Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 221917
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
217 PM EST SAT NOV 22 2014

.SYNOPSIS...
STRONG HIGH PRESSURE OVER THE MID ATLANTIC REGION WILL GRADUALLY
SHIFT OFFSHORE THROUGH TONIGHT. LOW PRESSURE DEVELOPING OVER THE
SOUTHERN PLAINS WILL MOVE NORTHEASTWARD SUNDAY, PULLING A WARM FRONT
THROUGH OUR REGION SUNDAY NIGHT INTO MONDAY. THE LOW WILL BE NEAR
THE GREAT LAKES TOWARD MONDAY MORNING, AND AS IT MOVES INTO EASTERN
CANADA BY TUESDAY ITS ASSOCIATED COLD FRONT WILL CROSS OUR AREA.
HIGH PRESSURE WILL BUILD IN MONDAY NIGHT AND TUESDAY, THEN AN AREA
OF LOW PRESSURE MAY DEVELOP OFF THE MID ATLANTIC COAST WEDNESDAY
INTO THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
A QUICK UPDATE WAS ISSUED TO ACCOUNT FOR CLOUDS MOVING INTO MANY
AREAS FASTER, AND ALSO TO ADD SOME SPRINKLES AS ENOUGH MID LEVEL
FORCING IS ALLOWING FOR A LITTLE BAND OF PRECIPITATION. THE
LOW-LEVELS ARE RATHER DRY SO MAINLY JUST SOME SPRINKLES.

OTHERWISE AS THE FLOW BACKS SOME MORE IN COMBINATION WITH A SURFACE
HIGH SLIDING TO OUR SOUTHEAST, A LARGE AREA OF WAA WILL OCCUR
THROUGH TONIGHT. THIS IS MORE NOTED TO OUR WEST AND NORTHWEST CLOSER
TO THE CORE OF A LOW-LEVEL JET. THIS WILL MAINTAIN SOME ISENTROPIC
LIFT AS THE WARMING CHIPS AWAY AT THE REMAINING COOLER AIRMASS AT
THE SURFACE. THIS PROCESS WILL LEAD TO AN AREA OF CLOUDINESS
SPREADING EASTWARD ACROSS ABOUT THE NORTHERN HALF OF THE CWA THROUGH
THIS AFTERNOON.

THE WAA AND ASSOCIATED LIFT WITH THE AFOREMENTIONED SHORT WAVE HAS
BEEN GENERATING AN AREA OF LIGHT RAIN AND EVEN SOME MIXED
PRECIPITATION FROM WESTERN/CENTRAL NEW YORK/PENNSYLVANIA. THIS IS
LIFTING NORTHEASTWARD. THERE IS A CHC THAT SOME OF THIS GRAZES OUR
FAR NORTHWESTERN ZONES THROUGH THIS EVENING, HOWEVER WITH THE MAIN
LOW-LEVEL JET PASSING TO OUR NORTH ALONG WITH THE BETTER LIFT THERE,
ANY PRECIPITATION SHOULD BE RATHER LIGHT AND SPOTTY. IN THE FORECAST
SOUNDINGS CONTINUE TO SHOW A RATHER DRY LAYER IN THE LOWEST LEVELS
WHICH WOULD EITHER RESULT IN VIRGA OR SOME EVAPORATIVE COOLING.
THERE IS LITTLE MODEL SUPPORT TO BRING IN MEASURABLE PRECIPITATION,
AND THE WPC QPF IS PRETTY MUCH DRY. SINCE THIS LOOKS LIKE A RATHER
LOW CHC POTENTIAL OF SPOTTY LIGHT FREEZING RAIN AND WITH LOW CONFIDENCE,
WE WILL HOLD OFF ON AN ADVISORY. ANY LIGHT INTENSITY WOULD FAVOR DEW
POINTS INCREASING WITH LESS OF A TEMPERATURE DROP. THIS WILL BE
MONITORED THOUGH AND A MENTION REMAINS IN THE HAZARDOUS WEATHER
OUTLOOK.

AS FOR LOW TEMPERATURES, WE USED AN EVEN NAM/GFS MOS BLEND AND THEN
MADE SOME MINOR TWEAKS. THESE COULD BE TRICKY GIVEN THE LOW DEW
POINTS. HOWEVER THE COMBINATION OF SOME CLOUDS, A LIGHT SOUTHERLY
WIND AND A MODERATING AIRMASS IS EXPECTED TO RESULT IN TEMPERATURES
NOT AS COLD AS LAST NIGHT. THE LAMP/LAV GUIDANCE WAS USED TO HELP WITH
TEMPERATURE AND DEW POINT TRENDS THROUGH THIS EVENING.

&&

.SHORT TERM /SUNDAY/...
AN UPPER-LEVEL TROUGH IS FORECAST TO BE AMPLIFYING DURING SUNDAY
ACROSS THE PLAINS. THIS WILL ALLOW SOME RIDGING TO DEVELOP
DOWNSTREAM, RESULTING IN THE SURFACE HIGH TO BECOME ANCHORED
OFFSHORE. THIS WILL PROVIDE A SOUTHERLY FLOW AND WITH WAA CONTINUING
AND EVEN STRENGTHENING SOME DURING THE DAY, A WARMER DAY IS
ANTICIPATED.

THE LOCATION OF A LOW-LEVEL JET IN COMBINATION OF SOME SHORT WAVE
ENERGY AND ISENTROPIC LIFT SHOULD KEEP ANY MORNING LIGHT
PRECIPITATION FOCUSED TO OUR NORTH. MEANWHILE, A WARM FRONT WILL
CONTINUE TO ORGANIZE TO OUR SOUTH AS LOW PRESSURE CONSOLIDATES IN
THE VICINITY OF THE TENNESSEE VALLEY BY LATE IN THE DAY. WHILE THERE
WILL BE SOME CLOUDS AROUND, SOME THINNING SHOULD OCCUR FOR A TIME
BEFORE AN INCREASE DEVELOPS AGAIN TOWARD EVENING. IT APPEARS THAT
ANY ORGANIZED LIFT REMAINS AWAY FROM OUR AREA, THEREFORE WE WILL
CARRY A DRY FORECAST DURING THE DAYLIGHT HOURS.

AS FOR HIGH TEMPERATURES, A GFS/NAM MOS BLEND WAS GENERALLY USED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A NICE WARMING TREND IS IN STORE AT THE START OF THE EXTENDED PD AS
HIGH PRES MOVES OFFSHORE AND STRONG SWLY FLOW DEVELOPS OVER THE
AREA.

THEN, LOW PRES WILL TAKE SHAPE OVER THE SRN PLAINS AND BEGIN TO
MOVE NEWD. THE WMFNT ASSOCD WITH THIS LOW WILL MOVE THRU THE
REGION SUN NIGHT AS THE LOW REALLY INTENSIFIES OVER THE MIDSECTION
OF THE NATION. THE BEST WAA IS SUN NIGHT AND THIS IS THE WETTEST
PERIOD WITH RAIN, SOME HEAVY AT TIMES. WE GET DRY SLOTTED LATER
MON AND IN THE WARM SECTOR, TEMPS WILL SKYROCKET AND COULD REACH
RECORD VALUES IN SOME LOCATIONS, THEN THE COLD FRONT WILL CROSS
THE REGION MONDAY NIGHT, WITH ANOTHER CHC OF PRECIP MON EVE BEFORE
HIGH PRES BUILD BACK IN FOR LATER MON NIGHT THRU TUE NIGHT.

THEN, ALL EYES TURN TO THE POTENTIAL FOR A COASTAL LOW DEVELOPING
AROUND WED. MODEL SOLNS ARE ALL OVER THE PLACE AND CONFIDENCE IS
MUCH BELOW AVERAGE ATTM. THE CMC IS WELL OFFSHORE WITH VIRTUALLY
NO IMPACT TO OUR REGION. THE GFS INDICATES THE MOST IMPACT FOR OUR
SRN AND ERN LOCATIONS WED INTO WED NIGHT BEFORE THE LOW PULLS AWAY
ON THANKSGIVING, BRINGING A DRY HOLIDAY. THE ECMWF HAS THE
STRONGEST AND MOST WWD SOLN AND WOULD BRING A MOSTLY WET AND WINDY
PERIOD FROM WED INTO WED NIGHT. IT HAS SOME SUPPORT FROM THE
UKMET. ANY WINTRY PRECIP WOULD BE CONFINED TO NRN AND WRN AREAS
AT THE ONSET AND THE END.

WITH THE POTENTIAL FOR SIGNIFICANT IMPACT DUE TO HOLIDAY TRAVEL
AND ONE OF THE BUSIEST AIR TRAVEL DAYS OF THE YEAR, THIS SYS WILL
CONTINUE TO BE WATCHED AND COULD END UP BEING NOTHING OR SOMETHING
SIGNIFICANT. THE ECMWF MADE A DECENT WWD SHIFT FROM 21/12Z TO
22/00Z, THE GFS DID NOT.

AFTER THIS STORM MOVES BY WHETHER FAR OFFSHORE OR CLOSE TO THE
COAST, ANOTHER WK CDFNT MAY BRING SOME PRECIP ERLY FRI.

TEMPS WILL START OFF FAIRLY WARM ON SUNDAY, REACH THEIR ZENITH ON
MON, WITH NEAR RECORD WARMTH, THEN STILL BE NR NRML ON TUE BEFORE
TAKING A NOSE DIVE THRU THE REMAINDER OF THE WEEK.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

REST OF THIS AFTERNOON...VFR CEILINGS SPREADING EASTWARD. A FEW
SPRINKLES WILL BE AROUND MAINLY FROM NEAR THE KPHL METRO ON NORTH
AND WESTWARD. SOUTHWESTERLY WINDS AROUND 10 KNOTS WITH SOME GUSTS TO
20 KNOTS.

TONIGHT...VFR, WITH AREAS OF CEILINGS AT OR ABOVE 5,000 FEET.
SOUTHWESTERLY WINDS DIMINISHING TO 5 KNOTS OR LESS.

SUNDAY...VFR, WITH CEILINGS AT TIMES ABOVE 5,000 FEET. SOUTHWEST
WINDS 5-8 KNOTS, BECOMING SOUTHEAST LATE.

OUTLOOK...
SUN NIGHT THROUGH EARLY MON...VERY POOR FLYING CONDS WITH MVFR
EXPECTED AND IFR PSBL IF NOT PROBABLE IN RAIN. RAIN COULD BE HVY
AT TIMES. E TO SE WIND COULD GUST IN THE 20 TO 25 KT RANGE. MDT TO
HIGH CONFIDENCE.

MON AND MON NIGHT...IMPROVING CONDS BUT STILL SOME MVFR PSBL IN
LINGERING SHWRS. CFP/WSFHT MON EVE. VFR BY EVE IF NOT SOONER. LOW
TO MDT CONFIDENCE.

WEDNESDAY...MUCH UNCERTAINTY DEPENDING ON THE TRACK OF A COASTAL
LOW. COULD BE VFR IF LOW IS FAR ENOUGH EAST OR MVFR/IFR IN RAIN
AND WIND IF LOW IS FAR ENOUGH W. BEST CHC FOR VFR IS WRN AIRPORTS.
BEST CHC FOR DEGRADED CONDS IS ERN AIRPORTS. CONFIDENCE VERY LOW.

&&

.MARINE...
THE SOUTHWESTERLY FLOW ON THE BACKSIDE OF HIGH PRESSURE WILL
INCREASE SOME THROUGH THIS AFTERNOON. SOME GUSTS TO 25 KNOTS SHOULD
OCCUR ESPECIALLY ACROSS THE NORTHERN WATERS, HOWEVER IT MAY BE
GENERALLY MARGINAL. THERE SHOULD BE A BETTER CHC OF GUSTS TO AROUND
25 KNOTS TONIGHT ACROSS THE COASTAL WATERS AS THE PRESSURE GRADIENT
TIGHTENS SOME. WAVE HEIGHTS SHOULD RESPOND THROUGH TONIGHT AND BUILD
UP TO 5 FEET IN THE ATLANTIC, AND MAY BE SLOWER TO DECREASE SUNDAY
MORNING. FOR NOW, A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH 6 AM
SUNDAY MORNING FOR ALL BUT THE DELAWARE BAY.

OUTLOOK...
SUN...NO MARINE HEADLINES ANTICIPATED.

SUN NIGHT THROUGH MON...SCA CONDS ARE EXPECTED AND GALES ARE PSBL
IF NOT PROBABLE INTO ERLY MON AS STRONG LOW PRES IMPACTS THE
WATERS.

MON NIGHT INTO TUE....BACK END SCA CONDS AS SEAS AND WIND SUBSIDE
SLOWLY.

WED...NO MARINE HEADLINES ANTICIPATED.

&&

.CLIMATE...
FOR OUR EIGHT CLIMATE SITES, HERE ARE THE RECORD HIGH TEMPERATURES
FOR NOVEMBER 24TH AND THE MOST RECENT YEAR OF OCCURRENCE.

RECORD HIGHS 11/24:

ACY:  72  SET IN 1999
PHL:  71  SET IN 1979
ILG:  73  SET IN 1979
ABE:  69  SET IN 1931
TTN:  71  SET IN 1979
GED:  75  SET IN 1992
RDG:  69  SET IN 1979
MPO:  64  SET IN 1931

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ450>455.

&&

$$
SYNOPSIS...GORSE/NIERENBERG
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...NIERENBERG
AVIATION...GORSE/NIERENBERG
MARINE...GORSE/JOHNSON/NIERENBERG
CLIMATE...DRAG/KLINE




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