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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