An expansive ridge sat over the southern portion of the CONUS. This ridge caused extreme record-breaking temperatures across much of the south, including southeast Louisiana and southern Mississippi.
Every event with a place to put it; 28 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 LIX wrote it up.
An expansive ridge sat over the southern portion of the CONUS. This ridge caused extreme record-breaking temperatures across much of the south, including southeast Louisiana and southern Mississippi. The record-breaking temperatures paired with high humidity values caused the heat to be excessive across southeast Louisiana and southern Mississippi.
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 New Orleans, LA wrote its last area forecast discussion before the first event at Aug 5, 2:21 AM CST, 7 hours 39 minutes earlier.
Area Forecast Discussion
National Weather Service New Orleans LA
321 AM CDT Sat Aug 5 2023
...New SHORT TERM, LONG TERM, AVIATION, MARINE...
.SHORT TERM...
(Today through Sunday)
Issued at 313 AM CDT Sat Aug 5 2023
Wow is what comes to mind as all sites are breaking records and
continue moving through the hottest conditions seen in this area in
many years. Most stations were hitting the upper 90s to around 100
yesterday, even Lakefront Arpt reached 97F. SST along the coast are
running in the lower 90s, so even the water does not provide any
relief. At this point, even some cloud cover would be fantastic.
Unfortunately, this bake-a-thon will continue for the next several
days. The heat warning will remain for today and another heat watch
will be provided with this package for Sunday. If you have lived in
the southeastern US long enough, you find a love/hate relationship
with these heat waves. One hates the heat, but the thing causing the
heat(stacked high) keeps the summer Rougarou(hurricanes) away from
the area. These heat waves are normal for this time of year, just
not this intense. And when they break, it normally means the stacked
ridge has either weakened or moved back west which opens the gulf up
for business and we move back into a more normal temp/moisture
regime as the deep easterlies invade the area and our storms start
coming from the E and SE instead of from the north. There will be
more on this in the extended as there is some evidence that this
very thing may be coming.
&&
.LONG TERM...
(Sunday night through Friday)
Issued at 313 AM CDT Sat Aug 5 2023
Temps will continue to climb into the upper 90s to around 100 at
least during the first part of the new week. And it looks as if BTR
will tie their 100F duration record today and break it Sunday. There
could be a few more days tacked onto this record as well. Other
sites will be very close if not breaking their record highs as well.
The NBM deterministic is very near the NBM75 percentile. But running
hot is what it should be doing, but it may be a few degrees too
warm. Have backed off one or two degrees for a few sites but for the
most part this is not a big issue as temps will still be too hot to
achieve a lot of outdoor work. The upper troughing between the two
stacked high pressure regions, one over our area and the other now
starting to move into the SW CONUS, will slowly bring a cold front
farther east and SE. No, this front does not reach us, it stalls
over the AR/LA border. But it will force the current upper part of
the stacked high over us to the south and weaken it. This is more
due to the very strong Pacific stacked high building back into the
SW CONUS, which forces the trough east and hence the upper high over
us to the south since it can't move into the Bermuda High. The upper
level pattern may become more trough like but the mid and low level
high is not going anywhere too fast, so the heat will continue with
a degree or two shaved off current daily highs by mid week. Don't
get too excited just yet as highs will still remain in the mid to
upper 90s with a 100F thrown in for good measure. But this will be
the start of the end of this heat regime as this high does not get
stacked throughout the column again. The mid to low level high over
the area exits stage right by mid week and becomes an extention of
the Bermuda High. Then, you guessed it, the SW CONUS upper
anticyclone just can't stay home and moves to the Rio Grande valley
by mid week as well. Our area will remain under a more troughy upper
level synoptic pattern and the mid levels begin to join along by the
end of the week. Another front will move into the Texarkana region
and stall providing another interface for storm systems to ride
along. But this time the high has been weakened by repeated advances
of the troughing that one final MCS feature develops along this
frontal boundary and rushes SE away from it by Friday into Saturday.
This occurs as a strong upper low traverses the southern gulf
forcing the Rio Grande high back west. It will be noticeable by next
weekend when this occurs as the area comes under deeper troughing
and easterlies bringing deeper tropical moisture to the area and the
air becomes more breathable. Yes, this does open the gulf up for
business, but we can't have it both ways, seems there's some kind of
cake theme with this saying. Anyway, at least one easterly wave
moves through the gulf by the start of next week and since the
strong high is not in place, it does not get flattened or pressed
south which means it could bring a few days of much needed rainfall
to the area possibly by Sunday or Monday of next week. I know this
is a reach(far beyond this fcasts temporal params), but one thing is
certain, this heat wave will eventually break and this is a very
normal climo way for it to break, so it does make sense.
&&
.AVIATION...
(06Z TAFS)
Issued at 313 AM CDT Sat Aug 5 2023
VFR conditions across all terminals, and that should predominate
through this forecast. There will be a better chance of TSRA for
terminals on the Miss gulf coast late this afternoon. If these
storms do occur, the outflow from them could be strong from the
direction of the storm itself. Anthing that develops should
dissipate shortly after sunset.
&&
.MARINE...
Issued at 313 AM CDT Sat Aug 5 2023
Surface high pressure remains into the start of the new week. This
bodes well for marine conditions in most areas with winds peaking
around 10kt, but generally closer to 5kt. Diurnal convection is not
likely until late in this fcast, but also not out of the question
and in the vicinity of any storms the winds could be higher. The
diurnal jet that develops mainly across the sounds will be the only
areas that peak around 15kt during the predawn morning hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 99 75 99 75 / 10 10 10 0
BTR 101 81 101 81 / 10 0 10 0
ASD 100 80 99 80 / 10 10 20 0
MSY 100 82 100 82 / 10 0 20 0
GPT 99 81 97 81 / 30 10 20 10
PQL 99 79 97 79 / 30 10 30 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Excessive Heat Warning from 11 AM this morning to 7 PM CDT this
evening for LAZ034>037-039-046>048-056>060-064>071-076>090.
Excessive Heat Watch from Sunday morning through Sunday evening
for LAZ034>037-039-046>048-056>060-064>071-076>090.
GM...None.
MS...Excessive Heat Warning from 11 AM this morning to 7 PM CDT this
evening for MSZ068>071-077-083>088.
Excessive Heat Watch from Sunday morning through Sunday evening
for MSZ068>071-077-083>088.
GM...None.
&&
SHORT TERM...TE
LONG TERM....TE
AVIATION...TE
MARINE...TEThe national radar mosaic for the moment the first event began.
36 excessive heat. Local standard time, as filed.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
Very hot and humid weather occurred for all of southeast Louisiana on August 5th. High temperatures were in the upper 90s to 100 degrees with heat indices were in the 113 to 115 degree range each afternoon.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Louisiana in 2023Every state in 2023This day in weather historyWarnings in Louisiana, 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: 1137449, 1137450, 1137451, 1137452, 1137453, 1137454, 1137455, 1137456, 1137457, 1137458, 1137459, 1137460, 1137461, 1137462, 1137463, 1137464, 1137465, 1137466, 1137467, 1137468, 1137469, 1137471, 1137472, 1137473, 1137474, 1137475, 1137476, 1137477, 1137478, 1137480, 1137481, 1137482, 1137483, 1137484, 1137485, 1137486.