217  
FXUS64 KBRO 171722 AAB  
AFDBRO  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
1222 PM CDT TUE OCT 17 2017  
   
DISCUSSION
 
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 

 
   
AVIATION
 
VFR THE NEXT 24 HOURS. HIGH PRESSURE AND DRY AIR WILL  
SPREAD OVER THE AREA, WITH LIGHT WINDS AND MOSTLY CLEAR TO CLEAR  
SKIES THE NEXT 24 HOURS.  
 

 
   
PREV DISCUSSION
 
/ISSUED 623 AM CDT TUE OCT 17 2017/  
 
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 
AVIATION...LIGHT NORTHWEST WINDS AND CLEAR SKIES PREVAIL ACROSS  
DEEP SOUTH TEXAS THIS MORNING. SURFACE HIGH PRESSURE ACROSS THE  
REGION WILL SUPPORT VFR CONDITIONS FOR THE NEXT 24 HOURS. LIGHT  
NORTH WINDS THIS MORNING WILL GRADUALLY BECOME NORTHEAST BY THIS  
EVENING.  
 
PREV DISCUSSION... /ISSUED 420 AM CDT TUE OCT 17 2017/  
 
SHORT TERM (TODAY THROUGH WEDNESDAY): FALL-LIKE WEATHER WILL  
CONTINUE FOR THE NEXT 36 HOURS AS DRY NORTHWEST FLOW ALOFT AND  
SURFACE HIGH PRESSURE PREVAILS ACROSS THE REGION. LIGHT NORTHERLY  
FLOW AT THE SURFACE AND VERY DRY AIR ABOVE 850MB WILL ALLOW  
TEMPERATURES TO REBOUND INTO THE LOW TO MID 80S THIS AFTERNOON.  
SURFACE HIGH PRESSURE MIGRATES TO THE MID-ATLANTIC COAST TONIGHT  
ALLOWING LIGHT ONSHORE FLOW TO RETURN. TEMPERATURES AND DEWPOINTS  
GRADUALLY RECOVER TONIGHT INTO WEDNESDAY WITH THE STEADY ONSHORE  
FLOW. LOW TEMPERATURES TONIGHT WILL BE IN THE 50S, EXCEPT FOR THE  
LOW TO MID 60S AT THE BEACHES. HIGH TEMPERATURES WEDNESDAY WILL  
RANGE FROM THE LOW TO MID 80S NEAR THE COAST TO THE UPPER 80S TO  
AROUND 90 DEGREES ACROSS THE WEST. MEASURED WATER LEVELS CONTINUE  
TO SLOWLY TREND DOWN SINCE HIGH TIDE AT 2:26 AM THIS MORNING,  
THOUGH ARE STILL RUNNING MORE THAN A FOOT ABOVE PREDICTED. THE  
COASTAL FLOOD STATEMENT IN EFFECT UNTIL 5 AM WILL BE ALLOWED TO  
EXPIRE.  
 
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY): A 500 MB TROUGH WILL  
BE DIGGING OVER THE SOUTHWESTERN AND SOUTH CENTRAL STATES AROUND  
MID WEEK. THIS TROUGH WILL MOVE SLOWLY EASTWARD THROUGH THURS AND  
THURS NIGHT WITH MOISTURE VALUES SLOWLY INCREASING OVER MUCH OF TX  
THROUGH THIS PERIOD. ACCORDINGLY THE CONV CHCS WILL GRADUALLY  
INCREASE ON THURS LIKELY PEAKING ON FRI AS THE 500 MB TROUGH AXIS  
CLEARS THE RGV. ANOTHER LARGER 500 MB TROUGH AXIS WILL THEN DIG  
ACROSS THE WESTERN STATES AND THE ROCKIES LATER THIS WEEK PUSHING  
INTO TX LATE SAT/EARLY SUN. AS THIS TROUGH CLEARS THROUGH THE  
REGION SUN IT WILL USHER ANOTHER COLD FRONT THROUGH THE RGV. ONCE  
AGAIN SOME BETTER MOISTURE VALUES POOL OVER THE RGV JUST AHEAD OF  
2ND 500 MB TROUGH PASSAGE. SO EXPECT THE CONV POTENTIAL TO SPIKE  
ONCE AGAIN ON SUNDAY. 500 MB RIDGING WILL THEN PREVAIL NEXT MON  
AND TUES RESULTING IN FAIRLY WARM TEMPS AND LOW POPS.  
 
ALTHOUGH THE GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT IN THE  
HANDLING OF THE 500 MB PATTERN THROUGH DAY 7, BIGGER DISAGREEMENTS  
ARE SHOWING UP BETWEEN THE TWO LONGER RANGE MODEL SETS CONCERNING  
POPS. THE GFS IS GOING WITH A DRIER FORECAST MAINLY AFTER FRI WITH  
THE ECMWF HOLDING ONTO HIGHER POPS ON THROUGH SUN. THE ECMWF HAS  
SHOWN BETTER RUN TO RUN CONSISTENCY FOR THE CONV POTENTIAL WITH  
THE GFS SHOWING MORE VOLATILITY FOR POPS IN RECENT RUNS. SO WILL  
LEAN CLOSER TO THE WETTER ECMWF NUMBERS.  
 
THE ECMWF AND GFS TEMPS ARE IN GOOD AGREEMENT THROUGH DAY 7 AND  
WILL GO CLOSE TO A BLEND OF THESE TWO MODELS FOR MAXES AND MINS.  
 
DESPITE THE INCREASING DISAGREEMENT IN THE POPS BETWEEN THE GFS  
AND THE ECMWF, OVERALL CONFIDENCE IN THE LONGER RANGE FORECAST  
PERIOD WORDING REMAINS ABOVE AVERAGE.  
 
MARINE (NOW THROUGH WEDNESDAY): MARINE CONDITIONS WILL CONTINUE TO  
IMPROVE ALONG THE LOWER TEXAS COAST THROUGH THE PERIOD. SMALL CRAFT  
EXERCISE CAUTION CONDITIONS WILL LINGER ON THE GULF WATERS 20 TO 60  
NM EAST OF PADRE ISLAND THROUGH EARLY THIS AFTERNOON. MORE FAVORABLE  
MARINE CONDITIONS DEVELOP ON THE GULF WATERS BY TONIGHT WITH LIGHT  
TO OCCASIONAL MODERATE NORTHEAST TO EAST WINDS AND SEAS OF 3 TO 4  
FT.  
 
WEDNESDAY NIGHT THROUGH SATURDAY NIGHT: SURFACE RIDGING SETTLING  
OVER THE SOUTHEASTERN AND EASTERN STATES WILL MAINTAIN A MODERATE  
EAST TO SOUTHEAST LOW LEVEL FLOW OVER THE LOWER TX BAY AND GULF  
WATERS THROUGH SAT NIGHT. THE GULF SWELLS MAY BRIEFLY PUSH UP TO  
SCEC OR MARGINAL SCA CONDITIONS LATE THURS INTO FRI AS THE SURFACE  
WINDS OFFSHORE EDGE UP A BIT. HOWEVER OVERALL THE BAY AND GULF  
CONDITIONS SHOULD REMAIN BELOW SCA CRITERIA FOR MOST OF THE LONGER  
RANGE PERIOD.  
 

 
   
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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