Red Flag Warning 25, NWS Birmingham, AL

Autauga County, AL, Barbour County, AL, Bibb County, AL, Blount County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Dallas County, AL, Elmore County, AL, Etowah County, AL, Fayette County, AL, Greene County, AL, Hale County, AL, Jefferson County, AL, Lamar County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Marion County, AL, Montgomery County, AL, Perry County, AL, Pickens County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
403 AM CST MON DEC 22 2008

.SHORT TERM...TODAY THROUGH TUESDAY.
TODAY WILL START OUT AS THE COLDEST MORNING SINCE AT LEAST LAST
FEBRUARY FOR MANY AREAS.  A STEADY NORTH WIND WILL KEEP THE COLD
ADVECTION MACHINE GOING THROUGH THE AFTERNOON...SO DESPITE A LOT OF
SUNSHINE ITS NOT EXACTLY GOING TO FEEL TO WARM OUT THERE.  WELCOME
TO (ASTRONOMICAL) WINTER.  DEWPOINTS ARE ALSO IMPRESSIVELY
LOW...WITH SINGLE DIGITS ABOVE AND BELOW ZERO.  SEE SECTION BELOW
REGARDING FIRE WEATHER ISSUES.

SOMEWHAT TRICKY FORECAST TONIGHT AND TUESDAY...WITH RESPECT TO
TEMPERATURES. MODELS ARE FORECASTING SOME HIGH CLOUDS TO START
SPREADING IN TONIGHT...WHICH WILL CREATE LESS THAN IDEAL RADIATIONAL
COOLING CONDITIONS.  MAV AND MET MOS ARE ALSO FORECASTING SOUTHEAST
WINDS TO PICK UP LATER ON TONIGHT...WHICH ADDS TO THE
NON-RADIATIONAL COOLINGNESS.  BUT...EXPERIENCE TELLS ME THAT THE
MODELS FREQUENTLY ARE TOO QUICK IN BRINGING IN THE CLOUDS...OR ARE AT
LEAST TOO SLOW IN DROPPING TEMPERATURES IN THE EVENING BEFORE A
SURFACE HIGH SHIFTS EAST AND THE RETURN FLOW STARTS.  THEREFORE...I
UNDERCUT GUIDANCE LOWS BY A COUPLE DEGREES TONIGHT...AND PUT THE
LOWEST TEMPERATURES AROUND MIDNIGHT (WITH STEADY OR SLOWLY RISING
TEMPS AFTER THAT).

THE NEXT SERIES OF SHORTWAVES WILL START TO IMPACT THE AREA ON
TUESDAY.  SURFACE MOISTURE WILL STILL BE QUITE LIMITED THROUGH MOST
OF THE DAY ON TUESDAY.  HECK...WELL STILL BE RECOVERING FROM
DEWPOINTS IN THE SINGLE DIGITS JUST 24 HOURS PRIOR.  I THINK THE
MODEL POPS ON TUESDAY ARE A BIT OVERDONE...AND I SCALED THEM BACK
JUST A BIT.  I ALSO DELAYED THE ONSET OF ANY RAIN CHANCES AT ALL
UNTIL MID/LATE AFTERNOON TUESDAY.

/61/

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY NIGHT.

PRONOUNCED SOUTHWEST UPPER FLOW DOMINATES MUCH OF THE PERIOD.
GFS/ECMWF/GEFS IN FAIR AGREEMENT WITH THE LARGE SCALE FLOW WITH
SOME DIVERGENCE IN SOLUTIONS NOTED AT THE VERY TAIL END OF THE
PERIOD. THE PERIOD WILL BE CHARACTERIZED BY A LARGE UPPER RIDGE
NEAR THE BAHAMAS...INCHING WESTWARD...WITH A STORM TRACK FROM THE
FOUR CORNERS TO THE GREAT LAKES. THIS PATTERN LOOKS TO KEEP
TEMPERATURES AT OR ABOVE NORMAL. RAIN CHANCES APPEAR IN SEVERAL
PERIODS AS ACTIVE PATTERN CONTINUES...SIMILAR TO THE GRAY AND RAINY
PERIOD OF A FEW DAYS AGO.

MADE A MUCH TIGHTER GRADIENT OF RAIN CHANCES TUESDAY NIGHT AS
STRONG SOUTHERLY FLOW AND ISENTROPIC LIFT MOISTEN THE ATMOSPHERE.
HAVE LIKELY LIGHT RAIN FAR NORTHWEST WITH NOTHING MENTIONED
SOUTHEAST.

COLD FRONT ENTERS NORTHWEST ALABAMA LATE WEDNESDAY AFTERNOON.
GFS/ECMWF/NAM ARE IN GOOD AGREEMENT WITH TIMING/PLACEMENT OF FRONT AS
WELL AS ATMOSPHERIC INSTABILITY AND SHEAR. WILL KEEP MENTION OF
THUNDER BUT MODELS AGREE IN LIMITED INSTABILITY/LIFT/HEIGHT FALLS
ZIPPING OFF TO THE NORTH/SHEAR DECREASING WITH TIME...SO NO MENTION
AT THIS TIME OF STRONG STORMS. WENT WITH THE CONSENSUS SLOWER
SOLUTION WHICH HAS A HIGH GRADIENT OF RAIN CHANCES AGAIN ON
WEDNESDAY AFTERNOON...NORTHWEST TO SOUTHEAST. FRONT MOVES ACROSS
MUCH OF THE FORECAST AREA WEDNESDAY NIGHT...BUT SOME LIFT WILL BE
LOST OVERNIGHT. EXPECT THE RAIN AREA TO LOSE TO COVERAGE AND
INTENSITY AS WE GO THROUGH THE NIGHT.

MODELS DISAGREE WITH HOW FAR SOUTH THE FRONT GOES BY THURSDAY
MORNING. WITH RIDGE SOUTH OF THE AREA AND NEXT SYSTEM DROPPING
SOUTHWARD OUT WEST...WILL TAKE A MIX OF THE GFS/NAM/ECMWF AND HAVE
THE FRONT TO THE SOUTHERN REACHES OF THE AREA THURSDAY MORNING...
RETURNING AS A WARM FRONT AS SOUTHERLY FLOW RETURNS FRIDAY.
THEREFORE...RAIN CHANCES REMAIN EACH DAY.

NEXT COLD FRONT SLATED FOR SATURDAY AFTERNOON INTO EARLY SUNDAY. WILL
INCREASE RAIN CHANCES THIS PERIOD. UPPER RIDGE TO THE SOUTH WEAKENS
A BIT BY THIS TIME...SO FRONT SHOULD MOVE A BIT FARTHER SOUTH AND
CLEAR THE AREA...BUT LURK CLOSE TO THE SOUTH. WILL FORECAST DRY
CONDITIONS MUCH OF SUNDAY AND MONDAY AT THIS TIME. NOT MUCH
CONFIDENCE IN THE ATMOSPHERIC STABILITY NUMBERS FOR FRIDAY AND
BEYOND...BUT THIS PERIOD IS WORTH KEEPING AND EYE ON FOR STRONGER
STORMS.

75/LINHARES

&&

.AVIATION...06Z TAF DISCUSSION.

VFR CONDITIONS WILL PREVAIL WITH NORTH WINDS 10-15 KNOTS THRU 15Z
THEN BECOMING 8-10 KNOTS.

58

&&

.FIRE WEATHER...RELATIVE HUMIDITY VALUES WILL DROP BELOW 25
PERCENT FOR SEVERAL HOURS TODAY AND A RED FLAG WARNING HAS BEEN
POSTED FOR THE ENTIRE AREA.

75

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     38  22  51  47  68 /   0   0  10  20  40
ANNISTON    41  26  54  45  69 /   0   0  10  20  40
BIRMINGHAM  37  27  53  50  68 /   0   0  20  30  40
TUSCALOOSA  41  28  54  54  71 /   0   0  20  30  50
CALERA      42  27  54  50  70 /   0   0  10  20  40
AUBURN      42  24  55  44  69 /   0   0  10  10  20
MONTGOMERY  44  28  62  53  74 /   0   0  10  10  40
TROY        46  26  58  51  73 /   0   0  10  10  20

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FOR ALL OF CENTRAL ALABAMA FROM 9 AM THROUGH 6 PM.

&&

61/75/58

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
740 PM CST SUN DEC 21 2008

ALZ011>015-017>050-221300-
AUTAUGA-BARBOUR-BIBB-BLOUNT-BULLOCK-CALHOUN-CHAMBERS-CHEROKEE-
CHILTON-CLAY-CLEBURNE-COOSA-DALLAS-ELMORE-ETOWAH-FAYETTE-GREENE-HALE-
JEFFERSON-LAMAR-LEE-LOWNDES-MACON-MARENGO-MARION-MONTGOMERY-PERRY-
PICKENS-PIKE-RANDOLPH-RUSSELL-SHELBY-ST CLAIR-SUMTER-TALLADEGA-
TALLAPOOSA-TUSCALOOSA-WALKER-WINSTON-
740 PM CST SUN DEC 21 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE COUNTIES SERVED BY THE
NATIONAL WEATHER SERVICE OFFICE IN BIRMINGHAM.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

A FIRE WEATHER WATCH HAS BEEN ISSUED FOR ALL OF CENTRAL ALABAMA FROM
9 AM THROUGH 6 PM MONDAY.  OUTDOOR BURNING IS HIGHLY DISCOURAGED.

CONDITIONS WILL BE COLD MONDAY MORNING...WITH TEMPERATURES DROPPING
INTO THE TEENS AND 20S. WIND CHILL WILL BE BETWEEN 5 AND 15 DEGREES
FOR MUCH OF CENTRAL ALABAMA.

ANOTHER STORM SYSTEM WILL BRING WINDY CONDITIONS TO CENTRAL
ALABAMA AGAIN ON WEDNESDAY. A LAKE WIND ADVISORY MAY BE REQUIRED.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT IS NOT
EXPECTED.