FXUS64 KLCH 280556
AFDLCH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1156 PM CST FRI NOV 27 2009
.DISCUSSION...
DOPPLER RADAR DEPICTS POSSIBLE VIRGA MOVING NORTHEAST
...APPROACHING THE GOLDEN TRIANGE.
&&
.PREV DISCUSSION... /ISSUED 858 PM CST FRI NOV 27 2009/
UPDATE...
MUCH WARMER THIS EVENING VERSUS YESTERDAY WITH TEMPERATURES IN THE
40S AND 50S. SATELLITE IMAGERY SHOWING A BLANKET OF CIRRUS ACROSS
THE ENTIRE CWA...WITH EVEN THICKER CIRRUS CLOUDS MOVING IN FROM
THE SOUTHWEST. AN EARLIER PEEK OUTSIDE SHOWED CONSIDERABLE VIRGA
FALLING OUT OF THE CIRRUS DECK...AND INDEED RADAR IMAGERY SHOWS
PRECIP ECHOES OVER THE HOUSTON CWA ABOVE 10000 FEET.
HOWEVER...KLCH SOUNDING IS EXTREMELY DRY BELOW 500 MB...AND NONE
OF THE PRECIP IS EXPECTED TO REACH THE SURFACE.
ONLY MADE MINOR TWEAKS TO RAISE SKY COVER AND ADJUST DEWPOINTS
UPWARD TO MATCH LATEST TRENDS. THE WIDESPREAD CLOUD COVER AND
HIGHER DEWPOINTS THIS EVENING WILL HELP TO KEEP LOW TEMPERATURES
OVERNIGHT MUCH WARMER THAN THOSE SEEN FRIDAY MORNING...AND NO
CHANGES WERE MADE TO LOWS FOR TONIGHT. REST OF FORECAST APPEARS TO
BE ON TRACK.
SHAMBURGER
PREV DISCUSSION... /ISSUED 539 PM CST FRI NOV 27 2009/
DISCUSSION...
A SALIENT SHORTWAVE...EMANATING OUT OF THE SIERRA MADRE
ORIENTAL RANGE OF OLD MEXICO...IS GENERATING AND ADVECTING
PACIFIC ALTOSTRATUS ACROSS THE WESTERN UPPER GULF COAST STATES.
OVERCAST MIDTROPOSPHERIC CLOUDS WILL PERSIST THROUGH THIS EVENING...
BREAKING-UP TO SCATTERED AROUND DAWN...AS THE WESTERLY SHORTWAVE
EXITS INTO MISSISSIPPI.
PREV DISCUSSION... /ISSUED 428 PM CST FRI NOV 27 2009/
SYNOPSIS...HIGH PRESSURE WILL BE HANGING IN FOR ONE MORE DAY WITH
SOME LEFT OVER COOL AND DRY CONDITIONS. DEVELOPING LOW PRESSURE
OVER SOUTHERN CALIFORNIA ON SATURDAY WILL MOVE SLOWLY ACROSS
NORTHERN MEXICO OVER THE NEXT SEVERAL DAYS. INCREASING PACIFIC
MOISTURE FROM THIS SYSTEM WILL COMBINE WITH GULF MOISTURE
BEGINNING ON SATURDAY TO GIVE THE AREA INCREASING RAIN CHANCES
INTO EARLY NEXT WEEK IN ADVANCE OF A ROBUST COLD FRONT OUT OF CANADA.
THIS FRONT WILL SLOW UNDER THE SOUTHWESTERLY FLOW ALOFT AS IT
CREEPS THROUGH THE AREA EARLY NEXT WEEK. MEANWHILE UPPER LEVEL DISTURBANCES
PUMPED OUT BY THE MEXICAN LOW WILL COMBINE WITH INCREASING
MOISTURE AND THE FRONT TO PRODUCE A MARKEDLY WET PERIOD FROM LATE
SUNDAY INTO WEDNESDAY.
SHORT TERM...ASSUMED MID AND HIGH CLOUDS WILL LIMIT RADIATIONAL
COOLING TNITE WITH TEMPERATURES RUNNING ABOUT 10 DEGREES WARMER
THAN LAST NIGHT. THE NAM GUIDANCE CAPTURES THIS WELL. TOO DRY IN
THE LOW LEVELS FOR ANY FOG CONCERNS.
LONG TERM...THE GFS AND THE EURO ARE IN BETTER AGREEMENT WITH THE
MOVEMENT OF THE UPPER LEVEL SYSTEM OUT WEST AS WELL AS THE
CANADIAN COLD FRONT EARLY NEXT WEEK. THE SURFACE LOW WHICH IS
EXPECTED TO DEVELOP ALONG THE BOUNDARY IS EXPECTED TO STAY SOUTH
OF THE AREA...MAKING THIS MORE OF A RAIN EVENT WITH LIMITED THUNDER.
THERE IS THE POTENTIAL FOR HEAVY PRECIP SO MENTIONED THIS IN THE
ZONES SINCE THE MOISTURE PROFILE SHOULD BE DEEP WITH GULF MOISTURE
COMBINING WITH MOISTURE FROM THE PACIFIC AND BEING LIFTED ABOVE
THE FRONTAL BOUNDARY. ALSO IMPULSES WILL BE MOVING THROUGH FROM
THE SOUTHWEST DURING THE EVENT. THE SLOW MOVEMENT OF THE FRONT IS
ANOTHER FACTOR FAVORING HEAVY PRECIP. AS WE GET CLOSER IN TIME WE
MAY BE CONSIDERING FLOOD WATCHES.
THE BACK END OF NEXT WEEK LOOKS DRY AND WILL GIVE WELCOME RELIEF
FROM THE PREVIOUS RAINS AS THE UPPER FLOW BECOMES ZONAL AND THEN
TRANSITIONS TO SOUTHWESTERLY. AHEAD OF ANOTHER WESTERN STORM
SYSTEM AFTER NEXT WEEKEND.
JS
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 45 66 56 73 61 / 0 10 10 20 50
KBPT 47 70 59 74 64 / 0 10 10 20 60
KAEX 43 68 52 72 61 / 0 10 10 30 70
KLFT 43 65 54 74 61 / 0 10 10 10 40
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...NONE.
&&
$$
