FXUS64 KLIX 111043
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
443 AM CST FRI DEC 11 2009
.DISCUSSION...
LATEST SURFACE ANALYSIS SHOWED A 1030MB HIGH OVER TENNESSEE VALLEY
AND INVERTED TROUGH OVER THE WEST GULF. COLD ATM COLUMN WARM TODAY
WITH INCREASING MOISTURE...NORTHERN ZONES SHOULD REMAIN LIQUID
PRECIP THROUGH THIS MORNING. UPPER AIR ANALYSIS SHOWED THE
SOUTHERN STREAM BAJA CALIFORNIA TO MISSISSIPPI VALLEY AND NORTHERN
STREAM ACROSS THE MID CONUS. SURFACE LOW WILL DRIFT NORTH AND DRAG
DEEP MOISTURE WITH 70F DEWPOINT READINGS ALONG THE COAST BY 18Z
SAT. HOWEVER...PW VALUES INCREASING ABOVE 1.5 INCHES FOR MOST
AREAS NORTHSHORE AND MS COAST SOUTH BY 12Z SAT WEST FLOW WILL
ADVECT IN MOISTURE IN MID LAYER OVER THE AREA. WITH THE WARM FRONT
MOVING NORTH...A SLIGHT INCREASE IN THETA-E VALUES AT 850MB WILL
PROVIDE LAPSE RATE TO SUPPORT SOME CONVECTION LATE THIS EVENING
THROUGH LATE SAT. ROUNDS OF SHOWERS AND A FEW THUNDERSTORMS OVER
COOL SATURATED GROUNDS WILL CAUSE RUNOFF...THEREFORE WILL ISSUE A
FLASH FLOOD WATCH TONIGHT THROUGH SATURDAY WITH 1 TO 3 INCHES AND
ISOLATED 3 TO 5 INCHES. SOME CLEARING LATE SUNDAY. A POSITIVELY
WAVE WILL APPROACH THE AREA LATE MONDAY INTO TUESDAY...INCREASING
RAIN CHANCES MONDAY AND TUESDAY. GFS IS MORE AGGRESSIVE WITH THIS
WAVE DRIVING THE FRONT THROUGH THE AREA TUESDAY WHILE ECMWF IS
SLOWER BUT LOSES DYNAMICS BY WEDNESDAY. WILL LINGER RAIN CHANCES
INTO WEDNESDAY...ESPECIALLY SOUTH HALF.
&&
.AVIATION...
CEILINGS WILL START AT 6KFT TODAY AND LOWER FROM THERE. BY SAT
MORNING CEILINGS FALL TO AROUND 1KFT WITH SOME TEMPO BKN001 MOVING
IN BY AFTERNOON. SOME LIGHT RAIN MAY DEVELOP OVER THE AREA TODAY BUT
THE HEAVIER RAINFALL MOVES IN TONIGHT. THIS IS ALL BROUGHT ON BY A
WARM FRONT MOVING BACK OVER THE AREA. EVEN THOUGH IT IS WELL OUTSIDE
THE 12A TAF PERIOD...WILL BRIEF ON UPCOMING POSSIBILITY OF EVEN
FURTHER DEGRADED TAFS.
ALONG WITH THE RAIN BECOMING MORE WIDESPREAD...THERE SEEMS TO BE A
HINT OF FOG DEVELOPING AS CEILINGS DROP TO THE SFC AS THE WARM FRONT
MOVES OVER SAT AFTERNOON. THE LOW AND ASSOCIATED WARM/COLD FRONT WEAKEN
A BIT AND STALL VERY CLOSE. THIS WILL SET UP AN ONGOING FOG AND RAIN
SCENARIO OR AT BEST VERY LOW CEILINGS UNTIL THE MAIN COLD FRONT
MOVES THROUGH TUE.
.COASTAL...
STRONG WINDS AND ROUGH SEAS CONTINUE TO AFFECT THE GULF WATERS AND
TIDAL LAKES WITH HEADLINES IN EFFECT ACROSS ALL OF THE COASTAL
WATERS THROUGH AT LEAST TONIGHT. AS A WARM FRONT MOVES OVER THE
WATERS SAT...A MORE STABLE MARINE BOUNDARY LAYER WILL ENSUE AS WARM
AIR WILL BE OVER A COLDER WATER SFC. THIS WILL CAUSE A DECOUPLING
EFFECT WHICH WILL KEEP WINDS AT 1KFT FROM REACHING THE SFC.
BASICALLY...WINDS WILL WEAKEN SAT AS THE WARM FRONT PASSES. FOG WILL
BECOME A PROBLEM ESPECIALLY FOR NEAR SHORE SHELF WATERS POSSIBLY AS
SOON AS SAT AFTERNOON. SOME STRONG TS WILL BE POSSIBLE TUE MORNING
AHEAD OF THE MAIN COLD FRONT. AS A STRONG COLD FRONT MOVES THROUGH
TUE...IT WILL FORCE THE LOW CLOUDS AND SH/TS JUST OUTSIDE THE
COASTAL WATERS AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 49 39 52 52 / 40 80 90 60
BTR 50 43 56 53 / 60 80 90 60
MSY 51 47 60 58 / 70 80 90 70
GPT 50 43 55 52 / 40 80 90 70
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH FROM 6 PM FRIDAY TO MIDNIGHT SUNDAY FOR THE
FOLLOWING ZONES: ASCENSION...ASSUMPTION...EAST BATON
ROUGE...EAST
FELICIANA...IBERVILLE...LIVINGSTON...ORLEANS...POINTE
COUPEE...ST. CHARLES...ST. HELENA...ST. JAMES...ST. JOHN
THE BAPTIST...ST. TAMMANY...TANGIPAHOA...UPPER
JEFFERSON...UPPER LAFOURCHE...UPPER PLAQUEMINES...UPPER ST.
BERNARD...UPPER TERREBONNE...WASHINGTON...WEST BATON
ROUGE...AND WEST FELICIANA.
GM...SMALL CRAFT ADVISORY UNTIL 3 AM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20
NM...AND LAKE PONTCHARTRAIN AND LAKE MAUREPAS.
SMALL CRAFT ADVISORY UNTIL NOON SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM...AND
COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST PASS OF
THE MISSISSIPPI RIVER OUT 20 NM.
MS...FLASH FLOOD WATCH FROM 6 PM FRIDAY TO MIDNIGHT SUNDAY FOR THE
FOLLOWING ZONES:
AMITE...HANCOCK...HARRISON...JACKSON...PEARL
RIVER...PIKE...WALTHALL...AND WILKINSON.
GM...SMALL CRAFT ADVISORY UNTIL 3 AM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO
60 NM...COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER TO LOWER ATCHAFALAYA RIVER LA OUT 20
NM...AND LAKE PONTCHARTRAIN AND LAKE MAUREPAS.
SMALL CRAFT ADVISORY UNTIL NOON SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM...AND
COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST PASS OF
THE MISSISSIPPI RIVER OUT 20 NM.
&&
$$
