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

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000 FXUS64 KMRX 141924 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 324 PM EDT Mon Aug 14 2017 .SHORT TERM (Tonight and Tuesday)...
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A weak short wave is moving through the region...riding along a old boundary that has been stretched across the area. As a result...a band of convection has developed and is moving through the MRX CWA this afternoon and evening. There is minimal upper level support and little in the way of instability. However...PWs are quite high...averaging around 2 inches...so expect the main concern from the convection will be the potential for heavy rainfall. This activity will diminish into scattered showers overnight. The boundary will slowly begin to shift south and east on Tuesday but should remain the main focus for area weather and will continue to generate scattered showers and thunderstorms across the Southern Appalachian Region through the day. .LONG TERM (Tuesday night through Monday)...A ridge through the mid and upper levels will be near the Gulf coast through the rest of the work week, with a weak westerly flow through the column across East TN. Any enhanced precip chances above the typical summertime scattered diurnal convection will depend on weak disturbances in the westerly flow, which models typically do not depict well. So with the finer details being uncertain, the forecast will favor the typical summer pattern of chance PoPs following a diurnal trend. Friday may have slightly higher precip chances compared to Wednesday and Thursday, when a low pressure system is expected to track across the Great Lakes, with the tail end of a weak cold front pushing toward our area. Temperatures should be close to normal for this time of year. For the weekend and Eclipse Day, the pattern amplifies with a ridge building over the Plains and a trough along the east coast, with surface high pressure area over the Ohio Valley and Great Lakes. This puts our area in a generally N-NW flow, favoring dry/stable conditions and weak forcing. The GFS brings a shortwave trough across the area Saturday night/Sunday, but moisture will likely be pretty limited in this pattern. Will have slight chance PoPs in the forecast each afternoon due to uncertainty about the convective potential this far out. If this pattern holds, eclipse viewing should be good for most locations - mostly sunny with just a slight chance of afternoon showers and near normal temperatures.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 73 88 73 89 / 50 40 20 40 Knoxville McGhee Tyson Airport, TN 71 86 69 88 / 60 40 20 30 Oak Ridge, TN 71 86 71 89 / 50 40 20 30 Tri Cities Airport, TN 69 83 67 87 / 60 50 20 20
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ MJB/DGS

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