textproduct: Cleveland

WHAT HAS CHANGED

There is increasing confidence in shower and storm activity moving through the area today. There is also increasing potential for scattered shower and storm activity on Sunday ahead of a cold front, but activity may end up favoring areas southeast.

KEY MESSAGES

1) Shower and thunderstorm activity is expected today and again on Sunday. Some storms may reach strong to severe limits and may bring locally heavy rainfall.

2) Warm, unsettled weather will return to the area on Tuesday night through Thursday with additional showers and storms.

DISCUSSION

KEY MESSAGE 1... Convective activity is moving through the lower Ohio Valley early this morning and will continue to lift north today with a warm front and increasing moisture across the region. Temperatures will return to the 80s this afternoon with the front and surface dew points will return to the lower 70s for most of the area, giving a warm and humid feel. Storms will move through the area through the afternoon with this improved environment in place. There could be a stronger storm possible, especially with some modest MLCAPE across the region and perhaps 30 kts of wind shear with the mid-level shortwave moving through the region. The main concern would be gusty winds. The slightly larger concern could be heavy rainfall with precipitable water values of 1.7-1.8" across the area that indicate that any rainfall could be efficient.

For Sunday, a cold front will approach the region from the northwest. The main question will be how much has the atmosphere recovered over the forecast area before the front arrives. With the bulk of activity occurring this afternoon, there should be about 18-24 hours for the atmosphere to recover and highs on Sunday should be back in the 80s with dew points back in the lower 70s. Therefore, the front should be able to generate some activity over the forecast area before activity blossoms further southeast. There could a bit more organization for strong or even severe storms on Sunday with a better upper trough digging into the Great Lakes region and better right entrance jet energy overhead. The limitation will just be real estate within the forecast area based on the cold front timing and convective initiation on Sunday.

KEY MESSAGE 2... The next weather system will be a cold front that will approach the area Tuesday evening. This front will slow down as it approaches the forecast area and eventually stall overhead on Wednesday. This front will allow for scattered shower and storm chances for Tuesday night through Thursday with the nearby boundary and the warm and humid air mass across the region. Too early to tell if any convective activity will have any severe or flooding threats; however, an east-west oriented boundary over the area with zonal west-east flow aloft may favor repeated rounds of activity over the same areas - The question will just be coverage of storms.

AVIATION /12Z Saturday THROUGH Wednesday/

VFR conditions will deteriorate through the TAF period as a system enters terminals from the southwest. Showers and storms currently spread across southwestern Ohio will lift into Northern Ohio terminals this morning and continue through the bulk of the day today. Confidence in thunder at TAF sites has expanded to include all southern TAF sites (KFDY/KMFD/KCAK/KYNG). Both ceilings and visibilities will fall to MVFR (and possibility IFR) at times as the storms move over terminals. Timed out the best chance for non- VFR through TEMPO groups across terminals with the exception of KTOL where confidence in -RA remains limited. There will likely be a brief window of VFR conditions behind rain showers this evening before widespread MVFR to IFR conditions return tonight into Sunday morning in areas of BR/FG.

Winds 10 knots or less through the TAF window will shift between southeast and southwest today into early Sunday morning.

Outlook...Non-VFR possible in scattered showers/storms Sunday afternoon and evening. Non-VFR again possible in scattered showers/storms Tuesday into Wednesday.

MARINE

A warm front will cross the lake today and allow for modest offshore flow over the basin. A cold front will cross the lake on Sunday and shift winds to the west then northwest. Winds will freshen to 15 to 20 kts with the cold air advection over the basin and waves should build to 3 to 5 ft on Sunday night. Suspect that there will need to be a Small Craft Advisory and Beach Hazards Statement issued for much of the nearshore for Sunday night and lingering into Monday. High pressure will move over the lake on Monday and decrease flow significantly, while winds shift to the east then south. This high pressure system will pass to the east for Tuesday and offshore flow will return once again. A cold front will approach the lake on Tuesday night, shifting winds to the southwest. This boundary should be south of the lake for Wednesday but may be washed out enough to maintain offshore flow over the lake.

CLE WATCHES/WARNINGS/ADVISORIES

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