Flash Flood Warning 22, NWS New Orleans, LA

000 
WGUS74 KLIX 061905
FFSLIX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
205 PM CDT SUN SEP 6 2009

LAC051-071-075-087-061915-
/O.CAN.KLIX.FF.W.0022.000000T0000Z-090906T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ST. BERNARD LA-JEFFERSON LA-ORLEANS LA-PLAQUEMINES LA-
205 PM CDT SUN SEP 6 2009

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR EXTREME
NORTHWESTERN PLAQUEMINES...WESTERN ORLEANS...NORTH CENTRAL JEFFERSON
AND WEST CENTRAL ST. BERNARD PARISHES...

THE STORMS THAT PROMPTED THE WARNING HAS MOVED SOUTH AND OUT OF THE 
WARNED AREA. 

LAT...LON 2995 9017 3011 8990 3007 8980 2975 8998

$$
BANNAN

AREA FORECAST DISCUSSION...AVIATION UPDATE
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1231 PM CDT SUN SEP 6 2009

.AVIATION...CONVECTION IS POPPING UP AROUND THE AREA AGAIN AND THIS
WILL CAUSE SOME PROBLEMS FOR OUR TAF LOCATIONS THROUGHOUT THE AFTN
AND INTO THE OVERNIGHT HRS. OUTSIDE OF CONVECTION IT HAS MOSTLY BEEN
VFR CONDITIONS BUT MVFR CIGS HAVE OCCURRED AT TIMES. THIS WILL
CONTINUE TO BE THE CASE AS CIGS WILL LIKELY RANGE FROM 2K-3500 FT
OUTSIDE OF ANY RAIN. OF COURSE CIGS AND VISBIES WILL BOTH DROP WITH
ANY STORM. RAIN COULD VERY EASILY BE HEAVY DROPPING VISBIES DOWN
INTO IFR AND EVEN LIFR AT TIMES. ALL SITES SHOULD HAVE TO DEAL WITH
AT LEAST VCTS SOMETIME THIS AFTN BUT ONCE WE MOVE INTO THE EVN...AS
HAS BEEN THE CASE THE LAST FEW NIGHTS CONVECTION SHOULD BEGIN TO
CONSOLIDATE CLOSER TO THE COAST. WITH THAT MSY AND GPT COULD HAVE
ISSUES FROM SHRA/TSRA MUCH OF THE NIGHT BUT ESPECIALLY AFTER 6Z. BTR
AND MCB COULD STILL SEE SOME ISSUES FROM LIGHT BR AND EVEN LOW
CLOUDS. FCST SNDGS SUGGEST LOW CLOUDS POSSIBLY DEVELOPING AFTER 6/7Z
MAYBE AS LOW AS 2-500 FT. I WILL JUST KEEP TEMPO SCT IN RIGHT NOW
BUT I WOULD NOT BE SURPRISED TO SEE SOME BKN CIGS BELOW 1K FT AT
THESE TWO SITES.  /CAB/

&&

.DISCUSSION...SOUNDING DISCUSSION...

THE ATMOSPHERE REMAINS MOIST WITH A FEW SMALL POCKETS OF DRY AIR
PRESENT...PRECIPITABLE WATER VALUE IS 2.06 INCHES. A LAYER OF
ALTOCUMULUS CLOUDS NEAR 8900 FT ARE PRESENT THIS MORNING AS
REFLECTED IN THE SOUNDING. SHOWERS AND A FEW THUNDERSTORMS
DEVELOPED DURING THE NIGHT OVER THE COASTAL AREAS BUT HAVE SINCE
DISSIPATED AND ARE EXPECTED TO FIRE UP AGAIN LATER IN THE
DAY...SIMILAR TO YESTERDAY. AN INVERSION IS PRESENT NEAR 750 FEET
ALONG WITH WINDS OUT OF THE SOUTH IN THE LOWER LEVELS AND OUT OF
THE WEST IN THE MID AND UPPER LEVELS.

&&

.PREV DISCUSSION... /ISSUED 414 AM CDT SUN SEP 6 2009/

SHORT TERM...

A SHORT WAVE TROUGH CURRENTLY DIGGING INTO THE SOUTHERN PLAINS
WILL BE THE PRIMARY PLAYER ACROSS THE AREA THROUGH THE REMAINDER
OF THE HOLIDAY WEEKEND. IN ADDITION...A SURGE OF DEEP TROPICAL
MOISTURE HAS OVERSPREAD THE REGION...AS EVIDENT IN THE 00Z
SOUNDING DEPICTING PW VALUES IN EXCESS OF 2 INCHES. WITH STRONG
MID AND UPPER LEVEL OMEGA VALUES ASSOCIATED WITH A BROAD ZONE OF
POSITIVE VORTICITY ADVECTION IN ADVANCE OF THE SHORT WAVE
TROUGH...THERE WILL BE MORE THAN ENOUGH DYNAMIC SUPPORT FOR
CONVECTIVE ACTIVITY TODAY INTO TOMORROW. TODAY LOOKS TO BE THE
HIGHEST COVERAGE DAY...AS THE PLUME OF DEEP TROPICAL MOISTURE WILL
POSITIONED DIRECTLY OVER THE REGION. BOTH THE NAM AND GFS THEN
SHOW THE PLUME OF MOISTURE SHIFT SLIGHTLY TO THE EAST...TOWARD THE
FLORIDA PANHANDLE GOING INTO TOMORROW AND TUESDAY. THIS WILL LEAD
TO SLIGHTLY LOWER POPS FOR LABOR DAY ITSELF. OVERALL...HAVE WENT
WITH CATEGORICAL POPS FOR EASTERN AND SOUTHERN ZONES...WITH LIKELY
POPS ELSEWHERE. HEADING INTO TONIGHT...EXPECT LIKELY POPS TO
CONTINUE OVER COASTAL AREAS...AS THE TROPICAL MOISTURE WILL BE
MOST PREVALENT IN THIS REGION. THESE LIKELY POPS WILL PERSIST INTO
TOMORROW. HOWEVER...OVER NORTHERN AND WESTERN ZONES...A SLIGHTLY
DRIER AIRMASS WILL DROP POPS BACK INTO THE CHANCE CATEGORY FOR
TONIGHT AND TOMORROW. GIVEN THE DEEP MOISTURE IN PLACE...THERE
WILL BE THE POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL IN ISOLATED
SPOTS TODAY. TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL
TODAY AND TOMORROW ACROSS THE FORECAST AREA.

HEADING INTO MONDAY NIGHT AND TUESDAY...CONDITIONS WILL BEGIN TO
CHANGE A BIT. THE SHORT WAVE TROUGH AXIS WILL SHIFT TO THE EAST
OF THE REGION. HOWEVER...STRONG UPPER LEVEL TROUGHING WILL
CONTINUE TO DOMINATE THE EASTERN HALF OF THE NATION...WITH
NORTHERLY FLOW TAKING HOLD OF THE GULF SOUTH. IN THE LOW
LEVELS...A WEAK SURFACE RIDGE WILL BUILD OVER THE AREA. IN
ADDITION...A WEAK BOUNDARY...ALMOST LIKE A BACK DOOR FRONT...BUT
NOT STRONG ENOUGH OR DEEP ENOUGH TO WARRANT BEING CALLED
THAT...WILL STALL ALONG THE LOUISIANA COAST. THIS ZONE OF
CONVERGENCE WILL SERVE TO KEEP CHANCE POPS IN FOR LAND
ZONES...WITH HIGHER POPS OVER THE COASTAL WATERS. IN
ADDITION...SOME WEAK DRY AIR ADVECTION IN THE MID AND UPPER LEVELS
OF THE ATMOSPHERE WILL PROVIDE SOME WEAK CAPPING DURING THE
DAY...ESPECIALLY OVER FAR NORTHERN ZONES. HOWEVER...THE CAP WILL
BE WEAK ENOUGH TO BE EASILY OVERCOME ON TUESDAY. TEMPERATURES WILL
CONTINUE TO BE NEAR NORMAL MONDAY NIGHT INTO TUESDAY.

LONG TERM...

WEDNESDAY THROUGH FRIDAY WILL BE VERY SIMILAR TO TUESDAY...AS WEAK
SURFACE AND MID-LEVEL RIDGING...COMBINED WITH CONTINUED UPPER
LEVEL TROUGHING DOMINATES THE REGION. EASTERLY FLOW WILL BE IN
PLACE IN THE LOW TO MID-LEVELS...WITH NORTHWESTERLY FLOW ALOFT.
MODEL SOUNDINGS INDICATE CONTINUED DRY AIR IN THE MID AND UPPER
LEVELS WITH AMPLE LOW LEVEL MOISTURE IN PLACE. OVERALL...EXPECT
LOW END CHANCE POPS EACH DAY. THE CONVECTION WILL BE DIURNALLY
INDUCED...WITH FORMATION MOST LIKELY ALONG ANY PREEXISTING
BOUNDARIES SUCH SEABREEZE FRONTS OR OUTFLOW BOUNDARIES.
TEMPERATURES WILL BE NEAR NORMAL THROUGH THE PERIOD.

GOING INTO THE WEEKEND...BOTH THE GFS AND ECMWF DEPICT ANOTHER
VERY STRONG UPPER LEVEL LOW DIVING SOUTHWARD INTO THE NATION FROM
CANADA. THE TIMING IS FAIRLY CLOSE...BUT THE EXACT PLACEMENT OF
THE LOW IS OFF AT THIS TIME. SINCE THE MODELS ARE IN FAIRLY GOOD
AGREEMENT ON A TROUGH DEVELOPING...CONFIDENCE IS AVERAGE HEADING
INTO THE EXTENDED PERIOD. THE FLOW WILL TURN MORE WESTERLY ON
SATURDAY AS THE UPPER LEVEL TROUGH DIGS SOUTHWARD. A PLUME OF
TROPICAL MOISTURE WILL RIDE ON THE BACK OF THIS SOUTHWEST FLOW
INTO THE AREA. AT THE SAME TIME...A BROAD AREA OF LIFT IN ADVANCE
OF THE TROUGH WILL DEVELOP OVER THE AREA. GIVEN THIS...AND AN
APPROACHING SURFACE FRONT...HAVE WENT WITH HIGH END CHANCE POPS
FOR SATURDAY AND SUNDAY.

&&

.MARINE...
LIGHT TO OCCASIONALLY MODERATE SOUTHEAST TO EAST FLOW WILL PREVAIL
ACROSS THE COASTAL WATERS THROUGH THE MIDDLE OF THE WEEK. A WEAK
SURFACE TROUGH SITUATED OVER THE NORTHWEST GULF...ALONG WITH AMPLE
MOISTURE AND WEAK UPPER LEVEL DISTURBANCES...WILL KEEP THE WEATHER
UNSETTLED THROUGH THE EARLY PART OF THE WORK WEEK. RAIN CHANCES WILL
DIMINISH SOMEWHAT BY THE MIDDLE OF THE WEEK. SEAS WILL GENERALLY BE
3 FEET OR LESS DURING THE PERIOD. 11

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  87  68  88  68 /  70  50  40  20
BTR  88  70  90  69 /  70  50  40  20
MSY  87  74  88  74 /  80  60  60  30
GPT  87  73  87  72 /  80  60  60  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&

CAB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1120 AM CDT SUN SEP 6 2009

GMZ530-550-555-570-575-LAZ034>040-046>050-056>070-MSZ068>071-077-
080>082-071630-
LAKE PONTCHARTRAIN AND LAKE MAUREPAS-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM-
COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER OUT 20 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO LOWER ATCHAFALAYA RIVER LA FROM 20 TO 60 NM-
COASTAL WATERS FROM PASCAGOULA MS TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER FROM 20 TO 60 NM-POINTE COUPEE-WEST FELICIANA-
EAST FELICIANA-ST. HELENA-TANGIPAHOA-WASHINGTON-ST. TAMMANY-
IBERVILLE-WEST BATON ROUGE-EAST BATON ROUGE-ASCENSION-LIVINGSTON-
ASSUMPTION-ST. JAMES-ST. JOHN THE BAPTIST-UPPER LAFOURCHE-
ST. CHARLES-UPPER JEFFERSON-ORLEANS-UPPER PLAQUEMINES-
UPPER ST. BERNARD-UPPER TERREBONNE-LOWER TERREBONNE-
LOWER LAFOURCHE-LOWER JEFFERSON-LOWER PLAQUEMINES-
LOWER ST. BERNARD-WILKINSON-AMITE-PIKE-WALTHALL-PEARL RIVER-
HANCOCK-HARRISON-JACKSON-
1120 AM CDT SUN SEP 6 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF COASTAL WATERS
OF SOUTHEAST LOUISIANA AND SOUTH MISSISSIPPI...SOUTHEAST
LOUISIANA AND SOUTHERN MISSISSIPPI.

.DAY ONE...THIS AFTERNOON AND TONIGHT
NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS AFTERNOON
INTO EARLY THIS EVENING. THESE THUNDERSTORMS ARE EXPECTED TO
REMAIN BELOW SEVERE LIMITS...BUT COULD PRODUCE LOCALLY HEAVY
RAINFALL...FREQUENT LIGHTNING AND WIND GUSTS TO 40 MPH.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY
SCATTERED THUNDERSTORMS ARE EXPECTED ON MONDAY...MAINLY DURING THE
AFTERNOON AND EVENING HOURS. THUNDERSTORMS ARE EXPECTED TO BE LESS
NUMEROUS FOR TUESDAY THROUGH THE END OF THE WEEK. WHILE A STRONG
THUNDERSTORM OR TWO ARE POSSIBLE...WIDESPREAD SEVERE WEATHER IS
NOT EXPECTED. THE STRONGEST STORMS WILL PRODUCE BRIEF HEAVY
RAIN...FREQUENT LIGHTNING STRIKES...AND GUSTY WINDS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED.