River Flood Warning 28, NWS Birmingham, AL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
620 AM CDT SUN MAY 5 2013

.UPDATE...
FOR 12Z AVIATION.

&&

.SHORT TERM...
TODAY THROUGH TUESDAY.

MOST OF CENTRAL ALABAMA IS CURRENTLY IN THE DRY SLOT...AS THE DEEP
COLD CORE LOW INCHES CLOSER FROM THE NORTHWEST. BECAUSE OF DEWPOINTS
REMAINING IN THE LOWER 40S FOR MOST LOCATIONS RECORD LOWS DON'T LOOK
LIKE THEY WILL BE IN JEOPARDY OF BEING BROKEN LIKE WE ORIGINALLY
THOUGHT. WITH CLEAR SKIES FOR SEVERAL LOCATIONS THIS MORNING IN
THE DRY SLOT...PATCHY DENSE FOG HAS BEEN ALLOWED TO DEVELOP WITH
PLENTY OF MOISTURE STILL AT THE SURFACE. WE HAVE GONE WITH A DENSE
FOG ADVISORY FOR AREAS ALONG AND EAST OF A LINE FROM ONEONTA...TO
BIRMINGHAM...TO CLANTON. THE VERY CHILLY TEMPERATURES ARE VERY
UNCHARACTERISTIC FOR THE 5TH OF MAY WITH THE NORMAL LOWS SUPPOSED
TO BE 56 AT BIRMINGHAM AND 57 FOR MONTGOMERY. IRONICALLY...WE ARE
FORECASTING HIGHS CLOSE TO THOSE VALUES THIS AFTERNOON AND ON
MONDAY AFTERNOON WITH THE COLD CORE LOW MEANDERING ALONG THE
INTERSTATE 20 CORRIDOR. RECORD LOW HIGH TEMPERATURES COULD BE
SHATTERED AT OUR CLIMATE LOCATIONS THROUGH MONDAY. SEE THE CLIMATE
SECTION BELOW FOR MORE INFORMATION ABOUT THE RECORD TEMPERATURES.

WE WILL START OUT THE DAY WITH THE PATCHY FOG CONTINUING ALONG AND
EAST OF INTERSTATE 65 WITH THE SUN EXPECTED TO MAKE AN APPEARANCE
AT LEAST THROUGH THIS MORNING. WITH MORE SUNSHINE IN THE EAST
TEMPERATURES SHOULD BE ABLE TO RISE INTO AT LEAST THE MID 60S.
AREAS IN THE NORTHWEST HOWEVER MIGHT NOT BE ABLE TO RISE OUT OF
THE MID 50S WITH THE CORE OF THE UPPER LOW MOVING OVERHEAD.
SHOWERS WILL BECOME WIDESPREAD TOWARD THE AFTERNOON HOURS AS
INSTABILITY VALUES ALOFT INCREASE. ALSO...AN UPPER LEVEL JET MAX
OF WELL OVER 100 KNOTS AT 300MB ROTATING AROUND THE SOUTHERN
PERIPHERY OF THE LOW WILL AID IN LIFTING THE SHOWERS AND POSSIBLE
STORMS...WITH CENTRAL ALABAMA LOCATED IN THE LEFT EXIT REGION.
ALTHOUGH I'VE GONE WITH DEFINITE POPS GENERALLY ALONG THE
INTERSTATE 20 CORRIDOR AND NORTHWARD...THE RAINFALL WILL BE
CONVECTIVE IN NATURE WITH BURSTS OF OCCASIONAL MODERATE DOWNPOURS
ESPECIALLY THIS AFTERNOON. A RUMBLE OF THUNDER WILL BE POSSIBLE
WITH SMALL HAIL NOT OUT OF THE QUESTION WITH ANY UPDRAFTS THAT CAN
PUNCH INTO THE -25 TO -27C TEMPERATURES AT 500MB.

GOING INTO THE OVERNIGHT PERIOD TONIGHT...THE SHOWERS WILL DECREASE
IN OVERALL COVERAGE BUT REMAIN WIDESPREAD NEAR THE CORE OF THE UPPER
LOW. THEREFORE...I'VE KEPT MENTION OF DEFINITE POPS FOR MAINLY OUR
NORTH AND NORTHEASTERN COUNTIES THROUGH THE NIGHT TONIGHT. LOWS
TONIGHT WITH THE WIDESPREAD CLOUDS AND SHOWERS WILL BE VERY COOL BUT
NOT TOO LOW IN THE UPPER 40S FOR MOST LOCATIONS.

FOR MONDAY WE ARE EXPECTING MORE OF THE SAME. SHORT RANGE GUIDANCE
IS DEPICTING THE LOW CENTERED ACROSS NORTHEASTERN ALABAMA BY EARLY
MONDAY MORNING. UPPER SUPPORT IS SLIM TO NONE FOR MOVING THE LOW ANY
FARTHER EAST BY THIS TIME AND IT COULD MEANDER IN AN ALMOST
STATIONARY FASHION THROUGH MONDAY AFTERNOON. WIDESPREAD CLOUDS AND
SHOWERS WILL ONCE AGAIN KEEP TEMPERATURES VERY COOL FOR MUCH OF CENTRAL
ALABAMA WITH WARMER TEMPS EXPECTED THE FURTHER SOUTH AND WEST YOU
GO. ONCE AGAIN I'VE THROWN OUT MOS GUIDANCE TEMPS AND WENT WITH A
BLEND OF RAW NAM/GFS/SREF GUIDANCE FOR HIGHS...WHICH WOULD BE IN
THE MID TO UPPER 50S EAST AND LOWER 60S ELSEWHERE.

AN UPPER LEVEL RIDGE FINALLY BEGINS TO BUILD ACROSS TEXAS BY TUESDAY
MORNING WHICH SHOULD BE ENOUGH TO MOVE THE UPPER LOW OFF TO OUR
EAST. CLOUDS SHOULD BE ON THE DECREASE DURING THE DAY ON TUESDAY
WITH PERHAPS A STRAY SHOWER OR TWO REMAINING POSSIBLE ACROSS OUR
EASTERN COUNTIES. 1000-850MB THICKNESSES LOOK TO SUPPORT AT LEAST
LOW TO MID 70S AREAWIDE WHICH WILL BE A VERY WELCOME WARM UP FROM
WHAT WE WILL EXPERIENCE THE NEXT FEW DAYS.

.LONG TERM...
WEDNESDAY THROUGH SATURDAY.

NEAR NORMAL TEMPERATURES FOR THIS TIME OF THE YEAR ARE FINALLY
EXPECTED THROUGH THE END OF THIS UPCOMING WEEK WITH UPPER LEVEL
HEIGHTS ON THE RISE ACROSS THE SOUTHEAST. PICTURE PERFECT WEATHER
LOOKS TO BE IN STORE FOR WEDNESDAY AND THURSDAY WITH LOWER 80S BEING
ADVERTISED FOR HIGHS. THE NEXT SYSTEM THEN LOOKS TO GET ITS ACT
TOGETHER OUT WEST WITH A CUT-OFF UPPER LOW ADVERTISED OVER THE FOUR
CORNERS REGION. LONG RANGE GUIDANCE IS STRUGGLING TO AGREE ON WHAT
TO DO WITH THIS SYSTEM...BUT THE OVERALL TRENDS ARE FOR MORE ACTIVE
WEATHER PATTERN WITH SOUTHWESTERLY FLOW ALOFT AND A DIGGING TROUGH
ACROSS THE EASTERN CONUS WHICH COULD MEAN A BETTER CHANCE OF MORE
ORGANIZED SHOWERS AND STORMS ACROSS THE SOUTHEAST BY NEXT WEEKEND.

56/GDG

&&

.AVIATION...
12Z TAF DISCUSSION.

QUITE AN INTERESTING MORNING TAF WISE OUT THERE. LOW CLOUDS ARE
IMPACTING ANB WITH LOW CLOUDS...PATCHY DENSE FOG DEVELOPED AHEAD
OF THE OUT BAND OF CLOUDS FROM THE UPPER LOW IMPACTING ASN. BHM
AND EET HAD PREVIOUSLY DROPPED BUT SINCE THAT OUTER BAND HAS NOW
CLEARED THE TWO THEY HAVE IMPROVED QUICKLY. AS THE LOW MOVES EAST
THE SITE WILL CLEAR BY 13 TO 14Z.

SCATTERED SHOWERS WILL BE POSSIBLE THIS MORNING ACROSS THE NORTH
AND THEN WIDESPREAD SHOWERS THIS AFTERNOON FOR THE NORTH. ACTIVITY
IN THE SOUTH WILL BE SCATTERED. THERE COULD BE A FEW RUMBLES OF
THUNDER ACROSS THE NORTH AFTER 20Z...BUT DID NOT INCLUDE IN TAFS
AS CHANCES ARE LOW. RAIN CHANCES REMAIN ACROSS THE NORTH REALLY
THROUGH THE REST OF THE CYCLE AS THE UPPER LOW SWINGS THROUGH.
MVFR CIGS AGAIN OVERNIGHT.

NOTE:THE SEASONAL TAF FOR TALLADEGA...KASN...IS NOW BEING
GENERATED BY NWS BMX. DUE TO COMMUNICATION LIMITATIONS...WILL
INCLUDE /AMD NOT SKED/ IN THE KASN TAF...AS AMENDMENTS WILL NOT BE
GUARANTEED. THIS TAF WILL BE AVAILABLE WITH AT LEAST 4 ROUTINE
DAILY SYNOPTIC UPDATES THROUGH MAY 9 AT 00Z.

16

&&

.CLIMATE...

AFTERNOON HIGH TEMPERATURES TODAY WILL BE AROUND 20 DEGREES BELOW
NORMAL. THIS COULD LEAD TO RECORDS BEING BROKEN FOR LOWEST DAILY MAXIMUM
TEMPERATURES FOR MANY LOCATIONS. HERE'S A LOOK AT THE CURRENT
LOWEST MAXIMUM TEMPERATURES FOR MAY 5TH AT OUR FOUR MAIN CLIMATE
LOCATIONS.

LOCATION            RECORD
-------------       ---------
BIRMINGHAM          60 (1917)
TUSCALOOSA          68 (1957,1960)
ANNISTON            62 (1931)
MONTGOMERY          59 (1874)

56

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR THE FOLLOWING
COUNTIES: CALHOUN...CHAMBERS...CHEROKEE...CLAY...CLEBURNE...
COOSA...ETOWAH...RANDOLPH...ST. CLAIR...TALLADEGA...TALLAPOOSA.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BIRMINGHAM AL
759 AM CDT SUN MAY 5 2013

ALZ011>015-017>050-061300-
MARION-LAMAR-FAYETTE-WINSTON-WALKER-BLOUNT-ETOWAH-CALHOUN-CHEROKEE-
CLEBURNE-PICKENS-TUSCALOOSA-JEFFERSON-SHELBY-ST. CLAIR-TALLADEGA-
CLAY-RANDOLPH-SUMTER-GREENE-HALE-PERRY-BIBB-CHILTON-COOSA-TALLAPOOSA-
CHAMBERS-MARENGO-DALLAS-AUTAUGA-LOWNDES-ELMORE-MONTGOMERY-MACON-
BULLOCK-LEE-RUSSELL-PIKE-BARBOUR-
759 AM CDT SUN MAY 5 2013

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

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT IS NOT
EXPECTED AT THIS TIME.