Alert archive / Mississippi / Mesoscale Discussions in 2021

Mesoscale Discussion 143

February 28, 2021Colbert County, Lauderdale County, Alabama; 6 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2021, 8:49 PM CST for Colbert County, Lauderdale County, Alabama; 6 counties in Mississippi. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Feb 28, 2021, 8:49 PM CST (02:49 UTC)
Expired
Feb 28, 2021, 9:45 PM CST
In force
56 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Colbert County, AL, Lauderdale County, AL, Alcorn County, MS, Benton County, MS, Prentiss County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS

The radar

The Columbus AFB radar (KGWX), 96 km from the middle of the area, began a volume at 02:48 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

Little Rock, AR (KLZK), launched 00:00Z, 2.8 hours before the alert went out and 152 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, Little Rock, AR at 00:00Z on 2021-03-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 229 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, Little Rock, AR at 00:00Z on 2021-03-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -399 square meters per square second.1939587897Sfc1 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
229 J/kg
Mixed-layer CIN
-269 J/kg
Mixed-layer LCL
782 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
-399 m²/s²
0-3 km storm-relative helicity
-284 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.4

Open this sounding in Storm Lab

The text

As transmitted.

466 
ACUS11 KWNS 010249
SWOMCD
SPC MCD 010249 
ALZ000-TNZ000-MSZ000-010345-

Mesoscale Discussion 0143
NWS Storm Prediction Center Norman OK
0849 PM CST Sun Feb 28 2021

Areas affected...Northeast Mississippi...far northwest Alabama...and
far southern Tennessee

Concerning...Severe potential...Watch unlikely 

Valid 010249Z - 010345Z

Probability of Watch Issuance...20 percent

SUMMARY...A well developed storm in northern Mississippi may pose a
severe threat for the next 30 to 45 minutes before weakening.

DISCUSSION...A well developed supercell in northern Mississippi will
continue northeastward over the next hour. However, the airmass
downstream of this storm is characterized by increasing inhibition
and limited instability with dewpoints near 60 degrees. This storm
will be capable of some damaging winds for the next 30 to 45 minutes
but should weaken beyond that time. Therefore, no downstream watch
is anticipated.

..Bentley/Goss.. 03/01/2021

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

ATTN...WFO...OHX...HUN...MEG...

LAT...LON   34908919 35248778 35118712 34958719 34858729 34688767
            34448828 34398880 34408914 34518957 34908919

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 28, 6:27 PM CSTMesoscale DiscussionSPCAlcorn, Benton, Bolivar, Coahoma, DeSoto, Lafayette and 7 more93 min

Nearby

Mesoscale Discussions in Mississippi, 2021Mesoscale 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.