Marine Weather and Tide Forecast for Flat Rock, OH

NEAR TERM /THROUGH TODAY/
1000 PM EST Update...
Despite an inversion over the local area, there has been just enough mixing for scattered and periodic wind gusts of 25 to 35 mph with isolated and infrequent gusts to 40 to 45 mph this evening. Gusts should peak with the peak of the LLJ through about Midnight before beginning to diminish early Sunday morning. Adjusted the wind gust forecast to account for latest observations and newer guidance, which has resulted in increased gusts for the entire area. The highest winds are likely near and west of the I-71 corridor and close to the lakeshore. Winds will likely be locally higher due to downsloping effects in northern Erie County, PA, so issued a (somewhat marginal) Wind Advisory until 7AM/12Z Sunday morning. Will continue to monitor observations areawide tonight and will consider Special Weather Statements for wind gusts if winds consistently gust above 40 mph in any given area. Will also keep an eye out for any signs of further boundary layer decoupling, which would result in a significant decline in wind gusts.

Other than the changes to wind gusts, very few changes were needed with the forecast outside of making small increases to temperatures due to warm air advection and slightly lowering dew points due to mixing.

Previous Discussion...
Quieter weather prevailing into this evening with the lake effect shut down at this point. Remaining tranquil through the overnight period with the exception of a weak surface/low level thermal trough clipping the far northeast zones in NW PA/NE OH.
Throw some slights back in the mix and some low level cloud cover representing this feature, but POPless again after 15Z Sunday for the bulk of that day. Meanwhile, split flow regime aloft in place with two upper level lows moving eastward into the plains. The southern stream trough axis pushes into the Ohio Valley with a warm front into the region introducing the beginnings of a milder regime across the CWA Antecedent upper level ridging already has temperature improvements for Sunday which will become enhanced by the warm frontal passage Sunday night and heading into the short term forecast period. Saturated isentropic lift with the warm front brings stratiform rain in from the southwest Sunday night with rain overspreading the entire CWA and pushing eastward by 12Z Monday. Looking at a quarter to half inch in the southwestern zones of the CWA by the break point with the short term forecast period 12Z Monday.

SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/
An active and mild short term period is in store across the region as temperatures rebound to above average in the upper 40s to lower 50s. Widespread rain is expected on Monday, particularly in the morning, resulting from broad isentropic lift associated with a weak mid-level wave moving northeast across the Ohio Valley. Although rainfall amounts appear to be generally on the lighter side, there is a subtle signal of totals nearing 0.50 inches across Northeast Ohio and Northwest Pennsylvania with modest dew points in the 40s expected. Recent NOHRSC analysis reveals snow water equivalent in excess of 4 inches across portions of the snowbelt, resulting from the recent historic lake effect snows. Confidence is low for any significant flooding, but certainly can't rule out areas of minor flooding where significant snowpack currently exists.

A more potent upper-level trough will move east across the central and eastern CONUS Monday night through Tuesday, with more rain possible Tuesday afternoon into Tuesday night, particularly along and east of the I-71 corridor. A strong cold front will accompany this system Tuesday night, ushering in another blast of arctic air into the region.

LONG TERM /WEDNESDAY THROUGH SATURDAY/
Confidence is increasing for accumulating lake effect snow once again across the primary snowbelt Wednesday night through Thursday as another blast of arctic air descends across the Great Lakes.
Confidence is high for 850 mb temperatures to reach at least -15 degrees C on Thursday, with some ensemble members even suggesting low probabilities of 850 mb temperatures reaching as low as -20 degrees C. Boundary layer winds will largely mimic the Thanksgiving lake effect event, with W to SW winds expected and minimal directional shear present. A lake aggregate trough should largely limit accumulations outside of the primary snowbelt, with initial indicators suggesting the lakeshore areas will see the highest snowfall once again. Thursday will be the coldest day of the long term period with highs in the low to mid-20s in addition to single digit to near-zero wind chills likely. Recent LREF guidance does show low (30%) probabilities of sub-zero wind chills Thursday morning so will be something to monitor.

A ridge will begin to build in from the central CONUS by late Friday into Saturday, signaling an end to any lingering lake effect snow across the region. Temperatures will rebound back to the upper 30s to lower 40s on Saturday.

AVIATION /06Z Sunday THROUGH Thursday/
VFR conditions expected at the majority of TAF sites through tonight. Low pressure system will cross north of Lake Erie this afternoon which will drop ceilings to MVFR at KERI. Conditions will deteriorate from southwest to northeast near the end of the TAF period (after 03Z/Mon) as low pressure enters the region. Have introduced PROB30 for reduced cigs/vis in -SHRA for all sites except for KYNG and KERI.

Elevated southerly to southwesterly wind gusts between 25-30+ knots will diminish below 12 knots by this afternoon. Low level wind shear will remain through 12Z this morning.

Outlook...Non-VFR expected tonight through Tuesday in rain.
More non- VFR expected in post cold frontal snow/lake effect snow in Northeast Ohio and Northwest Pennsylvania Wednesday and Thursday.

MARINE
Marine conditions will continue to deteriorate this evening and overnight, with southwest Gales to 35 knots developing across the central and eastern basins of Lake Erie. Winds will occasionally gust in the 40 to 45 knot range into Sunday morning, with isolated higher gusts of 50 knots possible in the open waters. Winds will briefly shift towards the west Sunday morning, decreasing to around 20 knots by Sunday afternoon, then to 10 knots or less out of the south by Sunday evening.
Relatively quieter marine conditions will then persist on Monday into Tuesday with southwest flow around 10 to 15 knots. A cold front will cross the lake late Tuesday, with a secondary and more potent cold front expected to arrive on Wednesday.

A Low Water Advisory also remains in effect as persistent southwest winds will result in water levels across the western basin of Lake Erie falling below the critical mark for safe navigation of 2 inches below low water datum. There is a modest potential (around 50%) for water levels to reach as low as 12 inches below low water datum late tonight into Sunday morning.

CLE WATCHES/WARNINGS/ADVISORIES
OH...None.
PA...Wind Advisory until 7 AM EST this morning for PAZ001-002.
MARINE...Small Craft Advisory until 10 AM EST this morning for LEZ142>144.
Low Water Advisory until 10 AM EST this morning for LEZ142>144- 162>164.
Small Craft Advisory until 4 PM EST this afternoon for LEZ145- 146.
Gale Warning until 7 AM EST this morning for LEZ147>149- 166>169.