553  
FXUS64 KBRO 181140 AAA  
AFDBRO  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
540 AM CST WED DEC 18 2024  
   
..NEW AVIATION
 
 
   
SHORT TERM
 
 
(TODAY THROUGH THURSDAY)  
ISSUED AT 235 AM CST WED DEC 18 2024  
 
KEY MESSAGES:  
 
-FAVORABLE CONDITIONS FOR THE DEVELOPMENT OF EARLY MORNING FOG  
REMAIN LIKELY.  
 
-LOW RAIN CHANCES AROUND 30 PERCENT FOR TODAY.  
 
-LOW TEMPERATURES IN THE 50S FOR MOST OF THE REGION TONIGHT, WITH A  
FEW PLACES IN THE NORTHERN RANCHLANDS IN THE UPPER 40S.  
 
PLENTY OF LOW-LEVEL MOISTURE ALONG WITH CLEAR SKIES AND LIGHT WINDS,  
THE ENVIRONMENT IS PRIMED FOR THE DEVELOPMENT OF FOG FOR THIS  
MORNING. SOME OF THE CURRENT OBSERVATIONS DO SHOW THAT SOME FOG HAS  
STARTED TO DEVELOP IN THE REGION. AS OF THIS TIME, MOST OF  
OBSERVATIONS INDICATE THAT LIGHT FOG HAS STARTED TO APPEAR IN THE  
REGION. HOWEVER, THERE IS A LOW POSSIBILITY OF AROUND 30 PERCENT OF  
FOG LESS THAN HALF OF A MILE FOR MORNING. HOWEVER, THIS FOG IS  
EXPECTED TO LIFT SHORTLY AFTER SUNRISE.  
 
A COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION DURING THIS  
AFTERNOON AND INTO THIS EVENING. ISOLATED SHOWERS ARE POSSIBLE AS  
LOW-LEVEL MOISTURE POOLS AHEAD OF THE FRONT AND SOME OF THE  
INSTABILITY WITH THE FRONT CAN EVEN PRODUCE A THUNDERSTORM OR TWO.  
ONCE THE COLD FRONT MOVES THROUGH, THE DRY AIR BEHIND IT WILL PUT AN  
END TO THE POSSIBILITY OF RAIN FOR THE REST OF THE SHORT TERM  
FORECAST.  
 
AS FOR THE TEMPERATURES, THE HIGHS FOR TODAY ARE EXPECTED TO BE IN  
MOSTLY IN THE 80S TODAY. HOWEVER, THE LOW TEMPERATURES FOR TONIGHT  
WILL BE MUCH COLDER WITH LOWS EXPECTED TO BE IN THE 50S FOR MOST OF  
THE AREA, AND PARTS OF THE NORTHERN RANCHLANDS COULD EVEN GET INTO  
THE UPPER 40S. THE COOL AIR WILL PERSIST INTO THURSDAY AS WELL, AS  
THE HIGH TEMPERATURES ARE EXPECTED TO BE MOSTLY IN THE LOW 70S WITH  
A FEW PLACES IN THE UPPER 60S.  
 
FINALLY, A MODERATE RISK OF RIP CURRENTS IS EXPECTED TO CONTINUE  
THROUGH THE SHORT TERM FORECAST PERIOD.  
 

 
   
LONG TERM
 
 
(THURSDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 235 AM CST WED DEC 18 2024  
 
TRANQUIL WILL BE THE RULE FOR THIS PORTION OF THE TOTAL FORECAST.  
IN THE MIDDLE LAYERS OF THE ATMOSPHERE, THE BRO CWFA WILL INITIALLY  
BE ON THE NORTHWEST PERIPHERY OF 500 MB HIGH PRESSURE CENTERED  
EAST OF THE YUCATAN PENINSULA. GRADUALLY, AS THIS HIGH SHIFTS EAST,  
FRESH MID-LEVEL HIGH PRESSURE WILL DEVELOP AND BECOME CENTERED  
WEST OF THE BAJA PENINSULA, PLACING THE BRO CWFA IN A MORE  
NORTHWEST-TO-SOUTHEAST FLOW FOR THE REMAINDER OF THE LONG TERM  
FORECAST PERIOD. THE RESULT OF THIS VARIABLE SYNOPTIC PATTERN WILL  
BE DRY WEATHER ACROSS DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY.  
 
TEMPERATURE-WISE, GENERALLY INCREASING DAYTIME HIGHS AND  
OVERNIGHT LOWS ARE ANTICPATED AS AN ONSHORE FLOW SLOWLY DEVELOPS  
AND BECOMES MORE INTENSE. NEAR NORMAL VALUES AT THE START OF THE  
PERIOD WILL RISE TO WELL ABOVE NORMAL LEVELS AS WINDS BECOME  
BREEZY, MAINLY IN THE SUNDAY THROUGH TUESDAY TIME FRAME.  
 
FINALLY, AN ELEVATED RISK OF RIP CURRENTS, MODERATE TO HIGH, IS  
POSSIBLE AT THE LOCAL BEACHES MONDAY AND TUESDAY WITH INCREASING  
WINDS AND BUILDING SEAS FORECAST.  
 

 
   
AVIATION
 
 
(12Z TAFS)  
ISSUED AT 528 AM CST WED DEC 18 2024  
 
MOSTLY LIFR CONDITIONS ARE CURRENTLY PRESENT AND IS EXPECTED TO  
PERSIST THROUGH THE EARLY MORNING HOURS DUE TO THE PATCHY FOG.  
HOWEVER, AROUND 15Z THE FOG SHOULD LIFT. A COLD FRONT WILL MOVE  
THROUGH THE REGION. A ISOLATED SHOWERS AND A FEW THUNDERSTORMS  
WITH THE COLD FRONT ARE POSSIBLE, BUT NOT LIKELY ENOUGH TO INCLUDE  
IN THE TAF PACKAGE. AFTER THE FRONT PASSES THROUGH THE REGION, THE  
WINDS ARE EXPECTED TO SHIFT TOWARDS THE NORTH WHILE REMAINING  
LIGHT THROUGH THE PERIOD.  
 

 
   
MARINE
 
 
(TODAY THROUGH THURSDAY)  
ISSUED AT 235 AM CST WED DEC 18 2024  
 
FAVORABLE CONDITIONS WITH LIGHT TO MODERATE WINDS AND LOW TO  
MODERATE SEAS ARE EXPECTED FOR THE DAYTIME HOURS TODAY. HOWEVER A  
COLD FRONT IS EXPECTED TO MOVE THROUGH THE LOWER TEXAS COAST THIS  
AFTERNOON AND THROUGH THIS EVENING. AFTERWARDS, THE WINDS AND SEAS  
ARE EXPECTED TO BECOME SLIGHTLY ELEVATED TO REQUIRE SMALL CRAFT  
EXERCISE CAUTION DURING THE OVERNIGHT HOURS. HOWEVER, BY LATE  
TOMORROW MORNING FAVORABLE CONDITIONS AS THE WINDS AND SEAS ARE  
EXPECTED TO DIMINISH.  
 
(THURSDAY NIGHT THROUGH TUESDAY)  
LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS WILL PREVAIL  
ALONG THE LOWER TEXAS COAST THROUGH A MAJORITY OF THE PERIOD WITH  
HIGH PRESSURE IN PLACE OVER THE WESTERN GULF OF MEXICO. HOWEVER,  
AS THE HIGH SHIFTS EAST, AND THE PRESSURE GRADIENT INTENSIFIES,  
INCREASING WINDS AND BUILDING SEAS WILL OCCUR ON MONDAY AND  
TUESDAY, RESULTING IN THE POSSIBLE NEED FOR SMALL CRAFT SHOULD  
EXERCISE CAUTION TO EVEN SMALL CRAFT ADVISORY ON THOSE DAYS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
BROWNSVILLE 81 57 71 57 / 20 20 0 0  
HARLINGEN 82 53 71 53 / 20 20 0 0  
MCALLEN 84 56 72 57 / 30 40 0 0  
RIO GRANDE CITY 82 53 71 53 / 30 40 0 0  
SOUTH PADRE ISLAND 76 62 68 63 / 10 10 0 0  
BAYVIEW/PORT ISABEL 79 56 69 57 / 20 10 0 0  
 

 
   
BRO WATCHES/WARNINGS/ADVISORIES
 
 
TX...NONE.  
GM...NONE.  

 
 

 
 
SHORT TERM...64-KATZ  
LONG TERM....66-TOMASELLI  
AVIATION...64-KATZ  
 
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