Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 232236

Area Forecast Discussion
National Weather Service State College PA
636 PM EDT Sun Oct 23 2016

A cold front will pass through tonight and early Monday bringing a
cold rain to the northern half of the state. A reinforcing shot
of cold air will follow and last through mid week.


Cu field will disappear for the most part this evening. But a
low-amplitude fast-moving wave will cross the upper Great Lakes
this evening and move across NY/PA early tonight. Weak low
pressure will ripple across at the sfc and drag a cold front thru
around 03Z in the NW and by 12Z SE. A streak of rain of 0.25-0.5"
is expected across the northern third of the area, while lower
amounts will fall as far S as FIG-UNV-IPT. However, not much rain
is expected S of that line. Will keep a few hundreths in the QPF
grid in the central mtns for 06-12z. NW flow will make isold- sct
shra in the Laurels in that same time frame. Temps will drop as
the rain starts in the NW, and diminish more-normally across the
rest of the area, as the timing of the front is mainly with the
normal nocturnal trend. Mins in the 40s widespread tonight as the
SE will be mainly cloud-free and drop more than the cloudy/wet
nrn tier.


NW post-frontal flow will keep isold-sct shra for the usual
suspects on Monday. High pressure stays to the W thru the short-
term and the tight pres grad will keep it breezy. Temps will only
rise 6-8F on Mon in the NW, and 10-15F in the SE under constant
but weak cold advection. The flow lasts into Mon Night, and the
temps get cold enough then to get a mix or plain ol` --sn for
precip type in the higher elevation of the nrn mtns. As with last
night, no accums expected with still-warm ground and very
light/sct precip.


Surface high pressure gradually works in from the Great Lakes Tue
into Wed keeping below normal temperatures in place. Cyclonic
flow/cold air aloft on Tue may bring enough instability to kick
off a few light showers in the NW mountains.

CAA comes to an end on Wed as weak progressive upper ridge
moves through as low-level flow turns back to the S/SW. Could see
a decent frost Wed morning as dewpoints bottom out.

A compact low developing over the Midwest will already be
knocking on our door by Thu. Drier air remains in place over the
east Wed night, but expect showers to work into the west
overnight. Rain becomes likely for much of the area on Thu.

Model guidance continues to diverge after that, especially at the
surface, so confidence in next weekends forecast remains rather
low. But a look at the upper pattern suggests general NW flow
keeping a steady stream of cooler air feeding into the region,
with a series of shortwave troughs sliding through.


A fast-moving low pressure system over the Grt Lks will track
across Northern Pa tonight, bringing a period of rain to that part
of the state. A core of strong winds aloft will precede this
system, likely resulting in LLWS overnight across much of Central
Pa. The exception may be at KJST, where climatology and model
soundings suggest the strong winds will mix to ground level,
resulting in wgusts to around 35kts. The threat of LLWS should end
from north to south after midnight, as strong winds aloft slip
south of the state.

The other concern will be the possibility of low cigs overnight
at KBFD and KJST, as plume of low level moisture ahead of trailing
cold front ascends the higher terrain of West Central Pa. Model
soundings indicate a possibility of tempo IFR cigs at KBFD between
04Z-12Z and at KJST between 08Z-14Z.

Moisture flowing off of Lk Erie will produce fairly widespread
stratocu across Central Pa on Monday. Model soundings suggest MVFR
cigs could linger most of the day at KBFD/KJST, while predominantly
VFR conds expected elsewhere.


Mon Night-Tue...MVFR/sct -shrasn N/W. VFR elsewhere.

Wed...No sig wx.

Thu...Widespread showers.

Fri...MVFR/sct -shra N/W. VFR elsewhere.




NEAR TERM...Dangelo
SHORT TERM...Dangelo
AVIATION...Dangelo/Fitzgerald is the U.S. government's official web portal to all federal, state and local government web resources and services.