866  
FXUS64 KBMX 020017  
AFDBMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BIRMINGHAM AL  
717 PM CDT SUN AUG 1 2021  
   
UPDATE
 
 
FOR 00Z AVIATION.  
 

 
   
SHORT TERM
 
 
/UPDATED AT 1258 PM CDT SUN AUG 01 2021/  
TODAY THROUGH MONDAY.  
 
FEATURES OF INTEREST.  
 
A DEEP-LAYER TROUGH EXTENDED FROM SOUTHEAST CANADA THROUGH THE  
OHIO RIVER VALLEY AND DIPPED INTO THE TENNESSEE VALLEY REGION THIS  
MORNING WITH SUBTLE TROUGHING OVER THE TENNESSEE VALLEY THIS  
MORNING WHILE ANOTHER IMPULSE IN THE FLOW WAS ANALYZED ACROSS  
PORTIONS OF IOWA AND KANSAS. THE MIDDLE AND LOWER LEVELS ARE  
CHARACTERIZED BY PERSISTENT RIDGING LOCATED NEAR BERMUDA WHILE A  
LESSER EXTENT OF RIDGING WAS ANALYZED TO OUR SOUTHWEST, WHICH  
EXTENDED NORTHWEST INTO THE HIGH PLAINS.  
 
TOWARD THE SURFACE, DEW POINT VALUES REMAIN THE HIGHEST ACROSS  
THE WESTERN HALF OF THE AREA WITH DEW POINTS IN THE MID TO UPPER  
79S WITH VALUES IN THE LOWER 70S ELSEWHERE. WEAK SURFACE PRESSURE  
TROUGHING WAS ANALYZED FROM NORTH CAROLINA THAT EXTENDED SOUTHWEST  
ACROSS CENTRAL GEORGIA INTO OUR SOUTHERN COUNTIES. OVERALL, A  
COLD FRONT EXTENDED FROM NORTHERN TEXAS THAT STRETCHED EAST ACROSS  
THE MID SOUTH REGION AND INTO SOUTHEAST TENNESSEE. A WEAK LOW WAS  
ANALYZED NEAR TUPELO, MS. SURFACE HIGH PRESSURE WAS POSITIONED  
OFF THE SOUTHEASTERN U.S. COASTLINE OVER THE SOUTHWEST ATLANTIC  
BASIN.  
 
HAZARD ASSESSMENT.  
 
OBSERVED 01/12Z BMX SOUNDING ALONG WITH MODEL FORECAST SOUNDINGS  
ARE IN A GOOD AGREEMENT FOR AN UPPER-END MODERATE WET MICROBURST  
RISK TODAY. A TROPICAL AIRMASS NEAR THE SURFACE IS POSITIONED  
BENEATH A SLUG OF DRIER AIR ALOFT. THIS CONFIGURATION WILL SUPPORT  
THE RISK FOR LOCALIZED DAMAGING MICROBURST WINDS FROM THE HEAVIER  
CONVECTION TODAY.  
 
A WEAK COLD FRONT EXTENDED FROM WEST TO EAST JUST NORTH OF THE  
FORECAST AREA. RARE FOR SUMMERTIME GENERALLY, THE ENVIRONMENT IS  
LIGHTLY TO MODERATELY SHEARED, WHICH WILL PROMOTE STORM  
ORGANIZATION. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE WITH  
THE HEAVIER ACTIVITY THAT DEVELOPS TODAY. DAMAGING WINDS WILL BE  
THE PRIMARY CONCERN, CONTRIBUTED BY THE WET MICROBURST RISK  
MENTIONED ABOVE.  
 
ADDITIONALLY, WAVES OF SHOWERS AND STORMS MOVING OVER THE SAME  
AREAS WILL POSE A RISK FOR LOCALIZED FLOODING DUE TO THE  
TORRENTIAL DOWNPOURS WITH RAIN RATES IN EXCESS OF ONE INCH AN HOUR  
EXPECTED.  
 
NEAR TERM.  
 
WITH SEVERAL OUTFLOW BOUNDARIES ACROSS THE AREA, UNCERTAINTY IS  
HIGHER THAN TYPICAL, HOWEVER, THE MOST "EFFECTIVE" BOUNDARY  
APPEARS TO BE THE ONE EXTENDING FROM NEAR TUSCALOOSA EAST TO NEAR  
SYLACAUGA. EXPECT BEST CHANCES ALONG AND SOUTH OF THIS BOUNDARY  
THROUGH MID AFTERNOON, FOLLOWED BY SOME INCREASED CONVECTIVE  
POTENTIAL ACROSS THE AREAS NORTH OF THIS BOUNDARY. SCATTERED  
SHOWERS AND STORMS LOOK TO LINGER PAST SUNSET TONIGHT INTO THE  
EVENING HOURS, FOLLOWED BY THE POTENTIAL FOR SOME LINGERING  
SHOWERS AND PERHAPS A THUNDERSTORM OR TWO OVERNIGHT.  
 
TODAY.  
 
SEVERAL BOUNDARIES WILL MOVE ACROSS THE AREA AS A WEAK COLD FRONT  
APPROACHES FROM THE NORTHWEST TODAY.  
 
EXPECT PARTLY CLOUDY SKIES WITH SCATTERED TO NUMEROUS SHOWERS AND  
THUNDERSTORMS TODAY. SOME STORMS MAY PRODUCE STRONG WINDS. HIGHS  
TODAY WILL RANGE FROM THE MID 80S NORTH TO THE MID 90S SOUTH  
ALONG AND SOUTH OF THE U.S. HIGHWAY 80 CORRIDOR. WINDS WILL BECOME  
NORTHWEST 5-10 MPH.  
 
TONIGHT.  
 
EXPECT THE WEAK FRONT TO MOVE INTO OUR NORTHERN COUNTIES TONIGHT,  
HELPING TO REDUCE DEW POINTS A FEW DEGREES ACROSS THE FAR NORTH.  
BETTER CHANCES FOR SHOWERS AND STORMS WILL BE ACROSS THE SOUTHERN  
PORTION OF THE AREA AS A DISTURBANCE MOVES EAST ALONG THE FRONT.  
 
LOOK FOR A GRADUAL DECREASE IN SHOWERS AND THUNDERSTORMS TONIGHT  
WITH THE BETTER CHANCES ACROSS THE SOUTHERN HALF OF THE FORECAST  
AREA. WINDS WILL BE LIGHT OVERNIGHT WITH LOWS RANGING FROM THE  
UPPER 60S FAR NORTH/NORTHEAST TO READINGS IN THE MID 70S  
SOUTH/SOUTHWEST.  
 
MONDAY.  
 
A WEAK COLD FRONT WILL REMAIN ACROSS OUR CENTRAL COUNTIES ON  
MONDAY AND WILL RESULT IN A SLIGHTLY LESS HUMID ENVIRONMENT WITH  
LOWER POPS NORTH, WHILE MORE HUMID CONDITIONS WITH HIGHER CHANCES  
FOR SHOWERS AND STORMS WILL EXIST ACROSS THE SOUTHERN PORTION OF  
THE FORECAST AREA.  
 
PARTLY CLOUDY SKIES ARE FORECAST MONDAY WITH SCATTERED SHOWERS AND  
THUNDERSTORMS DEVELOPING. THE BEST CHANCES WILL BE ACROSS THE  
SOUTHERN HALF OF THE FORECAST AREA. HIGHS WILL RANGE FROM THE  
LOWER 80S FAR NORTH TO AROUND 90 SOUTHEAST. WINDS WILL BE OUT OF  
THE NORTHWEST 5-10 MPH.  
 
05  
   
LONG TERM
 
 
/UPDATED AT 305 PM CDT SUN AUG 01 2021/  
 
HIGHLY AMPLIFIED TROUGH OVER THE EASTERN CONUS DISPLAYS SOME  
HEIGHT FALLS TUESDAY NIGHT. THE UPPER RIDGE IN THE WESTERN  
ATLANTIC BEGINS BUILDING SOUTHWESTWARD WEDNESDAY AND THURSDAY.  
SIMULTANEOUSLY, THE UPPER LOW WAY UP IN NEAR HUDSON BAY EJECTS  
NORTHEASTWARD AND THIS WILL LEAD TO A WEAKENING OF THE TROUGH OVER  
THE EASTERN CONUS. THIS APPEARS SHORT-LIVED AS ANOTHER UPPER  
TROUGH BEGINS DEVELOPING BUT DOES NOT LOOK TO BE A SEMI-PERMANENT  
FEATURE. A SMALL CHANGE WAS MADE TO POPS MONDAY NIGHT INTO TUESDAY  
NIGHT WITH A TAD SLOWER EXIT TREND OF POPS. OTHERWISE, THE  
FORECAST TREND LOOKS GOOD WITH ONLY SMALL ADJUSTMENTS OF  
TEMPERATURES HERE AND THERE. THE LOSS OF OPPRESSIVE HEAT IS MAIN  
STORY.  
 
75  
 
PREVIOUS LONG-TERM DISCUSSION:  
/UPDATED AT 257 AM CDT SUN AUG 01 2021/  
MONDAY NIGHT THROUGH SATURDAY.  
 
AN AMPLIFIED LONGWAVE TROUGH WILL REMAIN OVER THE EASTERN CONUS  
THROUGH WEDNESDAY. IT WILL BE REINFORCED BY SEVERAL SHORTWAVES  
ROTATING AROUND THE BASE OF THE TROUGH. THE EFFECTIVE COLD FRONT  
SHOULD BE SOUTH OF THE AREA BY MONDAY EVENING, ALONG WITH THE  
MORE ROBUST CONVECTION. HOWEVER, MODELS DISAGREE ON THE AMOUNT OF  
POST-FRONTAL LIFT FOR SHOWERS/ISOLATED THUNDERSTORMS MONDAY NIGHT  
ACROSS THE AREA. THE FRONT WILL REMAIN STALLED NEAR OR SOUTHEAST  
OF OUR SOUTHEAST COUNTIES THROUGH MUCH OF THE WEEK. DRIER AIR WILL  
BE FILTERING INTO THE AREA, BUT WITH PLENTIFUL MOISTURE JUST  
SOUTHEAST OF THE AREA, SHORTWAVES ROTATING THROUGH THE TROUGH MAY  
INDUCE WAVES OF LOW PRESSURE ALONG THE FRONT WHICH COULD ENHANCE  
MOISTURE FROM THE EAST AT TIMES. DETERMINISTIC MODELS/ENSEMBLE  
MEMBERS SHOW DISAGREEMENT ON RAIN CHANCES THROUGH MUCH OF THE  
WEEK, SO KEPT CLOSE TO THE PREVIOUS FORECAST WITH HIGHEST CHANCES  
SOUTHEAST AND VERY LIMITED CHANCES NORTHWEST. WE WILL SEE A  
WELCOME RELIEF FROM THE RECENT HIGH DEWPOINTS/HEAT INDICES, AND  
ALSO SEE COOLER LOW TEMPERATURES IN THE 60S AS WELL. THE TROUGH  
WEAKENS BY THURSDAY, BUT OVERALL CYCLONIC FLOW REMAINS WITH  
ANOTHER SHORTWAVE TROUGH MOVING THROUGH ON FRIDAY. TEMPERATURES  
WILL BEGIN TO WARM BACK UP AS THE FRONT BECOMES MORE DIFFUSE, BUT  
THE DEEP LAYER MOISTURE GRADIENT WILL REMAIN THROUGH THE END OF  
THE PERIOD WITH CONTINUED ENSEMBLE SPREAD REGARDING ITS EXACT  
POSITION.  
 
32/DAVIS  
 

 
   
AVIATION
 
 
00Z TAF DISCUSSION.  
 
FRONTAL BOUNDARY MOVING S ACROSS C AL THIS EVENING CURRENTLY  
BETWEEN I22 AND I20/59 W OF BHM AND JUST S OF I20 E OF BHM. TSRA  
WILL BE POSSIBLE ALONG AND S OF THE BOUNDARY AS IT SAGS SWD THRU  
THE TAF PERIOD. SOME MVFR CONDITIONS ALONG WITH A FEW GUSTS AT  
TIMES WILL BE POSSIBLE WITH THE STORMS.  
 
08  
 

 
   
FIRE WEATHER
 
 
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP  
OVER CENTRAL ALABAMA EACH AFTERNOON THROUGH MONDAY. A DECREASE IN  
RAIN CHANCES CAN BE EXPECTED TUESDAY THROUGH FRIDAY, BUT STILL  
SCATTERED IN NATURE. LOW LEVEL MOISTURE REMAINS VERY HIGH THROUGH  
MONDAY WITH MINIMUM RH VALUES OVER 50 PERCENT. SOME DROP IS  
EXPECTED THE REMAINDER OF THE WEEK BUT ONLY INTO THE 40S. AS IS  
TYPICAL OF THE SUMMER PATTERN, TRANSPORT WINDS REMAIN RATHER  
LIGHT.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GADSDEN 68 85 65 87 65 / 20 20 20 20 10  
ANNISTON 69 86 67 87 66 / 30 20 30 30 10  
BIRMINGHAM 71 87 68 87 67 / 30 20 20 20 10  
TUSCALOOSA 73 87 68 87 67 / 40 40 30 10 10  
CALERA 71 86 68 86 67 / 40 30 30 20 10  
AUBURN 72 87 69 85 69 / 50 70 40 50 20  
MONTGOMERY 73 88 70 87 69 / 50 90 50 40 20  
TROY 73 89 70 87 70 / 50 90 70 60 30  
 

 
   
BMX WATCHES/WARNINGS/ADVISORIES/
 
 
HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING  
COUNTIES: AUTAUGA...BARBOUR...BIBB...BULLOCK...CHAMBERS...  
CHILTON...CLAY...COOSA...DALLAS...ELMORE...FAYETTE...GREENE...  
HALE...JEFFERSON...LAMAR...LEE...LOWNDES...MACON...MARENGO...  
MONTGOMERY...PERRY...PICKENS...PIKE...RANDOLPH...RUSSELL...  
SHELBY...ST. CLAIR...SUMTER...TALLADEGA...TALLAPOOSA...  
TUSCALOOSA...WALKER.  
 

 
 

 
 
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