FXUS64 KLIX 031057
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
457 AM CST THU DEC 3 2009
.SHORT TERM...
THE UPPER TROUGH THAT MOVES THROUGH TO GIVE US A LIGHT SNOW IS
CURRENTLY DIGGING THROUGH COLORADO AND WYOMING THIS MORNING. THIS
IS OCCURRING INSIDE A LARGER ROSSBY WAVE ALREADY SET UP OVER 80%
OF THE CONUS. THE SMALLER UPPER TROUGH IS THE ONE THAT IS FCAST TO
SHARPEN AS IT DIGS SOUTHWARD AND BEGIN LIFTING OUT OF THE DEEP
SOUTH BY SAT MORNING. BUT BEFORE THAT IT WILL PROVIDE ENOUGH
HEIGHT FALLS AND LAYER LIFTING TO CAUSE SOME WINTER WX FOR THE
AREA. PROBLEM IS OBVIOUS...MOISTURE. THERE WILL BE SOME STRONG
WIND SPEEDS MOVING THROUGH AT JET LEVEL FRI NIGHT PROVIDING THE
LIFTING MECHANISM WHICH WILL SQUEEZE ANY MOISTURE FROM THE
ADJOINING LAYERS BELOW. PROBLEM WITH GETTING ANY STRONG SNOWFALL
WILL BE THE DISCONNECTION OF THE SFC LOW AND THE UPPER TROUGH
WHILE MOVING OVER OUR AREA. WITHOUT THE CONNECTION TO THE SFC
LOW...THERE CAN BE LITTLE MOISTURE BROUGHT INTO THE MID LEVELS OF
THE TROUGH. SLANTWISE CONVECTION WILL BE AT A MINIMUM UNTIL THE
TROUGH MOVES PAST. THE THING WE WOULD LOOK FOR TO GET A GOOD
AMOUNT OF SNOW IS AN UPPER LOW CONNECTED WITH A SFC LOW OVER THE
GULF. THE UPPER LOW WOULD HELP BRING MOISTURE BACK INTO THE LOWER
HEIGHTS TO THE WEST WHERE THE AIR IS COLDER. THE SLANTWISE
CONVECTION AND UPPER LOW WOULD WRAP THIS UNENDING MOISTURE BACK
INTO THIS AREA AND LET IT FALL THROUGH THOSE COLD LAYERS.
WITH THE SETUP WE ARE ABOUT TO SEE...WE WOULD SEE THE STRONG JET
LEVEL WINDS LIFTING AND SQUEEZING OUT WHAT AVAILABLE MOISTURE
THERE IS IN A LINEAR PATTERN...SIMPLY CAUSING SNOW STREAKS. IF WE
CAN SEE ONE OF THESE STREAKS SET UP OVER ANY ONE AREA FOR ABOUT AN
HOUR...WE MAY SEE SOME ACCUMULATIONS IN THE HALF TO INCH RANGE.
THE GOING FCAST LOOKS GOOD THOUGH AND HAVE CHANGED A FEW THINGS
MAINLY SHOWING THE DIFFERENT MIXED WINTRY PRECIP TYPES AND WHERE
HEIGHTS SUPPORT THEIR EXISTANCE. THE MIX IS NOT WITH US LONG AND
TO SEE IT YOU WILL NEED TO STAY AWAKE INTO THE EVENING AND
MORNING HOURS FRI NIGHT EARLY SAT MORNING.
THE BIGGEST ISSUES ARE GOING TO BE WITH ELEVATED ROADWAYS. EVEN IF
A MIX OF SLEET AND SNOW/RAIN IS OCCURRING...THERE WILL BE THE
POTENTIAL FOR SOME OF THIS TO FREEZE ON ELEVATED ROADWAYS.
DETAILING THE AREA OF GREATEST POTENTIAL TO SEE THIS WILL BE
EXAMINED AND TRANSMITTED LATER TODAY OR TONIGHT.
.LONG TERM...
VERY PROGRESSIVE PATTERN SETTING UP. ANOTHER DISTURBANCE RACES
THROUGH SUN NIGHT INTO MON MORNING. THEN ANOTHER COLD FRONT MOVES
THROUGH ON TUE. HIGH PRESSURE THEN SETTLES IN FOR THE NEXT SEVERAL DAYS.
&&
.AVIATION...
SATELLITE SHOWS THE LOW CLOUDS GOT A BIG HOLE AND TEMPORARILY
CLEARED KBTR AND KMCB...HOWEVER...CLOUDS ARE MOVING BACK INTO KMCB
AND WILL LIKELY MOVE BACK INTO KBTR IN THE NEXT FEW HOURS. KMSY MAY
SCATTERED OUT FOR A COUPLE HOURS...BUT THEN MVFR CIGS ARE LIKELY
AGAIN BEFORE CLEARING OUT THIS AFTERNOON. KGPT MAY KEEP THE CIGS
AROUND ALL DAY AND POSSIBLY TONIGHT AS WELL. NO VSBYS RESTRICTIONS
ARE EXPECTED. 22/TD
&&
.MARINE...
BUILDING HIGH PRESSURE AND A RELAXING PRESSURE GRADIENT ARE CAUSING
WINDS AND SEAS TO SUBSIDE...AND SMALL CRAFT EXERCISE CAUTION WILL BE
ALLOWED TO EXPIRE BEFORE SUNRISE. THE WINDOW OF LOWER WINDS WILL BE
SHORT LIVED AS HIGH PRESSURE STARTS TO INTERACT WITH DEVELOPING LOW
PRESSURE EARLY FRIDAY. SMALL CRAFT EXERCISE CAUTION CONDITIONS OVER
THE LAKES...AND SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED TO
DEVELOP LATE TONIGHT AND ESPECIALLY FRIDAY AND FRIDAY NIGHT AS THE
LOW PRESSURE AREA MOVES ACROSS THE NORTHERN/CENTRAL GULF OF MEXICO.
SUSTAINED WINDS APPROACHING 30 KNOTS FRIDAY NIGHT AND SATURDAY
MORNING MAY PRODUCE WIND GUSTS TO GALE FORCE /34 KNOTS/...BUT HAVE
OPTED NOT TO ISSUE A GALE WATCH AT THIS TIME. WINDS AND SEAS WILL
LOWER BELOW SMALL CRAFT CRITERIA AGAIN SATURDAY AFTERNOON WITH
LIGHTER WINDS EXPECTED ON SUNDAY. 22/TD
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 57 36 50 31 / 0 10 30 60
BTR 59 38 52 33 / 0 10 40 60
MSY 58 44 54 37 / 0 10 30 60
GPT 60 39 54 35 / 0 10 20 60
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
