Area Forecast Discussion

KEY MESSAGES

Updated at 217 PM EDT Sat Sep 19 2026

- Well above normal temperatures to persist into early next week.

- Expect isolated to scattered showers and storms each afternoon today through Monday, then chances for showers and storms will be higher Tuesday and Wednesday.

- A few storms may be strong to severe with damaging winds the primary threat each afternoon today through at least Monday. Localized flooding will be possible each day through Wednesday as well.

- Cooler conditions are expected to arrive by the latter half of the coming week.

DISCUSSION

Issued at 217 PM EDT Sat Sep 19 2026

The upper ridge that has been sponsoring our recent hot and mostly dry weather is centered off to our west and will be gradually breaking down through the remainder of the weekend into the early part of the week, with heights over our area showing a gradual decreasing trend. It remains quite hot this afternoon, with heat index values not far either side of 100 across many southern and central valley locations. We will see continue to see isolated to scattered showers and storms around this afternoon and evening. The atmosphere today features minimal shear, but moderate instability, high PWAT values, steep low level lapse rates and DCAPE values either side of 1000 J/kg suggest an environment in which a few of the stronger storms could produce damaging winds.

Models generally show a bit less coverage of storms Sunday afternoon with an uptick in coverage on Monday, but overall soundings do not look much different from today and we will continue to see the threat of a few storms becoming strong to severe with damaging winds the primary threat. PWAT values will remain high as well, so locally heavy rainfall will be possible with a threat of localized flooding. It will also continue to be quite hot for this time of year both days.

An upper low near the western Great Lakes region will move east and southeast during the mid week period, and a cold front will move through our area sometime around Wednesday. We will see an increase in showers and storms Tuesday and Wednesday, along with a moderating trend in temperatures as the heat loses its grip on the area.

We will be in northwest flow aloft for the latter periods of the forecast with upper ridging to our west and a trough centered to our east. We may still have a few showers and storms around, but overall Thursday through Saturday should be drier and cooler. High temperatures are expected to be near to a bit below normal all three days.

Lastly, until the expected relief from the heat arrives, Chattanooga will continue to build onto their record streak of 90 degrees or higher. They have climbed above 90 again today so they currently sit at 47 days, with a few more days likely to add to the streak. The first day where the official forecast is below 90 is Wednesday. If they hold on to the 90+ streak through Tuesday, that would bring the total up to 50 days.

AVIATION

(18Z TAFS) Issued at 1232 PM EDT Sat Sep 19 2026

Isolated to scattered showers and storms will be around this afternoon, and will include prob30 thunder groups all three sites. The other concern will be possible fog development tonight mainly TRI. If rain occurs at TRI this afternoon/early evening then the chances for significant fog will increase, but that is still unknown at this time. For now will add several hours of MVFR fog late tonight at TRI, but dense fog is a possibility again.

PRELIMINARY POINT TEMPS/POPS

MRX WATCHES / WARNINGS / ADVISORIES

NC...NONE. TN...NONE. VA...NONE.