textproduct: Cleveland

WHAT HAS CHANGED

Issued a Heat Advisory for all counties in Ohio as hot and humid conditions persist.

KEY MESSAGES

1) Scattered showers and thunderstorms continue through Friday before a cold front pushes across the region on Friday. Precipitation chances return as another cold front moves through the region on Sunday.

2) Hot and humid conditions ahead of the cold front with little overnight relief anticipated. Cooler weather behind a cold front Friday into the weekend.

DISCUSSION

KEY MESSAGE 1... Warm and unstable air mass remains in place under a mid/upper level ridge. Some remnant showers and elevated thunderstorms will glide east across the region through this morning, but expecting most of the daytime hours to be dry for a majority of the forecast area. Can't rule out pop up showers and thunderstorms, particularly in southeastern zones, this afternoon and evening. The main show comes later this evening as a decaying MCS will track east towards western zones. Most hi-res CAMs have the MCS petering out as it reaches the I-75 corridor tonight between 11 PM Thursday and 1 AM Friday. SPC does have the entire area under a Marginal Risk (Level 1 of 5) and the I-75 corridor under a Slight Risk (Level 2 of 5) for severe weather. The primary severe weather hazard will be damaging wind gusts with a secondary hazard of large hail, particularly in the Slight Risk area.

The MCS will continue to weaken and eventually dissipate as it pushes east across the forecast area during the overnight hours tonight. Storms may reinvigorate along the Ohio/Pennsylvania border Friday afternoon. SPC has pulled our entire area out of any severe weather outlook for Friday as storms will likely develop just east of our CWA border. Dry weather is expected for the remainder of Friday into Saturday as high pressure builds overhead behind a surface cold front. Another cold front will sink south across the region on Sunday bringing increased chances for showers and thunderstorms to end the weekend and begin next week.

KEY MESSAGE 2... Another day of very hot and humid conditions before the aforementioned cold front glides east on Friday. Have issued a Heat Advisory from noon to 8 PM for all Ohio counties in the CWA. Peak heat index values will reach 100F this afternoon as high temperatures rise into the upper 80s to low 90s coupled with dew points in the low 70s. Peak heat indices will largely range between 95-100F this afternoon. Some spots in the advisory may not "reach" the 100F criteria, but heat-related impacts remain possible.

Temperatures fall to the upper 70s to low 80s on Friday behind the warm front. High pressure and southerly return flow on Saturday will allow for highs to warm into the mid to upper 80s. Cooler behind Sunday's cold front with highs in the mid 70s through the middle of next week.

AVIATION /12Z Thursday THROUGH Monday/

Scattered showers and thunderstorms will likely develop along the remnant boundary of a decayed MCS this morning into this afternoon. There's still quite a bit of uncertainty on precipitation placement/coverage, but at this point it appears that the best chance of showers/storms will be at KMFD/KCAK/KYNG/KERI late this morning into this afternoon. KCLE could experience a brief period of showers/storms before 18Z. After a break in precipitation this evening, a decaying complex of thunderstorms will move east into the area. The strength and longevity of storms will likely rely on how unstable the atmosphere is over the region (which will depend on how things pan out this morning/afternoon), but at this point it looks like the best chance of showers/storms will be at KTOL/KFDY after midnight with decreasing chances farther east overnight.

As far as flight conditions go, VFR conditions are expected outside of precip through tonight. Any showers/storms will be capable of producing non-VFR conditions in lower ceilings and reduced visibilities in moderate to heavy rainfall. Low-end VFR ceilings are likely and MVFR ceilings are possible early Friday morning.

Winds will be out of the southwest at 8 to 14 knots with periodic gusts to 15 to 25 knots through the TAF period. As mentioned above, wind gusts will likely be stronger in thunderstorms. LLWS will need to be considered if gusts struggle to mix to the surface early Friday morning.

Outlook... Non-VFR possible in scattered showers and thunderstorms Sunday.

MARINE

Southwest winds to 10 to 15 knots are expected on Lake Erie this morning with winds briefly diminishing this afternoon into this evening. Southwest winds will increase to 10 to 20 knots as a cold front approaches from the west after midnight tonight. The highest waves will likely be focused offshore so Small Craft Advisories likely won't be needed unless winds trend a bit higher, but there is be a moderate risk of rip currents from Cuyahoga County east as winds become a bit more westerly early Friday. Periodic thunderstorms are possible through early Friday and winds and waves could be higher in thunderstorms.

Winds will diminish Friday afternoon and expect relatively light west/southwest flow through the daytime hours Saturday before southwest winds increase to 15 to 20 knots ahead of an approaching cold front late Saturday into Sunday. Small Craft Advisories and Beach Hazards Statements may be needed as elevated winds shift onshore behind the cold front Sunday afternoon/evening.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Heat Advisory from noon today to 8 PM EDT this evening for OHZ003-006>014-017>023-027>033-036>038-047-089. PA...None. MARINE...None.