Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 250333
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1133 PM EDT Fri Mar 24 2017

.SYNOPSIS...
A warm front will push north of the region Saturday before
sagging south ward across central Pennsylvania Saturday night
and Sunday. Very mild conditions are expected tonight and Sunday
as we enjoy the warm sector south of the frontal boundary.
However...increasing clouds and southeast flow are expected on
Sunday as the boundary sags southward as a backdoor cold
front...bringing cooler conditions and eventually some patchy
drizzle or light rain. Unsettled conditions will last from late
Sunday through Tuesday as a series of disturbances interact with
the front. No heavy rain is expected during this timeframe
however.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The surface warm front is bisecting the state this evening from
north to south with 01Z readings ranging from 67F at Bedford,
to 44F at Lancaster. Best WAA remains along and north of 850mb
baroclinic zone north of Pa, so little chance of any precip
overnight. Will maintain a low chance of a shower along the NY
border nearer to the periphery of east coast upper ridge.

Near term models indicate the warm front will stall out over the
central part of the state tonight, so expecting the coolest
overnight readings in the east. Lows into Saturday should range
from the 40s east, to the lower 50s over the western and
central mountains. There will be areas of low clouds and drizzle
in the vicinity of the NY border adjacent to the stalling sfc
boundary. Areas farther south stand to see the least cloud
cover.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
Near term models indicate even eastern Pa will break into the
warm air by late morning, but the warmup will be short-lived, as
high pressure building into New Eng pushes a backdoor cold front
through central Pa during the afternoon and evening hours. A
good deal of cirrus will hold temps down a bit, but even just
mixing to 925mb supports max temps in the upper 60s and low 70s
south of I-80. An earlier arrival of the front will result in
a cooler and cloudy day across the northern tier counties,
where southeast flow and nearly saturated soundings in the sfc-
850mb layer suggest patchy drizzle is possible. Further south,
there could be scattered afternoon showers in the increasingly
warm and unstable air over southern Pa...but most will stay dry.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Frontal boundary sags back into the region from the north
(pushed by a high pressure area sliding SE across S Ontario) on
Sunday as a low approaches from the Ohio Valley. This will sag
cooler and more moist air into the region. Light showers/drizzle
possible through much of the day, but main precip event impacts
central PA Sun night into early Mon as low moves through. QPF
looks to be around 0.50 inch.

Temps Sunday will be noticeably cooler behind the backdoor cold
front and a likelihood of rain. However, above average
temperatures (especially nighttime) appear very likely through
early next week, as GEFS indicates PA remains beneath a mean
upper level ridge and plume of anomalous PWATs.

The chance of showers again spikes with passage of next
shortwave Tuesday into Wednesday and another one to start the
weekend.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Main change to 03Z TAF package is to add LLWS for the
overnight period, as winds just above the ground are
between 30 and 50 knots.

Earlier discussion below.

Just some high clouds as of early evening. Expect VFR
conditions to prevail early on tonight. MVFR and IFR
conditions later tonight into Saturday, as a cold front
over southern Canada sags southward later tonight into
Saturday. Not looking at a lot of rain and drizzle away
from northern PA early on. However, lower conditions to
slowly work southward into Saturday afternoon and evening.

Looking at mild, but at times, wet weather for the later
part of the weekend, into early next week.

Outlook...

Sun-Tue...Sub-VFR with periods of rain.

Wed...Mfvr to VFR.

&&

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

&&

$$
SYNOPSIS...DeVoir
NEAR TERM...Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...RXR
AVIATION...Martin



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