textproduct: Cleveland

WHAT HAS CHANGED

Storm total rainfall amounts continue to trend down across portions of Central Ohio. The risk of excessive rainfall has been lowered to Marginal (1 out of 5).

KEY MESSAGES

1) A soaking rain with scattered thunderstorms is expected tonight into Monday. Rainfall amounts of 0.75-1.25 inches are expected with locally higher amounts possible.

2) Temperatures will be slightly below normal through Friday then trend warmer over the weekend.

DISCUSSION

KEY MESSAGE 1...

High pressure over the local area this morning will shift east into New England tonight. Meanwhile surface low pressure ahead of a fast moving shortwave trough will approach from the west overnight. There will be considerable dry air to overcome in the low and mid-levels with isentropic ascent increasing from west to east this evening. Precipitation trends over the last 48 hours are favoring the heaviest rain of an inch or more across northern portions of the forecast area. Robust convection is expected to develop this afternoon in the warm sector across Illinois and Indiana, with storm motion to the southeast heading into tonight. This is expected to result in lower precipitation amounts across central Ohio than previously thought over the last couple days. Forecast amounts in the southern counties look closer to a half to three quarters of an inch now as some of the moisture transport into the region is cut- off.

Elevated convection remains possible late Sunday night into Monday morning and we will monitor rainfall rates in this moist environment. The overall concern for heavy rainfall and flooding with this system has trended down though. The rain looks most persistent across the north late Sunday night before a mid-level dry slot arrives on Monday morning. Despite the drying aloft, scattered to numerous showers are expected to fill back in on Monday afternoon as the cold front wraps in from the northwest. CAPE of 500-700 J/kg is expected in our southeastern counties so thunderstorm activity may increase along the front during the afternoon.

In addition to the rain, gusty northeast winds will be focused downwind of Lake Erie on the western and central basin. Gust near the lakeshore will be 30-35 mph at times. Temperatures will be impacted by the cooler and damp conditions with highs only reaching the low 70s on Monday.

KEY MESSAGE 2...

The overall longwave pattern shows a quasi-zonal flow with troughs moving southeast through the Great Lakes Region through Friday. This pattern will keep temperatures on the cool side of normal for most of the week with scattered showers and thunderstorms possible Thursday afternoon and evening. Models all depict the ridge starting to amplify aloft for next weekend with temperatures trending warmer.

AVIATION /12Z Sunday THROUGH Thursday/

VFR continues this morning, but mid-level clouds will gradually increase from southwest to northeast this afternoon and evening ahead of a warm front as low pressure moves out of the Mid Mississippi Valley. This will lower cigs and cause them to become broken to overcast at 5 to 7 thousand feet by tonight. Rain will eventually overspread all terminals from west to east tonight, with conditions gradually falling to MVFR and IFR. Went conservative on visibilities at this point because most of the rain will be light tonight, but could see IFR vis in pockets of heavier rain

Light W to NW winds this morning will turn N to NW at 5-10 knots this afternoon then E at 5-10 knots tonight.

Outlook...Non-VFR likely Monday with rain showers. Non-VFR possible again in rain showers Wednesday through Thursday.

MARINE

Light N to NW winds are expected early this morning increasing to 5-10 knots this afternoon as high pressure gradually slides into the eastern Great Lakes to allow low pressure to approach from the Mid Mississippi Valley tonight. Winds will turn E this evening ahead of the warm front extending east from this low, and the E winds are expected to become quite strong in the 15-25 knots range late tonight and early Monday, especially in the western and central basins. This will build wave heights to 3-5 feet. As the low passes across northern Ohio Monday, winds will quickly turn NE behind the trailing cold front, staying in the 15-20 knot range. Small Craft Advisories and Beach Hazards Statements will be needed late tonight and Monday for at least the western and central basins for winds, waves, and rip currents. Light winds are expected Tuesday through Wednesday as high pressure builds down across the Great Lakes before turning S to SW ahead of the next low and associated cold front Thursday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement from late tonight through Monday afternoon for OHZ003-007-009. Beach Hazards Statement from Monday morning through Monday afternoon for OHZ010>012. PA...None. MARINE...Small Craft Advisory from 4 AM to 5 PM EDT Monday for LEZ142>144. Small Craft Advisory from 8 AM to 5 PM EDT Monday for LEZ145>147.