FXUS64 KBMX 060920
AFDBMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
320 AM CST SUN DEC 6 2009
.DISCUSSION...
WELL...WITH THE SNOW/SNOW FORECAST IN THE REAR-VIEW MIRROR...MY
ATTENTION WILL FOCUS ON THE ACTIVE WEATHER PATTERN THAT LAY AHEAD
FOR THE COMING WORK WEEK. WE WILL HAVE SEVERAL OPPORTUNITIES FOR
RAIN OVER THE NEXT 7 DAYS...INCLUDING THE THREAT FOR SEVERE
WEATHER TUESDAY AND WEDNESDAY.
LOOKING AHEAD TO THE HIGH IMPACT DAYS TUESDAY AND WEDNESDAY...A
SUBSTANTIAL MID LEVEL OPEN WAVE WILL WORK OUT OF THE CENTRAL
PACIFIC ALONG A SCREAMING SOUTHERLY JET AXIS LATE MONDAY THROUGH
EARLY TUESDAY. THIS TROF AXIS WILL QUICKLY TURN TO A MORE NEGATIVE
TILT TUESDAY AND THE RESULTANT SURFACE LOW WILL DEEPEN RATHER
QUICKLY AS IT EJECTS FROM THE TX/OK PANHANDLE ACROSS THE CENTRAL
PLAINS AND MID MISSISSIPPI VALLEY REGION. THE SURFACE LOW AND
RELATED WARM FRONTAL BOUNDARY WILL BEGIN TO LIFT RAPIDLY NORTHWARD FROM
THE GULF COAST BEHIND A STRONG SOUTH-SOUTHEASTERLY FLOW ON TUESDAY
AFTERNOON. THIS WILL BEGIN TO SCOUR OUT THE STRONG WEDGED AIRMASS
THAT WILL HAVE A DEEP HOLD ACROSS CENTRAL ALABAMA. WINDS IN THE
PROGGED WARM SECTOR WILL QUICKLY TURN FROM NORTHEAST TO SOUTHEAST
AND EVENTUALLY SOUTH AS THE WARM FRONT LIFTS NORTH BRINGING
SUBSTANTIAL GULF MOISTURE ACROSS MUCH OF THE AREA. THIS WILL BE AN
IMPORTANT DETAIL IN WHERE SEVERE WEATHER WILL DEVELOP...INITIALLY
ACROSS THE STATE LINE IN MS AND WORKING FURTHER EAST DURING THE LATE
AFTERNOON HOURS ON TUESDAY. THE FORECAST CHALLENGE WILL THEN BE ON
AS TO HOW MUCH INSTABILITY CAN BE REALIZED LATE TUESDAY SOUTH OF
THE LIFTING WARM FRONT. THE DEWPOINT AND TEMP TRENDS WILL NEED TO
BE MONITORED CAREFULLY TO SEE IF THEY CAN OVERCOME WHAT WILL BE A
DECENT CAPPING INVERSION LEFT BY THE INFLUENCE OF THE WEDGE.
INDICATIONS ARE AT THIS POINT...THAT AT LEAST THE SOUTHERN HALF TO
SOUTHERN TWO THIRDS OF THE CWA CAN REACH MID 60S DEWPOINTS BY LATE
TUESDAY. IF SO...THIS WILL PROVIDE A RIPE ENVIRONMENT FOR
SUPERCELL DEVELOPMENT...AND WITH THE DIFFLUENCE ALOFT...SOME OF
THESE SUPERCELLS COULD BE RATHER LONG-LIVED ALONG AND SOUTH OF THE
BOUNDARY. A BROKEN...SHEARED SQUALL LINE WILL LIKELY FOLLOW AS THE
COLD FRONT CONTINUES TO STRENGTHEN TO OUR WEST AND MOVE ACROSS THE
CWA BY EARLY WEDNESDAY. WILL HAVE TO SEE HOW MUCH INFLUENCE THE
DIURNAL CHANGE WILL MAKE ON THE ENVIRONMENT AS DAY TURNS TO NIGHT
ON TUESDAY...WHICH ONLY ADDS MORE QUESTIONS TO THE FORECAST. MAKE NO
MISTAKE ABOUT IT...THE SHEAR PROFILES WILL BE PRODUCTIVE TO
SUPERCELLS...AND ALL THREE THREATS...TORNADOES...DAMAGING WINDS
AND HAIL WILL BE IN THE CARDS WITH THIS EVENT. IF...AND ONLY
IF...THE WARM SECTOR CAN MOISTEN FAST ENOUGH LATE TUESDAY. WITH
THESE THREATS IN MIND...WILL BE ADDING THE RISK FOR TORNADOES TO
THE HWO FOR TUESDAY LATE AFTERNOON THROUGH AT LEAST A PORTION OF
THE OVERNIGHT PERIOD. WE WILL BE MONITORING THE SIGNIFICANT DETAIL
OF INSTABILITY THROUGHOUT SUBSEQUENT FORECAST PACKAGES...AS IT
WILL PROVE TO MAKE OR BREAK THIS EVENT.
17/KLAWS
&&
.AVIATION...06Z TAF DISCUSSION.
A THIN LAYER OF HIGH CIRRUS CLOUDS CONTINUE TO MOVE IN FROM THE WEST
THIS EVENING. THEY ARE EXPECTED TO INCREASE IN COVERAGE THROUGH OUT
THE DAY TOMORROW. OTHERWISE...NO AVIATION CONCERNS ARE EXPECTED AT
THIS TIME.
10/ARM
&&
.PRELIMINARY POINT TEMPS/POPS...
GADSDEN 50 33 51 41 58 / 0 10 50 20 70
ANNISTON 52 35 53 45 62 / 0 10 50 20 70
BIRMINGHAM 53 39 54 47 61 / 0 10 60 20 70
TUSCALOOSA 51 40 53 47 63 / 0 20 60 20 80
CALERA 55 37 53 48 62 / 0 10 60 20 80
AUBURN 52 39 56 47 60 / 0 10 30 20 70
MONTGOMERY 53 42 60 52 65 / 0 10 40 20 70
TROY 55 37 61 47 65 / 0 10 30 20 70
&&
.BMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
17/10
