Area Forecast Discussion
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FXUS61 KCTP 230623
Area Forecast Discussion
National Weather Service State College PA
223 AM EDT Fri Sep 23 2016
There is a very low chance for an isolated shower to the north of
I-80 this afternoon into early tonight. Fair weather with
seasonably cooler temperatures is expected over the weekend.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Clear skies will prevail for central and southeastern areas
overnight...essentially a repeat of last night in terms of sky
cover and local fog formation. Expect an increase in mid and high
moisture over the northwest after midnight as decaying baroclinic
zone approaches from the eastern GLAKS. Any light southerly wind
and slight increase in surface dewpoints could keep nighttime lows
a few degrees warmer across the board.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
Recent warm spell should peak Friday ahead of approaching cold
front. Model 850mb temps surging to arnd 16C should translate to
max temps well into the the 80s over most of central Pa. Low level
convergence along cold front, combined with some meager CAPEs,
could support a few late day showers/storms across the northern
tier counties. However, bulk of forcing assoc with parent
shortwave is progged to pass north of the state, so will keep POPs
in the slight chance category. Model RH time sections support a
msunny forecast Friday over much of the area, although increasing
clouds expected during the afternoon across the northern tier
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
All model data pushes cold front through central Pa Friday
night with little in the way of upper level support or significant
deep layer moisture. Thus, expect a mainly dry fropa for much of
the area, with just a very low chance of light showers north of
I-80. Although cooler air will begin flowing in on a northerly
breeze, still anticipating another mild night overall with mins
from arnd 50F over the northern mtns to around 60F in the south.
If winds drop off to near calm across the north, could see some
late night valley fog, while an active northerly breeze precludes
fog issues elsewhere.
Models remain in good agreement in dry and seasonable weather
this weekend, as Canadian high pressure builds southeast into
Pennsylvania. Some of the colder spots in north-central PA look
to dip into the upper 30s Sunday morning, which is not unusual
for this time of year.
Forecast from Tuesday onward took a turn toward more uncertain
overnight but extended models beginning to rally around the latest
solution - albeit with a fair amount of variability. Large upper
low in vicinity of western Great Lakes now looking to be a more
significant player by midweek as ridge over western U.S. works
eastward (rather than anchoring in place). This will edge the
trough and slowly unwinding upper low into the Northeast behind an
occluding cold front Monday, with the upper low impacting weather
for much of next week. EC still a bit of an outlier with its
deeper and more progressive trough, while the GFS camps the upper
low over the region for several days. Thus, best forecast is to
mention chances for showers Tue (mainly west) and Wed-Thu
areawide with a return of slightly above normal temps. Broad SW
flow on Tue will transition to NW flow by Thu as temps cool back
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
High clouds continue to push southeast across the northern
airspace in advance of frontal boundary located over Lake
Ontario. Localized brief restrictions in fog remain possible
around daybreak. Widespread VFR expected for most of the period
with a very low chance for an isolated shower across the northern
1/3 airspace this afternoon into early tonight along the cold
front. Guidance is indicating post-frontal sub-VFR ceilings
reaching the northern airspace late tonight into early Saturday
and have added MVFR FM group 24/03-05z at KBFD/KIPT/KUNV.
Sat-Sun...Patchy AM fog possible with mostly clear days.
Mon-Tue...Increasing risk for showers/thunderstorms ahead of