textproduct: Cleveland

WHAT HAS CHANGED

Lake-effect snow (LES) is shifting N'ward over/downwind of Lake Erie and the primary snowbelt of NE OH and NW PA as the mean low-level flow of sufficiently-cold/moist air backs to W'erly and eventually backs to SW'erly. Expect this LES to weaken, overall, during the next several hours and dissipate very early this afternoon as lake-induced CAPE wanes via a lowering/strengthening subsidence inversion accompanying a surface ridge cresting E'ward across our region as the portion of the ridge aloft continues to build from the west. Additional LES accumulations are expected to be one inch or less.

KEY MESSAGES

1) Lake-effect snow will taper off early this morning. After a brief break through this afternoon, a clipper system will enter the region and bring additional light snow areawide with several inches of new accumulation expected NW PA.

2) A system will move through the Ohio Valley on Thursday and may bring additional snow to the region. Trends with this system remain south and the heaviest snow may miss the local area.

DISCUSSION

KEY MESSAGE 1... Light lake-effect snow continues across the region this morning. With the persistent Lake Huron connection into the region, expect another inch or two of snow to fall through 7 AM, mainly in the hills of NW PA. Trends should be down after daybreak, as clouds are falling apart over Lake Erie and mean low level flow should begin backing across the region.

There will be a brief break in the snow later this morning into the afternoon before a clipper system moves through the Great Lakes region. Snow will begin after dark and bring light accumulations to the entire forecast area. In far NE OH and NW PA, snow will be quick to ramp up tonight with a quick 2-4+" of snow in a brief 4 to 6 hour window. Have gone ahead an issued the new Winter Weather Advisory for southern Erie and Crawford Counties in PA from 7 PM tonight to 1 PM Wednesday. Some lake-effect snow will linger into Wednesday in PA for some additional light accumulations.

KEY MESSAGE 2... The next system in the sequence is a low pressure system moving through the Ohio and Tennessee Valleys on Thursday. This system has continued to trend south, meaning that the precipitation shield on the north side of the system is also trending south. As of this morning, the forecast will have the main snow axis of a couple inches of snow shifting south, mainly along and south of US 30, but several 00z guidance members are suggesting that this axis may go even further south and most of the area may actually miss having any snow with this system.

AVIATION /18Z Tuesday THROUGH Sunday/

A few lingering light snow showers remain across NEOH and NWPA as the associated trough continues to push east. These snow showers are no longer causing reductions to visibilities, however widespread MVFR ceilings are being reported across the area. As the ridge becomes more dominant this afternoon, there should be a brief period of VFR conditions at all terminals, but they will be short lived as another clipper system impacts terminals tonight. Snowfall chances begin to increase near 03Z in NWOH before spreading southeast across the entire area. Visibilities will likely drop to MVFR distances with this clipper with a non-zero chance of IFR/LIFR visibilities where the heaviest bands persist. Most terminals will remain non-VFR through the period with far western terminals possibly rebounding to VFR by late Wednesday morning.

Southwest winds today will increase to 12-15 knots along and west of I71 with gusts up to 25 knots possible. As the cold front approaches after 00Z tonight, winds will increase across the entire area to 12-17 knots, gusting up to 25-30 knots. Locally higher gusts are possible at KERI due to downslope enhancement. As the front pushes east Wednesday morning, winds will weaken to 10-12 knots before increasing once again Wednesday afternoon.

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 from 7 PM this evening to 1 PM EST Wednesday for PAZ002-003. MARINE...None.