Marine Weather and Tide Forecast for Grand River, OH

NEAR TERM /THROUGH TODAY/
9:30 PM Update...

The first wave of showers will continue to gradually pivot NE of the region over the next few hours as a dry slot works in.
Watching the line of convection over Indiana at the moment.
MUCAPE decreases rapidly with eastward extent, so expect this to weaken upon reaching NW Ohio. However, the remnants of the convection will bring another wave of showers overnight in the 03-08Z timeframe from west to east, and perhaps a few rumbles of thunder to a Findlay to Marion line. No changes needed to PoPs or temperatures overnight.

6:30 PM Update...

Increased PoPs to a larger area of likely and categorical this evening as the initial band of light showers associated with mid-level isentropic ascent lifts across the region. QPF will be very light, but wanted the main message to be that it will at least lightly rain in most areas. The rest of the forecast remains on track.

Original Discussion...

Low pressure will continue to push east into the lower Great Lakes region tonight before stalling in the vicinity of Lake Erie Wednesday night. Periods of showers and thunderstorms will be likely through the near term forecast period with strong to severe storms and isolated flooding possible on Wednesday.

Scattered showers will continue to push east across the local forecast area tonight into early Wednesday morning. Can't rule out an embedded and isolated thunderstorm late tonight south of US-30 before we see a brief dry window early Wednesday morning. The surface low will move over northern Ohio late morning/early afternoon on Wednesday which will allow for showers and thunderstorms to redevelop. With the brief dry window there is the potential for some surface heating to take place early Wednesday which would support a few hundred Joules of MLCAPE Wednesday afternoon. Strong thunderstorms with the potential of isolated severe thunderstorms, mainly across southeastern portions of the forecast area, are possible tomorrow. Primary threat in any strong to severe storm that does develop tomorrow afternoon will be damaging winds and large hail given cold temperatures aloft. The SPC SWODY2 has placed a very small sliver of the forecast area from Akron to Youngstown and points south. There is also a small chance for a brief tornado depending on the position of the warm front tomorrow.

In terms of rainfall, the storm total QPF amounts have remained fairly unchanged with most of the forecast area receiving at least 0.50- 0.75 inches of rain tonight through Wednesday night.
Higher storm total QPF amounts exist east of I-71 with total amounts ranging between 1.00 and 1.50 inches. There remains a heavy rainfall risk tomorrow afternoon given a skinny CAPE profile, PWATs nearing the 90th percentile, and cloud layer wind speeds around 20 knots. Additionally, HRRR probabilities of 1" or more in 6 hours show pockets of 30-40% mainly south of US-30 and east of I-71 tomorrow afternoon. Isolated flooding is possible in any training thunderstorm with WPC placing the above mentioned area in a Slight Risk (Level 2/4) in their Day 2 Excessive Rainfall Outlook.

Overnight lows tonight will settle in the low to mid 50s before rising into the low 60s Wednesday afternoon. Slightly cooler on Wednesday night with lows hovering around 50 degrees.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/
The main story for the long term period will be the persistent upper- level troughing regime across the Eastern CONUS with below-average temperatures in the mid to upper 50s expected. The root cause of this dreary and seasonable-cool weather will be large upper-level trough across the Eastern CONUS. This upper-level trough will be accompanied by persistent surface troughing around a closed surface low and ~0C 850 mb temperatures, resulting in periodic rain showers, perhaps somewhat aided by a ~15C Lake Erie, across the area Thursday through at least Friday night. For the most part, rainfall amounts should be on the lighter side, generally a quarter of an inch or less.

LONG TERM /SATURDAY THROUGH TUESDAY/
Below-average temperatures are favored for the long term period as a primarily troughing pattern persists across the Eastern CONUS. Weak upper ridging may begin building in from the west on Saturday, though lingering surface troughing across the Eastern Great Lakes will likely result in continued, light lake effect rain showers and/or cloudiness across Northeast Ohio and Northwest Pennsylvania.
A mid-level shortwave will move east through the Lower Ohio Valley along the base of the upper-level trough on Sunday, though it appears this system may just skirt to the south of the area. By late Monday into Tuesday, models appear to favor another large upper- level trough diving southeast across the Great Lakes, which would result in additional chances for clouds/rain showers and/or below average temperatures.

AVIATION /06Z Wednesday THROUGH Sunday/
In a period of unsettled conditions across the entire region with waves of showers with some thunderstorms expected for the duration for the forecast. A line of TSRA is moving southwest to northeast during the overnight period that will be followed by a lull in the activity before another upper level wave moves in for Wednesday. This will trigger another round of convection, expected after 16Z with some thunderstorm potential embedded within, but for the terminals, will roll with showers for now.
Several hours of IFR ceilings should be expected, with MVFR otherwise for the most part, and visibilities coming down in precipitation. Winds will be variable as a result of an area of low pressure and its counterclockwise flow passing to the south of the area, but will largely end up westerly 10-15kts at the end of the TAF period.

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

MARINE
Rough marine conditions are expected across much of Lake Erie into Wednesday with east to northeast flow of 15 to 25 knots. Gradual improvement of the lake conditions is possible Wednesday evening as a surface low lifts north through the area, shifting flow back towards the southwest. Rough marine conditions may return on Thursday as flow shifts back towards the west to northwest behind the low and associated occluded front, 15 to 20 knots. Persistent west to northwest flow of near 20 knots may continue through Friday night with additional Small Craft Advisories possible. Winds are expected to weaken by Saturday into Sunday as surface high pressure briefly builds across the area.

CLE WATCHES/WARNINGS/ADVISORIES
OH...None.
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.