000
FXUS61 KPHI 160900
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
500 AM EDT TUE MAR 16 2010
.SYNOPSIS...
LOW PRESSURE WELL OFF THE COAST FINALLY WILL BEGIN TO RELINQUISH ITS
HOLD ON OUR AREA TODAY. A LARGE AREA OF HIGH PRESSURE WILL
BUILD IN, ALTHOUGH A WEAK COLD FRONT MAY MOVE INTO THE AREA LATE
THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WATER VAPOR IMAGERY EARLY THIS MORNING WAS SHOWING THE MID LEVEL
VORTEX OFF THE COAST DROPPING SOUTH TOWARD THE SUB-TROPICAL JET,
THEREBY GIVING CREDENCE TO THE MODEL INDICATIONS THAT THE SYSTEM
THAT HAS DOMINATED OUR WEATHER FOR DAYS WILL FINALLY START TO MOVE
AWAY. DRIER AIR WAS ANALYZED AS DROPPING SOUTH FROM UPSTATE NY AT
00Z, AND INFRARED IMAGERY SHOWED DRYING AND CLEARING ADVANCING
TOWARD US. RADAR IMAGERY WAS LOSING ANY RETURNS NORTHWEST OF THE
I-95 CORRIDOR, AND DEW POINTS OVER OUR NORTHERN FORECAST AREA WERE
BEGINNING TO DROP /ALTHOUGH TEMPERATURES WERE REMAINING NEARLY
STEADY OR EVEN RISING A LITTLE/. WE EXPECT TO SEE SUNSHINE TODAY
FOR THE FIRST TIME SINCE LAST THURSDAY.
THERE WILL BE A MODERATE NORTHERLY WIND /A BIT STIFFER ALONG THE
COAST/ THAT WILL DIMINISH SOMEWHAT BY EVENING. GUIDANCE TEMPERATURES
ARE RATHER WARM COMPARED TO CONTINUITY, AND BOTH GFS AND NAM BUFKIT
SOUNDINGS HAVE THE NORTHERN PART OF THE FORECASTING AREA MIXING TO
NEAR H8 LATE IN THE DAY. GIVEN THE PROGGED H8 TEMPERATURES, WE
DECIDED TO RAISE TEMPERATURES TO NEAR GUIDANCE VALUES. MAX
TEMPERATURES MAY HAPPEN A LITTLE LATER IN THE DAY THAN NORMAL IF
BUFKIT SOUNDINGS ARE CORRECT. WE KEPT TEMPERATURES COOLER NEAR THE
COAST ON THE NORTH TO NORTHEAST WIND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
ALTHOUGH THERE WILL BE A WEAK UPPER JET RUNNING BY TO THE NORTH
TONIGHT, WE SHOULD SEE MAINLY CLEAR SKIES. THE BOUNDARY LAYER SHOULD
DECOUPLE AWAY FROM THE COAST, AND THE NIGHTS STILL ARE LONG ENOUGH
TO ALLOW FOR RADIATING. CONTINUITY CAPTURES THIS, AND SO WE SIDE
WITH IT AND GO BELOW THE COOLER STAT GUIDANCE. NAM BUFKIT SOUNDINGS
DO NOT SUPPORT FOG DEVELOPMENT AT ALL, WHILE GFS BUFKIT SOUNDINGS
ARE MARGINALLY MORE SUPPORTIVE UP NORTH. STAT GUIDANCE FORECASTS NO
VISIBILITY RESTRICTIONS EXCEPT FOR MPO, WHERE BOTH THE MAV AND THE
MET FORECAST SOME DENSE FOG. WE DECIDED TO KEEP THE MENTION OF
PATCHY FOG FOR THE THREE NORTHWESTERN COUNTIES LATE TONIGHT AND
EARLY TOMORROW MORNING. WITH THE DRIER AIR BUT VERY MOIST GROUND,
PERHAPS WE WOULD BE LOOKING AT A GROUND FOG SITUATION AT OTHER
LOCALES.
BUFKIT SOUNDINGS MIX ALMOST EVERYBODY TO OR NEAR H8 TOMORROW, AND
GIVEN THE PROGGED H8 TEMPERATURES WE AGAIN GENERALLY ACCEPT THE WARM
STAT GUIDANCE. THE H925 WINDS LOOK TO BE PRETTY WEAK THROUGH 18Z, SO
WE FORECAST A SEA BREEZE TO DEVELOP AND KEEP TEMPERATURES ALONG THE
COAST DOWN. WE AGAIN MAINLY ARE LOOKING FOR SUNNY SKIES.
WEDNESDAY NIGHT LOOKS LIKE A REASONABLY GOOD RADIATIONAL COOLING
NIGHT. THERE MAY BE AN OCCASIONAL LIGHT BREEZE /ESPECIALLY NORTH/,
AND THE DEW POINTS MAY BE A LITTLE HIGHER, BUT WE STILL SIDE WITH
CONTINUITY AND GENERALLY GO BELOW THE COOLER STAT GUIDANCE.
ON THURSDAY, WE MAY SEE A WEAK BACK DOOR COLD FRONT MOVE INTO OUR
AREA AS A MID LEVEL VORTEX NORTH OF LABRADOR MAY JUST MANAGE TO
NUDGE A LITTLE COOLER AIR AND A FEW CLOUDS INTO OUR NORTHWESTERN
ZONES. STILL, IT LOOKS LIKE ANOTHER DRY AND UNSEASONABLY WARM DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DRY WEATHER IS EXPECTED TO START THE EXTENDED OFF, WITH A CHANCE OF
RAIN BY THE END OF THE FORECAST PERIOD. A DRY BACKDOOR FRONT MAY
APPROACH THE AREA ON FRIDAY, THEN RETREAT NORTHWARD BY SATURDAY.
HIGH PRESSURE OFF THE COAST WILL HELP KEEP THE WEATHER DRY ON
SATURDAY. WITH A FRONTAL BOUNDARY APPROACHING AND PASSING SUNDAY
INTO MONDAY, RAIN CHANCES INCREASE. THE BEST CHANCE AT THIS TIME
LOOKS TO BE LATE SUNDAY INTO EARLY MONDAY, HOWEVER THERE MAY STILL
BE A CHANCE INTO THE DAY ON MONDAY. TEMPERATURES THROUGH THE
EXTENDED ARE EXPECTED TO BE ABOVE NORMAL FOR MUCH OF THE EXTENDED
UNTIL THE VERY END AFTER THE COLD FRONTAL PASSAGE.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THERE IS FINALLY IMPROVEMENT AT THE END OF THE TUNNEL AS OUR PESKY
LOW PRESSURE SYSTEM MOVES FARTHER AWAY FROM OUR AREA TODAY. MVFR TO
VFR CEILINGS ARE OCCURRING EARLY THIS MORNING WITH A FEW LIGHT
LINGERING SHOWERS OR EVEN SPRINKLES. SOME DRIZZLE CANNOT BE RULED
OUT EARLY THIS MORNING EITHER, HOWEVER THE BULK OF THE PRECIPITATION
IS WINDING DOWN. AS THE STORM CONTINUES TO MOVE FARTHER AWAY FROM
OUR LOCAL AREA DURING TODAY, DRIER AIR IS EXPECTED TO ARRIVE FROM
NORTHWEST TO SOUTHEAST. SATELLITE IMAGERY AND SURFACE OBSERVATIONS
ALREADY ARE SHOWING IMPROVEMENT TO VFR OCCURRING FROM ABOUT THE
KABE/KRDG AREA ON NORTH AND WESTWARD. THE SOUTHWARD IMPROVEMENT
MAY END UP OCCURRING FAIRLY QUICK AS DRIER AIR NEAR THE SURFACE
MOVES DOWN FROM NEW ENGLAND AND THE EASTERN GREAT LAKES. OVERALL, WE
CONTINUED THE IMPROVING TREND THROUGH THIS MORNING WITH ALL
TERMINALS GOING TO VFR BY MID-MORNING AND THE CLOUDS WILL THIN AS
WELL DURING THE DAY.
A NORTH TO NORTHEAST WIND WILL BE A BIT GUSTY FOR AWHILE THIS
MORNING AT SOME TERMINALS AS THE PRESSURE GRADIENT HOLDS ON FOR A
TIME. OVERALL THOUGH, THE WINDS WILL BE DIMINISHING THROUGH THE DAY,
ESPECIALLY TOWARD EVENING AS HIGH PRESSURE EDGES CLOSER. WE SHOULD
BE ABLE TO DECOUPLE TONIGHT WITH THE SURFACE WINDS GOING RATHER
LIGHT. THERE DOES NOT APPEAR TO BE MUCH IN THE WAY OF CLOUDS
TONIGHT, THEREFORE VFR IS EXPECTED.
OUTLOOK...
HIGH PRESSURE SETTLES MOSTLY TO OUR WEST WEDNESDAY AND REMAINS
MOSTLY IN CONTROL OF OUR WEATHER THROUGH SATURDAY. A SEA BREEZE MAY
DEVELOP WEDNESDAY AND THURSDAY AFTERNOONS AND AFFECT SOME OF THE
EASTERN TERMINALS. PERHAPS OF SOME CONCERN IS IF FOG CAN FORM AT
SOME SPOTS DURING THE EARLY MORNING HOURS WEDNESDAY AND THURSDAY
GIVEN THE LIGHT WINDS AND WET GROUND. OVERALL THOUGH, NO SIGNIFICANT
WEATHER IS EXPECTED DURING THIS TIME FRAME.
&&
.MARINE...
THE PERSISTENT SURFACE LOW IS FINALLY MOVING AWAY FROM OUR AREA
TODAY. THERE STILL REMAINS CYCLONIC FLOW ON THE WEST SIDE OF THIS
FEATURE WITH A TIGHTER PRESSURE GRADIENT. THE SURFACE WINDS HAVE
BEEN STRUGGLING TO GET TO GALE FORCE DURING THE NIGHT AND A
COMPARISON OF THE BUOY OBSERVATIONS TO THE SOUNDING DATA IN BUFKIT
SHOWS THAT THE MODEL DATA IS TO STRONG WITH THE WIND FIELD NEAR THE
SURFACE. THE STRONGEST WINDS ARE MOSTLY FORECAST TO OCCUR THROUGH
ABOUT 12Z AND THERE HAS BEEN LITTLE IN THE WAY OF GALE FORCE WINDS
REPORTED /EVEN FARTHER OFFSHORE/ BASED ON THE AVAILABLE DATA. SINCE
WIDESPREAD WINDS TO GALE FORCE ARE LOOKING LESS LIKELY, WE WILL
CANCEL THE WARNING AND DROP IT BACK TO A SMALL CRAFT ADVISORY. WE
WILL CARRY GUSTS TO AROUND 30 KNOTS THROUGH THE MORNING, THEN ALLOW
THESE TO SUBSIDE SOME DURING THE AFTERNOON AS THE PRESSURE GRADIENT
RELAXES. THE WINDS LOOK MORE MARGINAL ON DELAWARE BAY, HOWEVER THERE
HAVE BEEN SOME 25 KNOT GUSTS THEREFORE WILL CARRY AN ADVISORY
THROUGH 16Z TODAY. THE SEAS ON THE OCEAN WILL REMAIN ELEVATED FOR
AWHILE THEREFORE THE ADVISORY WILL BE CARRIED THROUGH WEDNESDAY NIGHT
FOR NOW.
HIGH PRESSURE THEN GRADUALLY BUILDS TOWARD OUR AREA THROUGH THE
REMAINDER OF THE WEEK. THIS WILL ALLOW THE SEAS TO SUBSIDE MORE
ALONG WITH PROVIDE LIGHTER WINDS. THERE MAY BE A SEA BREEZE
CIRCULATION THAT DEVELOPS WEDNESDAY AND THURSDAY AFTERNOONS, WHICH
WOULD TURN THE WINDS ONSHORE NEARSHORE AND FUNNEL UP DELAWARE BAY.
OTHERWISE, NO STORMS ARE EXPECTED THROUGH SATURDAY.
&&
.HYDROLOGY...
FLOODING CONTINUES ON THE PASSAIC, POMPTON, ROCKAWAY, WANAQUE,
MILLSTONE, METEDECONK, GREAT EGG HARBOR AND MAURICE RIVERS AND ON
THE NORTH BRANCH OF THE RANCOCAS CREEK. PLEASE SEE THE LATEST
WARNINGS AND STATEMENTS REGARDING THEIR STATUS, AS WELL AS
STATEMENTS REGARDING THE DELAWARE RIVER NEAR TRENTON AND THE
SUSQUEHANNA RIVER NEAR THE CONOWINGO DAM.
&&
.TIDES/COASTAL FLOODING...
SOME MINOR TIDAL FLOODING OCCURRED WITH THE LAST HIGH TIDE. THE
WATER LEVELS REMAIN ELEVATED DUE TO THE LINGERING ONSHORE FLOW AND
ALSO THE FRESHWATER RUNOFF. THE GFS STORM SURGE GUIDANCE HAS
BEEN RUNNING ON THE LOW SIDE DURING THE NIGHT. TAKING THIS INTO
ACCOUNT AND THAT THE SURGE IS ACTUALLY FORECAST TO INCREASE SOME
THROUGH TODAY BEFORE DROPPING OFF, WE WILL EXTEND THE COASTAL FLOOD
ADVISORY ALONG THE COAST AND DELAWARE BAY THROUGH 04Z WEDNESDAY TO
COVER THE HIGH TIDES THROUGH THIS EVENING. THE TIDAL PORTION
OF THE DELAWARE RIVER WILL HAVE THE ADVISORY EXTENDED THROUGH 10Z
WEDNESDAY TO ACCOUNT FOR THE HIGH TIDE THIS AFTERNOON AND AGAIN
EARLY WEDNESDAY MORNING. THE CONTINUED FRESHWATER RUNOFF WILL HELP
TO KEEP THE WATER LEVELS HIGHER THAN NORMAL. AS THE PESKY STORM
PULLS AWAY TODAY, WE ARE NOT EXPECTING LEVELS TO HIT MODERATE. THE
LEVELS WILL BE MONITORED THOUGH JUST IN CASE, AND ALSO IN THE EVENT
THE ADVISORIES NEED TO BE EXTENDED FARTHER OUT IN TIME.
IT APPEARS THAT WE SHOULD REMAIN BELOW MINOR FLOODING LEVELS ACROSS
THE EASTERN SHORE OF MARYLAND, THEREFORE NO ADVISORY ATTM.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...COASTAL FLOOD ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR PAZ069>071.
NJ...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
NJZ012>014-020>027.
COASTAL FLOOD ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR NJZ016>019.
DE...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
DEZ002>004.
COASTAL FLOOD ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR DEZ001.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ450>455.
SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ430-431.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...DELISI
SHORT TERM...DELISI
LONG TERM...ROBERTSON
AVIATION...GORSE
MARINE...GORSE
HYDROLOGY...DELISI
TIDES/COASTAL FLOODING...GORSE
