489
FXUS61 KPBZ 241953
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
353 PM EDT Mon Jun 24 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 TUESDAY MORNING/...
KEY MESSAGES:

- Quiet with light winds under high pressure tonight.

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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 TUESDAY 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 /20Z MONDAY THROUGH SATURDAY/...
High probability of VFR under the influence of high pressure
through the TAF period. Diurnal heating/mixing will yield mostly
scattered 5-8kft CU and northwest wind gusts to 20kts this
afternoon.

Calm, clear sky may foster localized river valley fog Tuesday
morning, but dry air should keep probabilities more confined
south of KPIT.

The biggest uncertainty lays in the potential movement of a MCS
(storm system) through the Great Lakes region overnight into
Tuesday. Though the favored path is west of the region, there
remains a low probability for decaying showers and thunderstorms
to enter eastern OH to western PA between 15-20z Tuesday.
Probability of occurrence remains too low for TAF mention at
this time.

.Outlook...
Assuming westward MCS path, VFR is likely into Tuesday night
before a weak shortwave trough fosters showers and thunderstorms
(with associated restrictions) Wednesday into Thursday morning.

High confidence in VFR under the influence of high pressure
Thursday into Saturday morning before the next low pressure
system passes.

&&

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

&&

$$

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