textproduct: Cleveland

WHAT HAS CHANGED

Confidence in strong southwesterly winds tomorrow has increased enough to upgrade the entire area to a High Wind Warning from early Friday morning through Friday evening.

KEY MESSAGES

1) Damaging winds may blow down trees and power lines, causing widespread power outages on Friday. Scattered rain/snow showers are also possible.

2) A strong low pressure system moves through the area Sunday into Monday, bringing rain, snow, and windy conditions.

DISCUSSION

KEY MESSAGE #1: Deepening low pressure will glide east across the Lower Great Lakes tonight through Friday. The low will initially lift a warm front across the local area overnight tonight. Light snow showers late tonight will eventually transition to all rain by Friday afternoon behind the warm front. Aloft a strong LLJ characterized by 850mb winds 60-70 knots across western zones and 40-50 knots across eastern zones will move overhead early Friday morning. Latest guidance continues to show mixing heights to almost 850mb which would certainly mix down the strong LLJ to the surface, particularly in any showers. Hi-res models have been persistent in showing a large swath of the forecast area with upwards of 50 kt (58+ mph) wind gusts through Friday along and ahead of a cold front associated with the low pressure system. As such, the High Wind Watch has been upgraded to a High Wind Warning across the entire forecast area through tomorrow evening. Winds will begin to diminish behind the frontal passage tomorrow night.

KEY MESSAGE #2: High pressure briefly returns on Saturday before another low pressure system approaches the region Sunday into early next week. The low will lift a warm front north across the region during the day on Sunday with snow showers transitioning to all rain behind the front. Additionally, highs on Sunday will warm into the mid to upper 60s. Warm weather doesn't last long as the low pushes northeastward and drags a cold front east across the region on Sunday night into Monday. Precipitation will change back over to snow with the frontal passage. Can't rule out another period of breezy conditions early next week with this low pressure system. Current NBM probabilities of wind gusts reaching Wind Advisory criteria (46+ mph) generally range between 40-70% across the forecast area. Will need to keep an eye on this timeframe for any potential wind headlines.

AVIATION /00Z Friday THROUGH Tuesday/

A strong low pressure approaches from the Upper Midwest for Friday. The main concern for the taf period will be very strong winds developing on Friday. Southerly winds will begin to increase between 09-12Z with initial gusts to 30-35 knots, before ramping up considerably with sustained winds of 28-30 knots and gusts of 40-50 knots. Winds will be southerly to start shift to the southwest by early afternoon and then west by late afternoon. Clouds are generally expected to be VFR with the possible exception being at ERI where showers are the most likely on Friday. A quick band of snow may be possible with the warm late Friday morning, followed by rain showers Friday afternoon transitioning back to snow showers later in the afternoon.

Early Friday morning, there is a 2-4 hour window in Northwest Ohio where low level wind sheer could be possible. Surface winds are generally expected to increase concurrent with a strong low level jet aloft and tightening surface pressure gradient ahead of low pressure moving into the Upper Great Lakes, though surface stability could slow down the development of the strongest gusts.

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

Current round of Small Craft Advisories will expire at 4 PM but a Gale Warning is already in effect for Friday and Friday night. Southerly winds increase rapidly on Friday morning with gales beginning between 12-15Z on the western basin and 17-20Z on the eastern basin. Winds could gust as high as 50 knots during this time with winds shifting from southerly to southwesterly with the passage of a cold front during the afternoon. The strong winds are likely to result in low water conditions on the western basin with water levels falling as much as 1-2 feet below low water datum. A Low Water Advisory is already in effect from 8 AM Friday to 4 AM Saturday with the lowest conditions expected Friday evening. With most of the ice gone on Lake Erie, waves of 8-12 feet are possible with the Gale.

While conditions are forecast to rapidly improve on Saturday as high pressure moves east across the region, another strong low pressure system is forecast to track northeast across Lower Michigan and Lake Huron on Monday. This will present another window of very strong winds and gales remain possible. A very strong cold front will move northeast across Lake Erie during the day on Monday. The track and strength of this system will be monitored over the coming days with low water conditions possible again on Monday night.

CLE WATCHES/WARNINGS/ADVISORIES

OH...High Wind Warning from 5 AM to 8 PM EDT Friday for OHZ003- 006>010-017>019-027>030-036-037-047. High Wind Warning from 8 AM to 8 PM EDT Friday for OHZ011>014- 020>023-031>033-038-089. PA...High Wind Warning from 8 AM to 8 PM EDT Friday for PAZ001>003. MARINE...Gale Warning from 8 AM Friday to 4 AM EDT Saturday for LEZ142>147-162>167. Low Water Advisory from 8 AM Friday to 4 AM EDT Saturday for LEZ142>144-162>164. Gale Warning from noon Friday to 4 AM EDT Saturday for LEZ148- 149-168-169.