textproduct: Cleveland

WHAT HAS CHANGED

Patchy dense fog is possible through sunrise this morning. The potential for localized heavy rainfall and isolated flash flooding has slightly increased for today as well.

KEY MESSAGES

1) Periodic showers and thunderstorms will continue through Monday, especially in the afternoon and evening hours. Localized heavy rainfall and isolated flash flooding may be possible today.

2) Temperatures will return back to near average today through Tuesday, before becoming slightly above normal towards mid to late week.

DISCUSSION

KEY MESSAGE 1... The main weather concern for today will be a slow moving low pressure system tracking eastward across the Upper Ohio Valley and lower Great Lakes region. First off this morning, there is some patchy dense fog across far NEOH and NWPA. We have a SPS for this patchy fog through sunrise. If trends become widespread, we may have to put out a short-fused dense fog advisory this early morning. High-res model guidance that the weak low pressure system or MCV currently over northern Indiana this morning will slowly track eastward today across northern Ohio and western Pennsylvania. PWAT values are tropical around 1.8 inches. Steering flow is weak around 15 knots or less. We are expected periodic showers and thunderstorms to develop in association with the slow moving MCV east to west across the area. Some localized heavy rainfall and isolated flash flooding may be possible with rainfall rates up to 2.0 inches. Any clusters of stronger convection could potentially support a brief cold pool organization and associated marginal risk for damaging wind gusts. SPC has much of the area highlighted in a day 1 outlook for severe weather due to an isolated damaging wind threat. Most of the convection should weekend and decrease in coverage after sunset this evening.

We will rinse and repeat this diurnally driven convection and rain chances for Monday, especially over the southeastern CWA or areas along and east of I-71. Rain chances will decrease by Tuesday and Wednesday with weak high pressure building into the Ohio Valley. A broad trough will swing through the Great Lakes region late this week and bring a cold front across the area Thursday into Friday. Likely POPs will return into the forecast by the end of the week with scattered showers and storms again.

KEY MESSAGE 2... Due to added cloud cover and higher rain chances today and Monday, temperatures will be closer to seasonable averages for early July. High temperatures will be in the lower to middle 80s today through Tuesday. High temps will increase slightly above average by Wednesday and Thursday into the middle and upper 80s, though heat indices should remain below 100. Seasonable temperatures are expected Friday into the weekend.

AVIATION /12Z Sunday THROUGH Thursday/

Some fog and mist is ongoing at 12z, mainly across eastern OH and into northwestern PA. There are pockets of dense fog, including at YNG. Expect this fog/mist to gradually improve through 14z. Outside of convection conditions should return to mainly VFR through this afternoon. Non-VFR ceilings and visibility may return to some sites tonight.

Main focus and challenge with this set of TAFs remains shower and thunderstorm potential. A batch of showers and storms ahead of an area of weak low pressure is ongoing across Northwest OH and southeast MI as of 12z, with impacts mainly confined to TOL but perhaps clipping MFD and CLE before 15z too. This weak low will drift east-southeast into northern Ohio along a slowly sagging cold front through the afternoon. We may see a brief break in activity later this morning as the current batch shifts out over the lake and into Canada, with the low and front expected to focus another round of afternoon and evening showers and storms. Impacts are most likely at TOL, FDY, MFD, CAK and perhaps YNG this afternoon and early evening near and south of the front, with lower potential at CLE. Thunderstorm potential decreases this evening, though some showers may linger tonight.

Light and variable but mainly southerly winds early this morning will gradually shift more northeasterly through the day today as the front gradually sags across the area. Winds will remain under 10kt outside of any convection today, with a few gusts over 30kt possible with any stronger storms.

Outlook...Non-VFR with occasional showers and thunderstorms possible through Tuesday afternoon. Scattered thunderstorms are also possible Thursday afternoon.

MARINE

Northeast winds will gradually become established across the lake today as low pressure approaches from the west and as a cold front pushes south of the lake. These northeast winds will increase to 10-20kt tonight and Monday, gradually weakening Monday night into Tuesday. This will bring a period of 1 to 3 foot waves tonight through parts of Tuesday, with potential for a brief period or two of 4 footers mainly between the Islands and Willowick when winds push closer to 20kt tonight and Monday. The wind and wave forecast were nudged up a bit higher with this package, and would support marginal Small Craft/Beach Hazards headlines for a few zones in the central basin. Because the forecast is very marginal for a headline and conditions don't ramp up until tonight will hold off on the headlines with this cycle, but they may well be coming today. It will still be on the choppy side on Tuesday though conditions will be on a slow improvement. Expect tranquil conditions on Wednesday, with the next cold front bringing slightly elevated winds and some thunderstorm potential to the lake Thursday into Friday.

CLE WATCHES/WARNINGS/ADVISORIES

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