textproduct: Cleveland

WHAT HAS CHANGED

Minor adjustments based on latest guidance, though overall we're still looking at late Friday into early Saturday followed by later Monday into Tuesday for the main upcoming rain chances.

KEY MESSAGES

1) Showers and some thunderstorms are likely later Friday into early Saturday. The overall concern for severe weather and heavy rain is low, with a Marginal Risk (level 1 of 5) for isolated damaging winds in place across Northwest OH for late Friday.

2) After quiet weather to end the weekend, the next low pressure brings shower and storm potential late Monday into Tuesday.

DISCUSSION

KEY MESSAGE 1... A front remains draped across the area this afternoon, extending from near the western lakeshore to just south of Cleveland to just north of Youngstown. It has mainly been another dry, warm, mostly sunny day though we are beginning to see a few showers/storms developing in the vicinity of the Central Highlands. This mainly isolated activity remains possible through the early evening along and southwest of the front. Not expecting any severe weather this evening, though enough for a slight chance mention in the forecast for parts of the area. After any pop-up showers/storms dissipate, it will turn into a dry night tonight with lows mainly settling into the mid to upper 50s, except upper 40s/lower 50s across far Northeast OH and Northwest PA. Some limited fog isn't ruled out in typical valley locations very late tonight into early Friday, though should be quite sparse.

A gradually weakening shortwave, associated surface low, and trailing cold front will move east across the southern Great Lakes/Upper Ohio Valley late Friday into early Saturday, bringing more widespread shower and storm activity. Shortwave ridging will be overhead to start on Friday before getting flattened and exiting east into Friday night. The front (likely enhanced by a lake breeze during the afternoon) will lift north of most of the area, but will likely get hung up across the northeast corner of OH and Erie County PA. So while most of the area will enjoy a mainly dry, warm Friday in the warm sector, Erie will likely stay in the 60s. A few showers/storms may also develop near that front across the northeast corner of the area Friday afternoon. Elsewhere, most of the day Friday should remain rain-free with highs ranging from the mid 70s to near 80.

Greater forcing pushes in from the west into Friday night as the shortwave and cold front move in from the west and flattens any remaining ridging aloft. This will bring more organized shower and storm potential in from the west. There's good agreement in an organized band of showers/storms moving into Northwest OH late Friday afternoon or evening from the west. Activity will likely gradually weaken as it moves across the area Friday night, due to the shortwave itself slowly weakening and nocturnal stabilization. Still, everyone should see some rain Friday night with the greatest confidence in thunder and higher overall QPF amounts across Northwest OH. Drier weather gradually spreads in from west to east late Friday night into Saturday. The shortwave and surface low will slow while departing, so far Northeast OH and Northwest PA may end up rather cloudy/ somewhat damp for most of Saturday. Locations farther west should see drier and gradually sunnier weather work in sooner on Saturday. Lows Friday night will range from the upper 40s to mid 50s. It will trend cooler behind the cold front for Saturday, with highs expected to range from the 50s near the lake across Northeast OH and Northwest PA to the mid-upper 60s well inland.

The potential for severe weather and heavy rain with this system remain limited. Average QPF amounts of generally 0.30-0.60" are in the forecast, with locally an inch not ruled out if localized training or repeating showers/storms occur. In terms of severe potential, low-level inverted-v soundings Friday afternoon/early evening and modest flow aloft could support gusty outflow winds with any more-organized storms pushing into Northwest OH. However, the overall thermodynamics and kinematics are very marginal (at best) for severe weather, so am not expecting an organized threat. The SPC Marginal Risk (level 1/5) for damaging winds across western portions of our area should sufficiently cover the severe weather threat.

KEY MESSAGE 2... Some clouds and lingering light showers may persist across Northwest PA into Saturday night...otherwise, dry weather is expected Saturday night through Monday morning as high pressure slides across the Great Lakes/Northeast and southeastern Canada. It will remain cooler for the second half of the weekend, with lows in the 40s and highs in the 60s. Fairly potent (990-995mb) low pressure will lift into the Upper Great Lakes Monday night into Tuesday. A warm front will lift through late Monday or Monday night ahead of this low, followed quickly by an occluding cold front in the vicinity of Tuesday morning. Much of Monday looks dry, before shower and storm chances move in from the west late Monday or Monday night. Rain chances likely linger into Tuesday before exiting east. As implied by the strength of the low this system will have some better dynamics with it, to the point where it likely will produce organized severe weather to our west on Monday. Impression at this time is that the timing of the front earlier on Tuesday should limit severe weather and heavy rain potential locally, though will still need to keep an eye on that overall evolution as we get closer.

It is rather uncertain how dry we end up for Wednesday and Thursday, as the front may stall across the Upper Ohio Valley behind the early week system. If the front does stall closer to the local area, some rain may return later in the week as indicated by some 30% mentions in the forecast for Wednesday and Thursday. As that 30% also implies, there's a very realistic scenario in which the front sweeps far enough south to simply dry out. Either way, we should trend a bit cooler for Wednesday and Thursday with overall low impact wx.

AVIATION /18Z Thursday THROUGH Tuesday/

VFR will prevail through the TAF cycle as high pressure gradually weakens and departs to the east. This will lead to slowly increasing cirrus tonight and Friday morning.

A lake breeze will continue to impact KCLE and KERI this afternoon and evening with NE winds of 5-10 knots before turning light southerly tonight. The lake breeze will quickly redevelop at KERI by mid Friday morning and could impact KCLE again by afternoon. Otherwise, SW winds will average 5-10 knots through the TAF period.

Outlook...Periodic showers and thunderstorms with non-VFR possible Friday afternoon through Saturday morning and on Monday.

MARINE

Winds and waves are still expected to stay below marine headline criteria through early next week due to relatively weak pressure gradients. Light E to SE winds tonight will quickly turn ENE at 10-20 knots Friday as a warm front stalls over the lake. These will be the strongest winds of the next 5 days. The winds will gradually turn N at 5-10 knots Friday night as a weak low crosses the lake, with N to NE winds averaging 5-15 knots persisting Saturday and Sunday as high pressure builds into the Great Lakes. E to SE winds will gradually increase Monday as a warm front approaches the lake, turning W to SW by Tuesday as a cold front crosses the lake.

CLE WATCHES/WARNINGS/ADVISORIES

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