River Flood Warning 34, NWS New Orleans, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
351 AM CDT SUN MAY 17 2015

.DISCUSSION...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO AFFECT
AREAS OF COASTAL MISSISSIPPI EARLY THIS MORNING WITH NEW
DEVELOPMENT NOW OCCURRING ACROSS SECTIONS OF THE NORTHSHORE. THIS
ACTIVITY IS OCCURRING WITHIN A PERSISTENT AREA OF LOW LEVEL
CONVERGENCE. OVER THE PAST 24 HOURS OF SO...AND ESPECIALLY SINCE
YESTERDAY AFTERNOON ACROSS COASTAL MISSISSIPPI...SOME HEAVY
RAINFALL TOTALS HAVE OCCURRED ACROSS SECTIONS OF THE FORECAST
AREA. IN PARTICULAR...DUAL POL STORM TOTALS WERE INDICATING 6 TO
10 INCHES OVER NORTHERN SECTIONS OF JACKSON...HARRISON AND HANCOCK
COUNTIES...WITH SECTIONS OF PEARL RIVER COUNTY...NORTHEASTERN ST.
TAMMANY PARISH AND EASTERN WASHINGTON PARISH ALSO HAVING RECEIVED
5 TO 10 INCHES. A FEW GROUND TRUTH REPORTS IN THESE AREAS SUPPORT
THE RADAR ESTIMATES. SINCE THE GROUND IS OBVIOUSLY SATURATED IN
THESE AREAS WITH SOME RIVER FLOODING ALREADY OCCURRING...AND MORE
SCATTERED AND EFFICIENT RAIN PRODUCING CONVECTION IN THE FORECAST
FOR TODAY...IT SEEMS PRUDENT TO EXTEND THE CURRENT FLASH FLOOD
WATCH CURRENTLY IN EFFECT FOR COASTAL MISSISSIPPI THROUGH TODAY
AND EXPAND THE WATCH WESTWARD TO INCLUDE PEARL RIVER COUNTY AND
ST. TAMMANY AND WASHINGTON PARISHES.

DAILY BOUTS OF CONVECTION WILL CONTINUE TO PLAGUE THE FORECAST
AREA THROUGH MUCH OF THE WEEK...ALTHOUGH THE HIGHEST RAIN CHANCES
WILL BE TODAY...MONDAY AND TUESDAY. UPPER LEVEL RIDGING CURRENTLY
OVER THE SOUTHEAST CONUS WILL BE SUPPRESSED BY MID WEEK AS THE
UPPER LOW/TROUGH CURRENTLY OVER THE CENTRAL AND NORTHERN PLAINS
MAKES ITS WAY INTO THE GREAT LAKES REGION AND EVENTUALLY INTO THE
NORTHEAST. THIS WILL ACT TO PUSH A WEAK COLD FRONT SOUTH TO NEAR
THE CENTRAL GULF COAST LATE TUESDAY INTO WEDNESDAY....WITH THIS
BOUNDARY EVENTUALLY BECOME DIFFUSE THE END OF THE WEEK. IN THE
MEANTIME...A MOISTURE LADEN AIRMASS...PRECIPITABLE WATER VALUES
NEAR 2 INCHES...WILL BE ACTED UPON BY WEAK DISTURBANCES ALOFT
MOVING THROUGH LOWER MISSISSIPPI VALLEY AND WESTERN/CENTRAL GULF
COAST REGIONS AROUND THE WESTERN PERIPHERY OF THE UPPER RIDGE.
ALTHOUGH MODELS DUE FORECAST SLIGHTLY DRIER AIR TO WORK INTO THE
REGION OVER THE NEXT COUPLE OF DAYS...PLAN TO KEEP POPS MAINLY IN
THE HIGH END CHANCE TO LOW END LIKELY CATEGORIES THROUGH TUESDAY
AS THE COLD FRONT MAKES ITS WAY SOUTH INTO THE AREA AND THE UPPER
RIDGE IS SUPPRESSED. MORE SIGNIFICANT DRIER AIR IS EXPECTED OVER
THE AREA FOR THE LAST HALF OF THE WEEK...SO LOWER POPS DURING THAT
TIME PERIOD SEEM REASONABLE. A RIDGE WILL BEGIN BUILDING OVER THE
PLAINS AND MISSISSIPPI VALLEY BY THE END OF THE WEEK IN RESPONSE
TO ANOTHER UPPER TROUGH MOVING ACROSS THE WESTERN CONUS. THIS
RIDGE WILL TRANSLATE EASTWARD ACROSS THE EASTERN U.S. NEXT
WEEKEND. 11

&&

.AVIATION...
MAINLY MVFR CEILINGS EARLY THIS MORNING...AND THIS LIKELY TO
CONTINUE THROUGH SUNRISE. WOULD NOT BE SHOCKED TO SEE A BRIEF DIP
INTO THE HIGH END OF IFR AT ONE OR TWO SITES. MODERATE RAIN COULD
AFFECT KGPT FOR SEVERAL MORE HOURS...BUT NO LIGHTNING REPORTED
RECENTLY. LIKELY TO BE ANOTHER SURGE OF SHOWERS AND THUNDERSTORMS BY
LATE MORNING INTO THE EARLY AFTERNOON AT MOST SITES WITH BRIEF WINDS
TO AROUND 25-30 KNOTS. WILL CARRY A TEMPO GROUP FOR THE HIGHEST
THREAT PERIOD...AND WILL ALLOW AMENDMENTS TO TAKE CARE OF THINGS
OUTSIDE THAT WINDOW. 35

&&

.MARINE...
WINDS APPEAR TO BE EASING AT MOST MARINE LOCATIONS AND PLAN TO LET
EXERCISE CAUTION HEADLINES EXPIRE THIS MORNING. WINDS EXPECTED TO
REMAIN BELOW 15 KNOTS THROUGH THE WEEK...AND WIND FIELDS COULD
BECOME SOMEWHAT LIGHT AND VARIABLE AT MIDWEEK AS A WEAK COLD
FRONT MOVES TO NEAR THE COAST BEFORE DISSIPATING. 35

&&

.DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MONITORING RIVERS ALONG MISSISSIPPI COAST FOR FLOODING.

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 RISK SVR AND/OR DIRECT
         TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  86  71  86  69 /  50  20  60  40
BTR  88  73  87  71 /  50  20  60  30
ASD  87  73  86  72 /  50  20  50  30
MSY  87  75  87  73 /  40  20  50  30
GPT  85  75  85  73 /  50  20  30  20
PQL  86  73  86  72 /  50  20  20  20

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR LAZ039-040.

GM...NONE.
MS...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR MSZ077-080>082.

GM...NONE.
&&

HAZARDOUS WEATHER OUTLOOK...UPDATED...
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1130 PM CDT SAT MAY 16 2015

GMZ530-532-534-536-538-550-552-555-557-570-572-575-577-LAZ034>037-
039-040-046>050-056>072-MSZ068>071-077-080>082-171100-
LAKE PONTCHARTRAIN AND LAKE MAUREPAS-MISSISSIPPI SOUND-
LAKE BORGNE-CHANDELEUR SOUND-BRETON SOUND-
COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT
20 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON OUT 20 NM-
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 OUT 20 NM-
COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM
20 TO 60 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON FROM 20 TO 60 NM-
COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER FROM 20 TO 60 NM-
COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO
60 NM-POINTE COUPEE-WEST FELICIANA-EAST FELICIANA-ST. HELENA-
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-NORTHERN TANGIPAHOA-
SOUTHERN TANGIPAHOA-WILKINSON-AMITE-PIKE-WALTHALL-PEARL RIVER-
HANCOCK-HARRISON-JACKSON-
1130 PM CDT SAT MAY 16 2015

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

.DAY ONE...TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVERNIGHT...
ESPECIALLY ACROSS COASTAL MISSISSIPPI. A FLASH FLOOD WATCH IS IN
EFFECT FOR COASTAL MISSISSIPPI UNTIL 7 AM SUNDAY WHERE ADDITIONAL
RAINFALL AMOUNTS OF 2 TO 4 INCHES WILL BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SCATTERED THUNDERSTORMS ARE EXPECTED EACH DAY THROUGH FRIDAY.
ORGANIZED SEVERE THUNDERSTORMS ARE NOT ANTICIPATED AT THIS
TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1107 PM CDT SAT MAY 16 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1055 PM     FLASH FLOOD      10 NNW KILN             30.55N 89.50W
05/16/2015                   HANCOCK            MS   EMERGENCY MNGR

            HWY 43 IN NW HANCOCK COUNTY IMPASSABLE DUE TO WATER OVER
            THE ROADWAY... SEVERAL OTHER ROADS IN THE GENERAL AREA
            ALSO CLOSED

&&

AK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
414 AM CDT SUN MAY 17 2015

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0346 AM     TORNADO          6 SSW INDEPENDENCE      30.56N 90.55W
05/17/2015                   TANGIPAHOA         LA   EMERGENCY MNGR

            EMERGENCY MANAGER REPORTS SEVERAL TRAILERS DAMAGED BY A
            POSSIBLE TORNADO NEAR JOEL MCDONALD ROAD AT WOODHAVEN
            ROAD.

&&