Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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000
FXUS64 KLIX 271257
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
657 AM CST SAT DEC 27 2014

...SOUNDING DISCUSSION...

ATMOSPHERE IS REALLY STARTING TO JUICE UP THIS MORNING WITH AN
ALMOST 9000 FOOT SATURATED LAYER IN THE LOW-LEVELS. PRECIPITABLE
WATER VALUE HAS CLIMB TO JUST OVER 1.5 INCHES...WHICH IS DOUBLE THE
NORMAL VALUE FOR THIS LATE IN THE YEAR. THIS IS ALSO OVER A ONE
INCH INCREASE COMPARED TO YESTERDAY MORNING/S PW. ALSO
IMPRESSIVE IS THAT THE SURFACE TEMPERATURE IS OVER 13 DEGREES
CELSIUS HIGHER /WARMER/ THAN THIS TIME YESTERDAY. TEMPERATURES IN
MOST OF THE REST OF THE COLUMN ARE ONLY A FEW DEGREES DIFFERENT
FROM YESTERDAY MORNING. NOT MUCH FOR INSTABILITY AT THIS TIME WITH
A LIFTED INDEX OF +3.1 AND NO SURFACE OR MIXED LAYER CAPE SO
THUNDER WILL BE LIMITED TODAY. A VEERING WIND PROFILE WAS FOUND
WITH SOUTHEAST WINDS NEAR THE SURFACE. ABOVE 5500 FEET...A DEEP
LAYER OF WINDS FROM THE SOUTHWEST WAS FOUND...WHICH WILL KEEP
PUMPING MOISTURE INTO THE CENTRAL GULF COAST. A PEAK WIND SPEED OF
93 KNOTS WAS LOCATED AT 39500 FEET.

12Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS MORNING. THE
BALLOON BURST OVER DE SOTO NATIONAL FOREST 73 MILES DOWNRANGE
FROM THE OFFICE AT A HEIGHT OF 20.3 MILES ABOVE THE GROUND. THE
FLIGHT LASTED 100 MINUTES.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 437 AM CST SAT DEC 27 2014/

SHORT TERM...

FLOOD WATCH REMAINS IN EFFECT FOR THE REGION THROUGH 00Z MONDAY.

HEAVY RAINFALL POTENTIAL FOR SOUTHEAST LOUISIANA ANS SOUTHERN
MISSISSIPPI FROM SATURDAY THOUGH SUNDAY EVENING. LOOKS LIKE THE
BULK OF THE HEAVIEST PRECIP WILL OCCUR BETWEEN LATE SATURDAY
AFTERNOON AND EARLY SUNDAY MORNING. FORECAST SOUNDINGS SHOWING
AROUND 2 INCHES OF PW DURING THE SATURDAY AFTERNOON THROUGH
SATURDAY NIGHT TIME FRAME...WHICH IS ABOUT A 2.5 STANDARD
DEVIATION FOR LATE DECEMBER. SOUTHWESTERLY FLOW WILL CONTINUE TO
DRAW DEEP MOISTURE UNTIL THE REGION ALONG WITH A WEAK SURFACE
BOUNDARY OVER THE REGION. DIVERGENCE ALOFT WILL ALSO INCREASE
THROUGHOUT THE DAY TODAY. WITH THAT IN MIND THE POTENTIAL FOR VERY
HEAVY RAINFALL POSSIBLE AND LOCALIZED FLOODING TO BE EXPECTED.

IN ADDITION TO AREA-WIDE WIDESPREAD HEAVY RAINFALL...INCREASED
INSTABILITY AND DIVERGENCE ALOFT CREATE THE POTENTIAL FOR SCATTERED AND
EMBEDDED THUNDERSTORMS BRINGING LOCALIZED HEAVIER RAINFALL AMOUNTS
TO CERTAIN AREAS WITH MOST OF THE ACTIVITY BEING ELEVATED.

..RAINFALL AMOUNTS AND IMPACTS FROM THIS WEEKENDS EVENT...

RAINFALL AMOUNTS EXPECTED TO BE IN THE 2 TO 5 INCH RANGE WITH
LOCAL AMOUNTS OF UP TO 10 INCHES POSSIBLE...WHERE TRAINING OF
HEAVIER BANDS OF HEAVY SHOWERS AND EMBEDDED THUNDERSTORMS TAKE
PLACE. MOST OF THE HEAVIEST RAINFALL IS EXPECTED TO FALL BETWEEN
SATURDAY AFTERNOON AND SATURDAY NIGHT. A BREAK IN THE ACTIVITY IS
POSSIBLE AFTER DAYBREAK SUNDAY THROUGH SUNDAY AFTERNOON BEFORE AN
APPROACHING COLD FRONT MOVES INTO THE AREA. EXPECT TO SEE UP TO AN
ADDITIONAL INCH WITH THE SECOND ROUND AHEAD OF THE FRONT ON SUNDAY
AFTERNOON AND EVENING. IMPACTS OF CONCERN ARE STREET FLOODING AND
THE POTENTIAL FOR FASTER RESPONSE RIVERS AND STREAMS TO RISE ABOVE
FLOOD STAGE.

LONG TERM...

COOLER AND DRIER CONDITIONS EXPECTED TO PERSIST FROM MONDAY
THROUGH AT LEAST MID WEEK. TEMPERATURES WILL REMAIN SLIGHTLY BELOW
NORMAL THROUGH EARLY WEEK WITH A SECONDARY PUSH OF COOLER AIR BY
MID WEEK AS A 1031 MB HIGH PARKS ITSELF OVER THE SOUTHERN PLAIN
STATES. LOWERED POPS FOR NEW YEARS DAY AS BOTH THE EURO AND THE
GFS HAVE BACKED OFF ON POPS FOR THE REGION. THE NEXT SIGNIFICANT
CHANCE OF RAIN EXPECTED AS THE POST NEW YEARS WEEKEND APPROACHES LATER
NEXT FRIDAY AND BEYOND.

AVIATION...

ALTHOUGH SOMEWHAT DELAYED...STEADY DETERIORATION OF CONDITIONS TO
IFR CIGS AND VSBY IS EXPECTED AS RAIN BECOMES INCREASES TOWARDS
DAYBREAK. IT WILL BE DIFFICULT TO SHOW MUCH IMPROVEMENT THROUGH 06Z
SUNDAY AS LARGE SCALE LIFT WILL MAINTAIN HEAVY RAINFALL AND LOW
CEILINGS AS PREDOMINANT CONDITIONS NEXT 24-30 HOURS. 35

MARINE...

WILL LEAVE SMALL CRAFT ADVISORY IN PLACE THROUGH 15Z...AT WHICH TIME
IT WILL LIKELY BE REPLACED WITH EXERCISE CAUTION HEADLINES ON THE
MID MORNING UPDATE. AS GRADIENT RELAXES SLIGHTLY...ANTICIPATE WINDS
WILL DROP BELOW 15 KNOTS BY MID AFTERNOON. COLD FRONT FINALLY PUSHES
THROUGH COASTAL WATERS ON MONDAY...BUT COLD ADVECTION DOES NOT
APPEAR STRONG AT THIS TIME. ANOTHER SOUTHERN STREAM LOW PRESSURE
SYSTEM WILL AFFECT THE AREA TOWARD THE END OF NEXT WEEK...BEYOND THE
SCOPE OF THIS FORECAST PACKAGE. 35

DECISION SUPPORT...

DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
             ASSESSING FLOOD WATCH POTENTIAL FOR THE WEEKEND

DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN  = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE   = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
         WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
         TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED    = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE.


&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  69  61  63  44 / 100  90  70  60
BTR  74  62  64  45 / 100 100  70  50
ASD  71  62  71  49 / 100  90  50  60
MSY  74  63  71  52 / 100  90  50  50
GPT  68  62  72  51 / 100  90  50  60
PQL  69  59  74  50 / 100  90  50  60

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLOOD WATCH UNTIL 6 PM SUNDAY FOR THE FOLLOWING ZONES:
     ASCENSION...ASSUMPTION...EAST BATON ROUGE...EAST
     FELICIANA...IBERVILLE...LIVINGSTON...LOWER
     JEFFERSON...LOWER LAFOURCHE...LOWER PLAQUEMINES...LOWER ST.
     BERNARD...LOWER TERREBONNE...NORTHERN
     TANGIPAHOA...ORLEANS...POINTE COUPEE...SOUTHERN
     TANGIPAHOA...ST. CHARLES...ST. HELENA...ST. JAMES...ST.
     JOHN THE BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER
     LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER
     TERREBONNE...WASHINGTON...WEST BATON ROUGE...AND WEST
     FELICIANA.

GM...SMALL CRAFT ADVISORY UNTIL 9 AM SATURDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
     FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60
     NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM PORT FOURCHON
     TO LOWER ATCHAFALAYA RIVER OUT 20 NM...COASTAL WATERS FROM
     STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO
     60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

MS...FLOOD WATCH UNTIL 6 PM SUNDAY FOR THE FOLLOWING ZONES:
     AMITE...HANCOCK...HARRISON...JACKSON...PEARL
     RIVER...PIKE...WALTHALL...AND WILKINSON.

GM...SMALL CRAFT ADVISORY UNTIL 9 AM SATURDAY FOR THE FOLLOWING
     ZONES: COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
     FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60
     NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM PORT FOURCHON
     TO LOWER ATCHAFALAYA RIVER OUT 20 NM...COASTAL WATERS FROM
     STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM THE SOUTHWEST
     PASS OF THE MISSISSIPPI RIVER TO PORT FOURCHON FROM 20 TO
     60 NM...AND COASTAL WATERS FROM THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER TO PORT FOURCHON OUT 20 NM.

&&

$$







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