textproduct: Cleveland

WHAT HAS CHANGED

The forecast remains valid, overall, compared to the previous full update early this morning.

KEY MESSAGES

1.) Slightly below-average to near-average temperatures and periodic showers and thunderstorms are expected through Memorial Day. Enough rain should fall to cause minor flooding along some creeks and rivers in our area.

2.) Primarily dry weather and near-average to above-average temperatures are expected this Monday night through Friday, May 29th.

DISCUSSION

KEY MESSAGE 1... SW'erly to W'erly flow aloft and embedded shortwave troughs affect our region through Memorial Day. At the surface, a primary low should wobble NE'ward from northeastern AR late this afternoon to near central IN by daybreak Saturday before wobbling farther NE'ward to near central Lake Huron by daybreak Sunday. The low should then wobble E'ward to near the Gulf of Maine by Memorial Day. This low track should allow a surface warm front to drift NE'ward through our region during the daylight hours of Saturday through Saturday night, while a weak cold front should sweep generally SE'ward through our region late Saturday afternoon through Sunday night. Behind the cold front, a weak surface ridge should build from the northern and central Great Lakes through Memorial Day.

Periods of rain, steady to heavy at times, continue to overspread our region slowly and generally from the south the rest of this afternoon through tonight as isentropic ascent occurs along the upper-reaches of the warm front and taps into rich low-level moisture originating over the southern Gulf Stream and Gulf. Occasional and isolated thunderstorms are possible as the isentropic ascent releases weak instability. On Saturday through Sunday night, additional periods of rain, steady to heavy at times, are expected due to the following: moist isentropic ascent along the upper-reaches of the warm front and ahead of shortwave trough axes aloft; low-level convergence/moist ascent along the surface warm and cold fronts. These lifting mechanisms may release weak, yet sufficient instability to trigger additional isolated thunderstorms. Widespread rainfall totals of 1 to 2 inches are expected today through Sunday night. As rainwater runoff enters area creeks and rivers, some waterways (e.g. Killbuck Creek in Holmes County) should rise to minor flood stage this weekend. Minor flooding is possible in poor drainage and/or low-lying areas as well. Forecast confidence regarding widespread minor flooding remains low, which has precluded the issuance of a Flood Watch for any part of our CWA. On Memorial Day, current odds favor dry weather as stabilizing subsidence accompanies the aforementioned surface ridge. However, isolated showers and thunderstorms associated with the upper-reaches of the departing cold front may impact roughly the southeastern-third of our CWA.

Overnight lows should reach the upper 40's to lower 50's in NW PA and the 50's in northern OH around daybreak Saturday as abundant cloud cover associated with the aforementioned low pressure system and net low-level WAA ahead of the surface warm front contribute to limited nocturnal cooling. Given the projected evolution of the surface warm and cold fronts, daytime highs on Saturday should reach only the mid 50's to mid 60's in NW PA and the 60's to lower 70's in northern OH. Overnight lows should then reach the upper 40's to upper 50's around daybreak Sunday. On Sunday, peeks of sunshine and some daytime heating should allow daytime highs to reach mainly the upper 60's to upper 70's. Weak and net low-level CAA behind the cold front should be accompanied by lows reaching mainly the 50's around daybreak Monday. On Memorial Day, the aforementioned building surface ridge will be accompanied by stabilizing subsidence and clearing sky. Despite the expectation for our area to be located in the cool sector, sufficient sunshine and daytime heating should allow highs to reach the mid 60's to upper 70's. Note: the coolest highs on Sunday and Monday are expected over and within several miles of ~57F Lake Erie due to lake breeze development during the late morning through early evening hours of both days.

KEY MESSAGE 2... Current odds favor drier and warmer weather this upcoming Monday night through Friday since our region should become located downstream of a pseudo Rex Block aloft that should become focused over the central United States and vicinity. As a result, the aforementioned surface ridge should continue to affect our region and be accompanied by stabilizing subsidence that strengthens with time, promoting clearer sky and greater daytime heating. Daily lows should reach mainly the 50's or 60's around daybreak on Tuesday through Friday, while daily afternoon highs should reach mainly the 70's or 80's.

AVIATION /18Z Friday THROUGH Wednesday/

Expect deteriorating flight conditions over the next few hours down into the IFR range as a shield of rain spreads northward due to an area of low pressure moving into the region. The bulk of the forecast is for both ceiling and visibility IFR in prolonged, or at least periodic rain for the area. Winds become southeast over the forecast period gusting 20-30kts. These winds should keep ceilings from reaching LIFR as the lowest levels of the atmosphere remain stirred up.

Outlook...Non-VFR expected into late Saturday evening, and then again late Sunday into early Monday.

MARINE

Small Craft Advisory continues for the lake through late evening, and then for the western basin through Saturday morning as easterly winds 20-30kts persist with wave heights generally 3-5ft. Winds continue out of the southeast Saturday at 20-25kts, and wave heights 1-2ft in the nearshore zones, and 2-5ft in the open waters away from shore. Low pressure moves through, quickly followed by high pressure, and winds become light and variable for Sunday through Tuesday with wave heights less than a foot.

CLE WATCHES/WARNINGS/ADVISORIES

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