359  
FXUS64 KJAN 271057 AAA  
AFDJAN  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE JACKSON MS  
557 AM CDT SAT MAY 27 2017  
   
UPDATE
 
 
UPDATED FOR 12Z AVIATION DISCUSSION  
 

 
   
AVIATION
 
 
12Z TAF DISCUSSION:  
MVFR/IFR STRATUS WILL CONTINUE THROUGH THE EARLY MORNING HOURS,  
LIFTING/DISSIPATING BY MID/LATE MORNING. VFR CONDITIONS WILL  
PREVAIL THROUGH THE REMAINDER OF THE DAY AND INTO THE EARLY PART  
OF TONIGHT. S/SW WINDS MAY GUST TO 20-25 KT AT TIMES DURING THE  
DAYTIME HOURS. LATE TONIGHT, STRATUS WILL RETURN WITH CEILINGS  
AGAIN FALLING TO MVFR/IFR LEVELS. A WEAKENING LINE OF TSRA WITH  
GUSTY WINDS MAY REACH THE GLH/GWO/GTR AREA AFTER 08Z SUNDAY  
MORNING. /DL/  
 

 
   
DISCUSSION
 
 
TODAY AND TONIGHT: A WARM DAY IS ON TAP TO KICK OFF THE HOLIDAY  
WEEKEND. AFTER MORNING STRATUS LIFT AND BREAK UP, STRONG WARM/MOST  
SSW LOW LEVEL FLOW, INCREASING INSOLATION, AND RATHER HIGH LOW/MID  
LEVEL HEIGHTS WILL SUPPORT HIGH TEMPS NEAR 90. THE JUXTAPOSITION OF  
HOT CONDITIONS AND HIGH DEWPOINTS IN THE LOW/MID 70S WILL RESULT IN  
HEAT INDICES NEARING THE TRIPLE DIGITS ACROSS MUCH OF THE AREA.  
WE'LL CONTINUE TO HIGHLIGHT THE AREAS WITH THE GREATEST POTENTIAL  
FOR 100-105F APPARENT TEMPS IN THE HWO. WHILE THIS WOULDN'T BE AS  
BIG A DEAL LATER ON IN THE SUMMER, IT IS A HOLIDAY WEEKEND AND  
SOMEWHAT EARLY IN THE SEASON FOR THIS DEGREE OF HEAT STRESS, SO  
WE'LL CONTINUE TO DEVOTE ADDED ATTENTION TO THIS ITEM.  
 
RAIN CHANCES WILL BE RATHER LIMITED THROUGH THE DAY THANKS TO A  
STRONG CAP. SOMEWHAT BETTER RAIN CHANCES ARE EXPECTED OVER THE  
NORTHERN PORTION OF THE AREA LATE TONIGHT AS A CONVECTIVE COMPLEX  
OVER MO/AR SPREADS SOUTHEASTWARD TOWARD THE AREA. THESE STORMS  
WILL LIKELY BE ON A WEAKENING TREND WHEN/IF THEY REACH OUR CWA DUE  
TO DECREASING INSTABILITY AND INCREASING INHIBITION. HOWEVER WITH  
ANY STORMS THAT MAKE IT INTO THE HIGHWAY 82 CORRIDOR, THERE IS  
SOME POTENTIAL THEY WILL STILL BE STRONG ENOUGH TO PRODUCE  
DAMAGING WINDS AND PERHAPS MARGINALLY SEVERE HAIL. WE'LL CONTINUE  
TO HIGHLIGHT THE SEVERE THREAT IN THE HWO AND SPLIT OUT SEPARATE  
GRAPHICS TO DIFFERENTIATE BETWEEN THE LATE TONIGHT/EARLY SUN  
MORNING THREAT AND STORM POTENTIAL OVER THE REMAINDER OF THE  
HOLIDAY WEEKEND. /DL/  
 
SUNDAY THROUGH FRIDAY...IT IS POSSIBLE THAT A DECAYING MCS MIGHT BE  
DROPPING OVER OUR NORTHERN MOST ZONES COME SUNRISE SUNDAY BUT  
OTHERWISE MAIN RAIN CHANCES WILL HOLD OFF UNTIL THE EVENING. SUNDAY  
MORNING WL STILL HAVE A 591DAM HIGH CENTERED OVER THE CENTRAL GULF  
WITH AT LEAST A 1016MB RIDGE NOSING WEST ACROSS SOUTHEAST  
MISSISSIPPI FROM THE EASTERN GULF AS WELL. THIS HIGH PRESSURE  
SURFACE AND ALOFT WILL TRY TO HANG TOUGH OVER OUR CWA WHILE A  
SHORTWAVE TROUGH ASSOCIATED WITH A CLOSED LOW CENTERED OVER  
MANITOBA/ONTARIO OF CANADA, SWINGS EAST SUPPORTING A COLD FRONT THAT  
WILL BE DROPPING TOWARD OUR CWA. OUR SURFACE DEW POINTS WILL BE IN  
THE LOWER 70S SUNDAY MORNING BUT THE PWATS WILL BE LESS THAN AN INCH  
AND A QUARTER OVER OUR CWA EXCEPT OUR WESTERN MOST ZONES. AS THE  
DAY PROGRESSES MOISTURE WILL CONTINUE TO POOL AHEAD OF THE  
APPROACHING COLD FRONT AND THE CAP ASSOCIATED WITH THE HIGH PRESSURE  
OVER THE REGION WILL WEAKEN. EARLY SUNDAY EVENING THE COLD FRONT  
WILL APPROACH OUR NORTHWEST ZONES IN AN ENVIRONMENT WHERE HEIGHTS  
WILL REMAIN RATHER HIGH BUT OUR PWATS WILL BE IN EXCESS OF AN INCH  
AND THREE QUARTERS. MLCAPES ARE PROGGED IN EXCESS OF 2500J/KG WITH 0-  
6KM SHEAR AROUND 40KTS AND MID LEVEL LAPSE RATES AROUND 7.0C/KM TO  
SUPPORT ISOLATED STRONG TO SEVERE STORMS OVER THE NORTHWEST HALF OF  
OUR CWA SUNDAY EVENING INTO MONDAY MORNING. MONDAY THE CLOSED LOW  
WILL STILL BE JUST NORTH OF THE GREAT LAKES REGION WHILE RIDGING  
SURFACE AND ALOFT REMAINS CENTERED TO OUR SOUTHEAST. THE COLD FRONT  
IS EXPECTED TO STALL ACROSS THE CENTRAL PORTIONS OF OUR CWA.  
ALTHOUGH WEAKER ENVIRONMENTAL PARAMETERS ARE EXPECTED, DAYTIME  
HEATING WILL LEAD TO ANOTHER ROUND OF STRONG TO SEVERE STORMS ACROSS  
OUR CWA MONDAY, ESPECIALLY OVER EAST CENTRAL MISSISSIPPI. THE MAIN  
THREAT WITH STORMS SUNDAY AND MONDAY WILL BE DAMAGING STRAIGHT LINE  
WINDS BUT HAIL GREATER THAN QUARTERS AND LOCALLY HEAVY RAINFALL WILL  
ALSO BE POSSIBLE ESPECIALLY SUNDAY EVENING. THE LARGE CLOSED LOW  
WILL LIFT NORTH BACK INTO CANADA VERY SLOWLY TUESDAY AND WEDNESDAY  
AND IT WILL TAKE UNTIL THURSDAY NIGHT BEFORE OUR CWA WILL BE FREE OF  
ITS INFLUENCE. ALTHOUGH THE STALLED FRONTAL BOUNDARY WILL HAVE  
WEAKENED BY TUESDAY, IT WILL REMAIN THE FOCUS FOR DIURNAL  
THUNDERSTORMS EACH DAY THROUGH THURSDAY. THE GFS IS MUCH FARTHER  
NORTHWEST, BUT THE CANADIAN AND ECMWF HAVE A SHORTWAVE TROUGH OVER  
THE SOUTHERN PLAINS FRIDAY THAT WILL HELP INCREASE RAIN CHANCES OVER  
OUR CWA GOING INTO THE WEEKEND. /22/  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
JACKSON 90 72 90 71 / 12 11 20 67  
MERIDIAN 89 72 89 70 / 7 9 14 52  
VICKSBURG 91 73 90 70 / 12 14 24 68  
HATTIESBURG 91 71 91 72 / 12 9 14 27  
NATCHEZ 90 73 89 71 / 12 13 22 53  
GREENVILLE 90 72 85 68 / 14 29 39 70  
GREENWOOD 89 73 86 67 / 14 26 34 69  
 

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

 
 

 
 
DL/22  
 
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