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

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000 FXUS64 KMRX 260815 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 415 AM EDT TUE JUL 26 2016 .SHORT TERM... Weakening frontal boundary along the Ohio River this morning is becoming nearly stationary. This boundary is expected to be the focusing mechanisms for convection to its south later this afternoon. In the middle levels, a weak 500 mb shortwave trough will further aid in initiating convection as it shifts eastward in the zonal flow aloft late this afternoon. With MLCAPE values of 1500-2000 J/Kg, SFC- 6km shear of 15-20 kt, and PW values reaching to near 2 inches N of the I-40 corridor, any convection that develops will have the potential to produce gusty damaging winds and localized flooding. Although strongest storms will remain over northern half of the CWA, still expect diurnal heating to trigger afternoon and evening convection over southern areas. Although lack of shear should limit severe potential, threat still exists for localized flooding in a moisture laden environment. All activity should gradually weaken with loss of daytime heating before finally dissipating in the overnight hours. Although temperatures will still be about 4-5 degrees above climatological averages, expect that increasing cloudiness with the approaching boundary to keep afternoon high temperatures a few degrees cooler than we have seen in the last several days. .LONG TERM... High pressure ridge over the Southeast the last several days is expected to shift east into the Atlantic by Wednesday. A weak stationary front over the Ohio Valley and mid Atlantic will move little on Wednesday. Rainfall will be concentrated just to the north of the region across Virginia...West Virginia and eastern Kentucky along and north of the boundary the during the day and then increase late in the afternoon across the forecast area. A weak upper level low over MS will also focus more widespread precipitation to the southwest of the eastern Tennessee Valley Wednesday then shift it northeast overnight Wednesday night as a weak surface low moves northeast. Rain chances will stay higher Wednesday night and continue Thursday. Rainfall will be focused near the surface low and along the edge of the ridge. A broad upper trough which moves into the Great Lakes and Ohio Valley including the northern Tennessee Valley early Thursday will remain over the region through at least Sunday. Shortwaves moving across the forecast area will keep rain chances higher with more cloud cover and lower high temperatures a few degrees. The warmest day will likely be Wednesday. Rainfall amounts may reach around an inch around Chattanooga to as much as 3 inches northern Plateau for the 5 day period ending late Saturday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 96 76 94 75 / 40 30 40 40 Knoxville McGhee Tyson Airport, TN 94 74 93 74 / 40 30 30 30 Oak Ridge, TN 93 73 93 74 / 40 30 30 30 Tri Cities Airport, TN 93 70 92 70 / 50 40 40 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$

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