textproduct: Cleveland

WHAT HAS CHANGED

Confidence is slowly increasing for widespread accumulating snow on Sunday. Sub-zero wind chills will return on Friday and persist into early next week.

KEY MESSAGES

1) A widespread snow is expected today with the highest totals found across Northwest Pennsylvania. Temperatures will warm near or above freezing by this afternoon and evening, followed by a cold front and gusty winds later tonight.

2) A prolonged period of sub-zero wind chills is expected beginning this Friday and will likely extend into early next week.

3) We are continuing to monitor potential impacts across our area from a developing system across the southern CONUS this weekend. Confidence is slowly increasing for widespread accumulating snow on Sunday.

DISCUSSION

KEY MESSAGE 1...

A clipper system will bring a period of widespread snow from west to east across the area today. Generally light totals of 0.5 to 2 inches are expected along and ahead of a warm front as temperatures quickly warm into the low to mid-30s by this afternoon. Higher storm total snow amounts of 3 to 5 inches are expected across Northwest Pennsylvania into Thursday morning - a majority of which should fall this afternoon and evening with the warm front. Snow rates will generally range between 0.5 and 0.75 of an inch per hour, though brief 1 inch per hour rates cannot be ruled out, especially early this afternoon.

Light snow and/or freezing drizzle is possible late this evening across Northeast Ohio and Northwest Pennsylvania behind the warm front as mid- level moisture dries out. Snow should become the predominate precipitation type once again by late overnight into Thursday morning as mid-level moisture returns with a cold front passage. Winds have been trending higher in recent model runs behind the cold front tonight and will be something to monitor in the next forecast package, especially across Northwest Ohio and along the lakeshore where brief 40 to 45 mph wind gusts cannot be ruled out.

KEY MESSAGE 2...

A brief relief to the cold will arrive today as a clipper system moves east through the Great Lakes, lifting a warm front across the area and ushering in temperatures near or even slightly above freezing this afternoon and evening.

Looking ahead, a prolonged period of sub-zero wind chills is expected towards the end of the week into early next week as a strong cold front moves through the area on Friday. The coldest temperatures are expected late Friday into Saturday, with medium-high to high confidence (60 to 80%) for wind chills to drop below -15 degrees F. Ambient surface temperatures will also remain cold, with medium-high to high confidence (70 to 100%) for daytime high temperatures to be at or below 16 degrees F, especially on Friday and Saturday.

KEY MESSAGE 3...

Finally, we are keeping an eye on a developing system across the southern CONUS this weekend and its potential impacts to our area. Confidence in a widespread accumulating snow continues to increase, with medium confidence (40 to 50%) for at least 2 inches of snow, up from 10 to 20% in last night's model cycle, particularly east of the I-71 corridor. Probabilities remain low to medium low (20 to 30%) for at least 4 inches of snow, though the overall synoptic pattern suggests this upward trend may continue with plenty of moisture and cold air in place.

AVIATION /06Z Wednesday THROUGH Sunday/

Not too many changes with the aviation forecast and the 06z TAF package. A warm front approaching the region will bring mid- level clouds overnight and then some snow showers with lower VFR ceilings by morning. Winds will also increase with 20 to 30 kt wind gusts in the warm sector during the daytime hours today. There will be a fall to MVFR later this morning into the afternoon as snow intensity will increases and MVFR ceilings enter. There could be some periods of IFR visibility in heavier snow during the afternoon hours and that would be largely limited to KERI. There will be a break in the snow before a cold front enters later on today and additional lake enhanced snow will impact mainly NE OH and NW PA. Ceilings will continue to fall during the afternoon and evening and would not be surprised to see some IFR ceilings across the eastern half of the area. The snow will largely exits this evening with just some residual snow showers in NW PA and extreme NE OH late in the TAF period.

Outlook...Non-VFR in lake effect snow impacting NE OH and NW PA Wednesday night through Friday. Areawide light snow and non-VFR are possible on Saturday night into Sunday.

MARINE

Marine weather conditions will continue to be rough with strong gusty winds through the end the week. Currently the western third of Lake Erie is now mostly ice covered as well as the nearshore water from Cleveland eastward to northwest Pennsylvania. Open water in the central and eastern basin of Lake Erie still remain at this time. Another low pressure system will move across the Great Lakes region today into tonight with a cold frontal passage. Winds will increase again this morning 15 to 25 knots from the southwest. Behind the cold front tonight, winds will be westerly 20 to 30 knots. We may have a short time period late tonight into Thursday morning with winds approaching Gales over the central and eastern basin. Westerly winds will continue 15 to 25 Thursday into Thursday night. Another Arctic cold front will sweep across the Great Lakes late Thursday night into early Friday morning with winds shifting northwesterly 15 to 25 knots through Friday night. Waves heights will increase with very rough conditions out over the open and ice free water of the central and eastern basin today through Friday night. There is the potential that water levels in the far western basin may drop again near or below the critical mark for safe marine navigation due the stronger southwest to westerly winds later today through Thursday.

A strong Arctic high pressure system will build over the Great Lakes Friday through Saturday night. Winds will actually decrease to around 10 knots under that high pressure early in the weekend. A potential storm system and low pressure system will move into the Ohio Valley and Mid-Atlantic region late this weekend into early next week with winds shifting northeasterly winds by Sunday 10 to 15 knots.

Ice formation and rapid growth is likely to continue or accelerate with the upcoming very cold weather late this week through next week. The nearshore ice is not fastened to the shoreline, so it is possible that this ice in the central and eastern basins gets pushed around slightly into open water areas in the offshore winds.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...Winter Weather Advisory from 10 AM this morning to 7 AM EST Thursday for PAZ001>003. MARINE...None.