Area Forecast Discussion
Issued by NWS State College, PA

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946
FXUS61 KCTP 252228
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
628 PM EDT SAT JUN 25 2016

.SYNOPSIS...
High pressure will dominate the weekend before a cold front
approaches the area Monday. High pressure should return by
midweek.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Minor diurnal cumulus buildups are collapsing early this evening
as daytime heating wanes and sfc high pressure axis extends from
NE to SW across the region.

Fair weather will continue overnight with lows very near seasonal
norms, in the upper 50s to lower 60s from north to south. There
could be some patchy fog in the lower Susq, but it will mix out
quickly on Sunday.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
Another great early summer day is in store Sunday as high pressure
slips off to our east. Highs will reach into the 80s, even over
the higher elevations. Dewpoints will dip into the 50s keeping the
humidity on the lower side.

A frontal system approaches from the west Sunday night with a mild
night in store. Sct showers/tstms may reach the NW mtns around
sunrise, with main front crossing the region Monday. Could see one
area of scattered precip slip through followed by a second line
later in the day with passage of the cold front. Lapse rates high
enough that SPC has placed us in a Marginal Risk for severe on
Monday, with primary threat being a few marginally severe wind
gusts.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Started forecast using the ER Superblend of models for the
forecast grids and then tweaked the pops and clouds looking at the
12z runs and neighboring forecasts.

Cold front moves east through PA on monday night into Tuesday. A
secondary shortwave rotates around the upper level trough helping
to kick the front to the coast. Scattered showers and
thunderstorms will be sparked by the front and then by the short-
wave. Showers will begin to diminish from west to east by Tuesday
evening toward midnight and overnight.

With the upper level trough axis still to our west on Wednesday
and some cyclonic flow, there will be daytime development of
stratocu and maybe an afternoon shower. daytime temperatures will
be cool for late June with highs in the 70s through most of
Central PA with lower 80s in the Lower Susquehanna Valley. As the
sun lowers and temps cool, the strato cu will begin to dissipate
with mostly clear skies overnight Wednesday night.

We are currently forecasting Thursday to be dry however the GFS is
indicating an inverted trough on the spine of the Appalachians to
our south with the possibility of isolated showers or
thunderstorms popping on the mountains. The ECMWF does not have
this. The GFS continues to be more aggressive developing this
surface trough along the Appalachians and bringing the chance of
showers and thunderstorms northward into PA on Friday. Both the
GFS and the ECMWF have PA in the longwave trough through this
period and by late Friday have another shortwave dropping
southeast out of Canada kicking off afternoon convection on
Saturday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
High pressure over Pennsylvania will provide the region with
widespread VFR conditions and light wind through Sunday, with
just a chance of some minor vis reductions from fog arnd sunrise
Sunday.

OUTLOOK...

Mon...Sct tsra impacts, mainly west midday and east toward
evening.

Tue...AM fog possible. Isold PM tsra impacts possible.

Wed-Thu...No sig wx expected.

&&

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

&&

$$
SYNOPSIS...La Corte/RXR
NEAR TERM...DeVoir/RXR
SHORT TERM...La Corte/RXR
LONG TERM...Watson
AVIATION...Fitzgerald/RXR



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