037  
FXUS64 KJAN 251519 AAA  
AFDJAN  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE JACKSON MS  
1019 AM CDT TUE APR 25 2017  
   
..SEVERE STORMS EXPECTED WEDNESDAY NIGHT
 
 
   
UPDATE
 
 
UPDATED FOR MORNING DISCUSSION.  
 

 
   
DISCUSSION
 
 
LATEST SATELITE IMAGERY SHOWED FLAT MEAN RIDGING ACROSS THE  
ARKLAMISS REGION. SURFACE HIGH PRESSURE WAS PROVIDING SUNNY SKIES  
ACROSS THE REGION. TEMPERATURES WERE FROM THE UPPER 60S TO THE  
LOWER 70S LATE THIS MORNING. EXPECT TEMPERATURES TO RISE TO THE  
LOWER 80S FOR THIS AFTERNOON. JUST MADE SLIGHT ADJUSTMENTS TO  
AFTERNOON HIGHS. THE REST OF FORECAST APPEARS TO BE ON TRACK./17/  
 
PRIOR DISCUSSION BELOW:  
 
HIGH WILL SHIFT EAST OF THE FORECAST AREA OVER THE NEXT 24 HOURS.  
WITH A STORM SYSTEM BEGINNING TO TAKE SHAPE AND STRENGTHEN ACROSS  
THE NATION'S MID-SECTION DURING THIS TIME, FLOW ALOFT WILL BECOME  
MORE WEST TO SOUTHWESTERLY THROUGH THE PERIOD. SURFACE WINDS WILL  
BECOME SOUTHERLY AND BE ON THE INCREASE AS THE SURFACE PRESSURE  
GRADIENT BEGINS TO TIGHTEN ACROSS THE CWA. THIS INCREASED  
SOUTHERLY FLOW THROUGH THE ATMOSPHERE WILL RESULT IN MOISTENING,  
AND THUS WARMING, CONDITIONS ACROSS THE FORECAST AREA TODAY AND  
TONIGHT.  
 
SKIES WILL REMAIN MOSTLY SUNNY THIS AFTERNOON, DESPITE SOME HIGH  
CLOUDS BEGINNING TO STREAM IN FROM THE WEST. WINDS WILL AGAIN BE  
SOUTHERLY, AND INCREASE TO BETWEEN 10-15 MPH WITH SOME HIGHER GUSTS  
POSSIBLE. THE AFOREMENTIONED TIGHTER PRESSURE GRADIENT WILL BE MOST  
FELT OVER THE DELTA. HERE, SOUTHERLY WINDS WILL BECOME SUSTAINED  
BETWEEN 15-20 MPH, WITH A FEW GUSTS BETWEEN 25-30 MPH POSSIBLE  
DURING THE AFTERNOON HOURS. OTHERWISE, HIGHS WILL WARM INTO THE LOW  
AND MIDDLE 80S THIS AFTERNOON.  
 
THE WEATHER WILL REMAIN QUIET THROUGH THE OVERNIGHT HOURS.  
INCREASING DEEP MOISTURE WILL RESULT IN INCREASING CLOUDS ACROSS  
MAINLY THE WESTERN HALF OF THE FORECAST AREA THROUGH EARLY WEDNESDAY  
MORNING. LOWS WILL BE A GOOD BIT WARMER AS THEY RANGE FROM THE  
MIDDLE 50S TO THE MIDDLE 60S. /19/  
 
WEDNESDAY THROUGH MONDAY: A DEEPENING NORTHERN STREAM UPPER LEVEL  
TROUGH OVER THE SOUTHERN PLAINS WEDNESDAY WILL TRACK NORTHEAST  
ACROSS THE MID MISSISSIPPI RIVER VALLEY WEDNESDAY NIGHT WHILE  
SUPPORTING A SURFACE LOW THAT WILL SEND A COLD FRONT ACROSS OUR CWA  
WEDNESDAY NIGHT. WAA WL INCREASE SIGNIFICANTLY OVER OUR REGION  
WEDNESDAY AHEAD OF THE APPROACHING COLD FRONT. THIS WILL RESULT IN A  
BREEZY SOUTH WIND ACROSS MUCH OF OUR CWA WITH THE STRONGEST WINDS  
NORTHWEST OF A WINNSBORO LOUISIANA TO GRENADA MISSISSIPPI LINE WHERE  
A WIND ADVISORY WILL LIKELY BE NEEDED FROM AFTERNOON INTO THE  
EVENING. ANOMALOUS MOISTURE IS EXPECTED TO POOL AHEAD OF THE COLD  
FRONT WITH SURFACE DEW POINTS IN THE UPPER 60S AND PWATS IN EXCESS  
OF AN INCH AND A HALF INCH. MODELS STILL SHOW A DECENT CAP OVER OUR  
CWA UNTIL LATE AFTERNOON IN THE WEST JUST AHEAD OF THE COLD FRONT. A  
SQUALL LINE IS EXPECTED TO DEVELOP ALONG AND JUST AHEAD THE COLD  
FRONT AND MOVE INTO OUR WESTERN MOST ZONES BEFORE EVENING. THE  
INITIAL ENVIRONMENT OVER OUR WESTERN ZONES WILL FEATURE MID LEVEL  
LAPSE RATES >7.5C/KM, MLCAPES NEAR 2000J/K, DEEP LAYER SHEAR OF 50-  
55KTS AND 0-3KM HELICITY 200-300M2/S2. THESE CONDITIONS ARE EXPECTED  
TO BECOME LESS FAVORABLE OVER EASTERN MISSISSIPPI TOWARD MORNING. AS  
THE SQUALL LINE PROGRESSES ACROSS OUR CWA, SEVERE STORMS CAPABLE OF  
DAMAGING WIND GUSTS, QUARTER SIZED HAIL AND A TORNADO OR TWO WILL BE  
POSSIBLE. CONSIDERING THE PWATS, LOCALLY HEAVY DOWNPOURS WILL  
ACCOMPANY THE STRONGEST STORMS AS WELL. THE GFS IS A LITTLE FASTER  
BUT CONSENSUS PLACES THE LINE NEAR I-55 BY MIDNIGHT AND SOUTHEAST OF  
I-59 BY 6AM. A WEAK SURFACE HIGH BUT MUCH DRIER AIRMASS WILL MOVE  
OVER OUR CWA THURSDAY IN THE WAKE OF THE FRONT BUT A SECOND  
SHORTWAVE AND ASSOCIATED SURFACE LOW WILL MOVE OVER THE SOUTHERN  
PLAINS AND HELP THE COLD FRONT MOVE BACK NORTH AS A WARM FRONT  
THURSDAY NIGHT. OUR CWA WL BE BACK IN THE WARM SECTOR FRIDAY WITH  
RAIN CHANCES MAINLY ACROSS OUR NORTH NEAR THE FRONT. THE LONGWAVE  
PATTERN STILL LOOKS TO AMPLIFY SHARPLY DURING THE WEEKEND WITH A  
591DAM HIGH DEVELOPING JUST OFF THE COAST OF THE SOUTHEAST STATES  
WHILE A CLOSED LOW DROPS OVER THE SOUTHERN PLAINS SATURDAY.  
STRENGTHENING WAA AHEAD OF THIS SYSTEM LOOKS PRODUCE BREEZY TO WINDY  
CONDITIONS ACROSS OUR CWA AGAIN BY SATURDAY AFTERNOON. MODEL  
CONSENSUS HAS SPED UP THE TIMING OF THIS SYSTEM AND ARE IN BETTER  
AGREEMENT WITH THE POTENTIAL FOR SEVERE THUNDERSTORMS OVER OUR CWA  
SATURDAY NIGHT INTO SUNDAY. IN ADDITION TO SEVERE STORMS, MODELS  
SUGGEST POTENTIAL FOR HEAVY RAINFALL OVER A LARGE PORTION OF OUR  
AREA AS WELL. THIS SYSTEM IS EXPECTED TO SHIFT EAST OF OUR AREA  
SUNDAY NIGHT WITH DRY WEATHER ON MONDAY. /22/  
 

 
   
AVIATION
 
 
12Z TAF DISCUSSION: VFR FLIGHT CATEGORIES WILL PREVAIL AT TAF SITES  
THROUGH THE COURSE OF THE PERIOD. WINDS LATER THIS MORNING WILL  
INCREASE FROM THE SOUTH BETWEEN 8-13 KNOTS, WITH SOME GUSTS  
BETWEEN 13-17 KNOTS POSSIBLE. THE GUSTIER WINDS TODAY WILL BE FELT  
OVER THE DELTA, KGLH AND KGWO. HERE, WINDS WILL BE SUSTAINED  
BETWEEN 13-17 KNOTS, WITH GUSTS NEAR 26 KNOTS POSSIBLE AT TIMES  
THROUGH THE AFTERNOON HOURS. THESE BREEZY CONDITIONS WILL SUBSIDE  
A BIT THROUGH THE EVENING AND OVERNIGHT HOURS. /19/  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
JACKSON 83 60 85 58 / 0 1 5 78  
MERIDIAN 83 56 85 63 / 0 0 3 76  
VICKSBURG 82 63 84 56 / 0 1 13 79  
HATTIESBURG 82 58 86 64 / 0 0 5 76  
NATCHEZ 82 63 83 56 / 0 1 10 78  
GREENVILLE 81 64 81 54 / 0 2 25 82  
GREENWOOD 81 61 82 56 / 0 1 10 80  
 

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

 
 

 
 
17  
 
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