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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

                            
000
FXUS61 KCTP 231848
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
248 PM EDT Fri Aug 23 2019

.SYNOPSIS...
A large area of high pressure over the Great Lakes will drift 
gradually to the east, reaching northern New England on Sunday. 
This weather feature will bring us a several day string of dry 
and cooler weather with low humidity right into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The wave riding the front is finally moving far enough to the 
east to take the rain away from the SErn counties. Lower clouds 
are diurnal in nature and should die off quickly this evening, 
perhaps before sunset. The high clouds should linger thru 
midnight in the SE, but will be diminishing on the whole 
elsewhere. Air/river water temp difference to night will likely 
lead to the dendritic fog in the northern valleys. Some of the 
central valleys may also see fog try to form. Fog elsewhere is 
unlikely due to the dry air. Ought to be refreshing air. A small
taste of autumn, esp across the northwest half of the CWA. 
Thank the Canadians for this night's comfortable sleeping 
weather. 

&&

.SHORT TERM /SATURDAY/...
Fog burns away after an hour or two, and a mostly sunny day
results. Just a few cu over the mtns. Modified CP airmass 
visits for the weekend. Tough to beat guidance on maxes on days 
like Sat. Mixing gets up near 8H where Temps are 6-9C. We should
end up in the u60s across the higher hill tops of the west and 
north, and m70s in the warmer valleys of the east. These values 
are generally 4-8F below normal. 

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
An extensive area of high pressure will bring fair and dry 
weather to central PA this weekend. Weekend temperatures should
be near to slightly below normal for late-August, with a dry 
airmass providing pleasantly warm afternoons and comfortable 
nights.

Heading into next week, the question will be how quickly return
flow develops and brings moisture back into the area. The GFS 
continues to be a bit more bullish, bringing showers back into 
the region Monday, while the ECMWF delays the wet weather until
Tuesday. Given the uncertainty, went with a model blend and 
gradually increase PoPs Monday into Tuesday. PoPs should peak 
Wednesday with a frontal passage, with a drying trend for the 
later part of next week.

The temperature forecast becomes less certain early next week, 
as models develop southeasterly low-level flow that may advect 
clouds into the area and result in lower high temps Monday and 
Tuesday. Following the mid-week frontal passage, cooler and 
drier weather should return late next week.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
LE region of the strong jet streak and it's assocd wave along 
the front are sliding east and taking the rain to our east. Dry
air will win out and VFR will prevail for most of the next 60
hours. Some early morning fog is a given in the northern 
valleys. If it gets cold enough, the central valleys may also 
get fog, but the dryness of the air will likely balance that 
factor. The fog will be most likely between 08Z and 13Z. Poor
llvl mixing/light wind at first could mean it'll take a little 
longer than expected to burn the fog away. But, IPT is really 
the only site to worry about for tonight. BFD may fog at first, 
then go VFR again well before sunrise. 

.Outlook...

Sat-Sun...AM fog possible. 
Mon...AM fog possible. SE low level flow, low clouds poss. 
Tue...SHRA poss, mainly W.
Wed...CFROPA. SHRA/TSRA likely.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Evanego
AVIATION...Dangelo