textproduct: Cleveland

WHAT HAS CHANGED

The Enhanced Risk for today has been expanded westward to include most of the local area. Damaging wind gusts remain the main hazard with storms today. Otherwise, the forecast remains on track.

KEY MESSAGES

1) Showers and thunderstorms are expected this afternoon into this evening. Scattered storms will could be strong to severe with damaging winds being the primary hazard.

2) Additional showers and thunderstorms are likely late Monday and Tuesday. Storms may be strong to severe, primarily on Tuesday.

3) Today will be the last day with hot temperatures before temperatures cool down Sunday.

DISCUSSION

UPDATE... Tweaked POPS this morning to account for the widely scattered convection in the warm sector. This appears to be tied to a weak wind shift or outflow boundary, and expect it to push largely S and E of the area by 15 to 16Z. No severe weather and minimal lightning is anticipated with this activity. Mainly dry conditions will otherwise dominate late this morning through mid afternoon until convection starts to develop ahead of the cold front, with the main show likely to be between 4 and 9 PM. See Key Message 1 below for details.

KEY MESSAGE 1... A warm front will lift east of the area this morning, pushing any lingering smoke to the east. From there, the CWA will be in the warm sector as a cold front approaches from the northwest. Isolated showers/thunderstorms can't be ruled out through this morning, although confidence in the coverage/placement is low. Showers and thunderstorms will develop with a pre-frontal trough this afternoon before pushing southeast across the CWA into the evening.

There's still potential for severe weather this afternoon into this evening (roughly 2-3 PM through about 9 PM) given the unstable and moist air mass in place across the region. MLCAPE values of 2500- 3000+ J/kg will be in place during peak diurnal heating and some mid- level dry air (and DCAPE values of around 800-1000 J/kg) will contribute to a damaging wind gust threat, which may be scattered to widespread depending on how organized storms become. Effective bulk shear will increase to 30 to 40 knots as the cold front advances into the region which will allow any initial cellular convection to congeal into clusters/line segments. A few tornadoes can't be ruled out across portions of NE OH/NW PA, where the wind field and low level shear (albeit marginal) will be a bit more favorable. Isolated instances of large hail can't be ruled out, primarily in storms with taller/rotating updrafts. In summary, damaging wind gusts are definitely the most likely/widespread hazard with tornadoes being a secondary hazard. An Enhanced Risk (Level 3 of 5) of severe weather is in place across most of the area.

Torrential rainfall rates are likely in storms given PWAT values up to 2 inches, however storm motion will be relatively fast which will help mitigate the flash flood risk. There may be ponding/minor flooding in poor drainage/urban areas and around the most responsive creeks/streams, but overall the flash flood risk is low.

Another round of showers and isolated storms may push off of Lake Erie with the cold front later this evening, but the atmosphere will be worked over so do not anticipate severe weather. Dry weather will return for Sunday.

KEY MESSAGE 2... High pressure will produce dry weather through at least early Monday before shower and thunderstorm chances return as the next system moves across the region late Monday through Tuesday. There's still quite a bit of uncertainty with the trajectory and timing of a developing upper level low to the north of the area during this time, which will impact storm placement/timing. There will likely be sufficient forcing for organized showers and thunderstorms and possibly severe thunderstorms at some point on Tuesday (likely during the day), although confidence in instability is low this far out.

KEY MESSAGE 3... Today will feature one last day of well above normal temperatures before cooler temps arrive behind the cold front Sunday. Highs will be in the 80s and lower 90s with the hottest temps expected across NW OH and in urban areas. Dew points will be in the upper 60s and lower 70s and as a result heat index values will be in the 90s. Apparent temps may attempt to briefly flirt with 100 degrees in a few spots along/west of I-71, although confidence in Heat Advisory criteria being met is low due to potential for showers/thunderstorms during peak diurnal heating. Sunday will feel much different with highs in the 70s to around 80 degrees and Sunday night's lows falling into the lower 60s and 50s. Temps briefly warm to around normal Monday/Tuesday, but daytime temps in the 70s will return for mid to late week.

AVIATION /12Z Saturday THROUGH Wednesday/

Mixed-bag of VFR, MVFR, and IFR across the TAF sites this morning, associated with residual wildfire haze and low ceilings. Anticipate improvement to VFR over the next several hours as the haze/low ceilings exit northeast of the area.

Attention then turns towards this afternoon and evening as showers and thunderstorms develop ahead of a cold front, potentially impacting all TAF sites with a brief window of lower vsbys and gusty to strong winds. Highest confidence in thunderstorm coverage and the potential for wind gusts to exceed 40 knots generally resides at MFD and east, with lower confidence further west at TOL/FDY. Additional scattered showers and perhaps a thunderstorm or two are possible with the cold front later in the evening as it sweeps south through the area.

Winds are generally out of the southwest this morning, 7 to 10 knots. Winds will increase and gradually favor a southwest to west direction into this afternoon, 10 to 15 knots with periodic gusts of 20 to 25 knots. Winds will abruptly shift towards the north behind the cold front later this evening and overnight, around 10 knots.

Outlook...Non-VFR possible with haze/smoke on Sunday and Monday. Non-VFR becoming more likely in showers and thunderstorms Monday night through Tuesday. Some thunderstorms Tuesday afternoon and evening may contain strong wind gusts. Residual non-VFR possible on Wednesday on rain showers across the eastern half of the area.

MARINE

Rough marine conditions will arrive across Lake Erie today as southwest winds of 15 to 25 knots develop ahead of a cold front. Winds will shift towards the north behind the front later this evening and overnight, 15 to 20 knots, before diminishing to less than 10 knots by Sunday afternoon. In this package, have extended the Small Craft and Beach Hazards for the central basin, and added a couple of zones west towards the Islands, mainly for the onshore flow later this evening and overnight. Another period for rough marine conditions will arrive on Tuesday as southwest winds of 15 to 25 knots develop ahead of a cold front. Will likely need another round of marine headlines Tuesday through Wednesday as winds shift towards the northwest behind the cold front, around 20 knots.

Strong thunderstorm wind gusts are expected across Lake Erie this afternoon and evening ahead of a cold front.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement from this evening through Sunday morning for OHZ009-010. Beach Hazards Statement through Sunday morning for OHZ011-012- 089. PA...Beach Hazards Statement through this evening for PAZ001. MARINE...Small Craft Advisory from 10 PM this evening to 8 AM EDT Sunday for LEZ144-145. Small Craft Advisory until 8 AM EDT Sunday for LEZ146>148. Small Craft Advisory until 10 PM EDT this evening for LEZ149.