FXUS64 KBMX 221037
AFDBMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
437 AM CST TUE DEC 22 2009
.DISCUSSION...
HIGH PRESSURE WILL PUSH EAST OF THE AREA TODAY...AS WINDS INCREASE
FROM THE SOUTH. HIGH TEMPS WILL BE SEVERAL DEGREES WARMER THIS
AFTERNOON UNDER SUNNY SKIES...AS THE AIRMASS ACROSS THE AREA CONTINUES
TO MODERATE. OVERNIGHT LOWS WILL BE IN THE MID 30S IN THE EAST AND
LOW 40S ELSEWHERE.
UPPER TROUGH WILL DROP INTO THE DESERT SOUTHWEST TONIGHT AND MOVE
INTO THE SOUTHERN PLAINS TOMORROW. SFC LOW WILL DEEPEN AND MOVE UP
THE MISSISSIPPI RIVER VALLEY THURSDAY...BRINGING A COLD FRONT/SQUALL
LINE INTO CENTRAL ALABAMA THURSDAY NIGHT. SURFACE HIGH PRESSURE
BECOMES ANCHORED NORTH OF THE GREAT LAKES IN SOUTHERN CANADA BY
TOMORROW...CREATING A WEDGE SET UP DOWN THE EAST SIDE OF THE
APPALACHIANS AND INTO EAST CENTRAL ALABAMA.
OVERALL THINKING HAS NOT CHANGED WITH THIS FORECAST PACKAGE. MODELS
CONTINUE TO BE IN GOOD AGREEMENT WITH THE PROGRESSION AND TIMING OF
THIS SYSTEM. HAVE BACKED OFF POPS FOR WEDNESDAY AS TIMING IS
BECOMING MORE REFINED...AND WOULD NOT BE SURPRISED IF MOST OF THE
ACTIVITY REMAINS WEST OF THE AREA UNTIL WEDNESDAY EVENING. WEDGING
AROUND THE SOUTHERN APPALACHIANS WILL MAINTAIN AN EASTERLY SURFACE
WIND AND COOL/DRIER AIRFLOW INTO THE NORTHEAST PORTION OF THE
FORECAST AREA. WARM FRONT LIFTING NORTHWARD AHEAD OF THIS SYSTEM
WILL HAVE A HARD TIME ERODING THIS WEDGE...LIMITING SURFACE INSTABILITY.
BEST AIRMASS FOR SEVERE STORMS WILL REMAIN TO THE SOUTH...NEAR THE GULF
COAST. HOWEVER...WITH A STRONG LLJ /70KT+/ CROSSING THE
AREA...CANT RULE OUT A DAMAGING WIND THREAT ALONG THE SQUALL LINE.
IN ADDITION...A TIGHTENING PRESSURE GRADIENT AHEAD OF THIS SYSTEM
WILL CREATE WINDY CONDITIONS BEGINNING THURSDAY MORNING...PEAKING
JUST AHEAD OF THE FRONT OVERNIGHT THURSDAY.
FRONT WILL PUSH EAST OF THE AREA BY FRIDAY MORNING...WITH RAIN
ENDING FROM WEST TO EAST ACROSS CENTRAL ALABAMA AFTER MIDNIGHT. WILL
INCLUDE LIGHT RAIN ACROSS THE NORTHERN PORTION OF THE AREA FRIDAY
MORNING BEHIND THE FRONT. WILL KEEP CHANCES LOW...AS MOISTURE
LIFTS AWAY FROM THE AREA QUICKLY. SYSTEM BECOMES STACKED AND
MEANDERS AROUND THE MIDWEST FOR SEVERAL DAYS...BEFORE EJECTING TO
THE NORTHEAST EARLY NEXT WEEK. THIS WILL SEND WEAK UPPER LEVEL
ENERGY/CLOUD COVER ACROSS THE AREA OVER THE WEEKEND. IN
ADDITION....LOW/MID LEVEL FLOW WILL BE FROM THE WEST RATHER THAN
NORTH...HINDERING CAA INTO THE AREA. AS A RESULT...WILL BUMP
TEMPERATURES UP FOR FRIDAY. HIGHS WILL BE IN THE 50S AND LOWS IN
THE UPPER 20S AND 30S. CAA INCREASES SAT/SUN AND WILL KEEP HIGHS
IN THE 40S AND LOW 50S EACH AFTERNOON. OVERNIGHT TEMPS WILL BE IN
THE MID 20S TO LOW 30S.
14
&&
AVIATION...06Z TAF DISCUSSION.
STILL LOOKING AT THE POTENTIAL FOR FOG THE REST OF THE NIGHT.
EARLIER TONIGHT...IT LOOKED LIKE THE SAME STATIONS THAT SAW FOG LAST
NIGHT WERE GOING TO SEE THE SAME CONDITIONS AGAIN TONIGHT.
HOWEVER...HIGH CLOUDS COMING IN FROM THE WEST COULD HELP PREVENT FOG
FROM FORMING AT ALL. BASED ON OBSERVATIONS SITES ACROSS
MISSISSIPPI...TEMPERATURES SHOT UP 5 DEGREES OR MORE WHEN THESE
CLOUDS MOVE THROUGH. THIS WILL HELP KEEP THE SPREAD BETWEEN
TEMPERATURE AND DEWPOINT FAR AWAY ENOUGH TO HELP PREVENT FOG FROM
DEVELOPING. FOR NOW...KEPT MVFR CONDITIONS ACROSS THE SAME LOCATIONS
THAT SAW FOG LAST NIGHT. HOWEVER...WHETHER OR NOT THEY WILL DROP
BELOW THAT IS STILL IN QUESTION. LEFT AT LEAST BCFG IN THE FORECAST
TO REFLECT THE POSSIBILITY OF SHALLOW DENSE FOG.
CONDITIONS ARE EXPECTED TO IMPROVE QUICKLY SHORTLY AFTER 13Z.
10/ARM
&&
.PRELIMINARY POINT TEMPS/POPS...
GADSDEN 57 37 58 40 55 / 0 0 20 30 70
ANNISTON 58 36 59 44 55 / 0 0 10 20 70
BIRMINGHAM 61 43 58 47 59 / 0 0 20 30 80
TUSCALOOSA 62 42 60 50 62 / 0 10 30 40 90
CALERA 60 40 59 46 60 / 0 0 20 30 80
AUBURN 59 38 60 43 58 / 0 0 10 20 70
MONTGOMERY 63 40 63 47 64 / 0 0 10 20 70
TROY 63 36 63 45 64 / 10 0 10 20 70
&&
.BMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
