FXUS61 KPHI 061536
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1136 AM EDT SAT SEP 6 2008
.SYNOPSIS...
TROPICAL STORM HANNA MOVED ONSHORE OVER NORTHEASTERN SOUTH
CAROLINA EARLY THIS MORNING. THE STORM WILL MOVE NORTHWARD TODAY
CROSSING DELAWARE THIS AFTERNOON AND SOUTHERN NEW JERSEY THIS EVENING
ON ITS WAY TO NEW ENGLAND TONIGHT. WEAK HIGH PRESSURE WILL FOLLOW
LATE SUNDAY AND MONDAY FOLLOWED BY A COLD FRONT ON TUESDAY. HIGH
PRESSURE WILL THEN BUILD OVER THE REGION WEDNESDAY AND THURSDAY
AND OFFSHORE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HEAVY RAINS FROM HANNA ARE NO AFFECTING THE AREA ALTHOUGH THE
CENTER REMAINS TO OUR SOUTH. THE TRACK OF THE STORM CONTINUES TO
BRING THE CENTER THROUGH THE DELMARVA AND SOUTHERN NEW JERSEY THIS
AFTERNOON AND EVENING. THE MAIN CONCERN FROM TROPICAL STORM HANNA
WILL BE FLOODING THROUGHOUT THE REGION. STRONG WINDS ARE ALSO A
THREAT, MAINLY ALONG THE COASTAL WATERS AND THE COASTAL PLAIN, BUT
SOME OF THE STRONG GUSTY WINDS COULD ALSO REACH FARTHER INLAND.
NOW THAT THE RAIN HAS BEGUN, IT WILL LAST THROUGH THE AFTERNOON
AND MOST OF THE EVENING HOURS. WITH THE EXPECTED TRACK, AND VERY
HEAVY RAINS THAT ARE ANTICIPATED, 4 TO 7 INCHES OF RAIN COULD
FALL. THE AREA THAT IS EXPECTED TO SEE THE LARGEST NUMBERS SHOULD
BE ACROSS CENTRAL AND NORTHERN NEW JERSEY SOUTHWESTWARD THROUGH
EAST CENTRAL AND SOUTHEAST PENNSYLVANIA. EVEN THOUGH THE GROUND IS
STARTING OUT RELATIVELY DRY, WHEN THE HEAVY RAINS DO ARRIVE, IT
SHOULD FALL IN A 6 TO 8 HOUR WINDOW. THE COMBINATION OF THE VERY
HEAVY RAINS AND THE RELATIVE SHORT TIME FRAME THAT IT SHOULD FALL,
WOULD MOST LIKELY CAUSE FLOODING, ESPECIALLY ON THE SMALLER
STREAMS AND CREEKS AS WELL AS POOR DRAINAGE AREAS.
NO CHANGES HAVE BEEN MADE TO ANY OF THE THE WARNINGS AND WATCHES.
A TROPICAL STORM WARNING FOR COASTAL SECTIONS...A TROPICAL STORM
WIND WARNING FOR ADJACENT INLAND SECTIONS...A WIND ADVISORY FOR
THE LEHIGH VALLEY AND POCONO AREAS OF PENNSYLVANIA...AND A FLOOD
WATCH FOR THE ENTIRE AREA. SEE THE HLS, FFA, AND NPW FOR
PARTICULARS. ALSO, REFER PLEASE REFER TO THE NATIONAL HURRICANE
CENTER, WWW.NHC.NOAA.GOV, FOR MORE DETAILS ON TROPICAL STORM HANNA.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
HANNA WILL BE DEPARTING AFTER MIDNIGHT AND RAINS WILL BECOME
SHOWERY AND THEN END. THE WINDS WILL ALSO BE ON THE DECREASE LATE
TONIGHT IN THE WAKE OF HANNA. THE CIRCULATION BEHIND HANNA SHOULD
MERGE WITH A WEAKENING COLD FRONT TO THE NORTHWEST AND THIS FRONT
WILL BE PULLED THROUGH THE REGION LATE TONIGHT ALLOWING THE
HUMIDITY TO DECREASE. HIGH PRESSURE THEN BUILDS OVER THE REGION
SUNDAY AND SUNDAY NIGHT WITH DRY WEATHER. FORECAST TEMPERATURES
WERE GENERALLY IN LINE WITH THE MAV GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
WE USED HPC GUIDANCE AS A STARTING POINT AND ONLY MINOR
ADJUSTMENTS WERE MADE.
A COLD FRONT IS EXPECTED TO SWEEP THROUGH THE REGION TUESDAY,
BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS. THE FRONT LOOKS TO
STALL OFF TO OUR SOUTH AND EAST BUT DEPENDING ON THE TRACK OF
HURRICANE IKE, IT MAY ACTUALLY BE PUSHED CLOSER TO OUR BORDERS.
MEANWHILE, HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT AND PERSIST
THROUGH FRIDAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MOST TAF SITES REMAIN IN MARGINAL VFR CATEGORY, BUT A CHANGE TO
IFR CONDITIONS ARE EXPECTED EARLY THIS AFTERNOON AS TROPICAL STORM
HANNA CONITNUES TO MOVE INTO THE AREA. CONDITIONS WILL BE LOWEST
IN HEAVIER PRECIPITATION BANDS, INCLUDING ISOLATED CONVECTION,
THIS AFTERNOON AND EARLY TONIGHT.
GRADUAL IMPROVEMENT TO VFR SHOULD BE OCCURRING IN THE WAKE OF THE
LOW LATER ON TONIGHT, AS THE WEST TO NORTHWEST WINDS KICK IN.
A WIND SHEAR REMARK WAS USED FOR THIS AFTERNOON AND EVENING. WIND
DIRECTIONS MAY NOT BE TOO FAR DIFFERENT FROM SURFACE VALUES, BUT
SPEEDS SHOULD INCREASE MARKEDLY OFF THE SURFACE, AND THE ATTEMPT WAS
MADE TO ALERT PILOTS OF INCREASED SPEEDS ABOVE THE GROUND.
&&
.MARINE...
THE APPROACH AND PASSAGE OF TROPICAL STORM HANNA WILL CAUSE A
DRAMATIC INCREASE IN WINDS DURING TODAY, WHICH SHOULD PEAK LATER
THIS AFTERNOON AND THIS EVENING. PLEASE REFER TO THE LATEST
STATEMENTS FROM THE NATIONAL HURRICANE CENTER AND OUR LOCAL HANNA
STATEMENTS FROM THE MT HOLLY NJ NATIONAL WEATHER SERVICE OFFICE FOR
ADDITIONAL DETAILS. 925 HPA WINDS WERE FORECAST TO BE IN THE 50 TO
55 KNOT RANGE AS THE LATEST FORECAST TRACKS THE STORM THROUGH THE
DELMAR AREA, THROUGH SOUTHEASTERN NEW JERSEY, AND THEN OFF THE NEW
JERSEY COAST THIS EVENING. SEAS ARE PROGGED UP TO 12 FEET OVER THE
EASTERN COASTAL WATERS THIS AFTERNOON AND THIS EVENING, WITH
BREAKERS IN THE SURF ZONE OF 5 TO 8 FEET. THIS IS IN LINE WITH THE
LATEST WAVEWATCH FORECAST.
WEAK HIGH PRESSURE IS EXPECTED TO BUILD OVER THE REGION IN THE WAKE
OF THE STORM FOR SUNDAY AND MONDAY. WIND SPEEDS AND SEAS WILL
SUBSIDE AT THAT TIME. A COLD FRONT FROM THE NORTHWEST IS SLATED TO
ARRIVE ON TUESDAY WITH AT LEAST SCATTERED ADDITIONAL PRECIPITATION.
SWELLS FROM IKE MIGHT BE BLOCKED ON MONDAY AND TUESDAY, BUT AS HIGH
PRESSURE BUILDS INTO THE REGION BEHIND THE FRONT, NORTHEAST SWELLS
REACHING SMALL CRAFT ADVISORY LEVELS MIGHT OCCUR WEDNESDAY.
&&
.RIP CURRENTS...
AS TROPICAL STORM HANNA APPROACHES FROM THE SOUTH TODAY, RIP
CURRENTS ARE EXPECTED TO BE MOSTLY IN THE RANGE OF HIGH. AN IN-HOUSE
GUIDANCE TOOL INDICATED MODERATE FOR DELAWARE, BUT IT DOES NOT SEEM
REASONABLE TO SPLIT OUT DELAWARE FOR MODERATE AND LEAVE NEW JERSEY
HIGH.
THE THREAT OF ENHANCED RIP CURRENTS SHOULD SUBSIDE SOMEWHAT FOR
SUNDAY INTO MONDAY AS HANNA MOVES TO OUR NORTHEAST AND FARTHER AWAY
FROM OUR REGION. HOWEVER, SWELLS FROM IKE MAY BEGIN TO ARRIVE ABOUT
THAT TIME. EVEN IF THAT DOES NOT OCCUR, THE EXPECTED NORTHEAST FETCH
MIGHT INCREASE RIP CURRENTS AGAIN BY WEDNESDAY.
&&
.TIDES AND COASTAL FLOODING...
WE ARE FORTUNATE THAT HANNA IS ARRIVING DURING THE NEAP TIDE CYCLE,
AS WELL AS WHEN TIDES, ON THE OCEAN AT LEAST, ARE STARTING TO MOVE
TOWARD LOW TIDE. SO, THE HIGHER ASTRONOMICAL TIDES TODAY ALONG THE
OCEAN-FRONT SHOULD BE ARRIVING AROUND THE TIME WINDS JUST START TO
RAMP UP AT MIDDAY AND EARLY AFTERNOON. THERE WILL BE A BETTER
COINCIDENCE OF WINDS AND TIDES IN THE BAYS AND THE TIDAL DELAWARE
RIVER. NEVERTHELESS, THE GENERAL SURGE IS EXPECTED TO AVERAGE 1 TO 3
FEET WHICH WOULD TAKE MOST LOCAL AREAS INTO THE MINOR TIDAL FLOODING
RANGE. CURIOUSLY, THE SURGE GUIDANCE IS LESS THAN THIS, ESPECIALLY
THE GFS WHICH SHOWS ONLY A FEW TENTHS ABOVE NORMAL. BUT, WITH
ONSHORE TO SOUTH WINDS OF TROPICAL STORM FORCE, OR AT LEAST FREQUENT
GUSTS (AS THE 925 HPA WINDS WERE 50 TO 55 KNOTS OVER THE WATERS),
THE STORM SURGE WILL BE FORECAST HIGHER THAN THE GUIDANCE. WAVE
ACTION ALSO HAS TO BE ADDED ON TOP OF THIS, AS WELL AS DRAINAGE
FLOODING THAT WILL OCCUR AROUND THE TIME OF HIGH TIDE AS HEAVY RAIN
SHOULD BE OCCURRING. LASTLY, MINOR TIDAL FLOODING MIGHT PERSIST INTO
SUNDAY ALONG TIDAL SECTIONS OF THE DELAWARE RIVER BECAUSE OF THE
FRESHWATER RUNOFF.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...TROPICAL STORM WIND WARNING UNTIL 11 PM EDT THIS EVENING FOR
PAZ067>071.
FLOOD WATCH THROUGH LATE TONIGHT FOR PAZ054-055-060>062-
067>071.
WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR PAZ054-055-
060>062.
NJ...TROPICAL STORM WIND WARNING UNTIL 11 PM EDT THIS EVENING FOR
NJZ001-007>010-012-015-017>019.
FLOOD WATCH THROUGH LATE TONIGHT FOR NJZ001-007>010-012>027.
TROPICAL STORM WARNING FOR NJZ013-014-016-020>027.
DE...FLOOD WATCH THROUGH LATE TONIGHT FOR DEZ001>004.
TROPICAL STORM WARNING FOR DEZ001>004.
MD...FLOOD WATCH THROUGH LATE TONIGHT FOR MDZ008-012-015-019-020.
TROPICAL STORM WARNING FOR MDZ008-012-015-019-020.
MARINE...TROPICAL STORM WARNING FOR ANZ430-431-450>455-470.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...ROBERTSON/STAUBER
SHORT TERM...STAUBER
LONG TERM...MEOLA
AVIATION...RPW/
MARINE...
RIP CURRENTS...
TIDES...
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