Alert archive / Louisiana / Flash Flood Warnings in 2010

Flash Flood Warning 15, NWS New Orleans, LA

July 25, 2010Washington Parish, Louisiana; Walthall County, Mississippi

NWS New Orleans, LA issued this flash flood warning at Jul 25, 2010, 8:27 AM CDT for Washington Parish, Louisiana; Walthall County, Mississippi. It was in force for 69 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 25, 2010, 8:27 AM CDT (13:27 UTC)
Expired
Jul 25, 2010, 9:36 AM CDT
In force
69 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

Counties Washington Parish, LA, Walthall County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 1.5 hours before the alert went out and 91 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Slidell Radar S, LA at 12:00Z on 2010-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3379 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 12:00Z on 2010-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 178 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
3379 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
457 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
178 m²/s²
0-3 km storm-relative helicity
199 m²/s²
Significant tornado parameter
2.4
Supercell composite
12.6

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Jul 25, 7:59 AM CDT, 28 minutes earlier.

Area forecast discussion, Jul 25, 7:59 AM CDT, 28 minutes before
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Hazardous weather outlook, Jul 25, 5:41 AM CDT, 2 hours 46 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
541 AM CDT SUN JUL 25 2010

GMZ530-532-534-536-538-550-552-555-557-570-572-575-577-LAZ034>040-
046>050-056>070-MSZ068>071-077-080>082-261045-
LAKE PONTCHARTRAIN AND LAKE MAUREPAS-MISSISSIPPI SOUND-
LAKE BORGNE-CHANDELEUR SOUND-BRETON SOUND-
COASTAL WATERS FROM THE 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 THE 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-
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-
541 AM CDT SUN JUL 25 2010

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

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SCATTERED TO NUMEROUS THUNDERSTORMS WILL CONTINUE THIS MORNING
AND WILL LIKELY PERSIST INTO THE AFTERNOON OVER PORTIONS OF THE
AREA AS THE REMNANTS OF BONNIE MOVE INLAND. THE MAIN THREATS FROM
THUNDERSTORMS TODAY WILL BE INTENSE CLOUD TO GROUND
LIGHTNING...WIND GUSTS TO 40 MPH...AND LOCALLY VERY HEAVY RAINFALL
AMOUNTS OF ONE TO THREE INCHES IN A SHORT PERIOD OF TIME THAT
COULD RESULT IN MINOR FLOODING OF STREETS AND LOW LYING AREAS. A
FEW OF THE STRONGER THUNDERSTORMS THIS MORNING COULD ALSO SPAWN
ISOLATED TORNADOES AND WATERSPOUTS.

TIDES...
A COASTAL FLOOD ADVISORY HAS BEEN POSTED FOR THE SOUTHEAST AND
EAST FACING SHORES FROM NEAR BAY ST. LOUIS TO THE EAST BANK OF
PLAQUEMINES PARISH. TIDES WERE RUNNING TWO FEET ABOVE NORMAL ALONG
THE COAST OF HANCOCK COUNTY AND NEAR LAKE BORGNE. TIDES ARE LIKELY
TO REMAIN ONE AND ONE HALF TO TWO FEET ABOVE NORMAL TODAY WHICH
WILL RESULT IN MINOR FLOODING OF LOW LYING AREAS NEAR AND DURING
HIGH TIDE LATER THIS MORNING AND THIS AFTERNOON.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THUNDERSTORMS....
TROPICAL MOISTURE WILL REMAIN IN PLACE MONDAY THROUGH WEDNESDAY
LEADING TO SCATTERED...MAINLY DIURNALLY DRIVEN THUNDERSTORMS
THROUGH THE PERIOD. A DEEP LAYER OF HIGH PRESSURE WILL BUILD OVER
THE AREA THURSDAY THROUGH SATURDAY WHICH WILL RESULT IN ONLY
ISOLATED MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS. THE STRONGER
THUNDERSTORMS EACH DAY MAY PRODUCE FREQUENT LIGHTNING
STRIKES...GUSTY WINDS...AND LOCALLY HEAVY RAINFALL.

DRIER CONDITIONS THURSDAY THROUGH SATURDAY WILL LEAD TO HOTTER
TEMPERATURES WITH HIGHS EXPECTED TO RETURN TO THE MID 90S OVER
MOST OF THE AREA. AFTERNOON HEAT INDICES WILL LIKELY RISE INTO
THE 105 TO 110 DEGREE RANGE...AND HEAT ADVISORIES MAY BE
REQUIRED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

22/TD

In the hours before

Special weather statement, Jul 25, 6:05 AM CDT, 2 hours 22 minutes before
MSZ077-080-081-251200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
605 AM CDT SUN JUL 25 2010

...CLUSTER OF STRONG THUNDERSTORMS MOVING NORTH AFFECTING PEARL RIVER
COUNTY...HANCOCK COUNTY...HARRISON COUNTY...

AT 600 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
CLUSTER OF STRONG THUNDERSTORMS 12 MILES NORTH OF DIAMONDHEAD...OR
ABOUT 22 MILES SOUTHEAST OF POPLARVILLE...MOVING NORTH AT 15 MPH.

THE CLUSTER OF STRONG THUNDERSTORMS WILL AFFECT AREAS IN AND
AROUND...POPLARVILLE

THE PRIMARY THREATS FROM THESE STORMS ARE 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 THESE STORMS
HAVE PASSED.

FREQUENT LIGHTNING IS OCCURRING WITH THESE STORMS. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.
Special weather statement, Jul 25, 6:10 AM CDT, 2 hours 17 minutes before
LAZ038>040-251215-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
610 AM CDT SUN JUL 25 2010

...LINE OF STRONG THUNDERSTORMS MOVING NORTHWEST AFFECTING WASHINGTON
PARISH...TANGIPAHOA PARISH...ST. TAMMANY PARISH...

AT 606 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM 9 MILES
SOUTH OF FRANKLINTON TO 7 MILES EAST OF HAMMOND...MOVING NORTHWEST AT
5 MPH.

THE LINE OF STRONG THUNDERSTORMS WILL AFFECT AREAS IN AND AROUND...
HAMMOND...WILMER...TICKFAW AND INDEPENDENCE

THE PRIMARY THREAT FROM THESE STORMS IS FREQUENT LIGHTNING. SEEK
SHELTER IN A SAFE HOME OR BUILDING UNTIL THESE STORMS HAVE PASSED.

FREQUENT LIGHTNING IS OCCURRING WITH THESE STORMS. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.
Special weather statement, Jul 25, 6:28 AM CDT, 1 hour 59 minutes before
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Special weather statement, Jul 25, 6:31 AM CDT, 1 hour 56 minutes before
LAZ060-251230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
631 AM CDT SUN JUL 25 2010

...CLUSTER OF STRONG THUNDERSTORMS NEARLY STATIONARY AFFECTING ST.
CHARLES PARISH...

AT 630 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
CLUSTER OF STRONG THUNDERSTORMS 6 MILES NORTHEAST OF HAHNVILLE...OR
ABOUT 4 MILES NORTHEAST OF NEW SARPY. THE THUNDERSTORMS WERE NEARLY
STATIONARY.

THE CLUSTER OF STRONG THUNDERSTORMS WILL AFFECT MAINLY RURAL AREAS OF
THE INDICATED PARISH.

THE PRIMARY THREAT FROM THESE STORMS IS FREQUENT LIGHTNING. SEEK
SHELTER IN A SAFE HOME OR BUILDING UNTIL THESE STORMS HAVE PASSED.

THESE STORMS COULD PRODUCE RAINFALL AMOUNTS OF ONE TO TWO INCHES IN A
SHORT PERIOD OF TIME...RESULTING IN PONDING OF WATER AROUND LOW LYING
ROADWAYS. REMEMBER...DO NOT DRIVE YOUR VEHICLE INTO WATER COVERED
ROADWAYS. THE DEPTH MAY BE TOO GREAT TO ALLOW A SAFE CROSSING.

FREQUENT LIGHTNING IS OCCURRING WITH THESE STORMS. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.
Special weather statement, Jul 25, 7:02 AM CDT, 1 hour 25 minutes before
LAZ034-035-251300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
702 AM CDT SUN JUL 25 2010

...STRONG THUNDERSTORM MOVING NORTHWEST AFFECTING POINTE COUPEE
PARISH...WEST FELICIANA PARISH...

AT 658 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 6 MILES SOUTHWEST OF NEW ROADS...MOVING
NORTHWEST AT 20 MPH.

THE STRONG THUNDERSTORM WILL AFFECT AREAS IN AND AROUND...NEW
ROADS...MORGANZA...BATCHELOR AND LETTSWORTH

THE PRIMARY THREATS FROM THIS STORM ARE FREQUENT LIGHTNING AND 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.

FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

95/DM
Special weather statement, Jul 25, 7:48 AM CDT, 39 minutes before
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The office that day

Everything else NWS New Orleans, LA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 25, 3:31 AM CDTCoastal Flood AdvisoryLIXSaint Bernard7 hr
Jul 25, 4:59 AM CDTTornado WarningLIXPlaquemines21 min
Jul 25, 5:08 AM CDTSevere Thunderstorm WarningLIXLafourche, Saint Charles, Saint John the Baptist52 min
Jul 25, 5:28 AM CDTSevere Thunderstorm WarningLIXAscension, Assumption, Livingston, Saint James, Saint John the Baptist, Tangipahoa62 min
Jul 25, 5:41 AM CDTSevere Thunderstorm WarningLIXJefferson, Orleans, Plaquemines, Saint Charles44 min
Jul 25, 6:00 AM CDTSpecial Marine WarningLIX60 min
Jul 25, 6:21 AM CDTSevere Thunderstorm WarningLIXIberville, West Baton Rouge54 min
Jul 25, 7:15 AM CDTTornado WarningLIXWashington30 min
Jul 25, 7:33 AM CDTFlash Flood WarningLIXEast Baton Rouge, Iberville, West Baton Rouge3 hr
Jul 25, 3:22 PM CDTHeat AdvisoryLIXAssumption, East Baton Rouge, East Feliciana, Iberville, Pointe Coupee, Saint Bernard and 6 more28 hr

Nearby

Flash Flood Warnings in Louisiana, 2010Flash Flood Warnings in Mississippi, 2010Every flash flood warning in 2010

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.