textproduct: Cleveland

WHAT HAS CHANGED

Our total rainfall forecast for later today into Saturday has trended lower in our region based on the latest expected evolution of the weather pattern at the surface and aloft. We now expect about 0.25" or less north of roughly U.S. Route 30 and approximately 0.25" to 0.60" elsewhere.

KEY MESSAGES

1.) Periodic rain showers are expected and isolated thunderstorms are possible later today into Saturday.

2.) Warmer and more humid weather is expected this Sunday through Thursday. Periodic showers and thunderstorms are possible during most of the same time period.

DISCUSSION

KEY MESSAGE 1... W'erly flow aloft and embedded shortwave disturbances affect our region through Saturday. By Saturday night, a high pressure ridge aloft should begin to build from the Upper Midwest and vicinity. At the surface, a cold front appeared to extend SW'ward across central Lake Erie, just west of Cleveland, just west of Mansfield, and just east of Marion as of 2 AM EDT this morning. This front will continue moving SE'ward, exit the rest of our CWA by daybreak this morning, and should settle in vicinity of the Middle and Upper OH Valley by midday today through Saturday night. Behind the front, a high pressure ridge builds slowly from the western Great Lakes and vicinity through Saturday night. Weak surface lows accompanying the shortwave disturbances aloft are expected to move along the front this afternoon through sunset Saturday night. Odds favor dry weather in our CWA this morning courtesy of boundary layer stabilization via nocturnal cooling ahead of the cold front and stabilizing subsidence accompanying the aforementioned surface ridge. Cloud breaks, lingering low-level moisture from recent rainfall, and weak or calm surface winds should permit patchy radiation mist or fog development through daybreak this morning. By mid-morning, any mist or fog is expected to dissipate via diurnal convective mixing of the boundary layer.

During this afternoon through tonight, periods of rain, steady to heavy at times, should overspread our region from the south and west courtesy of moist isentropic ascent associated with the warm conveyor belt of a primary low-level low along the aforementioned front. Isolated thunderstorms are possible, especially this afternoon and evening, since the isentropic ascent may release weak, yet sufficient and primarily elevated CAPE. During the daylight hours of Saturday, lingering and periodic showers and isolated thunderstorms are expected to end generally from WNW to ESE as the warm conveyor belt exits generally E'ward and the ridge at the surface and aloft continues to build from the west. Widespread dry weather is then expected through Saturday night amidst stabilizing subsidence accompanying the ridge. The greatest rainfall in our CWA is expected roughly along and south of U.S. Route 30. This is where periods of rain should be more-persistent since that portion of our CWA will be located closer to the surface front, frontal surface lows, and associated stronger synoptic-scale forcing for ascent.

Weak low-level CAA behind the aforementioned cold front and abundant cloud cover should contribute to below-normal highs in the 70's late this afternoon. Greater sunshine and daytime heating should permit slightly warmer highs in the 70's to 80F late Saturday afternoon. Overnight lows should reach mainly the upper 50's to lower 60's around daybreak Saturday and Sunday, respectively.

KEY MESSAGE 2... A warming trend and increase in humidity are expected this Sunday through Thursday as the mid/upper-level ridge axis shifts from near the MS Valley to near the eastern Great Lakes and the Atlantic coast of the FL peninsula, which will cause our region to become located within a synoptic-scale low-level warm/moist air advection regime from the Gulf as we become located along the western flank of the surface portion of the ridge. Daytime highs should moderate from the 80's to lower 90's on Monday to mainly the upper 80's to mid 90's on Thursday. Daily maximum heat indices may reach the 100F to 105F range in portions of our CWA on Tuesday through Thursday. Stay tuned to forecast updates and possible hot weather alerts. Overnight lows should moderate from mainly the upper 50's to upper 60's around daybreak on Monday to the 70's around daybreak on Thursday.

Current odds favor dry weather through Tuesday as relatively- strong and stabilizing subsidence associated with the ridge continues to impact our region. Occasional showers and thunderstorms are possible this Tuesday night through Thursday as subtle shortwave disturbances ripple generally eastward through the ridge aloft, are accompanied by surface trough axes, and low-level convergence/moist ascent along the surface trough axes release at least weak to moderate instability. Some storms may be strong to severe as the aforementioned shortwave disturbances interact with the ridge aloft and tighten the isobaric height gradient aloft, which in turn should yield at least moderate deep-layer bulk shear.

AVIATION /12Z Friday THROUGH Tuesday/

Some mist/fog has developed across the area this morning and should be quick to mix out with daytime heating. Meanwhile, some MVFR ceilings is pushing southeast across Lake Erie and will impact KERI for the first half of the morning. A trough will start to enter the Ohio and Tennessee River Valleys tonight and some mid-level clouds will enter this afternoon ahead of this system. Rain will begin moving in this evening and into the overnight bringing a gradual decline into MVFR with light rain showers. This rain should persist through the overnight and reach most of the terminals. Winds will be light to start and generally westerly. Winds will start to shift to the east later today and be the main wind direction for the end of the TAF period.

Outlook...Non-VFR continuing with rain showers on Saturday. Non-VFR possible in fog/mist Sunday morning.

MARINE

With a low pressure system and associated cold front departing to the east, high pressure will briefly build from the north today. This will allow for light and variable winds over the lake for the first half of the day before shifting around to the east. A weak low pressure system over the central United States will enter the Ohio and Tennessee Valleys tonight into Saturday. East to northeast winds will pick up into the 10 to 15 kt range as this feature moves to the south. High pressure will return for Saturday night into Sunday and sustain the east to northeast flow on the lake. High pressure will move east on Monday and allow for winds to shift to the southeast. A low pressure system over the northern United States will lift a warm front over the lake on Monday night into Tuesday and south to southwest flow will be favored. Overall, marine headlines are not expected at this time.

CLE WATCHES/WARNINGS/ADVISORIES

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