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 /12Z Monday THROUGH Friday/

Clear skies this morning will give way to gradually increasing sct-bkn VFR clouds through the afternoon with scattered showers and thunderstorms developing generally after 20Z. A capping inversion is likely until we moisten sufficiently aloft with the arrival of shortwave energy towards late afternoon to kick off activity. High resolution models depict scattered showers across northeast Ohio along a warm front, with better support for thunderstorms moving into Northwest Ohio and expanding east across Lake Erie towards CLE/ERI through the evening. We have a TEMPO for thunderstorms in TOL where confidence is highest in thunderstorms this evening. Elsewhere, covered the potential for showers with VCTS or -shra. The moisture axis ahead of the approaching trough sinks south into the area overnight and bring additional showers back into favored terminals late in the period.

Breezy southwesterly winds are expected today after 15Z with gusts of 22-28 knots. Where wind gusts drop off tonight the concern for low level wind sheer will return with speeds of 40-50 knots at 2K feet.

Outlook...Periodic rain showers with non-VFR are expected Monday night through Wednesday morning with occasional thunderstorms. Showers return again Thursday night into Friday with the next front.

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.