FXUS61 KPHI 051934
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
234 PM EST SAT DEC 5 2009
.SYNOPSIS...
LOW PRESSURE EAST OF VIRGINIA WILL INTENSIFY AS IT HEADS NORTHEAST
TONIGHT. THE LOW WILL PASS EAST OF NEW JERSEY THIS EVENING. HIGH
PRESSURE IS FORECAST TO BUILD ACROSS OUR REGION SUNDAY AND MONDAY.
A DRY COLD FRONT FROM THE NORTHWEST IS ANTICIPATED TO ARRIVE
MONDAY NIGHT. HIGH PRESSURE SHOULD FOLLOW FOR TUESDAY. STRONG LOW
PRESSURE FROM THE SOUTHWEST IS EXPECTED TO PASS OVER THE
NORTHEASTERN STATES ON WEDNESDAY AND WEDNESDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
PREVIOUS TRENDS HAVE CONTINUED. TEMPERATURES FELL THROUGHOUT THE
DAYLIGHT HOURS TODAY AND THIS WILL CONTINUE TONIGHT. WITH
PRECIPITATION ACROSS THE AREA, ANY RAIN WILL CHANGE OVER TO SNOW
FROM THE WEST. THIS HAS ALREADY OCCURRED ACROSS MOST AREAS TO THE
EST OF THE DELAWARE RIVER SOUTHWEST TO AREAS JUST WEST OF DOVER
DE. TOTAL SNOWFALL AMOUNTS WILL AVERAGE 1 TO 3 INCHES, BUT SOME
AREAS MIGHT SEE 4 INCHES, ESPECIALLY IN THE AREAS TO THE WEST OF
PHILA WHERE IT HAS SNOWED LONGER. HOWEVER, MOST OF THE
ACCUMULATION WILL BE ON GRASSY AREAS SINCE THE GROUND TEMPERATURES
ARE WELL ABOVE FREEZING. HOWEVER, SNOW MAY ALSO ACCUMULATE ON
ROADWAYS THIS EVENING AS TEMPERATURES GET CLOSER TO FREEZING AND
ANY INCREASE IN SNOWFALL INTENSITY WOULD ALLOW IT TO LAY ON THE
ROADS. THE WINTER WEATHER ADVISORY PREVIOUSLY ISSUED REMAINS VALID.
ANY LINGERING PCPN WILL END BY MIDNIGHT WITH SKIES CLEARING
QUICKLY. WITH FRESH SNOW ON THE GROUND IN MANY AREAS, TEMPERATURES
WILL FALL WELL DOWN INTO THE 20S. WHERE THERE ISNT A SNOW COVER,
LOWS WILL BE IN THE LOWER 30S. THE MAV/MET TEMPS DONT HAVE SNOW
COVER IN THEM SINCE THERE WAS NOT AT 12Z, THEREFORE THESE NUMBERS
LOOK A BIT HIGH.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
HIGH PRESSURE AND DRY CONDITIONS ARE FORECAST TO BUILD INTO OUR
REGION FROM THE WEST FOR SUNDAY AND MONDAY. HOWEVER, SOME MID AND
HIGH CLOUDS ARE EXPECTED SUNDAY NIGHT INTO MONDAY DUE TO WEAK
UPPER AIR DISTURBANCES MOVING THROUGH THE AREA.
FORECAST TEMPERATURES ARE EITHER WITH THE LOWER OF THE MET/MAV
GUIDANCE OR A BIT BELOW DUE TO LEFTOVER SNOW COVER AND A COLD
AIRMASS IN PLACE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL MOVE OFFSHORE BY TUESDAY AFTERNOON AS A STRONG
AREA OF LOW PRESSURE STARTS TO MAKE ITS WAY EASTWARD FROM THE
MIDWEST. AS A RESULT OF THE TRACK OF THE LOW, WE ARE PUT INTO THE
WAA AHEAD OF THE WARM FRONT, WITH AN ONSHORE FLOW TUESDAY NIGHT
INTO WEDNESDAY. THE WARM FRONT CROSSES ON WEDNESDAY FOLLOWED BY
THE COLD FRONT THAT EVENING. WE ARE EXPECTING TO GET SOME MORE
MIXED PRECIPITATION FROM THIS EVENT. DYNAMIC COOLING MAY OCCUR AS
THE RAIN FALLS CAUSING IT TO MIX AND POSSIBLY CHANGE OVER TO SNOW.
NORTHERN AREAS ARE MORE LIKELY TO SEE A STRAIGHT SNOW EVENT.
THE LOW CLEARS OUT BY EARLY THURSDAY WITH ALL PRECIPITATION EXPECTED
TO END BEFORE THEN. HIGH PRESSURE BUILDS IN FOR THURSDAY AND MOST OF
FRIDAY BRINGING AT LEAST A COUPLE OF DRY DAYS IN A ROW TO THE REGION.
ANOTHER SYSTEM MAY APPROACH FOR FRIDAY NIGHT INTO SATURDAY AND WE
HAVE INCLUDED CHANCE POPS FOR PRECIPITATION, WHICH ONCE AGAIN MAY BE
A MIXED BAG.
TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL THROUGH THE PERIOD.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
LOW CONDITIONS HAVE ARRIVED AT MOST OF THE TERMINALS AS OF THE EARLY
AFTERNOON. THE POOR CONDITIONS WILL CONTINUE UNTIL THE EVENING AS
THE LOW TRACKS ALONG THE COAST. AREAS THAT HAVE SNOW WILL CONTINUE
TO HAVE SNOW AND SITES WITH RAIN WILL CHANGE TO SNOW DURING THE REST
OF THE AFTERNOON. IFR CONDITIONS WILL REMAIN UNTIL THE BACK EDGE OF
THE PRECIP MOVES THROUGH AROUND 04Z-06Z TONIGHT. VFR CONDITIONS WILL
RESUME THEN WITH A GUSTY NW WIND.
OUTLOOK...
HIGH PRESSURE BUILDS IN FOR SUNDAY WITH LITTLE IN THE WAY OF CLOUDS
AND A NORTHWEST WIND AT ABOUT 10 KNOTS OR LESS. THIS HIGH PRESSURE
SYSTEM THEN SLIDES TO OUR EAST MONDAY AS A WEAK FRONT MAY SLIDE
THROUGH MONDAY NIGHT INTO TUESDAY. A POTENTIALLY SIGNIFICANT STORM
MAY THEN ARRIVE WEDNESDAY INTO THURSDAY.
&&
.MARINE...
MARINE FLAGS WILL REMAIN AS THEY ARE WITH JUST THE BEGINNING TIME OF
THE GALE BEING MOVED UP A FEW HOURS ON THE NORTHERN COASTAL WATERS.
THE SCA FLAG WILL FLY OVER THE NORTHERN DELAWARE BAY. LOW PRESSURE
WILL DEEPEN AND MOVE ALONG THE COAST OVERNIGHT AND THEN OFF INTO THE
NORTH ATLANTIC ON SUNDAY. NORTHEAST WINDS WILL BACK AROUND TO NW
TONIGHT AND REMAIN GUSTY. SCA FLAGS WILL LIKELY BE NEEDED FOR AWHILE
AFTER THE GALE FLAGS COME DOWN ON SUNDAY.
HIGH PRESSURE WILL BUILD OVER THE WATERS ON SUNDAY AND REMAIN NEARBY
THROUGH TUESDAY. ANOTHER LOW WILL AFFECT THE WATERS WEDNESDAY AND
THURSDAY WITH MORE SCA FLAGS NEEDED THEN.
&&
.TIDES/COASTAL FLOODING...
MINOR TIDAL FLOODING OCCURRED EARLIER TODAY WITH THE HIGH TIDE ALONG
THE COAST. SUNDAYS TIDES WILL LIKELY BE LESS THAN TODAY'S...SO WHILE
IT MIGHT BE CLOSE...I AM NOT CALLING FOR ANY MINOR TIDAL FLOODING AT
THIS POINT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ070-
071.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ054-
055-060>062-067>069.
NJ...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ008-
010-012-013-015>019.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NJZ001-
007-009.
DE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DEZ001.
MD...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MDZ008-
012-015.
MARINE...GALE WARNING UNTIL 5 AM EST SUNDAY FOR ANZ431-452>455.
GALE WARNING UNTIL 5 AM EST SUNDAY FOR ANZ450-451.
SMALL CRAFT ADVISORY UNTIL 5 AM EST SUNDAY FOR ANZ430.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...STAUBER
SHORT TERM...STAUBER
LONG TERM...MEOLA
AVIATION...O'HARA
MARINE...O'HARA
TIDES/COASTAL FLOODING...O'HARA
