FXUS64 KLIX 220230
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
830 PM CST MON DEC 21 2009
.UPDATE...
...SOUNDING DISCUSSION...
NO PROBLEMS WITH THE FLIGHT THIS EVENING. ANOTHER QUIET AND DRY
EVENING WITH A PW OF ONLY 0.29 INCHES. THE ONLY CHANGES SINCE
PREVIOUS SOUNDINGS ARE THE WINDS IN THE LOWEST LEVELS SWITCHING
TO A MORE SOUTHERLY DIRECTION AS THE SURFACE HIGH MOVES OFF TO
OUR EAST AND A RETURN FLOW BEGINS TAKING AFFECT.
&&
.PREV DISCUSSION... /ISSUED 326 PM CST MON DEC 21 2009/
SHORT TERM...
ANOTHER FOGGY NIGHT IS STORE. WILL LEAVE EVENING SHIFT TO TAKE
ANOTHER LOOK AT POSSIBILITY OF ISSUING DENSE FOG ADV. SOME
MOISTURE ADVECTION WILL BEGIN TONIGHT AND WINDS WILL BEGIN TO
INCREASE TUE BUT SHOULD BE QUITE BREEZY WED AS MOISTURE LOADING
WILL BE AT FULL FORCE. SOME SHOWER ACTIVITY CAN BE EXPECTED WITH THE
ABUNDANT MOISTURE ADV WED MAINLY OVER THE NORTHWESTERN 1/3 OF THE
AREA...BUT THE MAIN SHOW DOES NOT START TIL AFTER DARK WED NIGHT.
FIRST GROUP OF PREFRONTAL SH/TS SHOULD BEGIN OVER THE
BRETON/CHADELEUR SOUND AREAS AND MOVE NORTH THROUGH THE MORNING
HOURS THU. A SQUALL LINE WILL THEN MOVE INTO THE PICTURE BEHIND
THIS AREA BY LATE MORNING TO NOON.
NOW WITH ALL THAT SAID...NUMBERS LOOK EXCELLENT FOR SVR WX WITH ONLY
A FEW VARIABLES. HELICITY BEING THE MOST PROMENANT. LINEAR FORCING
ALONG THE FRONT AND STRONG WIND SPEEDS RIGHT UP TO THE AXIS
PROVIDING A SHARP HODOGRAPH CALLING FOR A STRONG SQUALL LINE.
NUMBERS ARE FAIRLY POOR ON OTHER PARAMETERS THOUGH. LOOKS LIKE
TOO MUCH SPEED SHEAR PROVIDING THE HIGH HELICITY NUMBERS. WOULD
LIKE TO SEE STRONG VEERING PRODUCING THESE HIGHER NUMBERS TO GET A VERY
GOOD SHOT AT TORNADIC ACTIVITY AHEAD OF THE FRONT. STABILITY AT
THE SFC ALSO HOLDS FAIRLY TIGHT...BUT THE 850 JET WILL BE VERY
STRONG. WILL NOT BACK OFF ON ANY PREFRONTAL SEVERE WORDING AT THIS
POINT BUT CONCENTRATION WILL FALL MORE ON SEVERITY ASSOCIATED WITH
THE MAIN SQUALL LINE THU AS IT SHOULD BE ABLE TO KICK OFF SOME
STRONG DAMAGING WINDS AND A POSSIBLE TORNADO DUE TO SOLENOIDAL
ADVECTION. STRONG NORTHERLY WINDS WILL MOVE IN BEHIND TO BRING
SOME VERY COLD AIR TO THE REGION.
LONG TERM...
ANOTHER STRONG SYSTEM IS LOOKING TO DEVELOP AND MOVE INTO THE
PICTURE AROUND TUE OR WED OF NEXT WEEK. THIS FALLS WELL OUTSIDE OF
OUR FCAST PACK BUT THIS SYSTEM ALSO LOOKS INTERESTING AS THE SFC
LOW MAY MOVE VERY CLOSE TO THE AREA.
AVIATION...
MAIN FORECAST PROBLEM IS FOG TONIGHT AND TUESDAY MORNING. GROUND
REMAINS QUITE MOIST AND COOL...AND WEAK PRESSURE GRADIENT WITH
SURFACE HIGH PRESSURE JUST TO THE EAST WILL FAVOR A COMBINATION OF
RADIATIONAL COOLING AND SLIGHT ADVECTION OF MOISTURE IN THE NEAR
SURFACE LAYER. FORECAST CONFIDENCE ON HOW WIDESPREAD THE FOG BECOMES
AND WHICH TAF AIRPORTS ARE IMPACTED IS LOW...BUT BELIEVE LIFR TO
VERY LOW IFR CONDITIONS WILL DEVELOP BY 08-11Z AND PERSIST THROUGH
14-15Z AT KMCB AND KGPT WITH MVFR CONDITIONS FOR AT LEAST A COUPLE
HOURS BEFORE AND AFTER. MVFR TO IFR CONDITIONS ARE ALSO LIKELY AT
KBTR AND KMSY...BUT THERE IS AT LEAST A CHANCE OF LIFR. 22/TD
MARINE...
LIGHT WINDS AND LOW SEAS CONDITIONS TODAY WILL START TO DETERIORATE
TONIGHT AND ESPECIALLY TUESDAY INTO WEDNESDAY AS EASTERLY TO
SOUTHEASTERLY RETURN FLOW TAKES PLACE AHEAD OF THE NEXT STORM
SYSTEM. WINDS AND SEAS SHOULD INCREASE TO SMALL CRAFT ADVISORY
LEVELS EITHER LATE TUESDAY NIGHT OR WEDNESDAY NIGHT THEN CONTINUE
THROUGH EARLY CHRISTMAS MORNING WITH PRE-FRONTAL STRONG ONSHORE FLOW
FOLLOWED BY STRONG OFFSHORE FLOW POST-FRONTAL THURSDAY AND COLD HIGH
PRESSURE BUILDING INTO THE NORTH GULF INTO SATURDAY MORNING. TD/22
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 37 66 53 66 / 0 0 30 50
BTR 41 69 56 69 / 0 10 30 50
MSY 44 68 56 72 / 0 0 20 40
GPT 40 65 53 68 / 0 0 10 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
