Mesoscale Discussion 584

Issued

May 10, 2021, 5:22 PM CDT (22:22 UTC)

Expired

May 10, 2021, 7:45 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

40%

Counties Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Tensas Parish, LA, Winn Parish, LA, Adams County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Jefferson County, MS, Lawrence County, MS, Lincoln County, MS

The Ft Polk radar (KPOE), 137 km from the middle of the area, began a volume at 22:21 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.

045 
ACUS11 KWNS 102223
SWOMCD
SPC MCD 102222 
MSZ000-LAZ000-110045-

Mesoscale Discussion 0584
NWS Storm Prediction Center Norman OK
0522 PM CDT Mon May 10 2021

Areas affected...Northeast Louisiana...Southwest Mississippi

Concerning...Severe potential...Watch possible 

Valid 102222Z - 110045Z

Probability of Watch Issuance...40 percent

SUMMARY...A large hail threat and isolated wind-damage threat will
likely continue for a few more hours across northeast Louisiana. The
wind-damage threat could increase, which would necessitate weather
watch issuance, possibly as far east as southwest Mississippi.

DISCUSSION...The latest radar imagery out of Shreveport shows a
bowing line segment about 40 statute miles southeast of Shreveport.
The line is elevated, and located to the north of a front that is
oriented east-to-west from northeast Texas into southwest
Mississippi. The RAP is estimating MUCAPE in the 1000 to 2000 J/km
range along this corridor. This storm is likely being supported by a
subtle shortwave trough. 500 mb winds associated with the trough are
westerly in the 40 to 50 kt range, which is resulting in sufficient
effective shear for a severe threat. Large hail will continue to be
the main threat over the next hours.

However, further to the east, surface-based instability is greater
with an axis of instability located near the front across southwest
Mississippi. As this storm moves eastward toward this axis of
instability, the storm could become more closely surface-based,
resulting in an increased wind-damage threat. If this happens, then
weather watch issuance could be needed across parts of far northeast
Louisiana and southwest Mississippi.

..Broyles/Hart.. 05/10/2021

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

ATTN...WFO...JAN...LIX...LCH...SHV...

LAT...LON   31458994 31259069 31439221 31489263 31609302 31859306
            32109298 32319284 32449255 32379214 32309128 32058995
            31458994

Mesoscale Discussions in Louisiana, 2021Mesoscale Discussions in Mississippi, 2021Every mesoscale discussion in 2021

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.