Area Forecast Discussion

KEY MESSAGES

Updated at 1244 PM CDT Sat Sep 19 2026

- Very hot conditions with triple digit heat indices continue. A Heat Advisory is in effect through Sunday for most of Middle Tennessee.

- Low rain chances mainly east of I-65 this weekend with a low chance for strong storms with gusty winds. Higher rain chances spread areawide Monday and Tuesday.

- Cooler air arrives next week with highs mid to late week in the upper 70s (Plateau) and mid 80s everywhere else in Middle TN.

SHORT TERM

(Rest of today through Sunday) Issued at 1104 AM CDT Sat Sep 19 2026

Hang on! Only a few more days of this gross, oppressive heat! High pressure centered over Arklatex will continue to drive afternoon high temperatures across most of Middle TN into the upper 90s and close to triple digits today, tomorrow and Monday. If there's any saving grace, it's the dew points. They're just high enough to warrant continuing the Heat Advisory through tomorrow, but it could be a whole lot worse. Look for Heat Index values of 105 to 107 in the advisory area today and tomorrow. They do start to back off a little on Monday, which should keep us from needing to extend the advisory into the start of next week. As far as rain chances for the rest of the weekend, we aren't centered under the high pressure. This means subsidence won't be as strong here, especially on the Plateau and across our southern counties. Because of this, low chances (20-30%) for showers and storms will be present this afternoon and tomorrow afternoon. Severe risk is very low, but with the heat the way it is, any storm that develops will carry a low wind gust risk of 50-60 mph. Please keep this in mind if you have outdoor plans in the above-mentioned areas through the weekend.

LONG TERM

(Sunday Night through next Saturday) Issued at 1104 AM CDT Sat Sep 19 2026

Ok! Now the good news. Relief from this heat is coming. On Monday, the last official full day of summer, we'll maintain one more day of well-above normal temperatures, but the ridge really starts to break down. This means with the remaining heat, shower and storm chances will be a little more widespread. I've taken a look at forecast soundings on Monday and while not overly impressive, mid-level lapse rates of mid 6's and high triple digit DCAPE values could spell at least a low wind risk. This would match up with the current Day 3 Outlook, though I would say that even though the current Marginal Risk is over the southeast half of the mid-state, any storms that develop will carry a wind risk.

Tuesday. Fall starts at 7:04 pm CT and it's also the day we've all been waiting for. Temperatures will begin backing off (low 90s/low 80s Plateau for highs) and additional, likely even more widespread showers and storms will become possible. This is as a frontal boundary approaches the mid-state. Forecast soundings are similar to Monday, but as we get into the evening, deep layer shear values increase to about 30 kts. Now, I'm not talking about a severe weather outbreak or anything, but storms will be worth watching late afternoon into the early evening. Relief will be felt on Tuesday, that's for sure, but starting Wednesday, behind the frontal passage, temperatures really take a dive. That doesn't mean 60s and 70s for everyone (though the Plateau will see 70s), but the rest of Middle TN will see afternoon highs right around normal for this time of the year (mid-80s). Super excited for that, coupled with what looks like dry conditions until late in the week.

AVIATION

(18Z TAFS) Issued at 1244 PM CDT Sat Sep 19 2026

A more active convective scheme is ongoing over the Plateau, warranting PROB30s this afternoon for CSV and SRB. The surface boundary is sitting just east of BNA, so did not include any precip for the remaining sites this afternoon. Barring any direct impacts from isolated TSRA, VFR conditions are expected to prevail. Variable winds this afternoon will settle into a light southerly flow overnight, picking back up from the southwest Sunday morning.

PRELIMINARY POINT TEMPS/POPS

OHX WATCHES / WARNINGS / ADVISORIES

Heat Advisory until 7 PM CDT Sunday for TNZ005>010-023>033- 056>065-075-077-078-093>095.