689  
FXUS64 KMEG 301140 AAA  
AFDMEG  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MEMPHIS TN  
640 AM CDT SUN APR 30 2017  
   
UPDATE
 
 
UPDATED FOR 12Z AVIATION FORECAST DISCUSSION BELOW.  
 

 
   
PREV DISCUSSION
 
/ISSUED 455 AM CDT SUN APR 30 2017/  
 
DISCUSSION...  
EARLY MORNING GOES WATER VAPOR IMAGERY SHOWED A CLOSED UPPER LOW  
CENTERED OVER WESTERN OK. A DOWNSTREAM PLUME OF TROPICAL MOISTURE  
EXTENDED NORTH THROUGH THE LOWER AND MIDDLE MS RIVER VALLY. AN  
AXIS OF 2 INCH PRECIPITABLE WATER VALUES EXTENDED NORTH UP THE MS  
RIVER DELTA OF THE MIDSOUTH. SEVERAL ROUNDS OF STORMS HAD AFFECTED  
EASTERN AR, THE MO BOOTHEEL AND NORTHWEST TN EARLIER THIS MORNING,  
WITH BOWING SEGMENTS PRODUCING DAMAGING WINDS AND SEVERAL MESOVORTICES  
NOTED ON RADAR. DESPITE THE PROGRESSIVE NATURE OF MOST OF THE STORMS,  
RAINFALL RATES EXCEEDING 5 INCHES PER HOUR HAS RESULTED IN FLASH  
FLOODING.  
 
RAPID UPDATE CONVECTION-ALLOWING SHORT TERM MODELS HAVE STRUGGLED  
A BIT WITH TIMING AND LOCATION OF STORMS, AS MESO-LOWS HAVE  
FORMED AND AFFECTED STORM EVOLUTION. EXPECT THIS TREND TO CONTINUE,  
AS STORMS LIFT INTO THE MIDSOUTH FROM THE ARKLAMISS REGION THIS  
MORNING. EVENTUALLY, EXPECTED A WELL-DEFINED BACK SIDE OF THE  
STORMS TO FORM AS THE MIDLEVEL TROF AXIS ROTATES THROUGH. STORMS  
SHOULD REACH THE TN RIVER BY EARLY AFTERNOON.  
 
ALTHOUGH THE STORM TOTAL RAIN AMOUNTS EAST OF THE MS RIVER WILL  
NOT LIKELY BE AS IMPRESSIVE AS OVER EASTERN AR, INTENSE RAINFALL  
RATES WILL STILL LEAD TO HEIGHTENED RISK OF FLASH FLOODING. THE  
FLASH FLOOD WATCH WAS THEREFORE EXPANDED EAST, TO INCLUDE ALL OF  
NORTH MS AND ADDITIONAL AREAS OF WEST TN THROUGH THIS AFTERNOON.  
 
BY MIDEVENING, TRANQUIL WEATHER WILL PREVAIL OVER THE MIDSOUTH,  
WITH A COOL AND MUCH DRIER AIRMASS PREVAILING. FOLLOWING MODEST  
LOW LEVEL MOISTURE RETURN ON TUESDAY, RAIN CHANCES RETURN ON  
WEDNESDAY, ASSOCIATED WITH A DEEPENING NORTHERN BRANCH LOW DROPPING  
INTO THE MIDSOUTH FROM THE CENTRAL PLAINS. TEMPERATURES THROUGH  
LATE WEEK WILL PREVAIL BELOW NORMAL, WITH CLOUDY SKIES AND COLD  
ADVECTION LIMITING LOW LEVEL ATMOSPHERIC INSTABILITY. 00Z GFS  
PROGS 1000-500 MB THICKNESSES OF 543 DM OVER NORTHEAST AR AND THE  
MO BOOTHEEL FRIDAY MORNING - WITH PRECIPITATION. QUITE UNUSUAL FOR  
EARLY MAY.  
 
NEXT WEEKEND SHOULD SEE THE UPPER LOW LIFT OUT, WITH WEAK NORTHWEST  
FLOW ALOFT PREVAILING, DOWNSTREAM OF UPPER RIDGING OVER THE PLAINS.  
 
PWB  
 

 
   
AVIATION
 
 
12Z TAFS  
 
PRIMARY AVIATION WEATHER IMPACTS (MAINLY TS AND ASSOCIATED IFR  
VISIBILITIES) WILL OCCUR WITHIN THE FIRST 6 TO 8 HOURS OF THE  
TAF. FEW CHANGES FROM EARLIER TAF PACKAGE, OTHER THAN TO BACK  
WINDS TO THE E/SE EARLY ON DUE TO A WAKE LOW OVER NORTHWEST AR.  
THIS FEATURE WILL LIFT INTO MO THIS MORNING, WITH PRESSURE  
GRADIENT VEERING WINDS BACK TO THE SYNOPTICALLY- FAVORED SOUTH  
DIRECTION. OVERALL, FOLLOWED THE 10Z HRRR TIMING OF TSRA.  
 
PWB  
 

 
   
MEG WATCHES/WARNINGS/ADVISORIES
 
 
AR...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR CLAY-  
CRAIGHEAD-CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-  
MISSISSIPPI-PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.  
 
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLAY-CRAIGHEAD-  
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-  
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.  
 
MO...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR DUNKLIN-  
PEMISCOT.  
 
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR DUNKLIN-PEMISCOT.  
 
MS...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ALCORN-BENTON MS-  
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-  
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-  
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.  
 
FLASH FLOOD WATCH THROUGH THIS EVENING FOR ALCORN-BENTON MS-  
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-  
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-  
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.  
 
TN...WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON TN-CARROLL-  
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-  
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-  
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.  
 
FLASH FLOOD WATCH THROUGH THIS EVENING FOR CHESTER-CROCKETT-DYER-  
FAYETTE-GIBSON-HARDEMAN-HAYWOOD-LAKE-LAUDERDALE-MADISON-  
MCNAIRY-OBION-SHELBY-TIPTON.  
 

 
 

 
 
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