Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 270121
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
921 PM EDT SUN OCT 26 2014

.SYNOPSIS...
A HIGH PRESSURE SYSTEM IN THE OHIO VALLEY WILL RIDGE INTO THE AREA
TONIGHT AND MONDAY AND MOVE OFFSHORE MONDAY NIGHT. A WARM FRONT IS
WILL PASS THROUGH THE AREA TUESDAY FOLLOWED BY THE PASSAGE OF A COLD
FRONT ON WEDNESDAY. ANOTHER HIGH PRESSURE RETURNS INTO THE REGION ON
THURSDAY AND EARLY FRIDAY. A COLD FRONT IS EXPECTED TO MOVE THROUGH
THE NORTHEAST ON FRIDAY. A CANADIAN HIGH PRESSURE SHOULD BUILD
INTO THE EASTERN UNITED STATES NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
SKIES REMAIN CLEAR ACROSS 9/10THS OF THE AREA...WITH THE ONLY
CLOUDS REMAINING ACROSS THE NRN PART OF NJ AND ACROSS MONROE
COUNTY PA. WINDS HAVE SETTLED DOWN ACROSS THE AREA AND TEMPERATURES
ARE FALLING RATHER QUICKLY...EXCEPT ACROSS THE CLOUDY AREAS WHERE
READINGS ARE FALLING SLOWLY. THE SKY COVER WILL DIMINISH ACROSS
THE NORTHERLY AREAS AS WELL AFTER MIDNIGHT.

PATCHY FROST IS POSSIBLE NORTH OF THE MASON-DIXON LINE...BUT SINCE
WE/VE ALREADY EXPERIENCED FREEZING TEMPERATURES IN THIS AREA ON
OCT 20TH, THE GROWING SEASON IS OVER AND SO NO FROST ADVISORIES
HAVE BEEN POSTED. LOW TEMPERATURES ARE EXPECTED TO RANGE FROM THE
LOW TO MID 30S NORTH TO LOW 40S SOUTH.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
WE SHOULD START TO SFC HIGH PRESSURE CRESTS OVER THE REGION
MONDAY MORNING BEFORE SLIDING OFF THE VA/NC COAST MONDAY
AFTERNOON. LIGHT AND VARIABLE WINDS WILL GRADUALLY BECOME
SOUTHERLY BY THE END OF THE DAY. A PLEASANT LATE OCTOBER DAY IS ON
TAP, WITH HIGH TEMPERATURES A FEW DEGREES ABOVE NORMAL FOR THIS
TIME OF YEAR.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE LONG TERM STARTS UNSEASONABLY WARM AND ENDS UNSEASONABLY COOL.
AT THE START OF THE LONG TERM THERE REMAINS DECENT CONSENSUS ABOUT
SHOWERS OCCURRING MAINLY DURING THE DAYTIME ON WEDNESDAY (OR OUR
HIGHEST CHANCES THEN) WITH A RETURN OF NEAR NORMAL TEMPS
FOLLOWING. THE TRANSITION TO COOLER WEATHER AT THE END OF THE LONG
TERM AS NOTED BY THE MID SHIFT REMAINS VOLATILE AS DIFFERING
MODELING SOLUTIONS ARE OR ARE NOT PHASING STREAMS. THE ONE
CONSENSUS THAT THE MEDIUM RANGE MODELS ARE NOW GRAVITATING TOWARD
IS A NORTHERN STREAM DOMINATED SYSTEM WITH LESS IF ANY SOUTHERN
STREAM INVOLVEMENT. THE MOST ROBUST OPERATIONAL RUNS HAVE NOT BEEN
CLOSE TO THEIR RESPECTIVE ENSEMBLE MEAN, NOT YESTERDAY`S 12Z ECMWF
RUN NOR TODAY`S GFS 12Z RUN. LOOKING AT THE BIG PICTURE AND
PATTERN, THE PREDICTED TELECONNECTIVE SWITCH IS RATHER MODEST AND
AS PREVIOUSLY NOTED THE FLOW LOOKS PROGRESSIVE. FAMOUS LAST WORDS,
BUT THIS WOULD FAVOR SHYING AWAY FROM THE MOST ROBUST MODELING
SOLUTIONS, WHICH WE CONTINUED.

THERE MAY SOME WAA/RETURN FLOW HIGH CLOUDS ON MONDAY NIGHT, BUT WITH
LITTLE DPVA PREDICTED OVERNIGHT WE ARE OPTING THIS WILL NOT
PREVENT OUTLYING AREAS FROM RADIATING. WINDS ALOFT ARE INCREASING
AS THE NIGHT PROGRESSES., WE ARE THINKING THE CALMER START WILL
DEVELOP THE INVERSION THAT WILL RESIST THIS. UPSHOT WE ARE GOING
WITH OR BELOW STAT GUIDANCE FOR MIN TEMPS.

NO CHANGE IN THINKING FOR TUE WHICH WILL BE UNSEASONABLY WARM AND
SUNNY. NO CHANGE ALSO IN THE DIFFERENCE BETWEEN SOUNDING FULL SUN
MACROS (UPPER 70S TO MID 80S) AND STAT GUIDANCE MAX TEMPS (MID 60S
TO LOWER 70S). BARRING SOME UNEXPECTED LOW CLOUD DECK ARRIVING
FROM THE LOWER MID ATLANTIC, THE UPSIDE POTENTIAL OVER STAT
GUIDANCE REMAINS RATHER HIGH. THE GRADIENT LOOKS TIGHT ENOUGH FOR
SOME MIXING. PREDICTED 1390 1000-850MB THICKNESSES CONTINUE TO
GENERATE HIGHS OF NEAR 80 IN THE CENTRAL CONUS. THUS WE WILL HAVE
NO CHANGE IN CONTINUITY WITH MAX TEMPS WELL ABOVE STAT GUIDANCE.
RECORD HIGHS ARE MAINLY IN THE LOWER TO MID 80S, LIKELY OUT OF
REACH.

THERE IS TIGHTER MODEL TIMING WITH THE SHOWERS ASSOCIATED WITH THE
COLD FRONT. WHILE THUNDER APPEARS POSSIBLE TUESDAY WEST OF THE
APPALACHIANS, INSTABILITY WANES OVERNIGHT FOR US. THE ENTRANCE
REGION OF THE H2.5 JET REMAINS WELL POSITIONED STARTING TUESDAY
NIGHT, SO WE CONTINUE THE CHANCE OF SHOWERS WEST TOWARD MORNING.
TUESDAY NIGHT WE ARE OPTING TO GO AOA STAT GUIDANCE MIN TEMPS DUE
TO CLOUDS AND THE SOUTHWEST WINDS.

THE PREDICTED GFS SHORT WAVE ON WED LOOKS SPURIOUS. IN A BACKHANDED
SENSE IT SLOWS THE PROGRESSION OF ITS CDFNT THRU OUR CWA BRINGING IT
CLOSER TO A MODELING CONSENSUS TIMING. THAT SHORT WAVE ASIDE, OUR
CWA REMAINS IN THE PREDICTED FAVORABLE ENTRANCE REGION OF THE
250MB JET PLUS PREDICTED DECENT MID LEVEL QVEC CONVERGENCE BY ALL
THE MODELS. OUR POPS REMAIN ABOVE 12HR STAT GUIDANCE WITH TIMING
OF HIGHEST POPS CLOSEST TO MODELING CONSENSUS. DIRECT OPPOSITE OF
TUESDAY, BECAUSE OF CLOUDS AND SHOWERS, WE ARE MUCH MORE
CONSERVATIVE WITH MAX TEMPS.

NO CHANGE TO SHOWER CHANCES ON WEDNESDAY NIGHT. BOTH THE ECMWF AND
GFS START HAVING THAT ANAFRONT LOOK TO THE PCPN LATER WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING AS THEY HINT AT A WAVE ON THE
FRONT. THURSDAY AND THURSDAY NIGHT A RETURN OF SEASONABLE
TEMPERATURES AND VERY LIGHT WINDS TO OUR CWA AS WEAK HIGH PRESSURE
BUILDS ACROSS THE REGION. SOME CAA SC POSSIBLE NORTH ON THURSDAY.

WE DID NOT MAKE TOO MANY CHANGES TO HALLOWEEN INTO SATURDAY WITH
A CFP AND A NORTHERN STREAM LOW INTENSIFYING OVER NEW ENGLAND.
WITH THIS 12Z RUN THE UKMET AND CAN GGEM ARE PLAYING THE PARTS OF
THE MOST EXTREME OR BENIGN SOLUTIONS IN BOTH DIRECTIONS. THE GFS
AND ECMWF ARE NOT THAT FAR APART. WHILE THE GFS IS NOT IN
AGREEMENT WITH ITS GEFS MEAN, THE EC ENSEMBLE INFORMATION ARRIVES
TOO LATE TO INCORPORATE INTO THE FORECAST. SLGT CHC/CHC OF SHOWERS
MAINTAINED FRIDAY/HALLOWEEN AFTERNOON AND NIGHT. COLD ENOUGH FAR
NORTHWEST, IF MOISTURE IS DEEP ENOUGH FOR PCPN, THAT IT WOULD
SNOW. MAINLY DRY BUT VERY BLUSTERY WEEKEND WITH POSSIBLY SOME
IMPROVEMENT WITH THE WINDS (PBLY NOT TEMPERATURES) ON SUNDAY.
GIVEN THE LARGE SD SPREAD ON TEMPS OVER THE WEEKEND, LESS
CONFIDENT THAN AVERAGE ABOUT THEM. HOWEVER, PRECEDING THE CFP
ARRIVAL, HALLOWEEN DAY SHOULD HAVE NEAR SEASONABLE TEMPS.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TONIGHT AND MONDAY...VFR. NORTHWEST WINDS WILL BE 10KT OR LESS
FOR THE REMAINDER OF THE OVERNIGHT HOURS. WEST TO NORTHWEST WINDS
AROUND 10 KT ARE EXPECTED MONDAY...BECOMING SW LATE IN THE DAY AT
THE SAME SPEED.

OUTLOOK...
MONDAY NIGHT THROUGH TUESDAY EVENING...VFR.

LATE TUESDAY NIGHT INTO WEDNESDAY EVENING...SCATTERED SHOWERS WITH A
COLD FRONT. BRIEF MVFR POSSIBLE DURING SHOWERS, BUT PREDOMINATELY
VFR.

WEDNESDAY OVERNIGHT THROUGH THURSDAY NIGHT...VFR.

FRIDAY...PREDOMINATELY VFR. IF CFP OCCURS FASTER, SOME MVFR POSSIBLE.

&&

.MARINE...
TONIGHT...SCA CONDITIONS NO LONGER ACROSS DEL BAY...SO FLAG
DROPPED THERE BEFORE 900 PM. LOW END SCA CONDITIONS CONTINUE OVER
THE OCEAN WITH 3-5 FT SEAS AND GUSTS AROUND 25 KTS. WINDS AND SEAS
WILL DIMINISH OVER THE OCEAN WATERS BY DAWN.

MONDAY...SUB-SCA CONDITIONS EXPECTED AS HIGH PRESSURE MOVES OVER THE
FORECAST WATERS.

OUTLOOK...
MONDAY NIGHT...WELL BELOW SMALL CRAFT ADVISORY CRITERIA.

TUESDAY AND WEDNESDAY...SW FLOW STRENGTHENS TUESDAY. WINDS AND SEAS
MAY APPROACH MARGINAL SCA TUESDAY NIGHT AND WEDNESDAY MORNING BUT
CONFIDENCE IN THIS HAPPENING IS LOW THIS FAR OUT. WINDS BECOME NW
BEHIND A COLD FRONT WEDNESDAY AFTERNOON AND WEAKEN. SEAS MAY REMAIN
ELEVATED NEAR 4-5 FT THOUGH, NECESSITATING A SCA.

WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...SUB SMALL CRAFT ADVISORY
CONDITIONS.

FRIDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED. CONFIDENCE IS
LOWER DUE TO TIMING OF A CFP. A STRONG NORTHWEST FLOW IS ANTICIPATED
BEHIND THIS FRONT.

&&

.FIRE WEATHER...
NORTHWEST WINDS 10 TO 15 MPH WILL SUBSIDE OVERNIGHT AS HIGH
PRESSURE BUILDS OVER THE AREA. THIS WILL RESULT IN WEATHER
CONDITIONS LESS CONDUCIVE TO THE SPREAD OF WILD FIRES. WINDS
GENERALLY IN THE 10 MPH RANGE ON MONDAY COUPLED WITH SLIGHTLY
HIGHER RH VALUES SHOULD LESSEN FIRE WEATHER CONCERNS.

&&

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

&&

$$
SYNOPSIS...GIGI/KLEIN
NEAR TERM...MIKETTA/PO
SHORT TERM...MIKETTA
LONG TERM...GIGI
AVIATION...GIGI/KLEIN/MIKETTA
MARINE...GIGI/KLEIN/MIKETTA/PO
FIRE WEATHER...






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