792 
FXUS64 KBMX 271724
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1224 PM CDT WED MAR 27 2013

.UPDATE...
FOR AVIATION.

&&

.DISCUSSION...

WITH SURFACE HIGH PRESSURE IN PLACE OVER THE DEEP SOUTH THIS 
MORNING... NO MAJOR CHANGES WERE NEEDED WITH THIS UPDATE. 12Z KBMX
SOUNDING SHOWS A DRY AND STABLE AIRMASS... AND NO PRECIP IS
EXPECTED FOR THE REST OF TODAY OR TONIGHT. MADE MINOR ADJUSTMENTS
TO SKY GRIDS FOR TODAY TO TIME THE ARRIVAL OF HIGH CIRRUS CLOUDS
MOVING IN FROM THE NORTHWEST... AND BROUGHT HOURLY TEMPS AND DEW
POINTS IN LINE WITH OBS. NO CHANGES WERE MADE TO HIGH TEMPS THIS
AFTERNOON OR LOW TEMPS TONIGHT.

A FREEZE WATCH REMAINS IN EFFECT TONIGHT FOR ALL OF CENTRAL
ALABAMA. MORE INFO ON THE POSSIBLE FREEZING TEMPERATURES OVERNIGHT
WILL COME WITH THE AFTERNOON FORECAST PACKAGE. ALSO... MAINTAINED
THE FIRE WEATHER WATCH FOR THE SOUTHERN HALF OF CENTRAL ALABAMA
FOR THIS AFTERNOON. JUST REALLY NOT SURE WE WILL MEET THE 4 HOUR
OF LESS THAN 25 PERCENT RH TIME REQUIREMENT NEEDED FOR A RED FLAG
WARNING. FOR MORE INFO... SEE THE FIRE WEATHER SECTION BELOW.

77/GLEASON

&&

.AVIATION...
18Z TAF DISCUSSION.

EXPECT VFR CONDITIONS TO PREVAIL THROUGH THIS TAF PERIOD. WINDS
WILL GENERALLY BE FROM THE NORTHWEST AS HIGH PRESSURE CENTERED
OVER MISSISSIPPI MOVES SLOWLY EAST TONIGHT. SOME GUSTS WILL BE
POSSIBLE THIS AFTERNOON ACROSS EASTERN AND CENTRAL TAF SITES WITH
A SLIGHTLY ENHANCED PRESSURE GRADIENT. WINDS SHOULD CALM AFTER 00Z
TONIGHT.

77/GLEASON

&&

.FIRE WEATHER...

A DRY AND COOL AIR MASS WILL REMAIN IN PLACE ACROSS CENTRAL
ALABAMA TODAY UNDER A RIDGE OF HIGH PRESSURE. RELATIVE HUMIDITY
VALUES WILL DROP TO AROUND 25 PERCENT THIS AFTERNOON ACROSS THE
SRN PORTIONS OF THE AREA FOR A FEW HOURS. HAVE REMOVED THE NRN
HALF OF C AL OUT OF THE WATCH AS THEY DO NOT LOOK AS DRY. NOT
CONFIDENT THAT ANY OF THE AREA WILL HIT THE 4 HR TIME REQUIREMENT
SO WILL NOT UPGRADE THE WATCH TO A WARNING AT THIS TIME. A FIRE
WEATHER WATCH REMAINS IN EFFECT FOR THE SRN HALF OF C AL. MOISTURE
IS EXPECTED TO INCREASE AS WE PROGRESS THROUGH THE WEEK AS THE
SURFACE RIDGE WEAKENS AND DO NOT ANTICIPATE A NEED FOR ANY
ADDITIONAL WATCHES OR WARNINGS AFTER TODAY.

08/MK

&&

.PREV DISCUSSION... /ISSUED 502 AM CDT WED MAR 27 2013/

DISCUSSION...

SURFACE RIDGE THIS MORNING CURRENTLY SITUATED ALONG THE MS RIVER
VALLEY AND WITH A RIDGE CENTER ALONG THE SRN PORTION. WINDS ACROSS
C AL TONIGHT ARE MUCH LIGHTER OVERALL WITH LIGHT NRLY WINDS IN THE
EVENING THEN AFTER MIDNIGHT CONDITIONS HAVE CALMED ALONG WITH
WRAP AROUND MOISTURE RETREATING. THIS HAS ALLOWED SOME DECENT
RADIATIONAL COOLING TO OCCUR. CURRENT FREEZE WARNING IN GOOD SHAPE
AND WILL LEAVE IT UP FOR ALL OF C AL THROUGH 9 AM. 

ALTHOUGH STILL A COOL DAY IS EXPECTED AND SOME 10+ DEGREES BELOW
NORMAL...SUNNY SKIES WILL ALLOW FOR MORE WARM UP AS OPPOSED TO
YESTERDAY. ALSO...WINDS ARE NOT EXPECTED TO BE AS HIGH OR GUSTY
WITH MORE RELAXED PRESSURE GRADIENTS. SO WILL DEFINITELY FEEL MUCH
MILDER TODAY...FEELING CLOSER TO THE ACTUAL TEMPERATURES. NOW AS
WE MOVE INTO TONIGHT...LOOKING FOR A WEAK UPPER LEVEL SHORT WAVE
TO MOVE THROUGH THE NW FLOW WHICH IS NOT EXPECTED TO BRING RAIN
WITH RATHER DRY CONDITIONS...BUT WILL HELP TO GENERATE SOME
SHALLOW ENOUGH MOISTURE FOR SOME CLOUD COVER TO MOVE IN OVERNIGHT.
THIS ALONG WITH A SLIGHTLY WEAKER SURFACE RIDGE AS IT NUDGES A TAD
EWD TOWARD C AL...WILL ALLOW FOR SLIGHTLY LESS EFFICIENT COOLING
OVERNIGHT TONIGHT. AM NOT CONFIDENT ENOUGH TO UPGRADE OUR FREEZE
WATCH TO A WARNING JUST YET WITH WARMER TEMPERATURES THAN TONIGHT
EXPECTED ALONG WITH THE LATEST DATA FOR TONIGHT A TAD MILDER. WILL
LET THE FREEZE WATCH RIDE FOR NOW. 

THE WARM UP IS EXPECTED TO CONTINUE AS WE PROGRESS THROUGH THE
REMAINDER OF THE WEEK AS THE SURFACE RIDGE SLOWLY SHIFTS EWD WITH
THE FLOW BY FRI MORNING EXPECTED TO BE BRING WARM RETURN FLOW
MOISTURE BACK INTO THE AREA. WITH THE RETURN OF MOISTURE AND
WARMING TEMPERATURES...LOOKING FOR THE OPPORTUNITY FOR SHOWERS TO
RETURN BY FRIDAY AS WEAK WNW UPPER FLOW DISTURBANCE PASS THROUGH
THE REGION. THE BEST CHANCES WILL BE ACROSS THE NW HALF OF THE
STATE FOR FRI/SAT IN BETTER PROXIMITY TO THE SHORT WAVES AS THEY
MOVE ACROSS ALONG WITH THE BETTER MOISTURE.

BY EASTER SUNDAY...THE SURFACE RIDGE WILL CONTINUE TO SHIFT EWD
TO JUST OFF THE ATLANTIC COAST. UPPER FLOW BECOMES MORE ZONAL
ACROSS THE SE U.S. AS A RATHER LARGE UPPER LOW SETS UP OVER ERN
CANADA. LOOK FOR MORE AND STRONGER SHORTWAVES TO MOVE THROUGH THE
FLOW ON SUNDAY AS A FRONT ATTEMPTS TO PUSH INTO THE SE U.S.
HOWEVER...THE UPPER ZONAL FLOW WILL NOT AIDE THE SWD PROGRESSION
OF THIS FRONT AND IT IS EXPECTED TO STALL OR MOVE EXTREMELY SLOW
INTO THE NRN PART OF THE STATE BY MON MORNING. SO WE WILL BE
REMAINING IN THE WARMER SECTOR. NOT CONFIDENT ABOUT SEVERE
POTENTIAL FOR SUN WITH THE NEITHER THE SURFACE FRONT OR LOW
EXPECTED TO MOVE INTO THE AREA SUN. THINK THAT STORMS INTENSITY
WILL BE MORE DIURNALLY DRIVEN ASSOCIATED WITH THE SHORT WAVES.
0-6KM BULK SHEAR ALONG WITH HELICITY ARE WEAK. AL WILL BE
IN BETWEEN A SPLIT UPPER JET SETUP SO NO HELP THERE. FOR NOW WILL
LEAVE ANY SEVERE OUT FOR OUR NEXT FRONT.

RAIN CHANCES CONTINUE INTO MON AS FRONT IS EXPECTED TO STALL
SOMEWHERE ACROSS THE N TO MIDDLE PART OF C AL...WITH BEST RAIN
CHANCES S. THIS WILL KEEP US IN A SOMEWHAT WET PATTERN FOR THE
FIRST HALF OF THE WEEK. FAR EXTENDED MODELS DEVELOP A SECONDARY
SURFACE LOW TO MOVE ACROSS THE AREA IN THE FAR EXTENDED DURING THE
MIDDLE OF NEXT BUT CONFIDENCE REMAINS LOW ON THIS FEATURE AS THERE
IS A SPREAD IN THE DATA INCLUDING INTENSITY AND TIMING...BUT ALL
DATA CONTINUES TO POINT TO CONTINUED OPPORTUNITIES FOR RAIN SO
WILL KEEP RAIN CHANCES IN THE FORECAST THROUGH MID WEEK AND THE
END OF OUR FORECAST.

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR ALL OF
CENTRAL ALABAMA.

FIRE WEATHER WATCH UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING 
COUNTIES: AUTAUGA...BARBOUR...BIBB...BULLOCK...CHAMBERS...
CHILTON...COOSA...DALLAS...ELMORE...GREENE...HALE...LEE...
LOWNDES...MACON...MARENGO...MONTGOMERY...PERRY...PIKE...
RUSSELL...SUMTER...TALLAPOOSA.

&&

$$

77/08