Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 646

May 16, 20219 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 16, 2021, 10:46 PM CDT for 9 counties in Texas. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
May 16, 2021, 10:46 PM CDT (03:46 UTC)
Expired
May 16, 2021, 11:45 PM CDT
In force
59 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 179...180

Counties Baylor County, TX, Cottle County, TX, Dickens County, TX, Foard County, TX, Haskell County, TX, King County, TX, Knox County, TX, Stonewall County, TX, Throckmorton County, TX

The radar

The Altus AFB radar (KFDR), 121 km from the middle of the area, began a volume at 03:49 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

Amarillo Airport, TX (KAMA), launched 00:00Z, 3.8 hours before the alert went out and 225 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, Amarillo Airport, TX at 00:00Z on 2021-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 449 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, Amarillo Airport, TX at 00:00Z on 2021-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 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
449 J/kg
Mixed-layer CIN
-105 J/kg
Mixed-layer LCL
2191 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
250 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.5

Open this sounding in Storm Lab

The text

As transmitted.

394 
ACUS11 KWNS 170347
SWOMCD
SPC MCD 170346 
TXZ000-170445-

Mesoscale Discussion 0646
NWS Storm Prediction Center Norman OK
1046 PM CDT Sun May 16 2021

Areas affected...northwest Texas

Concerning...Severe Thunderstorm Watch 179...180...

Valid 170346Z - 170445Z

The severe weather threat for Severe Thunderstorm Watch 179, 180
continues.

SUMMARY...Storms developing through northwest Texas will continue to
pose a threat for damaging wind and large hail through 05Z.

DISCUSSION...Overall trend has been for storms moving southeast and
entering northwest TX to weaken. Another cluster of more discrete
cells is moving northward, and the outflow from these two clusters
should merge by 0430Z. Some intensification may occur, at least
temporarily, during the merger with damaging wind and large hail
remaining the primary threats. After the merger, storms might
reorganize and continue developing southeast along a consolidated
outflow boundary. However, uncertainty exists regarding how severe
storms will be, especially given weak forcing aloft and increasing
convective inhibition with respect to near surface-based parcels.

..Dial.. 05/17/2021

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

ATTN...WFO...FWD...OUN...SJT...LUB...

LAT...LON   34440027 33569872 32949937 33150062 33880103 34440027

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 16, 7:08 PM CDTSevere Thunderstorm WatchSPCCottle, Crosby, Dickens, Floyd, Garza, Hale and 8 more6 hr
May 16, 8:54 PM CDTMesoscale DiscussionSPCBriscoe, Cottle, Foard, Hall, King, Knox and 1 more96 min
May 16, 9:38 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Clay, Foard, Hardeman, Haskell and 10 more4 hr
May 17, 1:09 AM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Crosby, Dickens, Fisher and 17 more96 min
May 17, 9:18 AM CDTMesoscale DiscussionSPCJasper, Jefferson, Newton, Orange117 min
May 17, 12:47 PM CDTMesoscale DiscussionSPCAustin, Bastrop, Bell, Blanco, Brazoria, Brazos and 29 more88 min
May 17, 1:39 PM CDTMesoscale DiscussionSPCDallam, Hartley, Oldham2 hr
May 17, 2:11 PM CDTMesoscale DiscussionSPCAndrews, Bailey, Borden, Castro, Cochran, Crane and 20 more2 hr
May 17, 2:39 PM CDTSevere Thunderstorm WatchSPCArmstrong, Carson, Collingsworth, Dallam, Donley, Gray and 10 more8 hr
May 17, 3:04 PM CDTTornado WatchSPCAndrews, Bailey, Borden, Briscoe, Castro, Cochran and 39 more8 hr
May 17, 4:44 PM CDTTornado WatchSPCBaylor, Childress, Cottle, Fisher, Foard, Hardeman and 10 more6 hr
May 17, 4:53 PM CDTMesoscale DiscussionSPCBaylor, Callahan, Childress, Cottle, Fisher, Foard and 11 more97 min
May 17, 5:10 PM CDTMesoscale DiscussionSPCDallam, Hansford, Hartley, Hutchinson, Moore, Ochiltree and 3 more2 hr
May 17, 5:36 PM CDTMesoscale DiscussionSPCAndrews, Armstrong, Bailey, Borden, Briscoe, Castro and 38 more84 min
May 17, 6:13 PM CDTMesoscale DiscussionSPCDimmit, La Salle, Webb92 min
May 17, 6:40 PM CDTSevere Thunderstorm WatchSPCDimmit, Frio, La Salle, Maverick, Webb, Zavala4 hr

Nearby

Mesoscale Discussions in Texas, 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.