FXUS64 KLIX 251256
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
656 AM CST FRI DEC 25 2009
.UPDATE...
.SOUNDING DISCUSSION...
DRY AIR HAS MOVED INTO THE AREA ABOVE 900 MB...PRECIPITABLE WATER
VALUE IS DOWN TO 0.41 INCHES. A LARGE INVERSION IS PRESENT NEAR
3500 FEET ALONG WITH WEST WINDS UP TO 4500 FEET AND STRONG
SOUTHWEST WINDS ALOFT. EXPECT A BEAUTIFUL CHRISTMAS DAY.
&&
.PREV DISCUSSION... /ISSUED 423 AM CST FRI DEC 25 2009/
SHORT TERM...
QUITE A CHANGE ON THIS CHRISTMAS DAY MORNING FROM 24 HRS AGO. TEMPS
ARE 20 TO 30 DEGREES COOLER AND TD/S CONTINUE TO PLUMMET AS THE COLD
FRONT IS NOW WELL EAST OF THE AREA AND CONTINENTAL POLAR AIRMASS IS
MOVING INTO THE CWA. GOING TO BE LUCKY TO SEE A 10 DEGREE RISE IN
TEMPS BY AFTERNOON. 11-3.9U SAT SHOWS LARGE AREA OF LOW CLOUDS
EXTENDING FROM EASTERN OK TO NEAR LCH AND MOVING EAST. THIS BACK
EDGE OF CLEARING SHOULD REACH WESTERN PORTIONS OF THE CWA A COUPLE
HRS AFTER SUNRISE AND PROGRESS EAST WITH THE ENTIRE CWA LEFT WITH
ONLY A FEW HIGH CLOUDS BY MID AFTN. NWRLY WINDS WILL DROP OFF TO
NEAR CALM AROUND SUNSET AS SFC RIDGE BECOMES CENTERED OVER THE AREA.
CALM WINDS AND CLEAR SKIES WILL SET THE STAGE FOR GOOD RADIATIONAL
COOLING OVERNIGHT. WITH DEWPOINTS IN THE MID TO UPPER 20S...TEMPS
WILL FALL INTO THE UPPER 20S MAINLY ALONG AND NORTH OF I-12 TO MID
30S ALONG THE LA COAST.
LONG TERM...
UPPER LOW CURRENTLY CENTERED NEAR THE AR/MO BORDER WILL ROTATE
FARTHER NORTHWARD AND MERGE WITH SECONDARY LOW THATS TRACKING
SOUTHWARD ACROSS THE NORTHERN GREAT PLAINS. THIS RESULTANT DEEPENING
LOW WILL SLOWLY PROGRESS TOWARDS THE GREAT LAKES REGION LATER THIS
WEEKEND. MEANWHILE... A SFC LOW IS PROGGED TO DEVELOP IN THE WESTERN
GULF AND APPROACH THE AREA. MAIN DIFFERENCE IN TODAY FROM 24HRS AGO IS
THE CLOSER PROXIMITY TO THE CWA THAT THIS LOW IS EXPECTED TO REACH.
IT APPEARS THAT SFC RIDGE OVER THE AREA WILL EJECT QUICKER THAN
EXPECTED AND ALLOW A MORE NORTHERLY PROTRUSION OF MOISTURE. WITH A
SOMEWHAT DRASTIC CHANGE IN PREVIOUS RUNS...DIDN/T FEEL COMFORTABLE
GOING WITH STRICTLY GUIDANCE POPS AND STAYED IN THE 20 TO 30PCT
RANGE AS OPPOSED 40-50 FOR MAV AND 60/S WITH THE MET. ECMWF KEEPS
THE ARE MUCH DRIER WITH LITTLE IF ANY QPF. SO...WOULD HAVE TO SAY
FCST IS A COMPROMISE BTW ECMWF AND MAV. DID CHECK MODEL SOUNDINGS
AND LOWER LEVELS LOOK TO BE TOO WARM FOR ANY OTHER TYPE PRECIP OTHER
THAN LIQUID. TEMPS THROUGH THE WEEKEND WILL REMAIN BELOW NORMAL WITH
A SLOW MODERATION THRU SUNDAY FROM TODAY. SECONDARY SURGE OF COLD
AIR WILL MOVE IN LATE SUNDAY TO SUNDAY NIGHT. FOR ONE THIS WILL DROP
TEMPS BACK SEVERAL DEGREES BY MONDAY MORNING AND ABOUT 3-5 FOR
HIGHS. SECONDLY...THIS WILL SHOVE THE SFC LOW AND WHAT LITTLE
MOISTURE RETURN WE GET BACK OUT INTO THE GULF.
THE NEXT IMPACTS FOR THE AREA COME MID WEEK AS A SOUTHERLY STREAM
TROUGH TRACKS ACROSS THE US/MEXICO BORDER. SHOULD HAVE MORE MOISTURE
ON TAP COMPARED TO SAT NIGHT AND RAIN CHANCES WILL BE ON THE
INCREASE. THERE ARE SOME SLIGHT DIFFERENCES IN MODEL SOLUTIONS ON
TIMING BUT NOT MUCH.
MEFFER
AVIATION...
MVFR TO VFR CIGS AROUND 3000 FEET WILL CLEAR OUT OF KBTR-KMSY BY
14-15Z...AND KMCB-KGPT 16-17Z. WINDS WILL CONTINUE TO GUST TO 17 TO
22 KNOTS THIS MORNING...ESPECIALLY EARLY. MOSTLY CLEAR VFR WEATHER
WILL PREVAIL THIS AFTERNOON THROUGH SATURDAY. 22/TD
MARINE...
STRONG LOW PRESSURE SYSTEM OVER THE MID MISSISSIPPI VALLEY AND HIGH
PRESSURE OVER TEXAS WILL CONTINUE TO PRODUCE SMALL CRAFT ADVISORY
CRITERIA WINDS THIS MORNING BEFORE WINDS EASE TO 10 TO 15 KNOTS THIS
AFTERNOON. MARINE OBSERVATIONS SHOW SEAS STILL 7 TO 10 FEET...AND
THESE WILL GRADUALLY DROP BELOW 7 FEET OVER THE INNER WATERS BY LATE
AFTERNOON...AND OVER THE OUTER WATERS DURING THE EVENING. COLD HIGH
PRESSURE WILL SETTLE OVER THE CENTRAL GULF COAST REGION LATER TODAY
INTO SATURDAY...BUT THE PRESENCE OF THE COLD AIR WILL NOT LET WINDS
GET TOO LIGHT OVER THE WATER. A WEAK AREA OF LOW PRESSURE MAY
DEVELOP OVER THE NORTHWEST GULF SATURDAY NIGHT AND MOVE EAST ACROSS
THE NORTH GULF SUNDAY AS COOL HIGH PRESSURE LINGERS TO THE NORTH
OVER THE GULF COAST STATES. WINDS ARE LIKELY TO RETURN TO EXERCISE
CAUTION OR POSSIBLY SMALL CRAFT ADVISORY CRITERIA AT TIMES SATURDAY
NIGHT INTO MONDAY MORNING. 22/TD
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 47 28 51 35 / 0 0 10 20
BTR 48 31 54 37 / 0 0 10 30
MSY 50 36 54 42 / 0 0 10 30
GPT 51 30 52 40 / 0 0 10 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LAZ066-070.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ550-555.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR GMZ570-575.
SMALL CRAFT ADVISORY UNTIL 9 AM CST THIS MORNING FOR GMZ530.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ555.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR GMZ575.
&&
$$
