textproduct: Cleveland

WHAT HAS CHANGED

Forecast remains valid through the middle of next week. No major changes to note.

KEY MESSAGES

1.) Lake-effect/enhanced rain showers end today and below- average air temperatures persist through tonight.

2.) A warming trend is expected this Friday through Tuesday night.

3.) Cooler weather is expected next week Wednesday.

DISCUSSION

KEY MESSAGE 1... A longwave trough aloft exits E'ward through tonight as its axis moves from near western NY and the central Appalachians early this morning to western New England and just offshore the Delmarva Peninsula by daybreak Friday. Otherwise, a surface high pressure ridge continues to build from the western Great Lakes and vicinity, and the portion of this ridge in the mid/upper- levels will begin to build from the west by tonight. This weather pattern evolution at the surface and aloft will maintain net low-level CAA and an unusually-cold air mass across our CWA. Highs are expected to reach only the upper 40's to lower 50's in NW PA and the 50's to mid 60's in northern OH late this afternoon. Tonight's lows are expected to reach mainly the 40's around daybreak Friday. However, clearer sky and resulting greater nocturnal cooling should contribute to lows reaching the upper 30's in portions of interior NE OH.

Light lake-effect/enhanced rain showers will persist over and generally southeast of Lake Erie this morning, especially central and eastern portions of the lake, amidst a primarily NW'erly mean low-level flow of sufficiently-cold/moist air over/downwind of the ~13C lake, weak lake-induced CAPE, and a periodic seeder-feeder process 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. During this afternoon through about sunset this evening, lingering lake-effect/enhanced rain showers are expected to end from west to east and give way to dry weather region-wide for tonight 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 2... A warming trend is expected this Friday through Tuesday night as the ridge at the surface and aloft exits slowly E'ward and our region becomes located within a net low-level WAA regime along the western flank of the ridge. At the surface, a warm front is forecast to sweep N'ward through our region Friday night, while a cold front should approach our CWA from the northwest on Saturday through Saturday night before stalling in vicinity of southern Lower MI and the northern shore of Lake Erie by Sunday. This surface front should then retreat N'ward as a warm front and away from our region by Monday before a a cold front approaches from the northwest by Tuesday night as one frontal surface low moves generally E'ward from the Upper Midwest toward southern QC and is followed by a separate frontal surface low that should undergo lee cyclogenesis east of the CO Rockies and then move NE'ward toward the northern Great Lakes. Moderating temperatures should include daytime highs in the 60's to lower 70's on Friday followed by daytime highs in the mid 80's to near 90F this Monday and Tuesday, respectively.

Periodic showers and thunderstorms are expected overnight Friday night through Tuesday night as a low-level return flow of warm, moist, and at least weakly-unstable air originating over the Gulf becomes established in our region, moist isentropic ascent along the upper-reaches of Friday night's warm front releases at least weak and elevated instability, and multiple shortwave troughs embedded in the primarily SW'erly flow aloft and attendant surface trough axes traverse our CWA Friday night through Tuesday night. Note: strong to severe thunderstorms are possible this Saturday afternoon and evening amidst weak to moderate boundary layer CAPE, steep mid-level lapse rates near 7C/km to 7.5C/km associated with an EML plume that should traverse our region generally from west to east, and moderate to strong deep layer-bulk shear.

KEY MESSAGE 3... During this upcoming Wednesday, the surface cold front should sweep SE'ward across our region as the aforementioned CO low moves generally E'ward from the northern Great Lakes toward southern QC and shortwave disturbances embedded in primarily W'erly flow aloft traverse our CWA. Scattered to numerous showers and thunderstorms should impact northern OH and NW PA as convergence/moist ascent along the cold front and surface trough axes accompanying the shortwave troughs aloft release at least weak boundary layer CAPE in the warm/moist sector. Given the expectation of scattered to widespread precip and greater cloud cover, Wednesday should be cooler and feature daytime highs in mainly the 70's to near 80F.

AVIATION /12Z Thursday THROUGH Monday/

Lake enhanced rain showers are ongoing across Northeast Ohio and Northwest Pennsylvania as a trough resides over the eastern Great Lakes. Ceilings are generally MVFR although a few pockets of IFR are also present in NE Ohio with VFR conditions at TOL/FDY. The precipitation is generally expected to taper off from northwest to southeast through 18Z. Skies will tend to lift to VFR and scatter out from west to east through the afternoon. West to northwest winds will increase after 14Z with gusts to 22-28 knots through the afternoon. Winds will trend more northerly after 23Z and gusts will diminish, becoming increasingly light and variable towards 06Z.

Outlook...Non-VFR becoming more likely in showers and thunderstorms Saturday afternoon and evening. Additional non-VFR possible in scattered showers and thunderstorms Sunday afternoon and evening, though chances are lower.

MARINE

A brisk northwest wind continues on Lake Erie today as the lake resides between high pressure over Lake Michigan and low pressure near Lake Ontario. A Small Craft Advisory remains in effect on the central basin from the Islands to Erie PA where the waves will remain elevated in the 3 to 5 foot range through midday before decreasing. It is possible that areas from Cleveland to Ashtabula may even need to be extended a few more hours.

High pressure will build overhead tonight through Friday with good marine conditions. Southwest winds return on Saturday but overall winds are expected to be 5-15 knots over the weekend. A bigger concern over the weekend will be potential for showers and thunderstorms on the lake and erratic winds associated with those.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory until noon EDT today for LEZ144>149.