869  
FXUS64 KMEG 151147  
AFDMEG  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MEMPHIS TN  
647 AM CDT MON AUG 15 2022  
   
UPDATE
 
 
SEE 12Z AVIATION DISCUSSION BELOW.  
 

 
   
DISCUSSION
 
/ISSUED 345 AM CDT MON AUG 15 2022/  
 
THE SUBTROPICAL RIDGE CONTINUES TO BE A MAJOR PLAYER IN THE  
WEATHER OVER THE WESTERN HALF OF THE CONUS WHILE A COMPLEMENTARY  
TROUGH SITS OVER THE EAST. NORTHWESTERLY FLOW ALOFT CONTINUES TO  
ADVECT SCATTERED MID/HIGH CLOUDS OVER THE MID-SOUTH AND WE EVEN  
HAD A FEW VERY LIGHT RAIN SHOWERS DURING THE EVENING. NOTHING IS  
SHOWING UP ON THE SCOPE AT THIS TIME AND THAT SHOULD CONTINUE  
THROUGH EARLY AFTERNOON. A COLD FRONT EXTENDS WEST-SOUTHWEST FROM  
A SURFACE LOW NEAR LOUISVILLE (KY), TO WALNUT RIDGE (AR), TO  
AROUND SPRINGFIELD (MO).  
 
THIS FRONT WILL MOVE SOUTH INTO THE FORECAST AREA THIS MORNING,  
SETTING UP OVER THE SOUTHERN PERIPHERY OF THE CWA THIS AFTERNOON  
AND EVENING. MOST OF THE AREA WILL REMAIN WELL CAPPED DUE TO THE  
PRESENCE OF A SUBSIDENCE INVERSION AROUND 750 MB. THIS INVERSION  
WILL BE WEAKER FARTHER SOUTH AND, WITH TEMPERATURES CLIMBING INTO  
THE MID 90S ALONG/AHEAD OF THE FRONT, WE MAY GET JUST WARM ENOUGH  
TO BUST THE CAP. SHOULD ANY STORMS DEVELOP, THEY WILL LIKELY BE  
CONCENTRATED ACROSS NORTHEAST MS, MAINLY SOUTH OF OXFORD AND  
TUPELO. REGARDING THE HEAT, HEAT INDEX VALUES EXCEEDING 105F ARE  
EXPECTED SOUTH OF A LINE FROM FORREST CITY, TO BATESVILLE, TO  
HOUSTON. THUS, A HEAT ADVISORY IS IN EFFECT FROM 11 AM TO 7 PM  
TODAY.  
 
INSTABILITY WILL BE QUITE STRONG NEAR OR JUST SOUTH OF TUPELO  
WITH MLCAPE LIKELY TO EXCEED 2500-3000 J/KG. DEEP-LAYER SHEAR MAY  
APPROACH 20 KTS WHICH MAY BE STRONG ENOUGH TO SUPPORT AT LEAST  
LOOSELY-ORGANIZED, MULTICELLULAR CONVECTION. MID-LEVEL DRY AIR  
CONTRIBUTING TO DCAPE NEAR 1000 J/KG AND STEEP 0-3 KM LAPSE RATES  
WILL LEAD TO A POTENTIAL FOR DAMAGING WIND GUSTS WITH THE STRONGER  
CELLS. THAT SAID, THE THREAT AREA IN THE MID-SOUTH IS VERY  
LIMITED TODAY. ANY CONVECTION THAT DEVELOPS SHOULD DISSIPATE OR  
MOVE SOUTH OF THE AREA QUICKLY AFTER SUNSET. BEYOND THESE INITIAL  
CELLS, MOST OF THE OVERNIGHT PERIOD SHOULD BE RATHER QUIET. A FEW  
STORMS COULD ENCROACH ON NORTHEAST AR BY SUNRISE, BUT SCATTERED  
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE AREA THROUGHOUT  
THE DAY. POPS ON TUESDAY ARE GENERALLY 20-40%, MEANING IT MAY BE  
MORE HIT- OR-MISS FOR WHO SEES RAINFALL, WITH RAIN CHANCES  
FAVORING AREAS NORTH OF I-40. WE'LL ALSO SEE A FAIRLY BROAD RANGE  
OF TEMPERATURES, RANGING FROM NEAR 80 DEGREES NEAR THE KY BORDER  
TO THE LOW/MID 90S ACROSS NORTH MS.  
 
A STRONG SHORTWAVE TROUGH WILL DIVING SOUTHEAST INTO THE OH VALLEY  
TUESDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE  
WIDESPREAD AHEAD OF THIS TROUGH AS THE DEEPENING SURFACE LOW OVER  
THE PLAINS LIFTS THE WARM FRONT POLEWARD ACROSS THE OZARKS. STORMS  
ARE EXPECTED TO DEVELOP IN THE VICINITY OF THE 850 MB THERMAL  
GRADIENT WHERE STRONG ISENTROPIC ASCENT (305-310 K LAYER) MAY  
FORCE BANDED CONVECTION. THIS ACTIVITY MAY DEVELOP INITIALLY TO  
OUR NORTHWEST BUT IS EXPECTED TO BUILD SOUTHEAST ALONG THIS  
FRONTAL ZONE WITH THE GREATEST QPF EXPECTED BETWEEN 06-18Z  
WEDNESDAY. LOCALLY HEAVY RAINFALL REMAINS A POSSIBILITY WITH THIS  
SYSTEM. PRECIPITABLE WATER WILL BE NEAR NEAR 2.0" (90TH  
PERCENTILE) AND 850-300 MB WIND VECTORS ROUGHLY PARALLEL TO THE  
FRONTAL BOUNDARY WILL SUPPORT THIS POTENTIAL. RAIN CHANCES WILL  
CONTINUE ON WEDNESDAY NIGHT, WITH THE HEAVIER PRECIPITATION  
EXPECTED OVER NORTH MS BY THIS TIME. AVERAGE RAINFALL TOTALS OF  
0.5-1.5 INCHES ARE LIKELY WITH LOCALIZED AMOUNTS OF 2-3" POSSIBLE.  
 
BY LATE WEEK, THE LONGWAVE TROUGH BEGINS TO RETROGRADE SLIGHTLY  
WESTWARD, PUSHING THE RIDGE TOWARD THE GREAT BASIN. WE REMAIN IN  
NORTHWESTERLY FLOW ALOFT WITH THE STALLED FRONT REMAINING NEAR OUR  
SOUTHERN DOORSTEP. THIS WILL KEEP LOW POPS IN THE FORECAST  
THURSDAY AND FRIDAY, PRIMARILY SOUTH OF I-40. GEOPOTENTIAL  
HEIGHTS AT 500 MB ARE FORECAST TO BE IN THE 10TH PERCENTILE OF  
CLIMATOLOGY, INDICATING THE RARITY OF A TROUGH THIS DEEP IN MID-  
AUGUST. THIS WILL MAINTAIN BELOW-NORMAL TEMPERATURES THROUGH THE  
REMAINDER OF THE FORECAST PERIOD. THE LATEST GLOBAL MODELS ARE ON  
BOARD WITH AN EVENT STRONG TROUGH MOVING ACROSS THE UPPER MIDWEST  
LATE WEEK, EVENTUALLY CLOSING OFF TO OUR NORTH. THIS MAY BRING  
RAIN CHANCES BACK TO THE ENTIRE MID-SOUTH AT SOME POINT OVER THE  
WEEKEND.  
 
MJ  
 

 
   
AVIATION
 
 
12Z TAFS  
 
EXPECT VFR CONDITIONS TO PREVAIL THROUGH THE TAF PERIOD. WINDS  
SHOULD VEER TO THE NORTH THROUGHOUT THE DAY AND PICK UP TO 7-9 KT  
THIS AFTERNOON BEFORE GOING LIGHT AGAIN OVERNIGHT. SPOTTY SHOWERS  
AND THUNDERSTORMS MAY DEVELOP ACROSS PARTS OF NORTH MISSISSIPPI  
AHEAD OF A COLD FRONT TODAY, THUS CARRIED VCTS AT TUP LATE THIS  
AFTERNOON THROUGH THE EARLY EVENING. CONFIDENCE IS LOW ON COVERAGE  
BUT WAS WORTH MENTIONING.  
 
CAD  
 

 
   
MEG WATCHES/WARNINGS/ADVISORIES
 
 
AR...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING  
FOR LEE AR-PHILLIPS-ST. FRANCIS.  
 
MO...NONE.  
MS...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING  
FOR CALHOUN-CHICKASAW-COAHOMA-PANOLA-QUITMAN-TALLAHATCHIE-  
TUNICA-YALOBUSHA.  
 
TN...NONE.  

 
 

 
 
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