Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 161413

Area Forecast Discussion
National Weather Service State College PA
1013 AM EDT Sun Jun 16 2019

An unsettled and stormy weather pattern is expected across
central Pennsylvania this week. There will be multiple rounds
of heavy downpours with the potential for localized flooding
and isolated severe storms. Temperatures and humidity levels are
forecast to remain near average for mid to late June.


Humidity continues to creep upwards across the area today in
broad south-southwesterly flow. A low-amplitude shortwave
trough will push eastward from the Ohio Valley across PA this
afternoon/evening, and high-res model guidance develops
scattered t-storms along and south of a nearly-stationary
frontal boundary near the I-80 corridor.

SPC has painted the southern tier of PA under a SLGT risk for
severe storms capable of producing localized damaging winds and
hail. Heavy downpours will accompany any storms as well, with an
isolated flash flood threat mainly over areas of lowest FFG in
southwest PA.

Showers will likely linger into early tonight with fading
coverage and intensity after midnight.


Convectively active period continues into early next week. The
majority of model guidance is targeting south-central/southern
PA with the greatest risk of isolated/scattered severe storms
and potential flash flooding.

The pattern remains largely unchanged (slight southward shift
with time?) as series of small shortwave troughs/vort maxes
shift downstream from the OH Valley into a moist/unstable
airmass residing to the south of an elongated stationary front.
Confidence in the axis of heaviest QPF is lower than average,
as it is very dependent on the placement of the main frontal
boundary and any additional mesoscale boundaries established
from preceding convective complexes. The general trend is for
excessive rain and severe weather risk/threat areas to shift
southward from Monday into Tuesday but remain focused over the
southern 1/2 to 1/3 of the area. Model spread in the QPF is
also contributing to lower confidence, but there are plenty of
ingredients to support rounds of heavy rain and isolated to
scattered flash flooding. Like on day 1, SPC increased risk
level to slight on Monday over virtually the same area and
introduced a marginal risk along the southern tier on Tuesday.


Models hint at a drier period toward the end of the week into
first half of the weekend, which translates to just isolated
showers focused on the NW half. But precip chances increase
again with another storm system by Sunday.

Though elevated dewpoints will keep muggy conditions in place
with above average low temps, highs will top out a bit below
normal each day.


For the 12Z TAF package, a few more adjustments.

Area of showers to the north and west continues to

More in the way of convection across the Ohio Valley is
looking more and more like it will stay south of our TAF sites.

Earlier discussion below.

More in the way of showers and storms later today, mainly
southern PA, if not further south. This based on current
radar trends.


Mon...AM low cigs/fog poss N and W Mtns. Scattered PM tsra
poss, mainly south.

Tue...AM low cigs/fog possible. Scattered PM tsra impacts
possible south.

Wed...Patchy AM fog possible. Isold PM tsra impacts possible
western half of Pa.

Thu...AM rain/low cigs possible. Scattered PM tsra impacts


Astronomical summer (solstice) begins Friday, June 21st at
1154AM EDT (1554 UTC).




NEAR TERM...Steinbugl/Evanego
SHORT TERM...Steinbugl
LONG TERM...RXR/Steinbugl
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