000
FXUS64 KBMX 152334
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
634 PM CDT MON MAR 15 2010

.UPDATE...AVIATION DISCUSSION.

.DISCUSSION...

THE CLOUDS CONTINUE TO HANG ON THIS AFTERNOON AS EXPECTED...WHICH IS
CAUSING TEMPERATURES TO REMAIN 5-10 DEGREES BELOW CLIMATOLOGICAL
NORMS FOR THIS TIME OF YEAR.  COUPLED WITH THE BREEZY CONDITIONS...
IT COULD BE A FALL DAY OUT THERE.  NONETHELESS...SPRING IS JUST
AROUND THE CORNER...AS WERE SEEING IN THE MODELS QUITE PREVALENTLY
BY THE FORECAST UNCERTAINTY.  WELL GET THERE.

FOR NOW...THE COLD AIR ADVECTION ON THE BACK SIDE OF THE UPPER LEVEL
LOW WILL PERSIST AS NWLY UPPER LEVEL FLOW HOLDS STRONG OVER THE
SOUTHEAST.  THIS SHOULD BEGIN TO RELAX TUESDAY AS THE NEXT
TROUGH...WHICH IS CURRENTLY OUT OVER THE FOUR CORNERS REGION...
BEGINS TO SLIDE INTO THE SOUTHEAST.  MODELS ARE IN FAIRLY GOOD
AGREEMENT ABOUT THE TIMING OF THIS NEXT SYSTEM...AS WELL AS THE FACT
THAT THERE IS NOT EXPECTED TO BE MUCH IF ANY INSTABILITY ACCOMPANYING
IT. THE BIGGEST DISPARITY BETWEEN THE MODELS CONTINUES TO BE THE
AMOUNT OF QPF THAT WILL COME OUT OF THIS SYSTEM. GFS/GEM CONTINUE
TO BE FAIRLY DRY...AND THE EURO KEEPS ITS ELEVATED MOISTURE LEVELS
WITH THIS LATEST RUN. THE NAM IS THE IN-BETWEEN...SO WILL RUN WITH
THE TOTALS FROM THE 12Z NAM. THIS MEANS LIGHT RAINFALL TOTALS
THROUGH THURSDAY...WITH EVERYONE STAYING BELOW 0.50 INCHES. THATS
GOOD NEWS AS WET AS THE GROUND IS RIGHT NOW.

RIDGING SETTLES BACK INTO THE SOUTHEAST ON FRIDAY WHICH WILL
MODERATE TEMPERATURES BACK INTO THE MIDDLE TO UPPER 60S AND LOW 70S
BY SATURDAY AFTERNOON.

NOW FOR THE UNCERTAINTY IN THE FORECAST.  SATURDAY NIGHT...MODELS
ARE IN VERY GOOD AGREEMENT THAT ITS GOING TO RAIN IN SOME FASHION.
ALL HAVE A FRONTAL SYSTEM APPROACHING THE AREA...BUT CAUSED BY A
DIFFERENT UPPER LEVEL PATTERN WITH EACH MODEL.  HERES THE
DIFFERENCES AT THIS POINT...THE GFS KEEPS THE LOW LEVEL RETURN FLOW
ON THE WEAK SIDE.  THIS LIMITS INSTABILITY AS THE FRONT MOVES
THROUGH THE AREA.  THE GEM SEEMS TO BE THE MOST AGGRESSIVE WITH THE
SURFACE LOW AND CYCLOGENESIS AS A 990MB LOW ACCOMPANIES THE FRONT
SATURDAY NIGHT.  PLENTY OF SURFACE INSTABILITY IS ASSOCIATED WITH
THE FRONT AS WELL.  THE EURO SEEMS TO BE LYING IN THE MIDDLE RIGHT
NOW...SO WILL RUN WITH IT IN THE LONG TERM.  THIS MEANS A GOOD SHOT
OF THUNDERSTORMS SATURDAY NIGHT...SO WILL RUN ABOVE MOS POPS FOR
THIS PERIOD.  IN REGARDS TO THE HWO...WITH THE UNCERTAINTY IN THE
LONG TERM...WILL LIKELY WAIT UNTIL TONIGHTS PACKAGE TO TRY AND SEE
SOME CONTINUITY BEFORE INTRODUCING THUNDERSTORMS.

27

.AVIATION...00Z TAF DISCUSSION.

CLOUDS WILL CONTINUE TO BE THE FOCUS FOR THIS TAF PERIOD. NORTH TO
NORTHWESTERLY WINDS WILL DIMINISH THIS EVENING...REMAINING AT 4-5
KTS OVERNIGHT. AFTER MIDNIGHT...EXPECT THE CLOUD DECK TO BOUNCE
BETWEEN HIGH END MVFR TO LOW END VFR CEILINGS THROUGH TUESDAY
MORNING. HAVE BROUGHT CEILINGS UP TO VFR AFTER 15Z.

DESPITE AN UPPER LEVEL SHORT WAVE APPROACHING THE AREA LATE TUESDAY
FROM THE SOUTHERN PLAINS...LOW AND MID LEVEL FLOW REMAINS THE SAME
ACROSS CENTRAL ALABAMA...OUT OF THE NORTH TO NORTHWEST. LOW LEVEL
MOISTURE VALUES WARRANT MAINTAINING A LOW END VFR CEILING THROUGH
TUESDAY AFTERNOON.

14

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     37  56  44  56  41 /   0   0  10  30  20
ANNISTON    38  59  44  55  44 /   0   0  10  30  30
BIRMINGHAM  39  58  43  57  44 /   0   0   0  30  20
TUSCALOOSA  40  60  44  60  41 /   0   0   0  30  20
CALERA      40  59  45  56  45 /   0   0   0  30  20
AUBURN      38  62  43  56  44 /   0   0   0  30  30
MONTGOMERY  40  65  44  60  45 /   0   0   0  30  20
TROY        38  66  41  59  40 /   0   0   0  30  20

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

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