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Area Forecast Discussion (AFD)

Issued by State College, PA (CTP)

FXUS61 KCTP 141048

Area Forecast Discussion
National Weather Service State College PA
648 AM EDT Sat Sep 14 2019

A cold front will move through today. The cold front will clear
out the low clouds and showers, and usher in many days of dry 
weather with temperatures at or above normal.


Low clouds remain over a good portion of the CWA, with elevated
showers and thunderstorms rolling overhead. The storms have,
impressively, gone >100sm into/over the soupy murk of the cold 
wedge. It appears that the cold front is somewhere along a  
BUF-CAK line at 09Z based on the dry air moving thru CLE right 
now. This may be a little faster than earlier thought, but the 
front will not be too quick to move through the area today. But,
this may end the threat of showers earlier than expected for 
the NW. 

By noon, the axis of the most likely area for showers will be 
over IPT-UNV-JST. Quite dreary dreary and damp compared to our 
most recent two Saturdays. 

The showers will continue to slip E/SE thru the aftn and by
sunset should be confined to just the SErn-most 2-3 counties.
Clearing is expected over the NW around mid-day after the weak
front moves past, but additional cu could form there behind the
front. The far SErn counties could get a little sunshine today
as the warm front bubbles up from the SE. If they do, there
could be a rumble of thunder there as the front passes through
in the evening. 

Max temps will likely be lower than national blend of guidance
again today due to the overall cloudier forecast.


After the showers and storms move out of the SE late in the 
evening, we should have a decent amount of clearing. Wind dies 
off as well. That should help a widespread fog to form as we'll 
have a good amount of low level moisture after these cool, damp 
days and the rainfall today. Mins will stay in the 60s SE but 
get close to 50F in the nrn mtns. 

After the fog burns away (slowly) on Sunday, it should be a 
much brighter, milder day. We could even top normal maxes by 5 
degs in many places.


Medium range guidance keeps us pretty close to the southern 
edge of the westerlies which lowers the forecast confidence for 
rain chances through the extended. A weak cold front might bring
a brief shower to the nrn mtns late Sunday night into Monday.

From there the models pop up the ridge over the Miss Valley
which leads to a developing NW flow aloft over the local area.
That should favor dry conditions through majority of next week.

Ridge axis shifts east by late next week, with ridge axis and
surface high along the east coast. Latest projected track of
potential tropical storm Humberto brings it northward off of 
the FL/GA coast then drifting eastward away from the mainland. 
Some models do turn it back northward by late next week, but 
majority of guidance currently keeps it on a ENE track away 
from the U.S.


A dwindling band of showers and thunderstorms will push into
central Pa early this morning ahead of an approaching cold
front. However, the main issue for aviation will be the stratus
which covers all of central Pa. A moist sse flow, combined with
orographic lift, will keep the higher elevations of central Pa 
in the IFR/LIFR category this morning, while the lower 
elevations further east experience MVFR cigs. 

Model soundings indicate low level moisture will begin mixing 
out ahead of approaching cold front later today, mainly across 
the southern and western part of the forecast area. However, 
the heating associated with brightening skies could lead to an 
afternoon thunderstorm in spots. Elsewhere, expect stubborn MVFR
cigs to hang on until arrival of the front during the evening 
over the eastern half of the state. 

High pressure will build in behind the front tonight. Clearing
skies, light wind and wet ground in spots will likely promote
the development of valley fog. 


Sun...AM valley fog possible.

Mon...No sig wx expected.

Tue...Patchy AM valley fog possible northern Pa.

Wed...No sig wx expected.




NEAR TERM...Dangelo
SHORT TERM...Dangelo