FXUS64 KBMX 062134
AFDBMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
334 PM CST SUN DEC 6 2009
.DISCUSSION...
WOW. FAST MOVING SYSTEMS AND ACTIVE WEATHER PATTERN ALL MAKE FOR A
RATHER CHALLENGING FORECAST OVER THE NEXT 7 DAYS. THERE ARE TWO
MAIN SYSTEMS OF CONCERN DURING THAT TIME...ONE THAT COULD BRING US
SOME SEVERE WEATHER LATE TUESDAY INTO EARLY WEDNESDAY...AND THE
OTHER THAT WILL BRING MORE RAIN...AND A POSSIBLE CAD WEDGE WITH
TEMPERATURES PERILOUSLY CLOSE TO FREEZING FOR A TIME TOWARD THE
END OF THE WEEK.
CURRENTLY...CONDITIONS REMAIN RATHER CHILLY WITH THICK CLOUDS
GATHERING TO THE WEST. WEAK SHORTWAVE PASSING THROUGH TONIGHT AND
MONDAY WILL BRING INCREASING CHANCES OF RAIN. ALTHOUGH POPS WILL
BE IN THE LIKELY CATEGORY FOR MUCH OF THE AREA ON MONDAY...THE
RAIN WON'T BE AROUND FOR ALL THAT LONG...NOR WILL AMOUNTS BE ALL
THAT MUCH. THERE'S A BIT OF A LULL IN THE PRECIP MONDAY
EVENING...BEFORE THE NEXT SYSTEM REALLY GETS CRANKED UP ON TUESDAY.
ALTHOUGH THE BULK OF THE UPPER LEVEL ENERGY ASSOCIATED WITH THE
TUESDAY/WEDNESDAY SYSTEM IS FORECAST TO PASS JUST TO OUR
NORTH...THE AMOUNT OF LOW LEVEL FORCING AND OTHER FACTORS ALL
POINT TO TUESDAY BEING A RATHER RAIN FILLED DAY. AS SUCH...THERE
IS REALLY NOT MUCH OPPORTUNITY TO DESTABILIZE...AND I GET THE
FEELING THAT THERE WON'T BE MUCH (IF ANY) THUNDER AROUND DURING
THIS PHASE OF THIS SYSTEM.
HOWEVER...OVERNIGHT TUESDAY NIGHT THE LOW LEVEL JET REALLY GETS
CRANKED UP AS THE SURFACE CYCLONE INTENSIFIES AND MOVES TOWARDS
THE GREAT LAKES. MODEL SOUNDINGS SHOW THE "GREATEST" AMOUNT OF
CAPE OCCURRING DURING THE OVERNIGHT HOURS. BUT THAT IS STILL A
MODEST 400-800 AT MOST. BUT WITH SHEAR VALUES THROUGH THE ROOF...
ANY SURFACE BASED UPDRAFTS THAT CAN BECOME SUSTAINED WILL BE PRONE
TO START ROTATING. THUS...WE WILL CONTINUE TO MENTION THE
POSSIBILITY OF SEVERE STORMS (INCLUDING THE THREAT OF TORNADOES) IN
THE HAZARDOUS WEATHER OUTLOOK. ALSO...I AM STILL A BIT LEARY OF
THE POSSIBILITY OF EVERYTHING BEING DELAYED MORE INTO WEDNESDAY...
WHICH WOULD GIVE THE LOW LEVELS A BIT MORE OPPORTUNITY TO DESTABILIZE.
BY LATE WEDNESDAY AFTERNOON...WE SHOULD BE EXPERIENCING RATHER
STRONG COLD ADVECTION IN THE WAKE OF THE COLD FRONTAL PASSAGE.
THURSDAY IS AN IN BETWEEN DAY...WITH THE NEXT SYSTEM SLATED TO
COME IN HERE FRIDAY INTO SATURDAY. THIS SYSTEM IS A BIT MORE
SUBTLE IN ITS FEATURES...AND INVOLVES A WEAKER SOUTHERN STREAM
SHORTWAVE. ONE THING OF DISCONCERTING NOTE IS THE WAY THE EUROPEAN
MODEL BUILDS HIGH PRESSURE ALONG THE EAST COAST...WHILE THE NEXT
OVERRUNNING BATCH OF RAIN BREAKS OUT FRIDAY NIGHT INTO SATURDAY
MORNING. THIS SETS UP WHAT COULD BECOME QUITE A STRONG IN SITU
TYPE CAD WEDGE...WHICH DURING THE (METEOROLOGICAL) WINTER MONTHS
ALWAYS NEEDS TO BE WATCHED. I WAS A LITTLE THROWN BACK BY THE
CATEGORICAL POPS THE GFS MOS SPIT OUT FRIDAY NIGHT. BUT THIS WAS
WELL SUPPORTED BY THE 12Z ECMWF...SO I PUT MY CHIPS ALL IN WITH
THAT WET SOLUTION. THERE'S INCREASINGLY WARM AIR IN THE 850 MB
RANGE...AND SURFACE TEMPS ARE FORECAST TO ALSO STAY ABOVE
FREEZING. SO...A COLD RAIN IS FORECAST.
/61/
&&
.AVIATION...18Z TAF DISCUSSION.
MAINLY A CLOUD FORECAST OVER THE NEXT 24 HOURS. HIGH CLOUDS
STREAMING ACROSS THE AREA WILL CONTINUE THROUGH MUCH OF THE PERIOD
AS A STORM SYSTEM TO THE WEST STRENGTHENS. EXPECT CLOUD HEIGHTS TO
BEGIN LOWERING TONIGHT...AND DOWN TO 5KFT TOMORROW MORNING. CLOUD
HEIGHTS ARE EXPECTED TO LOWER TO MVFR IN TCL BY MID MORNING WITH
RAIN SHOWERS IN THE AREA. THINK MOST OF THE ACTIVITY WILL REMAIN
WEST OF THE TERMINALS UNTIL AFTER 18Z. THROUGH THE FORECAST
PERIOD...WINDS WILL MAINTAIN AN EASTERLY COMPONENT.
LIGHT RAIN SHOWERS ARE EXPECTED TO CROSS CENTRAL ALABAMA
TOMORROW...MAINLY DURING THE AFTERNOON AND EARLY EVENING HOURS...AS
A WEAK FRONT MOVES ACROSS THE AREA.
14
&&
.PRELIMINARY POINT TEMPS/POPS...
GADSDEN 32 50 39 55 53 / 0 60 30 100 100
ANNISTON 32 53 41 56 54 / 0 50 30 100 100
BIRMINGHAM 36 54 46 59 56 / 10 60 30 100 100
TUSCALOOSA 38 51 47 63 57 / 20 70 50 100 100
CALERA 36 55 46 58 57 / 10 60 30 100 100
AUBURN 37 60 45 57 54 / 0 30 10 90 70
MONTGOMERY 37 60 48 62 60 / 0 40 20 90 70
TROY 37 60 47 63 58 / 0 30 10 80 60
&&
.BMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
