Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 160545
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
145 AM EDT Tue Jul 16 2019

.SYNOPSIS...
---Mid Summer heat and humidity on the way---

Humidity will be on the increase through Thursday as the much
weakened remnants of what was once Hurricane Barry, migrates
slowly northeast out of the Mississippi and Ohio River Valleys.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Mid and high clouds starting to increase over far southwest PA
early this morning ahead of approaching warm front over the
Ohio Valley. Can`t completely rule out a shower toward dawn over
the western edge of the forecast area. However, convective
activity along front will be at a minimum as it moves into
western PA this morning.

Min temperatures should be several degrees milder than last
night due to an uptick in humidity, but not bad for July with
readings at dawn ranging from the upper 50s over the north, to
the mid 60s in the south. Based on output from latest
SREF/NAMNest, have added patchy late night valley fog to the
eastern counties, where pressure gradient will remain the
weakest.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
Higher dewpoint air will pour back in on Tuesday as a warm front
scoots through the region. Along with the humidity, the
chances for showers will be on the increase. Models develop a
fair amount of CAPE by afternoon as the warm front passes.
Blended MOS POPs show the first small chances for a shower in
the far western counties early in the morning, but the best
chance for thunderstorms will be from mid day onward, as PWATs
in excess of 1.75"/2-3 sigma accompany the warm front.

Lapse rates are not going to be especially high and wind shear
will be weak, so the threat for severe storms should be minimal.
However, local downpours producing spot 2+ inch amounts seem
possible in the tropical airmass.

A good deal of cloudiness should hold temperatures down across
the Allegheny Plateau, where maxes are likely to be in the low
80s. More sunshine further east could push readings to around
90F across the Susq Valley before late day convection forms.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
*Heavy downpours possible Wed-Thu with remnants of TC Barry
*Excessive heat risk Fri-Sat

Tropical moisture will stream into the region Late Tuesday into
Wednesday from the remnants of TC Barry. There continues to be
a marginal risk on Day 3 for excessive rainfall.

Model guidance continues to signal the potential for excessive
heat around the end of the week and into the weekend. Maximum
heat index values peak in the 100-105 range Friday and Saturday.
Heat headlines appear likely during this time and will continue
to highlight heat risk via HWO, social media and DSS briefings.

Very warm mid-level temperatures may act to limit/cap t-storms
Fri-Sun. That said, models hint at the potential for MCS
activity propagating along wavy frontal zone on the northern
periphery of summertime upper ridge/heat dome. Plenty of
uncertainty with exact timing and placement of pcpn so opted to
stay close to blended model guidance.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR prevailing most of Tuesday. Patchy fog is possible over the
eastern terminals around daybreak. Scattered thunderstorms may
result in brief airfield restrictions this afternoon and
evening. Shower activity is most likely to continue across the
far northwest airspace late tonight into Wednesday morning.

.Outlook...

Wed...Scattered to numerous showers/thunderstorms with heavy
downpours probable.

Thu-Sat...Isolated PM thunderstorms possible.

&&

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

&&

$$
SYNOPSIS...La Corte
NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...Fitzgerald/La Corte
LONG TERM...Ceru/Steinbugl
AVIATION...Steinbugl


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