626
FXUS64 KBMX 201128
AFDBMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
628 AM CDT THU AUG 20 2026
..NEW AVIATION
KEY MESSAGES
ISSUED AT 613 AM CDT THU AUG 20 2026
- HEAT: MAJOR HEATRISK IS EXPECTED TO PERSIST THROUGH THE END OF
THE WORKWEEK, WITH HEAT INDICES ARE FORECAST BETWEEN 103 TO 108
DEGREES. A HEAT ADVISORY IS IN EFFECT FOR PORTIONS OF CENTRAL
ALABAMA THROUGH THURSDAY AND MAY BE NEEDED FOR FRIDAY.
- THUNDERSTORMS: ISOLATED TO SCATTERED AFTERNOON TO EVENING
THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH SATURDAY. RAIN
CHANCES WILL INCREASE THIS WEEKEND.
- SEVERE: ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND EARLY EVENING WITH DAMAGING WIND THE MAIN THREAT.
DISCUSSION
(THURSDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 1157 PM CDT WED AUG 19 2026
A LOW PRESSURE OVER THE GREAT LAKES SHIFTS NORTHEAST, DRAGGING A
COLD FRONT SOUTHWARD THROUGH THE TN VALLEY AND INTO NORTHERN
ALABAMA BY THE AFTERNOON. ENOUGH INSTABILITY WILL SUPPORT
SCATTERED SHOWERS AND THUNDERSTORMS LATE AFTERNOON THROUGH AT
LEAST MIDNIGHT, TAPERING OFF OVERNIGHT. WHILE THERMODYNAMIC
PARAMETERS REMAIN SIMILAR, GREATER BOUNDARY CONVERGENCE SHOULD
RESULT IN HIGHER CONVECTIVE COVERAGE. HIGH CAPE, DRY MID-LEVEL
AIR, AND FAIRLY HIGH DCAPE SUGGEST DAMAGING DOWNBURSTS REMAIN THE
PRIMARY THREAT WITH COLLAPSING STORMS. THE HEAT ADVISORY
CONTINUES THROUGH 9 PM AND WILL LIKELY NEED TO BE EXTENDED AGAIN
THROUGH FRIDAY AS HIGH MOISTURE AND LOWS IN THE 70S PROVIDE
LITTLE RELIEF.
BY FRIDAY, AN AMPLIFYING TROUGH EAST OF THE MS RIVER WILL SHIFT
LOCAL FLOW TO THE NORTHWEST AND EVENTUALLY WEST. THE
AFOREMENTIONED BOUNDARY WILL CONTINUE ITS SOUTHWARD PUSH,
FOCUSING DIURNAL CONVECTION GENERALLY BETWEEN THE I-20 AND I-
85 CORRIDORS. A CONTINUED RISK FOR DOWNBURST WINDS EXISTS GIVEN
THE PERSISTENT AIRMASS. TEMPERATURES MAY TREND A FEW DEGREES
LOWER, BUT HIGH HUMIDITY WILL MAINTAIN HEAT INDICES IN THE TRIPLE
DIGITS.
MODEL UNCERTAINTY PERSISTS REGARDING THE SOUTHERN PROGRESS OF THE
BOUNDARY ON SATURDAY. WHILE SOME GUIDANCE SUGGESTS WIDESPREAD
CONVECTION, RECENT RUNS FAVOR THE TROUGH AXIS MOVING THROUGH WITH
PREVAILING NORTHWEST FLOW. A WEAK MID-LEVEL JET COULD INCREASE
SURFACE WINDS ACROSS THE NORTH, WITH GUSTS OF 20-25 MPH POSSIBLE.
RAIN CHANCES REMAIN IN THE FORECAST PENDING BETTER MODEL
CONSISTENCY. NORTHWEST FLOW AND MODEST COLD AIR ADVECTION WILL
DROP TEMPERATURES FOR THE WEEKEND; HEAT INDICES SHOULD FINALLY
FALL BELOW 105 DEGREES, THOUGH THEY WILL REMAIN IN THE 100-
104 RANGE.
BRIEF HIGH PRESSURE GIVES WAY TO ANOTHER DEVELOPING LOW MOVING
ACROSS THE TENNESSEE VALLEY REGION TOWARD THE END OF THE PERIOD,
BRINGING AN INCREASE IN RAIN CHANCES. TIMING DIFFERENCES
REGARDING THE TROUGH EXIT AND LOW PROGRESSION REMAIN; WILL ADJUST
THE FORECAST AS TRENDS EMERGE.
16
AVIATION
(12Z TAFS)
ISSUED AT 613 AM CDT THU AUG 20 2026
VFR CONDITIONS WILL PREVAIL ACROSS MUCH OF THE AREA THROUGH
MIDDAY, FOLLOWED BY CUMULUS DEVELOPMENT BECOMING WIDESPREAD WITH
CHANCES FOR SHOWERS AND THUNDERSTORMS HIGH ENOUGH TO INCLUDE
PROB30 AT ALL SITES FROM THE MID AFTERNOON INTO THE EVENING HOURS.
SOME OUTFLOW BOUNDARIES FROM OVERNIGHT ACTIVITY TO OUR NORTH HAS
MOVED SOUTH INTO NORTHERN ALABAMA EARLY THIS MORNING AND IS
TRIGGERING SOME SHOWERS AND STORMS ACROSS THE FAR NORTHERN
PORTIONS OF THE STATE. WHILE LOW PROBABILITY, A FEW SHOWERS OR
STORMS MAY DEVELOP EARLIER THAN FORECAST, BUT POTENTIAL FOR THIS
OUTCOME IS TOO LOW TO MENTION AT ANY TERMINAL AT THIS TIME.
NOTE: AMD NOT SKED FOR AUO DUE TO A WEATHER OBSERVATION OUTAGE.
05
05
FIRE WEATHER
MINRH VALUES WILL GENERALLY RANGE BETWEEN 35 AND 45% THE NEXT FEW
DAYS, BEFORE SLOWLY CLIMBING INTO THE WEEKEND AHEAD OF INCREASING
RAIN CHANCES. WINDS WILL REMAIN LIGHT THE NEXT FEW DAYS, BEFORE
INCREASING INTO THE WEEKEND AS WELL. FIRE WEATHER CONCERNS ARE
CURRENTLY LOW, BUT THEY WILL START TO INCREASE BY MONDAY NO
MEANINGFUL RAINFALL OCCURS WITH THIS WEEKEND'S SYSTEM.
PRELIMINARY POINT TEMPS/POPS
GADSDEN 98 72 94 70 / 30 50 30 10
ANNISTON 96 72 92 70 / 30 50 50 20
BIRMINGHAM 97 73 92 71 / 30 50 40 10
TUSCALOOSA 100 74 96 72 / 30 40 30 10
CALERA 96 73 93 71 / 30 50 50 20
AUBURN 94 74 91 73 / 20 40 60 30
MONTGOMERY 98 74 96 73 / 30 40 60 30
TROY 97 72 94 71 / 30 40 70 30
BMX WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
COUNTIES: AUTAUGA-BARBOUR-BIBB-BULLOCK-CHILTON-COOSA-DALLAS-
ELMORE-FAYETTE-GREENE-HALE-JEFFERSON-LAMAR-LOWNDES-MACON-MARENGO-
MARION-MONTGOMERY-PERRY-PICKENS-PIKE-SHELBY-SUMTER-TUSCALOOSA-
WALKER.
DISCUSSION...16
AVIATION...05
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