textproduct: Cleveland

WHAT HAS CHANGED

A chance for some showers has been introduced to the forecast for Wednesday evening/night with a warm frontal passage.

KEY MESSAGES

1) Dry and pleasant weather continues through Wednesday.

2) Some showers possible Wednesday night, followed by greater potential for widespread rain late Thursday into Friday.

3) Cooler weather this weekend into early next week. This period will be mainly dry with a couple of minor rain chances.

DISCUSSION

KEY MESSAGE 1... Fantastic early fall weather continues midweek as we get into weak return flow behind departing high pressure. Any fog development tonight should be rather limited as a bit more of a gradient will likely allow most locations to hang onto a light breeze, though some valleys may still decouple and see patchy fog. Wednesday will feature an increase in clouds but should remain dry until the evening hours. Lows will generally dip into the 50s tonight, with the light south-southwest breeze keeping us a little milder than last night. The modest return flow will support slightly warmer highs in the mid-upper 70s on Wednesday.

KEY MESSAGE 2... A closed low (partially comprised of the remnants of East Pacific Hurricane Polo) will eject out of the Southwest and into the Plains Wednesday into Thursday, before shearing out/ weakening as it lifts towards the Ohio Valley on Friday. At the same time, ridging over the eastern U.S. will flatten as a shortwave moves through the northern Great Lakes and into New England, pushing a cold front southeast across the local area Thursday night into Friday.

A loosely defined warm front is expect to lift across the area late Wednesday into Wednesday night. Increasing mid-level moisture and some isentropic lift along/ahead of the warm front may support some rain showers late Wednesday through early Thursday, particularly across northern portions of the area. More models are indicating this potential than prior cycles, so have added some 20-40% type rain chances to the forecast. Rain amounts late Wednesday into early Thursday will generally be near or under 0.10", with locally up to 0.10-0.25" possible.

Much of the day Thursday will be dry in the open warm sector, with rain lingering early towards Northwest PA closer to the warm front and approaching from the northwest late in the day ahead of the cold front. The greatest window for rain will be from northwest to southeast Thursday night into Friday. There is some disagreement over how progressive the front will be, which will influence how rainy we are through the day Friday and overall QPF amounts. The current forecast leans a soggier direction for Friday, especially through the early afternoon, with some potential for northern portions of our area to dry out through the afternoon. Much of the area is expected to see 0.40-0.80" of rain Thursday night through Friday, with the greatest amounts expected across Northwest Ohio. Somewhat unintuitively, a slower front could lead to less overall QPF per ensemble members, as the overall system will be weakening with time. Regardless, ensembles suggest that a drier system producing as little as 0.20-0.50" overall is possible, with a more robust solution potentially dropping 1.00-1.50" in the Toledo area. Overall, this rain will be beneficial and should not pose a risk for impactful flooding falling on dry grounds.

Highs will push towards 80 on Thursday, our last day with such values for a while. Highs on Friday are forecast to range from the mid 60s to near 70, though that may be slightly misleading as highs will be early in the day ahead of the front, with temperatures holding steady or falling behind the front.

KEY MESSAGE 3... High pressure builds into the lower Great Lakes Friday night into Saturday behind the departing front, bringing a period of drier and somewhat cooler weather. Another potent shortwave is expected to dive through the Great Lakes and into New England Sunday and Monday, carving out a deeper trough over the Northeast. This will likely bring a re-enforcing/stronger cold front late Sunday or Monday that may be accompanied by a chance of showers, followed by an even cooler airmass the first half of next week. The overall airmass and high pressure strength may support a frost potential Monday night/early Tuesday, assuming favorable high placement for radiational cooling.

AVIATION /18Z Tuesday THROUGH Sunday/

VFR is expected through the TAF period with scattered mid-level cumulus likely at inland eastern terminals. Winds will be light and variable at most terminals through this evening, although a lake breeze will produce north/northwest winds to 5 to 10 knots at KERI and KCLE this afternoon into early this evening. Winds will become southerly at 10 knots or less at all terminals tonight with flow becoming a bit more southwesterly and increasing slightly during the day Wednesday.

Outlook...Non-VFR possible with rain showers Thursday night through the weekend.

MARINE

Southwesterly winds are expected to dominate tonight through Thursday ahead of a cold front that will cross the lake Thursday night. These southwest winds will increase to the 10-15kt range at times, including tonight/early Wednesday and Wednesday night through Thursday, building 1 to 3 footers in the open waters. Winds shift northerly on Friday behind the front and remain north-northeast through Saturday. The current forecast has 15-20kt winds and 2-4/3-5 foot type waves Friday through early Saturday, and as the prior discussion mentioned it's not uncommon for forecast winds to trend upwards behind good cold fronts in the early fall. Given that, there is elevated potential for Small Craft Advisories Friday into early Saturday. A brief period of calmer conditions is likely late Saturday into Sunday, with another push of stronger north-northwest winds behind a cold front early next week.

CLE WATCHES/WARNINGS/ADVISORIES

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