A stationary front over southeast Louisiana provided the focus for the development of several rounds of thunderstorms over southeast Louisiana and southern Mississippi. Torrential rain produced several reports of flash flooding.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LIX wrote it up.
A stationary front over southeast Louisiana provided the focus for the development of several rounds of thunderstorms over southeast Louisiana and southern Mississippi. Torrential rain produced several reports of flash flooding.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS New Orleans, LA wrote its last area forecast discussion before the first event at Apr 12, 6:47 PM CST, 23 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW ORLEANS LA 747 PM CDT SUN APR 12 2015 .SOUNDING DISCUSSION... ...00Z SOUNDING DISCUSSION... THE LATEST SOUNDING WAS TAKEN IN THE IMMEDIATE VICINITY OF A STATIONARY FRONTAL BOUNDARY DRAPED OVER THE FORECAST AREA. THIS SOUNDING INDICATES A FAIRLY HIGH SHEAR ENVIRONMENT...WITH EFFECTIVE STORM RELATIVE HELICITY OF OVER 200 M2/S2 AND A BULK SHEAR VALUE OF 22 M2/S2. CAPE IS DECENT AT AROUND 1000 J/KG AND THE LCL REMAINS VERY LOW AT AROUND 2500 FEET. THESE FACTORS ARE ALSO FAVORABLE FOR CONVECTIVE DEVELOPMENT AND THE FORMATION OF SOME DEEPER UPDRAFTS. GIVEN THESE CONDITIONS...AN ISOLATED WATERSPOUT OR TORNADO COULD OCCUR IN THE VICINITY OF THE LOW LEVEL BOUNDARY. LAPSE RATES ARE FAIRLY WEAK AT LESS THAN 6 DEGREES/KM...BASICALLY FOLLOWING THE MOIST ADIABAT UP TO THE EQUILIBRIUM LEVEL. THESE WEAK LAPSE RATES COMBINED WITH HIGH FREEZING LEVELS WILL KEEP HAIL FORMATION AT BAY. GIVEN THE LACK OF DRY AIR ENTRAINMENT...STRONG STRAIGHT LINE WINDS ARE ALSO LESS LIKELY. HOWEVER...ANY RAINFALL SHOULD BE VERY EFFICIENT...AND RAINFALL RATES OF UP TO 2 INCHES PER HOUR COULD BE POSSIBLE. 32 && .PRELIMINARY POINT TEMPS/POPS... MCB 66 78 66 78 / 70 80 50 80 BTR 68 80 68 80 / 70 80 50 80 ASD 69 80 69 80 / 70 80 50 80 MSY 70 80 70 80 / 60 80 50 70 GPT 70 78 71 78 / 70 80 40 70 PQL 70 79 71 81 / 70 80 40 70 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR LAZ046-049-056>070. GM...NONE. MS...NONE. GM...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE NEW ORLEANS LA 535 PM CDT SUN APR 12 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>082-131400- 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- 535 PM CDT SUN APR 12 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST LOUISIANA...SOUTH MISSISSIPPI AND THE ADJACENT COASTAL WATERS. .DAY ONE...TONIGHT NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED TONIGHT. SOME OF THE SHOWERS AND THUNDERSTORMS COULD PRODUCE LOCALLY HEAVY RAINFALL. A FLASH FLOOD WATCH IS IN EFFECT FOR THOSE AREAS OF SOUTHEAST LOUISIANA TO THE SOUTH...SOUTHWEST AND WEST OF LAKE PONTCHARTRAIN...INCLUDING THE NEW ORLEANS METRO AREA. ALTHOUGH SEVERE WEATHER IS NOT ANTICIPATED...A FEW STORMS COULD BE STRONG AND PRODUCE FREQUENT LIGHTNING AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A FLASH FLOOD WATCH WILL REMAIN IN EFFECT THROUGH MONDAY. NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS MONDAY MAY RESULT IN AREAS OF HEAVY RAINFALL WHICH COULD LEAD TO FLASH FLOODING. OTHERWISE...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CAN BE EXPECTED EACH DAY DURING THE REMAINDER OF THE WEEK WITH LOCALLY HEAVY RAINFALL POSSIBLE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
517 PM CDT SUN APR 12 2015
MSZ080-081-122245-
HANCOCK-HARRISON-
517 PM CDT SUN APR 12 2015
...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN HARRISON AND
SOUTHEASTERN HANCOCK COUNTIES...
AT 516 PM CDT...A STRONG THUNDERSTORM WAS JUST SOUTH OF
WAVELAND...MOVING NORTHEAST AT 20 MPH.
WINDS IN EXCESS OF 40 MPH ARE POSSIBLE WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE... LONG BEACH...BAY ST.
LOUIS...WAVELAND...AND DIAMONDHEAD.
LAT...LON 3035 8912 3030 8928 3031 8929 3033 8929
3036 8928 3036 8931 3037 8931 3037 8935
3033 8938 3034 8934 3031 8933 3026 8939
3026 8942 3023 8942 3022 8944 3023 8947
3053 8935 3040 8908
TIME...MOT...LOC 2216Z 208DEG 16KT 3026 8935
11SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
620 PM CDT SUN APR 12 2015
MSZ081-082-122345-
JACKSON-HARRISON-
620 PM CDT SUN APR 12 2015
...A STRONG THUNDERSTORM WILL AFFECT EASTERN HARRISON AND
SOUTHWESTERN JACKSON COUNTIES...
AT 619 PM CDT...A STRONG THUNDERSTORM OVER MISSISSIPPI SOUND SOUTH
OF BILOXI...MOVING NORTH NORTHEAST AT 15 MPH.
WINDS IN EXCESS OF 40 MPH ARE POSSIBLE WITH THIS STORM.
LOCATIONS IMPACTED INCLUDE... GULFPORT...BILOXI...OCEAN
SPRINGS...ST. MARTIN...AND D'IBERVILLE.
LAT...LON 3039 8880 3038 8880 3043 8885 3043 8893
3042 8895 3043 8899 3041 8899 3042 8891
3041 8887 3036 8882 3039 8887 3039 8897
3037 8906 3061 8901 3052 8871
TIME...MOT...LOC 2319Z 198DEG 15KT 3036 8895
11The Mobile radar (KMOB), 68 km away, was scanning. The volume nearest the first event began at 01:09 UTC.
6 flash flood. Local standard time, as filed.
High water was reported on US Highway 90 in Gulfport at 810 pm.
Significant street flooding was reported in the Gulfport and Biloxi areas. Water was covering portions of US Highway 90 with water rescues in progress.
The Emergency Manager reported flooding of US Highway 11 in the Ozona area.
The Emergency Manager reported widespread street and roadway flooding across Hancock County. Some roads were being evaluated for potential closure.
US Highway 90 was reported impassable due to flood waters near Iberville Drive.
The Picayune Police Department reported several roads across the city were flooded and impassable.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Mississippi in 2015Every state in 2015This day in weather historyWarnings in Mississippi, April 2015
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 563951, 563954, 563988, 563989, 563999, 564001.