231  
FXUS64 KOHX 251159  
AFDOHX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NASHVILLE TN  
659 AM CDT SAT MAR 25 2017  
   
UPDATE
 
 
FOR 12Z AVIATION DISCUSSION.  
 

 
   
DISCUSSION
 
 
THE FIRST WAVE OF TODAY'S SYSTEM CROSSED THE MISSISSIPPI RIVER  
AROUND 08Z THIS MORNING. THE LINE HAS WEAKENED AS IT'S MOVED EAST  
AND SHOULD CONTINUE TO WEAKEN OVER THE NEXT FEW HOURS. THERE ARE  
ALREADY A FEW LIGHT ELEVATED ECHOES SHOWING UP ON RADAR OVER OUR  
SOUTHWESTERN COUNTIES AND WE COULD SEE A FEW MORE SUBSTANTIAL  
SHOWERS CROSS OVER THE TENNESSEE RIVER BEFORE 7AM. WHILE SCATTERED  
SHOWERS AND A FEW THUNDERSTORMS MAY DEVELOP BEFORE 18Z IN OUR  
WESTERN MOST COUNTIES, THE BULK OF TODAY'S ACTIVITY IS EXPECTED IN  
THE AFTERNOON AND EVENING. AS WE BEGIN TO DESTABILIZE THIS  
AFTERNOON WITH MOIST AIR SURGING UP FROM THE SOUTH, WE COULD SEE  
SOME STRONG TO ISOLATED SEVERE STORMS DEVELOP MAINLY WEST OF I-65.  
INSTABILITY DOESN'T LOOK MUCH, IF AT ALL BETTER THAN IT DID  
YESTERDAY, BUT STILL SEEING AROUND 600 TO 700 J/KG OF CAPE  
ACCORDING TO THE NAM, WITH THE GFS ONLY MUSTERING UP ABOUT 300  
J/KG. WE DO STILL HAVE DECENT 0-6KM SHEAR VALUES OF AROUND 30 TO  
40 KNOTS. SO AS THE LOW PRESSURE SWINGS NORTHEAST FROM ARKANSAS  
THROUGH MISSOURI, IT SHOULD PROVIDE ENOUGH FORCING FOR US TO SEE  
STORMS DEVELOP/STRENGTHEN FROM 1PM TO 6PM OVER THE WEST. THE NAM  
IS ALSO SHOWING 0 TO 1 KM HELICITY VALUES AROUND 200 TO 300,  
ALLOWING JUST ENOUGH TURNING IN THE ATMOSPHERE TO MENTION A SMALL  
TORNADO THREAT THIS AFTERNOON. HOWEVER, THE MAIN THREATS WITH ANY  
STORMS THAT DO DEVELOP WILL BE DAMAGING WINDS AND HAIL. IT  
DOESN'T LOOK LIKE THERE WILL BE A WHOLE LOT OF EASTWARD MOVEMENT  
TO THIS AFTERNOON'S WAVE OF STORMS AS THE LOW PRESSURE HEADS  
NORTH. STORMS MAY PASS OVER THE SAME GENERAL AREA AS WE HEAD INTO  
TONIGHT. EXPECT ANY STRONG OR SEVERE ACTIVITY TO DECREASE BY 10PM  
TONIGHT AS WE STABILIZE, BUT SHOWERS WILL LIKELY HANG AROUND  
THROUGHOUT THE OVERNIGHT HOURS. SOUNDINGS INDICATE PWATS OF 1 TO  
1.25 INCHES LASTING THROUGH THE LATE EVENING TONIGHT AND INTO  
MORNING SUNDAY. SOME PLACES MAINLY EAST OF I-65 COULD SEE RAINFALL  
TOTALS OF ONE HALF TO THREE QUARTERS OF AN INCH EARLY SUNDAY  
MORNING.  
 
WE SHOULD SEE A BREAK IN PRECIP ON SUNDAY NIGHT AFTER SHOWERS AND  
A FEW THUNDERSTORMS EXIT THE PLATEAU. THE NEXT SYSTEM ISN'T TOO  
FAR OFF THOUGH. A SHORTWAVE OVER THE CENTRAL PLAINS WILL HEAD EAST  
AND INTO THE MID MISSISSIPPI VALLEY ON MONDAY BRINGING WITH IT A  
CHANCE OF SHOWERS AND THUNDERSTORMS. THE NAM AND GFS BOTH INDICATE  
AT LEAST SLIGHTLY MORE INSTABILITY WITH MONDAY/MONDAY NIGHT'S  
SYSTEM THAN WITH TODAYS, SO WE COULD BE IN STORE FOR ANOTHER ROUND  
OF STRONG TO SEVERE STORMS. RIGHT NOW, THE WESTERN COUNTIES IN  
MIDDLE TENNESSEE ARE UNDER A SLIGHT RISK FOR SEVERE STORMS. STEEP  
MID LEVEL LAPSE RATES AND STRONG WINDS ALOFT WILL MAKE HAIL AND  
DAMAGING WINDS THE MAIN THREATS. THE MAIN TIME FRAME FOR STORMS ON  
MONDAY WILL BE IN THE AFTERNOON AND EARLY EVENING.  
 
PRECIP WILL MOVE OFF TO THE EAST TUESDAY AND LEAVE US WITH A  
QUIET NIGHT, BUT THE ACTIVE PATTERN WILL CONTINUE FOR THE  
REMAINDER OF THE WORK WEEK. AN UPPER LEVEL TROUGH WILL SWING  
ACROSS THE EASTERN PORTION OF THE U.S. WEDNESDAY THROUGH THURSDAY  
BRINGING ALONG ANOTHER CHANCE OF THUNDERSTORMS.  
 
TEMPERATURES WILL REMAIN MILD THROUGHOUT THE FORECAST WITH HIGHS  
IN THE UPPER 60S AND MID 70S AND LOWS IN THE 50S.  
 

 
   
AVIATION
 
 
12Z TAF DISCUSSION.  
 
TIGHT SURFACE LOW HEADING UP INTO/THROUGH THE OHIO VALLEY LATER  
TODAY AND TONIGHT EXPECTED TO BRING SCATTERED PRECIPITATION TO THE  
AREA...MOSTLY IN THE AFTERNOON AND EVENING...ALTHOUGH A FEW  
SHOWERS ARE EXPECTED TO HANG ON OVERNIGHT AS WELL. CIGS ARE NOT  
EXPECTED TO MAKE SIGNIFICANT DROP UNTIL LATE TONIGHT...EXCEPT IN  
MAYBE A PASSING STORM. WIND WILL AGAIN BE QUITE GUSTY TODAY...  
WITH GUSTS REACHING CLOSE TO 30KNTS. WIND SHEAR POSSIBLE THROUGH  
15Z.  
 

 
   
OHX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
DISCUSSION......11  
AVIATION........07  
 
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