textproduct: Cleveland

WHAT HAS CHANGED

A Marginal Risk for severe weather has been added across Northwest Ohio and Lake Erie for late Thursday.

KEY MESSAGES

1) Tranquil conditions expected until later Thursday.

2) Showers and thunderstorms are expected at times late Thursday through Friday. There is a Marginal Risk (level 1 of 5) for a few storms to produce damaging wind gusts over northwestern portions of the area Thursday evening. Locally heavy rainfall is also possible with some storms late Thursday into Friday.

3) A period of drier weather with limited precipitation chances is expected this weekend into early next week.

DISCUSSION

KEY MESSAGE 1... Brief ridging surface and aloft today into early Thursday. For today, will be on the lookout for patchy fog first thing this morning. A mainly dry and somewhat warm day is expected today with highs mainly in the mid to upper 80s (slightly cooler in the far northeast, perhaps touching 90 in Toledo). Can't rule out a stray shower or storm over the hills of Northwest PA this afternoon, but that should be it. Quiet weather persists tonight as any showers/storms with a weak Ohio Valley shortwave stay to our south. Lows will mainly settle in the 60s with perhaps just a bit of patchy fog in the usual inland valleys overnight.

KEY MESSAGE 2... Unsettled weather returns late Thursday into Friday as a cold front gradually approaches and crosses the area. A good portion of Thursday will remain dry. A shortwave tracking through the upper Ohio Valley will spark scattered showers/storms that may affect far eastern Ohio and inland northwestern PA during the afternoon. Otherwise, convection will likely develop closer to the approaching cold front from lower MI into northern IN during peak heating hours on Thursday, with a shortwave moving across the southern Great Lakes during the afternoon and evening encouraging this development. This activity will likely spread towards Northwest OH and Lake Erie late Thursday afternoon or evening. It is somewhat uncertain if this activity can progress east-southeast across more of the area later Thursday evening as it begins outrunning the front, though the southern reaches of lift associated with the aforementioned shortwave and a modest but moist west-southwesterly low-level jet may allow activity to maintain across the area Thursday evening into Thursday night.

The front itself slowly crosses Lake Erie late Thursday night or early Friday, and then gradually sags across the area through Friday afternoon or early evening before clearing. There are some hints that convection may re-develop along the front over or near Lake Erie late Thursday night or early Friday morning. This is not as confident, but either way there will likely be a blossoming of showers and storms along and south of the front during the day Friday as we see heating of the moist pre-frontal airmass. Shower/storm chances will decrease from north to south Friday afternoon and evening as the front clears the area.

In terms of severe weather potential, it is overall on the lower side with this system. The SPC has included Northwest OH and Lake Erie in a Day 2 Marginal Risk (level 1 of 5) for isolated damaging wind gusts late Thursday. 20-25 knots of deep-layer shear and a strongly heated and mixed low-level airmass could support loose convective organization and cold pool development, which can support the marginal damaging wind risk. Otherwise, the environment features marginal and skinny instability profiles and overall limited wind shear, which argues against a more significant severe weather threat. The environment does become conducive to efficient rain rates with any convection late Thursday into Friday as precipitable water values climb to near 1.80", with warm mid-levels supporting skinnier instability profiles. A modest west-southwest low-level jet feeding into the sagging west-east oriented cold front could also support a little bit of training. While coverage and placement of convection becomes more uncertain Thursday night into Friday, will need to keep in mind the potential for an isolated heavy rain and flash flooding risk. The WPC does have a Marginal Risk for excessive rainfall/flash flooding Thursday into Friday.

KEY MESSAGE 3... The late week front may still be close enough by to maintain a low risk for showers or a storm in our far southern counties on Saturday. Otherwise, high pressure builds into the southern Great Lakes through the weekend, providing for a more prolonged period of tranquil conditions. Strong ridging is expected to build over the Plains late this weekend into early next week. Northwest flow aloft on the eastern side of this ridge will become established across the area, though dry conditions associated with continued surface high pressure should limit the potential for convection to spill in from the northwest through Monday and Tuesday. A warming trend is expected early next week as said ridge tries expanding to the east, but there is uncertainty over how quickly troughing over New England gets kicked out which will affect our temperatures.

AVIATION /06Z Wednesday THROUGH Sunday/

The main aviation weather concern for this 06z TAF update will be some patchy to areas of fog possible through sunrise across NEOH and NWPA. For FDY, TOL, ERI, and CLE, MVFR light fog 3sm to 5sm will be possible between 09z and 13z this morning. The better chance for MVFR fog will be at MFD, CAK, and YNG between 08z and 13z with also the potential for a brief period of IFR 2sm fog and broken ceilings around 700 feet. We have TEMPO groups mentioning this potential. After sunrise, the patchy fog and any low stratus ceilings will quickly lift out to VFR conditions with mostly clear skies after 14z this morning. VFR is expected for the rest of the TAF period later today into this evening. Winds will be light and variable through this morning before becoming northwesterly to northerly 5-10 knots through the rest of today. Light and variable winds return again this evening.

Outlook...Non-VFR possible with scattered thunderstorms Thursday afternoon through Saturday afternoon.

MARINE

Overall good marine conditions are expected today and tomorrow with winds around 10 knots or less and waves 1 foot. High pressure will keep the weather quiet over the eastern Great Lakes. A light land and lake breeze will be possible early this morning and later this afternoon. Southwesterly winds around 10 knots are expected Thursday ahead of an approaching cold front. The front will be with slow to pass through. Winds will eventually shift out of the north by late Friday. Next potential thunderstorms that could impact localized marine conditions is Thursday evening into Friday. High pressure will build back over Lake Erie this weekend with northeasterly flow 10 to 15 knots on Saturday and waves 1 to 3 feet. NW winds 5 to 10 knots expected Sunday and waves 1 to 2 feet. Marine headlines are not expected for Lake Erie through this weekend.

CLE WATCHES/WARNINGS/ADVISORIES

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