textproduct: Cleveland

WHAT HAS CHANGED

Models have trended a bit slower regarding the onset of precipitation on Friday, pushing it into the late afternoon into the evening across southern counties. Still expecting widespread showers to push north late Friday.

KEY MESSAGES

1) Multiple rounds of showers and thunderstorms are expected to impact the area through the holiday weekend, bringing locally heavy rainfall and potential flooding concerns.

2) High pressure midweek will allow for warmer temperatures to move back into the area.

DISCUSSION

KEY MESSAGE 1... As high pressure slowly drifts to the northeast on Friday, a weak surface low will begin to move north from the Gulf Coast area towards the region. As a warm front approaches from the south Friday evening, overriding moisture supported by an upper level shortwave will result in widespread showers spreading north ahead of the boundary. The overriding has slowed a bit, pushing the bulk of precipitation to begin late afternoon into the evening and have opted to reflect this trend in the forecast. By Friday evening, much of the area should be experiencing rainfall. The biggest uncertainty will be the thunder potential, but given some modeled elevated instability, cannot rule out a few rumbles, however nothing severe is expected at this time. Late Saturday, the warm front will finally push north of the area, allowing for a break in showers to spread west to east Saturday night. On Sunday, much of the area should reside in the warm sector of the low for much of the day, allowing for increased instability across the area. This along with a prefrontal trough may allow for some diurnal thunderstorms to develop ahead of the approaching cold front. The cold front will be relatively weak as it pushes east late Sunday into Monday. On Monday, showers should gradually diminish across the area, leaving much of the Memorial Day holiday dry. Temperatures will gradually warm through the weekend with highs on Friday in the 60s, gradually increasing into the 70s by Monday.

The primary concern going into the holiday weekend is how much rainfall will occur across the area with the return of a moist airmass with PWAT values climbing over 1.5". Rainfall totals have not changed much from previous forecasts with totals across the area in the 1-1.5" range over a 24 hour period. The bulk of this water will be handled well, however some area rivers may rise into flood and typical flood prone locations may see problems. Given the time span, flash flood concerns remain minimal with a higher risk of gradually water rises. To highlight this heavy rain and flood concern, WPC has kept the Ohio counties in a Day 2 Marginal (level 1 of 5) ERO.

KEY MESSAGE 2... After this low pressure system moves north out of the area, a surface ridge centered over the Southeastern U.S. will begin to nudge north, allowing for a more summer-like airmass to return. An associated high at the surface should keep precipitation chances at a minimum through midweek with highs gradually climbing towards the 80s. Given the source of the airmass, humidity values are also expected to climb with peak RH values likely exceeding 50%. These humid conditions have the potential to increase apparent temperatures into the 80s. Confidence is fairly low in the exact details given how far out that is. This warmth looks likely to stick around as the latest CPC 6-10 Day outlook suggests above average temperatures will impact much of the northern U.S.

AVIATION /18Z Thursday THROUGH Tuesday/

VFR conditions are anticipated through at least early Friday morning before clouds increase from the south late in the TAF period. A few showers and MVFR ceilings can't be ruled out at southern terminals towards the end of the TAF period, however it appears that the chance is greater after 18Z Friday.

Winds will be out of the east/northeast at 8 to 15 knots throughout the TAF period with gusts to 20 to 25 knots during the day today and Friday. Winds will be slightly higher at KERI this afternoon with sustained winds to 20 knots and gusts to 30 knots expected. Gusts should diminish after sunset.

Outlook...Non-VFR expected at times in rain late Friday through Saturday night. Scattered showers and thunderstorms with non- VFR conditions possible again on Sunday and Monday.

MARINE

Unsettled marine conditions will persist through late Saturday and Small Craft Advisories and Beach Hazards Statements remain in place for the next couple of days with headlines ending from the east starting Friday evening. East/northeast winds to 15 to 25 knots are expected through Friday evening with winds becoming more southeasterly on Friday night. Waves will be highest at 5 to 7 feet in the central basin during this time, including the eastern side of the Islands.

Winds will likely diminish a bit during the day Saturday as low pressure lifts northeast towards Lake Erie, although offshore winds around 20 knots are likely in the eastern basin through Saturday. Headlines may need to continue if winds trend higher. Winds become more light and variable Sunday through Tuesday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement through Saturday morning for OHZ003- 007-009-010. Beach Hazards Statement through Friday evening for OHZ011-012- 089. PA...Beach Hazards Statement through Friday evening for PAZ001. MARINE...Small Craft Advisory until 10 AM EDT Saturday for LEZ142>145. Small Craft Advisory until 10 PM EDT Friday for LEZ146>149.