Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 142058 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 358 PM EST Sun Jan 14 2018 .SYNOPSIS...
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A clipper system will bring snow to the region tonight into Monday. Cold temperatures will then continue into mid week.
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&& .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Upper level energy digging into the northern Plains will push a clipper system toward our region tonight. Models concur that a lead s/wv over the central Plains will get pulled northeast ahead of the main upper level low. This feature, along with some isentropic lift, will produce an area of light snow, which will push into the region from the west overnight. Snow amounts of a half inch to an inch will be possible along and north of the Ohio River and along and west of I-75. Farther northeast, light snow will be reaching this area late. Temperatures will drop this evening, then slowly rise as winds increases as winds pick up and clouds thicken. Have allowed for a little colder conditions east and south of Columbus as this radiates out better before thicker clouds arrive.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
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Models concur and forecast follows as such that the clipper system will affect our region Monday into Monday night. First wave of snow will be pivoting off to the northeast Monday morning while the next wave will be poised to move west to east ahead of an arctic cold front during the afternoon and evening. This second wave of snow will be more dynamically driven. Given the two waves of snow, snow accumulations of 2 to 3 inches is expected mainly along and north of I-70, with 1 to 3 inches along and north of the Ohio to I-70. The far southeast should receive between 1 and 2 inches. All in all, have issued a Winter Weather Advisory for the entire region. Temperatures will rebound ahead of the arctic front, resulting in highs ranging from the upper 20s northwest to the mid 30s far southeast. For Monday night, as the arctic front pushes east and southeast, snow will taper off. There is some differences in the models as to how fast the snow will exist our far southeast. Have allowed for gradual tapering off here, but this may have to be tweaked with later forecast. Much colder air will filter back into the region from the west overnight. Lows will range from near 0 across east central Indiana to the lower teens far southeast. These temperatures, combined with wind, will produce wind chill values below zero for much of the region, with 5 below zero to 15 below zero possible for locations in the west. A wind chill advisory will have to be considered with later forecasts. On Tuesday, upper level low will be digging southeast toward the region. At the surface, a trough axis will also be approaching the northwest zones as well. Given that clouds will be intersecting the favored dendritic growth zones, any weak lift will be enough to produce at least scattered flurries. Have this pushing into the northwest zones late. It will remain cold with highs struggling to warm. Highs will range from the lower teens north and west to near 20 southeast.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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Cold air behind another arctic front will be in place over the Ohio Valley by Tuesday evening. As a well-defined 500mb trough moves southeast into the area from the Great Lakes, temperatures above 850mb will cool, with saturated or near saturated conditions expected below about 5kft. Though model soundings do not indicate particularly steep lapse rates in the boundary layer, there will be sufficient overlap with the dendritic growth zone -- especially with surface temperatures falling into the low single digits (maybe below zero where heavy snowpack exists) -- that flurries will be possible under the trough. This will persist into the day on Wednesday. After the trough moves away, high pressure will begin to build into the southeastern states on Wednesday. This will set up a pattern of increasing southerly flow over the Ohio Valley, which will result in a gradual increase in temperatures and dewpoints through the rest of the week and into the weekend. Perhaps the biggest forecast challenge is in the depiction of a wave moving through the southern Great Lakes on Friday morning. Looking at the GFS/CMC/ECMWF, each model has been consistent in its own run-to-run depiction of the wave, but all three remain completely different from each other. That gives too much uncertainty to jump on any of the solutions in particular, but with only the GFS really showing any precipitation, a dry forecast will be maintained. Southeastern ridging will develop going into the weekend, as a deep trough also moves from the southwestern states into the plains. Though there are differences in timing and phase, overall the expectations for the pattern are relatively certain, with meridional flow ahead of the trough leading to warming and moistening conditions in the Ohio Valley -- and eventually rain.
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&& .AVIATION /21Z SUNDAY THROUGH FRIDAY/... High pressure will continue to move east of the region for the remainder of this afternoon. Some local FEW-SCT stratocumulus can be expected. A clipper system will dive southeast from the northern Plains to the western Great Lakes/Middle Mississippi River Valley tonight. Clouds will thicken from the west, and models continue to point to a period of light snow developing and moving east across the terminals late tonight into the first part of Monday. Ceilings will lower into the MVFR category with some pockets of IFR ceilings possible by KDAY. Visbilities will lower into the IFR category. For Monday afternoon into Monday evening, low pressure will move east across the Great Lakes while an arctic cold pushes east into the region. Another period of snow is expected ahead of the front with MVFR/IFR ceilings and visbilities expected as well. OUTLOOK...MVFR/IFR ceilings and IFR/LIFR visibilities possible Monday evening. MVFR ceilings possible at times Tuesday into Wednesday. && .ILN WATCHES/WARNINGS/ADVISORIES...
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OH...Winter Weather Advisory from 1 AM to 7 PM EST Monday for OHZ026-034-035-042>044-051>053-060>062-070>072-077-078. Winter Weather Advisory from 1 PM Monday to midnight EST Monday night for OHZ081-088. Winter Weather Advisory from 4 AM to 10 PM EST Monday for OHZ045-046-054>056-063>065-073-074-079-080-082. KY...Winter Weather Advisory from 1 AM to 7 PM EST Monday for KYZ089>096. Winter Weather Advisory from 1 PM Monday to midnight EST Monday night for KYZ097>100. IN...Winter Weather Advisory from 1 AM to 7 PM EST Monday for INZ050-058-059-066-073>075-080.
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&& $$ SYNOPSIS...Hickman NEAR TERM...Hickman SHORT TERM...Hickman LONG TERM...Hatzos AVIATION...Hickman

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