FXUS64 KBMX 050552 AAC
AFDBMX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1152 PM CST SAT FEB 4 2012

.UPDATE...
FOR AVIATION.

&&

.AVIATION...
06Z TAF DISCUSSION.

PRE-FRONTAL TROUGH SHOWERS HAVE NOW MOVED ON TO GA...WITH MAINLY
LOW STRATUS/SOME FOG/AND STILL NOT RULING OUT DRIZZLE AHEAD OF THE
ACTUAL FRONT WHICH HAS STILL NOT YET ENTERED AL FROM MS. SHOULD
GET SOME RELIEF FROM POTENTIAL FOG AS FRONT MAKES ITS WAY INTO AL
OVER THE NEXT FEW HOURS. SO VSBY MAY NOT GO DOWN AS LOW
TCL/BHM/EET AS IT COULD OTHERWISE BEHIND THE RAIN. LOW STRATUS
SHOULD CLEAR OUT OF C AL BY MIDDAY AS THE FRONT PROGRESSES ACROSS
THE STATE AND HELPS TO DRY THE LOWER LEVELS OUT SOME.

08/MNK

&&

.PREV DISCUSSION... /ISSUED 935 PM CST SAT FEB 4 2012/

UPDATE...

FOR EVENING TRENDS.

DISCUSSION...

RAINFALL CONTINUES TO LINGER OVER THE SOUTHEASTERN CORNER OF THE
CWA AHEAD OF A SLOW MOVING COLD FRONT THAT WILL PUSH THROUGH THE
STATE BY SUNRISE. LITTLE IN THE WAY OF COLD ADVECTION BEHIND THE
FRONT AS OVERNIGHT TEMPERATURES WILL GENERALLY REMAIN IN THE 50S.
WILL KEEP A WATCH ON RADAR TRENDS AND ADJUST POPS AS NEEDED.
OTHERWISE...NO SIGNIFICANT CHANGES.

88

PREV DISCUSSION... /ISSUED 342 PM CST SAT FEB 4 2012/

DISCUSSION...

RATHER ACTIVE PATTERN ACROSS THE CONUS AND NORTH AMERICA THROUGH
THE WEEK...BUT FOR NOW IT APPEARS THAT CENTRAL ALABAMA WILL NOT BE
VERY INVOLVED WITH ALL THE FESTIVITIES. SUBTROPICAL JET TO THE
SOUTH...POLAR AND ARCTIC JETS TO THE NORTH...AND PREDOMINANTLY
ZONAL FLOW ACROSS THE AREA WILL KEEP US IN SEASONABLE AIR MASSES
BETWEEN AND SIGNIFICANT SENSIBLE WEATHER. THE ONLY CAVEAT IS...IF
THE PATTERN DEVIATES 500 MILES NORTH OR SOUTH...THE FORECAST AS IT
STANDS NOW WOULD BE IN JEOPARDY. ONCE THIS FRONT PASSES THROUGH
TONIGHT INTO TOMORROW...THE FORECAST IS ESSENTIALLY RAIN FREE IN
SPITE OF SEVERAL FRONTS PASSING THROUGH THE AREA DURING THE WEEK.

SHORT TERM...TONIGHT AND TOMORROW.

HEADACHES IN THE VERY SHORT TERM...TRYING TO GET A HANDLE ON THE
TIMING AND PLACEMENT OF THE WEAKENING PRE-FRONTAL SQUALL LINE THAT
CONTINUES TO EASE INTO THE FORECAST AREA. A FEW ISOLATED/SCATTERED
SHOWERS FORMING IN THE SURPRISINGLY WARM AIR IN THE CAPITOL
DISTRICT...AS ANTICIPATED BY MIDDAY HRRR RUNS. LATEST RUC AND HRRR
RUNS ALL HINT THE SQUALL LINE WILL BE A BIT OF A DIEING QUAIL AS
IT COMES INTO CENTRAL ALABAMA...AND RAPIDLY WEAKENS AS ALL MEANS
OF SUPPORT ARE LIFTING OUT. LOOKS LIKE WE WON'T GET THE DOUSING WE
WERE PREVIOUSLY ANTICIPATING...BUT DO EXPECT MOST LOCATIONS WEST
OF I-65 WILL SEE A HALF INCH TO AROUND AN INCH OF RAIN. AS THE
SYSTEM WEAKENS OVERNIGHT...RAINFALL AMOUNTS WILL TAPER OFF AS IT
HEADS TOWARDS THE GEORGIA LINE. BIG QUESTIONS REVOLVE AROUND
WHETHER OR NOT THE BACK EDGE OF THE RAIN WILL BE TO THE FAR
NORTHWEST CORNER OF THE FORECAST AREA BY 00Z...AND WHETHER OR NOT
RAINFALL WILL MAKE IT ALL THE WAY DOWN TO TROY AND EUFAULA BY 12Z.

LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.

ALL MODELS ARE IN SURPRISINGLY GOOD...TOO GOOD TO BE TRUE?...
AGREEMENT THROUGH THE WORK WEEK...THEN PART WAYS RAPIDLY BY NEXT
SATURDAY. CMC/GFS/ECMWF ALL AGREE THE BASIC SYNOPTIC PATTERN
CONTINUES TO EVOLVE INTO A DEEP LOW OVER HUDSON BAY AND TROUGHING
IN THE NORTHEAST...WITH AN EVENTUAL CLOSED LOW OVER BAJA AND
WESTERN MEXICO. THIS ALLOWS THE OLD CONTINENTAL FRONT SETTLING
OVER THE GULF TO PERSIST AS SOUTHERN STREAM FLOW OVER THE TOP
PROVIDES AN AMPLE SOURCE OF DYNAMICS...WHICH WILL MAKE IT TOUGH
FOR THE SUNSHINE STATE TO LIVE UP TO ITS NAME.

RELATIVELY HIGH HEIGHTS YET FRESHENING ZONAL FLOW OVER THE DEEP
SOUTH WILL HELP DRAG THE TAIL END OF NORTHERN STREAM SYSTEMS
THROUGH THE AREA...AS SHORTWAVES AROUND THE UPPER LOW PASS BY TO
OUR NORTH IN THE OHIO VALLEY. RIGHT NOW...AT LEAST TWO DISCERNIBLE
FRONTAL PASSAGES ON TAP. THE FIRST WILL BE A RATHER WEAK...DRY
FRONTAL PASSAGE TUESDAY/WEDNESDAY...WITH A SECOND MORE SIGNIFICANT
FRONTAL PASSAGE THURSDAY. THE SECOND FRONTAL SYSTEM HAS A BIT MORE
OOMPH BEHIND IT...COMING DOWN THE BACK SIDE OF THE DEEPENING
TROUGH...AND PERHAPS COMING INTO PHASE WITH OPENING/EJECTING
SOUTHERN STREAM LOW. STILL...THE SYSTEM IS CURRENTLY LOOKING TO BE
MOISTURE STARVED AND REALLY ONLY GIVES US A GLANCING BLOW OF WITH
SEASONABLY COOLER AIR.

NET RESULT THIS GO AROUND IS TO CONTINUE THE TREND OF DECREASING
POPS IN THE FORECAST...WITH ONLY MARGINAL POPS REALLY ACROSS THE
SOUTHERN PORTION OF THE FORECAST AREA THURSDAY/FRIDAY TO ACCOUNT
FOR A POSSIBLE NORTHWARD DRIFT OF THE SOUTHERN BRANCH...WHICH DOES
NOT LOOK TO BE THAT IMPRESSIVE OF A CHANCE AT THIS TIME. TEMPS
GENERALLY REMAIN AT OR ABOVE NORMAL THROUGH THE PERIOD.

02

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN 52 62 37 57 32 / 20 10 10 10 10
ANNISTON 56 66 39 59 35 / 20 10 10 10 10
BIRMINGHAM 55 61 39 57 37 / 20 10 10 10 10
TUSCALOOSA 54 63 36 60 36 / 20 10 10 10 10
CALERA 56 64 39 58 36 / 20 10 10 10 10
AUBURN 58 67 38 59 36 / 20 10 10 10 10
MONTGOMERY 59 69 41 62 38 / 20 10 10 10 10
TROY 60 70 42 61 35 / 20 10 10 10 10

&&

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

&&

$$

08/88/02



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