Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 240817
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
417 AM EDT Mon Jul 24 2017

.SYNOPSIS...
An upper trough, located over the Great Lakes early this
morning, will push slowly across Pennsylvania early this week.
In its wake, high pressure will build southeast across the
region by midweek. A cold front will likely push southeast
across the region next Friday.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
Radar trends at 0730Z showing back edge of steady rain beginning
to lift out of eastern Pa, as weak surface low over the Delmarva
Peninsula and associated southeasterly low level jet lift out.
Latest HRRR runs and upstream conditions suggest steady rain
over the northeast part of the forecast area will dwindle to
scattered showers toward dawn, then exit the area completely by
around 12Z. Earlier flooding concerns have diminished and
remaining stratiform rain over the northeast part of the
forecast area is not anticipated to cause more than minor
flooding early this morning.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TODAY/...
Upper trough over the Grt Lks is poised to swing into the
region later today, causing scattered convection to break out
along associated cold front as early as late morning over the
northwest mountains, and during the afternoon elsewhere.

After a cloudy start to the day in many locations, model
soundings indicate a fair amount of sunshine developing by
midday, as lower PWAT air filters in on westerly flow. NCAR
ensemble indicating prefrontal CAPEs rising to around 1000 J/KG
by afternoon across the eastern 2/3rds of the forecast area.
The combination of modest CAPEs and 0-6km shear of 40-45kts will
support a marginal threat of severe weather during the
afternoon. Convection-allowing models indicate scattered showers
will arrive across the northwest mountains by late this
morning, with more robust convection forming along cold front,
as it pushes through the rest of the forecast area during the
afternoon hours.

&&

.LONG TERM /TONIGHT THROUGH SUNDAY/...
Not a lot of change from yesterday. Still going mainly
with dry conditions Tuesday into Wed. Did lower temperatures
a degree or so on Tue, given concern for some clouds and
lack of real strong cool push. Also models show pair of weak
lows just inland from the south shore of the lower Great
Lakes, not sure what to make of this. A strange summer lately.

Still expecting showers and storms on Thursday into the first
part of Friday, with the next cold front.

Went with mainly dry conditions after early Friday.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
At 00Z the latest radar has showers and thunderstorms moving
through eastern PA bringing heavy rain. These are exiting the
region but will bring -SHRA with VCTS to IPT through 01Z. The
next line is approaching from the west along a boundary which
will reach JST with possible -TSRA between 02Z to 03Z. These
will slide along the southern tier of counties and have timed
them through the TAFs. Latest short term models are showing the
precipitation should exit the region between 09Z to 11Z. Expect
cigs and vsbys to drop to IFR and LIFR shortly after due to low
stratocu and valley fog.

The restrictions should lift between 12Z to 14Z. Another round
of showers and thunderstorms are possible tomorrow afternoon due
to another trough moving through the mid Atlantic. Expect
showers and thunderstorms west to east after 19Z.

Tonight, restrictions return in wake of trough axis, with IFR
conditions likely in the north and east, and MVFR in the central
mountains.

.OUTLOOK...

Tonight...Cig restrictions likely. Scattered TSRA/SHRA.

Mon...AM restrictions likely. Scattered TSRA.

Tue-Wed...AM restrictions north/west. Otherwise no sig wx.

Thu-Fri...Chance of afternoon TSRA/SHRA.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 6 AM EDT early this morning for PAZ006-
010>012-028-037-041-042-045-046-049>053-056>059-063>066.

&&

$$
SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...Martin
AVIATION...DeVoir/Ceru



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