Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 021328
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
928 AM EDT THU OCT 2 2014

.SYNOPSIS...
HIGH PRESSURE OVER THE CANADIAN MARITIMES WILL INFLUENCE OUR
WEATHER THROUGH FRIDAY. THEN, A STRONG COLD FRONT, ASSOCIATED WITH
POTENT LOW PRESSURE IN ONTARIO, WILL MOVE ACROSS THE AREA FRIDAY NIGHT
INTO SATURDAY MORNING. BEHIND THE FRONT, HIGH PRESSURE WILL BUILD
TO THE SOUTH AND EAST THROUGH MONDAY, THEN A SERIES OF IMPULSES
LOOK TO AFFECT THE REGION THROUGH AT LEAST MIDWEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST ESTF UPDATE MAINLY TO ADJUST LOW POPS AND SKY COVER BASED
ON LATEST DATA AND TREND. SLIGHTLY MORE OFFSHORE POPS AND ENDING
SOONER. WITH CLOUDS INDICATING MORE OF AN EARLY BREAK SOUTHWEST
AS THE STRATOCU DECK HAS BEEN SLOW TO MOVE IN PLUS THE INCREASING
SUNSHINE AND THE LOW PULLING FARTHER OFFSHORE WILL WORK AGAINST
THE SOUTHWEST ADVECTION CONTINUING FOR MUCH LONGER. CONVECTIVE
TEMPS ARE STILL WITHIN REACH BASED ON THE MORNING SOUNDINGS, SO
SOME SELF DESTRUCT SUN WILL BE OCCURRING THERE. MORNING SOUNDINGS
AND CONVECTIVE TEMPS OFF THOSE SOUNDINGS ARE SUPPORTING CURRENT
PREDICTED MAXIMUM TEMPERATURES.


OVERNIGHT WATER VAPOR LOOP SHOWS A WELL-DEFINED SPIN IN THE
ATMOSPHERE THAT IS ASSOCIATED WITH AN UPPER-LEVEL LOW OVER SOUTHERN
NEW ENGLAND. THE LOW IS FORECAST TO MOVE OFFSHORE TODAY.

MARINE LAYER AND STRATOCU HAS BEEN ESTABLISHED ACROSS THE REGION
OVER THE PAST 30 HOURS AS A PERSISTENT NORTHEASTERLY FLOW AROUND THE
LOW HAS DRAWN COOL/MOIST AIR FROM THE ATLANTIC MOISTURE INLAND.
THESE CLOUDS ARE EXPECTED TO LINGER OVER THE AREA ONCE AGAIN TODAY.
THERE SHOULD BE AN OPPORTUNITY TO SEE MORE APPRECIABLE BREAKS IN THE
CLOUDS, PARTICULARLY SOUTH AND WEST OF PHILLY LATER THIS MORNING.
HOWEVER, DEEPER MIXING AT THESE SUNNIER LOCATIONS WILL RESULT IN
REDEVELOPMENT OF STRATOCU DURING THE AFTERNOON.

ANY LINGERING PRECIP NEAR THE COAST WILL SHIFT OFFSHORE BY MID
MORNING AS THE UPPER LOW PULLS AWAY FROM THE AREA.

FORECAST MAX TEMPS ARE IN THE 70S TODAY EXCEPT FOR THE UPPER 60S
ALONG THE NJ COAST (WHERE THICKER CLOUD COVER WILL LIMIT DAYTIME
HEATING) AND IN THE HIGHER ELEVATIONS OF NW NJ AND THE POCONOS.
LEANED TOWARD THE WARMER MET GUIDANCE FOR PHILLY AND POINTS SOUTH
AND WEST (WHERE LESS CLOUD COVER WOULD ALLOW FOR HIGHS TO REACH THE
MID 70S).

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
THE UPPER LOW PULLS FARTHER AWAY FROM THE COAST TONIGHT. RIDGE
BUILDING WILL OCCUR ALONG THE EASTERN SEABOARD. CONDITIONS WILL BE
FAVORABLE FOR RADIATIONAL FOG TO DEVELOP OVER THE LEHIGH VALLEY AND
WESTERN SUBURBS OF PHILLY WHERE THE SFC-925 MB RIDGE AXIS IS
FORECAST TO BE POSITIONED OVERHEAD. DOWNSTREAM OF THIS LOW-LEVEL
RIDGE AXIS, MARINE LAYER WILL REMAIN ESTABLISHED UNDER LIGHT
EASTERLY FLOW. ACCORDINGLY, COASTAL LOCATIONS HAVE THE BEST CHANCE
OF SEEING STRATUS RETURN LATE TONIGHT.

FORECAST MIN TEMPS RANGE FROM THE UPPER 40S IN HIGHER ELEVATIONS OF
NORTHWEST NJ/NORTHEAST PA TO NEAR 60S ALONG THE NJ AND DE COAST.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGH PRES OVER ERN CANADA WILL RIDGE DOWN WWD ON FRI AND THIS
FEATURE COUPLED WITH LOW PRES OVER THE OPEN ATLC WILL KEEP ELY
FLOW OVER THE REGION. AS THIS TAKES PLACE, A STRONG AREA OF LOW
PRESSURE WILL BE DEVELOPING NR THE GRTLKS AND MOVG INTO ONTARIO.

THE MDLS STILL DIFFER A BIT IN THE DETAILS OF THE EVOLUTION OF THE
LOW WITH ITS ULTIMATE PLACEMENT AND STRENGTH, BUT AGREE ON THE OVERALL
LARGE-SCALE PATTERN.

THE POTENT CDFNT ASSOCD WITH THIS LOW WILL EXTEND FAR S FROM THIS
LOW AND WILL WORK ITS WAY FROM W TO E FROM FRI NIGHT INTO SAT.

FRI DURG THE DAY SHUD BE DRY WITH PRECIP STILL TO THE W. DURG THE
EVE HOURS PRECIP WILL BEGIN TO MOVE IN FROM THE W AND BY DAYBREAK
SAT PRECIP CHCS WILL EXIST EVERYWHERE, WITH THE BEST CHCS FROM THE
I-95 CORRIDOR N AND W.

THERE IS VERY GOOD DYNAMICS WITH THIS FRONT AND NEG TILTED TROF AND
THE GLFMEX IS OPEN SO THE THREAT OF HVY RAIN IS THERE. HOWEVER,
ANTECEDENT CONDS HAVE BEEN DRY.

DURG THE MRNG HOURS OF SAT SEEMS TO BE THE BEST SHOT OF RAIN FOR
MOST OF US, WITH THE CFP LATE MRNG ERLY AFTN DEPENDING ON
LOCATION, AND PRECIP COMING TO AND END BEHIND THE FROPA FROM SW TO
NE. THE SECOND HALF OF SAT SHOULD BE BETTER THAN THE FIRST.

THEN SAT NIGHT THRU MON LOOKS DRY AS HIGH PRES BUILDS IN FROM THE
S AND SPREADS NEWD.

STRONG CAA MOVES IN SAT NIGHT BEHIND THE FRONT AND IT WILL BE A
BIT BREEZY. WE WILL HAVE OUR FIRST TRUE TOUCH OF FALL WITH TEMPS
NOT HITTING 60 IN MANY AREAS ON SUN AND ANY WIND MAKING IT FEEL
COOLER.  THE WIND SHUD DECREASE DURG THE DAY.

BEYOND MON, A SERIES OF DISTURBANCES WILL BRING SOME ADDITIONAL
SHOTS OF PRECIP THRU MIDWEEK WITH THE MDLS DIFFERING ON THE S/WV
DETAILS WHICH ARE NEARLY IMPOSSIBLE TO RESOLVE AT THIS TIME SCALE.
DID NOT MAKE ANY CHANGES TO THE EXTENDD BEYOND MON NIGHT AS THE
ECMWF WAS DELAYED IN ITS ARRIVAL, AND COULD NOT ANALYZE IT IN TIME
FOR THE FCST ISSUANCE.

TEMPS WILL START OUT NR NRML AND END NR NRML AFTER A SIGNIFICANT
DROP WITH THE CFP OVER THE WKND.

&&

.AVIATION /13Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

CIGS AT MOST TERMINALS AROUND 2-3 KFT SHOULD SLOWLY IMPROVE TO
VFR BETWEEN 14-17Z ALTHOUGH MVFR MAY CONTINUE WELL INTO THE AFTN
AT ACY WHERE MARINE LAYER IS MOST ESTABLISHED. N-NE WINDS AROUND 5
KT AT SUNRISE WILL INCREASE TO AROUND 10 KT THIS AFTN.

VFR EXPECTED THIS EVE. THERE IS A POTENTIAL FOR FOG AND LOW CLOUDS
TO DEVELOP AGAIN BETWEEN 06Z-12Z FRIDAY. FOR THE 12Z TAFS, KEPT
FLIGHT RESTRICTIONS ABOVE IFR FOR NOW AT KPHL SINCE THE END OF THE
30-HR FORECAST COVERS THIS TIME WINDOW.


OUTLOOK...
FRI...MOSTLY VFR. HIGH CONFIDENCE.

FRI NIGHT...INCREASING RAIN CHANCES FROM W TO E AND MVFR/IFR IN
PERIODS OF RAIN, SOME OF IT HEAVY. E TO SE WIND. MDT TO HIGH
CONFIDENCE.

SAT...MVFR/IFR EARLY IN RAIN, SOME OF IT HEAVY, THEN BECOMING VFR
WITH RAIN ENDING FROM SW TO NE. CFP AND WSHFT FROM E TO WNW. MDT
CONFIDENCE.

SUN-MON...VFR. GUSTY NW WIND SUN. HIGH CONFIDENCE.

&&

.MARINE...
THERE WAS A CHANGE TO THE HEADLINE FOR TODAY AND TONIGHT,
CONVERTING THE SMALL CRAFT ADVISORY INTO A SMALL CRAFT ADVISORY FOR
HAZARDOUS SEAS. WINDS WILL BE BELOW 25 KT DURING THIS TIME BUT SEAS
WILL CONTINUE TO BUILD TO 5-6 FT.


OUTLOOK...
FRI...SCA CONDS WILL LIKELY PERSIST ON OUR WATERS THROUGH THE DAY
AND SCA HAS BEEN EXTENDD TO ACCOUNT FOR THIS AS PERSISTENT SELY
FLOW CONTINUES. SEAS WILL CONTINUE TO RUN AROUND 5 FEET. COULD BE
MARGINAL.

SAT...STRONG CFP. WSHFT BACK TOWARDS THE WNW LATER IN THE DAY
BEHIND THE FROPA. A GUSTY WIND IS EXPECTED IN ADVANCE OF THE
FRONT, THEN THERE COULD BE A BRIEF LULL BEFORE THE Y PICK UP AGAIN
BEHIND THE FRONT IN THE CAA. SCA SEEMS LIKELY. GUSTY WINDS ALSO
PSBL IN THE HEAVIER RAIN SHOWERS...MOSTLY IN THE MORNING.

SUN...GUSTY NW WIND WILL CONTINUE BEFORE SUBSIDING DURG THE MRNG.
SEAS SHOULD ALSO DROP BELOW SCA CONDS TO AROUND 3-4 FEET.

MON...NO MARINE HEADLINES ANTICIPATED.

&&

.TIDES/COASTAL FLOODING...
PERSISTENT NORTHEAST WINDS HAVE RESULTED IN POSITIVE TIDAL
DEPARTURES BETWEEN 1-1.5 FT EARLY THIS MORNING. DO NOT EXPECT
ANOMALIES TO INCREASE MUCH TODAY AS THE ONSHORE WINDS SUBSIDE A
BIT. THIS SHOULD RESULT IN TIDES BELOW MINOR FLOODING THRESHOLD
FOR HIGH TIDE THIS AFTERNOON AND TONIGHT.

TIDES ARE EXPECTED TO STAY ABOVE ASTRONOMICAL PREDICTION WITH
ONSHORE FLOW CONTINUING FRIDAY AND SATURDAY. LATEST OFS GUIDANCE
INDICATES TIDAL LEVELS NEAR MINOR COASTAL FLOODING THRESHOLD BY
SATURDAY.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT FRIDAY
     FOR ANZ450>455.

&&

$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/KLEIN
SHORT TERM...KLEIN
LONG TERM...NIERENBERG
AVIATION...KLEIN/NIERENBERG
MARINE...KLEIN/NIERENBERG
TIDES/COASTAL FLOODING...KLEIN





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