textproduct: Cleveland

WHAT HAS CHANGED

No significant changes to the forecast. There is still potential for strong to severe thunderstorms today and especially Monday, but confidence in timing and placement of storms remains low.

KEY MESSAGES

1) Numerous rounds of showers and thunderstorms remain possible today through Wednesday. Storms may reach strong to severe limits, particularly later today through Monday night.

DISCUSSION

KEY MESSAGE 1... Broad upper level ridge sprawled across the western and central CONUS with deep troughing over the Great Lakes and eastern CONUS will usher in a period of active weather through mid-week. Northwest flow will allow for a series of "ridge riders", shortwaves aloft cresting over the ridge, to dive southeast into the region. There will be numerous chances for showers and thunderstorms, some strong to severe, beginning later today and continuing through Wednesday. There remains a fair amount of uncertainty with the timing and coverage of thunderstorms given a wide range of model solutions.

For today, some diurnal showers and thunderstorms may develop south of the Lake Erie lakeshore this afternoon and evening. There may be an isolated severe weather threat if we are able to destabilize enough given robust deep layer shear of 30-40 knots. During the late evening and overnight hours we will be monitoring the progression of an MCS diving southeast across Wisconsin and Lower Michigan towards the Lower Great Lakes region. This MCS will be following an instability gradient and may just clip our local forecast area to the west. Future shifts will need to monitor the latest hi-res guidance and upstream observations with forecast updates likely needed for this timeframe. Overall confidence in severe weather today through overnight remains low. The SPC has maintained a Marginal Risk (Level 1 of 5) for severe weather today and tonight.

Confidence in strong to severe storms increases on Monday as a surface low and cold front enter the region and provide additional upper level support. Much of the forecast for Monday will heavily depend on the outcome of the MCS tracking in the vicinity of the region Sunday night into Monday morning. Upstream storm development looks most probable along the aforementioned cold front across Lower Michigan during the late afternoon and evening hours. These storms are expected to congeal into an MCS and sink south towards northern Indiana and western Ohio by Monday evening. Damaging wind gusts remain the primary threat in thunderstorms that move into the forecast region Monday evening. The SPC continues to highlight the entire area in a Slight Risk (Level 2 of 5) for severe weather with a corridor of higher probabilities for damaging wind gusts extending across the western two-thirds of the forecast area.

Showers and thunderstorms remain possible on Tuesday while the surface low slowly exits the the east. We'll begin to dry out by Wednesday as high pressure gradually enters from the west. The exception will be a few showers across Northeast Ohio and Northwest Pennsylvania on Wednesday in lingering troughing over the lake.

AVIATION /12Z Sunday THROUGH Thursday/

An MVFR stratus deck has developed and will envelop the western terminals this morning into the early afternoon hours today before scattering out and lifting above FL030. Otherwise, cumulus field to develop again with isolated showers/storms to pop up, but far too low in chances for mention even in a PROB30 or TEMPO and leaving them out for now. Will need to watch convective complexes tonight moving in from the northwest, but look for those to fall apart on their way into the southern Great Lakes, although SHRA could remain. Winds WSW/W at 5-10kts.

Outlook...Non-VFR possible with periodic showers and thunderstorms Monday morning through Tuesday.

MARINE

West southwest winds today 10kts lead to waves around 1ft, with southwesterly winds picking up Monday into Monday night. Nearshore zones will stay below 2ft for wave heights in those periods, but a cold front coming through late Monday night into Tuesday morning will bring winds out of the north 15-25kts, and a Small Craft Advisory is likely to be needed with wave heights 3-5ft through Wednesday night. Wind speeds out of the north decrease to 10-15kts Thursday with wave heights gradually decreasing as well below SCA criteria with light and variable winds expected Friday, and wave heights finally less than 2ft.

There is a thunderstorm potential beginning late today through Tuesday morning.

CLE WATCHES/WARNINGS/ADVISORIES

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