246  
FXUS64 KBRO 212042  
AFDBRO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
242 PM CST SAT DEC 21 2024  
   
..NEW SHORT TERM, LONG TERM, MARINE
 
 
   
SHORT TERM
 
 
(TONIGHT THROUGH SUNDAY NIGHT)  
ISSUED AT 1259 PM CST SAT DEC 21 2024  
 
A WEAK MID-LEVEL PERTURBATION SWINGS ACROSS TEXAS TONIGHT THROUGH  
SUNDAY NIGHT, WITH THE SURFACE RIDGE OF HIGH PRESSURE EDGING  
FURTHER OFFSHORE. THIS WILL TURN LIGHT NORTHEASTERLY WINDS  
SOUTHEASTERLY INTO SUNDAY, INCREASING MOISTURE, AND COMBINING  
WITH THE EXTRA LIFT TO BUILD CLOUD COVER ACROSS DEEP SOUTH TEXAS  
INTO SUNDAY NIGHT. HAVE KEPT POPS LOW, BELOW 15 PERCENT, BUT  
HIGHER THAN NBM ACROSS THE CWA, ESPECIALLY THE MID TO LOWER  
VALLEY, FOR A FEW SPRINKLES OR PASSING BOUTS OF LIGHT RAIN SUNDAY  
THROUGH SUNDAY NIGHT. OVERALL, MOST LOCATIONS WILL REMAIN DRY AND  
CLOUD COVER WILL HELP KEEP LOWS TONIGHT AND SUNDAY NIGHT WARMER,  
WITH HIGHS TOMORROW SIMILAR TO TODAY, NEAR NORMAL FOR LATE  
DECEMBER. WITH THE INCREASE IN MOISTURE AND LIGHT WINDS, SOME  
PATCHY FOG MAY DEVELOP TONIGHT, MAINLY ACROSS THE RANCHLANDS.  
 

 
   
LONG TERM
 
 
(MONDAY THROUGH NEXT SATURDAY)  
ISSUED AT 1259 PM CST SAT DEC 21 2024  
 
* UNSEASONABLY WARM WEATHER WILL LIKELY PERSIST MOST OF THE WEEK.  
CHRISTMAS DAY SHOULD BE QUIET WITH WELL ABOVE NORMAL TEMPS  
RANGING FROM THE UPPER 70S TO THE MID 80S.  
 
INHERITED A SOLID FORECAST FROM THE PREVIOUS SHIFT. CONTINUED BY  
LOADING THE LATEST NBM WITH FEW CHANGES. THE ABOVE AVERAGE TEMP  
TREND REMAINS INTEGRAL TO THE MODEL OUTPUT. LOOKING BACK OVER THE  
LAST FEW DAYS OF THE GFS OUTPUT, DESPITE SOME SMALL ELEMENT OF  
VARIABILITY, MODEL CONTINUITY HAS BEEN QUITE CONSISTENT, PROVIDING  
ABOVE AVERAGE CONFIDENCE IN THE TEMPERATURE FORECAST. AN NBM  
REASONABLE WORST CASE SCENARIO FOR BROWNSVILLE IS NOT LARGE, 81  
DEGREES + OR - 4 TO 5 DEGREES. THIS (2024) WILL CERTAINLY NOT BE A  
"WHITE/COLD" CHRISTMAS.  
 
CPC'S (CLIMATE PREDICTION CENTER) 6-10 DAY TEMPERATURE OUTLOOK  
NOW CALLS FOR A 70 TO 90 PERCENT PROBABILITY OF ABOVE NORMAL  
TEMPERATURES FOR DEEP SOUTH TEXAS. THUS, EVEN THOUGH A COLD FRONT  
WILL APPROACH US ON CHRISTMAS EVE, SETTING UP LIGHT WINDS AND A  
NIGHT OF FOG (SANTA MAY NEED THE HELP OF RUDOLPH'S RED NOSE), THE  
FRONT ITSELF APPEARS TO ONLY PROVIDE A GLANCING BLOW. HENCE, THE  
CHRISTMAS DAY FORECAST WILL FEATURE UNSEASONABLY WARM HIGH TEMPS  
IN THE UPPER 70S TO MID 80S. FOR REFERENCE, RGV HIGH TEMPS IN  
LATE DECEMBER ARE TYPICALLY IN THE LOWER 70S. NOT ONLY IS IT  
NEARLY CERTAIN (90 TO 100 PERCENT) THAT WE WILL SEE SOME HIGH  
TEMPS 10 DEGREES ABOVE NORMAL, THERE IS A SMALL CHANCE (5 TO 10  
PERCENT) THAT THOSE HIGH TEMPS COULD REACH 86 TO 88 DEGREES, WHICH  
WILL BE DAILY RECORD TERRITORY FOR KBRO AND KHRL. FORECAST  
SOUNDINGS SUGGEST THAT 925 MB TEMPERATURES WILL BE 20 TO 23C, NEAR  
MAXIMUM SPC SOUNDING CLIMATOLOGY FOR THE BROWNSVILLE, TX UPPER  
AIR SITE. WITH AT LEAST PARTLY SUNNY SKIES EXPECTED, IT MIGHT FEEL  
MORE LIKE EARLY OCTOBER THAN LATE DECEMBER.  
 
BOXING DAY (DECEMBER 26) MIGHT EVEN GET A SKOSH WARMER THAN  
CHRISTMAS DAY ITSELF, WITH HIGH TEMPS IN THE LOWER TO MID 80S, BUT  
FOR LOCATIONS ALONG AND WEST OF THE I-69C/US-281 CORRIDOR  
POTENTIALLY PUSHING UPPER 80S TO NEAR 90 AS A RESULT OF POTENTIAL  
DOWNSLOPING, WHICH WOULD ONCE AGAIN THREATEN RECORD BREAKING HIGH  
TEMPS. CLOSER TO THE COAST AND LOWER RGV, A WEAK DISTURBANCE THAT  
IS PROGGED TO LIFT NORTHWARD FROM VERACRUZ INTO THE GULF OF MEXICO  
COULD LEAD TO ISOLATED TO SCATTERED SHOWERS, MAINLY OVER THE GULF  
BUT MAY ALSO PROVIDE MORE CLOUD COVER ACROSS OUR COASTAL ZONES.  
EVEN WITHOUT A TRIGGER (WEAK DISTURBANCE), ISOLATED GULF SHOWERS  
WILL BE POSSIBLE FROM TIME TO TIME ON ESTABLISHED RETURN FLOW.  
 
A HIGHLY PROGRESSIVE UPPER LEVEL FLOW PATTERN CONSISTENT WITH A  
POSITIVE NAO OR LACK OF BLOCKING OVER GREENLAND MEANS THAT THE  
NORTHERN AND SOUTHERN STREAM REMAIN SEPARATE. IN OTHER WORDS, THE  
REPEATED SHOTS OF COLD AIR INFILTRATING THE PLAINS AND MIDWEST  
WILL BE SHUT OUT OF DEEP SOUTH TEXAS. NOT SURPRISINGLY, THE NAEFS  
ENSEMBLE SITUATIONAL AWARENESS TABLE SHOWS 1000-850MB TEMPS 1 TO  
2 STANDARD DEVIATIONS ABOVE NORMAL FOR THE ENTIRE LONG TERM  
FORECAST. ANOTHER COLD FRONT WILL APPROACH ON FRIDAY, BUT THE  
TIMING DETAILS OF THE FRONTAL PASSAGE AND HOW COOL IT GETS REMAIN  
UNCERTAIN.  
 

 
   
AVIATION
 
 
(18Z TAFS)  
ISSUED AT 1126 AM CST SAT DEC 21 2024  
 
VFR CONDITIONS ARE EXPECTED TO GENERALLY PREVAIL THROUGH THE TAF  
PERIOD, WITH INCREASING MID TO HIGH CLOUDS FROM SOUTH TO NORTH  
INTO SUNDAY AFTERNOON. BRIEF MVFR CEILINGS MAY ROAM NORTH OF THE  
BORDER OCCASIONALLY TONIGHT AND SUNDAY MORNING. OTHERWISE, EXPECT  
LIGHT NORTHEASTERLY WINDS TO TURN SOUTHEASTERLY INTO SUNDAY.  
 

 
   
MARINE
 
 
ISSUED AT 1259 PM CST SAT DEC 21 2024  
 
NOW THROUGH SUNDAY NIGHT...HIGH PRESSURE WORKS FURTHER EAST,  
TURNING LIGHT NORTHEASTERLY WINDS SOUTHEASTERLY THROUGH THE  
REMAINDER OF THE WEEKEND. GENERALLY FAVORABLE MARINE CONDITIONS  
ARE EXPECTED TO CONTINUE. A FEW SPRINKLES OR PASSING LIGHT  
SHOWERS ARE POSSIBLE SUNDAY THROUGH SUNDAY NIGHT.  
 
MONDAY THROUGH THURSDAY NIGHT...LOOK FOR MOSTLY LIGHT TO MODERATE  
SOUTHEAST TO SOUTH WINDS AND A LIGHT TO MODERATE CHOP ON THE  
LAGUNA MADRE WITH MODERATE GULF WAVE HEIGHTS. THE LOW KEY MARINE  
WEATHER FORECAST IS PREDICATED ON THE PAUCITY OF SIGNIFICANT  
WEATHER SYSTEMS MOVING INTO THE AREA. PATCHY FOG MAY DEVELOP  
PURSUANT TO VERY LIGHT WINDS EARLY WEDNESDAY MORNING AS AN  
EXTENSION OF FOG EXPECTED OVER LAND AREAS. A FEW SHOWERS MAY  
DEVELOP FROM TIME TO TIME IN RETURN FLOW ALONG THE COAST.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
BROWNSVILLE 62 74 65 79 / 0 10 10 0  
HARLINGEN 56 74 60 81 / 0 10 10 0  
MCALLEN 59 75 63 84 / 0 10 10 0  
RIO GRANDE CITY 57 73 62 81 / 0 10 0 0  
SOUTH PADRE ISLAND 67 73 69 76 / 0 10 10 0  
BAYVIEW/PORT ISABEL 61 74 64 78 / 0 10 10 0  
 

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

 
 

 
 
SHORT TERM...56-HALLMAN  
LONG TERM....54-BHM  
AVIATION...56-HALLMAN  
IDSS...65-IRISH  
 
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