669  
FXUS64 KHUN 161456  
AFDHUN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HUNTSVILLE AL  
956 AM CDT MON JUL 16 2018  
   
NEAR TERM
 
(REST OF TODAY)  
ISSUED AT 956 PM CDT MON JUL 16 2018  
 
LARGE SWATH OF RAINFALL/SHOWERS WITH EMBEDDED TSTMS IS CURRENTLY  
MOVING EWD ACROSS NW/N CNTRL AL. SOME OF THIS PRECIP CONTAINS SLOW  
MOVING/BACK BUILDING TORRENTIAL RAINFALL, AND AN AREAL FLOOD WARNING  
HAS BEEN ISSUED FOR NE LAWRENCE COUNTY THIS MORNING. THIS ACTIVITY IS  
ASSOCIATED WITH AN UPPER DISTURBANCE TRAVERSING SEWD OVER THE REGION.  
BASED ON RADAR TRENDS, THIS SWATH SHOULD CONTINUE TO SWEEP ACROSS THE  
REMAINDER OF THE AREA INTO THE EARLY AFTERNOON HRS. WHETHER THERE IS  
ANY REDEVELOPMENT BEHIND THIS PASSING UPPER WAVE LATER THIS AFTERNOON  
IS A LITTLE UNCERTAIN, AS AIRMASS RECOVERY MAY BE TOUGH PROVIDED  
THERE MAY NOT BE MUCH HEATING TIME LEFT. CERTAINLY CAN'T RULE OUT A  
FEW ADDITIONAL SHOWERS/TSTMS INTO THE EVENING PERIOD, BUT THE HIGHER  
CHANCES SHOULD BE ENDING WITH THIS LEAD UPPER DISTURBANCE. AFTERNOON  
TEMPS LIKEWISE MAY HAVE A TOUGH TIME GETTING OUT OF THE MID/UPPER 80S  
IF THE RAIN AND SUBSEQUENT CLOUD COVER DOES NOT DIMINISH OR CLR OUT  
UNTIL LATE THIS AFTERNOON.  
   
SHORT TERM
 
(TONIGHT THROUGH WEDNESDAY)  
ISSUED AT 420 AM CDT MON JUL 16 2018  
 
RAINFALL CHANCES SHOULD LOWER SOME TONIGHT, AS THE BOUNDARY SETTLE  
SLIGHTLY FURTHER SOUTH AND THE ATMOSPHERE GETS WORKED OVER AND MORE  
STABLE. CANNOT RULE OUT SOME SCATTERED SHOWERS OR STORMS THOUGH WITH  
THE BOUNDARY STILL CLOSE TO THE AREA. TYPICAL LOWS IN THE LOWER 70S  
LOOK REASONABLE.  
 
IT LOOKS LIKE ANOTHER FRONT/BOUNDARY SWINGS SOUTHEAST INTO THE AREA  
ON TUESDAY. THIS WILL MAKE FOR A SIMILAR SETUP, BUT MAYBE NOT QUITE  
AS WIDESPREAD IN NATURE. KEPT 50 TO 60 PERCENT CHANCE OF  
SHOWERS/STORMS IN THE FORECAST. PWATS WILL REMAIN OVER 1.9 INCHES, SO  
THE ATMOSPHERE WILL REMAIN VERY SATURATED. THUNDERSTORM THREATS LOOK  
THE SAME, WITH SOME FLASH FLOODING REMAINING POSSIBLE. DAYTIME HIGHS  
MAY BE A TAD WARMER, AS SOME VERY EARLY SUNSHINE MIGHT PEAK THROUGH  
AT TIMES DURING THE MORNING HOURS. HOWEVER, HIGHS SHOULD REMAIN BELOW  
NORMAL, REACHING THE UPPER 80S TO AROUND 91 DEGREES.  
 
MODELS ARE HINTING AT A NOTICEABLY DRIER FORECAST AFTER MIDNIGHT ON  
TUESDAY, AS THE FRONT SWING WELL SOUTH OF THE AREA. AFTER SOME  
SCATTERED EVENING SHOWERS/STORMS LOWERED POP TO ISOLATED AND MAINLY  
SOUTH OF THE TENNESSEE RIVER. LOWS LOOK TO DROP INTO THE 66 TO 70  
DEGREE RANGE ACROSS MUCH OF THE AREA AS NOTICEABLY DRIER AIR PUSHES  
INTO THE REGION BEHIND THE FRONT.  
 
DESPITE FAIRLY ABUNDANT SUNSHINE ON WEDNESDAY, THIS DRIER AND COOLER  
AIR SHOULD MAKE FOR FAIRLY PLEASANT CONDITIONS ON WEDNESDAY AND  
WEDNESDAY NIGHT. HIGHS ON WEDNESDAY SHOULD TOP OUT ONLY 85 TO 90  
DESPITE SUNSHINE, WITH LOWS DROPPING INTO THE MID 60S IN MOST  
LOCATIONS OVERNIGHT.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH SUNDAY)  
ISSUED AT 420 AM CDT MON JUL 16 2018  
 
AN UNSETTLED PATTERN WILL BE REALIZED ACROSS THE GREATER NORTH  
AMERICAN DOMAIN FOR THE LATTER HALF OF THE WEEK AND UPCOMING WEEKEND.  
A REX BLOCK SITUATED ACROSS WESTERN ASIA SHOULD TRANSITION TO AN  
OMEGA LIKE BLOCK THIS WEEKEND. THIS WILL AFFECT THE DEVELOPMENT OF  
DOWNSTREAM SYSTEMS IN THE NORTHERN STREAM, WITH DIFFERENCES BETWEEN  
THE 00Z DETERMINISTIC GFS AND ECMWF BECOMING MORE APPARENT AS WE GO  
FURTHER INTO THE LONG TERM.  
 
A FRONTAL BOUNDARY SOUTH OF THE TENNESSEE VALLEY SHOULD RETURN  
NORTHWARD AS A WARM FRONT DURING THE THURSDAY AND FRIDAY TIMEFRAME.  
GIVEN THIS FRONT, KEPT LOWER END RAIN CHANCES IN FOR THE THU/THU  
NIGHT. A RATHER DEEP LOW FOR THIS TIME OF YEAR (PER THE GFS) SHOULD  
DEVELOP EAST OF THE NORTHERN ROCKIES DURING FRIDAY, WITH THE SYSTEM  
ADVANCING TO THE NORTHEAST DURING THE WEEKEND. THE EC AND GFS  
ENSEMBLE DEPICT A SIMILAR SOLUTION; ALBEIT WEAKER. A STRONGER GFS  
WOULD DRIVE A COLD FRONT EXTENDING SOUTH OF IT ACROSS AREA THIS  
WEEKEND, WHILE THE OTHER SOLUTIONS KEPT IT NORTH OF THE REGION. GIVEN  
IT'S SUMMER TIME, WITH A STRONG SURFACE HIGH PARKED NORTHEAST OF  
BERMUDA (MAINTAINING A SOUTHERLY FLOW OVER THE EASTERN CONUS), OPTED  
MORE TOWARDS THE EC/ENSEMBLE FORECAST. THIS WILL RESULT IN SLIGHTLY  
COOLER THAN SEASONABLE HIGH TEMPERATURES IN THE UPPER 80S (RATHER  
THAN LOW 90S), TAMPED DOWN BY MORE CLOUDS THAN SUN AND RAIN CHANCES.  
LOWS WILL AVERAGE IN THE LOWER 70S. WITH THE FRONT REMAINING NORTH OF  
THE AREA, CHANCES OF RAIN WILL CONTINUE INTO SUNDAY.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 604 AM CDT MON JUL 16 2018  
 
TSRA CONTINUE TO PUSH EAST INTO NORTHWESTERN ALABAMA. EXPECT THIS  
AREA OF TSRA TO PUSH INTO THE KMSL TERMINAL AROUND 1230Z. THEN  
EXPECT THIS TO CONTINUE WITH SOME IFR VSBYS/CIG REDUCTIONS (POSSIBLY  
LOWER AT TIMES) WITH HEAVIER THUNDERSTORM ACTIVITY BETWEEN 14 AND  
18Z. FURTHER EAST AT KHSV, VFR CONDITIONS SHOULD CONTINUE UNTIL  
AROUND 16Z, WHEN -TSRA MOVE INTO THE TERMINAL. LIKELY PREDOMINANTLY  
MVFR CONDITIONS AT KHSV DUE TO EITHER CIGS OR VSBYS EXPECTED 16Z THROUGH  
21Z, WITH A PERIOD BETWEEN 16Z AND 20Z OF HEAVIER THUNDERSTORMS  
LOWERING VSBYS/CIGS INTO THE IFR RANGE (OR LOWER). FOR NOW, HAVE  
PREDOMINANT -TSRA CONDITIONS IN UNTIL JUST BEFORE 21Z. KEPT VCTS IN  
BETWEEN 21Z AND 17/02Z, BUT NOT SURE IF ATMOSPHERE WILL BE TOO  
STABILIZED FOR PREDOMINANT PRECIPITATION CHANCES DURING THIS PERIOD  
AT EITHER TERMINAL. EXPECT LOWER VSBYS TO DEVELOP DUE TO FOG AFTER  
MIDNIGHT AT BOTH TERMINALS WITH PRECIPITATION AND LIGHT WINDS  
EXPECTED OVERNIGHT.  
 

 
   
HUN WATCHES/WARNINGS/ADVISORIES
 
 
AL...NONE.  
TN...NONE.  

 
 

 
 
NEAR TERM...09  
SHORT TERM...KTW  
LONG TERM...RSB  
AVIATION...KTW  
 
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