-- Discussion containing changed information from previous version are highlighted. --
106
FXUS61 KPBZ 300126
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
926 PM EDT Mon Apr 29 2024

.SYNOPSIS...
Rain chances increase early Tuesday morning with an approaching
trough. Above average temperatures will continue overnight and
into Tuesday afternoon under southwest flow.

&&

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

- Dry, quiet weather is expected through midnight under high
  pressure.
- Precipitation chances increase early Tuesday with an
  approaching trough from the west.
- Near record high min temperature Tuesday morning is possible.
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6:30pm update: No major changes have been made to the forecast
period. A new record high temperature was set at DuBois, PA
(82F), this breaks the old record 80F set in 1970.

Previous Discussion:

Eastern CONUS ridge will remain positioned just off the east
coast and residing over the region today as an upper level low
lifts toward the western Great Lakes. Warm air aloft and
subsidence will cap any convection, keeping dry conditions in
place and allowing for plenty of sunshine. Near to record high
temperatures are possible at all climate sites.

Ridge axis will shift eastward tonight and Tuesday as a
shortwave trough will push the dome of high pressure toward the
east coast. An increase in cirrus clouds tonight should keep
overnight lows warm. Near to record high minimum temperature at
most climate sites could result. This could also be a case where
early convection arrives late tonight in some of the
northwestern or western counties. This will of course impact the
low temperatures across the region as well.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
KEY MESSAGES:

- Showers and thunderstorms return Tuesday.

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Upper level trough will weaken as it slowly crosses the region
on Tuesday. This loss in amplitude will result in a slower
crossing of a weak surface cold front. Shortwave trough movement
will dictate rainfall timing with the trends continuing to slow
the progression of the showers. This would result in rainfall
chances continuing into Tuesday night. Any severe threat will
depend on strength of that passing shortwave. It still appears
that the severe threat will be limited given excessive cloud
cover and residual warm air aloft. Thus the main concern for
missing parameters will be the lack of instability but plenty of
shear present. Thus is not out of the question to get a gusty
shower for Tuesday afternoon. However, the DCAPE values will be
a bit lacking with values around 500 J/Kg making the downburst
potential really lacking.

Height rises are likely to return on Wednesday, promoting dry
conditions and well above normal temperatures. It is certainly
not out of the question to still be dealing with a few showers
exiting the forecast area on Wednesday morning but overall, a
warm and dry forecast is on tap.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
KEY MESSAGES:

- An unsettled pattern continues through the long term with
  above-average temperatures favored.

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High pressure will provide well above normal temperatures and
dry conditions through Thursday night. Ensembles favor upper
level trough movement through the Great Lakes region Friday into
the weekend that would push the ridge axis southeast and
introduce widespread shower and thunderstorm chances. Timing of
said pattern shift (which will play role in precipitation timing
and temperature trends Friday into Saturday).

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
VFR will prevail through most of the overnight. Increasing
mid/high clouds are expected overnight in advance of a trough
with MVFR ceilings expected to spread across the area by 12z.
Showers will follow Tuesday morning and afternoon, and scattered
thunderstorms are possible in the afternoon with the crossing
cold front. For now, have kept PROB30 -TSRA groups for mainly
PIT eastward where probability is highest.

Light southerly winds overnight will veer more westerly through
Tuesday.



.Outlook...
VFR will return early Wednesday and Thursday under high
pressure.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...Shallenberger
LONG TERM...Shallenberger
AVIATION...Rackley/88