883 
fxus61 kphi 050707 
afdphi 


Area forecast discussion 
National Weather Service Mount Holly New Jersey 
307 am EDT Sat Jul 5 2008 


Synopsis... 
high pressure over the Atlantic will continue to pump warm and 
humid air across our region for the next several days. A stalled 
front and impulses moving along it will provide a threat for showers 
and thunderstorms through the weekend. A stronger front may 
provide some relief by the middle of next week. 


&& 


Near term /through 6pm Saturday/... 
weak impulses riding along a nearly stationary front draped across 
the Delaware-Maryland-Virginia and southern New Jersey will provide the entire area 
with some much needed rain in the form of showers and 
thunderstorms. The greatest threat for thunderstorms appears to be 
nearest the front, but certainly given the unstable conditions, 
convective activity could fire up just about anywhere in the 
County Warning Area. The GFS continues to indicate a bias for convective activity 
north of phl, while the NAM favors areas south of phl. Have opted 
to side more with the NAM given it/S performance yesterday and 
this morning. Met guidance was weighted a little more heavily in 
deriving today/S probability of precipitation and temperatures as well. 


&& 


Short term /tonight through 6 PM Sunday/... 
the stationary front is prognosticated to lift north during the day on 
Sunday, providing yet another chance of shower and thunderstorm 
activity across the County Warning Area. Likely pops, as indicated by mav guidance 
and previous forecast package, seems reasonable and won't be 
tinkered with much here. Temperatures in the low 80s will seem a little 
cooler as compared to recent highs. 


&& 




Long term /Sunday night through Friday/... 
the stationary frontal zone will eventually weaken (or drift 
north) by early next week. This will leave US in a Summer pattern 
with a Bermuda high well to our south and east pumping in plenty 
of warm humid air. Showers and thunderstorms will continue to 
affect the area, mainly during the afternoon and evening hours. 
Computer models are now hinting that a stronger cold front may be 
able to cross the region Wednesday night. If this does indeed 
occur, the shower and thunderstorm pattern could possibly end 
Thursday. With plenty of clouds and shower activity around, high 
temperatures Sunday will only reach the lower to middle 80s in the 
philly metropolitan area. By Monday the heat begins to return with highs 
pushing into the upper 80s. Tuesday and Wednesday, and possibly 
even Thursday, could see the 90 degree mark once again. 


&& 


Aviation /06z Saturday through Wednesday/... 
a weak short wave brought showers and thunderstorms to southern 
portions of the forecast area last night. It has moved off to the 
northeast early this morning. In it's wake, we have plenty of low 
level moisture but hardly any flow. That will mean areas of light 
rain, drizzle, and fog this morning. With conditions varying from 
VFR all the way down to LIFR. Conditions will begin to improve 
after sunrise, but very slowly due to the lack of any significant 
surface flow. We do expect mainly VFR during the afternoon and 
evening hours, although there may be scattered showers, especially 
in our southern zones, that will cause conditions to drop to MVFR/ 
IFR. 


Outlook... 
because of the proximity of the front, and then because of a 
developing warm and humid flow as the Bermuda high begins to be the 
main influence, at least scattered showers and thunderstorms will be 
possible through the outlook period. 


&& 


Marine... 
the nearly stationary front over the middle Atlantic region will 
gradually weaken during the next few days as a large Bermuda high 
pressure system begins to control the weather over the western 
Atlantic. This scenario will give US light winds and small seas 
today into Sunday. Thereafter, light to moderate southerly winds 
will prevail into the middle of next week, but both winds and seas 
are expected to remain below Small Craft Advisory criteria. The 
only fly in the ointment will be the possibility of showers and 
thunderstorms from time to time. 


&& 


Phi watches/warnings/advisories... 
PA...none. 
New Jersey...none. 
Delaware...none. 
Maryland...none. 
Marine...none. 


&& 


$$ 
Synopsis...miketta 
near term...miketta 
short term...miketta 
long term...O'Hara 
aviation...rpw 
marine...rpw