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

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000 FXUS64 KMRX 181909 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 309 PM EDT Fri Aug 18 2017 .SHORT TERM (Today and Saturday)...
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A few areas in NE TN and SW VA will continue to experience scattered showers with isolated thunderstorms until the late afternoon as the frontal boundary continues to move through the region. With mid and upper level drier and cooler air filtering in to the area from the NW...clouds will slowly clear through the evening. Enough low level moisture will be left through the night...especially in areas still receiving rainfall this afternoon...for patchy dense fog development through the early morning. .LONG TERM (Saturday night through Friday)... The main theme for Saturday night through Monday is developing ridging into the southeast United States and southern Appalachians. This ridging will tend to suppress any convection development with a fairly dry airmass across the region. PWs will be between 1 and 1.2 inches. Some upslope flow into the mountains, especially Monday, that isolated showers/thunderstorm possible by confidence is low. The eclipse forecast overall looks favorable for mid/late August with only scattered cloud cover between 18-20Z. For Tuesday, ridging begins to break down with moisture and instability returning to the Tennessee Valley as an upper trough moves across the western Great Lakes. Will include low chance PoPs. For late Tuesday night and Wednesday, a fairly strong upper trough establishes itself across the Great Lakes/northeast United States with associated cold front swing across the Tennessee Valley. Model soundings show airmass will be moist and unstable with CAPES of 1000- 1500. Main concern will be isolated strong/gusty winds, lightning and heavy rains. WBZ are fairly high (above 12kft), so hail threat is minimal. Fair strong surface ridging will build into the Ohio Valley with drier weather anticipated. Only caveat is an inverted trough near the spine of the Appalachians. The convergence along this trough may produce isolated convection for the latter half of next week.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 69 91 70 92 / 0 0 0 10 Knoxville McGhee Tyson Airport, TN 67 89 67 91 / 0 0 0 10 Oak Ridge, TN 67 89 67 90 / 0 0 0 10 Tri Cities Airport, TN 64 88 61 89 / 10 0 0 10
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ JW/DH

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