Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
365 FXUS64 KMRX 132354 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 754 PM EDT Sun Jul 13 2025 ...New AVIATION... .SHORT TERM... (This evening through Monday) Issued at 112 PM EDT Sun Jul 13 2025 Key Message: Another day of isolated to scattered thunderstorms this afternoon and evening. Main concerns with any strong to severe storm will be winds between 40-60mph and isolated flooding. Discussion: This Afternoon & Evening: An upper-level weather system is hanging out over the Great Lakes, but its not bringing much synoptic support to our region. We`re already seeing some scattered showers and storms early this afternoon, but forecast soundings suggest that the environment is not supported of severe weather. That said, since the airs pretty saturated with PWATS over 1.5" (around 75% of the historical maximum for mid July) a few storms could dump a lot of rain quickly or send out strong gusts up to 40 mph. Monday: The same weather pattern sticks around, with more hit-or- miss afternoon storms. Some of these could produce strong wind gusts or quick downpours that could lead to flash flooding in spots. Temps will rise and humidity will make it feel even hotterexpect heat index values near 100 in most of the southern and central valley. Areas farther north will feel a little cooler but still humid. && .LONG TERM... (Monday night through next Sunday) Issued at 112 PM EDT Sun Jul 13 2025 Key Messages: 1. Daily summer-time convection continues through the long term. Still potential for increased coverage by late week as a trough returns to the eastern U.S. 2. Hot conditions return as an upper ridges strength peaks in the middle part of the work week. Heat indices in the mid 90s to near 100F will become more common across valley locations. Discussion: Trough moves eastward Monday with continued chances for diurnal convection under the hot temperatures. Forecast soundings suggest that effective shear remains about 10 knots or less, with typical summer-time diurnal convection expected. The strongest storms could lead produce wind gusts up to 40 mph and isolated flash flooding of urban and low lying areas. Outside of storms expect it to remain hot and muggy with with heat indices near 100F for much of the southern and central valley. Low to mid 90s are more likely for northern valley into southwest Virginia through the first half of the week. Tuesday and Wednesday are currently looking to be the warmest days. By Thursday a shortwave should be moving through the northern US. With weakening subsidence aloft, we are likely to see increased coverage of afternoon shower and thunderstorm activity... but the temperatures will trend closer to seasonal normals. A humid air mass will keep indices in the 90s and approaching triple digits in southeast TN. Upper ridge looks to become dominant once again next weekend, with daily shower and storm chances remaining likely. && .AVIATION... (00Z TAFS) Issued at 751 PM EDT Sun Jul 13 2025 Cannot rule out a brief shower/storm at CHA over the next few hours. Otherwise, focus will turn to fog and low cig chances overnight. TRI will continue to have the best chances and MVFR to IFR conditions have been included for the time being. Additional isolated to scattered convection tomorrow afternoon. Included PROB30s for most likely times to see activity near a terminal. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 72 95 74 96 / 10 30 10 40 Knoxville McGhee Tyson Airport, TN 71 93 72 94 / 20 30 20 50 Oak Ridge, TN 70 91 71 93 / 20 40 20 50 Tri Cities Airport, TN 68 88 69 90 / 30 40 30 70 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM... AVIATION...KRS