textproduct: Cleveland

WHAT HAS CHANGED

Increased POP's in/near the primary snowbelt of NE OH and NW PA this evening into the predawn hours of Saturday morning in order to account for an expected period of lake-enhanced precip, first in the form of a rain/snow mix, but changing quickly to all snow via CAA at the surface and aloft. The lake-enhanced snow will then transition to pure lake-effect snow before precip ends in response to eventual and significant dry air advection at the surface and aloft, and accompanied by W'erly mean low-level flow. Total snow amounts from this activity should be a coating to 3". Greatest amounts are expected in the higher terrain of NW PA.

KEY MESSAGES

1) Strong winds are expected today which may result in downed trees and power lines. Widespread power outages remain possible today. Scattered rain/snow showers are also possible, especially across northern counties.

2) Another robust low pressure system will impact the region on Sunday and Monday, brining another round of strong winds. This system will have more widespread precipitation.

DISCUSSION

KEY MESSAGE #1: Confidence is high that a high wind event will occur today across the area, likely resulting in areas of downed trees and power lines and the potential for widespread power outages. Hi- res model guidance is persistent in a strong 850mb LLJ of 50-60 knots pushing across the area. Winds will quickly ramp up today as the mixing layer deepens and lapse rates steepen. Current models continue to suggest mixing heights increasing to almost 850mb this afternoon, leaving a direct path for this LLJ to mix to the surface. Sustained winds today will reach 25 to 35 mph, with gusts of 50 to 60 mph likely. The winds gusts will peak this afternoon. Isolated 'power showers' are also possible as any shower that develops will aid in mixing these strong winds to the surface. With that being said, much of the shower potential should be focused across the northern counties and Lake Erie, although cannot rule out a stray shower further south. To account for these hazardous conditions, a High Wind Warning remains in effect for the entire area today. Additional elevated winds across far NEOH and NWPA tonight have warranted an extension in the headline tonight with those counties now expiring at 2AM EDT. Winds will return to 5 to 15 mph by Saturday morning, lingering from the northwest.

KEY MESSAGE #2: On Sunday, a deepening low pressure system will begin to move northeast into the Great Lakes region, moving a warm front north early Sunday. This system will become centered over the region on Monday, moving a strong cold front east. Given the very strong pressure gradient that is expected, confidence continues to increase in another round of widespread, strong winds.

Winds will begin to ramp up Sunday afternoon behind the warm front as temperatures climb into the 60s. Along the warm front, scattered rain/snow showers are possible, although little to no accumulation is expected. Winds will gradually back starting Sunday night as a strong cold front is expected to begin to push east. A strong LLJ of 50 to 60 knots will push across the area, only enhancing surface winds. Current forecast suggests sustained winds of 25-35 mph with peak gusts of 40-50 mph possible Monday.

In addition, ahead and along this cold front, more widespread rain showers are expected and given the strong dynamic set-up, cannot rule out a few rumbles of thunder. These widespread showers will progress east throughout the day on Monday, gradually transitioning back to snow Monday afternoon as a CAA regime sets in. This means that high temperatures for the day will likely occur Monday morning, reaching into the 50s to 60s before quickly falling into the 20s overnight. Initial snowfall accumulations should remain minimal given the warmer antecedent conditions, but as showers approach eastern counties Monday evening, CAA coupled with a setting sun may result in snowfall accumulations of 1-3 inches.

AVIATION /12Z Friday THROUGH Tuesday/

A mix of snow and rain showers will be more widespread than previously thought over the next 2 to 3 hours this morning as a warm front works across the region bringing a band of precip. Most of this will be light, but brief drops to MVFR/IFR are possible anywhere. The best chance for IFR continues to be at KERI. Once this band exits the region, mainly dry conditions are expected today until scattered snow showers in the cold air advection this evening into tonight, mainly in NE Ohio and NW PA impacting KCLE and KERI.

The main issue today continues to be the high winds. Expect winds to rapidly increase this morning, with SW winds of 25-35 knots gusting to 45 knots by 16Z at most terminals. Winds will turn W behind the trailing cold front this afternoon, with gusts over 50 knots likely, especially in NW Ohio and near the lakeshore. W winds will gradually diminish tonight.

Outlook...Non-VFR likely to return in rain/snow showers Saturday night into Sunday. Non-VFR may linger in scattered rain/snow showers on Monday with lake effect snow possible Monday night into Tuesday.

MARINE

Strong low pressure passing through the central Great Lakes today will bring solid Gale conditions to all of Lake Erie. S to SW winds will increase to 30-35 knots this morning before further increasing to 30-40 knots this afternoon while becoming WSW. Gusts to 50 knots are still expected this afternoon. This will build wave heights to 10-13 feet in the central and eastern basins and 6-9 feet in the western basin. Gale Warnings remain in effect through 08Z Saturday for the entire lake, with a Low Water Advisory for the western basin as the WSW winds drop water levels 1-2 feet below low water datum.

The winds will slowly diminish tonight into Saturday morning and will become light and variable during the day Saturday as high pressure builds across the region. E winds will increase to 15-20 knots Saturday night, becoming SE and further increasing to 20-30 knots by late Sunday. Winds will then turn S Sunday night and eventually WSW Monday afternoon while further increasing to 30-40 knots as another strong low crosses the region, so Gales look likely again Sunday night into Monday. W winds will gradually diminish Monday night into Tuesday.

CLE WATCHES/WARNINGS/ADVISORIES

OH...High Wind Warning until 8 PM EDT this evening for OHZ003- 006>010-017>023-027>033-036>038-047. High Wind Warning until 2 AM EDT Saturday for OHZ011>014-089. PA...High Wind Warning until 2 AM EDT Saturday for PAZ001>003. MARINE...Gale Warning until 4 AM EDT Saturday for LEZ142>147-162>167. Low Water Advisory until 4 AM EDT Saturday for LEZ142>144- 162>164. Gale Warning until 4 AM EDT Saturday for LEZ148-149-168-169.