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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 181710
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
110 PM EDT FRI APR 18 2014

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO EXTEND ACROSS THE EASTERN SEABOARD
THROUGH THIS AFTERNOON. THE HIGH WILL RETREAT AS A WEAKENING
FRONTAL BOUNDARY MOVES ACROSS THE AREA TONIGHT INTO SATURDAY
MORNING. HIGH PRESSURE REESTABLISHES ITSELF ACROSS EASTERN CANADA
OVER THE WEEKEND AND BUILDS SOUTHWARD ALONG THE EASTERN SEABOARD
SUNDAY INTO MONDAY. ANOTHER FRONTAL BOUNDARY IS EXPECTED TO AFFECT
THE AREA NEXT TUESDAY, FOLLOWED BRIEFLY BY HIGH PRESSURE WEDNESDAY
NIGHT INTO THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST ESTF UPDATE NO BIG CHANGES PLANNED. WE ARE LOSING THE
STRATOCU CIG AND THE CIRRUS OVERALL LOOKS THINNER. WE LOWERED THE
SKY COVERAGE. MAX TEMPS NOT CHANGED MUCH, WE CONTINUE TO BACK END
THEM TOWARD THE END OF AFTERNOON.

TODAY...FCST BASIS IS MOSTLY NAM 3RLY TEMPS AND MAX TEMP DURING THE
DAY AND THE HIGHER OF THE NCEP 3 HRLY MOS DEWPOINTS. 50 50 BLENDED
SFC SUSTAINED WINDS.

CONSIDERABLE HIGH CLOUD DURING MID AND LATE AFTN. E WIND GUST
NEAR 15 MPH WITH THE WIND BECOMING S-SE LATE IN THE DAY. MAX TEMPS
NEAR 5 PM THIS AFTN IN THE INTERIOR AS THE LOW CLOUDS DISSIPATE
DURING THE AFTN AND TEMPS MAY RISE 5 DEGREES BETWEEN 2P AND 5P
VCNTY PHILADELPHIA.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
TONIGHT...FCST BASIS IS A 50 50 BLEND OF THE 00Z/18 NCEP MOS GUIDANCE
WITH THE COLDER OF THE LOW TEMPS NEAR 10Z/SAT.

CONSIDERABLE HIGH CLOUD THIS EVENING WITH CFP SCT-BKN SC NEAR 4000
FT TOWARD DAWN SATURDAY. LIGHT SE-S WIND DURING THE EVENING TURN W
OR NW LATE AT NIGHT.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
WE EXPECT DRY WEATHER TO BUILD IN ACROSS THE AREA SATURDAY BEHIND
THE WEAKENING FRONTAL BOUNDARY THAT WILL CROSS THE AREA EARLY
SATURDAY MORNING AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD OUT OF
CANADA. THE HIGH SHOULD SUPPRESS THE LOW TO OUR SOUTH OFF THE
SOUTHEAST COAST WHICH SHOULD PREVENT ANY PRECIPITATION FROM REACHING
OUR AREA.

THIS HIGH WILL REESTABLISH ITSELF ACROSS EASTERN CANADA AND BUILD
SOUTHWARD ALONG THE EASTERN SEABOARD SUNDAY AND MONDAY. THIS WILL
CONTINUE TO PROVIDE DRY WEATHER OVER THE WEEKEND INTO MONDAY OF NEXT
WEEK. WITH SLIGHT RIDGING ALOFT TAKING PLACE, TEMPERATURES WILL
RETURN CLOSER TO NORMAL OVER THE WEEKEND INTO EARLY NEXT WEEK.
SUNDAY WILL LIKELY BE THE COOLEST DAY WHEN THICKNESSES AND 925 MB
TEMPERATURES ARE AT THEIR LOWEST.

THE HIGH WILL WEAKEN AND RETREAT MONDAY NIGHT AHEAD OF AN
APPROACHING STORM SYSTEM. AN AREA OF LOW PRESSURE IS FORECAST TO
MOVE OUT OF THE GREAT LAKES REGION AND STRENGTHEN AS IT MOVES INTO
NEW ENGLAND TUESDAY INTO TUESDAY NIGHT. AS THIS OCCURS, A COLD
FRONT WILL SWEEP THROUGH THE AREA LATE TUESDAY INTO TUESDAY NIGHT,
WHICH WILL BRING THE NEXT CHANCE OF PRECIPITATION ACROSS THE AREA.
THEREFORE WE MAINTAIN CHANCE POPS ACROSS THE AREA DURING THIS TIME
PERIOD.

THIS LOW IS EXPECTED TO SLOWLY PULL TO OUR NORTHEAST THROUGH
WEDNESDAY AND THURSDAY AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD
OUT OF CANADA ONCE AGAIN. WEDNESDAY AND THURSDAY ARE EXPECTED TO BE
DRY, BUT SHOULD BE QUITE GUSTY WITH THE TIGHTENING PRESSURE
GRADIENT. WINDS COULD EASILY GUST 25-30 MPH, IF NOT HIGHER.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

PREDOMINATELY VFR CONDITIONS WITH THE 18Z TAFS.

FOR THIS AFTERNOON, SOME MVFR CIGS MAY LINGER AT KACY AND COASTAL
AIRPORTS, BUT THE TREND TOWARD DISSIPATION IS CONTINUING. ALL
OTHER TERMINALS AND AIRPORTS, NO CIG IS PREDICTED BELOW CIRRUS
LEVEL. WINDS SHOULD BE MAINLY SOUTHEAST AT LESS THAN 10 KNOTS.

SEA BREEZE FRONT SHOULD FORM ALONG THE COASTAL COUNTIES OF NJ AS
WELL AS NEAR DELAWARE BAY. BUT, THE WESTWARD PROGRESSION LOOKS TO
MELD WITHIN THE GENERAL VEERING SOUTHEAST TO SOUTH SYNOPTIC SCALE
FLOW LATER THIS AFTERNOON.

TONIGHT, A CIRRUS DECK OF CLOUDS EXPECTED WITH GENERALLY LIGHT AND
VARIABLE WINDS. THERE COULD BE A FEW STRATOCU LEVEL CLOUDS CLOSE
TO THE PASSAGE OF THE COLD FRONT. ANY DIRECTION OVERNIGHT IF THERE
IS ANY WILL LIKELY BE SOUTH TO SOUTHWEST. FOG, CONFIDENCE OF IT
OCCURRING TOO LOW TO INCLUDE AT TERMINALS. ALTHOUGH, VERY RURAL
AIRPORTS MIGHT HAVE SOME TOWARD MORNING.

SATURDAY. A COLD FRONTAL PASSAGE EARLY WITH A BRISKER NORTH TO
NORTHWEST WIND EXPECTED WITH PEAK GUSTS NEAR 20 KTS. NOT TOTALLY
CONFIDENT ABOUT GUSTINESS, MAY END UP BEING A SUSTAINED 10 TO 15
KT DAY. ANY SEA BREEZE FRONT WOULD FORM LATE IN THE DAY AND BE
CONFINED CLOSE TO THE IMMEDIATE COAST. CLEAR SKIES PREDICTED.

OUTLOOK...
SATURDAY NIGHT-MONDAY NIGHT...MOSTLY VFR.

TUESDAY...MVFR CONDITIONS POSSIBLE WITH SHOWERS WITH A FRONTAL
PASSAGE.

&&

.MARINE...
SEAS 7 FT AT 44009 AT 5 AM.

GFS WW4 GUIDANCE HAS BEEN TOO LOW BY A FOOT OR 2 ON THE ATLANTIC
WATERS AND SO RAISED THAT GUIDANCE THRU THIS FRIDAY EVENING.

SCA CONTINUES OPEN ATLC WATERS...MAINLY FOR SEAS AND HAVE CONVERTED
THAT SCA HEADLINE TO SCA FOR HAZARDOUS SEAS HERE AT THE 3 AM ISSUANCE.

DE BAY WATERS NO HEADLINE THRU TONIGHT. E-NE WIND G 15 KT AND SEAS
LESS THAN 3 FT TODAY. WINDS AND SEAS DIMINISH/SUBSIDE TONIGHT. THE
WIND TURN S TOWARD SUNSET THEN SHIFTS TO W OR NW TOWARD DAWN SATURDAY.

OUTLOOK...
SATURDAY...SUB-SMALL CRAFT ADVISORY CRITERIA EXPECTED, THOUGH
WINDS MAY GUST NEAR 20 KNOTS.

SATURDAY NIGHT-SUNDAY NIGHT...WINDS AND SEAS INCREASING TO SMALL CRAFT
ADVISORY CRITERIA OVERNIGHT SATURDAY AND CONTINUE INTO SUNDAY. SEAS
MAY REMAIN ELEVATED INTO SUNDAY NIGHT.

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

TUESDAY...FRONTAL PASSAGE EXPECTED WITH NEAR ADVISORY CONDITIONS.

&&

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

&&

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