textproduct: Morristown

KEY MESSAGES

Updated at 236 AM EDT Sun Aug 16 2026

- Very hot Heat Index's continue today and Monday, especially south and central valley areas. Then it will remain on the hot side through the week but likely a bit less oppressive.

- Next week, best chance for showers and storms will be Monday with some possibly being strong to severe with drier weather expected midweek.

DISCUSSION

Issued at 236 AM EDT Sun Aug 16 2026

The mid/upper level ridge will retrograde and flatten out tomorrow, keeping the MCS activity across the Ohio Valley and Great Lakes. This shift in the ridge should bring in slightly drier air, with PW values falling to around 1.5 inches. Forecast soundings also indicate a stronger cap suggesting less afternoon convective development compared to recent days. A few isolated showers or thunderstorms remain possible across southwest VA and the TN mountains.

With fewer clouds and a lower rain chance, diurnal heating will allow temperatures to climb into the 90s for most locations. Although boundary layer mixing should lower afternoon dewpoints somewhat into the lower to middle 70s. Heat Index values of 105+ degrees are still expected across the central and southern TN Valley. These conditions can lead to heat related illness, especially for those spending extended time outdoors. Limit strenuous activity during the hottest part of the day, drink plenty of water, and take frequent breaks in air conditioning or shade.

On Sunday night, some CAMs indicate remnant MCS convection moving across West Virginia, potentially clipping portions of southwest Virginia. Given the overnight timing, the severe threat looks limited.

Monday will see Heat Index values within the ballpark of what we've experienced this weekend. There's a chance that the boundary layer mixing on Monday brings in lower dew points and the humidity is not technically Heat ADvisory criteria... But it's still going to be hot. Will go ahead and extend the Heat Advisory through Monday for one more day.

A shortwave trough and surface cold front will move through Kentucky Monday morning, sparking off convection as the system approaches the Plateau during the afternoon. The air mass ahead of the front should remain capped into the early afternoon while helping to increase instability. Some shear will also be present, particularly across northern TN and southwest VA, with the NAM showing approximately 30- 40 kt of deep layer shear. An inverted V profile, steep lapse rates, and a deep boundary layer would support strong downdrafts and damaging wind gusts. DCAPE values of 1000+ J/kg further support this concern. The RRFS depicts a fairly intense convective line moving through the area between roughly 7 PM and 11 PM.

Given these factors, the potential exists for a more significant severe weather event Monday afternoon and evening, with damaging straight line winds being the primary concern. Large hail and an isolated tornado cannot be completely ruled out. Those with outdoor plans should have a reliable way to monitor changing weather conditions.

The surface front will push through the area Monday night, bringing slightly cooler temperatures and lower dewpoints for Tuesday. This should end the dangerous heat potential, although temperatures will remain near normal.

The ridge will continue to retrograde through the remainder of the week, resulting in a broad trough across the eastern CONUS. This pattern will increase rain chances through the week as embedded shortwaves move through the larger scale trough and the jet stream settles into the Ohio Valley. Showers and thunderstorms will therefore remain possible, with locally heavy rainfall and lightning continuing to be the primary concerns with stronger storms.

Overall, the most notable hazards through the forecast will be dangerous heat through Monday, localized flooding from repeated thunderstorms, and a potentially more significant severe weather threat Monday afternoon and evening.

AVIATION

(06Z TAFS) Issued at 236 AM EDT Sun Aug 16 2026

Dense fog once again possible at TRI very early this morning. <6SM and BKN CIG already being reported there. TYS and CHA likely to remain calm under SKC or high CIG. Later today trends dry with very low chances of showers or storms, therefore no mentioning in TAF. Rather light SW-Wly winds this afternoon at all terminals.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 98 77 99 76 / 0 0 40 20 Knoxville McGhee Tyson Airport, TN 96 76 95 73 / 0 0 70 50 Oak Ridge, TN 95 74 94 72 / 0 0 60 30 Tri Cities Airport, TN 90 71 89 69 / 10 30 60 40

MRX WATCHES/WARNINGS/ADVISORIES

NC...NONE. TN...Heat Advisory until 8 PM EDT /7 PM CDT/ Monday for Anderson- Bledsoe-Bradley-Hamilton-Knox-Loudon-Marion-McMinn-Meigs- Morgan-North Sevier-Northwest Blount-Northwest Monroe-Rhea- Roane-Sequatchie-West Polk.

VA...NONE.