Alert archive / Alabama / Areal Flood Warnings in 2021

Areal Flood Warning 9, NWS Huntsville, AL

March 18, 20216 counties in Alabama; Franklin County, Tennessee

NWS Huntsville, AL issued this areal flood warning at Mar 18, 2021, 1:30 AM CDT for 6 counties in Alabama; Franklin County, Tennessee. It was in force for 8 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: Mar 18, 2021, 1:30 AM CDT (06:30 UTC)
Expired: Mar 18, 2021, 9:00 AM CDT
In force: 8 hr
Issued by: NWS Huntsville, AL
Area: Storm-based polygon
Flood severity: None

Counties Cullman County, AL, DeKalb County, AL, Jackson County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Franklin County, TN

The radar

The Northeast Alabama radar (KHTX), 45 km from the middle of the area, began a volume at 06:34 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

Birmingham, AL (KBMX), launched 00:00Z, 6.5 hours before the alert went out and 161 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: 188 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 669 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 336 m²/s²
0-3 km storm-relative helicity: 465 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal 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 areal flood warning went out at Mar 18, 12:00 AM CDT, 1 hour 30 minutes earlier.

Area forecast discussion, Mar 18, 12:00 AM CDT, 1 hour 30 minutes before

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Hazardous weather outlook, Mar 17, 10:53 PM CDT, 2 hours 37 minutes before

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In the hours before

Local storm report, Mar 17, 11:22 PM CDT, 2 hours 8 minutes before

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Local storm report, Mar 18, 12:15 AM CDT, 1 hour 15 minutes before

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Local storm report, Mar 18, 12:17 AM CDT, 1 hour 13 minutes before

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Local storm report, Mar 18, 12:18 AM CDT, 1 hour 12 minutes before

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Local storm report, Mar 18, 12:20 AM CDT, 1 hour 10 minutes before

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Local storm report, Mar 18, 1:18 AM CDT, 12 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
Mar 17, 7:40 PM CDT	Areal Flood Warning	HUN	Colbert, Lauderdale	6 hr
Mar 17, 7:54 PM CDT	Special Weather Statement	HUN	Colbert, Lauderdale	36 min
Mar 17, 8:16 PM CDT	Areal Flood Warning	HUN	DeKalb, Jackson, Madison, Marshall, Morgan	6 hr
Mar 17, 8:17 PM CDT	Special Weather Statement	HUN	Colbert, Franklin	43 min
Mar 17, 8:26 PM CDT	Special Weather Statement	HUN	Lauderdale	34 min
Mar 17, 8:47 PM CDT	Areal Flood Warning	HUN	Madison	11 hr
Mar 17, 8:50 PM CDT	Special Weather Statement	HUN	Colbert, Lauderdale, Lawrence	25 min
Mar 17, 9:06 PM CDT	River Flood Warning	HUN	Lawrence	24 hr
Mar 17, 9:07 PM CDT	Flash Flood Warning	HUN	Colbert, Lauderdale	3 hr
Mar 17, 9:14 PM CDT	Special Weather Statement	HUN	Cullman	31 min
Mar 17, 9:19 PM CDT	Flash Flood Warning	HUN	Jackson, Madison, Marshall, Morgan	3 hr
Mar 17, 9:34 PM CDT	Areal Flood Warning	HUN	DeKalb	6 hr
Mar 17, 9:45 PM CDT	Special Weather Statement	HUN	Marshall, Morgan	30 min
Mar 17, 10:09 PM CDT	Areal Flood Warning	HUN	Cullman, Madison, Morgan	6 hr
Mar 17, 10:13 PM CDT	Special Weather Statement	HUN	DeKalb, Jackson	47 min
Mar 17, 10:44 PM CDT	Tornado Warning	HUN	DeKalb	13 min
Mar 17, 11:03 PM CDT	Special Weather Statement	HUN	DeKalb	27 min
Mar 17, 11:10 PM CDT	Flash Flood Warning Considerable damage threat	HUN	Jackson, Marshall	4 hr
Mar 18, 12:03 AM CDT	Areal Flood Warning	HUN	Marshall	117 min
Mar 18, 8:35 AM CDT	Areal Flood Warning	HUN	Madison	2 hr
Mar 18, 10:15 AM CDT	River Flood Warning	HUN	Jackson, Madison, Marshall	67 hr
Mar 18, 10:45 AM CDT	River Flood Warning	HUN	Colbert, Lauderdale	4 days

Nearby

Areal Flood Warnings in Alabama, 2021 Areal Flood Warnings in Tennessee, 2021 Every areal flood warning in 2021

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.