Alert archive / Alabama / Flash Flood Warnings in 2009

Flash Flood Warning 74, NWS Huntsville, AL

September 17, 2009Colbert County, Lauderdale County, Alabama

NWS Huntsville, AL issued this flash flood warning at Sep 17, 2009, 11:29 AM CDT for Colbert County, Lauderdale County, Alabama. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Sep 17, 2009, 11:29 AM CDT (16:29 UTC)
Expired: Sep 17, 2009, 2:30 PM CDT
In force: 3 hr
Issued by: NWS Huntsville, AL
Area: Storm-based polygon
Flood severity: None

Counties Colbert County, AL, Lauderdale County, AL

The radar

The Columbus AFB radar (KGWX), 115 km from the middle of the area, began a volume at 16:31 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

Nashville Metro, TN (KBNA), launched 12:00Z, 4.5 hours before the alert went out and 180 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1026 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 455 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 58 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Huntsville, AL wrote its last area forecast discussion before this flash flood warning went out at Sep 17, 10:31 AM CDT, 58 minutes earlier.

Area forecast discussion, Sep 17, 10:31 AM CDT, 58 minutes before

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Hazardous weather outlook, Sep 17, 8:13 AM CDT, 3 hours 16 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
813 AM CDT THU SEP 17 2009

ALZ001>010-016-TNZ076-096-097-171900-
LAUDERDALE-COLBERT-FRANKLIN AL-LAWRENCE-LIMESTONE-MADISON-MORGAN-
MARSHALL-JACKSON-DEKALB-CULLMAN-MOORE-LINCOLN-FRANKLIN TN-
813 AM CDT THU SEP 17 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH ALABAMA AND PORTIONS
OF SOUTHERN MIDDLE TENNESSEE.

.DAY ONE...TODAY AND TONIGHT...

NUMEROUS SHOWERS...SOME PRODUCING MODERATE TO HEAVY RAINFALL...WILL
CONTINUE TO IMPACT THE TENNESSEE VALLEY AREA THROUGH TONIGHT. DUE TO
THE SLOW MOVEMENT OF THESE SHOWERS...WATER MAY QUICKLY BEGIN TO FILL
STREAMS AND LOW LYING AREAS. PONDING ON ROADWAYS IS ALSO A
POSSIBILITY ESPECIALLY IN AND NEAR THE HEAVIER RAINS. MOTORISTS ARE
URGED TO USE EXTREME CAUTION WHEN TRAVELING ON STREETS WHERE WATER
COVERS THE ROAD.

ISOLATED OR EMBEDDED THUNDERSTORMS CAN NOT BE RULED OUT AS WELL THIS
EVENING AND THROUGH THE OVERNIGHT HOURS. THE STRONGER STORMS WILL BE
CAPABLE OF PRODUCING FREQUENT LIGHTNING AND STRONG GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

A SLOW MOVING STORM SYSTEM OVER SOUTHEAST LOUISIANA WILL GRADUALLY
MOVE TOWARD THE NORTHEAST THROUGH THE END OF THE WORK WEEK. THIS
WILL KEEP THE TENNESSEE VALLEY AREA IN A VERY MOIST ENVIRONMENT
ESPECIALLY AS THE STORM SYSTEM BEGINS TO MOVE ACROSS THE LOWER
MISSISSIPPI VALLEY. PROLONGED HEAVY DOWNPOURS WILL MAINTAIN THE
THREAT FOR LOCALIZED FLOODING ACROSS THE OUTLOOK AREA.

ISOLATED OR SCATTERED THUNDERSTORMS AGAIN CAN NOT BE RULED OUT AS
WELL...ESPECIALLY AS THE STORM SYSTEM BEGINS TO APPROACH THE
TENNESSEE VALLEY THIS WEEKEND. FREQUENT LIGHTNING AND STRONG GUSTY
WINDS REMAIN THE PRIMARY THREATS FROM THESE THUNDERSTORMS.

.SPOTTER CALL TO ACTION STATEMENT...

ACTIVATION OF STORM SPOTTERS AND EMERGENCY MANAGEMENT PERSONNEL IS
NOT ANTICIPATED AT THIS TIME. FIRST RESPONSE AGENCIES ARE ENCOURAGED
TO RELAY ANY REPORTS OF FLASH FLOODING TO THE WEATHER FORECAST
OFFICE IN HUNTSVILLE.

In the hours before

Local storm report, Sep 17, 7:58 AM CDT, 3 hours 31 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
758 AM CDT THU SEP 17 2009

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

0757 AM     FLASH FLOOD      3 N KILLEN              34.90N 87.53W
09/17/2009                   LAUDERDALE         AL   EMERGENCY MNGR

            SEVERAL REPORTS OF FLASH FLOODING AND TRAFFIC ACCIDENTS
            HAVE BEEN RECEIVED IN THE KILLEN AREA AND NORTHWARD
            TOWARD GREEN HILL.

&&

JE

Local storm report, Sep 17, 10:09 AM CDT, 1 hour 20 minutes before

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The office that day

Everything else NWS Huntsville, AL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 16, 7:36 PM CDT	Flash Flood Warning	HUN	Colbert, Franklin, Lauderdale, Lawrence	4 hr
Sep 17, 3:50 AM CDT	Flash Flood Watch	HUN	Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more	6 days
Sep 17, 7:17 AM CDT	Flash Flood Warning	HUN	Lauderdale	5 hr
Sep 17, 7:53 AM CDT	Flash Flood Warning	HUN	Lauderdale	3 hr
Sep 17, 11:48 AM CDT	Flash Flood Warning	HUN	Lauderdale	3 hr
Sep 17, 2:29 PM CDT	Areal Flood Warning	HUN	Lauderdale	4 hr

Nearby

Flash Flood Warnings in Alabama, 2009 Every flash flood warning in 2009

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.