textproduct: Cleveland

WHAT HAS CHANGED

Increased the snow forecast for today's lake-effect snow, and we're now looking at an additional 1-3 inches of snow across the snowbelt of Northeast Ohio and Northwest Pennsylvania. Also increased the snow forecast for Tuesday's clipper. Generally expecting most of the area to get at least a dusting of snow, with an additional 1-3 inches of snow across the snowbelt. Finally, the Extreme Cold Watch was upgraded to an Extreme Cold Warning, with wind chills forecast to reach -25 across much of the area tonight into Tuesday morning.

KEY MESSAGES

1) Lake-effect snow continues across Northeast Ohio and Northwest Pennsylvania, causing poor road conditions to linger through this evening.

2) Dangerous wind chills down to -25 F are expected to bring significant cold exposure risks to the entire area tonight into Tuesday morning.

3) Light snow is expected areawide on Tuesday, with lake- enhanced snow producing light snow accumulations across Northeast Ohio and Northwest Pennsylvania. This may produce minor travel impacts.

4) Prolonged cold is expected through the weekend creating elevated risks for cold exposure and damage to infrastructure.

DISCUSSION

KEY MESSAGE 1... Low- level moisture wrapping around the departing 850mb low continues to linger across the area. Cold air over lake effect has produced minor lake-induced CAPE, which along with orographic lift, has produced light, accumulating snowfall across the primary snowbelt of Northeast Ohio and Northwest Pennsylvania early this morning. Area cameras and traffic speed information indicates that travel impacts remain due to snow- covered roads (including major highways) from yesterday's major winter storm, especially in the Cleveland-Akron metro area.

Upstream, and upper-level trough resides over the northern Great Lakes and Upper Midwest. This trough will move southeast across the Great Lakes, further producing lift and deeper moisture up 700mb. 850mb temperatures should further cool down this morning to around -18 C, which as the upper-level trough approaches, should re-intensify the lake-effect snow across the primary snowbelt. Despite Lake Erie being nearly ice-covered (latest analysis has Lake Erie at 92% ice-covered), additional moisture and warmth can be provided through thin ice, and cracks in the ice. Additional snow accumulations of around 1 to 3 inches are expected in the primary snowbelt with localized higher amounts of 3 to 4 inches possible in eastern Cuyahoga, southern Lake, northern Geauga, and Erie, PA south of I-90. Where it snows, expect minor travel impacts to persist through this evening.

As a result, the Winter Storm Warning has been downgraded to a Winter Weather Advisory and extended through 4 PM today to better reflect the ongoing but lower-end travel impacts from lingering snow cover and light lake effect snowfall.

KEY MESSAGE 2... The upper-level trough departs to the east, and an arctic airmass associated with surface high pressure centered over Texas will extend northeastward towards the lower Great Lakes region. As the ridge builds in, should see an area of clearing skies, and aided by a deep snowpack, should see temperatures plummet below zero areawide. The temperature forecast trended lower with this forecast package, especially in central and east-central Ohio where low temperatures could dip to -5 or lower. Breezy southwest winds develop early Tuesday morning behind the departing surface ridge, which when combined with the cold air temperatures will produce dangerous wind chills down to -25. The Extreme Cold Watch was upgraded to an Extreme Cold Warning for the entire area from 7 PM this evening through 11 AM Tuesday morning.

KEY MESSAGE 3... A clipper system swings southeast across the Great Lakes on Tuesday with sufficient cold air and moisture depth for brief, light snow across the area Tuesday morning. Breezy southwest winds Tuesday morning may result in patchy blowing or drifting snow, especially west of I-71 where wind gusts of 30-35 mph will be possible. This will transition to lake effect snow showers for the primary snowbelt of Northeast Ohio and Northwest Pennsylvania where an additional 1 to 3 inches of snow and minor travel impacts are expected.

KEY MESSAGE 4... An upper-level trough remains over much of the eastern CONUS through the end of the week, with stubborn anomalously cold temperatures across the Great Lakes region through the weekend. The recent snow storm has produced a deep snowpack areawide, which should further enhance cold temperatures across the area. Air temperatures at or below zero will be common through Saturday with minimum wind chill values ranging between -10 and -25, increasing the risk of frostbite or hypothermia. Additional Cold Weather Advisories or Extreme Cold Warnings are likely.

Infrastructure impacts from cold air temperatures tend to increase for longer duration events, especially when the daily average temperature dips below 16 degrees (this is a local criteria) for multiple days. This results in increased likelihood of burst frozen pipes, dead car batteries, power outages, increased chances for carbon monoxide poisoning (from improper use of secondary sources of heat) and structure fires.

Additionally, we will likely start to see ice develop and thicken on area rivers.

AVIATION /12Z Monday THROUGH Friday/

Northwest and north central Ohio terminals (KTOL, KFDY, and KMFD) will see improving conditions by mid to late morning as drier air works into the region and gradually ends the lingering lake-effect snow. However, the snow showers will be stubborn much of the day across the rest of the area keeping conditions MVFR to occasionally IFR at KCLE, KCAK, KYNG, and KERI. Put in long periods of MVFR snow showers at these sites. There will be breaks, but they are tough to time since the snow will be frequent. Visibilities and/or cigs could drop to IFR at any time at these sites in the heavier snow showers. High pressure will finally dry out all terminals by tonight with cigs improving to VFR, but another clipper system and associated cold front rapidly approaching by Tuesday morning will start to bring snow showers and decreasing cigs/vis back to northern sites.

NW winds of 5-10 knots this morning will gradually back more W today and increase to 10-15 knots. Winds will continue to back to SW tonight and further increase to 15-20 knots with gusts of 20-30 knots by Tuesday morning.

Outlook...Additional periods of snow with non-VFR are likely through Friday. Greatest chances exist in NE OH and NW PA, where periodic lake-effect snow downwind of mainly ice-covered Lake Erie should occur.

MARINE

NW winds early this morning will gradually shift to WSW by this evening with speeds increasing to 10-20 knots. SW winds will further increase to 20-30 knots late tonight and Tuesday ahead of a clipper system and associated cold front dropping through the Great Lakes. Winds will turn WNW behind the front Tuesday evening and Tuesday night, with speeds decreasing to 10-15 knots. Another clipper approaching the region will back winds on the lake to SW at 10-20 knots Wednesday before turning NW and decreasing to 10-15 knots behind the associated cold front Wednesday night and Thursday. NW winds of 10-15 knots will then continue through Friday.

Lake Erie is mostly ice covered, and the ice will continue to thicken this week as a deep arctic airmass remains entrenched across the region. The shifting wind directions may also cause the ice to shift, especially during the periods of stronger SW winds tonight and Tuesday and again Wednesday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Extreme Cold Warning from 7 PM this evening to 11 AM EST Tuesday for OHZ003-006>014-017>023-027>033-036>038-047- 089. Winter Weather Advisory until 4 PM EST this afternoon for OHZ010>014-020>023-089. PA...Extreme Cold Warning from 7 PM this evening to 11 AM EST Tuesday for PAZ001>003. Winter Weather Advisory until 4 PM EST this afternoon for PAZ001>003. MARINE...None.