textproduct: Cleveland

WHAT HAS CHANGED

The forecast remains largely unchanged compared to this morning's full update. A Winter Weather Advisory remains in effect for Crawford and southern Erie Counties in NW PA from 7 PM this evening to 1 PM EST Wednesday.

KEY MESSAGES

1.) A clipper-type low pressure system is still expected to deliver a widespread accumulating snow to our region this evening into early Wednesday morning. Greatest snow accumulations are still expected in NW PA.

2.) A progressive weather pattern is expected on Wednesday through next week Tuesday. It will include bouts of below-normal and above-normal air temperatures.

DISCUSSION

1.) A high pressure ridge at the surface and aloft continues to exit E'ward through this evening. During this evening through daybreak Wednesday, a shortwave trough axis aloft should move from the western Great Lakes and vicinity to near western NY and western PA. Just ahead of the shortwave trough axis aloft, a very weak surface cold front will traverse our region. Moist isentropic ascent ahead of the shortwave trough axis aloft is expected to allow widespread snow to blossom over our CWA between roughly 8 PM and midnight tonight. The aforementioned cold front should sweep generally E'ward through our region between about midnight and daybreak Wednesday morning. Low-level convergence/moist ascent along the front will likely act as a focus for the development of additional snow showers. Given the expected progression of the surface cold front and shortwave trough axis aloft, the widespread snow should end generally from west to east between midnight and roughly daybreak Wednesday morning as both features are followed by stabilizing subsidence accompanying another ridge that will build from the west. The snow is expected to be moderate to heavy at times, even outside the Winter Weather Advisory, since the moist isentropic ascent should be moderate to strong and maximized in a cloudy DGZ ~1 km deep, or at cloud temperatures just colder than the DGZ, for at least an hour or two. The longest-duration heavier snow, which should last for several hours, is expected to impact NW PA. As a result, snowfall totals are expected to reach 2-5" in NW PA, 1-3" in NE OH, and mainly 1" or less elsewhere in our CWA. Overnight lows should reach the lower 20's to lower 30's.

2.) W'erly flow aloft is expected over northern OH and NW PA on Wednesday through Friday night. Wednesday through Wednesday night should be mainly dry as stabilizing subsidence accompanies the aforementioned ridge at the surface and aloft that should continue to build from the Upper Midwest and vicinity. Peeks of sunshine should contribute to high temperatures reaching the mid 30's to mid 40's Wednesday afternoon. For context, normal highs are near 40F and normal lows are near 25F this time of year in our CWA. Continued net low-level CAA behind the above- mentioned cold front should contribute to the development of light lake-effect snow (LES) showers over Lake Erie and extending generally E'ward across the primary snowbelt of NE OH and NW PA. The LES should end around midnight Wednesday night as drier air at the surface and aloft arrives from the west and a lowering subsidence inversion causes lake-induced CAPE to wane significantly. This LES should yield fresh snow accumulations of 1" or less. Lows should reach mainly the mid teens to lower 20's around daybreak Thursday morning. Latest odds now favor dry weather on Thursday through Friday night as the ridge at the surface and aloft should eventually crest E'ward across our region. Rather abundant sunshine and the development of net low- level WAA on the backside of the surface ridge axis should allow late afternoon highs to reach the lower 30's to lower 40's on Thursday and the lower 40's to lower 50's on Friday. Overnight lows should reach the upper teens to mid 20's Thursday night and the 30's Friday night.

W'erly flow aloft should persist over our region this weekend through next week Tuesday. At the surface and aloft, the polar front should waver in/near the Great Lakes region and Upper OH Valley as multiple mid-latitude cyclones develop/evolve along the front. Periods of precip, mainly in the form of rain and/or snow are expected, especially Saturday night through Tuesday, along the front and ahead of shortwave trough axes embedded in the flow aloft. On Saturday, highs should reach the lower 40's to lower 50's amidst low-level WAA ahead of a late-day cold front passage. Mainly colder-than-normal temperatures should impact our region Saturday night through Monday night. On Tuesday, a warm front may sweep generally N'ward through our region and allow our highs to be near-normal.

AVIATION /00Z Wednesday THROUGH Sunday/

Widespread VFR conditions under high pressure will quickly diminish to MVFR/IFR as another clipper system moves through the region. Snowfall, moderate to heavy at times, will begin to impact terminals around 03Z/Wed and spread southeastward reaching SE terminals by 06Z/Wed. Visibilities will generally fall to MVFR with isolated areas of IFR to LIFR visibilities in heaviest snowfall. Highest likelihood of IFR to LIFR will be located across eastern terminals (KCAK/KYNG/KERI). Expect for VFR ceilings to return to western terminals early Wednesday morning. Elsewhere, MVFR ceilings will linger into Wednesday afternoon.

Southerly to southwesterly winds 12-15 knots with gusts 20-25 knots are expected to continue this evening. Winds turn westerly and will increase to 12-18 knots sustained with gusts up to 30 knots as the cold front moves across the region tonight.

Outlook...Non-VFR possible in lingering light snow showers across Northwest Pennsylvania during the day Wednesday. Additional non-VFR possible in light snow as another disturbance crosses the area Thursday.

MARINE

Southwest flow will increase across Lake Erie this afternoon with winds of 20-25 knots expected by 06Z as a strong cold front pushes southeast. Generally, these winds will persist into Wednesday, although slightly weaker winds are possible across the eastern basin. High pressure will nudge over the area Wednesday night, shifting winds to be from the west-northwest at 5-15 knots. Winds become more variable at 5-10 knots Thursday afternoon as a low pressure system moves south of the area. On Friday, there should be a high pressure system over the area with increasing winds on the western fringe from the southwest. Current forecast increases winds to 20-25 knots ahead of a cold front expected Friday night into Saturday.

While Small Craft Advisories remain suspended due to extensive ice coverage across the majority of the lake, waves in ice free areas may build to 3 to 6 feet during periods of stronger winds. Any wind shifts and elevated winds will result in movement of lake ice, which could impact shipping lanes.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...Winter Weather Advisory until 1 PM EST Wednesday for PAZ002- 003. MARINE...None.