Excessive Heat in Texas, July 10 to 28, 2023

Name: Excessive Heat in Texas, July 10 to 28, 2023
Start: 2023-07-10T12:00
End: 2023-07-28T21:00
Location: Texas

July 10 to 28, 2023 · NWS EWX · 23 events in 23 counties and zones

Where it happened

Every event with a place to put it; 23 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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Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 23

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 EWX wrote it up.

Strong high pressure settled over South Central Texas, and temperatures soared. The heat wave started on the 10th when temperatures in Blanco, Caldwell, De Witt, Hays, Llano and Travis Counties reached 105 degrees, and the heat index in Maverick County reached 114. The heat spread from there reaching most of South Central Texas by the 12th. Widespread excessive heat continued until the 21st and then continued sporadically until the 28th. Temperatures reached 108 in Llano on the 12th, 13th, and 17th and at Austin Camp Mabry on the 12th and 17th. Heat index topped out at 117 at New Braunfels on the 11th, 115 at San Antonio Stinson on the 11th, at Gonzales on the 11th and 12th, Eagle Pass on the 11th and 12th, and Carrizo Springs on the 11th. Record high temperatures were set at Austin Bergstrom on the 13th and 18th, Austin Camp Mabry each day from the 16th through the 20th, and at San Antonio on the 12th, 14th-16th, 18th, and the 21st. Record warm low temperatures were set at Austin Camp Mabry on the 12th-15th and the 20th and at San Antonio on the 12th. This month was the warmest July on record at Austin Camp Mabry and the second warmest at San Antonio.

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 Austin/San Antonio, TX wrote its last area forecast discussion before the first event at Jul 10, 11:26 AM CST, 34 minutes earlier.

Area forecast discussion, Jul 10, 11:26 AM CST, 34 minutes before

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1226 PM CDT Mon Jul 10 2023

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 222 AM CDT Mon Jul 10 2023

Synopsis/Mesoanalysis: Early morning surface observations indicate
warm and muggy conditions areawide, with most locations reporting
temperatures in the low-mid 80s with dewpoints in the mid-70s. A
stalled outflow boundary is evident just to the north of the region,
with the latest observations showing the feature weaving east to
west along an approximate San Angelo - Waco - Nacogdoches line. The
western segment of the boundary should gradually wash out with the
onset of daytime heating this morning, though the 00Z Monday CAM
suite suggests that convection currently ongoing to the east of the
DFW Metroplex will help to reinforce its eastern periphery. This
should allow said portion of the outflow to persist into the
afternoon hours today, with scattered thunderstorm development
possible in its vicinity. A few of these storms could make into
northeast portions of the region through early evening, though they
will be quick to dissipate following sunset. The remainder of the
period will be characterized by the continued influence of
subtropical high pressure centered to our west. Widespread triple
digit high temperatures remain forecast each day, with potentially
dangerous heat indices ranging from 108-112 degrees possible over
the Winter Garden and along/east of Interstate 35. Heat safety will
therefore remain imperative for those planning to be outside for
prolonged periods of time through the duration of the short term
period.

This Afternoon: The heat will continue to be the predominant weather
headline across the region. A Heat Advisory remains in effect over
the Winter Garden, along/east of I-35, and in Llano/Burnet Counties
through 9 PM. Drink plenty of water, wear light-colored and loose-
fitting clothing, and take frequent breaks in shaded and/or air-
conditioned environments if planning to be outdoors. Those driving
are urged to never leave children and pets unattended in vehicles as
internal temperatures can reach potentially deadly levels in just
minutes. As discussed above, mentions of isolated showers and
thunderstorms have also been introduced across the northeast in the
overnight update. The latest day one severe weather outlook from the
Storm Prediction Center keeps the majority of the severe weather
risk to our north, though strong wind gusts will be possible in any
storms given deep subcloud layers featuring 30-35+ degree dew point
depressions. Activity will trend down following sunset and the loss
of daytime heating.

Tomorrow: Potentially dangerous heat will continue. While the
current Heat Advisory is set to expire at 9 PM this evening, re-
issuance for tomorrow afternoon will likely be necessary with 108-
112 degree heat indices forecast over the Winter Garden and
along/east of I-35. Said re-issuance will be coordinated with
neighboring offices later this afternoon. The current forecast
remains dry areawide, but an outside chance of an isolated storm
exists over far northeastern zones. Have drawn in an area of silent
10% PoPs to account for this potential, but have withheld any
mentions in the weather grids given low forecast confidence. The
heat will remain persistent moving into mid-late week & the long
term period, with heat safety continuing to remain essential for
those planning to be outdoors.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 222 AM CDT Mon Jul 10 2023

South Central Texas will remain under the influence of the eastern
periphery of the upper level ridge through the long-term forecast.
A weak shortwave is forecast to slide over the top and around the
eastern side of the ridge Tuesday and Tuesday night. The better
convective chances should be located across north and east Texas
Tuesday, however there could be a very slight chance of isolated
storms Tuesday afternoon through sunset Tuesday evening across
portions of Burnet, Williamson, and Lee Counties. Otherwise, hot
conditions will continue through the long term forecast. NBM dew
points continue to run too high in the afternoon, and we have
adjusted downward. Nevertheless, between air temperature in some
areas and heat index values in others, Heat Advisories will likely
continue through the week for portions of the area.

The only other thing to add is elevated fire weather conditions may
begin to develop mid to late week across the Rio Grande, southern
Edwards Plateau, and Hill Country as lower minimum RH values develop,
afternoon and evening wind speeds remain elevated, and drying of
finer fuels continues from the lack of precipitation and hot
temperatures.

&&

.AVIATION...
(18Z TAFS)
Issued at 1221 PM CDT Mon Jul 10 2023

Mostly clear skies will prevail through this evening with winds out
of the S to SSE (Se at DRT) at 7-12 kts. A quick push of the sea
breeze may lead to a brief window of ~20 kt SE gusts from 00Z-04Z.
A few clouds could develop near the I-35 terminals early tomorrow
(10-14Z) similar to today, but confidence in MVFR cigs is too low at
this time so a SCT group will continue. There is also a very low
chance for a stray shower or storm this evening at KAUS, but with a
10% or less chance there's no reason to mention even VCSH in the TAF
at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              80 104  79 103 /  10   0   0   0
Austin Bergstrom Intl Airport  79 101  77 101 /  10   0   0   0
New Braunfels Muni Airport     78 102  77 101 /   0   0   0   0
Burnet Muni Airport            79 101  78 102 /  10   0   0   0
Del Rio Intl Airport           81 104  81 104 /   0   0   0   0
Georgetown Muni Airport        79 101  78 102 /  10   0   0   0
Hondo Muni Airport             77 102  76 102 /   0   0   0   0
San Marcos Muni Airport        78 101  76 102 /   0   0   0   0
La Grange - Fayette Regional   79 100  78 100 /  10   0   0   0
San Antonio Intl Airport       79 103  79 102 /   0   0   0   0
Stinson Muni Airport           79 102  78 103 /   0   0   0   0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM CDT this evening for Burnet-Llano.

Heat Advisory until 9 PM CDT this evening for Atascosa-Bastrop-
Bexar-Caldwell-Comal-De Witt-Dimmit-Fayette-Frio-Gonzales-Guadalupe-
Hays-Karnes-Kinney-Lavaca-Lee-Maverick-Medina-Travis-Uvalde-
Williamson-Wilson-Zavala.

&&

Short-Term...Quigley
Long-Term...76
Aviation...KCW

Hazardous weather outlook, Jul 10, 2:57 AM CST, 9 hours 3 minutes before

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
357 AM CDT Mon Jul 10 2023

TXZ171>173-183>194-202>209-217>225-228-110900-
Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera-
Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde-
Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala-
Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit-
357 AM CDT Mon Jul 10 2023

This Hazardous Weather Outlook is for South-Central Texas..

.DAY ONE...Today And Tonight.

A Heat Advisory remains in effect through 9 PM this evening for
most of South Central Texas.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Elevated to potentially dangerous heat indices will continue
through the remainder of this week, with the highest values
expected in the Coastal Plains through Wednesday. Additional Heat
Advisories and/or Excessive Heat Warnings will likely be needed
over portions of the region from Tuesday forward.

Steadily decreasing relative humidities, drying vegetation, and
breezy winds could support elevated fire weather conditions over
the Rio Grande Plains, southern Edwards Plateau, and Hill Country
from Wednesday through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

The radar

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

Open the radar archive at this moment

Event by event

23 excessive heat. Local standard time, as filed.

Excessive Heat, Blanco

When: July 10, 12:00 PM CST to July 23, 9:00 PM CST
Where: Blanco forecast zone
Reported by: ASOS
Coordinates: 30.266, -98.400 (the zone’s center; the record gives no point)

Excessive Heat, Caldwell

When: July 10, 12:00 PM CST to July 22, 9:00 PM CST
Where: Caldwell forecast zone
Reported by: ASOS
Coordinates: 29.837, -97.620 (the zone’s center; the record gives no point)

Excessive Heat, De Witt

When: July 10, 12:00 PM CST to July 28, 9:00 PM CST
Where: De Witt forecast zone
Reported by: ASOS
Coordinates: 29.082, -97.357 (the zone’s center; the record gives no point)

Excessive Heat, Hays

When: July 10, 12:00 PM CST to July 22, 9:00 PM CST
Where: Hays forecast zone
Reported by: ASOS
Coordinates: 30.058, -98.031 (the zone’s center; the record gives no point)

Excessive Heat, Llano

When: July 10, 12:00 PM CST to July 25, 9:00 PM CST
Where: Llano forecast zone
Reported by: ASOS
Coordinates: 30.706, -98.684 (the zone’s center; the record gives no point)

Excessive Heat, Maverick

When: July 10, 12:00 PM CST to July 12, 9:00 PM CST
Where: Maverick forecast zone
Reported by: ASOS
Coordinates: 28.743, -100.314 (the zone’s center; the record gives no point)

Excessive Heat, Travis

When: July 10, 12:00 PM CST to July 24, 9:00 PM CST
Where: Travis forecast zone
Reported by: ASOS
Coordinates: 30.335, -97.782 (the zone’s center; the record gives no point)

Excessive Heat, Atascosa

When: July 11, 12:00 PM CST to July 23, 9:00 PM CST
Where: Atascosa forecast zone
Reported by: ASOS
Coordinates: 28.894, -98.527 (the zone’s center; the record gives no point)

Excessive Heat, Bastrop

When: July 11, 12:00 PM CST to July 12, 9:00 PM CST
Where: Bastrop forecast zone
Reported by: ASOS
Coordinates: 30.104, -97.312 (the zone’s center; the record gives no point)

Excessive Heat, Bexar

When: July 11, 12:00 PM CST to July 19, 9:00 PM CST
Where: Bexar forecast zone
Reported by: ASOS
Coordinates: 29.449, -98.520 (the zone’s center; the record gives no point)

Excessive Heat, Burnet

When: July 11, 12:00 PM CST to July 18, 9:00 PM CST
Where: Burnet forecast zone
Reported by: ASOS
Coordinates: 30.788, -98.182 (the zone’s center; the record gives no point)

Excessive Heat, Comal

When: July 11, 12:00 PM CST to July 19, 9:00 PM CST
Where: Comal forecast zone
Reported by: ASOS
Coordinates: 29.808, -98.278 (the zone’s center; the record gives no point)

Excessive Heat, Dimmit

When: July 11, 12:00 PM CST to 9:00 PM CST
Where: Dimmit forecast zone
Reported by: ASOS
Coordinates: 28.423, -99.757 (the zone’s center; the record gives no point)

Excessive Heat, Fayette

When: July 11, 12:00 PM CST to July 12, 9:00 PM CST
Where: Fayette forecast zone
Reported by: ASOS
Coordinates: 29.877, -96.920 (the zone’s center; the record gives no point)

Excessive Heat, Guadalupe

When: July 11, 12:00 PM CST to July 19, 9:00 PM CST
Where: Guadalupe forecast zone
Reported by: ASOS
Coordinates: 29.583, -97.949 (the zone’s center; the record gives no point)

Excessive Heat, Medina

When: July 11, 12:00 PM CST to July 13, 9:00 PM CST
Where: Medina forecast zone
Reported by: ASOS
Coordinates: 29.356, -99.110 (the zone’s center; the record gives no point)

Excessive Heat, Wilson

When: July 11, 12:00 PM CST to July 19, 9:00 PM CST
Where: Wilson forecast zone
Reported by: ASOS
Coordinates: 29.174, -98.087 (the zone’s center; the record gives no point)

Excessive Heat, Zavala

When: July 11, 12:00 PM CST to July 12, 9:00 PM CST
Where: Zavala forecast zone
Reported by: ASOS
Coordinates: 28.866, -99.761 (the zone’s center; the record gives no point)

Excessive Heat, Williamson

When: July 12, 12:00 PM CST to July 18, 9:00 PM CST
Where: Williamson forecast zone
Reported by: ASOS
Coordinates: 30.648, -97.601 (the zone’s center; the record gives no point)

Excessive Heat, Bandera

When: July 13, 12:00 PM CST to July 19, 9:00 PM CST
Where: Bandera forecast zone
Reported by: ASOS
Coordinates: 29.747, -99.246 (the zone’s center; the record gives no point)

Excessive Heat, Frio

When: July 13, 12:00 PM CST to July 20, 9:00 PM CST
Where: Frio forecast zone
Reported by: ASOS
Coordinates: 28.868, -99.108 (the zone’s center; the record gives no point)

Excessive Heat, Gonzales

When: July 13, 12:00 PM CST to July 19, 9:00 PM CST
Where: Gonzales forecast zone
Reported by: ASOS
Coordinates: 29.457, -97.492 (the zone’s center; the record gives no point)

Excessive Heat, Karnes

When: July 15, 12:00 PM CST to July 19, 9:00 PM CST
Where: Karnes forecast zone
Reported by: ASOS
Coordinates: 28.906, -97.859 (the zone’s center; the record gives no point)

What these are

Excessive Heat: Heat at or above the local excessive heat warning criteria, or heat that caused deaths.

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

The same day elsewhere

Every storm in Texas in 2023 Every state in 2023 This day in weather history Warnings in Texas, July 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: 1122247, 1122319, 1122320, 1122321, 1122324, 1122325, 1122326, 1122242, 1122341, 1122342, 1122343, 1122344, 1122345, 1122346, 1122349, 1122351, 1122353, 1122354, 1122352, 1122340, 1122347, 1122348, 1122350.