711 
FXUS61 KPHI 150824
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
424 AM EDT THU MAR 15 2012

.SYNOPSIS...
HIGH PRESSURE DROPPING SOUTH FROM NEW ENGLAND WILL RIDGE INTO OUR
REGION TODAY AND THEN BEGIN TO WEAKEN BY FRIDAY. A FRONTAL ZONE,
APPROACHING FROM THE WEST, WILL CROSS THE AREA FRIDAY AND FRIDAY
NIGHT, BEFORE MOVING OFF TO THE SOUTH AND EAST SATURDAY. A LARGE
AREA OF HIGH PRESSURE WILL THEN SETTLE OVER THE MID ATLANTIC
REGION AND DOMINATE OUR WEATHER INTO THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ALTHOUGH THE WEATHER IS NOT THREATENING TODAY, THE FORECAST IS 
CHALLENGING. THE NAM HAS HISTORICALLY DONE BETTER WITH THE SHALLOW 
COLD AIR THAT WAS DROPPING DOWN FROM THE NORTHEAST EARLY THIS MORNING, 
ALTHOUGH BOTH THE NAM AND GFS DO BRING LOW LEVEL MOISTURE DOWN INTO 
THE FORECAST AREA WITH THE AIR MASS. WE HAVE LEANED MORE TOWARD THE 
NAM THAN GFS WITH REGARD TO THE SOUTHERN PENETRATION OF THE HIGH AND 
HENCE WITH REGARD TO THE CLOUDS AND THE WINDS. WE ARE NOT PLAYING 
THE DRIZZLE CARD AT THIS POINT, AS EVEN THE NAM DOESN'T SEEM TO BE 
HITTING THAT REALLY HARD DURING THE NEAR TERM (ALTHOUGH YOU CAN FIND 
IT ALONG THE NJ COASTLINE IN BUFKIT). ON TEMPERATURES, THERE IS AN 
ABUNDANCE OF CHOICE BETWEEN THE MAV AND MET GUIDANCE. BASICALLY, THE 
FURTHER NORTHEAST IN THE FORECAST AREA ONE GOES, THE MORE OUR 
TEMPERATURES RESEMBLE THE COLDER MET VALUES. WELL SOUTH AND WEST, WE 
ARE PRETTY CLOSE TO THE MAV VALUES. THERE LIKELY IS GOING TO BE A 20 
DEGREE F OR GREATER TEMPERATURE DIFFERENCE ACROSS OUR REGION THIS 
AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
THE FORECAST CONTINUES TO LEAN TOWARD THE NAM DURING THIS PERIOD, 
WHICH MEANS WE CALL FOR STABLE AIR NEAR THE SURFACE WITH A 
RELATIVELY MOIST SOUTHWEST FLOW ABOVE A MOIST EASTERLY FLOW. THERE 
ARE AT LEAST A COUPLE OF WEAK SHORT WAVES ON TAP, AND THEY ARE 
EXPECTED TO GENERATE SOME FAIRLY WEAK LOW PRESSURE ALONG THE FRONT. 
WE HAVE THAT FRONT NEAR OUR FAR SOUTHERN ZONES, AND SO WE ARE GOING 
WITH A CHANCE OF RAIN AND DRIZZLE EVERYWHERE. ELEVATED INSTABILITY 
MAY AFFECT OUR SOUTHERN AND WESTERN ZONES LATE TONIGHT. TEMPERATURES 
AGAIN RESEMBLE MORE CLOSELY THE COLDER MET VALUES NORTHEAST AND THE 
WARMER MAV VALUES SOUTHWEST AS THE GUIDANCE REMAINS DISPARATE. 

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A SUBTLE SHORT WAVE AND WEAK AREA OF LOW PRESSURE WILL CROSS THE
REGION FRIDAY AND FRIDAY NIGHT. THIS WILL CREATE THE OPPORTUNITY
FOR SHOWERS AND ISOLATED TSTMS ON FRIDAY. POPS WERE ONLY CHANGES
SLIGHTLY...WITH LOW LIKELY POPS IN MOST AREAS FOR THE DAYTIME. THE
POPS WILL THEN DECREASE OVERNIGHT AND ONLY BE SLIGHT CHC FOR THE
SRN AND ERN AREAS SAT MORNING. THE SYSTEM IS RATHER PROGRESSIVE...SO
RAINFALL TOTALS WILL BE 1/4 INCH OR LESS.

HIGH PRESSURE BUILDS IN AT THE SFC AND ALOFT SUN-MON. THE FEATURE
REMAINS ACROSS THE AREA MUCH OF NEXT WEEK. THIS WILL LEAD TO
SEVERAL DAYS OF DRY AND WARM WEATHER FOR OUR AREA. HIGHS WILL BE
IN THE UPPER 60S OR LOW 70S MOST DAYS...WHICH IS 10 TO 15 DEGREES
ABOVE NORMAL FOR MID-MARCH. READINGS COULD REACH THE MID 70S IN
SOME AREAS...AWAY FROM THE OCEAN...ON TUE AND WED. 

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, 
KMIV, KACY AND SURROUNDING AREAS.

THE FORECAST IS A LOW CONFIDENCE ONE. PRESENTLY, WE FORECAST MAINLY 
VFR CONDITIONS AT ALL SITES EXCEPT ACY TODAY, BUT IF LOW CLOUDS 
CONTINUE TO ADVANCE THAT WILL CHANGE FOR THE WORSE. WE FORECAST MVFR 
CONDITIONS WITH VISIBILITY AND CEILING RESTRICTIONS EVERYWHERE 
TONIGHT DUE TO LIGHT RAIN OR DRIZZLE AND FOG. IFR CONDITIONS ARE 
POSSIBLE. WINDS SHOULD TAKE ON AN EASTERLY COMPONENT TODAY, BUT THEY 
ARE NOT EXPECTED TO BE MUCH IN EXCESS OF 10 KNOTS THROUGH THE TAF 
PERIOD. 

OUTLOOK...THE LOWER CONDITIONS FROM TONIGHT WILL CARRY INTO PART
OF FRI WITH LOWER CIGS/VSBYS IN SHOWERS AND ISOLATED TSTMS.
IMPROVING CONDITIONS BY SAT MORNING. VFR SAT AFTERNOON INTO MON. 

&&

.MARINE...
SUB-ADVISORY CONDITIONS ARE FORECAST THROUGH TONIGHT, ALTHOUGH THE 
SHALLOW COLD AIR MASS DROPPING ACROSS THE WATERS WILL CAUSE SOME 
MODERATE EAST WINDS OVER MOST OF THE ATLANTIC WATERS AND AN EASTERLY 
COMPONENT TO THE WINDS UP THE BAY. SEAS WILL RISE SOME IN RESPONSE, 
BUT ARE NOT FORECAST TO REACH FIVE FEET. 

OUTLOOK...THE SYSTEM THAT WILL AFFECT THE WATERS FRI MAY BRING
SEAS CLOSE TO 5 FT...BUT LOW CONFID IN THAT ATTM. SUB-SCA
CONDITIONS FOR THE WEEKEND AS HIGH PRESSURE BUILDS IN. 



&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...RPW/DELISI
NEAR TERM...DELISI
SHORT TERM...DELISI
LONG TERM...O'HARA
AVIATION...DELISI
MARINE...DELISI