Marine Weather and Tide Forecast for Rocky River, OH

NEAR TERM /THROUGH MONDAY NIGHT/
910 PM Update...
Another very quiet evening. Expecting an overnight windshift to a more southeasterly direction by morning and through Monday.
Lakeshore areas that were cool today with winds off the lake will not drop much in terms of temperatures tonight while inland areas not affected by the chilly lake will drop off considerably more from the daytime highs.

Previous Discussion...
High pressure currently located over southern Ontario will continue to dominate the region and bring pleasant and dry weather through Monday morning then start to build off to the east. Temperatures will be seasonable in the low 70s to end the day. Winds will start to shift out of the southeast later tonight and early Monday morning with an approaching warm front and low pressure that will unfortunately bring and end to the quiet weather. With the more southerly flow, overnight lows will stay rather mild compared to previous nights, in the low to mid 50s.

During the day Monday, the aforementioned warm front will be approaching from the south bringing increased cloud cover and precipitation chances. Precipitation will be scattered across the region starting in the late afternoon and into overnight hours Monday with better coverage expected after the near term.
A rumble of thunder is possible as well with the showers as there is a little instability but nothing more than general thunderstorms are expected. Temperatures on Monday will be fairly warm in the mid to upper 70s with the southern portions of the CWA staying a bit cooler due to seeing cloud cover early in the day.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
A weakening upper-level low will devolve into a trough as it lifts from the Tennessee Valley on Tuesday northeastward to overhead on Wednesday. Moisture content will be on the rise with surface dew points into the low 60s and temperatures in the 70s. Should see at least scattered showers and thunderstorms throughout the day, with PoPs peaking during the afternoon hours on Tuesday and Wednesday as building instability (to around 1000 J/kg) contribute to non-severe convective development. PoPs have increased to the 60-80% range both days, and while confidence in precipitation occurring is increasing, the scattered nature of rain should allow for periods of dry weather each day. Overnight hours should be mostly dry outside any lingering isolated showers.

LONG TERM /THURSDAY THROUGH SUNDAY/
An upper-level ridge briefly builds in, allowing for Thursday to mostly be dry, outside of any instability-driven isolated thunderstorm during the afternoon hours (mainly out east).
Meanwhile, a low pressure system approaches the west, located over the upper Midwest on Thursday. Broad southerly flow encompassing the eastern third of the CONUS will result in warm conditions on Thursday and Friday as the large warm sector envelopes our forecast area. Highs in the 80s are expected, and it will feel fairly humid for May around here.

Thunderstorm activity originating to our west is expected to move across the area Thursday night. Model guidance is starting to show some consistency with showing a favorable environment for at least a low threat for severe weather, despite the unfavorable timing.
Medium-range global ensembles are averaging around 1500-2000 J/kg of MUCAPE and 30-40 knots of deep layer shear during the overnight period, both of which are favorable for organized convection. It's possible additional convection could also lead to a more isolated severe weather threat Friday afternoon (as we remain in the warm sector), though it's far more uncertain due to the expectation for the Thursday night storms to bleed into Friday morning (and we are all too familiar with morning precipitation diminishing the afternoon severe weather threat).

ML/AI models have been showing this severe weather threat for a couple days, though on a much broader scale, and with the greatest severe weather threat elsewhere (Thursday to our west in IN/IL; Friday to our south and east). Trends in these models have indicated gradual uptick in severe weather probabilities, and more noticeably for the 12Z/Thu - 12Z/Fri period (i.e. with the Thursday night storms). This will be something to keep an eye on.

By Saturday, the upper-level low moves in the region, centered over the northern Great Lakes. There is some uncertainty with how fast this system moves but the most likely scenario is more it to exit by Sunday (with a few members showing it lingering into Sunday). The most likely scenario will result in scattered showers continuing into Saturday before a cold front crosses the region and high pressure builds in on Sunday. Should see downward trend in temperatures through the weekend with highs in the 70s on Saturday and in the 60s on Sunday.

AVIATION /00Z Monday THROUGH Friday/
VFR/mainly clear except for patchy cirrus tonight. An upper level low pressure system moving north northeastward will bring ceilings into the mix Monday after 12Z from the south, gradually lowering to MVFR and then IFR for some with scattered showers entering the fold late. Winds becoming southeasterly around 10kts Monday.

Outlook...VFR conditions will persist through Monday morning.
Non-VFR ceilings and periodic rain showers are expected Monday afternoon through Wednesday evening.

MARINE
East to northeast winds around 15 to 20 knots continue for a few more hours this evening, with 20 knot winds (and associated 3-4 ft waves) likely reserved to the central basin. A small craft advisory remains in effect through 8 PM for these conditions.

East to northeast winds continue overnight, though much weaker. A weak, occluded low approaches from the south before moving eastward to the mid-Atlantic region. This will tend to cause winds to become more southeast at night, and then more east during the day through at least Wednesday. Flow tends to become more southerly by Thursday and Friday. The probability of small craft advisory conditions are near zero through Thursday, with a low probability (around 20-40%)
at some point Thursday night through the weekend.

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