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119
FXUS61 KPBZ 060212 AAA
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
1012 PM EDT Wed Jun 5 2024

.SYNOPSIS...
Showers and thunderstorms are expected tonight. Unsettled
weather will remain into the weekend. Cooler temperatures
return Friday and hold through the weekend.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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KEY MESSAGES:

- Showers and thunderstorms tonight with a crossing cold front
- Marginal potential for severe storms
- Locally heavy rain where training occurs
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1010 PM Update...
VAD wind profile from PBZ has shown some sharper veering in the
lower levels over the past hour. However, the latest meso
analysis shows instability has continued to slowly diminish. The
latest CAMs indicate the instability will continue to diminish
overnight. Recent radar scans indicate the rotation in the Knox
county storm has weakened, though we will monitor for any
further development. We will also continue to monitor for any
potential training of showers and storms overnight for
localized flooding.

845 PM Update...
The 00Z PIT sounding shows some veering in the wind profile
generally below 750 mb. The latest meso analysis shows some low
level rotation potential across central OH, where a storm in
Knox county has had rotation. We will monitor the trends as this
storm moves eastward.

8 PM Update...
The latest meso analysis was showing some decrease in ML CAPE
across the region, with values ranging from 1000-1500 j/kg.
Ascent will continue to increase from the west this evening
ahead of an approaching shortwave trough and its associated
surface cold front. Shear is expected to remain marginal
overnight, with 0-6km near 30kt. Instability is expected to
gradually wane, with a diminishing potential for severe storms
after midnight.

Moisture transport vectors indicate some increase in
precipitable water (to 1.8 inches) is expected late this evening
and overnight. There remains some potential for flooding,
especially where training of heavy rain would occur.

The surface cold front is expected to cross western PA toward
morning, with rain chances decreasing after FROPA.
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&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
KEY MESSAGES:

- Risk for scattered showers/storms continues on Thursday with
  the passage of a deep trough.
- Continued activity on Friday with cooler temperatures.

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Lingering showers/storms will end Thursday morning as the cold
front exits to the east. A deep shortwave trough is expected to
swing through Thursday afternoon. This will likely return
showers and storms Thursday afternoon/evening. Thursday
afternoon seems to be a period to watch for as well with MU CAPE
values between 500 and 700 J/Kg with nearing 50 knots of shear.
SPC has a general thunder this day but there certainly could be
a strong storm with this passing post frontal trough.

Just above-average highs expected Thursday.

Highly anomalous upper level low will move across the Great
Lakes on Friday. Waves of energy will swing around the low as
will much cooler air. This will keep our weather unsettled on
Friday. Temperatures should be noticeably cooler Friday with
plenty of clouds and scattered showers.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
KEY MESSAGES:

- Periodic showers with cooler conditions are expected through
  the weekend with a slowly crossing upper-level low.

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The upper-low will dig into New England Friday night into
Saturday. This will keep cooler and showery conditions in the
forecast as we head into the weekend and into early next week.
While there is low confidence on pinpointing the best timing of
these showers each day, ensembles do agree on the general
showery pattern with upper troughing persisting through the
weekend and possibly into early next week.

The pattern will change by Tuesday next week as the upper low
finally gets shunted to the east with riding finally moving back
into the region. This will mean dry weather possibly returning
for Tuesday and Wednesday next week as rain chances remain below
30%.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
The TAF period begins with VFR conditions and light rain
showers, excluding upslope IFR low ceilings at DUJ. However,
this will soon change, as a trough and an associated cold front
bring convection into the region during the late evening and
into the overnight hours. Have used two-hour TEMPO groups to try
to time the most likely arrival of thunderstorms at each
terminal. Confidence in thunder occurrence for terminals east of
PIT is lower than west, as the loss of diurnal heating may
reduce precipitation to showers; nevertheless, ceilings are
likely to drop through MVFR to IFR as the trough and front
cross. Other storm impacts could be variable wind gusts in the
30 to 40 knot range, as well as brief downpours creating
IFR/LIFR visibility for a short time.

Low ceilings will linger through sunrise at most terminals with
some patchy 4-6 mile mist, before improvement to VFR in daytime
mixing behind the front. Steep low-level lapse rates will likely
promote wind gusts in the 20 to 25 knot range by midday
areawide, with some modest instability creating isolated showers
as well.

.Outlook...
Periodic restrictions and scattered showers are expected
through Sunday as a slow moving upper low persists across the
Great Lakes region.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$

SYNOPSIS...Shallenberger
NEAR TERM...WM
SHORT TERM...22/Shallenberger
LONG TERM...22/Shallenberger
AVIATION...CL