textproduct: Cleveland

WHAT HAS CHANGED

The forecast has changed little. Confidence continues to increase that periods of showers and thunderstorms will impact our region Friday night through Saturday night. Some of the storms may be severe Saturday afternoon and evening.

KEY MESSAGES

1.) Dry conditions and a warming trend persist through this Friday.

2.) Periodic showers and thunderstorms are expected this Friday night through Saturday night, along and ahead of a cold front.

3.) Current odds favor dry weather and another gradual warming trend during Sunday through Wednesday of the upcoming week.

DISCUSSION

KEY MESSAGE 1... A ridge at the surface and aloft continues to affect our region through Friday. Aloft, the ridge axis should move from the western Great Lakes and north-central Gulf coast toward the eastern seaboard. Simultaneously, the attendant surface high pressure center should wobble SSE'ward from the south-central Great Lakes to Atlantic waters near the Carolinas. Dry weather persists as stabilizing subsidence accompanying the ridge continues to affect our CWA. On the synoptic-scale, net low-level warm/moist air advection from the Gulf and a warming trend will impact northern OH and NW PA as we become located along the western flank of the low-level portion of the ridge. Late afternoon highs are expected to reach mainly the mid 70's to mid 80's on Thursday and mainly the upper 70's to mid 80's on Friday. The coolest highs are expected along and within several miles of the Lake Erie shore from Lorain County, OH through Erie County, PA on Thursday and from northeastern Cuyahoga County, OH through Erie County, PA on Friday due to lake breeze development each late morning through early evening. Overnight lows should reach mainly the 50's around daybreak Thursday and mainly the 60's around daybreak Friday. KEY MESSAGE 2... Aloft, the aforementioned ridge exits E'ward Friday night through Saturday night and gives way to cyclonic W'erly to NW'erly flow and embedded shortwave disturbances over our region as a primary trough axis moves from near western ON and the Upper Midwest to near New England and the Delmarva Peninsula. At the surface, ridging exits generally SE'ward before a cold front sweeps SE'ward through our region during Saturday evening through the predawn hours of Sunday morning. The front will be preceded by a low-level return flow of warm, humid, and unstable air originating over the Gulf. Behind the front, a surface ridge begins to build from the Upper Great Lakes. Periodic and scattered showers and thunderstorms are expected as weak to moderate instability, including elevated CAPE, is released by the following: low-level convergence/moist ascent along surface trough axes accompanying the shortwave disturbances and along the surface cold front; moist isentropic ascent ahead of the shortwave trough axes and along the upper-reaches of the cold front. Some thunderstorms may become severe this Saturday afternoon into the evening as the warm/moist sector boundary layer destabilizes via peeks of sunshine and daytime heating, and moderate to strong deep-layer bulk shear resides in our region. Periods of torrential rainfall amidst unusually-high PWAT's in the warm/moist sector are expected. However, the flash flood threat still appears to be minimal since W'erly mean mid-level flow should be fairly- strong and not largely-parallel to the front.

Overnight lows should reach the 60's around daybreak Saturday and be followed by late afternoon highs in the upper 70's to mid 80's as abundant cloud cover ahead of the primary trough axis aloft should limit daytime heating. Weak and net low-level CAA behind the cold front should contribute to lows reaching the upper 50's to mid 60's around daybreak Sunday.

KEY MESSAGE 3... Current odds favor dry weather for Sunday through Wednesday of the upcoming week as ridging at the surface and aloft affects our CWA and is accompanied by stabilizing subsidence. At the surface, the high pressure center should wobble generally SE'ward from the northern Great Lakes to near the Delmarva Peninsula, while the ridge axis aloft should move from the Upper Midwest and north-central Gulf coast toward the eastern seaboard. Accordingly, net low-level CAA on Sunday should give way to net low-level WAA by Monday through Wednesday. Late afternoon highs in mainly the mid 70's to lower 80's on Sunday should moderate to mainly the 80's on Wednesday. Overnight lows should moderate from mainly the 50's to lower 60's around daybreak Monday to mainly the lower to mid 60's around daybreak Wednesday.

AVIATION /00Z Thursday THROUGH Monday/

High pressure remains in control, allowing for VFR and mainly clear conditions to continue through the TAF period. Light and variable winds tonight shift southwest and increase to 6-12kt Thursday afternoon. Winds will be a bit more westerly at ERI due to a lake breeze. There is uncertainty regarding if the lake breeze will get to CLE in the afternoon, which would lead to a temporary flip to N-NW winds. The TAF currently maintains the SW winds, but will continue to evaluate in future updates.

Outlook...Scattered thunderstorms with non-VFR likely at times on Saturday, especially during the afternoon and evening.

MARINE

High pressure over the region through Friday will allow for fairly benign marine conditions. Light and variable winds will continue on the lake today and tonight with dry and clear weather. While dry weather will continue through Friday, winds will shift around to the southwest for Thursday and then increase slightly with good afternoon mixing on Friday up to the 10 to 15 kt range. A low pressure system will enter the region for the weekend, bringing some storm chances. Southwest winds will continue on Saturday before a cold front sweeps through on Saturday night, bringing northerly flow to the region for Sunday. No marine headlines are expected at this time.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...None.