The summer of heat just wouldn't end as heat indices pushed over 111 degrees for a few hours in Cameron, Willacy, and Kenedy Counties the afternoon of September 15th.
Every event with a place to put it; 5 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.
The summer of heat just wouldn't end as heat indices pushed over 111 degrees for a few hours in Cameron, Willacy, and Kenedy Counties the afternoon of September 15th.
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 Sep 15, 10:30 AM CST, 23 minutes earlier.
Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 1130 AM CDT Fri Sep 15 2023 ...New AVIATION... .SHORT TERM... (Today through Saturday) Issued at 339 AM CDT Fri Sep 15 2023 The persistent mid-level ridge finally starts to weaken or break down a bit into the beginning of the weekend, with a shortwave disturbance working south into the brush country by early Saturday before working east through the day. This bumps up the chance of rain and brings a much needed break in the record breaking heat. PWAT values surge towards 2.0 and 2.1 inches today and nearly 2.2 to 2.3 tomorrow with the shortwave, which even for September is above normal, nearing the 90th percentile today and near record values on Saturday. This indicates a better chance of efficient to abundant rainfall, especially late Friday night into Saturday. The Weather Prediction Center has placed Zapata, Jim Hogg, and Starr counties into a Marginal Risk of excessive rainfall leading into Saturday morning with a Slight Risk through Laredo. This could be very beneficial to the Rio Grande reservoirs and potentially lead to flash flooding through normally dry arroyos and creeks across the brush country. As the system works through the Rio Grande Valley, the sea breeze may help initiate additional storms or boundaries for storms to develop across through the afternoon. Highs once again approach record values today for BRO, HRL and MFE. Heat indices nudge towards 110 with the increasing moisture this afternoon and briefly touch Heat Advisory levels across Cameron County. At this time, do not expect a Heat Advisory to be needed, but will continue to monitor. Have gone a little below guidance for highs on Saturday, topping off into the mid 90s. This may still be too warm, with some guidance beginning to top off the ranchlands in the 80s and RGV near 90. This will be highly dependent on the development and persistence of rain south into the CWA tonight into Saturday. && .LONG TERM... (Saturday night through Thursday) Issued at 339 AM CDT Fri Sep 15 2023 Rain chances will continue and peak through weekend as a weak cold front across South Texas Saturday evening drifts southward towards Deep South Texas late Saturday night into Sunday. There remains some uncertainty if this frontal boundary will move through or stall across the CWA this weekend. Numerous to widespread showers and isolated to scattered thunderstorms will be possible Saturday night and Sunday, with the greatest chances and highest amounts expected between Saturday evening and Sunday evening near and along the frontal boundary. Some pockets of moderate to heavy rainfall will be possible, especially along and near the coast. Rainfall amounts will vary, but generally up to an inch can be expected through the weekend. Temperatures are expected to cool down this weekend, but should still remain a few degrees above normal. Ridging will build in over the Rockies and eventually the Plains early next week, with more of a northwesterly flow developing aloft. A more subsidence and drier airmass should decrease rain chances over region. However, low rain chances will linger through rest of the period, especially near the coast. As 500mb ridging builds in from the west early to midweek, afternoon high temperatures will trend warmer and back up into the upper 90s by midweek. && .AVIATION... (18Z TAFS) Issued at 1040 AM CDT Fri Sep 15 2023 VFR conditions now at the TAF sites. We are in a general thunderstorm outlook today and tomorrow, with the expectation that well above normal moisture will fuel isolated to scattered showers and thunderstorms with and along the sea breeze. However, under rather similar conditions the last couple of days, the sea breeze has not resulted in a lot of rain. Again today some of the convection allowing models are remaining conservative and are showing limited precip, preferring to delay enhanced precip probabilities for Saturday or Saturday night. At the moment, a stationary frontal boundary has sagged south to just north of the CWA. There is now convective potential upstream over Central Texas. If storms get going there later today, some activity could move southeast toward deep South Texas and the RGV by Saturday, though there is uncertainty. For now, will monitor afternoon sea breeze activation for TAF threatening storms. Conditions should remain VFR, but with the threat of gusty winds and cloud to ground lightning if any storms get going. && .MARINE... Issued at 339 AM CDT Fri Sep 15 2023 Now through Saturday...Generally favorable marine conditions are expected across the coastal waters through Saturday. The chance of showers and thunderstorms increases, especially overnight and into each morning offshore into Saturday. Winds and seas will be higher near any convection. Afternoon winds across the bay may build a moderate chop or choppy conditions leading to brief Small Craft Caution into the early evening hours today. Saturday night through Wednesday...Generally favorable conditions will prevail through much of the period as surface high pressure remains anchored across the Gulf of Mexico. Winds are expected to weaken Saturday night and Sunday as a frontal boundary drifts southward over the waters. Scattered to numerous showers and isolated to scattered thunderstorms will continue Saturday night into Sunday as deep moisture arrives and lingers across the area along the stalled front. Isolated to scattered showers and thunderstorms will linger across the waters through midweek. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 100 81 96 78 / 40 20 50 60 HARLINGEN 101 76 95 74 / 40 20 50 60 MCALLEN 103 79 97 76 / 30 30 60 50 RIO GRANDE CITY 104 79 97 75 / 20 30 60 60 SOUTH PADRE ISLAND 91 82 88 80 / 30 20 50 60 BAYVIEW/PORT ISABEL 97 79 92 76 / 30 20 50 60 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && SHORT TERM...54-BHM LONG TERM....67-Mejia AVIATION...54-BHM
Hazardous Weather Outlook National Weather Service Brownsville TX 408 AM CDT Fri Sep 15 2023 TXZ248>255-351-353>355-451-454-455-160915- Zapata-Jim Hogg-Brooks-Inland Kenedy-Starr-Southern Hidalgo- Inland Willacy-Inland Cameron-Coastal Kenedy-Northern Hidalgo- Coastal Willacy-Coastal Cameron-Kenedy Island-Willacy Island- Cameron Island- 408 AM CDT Fri Sep 15 2023 This Hazardous Weather Outlook is for portions of Deep South Texas. .DAY ONE...Today and Tonight Heat Index values will range between 105 to 110 degrees this afternoon. .DAYS TWO THROUGH SEVEN...Saturday through Thursday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed. GMZ130-132-135-150-155-170-175-160915- 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- Gulf waters from Port Mansfield to the Rio Grande out 20 nm- Gulf waters from Baffin Bay to Port Mansfield out 20 nm- Gulf waters from Port Mansfield to the Rio Grande extending from 20 to 60 nm- Gulf waters from Baffin Bay to Port Mansfield extending from 20 to 60 nm- 408 AM CDT Fri Sep 15 2023 This Hazardous Weather Outlook is for portions of The Gulf of Mexico and The Laguna Madre. .DAY ONE...Today and Tonight Isolated to scattered thunderstorms are possible over the Gulf waters. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Isolated to scattered thunderstorms are possible over the Gulf waters Friday through Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
5 heat. Local standard time, as filed.
The Cameron County Airport ASOS station recorded heat indices at or above 111 degrees from 11:53AM CDT until 3:53PM CDT.
The Cameron County Airport ASOS station recorded heat indices at or above 111 degrees from 11:53AM CDT until 3:53PM CDT. By proxy, it can be inferred that Coastal Willacy County also reached or exceeded 111 degrees for several hours.
The Brownsville/South Padre International Airport ASOS station recorded heat indices at or above 111 degrees from 1:24PM CDT until 4:52PM CDT. The Valley International Airport in Harlingen ASOS station recorded heat indices at or above 111 degrees from 2:52PM CDT through 4:52PM CDT.
By proxy with nearby ASOS, AWOS, and Texas Water Development Board Mesonet sites, it is realistic to interpolate heat index values between 111 and 115 degrees across inland Willacy County during the afternoon of September 15th. Slightly lower values are common here compared with locations in Kenedy and Cameron, due to the populated areas being in a zone of slightly lower, but still dangerous, high temperatures.
The observing station at Kingsville NAS reported a peak heat index of just below 117 degrees at 3:56 PM, with observations on either side between 111 and 112. Though this location runs higher than nearby areas, proxy between Coastal Willacy and Kingsville supports a two-hour period of heat index around 111 between 220 and 420 PM on the 15th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2023Every state in 2023This day in weather historyWarnings in Texas, September 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: 1121223, 1142652, 1121222, 1121224, 1142653.