Area Forecast Discussion
Issued by NWS Cleveland, OH

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755 FXUS61 KCLE 182039 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 339 PM EST Mon Feb 18 2019 .SYNOPSIS... High pressure over the northern Plains will build southeast into the Great Lakes region tonight and Tuesday. Low pressure over the southern Plains will move northeast into the central Great Lakes by Wednesday night, eventually moving across southern Quebec Thursday. High pressure will build back into the region for Friday. && .NEAR TERM /THROUGH TUESDAY/... Trough lingering across northern Ohio through the morning but was pulling east this afternoon and taking moisture with it. Still, many area reporting light snow early this afternoon but that should become more insignificant into late afternoon and evening as drier air continues to move in from the north. Stratus had moved out of northwest Ohio around noon but increased sun and low level instability caused convective cu to develop. For the evening expect clouds to continue to decrease as high pressure and drier air move in and low level convective cu dissipates. Tuesday will continue with a partly cloudy forecast with broad high pressure across the area. Tuesday night is beginning to look interesting as moisture lifts north into the area ahead of low pressure moving north out of the lower Mississippi Valley. Strong warm advection will develop through the TN Vly and central Plains late Tuesday, eventually developing across the local area mainly after midnight into Wednesday transporting deep moisture into the area from the Gulf Coast. Models bring this moisture in mainly after midnight Tuesday night. Expect snow to move in from the south/southwest after midnight reaching near a TOL-YNG line by 12Z. Looking at BUFKIT, precip will be mostly snow but towards dawn Wednesday would expect a mix with freezing rain far south cutting snow accums as warmer air moves in aloft. For now will have 1 to 3 inches far south from Marion to Knox counties with around an inch FDY to MFD. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Precip will be overspreading the region from the southwest on Wednesday as low pressure approaches the western Great Lakes from the southern Plains. An area of strong 925-700mb ascent will work northeast along the Ohio valley on the edge of a strong 50-70kt low level jet. Upper divergence will be increasing across the Great Lakes region as a strengthening upper jet works northeast into the region, at the entrance region of a very strong zonal upper jet moving east over the northern Atlantic. While the local area will be in between the core of these two forcing mechanisms, there will be enough mid/upper support for vertical ascent to warrant high likely/categorical pops on Wednesday, although precipitation amounts will be higher to the northwest and southeast of the forecast area. Precipitation type will be somewhat of a challenge until the attendant surface warm front lifts north through the area by late Wednesday afternoon, however a fairly isothermal sounding warming uniformly from the surface to the mid levels suggests a fairly sharp transition from snow to rain, although enough lag in surface temps may suggest a low impact freezing rain threat for only a couple of hours from south to north. Rain should be the predominant p-type after 18Z Wednesday. The surface low will be near Lake Michigan by 00Z with a lagging cold front/occlusion/trough lifting northeast through the area from 03Z Thursday through 12Z. A large area of high pressure will then build east across the Great Lakes region Thursday through Friday, providing dry conditions and temps a few degrees above normal. Highs will generally be in the low 40s through the period. Low will be in the low 30s Wednesday night, dropping into the low to mid 20s Thursday night. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... If you are paying attention to the large scale synoptic pattern, it will appear to be looping on repeat by the time we get to the weekend. This will be the third iteration in a weeks time of digging western CONUS trough, downstream eastern CONUS ridge amplification, accelerating upper jet rounding the trough and ejecting towards the Great Lakes, surface cyclogenesis across the southern Plains lifting into the Great Lakes, and low level return flow lifting moisture into the region on the heels of a strengthening low level jet. What does this all mean? Another area of precip is expected to lift through the region this weekend. Ridging will move from the Great Lakes into New England, keeping conditions dry Friday night, but precip chances increase Saturday, with the best shot at precip of Saturday night. Some lingering precip is possible Sunday as the low lifts northeast out of the Great Lakes, but will generally be drying by late Sunday night into Monday. The difference with this system is that we will start out with warmer temperatures, with the onset of precip looking to be mainly rain. Temps will rise into the upper 40s to mid 50s Saturday and Sunday. Cooler air returns by Monday with highs in the upper 30s. && .AVIATION /18Z Monday THROUGH Saturday/... Widespread MVFR Cigs to start this afternoon with light snow and fog affecting most terminals dropping conditions to IFR at times. satellite shows drier air dropping into the area from the north which should tend to dry up the snow and lift CIGS. Will start TOL terminal at VFR. Elsewhere hesitate to bring clearing into the north shore as usually clouds hold tight to the coastline through mid day before drier air overcomes coastal lift so have shaded toward a more pessimistic MVFR afternoon. There is a chance however that clearing does work in so will continue to monitor for a more widespread VFR developing. Overnight into Tuesday trend will be to VFR as high pressure builds in. OUTLOOK...Non-VFR possible Tuesday night into Thursday morning. && .MARINE... Quiet conditions expected on a mostly ice covered lake through the middle of the week as high pressure moves across the region. A low will pass northwest of the lake Wednesday night, with a warm front lifting north and winds becoming southerly ahead of this system on Wednesday. A cold front will quickly follow Wednesday night, with winds becoming west southwest behind the front, generally 15-20 kts. Winds will subside on Thursday as another high moves across the region, with light and variable winds expected into the weekend. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...Greenawalt LONG TERM...Greenawalt AVIATION...TK MARINE...Greenawalt is the U.S. government's official web portal to all federal, state and local government web resources and services.