textproduct: Cleveland

WHAT HAS CHANGED

Forecast remains on track, overall, including periods of unsettled weather through tomorrow.

KEY MESSAGES

1.) Below-average temperatures, overall, are expected through Thursday night.

2.) Unsettled weather is expected today through Thursday.

3.) A warming trend is expected this Friday through Monday.

DISCUSSION

KEY MESSAGE 1... Aloft, a longwave trough and embedded shortwave disturbances affect our region through Thursday as the longwave trough axis moves from the western Great Lakes early this morning to near eastern Lake Ontario and the Delmarva Peninsula by sunset Thursday evening. The attendant surface low should wobble ESE'ward from northeastern Lower MI early this morning to near Lake Champlain by sunset Thursday evening. This low track should allow a surface cold front to sweep E'ward across our CWA between about daybreak this morning and this early evening. Behind the cold front, a surface ridge builds from the Upper Midwest and vicinity through Thursday night, while the mid/upper-level portions of this ridge should begin to build from the west by Thursday night. Today's daytime highs are expected to reach the upper 50's to mid 60's as abundant cloud cover associated with the low pressure system and the cold front passage result in muted daytime heating. Low-level CAA behind the cold front will contribute to lows reaching mainly the 40's around daybreak Thursday and Friday, respectively. However, latest NWP model trends continue to suggest clearer sky and resulting greater nocturnal cooling will contribute to lows reaching the upper 30's in portions of interior NE OH around daybreak Friday. In between, daytime highs on Thursday should reach only the upper 40's to mid 50's in NW PA and the 50's to mid 60's in northern OH.

KEY MESSAGE 2... Periods of rain, steady to heavy at times, are expected to end from west to east between about daybreak this morning and this early evening given the expected progression of the above-mentioned cold front and the eastward translation of the low pressure system's warm conveyor belt undergoing moist isentropic ascent aloft. Occasional thunderstorms are possible through this early evening as the aforementioned lifting mechanisms release primarily weak CAPE, including elevated CAPE.

During tonight into early Thursday, lake-enhanced/effect rain is expected to occur over and generally southeast of Lake Erie, especially central and eastern portions of the lake, as a primarily NW'erly mean low-level flow of sufficiently-cold/moist air becomes established over/downwind of the ~12C lake, at least weak lake-induced CAPE forms, and the seeder-feeder process occurs at times amidst a sufficiently-cold/moist low/mid-level atmospheric column and isentropic ascent ahead of shortwave trough axes embedded in the aforementioned longwave trough aloft. Between daybreak and nightfall on Thursday, lingering lake-effect/enhanced rain showers should end from west to east and give way to dry weather region-wide by Thursday night as lake- induced CAPE wanes amidst low/mid-level dry air advection and a lowering subsidence inversion accompanying the ridge that will build from the west.

KEY MESSAGE 3... A warming trend is expected this Friday through Monday night as our region becomes located within a net low-level WAA regime along the western flank of the aforementioned ridge at the surface and aloft. Moderating temperatures should include daytime highs in the 60's to lower 70's on Friday followed by daytime highs in the 80's to near 90F on Monday. Periodic showers and thunderstorms are expected, especially overnight Friday night through Monday night, as a low-level return flow of warm, moist, and at least weakly-unstable air originating over the Gulf becomes established and multiple shortwave troughs embedded in the primarily SW'erly flow aloft and attendant surface trough axes traverse our region.

Slightly cooler and cloudier weather is expected Tuesday and Wednesday of next week as the ridge continues to exit slowly E'ward, a trough aloft approaches from the west, and a cold front approaches slowly from the northwest before potentially drifting SE'ward across our region Tuesday night through Wednesday. The potential for periodic showers and thunderstorms should increase along and ahead of the cold front as the low- level return flow of warm, humid, and at least weakly-unstable air from the Gulf persists in the warm sector and shortwave disturbances embedded in mainly SW'erly flow aloft and attendant surface trough axes continue to traverse our region.

AVIATION /12Z Wednesday THROUGH Sunday/

Mainly dry and VFR conditions are expected the rest of this morning through the afternoon, but another trough rotating across Lake Erie will generate scattered showers this evening into tonight, mainly affecting KCLE, KMFD, KCAK, KYNG, and KERI. These showers will bring longer periods of MVFR/IFR. The showers will gradually move out toward the end of the TAF cycle.

S to SW winds of 10-15 knots will occasionally gust to 20-25 knots this morning before turning WNW at 15-25 knots by late morning through the afternoon behind a cold front. WNW winds will become NW and decrease to 5-10 knots late this evening and tonight.

Outlook...Non-VFR possible with lingering rain and low ceilings through Thursday. Non-VFR may return in isolated to scattered rain showers and thunderstorms Saturday and Sunday.

MARINE

Hazardous conditions will be found across Lake Erie through Thursday as an unseasonably deep mid/upper trough swings across the Great Lakes region. SW winds of 15-25 knots this morning will turn WNW at 15-25 knots this afternoon. After a lull tonight with NW winds dropping to 10-15 knots, NW winds will increase to 15-25 knots again Thursday morning before decreasing in the afternoon. This will support 3 to 5 foot waves today and again early Thursday, with the highest waves in the central and eastern basins.

Quieter conditions are then expected Thursday night through the weekend, with light and variable winds Thursday night becoming S at 5-15 knots Friday and SW at 10-15 knots by Saturday. Winds will then turn E to SE and decrease to 5-10 knots Saturday night and Sunday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory until noon EDT Thursday for LEZ142>149.