Excessive Heat and Heat in Texas, May 7 to 9, 2024

Name: Excessive Heat and Heat in Texas, May 7 to 9, 2024
Start: 2024-05-07T14:30
End: 2024-05-09T18:53
Location: Texas

May 7 to 9, 2024 · NWS BRO · 19 events in 10 counties and zones

Where it happened

Every event with a place to put it; 19 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: 19

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 BRO wrote it up.

An unseasonably strong sub-tropical ridge/heat dome centered over central and southern Mexico strengthened and shifted northward towards the Rio Grande Valley/Deep South Texas region. Temperatures at around 5,000 feet above the ground soared to 78 to 86 degrees Fahrenheit over the local area. This translated to surface temperatures rising into the upper 90s to mid 100s from May 7-9. Combined with dewpoint temperatures in the 70s to around 80, this produced apparent, or feels-like temperatures, between 111-116F across locations along and east of IH-69C/US 281 from Brooks/Hidalgo County into Cameron, Willacy, and Kenedy County. The hottest temperatures were located from the mid-lower Rio Grande Valley northward along I-69E and I-69C, peaking on May 9th.

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 Brownsville, TX wrote its last area forecast discussion before the first event at May 7, 1:46 PM CST, 44 minutes earlier.

Area forecast discussion, May 7, 1:46 PM CST, 44 minutes before

Area Forecast Discussion
National Weather Service Brownsville TX
246 PM CDT Tue May 7 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Tonight through Wednesday night)
Issued at 243 PM CDT Tue May 7 2024

Key Message:

- Hot and unseasonably warm temperature are expected through
the short term.

-A Heat Advisory is in effect Wednesday afternoon from 1 PM to 7 PM
for inland, Cameron, inland Willacy, inland Kenedy, Hidalgo and
Brooks counties.

-Moderate risk of rip currents through Wednesday.

Zonal to slightly southwesterly flow aloft over the short term
period will lead to abnormally warm temperatures, heat indices in
the triple digits and dry conditions. At the surface, high pressure
over the eastern Gulf of Mexico will continue to provide southerly
flow. Low pressure across the Sierra Madre will lead to an increased
pressure gradient and slightly increased winds along the coast east
afternoon. We continue to see abundant cloud cover today, but as we
head into later this afternoon we should see a bit more clearing in
the afternoon.

Lets talk heat. Temperatures this afternoon will be well above
normal but thanks to lingering cloudcover, heat indices will likely
remain just shy of Heat Advisory criteria. For Wednesday,
temperatures are expected to be warmer with highs rising into the
90s and low triple digits across the region. Heat indices will rise
to between 104 degrees and 113 degrees across the entire CWA away
from the Island with the highest heat indices along the I-69C
corridor. A Heat Advisory has been issued for inland Cameron, inland
Willacy, inland Kenedy, Brooks, and Hidalgo counties with heat
indices between 111 degrees and 113 degrees Wednesday afternoon.
Overnight temperatures will be warm with lows in the mid to upper
70s.

&&

.LONG TERM...
(Thursday through next Tuesday)
Issued at 243 PM CDT Tue May 7 2024

Hot temperatures will continue to be the main concern for the
start of the long term period. As the dryline over Central Texas
shifts further east Thursday temperatures will again rise into the
triple digits. Higher dewpoints east of the dryline will likely
support heat indices in the 111-115 range roughly along and east
of I-69C Thursday afternoon.

A passing upper level shortwave looks to support the passage of a
cold front Thursday night into Friday. This will likely bring
more seasonal temperatures for the weekend, with afternoon highs
in the upper 80s to low 90s. Easterly to southeasterly surface
winds look to return by Sunday, bringing a slight increase in
temperatures and moisture.

Rain chances look to remain fairly low through the period, however
increased forcing and ample instability could support a slight
chance for showers and thunderstorms along the cold front Friday.
Additional rain chances look possible through the day Saturday as
weak overrunning looks to setup behind the front. With the return
of easterly to southeasterly surface winds Sunday, increased
moisture and instability could again support a slight chance of
showers and thunderstorms. The best chance for rain looks to be
Sunday, with PoPs around 20-30%.

&&

.AVIATION...
(18Z TAFS)
Issued at 1215 PM CDT Tue May 7 2024

MVFR ceilings should lift to VFR this afternoon across all
aerodromes. This evening, however, ceilings will lower again
thanks to the abundant moisture in the low levels of the
atmosphere and MVFR ceilings are expected. As we head into late
tonight/early Wednesday morning, hazy conditions may develop along
with IFR conditions.

&&

.MARINE...
Issued at 243 PM CDT Tue May 7 2024

Tonight through Wednesday night...Light to moderate southeast winds
and moderate seas will prevail through the forecast period.
Tonight, we could see some patchy fog/hazy conditions on the Gulf
waters. Brief periods of Small Craft Exercise Caution conditions
will be possible each afternoon, especially across the Laguna
Madre and northern Gulf waters due to elevated winds.

Thursday through next Tuesday...Light to moderate winds and
moderate seas are likely Thursday. However, stronger northeasterly
winds behind a cold front Friday will likely require Small Craft
Exercise Caution headlines or Small Craft Advisories Friday
afternoon. Wind speeds look to diminish Friday night, with light
to moderate winds and moderate seas continuing through the
remainder of the period.

&&

.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE             78  94  78 101 /   0   0   0   0
HARLINGEN               76  99  76 104 /   0   0   0   0
MCALLEN                 78 102  77 105 /   0   0   0   0
RIO GRANDE CITY         76 105  76 107 /   0   0   0   0
SOUTH PADRE ISLAND      77  84  78  88 /   0   0   0   0
BAYVIEW/PORT ISABEL     77  93  76  98 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory from 1 PM to 7 PM CDT Wednesday for TXZ250-251-
     253>255-353.

GM...None.
&&

SHORT TERM...68-McGinnis
LONG TERM....60-BE
AVIATION...68

The radar

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

Open the radar archive at this moment

Event by event

13 heat, 6 excessive heat. Local standard time, as filed.

Heat, Southern Hidalgo County

When: May 7, 2:30 PM CST to 4:40 PM CST
Where: Southern Hidalgo County forecast zone
Reported by: ASOS
Coordinates: 26.397, -98.181 (the zone’s center; the record gives no point)

McAllen International Airport (KMFE) recorded max heat indices between 111-114F for a couple of hours, from 3:30-5:40 PM CDT on May 7, 2024. Values peaked at 114F at 353 PM CST. The South Texas International Airport (11 miles north of Edinburg) along the edge of southern and northern Hidalgo County reached 112F at 335 PM CST.

Heat, Northern Hidalgo County

When: May 8, 11:46 AM CST to 5:46 PM CST
Where: Northern Hidalgo County forecast zone
Reported by: RAWS
Coordinates: 26.397, -98.181 (the zone’s center; the record gives no point)

Linn-San Manuel Remote Automated Weather System (RAWS) recorded max heat indices between 111-115F for up to 6 hours, from 12:46-6:46 PM CDT on May 8, 2024. The South Texas International Airport (KEBG) Automated Weather Observing Station along the edge of northern and southern Hidalgo County peaked at 117F at 215 PM, with 111F+ values generally from 1235 through 555 PM.

Heat, Jim Hogg

When: May 8, 12:00 PM CST to 6:00 PM CST
Where: Jim Hogg forecast zone
Reported by: Mesonet
Coordinates: 27.043, -98.697 (the zone’s center; the record gives no point)

Rancho Los Comitos (Texas Mesonet) recorded max heat indices between 111-115F for 3 hours, from 3:00-6:00 PM CDT (2 to 5 PM CST) on May 8, 2024. By proxy, southern Jim Hogg County (less than 10 miles north of this location) can be assumed to have observed similar values during this time.

Heat, Starr

When: May 8, 1:11 PM CST to 5:11 PM CST
Where: Starr forecast zone
Reported by: Mesonet
Coordinates: 26.562, -98.738 (the zone’s center; the record gives no point)

La Puerta Remote Automated Weather Sensor (RAWS) 5.65 miles east of Rio Grande City recorded max heat indices between 111-117F for 4 hours, from 2:11-6:11 PM CDT on May 8, 2024. Rancho Los Comitos (Texas Mesonet) recorded max heat indices between 111-115F for 3 hours, from 3:00-6:00 PM CDT on May 8, 2024. Note that the La Puerta location runs a bit higher, so proxy values may be closer to 111-113 nearby.

Heat, Cameron

When: May 8, 1:15 PM CST to 5:20 PM CST
Where: Cameron forecast zone
Reported by: ASOS
Coordinates: 26.152, -97.453 (the zone’s center; the record gives no point)

Brownsville/South Padre Island International Airport (KBRO) recorded max heat indices between 111-116F 1.5 hours, from 2:15-3:55 PM CDT on May 8, 2024. Harlingen Valley International Airport (KHRL) recorded max heat indices between 111-118F for 3.5 hours, from 2:52-6:20 PM CDT on May 8, 2024.

Heat, Willacy

When: May 8, 1:30 PM CST to 5:00 PM CST
Where: Willacy forecast zone
Reported by: ASOS
Coordinates: 26.477, -97.592 (the zone’s center; the record gives no point)

Harlingen Valley International Airport (KHRL) recorded max heat indices between 111-118F for 3.5 hours, from 2:52-6:20 PM CDT on May 8, 2024. The Sarita Mesonet station in Kenedy County recorded peak heat index values between 111 and 115F between 2 and 430 PM CST. By proxy, Willacy County likely had similar heat index values (111 to 116) between 1 PM and 5 PM CST.

Excessive Heat, Southern Hidalgo County

When: May 8, 1:30 PM CST to 6:30 PM CST
Where: Southern Hidalgo County forecast zone
Reported by: ASOS
Coordinates: 26.397, -98.181 (the zone’s center; the record gives no point)

Peak Heat Index reached 116F at McAllen/Miller Airport at around 130 PM CST and continue through around 630 PM CST on May 8th, peaking at 121F at 353 PM CST. Nearby Lower Rio Grande Valley Wildlife Refuge Remote Automated Weather Sensor (RAWS) along the Rio Grande southeast of Pharr recorded more than 123F, but this value is likely a high bias. Still, it was likely that realistic values of 116 to 120 occurred in much of southern Hidalgo County. Dangerous heat index values of 111 began at 1240 PM CST and continued through 710 PM CST.

Heat, Inland Kenedy County

When: May 8, 2:00 PM CST to 4:30 PM CST
Where: Inland Kenedy County forecast zone
Reported by: Mesonet
Coordinates: 26.928, -97.636 (the zone’s center; the record gives no point)

The Texas Mesonet site at Sarita recorded two and a half hours of heat index between 111 and 115F, peaking at 115F at around 230 PM CST.

Heat, Brooks

When: May 8, 2:15 PM CST to 6:35 PM CST
Where: Brooks forecast zone
Reported by: AWOS
Coordinates: 27.032, -98.219 (the zone’s center; the record gives no point)

Falfurrias (AWOS) recorded max heat indices between 111-117F for about 4.5 hours, from 3:15-7:35 PM CDT on May 8, 2024.

Heat, Coastal Cameron

When: May 9, 10:53 AM CST to 3:30 PM CST
Where: Coastal Cameron forecast zone
Reported by: ASOS
Coordinates: 26.152, -97.453 (the zone’s center; the record gives no point)

Heat, Coastal Willacy

When: May 9, 10:53 AM CST to 3:30 PM CST
Where: Coastal Willacy forecast zone
Reported by: ASOS
Coordinates: 26.477, -97.592 (the zone’s center; the record gives no point)

The Cameron County Airport Automated Surface Observing Sensor near Bayview recorded around 4.5 hours of heat index values between 111 and 115F between 1153 AM CDT and 430 PM CDT. Peak values of 115 occurred between 253 and 353 PM. By proxy, it can be interpolated that Coastal Willacy also observed similar heat index values during the same time.

Excessive Heat, Cameron

When: May 9, 11:53 AM CST to 3:53 PM CST
Where: Cameron forecast zone
Reported by: ASOS
Coordinates: 26.152, -97.453 (the zone’s center; the record gives no point)

Brownsville/South Padre Island International Airport (KBRO) recorded heat indices between 118-125F for 4 hours, from 12:53-4:53 PM CDT (1153 to 353 CST) on May 9, 2024. Peak value was 125F at 253 PM, a May record and near the all-time record since hourly data have been available. Between the hours of 10:53 AM (953 AM to 510 PM CDT) to 6:10 PM CDT (about 7.5 hours), heat indices were at least 111F. Harlingen Valley International Airport (KHRL) recorded heat indices between 117-125F for 4 hours, from 1:52-5:52 PM CDT (1252 to 452 CST). The value of 125F was a May record, and rivaled all-time hourly records. Between the hours of 11:52 AM to 6:52 PM CDT (7 hours), heat indices were at least 111F.

Ambient temperatures set daily and monthly records for May 9th. There were no known direct fatalities, though hospitalizations for heat-related illnesses increased by an unknown number on this day.

Excessive Heat, Willacy

When: May 9, 12:00 PM CST to 4:00 PM CST
Where: Willacy forecast zone
Reported by: ASOS
Coordinates: 26.477, -97.592 (the zone’s center; the record gives no point)

Harlingen Valley International Airport (KHRL) recorded heat indices between 117-125F for 4 hours, from 1:52-5:52 PM CDT (1252 to 452 CST). The value of 125F was a May record, and rivaled all-time hourly records. Between the hours of 11:52 AM to 6:52 PM CDT (7 hours), heat indices were at least 111F. Ambient temperatures set daily and monthly records for May 9th. By proxy, it can be interpolated that at least southern inland Willacy County had similar heat index values, with slightly lower values farther north. There were no known direct fatalities, though hospitalizations for heat-related illnesses increased by an unknown number on this day.

Heat, Jim Hogg

When: May 9, 12:00 PM CST to 4:00 PM CST
Where: Jim Hogg forecast zone
Reported by: Mesonet
Coordinates: 27.043, -98.697 (the zone’s center; the record gives no point)

Ranchos Los Comitos (Texas Mesonet) recorded peak heat indices between 111-115F for 3 hours, from 1:55-4:55 PM CDT. By proxy, southern Jim Hogg County likely observed the same values around the same time. Farther north, the Hebbronville Automated Weather Observing System recorded a peak heat index of 110F at 530 PM CDT, and the Hellen Station Mesonet reached 111 to 113F intermittently short between 4 and 6 PM CDT.

Heat, Inland Kenedy County

When: May 9, 12:15 PM CST to 4:30 PM CST
Where: Inland Kenedy County forecast zone
Reported by: Mesonet
Coordinates: 26.928, -97.636 (the zone’s center; the record gives no point)

The Texas Mesonet site at Sarita recorded heat index values between 111 and 114 from 115 through 530 PM. Similar values likely occurred farther south in the county.

Excessive Heat, Northern Hidalgo County

When: May 9, 12:46 PM CST to 5:46 PM CST
Where: Northern Hidalgo County forecast zone
Reported by: AWOS
Coordinates: 26.397, -98.181 (the zone’s center; the record gives no point)

Linn-San Manuel (Remote Automated Weather Sensor) recorded heat indices between 116-122F for 6 hours, from 12:46-6:46 PM CDT (1146-546 PM CST) on May 9, 2024. Between the hours of 11:46 AM to 7:46 PM CDT (1046 AM to 656 PM CST) (8 hours), heat indices were at least 111F. The South Texas International Airport (north of Edinburg) recorded heat indices between 117-123F for 4 hours, from 1:55-5:55 PM CDT (1255 to 455 PM CST) on May 9, 2024. Between the hours of 1:55 PM to 7:55 PM CDT (1255 to 655 CST; 6 hours), heat indices were at least 111F.

As of this writing, there were no known fatalities from these near-record heat index values (annual), but hospitalizations increased compared with average in the McAllen/Mission area due to heat-related illnesses.

Excessive Heat, Southern Hidalgo County

When: May 9, 12:53 PM CST to 6:53 PM CST
Where: Southern Hidalgo County forecast zone
Reported by: ASOS
Coordinates: 26.397, -98.181 (the zone’s center; the record gives no point)

McAllen International Airport (KMFE) recorded heat indices between 117 and at least 122F for 7 hours, from 12:53-7:53 PM CDT on May 9, 2024. Peak value of 122F (hourly) was reached at 453 CDT. Between the hours of 11:53 AM to 8:35 PM CDT (9 hours), heat indices were at least 111F. Weslaco Mid Valley Airport (AWOS) recorded heat indices between 116-122F for 3 hours, from 3:55-6:55 PM CDT on May 9, 2024. Between the hours of 12:55 PM to 7:35 PM CDT (6.5 hours), heat indices were at least 111F. Peak value of 122 occurred at 635 PM CDT. Other observing locations (Mesonet, Remote Automated Weather Station) recorded similar values.

As of this writing, there were no known direct fatalities from the heat, but there was an unknown increase in hospitalizations compared with other times in early May.

Heat, Starr

When: May 9, 12:55 PM CST to 3:55 PM CST
Where: Starr forecast zone
Reported by: Mesonet
Coordinates: 26.562, -98.738 (the zone’s center; the record gives no point)

Ranchos Los Comitos (Texas Mesonet) recorded peak heat indices between 111-115F for 3 hours, from 1:55-4:55 PM CDT. La Puerta (Remote Automated Weather Station) recorded peak heat indices between 111-118F for 6 hours, from 12:11-6:11 PM CDT. Note that the La Puerta site, 5.65 miles east of Rio Grande City, tends to run a bit high on temperature and humidity.

Excessive Heat, Brooks

When: May 9, 2:35 PM CST to 5:55 PM CST
Where: Brooks forecast zone
Reported by: AWOS
Coordinates: 27.032, -98.219 (the zone’s center; the record gives no point)

Falfurrias Airport (AWOS) recorded heat indices between 116-123F for 3.5 hours, from 3:35-6:55 PM CDT on May 9, 2024. Between the hours of 1:35-7:35 PM CDT (6 hours), heat indices were at least 111F.

What these are

Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.
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 2024 Every state in 2024 This day in weather history Warnings in Texas, May 2024

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: 1166102, 1166430, 1166431, 1166427, 1166416, 1166433, 1188859, 1166432, 1166428, 1188895, 1188896, 1166448, 1166636, 1166637, 1188897, 1166522, 1166452, 1166639, 1188892.