385
FXUS61 KPBZ 271509
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1109 AM EDT Sat Apr 27 2024

.SYNOPSIS...
Above normal temperature is expected through much of the
upcoming week while precipitation will be periodic but mainly
focused on Tuesday and the later half of the week.

&&

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

- Low probability showers and thunderstorms are possible this
  afternoon.
- Warmer temperatures today.

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The main convective line will shortly exit east of the region
ahead of a mid-level shortwave trough, with the surface warm
front lifting northeast shortly after precipitation ends.

Strong warm advection is expected behind the warm front as
height rises begin aloft, while sun will periodic peak out
amidst area cloud cover. Hi-res models have become more bullish
on low probability showers and thunderstorms developing between
4pm-8pm across the region before ridging develops overhead; sfc
heating and residual boundary layer moisture may allow for a
few hour window of 200-500 J/KG CAPE and ~30kts shear in
conjunction with residual jet-aided ascent may be enough to
create isolated convection. No severe threat is anticipated.

The overnight period will be primarily dry and warm as the gulf
coast airmass settles into the region and ridge sets up
overhead. The exception is for northwest PA where embedded
shortwaves may traverses the ridge axis and provide enough
ascent along the nearby warm front to produce nocturnal
convection.


&&

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


- Summer-like temperatures Sunday and Monday.
- Storms Sunday are possible north of I-80.

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Rising 500mb heights are expected again on Sunday as a large
dome of high pressure builds over the eastern CONUS. A weak
shortwave will try and sneak over top of the ridge Sunday
afternoon. This will stall the ridge amplification and could
spark a shower or storm mainly over the I-80 corridor. This
upper level wave will likely bring an increase in clouds across
the northern half of W PA as well, while the rest of the
forecast area should see plenty of sun. A destabilization of
the atmosphere is possible Sunday afternoon with the greatest
across the north. Storm generation will be working against warm
air aloft and increased subsidence from the impressive ridge.
The ridge will also work to limit wind shear on Sunday,
hampering storm intensification.

The big story Sunday will be the well above normal temperatures.
Highs Sunday will push into the 80s across much of the region,
except the far north where cloud cover should keep temperatures
a bit cooler.

Upper level ridging will continue on Monday. The ridge will
shift southeastward Monday afternoon as a deep trough digs into
the western Great Lakes. However, strong subsidence from the
ridge should allow for a dry day with plenty of sunshine and
even warmer temperatures.

&&

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

- An unsettled pattern continues through next week with above-
  average temperatures favored.

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A surface cold front is expected to pass during the day on
Tuesday, followed by a flattening of the eastern ridge. By
Wednesday, clusters still vaguely agree on quasi-zonal flow, but
uncertainty spurs from here into late week. Mainly, two
scenarios emerge: the first develops a central CONUS ridge that
enforces an eastern troughing pattern. This would lead to a
drier, cooler pattern. The second scenario keeps quasi-zonal
flow in the central CONUS, which translates to zonal flow to the
east as well. This pattern may lean a bit warmer and more
unsettled.

Both CIPS analogs and the CSU MLP highlight low severe
probabilities into Tuesday through Thursday, so conditions will
need to be monitored as we head into next week.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
Showers and a few rumbles of thunder expected this morning with
a crossing warm front, but VFR cigs will likely be maintained
based off latest forecast soundings and upstream obs.
MVFR cigs will be possible tonight as the warm front stalls and
low level moisture pools along it. SE wind around 10 kt should
veer to the south after FROPA, with speeds continuing around
10kt.

.Outlook...
Mainly VFR is expected through Monday as a ridge builds back
across the region.

Restrictions are likely Tuesday in showers and a few
thunderstorms with a crossing cold front. VFR returns Wednesday
under high pressure.

&&

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

&&

$$

SYNOPSIS...Frazier
NEAR TERM...Frazier
SHORT TERM...22
LONG TERM...Milcarek
AVIATION...88