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342
FXUS61 KPBZ 101357
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
957 AM EDT Fri May 10 2024

.SYNOPSIS...
A lingering disturbance will keep showers over the area today. Cooler
conditions are anticipated over the weekend with a shift in the
synoptic pattern from the northwest.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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KEY MESSAGES:

- Showers chances continue into today.
- High temperatures 5-7 degrees below normal.
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Scattered light showers continue this morning aided by an
inverted trough extending out from a surface low across
Delmarva, exit region jet dynamics, and weak shortwave energy
traversing an upper trough across the Northeast. Low and mid
level drier air is noted on water vapor satellite intruding
into northern Ohio and will continue to slowly advect in as mid
level flow backs more west of north through the afternoon.
Latest hi res ensemble timing indicates the mid afternoon hours
(after 3pm) as the most likely time for rain chances to begin to
diminish, though it may be as early as 1pm if dry air advances a
bit quicker.

Probability of higher rainfall amounts (0.25 inches to 0.45
inches) will generally be focused east and southeast of
Pittsburgh due to orographic lift. Elsewhere, showers will only
amount to less than quarter of an inch. Temperatures today will
be a good 5 to 7 degrees below normal.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
KEY MESSAGES:

- Below average temperatures are expected with northerly flow.
- Thunderstorms chances return Saturday afternoon.
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Ridging over eastern Ohio Friday night into early Saturday is
expected to decrease precipitation. Temperatures will remain
cooler than average under northerly flow.

By late morning Saturday, a new fast moving shortwave dives
southeast from the Great Lakes and returns showers and isolated
thunderstorms to the region. While a few storms could be
considered strong, the still cooler conditions will only yield
MUCAPE values between 400J/kg to 600J/kg. The trough is expected
to slow and hang up as the surface low center crosses upstate NY
and become impeded by ridging to the east. This will serve to
keep precip over the area through the day on Saturday and even
Saturday night. Temperatures are still expected to be 5 to 7
degrees below normal through the upcoming weekend.

&&

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

- Cooler temperatures arrive by late week with highs in the 60s
  this weekend.
- Rain and thunderstorms are expected to return
  Tuesday/Wednesday.
- Severe storm potential remains low.
-------------------------------------------------------------------

A few light showers may remain along the ridge line early Sunday
as a trough exits east. Otherwise, dry and quiet weather return
for a majority of the day with building high pressure.
Temperatures will be near or slightly below average, depending
on have fast the clouds clear from the west.

Warmer than average temperatures Monday and will continue into
Wednesday as a slow moving low ejects out of the Great Plains
and reinforces southwest flow. As high pressure breaks down off
the Mid-Atlantic, showers and thunderstorms chances increase
Tuesday and Wednesday.

The Day 7 forecast sets the stage for much inconsistency as
plenty of ensemble members provide a diurnal trend to the precip
chances. Some setup high pressure and dry conditions for
Thursday next week. The NBM keep afternoon maxima of pops but
will keep the low chance probability. Long range models at the
moment project a low probability of severe storms given weak
shear and instability.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
Light rain showers, increasing in coverage this afternoon, and a
mix of MVFR/IFR cigs are expected for most terminals (save ZZV)
to start the TAF period. Intrusion of drier air as low pressure
exits east will erode showers and lift cigs during the afternoon
to early evening hours to VFR heights.

The combination of residual boundary layer moisture, some cig
deck clearing, and light wind may promote fog formation during
the pre-dawn hours Saturday morning. Highest probabilities are
along the higher terrain east/southeast of KPIT where daytime
showers will linger longest and drier air will be late on
arrival.


.Outlook...
Additional restrictions, along with showers and low probability
thunderstorms, will overspread the region again Saturday into
part of Saturday night with a crossing cold front. VFR returns
Sunday and Monday under high pressure, before low pressure
returns restriction potential on Tuesday.

&&

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

&&

$$

SYNOPSIS...Shallenberger
NEAR TERM...MLB/Shallenberger
SHORT TERM...Shallenberger
LONG TERM...Hefferan/Shallenberger
AVIATION...Frazier