textproduct: Cleveland

WHAT HAS CHANGED

No significant changes to the previous forecast. Still anticipating a prolonged period of heat and high humidity this upcoming week.

KEY MESSAGES

1.) Periodic rain showers are expected and isolated thunderstorms are possible through this early evening.

2.) Warmer and more humid weather is expected this Sunday through Friday. Periodic showers and thunderstorms are possible, especially on Thursday and Friday.

DISCUSSION

KEY MESSAGE 1... W'erly flow aloft and embedded shortwave disturbances affect our region today before a high pressure ridge aloft begins to build from the Upper Midwest and vicinity tonight. At the surface, a front lingers in vicinity of the OH River Valley as multiple surface lows move generally E'ward along the front through tonight. Simultaneously, the surface portion of the aforementioned ridge builds slowly into our CWA from the western Great Lakes and vicinity. Scattered rain showers, steady to heavy at times, are expected through this afternoon courtesy of moist isentropic ascent associated with the warm conveyor belt of a primary low- level low along the aforementioned front. Periods of rain should be more-frequent roughly along and south of U.S. Route 30 since that portion of our CWA will be located closer to the surface front, frontal surface lows, and associated stronger synoptic-scale forcing for ascent. Isolated thunderstorms are possible late this morning into the afternoon since the isentropic ascent may release weak, yet sufficient and primarily elevated CAPE. Isolated to scattered showers and any isolated thunderstorms are expected to end generally from WNW to ESE late this afternoon through mid-evening as the warm conveyor belt exits generally E'ward and the ridge at the surface and aloft continues to build from the west. Additional rainfall should be 0.10" to 0.25" roughly along and south of U.S. Route 30 and 0.10" or less elsewhere in our CWA. Widespread dry weather is then expected through tonight amidst stabilizing subsidence accompanying the ridge.

Intervals of sunshine and sufficient daytime heating should allow highs to reach the 70's to lower 80's late this afternoon. The coolest highs are expected over and within several miles of ~70F Lake Erie due to lake breeze development late this morning through early evening. Overnight lows should reach the upper 50's to upper 60's around daybreak Sunday.

KEY MESSAGE 2... A warming trend and increase in humidity are expected this Sunday through Friday as the mid/upper-level ridge axis shifts from near the MS Valley to near the eastern Great Lakes and the Atlantic coast of the FL peninsula. This will cause our region to become located within a synoptic-scale low-level warm/moist air advection regime from the Gulf as we become located along the western flank of the surface portion of the ridge, especially starting on Monday. Daytime highs should reach the mid 70's to mid 80's on Sunday. On Monday, lows mainly in the 60's around daybreak should be followed by late afternoon highs mainly in the mid 80's to mid 90's. The coolest highs on Sunday and Monday are expected over and within several miles of Lake Erie due to lake breeze development each late morning through early evening. Maximum heat indices are forecast to be near 100F in NW OH, inland from Lake Erie, on Monday. Forecast trends will be monitored for the possible and eventual need for a Heat Advisory.

Tuesday through Friday should feature morning lows mainly in the 70's around daybreak and late afternoon highs mainly in the upper 80's to upper 90's. Daily maximum heat indices may reach the roughly 100F to 105F range in portions of our CWA. Stay tuned to forecast updates and possible hot weather alerts. However, the thermodynamic environment and synoptic-scale MSLP gradient should support Lake Erie lake breeze development each late morning through early evening, especially along and near the shore from northeastern Cuyahoga County through Erie County, PA. Thus, mesoscale refinements to the daily high temperature and maximum heat index forecast are likely in the coming days.

Current odds favor dry weather on Sunday through Wednesday night as relatively-strong and stabilizing subsidence associated with the ridge continues to impact our region. Occasional showers and thunderstorms are possible this Thursday through Friday as subtle shortwave disturbances ripple generally eastward through the ridge aloft, are accompanied by surface trough axes, and low-level convergence/moist ascent along the surface trough axes release at least weak to moderate instability. Some storms may be strong to severe as the aforementioned shortwave disturbances interact with the ridge aloft and tighten the isobaric height gradient aloft, which in turn should yield at least moderate deep-layer bulk shear.

AVIATION /06Z Saturday THROUGH Wednesday/

Shower activity has largely struggled over northern Ohio and Northwest PA early this morning with just some spotty showers with minimal impacts across the airspace. Some heftier rain showers may enter from the south later this morning and impact KMFD and KCAK with some non-VFR conditions but confidence is low in visibility dropping to non-VFR levels. The larger aviation impact will be some non-VFR ceilings spreading north into the airspace overnight and into the daytime hours on Saturday. Most terminals will see a drop to MVFR and a couple lucky spots could get some brief IFR ceilings. KCLE and KERI will largely remain VFR with dry, northeast flow trying to keep any issues away from these terminals. Rain will continue to focus south of the area later today and will opt for a dry TAF for this afternoon and beyond. Ceilings will improve to VFR and light northeast winds will continue into Sunday.

Outlook...Non-VFR possible in fog/mist on Sunday morning.

MARINE

With a trough over the Ohio Valley, northeast flow will continue over Lake Erie. Winds may pick up into the 10 to 15 kt range this afternoon as the pressure gradient of the trough tightens just a bit. Otherwise, high pressure will build from the north, starting tonight, and become centered across the eastern Great Lakes for Sunday. This will allow for light northeast flow to continue through the weekend. The high will shift east on Monday and allow a warm front to cross the lake. This will allow for southeast winds to take over the lake on Monday night. Winds will shift to the southwest for Tuesday and Wednesday in the warm sector of the warm front with winds averaging 10 kts. There are no marine headlines expected at this time.

CLIMATE

Hotter and more humid weather is expected this Monday through Friday. Record warm high temperatures may be challenged. Here are those records for each of our climate stations:

Date Toledo Mansfield Cleveland Akron Youngstown Erie 06-29 100(1952) 96(1934) 94(2012) 98(1952) 99(1933) 90(2021) 06-30 97(1953) 94(1970) 95(1941) 96(1913) 94(1942) 92(1930) 07-01 98(1931) 98(1931) 95(2002) 97(1931) 96(1931) 94(2018) 07-02 98(2011) 97(1931) 97(1954) 98(1931) 98(1931) 94(1963) 07-03 100(1911) 93(2020) 98(1949) 97(1911) 98(1898) 93(1934)

CLE WATCHES/WARNINGS/ADVISORIES

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