textproduct: Cleveland

WHAT HAS CHANGED

No significant changes to the forecast and trends for this cycle.

KEY MESSAGES

1) Heat and humidity increase slightly for today and Thursday, and linger through Friday.

2) Upper level ridge providing the heat will break down and retreat back south, leaving the region in a more zonal flow pattern and returning to convective chances beginning Friday.

DISCUSSION

KEY MESSAGE 1... Upper ridge now firmly anchored over the Ohio Valley and will continue to see heat build into the region. Dewpoints are in the 70s and will largely stay there the next couple of days, or at the very least the upper 60s. 850mb temperatures will push the mid 20s. With another day of ground/surface drying and these slightly higher 850mb temperatures, thinking is that upper 90s will be more prevalent today and Thursday as well. Still have some breezier conditions, especially out in the western zones, and overall, will keep max temperatures across the CWA under 100F. Last day of the extreme eat looks to be Friday, although there are signs pointing to the upper level ridge possibly breaking down somewhat on Friday. Going with mainly mid 90s for Friday, but could see it more like lower 90s depending on what the upper level ridge does. No changes to the warnings and advisories that are already in place.

KEY MESSAGE 2... A bit cooler into the weekend in a more zonal flow aloft where temperatures will be more in the upper 80s Saturday into Sunday. But, as has been mentioned in previous forecasts, convective chances likely to return to the region. Elevated instability exists currently, and will continue into the weekend. Column RH is severely lacking while in this upper level ridge, but expect moisture to increase this weekend in the zonal flow aloft. Surface based instability would likely have to contend with a boundary layer cap, not unexpected given the heat, so forcing mechanisms would have to be above this cap. In the end, high end POPs for the convective chances Friday through the weekend, and will have to evaluate severe potential as Friday nears.

AVIATION /12Z Wednesday THROUGH Sunday/

VFR conditions are expected today and tonight. Some diurnal cumulus (4-5 kft) will develop this afternoon, mainly closer to the lakeshore in NE OH and NW PA. Winds will remain southwest through the period to 10 kts with a couple spots having 20 kts during the afternoon hours.

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

MARINE

With high pressure to the south, pleasant marine conditions are expected with southwest flow averaging 10 knots through the period. There could be a lake breeze that develops east of Cleveland each afternoon, which would allow for minor shifts in wind direction and brief 2 ft waves that would be short-lived. Shower and thunderstorm activity will return starting on Thursday night into the weekend.

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 07-01 98(1931) 98(1931) 95(2002) 97(1931) 96(1931) 94(2018) 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 Thursday for OHZ003- 006>014-017>023-027>033-036>038-047-089. PA...Heat Advisory until 8 PM EDT Thursday for PAZ001>003. MARINE...None.