Area Forecast Discussion
Issued by NWS Cleveland, OH

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874 FXUS61 KCLE 210235 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 935 PM EST Tue Feb 20 2018 .SYNOPSIS... A cold front will move east across the area late tonight through Wednesday. As the front settles just south of the area, low pressure will track northeast along the front Wednesday night through Thursday. The front will lift back north through the area as a warm front Thursday night into Friday as another low pressure system develops and tracks northeast into the Great Lakes. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... No significant changes for the 930 update. Low pressure now centered over Northern Lake Huron with the leading edge of the cold front into NW OH. Wave entering Mid Mississippi Valley will slow the progression of the front. Original discussion... Rain chances are taking a pause across the area late this afternoon, as much of the early afternoon precip has lifted northeast out of the forecast area. Rain chances will increase from the west later this evening through the overnight as a cold front pushes towards the area. Kept a mention of slight chance thunder in the grids through 06Z, although instability and forcing will be diminishing, and upstream lightning trends have greatly diminished. The front will push through the area, with rain continuing behind the surface frontal passage for a period of time tonight through Wednesday. Only minor changes to pops and hourly temperature trends from the previous forecast. Will keep the Flood Watch up for Lucas County for this forecast update, however flooding risk has greatly diminished, with additional rainfall amounts tonight of a half to three quarters of an inch. The heaviest rainfall will occur along and just ahead of the front, but only light to occasionally moderate rain is expected behind the front. Main forecast challenge for this period is Wednesday night in the wake of the surface cold front. Surface temperatures are expected to fall to around 30 degrees across much of the area, with some upper 20s possible across the northern part of the area. A wave of low pressure will track northeast along the front through the Ohio valley, with precip overspreading the area from southwest to northeast, and greatest precip chances across the southeast part of the forecast area. P-type issues and impacts will remain fairly tricky, with rain expected south of the surface boundary where temps will remain above freezing, a thin line of mixed precipitation just northwest of the front, and then light snow further north, if any precip makes it that far north. This thin transition zone is the main concern, with a period of freezing rain and sleet possible. Forecast soundings support freezing rain, but north/northeast flow will usher in fairly dry air into this transition zone, so expecting some wet bulbing to occur as the precip saturates the column. This may support more of a partial melting and more of a sleet/snow concern vs. freezing rain. Compounding the impact uncertainty, ground temperatures will be fairly warm where freezing rain potential exists, after record high temperatures today. Any freezing rain impacts may be limited to overpasses and elevated surfaces at this point, with other road surface impacts being fairly limited if existing at all. Any snow/sleet accumulations should be less than an inch through early Thursday morning. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Abundant moisture will continue to stream northeast into Ohio on Thursday as strong upper level high pressure sits off the Carolinas coastline while a broad upper trough dominates the Great Basin. Cold air will begin to slowly settle south with snow possible generally across the northern half of the area and a wintry precipitation mix across the southern half of the area. The best chance for this wintry precipitation mix will occur early Thursday morning through around noon on Thursday. We will continue to fine tune details leading up to Thursday morning as the GFS is a bit faster than the ECMWF with precipitation timing. Either way...expect generally an inch or less of snow across the northern portion of the area and only minor accumulations of freezing rain and/or sleet across the southern portion. After the brief cool down on Thursday...a warming trend is expected Friday into Saturday with temperatures generally in the mid 40s to mid 50s as 850 mb temperatures rebound to nearly 10 C. A few rounds of rain are expected to impact the area Friday and Saturday...with subtle timing difference between the GFS and ECMWF. Either way there will be at least a chance of precipitation from Friday morning through Saturday. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Precip will be ongoing at the start of the period as the last in a long series of low pressure systems impacts the area. The surface low will move northeast across the central Great Lakes Saturday night into Sunday forcing a front across the local area. The usual difference is the track and timing of the main features exist but this will have little impact on the practical weather. It`s going to rain everywhere and some of the rain...especially at the southern end of the area could be heavy. The rain should end from west to east Sunday afternoon and evening. High pressure will move over the region for the start of the new workweek and Monday and Tuesday but should be dry. Temperatures will be cooling during the period but will still be a little above normal on Tuesday. && .AVIATION /00Z Wednesday THROUGH Sunday/... Rainshowers will move over Western half of forecast area overnight ahead of approaching cold front. Enough shear for isolated TSRA possible NW OH. LLWS possible early this evening. Surface winds have decoupled and 925mb winds 20040-45kt. The 925 MB winds will increase to 50kt overnight but expect surface winds to pick up by then. OUTLOOK...Non-VFR Wed morning ins -shra. More Non- VFR Fri and Sat with the next front. && .MARINE... Brisk south to southwest winds will continue tonight ahead of a slow moving cold front. The front will cross Lake Erie Wednesday morning and winds will shift to northwest and north. Wind speeds should diminish relatively quickly within a few hours of frontal passage. Winds will veer all the way to ENE as high pressure slides across eastern Canada into the weekend. A cold front will cross the lake on Sunday and winds will become southwest and a more seasonable and drier air mass will spread across the lake early next week. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Flood Watch through Wednesday afternoon for OHZ003. PA...None. MARINE...None. && $$ SYNOPSIS...Greenawalt NEAR TERM...DJB/Greenawalt SHORT TERM...KEC/Riley LONG TERM...Kubina AVIATION...DJB MARINE...Riley is the U.S. government's official web portal to all federal, state and local government web resources and services.