textproduct: Cleveland

WHAT HAS CHANGED

The ongoing and generally over-performing lake effect snow event will wind down from west to east through this evening. Confidence is increasing in impactful lake effect snow off of Lake Erie early next week with a west to southwest wind. This will focus the heaviest snow across western NY, with some potential for impactful snow to sink into extreme Northeast OH and Northwest PA for a time Monday into early Tuesday.

KEY MESSAGES

1) Heavy lake effect snow will gradually wind down from west to east through the first half of tonight.

2) Low pressure tracking through the northern Great Lakes will bring periodic snow shower chances Friday into Saturday. A brief spell of slightly milder temperatures is expected Friday into early Saturday before colder air returns.

3) A prolonged cold spell with high temperatures in the 10s and low temperatures in the single digits to below 0 is expected Saturday night through Tuesday night, with the coldest overall weather expected Monday into Tuesday. Wind chills will dip below 0, and Cold Weather Advisories may eventually be needed.

4) An Arctic cold front may bring snow showers to the area Monday. Impactful lake effect snow is likely off of Lake Erie late this weekend into early next week, especially into western NY. The greatest potential for impacts across Northwest PA and far Northeast OH appears to be Monday into early Tuesday.

DISCUSSION

KEY MESSAGE 1... As of early this afternoon, moderate to heavy (and very fluffy) lake effect snow continues from northeastern Erie County (OH)/ Lorain County/Medina County points east-northeast across the primary and secondary snowbelts of Northeast OH and Northwest PA. Activity has been intense this morning and early afternoon with snow rates up to 1" per hour and visibility occasionally below 1/4 of a mile observed in the more intense/organized bands. Intensity will remain fairly impressive before activity shuts off fairly quickly from west to east through this evening. In the Cleveland area, fairly quick improvement is expected starting around 4 PM. Synoptic moisture/lift quickly departing as ridging builds from the west gives us confidence in the lake effect losing significant intensity pretty quickly through this evening, with lingering activity through the night focusing across extreme Northeast OH and Northwest PA as winds back to a more southwesterly direction by early Friday.

Additional accumulations from 2 PM and on of 1 to locally 3" are possible where bands persist across Northeast OH, with 2 to locally 6" more possible across Northwest PA. Across the board, the heaviest additional amounts will be in the higher terrain though decent accumulations have been occurring near the lake beneath bands. Will be expiring/dropping LES headlines from west to east as able through this evening and into tonight. Lows tonight will generally be in the 10s and will occur early, with temperatures holding steady or rising slightly overnight as clouds ahead of the next system and southwest winds spread in. Wind chills will remain in the single digits to slightly below 0 this afternoon, warming slightly (but largely staying in the single digits) tonight.

KEY MESSAGE 2... A band of low to mid-level isentropic lift ahead of a flat shortwave will move east-northeast across the forecast area on Friday, bringing potential for a period of light snow or snow showers. The lift will be fairly modest with surface temperatures warming into an upper 20s to mid 30s range, with the greatest potential for snow expected to be across the northern half of the area. Any snow during the day Friday should be fairly low impact with accumulations generally 1" or less. Southerly winds will be a bit brisk on Friday with gusts up to 30 MPH possible during the afternoon.

Potential for scattered snow showers continues Friday night as an initial weak cold front crosses the area. Lows Friday night will not dip much, only into a mid 20s to near 30 range.

A stronger cold front crosses west to east very late Friday night into Saturday, bringing another potential for at least some scattered snow showers. Steepening low-level lapse rates and weak instability ahead of the front may support heftier snow shower or squall potential on Saturday, especially across the eastern half of the area. While overall accumulations are expected to remain light, any heavier snow showers or squalls could bring a brief hazard to travel. Early highs on Saturday are expected to range from the upper 20s to mid 30s (warmest east), with temperatures beginning to fall behind the cold front through the afternoon. A push of wind gusts up to 30 MPH is possible behind the front on Saturday.

KEY MESSAGE 3... The main story Sunday through Tuesday for most of the area will be the cold. Saturday's cold front will usher in an initial colder airmass, with lows Saturday night falling into the upper single digits/lower 10s with wind chills dipping to 0 to -10F. Highs on Sunday will struggle to get above 20, with similar lows Sunday night in the upper single digits/lower 10s with wind chills likely dipping below 0.

A re-enforcing Arctic front will cross late Sunday night or Monday morning, ushering in the coldest air of the winter so far. Highs on Monday will be in the 10s, with some potential for temperatures to fall through the single digits through the afternoon depending on the timing of the front. Gustier winds to over 30 MPH are likely behind the front on Monday. Lows Monday night will be on either side of 0, with increasing confidence in interior locales dipping below 0. Highs on Tuesday will definitely stay well down in the 10s, and it's possible some areas stay in the single digits, particularly across the higher elevations of Northwest PA. One more very cold night Tuesday night, into the single digits and perhaps locally below 0, before a moderating trend begins on Wednesday. A prolonged period of sub-zero wind chills is expected Monday through early Wednesday. The coldest wind chills are likely late Monday through early Tuesday, likely bottoming out at -10 to -20F across the area. That window appear to be the most likely time period for Cold Weather Advisories early next week.

KEY MESSAGE 4... The Arctic cold front that is expected to cross late Sunday night into Monday will likely be accompanied by at least some scattered snow showers. While this doesn't look like much snow for most of the area, the potential for more intense snow showers or squalls isn't always well-advertised well in advance with Arctic fronts and will need to be monitored. Otherwise, the main concern is a window of impactful lake effect snow off of Lake Erie. There may be some lake effect Saturday night into Sunday, though southwest flow should direct that into NY. Locally, the main concern for lake effect will likely be behind the Arctic front Monday into early Tuesday when winds briefly go more westerly. Given the very cold airmass and what will likely still be a partially unfrozen lake, the potential for substantial accumulations exists where the lake effect sets up. This looks like a brief window with winds turning more southwesterly through the day Tuesday, pushing activity back towards NY and out of our area. Those in far Northeast OH and Northwest PA should monitor the forecast due to the potential for a brief window of impactful lake effect early next week.

AVIATION /00Z Friday THROUGH Tuesday/

Lake effect/enhanced snow showers have ended across most of the region this evening with a few straggling showers across far northeastern Ohio and northwestern Pennsylvania. Those locations are still MVFR due to reduced visibility in the snow showers. There is a clearing in the cloud cover as well across much of the region, outside of the locations mentioned above, creating VFR conditions. Another cloud deck is moving in from the west currently, though ceilings have stayed VFR for the most part.

Conditions will become MVFR by 13-15Z as another system moves into the region bringing another round of snow showers. Ceilings and visibilities will drop as a result. There could be some pockets of IFR/LIFR conditions in the stronger snow showers, but generally won't be prolonged. Visibilities will improve towards the end of the TAF period, though ceilings should stay non-VFR.

Winds will be out of the west this evening at 5-10 knots before backing to be out of the south by around 05Z though will still be light. Southerly winds will continue for the TAF period with a period of gusts at 20-25 knots starting around 13-15Z lasting through 00Z Saturday.

Outlook...Non-VFR likely in snow showers on Friday and Saturday. Non-VFR may linger across Northeast Ohio and Northwest Pennsylvania in lake effect snow showers Sunday and Monday.

MARINE

Active period with multiple systems moving across the Great Lakes region will provide a prolonged window of hazardous marine conditions on Lake Erie. Northwest winds 15-20 knots this afternoon will become southwesterly this evening. Southerly to southwesterly winds increase to 20-25 knots again Friday morning/afternoon. Given the offshore component, expect for highest wave heights to occur across the open waters. Small Craft Advisories remain in effect from Vermilion east to Ripley NY through at least Saturday evening. Anticipate for advisories to be extended in time and area Saturday night into early next week as hazardous conditions continue.

Extended the Freezing Spray Warning through this evening as elevated winds and cold air remain across Lake Erie. Warmer temperatures move over the lake tonight through Saturday. Another cold airmass moves over the lake on Sunday. Cold air temperatures in addition to elevated wind speeds will likely lead to another window of heavy freezing spray and additional headlines early next week.

CLE WATCHES/WARNINGS/ADVISORIES

OH...Lake Effect Snow Warning until 7 PM EST this evening for OHZ010>014-020>022-089. Winter Weather Advisory until 7 PM EST this evening for OHZ023- 033. PA...Lake Effect Snow Warning until 1 AM EST Friday for PAZ001>003. MARINE...Heavy Freezing Spray Warning until 7 PM EST this evening for LEZ144>149-164>169. Small Craft Advisory until 7 PM EST Saturday for LEZ145>149.