132  
FXUS64 KHUN 040059  
AFDHUN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HUNTSVILLE AL  
759 PM CDT FRI JUL 3 2020  
   
NEAR TERM
 
(TONIGHT)  
ISSUED AT 758 PM CDT FRI JUL 3 2020  
 
SHOWERS AND AN ISOLATED THUNDERSTORMS DEVELOPED THIS AFTERNOON MAINLY  
DUE TO DIURNAL HEATING, BUT ADDITIONAL DEVELOPMENT FORMED ALONG A  
WEAK CONVERGENCE BOUNDARY OVER IN THE CUMBERLAND PLATEAU AND A WEAK  
BOUNDARY JUST ACROSS THE AL/MS LINE. ACTIVITY IS EXPECTED TO DIMINISH  
WITH SUNSET AND CLOUD COVER WILL START TO DECREASE LEAVING SKIES  
MOSTLY CLEAR TONIGHT. COMBINED WITH THE LIGHT WINDS AND MOISTURE IN  
PLACE, PATCHY FOG IS POSSIBLE AGAIN TONIGHT/EARLY TOMORROW MORNING.  
OTHERWISE, TONIGHT WILL FEEL MUCH LIKE LAST NIGHT, HUMID WITH LOWS IN  
THE UPPER 60S TO LOWER 70S. AS FOR THE GRIDS, EXTENDED POPS FOR  
ANOTHER HOUR AND ADJUSTED CLOUD COVER TO ACCOMMODATE CURRENT TRENDS,  
BUT NO MAJOR CHANGES WERE MADE.  
   
SHORT TERM
 
(SATURDAY THROUGH SUNDAY)  
ISSUED AT 255 PM CDT FRI JUL 3 2020  
 
AN AREA OF HIGH PRESSURE JUST TO OUR NORTH WILL CONTINUE TO PROMOTE  
HOT AND HUMID WEATHER FOR INDEPENDENCE DAY (SATURDAY) AS WE WILL  
ONCE AGAIN SEE HIGHS IN THE LOWER 90S WITH HEAT INDEX VALUES CLOSE TO  
THE 100 DEGREE MARK ONCE AGAIN. DO EXPECT SOME SLIGHTLY BETTER  
PROSPECTS FOR DIURNAL CONVECTION IN THE AFTERNOON/EARLY EVENING  
(MAINLY SOUTH OF THE TENNESSEE RIVER), AS A WEAK AREA OF LOW PRESSURE  
ALONG THE GULF COAST AND ITS ASSOCIATED CONVERGENCE BOUNDARY SLOWLY  
NUDGES ITS WAY NORTH. THE BEST FORCING WILL REMAIN WELL TO OUR SOUTH,  
HOWEVER, SO THINK THIS WILL SCATTERED IN NATURE AT BEST AND TIED TO  
THE PEAK HEATING OF THE DAY.  
 
THE AFOREMENTIONED AREA OF LOW PRESSURE AND ASSOCIATED BOUNDARIES  
WILL LIFT CLOSER TO THE I-20 CORRIDOR ON SUNDAY. WITH DEEPER MOISTURE  
AND LOWER CONVECTIVE TEMPERATURES, THINK SCATTERED TO NUMEROUS  
SHOWERS AND STORMS WILL BE MORE COMMON ON SUNDAY. CLOUD COVER WILL  
LIKELY KEEP HIGH TEMPERATURES 2-3 DEGREES LOWER, BUT IT WILL LIKELY  
FEEL WORSE JUST DUE TO THE TROPICAL-LIKE AIR MASS IN PLACE WITH PWATS  
IN EXCESS OF 2". FOR THIS REASON, EXPECT HEAVY RAINFALL AND  
POTENTIALLY SOME VERY LOCALIZED FLOODING CONCERNS TO START TO BE AN  
ISSUE SUNDAY AFTERNOON INTO SUNDAY NIGHT.  
   
LONG TERM
 
(SUNDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 255 PM CDT FRI JUL 3 2020  
 
A "CUT OFF" LOW WILL CONTINUE TO MEANDER NORTH INTO THE TENNESSEE  
VALLEY AND SOUTHERN APPALACHIAN REGION, BRINGING GOOD CHANCES FOR  
WIDESPREAD SHOWERS AND THUNDERSTORMS EACH DAY THROUGH AT LEAST THE  
MIDDLE OF THE WEEK. THIS ACTIVITY WILL LIKELY NOT BE SEVERE OR  
EVEN STRONG IN NATURE. HOWEVER, DUE TO THE TROPICAL AIR MASS (PWATS  
UP TO 2.3") IN PLACE, A SETUP FOR HEAVY RAINFALL AND AT LEAST  
LOCALIZED FLASH FLOODING MAY DEVELOP. EVEN BY JULY STANDARDS THIS  
WILL BE A MOIST ENVIRONMENT, WITH THE AFOREMENTIONED PWATS IN THE  
90-95TH PERCENTILE FOR THIS TIME OF YEAR, PER THE KBMX SOUNDING  
CLIMO. GIVEN THE TRACK OF THIS FEATURE, EXPECT S/SE FLOW TO CONTINUE  
TO ADVECT WARM, MOIST AIR FROM THE GULF INTO THE AREA ON MONDAY, WITH  
SOME WEAK LOW-LEVEL CONVERGENCE AXES THAT WILL ROTATE AROUND THE LOW,  
HELPING TO FOCUS THIS AND INITIATE WIDESPREAD CONVECTION CAPABLE OF  
PRODUCING HEAVY DOWNPOURS DURING THE DAYTIME PERIODS. DUE TO THE  
SLOW-MOVING NATURE OF THIS SYSTEM, THE NBM HAS ALREADY PLACED US IN  
CATEGORICAL POPS MONDAY THROUGH WEDNESDAY AS THERE IS FAIRLY HIGH  
CONFIDENCE OF THIS BEING A WET PERIOD FOR US. GIVEN THE CONVECTIVE  
NATURE OF THIS ACTIVITY, IT WILL BE HARD TO PINPOINT QPF THIS FAR  
OUT, BUT THINK THAT AT LEAST 1-2" OF RAINFALL SEEMS REASONABLE  
DURING A MONDAY TO THURSDAY PERIOD, WITH LOCALLY HIGHER AMOUNTS. THE  
LOW WILL GRADUALLY WEAKEN AS IT SHIFTS NE INTO THE APPALACHIANS AND  
MID- ATLANTIC FINALLY, BY THURSDAY. AS A RESULT, WE SEE A DECREASE IN  
POPS LATE THIS WEEK AS WELL AS A GRADUAL WARMING TREND BY TO NORMAL  
TEMPERATURES (90/70) FOR EARLY TO MID JULY.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 635 PM CDT FRI JUL 3 2020  
 
A FEW SHOWERS WILL BRUSH KMSL DUE TO A BOUNDARY JUST OFF TO THE  
WEST, HOWEVER THIS ACTIVITY WILL DIMINISH WITH SUNSET. WITH LIGHT  
WINDS AND MOSTLY CLEAR SKIES TONIGHT, FOG DEVELOPMENT IS POSSIBLE  
EARLY SATURDAY MORNING REDUCING VIS TO MVFR. KEPT FOG IN AT KHSV AND  
ADDED FOG IN AT KMSL FOR THIS TAF ISSUANCE DUE TO THE SHOWER  
ACTIVITY NEAR THE TERMINAL THIS AFTERNOON. DIURNAL SHOWERS AND  
THUNDERSTORMS ARE EXPECTED ONCE AGAIN SATURDAY AFTERNOON SO INCLUDED  
A PROB30 STARTING AT 19Z.  
 

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

 
 

 
 
NEAR TERM...JMS  
SHORT TERM...AMP.24  
LONG TERM...AMP.24  
AVIATION...JMS  
 
FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE  
AT WEATHER.GOV/HUNTSVILLE.  
 
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