Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 11/18/11
AREA FORECAST DISCUSSION
NWS DENVER CO
1149 PM MST TUE NOV 15 2011
.UPDATE...
&&
.SHORT TERM...WINDS IN THE DENVER METRO AREA JUST SHIFTED TO A
NORTHERLY DIRECTION WITH PASSAGE OF A WEAK FRONTAL BOUNDARY WHICH
IS BEING PUSHED SOUTHWARD BY 2-3MB PRESSURE RISE COUPLET ALONG
THE COLORADO/WYOMING BORDER. WIND SPEEDS IMMEDIATELY BEHIND THIS
BOUNDARY IN THE 10-20KT RANGE. WIND SHIFT/SURGE NOT HANDLED WELL
BY THE MODELS EXCEPT FOR THE RUC. ALTHOUGH THE RUC WAS A BIT
PREMATURE TO MOVE THIS WIND SHIFT THROUGH THE METRO AREA. AT ANY
RATE...UPDATED WIND AND WIND GUST GRIDS OUT TO 18Z USING THE
LATEST RUC AND HRRR MODEL RUNS TO ACCOUNT FOR THE CURRENT WIND
SHIFT AND TO REFLECT THE NORTHERLY WIND PATTERN EXPECTED ON THE
PLAINS DURING THE DAY.
.AVIATION...JUST UPDATED DENVER AREA TERMINAL FORECASTS TO REFLECT
THE SHIFT THE NORTHERLY WINDS WITH PASSAGE OF A WEAK FRONTAL
BOUNDARY. NEXT FEW HOURS SHOULD SEE WINDS IN THE METRO AREA
ASSUMING A SOMEWHAT TYPICAL DRAINING PATTERN...ONLY TO SWING
AROUND TO A NORTHERLY COMPONENT AROUND MID-MORNING WITH HEATING
AND MIXING.
&&
.PREV DISCUSSION... /ISSUED 952 PM MST TUE NOV 15 2011/
UPDATE...
SHORT TERM...JET RELATED LIFT HAS RESOLVED INTO TWO SHOWER BANDS.
THE MAIN ONE IS NOW FROM SOUTHERN SUMMIT COUNTY OUT TO WASHINGTON
COUNTY WHILE A WEAKER ONE HAS DEVELOPED ON THE BACK EDGE OF THE
CLOUD DECK FROM NEAR STEAMBOAT SPRINGS INTO LARIMER COUNTY.
DOWNSLOPE WINDS ARE STILL ENOUGH TO KILL THE SHOWERS ALONG THE
EAST SLOPES...AND LOW LEVELS ARE STILL PRETTY DRY TOO...SO I
EXPECT THAT WE ARE SEEING MAINLY FLURRIES ON THE PLAINS AND JUST
LIGHT SHOWERS IN THE MOUNTAINS. COULD SEE AN INCH OR TWO WHERE THE
SHOWERS ARE TRAINING I SUPPOSE. INCOMING AIR WAS A BIT
COLDER/DRIER THAN EXPECTED SO DROPPED TEMPS ABOUT 4 DEGREES
TONIGHT. AREAS THAT CLEARED EARLIER WILL HAVE CLOUDS FOR A WHILE...BUT
COULD STILL DROP EVEN COLDER IN THE NORTHERN/WESTERN PARTS OF THE
AREA IF IT CLEARS AGAIN BEFORE MORNING.
AVIATION...VFR CONDITIONS AS WEAK SHOWERS STAY AWAY FROM THE
DENVER AREA...NO CHANGES NEEDED.
PREV DISCUSSION... /ISSUED 305 PM MST TUE NOV 15 2011/
SHORT TERM...LATEST Q-G ANALYSIS SHOWS DEEP BUT WEAK LIFT OVER THE
FORECAST AREA. SOME OF THIS LIFT IS LIKELY ASSOCIATED WITH THE
RIGHT REAR ENTRANCE REGION OF THE DEPARTING UPPER LEVEL JET.
MEANWHILE...ANOTHER SPEED MAX WAS MOVING TOWARD THE FOUR CORNERS
AREA AND THERE IS ALSO A MODEST AMOUNT OF FRONTOGENESIS DEPICTED
ACROSS THE EASTERN PLAINS TONIGHT. THIS SHOULD KEEP AT LEAST WEAK
LIFT GOING THROUGH THE NIGHT. AT THE SAME TIME...AIRMASS WILL
SLOWLY DESTABILIZE WITH COLD ADVECTION ALOFT. WE ARE STILL A LITTLE
SKEPTICAL OF THE MOISTURE SHOWN...ESPECIALLY WITH THE GFS WHICH
SEEMS TO AGGRESSIVE WITH AVAILABLE MOISTURE AND THUS PRECIPITATION
AMOUNTS OVER THE PLAINS. WE WILL LEAN TOWARD THE NAM AND LATEST RUC
SOLUTIONS TONIGHT WHICH ARE MORE CONSERVATIVE OVER EAST CENTRAL
COLORADO. WE ALSO KEEP THE CHANCE OF PRECIPITATION CONFINED TO THE
PALMER DIVIDE AREA EASTWARD TOWARD AKRON AND LIMON TONIGHT BASED ON
THIS AREA BEING UNDER THE BEST LIFT...MID LEVEL CONVERGENCE...AND
FRONTOGENESIS.
IN THE MOUNTAINS...SNOW SHOWERS WILL CONTINUE TONIGHT BUT MOISTURE
DEPTH IS QUITE LIMITED. A FEW SPOTS HAVE PICKED UP AN INCH OR TWO
TODAY BASED ON THE SNOTEL DATA...AND EXPECT SIMILAR AMOUNTS TONIGHT.
BY WEDNESDAY...AIRMASS WILL BE DRYING WITH SNOW SHOWERS COMING TO AN
END IN THE MOUNTAINS. MOSTLY SUNNY SKIES SHOULD PREVAIL ON THE
PLAINS WITH LARGE SCALE SUBSIDENCE IN PLACE. WINDS WILL ALSO BE
LIGHTER IN MOST LOCATIONS.
LONG TERM...FAST ZONAL FLOW LOOKS LIKE IT WILL CONTINUE ACROSS THE
COUNTRY FOR MOST OF THE UPCOMING WEEK. THE POLAR JET STREAM WILL
MIGRATE BACK AND FORTH OVER THE STATE AT TIMES THROUGH THE FORECAST
PERIOD AS THE ZONAL FLOW ALOFT CONTINUES. RIPPLES EMBEDDED IN THE
ZONAL FLOW WILL BRING PERIODS OF SNOW TO THE MOUNTAINS AND GUSTY
WINDS OVER THE CONTINENTAL DIVIDE AND EAST SLOPES. THE FIRST MAIN
JET WILL BE PASSING OVERHEAD WEDNESDAY NIGHT...BRINGING THE FIRST
EPISODE OF GUSTY WINDS TO THE FOOTHILLS TOMORROW NIGHT. STRONG
WINDS ARE EXPECTED TO REMAIN UP OVER THE HIGHER TERRAIN SINCE HIGH
PRESSURE OVER KANSAS WILL INITIALLY PRODUCE SOUTHEASTERLY FLOW
ACROSS THE NORTHEAST COLORADO PLAINS. SPEEDS ALSO APPEAR TO NOT BE
STRONG ENOUGH TO WARRANT ANY HIGHLIGHTS FOR NOW.
ON THURSDAY NIGHT...THE RIGHT EXIT REGION OF ANOTHER UPPER JET WILL
BE MOVING IN FROM THE WEST. THIS WILL PRODUCE ANOTHER PERIOD OF
GUSTY WINDS WHICH MIGHT WORK THEIR WAY DOWN THE EASTERN FOOTHILL
SLOPES. BY FRIDAY...THE ECMWF AND GFS SHOW A SHORT WAVE TROUGH
APPROACHING COLORADO WHICH WILL SPREAD SNOW INTO THE MOUNTAINS.
THIS TROUGH WILL BE ACCOMPANIED BY A COMPLICATED UPPER LEVEL JET
STRUCTURE...HELPING TO ENHANCE SNOWFALL OVER THE NORTHWEST PART OF
THE STATE. BY SATURDAY MORNING...THE MODELS SHOW THIS TROUGH
SHEARING OUT OVER THE CENTRAL PART OF THE STATE BEFORE PRODUCING ANY
PRECIPITATION OVER THE NORTHEAST COLORADO PLAINS. THE STATE WILL
CONTINUE UNDER STRONG SOUTHWESTERLY FLOW ALOFT THROUGH THE REST OF
THE WEEKEND AS AN UPPER LOW CUTS OFF ALONG THE CALIFORNIA COAST.
THIS UPPER LOW IS FORECAST TO BE MOVING TOWARDS COLORADO BY
TUESDAY...WITH MOST OF ITS PRECIPITATION OCCURRING OVER NEW MEXICO
AND SOUTHERN COLORADO. ALL IN ALL...AN ACTIVE WEATHER PATTERN BUT
WITHOUT ENOUGH WIND OR PRECIPITATION TO WARRANT ANY HIGHLIGHTS FOR
NOW.
AVIATION...ANTICYCLONIC LOW LEVEL FLOW IS STILL MAKING FOR A TRICKY
WIND FORECAST THIS EVENING...ALTHOUGH WINDS WILL TREND MORE
EAST/SOUTHEASTERLY AND EVENTUALLY RETURN TO NORMAL DIURNAL SOUTHERLY
FLOW AFT 06Z TONIGHT. THERE IS JUST A SLIGHT RISK OF A PASSING SNOW
SHOWER IN THE AREA BUT AT THIS TIME MAIN CHANCE WOULD REMAIN TO THE
SOUTH AND EAST OF THE FRONT RANGE AIRPORTS AND AFFECT THE SOUTHEAST
APPROACH GATES AROUND LIMON FROM 01Z-10Z. VISUAL LANDING CONDITIONS
SHOULD PREVAIL WITH ONLY A SLIGHT RISK OF CEILINGS DROPPING BELOW
6000 FT AGL BETWEEN 00Z AND 06Z. ON WEDNESDAY...LOOK FOR ONLY
FEW-SCT CLOUDS ABOVE 7000 FT AND WINDS BECOMING NORTH/NORTHEAST
10-15 KTS AROUND 18Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER/GIMMESTAD/BARJENBRUCH
LONG TERM....DANKERS
AVIATION...BAKER/GIMMESTAD/BARJENBRUCH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1202 AM EST WED NOV 16 2011
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
WEATHER CONDITIONS WILL BE FLUCTUATING QUITE A BIT OVER THE NEXT
SEVERAL DAYS. FIRST...ANOTHER COLD FRONT WILL MOVE ACROSS CENTRAL
INDIANA TONIGHT BRINGING MUCH COLDER AIR BEHIND IT. HIGHS WILL
ONLY TOP OFF IN THE 40S THE NEXT FEW DAYS DESPITE THE DRY
CONDITIONS. THE NEXT CHANCE FOR PRECIP AND ISOLATED THUNDERSTORMS
WILL BE LATE IN THE WEEKEND AS A RATHER STRONG SYSTEM MOVES ACROSS
CENTRAL INDIANA. FURTHER OUT...HIGH PRESSURE WILL RE-ESTABLISH
ITSELF OVER CENTRAL INDIANA LATE MONDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
SO FAR CURRENT FORECAST SEEMS TO BE ON TRACK. PRESENTLY RAIN
OCCURRING SOUTH OF OHIO RIVER...BUT RADAR LOOPS INDICATE THAT IT HAS
PUSHED NORTH INTO MISSOURI BOOTHEEL AS UPPER LEVEL DISTURBANCE
MOVING ACROSS ARKANSAS AND TENNESSEE. RUC BRINGS PRECIPITATION
ACROSS OUR FAR SOUTH LATE TONIGHT AND EARLY WEDNESDAY...BUT NOTHING
MUCH NORTH OF OUR SOUTHERN ROW OF COUNTIES.
I HAVE ADJUSTED RAIN AREA SLIGHTLY SOUTH OVERNIGHT...BUT NOT ENOUGH
TO UPDATE FORECAST PRODUCTS. ONE MINOR CHANGE IN GRIDS WILL BE TO
SLOW DOWN FALL OF TEMPERATURES A LITTLE OVERNIGHT UNTIL SECONDARY
COLD FRONT MOVES THROUGH LATE TONIGHT. BUT EVEN THERE THE OVERNIGHT
LOWS STILL SEEM TO BE ON TRACK WITH MID TO UPPER 30S ACROSS OUR
NORTHWEST AND LOWER TO MID 40S SOUTH.
&&
.SHORT TERM /TOMORROW THROUGH THURSDAY/...
THE MAIN FOCUS OF THE SHORT TERM IS TEMPS.
MUCH COOLER TEMPS AND DRY CONDITIONS WILL PREVAIL TOMORROW IN THE
WAKE OF A COLD FRONT. HIGHS WILL ONLY TOP OFF IN THE UPPER
40S/LOWER 50S ACROSS THE SOUTHERN COUNTIES...AND MID 40S TO THE
NORTH. MODELS SEEM TO HAVE A GOOD HANDLE ON THE COLD
ADVECTION...SO WENT WITH ALLBLEND. TOMORROW NIGHT...TRENDED ON THE
WARMER SIDE OF GUIDANCE AS CLOUDS BUILD INTO THE AREA AHEAD OF A
BROAD UPPER LEVEL LOW. GUIDANCE IS SHOWING LOWS IN THE MID TO UPPER
20S...SO WENT WITH UPPER 20S/LOW 30S. HOWEVER...CONFIDENCE IS LOW
SINCE 850MB TEMPS ARE HINTING AT A COOLING TREND.
THURSDAY...WENT ABOVE GUIDANCE SINCE WINDS WILL BE BACKING TO THE
WEST THROUGH THE COURSE OF THE DAY. THIS MAY BE TOO OPTIMISTIC
THOUGH...SO CONFIDENCE IS A BIT LOW. FOR NOW...HAVE HIGHS OF LOW
TO MID 40S OVER THE NORTH...AND UPPER 40S ACROSS THE SOUTHERN
PORTIONS OF CENTRAL INDIANA. THURSDAY NIGHT...JUST WENT WITH A
BLEND OF UPPER 20S/LOW 30S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE HAVING TIMING DIFFICULTIES WITH A STRONG FRONTAL SYSTEM
THAT IS EXPECTED TO IMPACT CENTRAL INDIANA THIS WEEKEND INTO EARLY
NEXT WEEK. THE 12Z ECMWF AND 12Z GEM ARE BOTH QUITE A BIT FASTER
THAN THE 12Z GFS. THE 12Z GFS ESEMBLE MEANS WERE IN BETWEEN...BUT
THE ESEMBLES HAD LARGE STANDARD DEVIATIONS. SO...AT THIS POINT...A
NON-GFS BLEND LOOKS GOOD. HAD TO MAKE SEVERAL CHANGES TO THE
INITIALIZATION EXTENDED REGARDING TIMING OF THE RAIN. DROPPED SLIGHT
CHANCE POPS NORTHWEST ON FRIDAY WITH THE FRONTAL SYSTEM WELL TO THE
WEST ACROSS THE ROCKIES. OTHERWISE...THE FRONT IS EXPECTED TO SLIDE
ACROSS SATURDAY NIGHT. MODELS SUGGEST SYSTEM STRONG ENOUGH TO
PRODUCE A FEW THUNDERSTORMS AS WELL AS SHOWERS SATURDAY AND SATURDAY
NIGHT. THE 12Z ECMWF ALSO WAS SHOWING A WAVE LIFTING NORTHEAST ALONG
THE OSCILLATING FRONT NEAR THE OHIO RIVER ON MONDAY WHICH JUSTIFIES
KEEPING POPS IN THROUGH THEN. FINALLY...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT ON MONDAY NIGHT WHICH SHOULD DRY THINGS OUT BY
TUESDAY AND ALLOW FOR MUCH COOLER TEMPERATURES ONLY IN THE 40S FOR
AFTERNOON HIGHS IN CONTRAST TO HIGHS IN THE 50S AND POSSIBLY 60S
SATURDAY IN THE RETURN FLOW AHEAD OF THE FRONT. AFTER COORDINATING
WITH ADJACENT OFFICES...PULLED THE INITIALIZATION EXTENDED POPS.
&&
.AVIATION /DISCUSSION FOR THE 16/06Z TAFS/...
CEILINGS AT SOME LOCATIONS /HUF AND BMG ESPECIALLY/ HAVE AT LEAST
TEMPORARILY DROPPED INTO IFR CATEGORY...AND MAY REMAIN THERE UNTIL
THE SECONDARY FRONT PASSES EARLY THIS MORNING. SREF PROBABILITIES
INDICATE MVFR/IFR SHOULD END AT HUF/IND AROUND 09Z...LASTING AT BMG
THROUGH MID MORNING.
SOME CONCERN ABOUT FOG OR LIFR CEILINGS WITH SLOW MOVING BOUNDARY IN
PROXIMITY TO SITES...AND SOME UNSETTLINGLY LOW TEMP/DEWPOINT
SPREADS...BUT NO GUIDANCE INDICATES THIS AS A SIGNIFICANT
POTENTIAL...AND WITH BOUNDARY MAKING SLOW BUT STEADY PROGRESS...WILL
LEAVE OUT. WILL REQUIRE MONITORING...ESPECIALLY NEAR SUNRISE AT ALL
SITES.
WINDS FROM MID MORNING THROUGH THIS EVENING WILL BE NORTHERLY...AND
GUSTY INTO THE MID TO HIGH TEENS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...JH
SHORT TERM...TDUD
LONG TERM....50
AVIATION...NIELD/50
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1010 AM MST WED NOV 16 2011
.DISCUSSION...
301 AM MST WED NOV 16 2011
FORECAST PROBLEMS WILL BE TODAY...AND THEN HOW FAST IS THE
TEMPERATURE RECOVERY INTO FRIDAY. SATELLITE SHOWING SOME
AMPLIFICATION TO THE FLOW FROM THE WESTERN PACIFIC INTO CENTRAL NORTH
AMERICA. UPPER TROUGH IS STILL HANGING AROUND OVER THE CENTRAL
PORTION OF THE COUNTRY WITH NUMEROUS SHORTWAVE TROUGHS MOVING THROUGH
IT. COLD FRONT THAT WENT THROUGH EARLIER TODAY EXTENDS FROM THE
SOUTHERN PLAINS TO ALONG THE FRONT RANGE OF COLORADO.
MODELS INITIALIZED FINE AT JET LEVEL. MODELS INITIALIZED FINE AT MID
LEVELS EXCEPT THE GFS WAS TOO MOIST. THE MODELS TENDED TO BE
SLIGHTLY TOO FAR EAST AND SOUTH WITH THE SURFACE RIDGE AND THE LEE
SURFACE TROUGH. HOWEVER...THE NAM WAS PRETTY CLOSE AND SLIGHTLY
BETTER THAN THE ECMWF. ON THE LOW LEVEL THERMAL FIELD OVERALL...THE
CANADIAN...GFS AND UKMET WERE ABOUT THE SAME AND A LITTLE BETTER
WITH THE NAM NOT TOO FAR BEHIND AND MAYBE BETTER TO THE NORTH OF THE
AREA.
TODAY/TONIGHT...INITIAL PROBLEM WILL BE COVERAGE AND DURATION OF
SNOWFALL THIS MORNING AS A SHORTWAVE TROUGH AND LIFT FROM THE
UPPER JET MOVE THROUGH. GOING BY THE DNR 00Z SOUNDING...THE BEST
MOISTURE IS ABOVE 700 MB AND REALITY IS SUPPORTING THAT. SO FAR
VISIBILITIES/OBSERVATIONS AND CAMERAS SHOW LITTLE IF ANY
ACCUMULATION...EVEN UNDER THE MOST INTENSE BAND THAT IS ALONG THE
KANSAS AND NEBRASKA BORDER. TEMPERATURE AND DEWPOINT SPREADS ARE
LARGE...ESPECIALLY IN THE NORTH WHERE THE RADAR SAYS THE MOST INTENSE
PRECIPITATION IS. MOST OF THE MODELS SAY THAT MEASURABLE SHOULD BE
OCCURRING AT THIS TIME WITH RUC HAVING THE LEAST MEASURABLE AND
LOOKING THE BEST AT THIS TIME.
RIGHT REAR QUADRANT SHOULD BE EAST OF THE AREA BY 12Z. 7-5H
SHORTWAVE LOOKS TO BE ENTERING THE WESTERN PORTION OF THE FORECAST
AREA AT THIS TIME. SOME PV MOVES ACROSS EARLY WITH THE BRUNT OF IT
NORTH. DOWNGLIDE ALSO MOVES IN RATHER QUICKLY THIS MORNING. WILL
CONTINUE TO WATCH TRENDS FOR CHANGES BUT PLAN ON TAKING THE
MEASURABLE OUT AND HAVE FLURRIES OVER MOST OF THE AREA THIS MORNING
WITH MAYBE A LITTLE LINGERING IN THE FAR EAST INTO THE EARLY
AFTERNOON.
QUESTION THEN BECOMES HOW FAST WE CLEAR OUT AND ITS AFFECT ON HIGH
TEMPERATURES. STRONG JET ON THE BACKSIDE OF THE UPPER TROUGH DOES
NOT GET CLOSE TO THE AREA UNTIL LATE IN THE DAY. BASED ON
SATELLITE...WE SHOULD CLEAR OUT RATHER QUICKLY WITH THE MODELS
LOOKING LIKE THEY ARE HANGING ONTO CLOUDS A LITTLE TOO LONG.
CURRENTLY TEMPERATURES ARE RUNNING A LITTLE WARMER THAN DEPICTED
BUT CLEARING AND TEMPERATURES UPSTREAM SUPPORT MINS GETTING NEAR
WHAT IS CALLED FOR. MODEL GUIDANCE IS SIMILAR IN ITS DEPICTION AND
MADE SLIGHT ADJUSTMENTS BASED ON LATEST TRENDS/GUIDANCE.
ANOTHER CONCERN WILL BE WINDS ON THE BACKSIDE OF THE SYSTEM AS IT
EXITS. LOOKS LIKE WILL HAVE GOOD SUBSIDENCE AND ADIABATIC LAPSE
RATES. SO IT LOOKS LIKE WE WILL SEE A BRIEF PERIOD OF AT LEAST
BREEZY AND GUSTY WINDS THIS AFTERNOON BUT DO NOT SEE ANYTHING
GETTING OUT OF HAND.
JET AXIS MOVES ACROSS THE AREA DURING THE NIGHT...AND AFFECTS THE
NORTHEAST HALF OF THE AREA BY 12Z. THAT AND ANOTHER SHORTWAVE
WILL INCREASE THE CLOUDS AFTER 06Z. NEXT QUESTION WILL BE HOW FAST
THE SURFACE MOVES THROUGH AND HOW FAST DO THE WINDS INCREASE. LIKE
THE SLIGHTLY SLOWER EVOLUTION AND THINK THE GFS IS TOO FAST. AT
THIS TIME...IT LOOKS LIKE TEMPERATURES WILL BOTTOM OUT EARLY...
ESPECIALLY IN THE WEST AND THEN REMAIN STEADY AFTER THAT.
THURSDAY/THURSDAY NIGHT...RIGHT REAR QUADRANT OF THE JET REMAINS
NEAR OR OVER THE AREA THROUGH THE DAY. SOME DIFFERENCE IN THE AMOUNT
OF CLOUD COVER WITH MOST OF THE MODELS SHOWING A MOSTLY SUNNY TO
A PARTLY SUNNY DAY. AS HAS BEEN THE CASE IN THIS FLOW...CLOUDS
MAY BE A LITTLE MORE THAN CURRENTLY THINK. SHOULD START OFF WITH
DOWNSLOPE WINDS BUT THEN THEY SHIFT TO THE SOUTH AS LEE TROUGH
STRENGTHENS. MODELS DO NOT LOOK AS STRONG ON THE WINDS AS YESTERDAY
AS MIXING AND GRADIENT ARE NOT AS STRONG AS PREVIOUSLY DEPICTED.
STRONGEST WINDS WILL BE IN THE EAST. SOME DIFFERENCES IN THE DEPICTED
MAXES. THE 06Z NAM HAS COOLED THINGS OFF A LITTLE FROM 00Z. AT THIS
TIME...WILL TREND TOWARD THE WARMER SIDE OF THE GUIDANCE.
FRIDAY/FRIDAY NIGHT...COMPLEX JET SETUP BEGINS DURING THE DAY.
NORTHERN STREAM REMAINS WELL NORTHWEST OF THE AREA THROUGH THE DAY.
HOWEVER...LEFT FRONT QUADRANT OF A SOUTHERN JET DEVELOPS OR
STRENGTHENS OVER THE AREA THROUGH THE DAY...ESPECIALLY IN THE
AFTERNOON. THERE LOOKS TO BE SOME INCREASING HIGH CLOUDS IN THE
AFTERNOON. CONSIDERING WHAT THE JET IS DOING AND THE STRONG
SOUTHWESTERLY FLOW...LIKE WHAT THE NAM AND ECMWF ARE SHOWING WITH A
STRENGTHENING AND FURTHER WEST LEE TROUGH. THIS MEANS LESS OF A
DOWNSLOPE COMPONENT AND IF MODELS ARE CORRECT MORE OF AN EASTERLY
COMPONENT AS THE DAY WHERES ON. SO WILL TREND TOWARD THE COOLER
SIDE OF GUIDANCE.
AS A SIDE NOTE...DUE TO A MORE EASTERLY WIND AND HIGHER DEWPOINTS...
BELIEVE SHOULD NOT SEE ANY FIRE WEATHER CONCERNS DESPITE THE WARMER
TEMPERATURES.
BULLER
FOR THE PERIOD SATURDAY THROUGH TUESDAY...SHORTWAVE WILL EJECT
ACROSS THE CENTRAL PLAINS SATURDAY FROM BASE OF WEST COAST MEAN
TROUGH. TRACK OF THE UPPER SYSTEM AND MOISTURE PROFILES SUGGEST FROPA
WILL BE DRY. THERE MAY BE A PERIOD OF GUSTY NORTH WINDS BEHIND THE
FRONT SOMETIME ON SATURDAY. COLDER TEMPERATURES WILL FOLLOW ON
SUNDAY...LOW TO MIDDLE 40S FOR HIGHS...WHICH IS AROUND 10 DEGREES
BELOW NORMAL. RETURN FLOW GETS UNDER WAY FOR MONDAY UNDER SHORTWAVE
RIDGING ALOFT WITH TEMPERATURES WARMING TO NEAR NORMAL AND CONTINUED
DRY. REMNANTS OF WEST COAST SYSTEM COMES ACROSS SOUTHERN ROCKIES ON
TUESDAY BRINGING A CHANCE OF MAINLY RAIN...BEST CHANCES WILL BE
SOUTH. 024
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
1010 AM MST WED NOV 16 2011
FOR THE 18Z TAFS...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE
EFFECTIVE TAF PERIOD AT BOTH KGLD AND KMCK. MVFR CIGS/VIS ASSOCIATED
WITH LINGERING LIGHT SNOW OVER KMCK CURRENTLY EXPECTED TO IMPROVE TO
VFR BY 18Z BASED ON CURRENT RADAR/SATELLITE TRENDS. WILL CONTINUE TO
MONITOR TRENDS UP TO TAF ISSUANCE IN THE EVENT SNOW IS SLOWER TO
MOVE EAST OF THE TERMINAL. GUSTY NORTHWEST WINDS STILL EXPECTED TO
DEVELOP THIS AFTERNOON BEHIND DEPARTING SHORTWAVE TROUGH...BEFORE
DECREASING AROUND 00Z AS SURFACE HIGH PRESSURE SETTLES IN OVER THE
REGION AND DAYTIME MIXING COMES TO AN END. WINDS WILL INCREASE TO
12-14KT FROM THE WEST TO THE EAST 09-12Z THU IN RESPONSE TO LEE
TROUGH DEVELOPMENT OVER EASTERN COLORADO.
DR
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
604 AM MST WED NOV 16 2011
.UPDATE...
601 AM MST WED NOV 16 2011
JUST COMPLETED AN UPDATE. PERSISTENT BANDS CONTINUE OVER NORTHERN
AND EASTERN SECTIONS...AND ARE PRODUCING MORE THAN FLURRIES. MOST
INTENSE BAND IS OVER NORTHERN SECTIONS AT THIS TIME. SO INCREASED
POPS IN THOSE AREAS. ALSO INCREASED CLOUD COVER PER LATEST
SATELLITE AND UPDATED HOURLY TEMPERATURE...DEWPOINT...AND WIND
GRIDS FOR THIS MORNING.
BULLER
&&
.DISCUSSION...
301 AM MST WED NOV 16 2011
FORECAST PROBLEMS WILL BE TODAY...AND THEN HOW FAST IS THE
TEMPERATURE RECOVERY INTO FRIDAY. SATELLITE SHOWING SOME
AMPLIFICATION TO THE FLOW FROM THE WESTERN PACIFIC INTO CENTRAL NORTH
AMERICA. UPPER TROUGH IS STILL HANGING AROUND OVER THE CENTRAL
PORTION OF THE COUNTRY WITH NUMEROUS SHORTWAVE TROUGHS MOVING THROUGH
IT. COLD FRONT THAT WENT THROUGH EARLIER TODAY EXTENDS FROM THE
SOUTHERN PLAINS TO ALONG THE FRONT RANGE OF COLORADO.
MODELS INITIALIZED FINE AT JET LEVEL. MODELS INITIALIZED FINE AT MID
LEVELS EXCEPT THE GFS WAS TOO MOIST. THE MODELS TENDED TO BE
SLIGHTLY TOO FAR EAST AND SOUTH WITH THE SURFACE RIDGE AND THE LEE
SURFACE TROUGH. HOWEVER...THE NAM WAS PRETTY CLOSE AND SLIGHTLY
BETTER THAN THE ECMWF. ON THE LOW LEVEL THERMAL FIELD OVERALL...THE
CANADIAN...GFS AND UKMET WERE ABOUT THE SAME AND A LITTLE BETTER
WITH THE NAM NOT TOO FAR BEHIND AND MAYBE BETTER TO THE NORTH OF THE
AREA.
TODAY/TONIGHT...INITIAL PROBLEM WILL BE COVERAGE AND DURATION OF
SNOWFALL THIS MORNING AS A SHORTWAVE TROUGH AND LIFT FROM THE
UPPER JET MOVE THROUGH. GOING BY THE DNR 00Z SOUNDING...THE BEST
MOISTURE IS ABOVE 700 MB AND REALITY IS SUPPORTING THAT. SO FAR
VISIBILITIES/OBSERVATIONS AND CAMERAS SHOW LITTLE IF ANY
ACCUMULATION...EVEN UNDER THE MOST INTENSE BAND THAT IS ALONG THE
KANSAS AND NEBRASKA BORDER. TEMPERATURE AND DEWPOINT SPREADS ARE
LARGE...ESPECIALLY IN THE NORTH WHERE THE RADAR SAYS THE MOST INTENSE
PRECIPITATION IS. MOST OF THE MODELS SAY THAT MEASURABLE SHOULD BE
OCCURRING AT THIS TIME WITH RUC HAVING THE LEAST MEASURABLE AND
LOOKING THE BEST AT THIS TIME.
RIGHT REAR QUADRANT SHOULD BE EAST OF THE AREA BY 12Z. 7-5H
SHORTWAVE LOOKS TO BE ENTERING THE WESTERN PORTION OF THE FORECAST
AREA AT THIS TIME. SOME PV MOVES ACROSS EARLY WITH THE BRUNT OF IT
NORTH. DOWNGLIDE ALSO MOVES IN RATHER QUICKLY THIS MORNING. WILL
CONTINUE TO WATCH TRENDS FOR CHANGES BUT PLAN ON TAKING THE
MEASURABLE OUT AND HAVE FLURRIES OVER MOST OF THE AREA THIS MORNING
WITH MAYBE A LITTLE LINGERING IN THE FAR EAST INTO THE EARLY
AFTERNOON.
QUESTION THEN BECOMES HOW FAST WE CLEAR OUT AND ITS AFFECT ON HIGH
TEMPERATURES. STRONG JET ON THE BACKSIDE OF THE UPPER TROUGH DOES
NOT GET CLOSE TO THE AREA UNTIL LATE IN THE DAY. BASED ON
SATELLITE...WE SHOULD CLEAR OUT RATHER QUICKLY WITH THE MODELS
LOOKING LIKE THEY ARE HANGING ONTO CLOUDS A LITTLE TOO LONG.
CURRENTLY TEMPERATURES ARE RUNNING A LITTLE WARMER THAN DEPICTED
BUT CLEARING AND TEMPERATURES UPSTREAM SUPPORT MINS GETTING NEAR
WHAT IS CALLED FOR. MODEL GUIDANCE IS SIMILAR IN ITS DEPICTION AND
MADE SLIGHT ADJUSTMENTS BASED ON LATEST TRENDS/GUIDANCE.
ANOTHER CONCERN WILL BE WINDS ON THE BACKSIDE OF THE SYSTEM AS IT
EXITS. LOOKS LIKE WILL HAVE GOOD SUBSIDENCE AND ADIABATIC LAPSE
RATES. SO IT LOOKS LIKE WE WILL SEE A BRIEF PERIOD OF AT LEAST
BREEZY AND GUSTY WINDS THIS AFTERNOON BUT DO NOT SEE ANYTHING
GETTING OUT OF HAND.
JET AXIS MOVES ACROSS THE AREA DURING THE NIGHT...AND AFFECTS THE
NORTHEAST HALF OF THE AREA BY 12Z. THAT AND ANOTHER SHORTWAVE
WILL INCREASE THE CLOUDS AFTER 06Z. NEXT QUESTION WILL BE HOW FAST
THE SURFACE MOVES THROUGH AND HOW FAST DO THE WINDS INCREASE. LIKE
THE SLIGHTLY SLOWER EVOLUTION AND THINK THE GFS IS TOO FAST. AT
THIS TIME...IT LOOKS LIKE TEMPERATURES WILL BOTTOM OUT EARLY...
ESPECIALLY IN THE WEST AND THEN REMAIN STEADY AFTER THAT.
THURSDAY/THURSDAY NIGHT...RIGHT REAR QUADRANT OF THE JET REMAINS
NEAR OR OVER THE AREA THROUGH THE DAY. SOME DIFFERENCE IN THE AMOUNT
OF CLOUD COVER WITH MOST OF THE MODELS SHOWING A MOSTLY SUNNY TO
A PARTLY SUNNY DAY. AS HAS BEEN THE CASE IN THIS FLOW...CLOUDS
MAY BE A LITTLE MORE THAN CURRENTLY THINK. SHOULD START OFF WITH
DOWNSLOPE WINDS BUT THEN THEY SHIFT TO THE SOUTH AS LEE TROUGH
STRENGTHENS. MODELS DO NOT LOOK AS STRONG ON THE WINDS AS YESTERDAY
AS MIXING AND GRADIENT ARE NOT AS STRONG AS PREVIOUSLY DEPICTED.
STRONGEST WINDS WILL BE IN THE EAST. SOME DIFFERENCES IN THE DEPICTED
MAXES. THE 06Z NAM HAS COOLED THINGS OFF A LITTLE FROM 00Z. AT THIS
TIME...WILL TREND TOWARD THE WARMER SIDE OF THE GUIDANCE.
FRIDAY/FRIDAY NIGHT...COMPLEX JET SETUP BEGINS DURING THE DAY.
NORTHERN STREAM REMAINS WELL NORTHWEST OF THE AREA THROUGH THE DAY.
HOWEVER...LEFT FRONT QUADRANT OF A SOUTHERN JET DEVELOPS OR
STRENGTHENS OVER THE AREA THROUGH THE DAY...ESPECIALLY IN THE
AFTERNOON. THERE LOOKS TO BE SOME INCREASING HIGH CLOUDS IN THE
AFTERNOON. CONSIDERING WHAT THE JET IS DOING AND THE STRONG
SOUTHWESTERLY FLOW...LIKE WHAT THE NAM AND ECMWF ARE SHOWING WITH A
STRENGTHENING AND FURTHER WEST LEE TROUGH. THIS MEANS LESS OF A
DOWNSLOPE COMPONENT AND IF MODELS ARE CORRECT MORE OF AN EASTERLY
COMPONENT AS THE DAY WHERES ON. SO WILL TREND TOWARD THE COOLER
SIDE OF GUIDANCE.
AS A SIDE NOTE...DUE TO A MORE EASTERLY WIND AND HIGHER DEWPOINTS...
BELIEVE SHOULD NOT SEE ANY FIRE WEATHER CONCERNS DESPITE THE WARMER
TEMPERATURES.
BULLER
FOR THE PERIOD SATURDAY THROUGH TUESDAY...SHORTWAVE WILL EJECT
ACROSS THE CENTRAL PLAINS SATURDAY FROM BASE OF WEST COAST MEAN
TROUGH. TRACK OF THE UPPER SYSTEM AND MOISTURE PROFILES SUGGEST FROPA
WILL BE DRY. THERE MAY BE A PERIOD OF GUSTY NORTH WINDS BEHIND THE
FRONT SOMETIME ON SATURDAY. COLDER TEMPERATURES WILL FOLLOW ON
SUNDAY...LOW TO MIDDLE 40S FOR HIGHS...WHICH IS AROUND 10 DEGREES
BELOW NORMAL. RETURN FLOW GETS UNDER WAY FOR MONDAY UNDER SHORTWAVE
RIDGING ALOFT WITH TEMPERATURES WARMING TO NEAR NORMAL AND CONTINUED
DRY. REMNANTS OF WEST COAST SYSTEM COMES ACROSS SOUTHERN ROCKIES ON
TUESDAY BRINGING A CHANCE OF MAINLY RAIN...BEST CHANCES WILL BE
SOUTH. 024
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
427 AM MST WED NOV 16 2011
FLURRIES WILL MOVE THROUGH THE REGION THIS MORNING BUT NOT EXPECTED
TO IMPACT FLIGHT CATEGORIES AT EITHER KGLD OR KMCK. NORTHWEST WINDS
WILL INCREASE BY THE AFTERNOON BEHIND DEPARTING SYSTEM WITH A FEW
GUSTS TO 25KTS BEFORE DIMINISHING AT SUNSET.
024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
427 AM MST WED NOV 16 2011
.DISCUSSION...
301 AM MST WED NOV 16 2011
FORECAST PROBLEMS WILL BE TODAY...AND THEN HOW FAST IS THE
TEMPERATURE RECOVERY INTO FRIDAY. SATELLITE SHOWING SOME
AMPLIFICATION TO THE FLOW FROM THE WESTERN PACIFIC INTO CENTRAL NORTH
AMERICA. UPPER TROUGH IS STILL HANGING AROUND OVER THE CENTRAL
PORTION OF THE COUNTRY WITH NUMEROUS SHORTWAVE TROUGHS MOVING THROUGH
IT. COLD FRONT THAT WENT THROUGH EARLIER TODAY EXTENDS FROM THE
SOUTHERN PLAINS TO ALONG THE FRONT RANGE OF COLORADO.
MODELS INITIALIZED FINE AT JET LEVEL. MODELS INITIALIZED FINE AT MID
LEVELS EXCEPT THE GFS WAS TOO MOIST. THE MODELS TENDED TO BE
SLIGHTLY TOO FAR EAST AND SOUTH WITH THE SURFACE RIDGE AND THE LEE
SURFACE TROUGH. HOWEVER...THE NAM WAS PRETTY CLOSE AND SLIGHTLY
BETTER THAN THE ECMWF. ON THE LOW LEVEL THERMAL FIELD OVERALL...THE
CANADIAN...GFS AND UKMET WERE ABOUT THE SAME AND A LITTLE BETTER
WITH THE NAM NOT TOO FAR BEHIND AND MAYBE BETTER TO THE NORTH OF THE
AREA.
TODAY/TONIGHT...INITIAL PROBLEM WILL BE COVERAGE AND DURATION OF
SNOWFALL THIS MORNING AS A SHORTWAVE TROUGH AND LIFT FROM THE
UPPER JET MOVE THROUGH. GOING BY THE DNR 00Z SOUNDING...THE BEST
MOISTURE IS ABOVE 700 MB AND REALITY IS SUPPORTING THAT. SO FAR
VISIBILITIES/OBSERVATIONS AND CAMERAS SHOW LITTLE IF ANY
ACCUMULATION...EVEN UNDER THE MOST INTENSE BAND THAT IS ALONG THE
KANSAS AND NEBRASKA BORDER. TEMPERATURE AND DEWPOINT SPREADS ARE
LARGE...ESPECIALLY IN THE NORTH WHERE THE RADAR SAYS THE MOST INTENSE
PRECIPITATION IS. MOST OF THE MODELS SAY THAT MEASURABLE SHOULD BE
OCCURRING AT THIS TIME WITH RUC HAVING THE LEAST MEASURABLE AND
LOOKING THE BEST AT THIS TIME.
RIGHT REAR QUADRANT SHOULD BE EAST OF THE AREA BY 12Z. 7-5H
SHORTWAVE LOOKS TO BE ENTERING THE WESTERN PORTION OF THE FORECAST
AREA AT THIS TIME. SOME PV MOVES ACROSS EARLY WITH THE BRUNT OF IT
NORTH. DOWNGLIDE ALSO MOVES IN RATHER QUICKLY THIS MORNING. WILL
CONTINUE TO WATCH TRENDS FOR CHANGES BUT PLAN ON TAKING THE
MEASURABLE OUT AND HAVE FLURRIES OVER MOST OF THE AREA THIS MORNING
WITH MAYBE A LITTLE LINGERING IN THE FAR EAST INTO THE EARLY
AFTERNOON.
QUESTION THEN BECOMES HOW FAST WE CLEAR OUT AND ITS AFFECT ON HIGH
TEMPERATURES. STRONG JET ON THE BACKSIDE OF THE UPPER TROUGH DOES
NOT GET CLOSE TO THE AREA UNTIL LATE IN THE DAY. BASED ON
SATELLITE...WE SHOULD CLEAR OUT RATHER QUICKLY WITH THE MODELS
LOOKING LIKE THEY ARE HANGING ONTO CLOUDS A LITTLE TOO LONG.
CURRENTLY TEMPERATURES ARE RUNNING A LITTLE WARMER THAN DEPICTED
BUT CLEARING AND TEMPERATURES UPSTREAM SUPPORT MINS GETTING NEAR
WHAT IS CALLED FOR. MODEL GUIDANCE IS SIMILAR IN ITS DEPICTION AND
MADE SLIGHT ADJUSTMENTS BASED ON LATEST TRENDS/GUIDANCE.
ANOTHER CONCERN WILL BE WINDS ON THE BACKSIDE OF THE SYSTEM AS IT
EXITS. LOOKS LIKE WILL HAVE GOOD SUBSIDENCE AND ADIABATIC LAPSE
RATES. SO IT LOOKS LIKE WE WILL SEE A BRIEF PERIOD OF AT LEAST
BREEZY AND GUSTY WINDS THIS AFTERNOON BUT DO NOT SEE ANYTHING
GETTING OUT OF HAND.
JET AXIS MOVES ACROSS THE AREA DURING THE NIGHT...AND AFFECTS THE
NORTHEAST HALF OF THE AREA BY 12Z. THAT AND ANOTHER SHORTWAVE
WILL INCREASE THE CLOUDS AFTER 06Z. NEXT QUESTION WILL BE HOW FAST
THE SURFACE MOVES THROUGH AND HOW FAST DO THE WINDS INCREASE. LIKE
THE SLIGHTLY SLOWER EVOLUTION AND THINK THE GFS IS TOO FAST. AT
THIS TIME...IT LOOKS LIKE TEMPERATURES WILL BOTTOM OUT EARLY...
ESPECIALLY IN THE WEST AND THEN REMAIN STEADY AFTER THAT.
THURSDAY/THURSDAY NIGHT...RIGHT REAR QUADRANT OF THE JET REMAINS
NEAR OR OVER THE AREA THROUGH THE DAY. SOME DIFFERENCE IN THE AMOUNT
OF CLOUD COVER WITH MOST OF THE MODELS SHOWING A MOSTLY SUNNY TO
A PARTLY SUNNY DAY. AS HAS BEEN THE CASE IN THIS FLOW...CLOUDS
MAY BE A LITTLE MORE THAN CURRENTLY THINK. SHOULD START OFF WITH
DOWNSLOPE WINDS BUT THEN THEY SHIFT TO THE SOUTH AS LEE TROUGH
STRENGTHENS. MODELS DO NOT LOOK AS STRONG ON THE WINDS AS YESTERDAY
AS MIXING AND GRADIENT ARE NOT AS STRONG AS PREVIOUSLY DEPICTED.
STRONGEST WINDS WILL BE IN THE EAST. SOME DIFFERENCES IN THE DEPICTED
MAXES. THE 06Z NAM HAS COOLED THINGS OFF A LITTLE FROM 00Z. AT THIS
TIME...WILL TREND TOWARD THE WARMER SIDE OF THE GUIDANCE.
FRIDAY/FRIDAY NIGHT...COMPLEX JET SETUP BEGINS DURING THE DAY.
NORTHERN STREAM REMAINS WELL NORTHWEST OF THE AREA THROUGH THE DAY.
HOWEVER...LEFT FRONT QUADRANT OF A SOUTHERN JET DEVELOPS OR
STRENGTHENS OVER THE AREA THROUGH THE DAY...ESPECIALLY IN THE
AFTERNOON. THERE LOOKS TO BE SOME INCREASING HIGH CLOUDS IN THE
AFTERNOON. CONSIDERING WHAT THE JET IS DOING AND THE STRONG
SOUTHWESTERLY FLOW...LIKE WHAT THE NAM AND ECMWF ARE SHOWING WITH A
STRENGTHENING AND FURTHER WEST LEE TROUGH. THIS MEANS LESS OF A
DOWNSLOPE COMPONENT AND IF MODELS ARE CORRECT MORE OF AN EASTERLY
COMPONENT AS THE DAY WHERES ON. SO WILL TREND TOWARD THE COOLER
SIDE OF GUIDANCE.
AS A SIDE NOTE...DUE TO A MORE EASTERLY WIND AND HIGHER DEWPOINTS...
BELIEVE SHOULD NOT SEE ANY FIRE WEATHER CONCERNS DESPITE THE WARMER
TEMPERATURES.
BULLER
FOR THE PERIOD SATURDAY THROUGH TUESDAY...SHORTWAVE WILL EJECT
ACROSS THE CENTRAL PLAINS SATURDAY FROM BASE OF WEST COAST MEAN
TROUGH. TRACK OF THE UPPER SYSTEM AND MOISTURE PROFILES SUGGEST FROPA
WILL BE DRY. THERE MAY BE A PERIOD OF GUSTY NORTH WINDS BEHIND THE
FRONT SOMETIME ON SATURDAY. COLDER TEMPERATURES WILL FOLLOW ON
SUNDAY...LOW TO MIDDLE 40S FOR HIGHS...WHICH IS AROUND 10 DEGREES
BELOW NORMAL. RETURN FLOW GETS UNDER WAY FOR MONDAY UNDER SHORTWAVE
RIDGING ALOFT WITH TEMPERATURES WARMING TO NEAR NORMAL AND CONTINUED
DRY. REMNANTS OF WEST COAST SYSTEM COMES ACROSS SOUTHERN ROCKIES ON
TUESDAY BRINGING A CHANCE OF MAINLY RAIN...BEST CHANCES WILL BE
SOUTH. 024
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
427 AM MST WED NOV 16 2011
FLURRIES WILL MOVE THROUGH THE REGION THIS MORNING BUT NOT EXPECTED
TO IMPACT FLIGHT CATEGORIES AT EITHER KGLD OR KMCK. NORTHWEST WINDS
WILL INCREASE BY THE AFTERNOON BEHIND DEPARTING SYSTEM WITH A FEW
GUSTS TO 25KTS BEFORE DIMINISHING AT SUNSET.
024
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
301 AM MST WED NOV 16 2011
.DISCUSSION...
301 AM MST WED NOV 16 2011
FORECAST PROBLEMS WILL BE TODAY...AND THEN HOW FAST IS THE
TEMPERATURE RECOVERY INTO FRIDAY. SATELLITE SHOWING SOME
AMPLIFICATION TO THE FLOW FROM THE WESTERN PACIFIC INTO CENTRAL NORTH
AMERICA. UPPER TROUGH IS STILL HANGING AROUND OVER THE CENTRAL
PORTION OF THE COUNTRY WITH NUMEROUS SHORTWAVE TROUGHS MOVING THROUGH
IT. COLD FRONT THAT WENT THROUGH EARLIER TODAY EXTENDS FROM THE
SOUTHERN PLAINS TO ALONG THE FRONT RANGE OF COLORADO.
MODELS INITIALIZED FINE AT JET LEVEL. MODELS INITIALIZED FINE AT MID
LEVELS EXCEPT THE GFS WAS TOO MOIST. THE MODELS TENDED TO BE
SLIGHTLY TOO FAR EAST AND SOUTH WITH THE SURFACE RIDGE AND THE LEE
SURFACE TROUGH. HOWEVER...THE NAM WAS PRETTY CLOSE AND SLIGHTLY
BETTER THAN THE ECMWF. ON THE LOW LEVEL THERMAL FIELD OVERALL...THE
CANADIAN...GFS AND UKMET WERE ABOUT THE SAME AND A LITTLE BETTER
WITH THE NAM NOT TOO FAR BEHIND AND MAYBE BETTER TO THE NORTH OF THE
AREA.
TODAY/TONIGHT...INITIAL PROBLEM WILL BE COVERAGE AND DURATION OF
SNOWFALL THIS MORNING AS A SHORTWAVE TROUGH AND LIFT FROM THE
UPPER JET MOVE THROUGH. GOING BY THE DNR 00Z SOUNDING...THE BEST
MOISTURE IS ABOVE 700 MB AND REALITY IS SUPPORTING THAT. SO FAR
VISIBILITIES/OBSERVATIONS AND CAMERAS SHOW LITTLE IF ANY
ACCUMULATION...EVEN UNDER THE MOST INTENSE BAND THAT IS ALONG THE
KANSAS AND NEBRASKA BORDER. TEMPERATURE AND DEWPOINT SPREADS ARE
LARGE...ESPECIALLY IN THE NORTH WHERE THE RADAR SAYS THE MOST INTENSE
PRECIPITATION IS. MOST OF THE MODELS SAY THAT MEASURABLE SHOULD BE
OCCURRING AT THIS TIME WITH RUC HAVING THE LEAST MEASURABLE AND
LOOKING THE BEST AT THIS TIME.
RIGHT REAR QUADRANT SHOULD BE EAST OF THE AREA BY 12Z. 7-5H
SHORTWAVE LOOKS TO BE ENTERING THE WESTERN PORTION OF THE FORECAST
AREA AT THIS TIME. SOME PV MOVES ACROSS EARLY WITH THE BRUNT OF IT
NORTH. DOWNGLIDE ALSO MOVES IN RATHER QUICKLY THIS MORNING. WILL
CONTINUE TO WATCH TRENDS FOR CHANGES BUT PLAN ON TAKING THE
MEASURABLE OUT AND HAVE FLURRIES OVER MOST OF THE AREA THIS MORNING
WITH MAYBE A LITTLE LINGERING IN THE FAR EAST INTO THE EARLY
AFTERNOON.
QUESTION THEN BECOMES HOW FAST WE CLEAR OUT AND ITS AFFECT ON HIGH
TEMPERATURES. STRONG JET ON THE BACKSIDE OF THE UPPER TROUGH DOES
NOT GET CLOSE TO THE AREA UNTIL LATE IN THE DAY. BASED ON
SATELLITE...WE SHOULD CLEAR OUT RATHER QUICKLY WITH THE MODELS
LOOKING LIKE THEY ARE HANGING ONTO CLOUDS A LITTLE TOO LONG.
CURRENTLY TEMPERATURES ARE RUNNING A LITTLE WARMER THAN DEPICTED
BUT CLEARING AND TEMPERATURES UPSTREAM SUPPORT MINS GETTING NEAR
WHAT IS CALLED FOR. MODEL GUIDANCE IS SIMILAR IN ITS DEPICTION AND
MADE SLIGHT ADJUSTMENTS BASED ON LATEST TRENDS/GUIDANCE.
ANOTHER CONCERN WILL BE WINDS ON THE BACKSIDE OF THE SYSTEM AS IT
EXITS. LOOKS LIKE WILL HAVE GOOD SUBSIDENCE AND ADIABATIC LAPSE
RATES. SO IT LOOKS LIKE WE WILL SEE A BRIEF PERIOD OF AT LEAST
BREEZY AND GUSTY WINDS THIS AFTERNOON BUT DO NOT SEE ANYTHING
GETTING OUT OF HAND.
JET AXIS MOVES ACROSS THE AREA DURING THE NIGHT...AND AFFECTS THE
NORTHEAST HALF OF THE AREA BY 12Z. THAT AND ANOTHER SHORTWAVE
WILL INCREASE THE CLOUDS AFTER 06Z. NEXT QUESTION WILL BE HOW FAST
THE SURFACE MOVES THROUGH AND HOW FAST DO THE WINDS INCREASE. LIKE
THE SLIGHTLY SLOWER EVOLUTION AND THINK THE GFS IS TOO FAST. AT
THIS TIME...IT LOOKS LIKE TEMPERATURES WILL BOTTOM OUT EARLY...
ESPECIALLY IN THE WEST AND THEN REMAIN STEADY AFTER THAT.
THURSDAY/THURSDAY NIGHT...RIGHT REAR QUADRANT OF THE JET REMAINS
NEAR OR OVER THE AREA THROUGH THE DAY. SOME DIFFERENCE IN THE AMOUNT
OF CLOUD COVER WITH MOST OF THE MODELS SHOWING A MOSTLY SUNNY TO
A PARTLY SUNNY DAY. AS HAS BEEN THE CASE IN THIS FLOW...CLOUDS
MAY BE A LITTLE MORE THAN CURRENTLY THINK. SHOULD START OFF WITH
DOWNSLOPE WINDS BUT THEN THEY SHIFT TO THE SOUTH AS LEE TROUGH
STRENGTHENS. MODELS DO NOT LOOK AS STRONG ON THE WINDS AS YESTERDAY
AS MIXING AND GRADIENT ARE NOT AS STRONG AS PREVIOUSLY DEPICTED.
STRONGEST WINDS WILL BE IN THE EAST. SOME DIFFERENCES IN THE DEPICTED
MAXES. THE 06Z NAM HAS COOLED THINGS OFF A LITTLE FROM 00Z. AT THIS
TIME...WILL TREND TOWARD THE WARMER SIDE OF THE GUIDANCE.
FRIDAY/FRIDAY NIGHT...COMPLEX JET SETUP BEGINS DURING THE DAY.
NORTHERN STREAM REMAINS WELL NORTHWEST OF THE AREA THROUGH THE DAY.
HOWEVER...LEFT FRONT QUADRANT OF A SOUTHERN JET DEVELOPS OR
STRENGTHENS OVER THE AREA THROUGH THE DAY...ESPECIALLY IN THE
AFTERNOON. THERE LOOKS TO BE SOME INCREASING HIGH CLOUDS IN THE
AFTERNOON. CONSIDERING WHAT THE JET IS DOING AND THE STRONG
SOUTHWESTERLY FLOW...LIKE WHAT THE NAM AND ECMWF ARE SHOWING WITH A
STRENGTHENING AND FURTHER WEST LEE TROUGH. THIS MEANS LESS OF A
DOWNSLOPE COMPONENT AND IF MODELS ARE CORRECT MORE OF AN EASTERLY
COMPONENT AS THE DAY WHERES ON. SO WILL TREND TOWARD THE COOLER
SIDE OF GUIDANCE.
AS A SIDE NOTE...DUE TO A MORE EASTERLY WIND AND HIGHER DEWPOINTS...
BELIEVE SHOULD NOT SEE ANY FIRE WEATHER CONCERNS DESPITE THE WARMER
TEMPERATURES.
BULLER
FOR THE PERIOD SATURDAY THROUGH TUESDAY...SHORTWAVE WILL EJECT
ACROSS THE CENTRAL PLAINS SATURDAY FROM BASE OF WEST COAST MEAN
TROUGH. TRACK OF THE UPPER SYSTEM AND MOISTURE PROFILES SUGGEST FROPA
WILL BE DRY. THERE MAY BE A PERIOD OF GUSTY NORTH WINDS BEHIND THE
FRONT SOMETIME ON SATURDAY. COLDER TEMPERATURES WILL FOLLOW ON
SUNDAY...LOW TO MIDDLE 40S FOR HIGHS...WHICH IS AROUND 10 DEGREES
BELOW NORMAL. RETURN FLOW GETS UNDER WAY FOR MONDAY UNDER SHORTWAVE
RIDGING ALOFT WITH TEMPERATURES WARMING TO NEAR NORMAL AND CONTINUED
DRY. REMNANTS OF WEST COAST SYSTEM COMES ACROSS SOUTHERN ROCKIES ON
TUESDAY BRINGING A CHANCE OF MAINLY RAIN...BEST CHANCES WILL BE
SOUTH.
JK
THANKS TO ALL THAT COLLABORATED.
&&
.AVIATION...
1047 PM MST TUE NOV 15 2011
CLOUD COVER WILL INCREASE WITH CEILINGS BECOMING LOWER AS A FAST
MOVING DISTURBANCE MOVES ACROSS THE CENTRAL HIGH PLAINS OVERNIGHT.
CONDITIONS WILL START OUT VFR TONIGHT...BUT WILL LIKELY SEE A DROP
TO MVFR AS CEILINGS LOWER BETWEEN 09 AND 17Z AT KGLD. THERE WILL
ALSO BE THE POSSIBILITY OF LIGHT SNOW MAINLY BETWEEN 09 AND 14 Z
AT KGLD. KMCK WILL SEE A DROP TO MVFR AFTER 11Z THAT CONTINUES
THROUGH 19Z. LIGHT SNOW IS POSSIBLE AT KMCK, BUT IT SEEMS
SLIGHTLY LESS LIKELY THAN KGLD AND LEFT IT OUT. CEILINGS WILL RISE
AGAIN WITH A RETURN TO VFR CONDITIONS AS WINDS TURN NORTHWESTERLY
AND BECOME GUSTY AFTER ABOUT 19Z AS THE SYSTEM BEGINS TO MOVE OUT
OF THE AREA. WINDS WILL DIMINISH AND TURN SOUTHWESTERLY AFTER 00Z
ALONG WITH SKIES CLEARING OUT.
LOCKHART
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
NE...NONE.
CO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
149 PM EST WED NOV 16 2011
.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN OVER THE NORTHERN MID
ATLANTIC REGION THIS AFTERNOON AS A COLD FRONT APPROACHES FROM
THE WEST. THE COLD FRONT PASSES THROUGH TONIGHT...WITH HIGH
PRESSURE RETURNING LATE THURSDAY AND INTO THE WEEKEND. ANOTHER
COLD FRONT APPROACHES SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK STATIONARY FRONT IS SITUATED WSW TO ENE ACRS THE CWA...FROM
ABOUT FARMVILLE TO ASHLAND INTO THE MD EASTERN SHORE. STRONG
TEMPERATURE GRADIENT IN PLACE...AS WELL AS PRECIPITATION CHANCES
OVER THE NEXT FEW HRS. WILL CARRY CAT POPS N/NW ZONES THIS
AFTN...TAPERED TO JUST 20% OVER FAR SE VA/ NE NC. HAVE ADJUSTED
HIGHS A BIT TO SHARPEN THE GRADIENT AS IT WILL TEND TO STAY IN THE
60S OVER THE MD EASTERN SHORE AND TO THE NW OF RICHMOND...WHILE
HIGHS AROUND 80 CAN BE EXPECTED IN A FEW SPOTS IN THE SE.
WHILE A CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST FOR THIS AFTN...THINK
THAT BEST CHANCE FOR SEVERE WX WILL NOT ARRIVE UNTIL THE EVENING
HRS...PRIMARILY ACRS SE VA/NE NC. DOWN THAT WAY IS WHERE BEST COMBINATION
OF MODEST SFC-BASED INSTABILITY (~500 J/KG) WILL CO- EXIST WITH
HIGH SHEAR (0-6 KM BULK SHEAR 60 KT+) . MAIN THREAT WOULD BE DAMAGING
WINDS (>40 KT OF 0-3 KM SHEAR AND DCAPE>1000 J/KG). ALSO...SOME
STORMS MAY EXHIBIT ROTATION AS RUC AND NAM BOTH PROG 0-1 KM HELICITIES>300
M2/S2 AS THE BOUNDARY DROPS THROUGH BETWEEN 02-06Z. MAIN LIMITING
FACTOR MAY BE LACK OF INSTABILITY DUE TO THE TIMEFRAME BEING AFTER
SUNSET ALTHOUGH SFC TEMPS WILL LIKELY BE AROUND 70 F...WITH DEW
PTS IN THE 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BEST PROBABILITY FOR RAIN (CATEGORICAL POPS) COMES TONIGHT DUE TO
A COMBO OF ISENTROPIC LIFT AND STRONG LOW/MID LEVEL CONVERGENCE
ASSOCIATED W/ COLD FRONT. RAIN WILL BE HEAVY AT TIMES AND SOME
AREAS MAY RECEIVE OVER AN INCH TOTAL W/ THIS SYSTEM (ESP N PART OF
FA). NO SIGNIFICANT FLOODING IS ANTICIPATED ATTM DUE TO FLASH
FLOOD GUIDANCE BEING HIGH.
THU...BOTH THE NAM AND THE GFS CONTINUE TO SHOW THE MID/UPPER
LEVEL TROUGH NOT CROSSING THE REGION UNTIL AFTER 18Z. COMBINED
WITH A NNE FLOW IN THE LOW LEVELS AND THE RRQ OF THE UPPER JET...RAIN
WILL BE SLOW TO TAPER OFF AND HAVE BUMPED POPS TO CATEGORICAL FOR
ALL ZONES THROUGH THE MORNING/EARLY AFTN HRS. SHARPLY COLDER
AIRMASS WILL BE IN PLACE AS WELL...MAKING FOR A RAW AND CHILLY DAY
WITH TEMPERATURES MAINLY IN THE 40S (AFTER EARLY AM HIGHS IN THE
50S). DECREASING CLOUDS FROM W TO E LATE (SO THAT COASTAL ZONES
MAY STAY CLOUDY ALL DAY). DIMINISHING WINDS AND CLEARING SKIES
WILL ALLOW FOR MINS INTO THE UPPER 20S WEST OF I-95 THU
NIGHT...30-35 FARTHER EAST.
STRONG HIGH PRESSURE BUILDS OVER THE MID ATLANTIC FRI LEADING TO
DRY WX AND SUNNY SKIES. TEMPS WILL ONLY MAX OUT IN THE U40S-L50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LONG RANGE MODELS ARE IN GOOD AGREEMENT WITH SHOWING A SOUTHWEST
UPPER LEVEL FLOW DEVELOPING SATURDAY AS HIGH PRESSURE BECOMES
ANCHORED OVER THE MID ATLANTIC STATES THROUGH SUNDAY. SOME
CLOUDINESS IS POSSIBLE IN NORTHEAST NC AND EXTREME SOUTHEAST VA ON
SATURDAY AS TROPICAL MOISTURE ROTATES AROUND A MID-LEVEL HIGH OFF
THE SOUTHEAST U.S. COAST AND MOVES NEAR THIS AREA. OTHERWISE...A
DRYING AND WARMING TREND IS ANTICIPATED UNDER THIS FLOW
REGIME...WITH HIGH TEMPS REBOUNDING BACK INTO THE 60S BY SUNDAY.
LOWS SHOULD BE NEAR FREEZING SATURDAY MORNING DUE TO PRIME COOLING
CONDITIONS UNDER MOSTLY CLEAR SKIES WITH VERY LIGHT WINDS...THEN
REBOUND TOWARD THE LOW 50S BY EARLY NEXT WEEK AS CLOUDS INCREASE
AHEAD OF THE NEXT WEATHER DISTURBANCE.
BY LATE SUNDAY...A WEAK COLD FRONT IS EXPECTED TO SAG SOUTHWARD AND
STALL OVER THE MID ATLANTIC REGION THROUGH TUESDAY. 12Z MODEL RUNS
TODAY ARE HINTING AT SLOWING THE SOUTHERN MOVEMENT OF THIS BOUNDARY
UNTIL LATE MONDAY...WHICH WOULD DELAY THE ONSET OF PRECIPITATION
UNTIL THAT TIMEFRAME. HAVE TRENDED THE ONGOING FORECAST TOWARD
SLOWING THE PASSAGE OF THE FRONT UNTIL LATE MONDAY...WITH
PRECIPITATION BEING INTRODUCED LATE SUNDAY/EARLY MONDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
WEAK SFC BOUNDARY LYING ACROSS THE REGION WITH SHORT WAVE ENERGY
MOVG FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST AREA. MOST
OF THE RAIN HAS MOVED ACROSS CENTRAL VA AND THE EASTERN SHORE THIS
MORNING BUT WILL OVERSPREAD SE VA AND NC INTO TONIGHT. RADAR
SHOWING SOME EMBEDDED CONVECTION IN THE RAIN WHICH WILL BRING
BRIEF PERIODS OF HEAVY RAIN AND GUSTY WINDS. CEILINGS HAVE BEEN
MOSTLY MVFR/IFR THIS MORNING AND THIS WILL GENERALLY PERSIST THRU
THE AFTERNOON AND INTO THE EVENING. ANOTHER BOUNDARY (COLD FRONT)
WILL MOVE THRU THE FORECAST AREA BEGINNING EARLY TONIGHT AND
SHOULD BE PUSHED OFF THE COAST BY THU MORNING. MODELS SUGGEST THAT
AREAS OF LOW PRESSURE WILL FORM ALONG THE FRONT AS IT MOVES THRU
THE REGION AND THIS WILL HELP TO ENHANCE CHANCE OF HEAVY RAIN OR
ISOLD TSTMS FOR THE OVERNIGHT PERIOD. EXPECT MOSTLY MVFR CONDITIONS
WITH TEMPO IFR THRU THE OVERNIGHT.
HIGH PRESSURE WILL BUILD IN LATE THU AND WILL SETTLE OVER THE
AREA THU NIGHT INTO FRI. VFR AND DRY CONDITIONS WILL PREVAIL THRU
THE WEEKEND.
&&
.MARINE...
HAVE EXTENDED THE SCA HEADLINE FOR ALL THE WTRS THRU LATE THU
NGT...AS NNW WNDS (CAA) WILL CONTINUE AT 15 TO 25 KT AND
WAVES/SEAS WILL STAY UP. SE OR S WNDS 10 KT OR LESS ERLY THIS
MORNG...WILL BECOME SW AND INCRS TO 15 TO 20 KT THIS AFTN IN
ADVANCE OF COLD FRNT. CUD BE GUSTS TO 25 KT. WNDS WILL SHIFT TO
THE NW OR N THIS EVENG INTO ERLY THU MORNG BEHIND THE FRNT. THIS
CAA SURGE WILL THEN CONTINUE FOR THE REMAINDER OF THU AND THU NGT.
MORE BENIGN MARINE CONDITIONS THEN EXPECTED FRI INTO SUN...AS HI
PRES BLDS OVR THE WTRS FM THE W.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR NOV 16TH (WED):
RIC...85 IN 1955
ORF...83 IN 1955
SBY...78 IN 1928
ECG...85 IN 1993
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ630>634-650-
652-654-656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...LKB
SHORT TERM...LKB/MAS
LONG TERM...BMD
AVIATION...JEF
MARINE...TMG
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1145 AM EST WED NOV 16 2011
.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN OVER THE NORTHERN MID
ATLANTIC REGION THIS AFTERNOON AS A COLD FRONT APPROACHES FROM
THE WEST. THE COLD FRONT PASSES THROUGH TONIGHT...WITH HIGH
PRESSURE RETURNING LATE THURSDAY AND INTO THE WEEKEND. ANOTHER
COLD FRONT APPROACHES SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /UNTIL MIDNIGHT/...
WEAK STATIONARY FRONT IS SITUATED WSW TO ENE ACRS THE CWA...FROM
ABOUT FARMVILLE TO ASHLAND INTO THE MD EASTERN SHORE. STRONG
TEMPERATURE GRADIENT IN PLACE...AS WELL AS PRECIPITATION CHANCES
OVER THE NEXT FEW HRS. WILL CARRY CAT POPS N/NW ZONES THIS
AFTN...TAPERED TO JUST 20% OVER FAR SE VA/ NE NC. HAVE ADJUSTED
HIGHS A BIT TO SHARPEN THE GRADIENT AS IT WILL TEND TO STAY IN THE
60S OVER THE MD EASTERN SHORE AND TO THE NW OF RICHMOND...WHILE
HIGHS AROUND 80 CAN BE EXPECTED IN A FEW SPOTS IN THE SE.
WHILE A CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST FOR THIS AFTN...THINK
THAT BEST CHANCE FOR SEVERE WX WILL NOT ARRIVE UNTIL THE EVENING
HRS...PRIMARILY ACRS SE VA/NE NC. DOWN THAT WAY IS WHERE BEST COMBINATION
OF MODEST SFC-BASED INSTABILITY (~500 J/KG) WILL CO- EXIST WITH
HIGH SHEAR (0-6 KM BULK SHEAR 60 KT+) . MAIN THREAT WOULD BE DAMAGING
WINDS (>40 KT OF 0-3 KM SHEAR AND DCAPE>1000 J/KG). ALSO...SOME
STORMS MAY EXHIBIT ROTATION AS RUC AND NAM BOTH PROG 0-1 KM HELICITIES>300
M2/S2 AS THE BOUNDARY DROPS THROUGH BETWEEN 02-06Z. MAIN LIMITING
FACTOR MAY BE LACK OF INSTABILITY DUE TO THE TIMEFRAME BEING AFTER
SUNSET ALTHOUGH SFC TEMPS WILL LIKELY BE AROUND 70 F...WITH DEW
PTS IN THE 60S.
&&
.SHORT TERM /MIDNIGHT THROUGH FRIDAY/...
BEST PROBABILITY FOR RAIN (CATEGORICAL POPS) COMES TONIGHT DUE TO
A COMBO OF ISENTROPIC LIFT AND STRONG LOW/MID LEVEL CONVERGENCE
ASSOCIATED W/ COLD FRONT. RAIN WILL BE HEAVY AT TIMES AND SOME
AREAS MAY RECEIVE OVER AN INCH TOTAL W/ THIS SYSTEM (ESP N PART OF
FA). NO SIGNIFICANT FLOODING IS ANTICIPATED ATTM DUE TO FLASH
FLOOD GUIDANCE BEING HIGH.
THU...BOTH THE NAM AND THE GFS CONTINUE TO SHOW THE MID/UPPER
LEVEL TROUGH NOT CROSSING THE REGION UNTIL AFTER 18Z. COMBINED
WITH A NNE FLOW IN THE LOW LEVELS AND THE RRQ OF THE UPPER JET...RAIN
WILL BE SLOW TO TAPER OFF AND HAVE BUMPED POPS TO CATEGORICAL FOR
ALL ZONES THROUGH THE MORNING/EARLY AFTN HRS. SHARPLY COLDER
AIRMASS WILL BE IN PLACE AS WELL...MAKING FOR A RAW AND CHILLY DAY
WITH TEMPERATURES MAINLY IN THE 40S (AFTER EARLY AM HIGHS IN THE
50S). DECREASING CLOUDS FROM W TO E LATE (SO THAT COASTAL ZONES
MAY STAY CLOUDY ALL DAY). DIMINISHING WINDS AND CLEARING SKIES
WILL ALLOW FOR MINS INTO THE UPPER 20S WEST OF I-95 THU
NIGHT...30-35 FARTHER EAST.
STRONG HIGH PRESSURE BUILDS OVER THE MID ATLANTIC FRI LEADING TO
DRY WX AND SUNNY SKIES. TEMPS WILL ONLY MAX OUT IN THE U40S-L50S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LONG RANGE MODELS ARE IN GOOD AGREEMENT WITH SHOWING A SOUTHWEST
UPPER LEVEL FLOW DEVELOPING SATURDAY AS HIGH PRESSURE BECOMES
ANCHORED OVER THE MID ATLANTIC STATES THROUGH SUNDAY. SOME
CLOUDINESS IS POSSIBLE IN NORTHEAST NC AND EXTREME SOUTHEAST VA ON
SATURDAY AS TROPICAL MOISTURE ROTATES AROUND A MID-LEVEL HIGH OFF
THE SOUTHEAST U.S. COAST AND MOVES NEAR THIS AREA. OTHERWISE...A
DRYING AND WARMING TREND IS ANTICIPATED UNDER THIS FLOW
REGIME...WITH HIGH TEMPS REBOUNDING BACK INTO THE 60S BY SUNDAY.
LOWS SHOULD BE NEAR FREEZING SATURDAY MORNING DUE TO PRIME COOLING
CONDITIONS UNDER MOSTLY CLEAR SKIES WITH VERY LIGHT WINDS...THEN
REBOUND TOWARD THE LOW 50S BY EARLY NEXT WEEK AS CLOUDS INCREASE
AHEAD OF THE NEXT WEATHER DISTURBANCE.
BY LATE SUNDAY...A WEAK COLD FRONT IS EXPECTED TO SAG SOUTHWARD AND
STALL OVER THE MID ATLANTIC REGION THROUGH TUESDAY. 12Z MODEL RUNS
TODAY ARE HINTING AT SLOWING THE SOUTHERN MOVEMENT OF THIS BOUNDARY
UNTIL LATE MONDAY...WHICH WOULD DELAY THE ONSET OF PRECIPITATION
UNTIL THAT TIMEFRAME. HAVE TRENDED THE ONGOING FORECAST TOWARD
SLOWING THE PASSAGE OF THE FRONT UNTIL LATE MONDAY...WITH
PRECIPITATION BEING INTRODUCED LATE SUNDAY/EARLY MONDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
COLD FRNT WILL APPROACH THE AREA THRU THIS MORNG...THEN DROP ACRS
THE REGION THIS AFTN THRU TNGT. CIGS/VSBYS WILL QUICKLY LWR TO
MVFR THEN IFR (LIFR?) DURING THIS MORNG WITH -DZ OR SCTD -SHRAS
MOVNG INTO NRN AND WRN AREAS. CIGS/VSBYS WILL LIKELY LIFT TO MVFR
AND VFR CONDITIONS LATER THIS MORNG AND AFTN...AS SW WNDS INCRS IN
ADVANCE OF FRNT...WITH ISLTD TO SCTD SHRAS AHEAD OF AND ALNG THE
FRNTL BNDRY INTO THIS EVENG. DURING THIS EVENG INTO THU
MORNG...IFR (LIFR?) CONDITIONS WITH -RA EXPECTED BEHIND THE FRNT.
VFR AND DRY CONDITIONS WILL RETURN THU AFTN THRU SUN.
&&
.MARINE...
HAVE EXTENDED THE SCA HEADLINE FOR ALL THE WTRS THRU LATE THU
NGT...AS NNW WNDS (CAA) WILL CONTINUE AT 15 TO 25 KT AND
WAVES/SEAS WILL STAY UP. SE OR S WNDS 10 KT OR LESS ERLY THIS
MORNG...WILL BECOME SW AND INCRS TO 15 TO 20 KT THIS AFTN IN
ADVANCE OF COLD FRNT. CUD BE GUSTS TO 25 KT. WNDS WILL SHIFT TO
THE NW OR N THIS EVENG INTO ERLY THU MORNG BEHIND THE FRNT. THIS
CAA SURGE WILL THEN CONTINUE FOR THE REMAINDER OF THU AND THU NGT.
MORE BENIGN MARINE CONDITIONS THEN EXPECTED FRI INTO SUN...AS HI
PRES BLDS OVR THE WTRS FM THE W.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR NOV 16TH (WED):
RIC...85 IN 1955
ORF...83 IN 1955
SBY...78 IN 1928
ECG...85 IN 1993
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ630>634-650-
652-654-656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...LKB
SHORT TERM...LKB/MAS
LONG TERM...BMD
AVIATION...TMG
MARINE...TMG
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
646 AM EST WED NOV 16 2011
.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN OVER THE MID ATLANTIC REGION
EARLY TODAY AS A COLD FRONT APPROACHES FROM THE WEST. THE COLD
FRONT PASSES THROUGH TONIGHT...WITH HIGH PRESSURE RETURNING LATE
THURSDAY AND INTO THE WEEKEND. ANOTHER COLD FRONT APPROACHES
SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK STATIONARY FRONT OVER THE MID ATLANTIC IS EXPECTED TO SLOWLY
NUDGE NORTH THIS MORNING...ALLOWING FOR SW WARM AND MOIST FLOW TO
CONTINUE OVER THE LOCAL AREA. CYCLONIC FLOW ALOFT AND DECENT MID-LEVEL
MOISTURE ADVECTION WILL LEAD TO MOSTLY CLOUDY SKIES...WITH SOME
BREAKS POSSIBLE ESP TO THE S. PRECIP CURRENTLY OVER WESTERN
VIRGINIA IS EXPECTED TO CLIP NORTHERN PORTIONS OF THE FA LATER
THIS MORNING. LOWER CHANCES FOR RAIN FURTHER S WHERE THE BEST FORCING
AND DEEP MOISTURE WILL HOLD OFF UNTIL LATER TODAY AND TONIGHT. A
COLD FRONT APPROACHING FROM THE OHIO VALLEY AND A DEVELOPING SFC
WAVE (IN RESPONSE TO A POTENT S/W OVER THE TN VALLEY EMBEDDED
WITHIN THE SW UPPER FLOW) WILL ALSO INCREASE THE RAIN POTENTIAL
STARTING LATE THIS AFTERNOON.
CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST...W/ STRONG LOW-TOPPED
CONVECTION (LOW CAPE AND HIGH SHEAR) POSSIBLE...ESP FOR NE NORTH
CAROLINA AND EXTREME SE VIRGINIA (SPC HAS A SLIGHT RISK) WHERE
INSTABILITY WILL BE GREATEST. MAIN THREAT WOULD BE DAMAGING WINDS
(>40 KT OF 0-3 KM SHEAR AND DCAPE>1000 J/KG). ALSO...SOME STORMS
MAY EXHIBIT ROTATION AS RUC AND NAM BOTH PROG 0-1 KM
HELICITIES>300 M2/S2. MAIN LIMITING FACTOR MAY BE LACK OF
INSTABILITY DUE TO MOSTLY CLOUDY SKIES. EXPECT ABOVE NORMAL HIGHS
AGAIN TODAY SINCE COLD FROPA HOLDS OFF UNTIL EVENING...HIGHS IN THE
L-M70S OVER THE NW AND M-U70S OVER THE SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BEST PROBABILITY FOR RAIN (CATEGORICAL POPS) COMES TONIGHT DUE TO A
COMBO OF ISENTROPIC LIFT AND STRONG LOW/MID LEVEL CONVERGENCE
ASSOCIATED W/ COLD FRONT. RAIN WILL BE HEAVY AT TIMES AND SOME
AREAS MAY RECEIVE OVER AN INCH TOTAL W/ THIS SYSTEM (ESP N PART OF
FA). NO SIGNIFICANT FLOODING IS ANTICIPATED ATTM DUE TO FLASH
FLOOD GUIDANCE BEING HIGH. THE RAIN TAPERS OFF FROM W TO E THUR
MIDDAY/AFTERNOON. DECREASING CLOUDS FOR THE REST OF THE DAY AND
NIGHT. COOL N FLOW AT THE SFC WILL ONLY YIELD HIGHS IN THE L-M50S
THUR.
STRONG HIGH PRESSURE BUILDS OVER THE MID ATLANTIC FRI LEADING TO
DRY WX AND SUNNY SKIES. TEMPS WILL ONLY MAX OUT IN THE U40S-L50S AFTER
A CHILLY START IN THE U20S-M30S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LONG RANGE MODELS ARE IN GOOD AGREEMENT WITH SHOWING A SOUTHWEST
UPPER LEVEL FLOW DEVELOPING SATURDAY AS HIGH PRESSURE BECOMES
ANCHORED OVER THE MID ATLANTIC STATES THROUGH SUNDAY. SOME
CLOUDINESS IS POSSIBLE IN NORTHEAST NC AND EXTREME SOUTHEAST VA ON
SATURDAY AS TROPICAL MOISTURE ROTATES AROUND A MID-LEVEL HIGH OFF
THE SOUTHEAST U.S. COAST AND MOVES NEAR THIS AREA. OTHERWISE...A
DRYING AND WARMING TREND IS ANTICIPATED UNDER THIS FLOW
REGIME...WITH HIGH TEMPS REBOUNDING BACK INTO THE 60S BY SUNDAY.
LOWS SHOULD BE NEAR FREEZING SATURDAY MORNING DUE TO PRIME COOLING
CONDITIONS UNDER MOSTLY CLEAR SKIES WITH VERY LIGHT WINDS...THEN
REBOUND TOWARD THE LOW 50S BY EARLY NEXT WEEK AS CLOUDS INCREASE
AHEAD OF THE NEXT WEATHER DISTURBANCE.
BY LATE SUNDAY...A WEAK COLD FRONT IS EXPECTED TO SAG SOUTHWARD AND
STALL OVER THE MID ATLANTIC REGION THROUGH TUESDAY. 12Z MODEL RUNS
TODAY ARE HINTING AT SLOWING THE SOUTHERN MOVEMENT OF THIS BOUNDARY
UNTIL LATE MONDAY...WHICH WOULD DELAY THE ONSET OF PRECIPITATION
UNTIL THAT TIMEFRAME. HAVE TRENDED THE ONGOING FORECAST TOWARD
SLOWING THE PASSAGE OF THE FRONT UNTIL LATE MONDAY...WITH
PRECIPITATION BEING INTRODUCED LATE SUNDAY/EARLY MONDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
COLD FRNT WILL APPROACH THE AREA THRU THIS MORNG...THEN DROP ACRS
THE REGION THIS AFTN THRU TNGT. CIGS/VSBYS WILL QUICKLY LWR TO
MVFR THEN IFR (LIFR?) DURING THIS MORNG WITH -DZ OR SCTD -SHRAS
MOVNG INTO NRN AND WRN AREAS. CIGS/VSBYS WILL LIKELY LIFT TO MVFR
AND VFR CONDITIONS LATER THIS MORNG AND AFTN...AS SW WNDS INCRS IN
ADVANCE OF FRNT...WITH ISLTD TO SCTD SHRAS AHEAD OF AND ALNG THE
FRNTL BNDRY INTO THIS EVENG. DURING THIS EVENG INTO THU
MORNG...IFR (LIFR?) CONDITIONS WITH -RA EXPECTED BEHIND THE FRNT.
VFR AND DRY CONDITIONS WILL RETURN THU AFTN THRU SUN.
&&
.MARINE...
HAVE EXTENDED THE SCA HEADLINE FOR ALL THE WTRS THRU LATE THU
NGT...AS NNW WNDS (CAA) WILL CONTINUE AT 15 TO 25 KT AND
WAVES/SEAS WILL STAY UP. SE OR S WNDS 10 KT OR LESS ERLY THIS
MORNG...WILL BECOME SW AND INCRS TO 15 TO 20 KT THIS AFTN IN
ADVANCE OF COLD FRNT. CUD BE GUSTS TO 25 KT. WNDS WILL SHIFT TO
THE NW OR N THIS EVENG INTO ERLY THU MORNG BEHIND THE FRNT. THIS
CAA SURGE WILL THEN CONTINUE FOR THE REMAINDER OF THU AND THU NGT.
MORE BENIGN MARINE CONDITIONS THEN EXPECTED FRI INTO SUN...AS HI
PRES BLDS OVR THE WTRS FM THE W.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR NOV 16TH (WED):
RIC...85 IN 1955
ORF...83 IN 1955
SBY...78 IN 1928
ECG...85 IN 1993
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EST FRIDAY FOR
ANZ630>634-650-652-654-656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...TMG
MARINE...TMG
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
632 AM EST WED NOV 16 2011
.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN OVER THE MID ATLANTIC REGION
EARLY TODAY AS A COLD FRONT APPROACHES FROM THE WEST. THE COLD
FRONT PASSES THROUGH TONIGHT...WITH HIGH PRESSURE RETURNING LATE
THURSDAY AND INTO THE WEEKEND. ANOTHER COLD FRONT APPROACHES
SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK STATIONARY FRONT OVER THE MID ATLANTIC IS EXPECTED TO SLOWLY
NUDGE NORTH THIS MORNING...ALLOWING FOR SW WARM AND MOIST FLOW TO
CONTINUE OVER THE LOCAL AREA. CYCLONIC FLOW ALOFT AND DECENT MID-LEVEL
MOISTURE ADVECTION WILL LEAD TO MOSTLY CLOUDY SKIES...WITH SOME
BREAKS POSSIBLE ESP TO THE S. PRECIP CURRENTLY OVER WESTERN
VIRGINIA IS EXPECTED TO CLIP NORTHERN PORTIONS OF THE FA LATER
THIS MORNING. LOWER CHANCES FOR RAIN FURTHER S WHERE THE BEST FORCING
AND DEEP MOISTURE WILL HOLD OFF UNTIL LATER TODAY AND TONIGHT. A
COLD FRONT APPROACHING FROM THE OHIO VALLEY AND A DEVELOPING SFC
WAVE (IN RESPONSE TO A POTENT S/W OVER THE TN VALLEY EMBEDDED
WITHIN THE SW UPPER FLOW) WILL ALSO INCREASE THE RAIN POTENTIAL
STARTING LATE THIS AFTERNOON.
CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST...W/ STRONG LOW-TOPPED
CONVECTION (LOW CAPE AND HIGH SHEAR) POSSIBLE...ESP FOR NE NORTH
CAROLINA AND EXTREME SE VIRGINIA (SPC HAS A SLIGHT RISK) WHERE
INSTABILITY WILL BE GREATEST. MAIN THREAT WOULD BE DAMAGING WINDS
(>40 KT OF 0-3 KM SHEAR AND DCAPE>1000 J/KG). ALSO...SOME STORMS
MAY EXHIBIT ROTATION AS RUC AND NAM BOTH PROG 0-1 KM
HELICITIES>300 M2/S2. EXPECT ABOVE NORMAL HIGHS AGAIN TODAY DUE TO
THE COLD FROPA BEING DELAYED UNTIL TONIGHT...HIGHS IN THE L-M70S
OVER THE NW AND M-U70S OVER THE SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BEST PROBABILITY FOR RAIN (CATEGORICAL POPS) COMES TONIGHT DUE TO A
COMBO OF ISENTROPIC LIFT AND STRONG LOW/MID LEVEL CONVERGENCE
ASSOCIATED W/ COLD FRONT. RAIN WILL BE HEAVY AT TIMES AND SOME
AREAS MAY RECEIVE OVER AN INCH TOTAL W/ THIS SYSTEM (ESP N PART OF
FA). NO SIGNIFICANT FLOODING IS ANTICIPATED ATTM DUE TO FLASH
FLOOD GUIDANCE BEING HIGH. THE RAIN TAPERS OFF FROM W TO E THUR
MIDDAY/AFTERNOON. DECREASING CLOUDS FOR THE REST OF THE DAY AND
NIGHT. COOL N FLOW AT THE SFC WILL ONLY YIELD HIGHS IN THE L-M50S
THUR.
STRONG HIGH PRESSURE BUILDS OVER THE MID ATLANTIC FRI LEADING TO
DRY WX AND SUNNY SKIES. TEMPS WILL ONLY MAX OUT IN THE U40S-L50S AFTER
A CHILLY START IN THE U20S-M30S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LONG RANGE MODELS ARE IN GOOD AGREEMENT WITH SHOWING A SOUTHWEST
UPPER LEVEL FLOW DEVELOPING SATURDAY AS HIGH PRESSURE BECOMES
ANCHORED OVER THE MID ATLANTIC STATES THROUGH SUNDAY. SOME
CLOUDINESS IS POSSIBLE IN NORTHEAST NC AND EXTREME SOUTHEAST VA ON
SATURDAY AS TROPICAL MOISTURE ROTATES AROUND A MID-LEVEL HIGH OFF
THE SOUTHEAST U.S. COAST AND MOVES NEAR THIS AREA. OTHERWISE...A
DRYING AND WARMING TREND IS ANTICIPATED UNDER THIS FLOW
REGIME...WITH HIGH TEMPS REBOUNDING BACK INTO THE 60S BY SUNDAY.
LOWS SHOULD BE NEAR FREEZING SATURDAY MORNING DUE TO PRIME COOLING
CONDITIONS UNDER MOSTLY CLEAR SKIES WITH VERY LIGHT WINDS...THEN
REBOUND TOWARD THE LOW 50S BY EARLY NEXT WEEK AS CLOUDS INCREASE
AHEAD OF THE NEXT WEATHER DISTURBANCE.
BY LATE SUNDAY...A WEAK COLD FRONT IS EXPECTED TO SAG SOUTHWARD AND
STALL OVER THE MID ATLANTIC REGION THROUGH TUESDAY. 12Z MODEL RUNS
TODAY ARE HINTING AT SLOWING THE SOUTHERN MOVEMENT OF THIS BOUNDARY
UNTIL LATE MONDAY...WHICH WOULD DELAY THE ONSET OF PRECIPITATION
UNTIL THAT TIMEFRAME. HAVE TRENDED THE ONGOING FORECAST TOWARD
SLOWING THE PASSAGE OF THE FRONT UNTIL LATE MONDAY...WITH
PRECIPITATION BEING INTRODUCED LATE SUNDAY/EARLY MONDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
COLD FRNT WILL APPROACH THE AREA THRU THIS MORNG...THEN DROP ACRS
THE REGION THIS AFTN THRU TNGT. CIGS/VSBYS WILL QUICKLY LWR TO
MVFR THEN IFR (LIFR?) DURING THIS MORNG WITH -DZ OR SCTD -SHRAS
MOVNG INTO NRN AND WRN AREAS. CIGS/VSBYS WILL LIKELY LIFT TO MVFR
AND VFR CONDITIONS LATER THIS MORNG AND AFTN...AS SW WNDS INCRS IN
ADVANCE OF FRNT...WITH ISLTD TO SCTD SHRAS AHEAD OF AND ALNG THE
FRNTL BNDRY INTO THIS EVENG. DURING THIS EVENG INTO THU
MORNG...IFR (LIFR?) CONDITIONS WITH -RA EXPECTED BEHIND THE FRNT.
VFR AND DRY CONDITIONS WILL RETURN THU AFTN THRU SUN.
&&
.MARINE...
HAVE EXTENDED THE SCA HEADLINE FOR ALL THE WTRS THRU LATE THU
NGT...AS NNW WNDS (CAA) WILL CONTINUE AT 15 TO 25 KT AND
WAVES/SEAS WILL STAY UP. SE OR S WNDS 10 KT OR LESS ERLY THIS
MORNG...WILL BECOME SW AND INCRS TO 15 TO 20 KT THIS AFTN IN
ADVANCE OF COLD FRNT. CUD BE GUSTS TO 25 KT. WNDS WILL SHIFT TO
THE NW OR N THIS EVENG INTO ERLY THU MORNG BEHIND THE FRNT. THIS
CAA SURGE WILL THEN CONTINUE FOR THE REMAINDER OF THU AND THU NGT.
MORE BENIGN MARINE CONDITIONS THEN EXPECTED FRI INTO SUN...AS HI
PRES BLDS OVR THE WTRS FM THE W.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR NOV 16TH (WED):
RIC...85 IN 1955
ORF...83 IN 1955
SBY...78 IN 1928
ECG...85 IN 1993
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EST FRIDAY FOR
ANZ630>634-650-652-654-656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...TMG
MARINE...TMG
CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
427 AM EST WED NOV 16 2011
.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN OVER THE MID ATLANTIC REGION
EARLY TODAY AS A COLD FRONT APPROACHES FROM THE WEST. THE COLD
FRONT PASSES THROUGH TONIGHT...WITH HIGH PRESSURE RETURNING LATE
THURSDAY AND INTO THE WEEKEND. ANOTHER COLD FRONT APPROACHES
SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK STATIONARY FRONT OVER THE MID ATLANTIC IS EXPECTED TO SLOWLY
NUDGE NORTH THIS MORNING...ALLOWING FOR SW WARM AND MOIST FLOW TO
CONTINUE OVER THE LOCAL AREA. CYCLONIC FLOW ALOFT AND DECENT MID-LEVEL
MOISTURE ADVECTION WILL LEAD TO MOSTLY CLOUDY SKIES...WITH SOME
BREAKS POSSIBLE ESP TO THE S. PRECIP CURRENTLY OVER WESTERN
VIRGINIA IS EXPECTED TO CLIP NORTHERN PORTIONS OF THE FA LATER
THIS MORNING. LOWER CHANCES FOR RAIN FURTHER S WHERE THE BEST FORCING
AND DEEP MOISTURE WILL HOLD OFF UNTIL LATER TODAY AND TONIGHT. A
COLD FRONT APPROACHING FROM THE OHIO VALLEY AND A DEVELOPING SFC
WAVE (IN RESPONSE TO A POTENT S/W OVER THE TN VALLEY EMBEDDED
WITHIN THE SW UPPER FLOW) WILL ALSO INCREASE THE RAIN POTENTIAL
STARTING LATE THIS AFTERNOON.
CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST...W/ STRONG LOW-TOPPED
CONVECTION (LOW CAPE AND HIGH SHEAR) POSSIBLE...ESP FOR NE NORTH
CAROLINA AND EXTREME SE VIRGINIA (SPC HAS A SLIGHT RISK) WHERE
INSTABILITY WILL BE GREATEST. MAIN THREAT WOULD BE DAMAGING WINDS
(40 KT OF 0-3 KM SHEAR AND DCAPE>1000 J/KG). ALSO...SOME STORMS
MAY EXHIBIT ROTATION AS RUC AND NAM BOTH PROGGING 0-1 KM
HELICITIES GREATER THAN 200 M2/S2. EXPECTING ABOVE NORMAL HIGHS
AGAIN TODAY DUE TO THE COLD FROPA BEING DELAYED UNTIL
TONIGHT...HIGHS IN THE L-M70S OVER THE NW AND M-U70S OVER THE SE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BEST PROBABILITY FOR RAIN (CATEGORICAL POPS) COMES TONIGHT DUE TO A
COMBO OF ISENTROPIC LIFT AND STRONG LOW/MID LEVEL CONVERGENCE
ASSOCIATED W/ COLD FRONT. RAIN WILL BE HEAVY AT TIMES AND SOME
AREAS MAY RECEIVE OVER AN INCH TOTAL W/ THIS SYSTEM (ESP NORTHERN
AREAS). NO SIGNIFICANT FLOODING IS ANTICIPATED ATTM DUE TO FLASH
FLOOD GUIDANCE BEING VERY HIGH. THE RAIN TAPERS OFF FROM W TO E
THUR MIDDAY/AFTERNOON. DECREASING CLOUDS FOR THE REST OF THE DAY
AND NIGHT. COOL N FLOW AT THE SFC WILL ONLY YIELD HIGHS IN THE
L-M50S THUR.
STRONG HIGH PRESSURE BUILDS OVER THE MID ATLANTIC FRI LEADING TO
DRY WX AND SUNNY SKIES. TEMPS WILL ONLY MAX OUT IN THE U40S-L50S AFTER
A CHILLY START IN THE U20S-M30S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LONG RANGE MODELS ARE IN GOOD AGREEMENT WITH SHOWING A SOUTHWEST
UPPER LEVEL FLOW DEVELOPING SATURDAY AS HIGH PRESSURE BECOMES
ANCHORED OVER THE MID ATLANTIC STATES THROUGH SUNDAY. SOME
CLOUDINESS IS POSSIBLE IN NORTHEAST NC AND EXTREME SOUTHEAST VA ON
SATURDAY AS TROPICAL MOISTURE ROTATES AROUND A MID-LEVEL HIGH OFF
THE SOUTHEAST U.S. COAST AND MOVES NEAR THIS AREA. OTHERWISE...A
DRYING AND WARMING TREND IS ANTICIPATED UNDER THIS FLOW
REGIME...WITH HIGH TEMPS REBOUNDING BACK INTO THE 60S BY SUNDAY.
LOWS SHOULD BE NEAR FREEZING SATURDAY MORNING DUE TO PRIME COOLING
CONDITIONS UNDER MOSTLY CLEAR SKIES WITH VERY LIGHT WINDS...THEN
REBOUND TOWARD THE LOW 50S BY EARLY NEXT WEEK AS CLOUDS INCREASE
AHEAD OF THE NEXT WEATHER DISTURBANCE.
BY LATE SUNDAY...A WEAK COLD FRONT IS EXPECTED TO SAG SOUTHWARD AND
STALL OVER THE MID ATLANTIC REGION THROUGH TUESDAY. 12Z MODEL RUNS
TODAY ARE HINTING AT SLOWING THE SOUTHERN MOVEMENT OF THIS BOUNDARY
UNTIL LATE MONDAY...WHICH WOULD DELAY THE ONSET OF PRECIPITATION
UNTIL THAT TIMEFRAME. HAVE TRENDED THE ONGOING FORECAST TOWARD
SLOWING THE PASSAGE OF THE FRONT UNTIL LATE MONDAY...WITH
PRECIPITATION BEING INTRODUCED LATE SUNDAY/EARLY MONDAY.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
COLD FRNT WILL APPROACH THE AREA THRU THIS MORNG...THEN DROP ACRS
THE REGION THIS AFTN THRU TNGT. CIGS/VSBYS WILL QUICKLY LWR TO
MVFR THEN IFR (LIFR?) DURING THIS MORNG WITH -DZ OR SCTD -SHRAS
MOVNG INTO NRN AND WRN AREAS. CIGS/VSBYS WILL LIKELY LIFT TO MVFR
AND VFR CONDITIONS LATER THIS MORNG AND AFTN...AS SW WNDS INCRS IN
ADVANCE OF FRNT...WITH ISLTD TO SCTD SHRAS AHEAD OF AND ALNG THE
FRNTL BNDRY INTO THIS EVENG. DURING THIS EVENG INTO THU
MORNG...IFR (LIFR?) CONDITIONS WITH -RA EXPECTED BEHIND THE FRNT.
VFR AND DRY CONDITIONS WILL RETURN THU AFTN THRU SUN.
&&
.MARINE...
HAVE EXTENDED THE SCA HEADLINE FOR ALL THE WTRS THRU LATE THU
NGT...AS NNW WNDS (CAA) WILL CONTINUE AT 15 TO 25 KT AND
WAVES/SEAS WILL STAY UP. SE OR S WNDS 10 KT OR LESS ERLY THIS
MORNG...WILL BECOME SW AND INCRS TO 15 TO 20 KT THIS AFTN IN
ADVANCE OF COLD FRNT. CUD BE GUSTS TO 25 KT. WNDS WILL SHIFT TO
THE NW OR N THIS EVENG INTO ERLY THU MORNG BEHIND THE FRNT. THIS
CAA SURGE WILL THEN CONTINUE FOR THE REMAINDER OF THU AND THU NGT.
MORE BENIGN MARINE CONDITIONS THEN EXPECTED FRI INTO SUN...AS HI
PRES BLDS OVR THE WTRS FM THE W.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR NOV 16TH (WED):
RIC...85 IN 1955
ORF...83 IN 1955
SBY...78 IN 1928
ECG...85 IN 1993
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EST FRIDAY FOR
ANZ630>634-650-652-654-656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...TMG
MARINE...TMG
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
400 AM EST WED NOV 16 2011
.SYNOPSIS...
A WEAK STATIONARY FRONT WILL REMAIN OVER THE MID ATLANTIC REGION
EARLY TODAY AS A COLD FRONT APPROACHES FROM THE WEST. THE COLD
FRONT PASSES THROUGH TONIGHT...WITH HIGH PRESSURE RETURNING LATE
THURSDAY AND INTO THE WEEKEND. ANOTHER COLD FRONT APPROACHES
SUNDAY NIGHT INTO MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK STATIONARY FRONT OVER THE MID ATLANTIC IS EXPECTED TO SLOWLY
NUDGE NORTH THIS MORNING...ALLOWING FOR SW WARM AND MOIST FLOW TO
CONTINUE OVER THE LOCAL AREA. CYCLONIC FLOW ALOFT AND DECENT MID-LEVEL
MOISTURE ADVECTION WILL LEAD TO MOSTLY CLOUDY SKIES...WITH SOME
BREAKS POSSIBLE ESP TO THE S. PRECIP CURRENTLY OVER WESTERN
VIRGINIA IS EXPECTED TO CLIP NORTHERN PORTIONS OF THE FA LATER
THIS MORNING. LOWER CHANCES FOR RAIN FURTHER S WHERE THE BEST FORCING
AND DEEP MOISTURE WILL HOLD OFF UNTIL LATER TODAY AND TONIGHT. A
COLD FRONT APPROACHING FROM THE OHIO VALLEY AND A DEVELOPING SFC
WAVE (IN RESPONSE TO A POTENT S/W OVER THE TN VALLEY EMBEDDED
WITHIN THE SW UPPER FLOW) WILL ALSO INCREASE THE RAIN POTENTIAL
STARTING LATE THIS AFTERNOON.
CHANCE OF THUNDERSTORMS REMAINS IN THE FORECAST...W/ STRONG LOW-TOPPED
CONVECTION (LOW CAPE AND HIGH SHEAR) POSSIBLE...ESP FOR NE NORTH
CAROLINA AND EXTREME SE VIRGINIA (SPC HAS A SLIGHT RISK) WHERE
INSTABILITY WILL BE GREATEST. MAIN THREAT WOULD BE DAMAGING WINDS
(40 KT OF 0-3 KM SHEAR AND DCAPE>1000 J/KG). ALSO...SOME STORMS
MAY EXHIBIT ROTATION AS RUC AND NAM BOTH PROGGING 0-1 KM
HELICITIES GREATER THAN 200 M2/S2. EXPECTING ABOVE NORMAL HIGHS
AGAIN TODAY DUE TO THE COLD FROPA BEING DELAYED UNTIL
TONIGHT...HIGHS IN THE L-M70S OVER THE NW AND M-U70S OVER THE SE.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
BEST PROBABILITY FOR RAIN (CATEGORICAL POPS) COMES TONIGHT DUE TO A
COMBO OF ISENTROPIC LIFT AND STRONG LOW/MID LEVEL CONVERGENCE
ASSOCIATED W/ COLD FRONT. RAIN WILL BE HEAVY AT TIMES AND SOME
AREAS MAY RECEIVE OVER AN INCH TOTAL W/ THIS SYSTEM (ESP NORTHERN
AREAS). NO SIGNIFICANT FLOODING IS ANTICIPATED ATTM DUE TO FLASH
FLOOD GUIDANCE BEING VERY HIGH. THE RAIN TAPERS OFF FROM W TO E
THUR MIDDAY/AFTERNOON. DECREASING CLOUDS FOR THE REST OF THE DAY
AND NIGHT. COOL N FLOW AT THE SFC WILL ONLY YIELD HIGHS IN THE
L-M50S THUR.
STRONG HIGH PRESSURE BUILDS OVER THE MID ATLANTIC FRI LEADING TO
DRY WX AND SUNNY SKIES. TEMPS WILL ONLY MAX OUT IN THE U40S-L50S AFTER
A CHILLY START IN THE U20S-M30S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LONG RANGE MODELS ARE IN GOOD AGREEMENT WITH SHOWING A SOUTHWEST
UPPER LEVEL FLOW DEVELOPING SATURDAY AS HIGH PRESSURE BECOMES
ANCHORED OVER THE MID ATLANTIC STATES THROUGH SUNDAY. SOME
CLOUDINESS IS POSSIBLE IN NORTHEAST NC AND EXTREME SOUTHEAST VA ON
SATURDAY AS TROPICAL MOISTURE ROTATES AROUND A MID-LEVEL HIGH OFF
THE SOUTHEAST U.S. COAST AND MOVES NEAR THIS AREA. OTHERWISE...A
DRYING AND WARMING TREND IS ANTICIPATED UNDER THIS FLOW
REGIME...WITH HIGH TEMPS REBOUNDING BACK INTO THE 60S BY SUNDAY.
LOWS SHOULD BE NEAR FREEZING SATURDAY MORNING DUE TO PRIME COOLING
CONDITIONS UNDER MOSTLY CLEAR SKIES WITH VERY LIGHT WINDS...THEN
REBOUND TOWARD THE LOW 50S BY EARLY NEXT WEEK AS CLOUDS INCREASE
AHEAD OF THE NEXT WEATHER DISTURBANCE.
BY LATE SUNDAY...A WEAK COLD FRONT IS EXPECTED TO SAG SOUTHWARD AND
STALL OVER THE MID ATLANTIC REGION THROUGH TUESDAY. 12Z MODEL RUNS
TODAY ARE HINTING AT SLOWING THE SOUTHERN MOVEMENT OF THIS BOUNDARY
UNTIL LATE MONDAY...WHICH WOULD DELAY THE ONSET OF PRECIPITATION
UNTIL THAT TIMEFRAME. HAVE TRENDED THE ONGOING FORECAST TOWARD
SLOWING THE PASSAGE OF THE FRONT UNTIL LATE MONDAY...WITH
PRECIPITATION BEING INTRODUCED LATE SUNDAY/EARLY MONDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
COLD FRNT WILL APPROACH THE AREA THRU THIS MORNG...THEN DROP ACRS
THE REGION THIS AFTN THRU TNGT. CIGS/VSBYS WILL QUICKLY LWR TO
MVFR THEN IFR (LIFR?) DURING THIS MORNG WITH -DZ OR SCTD -SHRAS
MOVNG INTO NRN AND WRN AREAS. CIGS/VSBYS WILL LIKELY LIFT TO MVFR
AND VFR CONDITIONS LATER THIS MORNG AND AFTN...AS SW WNDS INCRS IN
ADVANCE OF FRNT...WITH ISLTD TO SCTD SHRAS AHEAD OF AND ALNG THE
FRNTL BNDRY INTO THIS EVENG. DURING THIS EVENG INTO THU
MORNG...IFR (LIFR?) CONDITIONS WITH -RA EXPECTED BEHIND THE FRNT.
VFR AND DRY CONDITIONS WILL RETURN THU AFTN THRU SUN.
&&
.MARINE...
LATEST OBS REFLECTING TIGHTENING PRESSURE GRADIENT BETWEEN HIGH
PRESSURE CENTERED OFF THE SE COAST AND THE COLD FRONT SLOWLY
PUSHING SE FROM THE OHIO VALLEY INTO THE MID-ATLANTIC. THIS
TIGHTENING GRADIENT HAS RESULTED IN SW WINDS 10-15 KT OVER BAY AND
~15-20KT OVER ATLANTIC COASTAL WATERS. WINDS SHOULD REMAIN SUB-
SCA THIS EVENING AND OVERNIGHT INTO EARLY WED WITH THE BUILDING
SOUTH FLOW FROM SW TO NE WED MORN AHEAD OF APPROACHING COLD FRONT
FROM THE NW...WHICH DROPS ACROSS THE REGION WED EVENING. SCA FLAGS
HAVE BEEN HOISTED FOR ENTIRE MARINE AREA W/PRE-FRONTAL SW FLOW
WED AFTN...CONTINUING WITH THE POST-FRONTAL CAA SURGE THU MORNING
INTO THU AFTN. MORE BENIGN MARINE CONDITIONS EXPECTED BY LATE IN
THE WEEK INTO THE WEEKEND AS HIGH PRESSURE BUILDS OVER THE WATERS
FROM THE WEST. HOWEVER...SCA`S FOR HAZARDOUS SEAS MAY BE NEEDED
INTO THE WEEKEND OVER THE COASTAL WATERS WITH GUIDANCE INDICATING
POTENTIAL FOR SEAS TO LINGER IN THE 5-6 FOOT RANGE COURTESY OF
ONSHORE FLOW/LINGERING E-SE SWELL.
&&
.CLIMATE...
RECORD HIGH TEMPS FOR NOV 16TH (WED):
RIC...85 IN 1955
ORF...83 IN 1955
SBY...78 IN 1928
ECG...85 IN 1993
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST THURSDAY FOR
ANZ630>634-650-652-654-656-658.
&&
$$
SYNOPSIS...MAS
NEAR TERM...MAS
SHORT TERM...MAS
LONG TERM...BMD
AVIATION...TMG
MARINE...TMG
CLIMATE...
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
619 PM EST THU NOV 17 2011
LATEST UPDATE...AVIATION...
.SYNOPSIS...(315 PM EST THU NOV 17 2011)
THE LAKE EFFECT SNOW SHOWERS WILL GRADUALLY DIMINISH THIS EVENING.
HIGH PRESSURE OVER THE MIDDLE MISSISSIPPI VALLEY WILL STRENGTHEN AS
IT BUILDS EAST INTO THE CENTRAL APPALACHIANS ON FRIDAY. A GUSTY
SOUTHWESTERLY FLOW WILL SETUP HERE IN LOWER MICHIGAN DURING THE DAY
AND PERSIST INTO SATURDAY. A COLD FRONT WILL SLIP SOUTHEASTWARD
THROUGH THE REGION SATURDAY NIGHT PRODUCING SOME RAIN SHOWERS.
COOLER AIR WILL THEN FILTER IN FOR THE REMAINDER OF THE WEEKEND.
&&
.SHORT TERM...(315 PM EST THU NOV 17 2011)
(TONIGHT THROUGH SATURDAY NIGHT)...
THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE WIND GUSTS ON
FRIDAY.
BUFKIT OVERVIEWS SHOW MIXING HEIGHTS TAPPING INTO THE 40
KNOT WIND RANGE ALONG THE LAKESHORE DURING THE DAY ON FRIDAY. ALSO
FSL RUC DATA SUGGESTS WINDS OVER 40 KNOTS MOVING INLAND DURING THE
DAY. PROFILER DATA FROM THE LOWER PLAINS SHOWS THE LOW
LEVEL JET FORMING AND IT IS ALREADY ABOUT 10 KNOTS STRONGER THAN
FORECASTED. WILL ISSUE A WIND ADVISORY FOR FRIDAY FROM 12Z TO 00Z.
MIXING HEIGHTS LOWER DURING THE EVENING AND THAT SHOULD ALLOW FOR
THE WIND TO DECREASE.
THE TIMING OF THE SHOWERS LATER SATURDAY INTO SATURDAY LOOKS GOOD.
I DID DELAY THE SHOWERS SLIGHTLY GIVEN THE SOMEWHAT SLOWER TREND OF
THE FRONTAL PASSAGE. AS A RESULT I TOOK OUT THE MENTION OF SHOWERS
PRIOR TO 18Z SAT.
A DECENT WARMUP IS IN STORE FOR THE REGION ON SATURDAY. LOW LEVEL
THERMAL PROFILES SUPPORT HIGHS TOPPING 50 DEGREES.
&&
.LONG TERM...(315 PM EST THU NOV 17 2011)
(SUNDAY THROUGH THANKSGIVING DAY)
THE LONG TERM PORTION OF THE FCST LOOKS RATHER TRANQUIL...ESPECIALLY
BY MID-LATE NOVEMBER STANDARDS FOR MICHIGAN. WE WILL HAVE TO WATCH A
POSSIBLE SYSTEM THAT COULD STILL IMPACT AT LEAST A PORTION OF THE
AREA TUE INTO TUE NIGHT.
FRONTAL SYSTEM MOVING THROUGH SAT/SAT NIGHT STILL APPEARS TO JUST
CLEAR THE CWFA BY 12Z SUN. DRY NE FLOW AROUND THE INCOMING SFC RIDGE
AND NOT SO COLD TEMPS /H850 TEMPS 0 TO -2C/ WILL BRING QUIET AND
SEASONABLE TEMPS TO THE AREA. WE ARE EXPECTING THIS HIGH TO RULE
ACROSS THE AREA AT LEAST THROUGH MON. FOR NOW...WE ARE DISCOUNTING
THE 12Z GFS BRINGING LIGHT PCPN TO THE AREA. IT SEEMS TO BE TRYING
TO PHASE SRN STREAM MOISTURE WITH A WEAK NRN STREAM TROUGH. THE
SETUP LOOKS OVERDONE WITH MOISTURE THIS FAR NORTH AND NOT FAVORABLE
FOR PCPN ON MON FOR NOW.
THE TRENDS IN THE MODELS ARE TO HAVE THE SYSTEM FOR TUE/WED A LITTLE
FURTHER NORTH THAN WAS EXPECTED 24 HOURS AGO. WE CAN NOT DISCOUNT
THIS IDEA EXPECTING IT MAY BE A LITTLE STRONGER THAN WHAT IS BEING
SAMPLED NOW. HOWEVER UNLESS THERE IS GOOD PHASING BETWEEN THE TWO
STREAMS...IT SHOULD CONTINUE TO MAINLY MISS THE AREA. THE 00Z EURO
WAS QUITE THE OUTLIER WITH A CLOSED NRN STREAM LOW PHASING WITH THE
SRN STREAM...AND BRINGING A LOT OF PCPN TO THE AREA TUE/WED. THE NEW
EURO HAS BACKED AWAY FROM THAT THINKING...AND IS CLOSER TO THE
ENSEMBLES. IN COORDINATION WITH SURROUNDING OFFICES...WE HAVE ADDED
A SMALL CHC OF PCPN TUE AND TUE NIGHT DOWN SOUTH FOR NOW...AND WILL
CONTINUE TO MONITOR THE TRENDS.
ALL OF THE MODELS HAVE A FAIRLY GOOD RIDGE THEN BUILDING OVER THE
AREA FOR WED AND THANKSGIVING DAY AS ANOTHER STRONG TROUGH TAKES
SHAPE ALONG THE WEST COAST. THIS SHOULD ALLOW FOR MORE SEASONABLE TO
SLIGHTLY ABOVE AVERAGE TEMPS FOR NOVEMBER ALONG WITH DRY CONDITIONS
FOR THE FIRST PART OF THE HOLIDAY TRAVEL PERIOD FOR MICHIGAN.
&&
.AVIATION...(619 PM EST THU NOV 17 2011)
VFR CONDITIONS THROUGH FRIDAY AFTERNOON...BUT BECOMING WINDY. LAKE
EFFECT SNOW SHOWERS WILL END EARLY THIS EVENING AND CLOUDS WILL
BEGIN TO BREAK UP BY 06Z. WINDS WILL GO SOUTHWEST THEN SOUTH ON
FRIDAY MORNING AND INCREASE TO NEAR 20 KNOTS WITH GUSTS OVER 30
KNOTS BY 18Z FRIDAY. THESE STRONG WINDS WILL CONTINUE INTO FRIDAY
EVENING.
&&
.MARINE...(315 PM EST THU NOV 17 2011)
THE ARRIVAL OF A LOW LEVEL JET COUPLED WITH INCREASED MIXING ON
FRIDAY SUPPORTS KEEPING THE GALE WARNING FOR FRIDAY. MIXING
HEIGHTS SUGGEST THE NEARSHORE ZONES WILL REACH INTO THE 40 KNOT
RANGE OF WINDS FRIDAY. THE LOW LEVEL JET AND INCREASED MIXING
PERSISTS THROUGH 00Z SAT...THUS I WILL KEEP THE WARNING GOING
THROUGH MUCH OF THE NIGHT.
&&
.HYDROLOGY...(315 PM EST WED NOV 16 2011)
ANY QPF THROUGH THE PERIOD IS FORECASTED TO BE RELATIVELY LIGHT. AS
A RESULT... NO HYDRO ISSUES ANTICIPATED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY FOR THE LAKESHORE COUNTIES FRIDAY.
LM...SMALL CRAFT ADVISORY ALL NEARSHORE ZONES THROUGH TONIGHT.
GALE WARNING FRIDAY INTO FRIDAY NIGHT ALL NEARSHORE ZONES.
&&
$$
SYNOPSIS: MJS
SHORT TERM: MJS
LONG TERM: NJJ
AVIATION: OSTUNO
MARINE: MJS
HYDROLOGY: MJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EST WED NOV 16 2011
.SHORT TERM /TONIGHT AND THURSDAY/...
POTENT SHORTWAVE THAT MOVED THROUGH THE CWA LAST NIGHT WILL CONTINUE
NE THROUGH QUEBEC TONIGHT...LEAVING THE AREA UNDER AN UPPER TROUGH
FOR MUCH OF THE SHORT TERM PERIOD. LOW/MID LVL MOISTURE BEHIND THE
WAVE HAS SETTLED OVER THE NE HALF OF THE CWA TODAY AND IS EXPECTED
TO REMAIN THROUGH THE FIRST HALF OF THURS. THIS HAS AIDED SOME
SHOWER DEVELOPMENT OVER THE ERN LK THROUGH THE DAY. THESE BANDS HAVE
A NW TO SE APPEARANCE DUE TO THE NW WINDS ALOFT...BUT THE LLVL WINDS
W TO WNW WINDS HAVE BEEN GRADUALLY PUSHING THEM E. DRIER LLVL AIR
OVER WRN LK SUPERIOR HAS TRIED TO LIMIT LES EXTENT OVER THE WRN
U.P...BUT AN ADDITIONAL AREA OF LOW/MID LVL MOISTURE OVER NRN MN
/PRODUCING SCATTERED SHSN/ SHOULD BEGIN TO MOVE INTO THE AREA THIS
EVENING.
WITH THE AREA BETWEEN THE HIGH TO THE SW AND THE EXITING LOW IN
QUEBEC...EXPECT WNW FLOW TO CONTINUE THROUGH THURS. A LINGERING
TROUGH FROM THE EXITING LOW OVER ERN LK SUPERIOR FOR TONIGHT INTO
THURSDAY WILL HELP TO FOCUS WINDS A LITTLE MORE OUT OF THE NW OVER
NRN LUCE AND FAR ERN ALGER COUNTY AND INCREASE THE LLVL CONVERGENCE
IN THAT AREA. RUC ANALYSIS OF H850 TEMPS SHOWS VALUES RANGING FROM
-11C OVER WRN LK SUPERIOR TO -8C OVER ERN LK SUPERIOR. THESE TEMPS
SHOULD FALL A COUPLE DEGREES BY 12Z THURS WITH THE SECONDARY SURGE
OF COLD AIR BEHIND A WEAK H850 TROUGH AND REMAIN THROUGH THE DAY
THURS. THIS CREATES DELTA-T VALUES IN THE UPPER TEENS ACROSS THE LK
THROUGH THE PERIOD.
OVER THE W...PARAMETERS HAVE REALLY COME TOGETHER FOR MODERATE TO
POTENTIALLY HEAVY LES TONIGHT INTO TOMORROW MORNING. WITH THE
SLIGHTLY COLDER H850 TEMPS THERE...EXPECT MUCH OF THE LK INDUCED
FORCING TO BE RIGHT IN THE DGZ. MODELS STILL HINTING AT LLVL DRY AIR
OVER THE WRN CWA KEEPING CLOUD BASES NEAR 3KFT THROUGH THIS
EVENING...WHICH WILL LIMIT THE DEPTH OF THE CLOUD WITH EQL VALUES
FROM 7-10KFT. BUT H925-850 MOISTURE CURRENTLY LOCATED OVER NRN MN
SHOULD PUSH OVER WRN LK SUPERIOR AND THE WRN CWA OVERNIGHT TONIGHT
AND INTO TOMORROW MORNING. THIS SHOULD PROVIDED ADDITIONAL LLVL
MOISTURE TO REALLY ENHANCE THE LES IN THE WNW FAVORED LOCATIONS. LES
PARAMETER IS SHOWING THIS WELL...WITH A DIMINISHING TREND LATE THIS
AFTN AND INTO THE EVENING...BEFORE GREATLY INCREASING OVERNIGHT AND
INTO THURS MORNING. BIGGEST CONCERN IS THE WHAT THE EQL WILL BE.
BUFKIT SOUNDINGS DO HAVE SOME VARIABILITY ON IF THE EQL/S WILL RISE
TOWARDS 12-15KFT OVERNIGHT INTO THURS MORNING...WHICH DEPENDS ON A
DEGREE F OR TWO DIFFERENCE IN THE LK TEMPS. IF THAT OCCURS...COULD
SEE SNOW AMOUNTS BEING HIGHER THAN EXPECTED. FELT THE CURRENT
FORECAST WAS ON TRACK WITH HIGH END ADVISORY AMOUNTS WHERE THERE
WILL LIKELY BE ENHANCED CONVERGENCE OVER NRN ONTONAGON AND CENTRAL
HOUGHTON COUNTIES. THE EVENING SHIFT WILL NEED TO MONITOR TRENDS AND
IF THE SNOW BECOMES HEAVY EARLIER THAN EXPECTED...MAY NEED TO BUMP
UP THE ADVY TO A WARNING.
OVER THE E...WITH THE DEEPER MOISTURE AND EQL NEAR 15KFT FROM THE
EXITING WAVE...LES PARAMETERS ARE MUCH BETTER IN THIS AREA AND
SHOWING POTENTIAL FOR MODERATE TO HEAVY SNOW. THERE POTENTIALLY TWO
LIMITING FACTORS ON SNOW AMOUNTS REACHING WARNING CRITERIA.
FIRST...PREVIOUS SHIFT MENTIONED THE POTENTIAL FOR SNOW PELLETS OR
GRAUPEL AT TIMES TONIGHT...WHICH SEEMS REASONABLE THIS EVENING WITH
THE SLIGHTLY WARMER H850 TEMPS KEEPING THE BEST OMEGA BELOW THE DGZ.
BUT...AS TEMPS COOL OVERNIGHT BEHIND THE H850 TROUGH...EXPECT A
TRANSITION TO MAINLY SNOW. SECOND...THE WIND DIRECTION REMAINS A
CONCERN FOR TONIGHT. WITH NW WINDS SHIFTING MORE WRLY THROUGH THE
DAY TODAY...THE MAIN PCPN HAS BEEN RUNNING NEARLY PARALLEL TO SHORE
THIS AFTN. MODELS SHOW A SLIGHT WNW SHIFT TO THE H925 WINDS THIS
EVENING...BUT NOT SURE IF THIS WILL BE ENOUGH TO SLIDE THE DOMINATE
BAND ONSHORE FROM GRAND MARAIS EAST ALONG THE LUCE COUNTY SHORELINE.
WITH THE GEM/ECMWF/GFS AND LOCAL WRF SHOWING THE LINGERING SFC
TROUGH TIGHTENING UP OVER THE FAR ERN LK OVERNIGHT TONIGHT AND
DROPPING SE THURS MORNING...EXPECT THIS TO SHIFT THE WINDS NW ENOUGH
TO PUSH THE DOMINATE BAND INTO LUCE COUNTY. THUS...WITH
MODERATE/HEAVY SNOW...ALONG WITH GUSTY WINDS UP TO 30MPH...HAVE
SWITCHED THE LES WATCH OVER TO A WARNING FOR LUCE. WITH THE
UNCERTAINTY ON THE EXACT LOCATION OF THE BAND FOR THE GRAND MARAIS
AREA OF ALGER...HAVE SWITCHED THAT WATCH OVER TO AN LES ADVY...BUT
THERE REMAINS SOME BUST POTENTIAL BOTH WAYS. EXPECT THIS PERIOD OF
HEAVY SNOW TO CONTINUE THROUGH THURS MORNING UNDER THE NW WINDS.
CURRENT FORECAST HAS SNOWFALL AMOUNTS EXCEEDING A FOOT FOR PORTIONS
OF NRN LUCE COUNTY BY 00Z FRI.
DRIER MID LVL AIR BEGINS TO MOVE OVER THE SW HALF OF THE CWA THURS
AFTN...LOWERING THE EQL/S TOWARDS 5-6KFT BY 00Z FRI. THIS WILL
DIMINISH THE INTENSITY OF THE SHOWERS OVER THE W. OVER THE E...THESE
LESS FAVORABLE LES CONDITIONS DON/T ARRIVE UNTIL LATE THURS AFTN AND
INTO THURS EVENING AND HAVE ENDED THE WARNING AT 00Z.
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE SFC MAP AT 00Z STRONG HIGH PRESSURE ACROSS THE TN VALLEY WILL
EXTEND A RIDGE ACROSS WI AND WESTERN LAKE SUPERIOR...WITH A WEAK SFC
TROUGH EXTENDING FROM THE MAIN LOW OVER FAR EASTERN CANADA TO JUST
EAST OF LAKE SUPERIOR. THIS WILL ALLOW THE FOCUS FOR HEAVIER SNOW TO
DIMINISH ACROSS LAKE SUPERIOR...WITH NW WINDS BECOMING MORE AND MORE
WESTERLY AS THE EVENING PROGRESSES.
THE HIGH AMPLITUDE 500MB RIDGE OVER THE PACIFIC NORTHWEST AND
WESTERN CANADA WILL FLATTEN AS IT SLIDES ACROSS THE NORTHERN PLAINS
AND SOUTHERN MANITOBA BY 00Z FRIDAY. IT WILL STILL BE ENOUGH TO AT
LEAST TEMPORARILY SWEEP THE TROUGHS EAST OF THE AREA THURSDAY NIGHT
THROUGH THE START OF THE WEEKEND. HOWEVER...THE MAIN CULPRIT WILL
BUDGE LITTLE OVER THE SECOND HALF OF THE WORK WEEK...THAT BEING THE
500MB LOW SPINNING NEAR HUDSON BAY.
THE FAST SOUTHWESTERLY FLOW WILL RETURN...WITH THE APEX OF THE RIDGE
EXITING THE UPPER GREAT LAKES FRIDAY AFTERNOON/EVENING. ONE TROUGH
OVER NORTHERN MANITOBA AT 00Z SATURDAY SHOULD CROSS ONTARIO SATURDAY
AFTERNOON/EVENING. BEHIND THIS FEATURE A MORE DISTINCT TROUGH WILL
WASH OUT ALONG THE CANADIAN/U.S. BORDER...WITH A BROAD TROUGH
EXPECTED ACROSS LAKE SUPERIOR AND UPPER MI SATURDAY EVENING THROUGH
NEXT TUESDAY NIGHT. THE RESULT AT THE SFC WILL BE THE WEAKENING OF
THE 995MB SFC LOW CENTERED ACROSS SOUTHERN SASKATCHEWAN AT 00Z
FRIDAY...TO 1003MB BY 00Z SATURDAY JUST NW OF LAKE SUPERIOR. EVEN
WITH THE WEAKENING OF THIS SYSTEM THE TIGHTENING PRESSURE GRADIENT
WILL RESULT IN STRONGER SW WINDS AT THE SFC FRIDAY INTO EARLY FRIDAY
EVENING...MAINLY ACROSS THE EASTERN HALF OF THE CWA. THE RESULT WILL
BE A TROUGH OF LOW PRESSURE AT THE SFC EXTENDING BETWEEN 2 STRONGER
LOW OVER HUDSON BAY AND KANSAS AT 12Z SATURDAY OVER THE EAST HALF.
LOOK FOR A LOW TO PUSH NORTHEASTWARD ALONG THIS TROUGH FROM THE
CENTRAL TO SOUTHERN PLAINS. MODELS CONTINUE TO PLAY THE LOW TRACKING
NEAR THE STRAITS AROUND 06Z SUNDAY...WITH THE NAM FARTHEST
NORTH...AND THE ECMWF ON THE SOUTHERN END OF THE FORECAST ENVELOP.
THE CANADIAN LOOKS TO BE ABOUT 6 HOURS SLOW. MODERATE TO HEAVY SNOW
ACCUMULATIONS REMAIN POSSIBLE OVER THE WESTERN HALF OF UPPER MI
UNTIL HIGH PRESSURE BUILDS IN FROM THE WEST SUNDAY AFTERNOON.
LOOKING A BIT FARTHER OUT...THERE ARE A COUPLE OF 500MB WAVES WITHIN
THE BROAD TROUGH /WESTERLY FLOW/ THAT ARE DIFFICULT TO FORECAST. THE
FIRST WAVE FOR MONDAY IS MORE DISTINCT OFF THE 16/12Z RUN OF THE
GFS...BUT IS SIMILAR TIMING WISE...BUT IS MUCH WEAKER THAN WHAT IS
SHOWN OFF THE 16/00Z ECMWF. THE CANADIAN IS OUT OF PHASE WITH THE
GFS AND ECMWF STARTING AROUND 12Z MONDAY...OR ABOUT 6 HOURS SLOWER.
A SIMILAR TREND WAS NOTED WITH THE TUESDAY AFTERNOON/EVENING WEAK
TROUGH...WHERE THE GFS TIGHTENED UP THE TROUGH A BIT MORE THAN THE
ECMWF. FORECAST MODELS ARE ABOVE NORMAL CONSISTENCY WISE FOR NEXT
WEDNESDAY...WITH A LARGE 500MB RIDGE BUILDING IN FROM THE PLAINS
STATES.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
COLD AIR MOVING ACROSS LAKE SUPERIOR WILL PRODUCE CLOUDS AND LAKE
EFFECT SNOW FOR THE WEST TO NORTHWEST WIND SNOW BELTS FOR THE TAF
PERIOD. THIS WILL LARGELY AFFECT KCMX WITH PERIODS OF MVFR CIGS AND
IFR VSBYS. WITH KIWD NOT BEING UNDER FAVORABLE FLOW FOR SNOW...HAVE
LEFT OUT MENTION...BUT DID KEEP MVFR CIGS FOR THE OVERNIGHT PERIOD
FROM MOISTURE CURRENTLY IN NRN MN. KSAW WILL MAINLY SEE VFR
CONDITIONS...BUT COULD SEE SOME BRIEF MVFR CIGS LATE TONIGHT INTO
TOMORROW MORNING FROM STRONGER LAKE EFFECT SNOW BANDS OVER NORTHERN
ONTONAGON COUNTY.
&&
.MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/...
LOW PRESSURE ACROSS CENTRAL ONTARIO WILL KEEP A WEAK TROUGH ACROSS
EASTERN LS OVERNIGHT...WHICH WILL ASSIST IN FOCUSING THE STRONGER
GALE FORCE WINDS OF 35KTS OVER THE EASTERN HALF OF LS THROUGH THIS
EVENING. LOOK FOR A RIDGE OF HIGH PRESSURE TO BUILD IN THURSDAY INTO
THURSDAY NIGHT...WITH GUSTS CONTINUING 20 TO 30KTS. LOW PRESSURE
ACROSS SOUTHERN SASKATCHEWAN THURSDAY NIGHT WILL FILL SLIGHTLY JUST
NORTH OF LS FRIDAY NIGHT. AHEAD OF THIS FEATURE...STRONG SW WINDS
FRIDAY INTO FRIDAY NIGHT MAY RESULT IN A FEW GALE FORCE GUSTS ACROSS
EASTERN LS. EXPECT A NEARLY STATIONARY TROUGH OVER EASTERN LS ON
SATURDAY. LOW PRESSURE OVER THE CENTRAL PLAINS SATURDAY WILL MOVE
ALONG THE TROUGH...FILLING SLIGHTLY ACROSS NORTHERN LOWER MICHIGAN
BY SATURDAY NIGHT...WITH A BRIEF PERIOD OF NE GALES TO 35KT SATURDAY
AFTERNOON THAT MAY TRANSITION ACROSS THE ENTIRE LAKE AS WINDS TURN
MORE NORTHWESTERLY AS THE LOW EXITS NE. HIGH PRESSURE SHOULD SLIDE
IN FROM THE WEST SUNDAY...BEFORE SLOWLY DIPPING TO THE LOWER GREAT
LAKES ON MONDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THURSDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WARNING FROM 10 PM THIS EVENING TO 7 PM EST
THURSDAY FOR MIZ007.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 5 PM EST
THURSDAY FOR MIZ006.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>251-265>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...SRF
MARINE...SRF/SF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EST WED NOV 16 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BROAD CYCLONIC FLOW ACROSS
MOST OF THE CONUS WITH AXIS ROUGHLY OVER THE WRN PLAINS. A VIGOROUS
LOOKING SHORTWAVE IS TRACKING THRU THE UPPER GREAT LAKES ATTM. LIKE
ITS PREDECESSOR 24-30HRS AGO...THIS SYSTEM PRODUCED SOME LIGHTNING
STRIKES ACROSS LAKE SUPERIOR EARLIER IN THE NIGHT. THE MORE
SIGNIFICANT PCPN WITH WAVE HAS PASSED MOSTLY N OF UPPER MI...
JUST N OF THE VORT TRACK ACROSS NRN UPPER MI/SRN LAKE SUPERIOR.
UPSTREAM...850MB TEMPS RANGE FROM -7C AT KINL TO -10C KBIS AND -12C
AT CYQD. WHILE 00Z KBIS SOUNDING SHOWED DRYNESS IN THE BOUNDARY
LAYER...KINL AND CQYD SOUNDINGS SHOWED DEEP MOISTURE...ESPECIALLY
CYQD. THIS UPSTREAM COMBINATION OF COLD AIR/DEEP MOISTURE SUGGESTS
AN ACTIVE LES PERIOD SHOULD BE ON THE WAY OVER THE NEXT 36HRS AS
TROF AXIS TO THE W SHIFTS E.
&&
.DISCUSSION...
FCST CONCERNS INVOLVE LES LOCATION/INTENSITY AND SNOW ACCUMULATIONS
THRU THURSDAY AND THEN POSSIBLE WINTER STORM FOR THE WEEKEND.
GIVEN FAVORABLE INSTABILITY/MOISTURE...SOMEWHAT PUZZLED BY THE
RELATIVELY LIGHT PCPN INDICATED BY THE NAM/GFS FOR THE LES TODAY
THRU THU...BUT THERE MAY BE A REASON. WHILE DEEPER MOISTURE EVIDENT
ON CYQD/KINL SOUNDINGS WILL REACH THE AREA...THE FLOW IN THE
LOW-LEVELS IS MORE WRLY...WHICH MAY SUPPORT SOMEWHAT DRIER AIR IN
THE BOUNDARY LAYER AS SUGGESTED BY THE KBIS SOUNDING. BOTH THE NAM
AND GFS HINT AT THAT...BUT THE NAM/GFS SOUNDINGS AREN`T REALLY THAT
DRY. WITH DEEP MOISTURE UWPARDS OF 8-10KFT AND DGZ DESCENDING MORE
FIRMLY INTO THE CONVECTIVE LAYER UNDER CAA REGIME...HAVE TO BELIEVE
LES WILL BE MORE SIGNIFICANT THAN THE NAM/GFS INDICATE. REGIONAL GEM
IS MUCH MORE AGGRESSIVE WITH PCPN AMOUNTS. WHILE THE NAM HAS 12Z
WED-00Z FRI PCPN AMOUNTS UP TO 0.4 INCHES NW TO 0.5 INCHES ALONG
SHORE E OF MUNISING...THE REGIONAL GEM IS UPWARDS OF 0.8 INCHES NW
TO OVER 2 INCHES E OF MUNISING. SOMETHING BTWN THE TWO EXTREMES IS
PROBABLY REASONABLE...THOUGH THE REGIONAL GEM LOOKS QUITE EXCESSIVE
OVER THE E. AT THIS POINT...WILL KEEP 12-24HR SNOW AMOUNTS JUST
UNDER LES WARNING THRESHOLDS NW DUE TO UNCERTAINTY IN BOUNDARY LAYER
MOISTURE. WITH LOW-LEVEL WINDS ESSENTIALLY W...LES WILL TARGET AREAS
FROM ONTONAGON COUNTY THRU THE KEWEENAW. TO THE E...SLIGHT VEERING
OF WINDS HIGHER IN THE CONVECTIVE LAYER SHOULD TEND TO FOCUS THE SRN
LES BAND ALONG TO JUST INLAND FROM THE SHORE FROM PICTURED ROCKS
EASTWARD. TYPICALLY...THE SRN MOST BAND YIELDS HEAVIEST SNOW RATES
DUE TO LAND BREEZE CONVERGENCE AND THE OVERALL LONG FETCH ACROSS THE
LAKE...ONLY INTERRUPTED BRIEFLY BY THE KEWEENAW. THUS...POTENTIAL
EXISTS FOR VERY IMPRESSIVE SNOW ACCUMULATIONS OVER A SMALL AREA OF
THE E CLOSE TO LAKE SUPERIOR...PROVIDED LES BAND DOES NOT SHIFT
OFFSHORE FREQUENTLY. ALSO...DEEP/VIGOROUS CONVECTION AND RELATIVELY
WARM EARLY SEASON WATER/BOUNDARY LAYER MAY LEAD TO MORE GRAUPEL/SNOW
PELLET TYPE PCPN RATHER THAN LARGE SNOWFLAKES...WHICH WILL REDUCE
SNOW ACCUMULATIONS OVER WHAT COULD BE EXPECTED. HAVE OPTED TO ISSUE
A LAKE EFFECT SNOW WATCH FOR ALGER/LUCE...EMPHASIZING THE AREAS FROM
AROUND GRAND MARAIS EASTWARD. AWAY FROM LES...DRY WEATHER WILL
GENERALLY PREVAIL THRU THU.
LES WILL WIND DOWN/END LATER THU/THU NIGHT AS MID/UPPER TROF SHIFTS
E OF THE AREA AND FLOW BEGINS TO BACK IN ADVANCE OF TROF
AMPLIFICATION OVER THE WRN CONUS. LEAD WAVE AHEAD OF THE WRN TROF
AMPLIFICATION COMBINED WITH STRONG WAA COULD LEAD TO SOME LIGHT PCPN
LATER THU NIGHT/FRI MORNING. LACK OF MOISTURE MAY RESULT IN PCPN
OCCURRING FARTHER N IN THE COLDER AIR WHERE SATURATION THRU THE
COLUMN CAN OCCUR.
SHORTWAVE WILL LIFT OUT OF THE WRN TROF EARLY IN THE WEEKEND. FOR
SEVERAL DAYS...MODELS HAVE SHOWN UNUSUALLY GOOD CONTINUITY ON SFC
LOW TRACK DESPITE BEING WAY OUT IN THE FCST CYCLE. THERE HAVE BEEN
THE EXPECTED INTENSITY/PLACEMENT ISSUES...BUT THEY WERE MINOR WHEN
CONSIDERING THE TIME RANGE INTO THE FCST RUN. FOR 90 TO 108HRS INTO
THE MODEL RUN...TODAYS 00Z ROUND OF MEDIUM RANGE GUIDANCE REMAINS
WELL CLUSTERED ON A LOW TRACK FROM KS TO THE UPPER GREAT LAKES...
SOMEWHERE BTWN CNTRL UPPER MI AND FAR NRN LWR MI/STRAITS AREA. ALL
SUGGEST A HEADLINE SNOW EVENT FOR SOME PART OF THE FCST AREA...
PROBABLY HIGH END ADVY TYPE. THE WRN MOST LOW TRACK (GFS) WOULD
PROVIDE HEAVIEST SNOW OVER NW UPPER MI WHILE THE ERN TRACKS (GLOBAL
GEM/ECMWF) WOULD SPREAD HEAVIEST SNOW OVER MOSTLY THE CNTRL PORTION
OF UPPER MI.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
COLD AIR MOVING ACROSS LAKE SUPERIOR WILL PRODUCE CLOUDS AND LAKE
EFFECT SNOW FOR THE WEST TO NORTHWEST WIND SNOW BELTS FOR THE TAF
PERIOD. THIS WILL LARGELY AFFECT KCMX WITH PERIODS OF MVFR CIGS AND
IFR VSBYS. WITH KIWD NOT BEING UNDER FAVORABLE FLOW FOR SNOW...HAVE
LEFT OUT MENTION...BUT DID KEEP MVFR CIGS FOR THE OVERNIGHT PERIOD
FROM MOISTURE CURRENTLY IN NRN MN. KSAW WILL MAINLY SEE VFR
CONDITIONS...BUT COULD SEE SOME BRIEF MVFR CIGS LATE TONIGHT INTO
TOMORROW MORNING FROM STRONGER LAKE EFFECT SNOW BANDS OVER NORTHERN
ONTONAGON COUNTY.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WESTERLY GALES TO DIMINISH BY THIS EVENING OVR LK SUPERIOR AS
SFC LOW JUST EAST OF LK SUPERIOR HEADS INTO QUEBEC. WINDS REMAIN OUT
OF THE W/NW UP TO 30 KTS THURSDAY INTO THURSDAY NIGHT...THEN BECOME
MORE SOUTHERLY ON FRIDAY AS LOW PRESSURE SYSTEM PASSES TO NORTH OF
LK SUPERIOR. COULD BE MARGINAL SRLY GALES OVR FAR EASTERN SECTIONS
FRIDAY. ACTIVE PATTERN CONTINUES INTO THE UPCOMING WEEKEND AS
ANOTHER LOW OVR THE PLAINS ON SATURDAY TRACKS ACROSS THE LAKE
SUPERIOR REGION SATURDAY NIGHT. NE WINDS COULD REACH GALE FORCE OVR
WESTERN SECTIONS SATURDAY WITH NW GALES THEN POSSIBLE LATE SATURDAY
NIGHT INTO SUNDAY MORNING AS THE LOW PULLS AWAY FM THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 PM EST THURSDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WATCH FROM 7 PM EST THIS EVENING THROUGH
THURSDAY AFTERNOON FOR MIZ006-007.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>251-265>267.
GALE WARNING UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR LSZ162-
244-245.
GALE WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR
LSZ241>243-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...ROLFSON
DISCUSSION...ROLFSON
AVIATION...SRF
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
651 AM EST WED NOV 16 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BROAD CYCLONIC FLOW ACROSS
MOST OF THE CONUS WITH AXIS ROUGHLY OVER THE WRN PLAINS. A VIGOROUS
LOOKING SHORTWAVE IS TRACKING THRU THE UPPER GREAT LAKES ATTM. LIKE
ITS PREDECESSOR 24-30HRS AGO...THIS SYSTEM PRODUCED SOME LIGHTNING
STRIKES ACROSS LAKE SUPERIOR EARLIER IN THE NIGHT. THE MORE
SIGNIFICANT PCPN WITH WAVE HAS PASSED MOSTLY N OF UPPER MI...
JUST N OF THE VORT TRACK ACROSS NRN UPPER MI/SRN LAKE SUPERIOR.
UPSTREAM...850MB TEMPS RANGE FROM -7C AT KINL TO -10C KBIS AND -12C
AT CYQD. WHILE 00Z KBIS SOUNDING SHOWED DRYNESS IN THE BOUNDARY
LAYER...KINL AND CQYD SOUNDINGS SHOWED DEEP MOISTURE...ESPECIALLY
CYQD. THIS UPSTREAM COMBINATION OF COLD AIR/DEEP MOISTURE SUGGESTS
AN ACTIVE LES PERIOD SHOULD BE ON THE WAY OVER THE NEXT 36HRS AS
TROF AXIS TO THE W SHIFTS E.
&&
.DISCUSSION...
FCST CONCERNS INVOLVE LES LOCATION/INTENSITY AND SNOW ACCUMULATIONS
THRU THURSDAY AND THEN POSSIBLE WINTER STORM FOR THE WEEKEND.
GIVEN FAVORABLE INSTABILITY/MOISTURE...SOMEWHAT PUZZLED BY THE
RELATIVELY LIGHT PCPN INDICATED BY THE NAM/GFS FOR THE LES TODAY
THRU THU...BUT THERE MAY BE A REASON. WHILE DEEPER MOISTURE EVIDENT
ON CYQD/KINL SOUNDINGS WILL REACH THE AREA...THE FLOW IN THE
LOW-LEVELS IS MORE WRLY...WHICH MAY SUPPORT SOMEWHAT DRIER AIR IN
THE BOUNDARY LAYER AS SUGGESTED BY THE KBIS SOUNDING. BOTH THE NAM
AND GFS HINT AT THAT...BUT THE NAM/GFS SOUNDINGS AREN`T REALLY THAT
DRY. WITH DEEP MOISTURE UWPARDS OF 8-10KFT AND DGZ DESCENDING MORE
FIRMLY INTO THE CONVECTIVE LAYER UNDER CAA REGIME...HAVE TO BELIEVE
LES WILL BE MORE SIGNIFICANT THAN THE NAM/GFS INDICATE. REGIONAL GEM
IS MUCH MORE AGGRESSIVE WITH PCPN AMOUNTS. WHILE THE NAM HAS 12Z
WED-00Z FRI PCPN AMOUNTS UP TO 0.4 INCHES NW TO 0.5 INCHES ALONG
SHORE E OF MUNISING...THE REGIONAL GEM IS UPWARDS OF 0.8 INCHES NW
TO OVER 2 INCHES E OF MUNISING. SOMETHING BTWN THE TWO EXTREMES IS
PROBABLY REASONABLE...THOUGH THE REGIONAL GEM LOOKS QUITE EXCESSIVE
OVER THE E. AT THIS POINT...WILL KEEP 12-24HR SNOW AMOUNTS JUST
UNDER LES WARNING THRESHOLDS NW DUE TO UNCERTAINTY IN BOUNDARY LAYER
MOISTURE. WITH LOW-LEVEL WINDS ESSENTIALLY W...LES WILL TARGET AREAS
FROM ONTONAGON COUNTY THRU THE KEWEENAW. TO THE E...SLIGHT VEERING
OF WINDS HIGHER IN THE CONVECTIVE LAYER SHOULD TEND TO FOCUS THE SRN
LES BAND ALONG TO JUST INLAND FROM THE SHORE FROM PICTURED ROCKS
EASTWARD. TYPICALLY...THE SRN MOST BAND YIELDS HEAVIEST SNOW RATES
DUE TO LAND BREEZE CONVERGENCE AND THE OVERALL LONG FETCH ACROSS THE
LAKE...ONLY INTERRUPTED BRIEFLY BY THE KEWEENAW. THUS...POTENTIAL
EXISTS FOR VERY IMPRESSIVE SNOW ACCUMULATIONS OVER A SMALL AREA OF
THE E CLOSE TO LAKE SUPERIOR...PROVIDED LES BAND DOES NOT SHIFT
OFFSHORE FREQUENTLY. ALSO...DEEP/VIGOROUS CONVECTION AND RELATIVELY
WARM EARLY SEASON WATER/BOUNDARY LAYER MAY LEAD TO MORE GRAUPEL/SNOW
PELLET TYPE PCPN RATHER THAN LARGE SNOWFLAKES...WHICH WILL REDUCE
SNOW ACCUMULATIONS OVER WHAT COULD BE EXPECTED. HAVE OPTED TO ISSUE
A LAKE EFFECT SNOW WATCH FOR ALGER/LUCE...EMPHASIZING THE AREAS FROM
AROUND GRAND MARAIS EASTWARD. AWAY FROM LES...DRY WEATHER WILL
GENERALLY PREVAIL THRU THU.
LES WILL WIND DOWN/END LATER THU/THU NIGHT AS MID/UPPER TROF SHIFTS
E OF THE AREA AND FLOW BEGINS TO BACK IN ADVANCE OF TROF
AMPLIFICATION OVER THE WRN CONUS. LEAD WAVE AHEAD OF THE WRN TROF
AMPLIFICATION COMBINED WITH STRONG WAA COULD LEAD TO SOME LIGHT PCPN
LATER THU NIGHT/FRI MORNING. LACK OF MOISTURE MAY RESULT IN PCPN
OCCURRING FARTHER N IN THE COLDER AIR WHERE SATURATION THRU THE
COLUMN CAN OCCUR.
SHORTWAVE WILL LIFT OUT OF THE WRN TROF EARLY IN THE WEEKEND. FOR
SEVERAL DAYS...MODELS HAVE SHOWN UNUSUALLY GOOD CONTINUITY ON SFC
LOW TRACK DESPITE BEING WAY OUT IN THE FCST CYCLE. THERE HAVE BEEN
THE EXPECTED INTENSITY/PLACEMENT ISSUES...BUT THEY WERE MINOR WHEN
CONSIDERING THE TIME RANGE INTO THE FCST RUN. FOR 90 TO 108HRS INTO
THE MODEL RUN...TODAYS 00Z ROUND OF MEDIUM RANGE GUIDANCE REMAINS
WELL CLUSTERED ON A LOW TRACK FROM KS TO THE UPPER GREAT LAKES...
SOMEWHERE BTWN CNTRL UPPER MI AND FAR NRN LWR MI/STRAITS AREA. ALL
SUGGEST A HEADLINE SNOW EVENT FOR SOME PART OF THE FCST AREA...
PROBABLY HIGH END ADVY TYPE. THE WRN MOST LOW TRACK (GFS) WOULD
PROVIDE HEAVIEST SNOW OVER NW UPPER MI WHILE THE ERN TRACKS (GLOBAL
GEM/ECMWF) WOULD SPREAD HEAVIEST SNOW OVER MOSTLY THE CNTRL PORTION
OF UPPER MI.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/
COLD AIR MOVING INTO THE REGION ON WEST NORTHWEST WINDS BEHIND A
SHORTWAVE TROUGH AND SFC LOW WILL SUPPORT LAKE EFFECT SNOW THROUGH
THE PERIOD AT CMX. FOR THE MAJORITY OF THE TIME AT CMX...EXPECT
LOWER MVFR CIGS WITH MAINLY IFR VSBY. MEANWHILE AT IWD AND
SAW...WESTERLY LOW LEVEL WINDS ARE NOT FAVORABLE FOR LAKE EFFECT
SNOW...SO LITTLE IN WAY OF VSBY REDUCTION IS EXPECTED. COULD SEE
OCCASIONAL CIGS AT OR NEAR MVFR AT IWD AND SAW THOUGH.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WESTERLY GALES TO DIMINISH BY THIS EVENING OVR LK SUPERIOR AS
SFC LOW JUST EAST OF LK SUPERIOR HEADS INTO QUEBEC. WINDS REMAIN OUT
OF THE W/NW UP TO 30 KTS THURSDAY INTO THURSDAY NIGHT...THEN BECOME
MORE SOUTHERLY ON FRIDAY AS LOW PRESSURE SYSTEM PASSES TO NORTH OF
LK SUPERIOR. COULD BE MARGINAL SRLY GALES OVR FAR EASTERN SECTIONS
FRIDAY. ACTIVE PATTERN CONTINUES INTO THE UPCOMING WEEKEND AS
ANOTHER LOW OVR THE PLAINS ON SATURDAY TRACKS ACROSS THE LAKE
SUPERIOR REGION SATURDAY NIGHT. NE WINDS COULD REACH GALE FORCE OVR
WESTERN SECTIONS SATURDAY WITH NW GALES THEN POSSIBLE LATE SATURDAY
NIGHT INTO SUNDAY MORNING AS THE LOW PULLS AWAY FM THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 PM EST THURSDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH THURSDAY
AFTERNOON FOR MIZ006-007.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>251-265>267.
GALE WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR LSZ162-
241>243-263-264.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ244-245.
LAKE MICHIGAN...
GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LMZ221-250.
&&
$$
SYNOPSIS...ROLFSON
DISCUSSION...ROLFSON
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
549 AM EST WED NOV 16 2011
.SYNOPSIS...
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BROAD CYCLONIC FLOW ACROSS
MOST OF THE CONUS WITH AXIS ROUGHLY OVER THE WRN PLAINS. A VIGOROUS
LOOKING SHORTWAVE IS TRACKING THRU THE UPPER GREAT LAKES ATTM. LIKE
ITS PREDECESSOR 24-30HRS AGO...THIS SYSTEM PRODUCED SOME LIGHTNING
STRIKES ACROSS LAKE SUPERIOR EARLIER IN THE NIGHT. THE MORE
SIGNIFICANT PCPN WITH WAVE HAS PASSED MOSTLY N OF UPPER MI...
JUST N OF THE VORT TRACK ACROSS NRN UPPER MI/SRN LAKE SUPERIOR.
UPSTREAM...850MB TEMPS RANGE FROM -7C AT KINL TO -10C KBIS AND -12C
AT CYQD. WHILE 00Z KBIS SOUNDING SHOWED DRYNESS IN THE BOUNDARY
LAYER...KINL AND CQYD SOUNDINGS SHOWED DEEP MOISTURE...ESPECIALLY
CYQD. THIS UPSTREAM COMBINATION OF COLD AIR/DEEP MOISTURE SUGGESTS
AN ACTIVE LES PERIOD SHOULD BE ON THE WAY OVER THE NEXT 36HRS AS
TROF AXIS TO THE W SHIFTS E.
&&
.DISCUSSION...
FCST CONCERNS INVOLVE LES LOCATION/INTENSITY AND SNOW ACCUMULATIONS
THRU THURSDAY AND THEN POSSIBLE WINTER STORM FOR THE WEEKEND.
GIVEN FAVORABLE INSTABILITY/MOISTURE...SOMEWHAT PUZZLED BY THE
RELATIVELY LIGHT PCPN INDICATED BY THE NAM/GFS FOR THE LES TODAY
THRU THU...BUT THERE MAY BE A REASON. WHILE DEEPER MOISTURE EVIDENT
ON CYQD/KINL SOUNDINGS WILL REACH THE AREA...THE FLOW IN THE
LOW-LEVELS IS MORE WRLY...WHICH MAY SUPPORT SOMEWHAT DRIER AIR IN
THE BOUNDARY LAYER AS SUGGESTED BY THE KBIS SOUNDING. BOTH THE NAM
AND GFS HINT AT THAT...BUT THE NAM/GFS SOUNDINGS AREN`T REALLY THAT
DRY. WITH DEEP MOISTURE UWPARDS OF 8-10KFT AND DGZ DESCENDING MORE
FIRMLY INTO THE CONVECTIVE LAYER UNDER CAA REGIME...HAVE TO BELIEVE
LES WILL BE MORE SIGNIFICANT THAN THE NAM/GFS INDICATE. REGIONAL GEM
IS MUCH MORE AGGRESSIVE WITH PCPN AMOUNTS. WHILE THE NAM HAS 12Z
WED-00Z FRI PCPN AMOUNTS UP TO 0.4 INCHES NW TO 0.5 INCHES ALONG
SHORE E OF MUNISING...THE REGIONAL GEM IS UPWARDS OF 0.8 INCHES NW
TO OVER 2 INCHES E OF MUNISING. SOMETHING BTWN THE TWO EXTREMES IS
PROBABLY REASONABLE...THOUGH THE REGIONAL GEM LOOKS QUITE EXCESSIVE
OVER THE E. AT THIS POINT...WILL KEEP 12-24HR SNOW AMOUNTS JUST
UNDER LES WARNING THRESHOLDS NW DUE TO UNCERTAINTY IN BOUNDARY LAYER
MOISTURE. WITH LOW-LEVEL WINDS ESSENTIALLY W...LES WILL TARGET AREAS
FROM ONTONAGON COUNTY THRU THE KEWEENAW. TO THE E...SLIGHT VEERING
OF WINDS HIGHER IN THE CONVECTIVE LAYER SHOULD TEND TO FOCUS THE SRN
LES BAND ALONG TO JUST INLAND FROM THE SHORE FROM PICTURED ROCKS
EASTWARD. TYPICALLY...THE SRN MOST BAND YIELDS HEAVIEST SNOW RATES
DUE TO LAND BREEZE CONVERGENCE AND THE OVERALL LONG FETCH ACROSS THE
LAKE...ONLY INTERRUPTED BRIEFLY BY THE KEWEENAW. THUS...POTENTIAL
EXISTS FOR VERY IMPRESSIVE SNOW ACCUMULATIONS OVER A SMALL AREA OF
THE E CLOSE TO LAKE SUPERIOR...PROVIDED LES BAND DOES NOT SHIFT
OFFSHORE FREQUENTLY. ALSO...DEEP/VIGOROUS CONVECTION AND RELATIVELY
WARM EARLY SEASON WATER/BOUNDARY LAYER MAY LEAD TO MORE GRAUPEL/SNOW
PELLET TYPE PCPN RATHER THAN LARGE SNOWFLAKES...WHICH WILL REDUCE
SNOW ACCUMULATIONS OVER WHAT COULD BE EXPECTED. HAVE OPTED TO ISSUE
A LAKE EFFECT SNOW WATCH FOR ALGER/LUCE...EMPHASIZING THE AREAS FROM
AROUND GRAND MARAIS EASTWARD. AWAY FROM LES...DRY WEATHER WILL
GENERALLY PREVAIL THRU THU.
LES WILL WIND DOWN/END LATER THU/THU NIGHT AS MID/UPPER TROF SHIFTS
E OF THE AREA AND FLOW BEGINS TO BACK IN ADVANCE OF TROF
AMPLIFICATION OVER THE WRN CONUS. LEAD WAVE AHEAD OF THE WRN TROF
AMPLIFICATION COMBINED WITH STRONG WAA COULD LEAD TO SOME LIGHT PCPN
LATER THU NIGHT/FRI MORNING. LACK OF MOISTURE MAY RESULT IN PCPN
OCCURRING FARTHER N IN THE COLDER AIR WHERE SATURATION THRU THE
COLUMN CAN OCCUR.
SHORTWAVE WILL LIFT OUT OF THE WRN TROF EARLY IN THE WEEKEND. FOR
SEVERAL DAYS...MODELS HAVE SHOWN UNUSUALLY GOOD CONTINUITY ON SFC
LOW TRACK DESPITE BEING WAY OUT IN THE FCST CYCLE. THERE HAVE BEEN
THE EXPECTED INTENSITY/PLACEMENT ISSUES...BUT THEY WERE MINOR WHEN
CONSIDERING THE TIME RANGE INTO THE FCST RUN. FOR 90 TO 108HRS INTO
THE MODEL RUN...TODAYS 00Z ROUND OF MEDIUM RANGE GUIDANCE REMAINS
WELL CLUSTERED ON A LOW TRACK FROM KS TO THE UPPER GREAT LAKES...
SOMEWHERE BTWN CNTRL UPPER MI AND FAR NRN LWR MI/STRAITS AREA. ALL
SUGGEST A HEADLINE SNOW EVENT FOR SOME PART OF THE FCST AREA...
PROBABLY HIGH END ADVY TYPE. THE WRN MOST LOW TRACK (GFS) WOULD
PROVIDE HEAVIEST SNOW OVER NW UPPER MI WHILE THE ERN TRACKS (GLOBAL
GEM/ECMWF) WOULD SPREAD HEAVIEST SNOW OVER MOSTLY THE CNTRL PORTION
OF UPPER MI.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/
COLD AIR MOVING INTO THE REGION ON WEST NORTHWEST WINDS BEHIND A
SHORTWAVE TROUGH AND LOW WILL SUPPORT LAKE ENHANCED SNOW OVER IWD
AND CMX...WITH CIGS DROPPING INTO THE MVFR RANGE AND OCNL IFR VSBY.
EXPECT SOME IMPROVEMENT AT IWD TOWARDS MID DAY AS MORE WESTERLY FLOW
PUSHES THE BEST SNOW ACTIVITY NORTH OF THE TAF SITE. AT KCMX...MORE
PERSISTENT LOWER MVFR OR NEAR IFR CONDITIONS ARE EXPECTED AS THE
LAKE EFFECT/ENHANCED SNOW CONTINUES. LOW LEVEL WINDS TOWARD KSAW
WILL BE LESS FAVORABLE FOR LAKE EFFECT PCPN...BUT MAY SEE CIGS AT OR
NEAR MVFR.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT WESTERLY GALES TO DIMINISH BY THIS EVENING OVR LK SUPERIOR AS
SFC LOW JUST EAST OF LK SUPERIOR HEADS INTO QUEBEC. WINDS REMAIN OUT
OF THE W/NW UP TO 30 KTS THURSDAY INTO THURSDAY NIGHT...THEN BECOME
MORE SOUTHERLY ON FRIDAY AS LOW PRESSURE SYSTEM PASSES TO NORTH OF
LK SUPERIOR. COULD BE MARGINAL SRLY GALES OVR FAR EASTERN SECTIONS
FRIDAY. ACTIVE PATTERN CONTINUES INTO THE UPCOMING WEEKEND AS
ANOTHER LOW OVR THE PLAINS ON SATURDAY TRACKS ACROSS THE LAKE
SUPERIOR REGION SATURDAY NIGHT. NE WINDS COULD REACH GALE FORCE OVR
WESTERN SECTIONS SATURDAY WITH NW GALES THEN POSSIBLE LATE SATURDAY
NIGHT INTO SUNDAY MORNING AS THE LOW PULLS AWAY FM THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 PM EST THURSDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH THURSDAY
AFTERNOON FOR MIZ006-007.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>251-265>267.
GALE WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR LSZ162-
241>243-263-264.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ244-245.
LAKE MICHIGAN...
GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LMZ221-250.
&&
$$
SYNOPSIS...ROLFSON
DISCUSSION...ROLFSON
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
303 PM CST WED NOV 16 2011
.DISCUSSION...
VERY COLD UPPER TROUGH SWINGING THROUGH THE AREA NOW. H5 TEMPS
AROUND -40 THIS MORNING ABR TO GGW. VERY DRY AIR WITH SINGLE
DIGIT DEW POINTS CURRENTLY OVER OUR SOUTHERN CWA. WILL NEED TO
LOWER MIN TEMPS A BIT TONIGHT. IT DOES LOOK LIKE THERE IS A BACK
EDGE TO THE COLD AIR CU/SC OVER EASTERN ND WITH MUCH OF THE CLOUD
DECK OVER OUR AREA MAINLY CUFORM. THE TREND TOWARD CLEARING LOOKS
GOOD THIS EVENING GIVING A GOOD START TO THE COLD OVERNIGHT MINS.
LOOKS LIKE A COLD DAY FOR THURSDAY..BUT UNDER SUNNY SKIES DUE TO
VERY DRY AIR OVER THE AREA. ATTENTION THEN TURNS TO THE SYSTEM FOR
FRIDAY. SOME DECENT MODERATION AHEAD OF THE NORTHERN STREAM WAVE
AND FRONT CROSSING THE AREA THURSDAY NIGHT AND FRIDAY. THIS SHOULD
ALLOW RECOVERY TO TEMPS NEAR 50 OVER SOUTHERN MN ON FRIDAY. THE
COLD FRONT SHOULD MOVE THROUGH THE AREAS FRIDAY NIGHT AND THEN
STALL JUST TO OUR SOUTH. A TIGHT TEMP GRADIENT WILL SET UP ACROSS
THE AREA ON SATURDAY. THERE HAS BEEN GENERAL CONSISTENCY IN
FOCUSING THE BEST FORCING ACROSS CENTRAL MN INTO THE NORTHERN PART
OF OUR WI AREA. THIS TREND CONTINUING AT LEAST WITH THE GFS AND
ECMWF. THE NAM SEEMS A LITTLE TOO FAR TO THE NORTHWEST. WITH A
SNOW COVER NOW DEVELOPING ACROSS CANADA INTO ND AND PARTS OF N
MN...IT WILL BE INTERESTING TO SEE HOW FAR SOUTH THE FRONT ENDS UP
LATE FRIDAY AND FRIDAY NIGHT. THE COLD LOW LEVEL TEMP STRUCTURE
COULD BE PROBLEMATIC WITH PTYPE..WITH THE OUTSIDE CHANCE OF FZRA
IN A FEW AREAS OF THE SOUTH. WILL NOT TRY TO PIN THAT DOWN AT
THIS POINT...BUT KEEP THE ZONE OF RASN.
HAVE BROUGHT SOME SNOW POTENTIAL A LITTLE FARTHER SOUTH BUT THE
NORTH HALF OF THE CWA STILL SEEMS TO HAVE THE BEST CHANCE. THE
SREF PROBS OB THE BEST DENDRITIC ZONE IS IN NORTHERN MN BUT THIS
IS OUT AT THE LAST FEW TIME STEPS OF THE RUN. IT DOES LOOK LIKE AN
FGEN DRIVEN EVENT WITH THE OPEN WAVE...SO THERE WILL BE POTENTIAL
FOR A SHARP CUT OFF TO PRECIP.
AFTER A COLD PERIOD FOLLOWING THE SYSTEM..IT LOOKS LIKE WE WILL
BE BACK TO A MAINLY MILD PATTERN WITH THE DEEP MEAN TROUGH OVER
AK. THE LATEST NAEFS IS SHOWING A LARGE AREA OF PROBS OF ABOVE
NORMAL TEMPS IN THE EASTERN HALF OF THE COUNTRY..EAST OF THE MO
RIVER.
&&
.AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS HAVE DEVELOPED ALONG THE LEADING EDGE OF DEEPER MOISTURE
MOVING ACROSS WC MN...AND CENTRAL MN. MOST OF THE CLDS ARE
ASSOCIATED WITH A DIURNAL TREND WHICH SHOULD ABATE AFT SUNSET.
HOWEVER...THICKER CLD CVR ACROSS SC ND...AND INTO NE SD MAY ALLOW
FOR THE CLDS TO LINGER INTO THE EVENING. THIS IS THE MAIN AVIATION
CONCERN IN THE SHORT TERM...WITH THE COMMON DIURNAL TREND OF THE
GUSTY W/NW WNDS THIS AFTN. BASED ON UPSTREAM OBS IN SD/ND AND
ACROSS PORTIONS OF WC/C MN...WILL CONTINUE THE HIGH END MVFR CIGS
FOR AXN...AND POSSIBLY STC IF CONDITIONS WARRANT. MOST OF THE
OTHER MPX TAF SITES WILL REMAIN VFR OR AT LEAST HAVE CIGS ABV 3K.
SOME -SN HAS DEVELOPED IN THE PORTIONS OF SC/SE ND WHERE DEEPER
MOISTURE AND ASSOCIATED DENDRITIC ZONE HAS ALLOWED FOR -SN...BUT
COVERAGE WILL REMAIN TOO LOW FOR ANY TYPE OF -SN IN THE AFTN TAF.
WILL MONITOR IF CONDITIONS BECOME MORE SCATTERED/WIDESPREAD AS THE
LATEST RUC IS HINTING ON THIS. WNDS WILL BECOME MORE W/SW
OVERNIGHT...THEN SW/S BY THU MORNING.
MSP...SCT/BKN CLDS ARND 3-3.5K WILL MOVE ACROSS MSP AIRPORT DURING
THE AFTN...BUT WILL CONTINUE WITH VFR CIGS OF 4-5K AT THIS TIME.
WNDS CURRENTLY FROM THE SW...BUT IT SHOULD CHG DURING THE AFTN AS
MIXING DEVELOPS AND ALLOWS FOR SOME GUSTS UP TO 22 KTS FROM THE
WNW. WNDS WILL DECREASE TOWARD SUNSET...THEN BECOME MORE WSW/SW BY
MORNING...BUT REMAIN UNDER 8 KTS.
OUTLOOK FOR SATURDAY STILL LOOKS FAVORABLE FOR MVFR/IFR CIGS/VSBYS
AS A STORM SYSTEM MOVES FROM THE CENTRAL PLAINS/INTO THE UPPER
MIDWEST. TIMING AND TRANSITION FROM RA TO SN WILL REMAIN PROBLEMATIC
/MAINLY SOUTH OF RWF TO MSP AND RNH/...BUT CURRENT TRENDS INDICATE
THAT THE WORSE CONDITIONS WILL BE FROM 18Z/19...TO 06Z/20. OR LATE
SATURDAY AFTN...THRU THE EVENING. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1126 AM CST WED NOV 16 2011
.DISCUSSION...
A COLD WEST-NORTHWEST FLOW OF AIR WILL COVER THE REGION INTO
THURSDAY. A SHORT WAVE OVER NORTH DAKOTA WILL PROGRESS TO THE
WESTERN GREAT LAKES BY TONIGHT. SOME CLOUDINESS OVER CENTRAL
MN AND WEST CENTRAL WI EARLY THIS MORNING WILL PART FOR A TIME
BEFORE ANOTHER SURGE OF LOW CLOUDINESS ARRIVES FOR THE AFTERNOON
AND EVENING HOURS. OUR LOCAL MODEL AND THE RUC PAINT SOME LIGHT
ECHOES ACROSS CENTRAL MN AND WEST CENTRAL WI DURING THE AFTERNOON
AND EVENING HOURS...SO KEPT THE MENTION OF FLURRIES TO THESE
AREAS. THERE SHOULD BE A GOOD DEAL OF SUNSHINE ACROSS SOUTHERN MN
TODAY. THE MIX-DOWN TD TOOL POINTS TO DEW POINT LOWERING TO AROUND
5 DEG C DURING THE AFTERNOON. WE ARE CURRENTLY SEEING SOME SINGLE
DIGIT DEW POINTS NEAR THE SD/NE EARLY THIS MORNING. THE ARW/NMM
WRFS ALSO INDICATE DINGLE DIGIT DEW POINT IN THE SOUTH THIS
AFTERNOON. HENCE...BLENDED IN THE MIX DOWN DPS WITH CONSENSUS FOR
THE AFTERNOON AND EVENING HOURS. TRENDED A FEW DEGREES HIGHER ON
HIGH TEMPERATURES TODAY OVER THE SOUTHERN HALF OF THE CWA VERSUS
MET/MAV MOS DUE TO MORE SUNSHINE AND WHAT THE MIX DOWN MAX T WAS
SHOWING.
FLURRIES/CLOUDS WILL DIMINISH TONIGHT OVER THE NORTHERN AND
EASTERN CWA AS HIGH PRESSURE MOVES IN LATE IN THE NIGHT. THE RIDGE
WILL MOVE ACROSS THE CWA ON THURSDAY WITH FLOW BECOMING MORE
SOUTHERLY. IT WILL STILL BE A COOL DAY WITH HIGHS ONLY IN THE 30S.
AS THE RIDGE MOVES EAST THURSDAY NIGHT...A WARM FRONT WILL DEVELOP
AND MOVE NORTHEAST ACROSS THE CWA. ONLY SOME CLOUDS EXPECTED WITH
THE WARM FRONT. THIS WILL LEAD TO A WARMER FRIDAY WITH HIGHS
REACHING WELL INTO THE 40S IN MOST AREAS WITH SOME 50S IN THE
SOUTH.
THE LOW PRESSURE SYSTEM AND PRECIPITATION EVENT FOR SATURDAY AND
SATURDAY NIGHT REMAINS ON TRACK. THE GEM AND ECMWF ARE IN STEP
WITH THIS SYSTEM WHILE THE GFS LAGS BY ABOUT 6 HOURS. THE GFS
ENSEMBLE IS EVEN SLOWER BY ABOUT ANOTHER 6 HOURS. STILL EXPECT A
LOW TO TRACK FROM EASTERN NEBRASKA SATURDAY MORNING TO EASTERN WI
BY SATURDAY NIGHT. ALL SOLUTIONS INDICATE THE LOW SLOWLY FILLING
DURING THIS PERIOD WHICH IS NOTE GOOD FOR A HEAVY SNOW EVENT. WE
ALSO CONTINUE TO SEE AN OPEN WAVE ALOFT WHICH SPEAKS FOR THE
QUICKNESS WITH THIS SYSTEM. LOOKING AT SOME OF THE MID/UPPER LEVEL
FEATURES SHOWS THE H5 HEIGHT FALL TRACK FROM YELLOW MEDICINE COUNTY
TO BURNETT COUNTY. THE -15 DEG C OMEGA IS ON THE LEFT SIDE OF THIS
TRACK WITH THE DEPTH OF THE DENDRITIC GROWTH ZONE BEING ABOUT
1100M. THE WARM POCKET AT H2 ALSO TRACKS ALONG THE AFOREMENTIONED
AXIS WITH 10 DEG OF WARMING NOTED.
THE 295K THETA SURFACE PLACES 700 MB ABOUT IN THIS GENERAL AREA AS
WELL WITH PLENTY OF SATURATION AND ADIABATIC OMEGA NOTED TO THE
NORTH AND WEST. THE MIX RATIO CONTINUES TO RUN BETWEEN 2 AND 3
G/KG AND IS ALIGNED WITH THE -FN VECTOR DIVERGENCE. THIS ALL POINTS
TO A BAND OF 4 TO LOCALLY 6 INCHES FROM WEST CENTRAL MN ON
NORTHEAST TO DULUTH AND HAYWARD. THE CARIBOU SNOW TOOL USING THE GFS
AGREES PRETTY WELL WITH THIS SCENARIO. ALSO INTERESTING IS THE
16/00Z CIPS DATA...BASED ON THE TOP 15 ANALOGS...WHICH SHOWS MEAN
SNOWFALL OF 4 TO 6 FROM WEST CENTRAL MN THROUGH THE ARROWHEAD AND
FAR NORTHERN AREAS OF WI WITH 2 TO 3 INCHES FROM SOUTHWEST MN
THROUGH THE METRO AND ACROSS MUCH OF WEST CENTRAL WI.
IN THE WAKE OF THE LOW PRESSURE SYSTEM...A RATHER SUBSTANTIAL HIGH
WILL BUILD OVER THE REGION FROM SUNDAY THROUGH TUESDAY WITH DRY
WEATHER AND BELOW NORMAL TEMPERATURES OCCURRING.
&&
.AVIATION.../18Z TAF ISSUANCE/
MVFR CIGS HAVE DEVELOPED ALONG THE LEADING EDGE OF DEEPER MOISTURE
MOVING ACROSS WC MN...AND CENTRAL MN. MOST OF THE CLDS ARE
ASSOCIATED WITH A DIURNAL TREND WHICH SHOULD ABATE AFT SUNSET.
HOWEVER...THICKER CLD CVR ACROSS SC ND...AND INTO NE SD MAY ALLOW
FOR THE CLDS TO LINGER INTO THE EVENING. THIS IS THE MAIN AVIATION
CONCERN IN THE SHORT TERM...WITH THE COMMON DIURNAL TREND OF THE
GUSTY W/NW WNDS THIS AFTN. BASED ON UPSTREAM OBS IN SD/ND AND
ACROSS PORTIONS OF WC/C MN...WILL CONTINUE THE HIGH END MVFR CIGS
FOR AXN...AND POSSIBLY STC IF CONDITIONS WARRANT. MOST OF THE
OTHER MPX TAF SITES WILL REMAIN VFR OR AT LEAST HAVE CIGS ABV 3K.
SOME -SN HAS DEVELOPED IN THE PORTIONS OF SC/SE ND WHERE DEEPER
MOISTURE AND ASSOCIATED DENDRITIC ZONE HAS ALLOWED FOR -SN...BUT
COVERAGE WILL REMAIN TOO LOW FOR ANY TYPE OF -SN IN THE AFTN TAF.
WILL MONITOR IF CONDITIONS BECOME MORE SCATTERED/WIDESPREAD AS THE
LATEST RUC IS HINTING ON THIS. WNDS WILL BECOME MORE W/SW
OVERNIGHT...THEN SW/S BY THU MORNING.
MSP...SCT/BKN CLDS ARND 3-3.5K WILL MOVE ACROSS MSP AIRPORT DURING
THE AFTN...BUT WILL CONTINUE WITH VFR CIGS OF 4-5K AT THIS TIME.
WNDS CURRENTLY FROM THE SW...BUT IT SHOULD CHG DURING THE AFTN AS
MIXING DEVELOPS AND ALLOWS FOR SOME GUSTS UP TO 22 KTS FROM THE
WNW. WNDS WILL DECREASE TOWARD SUNSET...THEN BECOME MORE WSW/SW BY
MORNING...BUT REMAIN UNDER 8 KTS.
OUTLOOK FOR SATURDAY STILL LOOKS FAVORABLE FOR MVFR/IFR CIGS/VSBYS
AS A STORM SYSTEM MOVES FROM THE CENTRAL PLAINS/INTO THE UPPER
MIDWEST. TIMING AND TRANSITION FROM RA TO SN WILL REMAIN PROBLEMATIC
/MAINLY SOUTH OF RWF TO MSP AND RNH/...BUT CURRENT TRENDS INDICATE
THAT THE WORSE CONDITIONS WILL BE FROM 18Z/19...TO 06Z/20. OR LATE
SATURDAY AFTN...THRU THE EVENING. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/JLT
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
610 AM CST WED NOV 16 2011
.UPDATE...
UPDATED FOR THE 12Z AVIATION DISCUSSION BELOW.
.DISCUSSION...
A COLD WEST-NORTHWEST FLOW OF AIR WILL COVER THE REGION INTO
THURSDAY. A SHORT WAVE OVER NORTH DAKOTA WILL PROGRESS TO THE
WESTERN GREAT LAKES BY TONIGHT. SOME CLOUDINESS OVER CENTRAL
MN AND WEST CENTRAL WI EARLY THIS MORNING WILL PART FOR A TIME
BEFORE ANOTHER SURGE OF LOW CLOUDINESS ARRIVES FOR THE AFTERNOON
AND EVENING HOURS. OUR LOCAL MODEL AND THE RUC PAINT SOME LIGHT
ECHOES ACROSS CENTRAL MN AND WEST CENTRAL WI DURING THE AFTERNOON
AND EVENING HOURS...SO KEPT THE MENTION OF FLURRIES TO THESE
AREAS. THERE SHOULD BE A GOOD DEAL OF SUNSHINE ACROSS SOUTHERN MN
TODAY. THE MIX-DOWN TD TOOL POINTS TO DEW POINT LOWERING TO AROUND
5 DEG C DURING THE AFTERNOON. WE ARE CURRENTLY SEEING SOME SINGLE
DIGIT DEW POINTS NEAR THE SD/NE EARLY THIS MORNING. THE ARW/NMM
WRFS ALSO INDICATE DINGLE DIGIT DEW POINT IN THE SOUTH THIS
AFTERNOON. HENCE...BLENDED IN THE MIX DOWN DPS WITH CONSENSUS FOR
THE AFTERNOON AND EVENING HOURS. TRENDED A FEW DEGREES HIGHER ON
HIGH TEMPERATURES TODAY OVER THE SOUTHERN HALF OF THE CWA VERSUS
MET/MAV MOS DUE TO MORE SUNSHINE AND WHAT THE MIX DOWN MAX T WAS
SHOWING.
FLURRIES/CLOUDS WILL DIMINISH TONIGHT OVER THE NORTHERN AND
EASTERN CWA AS HIGH PRESSURE MOVES IN LATE IN THE NIGHT. THE RIDGE
WILL MOVE ACROSS THE CWA ON THURSDAY WITH FLOW BECOMING MORE
SOUTHERLY. IT WILL STILL BE A COOL DAY WITH HIGHS ONLY IN THE 30S.
AS THE RIDGE MOVES EAST THURSDAY NIGHT...A WARM FRONT WILL DEVELOP
AND MOVE NORTHEAST ACROSS THE CWA. ONLY SOME CLOUDS EXPECTED WITH
THE WARM FRONT. THIS WILL LEAD TO A WARMER FRIDAY WITH HIGHS
REACHING WELL INTO THE 40S IN MOST AREAS WITH SOME 50S IN THE
SOUTH.
THE LOW PRESSURE SYSTEM AND PRECIPITATION EVENT FOR SATURDAY AND
SATURDAY NIGHT REMAINS ON TRACK. THE GEM AND ECMWF ARE IN STEP
WITH THIS SYSTEM WHILE THE GFS LAGS BY ABOUT 6 HOURS. THE GFS
ENSEMBLE IS EVEN SLOWER BY ABOUT ANOTHER 6 HOURS. STILL EXPECT A
LOW TO TRACK FROM EASTERN NEBRASKA SATURDAY MORNING TO EASTERN WI
BY SATURDAY NIGHT. ALL SOLUTIONS INDICATE THE LOW SLOWLY FILLING
DURING THIS PERIOD WHICH IS NOTE GOOD FOR A HEAVY SNOW EVENT. WE
ALSO CONTINUE TO SEE AN OPEN WAVE ALOFT WHICH SPEAKS FOR THE
QUICKNESS WITH THIS SYSTEM. LOOKING AT SOME OF THE MID/UPPER LEVEL
FEATURES SHOWS THE H5 HEIGHT FALL TRACK FROM YELLOW MEDICINE COUNTY
TO BURNETT COUNTY. THE -15 DEG C OMEGA IS ON THE LEFT SIDE OF THIS
TRACK WITH THE DEPTH OF THE DENDRITIC GROWTH ZONE BEING ABOUT
1100M. THE WARM POCKET AT H2 ALSO TRACKS ALONG THE AFOREMENTIONED
AXIS WITH 10 DEG OF WARMING NOTED.
THE 295K THETA SURFACE PLACES 700 MB ABOUT IN THIS GENERAL AREA AS
WELL WITH PLENTY OF SATURATION AND ADIABATIC OMEGA NOTED TO THE
NORTH AND WEST. THE MIX RATIO CONTINUES TO RUN BETWEEN 2 AND 3
G/KG AND IS ALIGNED WITH THE -FN VECTOR DIVERGENCE. THIS ALL POINTS
TO A BAND OF 4 TO LOCALLY 6 INCHES FROM WEST CENTRAL MN ON
NORTHEAST TO DULUTH AND HAYWARD. THE CARIBOU SNOW TOOL USING THE GFS
AGREES PRETTY WELL WITH THIS SCENARIO. ALSO INTERESTING IS THE
16/00Z CIPS DATA...BASED ON THE TOP 15 ANALOGS...WHICH SHOWS MEAN
SNOWFALL OF 4 TO 6 FROM WEST CENTRAL MN THROUGH THE ARROWHEAD AND
FAR NORTHERN AREAS OF WI WITH 2 TO 3 INCHES FROM SOUTHWEST MN
THROUGH THE METRO AND ACROSS MUCH OF WEST CENTRAL WI.
IN THE WAKE OF THE LOW PRESSURE SYSTEM...A RATHER SUBSTANTIAL HIGH
WILL BUILD OVER THE REGION FROM SUNDAY THROUGH TUESDAY WITH DRY
WEATHER AND BELOW NORMAL TEMPERATURES OCCURRING.
&&
.AVIATION.../12Z TAF ISSUANCE/
CURRENT 3000-4500FT CEILINGS BEING OBSERVED THIS MORNING IN
PORTIONS OF NORTHERN WISCONSIN AND CENTRAL WILL LARGEST SLIDE EAST
WITH TIME AND BYPASS MOST OF THE TAF SITES. A SECOND WEAKER WAVE
WILL PASS THROUGH THE AREA TODAY AND COULD SHAKE OUT A FEW SNOW
FLURRIES AS WELL. LIKE THE PAST COUPLE DAYS...THE WIND WILL REMAIN
QUITE STRONG OUT OF THE WEST/NORTHWEST AND FINALLY BEGIN TO SUBSIDE
THIS EVENING.
KMSP...VERY LITTLE RISK FOR ANY WEATHER IMPACTS TO AVIATION
OUTSIDE THE WIND...WHICH WILL AGAIN BE QUITE GUSTY BY THIS
AFTERNOON. SUSTAINED WINDS NEAR 15KTS WITH GUSTS TO 25KTS ARE
EXPECTED ACROSS EASTERN MN. SHOULD SEE MORE SUN THAN CLOUD TODAY
AND THE WINDS WILL FINALLY RELAX THIS EVENING AND REMAIN LIGHT
THROUGH THURSDAY MORNING.
OUTLOOK...FAIRLY QUIET WEATHER OVER THE NEXT COUPLE DAYS. CEILING
AND VISIBILITY RESTRICTIONS ARE EXPECTED SATURDAY NIGHT WHEN A
SYSTEM BRINGS ACCUMULATING SNOW TO MN/WI.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
347 AM CST WED NOV 16 2011
.DISCUSSION...
A COLD WEST-NORTHWEST FLOW OF AIR WILL COVER THE REGION INTO
THURSDAY. A SHORT WAVE OVER NORTH DAKOTA WILL PROGRESS TO THE
WESTERN GREAT LAKES BY TONIGHT. SOME CLOUDINESS OVER CENTRAL
MN AND WEST CENTRAL WI EARLY THIS MORNING WILL PART FOR A TIME
BEFORE ANOTHER SURGE OF LOW CLOUDINESS ARRIVES FOR THE AFTERNOON
AND EVENING HOURS. OUR LOCAL MODEL AND THE RUC PAINT SOME LIGHT
ECHOES ACROSS CENTRAL MN AND WEST CENTRAL WI DURING THE AFTERNOON
AND EVENING HOURS...SO KEPT THE MENTION OF FLURRIES TO THESE
AREAS. THERE SHOULD BE A GOOD DEAL OF SUNSHINE ACROSS SOUTHERN MN
TODAY. THE MIX-DOWN TD TOOL POINTS TO DEW POINT LOWERING TO AROUND
5 DEG C DURING THE AFTERNOON. WE ARE CURRENTLY SEEING SOME SINGLE
DIGIT DEW POINTS NEAR THE SD/NE EARLY THIS MORNING. THE ARW/NMM
WRFS ALSO INDICATE DINGLE DIGIT DEW POINT IN THE SOUTH THIS
AFTERNOON. HENCE...BLENDED IN THE MIX DOWN DPS WITH CONSENSUS FOR
THE AFTERNOON AND EVENING HOURS. TRENDED A FEW DEGREES HIGHER ON
HIGH TEMPERATURES TODAY OVER THE SOUTHERN HALF OF THE CWA VERSUS
MET/MAV MOS DUE TO MORE SUNSHINE AND WHAT THE MIX DOWN MAX T WAS
SHOWING.
FLURRIES/CLOUDS WILL DIMINISH TONIGHT OVER THE NORTHERN AND
EASTERN CWA AS HIGH PRESSURE MOVES IN LATE IN THE NIGHT. THE RIDGE
WILL MOVE ACROSS THE CWA ON THURSDAY WITH FLOW BECOMING MORE
SOUTHERLY. IT WILL STILL BE A COOL DAY WITH HIGHS ONLY IN THE 30S.
AS THE RIDGE MOVES EAST THURSDAY NIGHT...A WARM FRONT WILL DEVELOP
AND MOVE NORTHEAST ACROSS THE CWA. ONLY SOME CLOUDS EXPECTED WITH
THE WARM FRONT. THIS WILL LEAD TO A WARMER FRIDAY WITH HIGHS
REACHING WELL INTO THE 40S IN MOST AREAS WITH SOME 50S IN THE
SOUTH.
THE LOW PRESSURE SYSTEM AND PRECIPITATION EVENT FOR SATURDAY AND
SATURDAY NIGHT REMAINS ON TRACK. THE GEM AND ECMWF ARE IN STEP
WITH THIS SYSTEM WHILE THE GFS LAGS BY ABOUT 6 HOURS. THE GFS
ENSEMBLE IS EVEN SLOWER BY ABOUT ANOTHER 6 HOURS. STILL EXPECT A
LOW TO TRACK FROM EASTERN NEBRASKA SATURDAY MORNING TO EASTERN WI
BY SATURDAY NIGHT. ALL SOLUTIONS INDICATE THE LOW SLOWLY FILLING
DURING THIS PERIOD WHICH IS NOTE GOOD FOR A HEAVY SNOW EVENT. WE
ALSO CONTINUE TO SEE AN OPEN WAVE ALOFT WHICH SPEAKS FOR THE
QUICKNESS WITH THIS SYSTEM. LOOKING AT SOME OF THE MID/UPPER LEVEL
FEATURES SHOWS THE H5 HEIGHT FALL TRACK FROM YELLOW MEDICINE COUNTY
TO BURNETT COUNTY. THE -15 DEG C OMEGA IS ON THE LEFT SIDE OF THIS
TRACK WITH THE DEPTH OF THE DENDRITIC GROWTH ZONE BEING ABOUT
1100M. THE WARM POCKET AT H2 ALSO TRACKS ALONG THE AFOREMENTIONED
AXIS WITH 10 DEG OF WARMING NOTED.
THE 295K THETA SURFACE PLACES 700 MB ABOUT IN THIS GENERAL AREA AS
WELL WITH PLENTY OF SATURATION AND ADIABATIC OMEGA NOTED TO THE
NORTH AND WEST. THE MIX RATIO CONTINUES TO RUN BETWEEN 2 AND 3
G/KG AND IS ALIGNED WITH THE -FN VECTOR DIVERGENCE. THIS ALL POINTS
TO A BAND OF 4 TO LOCALLY 6 INCHES FROM WEST CENTRAL MN ON
NORTHEAST TO DULUTH AND HAYWARD. THE CARIBOU SNOW TOOL USING THE GFS
AGREES PRETTY WELL WITH THIS SCENARIO. ALSO INTERESTING IS THE
16/00Z CIPS DATA...BASED ON THE TOP 15 ANALOGS...WHICH SHOWS MEAN
SNOWFALL OF 4 TO 6 FROM WEST CENTRAL MN THROUGH THE ARROWHEAD AND
FAR NORTHERN AREAS OF WI WITH 2 TO 3 INCHES FROM SOUTHWEST MN
THROUGH THE METRO AND ACROSS MUCH OF WEST CENTRAL WI.
IN THE WAKE OF THE LOW PRESSURE SYSTEM...A RATHER SUBSTANTIAL HIGH
WILL BUILD OVER THE REGION FROM SUNDAY THROUGH TUESDAY WITH DRY
WEATHER AND BELOW NORMAL TEMPERATURES OCCURRING.
&&
.AVIATION... /06Z TAF ISSUANCE/
BKN040 WILL AFFECT MOST TAFS BUT RWF FOR A TIME DURING THE NEXT 4-6
HOURS AS NW FLOW BRINGS DOWN CLOUDS IN WAKE OF STRONG VORT NOW VCNTY
OF DULUTH. UPSTREAM VORT IN SASK WILL MOVE ACROSS N MN ON WEDNESDAY
SENDING ANOTHER CDFNT ACROSS AREA WITH MORE VFR CLDS. GRADIENT
REMAINS FAIRLY STRONG OVERNITE...SO WINDS SHUD REMAIN IN 12 TO 15 KT
RANGE. WNW WINDS BECOMING GUSTY AGAIN DURING THE DAY WED WITH GUSTS
20 TO 25 KTS BY AROUND 18Z.
KMSP...SHUD SEE A PERIOD OF BKN040 BETWEEN 06Z-10Z AS CLOUDS SKIRT
ACROSS CENTRAL MN. GUSTINESS HAS SLOWLY BEEN DIMINISHING LAST
COUPLE OF HOURS AND THIS TREND WILL CONTINUE OVERNITE...SUSTAINED
WINDS SHUD REMAIN IN THE 12-15 KT RANGE MOST OF NITE. GUSTS 20-25
KT RETURNING BY 18Z WED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/BAP
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
333 AM CST WED NOV 16 2011
.DISCUSSION...
A COLD WEST-NORTHWEST FLOW OF AIR WILL COVER THE REGION INTO
THURSDAY. A SHORT WAVE OVER NORTH DAKOTA WILL PROGRESS TO THE
WESTERN GREAT LAKES BY TONIGHT. SOME CLOUDINESS OVER CENTRAL
MN AND WEST CENTRAL WI EARLY THIS MORNING WILL PART FOR A TIME
BEFORE ANOTHER SURGE OF LOW CLOUDINESS ARRIVES FOR THE AFTERNOON
AND EVENING HOURS. OUR LOCAL MODEL AND THE RUC PAINT SOME LIGHT
ECHOES ACROSS CENTRAL MN AND WEST CENTRAL WI DURING THE AFTERNOON
AND EVENING HOURS...SO KEPT THE MENTION OF FLURRIES TO THESE
AREAS. THERE SHOULD BE A GOOD DEAL OF SUNSHINE ACROSS SOUTHERN MN
TODAY. THE MIX-DOWN TD TOOL POINTS TO DEW POINT LOWERING TO AROUND
5 DEG C DURING THE AFTERNOON. WE ARE CURRENTLY SEEING SOME SINGLE
DIGIT DEW POINTS NEAR THE SD/NE EARLY THIS MORNING. THE ARW/NMM
WRFS ALSO INDICATE DINGLE DIGIT DEW POINT IN THE SOUTH THIS
AFTERNOON. HENCE...BLENDED IN THE MIX DOWN DPS WITH CONSENSUS FOR
THE AFTERNOON AND EVENING HOURS. TRENDED A FEW DEGREES HIGHER ON
HIGH TEMPERATURES TODAY OVER THE SOUTHERN HALF OF THE CWA VERSUS
MET/MAV MOS DUE TO MORE SUNSHINE AND WHAT THE MIX DOWN MAX T WAS
SHOWING.
FLURRIES/CLOUDS WILL DIMINISH TONIGHT OVER THE NORTHERN AND
EASTERN CWA AS HIGH PRESSURE MOVES IN LATE IN THE NIGHT. THE RIDGE
WILL MOVE ACROSS THE CWA ON THURSDAY WITH FLOW BECOMING MORE
SOUTHERLY. IT WILL STILL BE A COOL DAY WITH HIGHS ONLY IN THE 30S.
AS THE RIDGE MOVES EAST THURSDAY NIGHT...A WARM FRONT WILL DEVELOP
AND MOVE NORTHEAST ACROSS THE CWA. ONLY SOME CLOUDS EXPECTED WITH
THE WARM FRONT. THIS WILL LEAD TO A WARMER FRIDAY WITH HIGHS
REACHING WELL INTO THE 40S IN MOST AREAS WITH SOME 50S IN THE
SOUTH.
THE LOW PRESSURE SYSTEM AND PRECIPITATION EVENT FOR SATURDAY AND
SATURDAY NIGHT REMAINS ON TRACK. THE GEM AND ECMWF ARE IN STEP
WITH THIS SYSTEM WHILE THE GFS LAGS BY ABOUT 6 HOURS. THE GFS
ENSEMBLE IS EVEN SLOWER BY ABOUT ANOTHER 6 HOURS. STILL EXPECT A
LOW TO TRACK FROM EASTERN NEBRASKA SATURDAY MORNING TO EASTERN WI
BY SATURDAY NIGHT. ALL SOLUTIONS INDICATE THE LOW SLOWLY FILLING
DURING THIS PERIOD WHICH IS NOTE GOOD FOR A HEAVY SNOW EVENT. WE
ALSO CONTINUE TO SEE AN OPEN WAVE ALOFT WHICH SPEAKS FOR THE
QUICKNESS WITH THIS SYSTEM. LOOKING AT SOME OF THE MID/UPPER LEVEL
FEATURES SHOWS THE H5 HEIGHT FALL TRACK FROM YELLOW MEDICINE COUNTY
TO BURNETT COUNTY. THE -15 DEG C OMEGA IS ON THE LEFT SIDE OF THIS
TRACK WITH THE DEPTH OF THE DENDRITIC GROWTH ZONE BEING ABOUT
1100M. THE WARM POCKET AT H2 ALSO TRACKS ALONG THE AFOREMENTIONED
AXIS WITH 10 DEG OF WARMING NOTED.
THE 295K THETA SURFACE PLACES 700 MB ABOUT IN THIS GENERAL AREA AS
WELL WITH PLENTY OF SATURATION AND ADIABATIC OMEGA NOTED TO THE
NORTH AND WEST. THE MIX RATIO CONTINUES TO RUN BETWEEN 2 AND 3
G/KG AND IS ALIGNED WITH THE -FN VECTOR DIVERGENCE. THIS ALL POINTS
TO A BAND OF 4 TO LOCALLY 6 INCHES FROM WEST CENTRAL MN ON
NORTHEAST TO DULUTH AND HAYWARD. THE CARIBOU SNOW TOOL USING THE GFS
AGREES WITH THIS SCENARIO. SNOW AMOUNTS TO THE SOUTHEAST OF THIS
AREA WILL BE MORE IN THE 1 TO 3 INCH RANGE AS IT CURRENTLY STANDS.
THE SMALLER TOTALS WOULD BE FROM ALBERT LEA TO EAU CLAIRE WHERE
RAIN WILL DOMINATE FOR MUCH OF THE PERIOD.
A RATHER SUBSTANTIAL HIGH PRESSURE SYSTEM WILL BUILD OVER THE
REGION FROM SUNDAY THROUGH TUESDAY WITH DRY WEATHER AND BELOW
NORMAL TEMPERATURES OCCURRING.
&&
.AVIATION... /06Z TAF ISSUANCE/
BKN040 WILL AFFECT MOST TAFS BUT RWF FOR A TIME DURING THE NEXT 4-6
HOURS AS NW FLOW BRINGS DOWN CLOUDS IN WAKE OF STRONG VORT NOW VCNTY
OF DULUTH. UPSTREAM VORT IN SASK WILL MOVE ACROSS N MN ON WEDNESDAY
SENDING ANOTHER CDFNT ACROSS AREA WITH MORE VFR CLDS. GRADIENT
REMAINS FAIRLY STRONG OVERNITE...SO WINDS SHUD REMAIN IN 12 TO 15 KT
RANGE. WNW WINDS BECOMING GUSTY AGAIN DURING THE DAY WED WITH GUSTS
20 TO 25 KTS BY AROUND 18Z.
KMSP...SHUD SEE A PERIOD OF BKN040 BETWEEN 06Z-10Z AS CLOUDS SKIRT
ACROSS CENTRAL MN. GUSTINESS HAS SLOWLY BEEN DIMINISHING LAST
COUPLE OF HOURS AND THIS TREND WILL CONTINUE OVERNITE...SUSTAINED
WINDS SHUD REMAIN IN THE 12-15 KT RANGE MOST OF NITE. GUSTS 20-25
KT RETURNING BY 18Z WED.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/BAP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
318 PM EST WED NOV 16 2011
.SYNOPSIS...
A COLD FRONT OVER THE TENNESSEE VALLEY WILL SLIDE EASTWARD BRINGING
SHOWERS AND A CHANCE OF THUNDERSTORMS...INCLUDING SEVERE
WEATHER...TONIGHT THROUGH THURSDAY MORNING. MUCH COOLER AND DRIER
AIR WILL FOLLOW LATE THURSDAY AND FRIDAY. HIGH PRESSURE WILL MOVE
OVERHEAD WITH TEMPERATURES MODERATING DURING THE WEEKEND. A SECOND
FRONT WILL DROP SOUTH THROUGH THE AREA TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 300 PM WEDNESDAY...TROPICAL WARMTH AND HUMIDITY WILL COME TO A
CRASHING HALT LATE TONIGHT AS A STRONG COLD FRONT ARRIVES FROM THE
WEST. THE TRANSITION FROM A TROPICAL TO AN ARCTIC AIRMASS WILL NOT
BE AN EASY ONE...AND SEVERE THUNDERSTORMS APPEAR POSSIBLE ACROSS THE
EASTERN CAROLINAS TONIGHT.
INSTABILITY PARAMETERS ARE IMPRESSIVE FOR A COOL-SEASON EVENT.
ALTHOUGH SURFACE CAPE FALLS AWAY TO A FEW HUNDRED J/KG AFTER DARK
WITH 75-100 J/KG OF INHIBITION TO OVERCOME...STARTING TO LIFT A
PARCEL FROM AROUND 925 MB YIELDS 600-1500 J/KG OF UNINHIBITED CAPE
AIDED BY REASONABLY STEEP MID AND UPPER LEVEL LAPSE RATES. UNLIKE
OUR TYPICAL WINTERTIME "SEVERE SHOWER" SCENARIOS THERE COULD
ACTUALLY BE DEEP (40+ KFT) CONVECTION TONIGHT. WIND SHEAR PARAMETERS
ARE ALSO IMPRESSIVE: 50-60 KT OF 0-6 KM BULK SHEAR...200-300 M^2/S^2
0-3 KM HELICITY...AND 50 KT WIND SPEEDS WITHIN 2500 FEET OF THE
GROUND ALL POINT TOWARD ORGANIZED STORMS...PERHAPS EVEN
SUPERCELLS...WITH THE POTENTIAL FOR WIND DAMAGE AND TORNADOES.
SYNOPTICALLY A 300 MB JET STREAK WILL MOVE EAST THROUGH THE
MID-ATLANTIC STATES TONIGHT. THIS WILL PLACE THE EASTERN CAROLINAS
WITHIN THE RIGHT-ENTRANCE REGION OF THE JET STREAK AIDING IN
DEEP-LAYER LIFT. TIMING-WISE...THE LAST THREE RUNS (15-16-17Z) OF
THE HRRR RAPID UPDATE MODEL ALL PLACE THE LEADING EDGE OF THE SQUALL
LINE IN WESTERN DARLINGTON COUNTY AT 7 PM...MOVING INTO FLORENCE...
DILLON AND LUMBERTON BY 8 PM...AND TO THE COAST BETWEEN 10 PM AND
MIDNIGHT. OUR HIGHEST POPS (80-90%) EXTEND FROM FLORENCE...MARION
AND MYRTLE BEACH NORTHWARD THROUGH SOUTHEASTERN NORTH CAROLINA.
LOWER POPS (50-60%) ARE FORECAST SOUTH INTO THE GEORGETOWN AREA
WHERE THIS FIRST BATCH OF CONVECTION MAY BE TOO FAR NORTH FOR
IMPACTS. ADDITIONAL SHOWERS AND POSSIBLY THUNDERSTORMS MAY DEVELOP
BEHIND THIS FIRST BATCH...ASSOCIATED WITH SUBTLE UPPER DISTURBANCES
WORKING ON RESIDUAL ELEVATED INSTABILITY. THIS SECOND BATCH OF
CONVECTIVE ACTIVITY COULD CONTINUE UP UNTIL THE TIME OF THE FRONTAL
PASSAGE AROUND DAYBREAK THURSDAY.
LOW TEMPERATURES TONIGHT WILL BE TRICKY WITH THE SURFACE COLD FRONT
LIKELY ARRIVING AROUND 12Z. WE ARE FORECASTING MID 60S ON THE COAST
AND 59-63 INLAND...HOWEVER THERE IS SIGNIFICANT BUST POTENTIAL IN
EITHER DIRECTION IF THE FRONT IS ONLY A COUPLE HOURS FASTER OR SLOWER
THAN IS CURRENTLY FORECAST.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...CONCERN DURING THE PERIOD REVOLVES AROUND
COLD FRONTAL PASSAGE AND ASSOCIATED CONVECTION EARLY
THURSDAY...FOLLOWED BY A DRASTIC DROP IN TEMPERATURES WHICH WILL
MAKE IT FEEL ONCE AGAIN LIKE EARLY WINTER.
STRONG COLD FRONT WILL BE JUST INSIDE WESTERN EDGE OF THE CWA
THURSDAY MORNING AND RAPIDLY MOVING EAST. THE UNCERTAINTY WITH
STRENGTH OF CONVECTION REVOLVES AROUND THE FACT THAT FROPA IS
OCCURRING AT A NON-IDEAL TIME WITH RESPECT TO INSTABILITY.
HOWEVER...PARAMETERS DO SUGGEST THAT CONVECTION WILL BE ONGOING AT
THE BEGINNING OF THE PERIOD...ESPECIALLY ACROSS THE EASTERN ZONES.
RIDGE OF LOW LEVEL THETA-E AIR REMAINS IN PLACE THROUGH THURSDAY
MORNING ALONG WITH STEEP MID LEVEL LAPSE RATES AND PWATS NEAR 1.5
INCHES. ADDITIONALLY...SOME PVA NEAR A VORT LOBE TRAILING THROUGH
THE EASTERN CAROLINAS...LOCALLY ENHANCED DIFFLUENCE IN THE RIGHT
ENTRANCE REGION OF AN EXITING UPPER JET...AND THE COLD FRONT ITSELF
WILL HELP FORCE SOME LIFT AND KEEP CONVECTION GOING THROUGH LATE
MORNING. 12 HOUR SREF PRECIP PROBS DO NOT DROP BELOW 50 PERCENT
UNTIL AFTER 03Z FRIDAY...SO ALTHOUGH THE SEVERE THREAT AFTER SUNRISE
THURSDAY APPEARS LIMITED WILL KEEP TSTM MENTION THROUGH LATE MORNING
ALONG THE COAST...WITH SOME LIGHT RAIN POSSIBLE UNTIL EARLY AFTN.
FROPA OCCURS ACROSS THE ENTIRE CWA BY THE AFTN BRINGING AN END TO
PRECIP THROUGH THE REMAINDER OF THE SHORT TERM. DRYING WILL OCCUR
BEHIND FRONT AS HIGH PRESSURE BUILDS INTO THE REGION...BUT POST
FRONTAL CLOUD COVER/STRATUS WILL EXIST THROUGH MUCH OF THURSDAY
BEFORE CLEARING ON FRIDAY.
THE HIGHEST TEMPS OF THE PERIOD WILL OCCUR THURSDAY MORNING ALONG
AND AHEAD OF THE FRONT...DROPPING RAPIDLY IN THE AFTN AS STRONG CAA
DEVELOPS. LARGE BUST POTENTIAL ON MAX TEMPS THURSDAY DEPENDING ON
EXACT TIMING OF FROPA...BUT EXPECT TEMPS AROUND 60 INLAND...MID 60S
AT THE COAST AT DAYBREAK THURSDAY...THEN FALLING THROUGH THE DAY.
MEX/MAV IN AGREEMENT WITH MAX TEMPS FRIDAY IN THE MID 50S...BUT
GUIDANCE HAS A TENDENCY TO OVER FORECAST HIGHS THE DAY AFTER A STRONG
FROPA. WILL TREND MAXES DOWN TO THE LOW/MID 50S...BUT NOTE THIS MAY
STILL BE TOO WARM. MINS EACH NIGHT WILL BE IN THE MID 30S AT THE
COAST...AROUND 30 IN THE COLDER SPOTS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...WEAK RIDGING ALOFT WILL BECOME SUPPRESSED LATE
IN THE PERIOD AS 5H FLOW BECOMES MORE ZONAL. MUCH OF THE PERIOD WILL
BE DOMINATED BY ELONGATED SURFACE HIGH WITH A WEAK COASTAL TROF
DEVELOPING SAT INTO SUN. COASTAL TROF LOOKS PRETTY WEAK SO DO NOT
THINK PRECIP WILL NOT BE AN ISSUE. BACKDOOR COLD FRONT STALLED NORTH
OF THE AREA MON WILL PUSH SOUTH ACROSS THE AREA TUE. NOT MUCH
FORCING ALONG THE FRONT AS IT HEADS SOUTH. FROPA WILL BE MARKED BY
AIR MASS CHANGE BUT VERY LITTLE IF ANY PRECIP. WEAK ISENTROPIC LIFT
LATE IN THE PERIOD AS MID LEVEL RIDGE SHIFTS EAST WILL PROVIDE THE
BEST CHANCE FOR PRECIP DURING THE PERIOD. HOWEVER...GIVEN THE
UNCERTAINTY WITH RESPECT TO THE EVENT PLAN TO CARRY SILENT POP FOR
NOW. TEMPERATURES WILL START OUT NEAR CLIMO SAT BUT END UP ABOVE
CLIMO SAT NIGHT AND FOR THE REST OF THE PERIOD. HIGHS WILL RUN 5 TO
8 DEGREES ABOVE CLIMO WITH LOWS CLOSER TO 10 DEGREES ABOVE.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 17Z...A LARGE PORTION OF THE CWA HAS SCATTERED OUT...HOWEVER
EXPECT AN MVFR CEILING TO RE-EMERGE AS CU SPREADS OUT INTO A CEILING
DUE TO A PERSISTENT SUBSIDENCE INVERSION. GUSTY SOUTHWEST WINDS WILL
CONTINUE THROUGH THE AFTERNOON HOURS. THIS EVENING...EXPECT IFR
CEILINGS TO COME BACK...AS LOW LEVEL MOISTURE GETS TRAPPED.
CONVECTION AHEAD OF A FRONTAL BOUNDARY WILL AFFECT THE WESTERN
TERMINALS BEFORE MIDNIGHT...WITH THE PRE-FRONTAL TROUGH WITH
MODERATE OMEGA REACHING THE COAST BY 07-08Z. LOOK FOR INTERMITTENT
IFR VISIBILITIES IN THE HEAVY SHOWERS WITH SOME INCREASE IN WINDS.
THE FIRST SET OF CONVECTION WILL MOVE OFFSHORE BEFORE
DAYBREAK...MEANWHILE MORE CONVECTION ASSOCIATED WITH THE FRONT WILL
MOVE THROUGH THE CWA DURING THE DAY...AGAIN WITH INTERMITTENT HEAVY
RAIN WITH MODERATE FRONTAL LIFT. WINDS WILL SHIFT TO THE NORTH AND
GUSTY BEHIND THE FRONT. MODELS INDICATE LOW CEILINGS WILL REMAIN
BEHIND THE FRONT...BUT WOULD NOT BE SURPRISE TO SEE VFR CONDITIONS
BY THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...EXPECT VFR FRIDAY AND SATURDAY...WITH LOWERED
CONFIDENCE FOR POTENTIAL IFR FOG/STRATUS SUNDAY AND MONDAY MORNINGS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...TROPICAL MOISTURE MOVING ACROSS CHILLY
NEARSHORE OCEAN WATERS HAS RESULTED IN AREAS OF DENSE SEA FOG TODAY.
THIS SHOULD CONTINUE INTO THE EVENING HOURS WITH VISIBILITIES LESS
THAN ONE MILE AT TIMES. THE WORST VISIBILITIES ARE EXPECTED ACROSS
THE WATERS WITHIN 5-8 MILES OF SHORE WHERE WATER TEMPERATURES AND
AIR TEMPERATURES ARE COOLEST.
OTHERWISE...SOUTHWEST WINDS WILL RAMP UP OVERNIGHT IN ADVANCE OF A
STRONG COLD FRONT MOVING EAST TOWARD THE CAROLINAS. LATEST HIGH-
RESOLUTION MODELS SUGGEST THE FIRST BATCH OF SHOWERS AND STRONG
THUNDERSTORMS COULD REACH THE COASTLINE AROUND 10 PM THIS EVENING...
WITH ADDITIONAL SHOWERS AND STORMS POSSIBLE OVERNIGHT UP UNTIL THE
ACTUAL SURFACE COLD FRONT ARRIVES AFTER DAYBREAK THURSDAY MORNING.
SEAS SHOULD GRADUALLY BUILD TONIGHT WITH THE STRONGER SOUTHWEST
WINDS ARRIVING AHEAD OF THE FRONT...REACHING AS HIGH AS 6-8 FT NEAR
CAPE FEAR LATE TONIGHT. THE STRONGEST WINDS SHOULD REMAIN OUT BEYOND
20 MILES FROM SHORE WHERE WARMER AIR AND WATER TEMPERATURES WILL
SUPPORT DEEPER MIXING...BRINGING THESE WINDS DOWN TO THE OCEAN
SURFACE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...PERIOD BEGINS WITH SOLID SCA CONDITIONS
ACROSS THE COASTAL WATERS AS PINCHED GRADIENT EXISTS AHEAD OF A COLD
FRONT. WINDS THURSDAY WILL QUICKLY VEER FROM SW IN THE MORNING TO
NORTHERLY DURING THE AFTN BEHIND THE COLD FRONT. SPEEDS WILL
INCREASE AS WELL...BECOMING SUSTAINED AT NEARLY 25 KTS UNTIL
THURSDAY NIGHT...HELPING TO GENERATE SEAS OF 5-7 FT. CHALLENGE THEN
BECOMES DETERMINING EXACTLY WHEN CONDITIONS WILL DROP BELOW SCA
THRESHOLDS. ALTHOUGH GRADIENT WILL REMAIN PINCHED AS HIGH PRESSURE
SLIDES TOWARDS THE AREA...EXPECT IT WILL SLACKEN ENOUGH TO DROP
WINDS TO 15-20 KTS AND SEAS TO 4-5 FT BY FRIDAY MORNING...SO HAVE
LEFT CURRENT SCA AS-IS. WINDS VEER TO THE NE FRIDAY NIGHT AND EASE
FURTHER...REDUCING SEAS TO 2-4 FT BY THE END OF THE PERIOD.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 PM WEDNESDAY...LIGHT NORTHEAST FLOW WILL BE QUICK TO VEER TO
SOUTHEASTERLY AS WEAK COASTAL TROUGH DEVELOPS. REMAINS OF THE
TROUGH PUSH INLAND SAT NIGHT INTO SUN AND HIGH PRESSURE RETURNS.
WEAK GRADIENT WILL REMAIN IN PLACE THROUGH THE END OF THE PERIOD
WITH SOUTH TO SOUTHWEST FLOW AROUND 10 KT. COLD FRONT MAY DROP IN
FROM THE NORTH AT THE END OF THE PERIOD...THOUGH TIMING IS STILL IN
QUESTION. SEAS WILL RUN 2 TO 4 FT SAT DROPPING TO 2 TO 3 FT SUN
AND MON.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST THURSDAY NIGHT FOR
AMZ250-252-254-256.
&&
$$
SYNOPSIS...TRA/JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...III
AVIATION...DL
MARINE...ALL
AREA FORECAST DISCUSSION...CORRECTED
NWS WILMINGTON NC
1149 AM EST WED NOV 16 2011
.SYNOPSIS...
A COLD FRONT OVER THE TENNESSEE VALLEY WILL SLIDE EASTWARD BRINGING
SHOWERS AND A CHANCE OF THUNDERSTORMS...INCLUDING SEVERE
WEATHER...TONIGHT INTO THROUGH THURSDAY MORNING. MUCH COOLER AND
DRIER AIR WILL FOLLOW LATE THURSDAY AND FRIDAY. HIGH PRESSURE WILL
MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING THE WEEKEND.
ANOTHER FRONT WILL SHIFT TOWARD THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...WARM MOIST SOUTHWEST FLOW CONTINUES OVER
THE CAROLINAS TODAY IN ADVANCE OF A STRONG COLD FRONT NOW LOCATED IN
EASTERN TENNESSEE...NORTHERN ALABAMA...AND MISSISSIPPI. TODAY SHOULD
BE THE WARMEST DAY OF THIS ENTIRE STRING OF MILD WEATHER DATING BACK
TO SUNDAY...WITH THIS AFTERNOON`S HIGHS REACHING THE LOWER 80S
INLAND AWAY FROM MARINE INFLUENCES. 850 MB TEMPS IN THE +15C TO
+16C RANGE WOULD BE MORE AT HOME IN JUNE THAN IN NOVEMBER...AND WILL
SUPPORT THESE VERY MILD READINGS. RECORD HIGHS FOR TODAY ARE IN THE
MID TO UPPER 80S AND SHOULD REMAIN UNTOUCHED.
DEWPOINTS IN THE UPPER 60S PLUS A LONG WIND FETCH ACROSS THE COLD
NEARSHORE COASTAL WATERS IS PRODUCING AREAS OF FOG AND VERY LOW
STRATUS CLOUDS OVER THE OCEAN AND SOME OF THE BEACHES. VISIBILITIES
IN THE 0.25 TO 1 MILE RANGE ARE COMMON ON THE BEACHES AND OUT OVER
THE COASTAL WATERS. AS LONG AS THE SUN IS SHINING TODAY THIS FOG
SHOULD HAVE LITTLE SUCCESS MAKING IT MORE THAN 1 MILE INLAND OR
SO...BUT ANY REMAINING FOG THIS EVENING COULD PUSH FARTHER INLAND.
FIRST WE HAVE TRIMMED BACK POPS TODAY WITH ALL SHORT-TERM GUIDANCE
SUGGESTING WE WILL SEE LITTLE IF ANY SHOWER ACTIVITY OVER OUR
FORECAST AREA BEFORE DARK. WE DID LEAVE A SMALL 20 POP WEST OF I-95
LATE THIS AFTERNOON WHERE ONE OF THE PREVIOUS THREE HRRR RUNS SHOWS
SOME SHOWERS POSSIBLE. THERE IS INSTABILITY (CAPE AROUND 1000 J/KG)
FORECAST TO DEVELOP THIS AFTERNOON BUT TRIGGERS FOR CONVECTION ARE
LARGELY ABSENT.
THE BIG STORY IS THE POTENTIAL FOR SEVERE WEATHER AHEAD OF THE FRONT
TONIGHT. ALTHOUGH SURFACE-BASED CAPE/INSTABILITY IS NOT IMPRESSIVE
AFTER SUNSET THERE IS RATHER LARGE ELEVATED CAPE WHEN PARCELS AT
950/925 MB ARE CONSIDERED. RATHER STEEP LAPSE RATES THROUGH ALL THE
MID AND UPPER LEVELS OF THE ATMOSPHERE WILL BE SUPPORTIVE OF DEEP
CONVECTION. SYNOPTIC FACTORS SUPPORTIVE OF LIFT INCLUDE A
FAVORABLY-POSITIONED JET STREAK MOVING THROUGH THE MID-ATLANTIC
REGION TONIGHT PLACING THE CAROLINAS SQUARELY IN THE FAVORED
RIGHT-ENTRANCE REGION...STRONG AND SLIGHTLY BACKED LOW LEVEL WINDS
RELATIVE TO THE MID AND UPPER LEVEL FLOW PRODUCING 0-6 KM BULK SHEAR
VALUES ON THE ORDER OF 50-70 KT...AND SEVERAL 500 MB VORTICITY
CENTERS PASSING OVER OR JUST NORTH OF OUR FORECAST AREA. THE LATEST
SPC CONVECTIVE OUTLOOK INCREASED SEVERE WEATHER PROBABILITIES FOR
WIND AND TORNADOES...AND WE WOULD NOT BE AT ALL SURPRISED TO SEE
TORNADO WATCHES FOR PORTIONS OF OUR FORECAST AREA THIS EVENING AND
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...FORECAST MODELS HAVE SLOWED DOWN THE
PROGRESSION OF THE COLD FRONT EVER SO SLIGHTLY AND HAVE THEREFORE
EXTENDED POPS ACROSS THE BOARD INTO THE LATE MORNING
HOURS...ESPECIALLY COASTAL AREAS. OTHERWISE INTERESTING
TEMPERATURE FORECAST FOR THURSDAY HIGHS AS THE MAV NUMBERS SHOW NO
WARMING IN WILMINGTON WITH LITTLE ELSEWHERE. WITH THE DOWNSLOPE
FLOW AND COLD AIR ADVECTION NOT THAT IMPRESSIVE...DID ADD A DEGREE
OR TWO TO THE MAV NUMBERS. FOR FRIDAY MORNING WINDS DECOUPLE
INLAND WHILE REMAINING UP SLIGHTLY ALONG THE COAST AND ADJUSTED
MOS NUMBERS ACCORDINGLY. COOL DAY FRIDAY WITH MOST AREAS REMAINING
BELOW 60.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...EXTENDED FORECAST IS RATHER UNEVENTFUL AS
THE PATTERN QUICKLY EVOLVES FROM ZONAL TO RIDGING ACROSS THE
SOUTHEAST...SIMILAR TO THE PATTERN WE HAVE EXPERIENCED THE PAST
FEW DAYS. HPC IS FAVORING A BLEND OF THE GFS/ECMWF AND UKMET.
REALLY THE ONLY FORECAST CHALLENGES INVOLVE LIGHT COASTAL TROUGH
QPF SATURDAY AND A BACKDOOR FRONT TUESDAY. AS FOR THE
FORMER...MAINTAINED A DRY FORECAST AS THE MODELS ARE USUALLY
OVERDONE WITH THE QPF AND IN REALITY IT IS GENERALLY A STRATUS
LAYER. REGARDING THE FRONT...THE LATEST GFS IS MORE BULLISH IN
PUSHING THE FRONT SOUTH WITH THE EFFECTS ONLY BEING AN AIRMASS
CHANGE. THE 0000 UTC ECMWF HAS BACKED OFF A FURTHER SOUTH
SOLUTION. OTHERWISE...AS WE JUST EXPERIENCED...ABOVE NORMAL TO
DOWN RIGHT BALMY CONDITIONS FOR LATE IN THE WEEKEND AND EARLY NEXT
WEEK.
&&
.AVIATION /17Z WEDNESDAY THROUGH MONDAY/...
AS OF 17Z...A LARGE PORTION OF THE CWA HAS SCATTERED OUT...HOWEVER
EXPECT AN MVFR CEILING TO RE-EMERGE AS CU SPREADS OUT INTO A CEILING
DUE TO A PERSISTENT SUBSIDENCE INVERSION. GUSTY SOUTHWEST WINDS WILL
CONTINUE THROUGH THE AFTERNOON HOURS. THIS EVENING...EXPECT IFR
CEILINGS TO COME BACK...AS LOW LEVEL MOISTURE GETS TRAPPED.
CONVECTION AHEAD OF A FRONTAL BOUNDARY WILL AFFECT THE WESTERN
TERMINALS BEFORE MIDNIGHT...WITH THE PRE-FRONTAL TROUGH WITH
MODERATE OMEGA REACHING THE COAST BY 07-08Z. LOOK FOR INTERMITTENT
IFR VISIBILITIES IN THE HEAVY SHOWERS WITH SOME INCREASE IN WINDS.
THE FIRST SET OF CONVECTION WILL MOVE OFFSHORE BEFORE
DAYBREAK...MEANWHILE MORE CONVECTION ASSOCIATED WITH THE FRONT WILL
MOVE THROUGH THE CWA DURING THE DAY...AGAIN WITH INTERMITTENT HEAVY
RAIN WITH MODERATE FRONTAL LIFT. WINDS WILL SHIFT TO THE NORTH AND
GUSTY BEHIND THE FRONT. MODELS INDICATE LOW CEILINGS WILL REMAIN
BEHIND THE FRONT...BUT WOULD NOT BE SURPRISE TO SEE VFR CONDITIONS
BY THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...EXPECT VFR FRIDAY AND SATURDAY...WITH LOWERED
CONFIDENCE FOR POTENTIAL IFR FOG/STRATUS SUNDAY AND MONDAY MORNINGS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...SATELLITE IMAGERY...SURF CAMS...AND
OBSERVATIONS FROM NORTH MYRTLE BEACH AND SOUTHPORT CONTINUE TO
INDICATE EXPANSIVE AREAS OF DENSE SEA FOG THIS MORNING. WE WILL
LIKELY HAVE TO EXTEND THE TIME OF THE DENSE FOG ADVISORY LATER THIS
MORNING AS THE MOIST SOUTHWESTERLY FLOW IS EXPECTED TO CONTINUE
THROUGH TODAY AND INTO THIS EVENING. THERE IS QUITE A THERMAL
GRADIENT ACROSS THE AREA WITH THE FRYING PAN SHOALS BUOY REPORTING
AN AIR TEMP OF 75...WHILE 66-67 DEGREE TEMPS ARE BEING REPORTED ON
THE BEACHES NEAR CAPE FEAR.
SOUTHWESTERLY WINDS AROUND 15 KT WILL INCREASE FURTHER TONIGHT AS
THE GRADIENT TIGHTENS AHEAD OF THE INCOMING STRONG COLD FRONT.
SHOWERS AND THUNDERSTORMS WILL ALSO INCREASE IN COVERAGE TONIGHT.
THE SMALL CRAFT ADVISORY REMAINS IN PLACE FOR THE ROUGHER CONDITIONS
NEAR AND AHEAD OF THE FRONT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...MAIN FORECAST CHALLENGE WILL BE WHEN TO
CONCLUDE THE SMALL CRAFT ADVISORY LATE THURSDAY EVENING. A PERIOD
OF STRONG NORTHERLY WINDS WILL FOLLOW THE FRONT THURSDAY INTO
THURSDAY EVENING. FOR NOW WITH THE TIMING STILL OUT FOUR
PERIODS...WILL NOT TWEAK BUT ISSUE THE DISCLAIMER THE HEADLINE MAY
HAVE TO BE EXTENDED A FEW HOURS. WINDS VEER TO NORTHEASTERLY
FRIDAY AND DIMINISH SOMEWHAT TO A MANAGEABLE RANGE OF 15-20 KNOTS
MAINLY TO THE LOWER END. HIGH SEAS EARLY GET CONFINED TO THE OUTER
WATERS WITH THE WIND SHIFT AND REMAIN THERE FOR THE MOST PART.
SOME FIVE TO SIX FOOTERS MAY LINGER ACROSS THE OUTER WATERS GIVING
THE FRIDAY.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...NORTHEAST FLOW INITIALLY WILL QUICKLY VEER
TO SOUTHEAST AS HIGH PRESSURE WEAKENS AND LEAVES THE WIND FIELD TO
BE FORCED BY LOCAL EFFECTS IE...THE SEABREEZE. THIS WILL OCCUR
LATE SATURDAY AND SUNDAY AS WINDS DROP TO BELOW 10 KNOTS. SEAS
FOLLOW A SIMILAR TREND WITH 2-4 FEET INITIALLY DROPPING TO 2-3 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 10 PM TONIGHT FOR AMZ250-252
DENSE FOG ADVISORY UNTIL 5 PM EST TODAY FOR AMZ254-256.
SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EST THURSDAY
NIGHT FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1135 AM EST WED NOV 16 2011
.SYNOPSIS...
A COLD FRONT OVER THE TENNESSEE VALLEY WILL SLIDE EASTWARD BRINGING
SHOWERS AND A CHANCE OF THUNDERSTORMS...INCLUDING SEVERE
WEATHER...TONIGHT INTO THROUGH THURSDAY MORNING. MUCH COOLER AND
DRIER AIR WILL FOLLOW LATE THURSDAY AND FRIDAY. HIGH PRESSURE WILL
MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING THE WEEKEND.
ANOTHER FRONT WILL SHIFT TOWARD THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...WARM MOIST SOUTHWEST FLOW CONTINUES OVER
THE CAROLINAS TODAY IN ADVANCE OF A STRONG COLD FRONT NOW LOCATED IN
EASTERN TENNESSEE...NORTHERN ALABAMA...AND MISSISSIPPI. TODAY SHOULD
BE THE WARMEST DAY OF THIS ENTIRE STRING OF MILD WEATHER DATING BACK
TO SUNDAY...WITH THIS AFTERNOON`S HIGHS REACHING THE LOWER 80S
INLAND AWAY FROM MARINE INFLUENCES. 850 MB TEMPS IN THE +15C TO
+16C RANGE WOULD BE MORE AT HOME IN JUNE THAN IN NOVEMBER...AND WILL
SUPPORT THESE VERY MILD READINGS. RECORD HIGHS FOR TODAY ARE IN THE
MID TO UPPER 80S ARE SHOULD REMAIN UNTOUCHED.
DEWPOINTS IN THE UPPER 60S PLUS A LONG WIND FETCH ACROSS THE COLD
NEARSHORE COASTAL WATERS IS PRODUCING AREAS OF FOG AND VERY LOW
STRATUS CLOUDS OVER THE OCEAN AND SOME OF THE BEACHES. VISIBILITIES
IN THE 0.25 TO 1 MILE RANGE ARE COMMON ON THE BEACHES AND OUT OVER
THE COASTAL WATERS. AS LONG AS THE SUN IS SHINING TODAY THIS FOG
SHOULD HAVE LITTLE SUCCESS MAKING IT MORE THAN 1 MILE INLAND OR
SO...BUT ANY REMAINING FOG THIS EVENING COULD PUSH FARTHER INLAND.
FIRST WE HAVE TRIMMED BACK POPS TODAY WITH ALL SHORT-TERM GUIDANCE
SUGGESTING WE WILL SEE LITTLE IF ANY SHOWER ACTIVITY OVER OUR
FORECAST AREA BEFORE DARK. WE DID LEAVE A SMALL 20 POP WEST OF I-95
LATE THIS AFTERNOON WHERE ONE OF THE PREVIOUS THREE HRRR RUNS SHOWS
SOME SHOWERS POSSIBLE. THERE IS INSTABILITY (CAPE AROUND 1000 J/KG)
FORECAST TO DEVELOP THIS AFTERNOON BUT TRIGGERS FOR CONVECTION ARE
LARGELY ABSENT.
THE BIG STORY IS THE POTENTIAL FOR SEVERE WEATHER AHEAD OF THE FRONT
TONIGHT. ALTHOUGH SURFACE-BASED CAPE/INSTABILITY IS NOT IMPRESSIVE
AFTER SUNSET THERE IS RATHER LARGE ELEVATED CAPE WHEN PARCELS AT
950/925 MB ARE CONSIDERED. RATHER STEEP LAPSE RATES THROUGH ALL THE
MID AND UPPER LEVELS OF THE ATMOSPHERE WILL BE SUPPORTIVE OF DEEP
CONVECTION. SYNOPTIC FACTORS SUPPORTIVE OF LIFT INCLUDE A
FAVORABLY-POSITIONED JET STREAK MOVING THROUGH THE MID-ATLANTIC
REGION TONIGHT PLACING THE CAROLINAS SQUARELY IN THE FAVORED
RIGHT-ENTRANCE REGION...STRONG AND SLIGHTLY BACKED LOW LEVEL WINDS
RELATIVE TO THE MID AND UPPER LEVEL FLOW PRODUCING 0-6 KM BULK SHEAR
VALUES ON THE ORDER OF 50-70 KT...AND SEVERAL 500 MB VORTICITY
CENTERS PASSING OVER OR JUST NORTH OF OUR FORECAST AREA. THE LATEST
SPC CONVECTIVE OUTLOOK INCREASED SEVERE WEATHER PROBABILITIES FOR
WIND AND TORNADOES...AND WE WOULD NOT BE AT ALL SURPRISED TO SEE
TORNADO WATCHES FOR PORTIONS OF OUR FORECAST AREA THIS EVENING AND
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...FORECAST MODELS HAVE SLOWED DOWN THE
PROGRESSION OF THE COLD FRONT EVER SO SLIGHTLY AND HAVE THEREFORE
EXTENDED POPS ACROSS THE BOARD INTO THE LATE MORNING
HOURS...ESPECIALLY COASTAL AREAS. OTHERWISE INTERESTING
TEMPERATURE FORECAST FOR THURSDAY HIGHS AS THE MAV NUMBERS SHOW NO
WARMING IN WILMINGTON WITH LITTLE ELSEWHERE. WITH THE DOWNSLOPE
FLOW AND COLD AIR ADVECTION NOT THAT IMPRESSIVE...DID ADD A DEGREE
OR TWO TO THE MAV NUMBERS. FOR FRIDAY MORNING WINDS DECOUPLE
INLAND WHILE REMAINING UP SLIGHTLY ALONG THE COAST AND ADJUSTED
MOS NUMBERS ACCORDINGLY. COOL DAY FRIDAY WITH MOST AREAS REMAINING
BELOW 60.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...EXTENDED FORECAST IS RATHER UNEVENTFUL AS
THE PATTERN QUICKLY EVOLVES FROM ZONAL TO RIDGING ACROSS THE
SOUTHEAST...SIMILAR TO THE PATTERN WE HAVE EXPERIENCED THE PAST
FEW DAYS. HPC IS FAVORING A BLEND OF THE GFS/ECMWF AND UKMET.
REALLY THE ONLY FORECAST CHALLENGES INVOLVE LIGHT COASTAL TROUGH
QPF SATURDAY AND A BACKDOOR FRONT TUESDAY. AS FOR THE
FORMER...MAINTAINED A DRY FORECAST AS THE MODELS ARE USUALLY
OVERDONE WITH THE QPF AND IN REALITY IT IS GENERALLY A STRATUS
LAYER. REGARDING THE FRONT...THE LATEST GFS IS MORE BULLISH IN
PUSHING THE FRONT SOUTH WITH THE EFFECTS ONLY BEING AN AIRMASS
CHANGE. THE 0000 UTC ECMWF HAS BACKED OFF A FURTHER SOUTH
SOLUTION. OTHERWISE...AS WE JUST EXPERIENCED...ABOVE NORMAL TO
DOWN RIGHT BALMY CONDITIONS FOR LATE IN THE WEEKEND AND EARLY NEXT
WEEK.
&&
.AVIATION /17Z WEDNESDAY THROUGH MONDAY/...
AS OF 17Z...A LARGE PORTION OF THE CWA HAS SCATTERED OUT...HOWEVER
EXPECT AN MVFR CEILING TO RE-EMERGE AS CU SPREADS OUT INTO A CEILING
DUE TO A PERSISTENT SUBSIDENCE INVERSION. GUSTY SOUTHWEST WINDS WILL
CONTINUE THROUGH THE AFTERNOON HOURS. THIS EVENING...EXPECT IFR
CEILINGS TO COME BACK...AS LOW LEVEL MOISTURE GETS TRAPPED.
CONVECTION AHEAD OF A FRONTAL BOUNDARY WILL AFFECT THE WESTERN
TERMINALS BEFORE MIDNIGHT...WITH THE PRE-FRONTAL TROUGH WITH
MODERATE OMEGA REACHING THE COAST BY 07-08Z. LOOK FOR INTERMITTENT
IFR VISIBILITIES IN THE HEAVY SHOWERS WITH SOME INCREASE IN WINDS.
THE FIRST SET OF CONVECTION WILL MOVE OFFSHORE BEFORE DAYBREAK...MEANWHILE
MORE CONVECTION ASSOCIATED WITH THE FRONT WILL MOVE THROUGH THE CWA
DURING THE DAY...AGAIN WITH INTERMITTENT HEAVY RAIN WITH MODERATE
FRONTAL LIFT. WINDS WILL SHIFT TO THE NORTH AND GUSTY BEHIND THE
FRONT. MODELS INDICATE LOW CEILINGS WILL REMAIN BEHIND THE
FRONT...BUT WOULD NOT BE SURPRISE TO SEE VFR CONDITIONS BY THE END
OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...EXPECT VFR FRIDAY AND SATURDAY...WITH LOWERED
CONFIDENCE FOR POTENTIAL IFR FOG/STRATUS SUNDAY AND MONDAY MORNINGS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...SATELLITE IMAGERY...SURF CAMS...AND
OBSERVATIONS FROM NORTH MYRTLE BEACH AND SOUTHPORT CONTINUE TO
INDICATE EXPANSIVE AREAS OF DENSE SEA FOG THIS MORNING. WE WILL
LIKELY HAVE TO EXTEND THE TIME OF THE DENSE FOG ADVISORY LATER THIS
MORNING AS THE MOIST SOUTHWESTERLY FLOW IS EXPECTED TO CONTINUE
THROUGH TODAY AND INTO THIS EVENING. THERE IS QUITE A THERMAL
GRADIENT ACROSS THE AREA WITH THE FRYING PAN SHOALS BUOY REPORTING
AN AIR TEMP OF 75...WHILE 66-67 DEGREE TEMPS ARE BEING REPORTED ON
THE BEACHES NEAR CAPE FEAR.
SOUTHWESTERLY WINDS AROUND 15 KT WILL INCREASE FURTHER TONIGHT AS
THE GRADIENT TIGHTENS AHEAD OF THE INCOMING STRONG COLD FRONT.
SHOWERS AND THUNDERSTORMS WILL ALSO INCREASE IN COVERAGE TONIGHT.
THE SMALL CRAFT ADVISORY REMAINS IN PLACE FOR THE ROUGHER CONDITIONS
NEAR AND AHEAD OF THE FRONT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...MAIN FORECAST CHALLENGE WILL BE WHEN TO
CONCLUDE THE SMALL CRAFT ADVISORY LATE THURSDAY EVENING. A PERIOD
OF STRONG NORTHERLY WINDS WILL FOLLOW THE FRONT THURSDAY INTO
THURSDAY EVENING. FOR NOW WITH THE TIMING STILL OUT FOUR
PERIODS...WILL NOT TWEAK BUT ISSUE THE DISCLAIMER THE HEADLINE MAY
HAVE TO BE EXTENDED A FEW HOURS. WINDS VEER TO NORTHEASTERLY
FRIDAY AND DIMINISH SOMEWHAT TO A MANAGEABLE RANGE OF 15-20 KNOTS
MAINLY TO THE LOWER END. HIGH SEAS EARLY GET CONFINED TO THE OUTER
WATERS WITH THE WIND SHIFT AND REMAIN THERE FOR THE MOST PART.
SOME FIVE TO SIX FOOTERS MAY LINGER ACROSS THE OUTER WATERS GIVING
THE FRIDAY.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...NORTHEAST FLOW INITIALLY WILL QUICKLY VEER
TO SOUTHEAST AS HIGH PRESSURE WEAKENS AND LEAVES THE WIND FIELD TO
BE FORCED BY LOCAL EFFECTS IE...THE SEABREEZE. THIS WILL OCCUR
LATE SATURDAY AND SUNDAY AS WINDS DROP TO BELOW 10 KNOTS. SEAS
FOLLOW A SIMILAR TREND WITH 2-4 FEET INITIALLY DROPPING TO 2-3 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ250-252-
254-256.
SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EST THURSDAY
NIGHT FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION...CORRECTED
NWS WILMINGTON NC
1126 AM EST WED NOV 16 2011
.SYNOPSIS...
A COLD FRONT OVER THE TENNESSEE VALLEY WILL SLIDE EASTWARD BRINGING
SHOWERS AND A CHANCE OF THUNDERSTORMS...INCLUDING SEVERE
WEATHER...TONIGHT INTO THROUGH THURSDAY MORNING. MUCH COOLER AND
DRIER AIR WILL FOLLOW LATE THURSDAY AND FRIDAY. HIGH PRESSURE WILL
MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING THE WEEKEND.
ANOTHER FRONT WILL SHIFT TOWARD THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...WARM MOIST SOUTHWEST FLOW CONTINUES OVER
THE CAROLINAS TODAY IN ADVANCE OF A STRONG COLD FRONT NOW LOCATED IN
EASTERN TENNESSEE...NORTHERN ALABAMA...AND MISSISSIPPI. TODAY SHOULD
BE THE WARMEST DAY OF THIS ENTIRE STRING OF MILD WEATHER DATING BACK
TO SUNDAY...WITH THIS AFTERNOON`S HIGHS REACHING THE LOWER 80S
INLAND AWAY FROM MARINE INFLUENCES. 850 MB TEMPS IN THE +15C TO
+16C RANGE WOULD BE MORE AT HOME IN JUNE THAN IN NOVEMBER...AND WILL
SUPPORT THESE VERY MILD READINGS. RECORD HIGHS FOR TODAY ARE IN THE
MID TO UPPER 80S AND SHOULD REMAIN UNTOUCHED.
DEWPOINTS IN THE UPPER 60S PLUS A LONG WIND FETCH ACROSS THE COLD
NEARSHORE COASTAL WATERS IS PRODUCING AREAS OF FOG AND VERY LOW
STRATUS CLOUDS OVER THE OCEAN AND SOME OF THE BEACHES. VISIBILITIES
IN THE 0.25 TO 1 MILE RANGE ARE COMMON ON THE BEACHES AND OUT OVER
THE COASTAL WATERS. AS LONG AS THE SUN IS SHINING TODAY THIS FOG
SHOULD HAVE LITTLE SUCCESS MAKING IT MORE THAN 1 MILE INLAND OR
SO...BUT ANY REMAINING FOG THIS EVENING COULD PUSH FARTHER INLAND.
FIRST WE HAVE TRIMMED BACK POPS TODAY WITH ALL SHORT-TERM GUIDANCE
SUGGESTING WE WILL SEE LITTLE IF ANY SHOWER ACTIVITY OVER OUR
FORECAST AREA BEFORE DARK. WE DID LEAVE A SMALL 20 POP WEST OF I-95
LATE THIS AFTERNOON WHERE ONE OF THE PREVIOUS THREE HRRR RUNS SHOWS
SOME SHOWERS POSSIBLE. THERE IS INSTABILITY (CAPE AROUND 1000 J/KG)
FORECAST TO DEVELOP THIS AFTERNOON BUT TRIGGERS FOR CONVECTION ARE
LARGELY ABSENT.
THE BIG STORY IS THE POTENTIAL FOR SEVERE WEATHER AHEAD OF THE FRONT
TONIGHT. ALTHOUGH SURFACE-BASED CAPE/INSTABILITY IS NOT IMPRESSIVE
AFTER SUNSET THERE IS RATHER LARGE ELEVATED CAPE WHEN PARCELS AT
950/925 MB ARE CONSIDERED. RATHER STEEP LAPSE RATES THROUGH ALL THE
MID AND UPPER LEVELS OF THE ATMOSPHERE WILL BE SUPPORTIVE OF DEEP
CONVECTION. SYNOPTIC FACTORS SUPPORTIVE OF LIFT INCLUDE A
FAVORABLY-POSITIONED JET STREAK MOVING THROUGH THE MID-ATLANTIC
REGION TONIGHT PLACING THE CAROLINAS SQUARELY IN THE FAVORED
RIGHT-ENTRANCE REGION...STRONG AND SLIGHTLY BACKED LOW LEVEL WINDS
RELATIVE TO THE MID AND UPPER LEVEL FLOW PRODUCING 0-6 KM BULK SHEAR
VALUES ON THE ORDER OF 50-70 KT...AND SEVERAL 500 MB VORTICITY
CENTERS PASSING OVER OR JUST NORTH OF OUR FORECAST AREA. THE LATEST
SPC CONVECTIVE OUTLOOK INCREASED SEVERE WEATHER PROBABILITIES FOR
WIND AND TORNADOES...AND WE WOULD NOT BE AT ALL SURPRISED TO SEE
TORNADO WATCHES FOR PORTIONS OF OUR FORECAST AREA THIS EVENING AND
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...FORECAST MODELS HAVE SLOWED DOWN THE
PROGRESSION OF THE COLD FRONT EVER SO SLIGHTLY AND HAVE THEREFORE
EXTENDED POPS ACROSS THE BOARD INTO THE LATE MORNING
HOURS...ESPECIALLY COASTAL AREAS. OTHERWISE INTERESTING
TEMPERATURE FORECAST FOR THURSDAY HIGHS AS THE MAV NUMBERS SHOW NO
WARMING IN WILMINGTON WITH LITTLE ELSEWHERE. WITH THE DOWNSLOPE
FLOW AND COLD AIR ADVECTION NOT THAT IMPRESSIVE...DID ADD A DEGREE
OR TWO TO THE MAV NUMBERS. FOR FRIDAY MORNING WINDS DECOUPLE
INLAND WHILE REMAINING UP SLIGHTLY ALONG THE COAST AND ADJUSTED
MOS NUMBERS ACCORDINGLY. COOL DAY FRIDAY WITH MOST AREAS REMAINING
BELOW 60.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...EXTENDED FORECAST IS RATHER UNEVENTFUL AS
THE PATTERN QUICKLY EVOLVES FROM ZONAL TO RIDGING ACROSS THE
SOUTHEAST...SIMILAR TO THE PATTERN WE HAVE EXPERIENCED THE PAST
FEW DAYS. HPC IS FAVORING A BLEND OF THE GFS/ECMWF AND UKMET.
REALLY THE ONLY FORECAST CHALLENGES INVOLVE LIGHT COASTAL TROUGH
QPF SATURDAY AND A BACKDOOR FRONT TUESDAY. AS FOR THE
FORMER...MAINTAINED A DRY FORECAST AS THE MODELS ARE USUALLY
OVERDONE WITH THE QPF AND IN REALITY IT IS GENERALLY A STRATUS
LAYER. REGARDING THE FRONT...THE LATEST GFS IS MORE BULLISH IN
PUSHING THE FRONT SOUTH WITH THE EFFECTS ONLY BEING AN AIRMASS
CHANGE. THE 0000 UTC ECMWF HAS BACKED OFF A FURTHER SOUTH
SOLUTION. OTHERWISE...AS WE JUST EXPERIENCED...ABOVE NORMAL TO
DOWN RIGHT BALMY CONDITIONS FOR LATE IN THE WEEKEND AND EARLY NEXT
WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...SATELLITE AND OBSERVATIONS SHOW IFR/LIFR CONDITIONS
ENTRENCHED OVER MUCH OF THE CWA...A MIXTURE OF STRATUS AND ADVECTION
SEA FOG. EXPECT IFR CONDITIONS TO CONTINUE THROUGH THE MORNING
HOURS...LIFTING OR SCATTERING AROUND 16Z...AS SOUTHWEST FLOW
INCREASES AHEAD OF A COLD FRONT. EXPECT MVFR/NEAR VFR CONDITIONS FOR
THE AFTERNOON HOURS...ONLY TO LOWER TO IFR SHORTLY AFTER 00Z.
TONIGHT...DEEP MOISTURE ASSOCIATED WITH THE COLD FRONT WILL CROSS
THE CWA...REACHING THE COAST BY 09Z. SHOWERS WILL BE SCATTERED TO
NUMEROUS ALONG AND AHEAD OF THE FRONT. LOW PRESSURE ALONG THE COLD
FRONT MAY ACTUALLY HAVE A DRY SLOT WITH IT...BUT CONFIDENCE IS LOW.
EXTENDED OUTLOOK...SHOWERS LINGERING THURSDAY MORNING WILL LIFT OUT
BY LATE MORNING WITH CONDITIONS IMPROVING TO VFR. EXPECT VFR FRIDAY
AND SATURDAY...WITH LOWERED CONFIDENCE FOR POTENTIAL IFR FOG/STRATUS
SUNDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...SATELLITE IMAGERY...SURF CAMS...AND
OBSERVATIONS FROM NORTH MYRTLE BEACH AND SOUTHPORT CONTINUE TO
INDICATE EXPANSIVE AREAS OF DENSE SEA FOG THIS MORNING. WE WILL
LIKELY HAVE TO EXTEND THE TIME OF THE DENSE FOG ADVISORY LATER THIS
MORNING AS THE MOIST SOUTHWESTERLY FLOW IS EXPECTED TO CONTINUE
THROUGH TODAY AND INTO THIS EVENING. THERE IS QUITE A THERMAL
GRADIENT ACROSS THE AREA WITH THE FRYING PAN SHOALS BUOY REPORTING
AN AIR TEMP OF 75...WHILE 66-67 DEGREE TEMPS ARE BEING REPORTED ON
THE BEACHES NEAR CAPE FEAR.
SOUTHWESTERLY WINDS AROUND 15 KT WILL INCREASE FURTHER TONIGHT AS
THE GRADIENT TIGHTENS AHEAD OF THE INCOMING STRONG COLD FRONT.
SHOWERS AND THUNDERSTORMS WILL ALSO INCREASE IN COVERAGE TONIGHT.
THE SMALL CRAFT ADVISORY REMAINS IN PLACE FOR THE ROUGHER CONDITIONS
NEAR AND AHEAD OF THE FRONT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...MAIN FORECAST CHALLENGE WILL BE WHEN TO
CONCLUDE THE SMALL CRAFT ADVISORY LATE THURSDAY EVENING. A PERIOD
OF STRONG NORTHERLY WINDS WILL FOLLOW THE FRONT THURSDAY INTO
THURSDAY EVENING. FOR NOW WITH THE TIMING STILL OUT FOUR
PERIODS...WILL NOT TWEAK BUT ISSUE THE DISCLAIMER THE HEADLINE MAY
HAVE TO BE EXTENDED A FEW HOURS. WINDS VEER TO NORTHEASTERLY
FRIDAY AND DIMINISH SOMEWHAT TO A MANAGEABLE RANGE OF 15-20 KNOTS
MAINLY TO THE LOWER END. HIGH SEAS EARLY GET CONFINED TO THE OUTER
WATERS WITH THE WIND SHIFT AND REMAIN THERE FOR THE MOST PART.
SOME FIVE TO SIX FOOTERS MAY LINGER ACROSS THE OUTER WATERS GIVING
THE FRIDAY.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...NORTHEAST FLOW INITIALLY WILL QUICKLY VEER
TO SOUTHEAST AS HIGH PRESSURE WEAKENS AND LEAVES THE WIND FIELD TO
BE FORCED BY LOCAL EFFECTS IE...THE SEABREEZE. THIS WILL OCCUR
LATE SATURDAY AND SUNDAY AS WINDS DROP TO BELOW 10 KNOTS. SEAS
FOLLOW A SIMILAR TREND WITH 2-4 FEET INITIALLY DROPPING TO 2-3 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ250-252-
254-256.
SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EST THURSDAY
NIGHT FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1052 AM EST WED NOV 16 2011
.SYNOPSIS...
A COLD FRONT OVER THE TENNESSEE VALLEY WILL SLIDE EASTWARD BRINGING
SHOWERS AND A CHANCE OF THUNDERSTORMS...INCLUDING SEVERE
WEATHER...TONIGHT INTO THROUGH THURSDAY MORNING. MUCH COOLER AND
DRIER AIR WILL FOLLOW LATE THURSDAY AND FRIDAY. HIGH PRESSURE WILL
MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING THE WEEKEND.
ANOTHER FRONT WILL SHIFT TOWARD THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...WARM MOIST SOUTHWEST FLOW CONTINUES OVER
THE CAROLINAS TODAY IN ADVANCE OF A STRONG COLD FRONT NOW LOCATED IN
EASTERN TENNESSEE...NORTHERN ALABAMA...AND MISSISSIPPI. TODAY SHOULD
BE THE WARMEST DAY OF THIS ENTIRE STRING OF MILD WEATHER DATING BACK
TO SUNDAY...WITH THIS AFTERNOON`S HIGHS REACHING THE LOWER 80S
INLAND AWAY FROM MARINE INFLUENCES. 850 MB TEMPS IN THE +15C TO
+16C RANGE WOULD BE MORE AT HOME IN JUNE THAN IN NOVEMBER...AND WILL
SUPPORT THESE VERY MILD READINGS. RECORD HIGHS FOR TODAY ARE IN THE
MID TO UPPER 80S ARE SHOULD REMAIN UNTOUCHED.
DEWPOINTS IN THE UPPER 60S PLUS A LONG WIND FETCH ACROSS THE COLD
NEARSHORE COASTAL WATERS IS PRODUCING AREAS OF FOG AND VERY LOW
STRATUS CLOUDS OVER THE OCEAN AND SOME OF THE BEACHES. VISIBILITIES
IN THE 0.25 TO 1 MILE RANGE ARE COMMON ON THE BEACHES AND OUT OVER
THE COASTAL WATERS. AS LONG AS THE SUN IS SHINING TODAY THIS FOG
SHOULD HAVE LITTLE SUCCESS MAKING IT MORE THAN 1 MILE INLAND OR
SO...BUT ANY REMAINING FOG THIS EVENING COULD PUSH FARTHER INLAND.
FIRST WE HAVE TRIMMED BACK POPS TODAY WITH ALL SHORT-TERM GUIDANCE
SUGGESTING WE WILL SEE LITTLE IF ANY SHOWER ACTIVITY OVER OUR
FORECAST AREA BEFORE DARK. WE DID LEAVE A SMALL 20 POP WEST OF I-95
LATE THIS AFTERNOON WHERE ONE OF THE PREVIOUS THREE HRRR RUNS SHOWS
SOME SHOWERS POSSIBLE. THERE IS INSTABILITY (CAPE AROUND 1000 J/KG)
FORECAST TO DEVELOP THIS AFTERNOON BUT TRIGGERS FOR CONVECTION ARE
LARGELY ABSENT.
THE BIG STORY IS THE POTENTIAL FOR SEVERE WEATHER AHEAD OF THE FRONT
TONIGHT. ALTHOUGH SURFACE-BASED CAPE/INSTABILITY IS NOT IMPRESSIVE
AFTER SUNSET THERE IS RATHER LARGE ELEVATED CAPE WHEN PARCELS AT
950/925 MB ARE CONSIDERED. RATHER STEEP LAPSE RATES THROUGH ALL THE
MID AND UPPER LEVELS OF THE ATMOSPHERE WILL BE SUPPORTIVE OF DEEP
CONVECTION. SYNOPTIC FACTORS SUPPORTIVE OF LIFT INCLUDE A
FAVORABLY-POSITIONED JET STREAK MOVING THROUGH THE MID-ATLANTIC
REGION TONIGHT PLACING THE CAROLINAS SQUARELY IN THE FAVORED
RIGHT-ENTRANCE REGION...STRONG AND SLIGHTLY BACKED LOW LEVEL WINDS
RELATIVE TO THE MID AND UPPER LEVEL FLOW PRODUCING 0-6 KM BULK SHEAR
VALUES ON THE ORDER OF 50-70 KT...AND SEVERAL 500 MB VORTICITY
CENTERS PASSING OVER OR JUST NORTH OF OUR FORECAST AREA. THE LATEST
SPC CONVECTIVE OUTLOOK INCREASED SEVERE WEATHER PROBABILITIES FOR
WIND AND TORNADOES...AND WE WOULD NOT BE AT ALL SURPRISED TO SEE
TORNADO WATCHES FOR PORTIONS OF OUR FORECAST AREA THIS EVENING AND
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...FORECAST MODELS HAVE SLOWED DOWN THE
PROGRESSION OF THE COLD FRONT EVER SO SLIGHTLY AND HAVE THEREFORE
EXTENDED POPS ACROSS THE BOARD INTO THE LATE MORNING
HOURS...ESPECIALLY COASTAL AREAS. OTHERWISE INTERESTING
TEMPERATURE FORECAST FOR THURSDAY HIGHS AS THE MAV NUMBERS SHOW NO
WARMING IN WILMINGTON WITH LITTLE ELSEWHERE. WITH THE DOWNSLOPE
FLOW AND COLD AIR ADVECTION NOT THAT IMPRESSIVE...DID ADD A DEGREE
OR TWO TO THE MAV NUMBERS. FOR FRIDAY MORNING WINDS DECOUPLE
INLAND WHILE REMAINING UP SLIGHTLY ALONG THE COAST AND ADJUSTED
MOS NUMBERS ACCORDINGLY. COOL DAY FRIDAY WITH MOST AREAS REMAINING
BELOW 60.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...EXTENDED FORECAST IS RATHER UNEVENTFUL AS
THE PATTERN QUICKLY EVOLVES FROM ZONAL TO RIDGING ACROSS THE
SOUTHEAST...SIMILAR TO THE PATTERN WE HAVE EXPERIENCED THE PAST
FEW DAYS. HPC IS FAVORING A BLEND OF THE GFS/ECMWF AND UKMET.
REALLY THE ONLY FORECAST CHALLENGES INVOLVE LIGHT COASTAL TROUGH
QPF SATURDAY AND A BACKDOOR FRONT TUESDAY. AS FOR THE
FORMER...MAINTAINED A DRY FORECAST AS THE MODELS ARE USUALLY
OVERDONE WITH THE QPF AND IN REALITY IT IS GENERALLY A STRATUS
LAYER. REGARDING THE FRONT...THE LATEST GFS IS MORE BULLISH IN
PUSHING THE FRONT SOUTH WITH THE EFFECTS ONLY BEING AN AIRMASS
CHANGE. THE 0000 UTC ECMWF HAS BACKED OFF A FURTHER SOUTH
SOLUTION. OTHERWISE...AS WE JUST EXPERIENCED...ABOVE NORMAL TO
DOWN RIGHT BALMY CONDITIONS FOR LATE IN THE WEEKEND AND EARLY NEXT
WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...SATELLITE AND OBSERVATIONS SHOW IFR/LIFR CONDITIONS
ENTRENCHED OVER MUCH OF THE CWA...A MIXTURE OF STRATUS AND ADVECTION
SEA FOG. EXPECT IFR CONDITIONS TO CONTINUE THROUGH THE MORNING
HOURS...LIFTING OR SCATTERING AROUND 16Z...AS SOUTHWEST FLOW
INCREASES AHEAD OF A COLD FRONT. EXPECT MVFR/NEAR VFR CONDITIONS FOR
THE AFTERNOON HOURS...ONLY TO LOWER TO IFR SHORTLY AFTER 00Z.
TONIGHT...DEEP MOISTURE ASSOCIATED WITH THE COLD FRONT WILL CROSS
THE CWA...REACHING THE COAST BY 09Z. SHOWERS WILL BE SCATTERED TO
NUMEROUS ALONG AND AHEAD OF THE FRONT. LOW PRESSURE ALONG THE COLD
FRONT MAY ACTUALLY HAVE A DRY SLOT WITH IT...BUT CONFIDENCE IS LOW.
EXTENDED OUTLOOK...SHOWERS LINGERING THURSDAY MORNING WILL LIFT OUT
BY LATE MORNING WITH CONDITIONS IMPROVING TO VFR. EXPECT VFR FRIDAY
AND SATURDAY...WITH LOWERED CONFIDENCE FOR POTENTIAL IFR FOG/STRATUS
SUNDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM WEDNESDAY...SATELLITE IMAGERY...SURF CAMS...AND
OBSERVATIONS FROM NORTH MYRTLE BEACH AND SOUTHPORT CONTINUE TO
INDICATE EXPANSIVE AREAS OF DENSE SEA FOG THIS MORNING. WE WILL
LIKELY HAVE TO EXTEND THE TIME OF THE DENSE FOG ADVISORY LATER THIS
MORNING AS THE MOIST SOUTHWESTERLY FLOW IS EXPECTED TO CONTINUE
THROUGH TODAY AND INTO THIS EVENING. THERE IS QUITE A THERMAL
GRADIENT ACROSS THE AREA WITH THE FRYING PAN SHOALS BUOY REPORTING
AN AIR TEMP OF 75...WHILE 66-67 DEGREE TEMPS ARE BEING REPORTED ON
THE BEACHES NEAR CAPE FEAR.
SOUTHWESTERLY WINDS AROUND 15 KT WILL INCREASE FURTHER TONIGHT AS
THE GRADIENT TIGHTENS AHEAD OF THE INCOMING STRONG COLD FRONT.
SHOWERS AND THUNDERSTORMS WILL ALSO INCREASE IN COVERAGE TONIGHT.
THE SMALL CRAFT ADVISORY REMAINS IN PLACE FOR THE ROUGHER CONDITIONS
NEAR AND AHEAD OF THE FRONT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...MAIN FORECAST CHALLENGE WILL BE WHEN TO
CONCLUDE THE SMALL CRAFT ADVISORY LATE THURSDAY EVENING. A PERIOD
OF STRONG NORTHERLY WINDS WILL FOLLOW THE FRONT THURSDAY INTO
THURSDAY EVENING. FOR NOW WITH THE TIMING STILL OUT FOUR
PERIODS...WILL NOT TWEAK BUT ISSUE THE DISCLAIMER THE HEADLINE MAY
HAVE TO BE EXTENDED A FEW HOURS. WINDS VEER TO NORTHEASTERLY
FRIDAY AND DIMINISH SOMEWHAT TO A MANAGEABLE RANGE OF 15-20 KNOTS
MAINLY TO THE LOWER END. HIGH SEAS EARLY GET CONFINED TO THE OUTER
WATERS WITH THE WIND SHIFT AND REMAIN THERE FOR THE MOST PART.
SOME FIVE TO SIX FOOTERS MAY LINGER ACROSS THE OUTER WATERS GIVING
THE FRIDAY.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...NORTHEAST FLOW INITIALLY WILL QUICKLY VEER
TO SOUTHEAST AS HIGH PRESSURE WEAKENS AND LEAVES THE WIND FIELD TO
BE FORCED BY LOCAL EFFECTS IE...THE SEABREEZE. THIS WILL OCCUR
LATE SATURDAY AND SUNDAY AS WINDS DROP TO BELOW 10 KNOTS. SEAS
FOLLOW A SIMILAR TREND WITH 2-4 FEET INITIALLY DROPPING TO 2-3 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ250-252-
254-256.
SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EST THURSDAY
NIGHT FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
300 AM EST WED NOV 16 2011
.SYNOPSIS...
A COLD FRONT OVER THE TENNESSEE VALLEY WILL SLIDE EASTWARD
BRINGING SHOWERS AND A CHANCE OF THUNDERSTORMS THROUGH THURSDAY MORNING.
MUCH COOLER AND DRIER AIR WILL FOLLOW LATE THURSDAY AND FRIDAY. HIGH
PRESSURE WILL MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING
THE WEEKEND. ANOTHER FRONT WILL SHIFT TOWARD THE AREA EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 3:00 AM WEDNESDAY...MORNING LOW STRATUS WILL BURN OFF DURING THE
MID TO LATE MORNING HOURS. PATCHY SEA FOG OFFSHORE MAY ENCROACH ONTO
THE BEACHES AND NEARBY ENVIRONS FOR AT LEAST THE FIRST HALF OF THE
DAY. VISIBILITIES MAY BE REDUCED TO A MILE OR LESS IN A FEW PLACES.
SOME HIGHER CLOUDS WILL BE IN PLACE THROUGH THE DAY. AS WE MIX DRIER
AIR TO THE SURFACE...SKIES WILL BECOME AT LEAST PARTLY CLOUDY. WINDS
ALOFT WILL BE SW AT 30 TO 40 KT AND AS WE MIX TO A DEPTH OF AROUND 3
KFT...WE WILL EXPERIENCE WIND GUSTS OF NEAR 30 MPH LATE MORNING AND
THROUGH THE AFTERNOON AND EVE.
A STRONG COLD FRONT WILL BE APPROACHING FROM THE NW TODAY. A SERIES
OF SURFACE LOWS WILL TRAVERSE THIS BOUNDARY. THE FRONT IS EXPECTED
TO REACH THE I-95 CORRIDOR DURING THE LATE EVE AND THEN MOVE ACROSS
THE FORECAST AREA DURING THE EARLY MORNING HOURS OF THU...AND
FINALLY OFF THE COAST DURING THU MORNING. DEEP SW FLOW WILL ALLOW
PRECIPITABLE WATER VALUES TO RISE TO AROUND ONE AND A HALF INCHES.
SUFFICIENT FORCING TO GENERATE PRECIPITATION MAY NOT ARRIVE TO WELL
AFTER DARK.
LOW LEVEL JET WILL INCREASE TO AROUND 50 KT OVERNIGHT. MODELS ARE
INDICATING AN INVERSION AROUND 1400 FT TONIGHT AND THIS WILL MAKE IT
DIFFICULT FOR HIGHER WINDS ALOFT TO REACH THE GROUND. HOWEVER...ONE
AREA OF LOW PRESSURE WILL LIKELY BE MOVING ALONG AND N OF OUR INLAND
ZONES OVERNIGHT. BULK SHEAR VALUES ARE FORECAST TO BE NEAR OR OVER
60 KT DURING THE LATE NIGHT AND EARLY MORNING HOURS...HIGHEST NEAR
THE TRACK OF THE SURFACE LOW. LCLS WILL BE DROPPING DURING THIS
TIME. THIS SUPPORTS AN ISOLATED RISK FOR TORNADOES. SPC HAS A
PORTION OF THE FORECAST AREA IN A SLIGHT RISK FOR SEVERE
WEATHER...INCLUDING TORNADOES. CURRENTLY THE RISK AREA IS ACROSS THE
PEE DEE REGION OF SOUTH CAROLINA AND FROM NEAR FAIR BLUFF TO BURGAW
IN NORTH CAROLINA AND POINTS NORTH. THIS AREA MAY SHIFT THROUGH THE
DAY...BUT AT THIS TIME IT IS REASONABLE TO EXPECT SOME RISK OF
ISOLATED TORNADOES OR DAMAGING WIND GUSTS ACROSS A MAJORITY OF THE
AREA.
POPS WILL BE HIGHEST LATE TONIGHT...CATEGORICAL NW ZONES TO LIKELY
AS YOU APPROACH THE COAST WITH CONVECTION LINGERING ALONG THE COAST
THROUGH THU MORNING. CURRENT PRECIPITATION FORECAST INCLUDES AMOUNTS
IN THE ONE-HALF INCH TO ONE-INCH RANGE...BUT AMOUNTS SHOULD BE
HIGHLY VARIABLE AS YOU MOVE FROM ONE COMMUNITY TO THE NEXT.
FORECAST
TEMPS WILL BE WELL ABOVE NORMAL WITH HIGHS IN THE UPPER 70S TO LOWER
80S EXCEPT ALONG THE IMMEDIATE COAST WHERE THE COMPARATIVELY COOL
MARINE ENVIRONMENT WILL KEEP READINGS IN THE LOWER TO PERHAPS MID
70S. TEMPS TONIGHT WILL BE IN THE BALMY 70S FOR MOST OF THE EVE WITH
MINIMUMS ACROSS MOST OF THE AREA PROJECTED TO FALL ONLY TO THE LOWER
TO MID 60S BY SUNRISE THU.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY EVENING/...
AS OF 3:00 AM WEDNESDAY...FORECAST MODELS HAVE SLOWED DOWN THE PROGRESSION OF
THE COLD FRONT EVER SO SLIGHTLY AND HAVE THEREFORE EXTENDED POPS
ACROSS THE BOARD INTO THE LATE MORNING HOURS...ESPECIALLY COASTAL
AREAS. OTHERWISE INTERESTING TEMPERATURE FORECAST FOR THURSDAY HIGHS
AS THE MAV NUMBERS SHOW NO WARMING IN WILMINGTON WITH LITTLE
ELSEWHERE. WITH THE DOWNSLOPE FLOW AND COLD AIR ADVECTION NOT THAT
IMPRESSIVE...DID ADD A DEGREE OR TWO TO THE MAV NUMBERS. FOR FRIDAY
MORNING WINDS DECOUPLE INLAND WHILE REMAINING UP SLIGHTLY ALONG THE
COAST AND ADJUSTED MOS NUMBERS ACCORDINGLY. COOL DAY FRIDAY WITH
MOST AREAS REMAINING BELOW 60.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3:00 AM WEDNESDAY...EXTENDED FORECAST IS RATHER UNEVENTFUL AS THE
PATTERN QUICKLY EVOLVES FROM ZONAL TO RIDGING ACROSS THE
SOUTHEAST...SIMILAR TO THE PATTERN WE HAVE EXPERIENCED THE PAST
FEW DAYS. HPC IS FAVORING A BLEND OF THE GFS/ECMWF AND UKMET.
REALLY THE ONLY FORECAST CHALLENGES INVOLVE LIGHT COASTAL TROUGH
QPF SATURDAY AND A BACKDOOR FRONT TUESDAY. AS FOR THE
FORMER...MAINTAINED A DRY FORECAST AS THE MODELS ARE USUALLY
OVERDONE WITH THE QPF AND IN REALITY IT IS GENERALLY A STRATUS
LAYER. REGARDING THE FRONT...THE LATEST GFS IS MORE BULLISH IN
PUSHING THE FRONT SOUTH WITH THE EFFECTS ONLY BEING AN AIRMASS
CHANGE. THE 0000 UTC ECMWF HAS BACKED OFF A FURTHER SOUTH
SOLUTION. OTHERWISE...AS WE JUST EXPERIENCED...ABOVE NORMAL TO
DOWN RIGHT BALMY CONDITIONS FOR LATE IN THE WEEKEND AND EARLY NEXT
WEEK.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...HIGH CONFIDENCE IFR CEILINGS OR LOWER WILL DOMINATE
THROUGH THE FIRST 6 TO 9 HOURS AT ALL THE TERMINALS. VISIBILITY WILL
FLUCTUATE FROM MVFR TO IFR OR LOWER IN FOG.
EARLIER LIGHT RAIN AT KILM HAS ENDED AS SHOWERS CONTINUE TO PULL
AWAY FROM THE CAPE FEAR REGION. PATCHY SEA FOG WILL CONTINUE
OFFSHORE AND MAY COME ONTO THE COAST BRINGING BOUTS OF LOWER
VISIBILITY TO THE COASTAL TERMINALS BEFORE WINDS VEER MORE SOLIDLY
SW BY/AFTER SUNRISE.
CONDITIONS WILL SLOWLY IMPROVE TO VFR MID-MORNING THROUGH MIDDAY.
TIGHTENING PRESSURE GRADIENT AHEAD OF COLD FRONT WILL CREATE GUSTY
SW WINDS...18-22KTS AT ALL TAF SITES LATE MORNING AND THROUGH THE
AFTERNOON AND EARLY EVE.
TOWARD THE END OF THE VALID PERIOD AND THEREAFTER...CONDITIONS WILL
SLOWLY BEGIN TO DETERIORATE AGAIN AS A COLD FRONT BRINGS SHRA AND
ISOLATED TSRA LATE TONIGHT AND THU MORNING.
EXTENDED OUTLOOK...COLD FRONT MOVING ACROSS THE AREA OVERNIGHT INTO
THURSDAY MORNING COULD CREATE ISOLATED IFR IN TSRA. EXPECT VFR
FRIDAY AND SATURDAY...WITH LOWERED CONFIDENCE FOR POTENTIAL IFR
FOG/STRATUS SUNDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 PM TUESDAY...THE SEA FOG THREAT CONTINUES ACROSS THE ILM
WATERS. WILL CONTINUE TO INDICATE PATCHY/AREAS OF SEA FOG ACROSS THE
ILM WATERS THROUGH OR JUST AFTER DAYBREAK WEDNESDAY. WITH THE LATEST
AVAILABLE SST MAP OF THE ILM WATERS USING AVHRR DATA FOR THE 2 DAYS
ENDING ON NOV 14TH...2 NOTEWORTHY PATCHES OF COOLER SHELF WATERS IN
THE LOW 60S WERE SHOWN. ONE PATCH BETWEEN SURF CITY AND CAPE
FEAR...AND OUT TO NEARLY THE FRYING PAN SHOALS BUOY...41013. AND THE
2ND PATCH...LYING ACROSS THE WATERS BETWEEN NORTH MYRTLE BEACH TO
SOUTH SANTEE RIVER. THIS 2ND ONE NOT NEARLY AS PRONOUNCED AS THE
1ST. SFC DEWPOINTS IN THE MID 60S TO NEAR 70 WILL CONTINUE TO ADVECT
ACROSS THESE COOLER SHELF WATERS OVERNIGHT INTO WED. THIS WILL
RESULT WITH AN INCREASED POTENTIAL FOR SEA FOG TO DEVELOP AND AFFECT
THE ILM WATERS...PARTICULAR ACROSS THOSE COOL WATERS. A FEW LOCAL
SURF CAMS HAVE SHOWCASED THE EXISTENCE OF THE SEA FOG. AS SYNOPTIC
WINDS SLOWLY VEER FROM 190-230 OVERNIGHT INTO WED...THE THREAT FOR
SEA FOG WILL SLOWLY DIMINISH OR AT LEAST KEEP THE FOG FROM
ADVECTING ONSHORE/INLAND. WILL INDICATE VSBY REDUCING TO 1NM OR
LESS. IF ANY RECEIVED REPORTS AND/OR OBS INDICATE 1/2 NM OR LESS
VSBYS...WILL THEN UPDATE AND ADVERTISE DENSE FOG. A MARINE WEATHER
STATEMENT HAS BEEN ISSUED TO HIGHLIGHT THE INCREASED POTENTIAL FOR
SEA FOG.
HAVE MAINTAINED THE WINDS AND SEAS FORECAST FROM THE PREVIOUS
FORECAST...WITH THE LATEST HRRR KEEPING WINDS ON THE LOWER SIDE OF
MODEL GUIDANCE. WHICH IN TURN...PRODUCING SLIGHTLY LOWER SEAS THAN
ORIGINALLY THOUGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3:00 AM WEDNESDAY...MAIN FORECAST CHALLENGE WILL BE WHEN TO
CONCLUDE THE SMALL CRAFT ADVISORY LATE THURSDAY EVENING. A PERIOD OF
STRONG NORTHERLY WINDS WILL FOLLOW THE FRONT THURSDAY INTO THURSDAY
EVENING. FOR NOW WITH THE TIMING STILL OUT FOUR PERIODS...WILL NOT
TWEAK BUT ISSUE THE DISCLAIMER THE HEADLINE MAY HAVE TO BE EXTENDED
A FEW HOURS. WINDS VEER TO NORTHEASTERLY FRIDAY AND DIMINISH
SOMEWHAT TO A MANAGEABLE RANGE OF 15-20 KNOTS MAINLY TO THE LOWER
END. HIGH SEAS EARLY GET CONFINED TO THE OUTER WATERS WITH THE WIND
SHIFT AND REMAIN THERE FOR THE MOST PART. SOME FIVE TO SIX FOOTERS
MAY LINGER ACROSS THE OUTER WATERS GIVING THE FRIDAY.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3:00 AM WEDNESDAY...NORTHEAST FLOW INITIALLY WILL QUICKLY VEER TO
SOUTHEAST AS HIGH PRESSURE WEAKENS AND LEAVES THE WIND FIELD TO BE
FORCED BY LOCAL EFFECTS IE...THE SEABREEZE. THIS WILL OCCUR LATE
SATURDAY AND SUNDAY AS WINDS DROP TO BELOW 10 KNOTS. SEAS FOLLOW A
SIMILAR TREND WITH 2-4 FEET INITIALLY DROPPING TO 2-3 FEET.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EST THURSDAY
NIGHT FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...RJD
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1222 AM EST WED NOV 16 2011
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OVER THE REGION THROUGH WEDNESDAY.
A COLD FRONT OVER THE MIDWEST WILL SLIDE EASTWARD BRINGING SHOWERS
AND A CHANCE OF THUNDERSTORMS OVERNIGHT WEDNESDAY INTO THURSDAY.
MUCH COOLER AND DRIER AIR WILL FOLLOW ON THURSDAY AND FRIDAY. HIGH
PRESSURE WILL MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING THE
WEEKEND. A SECOND FRONT WILL SHIFT TOWARD THE AREA ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM TUESDAY...SPORADIC ONSHORE MOVEMENT OF PATCHY OR AREAS
OF SEA FOG WILL CONTINUE OVERNIGHT. THIS A RESULT OF SFC WINDS
BOUNCING FROM 180-210 DEGREES. AS WINDS BECOME DOMINANT 210-230
DEGREE DIRECTION AFTER DAYBREAK WEDNESDAY...THE THREAT FOR SEA FOG
MOVING ONSHORE WILL DIMINISH GREATLY. SCATTERED -SHRA LATE THIS
EVENING AND OVERNIGHT DUE TO A WEAK LOW-MID LEVEL IMPULSE TRACKING
NE...AS WELL AS LOW LEVEL WIND SPEED CONVERGENCE FROM 15-25 KT S-SW
WINDS OFFSHORE QUICKLY DROPPING TO 10 KT OR LESS OVER THE COOLER
SHELF WATERS...AS WELL AS WEAK WIND DIRECTION CONVERGENCE FROM SW
INLAND TO S-SSW ALONG THE IMMEDIATE COAST.
AS FOR SEA FOG...THE LATEST AVAILABLE SST MAP OF THE WATERS OFF THE
SOUTHEAST U.S. COAST USING AVHRR DATA FOR THE 2 DAYS ENDING ON NOV
14TH...INDICATED 2 PATCHES OF NOTEWORTHY COOL SHELF WATERS OFF THE
CAROLINAS...WITH 1 PATCH BETWEEN SURF CITY AND CAPE FEAR...TO NEARLY
OUT TO THE FRYING PAN SHOALS BUOY...41013. AND THE SECOND PATCH
LYING ACROSS THE COASTAL WATERS BETWEEN NORTH MYRTLE BEACH TO SOUTH
SANTEE RIVER. THIS 2ND ONE NOT AS PRONOUNCED AS THE 1ST. WITH SFC
DEWPOINTS IN THE MID 60S TO NEAR 70 ADVECTING ACROSS THESE COOLER
SHELF WATERS OVERNIGHT INTO WED...SEA FOG WILL CONTINUE TO DEVELOP
AND AFFECT THE IMMEDIATE COAST BORDERING THE AFOREMENTIONED COLL
SHELF WATER AREAS. A FEW LOCAL SURF CAMS HAVE ALSO SHOWCASED THE
EXISTENCE OF THE SEA FOG AT TIMES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A LARGE SCALE UPPER LEVEL TROUGH OVER THE
WESTERN UNITED STATES WILL SHIFT EASTWARD BY WEDNESDAY NIGHT AND
THIS WILL PROVIDE GOOD SYNOPTIC LIFT FOR THE REGION. AT THE SURFACE
A FRONTAL BOUNDARY WILL ACT AS THE LOW LEVEL LIFTING MECHANISM FOR
SHOWERS AND ISOLATED THUNDERSTORMS. INSTABILITY IS FORECAST BY THE
MODEL TO BE VERY LOW AND THE LOW-LEVEL 0 TO 2.5 KM BULK SHEAR
MAGNITUDE REACHES ALMOST 40 KNOTS. THE LOW-LEVEL HELICITY MAXIMUM
APPEARS TO BE SHIFTING FARTHER NORTH WITH THIS MODEL RUN AND IS
RUNNING AHEAD OF THE MODEL CONVECTION...SO CONFIDENCE ON ISOLATED
TORNADOES IS NOT VERY HIGH AT THIS TIME.
MAXIMUM TEMPERATURES ARE EXPECTED TO REACH IN THE UPPER 70S INLAND
ON WEDNESDAY AND WITH THE FRONTAL BOUNDARY PASSAGE HIGHS ARE
EXPECTED TO ONLY REACH IN THE LOWER TO MIDDLE 60S ON THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...COLD SURFACE HIGH BUILDS INTO THE REGION FRI
BEFORE QUICKLY SHIFTING NORTHEAST FRI NIGHT INTO SAT. WEAK COASTAL
TROUGH DEVELOPS SAT WITH LOW LEVEL EAST TO NORTHEAST FLOW
INCREASING MOISTURE IN THE LOWEST 3K FT OR SO. CURRENT FORECAST IS
DEVOID OF PRECIP HOWEVER THE INCREASE IN LOW LEVEL MOISTURE
COMBINED WITH DEVELOPING RETURN FLOW JUST ABOVE THE SURFACE LATER
IN THE DAY SAT COULD PRODUCE SOME LIGHT PATCHY OF RAIN. WOULD NOT
EXPECT MUCH QPF SHOULD SOMETHING DEVELOP WITH COASTAL NC THE MOST
LIKELY AREA TO SEE SOMETHING. AT THE VERY LEAST ANTICIPATE AN
INCREASE IN CLOUD COVER SAT INTO SUN.
COASTAL TROUGH DISSIPATES SUN AS SURFACE RIDGE AXIS SHIFTS EAST OF
THE AREA. ALTHOUGH DEVELOPING SOUTHERLY FLOW HELPS INCREASE LOW
LEVEL MOISTURE SUN AND MON DRY MID LEVELS AND WEAK CAP...A RESULT OF
BUILDING WEAK MID LEVEL RIDGE...WILL PREVENT ANY PRECIP. WEAK COLD
FRONT STALLED NORTH OF THE AREA TUE WILL TRY AND DROP SOUTH DURING
THE DAY. IF FRONT MOVES ACROSS THE AREA DO NOT THINK IT WOULD HAVE
MUCH PRECIP ASSOCIATED WITH IT. THE FRONT IS STRETCHED OUT WITH THE
DYNAMICS WELL OFF TO THE NORTHEAST.
TEMPERATURES WILL RANGE FROM WELL BELOW CLIMO AT THE START OF THE
PERIOD TO ABOVE CLIMO EARLY NEXT WEEK. THE TRANSITION FROM BELOW
CLIMO TO ABOVE WILL BE QUICK...BY SAT NIGHT TEMPS SHOULD BE ABOVE
CLIMO.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...HIGH CONFIDENCE IFR CEILINGS OR LOWER WILL DOMINATE
THROUGH THE FIRST 6 TO 9 HOURS AT ALL THE TERMINALS. VISIBILITY WILL
FLUCTUATE FROM MVFR TO IFR OR LOWER IN FOG.
EARLIER LIGHT RAIN AT KILM HAS ENDED AS SHOWERS CONTINUE TO PULL
AWAY FROM THE CAPE FEAR REGION. PATCHY SEA FOG WILL CONTINUE
OFFSHORE AND MAY COME ONTO THE COAST BRINGING BOUTS OF LOWER
VISIBILITY TO THE COASTAL TERMINALS BEFORE WINDS VEER MORE SOLIDLY
SW BY/AFTER SUNRISE.
CONDITIONS WILL SLOWLY IMPROVE TO VFR MID-MORNING THROUGH MIDDAY.
TIGHTENING PRESSURE GRADIENT AHEAD OF COLD FRONT WILL CREATE GUSTY
SW WINDS...18-22KTS AT ALL TAF SITES LATE MORNING AND THROUGH THE
AFTERNOON AND EARLY EVE.
TOWARD THE END OF THE VALID PERIOD AND THEREAFTER...CONDITIONS WILL
SLOWLY BEGIN TO DETERIORATE AGAIN AS A COLD FRONT BRINGS SHRA AND
ISOLATED TSRA LATE TONIGHT AND THU MORNING.
EXTENDED OUTLOOK...COLD FRONT MOVING ACROSS THE AREA OVERNIGHT INTO
THURSDAY MORNING COULD CREATE ISOLATED IFR IN TSRA. EXPECT VFR
FRIDAY AND SATURDAY...WITH LOWERED CONFIDENCE FOR POTENTIAL IFR
FOG/STRATUS SUNDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 PM TUESDAY...THE SEA FOG THREAT CONTINUES ACROSS THE ILM
WATERS. WILL CONTINUE TO INDICATE PATCHY/AREAS OF SEA FOG ACROSS THE
ILM WATERS THROUGH OR JUST AFTER DAYBREAK WEDNESDAY. WITH THE LATEST
AVAILABLE SST MAP OF THE ILM WATERS USING AVHRR DATA FOR THE 2 DAYS
ENDING ON NOV 14TH...2 NOTEWORTHY PATCHES OF COOLER SHELF WATERS IN
THE LOW 60S WERE SHOWN. ONE PATCH BETWEEN SURF CITY AND CAPE
FEAR...AND OUT TO NEARLY THE FRYING PAN SHOALS BUOY...41013. AND THE
2ND PATCH...LYING ACROSS THE WATERS BETWEEN NORTH MYRTLE BEACH TO
SOUTH SANTEE RIVER. THIS 2ND ONE NOT NEARLY AS PRONOUNCED AS THE
1ST. SFC DEWPOINTS IN THE MID 60S TO NEAR 70 WILL CONTINUE TO ADVECT
ACROSS THESE COOLER SHELF WATERS OVERNIGHT INTO WED. THIS WILL
RESULT WITH AN INCREASED POTENTIAL FOR SEA FOG TO DEVELOP AND AFFECT
THE ILM WATERS...PARTICULAR ACROSS THOSE COOL WATERS. A FEW LOCAL
SURF CAMS HAVE SHOWCASED THE EXISTENCE OF THE SEA FOG. AS SYNOPTIC
WINDS SLOWLY VEER FROM 190-230 OVERNIGHT INTO WED...THE THREAT FOR
SEA FOG WILL SLOWLY DIMINISH OR ATLEAST KEEP THE FOG FROM ADVECTING
ONSHORE/INLAND. WILL INDICATE VSBY REDUCING TO 1NM OR LESS. IF ANY
RECEIVED REPORTS AND/OR OBS INDICATE 1/2 NM OR LESS VSBYS...WILL
THEN UPDATE AND ADVERTISE DENSE FOG. A MARINE WEATHER STATEMENT HAS
BEEN ISSUED TO HIGHLIGHT THE INCREASED POTENTIAL FOR SEA FOG.
HAVE MAINTAINED THE WINDS AND SEAS FORECAST FROM THE PREVIOUS
FORECAST...WITH THE LATEST HRRR KEEPING WINDS ON THE LOWER SIDE OF
MODEL GUIDANCE. WHICH IN TURN...PRODUCING SLIGHTLY LOWER SEAS THAN
ORIGINALLY THOUGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A COLD FRONT WILL BE APPROACHING THE WATERS
LATE WEDNESDAY INTO THURSDAY. SOUTHWEST WINDS WILL INCREASE
THROUGH OUT THE DAY ON WEDNESDAY AND THE LOCAL SWAN MODEL IS
INDICATING THE SEAS WILL REACH SMALL CRAFT CONDITIONS AROUND
MIDNIGHT WEDNESDAY NIGHT-THURSDAY MORNING. AS THE FRONT PUSHES
THROUGH THE COLD AIR ADVECTION WILL HELP PROVIDE AN ENVIRONMENT
FOR 20 TO 25 KNOT OFF SHORE WINDS ON THURSDAY.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...POST FRONT COLD SURGE IN THE 15 TO 20 KT RANGE
FRI WILL DROP CLOSER TO 10 KT BY SAT MORNING AS GRADIENT. WEAK
COASTAL TROF TAKING SHAPE WILL INDUCE A MORE EASTERLY COMPONENT TO
LOW LEVEL FLOW. GRADIENT REMAINS WEAK THROUGH THE END OF THE PERIOD
WITH WINDS BECOMING EAST TO SOUTHEAST LATE SAT NIGHT AND SUN AS
ELONGATED RIDGE AXIS SHIFTS OFFSHORE. ADVISORY WORTHY SEAS AT THE
START OF THE PERIOD WILL DROP TO 3 TO 4 FT BY FRI NIGHT AND REMAIN
IN THE 3 TO 4 FT RANGE THROUGH SUN.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HAWKINS
NEAR TERM...DOUGH
SHORT TERM...HAWKINS
LONG TERM...III
AVIATION...RJD/LACORTE
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1045 PM EST TUE NOV 15 2011
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OVER THE REGION THROUGH WEDNESDAY.
A COLD FRONT OVER THE MIDWEST WILL SLIDE EASTWARD BRINGING SHOWERS
AND A CHANCE OF THUNDERSTORMS OVERNIGHT WEDNESDAY INTO THURSDAY.
MUCH COOLER AND DRIER AIR WILL FOLLOW ON THURSDAY AND FRIDAY. HIGH
PRESSURE WILL MOVE OVERHEAD WITH TEMPERATURES MODERATING DURING THE
WEEKEND. A SECOND FRONT WILL SHIFT TOWARD THE AREA ON TUESDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1045 PM TUESDAY...SPORADIC ONSHORE MOVEMENT OF PATCHY OR AREAS
OF SEA FOG WILL CONTINUE OVERNIGHT. THIS A RESULT OF SFC WINDS
BOUNCING FROM 180-210 DEGREES. AS WINDS BECOME DOMINANT 210-230
DEGREE DIRECTION AFTER DAYBREAK WEDNESDAY...THE THREAT FOR SEA FOG
MOVING ONSHORE WILL DIMINISH GREATLY. SCATTERED -SHRA LATE THIS
EVENING AND OVERNIGHT DUE TO A WEAK LOW-MID LEVEL IMPULSE TRACKING
NE...AS WELL AS LOW LEVEL WINDSPEED CONVERGENCE FROM 15-25 KT S-SW
WINDS OFFSHORE QUICKLY DROPPING TO 10 KT OR LESS OVER THE COOLER
SHELF WATERS...AS WELL AS WEAK WIND DIRECTION CONVERGENCE FROM SW
INLAND TO S-SSW ALONG THE IMMEDIATE COAST.
AS FOR SEA FOG...THE LATEST AVAILABLE SST MAP OF THE WATERS OFF THE
SOUTHEAST U.S. COAST USING AVHRR DATA FOR THE 2 DAYS ENDING ON NOV
14TH...INDICATED 2 PATCHES OF NOTEWORTHY COOL SHELF WATERS OFF THE
CAROLINAS...WITH 1 PATCH BETWEEN SURF CITY AND CAPE FEAR...TO NEARLY
OUT TO THE FRYING PAN SHOALS BUOY...41013. AND THE SECOND PATCH
LYING ACROSS THE COASTAL WATERS BETWEEN NORTH MYRTLE BEACH TO SOUTH
SANTEE RIVER. THIS 2ND ONE NOT AS PRONOUNCED AS THE 1ST. WITH SFC
DEWPOINTS IN THE MID 60S TO NEAR 70 ADVECTING ACROSS THESE COOLER
SHELF WATERS OVERNIGHT INTO WED...SEA FOG WILL CONTINUE TO DEVELOP
AND AFFECT THE IMMEDIATE COAST BORDERING THE AFOREMENTIONED COLL
SHELF WATER AREAS. A FEW LOCAL SURF CAMS HAVE ALSO SHOWCASED THE
EXISTENCE OF THE SEA FOG AT TIMES.
PREVIOUS MIN FORECAST FOR TONIGHT STILL LOOKING AOK WITH ANY TWEAKS
NEEDED WOULD BE ON THE ORDER TO INCREASE LOWS CLOSER TO THE
IMMEDIATE COAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A LARGE SCALE UPPER LEVEL TROUGH OVER THE
WESTERN UNITED STATES WILL SHIFT EASTWARD BY WEDNESDAY NIGHT AND
THIS WILL PROVIDE GOOD SYNOPTIC LIFT FOR THE REGION. AT THE
SURFACE A FRONTAL BOUNDARY WILL ACT AS THE LOW LEVEL LIFTING
MECHANISM FOR SHOWERS AND ISOLATED THUNDERSTORMS. INSTABILITY IS
FORECAST BY THE MODEL TO BE VERY LOW AND THE LOW-LEVEL 0 TO 2.5 KM
BULK SHEAR MAGNITUDE REACHES ALMOST 40 KNOTS. THE LOW-LEVEL
HELICITY MAXIMUM APPEARS TO BE SHIFTING FARTHER NORTH WITH THIS
MODEL RUN AND IS RUNNING AHEAD OF THE MODEL CONVECTION...SO
CONFIDENCE ON ISOLATED TORNADOES IS NOT VERY HIGH AT THIS TIME.
MAXIMUM TEMPERATURES ARE EXPECTED TO REACH IN THE UPPER 70S INLAND
ON WEDNESDAY AND WITH THE FRONTAL BOUNDARY PASSAGE HIGHS ARE
EXPECTED TO ONLY REACH IN THE LOWER TO MIDDLE 60S ON THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...COLD SURFACE HIGH BUILDS INTO THE REGION FRI
BEFORE QUICKLY SHIFTING NORTHEAST FRI NIGHT INTO SAT. WEAK COASTAL
TROUGH DEVELOPS SAT WITH LOW LEVEL EAST TO NORTHEAST FLOW
INCREASING MOISTURE IN THE LOWEST 3K FT OR SO. CURRENT FORECAST IS
DEVOID OF PRECIP HOWEVER THE INCREASE IN LOW LEVEL MOISTURE
COMBINED WITH DEVELOPING RETURN FLOW JUST ABOVE THE SURFACE LATER
IN THE DAY SAT COULD PRODUCE SOME LIGHT PATCHY OF RAIN. WOULD NOT
EXPECT MUCH QPF SHOULD SOMETHING DEVELOP WITH COASTAL NC THE MOST
LIKELY AREA TO SEE SOMETHING. AT THE VERY LEAST ANTICIPATE AN
INCREASE IN CLOUD COVER SAT INTO SUN.
COASTAL TROUGH DISSIPATES SUN AS SURFACE RIDGE AXIS SHIFTS EAST OF
THE AREA. ALTHOUGH DEVELOPING SOUTHERLY FLOW HELPS INCREASE LOW
LEVEL MOISTURE SUN AND MON DRY MID LEVELS AND WEAK CAP...A RESULT OF
BUILDING WEAK MID LEVEL RIDGE...WILL PREVENT ANY PRECIP. WEAK COLD
FRONT STALLED NORTH OF THE AREA TUE WILL TRY AND DROP SOUTH DURING
THE DAY. IF FRONT MOVES ACROSS THE AREA DO NOT THINK IT WOULD HAVE
MUCH PRECIP ASSOCIATED WITH IT. THE FRONT IS STRETCHED OUT WITH THE
DYNAMICS WELL OFF TO THE NORTHEAST.
TEMPERATURES WILL RANGE FROM WELL BELOW CLIMO AT THE START OF THE
PERIOD TO ABOVE CLIMO EARLY NEXT WEEK. THE TRANSITION FROM BELOW
CLIMO TO ABOVE WILL BE QUICK...BY SAT NIGHT TEMPS SHOULD BE ABOVE
CLIMO.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...EXPECT CONTINUED AREAS OF PATCHY SEA FOG TO ADVECT
ONSHORE AT KCRE/KMYR OVER THE NEXT COUPLE OF HOURS...REDUCING
VSBYS OFF AND ON TO MVFR BEFORE FLOW FROM VEERING WINDS STEER FOG
AWAY FROM TERMINALS AFTER DAYBREAK. FOR KILM...CURRENT RADAR
DEPICTS SOME -SHRA OFFSHORE. CANNOT RULE OUT A LIGHT SHOWER TO
WRAP AROUND TO TERMINAL...AND POSSIBLY THE TWO OTHER COASTAL
SITES...THUS HAVE OPTED TO INCLUDE VCSH FOR A FEW HOURS.
ELSEWHERE...VFR WILL PREVAIL THROUGH ROUGHLY 06Z WITH SOUTH-
SOUTHWEST WINDS AROUND 5-8KTS. WITH MODELS IN GENERAL
AGREEMENT...ANTICIPATE CIGS AND VSBYS AT ALL SITES DETERIORATE
AFTER 07Z DUE TO ADVECTION FOG/STRATUS. FOR NOW...ANTICIPATE
LIFR/IFR CIGS...AND IFR/MVFR FOG THROUGH WEDNESDAY MORNING. SOON
AFTER DAYBREAK...EXPECT CONDITIONS TO SLOWLY IMPROVE TO VFR...WITH
TIGHTENED PRESSURE GRADIENT CREATING GUSTY WINDS 18-22KTS ACROSS
THE ENTIRE AREA. WINDS THROUGHOUT THE PERIOD WILL REMAIN SOUTH-
SOUTHWEST. TOWARDS THE END OF THE VALID PERIOD INTO THE
NEXT...CONDITIONS WILL SLOWLY BEGIN TO DETERIORATE AGAIN AS A COLD
FRONT BRINGS ANTICIPATED SHRA AND ISOLATED TSRA.
EXTENDED OUTLOOK...COLD FRONT MOVING ACROSS THE AREA WEDNESDAY
EVENING THROUGH THURSDAY MORNING COULD CREATE ISOLATED TSRA AND IFR.
EXPECT VFR FRIDAY AND SATURDAY...WITH LOWERED CONFIDENCE FOR
POTENTIAL IFR FOG/STRATUS SUNDAY MORNING.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 PM TUESDAY...THE SEA FOG THREAT CONTINUES ACROSS THE ILM
WATERS. WILL CONTINUE TO INDICATE PATCHY/AREAS OF SEA FOG ACROSS THE
ILM WATERS THROUGH OR JUST AFTER DAYBREAK WEDNESDAY. WITH THE LATEST
AVAILABLE SST MAP OF THE ILM WATERS USING AVHRR DATA FOR THE 2 DAYS
ENDING ON NOV 14TH...2 NOTEWORTHY PATCHES OF COOLER SHELF WATERS IN
THE LOW 60S WERE SHOWN. ONE PATCH BETWEEN SURF CITY AND CAPE
FEAR...AND OUT TO NEARLY THE FRYING PAN SHOALS BUOY...41013. AND THE
2ND PATCH...LYING ACROSS THE WATERS BETWEEN NORTH MYRTLE BEACH TO
SOUTH SANTEE RIVER. THIS 2ND ONE NOT NEARLY AS PRONOUNCED AS THE
1ST. SFC DEWPOINTS IN THE MID 60S TO NEAR 70 WILL CONTINUE TO ADVECT
ACROSS THESE COOLER SHELF WATERS OVERNIGHT INTO WED. THIS WILL
RESULT WITH AN INCREASED POTENTIAL FOR SEA FOG TO DEVELOP AND AFFECT
THE ILM WATERS...PARTICULAR ACROSS THOSE COOL WATERS. A FEW LOCAL
SURF CAMS HAVE SHOWCASED THE EXISTENCE OF THE SEA FOG. AS SYNOPTIC
WINDS SLOWLY VEER FROM 190-230 OVERNIGHT INTO WED...THE THREAT FOR
SEA FOG WILL SLOWLY DIMINISH OR ATLEAST KEEP THE FOG FROM ADVECTING
ONSHORE/INLAND. WILL INDICATE VSBY REDUCING TO 1NM OR LESS. IF ANY
RECEIVED REPORTS AND/OR OBS INDICATE 1/2 NM OR LESS VSBYS...WILL
THEN UPDATE AND ADVERTISE DENSE FOG. A MARINE WEATHER STATEMENT HAS
BEEN ISSUED TO HIGHLIGHT THE INCREASED POTENTIAL FOR SEA FOG.
HAVE MAINTAINED THE WINDS AND SEAS FORECAST FROM THE PREVIOUS
FORECAST...WITH THE LATEST HRRR KEEPING WINDS ON THE LOWER SIDE OF
MODEL GUIDANCE. WHICH IN TURN...PRODUCING SLIGHTLY LOWER SEAS THAN
ORIGINALLY THOUGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...A COLD FRONT WILL BE APPROACHING THE WATERS
LATE WEDNESDAY INTO THURSDAY. SOUTHWEST WINDS WILL INCREASE
THROUGH OUT THE DAY ON WEDNESDAY AND THE LOCAL SWAN MODEL IS
INDICATING THE SEAS WILL REACH SMALL CRAFT CONDITIONS AROUND
MIDNIGHT WEDNESDAY NIGHT-THURSDAY MORNING. AS THE FRONT PUSHES
THROUGH THE COLD AIR ADVECTION WILL HELP PROVIDE AN ENVIRONMENT
FOR 20 TO 25 KNOT OFF SHORE WINDS ON THURSDAY.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 PM TUESDAY...POST FRONT COLD SURGE IN THE 15 TO 20 KT RANGE
FRI WILL DROP CLOSER TO 10 KT BY SAT MORNING AS GRADIENT. WEAK
COASTAL TROF TAKING SHAPE WILL INDUCE A MORE EASTERLY COMPONENT TO
LOW LEVEL FLOW. GRADIENT REMAINS WEAK THROUGH THE END OF THE PERIOD
WITH WINDS BECOMING EAST TO SOUTHEAST LATE SAT NIGHT AND SUN AS
ELONGATED RIDGE AXIS SHIFTS OFFSHORE. ADVISORY WORTHY SEAS AT THE
START OF THE PERIOD WILL DROP TO 3 TO 4 FT BY FRI NIGHT AND REMAIN
IN THE 3 TO 4 FT RANGE THROUGH SUN.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HAWKINS
NEAR TERM...DOUGH
SHORT TERM...HAWKINS
LONG TERM...III
AVIATION...LACORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1013 PM EST THU NOV 17 2011
.SYNOPSIS...
WESTERLY WINDS WILL BRING LAKE EFFECT SNOWS TO THE SNOW BELT OF
NORTHWESTERN PENNSYLVANIA TONIGHT...BUT HIGH PRESSURE WILL BUILD IN
QUICKLY ON FRIDAY MORNING. THE HIGH WILL SET UP ALONG THE EAST COAST
FOR THIS WEEKEND. A WEAK COLD FRONT WILL LIKELY SAG SOUTHWARD
THROUGH THE AREA LATE SUNDAY. A DEVELOPING STORM SYSTEM IN THE
MISSISSIPPI VALLEY COULD AFFECT CENTRAL PA EITHER TUESDAY OR
WEDNESDAY OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
OOZ HRRR AND 02Z RUC CONFIRMS WHAT WE/RE SEEING ON THE REGIONAL
88D MOSAIC THIS EVENING...WHICH IS A RATHER FRAGMENTED OR CELLUAR
PATTERN TO THE LAKE EFFECT AND ORORGAPHIC SNOW SHOWERS THAT WILL
AFFECT THE NW MTNS OVERNIGHT...AND TO A MUCH LESSER DEGREE - THE
LAUREL HIGHLANDS.
COLDEST MID-LEVEL TEMPS /WITHIN THE 700-500 MB LAYER/ WILL BE
EXITING TO THE NE OF THE REGION OVERNIGHT...THOUGH THE THERMAL
TROUGH AT 850 MB /WITH MIN TEMPS AROUND -10C/ WILL BE CENTERED
ACROSS NRN AND WESTERN PENN THROUGH 12Z FRIDAY.
A FAIRLY WELL-ALIGNED BUT GRADUALLY VEERING WEST TO NW BOUNDARY
LAYER FLOW WILL MAINTAIN NUMEROUS /AND BRIEFLY MDT-HVY/ SNOW
SHOWERS ACROSS THE NW MTNS. ACCUMS NEAR...AND TO THE WEST OF KBFD
WILL NOT ENOUGH TO WARRANT A LES ADVISORY...AND WILL BE MAINLY
BETWEEN 1-2 INCHES OVER A 12-16 HOUR PERIOD. LOCALIZED 3 INCH
AMOUNTS ARE POSSIBLE NEAR AND TO THE WEST OF KBFD...MAINLY TO THE
NORTH OF ROUTE 6.
NARROW BANDS OF LIGHTER SNOW SHOWERS ACROSS THE LAURELS WILL
BRING A LIGHT COATING OF SNOW TO MANY LOCATIONS...WITH UP TO ONE
INCH POSSIBLE ON A FEW OF THE RIDGES WEST OF RT 219.
FOR THE SOUTHEAST TWO THIRDS OF THE REGION...EXPECT A FEW FLURRIES
AND PERHAPS A BRIEF 2-5 MINUTE SNOW SHOWER THROUGH THE OVERNIGHT.
MIN TEMPS TONIGHT /AROUND 20F ACROSS THE NW MTNS AND LAUREL
HIGHLANDS...AND IN THE MID TO UPPER 20S THROUGHOUT THE CENTRAL AND
SE VALLEYS/ WILL BE 5-6F BELOW NORMAL.
THE WIND STAYS GUSTY FOR MUCH OF THE NIGHT DUE TO TIGHT P-GRAD.
GUSTS BETWEEN 25-30 MPH WILL BE COMMON ACROSS THE CENTRAL AND WRN
ZONES. A FEW GUSTS NEAR SNOW SHOWERS COULD RANGE UP TO 35 MPH.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
8H TEMPS RISE 10C THROUGH THE DAYLIGHT HRS...AND PUSH ANY
REMAINING LAKE EFFECT SNOW WELL TO THE NORTH IN THE EARLY MORNING.
REST OF THE SHORT TERM SHOULD BE CLEAR. SFC TEMPS MIGHT ONLY
REBOUND ABOUT 15F WITH SHALLOW COLD AIR STUBBORN TO GO AWAY...ESP
IN THE EASTERN VALLEYS. SFC HIGH PASSES TO OUR SOUTH DURING THE
DAY AND SETS UP LIKE A BERMUDA HIGH. CLEAR SKIES AND THE STUBBORN
COOLER AIR IN THE EAST WILL HELP THE ERN COLD SPOTS LIKE SEG AND
THV DIP INTO THE L20S. M-U20S LOOK GOOD FOR MINS ELSEWHERE ESP THE
RIDGES WHERE SRLY WIND WILL KEEP GOING LIGHTLY FOR MUCH OF THE
NIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
BROAD SOUTHWESTERLY FLOW ALOFT CONTINUES TO BE FORECAST
BY THE LONG TERM MODELS THROUGH AT LEAST THE BEGINNING OF NEXT
WEEK. THIS WILL KEEP TEMPERATURES NEAR TO ABOVE NORMAL THROUGH MUCH
OF THE PERIOD...WITH NO SIGNIFICANT PERIODS OF ARCTIC CHILL IN SITE
AS WE NOW INCLUDE THANKSGIVING DAY IN THIS FORECAST PACKAGE.
SHORTWAVE ENERGY IS FORECAST TO MAKE ITS WAY EAST BY THE MIDDLE OF
NEXT WEEK COMPLICATING THE UPPER FLOW PATTERN.
AS THE UPPER TROUGH BUILDS OVER THE WESTERN U.S. INTO THE
WEEKEND...THE SOUTHEASTERN RIDGE SHOULD PUSH WARMER AIR INTO OUR
REGION BY SATURDAY. THE 850 HPA TEMPERATURES ARE PREDICTED TO BE
1SD ABOVE NORMAL LATE SATURDAY ACROSS THE NW PART OF THE
STATE...AND AREA- WIDE ON SUNDAY. ANOTHER COLD FRONT APPROACHES
WITH THE NEXT CHC FOR SHOWERS LATER SUNDAY INTO MONDAY. THIS FRONT
IS FORECAST TO STALL OVER THE MID ATLANTIC REGION...WITH THE
POTENTIAL FOR A WAVE OF LOW PRESSURE BRINGING MORE PCPN INTO THE
REGION NEXT TUE/WED...BUT THE DETAILS AT THIS POINT ARE ANYTHING
BUT CLEAR.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
UPPER LOW MOVES ACROSS STATE TONIGHT WITH HIGH PRESSURE MOVING IN
BEHIND FOR FRI. THIS WILL BRING SNOW SHOWERS OFF OF THE LAKES
THROUGH SUNRISE TO THE NW MTNS...INCLUDING VARIABLE IFR TO VFR
CONDITIONS AT KBFD THROUGH THE OVERNIGHT. ELSEWHERE...THE AIRMASS
IS QUITE DRY...SO EXTENT OF THE SNOW SHOWERS AND LOW CIGS WILL BE
LIMITED TO THE NORTHWEST PART OF THE STATE WITH VFR ELSEWHERE.
WINDS OF 10-15 MPH GUSTING TO 25 MPH WILL GRADUALLY DIMINISH THIS
EVENING.
PERIOD OF VFR CONDITIONS FRI MORNING THROUGH SAT NIGHT AS A SW
FLOW OF MILD AIR DEVELOPS ON THE BACK SIDE OF THE HIGH.
OUTLOOK...
FRI-SAT...VFR. NO SIG WX.
SUN...GENERALLY VFR. MVFR IN SHOWERS POSS LATE.
MON-TUE...MVFR TS/SHRA/CIGS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...LAMBERT
SHORT TERM...DANGELO
LONG TERM...FITZGERALD/GARTNER
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
412 PM EST WED NOV 16 2011
.SYNOPSIS...
A COMPLICATED FRONTAL SYSTEM WILL FINALLY BE MOVING TO THE EAST
TONIGHT AND COLD AIR WILL RETURN FOR A COUPLE OF DAYS. MINOR LAKE
EFFECT SNOW IS EXPECTED IN THE SNOW BELT...THEN HIGH PRESSURE WILL
SETTLE IN FOR THE WEEKEND. THE HIGH WILL SET UP ALONG THE EAST
COAST BY EARLY NEXT WEEK. A WET BUT MILD PATTERN WILL THEN RETURN.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
DEW POINT IN KERI ALREADY INTO THE 30S...AND COLDER AIR ON THE WAY.
WINDS NOW MAINLY NW OVER WRN PA. HRRR AND CURR RADAR TRENDS
INDICATE THAT THERE IS A LIGHTER PATCH IN THE NEARLY CONSTANT RAIN
SHIELD HEADING FOR THE LOWER SUSQ. THE DRIER AIR THAT HAS BEEN
PULLED IN FROM THE SRN PLAINS AND THE CONSOLIDATION OF THE COLD
FRONT AND WARMER/STATIONARY BOUNDARY TO OUR SOUTH IS STARTING TO
WRAP THE SYSTEM UP A BIT AS IT PULLS NORTHEAST. PSEUDO DEFORMATION
AREA RAIN OVER CENTRAL PA BACK TO ERN KY IS DIMINISHING AT THE
SAME TIME...BUT CONTINUES TO SLIDE EASTWARD. WILL KEEP HIGH POPS
IN FOR THE EVENING BUT TAPER THEM OFF RATHER QUICKLY AND BY 10
PM...ALL BUT THE FAR SE SHOULD BE DRY. TEMPS DROP BELOW FREEZING
IN THE NW JUST AFTER MIDNIGHT. CLOUDS COULD HANG ON A LONG TIME
IN THE WEST...THOUGH...AS WRLY UPSLOPE FLOW PRODUCES LIFT. AS IT
GETS COLDER A FEW SHSN WILL PROBABLY DEVELOP OVER THE LAURELS/WRN
HIGHLANDS. DO NOT EXPECT ANY MORE THAN A DUSTING TONIGHT WITH
LITTLE MOISTURE AND SUBSIDENCE BATTLING THE LLVL UPSLOPE. MINS
SHOULD HOLD IN THE 40S IN THE SE HALF OF THE AREA. THERE IS A
TRICKY PART TO THE FORECAST THAT STARTS TONIGHT...BUT LASTS INTO
THE NEXT PD.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE FORECAST PROBLEM IS WHETHER A SECONDARY WAVE ON THE OLD FRONT
DEVELOPS SOON ENOUGH AND CLOSE ENOUGH TO THE LOCAL AREA /BUT TO
THE SOUTH/ TO PRODUCE LIGHT PCPN BACK INTO THE COOLING AIR OVER
THE REGION...ESP THE SE. THE WAVE HAS BEEN HINTED AT FOR A FEW
DAYS NOW...SO CONFIDENCE HAS INCREASED SLIGHTLY...BUT THE CUTOFF
OF ANY PRECIP LOOKS RATHER SHARP. IT LOOKS LIKE MOST OF THE
POSSIBLE PCPN WOULD STAY TO THE S/E OF THE AREA BUT MAKES A CLOSE
PASS. BUFKIT SOUNDINGS FROM NAM DO LOOK PLENTY COLD FOR
SNOW...BUT IT WOULD BE FALLING INTO UBER-FREEZING AIR AND DURING
THE DAYLIGHT HOURS. WILL CALL IT A CHC OF RAIN/SNOW SHOWERS FOR
NOW IN THE FAR LWR SUSQ AS IT IS WORTH A MENTION AT THIS POINT.
TEMPS HARDLY MOVE ON THURS UNDER COLD ADVECTION.
AN EASIER PART TO THE FCST IN THE SHORT TERM IS THAT WE WILL
DOUBTLESSLY SEE LAKE EFFECT CLOUDS/FLURRIES IN THE WEST...AND
ACCUMS IN THE SNOW BELT OF WARREN CO. POTTER AND MCKEAN COULD ALSO
PICK UP AN INCH OR SO THURSDAY INTO THURS NIGHT. THE AXIS OF THE
UPPER TROUGH CROSSES LAKE ERIE MID-DAY THURSDAY AND SHOULD DRIVE
THE HEAVIEST SNOWS INLAND DURING THE LATE DAY AND INTO THE
OVERNIGHT. DURATION OF THE BEST BANDS WOULD PROBABLY BE ONLY UNTIL
FRIDAY MORNING...AS 8H THERMAL TROUGH OF -12C AIR PASSES BY 12Z
FRI. LOCAL PROGRAM GIVES BAND OF AROUND 80 MI EVEN WITH THE
FAVORABLE 280-290 FETCH AND DEEP 10KFT INVERSION. WIND SPEEDS ARE
ONLY 30KTS...BUT ARE WELL-ALIGNED VERTICALLY. STORM TOTALS MIGHT
GET INTO THE 3-4 INCH RANGE OVER 18-20 HRS. THIS IS NOT QUITE
WORTH AN ADVY YET...ESP SINCE IT IS A LATE 2ND/3RD PD EVENT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
UPPER TROF EXITING THE EASTERN U.S. AT THE START OF THE PERIOD WILL
TRANSITION TO BROAD SOUTHWESTERLY FLOW WHICH IS THEN FORECAST TO
DOMINATE MUCH OF THE LONG TERM PERIOD. FLOW IS FORECAST TO TURN
MORE WESTERLY BY THE END OF THE PERIOD AS ENERGY OVER THE WESTERN
U.S. WORKS ITS WAY EAST.
AS THE UPPER TROUGH BUILDS OVER THE WESTERN US LATER THIS
WEEK...THE SOUTHEASTERN RIDGE SHOULD PUSH WARMER AIR INTO OUR
REGION SATURDAY. THE 850 HPA TEMPERATURES ARE PREDICTED TO BE 1SD
ABOVE NORMAL LATE SATURDAY ACROSS THE NW PART OF THE STATE...AND
AREA- WIDE ON SUNDAY. ANOTHER COLD FRONT APPROACHES WITH THE NEXT
CHC FOR SHOWERS LATER SUNDAY INTO MONDAY. THIS FRONT IS FORECAST
TO STALL OVER THE MID ATLANTIC REGION...WITH THE POTENTIAL FOR
WAVES OF LOW PRESSURE TO BRING MORE PCPN INTO THE REGION NEXT
MONDAY INTO TUE...BUT THE DETAILS AT THIS POINT ARE ANYTHING BUT CLEAR.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
LOW CIGS STARTING TO LIFT AS THE COLDER AND DRIER AIR UNDERCUTS THE
MOISTURE WHICH IS GETTING CUT OFF FROM THE GOMEX ALREADY.
IMPROVEMENT MAY BE SLOW IN KJST WITH WINDS WNW IN A GOOD UPSLOPE
ORIENTATION. SHSN MAY START IN KJST TONIGHT...BUT WILL KEEP FCST
BETTER THAN VFR FOR NOW. RAIN SHIELD SHOULD GRADUALLY SHRINK AND
SLIDE TO THE EAST PER TRENDS IN RADAR MOSAIC AND MESO MDLS. SLOW
MOVEMENT TO THE SFC TROUGH TO THE SE WILL KEEP LIGHT RAIN GOING
FOR MOST OF THE EVENING IN THE SE. LITTLE/NO PRECIP EXPECTED
OVERNIGHT...BUT A SECONDARY WAVE MAY DEVELOP TONIGHT TO OUR SOUTH
AND THROW SOME COLDER PRECIP BACK IN FROM THE SE. LOW POSS AT THIS
POINT...AND AT THE OUTER REACHES OF THIS 18Z 24HR TAF PD...BUT
SOMETHING TO WATCH FOR ON THURS. UPSLOPE IN THE WEST AND OFF LAKE
ERIE WILL GENERATE LAKE EFFECT THURS AFTN INTO FRI AM VCTY KBFD.
OUTLOOK...
FRI-SAT...VFR. NO SIG WX.
SUN...GENERALLY VFR. MVFR POSS LATE.
MON...MVFR TS/SHRA/CIGS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
258 PM EST WED NOV 16 2011
.SYNOPSIS...
A COMPLICATED FRONTAL SYSTEM WILL FINALLY BE MOVING TO THE EAST
TONIGHT AND COLD AIR WILL RETURN FOR A COUPLE OF DAYS. MINOR LAKE
EFFECT SNOW IS EXPECTED IN THE SNOW BELT...THEN HIGH PRESSURE WILL
SETTLE IN FOR THE WEEKEND. THE HIGH WILL SET UP ALONG THE EAST
COAST BY EARLY NEXT WEEK. A WET BUT MILD PATTERN WILL THEN RETURN.
&&
.NEAR TERM /THROUGH TONIGHT/...
DEW POINT IN KERI ALREADY INTO THE 30S...AND COLDER AIR ON THE WAY.
WINDS NOW MAINLY NW OVER WRN PA. HRRR AND CURR RADAR TRENDS
INDICATE THAT THERE IS A LIGHTER PATCH IN THE NEARLY CONSTANT RAIN
SHIELD HEADING FOR THE LOWER SUSQ. THE DRIER AIR THAT HAS BEEN
PULLED IN FROM THE SRN PLAINS AND THE CONSOLIDATION OF THE COLD
FRONT AND WARMER/STATIONARY BOUNDARY TO OUR SOUTH IS STARTING TO
WRAP THE SYSTEM UP A BIT AS IT PULLS NORTHEAST. PSEUDO DEFORMATION
AREA RAIN OVER CENTRAL PA BACK TO ERN KY IS DIMINISHING AT THE
SAME TIME...BUT CONTINUES TO SLIDE EASTWARD. WILL KEEP HIGH POPS
IN FOR THE EVENING BUT TAPER THEM OFF RATHER QUICKLY AND BY 10
PM...ALL BUT THE FAR SE SHOULD BE DRY. TEMPS DROP BELOW FREEZING
IN THE NW JUST AFTER MIDNIGHT. CLOUDS COULD HANG ON A LONG TIME
IN THE WEST...THOUGH...AS WRLY UPSLOPE FLOW PRODUCES LIFT. AS IT
GETS COLDER A FEW SHSN WILL PROBABLY DEVELOP OVER THE LAURELS/WRN
HIGHLANDS. DO NOT EXPECT ANY MORE THAN A DUSTING TONIGHT WITH
LITTLE MOISTURE AND SUBSIDENCE BATTLING THE LLVL UPSLOPE. MINS
SHOULD HOLD IN THE 40S IN THE SE HALF OF THE AREA. THERE IS A
TRICKY PART TO THE FORECAST THAT STARTS TONIGHT...BUT LASTS INTO
THE NEXT PD.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
THE FORECAST PROBLEM IS WHETHER A SECONDARY WAVE ON THE OLD FRONT
DEVELOPS SOON ENOUGH AND CLOSE ENOUGH TO THE LOCAL AREA /BUT TO
THE SOUTH/ TO PRODUCE LIGHT PCPN BACK INTO THE COOLING AIR OVER
THE REGION...ESP THE SE. THE WAVE HAS BEEN HINTED AT FOR A FEW
DAYS NOW...SO CONFIDENCE HAS INCREASED SLIGHTLY...BUT THE CUTOFF
OF ANY PRECIP LOOKS RATHER SHARP. IT LOOKS LIKE MOST OF THE
POSSIBLE PCPN WOULD STAY TO THE S/E OF THE AREA BUT MAKES A CLOSE
PASS. BUFKIT SOUNDINGS FROM NAM DO LOOK PLENTY COLD FOR
SNOW...BUT IT WOULD BE FALLING INTO UBER-FREEZING AIR AND DURING
THE DAYLIGHT HOURS. WILL CALL IT A CHC OF RAIN/SNOW SHOWERS FOR
NOW IN THE FAR LWR SUSQ AS IT IS WORTH A MENTION AT THIS POINT.
TEMPS HARDLY MOVE ON THURS UNDER COLD ADVECTION.
AN EASIER PART TO THE FCST IN THE SHORT TERM IS THAT WE WILL
DOUBTLESSLY SEE LAKE EFFECT CLOUDS/FLURRIES IN THE WEST...AND
ACCUMS IN THE SNOW BELT OF WARREN CO. POTTER AND MCKEAN COULD ALSO
PICK UP AN INCH OR SO THURSDAY INTO THURS NIGHT. THE AXIS OF THE
UPPER TROUGH CROSSES LAKE ERIE MID-DAY THURSDAY AND SHOULD DRIVE
THE HEAVIEST SNOWS INLAND DURING THE LATE DAY AND INTO THE
OVERNIGHT. DURATION OF THE BEST BANDS WOULD PROBABLY BE ONLY UNTIL
FRIDAY MORNING...AS 8H THERMAL TROUGH OF -12C AIR PASSES BY 12Z
FRI. LOCAL PROGRAM GIVES BAND OF AROUND 80 MI EVEN WITH THE
FAVORABLE 280-290 FETCH AND DEEP 10KFT INVERSION. WIND SPEEDS ARE
ONLY 30KTS...BUT ARE WELL-ALIGNED VERTICALLY. STORM TOTALS MIGHT
GET INTO THE 3-4 INCH RANGE OVER 18-20 HRS. THIS IS NOT QUITE
WORTH AN ADVY YET...ESP SINCE IT IS A LATE 2ND/3RD PD EVENT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
SOUTHWESTERLY FLOW ALOFT WILL DOMINATE MUCH OF THE LONG TERM
PERIOD AS UPPER LOW SETS OVER CENTRAL CANADA AND UPPER RIDGING
STRETCHES OVER THE WRN ATLANTIC AND EASTERN CARIBBEAN. ONE UPPER
TROF MOVES THROUGH THE NORTHEAST THURSDAY INTO FRIDAY...THEN A
SERIES OF WAVE MOVE THROUGH LATE IN THE PERIOD TURNING THE FLOW
MORE ZONAL EARLY NEXT WEEK. TEMPERATURES MODERATE BACK TOWARD
NORMAL FRIDAY.
AS THE UPPER TROUGH BUILDS OVER THE WESTERN US LATER THIS
WEEK...THE SOUTHEASTERN RIDGE SHOULD PUSH WARMER AIR INTO OUR
REGION SATURDAY. THE 850 HPA TEMPERATURES ARE PREDICTED TO BE 1SD
ABOVE NORMAL LATE SATURDAY ACROSS THE NW PART OF THE STATE...AND
AREA- WIDE ON SUNDAY. ANOTHER COLD FRONT APPROACHES WITH THE NEXT
CHC FOR SHOWERS LATER SUNDAY INTO MONDAY. THIS FRONT IS FORECAST
TO STALL OVER THE MID ATLANTIC REGION...WITH THE POTENTIAL FOR
WAVES OF LOW PRESSURE TO BRING MORE PCPN INTO THE REGION NEXT
MONDAY INTO TUE...BUT THE DETAILS AT THIS POINT ARE ANYTHING BUT CLEAR.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
LOW CIGS STRTING TO LIFT AS THE COLDER AND DRIER AIR UNDERCUTS THE
MOISTURE WHICH IS GETTING CUT OFF FROM THE GOMEX ALREADY.
IMPROVEMENT MAY BE SLOW IN KJST WITH WINDS WNW IN A GOOD UPSLOPE
ORIENTATION. SHSN MAY START IN KJST TONIGHT...BUT WILL KEEP FCST
BETTER THAN VFR FOR NOW. RAIN SHIELD SHOULD GRADUALLY SHRINK AND
SLIDE TO THE EAST PER TRENDS IN RADAR MOSAIC AND MESO MDLS. SLOW
MOVEMENT TO THE SFC TROUGH TO THE SE WILL KEEP LIGHT RAIN GOING
FOR MOST OF THE EVENING IN THE SE. LITTLE/NO PRECIP EXPECTED
OVERNIGHT...BUT A SECONDARY WAVE MAY DEVELOP TONIGHT TO OUR SOUTH
AND THROW SOME COLDER PRECIP BACK IN FROM THE SE. LOW POSS AT THIS
POINT...AND AT THE OUTER REACHES OF THIS 18Z 24HR TAF PD...BUT
SOMETHING TO WATCH FOR ON THURS. UPSLOPE IN THE WEST AND OFF LAKE
ERIE WILL GENERATE LAKE EFFECT THURS AFTN INTO FRI AM VCTY KBFD.
OUTLOOK...
FRI-SAT...VFR. NO SIG WX.
SUN...GENERALLY VFR. MVFR POSS LATE.
MON...MVFR TS/SHRA/CIGS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...DEVOIR/GARTNER
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1150 PM EST THU NOV 17 2011
LATEST UPDATE...AVIATION...
.SYNOPSIS...(315 PM EST THU NOV 17 2011)
THE LAKE EFFECT SNOW SHOWERS WILL GRADUALLY DIMINISH THIS EVENING.
HIGH PRESSURE OVER THE MIDDLE MISSISSIPPI VALLEY WILL STRENGTHEN AS
IT BUILDS EAST INTO THE CENTRAL APPALACHIANS ON FRIDAY. A GUSTY
SOUTHWESTERLY FLOW WILL SETUP HERE IN LOWER MICHIGAN DURING THE DAY
AND PERSIST INTO SATURDAY. A COLD FRONT WILL SLIP SOUTHEASTWARD
THROUGH THE REGION SATURDAY NIGHT PRODUCING SOME RAIN SHOWERS.
COOLER AIR WILL THEN FILTER IN FOR THE REMAINDER OF THE WEEKEND.
&&
.SHORT TERM...(315 PM EST THU NOV 17 2011)
(TONIGHT THROUGH SATURDAY NIGHT)...
THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE WIND GUSTS ON
FRIDAY.
BUFKIT OVERVIEWS SHOW MIXING HEIGHTS TAPPING INTO THE 40
KNOT WIND RANGE ALONG THE LAKESHORE DURING THE DAY ON FRIDAY. ALSO
FSL RUC DATA SUGGESTS WINDS OVER 40 KNOTS MOVING INLAND DURING THE
DAY. PROFILER DATA FROM THE LOWER PLAINS SHOWS THE LOW
LEVEL JET FORMING AND IT IS ALREADY ABOUT 10 KNOTS STRONGER THAN
FORECASTED. WILL ISSUE A WIND ADVISORY FOR FRIDAY FROM 12Z TO 00Z.
MIXING HEIGHTS LOWER DURING THE EVENING AND THAT SHOULD ALLOW FOR
THE WIND TO DECREASE.
THE TIMING OF THE SHOWERS LATER SATURDAY INTO SATURDAY LOOKS GOOD.
I DID DELAY THE SHOWERS SLIGHTLY GIVEN THE SOMEWHAT SLOWER TREND OF
THE FRONTAL PASSAGE. AS A RESULT I TOOK OUT THE MENTION OF SHOWERS
PRIOR TO 18Z SAT.
A DECENT WARMUP IS IN STORE FOR THE REGION ON SATURDAY. LOW LEVEL
THERMAL PROFILES SUPPORT HIGHS TOPPING 50 DEGREES.
&&
.LONG TERM...(315 PM EST THU NOV 17 2011)
(SUNDAY THROUGH THANKSGIVING DAY)
THE LONG TERM PORTION OF THE FCST LOOKS RATHER TRANQUIL...ESPECIALLY
BY MID-LATE NOVEMBER STANDARDS FOR MICHIGAN. WE WILL HAVE TO WATCH A
POSSIBLE SYSTEM THAT COULD STILL IMPACT AT LEAST A PORTION OF THE
AREA TUE INTO TUE NIGHT.
FRONTAL SYSTEM MOVING THROUGH SAT/SAT NIGHT STILL APPEARS TO JUST
CLEAR THE CWFA BY 12Z SUN. DRY NE FLOW AROUND THE INCOMING SFC RIDGE
AND NOT SO COLD TEMPS /H850 TEMPS 0 TO -2C/ WILL BRING QUIET AND
SEASONABLE TEMPS TO THE AREA. WE ARE EXPECTING THIS HIGH TO RULE
ACROSS THE AREA AT LEAST THROUGH MON. FOR NOW...WE ARE DISCOUNTING
THE 12Z GFS BRINGING LIGHT PCPN TO THE AREA. IT SEEMS TO BE TRYING
TO PHASE SRN STREAM MOISTURE WITH A WEAK NRN STREAM TROUGH. THE
SETUP LOOKS OVERDONE WITH MOISTURE THIS FAR NORTH AND NOT FAVORABLE
FOR PCPN ON MON FOR NOW.
THE TRENDS IN THE MODELS ARE TO HAVE THE SYSTEM FOR TUE/WED A LITTLE
FURTHER NORTH THAN WAS EXPECTED 24 HOURS AGO. WE CAN NOT DISCOUNT
THIS IDEA EXPECTING IT MAY BE A LITTLE STRONGER THAN WHAT IS BEING
SAMPLED NOW. HOWEVER UNLESS THERE IS GOOD PHASING BETWEEN THE TWO
STREAMS...IT SHOULD CONTINUE TO MAINLY MISS THE AREA. THE 00Z EURO
WAS QUITE THE OUTLIER WITH A CLOSED NRN STREAM LOW PHASING WITH THE
SRN STREAM...AND BRINGING A LOT OF PCPN TO THE AREA TUE/WED. THE NEW
EURO HAS BACKED AWAY FROM THAT THINKING...AND IS CLOSER TO THE
ENSEMBLES. IN COORDINATION WITH SURROUNDING OFFICES...WE HAVE ADDED
A SMALL CHC OF PCPN TUE AND TUE NIGHT DOWN SOUTH FOR NOW...AND WILL
CONTINUE TO MONITOR THE TRENDS.
ALL OF THE MODELS HAVE A FAIRLY GOOD RIDGE THEN BUILDING OVER THE
AREA FOR WED AND THANKSGIVING DAY AS ANOTHER STRONG TROUGH TAKES
SHAPE ALONG THE WEST COAST. THIS SHOULD ALLOW FOR MORE SEASONABLE TO
SLIGHTLY ABOVE AVERAGE TEMPS FOR NOVEMBER ALONG WITH DRY CONDITIONS
FOR THE FIRST PART OF THE HOLIDAY TRAVEL PERIOD FOR MICHIGAN.
&&
.AVIATION...(1150 PM EST THU NOV 17 2011)
VFR CONDITIONS THROUGH FRIDAY EVENING...BUT STRONG WINDS WILL AFFECT
AVIATION. WINDS WILL GO SOUTHWEST THEN SOUTH ON FRIDAY MORNING AND
INCREASE TO NEAR 20 KNOTS WITH GUSTS OVER 30 KNOTS BY 18Z FRIDAY.
SOME GUSTS TO 40 KNOTS ARE POSSIBLE. THESE STRONG WINDS WILL
CONTINUE INTO FRIDAY EVENING THEN DIMINISH OVERNIGHT.
&&
.MARINE...(315 PM EST THU NOV 17 2011)
THE ARRIVAL OF A LOW LEVEL JET COUPLED WITH INCREASED MIXING ON
FRIDAY SUPPORTS KEEPING THE GALE WARNING FOR FRIDAY. MIXING
HEIGHTS SUGGEST THE NEARSHORE ZONES WILL REACH INTO THE 40 KNOT
RANGE OF WINDS FRIDAY. THE LOW LEVEL JET AND INCREASED MIXING
PERSISTS THROUGH 00Z SAT...THUS I WILL KEEP THE WARNING GOING
THROUGH MUCH OF THE NIGHT.
&&
.HYDROLOGY...(315 PM EST WED NOV 16 2011)
ANY QPF THROUGH THE PERIOD IS FORECASTED TO BE RELATIVELY LIGHT. AS
A RESULT... NO HYDRO ISSUES ANTICIPATED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY FOR THE LAKESHORE COUNTIES FRIDAY.
LM...SMALL CRAFT ADVISORY ALL NEARSHORE ZONES THROUGH TONIGHT.
GALE WARNING FRIDAY INTO FRIDAY NIGHT ALL NEARSHORE ZONES.
&&
$$
SYNOPSIS: MJS
SHORT TERM: MJS
LONG TERM: NJJ
AVIATION: OSTUNO
MARINE: MJS
HYDROLOGY: MJS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
348 AM EST FRI NOV 18 2011
.SYNOPSIS...
A CHILLY AIRMASS WILL REMAIN IN PLACE TODAY WITH LAKE EFFECT SNOW
EAST OF THE LAKES GRADUALLY ENDING. OUTSIDE OF LAKE EFFECT IT WILL
BE PARTLY SUNNY AND BREEZY. DRY CONDITIONS WILL LAST INTO SATURDAY
WITH HIGH PRESSURE NEARBY OVER THE EASTERN SEABOARD. A SOUTHWEST
FLOW OF WARMER AIR WILL BRING A QUICK REBOUND IN TEMPERATURES AS
THEY RECOVER TO A LITTLE ABOVE AVERAGE FOR THE WEEKEND. A COLD FRONT
WILL BRING A CHANCE OF A FEW LIGHT SHOWERS ON SUNDAY AND WILL USHER
IN COOLER AND SEASONABLE TEMPERATURES FOR THE START OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MAIN CONCERN THROUGH THIS MORNING CONTINUES TO REVOLVE AROUND LAKE
EFFECT.
OFF LAKE ERIE...JUST A LARGE AREA OF VERY LIGHT FLURRIES REMAINS
EARLY THIS MORNING ACROSS MUCH OF THE WESTERN SOUTHERN TIER. LATEST
HIGH RESOLUTION HRRR MODEL RUN SUGGESTS WE MAY SEE A VERY MODEST
INCREASE IN SNOW SHOWERS FROM 12Z-15Z ACROSS THE SOUTHERN TIER AND
PORTIONS OF SOUTHERN ERIE AND WYOMING COUNTIES. THIS APPEARS TO HAVE
SOME VALIDITY WITH IR SATELLITE STILL SHOWING PLENTY OF LAKE EFFECT
CLOUDS ALL THE WAY WEST TO CLEVELAND...AND WITH BOUNDARY LAYER FLOW
BACKING TO THE WSW THIS MORNING FETCH WILL INCREASE. STILL...EXPECT
NOTHING MORE THAN FLURRIES AND SCATTERED SNOW SHOWERS WITH ANY
ADDITIONAL ACCUMULATION LESS THAN AN INCH. THIS ACTIVITY SHOULD END
COMPLETELY BY LATE MORNING AS INVERSION HEIGHTS CRASH AND DRY AIR
BECOMES TOO DIFFICULT TO OVERCOME.
OFF LAKE ONTARIO...AN IMPRESSIVE PLUME AT 0830Z EXTENDS INTO MUCH OF
OSWEGO COUNTY WITH THE BEST ORGANIZATION WE HAVE SEEN ALL NIGHT. IR
SATELLITE TELLS THE STORY WITH THIS BURST OF INTENSITY CORRESPONDING
TO THE PASSAGE OF A BLOB OF DEEPER MOISTURE WITH ROOTS ACROSS THE
UPPER GREAT LAKES. IR SATELLITE IMAGERY CONTINUES TO SHOW AN
UPSTREAM CONNECTION TO GEORGIAN BAY...AND THIS SHOULD PRODUCE SOME
NICE SNOWFALL RATES ACROSS OSWEGO COUNTY THROUGH EARLY TO MID
MORNING WITH OCCASIONAL 1-2 INCH PER HOUR BURSTS. BY DAYBREAK EXPECT
THE MAIN FOCUS OF THIS BAND TO BE ACROSS THE NORTHERN HALF OF OSWEGO
COUNTY EXTENDING INTO THE SOUTHWEST CORNER OF LEWIS COUNTY NEAR
OSCEOLA. THIS LAST GASP HOLDS PROMISE TO GET SNOWFALL AMOUNTS UP TO
WARNING CRITERIA...WITH ANOTHER 2-4 INCHES THROUGH LATE MORNING
BRINGING STORM TOTALS TO 6-9 INCHES IN THE MOST PERSISTENT BANDS.
BY MID TO LATE MORNING THE BOUNDARY LAYER FLOW WILL BEGIN TO BACK
MORE WSW...WHICH WILL CARRY THE LAKE BAND NORTH ACROSS THE TUG HILL
AND SOUTHERN JEFFERSON COUNTY. AT THE SAME TIME...INVERSION HEIGHTS
WILL BE COMING DOWN AND MOISTURE DECREASING...SO EXPECT A RAPID
WEAKENING TREND AFTER ABOUT 15Z. THE BAND SHOULD DISSIPATE
ALTOGETHER BY EARLY AFTERNOON AS THE CRASHING INVERSION AND
DECREASING MOISTURE BECOME TOO MUCH TO OVERCOME.
OTHERWISE AREAS OUTSIDE OF LAKE EFFECT WILL SEE PLENTY OF SUNSHINE
TODAY...AND EVEN LAKE EFFECT AREAS SHOULD SEE SOME SUNSHINE THIS
AFTERNOON AFTER THE LAKE CLOUDS BEGIN TO DISSIPATE. STEADY WARM AIR
ADVECTION WILL BEGIN...BUT WILL BE TOO LATE TO BOOST TEMPS MUCH WITH
THE LOWER ELEVATIONS REACHING THE LOWER 40S WITH MID TO UPPER 30S
ACROSS HIGHER TERRAIN. A BRISK WIND WILL KEEP A WIND CHILL IN THE
AIR AS WELL.
TONIGHT HIGH PRESSURE WILL BUILD ACROSS THE MID ATLANTIC STATES. THE
SOUTHWEST RETURN FLOW WILL INCREASE ACROSS THE LOWER LAKES ON THE
WESTERN PERIPHERY OF THIS HIGH...WITH STEADY WARM AIR ADVECTION. ON
THE LAKE PLAINS BOUNDARY LAYER WINDS WILL REMAIN MIXED...WHICH WILL
ALLOW FOR STEADY OR SLOWLY RISING TEMPS AFTER EVENING LOWS IN THE
30S. SOME OF THE MORE SHELTERED INLAND VALLEYS WILL STILL BE ABLE TO
PARTIALLY DECOUPLE AND DROP OFF INTO THE 20S ONCE AGAIN. EXPECT A
FEW PERIODS OF MID/HIGH CLOUD COVER WITH MOST AREAS PARTLY CLOUDY
OVERNIGHT...EXCEPT FOR THE NORTH COUNTRY WHERE THICKER MID LEVEL
CLOUD ALONG THE RETREATING WARM FRONT MAY END UP PRODUCING A MOSTLY
CLOUDY NIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
HIGH PRESSURE CENTERED OFF THE ATLANTIC COAST WILL BRING DRY WEATHER
ON SATURDAY. WARM AIR ADVECTION ASSOCIATED WITH A POTENT LOW LEVEL
JET WILL BRING AN INCREASE IN MID LEVEL CLOUDS DURING THE
AFTERNOON...ESPECIALLY FOR AREAS NEAR LAKE ONTARIO. BUT...RELATIVELY
DRY AIR IN THE LOWER LEVELS SHOULD PRECLUDE THE DEVELOPMENT OF ANY
RAIN SHOWERS. AFTERNOON TEMPERATURES WILL HOVER AROUND 50...BUT A
MODEST SOUTHERLY FLOW WILL PUT A CHILL IN THE AIR. THE LATEST BUFKIT
TEMPERATURE PROFILES SUGGESTS THAT THE PRESENCE OF A LOW LEVEL
INVERSION SHOULD PREVENT THE TRANSFER OF HIGHER WINDS ALOFT
(ASSOCIATED WITH THE LOW LEVEL JET) DOWN TO THE SURFACE.
LOW PRESSURE THAT WILL BE MOVING OUT OF THE CENTRAL PLAINS SATURDAY
AFTERNOON IS FORECAST TO LIFT NORTH OF THE CENTRAL GREAT LAKES
SATURDAY NIGHT...THEN TRACK ACROSS SOUTHERN QUEBEC SUNDAY. ANOTHER
LOW LEVEL JET ADVANCING AHEAD OF THE SURFACE LOW WILL ADVECT
INCREASING LOW LEVEL MOISTURE ACROSS THE CWA SATURDAY NIGHT. THIS
WILL ALLOW SCATTERED RAIN SHOWERS TO SPREAD EAST ACROSS THE AREA
OVERNIGHT. A COLD FRONT TRAILING SOUTH OF THE SURFACE LOW WILL CROSS
WESTERN AND CENTRAL NEW YORK SUNDAY AFTERNOON. A FEW MORE RAIN
SHOWERS WILL ACCOMPANY THE FRONTAL PASSAGE...BUT AVAILABLE MOISTURE
WILL BE RATHER LIMITED...SO QPF SHOULD REMAIN UNDER A TENTH OF AN
INCH.
THE PROJECTED PATH OF THE LOW COULD RESULT IN RATHER WINDY
CONDITIONS ON SUNDAY...ESPECIALLY IF THE NAM`S TREND OF A
LOWER SURFACE PRESSURE VERIFIES. THE NAM AND GFS ALSO SHOWS FAIRLY
IMPRESSIVE ISALLOBARIC PRESSURE RISES SETTING UP JUST TO OUR
NORTHWEST DURING THE AFTERNOON AS COLDER AIR ADVECTS IN BEHIND THE
FRONT. BASED ON THESE TRENDS...WIND GUSTS MAY APPROACH ADVISORY
CRITERIA ON SUNDAY ACROSS THE NIAGARA FRONTIER AND LOWER GENESEE
VALLEY.
HIGH PRESSURE BUILDING IN BEHIND THE DEPARTED COLD FRONT WILL BRING
DRY CONDITIONS SUNDAY NIGHT ALONG WITH DIMINISHING WINDS. LAKE
EFFECT PCPN BEHIND THE FRONT IS NOT EXPECTED TO BE AN ISSUE AT THIS
TIME AS LOW LEVEL MOISTURE WILL BE LIMITED AND THERE WILL BE PLENTY
OF DIRECTIONAL SHEAR.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
UNCERTAINTY CREEPS INTO THE FORECAST BY MONDAY AS TIMING BETWEEN THE
MAJOR MODELS START TO FALL APART. GFS/GEM SWING A NORTHERN STREAM
SHORTWAVE ACROSS THE GREAT LAKES WHILE DEVELOPING A SURFACE TROUGH
ACROSS THE SOUTHERN PLAINS TO THE OHIO VALLEY. ECMWF HOLDS THE DOME
OF HIGH PRESSURE OVER THE REGION LONGER...ESSENTIALLY DEFLECTING THE
ABOVE MENTIONED SYSTEMS AROUND IT/S PERIPHERY AND AWAY FROM WESTERN
NEW YORK. THIS PHASE DIFFERENCE BETWEEN THE MODELS HOLDS INTO THE
MID WEEK MAKING ANY EXACT PREDICTIONS VERY DICEY. GIVEN THE LEVEL OF
UNCERTAINTY...WILL ELECT TO CONTINUE TRENDING TOWARDS THE GENERIC
HPC BLEND THAT KEEPS CHANCE POPS IN FOR MUCH OF THE WEEK NEXT WEEK
WHICH TEMPERATURES NEAR NORMAL FOR LATE NOVEMBER WITH HIGHS IN THE
40S AND LOWS IN THE LOW TO MID 30S ACROSS MOST LOCALES.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
LIGHT LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO BRING SPOTTY MVFR
CONDITIONS ACROSS THE WESTERN SOUTHERN TIER THROUGH MID MORNING.
EAST OF LAKE ONTARIO A MORE ORGANIZED BAND OF LAKE EFFECT SNOW
WILL BRING LOCAL IFR CONDITIONS IN AREAS BETWEEN KART AND KSYR
THROUGH LATE MORNING BEFORE DISSIPATING BY EARLY AFTERNOON.
OTHERWISE VFR CONDITIONS WILL PREVAIL.
OUTLOOK...
SATURDAY...MAINLY VFR.
SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
MONDAY...MAINLY VFR.
TUESDAY...MAINLY VFR WITH CHANCE OF SHOWERS.
&&
.MARINE...
A STRONG PRESSURE GRADIENT WILL REMAIN IN PLACE BETWEEN HIGH
PRESSURE OVER THE SOUTHEAST STATES AND SEVERAL WAVES OF LOW PRESSURE
OVER THE UPPER GREAT LAKES AND SOUTHEAST CANADA. THIS WILL KEEP HIGH
END SMALL CRAFT ADVISORY CONDITIONS GOING RIGHT THROUGH THE WEEKEND.
MODERATE TO STRONG WESTERLIES WILL CONTINUE TODAY AND GRADUALLY BACK
TO THE SOUTHWEST THEN SSW TONIGHT AND CONTINUE AT 20-30 KNOTS. THE
MODERATE TO STRONG SOUTHWEST WINDS WILL CONTINUE RIGHT THROUGH
SUNDAY BEFORE A COLD FRONT SHIFTS WINDS TO THE NORTHWEST SUNDAY
NIGHT. HIGH PRESSURE WILL BUILD OVER THE REGION MONDAY AND FINALLY
BRING AN END TO THE GUSTY WINDS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...LAKE EFFECT SNOW WARNING UNTIL 11 AM EST THIS MORNING FOR
NYZ006.
LAKE EFFECT SNOW ADVISORY UNTIL 8 AM EST THIS MORNING FOR
NYZ005.
LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NYZ008.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR LEZ020-040-041.
SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR
LOZ042>045.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...TJP
LONG TERM...TJP
AVIATION...HITCHCOCK
MARINE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
100 AM EST FRI NOV 18 2011
.SYNOPSIS...
WESTERLY WINDS WILL BRING LAKE EFFECT SNOWS TO THE SNOW BELT OF
NORTHWESTERN PENNSYLVANIA TONIGHT...BUT HIGH PRESSURE WILL BUILD IN
QUICKLY ON FRIDAY MORNING. THE HIGH WILL SET UP ALONG THE EAST COAST
FOR THIS WEEKEND. A WEAK COLD FRONT WILL LIKELY SAG SOUTHWARD
THROUGH THE AREA LATE SUNDAY. A DEVELOPING STORM SYSTEM IN THE
MISSISSIPPI VALLEY COULD AFFECT CENTRAL PA EITHER TUESDAY OR
WEDNESDAY OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
OOZ HRRR AND 02Z RUC CONFIRMS WHAT WE/RE SEEING ON THE REGIONAL
88D MOSAIC THIS EVENING...WHICH IS A RATHER FRAGMENTED OR CELLUAR
PATTERN TO THE LAKE EFFECT AND ORORGAPHIC SNOW SHOWERS THAT WILL
AFFECT THE NW MTNS OVERNIGHT...AND TO A MUCH LESSER DEGREE - THE
LAUREL HIGHLANDS.
COLDEST MID-LEVEL TEMPS /WITHIN THE 700-500 MB LAYER/ WILL BE
EXITING TO THE NE OF THE REGION OVERNIGHT...THOUGH THE THERMAL
TROUGH AT 850 MB /WITH MIN TEMPS AROUND -10C/ WILL BE CENTERED
ACROSS NRN AND WESTERN PENN THROUGH 12Z FRIDAY.
A FAIRLY WELL-ALIGNED BUT GRADUALLY VEERING WEST TO NW BOUNDARY
LAYER FLOW WILL MAINTAIN NUMEROUS /AND BRIEFLY MDT-HVY/ SNOW
SHOWERS ACROSS THE NW MTNS. ACCUMS NEAR...AND TO THE WEST OF KBFD
WILL NOT ENOUGH TO WARRANT A LES ADVISORY...AND WILL BE MAINLY
BETWEEN 1-2 INCHES OVER A 12-16 HOUR PERIOD. LOCALIZED 3 INCH
AMOUNTS ARE POSSIBLE NEAR AND TO THE WEST OF KBFD...MAINLY TO THE
NORTH OF ROUTE 6.
NARROW BANDS OF LIGHTER SNOW SHOWERS ACROSS THE LAURELS WILL
BRING A LIGHT COATING OF SNOW TO MANY LOCATIONS...WITH UP TO ONE
INCH POSSIBLE ON A FEW OF THE RIDGES WEST OF RT 219.
FOR THE SOUTHEAST TWO THIRDS OF THE REGION...EXPECT A FEW FLURRIES
AND PERHAPS A BRIEF 2-5 MINUTE SNOW SHOWER THROUGH THE OVERNIGHT.
MIN TEMPS TONIGHT /AROUND 20F ACROSS THE NW MTNS AND LAUREL
HIGHLANDS...AND IN THE MID TO UPPER 20S THROUGHOUT THE CENTRAL AND
SE VALLEYS/ WILL BE 5-6F BELOW NORMAL.
THE WIND STAYS GUSTY FOR MUCH OF THE NIGHT DUE TO TIGHT P-GRAD.
GUSTS BETWEEN 25-30 MPH WILL BE COMMON ACROSS THE CENTRAL AND WRN
ZONES. A FEW GUSTS NEAR SNOW SHOWERS COULD RANGE UP TO 35 MPH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
8H TEMPS RISE 10C THROUGH THE DAYLIGHT HRS...AND PUSH ANY
REMAINING LAKE EFFECT SNOW WELL TO THE NORTH IN THE EARLY MORNING.
REST OF THE SHORT TERM SHOULD BE CLEAR. SFC TEMPS MIGHT ONLY
REBOUND ABOUT 15F WITH SHALLOW COLD AIR STUBBORN TO GO AWAY...ESP
IN THE EASTERN VALLEYS. SFC HIGH PASSES TO OUR SOUTH DURING THE
DAY AND SETS UP LIKE A BERMUDA HIGH. CLEAR SKIES AND THE STUBBORN
COOLER AIR IN THE EAST WILL HELP THE ERN COLD SPOTS LIKE SEG AND
THV DIP INTO THE L20S. M-U20S LOOK GOOD FOR MINS ELSEWHERE ESP THE
RIDGES WHERE SRLY WIND WILL KEEP GOING LIGHTLY FOR MUCH OF THE
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
BROAD SOUTHWESTERLY FLOW ALOFT CONTINUES TO BE FORECAST
BY THE LONG TERM MODELS THROUGH AT LEAST THE BEGINNING OF NEXT
WEEK. THIS WILL KEEP TEMPERATURES NEAR TO ABOVE NORMAL THROUGH MUCH
OF THE PERIOD...WITH NO SIGNIFICANT PERIODS OF ARCTIC CHILL IN SITE
AS WE NOW INCLUDE THANKSGIVING DAY IN THIS FORECAST PACKAGE.
SHORTWAVE ENERGY IS FORECAST TO MAKE ITS WAY EAST BY THE MIDDLE OF
NEXT WEEK COMPLICATING THE UPPER FLOW PATTERN.
AS THE UPPER TROUGH BUILDS OVER THE WESTERN U.S. INTO THE
WEEKEND...THE SOUTHEASTERN RIDGE SHOULD PUSH WARMER AIR INTO OUR
REGION BY SATURDAY. THE 850 HPA TEMPERATURES ARE PREDICTED TO BE
1SD ABOVE NORMAL LATE SATURDAY ACROSS THE NW PART OF THE
STATE...AND AREA- WIDE ON SUNDAY. ANOTHER COLD FRONT APPROACHES
WITH THE NEXT CHC FOR SHOWERS LATER SUNDAY INTO MONDAY. THIS FRONT
IS FORECAST TO STALL OVER THE MID ATLANTIC REGION...WITH THE
POTENTIAL FOR A WAVE OF LOW PRESSURE BRINGING MORE PCPN INTO THE
REGION NEXT TUE/WED...BUT THE DETAILS AT THIS POINT ARE ANYTHING
BUT CLEAR.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
INTENSE BANDS OF SNOW SHOWERS OVER N PA AT 06Z. HEAVIEST BANDS
EAST OF BFD...AND ONLY A FEW FLURRIES EXPECTED AT IPT. BANDS
NORTH OF IPT EXTEND INTO SULLIVAN COUNTY...AND CLOUD BANDS
WELL INTO NJ. THUNDER REPORTED EARLIER ON THE SE SHORE OF
LAKE ONT. WILL CONTINUE TO MONITOR.
UPPER LOW MOVES ACROSS STATE TONIGHT WITH HIGH PRESSURE MOVING IN
BEHIND FOR FRI. THIS WILL BRING SNOW SHOWERS OFF OF THE LAKES
THROUGH SUNRISE TO THE NW MTNS...INCLUDING VARIABLE IFR TO VFR
CONDITIONS AT KBFD THROUGH THE OVERNIGHT. ELSEWHERE...THE AIRMASS
IS QUITE DRY...SO EXTENT OF THE SNOW SHOWERS AND LOW CIGS WILL BE
LIMITED TO THE NORTHWEST PART OF THE STATE WITH VFR ELSEWHERE.
WINDS OF 10-15 MPH GUSTING TO 25 MPH WILL GRADUALLY DIMINISH
LATE.
PERIOD OF VFR CONDITIONS FRI MORNING THROUGH SAT NIGHT AS A SW
FLOW OF MILD AIR DEVELOPS ON THE BACK SIDE OF THE HIGH.
OUTLOOK...
FRI-SAT...VFR. NO SIG WX.
SUN...GENERALLY VFR. MVFR IN SHOWERS POSS LATE.
MON-TUE...MVFR TS/SHRA/CIGS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO/LAMBERT
SHORT TERM...DANGELO
LONG TERM...FITZGERALD/GARTNER
AVIATION...MARTIN/RXR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
655 AM EST FRI NOV 18 2011
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS
THE CONUS. SEVERAL WEAK SHORTWAVES WERE EMBEDDED IN THE WRLY FLOW
OVER THE NRN PLAINS AND ADJOINING PORTIONS OF SRN CANADA. A STRONGER
UPPER LEVEL JET AND SHORTWAVE TROUGH THAT WILL IMPACT WEATHER
SATURDAY WAS MOVING INTO THE PAC NW. RADAR RETURNS OVER NRN WI AND
SW UPPER MI WERE INCREASING AS WAA AND ISENTROPIC ASCENT INCREASED
AHEAD OF A SFC TROUGH OVER THE PLAINS. SFC OBS INDICATED THAT THE
PCPN WAS MAINLY ALOFT.
&&
.DISCUSSION...
TODAY AND TONIGHT...THE NAM/GFS SHOW A BAND OF 285-295K ISENTROPIC
LIFT MOVING ACROSS UPPER MI. HOWEVER...THE NAM DEPICTION OF
SLOWER/LESS SATURATION IN THE LOWER LEVELS (BELOW 850 MB) LOOKS MORE
REALISTIC GIVEN UPSTREAM OBS/SOUNDINGS. SO...EXPECT ANY PCPN WILL
BE MORE LIGHT/PATCHY AND ONLY SLIGHT CHANCE TO CHANCE POPS WERE
INCLUDED. AS ANOTHER WEAK SHORTWAVE AND ASSOCIATED AREA OF 700-600 MB
FGEN MOVES INTO WRN LAKE SUPERIOR AND WRN UPPER MI LATE TODAY AND
THIS EVENING...SOME PATCHY LIGHT SNOW OR FLURRIES MAY ALSO PERSIST
INTO THE FAR WEST.
SATURDAY AND SATURDAY NIGHT...A FAST MOVING WAVE IS EXPECTED TO MOVE
FROM THE CENTRAL PLAINS SATURDAY MORNING TO NEAR THE STRAITS BY LATE
SATURDAY EVENING. THE GFS/NAM/ECMWF WERE IN REASONABLE AGREEMENT
WITH THE TRACK OF THE SFC LOW. HOWEVER...SINCE THERE HAS
BEEN SIGNIFICANT VARIATION WITH THE POSITION/STRENGTH OF THE
STRONGEST 800-600 MB FGEN AND THE STRUCTURE/PLACEMENT OF THE COUPLED
UPPER LEVEL JET...CONFIDENCE IN WHERE ANY HEAVY BANDS OF SNOW WILL
SET UP IS LIMITED. MODELS CONSENSUS STILL SUGGESTS THE STRONGER
DYNAMICS WILL AFFECT THE WEST HALF OF UPPER MI. SYNOPTIC QPF AMOUNTS
OF 0.25 TO 0.50 INCH STILL SEEM REASONABLE GIVEN 4 G/KG MOISTURE
AVBL AND THE PERIOD OF STRONG FORCING. SNOW/WATER RATIO VALUES ARE
LIKELY TO REMAIN NEAR OR EVEN BELOW 10/1 WITH THE STRONGER UPWARD
MOTION BELOW THE -12C TO -15C LAYER. ADDITIONAL UPSLOPE AND LAKE
ENHANCEMENT IS EXPECTED NEAR IWD AND OVER N CNTRL UPPER MI.
HOWEVER...THE WINDOW FOR HEAVIER SNOW DURING THE PERIOD OF SYNOPTIC
FORCING IS RELATIVELY SHORT. GIVEN THE AMOUNT OF UNCERTAINTY AND WITH
OVERALL SNOWFALL AMOUNTS EXPECTED TO REMAIN MAINLY IN THE 3 TO 7
INCH RANGE BTWN 18Z SAT AND 12Z SUN AN SPS RATHER THAN A WATCH WAS
ISSUED. A NAM/GFS BLEND OF LOW LEVEL THICKNESS/WET BULB ZERO HEIGHTS
WERE USED FOR PLACEMENT OF THE RAIN SNOW LINE FROM ABOUT KP53 TO JUST
SE OF KIMT.
SUNDAY....N TO NNW WINDS 850 MB TEMP TO AROUND -11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES WILL TAPER OFF.
FOR THE EXTENDED...SFC TROUGH SLIDES ACROSS MAINLY LK SUPERIOR ON
MONDAY LEADING TO WARM AIR ADVECTION ALOFT AND SOME ISENTROPIC LIFT.
GFS/CANADIAN FAVOR A PERIOD OF LGT SNOW MONDAY BUT FOR MOST PART THE
ECMWF REMAINS DRY. GFS FCST SOUNDINGS SHOW DEEP MOISTURE AND LIFT
ACTING UPON FAVORABLE TEMPS FOR SNOW INITIATION...SO AT LEAST THE
GFS QPF IS CONSISTENT WITH ITS OTHER MODEL FIELDS. SHORTWAVE IS FCST
TO TRACK MAINLY ACROSS LK SUPERIOR AND WOULD EXPECT GREATEST CHANCE
OF SATURATION/PCPN TO OCCUR THERE AS WELL. ONLY HAVE CHANCE POPS ON
THE KEWEENAW. EVEN IF GFS IS CORRECT...WOULD ONLY SEE SUB ADVY SNOW
AMOUNTS...AND THAT IS PRETTY GENEROUS. AFTER TROUGH EXITS...LOOKS
LIKE A QUIET PERIOD OF WEATHER OVR UPR LAKES LEADING INTO THE
THANKSGIVING HOLIDAY AS WRLY FLOW KEEPS MAIN STORM TRACK SUPPRESSED
TO SOUTH. MAY BE A SYSTEM THAT AFFECTS LOWER MICHIGAN LATER TUESDAY
INTO TUESDAY NIGHT...BUT THAT SHOULD BE GONE BY THE BUSY WEDNESDAY
TRAVEL DAY WITH HIGH PRESSURE BUILDING OVR UPR LAKES REGION.
SEEMS LIKE NICE WARMUP COULD OCCUR ON THANKSGIVING ONCE THE HIGH
MOVES EAST LEADING TO RETURN SW FLOW AT SFC. GFS SOUNDINGS SHOW
LOWER INVERSION BUT EVEN LIMITED MIXING YIELDS HIGHS WELL INTO THE
40S. GIVEN THE SW WINDS...INCREASED TEMPS FOR DOWNSLOPE AREAS NEAR
LK SUPERIOR TOWARD 50 DEGREES...CLOSER TO BIAS CORRECTED CONSENSUS.
LOOKS LIKE VERY NICE WEATHER FOR THE THANKSGIVING HOLIDAY...AND
LIKELY INTO FRIDAY TOO AS SW WINDS CONTINUE TO PUSH WARM AIR INTO
THE UPR LAKES AHEAD OF DEVELOPING TROUGH OVR THE PLAINS. RECORD
HIGHS FOR 24-25 NOVEMBER ARE MAINLY IN THE MID TO UPR 50S ACROSS THE
CWA.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
EXTENSIVE BKN MID CLOUDS SPREAD OVER UPR MICHIGAN INTO THIS EVENING.
WARM FRONT ALOFT MAY TRIGGER FLURRIES AT KCMX THIS MORNING. EVEN
SO...VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING AT ALL SITES.
BY LATE TONIGHT...PASSAGE OF WEAK LOW PRESSURE TROUGH MAY RESULT IN
CIGS BECOMING MVFR AT KIWD AND KCMX.
HEADS UP THAT AFTER FAIRLY BENIGN CONDITIONS THROUGH TONIGHT AND
SATURDAY MORNING...WIDESPREAD IFR/LIFR CONDITIONS ARE EXPECTED
BEGINNING SATURDAY AFTN AT ALL THREE TAF SITES AS LOW PRESSURE
SYSTEM WITH WIDESPREAD/STEADY WET SNOW WORKS ACROSS MOST OF UPPER
MICHIGAN. CONDITIONS WILL NOT IMPROVE UNTIL SUNDAY MORNING AS THE
LOW MOVES AWAY FROM THE AREA. &&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
WEST-TO-EAST ORIENTED SFC TROUGH PASSES ACROSS LK SUPERIOR TODAY
LEADING TO DEVELOPING SE WINDS OVR WESTERN LK AND GUSTY SOUTHERLY
WINDS TO 30 KTS OVER EASTERN SECTIONS. WINDS DIMINISH TONIGHT...THEN
INCREASE BY LATE SATURDAY WITH ARRIVAL OF LOW PRESSURE SYSTEM FM THE
SOUTHERN PLAINS. SFC LOW NOT FCST TO DEEPEN SIGNIFICANTLY BUT THERE
IS DECENT COLD AIR RUSHING IN FM THE NORTH IN WAKE OF THE SYSTEM.
CANNOT RULE OUT LOW END NORTHERLY GALES SATURDAY NIGHT OVER CNTRL LK
SUPERIOR. NOT NEAR ENOUGH CONFIDENCE TO ISSUE GALE WATCH AT THIS
POINT THOUGH. SHOULD BE A WIDESPREAD SNOW OVER MOST OF LK SUPERIOR
AS THE LOW MOVES THROUGH THE AREA. LOW THEN QUICKLY SLIDES EAST
SUNDAY AND WINDS DIMINISH BY SUNDAY AFTN. WINDS SHOULD STAY LESS
THAN 25 KTS EARLY NEXT WEEK AS A WEAK TROUGH MOVES ACROSS FOLLOWED
BY A LARGE AREA OF HIGH PRESSURE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
EXTENDED...JLA
AVIATION...JLA
MARINE...JLA
CORRECTED EXTENDED FORECAST DISCUSSION
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS
THE CONUS. SEVERAL WEAK SHORTWAVES WERE EMBEDDED IN THE WRLY FLOW
OVER THE NRN PLAINS AND ADJOINING PORTIONS OF SRN CANADA. A STRONGER
UPPER LEVEL JET AND SHORTWAVE TROUGH THAT WILL IMPACT WEATHER
SATURDAY WAS MOVING INTO THE PAC NW. RADAR RETURNS OVER NRN WI AND
SW UPPER MI WERE INCREASING AS WAA AND ISENTROPIC ASCENT INCREASED
AHEAD OF A SFC TROUGH OVER THE PLAINS. SFC OBS INDICATED THAT THE
PCPN WAS MAINLY ALOFT.
&&
.DISCUSSION...
TODAY AND TONIGHT...THE NAM/GFS SHOW A BAND OF 285-295K ISENTROPIC
LIFT MOVING ACROSS UPPER MI. HOWEVER...THE NAM DEPICTION OF
SLOWER/LESS SATURATION IN THE LOWER LEVELS (BELOW 850 MB) LOOKS MORE
REALISTIC GIVEN UPSTREAM OBS/SOUNDINGS. SO...EXPECT ANY PCPN WILL
BE MORE LIGHT/PATCHY AND ONLY SLIGHT CHANCE TO CHANCE POPS WERE
INCLUDED. AS ANOTHER WEAK SHORTWAVE AND ASSOCIATED AREA OF 700-600 MB
FGEN MOVES INTO WRN LAKE SUPERIOR AND WRN UPPER MI LATE TODAY AND
THIS EVENING...SOME PATCHY LIGHT SNOW OR FLURRIES MAY ALSO PERSIST
INTO THE FAR WEST.
SATURDAY AND SATURDAY NIGHT...A FAST MOVING WAVE IS EXPECTED TO MOVE
FROM THE CENTRAL PLAINS SATURDAY MORNING TO NEAR THE STRAITS BY LATE
SATURDAY EVENING. THE GFS/NAM/ECMWF WERE IN REASONABLE AGREEMENT
WITH THE TRACK OF THE SFC LOW. HOWEVER...SINCE THERE HAS
BEEN SIGNIFICANT VARIATION WITH THE POSITION/STRENGTH OF THE
STRONGEST 800-600 MB FGEN AND THE STRUCTURE/PLACEMENT OF THE COUPLED
UPPER LEVEL JET...CONFIDENCE IN WHERE ANY HEAVY BANDS OF SNOW WILL
SET UP IS LIMITED. MODELS CONSENSUS STILL SUGGESTS THE STRONGER
DYNAMICS WILL AFFECT THE WEST HALF OF UPPER MI. SYNOPTIC QPF AMOUNTS
OF 0.25 TO 0.50 INCH STILL SEEM REASONABLE GIVEN 4 G/KG MOISTURE
AVBL AND THE PERIOD OF STRONG FORCING. SNOW/WATER RATIO VALUES ARE
LIKELY TO REMAIN NEAR OR EVEN BELOW 10/1 WITH THE STRONGER UPWARD
MOTION BELOW THE -12C TO -15C LAYER. ADDITIONAL UPSLOPE AND LAKE
ENHANCEMENT IS EXPECTED NEAR IWD AND OVER N CNTRL UPPER MI.
HOWEVER...THE WINDOW FOR HEAVIER SNOW DURING THE PERIOD OF SYNOPTIC
FORCING IS RELATIVELY SHORT. GIVEN THE AMOUNT OF UNCERTAINTY AND WITH
OVERALL SNOWFALL AMOUNTS EXPECTED TO REMAIN MAINLY IN THE 3 TO 7
INCH RANGE BTWN 18Z SAT AND 12Z SUN AN SPS RATHER THAN A WATCH WAS
ISSUED. A NAM/GFS BLEND OF LOW LEVEL THICKNESS/WET BULB ZERO HEIGHTS
WERE USED FOR PLACEMENT OF THE RAIN SNOW LINE FROM ABOUT KP53 TO JUST
SE OF KIMT.
SUNDAY....N TO NNW WINDS 850 MB TEMP TO AROUND -11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES WILL TAPER OFF.
FOR THE EXTENDED...SFC TROUGH SLIDES ACROSS MAINLY LK SUPERIOR ON
MONDAY LEADING TO WARM AIR ADVECTION ALOFT AND SOME ISENTROPIC LIFT.
GFS/CANADIAN FAVOR A PERIOD OF LGT SNOW MONDAY BUT FOR MOST PART THE
ECMWF REMAINS DRY. GFS FCST SOUNDINGS SHOW DEEP MOISTURE AND LIFT
ACTING UPON FAVORABLE TEMPS FOR SNOW INITIATION...SO AT LEAST THE
GFS QPF IS CONSISTENT WITH ITS OTHER MODEL FIELDS. SHORTWAVE IS FCST
TO TRACK MAINLY ACROSS LK SUPERIOR AND WOULD EXPECT GREATEST CHANCE
OF SATURATION/PCPN TO OCCUR THERE AS WELL. ONLY HAVE CHANCE POPS ON
THE KEWEENAW. EVEN IF GFS IS CORRECT...WOULD ONLY SEE SUB ADVY SNOW
AMOUNTS...AND THAT IS PRETTY GENEROUS. AFTER TROUGH EXITS...LOOKS
LIKE A QUIET PERIOD OF WEATHER OVR UPR LAKES LEADING INTO THE
THANKSGIVING HOLIDAY AS WRLY FLOW KEEPS MAIN STORM TRACK SUPPRESSED
TO SOUTH. MAY BE A SYSTEM THAT AFFECTS LOWER MICHIGAN LATER TUESDAY
INTO TUESDAY NIGHT...BUT THAT SHOULD BE GONE BY THE BUSY WEDNESDAY
TRAVEL DAY WITH HIGH PRESSURE BUILDING OVR UPR LAKES REGION.
SEEMS LIKE NICE WARMUP COULD OCCUR ON THANKSGIVING ONCE THE HIGH
MOVES EAST LEADING TO RETURN SW FLOW AT SFC. GFS SOUNDINGS SHOW
LOWER INVERSION BUT EVEN LIMITED MIXING YIELDS HIGHS WELL INTO THE
40S. GIVEN THE SW WINDS...INCREASED TEMPS FOR DOWNSLOPE AREAS NEAR
LK SUPERIOR TOWARD 50 DEGREES...CLOSER TO BIAS CORRECTED CONSENSUS.
LOOKS LIKE VERY NICE WEATHER FOR THE THANKSGIVING HOLIDAY...AND
LIKELY INTO FRIDAY TOO AS SW WINDS CONTINUE TO PUSH WARM AIR INTO
THE UPR LAKES AHEAD OF DEVELOPING TROUGH OVR THE PLAINS. RECORD
HIGHS FOR 24-25 NOVEMBER ARE MAINLY IN THE MID TO UPR 50S ACROSS THE
CWA.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
AS WINDS BECOME MORE SOUTHERLY WITH TIME...THE LAKE EFFECT SNOW
SHOWERS AND BANDS WILL PUSH OFFSHORE FROM KCMX OVERNIGHT AND MVFR
CIGS OR VIS IN THE SNOWBANDS WILL IMPROVE TO VFR AND THIS SHOULD
LAST THROUGH THE REST OF THE PERIOD.
VFR CONDITIONS AT BOTH KIWD AND KSAW THROUGH THE PERIOD. AS WINDS
DECOUPLE LATE TONIGHT...PUT IN SOME LLWS AT KIWD THAT WILL LAST INTO
FRIDAY MID MORNING. WINDS WILL GET GUSTY AT KSAW FRIDAY.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
WEST-TO-EAST ORIENTED SFC TROUGH PASSES ACROSS LK SUPERIOR TODAY
LEADING TO DEVELOPING SE WINDS OVR WESTERN LK AND GUSTY SOUTHERLY
WINDS TO 30 KTS OVER EASTERN SECTIONS. WINDS DIMINISH TONIGHT...THEN
INCREASE BY LATE SATURDAY WITH ARRIVAL OF LOW PRESSURE SYSTEM FM THE
SOUTHERN PLAINS. SFC LOW NOT FCST TO DEEPEN SIGNIFICANTLY BUT THERE
IS DECENT COLD AIR RUSHING IN FM THE NORTH IN WAKE OF THE SYSTEM.
CANNOT RULE OUT LOW END NORTHERLY GALES SATURDAY NIGHT OVER CNTRL LK
SUPERIOR. NOT NEAR ENOUGH CONFIDENCE TO ISSUE GALE WATCH AT THIS
POINT THOUGH. SHOULD BE A WIDESPREAD SNOW OVER MOST OF LK SUPERIOR
AS THE LOW MOVES THROUGH THE AREA. LOW THEN QUICKLY SLIDES EAST
SUNDAY AND WINDS DIMINISH BY SUNDAY AFTN. WINDS SHOULD STAY LESS
THAN 25 KTS EARLY NEXT WEEK AS A WEAK TROUGH MOVES ACROSS FOLLOWED
BY A LARGE AREA OF HIGH PRESSURE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
EXTENDED...JLA
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
559 AM EST FRI NOV 18 2011
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS
THE CONUS. SEVERAL WEAK SHORTWAVES WERE EMBEDDED IN THE WRLY FLOW
OVER THE NRN PLAINS AND ADJOINING PORTIONS OF SRN CANADA. A STRONGER
UPPER LEVEL JET AND SHORTWAVE TROUGH THAT WILL IMPACT WEATHER
SATURDAY WAS MOVING INTO THE PAC NW. RADAR RETURNS OVER NRN WI AND
SW UPPER MI WERE INCREASING AS WAA AND ISENTROPIC ASCENT INCREASED
AHEAD OF A SFC TROUGH OVER THE PLAINS. SFC OBS INDICATED THAT THE
PCPN WAS MAINLY ALOFT.
&&
.DISCUSSION...
TODAY AND TONIGHT...THE NAM/GFS SHOW A BAND OF 285-295K ISENTROPIC
LIFT MOVING ACROSS UPPER MI. HOWEVER...THE NAM DEPICTION OF
SLOWER/LESS SATURATION IN THE LOWER LEVELS (BELOW 850 MB) LOOKS MORE
REALISTIC GIVEN UPSTREAM OBS/SOUNDINGS. SO...EXPECT ANY PCPN WILL
BE MORE LIGHT/PATCHY AND ONLY SLIGHT CHANCE TO CHANCE POPS WERE
INCLUDED. AS ANOTHER WEAK SHORTWAVE AND ASSOCIATED AREA OF 700-600 MB
FGEN MOVES INTO WRN LAKE SUPERIOR AND WRN UPPER MI LATE TODAY AND
THIS EVENING...SOME PATCHY LIGHT SNOW OR FLURRIES MAY ALSO PERSIST
INTO THE FAR WEST.
SATURDAY AND SATURDAY NIGHT...A FAST MOVING WAVE IS EXPECTED TO MOVE
FROM THE CENTRAL PLAINS SATURDAY MORNING TO NEAR THE STRAITS BY LATE
SATURDAY EVENING. THE GFS/NAM/ECMWF WERE IN REASONABLE AGREEMENT
WITH THE TRACK OF THE SFC LOW. HOWEVER...SINCE THERE HAS
BEEN SIGNIFICANT VARIATION WITH THE POSITION/STRENGTH OF THE
STRONGEST 800-600 MB FGEN AND THE STRUCTURE/PLACEMENT OF THE COUPLED
UPPER LEVEL JET...CONFIDENCE IN WHERE ANY HEAVY BANDS OF SNOW WILL
SET UP IS LIMITED. MODELS CONSENSUS STILL SUGGESTS THE STRONGER
DYNAMICS WILL AFFECT THE WEST HALF OF UPPER MI. SYNOPTIC QPF AMOUNTS
OF 0.25 TO 0.50 INCH STILL SEEM REASONABLE GIVEN 4 G/KG MOISTURE
AVBL AND THE PERIOD OF STRONG FORCING. SNOW/WATER RATIO VALUES ARE
LIKELY TO REMAIN NEAR OR EVEN BELOW 10/1 WITH THE STRONGER UPWARD
MOTION BELOW THE -12C TO -15C LAYER. ADDITIONAL UPSLOPE AND LAKE
ENHANCEMENT IS EXPECTED NEAR IWD AND OVER N CNTRL UPPER MI.
HOWEVER...THE WINDOW FOR HEAVIER SNOW DURING THE PERIOD OF SYNOPTIC
FORCING IS RELATIVELY SHORT. GIVEN THE AMOUNT OF UNCERTAINTY AND WITH
OVERALL SNOWFALL AMOUNTS EXPECTED TO REMAIN MAINLY IN THE 3 TO 7
INCH RANGE BTWN 18Z SAT AND 12Z SUN AN SPS RATHER THAN A WATCH WAS
ISSUED. A NAM/GFS BLEND OF LOW LEVEL THICKNESS/WET BULB ZERO HEIGHTS
WERE USED FOR PLACEMENT OF THE RAIN SNOW LINE FROM ABOUT KP53 TO JUST
SE OF KIMT.
SUNDAY....N TO NNW WINDS 850 MB TEMP TO AROUND -11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES WILL TAPER OFF.
FOR THE EXTENDED...PRETTY GOOD AGREEMENT FM GFS/ECMWF/CANADIAN THAT
UPR LEVELS SHOW INCREASING TROFFINESS BY LATE WEEKEND. MODELS HAVE
LATCHED ONTO A STRONGER SHORTWAVE DROPPING THROUGH SUNDAY INTO
SUNDAY NIGHT ALONG WITH A SFC LOW SLIDING ACROSS UPR LAKES. SLIGHT
DIFFERENCES WITH TRACK OF SFC LOW...BUT ALL GUIDANCE INDICATES WARM
AIR ADVECTION AHEAD OF TROUGH AND DIVERGENCE ALOFT FM JET DIGGING IN
ON BACK SIDE OF TROUGH INTO UPR MISSISSIPPI RIVER VALLEY WILL SUPPORT
SOME SHRA WORKING THROUGH UPR MI SUNDAY AND SUNDAY NIGHT. MODEL
CONSENSUS POINTED TO CHANCE POPS OVR WEST HALF OF CWA ON SUNDAY THEN
MOVING INTO EASTERN CWA SUNDAY NIGHT. ABOVE AVERAGE CONFIDENCE IN
TIMING/EXTENT OF RAIN CHANCES THROUGH SUNDAY. RIDGE WORKS ACROSS FOR
MONDAY WITH MAINLY DRY WX FIGURED.
BEYOND MONDAY...ANOTHER TROUGH IS FCST TO COME ACROSS UPR LAKES IN
FLATTENING UPR FLOW. THE FLOW BECOMING MORE ZONAL IS LEADING TO
TIMING DIFFERENCES IN THE MODELS. GFS IS QUICKEST WITH NEXT SFC
TROUGH...PUSHING IT COMPLETELY THROUGH AREA BY WEDNESDAY MORNING.
LATEST ECMWF/CANADIAN ARE MUCH SLOWER AND MORE AMPLIFIED...WITH A
STRONG SFC LOW FCST TO MEANDER OVR UPR LAKES THROUGH AT LEAST
WEDNESDAY. GFS HAS BETTER RUN-TO-RUN CONSISTENCY AND MATCHED
CONTINUITY SO DID SIDE WITH THAT IDEA FOR NOW. TOUGH TO BET AGAINST
ECMWF IN THE EXTENDED PERIODS THOUGH...SO HAVE LOWER CONFIDENCE IN
EXTENDED BEYOND MONDAY DUE TO THE TIMING DIFFERENCES IN MODELS. WHAT
IS AGREED UPON BY MODELS IS COOL DOWN BEHIND THIS SYSTEM MID-LATE
WEEK WITH POSSIBLE RAIN/SNOW SHOWERS. THE MAIN QUESTION IS JUST HOW
QUICK THIS WILL OCCUR.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
AS WINDS BECOME MORE SOUTHERLY WITH TIME...THE LAKE EFFECT SNOW
SHOWERS AND BANDS WILL PUSH OFFSHORE FROM KCMX OVERNIGHT AND MVFR
CIGS OR VIS IN THE SNOWBANDS WILL IMPROVE TO VFR AND THIS SHOULD
LAST THROUGH THE REST OF THE PERIOD.
VFR CONDITIONS AT BOTH KIWD AND KSAW THROUGH THE PERIOD. AS WINDS
DECOUPLE LATE TONIGHT...PUT IN SOME LLWS AT KIWD THAT WILL LAST INTO
FRIDAY MID MORNING. WINDS WILL GET GUSTY AT KSAW FRIDAY.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
WEST-TO-EAST ORIENTED SFC TROUGH PASSES ACROSS LK SUPERIOR TODAY
LEADING TO DEVELOPING SE WINDS OVR WESTERN LK AND GUSTY SOUTHERLY
WINDS TO 30 KTS OVER EASTERN SECTIONS. WINDS DIMINISH TONIGHT...THEN
INCREASE BY LATE SATURDAY WITH ARRIVAL OF LOW PRESSURE SYSTEM FM THE
SOUTHERN PLAINS. SFC LOW NOT FCST TO DEEPEN SIGNIFICANTLY BUT THERE
IS DECENT COLD AIR RUSHING IN FM THE NORTH IN WAKE OF THE SYSTEM.
CANNOT RULE OUT LOW END NORTHERLY GALES SATURDAY NIGHT OVER CNTRL LK
SUPERIOR. NOT NEAR ENOUGH CONFIDENCE TO ISSUE GALE WATCH AT THIS
POINT THOUGH. SHOULD BE A WIDESPREAD SNOW OVER MOST OF LK SUPERIOR
AS THE LOW MOVES THROUGH THE AREA. LOW THEN QUICKLY SLIDES EAST
SUNDAY AND WINDS DIMINISH BY SUNDAY AFTN. WINDS SHOULD STAY LESS
THAN 25 KTS EARLY NEXT WEEK AS A WEAK TROUGH MOVES ACROSS FOLLOWED
BY A LARGE AREA OF HIGH PRESSURE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
EXTENDED...JLA
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DENVER CO
1010 AM MST FRI NOV 18 2011
.UPDATE...ONGOING FORECASTS STILL ON TRACK. CURRENTLY...WINDS ACROSS
MOUNTAINS AND ALONG FOOTHILLS BEGINNING TO DECREASE...IN LINE WITH
LATEST MODEL CROSS SECTIONS. WINDS TO INCREASE AGAIN AFTER
MIDNIGHT AS MODEL CROSS SECTIONS SHOW CROSS MOUNTAIN FLOW
INCREASING TO AROUND 75 KTS ALONG THE FOOTHILLS AFTER 09Z...IN
LINE WITH THE GREATEST DOWNWARD MOTION. SO CONCERN STILL EXISTS
FOR HIGH WIND POTENTIAL ALONG FOOTHILLS...SOUTH PARK AND PORTIONS
OF THE PALMER DIVIDE. THERE IS STILL A BIT OF VERTICAL SHEAR
ASSOCIATED WITH THE INCOMING JET WHICH COULD LIMIT THE HIGH WIND
POTENTIAL...SO WILL MAINTAIN THE HIGH WIND WATCH FOR NOW AND TAKE
A CLOSER LOOK FOR THE AFTERNOON PACKAGE. AS FOR SNOW POTENTIAL
TONIGHT...CROSS SECTIONS INDICATE AN INCREASE IN MOISTURE OVER
THE MOUNTAINS CLOSER TO MIDNIGHT...WHICH COULD DELAY THE TIMING OF
THE SNOW FOR ZONE 31. WILL LEAVE THE SLIGHT CHANCE THERE AFTER 00Z
FOR NOW.
&&
.AVIATION...CURRENT TAF TRENDS STILL LOOKING ON TRACK...WITH WIND
BEING THE MAIN ISSUE THROUGH TONIGHT. LATEST HRRR AND RUC STILL
BRING A WESTERLY PUSH OF WIND ACROSS THE AREA AIRPORTS BETWEEN 17Z
AND 21Z. WILL MAINTAIN THIS TREND IN THE 18Z TAFS. NO MAJOR
CHANGES NEEDED. LATEST NAM SUGGESTING FROPA AND NORTHERLY SURGE
AROUND 18Z AT DIA...THEN EASTERLY BY 21Z. THIS SEEMS REASONABLE...AND
WILL FOLLOW THIS TREND. NAM ALSO SUGGESTS A CEILING OF AROUND 6000
FEET AGL AFTER 21Z AND WILL ADD THIS IN A TEMPO GROUP. NO WEATHER
ANTICIPATED AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 340 AM MST FRI NOV 18 2011/
SHORT TERM...MAIN CONCERN AGAIN FOR THE NEXT 24 HOURS IS THE STRONG
WIND POTENTIAL OVER THE MOUNTAINS AND FOOTHILLS AND SNOW SPREADING
INTO THE MOUNTAINS LATER TONIGHT. CURRENTLY A STRONG WESTERLY FLOW
ALOFT WITH SOME GUSTY WINDS IN THE MOUNTAINS AND FOOTHILLS. MOST OF
THE WINDS IN THE 15 TO 25 MPH WITH SOME HIGHER GUSTS IN THE 30-45
MPH RANGE. FOR MOST OF TODAY AND THIS EVENING...WINDS SHOULD REMAIN
BELOW HIGH WIND CRITERIA.
DEEP LOW PRESSURE WILL REMAIN OFF THE PACIFIC NORTHWEST COAST AND
SPIN OUT A WAVE WHICH WILL MOVE INTO COLORADO LATER TONIGHT. CROSS
SECTIONS SHOW CROSS BARRIER FLOW INCREASING LATER TONIGHT WITH
60-80KT COMING DOWN THE SLOPE AFTER 09Z. THIS SEEMS TO CORRESPOND
WITH STRONGER DOWNWARD VERTICAL VELOCITIES DEVELOPING BELOW 600MB
EARLY SAT AM. THIS MAY HELP IN AIDING THE STRONGEST WINDS TO THE
SURFACE. THERE IS A FAIRLY DECENT STABILITY THAT ALSO DEVELOPS AT
700MB. ON THE NEGATIVE SIDE FOR HIGH WINDS...THERE IS A FAIR AMOUNT
OF VERTICAL SHEAR WITH THE INCOMING JET AND MOISTURE/PRECIP
DEVELOPING IN THE MOUNTAINS MAY REDUCE THE AMPLIFICATION OF THE
WAVE. APPEARS LIKE THE WINDOW FOR THE STRONGEST WINDS WOULD BE
BETWEEN 09Z-15Z ON SATURDAY...AND FAVOR SOUTHERN SECTIONS INCLUDING
JEFFERSON...PARK AND WESTERN DOUGLAS COUNTIES AS THE FLOW IS A BIT
MORE SOUTHWEST. FOR NOW WITH STILL QUITE A BIT OF UNCERTAINTY...
WILL ONLY GO WITH A HIGH WIND WATCH GIVEN THE POTENTIAL FOR HIGH
WINDS AND WILL COVER ZONES 35>37 AND 41.
MOISTURE WILL SPREAD INTO THE MOUNTAINS LATER TONIGHT WITH SNOW
DEVELOPING...MAINLY OVER ZONE 31 AND 33. GIVEN THE STRONG SOUTHWEST
FLOW...ZONE 34 INCLUDING SUMMIT COUNTY WILL ONLY SEE SCATTERED SNOW
SHOWERS WITH UNPREFERRED OROGRAPHIC DIRECTION.
LONG TERM...JET MAX AND TROUGH AXIS WILL BE RIGHT OVER COLORADO
EARLY SATURDAY MORNING. CONCERN WILL CONTINUE TO BE HIGH WINDS
THROUGH THE MORNING FOR THE FOOTHILLS AND EASTERN SLOPES OF THE
NORTHERN AND CENTRAL MOUNTAINS AS WELL AS FOR SOUTH PARK AND SOME
AREAS OF THE PALMER DIVIDE. BY NOON...THE JET WILL LIFT NORTH...THE
SURFACE PRESSURE GRADIENT WILL RELAX AND THE COLD FRONT WILL MOVE
SOUTH ACROSS THE FORECAST AREA. THEREFORE WILL HAVE THE WATCH PERIOD
ONLY ENCOMPASS THE MORNING HOURS. WINDS BEHIND THE FRONT WILL BE
STRONG OUT OF THE NORTH AS WELL...HOWEVER NOT STRONG ENOUGH FOR ANY
HIGHLIGHT.
SNOW WILL CONTINUE OVER THE HIGH COUNTRY SATURDAY MORNING WITH
ANOTHER FEW INCHES EXPECTED. THE PARK AND NORTHERN GORE RANGES WILL
SEE THE HEAVIEST AMOUNTS WITH LESS EXPECTED SOUTH TOWARD THE I70
CORRIDOR. THE STRONG WINDS SATURDAY MORNING WILL CREATE AREAS OF
BLOWING SNOW ESPECIALLY OVER PASSES. THE STRONG MOUNTAIN LEVEL WINDS
ALONG WITH A LEESIDE SURFACE LOW OVER THE WESTERN PLAINS THROUGH THE
EVENING WILL KEEP THE PLAINS DRY AS WELL AS LESS SNOW AMOUNTS FOR
THE EASTERN SLOPES OF THE HIGHER MOUNTAINS AS WELL AS THE FOOTHILLS.
THIS LEESIDE LOW WILL ALSO KEEP TEMPERATURES WARMER THAN PREVIOUS
FORECASTS ESPECIALLY OVER THE WESTERN PLAINS. HAVE INCREASED THE
HIGHS INTO THE 50S FOR THE PLAINS. AS HIGH SURFACE PRESSURE FROM THE
NORTHERN GREAT PLAINS PUSHES DOWN INTO NORTHEASTERN COLORADO...THE
MOISTURE WILL NOT BE AVAILABLE ANYMORE FOR THE SHORT PERIOD OF
UPSLOPE FLOW TO PRODUCE ANYTHING.
SOUTHWEST FLOW WILL CONTINUE THROUGH MONDAY AS ANOTHER WEATHER
DISTURBANCE OUT OF THE DESERT SOUTHWEST TRANSITIONS OVER THE STATE
EARLY TUESDAY MORNING. ENOUGH MOISTURE IN THE FLOW WILL KEEP A
CHANCE OF SNOW OVER THE MOUNTAINS THROUGH THIS PERIOD. TEMPERATURES
SUNDAY AND MONDAY RIGHT AROUND NORMAL FOR THIS TIME WITH
TEMPERATURES IN THE UPPER 40S FOR THE PLAINS AND IN THE 30S FOR THE
MOUNTAINS. AS THE SECOND SYSTEM PASSES...MODELS ARE IN GOOD
AGREEMENT FOR TUESDAY THROUGH THANKSGIVING TO SEE WARMER THAN
AVERAGE TEMPERATURES AND DRY CONDITIONS AS AN UPPER RIDGE BUILDS IN.
MODELS ALSO AGREEING ON ANOTHER UPPER TROUGH TO PASS OVER THE STATE
THE NEXT DAY ON FRIDAY. THIS WILL LIKELY PRODUCE MORE SEASONAL
WEATHER INCLUDING MOUNTAIN SNOWS FOR THANKSGIVING WEEKEND.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT WITH JUST
VARYING AMOUNTS OF SCT-BKN HIGH LEVEL CLOUDS. TYPICAL DRAINAGE WINDS
FROM THE SOUTH EARLY THIS AM THEN A BIT OF A CHALLENGE THIS
AFTERNOON. DESPITE THE CURRENT SOUTHEAST AFTERNOON WINDS IN THE TAF
THINK THINGS MAY DEVELOP MORE LIKE YESTERDAY WITH SOME WESTERLY
WINDS SPILLING OUT BY MID-LATE AFTERNOON...ESP AT BJC AND DEN. WILL
ADJUST 12Z TAFS TO SHOW MORE OF THE SOUTHWEST TO WEST WINDS. THE
WEST TO SOUTHWEST WINDS WILL INCREASE AGAIN LATER TNT...ESP AT BJC
WITH GUSTS 30 TO 40KTS POSSIBLE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR
COZ035>037-041.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
121 PM EST FRI NOV 18 2011
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER OVER THE AREA THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. LOW LEVEL EASTERLY FLOW MAY INCREASE
LOW CLOUDS OVER THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
DRY HIGH PRESSURE CENTERED OVER NORTH CAROLINA WILL DOMINATE
TODAY. THE LATEST SATELLITE TRENDS AND THE MODELS INDICATED
CONTINUED CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
DRY RIDGING SHOULD CONTINUE TO DOMINATE TONIGHT. PRECIPITABLE
WATER VALUES WILL BE EXTREMELY LOW...LESS THAN A QUARTER INCH. EXPECT
LOWS IN THE UPPER 20S TO LOWER 30S UNDER STRONG RADIATIONAL
COOLING CONDITIONS. ONE POTENTIAL FLY IN THE OINTMENT OVERNIGHT
WILL BE THE POSSIBILITY OF STRATOCUMULUS MOVING IN OFF THE COAST
AS THE LOW LEVEL FLOW SHIFTS MORE SOUTHERLY ALLOWING ATLANTIC
MOISTURE TO OVERSPREAD THE REGION.
BY SATURDAY THE AIR MASS BEGINS TO MODIFY AND SURFACE HIGH PRESSURE
SHIFTS OFF THE COAST ALLOWING FOR A RETURN SOUTHERLY FLOW. UPPER
HEIGHTS WILL ALSO BE RISING IN RESPONSE TO TROUGHING UPSTREAM OVER
THE WESTERN PART OF THE COUNTRY. MAX TEMPERATURES SHOULD RISE BACK
INTO THE 60S SATURDAY AFTERNOON DESPITE SOME POSSIBLE CLOUD COVER.
LOW LEVEL FLOW OFF THE ATLANTIC WILL CONTINUE TO INCREASE
ATMOSPHERIC MOISTURE AS PRECIPITABLE WATER VALUES RETURN TO NEAR 1
INCH BY SUNDAY MORNING. PRE-DAWN STRATUS EARLY SUNDAY WILL LIMIT
THE AMOUNT OF COOLING AND THEREFORE EXPECT WARMER MIN TEMPERATURES
SATURDAY NIGHT. CONTINUED WARMING ON SUNDAY AS HIGHS PUSH INTO THE
LOWER 70S WITH WARM ADVECTION.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED MONDAY AND TUESDAY AS
UPPER HEIGHTS RISE AND SOUTHERLY FLOW AROUND THE SURFACE HIGH
BRINGS WARMER AIR NORTHWARD. TIMING FOR ANOTHER COLD FRONT
CROSSING THE AREA LOOKS TO BE TUESDAY NIGHT INTO WEDNESDAY
MORNING BRINGING THE NEXT CHANCE OF PRECIPITATION. FOR NOW POPS
WILL BE IN THE LOW CHANCE RANGE WITH THE FRONTAL PASSAGE. COLD
HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE FRONT THURSDAY
PROVIDING DRY WEATHER AND BELOW NORMAL TEMPERATURES.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL MOVE EAST THIS EVENING. THIS WILL ALLOW 2 KFT
WINDS TO THE SOUTHEAST AND ADVECT MOISTURE INTO THE REGION LATE
TONIGHT AFTER MIDNIGHT. WILL KEEP MAINLY VFR CONDITIONS OVERNIGHT
AS AIRMASS REMAINS TO BE DRY. BOTH NAM AND RUC SHOW SOUTHEAST WINDS
BRINGING MOISTURE IN THE FORM OF CLOUDS AFTER MIDNIGHT. WILL KEEP
CLOUDS SCATTERED NEAR 2 KFT 06Z SOUTH LIKE AGS AND OGB AND 08Z TAF
SITES NORTH OF THERE. WITH DRY AIR...THINK CEILINGS WILL BE SLOW
TO DEVELOP. SO...DECIDED TO GO JUST SCATTERED UNTIL 12Z-14Z TIME
FRAME. WILL HAVE MVFR CEILINGS SOUTH TAF SITES OF OGB AND AGS
THEN MOVING NORTH TO REMAINING TAF SITES BY 14Z. THERE SHOULD BE
SOME WEAK ISENTROPIC LIFT AS WELL BUT MOIST LAYERS APPEARS TO BE
TOO SHALLOW TO GIVE ANY PRECIPITATION SATURDAY. AIRMASS NEAR THE
SURFACE APPEARS TO BE TOO DRY FOR ANY FOG SATURDAY MORNING. DEWPOINTS
IN THE TEENS EARLY TONIGHT REBOUND TO THE 20S AFTER MIDNIGHT BUT
STILL TOO LOW FOR FOG DEVELOPMENT.
EXTENDED AVIATION OUTLOOK...MOISTURE ASSOCIATED WITH AN ONSHORE
FLOW MAY HELP CAUSE PERIODS OF MVFR CONDITIONS SATURDAY AND IFR
TO MVFR CONDITIONS SUNDAY THROUGH TUESDAY...MAINLY DURING THE EARLY
MORNING HOURS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1239 PM EST FRI NOV 18 2011
.SYNOPSIS...
HIGH PRESSURE WILL DOMINATE THE WEATHER OVER THE AREA THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. LOW LEVEL EASTERLY FLOW MAY INCREASE
LOW CLOUDS OVER THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
DRY HIGH PRESSURE CENTERED OVER NORTH CAROLINA WILL DOMINATE
TODAY. THE LATEST SATELLITE TRENDS AND THE MODELS INDICATED
CONTINUED CLEAR SKIES. THE TEMPERATURE GUIDANCE WAS CONSISTENT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
DRY RIDGING SHOULD CONTINUE TO DOMINATE TONIGHT. PRECIPITABLE
WATER VALUES WILL BE EXTREMELY LOW...LESS THAN A QUARTER INCH. EXPECT
LOWS IN THE UPPER 20S TO LOWER 30S UNDER STRONG RADIATIONAL
COOLING CONDITIONS. ONE POTENTIAL FLY IN THE OINTMENT OVERNIGHT
WILL BE THE POSSIBILITY OF STRATOCUMULUS MOVING IN OFF THE COAST
AS THE LOW LEVEL FLOW SHIFTS MORE SOUTHERLY ALLOWING ATLANTIC
MOISTURE TO OVERSPREAD THE REGION.
BY SATURDAY THE AIR MASS BEGINS TO MODIFY AND SURFACE HIGH PRESSURE
SHIFTS OFF THE COAST ALLOWING FOR A RETURN SOUTHERLY FLOW. UPPER
HEIGHTS WILL ALSO BE RISING IN RESPONSE TO TROUGHING UPSTREAM OVER
THE WESTERN PART OF THE COUNTRY. MAX TEMPERATURES SHOULD RISE BACK
INTO THE 60S SATURDAY AFTERNOON DESPITE SOME POSSIBLE CLOUD COVER.
LOW LEVEL FLOW OFF THE ATLANTIC WILL CONTINUE TO INCREASE
ATMOSPHERIC MOISTURE AS PRECIPITABLE WATER VALUES RETURN TO NEAR 1
INCH BY SUNDAY MORNING. PRE-DAWN STRATUS EARLY SUNDAY WILL LIMIT
THE AMOUNT OF COOLING AND THEREFORE EXPECT WARMER MIN TEMPERATURES
SATURDAY NIGHT. CONTINUED WARMING ON SUNDAY AS HIGHS PUSH INTO THE
LOWER 70S WITH WARM ADVECTION.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED MONDAY AND TUESDAY AS
UPPER HEIGHTS RISE AND SOUTHERLY FLOW AROUND THE SURFACE HIGH
BRINGS WARMER AIR NORTHWARD. TIMING FOR ANOTHER COLD FRONT
CROSSING THE AREA LOOKS TO BE TUESDAY NIGHT INTO WEDNESDAY
MORNING BRINGING THE NEXT CHANCE OF PRECIPITATION. FOR NOW POPS
WILL BE IN THE LOW CHANCE RANGE WITH THE FRONTAL PASSAGE. COLD
HIGH PRESSURE BUILDS INTO THE AREA BEHIND THE FRONT THURSDAY
PROVIDING DRY WEATHER AND BELOW NORMAL TEMPERATURES.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL MOVE EAST THIS EVENING. THIS WILL ALLOW 2 KFT
WINDS TO THE SOUTHEAST AND ADVECT MOISTURE INTO THE REGION LATE
TONIGHT AFTER MIDNIGHT. WILL KEEP MAINLY VFR CONDITIONS OVERNIGHT
AS AIRMASS REMAINS TO BE DRY. BOTH NAM AND RUC SHOW SOUTHEAST WINDS
BRINGING MOISTURE IN THE FORM OF CLOUDS AFTER MIDNIGHT. WILL KEEP
CLOUDS SCATTERED NEAR 2 KFT 06Z SOUTH LIKE AGS AND OGB AND 08Z TAF
SITES NORTH OF THERE. WITH DRY AIR...THINK CEILINGS WILL BE SLOW
TO DEVELOP. SO...DECIDED TO GO JUST SCATTERED UNTIL 12Z-14Z TIME
FRAME. WILL HAVE MVFR CEILINGS SOUTH TAF SITES OF OGB AND AGS
THEN MOVING NORTH TO REMAINING TAF SITES BY 14Z. THERE SHOULD BE
SOME WEAK ISENTROPIC LIFT AS WELL BUT MOIST LAYERS APPEARS TO BE
TOO SHALLOW TO GIVE ANY PRECIPITATION SATURDAY. AIRMASS NEAR THE
SURFACE APPEARS TO BE TOO DRY FOR ANY FOG SATURDAY MORNING. DEWPOINTS
IN THE TEENS EARLY TONIGHT REBOUND TO THE 20S AFTER MIDNIGHT BUT
STILL TOO LOW FOR FOG DEVELOPMENT.
EXTENDED AVIATION OUTLOOK...MOISTURE ASSOCIATED WITH AN ONSHORE
FLOW MAY HELP CAUSE PERIODS OF MVFR CONDITIONS SATURDAY AND IFR
TO MVFR CONDITIONS SUNDAY THROUGH TUESDAY...MAINLY DURING THE EARLY
MORNING HOURS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...07
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1124 AM CST FRI NOV 18 2011
.AVIATION...
VFR WX WILL BE SEEN THROUGH 12Z/19 AND LIKELY 18Z/19. RUC MODEL
INDICATES THE INVERSION MIXING TO ABOUT 3KFT AGL. SOME MOMENTUM
TRANSFER FROM ALOFT IS OCCURRING WHICH IS LIKELY RESULTING IN LOW
LEVEL TURBULENCE DUE TO MIXING. THE INVERSION BEGINS TO RE-
ESTABLISH BY 00Z/19 SO WINDS WL DECREASE AFT 22Z/18. AFT 00Z/19 MODELS
GENERALLY SHOW 30-35 KTS ARND 2KFT AGL WHICH COULD RESULT IN LLWS
BUT SHEAR VALUES ARE MARGINAL ARND 20 KTS. A SCT TO BKN DECK AT
4-6KFT AGL SHOULD DVLP AFT 12Z/19 AS MOISTURE ADVECTS IN.
..08..
&&
.PREV DISCUSSION... /ISSUED 1054 AM CST FRI NOV 18 2011/
UPDATE...
A FAIRLY SUBSTANTIAL UPDATE TO THE FCST HAS BEEN DONE BASED ON
SATELLITE AND SFC OBS TRENDS THROUGH MID MORNING.
A WEAK SHORTWAVE MOVING THROUGH IN THE FLOW ALOFT HAS HELPED
GENERATE OPAQUE CI/CS THAT IS HELPING TO SUPPRESS TEMPERATURES.
RUC TRENDS SHOW THIS SHORTWAVE EXITING THE AREA DURING THE
AFTERNOON SO SKIES WILL EVENTUALLY CLEAR.
THE MORE SUBSTANTIAL CLOUD COVER IS HELPING TO SUPPRESS
TEMPERATURES IN SPITE OF THE WAA THAT IS OCCURRING. RUC TRENDS
NOW INDICATE THE INVERSION ONLY MIXING TO AROUND 900MB. THIS LOWER
MIXING HEIGHT COMBINED WITH MORE CLOUDS WILL RESULT IN
TEMPERATURES BEING A BIT LOWER THAN FCST. ADDITIONALLY...THE LOWER
MIXING HEIGHT WILL NOT MIX DOWN AS MUCH HIGHER MOMENTUM AIR ALOFT.
WINDY CONDITIONS WILL BE SEEN BUT NO HEADLINES APPEAR WARRANTED.
THE MODELS EITHER VERIFIED OR INITIALIZED TOO MOIST IN THE LOWER
LEVELS BASED ON 12Z UA DATA. THIS MOIST BIAS WILL PLAY INTO THE
FCST FOR TONIGHT AND SATURDAY WHICH WILL BE DISCUSSED MORE
THOROUGHLY IN THE AFTERNOON DISCUSSION.
AN UPDATED FCST HAS BEEN SENT.
.08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1054 AM CST FRI NOV 18 2011
.UPDATE...
A FAIRLY SUBSTANTIAL UPDATE TO THE FCST HAS BEEN DONE BASED ON
SATELLITE AND SFC OBS TRENDS THROUGH MID MORNING.
A WEAK SHORTWAVE MOVING THROUGH IN THE FLOW ALOFT HAS HELPED
GENERATE OPAQUE CI/CS THAT IS HELPING TO SUPPRESS TEMPERATURES.
RUC TRENDS SHOW THIS SHORTWAVE EXITING THE AREA DURING THE
AFTERNOON SO SKIES WILL EVENTUALLY CLEAR.
THE MORE SUBSTANTIAL CLOUD COVER IS HELPING TO SUPPRESS
TEMPERATURES IN SPITE OF THE WAA THAT IS OCCURRING. RUC TRENDS
NOW INDICATE THE INVERSION ONLY MIXING TO AROUND 900MB. THIS LOWER
MIXING HEIGHT COMBINED WITH MORE CLOUDS WILL RESULT IN
TEMPERATURES BEING A BIT LOWER THAN FCST. ADDITIONALLY...THE LOWER
MIXING HEIGHT WILL NOT MIX DOWN AS MUCH HIGHER MOMENTUM AIR ALOFT.
WINDY CONDITIONS WILL BE SEEN BUT NO HEADLINES APPEAR WARRANTED.
THE MODELS EITHER VERIFIED OR INITIALIZED TOO MOIST IN THE LOWER
LEVELS BASED ON 12Z UA DATA. THIS MOIST BIAS WILL PLAY INTO THE
FCST FOR TONIGHT AND SATURDAY WHICH WILL BE DISCUSSED MORE
THOROUGHLY IN THE AFTERNOON DISCUSSION.
AN UPDATED FCST HAS BEEN SENT.
..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EST FRI NOV 18 2011
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS
THE CONUS. SEVERAL WEAK SHORTWAVES WERE EMBEDDED IN THE WRLY FLOW
OVER THE NRN PLAINS AND ADJOINING PORTIONS OF SRN CANADA. A STRONGER
UPPER LEVEL JET AND SHORTWAVE TROUGH THAT WILL IMPACT WEATHER
SATURDAY WAS MOVING INTO THE PAC NW. RADAR RETURNS OVER NRN WI AND
SW UPPER MI WERE INCREASING AS WAA AND ISENTROPIC ASCENT INCREASED
AHEAD OF A SFC TROUGH OVER THE PLAINS. SFC OBS INDICATED THAT THE
PCPN WAS MAINLY ALOFT.
&&
.DISCUSSION...
TODAY AND TONIGHT...THE NAM/GFS SHOW A BAND OF 285-295K ISENTROPIC
LIFT MOVING ACROSS UPPER MI. HOWEVER...THE NAM DEPICTION OF
SLOWER/LESS SATURATION IN THE LOWER LEVELS (BELOW 850 MB) LOOKS MORE
REALISTIC GIVEN UPSTREAM OBS/SOUNDINGS. SO...EXPECT ANY PCPN WILL
BE MORE LIGHT/PATCHY AND ONLY SLIGHT CHANCE TO CHANCE POPS WERE
INCLUDED. AS ANOTHER WEAK SHORTWAVE AND ASSOCIATED AREA OF 700-600 MB
FGEN MOVES INTO WRN LAKE SUPERIOR AND WRN UPPER MI LATE TODAY AND
THIS EVENING...SOME PATCHY LIGHT SNOW OR FLURRIES MAY ALSO PERSIST
INTO THE FAR WEST.
SATURDAY AND SATURDAY NIGHT...A FAST MOVING WAVE IS EXPECTED TO MOVE
FROM THE CENTRAL PLAINS SATURDAY MORNING TO NEAR THE STRAITS BY LATE
SATURDAY EVENING. THE GFS/NAM/ECMWF WERE IN REASONABLE AGREEMENT
WITH THE TRACK OF THE SFC LOW. HOWEVER...SINCE THERE HAS
BEEN SIGNIFICANT VARIATION WITH THE POSITION/STRENGTH OF THE
STRONGEST 800-600 MB FGEN AND THE STRUCTURE/PLACEMENT OF THE COUPLED
UPPER LEVEL JET...CONFIDENCE IN WHERE ANY HEAVY BANDS OF SNOW WILL
SET UP IS LIMITED. MODELS CONSENSUS STILL SUGGESTS THE STRONGER
DYNAMICS WILL AFFECT THE WEST HALF OF UPPER MI. SYNOPTIC QPF AMOUNTS
OF 0.25 TO 0.50 INCH STILL SEEM REASONABLE GIVEN 4 G/KG MOISTURE
AVBL AND THE PERIOD OF STRONG FORCING. SNOW/WATER RATIO VALUES ARE
LIKELY TO REMAIN NEAR OR EVEN BELOW 10/1 WITH THE STRONGER UPWARD
MOTION BELOW THE -12C TO -15C LAYER. ADDITIONAL UPSLOPE AND LAKE
ENHANCEMENT IS EXPECTED NEAR IWD AND OVER N CNTRL UPPER MI.
HOWEVER...THE WINDOW FOR HEAVIER SNOW DURING THE PERIOD OF SYNOPTIC
FORCING IS RELATIVELY SHORT. GIVEN THE AMOUNT OF UNCERTAINTY AND WITH
OVERALL SNOWFALL AMOUNTS EXPECTED TO REMAIN MAINLY IN THE 3 TO 7
INCH RANGE BTWN 18Z SAT AND 12Z SUN AN SPS RATHER THAN A WATCH WAS
ISSUED. A NAM/GFS BLEND OF LOW LEVEL THICKNESS/WET BULB ZERO HEIGHTS
WERE USED FOR PLACEMENT OF THE RAIN SNOW LINE FROM ABOUT KP53 TO JUST
SE OF KIMT.
SUNDAY....N TO NNW WINDS 850 MB TEMP TO AROUND -11C SHOULD KEEP SOME
SCT -SHSN GOING IN THE MORNING. AS THE SFC RIDGE BUILDS INTO THE
AREA IN THE AFTERNOON ALONG WITH DRIER AIR AND LOWER INVERSION
HEIGHTS...ANY REMAINING LES WILL TAPER OFF.
FOR THE EXTENDED...SFC TROUGH SLIDES ACROSS MAINLY LK SUPERIOR ON
MONDAY LEADING TO WARM AIR ADVECTION ALOFT AND SOME ISENTROPIC LIFT.
GFS/CANADIAN FAVOR A PERIOD OF LGT SNOW MONDAY BUT FOR MOST PART THE
ECMWF REMAINS DRY. GFS FCST SOUNDINGS SHOW DEEP MOISTURE AND LIFT
ACTING UPON FAVORABLE TEMPS FOR SNOW INITIATION...SO AT LEAST THE
GFS QPF IS CONSISTENT WITH ITS OTHER MODEL FIELDS. SHORTWAVE IS FCST
TO TRACK MAINLY ACROSS LK SUPERIOR AND WOULD EXPECT GREATEST CHANCE
OF SATURATION/PCPN TO OCCUR THERE AS WELL. ONLY HAVE CHANCE POPS ON
THE KEWEENAW. EVEN IF GFS IS CORRECT...WOULD ONLY SEE SUB ADVY SNOW
AMOUNTS...AND THAT IS PRETTY GENEROUS. AFTER TROUGH EXITS...LOOKS
LIKE A QUIET PERIOD OF WEATHER OVR UPR LAKES LEADING INTO THE
THANKSGIVING HOLIDAY AS WRLY FLOW KEEPS MAIN STORM TRACK SUPPRESSED
TO SOUTH. MAY BE A SYSTEM THAT AFFECTS LOWER MICHIGAN LATER TUESDAY
INTO TUESDAY NIGHT...BUT THAT SHOULD BE GONE BY THE BUSY WEDNESDAY
TRAVEL DAY WITH HIGH PRESSURE BUILDING OVR UPR LAKES REGION.
SEEMS LIKE NICE WARMUP COULD OCCUR ON THANKSGIVING ONCE THE HIGH
MOVES EAST LEADING TO RETURN SW FLOW AT SFC. GFS SOUNDINGS SHOW
LOWER INVERSION BUT EVEN LIMITED MIXING YIELDS HIGHS WELL INTO THE
40S. GIVEN THE SW WINDS...INCREASED TEMPS FOR DOWNSLOPE AREAS NEAR
LK SUPERIOR TOWARD 50 DEGREES...CLOSER TO BIAS CORRECTED CONSENSUS.
LOOKS LIKE VERY NICE WEATHER FOR THE THANKSGIVING HOLIDAY...AND
LIKELY INTO FRIDAY TOO AS SW WINDS CONTINUE TO PUSH WARM AIR INTO
THE UPR LAKES AHEAD OF DEVELOPING TROUGH OVR THE PLAINS. RECORD
HIGHS FOR 24-25 NOVEMBER ARE MAINLY IN THE MID TO UPR 50S ACROSS THE
CWA.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING AT ALL SITES. BY
LATE TONIGHT...PASSAGE OF WEAK LOW PRESSURE TROUGH MAY RESULT IN
CIGS BECOMING MVFR AT KIWD AND KCMX.
CONDITIONS WILL DETERIORATE LATE TONIGHT THROUGH SATURDAY AS A LOW
PRESSURE SYSTEM MOVES SOUTHEAST OF THE AREA. WIDESPREAD IFR/LIFR
CONDITIONS ARE EXPECTED BEGINNING SATURDAY AFTN AT ALL THREE TAF
SITES AS WIDESPREAD/STEADY WET SNOW WORKS ACROSS MOST OF UPPER
MICHIGAN. CONDITIONS WILL NOT IMPROVE UNTIL SUNDAY MORNING AS THE
LOW MOVES AWAY FROM THE AREA.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
WEST-TO-EAST ORIENTED SFC TROUGH PASSES ACROSS LK SUPERIOR TODAY
LEADING TO DEVELOPING SE WINDS OVR WESTERN LK AND GUSTY SOUTHERLY
WINDS TO 30 KTS OVER EASTERN SECTIONS. WINDS DIMINISH TONIGHT...THEN
INCREASE BY LATE SATURDAY WITH ARRIVAL OF LOW PRESSURE SYSTEM FM THE
SOUTHERN PLAINS. SFC LOW NOT FCST TO DEEPEN SIGNIFICANTLY BUT THERE
IS DECENT COLD AIR RUSHING IN FM THE NORTH IN WAKE OF THE SYSTEM.
CANNOT RULE OUT LOW END NORTHERLY GALES SATURDAY NIGHT OVER CNTRL LK
SUPERIOR. NOT NEAR ENOUGH CONFIDENCE TO ISSUE GALE WATCH AT THIS
POINT THOUGH. SHOULD BE A WIDESPREAD SNOW OVER MOST OF LK SUPERIOR
AS THE LOW MOVES THROUGH THE AREA. LOW THEN QUICKLY SLIDES EAST
SUNDAY AND WINDS DIMINISH BY SUNDAY AFTN. WINDS SHOULD STAY LESS
THAN 25 KTS EARLY NEXT WEEK AS A WEAK TROUGH MOVES ACROSS FOLLOWED
BY A LARGE AREA OF HIGH PRESSURE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
DISCUSSION...JLB
AVIATION...TITUS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1037 AM CST FRI NOV 18 2011
.DISCUSSION...
MAIN CHANGE FOR THE MORNING UPDATE WAS TO ADD SOME LOW POPS TO THE
SOUTHEASTERN COUNTIES. RADAR RETURNS HAVE BEEN ONGOING FROM SOUTH
CENTRAL ND INTO THE PARK RAPIDS AREA. HOWEVER...DEWPOINT
DEPRESSIONS ARE STILL LARGE AND NOTHING IS REACHING THE GROUND.
NAM HAS COME MORE INTO LINE WITH THE 06Z GFS...PRODUCING SOME QPF
THIS AFTERNOON OVER OUR SOUTHEASTERN COUNTIES. THE RUC AND HRRR
ALSO START TO SHOW A LITTLE BIT OF ACCUMULATING PRECIP. THINK THAT
IT WILL TAKE A WHILE TO SATURATE DOWN...BUT MODEL SOUNDINGS HAVE
THE LOWER LEVEL RH VALUES INCREASING DURING THE 18-21Z TIME FRAME.
INCLUDED SOME LOW POPS FOR RAIN OR SNOW SHOWERS IN OUR SOUTHEAST.
ALSO INCREASED CLOUDS AND DECREASED AFTERNOON TEMPERATURES A BIT.
&&
.AVIATION...
CONDITIONS WILL REMAIN VFR FOR THE NEXT FEW HOURS...BUT MVFR
CEILINGS WILL MOVE INTO KDVL BY 18Z OR SO. BORDERLINE VFR/MVFR
CEILINGS WILL SPREAD EASTWARD THROUGH THE FORECAST AREA LATER
DURING THE AFTERNOON AND SHOULD BE MVFR INTO TONIGHT. LIGHT AND
VARIABLE WINDS WILL PICK UP OUT OF THE WEST AND NORTHWEST BY THIS
EVENING.
&&
.PREV DISCUSSION... /ISSUED 422 AM CST FRI NOV 18 2011/
SHORT TERM...TODAY THROUGH SUNDAY
PRIMARY FORECAST CHALLENGES INCLUDE CLOUD TRENDS AND TEMPERATURES
TODAY AND THEN SNOW CHANCES AND AMOUNTS THROUGH THE DAY ON
SATURDAY AS A STRONG LOW PRESSURE SYSTEM MOVES ACROSS IOWA. GFS/
NAM/ECMWF/GEM IN GOOD AGREEMENT AND WILL USE A MODEL BLEND FOR
THIS FORECAST PACKAGE.
UPPER LEVEL SHORT-WAVE CURRENTLY ACROSS SOUTHERN SASKATCHEWAN
WILL MOVE ALONG THE INTERNATIONAL BORDER THROUGH THE DAY. THE
SURFACE LOW IS JUST SOUTH OF MINOT AND IS PROGGED TO WEAKEN AND
DROP SOUTHEAST TOWARD MINNEAPOLIS BY 00 UTC TONIGHT. REMAINING
LIGHT SNOW IS EXPECTED TO REMAIN NORTH OF THE CANADIAN BORDER...
ALTHOUGH LATEST MODELS SHOW SOME LIGHT QPF THIS AFTERNOON ACROSS
THE SOUTHEAST FORECAST AREA COINCIDENT WITH TRAILING COLD FRONT.
CROSS SECTIONS SUGGEST FAIRLY DRY LOW-LEVELS SO WILL KEEP FORECAST
DRY FOR NOW...BUT SOMETHING TO WATCH THROUGH THE DAY. BETTER
CHANCE FOR LIGHT SNOW...ALBEIT SLIGHT...WILL BE ACROSS THE DEVILS
LAKE BASIN THIS AFTERNOON AS LOW STRATUS DECK ACROSS SOUTHERN
CANADA CREEPS SOUTHWARD THROUGH THE DAY.
OVERALL...EXPECT FILTERED SUNSHINE TODAY THROUGH MID-HIGH LEVEL
CLOUDS. STRONG COLD AIR ADVECTION WILL ACCOMPANY FRONTAL PASSAGE...
BUT SHOULD OCCUR LATE ENOUGH IN THE DAY FOR HIGH TEMPERATURES TO
STILL REACH THE LOWER 20S IN THE NORTHWEST TO NEAR 40 DEGREES IN
THE FAR SOUTH. COLDER THERMAL PROFILE...HOWEVER...WILL ALLOW
NIGHTTIME LOWS TO DIP INTO THE SINGLE DIGITS ACROSS THE NORTH WHERE
SOME CLEARING IS POSSIBLE TO THE LOW 20S ACROSS THE SOUTH.
ATTENTION THEN TURNS TO SATURDAY AS A STRONG SURFACE LOW EJECTS
FROM EASTERN CO AND INTO SOUTHERN WI 06 UTC SUNDAY. BEST LINKAGE
BETWEEN STRONG 850 TO 700 HPA FRONTOGENESIS AND 500 TO 300 HPA
Q-VECTOR CONVERGENCE WILL BE ALONG A LINE FROM PIERRE TO WATERTOWN
TO ST CLOUD WHERE A SOLID 4 TO 6 INCHES OF SNOW IS POSSIBLE.
FARTHER NORTH ACROSS THE EXTREME SOUTHERN FORECAST AREA...EXPECT 1
TO 3 INCHES OF NEW ACCUMULATION. A WINTER WEATHER ADVISORY MAY BE
NEEDED...BUT WILL LET LATER SHIFTS EVALUATE POSSIBLE HEADLINES.
THERE SHOULD BE A SHARP CUT-OFF IN PRECIPITATION FROM SOUTH TO
NORTH GIVEN NORTHERLY WIND AROUND SOUTHERN ALBERTA HIGH ADVECTING
DRIER AIR INTO THE REGION. FARGO MAY SEE AROUND A HALF INCH WITH
AREAS NORTH OF THE HIGHWAY 200 CORRIDOR SEEING LITTLE TO NO
ACCUMULATION. TEMPERATURES WILL CONTINUE TO FALL ON SATURDAY WITH
REINFORCING SHOTS OF COLD AIR. HIGHS WILL TOP OUT IN THE LOWER
TEENS TO LOWER 20S.
REMAINING SNOW WILL MOVE OUT OF THE REGION SATURDAY NIGHT...
ALLOWING FOR A DRY SUNDAY WITH INCREASING SUNSHINE. IF ENOUGH
CLEARING OCCURS EARLY IN THE DAY...MORNING LOWS WILL DROP INTO THE
SINGLE DIGITS BELOW ZERO IN SOME PLACES. HIGHS WILL ONLY CLIMB
INTO THE TEENS TO LOWER 20S.
LONG TERM...SUNDAY NIGHT THROUGH THANKSGIVING
EXPECT DRY WEATHER WITH TEMPS WARMING ABOVE NORMAL BY WED. AN
UPPER RIDGE IS WELL PROGGED BY ALL MODELS...SO EXPECT TEMPS TO
WARM ALONG WITH DRY WEATHER THROUGH AT LEAST THANKSGIVING. NO
MAJOR STORMS ARE ON THE HORIZON FOR THE EXTENDED PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS SPOKANE WA
302 PM PST Fri Nov 18 2011
.SYNOPSIS...
Scattered clusters of heavy snow showers will continue to impact
most of eastern Washington and north Idaho through tonight ahead
of an arctic boundary moving in from the Northeast. As the front
moves through...drier and cooler weather is expected with the
largest threat of snow moving into southeast Washington and north
central Idaho on Saturday. Following a break in the weather
Sunday, unsettled weather will return for most of next week with
most of the snow expected to occur near the cascades and northern
mountains.
&&
.DISCUSSION...
Tonight...difficult forecast scenario continues to unfold late this
afternoon as a two distinct air masses remain fixed over the
Inland Northwest between a weakening frontal occlusion. Based on
surface wind directions...the front extended approximately from
the Coulee City area south toward the central Idaho Panhandle.
North of this boundary was a shallow..yet well defined arctic air-
mass with persistent snows extending from the Okanogan Highlands
east toward Sandpoint. Cloud tops in this region have warmed
considerably from this morning and we expect snow rates to ramp
down as well as much drier air works in below 850 mbs. There is
already evidence of this down the Purcell Trench as both Bonners
Ferry and Coeur d`Alene have seen their dewpoints plunge into the
upper teens. Farther west...the drier air will be slower to move
in so...we will extend the winter highlights for the NE Washington
mountains and Okanogan Highlands into the evening and mention
another 1-2" of snow possible.
South of the frontal occlusion...the atmosphere was very unstable for
this time of year. We continue to see showers develop over Adams
and Whitman counties with 45-50dbz which suggests the presence of
intense precipitation which was likely a mix of rain...snow...and
graupel. This activity will will continue to track to the
northeast...hitting southern portions of Spokane County...the
northern Palouse ...and western Columbia Basin. We would expect
this activity to dwindle some as the frontal occlusion weakens and
the potential instability begins to wane with the setting sun.
However any small ripple in the upper atmosphere will provide the
needed lift to generate a new batch of showers.
The toughest part of the forecast is what to do in the region between
the two air masses...i.e. Spokane and Coeur d`Alene area. The NAM
solution and even the GFS both suggest along the leading edge of
the arctic boundary we should be seeing some intense snow based on
a deep frontal lifting and a saturated dendritic layer. However
the radar is telling a different story. The latest HRRR solution
though does mesh with the current radar and really downplays the
GFS and NAM scenario. Thus we still expect we will see some snow
develop late this afternoon and early this evening...but it should
be significantly lighter than the .25" of liquid forecast by the
NAM. If the .25" were to develop between Spokane and Coeur d`Alene
we would see up to 3" of snow or more. However based on road temps
warmer than 35-40 and air temps still above freezing...at least
below 2000 feet it may have a hard time accumulating to that
depth. We will hold onto some light snow accumulations into the
evening...but based on the small accumulations...we will get rid
of the winter storm warnings and cover any localized situations
via short term forecasts. Once the arctic airmass passes
through...the threat of significant snowfall will taper off
rapidly. How far south and west the front gets tonight is tough to
determine...but we suspect it won`t drop into our southeast zones
until tomorrow morning. fx
Saturday through Sunday night: Overall, the forecast will begin
to trend drier from north to south as the cooler modified
Canadian air spills into the Inland NW. This will make for a brisk
breezy day for most locations north of Interstate 90 but little in
the way of snowfall. Further south, we will be monitoring one more
midlevel disturbance (vort lobe) that will skirt southern WA and
the Idaho Panhandle on Saturday keeping the potential for isolated
to scattered light snow showers throughout the day Saturday. This
feature will drop into the region from the northern tip of
Vancouver Island reaching the Cascades and southwestern Basin
Saturday morning then Blues...Palouse...and Camas Prairie Saturday
afternoon. The air mass will remain conditionally unstable with
modeled 700-500mb lapse rates remaining within the 7.5-8.5 C/km
range. While QPF amounts are suggested to be just a few
hundredths, the convective nature to the showers may lead to a
quick inch anywhere from Plain...along the extreme southern
Columbia Basin...Palouse... Blues Mtns...and potions of the Idaho
Panhandle mainly south of I-90. Temperatures will be well below
normal with highs only climbing into the 20`s to mid 30`s with
teens in the northern mountains. With little warming on Saturday
and fresh snow cover across most northern valleys, overnight lows
will be falling into the cold to very cold category. Winds will be
weakening but there is some uncertainty on the amount of clearing
aloft and potential for fog. The northwestern quadrant of the CWA
look to have the highest potential for clearing skies so adjusted
low temperatures well below model guidance for locations in the
Methow Valley, East Slopes, and Okanogan Country where single
digits to below zero. This may also be the case for the valleys of
northeastern WA and northern ID but with models hanging on to some
cloudiness...opted to only go single digits. If skies clear, it is
almost a given that locations like Deer Park, Priest Lake,
Sandpoint, Rathdrum, and Bonners Ferry will dip below zero due to
the fresh snow that has fallen. /sb
Monday through Friday: A warm front will move across the inland
northwest Monday afternoon. Strong southwesterly winds will usher
in some warmer 850 mb temperatures. Precipitation will start off
as snow Monday morning, and then by afternoon snow will change
over to rain across the basin, palouse and portions of the
Spokane/COE areas. Tuesday we continue the moist southwest flow
with showers continuing. Warmer air will continue to move north
so that all valleys will see rain or a rain/snow mix. An upper level
trough will approach the west coast Wednesday. Models start to
diverge on where to point the moisture as the trough digs off
southern California. The 12z ECMWF did trend toward the 12z GFS,
but it still remains faster, though not as fast as the Canadian.
Given the highly active weather pattern through the entire
extended forecast, kept chance of precipitation above climatology.
Monday temperatures start out at or below climatology, but as the
warmer air moves in late Monday temperatures will rise to at or
slightly above climatology through the remainder of the forecast.
/Nisbet
&&
.AVIATION...
18Z TAFs...Cold, unstable air mass setting up over Eastern WA and
Northern ID will continue to fuel snow showers through this evening.
The most organized snow shower activity will focus from KOMK to KCOE
along an approaching frontal boundary sagging in from the N/NE. A
midlevel wave dropping SE along this boundary is expected to
re-organize snow bands over the Spokane-Coeur D Alene corridor arnd
22z-02z. Aft 02z...a shallow cold front should slide into KGEG
strengthening NE flow and bring brief low-level drying. This
appears to be short-lived as another surge of moisture and warmer
air approaches from the SW strengthening low-level inversions and
potential for incr MVFR cigs aft 12z along with -SHSN at KEAT.
Otherwise -SHSN will be more hit or miss for KPUW and KLWS/KMWH
with the biggest concern being the present ifr fog and stratus which
should gradually lift into mvfr stratus or better this aftn. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 20 26 12 29 15 37 / 80 20 20 10 10 30
Coeur d`Alene 20 25 12 29 13 37 / 90 20 20 10 10 40
Pullman 22 29 17 32 16 37 / 70 40 20 10 10 20
Lewiston 29 35 22 37 25 44 / 50 50 20 10 10 20
Colville 15 25 9 28 12 33 / 50 10 10 10 20 60
Sandpoint 17 22 9 28 11 35 / 60 10 20 20 20 60
Kellogg 20 23 15 27 14 33 / 90 30 20 20 10 50
Moses Lake 19 32 10 32 17 37 / 20 30 10 10 10 30
Wenatchee 24 32 13 32 23 35 / 20 40 10 10 30 40
Omak 16 28 4 32 14 33 / 20 20 10 10 30 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Warning until 10 PM PST this evening for Central
Panhandle Mountains-Northern Panhandle.
WA...Winter Storm Warning until 10 PM PST this evening for
Northeast Mountains
Winter Weather Advisory until 10 PM PST this evening for
Okanogan Highlands.
&&
$$