Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN
Issued by NWS Knoxville/Tri Cities, TN
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550 FXUS64 KMRX 140536 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 136 AM EDT Fri Jun 14 2024 ...New AVIATION... .UPDATE... Issued at 908 PM EDT Thu Jun 13 2024 Shower activity was less than expected this afternoon. CAMs have dry weather continuing through the overnight period. No changes were made to the forecast for tonight during the evening update. && .SHORT TERM... (This evening through Friday) Issued at 254 PM EDT Thu Jun 13 2024 Key Messages: 1. Hotter weather tomorrow. Very low chance at a shower or thunderstorm. Discussion: Summer weather to continue. Scattered cu fields of variable thickness exist across the wider region, with more consistent coverage over the mountains. Only question this afternoon is if any shower or thunderstorm can fire. The HRRR has a midlevel inversion around 3km, whereas the NAM has a slightly more favorable profile that would allow for convection. 12z HREF paints a consistent showing for a thunderstorm or two over the mountains. It`s not impossible for a brief storm over the Plateau, but it`s not expected. The upper level ridge dominating our weather is currently anchored over the southern Plains, and will slowly move east with time. The 588dm line will move over the Chattanooga metro tomorrow. This corresponds to roughly the 90th percentile for 500 mb heights off the Nashville sounding climatology. Accordingly thanks to the building heights, tomorrow will be slightly warmer than today was, with some locations in the southern valley entering the low 90s. GFS and HRRR have some convection riding the ridge axis tomorrow coming from the midwest but collapsing before entering this area. HREF brings a slight 20% chance for additional northwest flow storms tomorrow afternoon. No significant weather is expected. && .LONG TERM... (Friday night through next Thursday) Issued at 254 PM EDT Thu Jun 13 2024 Key Messages: 1. Above normal temperatures through the period, and right now the hottest days look like Sunday and perhaps Monday. 2. Mostly dry overall, but a few spots especially over the higher terrain will see a shower or thunderstorm with the highest coverage potential expected to occur Monday. Discussion: We start the period with an upper ridge centered to our west, and a large area of surface high pressure extending into our area from the northwest. The upper ridge will build east and will set up residence over the eastern U.S. where it will remain for the remainder of the period. Meanwhile, the surface high will slide east and will continue to extend into our area but will be centered off the the East Coast by early in the week. In this pattern, we will see mostly dry conditions as organized convection will be unlikely under the upper ridge. However, there may be some mainly isolated and diurnally driven convection especially over the higher terrain. Most model solutions show a bit more moisture available on Monday, so the coverage is expected to tick higher Monday afternoon and there may be isolated showers or storms even over valley locations. Temperatures will run above normal for the entire period, with the heat likely peaking Sunday and possibly again Monday as the combination of higher dew points and well above normal temperatures are expected to result in heat index values reaching to around 100 across portions of the central and southern valley. The flow will turn more easterly for the latter periods as the highest heights shift to the northeast, which should result in slightly lower temperatures, although highs will still be significantly above normal for Tuesday through Thursday. && .AVIATION... (06Z TAFS) Issued at 134 AM EDT Fri Jun 14 2024 VFR conditions and light winds are forecast to prevail at all sites. There is a low 10 to 20 percent chance of a few isolated showers or thunderstorms across the mountains in the vicinity of TRI on Friday afternoon, but the probability of any terminal impacts was too low to include in the forecast at this time. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 94 72 93 70 / 0 0 0 0 Knoxville McGhee Tyson Airport, TN 91 69 90 67 / 10 0 0 0 Oak Ridge, TN 91 68 90 66 / 10 10 0 0 Tri Cities Airport, TN 86 65 86 64 / 20 10 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...Wellington AVIATION...JB