-- Discussion containing changed information from previous version are highlighted. --
533
FXUS61 KPBZ 120515
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
115 AM EDT Sun May 12 2024

.SYNOPSIS...
Scattered rain showers likely through tonight with passage of a
cold front. Dry and more seasonable weather will develop
through Monday before the next round of upper level disturbances
increase precipitation chances midweek.

&&

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

- Scattered showers remain overnight
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The thunderstorm and severe weather potential has ended with the
passage of a cold front. An upper low across southern Ontario
and the Lower Great Lakes region will drop southeastward
overnight. This should maintain scattered showers across the
region. Lows will be near average for this time of the year.

&&

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

- Dry weather likely, saving for passing disturbances near far
  northwest PA.
- Above normal temperature likely by Monday.
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Shortwave ridging ahead of a deepening central CONUS upper
trough will promote dry weather and rising temperature through
Monday. Residual NW flow Sunday with the surface high just to
the west will limit the degree of temperature rebound. But as
heights further increase Monday and the surface high positions
along the eastern coast, warm advection in southwest flow will
drive temperature to about 5 degrees above the daily average.

Any precipitation chances during this period will be tied to
shortwave movement well to the north and the positioning of a
developing warm front near the region. Latest trends lift the
warm front and upper wave north of the region, but will
maintain low probability chances in northwest PA in case those
trends change.

&&

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

- Midweek showers and thunderstorms likely, with limited severe
  and flooding threats.
- Dry conditions likely to end the week.
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The sagging central plains trough will meander eastward across
the TN River Valley Tuesday into Wednesday, with weak shortwaves
likely traversing the Upper Ohio River Valley ahead of the wave.
Showers and thunderstorms are likely through the
afternoon/evening Tuesday, though positioning of forcing and
potential influence of shortwave ridging in the mid-Atlantic
could alter the areal coverage/probabilities. Early analysis
suggests that the instability/shear parameters are unlikely to
promote much severe threat, while forcing/deep moisture should
remain south of region and limit a flooding threat (only 20%
probability of seeing greater than 1" of rain over 24 hours at
any location).

The trough will progress towards the eastern coast Wednesday,
with low positioning and depth dictating how long precipitation
will linger in the Upper Ohio River Valley. Ensembles are
confident in ridging developing over the lower Ohio River
Valley late week that should promote a few day period of dry
weather and above normal temperature.

&&

.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
VFR conditions are expected to start for most airports. The
exception will be FKL and DUJ, where IFR cigs are expected with
low level moisture in place. Conditions should deteriorate to
MVFR for BVI-AGC-LBE and points north as an upper low drops
southeastward across the region through early Sunday morning.
Scattered showers are also expected with the passage of the low.
ZZV and MGW should have already, or will soon clear as drier air
moves in from the west.

Improvement to VFR is expected from west to east through the day
as the low exits, and high pressure builds in. A
cumulus/stratocumulus layer should also dissipate by evening,
with wind diminishing.

.Outlook...
VFR is expected through Monday night under a ridge of high
pressure. Restrictions are likely, along with showers and
possible thunderstorms, Tuesday through early Thursday as slow
moving low pressure crosses the region.
-- End Changed Discussion --

&&

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

&&

$$

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