textproduct: Cleveland

WHAT HAS CHANGED

Issued a new Flood Watch for portions of the area today. This watch covers a combination of periods of heavy rain continuing to stream off of Lake Erie into parts of Northwest Ohio through this morning and into this afternoon, along with expected scattered to numerous afternoon showers and storms farther east across portions of North Central and Northeast Ohio.

KEY MESSAGES

1) Showers and thunderstorms are streaming off of western Lake Erie into parts of Northwest Ohio this morning, with activity expected to blossom elsewhere across the area this afternoon and evening. Locally heavy rainfall and flash flooding remain concerns and a Flood Watch is in effect for parts of the area.

2) The next chance for showers and thunderstorms will be Thursday into Friday as the next cold front moves through.

DISCUSSION

KEY MESSAGE 1... The weak, stacked low-mid level low that drifted into the region on Sunday remains with us today before slowly exiting to the east-southeast tonight and Tuesday, providing for one more day of rather unsettled conditions across the area.

The focus to start the day is from Lake Erie into parts of Northwest Ohio. A surface trough is over the lake, focusing cooler, convergent east-northeast low-level flow north of the low pressure currently located between Findlay and Mansfield. The warm lake waters are providing for a pool of instability that is extending into Northwest OH and has been fueling lake- enhanced showers and thunderstorms with very efficient rain- rates overnight. Most hi-res models suggest this activity will continue at times through at least this morning and quite possibly into the afternoon...especially if models like the HRRR, which has captured this overall setup well, prove correct. Given the general setup doesn't change until this afternoon when the trough axis starts shifting south and instability over the lake begins decreasing, expect this activity to continue in some fashion with embedded efficient/torrential rain rates.

The most torrential rainfall overnight has been over the lake, but has impacted Kelleys Island where radar and a few personal weather stations suggest 10-15" of rain has fallen since about 9 PM. Peak hourly rates of over 5" per hour were observed. Even on the mainland, a slow-moving cluster of showers and storms has dropped a quick 2-3" of rain on parts of eastern Wood County early this morning. Most hi-res models suggest at least another localized 2-4" of rain can occur within lake enhanced convection through the afternoon, with some models such as the HRRR depicting potential for localized 5"+ totals. Given the model signal, portions of the area seeing heavy rain on Sunday, and observed rain rates overnight have gone with a Flood Watch for Lucas, Wood, Ottawa, Sandusky, Erie, and Huron Counties until 6 PM to advertise the continued potential for localized flash flooding. Rain totals will likely be sporadic across the watch area...the greatest concern would be if slow-moving or training convection impacts the more urban Toledo area or places that have otherwise seen heavy rain over the last 24 hours.

Elsewhere, we are starting mainly dry this morning. The trough axis over the lake is expected to push onshore across North Central and Northeast Ohio later this morning or early this afternoon and gradually sag south-southeast across the region through this evening. While activity may not be especially focused or organized, decent coverage of showers and thunderstorms is expected this afternoon and early evening along the trough axis from parts of North Central Ohio points east- southeast across much of Northeast Ohio. Skinny instability profiles and elevated precipitable water values of 1.60-1.80" inches will support efficient rain-rates with convection, with generally weak west flow aloft supporting slower storm potions and potentially a bit of training along the sagging trough axis. This adds up to potential for locally heavy rainfall and flash flooding once again. The model signal is somewhat mediocre for heavy rain, likely due to the fairly modest forcing. Models that seem to be capturing the setup best and handled Sunday's setup better, such as the HRRR and 3km NAM, have decent coverage of convection with localized 2-4" QPF bullseye across portions of North Central and Northeast OH this afternoon and evening. With parts of the area more prone to run-off after Sunday's rain and in collaboration with neighboring offices, hoisted another Flood Watch from 11 AM to 11 PM from Lorain and Mansfield points east through the Cleveland, Akron, Canton and Youngstown areas. A somewhat marginal watch, but if torrential rates impact an urban area or places that saw heavy rainfall on Sunday localized flash flooding could quickly develop.

In terms of any severe weather potential today, we are not outlooked by the Storm Prediction Center and are not expecting any sort of an organized severe weather threat given skinny, somewhat marginal instability profiles and rather limited amounts of vertical wind shear due to modest flow aloft. If there is one thing to consider, it is that the low in the region will provide for plenty of low-level vorticity, particularly along the surface trough axis that will sag across the area this afternoon and evening. With strong low-level instability expected, a few stronger updrafts may stretch low-level vorticity into the vertical and attain transient rotation. If anything, this would encourage larger, slower-moving updrafts that provide greater concern for heavy rain. If we see any more sustained rotating updrafts as we did on Sunday the concern for locally gusty winds and perhaps a funnel cloud/low end tornado would be there. Overall, this seems to be on the less likely side unless we see a convectively aided vort max or meso-low develop like we did on Sunday.

We will largely dry out tonight, though can't rule out a few lingering showers across southern/eastern portions of the area closer to the departing low. Isolated to widely scattered showers, and perhaps a storm, will likely develop with daytime heating on Tuesday across eastern/southeastern portions of the area. Coverage should be much less than recent days with no real concern for any severe weather or additional flooding. Tranquil conditions are expected Tuesday night through early Thursday.

KEY MESSAGE 2... The next cold front approaches from the northwest late Thursday and Thursday night and crosses the area Friday morning and early afternoon. Renewed shower and storm chances enter on Thursday ahead of the front and linger into Friday. Weak mid-level lapse rates and fairly modest flow aloft point to a lower-end potential for severe weather if anything. However, will still keep an eye on the setup as we get closer, especially if we're able to see convection ahead of the front closer to peak heating hours Thursday afternoon or evening.

AVIATION /12Z Monday THROUGH Friday/

The main message for aviation weather will be scattered showers and thunderstorms today with variable flying conditions around convection impacting TAF sites. A weak low pressure system will track eastward across the area today with pockets of heavier convection expected to impact TAF sites over northeast Ohio and NWPA. The general expectation is MVFR ceilings and conditions outside of convection today into this evening. PROB30 groups highlight a 6 hour window where convection is possible to bring at least IFR conditions if not briefly LIFR weather today. IFR ceilings may return for MFD, CLE, CAK, YNG, and ERI later tonight through sunrise Tuesday. Winds will be variable around the weak surface low tracking across the area today. Easterly to northeasterly winds around 8 to 12 knots expected north of the surface low track. Southeasterly to southerly winds 5 to 10 knots expected south of the low track.

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

MARINE

A meso low is currently over the western basin of Lake Erie this morning. This surface low will track slowly eastward today moving on shore near the Cleveland area. East to northeast flow will persist over the lake today 10 to 20 knots. Waves over the western and central basin will be up to 4 feet and has prompted a Small Craft Advisory and associated beach hazard statements for a high risk of rip currents through early evening. A small area of convection over the western basin of Lake Erie associated with the meso low may produce waterspouts through the morning hours. A residual weak surface trough may linger over the Upper Ohio Valley Tuesday into Wednesday which would continue a northeasterly to northerly flow 8 to 15 knots over Lake Erie. A weak area of high pressure will briefly build into the area Thursday with a southwesterly flow 5 to 10 knots. A cold front will move across the area Friday with a northwesterly flow around 10 knots behind it. No other marine headlines are expected for the rest of the week beside today.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Beach Hazards Statement through this evening for OHZ003-007- 009. Flood Watch until 6 PM EDT this evening for OHZ003-006>009-019. Beach Hazards Statement from 11 AM EDT this morning through this evening for OHZ010-011. Flood Watch from 11 AM EDT this morning through this evening for OHZ010>013-020>023-029>033. PA...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for LEZ142>144. Small Craft Advisory from 11 AM this morning to 10 PM EDT this evening for LEZ145-146.