Alert archive / Arkansas / Mesoscale Discussions in 2021

Mesoscale Discussion 519

May 4, 202122 counties in Arkansas; Butler County, Carter County, Ripley County, Missouri

The Storm Prediction Center issued this mesoscale discussion at May 4, 2021, 2:02 AM CDT for 22 counties in Arkansas; Butler County, Carter County, Ripley County, Missouri. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
May 4, 2021, 2:02 AM CDT (07:02 UTC)
Expired
May 4, 2021, 3:30 AM CDT
In force
88 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 137
All 25 counties

Clay County, AR, Conway County, AR, Craighead County, AR, Cross County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Greene County, AR, Hot Spring County, AR, Jackson County, AR, Jefferson County, AR, Lawrence County, AR, Lonoke County, AR, Monroe County, AR, Perry County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, White County, AR, Woodruff County, AR, Butler County, MO, Carter County, MO, Ripley County, MO

The radar

The Little Rock radar (KLZK), 95 km from the middle of the area, began a volume at 07:04 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, 7.0 hours before the alert went out and 184 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 2021-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3608 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 2021-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 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
3608 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
1081 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
199 m²/s²
Significant tornado parameter
2.3
Supercell composite
15.3

Open this sounding in Storm Lab

The text

As transmitted.

487 
ACUS11 KWNS 040702
SWOMCD
SPC MCD 040702 
MOZ000-ARZ000-040830-

Mesoscale Discussion 0519
NWS Storm Prediction Center Norman OK
0202 AM CDT Tue May 04 2021

Areas affected...central and northeastern Arkansas and into
southeastern Missouri

Concerning...Severe Thunderstorm Watch 137...

Valid 040702Z - 040830Z

The severe weather threat for Severe Thunderstorm Watch 137
continues.

SUMMARY...Strong/locally severe storms continue to advance across
northeastern and central Arkansas, where damaging winds continue to
pose severe risk.

DISCUSSION...Latest radar loop continues to show a fairly
well-organized bowing cluster of storms moving across northeastern
Arkansas and adjacent southeastern Missouri, with vigorous storms
developing eastward toward the Mississippi Valley just ahead of the
bow in a wing of warm advection.

Meanwhile, a second/organized cluster of storms is ongoing just to
the southwest, which will move northeastward across central Arkansas
at around 45 kt over the next 1 to 2 hours.  These storms are most
intense in the vicinity of a west-to-east outflow boundary laid out
by the bowing cluster to the north, that has sagged southward into
the Little Rock area.  A 62 kt gust has recently been reported near
Hot Springs with this cluster, and expect strong/possibly damaging
winds will affect the Little Rock metro area beginning within the
next half hour or so.

..Goss.. 05/04/2021

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

ATTN...WFO...PAH...MEG...LZK...SGF...

LAT...LON   37079136 35899136 35449173 35189318 34069319 34109245
            34579099 36859018 37079136

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 8:38 PM CDTMesoscale DiscussionSPCArkansas, Baxter, Boone, Calhoun, Carroll, Clark and 60 more2 hr
May 3, 9:10 PM CDTSevere Thunderstorm WatchSPCBaxter, Benton, Boone, Calhoun, Carroll, Clark and 50 more7 hr
May 3, 10:22 PM CDTMesoscale DiscussionSPCBoone, Crawford, Franklin, Johnson, Madison, Marion and 2 more83 min
May 3, 11:34 PM CDTMesoscale DiscussionSPCBaxter, Boone, Carroll, Clark, Cleburne, Conway and 27 more86 min
May 4, 1:06 AM CDTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Greene, Jackson and 5 more114 min
May 4, 1:41 AM CDTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Mississippi and 2 more6 hr
May 4, 4:17 AM CDTMesoscale DiscussionSPCCrittenden88 min
May 4, 6:44 AM CDTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 8 more2 hr
May 4, 10:52 AM CDTTornado WatchSPCAshley, Bradley, Calhoun, Chicot, Columbia, Desha and 2 more7 hr
May 4, 11:58 AM CDTMesoscale DiscussionSPCCrittenden, Lee, Phillips2 hr
May 4, 12:18 PM CDTSevere Thunderstorm WatchSPCPhillips5 hr
May 4, 1:59 PM CDTMesoscale DiscussionSPCCleburne, Conway, Craighead, Cross, Faulkner, Greene and 17 more2 hr

Nearby

Mesoscale Discussions in Arkansas, 2021Mesoscale Discussions in Missouri, 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.