Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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105 FXUS64 KMRX 200532 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 132 AM EDT Fri Sep 20 2024 ...New AVIATION... .UPDATE... Issued at 838 PM EDT Thu Sep 19 2024 An update will be issued to extend the chance of showers in NE TN. HRRR shows these showers persisting until around 02Z. Will have slight chance PoPs going a little past that time, until around midnight, as models have been underdone with convection today. Fog is a good bet later tonight, mainly in northern sections and near rivers and lakes, and may be dense in some areas. We will see how this evolves before issuing any products. && .SHORT TERM... (This evening through Friday) Issued at 314 PM EDT Thu Sep 19 2024 Key Messages: 1. A few isolated to scattered showers, and possibly a storm, through early evening. 2. Patchy to areas of fog overnight. 3. Dry and warmer tomorrow, with temperatures around 5 to 8 degrees above normal. Short term models did a poor job earlier today with the current showers across the area. Models kept precip east of I-75 and mainly across our higher terrain areas. Based on latest radar trends and CU field, went ahead and put in a 15 (Slight Chance) POP for most areas through early evening. Most locations will remain dry, but some may cash in on a quick downpour. Tonight, dry with patchy to areas of fog developing after midnight. This will be especially true for any areas that receive a shower this afternoon and evening. Tomorrow, expect a dry day with warmer temperatures as the ridge further builds across the area. Temperatures will be around 5 to 8 degrees above normal. Went a little lower with dewpoints tomorrow based on today`s trends. Went with NBM10. Based on the higher temps, we can expect min RH values down in the mid to upper 30s for some areas. Winds remain light though which will help to alleviate most fire weather concerns. && .LONG TERM... (Friday night through next Thursday) Issued at 314 PM EDT Thu Sep 19 2024 Key Messages: 1. Continued well above normal temperatures (5 to 10F) through the middle of next week. 2. Higher uncertainty for next week, but expect moderating temperatures with gradual increase in rain chances. Discussion: Upper-level 500mb 590-591 dam ridge across the Southern Plains and Lower Mississippi Valley will result in dry and warm weather into the Tennessee Valley through the weekend. Northwest flow aloft and subsidence will bring clear sky conditions and plenty of sunshine. A stronger shortwave will approach the Ohio Valley by the middle of next week with an associated surface low and cold front approaching the Tennessee Valley on Tuesday or Wednesday. Current PoPs are limited to 30 to 40 percent, and a look at the ensembles histogram shows that most of these members are placing around 0.25 inch or less across the region. Only about 15 percent of members have more than one inch of QPF, and with the westerly zonal flow ahead of the front, a drier solution appears more probable. If the cold front can make it through the area, some cooler, near normal, air would be likely late next week. && .AVIATION... (06Z TAFS) Issued at 104 AM EDT Fri Sep 20 2024 Fog development tonight is the main concern, and while the details are uncertain there is a very high probability of significant fog development at TRI in the next few hours. Will continue to include dense fog there with 1/4SM vsby toward sunrise. Confidence lower at TYS, but will continue to include MVFR vsby in fog there. Other than the late night/early morning fog at TRI and TYS, will have a VFR forecast for the period all sites. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 92 65 94 68 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 89 63 91 65 / 10 0 0 0 Oak Ridge, TN 89 63 90 64 / 10 0 0 0 Tri Cities Airport, TN 84 60 85 60 / 10 10 10 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...DGS LONG TERM....JB AVIATION...