584  
FXUS64 KJAN 122322  
AFDJAN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE JACKSON MS  
622 PM CDT WED AUG 12 2020  
   
UPDATE
 
 
UPDATED FOR 00Z AVIATION DISCUSSION  
 

 
   
AVIATION
 
 
00Z TAF DISCUSSION:  
SCATTERED STORMS WILL DIMINISH THROUGH THE EVENING BUT ANOTHER  
ROUND WILL MOVE INTO THE REGION, ESPECIALLY THE DELTA, OVERNIGHT  
AND CONTINUE SOUTH AND EAST THROUGH TOMORROW. THIS WILL LIKELY  
AFFECT MOST TAF SITES AND MORE REFINEMENT WILL BE NEEDED IN LATER  
FORECASTS. MVFR OR LOWER CEILINGS/VIS COULD ACCOMPANY STORMS BUT  
VFR EXPECTED OUTSIDE OF STORMS. BETWEEN EARLY MORNING CONVECTION  
AND POTENTIAL FOR MORNING STRATUS TO DEVELOP, MVFR CEILINGS ARE  
POSSIBLE FROM ABOUT 09-15Z ACROSS THE REGION. DEPENDING ON WHERE  
CONVECTION IS, SOME SITES SHOULD IMPROVE TO VFR IN THE LATE  
MORNING OR EARLY AFTERNOON. /28/  
 

 
   
DISCUSSION
 
 
TONIGHT AND THURSDAY: THANKS TO EARLY MORNING CLOUDINESS OVER OUR  
DELTA REGION, LOCAL RADARS WERE QUIET THERE SO FAR THIS AFTERNOON.  
CONVECTION THIS AFTERNOON WAS MOSTLY OCCURING ALONG A MOISTURE AXIS  
ALONG AND JUST EAST OF INTERSTATE 55 AND WAS SLOWLY SPREADING EAST.  
EXPECT THIS ACTIVITY TO CONTINUE INTO EARLY EVENING BEFORE  
DISSIPATING BUT ADDITIONAL CONVECTION WILL DEVELOP THROUGH THE NIGHT  
NORTH OF INTERSTATE 20 AND ESPECIALLY OVER THE DELTA REGION DUE TO  
THE PRESENCE OF THE SHORTWAVE TROUGH. MID AFTERNOON WATER VAPOR  
IMAGERY/RAP ANALYSIS STILL SHOWED A SHORTWAVE TROUGH EXTENDING FROM  
THE MID MISSISSIPPI VALLEY INTO THE LOWER MISSISSIPPI VALLEY. THIS  
FEATURE WILL SLOWLY SHIFT EAST THROUGH THURSDAY AND IS EXPECTED TO  
COMBINE WITH OUR MOIST AIRMASS TO REDEVELOP CONVECTION OVER OUR  
NORTHWEST LATER TONIGHT THAT WILL SPREAD ACROSS MUCH OF THE CWA  
DURING THE DAY THURSDAY. THE STORMS WILL BE SLOW MOVERS AND COULD  
PRODUCE LOCALLY HEAVY RAIN ACROSS THE AREA. THE FOCUS FOR HEAVY RAIN  
THURSDAY WILL SHIFT BACK OVER EAST MISSISSIPPI AGAIN BY AFTERNOON.  
THE RAIN AND ASSOCIATED CLOUD COVER WILL HOLD TEMPERATURES DOWN IN  
THE UPPER 80S TO LOWER 90S. THIS WILL MITIGATE CONCERNS FOR HEAT  
STRESS WITH THE POSSIBLE EXCEPTION OF OUR SOUTHWEST WHERE THE LOWEST  
POPS AND HIGHEST TEMPERATURES ARE EXPECTED. PEAK HEAT INDEX VALUES  
MAY REACH 105F BUT WL NOT INCLUDE MENTION OF THIS IN OUR HWO AT THIS  
TIME. /22/  
   
THURSDAY NIGHT THROUGH TUESDAY NIGHT
 
MID LEVEL TROUGHING WILL  
PREVAIL ACROSS THE AREA THURSDAY NIGHT AND FRIDAY. THIS COMBINED  
WITH PWATS AROUND 1.9-2.1 INCHES OVER MOST OF THE AREA, WILL PROMOTE  
SCATTERED TO NUMEROUS SHOWERS FRIDAY AFTERNOON. HOTTER TEMPERATURES  
ARE EXPECTED ON FRIDAY AND THIS COMBINED WITH HIGH HUMIDITY VALUES,  
WILL CREATE HEAT INDICES AROUND 105 FOR AREAS MAINLY WEST OF I-55. A  
HEAT GRAPHIC IS ALREADY OUT SO WILL CONTINUE TO ADVERTISE THIS. THE  
GLOBAL MODELS SUGGEST THAT THE SHORT WAVE WILL MOVE EAST OF THE AREA  
ON SATURDAY WITH DRIER AIR BUILDING IN. PWATS WILL BE AROUND 1.6-1.8  
INCHES OVER MOST OF THE AREA, BUT STILL AROUND 2.0 INCHES IN THE  
SOUTH, WHERE THE BEST CHANCE FOR AFTERNOON STORMS WILL EXIST.  
 
A WEAK FRONTAL BOUNDARY WILL MOVE SOUTH ACROSS THE AREA SATURDAY  
NIGHT INTO SUNDAY AND THIS WILL MAINLY USHER IN SLIGHTLY DRIER AIR  
FOR SUNDAY. HEAT INDICES WILL CONTINUE TO BE NEAR 105 DEGREES MAINLY  
OVER THE WESTERN HALF OF THE AREA, SO WILL CONTINUE TO ADVERTISE  
THIS IN THE HWO AND GRAPHICASTS. EVEN WITH THE DRIER AIRMASS,  
ISOLATED TO SCATTERED AFTERNOON STORMS WILL BE POSSIBLE SUNDAY  
AFTERNOON. MONDAY AND TUESDAY WILL CONTINUE TO FEATURE ISOLATED TO  
SCATTERED AFTERNOON STORMS AND HIGHS AROUND 90 DEGREES./15/  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
JACKSON 74 89 73 89 / 36 72 39 60  
MERIDIAN 74 90 73 88 / 28 77 46 71  
VICKSBURG 75 91 74 92 / 42 68 28 45  
HATTIESBURG 74 92 74 89 / 24 77 33 71  
NATCHEZ 75 91 74 92 / 31 53 23 50  
GREENVILLE 73 89 72 90 / 75 68 18 32  
GREENWOOD 72 88 71 90 / 69 86 30 42  
 

 
   
JAN WATCHES/WARNINGS/ADVISORIES
 
 
MS...NONE.  
LA...NONE.  
AR...NONE.  
 

 
 

 
 
28  
 
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