Area Forecast Discussion
Issued by NWS Wilmington, OH

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255 FXUS61 KILN 221019 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 619 AM EDT Thu Mar 22 2018 .SYNOPSIS... High pressure and a dry, but seasonably cool airmass will build across the region today through Friday. A low pressure system will move into the area this weekend, bringing a chance for rain and snow late Friday night into Saturday night. High pressure and dry conditions will return for early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Clearing is continuing to work slowly east across the area early this morning with about the western two thirds of our fa now clear. Given the fresh snowfall, temperatures have not fallen off as much as might be expected under clear skies and relatively light winds. That being said, will still allow for temperatures to fall into the upper teens to lower 20s across at least our west since we still have several hours before daybreak. Surface high pressure will build in from the west through this afternoon. With some lingering lower level moisture and still some weak low level CAA, think we could see a few fair weather cumulus develop, especially across our eastern areas. Highs today will generally be in the low to mid 40s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... The surface high will shift slowly east across our area tonight through Friday. This will lead to dry and continued cool conditions. Lows tonight will drop into the low to mid 20s with highs on Friday ranging from the low 40s in the north to the mid 40s in the south. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Friday night a potent mid level disturbance will push east out of the Mountain West with surface cyclogenesis occurring over western Kansas. Through Friday night the surface low will pull east with strong isentropic upglide commencing. The latest GFS, NAM, and ECMWF all show a LLJ approaching 40 kts forcing warm moist ascent across Kentucky, Indiana, and Ohio. Looking at the 300 kelvin surface reveals very strong ascent with condensation pressure deficits at zero starting Saturday morning and continuing into the late afternoon. Across our northeastern zones there will likely be a cut off in the precipitation as low level moisture fields indicate dry air remaining entrenched towards Columbus and Kenton. The main area of concern will across our central and southern zones (towards Wilmington, Cincinnati, Connersville, and Batesville). Along this northwest to southeast axis the mid level wave will pass overhead allowing thermal profiles to mostly remain below freezing through the column. Strong overrunning and omega (from the PVA and WAA) near the DGZ will produce a band of moderate snow. On the latest GFS, ECMWF, GEFS, and EPS there are consistent signals for an accumulating snow event, and perhaps even significant. Many factors will come into play here though that will affect snow amounts. These will include surface temperatures, low level thermal profiles, track of the surface low, and road temperatures (to name a few). Current forecast soundings on the GFS show a slightly colder thermal profile than the NAM with the ECMWF being similar. As of now the area of highest confidence for remaining all snow will be just north of the Ohio river. Areas south of the Ohio river will likely mix with pellets and go to rain possibly. Still though, this type of strong vertical motion near the DGZ (with the support of an FGEN band out ahead of the low level low pressure) snowfall totals can quickly add up. It should also be noted that with the strong upper level wave moving across at this time mid level lapse rates quickly steepen with elevated instability forming. Given the latest exceedance probabilities on the GEFS and EPS have gone ahead and issued a Winter Storm Watch starting late Friday night through Saturday night across portions of east central and southeast Indiana, northern Kentucky and western Ohio. Late Saturday night into Sunday morning the mid level wave will begin to wash out and head southeast. For the most part Sunday into Monday will remain dry as mid level ridging moves overhead. Any snow that did fall on Tuesday will quickly melt as high temperatures warm close to 50 degrees on Monday. By Tuesday an upper level low will remain quasi-stationary over the southwestern United States. This will allow for much warmer weather with highs approaching 60 degrees by Wednesday. Also, the pattern looks to be wet with multiple rounds of upper level disturbances crossing the region. && .AVIATION /10Z THURSDAY THROUGH MONDAY/...
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Some patchy MVFR fog may affect KLUK for the first hour or so of the TAF period. Meanwhile, the back edge of the mid level clouds is continuing to make a slow eastward push and should clear KCMH/KLCK in the next couple of hours. High pressure and a dry airmass will move into the region through tonight. This will lead to VFR conditions through the remainder of the TAF period. OUTLOOK...MVFR/IFR ceilings and visibilities are possible Friday night through Saturday night. MVFR ceilings are possible again on Monday.
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OH...Winter Storm Watch from late Friday night through late Saturday night for OHZ042-060-061-070>072-077>081. KY...Winter Storm Watch from late Friday night through late Saturday night for KYZ090>093-095>099. IN...Winter Storm Watch from late Friday night through late Saturday night for INZ050-058-059-066-073>075-080.
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&& $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...Haines AVIATION...JGL is the U.S. government's official web portal to all federal, state and local government web resources and services.