Marine Weather and Tide Forecast for Mentor, OH

NEAR TERM /THROUGH THURSDAY/
9:10 AM Update...
Made some minor adjustments to hourly PoPs, temperatures, and dew points to reflect current observations and trends. Beginning to see some convection attempting to initiate along the Indiana-Ohio border this morning which will gradually push east this morning and afternoon.

640 AM Update...
Negative vorticity advection creating a lull in the showers for the western CWA spreading eastward. Updates included minor adjustments to the timing of the convection after 17Z today developing in the western CWA and spreading eastward.

Previous Discussion...
Intensifying band of frontogenesis working northeastward through the CWA this morning with a line of non severe storms. Lull in its wake in area of NVA within the southwest flow aloft brings a brief period of drying. Upper level closed low rotates into the lower Great Lakes after 12Z today while the associated surface low tracks through northern Ohio. This track of the surface low is now adjusted northward compared to 24 hours ago when the path was more through the southern portion of the state. Back to the upper levels, a trough axis from the closed low will rotate northeastward into the CWA after 16Z with strong PVA in the flow. This will become the focus for convective development this afternoon. While this is occurring, just downstream of the line of convection, should see a brief spike in favorable thermodynamic parameters to support a brief window of marginally severe storms. Think this threat is low overall, but should develop surface based CAPE with modest diurnal heating coupled with some favorable low level lapse rates. Dynamics of the column are lacking in flow overall with the strongest low/mid level flows further south of the CWA Should be enough for a little bit of organization of this line however, and the proximity to the occluded front could complicate matters with abrupt increases in the low level directional shear. As a result, some rotation should be expected, even in some of the more innocuous storms that form. SPC going with a marginal risk largely for the eastern half of the CWA
As the convection commences, column will likely water load, which, again, should help limit the severe threat to the onset. As the convection crosses the occluded front and into the northeast zones, the forcing PVA will weaken.

Upper level low will push eastward into NY/PA by Thursday morning now transitioning the even to a low level cold air advection scenario with moist aligned northwesterly flow off of Lake Erie.
850mb temperatures will drop towards 0C, and POPs increase once again over the eastern half of the CWA

For the temperatures today, with the new northward extent of the west to east track of the surface low, there should be for a limited period of southerly flow/warm sector residence time. Temperatures today have come up a couple degrees from previous forecast runs and could reach the 70F in isolated portions of the southern zones. In the wake of the low for Thursday however, with cold air advection occurring, a rather chilly lower to upper 50s forecast remains likely, and will be the coolest day of the 7 day forecast period.

SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/
The short term period will continue to be dominated by the slowly drifting upper level trough and associated surface low over New England. Wrap around moisture on the back side of the low will allow for continued showers across northeast Ohio and northwest Pennsylvania as colder 850 mb temperatures push southeast across Lake Erie and result in weak lake induced instability. The chance of lake enhanced rain showers will continue through Saturday before drier air associated with a weak upper level ridge pushes over the area and allows for a break in precipitation Saturday night.
Unfortunately, the high pressure that will push over the area will have a Canadian origin, prolonging the below average temperatures across the area. Highs on Friday will climb into the 50s before warming slightly on Saturday into the upper 50s to mid 60s.
Overnight lows will linger in the 40s.

LONG TERM /SUNDAY THROUGH TUESDAY/
During the long term period, another surface low is expected to develop over the Mid-Mississippi River Valley and track east towards the southeast. There is a bit of uncertainty in how far north the center of this low will track which will impact the chance of precipitation through the period. Both the GFS and Canadian bring the low closer to the Ohio River Valley on Monday/Tuesday which would present a more likely chance of precipitation, however the ECMWF keeps the low further south and allows for a drier solution in the long term. Given the uncertainty, opted to cap PoPs at slight chance for late Sunday through Tuesday, but will need to continue to monitor the overall trend in the system. Either way, given the fact that the area looks to remain on the northern side of the low, limited potential for severe weather is expected at this point with additional below average temperatures to continue through the long term period. Highs will linger in the 60s with overnight lows dropping into the upper 40s to low 50s.

AVIATION /12Z Wednesday THROUGH Sunday/
Periodic IFR expected across the forecast as low pressure will move through the region Wednesday. A brief reprieve to the rain showers this morning for the central and western terminals, but MVFR/IFR ceilings will remain dominant. Afternoon thunderstorm activity expected to develop in northwest/north central Ohio and then spread ENE towards New York/Pennsylvania. TAFs are timed with 2hr TEMPO grids for the line of storms, including wind gusts and visibility restrictions down to IFR. Showers after this line will be more off and on in nature for the back half of the TAF, but again, expecting ceilings down into the IFR range if not already there heading into the tonight period.

Outlook...Non-VFR expected with periodic rain showers and isolated thunderstorms Thursday through Saturday.

MARINE
Hazardous marine conditions are expected to continue today as low pressure moves east across Lake Erie. Initially this morning, winds from the east-northeast of 15-25 knot will persist ahead of the low.
This will result in waves building to 4-6 feet across primarily the central and western basins. As the center of the low moves over Lake Erie by this afternoon, the gradient will significantly weaken and variable winds of 5-10 knots will briefly persist into Thursday. As the center of the low drifts towards New England on Thursday, northwest winds of the backside of the low will increase to 15-25 knots with waves building to 4-6 feet across the central and eastern basins. These conditions will persist into Friday before a weaker surface trough allows for the northwest winds to weaken to 10-15 knots by Friday evening. Additional marine headlines will likely be needed on Thursday into Friday as a result of the stronger and onshore flow. Winds will continue to weaken to 5-10 knots this weekend as brief high pressure builds over the region.

CLE WATCHES/WARNINGS/ADVISORIES
OH...Beach Hazards Statement until 8 PM EDT this evening for OHZ007- 009-010.
PA...None.
MARINE...Small Craft Advisory until 10 PM EDT this evening for LEZ142>146.
Small Craft Advisory until 10 AM EDT this morning for LEZ147>149.