A stout mid level ridge built over Deep South Texas during the last few days of August, allowing high temperatures to climb. These high temperatures combined with high surface relative humidity, allowed afternoon heat indices to climb to a dangerous 111 degrees or greater for a couple of hours in the afternoons of August 30th and 31st in populated areas along the Rio Grande.
Every event with a place to put it; 4 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 BRO wrote it up.
A stout mid level ridge built over Deep South Texas during the last few days of August, allowing high temperatures to climb. These high temperatures combined with high surface relative humidity, allowed afternoon heat indices to climb to a dangerous 111 degrees or greater for a couple of hours in the afternoons of August 30th and 31st in populated areas along the Rio Grande.
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 Aug 28, 1:43 PM CST, 7 minutes earlier.
Area Forecast Discussion
National Weather Service Brownsville TX
Issued by National Weather Service Austin/San Antonio TX
243 PM CDT Fri Aug 28 2020
.SHORT TERM (Tonight through Saturday Night):
Skies are mostly sunny this afternoon with only a handful of fair
weather cumulus clouds around across Deep South Texas. The story
of today and tomorrow will be the heat. With winds out of the
southeast off of the Gulf of Mexico bringing in plenty of moisture
and an upper level ridge across Northern Mexico and the Texas Big
Bend Region highs will soar to some of the highest levels seen
this summer. Add onto that the humidity and the area will see heat
indices or "feels like" temperatures on the order of 107 to 113
degrees. Heat index values as of 2pm are already 108 from McAllen
to Harlingen, and up to 111 in Brownsville. Similar conditions are
expected for tomorrow. Based on this another Heat Advisory has
been issued for noon to 6pm on Saturday to match the one that was
issued for today.
The shear axis mentioned in this mornings forecast has shown up
as weaker and a bit delayed in the morning weather models. For
this reason have taken out PoPs other than low rain chances in the
off shore waters tomorrow morning to account for some isolated
convection similar to what was observed this morning.
.LONG TERM (Sunday through Friday):
There are two weather features that will possibly bring some
relief to the heat for late in the weekend into next week. The
first of these is the mid level shear axis that will move over the
Texas Coast and Deep South Texas on Sunday. This could possibly
spark off a shower or thunderstorm, but in general all of the
models have trended drier so confidence is low in seeing any heat
busting precipitation for the day on Sunday. If any showers/storms
do form they would likely be out over the off shore waters and
along the coast, with western areas remaining dry.
The next system that offers a glimmer of hope will be a strong
trough of low pressure that will dig across the Central Plains of
the US by the middle of the week. Indications are that it will
drag a boundary down into Texas, but most of the models agree in
keeping the bulk of moisture and most of the convection well to
the north of Deep South Texas, over Central and Northern parts of
the state. If the trough can drive any of the convection far
enough south, Wednesday through Friday could see some slight rain
chances enter the forecast, but for now high pressure looks to be
in control of the weather, which will only prolong the heat wave
across the area.
&&
.MARINE:
Seas this afternoon and tonight will remain around 4 feet in the
near shore waters, and 1 to 2 feet in the bays. With the stout
southeasterly wind seas will continue to be choppy which has also
contributed to the moderate risk of rip currents today. As
conditions calm behind the well inland and decaying Laura, seas
should lower to around 3 feet for tomorrow, before increasing
again on Sunday with the next week storm system approaching. The
heat will be on with near record temperatures, and heat indices as
high as 113. UV index values should continue to run in the extreme
category.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 80 95 80 95 / 0 10 10 10
BROWNSVILLE 82 97 82 96 / 0 10 10 10
HARLINGEN 80 99 79 98 / 0 10 10 10
MCALLEN 80 100 80 99 / 0 0 10 10
RIO GRANDE CITY 79 104 79 103 / 0 0 10 0
SOUTH PADRE ISLAND 84 89 84 89 / 0 10 10 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 6 PM CDT this evening for TXZ248>257-351-353.
Heat Advisory from noon to 6 PM CDT Saturday for TXZ248>257-351-
353.
GM...None.
&&
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
EWX 12Hazardous Weather Outlook National Weather Service Brownsville TX Issued by National Weather Service Austin/San Antonio TX 246 PM CDT Fri Aug 28 2020 TXZ248>257-351-353-292000- Zapata-Jim Hogg-Brooks-Inland Kenedy-Starr-Southern Hidalgo- Inland Willacy-Inland Cameron-Coastal Willacy-Coastal Cameron- Coastal Kenedy-Northern Hidalgo- 246 PM CDT Fri Aug 28 2020 This Hazardous Weather Outlook is for portions of Deep South Texas. .DAY ONE...This Afternoon and Tonight A heat advisory is in effect for all of Deep South Texas this afternoon as heat index values top out between 110-114 degrees. .DAYS TWO THROUGH SEVEN...Saturday through Thursday A heat advisory is all in effect for Saturday for heat index values forecast to range from 108 to 113 degrees. Additional heat headlines are possible for late in the weekend and into next week as the atmosphere remains hot. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. GMZ130-132-135-150-155-170-175-292000- Laguna Madre from the Port of Brownsville to the Arroyo Colorado- Laguna Madre from the Arroyo Colorado To 5 NM north of Port Mansfield TX- Laguna Madre from 5 nm north of Port Mansfield to Baffin Bay TX- Coastal waters from Port Mansfield to the Rio Grande out 20 nm- Coastal waters from Baffin Bay to Port Mansfield out 20 nm- Waters from Port Mansfield to the Rio Grande extending from 20 to 60 nm- Waters from Baffin Bay to Port Mansfield extending from 20 to 60 nm- 246 PM CDT Fri Aug 28 2020 This Hazardous Weather Outlook is for portions of The Gulf of Mexico and The Laguna Madre. .DAY ONE...This Afternoon and Tonight There is a moderate risk of rip currents today. Those out and about on the beaches and surfing today should be mindful of the moderate rip current risk. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Small craft advisories may be needed at times Sunday through Wednesday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
4 heat. Local standard time, as filed.
Heat indices around McAllen, TX exceeded 111 degrees for a couple of hours starting at 1:50 PM CDT and hovered around 112 degrees for a couple of hours during the afternoon of August 28th.
Heat indices around McAllen, TX exceeded 111 degrees for a couple of hours starting at 1:50 PM CDT and the MFE ASOS even exceeded 116 degrees for a period of time around 4 PM CDT.
Heat indices in Cameron County exceeded 111 degrees for a couple of hours starting at 1:50 PM CDT and the BRO ASOS even exceeded 114 degrees for a period of time around 3 PM CDT, and HRL topped at 112 degrees around 2 PM CDT.
Heat indices around Zapata, TX exceeded 111 degrees for a couple of hours starting around 4 PM CDT and the APY ASOS even exceeded 115 degrees for a period of time around 5 PM CDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2020Every state in 2020This day in weather historyWarnings in Texas, August 2020
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: 918536, 918529, 918532, 918534.