Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 070807 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 307 AM EST Wed Dec 7 2016 .SHORT TERM...
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(Today through Thursday) Issued at 307 AM EST WED DEC 7 2016 The latest surface map features a cold front aligned from the eastern Great Lakes down across the central and southern Appalachians. A strong surface ridge of high pressure is nosed in from the Continental Divide down through the central Plains and into the Midwest, outlining the arctic air on its way in. Aloft, a broad and deep trough is in place across the western two thirds of the CONUS, with an upper level low churning across southern Ontario, and a short wave trough moving east across the central Rockies. The models are in good agreement through the short term, with the upper level low continuing to move east into Quebec. Meanwhile, the Rockies short wave will also translate east and allow for an enhanced trough axis to move through the Ohio Valley by Thursday, resulting in mainly the onset of the arctic air moving in across the region. Today will feature a mostly cloudy start to the day, as low clouds remain in place through the mid to late morning, before thinning this afternoon. Temperatures will generally top out in the mid to upper 40s. Tonight, clouds will be on the increase once again as the trough axis approaches from the west, and eventually moves through during the day on Thursday. The models have trended drier with the available low level moisture, suggesting only a few flurries at best for late Wednesday night into Thursday morning across the region, before clouds thin out once again during the afternoon hours. Lows Wednesday night will range from 25 to 30 degrees, with highs on Thursday in the mid to upper 30s for most locations. .LONG TERM...(Thursday night through Tuesday) Issued at 307 AM EST WED DEC 7 2016 A very cold airmass will be settling in over the area Thursday night. The H5 trough axis passes by during the night and models continue to indicate an increase in low level clouds overnight with a marginal upslope component to the low level flow. Soundings show cloud temps in the -8C to -12C range and this should be good for flurries to develop late Thursday night and continue into the day on Friday. Temperatures on Friday will likely remain below freezing for most locations giving us our coldest day since last February. High pressure then settles in over the region Friday night. Mid and high clouds streaming overhead may disrupt radiational cooling some, but temperatures will still likely fall deep into the teens. The weekend starts dry and chilly on Saturday, and then turns unsettled as a shortwave moves across the Upper Midwest and into the Ohio Valley. This forces a cold front across the state Sunday into Sunday night. Models are still having difficulty with this system and forecaster confidence on the details is lacking. Models are trending colder with the temperature profile and this draws into question precip type. Models do show a 50kt H85 jet which should draw enough warm air northward to cause the bulk of any precip to fall as rain. However, we will continue with the idea of a chance of rain/snow Sunday morning, then rain likely Sunday afternoon and evening before precip transitions back to a rain/snow mix late Sunday night into Monday morning. This system exits leaving what should be dry and seasonably cool day behind on Tuesday. Looking further out...while it appears we get a brief taste of Arctic air late this week, longer range models bring in a true Arctic blast later next week preceded by some accumulating snow. Certainly something to keep an eye on with future model runs...
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&& .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1251 AM EST WED DEC 7 2016 MVFR ceilings look to hang on through the mid to late morning hours, before scattering out. Some mid-level cloud cover will then be on the increase towards the end of the forecast. Northwest winds will average around 5 kts or less through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GEOGERIAN LONG TERM...ABE AVIATION...GEOGERIAN is the U.S. government's official web portal to all federal, state and local government web resources and services.