textproduct: Cleveland

WHAT HAS CHANGED

Some additional shower activity has formed early this morning with fog and low stratus quickly filling in behind these showers. The storms threats this afternoon and again during the middle of the week remain unchanged.

KEY MESSAGES

1) Showers and thunderstorms are expected ahead of a cold front this afternoon. There is potential for strong to severe storms with gusty to damaging winds as the main threat.

2) Warm and humid weather returns for the middle of the week, bringing additional shower and storm chances starting on Tuesday night.

DISCUSSION

KEY MESSAGE 1... Some showers have developed over the southeastern portion of the forecast area early this morning with a piece of mid-level energy moving through the Upper Ohio River Valley, tapping into a moist environment. These showers should exit over the next couple of hours. Immediately behind these showers, conditions are clearing and allowing for a mix of fog and low stratus to form across the area. This should only continue to build overnight and become more locally dense with time. There will likely need to be at least a Special Weather Statement for the visibility at some point this morning, but a Dense Fog Advisory cannot be ruled out.

After some recovery during the late morning hours, the main concern of the day will be additional showers and storms developing ahead of a cold front. By early afternoon, temperatures should be in the 80s with dew points in the upper 60s/lower 70s. This will present enough of a warm, moist air mass to support storm development with modest MLCAPE values. With the storms and cold front, there will be support with the right entrance region of an upper level jet and 0-6 km bulk shear values will be around 40 kts, which will allow for some organization of storm activity. The main concerns with storms would be gusty to damaging wind gusts, although some hail could be possible with the strongest storms. The limiting factor for storms within the forecast area will be real estate. The front will be moving from northwest to southeast and convective initiation will be over the local area. By the time storms become strong enough to merit any wind or hail hazards, they may be south of I-90 and east of I-71 with very little of the forecast area left to work with.

KEY MESSAGE 2... The middle of the week forecast continues to be unsettled as a pseudo-cold front will approach the region from the northwest as the upper ridge over/south of the area will break down a bit. This front will generate a round of showers and storms on Tuesday night, as some mid- and upper-level energy will be allowed into the lower Great Lakes region. The frontal boundary will stall out over the area and the local area will be between a trough to the north and a ridge to the south. With warm and humid conditions over the region supplied by the ridge to the south, expect scattered shower and storm chances through at least Thursday with an unsettled pattern in place. One note of early concern is that there will be the west-east oriented surface boundary over the region with zonal west-east flow aloft that could favor repeated rounds of storms over the same areas, which could pose heavy rain and flooding concerns, depending on how things end up later this week.

AVIATION /06Z Sunday THROUGH Thursday/

VFR conditions are beginning to deteriorate as patchy BR/FG has developed and as an area of showers pushes eastward across southeastern terminals. Expect fairly widespread IFR to LIFR conditions, primarily across inland terminals, in fog and mist. Closer to the lakeshore, expect MVFR to IFR conditions in BR. Fog should begin to lift near daybreak this morning, though lingering non- VFR stratus will persist into the late morning hours.

A line of showers and storms will develop along and east of I-71 this afternoon and push east through this evening. Have maintained PROB30 groups along a line from KMFD/KCLE and terminals to the east. Non-VFR visibilities will be possible in any storm that moves overhead a TAF site.

Light and variable winds through the overnight will become westerly to northwesterly this morning at 5-10 knots. Winds will briefly increase to 10-15 knots with gusts to 20 knots this afternoon.

Outlook...Non-VFR possible in scattered showers/storms Tuesday into Wednesday.

MARINE

A cold front will approach the lake today. Ahead of the front, offshore flow will remain through the afternoon hours. The front will cross the lake by evening with a quick shift to strong northwest flow of 15 to 20 kts with cold advective flow. This will allow for waves to build to 3 to 6 ft across the nearshore and Small Craft Advisories and Beach Hazards Statements have been issued for tonight into Monday morning.

High pressure will build over the lake for Monday and winds will decrease as flow shifts to the east then south. A warm front will lift across the lake by Tuesday and stronger southerly flow will move over the lake. A front will approach the lake on Tuesday night and wash out south of the lake for the middle of the week. With the frontal passage, there should be onshore flow again for Wednesday and Thursday. However, the flow should be weaker than tonight's cold front since the incoming air mass isn't very different.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement from this evening through late tonight for OHZ003-007. Beach Hazards Statement from this evening through Monday morning for OHZ009>012-089. PA...Beach Hazards Statement from this evening through Monday morning for PAZ001. MARINE...Small Craft Advisory from 6 PM this evening to 4 AM EDT Monday for LEZ142-143. Small Craft Advisory from 6 PM this evening to 10 AM EDT Monday for LEZ144>149.