textproduct: Cleveland

WHAT HAS CHANGED

The Slight Risk for Tuesday has been expanded to include nearly the entire forecast area. Otherwise, no significant changes were made with this forecast package.

KEY MESSAGES

1) The hottest temperatures of the year thus far will continue through Tuesday. The heat will break behind a cold front on Wednesday with below normal temperatures continuing into Thursday.

2) A few strong to severe thunderstorms are possible in Northwest Ohio and possibly close to the lakeshore this afternoon into early this evening. Another round of strong to severe storms is possible on Tuesday afternoon and evening.

3) Unsettled weather with periods of rain expected and thunderstorms possible over the holiday weekend.

DISCUSSION

KEY MESSAGE 1... Deep warm air advection will remain in place across the area over the next couple of days, resulting in above normal to near record temperatures across the area through Tuesday. Temperatures will remain in the 80s to around 90 degrees through the remainder of this afternoon with temps into the upper 60s and lower 70s tonight. Temperatures will decrease a bit faster in locations that receive rain (most likely NW OH) this afternoon. Temperatures will once again rise into the 80s and possibly touch 90 degrees Tuesday afternoon, although confidence in temps reaching the upper 80s and lower 90s (and possibly touching record values) is slightly lower than today due to low- end chances of morning showers, afternoon convection, and increased cloud cover. Dew points will likely be a bit higher on Tuesday afternoon so it will definitely feel muggy. Those spending time outside this afternoon and during the day Tuesday should wear light/loose-fitting clothing and hydrate and sensitive groups should consider limiting time outdoors during peak heating.

Temperatures will cool down for mid to late week with highs in the 60s expected Wednesday and Thursday.

KEY MESSAGE 2... As of 230 PM EDT, a line of severe thunderstorms was moving east across Indiana. There is a very tight instability gradient that ends just within the western fringe of the local area so anticipate storms to quickly weaken as they encounter less instability later this afternoon and early this evening. Nonetheless, isolated to scattered strong to severe storms are possible, especially in the Slight Risk (level 2 of 5) area that's in place across the Toledo area as the storms move in over the next couple of hours. Isolated stronger storms are possible in the northern portion of the area where there is a Marginal Risk (level 1 of 5) of severe weather. Damaging wind gusts will be the main threat, however large hail is possible and a quick spin-up can't be ruled out in the Slight Risk area.

Once convection weakens this evening, scattered showers may persist across NW OH through the overnight hours with low-end PoPs expanding east across the local area Tuesday morning. The moist, unstable air mass will remain in place over the area on Tuesday, especially if the forecast trends drier and sunnier than currently forecast. MLCAPE values will likely exceed 2000 J/kg by peak heating Tuesday with effective bulk shear values likely increasing to 30+ knots as a cold front advances east towards the area Tuesday afternoon. Scattered showers and thunderstorms are likely Tuesday afternoon into Tuesday evening, although there's some uncertainty in the placement of convective initiation and exact timing of thunderstorms. Thunderstorm development will likely rely on early day cloud cover and any showers that develop Tuesday morning. Given the instability and shear profile, storms may be strong to severe and there is a Slight Risk (level 2 of 5) of severe weather across nearly the entire area. Damaging wind gusts will be the primary concern, but some storms may produce large hail. A few tornadoes cannot be ruled out.

KEY MESSAGE 3... A period of dry weather is expected Wednesday through Thursday before precipitation chances increase Friday through the holiday weekend as weak low pressure and a frontal boundary slowly drift north across the Ohio Valley. There's still quite a bit of uncertainty in the timing and coverage of showers (and possibly a few thunderstorms) over Memorial Day Weekend, but at the moment it looks like the best chances of precipitation will occur Friday night and Sunday into Monday. Confidence in the likelihood of hazardous weather is low this far out, but will continue to monitor trends in guidance and adjust the forecast/key messages as necessary.

AVIATION /00Z Tuesday THROUGH Saturday/

Thunderstorms have began to diminish across NW OH over the past couple of hours. A weakening line of showers are pushing eastward now and has occasionally brought visibility down to MVFR conditions, though expect conditions to be primarily VFR even in rain showers. Showers will taper off over the next couple of hours with no impacts expected east of KCLE. Overnight, a LLJ will set up over western OH creating LLWS conditions for a few hours as surface winds become around 10 knots. Winds will begin gusting to 25-30 knots out of the southwest starting around 12-13Z tomorrow morning and persist through much of the day. Another round of showers and thunderstorms are expected at the end of the TAF period, after 22Z, with only KTOL, KFDY, and KCLE included with this issuance.

Outlook...Non-VFR likely at times in showers/thunderstorms late Tuesday into Wednesday. Non-VFR possible in showers on Friday into Saturday.

MARINE

Southwest/offshore winds 15-25kts through Tuesday and wave heights increasing rapidly away from shore with 1-3ft in the nearshore zones and 2-4ft in the open water zones. A cold front comes through Tuesday night with northerly winds 10-15kts through Wednesday, increasing to 15-20kts out of the northeast Thursday and 2-4ft waves for the central and western basins. Winds become light and variable into the weekend.

CLIMATE

High temperatures today and Tuesday will approach record values. The following are the records for May 18 and 19 at local climate sites.

Date Toledo Mansfield Cleveland Akron Youngstown Erie 05-18 95(1962) 92(1962) 91(1962) 92(1962) 92(1962) 89(1889) 05-19 92(1996) 88(1964) 88(1998) 91(1911) 89(1934) 90(1996)

CLE WATCHES/WARNINGS/ADVISORIES

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