FXUS61 KPHI 252208
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
508 PM EST WED NOV 25 2009

.SYNOPSIS...
LOW PRESSURE WILL TRACK SLOWLY EASTWARD THROUGH THE GREAT LAKES 
REGION TONIGHT AND THURSDAY AS ANOTHER LOW PRESSURE SYSTEM ORGANIZES 
OFF THE EAST COAST. THESE SYSTEMS WILL MERGE ACROSS EASTERN NEW 
ENGLAND FRIDAY. A STRONG COLD FRONT IS FORECAST TO MOVE THROUGH OUR 
AREA FRIDAY MORNING. HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND AND 
LAST INTO MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST BY 
MONDAY NIGHT.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A LITTLE TROUGH WORKING EASTWARD THROUGH THE AREA AT LATE
AFTERNOON HAD SOME LIGHT RAIN WITH IT...SO POPS WERE INCREASED FOR
THE EARLY PART OF THE NEAR TERM SLIGHTLY, MAINLY NORTH AND EAST.
OTHERWISE, ABUNDANT LOW LEVEL MOISTURE REMAINS IN PLACE AND EVEN
THOUGH THERE HASN'T BEEN MUCH RAIN, IT IS DAMP AND DREARY. THESE
CONDITIONS WILL PLAGUE HOLIDAY TRAVELERS INTO TONIGHT. THERE COULD
BE SOME SHOWERS VIRTUALLY ANYWHERE THROUGH THE EVENING AS AN UPPER
LEVEL DISTURBANCE MOVES ACROSS THE AREA. AFTER THAT, SOME
SUBSIDENCE BEHIND THE VORTICITY MAXIMUM SHOULD KEEP MOST OF
TONIGHT PRECIPITATION-FREE. HOWEVER, WITH THE LOW LEVEL MOISTURE,
FOG WILL DEVELOP OVERNIGHT AND COULD DROP VISIBILITIES TO BELOW 1
MILE IN SOME LOCATIONS AT TIMES. ANYONE TRAVELING FOR THE
THANKSGIVING HOLIDAY SHOULD BE PREPARED FOR REDUCED VISIBILITIES
IN FOG. MOS GUIDANCE LOOKS REASONABLE FOR TEMPERATURES, WITH NOT
MUCH OF A DIURNAL CHANGE DUE TO THE CLOUD COVER.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THE LULL IN THE PRECIP WILL CONTINUE FOR MOST, IF NOT ALL, OF
TURKEY DAY, GIVING PEOPLE AN OPPORTUNITY TO GO AND WALK OFF SOME
OF WHAT THEY MAY EAT. WEAK HIGH PRES WILL BE SITUATED OVER THE
REGION THROUGH THURSDAY EVENING. THEN, A VERY STRONG H5 TROF WILL
APPROACH THE REGION. THE ASSOCD SFC LOW OVER SERN CANADA WILL MOVE
EWD AND COMBINE WITH A LOW CURRENTLY OFF THE SERN CONUS COAST.
THESE LOWS WILL MERGE OVER NRN NEW ENG/SERN CANADA AND SWING A
DECENT CDFNT AND VORT THROUGH THE REGION EARLY ON FRIDAY.
TEMPERATURES ON FRIDAY WILL BE ABOUT 10 DEGREES COLDER THAN ON
THURSDAY. ADDITIONALLY, THE PRESSURE GRADIENT BETWEEN THE
STRENGTHENING LOW OVER THE CANADIAN MARITIMES AND HIGH PRESSURE TO
THE SE WILL INCREASE ON FRIDAY INTO SATURDAY. AS A RESULT, THE
WIND WILL INCREASE FROM THE W TO NW AND BECOME GUSTY, MAKING IT
FEEL COLDER THAN IT ACTUALLY IS. POPS WILL INCREASE THURSDAY
EVENING INTO FRIDAY MORNING AND THEN DECREASE LATER FRIDAY. THERE
ARE SOME DECENT DYNAMICS WITH THE H5 TROF, SO A RUMBLE OF THUNDER
CAN NOT BE RULED OUT.

ALL PRECIP SHOULD COME TO AN END BY FRIDAY EVENING AS HIGH
PRESSURE BUILD IN. SATURDAY WILL BE DRY WITH A DECREASING WINDS
AND TEMPS SLIGHTLY BELOW NORMAL.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AT THE UPPER LEVELS, A TROUGH IS FORECAST TO BE LIFTING TO OUR 
NORTHEAST ON SATURDAY EVENING. MEANWHILE, A RIDGE IS EXPECTED TO 
EXTEND FROM THE SOUTHEASTERN STATES UP OVER THE UPPER MISSISSIPPI 
RIVER VALLEY AT THAT TIME. THE RIDGE AXIS SHOULD DRIFT TO THE EAST, 
PASSING OVERHEAD ON SUNDAY AFTERNOON. WE ARE FORECAST TO BE ON THE 
NORTHERN EDGE OF SURFACE HIGH PRESSURE FROM SATURDAY NIGHT INTO 
EARLY MONDAY, WITH DRY WEATHER AND NEAR SEASONABLE TEMPERATURES 
ANTICIPATED.

AN UPPER LEVEL TROUGH IS EXPECTED TO DROP ACROSS THE GREAT LAKES AND 
THE NORTHEASTERN STATES DURING THE MONDAY AND TUESDAY TIME FRAME. IT 
SHOULD PUSH A COLD FRONT THROUGH OUR REGION LATE ON MONDAY NIGHT OR 
EARLY ON TUESDAY. AS A RESULT, WE HAVE MENTIONED A CHANCE FOR 
SHOWERS. TEMPERATURES MAY BE LOW ENOUGH FOR SOME SNOW FLAKES UP IN 
THE POCONOS AND IN FAR NORTHERN NEW JERSEY.

THE SURFACE COLD FRONT IS FORECAST TO STALL OFF THE COAST. 
MEANWHILE, ANOTHER UPPER RIDGE SHOULD BUILD UP FROM THE SOUTHWEST 
WITH ITS AXIS PASSING OVERHEAD ON WEDNESDAY. HIGH PRESSURE IS 
EXPECTED TO PASS TO OUR NORTH AT THAT TIME, BRINGING DRY WEATHER TO 
OUR NORTHERN COUNTIES FROM LATE TUESDAY INTO EARLY WEDNESDAY. WITH 
THE SURFACE FRONT NEARBY, WE WILL KEEP SLIGHT CHANCE OR LOW CHANCE 
POPS FOR OUR SOUTHERN COUNTIES.

AN UPPER TROUGH IS EXPECTED TO BEGIN APPROACHING FROM THE SOUTHWEST 
ON WEDNESDAY, ALONG WITH SURFACE LOW PRESSURE FROM THE SOUTHWEST AND 
SOUTH. AS A RESULT, WE HAVE INCLUDED CHANCE POPS FOR RAIN IN THE 
FORECAST.

&&

.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

AN UPPER LEVEL TROUGH DIGGING INTO THE GREAT LAKES REGION AND THEN 
INTO THE OHIO RIVER VALLEY ON THURSDAY IS PROVIDING A SOUTH TO NORTH 
TRACK FOR WEAK STORMS ALONG THE EAST COAST. THE EASTERLY FLOW 
PRODUCED AT AND NEAR THE SURFACE BY THESE WEAK STORMS IS PRODUCING 
LOW CLOUDS AND DRIZZLE ACROSS MUCH OF THE FORECAST AREA THIS 
AFTERNOON, ALONG WITH IFR CONDITIONS, ESPECIALLY ON AND NEAR THE 
COASTAL PLAIN. WE EXPECT IFR CONDITIONS TO CONTINUE AT MOST OF OUR 
TAF SITES THROUGH THE AFTN HOURS, WITH POSSIBLY A FEW PERIODS OF 
MVFR CONDITIONS AS CEILINGS AND/OR VSBYS TEMPORARILY IMPROVE 
FROM TIME TO TIME. CONDITIONS MAY BE A LITTLE BETTER AT BOTH ABE AND 
RDG GIVEN THEY'RE A LITTLE FURTHER FROM THE COAST, BUT STILL MAINLY 
IFR CONDITIONS ARE EXPECTED THERE TOO.  

CONDITIONS COULD IMPROVE SLIGHTLY FOR A BRIEF PERIOD THIS EVENING
AS BOTH CEILINGS AND VSBYS COULD RISE TO MVFR CONDITIONS. HOWEVER,
GIVEN THE AMOUNT OF RESIDUAL MOISTURE IN THE AREA, VSBYS COULD
DROP TO 1SM OR LESS IN FOG. THE TAFS INCLUDE THIS PESSIMISTIC
OUTLOOK. NOT THE BEST WEATHER FOR ONE OF THE BUSIEST TRAVEL DAYS
OF THE YEAR.

SOME IMPROVEMENT TO MVFR OR VFR IS EXPECTED LATE THURSDAY MORNING 
INTO THURSDAY EVENING AS SLIGHTLY DRIER AIR MOVES IN.

OUTLOOK...
A COLD FRONT IS EXPECTED TO MOVE THROUGH FROM THE NW THURSDAY NIGHT. 
BRISK NW WINDS WILL DEVELOP BEHIND THE FRONT. SHOWERS ARE EXPECTED 
FRIDAY WITH MVFR AND POSSIBLY IFR CONDITIONS. THERE MAY ALSO BE SOME 
SNOW MIXED WITH RAIN SHOWERS MAINLY N/W OF PHL.  OVER THE 
WEEKEND...VFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
WEAK LOW PRESSURE WELL OFFSHORE WILL MOVE NORTHEAST PAST THE 
MID-ATLANTIC REGION TONIGHT. ANOTHER LOW PRESSURE SYSTEM IS EXPECTED 
TO DEVELOP OFF THE NORTH CAROLINA COAST, THEN INTENSIFY AS IT MOVES 
NORTHEAST THURSDAY NIGHT AND FRIDAY. THE CIRCULATION AROUND THIS LOW 
WILL PULL A COLD FRONT ACROSS THE REGION FROM THE NORTHWEST THURSDAY 
NIGHT. GALE FORCE WINDS ARE POSSIBLE FRIDAY INTO SATURDAY AS COLD 
AIR MOVES INTO THE REGION BEHIND THIS FRONT. MORE TRANQUIL WEATHER 
IS EXPECTED ON SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. 
ANOTHER STRONG COLD FRONT IS EXPECTED TO CROSS THE AREA MONDAY NIGHT.

THE SCA ON THE OCEAN HAS BEEN EXTENDED IN TIME, NOW ENDING AT 02Z 
(9PM). SEAS AT THE DELAWARE BAY BUOY WERE STILL OVER 5 FEET, AND 
JUST BELOW 5 FEET AT THE ENTRANCE TO NY HARBOR. WINDS ARE EXPECTED 
TO PICK UP THURSDAY NIGHT BEHIND THE COLD FRONT, AND GALE WARNINGS 
WILL LIKELY BE NEEDED FOR BOTH THE OCEAN AND THE DELAWARE BAY AS 
COLDER AIR MOVES OVER WARMER WATER. WINDS SHOULD DECREASE A BIT 
SATURDAY NIGHT AND EVEN MORE ON SUNDAY.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 PM EST THIS EVENING FOR 
     ANZ450>455.

&&

$$

SYNOPSIS...NIERENBERG / 
NEAR TERM...NIERENBERG / 
SHORT TERM...NIERENBERG
LONG TERM...IOVINO
AVIATION...MIKETTA
MARINE...MIKETTA