643  
FXUS64 KJAN 201042 AAA  
AFDJAN  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE JACKSON MS  
542 AM CDT WED JUN 20 2018  
   
UPDATE
 
 
UPDATED FOR 12Z AVIATION DISCUSSION  
 

 
   
AVIATION
 
 
12Z TAF DISCUSSION: SCATTERED -SHRA WL CONTINUE ALONG THE HWY 82  
CORRIDOR THIS MORNING WITH TSRA ACTIVITY INCREASING FROM THE WEST  
THIS AFTN. WIDESPREAD TSRA CAN BE EXPECTED TONIGHT OVER THE NW  
HALF OF THE AREA. AWAY FROM TSRA ACTIVITY, VFR CONDS ARE EXPECTED  
TO PREVAIL THROUGH TONIGHT. /22/  
 

 
   
DISCUSSION
 
 
TODAY AND TONIGHT: LOCAL RADARS STILL HAD A FEW LIGHT SHOWERS  
ALONG AND NORTH OF HIGHWAY 82. THIS ACTIVITY WILL CONTINUE TO LIFT  
NORTH EARLY THIS MORNING AND A LULL IN THE ACTIVITY IS EXPECTED  
BY SUNRISE BEFORE RAIN CHANCES INCREASE FROM THE WEST WITH DAYTIME  
HEATING. INCREASING RAIN CHANCES WILL CONTINUE TONIGHT ESPECIALLY  
OVER THE NORTHWEST HALF OF THE CWA. EARLY MORNING SURFACE ANALYSIS  
HAD 1015MB HIGH CENTERED OVER OUR CWA. EARLY MORNING WATER VAPOR  
IMAGERY/RAP ANALYSIS HAD A 590DAM HIGH CENTERED OVER THE NORTHERN  
GULF JUST SOUTH OF THE FLORIDA PANHANDLE AND A 584DAM LOW CENTERED  
OVER THE SOUTHEAST TEXAS COAST. ALSO NOTED WAS A CLOSED LOW OVER  
THE NORTHERN PLAINS. BOTH THE RIDGING SURFACE AND ALOFT WILL  
WEAKEN OVER OUR CWA THROUGH TONIGHT AS THE CLOSED LOW APPROACHES  
FROM THE NORTHWEST AND THE LOW OVER THE TEXAS COAST WORKS TO  
INCREASE DEEP TROPICAL MOISTURE INTO OUR AREA FROM THE WEST. THIS  
WILL LEAD TO THE DEVELOPMENT OF CONVECTION TODAY THAT WILL BECOME  
WIDESPREAD AND CONTINUE TONIGHT. WARMEST TEMPERATURES AND LOWEST  
POPS WILL BE CARRIED OVER EAST MISSISSIPPI AGAIN TODAY WHERE SITES  
SHOULD REACH THE LOWER 90S. LOWEST POPS TONIGHT WILL BE ACROSS  
OUR SOUTHEAST ZONES. LOCALLY HEAVY RAIN MAY OCCUR WITH THE  
STRONGEST STORMS ACROSS OUR NORTHWEST LATER THIS AFTERNOON AND  
EVENING BUT FLASH FLOODING IS NOT CURRENTLY ANTICIPATED. /22/  
 
THURSDAY INTO FRIDAY: AN UPPER LOW WILL BEGIN TO CUT OFF OVER THE  
MID MISSISSIPPI VALLEY BY THURSDAY MORNING, AS A SURFACE CYCLONE  
OCCLUDES OVER IOWA. DURING THE DAY, THE ATTENDANT COLD FRONT WILL  
PUSH EASTWARD INTO THE MID SOUTH TO ARKLATEX CORRIDOR, APPROACHING  
THE ARKLAMISS DELTA THURSDAY EVENING. AHEAD OF THE FRONT, IN THE  
MOISTURE RICH SUMMERTIME REGIME, CONSIDERABLE COVERAGE OF SHOWERS  
AND SOME THUNDERSTORMS IS EXPECTED EARLY IN THE DAY THURSDAY. THOUGH  
THUNDER IS POSSIBLE, THE EARLY DAY ACTIVITY SEEMS LESS LIKELY TO BE  
PARTICULARLY ROBUST WITH THE LACK OF BENEFACTION FROM INSOLATION.  
HOWEVER, THURSDAY AFTERNOON INTO THE EVENING, NORTHWESTERLY DEEP  
LAYER SHEAR WILL BEGIN TO INCREASE WITH STEEPENING MID LEVEL LAPSE  
RATES CLOSER TO THE UPPER STORM SYSTEM. SOMEWHAT CONTINGENT ON  
SUFFICIENT RECOVERY TIME FOLLOWING ANY EARLIER DAY ACTIVITY,  
REDEVELOPMENT IS POSSIBLE DURING THE EVENING AND PERHAPS OVERNIGHT  
OVER OUR NW SPREADING EASTWARD, WITH GREATER POTENTIAL FOR ISOLATED  
SEVERE STORMS IF SOMETHING DEVELOPS.  
 
AS THE UPPER LEVEL SYSTEM CLOSES OFF, THE FRONT WILL BEGIN TO STALL  
FROM WEST TO EAST ACROSS THE NW/N PORTION OF THE CWA HEADING INTO  
FRIDAY. A SIMILAR REGIME FROM THURSDAY NIGHT WILL REMAIN THROUGH  
FRIDAY, AND ANY CONVECTIVE COMPLEXES THAT DEVELOP SHOULD HAVE  
GREATER POTENTIAL FOR AT LEAST SOME ISOLATED SEVERE STORMS. DAMAGING  
WIND GUSTS WOULD APPEAR TO BE THE GREATEST THREAT, THOUGH GIVEN  
COOLER AIR ALOFT WITH THE UPPER LOW, SEVERE HAIL CAN'T BE RULED OUT.  
WILL ADD MENTION OF A MARGINAL SEVERE THREAT TO THE HWO/GRAPHICS  
WITH THIS MORNING'S FORECAST PACKAGE.  
 
THIS WEEKEND INTO EARLY NEXT WEEK: AS THE UPPER LOW ADVANCES  
NORTHEASTWARD AWAY FROM THE AREA, THE STALLED SURFACE FRONT WILL  
RETREAT NORTH OF THE AREA ON SATURDAY WITH LOW/MID LEVEL RIDGING  
BUILDING WESTWARD ACROSS THE DEEP SOUTH AND NORTHERN GULF INTO EARLY  
NEXT WEEK. THOUGH A RATHER MOIST AIRMASS WILL PERSIST THROUGH MUCH  
OF THIS TIME FRAME, DAILY COVERAGE OF DIURNAL CONVECTION IS EXPECTED  
TO STEADILY DECREASE FROM SOUTH TO NORTH AS WARMER MID LEVEL AIR  
BEGINS TO INCREASINGLY SUPPRESS DEVELOPMENT. OF COURSE, THIS MEANS  
TEMPS WILL EDGE BACK UP TO SLIGHTLY ABOVE NORMAL DURING THIS TIME,  
WITH HEAT INDICES FOLLOWING SUIT AND NUDGING INTO THE TRIPLE DIGITS  
AGAIN. /DL/  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
JACKSON 90 73 86 73 / 43 44 72 35  
MERIDIAN 92 72 88 73 / 29 31 70 29  
VICKSBURG 88 73 86 73 / 46 49 74 33  
HATTIESBURG 92 74 89 72 / 29 21 47 19  
NATCHEZ 88 73 86 72 / 47 45 75 26  
GREENVILLE 87 73 86 72 / 53 86 72 48  
GREENWOOD 88 73 84 72 / 47 82 76 51  
 

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

 
 

 
 
DL/22  
 
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