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

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000 FXUS64 KMRX 281853 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 253 PM EDT Tue Mar 28 2017 .SHORT TERM...(Tonight and Tomorrow)... Cloud cover will continue to diminish tonight as the upper level shortwave that brought yesterday`s showers and thunderstorms continues to push east. With less cloud cover, temperatures will be cooler than last night, around 50 in most locations and in the mid to upper 40s in the Smokies. Cooler temperatures combined with residual boundary layer moisture from the rain should aid in fog formation tonight and areas of fog are possible across the area tomorrow morning. After sunrise, a ridge will build overhead throughout the day and keep skies mostly sunny. This will allow for high temperatures in the 70s tomorrow, with locations in the southern Tennessee Valley potentially approaching 80 degrees. Just how warm it gets will depend on how much fog/low stratus develops tonight and how long it takes for it to clear out tomorrow morning. .LONG TERM...(Wednesday night through Tuesday)... A ridge through the mid and upper levels will be over our area to start the period, while at the surface, low pressure will be tracking slowly east- northeast from the southern Plains to the Ozarks. The southerly low level flow ahead of this system will be increasing through Thursday, bringing mild temps in the mid/upper 70s and rising dewpoints. Afternoon destabilization may bring scattered/isolated showers/storms Thursday afternoon to southern and western sections. A downslope flow of 30-40 kts at 850 mb across northern sections should help cap convection in that area through Thursday night. The model trend with this system has been slower, and expected convection near the Gulf Coast may also limit northward moisture transport and increase midlevel stability through Thursday night. As a result, will delay the onset of categorical PoPs until Friday morning when the upper trough axis and jet streak move across the area. At this time any widespread severe storm threat appears to be south of our area, but with a 40-50 kt LLJ, some strong gradient winds in the mountains and foothills may be possible Thursday night. Model differences and run-to-run timing changes lead to some uncertainty regarding the end of precip, but will continue low PoPs into Friday evening. The weekend will be dry as the amplified pattern aloft brings another ridge across the region. The general model consensus is for a closed low to track from the southern Plains toward the TN/OH Valley region on Monday/Monday night, but there are differences in model timing and positioning of the low that add uncertainty. Will have high chance PoPs for the area during that period, with decreasing PoPs through Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 51 79 57 79 / 10 0 10 30 Knoxville McGhee Tyson Airport, TN 51 75 55 77 / 10 0 10 30 Oak Ridge, TN 52 76 55 77 / 10 0 10 30 Tri Cities Airport, TN 49 73 50 73 / 10 0 10 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ EMH/DGS

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