Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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FXUS61 KPHI 180434
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1234 AM EDT SAT APR 18 2015

.SYNOPSIS...
A WEAK SURFACE TROUGH WILL MOVE TO OUR SOUTHEAST OVERNIGHT WITH A
COLD FRONT CROSSING THE REGION SATURDAY AFTERNOON. WEAK HIGH
PRESSURE WILL NOSE DOWN FROM THE NORTH ON SUNDAY. A WARM FRONT
WILL PUSH NORTHWARD INTO OUR REGION ON MONDAY, FOLLOWED BY A COLD
FRONTAL PASSAGE MONDAY NIGHT. ANOTHER FRONTAL PASSAGE IS EXPECTED
LATE WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A SURFACE TROUGH EXTENDED ACROSS SOUTHERN NEW JERSEY AND THE
UPPER DELMARVA AROUND MIDNIGHT. THE FEATURE WAS GETTING MORE
DIFFICULT TO IDENTIFY AS WIND SPEEDS CONTINUED TO DIMINISH.
HOWEVER, THERE WAS ENOUGH OF A DIFFERENCE IN DEW POINT
TEMPERATURES TO HELP LOCATE THE TROUGH. THE SURFACE TROUGH SHOULD
MOVE TO THE SOUTHEAST AND OFF THE COAST BY DAYBREAK.

THERE WERE ISOLATED SHOWERS OFF CAPE MAY COUNTY AROUND MIDNIGHT
AND SCATTERED SHOWERS IN SOUTHERN DELAWARE. THE PRECIPITATION WILL
CONTINUE TO DRIFT EASTWARD AND WHATEVER REMAINS OF IT SHOULD BE
TO THE EAST OF OUR COASTAL WATERS BY ABOUT 300 AM.

TEMPERATURES WERE MAINLY IN THE 50S IN EASTERN PENNSYLVANIA AND
NORTHERN NEW JERSEY, AND IN THE 60S FROM PHILADELPHIA EAST AND
SOUTHWARD AROUND MIDNIGHT. THE WIND IS FORECAST TO REMAIN LIGHT
AND THE SKY IS EXPECTED TO CONTINUE CLEARING. AS A RESULT
TEMPERATURES SHOULD FALL INTO THE UPPER 40S AND LOWER 50S IN MUCH
OF OUR REGION BY DAYBREAK. PATCHY LIGHT FOG REMAINS POSSIBLE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SUNDAY/...
THE FORECAST AREA WILL BE SITUATED JUST TO THE S OF THE FAST W TO
NW FLOW ALOFT THAT RESIDES TOWARD THE BASE OF AN UPPER TROUGH.
THIS UPPER TROUGH IS EXPECTED TO DIG E-SEWD THRU NEW ENGLAND IN
THE AFTERNOON. AT THE SURFACE...HIGH PRESSURE OVER CENTRAL CANADA
WILL RIDGE S AND EWD TOWARD THE OH VALLEY AND MID-ATLANTIC STATES
IN THE MORNING. SURFACE LOW PRESSURE ASSOCIATED WITH THE
AFOREMENTIONED UPPER WAVE WILL TRACK ACROSS NEW ENGLAND IN THE
AFTERNOON. NW FLOW BEHIND THE LOW WILL BE ALLOW ITS COLD FRONT TO
SURGE SEWD ACROSS NE PA AND NW NJ DURING THE MID AFTERNOON AND
LATE AFTERNOON TO EARLY EVENING FARTHER S AND E.

NOT MUCH CHANGE IN THINKING FROM THE PREVIOUS SHIFT WITH REGARDS
TO LEANING ON THE WARM SIDE OF TEMP GUIDANCE IN THIS SETUP. WE
WILL BE POSITIONED IN THE PRE-FRONTAL WARM SECTOR WHERE DEEP
MIXING PROFILES WILL DEVELOP AS A RESULT OF STRONG DAYTIME HEATING
AND DOWNSLOPING FLOW. HIGHS IN THE MID TO UPPER 70S WILL BE COMMON
EXCEPT COOLER IN THE POCONOS AND ALONG THE COAST. WOULD NOT BE
SURPRISED TO SEE A FEW WARMER SPOTS TO REACH 80F.

WLY WINDS AROUND 10 TO 15 MPH WILL SHIFT OUT OF THE NW AND BECOME
GUSTY LATE IN THE DAY AFTER THE COLD FRONT MOVES THRU.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
SATURDAY NIGHT THROUGH SUNDAY...FOR THE MOST PART THIS PERIOD
LOOKS TO BE FAIRLY QUIET. HIGH PRESSURE WILL NOSE DOWN FROM THE
NORTH BRINGING IN SOME COOLER AIR FOR SATURDAY NIGHT THROUGH
SUNDAY. DRY CONDITIONS WILL PREVAIL THROUGH MOST OF SUNDAY WITH
INCREASING CLOUDINESS AND INCREASING MOISTURE IN ADVANCE OF AN
APPROACHING WARM FRONT. RAIN SHOWERS WILL START PUSH INTO THE AREA
LATE SUNDAY.

MONDAY THROUGH TUESDAY...MOISTURE WILL CONTINUE TO INCREASE AS
THE WARM FRONT PROGRESSES NORTHWARD INTO AND THROUGH OUR AREA.
PRECIPITABLE WATER VALUES WILL RISE UP NEAR 1.5 INCHES ACROSS THE
REGION WHICH WILL CAUSE RAIN TO BECOME HEAVY AT TIMES. WE HAVE
ADDED SOME THUNDER INTO THE FORECAST FOR MONDAY AFTERNOON/EVENING
AS SOME INSTABILITY OCCURS WHILE WE ARE IN THE WARM SECTOR, BEHIND
THE WARM FRONT AND BEFORE THE COLD FRONT PUSHES THROUGH THE
REGION. CHANCES FOR THUNDER LOOK BETTER AS YOU HEAD TO THE SOUTH
AND EAST OF PHL WITH WEAKER INSTABILITY TO THE NORTH AND WEST. WE
HAVE INCLUDED A CHANCE OF THUNDER FOR THOSE AREAS TO THE SOUTH AND
EAST OF PHL AND CONTINUE TO LEAVE OUT OF OTHER AREAS AT THIS TIME.
GUSTY SOUTHEASTERLY WINDS WILL ALSO OCCUR, ESPECIALLY ALONG THE
COASTAL AREAS, A STRONG LOW LEVEL JET CROSSES THE REGION ON
MONDAY. RAIN, WITH RUMBLES OF THUNDER TO THE SOUTH, WILL GRADUALLY
TAPER OFF TO THE NORTH AND EAST THROUGH THE EVENING AND INTO THE
OVERNIGHT HOURS. THE COLD FRONT ARRIVES OVERNIGHT AND SHOULD BE
LEAVING THE AREA TUESDAY MORNING. SHOWERS WILL END AS THE FRONT
PASSES TO THE EAST BUT WITH A PERSISTENT UPPER LEVEL TROUGH
NEARBY, SHOWERS MAY CONTINUE ACROSS THE NORTHERN AREAS THROUGH THE
AFTERNOON.

WEDNESDAY THROUGH FRIDAY....A PERSISTENT UPPER LEVEL TROUGH WILL
SPIN OVER THE GREAT LAKES AREA WITH A GRADUAL PUSH TO EAST THROUGH
THE WEEK. SEVERAL SHORTWAVES EMBEDDED IN THE UPPER LEVEL FLOW WILL
ROTATE THROUGH OUR AREA AND PUSH A COLD FRONT THROUGH OUR AREA
LATE WEDNESDAY INTO THURSDAY. SHOWERS WILL REMAIN POSSIBLE,
ESPECIALLY ACROSS THE NORTHERN AREAS. AS THE FRONT DROPS TO THE
SOUTH OF THE AREA, IT MIGHT STALL AND WEAK WAVE MAY MOVE ALONG IT
AND THROUGH THE SOUTHERN AREAS ON THURSDAY. SOME LIGHT SHOWERS MAY
OCCUR AS A RESULT OF THIS FEATURE. THE MODEL SOLUTIONS DIVERGE
BEYOND WEDNESDAY AND PLENTY OF UNCERTAINTY AS TO WHICH FEATURES
WILL IMPACT OUR AREA THROUGH THE END OF THE WEEK.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY, AND SURROUNDING AREAS.

PREDOMINATELY VFR EXPECTED TONIGHT AS SKIES CLEAR OVNGT. HOWEVER,
PATCHY FOG COULD DEVELOP IN THE TYPICAL FOG-PRONE TERMINALS EARLY
IN THE MORNING. A TEMPO GROUP FOR MVFR VSBY RESTRICTIONS WAS
INCLUDED AT THOSE TAF SITES. WINDS WILL BECOME LIGHT AND VARIABLE
TONIGHT.

VFR ON SATURDAY. LIGHT WINDS IN THE MORNING WILL INCREASE IN THE
AFTN TO AROUND 10 KT. WIND GUSTS TO 20 KT POSSIBLE LATE IN THE DAY
WITH A COLD FRONT PASSAGE.

OUTLOOK...

SATURDAY NIGHT THROUGH SUNDAY...MAINLY VFR CONDITIONS ARE
EXPECTED. INCREASING CLOUDINESS THROUGH SUNDAY WITH SOME SHOWERS
DEVELOPING LATE. NORTHEAST TO EAST WINDS AROUND 10 KNOTS.

MONDAY...MVFR/IFR CONDITIONS WITH PERIODS OF RAIN. LOW LEVEL WIND
SHEAR IS POSSIBLE FOR A TIME ON MONDAY. SOUTHEAST WINDS 10 TO 15
KNOTS EXPECTED.

TUESDAY...MVFR/IFR CONDITIONS EARLY WITH IMPROVING CONDITIONS AS
RAIN EXITS TO THE NORTH AND EAST OF THE TERMINALS. HOWEVER, SOME
SHOWERS REMAIN POSSIBLE THROUGH THE DAY. LIGHT WESTERLY WINDS.

WEDNESDAY...MAINLY VFR CONDITIONS EXPECTED. SHOWERS ARE POSSIBLE,
MAINLY FROM KPHL AND TO THE NORTH AND WEST. LIGHT WESTERLY WINDS.

&&

.MARINE...
A LIGHT AND VARIABLE WIND IS EXPECTED OVERNIGHT INTO SATURDAY.
WAVE HEIGHTS ON OUR OCEAN WATERS WILL RANGE FROM 2 TO 3 FEET.

OUTLOOK...

SATURDAY NIGHT AND SUNDAY...SUB-ADVISORY CONDITIONS ARE EXPECTED.
SOME GUSTS NEAR 25 KNOTS LATE SUNDAY.

MONDAY THROUGH TUESDAY...WINDS WILL INCREASE AS A RESULT OF A
STRENGTHENING LOW LEVEL JET MOVING ACROSS THE REGION. WITH MORE
STABLE AIR AT THE SURFACE, IT MAY BE DIFFICULT TO MIX DOWN SOME OF
THE STRONGER WINDS JUST ABOVE THE SURFACE. HOWEVER, GUSTY
SOUTHEASTERLY WINDS WILL OCCUR AT THE SURFACE AND WE MAY SEE SOME
GUSTS AROUND 30 KNOTS ON MONDAY. AS THE JET MOVES THROUGH, ALONG
WITH A FRONTAL SYSTEM, WINDS WILL TURN MORE SOUTHERLY AND THEN
BECOME MORE WESTERLY THROUGH TUESDAY, WEAKENING THROUGH THAT TIME.
SEAS WILL BUILD AND EXCEED 5 FEET ON THE OCEAN AND MAY BE SLOW TO
SUBSIDE ON TUESDAY. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED
FOR MONDAY AND TUESDAY.

WEDNESDAY...SUB-ADVISORY CONDITIONS ARE EXPECTED ON THE AREA
WATERS. WINDS WILL BE OUT OF THE WEST AROUND 10 TO 15 KNOTS.

&&

.FIRE WEATHER...
AFTER COORDINATION WITH STATE FIRE OFFICIALS THIS AFTERNOON, A
FIRE WEATHER WATCH HAS BEEN ISSUED FOR SATURDAY LATE AFTERNOON AND
EARLY EVENING THAT INCLUDES NE PA AND ADJACENT PORTIONS OF NW AND
C NJ. THESE NRN AREAS WILL SEE GUSTY NW WINDS DEVELOP LATE IN THE
AFTN BEHIND A COLD FRONT. FARTHER SOUTH TOWARD SE PA AND S NJ,
THERE IS MORE UNCERTAINTY THAT THE FRONT WILL MAKE IT THAT FAR
SOUTH IN TIME TO ALLOW THE GUSTY WINDS TO DEVELOP SINCE IT WILL
OCCUR AFTER PEAK DAYTIME MIXING. IF THE ARRIVAL OF THE FRONT
SPEEDS UP, THEN HEADLINES MAY NEED TO BE EXPANDED FARTHER SOUTH.
CONDITIONS WILL BE DRY ACROSS ALL OF THE FORECAST AREA WITH
MINIMUM RH VALUES ARE FORECAST IN THE 20 TO 30 PERCENT RANGE AND
FUEL MOISTURE BELOW 10 PERCENT.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FIRE WEATHER WATCH FROM THIS AFTERNOON THROUGH THIS EVENING
     FOR PAZ054-055-060>062-103-105-106.
NJ...FIRE WEATHER WATCH FROM THIS AFTERNOON THROUGH THIS EVENING
     FOR NJZ001-007>010-012-013-015.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...MEOLA
NEAR TERM...IOVINO
SHORT TERM...KLEIN
LONG TERM...MEOLA
AVIATION...AMC/MEOLA
MARINE...KLEIN/MEOLA
FIRE WEATHER...KLEIN


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