Marine Weather and Tide Forecast for West Homestead, PA

KEY MESSAGES
1) Scattered showers Friday and Saturday.

2) Gusty wind on Sunday.

3) Temperatures remain near normal with mostly dry weather through early next week.

DISCUSSION
KEY MESSAGE 1...
The cold front has cleared the forecast area east this evening leaving temperatures in the 40s and light drizzle in its wake.
Continued cold advection in NW flow is expected overnight as more organized light rain and drizzle transitions to more NW flow induced light showers closer to the lakes.

Aloft, a closed low will meander around the Great Lakes through Saturday as cold advection in the low levels continues.
Ensemble mean 850 mb temps dip to -1 to -3C as lapse rates steepen and lake- effect showers will ramp up. Initially, showers will be confined primarily along the Erie lakeshore overnight tonight until the low slides far enough east by the pre-dawn hours Saturday morning to flip the flow northwesterly, a weak impulse moves through, and the coverage of showers pushes a bit farther south into our area. REFS probability of precip mostly confines it north of Pittsburgh and in the PA and WV ridges with highest chances along I-80 and north. That said, an increase in neighborhood radius to account for spatial uncertainty in the hi res guidance does nudge it just a bit farther south as far as Pittsburgh metro. So, have ticked up PoPs a bit farther south. This will predominantly be cool, light rain showers with two exceptions:

1) The potential for some wet snowflakes to mix in in the pre-dawn hours as ground temperatures dip to or just below freezing in the ridges. The caveat there is that with displacement from the lake moisture fetch, column saturation cuts off well below -10C suggesting that snowflake production is likely going to be hard to come by, so it may be a cool drizzle produced within the supercooled liquid region of the cloud bearing layer.

2) Some graupel may mix in especially in the afternoon hours with fumes of SBCAPE and near dry adiabatic lapse rates up through the saturated layer.

KEY MESSAGE 2...
The pressure gradient will tighten up on Sunday on the periphery of developing low pressure off to our east. Low level flow in the 925- 850 mb layer strengthens on the back side of it as well nearing 50 knots over the ridges. Dependent on inversion height, exact direction, and potential mixing, Sunday could be gusty across the area and especially in the WV ridges. Probability of advisory criteria gusts (>46 mph) reaches up to 70% in Eastern Tucker County on Sunday. It may be a case that just the far eastern tip of the county gets especially gusty as the prevailing flow in the lower levels is westerly and thus favors downsloping to the east of our area. Will continue to monitor over the next 24-36 hours. In the lowlands, peak gusts being >30 mph are a decent bet with probability ranging from 40-80%.

KEY MESSAGE 3...
The early weekend trough departs on Sunday and surface high pressure establishes across the Ohio Valley returning mostly dry weather into next week with near normal temperatures. Latest 12 hour ensemble trends have turned a bit more in favor of the solution dominated by a subset of GEFS and Euro ensemble members in which the surface high is slower to build, and a slightly more amplified shortwave trough slides through early on Monday. This would return some scattered showers to the northern part of our area and NBM PoPs have nudged up in this direction. Regardless, ensembles converge to better agreement that the high does become our dominant influence with dry weather on Tuesday. The pattern then becomes very deviant into the second half of the week as another trough tries to dig out of the Great Lakes and quickly amplify over the eastern half of the country. How deep it is and when it arrives remain unknown, but one would expect that a more unsettled pattern returns with surface low development somewhere downstream. That may be local or well off into the Atlantic at this point. Once we get a better idea of how deep and how progressive the trough will be, we'll be able to start to pin down the potential location and track of a surface low.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
A mix of VFR, MVFR, and IFR conditions are currently happening across terminals with a passing cold front this evening. Areas just ahead or in close proximity of the front are experience light rain/drizzle and MVFR and IFR cigs/vis. Terminals in the wake of the front are experience a period of VFR (BVI/HLG/ZZV).

All terminals will return to VFR conditions in the next 3 hours as the front exits east and drier air returns. However, with a pivoting low pressure system just north of Pittsburgh expected to descend south early Saturday morning, between 06Z and 10Z, MVFR to IFR cigs are expected to return along with spotty rain showers.

Cig improvements are expected late Saturday, between 20Z and 23Z, as high pressure builds to our south. FKL and DUJ will likely hold on to at least MVFR cigs through early Sunday morning.

Outlook...
VFR conditions are expected across the region Sunday afternoon with advancing warm air from the west. A passing cold front late Sunday into Monday could return cig restrictions north of PIT.

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