Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 162000

Area Forecast Discussion
National Weather Service State College PA
400 PM EDT Wed Aug 16 2017

A warm front will push up from the south on Thursday and a cold
front will move through the state on Friday bringing a few
rounds of showers and Thunderstorms. High pressure will clear
things out behind the front for the weekend.


High pressure firmly in control. Just some cumulus congestus
over the NE counties and over WV. Warm front over OH is the site
of a few SHRA but those should stay mainly to the W/s of the CWA
before dying off with loss of heating. An unmentionable threat
of precip is on order for the Laurels and far far eastern zones
through sunset because the bases are high and cloud depth

Light wind and still-summer dewpoints will keep the threat of
fog coming back again tonight - but mainly in the river
valleys. Have mentioned fog , but it should not be as bad as
last night/this morning with dewpoints dipping here a little
this afternoon. Clouds may start to flow over the CWA from SW-NE
late tonight, but no rain threat.


Large scale forcing starts to increase over the Midwest on
Thursday, and the warm front should lift into at least srn PA
during the daytime on Thursday. Afternoon maxes may be kept a
little lower than today, but will keep them highly similar due
to slightly milder temps in the morning and the start of a light
southerly wind during the day. POPs for Thurs aftn will be
brought up just a shade as many models are cranking out
convective QPF in the aftn in the SE and NW. The central and NE
zones may stay dry through sunset, but will still mention a low
chc POP there since the ridge will crest overhead before sunset
and upstream convection may drift into the area late.


The progression of a warm front north-eastward will be the best
indicator for showers and thunderstorms, with them most likely
Thursday night into Friday. A cold front out ahead of a
strengthening closed mid level low will push through Friday
afternoon and evening. Combined with moisture out ahead of this
system the ensembles and models are in decent agreement on
timing and progression bringing it through the mid Atlantic
Friday night into Saturday morning. SPC guidance for Friday
places much of the area in a marginal risk for severe
convection. There could be some severe convection later Thursday
night with CAPE remaining high through the night. However, the
amount/placement of forcing will be the question that period.
Timing of the cold frontal passage is fairly early in the day
over the west, but most of the area will be quite unstable on
Friday afternoon and lingering into the evening in the SE. High
pressure moves back in for Saturday.

Based on NBM and latest mid range guidance have trended
temperatures upward through the weekend and into next week.


VFR into early tonight with high pressure and large-scale
subsidence overhead. Fog impacts are expected again late
tonight into Thursday morning after which much of the day on
Thursday should be VFR. Scattered showers will pop up Thursday
afternoon in the west and south and move northeastward. The
coverage of these showers before 18Z is too low to even mention
PROB30s for any site in this package. However, Thursday
afternoon into Friday evening hold a much more widespread
chance of thunderstorm impacts as a warm front lifts across the
area and a cold front follows 24 hours later.


Thurs night-Fri...SCT-NMRS TSRA impacts likely.

Sat-Mon...No sig wx.




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