CNTRL AND WRN PA AND PARTS OF SW NY AND NRN AND ERN NY. THE LOW-LEVEL FLOW WILL BE ARND 280-290 DEGREES TODAY AND DIRECT LAKE EFFECT MOISTURE INTO NC NY FROM LAKE ONTARIO AND INTO SW NY FROM LAKE ERIE. LAKE ONTARIO WATER TEMPERATURES ARE RUNNING ARND 8C ON THE WRN END AND WITH 850 MB TEMPS AT -14C OR SO WE HAVE A 22C DIFFERNTIAL WHICH IS DECENT. HOWEVER...MODELS VARY ON THE AMNT OF LOW-LEVEL MOISTURE COMING ACRS THE LAKE. THE GFS IS DRIER HAVING SFC DWPTS ARND 20F WITH THE RAP AND NAM HAVING SFC DWPTS IN THE MID TO UPPER 20S. THIS LEADS TO VARIATIONS IN THE SOUNDINGS AND LES POTENTIAL. THE NAM/RAP WUD SUGGEST A POTENTIAL LAKE EFFECT SNOW BAND AND MAYBE A FEW INCHES ACCUMULATION OR MORE. THE GFS IS TOO DRY AND WE WUD SEE MAINLY LIGHTER ACC/S. THERE ALSO WAS SOME SHEAR BELOW THE INVERSION TOO WHICH ALSO GOES AGAINST ADVY AMNTS. SO FOR NOW WILL KEEP PREVIOUS FCST OF 1-3 INCHES DOWNWIND OF LAKE ONTARIO WITH THE HIGHEST AMNTS ALONG THE THRUWAY CORRIDOR. WILL KEEP FLURRIES FOR SW NY COUNTIES OF STEUBEN/YATES AND PARTS OF CHEMUNG AND EVEN BRADFORD PA THIS PM. OTHERWISE WILL SEE PC TO MC SKIES INTO TONIGHT. FOR TONIGHT...THE LES CONTINUES DOWNWIND OF LAKE ONTARIO AND LIKELY CONTRACTS BACK TWD LAKE ERIE SPARING STUEBEN CO DUE TO WEAKER WINDS. SO WILL KEEP LES GOING IN NC NY TONIGHT AND TAPER OFF THE FLURRIES IN SW NY COUNTIES. OTHERWISE PC REST OF AREA. PREVIOUS DSCN... 3 AM UPDATE... STEADY PRECIPITATION HAS NOW MOVED WELL SE OF THE AREA INTO SRN NJ. LIGHT SNOW CONTINUES WITH LITTLE ACCUMULATION EARLY THIS MORNING ENDING BY 12Z. DRIER AIR QUICKLY COMING EAST INTO NY AND PA AS SEEN ON THE RADAR MOSAIC. BEHIND THIS COLDER AIR ON A WNW LOW LEVEL FLOW WILL START THE LAKE EFFECT MACHINE. WITH TEMPERATURE DIFFERENTIAL MARGINAL AND SYNOPTIC MOISTURE GONE LES WILL BE WEAK. MOSTLY 1 OR 2 INCHES PER 12 HOURS...DESPITE A SINGLE BAND ALONG THE THRUWAY IN ONONDAGA...MADISON...AND ONEIDA. TODAY THE BAND WILL HAVE A GEORGIAN BAY CONNECTION ON A 290 FLOW. MODEL DIFFERENCES TONIGHT ON WHEN THE BAND WILL SHIFT INTO JUST ONEIDA AS THE FLOW SHIFTS TO 270. ATTM IT LOOKS LIKE A LULL LATE EVE THEN WITH THE BAND DOWN THE LENGTH OF LAKE ONTARIO A WEAK RESURGENCE LATE TONIGHT INTO SUNDAY MORNING. THE BAND WILL BE FIGHTING DRIER SINKING AIR WITH A LARGE SFC HIGH MOVING EAST TO BE OVER THE NE US SUN AFTN. SNOW AMOUNTS WELL BELOW ADVISORY CRITERIA BUT BRIEF BURSTS COULD PUT DOWN HALF AN INCH PER HOUR. OUTSIDE OF THE LAKE EFFECT BAND IT SHOULD BE DRY WITH DECREASING CLOUD COVER TODAY INCREASING LATE TONIGHT. DO NOT EXPECT A LAKE ERIE SNOW BAND TO MAKE IT INTO STEUBEN COUNTY. SHORT FETCH AND NO CONNECTION. RADARS UPSTREAM NOT SHOWING MUCH FOR LAKE EFFECT AND LITTLE INLAND EXTENT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 3 AM UPDATE... SUNDAY HIGH PRESSURE WILL TAKE CONTROL VERY BREIFLY BEFORE A WEAK STORM MOVES NORTHEAST INTO THE AREA SUNDAY EVENING. PRECIP WILL START AS SNOW BUT CHANGEOVER TO SLEET AND FREEZING RAIN QUICKLY DURING THE OVERNIGHT AND MONDAY MORNING. MODELS KEEP QPF LOW WITH LESS THAN TWO TENTHS NORTH AND MAYBE A THIRD OF AN INCH IN THE FAR SOUTH. AT THIS EARLY POINT...SNOWFALL WILL BE MOSTLY UNDER 2 INCHES. MAYBE A LITTLE MORE IN THE SOUTHERN TUG OF ONEIDA COUNTY CLOSER TO THE COLDER AIR AND OROGRAPHIC LIFT. THE BIGGER PROBLEM WILL BE FREEZING RAIN FOR MUCH OF THE AREA. LIKE THE LAST EVENT THE HIGHEST AMOUNTS POSSIBLY UP TO A TENTH OF AN INCH AT HIGHER ELEVEATIONS IN THE POCONOS. BY NOON MONDAY SFC TEMPS WILL BE ABOVE FREEZING. ALSO BY THAT TIME STEADY PRECIP WILL HAVE LIFTED NE OUT OF THE AREA. MON AFTN INTO MON NGT A FEW LINGERING SHOWERS WILL CHANGE FROM RAIN TO SNOW. CAA TOO COULD SET OFF SOME LAKE EFFECT BUT FLOW SHOULD KEEP THE HEAVIEST OF THAT NORTH OF THE CWA EAST OF LAKE ONTARIO. && .LONG TERM /TUESDAY THROUGH SATURDAY/... THE MED RNG WILL BE DOMINATED BY LAKE EFFECT SNOW...MODULATED BY PASSING S/WV`S AND ASSCD SFC TROFS. MDLS SHOW ONE PASSING ON TUE...AND ANOTHER ONE ON THURSDAY. AFTER THIS TIME...MED RNG GUIDANCE DIVERGES WITH GFS SHOWING RIDGING WHILE THE EURO DROPS DOWN ANOTHER CDFNT. GIVEN THIS...WE DEFAULTED TO WPC FOR THE LATTER PDS...BUT MODIFIED CLD/POPS FIELDS TO SHOW LAKE EFFECT POTNL THRU MID/LATE WEEK. BOTTOM LINE IS COLD TEMPS AND PDS OF LAKE EFECT SNOW ACRS FAR NRN ZONES...AND PSBLY SOME -SHSN ACRS THE SRN TIER AND NRN PA DUE TO INFLUENCE OF LAKE ERIE. GFS PROFILES SUGGEST POTNL FOR SIG LES SNOW ACCUMS ACRS THE FAR NRN ZONES. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... LAKE EFFECT SNOW SHOWERS TO THE E AND SE OF LAKE ONTARIO WILL BE THE MAIN WEATHER FOCUS ACRS THE BGM CWA THIS FCST PD. RME WILL BE THE MOST AFFECTED WITH IFR/MVFR THIS AFTN INTO THE OVRNGT HRS (AND BRIEF PDS OF BLO ALT MINS)...WITH SOME IMPRVMNT AFTER 06Z AS WRLY FLOW.SNOW SHOWERS BEGIN TO WEAKEN. SYR SHUD BE ON THE SRN PERIPHERY OF THIS ACTIVITY THIS AFTN AND EVNG...WITH OCNL MVFR CONDITIONS. ELSEWHERE ACRS CNTRL NY AND NE PA...VFR WILL PREVAIL THIS AFTN INTO THE OVRNGT HRS...WITH VFR ALL SITES XPCTD ON SUN. WINDS THIS AFTN W TO NE 10-15 KTS...DIMINISHING THIS EVNG AND BCMG L&V ON SUN MRNG. OUTLOOK... SUN NGT/MON...WDSPRD IFR/MVFR MIXED PCPN AND SHRA. TUE/WED/THU...SCT MVFR SYR/RME IN LAKE EFFECT SNOW SHOWERS. VFR ELSEWHERE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN/TAC NEAR TERM...DJN SHORT TERM...TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
944 AM EST SAT DEC 7 2013 .SYNOPSIS... LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO SUNDAY MORNING EAST OF LAKE ONTARIO...WHILE THE REMAINDER OF THE AREA WILL SEE GENERALLY FAIR AND DRY WEATHER. THE NEXT STORM SYSTEM WILL BRING ANOTHER ROUND OF MIXED PRECIPITATION SUNDAY NIGHT AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/... 930 AM UPDATE... VISIBLE SATELITE IMAGERY SHOWG STRATOCUMULUS ACRS A LARGE PART OF NRN...CNTRL AND WRN PA AND PARTS OF SW NY AND NRN AND ERN NY. THE LOW-LEVEL FLOW WILL BE ARND 280-290 DEGREES TODAY AND DIRECT LAKE EFFECT MOISTURE INTO NC NY FROM LAKE ONTARIO AND INTO SW NY FROM LAKE ERIE. LAKE ONTARIO WATER TEMPERATURES ARE RUNNING ARND 8C ON THE WRN END AND WITH 850 MB TEMPS AT -14C OR SO WE HAVE A 22C DIFFERNTIAL WHICH IS DECENT. HOWEVER...MODELS VARY ON THE AMNT OF LOW-LEVEL MOISTURE COMING ACRS THE LAKE. THE GFS IS DRIER HAVING SFC DWPTS ARND 20F WITH THE RAP AND NAM HAVING SFC DWPTS IN THE MID TO UPPER 20S. THIS LEADS TO VARIATIONS IN THE SOUNDINGS AND LES POTENTIAL. THE NAM/RAP WUD SUGGEST A POTENTIAL LAKE EFFECT SNOW BAND AND MAYBE A FEW INCHES ACCUMULATION OR MORE. THE GFS IS TOO DRY AND WE WUD SEE MAINLY LIGHTER ACC/S. THERE ALSO WAS SOME SHEAR BELOW THE INVERSION TOO WHICH ALSO GOES AGAINST ADVY AMNTS. SO FOR NOW WILL KEEP PREVIOUS FCST OF 1-3 INCHES DOWNWIND OF LAKE ONTARIO WITH THE HIGHEST AMNTS ALONG THE THRUWAY CORRIDOR. WILL KEEP FLURRIES FOR SW NY COUNTIES OF STEUBEN/YATES AND PARTS OF CHEMUNG AND EVEN BRADFORD PA THIS PM. OTHERWISE WILL SEE PC TO MC SKIES INTO TONIGHT. FOR TONIGHT...THE LES CONTINUES DOWNWIND OF LAKE ONTARIO AND LIKELY CONTRACTS BACK TWD LAKE ERIE SPARING STUEBEN CO DUE TO WEAKER WINDS. SO WILL KEEP LES GOING IN NC NY TONIGHT AND TAPER OFF THE FLURRIES IN SW NY COUNTIES. OTHERWISE PC REST OF AREA. PREVIOUS DSCN... 3 AM UPDATE... STEADY PRECIPITATION HAS NOW MOVED WELL SE OF THE AREA INTO SRN NJ. LIGHT SNOW CONTINUES WITH LITTLE ACCUMULATION EARLY THIS MORNING ENDING BY 12Z. DRIER AIR QUICKLY COMING EAST INTO NY AND PA AS SEEN ON THE RADAR MOSAIC. BEHIND THIS COLDER AIR ON A WNW LOW LEVEL FLOW WILL START THE LAKE EFFECT MACHINE. WITH TEMPERATURE DIFFERENTIAL MARGINAL AND SYNOPTIC MOISTURE GONE LES WILL BE WEAK. MOSTLY 1 OR 2 INCHES PER 12 HOURS...DESPITE A SINGLE BAND ALONG THE THRUWAY IN ONONDAGA...MADISON...AND ONEIDA. TODAY THE BAND WILL HAVE A GEORGIAN BAY CONNECTION ON A 290 FLOW. MODEL DIFFERENCES TONIGHT ON WHEN THE BAND WILL SHIFT INTO JUST ONEIDA AS THE FLOW SHIFTS TO 270. ATTM IT LOOKS LIKE A LULL LATE EVE THEN WITH THE BAND DOWN THE LENGTH OF LAKE ONTARIO A WEAK RESURGENCE LATE TONIGHT INTO SUNDAY MORNING. THE BAND WILL BE FIGHTING DRIER SINKING AIR WITH A LARGE SFC HIGH MOVING EAST TO BE OVER THE NE US SUN AFTN. SNOW AMOUNTS WELL BELOW ADVISORY CRITERIA BUT BRIEF BURSTS COULD PUT DOWN HALF AN INCH PER HOUR. OUTSIDE OF THE LAKE EFFECT BAND IT SHOULD BE DRY WITH DECREASING CLOUD COVER TODAY INCREASING LATE TONIGHT. DO NOT EXPECT A LAKE ERIE SNOW BAND TO MAKE IT INTO STEUBEN COUNTY. SHORT FETCH AND NO CONNECTION. RADARS UPSTREAM NOT SHOWING MUCH FOR LAKE EFFECT AND LITTLE INLAND EXTENT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 3 AM UPDATE... SUNDAY HIGH PRESSURE WILL TAKE CONTROL VERY BREIFLY BEFORE A WEAK STORM MOVES NORTHEAST INTO THE AREA SUNDAY EVENING. PRECIP WILL START AS SNOW BUT CHANGEOVER TO SLEET AND FREEZING RAIN QUICKLY DURING THE OVERNIGHT AND MONDAY MORNING. MODELS KEEP QPF LOW WITH LESS THAN TWO TENTHS NORTH AND MAYBE A THIRD OF AN INCH IN THE FAR SOUTH. AT THIS EARLY POINT...SNOWFALL WILL BE MOSTLY UNDER 2 INCHES. MAYBE A LITTLE MORE IN THE SOUTHERN TUG OF ONEIDA COUNTY CLOSER TO THE COLDER AIR AND OROGRAPHIC LIFT. THE BIGGER PROBLEM WILL BE FREEZING RAIN FOR MUCH OF THE AREA. LIKE THE LAST EVENT THE HIGHEST AMOUNTS POSSIBLY UP TO A TENTH OF AN INCH AT HIGHER ELEVEATIONS IN THE POCONOS. BY NOON MONDAY SFC TEMPS WILL BE ABOVE FREEZING. ALSO BY THAT TIME STEADY PRECIP WILL HAVE LIFTED NE OUT OF THE AREA. MON AFTN INTO MON NGT A FEW LINGERING SHOWERS WILL CHANGE FROM RAIN TO SNOW. CAA TOO COULD SET OFF SOME LAKE EFFECT BUT FLOW SHOULD KEEP THE HEAVIEST OF THAT NORTH OF THE CWA EAST OF LAKE ONTARIO. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 3 AM UPDATE...CURRENT EXTENDED IN GOOD SHAPE ONLY CHANGE WAS TO INCREASE POPS INTO THE LIKELY CATEGORY TUESDAY NIGHT THROUGH WEDNESDAY NIGHT OVER NRN ONEIDA COUNTY WHEN LAKE EFFECT SNOW LOOKS MOST PROBABLE DUE TO WELL ALIGNED FLOW. PREVIOUS DISC... TUESDAY THROUGH THURSDAY WILL BE DOMINATED BY COLD WESTERLY FLOW WITH SOME LAKE EFFECT SNOW DOWNSTREAM OF LAKES ONTARIO AND ERIE. A SHORT WAVE WILL PASS ACROSS THE AREA ON TUESDAY ACCOMPANIED BY SCATTERED SNOW SHOWERS AND FOLLOWED BY WHAT LOOKS LIKE A WELL- ORGANIZED AND ALIGNED WESTERLY FLOW LAKE EFFECT SNOW EVENT WEDNESDAY INTO THURSDAY. TOO EARLY FOR DETAILS BUT A POTENTIALLY SIGNIFICANT LAKE EFFECT SNOW EVENT DOES APPEAR POSSIBLE. OTHERWISE THE TUESDAY THROUGH THURSDAY PERIOD WILL BE RATHER QUIET FOR MOST OF OUR AREA WITH SCATTERED FLURRIES OR LIGHT SNOW SHOWERS AND UNSEASONABLY COLD TEMPERATURES. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... COLD NORTHWEST FLOW WILL PRODUCE MVFR/LOW VFR STRATO CU TODAY ACROSS ALL TERMINALS. AT KSYR, LAKE EFFECT SNOW SHOWERS WILL MAKE FOR MVFR SNOW SHOWERS THROUGH LATE AFTERNOON WHEN ACTIVITY WILL LIFT NORTH OF AREA AS LOW LEVEL FLOW BACKS. AT KRME, FLURRIES WITH MVFR/LOW VFR CIGS WILL PERSIST THROUGH LATE AFTERNOON WHEN FLOW WILL BECOME MORE FAVORABLE FOR MVFR SNOW SHOWERS THROUGH THE OVERNIGHT PERIOD. AT KITH/KELM/KBGM/KAVP, CONDITIONS OVERNIGHT SHOULD BE PRIMARILY VFR WITH SCATTERED CLOUDS AROUND 4K FT AS LOW LEVEL FLOW BACKS AND SOME LOW LEVEL DRYING OCCURS. NORTHWEST WINDS AROUND 10 KNOTS WITH GUSTS AROUND 15-18 KNOTS DECREASING TO 5 KNOTS THIS EVENING. OUTLOOK... SUN...VFR. SUN NGT/MON...WDSPRD IFR/MVFR IN RAIN AND MIXED PCPN. TUE/WED...SCT MVFR MAINLY SYR/RME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJN/TAC NEAR TERM...DJN SHORT TERM...TAC LONG TERM...MSE/RRM AVIATION...RRM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
644 AM EST SAT DEC 7 2013 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE THROUGH TODAY. CHILLY HIGH PRESSURE WILL BRING A DAMP AND COOL COUPLE OF DAYS. MONDAY WILL BRIEFLY TURN WARMER AGAIN BEFORE ANOTHER COLD FRONT PUSHES THROUGH ON TUESDAY WITH THE BEST CHANCE OF RAIN. THE REMAINDER OF THE FORECAST WILL BE COOLER AND DRIER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SATURDAY...THE SFC COLD FRONT CURRENTLY EXTENDING FROM ALLIGATOR RIVER ACROSS RDU TO CLT...WILL DROP TO THE SOUTH THIS MORNING AND REACH THE NORTHERN PORTIONS OF THE ILM CWA BY MID-MORNING. THE COLD FRONT WILL CONTINUE TO DROP SOUTH AND CLEAR THE ILM CWA BY MID TO LATE THIS AFTERNOON...VIA LATEST HRRR MODEL SFC WIND PLOTS. LOOKING AT LIGHT TO MODERATE RAIN SHOWERS AHEAD AND IMMEDIATELY ALONG THE COLD FRONT...GIVING WAY TO POST FRONTAL PCPN IN THE FORM OF STRATIFORM LIGHT RAINS AND DRIZZLE. THE SFC PRESSURE PATTERN LATER TONIGHT INTO SUNDAY WILL REFLECT A COLD AIR DAMMING EVENT WITH A NEARLY SATURATED ATMOSPHERE FROM THE SFC TO 700MB KEEPING SKIES CLOUDY AND THE CONTINUED THREAT OF THE AFOREMENTIONED PCPN. TODAYS MAX TEMPS WILL LIKELY OCCUR JUST PRIOR TO THE COLD FRONTAL PASSAGE...FOLLOWED BY DECENT CAA AND A RATHER STEADY DECLINE OF TEMPS AFTER ITS PASSAGE. THE COLD AIR WILL REMAIN QUITE SHALLOW AS EVIDENCED WITH MODEL PROGGED 1000-500 MB THICKNESS...IE. FROM 562-567DAM THIS MORNING TO ONLY 558-562DAM BY SUNRISE SUNDAY. AT THE SAME TIME...SFC TEMPS IN THE 60S TO AROUND 70 THIS MORNING ...WILL DROP INTO THE 50S THIS AFTERNOON...AND THROUGH THE 40S TONIGHT WITH UPPER 30S POSSIBLE ACROSS THE NW PORTIONS OF THE ILM CWA. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...THE SHORT TERM FORECAST CONTINUES TO BE HIGHLIGHTED BY CHANGEABLE CONDITIONS AS A COLD AIR WEDGE SUNDAY TRANSITIONS TO A WARM AND SOUTHWEST FLOW AHEAD OF A COLD FRONT MONDAY...ALL OF THIS UNDER A SOUTHWEST FLOW ALOFT. I HAVE MADE ONLY SMALL ADJUSTMENTS TO POPS TO WALK BACK VALUES FOR MONDAY AND INCREASE VALUES FOR MONDAY NIGHT AS THE MID LEVEL FORCING COUPLES WITH THE APPROACHING FRONT. DIDNOT FEEL CONFIDENT ENOUGH TO MAKE CHANGES TO SUNDAYS VALUES AS WE CONTINUE TO EMPHASIZE LOW QPF AMOUNTS. ONCE AGAIN LOW CONFIDENCE WITH REGARDS TO THE TEMPERATURE FORECAST ALTHOUGH IT IS WORTH NOTING GUIDANCE HAS BEEN QUITE STABLE WITH THE CHANGEABLE CONDITIONS. LEANED TOWARD THE LOWER MET GUIDANCE THROUGH THE PERIOD. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 3 AM SATURDAY...THE MAIN FEATURE FOR THE EXTENDED NOW SHIFTS TO THE FRONT MOVING ACROSS TUESDAY AND THE LATEST MEDIUM RANGE GUIDANCE AS WELL AS WPC CONTINUES TO ADVERTISE A LATE TUESDAY ARRIVAL. THE REMAINDER OF THE PERIOD WILL FEATURE HIGH PRESSURE BUILDING IN FROM THE WEST NORTHWEST AS A MODIFIED VERSION OF THE BITTER COLD AIRMASS NOW ACROSS THE PLAINS MOVES ACROSS. THE END OF THE PERIOD WILL SEE A VERY FAMILIAR FEATURE ESPECIALLY AS OF LATE WITH THE POSSIBLE DEVELOPMENT OF A WEAKLY FORCED COASTAL TROUGH. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 12Z...COLD FRONT MARCHING SOUTHWARD...EXPECTED TO REACH THE NORTHERN PORTION OF THE CWA SHORTLY AFTER TAF ISSUANCE. UPSTREAM STATIONS SHOW SPORADIC IFR CONDITIONS. THERE WILL BE A NOTICEABLE WIND SHIFT TO THE NORTH...TRANSITIONING IN A 1-2 HOUR TIME FRAME. THERE IS SOME LIFT ALONG THE FRONTAL BOUNDARY...BUT ITS MORE PARALLEL THAN PERPENDICULAR...SO MOST OF THE RAIN WILL BE FLEETING...ONLY ISOLATED RAIN/DRIZZLE THIS AFTERNOON. TEMPERATURES WILL FALL FROM MIDDAY THROUGH THE AFTERNOON HOURS. IFR WEDGE STRATUS IS EXPECTED THROUGH THE OVERNIGHT HOURS. EXTENDED OUTLOOK...UNSETTLED WEATHER THROUGH THE EXTENDED WITH INTERMITTENT IFR/MVFR CONDITIONS DUE TO A NEARLY STATIONARY FRONT. && .MARINE... NEAR TERM/THROUGH TONIGHT/... AS OF 345 AM SATURDAY...SCA REMAINS IN EFFECT FOR THE ILM COASTAL WATERS THROUGH MIDDAY SUNDAY TO ACCOUNT FOR THE POST FRONTAL N-NE SURGE AND RESULTANT SIGNIFICANT SEAS. MODELS INDICATE THE COLD FRONT WILL DROP FROM NNW TO SSE TODAY... WHICH IS NEARLY COMPARABLE TO A BACK-DOOR COLD FRONT. HOWEVER...AFTER THE PASSAGE OF THIS COLD FRONT...THE AREA WATERS WILL BE SUBJECT TO A DECENT PUSH OF POST FRONTAL N-NE WINDS FROM THE COMBINED EFFECTS OF A TIGHTENED SFC PG AND DECENT COLD AIR ADVECTION. THE LOCAL WATERS WILL BE LOOKING AT POST FRONTAL N-NE WINDS AT 15 TO 25 KT WITH GUSTS UP TO 30 KT LATE THIS AFTERNOON THROUGH TONIGHT. SIGNIFICANT SEAS INITIALLY IN THE 2 TO 4 FT RANGE MAINLY FROM THE EARLIER S-SW WIND WAVE ACTION...WILL BUILD TO A PEAK OF 4 TO 7 FT TONIGHT. AGAIN...WIND DRIVEN WAVES WILL DOMINATE THE SIGNIFICANT SEAS WITH AVERAGE PERIODS AROUND 5 SECONDS. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...MOST OF SUNDAY WILL SEE A NORTHEASTERLY FLOW ACROSS ALL WATERS WITH INITIAL SPEEDS OF 20-25 KNOTS MOSTLY TOWARD THE LOWER END OF THE RANGE. THE WEDGE WILL WEAKEN OVERNIGHT SUNDAY INTO MONDAY MORNING AS A SOUTH THEN SOUTHWEST FLOW DEVELOPS. SPEEDS WILL INCREASE TO 15-20 KNOTS ONCE AGAIN AND CONTINUE INTO TUESDAY MORNING. SEAS WILL SHOW THE VARIABILITY OF THE WINDS AS A RESIDUAL RANGE OF 3-5 FEET WILL DROP TO 2-4 FEET EARLY MONDAY INCREASING ONCE AGAIN BY EARLY TUESDAY. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM SATURDAY...THE WIND SHIFT WITH THE FRONT WILL BE THE BIG EVENT FOR THE EXTENDED COASTAL WATERS FORECAST. THE FRONT SHOULD CROSS THE WATERS IN THE AFTERNOON WITH A NORTHERLY FLOW IN PLACE BY 0000 UTC WEDNESDAY. SPEEDS SHOULD BE 15-20 KNOTS. FOR WEDNESDAY THE FLOW WILL VEER MORE TO NORTHEAST AND CONTINUE IN A 15-20 KNOT RANGE PROBABLY EDGING CLOSER TO 15 FOR MOST OF THE AFTERNOON. EXPECT SEAS OF 2-4 FEET. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST SUNDAY FOR AMZ250-252-254- 256. && $$ SYNOPSIS...SHK NEAR TERM...DCH SHORT TERM...SHK LONG TERM...SHK AVIATION...HDL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
353 AM EST SAT DEC 7 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION THIS MORNING. THE FRONT WILL STALL TO THE SOUTH INTO SUNDAY THEN LIFT BACK NORTH THROUGH THE AREA SUNDAY NIGHT. A STRONGER COLD FRONT WILL APPROACH FROM THE WEST MONDAY AND CROSS EARLY TUESDAY. COOL HIGH PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /TODAY/... AS OF 345 AM SATURDAY...PATCHY SHOWERS ARE INDICATED JUST NORTHWEST OF OUR CWA. PER LATEST 3 KM HRRR AND RAP MODELS...BULK OF THE PRECIPITATION WILL START TO ARRIVE IN OUR FAR NORTHWESTERN COUNTIES BETWEEN 10Z AND 12Z. THIS PRECIPITATION WILL OCCUR BEHIND STRONG COLD FRONT WHICH IS JUST NORTH AND WEST OF OUR CWA. THE RAIN WILL OVERSPREAD THE AREA THROUGH THE MORNING AND CONTINUE THROUGH THE DAY AND WILL HAVE LIKELY POPS EVERYWHERE. TEMPERATURES SHOULD REACH THEIR MAXIMUM THIS MORNING THEN SLOWLY FALL THROUGH THE DAY AS THE COLD FRONT WORKS ITS WAY OFFSHORE BY THE AFTERNOON. PER LATEST WATER VAPOR SATELLITE...THIS SYSTEM CONTAINS MOSTLY PACIFIC MOISTURE AND THINK THE QPF TOTAL WILL BE RATHER LIGHT...ON THE ORDER OF ONE QUARTER INCH OF LESS FOR THE MOST PART. GUSTY NORTH WINDS BEHIND THE FRONT WILL MAKE FOR A CHILLY WET AFTERNOON ACROSS EASTERN NORTH CAROLINA FOLLOWING THE NEAR RECORD-WARMTH OF THE PAST TWO DAYS. && .SHORT TERM /TONIGHT/... AS OF 350 AM SATURDAY...A STEADY LIGHT RAIN ACCOMPANIED BY GUSTY NORTH WINDS WILL CONTINUE OVERNIGHT. MINIMUM TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 30S TO LOWER 40S EXCEPT MID TO UPPER 40S ALONG THE OUTER BANKS. WILL KEEP POPS IN THE LIKELY CATEGORY OVER MOST OF THE AREA TONIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 330 AM 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. A STRONG FRONTAL INVERSION WILL BE PRESENT SUN AS WINDS JUST ALOFT REMAIN SW WITH STRONG NLY SURFACE WINDS DUE TO HIGH PRESSURE AT THE SURFACE RIDGING SOUTH OVER THE AREA FROM THE MID-ATLANTIC STATES. THIS WILL PRODUCE WIDESPREAD RAIN AND LOW CLOUDS THROUGH SUN. COOLER TEMPS EXPECTED ON SUN DUE TO CLOUDS/PRECIP WITH HIGHS STRUGGLING IN THE 40S INLAND TO 50S ALONG THE COAST. LATEST GUIDANCE CONTINUES TO INDICATE A COASTAL TROUGH DEVELOPING SUN AFTERNOON...WHICH BECOMES A WEAK LOW THAT MOVES NNE ALONG THE NC COAST SUN NIGHT. AS THE LOW MOVES NE OF THE AREA LATE SUN NIGHT/EARLY MON MORNING...COLD AIR DAMMING SCENARIO WILL SHIFT NW OF THE REGION AS SW RETURN FLOW TAKES OVER WITH EASTERN NC AGAIN IN THE WARM SECTOR. RAIN CHANCES WILL END FROM SOUTH TO NORTH ACROSS E NC LATE SUN...WITH ONLY ISO SHOWERS EXPECTED SUN NIGHT. UPPER RIDGE WILL STRENGTHEN AGAIN MON WITH HIGH TEMPS EXPECTED BACK INTO THE UPPER 60S TO LOWER 70S UNDER PARTLY SUNNY SKIES. LOW LEVEL THICKNESSES BUILD TO THE 1375-1385 METER RANGE...BUT MIXED CLOUDS MAY INHIBIT FULL INSOLATION SO HELD TEMPS IN THE LOW 70S TO UPPER 60S...ALTHOUGH GREATER BREAKS IN CLOUD COVER COULD MEAN TEMPS REACHING A FEW DEGREES HIGHER THAN CURRENTLY FORECAST. ANOTHER COLD FRONT WILL PASS THROUGH EASTERN NC EARLY TUES MORNING MEANING ANOTHER NON-DIURNAL TEMP REGIME EXPECTED WITH HIGHS BEING REALIZED IN THE MORNING WITH TEMPS PLUNGING IN THE AFTERNOON. RAIN EXPECTED ONCE AGAIN WITH THIS FRONTAL BOUNDARY AS PLENTY OF GULF OF MEXICO MOISTURE IN SW FLOW ALOFT. BEST CHANCES WILL BE LATE MON NIGHT ACROSS THE NORTH CWA TRANSITIONING TO THE REST OF THE AREA TUES. MAINTAINED LIKELY POPS DUE TO STRONG AGREEMENT AMONGST OPER MODEL RUNS BETWEEN GFS/ECMWF AND ECMWF ENSEMBLE MEAN. 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 MOISTURE INTO THE EASTERN HALF OF THE CWA...THUS ADDED SLIGHT CHANCE POPS THURS. THE LOW WILL SHIFT WELL OFFSHORE THURS NIGHT WITH A RETURN TO DRY CONDITIONS OVER THE AREA THROUGH FRI...WITH TEMPS STILL 5-8 F BELOW NORMAL FOR MID DECEMBER. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /THROUGH SAT/... AS OF 1 AM SATURDAY...VFR CONDITIONS CURRENTLY AT ALL OF THE TAF SITES WITH PRECIPITATION NOT LIKELY TO ARRIVE UNTIL AFTER 12Z. CEILINGS WILL LOWER TO IFR IN OCCASIONAL RAIN AND SHOULD REMAIN IN THE IFR THROUGH SUNDAY MORNING. N WINDS WILL BE GUSTY AFTER FRONTAL PASSAGE LATER THIS MORNING. LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 330 AM SAT...MODEL SOUNDINGS INDICATE A PROLONGED PERIOD OF MVFR/IFR CONDITIONS THROUGH MUCH OF SUN...WITH WIDESPREAD RAIN. A WEAK LOW OFF THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW TAKING OVER AND PRECIP CHANCES DIMINISHING WITH LOWER CIGS LIFTING N OF THE REGION SUN NIGHT INTO MON...THOUGH FOG MAY BE A POSSIBILITY SUN NIGHT. ANOTHER COLD FRONT CROSS THE TERMINALS FROM NW TO SE TUES WITH ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED CEILINGS/VSBYS THROUGH TUES. HIGH PRESSURE BUILDS OVER THE REGION TUES NIGHT THROUGH MID TO LATE WEEK WITH VFR RETURNING IN MOSTLY SUNNY SKIES. && .MARINE... SHORT TERM /THROUGH SAT/... AS OF 355 AM SATURDAY...SOUTHWEST WINDS ARE SLOWLY INCREASING INTO THE 15 TO 20 KNOT RANGE EARLY THIS MORNING. AS THE COLD FRONT SLOWLY CROSSES THE AREA BY EARLY AFTERNOON...EXPECT NORTHERLY WINDS INCREASING TO 20 TO 25 KNOTS WITH 25 TO 30 KNOTS AT TIME NORTH OF CAPE LOOKOUT. LOCAL NWPS/SWAN MODEL INDICATES SEAS AS HIGH AS 9 TO POSSIBLE 10 FEET LATER TODAY AND TONIGHT WITH THE GUSTY NORTHERLY WINDS. GRADIENT SLACKENS A BIT BY LATE IN THE DAY SUNDAY AS SURFACE LOW MOVES ALONG THE NOW OFFSHORE FRONTAL BOUNDARY. LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 330 AM SAT...SCA CONDITIONS WILL PERSIST OVER THE WATERS THROUGH SUN MORNING AS N SURGE OF 20-25 KT CONTINUES WITH SEAS ELEVATED 5-7 FT. MODELS IN AGREEMENT WITH A WEAK INVERTED/COASTAL TROUGH OVER THE SOUTHERN/CENTRAL WATERS SUN AFTERNOON WHICH DEVELOPS INTO A WEAK SURFACE LOW AND MOVES NNE ALONG THE NC COAST SUN NIGHT. SURFACE WINDS WILL BECOME SW ONCE THE WEAK LOW LIFTS NORTH OF THE WATERS SUN NIGHT. WINDS AND SEAS SUBSIDE BELOW SCA CRITERIA MON MORNING INTO TUES WITH SW WINDS 10-15 KT AND SEAS 3-5 FT. WINDS SHIFT NW/N AND INCREASE 15-20 KT DUE TO POST-FRONTAL CAA SURGE ASSOCIATED WITH STRONG HIGH PRESSURE BUILDING OVER THE WATERS TUES NIGHT INTO WED. SEAS BUILD 4-7 FT LATE TUES/TUES NIGHT. HIGH PRESSURE BUILDS SE OVER THE WATERS WED WITH SEAS SUBSIDING BELOW 6 FT ALTHOUGH MAY SEE HIGHER SEAS LINGER FOR THE CENTRAL WATERS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR AMZ135. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 6 PM EST THIS EVENING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR AMZ150-152-154. SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR AMZ156-158. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...DAG AVIATION...CTC/DAG MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
103 AM EST SAT DEC 7 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT AND CROSS THE REGION SATURDAY MORNING. THE FRONT WILL STALL TO THE SOUTH INTO SUNDAY THEN LIFT BACK NORTH THROUGH THE AREA SUNDAY NIGHT. A STRONGER COLD FRONT WILL APPROACH FROM THE WEST MONDAY AND CROSS EARLY TUESDAY. HIGH PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1255 AM SATURDAY...THE 3 KM HRRR AND RAP MODELS SHOW THE BULK OF THE PRECIPITATION WILL NOT ARRIVE IN THE MHX CWA UNTIL AFTER 10Z AND MOSTLY AFTER 12Z. HAVE DROPPED POPS OVER THE NEXT FEW HOURS TO ACCOUNT FOR THIS DELAY. ANOTHER MILD NIGHT WITH TEMPS IN THE 65 TO 70 DEGREE RANGE. TEMPERATURES SHOULD REMAIN FAIRLY STEADY OVER THE NEXT FEW HOURS. COLD FRONT CURRENTLY IN THE WESTERN PIEDMONT AND WILL ARRIVE IN OUR AREA BY DAYBREAK. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... AS OF 215 PM FRIDAY...COLD FRONT OVER NRN TIER EARLY WILL PUSH S THRU THE REGION SATURDAY MORN. TEMPS WILL NOT FOLLOW TYPICAL DIURNAL CURVE WITH HIGHS EARLY IN THE DAY WITH TEMPS LOWERING WITH STRONG CAA IN WAKE OF FRONT. BY LATE AFTN TEMPS WILL BE IN THE 40S N TO LOWER 50S FAR S. MDLS SIMILAR IN SHOWING DEEP MOISTURE MAINLY WITH AND BEHIND COLD FRONT AND EXPECT WIDESPREAD RAIN WITH LIKELY TO CATEGORICAL POPS. RAINFALL WILL NOT BE OVERLY HEAVY WITH AROUND 1/4 INCH MOST SPOTS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... AS OF 330 PM FRI...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. A STRONG FRONTAL INVERSION WILL BE PRESENT SAT NIGHT THROUGH SUN AS WINDS JUST ALOFT REMAIN SW WITH STRONG NLY SURFACE WINDS. THIS WILL PRODUCE WIDESPREAD RAIN AND LOW CLOUDS THROUGH SUNDAY. COOLER TEMPS EXPECTED ON SUNDAY DUE TO CLOUDS/PRECIP WITH HIGHS STRUGGLING IN THE 40S INLAND TO 50S ALONG THE COAST. LATEST GUIDANCE CONTINUES TO INDICATE A COASTAL TROUGH DEVELOPING SUN AFTERNOON...WHICH BECOMES A WEAK LOW THAT MOVES NNE ALONG THE NC COAST SUN NIGHT. AS THE LOW MOVES NE OF THE AREA LATE SUN NIGHT/EARLY MON MORNING...COLD AIR DAMMING SCENARIO WILL SHIFT NW OF THE REGION AS SW RETURN FLOW TAKES OVER WITH EASTERN NC AGAIN IN THE WARM SECTOR. RAIN CHANCES WILL END FROM SOUTH TO NORTH ACROSS E NC LATE SUN...WITH ONLY ISO SHOWERS EXPECTED BY SUN NIGHT. UPPER RIDGE WILL STRENGTHEN AGAIN MON WITH HIGH TEMPS EXPECTED BACK INTO THE UPR 60S TO LOWER 70S UNDER PARTLY SUNNY SKIES. LOW LEVEL THICKNESSES BUILD TO THE 1380 METER RANGE...BUT MIXED CLOUDS MAY INHIBIT FULL INSOLATION SO HELD TEMPS IN THE LOW 70S TO UPPER 60S...ALTHOUGH GREATER BREAKS IN CLOUD COVER COULD MEAN TEMPS REACHING A FEW DEGREES HIGHER THAN CURRENTLY FORECAST. ANOTHER COLD FRONT WILL PASS THROUGH EASTERN NC EARLY TUES MORNING...MEANING ANOTHER NON-DIURNAL TEMP REGIME EXPECTED WITH HIGHS BEING REALIZED IN THE MORNING WITH TEMPS PLUNGING IN THE AFTERNOON. RAIN EXPECTED ONCE AGAIN WITH THIS FRONTAL BOUNDARY AS PLENTY OF GOM MOISTURE WILL BE PRESENT WITH THE STRONG FORCING EXPECTED. BEST CHANCES WILL BE LATE MON NIGHT ACROSS THE NORTH TRANSITIONING TO THE REST OF THE FA TUE. HAVE INC POPS TO LIKELY DUE TO STRONG AGREEMENT AMONGST OPERATIONAL RUNS BETWEEN GFS/ECM AND ECM ENSEMBLE MEAN. RAIN WILL QUICKLY END BY TUE EVENING AS THE FRONT SWEEPS OFFSHORE. MUCH COOLER/DRIER AIR WILL FILTER IN BEHIND THE FRONT WITH HIGHS IN THE UPPER 40S/LOW 50S WED/THUR WITH LOWS BELOW FREEZING MOST AREAS INLAND. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /THROUGH SAT/... AS OF 1 AM SATURDAY...MVFR CEILINGS LIMITED TO KOAJ WITH VFR ELSEWHERE CURRENTLY. PRECIPITATION NOT LIKELY TO ARRIVE UNTIL AFTER 12Z. CEILINGS WILL LOWER TO IFR IN OCCASIONAL RAIN AND SHOULD REMAIN IN THE IFR THROUGH SUNDAY MORNING. N WINDS WILL BE GUSTY AFTER FRONTAL PASSAGE LATER THIS MORNING. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 330 PM FRI...MODEL SOUNDINGS INDICATE A PROLONGED PERIOD OF MVFR/IFR CONDITIONS THROUGH MUCH OF SUNDAY...WITH WIDESPREAD RAIN CONTINUING THROUGH SUN. A WEAK LOW OFF THE COAST WILL PUSH NE THROUGH THE AREA SUN NIGHT WITH SW FLOW TAKING OVER AND PRECIP CHANCES DIMINISHING WITH LOWER CIGS LIFTING N OF THE REGION...THOUGH FOG MAY BE A POSSIBILITY SUN NIGHT. ANOTHER COLD FRONT CROSS THE TERMINALS FROM NW TO SE TUES WITH ANOTHER ROUND OF MVFR/IFR CONDITIONS POSSIBLE IN LOWERED CEILINGS/VSBYS THROUGH TUES. HIGH PRESSURE BUILDS OVER THE REGION TUES NIGHT THROUGH MID TO LATE WEEK WITH VFR RETURNING IN MO SUNNY SKIES. && .MARINE... SHORT TERM /THROUGH SAT/... AS OF 1 AM SATURDAY...WINDS WILL CONTINUE TO SLOWLY INCREASE AHEAD OF A STRONG COLD CURRENTLY OVER THE WESTERN PIEDMONT. SW WINDS ARE CURRENTLY 15 TO 20 KNOTS OVER THE CENTRAL AND NORTHERN COASTAL WATERS. SEAS CURRENTLY RANGE FROM 2 TO 4 FEET...BUT THE BUOY 30 MILES SE OF NEW RIVER HAS INCREASED TO 6 FEET AND EXPECT SEAS TO GRADUALLY INCREASE TOWARD MORNING. AS NRLY WINDS INCREASE SAT SEAS TO 8 FT OR SO EXPECTED OUTER CNTRL AND NRN WTRS BY AFTN. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AS OF 330 PM FRI...SCA CONDITIONS WILL PERSIST OVER THE WATERS THROUGH THE WEEKEND AS N SURGE OF 20-25 KT CONTINUES THROUGH SUN MORNING. SEAS SHOULD MAX OUT AT 6 TO 8 FT ACROSS THE NORTHERN WATERS SAT NIGHT INTO SUN MORNING. MODELS IN AGREEMENT WITH A WEAK INVERTED/COASTAL TROUGH OVER THE SOUTHERN/CENTRAL WATERS SUN AFTERNOON WHICH DEVELOPS INTO A WEAK SURFACE LOW AND MOVES NNE ALONG THE NC COAST SUN NIGHT. SURFACE WINDS WILL BECOME SW ONCE THE WEAK LOW LIFTS NORTH OF THE WATERS SUN NIGHT. WINDS AND SEAS BRIEFLY SUBSIDE BELOW SCA CRITERIA MON MORNING WITH SW WINDS 10-15 KT AND SEAS 3-5 FT...THEN INCREASE TO 15-20 KT AND SEAS 4-7 FT MON NIGHT AS THE GRADIENT TIGHTENS BETWEEN SURFACE RIDGE OFF THE SOUTHEASTERN COAST AND A COLD FRONT APPROACHING FROM THE NW. COLD FRONT WILL PASS THROUGH THE WATERS TUE WITH WINDS TURNING SHARPLY NORTHERLY WITH SPEEDS 15 TO 20 KT WITH HIGHER GUSTS. SEAS WILL BUILD TO 5 TO 7 FEET WITH THE STRONG CAA. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST SUNDAY FOR AMZ135. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 6 PM EST THIS EVENING FOR AMZ130. SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR AMZ150-152-154. SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR AMZ156-158. && $$ SYNOPSIS...RF NEAR TERM...CTC SHORT TERM...RF LONG TERM...TL AVIATION...JAC/CTC/TL MARINE...CTC/TL/LEP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1153 PM CST FRI DEC 6 2013 .UPDATE... ISSUED AT 1153 PM CST FRI DEC 6 2013 EXPANDED THE WIND CHILL WARNING TO INCLUDE THE SOUTHWEST WHICH WAS PREVIOUSLY IN A WIND CHILL ADVISORY. 05-06 UTC OBSERVATIONS INDICATE WIND CHILLS TO 45 BELOW ARE OCCURRING ACROSS THE SOUTHWEST...AND ARE FORECAST TO CONTINUE INTO SATURDAY MORNING. UPDATE ISSUED AT 944 PM CST FRI DEC 6 2013 UPDATE FOR TEMPERATURE TRENDS AND SKY COVER. A BATCH OF STRATUS HAS EXPANDED AND DRIFTED SOUTH INTO NORTHERN NORTH DAKOTA. THIS AREA IS MODELED WELL BY THE 13KM RAP AND PERSISTS OVERNIGHT BEFORE SCATTERING OUT SATURDAY MORNING. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 239 PM CST FRI DEC 6 2013 ARCTIC AIR FIRMLY IN PLACE TODAY THROUGH SATURDAY AS TEMPERATURES REMAIN BELOW ZERO ACROSS THE WEST AND CENTRAL. DIMINISHED WINDS DEEP SNOW COVER AND AND THE CENTER OF THE ARCTIC HIGH MOVING THROUGH SOUTHWEST NORTH DAKOTA TONIGHT SHOULD ALLOW OVERNIGHT LOWS TO FALL INTO THE 20S BELOW ZERO. EVEN A MODEST AMOUNT OF WIND WILL RESULT IN WIND CHILLS COLDER THAN 40 BELOW ACROSS THE NORTH C=SOUTH CENTRAL AND EAST. ISSUED A WIND CHILL WARNING MAINLY ALONG AND NORTH AND EAST OF LAKE SAKAKAWEA AND THE MISSOURI RIVER VALLEY. SOME CLOUDS...AND LIGHTER WINDS ACROSS THE SOUTHWEST SHOULD HOLD THE WIND CHILLS IN THE ADVISORY CATEGORY. THERE WILL PROBABLY BE FURTHER ADVISORIES SATURDAY NIGHT INTO SUNDAY...ESPECIALLY NORTH. WILL CONCENTRATE TO ION THE MOST HAZARDOUS ASPECTS OF THE ARCTIC AIR TONIGHT AND SATURDAY FIRST. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 239 PM CST FRI DEC 6 2013 THE LONG TERM BEGINS WITH A BRIEF PHASING OF THE NORTHERN/SOUTHERN STREAMS SUNDAY...FOLLOWED BY THE NORTHERN STREAM TAKING FIRM CONTROL AGAIN MONDAY THROUGH WEDNESDAY. FOR THURSDAY AND FRIDAY...A NEAR ZONAL FLOW IS EXPECTED AS THE COLDEST OF THE ARCTIC AIR RETREATS NORTH. FOR SATURDAY NIGHT AND SUNDAY...CLOUDS WILL THICKEN AND LOWER ACROSS THE SOUTH SATURDAY NIGHT WITH LIGHT SNOW FORECAST TO DEVELOP ALONG AN INVERTED SURFACE TROUGH WHICH EXTENDS FROM COLORADO INTO SOUTHERN NORTH DAKOTA. QPF AMOUNTS REMAIN LIGHT WITH A COUPLE HUNDREDTHS. WITH SNOW RATIOS AT 20 TO 1...EXPECT THE POTENTIAL FOR AROUND A HALF INCH OF SNOW...ALONG AND SOUTH OF INTERSTATE 94 THROUGH SUNDAY AFTERNOON. THE NORTH WILL REMAIN DRY BUT VERY COLD. EXPECTING A WIND CHILL HEADLINE/ADVISORY FOR THE NORTH INTO SUNDAY MORNING. THE CENTRAL AND SOUTH WILL BE UNDER THE INFLUENCE OF CLOUDS AND INCREASING POTENTIAL FOR LIGHT SNOW...THUS WILL NOT SEE WIND CHILL CRITERIA BEING MET CENTRAL AND SOUTH FOR SATURDAY NIGHT INTO SUNDAY MORNING. FOR SUNDAY NIGHT...DRY BUT VERY COLD WITH WIND CHILL VALUES BETWEEN 25 AND 39 BELOW ZERO...WHICH WILL LIKELY NECESSITATE ANOTHER WIND CHILL ADVISORY FOR ALL OF WESTERN AND CENTRAL NORTH DAKOTA. FOR MONDAY INTO MONDAY NIGHT...AN ALBERTA CLIPPER REMAINS POISED TO SWEEP THROUGH MONDAY AFTERNOON INTO MONDAY NIGHT. STRONG H85 WINDS OF 50KT WILL ACCOMPANY THE CLIPPER. HOW MUCH OF THIS MOMENTUM WILL TRANSLATE TO THE SURFACE IS STILL UNKNOWN. GFS SOUNDINGS INDICATE AN ISOTHERMAL LAYER JUST ABOVE THE SURFACE...AND AN ADIABATIC LAPSE RATE IS NOT SEEN UNTIL FARTHER UP IN THE SOUNDING. THUS THERE MAY BE A DISCONNECT WITH LINKING UP TO THESE STRONGEST WINDS. CONCUR WE WILL HAVE WINDS BETWEEN 20 AND 35 MPH WITH GUSTS TO 40 MPH...WHICH WILL PRODUCE BLOWING AND DRIFTING SNOW...BUT NOT READY TO GO WITH ANYTHING MUCH HIGHER THAN THAT AT THIS TIME. HAVE COLLABORATED WITH NEIGHBORING OFFICES AND INCREASED WINDS BUY 5KT OVER THE ALLBLEND. WILL AWAIT FUTURE RUNS BEFORE MAKING ANY OTHER CHANGES. DO EXPECT LIGHT SNOW TO DEVELOP IN THE MORNING ACROSS THE NORTHWEST AND THEN SPREAD SOUTHEAST IN THE AFTERNOON/EVENING. BLOWING/DRIFTING SNOW WILL COMMENCE MONDAY AFTERNOON THROUGH MONDAY NIGHT. A SPECIAL WEATHER STATEMENT OR POSSIBLE WINTER WEATHER ADVISORY MAY BE NEEDED IN THE NEXT DAY OR TWO. THE LIGHT SNOW WILL DIMINISH MONDAY NIGHT. NEW SNOWFALL ACCUMULATIONS SHOULD RANGE FROM A HALF INCH UP TO ONE INCH MONDAY INTO MONDAY NIGHT. IN ADDITION...WE WILL LIKELY NEED WIND CHILL HEADLINES LATE MONDAY NIGHT INTO TUESDAY MORNING FOR THE NORTH AND EXTENDING INTO THE JAMES RIVER VALLEY WITH READINGS BETWEEN 25 AND 35 BELOW ZERO. FOR TUESDAY AND WEDNESDAY...NORTHWEST FLOW ALOFT WITH A 1040MB SURFACE HIGH WILL SLIDE ACROSS NORTH DAKOTA. GENERALLY A DRY AND COLD PATTERN DURING THIS TIME. WIND CHILL TEMPERATURES OF 25 TO 35 BELOW ZERO ARE FORECAST ACROSS THE NORTH...AND INTO THE JAMES RIVER VALLEY. FOR THURSDAY AND FRIDAY...WARM AIR ADVECTION PROCESSES WILL ALLOW FOR THE POTENTIAL OF LIGHT SNOW MAINLY ACROSS THE NORTH AND INTO THE TURTLE MOUNTAINS THURSDAY. HIGH TEMPERATURES THURSDAY WILL RANGE BETWEEN 15 AND 28 DEGREES ABOVE ZERO THURSDAY. HOWEVER THIS WILL BE SHORT LIVED AS ANOTHER SURGE OF COLD AIR ADVECTION FRIDAY...WITH HIGHS FORECAST FROM ZERO TO 15 ABOVE. NORTHWEST FLOW FRIDAY MAY ALLOW ANOTHER SYSTEM TO PRODUCE A CHANCE OF SNOW FRIDAY INTO FRIDAY NIGHT. THE GFS AND ALLBLEND BOTH ADVERTISE THIS...BUT THE ECMWF IS DRY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1153 PM CST FRI DEC 6 2013 AN AREA OF MVFR STRATUS IS DRIFTING SOUTH AND WILL IMPACT KMOT AND POSSIBLY KISN OVERNIGHT. VERY LIGHT SNOW IS POSSIBLE UNDER THIS DECK. OTHERWISE...VFR CONDITIONS AT OTHER TAF SITES THROUGH 06 UTC SATURDAY. LIGHT SNOW POSSIBLE AT KBIS AND KJMS POST 06 UTC. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND CHILL WARNING UNTIL 1 PM CST /NOON MST/ SATURDAY FOR NDZ001>005-009>013-017>023-025-031>037-040>048-050-051. && $$ UPDATE...AYD SHORT TERM...WAA LONG TERM...KS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
844 PM CST SUN DEC 8 2013 .DISCUSSION...02 SURFACE ANALYSIS PLACES A WEAK QUASI-STATIONARY BOUNDARY/SURFACE LOW NEAR THE LOUISIANA/MISSISSIPPI/ALABAMA GULF COAST THIS EVENING. MEANWHILE...A RIDGE OF HIGH PRESSURE IS LOCATED ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY INTO PORTIONS OF THE MID SOUTH. TEMPERATURES AS OF 8 PM CST RANGE FROM THE MIDDLE 30S TO AROUND 40 DEGREES ACROSS WEST TENNESSEE NEAR THE TENNESSEE RIVER AND PORTIONS OF NORTHEAST MISSISSIPPI AND UPPER 20S TO LOWER 30S ALONG AND WEST OF THE MISSISSIPPI RIVER. KNQA/KGWX WSR-88D RADAR TRENDS INDICATE LIGHT RAIN SHOWERS ACROSS NORTHEAST MISSISSIPPI IN ASSOCIATION WITH A MID LEVEL SHORTWAVE TROUGH AND AN UPPER LEVEL JET STREAK MOVING ACROSS THE REGION. LATEST RUC SHORT TERM MODEL SEEMS TO BE HANDLING CURRENT TRENDS THE BEST WITH RESPECT TO PRECIPITATION. WILL MAKE ADJUSTMENTS TO LIMIT AND LOWER PRECIPITATION CHANCES OVERNIGHT TO EXTREME NORTHEAST MISSISSIPPI. AS OF 8 PM CST...VISIBILITIES ARE CURRENTLY RANGING FROM 4SM TO P6SM. LIGHT WINDS HAVE KEPT LOW LEVEL MOISTURE LIFTED AS A LOW STRATUS LAYER THUS FAR. WILL CONTINUE TO MONITOR SHORT TERM TRENDS FOR THE POSSIBLE DEVELOPMENT OF FOG/FREEZING FOG AND ANY HEADLINES IF IT BECOMES NECESSARY. WILL ALSO MAKE MINOR ADJUSTMENTS TO TEMPERATURES AND ALL OTHER ELEMENTS AS NEEDED TO ACCOUNT FOR LATEST TRENDS. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC && .PREV DISCUSSION... /ISSUED 536 PM CST SUN DEC 8 2013/ UPDATE...AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 320 PM CST SUN DEC 8 2013/ A SHARP TEMPERATURE GRADIENT IS OCCURRING ACROSS THE MIDSOUTH THIS EVENING. LOCATIONS SOUTH AND EAST OF A MEMPHIS TO JACKSON TENNESSEE LINE ARE REPORTING TEMPERATURES IN THE MID 30S TO LOWER 40S. NORTH AND WEST OF THIS LINE TEMPERATURES RANGE FROM 28-32 DEGREES. TEMPERATURES ALSO REMAIN NEAR FREEZING FARTHER SOUTH IN THE DELTA SUCH AS MARIANNA...TUNICA AND CLARKSDALE. PATCHY DENSE FREEZING FOG HAS FORMED ALONG THIS GRADIENT BETWEEN THE ARCTIC AIR AND THE WARMER AIR. WEST MEMPHIS...MILLINGTON...BLYTHEVILLE...DYERSBURG AND UNION CITY ARE REPORTING VISIBILITIES FROM A QUARTER MILE TO THREE QUARTERS OF A MILE. THUS FAR NO ICING HAS OCCURRED AS A RESULT OF THE FOG BUT A LITTLE WORRIED THAT THIS MAY CHANGE ONCE THE SUN GOES DOWN. WILL LET EVENING SHIFT MONITOR FOR ANY POTENTIAL ADVISORIES. MEANWHILE...RAIN CONTINUES TO PUSH NORTHWARD INTO NORTH MISSISSIPPI WHERE LOCATIONS ARE ABOVE FREEZING. THIS IS DUE TO A SFC LOW DEVELOPING ALONG A STATIONARY FRONT NEAR THE GULF COAST. MODELS INDICATE THE NORTHERN EXTENT OF THE PRECIPITATION COULD REACH INTO LOCATIONS THIS EVENING THAT ARE SITTING JUST ABOVE OR AT FREEZING CURRENTLY. AS TEMPERATURES DROP THIS EVENING THIS COULD CHANGE RAIN OVER TO FREEZING RAIN...BUT CONFIDENCE IS LOW THUS AGAIN WILL LET EVENING SHIFT MONITOR FOR ANY POTENTIAL ADVISORIES. WILL JUST MENTION A SLIGHT CHANCE OR CHANCE OF FREEZING RAIN IN THE FORECAST AS BEST CHANCES OF PRECIPITATION WILL OCCUR ACROSS NORTHEAST MISSISSIPPI WHERE LOCATIONS WILL REMAIN ABOVE FREEZING. ANOTHER SFC LOW WILL DEVELOP ALONG THE STATIONARY FRONT LOCATED ALONG THE GULF COAST BY MONDAY EVENING. THIS WILL BRING ANOTHER ROUND OF PRECIPITATION THAT WILL SKIRT NORTHEAST MISSISSIPPI. HOWEVER BY MONDAY EVENING...NORTHWEST WINDS WILL HAVE PUSHED ARCTIC AIR FURTHER SOUTH AND EAST THUS PRECIPITATION COULD FALL IN THE FORM OF FREEZING RAIN IF PRECIPITATION MAKES IT AS FAR NORTH AS NORTHEAST MISSISSIPPI. STAY TUNED. IN ADDITION...A SHORTWAVE WILL SWING ACROSS SOUTHERN MISSOURI AND WESTERN KENTUCKY MONDAY NIGHT. THIS COULD BRING A BRIEF SHOT OF LIGHT SNOW ACROSS PORTIONS OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL AND NORTHWEST TENNESSEE. ANY ACCUMULATIONS THAT WOULD OCCUR WOULD BE LESS THAN AN INCH. BY TUESDAY...ARCTIC HIGH PRESSURE SETTLES OVER THE MIDSOUTH. EXPECT DRY CONDITIONS WITH HIGHS RANGING FROM THE LOWER 30S TO LOWER 40S. A REINFORCING SHOT OF ARCTIC AIR WILL MOVE INTO THE AREA ON WEDNESDAY INTO WEDNESDAY NIGHT. LOWS WEDNESDAY NIGHT WILL RANGE FROM THE MID TEENS TO THE MID 20S. BY THURSDAY NIGHT...THE HIGH WILL SHIFT EAST TURNING WINDS AROUND TO THE SOUTH. THE NEXT LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA ON FRIDAY AND WILL BRING CHANCES FOR PRECIPITATION TO THE MIDSOUTH OVER THE NEXT WEEKEND. HOW QUICKLY THE ARCTIC AIR DEPARTS WILL DEPEND ON POSSIBLY PRECIPITATION TYPE FOR PORTIONS OF NEXT WEEKEND. THE 12Z ECMWF IS COLDER THAN THE 12Z GFS. FOR NOW HAVE TRIED TO GO WITH AN IN BETWEEN SOLUTION WHICH WOULD HAVE TEMPERATURES NEAR NORMAL AND WOULD KEEP PRECIPITATION IN THE FORM OF RAIN. KRM && .AVIATION... 00Z TAF CYCLE VIS HAS IMPROVED TO MVFR LEVELS AT ALL SITES BUT CIGS REMAIN IFR. FEEL LIKE THOSE CIGS WILL CONTINUE MOST OF THE NIGHT POSSIBLY EVEN LOWERING TO LIFR LEVELS FOR BRIEF PERIODS OF TIME. INCLUDED TEMPO 1-200 FOOT CIGS ALONG WITH 1SM BR AT TUP MKL AND MEM FOR BRIEF PERIODS THIS EVENING/TONIGHT. SOME MARGINAL IMPROVEMENT TO CIGS IS EXPECTED BY SUNRISE...BUT NOT ABOVE IFR LEVELS UNTIL AFTER SUNRISE. GUIDANCE WANTS TO CONTINUE TO LIFT CIGS THROUGH THE DAY EVEN TO VFR LEVELS...BASED ON EXPERIENCE...FEEL LIKE CLOUDS WILL LINGER LONGER THAN GUIDANCE SUGGESTS...BUT WILL BRING LEVELS TO 5KFT DURING THE AFTERNOON FOR ALL LOCATIONS EXCEPT TUP. MAY ACCOMPANY RAIN AT TUP WILL BE LIGHT...WITH LITTLE TO NO PRECIPITATION ELSEWHERE. WINDS GENERALLY LIGHT OVERNIGHT...LIGHT FROM THE NORTH TOMORROW. JDS && .PRELIMINARY POINT TEMPS/POPS... MEM 28 39 27 38 / 40 10 20 10 MKL 29 38 24 37 / 50 10 20 10 JBR 24 31 24 32 / 10 10 20 10 TUP 36 43 33 42 / 80 30 60 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
922 PM CST SUN DEC 8 2013 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 856 PM CST SUN DEC 8 2013 CANCELLED WINTER WX ADVISORY FOR NORTHWEST PORTION OF FORECAST AREA AS HAVE HAD GENERALLY LESS THAN AN INCH UP THERE WITH VSBYS REMAINING IN THE 3 TO 5 MILES RANGE. EXPECT TO SEE AN INCH OR LESS ADDITONAL ACCUMULATION OVERNIGHT THERE. AREA OF LIGHT SNOW OVER FOX VALLEY LATE THIS EVENING ASSOCIATED WITH SHORTWAVE DISTURBANCE MOVING ACROSS SOUTHEAST WISCONSIN. VSBYS GENERALLY AROUND 2 MILES WITH SNOWFALL RATES A BIT HIGHER ALONG THE LAKESHORE AS LAKE ENHANCEMENT CONTINUES THERE. VSBYS FROM KEWAUNEE TO SOUTHEAST BROWN COUNTY...TO EAST OF OSHKOSH BEWTEEN 1 AND 2 MILES. BACK/WESTERN EDGE OF THIS AREA OF LIGHT SNOW APPROACHING THE FOX VALLEY THUS EXPECT LIGHT SNOW TO TAPER OFF FROM SOUTHWEST TO NORTHEAST OVER THE NEXT FEW HOURS...EXCEPT FOR THE LAKESHORE COUNTIES. UPSTREAM SHORTWAVE MOVING ACROSS IOWA CONTINUED TO LOOK UNIMPRESSIVE AS IT APPROACHES THE FORECAST AREA. DO NOT FEEL THIS FEATURE WILL BE ABLE TO DO MUCH TO FURTHER ENHANCE LIGHT SNOW OVER THE FORECAST AREA AFTER MIDNIGHT. LATEST RUC...NAM AND HRRR ARE ALL SUGGEST WEAK LIFT AND VERY MINIMAL QPF AMOUNTS. WILL KEEP ADVISORY GOING FOR NOW GIVEN LIGHT SNOW STILL FALLING OVER MUCH OF THE FORECAST AREA. MAY TRIM ADDITIONAL COUNTIES TO THE WEST OF THE FOX VALLEY FROM ADVISORY BEFORE MIDNIGHT IF RADAR RETURNS AND OBSERVED VSBYS REMAIN LACKLUSTER. HIGHEST SNOWFALL AMOUNTS HAVE GENERALLY BEEN AROUND 3 INCHES ALONG THE LAKESHORE FROM MANITOWOC TO DOOR COUNTY. ABOUT 2 INCHES AT NWS GREEN BAY AS OF 845 PM. JUST RECEIVED A REPORT OF 1.8 INCHES SO FAR IN EAST GREEN BAY. UPDATE ISSUED AT 644 PM CST SUN DEC 8 2013 SYSTEM AFFECTING THE FORECAST AREA HAS BEEN RATHER DISORGANIZED AND DISJOINTED THUS FAR. SO FAR...SNOWFALL AMOUNTS HAVE BEEN AROUND AN INCH OR SO THROUGH 6 PM. HOWEVER...WATER VAPOR IMAGERY SHOWS SOMEWHAT MORE ROBUST SHORTWAVE DISTURBANCE ENTERING SOUTHWEST WISCONSIN. THIS FEATURE HAS HELPED TO CREATE A SOMEWHAT MORE SOLID AND ORGANIZED AREA OF LIGHT SNOW ACROSS SOUTHEAST WISCONSIN WITH VSBYS GENERALLY BETWEEN ABOUT 1 AND 2 MILES. THIS AREA OF LIGHT SNOW CONTINUES TO DRIFT NORTHEAST AND WILL LIKELY CLIP THE SOUTHEAST PORTION OF THE FOX VALLEY GENERALLY SOUTH OF A LINE FROM OSH TO KEWAUNEE OVER THE NEXT FEW HOURS. FURTHER AS ANTICIPATED...AN AREA OF LAKE ENHANCED SNOW CONTINUES TO DEVELOP OVER CENTRAL LAKE MICHIGAN AND IS DRIFTING NORTHWEST. RADAR REFLECTIVITIES HAVE BEEN GRADUALLY INCREASING AND EXPNADING IN AREA COVERAGE OVER THE LAST HOUR. APPEARS ACTIVITY AHEAD OF APPROACHING SHORTWAVE ENTERING SOUTHWEST WISCONSIN CONTRIBUTING TO LES ENHANCEMENT OVER CENTRAL LAKE MICHIGAN VIA SEEDER-FEEDER MECHANISM. THUS...EXPECT TO SEE SOMEWHAT HIGHER SNOWFALL RATES ACROSS THE FOX VALLEY THIS EVENING IN ASSOCIATION WITH SHORTWAVE MOVING ACROSS SOUTHEAST WISCONSIN AND LAKE ENHANCEMENT OFF LAKE MICHIGAN. COULD SEE ANOTHER INCH OR PERHAPS TWO MY MIDNIGHT ESPECIALLY SOUTHEAST OFF A LINE FROM STURGEON BAY TO GREEN BAY TO OSHKOSH. LOOKING FURTHER UPSTREAM...PRIMARY SHORTWAVE DISTURBANCE NOW ENTERING NORTHWEST IOWA. THIS FEATURE IS ALSO FORECAST TO MOVE ACROSS THE SOUTHERN WISCONSIN AFTER MIDNIGHT AND MAY HELP TO KEEP SOME LIGHT SNOW GOING AFTER MIDNIGHT ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA. HOWEVER...LOOKING AT SURFACE OBSERVATIONS OVER IOWA...VSBYS NOT VERY LOW AND WERE IN THE 2 TO 4 MILE RANGE. IN FACT THE LATEST HRRR AND RUC FORECASTS SEEM TO SIGNIFICANTLY DISSOLVE THE AREA OF QPF AS THIS FEATURE APPROACHES WISCONSIN. FORCING ACROSS THE NORTHWEST THIRD OF THE FORECAST AREA NOT EXPECTED TO BE VERY STRONG AND THUS FAR SNOWFALL RATES UP THERE HAVE BEEN QUITE LIGHT WITH VSBYS GENERALLY IN THE 2 TO 4 MILE RANGE. WILL SEE HOW THE SHORTWAVE MOVING OUT OF IOWA EVOLVES LATER THIS EVENING...BUT IF CURRENT TRENDS CONTINUE MAY NEED TO CANCEL ADVISORY UP THERE. FOR NOW WILL KEEP ADVISORY GOING OVER ENTIRE FORECAST AREA AND WILL REVIST A BIT LATER THIS EVENING. BOTTOM LINE IS IT APPEARS MOST SIGNIFICANT SNOWFALL WILL BE FOCUSED OVER THE FOX VALLEY AND LAKESHORE. APPEARS FINAL SNOWFALL TOTALS WILL BE ON THE LOW END OF CURRENT FORECAST. && .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 00Z TAF ISSUANCE ISSUED AT 608 PM CST SUN DEC 8 2013 WEAK LOW PRESSURE WILL MOVE NORTHEAST ACROSS SOUTHERN WISCONSIN INTO LOWER MICHIGAN OVERNIGHT BRINGING LIGHT SNOW TO THE AREA. SYSTEM OVERALL IS SOMEWHAT DISJOINTED AND DISORGANIZED THUS SNOWFALL RATES NOT VERY IMPRESSIVE SO FAR THIS EVENING. MAINLY MVFR CIGS AND VSBYS CAN BE EXPECTED THROUGH 06Z AT CENTRAL AND NORTHERN WISCONSIN TAFS SITES. SOMEWHAT STRONGER UPPER-LEVEL FORCING OVER SOUTHEAST WISCONSIN HAS HELPED TO GENERATE SOMEWHAT MORE ORGANIZED AREA OF LIGHT SNOW THERE WHERE IFR CIGS AND VSBYS ARE MORE WIDESPREAD. EXPECT THIS AREA OF IFR CIGS AND VSBYS IN LIGHT SNOW TO DRIFT NORTHEAST TO OSH AND ATW TAF SITES AFTER ABOUT 02Z. LAKE ENHANCED SNOW BANDS OFF OF LAKE MICHIGAN WILL ALSO DRIFT NORTHWESTWARD AND AFFECT LAKESHORE COUNTIES DURING THE EVENING RESULTING IN IFR CIGS AND VSBYS FROM TIME TO TIME...WHICH COULD ALSO AFFECT THE GRB TAF SITE THROUGH ABOUT 08Z. AS SYSTEM MOVES EAST INTO LAKE MICHIGAN AFTER MIDNIGHT...LIGHT SNOW SHOULD BEGIN TO DIMINISH...BUT CIGS SHOULD GENERALLY REMAIN IN THE IFR CATEGORY...ESPECIALLY AT GRB...ATW AND OSH TAF SITES. WESTERLY WINDS WILL DEVELOP BEHIND THE SYSTEM AND BECOME GUSTY BY MORNING LATE MORNING MONDAY. THE GUSTY WEST WINDS WILL LIKELY CREATE SOME BLOWING AND DRIFTING OF THE NEW SNOW PARTICULARLY OVER THE FOX VALLEY. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ013-020>022- 030-031-035>040-045-048>050-073-074. && $$ UPDATE.........ESB SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
917 PM CST SUN DEC 8 2013 .UPDATE... THE SNOW IS FINALLY WINDING DOWN AS THE MAIN WARM ADVECTION PUSHES OFF TO THE EAST. THERE IS ANOTHER AREA OF SNOW SHOWING UP ON RADAR ACROSS IOWA...BUT THE HRRR TAKES THIS MAINLY NORTH OF THE CWA. NOT SURE ABOUT THAT GIVEN THE RADAR MOVEMENT. FORTUNATELY...THIS STUFF ISN/T VERY HEAVY. IT/S WITH THE MAIN SHORT WAVE PUSHING THROUGH. GIVEN THAT IT LOOKS LIKE THE LIGHT SNOW WILL CONTINUE FOR THE NEXT 3 MAYBE 4 HOURS...WILL NOT DO MUCH WITH THE ADVISORY AT THIS POINT. ROADS ARE STILL IN BAD SHAPE...SO THERE/S THAT TO DEAL WITH. WINDS WILL SHIFT TO THE SOUTHWEST THEN WEST SHORTLY AFTER MIDNIGHT...BUT NOT REALLY GET CRANKED UP UNTIL ABOUT 9 OR 10 AM MONDAY MORNING. SO THE MORNING COMMUTE MAY BE SPARED FROM THE WORST DRIFTING DUE TO THE WIND. && .AVIATION/06Z TAFS/... LOOK FOR GRADUALLY IMPROVING CONDITIONS THROUGH THE OVERNIGHT HOURS. STILL EXPECT LIGHT SNOW TO CONTINUE THROUGH ABOUT 1 AM TONIGHT. WINDS WILL BE RATHER LIGHT AND VARIABLE...UNTIL THEY SHIFT AROUND TO THE SOUTHWEST BY ABOUT 1 AM...THEN WEST BY 4 AM. THE STRONGEST WINDS WILL HOLD OFF UNTIL LATER MONDAY MORNING. ANY LINGER IFR CIGS/VSBYS WILL IMPROVE TO MVFR CONDITIONS THROUGH THE EVENING. SKIES WILL EVENTUALLY SCATTER OUT MONDAY AFTERNOON. && .PREV DISCUSSION... /ISSUED 330 PM CST SUN DEC 8 2013/ TONIGHT AND MONDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH. LIGHT TO MODERATE SNOW OCCURRING ACROSS THE AREA...AS FOCUSED LOW LEVEL WARM AIR ADVECTION SHIFTS INTO THE AREA. GOOD BAND OF MODERATE SNOW EXTENDING FROM CENTRAL AND EASTERN IOWA INTO NORTHERN ILLINOIS...AND THIS SHOULD CONTINUE TO SHIFT NORTHEAST INTO THE AREA OVER THE NEXT FEW HOURS. GOOD UPWARD VERTICAL MOTION IN DENDRITE SNOW GROWTH ZONE EXPECTED THROUGH THE EVENING...AS POTENT 500MB VORTICITY MAXIMUM MOVES NORTHEAST THROUGH THE AREA. BUMPED UP SNOWFALL AMOUNTS A BIT...MAINLY IN THE FAR EAST WHERE THE STRONG LAKE EFFECT SNOW BAND MOVED THROUGH EARLIER TODAY. GOING WITH A 3 TO 5 INCH RANGE ACROSS MOST OF THE AREA...WITH A 4 TO 6 INCHES IN THE FAR EASTERN COUNTIES. AMOUNTS AROUND 6 INCHES ARE POSSIBLE ACROSS THE FAR NORTHEAST COUNTIES...WHERE LAKE ENHANCEMENT IS EXPECTED THROUGH THE EVENING. KEPT WINTER WEATHER ADVISORY GOING FOR THE AREA THROUGH 12Z MONDAY. MAY BE ABLE TO CANCEL THE SOUTHWESTERN COUNTIES EARLY...IF SNOW ENDS SOONER THAN EXPECTED THERE. GUSTY WEST WINDS WILL DEVELOP LATE TONIGHT INTO MONDAY...AND CAUSE SOME BLOWING AND DRIFTING SNOW. THIS MAY HAVE AN IMPACT ON THE MONDAY MORNING COMMUTE...ESPECIALLY ON NORTH TO SOUTH ROADS. LATER SHIFTS WILL HAVE TO CONSIDER IF A HEADLINE WILL BE NEEDED FOR THE MORNING COMMUTE. TEMPERATURES WILL NOT RISE MUCH MONDAY...WITH COLD AIR ADVECTION OCCURRING. TEMPERATURES IN THE TEENS ARE EXPECTED...WITH WIND CHILLS IN THE SINGLE DIGITS ABOVE ZERO. MONDAY NIGHT AND TUESDAY - CONFIDENCE...MEDIUM POTENT SHORTWAVE ARRIVES FROM THE NORTHWEST. DIFFERENTIAL CYCLONIC VORTICITY ADVECTION ARRIVES LATE MONDAY NIGHT AND THEN SHIFTS QUICKLY EAST ON TUESDAY MORNING. GFS MORE ROBUST ON THE QPF FIELD INTO THE NORTHERN CWA WHILE THE ECMWF AND NAM ARE FURTHER NORTH. WITH THE LEADING WAA MOISTENING THINGS UP A BIT MONDAY NIGHT WILL HAVE FLURRIES IN THE NW CWA AND THEN PUT A SMALL POP INTO THE NORTHERN CWA ON TUESDAY AS UPPER DYNAMICS AND LOW LEVEL FRONT MOVE THROUGH. LITTLE IF ANY SNOW ACCUM IN THE NORTHERN CWA. TUESDAY NIGHT AND WEDNESDAY - CONFIDENCE...MEDIUM ANOTHER SHORTWAVE DIVES IN ON THE PERSISTENT NORTHWEST FLOW. IN THIS CASE THE FORCING IS SKEWED A BIT FURTHER SOUTH SO WILL HAVE AREA WIDE POPS. RENEWED COLD FRONT AND FRONTAL FORCING ARRIVES WEDNESDAY MORNING. NAM/GFS/GEM HAS PRECIP CONFINED TO THE SOUTHERN CWA WHILE THE ECMWF SUGGESTS A MORE CWA WIDE COVERAGE OF PRECIP. WILL KEEP SNOW AMOUNTS WITH THIS QUICK HITTER UNDER AN INCH. WEDNESDAY NIGHT THROUGH FRIDAY - CONFIDENCE...MEDIUM THIS IS LOOKING TO BE A DRY PERIOD. DIFFERENCES IN THE MODELS ARISE WITH REGARDS TO TEMPS. GFS QUICKLY RETURNS WAA WHILE THE ECMWF HANGS ONTO THE COLD. WILL FOLLOW THE LATTER AT THIS POINT...KEEPING 925 TEMPS IN THE NEGATIVE TEENS CELSIUS. FRIDAY NIGHT AND SATURDAY - CONFIDENCE...LOW WHILE THE UPPER FLOW REMAINS LARGELY NORTHWEST...THE GFS AND GEM IMPLY SOME PHASING OF SOME SOUTHERN AND NORTHERN STREAM ENERGY WHILE THE ECMWF KEEPS THE DOMINANT WAVE WELL SOUTH AND KEEPS US DRY. FOLLOWED ALLBLEND POPS FOR NOW WHICH HAS SOME SMALL CHANCES. SUNDAY - CONFIDENCE...LOW THE GFS KEEPS SOME PRECIP LINGERING WHILE THE ECMWF SHIFTS THE COLD HIGH EAST OF WI WITH MODIFICATION IN THE 925 TEMPS. AVIATION/00Z TAFS/...THE LIGHT TO MODERATE SNOW WILL CONTINUE ACROSS TAF SITES THROUGH MOST OF THE EVENING...BEFORE QUICKLY TAPERING OFF AROUND OR SOON AFTER MIDNIGHT FROM SOUTHWEST TO NORTHEAST. RATES OF 1/4 TO 1/2 INCH PER HOUR ARE EXPECTED...WITH THE BEST RATES OCCURRING THROUGH 03Z MONDAY. TOTAL ACCUMULATIONS OF 3 TO 4 INCHES ARE EXPECTED AT MADISON AND WAUKESHA...TO 4 TO 6 INCH AMOUNTS AT MILWAUKEE AND KENOSHA. CEILINGS NEAR ALTERNATE MINIMUMS...AND VISIBILITIES BELOW...ARE EXPECTED THROUGH THE EVENING. CEILINGS WILL REMAIN MVFR LATER TONIGHT INTO MONDAY. EAST WINDS WILL WEAKEN THIS EVENING AS THE LOW MOVES THROUGH THE AREA. GUSTY WEST WINDS BY 12Z MONDAY ARE EXPECTED...AND LINGER THROUGH THE DAY. THIS WILL CAUSE SOME BLOWING AND DRIFTING SNOW...ESPECIALLY ON NORTH TO SOUTH RUNWAYS. MARINE...SMALL CRAFT ADVISORY IS IN EFFECT UNTIL 03Z MONDAY...AS GUSTY WINDS AND HIGH WAVES LINGER. THERE WILL BE A LULL IN THE WINDS LATER THIS EVENING INTO THE OVERNIGHT HOURS...WITH THE LOW MOVING THROUGH THE AREA. WAVES SHOULD REMAIN BELOW THE 4 FOOT LEVEL. GUSTY WEST WINDS WILL THEN OCCUR MONDAY AND MONDAY EVENING WITH A TIGHT PRESSURE GRADIENT. HIGH WAVES SHOULD LINGER MAINLY OVER THE OPEN WATERS WITH THE OFFSHORE FLOW. FREEZING SPRAY IS POSSIBLE IN THIS AREA. MAY NEED MORE SMALL CRAFT ADVISORIES OR GALE WATCHES/WARNINGS FOR TUESDAY INTO WEDNESDAY...WITH GUSTY OFFSHORE WINDS WITHIN A TIGHT PRESSURE GRADIENT. HIGH WAVES WILL BE TOWARD AND OVER THE OPEN WATERS. FREEZING SPRAY IS POSSIBLE AS WELL IN THIS AREA. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ046-047-051- 052-056>060-062>072. LM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR LMZ643>646. SMALL CRAFT ADVISORY FROM 6 AM TO 10 PM CST MONDAY FOR LMZ643>646. && $$ UPDATE...DAVIS TONIGHT/MONDAY AND AVIATION/MARINE...WOOD MONDAY NIGHT THROUGH SUNDAY...COLLAR
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
718 PM CST SUN DEC 8 2013 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 644 PM CST SUN DEC 8 2013 SYSTEM AFFECTING THE FORECAST AREA HAS BEEN RATHER DISORGANIZED AND DISJOINTED THUS FAR. SO FAR...SNOWFALL AMOUNTS HAVE BEEN AROUND AN INCH OR SO THROUGH 6 PM. HOWEVER...WATER VAPOR IMAGERY SHOWS SOMEWHAT MORE ROBUST SHORTWAVE DISTURBANCE ENTERING SOUTHWEST WISCONSIN. THIS FEATURE HAS HELPED TO CREATE A SOMEWHAT MORE SOLID AND ORGANIZED AREA OF LIGHT SNOW ACROSS SOUTHEAST WISCONSIN WITH VSBYS GENERALLY BETWEEN ABOUT 1 AND 2 MILES. THIS AREA OF LIGHT SNOW CONTINUES TO DRIFT NORTHEAST AND WILL LIKELY CLIP THE SOUTHEAST PORTION OF THE FOX VALLEY GENERALLY SOUTH OF A LINE FROM OSH TO KEWAUNEE OVER THE NEXT FEW HOURS. FURTHER AS ANTICIPATED...AN AREA OF LAKE ENHANCED SNOW CONTINUES TO DEVELOP OVER CENTRAL LAKE MICHIGAN AND IS DRIFTING NORTHWEST. RADAR REFLECTIVITIES HAVE BEEN GRADUALLY INCREASING AND EXPNADING IN AREA COVERAGE OVER THE LAST HOUR. APPEARS ACTIVITY AHEAD OF APPROACHING SHORTWAVE ENTERING SOUTHWEST WISCONSIN CONTRIBUTING TO LES ENHANCEMENT OVER CENTRAL LAKE MICHIGAN VIA SEEDER-FEEDER MECHANISM. THUS...EXPECT TO SEE SOMEWHAT HIGHER SNOWFALL RATES ACROSS THE FOX VALLEY THIS EVENING IN ASSOCIATION WITH SHORTWAVE MOVING ACROSS SOUTHEAST WISCONSIN AND LAKE ENHANCEMENT OFF LAKE MICHIGAN. COULD SEE ANOTHER INCH OR PERHAPS TWO MY MIDNIGHT ESPECIALLY SOUTHEAST OFF A LINE FROM STURGEON BAY TO GREEN BAY TO OSHKOSH. LOOKING FURTHER UPSTREAM...PRIMARY SHORTWAVE DISTURBANCE NOW ENTERING NORTHWEST IOWA. THIS FEATURE IS ALSO FORECAST TO MOVE ACROSS THE SOUTHERN WISCONSIN AFTER MIDNIGHT AND MAY HELP TO KEEP SOME LIGHT SNOW GOING AFTER MIDNIGHT ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA. HOWEVER...LOOKING AT SURFACE OBSERVATIONS OVER IOWA...VSBYS NOT VERY LOW AND WERE IN THE 2 TO 4 MILE RANGE. IN FACT THE LATEST HRRR AND RUC FORECASTS SEEM TO SIGNIFICANTLY DISSOLVE THE AREA OF QPF AS THIS FEATURE APPROACHES WISCONSIN. FORCING ACROSS THE NORTHWEST THIRD OF THE FORECAST AREA NOT EXPECTED TO BE VERY STRONG AND THUS FAR SNOWFALL RATES UP THERE HAVE BEEN QUITE LIGHT WITH VSBYS GENERALLY IN THE 2 TO 4 MILE RANGE. WILL SEE HOW THE SHORTWAVE MOVING OUT OF IOWA EVOLVES LATER THIS EVENING...BUT IF CURRENT TRENDS CONTINUE MAY NEED TO CANCEL ADVISORY UP THERE. FOR NOW WILL KEEP ADVISORY GOING OVER ENTIRE FORECAST AREA AND WILL REVIST A BIT LATER THIS EVENING. BOTTOM LINE IS IT APPEARS MOST SIGNIFICANT SNOWFALL WILL BE FOCUSED OVER THE FOX VALLEY AND LAKESHORE. APPEARS FINAL SNOWFALL TOTALS WILL BE ON THE LOW END OF CURRENT FORECAST. .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 00Z TAF ISSUANCE ISSUED AT 608 PM CST SUN DEC 8 2013 WEAK LOW PRESSURE WILL MOVE NORTHEAST ACROSS SOUTHERN WISCONSIN INTO LOWER MICHIGAN OVERNIGHT BRINGING LIGHT SNOW TO THE AREA. SYSTEM OVERALL IS SOMEWHAT DISJOINTED AND DISORGANIZED THUS SNOWFALL RATES NOT VERY IMPRESSIVE SO FAR THIS EVENING. MAINLY MVFR CIGS AND VSBYS CAN BE EXPECTED THROUGH 06Z AT CENTRAL AND NORTHERN WISCONSIN TAFS SITES. SOMEWHAT STRONGER UPPER-LEVEL FORCING OVER SOUTHEAST WISCONSIN HAS HELPED TO GENERATE SOMEWHAT MORE ORGANIZED AREA OF LIGHT SNOW THERE WHERE IFR CIGS AND VSBYS ARE MORE WIDESPREAD. EXPECT THIS AREA OF IFR CIGS AND VSBYS IN LIGHT SNOW TO DRIFT NORTHEAST TO OSH AND ATW TAF SITES AFTER ABOUT 02Z. LAKE ENHANCED SNOW BANDS OFF OF LAKE MICHIGAN WILL ALSO DRIFT NORTHWESTWARD AND AFFECT LAKESHORE COUNTIES DURING THE EVENING RESULTING IN IFR CIGS AND VSBYS FROM TIME TO TIME...WHICH COULD ALSO AFFECT THE GRB TAF SITE THROUGH ABOUT 08Z. AS SYSTEM MOVES EAST INTO LAKE MICHIGAN AFTER MIDNIGHT...LIGHT SNOW SHOULD BEGIN TO DIMINISH...BUT CIGS SHOULD GENERALLY REMAIN IN THE IFR CATEGORY...ESPECIALLY AT GRB...ATW AND OSH TAF SITES. WESTERLY WINDS WILL DEVELOP BEHIND THE SYSTEM AND BECOME GUSTY BY MORNING LATE MORNING MONDAY. THE GUSTY WEST WINDS WILL LIKELY CREATE SOME BLOWING AND DRIFTING OF THE NEW SNOW PARTICULARLY OVER THE FOX VALLEY. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ005-010>013- 018>022-030-031-035>040-045-048>050-073-074. && $$ UPDATE.........ESB SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
611 PM CST SUN DEC 8 2013 UPDATED AVIATION PORTION FOR 00Z TAF 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 00Z TAF ISSUANCE ISSUED AT 608 PM CST SUN DEC 8 2013 WEAK LOW PRESSURE WILL MOVE NORTHEAST ACROSS SOUTHERN WISCONSIN INTO LOWER MICHIGAN OVERNIGHT BRINGING LIGHT SNOW TO THE AREA. SYSTEM OVERALL IS SOMEWHAT DISJOINTED AND DISORGANIZED THUS SNOWFALL RATES NOT VERY IMPRESSIVE SO FAR THIS EVENING. MAINLY MVFR CIGS AND VSBYS CAN BE EXPECTED THROUGH 06Z AT CENTRAL AND NORTHERN WISCONSIN TAFS SITES. SOMEWHAT STRONGER UPPER-LEVEL FORCING OVER SOUTHEAST WISCONSIN HAS HELPED TO GENERATE SOMEWHAT MORE ORGANIZED AREA OF LIGHT SNOW THERE WHERE IFR CIGS AND VSBYS ARE MORE WIDESPREAD. EXPECT THIS AREA OF IFR CIGS AND VSBYS IN LIGHT SNOW TO DRIFT NORTHEAST TO OSH AND ATW TAF SITES AFTER ABOUT 02Z. LAKE ENHANCED SNOW BANDS OFF OF LAKE MICHIGAN WILL ALSO DRIFT NORTHWESTWARD AND AFFECT LAKESHORE COUNTIES DURING THE EVENING RESULTING IN IFR CIGS AND VSBYS FROM TIME TO TIME...WHICH COULD ALSO AFFECT THE GRB TAF SITE THROUGH ABOUT 08Z. AS SYSTEM MOVES EAST INTO LAKE MICHIGAN AFTER MIDNIGHT...LIGHT SNOW SHOULD BEGIN TO DIMINISH...BUT CIGS SHOULD GENERALLY REMAIN IN THE IFR CATEGORY...ESPECIALLY AT GRB...ATW AND OSH TAF SITES. WESTERLY WINDS WILL DEVELOP BEHIND THE SYSTEM AND BECOME GUSTY BY MORNING LATE MORNING MONDAY. THE GUSTY WEST WINDS WILL LIKELY CREATE SOME BLOWING AND DRIFTING OF THE NEW SNOW PARTICULARLY OVER THE FOX VALLEY. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ005-010>013- 018>022-030-031-035>040-045-048>050-073-074. && $$ SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
330 PM CST SAT DEC 7 2013 .SHORT TERM... TONIGHT...FORECAST CONFIDENCE IS HIGH HIGH PRESSURE WILL SLIDE EAST ACROSS THE REGION TONIGHT. HIGH CLOUDS WILL STREAM EAST NORTHEASTWARD INTO THE AREA LATER THIS EVENING AND OVERNIGHT. TEMPERATURES MAY DROP QUICKLY THIS EVENING THROUGH THE SINGLE DIGITS ABOVE ZERO...AS WINDS DECOUPLE WITH THE PASSING HIGH. TEMPERATURES SHOULD THEN BECOME STEADY OR SLOWLY RISE LATER TONIGHT...AS THE CLOUDS MOVE INTO THE AREA. LAKE EFFECT SNOW SHOWER BAND SHOULD SET UP NORTH TO SOUTH ON THE EASTERN SIDE OF LAKE MICHIGAN INTO THE SOUTHERN END OF THE LAKE THIS EVENING. HRRR INDICATING THIS BAND SHOULD GRADUALLY SHIFT TO THE WEST NORTHWEST LATER TONIGHT...POSSIBLY TRACKING INTO THE FAR SOUTHEAST COUNTIES NEAR THE LAKE IN THE 09Z TO 12Z SUNDAY PERIOD. ADDED POPS IN THIS AREA FOR THIS POSSIBILITY. MOST OF THE LAKE EFFECT SNOW SHOWERS SHOULD HOLD OFF UNTIL AFTER 12Z SUNDAY. SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH THE MODELS ARE VERY SIMILAR WITH A WEAK BUT DEVELOPING LOW PRESSURE THAT WILL APPROACH FROM THE PLAINS. THE SFC LOW WILL BECOME CLOSED OFF AT 1015 MB NEAR OR EAST OF KMKE BY 06Z MON AND CONTINUE TO DEEPEN AS IT MOVES THROUGH THE NORTHERN GREAT LAKES AND INTO CANADA ON MON. A LARGE SCALE AND FAIRLY IMPRESSIVE LOW TO MID LEVEL WARM ADVECTION PATTERN WITH WILL OVERSPREAD THE REGION ON SUN WITH SNOW INTENSIFYING LATER IN THE AFTERNOON AND EVENING WHEN THE SHORTWAVE TROUGH APPROACHES FROM THE SW. A CONSENSUS OF THE MODELS ON QPF YIELDS QPF TOTALS OF 0.15-0.22. THE DEPTH OF THE DENDRITE ZONE VARIES ON MODELS BUT HAS TRENDED LESS DEEP FROM YESTERDAY. THEREFORE WILL GO WITH A MODEL CONSENSUS OF SNOW RATIOS CLOSE TO 20 TO 1 VERSUS SOMETHING HIGHER. THIS YIELDS 3 TO 4 INCHES WITH THE EXCEPTION OF 2-3 NEAR THE IL BORDER. THERE HAS BEEN A SLIGHT NWD TREND WITH THE SHORTWAVE TROUGH AND QPF...SO LESSER AMOUNTS NEAR THE IL BORDER IS REASONABLE. LAKE ENHANCED SNOWS THEN NEED TO BE ADDED IN FOR OZAUKEE AND SHEBOYGAN COUNTIES GIVEN THE 1000-850 MB SELY FLOW AND LAKE TO 850 MB TEMP DIFFERENCES OF 14-17C. THE LAKE EFFECT SNOW CHARTS SUGGESTS ADDING AT LEAST 3 INCHES SO FORECASTING 4-7 INCHES OF SNOW IN SHEBOYGAN AND NRN OZAUKEE COUNTIES. IF GREATER LAKE ENHANCED SNOW IS EXPECTED A WINTER STORM WARNING MAY BE NEEDED. A WINTER WX ADVISORY IS IN EFFECT FOR ALL OF THE CWA FOR THIS SNOW EVENT. BRISK WESTERLY WINDS AND COLD ADVECTION TO PREVAIL ON MON WITH THE ARCTIC AIRMASS RETURNING AFTER HIGHS IN THE 20S ON SUN. WIND GUSTS TO 25 MPH COMBINED WITH A POWDERY SNOW PACK SHOULD RESULT IN AREAS OF BLOWING AND DRIFTING SNOW THAT WILL LIKELY CAUSE SOME PROBLEMS THROUGHOUT THE DAY FOR TRAVEL. A SHORTWAVE SFC RIDGE WILL MOVE ACROSS SRN WI MON NT WITH RADIATIONAL COOLING AND ARCTIC AIR MAKING FOR ANOTHER VERY COLD NIGHT. SWLY WINDS WILL DEVELOP TOWARD MORNING AS AN ALBERTA CLIPPER MOVES ACROSS THE NORTHERN GREAT LAKES. WILL LIKELY ONLY SEE SCT-BKN CLOUD COVER FROM IT ON TUE WITH THE SNOW REMAINING OVER NRN WI. DESPITE SWLY WINDS...HIGH TEMPS TO ONLY REACH INTO THE TEENS. THE BRISK WINDS HOWEVER WILL MAINTAIN VERY COLD WIND CHILLS FOR MON-TUE. .LONG TERM...WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM. A COUPLE WEAK CLIPPERS WILL BRING ONLY SMALL CHANCES OF LIGHT SNOW OR FLURRIES FOR TUE NT INTO POSSIBLY WED AND AGAIN FOR THU. ARCTIC AIR WILL REMAIN OVER THE AREA INTO THU NT. LOW PRESSURE WILL THEN APPROACH FROM THE NRN PLAINS FOR LATE IN THE WEEK WITH WARM ADVECTION BRINGING MODERATING TEMPS AND CHANCES OF LGT SNOW. && .AVIATION/00Z TAFS/... VFR CONDITIONS ARE EXPECTED TONIGHT ACROSS TAF SITES. WEST NORTHWEST WINDS WILL GRADUALLY WEAKEN AND BECOME LIGHT TO CALM TONIGHT...WITH HIGH CLOUDS MOVING INTO THE AREA BY LATER TONIGHT. A LAKE EFFECT SNOW BAND WILL MOVE NORTHWARD TO KENOSHA AROUND 12Z SUNDAY...AND MILWAUKEE/WAUKESHA BY 15Z SUNDAY. THE LIGHT SNOW SHOWERS WITH THE BAND WILL LINGER FOR A 3 TO 5 HOUR PERIOD THEREAFTER...WITH MVFR/IFR CEILINGS AND VISIBILITIES OF 2 TO 3 MILES. LIGHT ACCUMULATIONS OF UP TO 0.5 INCHES IS POSSIBLE. EAST SOUTHEAST WINDS WILL INCREASE SUNDAY. THE LIGHT TO MODERATE SNOW WITH THE LOW PRESSURE SYSTEM MOVING NORTHEAST THROUGH THE REGION WILL REACH MADISON BY 15Z SUNDAY...AND THE EASTERN SITES BY 18Z SUNDAY. THE SNOW WILL BECOME ALL LIGHT BETWEEN 04Z AND 06Z MONDAY WEST TO EAST ACROSS TAF SITES...THEN ENDING BETWEEN 09Z AND 12Z MONDAY SOUTHWEST TO NORTHEAST. WINDS WILL VEER SOUTHWEST BY 06Z MONDAY...AND WEST BY 12Z MONDAY. WINDS WILL BECOME GUSTY LATE SUNDAY NIGHT INTO MONDAY...WITH SOME BLOWING AND DRIFTING SNOW. CEILINGS/VISIBILITIES AT OR BELOW ALTERNATE MINIMUMS ARE EXPECTED...WITH SOME 1/2 MILE VISIBILITIES POSSIBLE AT TIMES. THE SNOW IS EXPECTED TO BE OF THE LIGHT AND FLUFFY VARIETY. SNOWFALL RATES OF 1/4 TO 1/2 INCH PER HOUR ARE EXPECTED...WITH LOCALLY HIGHER RATES POSSIBLE. TOTAL SNOW ACCUMULATIONS OF 3 TO 4 INCHES ARE EXPECTED...HIGHEST AT MADISON/MILWAUKEE AND LOWEST AT KENOSHA. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM NOON SUNDAY TO 6 AM CST MONDAY FOR WIZ046-047-051-052-056>060-062>072. LM...NONE. && $$ TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD SUNDAY NIGHT THROUGH SATURDAY...GEHRING
AREA FORECAST DISCUSSION
NWS TAUNTON MA
100 AM EST MON DEC 9 2013 .SYNOPSIS... LOW PRESSURE LIFTING NORTH FROM THE MID ATLANTIC WILL BRING MIXED PRECIP LATE TONIGHT INTO 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 6 AM THIS MORNING/... 1 AM UPDATE... AREAS OF LIGHT SNOW AND FREEZING DRIZZLE BREAKING OUT ACROSS SNE. DRY AIR IN THE SNOW GROWTH REGION AND LIGHT PRECIP RESULTING IN AREAS OF FZDZ...BUT EXPECT PRECIP TO BECOME SNOW AS STRONGER OMEGA AND STEADIER PRECIP DEVELOPS. HOWEVER...WARMER AIR ALOFT HAS ALREADY REACHED THE SW CT COAST WITH FZRA NOW AT BDR. THIS WILL BE LIFTING NE SO THE SNOW NEAR THE COAST WILL BE SHORT LIVED...CHANGING TO SLEET/FZRA 08-10Z. LATEST NAM STILL INDICATING POTENTIAL FOR MESOSCALE BANDING MOVING UP ALONG THE S COAST AND CAPE/ISLANDS THROUGH 09Z AS STRONG 850 MB FRONTOGENESIS DEVELOPS WITHIN TIGHTENING THERMAL GRADIENT AND DECENT LIFT IN THE SNOW GROWTH REGION. HOWEVER...THIS IS THE TIME THE WARM NOSE ABOVE 800 MB MOVES IN SO PRECIP WILL LIKELY BE CHANGING TO SLEET/FZRA/RA DURING THIS TIME WHICH WILL LIMIT SNOW ACCUM TO A COATING TO POSSIBLY AN INCH. && .SHORT TERM /2 AM THIS MORNING THROUGH 6 PM TUESDAY/... 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 CHALLENGES 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 /TUESDAY 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. A COATING TO PERHAPS 1 INCH OF SNOW IS POSSIBLE IN A FEW LOCATIONS. THERE ALSO IS A LOW PROBABILITY OF A BIT MORE SNOW THAN THAT 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 /06Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. NEAR-TERM /THROUGH TONIGHT/... HIGH CONFIDENCE IN WIDESPREAD IFR CONDITIONS DEVELOPING AS PRECIP MOVES ACROSS THE REGION. LOWER CONFIDENCE IN TIMING OF PTYPE TRANSITIONS. EXPECT SNOW CHANGING TO SLEET/FZRA FROM SOUTH TO NORTH THIS MORNING AND EVENTUALLY TO PLAIN RAIN IN THE COASTAL PLAIN. INTERIOR TERMINALS WILL LIKELY HAVE TO DEAL WITH AN EXTENDED PERIOD OF FREEZING RAIN/DRIZZLE INTO THE AFTERNOON. MINOR SNOW ACCUM UP TO 2 INCHES POSSIBLE. CONDITIONS EXPECTED TO IMPROVE TO VFR LATER TONIGHT. KBOS TAF...HIGH CONFIDENCE IN MVFR/IFR DEVELOPING. LOW CONFIDENCE IN TIMING OF PTYPE TRANSITIONS. KBDL TAF...HIGH CONFIDENCE IN MVFR/IFR DEVELOPING. LOW CONFIDENCE IN TIMING OF PTYPE TRANSITIONS. 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 UNTIL 10 PM EST THIS EVENING FOR CTZ002. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR CTZ003-004. MA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR MAZ002>004-008>011-026. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MAZ005-012>014-017. NH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR NHZ011-012-015. RI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR RIZ001>004-006. MARINE...SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 10 PM EST THIS EVENING FOR ANZ231>234. SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR ANZ235-237- 254>256. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST TUESDAY FOR ANZ250-251. && $$ SYNOPSIS...FRANK/SIPPRELL NEAR TERM...KJC SHORT TERM...SIPPRELL LONG TERM...FRANK AVIATION...KJC/FRANK MARINE...FRANK/SIPPRELL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1155 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 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1155 PM EST SUN DEC 8 2013 WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS CONTINUING OVERNIGHT. 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 AND THIS WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD. && .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 ADVISORY FROM 7 AM MONDAY TO 7 AM EST TUESDAY 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...UPDATED
NWS NORTH PLATTE NE
1112 PM CST SUN DEC 8 2013 .SYNOPSIS... ISSUED AT 326 PM CST SUN DEC 8 2013 H5 ANALYSIS FROM THIS MORNING HAS A HIGHLY AMPLIFIED PATTERN ACROSS NOAM THIS MORNING WITH A RIDGE EXTENDING INTO THE GULF OF ALASKA. A CLOSED LOW WAS OVER WESTERN PORTIONS OF THE HUDSON BAY WITH A DEEP TROUGH OF LOW PRESSURE EXTENDING SSWD INTO THE ROCKIES AND SWRN US. NUMEROUS EMBEDDED SHORTWAVES WERE NOTED ACROSS THE WESTERN CONUS THIS MORNING. THE FIRST OVER SWRN WYOMING...WHICH IS CROSSING CENTRAL COLORADO AND IS EMERGING ONTO THE FRONT RANGES JUST SOUTH OF DENVER...PER SATELLITE AND RADAR IMAGERY. ANOTHER SHORTWAVE WAS LOCATED OVER SWRN SASKATCHEWAN AND SRN ALBERTA...AND A THIRD WAS NOTED OFF THE NRN CALIFORNIA COAST. AT THE SURFACE...AN AREA OF SNOW IN ASSOCIATION WITH THE FIRST SHORTWAVE...EXTENDED FROM AROUND LIMON COLORADO...NEWD TO FAR SOUTHWESTERN NEBRASKA. THE HEAVIEST SNOW PER RADAR IMAGERY EXTENDED FROM NEAR LIMON COLORADO TO NEAR IMPERIAL. THIS ACTIVITY HAS BEEN MOVING TO THE EAST NORTHEAST AND IS EXPECTED TO REMAIN MAINLY SOUTH OF THE FORECAST AREA THIS AFTERNOON. THE EXCEPTION IS ACROSS THE FAR SOUTHWESTERN COUNTIES WHERE 1 TO 2 INCHES IS POSSIBLE THIS AFTERNOON. ELSEWHERE...ANY ACCUMULATIONS ARE EXPECTED TO BE AN INCH OR LESS. AS OF 3 PM CST...UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES RANGED FROM 11 AT VALENTINE TO 17 AT OGALLALA. && .UPDATE... ISSUED AT 729 PM CST SUN DEC 8 2013 THE RAP AND HRRR TEMPERATURE AND WIND CHILL FORECASTS APPEAR TO BE ON TRACK WITH KVTN SHOWING A WIND CHILL OF -26F AT 7 PM CST. THERE ARE SOME MID CLOUDS MOVING IN FROM WY WHICH WILL LIMIT THE AMOUNT OF TIME FOR RADIATIONAL COOLING. THUS CONDITIONS ARE NOT FAVORABLE FOR ROCK BOTTOM LOWS BUT -10F TO -20F SHOULD DEVELOP ALONG AND WEST OF HIGHWAY 83 TONIGHT. TEMPS HAVE BEEN LOWERED IN THE NORTH AND A WIND CHILL WARNING IS IN PLACE FROM VALENTINE WEST TO GORDON. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 326 PM CST SUN DEC 8 2013 SHORT WAVE MOVING ACROSS THE NEB/KS BORDER...WHICH MODELS HAVE HANDLED FAIRLY WELL. LIGHT SNOW WILL BE TAPERING TO FLURRIES ACROSS PORTIONS OF SOUTHWEST AND CENTRAL NEBRASKA BEFORE ENDING LATER THIS EVENING. ADDITIONAL SNOWFALL COULD REACH UP TO THREE QUARTERS OF AN INCH...HOWEVER MOST AREAS IN THE SE CWA TO SEE A COUPLE OF TENTHS. CLEARING SKIES ARE ALREADY SEEN ON VISIBLE SAT ACROSS THE PANHANDLE AND NW NEB. HIGH PRESSURE WILL BEGIN TO NOSE DOWN INTO THE AREA TONIGHT...WHICH WILL COMBINE WITH THE SNOW PACK TO ALLOW FOR GOOD RADIATIONAL COOLING. RECENT LOWS HAVE BEEN BELOW GUIDANCE WHEN SKIES HAVE CLEARED...SO TOOK COOLER MAV GUIDANCE AND DROPPED A COUPLE OF DEGREES...WHICH MAYBE CONSERVATIVE FOR PORTIONS OF THE NW CWA...WHERE MORE THAN HALF A FOOT OF SNOW REMAINS ON THE GROUND. THIS PLACES LOWS IN THE -5 TO -15 DEGREE RANGE. NORTHWEST WINDS MOVING IN WITH THE CLEARING...ALTHOUGH THEY WILL BE DIMINISHING. THE COMBINATION OF LIGHT WINDS AND BITTER COLD TEMPS WILL ALLOW FOR WIND CHILLS TO FALL INTO THE -20 TO -30 RANGE...LOCALLY LOWER ACROSS NW ZONES. WILL GO WITH A WIND CHILL ADVISORY FOR ENTIRE CWA. TOMORROW MODELS HOLD 850 MB TEMPS FAIRLY STEADY...AND WITH MOSTLY SUNNY SKIES EXPECT HIGHS TO REBOUND A LITTLE WARMER THAN TODAY...HIGHS SHOULD REBOUND INTO THE TEENS TO NEAR 20. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 326 PM CST SUN DEC 8 2013 MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING CHALLENGES ARE TEMPERATURES...THEN LOW PRECIPITATION CHANCES FOR TUESDAY NIGHT. ON MONDAY NIGHT...A SURFACE TROUGH OF LOW PRESSURE WILL TRACK FROM THE CENTRAL PLAINS EAST INTO THE UPPER MIDWEST. LIMITED CAA WILL ACCOMPANY PASSAGE OF THE TROUGH. HOWEVER...IT WILL HELP TO KEEP THE LOW LEVEL WINDS MIXED ON MONDAY NIGHT...THUS MILDER TEMPERATURES ARE EXPECTED. ALBEIT...LOWS WILL STILL BE COLD WITH READINGS IN THE SINGLE DIGITS. ON TUESDAY...WESTERLY DOWNSLOPE WINDS WILL CONTINUE INCREASE SOMEWHAT TO 10 TO 15 MPH. DECIDED TO UNDERCUT GUIDANCE FOR HIGHS TUESDAY...BASED ON SNOW COVER AND LIMITED MIXING POTENTIAL. THIS LED TO HIGHS MAINLY IN THE 20S...WITH SOME TEMPS NEAR THE FREEZING MARK ACROSS THE FAR SOUTHWEST. ON TUESDAY NIGHT...AN ARCTIC COLD FRONT WILL BACK INTO NORTHERN AND NORTHEASTERN NEBRASKA WITH A NICE PV MAX ARRIVING OVERNIGHT. CROSS SECTIONS ACROSS NORTHERN NEBRASKA ARE INDICATIVE OF SOME WEAK LIFT IN THE DENDRITIC LAYER WHICH MAXES OUT AROUND 06Z WEDNESDAY. TOP DOWN SATURATION WILL HAVE TO OCCUR WITH ANY PCPN WHICH MAY FALL...SO WILL LIMIT POP MENTION TO SLIGHTS FOR NOW...AND KEEP POPS ACROSS THE NRN CWA AS CROSS SECTIONS NEVER MOISTEN UP ACROSS THE SRN CWA. ON WEDNESDAY SURFACE HIGH PRESSURE WILL BUILD INTO THE MID MISSOURI VALLEY. WINDS WILL SHIFT TO THE SOUTHWEST DURING THE AFTERNOON HOURS...AND WILL RECYCLE COLD AIR ACROSS THE FORECAST AREA. HIGHS WILL BE COLD...RANGING FROM THE MIDDLE TEENS IN THE NORTHEAST...TO THE UPPER 20S IN THE FAR SOUTHWEST. WEDNESDAY NIGHT THROUGH SUNDAY...THE MID RANGE MODEL SOLUTIONS CONTINUE TO INDICATE LOW AMPLITUDE WEST NORTHWESTERLY FLOW ACROSS THE CONUS FOR THE END OF THE WEEK INTO EARLY NEXT WEEK. BOTH THE ECMWF AND GFS SOLNS ARE TRENDING TOWARD THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EMBEDDED IN THE SRN STREAM TOWARD FRIDAY. BOTH SOLNS LIFT THIS ENERGY SOUTH OF THE AREA...SO A DRY FORECAST CONTINUES. AFTER TEMPERATURES TREND HIGHER FOR THURSDAY AND FRIDAY WITH HIGHS IN THE 30S...COOLER TEMPERATURES WILL ARRIVE ON FRIDAY NIGHT AS AN ARCTIC COLD FRONT BACKS INTO THE FORECAST AREA. HIGHS WILL BE COOLER IN THE 20S AND LOWER 30S SATURDAY...FOLLOWED BY 30S AND LOWER 40S FOR SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1112 PM CST SUN DEC 8 2013 VFR IS EXPECTED ALL AREAS TONIGHT THROUGH MONDAY EVENING. SCATTERED TO BROKEN COVERAGE OF MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS THE FCST AREA DURING THIS PERIOD. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON CST /11 AM MST/ MONDAY FOR NEZ007- 009-010-022>029-035>038-056>059-069>071. WIND CHILL WARNING UNTIL NOON CST /11 AM MST/ MONDAY FOR NEZ004>006-008-094. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...MASEK LONG TERM...CLB AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
116 AM EST MON DEC 9 2013 .SYNOPSIS... A SYSTEM WILL BRING A ROUND OF LIGHT FREEZING DRIZZLE TONIGHT THROUGH MORNING. MONDAY NIGHT THROUGH THURSDAY...ARCTIC AIR WILL WORK INTO THE AREA. THIS WILL INCLUDE DEVELOPING ACCUMULATING LAKE EFFECT SNOW SHOWERS EAST OF THE GREAT LAKES. && .NEAR TERM /THROUGH TODAY/... 1150 PM UPDATE...A QUICK UPDATE TO WX GRIDS AS FREEZING PRECIP/SLEET ALREADY OCCURRING ACROSS NE PA AND PARTS OF THE SOUTHERN TIER. THIS TRANSITION TO LIGHT FREEZING RAIN AND SLEET WILL RAPIDLY SPREAD NORTH ACROSS THE NRN CWA DURING THE NEXT SEVERAL HOURS AS MODEL SOUNDINGS CONTINUE TO INDICATE MOISTURE TOO SHALLOW FOR A DENDRITE ZONE. ALSO, DUE TO A LACK OF SIGNIFICANT LIFT DYNAMIC COOLING IS ALSO ABSENT. MOST AREAS WILL SEE LITTLE OR NO SNOWFALL PERHAPS AN INCH OVER NRN/ERN PTN OF FA. ALL AREAS WILL HAVE ICE ACCUMS UP TO ONE TENTH OF AN INCH WHICH WILL MAKE THE MORNING COMMUTE DIFFICULT. 1005 PM UPDATE... HV DELAYED PCPN FURTHER BY SVRL HRS AS NEPA IS SEEING VRY LITTLE PCPN ATTM, THO SRN TIER IS SEEING FLURRIES. KBUF 00Z RAOB STILL SHOWING DRY AIR IN THE LOWEST 200MB AND THIS IS BEING CONFIRMED BY OBS ACRS THE REGION. EMPHASIS NOW TURNS TO FRZG PCPN DRG THE OVRNGT HRS AS SNOW/SLEET DOES NOT APPEAR TO BE THE BIG CONCERN. ATMOS LOSES MOISTURE IN THE DENDRITE ZONE TONIGHT AS MOISTURE IN THE AREA IS GETTING THE SQUEEZE PLAY BTWN THE COASTAL LOW AND GREAT LKS LOW. THUS, HV UPDATED TO GO FRZG DRIZZLE AREAWIDE FOR TONIGHT WITH A GLAZE OF ICE EXPECTED BY MRNG. THUS WL KEEP THE ADVISORY GOING AS TEMPS RMN BLO FRZG AND ONLY VRY LGT QPF EXPECTED. PREV DISCUSSIONS BLO... 630 PM UPDATE... PRECIP IS TAKING QUITE AWHILE TO MV INTO FA AS IT SLOWLY WORKS ITS WAY THRU PA. ACRS NEPA, OBS ARE STILL REPORTING CIGS RANGING FM 6-10KFT AND HIGHER ACRS CNTRL NY. 18Z RAOB OUT OF KBUF SHOWING THE LOWEST 300MB STILL DRY, HELPING TO EVAPORATE QPF AS IT HEADS NWRD. APPEARS AS THO 18Z GFS BUFKIT SNDGS HV A BETTER HANDLE ON LOW-LVL DRY AIR WITH BLYR AT KAVP RMNG TOO DRY FOR SNOW THRU 00Z, WHEREAS NAM, RAP AND ARW SNDGS INDICATING SNOW SHUD HV BEEN FALLING FOR THE LAST SVRL HRS DOWN ACRS NEPA. THUS HV BACKED OFF ON POPS FOR EARLY THIS EVNG WITH CHC LIGHT SNOW IN NEPA NOT MVG IN FOR ANOTHER FEW HRS, SOMEWHERE BTWN 01Z AND 02Z. THIS AREA OF LIGHT SNOW WL GRADUALLY SPREAD NORTH MVG INTO SRN TIER BY 03Z AND OVRSPRD RMNDR OF THE AREA BY 06Z. QPF AMNTS EXPECTED TO BE VRY LGT WITH QPF TOTALS THRU MRNG < 0.10 INCHES. EXPECT SNOW TO CONT ACRS ENTIRE CWA THRU 06Z (A TAD LATER THAN PREVIOUSLY THOUGHT) BFR GRADUALLY MIXING WITH SLEET AND EVENTUALLY -FZRA/-FZDZ TWD DAYBREAK. EXPECT SNOW TO HANG ON LONGEST OVR NRN ONEIDA CNTY WHERE COLD AIR WL BE DEEPEST. HAVING SAID ALL THIS EXPECT JUST 1-2 INCHES OF SNOW AND SLEET ACCUMS, HIGHEST OVR EXTRM ERN SXNS FM MOHAWK VLY DOWN THRU WRN CATS. APPEARS LKLY THAT ALL AREAS WL SEE A GLAZE OF ICE BY MRNG, MAKING FOR HAZARDOUS TRAVEL DRG THE MRNG COMMUTE. 315 PM UPDATE... DOUBLE LOW SYSTEM...YET WE ARE IN BETWEEN...WITH ONE CENTER BY THE NORTHERN GREAT LAKES AND THE OTHER OFFSHORE OF NEW JERSEY. FORCING WITH THE SOUTHERN LOW HAS YIELDED A BAND OF HEAVY SNOW IN SOUTHEAST PA THROUGH NJ...AS ANYONE WATCHING THE PHILADELPHIA PRO FOOTBALL GAME CAN ATTEST. WE WILL STILL GET A PIECE OF THE SYSTEM...WITH TOP DOWN MOISTENING YIELDING A BATCH OF SNOW THIS EVENING SPREADING FROM SOUTHWEST TO NORTHEAST. HOWEVER...SHORTLY AFTER SNOW ARRIVES...SATURATED LAYER BECOMES SHALLOW TO POINT THAT TEMPERATURES WITHIN IT BECOME UNSUPPORTIVE OF ICE CRYSTAL FORMATION...SO QUICK SOUTH-TO-NORTH TRANSITION TO WINTRY MIX OF LIGHT SLEET AND FREEZING RAIN/DRIZZLE IS FORESEEN OVERNIGHT INTO EARLY MONDAY...AND EVENTUALLY PLAIN RAIN/DRIZZLE DURING THE DAY MONDAY. WINTER WEATHER ADVISORY FOR ENTIRE AREA STILL LOOKS GOOD YET AS PREVIOUSLY ADVERTISED THIS WILL DEFINITELY BE A LIGHT PRECIPITATION EVENT. IT HAPPENS TO INCLUDE LIGHT FREEZING RAIN/FREEZING DRIZZLE AND THUS THE POTENTIAL FOR HAZARDOUS TRAVEL CONDITIONS ON UNTREATED ROADS...NECESSITATING THE ADVISORY. ONLY FIGURING ON AN INCH OR LESS OF SNOW- SLEET ACCUMULATION /PERHAPS CLOSER TO 2 INCHES IN CATSKILLS TO ONEIDA COUNTY/...AND UP TO A TENTH OF AN INCH OF ICE ACCUMULATION...MOST PLACES LESS. NON-DIURNAL TEMPERATURES TONIGHT...SLOWLY CLIMBING FROM UPPER 20S THROUGH LOW 30S INTO MONDAY MORNING...EVENTUALLY REACHING HIGHS OF MID 30S TO LOW 40S DURING THE DAY. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... 130 PM UPDATE... COLD AIR ADVECTION WILL DOMINATE THE SHORT TERM PERIOD...AS WELL AS DEVELOPMENT OF WESTERLY-FLOW LAKE EFFECT SNOW FOR SOME. DEPARTURE OF SYSTEM WELL TO OUR NORTHEAST...AS WELL AS SHALLOW MOISTURE PROFILE AND WEST-SOUTHWEST FLOW...WILL KEEP THINGS FAIRLY QUIET MONDAY NIGHT. INTO TUESDAY THOUGH...850MB TEMPERATURES WILL DIP INTO THE LOWER TO MID TEENS BELOW ZERO CELSIUS WHILE INVERSION WILL RISE TO DENDRITIC GROWTH LAYER...BEGINNING TO INITIATE BETTER LAKE RESPONSES. NOT EXPECTING HEAVY ACCUMULATIONS TUESDAY ITSELF WITH WSW FLOW KEEPING LAKE ONTARIO BAND MAINLY NORTH...YET PERHAPS STILL SKIMMING NORTHERN ONEIDA COUNTY. HOWEVER...LAKE ERIE BAND MAY ACTUALLY STRETCH WELL EAST INTO AT LEAST SOUTHERN TIER-FINGER LAKES FOR AT LEAST SCATTERED SNOW SHOWERS AND PERHAPS BRIEF HEAVIER BURSTS. LAKE EFFECT CONTINUES TO BE FAVORABLE TUESDAY NIGHT INTO WEDNESDAY...AS 1000-500MB THICKNESSES DROP FURTHER INTO THE MID 510S TO LOWER 520S DECAMETER RANGE. HIGHS WEDNESDAY ONLY 20S AREAWIDE. MODEL SOUNDINGS SUGGEST DENDRITIC GROWTH TEMPERATURES DOMINATING THE 3-7 KFT AGL LAYER. PASSING SHORTWAVES THOUGH WILL FLUCTUATE LOW LEVEL WINDS...WHICH WILL PUSH THE BANDS AROUND AND ALSO COULD MIS ALIGN WINDS IN THE LOWEST LEVELS. WE WILL HAVE TO WATCH NORTHERN ONEIDA COUNTY CLOSELY IN MODEL TRENDS FOR POTENTIAL OF GETTING INVOLVED IN LAKE PROLIFIC ONTARIO SNOW BAND...WHICH MUCH IF NOT MOST OF THE TIME WILL REMAIN JUST TO THE NORTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 215 PM EST UPDATE... A VERY ACTIVE WEATHER PATTERN IS EXPECTED IN THE EXTENDED FORECAST. MINOR ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST AND LEANED TOWARDS WPC GUIDANCE. VERY BROAD UPPER LEVEL LOW WILL SLOWLY DRIFT NORTH AND EAST OF THE REGION RESULTING IN A MUCH COOLER AIR MASS OVER THE REGION... THUS LE SNOW SHOWERS WILL BE POSSIBLE THROUGH FRIDAY FOR CENTRAL NY. HIGH PRESSURE WILL BUILD ACROSS NEW ENGLAND THIS WEEKEND WHICH WILL HELP TEMPS CREEP CLOSER TOWARDS 32. WITH LARGE DIFFERENCE WITHIN GFS/ECMWF INTO THE WEEKEND KEPT PREVIOUS FORECAST WITH A SLIGHT CHANCE FOR SNOW SHOWERS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... 1230 PM UPDATE... LIGHT PRECIP WILL CONTINUE THIS MORNING. CIGS WILL FALL FROM MOSTLY MVFR TO IFR AT ALL BUT SYR AND ELM BY 15Z. SOME IFR CIGS ALREADY AT BGM AND AVP WHICH SHOULD CONTINUE FOR THE MOST PART. MUCH OF THE SNOW WILL BE LIGHT ENOUGH THAT VSBYS WILL STAY MVFR. THE SNOW WILL CHANGE TO SLEET THEN TO FREEZING DRIZZLE. AMOUNTS WILL BE LIGHT WITH QPF PROBABLY UNDER A TENTH OF AN INCH. TEMPERATURES SLOWLY RISE THIS MORNING SO THAT PLAIN RAIN AND DRIZZLE BETWEEN 12 AND 16Z. FIRST WILL BE AVP AND LAST RME TO CHANGE. VSBYS SHOULD IMPROVE TO VFR AS PRECIP ENDS AROUND 16Z BUT CIGS WILL REMAIN IFR/MVFR UNTIL 19 TO 00Z THEN IMPROVE TO VFR/MVFR. STAYING THAT WAY THIS EVENING. SE WINDS AT 5 TO 10 KTS WILL SHIFT TO SSW MIDDAY THEN TO W LATE AFTN. OUTLOOK... MON OVERNIGHT... MVFR/VFR. TUE/WED/THU...SCT MVFR SYR/RME IN LAKE EFFECT SNOW SHOWERS. VFR ELSEWHERE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR PAZ038>040-043-044-047-048-072. NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ015>018-022>025-044-045-055-056-062. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NYZ009-036-037-046-057. && $$ SYNOPSIS...MDP/PVN NEAR TERM...MDP/PVN/RRM SHORT TERM...MDP LONG TERM...KAH AVIATION...DJN/TAC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
504 AM EST MON DEC 9 2013 .SYNOPSIS... A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18 TUESDAY. LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5 TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED. WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z MONDAY. WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON- DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE. WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING. EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW. THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY 0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION. CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2 INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE FREEZING MARK. HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER 20S FOR THE COALFIELDS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV MOUNTAINS. DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES. DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... PERHAPS THE LAST BAND OF LIGHT RAIN UNDER 35 DEGREES MOVING SLOWLY EAST THROUGH AT LEAST 09Z. THEN...AREAS OF RAIN ARE EXPECTED TO EXIT THE EASTERN MOUNTAINS. HOWEVER...PERIODS OF IFR/LIFR WILL BE COMMON UNDER AREAS OF RAIN. A LOW LEVEL DECK AROUND 500 FEET IS EXPECTED TO FORM OR CONTINUE ACROSS MOST SITES THROUGH THE PREDAWN HOURS. AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING TO IFR/MVFR FOR REMAINDER OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... 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 MON 12/09/13 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 H M M M M M H H H H H HTS CONSISTENCY M M H H H H H M H H H H BKW CONSISTENCY H H M M M M M M M M M M EKN CONSISTENCY M M M M M M M M M L L L PKB CONSISTENCY M H M H H H L L L H H H CKB CONSISTENCY H H H H H H M M M M M H AFTER 06Z TUESDAY... IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY. && .EQUIPMENT... ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035- 036-046-047. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037- 038. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/50 NEAR TERM...ARJ SHORT TERM...50 LONG TERM...KTB AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
419 AM EST MON DEC 9 2013 .SYNOPSIS... A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE TONIGHT INTO TUESDAY. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18 TUESDAY. LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5 TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED. WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z MONDAY. WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON- DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE. WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... UPPER LEVEL SW FLOW FINALLY FLATTENS...BECOMING MORE ZONAL...IN THE WAKE OF A S/W TROUGH THAT CROSSES TUE. SYSTEM IN THE NEAR TERM IS ABOUT EXODUS BY 00Z TUE...THE START OF THE SHORT TERM...WITH PERHAPS LIGHT UPSLOPE PRECIPITATION WINDING DOWN. WHILE NOT AS MOISTURE RICH AS PREVIOUS SYSTEMS...JET DYNAMICS AND S/W FORCING IN THE BAROCLINIC ZONE SHOULD GENERATE A QUICK HITTING BAND OF PRECIPITATION THROUGH THE MIDDLE OHIO VALLEY EARLY TUE MORNING. ANOTHER BAND BRUSHES THE CENTRAL APPALACHIANS AS A SFC WAVE MOVES NE ALONG THE FRONT WHICH WILL BE OVER THE CAROLINAS AT THAT TIME. COLDER AIR MOVING IN MON NT WILL DRIVE H85 TEMPERATURES TO -6C TO -10C N BY TUE AFTERNOON...SO THE PRECIPITATION WILL TAKE THE FORM OF SNOW...SAVE FOR MIXED PRECIPITATION EARLY ON OVER THE CENTRAL APPALACHIANS. ANY UPSLOPE PRECIPITATION IN THE WAKE OF THIS EVENT TUE AFTERNOON IS BRIEF...AND HIGH PRESSURE BUILDS IN FOR A DRY AND COLD TUE NT...AND THEN HANGS ON FOR A DRY WED. USED ADJMET AND NAM FOR TEMPERATURES IN COLD ADVECTION MON NT...BLENDED IN ADJMET FOR HIGHS TUE AND BIAS CORRECTED ADJMET FOR LOWS TUE NT. BLENDED IN BIAS CORRECTED ADJMEX FOR HIGHS WED. OVERALL NO MAJOR CHANGES. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV MOUNTAINS. DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES. DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... PERHAPS THE LAST BAND OF LIGHT RAIN UNDER 35 DEGREES MOVING SLOWLY EAST THROUGH AT LEAST 09Z. THEN...AREAS OF RAIN ARE EXPECTED TO EXIT THE EASTERN MOUNTAINS. HOWEVER...PERIODS OF IFR/LIFR WILL BE COMMON UNDER AREAS OF RAIN. A LOW LEVEL DECK AROUND 500 FEET IS EXPECTED TO FORM OR CONTINUE ACROSS MOST SITES THROUGH THE PREDAWN HOURS. AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING TO IFR/MVFR FOR REMAINDER OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... 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 MON 12/09/13 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 H M M M M M H H H H H HTS CONSISTENCY M M H H H H H M H H H H BKW CONSISTENCY H H M M M M M M M M M M EKN CONSISTENCY M M M M M M M M M L L L PKB CONSISTENCY M H M H H H L L L H H H CKB CONSISTENCY H H H H H H M M M M M H AFTER 06Z TUESDAY... IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY. && .HYDROLOGY... THE LAST OF THE RIVER FLOOD WARNINGS AT BELINGTON ASSOCIATED WITH THE RAINFALL LAST THURSDAY AND FRIDAY...IS GONE. HAVE FLOOD WATCH FOR MUCH OF THE WV LOWLANDS AND INTO NE KY AS MORE RAINFALL IS EXPECTED TONIGHT INTO MONDAY...WHICH MAY CAUSE ADDITIONAL RISES ON RIVERS. THIS ADDITIONAL RAIN MAY ALSO CAUSE FLOODING ALONG SMALL CREEKS AND STREAMS. WILL NEED TO MONITOR TRENDS TONIGHT FOR WHERE THE BAND OF HEAVIEST PRECIPITATION SETS UP...AND THUS WHERE THE AREA OF HIGHEST CONCERN IS. && .EQUIPMENT... ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035- 036-046-047. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037- 038. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/ARJ/TRM/MZ NEAR TERM...ARJ SHORT TERM...TRM LONG TERM...KTB AVIATION...ARJ HYDROLOGY... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
107 AM EST MON DEC 9 2013 .SYNOPSIS... WARM FRONT LIFTS NORTH INTO TONIGHT. A LOW PRESSURE WAVE CROSSES LATER TONIGHT INTO MONDAY. A WEAK SYSTEM CROSSES LATE MONDAY NIGHT INTO TUESDAY. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY. && .NEAR TERM /THROUGH TODAY/... POPS AND WEATHER GRIDS REMAIN ON TRACK AS THE LAST BAND OF RAIN GRADUALLY MOVE EAST TOWARDS THE MOUNTAINS. TWEAKED SFC WINDS FOLLOWING THE LATEST SFC OBS AND THE RUC PROJECTION UP TO 12 HOURS. A BAND OF RAIN...SHOW SIGNS OF BREAKING UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5 TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED. WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z MONDAY. WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON- DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... UPPER LEVEL SW FLOW FINALLY FLATTENS...BECOMING MORE ZONAL...IN THE WAKE OF A S/W TROUGH THAT CROSSES TUE. SYSTEM IN THE NEAR TERM IS ABOUT EXODUS BY 00Z TUE...THE START OF THE SHORT TERM...WITH PERHAPS LIGHT UPSLOPE PRECIPITATION WINDING DOWN. WHILE NOT AS MOISTURE RICH AS PREVIOUS SYSTEMS...JET DYNAMICS AND S/W FORCING IN THE BAROCLINIC ZONE SHOULD GENERATE A QUICK HITTING BAND OF PRECIPITATION THROUGH THE MIDDLE OHIO VALLEY EARLY TUE MORNING. ANOTHER BAND BRUSHES THE CENTRAL APPALACHIANS AS A SFC WAVE MOVES NE ALONG THE FRONT WHICH WILL BE OVER THE CAROLINAS AT THAT TIME. COLDER AIR MOVING IN MON NT WILL DRIVE H85 TEMPERATURES TO -6C TO -10C N BY TUE AFTERNOON...SO THE PRECIPITATION WILL TAKE THE FORM OF SNOW...SAVE FOR MIXED PRECIPITATION EARLY ON OVER THE CENTRAL APPALACHIANS. ANY UPSLOPE PRECIPITATION IN THE WAKE OF THIS EVENT TUE AFTERNOON IS BRIEF...AND HIGH PRESSURE BUILDS IN FOR A DRY AND COLD TUE NT...AND THEN HANGS ON FOR A DRY WED. USED ADJMET AND NAM FOR TEMPERATURES IN COLD ADVECTION MON NT...BLENDED IN ADJMET FOR HIGHS TUE AND BIAS CORRECTED ADJMET FOR LOWS TUE NT. BLENDED IN BIAS CORRECTED ADJMEX FOR HIGHS WED. OVERALL NO MAJOR CHANGES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV MOUNTAINS. DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES. DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... PERHAPS THE LAST BAND OF LIGHT RAIN UNDER 35 DEGREES MOVING SLOWLY EAST THROUGH AT LEAST 09Z. THEN...AREAS OF RAIN ARE EXPECTED TO EXIT THE EASTERN MOUNTAINS. HOWEVER...PERIODS OF IFR/LIFR WILL BE COMMON UNDER AREAS OF RAIN. A LOW LEVEL DECK AROUND 500 FEET IS EXPECTED TO FORM OR CONTINUE ACROSS MOST SITES THROUGH THE PREDAWN HOURS. AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING TO IFR/MVFR FOR REMAINDER OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... 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 MON 12/09/13 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 M M H H M M M M M H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY M M H H M M M H H M H M EKN CONSISTENCY M M M M M M M M M M M L PKB CONSISTENCY H H M H H H H H L L L H CKB CONSISTENCY M H H M M M M M H M M M AFTER 06Z TUESDAY... IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY. && .HYDROLOGY... THE LAST OF THE RIVER FLOOD WARNINGS AT BELINGTON ASSOCIATED WITH THE RAINFALL LAST THURSDAY AND FRIDAY...IS GONE. HAVE FLOOD WATCH FOR MUCH OF THE WV LOWLANDS AND INTO NE KY AS MORE RAINFALL IS EXPECTED TONIGHT INTO MONDAY...WHICH MAY CAUSE ADDITIONAL RISES ON RIVERS. THIS ADDITIONAL RAIN MAY ALSO CAUSE FLOODING ALONG SMALL CREEKS AND STREAMS. WILL NEED TO MONITOR TRENDS TONIGHT FOR WHERE THE BAND OF HEAVIEST PRECIPITATION SETS UP...AND THUS WHERE THE AREA OF HIGHEST CONCERN IS. && .EQUIPMENT... ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLOOD WATCH THROUGH THIS AFTERNOON FOR WVZ005-006-013>016-018- 020-024>040. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037- 038. WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035- 036-046-047. OH...NONE. KY...FLOOD WATCH THROUGH THIS AFTERNOON FOR KYZ105. VA...FLOOD WATCH THROUGH THIS AFTERNOON FOR VAZ003-004. && $$ SYNOPSIS...KTB/TRM/MZ NEAR TERM...ARJ/MZ/SL SHORT TERM...TRM LONG TERM...KTB AVIATION...ARJ HYDROLOGY... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1125 PM CST SUN DEC 8 2013 .UPDATE...AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 844 PM CST SUN DEC 8 2013/ DISCUSSION...02 SURFACE ANALYSIS PLACES A WEAK QUASI-STATIONARY BOUNDARY/SURFACE LOW NEAR THE LOUISIANA/MISSISSIPPI/ALABAMA GULF COAST THIS EVENING. MEANWHILE...A RIDGE OF HIGH PRESSURE IS LOCATED ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY INTO PORTIONS OF THE MID SOUTH. TEMPERATURES AS OF 8 PM CST RANGE FROM THE MIDDLE 30S TO AROUND 40 DEGREES ACROSS WEST TENNESSEE NEAR THE TENNESSEE RIVER AND PORTIONS OF NORTHEAST MISSISSIPPI AND UPPER 20S TO LOWER 30S ALONG AND WEST OF THE MISSISSIPPI RIVER. KNQA/KGWX WSR-88D RADAR TRENDS INDICATE LIGHT RAIN SHOWERS ACROSS NORTHEAST MISSISSIPPI IN ASSOCIATION WITH A MID LEVEL SHORTWAVE TROUGH AND AN UPPER LEVEL JET STREAK MOVING ACROSS THE REGION. LATEST RUC SHORT TERM MODEL SEEMS TO BE HANDLING CURRENT TRENDS THE BEST WITH RESPECT TO PRECIPITATION. WILL MAKE ADJUSTMENTS TO LIMIT AND LOWER PRECIPITATION CHANCES OVERNIGHT TO EXTREME NORTHEAST MISSISSIPPI. AS OF 8 PM CST...VISIBILITIES ARE CURRENTLY RANGING FROM 4SM TO P6SM. LIGHT WINDS HAVE KEPT LOW LEVEL MOISTURE LIFTED AS A LOW STRATUS LAYER THUS FAR. WILL CONTINUE TO MONITOR SHORT TERM TRENDS FOR THE POSSIBLE DEVELOPMENT OF FOG/FREEZING FOG AND ANY HEADLINES IF IT BECOMES NECESSARY. WILL ALSO MAKE MINOR ADJUSTMENTS TO TEMPERATURES AND ALL OTHER ELEMENTS AS NEEDED TO ACCOUNT FOR LATEST TRENDS. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC PREV DISCUSSION... /ISSUED 536 PM CST SUN DEC 8 2013/ UPDATE...AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 320 PM CST SUN DEC 8 2013/ A SHARP TEMPERATURE GRADIENT IS OCCURRING ACROSS THE MIDSOUTH THIS EVENING. LOCATIONS SOUTH AND EAST OF A MEMPHIS TO JACKSON TENNESSEE LINE ARE REPORTING TEMPERATURES IN THE MID 30S TO LOWER 40S. NORTH AND WEST OF THIS LINE TEMPERATURES RANGE FROM 28-32 DEGREES. TEMPERATURES ALSO REMAIN NEAR FREEZING FARTHER SOUTH IN THE DELTA SUCH AS MARIANNA...TUNICA AND CLARKSDALE. PATCHY DENSE FREEZING FOG HAS FORMED ALONG THIS GRADIENT BETWEEN THE ARCTIC AIR AND THE WARMER AIR. WEST MEMPHIS...MILLINGTON...BLYTHEVILLE...DYERSBURG AND UNION CITY ARE REPORTING VISIBILITIES FROM A QUARTER MILE TO THREE QUARTERS OF A MILE. THUS FAR NO ICING HAS OCCURRED AS A RESULT OF THE FOG BUT A LITTLE WORRIED THAT THIS MAY CHANGE ONCE THE SUN GOES DOWN. WILL LET EVENING SHIFT MONITOR FOR ANY POTENTIAL ADVISORIES. MEANWHILE...RAIN CONTINUES TO PUSH NORTHWARD INTO NORTH MISSISSIPPI WHERE LOCATIONS ARE ABOVE FREEZING. THIS IS DUE TO A SFC LOW DEVELOPING ALONG A STATIONARY FRONT NEAR THE GULF COAST. MODELS INDICATE THE NORTHERN EXTENT OF THE PRECIPITATION COULD REACH INTO LOCATIONS THIS EVENING THAT ARE SITTING JUST ABOVE OR AT FREEZING CURRENTLY. AS TEMPERATURES DROP THIS EVENING THIS COULD CHANGE RAIN OVER TO FREEZING RAIN...BUT CONFIDENCE IS LOW THUS AGAIN WILL LET EVENING SHIFT MONITOR FOR ANY POTENTIAL ADVISORIES. WILL JUST MENTION A SLIGHT CHANCE OR CHANCE OF FREEZING RAIN IN THE FORECAST AS BEST CHANCES OF PRECIPITATION WILL OCCUR ACROSS NORTHEAST MISSISSIPPI WHERE LOCATIONS WILL REMAIN ABOVE FREEZING. ANOTHER SFC LOW WILL DEVELOP ALONG THE STATIONARY FRONT LOCATED ALONG THE GULF COAST BY MONDAY EVENING. THIS WILL BRING ANOTHER ROUND OF PRECIPITATION THAT WILL SKIRT NORTHEAST MISSISSIPPI. HOWEVER BY MONDAY EVENING...NORTHWEST WINDS WILL HAVE PUSHED ARCTIC AIR FURTHER SOUTH AND EAST THUS PRECIPITATION COULD FALL IN THE FORM OF FREEZING RAIN IF PRECIPITATION MAKES IT AS FAR NORTH AS NORTHEAST MISSISSIPPI. STAY TUNED. IN ADDITION...A SHORTWAVE WILL SWING ACROSS SOUTHERN MISSOURI AND WESTERN KENTUCKY MONDAY NIGHT. THIS COULD BRING A BRIEF SHOT OF LIGHT SNOW ACROSS PORTIONS OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL AND NORTHWEST TENNESSEE. ANY ACCUMULATIONS THAT WOULD OCCUR WOULD BE LESS THAN AN INCH. BY TUESDAY...ARCTIC HIGH PRESSURE SETTLES OVER THE MIDSOUTH. EXPECT DRY CONDITIONS WITH HIGHS RANGING FROM THE LOWER 30S TO LOWER 40S. A REINFORCING SHOT OF ARCTIC AIR WILL MOVE INTO THE AREA ON WEDNESDAY INTO WEDNESDAY NIGHT. LOWS WEDNESDAY NIGHT WILL RANGE FROM THE MID TEENS TO THE MID 20S. BY THURSDAY NIGHT...THE HIGH WILL SHIFT EAST TURNING WINDS AROUND TO THE SOUTH. THE NEXT LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA ON FRIDAY AND WILL BRING CHANCES FOR PRECIPITATION TO THE MIDSOUTH OVER THE NEXT WEEKEND. HOW QUICKLY THE ARCTIC AIR DEPARTS WILL DEPEND ON POSSIBLY PRECIPITATION TYPE FOR PORTIONS OF NEXT WEEKEND. THE 12Z ECMWF IS COLDER THAN THE 12Z GFS. FOR NOW HAVE TRIED TO GO WITH AN IN BETWEEN SOLUTION WHICH WOULD HAVE TEMPERATURES NEAR NORMAL AND WOULD KEEP PRECIPITATION IN THE FORM OF RAIN. KRM .AVIATION...06Z TAF CYCLE VIS HAS IMPROVED TO MVFR LEVELS OR HIGHER AT ALL SITES BUT CIGS REMAIN IFR EVERYWHERE EXCEPT JBR. NOT AS CONFIDENT THAT WE WILL SEE THE LIFR CIGS WE HAD IN PREVIOUS ISSUANCES. FEEL LIKE WE WILL SEE OVERALL SLOWLY IMPROVING CIGS WITH NEAR STEADY VIS FOR THE REMAINDER OF THE NIGHT. GUIDANCE WANTS TO CONTINUE TO LIFT CIGS THROUGH THE DAY EVEN TO VFR LEVELS...BASED ON EXPERIENCE...FEEL LIKE CLOUDS WILL LINGER LONGER THAN GUIDANCE SUGGESTS...BUT WILL BRING LEVELS TO 5KFT DURING THE AFTERNOON FOR ALL LOCATIONS EXCEPT TUP. RAIN AT TUP WILL BE LIGHT...WITH LITTLE TO NO PRECIPITATION ELSEWHERE. SOME PATCHY DRIZZLE MAY DEVELOP...AND MEM IS CURRENTLY REPORTING -DZ BUT DO NOT FEEL LIKE THIS WILL BE A PREVAILING CONDITION. WINDS GENERALLY LIGHT OVERNIGHT...LIGHT FROM THE NORTH TOMORROW. SOME LIGHT RAIN MAY MOVE BACK NEAR TUP LATE TOMORROW. JDS && .PRELIMINARY POINT TEMPS/POPS... MEM 31 39 27 38 / 40 10 20 10 MKL 31 38 24 37 / 50 10 20 10 JBR 25 31 24 32 / 10 10 20 10 TUP 37 43 33 42 / 80 30 60 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
356 AM CST MON DEC 9 2013 .SHORT TERM... Today and Tonight A cold front is currently moving through the Big Country and should be approaching the Interstate 10 corridor shortly after sunrise. Winds behind the front will become north and increase to about 8 to 12 mph, with colder air slowly filtering into West Central Texas. In addition, areas of freezing fog are evident just to the east of our area, which has slowly been creeping west. I expect this freezing fog to expand to a Throckmorton, to Coleman, to Mason line in the next few hours. A freezing fog advisory is in effect for parts of the Heartland through 9 AM, and I will continue to monitor trends for the possibility of expanding it north into parts of the Big Country and south toward Mason county. The HRRR is also indicating some post frontal fog across parts of the Big Country, which will need to be monitored. Stratus should fill in this morning behind the front, with much of the area becoming overcast by mid morning. Given the expected cloud cover and cold air advection, I lowered high temperatures slightly. Highs will range from the upper 20s north of Interstate 20, to the mid 40s across the Interstate 10 corridor. Cloudy skies through much of the overnight period will not support ideal radiational cooling conditions, but given the cold airmass that will be filtering into the region, I went ahead and lowered low temperatures slightly. Tuesday morning low temperatures will generally be in the teens to lower 20s across all of West Central Texas. Daniels .LONG TERM... Tuesday through Sunday As a fast moving shortwave trough moves through the Great Lakes region Tuesday night into Wednesday, a cold front will move into Texas, causing another brief cooling for Wednesday into Thursday. However, no precipitation is expected with the front. Lee troughing on Thursday will allow winds to quickly turn back to the south in our area, allowing temperatures to warm back up across the area Thursday and especially Friday. An upper level low initially off the coast of California on Monday will move across the Desert Southwest and into the Texas panhandle by Friday. As this low approaches, weak shortwaves will move across the area out ahead of it, interacting with moisture return and low level warm air advection, resulting in at least a slight chance for showers mainly Thursday afternoon and Thursday night, with some lingering showers moving out of the area on Friday. The upper level low will then move east towards the Mississippi Valley by Saturday, sending a cold front into the area. And while the cold front will slow the warming trend, the air mass behind the front will not be of arctic origin, so while we have gone cooler than the MOS guidance for Saturday and Sunday, temperatures should continue to trend closer to normal values through the weekend. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 26 18 39 27 42 / 10 5 0 0 0 San Angelo 35 19 44 26 46 / 10 5 0 0 0 Junction 46 22 47 24 52 / 10 10 5 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... FREEZING FOG ADVISORY until 9 AM CST this morning FOR THE FOLLOWING ZONES: Brown...Callahan...Coleman...McCulloch...San Saba. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1100 PM CST SUN DEC 8 2013 .UPDATE... Areas of dense fog over Central TX continue to build back to the west this evening and are right on the CWA border near San Saba and Brownwood. Given extremely low dewpoint depressions, a general east to southeast flow, and some residual sleet/ice pack on the ground, I expect this westward trend to continue. BUFKIT hydrolapse analysis of the NAM and RAP data indicate support this conceptual model. Thus, I have issued a Freezing Fog Advisory for areas along and east of a Baird, to Coleman, to Brady through 9 AM Monday. Visibilities are already down to 1/4 mile at Lampasas and Hamilton and RH values at Brownwood and Brady are greater than 93% currently. Given sub-freezing temperatures, any areas of dense fog will likely result in light ice accumulations on exposed surfaces. For aviation impacts, see the aviation section below. The remainder of the forecast package was in good shape. Minor changes were made to overnight temperatures, with lows across the Big Country increased by just a few degrees. Johnson && .AVIATION... The forecast terminals will begin to the period with benign conditions but I expected patchy freezing fog to develop overnight across West Central TX. At this time, the greatest threat appears to exist from KBWD to KBBD, but freezing fog will be possible at all terminals later tonight. Visibilities are the lowest at KBBD with only minor reductions forecast for the remaining forecast terminals. In addition to the fog, an arctic cold front will move south across West Central TX overnight, resulting in north to northeast winds of 8-12 kts and low ceilings. IFR ceilings are expected to develop late tonight and persist through midday, gradually improving into MVFR range during the afternoon and evening hours. Patchy, post-frontal freezing drizzle is a concern but low confidence does not warrant a mention in the current forecast package. Johnson && .PREV DISCUSSION... /ISSUED 540 PM CST SUN DEC 8 2013/ AVIATION... Another shallow arctic cold front will move through West Central TX late tonight and early Monday. Ahead of the cold front, we`ll see light winds, generally from the south, under clear skies. Sublimation over the sleet/ice pack will promote the development of patchy fog (and freezing fog) tonight. Enough spatial uncertainty exists that it extremely low visibilities will not be included in the current TAF package. I did, however, reduce visibilities to 3-5 statute miles in most areas, but amendments may be required in areas where fog does form as the forecast is likely too optimistic. Some of this fog may lift into an IFR stratus deck as well. As the front moves through the area, winds will shift to the north at 8-10 kts and stratus is expected to become more widespread. I would not rule out some patchy, post-frontal freezing drizzle. Again, however, the relatively low probability does not warrant mention in the TAF. I expect slow improvement in ceiling heights on Monday afternoon as the cold air deepens and lift over the frontal zone weakens. Johnson PREV DISCUSSION... /ISSUED 355 PM CST SUN DEC 8 2013/ SHORT TERM... Tonight and Monday Patchy freezing fog tonight and Arctic air Monday Clearing skies and light winds may allow the development of patchy freezing fog. This may potentially bring icing to bridges and overpasses, mainly after midnight, as temperatures fall to the dew point. Sleet from last week has been finally melting, with the visible satellite imagery still indicating sleet on the ground from the Big Country southward to San Angelo, Brady, and Brownwood. The sleet will help moisten the boundary level tonight, further enhancing the potential for fog. An arctic cold front will move into the Big country, moving through the I-20 corridor around 3 AM, and I-10 corridor around 9 AM. Low level cloud development and mixing should dissipate the fog as the arctic front moves through. Temperatures in the Big Country will likely stay in the 20s Monday with wind chills in the single digits in the morning. People should dress accordingly. LONG TERM... Monday Night through Sunday Cold temperatures will continue Monday night and Tuesday with a warming trend Wednesday through next weekend. A short wave trough will move across the Southern Plains Monday night with surface high pressure settling into the area into Tuesday. Temperatures will be very cold Monday night with overnight lows falling into the upper teens and lower 20s. The cold surface high will be overhead on Tuesday and despite some sunshine, temperatures will remain well below normal with afternoon highs ranging from the upper 30s along and north of the I-20 corridor, to the lower 40s along the I-10 corridor. By Wednesday, a broad upper level trough will cover much of the country with a weak upper low developing over the Baja region. A weak cold front will move across the area again on Wednesday but the associated surface high and coldest airmass will remain well northeast of the area through Thursday. Temperatures both Wednesday and Thursday will continue to be well below normal but will at least warm into the mid and upper 40s during the afternoon hours, with a few low 50s possible along the I-10 corridor. Southerly flow and increasing moisture return Thursday night and Friday ahead of the approaching upper low over the Desert Southwest. This system will bring a low chance of rainfall to mainly eastern sections Thursday night and early Friday. Models show another upper level trough and possible front affecting the area over the weekend but this system looks dry. Expect warmer temperature Friday through Sunday with highs in the 50s and lows in the 30s. && .PRELIMINARY POINT TEMPS/POPS... Abilene 20 28 17 38 24 / 0 5 5 0 5 San Angelo 25 37 20 43 24 / 0 5 5 5 5 Junction 28 45 23 45 24 / 5 10 10 5 5 && .SJT WATCHES/WARNINGS/ADVISORIES... FREEZING FOG ADVISORY until 9 AM CST Monday FOR THE FOLLOWING ZONES: Brown...Callahan...Coleman...McCulloch...San Saba. && $$ 25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
352 AM CST MON DEC 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND POTENTIAL FOR MORE SNOW LATER TONIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3 SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE -25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL. FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW FALLING JUST AHEAD OF THE SHORTWAVE. A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z. WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE AHEAD AND ISSUED AN ADVISORY FOR THEM. THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR PRECIPITATION THROUGHOUT. SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT. ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH 850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING... SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA. NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND. JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10 APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20 PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY 00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO WEDNESDAY. FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND... THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT... TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1100 PM CST SUN DEC 8 2013 SNOW WILL BE EXITING EAST OVER THE NEXT FEW HOURS AS THE RESPONSIBLE UPPER LEVEL SHORTWAVE HEADS TOWARD THE EASTERN GREAT LAKES. WINDS WILL PICK UP BY MONDAY MORNING...BECOMING GUSTY FROM THE WEST. THIS COULD RESULT IN A PERIOD OF DRIFTING/BLOWING OF THE FRESHLY FALLEN SNOW AT KRST. WITH SNOW AMOUNTS RELATIVELY SMALL THOUGH...IMPACT ON THE VSBY WILL LIKELY BE MINIMAL. CIGS WILL BE PROBLEMATIC AS A MIX OF MVFR/VFR CONTINUES PER LATEST SFC OBS...AND PINPOINTING A REASON FOR THE VARIABILITY IS DIFFICULT. WILL CONTINUE TO SIDE TOWARD MORE MVFR FOR THE OVERNIGHT HOURS...CLIMBING TO VFR...AND THEN BREAKING OUT INTO SCT SKIES FOR MONDAY AFTERNOON. CLOUDS WILL QUICKLY RETURN MONDAY NIGHT AS ANOTHER SHORTWAVE TROUGH SPINS ACROSS THE REGION. COULD SEE A PERIOD OF MVFR OVERNIGHT WITH SOME -SN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY FOR WIZ017-029. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1144 PM CST SUN DEC 8 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 856 PM CST SUN DEC 8 2013 CANCELLED WINTER WX ADVISORY FOR NORTHWEST PORTION OF FORECAST AREA AS HAVE HAD GENERALLY LESS THAN AN INCH UP THERE WITH VSBYS REMAINING IN THE 3 TO 5 MILES RANGE. EXPECT TO SEE AN INCH OR LESS ADDITONAL ACCUMULATION OVERNIGHT THERE. AREA OF LIGHT SNOW OVER FOX VALLEY LATE THIS EVENING ASSOCIATED WITH SHORTWAVE DISTURBANCE MOVING ACROSS SOUTHEAST WISCONSIN. VSBYS GENERALLY AROUND 2 MILES WITH SNOWFALL RATES A BIT HIGHER ALONG THE LAKESHORE AS LAKE ENHANCEMENT CONTINUES THERE. VSBYS FROM KEWAUNEE TO SOUTHEAST BROWN COUNTY...TO EAST OF OSHKOSH BEWTEEN 1 AND 2 MILES. BACK/WESTERN EDGE OF THIS AREA OF LIGHT SNOW APPROACHING THE FOX VALLEY THUS EXPECT LIGHT SNOW TO TAPER OFF FROM SOUTHWEST TO NORTHEAST OVER THE NEXT FEW HOURS...EXCEPT FOR THE LAKESHORE COUNTIES. UPSTREAM SHORTWAVE MOVING ACROSS IOWA CONTINUED TO LOOK UNIMPRESSIVE AS IT APPROACHES THE FORECAST AREA. DO NOT FEEL THIS FEATURE WILL BE ABLE TO DO MUCH TO FURTHER ENHANCE LIGHT SNOW OVER THE FORECAST AREA AFTER MIDNIGHT. LATEST RUC...NAM AND HRRR ARE ALL SUGGEST WEAK LIFT AND VERY MINIMAL QPF AMOUNTS. WILL KEEP ADVISORY GOING FOR NOW GIVEN LIGHT SNOW STILL FALLING OVER MUCH OF THE FORECAST AREA. MAY TRIM ADDITIONAL COUNTIES TO THE WEST OF THE FOX VALLEY FROM ADVISORY BEFORE MIDNIGHT IF RADAR RETURNS AND OBSERVED VSBYS REMAIN LACKLUSTER. HIGHEST SNOWFALL AMOUNTS HAVE GENERALLY BEEN AROUND 3 INCHES ALONG THE LAKESHORE FROM MANITOWOC TO DOOR COUNTY. ABOUT 2 INCHES AT NWS GREEN BAY AS OF 845 PM. JUST RECEIVED A REPORT OF 1.8 INCHES SO FAR IN EAST GREEN BAY. UPDATE ISSUED AT 644 PM CST SUN DEC 8 2013 SYSTEM AFFECTING THE FORECAST AREA HAS BEEN RATHER DISORGANIZED AND DISJOINTED THUS FAR. SO FAR...SNOWFALL AMOUNTS HAVE BEEN AROUND AN INCH OR SO THROUGH 6 PM. HOWEVER...WATER VAPOR IMAGERY SHOWS SOMEWHAT MORE ROBUST SHORTWAVE DISTURBANCE ENTERING SOUTHWEST WISCONSIN. THIS FEATURE HAS HELPED TO CREATE A SOMEWHAT MORE SOLID AND ORGANIZED AREA OF LIGHT SNOW ACROSS SOUTHEAST WISCONSIN WITH VSBYS GENERALLY BETWEEN ABOUT 1 AND 2 MILES. THIS AREA OF LIGHT SNOW CONTINUES TO DRIFT NORTHEAST AND WILL LIKELY CLIP THE SOUTHEAST PORTION OF THE FOX VALLEY GENERALLY SOUTH OF A LINE FROM OSH TO KEWAUNEE OVER THE NEXT FEW HOURS. FURTHER AS ANTICIPATED...AN AREA OF LAKE ENHANCED SNOW CONTINUES TO DEVELOP OVER CENTRAL LAKE MICHIGAN AND IS DRIFTING NORTHWEST. RADAR REFLECTIVITIES HAVE BEEN GRADUALLY INCREASING AND EXPNADING IN AREA COVERAGE OVER THE LAST HOUR. APPEARS ACTIVITY AHEAD OF APPROACHING SHORTWAVE ENTERING SOUTHWEST WISCONSIN CONTRIBUTING TO LES ENHANCEMENT OVER CENTRAL LAKE MICHIGAN VIA SEEDER-FEEDER MECHANISM. THUS...EXPECT TO SEE SOMEWHAT HIGHER SNOWFALL RATES ACROSS THE FOX VALLEY THIS EVENING IN ASSOCIATION WITH SHORTWAVE MOVING ACROSS SOUTHEAST WISCONSIN AND LAKE ENHANCEMENT OFF LAKE MICHIGAN. COULD SEE ANOTHER INCH OR PERHAPS TWO MY MIDNIGHT ESPECIALLY SOUTHEAST OFF A LINE FROM STURGEON BAY TO GREEN BAY TO OSHKOSH. LOOKING FURTHER UPSTREAM...PRIMARY SHORTWAVE DISTURBANCE NOW ENTERING NORTHWEST IOWA. THIS FEATURE IS ALSO FORECAST TO MOVE ACROSS THE SOUTHERN WISCONSIN AFTER MIDNIGHT AND MAY HELP TO KEEP SOME LIGHT SNOW GOING AFTER MIDNIGHT ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST AREA. HOWEVER...LOOKING AT SURFACE OBSERVATIONS OVER IOWA...VSBYS NOT VERY LOW AND WERE IN THE 2 TO 4 MILE RANGE. IN FACT THE LATEST HRRR AND RUC FORECASTS SEEM TO SIGNIFICANTLY DISSOLVE THE AREA OF QPF AS THIS FEATURE APPROACHES WISCONSIN. FORCING ACROSS THE NORTHWEST THIRD OF THE FORECAST AREA NOT EXPECTED TO BE VERY STRONG AND THUS FAR SNOWFALL RATES UP THERE HAVE BEEN QUITE LIGHT WITH VSBYS GENERALLY IN THE 2 TO 4 MILE RANGE. WILL SEE HOW THE SHORTWAVE MOVING OUT OF IOWA EVOLVES LATER THIS EVENING...BUT IF CURRENT TRENDS CONTINUE MAY NEED TO CANCEL ADVISORY UP THERE. FOR NOW WILL KEEP ADVISORY GOING OVER ENTIRE FORECAST AREA AND WILL REVIST A BIT LATER THIS EVENING. BOTTOM LINE IS IT APPEARS MOST SIGNIFICANT SNOWFALL WILL BE FOCUSED OVER THE FOX VALLEY AND LAKESHORE. APPEARS FINAL SNOWFALL TOTALS WILL BE ON THE LOW END OF CURRENT FORECAST. && .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 06Z TAF ISSUANCE ISSUED AT 1144 PM CST SUN DEC 8 2013 WEAK LOW PRESSURE WILL CONTINUE TO MOVE EAST OF THE FORECAST AREA OVERNIGHT. LIGHT SNOW WITH GENERALLY MVFR CIGS AND VSBYS WILL PREVAIL OVER MOST OF THE FORECAST AREA THROUGH 12Z MONDAY. FEW AREAS OF IFR CIGS OVER FOX VALLEY AND LAKESHORE WHERE LIGHT SNOW WILL BE A BIT HEAVIER THROUGH ABOUT 09Z. MVFR CIGS TO PERSIST UNTIL ABOUT 18Z MONDAY AND WILL BECOME SCT FROM WEST TO EAST DURING THE AFTERNOON. WESTERLY BOUNDARY LAYER WINDS WILL INCREASE SUBSTANTIALLY BY LATE MORNING WITH GUSTS OF 25 TO 30 MPH DURING THE AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ013-020>022- 030-031-035>040-045-048>050-073-074. && $$ UPDATE.........ESB SHORT TERM.....MPC LONG TERM......ECKBERG AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
759 AM EST MON DEC 9 2013 .SYNOPSIS... SURFACE WEDGE FLOW WILL BEGIN TO BREAK DOWN TODAY AHEAD OF ANOTHER APPROACHING COLD FRONT. THIS COLD FRONT WILL SLOWLY MOVE THROUGH LATE TONIGHT AND INTO TUESDAY...AND STALL JUST TO OUR SOUTH WEDNESDAY. DRY HIGH PRESSURE IS EXPECTED TO RETURN THE MID TO LATE WEEK...WITH ANOTHER SYSTEM ARRIVING NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONFIDENCE IS INCREASING FOR WEDGE TO HOLD ACROSS THE REGION THROUGH THE DAY. LATEST HOURLY RAP TEMPERATURE DATA SUPPORTS LOCAL WEDGE SCHEME AND KEEPS COLD AIR IN PLACE. STRONG SOUTH LOW LEVEL FLOW IN THE BOUNDARY LAYER ISENTROPIC LIFT RESULTING DRIZZLE AT TIMES...BUT WARM FRONT PROBABLY REMAINS TO THE SOUTH OF THE REGION. SO LOWERED TEMPERATURES AGAIN SEVERAL DEGREES... STRONGEST ISENTROPIC LIFT ACROSS PIEDMONT/NORTH MIDLANDS...SO EXPECT HIGHER CHANCE RAIN IN THAT REGION...LOWER CHANCE SOUTHEAST MIDLANDS/CSRA. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... CHANCES FOR RAIN WILL INCREASE DURING THE OVERNIGHT PERIOD AS THE AXIS OF HIGHER PRECIPITABLE WATER VALUES AND MOISTURE TRANSPORT GRADUALLY SHIFT EASTWARD AHEAD OF AN APPROACHING COLD FRONT. WILL CONTINUE THE GRADIENT IN POPS FROM LIKELY NORTHWEST TO LOW CHANCE IN THE SOUTHEASTERN PART OF THE FORECAST AREA. FAST MOVING SHORTWAVE ENERGY WILL PUSH EASTWARD INTO THE TENNESSEE AND OHIO VALLEYS LATE TONIGHT INTO TUESDAY WHICH WILL PUSH THE COLD FRONT ACROSS THE FORECAST AREA LATE TUESDAY MORNING INTO TUESDAY AFTERNOON. POOLING OF MOISTURE ON THE FRONT IS EXPECTED WITH PRECIPITABLE WATER VALUES RISING TO AROUND 1.5 INCHES. A STRONG 50 KT LOW LEVEL JET IS FORECAST TO PRECEDE THE FRONT WHILE SHIFTING ACROSS THE REGION AND COMBINING WITH INCREASED LOW LEVEL CONVERGENCE AND INCREASING UPPER FORCING AS THE FORECAST AREA FALLS WITHIN THE RIGHT ENTRANCE REGION OF THE UPPER JET. THEREFORE WILL TRANSITION LIKELY POPS ACROSS THE FORECAST AREA TUESDAY FROM WEST TO EAST WITH A SHARP DECREASE IN POPS LATE TUESDAY AFTERNOON AS THE UPPER FLOW BECOMES MORE ZONAL WHICH WILL PUSH THE FRONT EAST OF THE AREA WITH DRIER AIR WORKING IN FROM THE WEST. TEMPERATURES WILL REBOUND TO ABOVE NORMAL VALUES AHEAD OF THE FRONT WITH STRONG MIXING OF WARMER AIR ALOFT DOWN TO THE SURFACE. SKIES WILL CLEAR FROM WEST TO EAST TUESDAY AFTERNOON AND NIGHT AS LOW LEVEL FLOW BECOMES NORTHWESTERLY AS SURFACE HIGH PRESSURE BUILDS OVER THE AREA USHERING IN MUCH DRIER AIR TO THE REGION. COLD ADVECTION TUESDAY NIGHT WILL ALLOW LOW TEMPERATURES TO FALL INTO THE 30S ACROSS THE REGION. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... MEDIUM RANGE MODELS HAVE COME INTO BETTER AGREEMENT IN KEEPING THE STALLED FRONTAL BOUNDARY JUST TO OUR SOUTH ON WEDNESDAY AND CONFINING ANY ADDITIONAL PRECIPITATION ASSOCIATED WITH AN INVERTED TROUGH OFF THE COAST THROUGH WEDNESDAY NIGHT SOUTH AND EAST OF THE FORECAST AREA. WILL KEEP DRY FORECAST WEDNESDAY THROUGH FRIDAY AS PRECIPITABLE WATER VALUES REMAIN BELOW 0.5 INCHES. TEMPERATURES WILL BE BELOW NORMAL WEDNESDAY THROUGH FRIDAY WITH COOL HIGH PRESSURE SETTLED OVER THE SOUTHEAST. UNSETTLED WEATHER IS EXPECTED TO RETURN BY THE WEEKEND WITH GFS AND ECMWF COMING INTO BETTER AGREEMENT. A CUT OFF UPPER LOW OVER THE FOUR CORNERS REGION ON FRIDAY WILL OPEN UP AND PHASE WITH A DIGGING NORTHERN STREAM TROUGH OVER THE CENTRAL PLAINS AND MISSISSIPPI VALLEY BY FRIDAY NIGHT. MOISTURE WILL INCREASE QUICKLY AHEAD OF THE APPROACHING SYSTEM FRIDAY NIGHT WITH SOUTHERLY LOW LEVEL FLOW WITH RAIN EXPECTED TO OVERSPREAD THE REGION BY SATURDAY AS THE TROUGH MOVES EASTWARD INTO THE MID ATLANTIC REGION. WILL KEEP CHANCE POPS FRIDAY NIGHT BUT HAVE INCREASED POPS TO LIKELY FOR SATURDAY...AND HOLD ON TO CHANCE POPS SUNDAY WITH LOW CONFIDENCE IN THE EVENTUAL SPEED OF THIS SYSTEM. DO NOT EXPECT ANY PRECIP TYPE ISSUES DESPITE SOME INITIALLY DRY AIR TO OVERCOME. TEMPERATURES SAT/SUN SHOULD CONTINUE TO BE NEAR OR BELOW NORMAL. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... STRONG WEDGE CONDITIONS CONTINUE ACROSS THE AREA THIS MORNING. ALL TAF SITES REMAIN IFR/LIFR DUE TO CEILINGS AND SOME FOG AND DRIZZLE. MODEL TIME SECTIONS CONTINUE TO SHOW ABUNDANT LOW LEVEL MOISTURE THROUGH THE TAF PERIOD. MODELS STILL TRY TO HOLD ON TO THE WEDGE THROUGH MIDDAY. WILL KEEP LOW CONDITIONS IFR/LIFR FOR MUCH OF THE PERIOD...BECOMING MVFR BY THE AFTERNOON. LATEST GUIDANCE CONTINUES TO SHOW CONDITIONS DROPPING ONCE AGAIN TO IFR/POSSIBLE LIFR AFTER 00Z TUESDAY. EXTENDED AVIATION OUTLOOK..A COLD FRONT WILL SLOWLY MOVE THROUGH THE AREA TUESDAY. THERE WILL BE A CHANCE OF SHOWERS AND ASSOCIATED RESTRICTIONS WITH THE FRONT. THE FRONT IS FORECAST TO STALL JUST TO OUR SOUTH WEDNESDAY WITH HIGH PRESSURE BUILDING EASTWARD TO OUR NORTH. A RETURN TO VFR CONDITIONS POSSIBLE WEDNESDAY...BUT CONFIDENCE IS LOW. BY THURSDAY...HIGH PRESSURE BEGINS TO DOMINATE THE AREA AND VFR CONDITIONS ARE MORE CONFIDENT. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
623 AM EST MON DEC 9 2013 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH THROUGH THE AREA TODAY...THEN A COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTHWEST TUESDAY. HIGH PRESSURE WILL BUILD FROM THE WEST DURING THE MID TO LATE WEEK PERIOD. ANOTHER FRONTAL SYSTEM WILL IMPACT THE REGION DURING THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FOR THE SUNRISE UPDATE...DENSE FOG IS SPREADING INLAND SO THE DENSE FOG ADVISORY WILL BE RETAINED. LATEST RAP AND NAM-WRF DATA SUGGEST THE CAD WILL BE SLOWER TO ERODE THAN EXPECTED AND SHOWS HIGHS WELL INLAND STRUGGLING TO REACH THE MID 60S. HAVE OPTED TO LOWER HIGHS BY A CATEGORY INTO THE UPPER 60S ACROSS THE FAR INTERIOR ROW OF ZONES AND IF THE H3R PROVES CORRECT...THEN FAR INLAND AREAS STRETCHING BACK INTO THE CHARLESTON METRO AREA WILL ONLY PEAK IN THE LOWER-MID 60S. OBVIOUSLY THERE IS A BIG BUST POTENTIAL FOR THE TEMPERATURE FORECAST FOR TODAY...NOT UNCOMMON FOR CAD EROSION. IMPRESSIVE COLD AIR DAMMING /CAD/ REMAINS IN PLACE THIS MORNING WITH WIDESPREAD FOG...LOW CEILINGS AND INTERMITTENT DRIZZLE. PRESSURE FALLS ARE BEGINNING TO INCREASE ACROSS THE CORE OF THE CAD REGION PER 09/09Z ISALLOBARIC ANALYSIS SUGGESTING THE WEDGE IS BEGINNING TO STEADILY WEAKEN. AREA WEBCAMS AND SURFACE OBSERVATIONS SHOW STRATUS BUILD DOWN IS OCCURRING WHICH SHOULD TRANSLATE TO WIDESPREAD DENSE FOG PRIOR TO SUNRISE AS CEILINGS REACH THE GROUND. THE ONLY CONCERN IS THAT SURFACE WINDS ARE RUNNING A TAD HIGHER THAN EXPECTED...WHICH MAY LIMIT VISIBILITIES SOMEWHAT...BUT WINDS ARE FORECAST TO DROP OFF OVER THE NEXT FEW HOURS. A DENSE FOG ADVISORY REMAINS IN EFFECT FOR ALL ZONES UNTIL 10 AM. FOG MAY LINGER ALONG THE BEACHES A BIT LONGER WITH FOG LIKELY REMAINING TRAPPED UNDERNEATH A STRONG MARINE INVERSION. AS COLD AIR DAMMING BREAKS DOWN...A WARM FRONT WILL MOVE STEADILY NORTH TODAY ALLOWING A SIGNIFICANT RECOVERY IN TEMPERATURES FOR ALL AREAS. HIGHS IN THE MID-UPPER 70S LOOK QUITE REASONABLE GIVEN THE AMOUNT OF WARM AIR NOTED ATOP THE COLD AIR WEDGE. ISOLATED TO SCATTERED SHOWERS LOOK TO INCREASE LATER THIS AFTERNOON AS WARM AIR ADVECTION AND LOW-LEVEL JETTING INTENSIFY AHEAD OF AN APPROACHING COLD FRONT. POPS WILL BE LIMITED TO 20-30 PERCENT...HIGHEST ACROSS THE FAR WESTERN AREAS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...ONGOING WARM AIR ADVECTION AND LOW-LEVEL JETTING WILL KEEP TEMPERATURES RATHER MILD FOR DECEMBER WITH LOWS IN THE LOWER-MID 60S...EXCEPT UPPER 50S ACROSS PORTIONS OF ALLENDALE- SCREVEN-JENKINS COUNTIES. RAIN CHANCES WILL REMAIN RATHER STATIC FOR MUCH OF THE NIGHT...WITH POPS 20-30 PERCENT...BUT WILL BEGIN TO RAMP UP CLOSER TO 40 PERCENT ACROSS THE FAR WEST JUST BEFORE SUNRISE TUESDAY. MORE FOG WILL BE POSSIBLE AFTER MIDNIGHT...BUT CURRENT INDICATIONS ARE THAT THE FOG WILL NOT BE DENSE. THE ONLY EXCEPTION COULD BE ALONG THE COAST IF SEA FOG IMPACTS COASTAL COMMUNITIES. TUESDAY...A COLD FRONT WILL PROGRESS THROUGH THE FORECAST AREA DURING THE DAYTIME HOURS AND LIKELY BE OFFSHORE BY SUNSET. WILL CONTINUE TO INDICATE THE BEST RAIN POTENTIAL OF THE PERIOD TUESDAY...WITH POPS UP TO 50 PERCENT AS THE FRONTAL ZONE CROSSES SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. CONSIDERING GOOD AGREEMENT IN NUMERICAL MODEL SOLUTIONS...SUBSEQUENT FORECAST ISSUANCES MAY BE ABLE TO RAISE RAIN CHANCES EVEN HIGHER INTO THE LIKELY CATEGORY. THE WARMING EFFECTS OF PRE-FRONTAL COMPRESSION...AS WELL AS PERSISTENT SOUTHWEST/WEST FLOW THROUGH THE AFTERNOON...WILL SUPPORT HIGH TEMPERATURES ABOVE SEASONAL NORMALS IN THE UPPER 60S WEST TO LOWER 70S EAST. SHOWER COVERAGE WILL QUICKLY DIMINISH FROM WEST TO EAST IN THE WAKE OF THE DEPARTING COLD FRONT AFTER SUNSET...AND WITH COLD ADVECTION QUICKLY INITIATING...EXPECT TEMPERATURES TO RAPIDLY FALL DURING THE EVENING AND OVERNIGHT HOURS. LOW TEMPERATURES WILL RANGE FROM THE UPPER 30S INLAND TO THE MID 40S NEAR THE COAST AND SOUTH OF INTERSTATE 16. WEDNESDAY...THE INITIAL AREA OF SURFACE HIGH PRESSURE BUILDING IN THE WAKE OF THE COLD FRONT WILL ACTUALLY DIMINISH AS THE DAY PROGRESSES...TO BE REPLACED BY A NOTABLY STRONGER SURFACE HIGH FOLLOWING SHORTWAVE ENERGY WITHIN BROAD UPPER TROUGHING. NORTHEAST FLOW WILL STILL CONTINUE WITHIN THIS TRANSITIONING PATTERN AND SUPPORT A SIGNIFICANT COOLING TREND. EXPECT HIGH TEMPERATURES TO BE SUPPRESSED IN THE MID 50S NORTH TO THE LOW 60S FAR SOUTH...WHILE LOW TEMPERATURES REACH SIMILAR VALUES TO THE PREVIOUS NIGHT. SOME CONVERGENCE OVER THE NEARBY ATLANTIC WATERS AND ALONG THE PERIPHERY OF THE BUILDING SURFACE HIGH COULD ALSO SUPPORT ISOLATED TO SCATTERED SHOWER ACTIVITY OVER THE MARINE ZONES. HAVE MAINTAINED A CORRIDOR OF SLIGHT CHANCE POPS ACROSS THE EASTERN THIRD OF THE FORECAST AREA TO ACCOUNT FOR A SMALL POTENTIAL OF SOME INLAND SHOWER INTRUSION. THURSDAY...THE AMPLIFYING SHORTWAVE TROUGH WILL QUICKLY SLIP OFF THE EAST COAST...WHILE THE STRONGER DRY HIGH PRESSURE BUILDS OVER THE MID ATLANTIC STATES AND CAROLINAS. ANOTHER WAVE OF COLD ADVECTION WILL KEEP TEMPERATURES WELL BELOW SEASONAL NORMALS ONCE AGAIN...WITH HIGHS PEAKING ONLY IN THE 50S DESPITE SCATTERING SKY COVER AND IMPROVED INSOLATION. RAIN CHANCES WILL REMAIN BELOW 15 PERCENT THROUGH THE DAY. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... SURFACE HIGH PRESSURE WILL STEADILY TRACK OFF THE COAST AND INTO THE ATLANTIC WATERS THROUGH FRIDAY...AHEAD OF SOUTHERN STREAM SHORTWAVE ENERGY LIFTING INTO THE TENNESSEE VALLEY. MEDIUM RANGE MODELS REMAIN IN NOTABLE DISAGREEMENT REGARDING THE STRENGTH AND TRACK OF SYNOPTIC SCALE FEATURES ON SATURDAY...WITH THE GENERAL CONSENSUS BEING VARIATIONS OF A FRONTAL SYSTEM CROSSING THE FORECAST AREA ON SATURDAY. COOL TEMPERATURES AND RAIN-FREE CONDITIONS WILL CONTINUE FOR THE DAYTIME HOURS ON FRIDAY...BEFORE RAIN CHANCES QUICKLY INCREASE FROM WEST TO EAST FRIDAY NIGHT AND PEAK SATURDAY AFTERNOON. TEMPERATURES ON SATURDAY COULD BE A FEW DEGREES WARMER THAN PREVIOUS DAYS...BUT MUCH DEPENDS ON THE SPEED WITH WHICH THE FRONT MOVES THROUGH THE FORECAST AREA. ONCE THE COLD FRONT SHIFTS OFFSHORE BY SUNDAY MORNING...THE ASSOCIATED SURFACE LOW TO THE NORTH WILL INTENSIFY RAPIDLY OFF THE NEW ENGLAND COAST. THE SOUTHEAST STATES WILL ONCE AGAIN BECOME LOCATED WITHIN DRIER HIGH PRESSURE BEHIND THE DEPARTING COLD FRONT...WITH RAIN CHANCES EXPECTED TO STEADILY DECREASE SUNDAY. TEMPERATURES WILL UNDERGO ANOTHER COOLING TREND FOR SUNDAY AND MONDAY. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... LIFR CONDITIONS PERSIST AT BOTH TERMINALS WITH CIGS/VSBYS AT AIRFIELD MINIMUMS. LIFR CONDITIONS WILL PERSIST THROUGH MID- MORNING BEFORE SLOWLY LIFTING AS COLD AIR DAMMING BREAKS DOWN AND A WARM FRONT MOVES NORTH. THERE IS MUCH UNCERTAINTY ON THE EXACT TIMING OF WHEN CONDITIONS WILL RISE ABOVE IFR AND MVFR THRESHOLDS...BUT CURRENT THINKING FOR KCHS IS 16Z FOR IFR AND 1730Z FOR MVFR. AT KSAV...EXPECT LIFR THROUGH 15Z AND MVFR THROUGH 1630Z. VFR FOR LATE MORNING INTO THE AFTERNOON. LOW CLOUDS AND FOG ARE POSSIBLE AGAIN TONIGHT. CAPPED CONDITIONS AT LOW-END MVFR FOR NOW...HOWEVER IFR CONDITIONS ARE A POSSIBILITY. EXTENDED AVIATION OUTLOOK...LOW TO MODERATE RISK OF OCCASIONAL FLIGHT RESTRICTIONS WITH A COLD FRONT AND ASSOCIATED SHOWERS TUESDAY AFTERNOON/EVENING. && .MARINE... TODAY...RECENTLY EXPANDED THE MARINE DENSE FOG ADVISORY TO INCLUDE THE REMAINING SOUTH CAROLINA NEARSHORE ZONES AND EXTENDED THE EXPIRATION TIME TO 10 AM. ITS UNCLEAR EXACTLY FAR OFFSHORE THE MOST DENSE FOG RESIDES...BUT THERE IS ENOUGH EVIDENCE IN SATELLITE DATA AND COASTAL WEBCAMS TO JUSTIFY KEEPING THE ADVISORY IN PLACE. THE FOG WILL LIKELY LINGER FOR MUCH OF THE DAY AND POTENTIALLY BECOME INTERMINGLED WITH SEA FOG THIS AFTERNOON AS INCREASING DEWPOINTS ADVECT OVER THE COOLER SHELF WATERS. OTHERWISE... NORTHEAST WINDS WILL GRADUALLY TURN SOUTHERLY LATER THIS MORNING AND INCREASE TO 10-15 KT AS A WARM FRONT MOVES NORTH. SEAS WILL BE 2-4 FT. TONIGHT...SOUTH WINDS 10-15 KT WILL BECOME SOUTHWEST AND INCREASE TO 15-20 KT AS A COLD FRONT APPROACHES FROM THE WEST. THERE WILL LIKELY BE A CONTINUED RISK FOR AT LEAST PATCHY SEA FOG...BUT THE HIGHER WINDS SHOULD KEEP VISIBILITIES ABOVE 1 NM. SEAS WILL BUILD TO 3-5 FT OFFSHORE WATERS AND CHARLESTON COUNTY NEARSHORE WATERS TO 2-4 FT ELSEWHERE. TUESDAY THROUGH FRIDAY...A COLD FRONT WILL MOVE THROUGH THE FORECAST AREA ON TUESDAY...WITH MODERATE SOUTHERLY FLOW VEERING TO THE NORTH OVERNIGHT. MARGINAL SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE WITHIN COLD ADVECTION FOLLOWING THE FRONTAL PASSAGE TUESDAY NIGHT INTO EARLY WEDNESDAY. A BETTER CHANCE FOR ADVISORY CONDITIONS WILL THEN OCCUR THURSDAY...AS A STRONGER HIGH PRESSURE CENTER BUILDS INTO THE REGION AND TIGHTENS THE GRADIENT OVER THE WATERS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ087-088- 099>101-114>119-137>141. SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ040- 042>045-047>052. MARINE...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330-350- 352-354. && $$ ST/WMS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
927 AM EST MON DEC 9 2013 .UPDATE... THE NEAR TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 337 AM EST MON DEC 9 2013 HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY. TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /TODAY/... ISSUED AT 919 AM EST MON DEC 9 2013 INTRODUCING FLURRIES INTO FORECAST THROUGH MID AFTERNOON GIVEN WEAK RADAR RETURNS COUPLED WITH SURFACE OBSERVED LIGHT SNOW OCCURRING. DO NOT EXPECT ACCUMULATION THOUGH GIVEN NO VSBY DROP ACCOMPANYING CURRENT SNOW AND FLAKES QUITE SMALL. CLEARING ACROSS WC AND NW IL SHOULD WORK ITS WAY INTO WESTERN COUNTIES BY LATE AFTERNOON AS HIGH PRESSURE BUILDS IN BUT RETURN OF HIGH CLOUDS FROM SOUTHERN SYSTEMS APPROACH TO RETURN HIGHER DECKS BY NIGHTFALL. TEMPS TO HOLD FAIRLY STEADY THROUGH THE DAY GIVEN CLOUD DECK HOLDING AND COLD ADVECTION BEGINNING TO TAKE PLACE. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 337 AM EST MON DEC 9 2013 FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST PERIODS. TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN 2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL. NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH. WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME AREAS ACROSS THE SOUTH. FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM APPROACHES. AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL WEDNESDAY NIGHT AS SYSTEM EXITS. LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 333 AM EST MON DEC 9 2013 MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND TEMPERATURES THURSDAY AND FRIDAY. MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY. IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO ALL BLEND TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 091500Z TAF UPDATE/... ISSUED AT 921 AM EDT MON DEC 9 2013 CURRENT KIND RADAR SHOWING VERY LIGHT RETURNS WITH A FEW STATIONS REPORTING FLURRIES. RAP SOUNDINGS INDICATING VERY WEAK INSTABILITY UNDERNEATH THE INVERSION WHICH IS LIKELY CONTRIBUTING TO THE FLURRIES. WILL INTRODUCE AT ALL SITES THROUGH 17Z BUT EXPECT NO VISIBILITY RESTRICTIONS. OTHER CHANGE WAS TO INTRODUCE GUSTS THROUGH THE AFTERNOON. 12Z DISCUSSION FOLLOWS... ISSUED AT 605 AM EDT MON DEC 9 2013 MVFR CEILINGS WITH IFR CEILINGS POSSIBLE AT TIMES EARLY THIS MORNING WILL IMPROVE TO VFR BY LATE AFTERNOON. THEN SOME AREAS MAY BECOME MVFR CEILINGS SNOW LATE TONIGHT. LOW PRESSURE OVER THE GREAT LAKES WILL CONTINUE MOVING NORTHEAST AS HIGH PRESSURE OVER THE CENTRAL PLAINS BUILDS SLOWLY EASTWARD. LOOK FOR A GRADUAL IMPROVEMENT IN THE CEILINGS BUT REMAINING MVFR CEILINGS THROUGH MID AFTERNOON. AFTER THAT CEILINGS WILL RISE TO 3 THOUSAND AND LOWER CLOUDS MAY SCATTER OUT TOWARDS EVENING. A WEATHER DISTURBANCE WILL TRACK INTO THE OHIO VALLEY LATE TONIGHT BRINGING AN AREA OF SNOW OVER CENTRAL AND SOUTHERN SECTIONS. THIS MAY RESULT IN MVFR OR POSSIBLY IFR CEILINGS AND SNOW SOME AREAS FROM INDY AND SOUTHWARD LATE TONIGHT. WINDS WILL BE FROM THE WEST UP TO 12 KNOTS TODAY AND 8 KNOTS OR LESS TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...50 NEAR TERM...TUCEK SHORT TERM...50 LONG TERM....JH AVIATION...JH/RYAN 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
921 AM EST MON DEC 9 2013 .UPDATE... AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 337 AM EST MON DEC 9 2013 HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY. TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /TODAY/... ISSUED AT 337 AM EST MON DEC 9 2013 A BAND OF LIGHT SNOW HAS DEVELOPED ALONG A WEAK SURFACE TROUGH MOVING ACROSS CENTRAL INDIANA. THIS BAND OF SNOW WILL BE OUT OF MUCH OF THE FORECAST AREA SHORTLY. BEHIND THE SNOW VISIBILITIES GENERALLY IMPROVE WITH NO MENTION OF FREEZING DRIZZLE SEEN IN OBSERVATIONS. BASED ON THIS HAVE DECIDED TO END WINTER WEATHER ADVISORY AT ISSUANCE TIME. WILL CONTINUE WITH A SPECIAL WEATHER STATEMENT THOUGH MENTIONING SLICK CONDITIONS PERSISTING EVEN THOUGH FREEZING PRECIPITATION HAS ENDED. WILL KEEP FLURRIES IN THE GRIDS THROUGH 12Z. OTHERWISE EXPECT A LITTLE DECREASE IN CLOUDS DURING THE DAY...BUT STILL MOSTLY CLOUDY OVERALL. TEMPERATURES WILL FALL SOME IN COLD ADVECTION THIS MORNING AND THEN REBOUND A BIT THIS AFTERNOON. BASED ON EXPECTED TIME OF ARRIVAL OF COLDER AIR MOS HIGHS LOOK PRETTY GOOD FOR TODAY. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 337 AM EST MON DEC 9 2013 FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST PERIODS. TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN 2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL. NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH. WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME AREAS ACROSS THE SOUTH. FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM APPROACHES. AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL WEDNESDAY NIGHT AS SYSTEM EXITS. LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 333 AM EST MON DEC 9 2013 MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND TEMPERATURES THURSDAY AND FRIDAY. MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY. IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO ALL BLEND TEMPERATURES. && .AVIATION /DISCUSSION FOR THE 091500Z TAF UPDATE/... ISSUED AT 921 AM EDT MON DEC 9 2013 CURRENT KIND RADAR SHOWING VERY LIGHT RETURNS WITH A FEW STATIONS REPORTING FLURRIES. RAP SOUNDINGS INDICATING VERY WEAK INSTABILITY UNDERNEATH THE INVERSION WHICH IS LIKELY CONTRIBUTING TO THE FLURRIES. WILL INTRODUCE AT ALL SITES THROUGH 17Z BUT EXPECT NO VISIBILITY RESTRICTIONS. OTHER CHANGE WAS TO INTRODUCE GUSTS THROUGH THE AFTERNOON. 12Z DISCUSSION FOLLOWS. MVFR CEILINGS WITH IFR CEILINGS POSSIBLE AT TIMES EARLY THIS MORNING WILL IMPROVE TO VFR BY LATE AFTERNOON. THEN SOME AREAS MAY BECOME MVFR CEILINGS SNOW LATE TONIGHT. LOW PRESSURE OVER THE GREAT LAKES WILL CONTINUE MOVING NORTHEAST AS HIGH PRESSURE OVER THE CENTRAL PLAINS BUILDS SLOWLY EASTWARD. LOOK FOR A GRADUAL IMPROVEMENT IN THE CEILINGS BUT REMAINING MVFR CEILINGS THROUGH MID AFTERNOON. AFTER THAT CEILINGS WILL RISE TO 3 THOUSAND AND LOWER CLOUDS MAY SCATTER OUT TOWARDS EVENING. A WEATHER DISTURBANCE WILL TRACK INTO THE OHIO VALLEY LATE TONIGHT BRINGING AN AREA OF SNOW OVER CENTRAL AND SOUTHERN SECTIONS. THIS MAY RESULT IN MVFR OR POSSIBLY IFR CEILINGS AND SNOW SOME AREAS FROM INDY AND SOUTHWARD LATE TONIGHT. WINDS WILL BE FROM THE WEST UP TO 12 KNOTS TODAY AND 8 KNOTS OR LESS TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...50 NEAR TERM...50 SHORT TERM...50 LONG TERM....JH AVIATION...JH/RYAN 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 MARQUETTE MI
749 AM EST MON DEC 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 551 AM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT TERM. ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE DIMINISHING. TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850 MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING SNOW/LOCALIZED WHITEOUT CONDITONS IN WSW STATEMENT UNDER THE DOMINANT BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG BUILDING IN FM THE WEST. THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF 25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 519 AM EST MON DEC 9 2013 CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED. ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE REINFORCING SHOTS THROUGH THIS WEEKEND. TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS. EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F. LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8 INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH ATTM. A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR THE COLDEST LOCATIONS. THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY. COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 738 AM EST MON DEC 9 2013 KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THE DAY. CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW. MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF NEXT SYSTEM FROM THE NOTRHERN PLAINS. KCMX...MVFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO HEAVY LAKE EFFECT SNOW BY MID MORNING AS WINDS VEER TO THE WEST AND BECOME GUSTY AND THIS WILL CONTINUE INTO THE EVENING HRS. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE TONIGHT AS LES BAND SHIFT OF THE AREA. KSAW...EXPECT VFR CONDITIONS THROUGH MUCH OF THE PD IN W-SW FLOW. WSW WINDS WILL LIKELY GUST OVER 20KT FOR A PERIOD THIS AFTERNOON. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 551 AM EST MON DEC 9 2013(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 FOR GALES. THE FIRST TROUGH WILL PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR 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... WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ014- 085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR LSZ244-245-265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244- 263-264. GALE WARNING FROM 4 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247. GALE WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
552 AM EST MON DEC 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 551 AM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT TERM. ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE DIMINISHING. TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850 MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING SNOW/LOCALIZED WHITEOUT CONDITONS UNDER THE DOMINANT BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG BUILDING IN FM THE WEST. THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF 25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 519 AM EST MON DEC 9 2013 CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED. ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE REINFORCING SHOTS THROUGH THIS WEEKEND. TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS. EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F. LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8 INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH ATTM. A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR THE COLDEST LOCATIONS. THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY. COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1155 PM EST SUN DEC 8 2013 WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS CONTINUING OVERNIGHT. 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 AND THIS WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 551 AM EST MON DEC 9 2013(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 FOR GALES. THE FIRST TROUGH WILL PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR 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... WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ014- 085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR LSZ244-245-265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244- 263-264. GALE WARNING FROM 4 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247. GALE WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...07 MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
520 AM EST MON DEC 9 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...(TUESDAY THROUGH SUNDAY) ISSUED AT 519 AM EST MON DEC 9 2013 CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED. ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE REINFORCING SHOTS THROUGH THIS WEEKEND. TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS. EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F. LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8 INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH ATTM. A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR THE COLDEST LOCATIONS. THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY. COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1155 PM EST SUN DEC 8 2013 WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS CONTINUING OVERNIGHT. 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 AND THIS WILL CONTINUE THROUGH THE REST OF THE TAF PERIOD. && .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 THIS MORNING FOR MIZ014- 085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR LSZ244-245-265>267. HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244- 263-264. GALE WARNING FROM 4 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR LSZ264. GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247. GALE WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...KLUBER AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
331 AM MST MON DEC 9 2013 .SHORT TERM...VALID FOR TDY AND TUE... WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH. TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55 MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY 21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE 70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA. NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/. WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00 UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED IN TIME WITH A LATER FORECAST RELEASE. TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F /MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING. TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE. THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO BE FAIRLY MOIST. TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE WESTERN ZONES. BORSUM && .AVIATION... FAST MOVING COLD FRONT WILL MOVE THROUGH EASTERN AND CENTRAL MONTANA BRINGING INCREASED WINDS...BLOWING SNOW AND SNOW SHOWERS. BEST CHANCE FOR SNOW WILL BE FOR EASTERN MONTANA WITH BLOWING SNOW BEING THE BIGGEST PROBLEM FOR KBIL AND KLVM. VERY STRONG WINDS ARE POSSIBLE FOR KLVM WITH DRIFTING AND BLOWING SNOW CREATING IFR CONDITIONS AT TIMES. KBIL WILL SEE WINDS GUSTS TO 45 MPH WITH MVFR CONDITIONS DUE TO BLOWING SNOW. KMLS WILL SEE LOWER CEILINGS IN THE SNOW SHOWERS WITH IFR CONDITIONS AT TIMES. KSHR WILL SEE CONDITIONS STAY MOSTLY VFR BUT WILL APPROACH MVFR CONDITIONS LATER IN THE AFTERNOON. BORSUM && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 019 014/023 005/029 020/033 018/034 015/034 024/036 1/Q 16/S 51/B 11/B 11/B 11/B 11/B LVM 016 010/022 007/026 020/032 021/034 019/032 024/033 2/J 24/S 42/J 11/N 12/J 11/B 11/N HDN 022 012/022 901/027 014/035 015/032 012/032 022/036 2/J 28/S 51/B 11/B 11/E 11/B 12/B MLS 020 009/016 907/023 010/031 013/026 010/028 020/035 9/J 38/S 21/B 11/B 12/J 11/B 22/B 4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036 8/J 47/S 21/B 00/B 01/B 11/B 22/B BHK 016 009/013 910/017 009/029 012/022 010/027 018/033 9/J 56/S 11/B 01/B 11/B 11/E 12/B SHR 023 008/024 901/027 014/036 016/034 014/033 022/038 2/J 25/S 51/B 01/B 12/J 11/B 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR ZONES 28-29-34-35-39-41-42-56-63-65-66. WIND CHILL ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR ZONES 30>33-36>38-57-58. WINTER WEATHER ADVISORY IN EFFECT FROM 11 AM THIS MORNING TO 11 PM MST THIS EVENING FOR ZONES 30>33-36>38-57-58. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EST MON DEC 9 2013 .SYNOPSIS... A SLOW-MOVING FRONTAL SYSTEM WEST OF THE APPALACHIANS THIS MORNING WILL DRIFT ACROSS OUR REGION TONIGHT AND TUESDAY. CHILLY HIGH PRESSURE WILL BUILD INTO OUR REGION TUESDAY NIGHT AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM MONDAY... NOT A LOT OF CHANGE NEEDED TO THE FORECAST THIS MORNING. THE CAD AIRMASS IS FAIRLY WELL ENTRENCHED AND WILL STRUGGLE TO ERODE TODAY. WHILE THE DEPTH OF THE RESIDUAL COLD POOL HAS DECREASED ON THE 12Z KGSO RAOB...THERE IS STILL A UNIFORM 40KT FLOW AT 850MB AND ENOUGH WARM ADVECTION TO KEEP STATIC STABILITY STRONG AND THE CAD LOCKED IN. RAP AND HRR SOUNDINGS KEEP THE ENTIRE CWA MURKY WELL ON INTO TONIGHT. THE CURRENT TEMP FORECAST IS AT THE LOWEST END OF THE GUIDANCE SPECTRUM...SHOWING TEMPS RANGING FROM LOWER 40S TO UPPER 50S. THE BIGGEST POTENTIAL FOR ERROR WILL BE BETWEEN THE TRIANGLE AND THE COASTAL PLAIN AS THE CAD BOUNDARY TRIES TO RETREAT NORTH AND WESTWARD. REGARDING POPS...THE AXIS OF DEEPEST MOISTURE IS CURRENTLY OVER WESTERN NC...AHEAD OF THE SLOW MOVING COLD FRONT WEST OF THE MOUNTAINS. THE NARROW RAIN BAND THAT CURRENTLY EXTENDS FROM WEST OF KCLT TO KGSO AND AND INTO VA APPEARS TO BE LINKED TO ISENTROPIC LIFT BETWEEN 295K AND 305K...WHICH WEAKENS THIS AFTERNOON AS ANOTHER WAVE OF LOW PRESSURE BEGINS TO FORM TO OUR SOUTHWEST ALONG THE FRONT. EVEN IF A LULL DEVELOPS...DRIZZLE WILL CONTINUE...SO HIGH POPS WILL BE MAINTAINED....PARTICULARLY WEST OF HWY 1. -SMITH TONIGHT: S/W ENERGY OVER THE CENTRAL ROCKIES WILL PUSH EASTWARD TODAY INTO TONIGHT... HELPING TO PUSH A COLD FRONT EASTWARD TOWARDS OUR REGION... WITH A SURFACE LOW DEVELOPING ALONG THE WEDGE FRONT (AHEAD OF THE APPROACHING COLD FRONT) SOMEWHERE ACROSS OUR SOUTHEAST/JUST TO THE SOUTH OF OUR REGION LATE TONIGHT. THIS SURFACE LOW AND CONTINUED MID LEVEL S/W ENERGY EMBEDDED IN THE SOUTHWESTERLY MID LEVEL FLOW WILL HELP SUPPORT A GOOD CHANCE OF RAIN AREAWIDE. TEMPS MAY ACTUALLY RISE OR HOLD STEADY OVERNIGHT WHERE THE CAD HOLDS TODAY. WILL GO WITH LOWS RANGING FROM THE LOW TO MID 40S NW TO LOW TO MID 50S SE. -BSD && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM MONDAY... TUESDAY...THE SURFACE LOW THAT DEVELOPS ALONG A FRONT SITUATED SW-NE ACROSS CENTRAL NC WILL AID TO ENHANCE LOW LEVEL CONVERGENCE OVER OUR REGION. ALOFT...A STRONG JET STREAKING ACROSS THE EASTERN LAKES INTO SOUTHERN NEW ENGLAND WILL INCREASE UPPER LEVEL DIVERGENCE OVER THE VIRGINIAS AND NC WHILE THE MID LEVEL S/W RESPONSIBLE FOR GENERATING THE SURFACE WAVE OVERHEAD WILL QUICKLY SHEAR NEWD ACROSS THE TN AND MID OH VALLEY. THE COMBINATION OF THE AVAILABLE LIFT AND MOISTURE SUGGEST RAIN SHOULD BE WIDESPREAD ACROSS THE REGION TO START THE DAY TUESDAY. MODEL GUIDANCE HAS VARIED AS TO WHERE THE AXIS OF "HEAVIEST" PRECIP (A QUARTER TO A HALF INCH) WILL SET-UP. HOWEVER...00Z GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT...FAVORING THE EASTERN PIEDMONT AND COASTAL PLAIN. STILL...BETTER DYNAMICS ALOFT WILL RESIDE OVER THE NW PIEDMONT. AT THIS TIME PLAN TO BROADBRUSH THE PRECIP AMOUNTS ACROSS THE REGION WITH TWO TO THREE TENTHS EXPECTED IN THE 12Z-18Z TUESDAY TIME FRAME. MID LEVEL S/W WILL QUICKLY SHEAR OUT TO THE NE TUESDAY AFTERNOON...PROPELLING THE SURFACE FRONT EASTWARD TO THE COAST BY TUESDAY AFTERNOON. THUS...SHOULD SEE PRECIP TAPER OFF WEST-TO-EAST TUESDAY AFTERNOON ACROSS CENTRAL NC. DEVELOPING NW FLOW IN THE LOWER LEVELS WILL LEAD TO DECREASING CLOUDINESS LATE IN THE DAY. DEVELOPING DOWNSLOPE FLOW WILL INITIALLY OFFSET COLD AIR ADVECTION. RESIDUAL CAD AIR MASS ACROSS THE NORTH-NW PIEDMONT SHOULD HOLD TEMPS IN THE 40S. EXPECT WARMER TEMPS OVER THE SOUTHERN COUNTIES WHERE TEMPS IN THE 50S (AROUND 60 FAR SE) PROBABLE. COLDER DRIER AIR WILL OVERSPREAD CENTRAL NC TUESDAY NIGHT AS A MODIFIED CANADIAN HIGH PRESSURE SYSTEM BUILDS INTO THE REGION. PARENT HIGH EXPECTED TO BE CENTERED OVER THE CENTRAL APPALACHIANS BY EARLY WEDNESDAY WITH A SURFACE RIDGE EXTENDING INTO NC. THUS...WHILE EARLY TUESDAY EVENING WILL BE A BIT BREEZY...LOOKS PLAUSIBLE FOR SFC WINDS TO DECOUPLE AFTER MIDNIGHT. THIS WILL ALLOW TEMPS TO FALL INTO THE 20S BY DAYBREAK WEDNESDAY ACROSS THE NORTH...AND NEAR 30 ACROSS THE SOUTH. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 330 AM MONDAY... WEDNESDAY THROUGH FRIDAY...RELATIVELY TRANQUIL WEATHER PERIOD ANTICIPATED FROM MID WEEK TO THE END OF THE WEEK AS BROAD UPPER TROUGH COVERS THE EASTERN TWO-THIRDS OF THE NATION. THE NORTHERN BRANCH WILL BE DOMINATE IN THE BEGINNING...KEEPING THE STORM TRACK MAINLY ACROSS THE NORTHERN PLAINS-GREAT LAKES AND NEW ENGLAND. THE SURFACE HIGH THAT COVERS OUR REGION WEDNESDAY WILL QUICKLY SCOOT EWD BY LATE WEDNESDAY BUT IS REPLACED BY ANOTHER CHILLY HIGH THAT BUILDS INTO THE MID ATLANTIC IN THE WAKE OF A MID LEVEL S/W CROSSES THE GREAT LAKES INTO NEW ENGLAND. THUS OUR CURRENT STRETCH OF BE LOW NORMAL TEMPS WILL CONTINUE. HIGH TEMPS WED AND THU WILL BE IN THE 40S WHILE MIN TEMPS WILL BE IN THE 20S TO AROUND 30. SATURDAY INTO SUNDAY...OPERATIONAL GFS AND ECMWF OFFER A SIMILAR SOLUTION FOR THE UPCOMING WEEKEND WEATHER PATTERN...IN SHARP CONTRAST TOT E 12Z MODEL RUNS WHICH DEPICTED A SOLUTION VERY SIMILAR TO OUR CURRENT WEATHER PATTERN. MODEL GUIDANCE NOW ADVERTISING A RETURN FLOW REGIME BECOMING ESTABLISHED FRIDAY NIGHT INTO SATURDAY...AHEAD OF A FRONTAL SYSTEM DOMINATED BY A S/W IN THE NORTHERN STREAM. THIS FRONTAL SYSTEM CROSSES OUR REGION SATURDAY NIGHT WITH CHILLY HIGH PRESSURE BUILDING INTO OUR REGION SUNDAY. FOR NOW WILL CONFINE THE BEST CHANCE FOR PRECIP TO SATURDAY AND KEEP IT ALL LIQUID. IF PRECIP COMES INTO THE REGION EARLY ENOUGH FRIDAY NIGHT...MAY START OUT AS A WINTRY MIX BEFORE QUICKLY TRANSITIONING TO ALL RAIN. TEMPS EXPECTED TO REMAIN BELOW NORMAL AND HIGHLY DEPENDENT UPON PRECIP COVERAGE. HIGHS IN THE 40S TO AROUND 50. LOWS TEMPS IN THE 30S FRIDAY NIGHT AND 30S TO AROUND 40 SATURDAY NIGHT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 730 AM MONDAY... 24-HR TAF PERIOD: ADVERSE AVIATION CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. EXPECT LIFR CEILINGS THIS MORNING TO CONTINUE THROUGH AT LEAST MID MORNING... WITH VISBYS POSSIBLY DROPPING TO A MILE OR LESS OVER THE NEXT COUPLE OF HOURS AS WELL (POSSIBLY LASTING UNTIL MID MORNING TOO). PERIODS OF RAIN AND DRIZZLE WILL BE POSSIBLE AT KGSO/KINT/KRDU TODAY... WITH MORE PATCHY RAIN AND DRIZZLE AT KRWI AND KFAY. EXPECT CIGS WILL BE VERY SLOW TO IMPROVE TODAY... AND MAY ONLY IMPROVE TO IFR CIGS GIVEN THE CAD AIRMASS OVER CENTRAL NC. IN ADDITION TO THE POOR CIGS/VISBYS AND RAIN/DRIZZLE... SOUTHWESTERLY WINDS OF AROUND 40-50 KTS ARE EXPECTED AT AROUND 2 KFT ABOVE THE SURFACE TODAY... CREATING LOW LEVEL WINDS SHEAR CONDITIONS. THUS... HAVE ADDED LLWS TO THE TAFS FOR TODAY. EXPECT WINDS AT AROUND 2 KFT TO WEAKEN BETWEEN 21-00Z TODAY. LIFR CONDITIONS ARE AGAIN EXPECTED TONIGHT... AS CIGS LOWER AND VISBYS DROP AFTER 00-03Z. CHANCES FOR RAIN/DRIZZLE WILL CONTINUE AS WELL. LOOKING AHEAD: ADVERSE CONDITIONS (IFR/MVFR AND PERHAPS LIFR) ASSOC/W THE COLD AIR DAMMING WEDGE WILL MOST LIKELY LINGER INTO THE DAY TUESDAY AS A COLD FRONT APPROACHES FROM THE WEST. VFR CONDITIONS WILL RETURN TUE NIGHT AS DRY HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST. VFR/DRY CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE WORK WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...BSD/SMITH SHORT TERM...WSS LONG TERM...WSS AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
638 AM CST MON DEC 9 2013 .UPDATE... ISSUED AT 638 AM CST MON DEC 9 2013 NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME. ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20 BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18 UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CST MON DEC 9 2013 THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING. THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS AFTERNOON. OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE EXPECTED TO BE THE STRONGEST. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 332 AM CST MON DEC 9 2013 THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC ZONE OVER THE NORTHERN PLAINS. CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME. COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS THE FORECAST AREA. THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE. SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 638 AM CST MON DEC 9 2013 ANOTHER MORNING OF SCATTERED STRATUS DECKS WITH FLURRIES THAT ARE HARD TO SEE ON SATELLITE AND RADAR WILL CONTINUE. ALTHOUGH THE SATELLITE HAS SHOWN A DECREASING TREND IN STRATUS OVER THE PAST FEW HOURS AND HAVE STARTED EVERYONE OFF MAINLY CLEAR OR WITH ONLY A SCATTERED STRATUS DECK AND NO FLURRIES. THEREAFTER...AN ALBERTA CLIPPER WILL IMPACT WESTERN AND CENTRAL NORTH DAKOTA MONDAY AFTERNOON AND EVENING. IFR CONDITIONS IN SNOW...BLOWING SNOW AND STRONG NORTHWEST WINDS ARE EXPECTED. && .BIS WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 PM CST /2 PM MST/ THIS AFTERNOON TO MIDNIGHT CST /11 PM MST/ TONIGHT FOR NDZ001>004-009>012- 017>019-021-031>033-040-041-043-044. WIND CHILL ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NDZ001>005-009>013-017>023-025-031>037-040>048-050-051. && $$ UPDATE...TWH SHORT TERM...AYD LONG TERM...TWH AVIATION...TWH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
637 AM EST MON DEC 9 2013 .SYNOPSIS... A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 630 AM UPDATE... UPDATE TO CANCEL REMAINING WINTER WX ADVISORY AND WARNING FOR EASTERN MOUNTAINS. A FEW ISOLATED PATCHES OF MAINLY FREEZING DRIZZLE WITH VERY LIGHT ACCUMULATIONS MAY STILL BE POSSIBLE FOR ANOTHER HOUR OR SO THIS MORNING ACROSS THE FAR EASTERN PORTIONS OF THE EASTERN MOUNTAIN COUNTIES. PREVIOUS DISCUSSION... MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18 TUESDAY. LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5 TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED. WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z MONDAY. WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON- DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE. WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING. EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW. THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY 0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION. CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2 INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE FREEZING MARK. HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER 20S FOR THE COALFIELDS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV MOUNTAINS. DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES. DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... LIFR CONDITIONS WILL PREVAIL THIS MORNING AS THE LAST AREAS OF RAIN ASSOCIATED WITH LAST COLD FRONT EXITS EAST OF THE MOUNTAINS LATE THIS MORNING. PERIODS OF IFR/LIFR VISIBILITIES ARE POSSIBLE DURING THE PREDAWN HOURS...PERHAPS LASTING UNTIL 14Z AT SOME PLACES. ANOTHER ROUND OF SNOW SHOWERS WILL APPROACH FROM THE NORTHWEST LATER TONIGHT FOR IFR/LIFR CONDITIONS ALOND THE SHOWER. AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING TO IFR/MVFR FOR REMAINDER OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... 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. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY H H H H H H M M M H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY M M M M M M M M H H H H EKN CONSISTENCY H H H M M M L H H H H H PKB CONSISTENCY H M H M M H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z TUESDAY... IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY. && .EQUIPMENT... ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ NEAR TERM...ARJ/50 SHORT TERM...50 LONG TERM...KTB AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
548 AM EST MON DEC 9 2013 .SYNOPSIS... A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18 TUESDAY. LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5 TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED. WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z MONDAY. WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON- DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE. WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING. EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW. THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY 0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION. CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2 INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE FREEZING MARK. HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER 20S FOR THE COALFIELDS. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV MOUNTAINS. DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES. DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... LIFR CONDITIONS WILL PREVAIL THIS MORNING AS THE LAST AREAS OF RAIN ASSOCIATED WITH LAST COLD FRONT EXITS EAST OF THE MOUNTAINS LATE THIS MORNING. PERIODS OF IFR/LIFR VISIBILITIES ARE POSSIBLE DURING THE PREDAWN HOURS...PERHAPS LASTING UNTIL 14Z AT SOME PLACES. ANOTHER ROUND OF SNOW SHOWERS WILL APPROACH FROM THE NORTHWEST LATER TONIGHT FOR IFR/LIFR CONDITIONS ALOND THE SHOWER. AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING TO IFR/MVFR FOR REMAINDER OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... 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. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY H H H H H H M M M H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY M M M M M M M M H H H H EKN CONSISTENCY H H H M M M L H H H H H PKB CONSISTENCY H M H M M H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z TUESDAY... IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY. && && .EQUIPMENT... ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035- 036-046-047. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037- 038. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ NEAR TERM...50 SHORT TERM...TRM LONG TERM...KTB AVIATION...ARJ HYDROLOGY... EQUIPMENT...
AREA FORECAST DISCUSSION
NWS PORTLAND OR
400 AM PST MON DEC 9 2013 .SYNOPSIS...ANOTHER VERY COLD NIGHT AS ARCTIC HIGH PRESSURE REMAINS DOMINANT OVER THE PACIFIC NORTHWEST. LOWER PRESSURE OFFSHORE CONTINUES TO DRIVE WEAK EASTERLY FLOW THROUGH THE COLUMBIA GORGE AND INTO THE PORTLAND AREA. A WEAK CLIPPER SYSTEM WILL PUSH DOWN FROM THE YUKON LATER TODAY...BRINGING A CHANCE OF SNOW AND OR FREEZING DRIZZLE MAINLY FOR OUR NORTHERN ZONES INTO TUESDAY. WEDNESDAY SHOULD REMAIN CHILLY AND DRY...THOUGH A LITTLE WARMER THAN THE PAST COUPLE DAYS AS OUR AIR MASS SLOWLY MODERATES. THE NEXT SYSTEM LOOKS STRONGER...AND MAY ENCOUNTER A STUBBORN LOW-LEVEL COLD AIR MASS AS PRECIPITATION SPREADS ONSHORE. THIS MAY RESULT IN MORE FROZEN OR FREEZING PRECIPITATION BEFORE A PACIFIC AIR MASS FINALLY TAKES OVER LATE IN THE WEEK. && .UPDATE...UPDATED HEADLINES BELOW. CONFIDENCE WAS NOT HIGH ENOUGH TO PUSH BACK THE ADVISORY FOR THE METRO AREA TO AFTER THE EVENING COMMUTE AS GUIDANCE IS STILL MIXED...SO FOR NOW KEPT THE 4 PM START TIME. .SHORT TERM...TONIGHT THROUGH WEDNESDAY... ONE LAST BITTERLY COLD NIGHT OUT THERE TONIGHT BEFORE THE SLOW PROGRESSION OUT OF THE COLDSNAP BEGINS. SEEING SOME OF THAT WITH THE COAST REMAINING GENERAALLY IN THE 20S. IT IS A BALMY 3 DEGREES IN EUGENE AND PLENTY OF TEENS INLAND. TEMPS AND DEWPOINTS ARE UP A LITTLE FROM LAST NIGHT WHICH SHOULD PREVENT WIDESPREAD SINGLE DIGITS. LOWER CLOUDS ARE ROLLING INTO THE COAST THIS MORNING...AND KLGX RADAR DEPICTS SOME SHOWER ACTIVITY OFFSHORE THAT IS SOMEWHAT DYING OUT ON THE LEADING EDGE. LATEST HI-RES GUIDANCE SUGGESTS THAT NOT A WHOLE LOT OF INLAND PROGRESS THIS MORNING AS THE FLOW IS STILL MORE NORTHERLY ALOFT...BUT LIKELY SOME LIGHT SNOW OR FLURRIES FOR THE S WA/N OR COAST AND COAST RANGE. A SOMEWHAT CHALLENGING FORECAST COMING UP THE NEXT FEW DAYS AFTER THE NEAR TERM AS SEVERAL WEAK WAVES MOVE THROUGH BUT MIXED SIGNALS WITH REGARDS TO PRECIPITATION. COULD SEE SOME VERY LIGHT SNOW/FLURRIES OR SOME FREEZING DRIZZLE.AFTER THIS MORNING SEVERAL MODELS BRING LIGHT PRECIPITATION (0.02" QPF OR LESS) INTO THE INTERIOR THIS AFTERNOON. CURRENT KLGX DATA WOULD SUGGEST THAT PRECIPITATION WILL CONTINUE WORKING INLAND...BUT MAY HAVE PROBLEMS WITH THE DRY AIR MASS. MEANWHILE THE HRRR AND NAM KEEP PRECIPITATION CONFINED TO COAST AND COAST RANGE WHERE TEMPERATURE PROFILES BEGIN TO WARM GIVEN THE WEAK ONSHORE FLOW TO THE POINT WHERE PRECIP TYPE WOULD CHANGE TO RAIN OR MAYBE RAIN-SNOW MIX. MEANWHILE INLAND THE PROFILE WILL REMAIN ALL BELOW FREEZING. AFTER THAT THERE IS A MORE DISTINCT WAVE OFF THE COAST OF NORTHERN B.C. THAT WILL DROP S.E. AND PROVIDE A BIT MORE ORGANIZED LIFT TONIGHT INTO EARLY TUESDAY. THE MOISTURE LAYER LOOKS TO BE RATHER SHALLOW. THESE SITUATIONS TEND TO FAVOR FREEZING DRIZZLE...BUT ONLY IF YOU TAKE THEM FOR FACE VALUE AND DO NOT CONSIDER THE INITIAL AIRMASS THAT THE CLOUD FORMED IN OR THE AIRMASS THE SATURATED CLOUD IS MOVING INTO. SOUNDINGS SUGGEST THE TOP OF THE MOIST LAYER AROUND -5 TO -7C. IT IS INCORRECT TO SUGGEST THAT THERE WILL BE NO ICE CRYSTALS PRESENT IN THE CLOUD EVEN AT THESE TEMPERATURES...JUST A QUESTION OF IF THERE ARE ENOUGH. CANNOT IGNORE THE FACT THERE MAY ALSO BE SOME FREEZING DRIZZLE WHICH IF HITTING THE COLD ROADS WOULD FREEZE LIKE THE SNOW DID THE OTHER DAY. THAT SAID...AN INVESTIGATION OF DUAL-POLARIZATION DATA FROM KLGX AND SIMPLY DUE TO THE FACT THAT REFLECTIVITY RETURNS ARE AS HIGH AS 30-40 DBZ SUGGEST THAT P-TYPE...AT LEAST CURRENTLY AND WITH THE FIRST BATCH COMING IN IS SNOW AND NOT FREEZING DRIZZLE. THE 0Z QUILLAYUTE SOUNDING DOES SUGGEST A WARM LAYER ABOVE THE MOIST LAYER.. BUT THE POTENTIAL OF FREEZING DRIZZLE CANNOT BE IGNORED AS THE LOWER LEVEL PROFILE WARMS AND REDUCES ICE CRYSTAL AVAILABILITY ESPECIALLY TOWARDS TUESDAY. AND ANY ACCUMULATING FREEZING DRIZZLE WOULD WARRANT AN ADVISORY...ALSO DUE TO THE FACT DEWPOINTS WILL BE MUCH HIGHER MONDAY NIGHT INTO TUESDAY MORNING...ROADS HAVE THE POTENTIAL TO BE QUITE HAZARDOUS...REGARDLESS OF THE PRECIP TYPE OR HOW MUCH/HOW LITTLE SNOW ACTUALLY FALLS. SREF PLUMES KEEP ANYWHERE FROM LIGHT SNOW ACCUMS TO UP TO AN INCH IN THE METRO. MODELS CONTINUE TO FAVOR THE KELSO/CASTLE ROCK AREA AND THE I-5 CORRIDOR IN WASHINGTON FOR THE MOST QPF. THEREFORE SEE NO REASON AT LEAST AT THIS TIME TO CHANGE THE HEADLINE...BUT WILL FOCUS ON FREEZING DRIZZLE/SNOW POTENTIAL AND ROAD IMPACTS. SINCE THE CENTRAL VALLEY DOES NOT LOOK TO SEE MUCH SNOW...I CAN FORESEE A SITUATION WHERE IF FREEZING DRIZZLE DOMINATES AND THE PRECIP GETS A BIT FARTHER SOUTH...THAT AN ADVISORY WOULD BE WARRANTED...BUT CONFIDENCE IS LOW. DO STILL THINK THAT 1-2" ARE POSSIBLE IF THE P-TYPE REMAINS SNOW MAINLY NORTH OF THE COLUMBIA RIVER AND ALSO TOWARDS ST HELENS/SCAPPOOSE. I HOPE THIS DOES NOT COME BACK TO HAUNT ME...BUT AM CONTEMPLATING TO REMOVING THE CENTRAL WILLAMETTE VALLEY FROM THE WINTER WX ADVISORY...AS QPF IN THESE AREAS DOES NOT SUPPORT AT THAT MUCH IN THE WAY OF SNOW. IF FREEZING DRIZZLE IS THE MORE DOMINANT P-TYPE...THAN AN ADVISORY WOULD THEN BE WARRANTED. WILL WORK UP THE WSW HERE WITH REFINED TIMING AND FINAL DECISIONS SHORTLY AND SEND AN AMENDED AFD WITH THE HEADLINES. THE MAIN JET ENERGY COMING OUT OF WESTERN CANADA SHOULD SHIFT FARTHER EAST BY WEDNESDAY...ALLOWING SOME CLEARING AND POSSIBLY ANOTHER CLEAR CALM AND CHILLY MORNING FOR SOME AREAS WED MORNING. EXPECT THERE TO THEN BE FOG/FREEZING FOG. AFTER BURN OFF AND WITH SOME SUNSHINE AND A SOMEWHAT MODERATED AIR MASS...MOST AREAS SHOULD BE ABLE TO GET ABOVE FREEZING WEDNESDAY. HAVE DRIED OUT THE FORECAST FOR WEDS AND WEDNESDAY NIGHT WITH THE EXPECTED TREND OF BACKING OFF THE ARRIVAL OF THE PACIFIC SYSTEM WITH A COLD AND STRONG UPPER RIDGE IN PLACE. /KMD LEFT PREVIOUS DISCUSSION IN PLACE FOR THE LATTER PART OF THE SHORT TERM FROM THE EVENING SHIFT AS MUCH OF THIS SHIFT WAS SPENT FINE TUNING THE DETAILS THROUGH WEDNESDAY NIGHT.... NO DOUBT THIS IS AN HISTORIC COLD AIR MASS. WHICH BRINGS US TO OUR NEXT FORECAST CHALLENGE...THE PRECIPITATION TYPE EXPECTED FROM OUR NEXT EVENT. CONSIDERING THE MAGNITUDE OF COLD ASSOCIATED WITH THIS AIR MASS...IT IS VERY HARD TO BELIEVE WEAK CLIPPER SYSTEMS WILL BE SUFFICIENT TO ERODE THE COLD AIR ENTRENCHED OVER THE PACIFIC NORTHWEST. WE CONTINUE TO DISAGREE WITH MODEL GUIDANCE THAT SUGGESTS THE COLD AIR WILL SCOUR OUT QUICKLY...AND OUR TEMPERATURE AND PRECIPITATION TYPE FORECAST REFLECTS THAT ALL THE WAY INTO THURSDAY. WEAGLE .LONG TERM...NO CHANGES TO THE GRIDS OTHER THAN TO BACK OFF ON POPS A BIT TO START THURSDAY SO REST OF THE DISCUSSION REMAINS UNCHANGED...WILL LET THE DAY SHIFT REVISIT THE CHANGE IN TIMING AND IMPACTS ON THERMAL PROFILES...WEDNESDAY NIGHT THROUGH SUNDAY...OVERALL NO CHANGES TO THE THINKING BEHIND THE EXTENDED FORECAST. DID SOME MANIPULATION OF THE GRIDS TO ATTEMPT TO BETTER EXPRESS THE MIXED PRECIPITATION POTENTIAL WITH THE LATE WEEK SYSTEM. WEAGLE PREVIOUS DISCUSSION FOLLOWS...THE WELL ESTABLISHED COLD ARCTIC AIR MASS WILL BEGIN TO MODERATE AS FLOW ALOFT BECOMES MORE WESTERLY. TEMPERATURES LOOK TO TREND BACK TO SEASONAL NORMALS THROUGH THE SECOND HALF OF NEXT WEEK. THE 12Z GFS AND ECMWF ARE A BIT SLOWER TO BRING A SYSTEM ONSHORE EARLY THURSDAY SO HAVE ADJUSTED POP GRIDS TO REFLECT THIS. FORECAST MODELS BRING THE HEAVIEST PRECIP ONSHORE MIDDAY THURSDAY...WITH THE GFS SOLUTION ABOUT 6 HOURS FASTER. THERE REMAINS SOME CONCERN THAT THE MODELS ARE TOO QUICK TO WARM THE AIR MASS AFTER THIS PERIOD OF RECORD-SETTING COLD...SO IT IS POSSIBLE THAT THIS PRECIPITATION MAY BEGIN IN THE FORM OF SNOW OR FREEZING RAIN. THIS IS PARTICULARLY THE CASE FOR UPPER HOOD RIVER...THE COLUMBIA RIVER GORGE..AND THE NORTHERN WILLAMETTE VALLEY. OTHERWISE RAIN AND CASCADE SNOW IS EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT. THERE MAY BE A BRIEF DRY PERIOD AT LEAST PART OF THE DAY SATURDAY AS LOW LEVEL FLOW WILL TURN SOUTHERLY BEFORE THE THE NEXT SYSTEM ARRIVES SATURDAY AFTERNOON OR EVENING BRINGING RAIN ACROSS THE FORECAST AREA.CULLEN && .AVIATION...VFR CONDITIONS THIS AM...WITH POCKETS OF FOG IN S WILLAMETTE VALLEY. CLOUDS INCREASING ALONG OREGON COAST...AND SHOULD PERSIST THROUGH TUE AM. FLURRIES ON THE COAST THIS AM. CIGS ON S WASH/N ORE COAST WILL LOWER TO MVFR AFTER 16Z...WITH OCCASIONAL MVFR VIS WITH BURSTS OF SNOW. NOT MUCH CHANGE ON COAST FOR TONIGHT...BUT INLAND CIGS WILL DROP TO LOW VFR OR MVFR WITH MVFR VIS IN OCCASIONAL LIGHT SNOW ACROSS N TAF SITES. KPDX AND APPROACHES...VFR WITH LIGHT EAST WINDS CONTINUE. WILL HAVE INCREASING LOW VFR CLOUDS THIS AM...WITH SOME OCCASIONAL FLURRIES FROM 20Z THROUGH 06Z TUE. CIGS WILL LOWER TO MVFR AFTER 03Z...WITH INCREASING THREAT OF SNOW LATE OVERNIGHT INTO TUE AM. ROCKEY. .MARINE...BENIGN WEATHER THROUGH WED. HIGH PRES OVER PAC NW MAINTAINS LIGHT OFFSHORE FLOW THROUGH WED. WILL WILL TURN MORE W TO SW TUE AND WED AS HIGH WEAKENS AND LOWER PRES APPROACHES FROM THE W. SEAS HOLDING AT 2 TO 4 FT TODAY AND TUE...THEN BUILD SLIGHTLY LATER TUE AND WED. STRONG COLD FRONT WILL ARRIVE ON THU...WITH S GALES EXPECTED. SEAS WILL BUILD BACK CLOSER TO 10 FT. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...WEATHER WEATHER ADVISORY... 1 PM TODAY TO 1 PM TUE FOR LOWER COLUMBIA. 4 PM TODAY TO 1 PM TUE FOR NORTH WILLAMETTE VALLEY INCLUDING THE GREATER PORTLAND METRO AREA. WA...WINTER WEATHER ADVISORY... 7 AM TO 10 PM TODAY FOR SOUTH WASHINGTON COAST. 1 PM TODAY TO 1 PM TUE FOR I-5 CORRIDOR IN COWLITZ CTY. 4 PM TODAY TO 1 PM TUE FOR GREATER VANCOUVER AREA PZ...NONE. && $$ MORE WEATHER INFORMATION ONLINE AT.. HTTP://WEATHER.GOV/PORTLAND INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
320 AM PST MON DEC 9 2013 .SYNOPSIS...ANOTHER VERY COLD NIGHT AS ARCTIC HIGH PRESSURE REMAINS DOMINANT OVER THE PACIFIC NORTHWEST. LOWER PRESSURE OFFSHORE CONTINUES TO DRIVE WEAK EASTERLY FLOW THROUGH THE COLUMBIA GORGE AND INTO THE PORTLAND AREA. A WEAK CLIPPER SYSTEM WILL PUSH DOWN FROM THE YUKON LATER TODAY...BRINGING A CHANCE OF SNOW AND OR FREEZING DRIZZLE MAINLY FOR OUR NORTHERN ZONES INTO TUESDAY. WEDNESDAY SHOULD REMAIN CHILLY AND DRY...THOUGH A LITTLE WARMER THAN THE PAST COUPLE DAYS AS OUR AIR MASS SLOWLY MODERATES. THE NEXT SYSTEM LOOKS STRONGER...AND MAY ENCOUNTER A STUBBORN LOW-LEVEL COLD AIR MASS AS PRECIPITATION SPREADS ONSHORE. THIS MAY RESULT IN MORE FROZEN OR FREEZING PRECIPITATION BEFORE A PACIFIC AIR MASS FINALLY TAKES OVER LATE IN THE WEEK. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY... ONE LAST BITTERLY COLD NIGHT OUT THERE TONIGHT BEFORE THE SLOW PROGRESSION OUT OF THE COLDSNAP BEGINS. SEEING SOME OF THAT WITH THE COAST REMAINING GENERAALLY IN THE 20S. IT IS A BALMY 3 DEGREES IN EUGENE AND PLENTY OF TEENS INLAND. TEMPS AND DEWPOINTS ARE UP A LITTLE FROM LAST NIGHT WHICH SHOULD PREVENT WIDESPREAD SINGLE DIGITS. LOWER CLOUDS ARE ROLLING INTO THE COAST THIS MORNING...AND KLGX RADAR DEPICTS SOME SHOWER ACTIVITY OFFSHORE THAT IS SOMEWHAT DYING OUT ON THE LEADING EDGE. LATEST HI-RES GUIDANCE SUGGESTS THAT NOT A WHOLE LOT OF INLAND PROGRESS THIS MORNING AS THE FLOW IS STILL MORE NORTHERLY ALOFT...BUT LIKELY SOME LIGHT SNOW OR FLURRIES FOR THE S WA/N OR COAST AND COAST RANGE. A SOMEWHAT CHALLENGING FORECAST COMING UP THE NEXT FEW DAYS AFTER THE NEAR TERM AS SEVERAL WEAK WAVES MOVE THROUGH BUT MIXED SIGNALS WITH REGARDS TO PRECIPITATION. COULD SEE SOME VERY LIGHT SNOW/FLURRIES OR SOME FREEZING DRIZZLE.AFTER THIS MORNING SEVERAL MODELS BRING LIGHT PRECIPITATION (0.02" QPF OR LESS) INTO THE INTERIOR THIS AFTERNOON. CURRENT KLGX DATA WOULD SUGGEST THAT PRECIPITATION WILL CONTINUE WORKING INLAND...BUT MAY HAVE PROBLEMS WITH THE DRY AIR MASS. MEANWHILE THE HRRR AND NAM KEEP PRECIPITATION CONFINED TO COAST AND COAST RANGE WHERE TEMPERATURE PROFILES BEGIN TO WARM GIVEN THE WEAK ONSHORE FLOW TO THE POINT WHERE PRECIP TYPE WOULD CHANGE TO RAIN OR MAYBE RAIN-SNOW MIX. MEANWHILE INLAND THE PROFILE WILL REMAIN ALL BELOW FREEZING. AFTER THAT THERE IS A MORE DISTINCT WAVE OFF THE COAST OF NORTHERN B.C. THAT WILL DROP S.E. AND PROVIDE A BIT MORE ORGANIZED LIFT TONIGHT INTO EARLY TUESDAY. THE MOISTURE LAYER LOOKS TO BE RATHER SHALLOW. THESE SITUATIONS TEND TO FAVOR FREEZING DRIZZLE...BUT ONLY IF YOU TAKE THEM FOR FACE VALUE AND DO NOT CONSIDER THE INITIAL AIRMASS THAT THE CLOUD FORMED IN OR THE AIRMASS THE SATURATED CLOUD IS MOVING INTO. SOUNDINGS SUGGEST THE TOP OF THE MOIST LAYER AROUND -5 TO -7C. IT IS INCORRECT TO SUGGEST THAT THERE WILL BE NO ICE CRYSTALS PRESENT IN THE CLOUD EVEN AT THESE TEMPERATURES...JUST A QUESTION OF IF THERE ARE ENOUGH. CANNOT IGNORE THE FACT THERE MAY ALSO BE SOME FREEZING DRIZZLE WHICH IF HITTING THE COLD ROADS WOULD FREEZE LIKE THE SNOW DID THE OTHER DAY. THAT SAID...AN INVESTIGATION OF DUAL-POLARIZATION DATA FROM KLGX AND SIMPLY DUE TO THE FACT THAT REFLECTIVITY RETURNS ARE AS HIGH AS 30-40 DBZ SUGGEST THAT P-TYPE...AT LEAST CURRENTLY AND WITH THE FIRST BATCH COMING IN IS SNOW AND NOT FREEZING DRIZZLE. THE 0Z QUILLAYUTE SOUNDING DOES SUGGEST A WARM LAYER ABOVE THE MOIST LAYER.. BUT THE POTENTIAL OF FREEZING DRIZZLE CANNOT BE IGNORED AS THE LOWER LEVEL PROFILE WARMS AND REDUCES ICE CRYSTAL AVAILABILITY ESPECIALLY TOWARDS TUESDAY. AND ANY ACCUMULATING FREEZING DRIZZLE WOULD WARRANT AN ADVISORY...ALSO DUE TO THE FACT DEWPOINTS WILL BE MUCH HIGHER MONDAY NIGHT INTO TUESDAY MORNING...ROADS HAVE THE POTENTIAL TO BE QUITE HAZARDOUS...REGARDLESS OF THE PRECIP TYPE OR HOW MUCH/HOW LITTLE SNOW ACTUALLY FALLS. SREF PLUMES KEEP ANYWHERE FROM LIGHT SNOW ACCUMS TO UP TO AN INCH IN THE METRO. MODELS CONTINUE TO FAVOR THE KELSO/CASTLE ROCK AREA AND THE I-5 CORRIDOR IN WASHINGTON FOR THE MOST QPF. THEREFORE SEE NO REASON AT LEAST AT THIS TIME TO CHANGE THE HEADLINE...BUT WILL FOCUS ON FREEZING DRIZZLE/SNOW POTENTIAL AND ROAD IMPACTS. SINCE THE CENTRAL VALLEY DOES NOT LOOK TO SEE MUCH SNOW...I CAN FORESEE A SITUATION WHERE IF FREEZING DRIZZLE DOMINATES AND THE PRECIP GETS A BIT FARTHER SOUTH...THAT AN ADVISORY WOULD BE WARRANTED...BUT CONFIDENCE IS LOW. DO STILL THINK THAT 1-2" ARE POSSIBLE IF THE P-TYPE REMAINS SNOW MAINLY NORTH OF THE COLUMBIA RIVER AND ALSO TOWARDS ST HELENS/SCAPPOOSE. I HOPE THIS DOES NOT COME BACK TO HAUNT ME...BUT AM CONTEMPLATING TO REMOVING THE CENTRAL WILLAMETTE VALLEY FROM THE WINTER WX ADVISORY...AS QPF IN THESE AREAS DOES NOT SUPPORT AT THAT MUCH IN THE WAY OF SNOW. IF FREEZING DRIZZLE IS THE MORE DOMINANT P-TYPE...THAN AN ADVISORY WOULD THEN BE WARRANTED. WILL WORK UP THE WSW HERE WITH REFINED TIMING AND FINAL DECISIONS SHORTLY AND SEND AN AMENDED AFD WITH THE HEADLINES. THE MAIN JET ENERGY COMING OUT OF WESTERN CANADA SHOULD SHIFT FARTHER EAST BY WEDNESDAY...ALLOWING SOME CLEARING AND POSSIBLY ANOTHER CLEAR CALM AND CHILLY MORNING FOR SOME AREAS WED MORNING. EXPECT THERE TO THEN BE FOG/FREEZING FOG. AFTER BURN OFF AND WITH SOME SUNSHINE AND A SOMEWHAT MODERATED AIR MASS...MOST AREAS SHOULD BE ABLE TO GET ABOVE FREEZING WEDNESDAY. HAVE DRIED OUT THE FORECAST FOR WEDS AND WEDNESDAY NIGHT WITH THE EXPECTED TREND OF BACKING OFF THE ARRIVAL OF THE PACIFIC SYSTEM WITH A COLD AND STRONG UPPER RIDGE IN PLACE. /KMD LEFT PREVIOUS DISCUSSION IN PLACE FOR THE LATTER PART OF THE SHORT TERM FROM THE EVENING SHIFT AS MUCH OF THIS SHIFT WAS SPENT FINE TUNING THE DETAILS THROUGH WEDNESDAY NIGHT.... NO DOUBT THIS IS AN HISTORIC COLD AIR MASS. WHICH BRINGS US TO OUR NEXT FORECAST CHALLENGE...THE PRECIPITATION TYPE EXPECTED FROM OUR NEXT EVENT. CONSIDERING THE MAGNITUDE OF COLD ASSOCIATED WITH THIS AIR MASS...IT IS VERY HARD TO BELIEVE WEAK CLIPPER SYSTEMS WILL BE SUFFICIENT TO ERODE THE COLD AIR ENTRENCHED OVER THE PACIFIC NORTHWEST. WE CONTINUE TO DISAGREE WITH MODEL GUIDANCE THAT SUGGESTS THE COLD AIR WILL SCOUR OUT QUICKLY...AND OUR TEMPERATURE AND PRECIPITATION TYPE FORECAST REFLECTS THAT ALL THE WAY INTO THURSDAY. WEAGLE .LONG TERM...NO CHANGES TO THE GRIDS OTHER THAN TO BACK OFF ON POPS A BIT TO START THURSDAY SO REST OF THE DISCUSSION REMAINS UNCHANGED...WILL LET THE DAY SHIFT REVISIT THE CHANGE IN TIMING AND IMPACTS ON THERMAL PROFILES...WEDNESDAY NIGHT THROUGH SUNDAY...OVERALL NO CHANGES TO THE THINKING BEHIND THE EXTENDED FORECAST. DID SOME MANIPULATION OF THE GRIDS TO ATTEMPT TO BETTER EXPRESS THE MIXED PRECIPITATION POTENTIAL WITH THE LATE WEEK SYSTEM. WEAGLE PREVIOUS DISCUSSION FOLLOWS...THE WELL ESTABLISHED COLD ARCTIC AIR MASS WILL BEGIN TO MODERATE AS FLOW ALOFT BECOMES MORE WESTERLY. TEMPERATURES LOOK TO TREND BACK TO SEASONAL NORMALS THROUGH THE SECOND HALF OF NEXT WEEK. THE 12Z GFS AND ECMWF ARE A BIT SLOWER TO BRING A SYSTEM ONSHORE EARLY THURSDAY SO HAVE ADJUSTED POP GRIDS TO REFLECT THIS. FORECAST MODELS BRING THE HEAVIEST PRECIP ONSHORE MIDDAY THURSDAY...WITH THE GFS SOLUTION ABOUT 6 HOURS FASTER. THERE REMAINS SOME CONCERN THAT THE MODELS ARE TOO QUICK TO WARM THE AIR MASS AFTER THIS PERIOD OF RECORD-SETTING COLD...SO IT IS POSSIBLE THAT THIS PRECIPITATION MAY BEGIN IN THE FORM OF SNOW OR FREEZING RAIN. THIS IS PARTICULARLY THE CASE FOR UPPER HOOD RIVER...THE COLUMBIA RIVER GORGE..AND THE NORTHERN WILLAMETTE VALLEY. OTHERWISE RAIN AND CASCADE SNOW IS EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT. THERE MAY BE A BRIEF DRY PERIOD AT LEAST PART OF THE DAY SATURDAY AS LOW LEVEL FLOW WILL TURN SOUTHERLY BEFORE THE THE NEXT SYSTEM ARRIVES SATURDAY AFTERNOON OR EVENING BRINGING RAIN ACROSS THE FORECAST AREA.CULLEN && .AVIATION...VFR CONDITIONS THIS AM...WITH POCKETS OF FOG IN S WILLAMETTE VALLEY. CLOUDS INCREASING ALONG OREGON COAST...AND SHOULD PERSIST THROUGH TUE AM. FLURRIES ON THE COAST THIS AM. CIGS ON S WASH/N ORE COAST WILL LOWER TO MVFR AFTER 16Z...WITH OCCASIONAL MVFR VIS WITH BURSTS OF SNOW. NOT MUCH CHANGE ON COAST FOR TONIGHT...BUT INLAND CIGS WILL DROP TO LOW VFR OR MVFR WITH MVFR VIS IN OCCASIONAL LIGHT SNOW ACROSS N TAF SITES. KPDX AND APPROACHES...VFR WITH LIGHT EAST WINDS CONTINUE. WILL HAVE INCREASING LOW VFR CLOUDS THIS AM...WITH SOME OCCASIONAL FLURRIES FROM 20Z THROUGH 06Z TUE. CIGS WILL LOWER TO MVFR AFTER 03Z...WITH INCREASING THREAT OF SNOW LATE OVERNIGHT INTO TUE AM. ROCKEY. .MARINE...BENIGN WEATHER THROUGH WED. HIGH PRES OVER PAC NW MAINTAINS LIGHT OFFSHORE FLOW THROUGH WED. WILL WILL TURN MORE W TO SW TUE AND WED AS HIGH WEAKENS AND LOWER PRES APPROACHES FROM THE W. SEAS HOLDING AT 2 TO 4 FT TODAY AND TUE...THEN BUILD SLIGHTLY LATER TUE AND WED. STRONG COLD FRONT WILL ARRIVE ON THU...WITH S GALES EXPECTED. SEAS WILL BUILD BACK CLOSER TO 10 FT. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...WEATHER WEATHER ADVISORY... 10 AM TODAY TO 10 AM TUE FOR LOWER COLUMBIA. 4 PM TODAY TO 4 PM TUE FOR NORTH WILLAMETTE VALLEY INCLUDING THE GREATER PORTLAND METRO AREA. 4 PM TODAY TO 4 PM TUE FOR CENTRAL WILLAMETTE VALLEY. WA...WINTER WEATHER ADVISORY... 7 AM TO 10 PM TODAY FOR SOUTH WASHINGTON COAST. 10 AM TODAY TO 10 AM TUE FOR I-5 CORRIDOR IN COWLITZ CTY. 4 PM TODAY TO 4 PM TUE FOR GREATER VANCOUVER AREA PZ...NONE. && $$ MORE WEATHER INFORMATION ONLINE AT.. HTTP://WEATHER.GOV/PORTLAND INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...UPDATED
NWS MIDLAND/ODESSA TX
912 AM CST Mon Dec 9 2013 .DISCUSSION... Have opted to issue a freezing fog advisory for most of the Basin including Lea County until 18z. Vsbys are being reported as low as 1/8 mile here at MAF and 1/4 mile at Andrews. Also, flurries are being reported in Midland/Greenwood/Snyder and have mentioned that in fcst too. && .PREV DISCUSSION... /ISSUED 734 AM CST Mon Dec 9 2013/ UPDATE... Have sent an update to include mention of Freezing fog across most of the PB and Lea Co. DISCUSSION... Cold air is pushing swd and areas of freezing fog are developing in the colder air. Big Spring and Snyder are down to 3/4 to 1 1/4 miles visibility. NAM12 is a little too cool and RUC13 a little too warm looking at dwpnts upstream IT will still take a few hrs for dwpnts to decrease and thus fog expected to hang around thru at least mid morning. Very light ice accumulations possible. PREV DISCUSSION... /ISSUED 506 AM CST Mon Dec 9 2013/ DISCUSSION... See aviation discussion below. AVIATION... Cold front currently moving southwest through the northern Permian Basin. Expecting prevailing to tempo MVFR to IFR conditions behind this front today. A period of VFR conditions is possible this afternoon at the terminals before MVFR and or IFR conditions return early this evening and continuing overnight. Generally northeast winds of 5 to 15 mph are expected through this evening. 12 PREV DISCUSSION... /ISSUED 355 AM CST Mon Dec 9 2013/ DISCUSSION... Another cold front is moving through the area early this morning bringing a resurgence of very cold air. We are not seeing any freezing fog so far either ahead of or behind the front, and despite mostly clear skies and low T/Td depressions, concern is dropping for a serious freezing fog threat. It is still possible for some patchy freezing fog to form especially near the leading edge of the front with the fog threat diminishing farther behind the front as drier air filters south. The small T/Td depressions could allow for some ice condensation to occur on exposed surfaces despite the lack of fog creating slick spots on local roads. Models have backed off snow chances in SE NM today and tonight likely due to limited moisture and a very positively tilted weak upper trough so have removed PoPs. We then see slightly warmer temps Tuesday and Wednesday before a weak front arrives Thursday. A more zonal upper air pattern will limit the amount of cold air. Shortly following this front will be an upper level low moving out of the southwestern states. This low will be weakening as it approaches the area and may even be an open trough by the time it arrives over west Texas, but there should be enough moisture and instability for precipitation to develop Thursday. The amount and extent of precipitation will depend greatly on the strength of the upper low...the stronger the low the more likely it is the precip will spread farther west...a weak low or trough will push moisture and most precip to the eastern CWA. For now the consensus seems to be that it will be an open trough and thus will keep precip chances to the eastern counties. Temperatures at this time indicate the p-type would be rain so there may not be any travel worries this time. Friday gets warmer before yet another front arrives Saturday. Hennig && .PRELIMINARY POINT TEMPS/POPS... ANDREWS TX 29 18 43 25 / 10 10 0 0 BIG SPRING TX 28 18 44 26 / 10 10 0 0 CARLSBAD NM 42 25 48 27 / 10 10 0 0 DRYDEN TX 51 27 49 30 / 0 0 0 0 FORT STOCKTON TX 46 22 50 29 / 0 10 0 0 GUADALUPE PASS TX 44 22 44 28 / 10 10 0 0 HOBBS NM 32 17 45 24 / 10 10 0 0 MARFA TX 53 22 50 26 / 0 10 0 0 MIDLAND INTL AIRPORT TX 32 18 44 25 / 10 10 0 0 ODESSA TX 32 19 45 26 / 10 10 0 0 WINK TX 39 22 47 25 / 10 10 0 0 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...FREEZING FOG ADVISORY until 11 AM MST this morning FOR THE FOLLOWING ZONES... Central Lea County...Northern Lea County...Southern Lea County. TX...FREEZING FOG ADVISORY until Noon CST today FOR THE FOLLOWING ZONES... Andrews...Borden...Dawson...Ector...Gaines... Glasscock...Howard...Martin...Midland...Mitchell...Scurry... Winkler. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
753 AM CST MON DEC 9 2013 .UPDATE... Expanded the Freezing Fog Advisory another row of counties. && .DISCUSSION... The fog continues to expand into the Concho Valley, so I have expanded the Freezing Fog Advisory to include Irion, Tom Green, Concho, Menard, and Schleicher counties. We will continue to monitor to progress of the fog. && .PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 9 2013/ UPDATE... To expand the Freezing Fog Advisory... DISCUSSION... Areas of freezing fog across the Big Country, Heartland and Northwest Hill country continue to expand to the south and west. Temperatures are below freezing across the entire area and given the expansion of the fog, I went ahead and expanded the advisory to include all of the Big Country and the northern Concho Valley. The freezing fog could approach areas farther south in the next few hours, including San Angelo, so I will continue to monitor trends and these counties may need to eventually be added. Otherwise, the rest of the forecast looks on track. Please see the aviation discussion below... AVIATION... Stratus/fog continues to expand through much of West Central Texas this morning resulting in IFR to LIFR conditions. KSOA is a bit more tricky, as the stratus to the south is struggling to expand northward. For now, I have indicated MVFR ceilings by 14z, and will continue to monitor. Some improvement in ceilings is forecast by late morning or early afternoon, with MVFR ceilings returning to most sites. Winds today will be from the north at 5 to 10 knots PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/ SHORT TERM... Today and Tonight A cold front is currently moving through the Big Country and should be approaching the Interstate 10 corridor shortly after sunrise. Winds behind the front will become north and increase to about 8 to 12 mph, with colder air slowly filtering into West Central Texas. In addition, areas of freezing fog are evident just to the east of our area, which has slowly been creeping west. I expect this freezing fog to expand to a Throckmorton, to Coleman, to Mason line in the next few hours. A freezing fog advisory is in effect for parts of the Heartland through 9 AM, and I will continue to monitor trends for the possibility of expanding it north into parts of the Big Country and south toward Mason county. The HRRR is also indicating some post frontal fog across parts of the Big Country, which will need to be monitored. Stratus should fill in this morning behind the front, with much of the area becoming overcast by mid morning. Given the expected cloud cover and cold air advection, I lowered high temperatures slightly. Highs will range from the upper 20s north of Interstate 20, to the mid 40s across the Interstate 10 corridor. Cloudy skies through much of the overnight period will not support ideal radiational cooling conditions, but given the cold airmass that will be filtering into the region, I went ahead and lowered low temperatures slightly. Tuesday morning low temperatures will generally be in the teens to lower 20s across all of West Central Texas. Daniels LONG TERM... Tuesday through Sunday As a fast moving shortwave trough moves through the Great Lakes region Tuesday night into Wednesday, a cold front will move into Texas, causing another brief cooling for Wednesday into Thursday. However, no precipitation is expected with the front. Lee troughing on Thursday will allow winds to quickly turn back to the south in our area, allowing temperatures to warm back up across the area Thursday and especially Friday. An upper level low initially off the coast of California on Monday will move across the Desert Southwest and into the Texas panhandle by Friday. As this low approaches, weak shortwaves will move across the area out ahead of it, interacting with moisture return and low level warm air advection, resulting in at least a slight chance for showers mainly Thursday afternoon and Thursday night, with some lingering showers moving out of the area on Friday. The upper level low will then move east towards the Mississippi Valley by Saturday, sending a cold front into the area. And while the cold front will slow the warming trend, the air mass behind the front will not be of arctic origin, so while we have gone cooler than the MOS guidance for Saturday and Sunday, temperatures should continue to trend closer to normal values through the weekend. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 26 18 39 27 42 / 10 5 0 0 0 San Angelo 35 19 44 26 46 / 10 5 0 0 0 Junction 46 22 47 24 52 / 10 10 5 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... FREEZING FOG ADVISORY until 10 AM CST this morning FOR THE FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Concho... Fisher...Haskell...Irion...Jones...Kimble...Mason...McCulloch... Menard...Nolan...Runnels...San Saba...Schleicher...Shackelford... Sterling...Taylor...Throckmorton...Tom Green. && $$ Reimer
AREA FORECAST DISCUSSION...UPDATE
NWS MIDLAND/ODESSA TX
734 AM CST Mon Dec 9 2013 .UPDATE... Have sent an update to include mention of Freezing fog across most of the PB and Lea Co. && .DISCUSSION... Cold air is pushing swd and areas of freezing fog are developing in the colder air. Big Spring and Snyder are down to 3/4 to 1 1/4 miles visibility. NAM12 is a little too cool and RUC13 a little too warm looking at dwpnts upstream IT will still take a few hrs for dwpnts to decrease and thus fog expected to hang around thru at least mid morning. Very light ice accumulations possible. && .PREV DISCUSSION... /ISSUED 506 AM CST Mon Dec 9 2013/ DISCUSSION... See aviation discussion below. AVIATION... Cold front currently moving southwest through the northern Permian Basin. Expecting prevailing to tempo MVFR to IFR conditions behind this front today. A period of VFR conditions is possible this afternoon at the terminals before MVFR and or IFR conditions return early this evening and continuing overnight. Generally northeast winds of 5 to 15 mph are expected through this evening. 12 PREV DISCUSSION... /ISSUED 355 AM CST Mon Dec 9 2013/ DISCUSSION... Another cold front is moving through the area early this morning bringing a resurgence of very cold air. We are not seeing any freezing fog so far either ahead of or behind the front, and despite mostly clear skies and low T/Td depressions, concern is dropping for a serious freezing fog threat. It is still possible for some patchy freezing fog to form especially near the leading edge of the front with the fog threat diminishing farther behind the front as drier air filters south. The small T/Td depressions could allow for some ice condensation to occur on exposed surfaces despite the lack of fog creating slick spots on local roads. Models have backed off snow chances in SE NM today and tonight likely due to limited moisture and a very positively tilted weak upper trough so have removed PoPs. We then see slightly warmer temps Tuesday and Wednesday before a weak front arrives Thursday. A more zonal upper air pattern will limit the amount of cold air. Shortly following this front will be an upper level low moving out of the southwestern states. This low will be weakening as it approaches the area and may even be an open trough by the time it arrives over west Texas, but there should be enough moisture and instability for precipitation to develop Thursday. The amount and extent of precipitation will depend greatly on the strength of the upper low...the stronger the low the more likely it is the precip will spread farther west...a weak low or trough will push moisture and most precip to the eastern CWA. For now the consensus seems to be that it will be an open trough and thus will keep precip chances to the eastern counties. Temperatures at this time indicate the p-type would be rain so there may not be any travel worries this time. Friday gets warmer before yet another front arrives Saturday. Hennig && .PRELIMINARY POINT TEMPS/POPS... ANDREWS TX 29 18 43 25 / 10 10 0 0 BIG SPRING TX 28 18 44 26 / 10 10 0 0 CARLSBAD NM 42 25 48 27 / 10 10 0 0 DRYDEN TX 51 27 49 30 / 0 0 0 0 FORT STOCKTON TX 46 22 50 29 / 0 10 0 0 GUADALUPE PASS TX 44 22 44 28 / 10 10 0 0 HOBBS NM 32 17 45 24 / 10 10 0 0 MARFA TX 53 22 50 26 / 0 10 0 0 MIDLAND INTL AIRPORT TX 32 18 44 25 / 10 10 0 0 ODESSA TX 32 19 45 26 / 10 10 0 0 WINK TX 39 22 47 25 / 10 10 0 0 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
554 AM CST MON DEC 9 2013 .UPDATE... To expand the Freezing Fog Advisory... && .DISCUSSION... Areas of freezing fog across the Big Country, Heartland and Northwest Hill country continue to expand to the south and west. Temperatures are below freezing across the entire area and given the expansion of the fog, I went ahead and expanded the advisory to include all of the Big Country and the northern Concho Valley. The freezing fog could approach areas farther south in the next few hours, including San Angelo, so I will continue to monitor trends and these counties may need to eventually be added. Otherwise, the rest of the forecast looks on track. Please see the aviation discussion below... && .AVIATION... Stratus/fog continues to expand through much of West Central Texas this morning resulting in IFR to LIFR conditions. KSOA is a bit more tricky, as the stratus to the south is struggling to expand northward. For now, I have indicated MVFR ceilings by 14z, and will continue to monitor. Some improvement in ceilings is forecast by late morning or early afternoon, with MVFR ceilings returning to most sites. Winds today will be from the north at 5 to 10 knots && .PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/ SHORT TERM... Today and Tonight A cold front is currently moving through the Big Country and should be approaching the Interstate 10 corridor shortly after sunrise. Winds behind the front will become north and increase to about 8 to 12 mph, with colder air slowly filtering into West Central Texas. In addition, areas of freezing fog are evident just to the east of our area, which has slowly been creeping west. I expect this freezing fog to expand to a Throckmorton, to Coleman, to Mason line in the next few hours. A freezing fog advisory is in effect for parts of the Heartland through 9 AM, and I will continue to monitor trends for the possibility of expanding it north into parts of the Big Country and south toward Mason county. The HRRR is also indicating some post frontal fog across parts of the Big Country, which will need to be monitored. Stratus should fill in this morning behind the front, with much of the area becoming overcast by mid morning. Given the expected cloud cover and cold air advection, I lowered high temperatures slightly. Highs will range from the upper 20s north of Interstate 20, to the mid 40s across the Interstate 10 corridor. Cloudy skies through much of the overnight period will not support ideal radiational cooling conditions, but given the cold airmass that will be filtering into the region, I went ahead and lowered low temperatures slightly. Tuesday morning low temperatures will generally be in the teens to lower 20s across all of West Central Texas. Daniels LONG TERM... Tuesday through Sunday As a fast moving shortwave trough moves through the Great Lakes region Tuesday night into Wednesday, a cold front will move into Texas, causing another brief cooling for Wednesday into Thursday. However, no precipitation is expected with the front. Lee troughing on Thursday will allow winds to quickly turn back to the south in our area, allowing temperatures to warm back up across the area Thursday and especially Friday. An upper level low initially off the coast of California on Monday will move across the Desert Southwest and into the Texas panhandle by Friday. As this low approaches, weak shortwaves will move across the area out ahead of it, interacting with moisture return and low level warm air advection, resulting in at least a slight chance for showers mainly Thursday afternoon and Thursday night, with some lingering showers moving out of the area on Friday. The upper level low will then move east towards the Mississippi Valley by Saturday, sending a cold front into the area. And while the cold front will slow the warming trend, the air mass behind the front will not be of arctic origin, so while we have gone cooler than the MOS guidance for Saturday and Sunday, temperatures should continue to trend closer to normal values through the weekend. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 18 39 27 42 24 / 5 0 0 0 5 San Angelo 19 44 26 46 26 / 5 0 0 0 5 Junction 22 47 24 52 29 / 10 5 0 0 10 && .SJT WATCHES/WARNINGS/ADVISORIES... FREEZING FOG ADVISORY until 10 AM CST this morning FOR THE FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Fisher... Haskell...Jones...Kimble...Mason...McCulloch...Nolan...Runnels... San Saba...Shackelford...Sterling...Taylor...Throckmorton. && $$ Daniels
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
542 AM CST MON DEC 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND POTENTIAL FOR MORE SNOW LATER TONIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3 SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE -25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL. FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW FALLING JUST AHEAD OF THE SHORTWAVE. A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z. WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE AHEAD AND ISSUED AN ADVISORY FOR THEM. THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR PRECIPITATION THROUGHOUT. SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT. ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH 850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING... SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA. NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND. JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10 APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20 PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY 00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO WEDNESDAY. FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND... THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT... TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 542 AM CST MON DEC 9 2013 VFR TO MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES TODAY. GUSTY WEST WINDS OF 14 TO 18 KTS WITH GUSTS AROUND 24KTS WILL LEAD TO SOME PATCHY BLOWING SNOW...POSSIBLY REDUCING VISIBILITIES TO AROUND 5SM AT TIMES. SOUTH/SOUTHWEST WINDS WILL INCREASE LATE TONIGHT AHEAD OF A WEAK SYSTEM APPROACHING FROM THE NORTHERN PLAINS. LOOK FOR WINDS TO INCREASE INTO THE 14 TO 18 KT RANGE AGAIN WITH GUSTS AROUND 25 KTS POSSIBLE. SOME PATCHY BLOWING SNOW MAY OCCUR AGAIN LATE TONIGHT AS THE WINDS INCREASE. LIGHT SNOW OR FLURRIES WILL MOVE ACROSS THE TAF SITES MAINLY AFTER 10Z TONIGHT. A BRIEF PERIOD OF MVFR OR POSSIBLY IFR CONDITIONS MAY OCCUR AS THE SNOW MOVES THROUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY FOR WIZ017-029. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
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...D-L LONG TERM....GIMMESTAD AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
603 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 /23Z MONDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. LATE-DAY...IFR CONDITIONS WILL CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON. WEST/NORTHWEST WINDS WILL BE LESS THAN 10 KT. TONIGHT...IFR IS FORECAST TO TRANSITION TO MVFR BEFORE THE NEXT ROUND OF PRECIPITATION SETTLES INTO THE REGION. NORTHWEST WINDS WILL BE LESS THAN 10 KT. TUESDAY...MVFR WILL QUICKLY TRANSITION INTO IFR AS SNOW SETTLES IN ACROSS THE TERMINALS. A PERIOD OF LIFR IS POSSIBLE IN SOME HEAVIER SNOW. SOME IMPROVEMENT, MVFR, CAN BE EXPECTED 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/KRUZDLO MARINE...DRAG/KRUZDLO
AREA FORECAST DISCUSSION
NWS MIAMI FL
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 71 82 70 82 / 10 20 20 30 FORT LAUDERDALE 72 82 71 82 / 10 40 30 30 MIAMI 72 82 72 83 / 10 40 30 30 NAPLES 67 81 67 82 / 0 20 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...13/SI AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
300 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 /TONIGHT/... ISSUED AT 148 PM EST MON DEC 9 2013 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 092100Z TAF ISSUANCE/... ISSUED AT 1220 PM EST MON DEC 9 2013 STRATUS HAS BROKEN UP A BIT FASTER THAN PREVIOUSLY THOUGHT THIS AFTERNOON. UPDATED TAFS TO REFLECT THAT. NO OTHER CHANGES. 18Z DISCUSSION FOLLOWS. MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW. STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS. FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL. SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT NORTHWEST WINDS EXPECTED OVERNIGHT. LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON. MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM 15-16Z CONTINUING INTO THE AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TUCEK NEAR TERM...TUCEK SHORT TERM...TUCEK LONG TERM....RYAN AVIATION...RYAN 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
255 PM EST MON DEC 9 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 /TONIGHT/... ISSUED AT 148 PM EST MON DEC 9 2013 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 MEASUREABLE 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 091800Z TAF ISSUANCE/... ISSUED AT 1220 PM EST MON DEC 9 2013 MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW. STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS. FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL. SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT NORTHWEST WINDS EXPECTED OVERNIGHT. LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON. MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM 15-16Z CONTINUING INTO THE AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TUCEK NEAR TERM...TUCEK SHORT TERM...TUCEK LONG TERM....RYAN AVIATION...RYAN 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
223 PM EST MON DEC 9 2013 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE 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 /TONIGHT/... ISSUED AT 148 PM EST MON DEC 9 2013 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 MEASUREABLE 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 THROUGH SUNDAY/... ISSUED AT 333 AM EST MON DEC 9 2013 MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND TEMPERATURES THURSDAY AND FRIDAY. MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY. IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO ALL BLEND TEMPERATURES. && .AVIATION /DISCUSSION FOR 091800Z TAF ISSUANCE/... ISSUED AT 1220 PM EST MON DEC 9 2013 MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW. STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS. FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL. SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT NORTHWEST WINDS EXPECTED OVERNIGHT. LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON. MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM 15-16Z CONTINUING INTO THE AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TUCEK NEAR TERM...TUCEK SHORT TERM...TUCEK LONG TERM....JH AVIATION...RYAN 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
1226 PM EST MON DEC 9 2013 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 337 AM EST MON DEC 9 2013 HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY. TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 1221 PM EST MON DEC 9 2013 LOOKS LIKE BANDED LOW LEVEL CLOUDS THAT HAVE BEEN PRODUCING LIGHT SNOW SHOWERS HAS DIMINISHED OVER CENTRAL INDIANA AND CURRENTLY CONFINED TO NORTHERN INDIANA NE IL SO WILL END MENTION OF FLURRIES HERE. SOME BREAKS IN CLOUDS AND BRIGHTENING OF SKY EXPECTED BUT OVERALL MOSTLY CLOUDY WORDING STILL WORKS AND DESPITE BRIGHTER SKIES...STRENGTH OF COLD ACROSS ILLINOIS SUGGESTS NO REAL WARMING TO OCCUR. HAVE BUMPED WIND SPEEDS UP A TAD TO MATCH CURRENT OBS. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 337 AM EST MON DEC 9 2013 FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST PERIODS. TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN 2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL. NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH. WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME AREAS ACROSS THE SOUTH. FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM APPROACHES. AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL WEDNESDAY NIGHT AS SYSTEM EXITS. LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 333 AM EST MON DEC 9 2013 MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND TEMPERATURES THURSDAY AND FRIDAY. MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY. IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO ALL BLEND TEMPERATURES. && .AVIATION /DISCUSSION FOR 091800Z TAF ISSUANCE/... ISSUED AT 1220 PM EST MON DEC 9 2013 MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW. STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS. FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL. SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT NORTHWEST WINDS EXPECTED OVERNIGHT. LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON. MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM 15-16Z CONTINUING INTO THE AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...50 NEAR TERM...TUCEK SHORT TERM...50 LONG TERM....JH AVIATION...RYAN 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
1220 PM EST MON DEC 9 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 337 AM EST MON DEC 9 2013 HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY. TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /TODAY/... ISSUED AT 919 AM EST MON DEC 9 2013 INTRODUCING FLURRIES INTO FORECAST THROUGH MID AFTERNOON GIVEN WEAK RADAR RETURNS COUPLED WITH SURFACE OBSERVED LIGHT SNOW OCCURRING. DO NOT EXPECT ACCUMULATION THOUGH GIVEN NO VSBY DROP ACCOMPANYING CURRENT SNOW AND FLAKES QUITE SMALL. CLEARING ACROSS WC AND NW IL SHOULD WORK ITS WAY INTO WESTERN COUNTIES BY LATE AFTERNOON AS HIGH PRESSURE BUILDS IN BUT RETURN OF HIGH CLOUDS FROM SOUTHERN SYSTEMS APPROACH TO RETURN HIGHER DECKS BY NIGHTFALL. TEMPS TO HOLD FAIRLY STEADY THROUGH THE DAY GIVEN CLOUD DECK HOLDING AND COLD ADVECTION BEGINNING TO TAKE PLACE. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 337 AM EST MON DEC 9 2013 FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST PERIODS. TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN 2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL. NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH. WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME AREAS ACROSS THE SOUTH. FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM APPROACHES. AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL WEDNESDAY NIGHT AS SYSTEM EXITS. LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 333 AM EST MON DEC 9 2013 MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND TEMPERATURES THURSDAY AND FRIDAY. MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY. IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO ALL BLEND TEMPERATURES. && .AVIATION /DISCUSSION FOR 091800Z TAF ISSUANCE/... ISSUED AT 1220 PM EST MON DEC 9 2013 MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW. STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS. FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL. SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT NORTHWEST WINDS EXPECTED OVERNIGHT. LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON. MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM 15-16Z CONTINUING INTO THE AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...50 NEAR TERM...TUCEK SHORT TERM...50 LONG TERM....JH AVIATION...RYAN 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
435 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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 205 PM EST MON DEC 9 2013 ALTHOUGH DRIER AIR IS FILTERING INTO THE AREA CIGS ARE STILL QUITE LOW. HAVE LIMITED THEIR RECOVER TO LATE THIS AFTERNOON AND EARLY THIS EVENING. CONFIDENCE IN THE DETAILS OF SNOW DEVELOPING ACROSS THE AREA OVERNIGHT HAS INCREASED WITH BETTER MODEL AGREEMENT. ACCORDINGLY...HAVE HIT ALL THE TAFS WITH A PERIOD OF SNOW...LOW CIGS...AND VIS FROM SOMETIME AFTER MIDNIGHT UNTIL JUST AFTER DAWN ON TUESDAY. EXPECT CONDITIONS TO IMPROVE BUT CIGS WILL PROBABLY BE MVFR INTO THE FIRST PART OF THE AFTERNOON. 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. && .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...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 117 PM EST MON DEC 9 2013 KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THIS AFTERNOON. CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW. MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF NEXT DISTURBANCE THE NOTRHERN PLAINS. KCMX...IFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO HEAVY LAKE EFFECT SNOW THIS AFTERNOON AS WSW WINDS VEER TO THE W AND BECOME GUSTY. THIS WILL CONTINUE INTO THE EVENING HOURS BUT SHOULD IMPROVE BY LATE EVENING. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE TONIGHT AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. KSAW...MVFR CIGS THIS AFTERNOON ARE EXPECTED THAT WILL LIFT BACK TO VFR AS A DISTUBANCE MOVES TO THE EAST OF THE AREA. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD OF MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES. && .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 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247. GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
417 PM EST MON DEC 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 551 AM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT TERM. ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE DIMINISHING. TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850 MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING SNOW/LOCALIZED WHITEOUT CONDITONS IN WSW STATEMENT UNDER THE DOMINANT BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG BUILDING IN FM THE WEST. THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF 25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO. .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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 117 PM EST MON DEC 9 2013 KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THIS AFTERNOON. CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW. MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF NEXT DISTURBANCE THE NOTRHERN PLAINS. KCMX...IFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO HEAVY LAKE EFFECT SNOW THIS AFTERNOON AS WSW WINDS VEER TO THE W AND BECOME GUSTY. THIS WILL CONTINUE INTO THE EVENING HOURS BUT SHOULD IMPROVE BY LATE EVENING. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE TONIGHT AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. KSAW...MVFR CIGS THIS AFTERNOON ARE EXPECTED THAT WILL LIFT BACK TO VFR AS A DISTUBANCE MOVES TO THE EAST OF THE AREA. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD OF MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 551 AM 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 WILL PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR 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 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247. GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...VOSS LONG TERM...SRF AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
118 PM EST MON DEC 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 551 AM EST MON DEC 9 2013 WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT TERM. ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE DIMINISHING. TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850 MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING SNOW/LOCALIZED WHITEOUT CONDITONS IN WSW STATEMENT UNDER THE DOMINANT BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG BUILDING IN FM THE WEST. THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF 25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 519 AM EST MON DEC 9 2013 CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED. ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE REINFORCING SHOTS THROUGH THIS WEEKEND. TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS. EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F. LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8 INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH ATTM. A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR THE COLDEST LOCATIONS. THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY. COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 117 PM EST MON DEC 9 2013 KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THIS AFTERNOON. CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW. MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF NEXT DISTURBANCE THE NOTRHERN PLAINS. KCMX...IFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO HEAVY LAKE EFFECT SNOW THIS AFTERNOON AS WSW WINDS VEER TO THE W AND BECOME GUSTY. THIS WILL CONTINUE INTO THE EVENING HOURS BUT SHOULD IMPROVE BY LATE EVENING. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE TONIGHT AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA. KSAW...MVFR CIGS THIS AFTERNOON ARE EXPECTED THAT WILL LIFT BACK TO VFR AS A DISTUBANCE MOVES TO THE EAST OF THE AREA. THE NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER PERIOD OF MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 551 AM EST MON DEC 9 2013(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 FOR GALES. THE FIRST TROUGH WILL PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS LAKE SUPERIOR 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 SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ245-248>251-265>267. GALE WARNING UNTIL 5 AM EST TUESDAY FOR LSZ244-245-265>267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264. GALE WARNING UNTIL 5 AM EST TUESDAY FOR LSZ264. GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247. GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263. LAKE MICHIGAN... GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...VOSS LONG TERM...KLUBER AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1244 PM MST MON DEC 9 2013 .UPDATE... MAKING ANOTHER QUICK UPDATE THIS MORNING TO ACCOUNT FOR THE EXPIRATION OF THE WIND CHILL ADVISORY THAT IS REPLACED WITH A WINTER WEATHER ADVISORY. OTHERWISE...THE GOING FORECAST APPEARS TO BE IN GOOD SHAPE. AAG && .SHORT TERM...VALID FOR TDY AND TUE... WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH. TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55 MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY 21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE 70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA. NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/. WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00 UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED IN TIME WITH A LATER FORECAST RELEASE. TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F /MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING. TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE. THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO BE FAIRLY MOIST. TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE WESTERN ZONES. BORSUM && .AVIATION... QUICK UPDATE FOR AVIATION CONDITIONS THIS AFTERNOON...A BAND OF FAIRLY HEAVY SNOWFALL HAS CAUSED VISIBILITIES TO DETERIORATE RAPIDLY AT KMLS AND KBHK. THIS COMBINED WITH VERY GUSTY WINDS AND PREVIOUS SNOWFALL ON THE GROUND...WILL BRING WITH IT IFR CONDITIONS. THE SNOW SHOWERS SHOULD END IN THE NEXT FEW HOURS... BUT THE GUSTY WINDS WILL PERSIST INTO THE EVENING. SINGER && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 019 014/023 005/029 020/033 018/034 015/034 024/036 1/Q 16/S 51/B 11/B 11/B 11/B 11/B LVM 016 010/022 007/026 020/032 021/034 019/032 024/033 2/J 24/S 42/J 11/N 12/J 11/B 11/N HDN 022 012/022 901/027 014/035 015/032 012/032 022/036 2/J 28/S 51/B 11/B 11/E 11/B 12/B MLS 020 009/016 907/023 010/031 013/026 010/028 020/035 9/J 38/S 21/B 11/B 12/J 11/B 22/B 4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036 8/J 47/S 21/B 00/B 01/B 11/B 22/B BHK 016 009/013 910/017 009/029 012/022 010/027 018/033 9/J 56/S 11/B 01/B 11/B 11/E 12/B SHR 023 008/024 901/027 014/036 016/034 014/033 022/038 2/J 25/S 51/B 01/B 12/J 11/B 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR ZONES 28-29-34-35-39-41-42-56-63-65-66. WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS EVENING FOR ZONES 30>33-36>38-57-58. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1127 AM MST MON DEC 9 2013 .UPDATE... MAKING ANOTHER QUICK UPDATE THIS MORNING TO ACCOUNT FOR THE EXPIRATION OF THE WIND CHILL ADVISORY THAT IS REPLACED WITH A WINTER WEATHER ADVISORY. OTHERWISE...THE GOING FORECAST APPEARS TO BE IN GOOD SHAPE. AAG && .SHORT TERM...VALID FOR TDY AND TUE... WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH. TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55 MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY 21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE 70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA. NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/. WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00 UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED IN TIME WITH A LATER FORECAST RELEASE. TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F /MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING. TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE. THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO BE FAIRLY MOIST. TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE WESTERN ZONES. BORSUM && .AVIATION... FAST MOVING COLD FRONT WILL MOVE THROUGH EASTERN AND CENTRAL MONTANA BRINGING INCREASED WINDS...BLOWING SNOW AND SNOW SHOWERS. BEST CHANCE FOR SNOW WILL BE FOR EASTERN MONTANA WITH BLOWING SNOW BEING THE BIGGEST PROBLEM FOR KBIL AND KLVM. VERY STRONG WINDS ARE POSSIBLE FOR KLVM WITH DRIFTING AND BLOWING SNOW CREATING IFR CONDITIONS AT TIMES. KBIL WILL SEE WINDS GUSTS TO 45 MPH WITH MVFR CONDITIONS DUE TO BLOWING SNOW. KMLS WILL SEE LOWER CEILINGS IN THE SNOW SHOWERS WITH IFR CONDITIONS AT TIMES. KSHR WILL SEE CONDITIONS STAY MOSTLY VFR BUT WILL APPROACH MVFR CONDITIONS LATER IN THE AFTERNOON. BORSUM && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 019 014/023 005/029 020/033 018/034 015/034 024/036 1/Q 16/S 51/B 11/B 11/B 11/B 11/B LVM 016 010/022 007/026 020/032 021/034 019/032 024/033 2/J 24/S 42/J 11/N 12/J 11/B 11/N HDN 022 012/022 901/027 014/035 015/032 012/032 022/036 2/J 28/S 51/B 11/B 11/E 11/B 12/B MLS 020 009/016 907/023 010/031 013/026 010/028 020/035 9/J 38/S 21/B 11/B 12/J 11/B 22/B 4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036 8/J 47/S 21/B 00/B 01/B 11/B 22/B BHK 016 009/013 910/017 009/029 012/022 010/027 018/033 9/J 56/S 11/B 01/B 11/B 11/E 12/B SHR 023 008/024 901/027 014/036 016/034 014/033 022/038 2/J 25/S 51/B 01/B 12/J 11/B 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR ZONES 28-29-34-35-39-41-42-56-63-65-66. WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS EVENING FOR ZONES 30>33-36>38-57-58. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
916 AM MST MON DEC 9 2013 .UPDATE... NO CHANGES MADE TO INHERITED FORECAST. THE SHORT TERM FORECAST APPEARS IN GOOD SHAPE...WITH STRONG AND GUSTY WINDS IMPACTING AREAS FROM BILLINGS TO THE WEST. STRONGEST WINDS ARE IN BIG TIMBER AND LIVINGSTON...WHERE GUSTS ARE APPROACHING 60 MPH AND ARE EXPECTED TO INCREASE INTO THIS AFTERNOON. VISIBILITIES HAVE BEEN REDUCED TO LESS THAN A QUARTER MILE IN BIG TIMBER AND TO AROUND 1 MILE IN LIVINGSTON...WITH LOCALIZED WHITE OUT CONDITIONS. THESE LOCALIZED WHITE OUT CONDITIONS ARE EXPECTED TO CONTINUE THROUGH TODAY...AND POSSIBLY INTO TONIGHT. ADDITIONALLY...SLIDE OFFS HAVE BEEN REPORTED IN SEVERAL LOCATIONS INCLUDING MUSSELSHELL...STILLWATER...AND SWEET GRASS COUNTIES. BLOWING AND DRIFTING SNOW MAY HAVE BEEN A CONTRIBUTING FACTOR IN CONJUNCTION WITH ALREADY ICY ROADWAYS. AAG && .SHORT TERM...VALID FOR TDY AND TUE... WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH. TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55 MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY 21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE 70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA. NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/. WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00 UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED IN TIME WITH A LATER FORECAST RELEASE. TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F /MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING. TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE. THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO BE FAIRLY MOIST. TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE WESTERN ZONES. BORSUM && .AVIATION... FAST MOVING COLD FRONT WILL MOVE THROUGH EASTERN AND CENTRAL MONTANA BRINGING INCREASED WINDS...BLOWING SNOW AND SNOW SHOWERS. BEST CHANCE FOR SNOW WILL BE FOR EASTERN MONTANA WITH BLOWING SNOW BEING THE BIGGEST PROBLEM FOR KBIL AND KLVM. VERY STRONG WINDS ARE POSSIBLE FOR KLVM WITH DRIFTING AND BLOWING SNOW CREATING IFR CONDITIONS AT TIMES. KBIL WILL SEE WINDS GUSTS TO 45 MPH WITH MVFR CONDITIONS DUE TO BLOWING SNOW. KMLS WILL SEE LOWER CEILINGS IN THE SNOW SHOWERS WITH IFR CONDITIONS AT TIMES. KSHR WILL SEE CONDITIONS STAY MOSTLY VFR BUT WILL APPROACH MVFR CONDITIONS LATER IN THE AFTERNOON. BORSUM && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 019 014/023 005/029 020/033 018/034 015/034 024/036 1/Q 16/S 51/B 11/B 11/B 11/B 11/B LVM 016 010/022 007/026 020/032 021/034 019/032 024/033 2/J 24/S 42/J 11/N 12/J 11/B 11/N HDN 022 012/022 901/027 014/035 015/032 012/032 022/036 2/J 28/S 51/B 11/B 11/E 11/B 12/B MLS 020 009/016 907/023 010/031 013/026 010/028 020/035 9/J 38/S 21/B 11/B 12/J 11/B 22/B 4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036 8/J 47/S 21/B 00/B 01/B 11/B 22/B BHK 016 009/013 910/017 009/029 012/022 010/027 018/033 9/J 56/S 11/B 01/B 11/B 11/E 12/B SHR 023 008/024 901/027 014/036 016/034 014/033 022/038 2/J 25/S 51/B 01/B 12/J 11/B 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR ZONES 28-29-34-35-39-41-42-56-63-65-66. WIND CHILL ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR ZONES 30>33-36>38-57-58. WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS EVENING FOR ZONES 30>33-36>38-57-58. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1250 PM EST MON DEC 9 2013 .SYNOPSIS... A SLOW-MOVING FRONTAL SYSTEM WEST OF THE APPALACHIANS THIS MORNING WILL DRIFT ACROSS OUR REGION TONIGHT AND TUESDAY. CHILLY HIGH PRESSURE WILL BUILD INTO OUR REGION TUESDAY NIGHT AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM MONDAY... NOT A LOT OF CHANGE NEEDED TO THE FORECAST THIS MORNING. THE CAD AIRMASS IS FAIRLY WELL ENTRENCHED AND WILL STRUGGLE TO ERODE TODAY. WHILE THE DEPTH OF THE RESIDUAL COLD POOL HAS DECREASED ON THE 12Z KGSO RAOB...THERE IS STILL A UNIFORM 40KT FLOW AT 850MB AND ENOUGH WARM ADVECTION TO KEEP STATIC STABILITY STRONG AND THE CAD LOCKED IN. RAP AND HRR SOUNDINGS KEEP THE ENTIRE CWA MURKY WELL ON INTO TONIGHT. THE CURRENT TEMP FORECAST IS AT THE LOWEST END OF THE GUIDANCE SPECTRUM...SHOWING TEMPS RANGING FROM LOWER 40S TO UPPER 50S. THE BIGGEST POTENTIAL FOR ERROR WILL BE BETWEEN THE TRIANGLE AND THE COASTAL PLAIN AS THE CAD BOUNDARY TRIES TO RETREAT NORTH AND WESTWARD. REGARDING POPS...THE AXIS OF DEEPEST MOISTURE IS CURRENTLY OVER WESTERN NC...AHEAD OF THE SLOW MOVING COLD FRONT WEST OF THE MOUNTAINS. THE NARROW RAIN BAND THAT CURRENTLY EXTENDS FROM WEST OF KCLT TO KGSO AND AND INTO VA APPEARS TO BE LINKED TO ISENTROPIC LIFT BETWEEN 295K AND 305K...WHICH WEAKENS THIS AFTERNOON AS ANOTHER WAVE OF LOW PRESSURE BEGINS TO FORM TO OUR SOUTHWEST ALONG THE FRONT. EVEN IF A LULL DEVELOPS...DRIZZLE WILL CONTINUE...SO HIGH POPS WILL BE MAINTAINED....PARTICULARLY WEST OF HWY 1. -SMITH TONIGHT: S/W ENERGY OVER THE CENTRAL ROCKIES WILL PUSH EASTWARD TODAY INTO TONIGHT... HELPING TO PUSH A COLD FRONT EASTWARD TOWARDS OUR REGION... WITH A SURFACE LOW DEVELOPING ALONG THE WEDGE FRONT (AHEAD OF THE APPROACHING COLD FRONT) SOMEWHERE ACROSS OUR SOUTHEAST/JUST TO THE SOUTH OF OUR REGION LATE TONIGHT. THIS SURFACE LOW AND CONTINUED MID LEVEL S/W ENERGY EMBEDDED IN THE SOUTHWESTERLY MID LEVEL FLOW WILL HELP SUPPORT A GOOD CHANCE OF RAIN AREAWIDE. TEMPS MAY ACTUALLY RISE OR HOLD STEADY OVERNIGHT WHERE THE CAD HOLDS TODAY. WILL GO WITH LOWS RANGING FROM THE LOW TO MID 40S NW TO LOW TO MID 50S SE. -BSD && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM MONDAY... TUESDAY...THE SURFACE LOW THAT DEVELOPS ALONG A FRONT SITUATED SW-NE ACROSS CENTRAL NC WILL AID TO ENHANCE LOW LEVEL CONVERGENCE OVER OUR REGION. ALOFT...A STRONG JET STREAKING ACROSS THE EASTERN LAKES INTO SOUTHERN NEW ENGLAND WILL INCREASE UPPER LEVEL DIVERGENCE OVER THE VIRGINIAS AND NC WHILE THE MID LEVEL S/W RESPONSIBLE FOR GENERATING THE SURFACE WAVE OVERHEAD WILL QUICKLY SHEAR NEWD ACROSS THE TN AND MID OH VALLEY. THE COMBINATION OF THE AVAILABLE LIFT AND MOISTURE SUGGEST RAIN SHOULD BE WIDESPREAD ACROSS THE REGION TO START THE DAY TUESDAY. MODEL GUIDANCE HAS VARIED AS TO WHERE THE AXIS OF "HEAVIEST" PRECIP (A QUARTER TO A HALF INCH) WILL SET-UP. HOWEVER...00Z GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT...FAVORING THE EASTERN PIEDMONT AND COASTAL PLAIN. STILL...BETTER DYNAMICS ALOFT WILL RESIDE OVER THE NW PIEDMONT. AT THIS TIME PLAN TO BROADBRUSH THE PRECIP AMOUNTS ACROSS THE REGION WITH TWO TO THREE TENTHS EXPECTED IN THE 12Z-18Z TUESDAY TIME FRAME. MID LEVEL S/W WILL QUICKLY SHEAR OUT TO THE NE TUESDAY AFTERNOON...PROPELLING THE SURFACE FRONT EASTWARD TO THE COAST BY TUESDAY AFTERNOON. THUS...SHOULD SEE PRECIP TAPER OFF WEST-TO-EAST TUESDAY AFTERNOON ACROSS CENTRAL NC. DEVELOPING NW FLOW IN THE LOWER LEVELS WILL LEAD TO DECREASING CLOUDINESS LATE IN THE DAY. DEVELOPING DOWNSLOPE FLOW WILL INITIALLY OFFSET COLD AIR ADVECTION. RESIDUAL CAD AIR MASS ACROSS THE NORTH-NW PIEDMONT SHOULD HOLD TEMPS IN THE 40S. EXPECT WARMER TEMPS OVER THE SOUTHERN COUNTIES WHERE TEMPS IN THE 50S (AROUND 60 FAR SE) PROBABLE. COLDER DRIER AIR WILL OVERSPREAD CENTRAL NC TUESDAY NIGHT AS A MODIFIED CANADIAN HIGH PRESSURE SYSTEM BUILDS INTO THE REGION. PARENT HIGH EXPECTED TO BE CENTERED OVER THE CENTRAL APPALACHIANS BY EARLY WEDNESDAY WITH A SURFACE RIDGE EXTENDING INTO NC. THUS...WHILE EARLY TUESDAY EVENING WILL BE A BIT BREEZY...LOOKS PLAUSIBLE FOR SFC WINDS TO DECOUPLE AFTER MIDNIGHT. THIS WILL ALLOW TEMPS TO FALL INTO THE 20S BY DAYBREAK WEDNESDAY ACROSS THE NORTH...AND NEAR 30 ACROSS THE SOUTH. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 330 AM MONDAY... WEDNESDAY THROUGH FRIDAY...RELATIVELY TRANQUIL WEATHER PERIOD ANTICIPATED FROM MID WEEK TO THE END OF THE WEEK AS BROAD UPPER TROUGH COVERS THE EASTERN TWO-THIRDS OF THE NATION. THE NORTHERN BRANCH WILL BE DOMINATE IN THE BEGINNING...KEEPING THE STORM TRACK MAINLY ACROSS THE NORTHERN PLAINS-GREAT LAKES AND NEW ENGLAND. THE SURFACE HIGH THAT COVERS OUR REGION WEDNESDAY WILL QUICKLY SCOOT EWD BY LATE WEDNESDAY BUT IS REPLACED BY ANOTHER CHILLY HIGH THAT BUILDS INTO THE MID ATLANTIC IN THE WAKE OF A MID LEVEL S/W CROSSES THE GREAT LAKES INTO NEW ENGLAND. THUS OUR CURRENT STRETCH OF BE LOW NORMAL TEMPS WILL CONTINUE. HIGH TEMPS WED AND THU WILL BE IN THE 40S WHILE MIN TEMPS WILL BE IN THE 20S TO AROUND 30. SATURDAY INTO SUNDAY...OPERATIONAL GFS AND ECMWF OFFER A SIMILAR SOLUTION FOR THE UPCOMING WEEKEND WEATHER PATTERN...IN SHARP CONTRAST TOT E 12Z MODEL RUNS WHICH DEPICTED A SOLUTION VERY SIMILAR TO OUR CURRENT WEATHER PATTERN. MODEL GUIDANCE NOW ADVERTISING A RETURN FLOW REGIME BECOMING ESTABLISHED FRIDAY NIGHT INTO SATURDAY...AHEAD OF A FRONTAL SYSTEM DOMINATED BY A S/W IN THE NORTHERN STREAM. THIS FRONTAL SYSTEM CROSSES OUR REGION SATURDAY NIGHT WITH CHILLY HIGH PRESSURE BUILDING INTO OUR REGION SUNDAY. FOR NOW WILL CONFINE THE BEST CHANCE FOR PRECIP TO SATURDAY AND KEEP IT ALL LIQUID. IF PRECIP COMES INTO THE REGION EARLY ENOUGH FRIDAY NIGHT...MAY START OUT AS A WINTRY MIX BEFORE QUICKLY TRANSITIONING TO ALL RAIN. TEMPS EXPECTED TO REMAIN BELOW NORMAL AND HIGHLY DEPENDENT UPON PRECIP COVERAGE. HIGHS IN THE 40S TO AROUND 50. LOWS TEMPS IN THE 30S FRIDAY NIGHT AND 30S TO AROUND 40 SATURDAY NIGHT. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... AS OF 1250 PM MONDAY... WITH A PERSISTENT MOIST SOUTHWESTERLY FLOW IN PLACE...LOW CLOUDS CONTINUE TO CAUSE LIFR CONDITIONS THIS AFTERNOON WITH POCKETS OF RAIN...DRIZZLE AND LOW VSBYS. THERE IS HIGH CONFIDENCE THAT AT LEAST IFR CONDITIONS WILL CONTINUE...AND IT IS VERY POSSIBLE THAT LIFR CONDITIONS MAY PERSIST THROUGH THE NIGHT. A COLD FRONT WILL SLIP INTO NC FROM THE NORTH-NORTHWESTER LATE TONIGHT...WITH WINDS TURNING TO NORTHERLY BEHIND THE FRONT. MEANWHILE...A 40-50KT LOW LEVEL JET WILL SURGE BACK ACROSS THE AREA..CAUSING PRECIP TO CONTINUE BEHIND THE FRONT. IMPROVEMENT IN CEILINGS AND VSBYS WONT BEGIN UNTIL AFTER AROUND 18Z TUESDAY OR THEREAFTER. LOW LEVEL WIND SHEAR SHOULD DIMINISH THIS EVENING AS WINDS ABOVE THE SURFACE RELAX...BUT WILL REDEVELOP TONIGHT WITH THE ARRIVAL OF THE LOW-LEVEL JET ATOP WEAK SURFACE WINDS. LOOKING AHEAD: VFR CONDITIONS WILL RETURN TUE NIGHT AS DRY HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST. VFR/DRY CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE WORK WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...BSD/SMITH SHORT TERM...WSS LONG TERM...WSS AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
128 PM CST MON DEC 9 2013 .UPDATE... ISSUED AT 121 PM CST MON DEC 9 2013 BLIZZARD WARNING AND WINTER WEATHER ADVISORIES WILL BE IN EFFECT AT 3 PM CST THIS AFTERNOON. WAITING FOR THE SUBSIDENCE TO SWEEP ACROSS THE REGION AND CREATE BLOWING SNOW. SATELLITE PICTURES DEPICT THIS SUBSIDENCE FROM SASKATCHEWAN INTO NORTHEAST MONTANA. THE CENTER OF LOW PRESSURE NOW CLOSE TO THE NORTHWEST CORNER OF ND. THE LOW WILL TRACK SOUTHEAST TO NEAR MAX BY 5 PM BASED ON 18Z RUC THEN TO NORTHERN STUTSMAN COUNTY BY 7 PM CST. THIS WILL PUT THE WEST CENTRAL AND SOUTHWEST IN THE STRONG PRESSURE GRADIENT WITH ADDED PRESSURE RISE TO RAISE WIND GUSTS. CANCELLED THE WIND CHILL ADVISORY FOR THE AFTERNOON. THOUGH THE WIND CHILLS WOULD REMAIN COOLER FOR A FEW HOURS BUT THEY ARE NOW MOVING ABOVE -25 MOST AREAS. UPDATE ISSUED AT 1047 AM CST MON DEC 9 2013 WILL UPGRADE THE ADVISORY TO A BLIZZARD WARNING FOR THE WEST CENTRAL...SOUTHWEST AND FAR SOUTH CENTRAL. ALSO ADDING ANOTHER TIER OF COUNTIES INTO THE WINTER WEATHER ADVISORY...INCLUDING EMMONS BURLEIGH AND SHERIDAN. EXAMINED MODEL SOUNDINGS AND SEE STRONG POTENTIAL FOR 45 MPH WIND GUSTS WITH THE ALBERTA CLIPPER ACROSS THE SOUTHWEST. ALSO...SUPERSATURATED WITH RESPECT TO ICE IN THE DENDRITIC GROWTH ZONE FROM THE BOUNDARY LAYER TO 700 MB. WITH THAT IN MINE SEE POTENTIAL TO GENERATE A BURST OF SNOWFALL WITH THE SYSTEM. NOT MUCH MORE THAN 1 TO 2 INCHES BUT ADDING THE SNOW TO THE WINDS AND SNOW ON GROUND SHOULD LOWER VISIBILITIES TO LESS THAN A QUARTER MILE. THE ONLY NEGATIVE I SEE IS THE FACT THAT COLD DENSE AIR IS IN PLACE..AND THIS COULD LIMIT THE TRANSFER OF MOMENTUM. OTHERWISE...MOST INGREDIENTS ARE IN PLACE FOR A 3 TO 5 HOUR PERIOD OF BLIZZARD CONDITIONS ACROSS THE WEST CENTRAL AND SOUTHWEST BEGINNING AROUND 3 AND EXTENDING INTO THE MID EVENING. BLIZZARD CONDITIONS MAY TAKE A FEW MORE HOURS...AROUND 5 PM OR SO TO REACH SIOUX COUNTY. UPDATE ISSUED AT 638 AM CST MON DEC 9 2013 NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME. ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20 BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18 UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CST MON DEC 9 2013 THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING. THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS AFTERNOON. OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE EXPECTED TO BE THE STRONGEST. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 332 AM CST MON DEC 9 2013 THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC ZONE OVER THE NORTHERN PLAINS. CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME. COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS THE FORECAST AREA. THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE. SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 121 PM CST MON DEC 9 2013 MAIN HAZARD TO AVIATION WILL BE STRONG WINDS...AND BLIZZARD CONDITIONS ACROSS THE SOUTHWEST AND WEST CENTRAL...IMPACTING PRIMARILY KDIK...BUT KISN-KBIS WILL BE IN THE PERIPHERY. MAIN TIMING WILL BE BETWEEN 3 PM AND MIDNIGHT. OUTSIDE OF THIS AREA...MVFR TO OCNLY IFR CONDITIONS AFTER 21Z WILL BE FOUND IN AREAS OF SNOW AND BLOWING SNOW. && .BIS WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ001>004-009>012-019>022-034-035-046. BLIZZARD WARNING UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NDZ017-018-031>033-040>045. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...TWH AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1102 AM CST MON DEC 9 2013 .UPDATE... ISSUED AT 1047 AM CST MON DEC 9 2013 WILL UPGRADE THE ADVISORY TO A BLIZZARD WARNING FOR THE WEST CENTRAL...SOUTHWEST AND FAR SOUTH CENTRAL. ALSO ADDING ANOTHER TIER OF COUNTIES INTO THE WINTER WEATHER ADVISORY...INCLUDING EMMONS BURLEIGH AND SHERIDAN. EXAMINED MODEL SOUNDINGS AND SEE STRONG POTENTIAL FOR 45 MPH WIND GUSTS WITH THE ALBERTA CLIPPER ACROSS THE SOUTHWEST. ALSO...SUPERSATURATED WITH RESPECT TO ICE IN THE DENDRITIC GROWTH ZONE FROM THE BOUNDARY LAYER TO 700 MB. WITH THAT IN MINE SEE POTENTIAL TO GENERATE A BURST OF SNOWFALL WITH THE SYSTEM. NOT MUCH MORE THAN 1 TO 2 INCHES BUT ADDING THE SNOW TO THE WINDS AND SNOW ON GROUND SHOULD LOWER VISIBILITIES TO LESS THAN A QUARTER MILE. THE ONLY NEGATIVE I SEE IS THE FACT THAT COLD DENSE AIR IS IN PLACE..AND THIS COULD LIMIT THE TRANSFER OF MOMENTUM. OTHERWISE...MOST INGREDIENTS ARE IN PLACE FOR A 3 TO 5 HOUR PERIOD OF BLIZZARD CONDITIONS ACROSS THE WEST CENTRAL AND SOUTHWEST BEGINNING AROUND 3 AND EXTENDING INTO THE MID EVENING. BLIZZARD CONDITIONS MAY TAKE A FEW MORE HOURS...AROUND 5 PM OR SO TO REACH SIOUX COUNTY. UPDATE ISSUED AT 638 AM CST MON DEC 9 2013 NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME. ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20 BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18 UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CST MON DEC 9 2013 THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING. THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS AFTERNOON. OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE EXPECTED TO BE THE STRONGEST. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 332 AM CST MON DEC 9 2013 THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC ZONE OVER THE NORTHERN PLAINS. CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME. COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS THE FORECAST AREA. THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE. SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1047 AM CST MON DEC 9 2013 MAIN HAZARD TO AVIATION WILL BE STRONG WINDS...AND BLIZZARD CONDITIONS ACROSS THE SOUTHWEST AND WEST CENTRAL...IMPACTING PRIMARILY KDIK...BUT KISN-KBIS WILL BE ION THE PERIPHERY. MAIN TIMING WILL BE BETWEEN 3 PM AND MIDNIGHT. OUTSIDE OF THIS AREA...MVFR TO OCNLY IFR CONDITIONS AFTER 21Z WILL BE FOUND IN AREAS OF SNOW AND BLOWING SNOW. && .BIS WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR NDZ001>004-009>012-019>022-034-035-046. BLIZZARD WARNING FROM 3 PM CST /2 PM MST/ THIS AFTERNOON TO MIDNIGHT CST /11 PM MST/ TONIGHT FOR NDZ017-018-031>033-040>045. WIND CHILL ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NDZ003>005- 011>013-022-023-025-036-037-047-048-050-051. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...TWH AVIATION...WAA
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
415 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/... 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 /21Z MONDAY THROUGH SATURDAY/... PRIMARILY MVFR STRATUS INTO TONIGHT WITH SOME IFR CIGS/VSBY IN THE MOUNTAINS AMID PATCHY DZ. SOME BREAKS POSSIBLE ACROSS SE OH AND NE KY TONIGHT. AN UPPER LEVEL TROF WILL APPROACH LATE TONIGHT AND COMBINED WITH A SURFACE WAVE TO THE SE WILL ALLOW SN OVERSPREAD MUCH OF THE AREA...HEAVIEST ACROSS THE LOWLANDS AND MOUNTAINS. CIGS WILL LOWER INTO IFR/LIFR ALONG WITH VSBY AS THE SN MOVES IN 09 TO 15Z. SOME IMPROVEMENT AFTER 15Z AS CIGS/VSBY RISE INTO MVFR AND TRYING TO SCT OU ACROSS SE OH/NE KY/W WV IN AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... 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. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H M M M M M H BKW CONSISTENCY H H H H L L L L L M H H EKN CONSISTENCY H H H H H L L L L L L L PKB CONSISTENCY H H H H H H H H H M M H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z TUESDAY... IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY. && .EQUIPMENT... ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE BY TUE MORNING. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE UNTIL AT LEAST TUE. && .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...30 SHORT TERM...TRM LONG TERM...RPY AVIATION...30 EQUIPMENT...TRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
305 PM EST MON DEC 9 2013 .SYNOPSIS... A WEAK SYSTEM CROSSES LATE TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY. ANOTHER SYSTEM THIS WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... 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/... ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING. EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW. THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY 0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION. CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2 INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE FREEZING MARK. HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER 20S FOR THE COALFIELDS. && .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 /20Z MONDAY THROUGH SATURDAY/... PRIMARILY MVFR STRATUS INTO TONIGHT WITH SOME IFR CIGS/VSBY IN THE MOUNTAINS AMID PATCHY DZ. SOME BREAKS POSSIBLE ACROSS SE OH AND NE KY TONIGHT. AN UPPER LEVEL TROF WILL APPROACH LATE TONIGHT AND COMBINED WITH A SURFACE WAVE TO THE SE WILL ALLOW SN OVERSPREAD MUCH OF THE AREA...HEAVIEST ACROSS THE LOWLANDS AND MOUNTAINS. CIGS WILL LOWER INTO IFR/LIFR ALONG WITH VSBY AS THE SN MOVES IN 09 TO 15Z. SOME IMPROVEMENT AFTER 15Z AS CIGS/VSBY RISE INTO MVFR AND TRYING TO SCT OU ACROSS SE OH/NE KY/W WV IN AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... 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. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H M M M M M H BKW CONSISTENCY H H H H L L L L L M H H EKN CONSISTENCY H H H H H L L L L L L L PKB CONSISTENCY H H H H H H H H H M M H CKB CONSISTENCY H H H H H H H H H H H H AFTER 18Z TUESDAY... IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY. && .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...30 SHORT TERM...50 LONG TERM...RPY AVIATION...30
AREA FORECAST DISCUSSION
NWS PORTLAND OR
1005 AM PST MON DEC 9 2013 .SYNOPSIS...LOWER PRESSURE OFFSHORE CONTINUES TO DRIVE WEAK EASTERLY FLOW THROUGH THE COLUMBIA GORGE AND INTO THE PORTLAND AREA. A WEAK CLIPPER SYSTEM WILL PUSH DOWN FROM THE YUKON BRINGING A CHANCE OF SNOW AND OR FREEZING DRIZZLE MAINLY FOR OUR NORTHERN ZONES INTO TUESDAY. WEDNESDAY SHOULD REMAIN CHILLY AND DRY...THOUGH A LITTLE WARMER THAN THE PAST COUPLE DAYS AS OUR AIR MASS SLOWLY MODERATES. THE NEXT SYSTEM LOOKS STRONGER...AND MAY ENCOUNTER A STUBBORN LOW- LEVEL COLD AIR MASS AS PRECIPITATION SPREADS ONSHORE. THIS MAY RESULT IN MORE FROZEN OR FREEZING PRECIPITATION BEFORE A PACIFIC AIR MASS FINALLY TAKES OVER LATE IN THE WEEK. && .UPDATE...WEAK LOW JUST OFF THE COAST HAVE DEVELOP A BIT OF HYBRID FREEZING RAIN AND DRIZZLE. A QUICK ANALYSIS OF MODEL SOUNDINGS AND VERTICAL TEMPERATURE PROFILE ESTIMATED OBSERVATIONS SHOW THE UPPER LAYER OF THE PRECIP GENERATION REGION (AROUND 850MB) IS SOMEWHERE AROUND -5 TO -6 DEGREES C...NOT QUITE COLD ENOUGH TO PRODUCE ALL SNOW AND STILL CLEARLY CAPABLE OF CREATING THE SUPERCOOLED WATER DROPS. REPORT FROM LONG BEACH IS A LIGHT GLAZE BUT ENOUGH TO IMPACT TRAVEL. HAVE ADDED A FREEZING DRIZZLE MENTION TO THE ADVISORY PLUS ADDED THE NORTH OREGON COAST, THE WILLIPA HILLS, AND THE NORTH COAST RANGE. PRESSURE GRADIENTS ARE STILL INDICATING OFFSHORE FLOW WHICH WILL LIMIT TEMPERATURES RISES. HAVE DECIDED TO ALSO PULL ALL RAIN MIX FROM THE FORECAST AS WINDS DO NOT APPEAR TO FAVOR SIGNIFICANT WARMING. FAIRLY SOLID CLOUD COVER WILL ALSO INHIBIT WARMING. SEEMS LIKE THIS INITIAL BAND WILL STILL ENCOUNTER DRIER INLAND AIR AS IT CROSSES THE COAST RANGES LEAVING SOME LIGHT FLURRIES ACROSS THE METRO AREA. LEFT THE ADVISORY ALONE FOR NOW COVERING THE METRO BUT DO HAVE CONCERNS FOR A LIGHT FREEZING DRIZZLE TO OCCUR FOR THE EVENING COMMUTE. LEAVING EARLY FROM WORK WOULD PROBABLY BE A GOOD IDEA. DONT EXPECT A WIDESPREAD ICING EVENT THIS AFTERNOON/EVENING BUT WOULD NOT BE SURPRISED TO SEE POCKETS OF LIGHT ICING UNDER OCCASIONAL FREEZING DRIZZLE MIXED IN WITH THE SHOW SHOWERS. AM STILL CONSIDERING WHAT TO MAKE OF THE OVERNIGHT CONDITIONS TONIGHT. A QUICK ANALYSIS SHOWS ANY MIXED FREEZING DRIZZLE WILL CONVERT BACK TO ALL SNOW AS THE MIDLEVELS COOL OVERNIGHT...EXCEPT FOR POSSIBLY THE COAST. PRECIP TYPING COULD BECOME MORE COMPLICATED OVERNIGHT AND EARLY DAYLIGHT TUESDAY FOR THE INLAND AREAS. WILL NEED TO SPEND MORE TIME WITH ANALYSIS THOUGH. UPDATED ZONES AND GRIDS ARE ON THEIR WAY. /JBONK && .PREV DISC... /ISSUED 400 AM PST MON DEC 9 2013/ SHORT TERM...TONIGHT THROUGH WEDNESDAY... ONE LAST BITTERLY COLD NIGHT OUT THERE TONIGHT BEFORE THE SLOW PROGRESSION OUT OF THE COLD SNAP BEGINS. SEEING SOME OF THAT WITH THE COAST REMAINING GENERALLY IN THE 20S. IT IS A BALMY 3 DEGREES IN EUGENE AND PLENTY OF TEENS INLAND. TEMPS AND DEW POINTS ARE UP A LITTLE FROM LAST NIGHT WHICH SHOULD PREVENT WIDESPREAD SINGLE DIGITS. LOWER CLOUDS ARE ROLLING INTO THE COAST THIS MORNING...AND KLGX RADAR DEPICTS SOME SHOWER ACTIVITY OFFSHORE THAT IS SOMEWHAT DYING OUT ON THE LEADING EDGE. LATEST HI-RES GUIDANCE SUGGESTS THAT NOT A WHOLE LOT OF INLAND PROGRESS THIS MORNING AS THE FLOW IS STILL MORE NORTHERLY ALOFT...BUT LIKELY SOME LIGHT SNOW OR FLURRIES FOR THE S WA/N OR COAST AND COAST RANGE. A SOMEWHAT CHALLENGING FORECAST COMING UP THE NEXT FEW DAYS AFTER THE NEAR TERM AS SEVERAL WEAK WAVES MOVE THROUGH BUT MIXED SIGNALS WITH REGARDS TO PRECIPITATION. COULD SEE SOME VERY LIGHT SNOW/FLURRIES OR SOME FREEZING DRIZZLE.AFTER THIS MORNING SEVERAL MODELS BRING LIGHT PRECIPITATION (0.02" QPF OR LESS) INTO THE INTERIOR THIS AFTERNOON. CURRENT KLGX DATA WOULD SUGGEST THAT PRECIPITATION WILL CONTINUE WORKING INLAND...BUT MAY HAVE PROBLEMS WITH THE DRY AIR MASS. MEANWHILE THE HRRR AND NAM KEEP PRECIPITATION CONFINED TO COAST AND COAST RANGE WHERE TEMPERATURE PROFILES BEGIN TO WARM GIVEN THE WEAK ONSHORE FLOW TO THE POINT WHERE PRECIP TYPE WOULD CHANGE TO RAIN OR MAYBE RAIN-SNOW MIX. MEANWHILE INLAND THE PROFILE WILL REMAIN ALL BELOW FREEZING. AFTER THAT THERE IS A MORE DISTINCT WAVE OFF THE COAST OF NORTHERN B.C. THAT WILL DROP S.E. AND PROVIDE A BIT MORE ORGANIZED LIFT TONIGHT INTO EARLY TUESDAY. THE MOISTURE LAYER LOOKS TO BE RATHER SHALLOW. THESE SITUATIONS TEND TO FAVOR FREEZING DRIZZLE...BUT ONLY IF YOU TAKE THEM FOR FACE VALUE AND DO NOT CONSIDER THE INITIAL AIR MASS THAT THE CLOUD FORMED IN OR THE ARMS THE SATURATED CLOUD IS MOVING INTO. SOUNDINGS SUGGEST THE TOP OF THE MOIST LAYER AROUND -5 TO -7C. IT IS INCORRECT TO SUGGEST THAT THERE WILL BE NO ICE CRYSTALS PRESENT IN THE CLOUD EVEN AT THESE TEMPERATURES...JUST A QUESTION OF IF THERE ARE ENOUGH. CANNOT IGNORE THE FACT THERE MAY ALSO BE SOME FREEZING DRIZZLE WHICH IF HITTING THE COLD ROADS WOULD FREEZE LIKE THE SNOW DID THE OTHER DAY. THAT SAID...AN INVESTIGATION OF DUAL-POLARIZATION DATA FROM KLGX AND SIMPLY DUE TO THE FACT THAT REFLECTIVITY RETURNS ARE AS HIGH AS 30-40 DBZ SUGGEST THAT P-TYPE...AT LEAST CURRENTLY AND WITH THE FIRST BATCH COMING IN IS SNOW AND NOT FREEZING DRIZZLE. THE 0Z QUILLAYUTE SOUNDING DOES SUGGEST A WARM LAYER ABOVE THE MOIST LAYER.. BUT THE POTENTIAL OF FREEZING DRIZZLE CANNOT BE IGNORED AS THE LOWER LEVEL PROFILE WARMS AND REDUCES ICE CRYSTAL AVAILABILITY ESPECIALLY TOWARDS TUESDAY. AND ANY ACCUMULATING FREEZING DRIZZLE WOULD WARRANT AN ADVISORY...ALSO DUE TO THE FACT DEW POINTS WILL BE MUCH HIGHER MONDAY NIGHT INTO TUESDAY MORNING...ROADS HAVE THE POTENTIAL TO BE QUITE HAZARDOUS...REGARDLESS OF THE PRECIP TYPE OR HOW MUCH/HOW LITTLE SNOW ACTUALLY FALLS. SREF PLUMES KEEP ANYWHERE FROM LIGHT SNOW ACCUMS TO UP TO AN INCH IN THE METRO. MODELS CONTINUE TO FAVOR THE KELSO/CASTLE ROCK AREA AND THE I-5 CORRIDOR IN WASHINGTON FOR THE MOST QPF. THEREFORE SEE NO REASON AT LEAST AT THIS TIME TO CHANGE THE HEADLINE...BUT WILL FOCUS ON FREEZING DRIZZLE/SNOW POTENTIAL AND ROAD IMPACTS. SINCE THE CENTRAL VALLEY DOES NOT LOOK TO SEE MUCH SNOW...I CAN FORESEE A SITUATION WHERE IF FREEZING DRIZZLE DOMINATES AND THE PRECIP GETS A BIT FARTHER SOUTH...THAT AN ADVISORY WOULD BE WARRANTED...BUT CONFIDENCE IS LOW. DO STILL THINK THAT 1-2" ARE POSSIBLE IF THE P-TYPE REMAINS SNOW MAINLY NORTH OF THE COLUMBIA RIVER AND ALSO TOWARDS ST HELENS/SCAPPOOSE. I HOPE THIS DOES NOT COME BACK TO HAUNT ME...BUT AM CONTEMPLATING TO REMOVING THE CENTRAL WILLAMETTE VALLEY FROM THE WINTER WX ADVISORY...AS QPF IN THESE AREAS DOES NOT SUPPORT AT THAT MUCH IN THE WAY OF SNOW. IF FREEZING DRIZZLE IS THE MORE DOMINANT P-TYPE...THAN AN ADVISORY WOULD THEN BE WARRANTED. WILL WORK UP THE WSW HERE WITH REFINED TIMING AND FINAL DECISIONS SHORTLY AND SEND AN AMENDED AFD WITH THE HEADLINES. THE MAIN JET ENERGY COMING OUT OF WESTERN CANADA SHOULD SHIFT FARTHER EAST BY WEDNESDAY...ALLOWING SOME CLEARING AND POSSIBLY ANOTHER CLEAR CALM AND CHILLY MORNING FOR SOME AREAS WED MORNING. EXPECT THERE TO THEN BE FOG/FREEZING FOG. AFTER BURN OFF AND WITH SOME SUNSHINE AND A SOMEWHAT MODERATED AIR MASS...MOST AREAS SHOULD BE ABLE TO GET ABOVE FREEZING WEDNESDAY. HAVE DRIED OUT THE FORECAST FOR WEDS AND WEDNESDAY NIGHT WITH THE EXPECTED TREND OF BACKING OFF THE ARRIVAL OF THE PACIFIC SYSTEM WITH A COLD AND STRONG UPPER RIDGE IN PLACE. /KMD LEFT PREVIOUS DISCUSSION IN PLACE FOR THE LATTER PART OF THE SHORT TERM FROM THE EVENING SHIFT AS MUCH OF THIS SHIFT WAS SPENT FINE TUNING THE DETAILS THROUGH WEDNESDAY NIGHT.... NO DOUBT THIS IS AN HISTORIC COLD AIR MASS. WHICH BRINGS US TO OUR NEXT FORECAST CHALLENGE...THE PRECIPITATION TYPE EXPECTED FROM OUR NEXT EVENT. CONSIDERING THE MAGNITUDE OF COLD ASSOCIATED WITH THIS AIR MASS...IT IS VERY HARD TO BELIEVE WEAK CLIPPER SYSTEMS WILL BE SUFFICIENT TO ERODE THE COLD AIR ENTRENCHED OVER THE PACIFIC NORTHWEST. WE CONTINUE TO DISAGREE WITH MODEL GUIDANCE THAT SUGGESTS THE COLD AIR WILL SCOUR OUT QUICKLY...AND OUR TEMPERATURE AND PRECIPITATION TYPE FORECAST REFLECTS THAT ALL THE WAY INTO THURSDAY. WEAGLE LONG TERM...NO CHANGES TO THE GRIDS OTHER THAN TO BACK OFF ON POPS A BIT TO START THURSDAY SO REST OF THE DISCUSSION REMAINS UNCHANGED...WILL LET THE DAY SHIFT REVISIT THE CHANGE IN TIMING AND IMPACTS ON THERMAL PROFILES...WEDNESDAY NIGHT THROUGH SUNDAY...OVERALL NO CHANGES TO THE THINKING BEHIND THE EXTENDED FORECAST. DID SOME MANIPULATION OF THE GRIDS TO ATTEMPT TO BETTER EXPRESS THE MIXED PRECIPITATION POTENTIAL WITH THE LATE WEEK SYSTEM. WEAGLE PREVIOUS DISCUSSION FOLLOWS...THE WELL ESTABLISHED COLD ARCTIC AIR MASS WILL BEGIN TO MODERATE AS FLOW ALOFT BECOMES MORE WESTERLY. TEMPERATURES LOOK TO TREND BACK TO SEASONAL NORMALS THROUGH THE SECOND HALF OF NEXT WEEK. THE 12Z GFS AND ECMWF ARE A BIT SLOWER TO BRING A SYSTEM ONSHORE EARLY THURSDAY SO HAVE ADJUSTED POP GRIDS TO REFLECT THIS. FORECAST MODELS BRING THE HEAVIEST PRECIP ONSHORE MIDDAY THURSDAY...WITH THE GFS SOLUTION ABOUT 6 HOURS FASTER. THERE REMAINS SOME CONCERN THAT THE MODELS ARE TOO QUICK TO WARM THE AIR MASS AFTER THIS PERIOD OF RECORD-SETTING COLD...SO IT IS POSSIBLE THAT THIS PRECIPITATION MAY BEGIN IN THE FORM OF SNOW OR FREEZING RAIN. THIS IS PARTICULARLY THE CASE FOR UPPER HOOD RIVER...THE COLUMBIA RIVER GORGE..AND THE NORTHERN WILLAMETTE VALLEY. OTHERWISE RAIN AND CASCADE SNOW IS EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT. THERE MAY BE A BRIEF DRY PERIOD AT LEAST PART OF THE DAY SATURDAY AS LOW LEVEL FLOW WILL TURN SOUTHERLY BEFORE THE THE NEXT SYSTEM ARRIVES SATURDAY AFTERNOON OR EVENING BRINGING RAIN ACROSS THE FORECAST AREA.CULLEN && .AVIATION...MAINLY VFR THROUGH 18Z...WITH POCKETS OF IFR IN FOG IN S WILLAMETTE VALLEY. COAST WILL BE PREDOMINANTLY MVFR IN LIGHT SNOW...WITH OCCASIONAL IFR IN SNOW POSSIBLE THROUGH EARLY TUESDAY. FREEZING DRIZZLE IS ALSO POSSIBLE NEAR THE COAST. INLAND FROM KSLE NORTH EXPECT MVFR IN OCCASIONAL LIGHT SNOW...PRIMARILY AFTER 18Z...WITH IFR IN SNOW POSSIBLE AFTER 03Z. SOUTH OF KSLE WILL BE VFR THROUGH 00Z. KPDX AND APPROACHES...VFR WITH LIGHT EAST WINDS. OCCASIONAL MVFR IN FLURRIES OR LIGHT SNOW TODAY...ESPECIALLY AFTER 18Z. IFR IN SNOW POSSIBLE LATE TONIGHT AFTER 03Z. && .MARINE...NO UPDATES. PREVIOUS DISCUSSION FOLLOWS. BENIGN WEATHER THROUGH WED. HIGH PRES OVER PAC NW MAINTAINS LIGHT OFFSHORE FLOW THROUGH WED. WILL WILL TURN MORE W TO SW TUE AND WED AS HIGH WEAKENS AND LOWER PRES APPROACHES FROM THE W. SEAS HOLDING AT 2 TO 4 FT TODAY AND TUE...THEN BUILD SLIGHTLY LATER TUE AND WED. STRONG COLD FRONT WILL ARRIVE ON THU...WITH S GALES EXPECTED. SEAS WILL BUILD BACK CLOSER TO 10 FT. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM PST TUESDAY FOR LOWER COLUMBIA. WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR COAST RANGE OF NORTHWEST OREGON-NORTH OREGON COAST. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM PST TUESDAY FOR GREATER PORTLAND METRO AREA. WA...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM PST TUESDAY FOR I-5 CORRIDOR IN COWLITZ COUNTY. WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR SOUTH WASHINGTON COAST-WILLAPA HILLS. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM PST TUESDAY FOR GREATER VANCOUVER AREA. PZ...NONE. && $$ MORE WEATHER INFORMATION ONLINE AT.. HTTP://WEATHER.GOV/PORTLAND INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1124 AM CST MON DEC 9 2013 .UPDATE... UPDATED FOR 18Z AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 1027 AM CST MON DEC 9 2013/ DISCUSSION... ANOTHER COLD DAY ON TAP ACROSS THE MIDSOUTH. CLOUDS ARE HANGING TOUGH AND LATEST RAP SOUNDINGS INDICATE THAT THEY WILL REMAIN FOR THE REST OF THE DAY. THE LACK OF SUN WILL MAKE IT TOUGH FOR TEMPS TO CLIMB MUCH SO KNOCKED A COUPLE OF DEGREES OFF SOUTH OF I-40. UPDATE OUT. SJM && .PREV DISCUSSION... /ISSUED 442 AM CST MON DEC 9 2013/ WEATHER CONDITIONS WERE CLOUDY AND COLD ACROSS THE MIDSOUTH EARLY THIS MORNING. PRECIPITATION HAD MOVED OUT OF THE AREA AND ONLY LIGHT FOG WAS BEING REPORTED IN A FEW SPOTS. THUS A MUCH QUIETER NIGHT WEATHERWISE THAN LAST NIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE UPCOMING WEEK. THE BIGGEST DISAGREEMENT IS THAT THE NAM SHOWS A LITTLE MORE PRECIPITATION AND IS FURTHER NORTH WITH THE PRECIPITATION TONIGHT THAN THE GFS AND ECMWF. VERY COLD WEATHER WILL CONTINUE THROUGH MUCH OF THE WORK WEEK WITH ONE MORE THREAT OF FREEZING RAIN AND SLEET TONIGHT. FOR TODAY...CLOUDS ARE EXPECTED TO GRADUALLY BREAK UP THIS MORNING LEAVING PARTIAL SUNSHINE ACROSS THE AREA BY THIS AFTERNOON. ANOTHER PUSH OF MODIFIED POLAR AIR WILL MOVE INTO THE MIDSOUTH KEEPING IT VERY COLD ACROSS MOST OF THE REGION. LEFT IN A SLIGHT CHANCE OF RAIN IN ADVANCE OF THE NEXT SYSTEM ACROSS EXTREME SOUTHERN PORTIONS OF NORTH MS THIS AFTERNOON...OTHERWISE IT WILL BE A DRY DAY ACROSS THE MIDSOUTH. FOR TONIGHT...WEAK SURFACE LOW PRESSURE WILL TRACK TO THE SOUTHEAST OF THE MIDSOUTH. THIS PLACES THE MIDSOUTH ON THE NORTHWESTERN FRINGE OF MOST OF THE PRECIPITATION WITH THE HIGHEST POPS AND AMOUNTS FORECAST THROUGH NORTH MS. GENERALLY TOOK A COMPROMISE BETWEEN THE VARIOUS MODELS. COLDER AIR WILL CONTINUE TO ADVECT INTO THE AREA FROM THE NORTHWEST. AS A RESULT...PRECIPITATION WILL BE CHANGING TO FREEZING RAIN AND SLEET FROM THE NORTHWEST. THERE IS A SLIGHT CHANCE OF LIGHT SNOW NORTH OF INTERSTATE 40 MAINLY DUE TO AN UPPER LEVEL TROUGH APPROACHING FROM THE WEST...LITTLE IF ANY ACCUMULATION OF SNOW IS EXPECTED. ATTM...THINK THE BEST CHANCE FOR ANY ICE ACCUMULATION FROM FREEZING RAIN AND SLEET WILL BE ALONG AND SOUTH OF INTERSTATE 40 ACROSS PORTIONS OF WEST TENNESSEE...EAST CENTRAL ARKANSAS AND NORTH MISSISSIPPI. A WINTER WEATHER ADVISORY MAY NEED TO BE ISSUED FOR PORTIONS OF THIS AREA LATER TODAY...CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE AT THIS TIME. ANY ICE ACCUMULATIONS ARE FORECAST TO BE LIGHT AND LESS THAN 1/10 OF AN INCH. PRECIPITATION ACROSS MUCH OF NORTH MISSISSIPPI WILL BEGIN AS RAIN MIXED WITH FREEZING RAIN IN SOME LOCATIONS...GRADUALLY BECOMING FREEZING RAIN AND SLEET AS COLDER AIR PUSHES IN FROM THE NORTHWEST. ONLY MINOR IF ANY ACCUMULATIONS OF SLEET ARE EXPECTED. THE PRECIPITATION WILL MOVE EAST OF THE MIDSOUTH EARLY TUESDAY WITH STRONG COLD HIGH PRESSURE SETTLING OVER THE MIDSOUTH. THE GOOD NEWS IS THAT NO MORE PRECIPITATION IS FORECAST UNTIL FRIDAY. QUITE COLD CONDITIONS ARE FORECAST WEDNESDAY MORNING UNDER MOSTLY CLEAR SKIES WITH LOWS IN THE TEENS ACROSS A LARGE SECTION OF THE AREA. THE HIGH PRESSURE SYSTEM WILL MOVE TO THE EAST DURING THE DAY WEDNESDAY WITH SLIGHTLY LESS COLD TEMPERATURES...BUT DID NOT GO AS WARM AS THE MEX GUIDANCE INDICATES. ANOTHER SURGE OF MODIFIED ARCTIC AIR WILL PUSH INTO THE REGION WEDNESDAY NIGHT WITH THURSDAY MORNING FORECAST TO BE THE COLDEST OF THE WEEK. LOW TEMPERATURES WILL DROP INTO THE TEENS ACROSS MUCH OF THE AREA WITH LOWER TEENS FOR SOME AREAS. WILL NEED TO MONITOR WIND CHILL READINGS AS THEY MAY DROP TO NEAR ZERO ACROSS PORTIONS OF NORTHWEST TN. A LARGE SCALE UPPER LEVEL TROUGH WILL APPROACH THE MIDSOUTH FROM THE WEST FRIDAY BRINGING OUR NEXT CHANCE OF PRECIPITATION. AT THIS TIME...INDICATIONS ARE THAT MOST IF NOT ALL OF THE PRECIPITATION WILL BE RAIN BUT WILL NEED TO KEEP AN EYE ON THIS IN CASE IT DOES NOT WARM UP AS QUICKLY AS EXPECTED...ESPECIALLY ACROSS NORTHERN AREAS. THE UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION FRIDAY NIGHT AND EARLY SATURDAY WITH WIDESPREAD RAIN. POPS WILL NEED TO BE INCREASED IN LATER FORECASTS IF THESE MODEL TRENDS PERSIST. DRY AND COOLER WEATHER IS FORECAST SUNDAY NIGHT AND MONDAY AS THE TROUGH MOVES OFF TO THE EAST. JCL && .AVIATION... 18Z TAF CYCLE CONFIDENCE INCREASING IN RESPECT TO A BRIEF WINTER WEATHER EVENT MOVING UP FROM THE SOUTHWEST TONIGHT...AFFECTING MEM...TUP...AND MKL. A LIGHT SNOW AND SLEET MIX WILL OCCASIONALLY FALL AT MEM AND MKL STARTING THIS EVENING...AND AT THE SAME TIME PRECIPITATION WILL START OUT AS A COLD RAIN AT TUP. THEN SOMETIME AFTER MIDNIGHT FEEL PRECIPITATION WILL START TAPERING OFF WITH THE POSSIBILITY OF PATCHY FREEZING DRIZZLE FORMING. CIGS WILL BE MAINLY MVFR...WITH OCCASIONAL IFR CONDITIONS AT TUP. JBR MAY SEE OCCASIONAL VFR CONDITIONS NEAR SUNSET. WINDS WILL BE NORTHERLY AT 8-12 KTS BACKING NORTHWESTERLY LATE. JAB && .PRELIMINARY POINT TEMPS/POPS... MEM 36 24 36 23 / 10 40 10 10 MKL 36 22 35 18 / 10 40 10 10 JBR 32 20 31 19 / 10 20 10 10 TUP 40 29 40 23 / 10 80 10 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1027 AM CST MON DEC 9 2013 .DISCUSSION... ANOTHER COLD DAY ON TAP ACROSS THE MIDSOUTH. CLOUDS ARE HANGING TOUGH AND LATEST RAP SOUNDINGS INDICATE THAT THEY WILL REMAIN FOR THE REST OF THE DAY. THE LACK OF SUN WILL MAKE IT TOUGH FOR TEMPS TO CLIMB MUCH SO KNOCKED A COUPLE OF DEGREES OFF SOUTH OF I-40. UPDATE OUT. SJM && PREV DISCUSSION... /ISSUED 442 AM CST MON DEC 9 2013/ WEATHER CONDITIONS WERE CLOUDY AND COLD ACROSS THE MIDSOUTH EARLY THIS MORNING. PRECIPITATION HAD MOVED OUT OF THE AREA AND ONLY LIGHT FOG WAS BEING REPORTED IN A FEW SPOTS. THUS A MUCH QUIETER NIGHT WEATHERWISE THAN LAST NIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE UPCOMING WEEK. THE BIGGEST DISAGREEMENT IS THAT THE NAM SHOWS A LITTLE MORE PRECIPITATION AND IS FURTHER NORTH WITH THE PRECIPITATION TONIGHT THAN THE GFS AND ECMWF. VERY COLD WEATHER WILL CONTINUE THROUGH MUCH OF THE WORK WEEK WITH ONE MORE THREAT OF FREEZING RAIN AND SLEET TONIGHT. FOR TODAY...CLOUDS ARE EXPECTED TO GRADUALLY BREAK UP THIS MORNING LEAVING PARTIAL SUNSHINE ACROSS THE AREA BY THIS AFTERNOON. ANOTHER PUSH OF MODIFIED POLAR AIR WILL MOVE INTO THE MIDSOUTH KEEPING IT VERY COLD ACROSS MOST OF THE REGION. LEFT IN A SLIGHT CHANCE OF RAIN IN ADVANCE OF THE NEXT SYSTEM ACROSS EXTREME SOUTHERN PORTIONS OF NORTH MS THIS AFTERNOON...OTHERWISE IT WILL BE A DRY DAY ACROSS THE MIDSOUTH. FOR TONIGHT...WEAK SURFACE LOW PRESSURE WILL TRACK TO THE SOUTHEAST OF THE MIDSOUTH. THIS PLACES THE MIDSOUTH ON THE NORTHWESTERN FRINGE OF MOST OF THE PRECIPITATION WITH THE HIGHEST POPS AND AMOUNTS FORECAST THROUGH NORTH MS. GENERALLY TOOK A COMPROMISE BETWEEN THE VARIOUS MODELS. COLDER AIR WILL CONTINUE TO ADVECT INTO THE AREA FROM THE NORTHWEST. AS A RESULT...PRECIPITATION WILL BE CHANGING TO FREEZING RAIN AND SLEET FROM THE NORTHWEST. THERE IS A SLIGHT CHANCE OF LIGHT SNOW NORTH OF INTERSTATE 40 MAINLY DUE TO AN UPPER LEVEL TROUGH APPROACHING FROM THE WEST...LITTLE IF ANY ACCUMULATION OF SNOW IS EXPECTED. ATTM...THINK THE BEST CHANCE FOR ANY ICE ACCUMULATION FROM FREEZING RAIN AND SLEET WILL BE ALONG AND SOUTH OF INTERSTATE 40 ACROSS PORTIONS OF WEST TENNESSEE...EAST CENTRAL ARKANSAS AND NORTH MISSISSIPPI. A WINTER WEATHER ADVISORY MAY NEED TO BE ISSUED FOR PORTIONS OF THIS AREA LATER TODAY...CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE AT THIS TIME. ANY ICE ACCUMULATIONS ARE FORECAST TO BE LIGHT AND LESS THAN 1/10 OF AN INCH. PRECIPITATION ACROSS MUCH OF NORTH MISSISSIPPI WILL BEGIN AS RAIN MIXED WITH FREEZING RAIN IN SOME LOCATIONS...GRADUALLY BECOMING FREEZING RAIN AND SLEET AS COLDER AIR PUSHES IN FROM THE NORTHWEST. ONLY MINOR IF ANY ACCUMULATIONS OF SLEET ARE EXPECTED. THE PRECIPITATION WILL MOVE EAST OF THE MIDSOUTH EARLY TUESDAY WITH STRONG COLD HIGH PRESSURE SETTLING OVER THE MIDSOUTH. THE GOOD NEWS IS THAT NO MORE PRECIPITATION IS FORECAST UNTIL FRIDAY. QUITE COLD CONDITIONS ARE FORECAST WEDNESDAY MORNING UNDER MOSTLY CLEAR SKIES WITH LOWS IN THE TEENS ACROSS A LARGE SECTION OF THE AREA. THE HIGH PRESSURE SYSTEM WILL MOVE TO THE EAST DURING THE DAY WEDNESDAY WITH SLIGHTLY LESS COLD TEMPERATURES...BUT DID NOT GO AS WARM AS THE MEX GUIDANCE INDICATES. ANOTHER SURGE OF MODIFIED ARCTIC AIR WILL PUSH INTO THE REGION WEDNESDAY NIGHT WITH THURSDAY MORNING FORECAST TO BE THE COLDEST OF THE WEEK. LOW TEMPERATURES WILL DROP INTO THE TEENS ACROSS MUCH OF THE AREA WITH LOWER TEENS FOR SOME AREAS. WILL NEED TO MONITOR WIND CHILL READINGS AS THEY MAY DROP TO NEAR ZERO ACROSS PORTIONS OF NORTHWEST TN. A LARGE SCALE UPPER LEVEL TROUGH WILL APPROACH THE MIDSOUTH FROM THE WEST FRIDAY BRINGING OUR NEXT CHANCE OF PRECIPITATION. AT THIS TIME...INDICATIONS ARE THAT MOST IF NOT ALL OF THE PRECIPITATION WILL BE RAIN BUT WILL NEED TO KEEP AN EYE ON THIS IN CASE IT DOES NOT WARM UP AS QUICKLY AS EXPECTED...ESPECIALLY ACROSS NORTHERN AREAS. THE UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION FRIDAY NIGHT AND EARLY SATURDAY WITH WIDESPREAD RAIN. POPS WILL NEED TO BE INCREASED IN LATER FORECASTS IF THESE MODEL TRENDS PERSIST. DRY AND COOLER WEATHER IS FORECAST SUNDAY NIGHT AND MONDAY AS THE TROUGH MOVES OFF TO THE EAST. JCL && .AVIATION... 12Z TAF CYCLE LOW CONFIDENCE TAF FORECAST OVER THE NEXT 24 HOURS. MVFR CEILINGS SHOULD GRADUALLY LIFT TO VFR CONDS THIS AFTERNOON...EXCEPT FOR TUP WHERE MVFR CIGS WILL PREVAIL FOR MOST OF THE DAY. LOW AND MID LEVEL MOISTURE WILL ADVANCE AHEAD OF A SURFACE LOW PRESSURE SYSTEM THROUGHOUT THE DAY. EVENTUALLY RAIN WILL GRADUALLY SPREAD NORTHWARD AND OVERRIDE COLD DRY AIR THAT IS MOVING SOUTHEASTWARD. THIS WILL LEAD TO A CHANCE OF RA CHANGING OVER TO FZRA AND PL AT MKL...MEM...AND TUP SOMETIME AFTER 03Z. WINDS WILL REMAIN FROM THE NORTH 8-10 KTS THROUGH THE END OF THE TAF PERIOD. ALL TYPES OF PRECIPITATION WILL COME TO AN END FOLLOWING THE END OF THIS CYCLE. AC3 && .AVIATION... && .PRELIMINARY POINT TEMPS/POPS... MEM 36 24 36 23 / 10 40 10 10 MKL 36 22 35 18 / 10 40 10 10 JBR 32 20 31 19 / 10 20 10 10 TUP 40 29 40 23 / 10 80 10 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
137 PM CST Mon Dec 9 2013 .UPDATE... Quick update to continue patchy freezing fog for portions of the Big Country this afternoon. Visibilities for the most part have been improving but Abilene continues to see visibilities between 1/4 and 1/2 miles. Should see visibilities across this area improve to around 2 miles within the next couple of hours. Temperatures currently range from the upper 20s and and lower 30s north of a San Angelo to San Saba line, with upper 30s generally south of this line. Temperatures should remain nearly steady through the rest of this afternoon and made adjustments to hourly temperatures to account for this. No other changes needed at this time. && .PREV DISCUSSION... /ISSUED 1157 AM CST MON DEC 9 2013/ AVIATION... /18Z TAFS/ Widespread stratus and FG/FZFG will persist across the terminals this afternoon. Visibilities are beginning to improve late this morning but latest guidance indicates IFR/LIFR CIGS persisting for the remainder of the afternoon hours. The exception will be KSOA where CIGS should remain mainly MVFR. Not much improvement expected across the remaining terminals this evening with IFR CIGS continuing through late evening. KABI will likely hold onto some MVFR visibilities as well through the evening hours. Drier air filters into the region overnight with skies clearing across the terminals after 09Z. PREV DISCUSSION... /ISSUED 753 AM CST MON DEC 9 2013/ UPDATE... Expanded the Freezing Fog Advisory another row of counties. DISCUSSION... The fog continues to expand into the Concho Valley, so I have expanded the Freezing Fog Advisory to include Irion, Tom Green, Concho, Menard, and Schleicher counties. We will continue to monitor to progress of the fog. PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 9 2013/ UPDATE... To expand the Freezing Fog Advisory... DISCUSSION... Areas of freezing fog across the Big Country, Heartland and Northwest Hill country continue to expand to the south and west. Temperatures are below freezing across the entire area and given the expansion of the fog, I went ahead and expanded the advisory to include all of the Big Country and the northern Concho Valley. The freezing fog could approach areas farther south in the next few hours, including San Angelo, so I will continue to monitor trends and these counties may need to eventually be added. Otherwise, the rest of the forecast looks on track. Please see the aviation discussion below... AVIATION... Stratus/fog continues to expand through much of West Central Texas this morning resulting in IFR to LIFR conditions. KSOA is a bit more tricky, as the stratus to the south is struggling to expand northward. For now, I have indicated MVFR ceilings by 14z, and will continue to monitor. Some improvement in ceilings is forecast by late morning or early afternoon, with MVFR ceilings returning to most sites. Winds today will be from the north at 5 to 10 knots PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/ SHORT TERM... Today and Tonight A cold front is currently moving through the Big Country and should be approaching the Interstate 10 corridor shortly after sunrise. Winds behind the front will become north and increase to about 8 to 12 mph, with colder air slowly filtering into West Central Texas. In addition, areas of freezing fog are evident just to the east of our area, which has slowly been creeping west. I expect this freezing fog to expand to a Throckmorton, to Coleman, to Mason line in the next few hours. A freezing fog advisory is in effect for parts of the Heartland through 9 AM, and I will continue to monitor trends for the possibility of expanding it north into parts of the Big Country and south toward Mason county. The HRRR is also indicating some post frontal fog across parts of the Big Country, which will need to be monitored. Stratus should fill in this morning behind the front, with much of the area becoming overcast by mid morning. Given the expected cloud cover and cold air advection, I lowered high temperatures slightly. Highs will range from the upper 20s north of Interstate 20, to the mid 40s across the Interstate 10 corridor. Cloudy skies through much of the overnight period will not support ideal radiational cooling conditions, but given the cold airmass that will be filtering into the region, I went ahead and lowered low temperatures slightly. Tuesday morning low temperatures will generally be in the teens to lower 20s across all of West Central Texas. Daniels LONG TERM... Tuesday through Sunday As a fast moving shortwave trough moves through the Great Lakes region Tuesday night into Wednesday, a cold front will move into Texas, causing another brief cooling for Wednesday into Thursday. However, no precipitation is expected with the front. Lee troughing on Thursday will allow winds to quickly turn back to the south in our area, allowing temperatures to warm back up across the area Thursday and especially Friday. An upper level low initially off the coast of California on Monday will move across the Desert Southwest and into the Texas panhandle by Friday. As this low approaches, weak shortwaves will move across the area out ahead of it, interacting with moisture return and low level warm air advection, resulting in at least a slight chance for showers mainly Thursday afternoon and Thursday night, with some lingering showers moving out of the area on Friday. The upper level low will then move east towards the Mississippi Valley by Saturday, sending a cold front into the area. And while the cold front will slow the warming trend, the air mass behind the front will not be of arctic origin, so while we have gone cooler than the MOS guidance for Saturday and Sunday, temperatures should continue to trend closer to normal values through the weekend. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 29 17 40 27 41 / 10 5 0 0 0 San Angelo 33 21 44 26 47 / 10 5 0 0 0 Junction 41 23 47 24 53 / 10 5 0 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 99/99
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1157 AM CST MON DEC 9 2013 .AVIATION... /18Z TAFS/ Widespread stratus and FG/FZFG will persist across the terminals this afternoon. Visibilities are beginning to improve late this morning but latest guidance indicates IFR/LIFR CIGS persisting for the remainder of the afternoon hours. The exception will be KSOA where CIGS should remain mainly MVFR. Not much improvement expected across the remaining terminals this evening with IFR CIGS continuing through late evening. KABI will likely hold onto some MVFR visibilities as well through the evening hours. Drier air filters into the region overnight with skies clearing across the terminals after 09Z. && .PREV DISCUSSION... /ISSUED 753 AM CST MON DEC 9 2013/ UPDATE... Expanded the Freezing Fog Advisory another row of counties. DISCUSSION... The fog continues to expand into the Concho Valley, so I have expanded the Freezing Fog Advisory to include Irion, Tom Green, Concho, Menard, and Schleicher counties. We will continue to monitor to progress of the fog. PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 9 2013/ UPDATE... To expand the Freezing Fog Advisory... DISCUSSION... Areas of freezing fog across the Big Country, Heartland and Northwest Hill country continue to expand to the south and west. Temperatures are below freezing across the entire area and given the expansion of the fog, I went ahead and expanded the advisory to include all of the Big Country and the northern Concho Valley. The freezing fog could approach areas farther south in the next few hours, including San Angelo, so I will continue to monitor trends and these counties may need to eventually be added. Otherwise, the rest of the forecast looks on track. Please see the aviation discussion below... AVIATION... Stratus/fog continues to expand through much of West Central Texas this morning resulting in IFR to LIFR conditions. KSOA is a bit more tricky, as the stratus to the south is struggling to expand northward. For now, I have indicated MVFR ceilings by 14z, and will continue to monitor. Some improvement in ceilings is forecast by late morning or early afternoon, with MVFR ceilings returning to most sites. Winds today will be from the north at 5 to 10 knots PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/ SHORT TERM... Today and Tonight A cold front is currently moving through the Big Country and should be approaching the Interstate 10 corridor shortly after sunrise. Winds behind the front will become north and increase to about 8 to 12 mph, with colder air slowly filtering into West Central Texas. In addition, areas of freezing fog are evident just to the east of our area, which has slowly been creeping west. I expect this freezing fog to expand to a Throckmorton, to Coleman, to Mason line in the next few hours. A freezing fog advisory is in effect for parts of the Heartland through 9 AM, and I will continue to monitor trends for the possibility of expanding it north into parts of the Big Country and south toward Mason county. The HRRR is also indicating some post frontal fog across parts of the Big Country, which will need to be monitored. Stratus should fill in this morning behind the front, with much of the area becoming overcast by mid morning. Given the expected cloud cover and cold air advection, I lowered high temperatures slightly. Highs will range from the upper 20s north of Interstate 20, to the mid 40s across the Interstate 10 corridor. Cloudy skies through much of the overnight period will not support ideal radiational cooling conditions, but given the cold airmass that will be filtering into the region, I went ahead and lowered low temperatures slightly. Tuesday morning low temperatures will generally be in the teens to lower 20s across all of West Central Texas. Daniels LONG TERM... Tuesday through Sunday As a fast moving shortwave trough moves through the Great Lakes region Tuesday night into Wednesday, a cold front will move into Texas, causing another brief cooling for Wednesday into Thursday. However, no precipitation is expected with the front. Lee troughing on Thursday will allow winds to quickly turn back to the south in our area, allowing temperatures to warm back up across the area Thursday and especially Friday. An upper level low initially off the coast of California on Monday will move across the Desert Southwest and into the Texas panhandle by Friday. As this low approaches, weak shortwaves will move across the area out ahead of it, interacting with moisture return and low level warm air advection, resulting in at least a slight chance for showers mainly Thursday afternoon and Thursday night, with some lingering showers moving out of the area on Friday. The upper level low will then move east towards the Mississippi Valley by Saturday, sending a cold front into the area. And while the cold front will slow the warming trend, the air mass behind the front will not be of arctic origin, so while we have gone cooler than the MOS guidance for Saturday and Sunday, temperatures should continue to trend closer to normal values through the weekend. 20 && .PRELIMINARY POINT TEMPS/POPS... Abilene 26 18 39 27 42 / 10 5 0 0 0 San Angelo 35 19 44 26 46 / 10 5 0 0 0 Junction 46 22 47 24 52 / 10 10 5 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... FREEZING FOG ADVISORY until Noon CST today FOR THE FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher... Haskell...Irion...Jones...Kimble...Mason...McCulloch...Menard... Nolan...Runnels...San Saba...Schleicher...Shackelford... Sterling...Taylor...Throckmorton...Tom Green. && $$ 24
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST 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 18Z TAF ISSUANCE ISSUED AT 1128 AM CST MON DEC 9 2013 LIGHT SNOW AND FLURRIES ARE STUBBORNLY STICKING AROUND CENTRAL AND NORTH-CENTRAL WISCONSIN AT MIDDAY...AND HAVE TO EXTEND LOWER VSBYS IN LIGHT SNOW INTO MID-AFTERNOON. WEST WINDS WILL ALSO REMAIN GUSTY THROUGH THE AFTERNOON BEFORE THE GUSTINESS SUBSIDES BY EARLY THIS EVENING. A PERIOD OF VFR CONDITIONS WILL THEN FOLLOW UNTIL LATE TONIGHT...AND THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL BRING A QUICK ROUND OF SNOW AND LOWERING CIGS LATE TONIGHT INTO TUESDAY MORNING. VSBYS IN THE SNOW TO AT LEAST FALL INTO THE IFR RANGE...AND POSSIBLY LOWER BASED ON OBSERVATIONS OVER MONTANA. && .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.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 AM CST MON DEC 9 2013 .UPDATE... ISSUED AT 1044 AM CST MON DEC 9 2013 TEMPERATURES HAVE NOT RISEN ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS MORNING WHILE WINDS HAVE CONTINUED TO INCREASE TO AROUND 20 TO 30 MPH. THIS HAS LEAD TO WIND CHILLS DROPPING INTO THE 20 TO 30 DEGREES BELOW ZERO RANGE. WITH TEMPERATURES NOT EXPECTED TO CLIMB MUCH AT ALL...WILL BE ISSUING A WIND CHILL ADVISORY FOR PORTIONS OF SE MN/NE IA THROUGH THIS AFTERNOON. HAVE ALSO ADDED A FEW COUNTIES IN NORTHWEST WISCONSIN TO THE ADVISORY AND STARTED THE NORTH CENTRAL COUNTIES RIGHT NOW AS WELL SINCE TEMPERATURES ARE GOING TO CONTINUE TO DROP THERE AS WELL. EXACT COUNTIES/TIMING IS CURRENTLY BEING WORKED ON WITH NEIGHBORING OFFICES AND THE ADVISORY SHOULD BE POSTED SHORTLY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND POTENTIAL FOR MORE SNOW LATER TONIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3 SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE -25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL. FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW FALLING JUST AHEAD OF THE SHORTWAVE. A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z. WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE AHEAD AND ISSUED AN ADVISORY FOR THEM. THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR PRECIPITATION THROUGHOUT. SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT. ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH 850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING... SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA. NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND. JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10 APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20 PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY 00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO WEDNESDAY. FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND... THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT... TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1151 AM CST MON DEC 9 2013 THE COMBINATION OF GUSTY WINDS AND A FRESH SNOW PACK HAS RESULTED IN SOME BLOWING SNOW IN SOUTHEAST MINNESOTA. THIS HAS CAUSED VISIBILITIES TO DROP AT RST TO 2-3SM THIS MORNING AND THAT WILL LIKELY CONTINUE INTO THE AFTERNOON BEFORE WINDS DROP OFF AROUND SUNSET. SOME SCT-BKN MVFR CEILINGS HAVE BEEN OCCURRING ACROSS WESTERN WISCONSIN AS TIMES AS WELL WITH LSE SEEMING TO BE ON THE WESTERN EDGE OF IT. WINDS WILL START TO COME AROUND TO THE SOUTHWEST THIS EVENING AS THE NEXT SYSTEM APPROACHES FROM THE WEST. CEILINGS AND VISIBILITY WILL DROP TO MVFR/IFR AS THE NEXT SNOW BAND COMES IN OVERNIGHT. THE BEST TIMING FOR THIS SNOW APPEARS TO BE AROUND 9Z AT RST AND 11Z AT LSE AND SHOULD ONLY LAST FOR 2-4 HOURS AS THIS SYSTEM QUICKLY MOVES THROUGH. WINDS WILL SHIFT BACK AROUND TO THE WEST NORTHWEST AND BECOME GUSTY AGAIN AT 20-30KTS. THIS WILL LIKELY LEAD TO SOME MORE BLOWING SNOW AND VISIBILITY REDUCTIONS AT RST TOMORROW MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ032>034. WIND CHILL ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ017-029. MN...WIND CHILL ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079- 086>088-094-095. IA...WIND CHILL ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008-009- 018-019. && $$ UPDATE...HALBACH SHORT TERM...AJ LONG TERM...AJ AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1044 AM CST MON DEC 9 2013 .UPDATE... ISSUED AT 1044 AM CST MON DEC 9 2013 TEMPERATURES HAVE NOT RISEN ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA THIS MORNING WHILE WINDS HAVE CONTINUED TO INCREASE TO AROUND 20 TO 30 MPH. THIS HAS LEAD TO WIND CHILLS DROPPING INTO THE 20 TO 30 DEGREES BELOW ZERO RANGE. WITH TEMPERATURES NOT EXPECTED TO CLIMB MUCH AT ALL...WILL BE ISSUING A WIND CHILL ADVISORY FOR PORTIONS OF SE MN/NE IA THROUGH THIS AFTERNOON. HAVE ALSO ADDED A FEW COUNTIES IN NORTHWEST WISCONSIN TO THE ADVISORY AND STARTED THE NORTH CENTRAL COUNTIES RIGHT NOW AS WELL SINCE TEMPERATURES ARE GOING TO CONTINUE TO DROP THERE AS WELL. EXACT COUNTIES/TIMING IS CURRENTLY BEING WORKED ON WITH NEIGHBORING OFFICES AND THE ADVISORY SHOULD BE POSTED SHORTLY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND POTENTIAL FOR MORE SNOW LATER TONIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3 SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE -25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL. FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW FALLING JUST AHEAD OF THE SHORTWAVE. A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z. WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE AHEAD AND ISSUED AN ADVISORY FOR THEM. THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 352 AM CST MON DEC 9 2013 MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR PRECIPITATION THROUGHOUT. SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT. ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH 850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING... SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA. NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND. JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10 APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20 PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY 00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO WEDNESDAY. FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND... THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT... TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 542 AM CST MON DEC 9 2013 VFR TO MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES TODAY. GUSTY WEST WINDS OF 14 TO 18 KTS WITH GUSTS AROUND 24KTS WILL LEAD TO SOME PATCHY BLOWING SNOW...POSSIBLY REDUCING VISIBILITIES TO AROUND 5SM AT TIMES. SOUTH/SOUTHWEST WINDS WILL INCREASE LATE TONIGHT AHEAD OF A WEAK SYSTEM APPROACHING FROM THE NORTHERN PLAINS. LOOK FOR WINDS TO INCREASE INTO THE 14 TO 18 KT RANGE AGAIN WITH GUSTS AROUND 25 KTS POSSIBLE. SOME PATCHY BLOWING SNOW MAY OCCUR AGAIN LATE TONIGHT AS THE WINDS INCREASE. LIGHT SNOW OR FLURRIES WILL MOVE ACROSS THE TAF SITES MAINLY AFTER 10Z TONIGHT. A BRIEF PERIOD OF MVFR OR POSSIBLY IFR CONDITIONS MAY OCCUR AS THE SNOW MOVES THROUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY FOR WIZ017-029. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP