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Area Forecast Discussion
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000
FXUS61 KPHI 171700
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
100 PM EDT THU APR 17 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OUT OF NEW ENGLAND AND ACROSS THE CANADIAN 
MARITIMES BUT STILL EXTEND ACROSS THE EASTERN SEABOARD THROUGH EARLY 
FRIDAY. A FRONTAL BOUNDARY WILL MOVE ACROSS THE AREA FRIDAY NIGHT 
INTO SATURDAY MORNING, BEFORE HIGH PRESSURE REESTABLISHES ITSELF 
ACROSS EASTERN CANADA AND BUILDS SOUTHWARD ALONG THE EASTERN SEABOARD
SUNDAY INTO MONDAY. ANOTHER FRONTAL BOUNDARY IS EXPECTED TO AFFECT
THE AREA NEXT TUESDAY, FOLLOWED BY HIGH PRESSURE FOR THE MIDDLE OF
NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NEXT ESTF UPDATE MAINLY FOR AN UPWARD A SKY COVER ADJUSTMENT EAST. WE
FOUND THAT THE RAP IS HANDLING THE 925MB MOISTURE THE BEST. WRF-
NMMB FCST SOUNDINGS ALSO LOOK BETTER THAN THE SOME OF THE PLAN
VIEW MODEL MASS FIELDS. THEY BOTH SHOW SOME DRYING WITH MIXING
LATER IN THE AFTERNOON BEFORE PREDICTED CLOUDS ROLL IN AT NIGHT.
TEMPS IRONICALLY ARE RUNNING TOO LOW VS PREDICTIONS IN SUNNIER
LOCALES FAR NORTH. OVERALL THOUGH NO BIG ADJUSTMENTS MADE THERE.
12Z SOUNDINGS SUPPORT FORECAST MAX TEMPS FOR TODAY.  

OTHERWISE...THIS DAY SHOULD BE LOADED WITH SUNSHINE OVER THE
INTERIOR WITH ONLY THIN CIRRUS AT TIMES.  

WINDS WILL BE E-NE GUSTING 15 TO 20 MPH AT TIMES.  

THE FCST BASIS WAS A 50 50 BLEND 00Z/17 NCEP MOS GUIDANCE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
TONIGHTS FCST WAS ALSO A 50 50 BLEND OF THE 00Z/17 NCEP MOS GUIDANCE.
THAT IN MIND...THE FCST TEMPS ARE GENERALLY FREEZING OR JUST ABOVE.
COLLABORATING THE UNCERTAINTY REGARDING A FREEZE OR A FROST...HAVE
BLENDED THE EARLY FRIDAY MORNING HEADLINE WITH OUR NEIGHBORS. HERE
IN THE MOUNT HOLLY AREA...THINK ODDS FAVOR SLIGHTLY WARMER TEMPS
TONIGHT THAN WHAT OCCURRED THIS THURSDAY MORNING AND SO A FROST APPEARS
MORE LIKELY FROM MY VIEW IN OUR AREA...RATHER THAN A FREEZE BUT
ITS POSSIBLE THE GUIDANCE IS 2 DEGREES TOO WARM?

OTHERWISE THE ONSHORE WIND WILL BE DIMINISHING AND BECOME LIGHT.
ITS POSSIBLE THAT LOW CLOUDS WILL FORM OR HAVE ALREADY FORMED AND
LOCKED INTO PORTIONS OF THE COAST THIS EVENING AND THEN DEVELOP
NWD AS THE BOUNDARY LAYER COOLS....ESPECIALLY CENTRAL NJ. PATCHY
FOG IS ALSO POSSIBLE LATE TONIGHT BUT NOT CURRENTLY IN THE GRIDS.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
THE HIGH PRESSURE THAT HAS BEEN EXTENDING SOUTHWARD ACROSS THE EAST 
COAST FROM CANADA WILL BEGIN PULLING OUT OF THE AREA DURING THE DAY 
FRIDAY. AS THIS HAPPENS, OUR AREA WILL BE IN BETWEEN TWO FEATURES 
LATE FRIDAY INTO FRIDAY NIGHT; ONE BEING AN AREA OF LOW PRESSURE TO 
OUR SOUTH OFF THE SOUTHEAST COAST AND THE OTHER AN APPROACHING COLD 
FRONT. WITH THE PERSISTENT NORTHEAST FLOW ACROSS THE AREA, WE EXPECT 
A FAIR AMOUNT OF CLOUD COVER FRIDAY INTO FRIDAY NIGHT. THIS SHOULD
HELP KEEP TEMPERATURES COOL THROUGH THE DAY FRIDAY, SO WE REMAIN
BELOW NORMAL. THE SYSTEM TO OUR SOUTH IS EXPECTED TO REMAIN FAR
ENOUGH TO OUR SOUTH TO PREVENT WIDESPREAD PRECIPITATION TO AFFECT
THE AREA. HOWEVER, THERE REMAINS A SLIGHT CHANCE SOME LIGHT RAIN
ON THE VERY FAR NORTHERN EDGE COULD EXTEND ACROSS OUR SOUTHEASTERN
AREAS, SO WE WILL KEEP SLIGHT CHANCE POPS ACROSS OUR SOUTHEASTERN
ZONES. SOUNDINGS INDICATE THAT THE VERTICAL MOISTURE IS RATHER
SHALLOW, SO IT MAY BE MORE DRIZZLE, SO WE WILL INCLUDE CHANCE
DRIZZLE WITH THE RAIN IN THE FORECAST LATE FRIDAY INTO FRIDAY
NIGHT. THE AFOREMENTIONED COLD FRONT IS EXPECTED TO MOVE THROUGH
THE AREA OVERNIGHT FRIDAY INTO SATURDAY MORNING. ALL GUIDANCE
INDICATES THE PRECIPITATION DRYING OUT AS IT APPROACHES OUR AREA,
SO WE HAVE REMOVED POPS FOR THE REMAINDER OF THE AREA AS WE NOW
EXPECT A DRY FRONTAL PASSAGE.

WE EXPECT DRY WEATHER TO BUILD IN ACROSS THE AREA SATURDAY BEHIND 
THE FRONTAL BOUNDARY AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD OUT 
OF CANADA. THE HIGH SHOULD SUPPRESS THE LOW TO OUR SOUTH BY SATURDAY 
SO THAT IT WOULDN'T HAVE AN EFFECT ON OUR AREA ANYMORE. THIS HIGH 
WILL REESTABLISH ITSELF ACROSS EASTERN CANADA AND BUILDS SOUTHWARD 
ALONG THE EASTERN SEABOARD AGAIN INTO SUNDAY AND MONDAY. THIS WILL 
CONTINUE TO PROVIDE DRY WEATHER OVER THE WEEKEND INTO MONDAY OF NEXT 
WEEK. WITH RIDGING ALOFT TAKING PLACE, TEMPERATURES WILL RETURN 
CLOSER TO NORMAL OVER THE WEEKEND INTO EARLY NEXT WEEK.

ON TUESDAY, A COLD FRONT IS FORECAST TO APPROACH THE AREA FROM THE 
WEST. AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP AND STRENGTHEN 
ALONG THE BOUNDARY AS IT MOVES ACROSS THE AREA LATE TUESDAY INTO 
TUESDAY NIGHT. TUESDAY INTO TUESDAY NIGHT LOOKS TO BE THE NEXT 
CHANCE OF PRECIPITATION ACROSS THE AREA. THEREFORE WE HAVE CHANCE 
POPS ACROSS THE AREA DURING THIS TIME PERIOD.

THIS LOW IS EXPECTED TO SLOWLY PULL TO OUR NORTHEAST THROUGH 
WEDNESDAY AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD OUT OF CANADA 
ONCE AGAIN. WEDNESDAY IS EXPECTED TO BE DRY, BUT SHOULD BE QUITE 
GUSTY WITH THE TIGHTENING PRESSURE GRADIENT.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

WITH 18Z TAFS MVFR CONDITIONS FORECAST TO OCCUR AT ALL OF THE TAF
SITES TONIGHT AND FRIDAY MORNING, ALTHOUGH CONFIDENCE IS
PROGRESSIVELY LOWER THE FARTHER WEST OUR TAF SITES ARE.

FOR THE REST OF THIS AFTERNOON INTO EARLY THIS EVENING A VFR STRATOCU
CIG IS EXPECTED TO CONTINUE TO MOVE WEST AND BE BATTLED BY SOME
MIXING AND DRY AIR. FROM KPHL AREA TERMINALS EASTWARD WE ARE
EXPECTING A VFR CIG AT TIMES, ALTHOUGH KACY MIGHT BECOME MVFR. FARTHER
WEST NO CIG EXPECTED.

EAST WINDS WILL AVERAGE AROUND 10 KTS WITH GUSTINESS UP TO AROUND
20 KTS FROM THE KPHL AREA TERMINALS EASTWARD.

REST OF EVENING AND OVERNIGHT, PREDICTING A MVFR CIG TO OVERSPREAD
ALL THE TERMINALS ARRIVING AT KABE AND KRDG AFTER MIDNIGHT. WINDS
SHOULD BECOME LIGHTER FROM THE EAST.

ON FRIDAY MORNING, THE MVFR CIG IS EXPECTED TO DISSIPATE WITH A
CIRRUS DECK ABOVE IT. SYNOPTIC SCALE WINDS OVERALL SHOULD BE
LIGHTER (GENERALLY AN EASTWARD COMPONENT) THAN TODAY AND A SEA
BREEZE FRONT MAY FORM DURING THE AFTERNOON.
 
OUTLOOK...
FRIDAY AFTERNOON-FRIDAY NIGHT...MVFR CIGS POSSIBLE, ESPECIALLY
CLOSER TO THE COAST.

SATURDAY-MONDAY...MOSTLY VFR. GUSTY N-NW WINDS 15-20 KNOTS SATURDAY.

&&

.MARINE...
SCA CONTINUES ATLC WATERS WITH SEAS ALREADY 5 FT AND WINDS/SEAS TO
BUILD A LITTLE TODAY BEFORE SLOWLY SUBSIDING LATER TONIGHT.

ADDED LOWER DE BAY TO THE SCA PER EXPECTED WIND IMPACT AT THE BAY
ENTRANCE.

OUTLOOK...
FRIDAY-FRIDAY NIGHT...SEAS LIKELY TO REMAIN 5 FEET OR GREATER ON THE 
OCEAN THROUGH EARLY FRIDAY NIGHT, THEN BEGIN TO SUBSIDE.

SATURDAY...SUB-SMALL CRAFT ADVISORY CRITERIA EXPECTED.

SATURDAY NIGHT-SUNDAY...WINDS AND SEAS INCREASING TO SMALL CRAFT 
ADVISORY CRITERIA OVERNIGHT SATURDAY AND CONTINUE INTO SUNDAY, 
ESPECIALLY ON OCEAN.

SUNDAY NIGHT-MONDAY...A RETURN TO SUB-SMALL CRAFT ADVISORY CRITERIA 
EXPECTED SUNDAY NIGHT.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR 
     PAZ060-101>103-106.
NJ...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR 
     NJZ012-013-015-017>022-027.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR ANZ450>455.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ431.

&&

$$
SYNOPSIS...ROBERTSON
NEAR TERM...DRAG/GIGI
SHORT TERM...DRAG
LONG TERM...ROBERTSON
AVIATION...GIGI/ROBERTSON
MARINE...DRAG/ROBERTSON






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