Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 162020
AFDCTP

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

.SYNOPSIS...
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.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
GOES-16 shows a nice fair weather cumulus afternoon. Light winds
and temperatures in the upper 70s to mid-80s. The cumulus will
dissipate this evening.

Pleasantly cool mid-August evening and overnight. Patchy fog
mainly near water bodies.

The moisture to our southwest should begin to spread higher
clouds over the southwest early Thursday morning.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...

The PW values come up fast Thursday morning and our dew points
will rise rapidly. It will be a warm humid data with increasing
clouds and an increased chance of showers and thunderstorms.

The GEFS is not very robust with the probability of rain until
late in the day and into the next period. Non-convective
allowing models tend to be too wet and these models all suggest
highest probability of showers is after 18Z. Well, it`s August.


&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
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.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
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.

.OUTLOOK...

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

Sat-Mon...No sig wx.

&&

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

&&

$$
SYNOPSIS...Dangelo
NEAR TERM...Grumm
SHORT TERM...Grumm/Dangelo
LONG TERM...Ceru/Gartner
AVIATION...Dangelo


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