Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 170554 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 1254 AM EST Sat Feb 17 2018 .SYNOPSIS... A cold front that produced widespread rain has moved south, allowing colder temperatures and drier conditions to visit tonight as high pressure crosses Northern Ohio. On Saturday, low pressure traveling over the Southern Appalachians will bring precipitation mainly to southeastern locations. High pressure and dry weather will return for Sunday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Persistent stratocumulus clouds have lifted a bit over the past several hours, now generally in the 2500-4000 foot range over the ILN CWA. With surface high pressure moving east of the area overnight, a wind shift to the southeast is eventually expected, which will lead to a moistening of a deeper layer of the column through the morning hours. Made a few adjustments to the forecast going into tomorrow, mainly noting that with respectable RH in the boundary layer (wet bulb temperatures above zero through a couple thousand feet at onset of precipitation) the chances for a lengthy period of snow appear very slim. If anything, some wet flakes near onset will be more likely to give way to rain -- with little in the way of accumulation. No big changes to T/Td/Sky/Wind grids overnight. Previous discussion > Area is under a colder northwest flow well north of a departing cold front. Any lingering light rain in far southeast counties will end shortly. This will leave mostly cloudy skies resulting from shallow low level moisture trapped under a subsidence inversion associated with surface high pressure approaching from the northwest. According to model soundings, clouds will persist through the overnight hours even as the 1029mb high pressure travels across Northern Ohio. A blend of model temperature guidance yields lows ranging from the lower 20s far north, to the mid 20s Dayton and Columbus, up to the upper 20s Cincinnati and Portsmouth. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... For Saturday, models are in pretty good agreement in bringing low pressure across the Southern Appalachians. Precip forecast to develop ahead of the low should mainly affect locations south of I- 71. 1000-850mb thickness and model soundings indicate a marginal thermal environment for snow crystal development and accumulation. In other words, rain mixing with snow, and high temps in the upper 30s to around 40, will limit snow accumulation to an inch or less. While precip ends quickly Saturday night as high pressure returns behind the departing low, temperatures will retreat to around 30 for overnight lows. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Sunday will be the least active weather day in the extended as high pressure traverses the Ohio Valley. Under sunshine, highs will moderate into the 40s to lower 50s. Models continue to advertise an active weather pattern for next week. Thus, the threat for additional flooding will continue. The upper level flow pattern becomes amplified as a strong subtropical ridge builds off the southeast U.S. coast while large scale mid level troughing develops across western Canada/western U.S. This setup will transport rounds of moisture northeast across the Great Lakes and Ohio Valley. The first round of precipitation is expected Sunday night into Monday as a low level/moist jet in association with a warm front pushes northeast across the area. In the warm sector, highs will warm into the 60s most locations on Monday. For Monday night into Wednesday night, a very slow moving frontal boundary will be the focus for more rounds of precipitation. It will be unseasonably warm on Tuesday with some cooler air slowly moving back in by Wednesday. Tuesday temperatures will vary with higher chances of rain for the northwest with the least in the southeast. This will allow highs to range from the mid 60s northwest to the mid 70s southeast. Showers and a slow frontal passage will cool temperatures back down on Wednesday. By weeks end, there could be a respite in the probability for precipitation by Thursday as the front tries to move east/southeast of the region. However, activity will likely ramp up again by Friday and into next weekend as s/wv energy begins to affect the Great Lakes and Ohio Valley once again. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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Dry conditions will be in place for the overnight hours and to start out the day on Saturday. A mix of VFR and MVFR cigs will be present overnight. On Saturday a surface low will move southeast of the TAF sites and an upper level disturbance will move primarily near the northern TAF sites. The combination of these two features will bring some light precipitation to the region in the form of rain and snow. Southern area TAF sites will see more in the way of rain, while the northern sites will see a mix of rain and snow. Additional MVFR cigs will move into the region during the day on Saturday. Precipitation will begin to taper off at the end of the TAF period. OUTLOOK...MVFR conditions will continue Saturday night into Sunday morning. MVFR conditions are possible again at times from Monday through Wednesday.
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&& .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Coniglio NEAR TERM...Coniglio/Hatzos SHORT TERM...Coniglio LONG TERM...Hickman AVIATION...Novak is the U.S. government's official web portal to all federal, state and local government web resources and services.