Alert archive / Texas / Mesoscale Discussions in 2018

Mesoscale Discussion 404

May 13, 201813 counties in Kansas; 12 counties in Oklahoma; 20 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 13, 2018, 7:14 PM CDT for 13 counties in Kansas; 12 counties in Oklahoma; 20 counties in Texas. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
May 13, 2018, 7:14 PM CDT (00:14 UTC)
Expired
May 13, 2018, 8:45 PM CDT
In force
91 min
Issued by
the Storm Prediction Center
All 45 counties

Barber County, KS, Barton County, KS, Clark County, KS, Comanche County, KS, Edwards County, KS, Ford County, KS, Hodgeman County, KS, Kiowa County, KS, Meade County, KS, Pawnee County, KS, Pratt County, KS, Rush County, KS, Stafford County, KS, Beaver County, OK, Beckham County, OK, Custer County, OK, Dewey County, OK, Ellis County, OK, Greer County, OK, Harmon County, OK, Harper County, OK, Jackson County, OK, Roger Mills County, OK, Woods County, OK, Woodward County, OK, Briscoe County, TX, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Crosby County, TX, Dickens County, TX, Donley County, TX, Floyd County, TX, Foard County, TX, Gray County, TX, Hall County, TX, Hardeman County, TX, Hemphill County, TX, King County, TX, Knox County, TX, Lipscomb County, TX, Motley County, TX, Ochiltree County, TX, Roberts County, TX, Wheeler County, TX

The radar

The Altus AFB radar (KFDR), 160 km from the middle of the area, began a volume at 00:15 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, 0.2 hours before the alert went out and 169 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 2018-05-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 2018-05-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3885 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

606 
ACUS11 KWNS 140014
SWOMCD
SPC MCD 140014 
OKZ000-KSZ000-TXZ000-140145-

Mesoscale Discussion 0404
NWS Storm Prediction Center Norman OK
0714 PM CDT Sun May 13 2018

Areas affected...Southwest KS...Western OK...Northwest TX...Eastern
TX/OK Panhandles

Concerning...Severe Thunderstorm Watch 87...

Valid 140014Z - 140145Z

The severe weather threat for Severe Thunderstorm Watch 87
continues.

SUMMARY...A gradual weakening trend is expected with ongoing storms
this evening, though some hail/wind risk will continue in the short
term.

DISCUSSION...At 00Z, intense thunderstorms are ongoing from
southwest KS into the TX Panhandle, generally along and east of a
northwestward-retreating surface boundary. A gradual decreasing
trend has been noted with many of cells over the past hour, and a
general decreasing trend is expected to continue into the evening as
surface-based CINH increases. However, strong instability and
sufficient effective shear will continue to support a hail/wind
threat for at least the next 1-2 hours, especially across the
eastern TX Panhandle where several cell mergers are ongoing, and
also across southwest KS in the vicinity of the surface boundary.
Isolated instances of very large hail remain possible in the short
term given the magnitude of instability. 

Later tonight, an increasing low-level jet will support development
of elevated convection to the north of the surface boundary. Some
hail risk may accompany this activity, though any such risk would
likely remain north of areas currently in WW 87.

..Dean.. 05/14/2018

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

ATTN...WFO...ICT...OUN...DDC...LUB...AMA...

LAT...LON   33450151 35910113 38090012 38529960 38589859 37409857
            35889882 34599937 34149961 33589965 33450023 33450151

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 13, 8:00 PM CDTMesoscale DiscussionSPCAtchison, Brown, Clay, Cloud, Dickinson, Doniphan and 22 more3 hr
May 14, 12:54 PM CDTMesoscale DiscussionSPCAllen, Anderson, Bourbon, Butler, Chase, Coffey and 13 more96 min
May 14, 1:20 PM CDTSevere Thunderstorm WatchSPCAllen, Anderson, Bourbon, Butler, Chase, Chautauqua and 28 more11 hr
May 14, 5:04 PM CDTMesoscale DiscussionSPCLogan, Sherman, Wallace116 min
May 14, 3:10 PM CDTMesoscale DiscussionSPCAlfalfa, Beckham, Blaine, Custer, Dewey, Garfield and 10 more2 hr
May 14, 4:39 PM CDTSevere Thunderstorm WatchSPCAlfalfa, Beckham, Blaine, Caddo, Custer, Dewey and 16 more6 hr
May 14, 2:32 PM CDTMesoscale DiscussionSPCBaylor, Coke, Cottle, Crockett, Dickens, Fisher and 21 more88 min

Nearby

Mesoscale Discussions in Texas, 2018Mesoscale Discussions in Kansas, 2018Mesoscale Discussions in Oklahoma, 2018Every mesoscale discussion in 2018

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.