820  
FXUS64 KBMX 232319  
AFDBMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BIRMINGHAM AL  
619 PM CDT SAT OCT 23 2021  
   
UPDATE
 
 
FOR 00Z AVIATION.  
 

 
   
SHORT TERM
 
 
/UPDATED AT 1230 PM CDT SAT OCT 23 2021/  
 
TODAY THROUGH SUNDAY.  
 
FEATURES OF INTEREST.  
 
ZONAL FLOW ALOFT IS THE PATTERN OVER MUCH OF THE SOUTHEAST TODAY  
AS AN EXPANSIVE UPPER LOW REMAINS POSITIONED NEAR THE SOUTHERN  
PORTION OF HUDSON BAY IN CANADA. A LONGWAVE RIDGE EXTENDED FROM  
CENTRAL TEXAS NORTH TO OVER SOUTH DAKOTA WHILE A TROUGH STRETCHED  
FROM WESTERN MONTANA SOUTHWEST INTO COLORADO.  
 
TOWARD THE SURFACE, HIGH PRESSURE WAS CENTERED NEAR KNOXVILLE, TN  
WHILE A STATIONARY FRONT EXTENDED FROM NEAR NEW ORLEANS EAST TO  
NEAR ORLANDO AND TO THE NORTHEAST JUST OFF THE SOUTHEAST U.S.  
COASTLINE.  
 
TODAY.  
 
MID-LEVEL RIDGING WILL MOVE EAST, EXTENDING FROM OVER THE OZARKS  
NORTH TO OVER SOUTH DAKOTA LATER TODAY. SURFACE HIGH PRESSURE WILL  
CONTINUE TO MOVE FURTHER NORTHEAST OF THE AREA, BECOMING CENTERED  
OVER CENTRAL NORTH CAROLINA LATER THIS AFTERNOON. A WARM FRONT  
WILL BECOME BETTER DEFINED AS IT MOVES NORTHEAST ACROSS THE  
ARKLATEX REGION TO OUR WEST.  
 
EXPECT MOSTLY SUNNY SKIES TODAY WITH ONLY A FEW HIGH CLOUDS  
NORTH. HIGHS WILL RANGE FROM THE MID 70S NORTHEAST TO READINGS IN  
THE LOW 80S SOUTHWEST. WINDS WILL BECOME SOUTHEAST LATER THIS  
AFTERNOON FROM 5-10 MPH.  
 
TONIGHT.  
 
BROAD MID-LEVEL RIDGING WILL MOVE FURTHER EAST FROM THE PLAINS,  
EXTENDING FROM THE MID SOUTH REGION NORTHWEST TO OVER MINNESOTA  
OVERNIGHT. TROUGHING WILL DIG FURTHER SOUTHEAST FROM MONTANA  
SOUTHEAST INTO NEW MEXICO. MOST MODELING ALSO INDICATES FALLING  
HEIGHTS ALONG THE TEXAS AND LOUISIANA COAST THIS EVENING INTO THE  
OVERNIGHT AS A DISTURBANCE FURTHER DEVELOPS ALOFT.  
 
LOOK FOR MOSTLY CLEAR SKIES OVERNIGHT WITH A FEW HIGH CLOUDS  
SOUTHWEST. SOME PATCHY FOG MAY AGAIN DEVELOP AT AND NEAR WATER  
BODIES BEFORE SUNRISE ON SUNDAY MORNING. LOWS WILL RANGE FROM THE  
MID 40S NORTHEAST TO THE MID 50S WEST. WINDS WILL BE LIGHT FROM  
THE SOUTH 3-6 MPH.  
 
SUNDAY.  
 
MID-LEVEL RIDGING WILL EXTEND FROM GEORGIA NORTHWEST TO OVER  
MISSOURI WHILE TROUGHING AMPLIFIES FROM NEBRASKA SOUTHEAST INTO  
LOUISIANA. A WEAK DISTURBANCE LOOKS TO BE POSITIONED OVER THE  
SOUTHERN MISSISSIPPI RIVER VALLEY. SURFACE HIGH PRESSURE WILL MOVE  
FURTHER NORTHEAST, BECOMING CENTERED ACROSS THE MID ATLANTIC  
REGION WHILE LOWER SURFACE PRESSURES WILL BE FOUND ACROSS THE  
CENTRAL AND SOUTHERN PLAINS.  
 
SKIES WILL BECOME PARTLY CLOUDY ACROSS THE FAR WEST AND SOUTHWEST  
DURING THE DAY SUNDAY BUT DRY CONDITIONS ARE EXPECTED TO PERSIST.  
HIGHS WILL RANGE FROM THE UPPER 70S IN THE EASTERN HIGHLANDS TO  
READINGS IN THE LOWER 80S SOUTH AND WEST. WINDS WILL INCREASE FROM  
THE SOUTHEAST FROM 5-10 MPH ACROSS THE EAST AND FROM 6-12 MPH  
ACROSS THE WESTERN HALF OF THE FORECAST AREA.  
 
05  
   
LONG TERM
 
 
/UPDATED AT 0152 PM CDT SAT OCT 23 2021/  
 
TWO ACTIVE PERIODS IN THE EXTENDED: MONDAY AND WEDNESDAY THRU  
THURSDAY. MONDAY CONTINUES TO PRESENT AS A LOW END SEVERE THREAT  
AS A FRONT DRAGS THROUGH THE AREA, ATTACHED TO A SURFACE LOW  
MOVING THROUGH THE SOUTHERN GREAT LAKES. LIMITED FORCING QUICKLY  
PULLS AWAY FROM THE AREA DURING THE MORNING, BEFORE INSTABILITY  
HAS A CHANCE TO INCREASE. CANNOT RULE OUT A STRONG TO SEVERE  
STORM, BUT CONFIDENCE IS TOO LOW TO INCLUDE IN THE HWO.  
 
MODELS CONTINUE TO DISAGREE ON KEY FEATURES FOR THE MID WEEK  
SYSTEM, LIKE THE INFLUENCE OF A LEADING SHORT WAVE LATE WEDNESDAY  
AND THE NORTHWARD EXTENT OF THE WARM SECTOR. WILL NOT MAKE MANY  
CHANGES IN THIS PERIOD DUE TO THESE DIFFERENCES. HOWEVER, DID  
INCREASE WINDS AND WIND GUSTS WED THRU FRI DUE TO THE TIGHTENED  
SURFACE GRADIENT AND STRENGTHENING SURFACE LOW, GOING ON THE  
HIGHER END OF GUIDANCE.  
 
14  
 
PREVIOUS LONG-TERM DISCUSSION:  
/UPDATED AT 0343 AM CDT SAT OCT 23 2021/  
 
MONDAY THROUGH FRIDAY.  
 
A LOW PRESSURE SYSTEM IS EXPECTED TO MOVE THROUGH THE OHIO VALLEY  
LATE SUNDAY NIGHT THROUGH MONDAY AND WILL PUSH A COLD FRONT  
SOUTHEASTWARD THROUGH CENTRAL AL. THERE WILL BE ENOUGH INSTABILITY  
AHEAD OF THIS FRONT TO SUPPORT THUNDERSTORMS, BUT THE DYNAMICS OF  
THIS SYSTEM WEAKEN AS THE LOW LIFTS QUICKLY NORTHEASTWARD AND THE  
WIND PROFILES VEER IN THE LOWER LEVELS AHEAD OF THE FRONT, SO ANY  
SEVERE POTENTIAL IS LIMITED WITH THIS ACTIVITY, THOUGH A FEW  
STRONGER STORMS CAN'T BE RULED OUT COMPLETELY.  
 
RIDGING BUILDS IN ACROSS THE REGION TUESDAY INTO WEDNESDAY AS WE GET  
CAUGHT BETWEEN THE TROUGH AND ASSOCIATED LOW TO OUR EAST AND A  
SECOND TROUGH DEEPENING THROUGH THE CENTRAL PLAINS TO OUR WEST. THIS  
SECOND TROUGH IS EXPECTED TO DEVELOP A SURFACE LOW AND SLIDE THROUGH  
THE ARKLATEX SOMETIME WEDNESDAY INTO EARLY THURSDAY MORNING, LIFTING  
A WARM FRONT NORTHWARD INTO SOUTHERN PORTIONS OF CENTRAL AL.  
 
THERE'S STILL QUITE A BIT OF UNCERTAINTY WITH THE OVERALL  
EVOLUTION OF THIS TROUGH, ESPECIALLY IN TERMS OF HOW STRONG IT  
BECOMES AND THE TRACK AND TIMING OF THE SURFACE LOW. THIS IS KEY  
IN DETERMINING THE THERMODYNAMIC PROFILE, AND THEREFORE SEVERE  
WEATHER CHANCES, ACROSS CENTRAL AL. WITH THE PROXIMITY OF THE  
SURFACE LOW, WHICH IS EXPECTED TO BE DEEPENING AS IT APPROACHES  
THE REGION, COMBINED WITH THE FORECASTED NEGATIVE TILT OF THE  
UPPER TROUGH, I THINK THE KINEMATICS WOULD GENERATE MORE THAN  
ENOUGH SHEAR AND SYNOPTIC LIFT TO SUPPORT STRONG TO SEVERE STORMS.  
THE QUESTION COMES BACK TO THE PLACEMENT OF THE WARM SECTOR (I.E.  
HOW FAR NORTH DOES THE WARM FRONT GO) TO SUPPORT THE  
DESTABILIZATION OF THE ENVIRONMENT AHEAD OF THE COLD FRONT. THIS  
IS A COMMON UNCERTAINTY WITH SYSTEMS THIS TIME OF YEAR - AND ONE  
THAT MODEL GUIDANCE WILL LIKELY GO BACK AND FORTH ON OVER THE NEXT  
FEW DAYS. BASED ON CURRENT DATA, I DO THINK THERE'S SOME  
POTENTIAL FOR SEVERE STORMS IN OUR SOUTHERN COUNTIES, GENERALLY  
ALONG AND SOUTH OF THE HWY 80/I-85 CORRIDOR FROM SUMTER COUNTY TO  
LEE COUNTY. THEREFORE, I'LL ADD MENTION FOR SEVERE STORMS CAPABLE  
OF PRODUCING DAMAGING WIND, HAIL AND A FEW TORNADOES TO THE  
HAZARDOUS WEATHER OUTLOOK FOR WEDNESDAY INTO THURSDAY. IT'S  
PROBABLE THAT ANY THREAT AREA HIGHLIGHTED WILL NEED TO BE SHIFTED  
NORTH OR SOUTH IN THE COMING DAYS DEPENDING ON HOW THIS SYSTEM  
PLAYS OUT.  
 
AFTER THE FRONT MOVES THROUGH BY THURSDAY, WE'LL LIKELY SEE SOME  
WRAP-AROUND MOISTURE FROM THE TROUGH/UPPER LEVEL LOW, WHICH WILL  
LEAD TO PERSISTENT RAIN CHANCES THROUGH AT LEAST FRIDAY. HOWEVER,  
THUNDERSTORMS CHANCES WILL BE MINIMAL BY THIS POINT AS COOLER/MORE  
STABLE AIR BUILDS IN.  
 
25/OWEN  
 

 
   
AVIATION
 
 
00Z TAF DISCUSSION.  
 
A DRY AND STABLE AIR MASS WILL HOLD OVER ALABAMA THRU THE PERIOD.  
A SFC HIGH WILL PUSH EAST OF THE AREA OVERNIGHT AND LOW LEVEL  
WINDS WILL BECOME SOUTHEAST 5-7 KTS AFTER 15Z. DESPITE A SOUTHEAST  
FLOW, THERE WILL NOT BE AN APPRECIABLE INCREASE IN LOW LEVEL  
MOISTURE TO PRODUCE CUMULUS CLOUDS DURING THE DAY SUNDAY. WITH  
WARMER TEMPERATURES OVERNIGHT AND INCREASING BOUNDARY LAYER WINDS,  
FOG WILL LIKELY BE CONFINED TO VALLEY LOCATIONS ACROSS EAST  
ALABAMA, AND INCLUDED A TEMPO 3 MILES FOG AT ANB/ASN.  
 
NOTE: AMD NOT SKED IS APPENDED AT KBHM DUE TO ASOS POWER LOSS UNTIL  
FURTHER NOTICE.  
 
58/ROSE  
 

 
   
FIRE WEATHER
 
 
RH VALUES WILL FALL INTO THE 35 TO 45 PERCENT RANGE SUNDAY  
AFTERNOON AS TEMPERATURES INCREASE AHEAD OF A COLD FRONT. LIGHT  
WINDS WILL INCREASE FROM THE SOUTHEAST TO SOUTH TOMORROW AT  
6-10MPH DURING THE AFTERNOON. RAIN CHANCES RETURN EARLY MONDAY AS  
A COLD FRONT QUICKLY MOVES THROUGH THE REGION DURING THE DAY.  
DRIER CONDITIONS ON TUESDAY QUICKLY BECOME WET AGAIN WITH THE  
NEXT SYSTEM IN THE WEDNESDAY-THURSDAY TIMEFRAME.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GADSDEN 46 80 59 78 49 / 0 0 10 50 0  
ANNISTON 49 80 62 81 52 / 0 0 10 50 0  
BIRMINGHAM 54 81 62 80 52 / 0 0 10 40 0  
TUSCALOOSA 55 82 64 82 54 / 0 0 10 40 0  
CALERA 52 80 64 80 54 / 0 0 10 40 0  
AUBURN 53 78 61 80 55 / 0 0 0 40 0  
MONTGOMERY 52 82 64 85 57 / 0 0 0 30 0  
TROY 52 82 62 85 58 / 0 0 10 30 0  
 

 
   
BMX WATCHES/WARNINGS/ADVISORIES/
 
 
NONE.  
 

 
 

 
 
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