National Weather Service Weather Forecast Office

Area Forecast Discussion

349
FXUS64 KBMX 221159
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
659 AM CDT WED MAY 22 2013

.UPDATE...
FOR 12Z AVIATION.

&&

.DISCUSSION...

VERY COMPLICATED FORECAST OVER THE NEXT 24 HOURS OR SO. LINE OF
TSTORMS THAT MOVED IN FROM MS WEAKENED SIGNIFICANTLY AS THEY
APPROACHED THE STATE LINE AND ENTERED AL AS THE OUTFLOW RUSHED OUT
AHEAD OF THE STORMS. IN FACT..THE OUTFLOW WAS THE MAIN FEATURE
WORTH WATCHING AS IT ENTERED THE CWA. HOWEVER THE WINDS REMAINED
WELL BELOW SEVERE CRITERIA. THE INITIAL ACTIVITY CONTINUES TO
DISSIPATE AS ADDITIONAL DEVELOPMENT IS NOW TAKING PLACE ACROSS N
AL ALONG THE OUTFLOW BOUNDARY. MEANWHILE A LOW STRATUS DECK IS
SPREADING NORTHWARD ACROSS THE SOUTHERN COUNTIES AND COULD LEAD
TO SOME REDUCTIONS IN VIS.

ACTUAL COLD FRONT IS STILL WELL BACK TO OUR WEST ACROSS AR. EXPECT
CONVECTION TO INITIATE ALONG AND AHEAD OF THE FRONT THIS MORNING
AND THEN PUSH EAST/SOUTHEAST ACROSS CENTRAL ALABAMA DURING THE DAY WITH
FRONTAL PASSAGE. BELIEVE THE BEST RAIN CHANCES WILL REMAIN
CONFINED TO THE NORTHWESTERN HALF OF THE CWA. COVERAGE SHOULD
DECREASE THRU THE EVENING WITH ONLY A FEW ISO SHOWERS/STORMS IN
THE SE COUNTIES BY TONIGHT. WILL CONTINUE TO LEAVE MENTION OF
SEVERE OUT OF THE HWO DUE TO OVERALL LACK OF ATMOSPHERIC SUPPORT
FOR ANYTHING MORE THAN PERHAPS A STRONG STORM OR TWO WITH GUSTY WINDS.

ANOTHER SHORTWAVE WILL ROTATE ACROSS THE AREA ON THURSDAY AND
COULD LEAD TO SOME ISO DEVELOPMENT...MAINLY IN THE AFTERNOON. THIS
FEATURE WILL USHER IN A MUCH DRIER AIR MASS FROM THE NORTH WITH
DEW POINTS FALLING INTO THE 50S...AND MAYBE UPPER 40S IN THE
NORTH...BY FRIDAY. FOR THOSE OF YOU WHO ARE OPPOSED TO 90 DEGREE
WEATHER THEN YOU`LL ENJOY FRIDAY. TEMPS WILL BE BELOW NORMAL WITH
HIGHS RANGING FROM THE MID 70S NORTH TO LOW/MID 80S SOUTH.

SFC HIGH PRESSURE WILL KEEP CONDITIONS DRY THROUGH AT LEAST THE
WEEKEND WITH TEMPS WARMING BACK INTO THE MID/UPPER 80S BY SUNDAY.
STILL SOME QUESTIONS REGARDING THE SETUP EARLY NEXT WEEK. NW FLOW
ALOFT USUALLY SPELLS TROUBLE DUE TO UNCERTAINTY IN THE TRACKS OF
ANY UPPER LEVEL IMPULSES. DUE TO MODEL DISCREPANCIES WILL KEEP THE
FORECAST DRY IN THE EXTENDED FOR NOW.


&&

.AVIATION...
12Z TAF DISCUSSION.

A DIFFICULT AVIATION FORECAST WILL EXIST TODAY...AS CURRENT RADAR
TRENDS ARE PRESENTING VERY LIGHT SHOWERS ACROSS NORTHERN PORTIONS
OF CENTRAL ALABAMA...WHILE MORE IN THE WAY OF RAINFALL IS
CURRENTLY ONGOING ACROSS SOUTHWESTERN ALABAMA AND SOUTHERN
MISSISSIPPI IN ASSOCIATION WITH A LARGE OUTFLOW BOUNDARY.
MEANWHILE...LOW IFR TO LIFR STRATUS WITH PATCHY DENSE FOG HAS
DEVELOPED ACROSS ALL OF SOUTHERN ALABAMA OVER THE PAST HOUR. THE LOW
STRATUS CLOUDS AND FOG ARE EXPECTED TO CONTINUE THROUGH THE MID
MORNING HOURS BEFORE FINALLY DISSIPATING TO VFR BY THIS AFTERNOON.
IN TERMS OF THE FORECAST FOR ALL OF THE TERMINALS THIS
AFTERNOON...SHOWERS WILL REMAIN POSSIBLE AS A COLD FRONT
APPROACHES FROM THE NORTHWEST. HOWEVER...CONFIDENCE IN THE AMOUNT
OF SHRA COVERAGE IS LOW AT THIS TIME DUE TO MODEL GUIDANCE
DISAGREEMENTS AND THE LARGE MASS OF RAIN TO OUR SOUTHWEST...WHICH
WILL HELP TO CUT OFF MOISTURE TRANSPORT FOR WIDESPREAD SHOWER AND
THUNDERSTORM DEVELOPMENT. FOR NOW...I HAVE DECIDED TO GO WITH A
VCSH FOR ALL TAFS INSTEAD OF VCTS. ALSO...WITH LOWER CONFIDENCE IN
OVERALL COVERAGE...PREVAILING RA OR TSRA ARE NOT BEING INCLUDED AT
THIS TIME. AMENDMENTS WILL POSSIBLY BE NEEDED THROUGHOUT THE DAY
BASED ON WHERE SHOWERS OR STORMS DEVELOP AND PROPAGATE. WINDS WILL
PREVAIL FROM THE SOUTHWEST THIS AFTERNOON AND REMAIN FAIRLY LIGHT.

56/GDG

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     82  63  83  57  77 /  50  30  20  10   0
ANNISTON    84  64  84  59  78 /  40  30  20  10   0
BIRMINGHAM  82  64  84  60  78 /  50  30  20  10   0
TUSCALOOSA  82  63  87  61  81 /  50  30  20  10   0
CALERA      83  65  84  60  80 /  40  30  20  10   0
AUBURN      87  66  84  61  80 /  30  40  20  10   0
MONTGOMERY  88  67  88  63  84 /  30  40  20  10   0
TROY        88  67  88  63  84 /  30  40  20  10   0

&&

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

&&

$$