Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/29/12
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
339 PM MST TUE NOV 27 2012
.SHORT TERM...RIDGE AXIS ACROSS WESTERN UTAH WITH MODERATE WEST
TO NORTHWEST FLOW ALOFT OVER COLORADO. WINDS STILL A BIT GUSTY
ACROSS MOUNTAINS AND FOOTHILLS THOUGH HAVE BEEN SLOWLY DECREASING
DURING THE PAST FEW HOURS. STILL...A RECENT GUST OF 46 MPH NOTED
ON LOVELAND PASS AROUND 12000 FEET. GUSTS WERE REACHING RED FLAG
CRITERIA ACROSS PORTIONS OF THE FOOTHILLS AS WELL AS ACROSS SOUTH
PARK WHERE HUMIDITY READINGS WERE AROUND 10 PERCENT. MODELS SHOW
RIDGE AXIS SHIFTING EAST INTO WESTERN COLORADO DURING THE EVENING
WITH GRADIENT ALOFT GRADUALLY WEAKENING. LATEST RUC CROSS SECTIONS
INDICATING CROSS MOUNTAIN FLOW DECREASING TO AROUND 30 KTS AT
MOUNTAIN TOP. THUS...WINDS TO GRADUALLY DECREASE AS AIRMASS COOLS
AND MIXING BECOMES LIMITED. WILL LET RED FLAG WARNING EXPIRE AT
00Z AS HUMIDITY READINGS WILL BE ON THE INCREASE. OTHERWISE...
SKIES TO BECOME MAINLY CLEAR DURING THE EVENING AS WAVE CLOUD
ALONG URBAN CORRIDOR CONTINUES TO DISSIPATE. WRF SYNTHETIC
SATELLITE IMAGERY SUGGESTING A PORTION OF THE WAVE CLOUD TO
PERSIST OVERNIGHT...BEFORE SHIFTING NORTH. BASED ON LATEST
SATELLITE LOOPS...WRF IMAGERY SEEMS A BIT OVERDONE. ON
WEDNESDAY...BOTH NAM AND GFS SHOW RIDGE AXIS SHIFTING ACROSS
REMAINDER OF COLORADO DURING THE MORNING...WITH THE AXIS ALONG
EASTERN COLORADO BORDER AT 18Z. FLOW ALOFT BECOMES MORE WESTERLY
DURING THE AFTERNOON...ALLOWING THE CROSS MOUNTAIN FLOW TO
INCREASE. LATEST NAM SHOWING THE COMPONENT AT MOUNTAIN TOP AROUND
45 KTS BY 00Z. THOUGH THIS MAY BE A BIT OVERDONE...BREEZY
CONDITIONS TO AGAIN OCCUR ACROSS MOUNTAINS AND ALONG FOOTHILLS AS
WELL AS PARK COUNTY. AIRMASS WILL AGAIN BE DRY WITH LOW HUMIDITY
EAST OF THE CONTINENTAL DIVIDE. APPEARS THAT RED FLAG CONDITIONS
WILL AGAIN BE MET IN SOME AREAS OF THE FOOTHILLS AND PARK
COUNTY. BUT DOES NOT LOOK WIDESPREAD ENOUGH SO WILL HOLD OFF ON
ISSUING A WARNING. TEMPERATURE AND THICKNESS PROGS AS WELL AS
GUIDANCE INDICATING HIGHS IN THE LOWER TO MIDDLE 60S ACROSS THE
PLAINS. CURRENT TEMPERATURE GRIDS IN LINE WITH GUIDANCE AND SEEMS
REASONABLE.
.LONG TERM...MODELS HAVE A WEAK UPPER TROUGH MOVE ACROSS THE CWA
LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING. THURSDAY`S
NORTHWESTERLY FLOW ALOFT IS SHORT LIVED. IT BECOMES ZONAL AND
STAYS THAT WAY INTO THE EXTENDED PERIODS. SPEEDS ARE MODERATE
...MAINLY 50 TO 75 KNOTS THURSDAY THROUGH FRIDAY NIGHT. THE QG
VERTICAL VELOCITY FIELDS CONTINUE TO SHOW BENIGN SYNOPTIC SCALE
ENERGY WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. THE LOW LEVEL
PRESSURE AND WIND FIELDS HAVE A BRIEF SHOT OF DOWNSLOPING WITH THE
UPPER TROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. THEN THE
GRADIENT POINTS TO NORMAL DUIRNAL WIND PATTERNS WITH A BIT OF
DOWNSLOPING MIXED IN THROUGH FRIDAY NIGHT. FOR MOISTURE...THERE IS
SOME...MAINLY IN THE MID AND UPPER LEVELS FROM LATE WEDNESDAY
NIGHT THROUGH FRIDAY NIGHT. THE NAM`S MOISTURE IS A BIT BETTER
THAN THE GFS` IN THE MOUNTAINS...ESPECIALLY THURSDAY MORNING.
MODELS HAVE NO MEASURABLE PRECIPITATION PROGGED ON THE QPF FIELDS
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NO POPS. FOR TEMPERATURES...
THURSDAY AND FRIDAY`S HIGHS LOOK CLOSE TO WEDNESDAY`S. FOR THE
LATER DAYS...SATURDAY THROUGH TUESDAY...MODELS HAVE ZONAL FLOW FOR
THE CWA SATURDAY AND SUNDAY...THEN SOUTHWESTERLY FLOW ALOFT SUNDAY
NIGHT AND MONDAY. AN UPPER TROUGH MOVES ACROSS LATE MONDAY...THEN
STRONG NORTHWESTERLY FLOW ALOFT MONDAY NIGHT AND TUESDAY. THE
TROUGH LOOKS A BIT STRONGER TODAY THAN YESTERDAY. BUT MOISTURE IS
NOT GREAT ON ANY OF THE MODELS. A COLD FRONT MOVES IN MONDAY WITH
THE TROUGH...AND BOTH MONDAY AND TUESDAY`S TEMPERATURES LOOK
CLOSER TO SEASONAL NORMALS...THAN THE WARM SATURDAY AND SUNDAY
HIGHS DO. WILL GO WITH MINOR ALPINE POPS LATE SUNDAY NIGHT AND
MONDAY...NOTHING FOR THE PLAINS ALL FOUR DAYS.
&&
.AVIATION...DOWNSLOPE WINDS BEGINNING TO WEAKEN ACROSS AREA WITH
DIA SHOWING MORE OF A SOUTHEAST COMPONENT. WINDS STILL A BIT GUSTY
AT BJC. WINDS TO CONTINUE TO WEAKEN DURING THE EVENING WITH
DRAINAGE PATTERN DEVELOPING BY 03Z. BJC MAY STILL HAVE MORE OF A
WESTERLY COMPONENT OVERNIGHT. ON WEDNESDAY...WEAK SOUTHERLY
GRADIENT EXPECTED ACROSS AREA WITH SOUTHERLY WINDS PREVAILING.
POTENTIAL FOR A WEAK ANTICYCLONE DEVELOPING IN THE DENVER AREA
DURING THE AFTERNOON WINDS MORE OF A SOUTHEAST DIRECTION AT DEN.
SPEEDS AROUND 8 KTS TO PREVAIL...THOUGH SOME GUSTS TO 20 KTS
POSSIBLE AT BJC DURING THE AFTERNOON WITH DOWNSLOPE FLOW. VFR TO
CONTINUE.
&&
.FIRE WEATHER....RED FLAG WARNING TO CONTINUE UNTIL 5 PM MST TODAY
FOR FOOTHILLS AND PARK COUNTY. WINDS STILL GUSTING IN THE 25-30
MPH IN SOME LOCATIONS WITH LOW HUMIDITY. WINDS TO GRADUALLY
DECREASE DURING THE EVENING WITH A SLOW INCREASE IN HUMIDITY. ON
WEDNESDAY...AIRMASS TO REMAIN DRY. BREEZY CONDITIONS AGAIN
EXPECTED ACROSS PORTIONS OF FOOTHILLS AND PARK COUNTY DURING THE
AFTERNOON. DOES NOT LOOK WIDESPREAD TO WARRANT A RED FLAG WARNING.
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ214>216.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1021 AM MST TUE NOV 27 2012
.UPDATE...STRONG WEST TO NORTHWEST FLOW ALOFT CURRENTLY ACROSS
COLORADO. AFTER A BRIEF LULL IN THE WIND GUSTS...SPEEDS BEGINNING
TO INCREASE AGAIN ACROSS MOUNTAINS AND FOOTHILLS OF BOULDER...
LARIMER AND JEFFERSON COUNTIES AS WINDS ALOFT MIXES TO SURFACE.
WITH DRY AIRMASS IN PLACE...THERE WILL BE SUFFICIENT MIXING
THROUGHOUT THE DAY TO KEEP AT LEAST BREEZY CONDITIONS CONTINUING
ACROSS MOUNTAINS AND FOOTHILLS. RUC CROSS SECTIONS SHOW CROSS
MOUNTAIN FLOW OF AROUND 55 KTS AT MOUNTAIN TOP THROUGH
18Z...DECREASING TO AROUND 45 KTS AT 20Z. THUS WILL PROBABLY SEE
THE STRONGEST WINDS OCCURRING IN THIS TIME FRAME...BUT NOT
EXPECTING WINDS TO REACH HIGH WIND CRITERIA AT THIS TIME.
STILL...GUSTY DOWNSLOPE WINDS TO KEEP HUMIDITY READINGS LOW WHICH
WILL ENHANCE FIRE DANGER ALONG FOOTHILLS. RED FLAG WARNING ALREADY
IN PLACE FOR THE FOOTHILLS AND PARK COUNTY WHICH STILL LOOKS
REASONABLE. OVERALL...CURRENT FORECASTS LOOK ON TRACK...BUT WILL
PROBABLY NEED TO INCREASE WINDS A BIT ACROSS THE MOUNTAINS AND
FOOTHILLS. WAVE CLOUD ALONG URBAN CORRIDOR MAY SLOW THE EXPECTED
WARMUP...BUT ONLY BY A FEW DEGREES AS DOWNSLOPE WARMING SHOULD
OFFSET THE SLOW WARMING.
&&
.AVIATION...DOWNSLOPE PATTERN IN PLACE WITH DRAINAGE FLOW
ENHANCED. LATEST RUC SHOWING WINDS BECOMING NORTHWEST AT DEN AND
APA BY 20Z WHILE REMAINING WESTERLY AT BJC. BUT RUC ALSO INDICATES
THE POTENTIAL FOR A WEAK ANTICYCLONE DEVELOPING OVER DENVER AREA
BY 22Z WITH WIND AT DEN SHIFTING TO THE NORTHEAST. WITH THE
DOWNSLOPE FLOW AND MIXING EXPECTED...NOT SURE ABOUT THE
ANTICYCLONE. FOR NOW WILL CONTINUE WITH THE CURRENT TAF TRENDS.
&&
.FIRE WEATHER...RED FLAG WARNING IN EFFECT FOR FOOTHILLS AND PARK
COUNTY. HUMIDITY READINGS ALREADY MEETING OR GETTING CLOSE TO
CRITERIA. WINDS ALSO ON THE INCREASE. CONDITIONS TO CONTINUE
THROUGH THE DAY...BEFORE WINDS BEGIN TO DECREASE. A FEW LOCATIONS
ALONG URBAN CORRIDOR COULD REACH CRITERIA FOR A SHORT TIME...
MAINLY NEAR THE FOOTHILLS AND NEAR THE WYOMING BORDER. BUT
CONDITIONS DON`T APPEAR WIDESPREAD ENOUGH ACROSS URBAN CORRIDOR FOR
ANY RED FLAG HILITES.
&&
.PREV DISCUSSION... /ISSUED 311 AM MST TUE NOV 27 2012/
SHORT TERM...SEEMS AS WE HAVE ALREADY SEEN OUR MINIMUM
TEMPERATURES IN MOST PLACES EARLIER IN THE NIGHT/EARLY MORNING AS
WARMER TEMPERATURES MOVE IN UNDER A DRY UPPER RIDGE BUILDING
OVERHEAD. DRY DEWPOINTS ARE ALSO MOVING IN...WITH READINGS OF -10
TO -20 DEGREES F OVER THE HIGH MOUNTAINS. THESE DRY DEW POINTS
HAVE CAUSED HUMIDITIES TO PLUMMET OVER THE MOUNTAINS AND HIGHER
FOOTHILLS INTO THE TEENS TO 30 PERCENT RANGE ALREADY. WITH BREEZY
DOWNSLOPE WINDS BEING ENHANCED OVER THE EASTERN SLOPES OF THE
MOUNTAINS AND HIGHER FOOTHILLS DUE TO A SURFACE LOW DEEPENING OVER
THE PLAINS....FIRE DANGER CONCERNS HAVE INCREASED WITH HUMIDITIES
EXPECTED TO DROP FURTHER. THEREFORE WILL BE ISSUING A RED FLAG
WARNING FOR THE FOOTHILL ZONES AS WELL AS SOUTH PARK DUE TO DRIER
HUMIDITIES EXPECTED THERE COMPARED TO THE HIGH VALLEYS FURTHER
NORTH.
WITH YESTERDAYS POST COLD FRONTAL AIRMASS WASHED OUT BY THE WARMER
AND DRIER AIR DOWNSLOPING IN...TEMPERATURES TODAY WILL BE MUCH
WARMER WITH HIGHS NEAR 60 FOR THE PLAINS AND IN THE 40S FOR THE
MOUNTAINS. NO CHANCE FOR PRECIPITATION AS MOISTURE IS MEAGER AT
BEST...HOWEVER MAY SEE A FEW WAVE CLOUDS AS A BIT OF UPPER LEVEL
MOISTURE MOVES SOUTHEAST OUT OF WYOMING.
LONG TERM...UPPER LEVEL RIDGING WILL PERSIST OVER THE CENTRAL AND
SOUTHERN ROCKIES THROUGH THE WEEKEND AS A DEEP UPPER TROUGH
REMAINS OVER THE EASTERN PACIFIC. THERE SHOULD ONLY BE A COUPLE
WEAK RIPPLES MOVING THROUGH THE AREA...ONE LATE WEDNESDAY NIGHT/
THURSDAY MORNING AND ANOTHER BY FRIDAY NIGHT/SATURDAY. HOWEVER...
THEY WILL LIKELY BRING JUST A FEW MID/HIGH CLOUDS WITH LITTLE IF
ANY COOLING. THE FRIDAY NIGHT/SATURDAY WAVE MAY HAVE JUST ENOUGH
MOISTURE LEFT TO PROVIDE A SLIGHT CHANCE OF SHOWERS IN THE FAR
NORTHERN MOUNTAINS.
AS A RESULT OF THE ABOVE MENTIONED PATTERN AND PERSISTENT WESTERLY
FLOW...LOOK FOR MUCH ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH
THIS WEEKEND. WITH 700 MB TEMPERATURES ADVERTISED TO REACH THE
6-9C RANGE BY SUNDAY...WE HAVE POTENTIAL TO APPROACH RECORD HIGHS
IN THE LOWER TO MID 70S BY THEN. OF COURSE THAT WILL ALL DEPEND
ON AMOUNT OF SUNSHINE AND DOWNSLOPE WARMING...BUT ENOUGH FACTORS
COMING TOGETHER TO WARRANT A WARMER FORECAST. FIRE DANGER CONCERNS
WILL ALSO INCREASE WITH THE WARMER TEMPERATURES AND POTENTIAL FOR
STRONGER DOWNSLOPE WINDS THIS WEEKEND.
LATEST ECMWF AND GFS ENSEMBLES FINALLY SHOW A LITTLE MORE
PRONOUNCED UPPER TROUGH REACHING THE AREA EARLY NEXT WEEK. HAVE
INCLUDED A LOW CHANCE OF SNOW SHOWERS REACHING THE MOUNTAINS BY
MONDAY.
FIRE WEATHER...ISSUING A RED FLAG WARNING DUE TO BREEZY
DOWNSLOPING WINDS OVER THE EASTERN SLOPES OF THE FRONT RANGE
MOUNTAINS AS WELL AS THE MOSQUITO RANGE AND INTO THE HIGHER
FOOTHILLS. FUELS ARE LISTED AS NOT SUSCEPTIBLE IN THE MOUNTAINS
ABOVE 9000 FEET...SO WILL LIMIT THE WARNING TO THE FOOTHILLS AND
SOUTH PARK DUE TO CONDITIONS EXPECTED TO BE MET NEAR FAIRPLAY.
GUSTS OF 30 TO 45 MPH CAN BE EXPECTED WITH HUMIDITIES NEAR 10
PERCENT. SOME AREAS ARE ALREADY HITTING CRITERIA THIS
MORNING...BUT WILL DELAY THE START UNTIL 9 AM AS THE WINDS MAY
HAVE A LULL BEFORE PICKING UP AGAIN LATE MORNING.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. DRAINAGE
WINDS THIS MORNING WILL TAKE ON MORE OF A WESTERLY COMPONENT THIS
AFTERNOON ESPECIALLY OVER KBJC AND KDEN...WHEREAS KAPA MAY STAY
LIGHT AND VARIABLE WITH A BIT OF A SOUTHEAST DIRECTION THIS
AFTERNOON. KBJC MAY SEE SOME GUSTS UP TO 20 KTS WITH A BIT OF A
DOWNSLOPE PATTERN IN EFFECT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ214>216.
&&
$$
SHORT TERM...D-L
LONG TERM....BARJENBRUCH
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
146 AM MST TUE NOV 27 2012
.AVIATION...
UPDATED KDEN AND KAPA TAFS AS IT LOOKS LIKE WINDS WILL HAVE A
MORE WESTERLY COMPONENT STRETCHING OUT OF THE FOOTHILLS OVER
KDEN...WITH LIGHTER WINDS OVER KAPA. NO CHANGE TO KBJC. VFR
CONDITIONS EXPECTED THROUGH TONIGHT. POTENTIAL STILL EXISTS FOR
MOUNTAIN WAVE CLOUD DEVELOPING ALONG FOOTHILLS BETWEEN 11Z AND 15Z
AS AN AREA OF MOISTURE ALOFT CURRENTLY OVER WYOMING MOVES
SOUTHEAST. GUSTS UP TO 20 KTS POSSIBLE AT BJC.
&&
.PREV DISCUSSION... /ISSUED 838 PM MST MON NOV 26 2012/
UPDATE...HAVE UPDATED TO ADJUST MINS OVERNIGHT AS WE HAVE ALREADY
DROPPED AT OR BLO OUR FORECAST MINS IN A COUPLE OF AREAS. COLDEST
READINGS MAY OCCUR PRIOR TO 2 AM WITH SOME MODIFICATION
THEREAFTER ONCE DRAINAGE WINDS KICK IN. MOUNTAIN WAVE OVERNIGHT
MAY ALSO MODIFY THE LOWS OVERNIGHT IN AND NEAR THE FOOTHILLS. A
COUPLE OF POCKETS OF STRATUS STILL OVER EASTERN LARIMER AND
NORTHWEST WELD...AS WELL AS OVER SEDGWICK AND PHILLIPS COUNTIES
THIS EVENING. LOW CLOUDS WILL DIMINISH IN THOSE AREAS AS WELL OVER
THE NEXT FEW HOURS.
AVIATION...VFR CONDITIONS OVERNIGHT. NO SIGNIFICANT CHANGES IN
THE UPCOMING TAFS WITH DRAINAGE WINDS AT KDEN AND KAPA. SOME
MOUNTAIN WAVE ACTIVITY COULD KICK UP THE WINDS NEAR KBJC TOWARDS
12Z...MORE THAN IN THE CURRENT TAF SO SOME ADJUSTMENT MAY BE
NECESSARY AROUND THAT TIME.
PREV DISCUSSION... /ISSUED 313 PM MST MON NOV 26 2012/
SHORT TERM...WEAK SURFACE HIGH SLIDING ACROSS CENTRAL PLAINS
BEHIND THIS MORNING`S COLD FRONT. LOW CLOUDS ACROSS PLAINS STILL
FAIRLY EXTENSIVE BUT BEGINNING TO DISSIPATE EAST OF DENVER. STILL
SOME FOG PERSISTING IN THE FOOTHILLS WEST OF DENVER...ALSO SHOWING
SIGNS OF DISSIPATING. LATEST RUC CONTINUES TO SHOW A SLOW
DISSIPATION OF THE LOW CLOUDS DURING THE EVENING WITH MAINLY CLEAR
SKIES BY MIDNIGHT. THIS LOOKING REASONABLE AS DRIER AIR MOVES INTO
REGION FROM THE WEST. THERE WILL BE SOME INCREASE IN HIGH LEVEL
MOISTURE OVERNIGHT WITH WRF SYNTHETIC SATELLITE IMAGERY SUGGESTING
THE DEVELOPMENT OF A WAVE CLOUD TOWARDS MORNING. WINDS TO INCREASE
AGAIN ACROSS MOUNTAINS AND HIGHER FOOTHILLS AFTER MIDNIGHT AS
NORTHWEST FLOW ALOFT INCREASES. MODELS SHOW CROSS MOUNTAIN FLOW
AROUND 40 KTS AT MOUNTAIN TOP AT MIDNIGHT. SOME GUSTS AROUND 50
MPH POSSIBLE OVERNIGHT ACROSS THE WIND PRONE AREAS AND EXPOSED
SLOPES. OVERNIGHT TEMPERATURES TO BE WARMER NEAR THE FOOTHILLS
WITH COLDER TEMPERATURES IN LOW LYING AREAS OF THE PLAINS. ON
TUESDAY...MODERATE WEST NORTHWEST ALOFT TO PREVAIL AS UPPER RIDGE
BUILDS INTO AREA. GUSTY WINDS WILL CONTINUE ACROSS THE MOUNTAINS
AND FOOTHILLS...EXTENDING INTO THE WESTERN SECTIONS OF THE URBAN
CORRIDOR DURING THE MORNING. SOME GUSTS TO 50 MPH WILL BE POSSIBLE
OVER THE HIGHER EXPOSED AREAS. BY 18Z GRADIENT ACROSS THE PLAINS
AND LOWER FOOTHILLS EXPECTED TO WEAKEN...THUS SHOULD SEE WINDS
DECREASE AS A RESULT. HOWEVER...BREEZY CONDITIONS WILL PERSIST
ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS. MODELS HINT AT WAVE
CLOUD ALONG FOOTHILLS DECREASING DURING THE MORNING...WITH MAINLY
CLEAR SKIES PREVAILING BY AFTERNOON ACROSS THE REGION. AIRMASS
ACROSS PLAINS TO BE MUCH WARMER THAN TODAY WITH HIGHS WARMING INTO
THE MID 50S TO MID 60S. ALSO A SLIGHT WARMUP EXPECTED FOR
MOUNTAINS WITH HIGHS IN THE 40S.
LONG TERM...MODELS HAVE AN UPPER RIDGE MOVING INTO AND OVER THE
FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. FOR THE MOST PART
.ZONAL FLOW WILL COVER THE CWA INTO THURSDAY MORNING. A WEAK
UPPER TROUGH IS PROGGED TO MOVE THROUGH LATER THURSDAY MORNING
.WITH INCREASING NORTHWESTERLY FLOW ALOFT THE REST OF THURSDAY
AND THURSDAY NIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN
SYNOPTIC SCALE ENERGY OVER THE CWA TUESDAY NIGHT THROUGH THURSDAY
NIGHT. NORMAL DIURNAL WIND PATTERNS ARE EXPECTED TUESDAY NIGHT
.WITH DOWNSLOPE WEDNESDAY AND WEDNESDAY NIGHT. A FAIRLY WEAK
GRADIENT IS PROGGED THURSDAY AND THURSDAY NIGHT...SO NORMAL
PATTERNS ARE LIKELY. FOR MOISTURE...THERE IS VERY LITTLE TUESDAY
NIGHT AND WEDNESDAY. BY WEDNESDAY NIGHT SOME MID AN UPPER LEVEL
MOISTURE IS PROGGED TO MOVE IN. THE NAM HAS SOME FAIRLY DEEP
MOISTURE OVER THE MOUNTAINS THURSDAY MORNING AT 12Z...THE GFS HAS
LESS...THE ECMWF WAY LESS. FOR THE REST OF THURSDAY AND THURSDAY
NIGHT...THERE IS A BIT OF UPPER LEVEL MOISTURE PROGGED. THE QPF
FIELDS HAVE NO MEASURABLE PRECIPITATION NOTED THROUGH THE FIVE
PERIODS...WITH THE EXCEPTION OF A TINY BIT OVER THE FAR NORTHWEST
CWA THURSDAY MORNING AT 12Z ON THE NAM. WILL LEAVE POPS OUT FOR
ALL AREAS FOR NOW. FOR TEMPERATURES...WEDENSDAY`S HIGHS LOOK 1-2 C
WARMER THAN TUESDAY`S. THURSDAY`S HIGHS ARE 0-2 C COOLER THAN
WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...MODELS
HAVE WEST-SOUTHWESTERLY FLOW ALOFT...WITH VERY LIMITED MOISTURE.
TEMPERATURES LOOK TO STAY ABOVE SEASONAL NORMALS.
AVIATION...LOW CLOUDS SLOWLY ERODING ACROSS AREA...WITH MVFR
CEILINGS PERSISTING AT BJC AND APA. CLOUDS TO CONTINUE TO ERODE
THROUGH THE EVENING WITH IMPROVING CEILINGS. SHOULD EXPECT VFR
CONDITIONS AT BJC AND APA BY 02Z. VFR CEILINGS TO PREVAIL AT DEN
WITH CEILINGS AROUND 7000 FEET AGL BY 02Z. SKIES TO CLEAR ACROSS
THE AREA AROUND 06Z WITH A GRADUAL INCREASE IN HIGH LEVEL MOISTURE
OVERNIGHT. POTENTIAL FOR MOUNTAIN WAVE CLOUD DEVELOPING ALONG
FOOTHILLS BETWEEN 08Z AND 15Z...SHOULD NOT HAVE MUCH IMPACT ON
AREA AIRPORTS. LIGHT SOUTHEASTERLY WINDS THIS EVENING WITH
DRAINAGE FLOW DEVELOPING BY MIDNIGHT. SPEEDS AROUND 10 KTS
EXPECTED OVERNIGHT...THOUGH GUSTS UP TO 20 KTS POSSIBLE AT BJC.
WINDS TO DECREASE AND BECOME NORTHWEST ACROSS THE AREA BY 18Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RJK
AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
747 AM EST TUE NOV 27 2012
.SYNOPSIS...
WEAK LOW PRESSURE WILL PASS OFF THE SOUTHERN MID ATLANTIC COAST
THIS AFTERNOON...AND THEN SOUTHEAST OF LONG ISLAND TONIGHT WHILE
BEGINNING TO INTENSIFY. HIGH PRESSURE WILL THEN BUILD FROM THE
TENNESSEE VALLEY...AND PASS OFF THE MID ATLANTIC COAST THROUGH
THE END OF THE WEEK. A WEAKENING COLD FRONT WILL TRAVERSE THE AREA
THURSDAY NIGHT OR FRIDAY...WITH CANADIAN HIGH PRESSURE BUILDING
INTO NEW ENGLAND BEHIND IT. THE FRONT WILL STALL NEARBY...AND THEN
LIFT BACK TO THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
VERY TRICKY FORECAST FOR THIS SYSTEM...AND FRAUGHT WITH BUST
POTENTIAL ESPECIALLY FOR NYC METRO AND COASTAL SECTIONS...AS LOW
LEVEL THERMAL PROFILES DRIVE PRECIP TYPE DESPITE THERMAL PROFILES
ALOFT SUPPORTIVE OF SNOW.
SFC TEMPS IN NYC METRO AND ALONG THE COAST ARE IN THE UPPER
30S/LOWER 40S...AND SFC WET BULB TEMPS ARE A COUPLE DEG ABOVE
FREEZING...SO NOW THINK THESE AREAS WILL BE HARD PRESSED TO SEE
ANY SNOW UNTIL PERHAPS TONIGHT. LATEST RUNS OF THE RAP AND 06Z NAM
SUPPORT THIS IDEA AS WELL...THOUGH WE WILL HAVE TO MONITOR EFFECT
OF NORTHERLY INLAND FLOW AND POSSIBLE CORRESPONDING COASTAL FRONT
DEVELOPMENT THAT COULD IMPACT TEMPS.
FROM PREV DISCUSSION...FCST STILL CARRIES MOSTLY SNOW INLAND...
MIXING WITH RAIN IN THE AFTERNOON EXCEPT WELL NORTH/WEST OF NYC
AND IN THE HIGHER ELEVATIONS WHICH SHOULD REMAIN ALL SNOW...WITH
SUB-ADVY AMTS OF 1-2 INCHES. NYC METRO...COASTAL CT AND LONG
ISLAND SHOULD SEE PRIMARILY RAIN...WITH LITTLE IF ANY SNOW
ACCUMULATION. EXPECTING MAINLY LIGHT PRECIP WHICH WOULD PREVENT
ENTIRE COLUMN FROM COOLING AND FORCING A CHANGE BACK TO SNOW
ACROSS THE ENTIRE CWA...BUT HOW THIS WILL PLAY OUT REMAINS
UNCERTAIN...AND IS DEPENDENT ON MESOSCALE FEATURES ESPECIALLY
LATER THIS AFTERNOON AS STRONGER FRONTOGENETIC FORCING SLIDES
ACROSS. IF DYNAMIC COOLING FROM ALOFT VIA THIS FORCING WINS OUT
THEN ACCUMULATING SNOW COULD FALL ACROSS THE ENTIRE CWA...WITH
ADVY LEVEL SNOWS OF 2-3 INCHES INLAND...AND EVEN AN INCH OR TWO
FOR NYC METRO.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
PRECIP WILL CONTINUE INTO THE EVENING. P-TYPE UNCERTAIN PER NEAR
TERM SECTION...AT THE VERY LEAST INCREASING N FLOW HELPING CHANGE
P-TYPE BACK TO ALL SNOW INLAND AND AT LEAST A SNOW/RAIN MIX FOR
NYC METRO AND COASTAL SECTIONS BEFORE ENDING. MAIN ACCUMULATING
SNOWS TONIGHT SHOULD TAKE PLACE OVER INTERIOR SOUTHERN CT...WITH
AN INCH OR SO. LOWS WILL BE IN THE 20S AND 30S...WITH NYC RIGHT
AROUND THE FREEZING MARK.
WED SHOULD BECOME MOSTLY SUNNY WITH A BRISK NW FLOW. HIGH TEMPS
WILL TOP OUT IN THE LOWER AND MID 40S...NEARLY 20 DEG BELOW AVG.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
UPPER TROUGH AXIS IS FORECAST TO BE E OF THE LOCAL AREA BY 00Z THU
WITH ZONAL FLOW BECOMING ESTABLISHED ALOFT THROUGH THE REMAINDER OF
THE WEEK. DRY WEATHER IS EXPECTED WITH HIGH PRES BUILDING TO OUR
S...WITH A WEAKENING COLD FRONT APPROACHING FROM THE N THU NIGHT OR
FRI. TIMING DIFFERENCES BETWEEN THE GFS AND EC DUE TO THE STRENGTH
AND POSITION OF CANADIAN HIGH PRES BUILDING IN BEHIND IT...WHICH
DIFFER DUE TO UPSTREAM SHORTWAVE WHICH WILL EVENTUALLY TRAVERSE THE
LOCAL AREA OVER THE WEEKEND. MOISTURE IS LIMITED...SO WILL KEEP THE
FORECAST DRY AND ONLY INCREASE CLOUDS WITH THE COLD FROPA.
THE FRONT WILL BECOME STATIONARY OVER OR SOUTH OF THE AREA...BUT
WILL DEPEND ON HOW FAR S THE CANADIAN HIGH BUILDS. EC BUILDS FURTHER
S INTO NEW ENGLAND THAN THE GFS AND PUSHES THE FRONT FURTHER S. IT
IS ALSO DRIER THAN THE GFS...BUT THE GENERAL PATTERN IS THE SAME
WHERE THE HIGH SLIDES OFFSHORE AND WAA ENSUES. HAVE NOT DEVIATED
MUCH FROM THE PREVIOUS FORECAST THIS WEEKEND AND INTO EARLY NEXT
WEEK WITH THE DIFFERENCES. HOWEVER...AT THE VERY LEAST IT APPEARS TO
BE CLOUDY DURING MOST OF THIS TIME FRAME.
TEMPS BEGIN BELOW NORMAL ON THU AND FRI...IN THE 40S DURING THE DAY
AND 20S AND 30S AT NIGHT. A WARMING TREND WILL THEN BEGIN ON SAT AND
CONTINUE INTO EARLY NEXT WEEK WITH TEMPERATURES ABOVE CLIMO NORMS.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE REMAINS TO THE SOUTH OF THE TERMINALS TODAY AS IT MOVES
ENE THROUGH TONIGHT.
MODERATE TO HIGH CONFIDENCE IN WINDS. FOR ALL TERMINALS...TIMING OF
ONSET OF PCPN AND ONSET OF LOWERING CIGS/VSBYS MAY BE AN HOUR TWO
OFF. PCPN TYPE AND SNOW ACCUM FORECASTS ARE LOW CONFIDENCE...SEE
COMMENTS BELOW.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: RA COULD PREVAIL AS EARLY AS 15-16Z. SNOW
ACCUMULATION ON RUNWAY OF UP TO AN INCH
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: CHC THAT RA COULD PREVAIL THROUGH THE ENTIRE
DAY WITH JUST PERHAPS A BRIEF PERIOD OF -RASN AT THE ONSET OF PCPN.
SNOW ACCUMULATION ON RUNWAY OF BELOW AN INCH.
KLGA FCSTER COMMENTS: CHC THAT RA COULD PREVAIL THROUGH THE ENTIRE
DAY WITH JUST PERHAPS A BRIEF PERIOD OF -RASN AT THE ONSET OF PCPN.
SNOW ACCUMULATION ON RUNWAY OF BELOW AN INCH.
KTEB FCSTER COMMENTS: CHC OF RA PREVAILING AT TIMES THIS AFTN. SNOW
ACCUMULATION ON RUNWAY OF AROUND AN INCH.
KHPN FCSTER COMMENTS: CHC OF RA PREVAILING AT TIMES THIS AFTN. SNOW
ACCUMULATION ON RUNWAY OF AROUND AN INCH.
KISP FCSTER COMMENTS: CHC THAT RA COULD PREVAIL THROUGH THE ENTIRE
DAY WITH JUST PERHAPS A BRIEF PERIOD OF -RASN AT THE ONSET OF PCPN.
SNOW ACCUMULATION ON RUNWAY OF BELOW AN INCH.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...VFR. NW FLOW G15-20KT.
.THU...VFR. WNW FLOW G15-20KT.
.FRI...VFR.
.SAT...MAINLY VFR...PSBL MVFR.
&&
.MARINE...
N-NW WINDS IN THE WAKE OF LOW PRESSURE PASSING SE OF LONG ISLAND
SHOULD REACH SCA CRITERIA THIS EVENING ACROSS THE OCEAN WATERS AND
THE ERN SOUND/BAYS...AND AN SCA WILL BE ISSUED FOR TONIGHT.
SCA CONDS MAY CONTINUE INTO THE MORNING ON THE ERN OCEAN
WATERS...BUT THERE SHOULD BE A RELATIVE LULL IN THE AFTERNOON
BEFORE STRONGER WINDS REDEVELOP BETWEEN THE DEPARTING LOW AND
BUILDING HIGH PRESSURE. SCA CONDS EXPECTED AGAIN WED NIGHT AND
POSSIBLY INTO THU MORNING...ESPECIALLY ON THE OCEAN WATERS MAINLY
DUE TO LINGERING SEAS. SUB-ADVY CONDS MAINLY EXPECTED
THEREAFTER...EXCEPT PERHAPS BRIEFLY BEHIND A WEAK COLD FRONT THU
NIGHT...AND FOR SEAS ON THE EASTERN OCEAN WATERS LATE SAT NIGHT
DUE TO A PERSISTENT SW FLOW.
&&
.HYDROLOGY...
LOW PRESSURE AFFECTING THE REGION THROUGH TONIGHT SHOULD BRING 1/4
TO 1/2 INCH LIQUID EQUIVALENT QPF...WITH THE HIGHEST AMOUNTS
ALONG THE COAST.
&&
.EQUIPMENT...
KOKX WSR-88D IS OUT OF SERVICE DUE TO A MAJOR NON STORM RELATED
MECHANICAL FAILURE. OSF RADAR OPERATIONS CENTER TECHS HAVE
ARRIVED TO BEGIN WORK...AND THE RADAR IS EXPECTED TO RETURN TO
SERVICE BY THE FIRST WEEK OF DECEMBER.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ330-340-350-353-355.
&&
$$
SYNOPSIS...GOODMAN/24
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...24
AVIATION...JC
MARINE...GOODMAN/24
HYDROLOGY...GOODMAN
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
140 AM EST TUE NOV 27 2012
.UPDATE...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD AND PROGRESSIVE
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. MAIN PATTERN CONSISTS
OF RIDGING OVER THE PACIFIC COAST/INTER-MOUNTAIN WEST FOLLOWED
DOWNSTREAM BY GENERAL TROUGHING TO THE EAST OF THE CONTINENTAL
DIVIDE. IN THE SHORT TERM...MAIN FEATURES OF INTEREST FOR OUR
FORECAST ARE SHORTWAVE ENERGY ROUNDING THE BASE OF THE MAIN LONGWAVE
TROUGH ALONG THE NORTHERN GULF COAST...AND UPPER LEVEL JET ENERGY
EXTENDING DOWN THE SPINE OF THE APPALACHIANS.
AT THE SURFACE...A WEAK COLD FRONT ASSOCIATED WITH THE PASSING UPPER
LEVEL ENERGY WILL BE APPROACHING FROM THE NORTHWEST THROUGH THE LATE
AFTERNOON/EVENING HOURS AS THE CURRENT RIDGE OF HIGH PRESSURE OVER
THE REGION RETREATS SOUTH AND EAST INTO THE ATLANTIC.
LARGE SCALE SYNOPTIC FORCING AHEAD OF THE ABOVE MENTIONED SHORTWAVE
COUPLED WITH FAVORABLE RRQ JET DYNAMICS HAVE BEEN SUPPORTING A BAND
OF RAIN TO THE NORTHWEST OF THE FORECAST AREA EXTENDING FROM THE MS
DELTA TO THE FL PANHANDLE AND SOUTH/CENTRAL GA.
&&
.SHORT TERM (TONIGHT THROUGH THURSDAY)...
THIS EVENING/TONIGHT...BAND OF RAIN TO OUR NORTHWEST WILL CONTINUE
MAKING SOME PROGRESS EASTWARD INTO THE EVENING HOURS...HOWEVER THERE
IS GOOD NWP AGREEMENT IN AN OVERALL WEAKENING AND EVENTUAL
DISSIPATION BEFORE ANY SIGNIFICANT IMPACT CAN ARRIVE IN OUR NORTHERN
ZONES. THIS SCENARIO MAKES SENSE WITH THE BEST DEEP LAYER MOISTURE
PASSING TO OUR NORTH AND THE SLOW NORTHEASTWARD RETREAT OF THE
INITIAL JET DYNAMICS.
GFS/ECMWF BOTH SHOW AT LEAST SOME DEEP LAYER QG FORCING PASSING OVER
THE NORTHERN HALF OF THE FORECAST AREA TONIGHT WITH THE ACTUAL
SHORTWAVE PASSAGE. WITH THIS IN MIND...ALONG WITH WEAK LOW LEVEL
FRONTAL FOCUS...CAN NOT RULE OUT A FEW SHOWERS TO THE NORTH OF TAMPA
BAY OVERNIGHT...AND ESPECIALLY UP TOWARD LEVY COUNTY. DOUBTFUL THAT
MANY LOCATIONS WILL SEE ANY MEASURABLE PRECIP...BUT HIRES CONVECTION
ALLOWING GUIDANCE SUITE DOES SUGGEST AT LEAST A FEW SURVIVING
SHOWERS. THERMAL RIDGE AHEAD OF THE FRONT WILL HELP KEEP
TEMPERATURES UP FOR A WHILE TONIGHT BEFORE SOME CAA BEGINS TO FILTER
IN LATE. EARLY MORNING LOW TEMPS WILL GENERALLY RUN IN THE MIDDLE
50S TO AROUND 60. FAR NORTHERN AREAS MAY BRIEFLY DIP DOWN TOWARD 50.
HAVE KEPT PATCHY FOG IN THE GRIDS. FOG POTENTIAL WILL DEPEND ON
EXACT FRONTAL TIMING LATE TONIGHT...AND WILL LET THE NEXT SHIFT
RE-EVALUATE THE POTENTIAL FOR ANY SIGNIFICANT VIS RESTRICTIONS.
WEDNESDAY...UPPER LEVEL ENERGY QUICKLY TRANSLATES EASTWARD EARLY
WEDNESDAY ALLOWING THE PATTERN TO FLATTEN OVER THE PENINSULA.
SIGNIFICANT DRYING OF THE DEEP LAYER COLUMN WILL THEN ADVECT
SOUTHWARD ACROSS THE AREA DURING THE DAY. LOOK FOR DECREASING CLOUDS
FROM NORTH TO SOUTH FAIRLY QUICKLY. GOOD DIURNAL MIXING AND NO LACK
OF SOLAR INSOLATION WILL ALLOW TEMPS TO REACH THE LOWER TO MID 70S
NORTH OF I-4...AND MID 70S TO AROUND 80 SOUTH OF TAMPA BAY.
WEDNESDAY NIGHT THROUGH THURSDAY...SEASONABLE AND GENERALLY DRY
CONDITIONS EXPECTED. STRONG HIGH PRESSURE TO OUR NORTH WILL PROVIDE
A BREEZY EASTERLY FLOW ACROSS THE PENINSULA. LITTLE TO NO SYNOPTIC
FORCING WILL PREVENT ANY ORGANIZED SHOWER ACTIVITY. ONSHORE FLOW AND
SOME LOW LEVEL MOISTURE SHOULD RESULT IN SPEED CONVERGENCE FOCUS
SHOWERS ALONG THE EAST COAST FROM TIME TO TIME. BEST CHANCES ARE FOR
ANY OF THESE WEAK SHOWERS TO DISSIPATE BEFORE REACHING OUR ZONES AND
WILL KEEP RAIN CHANCES AT OR BELOW 10% THROUGH THE DURATION OF THE
PERIOD.
&&
.LONG TERM (FRIDAY - MONDAY)...
A WEAK UPPER LEVEL RIDGE ACROSS THE AREA SLIDES EAST AS NEARLY
ZONAL FLOW MOVES INTO THE REGION...FOLLOWED BY A SLIGHTLY STRONGER
UPPER RIDGE FOR SUN/MON. THIS PATTERN WILL PROVIDE A WARM DRY AND
STABLE ATMOSPHERE. SURFACE HIGH PRESSURE HANGING OVER/OFF THE
EASTERN SEABOARD...AND GETTING REINFORCED FROM THE NORTH EARLY IN
THE WEEKEND...MAINTAINS A ROBUST AT TIMES ENE TO EAST FLOW WITH A
GRADUAL INCREASE IN LOW LEVEL MOISTURE. THERE IS ENOUGH OF A
MOISTURE INCREASE TO SUGGEST A STRAY SHOWER OR 2 BUT WILL KEEP POPS
AT 10 PERCENT OF LESS. TEMPERATURES WILL RUN ABOVE NORMAL BY UP TO
2-4 DEGREES.
&&
.AVIATION...
VFR CONDITIONS MUCH OF PERIOD WITH THE EXCEPTION OF 5SM BR 10-14Z IN
LAKELAND AND PUNTA GORDA. HIGH CLOUDS TO LIMIT FOG POTENTIAL TO
AREAS AWAY FROM COAST. PRECIP IN FLORIDA PAN HANDLE THIS AFTERNOON
TO MOVE NORTH OF AREA TONIGHT. ASSOCIATED COLD FRONT TO WEAKEN...
REMAIN DRY...AND MOVE SOUTH OF FORT MYERS BY 12Z.
&&
.MARINE...
A WEAK COLD FRONT WILL PASS THROUGH THE EASTERN GULF OF MEXICO
TONIGHT THROUGH EARLY WEDNESDAY VEERING WINDS AROUND TO THE NORTH
AND NORTHEAST WITH TIME. A STRONG AREA OF HIGH PRESSURE WILL BUILD
TO THE NORTH OF THE REGION IN THE WAKE OF THIS FRONT ON WEDNESDAY
AND THEN SLIDE EAST TO THE MID-ATLANTIC COAST BY THE END OF THE
WEEK. ELEVATED EASTERLY FLOW IS ANTICIPATED TO DEVELOP AROUND THIS
HIGH FOR THE SECOND HALF OF THE WEEK. EASTERLY WINDS ARE LIKELY TO
REACH CAUTIONARY LEVELS AT TIMES THROUGH AT LEAST THE FIRST HALF OF
THE UPCOMING WEEKEND.
&&
.FIRE WEATHER...
A WEAK COLD FRONT WILL PASS THROUGH THE REGION TONIGHT AND EARLY
WEDNESDAY WITH ONLY A SLIGHT CHANCE OF A LIGHT SHOWER OR SPRINKLE.
DRIER AIR WILL BRIEFLY ATTEMPT TO FILTER IN FROM THE NORTH ON
WEDNESDAY BEFORE WINDS VEER TO THE EAST AND TRANSPORT INCREASING
ATLANTIC MOISTURE BACK INTO THE REGION. NO SIGNIFICANT FIRE WEATHER
CONCERNS ARE ANTICIPATED THROUGH AT LEAST THE FIRST HALF OF THE
UPCOMING WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 58 77 56 76 / 0 0 0 10
FMY 61 80 60 81 / 10 0 10 10
GIF 55 79 54 77 / 10 0 10 10
SRQ 60 77 57 77 / 0 0 0 0
BKV 51 77 50 77 / 10 0 0 10
SPG 62 75 59 75 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...NOAH
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1100 AM EST TUE NOV 27 2012
.UPDATE...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD AND PROGRESSIVE
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. MAIN PATTERN CONSISTS
OF RIDGING OVER TH PACIFIC COAST/INTER-MOUNTAIN WEST FOLLOWED
DOWNSTREAM BY GENERAL TROUGHING TO THE EAST OF THE CONTINENTAL
DIVIDE. IN THE SHORT TERM...MAIN FEATURES OF INTEREST FOR OUR
FORECAST ARE SHORTWAVE ENERGY ROUNDING THE BASE OF THE MAIN LONGWAVE
TROUGH ALONG THE NORTHERN GULF COAST...AND UPPER LEVEL JET ENERGY
EXTENDING DOWN THE SPINE OF THE APPALACHIANS.
AT THE SURFACE...A WEAK COLD FRONT ASSOCIATED WITH THE PASSING UPPER
LEVEL ENERGY WILL BE APPROACHING FROM THE NORTHWEST THROUGH THE
AFTERNOON/EVENING HOURS AS THE CURRENT RIDGE OF HIGH PRESSURE OVER
THE REGION RETREATS SOUTH AND EAST INTO THE ATLANTIC.
LARGE SCALE SYNOPTIC FORCING AHEAD OF THE ABOVE MENTIONED SHORTWAVE
COUPLED WITH FAVORABLE RRQ JET DYNAMICS HAVE BEEN SUPPORTING A BAND
OF RAIN TO THE NORTHWEST OF THE FORECAST AREA EXTENDING FROM THE MS
DELTA TO THE FL PANHANDLE AND SOUTH/CENTRAL GA. THIS BAND OF RAIN
WILL BE MAKING SOME PROGRESS EASTWARD THE REST OF TODAY...HOWEVER
THERE IS GOOD NWP AGREEMENT IN AN OVERALL WEAKENING AND EVENTUAL
DISSIPATION BEFORE ANY SIGNIFICANT IMPACT CAN ARRIVE IN OUR NORTHERN
ZONES. THIS SCENARIO MAKES SENSE WITH THE BEST DEEP LAYER MOISTURE
PASSING TO OUR NORTH AND THE SLOW NORTHEASTWARD RETREAT OF THE
INITIAL JET DYNAMICS.
GFS/ECMWF BOTH SHOW AT LEAST SOME DEEP LAYER QG FORCING PASSING OVER
THE NORTHERN HALF OF THE FORECAST AREA TONIGHT WITH THE ACTUAL
SHORTWAVE PASSAGE. WITH THIS IN MIND...ALONG WITH THE FRONTAL
FOCUS...CAN NOT RULE OUT A FEW SHOWERS TO THE NORTH OF TAMPA BAY
OVERNIGHT...AND ESPECIALLY UP TOWARD LEVY COUNTY. DOUBTFUL THAT MANY
LOCATIONS WILL SEE ANY MEASURABLE PRECIP...BUT HIRES CONVECTION
ALLOWING GUIDANCE SUITE DOES SUGGEST AT LEAST A FEW SURVIVING
SHOWERS.
UPPER LEVEL ENERGY QUICKLY TRANSLATES EASTWARD EARLY WEDNESDAY
ALLOWING THE PATTERN TO FLATTEN OVER THE PENINSULA. SIGNIFICANT
DRYING OF THE DEEP LAYER COLUMN WILL THEN ADVECT SOUTHWARD ACROSS
THE AREA DURING THE DAY.
&&
.AVIATION...
VFR CONDITIONS MUCH OF PERIOD. MVFR VISIBILITY POSSIBLE AFTER 06Z
BUT LEFT OPTIMISTIC FOR NOW. WILL MAKE FINAL DETERMINATION IN 18Z
FORECAST.
&&
.MARINE...
A WEAK COLD FRONT WILL PASS THROUGH THE EASTERN GULF OF MEXICO
TONIGHT THROUGH EARLY WEDNESDAY VEERING WINDS AROUND TO THE NORTH
AND NORTHEAST WITH TIME. A STRONG AREA OF HIGH PRESSURE WILL BUILD
TO THE NORTH OF THE REGION IN THE WAKE OF THIS FRONT ON WEDNESDAY
AND THEN SLIDE EAST TO THE MID-ATLANTIC COAST BY THE END OF THE
WEEK. ELEVATED EASTERLY FLOW IS ANTICIPATED TO DEVELOP AROUND THIS
HIGH FOR THE SECOND HALF OF THE WEEK. EASTERLY WINDS ARE LIKELY TO
REACH CAUTIONARY LEVELS AT TIMES THROUGH AT LEAST THE FIRST HALF OF
THE UPCOMING WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 77 60 78 58 / 10 10 0 10
FMY 80 62 80 59 / 10 10 10 10
GIF 79 59 78 56 / 10 10 0 10
SRQ 77 61 79 57 / 10 10 0 10
BKV 78 51 77 49 / 10 10 0 0
SPG 76 63 76 61 / 10 10 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...NOAH
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
303 AM EST TUE NOV 27 2012
.SHORT TERM /TODAY THROUGH THURSDAY/...
HIGH PRESSURE WHICH HAS PROVIDED FAIR WEATHER ACROSS THE REGION OVER
THE LAST FEW DAYS WILL MOVE EAST THIS MORNING...ALLOWING MOISTURE
AHEAD OF AN APPROACHING COLD FRONT TO WORK ITS WAY INTO WESTERN AND
NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. CURRENT RADAR
IMAGERY WEST OF THE REGION DOES NOT INDICATE MUCH IN THE WAY OF
PRECIPITATION...BUT THIS COVERAGE IS EXPECTED TO INCREASE AS AN
UPPER TROUGH PIVOTS INTO THE SOUTHEAST AND STRENGTHENS THE SYSTEM TO
THE NORTHWEST. AS MUCH OF THE ENERGY AHEAD OF THE FRONT SHIFTS TO
THE NORTHEAST WITH THE SURFACE LOW...NOT EXPECTING MUCH
PRECIPITATION COVERAGE INTO NORTHEAST FLORIDA. THE BEST CHANCE FOR
RAINFALL ACROSS THE CWA WILL BE IN SOUTHEAST GEORGIA FROM NOON TO
MIDNIGHT TODAY.
THE SURFACE FRONT WILL CLEAR TO THE SOUTH OVERNIGHT TONIGHT...WITH
HIGH PRESSURE BUILDING IN BEHIND. THIS HIGH WILL BE JUST NORTH OF
THE REGION WEDNESDAY AND...THEN SHIFT OFF THE EAST COAST THURSDAY.
THIS WILL SET UP AN ONSHORE FLOW THURSDAY AFTERNOON...BUT BEST
MOISTURE FOR RAINFALL SHOULD STAY OFFSHORE INITIALLY.
HAVE FAVORED GFS MOS NUMBERS THIS PERIOD. READINGS NEAR
CLIMATOLOGICAL NORMS ARE EXPECTED DESPITE THE PASSING OF THE COLD
FRONT...AS THE AIRMASS BEHIND IT IS NOT THAT COLD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WITH SURFACE HIGH PRESSURE REMAINING OVER THE CAROLINAS ONSHORE FLOW
WILL CONTINUE THURSDAY NIGHT THROUGH SUNDAY. WHILE MAINLY COASTAL
SHOWERS ARE EXPECTED...THERE COULD BE A FEW PERIODS WHERE STRONGER
RIBBONS OF MOISTURE COULD PUSH RAIN FURTHER INLAND. THE SURFACE HIGH
IS PROGGED TO SLIP A LITTLE TO THE SOUTH ON MONDAY...WHICH WOULD
PUSH THE COASTAL SHOWERS SOUTH OF THE FORECAST AREA. HAVE FAVORED
GFS MOS GUIDANCE THIS PERIOD...WITH ABOVE NORMAL TEMPERATURES
EXPECTED.
&&
.AVIATION...TEMPO MVFR POSSIBLE AT JAX...CRG...VQQ AND GNV EARLY
THIS MORNING WITHIN A COUPLE HOURS OF SUNRISE. THE ONLINE RAP MODELS
AND SHORT TERM GUIDANCE SUGGEST THAT LOWERING CIGS MAY ROTATE NNE
FROM CENTRAL FL EARLY THIS MORNING...WITH THE RAP AS LOW AS LIFR
CONDITIONS. DID NOT NOT ANY OF THESE LOWER CIGS TO OUR SOUTH EARLY
THIS MORNING...BUT DID INCLUDE TEMPO 2.5-3 KFT AT GNV AND DUVAL
COUNTY TERMINALS. HIGH AND MID CLOUDS WILL BLANKET THE AREA TODAY IN
ADVANCE OF THE FRONT...AND INCLUDED VCSH AT SSI THIS EVENING.
&&
.MARINE...SEPARATED THE COASTAL WATERS FORECAST BETWEEN NEAR AND
OFFSHORE. WINDS AND SEAS WILL BUILD OVER THE OFFSHORE WATERS LATE
TONIGHT INTO WED FOLLOWING THE FRONTAL PASSAGE...WITH SCEC
CONDITIONS POSSIBLE OVER THE OFFSHORE WATERS. WINDS WILL GRADUALLY
RELAX INTO THE WEEKEND AS HIGH PRESSURE BUILD NNE OF THE REGION.
PERSISTENT ONSHORE FLOW IS EXPECTED WITH AN INCREASE IN EASTERLY
SWELLS.
RIP CURRENTS: LOW RISK TODAY DUE TO OFFSHORE FLOW FLOW AND LOWER
WAVE HEIGHTS. MODERATE RISK EXPECTED ON WEDNESDAY DUE TO INCREASING
NNE FLOW. THE RIP CURRENT RISK IS EXPECTED TO REMAIN ELEVATED
THROUGH THE WEEKEND DUE TO PERSISTENT ONSHORE FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 64 43 68 41 / 60 50 10 0
SSI 67 51 65 51 / 30 30 10 10
JAX 70 50 67 49 / 20 20 10 10
SGJ 72 53 69 53 / 10 20 10 10
GNV 73 47 72 45 / 10 20 10 0
OCF 76 50 74 48 / 10 20 10 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
STRUBLE/ENYEDI
AREA FORECAST DISCUSSION
NWS JACKSON KY
1222 PM EST TUE NOV 27 2012
.UPDATE...
ISSUED AT 1222 PM EST TUE NOV 27 2012
EVEN AFTER UPDATING ONCE FOR A SLOWER CLEARING TREND...IT WAS STILL
NOT ENOUGH. HAVE SLOWED THE CLEARING TREND EVEN MORE. THE NAM HAS
MISERABLY FAILED IN ITS FORECAST FOR LOW LEVEL MOISTURE...WITH THE
HIGHER LOW LEVEL MOISTURE LINGERING LONGER IN THE GFS CERTAINLY
VERIFYING BETTER TODAY.
UPDATE ISSUED AT 1017 AM EST TUE NOV 27 2012
CLOUDS LOOK LIKE THEY WILL BE SLOWER TO CLEAR THAN WAS FORECAST. THE
GFS IS HOLDING ONTO THEM LONGER THAN THE NAM...AND PREFER A FORECAST
WEIGHTED TOWARD THE GFS.
UPDATE ISSUED AT 630 AM EST TUE NOV 27 2012
LAST OF THE MEASURABLE PRECIPITATION IS NOW EXITING OFF TO THE EAST.
HOWEVER...NAM BUFR SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
MOISTURE DEPTH. GIVEN THE REPORTS OF MIST AT THE ASOS SITES THIS
MORNING...OPTING TO KEEP A MENTION OF DRIZZLE IN THE FORECAST THROUGH
THE MORNING FOR THE SOUTHEAST TWO THIRDS OF THE AREA. IT LOOKS LIKE
THE SNOW MAY HAVE BEEN AVOIDED EVEN AT THE HIGHER ELEVATION
LOCATIONS. THUS...HAVE UPDATED TO REMOVE ANY FURTHER MENTION OF SNOW.
FINALLY...JUST TWEAKED THE TEMPERATURE CURVES A BIT THROUGH THE
MORNING TO REFLECT A BETTER LOW END TEMP. ALSO KEPT TEMPERATURES
BOTTOMED OUT THROUGH THE MORNING WITH ONGOING CLOUD COVER/DRIZZLE.
FORTUNATELY...TEMPERATURES ARE ABOVE FREEZING...SO NO REAL THREAT FOR
SLIPPERY CONDITIONS DEVELOPING WITH THE DRIZZLE. FORECAST UPDATE HAS
ALREADY BEEN SENT TO NDFD AND A NEW ZFP HAS BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIR MASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1222 PM EST TUE NOV 27 2012
LOW CLOUDS WITH LARGELY IFR CEILINGS LINGERED ACROSS THE AREA EARLY
THIS AFTERNOON. CEILINGS WILL EVENTUALLY RISE AND THEN BREAK UP FROM
NW TO SE...WITH VFR RETURNING FROM NW TO SE BETWEEN ABOUT 21Z AND
03Z. HOWEVER...CONFIDENCE IN THE TIMING FOR THIS IS WEAK.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1018 AM EST TUE NOV 27 2012
.UPDATE...
ISSUED AT 1017 AM EST TUE NOV 27 2012
CLOUDS LOOK LIKE THEY WILL BE SLOWER TO CLEAR THAN WAS FORECAST. THE
GFS IS HOLDING ONTO THEM LONGER THAN THE NAM...AND PREFER A FORECAST
WEIGHTED TOWARD THE GFS.
UPDATE ISSUED AT 630 AM EST TUE NOV 27 2012
LAST OF THE MEASURABLE PRECIPITATION IS NOW EXITING OFF TO THE EAST.
HOWEVER...NAM BUFR SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
MOISTURE DEPTH. GIVEN THE REPORTS OF MIST AT THE ASOS SITES THIS
MORNING...OPTING TO KEEP A MENTION OF DRIZZLE IN THE FORECAST THROUGH
THE MORNING FOR THE SOUTHEAST TWO THIRDS OF THE AREA. IT LOOKS LIKE
THE SNOW MAY HAVE BEEN AVOIDED EVEN AT THE HIGHER ELEVATION
LOCATIONS. THUS...HAVE UPDATED TO REMOVE ANY FURTHER MENTION OF SNOW.
FINALLY...JUST TWEAKED THE TEMPERATURE CURVES A BIT THROUGH THE
MORNING TO REFLECT A BETTER LOW END TEMP. ALSO KEPT TEMPERATURES
BOTTOMED OUT THROUGH THE MORNING WITH ONGOING CLOUD COVER/DRIZZLE.
FORTUNATELY...TEMPERATURES ARE ABOVE FREEZING...SO NO REAL THREAT FOR
SLIPPERY CONDITIONS DEVELOPING WITH THE DRIZZLE. FORECAST UPDATE HAS
ALREADY BEEN SENT TO NDFD AND A NEW ZFP HAS BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIR MASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM EST TUE NOV 27 2012
COLD FRONT WILL MARCH SOUTHWARD ACROSS EASTERN KENTUCKY THIS MORNING.
CIGS WILL REMAIN BELOW AIRPORT MINIMUMS THROUGH MUCH OF THE MORNING.
CIGS WILL IMPROVE BACK TO VFR AND CLEAR BY EARLY TO MID
AFTERNOON. THE VFR CONDITIONS WILL LINGER THROUGH TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
630 AM EST TUE NOV 27 2012
.UPDATE...
ISSUED AT 630 AM EST TUE NOV 27 2012
LAST OF THE MEASURABLE PRECIPITATION IS NOW EXITING OFF TO THE EAST.
HOWEVER...NAM BUFR SOUNDINGS CONTINUE TO SHOW A DECENT LOW LEVEL
MOISTURE DEPTH. GIVEN THE REPORTS OF MIST AT THE ASOS SITES THIS
MORNING...OPTING TO KEEP A MENTION OF DRIZZLE IN THE FORECAST THROUGH
THE MORNING FOR THE SOUTHEAST TWO THIRDS OF THE AREA. IT LOOKS LIKE
THE SNOW MAY HAVE BEEN AVOIDED EVEN AT THE HIGHER ELEVATION
LOCATIONS. THUS...HAVE UPDATED TO REMOVE ANY FURTHER MENTION OF SNOW.
FINALLY...JUST TWEAKED THE TEMPERATURE CURVES A BIT THROUGH THE
MORNING TO REFLECT A BETTER LOW END TEMP. ALSO KEPT TEMPERATURES
BOTTOMED OUT THROUGH THE MORNING WITH ONGOING CLOUD COVER/DRIZZLE.
FORTUNATELY...TEMPERATURES ARE ABOVE FREEZING...SO NO REAL THREAT FOR
SLIPPERY CONDITIONS DEVELOPING WITH THE DRIZZLE. FORECAST UPDATE HAS
ALREADY BEEN SENT TO NDFD AND A NEW ZFP HAS BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIRMASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM EST TUE NOV 27 2012
COLD FRONT WILL MARCH SOUTHWARD ACROSS EASTERN KENTUCKY THIS MORNING.
CIGS WILL REMAIN BELOW AIRPORT MINIMUMS THROUGH MUCH OF THE MORNING.
CIGS WILL IMPROVE BACK TO VFR AND CLEAR BY EARLY TO MID
AFTERNOON. THE VFR CONDITIONS WILL LINGER THROUGH TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
245 AM EST TUE NOV 27 2012
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
COLD FRONT CONTINUES TO MARCH SOUTHWARD ACROSS NORTHERN AND CENTRAL
KENTUCKY THIS MORNING. PRECIPITATION IS ALREADY STARTING TO END FROM
WEST TO EAST AND WILL CONTINUE TO END THROUGH DAYBREAK...HOLDING ON
ACROSS THE FAR EAST AND SOUTHEAST UNTIL ABOUT 13Z. HRRR SEEMS IN
PRETTY GOOD AGREEMENT WITH CURRENT PRECIPITATION TRENDS AND HAS A
VERY GOOD HANDLE ON ENDING OF PRECIPITATION THIS MORNING. AS IT
STANDS NOW...IT APPEARS PRECIPITATION SHOULD PULL OUT OF THE AREA
PRIOR TO A CHANGEOVER TO SNOW. THE ONLY EXCEPTION TO THIS MAY BE NEAR
THE VIRGINIA BORDER AND ONLY IN ELEVATIONS ABOVE 2000 FEET.
REGARDLESS...WITH ONLY LIGHT PRECIPITATION TOTALS ANTICIPATED AND
WARM SURFACE TEMPERATURES (ABOVE FREEZING)...NOT ANTICIPATING ANY
SNOWFALL ACCUMULATIONS. WE HAVE SEEN A CHANGEOVER TO SNOW AT
CVG...BUT THIS CHANGEOVER TO THE SOUTH WILL NOT PROGRESS FAST
ENOUGH. TEMPERATURES WILL STILL COOL INTO THE LOWER 30S IN THE NORTH
PRIOR TO DAYBREAK...SO STILL GOING TO BE PLENTY COOL. GIVEN THE COLD
ADVECTION TODAY...AND POSSIBLE LINGERING CLOUD COVER...HAVE WENT
BELOW GUIDANCE FOR HIGHS TODAY...GENERALLY AROUND 40 FOR MOST AREAS.
SKIES WILL CLEAR THIS AFTERNOON AND EVENING...WITH A COLD NIGHT
EXPECTED TONIGHT. A FAST MOVING WAVE IS EXPECTED TO PUSH ACROSS THE
NORTHERN OHIO RIVER VALLEY...BUT CLOUD COVER FROM THIS SYSTEM WILL
REMAIN NORTH OF KENTUCKY. THUS...WE SHOULD DECOUPLE NICELY TONIGHT IN
THE VALLEYS WITH TEMPERATURES FALLING WELL INTO THE 20S. CONTINUED TO
GO BELOW GUIDANCE FOR HIGHS ON WEDNESDAY GIVEN VERY LITTLE
IMPROVEMENT IN THE COOL AIRMASS OVER THE AREA. MODELS MAY BE TOO
AGGRESSIVE ON BRINGING THE WARMER WEATHER BACK INTO EASTERN KENTUCKY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 245 AM EST TUE NOV 27 2012
SURFACE HIGH PRESSURE OVER EASTERN KY AND A 50 H TROF OVER NEW
ENGLAND WITH RIDGING BUILDING INTO THE MIDWEST WILL BEGIN THE
EXTENDED FORECAST WITH COOL BUT FAIR WEATHER. HIGH TEMPS WILL SLOWLY
CLIMB INTO THE LOWER 50S AFTER A COLD NIGHT GENERALLY IN THE UPPER
20S. BY THURSDAY NIGHT THE SURFACE HIGH WILL BE LOCATED OFF THE
CAROLINA COAST WITH SOUTHERLY WINDS AND TEMPERATURES ONLY FALLING
INTO THE LOWER 30S. THEN ON FRIDAY A 50H DISTURBANCE WILL SWEEP THRU
THE OHIO VALLEY AND BRING A LOW CHANCE FOR RAIN TO EASTERN KY.
RAINFALL SHOULD BE LIGHT AND WITH CONTINUED SOUTHERLY WINDS AT THE
SFC TEMPERATURES RISE INTO THE MID AND UPPER 50S. CLOUDS AND A FEW
VERY LIGHT SHOWERS WILL LINGER INTO SAT WITH TEMPS ONLY FALLING INTO
THE LOWER 40S SAT MORNING BEFORE CLIMBING INTO THE UPPER 50S. ANOTHER
FAST MOVING SHORT WAVE WILL SWEEP THRU THE OHIO VALLEY ON SUN WITH
EARLY MORNING TEMPS IN THE UPPER 40S AND DAYTIME HIGHS IN THE LOWER
60S. THE RAIN MAY LINGER THRU SUN NIGHT BUT THE UPPER WEATHER PATTERN
WILL BEGIN TO SHIFT FROM A FAST ZONAL FLOW TO A MORE AMPLIFIED
PATTERN WITH 50H RIDGING BUILDING INTO THE MISS RIVER VALLEY. THAT
KEEPS NORTHWEST FLOW OVER THE AREA FOR SUNDAY NIGHT WITH CONTINUES
LIGHT RAIN POSSIBLE AS TEMPERATURES MONDAY MORNING ONLY FALL INTO THE
UPPER 40S WITH CONTINUED SW FLOW. LOOK FOR SOME CLEARING ON MONDAY AS
THE 50H RIDGE BUILDS INTO THE OHIO VALLEY AND TEMPERATURES SOAR INTO
THE MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1229 AM EST TUE NOV 27 2012
COLD FRONT WILL MARCH SOUTHWARD ACROSS EASTERN KENTUCKY OVERNIGHT
INTO TUESDAY MORNING. CIGS WILL QUICKLY COME DOWN OVER THE NEXT 2 TO
3 HOURS WITH CIGS SOLIDLY AROUND 800 FEET OR LOWER BY 09Z. WITH SOME
HEAVIER PRECIPITATION...A SLIGHT REDUCTION IN VISIBILITY CAN BE
EXPECTED THROUGH ABOUT DAYBREAK. THE THREAT FOR SNOW WILL REMAIN AT
OR ABOVE 2000 FEET ON THE RIDGES NEAR THE VIRGINIA BORDER.
HOWEVER...VERY LITTLE IF ANY ACCUMULATION IS EXPECTED. THE CIGS WILL
IMPROVE AND CLEAR BY EARLY TO MID AFTERNOON...ALTHOUGH MUCH OF THE
MORNING WILL REMAIN WITH LOW CIGS. THE VFR CONDITIONS WILL LINGER
THROUGH TUESDAY NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
345 PM EST TUE NOV 27 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY.
TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND
WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
BLEND OF RECENT SURFACE AND SATELLITE DATA SHOWS COLD POOL
STRATOCUMULUS CLOUD BANK EXTENDS AS FAR WEST AS WESTERN OHIO. RECENT
RAP AND NAM MODEL OUTPUT SHOW THIS COLD POOL CAPPED BY A SUBSIDENCE
TEMPERATURE INVERSION...TRAPPING THE CONDENSED MOISTURE. SO IT
APPEARS MORE LIKELY THAT CLOUDS CAN LINGER INTO TONIGHT ACROSS MUCH
OF THE UPPER OHIO VALLEY.
THE NAM MODEL OUTPUT SHOWS THE SUBSIDENCE CONTINUING DAYTIME
WEDNESDAY...DUE TO EASTBOUND MIDWEST HIGH PRESSURE...WHICH WILL
EVENTUALLY CAUSE CLEARING LATER TONIGHT...SO THAT MOST PARTS OF THE
UPPER OHIO VALLEY SHOULD BE MOSTLY SUNNY DAYTIME WEDNESDAY.
SOME SREF MODEL MEMBERS DO SHOW A SECONDARY COLD FRONT PASSING
EASTWARD THROUGH THE GREAT LAKES DURING WEDNESDAY...WHICH MAY CAUSE
SOME CLOUDS AND PERHAPS ISOLATED SNOW SHOWERS LATE ACROSS THE I-80
CORRIDOR OF NORTHWEST PENNSYLVANIA.
FORECASTED TEMPERATURES TO BE ABOUT 5 DEGREES COLDER THAN NORMAL
THIS PERIOD BASED ON CONSENSUS OF RECENT NAM AND GFS MOS AND SREF
MEAN VALUES.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
H8 FLOW IS EXPECTED TO BECOME ANTICYCLONIC WEDNESDAY EVENING...
LIMITING ANY LAKE EFFECT POTENTIAL TO JUST AN ISOLATED SNOW SHOWER
OR TWO ACROSS THE NORTH. HIGH PRESSURE THEN BUILDS IN THROUGH
THURSDAY NIGHT. A WEAK COLD FRONT DROPS INTO SRN NY/NRN PA
FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION
IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD
AS WELL.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
RECENT SURFACE AND SATELLITE DATA SHOWS THE MVFR COLD POOL
STRATOCUMULUS CLOUD BANK EXTENDING AS FAR WEST AS WESTERN OHIO.
RECENT RAP AND NAM MODEL OUTPUT SHOW A SUBSIDENCE-RELATED
TEMPERATURE INVERSION TRAPPING THIS CONDENSED MOISTURE. SO IT
APPEARS MORE LIKELY THAT THAT MVFR CEILINGS WILL PERSIST INTO EARLY
TONIGHT. HENCE HAVE DELAYED CLEARING TO VFR FOR MOST TAF SITES UNTIL
06Z.
NAM MODEL OUTPUT SHOWS FURTHER SUBSIDENCE ASSOCIATED WITH INCOMING
HIGH PRESSURE WILL PROMOTE VFR DAYTIME WEDNESDAY.
SURFACE WINDS WILL BE FROM THE NORTH AND NORTHWEST AT NO MORE THAN
8 KTS UNTIL 00Z...THEN EXPECT LIGHT WINDS TONIGHT. WINDS WEDNESDAY
WILL BE FROM THE WEST AT 12 KTS.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1219 PM EST TUE NOV 27 2012
.SYNOPSIS...
LIGHT SNOW WILL END WEST TO EAST ACROSS THE UPPER OHIO VALLEY BY
EARLY AFTERNOON...AS THE WEAK COLD FRONT EXITS EAST PAST THE
MOUNTAINS. HIGH PRESSURE WILL FOLLOW WITH DRY WEATHER INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND RADAR DATA...THE POSTFRONTAL LIGHT SNOW
CONTINUES TO EXIT WEST TO EAST ACROSS THE UPPER OHIO VALLEY THIS
MORNING. THE LIGHT ACCUMULATION OF SNOW HAS JUST ABOUT ENDED.
HENCE WILL ALLOW THE REMAINING WINTER WEATHER ADVISORIES TO EXPIRE
AT 1 PM.
RECENT RAP MODEL OUTPUT SHOWS HIGH PRESSURE SUBSIDENCE WILL THEN PROMOTE
DRY CONDITIONS THE REST OF THE AFTERNOON.
DUE TO LINGERING LIGHT SNOW AND THICKER CLOUDS...CONTINUE TO
EXPECT TEMPERATURES TO SHOW NO MORE THAN A 3 OR 4 DEGREE RISE FROM
CURRENT READINGS FOR AFTERNOON HIGH TEMPERATURES...BASED ON BLEND
OF RECENT GFS LAMP AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
COLDER AIR ALOFT WILL REMAIN OVER THE REGION THROUGH MUCH OF THE
SHORT TERM...AS A SFC HIGH SLOWLY MOVES FROM THE LOWER OHIO VALLEY
INTO THE MID ATLANTIC. WITH THE FLOW ALOFT IN A WEST-NORTHWEST
DIRECTION AND 85H TEMPS WELL BELOW 0C INTO EARLY THURSDAY...EXPECT
CLOUDS TO DEVELOP ON BOTH WED AND THU...WITH TEMPS REMAINING
BELOW NORMAL.
COLD POOL ALOFT FINALLY SHIFTS NORTHEASTWARD LATER THU AND THE LL
FLOW WILL VEER TO THE SOUTH. EXPECT A DECREASE IN CLOUD COVER BY
LATE THU...WITH JUST A BIT WARMER TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN
12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS
WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM
THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE
COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY
AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT
LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE
FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST.
HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE
FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL
TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
PER RECENT SURFACE AND RADAR DATA...THAT IS SHOWING THE
POSTFRONTAL BAND OF LIGHT SNOW AND CLOUDS CONTINUING TO SLOWLY
EXIT WEST TO EAST ACROSS THE UPPER OHIO VALLEY...HAVE CONTINUED TO
FORECAST A TREND TOWARD IMPROVING FLIGHT CONDITIONS THIS
AFTERNOON...WITH ALL TAF SITES VFR BY 22Z.
SUBSIDENCE ASSOCIATED WITH INCOMING HIGH PRESSURE WILL PROMOTE VFR
TONIGHT AND DAYTIME WEDNESDAY.
SURFACE WINDS WILL BE FROM THE NORTH AND NORTHWEST AT NO MORE THAN
8 KTS UNTIL 00Z...THEN EXPECT LIGHT WINDS TONIGHT. WINDS WEDNESDAY
WILL BE FROM THE WEST AT 12 KTS.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MDZ001.
OH...NONE.
PA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
WVZ041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1011 AM EST TUE NOV 27 2012
.SYNOPSIS...
LIGHT SNOW WILL END WEST TO EAST ACROSS THE UPPER OHIO VALLEY BY
EARLY AFTERNOON...AS THE WEAK COLD FRONT EXITS EAST PAST THE
MOUNTAINS. HIGH PRESSURE WILL FOLLOW WITH DRY WEATHER INTO THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND RADAR DATA...THE POSTFRONTAL LIGHT SNOW
HAS BEEN MORE SLOWLY EXITING WEST TO EAST ACROSS THE UPPER OHIO VALLEY
THIS MORNING. SO SOME LOCALES CAN STILL GET AN ADDITIONAL THIN
COATING OF LIGHT SNOW INTO MIDDAY. HENCE HAVE EXTENDED THE WINTER
WEATHER ADVISORY FOR THE WV-MD MOUNTAINS UNTIL 12PM-1PM.
RECENT RAP MODEL OUTPUT SHOWS HIGH PRESSURE SUBSIDENCE WILL THEN PROMOTE
DRY CONDITIONS THE REST OF THE AFTERNOON.
DUE TO LINGERING LIGHT SNOW AND THICKER CLOUDS...CONTINUE TO
EXPECT TEMPERATURES TO SHOW NO MORE THAN A 5 DEGREE RISE FROM
CURRENT READINGS FOR AFTERNOON HIGH TEMPERATURES...BASED ON BLEND
OF RECENT GFS LAMP AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
COLDER AIR ALOFT WILL REMAIN OVER THE REGION THROUGH MUCH OF THE
SHORT TERM...AS A SFC HIGH SLOWLY MOVES FROM THE LOWER OHIO VALLEY
INTO THE MID ATLANTIC. WITH THE FLOW ALOFT IN A WEST-NORTHWEST
DIRECTION AND 85H TEMPS WELL BELOW 0C INTO EARLY THURSDAY...EXPECT
CLOUDS TO DEVELOP ON BOTH WED AND THU...WITH TEMPS REMAINING
BELOW NORMAL.
COLD POOL ALOFT FINALLY SHIFTS NORTHEASTWARD LATER THU AND THE LL
FLOW WILL VEER TO THE SOUTH. EXPECT A DECREASE IN CLOUD COVER BY
LATE THU...WITH JUST A BIT WARMER TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN
12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS
WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM
THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE
COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY
AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT
LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE
FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST.
HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE
FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL
TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
PER RECENT SURFACE AND RADAR DATA THAT IS SHOWING A SLOWER EXIT
OF POSTFRONTAL LIGHT SNOW WEST TO EAST ACROSS THE UPPER OHIO
VALLEY...EXPECT SLOWER IMPROVEMENT FROM IFR TO VFR CONDITIONS LATE
THIS MORNING. HOWEVER STILL EXPECT MAINLY VFR AFTER 19Z DUE TO
SUBSIDENCE ASSOCIATED WITH INCOMING HIGH PRESSURE.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MDZ001.
OH...NONE.
PA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
WVZ041.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ023.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
846 AM EST TUE NOV 27 2012
.SYNOPSIS...
LIGHT SNOW WILL END WEST TO EAST ACROSS THE UPPER OHIO VALLEY BY
MIDDAY AS THE WEAK COLD FRONT EXITS EAST PAST THE MOUNTAINS. HIGH
PRESSURE WILL FOLLOW WITH DRY WEATHER INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND RADAR DATA...THE POSTFRONTAL LIGHT SNOW
WILL MORE SLOWLY EXIT WEST TO EAST ACROSS THE UPPER OHIO VALLEY
THIS MORNING. THIS MAY YIELD AN ADDED THIN COATING OF LIGHT SNOW
INTO MIDDAY. HOWEVER EXPECT HIGH PRESSURE SUBSIDENCE TO PROMOTE
DRY CONDITIONS THIS AFTERNOON.
LIKEWISE FORECASTED TEMPERATURES TO SHOW NO MORE THAN A 5 DEGREE
RISE FROM CURRENT READINGS FOR AFTERNOON HIGH TEMPERATURES...BASED
ON BLEND OF RECENT GFS LAMP AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
COLDER AIR ALOFT WILL REMAIN OVER THE REGION THROUGH MUCH OF THE
SHORT TERM...AS A SFC HIGH SLOWLY MOVES FROM THE LOWER OHIO VALLEY
INTO THE MID ATLANTIC. WITH THE FLOW ALOFT IN A WEST-NORTHWEST
DIRECTION AND 85H TEMPS WELL BELOW 0C INTO EARLY THURSDAY...EXPECT
CLOUDS TO DEVELOP ON BOTH WED AND THU...WITH TEMPS REMAINING
BELOW NORMAL.
COLD POOL ALOFT FINALLY SHIFTS NORTHEASTWARD LATER THU AND THE LL
FLOW WILL VEER TO THE SOUTH. EXPECT A DECREASE IN CLOUD COVER BY
LATE THU...WITH JUST A BIT WARMER TEMPS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN
12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS
WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM
THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE
COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY
AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT
LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO
CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE
FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST.
HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE
FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL
TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
PER RECENT SURFACE AND RADAR DATA THAT IS SHOWING A SLOWER EXIT
OF POSTFRONTAL LIGHT SNOW WEST TO EAST ACROSS THE UPPER OHIO
VALLEY...EXPECT SLOWER IMPROVEMENT FROM IFR TO VFR CONDITIONS LATE
THIS MORNING. HOWEVER STILL EXPECT MAINLY VFR THIS AFTERNOON DUE
TO SUBSIDENCE ASSOCIATED WITH INCOMING HIGH PRESSURE.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE AND VFR CONDITIONS TO CONTINUE THROUGH FRIDAY.
RESTRICTIONS POSSIBLE SATURDAY DUE TO NORTHBOUND WARM FRONTAL RAIN
SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MDZ001.
OH...NONE.
PA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1220 AM EST TUE NOV 27 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 421 PM EST MON NOV 26 2012
MAIN ITEM OF CONCERN FOR THE START OF THE SHORT TERM WILL BE THE
ONGOING LES...MAINLY OVER THE EASTERN CWA.
HIGH PRESSURE RIDGE MOVING OVER THE CWA FROM HIGH OVER THE LOWER
GREAT LAKES AND AHEAD OF A LOW APPROACHING FROM NEAR LAKE WINNIPEG
WILL ALLOW THE WINDS TO BACK TO THE WEST THIS EVENING AND THEN
WEST-SOUTHWEST DURING THE OVERNIGHT HOURS. THIS...COMBINED WITH
LOWERING INVERSION HEIGHTS THIS EVENING WILL CONTINUE TO DIMINISH
LES INTENSITY THROUGH THE EVENING OVER THE WEST. THINK THE AREA THAT
WILL HANG ONTO IT THE LONGEST WILL BE OVER NORTHERN HOUGHTON
COUNTY...UNDER INCREASED CONVERGENCE WITH THE BACKING WINDS. AS THE
WINDS CONTINUE TO BACK TO THE SOUTH WEST...HIGH RES MODELS
INDICATING A STRONGER BAND OF LAKE EFFECT SNOW BECOMING PARALLEL TO
OR RIGHT OVER THE WESTERN KEWEENAW SHORELINE FROM THE UPPER
ENTRANCE TO EAGLE HARBOR. WITH THE LOWER INVERSION AND
DRIER AIR ALOFT INITIALLY...DON/T THINK THE INTENSITY WILL BE TOO
STRONG...BUT COULD SEE A BRIEF INCREASE LATE TONIGHT AS DEEPER
MOISTURE ARRIVES AHEAD OF THE APPROACHING LOW/FRONT. IF THE
SOUTHWEST FLOW WASN/T PRODUCING AS MUCH WAA...H850 TEMPS RISING TO
-9C BY 12Z TUESDAY AND LOWERING LOW LEVEL LAPSE RATES...WOULD BE
CONCERNED ABOUT HIGHER SNOW AMOUNTS. LAKE EFFECT SNOW
PARAMETER ALSO SHOWING THIS QUICK UPTICK IN ACTIVITY LATE
TONIGHT AND THEN QUICKLY DIMINISHING TOWARDS DAYBREAK
WITH THE WAA.
AS FOR THE EAST...EXPECT NORTHWEST WIND LES...AIDED BY THE
CONVERGENCE OVER THE EASTERN LAKE FROM A SURFACE TROUGH...TO
CONTINUE OVER THE NEXT SEVERAL HOURS IN THE MUNISING TO GRAND MARAIS
AREA. MODELS SEEM TO BE STRUGGLING WITH THE STRENGTH OF THE
TROUGH...BUT THE RAP HAS HAD A DECENT HANDLE ON IT THROUGH THE
DAY...DUE TO BETTER INITIALIZATION OF LOW LEVEL WINDS...AND WILL
FOLLOW THAT FOR THE NEAR TERM. RADAR ESTIMATES OF 1-2 IN/HR
SNOW IN THAT AREA OVER THE LAST COUPLE OF HOURS AND WILL KEEP THE
LES WARNING GOING THROUGH 03Z TONIGHT. AFTER 03Z...H950-900 WINDS
BACK TO THE WEST-NORTHWEST AND START PUSH THE STRONGER BAND OFF TO
THE EAST. THIS SHOULD ACCELERATE THROUGH THE OVERNIGHT HOURS...AS
WINDS BECOME WESTERLY AND THEN WEST-SOUTHWEST LATE. STILL EXPECT
THERE TO BE SOME HEAVIER SNOW IN THIS BAND...BUT THE TRANSIENT
NATURE WILL KEEP ACCUMULATIONS LIMITED AFTER 03Z. COULD NEED A BRIEF
ADVISORY ON THE BACK SIDE OF THE WARNING FOR ALGER AND NORTHERN
SCHOOLCRAFT...BUT WITH IT QUICKLY WINDING DOWN AND SPS THIS EVENING
SHOULD COVER IT. WITH THE SNOW AMOUNTS SHOWN ON RADAR...HAVE BUMPED
UP SNOW AMOUNTS THROUGH 3Z...WITH 5-7IN BETWEEN MUNISING AND
SHINGLETON.
WEAK LOW PRESSURE SYSTEM CURRENTLY TO THE WEST OF LAKE WINNIPEG AND
ASSOCIATED COLD FRONT WILL SWEEP ACROSS WESTERN LAKE SUPERIOR LATE
TUESDAY MORNING THROUGH TUESDAY EVENING. WITH THE SOUTHWEST FLOW
IN PLACE ON TUESDAY MORNING...EXPECT THE MAIN SNOW TO BE OCCURRING
OVER WESTERN/NORTHERN LAKE SUPERIOR AND POTENTIALLY RIGHT ALONG THE
NORTHWEST SHORELINE OF KEWEENAW COUNTY. LOW-MID CLOUDS SHOULD BE
PUSHING INTO THE AREA AHEAD OF THIS SYSTEM ON TUESDAY MORNING...SO
EXPECT MUCH OF THE AREA TO BE CLOUDY...ALTHOUGH THERE COULD BE SOME
BREAKS OVER THE EAST DEPENDING ON HOW THICK THE 6-10KFT DECK IS.
WITH DECENT H850 WAA MOVING THROUGH COULD ALSO SEE SOME
ISOLATED/SCATTERED SNOW SHOWERS MOVING OVER THE WESTERN LAKE AND
FAR WESTERN UPPER MI DURING THE MORNING. THEN...WITH THE ARRIVAL OF
THE WEAK SHORTWAVE...ASSOCIATED HEIGHT FALLS...AND H850-500 Q-VECTOR
CONV AND WAA OVER THE WESTERN HALF OF THE CWA IN THE
AFTERNOON...THINK THERE WILL BE ENOUGH TO PRODUCE SCATTERED SNOW
SHOWERS OVER THE WESTERN/CENTRAL CWA DURING THE AFTERNOON. THE
STRONGEST SNOW SHOWERS WILL LIKELY BE OVER THE KEWEENAW
PENINSULA...WHERE WINDS WILL VEER DURING THE AFTERNOON AND PUSH ANY
LES BAND OVER THE WESTERN LAKE ONSHORE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 421 PM EST MON NOV 26 2012
TUESDAY NIGHT...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE
CLIPPER SHORTWAVE TROUGH INTO WRN UPPER MI AT 00Z/WED. AS THE SHRTWV
AND ASSOCIATED COLD FRONT MOVES THROUGH...WINDS WILL VEER FROM SW TO
NW. WITH FAVORABLE 850-700 MB MOISTURE...850 MB TEMPS AROUND
-11C...AND LOW LEVEL CONVERGENCE NEAR THE FRONT ..EXPECT A PERIOD OF
MODERATE TO HEAVY LAKE EFFECT SNOW TO MOVE THROUGH THE WEST IN THE
EVENING AND THEN FOCUS MAINLY OVER THE NE CWA LATE WED NIGHT.
SNOWFALL AMOUNTS MAY APPROACH ADVY CRITERIA OF AROUND 4 INCHES...IN
HIGHER TERRAIN OVER THE WEST SOUTH OF HOUGHTON AND OVER EASTERN
ALGER INTO NRN LUCE COUNTIES.
WEDNESDAY...THE LES SHOULD DIMINISH FROM WEST TO EAST AS A SFC RIDGE
BUILDS INTO THE AREA WITH BACKING WINDS AND DROPPING INVERSION
HEIGHTS. THE BEST CHANCE FOR SIGNIFICANT ACCUMULATIONS WILL REMAIN
OVER THE FAR NE CWA IN THE MORNING (NE LUCE COUNTY) WHERE THE HIGHER
RES MODELS INDICATE POTENTIAL FOR GREATEST LOW LEVEL CONV WITH
300-310 FLOW.
WED NIGHT INTO THU...AS A SHRTWV MOVES THROUGH NRN ONTARIO AND HIGH
PRES BUILDS FROM NRN ALBERTA AND SASK INTO NRN ONTARIO...ANOTHER
WEAK COLD FRONT WILL DROP THROUGH THE NRN GREAT LAKES. BEHIND THE
FRONT...WINDS ARE EXPECTED TO VEER TO THE NORTHEAST. WITH ONLY
SHALLOW COLD AIR MASS AND DRY ACYC FLOW INTO THE AREA...ONLY SLIGHT
CHANCE POPS WERE INCLUDED FOR -SHSN LATE WED NIGHT INTO THU MORNING
OVER MAINLY N CNTRL UPPER MI.
FRIDAY THROUGH MONDAY...THE MODELS WERE IN GENERAL AGREEMENT WITH A
TRANSITION TO A MORE ZONAL PATTERN BRINGING MILD PACIFIC AIR INTO
THE REGION. AS WAA AND MOISTURE ADVECTION INCREASES FRIDAY...ENOUGH
COLD AIR IS EXPECTED TO LINGER SO THAT MAINLY -SN WOULD BE EXPECTED
WITH ANY LIGHT PCPN. THE ECMWF WAS STRONGER/SLOWER WITH A SHORTWAVE
RESULTING IN A MORE PRONOUNCED WARM/MOIST SURGE SATURDAY COMPARED TO
THE GFS/GEM. FOLLOWING THE RAIN CHANCES SAT...MOIST/MILD AIR IS
EXPECTED TO LINGER INTO EARLY NEXT WEEK WHEN ADDITIONAL RAIN CHANCES
ARE POSSIBLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1219 AM EST TUE NOV 27 2012
LAKE EFFECT -SHSN WILL CONTINUE TO AFFECT KCMX FOR THE NEXT SEVERAL
HRS WITH VIS VARYING BTWN MVFR AND IFR. LATER IN THE NIGHT...WINDS
SHOULD BACK SUFFICIENTLY TO PUSH LAKE EFFECT TO THE N OF KCMX...
LEAVING BEHIND MVFR CIGS AND LINGERING FLURRIES DUE TO WEAK
DISTURBANCE PASSING ACROSS THE AREA. AT KIWD/KSAW...VFR CONDITIONS
WILL BE THE RULE. THIS AFTN/EVENING...NEXT COLD FRONT WILL PUSH
ACROSS THE UPPER LAKES...BRINGING A RETURN OF LAKE EFFECT SHSN TO
KCMX. EXPECT A PERIOD OF IFR CONDITIONS WITH FROPA LATE AFTN AT
KCMX. AT KIWD...MVFR CONDITIONS WILL RETURN LATE IN THE AFTN AS
FRONT PASSES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EST MON NOV 26 2012
WITH GENERALLY WEAK CLIPPER SYSTEMS BEING THE MAIN WIND PRODUCERS
OVER THE NEXT FEW DAYS...WINDS OF 20 TO 30 KTS WILL BE COMMON BUT NO
GALES ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
216 PM CST TUE NOV 27 2012
.DISCUSSION...
THERE WAS SOME ENHANCEMENT OF THE -SN ACROSS THE NE FA EARLIER
TODAY AS A FAIRLY POTENT SHRTWV MOVED SE THRU EASTERN MN. MOST OF THIS
ACTIVITY HAS MOVED INTO NW WI...WITH MAINLY CLDS HOLDING ON IN THE
EASTERN 1/3 OF THE FA. WHERE SKIES CLEARED EARLIER IN PORTIONS OF
CENTRAL/SW/SC MN...TEMPS MANAGED TO RISE INTO THE 40S...WITH AREAS
IN THE EAST HOLDING IN THE UPPER 20S/LOWER 30S WHERE CLOUDS
REMAIN. THE WEAK FRONT WAS MOVING ACROSS THE NW FA AS OF 2 PM. THE
MAIN COLD FRONT REMAINS ACROSS N MN WHERE TEMPS HAVE HELD STEADY
OR FELL A DEGREE OR TWO.
THE MAIN FORECAST CONCERN IS WHETHER FREEZING DRIZZLE DEVELOPS
LATE THU/EARLY FRI ACROSS MOST OF THE FA...WITH THE BEST POTENTIAL
ACROSS EC MN AND WC WI WHERE THE DEPTH OF THE MOISTURE AND
STRONGER WAA WILL RESIDE. IT IS HARD TO FORECAST FREEZING
DRIZZLE...OR DRIZZLE DUE TO THE FACT THAT MODELS DO NOT GENERATE
THIS SCENARIO. THE MODELS USUALLY INCREASE THE MOISTURE...BUT WITH
VERY WEAK LIFT IN A DRIZZLE TYPE ENVIRONMENT...LITTLE OR NO
PRECIPITATION IS FORECAST. DUE TO UNCERTAINTIES IN THE DEPTH OF
THE MOISTURE AND WHETHER A STRONGER WAA REGIME DEVELOPS...HAVE
KEPT THE FORECAST IN LINE WITH ONLY AREAS OF FOG WITH PATCHY
FREEZING DRIZZLE. BUT...AGAIN THIS IS HIGHLY DEPENDENT ON THE
DEPTH OF THE MOISTURE WHERE SUPERCOOLED WATER DROPLETS FORM AND
WHETHER THESE DROPLETS COMBINED TO GENERATE DRIZZLE. ONE ITEM THAT
IS DIFFERENT IN THE MODELS THAN IN PREVIOUS RUNS IS THE FACT THAT
A VERY SMALL AREA OF QPF HAS DEVELOPED NEAR THE FA. THIS TELLS ME
THAT THERE IS A FAIRLY DEEP MOISTURE LAYER IN THE MODELS AND
ENOUGH LIFT TO GENERATE A HUNDREDTH OF AN INCH. WILL CONTINUE TO
ADVERTISE THE FREEZING DRIZZLE POTENTIAL IN THE HWO...MAINLY DUE
TO THE TIMING FOR THE MORNING COMMUTE.
PAST FRIDAY...THE ABNORMALLY MILD PATTERN WILL CONTINUE WITH
THICKNESS VALUES RISING ABV THE 550DM MARK FOR A GOOD PART OF THE
WEEKEND. SOME OF THE ENSEMBLE MEMBERS IN THE EC BIAS CORRECTED
ELEMENT HAS 60S FOR SUNDAY/MONDAY IN THE METRO AREA. ALTHOUGH THIS
TYPE OF PATTERN IS VERY CONDUCIVE FOR RECORD HIGHS FOR THIS TIME
OF YEAR...THE PROBLEM I HAVE IS THE LOW SUN ANGLE AND THE AMT OF
HRS OF POTENTIAL SUNSHINE. EVEN IF WE GET SUNSHINE...FROM MORNING
LOWS PROGGED TO FALL INTO THE 30S. A 30 DEGREE CHANGE FROM ONLY 6
HRS OF TRUE ISOLATION IS HARD TO COME BY. THE DRY PATTERN ALSO
SEEMS APPARENT WITH THE MAIN STORM TRACK TO THE NORTH OF THE
INTERNATIONAL BORDER. BOTH THE EC/GFS DO FORECAST A COLD FRONTAL
PASSAGE NEXT TUESDAY...THE MEAN UPPER FLOW WILL CONTINUE TO BE
MILD WITH ONLY A SMALL COOL DOWN AT BEST. ..JLT..
&&
.AVIATION... /18Z TAF ISSUANCE/
A WEAK FRONT WILL PASS ACROSS THE AREA THIS AFTERNOON. AT 18Z THE
FRONT EXTENDED FROM NORTHEAST MINNESOTA TO SIOUX FALLS SOUTH
DAKOTA. THE RAP AND LOCAL WRF 925-850MB PROGS INDICATING THE
POTENTIAL FOR A BKN DECK AROUND 5-6KFT...AND POSSIBLY SCT-BKN MVFR
CLOUDS MAINLY AT KAXN AND KSTC. FURTHERMORE SATELLITE AND
OBSERVATIONS SHOW CEILINGS AROUND 015-020 NORTH AND WEST OF OUR
TERMINALS WITH THAT DECK MOVING SOUTHEAST. THE QUESTION IS HOW FAR
SOUTH AND EAST WE ADVECT THOSE CEILINGS. KAXN AND KSTC ARE A
DEFINITE. FURTHER SOUTH AND EAST ARE NOT AS CLEAR CUT. THE RAP AND
NAM PUSH THIS MOISTURE TO KRWF/KMSP BUT AM NOT CONFIDENT ENOUGH AT
THIS POINT TO HAVE A CEILING IN TIME FOR THE CEILING AOB 050...BUT
IT IS A POSSIBILITY. AFTER 12Z WEDNESDAY ONLY MID AND HIGH LEVEL
CLOUDS WILL BE PRESENT.
WINDS SHIFT TO THE WEST AND NORTHWEST BETWEEN 21Z TODAY AND 02Z
WEDNESDAY AS THE FRONT PASSES. WINDS DURING THE DAY WEDNESDAY WILL
BE LIGHT AND VARIABLE BEFORE BECOMING SOUTHERLY IN THE LATE AFTERNOON.
KMSP...MID CLOUDS INCREASE AND LOWER TO ABOUT 050 AS THE FRONT APPROACHES.
THERE IS ALSO A SMALL PROBABILITY THAT A SCT MVFR LEVEL AROUND 3K
FT WILL DEVELOP WITH THE FROPA AND LINGER UNTIL 03Z WEDNESDAY.
MIGHT SEE A FEW GUSTS TO AROUND 15KTS THIS AFTERNOON BEFORE THE
FRONT MOVES THROUGH. OTHERWISE SPEEDS GENERALLY BETWEEN 5 AND 10
KTS AND THEN LIGHT AND VARIABLE AFTER 12Z WEDNESDAY.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS LIGHT AND VARIABLE BECOMING S AT 5-10 KTS.
THU...VFR. WINDS ENE AT 5-10 KTS.
FRI...CHC FOR MVFR OR LOWER CIGS/VSBYS WITH FOG AND FZDZ POSSIBLE
IN THE MORNING. WINDS E 10 KTS.
SAT...CHANCE FOR MVFR OR LOWER CIGS/VSBYS WITH LIGHT RAIN...MAYBE
STARTING OUT AS LIGHT SNOW EARLY IN THE MORNING. WINDS S 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/DRL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
115 PM CST TUE NOV 27 2012
.UPDATE...
.AVIATION... /18Z TAF ISSUANCE/
A WEAK FRONT WILL PASS ACROSS THE AREA THIS AFTERNOON. AT 18Z THE
FRONT EXTENDED FROM NORTHEAST MINNESOTA TO SIOUX FALLS SOUTH
DAKOTA. THE RAP AND LOCAL WRF 925-850MB PROGS INDICATING THE
POTENTIAL FOR A BKN DECK AROUND 5-6KFT...AND POSSIBLY SCT-BKN MVFR
CLOUDS MAINLY AT KAXN AND KSTC. FURTHERMORE SATELLITE AND
OBSERVATIONS SHOW CEILINGS AROUND 015-020 NORTH AND WEST OF OUR
TERMINALS WITH THAT DECK MOVING SOUTHEAST. THE QUESTION IS HOW FAR
SOUTH AND EAST WE ADVECT THOSE CEILINGS. KAXN AND KSTC ARE A
DEFINITE. FURTHER SOUTH AND EAST ARE NOT AS CLEAR CUT. THE RAP AND
NAM PUSH THIS MOISTURE TO KRWF/KMSP BUT AM NOT CONFIDENT ENOUGH AT
THIS POINT TO HAVE A CEILING IN TIME FOR THE CEILING AOB 050...BUT
IT IS A POSSIBILITY. AFTER 12Z WEDNESDAY ONLY MID AND HIGH LEVEL
CLOUDS WILL BE PRESENT.
WINDS SHIFT TO THE WEST AND NORTHWEST BETWEEN 21Z TODAY AND 02Z
WEDNESDAY AS THE FRONT PASSES. WINDS DURING THE DAY WEDNESDAY WILL
BE LIGHT AND VARIABLE BEFORE BECOMING SOUTHERLY IN THE LATE AFTERNOON.
KMSP...MID CLOUDS INCREASE AND LOWER TO ABOUT 050 AS THE FRONT APPROACHES.
THERE IS ALSO A SMALL PROBABILITY THAT A SCT MVFR LEVEL AROUND 3K
FT WILL DEVELOP WITH THE FROPA AND LINGER UNTIL 03Z WEDNESDAY.
MIGHT SEE A FEW GUSTS TO AROUND 15KTS THIS AFTERNOON BEFORE THE
FRONT MOVES THROUGH. OTHERWISE SPEEDS GENERALLY BETWEEN 5 AND 10
KTS AND THEN LIGHT AND VARIABLE AFTER 12Z WEDNESDAY.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS LIGHT AND VARIABLE BECOMING S AT 5-10 KTS.
THU...VFR. WINDS ENE AT 5-10 KTS.
FRI...CHC FOR MVFR OR LOWER CIGS/VSBYS WITH FOG AND FZDZ POSSIBLE
IN THE MORNING. WINDS E 10 KTS.
SAT...CHANCE FOR MVFR OR LOWER CIGS/VSBYS WITH LIGHT RAIN...MAYBE
STARTING OUT AS LIGHT SNOW EARLY IN THE MORNING. WINDS S 10 KTS.
&&
.PREV DISCUSSION...
/ISSUED 603 AM CST TUE NOV 27 2012/
OVERVIEW...NOT MANY CHANGES WITH THE FORECAST UPDATE THIS MORNING.
INCREASED TEMPS A FEW DEGREES IN THE EXTENDED AND SOME GUIDANCE
SUGGESTS WE COULD BE EVEN WARMER FRIDAY THROUGH MONDAY BEFORE A
STRONG COLD FRONT MOVES THROUGH THIS TIME NEXT WEEK. WE REMAIN IN
A DRY PATTERN WITH MUCH BETTER CHANCES FOR RAIN/SNOW IN NORTHERN
MINNESOTA AND NORTH OF THE CANADIAN BORDER.
IT`S JUST AS COLD IN NORTHERN KANSAS AS IT IS HERE THIS MORNING
GIVEN THE POSITION OF THE SURFACE HIGH AND THE ADVANCE OF HIGH
CLOUDS ACROSS MN/WI SINCE MIDNIGHT. THE 27.00Z MPX SOUNDING SHOWED
WARMING THROUGH ALMOST THE ENTIRE DEPTH OF THE ATMOSPHERE OVER
THE PAST 24 HOURS AND THAT`S EVEN WITH FLOW THAT IS PREDOMINATELY
NORTHWEST. WE`RE ALREADY SEEING A CHANCE EARLY THIS MORNING AT LOW
LEVELS. THE WOOD LAKE, MN PROFILER STILL SHOWS NORTHWEST 500/250MB
WINDS...BUT THE SURFACE TO 850MB FLOW IS NOW WEST-SOUTHWEST AND WE
ARE GETTING WARM AIR ADVECTION. IT WILL BE MUCH MORE MILD TODAY.
THE GFS/EC SEEMS IN BETTER AGREEMENT NOW WITH TIMING OF SHORTWAVE
ENERGY THURSDAY NIGHT. NEITHER SOLUTION SUGGESTS MUCH ACCUMULATING
PRECIP...BUT IT`S SOMETHING TO WATCH. FORECAST SOUNDINGS AND
INDICATE MOSTLY LIGHT RAIN OR DRIZZLE GIVEN THE LACK OF DEEP
MOISTURE. SURFACE TEMPS WILL BE COLD ENOUGH FOR FREEZING DRIZZLE
FOR A TIME AS WELL. AS PREVIOUSLY MENTIONED...THERE IS A STRONG
INFLUX OF MOISTURE AND WARM AIR ADVECTION WITH SATURATION BELOW
850MB.
PRETTY QUIET IN THE EXTENDED WITH ABOVE NORMAL TEMPS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/DRL
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
222 PM CST TUE NOV 27 2012
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
DROPPING SOUTHEAST OVER WESTERN WISCONSIN EARLY THIS AFTERNOON...AND
IS KICKING OFF SNOW SHOWERS OVER THE NW CORNER OF THE STATE. A FEW
SNOW SHOWERS LOOK RATHER BEEFY ON RADAR...AND AN OBSERVATION AT
HAYWARD DROPPED VSBYS DOWN TO A QUARTER MILE BRIEFLY. WILL BE ON
THE LOOK OUT FOR A HISA EVENT THIS AFTERNOON. COLD FRONT IS
TRAILING THE LEAD SHORTWAVE...AND IS POSITIONED FROM THE ARROWHEAD
OF MINNESOTA TO NORTHERN SOUTH DAKOTA. A WIDESPREAD LOW STRATUS
DECK EXISTS IMMEDIATELY BEHIND THIS FRONT...AND A FEW FLURRIES HAVE
BEEN NOTED ON THE OBS THERE TOO. AS SHORTWAVE ACTIVITY AND THE COLD
FRONT CROSS THE REGION TONIGHT...CLOUDS AND PRECIP CHANCES ARE THE
MAIN FORECAST CONCERNS.
TONIGHT...WEAK SHORTWAVE ACTIVITY WILL SWING ACROSS THE REGION
TONIGHT AND PUSH A COLD FRONT ACROSS THE AREA. THOUGH MOISTURE IS
GENERALLY LACKING...MOISTURE IS GREATER TO THE NORTH. RADARS SUGGEST
N-C WISCONSIN WILL SEE LIKELY SNOW SHOWERS THIS EVENING SO WILL
RAISE POPS A BIT. NOT SURE HOW FAR SOUTH TO BRING A MENTION OF
FLURRIES...BUT NORTH OF ROUTE 29 SEEMS LIKE A LOGICAL DIVIDER BASED
ON RADAR TRENDS. BEHIND THE FRONT...A LOW STRATUS DECK HAS BEEN
ADVANCING SOUTHEAST. MODELS SCOUR OUT THE LOW LEVEL MOISTURE
TONIGHT AND SUGGEST THIS STRATUS DECK MAY ONLY REACH N-C WISCONSIN.
GIVEN THE SOLID LOOK TO THE STRATUS AND THE COLD ADVECTION TO TAKE
PLACE...THINK THIS IS TOO OPTIMISTIC AND WILL BRING THE STRATUS DECK
INTO CENTRAL WISCONSIN AS WELL. BY THE TIME IT GETS THERE LATE
TONIGHT...ENOUGH DRY AIR AND DOWNSLOPING SHOULD KEEP THE STRATUS
FROM REACHING NE AND E-C WISCONSIN. NORTHWEST WINDS WILL KEEP SNOW
SHOWERS AND FLURRIES GOING OVER VILAS COUNTY THROUGH THE NIGHT
HOWEVER. A STRONGER PRESSURE GRADIENT SHOULD KEEP THE BL MIXED
ENOUGH TO GO WITH WARMER TEMPS COMPARED TO LAST NIGHT. WILL GO WITH
LOW TEENS NORTH TO NEAR 20 SE.
WEDNESDAY...PRETTY QUIET AS HIGH PRESSURE RIDGE AXIS WORKS ACROSS
THE STATE. BACKING LOW LEVEL WINDS WILL FORCE LAKE CLOUDS TO LIFT
OFF TO THE NORTHEAST AND AWAY FROM N-C WISCONSIN DURING THE
MORNING. IF LOW STRATUS DOES STICK AROUND INTO WEDNESDAY
MORNING...THINK THE INCOMING RIDGE AXIS WILL CAUSE ANY CLOUDS TO
BREAK UP EARLY IN THE PERIOD. MOST OF THE AREA SHOULD SEE MOSTLY
SUNNY CONDITIONS FOR MUCH OF THE DAY. HIGHS RANGING FROM THE MID
20S NORTH TO LOWER 30S SOUTH.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. WINTER IS SLOW
TO ARRIVE THIS YEAR AND THE MEDIUM RANGE MODELS SUGGEST THAT THE
MILD WEATHER PATTERN WILL CONTINUE.
DRY NORTHWEST FLOW IS EXPECTED THROUGH THURSDAY WITH TEMPERATURES
RISING ABOVE NORMAL FOR THIS TIME OF THE YEAR. UPPER FLOW IS
FORECAST TO BECOME ZONAL FRIDAY THROUGH SUNDAY WITH SOME
OVERRUNNING LIGHT SNOW...DRIZZLE OR FREEZING DRIZZLE THURSDAY NIGHT
AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH THE FLOW.
MOISTURE IS SHALLOW AND NOT VERY ABUNDANT SO DO NOT EXPECT MUCH. A
MORE SIGNIFICANT SHORTWAVE IS EXPECTED SATURDAY AFTERNOON OR
EVENING WHICH SHOULD HAVE A BIT MORE MOISTURE AS WELL.
TEMPERATURES WILL BE WELL ABOVE FREEZING SO WHATEVER FALLS SHOULD
BE RAIN.
UPPER RIDGE REALLY BUILDS MONDAY AND SOUTHERLY LOW LEVEL FLOW
INCREASES TOO. 925MB TEMPERATURES FORECAST TO RISE TO +10C MONDAY
AFTERNOON AND EVENING WHICH COULD HELP DRIVE TEMPERATURES INTO THE
50S IF THERE IS ANY SUNSHINE AT ALL. A COLD FRONT WILL MOVE
THROUGH MONDAY NIGHT AND BRING SLIGHTLY COOLER AIR FOR TUESDAY.
&&
.AVIATION...EXPECT MAINLY VFR CONDITIONS...THOUGH MVFR CIGS AND
SNOW SHOWERS POSSIBLE IN NORTHCENTRAL WISCONSIN THIS EVENING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/RDM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
200 PM CST TUE NOV 27 2012
.SHORT TERM...THROUGH FRIDAY
200 PM CST TUE NOV 27 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THIS EVENING AS
WELL AS THURSDAY NIGHT INTO FRIDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING FROM THE BRITISH COLUMBIA COAST SOUTHWARD THROUGH THE
WESTERN U.S....WHILE TROUGHING WAS PRESENT FROM SOUTHEAST CANADA
INTO THE GREAT LAKES. IN THE NORTHWEST FLOW BETWEEN THE RIDGE AND
TROUGH...A SHORTWAVE TROUGH WAS NOTED OVER NORTHERN MINNESOTA.
ISENTROPIC LIFT DEPICTED ON THE 285-295K SURFACES AHEAD OF THE
SHORTWAVE HAS RESULTED IN SCATTERED-BROKEN ALTOSTRATUS ACROSS THE
FORECAST AREA. FARTHER NORTH...SNOW HAS BEEN FALLING ACROSS NORTHERN
MINNESOTA INTO NORTHERN WI WHERE THE DPVA AND ISENTROPIC LIFT
FORCING IS STRONGEST...ALONG WITH BETTER LOW LEVEL SATURATION PER
12Z INL SOUNDING. A COLD FRONT REPRESENTING THE SHORTWAVE AT THE
SURFACE EXTENDED FROM NORTHEAST MINNESOTA INTO SOUTHEAST SOUTH
DAKOTA. SOUTHWEST WINDS AHEAD OF THE FRONT HAS HELPED PULL WARMER
AIR INTO THE REGION...NOTED BY 925MB TEMPS THAT HAVE CLIMBED AT MPX
FROM -11C AT 00Z TO -4C AT 12Z PER SOUNDINGS. READINGS HAVE CLIMBED
INTO THE LOW TO MID 30S IN MOST LOCATIONS. BEHIND THE FRONT ACROSS
SOUTH DAKOTA...READINGS ARE NOT THAT MUCH COOLER. HOWEVER...ACROSS
SOUTHERN MANITOBA WHERE HIGH PRESSURE SITS...READINGS ARE IN THE
LOWER TEENS. 925MB TEMPS IN THIS AREA ARE -14 TO -18C PER RAP
ANALYSIS.
TONIGHT AND WEDNESDAY...THE UPPER LEVEL PATTERN IS FORECAST TO
DEAMPLIFY SOME ACROSS THE CONUS...IN RESPONSE TO A PORTION OF EAST
PACIFIC TROUGHING MOVING INTO THE WESTERN U.S.. BY 00Z THURSDAY...
500MB HEIGHTS WILL HAVE RISEN NEARLY 120 METERS OVER THE FORECAST
AREA. SUBSIDENCE ASSOCIATED WITH THESE HEIGHT RISES SHOULD KEEP THE
MAJORITY OF THE NEXT 24 HOURS QUIET. THE ONLY CONCERN IS WITH THE
SHORTWAVE OVER NORTHERN MINNESOTA DROPPING SOUTHEAST THROUGH
NORTHERN WISCONSIN THIS EVENING. THE 280-285K ISENTROPIC LIFT
HELPING TO PRODUCE THE SNOW ACROSS NORTHERN MINNESOTA WILL ACCOMPANY
THE SHORTWAVE SOUTHEASTWARD. RIGHT NOW IT APPEARS THE BULK OF THE
SNOW SHOULD STAY NORTH OF THE FORECAST AREA...PER MODEL CONSENSUS
AND SHORTWAVE TRACK...BUT AM CONCERNED AT LEAST SOME FLURRIES COULD
OCCUR OVER TAYLOR/CLARK. HAVE ADDED THE FLURRIES INTO THE FORECAST.
EVENING SHIFT WILL NEED TO WATCH THE SNOW PROGRESSION. OTHERWISE...
THE COLD FRONT LOOKS TO MOVE THROUGH MUCH OF THE FORECAST AREA BY
09Z. 925MB TEMP PROGS SUGGEST A PORTION OF THAT COLDER AIR IN
SOUTHERN MANITOBA WILL MAKE IT SOUTH INTO THE FORECAST AREA...WITH
TEMPS AT 12Z WEDNESDAY RANGING FROM -2C OVER NORTHEAST IOWA TO -8 TO
-10C IN TAYLOR COUNTY. AS SUCH...THE COLDEST READINGS TONIGHT ARE IN
TAYLOR COUNTY. THE WINDS AND SOME STRATUS CLOUDS BEHIND THE FRONT
SHOULD MITIGATE THE TEMPERATURE FALL SOMEWHAT...THOUGH. THE 925MB
TEMPS HOLD FAIRLY STEADY THROUGH ABOUT 18Z...DUE TO HIGH PRESSURE
SLIDING ACROSS... THEN BEGIN TO CLIMB. MIXING TO THE 925MB TEMPS
RESULTS IN HIGHS IN THE UPPER 20S TO NEAR 40...COLDEST ACROSS TAYLOR
AND CLARK COUNTIES. THIS MIXING SHOULD BE DOABLE DESPITE SOME
INCREASE IN HIGH CLOUDS DEPICTED IN THE AFTERNOON.
WEDNESDAY NIGHT AND THURSDAY...SOME MORE 500MB HEIGHT RISES ARE
FORECAST OVER THE AREA...IN RESPONSE TO THE WESTERN U.S. RIDGE
FLATTENING OUT AND BEING PUSHED EASTWARD BY THE PORTION OF THE EAST
PACIFIC TROUGH HEADING INTO THE DAKOTAS BY 00Z FRIDAY. SUBSIDENCE
AGAIN ASSOCIATED WITH THESE HEIGHT RISES SHOULD BE ENOUGH TO KEEP
THE AREA DRY. THIS SUBSIDENCE DOES LOOK TO CLEAR THE CIRRUS OUT
WEDNESDAY NIGHT. HOWEVER...AN INCREASE IN CIRRUS IS EXPECTED ACROSS
MUCH OF THE AREA ON THURSDAY AS THAT SHORTWAVE TROUGH COMES INTO THE
DAKOTAS. IN ADDITION...A MASS OF LOW CLOUDS IS PROGGED TO COME INTO
NORTHERN PORTIONS OF THE FORECAST AREA THURSDAY AFTERNOON. THESE ARE
IN THE WAKE OF A COLD FRONTAL PASSAGE...FORECAST TO DROP SOUTH
THROUGH THE AREA MOSTLY DURING THE MORNING. 925MB TEMPS CLIMB NICELY
WEDNESDAY NIGHT AHEAD OF THAT FRONT DROPPING SOUTH...TOPPING OUT
BETWEEN 2C AND -2C BY 12Z. THIS WARM ADVECTION COMBINED WITH A
SOUTHERLY BREEZE SHOULD HELP KEEP TEMPERATURES UP. A BLEND OF
GUIDANCE SEEMS REASONABLE FOR LOWS SUGGESTING MAINLY IN THE 20S. FOR
THURSDAY...925MB TEMPS FALL TO 0 TO -4C AT 18Z THURSDAY...THOUGH THE
WARMER NIGHT AND SOME FILTERED SUNSHINE WILL ALLOW TEMPERATURES TO
BE ABOUT 5 DEGREES WARMER THAN WEDNESDAY.
THURSDAY NIGHT AND FRIDAY...THE SHORTWAVE TROUGH ACROSS THE DAKOTAS
MODELS FORECAST TO COME ACROSS THE AREA FRIDAY MORNING. MODELS VARY
ON STRENGTH OF THE TROUGH...WITH THE 27.12Z GFS STRONGEST AND 27.12Z
NAM WEAKEST. HOWEVER...THE STRENGTH OF THE SHORTWAVE APPEARS TO HAVE
LITTLE SENSIBLE IMPACT ON THE WEATHER AS THE MID-LEVELS OF THE
ATMOSPHERE ARE SUGGESTED TO BE QUITE DRY. IN FACT...MUCH OF THE
ACTION LOOKS TO OCCUR BELOW 850MB. THE POST-FRONTAL LOW CLOUD MASS
DROPPING SOUTH THURSDAY AFTERNOON MODELS ARE IN GOOD AGREEMENT IN
HAVING IT ENCOMPASS LOCATIONS FROM I-90 NORTH BY 06Z FRIDAY. THE LOW
CLOUD DECK MAY EVEN DRIFT FARTHER SOUTH BETWEEN 06-12Z TO ENCOMPASS
MOST OF THE AREA. THE REASON THIS IS SO IMPORTANT IS THAT ISENTROPIC
LIFT PLOTS SHOW WEAK LIFT ON THE 280-285K SURFACES THURSDAY NIGHT
INTO FRIDAY MORNING. THE LIFT IN THE LOW CLOUD DECK COULD RESULT IN
SOME LIGHT FREEZING DRIZZLE DEVELOPING. SINCE THIS HAS BEEN A
CONSISTENT SIGNAL...HAVE INCLUDED THE MENTION OF IT IN THE FORECAST.
GIVEN THE IMPACTS FROM JUST A TINY BIT OF FREEZING DRIZZLE...MAY
NEED AN ADVISORY AT SOME POINT. ALSO ADDED A FOG MENTION AREA WIDE
FOR 06-18Z FRIDAY GIVEN THE VERY LOW CEILINGS PROGGED. CLOUDS LOOK
TOUGH TO CLEAR TOO FRIDAY AFTERNOON AS A GENERAL EAST-SOUTHEAST LOW
LEVEL FLOW PERSISTS. THUS...ANTICIPATING MUCH OF THIS 24 HOUR PERIOD
TO BE CLOUDY. THE CLOUDS WILL LIMIT THE DIURNAL FALL AND RISE...AND
IT IS WORTH NOTING THAT 925MB TEMPS CHANGE VERY LITTLE THROUGH
FRIDAY SUGGESTING LITTLE IN THE WAY OF ADVECTION. THUS...
TEMPERATURES SHOULD NOT CHANGE A WHOLE LOT. ONLY HAVE ABOUT A 10
DEGREE CHANGE FROM NIGHT AND DAY IN THE FORECAST.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
200 PM CST TUE NOV 27 2012
VERY GOOD MODEL AGREEMENT EXISTS AND REMAINS AMONGST THE 27.12Z
ECMWF/GFS/UKMET/CANADIAN AND GFS ENSEMBLES THROUGH MUCH OF THE LONG
TERM FORECAST...BOTH AT THE SURFACE AND ALOFT. THE UPPER LEVEL FLOW
THROUGH THE SHORT TERM PERIOD THAT IS TRANSITIONING FROM NORTHWEST
TO ZONAL BECOMES SOUTHWESTERLY FOR THE WEEKEND. THE FLOW THEN
AMPLIFIES AS A PROGRESSIVE DEEP TROUGH MARCHES ACROSS THE WEST AND
CENTRAL U.S. EARLY NEXT WEEK. MAIN PRECIPITATION TIMES OF NOTE ARE
ON SATURDAY INTO SATURDAY EVENING...AS WELL AS MONDAY INTO MONDAY
NIGHT. THE FIRST IS ASSOCIATED WITH A SHORTWAVE TROUGH COMING
THROUGH THE SOUTHWESTERLY FLOW. A SURGE OF GULF OF MEXICO MOISTURE
ACCOMPANIES THE TROUGH AS IT MOVES INTO THE AREA...ENOUGH TO LIKELY
PRODUCE A LOW LEVEL STRATUS DECK AS WELL AS SOME LIGHT
PRECIPITATION. RIGHT NOW MAYBE WE GET UP TO A TENTH OF AN INCH AT
MOST. THE MONDAY INTO MONDAY NIGHT PERIOD IS MORE INTERESTING HAVING
A DYNAMIC DEEP TROUGH COMING ACROSS. 850MB WINDS INCREASE TO 40-50
KT HELPING TO BRING 850MB DEWPOINTS UP TO 8C OR SO. ONE ISSUE IS
THAT THE SATURATION AGAIN IS ALL IN THE LOW LEVELS...AND THE
ATMOSPHERE IS CAPPED...THUS ANOTHER LIGHT RAIN/DRIZZLE EVENT WOULD
OCCUR. OVERALL...THOUGH...CONFIDENCE IN EITHER EVENT PRODUCING
WIDESPREAD QPF IS FAIRLY LOW AT THIS POINT SINCE THE DYNAMICAL
FORCING IS ALL NORTH OF THE AREA. THUS...PRECIPITATION CHANCES ARE
IN THE 20-40 RANGE.
TEMPERATURES ARE MORE INTERESTING HERE IN THE LONG TERM PERIOD.
925MB TEMPS ARE FORECAST BETWEEN 3-7C ON SATURDAY...AS MUCH AS 6-10C
ON SUNDAY PER 27.00Z/12Z ECMWF AND 10-14C BY LATE IN THE DAY MONDAY.
THE INCOMING STRATUS DECK ON BOTH SATURDAY AND MONDAY WILL LIKELY
HOLD BACK THE POTENTIAL FOR MIXING TO 925MB. HOWEVER...ADVECTION
ALONE SHOULD BE ABLE TO PUSH READINGS INTO THE MID 40S TO LOW 50S ON
SATURDAY AND INTO THE 50S EVERYWHERE ON MONDAY PER MODEL CONSENSUS.
SHOULD ANY UNEXPECTED SUNSHINE OCCUR...HIGHS COULD EASILY BE HIGHER.
MONDAYS FORECAST HIGHS ARE ONLY A FEW DEGREES BELOW RECORDS...59 AT
ROCHESTER AND 61 AT LA CROSSE. SUNDAY HAS THE BEST OPPORTUNITY FOR
SUNSHINE...AND IF THE ECMWF IS CORRECT...WE COULD EASILY CLIMB INTO
THE 50S AND PERHAPS REACH 60 IN SOUTHERN AREAS. HAVE BUMPED UP HIGHS
ABOVE THE CONSENSUS TO RANGE FROM THE MID 40S TO MID 50S. IT APPEARS
RECORDS ON SUNDAY SHOULD BE SAFE WITH ROCHESTER AT 62 AND LA CROSSE
AT 64. FOR TUESDAY...DECENT COOLING COMES IN THANKS TO THE UPPER
TROUGH SLIDING INTO THE AREA. FOLLOWED THE CONSENSUS HIGHS IN THE
40S FOR NOW.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1211 PM CST TUE NOV 27 2012
VFR CONDITIONS ARE FORECAST FOR THE TAF SITES THROUGH THE PERIOD.
A WEATHER SYSTEM WILL PASS THROUGH SOUTHERN CANADA AND SLIDE A
COLD FRONT IN FROM THE NORTH TO PROVIDE A WIND SHIFT. WHILE AHEAD
OF THE FRONT CLOUDS ARE ALL VFR...THERE IS SOME SMALL PROBABILITY OF
A LOW-LEVEL CLOUD DECK ACROSS MOVING IN BEHIND THE FRONT
OVERNIGHT. THESE CLOUDS ARE CURRENTLY SHIFTING SOUTH FROM ND AND
NWRN MN.
CONFIDENCE IS NOT HIGH THAT THIS WILL CREATE A CEILING AT
THE TAF SITES...BUT CONFIDENCE IS HIGH ENOUGH TO TREND TOWARD
CLOUDS OVERNIGHT THAT COULD FORM AN MVFR CIG. THUS...HAVE INCLUDED
A LOWER MVFR SCT CLOUD DECK IN THE FORECAST LATE TONIGHT. THIS
WILL BE THE MAIN FORECAST PROBLEM FOR FUTURE TAF FORECASTS...AND
CUSTOMERS WITH INTERESTS IN THE DAYBREAK TIME RANGE WILL WANT TO
MONITOR THOSE. AN IFR CEILING CANNOT BE RULED OUT FOR THAT TIME
FRAME EITHER...BUT THE PROBABILITIES SEEM LOW AT THIS TIME FOR IFR
CIGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
200 PM CST TUE NOV 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1046 PM CST MON NOV 26 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 1033MB HIGH
PRESSURE SYSTEM MOVING SOUTHEAST OVER THE NORTH-CENTRAL GREAT
PLAINS. NORTHWEST FLOW ALONG THE THE FRONT SIDE OF THE HIGH
CONTINUES TO PRODUCE LAKE CLOUDS AND FLURRIES OVER N-C WISCONSIN
EARLY THIS AFTERNOON...BUT THESE CLOUDS SHOULD START TO ERODE LATER
IN THE DAY AS THE SURFACE HIGH BRINGS DRIER AIR INTO THE STATE. LOW
LEVEL WARM ADVECTION IS OCCURRING UPSTREAM OVER NORTH DAKOTA AND
SOUTHERN CANADA WHERE THERE ARE A FEW REPORTS OF SNOW SHOWERS AND
FLURRIES. AS THIS WARM ADVECTION ARRIVES LATE TONIGHT INTO
TUESDAY...CLOUDS AND SNOW CHANCES ARE THE MAIN FORECAST CONCERNS.
TONIGHT...NORTHWEST FLOW TO PREVAIL TONIGHT ACROSS THE WESTERN GREAT
LAKES. WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WILL PASS OVER
NORTHERN ILLINOIS THIS EVENING WHILE HIGH PRESSURE PASSES ACROSS THE
STATE OF WISCONSIN. AS LOW LEVEL WINDS BACK AROUND TO THE
WEST...THEY WILL PUSH DRIER AIR ACROSS NORTHERN WISCONSIN AND LAKE
EFFECT CLOUDS SHOULD EXIT TO THE NORTHEAST. SO SHOULD HAVE A MOSTLY
CLEAR EVENING AND WINDS HAVE A CHANCE TO DECOUPLE...WHICH WOULD HELP
TEMPS PLUMMET OVER N-C WISCONSIN ONCE SKIES CLEAR. TEMPS UPSTREAM
IN MINNESOTA FELL NEAR ZERO...AND THINK POTENTIAL IS THERE FOR THAT
TO OCCUR. WILL TREND TEMPS LOWER. AFTER MIDNIGHT...A WEAK
SHORTWAVE WILL DROP SOUTHEAST ACROSS SOUTHERN CANADA AND WILL SEND
SCT-BKN LOW AND MID CLOUDS ACROSS THE NORTHWEST PART OF THE STATE.
FLURRIES NOTED OVER SOUTH-CENTRAL CANADA SHOULD STAY TO OUR NORTH.
ONCE THE CLOUDS ARRIVE...TEMPS MAY REBOUND A BIT. LOWS IN THE MID
SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR LAKE MICHIGAN.
TUESDAY...THE SHORTWAVE ENERGY WILL DROP INTO THE WESTERN GREAT
LAKES ON TUESDAY AND WILL PUSH A COLD FRONT INTO NORTHWEST WISCONSIN
DURING THE AFTERNOON. LOW LEVEL WARM ADVECTION CLOUDS WILL LIKELY
LIFT OUT TO THE NORTHEAST IN THE MORNING. PLENTY OF MID AND HIGH
CLOUDS WILL BE AROUND TO MAKE THIS A PARTLY SUNNY TO MOSTLY CLOUDY
DAY. AHEAD OF THE FRONT...LOW CLOUDS WILL BE ON THE INCREASE OVER
N-C AND CENTRAL WISCONSIN IN THE AFTERNOON. PREVIOUS SHIFT ADDED A
CHANCE OF SNOW SHOWERS...AND THIS LOOKS GOOD. HIGHS IN THE MIDDLE
20S NORTH TO THE LOWER 30S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. LOOKS LIKE A
FAIRLY QUITE PERIOD OF WEATHER WITH LITTLE OR NO SNOW AND
TEMPERATURES WARMING ABOVE NORMAL.
NORTHWEST UPPER FLOW WILL KEEP TEMPERATURES NEAR NORMAL WEDNESDAY
BUT THEN UPPER FLOW WILL BACK AND BECOME ZONAL BY THE END OF THE
WEEK. A COUPLE OF WEAK SHORTWAVES ARE EXPECTED TO MOVE THROUGH
THE UPPER FLOW FRIDAY AND SATURDAY SETTING UP SOME LIGHT
OVERRUNNING PRECIPITATION. IT MAY BE COLD ENOUGH FOR SOME SNOW
FRIDAY BUT AFTER THAT IT LOOKS TOO WARM FOR ANYTHING BUT LIGHT
RAIN.
SOUTHERLY SURFACE FLOW WILL BRING UP WARM AND MOIST AIR OVER THE
COLD GROUND AND MAY PRODUCE DENSE FOG AT SOME POINT LATE IN THE
WEEK.
&&
.AVIATION...CLOUDS WILL BE ON THE INCREASE OVERNIGHT...BUT CIGS
ARE EXPECTED TO REMAIN VFR. SOME PATCHY FLURRIES MAY IMPACT THE
RHI TAF SITE LATE TONIGHT INTO EARLY TUESDAY. SCT-BKN SKY COVER
AND VFR CONDITIONS WILL CONTINUE THROUGH TUESDAY...WITH SW WINDS
GUSTING TO AROUND 20 KTS DURING THE AFTERNOON. SOME LLWS IS POSSIBLE
DURING THE EVG HOURS...IN ADVANCE OF AN APPROACHING COLD FRONT.
THE FRONT IS EXPECTED TO MOVE THROUGH RHI AROUND 03Z/WED...AND
AUW/CWA AROUND 04Z/WED. SCT SNOW SHOWERS AND FLURRIES WILL DEVELOP
ACROSS NC WI DURING THE EVG...AND MVFR CIGS WILL LIKELY ARRIVE
IN THE WAKE OF THE COLD FRONT.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1021 AM EST THU NOV 29 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS TO OUR SOUTH TODAY, BEFORE A WEAK COLD FRONT
MOVES ACROSS THE AREA FROM THE NORTH FRIDAY MORNING. STRENGTHENING
CANADIAN HIGH PRESSURE WILL FOLLOW ACROSS NEW ENGLAND THEN INTO
THE CANADIAN MARITIMES FROM FRIDAY INTO THE WEEKEND. A WARM FRONT
IS EXPECTED TO LIFT NORTH OF THE AREA SUNDAY, POSSIBLY FOLLOWED
BY ANOTHER COLD FRONT FROM THE NORTH ON MONDAY. A COLD FRONT IS
EXPECTED TO MOVE IN FROM THE WEST LATE TUESDAY INTO EARLY
WEDNESDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SANDY CORRECTION: REVIEWING DATA WE FOUND THE MAX WIND GUST AT SANDY
HOOK NOS TIDE LOCATION WAS 69 MPH...642 PM ON THE 29TH. (DATA STOPPED
FLOWING THERE AT ABOUT 736 PM. THAT CORRECTS DOWN FROM THE PREVIOUS
REPORT OF 77 MPH AT 715PM). THE TEXAS TECH 2.5 METER STICK MEASUREMENT
NEARBY AROUND 830P OF 75 MPH AND THE 87 MPH WXFLOW MESONET OB AT
ABOUT 835PM BOTH CONTINUE AS IS.
DID NOT RESEND THE PNS...ITS A MONTH SINCE THE STORM OCCURRED PLUS
WE HAD ADDED LOWEST PRES AND SURGE DATA THAT IS NOT IN THE ECLAIRS
PROGRAM WHERE-FROM THE RAIN/SNOW/WIND DATA ARE PRODUCED. I COULD
NOT ACCESS THAT PARTICULAR PNSFILE IN AWIPS ATTM...THOUGH IT
CONTINUES TO RESIDE ON THE WEB.
934AM ESTF UPDATE RAN THE FCST WITH THIS AFTN AND ADJUSTED SKYCOVER
EVEN HIGHER WITH A RESULTANT MORE DEFINED WORDING IN SOME OF THE
ZONES NORTH OF PHILADELPHIA.
TODAY...PERIODS OF THICK HIGH CLOUDS ARE STREAMING ESE ACROSS THE
AREA TODAY...MOSTLY FROM ILG LATITUDE NORTH. 12Z NAM AND CURRENT RUC13
RUNS CONTINUE THE THEME FROM SUCCESSIVE PRIOR MULTI MODEL RUNS.
RGEM AND RUC RH AS WELL AS GFS MOS DO NOT ALL CAPTURE THE VISUAL
SEE-THROUGH IMPACT. THICK CLOUD COVER SHOULD THIN LATE THIS AFTERNOON
BUT DUE TO SHORTER DAYLIGHT HOURS...THIS CLOUD DECK MAY MODIFY THE
WARMING RATE AND MAY FORCE A SLIGHTLY COOLER DAY THAN CURRENTLY
FCST...ESPECIALLY THE STILL SNOW COVERED NE PA AND NW NJ.
THE LOW LEVELS ARE DRY...SO NO PRECIPITATION IS EXPECTED FROM THE
MID LEVEL CLOUDINESS. 850 MB TEMPERATURES WOULD SUPPORT HIGHS
RANGING FROM THE UPPER 30S TO MID 40S FROM NORTH TO SOUTH. SINCE
MODEL SOUNDINGS SUGGEST MIXING FROM 850 MB...HIGHS ARE BASED ON
THESE NUMBERS. THE HIGHS ABOVE ACROSS CLOSER TO THE COOLER GFS MOS
VALUES.
THE GRADIENT FLOW SHOULD SUPPORT WINDS BETWEEN 10 AND 15 MPH. MODEL
SOUNDINGS ARE SUGGESTING THAT GUSTS TO 20 MPH ARE POSSIBLE THIS
AFTERNOON WITH THE PASSAGE OF THE SHORT WAVE...AS THE DEPTH OF THE
MIXED LAYER OVER LAND INCREASES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
THE MID LEVEL CLOUDINESS SHOULD EXIT THIS EVENING...AND THE GRADIENT
FLOW SHOULD RELAX BY MID EVENING. HOWEVER...IT DOES NOT APPEAR AS
THOUGH THE FLOW BECOMES CALM...SO TEMPERATURES ARE NOT EXPECTED TO
PLUMMET THIS EVENING LIKE THEY DID WEDNESDAY EVENING.
ANOTHER SHORT WAVE IN THE MID LEVEL FLOW WILL TRY TO PUSH A COLD
FRONT SOUTH TOWARD THE REGION AFTER 0600 UTC FRIDAY. RIGHT NOW...IT
APPEARS AS THOUGH THE BEST MID LEVEL FORCING AHEAD OF THE SHORT WAVE
WILL REMAIN NORTH AND WEST OF THE AREA THROUGH DAYBREAK FRIDAY. THIS
SHOULD ALSO KEEP ANY PRECIPITATION NORTH OF THE AREA AS WELL.
MODEL SOUNDINGS SUGGEST THAT STRATOCUMULUS LEVEL CLOUDINESS SHOULD
APPROACH NORTHERN ZONES LATE TONIGHT. ELSEWHERE...SKIES SHOULD
REMAIN MOSTLY CLEAR. FOR THE MOST PART...LOWS WERE BASED ON THE MOS
BLEND.
FRIDAY...BACKDOOR CF SAGS SOUTHWARD INTO THE FORECAST AREA. LIGHT
SOUTHWEST WIND SHIFTING EAST NORTHEAST IN THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A SERIES OF BACKDOOR TYPE COLD FRONTAL PASSAGE AND SHORT WAVES ARE
EXPECTED DURING THE LONG TERM PORTION OF THE FORECAST, FOLLOWED BY A
TYPICAL COLD FRONTAL PASSAGE FROM THE WEST LATE IN THE PERIOD.
POST BACK DOOR COOL FRONT...ANY LIFT/MOISTURE IS EXPECTED TO LAG
BEHIND THE BOUNDARY AND LIKELY BE CONFINED ACROSS THE NORTHERN
HALF OF THE CWA. THEREFORE, WE HAVE ANY PRECIP CHANCES OVERNIGHT
FRIDAY. HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST SATURDAY,
DEVELOPING A RETURN FLOW ACROSS THE AREA. THERE MAY BE ENOUGH
MOISTURE REMAINING ACROSS THE AREA THAT SOME LIGHT PRECIP COULD
CONTINUE TO BE SQUEEZED OUT ACROSS THE AREA AS A SHORT WAVES
CONTINUES TO SLIDE ACROSS THE AREA. IT`S POSSIBLE THAT THIS MAY
END UP BEING MORE DRIZZLE/FLURRIES THAN RAIN/SNOW FRIDAY NIGHT AND
SATURDAY, BUT WE KEEP IT RAIN/SNOW AS THE PRECIP TYPE.
PRECIP CHANCES DIMINISH SATURDAY NIGHT INTO EARLY SUNDAY, BEFORE
INCREASING ONCE AGAIN LATER ON SUNDAY INTO SUNDAY NIGHT. A WARM
FRONT IS FORECAST TO LIFT NORTH OF THE AREA ON SUNDAY, FOLLOWED BY A
SHORT WAVE ALOFT LATER SUNDAY INTO SUNDAY NIGHT. THERE MAY BE ENOUGH
MOISTURE COMBINED WITH THE ENHANCED LIFT TO CREATE SOME
PRECIPITATION ACROSS THE AREA. TEMPERATURES ARE FORECAST TO BE
WARM ENOUGH TO KEEP IT ALL RAIN.
ANOTHER WEAK BACKDOOR TYPE COLD FRONT IS FORECAST TO APPROACH THE
AREA ON MONDAY, HOWEVER, ITS PASSAGE IS EXPECTED TO BE A DRY ONE.
THEREFORE, THE FORECAST IS DRY FOR MONDAY THROUGH MONDAY NIGHT.
FINALLY, A TYPICAL COLD FRONT IS EXPECTED TO APPROACH THE AREA FROM
THE WEST LATER TUESDAY, AND CROSS THE AREA TUESDAY NIGHT INTO
WEDNESDAY MORNING. PRECIPITATION CHANCES INCREASE WITH THE PASSAGE
OF THE FRONTAL BOUNDARY, WHICH IS CURRENTLY EXPECTED TUESDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE WARM ENOUGH TO KEEP P-TYPE
ALL RAIN.
TEMPERATURES ARE EXPECTED TO BE CLOSE TO NORMAL FRIDAY, BEFORE
RISING OVER THE WEEKEND INTO EARLY NEXT WEEK. TEMPERATURES LATE IN
THE WEEKEND INTO EARLY NEXT WEEK ARE EXPECTED TO BE SEVERAL DEGREES
ABOVE NORMAL, THEN DROP BACK CLOSER TO NORMAL BEHIND THE FRONTAL
BOUNDARY FOR THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR OCNL CIGS AOA 10000 FEET...MOSTLY NORTH OF KILG. WEST
WINDS OF 8 TO 12 KNOTS ARE EXPECTED TODAY...WITH A FEW GUSTS NEAR
18 KNOTS POSSIBLE IN THE AFTERNOON (BETWEEN 1700 AND 2100 UTC) AT
THE KPHL METRO AIRPORTS.
TONIGHT...VFR CONDITIONS ARE EXPECTED WITH SOUTHWEST WINDS OF 5
KNOTS OR LESS. SOME HIGH AND MID LEVEL CLOUDINESS IS POSSIBLE
TOWARD DAYBREAK FRIDAY AHEAD OF A BACKDOOR COLD FRONT.
FRIDAY...VFR. A PERIOD OF CIGS AOA 8000 FT EXPECTED DURING MIDDAY
JUST BEHIND THE SURFACE WIND SHIFT-COLD FRONT. MVFR CIGS MAY DEVELOP
IN THE INCREASING ENE FLOW BEHIND THE FRONT...NEAR AND NORTH OF
KSMQ.
OUTLOOK...
FRIDAY NIGHT-SATURDAY...MOSTLY VFR.
SATURDAY NIGHT-SUNDAY NIGHT...MVFR CONDITIONS POSSIBLE.
MONDAY...MVFR CONDITIONS POSSIBLE EARLY...IMPROVING TO VFR.
&&
.MARINE...
SCA DISCONTINUED WITH THE 10 AM CWF/MWW ISSUANCE.
WEST WINDS MAY BRIEFLY INCREASE LATE THIS AFTERNOON OR EVENING IN
THE NNJ WATERS BUT FOR NOW NOT ANTICIPATING ANY FURTHER SCA THROUGH
FRIDAY.
OUTLOOK...
WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS FOR
FRIDAY NIGHT THROUGH SATURDAY AS WEAK HIGH PRESSURE BUILDS DOWN ACROSS
THE WATERS FROM THE NORTH. WINDS AND WAVES MAY APPROACH ADVISORY
LEVELS AGAIN LATE SUNDAY THROUGH SUNDAY NIGHT, AS THE SOUTHERLY
FLOW INCREASES BEHIND A WARM FRONT THAT LIFTS TO OUR NORTH.
CONDITIONS ON MONDAY SHOULD REMAIN BELOW ADVISORY LEVELS AS WEAK
COLD FRONT MOVES ACROSS THE WATERS FROM THE NORTH AND WEAK HIGH
PRESSURE REMAINS TO OUR SOUTH.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG/HAYES
SHORT TERM...DRAG/HAYES
LONG TERM...ROBERTSON
AVIATION...DRAG/HAYES/ROBERTSON
MARINE...DRAG/HAYES/ROBERTSON 1020A
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
949 AM EST THU NOV 29 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS TO OUR SOUTH TODAY, BEFORE A WEAK COLD FRONT
MOVES ACROSS THE AREA FROM THE NORTH FRIDAY MORNING. STRENGTHENING
CANADIAN HIGH PRESSURE WILL FOLLOW ACROSS NEW ENGLAND THEN INTO
THE CANADIAN MARITIMES FROM FRIDAY INTO THE WEEKEND. A WARM FRONT
IS EXPECTED TO LIFT NORTH OF THE AREA SUNDAY, POSSIBLY FOLLOWED
BY ANOTHER COLD FRONT FROM THE NORTH ON MONDAY. A COLD FRONT IS
EXPECTED TO MOVE IN FROM THE WEST LATE TUESDAY INTO EARLY
WEDNESDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SANDY CORRECTION: REVIEWING DATA WE FOUND THE MAX WIND GUST AT SANDY
HOOK NOS TIDE LOCATION WAS 69 MPH...642 PM ON THE 29TH. (DATA STOPPED
FLOWING THERE AT ABOUT 736 PM. THAT CORRECTS DOWN FROM THE PREVIOUS
REPORT OF 77 MPH AT 715PM). THE TEXAS TECH 2.5 METER STICK MEASUREMENT
NEARBY AROUND 830P OF 75 MPH AND THE 87 MPH WXFLOW MESONET OB AT
ABOUT 835PM BOTH CONTINUE AS IS.
DID NOT RESEND THE PNS...ITS A MONTH SINCE THE STORM OCCURRED PLUS
WE HAD ADDED LOWEST PRES AND SURGE DATA THAT IS NOT IN THE ECLAIRS
PROGRAM WHERE-FROM THE RAIN/SNOW/WIND DATA ARE PRODUCED. I COULD
NOT ACCESS THAT PARTICULAR PNSFILE IN AWIPS ATTM...THOUGH IT
CONTINUES TO RESIDE ON THE WEB.
934AM ESTF UPDATE RAN THE FCST WITH THIS AFTN AND ADJUSTED SKYCOVER
EVEN HIGHER WITH A RESULTANT MORE DEFINED WORDING IN SOME OF THE
ZONES NORTH OF PHILADELPHIA.
TODAY...PERIODS OF THICK HIGH CLOUDS ARE STREAMING ESE ACROSS THE
AREA TODAY...MOSTLY FROM ILG LATITUDE NORTH. 12Z NAM AND CURRENT RUC13
RUNS CONTINUE THE THEME FROM SUCCESSIVE PRIOR MULTI MODEL RUNS.
RGEM AND RUC RH AS WELL AS GFS MOS DO NOT ALL CAPTURE THE VISUAL
SEE-THROUGH IMPACT. THICK CLOUD COVER SHOULD THIN LATE THIS AFTERNOON
BUT DUE TO SHORTER DAYLIGHT HOURS...THIS CLOUD DECK MAY MODIFY THE
WARMING RATE AND MAY FORCE A SLIGHTLY COOLER DAY THAN CURRENTLY
FCST...ESPECIALLY THE STILL SNOW COVERED NE PA AND NW NJ.
THE LOW LEVELS ARE DRY...SO NO PRECIPITATION IS EXPECTED FROM THE
MID LEVEL CLOUDINESS. 850 MB TEMPERATURES WOULD SUPPORT HIGHS
RANGING FROM THE UPPER 30S TO MID 40S FROM NORTH TO SOUTH. SINCE
MODEL SOUNDINGS SUGGEST MIXING FROM 850 MB...HIGHS ARE BASED ON
THESE NUMBERS. THE HIGHS ABOVE ACROSS CLOSER TO THE COOLER GFS MOS
VALUES.
THE GRADIENT FLOW SHOULD SUPPORT WINDS BETWEEN 10 AND 15 MPH. MODEL
SOUNDINGS ARE SUGGESTING THAT GUSTS TO 20 MPH ARE POSSIBLE THIS
AFTERNOON WITH THE PASSAGE OF THE SHORT WAVE...AS THE DEPTH OF THE
MIXED LAYER OVER LAND INCREASES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
THE MID LEVEL CLOUDINESS SHOULD EXIT THIS EVENING...AND THE GRADIENT
FLOW SHOULD RELAX BY MID EVENING. HOWEVER...IT DOES NOT APPEAR AS
THOUGH THE FLOW BECOMES CALM...SO TEMPERATURES ARE NOT EXPECTED TO
PLUMMET THIS EVENING LIKE THEY DID WEDNESDAY EVENING.
ANOTHER SHORT WAVE IN THE MID LEVEL FLOW WILL TRY TO PUSH A COLD
FRONT SOUTH TOWARD THE REGION AFTER 0600 UTC FRIDAY. RIGHT NOW...IT
APPEARS AS THOUGH THE BEST MID LEVEL FORCING AHEAD OF THE SHORT WAVE
WILL REMAIN NORTH AND WEST OF THE AREA THROUGH DAYBREAK FRIDAY. THIS
SHOULD ALSO KEEP ANY PRECIPITATION NORTH OF THE AREA AS WELL.
MODEL SOUNDINGS SUGGEST THAT STRATOCUMULUS LEVEL CLOUDINESS SHOULD
APPROACH NORTHERN ZONES LATE TONIGHT. ELSEWHERE...SKIES SHOULD
REMAIN MOSTLY CLEAR. FOR THE MOST PART...LOWS WERE BASED ON THE MOS
BLEND.
FRIDAY...BACKDOOR CF SAGS SOUTHWARD INTO THE FORECAST AREA. LIGHT
SOUTHWEST WIND SHIFTING EAST NORTHEAST IN THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A SERIES OF BACKDOOR TYPE COLD FRONTAL PASSAGE AND SHORT WAVES ARE
EXPECTED DURING THE LONG TERM PORTION OF THE FORECAST, FOLLOWED BY A
TYPICAL COLD FRONTAL PASSAGE FROM THE WEST LATE IN THE PERIOD.
POST BACK DOOR COOL FRONT...ANY LIFT/MOISTURE IS EXPECTED TO LAG
BEHIND THE BOUNDARY AND LIKELY BE CONFINED ACROSS THE NORTHERN
HALF OF THE CWA. THEREFORE, WE HAVE ANY PRECIP CHANCES OVERNIGHT
FRIDAY. HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST SATURDAY,
DEVELOPING A RETURN FLOW ACROSS THE AREA. THERE MAY BE ENOUGH
MOISTURE REMAINING ACROSS THE AREA THAT SOME LIGHT PRECIP COULD
CONTINUE TO BE SQUEEZED OUT ACROSS THE AREA AS A SHORT WAVES
CONTINUES TO SLIDE ACROSS THE AREA. IT`S POSSIBLE THAT THIS MAY
END UP BEING MORE DRIZZLE/FLURRIES THAN RAIN/SNOW FRIDAY NIGHT AND
SATURDAY, BUT WE KEEP IT RAIN/SNOW AS THE PRECIP TYPE.
PRECIP CHANCES DIMINISH SATURDAY NIGHT INTO EARLY SUNDAY, BEFORE
INCREASING ONCE AGAIN LATER ON SUNDAY INTO SUNDAY NIGHT. A WARM
FRONT IS FORECAST TO LIFT NORTH OF THE AREA ON SUNDAY, FOLLOWED BY A
SHORT WAVE ALOFT LATER SUNDAY INTO SUNDAY NIGHT. THERE MAY BE ENOUGH
MOISTURE COMBINED WITH THE ENHANCED LIFT TO CREATE SOME
PRECIPITATION ACROSS THE AREA. TEMPERATURES ARE FORECAST TO BE
WARM ENOUGH TO KEEP IT ALL RAIN.
ANOTHER WEAK BACKDOOR TYPE COLD FRONT IS FORECAST TO APPROACH THE
AREA ON MONDAY, HOWEVER, ITS PASSAGE IS EXPECTED TO BE A DRY ONE.
THEREFORE, THE FORECAST IS DRY FOR MONDAY THROUGH MONDAY NIGHT.
FINALLY, A TYPICAL COLD FRONT IS EXPECTED TO APPROACH THE AREA FROM
THE WEST LATER TUESDAY, AND CROSS THE AREA TUESDAY NIGHT INTO
WEDNESDAY MORNING. PRECIPITATION CHANCES INCREASE WITH THE PASSAGE
OF THE FRONTAL BOUNDARY, WHICH IS CURRENTLY EXPECTED TUESDAY
NIGHT. TEMPERATURES ARE EXPECTED TO BE WARM ENOUGH TO KEEP P-TYPE
ALL RAIN.
TEMPERATURES ARE EXPECTED TO BE CLOSE TO NORMAL FRIDAY, BEFORE
RISING OVER THE WEEKEND INTO EARLY NEXT WEEK. TEMPERATURES LATE IN
THE WEEKEND INTO EARLY NEXT WEEK ARE EXPECTED TO BE SEVERAL DEGREES
ABOVE NORMAL, THEN DROP BACK CLOSER TO NORMAL BEHIND THE FRONTAL
BOUNDARY FOR THE MIDDLE OF NEXT WEEK.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR OCNL CIGS AOA 10000 FEET...MOSTLY NORTH OF KILG. WEST
WINDS OF 8 TO 12 KNOTS ARE EXPECTED TODAY...WITH A FEW GUSTS NEAR
18 KNOTS POSSIBLE IN THE AFTERNOON (BETWEEN 1700 AND 2100 UTC) AT
THE KPHL METRO AIRPORTS.
TONIGHT...VFR CONDITIONS ARE EXPECTED WITH SOUTHWEST WINDS OF 5
KNOTS OR LESS. SOME HIGH AND MID LEVEL CLOUDINESS IS POSSIBLE
TOWARD DAYBREAK FRIDAY AHEAD OF A BACKDOOR COLD FRONT.
FRIDAY...VFR. A PERIOD OF CIGS AOA 8000 FT EXPECTED DURING MIDDAY
JUST BEHIND THE SURFACE WIND SHIFT-COLD FRONT. MVFR CIGS MAY DEVELOP
IN THE INCREASING ENE FLOW BEHIND THE FRONT...NEAR AND NORTH OF
KSMQ.
OUTLOOK...
FRIDAY NIGHT-SATURDAY...MOSTLY VFR.
SATURDAY NIGHT-SUNDAY NIGHT...MVFR CONDITIONS POSSIBLE.
MONDAY...MVFR CONDITIONS POSSIBLE EARLY...IMPROVING TO VFR.
&&
.MARINE...
WILL DISCONTINUE SCA WITH THE 10 AM EXPIRATION AND RUN MWW AND CWF
SHORTLY AFTER 10 AM.
WEST WINDS MAY BRIEFLY INCREASE LATE THIS AFTERNOON OR EVENING IN
THE NNJ WATERS BUT FOR NOW NOT ANTICIPATING ANY FURTHER SCA THROUGH
FRIDAY.
OUTLOOK...
WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS FOR
FRIDAY NIGHT THROUGH SATURDAY AS WEAK HIGH PRESSURE BUILDS DOWN ACROSS
THE WATERS FROM THE NORTH. WINDS AND WAVES MAY APPROACH ADVISORY
LEVELS AGAIN LATE SUNDAY THROUGH SUNDAY NIGHT, AS THE SOUTHERLY
FLOW INCREASES BEHIND A WARM FRONT THAT LIFTS TO OUR NORTH.
CONDITIONS ON MONDAY SHOULD REMAIN BELOW ADVISORY LEVELS AS WEAK
COLD FRONT MOVES ACROSS THE WATERS FROM THE NORTH AND WEAK HIGH
PRESSURE REMAINS TO OUR SOUTH.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ450-
451.
&&
$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG/HAYES 949
SHORT TERM...DRAG/HAYES
LONG TERM...ROBERTSON
AVIATION...DRAG/HAYES/ROBERTSON
MARINE...DRAG/HAYES/ROBERTSON 949