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847
FXUS61 KPBZ 101708
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
108 PM 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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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.
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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 /17Z FRIDAY THROUGH TUESDAY/...
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Light rain showers, increasing in coverage between 18z-22z,
rising cig heights are expected through this evening. Intrusion
of drier air as low pressure exits east will erode showers and
cigs during the early evening hours, resulting in areawide VFR
conditions.

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 (KMGW/KLBE/KDUJ).

A cold front will approach from the NW at the end of the TAF
period, producing a swath of light rain showers with low
probability for thunder.

.Outlook...
Additional restrictions are likely in conjunction with the
mentioned showers and low probability thunderstorms above.
Scattered light rain showers will linger into Saturday night as
the upper trough axis crosses. VFR returns Sunday and Monday
under high pressure, before low pressure returns restriction and
precipitation potential on Tuesday.
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&&

.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