textproduct: Cleveland

WHAT HAS CHANGED

There is high forecast confidence that a very cold weather outbreak is coming to the Great Lakes region later this weekend into next week. Confidence is also increasing for the potential of impactful lake effect snow off of Lake Erie early next week with a west to southwest wind. Initially the lake effect will focus the heaviest snow towards southwestern New York, but there is increasing potential for impactful snow to move into Northeast OH and Northwest PA for a time period Monday into Tuesday.

KEY MESSAGES

1) A low pressure system will track across the Upper Great Lakes and bring the chance for scattered light snow showers today through Saturday. There will be a brief period of slightly milder temperatures today through early Saturday before much colder weather returns.

2) A prolonged period of frigid weather will arrive Saturday night through Tuesday night. High temperatures will be in the 10s and overnight low temperatures in the single digits to slightly below Zero. The coldest weather and potential for dangerous wind chills is expected Monday through Tuesday.

3) An Arctic cold front may bring light snow showers to the area early next week. Impactful lake effect snow is possible late Sunday night through Tuesday night for far Northeast Ohio and Northwest Pennsylvania.

DISCUSSION

KEY MESSAGE 1... We will have a brief period of milder temperature today through early Saturday before the weather becomes frigid for several days. The upper level weather pattern has been this persistent trough over the Great Lakes and Ohio Valley region. This upper level trough will become stronger and deep as we head into this weekend through next week. A low pressure system will track across the Upper Great Lakes today through Saturday. Ahead of this low pressure system, there will be a brief push of milder weather with high temperatures today and early Saturday reaching near or slightly above the freezing mark. Today and early tomorrow will be the warmest weather we have in the forecast for a good while. This low pressure system today into the weekend will bring a chance for scattered light snow shower across the area. Any snowfall amounts today through tomorrow will be very light up to an inch.

KEY MESSAGE 2... Ready or not...some frigid weather is coming our way later this weekend into early next week. There is high forecast confidence for this cold weather outbreak. An Arctic front will move through the Great Lakes and Ohio Valley late Saturday, ushering in an Arctic airmass through Tuesday. The coldest temperatures and potential for dangerous wind chills will be Monday through Tuesday. High temperatures will only be in the 10s Monday and Tuesday. There may be some locations in Northeast Ohio and Northwest Pennsylvania that may not get out of the single digits for high temperatures. Overnight low temperatures will be in the single digits Monday and Tuesday night. The coldest night will likely be Monday night with some locations going below Zero for low temps. Dangerous wind chills are likely Monday through Tuesday with values potentially between -10F and -20F. A cold weather advisory may be needed Monday into Tuesday.

KEY MESSAGE 3... Impactful lake effect snow will likely develop as Arctic airmass moves over the Great Lakes late Sunday night through Tuesday night. Initially this potential lake effect snow will be towards southwestern New York with a southwesterly wind flow off Lake Erie. This low level flow will become more westerly Monday into Tuesday which will steer the potential lake effect snow into far Northeast Ohio and Northwest Pennsylvania. There is increasing forecast confidence for heavy lake effect snow to impact these areas early next week.

AVIATION /06Z Friday THROUGH Tuesday/

Terminals across the region have become mostly VFR with ceilings around 030-035 with a few pockets of MVFR ceilings as a cloud deck moves through. Conditions will become widespread MVFR by 13-16Z 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 around 21-01Z this evening as the snow showers taper off from west to east. Ceilings will remain mainly MVFR through the end of the TAF period.

Winds have begun to shift to be out of the west to southwest at 5-10 knots all will back to be out of the south by around 12Z. Around that timeframe, winds will start to gust to 20-25 knots and will continue through much of the TAF period until after 00Z tonight.

Outlook...Non-VFR likely in snow showers through Saturday. Non-VFR within lake effect snow showers likely across northeastern Ohio and northwestern Pennsylvania Sunday night through Monday.

MARINE

An active marine period is in store as multiple systems move through the Great Lakes into next week. Ice continues to grow across the western basin of Lake Erie, thus will largely be focusing on the central and eastern basins in this discussion.

Elevated south to southwest winds of 20 to 25 knots will return by this afternoon, with a brief lull expected late this evening and overnight as winds diminish to around 15 knots. Small Craft Advisories will need to be re-issued once the current headlines expire tonight as west to southwest winds of 20 to 25 knots arrive on Saturday, increasing to 25 to 30 knots by late Sunday into Monday. Confidence is increasing for Gales on Monday into Tuesday as west to southwest winds increase further into the 30 to 35 knot range. In addition, an arctic airmass will arrive across the Great Lakes on Monday, increasing the risk for heavy freezing spray during this timeframe. Winds will subside slightly to 20 to 25 knots and favor a southwest direction by Wednesday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...None. PA...None. MARINE...Small Craft Advisory until 10 PM EST this evening for LEZ146- 147. Small Craft Advisory until 1 AM EST Saturday for LEZ148-149.