textproduct: Cleveland

WHAT HAS CHANGED

Our forecast high and low temperatures have trended warmer prior to Wednesday's strong cold front passage. Severe convective weather concerns are increasing, especially for Tuesday afternoon through Tuesday night. Please see discussion below and SPC's convective weather outlook for more info.

KEY MESSAGES

1.) Active weather returns tonight and especially Tuesday through Wednesday. Severe thunderstorms are possible on Tuesday into Wednesday.

2.) Primarily colder temperatures and additional periods of unsettled weather are expected later this week through Monday.

DISCUSSION

KEY MESSAGE 1...

Cyclonic SW'erly to W'erly flow aloft and embedded shortwave disturbances affect our region through Wednesday night as a primary mid/upper-level trough deepens and approaches our region from the west. At the surface, a strong cold front continues to approach from the northern Great Lakes and Upper MS Valley before essentially stalling in vicinity of the southwestern Great Lakes, southern ON/Lake Erie, and the QC/New England border tonight through Tuesday night as multiple, weak lows move NE'ward along the front, which will cause the front to waver somewhat. On Wednesday through Wednesday night, a stronger low is still expected to deepen as it tracks NE'ward along the front, from the southwestern Great Lakes to southern QC. This evolution of the low should allow the trailing and strong cold front to sweep SE'ward across our region late Wednesday afternoon through the evening. Behind the front, a surface ridge builds from the north-central United States through daybreak Thursday. Net low-level WAA in the warm sector will contribute to overnight lows reaching the upper 40's to 50's tonight and the 50's to lower 60's Tuesday night, which will be well-above average for this time of year. Afternoon highs should reach mainly the upper 60's to lower 70's on Tuesday and Wednesday, respectively. Near- record warm high temperatures are expected on both days. Strong low- level CAA behind the cold front will contribute to lows reaching the mid 20's to lower 30's around daybreak Thursday.

Fair weather persists for the time being as a surface ridge continues to exit SE'ward from our region, ahead of the aforementioned front, and is accompanied by stabilizing subsidence. Overnight tonight, especially after midnight, isolated showers may blossom over our CWA, especially over and near Lake Erie, as a low- level return flow of warm/humid air originating over the Gulf undergoes isentropic ascent aloft and the development of a nocturnal low-level jet (LLJ) in roughly the 850-700 mb layer strengthens the moist isentropic ascent. This ascent may release weak, yet sufficient elevated CAPE to generate a few thunderstorms, especially west of roughly I-71. The effective inflow layer is expected to become surface-based in our CWA by late Tuesday morning and then remain so ahead of Wednesday's cold front passage as strong low- level warm/moist air advection from the Gulf continues and intervals of sunshine/daytime heating occur from shortly after daybreak through the afternoon on Tuesday and Wednesday, respectively. Periods of scattered showers and thunderstorms are expected Tuesday through Wednesday, ahead of the cold front. In addition, an extensive line of showers and thunderstorms should accompany the front itself. Weak to moderate CAPE, including elevated CAPE, is expected to be released by the following: low-level convergence/moist ascent along the surface front and pre-front surface trough axes accompanying the aforementioned shortwave troughs aloft; moist isentropic ascent preceding the shortwave trough axes and along the upper-reaches of the front. This isentropic ascent is expected to be enhanced by renewed LLJ development in roughly the 925-850 mb layer Tuesday evening through mid-morning on Wednesday. Tropospheric winds increasing significantly with height will contribute to moderate effective bulk shear tonight and then moderate to strong effective bulk shear Tuesday into Wednesday. Accordingly, organized severe thunderstorms in the form of multicells and supercells capable of producing damaging hail and straight-line wind gusts, respectively, are possible Tuesday through Wednesday, along and ahead of the cold front. Greatest potential for damaging hail should exist Tuesday afternoon through Tuesday night, when steeper mid-level lapse rates should contribute to larger MUCAPE in the hail growth zone and overlap favorable atmospheric melting levels spatially. The greatest potential for damaging wind gusts should exist Tuesday afternoon through early evening and again Wednesday afternoon through early evening, as diurnal convective mixing of the boundary layer yields steep low-level lapse rates, moderate DCAPE, and little or no DCIN. Note: a mesocyclonic tornado or two is possible late Tuesday afternoon into the predawn hours of Wednesday morning amidst favorably-low mixed layer LCL's and sizable surface-based ESRH stemming from low-level winds veering/strengthening significantly with height in vicinity of the surface front, which may be draped near the southern shore of Lake Erie on most of Tuesday afternoon into the early evening. Then during Tuesday night, the LLJ development should yield greater low-level wind shear and surface- based ESRH amidst continued favorable mixed layer LCL's, especially in NW OH. Additional note: showers and storms are expected to produce periods of heavy rain as the low-level warm/moist air advection from the Gulf yields near-record high PWAT values, especially during the day on Tuesday into Wednesday. Training convection is expected along the front as mean mid-level flow exhibits a large component parallel to the front. Excessive rainfall and localized flash flooding are not out of the question. Once the cold front sweeps SE'ward through our region, rain may mix with and then change to wet snow via nocturnal cooling, the wet-bulb effect, and strong CAA at the surface and aloft before precip along the upper-reaches of the front exits our region. Any snow accumulations should be less than a half inch.

KEY MESSAGE 2...

Dry weather and much colder air temperatures are expected in the cold sector on Thursday as the surface ridge continues building E'ward, a primary trough axis aloft sweeps E'ward over our region, and shortwave ridging aloft follows. Daytime highs should reach only the 30's in NW PA and the mid 30's to mid 40's in northern OH. The ridge exits E'ward Thursday night and allows a warm front to sweep N'ward through our region as a clipper-type low pressure system approaches from the north-central United States and vicinity. A mix of primarily rain and snow is possible via moist isentropic ascent along the upper-reaches of the warm front. Lows should reach the mid 20's to lower 30's before midnight and be followed by moderating temperatures as WAA strengthens at the surface and aloft ahead of and especially behind the surface warm front. As the clipper moves E'ward across the northern Great Lakes region on Friday, the trailing cold front sweeps E'ward across our region. Rain showers along the surface cold front may be followed by a rain/snow mix associated with the upper-reaches of the cold front as cold air deepens behind the surface front. Daytime highs are expected to reach mainly the 40's to lower 50's ahead of the cold front. Odds favor dry weather Friday night as a ridge at the surface and aloft moves E'ward through our region. Lows should reach the 20's to lower 30's amidst low-level CAA behind the cold front.

Primarily SW'erly to W'erly flow aloft and embedded trough axes should impact our region this weekend through Monday. At the surface, our region should mainly be located in the cold sector, but a warm front should sweep N'ward through our region Saturday night into Sunday and be followed by the E'ward passage of a strong cold front later Sunday into Sunday night. Additional periods of rain and/or snow are expected courtesy of the front passages and moist isentropic ascent ahead of the trough axes aloft. Mainly near or below-average air temperatures are expected, but above-average high temperatures are forecast in the warm sector on Sunday.

AVIATION /18Z Monday THROUGH Saturday/

VFR conditions will continue through at least 03Z with breezy southwest winds gusting to 25 knots through sunset. Clear skies persist this afternoon with clouds expanding this evening and lowering to MVFR late tonight. There is some potential for patchy drizzle or a few showers to develop in 10-18Z time frame but these are hard to time at any given location so mainly have vicinity showers in the TAFs. There is potential for IFR conditions after 12Z Tues as low level moisture ramps up, especially closer to Lake Erie. There will also be marginal low level wind sheer conditions late tonight with winds near 2000 feet of around 35 knots but not quite sufficient to need to add to the forecast. Chances for showers on Tuesday will become focused closer to Lake Erie but could clip TOL/CLE/ERI towards the end of the TAF period.

Outlook...Non-VFR likely with showers and thunderstorms Tuesday night into Wednesday followed by rain briefly transitioning to snow Wednesday night into Thursday. Non-VFR may return in scattered rain/snow showers on Friday combined with gusty southwest winds.

MARINE

Breezy southwest winds of 10-20 knots on Lake Erie continue into tonight. A weak frontal boundary settles south across the lake late Tuesday with winds shifting out of the east. Thunderstorms are possible in and near Lake Erie Tuesday night along this boundary and may interfere with wind conditions into Wednesday. Winds on Wednesday are forecast to increase into the 15-25 knot range ahead of low pressure that will cross the lake, veering to west/northwest behind a cold front Wednesday night into Thursday. Waves will ramp up to near 5 feet in ice free portions of the central basin Wednesday night.

Another strong low pressure system is forecast to pass north of Lake Erie on Friday. Winds could approach gale force on Friday and the track and strength of this system will need to be monitored.

CLIMATE

Daily high temperatures are forecast to approach records through March 11th. Here are the record warm high temperatures at area climate sites for March 10th and 11th.

Date Toledo Mansfield Cleveland Akron Youngstown Erie 03-10 72(2021) 72(1973) 72(1973) 73(1973) 69(2021) 72(2021) 03-11 76(1990) 72(1990) 73(1977) 72(1977) 70(1977) 72(2021)

CLE WATCHES/WARNINGS/ADVISORIES

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