textproduct: Cleveland

SYNOPSIS

Low pressure will deepen as it tracks east through the Great Lakes Sunday into Monday, extending a strong cold front across the area. A trough will linger behind the front into at least mid- week. Another cold front will sweep southeast through the region late Wednesday into Thursday.

NEAR TERM /THROUGH SUNDAY NIGHT/

The main change with this package is the issuance of a High Wind Watch for much of North and Northwest Ohio, and Northwest Pennsylvania as a strong cold front ushers in westerly wind gusts between 50 and 60 mph on Monday. In addition, the potential for widespread heavy rain appears to be decreasing across our area, with the axis trending further north across Lake Erie and into Michigan.

An active near term period is expected as a strong low pressure system moves east through the Great Lakes Sunday into Monday, rapidly deepening from 1000 mb to near 975mb as it moves northeast from the Missouri Valley to the vicinity of Lake Huron by Monday. This low will lift a warm front north through the area on Sunday morning, increasing temperatures into the 50s to near 60 by the late afternoon and evening. The latest HREF guidance indicates the potential for rainfall totals exceeding 1.0 inch is decreasing, with the highest probabilities becoming confined further north and northwest of the area. The Toledo metro will be close to this gradient and the heavy rain threat will continue to be monitored. Elsewhere, rainfall totals will range between 0.50 and 0.75 inches.

A strong cold front will push east through the area late Sunday night into Monday morning, accompanied by a narrow line of rain showers. The thunder potential is very low with the line, though an isolated lightning strike or two cannot be ruled out at this time. There is some concern that the strong wind field and dry 700 mb air immediately along and behind the cold front and line of rain showers may bring down severe-level wind gusts, though confidence is low, evident via the SPC SWODY2 marginal risk and general lack of instability.

Colder air will filter behind the cold front, with rain transitioning to snow by Monday afternoon and evening. Low-level lapse rates will steepen with mixing heights expected to reach somewhere between 850 and 925 mb. This will result in surface wind gusts to reach between 50 and 60 mph through Monday, with the higher end of gusts most likely found in the High Wind Watch area.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

A strong surface trough will swing southeast through Michigan and into the Eastern Great Lakes late Monday, resulting in a period of lake enhanced snow across Northeast Ohio and Northwest Pennsylvania Monday night. Headlines will be needed in the next couple of forecast iterations given the combination of blowing snow and accumulations of 3 to 7 inches into Tuesday afternoon. Outside of the snowbelt, travel may also be difficult late Monday afternoon and evening with some guidance suggesting the potential for snow showers and/or squalls which could briefly reduce visibilites and coat roadways with snow. Lake enhanced snow will transition to somewhat disorganized lake effect on Tuesday as low-level flow favors a more west to southwest direction ahead of the next system.

Temperatures will remain cold for the short term period with wind chills hovering in the low teens to single digits.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Cold temperatures and periods of snow (both lake effect and clipper) are favored for the long term period as a large upper- level persists across the Eastern CONUS. Highs will range in the 20s, with wind chills in the low teens to single digits favored for much of the period. Model guidance is becoming more aligned in the potential for a clipper system to bring a widespread accumulating snow across the Ohio Valley for New Year's Eve into New Year's Day with increasing probabilities for much of the area to receive at least 1 to 2 inches of snow. Will continue to monitor this potential as exact placement and timing remains uncertain.

High pressure will build from the west by late Friday into Saturday which could result in at least some of the area experiencing temperatures above freezing.

AVIATION /06Z Sunday THROUGH Thursday/

A mix of IFR and LIFR conditions continue across the terminals (except KERI for now) ahead of a warm front. These conditions will continue overnight ahead of the rain with the front. There will be some variation in visibility with some fog/mist in the region; however, the main flight category will be driven by the 300-800 ft ceilings. Rain will enter later this morning and conditions will remain in the IFR/LIFR range. There will be some breaks in the rain and perhaps some breaks in the lowest ceilings. However, have no confidence in precise timing and this will likely need to be refined with later TAF packages. Winds will increase behind the front this evening into tonight and have wind gusts ramping up across the area. If winds are slower to gust at the surface, there may be a LLWS threat during the late afternoon/early evening, but some of this will depend on the rain timing as well.

Outlook...Non-VFR conditions will continue through Monday as rain transitions to snow along and behind a strong cold front. Wind gusts 30 to 50 kts are expected into Monday. Lingering lake effect snow showers will result in additional non-VFR conditions across Northeast Ohio and Northwest Pennsylvania through at least Wednesday.

MARINE

High pressure over the eastern Great Lakes will keep marine conditions calm through tonight with light winds from the east- southeast. Sunday morning, a warm front will lift north across Lake Erie, resulting in winds shifting to become more south-southwesterly and increasing to 15-25 knots into the evening hours. This warm front lifting north will mark a transition to hazardous marine conditions through at least Thursday this week.

As the parent low moves into the region, increased gradient over the area coupled with a strong CAA regime will result in Gale Force winds across all of Lake Erie late Sunday night into Monday morning. These gales will approach Storm Force winds with sustained winds up to 47 knots currently forecast from the southwest. Wind gusts as high as 45-55 knots will also be observed with waves building to 12- 17 feet across the central and eastern basins. Waves will also build to 3-6 feet across the western basin, but given the strong southwest flow the current water level forecast has lake levels falling to 4 feet below low water datum, which is where the model bottoms out. This will pose hazardous conditions along shipping routes and mariners should plan accordingly. To highlight these concerns, there is currently a Gale Watch in effect. A Low Water Advisory will be needed, but opted to allow future shifts to issue this to get hi-res guidance into the forecast.

As a strong cold front pushes east and winds back behind the low on Monday, winds will gradually become west-northwesterly but remain sustained at gales of 35-40 knots through Tuesday afternoon. As the parent low shifts northeast towards Nova Scotia, a lingering surface trough on Tuesday night through Thursday will keep elevated winds of 20-30 knots across much of the lake which will need a Small Craft Advisory on the tale end of the Gale. Overall, strongly recommend refraining from travels on Lake Erie, especially in small crafts.

CLE WATCHES/WARNINGS/ADVISORIES

OH...High Wind Watch from late Sunday night through Monday evening for OHZ003-006>009-017>019-027>030. High Wind Watch from late Sunday night through late Monday night for OHZ010>014-020-021-089. PA...High Wind Watch from late Sunday night through late Monday night for PAZ001-002. MARINE...Gale Watch from late Sunday night through Tuesday evening for LEZ142>144-162>164. Gale Watch from late Sunday night through Tuesday evening for LEZ145>149-165>169.