textproduct: Cleveland

WHAT HAS CHANGED

Saturday's Slight Risk for severe weather has been expanded to include the entire local area. There's still concern for localized flooding due to excessive runoff and/or additional rises on rivers thanks to multiple rounds of heavy rainfall through Saturday, although confidence in the location of the highest precipitation values and the resulting location of the greatest flooding risk remains somewhat low at this point.

KEY MESSAGES

1) Scattered showers and thunderstorms are expected along a frontal boundary across the area through tonight. A few storms may be strong to severe and produce damaging wind gusts/large hail. Additional minor flooding is possible due to heavy rainfall rates.

2) Confidence in organized thunderstorms is higher as a cold front moves across the area Saturday afternoon into Saturday night. Storms may be strong to severe and produce heavy rainfall.

3) Much cooler temperatures expected Sunday through the middle of next week with a few periods of precipitation possible.

DISCUSSION

KEY MESSAGE #1: Scattered showers with a few thunderstorms have developed south of the lakeshore, however a relatively strong capping inversion will most likely continue to prevent widespread efficient thunderstorm growth through the rest of this afternoon. Showers/thunderstorms will increase in coverage along a frontal boundary as better upper level support arrives this evening before lifting north with the boundary early Saturday morning. If any storms manage to grow tall enough, there is potential for isolated instances of damaging wind gusts and large hail through about 10 PM tonight. Otherwise, assuming the mid-level dry air doesn't throw a wrench into things, heavy rain will be the primary threat through late tonight with unseasonably high precipitable water values expected. Mean flow will be parallel to the frontal boundary, but the good news is storm motion will be progressive which will help mitigate training and the flash flooding potential. With that being said, antecedent conditions are conducive for at least minor flooding with 1 and 3 hour FFG under 2 inches in place across the majority of the area and high soil moisture values present across the eastern half of the local area. At this point, it's difficult to pinpoint the areas of greatest concern given uncertainty in where the highest QPF axis will occur tonight.

KEY MESSAGE #2: The local area will remain in the warm sector during the day Saturday, allowing dew points to rise into the upper 50s and lower 60s by the afternoon. Another round of showers and thunderstorms will develop as a cold front moves east into the area Saturday afternoon and crosses the area into Saturday evening. Showers and storms will be more organized with this round given the better upper-level forcing and higher effective bulk shear values up to 40 knots. The moist southerly flow and likely clearing early in the day will also result in MLCAPE values of 1000-1500 J/kg by mid afternoon. Storm mode will likely be line segments with damaging wind gusts being the primary threat. However, 0-1 km shear values of around 15 knots, the higher MLCAPE values, and LCL heights under 1000 feet will support at least a low-end chance of a few spinups/tornadoes. The Slight Risk (level 2 of 5) of severe weather has been expanded to include the entire CWA, meaning confidence in organized/stronger storms has increased a bit. Heavy rainfall will likely accompany the convection and the multiple rounds of heavy rain in just a couple of days may make it a bit easier for flooding to occur Saturday afternoon/evening. By early Sunday morning, two-day rainfall totals of about .75 to 1.25 inches will occur across the majority of the area with locally higher amounts certainly possible where the heaviest rainfall rates occur. Additional rises on area rivers are likely.

KEY MESSAGE #3: A pattern shift with colder temperatures is anticipated behind Saturday's cold front. Highs will be in the 40s and lower 50s Sunday and Monday with the coldest highs in the 30s and lower 40s expected on Tuesday. Periods of lake effect/enhanced showers are possible through early Tuesday and rain may mix with snow at times, especially Sunday night and Monday night. Temperatures will trend warmer for mid to late week and a period of widespread dry weather is expected late Tuesday through Wednesday before rain shower chance return on Thursday.

AVIATION /00Z Saturday THROUGH Wednesday/

Showers and thunderstorms will continue to bring periods of MVFR and even IFR conditions to KMFD, KCAK, and possibly as far north as KYNG over the next few hours. All other sites will be mainly dry and VFR. This axis of showers and thunderstorms will start to lift northward overnight and impact KTOL, KFDY, KCLE, and KERI, but confidence in the timing at each terminal is low. In general, think that the showers and thunderstorms will be near KFDY, KTOL, and KCLE in the 06-10Z timeframe, with it likely taking until 10Z or later to reach KERI. At the same time, the showers and thunderstorms will gradually lift out of KMFD, KCAK, and KYNG in the roughly 04-09Z timeframe. This timing is give or take an hour and will depend on the organization of the convection.

By mid morning Saturday, there will be a lull areawide before a line of showers and thunderstorms spreads in from west to east from mid afternoon through mid evening. Have showers and thunderstorms reaching KTOL and KFDY between 17 and 20Z and KYNG and KERI by 23Z. These storms could produce locally higher winds at each terminal, especially the NE Ohio terminals.

Winds will become generally E at 5-10 knots tonight, turning S and increasing to 10-15 knots Saturday morning as the warm front lifts north. Winds will turn SW and further increase to 15-25 knots, with gusts over 30 knots at times, by Saturday afternoon.

Outlook...Non-VFR with low ceilings may linger through Sunday. Non- VFR may return Monday and Monday night in rain and/or snow showers.

MARINE

Winds will briefly increase around 15 to 20 knots out of the east Saturday morning ahead of a lifting warm front, though the main marine concern continues to be on Sunday as a cold front ushers in west winds of 20 to 22 knots. A Small Craft Advisory will be needed on Sunday, especially across the central and eastern basins. In addition, strong winds may accompany some of the showers and thunderstorms along and ahead of the front on Saturday. A secondary cold front will cross the lake Monday night into Tuesday with confidence increasing for additional Small Craft Advisories as winds shift towards the north to northwest, 20 to 22 knots. Quieter marine conditions will return on Wednesday as high pressure builds across the region.

CLE WATCHES/WARNINGS/ADVISORIES

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