Marine Weather and Tide Forecast for Avonia, PA

KEY MESSAGES
1) Fog and low stratus developing this morning could allow for poor visibility conditions for the morning commute, especially in Northeast Ohio and Northwest Pennsylvania.

2) One more round of severe weather is expected on Saturday afternoon with higher confidence in Northeast Ohio and Northwest Pennsylvania. Damaging wind gusts, large hail, and a tornado or two are all possible with storms.

3) A cold air mass across the region will allow for residual rain and some isolated snow chances on Sunday. The cold air will allow for frost/freeze potential on Sunday and Monday nights.

DISCUSSION
KEY MESSAGE 1...
A brief air mass change is occurring across the region this morning behind a cold front with 50s temperatures overtaking a relatively moist low level atmosphere and moving over Lake Erie, which is also around 50 degrees at the surface. With this cooler air mass, fog is developing across the lake and low stratus is beginning to push into far Northeast Ohio and Northwest Pennsylvania. Conditions should continue to deteriorate through the morning hours. Have issued a brief Dense Fog Advisory for NE OH and NW PA, as visibility falls this morning. Fog should mix out by this afternoon with southerly return flow coming back into the area.

KEY MESSAGE 2...
With several days of messaging in SPC outlooks, most of the attention of the forecast is on the severe weather potential on Saturday with a strong, pattern changing cold front. From a synoptic standpoint, the setup remains very similar to previous forecast cycles with a deep upper trough entering the central US and support a low pressure system through the Great Lakes region and an associated cold front. The low will pass to the northwest on Saturday, while the surface front will cross the area by Saturday evening. The environment ahead of the front remains conditional for severe weather, as there will be upstream activity today that will eventually reach the forecast area as decaying convection/outflow by Saturday morning. This could limit the atmosphere recovery for the entire severe weather setup. However, strong low level flow with 30 kts at 925 mb could allow for some quick recovery in the warm sector with temperatures into the 70s and dew points trying to return into the 60s. The more recovery into the region will dictate how expansive the severe weather threat could be on Saturday.

Overall, the main change with the forecast this morning is that the timing of the front has slowed just slightly by an hour or two, which may allow more time for a recovered atmosphere and organization of showers and storms ahead of the front to be over Northwest and North Central Ohio before pushing east.
Therefore, the Day 2 Slight Risk for severe weather from the Storm Prediction Center is a couple counties west, now reaching the Interstate 71 corridor. All severe hazards are on the table with damaging wind gusts, large hail, and/or a tornado or two.

KEY MESSAGE 3...
After the strong cold front on Saturday, a cooler than normal air mass will settle into the region for Saturday night through Tuesday morning with highs in the upper 40s to mid 50s and lows in the upper 20s to mid 30s. A residual trough across the region on Sunday will support some scattered rain showers and in the upslope regions of NW PA and far NE OH, there could be some brief changeover to snow on Sunday and Sunday night, but snow accumulations aren't expected. The main concern for the period will be the low temperatures near/below freezing and if the atmosphere will remain favorable for frost conditions across the forecast area. The frost/freeze program is in effect for all of Ohio and the probability of headlines for Sunday and Monday nights continue to increase with every model cycle. Warming conditions are expected on Tuesday, ending the frost/freeze threat for the forecast period.

AVIATION /12Z Friday THROUGH Tuesday/
Conditions vary across the region this morning from LIFR to MVFR with low stratus and areas of fog. The low stratus and fog will erode away later this morning with VFR conditions by midday. VFR will continue through the afternoon into overnight with increasing high and mid level clouds. Winds will be light today around 5 knots starting out northerly becoming southeasterly this afternoon. Southerly winds will increase late tonight 10 to 15 knots with gusts up to 25 knots by early Saturday morning.

Outlook...Periodic rain showers and thunderstorms with non-VFR are expected during the predawn hours of Saturday morning through Saturday evening. Additional periods of rain with non- VFR should occur overnight Saturday night through Sunday evening. Rain may mix with or change to scattered wet snow at times Sunday morning and again Sunday evening.

MARINE
Dense fog has developed over the lake this morning and Otherwise, quiet marine conditions are expected today. Weak high pressure will move across the area. Winds will be light and variable today with light waves expected on the lake. Winds will become southeasterly to southerly 5 to 10 knots tonight. A cold front will approach the lake from the west on Saturday. Southerly winds will increase 10 to 20 knots ahead of the front. Behind the front, westerly winds 10 to 20 knots are expected Saturday evening and night. Conditions may get to a SCA headline needed.
Westerly winds 10 to 20 knots will continue on Sunday. Another cold front will move across Lake Erie Sunday night with northerly winds 10 to 15 knots expected into Monday. High pressure and lighter winds will build in over the lake late Monday into Monday night.

CLE WATCHES/WARNINGS/ADVISORIES
OH...Dense Fog Advisory until 11 AM EDT this morning for OHZ011>014- 089.
PA...Dense Fog Advisory until 11 AM EDT this morning for PAZ001>003.
MARINE...Dense Fog Advisory until 11 AM EDT this morning for LEZ142>149- 162>169.