Excessive Heat and Heat in Arkansas, August 2 to 5, 2023

Name: Excessive Heat and Heat in Arkansas, August 2 to 5, 2023
Start: 2023-08-02T12:00
End: 2023-08-05T18:00
Location: Arkansas

August 2 to 5, 2023 · NWS MEG · 22 events in 10 counties and zones

The strong upper ridge of high pressure that dominated the weather across the southwest US during the summer of 2023 bulged east into the Mid-South at times during the month of August. High temperatures combined with high humidity produced heat index values over 105 degrees and in some cases over 110 degrees.

Where it happened

Every event with a place to put it; 22 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 22

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.

What happened

The episode as NWS MEG wrote it up.

What forecasters said that day

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 Memphis, TN wrote its last area forecast discussion before the first event at Aug 2, 11:30 AM CST, 30 minutes earlier.

Area forecast discussion, Aug 2, 11:30 AM CST, 30 minutes before

Area Forecast Discussion
National Weather Service Memphis TN
1230 PM CDT Wed Aug 2 2023

...New AVIATION...

.UPDATE...Issued at 1040 AM CDT Wed Aug 2 2023

A decaying MCS is moving across the Tennessee River. Clouds and
precipitation from this system is helping to keep temperatures a
bit cooler than expected. As a result, we may struggle to reach
heat advisory criteria(at or above 105 heat indices) for portions
of east Arkansas, Shelby county, TN and northwest Mississippi.
The delta counties south of Memphis have seen less cloud cover and
still stand the best chance of seeing advisory or even excessive
heat warning(at or above 110 heat indices). Another MCS may take
a similar track overnight, but latest guidance suggests it will
track slightly farther east limiting the impact to west Tennessee.
A ridge is expected to strengthen over the lower Mississippi
River Valley over the next 24 hours resulting in another hot day
tomorrow. A heat advisory and excessive heat warning has been
issued for generally the western two-thirds of the Midsouth.
Temperatures are expected to trend slightly cooler Friday into the
weekend.

30/Sirmon

&&

.SYNOPSIS...
Issued at 445 AM CDT Wed Aug 2 2023

A series of shortwave upper level troughs will bring chances for
showers and thunderstorms to areas east of the Mississippi River
into Thursday. Very hot temperatures in the 90s are expected to
build into the Mid-South with heat index values rising to between
105 to 109 degrees this afternoon and reaching or exceeding 109
degrees across many locations along and west of the Mississippi
River on Thursday. These hot temperatures may persist across
portions of the area into early this weekend. Shower and
thunderstorm chances will increase this weekend as a ridge of high
pressure retrogrades west and a cold front moves through the area
late this weekend into early next week. This front is anticipated
to bring cooler air back into the region.

&&

.DISCUSSION...
(Today through Tuesday)
Issued at 445 AM CDT Wed Aug 2 2023

GOES-16 Satellite trends place an upper-level trough axis along
both coasts of the Continental United States, and an upper-level
ridge over the Southern Plains. Monsoonal moisture is being
advected from the Southwest United States into the Central Plains
and Middle Mississippi Valley. A Mesoscale Convective System
developed over north central Missouri early this morning in
association with a 850 mb nocturnal low level jet. As a result,
showers and thunderstorms developed over north central Missouri
and have since then expanded into central and east central
Missouri. A few mid/high level clouds are moving across the Mid-
South with temperatures as of 3 AM CDT in the lower to middle 70s
across most locations.

Short-term models including Convective Allowing Model solutions
indicate the aforementioned upstream showers and thunderstorms
will spread into southeast Missouri and western Kentucky this
morning. This activity is expected to weaken and perhaps reach
areas north of I-40 in West Tennessee this morning.

Otherwise, temperatures are expected to increase today in the
middle 90s mainly south of I-40 in east Arkansas, north
Mississippi and southwest Tennessee. These hot temperatures
combined with increasing surface dewpoints will result in heat
index values approaching or exceeding 105 degrees generally along
and west of I-55, and a few locations in northwest Mississippi
seeing heat index values reach 109 degrees. As a result, the Heat
Advisory for this afternoon was expanded into portions of
northeast Arkansas, southwest Tennessee, and northwest
Mississippi, and areas along and south of a line from West Helena
to Clarksdale, Charleston Mississippi upgraded into an Excessive
Heat Warning.

Models indicate another MCS may develop upstream over the Middle
Mississippi Valley tonight and spread south into portions of the
Lower Mississippi and Tennessee Valleys late tonight into Thursday
morning. Sufficient shear will be present but weak mid-level
lapse rates and marginal elevated instability should minimize any
strong to severe thunderstorm potential overnight. Increasing
surface-based instability on Thursday combined with sufficient
shear and left over outflow boundaries may serve to produce a few
strong to severe thunderstorms generally towards the Tennessee
River in West Tennessee and northeast Mississippi. Damaging winds
will be the primary threat if any thunderstorms become severe.
06Z model guidance is trending a bit north and east of the
forecast area and pops may need to be adjusted accordingly if 12Z
guidance continues this trend.

A warm front will push northeast through the Mid-South on
Thursday. This will help to expand the very hot temperatures
across a greater portion of the area. These very hot temperatures
combined with pooling surface dewpoints will create dangerous heat
index values approaching or exceeding 109 degrees in many spots.
Consequently, this has necessitated the issuance of an Excessive
Heat Warning for areas along and west of the Mississippi River for
Thursday with a Heat Advisory bordering the warning in
coordination with neighboring offices. Later shifts will continue
to monitor short term heat trends for further expansion east if
less convection is realized than currently forecast.

Mid and long-range models suggest the upper-level ridge will
retrograde this weekend with a cold front coming through the area
late this upcoming weekend into early next week. Relatively weak
shear on the order of 20-25 kts suggests pulse type or quasi
unorganized multicell thunderstorm potential will be best
maximized during afternoon peak heating each day. Cooler
temperatures are expected behind this front for next week.

CJC

&&

.AVIATION...
(18Z TAFS)
Issued at 1211 PM CDT Wed Aug 2 2023

Lingering showers from this morning's MCS are currently affecting
MKL, however, showers should be out of the vicinity by 18z.
Another MCS expected to track through the northeastern portion of
the Mid-South tomorrow morning. Latest CAMs show this MCS only
affecting MKL tomorrow morning through early afternoon, thus
warranting VCSH. JBR could be affected tomorrow morning as well,
but confidence is currently too low to include VCSH in TAF. Winds
are predominately south/southwest through the period. Expect winds
to diminish below 5kts overnight, picking up to 9-11kts by
tomorrow morning. MEM may gust to around 20kts tomorrow afternoon
through early evening.

AEH

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
     ARZ009-018-026>028-035-036-048-049-058.

     Heat Advisory until 8 PM CDT this evening for ARZ018-026-027-035-
     036-048-049.

     Excessive Heat Warning until 8 PM CDT this evening for ARZ058.

MO...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
     MOZ113-115.

MS...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
     MSZ001-007-008-010>012-020.

     Heat Advisory until 8 PM CDT this evening for MSZ001-007-008-012-
     021.

     Excessive Heat Warning until 8 PM CDT this evening for MSZ010-
     011-020.

     Heat Advisory from 11 AM to 8 PM CDT Thursday for MSZ002-013-021-
     022.

TN...Excessive Heat Warning from 11 AM to 8 PM CDT Thursday for
     TNZ048-049-088.

     Heat Advisory until 8 PM CDT this evening for TNZ088.

     Heat Advisory from 11 AM to 8 PM CDT Thursday for TNZ001-019-050-
     051-089.

&&

PUBLIC FORECAST...JDS
AVIATION...AEH

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

12 excessive heat, 10 heat. Local standard time, as filed.

Excessive Heat, Phillips

When: August 2, 12:00 PM CST to 7:00 PM CST
Where: Phillips forecast zone
Reported by: AWOS
Coordinates: 34.428, -90.848 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Heat, Lee

When: August 2, 12:00 PM CST to 7:00 PM CST
Where: Lee forecast zone
Reported by: AWOS
Coordinates: 34.781, -90.782 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Excessive Heat, Cross

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Cross forecast zone
Reported by: AWOS
Coordinates: 35.296, -90.771 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, St. Francis

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: St. Francis forecast zone
Reported by: AWOS
Coordinates: 35.022, -90.748 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Lee

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Lee forecast zone
Reported by: AWOS
Coordinates: 34.781, -90.782 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Phillips

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Phillips forecast zone
Reported by: AWOS
Coordinates: 34.428, -90.848 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Heat, Clay

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Clay forecast zone
Reported by: AWOS
Coordinates: 36.368, -90.417 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Greene

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Greene forecast zone
Reported by: AWOS
Coordinates: 36.118, -90.559 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Craighead

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Craighead forecast zone
Reported by: ASOS
Coordinates: 35.831, -90.633 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Mississippi

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Mississippi forecast zone
Reported by: ASOS
Coordinates: 35.764, -90.054 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Poinsett

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Poinsett forecast zone
Reported by: ASOS
Coordinates: 35.574, -90.663 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Crittenden

When: August 3, 10:00 AM CST to 7:00 PM CST
Where: Crittenden forecast zone
Reported by: ASOS
Coordinates: 35.208, -90.309 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Excessive Heat, Craighead

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Craighead forecast zone
Reported by: ASOS
Coordinates: 35.831, -90.633 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Poinsett

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Poinsett forecast zone
Reported by: ASOS
Coordinates: 35.574, -90.663 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Crittenden

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Crittenden forecast zone
Reported by: ASOS
Coordinates: 35.208, -90.309 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Cross

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Cross forecast zone
Reported by: ASOS
Coordinates: 35.296, -90.771 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, St. Francis

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: St. Francis forecast zone
Reported by: AWOS
Coordinates: 35.022, -90.748 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Lee

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Lee forecast zone
Reported by: AWOS
Coordinates: 34.781, -90.782 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Excessive Heat, Phillips

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Phillips forecast zone
Reported by: AWOS
Coordinates: 34.428, -90.848 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 110 degrees.

Heat, Clay

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Clay forecast zone
Reported by: AWOS
Coordinates: 36.368, -90.417 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Greene

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Greene forecast zone
Reported by: AWOS
Coordinates: 36.118, -90.559 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

Heat, Mississippi

When: August 5, 10:00 AM CST to 6:00 PM CST
Where: Mississippi forecast zone
Reported by: AWOS
Coordinates: 35.764, -90.054 (the zone’s center; the record gives no point)

Heat index values reached or exceeded 105 degrees.

What these are

Excessive Heat: Heat at or above the local excessive heat warning criteria, or heat that caused deaths.
Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Arkansas in 2023 Every state in 2023 This day in weather history Warnings in Arkansas, August 2023

Sources

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: 1133881, 1133885, 1133889, 1133890, 1133891, 1133892, 1133900, 1133901, 1133902, 1133903, 1133904, 1133905, 1133920, 1133921, 1133922, 1133923, 1133924, 1133925, 1133926, 1133927, 1133928, 1133929.