Area Forecast Discussion
Issued by NWS Cleveland, OH

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000 FXUS61 KCLE 112310 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 610 PM EST Mon Dec 11 2017 .SYNOPSIS... A clipper system will track across the lower lakes tonight sweeping an arctic front across the forecast area early Tuesday morning. Lake effect snow will develop Tuesday and continue through Wednesday. Additional clippers will track across the area Wednesday night and again Friday. && .NEAR TERM /THROUGH WEDNESDAY/... Have issued a Winter Weather Advisories and Lake Effect Snow Warnings that will run through Wednesday evening. A clipper will track across northern Ohio and the east end of the lake tonight into Tuesday morning. A good frontogenetic band will extend light snow into far northeast OH/northwest PA this evening (in addition to the flurries around). But as the low tracks across the state, banding of snow will increase north of the low beginning after midnight, with accumulations of 1 to 3 inches by the end of the morning rush. Amounts will be under an inch outside of north-central, northeast OH and NW PA, but all should see some snow. There will likely be a relative lull between the exiting of the synoptic snow and the organization of lake effect snow Tuesday late morning into the early afternoon. Temperatures will hold fairly steady for a big chunk of the night. But as west and northwest winds pick up after the low/cold front passes temperatures will begin to fall. By late Tuesday afternoon temperatures will be getting into the upper teens. Wind chill values will drop to the single digits. Lake effect snow will be heavy at times, particularly Tuesday night. There is some uncertainty as to how long the significant lake effect will continue and have extended the advisory/warning into Wednesday evening (beyond the previous watch). Set up for the lake effect is really good through Wednesday morning, but concerns of how much dry air will begin encroaching on the west end of the snowbelt come Wednesday. Northwest PA will likely have a connection with Lake Huron enhancing the snow. This may drift into Ashtabula Co. at times. Highest totals will be across the higher terrain. With the northwest flow, fetch is limited and so is residence time making the decision for Geauga and Ashtabula Co a little more difficult. Believe during the the most intense period, we will be able to get 8 inches in at 24 hour period and have gone with the warning. Lakeshore locations will be borderline as well and have held with an advisory mainly because the winds will be relatively strong and we can have a hard time accumulating the more significant totals. Advisory areas will need to stay tuned for any changes as the lake effect begins to take shape. Regarding Wednesday into Wednesday night, lift is still focused within the dendritic growth zone with plenty of moisture there. The significant drying comes in at H7 with a lowering of the inversion. So the potential for a continuation of moderate to heavy lake effect snow is still a distinct possibility. Winds will be shifting to the west and therefore a shift in the lake effect snow bands will be taking place too. The ridge axis begins to move in late Wednesday evening to begin the tapering process. Outside of the snowbelt, some snow may reach into northwest OH off of Lake MI as the winds back going into Wednesday in addition to what they receive with the clipper tonight/early Tuesday. Highs Wednesday will be near 20 across the snowbelt and mid 20s elsewhere. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... As the lake effect is winding down, another area of low pressure will track across southern Ohio, bringing a light snowfall to at least the southern half of the area. Warm advection precipitation will develop as lift increases across the tightly packed baroclinic zone over central Ohio with light accumulations of 1-2" focused along and south of a line from Toledo to Akron, with lesser amounts to the northeast. One more piece of energy will dive south out of Canada across the western Great Lakes on Friday. There will be a limited amount of moisture to work with but scattered light snow showers will be possible, especially downwind of Lake Erie. Temperatures will remain below normal with highs in the upper 20s and lows in the teens. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... A system will be exiting the region at the start of the period and will have some left over snow chances into Saturday...especially downwind of the lake. After that the models really diverge and confidence is low. Will likely see rounds of wintry precipitation and have gone with chance pops every period. Both the GFS and ECMWF bring low pressure up the Ohio Valley on Sunday. The ECMWF is a good 12 hours faster than the GFS with the surface low. By Monday morning the ECMWF has the Oh Valley low long gone with another clipper approaching from the northwest. At 12z Monday the GFS still has the low just east of the area. These differences are typical of the entire period. Will try to use a blend of the guidance for the period. Hopefully later shifts can fine tune the forecast. Temps during the period will be within a couple degrees or normal with Sunday perhaps the warmest of the three day period. && .AVIATION /00Z Tuesday THROUGH Saturday/... An elongated area of low pressure over LMIC will move east across the area tonight and Tue morning leaving a trough lingering back into the Eastern Lakes into Tue night. Widespread light to locally moderate snow will develop ESE across the area tonight then shift into mainly NE OH and NW PA for Tue into Tue night. Locally heavy bands of lake enhanced snow showers are expected Tue and Tue night around ERI with a lesser threat at YNG and CLE. Southerly winds will shift to the west and northwest behind the low and increase to 15-20 knots with gusts to 30 knots into Tuesday which will produce some blowing of the snow. Expect conditions to drop to a mix of low MVFR/IFR in the snow tonight then improve at TOL, FDY and maybe MFD Tue morning to mix of VFR or high end MVFR. OUTLOOK...Lake effect snow will continue across the snowbelt, mainly east of CLE into Wednesday evening. Another Alberta Clipper is due Wed night into Thursday, bringing light snow to most Ohio terminals. && .MARINE... Low pressure located south of Chicago will track northeast across Lake Erie tonight pulling an arctic cold front across the area. This low will deepen considerably as it merges with another low over Lake Ontario on Tuesday. A Gale Warning has been issued for the central portion of Lake Erie for Tuesday and Tuesday evening as northwest gales to 35 knots develop. A Small Craft Advisory is in effect for the nearshore waters west of Vermilion where winds will increase to 30 knots and may briefly approach gales Tuesday morning. Small Crafts will need to continue on the east end of the lake through Wednesday night as winds are waves are slower to subside. Conditions will improve by Thursday as a weak area of low pressure tracks through the Ohio Valley. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Winter Weather Advisory from 7 PM this evening to midnight EST Wednesday night for OHZ011-012-023-089. Lake Effect Snow Warning from 7 PM this evening to midnight EST Wednesday night for OHZ013-014. PA...Winter Weather Advisory from 7 PM this evening to midnight EST Wednesday night for PAZ001. Lake Effect Snow Warning from 7 PM this evening to midnight EST Wednesday night for PAZ002-003. MARINE...Small Craft Advisory from 3 AM Tuesday to 4 AM EST Wednesday for LEZ142>144. Gale Warning from 7 AM to 10 PM EST Tuesday for LEZ145>149- 165>169. && $$ SYNOPSIS...Oudeman NEAR TERM...Oudeman/Adams SHORT TERM...KEC LONG TERM...Kubina AVIATION...Adams MARINE...KEC

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