textproduct: Cleveland

WHAT HAS CHANGED

Slightly lowered dew points across Northwest Ohio this afternoon. Also increased PoPs Tuesday afternoon into early Wednesday morning as persistent, widespread precipitation is expected.

KEY MESSAGES

1) Isolated to scattered showers and thunderstorms are possible this afternoon and evening along a surface trough. A few storms could become strong to severe across portions of North Central and Northwest Ohio.

2) Widespread showers and embedded thunderstorms will arrive across the region Tuesday into Wednesday. Some nuisance and/or minor river flooding is possible.

3) A chilly air mass will return across the region towards the end of the week with another round of Frost conditions possible.

DISCUSSION

KEY MESSAGE 1...

A weak mid-level shortwave will move northeast across the Ohio Valley ahead of a stronger upper-level trough near the Upper Great Lakes today. A narrow corridor of higher dew points in the 50s and mid-level lapse rates of near 7 C/km will accompany this feature, potentially yielding MLCAPE values in excess of 1000 J/kg by this afternoon and evening.

The latest SPC SWODY1 marginal risk encompassing portions of North-Central and Northwest Ohio appears reasonable at this time given the environment in place (modest westerly bulk shear of around 30 to 35 knots and a favorable DCAPE gradient in place), though recent guidance has continued to trend convective initiation further north and northwest. If these trends continue, much of the area may not see much precipitation until later tonight.as the cold front approaches. The main hazards with any stronger storms that form would be isolated damaging wind gusts and large hail.

KEY MESSAGE 2...

A secondary area of low pressure will develop along a slow- moving cold front as it approaches the Lower Great Lakes region on Tuesday. Widespread showers and embedded thunderstorms are expected with the front, especially late Tuesday into Wednesday, with high probabilities for much of the area to receive at least 1 inch of rainfall, with a narrow corridor up to 1.5 inches possible. Although not particularly impressive amounts, the recent wet pattern coupled with a widespread rain could lead to some nuisance road and/or minor river flooding and will be something to watch in future forecast iterations.

KEY MESSAGE 3...

Another anomalously-cold air mass will enter the region towards the end of the week, with 850 mb temperatures falling to near or just below -2C. Though not as cold as the previous cold air mass over the region, there does exist some potential for another round of Frost conditions, especially Thursday night into early Friday morning.

AVIATION /18Z Monday THROUGH Saturday/

VFR in mostly clear skies is expected through most of this afternoon before showers/storms develop across NW OH late this afternoon and expand east through tonight. Confidence in showers/storms are highest at NW OH and lakeshore terminals (including KTOL/KFDY/KCLE/KERI) this evening, although showers may move inland and possibly impact KMFD/KCAK/KYNG later tonight. There's some uncertainty in the placement/exact timing of storms tonight so amendments are likely as the forecast evolves. Multiple rounds of showers are possible overnight/early Tuesday morning before widespread rain fills in across the northwestern portion of the area and along the lakeshore towards the end of the TAF period. As far as flight conditions go, VFR is generally expected outside of rain with non-VFR possible in any showers/storms that move directly over terminals. Lower ceilings will likely arrive with increasing moisture and more widespread showers Tuesday morning/early afternoon, although it's possible that ceilings remain in the 3000-5000 ft range until the more widespread precip develops Tuesday afternoon.

Winds will be breezy and out of the southwest through this evening. Sustained winds of 15 to 20 knots and gusts to around 30 knots are likely at KTOL/KFDY through this evening with winds to 12 to 15 knots and gusts to 25 knots expected elsewhere. Winds will diminish slightly in NW OH by early Tuesday morning. Winds may become erratic and gusty in any thunderstorms that move directly over terminals this evening/tonight. A 40-50 knot LLJ will likely result in LLWS at most terminals tonight into early Tuesday. Winds will begin to shift to the northwest from west to east towards the end of the TAF period.

Outlook...Periodic rain showers and thunderstorms with non-VFR conditions are expected through Wednesday morning. Showers may return again Thursday night through Saturday.

MARINE

Southwest winds of 10-20 knots will continue today on the western half of Lake Erie with 10-15 knots on the east half of the lake. Winds will increase slightly to 15-20 knots across most of the lake tonight ahead of a cold front. The front will sink south across the lake on Tuesday afternoon with winds decreasing behind the front. Northerly winds of 5-15 knots will persist through Thursday before backing to southwesterly again on Friday.

CLE WATCHES/WARNINGS/ADVISORIES

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