517
FXUS64 KBRO 180552 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1252 AM CDT THU JUN 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1244 AM CDT THU JUN 18 2026
* EXCESSIVE HEAT WARNING IS IN EFFECT FOR ALL OF DEEP SOUTH
TEXAS, EXCLUDING THE ISLAND FROM 11 AM TO 8 PM CDT THURSDAY.
* PEAK HEAT INDICES (FEEL-LIKE) TEMPERATURES BETWEEN 116-125F
DEGREES WILL RESULT IN WIDESPREAD MAJOR (LEVEL 3 OF 4) HEAT RISK
ON THURSDAY.
* ANOTHER HOT DAY IS EXPECTED ON FRIDAY WITH PEAK HEAT INDICES
RANGING BETWEEN 100-120F DEGREES.
* SLIGHT (LOW-MEDIUM) RAIN CHANCES FRIDAY NIGHT THROUGH SATURDAY
NIGHT; BEST CHANCES BRUSH COUNTRY.
* VERY WARM TO HOT AND HUMID CONDITIONS WILL CONTINUE THROUGH THE
MIDDLE PARTS OF NEXT WEEK.
DISCUSSION
ISSUED AT 1044 PM CDT WED JUN 17 2026
VERY WARM TO HOT AND HUMID CONDITIONS WILL BE THE MAIN WEATHER
STORYLINE THROUGH THE FORECAST PERIOD OR THROUGH THE MIDDLE PARTS OF
NEXT WEEK. THE INITIAL SURGE IN THE HEAT AND HUMIDITY THROUGH FRIDAY
IS STEMMING FROM THE DEPARTURE OF TROPICAL STORM ARTHUR. THE SECOND
SURGE IN THE HEAT NEXT WEEK WILL STEM FROM A BROAD AND ANOMALOUSLY
STRONG 591-594 DAM HEAT RIDGE. THROUGH NEXT WEEK, MOSTLY RAIN-FREE
WEATHER CONDITIONS CAN BE EXPECTED AS HIGH PRESSURE NEAR THE SFC AND
ALOFT WILL PROVIDE PLENTY OF SUBSIDENCE TO STIFLE ANY RAIN CHANCES
(FOR THE MOST PART). FRIDAY NIGHT THROUGH SATURDAY NIGHT WILL BE OUR
NEXT BEST CHANCES FOR ANY RAIN (LOWEST OVER THE LOWER VALLEY;
HIGHEST OVER THE NORTHERN RANCHLANDS AND WEST OF IH-69C/US-281).
TONIGHT THROUGH FRIDAY: IN THE WAKE OF TROPICAL STORM ARTHUR,
HEAT AND HUMIDITY LEVELS HAVE AND WILL CONTINUE TO SURGE. THURSDAY
WILL BE THE EPICENTER OF THIS HEAT EVENT. THAT'S WHEN DAYTIME
HIGH TEMPERATURES ARE PROGGED TO CLIMB INTO THE UPPER 90S TO MID
100S UNDER SUNNY TO MOSTLY SUNNY SKIES. WHEN YOU FACTOR IN THE
HUMIDITY LEVELS WITH DEWPOINTS IN THE UPPER 70S TO LOWER 80S, PEAK
HEAT INDICES OR "FEEL-LIKE" TEMPERATURES WILL CLIMB INTO
DANGEROUS LEVELS WITH VALUES RANGING BETWEEN 116-125F DEGREES.
THIS IS SOME OF THE HOTTEST TEMPERATURES IN 2-3 YEARS, SINCE
SUMMER OF 2024 AND MAYBE EVEN GOING BACK TO THE SUMMER OF 2023.
THESE ANOMALOUSLY HIGH TEMPERATURES WILL YIELD WIDESPREAD MAJOR
(LEVEL 3 OF 4) HEAT RISK ON THURSDAY. FRIDAY WILL BE A RINSE AND
REPEAT EFFORT, THOUGH THE HEAT WILL BE SLIGHTLY WEAKER COMPARED TO
THURSDAY. HIGH TEMPERATURES ON FRIDAY ARE EXPECTED TO RANGE
BETWEEN THE MID 90S TO NEAR 100F DEGREES. THIS WILL RESULT IN PEAK
HEAT INDICES RANGING BETWEEN 110- 120F DEGREES, WHICH WILL RESULT
IN MODERATE (LEVEL 2 OF 4) TO MAJOR (LEVEL 3 OF 4) HEAT RISK.
ANOTHER HEAT WARNING OR ADVISORY MAY BE NEEDED. TEMPERATURES
TONIGHT THROUGH FRIDAY NIGHT WILL PROVIDE LITTLE TO NO RELIEF IN
THE HEAT WITH OVERNIGHT LOWS HOLDING MAINLY IN THE LOWER 80S.
SATURDAY: THERE WILL BE A SLIGHT REPRIEVE IN THE HOT TEMPERATURES ON
SATURDAY (STILL VERY WARM HOWEVER) AS THE HEAT RIDGE WEAKENS
(SLIGHTLY). THE SLIGHT WEAKENING OF THE RIDGE COULD OPEN UP THE DOOR
FOR SHOWER AND THUNDERSTORM CHANCES FRIDAY NIGHT THROUGH SATURDAY
NIGHT. CURRENTLY, WE HAVE LOW-MEDIUM (20-40%) RAIN CHANCES FRIDAY
NIGHT OVER JIM HOGG, STARR, AND ZAPATA COUNTIES. ON SATURDAY, WE
HAVE LOW-MEDIUM (20-40%) CHANCES FOR DIURNAL SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF DEEP SOUTH TEXAS (LOWEST LOWER VALLEY
AND HIGHEST ACROSS BRUSH COUNTRY). FINALLY, SATURDAY NIGHT, WE HAVE
LOW-MEDIUM (20-40%) CHANCES FOR SHOWERS AND THUNDERSTORMS OVER JIM
HOGG, STARR, AND ZAPATA COUNTIES. GIVEN THE POTENTIAL FOR ADDITIONAL
CLOUD COVERAGE AND SHOWERS/STORM PROSPECTS AMID THE BRIEF 500 MB
RIDGE WEAKNESS, HIGH TEMPERATURES WILL BE SLIGHTLY LOWER THAN
PRIOR DAYS (POSSIBLY THE COOLEST OF THE FORECAST PERIOD) WITH
VALUES IN THE LOW TO MID 90S. PEAK HEAT INDICES WILL RANGE BETWEEN
100-112F DEGREES. STILL, A SPECIAL WEATHER STATEMENT (SPS) MAY BE
NEEDED ON SUNDAY. LITTLE TO NO RELIEF FROM THE HEAT IS EXPECTED
WITH OVERNIGHT LOWS SATURDAY MAINLY IN THE LOWER 80S.
SUNDAY THROUGH THURSDAY OF NEXT WEEK: FORECAST MODELS AND ENSEMBLES
ARE DEPICTING THE HEAT RIDGE EXPANDING OVER THE SOUTHERN U.S. AND
STRENGTHENING SUNDAY INTO NEXT WEEK. WITH A STRONG 591-594 DAM
HEAT RIDGE EMERGING OVER THE REGION, VERY WARM TO HOT TEMPERATURES
WILL CONTINUE. WE'LL CONTINUE TO KEEP AN EYE ON THE HEAT TRENDS,
BUT SO FAR DAYTIME HIGHS ARE EXPECTED TO RE-EMERGE INTO THE MID TO
NEAR 100F DEGREES SUNDAY THROUGH THURSDAY OF NEXT WEEK. DURING
THIS TIME, THE COMBINATION OF THE HEAT AND HUMIDITY WILL RESULT
IN PEAK INDICES RANGING BETWEEN 100-115F DEGREES EACH DAY.
ADDITIONAL HEAT ADVISORIES MAY BE NEEDED. LITTLE TO NO RELIEF FROM
THE HEAT IS EXPECTED WITH OVERNIGHT LOWS SATURDAY MAINLY IN THE
LOWER 80S.
AVIATION
(06Z TAFS)
ISSUED AT 1244 AM CDT THU JUN 18 2026
LIGHT TO MODERATE SOUTHEAST WINDS WITH SOME LOW STRATUS AND PATCHY
FOG ACROSS PORTIONS OF DEEP SOUTH TEXAS EARLY THIS MORNING. LATEST
SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE SOME REDUCED
VISIBILITIES AND LOW CEILINGS LEADING TO MVFR CONDITIONS AT LOCAL
AERODROMES. A MIX OF VFR/MVFR CONDITIONS WILL LIKELY CONTINUE
OVERNIGHT WITH FULL VFR CONDITIONS EXPECTED TO RETURN MID TO LATE
MORNING. SOUTHEAST WINDS BETWEEN 6 TO 12 KTS OVERNIGHT WILL
INCREASE AND BECOME BREEZY LATER THIS MORNING WITH SOME GUSTS
AROUND 25 KTS IN THE AFTERNOON. MVFR CONDITIONS MAY RETURN LATE
IN THE PERIOD.
MARINE
ISSUED AT 1044 PM CDT WED JUN 17 2026
ADVERSE TO HAZARDOUS MARINE CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD OR THROUGH NEXT WEEK. MAINLY SMALL CRAFT EXERCISE
CAUTION (SCEC) CONDITIONS CAN BE EXPECTED, BUT THERE COULD BE
PERIODS OF HIGH END SCEC TO LOW END SMALL CRAFT ADVISORY
CONDITIONS, PARTICULARLY THURSDAY EVENING INTO FRIDAY AND AGAIN
LATE SATURDAY INTO MONDAY MORNING.
CLIMATE
ISSUED AT 1044 PM CDT WED JUN 17 2026
FOLLOWING THE PASSAGE OF NOW TROPICAL STORM ARTHUR, HOT AND HUMID
CONDITIONS HAVE EMERGE OVER DEEP SOUTH TEXAS AND THE RIO GRANDE
VALLEY. A RECORD HIGH OF 98F DEGREES WAS TIED AT KBRO ON WEDNESDAY.
THIS TIED WITH THE YEARS 1900, 2011, AND 1989. ADDITIONAL HEAT
RECORDS ARE POSSIBLE ON THURSDAY, SPECIFICALLY OVER KBRO AND
KHRL. BELOW IS A LIST OF THE RECORD HIGHS FOR THURSDAY JUNE 18.
RECORD HIGHS FOR JUNE 18:
BROWNSVILLE: 98F DEGREES (2012, 1934, AND 1896)
HARLINGEN: 102F DEGREES IN 1934
MCALLEN: 105F DEGREES IN 2023
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 97 84 96 84 / 0 0 0 0
HARLINGEN 99 81 96 81 / 0 0 0 0
MCALLEN 102 83 98 83 / 0 0 0 0
RIO GRANDE CITY 104 81 99 80 / 0 0 10 20
SOUTH PADRE ISLAND 91 85 90 85 / 0 0 0 0
BAYVIEW/PORT ISABEL 97 83 94 83 / 0 0 0 0
BRO WATCHES/WARNINGS/ADVISORIES
TX...EXTREME HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM CDT THIS
EVENING FOR TXZ248>255-351-353>355.
GM...NONE.
SHORT TERM...23-EVBUOMA
LONG TERM....23-EVBUOMA
AVIATION...63-KC
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