811
FXUS61 KPBZ 250454
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1254 AM EDT Tue Jun 25 2024

.SYNOPSIS...
Dry and cooler weather is expected tonight under high pressure.
Showers and thunderstorms are possible Tuesday and especially
Wednesday as a slow moving front pushes into the Ohio Valley.

&&

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

- Quiet with light winds under high pressure tonight.

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Evening Update...
Little change needed to the forecast this evening as everything
remains on track. See the previous discussion below for more
details.

Previous Discussion...
500 mb heights have been rising about 70 meters today and
should rise another 40 meters tonight.

High pressure centered along the OH/IN border currently will
head across OH this evening and into PA after midnight. Cumulus
will rapidly dissipate by early evening with clear skies. Tds
are in the 50s, so lows in the 50s appear reasonable. Fog
development is likely in many of the river valleys but not
expected to be unusually impactful.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- Shower and thunderstorms chances return especially by
  Wednesday when severe storms are possible.

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WNW flow at 500 mb with heights in the lower 5800s is expected
with somewhat warmer temperatures and gradually rising Tds on
Tuesday. Have low confidence in thunderstorm chances as there is
poor agreement in the CAMS on how convection in MN area this
afternoon and tonight evolves. FV3 is northern outlier bringing
MCS across MI and eventually across Lake Erie into NE OH/NW PA
Tuesday afternoon. Other options range from a weakening system
falling apart to having everything sway well west as large cold
pool turns convection southward and cuts off moisture west of
Ohio. So will be at the mercy of convective scale cold pool
development and movement so details will be scarce except in the
6-12 hour range.

Trough pushes across Ohio River Valley with 60 meter height
falls expected Wednesday over the forecast area. 25th to 75th
percentile QPF for KPIT ranges from 0.25" to 1.00", and with
convection there will always be a rather large range so this
seams reasonable. And as noted for Tuesday, the Wednesday
convective setup will be modulated by the evolution of Tuesdays
convective cold pools.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
KEY MESSAGES:

- Dry weather Thursday through Friday
- Near normal temperatures Thursday, before a late week warmup
- Shower and thunderstorm chances return for the weekend
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Cold front pushes through Wednesday night with significant
cooling and drying at low levels across the Upper Ohio River
Valley on Thursday. So near normal temperatures and quiet
weather are expected.

Heights gradually rise about 60 meters each day Thursday through
Saturday, eventually reaching about 5920 meters by Saturday. 850
mb temps will be 12C Thursday, rising to about 18C Friday and
near 20C on Saturday. So a warming trend is expected and will
culminate in decent shot at showers and thunderstorms with a
cold pushing through by Saturday night.

Currently 30-50% chance of hitting at least 90F by Saturday over
the forecast area, with highest values in the central and
southern zones. 50-75th percentile QPF at KPIT is roughly 0.25
to 0.65" for Saturday.

Trough pushes by Sunday with ridge building in Monday. Odds
favor dry weather and near to slightly above normal
temperatures. At this point ensembles suggest an upper high
centered over lower MS river valley with hottest temperatures
well southwest of the forecast area.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR is expected through much of the TAF period, outside of some
early morning MVFR to IFR river valley fog.

A mesoscale convective system (MCS) was developing across the
Western Great Lakes region. This is initially expected to track
eastward overnight, before diving to the south following the
1000-500mb thickness pattern and theta e gradient. It appears
most of the thunderstorm activity should stay just west of the
area where the best instability is expected, though an increase
in mid and dense high level clouds is expected. There is some
potential the MCS could track further east and reach some Ohio
airports, though a rapid weakening in thunderstorms is expected
by that time. A few SW wind gusts up to 20 mph are expected
today with mixing.

Shower and thunderstorm chances increase late tonight with the
approach of the next shortwave trough and surface cold front.
For now, included a VCSH at the end of the PIT TAF with
uncertainty in how much precip development will occur
overnight.

.Outlook...
Restrictions are expected Wednesday with ocnl showers and
thunderstorms as a cold front crosses the region. VFR returns
Thursday and Friday under high pressure. Restriction, and
shower/thunderstorm potential returns Saturday with the approach
of a cold front.

&&

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

&&

$$

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