261  
FXUS64 KFWD 270433  
AFDFWD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FORT WORTH TX  
1133 PM CDT WED JUL 26 2017  
 
   
AVIATION
 
 
NO CHANGES FROM PREVIOUS TAF ISSUANCE WITH VFR CONDITIONS AND  
SOUTH WINDS EXPECTED THROUGH THURSDAY NIGHT. WHILE STRATUS IS  
EXPECTED TO DEVELOP IN CENTRAL TX AGAIN TONIGHT, LOW LEVEL FLOW  
SHOULD BE TOO WEAK AND VEERED BY MORNING FOR THESE CIGS TO SPREAD  
INTO THE WACO TAF SITE. DIURNAL CUMULUS WILL DEVELOP AGAIN  
THURSDAY AFTERNOON WITH WINDS REMAINING SOUTHERLY AT 10-15 KTS  
WITH AN OCCASIONAL GUST UP TO 20 KTS. LATE THURSDAY NIGHT AND  
FRIDAY MORNING, SOME CONVECTION MAY BE ONGOING NEAR THE RED  
RIVER, BUT DON'T EXPECT ANY ISSUES AT THE TAF SITES WITHIN THE  
CURRENT VALID TAF PERIOD.  
 
-STALLEY  
 

 
 
   
DISCUSSION
 
/ISSUED 352 PM CDT WED JUL 26 2017/  
THE MAIN WEATHER STORY WILL BE ANOTHER COUPLE OF HOT DAYS WITH A  
PATTERN CHANGE ARRIVING THIS WEEKEND. A COLD FRONT WILL BRING A  
CHANCE OF SHOWERS AND STORMS THIS WEEKEND AND SOME COOLER WEATHER  
NEXT WEEK. CONFIDENCE IN THE MODEL GUIDANCE IS VERY LOW NEXT WEEK  
DUE TO BOTH MODEL DISAGREEMENTS AND THE FACT THAT EVERY MODEL  
SOLUTION DEVIATES STRONGLY FROM CLIMATOLOGY.  
 
THE HEAT ADVISORY WILL CONTINUE AS IS THROUGH THURSDAY. ANOTHER  
WARM AND MUGGY NIGHT IS ANTICIPATED TONIGHT WITH LOWS IN THE MID  
70S TO LOWER 80S. THURSDAY LOOKS LIKE IT COULD BE THE HOTTEST DAY  
SO FAR THIS YEAR AS WINDS START THE DAY OUT OF THE SOUTHWEST AS A  
WEAK COLD FRONT PUSHES INTO OKLAHOMA. THESE SOUTHWESTERLY WINDS  
COULD DRY OUT THE LOWER LEVELS DURING THE AFTERNOON WITH DEWPOINTS  
FALLING A FEW DEGREES BELOW WHAT WE'VE SEEN THE LAST COUPLE OF  
AFTERNOONS. ON THE OTHER HAND TEMPERATURES WOULD WARM UP EASILY  
WITH THE DRIER AIR AND SLIGHTLY SUBSIDENT SOUTHWESTERLY FLOW. SO  
NO MATTER HOW YOU CUT IT, IT WILL BE HOT WITH HEAT INDEX VALUES  
AGAIN IN THE 105 TO 110 DEGREE RANGE FOR THE REGION EAST OF HWY  
281. ANY CONVECTION TOMORROW WILL LIKELY REMAIN OUTSIDE OF THE  
CWA, EITHER TO THE SOUTHEAST WHERE GULF MOISTURE IS HIGHER OR  
ACROSS OKLAHOMA NEAR THE WEAK FRONT.  
 
THE COLD FRONT WILL LIKELY REACH THE RED RIVER FRIDAY MORNING AND  
THERE IS A SLIGHT CHANCE OF SOME SHOWERS AND STORMS OVER THE  
NORTHERN ZONES DURING THE DAY FRIDAY. TEMPERATURES WILL AGAIN BE  
HOT AND REACH THE UPPER 90S TO 100 DEGREES FOR MOST AREAS WITH  
HEAT INDICES AGAIN REACHING THE 105 MARK ACROSS THE EASTERN HALF  
OF THE REGION. THE HEAT ADVISORY WILL LIKELY NEED TO BE EXTENDED  
ONE MORE DAY FOR PARTS OF THE CWA, BUT SOME COUNTIES IN THE  
CURRENT ADVISORY MAY BE DISCONTINUED AS CLOUDS MOVE IN FROM THE  
NORTH WITH THE FRONT. THIS DECISION WILL BE LEFT TO LATER SHIFTS.  
 
AS THE UPPER LEVEL HIGH BUILDS IN ACROSS THE WESTERN PART OF THE  
CONTINENT THIS WILL RESULT IN UNUSUALLY STRONG NORTHERLY FLOW  
ACROSS THE MIDWEST. A STRONG UPPER TROUGH AND SPRAWLING SURFACE  
HIGH WILL DROP SOUTH THROUGH THE GREAT LAKES REGION THIS WEEKEND.  
THIS WILL ALL HELP PUSH THE FRONT THROUGH NORTH AND CENTRAL TEXAS  
OVER THE WEEKEND. ALONG THE FRONT AN AXIS OF HIGH PRECIPITABLE  
WATER WILL EXIST WITH VALUES INCREASING TO 2.1 TO 2.2 INCHES.  
WHILE THESE VALUES WOULD BE MUCH HIGHER THAN WHAT WE SAW WITH THE  
LAST FEW RAIN EVENTS, UPPER LEVEL TEMPERATURES WILL ALSO BE MUCH  
WARMER SO INSTABILITY AND MEAN LAYER SATURATION WILL NOT BE AS  
GREAT. STILL THE AIRMASS WILL BE CONDUCIVE FOR SCATTERED  
CONVECTION TO DEVELOP BOTH DURING THE OVERNIGHT HOURS AND DAYTIME  
HOURS. THE HIGH MOISTURE AND SKINNY CAPE PROFILE COULD LEAD TO  
LOCALLY HEAVY RAINFALL, BUT OVERALL THE CONVECTIVE POTENTIAL WILL  
BE LIMITED DUE TO A NOTABLE LACK OF ORGANIZED LIFT. WILL KEEP  
POPS IN THE 20 TO 30 PERCENT RANGE FOR FRIDAY NIGHT AND INTO  
SATURDAY. DRIER AIR WILL MOVE INTO THE REGION FROM THE NORTHEAST  
WITH POPS TAPERING OFF FROM NORTHEAST TO SOUTHWEST SATURDAY NIGHT  
AND SUNDAY.  
 
THIS DRY AIR ACTUALLY PRESENTS A FORECAST DILEMMA IN NEXT WEEK'S  
FORECAST. ON ONE HAND NORTHWEST FLOW ALOFT SETS UP WHICH WOULD  
CERTAINLY OPEN THE DOOR FOR CONVECTION TO MOVE INTO THE REGION  
FROM THE HIGH PLAINS, BUT ON THE OTHER HAND MOST MODELS SHOW A  
LACK OF MOISTURE AND INSTABILITY FOR CONVECTION TO DEVELOP MONDAY  
AND TUESDAY. AT THIS POINT HAVE KEPT POPS IN THE SLIGHT CHANCE  
RANGE MONDAY AND TUESDAY OUT OF RESPECT FOR THE DYNAMIC SETUP WITH  
THE INCLINATION THAT THERE WILL PROBABLY BE ENOUGH HEATING AND  
MOISTURE FOR SOME LOW AMOUNT OF INSTABILITY TO BUILD UP.  
 
BY THE MIDDLE OF NEXT WEEK THE GFS MODEL DIVERGES FROM THE MODEL  
CONSENSUS AND SHOWS THE VERY DRY AIR LINGERING (SURFACE DEWPOINTS  
IN THE 50S) WITH LITTLE OR NO THREAT OF RAIN. THE ECMWF, CANADIAN,  
AND NAEFS ARE INDICATING MORE MOISTURE AVAILABLE AND A REMNANT  
CONVECTIVELY INDUCED VORTICITY LOBE MOVING FROM COLORADO SLOWLY  
INTO TEXAS. THESE MODELS SHOW GENERATION OF WIDESPREAD CONVECTION  
WITH THIS ENERGY ON WEDNESDAY THAT COULD POTENTIALLY BRING  
SIGNIFICANT RAINFALL TO THE REGION. ALL OF THAT WILL HINGE ON THE  
QUALITY OF MOISTURE RETURN BY MIDWEEK AND JUST HOW MUCH DRY AIR  
MOVES INTO THE AREA ON THE WESTERN FRINGE OF THE SURFACE HIGH. FOR  
NOW, IT APPEARS THAT BELOW NORMAL TEMPERATURES ARE A GOOD BET  
REGARDLESS OF WHETHER IT RAINS OR NOT (EITHER DUE TO CONTINUED  
STRONG NORTHEASTERLY LOW LEVEL FLOW PER GFS OR RAIN/CONVECTION PER  
OTHER MODELS). HAVE INDICATED HIGHS IN THE LOW 90S FOR MOST AREAS  
AND INCREASED POPS TO NEAR 40 PERCENT ON WEDNESDAY.  
 
TR.92  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
DALLAS-FT. WORTH 80 101 81 101 80 / 5 5 5 10 20  
WACO 77 101 78 102 79 / 5 5 0 5 10  
PARIS 75 97 77 96 74 / 5 5 20 20 30  
DENTON 77 100 77 99 76 / 5 5 5 20 30  
MCKINNEY 77 98 77 98 75 / 5 5 5 20 30  
DALLAS 81 101 82 101 81 / 5 5 5 10 20  
TERRELL 76 99 77 100 77 / 5 5 5 10 20  
CORSICANA 76 99 78 100 78 / 5 5 0 10 20  
TEMPLE 75 100 76 101 77 / 5 5 0 5 10  
MINERAL WELLS 75 101 76 100 75 / 5 5 5 10 20  
 

 
   
FWD WATCHES/WARNINGS/ADVISORIES
 
 
HEAT ADVISORY UNTIL 8 PM CDT THURSDAY FOR TXZ091>095-102>107-  
117>123-131>135-144>148-157>162-174-175.  
 

 
 

 
 
26/25  
 
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