-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 250813
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
413 AM EDT FRI APR 25 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY AS LOW PRESSURE ADVANCES EAST
THROUGH THE OHIO VALLEY, CROSSING OUR REGION TONIGHT INTO SATURDAY
MORNING. HIGH PRESSURE IS THEN EXPECTED TO INFLUENCE OUR AREA
SATURDAY NIGHT THROUGH MONDAY. THE NEXT LOW PRESSURE SYSTEM LOOKS TO
DEVELOP ACROSS THE PLAINS STATES MONDAY AND IS FORECAST TO BE
SLOW-MOVING, RESULTING IN UNSETTLED WEATHER ACROSS OUR REGION FROM
TUESDAY THROUGH THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL BE OVER THE REGION EARLY BUT MOVE EASTWARD THRU
THE COURSE OF THE DAY.  AS IT DOES, AN AREA OF LOW PRES OVER THE OH
VLY WILL MOVE EWD AS WELL.  CLOUDS WILL INCREASE, THICKEN AND LOWER
AS THE DAY PROGRESSES.  WHILE MOST OF THE DAY LOOKS TO BE DRY, RAIN
WILL DEVELOP FROM W TO E BY LATE AFTN/ERLY EVE.  TEMPS SHOULD END UP
RIGHT AROUND NRML AND IT WILL BE MUCH LESS WINDY THAN IT HAS BEEN
OVER THE LAST FEW DAYS.

BASED ON CURRENT TEMPS AND LONGER DAYLIGHT HOURS, HAVE OPTED TO DROP
THE FREEZE WARNING..FOR ALL BUT SUSSEX AND WARREN COUNTIES.  THERE COULD BE
SOME SPOTS THAT MAKE IT TO FREEZING OR CLOSE, BUT DO NOT EXPECT
WIDESPREAD FREEZING TEMPS ATTM.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
THE AFOREMENTIONED LOW PRES WILL MOVE ACRS THE REGION DURG THE FIRST
PART OF TONIGHT BRINGING RAIN TO THE AREA.  RUMBLES OF THUNDER CAN
NOT BE RULED OUT, ESPECIALLY OVER THE SRN AREAS.  THE LOW AND ITS
ATTENDANT CDFNT WILL MOVE THRU OVERNIGHT AND PRECIP SHUD END FROM SW
TO NE BY DAYBREAK.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
TO START THE LONG TERM, AN AREA OF SURFACE LOW PRESSURE IS FORECAST
TO BE PASSING BY TO OUR NORTHEAST SATURDAY MORNING, WITH MUCH OF THE
SCATTERED/ISOLATED SHOWER ACTIVITY DIMINISHING AT THAT TIME.
HOWEVER, THE PRIMARY UPPER LEVEL TROUGH/CLOSED LOW IS PROGGED TO
DROP SOUTHEAST FROM THE NORTHERN GREAT LAKES INTO NEW YORK STATE
THROUGH THE COURSE OF THE DAYTIME SATURDAY, AND WITH COLDER AIR
PRESENT ALOFT IN THE ATMOSPHERE, MORE SCATTERED SHOWERS WILL BE THE
RESULT. THE GFS/NAM AND ECMWF ALL SHOW SOME VERY MARGINAL
INSTABILITY TO BE PRESENT SATURDAY AFTERNOON TO EARLY EVENING, BUT
WE OPTED NOT TO ADD THUNDER AT THIS TIME AS WHAT MAY OCCUR IS ONLY
SOME LOW-TOPPED CONVECTIVE ACTIVITY. THROUGH THIS TIMEFRAME, WE KEEP
SLIGHT CHANCE TO LOW CHANCE POPS FOR ISOLATED/SCATTERED SHOWERS.

BY LATER SATURDAY NIGHT AND EARLY SUNDAY, THE UPPER LEVEL
TROUGH/CLOSED LOW IS FORECAST TO MOVE EAST AND OFF THE NEW ENGLAND
COAST AS HIGH PRESSURE NOSING DOWN FROM CANADA BEGINS TO INFLUENCE
OUR REGION. WEAK HIGH PRESSURE IS PROGGED TO REMAIN ACROSS THE MID
ATLANTIC THROUGH THE DAYTIME SUNDAY THROUGH MONDAY, AND WE MAINTAIN
A DRY FORECAST THROUGH THIS PERIOD WITH TEMPERATURES OVERALL RUNNING
A FEW DEGREES BELOW LATE APRIL NORMALS.

A MORE ACTIVE AND UNSETTLED PATTERN LOOKS TO TAKE SHAPE THROUGH THE
MIDWEEK PERIOD AS A SLOW-MOVING LOW PRESSURE SYSTEM ORGANIZES ACROSS
THE PLAINS STATES MONDAY AND THEN GRADUALLY PROGRESSES EAST. WE HAVE
KEPT THE MENTION OF SLIGHT CHANCE/LOW CHANCE POPS FOR SHOWERS IN THE
FORECAST FOR LATE MONDAY NIGHT AS MORE OF AN ONSHORE FLOW DEVELOPS
ACROSS OUR REGION. FROM THERE, POPS INCREASE MOSTLY INTO THE HIGH
CHANCE/LOW LIKELY RANGE FOR THE TUESDAY THROUGH THURSDAY TIMEFRAME
AS THE SURFACE AND UPPER LEVEL LOWS ADVANCE INTO THE MISSISSIPPI
VALLEY AND A FEW MID/UPPER SHORTWAVES PASS NEAR OR OVER OUR REGION
BRINGING ROUNDS OF SCATTERED SHOWERS. WHILE SOME EMBEDDED THUNDER IS
POSSIBLE AT TIMES WITH THIS ACTIVITY, WE HAVE NOT INCLUDED THUNDER
AT THIS EXTENDED TIMEFRAME AS THERE IS STILL UNCERTAINTY REGARDING
THE AMOUNT OF INSTABILITY PRESENT AS AN ONSHORE, EASTERLY FLOW LOOKS
TO HOLD ON THROUGH MIDWEEK. WITH CLOUDS AND SHOWERS AROUND, DAYTIME
TEMPERATURES ARE EXPECTED TO RUN WELL BELOW AVERAGE, WITH HIGHS ONLY
IN THE 50S FOR MUCH OF THE REGION, ESPECIALLY TUESDAY AND WEDNESDAY.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

VFR CONDS ARE EXPECTED FOR THE FIRST PORTION OF THE TAF PD WITH HIGH
PRES OVER THE REGION, GRADUALLY MOVG EWD.

THEN CONDS WILL DETERIORATE AS LOW PRES, OVER THE OH VLY MOVES EWD
AND BRINGS RAIN TO THE REGION.  CONDS WILL DROP TO MVFR AND PSBL IFR
BEGINNING LATE THIS AFTN/ERLY THIS EVE FROM W TO E. RAIN SHUD END
FROM SW TO NE DURING THE OVERNIGHT HOURS.

THE WIND WILL BE MUCH LOWER THAN THE LAST 2 DAYS WITH SELY WIND
GUSTS PSBLY AS HIGH AS 15 TO 20 KTS DURG THE DAY.  THE WIND WILL
THEN BECOME LESS THAN 10 KTS THIS EVE AND MAY EVEN BECOME LIGHT AND
VARIABLE FOR A TIME BEFORE SHIFTING TO THE NW AFTER CFP LATE TONIGHT.

OUTLOOK...
SATURDAY...ANY SUB-VFR CONDITIONS IMPROVE BACK TO VFR EARLY SATURDAY
MORNING. SOME SCATTERED SHOWERS ARE POSSIBLE FOR SATURDAY AFTERNOON,
BUT CONDITIONS SHOULD REMAIN MAINLY VFR.

SUNDAY AND MONDAY...MAINLY VFR CONDITIONS WITH WEAK HIGH PRESSURE.
AN ONSHORE FLOW IS EXPECTED TO DEVELOP MONDAY NIGHT WITH SOME MVFR
CEILINGS POSSIBLE INTO EARLY TUESDAY.

TUESDAY...MVFR CEILINGS ANTICIPATED TO DEVELOP WITH AN ONSHORE FLOW.
SOME RAIN IS FORECAST TO OVERSPREAD THE AREA FROM SOUTH TO NORTH,
WITH CONTINUED MVFR CONDITIONS.

&&

.MARINE...
NO MARINE HEADLINES WILL BE CARRIED FOR THE NEAR AND SHORT TERM PDS
WITH HIGH PRES OVER THE AREA MOVG SLOWLY EWD.  BY THE END OF THE
PD...ERLY SAT MRNG, WIND MAY INCREASE AS LOW PRES MOVES THRU THE
REGION AND WE MAY APPROACH SCA CRITERIA.  HOWEVER, CONFIDENCE WAS
NOT HIGH ENOUGH TO ISSUE A AN ADVY ATTM.

OUTLOOK...
SATURDAY...POSSIBLE SCA CONDITIONS MAY BEGIN THE DAY ACROSS THE AREA
WATERS AS LOW PRESSURE PASSES BY TO THE NORTHEAST, BUT IMPROVEMENT
TO SUB-SCA SHOULD BE RELATIVELY QUICK BY SATURDAY AFTERNOON/EVENING.

SUNDAY AND MONDAY...MAINLY SUB-ADVISORY CONDITIONS ARE EXPECTED.

TUESDAY...AN EASTERLY ONSHORE FLOW IS EXPECTED; ALTHOUGH, WIND
GUSTS LOOK TO REMAIN SUB-ADVISORY AT THIS TIME. SEAS, HOWEVER, ARE
EXPECTED TO BUILD FOR THE COASTAL WATERS INTO THE 5 FOOT RANGE.

&&

.FIRE WEATHER...
THERE LOOKS TO BE AN ELEVATED FIRE RISK AGAIN TODAY, THOUGH LESS
THAN YESTERDAY, ESPECIALLY FOR EASTERN PENNSYLVANIA AND NEW JERSEY.
TEMPERATURES WILL BE A FE DEGREES WARMER. BUT THE WIND IS ONLY
EXPECTED TO GUST IN THE 15 TO 20 MPH RANGE FROM LAT THIS MORNING
INTO THE EARLY AFTERNOON.  THE AIRMASS IS STILL VERY DRY AND
RELATIVE HUMIDITY VALUES ARE EXPECTED TO DROP INTO THE 20S FOR A
TIME.  HOWEVER, LOW PRESSURE WIS APPROACHING FROM THE WEST AND BY
LATE AFTERNOON, HUMIDITY VALUES ARE EXPECTED TO INCREASE AND RAIN IS
ANTICIPATED BY LATE AFTN/ERLY EVE.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...FREEZE WARNING UNTIL 8 AM EDT THIS MORNING FOR NJZ001-007.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KLINE
NEAR TERM...NIERENBERG
SHORT TERM...NIERENBERG
LONG TERM...KLINE
AVIATION...KLINE/NIERENBERG
MARINE...KLINE/NIERENBERG
FIRE WEATHER...