FXUS64 KBMX 222114
AFDBMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
314 PM CST TUE DEC 22 2009
.SHORT TERM...TODAY THROUGH THURSDAY.
A VERY ENJOYABLE DAY AROUND THE SOUTHEAST UNITED STATES TODAY AS
HIGH PRESSURE DOMINATES THE ATMOSPHERE. TEMPERATURES HAVE CREPT
INTO THE LOW 60S ACROSS OUR SOUTHERN COUNTIES AS EXPECTED...WITH
SOME CUMULUS DEVELOPMENT DUE TO A VERY WEAK INFLUX OF LOW LEVEL
MOISTURE. TEMPERATURES TONIGHT SHOULD CONTINUE THE MODERATION TREND
AS A LITTLE MORE MOISTURE IS EXPECTED INTO CENTRAL ALABAMA. A FEW
SPOTS MAY SEE MID 30S BUT MOST EVERYONE SHOULD BOTTOM OUT TONIGHT
AROUND 40.
LOOKING AT THE VISIBLE SATELLITE...WE'RE NOT ONLY SEEING THE
CUMULUS DEVELOPMENT BUT ALSO A THIN LAYER OF CIRRUS AHEAD OF OUR
NEXT WEATHER SYSTEM. THIS APPROACHING SYSTEM IS THE RESULT OF A
FAIRLY AMPLIFIED UPPER LEVEL TROUGH THAT DUG INTO THE SOUTHWEST
UNITED STATES LATE SUNDAY AND MONDAY...AND HAS PUSHED INTO THE
SOUTHERN PLAINS TODAY. THE RESULT OF THIS PUSH HAS BEEN THE BIRTH
OF THE SURFACE LOW THAT WILL AFFECT US OVER THE NEXT COUPLE OF
DAYS. CYCLOGENESIS WILL CONTINUE OVER THE NEXT 36 HOURS...AS THE
AXIS OF THE UPPER LEVEL TROUGH TILTS SLIGHTLY INTO THE NEGATIVE...
DEEPENING THIS SURFACE LOW TO 991MB BY THURSDAY EVENING. HERE'S
THE PROBLEM...EVEN THOUGH THIS CYCLOGENESIS IS HAPPENING...A VERY
STRONG RIDGE OF HIGH PRESSURE THAT RUNS THE LENGTH OF THE ATLANTIC
SEABOARD...STRENGTHENS OVER THIS TIMEFRAME...AND APPEARS TO HAVE
TWO MAJOR EFFECTS ACROSS OUR AREA. FIRST IT CREATES A VERY STRONG
WEDGE ALONG THE SOUTH SIDE OF THE APPALACHIAN MOUNTAINS. THIS
FAIRLY INTENSE WEDGE OF EASTERLY FLOW OVER CENTRAL ALABAMA IS
LIKELY GOING TO BE THE CULPRIT IN DENYING THE NORTHWARD INTRUSION
OF ANY SIGNIFICANT DEW POINTS INTO OUR AREA. SREF/GFS/EURO ARE ALL
IN VERY GOOD AGREEMENT ON TIMING AND STABILITY ACROSS THE REGION.
THE SECOND EFFECT OF THE HIGH PRESSURE RIDGE JUST TO OUR EAST IS
THAT THE SURFACE LOW IS GOING TO RUN INTO IT...AND NOT HAVE
ANYWHERE TO GO. THE RESULT IS GOING TO BE A VERY STRONG SURFACE
PRESSURE GRADIENT OVER ALABAMA AND MISSISSIPPI BEGINNING WEDNESDAY
NIGHT. MODELS HAVE BEEN VERY CONSISTENT WITH THIS FEATURE AND THE
RESULT IS GOING TO BE STRONG WINDS ACROSS CENTRAL ALABAMA FOR MOST
OF THE DAY THURSDAY. SUSTAINED WINDS OF 20 TO 25 MPH...WITH GUSTS
PROBABLY AS HIGH AS 35 OR 40 MPH WILL LIKELY BE COMMONPLACE
THROUGHOUT THE DAY. THESE WINDS WILL LIKELY BE THE MAIN PROBLEM
CHILD ON THURSDAY AS INSTABILITIES LOOK TO BE LOW AND QPF LOOKS TO
BE IN THE NEIGHBORHOOD OF 1 TO 3 INCHES OVER A 6 TO 8 HOUR TIME
FRAME. NOW...I WILL NOT COMPLETELY RULE OUT A COUPLE OF ISOLATED
STRONG STORMS AS WE COULD SEE AN APPROACHING LINE OF CONVECTION...
GIVING US THE POTENTIAL OF SOME STRAIGHT LINE WINDS THURSDAY
AFTERNOON...BUT THIS WINDOW IS EXPECTED TO BE VERY SMALL. THE BEST
CHANCES THURSDAY AFTERNOON INTO THE EARLY EVENING HOURS...WHEN LOW
60 DEGREE DEW POINTS ARE ABLE TO GET INTO OUR SOUTHWESTERN COUNTIES
FOR A VERY SHORT PERIOD OF TIME. WITH A VERY HIGHLY SHEARED...LOW
TO NO ZERO CAPE ENVIRONMENT ...THERE WILL BE AN OUTSIDE CHANCE TO
REALIZE THE 50-60KT LLJ AT THE SURFACE. FOR THIS REASON...WILL
KEEP THE MENTION OF STRONG STRONG STORMS IN THE HWO FOR THURSDAY
ALONG WITH THE PRESSURE GRADIENT WINDS.
.LONG TERM...CHRISTMAS DAY THROUGH TUESDAY.
AFTER ALL OF THAT...MOISTURE LOOKS TO MOVE OUT OF THE STATE QUICKLY
CHRISTMAS MORNING. I WOULD NOT BE SURPRISED TO SEE SOME BREAKS OF
SUN FRIDAY AFTERNOON...BUT I DON'T REALLY EXPECT THIS TO LAST
THROUGH THE WEEKEND. ALTHOUGH IT SHOULD BE DRY OVER THE WEEKEND AND
SOME SUN MAY BE SEEN ON SATURDAY...THE UPPER LEVEL TROUGH FROM
THURSDAY LOOKS TO MEANDER OVER THE EASTERN HALF OF THE COUNTRY
THROUGHOUT THE WEEKEND WHICH WILL PROVIDE US WITH A SOUTHWESTERLY
FLOW OVER THE STATE...LIKELY GIVING US CLOUDS FOR MOST OF THE
WEEKEND AND INTO THE DAY ON MONDAY.
LONG RANGE MODELS SHOW THE DEVELOPMENT OF ANOTHER GULF LOW IN THE
LATE MONDAY TO TUESDAY TIMEFRAME...BUT WILL WAIT FOR SOME CONTINUITY
BEFORE CHASING UPPER END CHANCE MOS GUIDANCE POPS IN DAY 8.
MOS GUIDANCE IS ALSO SHOWING SLIGHT TO CHANCE POPS THROUGH THE
WEEKEND BUT I BELIEVE THIS IS DUE TO CLIMO AND WILL TAKE FULL
ADVANTAGE OF BEATING MOS IN THIS TIME FRAME.
NO REAL CONCERNS TEMPERATURE-WISE AS WE WILL BE CLOSE TO CLIMO NORMS
FOR THIS TIME OF YEAR. COLDEST MORNING SHOULD BE SUNDAY AND MONDAY
AS THE NORTHERN HALF OF THE CWA DROPS INTO THE MIDDLE 20S.
27
&&
.AVIATION...18Z TAF DISCUSSION.
VFR CONDS EXPECTED THRU THE PERIOD WITH LIGHT SOUTHERLY WINDS
THROUGH THE PERIOD. HIGH CLOUDS WILL BEGIN TO BUILD IN AFTER 00Z AS
THE NEXT SYSTEM APPROACHES THE AREA. MAY SEE SOME DECKS AROUND 5000
FEET FOR THE NORTHERN TAF SITES BY 15Z ON WEDNESDAY AS WELL.
16
&&
.PRELIMINARY POINT TEMPS/POPS...
GADSDEN 36 58 40 56 47 / 10 20 30 90 100
ANNISTON 35 59 44 56 49 / 10 10 20 90 100
BIRMINGHAM 42 58 47 56 49 / 10 20 30 100 100
TUSCALOOSA 41 60 50 61 48 / 10 30 40 100 90
CALERA 39 59 46 59 49 / 10 20 30 100 100
AUBURN 37 60 43 56 49 / 0 10 20 90 100
MONTGOMERY 39 63 47 63 51 / 10 10 20 100 100
TROY 36 63 45 63 50 / 10 10 20 90 100
&&
.BMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
27/16
