Subj : Area Forecast Discussion For Tri Cities, TN/VA To : All From : Sean Dennis Date : Fri Jul 03 2026 07:00:02 328 FXUS64 KMRX 031049 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 649 AM EDT Fri Jul 3 2026 ....New AVIATION... ..KEY MESSAGES... Updated at 646 AM EDT Fri Jul 3 2026 - Scattered showers and thunderstorms this afternoon; some may be strong to severe with gusty winds and lightning. - Very hot temperatures continue with afternoon heat indices reaching 100 to 105 degrees in most valley locations, the heat advisory remains in effect through Independence Day. - Temperatures drop to normal summer values with continued diurnal daily random storm chances next week. && ..DISCUSSION... Issued at 239 AM EDT Fri Jul 3 2026 As a legendary DC character Firestorm would say, the heat is on. And it's still on. The dominant 500 mb ridge is with us for another day, before it generally weakens until dissolution into the mean flow. Once the dissolution occurs over the weekend, we'll steadily edge off the worst of the heat and return to normal summer patterns. Before we can get to the greener grass, we have Friday and Independence Day to go through with excessive amounts of temperature. I'm not as confident on us hitting forecast NBM temperatures today, so hedged them down slightly. The biggest interrupter on hitting the highs is whether or not convection fires before we can obtain peak heating. HRRR/RRFS both have had good convective coverage for today, which lends more credence to storm activity than the past two days when the HRRR has been very quiet. There is a very weak upper level wave way aloft, this feature was located over Middle Tennessee on Thursday and storms were able to fire successfully over there. Probably the limited on storms still remains the strong 500 mb ridge, with 700 mb temperatures hovering near the record highs. It's not a true thermal cap, but clearly the last couple of days storms have struggled to fire outside of the upslope regime in western Carolinas. Storm wise the same atmospheric thermal ingredients are in place. Lots of CAPE, lots of DCAPE, even high TT index numbers for the elder weather enthusiasts. If TT is not your flavor and you're looking for a more complex index, SWEAT has values of 400 in the southern valley, indicative of decent thermodynamics favorable for strong thunderstorms. Having said all of that meteorological jargon, I'm still not sold on how many storms will be able to reach severe thresholds and that's I think in part to the warm 700 mb temperatures and the amount of dry air present in the atmosphere. Between the two and watching the last two days, I'd probably still expect to see skinny updrafts periodically flirting with severe height criteria, better odds if updrafts can congeal to form a more resilient and larger updraft width. Just likely more coverage today as I've already mentioned. Saturday looks to be a tad "cooler". Our two favorite CAMs have less, but still present diurnal coverage, and the storm risks are the same with gusty winds and lightning. Good news is generally storms collapse in these diurnal patterns with sunset, and thus as long as your fireworks show is after dark, it's unlikely to have a confrontation with Nature's sparklers. Hopefully. Heading into next week, the loss of the prominent ridge will lead to a decrease in the temperatures back to normal ranges, and guidance indicates a continued daily pattern of diurnal activity, with potentially a weak shortwave edging into the Mid South region by midweek. Nothing particularly significant on the horizon, just regular July. && ..AVIATION... (12Z TAFS) Issued at 646 AM EDT Fri Jul 3 2026 The main aviation impact today will be developing showers and storms during the afternoon hours. Within these storms, reductions to MVFR or less can be expected with coverage likely to be better around CHA and TYS. Throughout the evening, activity is expected to decrease area-wide. For places that see notable rain, fog development is likely, but it has been left out of the TAFs due to limited confidence. && ..PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 98 75 97 75 / 50 10 20 20 Knoxville McGhee Tyson Airport, TN 96 74 95 74 / 40 20 20 20 Oak Ridge, TN 97 74 96 73 / 30 20 20 20 Tri Cities Airport, TN 96 70 96 70 / 30 10 20 20 && ..MRX WATCHES/WARNINGS/ADVISORIES... NC...Heat Advisory until 8 PM EDT Saturday for Cherokee-Clay. TN...Heat Advisory until 8 PM EDT /7 PM CDT/ Saturday for Anderson- Bledsoe-Blount Smoky Mountains-Bradley-Campbell-Claiborne- Cocke Smoky Mountains-East Polk-Grainger-Hamblen-Hamilton- Hancock-Hawkins-Jefferson-Johnson-Knox-Loudon-Marion-McMinn- Meigs-Morgan-North Sevier-Northwest Blount-Northwest Carter- Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea- Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi- Union-Washington TN-West Polk. VA...Heat Advisory until 8 PM EDT Saturday for Lee-Russell-Scott VA- Washington VA-Wise. && $$ DISCUSSION...Wellington AVIATION...BW --- MBSE BBS v1.1.7.2 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (618:618/1) .