textproduct: Cleveland

WHAT HAS CHANGED

No significant changes from the previous forecast.

KEY MESSAGES

1) Showers and thunderstorms will develop ahead of a cold front tonight through Tuesday. Severe storms are possible, though uncertainty remains on timing and coverage.

2) A brief cool-down is expected mid-week, before temperatures return near or slightly above normal by the weekend.

DISCUSSION

KEY MESSAGE 1... An unseasonbly-potent shortwave will track east across the Midwest and Ohio Valley tonight into Tuesday, associated with a broad upper-level trough rotating east through the Upper Great Lakes. At the surface, a warm front will lift northeast across the area tonight, followed by a strong cold front Tuesday night. The latest SPC SWODY2 outlook has much of the area in a slight risk, with a small sliver across the southeast in an enhanced risk for damaging wind gust potential.

The main concern with this system will be the potential for severe storms, given the strong environmental shear profiles, though a large amount of uncertainty remains on both coverage and timing. The latest hires ensemble guidance suggests a nocturnal convective complex may immediately follow the warm front on the nose of a potent 700 mb shortwave Tuesday morning across North- Central Ohio. Redevelopment of this complex of storms is possible by late morning, (around 11 AM) generally along and east of the I-71 corridor, exiting east into Pennsylvania by roughly 2 PM. In this case, any additional severe threat later in the afternoon or evening would be limited. This scenario appears the more likely one, given the overall dynamics of this system. The favored storm mode with this scenario would be a larger mesoscale convective complex with a more widespread damaging wind threat and potentially a few embedded tornadoes.

A second, but lower likelihood, scenario would be that the nocturnal complex mostly dissipates by Tuesday morning, resulting in greater destabilization ahead of the cold front and a slightly later initiation time for thunderstorms, roughly 2 PM, and exiting east of the area by 7 to 8 PM. This scenario would favor more mixed storm modes such as line segments and supercells given the slightly better shear/instability overlap (more of an all-hazards threat, including damaging wind gusts, a few tornadoes, and large hail).

KEY MESSAGE 2... A much cooler air mass will enter the region behind the cold front on Wednesday, with highs falling into the low 70s (and some places upper 60s) on Wednesday, only marginally increasing into the mid-70s by Thursday. By the end of the week into the weekend, a large upper-level ridge will develop across the Southwest CONUS and expand eastward into the Midwest/Great Lakes. Temperatures will return to near or slightly above normal in the mid to upper-80s by Saturday and Sunday.

Mainly dry weather is favored for this period, though shower and thunderstorm chances may begin to increase by late Sunday.

AVIATION /12Z Monday THROUGH Friday/

Other than a brief period of MVFR vsbys in haze due to wildfire smoke early this morning, VFR is expected through late tonight. Patchy smoke will likely stick around through roughly 00Z today, but do not anticipate significant reductions in vsbys during the day today. A weakening complex of thunderstorms will move southeast into the local area after 06Z Tuesday and could reach as far east as KCLE/KMFD by 12Z. Have prevailing showers with PROB30 groups for thunderstorms/MVFR conditions for KTOL/KFDY and PROB30 groups for showers for KCLE/KMFD towards the end of the TAF period. VFR is expected outside of showers and thunderstorms.

Winds will be light and variable early this morning with light south/southwest flow developing by mid to late morning. A lake breeze will allow more northerly winds to 5 to 10 knots develop this afternoon into this evening. South/southwest winds will likely increase overnight with gusts to 20 to 25 knots likely across NW OH and along the lakeshore towards the end of the TAF period.

Outlook...Non-VFR likely in showers and thunderstorms through Tuesday afternoon. Some thunderstorms Tuesday afternoon may contain strong wind gusts. Residual non-VFR possible on Wednesday in rain showers across the eastern half of the area.

MARINE

Calm marine conditions are expected today, but south/southwest winds will begin to increase tonight as a warm front crosses the lake and a cold front approaches from the west. By 8 AM or so Tuesday morning, southwest winds to 15 to 25 knots (strongest winds in the open waters) are expected with waves likely building to 2 to 5 feet in the nearshore waters of the central and eastern basins of the lake. Small Craft Advisories will likely be needed during the day Tuesday and probably through much of Wednesday as flow shifts to the northwest behind the cold front. Winds will diminish Wednesday evening/night and expect much better marine conditions as winds remain below 10 knots Thursday/Friday.

CLE WATCHES/WARNINGS/ADVISORIES

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