Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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000 FXUS64 KMRX 171954 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 254 PM EST Tue Jan 17 2017 .SHORT TERM...
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(Tonight and Tomorrow)... Cold front will be crossing the forecast area this evening and pushing east of the area tonight. With very little instability to begin with, the setting sun should limit convection chances even further, and we should not see any thunder after nightfall. Some lingering showers are possible across the east Wednesday morning, then drier air moves in for the remainder of the day. Skies will clear a bit during the afternoon and we should see at least a few peeks of sunshine. Winds will shift from the west behind the front and gusts will diminish. Despite a cold front moving through, the air behind it isn`t too much cooler and highs tomorrow will still be in the 50s. .LONG TERM...(Wednesday night through Tuesday)... An active weather pattern continues through this period as a trio of closed cyclonic circulations move across the lower 48. The first system will remain to our west, with a negatively-tilted trough extending from its center into the TN Valley region Thursday night. A 40+ kt LLJ will efficiently transport Gulf moisture into our area starting late Thursday afternoon, with strong lift provided by favorable positioning of the left exit region of a jet streak. Some weak instability during the time of strongest lift should provide at least a slight chance of thunderstorms for the southern and western half of the area. Drying aloft will bring an end to rain chances Friday morning, and with some afternoon clearing and a continuing SW low-to-mid level flow, temps will reach the mid to upper 60s on Friday. A second closed low tracks NE across the Plains on Saturday, but stays west of the MS River. However it will keep the Gulf open to the TN Valley, with additional moisture spreading back into the area and bringing a chance of showers Saturday. Temperatures will continue to be well above normal, with highs in the 60s. A third and more significant closed low tracks across the Red River Valley to West TN on Sunday. The GFS points toward a warm conveyor belt with tropical connections across the Southeast, along with a coupled jet structure over the TN Valley. If this holds, we could see some significant heavy rainfall and possibly thunderstorms. One caveat might be if strong convection develops along the Gulf coast and cuts off the northerly flow of warm/moist air, which is what the ECMWF hints at happening. Falling temps aloft as the low moves overhead will keep showers going into Monday. Given model consistency and agreement with the general pattern, likely PoPs are warranted for Saturday night through Monday. At this time, temperatures stay warm enough for all liquid precip under the closed low. Drying with an amplifying ridge aloft will build into the area on Tuesday.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 51 61 49 62 / 70 20 50 70 Knoxville McGhee Tyson Airport, TN 48 58 42 58 / 70 20 20 50 Oak Ridge, TN 48 58 42 58 / 70 20 20 60 Tri Cities Airport, TN 47 56 35 57 / 70 30 10 40
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ EMH/DGS

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