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000
FXUS64 KBMX 130306 AAB
AFDBMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1006 PM CDT WED JUN 12 2013

.UPDATE...
FOR EVENING FORECAST.

&&

.DISCUSSION...

HAVE REMOVED THE ISOLATED POPS FROM THE FORECAST AS ACTIVITY TO
OUR EAST WAS DIURNALLY BASED AND FIZZLED QUICKLY AFTER SUNSET
NEVER GETTING INTO CENTRAL ALABAMA. PRETTY SIMILAR TEMPERATURE SET
UP. STILL EXPECTING WARMER THAN WHAT GFS MOS IS FORECASTING BUT
MORE PERSISTENCE OF A RULE FOR TONIGHT. SO ONLY MINOR TWEAKS TO
TEMPERATURES. TOMORROW NIGHT WILL BE A MUCH DIFFERENT STORY WITH
OUR TSRA EXPECTED AND FRONTAL SYSTEM. UPDATE ALREADY OUT.

08

&&

.AVIATION...
00Z TAF DISCUSSION.

FIRST 20-22 HOURS OF THE 00Z TAF FORECAST WILL BE LARGELY
PERSISTENCE BASED...WITH WINDS BECOMING CALM AND SKIES GENERALLY
CLEAR. KEPT THE MENTION OF MVFR VISIBILITIES AT BOTH TCL AND TOI AS
WELL...BUT I THINK CONDITIONS ELSEWHERE WILL REMAIN VFR.

WITH PUBLIC FORECAST POPS OF >50 PERCENT TOMORROW AFTERNOON...I WAS
COMPELLED TO PUT IN SOME THUNDERSTORMS FOR THE NORTHERN TERMINALS.
MY CONFIDENCE IN THE COVERAGE OF STORM DEVELOPMENT TOMORROW IS STILL
A BIT ON THE LOW SIDE. BUT ANY STORMS THAT DO FIRE UP COULD BRING
SIGNIFICANTLY HIGHER WINDS THAT PRESENTLY FORECAST. A LARGE PORTION
OF WHAT HAPPENS TOMORROW AFTERNOON WILL ALSO BE DEPENDENT ON WHAT
HAPPENS UPSTREAM FROM US OVERNIGHT AND THURSDAY MORNING.

/61/

&&

.PREV DISCUSSION... /ISSUED 317 PM CDT WED JUN 12 2013/

DISCUSSION...

CURRENTLY MONITORING THUNDERSTORM DEVELOPMENT ACROSS WESTERN PARTS
OF GEORGIA ON THE EASTERN FRINGE OF A MID-LEVEL RIDGE. CANNOT RULE
OUT A FEW OF THESE STORMS ENTERING OUR FAR EASTERN COUNTIES
THROUGH THE EVENING HOURS DUE TO WESTWARD OUTFLOW BOUNDARIES
CAUSING ADDITIONAL DEVELOPMENT. HAVE A 10 POP ACROSS THE EAST BUT
THIS MAY NEED TO BE ADJUSTED UPWARD LATER THIS AFTERNOON.

CONDITIONS ARE RATHER UNCOMFORTABLE THIS AFTERNOON AS DEW POINTS
HAVE BEEN RELUCTANT TO FALL BELOW 70 DEGREES. ABUNDANT SOIL
MOISTURE IS LIKELY RESPONSIBLE FOR THIS AND HAVE CONTINUED TO GO
WITH HIGHER DEW POINTS THAN MOST GUIDANCE INDICATES. MOISTURE
POOLING IS LIKELY IN THE VICINITY OF THE FRONT THAT WILL BE MOVING
IN FROM THE NORTH ON THURSDAY AFTERNOON. HEAT INDEX VALUES COULD
APPROACH 105 DEGREES IN MANY LOCATIONS BUT WILL REFRAIN FROM
ISSUING A HEAT ADVISORY.

THE MAIN CONCERN IS NOT THE HEAT ON THURSDAY BUT INSTEAD A THREAT
FOR SEVERE CONVECTION. THE ENVIRONMENT ON THURSDAY AFTERNOON AND
EVENING IN THE VICINITY OF THE FRONT WILL BE CHARACTERIZED BY
VERY STEEP LOW-LEVEL LAPSE RATES AND ABUNDANT MOISTURE FROM THE
SURFACE TO 800 MB WITH VERY DRY AIR ABOVE THAT LAYER. THIS WILL
PRODUCE SURFACE-BASED CAPE VALUES OF 3000-4000 J/KG AND STRONG TO
EXTREME DOWNDRAFT CAPE VALUES OF 1500-2000 J/KG. THESE INSTABILITY
VALUES WILL COMBINE WITH 0-6 KM SHEAR VALUES OF 30-35 KT AND
EXPLOSIVE THUNDERSTORM DEVELOPMENT IS POSSIBLE ALONG THE FRONT BY
21Z ACROSS THE NORTHERN PART OF THE CWA. THIS IDEA IS SUPPORTED
BY THE LATEST 12Z RUN OF 4 KM WRF-NMM. LARGE HAIL IS LIKELY WITH
THE INITIAL DEVELOPMENT WITH A TRANSITION TO MORE OF A DAMAGING
WIND THREAT AS STORMS GROW INTO CLUSTER OR LINES. ANY STORMS WILL
HAVE A HIGH CHANCE OF PRODUCING DAMAGING WINDS AND ISOLATED GUSTS
UP TO 80 MPH MAY OCCUR...BUT IT IS ALSO POSSIBLE THAT A MORE
WIDESPREAD WIND EVENT COULD UNFOLD THROUGH THE EVENING HOURS AS
THE ACTIVITY MOVES SOUTHWARD.

SLIGHTLY COOLER CONDITIONS AND MUCH LOWER HUMIDITY CAN EXPECTED ON
FRIDAY AND SATURDAY AS SURFACE HIGH PRESSURE MOVES IN ACROSS THE
OHIO VALLEY. MOISTURE WILL BEGIN TO INCREASE AGAIN BY SUNDAY
LEADING TO A CHANCE FOR SHOWERS AND STORMS BY MONDAY.

87/GRANTHAM

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     70  93  64  86  60 /   0  60  10   0   0
ANNISTON    72  94  66  88  63 /  10  60  20   0   0
BIRMINGHAM  74  95  66  88  66 /   0  60  20   0   0
TUSCALOOSA  73  96  68  90  65 /   0  60  30   0   0
CALERA      73  94  68  89  67 /   0  60  30   0   0
AUBURN      73  94  68  87  67 /  10  30  60   0   0
MONTGOMERY  74  97  71  92  66 /   0  20  60   0   0
TROY        72  97  71  91  66 /   0  10  60   0   0

&&

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

&&

$$

08/61/87