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796
FXUS61 KPBZ 302347
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
747 PM EDT Tue Apr 30 2024

.SYNOPSIS...
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The remainder of the work week will be dry and warm. A slight
cool down is expected this weekend with returning rain
potential.
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&&

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

- Clouds will decrease through the night, with areas of fog possible
after midnight.
- Low temperatures several degrees above normal.

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Showers have almost completely departed the forecast area to the
east as a shortwave trough approaches the ridges, with an
accompanying cold frontal passage. The 00Z PBZ sounding shows a
cap in the 750-700mb layer that effectively prevented
convection from getting tall enough to reach the -10C level for
lightning generation.

Weak surface ridging will build into the region overnight, providing
subsidence which will erode most of the remaining cloud cover. With
drier dewpoints slow to arrive from the west, overnight low
temperatures will remain several degrees above climatology. The
lingering moisture, along with light wind, will raise the
possibility of patchy fog after midnight, particularly to the east
of Pittsburgh, where a bit more rain fell today.
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.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
KEY MESSAGES:

- Dry weather and above-normal temperatures expected Wednesday.

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Height rises and a return to southwest flow is expected on
Wednesday as temperatures push back into the 80s for most
locations. Clear skies and mixing into day air has led to a
slight upward adjustment in temperatures and downward
nudge in dew points. Nonetheless, fire weather concerns remain
low with light winds and humidity just above thresholds.

A weak front may move in later in the day into eastern Ohio,
but any convection will struggle in dry air. Dry conditions are
favored to continue. Dew points may recover slightly ahead of
the passage.

&&

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

- Warm and dry weather expected under high pressure on Thursday.
- An unsettled pattern returns Friday through the weekend with
  above-average temperatures and periods of showers and
  thunderstorms favored.

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High pressure will continue to support above-normal temps and
dry conditions through Thursday night. Ensemble guidance
indicates the best chance for Thursday afternoon highs to exceed
80 degrees occurs south of I-80 where widespread probabilities
are 70% or greater. Lower probabilities (<50%) exist along and
north of I-80, where temperatures are more likely to top out in
the upper 70s. Lows Thursday night similarly range from upper
50s south of I-80 to low 50s farther north.

Ensembles continue to favor upper level trough movement through
the Great Lakes region Friday into the weekend that would push
the ridge axis southeast and lead to a return of more active
weather. While this more active pattern certainly increases
chances for showers and thunderstorms, it also introduces
greater uncertainty and makes it more difficult to narrow down
details regarding exact timing and intensity. According to the
latest ensemble runs, Saturday appears to be the most likely day
for widespread rainfall, though chances really begin to ramp up
Friday afternoon and could linger straight through the weekend
and into next week. Stay tuned for more on this as we get closer
to the weekend.

As for temperatures, at this time Friday appears to be the
warmest day of the period with highs potentially reaching the
mid to upper 80s across much of the area. In fact, ensembles
already indicate a 70% or greater chance of areas south of I-80
exceeding 85 degrees. Temperatures Saturday through Monday also
trend above normal, but could remain in the 70s due to thicker
cloud cover and a greater coverage of showers and thunderstorms.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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Wind will shift to the northwest with frontal passage overnight
tonight as high pressure quickly builds. Hi-Res model guidance
suggests elevated probabilities for LBE, HLG, MGW, and ZZV
during the overnight period for fog. The highest probability for
IFR to LIFR vis is over MGW (59%). These elevated probabilities
are account for sufficient low-lvl moisture and a lingering
boundary. AGC and PIT may be impacted by fog, but confidence at
the moment is low.

VFR conditions are expected with diurnal heating and reinforced
ridging after 13Z for all sites on Wednesday.

.Outlook...
VFR conditions are expected to continue into Thursday under high
pressure.
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&&

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

&&

$$

SYNOPSIS...Milcarek
NEAR TERM...CL
SHORT TERM...Milcarek
LONG TERM...Cermak
AVIATION...Hefferan