Marine Weather and Tide Forecast for Whitaker, PA

KEY MESSAGES
1) Isaias will continue its departure through tonight.

2) Rain chances return mid-week; impactful weather is possible Friday/Saturday with a strong low pressure system.

DISCUSSION
KEY MESSAGE 1...
Isaias will continue to move east into tonight. Precipitation and gusty winds will subside as generalized ascent and gradient winds move with it. Precipitation chances will last the longest southeast of Pittsburgh into the high terrain with orographic lift and greatest proximity to coastal low development, but median 24 rain through 2pm Monday sits only around an additional 0.1 to 0.3 inches with a worst-scae scenario bulls-eye of 1.5" should showers from tonight. Even this would likely not lead to any additional flood concerns. As for wind, gusts up to 30-40mph in high terrain this afternoon will calm to light northwest winds tonight, so no additional concerns there as well.

KEY MESSAGE 2...
Into mid-week, the 500mb pattern will tend more towards a western trough and an eastern ridge, which will actually push temperatures close to 15 degrees above normal Tuesday. A low passing to the north will accelerate gradient low-level flow Tuesday, though LREF keeps a 90% chance of SBCAPE >500, and a 50% chance of values near 0. SPC has hoisted a Day-3 Marginal Risk in north central PA for now, chances locally are highest (but still low) north of I-80 with wind as the primary threat.

Better rain chances arrive into Wednesday as a weak shortwave moves through, with QPF totals anywhere from a light accumulation to 0.50" (NBM 25th-90th), should the shortwave materialize.

The big question then becomes what will happen with a late-week system, of which, ensembles are still highly uncertain. The main driver of uncertainty is the timing and placement of a digging eastern tough. In scenario 1, the trough digs east of the area sometime Thursday and Friday. Is this scenario, the area would be warmer than ensemble means and less unsettled. In scenario 2, the tough barrels down directly onto of the area (favored Friday into Saturday, which could bring some rain, winds (approaching advisory criteria), a strong cold front, and even the lake-enahnced snow/rain shower potential into Saturday. In scenario 3, the trough may drop to into the Midwest sometime Friday/Saturday with rain ahead of it, and bring a longer period of cool and windy conditions as the upper low struggles to rejoin the flow into next weekend.



AVIATION /16Z SUNDAY THROUGH THURSDAY/
MVFR to IFR cigs and vis will continue to overspread the region from south to north as the remnants of the tropical disturbance venture across the region. Moderate rain will likely be heaviest through 17Z today before dry slot ventures into the region from the west. Enhanced downsloping may create periods of VFR cigs for LBE and MGW due to subsidence.

With a strong vertical wind profile, gusty conditions and wind shear are expected from now through 14Z this morning. Gusts will likely range between 20kts-30kts with higher values near LBE/MGW (up to 25kts-35kts). Wind will begin to ease between 18Z and 23Z today.

Residual moisture within the boundary layer along with the easing wind will likely keep cigs low (MVFR to IFR) into early Monday morning despite decreasing rain chances.

Outlook...
VFR conditions are expected by Monday afternoon with warm, southwest flow dissipating any lingering low-level cigs.

A cold front may return restrictions late Tuesday.

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