454  
FXUS64 KSHV 162108  
AFDSHV  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SHREVEPORT LA  
408 PM CDT TUE JUL 16 2019  
   
SHORT TERM
 
/TONIGHT THROUGH WEDNESDAY NIGHT/  
 
THE CENTER OF POST-TROPICAL CYCLONE BARRY CONTINUES TO MOVE  
NORTHEAST INTO THE OHIO RIVER VALLEY. THE HEAVY RAINFALL THAT  
DEVELOPED LAST NIGHT AND CONTINUED THROUGH MUCH OF THIS MORNING  
OVER SOUTHWEST ARKANSAS HAS LARGELY DIMINISHED AND EXITED THE  
AREA, WHILE MORE SCATTERED CONVECTION CONTINUES ACROSS DEEP EAST  
TEXAS AND CENTRAL LOUISIANA. THIS REMAINING ACTIVITY SHOULD WEAKEN  
THIS EVENING AND GRADUALLY END WITH THE LOSS OF DIURNAL  
INSTABILITY. SINCE THE THREAT OF ADDITIONAL HEAVY RAINFALL HAS  
LARGELY COME TO AN END, THE FLASH FLOOD WATCH FOR PORTIONS OF  
SOUTHWEST ARKANSAS WAS CANCELLED.  
 
A BUILDING UPPER RIDGE OVER THE SOUTHEAST CONUS AND A SURFACE HIGH  
OVER THE NORTHEAST GULF OF MEXICO WILL QUICKLY ASSERT THEMSELVES  
BEGINNING ON WEDNESDAY LEADING TO A RETURN OF MOSTLY DRY WEATHER  
TO THE REGION. VERY ISOLATED CONVECTION COULD OCCUR WITH THE SEA  
BREEZE DURING PEAK DAYTIME HEATING WEDNESDAY, BUT COVERAGE WILL BE  
VERY SPOTTY.  
 
UNDER THE INFLUENCE OF STRONG RIDGING, THE HEAT WILL ALSO BUILD.  
THE HIGH AMOUNTS OF LOW-LEVEL MOISTURE SHOULD KEEP DAYTIME HIGH  
TEMPERATURES IN THE MID 90S. ON THE FLIP SIDE, THIS WILL ALSO  
RESULT IN HEAT INDEX VALUES VERY CLOSE TO 105 DEGREES F AND  
FLIRTING WITH HEAT ADVISORY CRITERIA FOR MUCH OF THE AREA.  
HUMIDITY LEVELS COULD BE LOCALLY ENHANCED BY EVAPORATION IN  
PORTIONS OF SOUTHWEST ARKANSAS ON WEDNESDAY DUE TO THE VERY WET  
SOILS AND SEVERE FLOODING THAT OCCURRED TODAY. THUS, I WOULD NOT  
BE SURPRISED TO SEE VERY ISOLATED INSTANCES OF HEAT INDEX VALUES  
WELL ABOVE 105 DEGREES F IN THESE AREAS. HOWEVER, DUE TO THE  
UNCERTAINTY AND HOW BORDERLINE HEAT INDEX VALUES ARE EXPECTED TO  
BE FOR THE MAJORITY OF THE FORECAST AREA, A HEAT ADVISORY WAS NOT  
ISSUED FOR WEDNESDAY.  
 
CN  
   
LONG TERM
 
/THURSDAY THROUGH TUESDAY/  
 
UPPER RIDGING OVER THE SRN PLAINS AND LOWER MS VALLEY WILL CONTINUE  
TO BUILD E INTO THE TN VALLEY AND SE CONUS THURSDAY THROUGH  
SATURDAY, MAINTAINING HOT AND DRY CONDITIONS AREAWIDE, WITH ANY WEAK  
SEABREEZE EXPECTED TO REMAIN TO THE S OF S LA. HAVE TRENDED MAX  
TEMPS A BIT ABOVE THE BLENDED GUIDANCE FOR THIS PERIOD OF THE  
EXTENDED, ALTHOUGH HEAT INDICES WILL RANGE FROM 100-105 DEGREES EACH  
DAY, AND WILL BE HIGHLY DEPENDING ON THE EXTENT OF MIXING OBSERVED  
EACH DAY. THOSE AREAS OF SW AR WHICH OBSERVED EXCESSIVE RAINFALL  
AMOUNTS OF 6-10+ INCHES EARLIER THIS MORNING, AS WELL AS PORTIONS OF  
NCNTRL LA, WILL HAVE TO BE WATCHED CLOSELY SHOULD THE MIXING OF  
DEWPOINTS NOT BE SUFFICIENT ENOUGH TO KEEP HEAT INDICES BELOW THE  
105 DEGREE ADVISORY CRITERIA. THE MEDIUM RANGE PROGS CONTINUE TO  
INDICATE THAT A PORTION OF BARRY'S REMNANTS WILL BE PINCHED OFF FROM  
ITS ORIGINAL TROUGH AXIS ALONG THE E COAST FRIDAY MORNING, WITH THE  
UPPER RIDGING RETROGRADING THIS PIECE OF ENERGY BACK W ACROSS THE SE  
CONUS FRIDAY/SATURDAY AND INTO THE LOWER MS VALLEY SUNDAY (MUCH LIKE  
HOW IT BEGAN A WEEK AND A HALF AGO, EXCEPT FARTHER S INTO THE NRN  
GULF). THUS, ISOLATED CONVECTION WILL BE POSSIBLE SATURDAY AFTERNOON  
OVER THE SRN AND ERN ZONES, WITH THE POTENTIAL FOR CONVECTION  
SPREADING FARTHER W ACROSS N LA SUNDAY. HAVE EXPANDED LOW  
CHANCE/SLIGHT CHANCE POPS FARTHER W SUNDAY, WITH MUCH OF THE  
CONVECTION REMAINING DIURNALLY DRIVEN, DIMINISHING BY EARLY EVENING  
WITH THE LOSS OF HEATING.  
 
THIS INVERTED TROUGH IS PROGGED TO SHIFT FARTHER W INTO SE TX/N LA  
MONDAY, WHICH SHOULD FOCUS MORE IN THE WAY OF SCT CONVECTION OVER  
MUCH OF THE REGION THROUGH TUESDAY AS THIS WEAK TROUGH LINGERS ALONG  
THE ERN PERIPHERY OF THE UPPER RIDGE ONCE IT RETREATS W BACK INTO  
THE PLAINS. WHILE THE ECMWF MAINTAINS STRONGER RIDGING ALOFT EARLY  
NEXT WEEK, THE GFS REMAINS A BIT WEAKER WITH THE RIDGE, ALLOWING FOR  
A LONGWAVE TROUGH TO DIG SE ACROSS THE OH VALLEY/SE CONUS. THIS MAY  
ALLOW FOR A WEAK SFC FRONT TO MIX S EARLY NEXT WEEK AS WELL, WHICH  
MAY ALSO HELP FOCUS SCT CONVECTION THROUGH THE END OF THE EXTENDED  
PERIOD AS WELL. FOR NOW, HAVE MAINTAINED LOW CHANCE POPS UNTIL  
BETTER TIMING/EXTENT OF CONVECTION IS SEEN IN THE MEDIUM RANGE  
PROGS.  
 
15  
 

 
   
PREV DISCUSSION
 
/ISSUED 1246 PM CDT TUE JUL 16 2019/  
 
AVIATION...  
FOR THE 16/18Z TAFS, THE MAJORITY OF THE HEAVY CONVECTION THAT  
HAS PERSISTED ACROSS SOUTHWEST ARKANSAS SINCE LAST NIGHT IS SLOWLY  
LIFTING NORTHEAST OUT OF THE AREA. SOME IMPACTS WILL STILL  
CONTINUE FOR A FEW MORE HOURS ACROSS SOUTHWEST ARKANSAS, INCLUDING  
KELD. MORE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE ALSO  
AFFECTING KMLU AND PORTIONS OF NORTH CENTRAL LOUISIANA. MOST OF  
THE CONVECTION SHOULD END AT ALL SITES AROUND 17/00Z OR 17/01Z. A  
DEEP, MOIST, LOW-LEVEL SOUTHERLY FLOW SHOULD RESULT IN LOW CLOUDS,  
FOG, AND MVFR/IFR CEILINGS AND VISIBILITIES AT MOST TERMINALS  
BETWEEN 17/06Z AND 17/15Z. FLIGHT CONDITIONS SHOULD RAPIDLY  
IMPROVE BACK INTO THE VFR RANGE LATE IN THE PERIOD.  
 
CN  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
SHV 77 95 75 94 / 20 10 0 0  
MLU 74 93 75 93 / 30 10 0 10  
DEQ 74 94 74 93 / 20 0 0 0  
TXK 76 94 75 93 / 20 0 0 0  
ELD 76 93 75 93 / 30 10 0 0  
TYR 76 95 76 94 / 0 0 0 0  
GGG 76 95 76 94 / 10 0 0 0  
LFK 77 95 75 94 / 20 20 0 10  
 

 
   
SHV WATCHES/WARNINGS/ADVISORIES
 
 
AR...NONE.  
LA...NONE.  
OK...NONE.  
TX...NONE.  

 
 

 
 
09/15  
 
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