textproduct: Cleveland

WHAT HAS CHANGED

Added frost to the forecast for portions of the area on Thursday night and Friday night. Chances of rain have trended up for Friday, especially south of a line from Findlay to Youngstown.

KEY MESSAGES

1) Below normal temperatures are expected through the weekend with patchy frost on Thursday night and greater coverage of frost on Friday night.

2) Opportunities for showers will linger through the end of the week within this cooler pattern.

3) The weather pattern trends gradually warmer with the potential for thunderstorms next week.

DISCUSSION

KEY MESSAGE 1...

Low pressure is over western Pennsylvania and the associated cold front is south of the area this afternoon. Temperatures range from the upper 40s near the lakeshore to mid 50s inland. This will be the beginning of a cooler pattern as an upper level trough sets up over the Great Lakes Region through Saturday. Cold advection will continue overnight with 850mb temperatures falling to around -2C for Thursday and Friday before trending slightly cooler for Saturday. Normal highs at the end of April are in the mid 60s but we will tend to see high temperatures limited to the low to mid 50s for the next 3 days. Ample cloud cover tonight will keep temperatures near 40 degrees and do not expect to have any issues with frost. More breaks are expected in the cloud cover from Thursday night through Saturday night which will allow for colder overnight lows and potential for frost. For Thursday night the frost looks to primarily effect Northwest Pennsylvania while coverage of frost on Friday night looks to encompass most inland areas. A ridge of high pressure will build overhead Friday night with low temperatures generally in the low 30s but could drop below freezing for inland portions of Northwest Pennsylvania. Frost/Freeze headlines may be needed but will depend on the degree of clearing over the next few nights.

KEY MESSAGE 2...

Rain associated with the cold front is exiting the area to the east this afternoon while additional showers have developed upstream in northern Indiana and western lower Michigan along a trailing surface trough. These showers are expected to reach northwest Ohio this evening then decrease in coverage as the trough swings southeast across north central Ohio overnight. This axis of moisture will remain a focus for showers to develop on Thursday afternoon with steep low level lapse rates and a minimal amount of instability.

A shortwave trough will round the base of the upper level ridge Thursday night into Friday. Weak low pressure will slide from Illinois across Indiana and Ohio bringing a swath of rain Thursday night into Friday. Chances of rain have trended up with this system, with greatest potential focused along and south of Route 30.

KEY MESSAGE 3...

The persistent upper level trough finally shifts off the East Coast on Sunday night, and temperatures trend back towards normal on Monday. Showers and thunderstorms are possible both along a warm front and then ahead of a cold front later Monday as the next trough moves through the northwest flow aloft. Temperatures trend warmer again on Wednesday with showers and thunderstorms possible again.

AVIATION /18Z Wednesday THROUGH Monday/

Widespread MVFR and IFR conditions are seen across the region as a low pressure system moves off to the east. Rain showers are currently east of a line from KCLE to KMFD and will continue to move eastward through the afternoon into early evening. West of the showers, ceilings have climbed to around 1-1.5kft, and to the east in the showers terminals have ceilings less than 1kft. Visibility may drop down to less than 3SM at times in the heavier portions of showers. After the showers exit to the east early this evening, there will still be plenty of low-level moisture in the region that will keep ceilings down in IFR conditions with some pockets of MVFR possible. There will be a slow improvement in conditions late in the TAF period, though still expect non-VFR ceilings for most locations with KCLE improving after 18Z tomorrow.

Winds behind the low pressure system will be mainly out of the north to start then backing to be out of the northwest throughout the TAF period. Expect winds to be lighter overnight around 5 knots and increasing to around 10 knots by tomorrow afternoon.

Outlook...Non-VFR possible in showers and low ceilings late Thursday night into Friday morning.

MARINE

North to northwesterly flow expected through Saturday evening across Lake Erie. Winds will be generally 5-15 knots during that time with periods of lighter winds possible Friday morning. Waves will continue to be 1-3 feet across that lake as well. By Sunday, high pressure will build in south of the region and winds will be 10-15 knots and shift to be westerly then southwesterly by the evening into Monday.

CLE WATCHES/WARNINGS/ADVISORIES

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