FXUS64 KLIX 101309
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
709 AM CST THU DEC 10 2009
.UPDATE...
.SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS MORNING. THE ATMOSPHERE HAS
BECOME DRY AND STABLE WITH A PRECIPITABLE WATER VALUE OF 0.59
INCHES AND A LIFTED INDEX VALUE OF 23.2. AN INVERSION IS PRESENT
NEAR 2600 FEET AND 6500 FEET ALONG WITH STRONG WINDS OUT OF THE
NORTH AT THE SURFACE AND OUT OF THE WEST ALOFT.
&&
.PREV DISCUSSION... /ISSUED 443 AM CST THU DEC 10 2009/
SHORT TERM...
LATEST SURFACE ANALYSIS SHOWED A 1024MB HIGH OVER OKLAHOMA WITH
THE RIDGE AXIS TO THE NORTH CENTRAL GULF. UPPER AIR ANALYSIS
SHOWED A BROAD TROUGH ACROSS THE NORTH TIER AND FAST WESTERLY FLOW
FROM TEXAS TO ALABAMA. ISOTACH ANALYSIS REVEALED MERGING OF THE
NORTH TIER STREAM AND SOUTHERN TIER OVER THE SOUTHERN PLAINS TO MID
MISSISSIPPI VALLEY...BASICALLY AT THE BASE OF THE MAIN TROUGH.
COLD AIR ADVECTION WAS NOT EVIDENT WITH WEST FLOW ALOFT. THE MAIN
TROUGH IS EXPECTED TO MOVE EAST CAUSING THICKNESS LAYERS TO
DECREASE 70M THROUGH FRIDAY. UNDER A DIRTY SOUTHWEST FLOW WITH
CLOUD LAYERS...STRONG COLD AIR ADVECTION WILL KEEP TEMPS DOWN A
TAD THIS AFTERNOON AND FRIDAY AFTERNOON.
LONG TERM...
THE MAIN TROUGH WILL SHIFT EAST. THE SURF HIGH WILL SHIFT EAST TO
THE MID ATLANTIC STATES BY SATURDAY. QUICK WEST FLOW ALOFT OVER
THE SOUTHERN CONUS WILL HELP DEVELOP AN INVERTED TROUGH OVER WEST
GULF SATURDAY. THIS WILL ASSIST THE OLD FRONTAL BOUNDARY TO
RETREAT NORTH ACROSS THE AREA WITH ATM BECOMING MOISTURE LOADED
SATURDAY AFTERNOON AND SATURDAY NIGHT. ERGO...FOG DEVELOPMENT IS
EXPECTED SUNDAY MORNING ACROSS THE AREA. IN ADDITION...THE FIRST
WAVE OF UPPER LEVEL DISTURBANCES WILL TRACK EAST LATE FRIDAY AND
SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON. MARGINAL INSTABILITY
WITH SOUTHERN STREAM WILL YIELD EMBEDDED CONVECTION. AGAIN...PW
VALUES WILL APPROACH 200 PERCENT ABOVE NORM FOR THIS TIME OF
YEAR...ESPECIALLY ACROSS THE SOUTH HALF OF THE FORECAST AREA.
WAVES OF RAINS WILL PRODUCE EXCESSIVE RUNOFF FRIDAY NIGHT THROUGH
SUNDAY. WILL REISSUE THE ESF...INSERT HEAVY RAINFALL WORDING IN
ZONES...HWO AND GRAPHICAST FOR THIS WEEKEND...POSSIBLE FFA THIS
WEEKEND. A BREAK MAY OCCUR LATER SUNDAY BEFORE ANOTHER SYSTEM
TUESDAY. WHILE THIS APPROACHING WAVE IS IN THE NORTHERN
STREAM...THE LENGTH/LAT OF THE WAVE...DENSITY OF THE HIGH MAY
ALLOW FOR A CLEAN PASSAGE OF THE ASSOCIATED FRONT TUESDAY AND
POSSIBLE FREEZES ACROSS THE NORTH ZONES BY DAY 7.
AVIATION...
..12Z AVIATION DISCUSSION...
VFR CONDITIONS TO PERSIST THROUGH TAF PERIOD. WINDS WILL SHIFT FROM
THE NORTH TO THE ENE BY FRIDAY MORNING AND INCREASE TOWARD 15 KNOTS.
CEILINGS AND RAINFALL BEGIN TO INTRUDE THE MSY SITE BY FRI MORNING
BUT SHOULD FALL JUST OUTSIDE CURRENT TAF PERIOD.
COASTAL...
NORTH WINDS OF 15 TO 20 KNOTS REMAIN OVER THE INTERIOR LAKES. HAVE
BROUGHT UP CAUTION STATEMENTS FOR THESE AREAS. 20 TO 25 KNOT WINDS
WILL ALSO CONTINUE OVER THE GULF WATERS. ALL WIND DIRECTIONS WILL
CHANGE FROM NORTH TO THE EAST BY FRIDAY AS A SFC LOW DEVELOPS OVER
THE WESTERN GULF AND MOVES OVER THE MARINE AREA STARTING FRI AND
LASTING INTO THE WEEKEND. WIND SPEEDS WILL INCREASE THROUGH THIS
TIME AS WELL TO 25 KNOTS WITH SOME GUSTS TO 30 KNOTS. A SHORT
REPRIEVE WILL OCCUR SUN NIGHT AND MON BEFORE ANOTHER SYSTEM BEGINS
TO AFFECT THE NORTHERN GULF. A COLD FRONT WILL MOVE THROUGH ON TUE
BRINGING THE SH/TS JUST OUTSIDE THE COASTAL WATERS AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 51 33 48 42 / 0 10 30 70
BTR 53 37 49 45 / 0 10 40 70
MSY 54 42 52 50 / 0 10 40 70
GPT 54 37 48 46 / 10 10 30 70
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR GMZ550-555-570-
575.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR GMZ555-570-575.
&&
$$
