Alert archive / Alabama / Special Weather Statements in 2021

Special Weather Statement, NWS Huntsville, AL

July 18, 2021Limestone County, Alabama

NWS Huntsville, AL issued this special weather statement at Jul 18, 2021, 7:20 PM CDT for Limestone County, Alabama. It was in force for 40 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 18, 2021, 7:20 PM CDT (00:20 UTC)
Expired
Jul 18, 2021, 8:00 PM CDT
In force
40 min
Issued by
NWS Huntsville, AL

County Limestone County, AL

The radar

The Northeast Alabama radar (KHTX), 105 km from the middle of the area, began a volume at 00:20 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 00:00Z, 0.3 hours before the alert went out and 168 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, Nashville Metro, TN at 00:00Z on 2021-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 151 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2021-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.1939Sfc1 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
151 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
1019 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

228 
WWUS84 KHUN 190020
SPSHUN

Special Weather Statement
National Weather Service Huntsville AL
720 PM CDT Sun Jul 18 2021
 
ALZ001-004-005-007-190100-
Lawrence AL-Lauderdale AL-Morgan AL-Limestone AL-
720 PM CDT Sun Jul 18 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN LAUDERDALE...
SOUTHWESTERN LIMESTONE...NORTHWESTERN MORGAN AND NORTHEASTERN
LAWRENCE COUNTIES UNTIL 800 PM CDT...

At 719 PM CDT, Doppler radar was tracking a strong thunderstorm 
producing torrential rainfall near Courtland, or 15 miles north of 
Moulton, and moving northeast at 5 mph.

Wind gusts of 30 to 40 mph will be possible with this storm. 
Rainfall rates of 1-2 inches per hour are also occurring and will 
lead to rapid ponding of water on roads and minor flooding in areas 
with poor drainiage.

Locations impacted include...
Decatur, Courtland, North Courtland, Hillsboro, Coxey, Wheeler and
Ripley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Very heavy rainfall is occurring with this storm, and may lead to 
localized flooding. Do not drive your vehicle through flooded 
roadways.

&&

LAT...LON 3459 8726 3475 8736 3488 8711 3468 8698
TIME...MOT...LOC 0019Z 245DEG 6KT 3471 8724 

$$

70/DD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 7:09 PM CDTSpecial Weather StatementHUNMadison36 min
Jul 18, 7:16 PM CDTSpecial Weather StatementHUNCullman44 min
Jul 18, 7:44 PM CDTSpecial Weather StatementHUNFranklin46 min
Jul 18, 9:07 PM CDTFlash Flood WarningHUNLawrence, Limestone, Madison, Morgan3 hr
Jul 19, 9:19 AM CDTFlash Flood WatchHUNColbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more34 hr

Nearby

Special Weather Statements in Alabama, 2021Every special weather statement 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.