Alert archive / Alabama / Mesoscale Discussions in 2021

Mesoscale Discussion 889

June 8, 202110 counties in Alabama

The Storm Prediction Center issued this mesoscale discussion at Jun 8, 2021, 6:06 PM CDT for 10 counties in Alabama. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Jun 8, 2021, 6:06 PM CDT (23:06 UTC)
Expired
Jun 8, 2021, 7:00 PM CDT
In force
54 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
5%

Counties Blount County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Lawrence County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Walker County, AL, Winston County, AL

The radar

The Northeast Alabama radar (KHTX), 104 km from the middle of the area, began a volume at 23:07 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, 11.1 hours before the alert went out and 116 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 2021-06-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 422 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 2021-06-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 66 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
422 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
555 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
122 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

598 
ACUS11 KWNS 082306
SWOMCD
SPC MCD 082306 
ALZ000-090000-

Mesoscale Discussion 0889
NWS Storm Prediction Center Norman OK
0606 PM CDT Tue Jun 08 2021

Areas affected...portions of northern Alabama

Concerning...Severe potential...Watch unlikely 

Valid 082306Z - 090000Z

Probability of Watch Issuance...5 percent

SUMMARY...An isolated damaging wind threat will persist across
northern Alabama for the next 2 hours.

DISCUSSION...A broken line of storms is currently moving across
northern Alabama while another broken line of storms is lifting
northward across the state. The airmass downstream of both these
lines is moist/unstable and occasional stronger storms are possible.
However, the KBMX VWP shows less than 25 kts of unidirectional flow
and thus shear is weak. The portion of the line in Winston county at
23Z has recently surged with a slightly stronger wind signature from
the KGWX WSR-88D. While most winds are expected to remain below
severe limits, isolated damage may occur from 40 to 50 mph winds
with this activity.

..Bentley/Thompson.. 06/08/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BMX...HUN...

LAT...LON   34338754 34728712 34878637 34768603 34488572 34178575
            33868615 33788681 33688738 33658770 33998780 34338754

Nearby

Mesoscale Discussions in Alabama, 2021Every mesoscale discussion 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.