textproduct: Cleveland

WHAT HAS CHANGED

There is now an areawide Slight Risk (Level 2 of 5) of severe weather on Friday.

KEY MESSAGES

1) Dangerous heat and humidity persist through the end of the week.

2) Daily chances for showers and thunderstorms return this evening onward.

DISCUSSION

KEY MESSAGE 1... Heat and humidity continue one more day before the ridge of high pressure breaks down. Extreme Heat Warning for all of Ohio and Heat Advisory for Northwest Pennsylvania remain in effect through 8 PM Friday evening. Overnight lows tonight and Friday night will remain in the 70s. Forecast high temperatures on Friday rise into the mid 90s areawide with heat index values of 100-108F. Temperatures will remain warm this weekend, but slightly lower in the upper 80s to lower 90s. Heat index values may top out around 100F on Saturday, but will be largely dependent on coverage of any showers and storms. With the continued heat and limited overnight relief, the majority of the forecast area remains under Extreme HeatRisk (Level 4 of 4). For people without effective cooling, especially heat-sensitive groups, this level of heat can be deadly.

KEY MESSAGE 2... Slight chance to chance PoPs for showers and thunderstorms in the forecast for tonight as a disturbance rides over the top of the ridge. Any precipitation should occur after 8 PM tonight and remain confined to lakeshore zones in Northern Ohio and Northwest Pennsylvania. The SPC has included counties along the lakeshore in their Day 1 Marginal Risk (Level 1 of 5) for severe weather as any stronger thunderstorm that develops may be capable of producing strong to damaging winds.

Chances for showers and thunderstorms should increase tomorrow as the ridge of high pressure exits the region. SPC has upgraded the Day 2 Severe Weather Outlook to a Slight Risk (Level 2 of 5) across the entire area with a primary hazard of damaging wind gusts. Best potential for showers and thunderstorms will occur during evening hours. However, the confidence in exact timing and placement of strong to severe storms remains low at this time given weak forcing aloft. Strong to severe storms will remain possible through the weekend as multiple shortwaves aloft move overhead. SPC has introduced a Marginal Risk (Level 1 of 5) for Saturday. Will hang on to daily PoPs in the slight chance to chance range into early next week.

Given the very moist airmass in place with PWATs of 1.5 to 2 inches any thunderstorm that does develop will be capable of producing locally heavy rainfall. There is a Marginal Risk (Level 1 of 4) for Excessive rainfall both Saturday and Sunday.

AVIATION /18Z Thursday THROUGH Tuesday/

FEW/SCT cumulus clouds around 5 kft will continue this afternoon and are expected again Friday afternoon. Southwest winds around 8-12 knots during the afternoon hours today and tomorrow with lower winds (around 5 knots) tonight. Gusts up to 20 knots are possible during the afternoon.

There is a very low chance for thunderstorms near KERI tonight.

Outlook...Greater potential for scattered storms Friday through Sunday, especially during the afternoon and evening hours each day.

MARINE

Southwest winds around 10-15 knots will persist through the weekend, and wave heights will generally be around a foot or a less in the nearshore zones of Lake Erie, with some potential for 2 ft waves with the effect of the lake breeze during the afternoon. With low pressure moving into the region after Sunday, east to northeast flow on Monday becomes northerly on Tuesday, with winds speeds around 10 knots.

CLIMATE

Very hot and humid weather is expected through Friday. Record warm high temperatures may be challenged. Here are those records for each of our climate stations:

Date Toledo Mansfield Cleveland Akron Youngstown Erie 07-02 98(2011) 97(1931) 97(1954) 98(1931) 98(1931) 94(1963) 07-03 100(1911) 93(2020) 98(1949) 97(1911) 98(1898) 93(1934) 07-04 100(2012) 96(2012) 98(1990) 99(1911) 99(1897) 99(1990)

CLE WATCHES/WARNINGS/ADVISORIES

OH...Extreme Heat Warning until 8 PM EDT Friday for OHZ003-006>014- 017>023-027>033-036>038-047-089. PA...Heat Advisory until 8 PM EDT Friday for PAZ001>003. MARINE...None.