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459
FXUS61 KPBZ 260022
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
822 PM EDT Sat May 25 2024

.SYNOPSIS...
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Thunderstorms should gradually diminish and end this evening
with areas of fog forming after midnight. 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 8 AM SUNDAY MORNING/...
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KEY MESSAGES:

- Thunderstorms continue to diminish this evening though locally
  heavy rain remains possible southern half.
- Widespread dense fog possible after midnight with light winds,
  clearing skies, and moist boundary layer from winds.
-------------------------------------------------------------------

Most of the activity has moved south of Pittsburgh and there are
clusters of thunderstorms from Preston County WV back to
southern Muskingum County OH. Locally heavy rainfall with
repeated rounds of storms and Precipitable Water values of
1.3-1.4" suggests potential for flash flooding until late
evening.

With light winds and widespread rain, expect dense fog to form
after midnight and may warrant a dense fog advisory for much of
area.
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&&

.SHORT TERM /8 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
KEY MESSAGES:

- High pressure returns dry, warm weather for Sunday
- Another round of potentially strong to severe thunderstorms
  Sunday night into early Monday morning, then Monday afternoon
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Flat upper ridging builds for Sunday 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%.

A warm front approaches late in the day on Sunday 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 Sunday
night may help maintain several stronger storms with damaging
wind and/or large hail into eastern Ohio. That said, a general
weakening trend is expected as these storms cross into our
region, and thus just the far western half of the area remains
outlined in a Marginal Risk (1/5).

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. 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.

&&

.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.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...

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Thunderstorms at KPIT and KMGW should end by 02z with other TAF
sites already seeing the threat end. Outside of thunderstorms
there are no restrictions to ceilings and visibilities.

With the rather widespread precipitation event (with exception
of ZZV) NBM/GLMP is bullish on dense fog formation at most TAF
sites with light winds and moist boundary layer. Visibility 1/4
mile expected from roughly 07z-13z. Rapid burnoff Sunday morning
will result in VFR returning thereafter and lasting well into
the night before late night thunderstorm threat returns.

.Outlook...
Thunderstorm probabilities are rather high Memorial Day as
another low pressure system moves through the Great Lakes. A
pattern shift thereafter will introduce periodic precipitation
chances and potential for more prolonged cig restrictions.
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&&

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

&&

$$

SYNOPSIS...Craven
NEAR TERM...Craven
SHORT TERM...MLB
LONG TERM...MLB
AVIATION...Craven