Scattered strong to severe thunderstorms developed in a moist and very unstable airmass.
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.
Scattered strong to severe thunderstorms developed in a moist and very unstable airmass.
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 May 16, 10:25 AM CST, 3 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW ORLEANS LA 1125 AM CDT SAT MAY 16 2009 .UPDATE... ...AVIATION 18Z TAF ISSUANCE... CONVECTION IGNITING ALONG LAKE AND SEA BREEZES AND WILL LIKELY IMPACT KGPT AND KMSY BEFORE 20Z. SCATTERED SHOWERS AND THUNDERSTORMS ANTICIPATED AT KBTR AND KMCB BETWEEN 20Z AND 24Z. RADAR INDICATES DOWNBURST SIGNATURES UNDER TEH STORMS MOSTLY IN THE 20KT RANGE BUT MAY BE AS STRONG AS 40 KT. SPS ISSUED FOR A PARTICULAR DOWNBURST INDICATED ON TMSY RADAR NEAR HAHNVILLE ON THE W RUNWAY APPROACH. .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && 24/RR
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE NEW ORLEANS LA 1100 AM CDT SAT MAY 16 2009 GMZ530-550-555-570-575-LAZ034>040-046>050-056>070-MSZ068>071-077- 080>082-171600- 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- 1100 AM CDT SAT MAY 16 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 SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE AFTERNOON AND EVENING HOURS. ISOLATED STORMS COULD BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NOT EXPECTED. THESE SHOWERS AND THUNDERSTORMS WILL BE VERY SLOW MOVING AND CAPABLE OF PRODUCING VERY HEAVY RAIN IN A FEW LOCATIONS. MINOR TO MODERATE RIVER FLOODING ON THE MISSISSIPPI RIVER WILL CONTINUE AT RED RIVER LANDING...BATON ROUGE...AND DONALDSONVILLE. MINOR FLOODING WILL CONTINUE ON THE ATCHAFALAYA RIVER AT MORGAN CITY. PLEASE REFER TO THE LATEST RIVER FLOOD STATEMENTS FOR DETAILS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY A COLD FRONT WILL MOVE INTO THE AREA ON SUNDAY. AHEAD OF THE FRONT...STRONG THUNDERSTORMS WILL BE POSSIBLE...MAINLY DURING THE MORNING AND EARLY AFTERNOON HOURS. THE STRONGEST THUNDERSTORMS WILL BE CAPABLE OF PRODUCING DAMAGING WINDS AND HAIL. NORTH TO NORTHEAST WINDS BEHIND THE FRONT MAY PRODUCE SMALL CRAFT CONDITIONS AS EARLY AS SUNDAY NIGHT OVER THE TIDAL LAKES AND COASTAL WATERS. THESE CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST TUESDAY. MINOR TO MODERATE RIVER FLOODING ON THE MISSISSIPPI RIVER WILL CONTINUE AT RED RIVER LANDING...BATON ROUGE...AND DONALDSONVILLE. MINOR FLOODING WILL CONTINUE ON THE ATCHAFALAYA RIVER AT MORGAN CITY. PLEASE REFER TO THE LATEST RIVER FLOOD STATEMENTS FOR DETAILS. LOW PRESSURE IS EXPECTED TO DEVELOP OVER SOME PORTION OF THE CENTRAL OR EASTERN GULF OF MEXICO TOWARD THE END OF THE WEEK. DEPENDING ON THE LOCATION AND STRENGTH OF THE LOW...SMALL CRAFT ADVISORY CONDITIONS MAY RETURN TO THE LOCAL COASTAL WATERS. LATER FORECASTS WILL REFINE THE DETAILS OF THE WEATHER ASSOCIATED WITH THIS SYSTEM. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
LAZ058-060-061-161700- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE NEW ORLEANS LA 1109 AM CDT SAT MAY 16 2009 ...STRONG THUNDERSTORM MOVING SOUTHEAST AFFECTING ST. JOHN THE BAPTIST PARISH...ST. CHARLES PARISH...JEFFERSON PARISH... AT 1108 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM NEAR HAHNVILLE...OR ABOUT 3 MILES NORTH OF NORCO...MOVING SOUTHEAST AT 5 MPH. THIS STORM IS PRODUCING A DOWNBURST OF STRONG WIND GUSTS 25 TO 40 MPH NEAR HAHNVILLE. THE STRONG THUNDERSTORM WILL BE NEAR... NORCO BY 1135 AM... HAHNVILLE BY 1155 AM... NEW SARPY...DESTREHAN...7 MILES WEST OF KENNER AND 7 MILES WEST OF NEW ORLEANS ARMSTRONG AIRPORT BY NOON... THE PRIMARY THREAT FROM THIS STORM IS WIND GUSTS TO NEAR 40 MPH... WHICH COULD DOWN TREE LIMBS AND BLOW AROUND UNSECURED SMALL OBJECTS. SEEK SHELTER IN A SAFE HOME OR BUILDING UNTIL THIS STORM HAS PASSED. 24/RR
LAZ034-035-046-161800- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE NEW ORLEANS LA 1205 PM CDT SAT MAY 16 2009 ...CLUSTER OF STRONG THUNDERSTORMS MOVING NORTH AFFECTING IBERVILLE PARISH...POINTE COUPEE PARISH...WEST FELICIANA PARISH... AT 1203 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A CLUSTER OF STRONG THUNDERSTORMS 13 MILES EAST OF KROTZ SPRINGS...OR OVER MARINGOUIN...MOVING NORTH AT 15 MPH. THE CLUSTER OF STRONG THUNDERSTORMS WILL BE NEAR... LIVONIA BY 1225 PM... LOTTIE BY 1230 PM... MORGANZA AND 7 MILES WEST OF NEW ROADS BY 100 PM... THE PRIMARY THREATS FROM THESE STORMS ARE PEA TO MARBLE SIZE HAIL AND WIND GUSTS 40 TO 50 MPH...WHICH COULD DOWN TREE LIMBS AND BLOW AROUND UNSECURED SMALL OBJECTS. SEEK SHELTER IN A SAFE HOME OR BUILDING UNTIL THESE STORMS HAVE PASSED. 24/RR
MSZ080-161900- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE NEW ORLEANS LA 128 PM CDT SAT MAY 16 2009 ...STRONG THUNDERSTORM MOVING NORTHEAST AFFECTING HANCOCK COUNTY... AT 127 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 12 MILES EAST OF PICAYUNE...MOVING NORTHEAST AT 10 MPH. THE STRONG THUNDERSTORM WILL BE NEAR... RURAL HANCOCK COUNTY AT 140 PM THE PRIMARY THREATS FROM THIS STORM ARE PEA TO MARBLE SIZE HAIL AND WIND GUSTS 40 TO 50 MPH...WHICH COULD DOWN TREE LIMBS AND BLOW AROUND UNSECURED SMALL OBJECTS. SEEK SHELTER IN A SAFE HOME OR BUILDING UNTIL THIS STORM HAS PASSED. 24/RR
The national radar mosaic for the moment the first event began.
4 hail, 1 thunderstorm wind, 1 funnel cloud, 1 tornado. Local standard time, as filed.
Thunderstorm winds caused minor damage to roofs, carports, and porches in the Gentilly area.
A funnel cloud was observed near the Naval Air Station in Belle Chasse.
Nickel size hail was reported along Highway 442 between Magnolia and Starns.
Quarter size hail was reported on Highway 445 in Husser.
A National Weather Service storm damage survey indicated that a waterspout moved onshore from Lake Pontchartrain as a weak tornado before dissipating. Intermittent property damage occurred to a few houses and businesses from near the lakefront and Severn Avenue to a few blocks south of West Esplanade and Hessemmer Avenue. Damage occurred to trees, fences, and a few roofs.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Louisiana in 2009Every state in 2009This day in weather historyThe tornado archive for Louisiana, 2009Warnings in Louisiana, May 2009
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: 175965, 175966, 175967, 175968, 175969, 175972, 175970.