Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 280646
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
246 AM EDT Fri Apr 28 2017

.SYNOPSIS...
A strong subtropical ridge will build westward from the Atlantic
Ocean over the weekend. We will be on the warm, moist western
side of the ridge most of the weekend. A strong trough should
bring cooler drier weather to the region for the second part of
next week.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
Trough overhead now, and so is the lightning and briefly
torrential rain. But, it is moving very quickly. A circulation
aloft is kinking what was previously a linear feature of
rain/thunder over the western mountains. The front appears to be
over KBFD- KAGC and moving eastward. The main problem along the
line is a long- lived cell with generally weak rotation but a
persistently strong updraft. Will have to watch for it as it
nears DuBois in a little over an hour. It has survived through a
fairly worked over area for a few hours. Heavy rain is still
possible to the NE of KUNV where the rain will ride over the
same area for a couple of hours.

Prev...
Showers and a few low-topped TSRA rolling through the western
highlands are already diminishing as they hit the stable air in
the central mountains. A second and perhaps third line moving in
are closer to the front and real westerly wind behind it. The
shortwave trough that has been driving this action is still a
few hours from passing. However, this stuff is moving into an
area where it has already rained this evening. With loss of
daytime heating, and already paltry CAPE to the east of the
current TSRA there should be a decrease in both coverage and
intensity through midnight. Almost nothing should be left by
then. Will mention some fog area-wide despite light west wind
as the dewpoints do not look like they will drop too far/fast
overnight away from the NW few counties.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM SATURDAY/...
Friday looks like a pretty decent day after a bit of a muggy
start in the SE half. Some left over clouds in the morning will
probably burn away with mixing and downslope. Maxes will still
be about 8-10F above normal.

For Friday night a boundary sets up over PA with a few waves
rippling along the boundary. There is some uncertainly on how
much instability is left over and exactly where this boundary
sets up. Some late convection could ride along the top of the
ridge and affect the northern counties.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Upper level ridge tries to builds in for Saturday to Sunday but
continued southerly flow and instability will lead to
additional chances for showers and storms - mainly in the
northern half of the area. Temps remain very warm into Monday.

Used superblend for this time period. Main feature will be a
massive cyclone that tracks through the Western Great Lakes from
Sunday night through Monday night. This will push a strong cold
front through PA and lead to another round of showers and
thunderstorms. Once this feature passes by much chillier air
will advect into PA with unsettled weather mainly for the
northern part of the state right into Wednesday.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Residual low level moisture ascending the Alleghenies will
result in areas of LMVFR cigs early this morning. Downslope flow
from west should keep central and eastern TAFs VFR with some
patchy/brief 1-3SM visibility possible if winds go calm. Drier
air working into the airspace along with high pressure will
support VFR conditions through the afternoon with mid-high
clouds increasing this evening into tonight.

Outlook...

Sat-Sun...Sct showers/Tstorms with periods of sub-VFR.

Mon...Breezy. Showers/thunderstorms likely with periods of sub-
VFR. FROPA.

Tue...Breezy with a chance of showers NW 1/2.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...BGM
AVIATION...Steinbugl


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