Heat index values reached 105 to 109 degrees on successive afternoons. On the 24th and 25th, the heat index peaked at 110 degrees in Lincoln County.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS HUN wrote it up.
Heat index values reached 105 to 109 degrees on successive afternoons. On the 24th and 25th, the heat index peaked at 110 degrees in Lincoln County.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Huntsville, AL wrote its last area forecast discussion before the first event at Aug 22, 11:07 AM CST, 2 hours 53 minutes earlier.
Area Forecast Discussion National Weather Service Huntsville AL 1207 PM CDT Tue Aug 22 2023 ...New AVIATION... .NEAR TERM... (Rest of Today) Issued at 943 AM CDT Tue Aug 22 2023 Current conditions are on par for another muggy hot day across the Tennessee Valley. Temperatures are are hovering around 80 degrees as they make the climb into the mid 90s by this afternoon. Dew points are our main conflict today as they will drive our heat index. With current dew points in the mid to high 70s the only slight change to the forecast was reducing daytime dew points by a few degrees to keep them in the mid 70s. This will limit our heat index to max out right around 105. && .SHORT TERM... (Tonight through Friday) Issued at 323 AM CDT Tue Aug 22 2023 Clear/calm conditions will allow temperatures to drop off during the evening and overnight hours -- though it may still feel uncomfortable even overnight as low temperatures will bottom out in the low to mid 70s in most locations. We may need to extend the Heat Advisory overnight to cover impacts overnight in future forecast updates. Another hot/humid day is expected across the Tennessee Valley on Wednesday as the upper-ridge really begins to flex its muscles. This will place high temperatures in the mid to upper 90s by the afternoon hours. Guidance is hinting at slightly lower dewpoints on Wednesday, which will keep our peak heat index values in the 105-109 range (Advisory levels) across most of the region. In fact, the spatial area of where we actually hit criteria may be a little smaller in the Plateau region (DeKalb, AL and Franklin, TN) with dewpoints running closer to 70 degrees. This would keep peak heat index values below the 105 degree Advisory threshold in our far eastern counties. The heatwave will peak Thursday/Friday as the upper-ridge and its associated "heat dome" settles over the Tennessee Valley. It's possible we see the warmest temperatures of the summer, with both HSV/MSL progged to reach or exceed the 100 degree mark both days and mid to upper 90s expected across the rest of the area. At bare minimum, Heat Advisories seem probable during this timeframe and its possible that an Excessive Heat Warning may be needed for portions of northwest/north central Alabama if dewpoints trend a little bit higher. && .LONG TERM... (Friday night through Monday) Issued at 323 AM CDT Tue Aug 22 2023 The upper level ridge will begin to flatten by Friday night in response to an upper shortwave moving over the Great Lakes region. This shortwave eventually deepens into a trough over the eastern CONUS into early next week, with another impulse moving along the main flow towards the region by early next week. At the surface, a cold front is forecast to traverse southward over the Tennessee Valley from Friday night through Saturday. This surface boundary will slowly make its way towards the northern Gulf coast, with surface high pressure building in over the Ohio Valley to the north. An inverted trough looks to then form by early next week over the Southeast and up into the lower Ohio Valley. Overall, model guidance is pessimistic with precipitation chances associated with the cold front into Saturday. However, with sufficient instability and moisture, maintained low chances (~15%) of showers and perhaps a couple storms through the day on Saturday as the front moves over the area. Sunday is expected to remain dry however, as the aforementioned upper shortwave moves into the Tennessee Valley region and inverted trough feature sets up at the surface on Monday, low chances (15-30%) for showers and storms returns to the area. Model bulk shear values are fairly meager for Monday; thus, not anticipating severe weather at this point. The good news is that a gradual cool down in temperatures is forecast through the period. Highs start out in the 90s on Saturday but by Monday are expected to merely top out in the 80s. We will need to monitor model trends with regards to high temperatures and moisture levels on Saturday, as our current forecast shows heat indices for some areas generally along and west of I-65 reaching at or below 105 degrees (on the cusp of Heat Advisory criteria). However, the caveat will be cloud cover and precipitation chances which may dampen the heat. Otherwise, low temperatures will follow a similar decreasing pattern, beginning in the lower to mid 70s Friday night then by Sunday night ranging in the upper 60s to around 70 degrees. && .AVIATION... (18Z TAFS) Issued at 1207 PM CDT Tue Aug 22 2023 VFR flight weather conditions are forecast through most of the period. Patchy river valley fog is possible from 09-12Z when a few locations could drop to 3-5SM (MVFR). && .HUN WATCHES/WARNINGS/ADVISORIES... AL...Heat Advisory until 8 PM CDT this evening for ALZ001>010-016. TN...Heat Advisory until 8 PM CDT this evening for TNZ076-096-097. && NEAR TERM...RAD SHORT TERM....AMP LONG TERM....26 AVIATION...17
Preliminary Local Storm Report
National Weather Service Huntsville AL
1219 PM CDT Tue Aug 22 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0500 PM Extreme Heat 3 ENE Madison 34.72N 86.70W
08/21/2023 M102 F Madison AL Broadcast Media
*** 4 INJ ***
Four high school football players
experienced heat illness during a Monday
afternoon practice. Two of the players were
taken to the hospital for treatment. The
other two were treated at the scene. None of
the injuries were life-threatening and all
have recovered.
&&The national radar mosaic for the moment the first event began.
3 heat, 2 excessive heat. Local standard time, as filed.
Heat index values reached 105 to 109 degrees during the peak heating hours, with overnight lows in the 70s.
Heat index values reached 105 to 109 degrees during the peak heating hours, with overnight lows in the 70s.
Heat index values reached 105 to 109 degrees during the peak heating hours, with overnight lows in the 70s.
The heat index peaked at 110 degrees during the mid afternoon hours.
The heat index peaked at 110 degrees during the mid afternoon hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Tennessee in 2023Every state in 2023This day in weather historyWarnings in Tennessee, August 2023
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1131933, 1131934, 1131935, 1131937, 1131940.