Alert archive / Alabama / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 166, NWS Birmingham, AL

April 24, 1999St. Clair County, Alabama

NWS Birmingham, AL issued this severe thunderstorm warning at Apr 24, 1999, 4:39 PM CDT for St. Clair County, Alabama. It was in force for 36 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
Apr 24, 1999, 4:39 PM CDT (21:39 UTC)
Expired
Apr 24, 1999, 5:15 PM CDT
In force
36 min
Issued by
NWS Birmingham, AL
Area
Whole counties

County St. Clair County, AL

The radar

The Birmingham radar (KBMX), 74 km from the middle of the area, began a volume at 21:39 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 12:00Z, 9.7 hours before the alert went out and 74 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, Birmingham, AL at 12:00Z on 1999-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2163 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, Birmingham, AL at 12:00Z on 1999-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 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
2163 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
634 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
74 m²/s²
Significant tornado parameter
0.5
Supercell composite
2.9

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 24, 2:04 PM CDTSevere Thunderstorm WarningBMXPickens51 min
Apr 24, 2:31 PM CDTSevere Thunderstorm WarningBMXCalhoun49 min
Apr 24, 2:51 PM CDTSevere Thunderstorm WarningBMXPickens49 min
Apr 24, 3:12 PM CDTSevere Thunderstorm WarningBMXCleburne48 min
Apr 24, 3:19 PM CDTSevere Thunderstorm WarningBMXCalhoun36 min
Apr 24, 4:26 PM CDTSevere Thunderstorm WarningBMXMarengo49 min
Apr 24, 4:57 PM CDTSevere Thunderstorm WarningBMXCalhoun48 min
Apr 24, 5:15 PM CDTSevere Thunderstorm WarningBMXMarengo35 min
Apr 24, 5:55 PM CDTFlash Flood WarningBMXCalhoun2 hr

Nearby

Severe Thunderstorm Warnings in Alabama, 1999Every severe thunderstorm warning in 1999

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.