FXUS61 KPHI 260200
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
900 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/...
MOST OF THE LIGHT RAIN HAD DIMINISHED IN THE WAKE OF THE WEAK
TROUGH AND UPPER LEVEL SHORT WAVE EARLY THIS EVENING. HOWEVER, FOG
WAS INCREASING, AND THIS WILL BE EMPHASIZED A LITTLE MORE. ALSO,
PATCHY DRIZZLE WILL BE INCLUDED OVERNIGHT AS WELL. ABUNDANT LOW
LEVEL MOISTURE REMAINS IN PLACE AND THESE CONDITIONS WILL PLAGUE
HOLIDAY TRAVELERS INTO TONIGHT. SOME SUBSIDENCE BEHIND THE
VORTICITY MAXIMUM SHOULD KEEP MOST OF TONIGHT PRECIPITATION-FREE,
BUT A SMALL CHANCE WILL BE LEFT FOR THE FAR NORTHWESTERN ZONES.
HOWEVER, WITH THE LOW LEVEL MOISTURE, FOG WILL DEVELOP OVERNIGHT
AND COULD DROP VISIBILITIES TO BELOW 1/2 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 /02Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

LOW LEVEL MOISTURE WILL REMAIN TRAPPED IN OUR REGION TONIGHT.
CEILING AND VISIBILITY VALUES ARE EXPECTED TO LOWER EVEN FURTHER
DURING THE COURSE OF THE NIGHT, WITH SOME DRIZZLE FROM TIME TO
TIME.

WITH A WEAK TEMPERATURE INVERSION REMAINING OVERHEAD AND WITH LITTLE 
HELP FROM THE LOW SUN ANGLE, CONDITIONS WILL LIKELY BE SLOW TO 
IMPROVE ON THURSDAY MORNING. FOR NOW, WE HAVE KEPT IFR CONDITIONS 
INTO THE LATE MORNING, WITH AN IMPROVEMENT INTO THE MVFR RANGE FOR 
THE AFTERNOON.

THE WIND WILL BE LIGHT AND VARIABLE THROUGH MOST OF THE TAF PERIOD, 
WITH PERHAPS A LIGHT NORTHERLY WIND DEVELOPING ON THE COASTAL PLAIN 
ON THURSDAY AFTERNOON.

OUTLOOK...
A COLD FRONT FROM THE WEST IS FORECAST TO ARRIVE ON THURSDAY NIGHT, 
BRINGING SHOWERS TO OUR REGION INTO FRIDAY. STRONG LOW PRESSURE IS 
EXPECTED TO MOVE UP INTO NEW ENGLAND FOR FRIDAY AND FRIDAY NIGHT, 
PRODUCING A GUSTY WEST TO NORTHWEST WIND. HIGH PRESSURE SHOULD BUILD 
IN FROM THE WEST FOR SATURDAY, SUNDAY AND MONDAY.

&&

.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 11Z
(6AM). SEAS AT THE DELAWARE BAY BUOY WERE STILL AROUND 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 6 AM EST THURSDAY FOR ANZ450>455.

&&

$$

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