textproduct: Cleveland

WHAT HAS CHANGED

The Heat Advisory was cancelled early and the severe weather threat is over for this evening. Can't rule out a few more isolated to scattered thunderstorms but it's very unlikely that they pose a severe weather threat as instability has substantially decreased.

KEY MESSAGES

1) Periodic showers and thunderstorms will continue through Monday, especially in the afternoon and evening hours. Heavy rain and isolated flash flooding is possible.

2) Temperatures will return back to near normal Sunday through Tuesday, before becoming slightly above normal towards mid to late week.

DISCUSSION

KEY MESSAGE 1... The story over the next several days will be the potential for mainly afternoon and evening showers and thunderstorms across the region as a weak low pressure system gradually moves east from the Midwest into the Ohio Valley through Monday. The main concern with any showers and thunderstorms will be the heavy rain threat, given a lack of steering flow less than 15 knots, skinny CAPE profiles, and anomalously-high PWATs around 1.80 inches. Some isolated flash flooding (mainly rate-driven up to 2" per hour) is possible where storms persist, though given the continued chances into Monday, will also need to monitor area rivers for some minor rises. At this time, the overall severe weather threat remains low Sunday into Monday given the lack of flow, though can't rule out some isolated instances of wet downbursts in the strongest cells.

KEY MESSAGE 2... Anticipate a slight improvement in the overall weather pattern over the next week as temperatures moderate back to around normal (low to mid-80s), though maximum heat indices will remain elevated in the upper 80s to lower 90s. Temperatures may rise slightly above normal by mid to late week in the upper 80s to near 90, though heat indices should remain below 100.

AVIATION /00Z Sunday THROUGH Thursday/

VFR is mainly expected this evening and tonight, outside any additional isolated to scattered showers and/or thunderstorms (very low coverage/predictability). Patchy fog is possible tonight in central and east-central Ohio where afternoon storms occurred.

A low pressure system and cold front will start to move into the region Sunday and bring periodic rain showers with embedded isolated to scattered thunderstorms to the region. There could be some heavier rain that could bring non- VFR visibility and ceilings throughout the day on Sunday but it's difficult to target any specific periods at this time. For now, kept showers and VFR conditions throughout the day but when confidence increases, can introduce not-VFR and perhaps some TSRA. Afternoon convection will yield slightly higher confidence in thunderstorms for our southern TAF sites (KMFD, KCAK, and KYNG).

Winds will be light and variable overnight into Sunday with the low moving through the region but should eventually settle on northeast flow for Sunday.

Outlook...Non-VFR with occasional showers and thunderstorms possible through Tuesday afternoon. Scattered thunderstorms are also possible Thursday afternoon.

MARINE

North to northwest flow will continue over the lake this afternoon into this evening behind a lake breeze. A low pressure system will enter for Sunday and northeast flow will develop over the lake and strengthen to 15 kts and waves will build to 2 to 3 ft over the western and central basins. This unfavorable flow will continue into Monday and weaken on Tuesday with winds of 10 kts or less. High pressure will build from the west for Wednesday and Thursday and switch winds back to southerly, offshore flow. There is potential for a Small Craft Advisory with the northeast flow for Sunday and Monday if winds can increase just a touch from the current forecast.

CLE WATCHES/WARNINGS/ADVISORIES

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