textproduct: Cleveland

WHAT HAS CHANGED

Slight Risk (Level 2 of 5) for severe weather remains for today with damaging winds as the primary threat and a secondary threat of quick spin-up tornadoes. Additionally, a heavy rain and flooding threat is possible across the majority of the region as additional rainfall is likely.

KEY MESSAGES

1) There will be another chance for strong to severe thunderstorms this evening into the early overnight hours. Minor flooding is also possible with heavy rainfall rates.

2) There will be a pattern shift starting Sunday through the middle of the with much cooler temperatures across the region with a few periods of precipitation possible.

DISCUSSION

KEY MESSAGE #1: The frontal boundary that brought showers and thunderstorms to the region on Friday will continue to lift north through this morning as a warm front. This will put the majority of the region within the warm sector of a parent low pressure system that will be entering the Great Lakes region from the west. Temperatures throughout the day will climb into the mid to upper 70s with some areas in eastern Ohio touching the low 80s. Dew points will also be on the rise up into the 60s with sufficient southwesterly flow across the region. As a result, there will be plenty of instability with MLCAPE values around 1000-1500 J/kg and 0-3km lapse rates around 7.0 C/km. Though, despite these factors, there will be minimal forcing during the afternoon, so expecting only a few thunderstorms ahead of the front and forcing that will come with it. As the front approaches, low level winds will begin to strengthen with a low level jet of around 40-50 kts and 0-1km shear around 15-20 kts. LCL levels will also be less than 1km which will support the chance for a few tornadoes to quickly spin up with the front. With all of this, the Storm Prediction Center has continued the Slight Risk (Level 2 of 5) for severe weather driven mainly by the damaging wind potential and a secondary threat of tornadoes. The window for severe weather and frontal passage will begin in the western counties around 4-5PM and move through region exiting to the east around midnight.

Along with the severe weather threat, heavy rain and flooding will also be possible with the showers and thunderstorms. Precipitable water values will be around 1.25" and sounding climatology for ILN and PIT have these values upwards of the 90% percentile. QPF for the day will be around 0.50-0.75" on top of the rainfall that has fallen last night and earlier this week. Locally higher amounts are possible within thunderstorms with higher rainfall rates. Additional rises on area rivers and streams are likely tomorrow evening.

KEY MESSAGE #2: As the cold front from Saturday evening exits to the east, the surface low will move northeastward into eastern Canada and a much cooler air mass will move in behind. The upper level trough will be slow to exit and stay situated across eastern Canada down into northeastern CONUS. This will keep temperatures cool with persistent northwesterly flow through Tuesday night. Highs on Sunday through Tuesday will be in the upper 30s to mid 40s with overnight lows down into the mid 20s to low 30s. Generally, dry weather is expected across much of the region, though a shortwave feature will move in from the northwest on Monday through Tuesday that will bring precipitation chances for mainly north central and eastern Ohio and northwestern Pennsylvania. Precipitation will stay mainly as rain on Monday and will transition to a wintry mix and wet snow as a cold front passes through Monday night. Snow showers are likely to continue across northeastern Ohio and northwestern Pennsylvania into Tuesday as ridging will build in and moisture diminishes. The upper level trough moves out to the east as well and low to mid level flow shifts to be out of the southwest and temperatures will begin to warm. To end the week, high temperatures will begin to warm to be above average.

AVIATION /12Z Saturday THROUGH Wednesday/

Most terminals have VFR conditions this morning except in NW Ohio where skies were relatively clear, allowing for the formation of low stratus to develop. This should be short lived at FDY while IFR/MVFR will be more prone to hang on at TOL. A warm front will lift north this morning, with VFR conditions into this afternoon. A band of showers and thunderstorms is forecast to sweep west to east across the area today ahead of a cold front. Have timed that into the terminals between as early as 19Z in Northwest Ohio, reaching Cleveland between 22-24Z and ERI between 00-02Z with rain to follow for a couple hour. Some thunderstorms this afternoon will have the potential to be strong with pockets of winds as high as 40-50 knots and MVFR conditions. Ceilings of 2500-3500 feet will persist behind the cold front.

Winds today will veer to the south this morning with gusts to 25 knots. Winds will eventually shift to the west with the passage of the cold front tonight.

Outlook...Non-VFR with low ceilings may linger through Sunday. Non- VFR may return Monday and Monday night in rain and/or snow showers.

MARINE

Winds across Lake Erie are currently 10-15 knots out of the east to northeast and will shift to be out of the south by this afternoon with the western basin increasing to around 15-20 knots. A strong cold front will move across the region this evening quickly shifting winds to out of the west by late tonight. Stronger winds may be possible within showers and thunderstorms as the cold front moves through Winds will stay elevated through Sunday with sustained winds of 15-20 knots and waves increasing to 3-5 feet. A Small Craft Advisory will be needed for early Sunday morning through Monday morning when winds and waves begin to subside. Winds will increase again Tuesday with a cold front passing through the region and will likely warrant another Small Craft Advisory. High pressure will begin to build into the region on Wednesday and quieter marine conditions are expected.

CLE WATCHES/WARNINGS/ADVISORIES

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