Area Forecast Discussion
Issued by NWS Birmingham, AL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KBMX 251533
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1033 AM CDT MON MAY 25 2015

.UPDATE...
MORNING UPDATE.

&&

.DISCUSSION...

SHOWERS AND A FEW STORMS COVER A GOOD PORTION OF WESTERN ALABAMA
AS A SHORTWAVE TROUGH MOVES THROUGH THE MID-MISSISSIPPI AND
TENNESSEE RIVER VALLEYS. EXPECT THIS ACTIVITY WILL SLOWLY TRACK TO
THE EAST DURING THE DAY. TEMPERATURES ARE CURRENTLY IN THE 70S
ACROSS THE AREA THANKS TO WIDESPREAD CLOUD COVER AND INCOMING
PRECIPITATION. SOME OF THE MODELS INDICATE RATHER IMPRESSIVE
SBCAPE VALUES THIS AFTERNOON OF AROUND 2000-2500 J/KG ACROSS
SOUTHEASTERN PORTIONS OF CENTRAL ALABAMA BUT DO NOT THINK THESE
VALUES WILL BE REALIZED THANKS TO THE CLOUD COVER. DEEP LAYER
0-6KM SHEAR VALUES ARE IN THE 40KT RANGE. THEREFORE...EXPECT THERE
COULD BE A FEW STRONGER STORMS WITH SOME OF THEM APPROACHING
SEVERE LIMITS BUT WILL HOLD OFF ON MENTIONING ANYTHING IN THE HWO.
TEMPERATURES AND POPS WILL CONTINUE TO BE UPDATED THROUGHOUT THE
DAY AS THE SHOWERS AND STORMS MOVE TO THE EAST.

05/MA

&&

.AVIATION...
12Z TAF DISCUSSION.

MVFR CIGS ON E/ESE FLOW FLIRTING WITH ANB/ASN...BUT ANY CIGS
SHOULD DISSIPATE NEXT COUPLE OF HOURS. AXIS OF SHOWERS/TSTMS AHEAD
OF UPPER IMPULSE WILL SPREAD INTO W AL THIS MORNING...AND ADDED
HEATING OF THE DAY SHOULD SEE SIGNIFICANT INCREASE IN SHOWER/TSTM
LATE MORNING AND EARLY AFTN. GAVE ALL TAF SITES A 2 HOUR WINDOW OF
MOST LIKELY TSTM ACTIVITY WITH MVFR CIGS...BUT AMDS WILL LIKELY BE
NECESSARY. EXPCT SHOWERS TO GRADUALLY DISSIPATE THROUGH THE
EVENING HOURS.

LEFT OVER MOISTURE OVERNIGHT TONIGHT WITH DIMINISHING BL WINDS
POINTS TOWARDS MORE OF A FOG/HAZE SITUATION THAN CIGS...BUT WILL
DEFER THAT FORECAST TO SUBSEQUENT TAF SETS.

JD/02


&&

.PREV DISCUSSION...
/ISSUED 337 AM CDT MON MAY 25 2015/
SHORT TERM...TODAY AND TUESDAY.

AS FORECAST BY THE MODELS...MOST OF THE RAIN HAS BEEN CONFINED TO
THE STATE OF MISSISSIPPI OVERNIGHT...NEAR THE LEADING EDGE OF A
SLOW MOVING SHORT WAVE TROF. THE SHORT WAVE TROF WILL CONTINUE TO
TRACK EASTWARD AND EXPECT WIDESPREAD SHOWERS AND THUNDERSTORMS
OVER WEST ALABAMA BY SUNRISE. AS THE DAY PROGRESSES...DIURNAL
HEATING WILL LEAD TO ADDITIONAL CONVECTIVE DEVELOPMENT ACROSS THE
REMAINDER OF CENTRAL ALABAMA. STEERING LEVEL WINDS ARE RUNNING
ABOUT 190 DEGREES...AND THIS WILL RESULT IN TRAINING OF CELLS AND
LOCALIZED HEAVY RAINFALL. FLASH FLOOD GUIDANCE IS RATHER HIGH WITH
1 HOUR GUIDANCE IN THE 2.5-3 INCH RANGE...SO A FLASH FLOOD WATCH
WILL NOT BE ISSUED AT THIS TIME. THE BETTER COVERAGE OF CONVECTION
SHOULD SHIFT INTO EASTERN ALABAMA THIS AFTERNOON AS SHORT WAVE
TROF AXIS LIFTS NORTHEAST. WITH LOSS OF DAYTIME HEATING AND
WEAKENING OF SHORT WAVE TROF...CONVECTION SHOULD DIMINISH QUICKLY
THIS EVENING.

MORE SHOWERS AND THUNDERSTORMS EXPECTED ON TUESDAY AS ANOTHER
IMPULSE ROTATES OUT OF UPPER TROF OVER THE MIDWEST STATES. THE
GFS IS INDICATING AN AREA OF HIGHER 0-6KM BULK SHEAR MOVING INTO
NW ALABAMA TUESDAY AFTERNOON. ALONG WITH COOLER MID LEVEL
TEMPERATURES...GFS SURFACE BASED CAPE VALUES ARE NEAR 2500 J/KG.
THE NAM AND ECMWF MODELS ARE NOT AS ROBUST AS THE GFS. GIVEN
EXPECTED CLOUD COVER AND ONGOING SHOWERS AND THUNDERSTORMS OVER
WEST ALABAMA TUESDAY MORNING...CONFIDENCE IS RATHER LOW THAT THE
AIR MASS WILL BE ABLE TO DESTABILIZE ENOUGH BY AFTERNOON FOR THE
POSSIBILITY OF SEVERE STORMS...AND WILL NOT MENTION ANY SEVERE
THREAT AT THIS TIME.

LONG TERM...WEDNESDAY THROUGH SUNDAY.

CENTRAL ALABAMA WILL REMAIN UNDER THE INFLUENCE OF A BROAD UPPER
TROF AXIS ON WEDNESDAY. WITH PRECIPITABLE WATER VALUES NEAR 1.7
INCHES...EXPECT NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP
DURING AFTERNOON HEATING. PRECIPITABLE WATER VALUES WILL REMAIN
ABOVE NORMAL THROUGH THE WEEKEND. ON THURSDAY AND FRIDAY...AN UPPER
HIGH WILL BUILD OVER THE SOUTHEAST STATES AS A SHORT WAVE TROF
DEVELOPS OVR THE SOUTHERN PLAINS STATES. THIS WILL LEAD TO LESS
DIURNAL ACTIVITY OVER CENTRAL ALABAMA AND WARMER DAYTIME
TEMPERATURES. OVER THE WEEKEND...A LOW LEVEL RIDGE DEVELOPS OVER
THE GULF COAST REGION AND BETTER RAIN CHANCES WILL SHIFT TO THE
NORTHERN HALF OF ALABAMA.

58/ROSE

&&

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

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.