textproduct: Cleveland

WHAT HAS CHANGED

Slowed down the timing of thunderstorms for this afternoon with the main window for stronger storms between 5 PM in the west and 10 PM in the east. Lowered high temperatures across the north by a couple degrees behind the front on Wednesday. Chances of a widespread rain continue to increase for Friday and Friday night.

KEY MESSAGES

1) Hot and humid conditions continue today with showers and thunderstorms expected late this afternoon into tonight. There is a Slight Risk of severe weather (Level 2 of 5) with thunderstorms today with scattered pockets of damaging winds the main hazard.

2) Much cooler air will arrive behind a cold front for Wednesday and Thursday. High temperatures on Wednesday will be 20-30 degrees cooler than Tuesday.

3) Widespread rain is expected Friday afternoon and night with unsettled conditions continuing into the holiday weekend.

DISCUSSION

KEY MESSAGE 1... Low pressure is located over the Upper Peninsula of Michigan early this morning and is forecast to continue northeast today. Showers and thunderstorms are ongoing across Wisconsin and western Illinois but are expected weaken through early morning as they continue to move eastward. Meanwhile the local area is located in the warm sector with high temperatures forecast to reach the upper 80s again this afternoon and dewpoints gradually creeping upward into the mid 60s by this afternoon. This will result in slightly more humid conditions than Monday but with fairly similar heat index values near 90 degrees.

Instability ahead of the eastward moving trough is expected to weaken through early this morning then start to build across eastern Indiana and Ohio for the afternoon. ML CAPE values of 1500-2000 J/kg are expected in NW Ohio with closer to 1200 J/kg in the east. A shortwave moves through the Upper Great Lakes late this afternoon and a pre-frontal surface trough advances into NW Ohio and is expected to serve as a focus for showers and thunderstorms. While a stray shower is possible earlier in the day, the main area of activity is expected to develop towards 5 PM near Toledo and spread eastward through the evening. High level cloud may outpace the better forcing but as we get towards evening that may not be as significant. Overall expecting a corridor of 20-30 knots of 0-6km shear which could support scattered strong to severe thunderstorms. Damaging winds are expected to be the primary hazard but can not rule out a few reports of hail or an isolated tornado, mainly if surface winds back sufficiently ahead of the trough. Locally heavy rain is also expected with thunderstorms tonight with pockets of 0.50" to 1.25" as storm motion may be parallel to the flow aloft.

KEY MESSAGE 2... The above mentioned cold front will extend from roughly Youngstown to Marion by Wednesday morning, quickly pushing south of the area. High temperatures in the south will occur early in the morning with falling temperatures while locations along the I-75 corridor may be able to achieve some late afternoon warming. With that said, lowered high temperatures from Lorain to Cleveland to Erie where highs may not reach 60 degrees with flow off the lake. Overall highs temperatures on Wednesday will range from 20-28 degrees cooler than what was experienced on Tuesday. Showers will be limited to the far south by afternoon with diminishing trends. Any clearing is likely to be late in the day. The cool airmass will remain for Thursday with a brisk wind off Lake Erie.

KEY MESSAGE 3... Long range models are coming into better agreement late this week. An upper level trough will move east of the Rocky Mountains with shortwave energy lifting north through the Ohio Valley. Moisture streaming north results in overrunning across Ohio which expands into northern Ohio during the afternoon and evening on Friday. This is expected to be a healthy push of rain as the warm front lifts north into Saturday. Temperatures on Friday will still be cooler in the 60s, before hopefully trending warmer into the 70s on Saturday. The QPF forecast from Friday through Saturday ranges from three quarters of an inch to an inch and a half. The rain may become more intermittent by Saturday afternoon but scattered showers and thunderstorms will be possible into Sunday. Although timing varies between models, eventually the trough will lift northeast through the Great Lakes Region with drier air arriving from the west and reducing potential for showers and storms in the late Sunday-Monday time frame.

AVIATION /12Z Tuesday THROUGH Saturday/

Scattered showers are ongoing this morning across parts of the area. There may be some brief restrictions and isolated lightning with this activity. Still expecting several hours of dry and VFR conditions later this morning and this afternoon before another round of convection this evening ahead of a cold front. Am expecting thunderstorms to impact most terminals this evening, with a brief period of vsby restrictions and potential for pockets of strong wind gusts over 40kt with the stronger storms. Still a bit of uncertainty with this later round of storms if shower activity earlier in the day is more significant or prolonged than expected, but still leaning towards the evening round of storms being the main show with this set of TAFs. Showers linger through most of tonight as the cold front crosses from northwest to southeast but with diminishing thunderstorm potential. Low MVFR to even some IFR ceilings likely arrive early Wednesday behind the cold front.

Winds increase to 10-20kt with gusts 25-30kt later this morning and this afternoon. Winds shift north-northwest behind the cold front late tonight into early Wednesday.

Outlook...Non-VFR continues into Wednesday in lower ceilings and possibly rain showers. Non-VFR possible in showers Friday into Saturday.

MARINE

South-southwest winds continue until a cold front crosses the lake overnight tonight. Winds will generally be in the 10-20kt range, with gusts in the nearshore waters of 25-30kt likely this afternoon. Will go with a Small Craft Advisory from Erie County OH points west where winds will be gustiest...not quite as gusty farther east, though still on the breezy side. Waves of 1-3 feet in the nearshore will increase to 2-4 feet in the open waters today. Thunderstorms ahead of the cold front late this afternoon and evening may produce strong wind gusts over 35kt and locally up to 50kt over the lake. Winds whip around to the north- northeast late tonight into Wednesday at 10-17kt behind the cold front, keeping 1-3 foot waves going. Winds increase to 15-20kt and gradually turn more northeasterly into Thursday and easterly into Friday as strong high pressure passes north and northeast of the lake. East-northeast winds often perform well in these types of setups and have continued to inch up in the forecast, and a period of small craft/beach hazards headlines is looking increasingly likely for at least some of the nearshore waters late this week.

CLIMATE

A record high temperature occurred at Erie, Pennsylvania on Monday. High temperatures today will approach record values at some locations again. The following are the records for May 19.

Date Toledo Mansfield Cleveland Akron Youngstown Erie 05-19 92(1996) 88(1964) 88(1998) 91(1911) 89(1934) 90(1996)

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for LEZ142>144.