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KEY MESSAGES

Updated at 148 PM 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 148 PM EDT Fri Jul 3 2026

The dominant H5 ridge that has been producing the hot conditions this week will begin to weaken today and tomorrow as shortwave energy across northern half of the CONUS suppresses the ridge and shifts it off the southeast coastline. Satellite and radar imagery are already showing the effects of this, with scattered convection popping off by 1pm EDT this afternoon across the southern Appalachian region and further south. Expect to see the central and southern areas have the best coverage for storms this afternoon as there's a more pronounced weakness on the southern periphery of the ridge there. Instability is sufficient enough for some marginally severe storms capable of damaging winds this afternoon with DCAPEs in the 1,000 to 1,500 J/kg between northern Georgia and the I-40 corridor and mixed layer CAPE values in excess of 2,500 J/kg. Instability isn't a problem today but lack of shear and a forcing mechanism to congeal storms into something more than a small, singular updraft, means that the overall threat of severe storms is low. If some sort of clustering happens, then some notable damaging winds could occur, but the threat seems isolated overall. Areas north of the I-40 corridor are more firmly beneath the center of the ridge so I would expect coverage to be more isolated in that region. Instability is a little less there too, so storm severity should be lower still.

Storm coverage tomorrow looks diurnally driven and terrain focused like is typical in the summertime - likely less than what we'll eventually see this afternoon. PoPs reflect this. It should be a tad cooler though as the H5 heights continue to fall. Still, it will be warm and dewpoints will remain entirely too high if you ask me. With dewpoints in the low to mid 70s and forecast highs in the mid 90s, heat index values of 100 degrees or more seem highly likely. The heat advisory was extended into Saturday and I don't see any reason to deviate from that. The combination of the July 4th Holiday activities and the forecast head indices justify the advisory.

Otherwise, as we move from Sunday into early next week, the loss of the prominent ridge will lead to a decrease in the temperatures back to normal ranges. Guidance isn't in great agreement on the details of the upper pattern, but generally 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

(18Z TAFS) Issued at 148 PM EDT Fri Jul 3 2026

Scattered SHRA/TSRA are developing across East Tennessee this afternoon, primarily south of I-40. Have a TEMPO for this at KCHA but coverage further north should be isolated enough to only justify a PROB30 at KTYS and simply a mention of vicinity showers further north. Aside from the MVFR categories with convection, VFR flight conditions should prevail through the period. There was some fog present on satellite this morning in southwest Virginia and the KY/TN border. A persistence forecast dictates not including any fog at KTRI but it's worth noting that some guidance has it in there.

PRELIMINARY POINT TEMPS/POPS

Chattanooga Airport, TN 74 96 75 95 / 10 20 20 60 Knoxville McGhee Tyson Airport, TN 73 95 73 94 / 10 20 20 60 Oak Ridge, TN 73 96 73 94 / 10 10 20 60 Tri Cities Airport, TN 70 96 70 94 / 10 10 20 50

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.