textproduct: Cleveland

WHAT HAS CHANGED

The rainfall forecast has trended higher for portions of NE OH/NW PA Sunday. However, confidence in the location of the heaviest rainfall and the resulting greatest flooding risk is still relatively low at this point.

KEY MESSAGES

1) Several rounds of rain with some thunderstorms are expected through Sunday. Heavy rainfall will be possible at times with some flash flooding potential on Sunday. Isolated strong to severe storms are also possible Sunday afternoon into Sunday evening.

2) Periodic scattered rain chances and near normal temperatures are expected next week.

DISCUSSION

KEY MESSAGE 1... Low pressure will slowly shift east across the Midwest through Sunday, bringing multiple rounds of rain to the local area for the rest of the weekend. Any precipitation this afternoon into the start of this evening will be light, although rainfall rates will likely pick up as better moisture lifts into the area tonight. A few thunderstorms can't be ruled out, but severe weather is not anticipated tonight. By early Sunday morning, most spots across the area will see at least a quarter of an inch of rain with locations along and west of I-75 likely receiving up to 0.75" of rain. There are some signals for training and locally higher amounts of 1-2" along the far western fringe of the local area, although that higher precipitation axis may be to the west of the CWA. Will need to keep an eye on where swaths of heavier rain occur, but in general this initial round of rain will largely serve as a primer for heavy rainfall on Sunday.

A break in precipitation (or at least, lower coverage in shower activity) is likely Sunday morning, especially across north- central Ohio. By the afternoon, better upper level support will move over the region, allowing additional showers and thunderstorms to develop and move east through the rest of the afternoon and into the evening. This will be the window for the heaviest rainfall and likely the greatest flash flooding risk. Most of the area will receive 0.5 to 0.75" of additional rainfall Sunday afternoon/evening with some areas possibly receiving 2 or more inches of rainfall where showers and thunderstorms train. Latest guidance suggests that the highest rain amounts could fall across portions of NE OH/NW PA which would result in an enhanced flash flooding risk, but will need to see how high res models trend over the next 12-18 hours. Have opted against issuing a Flood Watch with this update since confidence in the placement of the heaviest rainfall/greatest training potential is still medium at best. Would like to see where the heaviest rain occurs tonight before making a final decision on any headlines. On Sunday, there is a Slight Risk (Level 2 of 4) of excessive rainfall/flash flooding across the majority of the local area.

There is still potential for isolated strong to severe thunderstorms Sunday afternoon into Sunday evening. Jet support will increase Sunday afternoon as the low meanders eastward into the Ohio Valley, resulting in increased shear. There's still some uncertainty with how much we destabilize given the potential for morning showers/thunderstorms. If we manage to clear out between rounds of rain then instability will be higher, but any lingering showers/clouds could result in lower instability and a lower severe weather threat. Based on the shear profile/wind field, any thunderstorms could produce damaging wind gusts and possibly a brief tornado Sunday afternoon/evening. There is a Marginal Risk (Level 1 of 5) of severe weather.

KEY MESSAGE 2... The low will finally lift northeast of the area on Monday, although persistent upper troughing will result continued chances of rain showers through much of Monday. A brief period of dry weather is anticipated on Tuesday before rain chances increase as a shortwave lifts into the region Wednesday. Scattered rain chances continue through the end of the week as an upper trough shifts east into the area Thursday/Friday. Temperatures will generally be near normal with highs in the 80s and lows in the 60s anticipated.

AVIATION /18Z Saturday THROUGH Thursday/

Low pressure moving into the area brings scattered SHRA/TSRA, and the challenge for the forecast was the timing at each terminal. Tried to limit the TSRA as much as possible in the end and keeping restrictions within MVFR, but a stronger cluster of storms may require /AMD to IFR visibilities briefly. Ceilings will lower from MVFR and likely to IFR in places by dawn Sunday.

Outlook...Occasional non-VFR in showers and thunderstorms into Sunday night. Isolated to scattered showers and thunderstorms with potential for non-VFR continue Monday through Wednesday, primarily during the afternoon hours.

MARINE

Low pressure will move west to east south of Lake Erie tonight into Sunday, with winds becoming northeasterly around 10kts tonight, increasing to 15-20kts Sunday and Sunday night. Western and central basin wave heights will increase to 3-5ft Sunday night, decreasing to 1-3ft as northeasterly winds persist through Tuesday. Winds turn light and variable Wednesday with wave heights less than a foot.

CLE WATCHES/WARNINGS/ADVISORIES

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