123  
FXUS64 KBMX 180018  
AFDBMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BIRMINGHAM AL  
718 PM CDT THU AUG 17 2017  
   
UPDATE
 
 
FOR 00Z AVIATION.  
 

 
   
SHORT TERM
 
 
REST OF THIS AFTERNOON THROUGH FRIDAY.  
 
--VARIED CLOUDINESS W/ CHANCES FOR PERIODIC SHOWERS AND STORMS  
TODAY THROUGH FRIDAY AS A FRONT NUDGES INTO THE REGION--  
 
500MB RIDGING CENTERED ALONG THE NORTH-CENTRAL GULF COAST REMAINS  
IN CONTROL AT MIDDAY, BUT EXPECTATIONS ARE FOR SOME LOSS OF  
DOMINANCE LATER TODAY AND FRIDAY AS SEVERAL SMALL UPPER-LEVEL  
IMPULSES SKIRT ALONG THE SOUTHERN PERIMETER OF A LARGER-SCALE  
TROUGH AND EMBEDDED SHORTWAVES ATOP THE GREAT LAKES REGION. A  
SURFACE FRONT WILL ALSO BE MAKING ITS WAY INTO CENTRAL ALABAMA  
DURING THE PERIOD.  
 
AS OF 17:35/12:35PM, GOES-16 VISIBLE SATELLITE SHOWED SCATTERED  
CUMULUS ACROSS THE REGION AND RADAR SHOWED A FEW LIGHT RETURNS AS  
WE APPROACH THE CONVECTIVE TEMP. FOR THE DAY. SPOTTY  
SHOWERS/STORMS ARE EXPECTED AS WE STEP THROUGH THE AFTERNOON WITH  
OVERALL LIMITED COVERAGE GIVEN INFLUENCE FROM THE RIDGE; HOWEVER,  
TRENDS STILL FAVOR 'BETTER' CHANCES ACROSS THE NORTHWESTERN  
PORTIONS OF THE FORECAST AREA LATE AFTERNOON INTO EVENING AS THE  
FIRST UPPER IMPULSE ARRIVES. WITH SIMILAR FEATURES IN TOW  
OVERNIGHT AND FRIDAY + ARRIVAL AND PROGRESSION OF THE SURFACE  
FRONT, SPOTS OF SHOWERS/STORM (PROBABLY FAIRLY ISOLATED) COULD  
DEVELOP OVERNIGHT INTO FRIDAY MORNING ANYWHERE ACROSS CENTRAL  
ALABAMA. DAYTIME HEATING WILL SPARK BUDDING SHOWERS AND STORMS  
THROUGH FRIDAY AS THE MAIN PRECIP. AXIS SHIFTS SOUTHEASTWARD.  
 
HEAT INDICES WILL EDGE TOWARD 105F THROUGH THE SOUTHERN-THIRD, OR  
SO, OF CENTRAL ALABAMA THIS AFTERNOON.  
 
89^GSATTERWHITE  
   
LONG TERM
 
 
FRIDAY THROUGH THURSDAY.  
 
THE COLD FRONT IS SOUTH OF OUR AREA BY SATURDAY MORNING AS AN  
UPPER LOW RETROGRADES THROUGH THE GULF OF MEXICO. WILL KEEP RAIN  
CHANCES FOR THE NORTHERN HALF OF CENTRAL AL LOW ON SATURDAY, WITH  
30-40% STILL POSSIBLE IN THE SOUTHERNMOST COUNTIES DUE TO  
PROXIMITY OF THE NOW STATIONARY COLD FRONT IN SOUTHERN AL. ON  
SUNDAY, THE FRONTAL BOUNDARY IS LIFTED SLIGHTLY NORTHWARDS, BUT  
REMAINS FAIRLY WEAK. HAVE THEREFORE KEPT CHANCE POPS GENERALLY  
SOUTH OF THE I-20 CORRIDOR WITH SLIGHT CHANCE IN THE NORTH. COULD  
ARGUE FOR EVEN LOWER POPS IN THE NORTHERNMOST COUNTIES, BUT WILL  
KEEP THEM AROUND 15% FOR NOW.  
 
UPPER-LEVEL RIDGING BUILDS IN MONDAY AND TUESDAY. THE GFS WANTS TO  
KEEP THE AREA DRIER, WHILE THE ECMWF DEVELOPS THE TYPICAL SUMMERTIME  
AIRMASS THUNDERSTORMS IN THE AFTERNOONS. HAVE LEANED TOWARDS THE EC  
AND CLIMATOLOGY HERE AND GONE WITH 30-40% POPS AREA-WIDE SIMPLY  
BASED ON THE SYNOPTIC PATTERN AND THE MOIST BOUNDARY LAYER. THE  
PATTERN CHANGES AS WE REACH THE MIDDLE PART OF NEXT WEEK AS  
TROUGHING BUILDS INTO THE EASTERN US. MODELS HINT AT ANOTHER COLD  
FRONT PUSHING SOUTHWARD, WHICH WOULD INCREASE RAIN CHANCES ACROSS  
CENTRAL AL ON WEDNESDAY AND THURSDAY.  
 
25/OWEN  
 

 
   
AVIATION
 
 
00Z TAF DISCUSSION.  
 
CONVECTIVE ACTIVITY FALLING APART AS IT MOVES INTO ALABAMA. NOT  
MUCH IS EXPECTED DURING THE OVERNIGHT HOURS. SOME MVFR AND  
POSSIBLY IN A FEW SPOTS IFR CLOUDS ARE POSSIBLE FOR THE LATE  
NIGHT INTO EARLY MORNING HOURS ONCE AGAIN. WHILE SOME MVFR FOG IS  
NOT TO BE RULED OUT, THINK THE MAIN STORY WILL BE LOW CIGS.  
ANOTHER SIMILAR DAY IS ON TAP FOR FRIDAY. THE WINDS WILL BECOMING  
A LITTLE MORE WNW IN THE DAY AS A FRONT DIPS SOUTHWARD TEMPORARILY  
INTO N AL. SOME SCATTERED CONVECTION IS NOT TO BE RULED OUT FOR  
FRIDAY AFTERNOON AHEAD OF BOUNDARY, BUT WILL HOLD OFF PUTTING IN  
TAF JUST YET.  
 
08  
 

 
   
FIRE WEATHER
 
 
 
SCATTERED RAIN CHANCES POSSIBLE TODAY, INCREASING SLIGHTLY FOR  
FRIDAY. THERE ARE NO FIRE WEATHER CONCERNS AT THIS TIME DUE TO  
THE ABUNDANT MOISTURE.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GADSDEN 73 89 70 91 71 / 30 30 10 10 10  
ANNISTON 74 90 72 91 72 / 30 40 10 10 10  
BIRMINGHAM 76 91 73 92 74 / 40 40 10 10 10  
TUSCALOOSA 75 93 74 94 73 / 40 40 10 20 10  
CALERA 75 91 73 92 73 / 30 40 10 20 10  
AUBURN 75 90 74 90 73 / 10 40 20 20 20  
MONTGOMERY 76 93 76 93 75 / 10 40 20 30 20  
TROY 74 93 74 92 74 / 10 50 30 40 20  
 

 
   
BMX WATCHES/WARNINGS/ADVISORIES/
 
 
NONE.  
 

 
 

 
 
89/25/08  
 
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