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687
FXUS61 KPBZ 240204 AAA
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
1004 PM EDT Sun Jun 23 2024

.SYNOPSIS...
Showers and thunderstorms will gradually end tonight after the
passage of a cold front. Temperatures drop to near normal on
Monday before increasing, yet again, next week.

&&

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

- Thunderstorms ending tonight
- Cooler temperatures tonight.
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Update...
Expired the Severe Thunderstorm Watch on time as the severe
weather potential continues to wane with diminishing shear and
instability.

Previous...
The latest mesoanalysis indicates the surface cold front is
crossing southwestern PA through SE OH. Continue to clear
counties from the Severe Thunderstorm Watch as the front and
line of storms moves through. ML CAPE is still 1500-2000 j/kg
south of the front, though this should be waning as the front
exits the area over the next few hours.

The severe weather potential is also expected to end by watch
expiration, as conditions become less favorable south of the
front. 0-6km shear values are trending downward, currently near
30kt south of the front. An exiting low level jet will also
contribute to lowering these values. Overall, a low potential
remains for a damaging wind gust in the watch area over the next
hour or so.

Mainly dry weather is expected for the rest of the night after
FROPA, as surface high pressure builds in under an approaching
upper trough.
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&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
KEY MESSAGES:

- Mainly dry weather returns
- Seasonable temperatures return Monday, warmer Tuesday.

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The upper trough will cross the NE CONUS Monday, as surface high
pressure builds in underneath. This should result in dry and
seasonable weather. Mainly clear skies and light wind should
result in radiational cooling Monday night. Most locations will
see lows in the 50s. Patchy river valley fog is also expected.

Rising 1000-500mb heights and warm advection should return
temperatures to above seasonable levels on Tuesday. A couple of
MCSs are expected to develop across the Midwest region Tuesday
night. Some operational models brush these complexes near the
Upper Ohio Valley region late Tuesday and Tuesday night. Given
the placement of the low level jet upstream, and the tendency
for MCSs to follow the 1000-500mb thickness pattern. As the 12Z
mesoscale guidance begins to come in, it has been a bit more
bullish on convective development in central Michigan. Its also
suggests that convective elements deteriorate as they head
southeast into ridging and drier air, but it will warrant
watching Tuesday and Tuesday night.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
KEY MESSAGES:

- Thunderstorms likely with a Wednesday cold front
- Cooler Thursday, followed by a warming trend
- Dry Thursday and Friday, before another front approaches
  Saturday
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The next shortwave trough, and associated surface cold front, is
expected to approach and cross the region on Wednesday, with
showers and thunderstorms likely. Strong to severe storms will
be possible, if current model projections of shear and
instability levels verify. This will also largely depend on a
favorable arrival time.

High pressure is expected to return dry weather to the region
Thursday and Friday. Seasonable temperatures are expected
Thursday, before a return to above average readings on Friday as
heights rise and warm advection occurs.

The next approaching cold front will return shower and
thunderstorm chances back to the forecast at the start of the
weekend.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Scattered to numerous showers and thunderstorms are expected
along and ahead of an advancing cold front this afternoon and
evening (favoring 19z-00z). Storm strength may be dependent on
degree of surface heating, but risks exist for damaging wind and
small hail along with the typical vsby/cig restrictions in
heavier rain.

Isolated showers may persist after FROPA this evening given
delayed passage of the upper level trough axis. However, its
crossing overnight will foster cool, dry advection that will end
shower activity and begin to erode post-frontal stratocu.
Ensemble models vary in degree/timing/cover of that clearing,
with residual boundary layer moisture favoring pockets of low
VFR to MVFR cigs near FKL/DUJ/LBE/MGW.

Building high pressure will support VFR and reduced afternoon CU
Monday. Expect deeper mixing and residual surface gradients to
foster 20-30kt NW afternoon wind gusts.

.Outlook...
Ensembles hint at potential MCS moving SE out of the Great
Lakes sometime between Tuesday night through Thursday morning
ahead of the next upper level shortwave. This is will need to be
monitored for terminal impacts.

Thereafter, high pressure and ridging aloft should support
multiple days of dry weather.

&&

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

&&

$$

SYNOPSIS...WM/Milcarek
NEAR TERM...WM
SHORT TERM...WM/Milcarek
LONG TERM...WM/Milcarek
AVIATION...Frazier