Subj : Area Forecast Discussion For Tri Cities, TN/VA To : All From : Sean Dennis Date : Tue Jun 30 2026 07:00:01 766 FXUS64 KMRX 300656 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 256 AM EDT Tue Jun 30 2026 ....New DISCUSSION, AVIATION... ..KEY MESSAGES... Updated at 232 AM EDT Tue Jun 30 2026 - Isolated to scattered showers and thunderstorms this afternoon in the mountains and adjacent foothills, some may be strong to severe. - Very hot this week with high temperatures well into the 90s common. Afternoon heat index values will climb to around or above 100 degrees in in most valley locations multiple days. && ..DISCUSSION... Issued at 232 AM EDT Tue Jun 30 2026 The coverage and intensity of storms this past evening exceeded expectations, outperforming what the CAMS showed. We had a very unstable air mass with SBCAPE over 4000 J/kg with little to no capping over NE TN/SW VA. Today, forecast soundings suggest a similar environment, possibly even more unstable as the NAM shows a 700-500 mb lapse rate around 8 C/km this afternoon. CAMS pick up on convection developing along the NC border with a southwest drift, but outflow boundaries will likely initiate additional storms in the Tri-Cities area and NE TN foothills. Heavy downbursts that cause damaging wind gusts and hail up to quarter size are possible. On Wednesday the cap strengthens as the large midlevel ridge drifts a little to the east, becoming centered over eastern KY. Convection will shift to GA/AL and possibly our SW NC/SE TN counties where the cap will be weaker. Again, there will be ample instability for strong to severe storms if the cap can be broken Wednesday afternoon. A Heat Advisory will be in effect from today through Thursday. High temperatures are expected to be in the 90s across all but the higher elevations each day this week and through the weekend, with mid to upper 90s across portions of the TN Valley. Heat index values around or above 100 will common in the afternoons, and heat index values may exceed 105 across portions of the area, especially Wednesday and Thursday. The Heat Advisory may eventually need to be extended longer in time as it still looks very hot Friday and into at least the beginning of the weekend. A short wave may bring more precip and slightly lower temperatures by Monday, but confidence in the details is low that far out. && ..AVIATION... (06Z TAFS) Issued at 232 AM EDT Tue Jun 30 2026 Calm night with high clouds or SKC. TRI does pose a chance to have fog development before sunrise. Continued the 03z line of MVFR BR there. Later today could possibly be a repeat of yesterday with showers and storms shifting down from the north, potentially impacting TRI, possibly TYS as well. VCSH added to TYS and a PROB30 TSRA added for TRI. && ..PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 97 77 98 77 / 0 0 30 20 Knoxville McGhee Tyson Airport, TN 93 74 95 75 / 10 10 10 10 Oak Ridge, TN 94 75 96 75 / 10 0 10 0 Tri Cities Airport, TN 92 71 95 71 / 30 10 0 10 && ..MRX WATCHES/WARNINGS/ADVISORIES... NC...Heat Advisory from 11 AM this morning to 9 PM EDT Thursday for Cherokee-Clay. TN...Heat Advisory from 11 AM EDT /10 AM CDT/ this morning to 9 PM EDT /8 PM CDT/ Thursday 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 from 11 AM this morning to 9 PM EDT Thursday for Lee-Russell-Scott VA-Washington VA-Wise. && $$ DISCUSSION...DGS AVIATION...KS --- MBSE BBS v1.1.7.2 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (618:618/1) .