280
FXUS64 KBRO 201800
AFDBRO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
100 PM CDT WED MAY 20 2026
..NEW DISCUSSION, AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1246 PM CDT WED MAY 20 2026
KEY MESSAGES:
* DAY-TO-DAY OR NEAR DAY-TO-DAY CHANCES FOR SHOWERS AND
THUNDERSTORMS IS EXPECTED THROUGH NEXT WEEKEND AND POSSIBLY BEYOND
AMID A MAJOR SHIFT IN THE WEATHER PATTERN.
* STRONG TO SEVERE THUNDERSTORMS ALONG WITH HEAVY RAINFALL AND
LOCALIZED FLOODING IS POSSIBLE THROUGH NEXT WEEKEND.
* STORM PREDICTION CENTER HAS A MARGINAL RISK (LEVEL 1 OF 5) FOR
ZAPATA AND THE WESTERN PORTIONS OF STARR AND JIM HOGG. THE REST
OF THE REGION IS IN A GENERAL THUNDERSTORM OUTLOOK.
* WEATHER PREDICTION CENTER HAS A MARGINAL RISK (LEVEL 1 OF 4) FOR
ZAPATA, MOST OF JIM HOGG, NORTHWESTERN STARR, AND NORTHWESTERN
BROOK COUNTIES FOR EXCESSIVE RAINFALL.
DISCUSSION
ISSUED AT 1246 PM CDT WED MAY 20 2026
EVEN THOUGH AN ACTIVE LINE OF SHOWERS AND THUNDERSTORMS MOVED
THROUGH THE REGION THIS MORNING, THERE IS A POSSIBILITY THAT ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS COULD MOVE THROUGH THE REGION
TONIGHT OFF OF THE SIERRA MADRE. SEVERAL CAMS SHOWS THAT THERE IS
ANOTHER SYSTEM THAT COULD DEVELOP DURING THE OVERNIGHT HOURS. THIS
COULD BE ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS FOR DEEP
SOUTH TEXAS AND THE RIO GRANDE VALLEY. IT SHOULD BE NOTED AS OF THE
TIME OF WRITING, THAT SPC DOES HAVE ZAPATA AND THE WESTERN
PORTIONS OF STARR AND JIM HOGG IN A MARGINAL RISK (LEVEL 1 OF 5)
FOR SEVERE WEATHER TONIGHT, WHILE THE REST OF THE AREA IS IN A
GENERAL THUNDERSTORM OUTLOOK. THIS IS JUST TO HIGHLIGHT WERE THE
MORE LIKELY AREA TO BE IMPACTED BY SEVERE WEATHER IS, BUT DOES NOT
LIMIT IT TO THAT REGION. ON TOP OF THIS, WPC DOES HAVE ZAPATA,
MOST OF JIM HOGG, NORTHWESTERN STARR, AND NORTHWESTERN BROOKS IN
A MARGINAL RISK (LEVEL 1 OF 4) FOR EXCESSIVE RAINFALL TONIGHT.
THE REST OF THE PERIOD CAN GENERALLY BE SUMMARIZED AS ON AND OFF
PERIODS OF RAIN. WHILE SOME OF THESE SHOWERS AND THUNDERSTORMS COULD
PRODUCE HEAVY RAINFALL AND SOME LOCALIZED FLOODING BASED ON THE
ENVIRONMENTAL SET UP. SOUTHWESTERLY FLOW ALOFT ALONG WITH SOME
SHORTWAVES MOVING OVER THE SIERRA MADRE, SOUTHEASTERLY FLOW AT THE
SURFACE TO BRING IN MOISTURE FROM THE GULF, AND A FRONTAL BOUNDARY
STALLED TO THE NORTH. WPC DOES HAVE DEEP SOUTH TEXAS AND THE RIO
GRANDE VALLEY IN A MARGINAL RISK OF EXCESSIVE RAINFALL FOR DAYS 2,
4, AND 5 WITH DAYS 2 AND 4 HAVING A SLIM PART OF NORTHERN KENEDY IN
A SLIGHT (LEVEL 2 OF 4). MOST LIKELY RAINFALL AMOUNTS COULD BE IN
THE RANGE OF 2 TO 2.5 INCHES FOR THE NORTHERN RANCHLANDS WHILE AREAS
IN THE LOWER VALLEY COULD SEE 1 TO 2 INCHES. HOWEVER, THERE IS A LOW
CHANCE (10%) THAT WE COULD SEE RAINFALL TOTALS NEAR 3 TO 4 INCHES
FOR THE NORTHERN RANCHLANDS WITH 2 TO 3 INCHES POSSIBLE IN THE LOWER
VALLEY.
AS FOR THE TEMPERATURES, THE HIGH TEMPERATURES SHOULD GENERALLY BE
IN THE RANGE OF THE UPPER 80S TO LOWER 90S FOR THE MAJORITY OF THE
FORECAST PERIOD. WHILE THE LOWS ARE IN THE 70S.
AVIATION
(18Z TAFS)
ISSUED AT 1246 PM CDT WED MAY 20 2026
VFR CEILINGS ARE EXPECTED FOR THE MAJORITY OF THE AFTERNOON AND
EARLY EVENING HOURS, EVEN THOUGH THERE WILL BE SOME LINGERING
CLOUDS OVER THE AREA. MVFR CEILINGS DO RETURN TONIGHT AS A LOW-
LEVEL CLOUD DECK MOVES OVER THE AREA. PROB30 GROUPS HAVE BEEN USED
TO TRY TO TIME POSSIBLE SHOWERS AND THUNDERSTORMS MOVING OVER THE
AREA AS THEY COULD MOVE WEST TO EAST DURING THE OVERNIGHT HOURS.
MFE IS LIKELY TO SEE IMPACTS SHORTLY AFTER MIDNIGHT AND IT WILL
TAKE A FEW HOURS FOR HRL AND THEN BRO TO SEE THOSE IMPACTS AS
WELL. IT IS POSSIBLE THAT HEAVY DOWNPOURS FROM THESE STORMS REDUCE
VISIBILITIES TO LIFR AT TIMES. LIGHT EASTERLY WIND ARE EXPECTED
FOR THE LARGE PORTION OF THE TAF CYCLE AT ALL TAF SITES, ALTHOUGH
A FEW GUSTS UP TO 20 KNOTS ARE POSSIBLE AT HRL.
MARINE
ISSUED AT 1246 PM CDT WED MAY 20 2026
SHOWERS AND THUNDERSTORMS OVER THE LOWER TEXAS COAST ARE
EXPECTED TO BE THE BIGGEST HAZARD FOR FORECAST PERIOD. RAIN CHANCES
REMAIN NEAR MEDIUM (50%) EACH DAY. SHOWERS AND THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING HEAVY DOWNPOURS THAT WILL REDUCE VISIBILITIES
AND LOCALLY ELEVATED WINDS AND SEAS.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 78 89 78 92 / 40 50 30 10
HARLINGEN 75 88 75 92 / 40 50 20 20
MCALLEN 76 89 76 94 / 40 50 30 20
RIO GRANDE CITY 73 89 74 94 / 60 50 40 10
SOUTH PADRE ISLAND 79 84 80 86 / 30 50 30 10
BAYVIEW/PORT ISABEL 77 88 78 91 / 30 50 30 20
BRO WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
SHORT TERM...64-KATZ
LONG TERM....64-KATZ
AVIATION...64-KATZ
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