Alert archive / Alabama / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 101, NWS Huntsville, AL

August 27, 2020Limestone County, Madison County, Alabama

NWS Huntsville, AL issued this severe thunderstorm warning at Aug 27, 2020, 3:21 PM CDT for Limestone County, Madison County, Alabama. It was in force for 24 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: Aug 27, 2020, 3:21 PM CDT (20:21 UTC)
Expired: Aug 27, 2020, 3:45 PM CDT
In force: 24 min
Issued by: NWS Huntsville, AL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Limestone County, AL, Madison County, AL

The radar

The Northeast Alabama radar (KHTX), 64 km from the middle of the area, began a volume at 20:23 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, 8.4 hours before the alert went out and 150 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: 1006 J/kg
Mixed-layer CIN: -46 J/kg
Mixed-layer LCL: 1007 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 35 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 severe thunderstorm 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 severe thunderstorm warning went out at Aug 27, 12:59 PM CDT, 2 hours 22 minutes earlier.

Area forecast discussion, Aug 27, 12:59 PM CDT, 2 hours 22 minutes before

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Hazardous weather outlook, Aug 27, 3:43 AM CDT, 11 hours 38 minutes before

Hazardous Weather Outlook
National Weather Service Huntsville AL
343 AM CDT Thu Aug 27 2020

ALZ001>010-016-TNZ076-096-097-272345-
Lauderdale-Colbert-Franklin AL-Lawrence-Limestone-Madison-Morgan-
Marshall-Jackson-DeKalb-Cullman-Moore-Lincoln-Franklin TN-
343 AM CDT Thu Aug 27 2020

This Hazardous Weather Outlook is for north Alabama and portions of
southern middle Tennessee.

.DAY ONE...Today and Tonight...

Isolated to scattered thunderstorms will be possible today, mainly
during the afternoon and early evening hours.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday...

Thunderstorm coverage will increase Friday into Saturday, as the
remnants of Hurricane Laura move eastward across the Mid South and
lower Ohio Valley areas. A few storms may be capable of producing
locally heavy rainfall and strong gusty winds. A few tornadoes may
also be possible late Friday.

Scattered storms will remain in the forecast Sunday and Monday, as a
weak frontal boundary settles into the region from the north.

.SPOTTER INFORMATION STATEMENT...

Formal activation of storm spotters and emergency management
personnel is not anticipated at this time. However, timely reports
of flooding will be greatly appreciated.

Please relay any information about observed severe weather to the
NWS while following all local, state, and CDC guidelines.

In the hours before

Special weather statement, Aug 27, 3:16 PM CDT, 5 minutes before

Special Weather Statement
National Weather Service Huntsville AL
316 PM CDT Thu Aug 27 2020

ALZ003-272100-
Franklin AL-
316 PM CDT Thu Aug 27 2020

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN FRANKLIN COUNTY UNTIL 400
PM CDT...

At 315 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles north of Weston, moving north at 30 mph.

Winds in excess of 45 mph will be possible with this storm.

Locations impacted include...
Red Bay, Vina, Atwood, Dempsey, Little Bear Creek Reservoir,
Halltown, Pleasant Site and Cedar Creek Reservoir.

LAT...LON 3434 8817 3453 8815 3456 8793 3431 8794
      3432 8817 3434 8818
TIME...MOT...LOC 2015Z 172DEG 26KT 3429 8803

KTW

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 27, 3:16 PM CDT	Special Weather Statement	HUN	Franklin	44 min
Aug 27, 3:30 PM CDT	Special Weather Statement	HUN	Lawrence	30 min
Aug 27, 3:36 PM CDT	Special Weather Statement	HUN	Franklin	24 min
Aug 27, 3:40 PM CDT	Special Weather Statement	HUN	Lawrence	50 min
Aug 27, 3:53 PM CDT	Special Weather Statement	HUN	DeKalb	37 min
Aug 27, 3:59 PM CDT	Special Weather Statement	HUN	Colbert, Lauderdale	31 min
Aug 27, 4:11 PM CDT	Special Weather Statement	HUN	DeKalb, Jackson	49 min
Aug 27, 4:18 PM CDT	Severe Thunderstorm Warning	HUN	DeKalb, Jackson	27 min
Aug 27, 4:27 PM CDT	Special Weather Statement	HUN	Limestone	33 min
Aug 27, 4:30 PM CDT	Special Weather Statement	HUN	Lauderdale	30 min
Aug 27, 4:58 PM CDT	Special Weather Statement	HUN	Jackson	47 min
Aug 27, 5:04 PM CDT	Severe Thunderstorm Warning	HUN	Jackson	26 min
Aug 27, 6:12 PM CDT	Special Weather Statement	HUN	Madison	33 min
Aug 27, 6:26 PM CDT	Special Weather Statement	HUN	Madison	49 min
Aug 27, 5:32 PM CDT	Special Weather Statement	HUN	Franklin	28 min
Aug 27, 5:52 PM CDT	Special Weather Statement	HUN	Franklin	38 min

Nearby

Severe Thunderstorm Warnings in Alabama, 2020 Every severe thunderstorm warning in 2020

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.