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000
FXUS61 KPHI 171322
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
922 AM 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/...
12Z SOUNDINGS SUPPORT FORECAST MAX TEMPS FOR TODAY. THE 3K LEVEL
STRATOCU NOT SHOWING UP WELL IN EITHER THE WRF-NMMB OR GFS MASS
FIELDS, ADJUSTMENT MORE ON NOWCASTING. THE TREND WITH BOTH IS FOR
MIXING, DRYING AS THE DAYTIME HOURS PROGRESS, SO WE BLENDED THAT
THOUGHT INTO CONTINUITY.

OTHERWISE...THIS DAY SHOULD BE LOADED WITH SUNSHINE OVER THE
INTERIOR WITH ONLY THIN CIRRUS AT TIMES. WE ARE MONITORING PATCHES
OF 3000 SCTVBKN CLOUDS NJ COAST AT 10Z MOVING WSWWD. THESE CLOUDS
MAY BE A SIGNIFICANT FACTOR ALONG THE NJ COAST AND/OR DE COAST
TODAY AS BOUNDARY LAYER MOISTURE SLOWLY INCREASES WITH CONSTANT
ONSHORE FLOW.

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

TODAY...VFR WITH SOME THIN CIRRUS AT TIMES THEN 3500-4000 FT MIDDAY.
MEANWHILE 3000 SCTVBKN DEVELOPING ALONG THE SRN NJ AND DE COAST MAY
BE PREDOMINANT JUST SOUTH OF KACY. CONFIDENCE ON CEILINGS A BIT
BELOW AVG. WIND E-NE WITH GUSTS 15-20 KT BETWEEN 15-21Z.

TONIGHT...PROBABLY VFR TO START BUT MVFR CIGS MAY DEVELOP LATE OR
POSSIBLE EVEN SPOTTY IFR FOG...ESPECIALLY NJ. LIGHT WIND.
CONFIDENCE ON CIGS/VSBY BELOW AVG.

OUTLOOK... FRIDAY-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...DRAG/ROBERTSON
MARINE...DRAG/ROBERTSON