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280
FXUS61 KPBZ 121708
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
108 PM EDT Sun May 12 2024

.SYNOPSIS...
High pressure will move into the area today with lingering
showers ending this morning and sunshine increasing this
afternoon. Southerly flow will bring dry and much warmer
conditions on Monday with temperatures warming about 10 degrees
above normal. Low pressure moving up the Ohio Valley Tuesday and
Wednesday will bring showers and thunderstorms.

&&

.NEAR TERM /THROUGH TONIGHT/...
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KEY MESSAGES:

- Showers ending today
- Clearing trend later today and tonight
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The latest upper air analysis shows a vertically stacked low
across the Lower Great Lakes region that is moving toward the
East Coast while high pressure/ridging build from west. A
cloud clearing trend should continue from W-E today, though the
additional heating will produce scattered to broken cumulus
clouds as low convective temperatures are in place. Mainly clear
skies are expected by this evening as the ridge builds across
the region. Warm advection aloft should result in a few mid
level clouds increasing, especially later tonight.
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&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
KEY MESSAGES:

- Dry weather likely with lower humidity
- Sunshine will bring temperatures close to 80F
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An upper low is expected to move slowly across Kansas and into
Missouri during the period. Downstream short wave ridging will
build 500 mb heights into the lower 5700s and promote sunshine.
850 mb temperatures will warm into the 12-14C range, with
temperatures likely to be up around 80F in the southern half of
forecast area. Continued to bump NBM first guess up 2F as
sunshine and deep mixing to 7,000 feet in the boundary layer
suggest it will have the usual cold bias for MaxT.

There is a low probability of showers north of I-80 in warm
advection regime but this is more likely north of forecast area.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
KEY MESSAGES:

- Midweek showers and thunderstorms likely, with limited severe
  and flooding threats.
- Dry conditions likely on Thursday
- Ensemble spread is high Friday and Saturday, but another
  trough appears to bring shower chances
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Upper trough expected to move across southern IL Tuesday and
then along IN/KY border Tuesday night. This feature then
progresses across southern Ohio and northern West Virginia
Wednesday and Wednesday night.

Warm and moist advection will push precipitable water values up
around 1.35" by Tuesday afternoon and support showers and
thunderstorms. Lingering showers on Wednesday in weak
deformation zone northeast of the upper low are expected to keep
the wet weather going a second day.

NBM 48 hour Probabilities of exceeding 1" of rainfall range
from about 30% in the northwest portion of the forecast area to
about 50% over the ridges. However, 2" probabilities are less
than 10% and in many cases less than 5%. Instability will be
marginal and 500 mb flow quickly drops below 20 knots Tuesday,
so it appears that the probability of significant impacts for
convection are low.

Upper ridging appears likely for Thursday along with sunshine
and temperatures 75-80F.

Another trough with potential for showers and thunderstorms
appears to be on tap for Friday and Saturday, though
considerable standard deviation is noted in that period over the
Great Lakes area for the ensembles/NBM.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
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VFR expected through the TAF period, save for lingering lower
MVFR cu decks near FKL through 20z.  Erosion of stratocu from
the southwest to the northeast is expected through this evening
as high pressure builds in from the southwest.

Relocation of the surface high east Monday will promote
southerly wind while maintaining dry weather. Weak shortwave
movement north of the region btwn 10z-18z is unlikely to
generate precipitation (less than 20% probability) but may
foster some sct/bkn mid-level cloud decks.

.Outlook...
Restrictions are likely, along with showers and possible
thunderstorms, Tuesday through early Thursday as slow moving low
pressure crosses the region.

Another crossing low pressure system with precipitation and
restriction chances is becoming more likely for next weekend as
well.
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&&

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

&&

$$

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