Alert archive / Mississippi / Flash Flood Watches in 2011

Flash Flood Watch 12, NWS Jackson, MS

May 12, 20119 counties in Mississippi; 4 parishes in Louisiana; Chicot County, Arkansas

NWS Jackson, MS issued this flash flood watch at May 12, 2011, 4:00 PM CDT for 9 counties in Mississippi; 4 parishes in Louisiana; Chicot County, Arkansas. It took effect at May 12, 2011, 7:00 PM CDT. It was in force for 20 hr.

The area

The counties it named.

The facts

Issued
May 12, 2011, 4:00 PM CDT (21:00 UTC)
In effect from
May 12, 2011, 7:00 PM CDT
Expired
May 13, 2011, 3:24 PM CDT
In force
20 hr
Issued by
NWS Jackson, MS
Flood severity
None

Counties Chicot County, AR, Concordia Parish, LA, East Carroll Parish, LA, Madison Parish, LA, Tensas Parish, LA, Bolivar County, MS, Claiborne County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 101 km from the middle of the area, began a volume at 20:59 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 9.0 hours before the alert went out and 264 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, Shreveport, LA at 12:00Z on 2011-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 314 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, Shreveport, LA at 12:00Z on 2011-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 258 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
314 J/kg
Mixed-layer CIN
-238 J/kg
Mixed-layer LCL
921 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
258 m²/s²
0-3 km storm-relative helicity
361 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Jackson, MS wrote its last area forecast discussion before this flash flood watch went out at May 12, 10:10 AM CDT, 5 hours 50 minutes earlier.

Area forecast discussion, May 12, 10:10 AM CDT, 5 hours 50 minutes before
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Hazardous weather outlook, May 12, 3:47 PM CDT, 13 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
347 PM CDT THU MAY 12 2011

MSZ026>033-037>039-043>046-048>066-072>074-132100-
GRENADA-CARROLL-MONTGOMERY-WEBSTER-CLAY-LOWNDES-CHOCTAW-OKTIBBEHA-
ATTALA-WINSTON-NOXUBEE-MADISON MS-LEAKE-NESHOBA-KEMPER-HINDS-
RANKIN-SCOTT-NEWTON-LAUDERDALE-CLAIBORNE-COPIAH-SIMPSON-SMITH-
JASPER-CLARKE-JEFFERSON-ADAMS-FRANKLIN MS-LINCOLN-LAWRENCE-
JEFFERSON DAVIS-COVINGTON-JONES-MARION-LAMAR-FORREST-
347 PM CDT THU MAY 12 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MISSISSIPPI.

.DAY ONE...TONIGHT THROUGH FRIDAY NIGHT

STRONG TO SEVERE THUNDERSTORMS CAPABLE OF QUARTER SIZED HAIL AND WIND
GUSTS TO 60 MPH WILL BE POSSIBLE FRIDAY INTO FRIDAY NIGHT. THIS
ACTIVITY WILL DEVELOP FRIDAY AHEAD OF A SLOW MOVING COLD FRONT THAT
WILL NOT MOVE ACROSS THE AREA UNTIL LATE FRIDAY NIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL IN SUPPORT OF SEVERE WEATHER
OPERATIONS...MAY BE NEEDED FRIDAY INTO FRIDAY NIGHT.

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025-034>036-
040>042-047-132100-
ASHLEY-CHICOT-MOREHOUSE-WEST CARROLL-EAST CARROLL-RICHLAND-
MADISON LA-FRANKLIN LA-CATAHOULA-TENSAS-CONCORDIA-BOLIVAR-
SUNFLOWER-LEFLORE-WASHINGTON-HUMPHREYS-HOLMES-ISSAQUENA-SHARKEY-
YAZOO-WARREN-
347 PM CDT THU MAY 12 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
MISSISSIPPI...NORTHEAST LOUISIANA...AND EXTREME SOUTHEAST ARKANSAS.

.DAY ONE...TONIGHT THROUGH FRIDAY NIGHT

A FEW STRONG TO SEVERE THUNDERSTORMS CAPABLE OF QUARTER SIZED HAIL
AND WIND GUSTS TO 60 MPH WILL BE POSSIBLE THIS EVENING AND AGAIN FRIDAY
INTO FRIDAY NIGHT. THIS ACTIVITY WILL DEVELOP WELL AHEAD OF A SLOW MOVING
COLD FRONT THAT WILL MOVE ACROSS THE AREA FRIDAY NIGHT. DUE TO THE
CURRENT FLOODING OCCURRING ALONG THE MISSISSIPPI RIVER AND BACKWATER
AREAS...FLASH FLOODING WILL BE POSSIBLE WITH ANY THUNDERSTORM
DROPPING LOCALLY HEAVY RAIN. A FLASH FLOOD WATCH IS IN EFFECT THROUGH
FRIDAY EVENING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL IN SUPPORT OF SEVERE WEATHER
OPERATIONS...MAY BE NEEDED IN THE WEST THIS EVENING AND THE WHOLE AREA
FRIDAY INTO FRIDAY NIGHT.

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/JAN.

22

In the hours before

Local storm report, May 12, 10:24 AM CDT, 5 hours 36 minutes before
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Nearby

Flash Flood Watches in Mississippi, 2011Flash Flood Watches in Louisiana, 2011Flash Flood Watches in Arkansas, 2011Every flash flood watch in 2011

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; radar from the NEXRAD Level II archive.