Sunrise 6:21 AM   Sunset 8:12 PM Moonrise 11:31 PM   Moonset 7:17 AM

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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.

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