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 /00Z Wednesday THROUGH Sunday/

Showers and thunderstorms are exiting to the east along with a cold front, as VFR conditions return to northeast OH. MVFR conditions will linger across NW PA with only brief periods of improvement expected. Lake effect showers and isolated thunderstorms will impact KCLE, KCAK, and KYNG briefly overnight, ending before sunrise. Ceilings are expected to drop to MVFR from KMFD eastward through KERI and KYNG overnight, continuing beyond sunrise tomorrow morning.

Winds are expected from the north-northwest at around 10-12 knots with gusts up to 20 knots thing evening, generally falling below 10 knots with gusts ending by morning.

Outlook...Occasional non-VFR conditions are expected through late Wednesday evening in lake effect rain showers and clouds across the eastern half of the area.

MARINE

Winds across Lake Erie are currently around 15-25 knots out of the west-southwest with waves 2-5 feet with the upper end of those occurring over the open waters. A strong cold front will pass west to east across the lake late this evening and winds will shift to be out of the northwest at 15-25 knots. Waves will build as a result within the near shore zones east of the islands to 3-5 feet with occasionally waves around 6 feet. A Small Craft Advisory is currently active for all near shore zones to account for the current conditions and for the conditions behind the front. The zones to the west of the islands will see improvements shortly after frontal passage and the small craft will last until 4AM tomorrow morning. For areas to the east, conditions won't improve until late Wednesday night. There will be increase rip risk as well from Lorain Co east through Erie, PA with the increased winds and waves through late Wednesday night as well. For Wednesday, there is a marginal risk for waterspouts within showers as the lake is fairly warm and a colder air mass moves in from the north. Conditions will improve early Thursday morning through Saturday night as high pressure builds into the region. Winds will decrease to less than 10 knots by Thursday morning with waves subsiding to less than 2 feet.

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.