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652
FXUS61 KPBZ 261414
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1014 AM EDT Sun May 26 2024

.SYNOPSIS...
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Sunday is expected to be mostly dry under high pressure, but
thunderstorms will returning Sunday night into Memorial Day. As
we flip the calendars to June, temperatures fall back to just
below normal.
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&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:

- High pressure returns dry, warm weather for today.
-------------------------------------------------------------------

Flat upper ridging builds for today as surface high pressure
arrives in the wake of the departing cold front. This will be
the best day of the holiday weekend with little noticeable
difference in the airmass behind the front as NBM probability
for >85F is 40-60% mainly from Pittsburgh south. It will feel on
the muggier side too with dew points in the low to mid 60s. The
only wrinkle will be increasing cloud coverage this afternoon
ahead of an approaching warm front that will bring showers and
thunderstorms across the area this evening.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
KEY MESSAGES:

- Another round of potentially strong to severe thunderstorms tonight
  into early Monday morning, then Monday afternoon
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A warm front approaches late in the evening as low pressure
ejects out of the Plains. Increasing moisture in developing
southwest flow aloft will overspread mid/upper level clouds by
evening. Latest guidance has continued the trend noted in the
last update with slightly slower progression and onset not until
late evening/overnight. While this timing is not typically
favorable for severe weather in our area, a strengthening
30-40kt low level jet across the area late tonight may help
maintain several stronger storms with damaging wind and/or large
hail into eastern Ohio. Thus, the western couple tiers of OH
counties in the forecast area have been upgraded to a slight
risk, (2 of 5) with the rest of the area in a Marginal risk (1
of 5).

Ensembles indicate only slight deviations from the mean in regard to
the depth of an upper trough and additional shortwave energy
traversing an upper low spinning across the Great Lakes through
Monday. Aided by daytime heating and slow passage of a cold front,
yet another round of strong to severe thunderstorms is possible with
our area again outlined in a Marginal Risk with just a few
eastern counties in a Slight risk. Machine learning comes a bit
more aggressive with an extension of severe probabilities back
into our area from the east, but one potential limiting factor
may be morning cloud cover as NBM spreads pin even 60-70%
coverage on the low end of the distribution. Highs Monday will
be thus be cooler than those over the weekend with mid 70s most
likely. The periodic chances of rainfall through the weekend may
lead to a greater flash flood threat with saturated soils across
the area.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
KEY MESSAGES:

- Periodic rain chances continue through midweek.
- Dry weather favored to close out the week.
- Temperatures fall back toward seasonal average.
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Upper level troughing plagues the area into mid week and rain
chances continue into next week, although coverage should be
scattered and mostly diurnally driven aside from a secondary cold
front crossing the region Tuesday. By Wednesday, ensemble
disagreement increases with the axis and strength of the upper
trough, but any flavor of solutions doesn`t kick it out of the
eastern CONUS until toward next weekend. Broad surface high pressure
should finally turn the area dry by late week while temperatures
fall back towards seasonal average with lows in the 40s not out of
the question come mid to late week as the cooler airmass settles in.
The dry change of weather is expected to last into the coming
weekend.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Widespread dense fog is ongoing to start the 12Z TAF period.
There is some indication in the latest obs that it is beginning
to dissipate, with PIT, HLG, and MGW seeing improvements in
their visibilities. Expect this trend to continue as the sun
rises and we see better heating and mixing, with widespread
improvement to VFR expected by mid morning.

Most of the day will be dry with generally light south to
southeast winds. A line of thunderstorms is expected to move
through the area this evening, reaching ZZV around 22Z, PIT
around 00Z, and FKL/DUJ around 02Z. Some storms along the line
could be strong to severe and capable of producing gusty,
erratic winds.

Scattered showers and perhaps a few thunderstorms will linger
overnight in the wake of the main line of convection, though
severe potential decreases. Fog and low stratus will settle
back in overnight, especially during the pre-dawn hours Monday
in areas that see the heaviest rain this evening/tonight.

.Outlook...
Restrictions will likely linger through Monday morning with
continued showers and thunderstorms, eventually lifting to VFR
Monday afternoon. Restrictions with precipitation are then
expected periodically through mid-week.

&&

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

&&

$$

SYNOPSIS...Craven/MLB/Shallenberger
NEAR TERM...Craven/MLB/Shallenberger
SHORT TERM...MLB/Shallenberger
LONG TERM...MLB/Shallenberger
AVIATION...Cermak/Rackley