Sunrise 6:24 AM   Sunset 8:16 PM Moonrise 12:00 AM   Moonset 8:15 AM

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FXUS61 KPBZ 280518 AFDPBZ

Area Forecast Discussion National Weather Service Pittsburgh PA 118 AM EDT Sun Apr 28 2024

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

NEAR TERM /THROUGH TODAY/
KEY MESSAGES:

- Another warm day. Temperatures 10 to 15 degrees above normal.
- Afternoon showers and storms possible north.

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Overnight period in good shape. Made some minor adjustments to PoPs. Ridge is working to amplify overnight, but ahead of these height rises, a shower may sneak across the far north overtop of the building ridges. Raised overnight lows as well. With continued warm air advection, increasing low-level southerly flow, and cloud cover, temperatures should not fall very much overnight. In fact, areas in the northeast that never broke out of the easterly flow should do so and see temperatures rise overnight.

Slow and steady 500mb height rises are anticipated today. The ridge amplification will be hindered by a weak shortwave trough that will cross Lake Erie and eventually upstate New York today.
This wave will pull moisture eastward with it and also provide some weak large scale ascension over the I-80 corridor throughout the day. Instability/buoyancy will increase across the entire region today. Most of the area will be capped by the warm air aloft and increased subsidence from the building ridge.
However, over the I-80 corridor there will be somewhat cooler air aloft and those locales will rest at the top of the ridge in zonal flow aloft. This would be the area to focus for any afternoon shower and storm activity. NBM prob thunder is close to 30% this afternoon across the far north with probs of measurable precipitation approaching 50%. Forecast soundings from the deterministic models are telling the same story with impressive instability, even at the surface, and no cap. The crossing wave may provide enough forcing to spark convection.
Shear values are weak, which would mean more popup convection rather than organized. If stronger storms do develop, a scenario where outflow boundaries create new storms could come to fruition. PoPs will be maintained over the I-80 corridor this afternoon.

Another warm day. Went with NBM 50th pct highs as highs yesterday outperformed the mean. Expect scattered cu to develop across much of the region today, with a thicker cu cover over the north.

SHORT TERM /TONIGHT THROUGH TUESDAY/
KEY MESSAGES:

- Near record high max temperature Monday and high min temperature Tuesday are each possible.
- Diurnally driven isolated convection confined to northwest PA.

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Impressive eastern CONUS ridge continues to hold strong on Monday. Any available upper level energy will be kept at bay well to the west of the region or north of the peak of the ridge. Drier air will fill into the ridge on Monday and warm air advection will continue. Expect plenty of sunshine Monday with warmer temperatures. An isolated afternoon storm cannot be ruled out across the far north Monday, but with increased warm air aloft, and little forcing, initiation will be difficult.

Highs Monday will approach record levels at all climate sites.
NBM 75th pct for max T on Monday would break or tie the record high at 3 of the 5 climate sites. The key will be sunshine, and the possible decrease of surface dewpoints. Even if we don't reach the records, temperatures will be 15 to 20 degrees above normal.

The Central Plains trough will lift northward through the western Great Lakes late Monday, with a shortwave rounding its based expected to move eastward through the Upper Ohio River Valley Tuesday. This movement will push a weak surface cold front eastward, creating a loosely organized line of showers and thunderstorms through the region starting Tuesday morning. Cloud cover and storm timing will limit instability ahead of the convection (mean values around 500 J/kg) and keep severe threats at bay.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
KEY MESSAGES:

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

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Subsidence and ridging is favored Tuesday night into Wednesday, promoting a return to dry weather and well above average temperature. Moisture may work underneath the ridge axis and allow for isolated thunderstorms Wednesday afternoon as convective temperature are met, but ensembles are bearish on this occurrence.

The late week period will be defined by the strength of the ridge axis building across the eastern CONUS and depth of troughs lifting out of the plains through the Great Lakes.
Strong ridge solutions would lead to well above average temperature and dry weather while weaker ridges would lead to above normal temperature with shortwave movement leading to periods of showers and thunderstorms. Any severe threat will depend on strength of that passing shortwave.

AVIATION /05Z SUNDAY THROUGH THURSDAY/
VFR is expected through the TAF period under a building ridge.
Mid and high level cloud cigs will continue into the afternoon, with CU rule and model soundings indicating a scattered CU layer developing across the region. The exception will be FKL and DUJ, where a low VFR broken CU cig is expected.

There is also a minimal chance of a mid to late afternoon shower or thunderstorm at FKL and DUJ, as a disturbance crosses southern Ontario/Lake Erie on the northern periphery of the ridge. Maintained the VCTS mention in the FKL/DUJ tafs for this potential.

LLWS is expected early this morning at FKL and DUJ, as a low level jet sets up across NW PA. The LLWS will end by 12-13Z as the jet dissipates.

Outlook
VFR is expected through Monday under a ridge of high pressure.
Restrictions are likely Tuesday in showers and a few thunderstorms with a crossing cold front. VFR returns Wednesday and Thursday under high pressure.

CLIMATE
Here is a table of the record high and low temperatures Sunday.
(* denotes current forecasted temperature exceeds value)

Record High Year Record Low Year Pittsburgh 88 (1990) 66 (2021)
Wheeling 89 (1942) 65 (2021)
Morgantown 91 (1986) 64 (1962)
New Philadelphia 90 (1990) 55* (2021)
Zanesville 89 (1914) 63 (1914)
Dubois 85 (1990) 65 (1990)

Here is a table of the record high and low temperatures Monday.
(* denotes current forecasted temperature exceeds value)

Record High Year Record Low Year Pittsburgh 88 (1899) 65 (1974)
Wheeling 86* (1942) 64 (1914)
Morgantown 91 (1899) 67 (1914)
New Philadelphia 90 (1986) 64 (1974)
Zanesville 90 (1899) 67 (1914)
Dubois 80 (1970) 61 (1974)

Here is a table of the record low temperatures Tuesday.
(* denotes current forecasted temperature exceeds value)

Record Low Year Pittsburgh 69 (1899)
Wheeling 58* (1911)
Morgantown 66 (1910)
New Philadelphia 63 (1991)
Zanesville 69 (1910)
Dubois 60* (1970)

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

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