024  
FXUS64 KJAN 250541 AAA  
AFDJAN  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE JACKSON MS  
1241 AM CDT SAT MAR 25 2017  
   
UPDATE
 
 
UPDATED FOR 06Z AVIATION DISCUSSION AND FORECAST DISCUSSION.  
 

 
   
AVIATION
 
 
06Z TAF DISCUSSION:  
 
SCATTERED MVFR CONDITIONS ARE EXPECTED TONIGHT THROUGH THE DAY  
TOMORROW DUE TO CEILING WITH SOUTH WINDS REMAINING SUSTAINED AT 10  
TO 20 MPH AND OCCASIONAL GUSTS UP TO 30 MPH THROUGH THE DAY  
TOMORROW. THIS IS ALL IN ADVANCE OF A LINE OF SHOWERS AND STORMS  
PUSHING TOWARD GLH/GWO BY 2 TO 4 AM CDT. OF COURSE VERY GUSTY  
WINDS AND TEMPORARY IFR CONDITIONS ARE EXPECTED IN THE MIDST OF  
ANY THUNDERSTORMS. EXPECT THIS BAND OF THUNDERSTORMS TO WEAKEN  
TOWARD DAYBREAK AS IT PUSHES THROUGH JAN/HKS AND THEN PERHAPS  
STRENGTHEN AGAIN BY MIDDAY TO AFTERNOON AS IT MOVES THROUGH THE  
GTR/CBM/NMM/MEI/PIB/HBG CORRIDOR. IN ADDITION, ADDITION STORMS  
COULD FORM BY MIDDAY AFTERNOON NEAR THE I-55 CORRIDOR WITH THIS  
ACTIVITY ADVANCING EAST LATE AFTERNOON INTO THE EVENING HOURS.  
THERE IS SOME CHANCE LOCATIONS IN EASTERN AND SOUTHEASTERN MS  
COULD BE DEALING WITH MVFR OR WORSE CONDITIONS AND A FEW ROUNDS OF  
THUNDERSTORMS THROUGH THE DAY TOMORROW. /BB/  
 

 
   
DISCUSSION
 
 
LATE EVENING UPDATE:  
 
SEVERE THUNDERSTORM WATCH #84 HAS JUST BEEN ISSUED FOR WESTERN  
PORTIONS OF THE REGION (MAINLY WEST OF THE INTERSTATE 55 CORRIDOR  
THROUGH THE OVERNIGHT (UNTIL 6 AM CDT). CONVECTION ABOUT TO MOVE  
INTO FAR WESTERN ZONES HAS PREVIOUSLY BEEN RESPONSIBLE FOR QUITE A  
FEW TORNADO WARNINGS TO OUR WEST, BUT INGREDIENTS FOR SEVERE  
WEATHER WILL BE IN INCREASINGLY LESSER SUPPLY THE FURTHER EAST  
INTO OUR REGION THE THUNDERSTORMS PROGRESS. STILL, THINKING IS  
THERE WILL BE ENOUGH INSTABILITY AND SHEAR TO PROMPT SOME SEVERE  
THUNDERSTORMS IN THE WATCH AREA AND EVEN THOUGH THE WATCH IS NOT A  
TORNADO WATCH, A TORNADO CANNOT BE RULED OUT WITH THE STRONGEST  
ACTIVITY IN THE MAINLY OUR FAR WEST. ANTICIPATING THAT A GOOD  
PORTION OF THE WATCH WILL BE ABLE TO BE CANCELED BEFORE WATCH  
EXPIRATION AS CONVECTION CLEARS THE AREA. /BB/  
 
PREVIOUS EVENING UPDATE:  
 
STORMS HAVE DEVELOPED ACROSS THE ARKLATEX THIS EVENING AND WITHIN  
THE LAST HOUR OR SO HAVE TAKEN ON MORE OF A SEVERE NATURE. AT  
THIS TIME, HAIL AND WIND APPEAR TO BE THE MAIN CONCERN WITH THESE  
STORMS. NOT MUCH SEEMS TO HAVE CHANGED WITH THE THINKING FOR THESE  
STORMS THROUGH THE EVENING HOURS. HI-RES GUIDANCE CONTINUES TO  
INDICATE THAT THIS BROKEN LINE OF STORMS WILL REACH THE WESTERN  
PART OF MY FORECAST AREA BY AROUND MIDNIGHT AND TRACK EAST THROUGH  
THE NIGHT. WEAKENING SEEMS LIKELY STILL AS IT DOES, BUT HOW  
QUICKLY WILL THAT OCCUR REMAINS THE QUESTION. MESOANALYSIS  
INDICATES MANY OF THE BETTER PARAMETERS WILL BE TO OUR WEST OR IN  
THE WESTERN PART OF MY FORECAST AREA, WHICH SEEMS CONSISTENT WITH  
PREVIOUS THINKING AS WELL. THE OOZ KJAN SOUNDING INDICATES A  
RATHER DRY AIRMASS DESPITE OUR GUSTY SOUTHERLY WINDS THAT CONTINUE  
THIS EVENING. GOING HAZARD OUTLOOK STILL LOOKS DECENT WITH THE  
BEST POTENTIAL FOR ANY SEVERE STORMS BEING IN THE WESTERN PART OF  
THE FORECAST AREA FROM AROUND 11PM/MIDNIGHT THROUGH THE EARLY  
MORNING HOURS. EXPECT GUSTY SOUTHERLY WINDS TO CONTINUE AHEAD OF  
THESE STORMS AS MILD TEMPERATURES SHOULD HOLD THROUGH THE NIGHT.  
/28/  
 
PRIOR DISCUSSION BELOW:  
 
TONIGHT THROUGH SATURDAY,  
 
STRONG MIXING IS RESULTING IN GUSTY SOUTHERLY WINDS AND ENOUGH  
DESTABILIZATION OCCURRED TODAY TO SUPPORT A FEW SHOWERS IN THE  
CAPPED AIRMASS. FORECAST THINKING IS GENERALLY THE SAME CONCERNING  
THE SEVERE WEATHER POTENTIAL FOR LATE TONIGHT AND AGAIN SATURDAY. A  
QUASI LINEAR CONVECTIVE SYSTEM (QLCS) WILL DEVELOP OVER THE ARKLATEX  
REGION AND MOVE INTO WESTERN PORTIONS OF THE ARKLAMISS AROUND  
MIDNIGHT AND EAST OF THE MS RIVER DURING THE PREDAWN HOURS. WITH 0-3  
KM SOUTHWESTERLY SHEAR VECTORS IN THE 40-50 KT RANGE AND SOMEWHAT  
ORTHOGONAL TO THE ROUGHLY NORTH-SOUTH ORIENTED QLCS, THERE IS STILL  
A POTENTIAL FOR MESOVORTICES PRODUCING TORNADOES AND DAMAGING WIND  
GUSTS. THIS THREAT SEEMS GREATEST OVER THE DELTA REGION WITH A  
DIMINISHING THREAT TOWARD DAYBREAK ALONG THE I-55 CORRIDOR.  
 
AS WE GO INTO SATURDAY, THE INITIAL SQUALL LINE SHOULD DISSIPATE  
EARLY IN THE MORNING AS IT MOVES AWAY FROM BETTER SUPPORT AND INTO A  
STOUT MID LEVEL RIDGE CENTERED OVER THE SOUTHEAST CONUS. ADDITIONAL  
CYCLONIC VORTICITY ADVECTION AND UPSTREAM DESTABILIZATION WILL HELP  
TO PRODUCE ANOTHER ROUND OF ORGANIZED STORMS FROM LATE MORNING  
THROUGH THE AFTERNOON. LOW LEVEL SHEAR WILL NOT BE AS STRONG, BUT  
WILL MONITOR THE POTENTIAL FOR A TORNADO GIVEN 0-1KM SHEAR VECTORS  
NEAR THE 20KT THRESHOLD AND PERHAPS BETTER ORIENTATION OF 0-3 KM  
SHEAR VECTORS. OTHERWISE, DAMAGING WIND GUSTS/HAIL ARE EXPECTED TO  
BE THE MAIN CONCERNS WITH STEEP MID LEVEL LAPSE RATES (VT  
APPROACHING 30) PRODUCING MIXED LAYER CAPE > 1000 J/KG. THE GREATER  
THREAT FOR SEVERE WEATHER SATURDAY IS EXPECTED ALONG/EAST OF THE I-  
55 CORRIDOR IN CONTRAST TO TONIGHT. /EC/  
 
TOMORROW NIGHT AND SUNDAY  
 
EXPECTING MUCH OF THE SEVERE TO BE OVER SHORTLY AFTER SUNSET WITH  
A FEW SHOWERS LINGERING IN THE EAST THROUGH MIDNIGHT. THE LATEST  
NAM SUGGESTS THERE MAY BE SOME ISOLATED CONVECTION THROUGH SUNDAY  
AFTERNOON. THE ARW IS A LITTLE SLOWER THAN THE GFS BUT STILL  
SHOWS THE RAIN MOVING OUT. WILL LEAVE THE AREA DRY AT THIS POINT  
FOR SUNDAY.  
 
SUNDAY NIGHT THROUGH TUESDAY  
 
ROUND TWO OF SEVERE APPROACHES LATE SUNDAY NIGHT. IT  
LOOKS LIKE THERE MAY BE SOME STORMS APPROACHING THE RIVER BY 12Z  
MONDAY. INSTABILITY IS ON THE RISE AT THAT TIME, BUT SEEMS TO  
PEAK AFTER 15Z. THE ENTIRE AREA HAS BEEN CHANGED TO A SLIGHT RISK  
OF SEVERE MONDAY. THE LATEST RUNS SHOW SOME DIFFERENCE IN THE  
SPEED OF THE SYSTEM AND SEVERE COULD GET STARTED EARLY. FORECAST  
SOUNDINGS DID NOT SHOW MUCH 0-6 KM SHEER, BUT THE WIND PROFILE  
LOOKS GOOD. COULD SEE CONDITIONS SIMILAR TO TODAY WITH GRADIENT  
WINDS AROUND 30, 40KTS AT 850 AND AROUND 50KT AT 500. THE SURFACE  
LOW WITH THE SYSTEM ON MONDAY TRACKS NORTHEAST ACROSS THE  
ARKANSAS, SO FOR NOW AREAS NORTH OF I20 AND WEST OF I55 MAY SEE  
SOME OF THE BIGGER HAIL. LAPSE RATES SUPPORT SIGNIFICANT HAIL  
SIZES, SO VALUES MUCH LARGER THAN QUARTERS ARE LIKELY. THE  
POSITION OF THE UPPER JET MAY BE LINED UP WITH THE SURFACE LOW AS  
IT PASSES THROUGH THE DELTA MONDAY MORNING, SO THE POTENTIAL FOR  
GOOD UPDRAFTS AND LARGE HAIL WILL BE THERE. CONDITIONS CONTINUE TO  
SUPPORT SEVERE STORMS. STORMS MOVE OUT MONDAY EVENING, BUT MODELS  
SUGGEST THE TAIL END OF THE BOUNDARY STALLS ALONG THE COAST.  
WHILE IT LOOKS THE AREA WILL BE DRY FOR TUESDAY, A FEW SHOWERS  
CAN NOT BE TOTALLY RULED OUT AT THE WARM FRONT DRIFTS NORTH  
THROUGH THE DAY.  
 
WEDNESDAY THROUGH SATURDAY  
WHILE THIS IS NEARLY A WEEK AWAY, THE POTENTIAL FOR FOR ROUND 3  
OF SEVERE STORMS EXISTS FOR LATE WEDNESDAY THROUGH THURSDAY OF  
NEXT WEEK. A CLOSED UPPER LOW AND DEEPENING SURFACE LOW MOVE  
THROUGH THE DELTA AGAIN. THE UPPER TROUGH WILL BE PRETTY FAR  
SOUTH, TAPPING SOME MUCH WARMER AIR AND GOOD MOISTURE FROM THE  
GULF. THE SYSTEM IS WORTH WATCHING. WARMER THAN NORMAL CONDITIONS  
WILL CONTINUE THROUGH THE WEEK.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
JACKSON 59 81 62 79 / 42 8 12 70  
MERIDIAN 60 81 61 78 / 55 9 9 70  
VICKSBURG 58 81 63 78 / 16 4 18 73  
HATTIESBURG 62 82 62 80 / 39 9 10 56  
NATCHEZ 59 82 64 79 / 23 6 13 62  
GREENVILLE 55 78 62 77 / 9 3 23 72  
GREENWOOD 58 79 61 78 / 23 5 19 67  
 

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

 
 

 
 
BB/28/EC/07  
 
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