888 FXUS61 KCLE 301644 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 1144 AM EST Mon Dec 30 2019 .SYNOPSIS... Developing low pressure over west-central Ohio early this morning deepens as it moves northward to near the far-eastern part of Michigan's Upper Peninsula by this early afternoon, allowing the occluded front to sweep northeastward through our local area this morning. The low will then drift eastward and become centered over southwestern Quebec by the end of Tuesday. A secondary cold front accompanying this low should sweep eastward through our local area Tuesday afternoon and evening. A ridge of high pressure will build over the area on Wednesday and then slide off the east coast on Thursday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Update...Winds have dropped below advisory levels late this morning and while there still could be a few rogue gusts to 40kts this afternoon, believe for the most part we should remain below. Therefore, will drop the wind advisory. Still however, it will be a windy afternoon and evening. No other big changes through the afternoon. PREVIOUS DISCUSSION...A surface low developing over far-western OH early this morning will deepen overall as it moves generally northward and becomes centered near the eastern shore of Lake Superior by nightfall. Aloft, a mid- to upper- level low will move northeastward from southwestern MN and become vertically- stacked with the surface low by sunset. Multiple shortwave troughs will revolve around this mid- to upper-level low. Back at the surface, an occluded front will sweep northeastward through our CWA through about 8 AM EST this morning. Lift along the occluded front combined with warm air advection, isentropic lift, and impressive moisture transport from the Gulf of Mexico ahead of the front will result in periods of steady to heavy rain. In addition, a line of heavy rain showers is expected to continue accompanying this front and will likely produce brief gusts up to 50 mph as precip transports stronger winds aloft to the surface. These 50 mph gusts are most likely to occur along and west of I-71, where rapid synoptic-scale pressure rises are expected to boost winds. Issued a Wind Advisory through 1 PM this afternoon to account for these gusts. Once the occluded front passes, a pronounced dry slot will overspread our CWA through the rest of the day and result in much lighter and more sporadic rain showers. In addition, mechanical mixing of the boundary layer amidst cold air advection behind the occluded front and a tightening pressure gradient will allow southwesterly surface winds to gust up to 35 to 45 mph. Will continue to evaluate whether the Wind Advisory requires spatial and/or temporal expansion. High temperatures will reach the 50's to perhaps 60 degrees early this morning, prior to the occluded frontal passage. Once the front passes by, temperatures will begin to fall and should reach the upper 30's or lower 40's by sunset. Tonight, the vertically-stacked low will meander near eastern Lake Superior and its cyclonic circulation will continue affecting our CWA as multiple shortwave troughs continue to revolve around the low. As low temperatures settle into the lower 30's, scattered rain showers will change to snow showers. Any snow accumulations should be a half inch or less by daybreak. On Tuesday, the vertically-stacked low will move eastward toward southwestern Quebec and allow a secondary cold front to sweep eastward through our CWA during the afternoon and evening. In addition, two potent shortwave troughs revolving around the low should traverse our CWA from west to east during the morning through early evening. Scattered snow showers, some of which may be heavy, are expected to accompany the front and shortwave troughs since there is potential for a deep dendritic snow growth zone to permit relatively-efficient snow production within the overlying cloud cover. In addition, the airmass over Lake Erie is expected to become cold enough for the development of lake enhanced snows. A southwesterly low-level flow should direct these lake enhanced snows northeast of Lake Erie Tuesday morning, but as the flow veers to westerly Tuesday afternoon and early evening, the lake enhanced snows should shift southward into our snowbelt counties and may also briefly affect areas as far west as the immediate Cleveland metro area as well as Lorain and Erie Counties in OH. Snow accumulations on Tuesday are expected to average 1 to 3 inches in northern OH and 2 to 4 inches in northwest PA. The greatest of these snow accumulations will likely occur in the snowbelt. A Winter Weather Advisory may be needed for at least parts of our CWA and will let future shifts reevaluate this possibility. Tuesday afternoon's highs will likely reach the low to mid 30's. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... A weakening, vertically-stacked low over the northern Great Lakes region will extend a cold front across the area on Tuesday afternoon. The front will be departing the region on Tuesday night, but snow should be ongoing for much of the eastern half of the forecast area. The main snow concern for Tuesday night into Wednesday will be the lake enhancement/effect for the NE OH and NW PA Snow Belt. The fetch over the lake becomes more westerly will would be favorable for the northern part of the snow belt and depending upon help from upstream lakes, there is the potential for some decent amounts of snow accumulation by Wednesday afternoon. A ridge of high pressure enters from the southwest for the second half of the short term forecast period. Flow will shift more to the southwest and send any lake effect into NY and beyond while the region dries out. Warm air advection entering the region for Thursday as a warm front approaches from the southwest will allow for temperatures to surge well above normal. && .LONG TERM /THURSDAY THROUGH SUNDAY/... The long term forecast period appears unsettled as a low pressure system enters from the southwest for the weekend. The area some inconsistencies in the extend guidance on the strength of the low, all of the solutions show rain for Friday changing over to rain/snow for weekend as cooler air returns. The final cold front appears to arrive by Sunday and any precipitation would then change over completely to snow by Sunday night. && .AVIATION /12Z Monday THROUGH Friday/... A deepening surface low centered near Saginaw Bay, MI will continue moving northward and become centered near eastern Lake Superior by 00Z/Tue. An occluded front just east of KCLE and KCAK will continue moving eastward and likely exit our area by 14Z/Mon. A line of heavy rain showers along this front may continue to produce brief gusts up to 40 to 50 knots. The aforementioned low should then meander in vicinity of eastern Lake Superior and weaken gradually through 12Z/Tue. Southeasterly surface winds will veer to southwesterly with the passage of the occluded front. These southwesterly surface winds are expected to gust as high as 25 to 35 knots, especially through this evening. In addition, rain showers will become isolated in coverage following the front. Ceilings will trend VFR to MVFR through the TAF period, but brief periods of IFR ceilings cannot be ruled-out. In addition, visibility is expected to trend VFR through 03Z/Tue. Thereafter, rain showers should mix with and then change to snow and these snow showers should become scattered as colder air overspreads the area. MVFR to IFR visibility may accompany these snow showers. .OUTLOOK...Non-VFR are expected in snow showers on Tuesday. By Wednesday, non-VFR should be confined to the snowbelt due to lake effect snow. Non-VFR are possible in scattered showers Thursday evening and Friday. && .MARINE... The lake will be fairly active to begin the week. An area of low pressure over Northwest Ohio will move north along an occluded front into the Great Lakes region and deepen. As the low passes Lake Erie to the northwest this morning, a brief window of strong southwest winds is expected over the western half of the lake. Winds will be close to gale force, but will keep the forecast to 30 kts. As the low continues north, elevated southwest winds will persist over the lake today and waves will increase across the basin. This low will then extend a cold front across the lake on Tuesday, bringing another window of stronger west winds to 30 knots over the basin. Waves will build along the nearshore waters on Tuesday and Tuesday night and have extended the Small Craft Advisory through 4 AM Wednesday for the western basin and 4 PM Wednesday for the central and eastern basin as the waves will build into the nearshore waters and persist for several hours after the winds begin to diminish. A ridge of high pressure enters from the southwest for the middle of the week and winds will shift around to the southwest and greatly diminish, allowing for more benign weather conditions for Thursday. Low pressure enters from the southwest for Friday and will bring strong winds to the lake for the weekend. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Low Water Advisory until 4 PM EST this afternoon for LEZ142>144-162>164. Small Craft Advisory until 4 PM EST Wednesday for LEZ144>149. Small Craft Advisory until 4 AM EST Wednesday for LEZ142-143. && $$ SYNOPSIS...Jaszka NEAR TERM...Jaszka/TK SHORT TERM...Sefcovic LONG TERM...Sefcovic AVIATION...Jaszka MARINE...Sefcovic