Severe Thunderstorm Warning 197, NWS Birmingham, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
629 AM CDT SUN MAY 3 2009

.UPDATE...12Z AVIATION DISCUSSION.

&&

.DISCUSSION...

THUNDERSTORMS WERE A LITTLE MORE ACTIVE ACROSS NORTH ALABAMA ON
SATURDAY THAN EXPECTED...AND TODAY SHOULD BE ANOTHER ACTIVE PERIOD
FOR SEVERE WEATHER. A QUASI- STATIONARY SURFACE BOUNDARY WILL
REMAIN ACROSS NORTHWEST ALABAMA DURING THE DAY TODAY...AND PROVIDE
A FOCUS FOR CONVECTION. THE FIVE NORTHWEST COUNTIES HAVE ALREADY
EXPERIENCED 2-3 INCHES OF RAINFALL IN THE PAST 12 HOURS...AND AN
ADDITIONAL 2-4 INCHES POSSIBLE THROUGH THIS EVENING. THE FLASH
FLOOD WATCH WILL BE EXTENDED FOR THOSE COUNTIES THROUGH TONIGHT.

MODELS HAVE BEEN VERY CONSISTENT IN SHOWING INCREASING LOW LEVEL
INFLOW AHEAD OF DEVELOPING SURFACE FRONTAL WAVE. SEVERAL BANDS OF
INTENSE CONVECTION WILL DEVELOP AHEAD OF SURFACE WAVE WITH THE
FIRST WAVE REACHING NORTHWEST ALABAMA BY MID AFTERNOON...WITH
ADDITIONAL BAND OF CONVECTION CONTINUING WELL INTO THE EVENING.
FORECAST WIND PROFILES INDICATE THERE WILL BE SUFFICIENT SHEAR FOR
ISOLATED TORNADOES EMBEDDED IN BOW SEGMENTS. STORMS SHOULD WEAKEN
BY 06Z AS SURFACE WAVE MOVES OUT OF AREA AND LOW LEVEL INFLOW
RELAXES.

STALLED OUT FRONTAL BOUNDARY ACROSS NORTH ALABAMA WILL BE TRIGGER
FOR ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT ON MONDAY.
CLOUD COVER AND WEAKER WIND FLOW SHOULD LIMIT INSTABILITY AND WILL
CONTINUE WITH ONLY STRONG THUNDERSTORM WORDING IN HAZARDOUS.
FLATTENING OUT OF UPPER TROF WILL KEEP SURFACE FRONT FROM EXITING
AREA BUT IT SHOULD PUSH DEEPER MOISTURE INTO SOUTHERN ALABAMA ON
TUESDAY. MOISTURE WILL QUICKLY PUSH BACK NORTHWARD ON WEDNESDAY AS
A FAST MOVING SHORT WAVE TROF PASSES TO THE NORTH OF ALABAMA.
THERE COULD BE A SHORT BREAK IN THE RAIN ON THURSDAY BEFORE
ANOTHER FAST MOVING SHORT WAVE TROF APPROACHES AREA. THIS SYSTEM
MAY HAVE ENOUGH UPPER LEVEL SUPPORT TO PUSH A WEAK COLD FRONT
THROUGH AREA LATE FRIDAY OR SATURDAY...AND WILL SHOW A DRYING
TREND GOING INTO THE WEEKEND.

&&

.AVIATION...12Z TAF DISCUSSION.

SHOWERS AND THUNDERSTORMS WILL MOVE INTO WEST CENTRAL ALABAMA BY MID
MORNING AND CONTINUE THROUGH MUCH OF THE DAY...AFFECTING ALL
TERMINALS. ACTIVITY SHOULD HOLD OFF AT MGM AND TOI TIL MID
AFTERNOON. ACTIVITY WILL BEGIN TO DIMINISH AFTER 03Z. GUSTY WINDS
WILL BE POSSIBLE...WITH MVFR CONDITIONS DURING STRONGER STORMS...AND
BRIEF PERIODS OF IFR VIS POSSIBLE.

14

&&

.BMX WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH NORTHWEST
COUNTIES TODAY AND TONIGHT.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1145 AM CDT SUN MAY 3 2009

ALZ011>015-017>050-041645-
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-
1145 AM CDT SUN MAY 3 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SEVERE STORMS ARE LIKELY ACROSS AREAS GENERALLY ALONG AND SOUTH OF A
LINE FROM VERNON TO HEFLIN.  THE MAIN THREATS WITH THESE STORMS WILL
BE STRONG DAMAGING WINDS...HAIL...AND ISOLATED TORNADOES.  THE FIRST
AND PRIMARY THREAT WILL BE FROM 1 PM UNTIL 5 PM.  HOWEVER...A
SECONDARY LINE OF SEVERE THUNDERSTORMS IS ALSO POSSIBLE LATER THIS
EVENING AND THROUGH THE OVERNIGHT HOURS.

THERE IS ALSO THE THREAT OF FLASH FLOODING ACROSS NORTH CENTRAL
ALABAMA. DUE RECENT HEAVY RAINFALL ACROSS NORTHWEST ALABAMA...THIS
AREA HAS BETTER CHANCES FOR FLASH FLOODING THIS AFTERNOON AND
TONIGHT...BUT AREAS OUTSIDE THE FLASH FLOOD WATCH COULD EXPERIENCE
FLOODING IF STORMS TRAIN OVER THE SAME AREA.

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

STRONG THUNDERSTORMS ARE POSSIBLE ACROSS SOUTH CENTRAL ALABAMA
MONDAY AFTERNOON. THE MAIN THREAT IS WIND GUSTS OF 35 TO 45 MPH
AND SMALL HAIL.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT WILL LIKELY
BE NECESSARY TODAY.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
930 AM CDT SUN MAY 3 2009

ALZ022-030-031-031530-
GREENE-PICKENS-SUMTER-
930 AM CDT SUN MAY 3 2009

...SIGNIFICANT WEATHER ALERT FOR GREENE...PICKENS AND SUMTER COUNTIES
UNTIL 1030 AM CDT...

AT 930 AM CDT...THE NATIONAL WEATHER SERVICE IS TRACKING STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM PANOLA TO 18 MILES WEST OF
CUBA...OR ALONG A LINE EXTENDING FROM 10 MILES SOUTHWEST OF
ALICEVILLE TO 18 MILES WEST OF CUBA...MOVING EAST AT 25 MPH.

WINDS UP TO 50 MPH AND HEAVY DOWNPOURS ARE EXPECTED WITH THESE
STORMS.

* LOCATIONS IN OR NEAR THE PATH INCLUDE...
  MEMPHIS.
  PANOLA.
  GEORGE DOWNER AIRPORT.
  ALICEVILLE.
  EMELLE.
  PLEASANT RIDGE.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 300 PM CDT SUNDAY
AFTERNOON FOR SOUTHWESTERN ALABAMA.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1055 AM CDT SUN MAY 3 2009

ALZ030>032-031645-
GREENE-HALE-SUMTER-
1055 AM CDT SUN MAY 3 2009

...SIGNIFICANT WEATHER ALERT FOR GREENE...HALE AND SUMTER COUNTIES
UNTIL 1145 AM CDT...

AT 1052 AM CDT...THE NATIONAL WEATHER SERVICE IS TRACKING A STRONG
THUNDERSTORM NEAR BLUFFPORT...OR 6 MILES EAST OF LIVINGSTON...MOVING
NORTHEAST AT 35 MPH.

PEA SIZE HAIL AND WINDS UP TO 50 MPH ARE EXPECTED WITH THIS STORM.

* LOCATIONS IN OR NEAR THE PATH INCLUDE...
  BLUFFPORT.
  TISHABEE.
  BOLIGEE.
  THORNHILL.
  FORKLAND.
  WALDEN QUARTERS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 300 PM CDT SUNDAY
AFTERNOON FOR SOUTHWESTERN ALABAMA.

STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL
TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERNING THIS WEATHER SITUATION.