textproduct: Cleveland

WHAT HAS CHANGED

Morning and early afternoon rain and storms have exited the area. We are now monitoring for storms to track into at least portions of the area this evening as a cold front moves in from the northwest.

KEY MESSAGES

1) Scattered thunderstorms are expected this evening, especially across Northeast OH and Northwest PA. A few storms may be severe, with damaging winds the greatest risk.

2) Anomalously-cool air mass arrives on Wednesday with lake- effect showers possible.

3) Temperatures return near or slightly above normal by the end of the week and weekend. Shower and thunderstorm chances increase by early next week.

DISCUSSION

KEY MESSAGE 1... The first two rounds of convection have departed the area. A cold front extends from southeast Lower MI into northern Indiana and will sweep southeast across the area this evening. Organized convection is ongoing from the Thumb of Michigan into southern Ontario, with a few more isolated cells farther southwest along the front. The thunderstorms occurring from MI into ON are being aided by a vort max that's very evident on water vapor imagery.

The thinking is that isolated to scattered convection will play out this evening across our area. The greatest confidence, coverage, and potential severity is expected from far Northeast OH into Northwest PA, as the more organized activity aided by the vort max from MI into ON builds east-southeast. Very dry mid-levels, a warm layer around 600mb, and weaker forcing make coverage and severity of any convection farther west-southwest across our area more questionable. MLCAPE of 1000-2000 J/KG, DCAPE values increasing to 700-1000 J/KG (higher west), and effective bulk shear values remaining in the 40-50kt range can support organized convection with a severe threat through this evening, especially across far Northeast OH and Northwest PA. Potential limitations include the generally poor mid-levels mentioned above (especially farther west), more modest low-level lapse rates farther east across our area due to limited heating, and effective storm relative helicity (SRH) values gradually weakening to 100-150 m2/s2.

Overall, there's greater confidence in convection with potential for a couple or few severe storms across far Northeast OH and Northwest PA after 4 PM. Damaging winds would be the main hazard, though a bit of hail and perhaps a low-end tornado threat can't be fully ruled out here. Farther west, closer to and west of the I-77 corridor, more isolated storms are favored as the front moves through this evening with lower confidence in any severe weather threat. The environment can support a damaging wind risk if we see any storms that are deep/organized enough to become severe farther west, though overall confidence is lower. Any severe risk should diminish by 9 PM, though a few showers/storms may linger through about midnight as the front continues across the area and as we potentially see a lake enhanced shower or storm come off the lake behind the front.

KEY MESSAGE 2... Quite the airmass change behind the front as we head into Wednesday. 850mb temperatures will dip to around 8C on Wednesday, supporting surface highs struggling to get much above 70. Overnight lows will dip into the 50s and lower 60s tonight, and then well into the 50s Wednesday and Thursday nights. Typical colder spots from interior eastern OH into interior PA should see some 40s one or both of those nights.

It will be chilly enough aloft for some lake effect clouds and rain showers to come off the lake in the north-northwest flow overnight tonight through Wednesday. This is not a particularly noteworthy lake effect setup, just enough for meteorologists and enthusiasts to look at the satellite and radar late tonight or Wednesday and remark "oh, there's some lake effect on July 22nd". Lake effect should largely wind down by Wednesday night, though guidance suggests that a land breeze may focus some lake effect near the south shore of Lake Erie through early Thursday, so the forecast maintains some low POPs through early Thursday.

KEY MESSAGE 3... Troughing will gradually lift out of the Northeast through this weekend, allowing our temperatures to gradually warm from the end of this week into early next week. Temperatures may climb back to above normal by Sunday. There is some disagreement over when the next system comes in, it's possible Monday is quite warm before the next cold front moves through. Mainly dry weather is expected through the weekend, with more organized shower and thunderstorm potential returning Monday into Tuesday as the next shortwave and cold front drop in.

AVIATION /18Z Tuesday THROUGH Sunday/

Showers and thunderstorms are exiting out to the east currently with MVFR ceilings behind to a line from KCLE down through KMFD. Any remaining thunderstorms could drop visibility and ceilings down to IFR conditions temporarily before rebounding to MVFR. VFR conditions are seen to the west at KTOL and KFDY with a range of scattered to broken deck from 2-5kft. A cold front will sweep in from the west late this evening, with possible showers and thunderstorms, generally east of KCLE and KMFD which could bring conditions down to non-VFR. The majority of precipitation will exit to the east after midnight with possible lake effect showers at KCLE and KYNG overnight into tomorrow morning. There's potential after the cold front moves through for ceilings to drop down to MVFR as far west and south as KMFD and east through KERI and KYNG with the lake effect.

Winds will be out of the south to southwest at 10-15 knots with gusts up to 20 knots. Within any thunderstorms, gusts as high as 35 knots will be possible. Winds will shift with the cold front late this evening to be out of the north-northwest at around 10 knots with gusts up to 20 knots possible through the end of the TAF period.

Outlook...Residual non-VFR possible through late Wednesday evening in lake effect rain showers and clouds across the eastern half of the area.

MARINE

Southwest winds will increase to 15 to 25 knots this morning, resulting in waves of 3 to 5 feet in the nearshore zones from roughly Vermilion to Ripley NY. Winds may briefly diminish as a cold front crosses the area this afternoon/evening, but strong cold air advection will cause winds to shift to the northwest and increase to about 20 knots overnight, which will produce continued elevated waves into Wednesday. The Small Craft Advisory from Maumee Bay to the Islands has been adjusted to start early this morning and end at 4 AM Wednesday morning to account for the enhanced northwest flow behind the cold front. Meanwhile, the Small Craft Advisory remains in effect from the Islands to Ripley NY from 8 AM this morning until 10 PM Wednesday evening. Thunderstorms are likely this morning and afternoon which will result in higher winds/waves.

Winds will diminish below 10 knots by early Thursday morning and expect light (10 knots or less) and variable flow through at least the first half of the weekend.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement through Wednesday evening for OHZ010>012-089. PA...Beach Hazards Statement through Wednesday evening for PAZ001. MARINE...Small Craft Advisory until 4 AM EDT Wednesday for LEZ142-143. Small Craft Advisory until 10 PM EDT Wednesday for LEZ144>149.