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013
FXUS61 KPBZ 090111
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
911 PM EDT Wed May 8 2024

.SYNOPSIS...
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Showers and thunderstorms will return, mainly south of
Pittsburgh, as a frontal boundary turns around and approaches as
a warm front. Thereafter, unsettled weather continues, with
periodic showers and storms Thursday through Saturday.
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&&

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

- A returning frontal boundary will provide shower and
  thunderstorm chances late tonight, mainly south of Pittsburgh.

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A frontal boundary positioned south of our region will begin to
lift back north as a warm front overnight as 500mb heights begin
to rise. Clouds will increase as a result, with contribution of
high clouds from convection well to the south. With lift
supplied by the front and a shot of isentropic lift, showers and
thunderstorms will begin to fire in the southern CWA after 06Z,
with chances greatest near and south of the Mason-Dixon Line.

At this time, feel that the threat of severe thunderstorms
overnight is low. Shear appears to be weak overall, and storms
are likely to be elevated. DCAPE appears marginal for a
downburst threat, but perhaps some hail could be realized from
the stronger storms given elevated CAPE.

Overnight low temperatures will end up some 5 to 10 degrees
above normal, given the cloud increase.
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&&

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

- Showers/storms return early Thursday through Friday.

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A sfc low approaching from the west will track along a boundary
in the vicinity of the Mason- Dixon line on Thursday, followed
by a shortwave on Friday. Another Marginal risk for flooding
seems to be the case. This will depend on where the main axis of
moisture sets up. Hi res models suggest this may be a bit
further south than the Tuesday night activity and may be less
impactful. NBM probs in DESI do surpass 40% for 1 inch for the
area south of the Mason Dixon. Thus, any flooding issues will be
dependent on training in WV or any heavier rainfall over the OH
and PA areas that received heavy rainfall already. Strong
height falls on Friday usher in a cooler pattern with a long
wave trough position in the east.

&&

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

- Ensembles suggest a wet pattern into the weekend.
- Cooler temperatures arrive by late week with highs in the 60s
  this weekend.
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By Friday night into Saturday, another fast moving shortwave
dives southeast in northwest flow bringing another round of
showers to the area. Overall, a rather damp weekend is on tap.
The slow moving trough will keep rain chances through Sunday as
well.

Temperatures through Sunday will be 5-10 degrees below
the seasonal normal of about 70 this time of year.

Some moderation of temperatures is likely Monday and Tuesday as
heights rise and flow turns from northwest to more westerly,
though there is a possibility of another trough dropping over
the northeast on Tuesday keeping things a bit cooler than
currently forecast.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
VFR is expected to continue through at least 12Z before a low
pressure system track through the region and restrictions
showers and thunderstorms.

MVFR clouds and MVFR/IFR vis from convection are expected to be
in the vicinity of multiple TAF sites. Probability of thunder is
expected to increase after 16Z with diurnal heating and the
center of the low entering eastern Ohio. A few storms south of
PIT may be severe at times.

The potential for IFR to LIFR conditions increases late Friday
night under moist, cool conditions with a cold front.

.Outlook...
Restrictions will likely continue through Friday afternoon with
lingering low-level moisture and cold advection from the
northeast.

&&

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

&&

$$

SYNOPSIS...CL
NEAR TERM...CL
SHORT TERM...Shallenberger/88
LONG TERM...Shallenberger
AVIATION...Hefferan/88