055  
FXUS64 KBRO 272353 AAA  
AFDBRO  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
653 PM CDT TUE JUN 27 2017  
   
DISCUSSION
 
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 

 
   
AVIATION
 
DAYTIME CONVECTION HAS WANED WITH VFR TO PREVAIL  
AT THE 3 AIR TERMINALS OVERNIGHT. LOW PRESSURE TROUGH REMAINS EAST  
OF THE PADRE ISLAND AND AN UPPER LEVEL TROUGH PERSIST OVER SOUTH  
TEXAS WITH ABUNDANT MOISTURE IN PLACE KEEPING THE CHANCE OF  
ADDITIONAL SHOWERS AND THUNDERSTORMS IN THE FORECAST. EXPECTED  
ACTIVITY TO REFIRE OVER THE GULF WATERS OVERNIGHT AND DRIFT  
TOWARDS THE COAST AND THE EASTERN COUNTIES AROUND SUNRISE  
WEDNESDAY INCREASIKNG IN COVERAGE EAST TO WEST DURING THE LATE  
MORNING AND AFTERNOON HOURS. MOSTLY VFR WITH SOME BRIEF MVFR CIGS  
CAN BE EXPECTED WITH THE SCATTERED CONVECTION. WINDS WILL BE LIGHT  
AND VARIABLE TONIGHT WITH LIGHT EAST TO SOUTHEAST.  
 

 
   
PREV DISCUSSION
 
/ISSUED 320 PM CDT TUE JUN 27 2017/  
 
SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT): A WEAK MID-LEVEL  
TROUGH IN THE 500MB FLOW IS LOCATED OVER SOUTH TEXAS ALONG WITH  
SURFACE TROUGHING ALONG THE LOWER TEXAS COAST. WITH ABUNDANT  
MOISTURE FROM THE SURFACE UP TO 500MB, SHOWER AND THUNDERSTORM  
CHANCES WILL CONTINUE THROUGH THIS EVENING. LOCALLY HEAVY RAINFALL  
WILL BE POSSIBLE WITH PRECIPITABLE WATER VALUES AT 2.25",  
MEASURED FROM THE 12Z BRO SOUNDING. TONIGHT, A FAIRLY WEAK  
VORTICITY MAXIMUM IS BEING NOTED IN THE 12Z MODEL GUIDANCE, SO  
ANOTHER ROUND OF SHOWERS OR STORMS IS POSSIBLE LATE TONIGHT ACROSS  
DEEP SOUTH TEXAS. THE HRRR HAS CONSISTENTLY BEEN PICKING UP ON  
ISOLATED CONVECTION AS WELL, SO HAVE LEFT SLIGHT CHANCE POPS IN  
FOR 00-06Z TONIGHT.  
 
WEDNESDAY, MID-LEVEL TROUGH AXIS WILL LIKELY BE ORIENTED ALONG THE  
COASTAL AREAS, SO THE MAIN RAIN CHANCES WILL BE OVER THE EASTERN  
HALF OF DEEP SOUTH TEXAS AND OVER THE MARINE AREAS. TEMPERATURES  
SHOULD BE ABLE TO WARM UP A FEW MORE DEGREES THAN TODAY DUE TO  
SLIGHTLY LOWER RAIN CHANCES AND CLOUDS EXPECTED. SURFACE HIGH  
PRESSURE WILL BUILD OVER THE SOUTHEAST US, SO WINDS WILL RETURN TO  
THE SOUTHEAST GOING INTO THURSDAY AFTERNOON.  
 
LONG TERM (THURSDAY THROUGH TUESDAY): WEAK H5 TROUGH BETWEEN  
RIDGES TO THE EAST AND WEST WILL BEGIN TO BREAK DOWN THURSDAY INTO  
FRIDAY, ALLOWING THE EASTERN RIDGE TO BUILD BACK INTO SOUTH TEXAS.  
THERE WILL STILL BE ENOUGH INSTABILITY AND MOISTURE IN THE REGION  
THURSDAY TO PROVIDE A SLIGHT CHANCE FOR SHOWERS ON THURSDAY, BUT  
LOW LEVEL JET WILL INCREASE SHEAR ON ANY OF THESE SHOWERS. DRIER  
AIR MOVES IN ALOFT BY FRIDAY MORNING, BRINGING NEARLY ALL SHOWER  
ACTIVITY TO AN END AT LEAST THROUGH THE WEEKEND, AND LIKELY INTO  
EARLY NEXT WEEK. THIS WILL ALLOW TEMPERATURES TO SLOWLY INCREASE  
EACH AFTERNOON THROUGH THE 90S AND ABOVE THE 100 DEGREE MARK OUT  
WEST.  
 
MARINE: NOW THROUGH WEDNESDAY NIGHT: WEAK SURFACE TROUGHING  
ALONG THE COAST WILL MAINTAIN LIGHT AND MAINLY VARIABLE WINDS OVER  
THE LOWER TEXAS COASTAL WATERS TONIGHT INTO WEDNESDAY, WITH  
EXCEPTION TO NEAR ANY THUNDERSTORMS THAT DEVELOP. SURFACE HIGH  
PRESSURE WILL BUILD AND SHIFT TO THE SOUTHEAST US AND RETURN  
SOUTHEAST FLOW LATE IN THE PERIOD ON THURSDAY. AS LOW PRESSURE  
DEEPENS IN THE CENTRAL PLAINS, WINDS WILL INCREASE AND SEAS WILL  
EVENTUALLY BUILD TO 3 TO 4 FEET.  
 
THURSDAY THROUGH SUNDAY: INCREASING GRADIENT THROUGH THE WEEKEND  
WILL CAUSE GUSTY SOUTHEAST WINDS FOR THE MARINE AREAS. SOUTHEAST  
WINDS WILL REACH NEAR 20 KNOTS EACH DAY, APPROACHING ADVISORY  
CRITERIA. THIS WILL ALSO KICK SEAS UP TO 5 TO 6 FEET OFFSHORE AND  
CAUSE CHOPPY LAGUNA WATERS. SOME IMPROVEMENT IS NOTED FOR SUNDAY,  
WITH WINDS WEAKENING TO 10 TO 15 KNOTS. SEAS MAY TAKE A WHILE TO  
DECREASE SUNDAY MORNING ONCE THE WINDS DECREASE.
 
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
BAYVIEW/PORT ISABEL 76 91 78 93 / 20 40 30 30  
BROWNSVILLE 75 93 78 94 / 20 30 20 30  
HARLINGEN 74 94 76 96 / 20 30 20 30  
MCALLEN 76 97 78 99 / 20 20 20 20  
RIO GRANDE CITY 75 98 77 101 / 20 10 10 10  
SOUTH PADRE ISLAND 80 88 81 88 / 20 40 30 30  
 

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

 
 

 
 
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:  
HTTP://WEATHER.GOV/RGV  
 
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