Flash Flood Warning 5, NWS Birmingham, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
333 AM CDT SAT MAR 23 2013

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.

AN UPPER LEVEL IMPULSE MOVING THROUGH ARKANSAS HAS BEEN PRODUCING
A CLUSTER OF THUNDERSTORMS ACROSS NORTHERN MISSISSIPPI. THE STORMS
ARE ELEVATED AS SURFACE TEMPERATURES ARE CURRENTLY IN THE 40S
ACROSS NORTHERN MISSISSIPPI AND ALABAMA. A FEW OF THE STORMS COULD
PRODUCE LARGE HAIL ACROSS NORTHWEST ALABAMA EARLY THIS MORNING DUE
TO 500MB TEMPS NEAR -18 CELSIUS. THIS CLUSTER OF STORMS WILL
AFFECT AREAS ALONG AND NORTH OF I-20 THRU THE MID MORNING HOURS.
FARTHER TO THE SOUTH THE PRIMARY FORCING MECHANISM FOR CONVECTION
TODAY WILL LIKELY BE DIURNAL HEATING...WHICH MEANS ANY CONVECTION
WILL BE MAINLY DURING THE AFTERNOON HOURS. THE SURFACE WARM FRONT
AND MORE UNSTABLE AIR MASS WILL STAY SOUTH OF CENTRAL ALABAMA THIS
AFTERNOON...AND ANY SEVERE STORMS WILL BE CONFINED TO THE EXTREME
SOUTHERN COUNTIES.

THE MODELS ARE STILL STRUGGLING TO BRING THE SURFACE WARM FRONT
NORTHWARD TONIGHT DUE TO WEAK SURFACE CYCLOGENESIS WEST OF ALABAMA.
THE TORNADO THREAT IS TIED TO THE LOCATION OF THE WARM FRONT AND
SO THE THREAT AREA WILL REMAIN CONFINED TO THE SOUTHERN HALF OF
CENTRAL ALABAMA. NORTH OF THE WARM FRONT...THE PRIMARY THREAT WILL
LIKELY BE LARGE HAIL...AS THE SURFACE BASED LIFTED INDICES STAY
POSITIVE FOR MOST OF THE NIGHT...WITH ANY INSTABILITY ELEVATED
ABOVE THE BOUNDARY LAYER. SUNDAY IS LOOKING MORE INTERESTING AS
THE SURFACE FRONT PUSHES THROUGH THE AREA. SURFACE TEMPERATURES
WILL WARM INTO THE MIDDLE 60S TO MIDDLE 70S ACROSS EAST ALABAMA.
COMBINED WITH COLD TEMPERATURES ALOFT...LIFTED INDICES ARE
FORECAST TO FALL TO THE -5 TO -7 CELSIUS RANGE...WITH SURFACE
BASED CAPE VALUES AROUND 1500 J/KG. MOISTURE WILL BE LIMITED AS
PRECIPITABLE WATER VALUES FALL BELOW ONE INCH...BUT ANY STORMS
THAT CAN GET GOING COULD PRODUCE LARGE HAIL. A THIS TIME...WILL
NOT MENTION SEVERE STORMS FOR SUNDAY...BUT IT IS SOMETHING THAT
WILL NEED TO BE MONITORED IN FUTURE OUTLOOKS.

SURFACE WINDS WILL INCREASE OUT OF THE WEST SUNDAY AFTERNOON AS
THE PRESSURE GRADIENT INCREASES ON THE BACK SIDE OF THE EXITING
SURFACE LOW...AND A WIND ADVISORY WILL LIKELY BE REQUIRED IN LATER
FORECASTS.

58/ROSE

.LONG TERM...MONDAY THROUGH FRIDAY.

A MUCH COLDER AIR MASS WILL OVERSPREAD CENTRAL ALABAMA FOR THE
FIRST HALF OF THE WORK WEEK. MONDAY AND TUESDAY WILL BE THE
COLDEST DAYS OF THE WEEK WITH HIGH TEMPERATURES 15-20 DEGREES
BELOW AVERAGE. SOME AREAS ACROSS NORTH ALABAMA MAY NOT GET OUT OF
THE 40S FOR DAYTIME HIGHS. LOW TEMPERATURES WILL ALSO FALL TO NEAR
OR JUST BELOW FREEZING TUESDAY AND WEDNESDAY MORNINGS FOR A LARGE
PORTION OF CENTRAL ALABAMA. SKIES WILL BE MOSTLY CLEAR DURING THE
WEEK...BUT A DECK OF LOWER CLOUDS WILL LIKELY ADVECT INTO NORTH
ALABAMA MONDAY NIGHT AND TUESDAY MORNING...AND WOULD NOT BE
SURPRISED TO SEE A FEW SNOW FLURRIES. A NICE WARM-UP BY THE END OF
THE WEEK WITH HIGHS IN THE UPPER 60S TO LOWER 70S BY FRIDAY.

58/ROSE

&&

.AVIATION...
06Z TAF DISCUSSION.

WILL SEE A CONTINUATION OF MVFR CIGS THROUGH MUCH OF THE NEXT 24
HOURS. A ROUND OF SHOWERS AND THUNDERSTORMS MAY AFFECT THE
NORTHERN HALF OF THE AREA BEGINNING BEFORE DAYBREAK AND TEMPORARY
IFR CONDITIONS COULD OCCUR. A BREAK IN THE RAIN IS EXPECTED BY
LATE MORNING BEFORE A MORE INTENSE ROUND OF THUNDERSTORMS AND
WORSENING FLIGHT CONDITIONS SET IN AFTER 00Z.

87/GRANTHAM

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     58  50  63  35  48 /  80 100  60  10  10
ANNISTON    59  52  68  35  49 /  80 100  60  10  10
BIRMINGHAM  62  53  65  34  50 /  70 100  50  10  10
TUSCALOOSA  63  55  67  35  52 /  70 100  30  10  10
CALERA      63  55  67  36  51 /  70 100  40  10  10
AUBURN      63  55  72  37  52 /  70 100  60  10  10
MONTGOMERY  68  61  75  38  55 /  70 100  40  10  10
TROY        68  61  75  38  54 /  70 100  40   0  10

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
929 PM CDT FRI MAR 22 2013

ALZ011>015-017>050-240230-
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-
929 PM CDT FRI MAR 22 2013

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...SATURDAY THROUGH THURSDAY.

THERE IS A RISK OF SEVERE THUNDERSTORMS LATE SATURDAY AFTERNOON
INTO EARLY SUNDAY WITH DAMAGING WINDS AND LARGE HAIL POSSIBLE
ACROSS ALL OF CENTRAL ALABAMA. AN ISOLATED TORNADO THREAT MAY
DEVELOP LATE IN THE EVENING AND INTO THE OVERNIGHT HOURS GENERALLY
NEAR AND SOUTH OF A LINE FROM LIVINGSTON TO CLANTON TO AUBURN.

WINDY CONDITIONS ARE POSSIBLE SUNDAY AFTERNOON BEHIND THE EXITING
COLD FRONT. SUSTAINED WINDS AROUND 20 MPH WITH GUSTS OF 30
TO 40 MPH WILL BE POSSIBLE.

A MUCH COOLER AIR MASS WILL MOVE INTO THE REGION EARLY NEXT WEEK.
SUB FREEZING TEMPERATURES ARE POSSIBLE ON BOTH MONDAY AND TUESDAY
NIGHTS.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTERS AND EMERGENCY MANAGEMENT SHOULD START PLANNING FOR
POSSIBLE ACTIVATION BEGINNING SATURDAY AFTERNOON INTO EARLY SUNDAY
MORNING...DUE TO THE THREAT OF SEVERE WEATHER.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
254 AM CDT SAT MAR 23 2013

ALZ011-230845-
MARION AL-
254 AM CDT SAT MAR 23 2013

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN MARION COUNTY UNTIL
345 AM CDT...

AT 254 AM CDT...THE NATIONAL WEATHER SERVICE WAS TRACKING A STRONG
THUNDERSTORM NEAR FULTON...MOVING EAST AT 65 MPH.

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 40 MPH HAVE
BEEN REPORTED WITH THIS STORM.

LOCATIONS IN OR NEAR THE PATH OF THIS STORM INCLUDE...
  SHOTTSVILLE...
  PIGEYE...

&&

LAT...LON 3432 8813 3432 8803 3432 8788 3431 8788
      3423 8819 3432 8818 3433 8817 3433 8814
TIME...MOT...LOC 0754Z 250DEG 55KT 3430 8830

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