561  
FXUS64 KHUN 270028  
AFDHUN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HUNTSVILLE AL  
728 PM CDT TUE MAY 26 2020  
   
UPDATE
 
 
FOR 00Z TAFS.  
 

 
   
NEAR TERM
 
(TONIGHT)  
ISSUED AT 245 PM CDT TUE MAY 26 2020  
 
A BROAD AREA OF RAIN SHOWERS CONTINUES TO FILTER ACROSS THE REGION  
FROM THE SOUTH THIS AFTERNOON AS SOUTHERLY FLOW RAMPS UP AHEAD OF A  
BROAD UPPER-LOW OVER THE SOUTHERN PLAINS. INSTABILITY HAS REMAINED  
FAIRLY LIMITED AND GIVEN CURRENT CONVECTIVE TRENDS, THINK THAT WE'LL  
HAVE A HARD TIME SEEING THUNDERSTORMS. STILL, CANNOT RULE OUT AN  
ISOLATED STORM OR TWO IN A NARROW WINDOW BETWEEN 21-03Z AS CONVECTIVE  
TEMPERATURES ARE REACHED, AND HAVE KEPT AN ISOLATED THUNDERSTORM  
MENTION IN THE FORECAST FOR THIS REASON. EXPECT THIS ACTIVITY TO  
CONTINUE INTO THIS EVENING, BEFORE GRADUALLY DISSIPATING AFTER  
MIDNIGHT. STILL, GIVEN THE TROPICAL-LIKE AIR MASS IN PLACE AND A WEAK  
CONVERGENCE AXIS DRAPED NEAR THE AREA, THINK THAT SCATTERED LIGHT  
SHOWERS WILL CONTINUE THROUGH THE NIGHT. MORE NOTABLY, EXPECT LOW  
STRATUS AND POTENTIALLY SOME LIGHT FOG TO DEVELOP IN LOCATIONS THAT  
REMAIN RAIN- FREE THANKS TO THE MOIST BOUNDARY LAYER CONDITIONS.  
THESE CLOUDS WILL MAKE FOR A MILD AND FAIRLY HUMID NIGHT, WITH LOWS  
IN THE MIDDLE 60S.  
   
SHORT TERM
 
(WEDNESDAY THROUGH THURSDAY)  
ISSUED AT 245 PM CDT TUE MAY 26 2020  
 
THE AFOREMENTIONED LOW PRESSURE SYSTEM WILL APPROACH THE LOWER-  
MISSISSIPPI RIVER VALLEY WEDNESDAY INTO THURSDAY, BRINGING NUMEROUS  
TO WIDESPREAD SHOWERS AND THUNDERSTORMS BOTH DAYS. MOSTLY CLOUDY  
CONDITIONS WILL BEGIN THE DAY ON WEDNESDAY, BUT EXPECT A FEW BREAKS  
TO DEVELOP BY THE AFTERNOON, ALLOWING US TO WARM INTO AT LEAST THE  
UPPER 70S. THE MAIN TRIGGER FOR CONVECTION ON WEDNESDAY WILL LIKELY  
BE ALONG ANY WEAK CONVERGENCE BOUNDARIES THAT CAN DEVELOP. THE MAIN  
QUESTION FOR WEDNESDAY WILL BE INSTABILITY AS CLOUD COVER WILL KEEP  
HEATING IN CHECK THROUGH MIDDAY. HOWEVER, AS A MID-LEVEL JET STREAK  
ROTATES INTO SOUTH AND CENTRAL ALABAMA MAY PROVIDE THE NECESSARY  
LIFT TO GENERATE SOME DEEPER CONVECTION TO OUR SOUTH AND WEST AS IT  
TAPS INTO THE INSTABILITY ALOFT BY 18Z. THIS ACTIVITY SHOULD MAKE  
ITS WAY INTO THE TENNESSEE VALLEY LATE IN THE AFTERNOON AND EVENING.  
DEPENDING ON THE AMOUNT OF INSTABILITY AVAILABLE, SCATTERED TO  
NUMEROUS THUNDERSTORMS WILL BE POSSIBLE LATE IN THE DAY, WITH A  
STRONG STORM OR TWO NOT OUT OF THE QUESTION.  
 
THE INTENSITY OF WEDNESDAY'S CONVECTION WILL WANE AFTER MIDNIGHT, BUT  
EXPECT WIDESPREAD SHOWERS AND A FEW STORMS TO LINGER THROUGH THE  
OVERNIGHT HOURS, WITH LOCALLY HEAVY RAINFALL BEING THE MAIN THREAT.  
THE UPPER LOW WILL WEAKEN AS IT SHIFTS EAST INTO THE TENNESSEE VALLEY  
ON THURSDAY AND BECOMES MORE OF AN OPEN WAVE. THIS WILL PROVIDE SOME  
SLIGHTLY BETTER LIFT ACROSS THE REGION, AND POSSIBLY INCREASE THE  
LIKELIHOOD FOR A FEW STRONG TO MARGINALLY SEVERE STORMS IN THE  
AFTERNOON AND EVENING -- WITH GUSTY WINDS AND LOCALLY HEAVY DOWNPOURS  
BEING THE MAIN THREATS. OTHERWISE, EXPECT ANOTHER DAY WITH  
TEMPERATURES SLIGHTLY BELOW NORMAL, WITH HIGHS IN THE LOWER 80S  
THANKS TO THE CLOUD COVER AND ABUNDANCE OF AFTERNOON CONVECTION.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH MONDAY)  
ISSUED AT 245 PM CDT TUE MAY 26 2020  
 
BY FRIDAY, THE CLOSED UPPER LOW TRANSITIONS MORE INTO AN OPEN WAVE AS  
THE TROUGH AXIS SWINGS OVER THE SOUTHEAST, AND WILL PROVIDE ENOUGH  
SYNOPTIC FORCING TO KEEP SHOWERS AND THUNDERSTORMS IN THE FORECAST.  
MODELS APPEAR TO BE IN BETTER AGREEMENT REGARDING THIS EVOLUTION,  
ENDING ANY WIDESPREAD THUNDERSTORM ACTIVITY ACROSS THE AREA OVERNIGHT  
FRIDAY. A COLD FRONT WILL TRACK SOUTHEAST THROUGH THE VALLEY EARLY  
SATURDAY MORNING, BRINGING A DRIER AIRMASS THROUGH MUCH OF THE  
EASTERN US. ON SATURDAY, CLOUDS WILL BEGIN TO THIN AND WE WILL  
MAINTAIN ONLY A SLIGHT CHANCE FOR RAIN/THUNDERSTORMS DURING THE  
AFTERNOON HOURS. DESPITE THINNING CLOUD COVER, HIGH TEMPERATURES WILL  
ONLY REACH THE LOW 80S BEHIND THE COLD FRONT, AND LOWS WILL DIP BACK  
DOWN INTO THE 50S FOR THE FIRST TIME IN SEVERAL DAYS.  
 
EXPECT A MUCH LESS ACTIVE PATTERN THROUGH THE REMAINDER OF THE  
EXTENDED PERIOD, AS AN H5 RIDGE BUILDS INTO THE ARKLATEX AND  
EVENTUALLY SOUTHEASTERN REGION. HIGH PRESSURE WILL DIG SOUTH FROM THE  
NORTHERN PLAINS OVER THE WEEKEND, CENTERING OVER THE GREAT LAKES/OHIO  
VALLEY REGIONS EARLY NEXT WEEK. EXPECT DRY WEATHER AND TEMPERATURES  
CLOSE TO SEASONAL NORMS, WITH HIGHS IN THE LOW TO MID 80S AND  
OVERNIGHT LOWS IN THE UPPER 50S/LOW 60S.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)  
ISSUED AT 728 PM CDT TUE MAY 26 2020  
 
A FAIRLY MOIST WEATHER PATTERN WILL CONTINUE ACROSS THE REGION THRU  
THE VALID TAF PERIOD, DUE TO A DEEP LAYER OF MODERATELY STRONG  
SOUTHERLY FLOW BETWEEN A RIDGE TO OUR EAST AND A CUTOFF UPPER LOW  
OVER THE SOUTHERN PLAINS. PERIODS OF -SHRA WILL PERSIST IN THIS  
REGIME, AND ALTHOUGH IT WILL NOT RAIN THE ENTIRE TIME, WE FELT  
CONFIDENT ENOUGH TO INCLUDE LGT SHOWERS AS THE PREVAILING CONDITION  
THRU AT LEAST LATE WED MORNING. GIVEN THE VERY MOIST NATURE OF THE  
TROPICAL AIRMASS SPREADING NORTHWARD INTO THE TN VALLEY, A LOW  
STRATUS DECK IS EXPECTED TO BECOME ESTABLISHED THIS EVENING, WITH AN  
EXTENDED PERIOD OF IFR CIGS AND MINOR VSBY REDUCTIONS TO 5SM  
ANTICIPATED BTWN 06-16Z. THE STRATUS LAYER WILL BEGIN TO LIFT/SCATTER  
BY EARLY WED AFTN, ALLOWING FOR GREATER DESTABILIZATION AND THE  
DEVELOPMENT OF TSRA, WHICH MAY IMPACT THE TERMINALS BTWN 19-24Z. SFC  
FLOW WILL REMAIN FROM THE SE AT 5-10 KNOTS OVERNIGHT, BUT SHOULD  
SLIGHTLY VEER/WEAKEN DURING THE SECOND HALF OF THE TAF PERIOD.  
 

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

 
 

 
 
NEAR TERM...AMP.24  
SHORT TERM...AMP.24  
LONG TERM...25  
AVIATION...70/DD  
 
FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE  
AT WEATHER.GOV/HUNTSVILLE.  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab AL Page
The Nexlab TN Page Main Text Page