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000
FXUS61 KPHI 172331
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
731 PM EDT FRI MAY 17 2013

.SYNOPSIS...
HIGH PRESSURE OVER THE EASTERN GREAT LAKES WILL STRENGTHEN TO COASTAL
NEW ENGLAND THIS WEEKEND. THEREAFTER...A WARM FRONT IN NORTH CAROLINA
WILL EDGE NORTHEAST THROUGH THE MID ATLANTIC STATES ON TUESDAY.
THE FRONT WILL PROBABLY BE OSCILLATING NORTH AND SOUTH IN THE MID
ATLANTIC STATES DURING THE MIDDLE AND END OF NEXT WEEK BEFORE PUSHING
OFFSHORE AS A COLD FRONT AROUND NEXT FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
FAIR THIS EVENING WITH LIGHT WIND. YOU CAN SEE THE SEA BREEZE BOUNDARY
ON THE COASTAL NJ/DE RADARS PENETRATING INLAND. MEANWHILE HIGH PRESSURE
IN THE EASTERN GREAT LAKES WILL BUILD TO OUR NORTH DURING THE NIGHT
AND WINDS WILL TURN LIGHT E OR NE MOST EVERYWHERE DURING THE
NIGHT. MIDDLE DECK CLOUD CURRENTLY (23Z) ALONG THE MASON DIXON LINE
TO NEAR KMIV IS MODELED TO EXPAND EASTWARD DURING THE LATE EVENING
INTO PHL AND THEN ROLLS ESEWD THROUGH SNJ AND THE DELMARVA
OVERNIGHT WITH ITS W EDGE EDGING NEWD THRU E PA AND NJ.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE MID LEVEL LOW WILL CONTINUE TO MOVE SLOWLY TOWARD THE AREA AND
THE MID LEVEL HIGH WILL CONTINUE TO WEAKEN SLOWLY, BUT THERE ARE
STILL SIGNS OF IT JUST TO OUR WEST BY THE END OF THE DAY. WE ONLY
BRING IN SLIGHT CHANCE TO CHANCE POPS DURING THE COURSE OF THE DAY
SOUTHWEST, AND THAT IS LARGELY IN KEEPING WITH CONTINUITY. WE DO
PUSH THE SLIGHT CHANCE POPS FURTHER NORTH OVER OUR WESTERN ZONES AS
PERHAPS ENERGY MOVING OUT OF THE GREAT LAKES CAN TRIGGER SOMETHING
THERE; OTHERWISE THERE`S SOME WEAK ISENTROPIC LIFT AT I295 TO I300K
TO GO WITH THE GRADUAL INCREASE IN LOW LEVEL MOISTURE. THUNDER DOES
NOT SEEM TO BE A CONCERN THIS FAR NORTHEAST. GIVEN THE EXPECTED
CLOUDINESS AND THE MODEST ONSHORE SURFACE FLOW, WE CONTINUE TO
FORECAST COOLER TEMPERATURES ON SATURDAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST SATURDAY NIGHT AND
PUSHES WELL TO OUR EAST THROUGH EARLY NEXT WEEK. THE FRONTAL
BOUNDARY TO OUR SOUTH WILL REMAIN NEARLY STATIONARY THROUGH SUNDAY,
THEN AS THE HIGH BUILDS TO OUR EAST, THE FRONT SHOULD BEGIN MOVING
BACK NORTHWARD AS A WARM FRONT. THE WARM FRONT SHOULD PASS THROUGH
OUR AREA LATE MONDAY INTO TUESDAY, THEN MAY COMBINE WITH A BACKDOOR
FRONT SINKING SOUTHWARD FROM SOUTHERN CANADA. THIS FRONT MAY WOBBLE
SOMEWHERE NEAR OUR AREA, OR JUST NORTHWARD WEDNESDAY INTO THURSDAY,
BEFORE A COLD FRONT PUSHES THROUGH THE AREA LATE THURSDAY INTO
EARLY FRIDAY.

SUNDAY LOOKS TO BE THE COOLEST DAY WITH THE ONSHORE FLOW EXPECTED
WITH HIGH PRESSURE TO OUR NORTHEAST. HOWEVER, TEMPERATURES WILL
SLOWLY RISE THROUGH MID-WEEK AS THE WARM FRONT MOVES THROUGH THE
AREA, AND THICKNESSES INCREASE. TUESDAY AND WEDNESDAY ARE EXPECTED
TO BE THE WARMEST DAYS IN THE FORECAST, THEN COOLING TEMPERATURES
TOWARD LATE WEEK.

THE EXTENDED PERIOD HAS THE POTENTIAL TO BE RATHER UNSETTLED WITH
THE FRONTAL BOUNDARIES MEANDERING THEIR WAY BACK AND FORTH ACROSS
THE AREA AND THE LIKELIHOOD OF SEVERAL SHORT WAVES/VORT MAXES
TRAVERSING THE AREA AS WELL. WITH THE UNCERTAINTY OF THE TIMING OF
EACH EVENT, WE WILL KEEP A CHANCE OF PRECIPITATION IN THE FORECAST
EACH DAY WITH THE GREATEST PROBABILITIES TIED TO THE POSSIBLE
FRONTAL PASSAGES AND VORT MAXES CURRENTLY FORECAST. THUNDERSTORMS
ARE POSSIBLE EACH DAY FROM MONDAY THROUGH THURSDAY AS THERE IS
INSTABILITY BEING FORECAST. SUNDAY WOULD MORE LIKELY BE SHOWERS AS
NO INSTABILITY IS CURRENTLY FORECAST.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TONIGHT...VFR WITH CIGS AOA 7000 FT DEVELOPING DURING THE NIGHT.
LIGHT WIND WHICH AT 23Z IS EAST AT KACY SHOULD BECOME NE OR E
ELSEWHERE DURING THE NIGHT.

SATURDAY...VFR CIGS AOA 7000 FT. MOSTLY E-SE WIND G UNDER 15 KT.


OUTLOOK...
SATURDAY NIGHT...MAINLY VFR WITH LOWERING CLOUDS. A CHANCE OF
SHOWERS.

SUNDAY-MONDAY NIGHT...SUB-VFR CONDITIONS POSSIBLE, ESPECIALLY WITH
ANY SHOWERS, OR THUNDERSTORMS MONDAY.

TUESDAY-WEDNESDAY...GENERALLY VFR, POSSIBLE MVFR CIGS/VSBYS,
ESPECIALLY WITH ANY SHOWERS/THUNDERSTORMS.

&&

.MARINE...
WE ARE FORECASTING SUB-ADVISORY WINDS AND SEAS THROUGH THE DAYLIGHT
PORTION OF SATURDAY. LIGHT WINDS WILL DEVELOP A SOUTHEASTERLY
COMPONENT OVERNIGHT AND INCREASE A BIT ON SATURDAY, BUT NOT ENOUGH
TO REQUIRE AN ADVISORY. SEAS WILL INCREASE A BIT AS WINDS DO.

OUTLOOK...
AS HIGH PRESSURE CONTINUES BUILD ACROSS THE NORTHEAST SATURDAY NIGHT
AND OFFSHORE SUNDAY INTO MONDAY, WINDS MAY APPROACH SMALL CRAFT
LEVELS AS THE PRESSURE GRADIENT TIGHTENS. ALSO, SEAS COULD APPROACH
5 TO 6 FEET SUNDAY INTO MONDAY AS A STEADY SOUTHEAST FLOW DEVELOPS.
ALTHOUGH WINDS MAY NOT REACH ADVISORY LEVELS AS WE GO INTO TUESDAY
AND WEDNESDAY AS THE PRESSURE GRADIENT WEAKENS, WINDS COULD STILL
GUST NEAR 20 KNOTS, AND SEAS MAY REMAIN NEAR 5 TO 6 FEET.

&&

.RIP CURRENTS...
OUR FIRST RIP CURRENT FORECAST OF THE SEASON SHOULD POST THIS EVENING
AROUND 9 PM AND WE ARE PROJECTING A LOW RISK FOR TOMORROW-SATURDAY 5/18.

SAFE BOATING AWARENESS WEEK BEGINS TOMORROW-SATURDAY 5/18 AND ENDS
THE 24TH. RIP CURRENT AWARENESS WEEK IS JUNE 2-8. THERE WILL BE
DAILY PNS`S AND ASSOCIATED PSA`S FOR NWR EVERY DAY FOR BOTH AWARENESS
WEEKS.

WATER TEMPS CURRENTLY APPEAR TO BE SLIGHTLY ABOVE NORMAL.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...DRAG/ROBERTSON 730
NEAR TERM...DELISI/DRAG 730
SHORT TERM...DELISI
LONG TERM...ROBERTSON
AVIATION...DRAG/ROBERTSON 730
MARINE...DELISI/DRAG/ROBERTSON
RIP CURRENTS...730