Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 730

May 16, 20178 counties in Oklahoma; 13 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 16, 2017, 1:19 PM CDT for 8 counties in Oklahoma; 13 counties in Texas. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
May 16, 2017, 1:19 PM CDT (18:19 UTC)
Expired
May 16, 2017, 2:15 PM CDT
In force
56 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 21 counties

Beaver County, OK, Beckham County, OK, Ellis County, OK, Greer County, OK, Harmon County, OK, Harper County, OK, Roger Mills County, OK, Woodward County, OK, Briscoe County, TX, Carson County, TX, Childress County, TX, Collingsworth County, TX, Donley County, TX, Gray County, TX, Hall County, TX, Hardeman County, TX, Hemphill County, TX, Lipscomb County, TX, Ochiltree County, TX, Roberts County, TX, Wheeler County, TX

The radar

The Amarillo radar (KAMA), 132 km from the middle of the area, began a volume at 18:22 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 12:00Z, 6.3 hours before the alert went out and 131 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 12:00Z on 2017-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 837 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 12:00Z on 2017-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 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
837 J/kg
Mixed-layer CIN
-240 J/kg
Mixed-layer LCL
1292 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

647 
ACUS11 KWNS 161819
SWOMCD
SPC MCD 161819 
KSZ000-OKZ000-TXZ000-161915-

Mesoscale Discussion 0730
NWS Storm Prediction Center Norman OK
0119 PM CDT Tue May 16 2017

Areas affected...eastern tx/ok panhandle...western ok

Concerning...Severe potential...Tornado Watch likely 

Valid 161819Z - 161915Z

Probability of Watch Issuance...95 percent

SUMMARY...Severe thunderstorms will develop across the eastern TX/OK
Panhandles over the next few hours.  Tornadoes are expected with
this activity, along with very large hail and severe wind gusts. 
Tornado watch will be issued by mid afternoon.

DISCUSSION...Latest visible satellite imagery suggests large-scale
forcing for ascent is spreading across the southern Rockies, per
marked increase in showers and thunderstorms over western/central
NM.  Downstream, dry line has mixed east and is becoming well
defined over the TX Panhandle/South Plains region with substantial
boundary-layer cu immediately east of the dry line.  Towering cu,
and a few attempts at glaciation, are noted over
Hutchinson/Hansford/Ochiltree Counties.  There is increasing
confidence supercells will develop across the eastern TX/OK
Panhandles by mid afternoon with subsequent movement expected into
western portions of OK/southwest KS into the evening. Environmental
conditions appear favorable for tornadoes and very large hail as
steep lapse rates are evident on 12z soundings and surface dew
points have now risen into the mid 60s.  Environmental conditions
appear favorable for a few strong tornadoes.

..Darrow/Hart.. 05/16/2017

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

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

LAT...LON   34400122 35680143 37270015 37069899 35189945 34189949
            34400122

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 16, 1:54 PM CDTTornado Watch PDSSPCBeaver, Beckham, Blaine, Caddo, Custer, Dewey and 12 more8 hr
May 16, 3:36 PM CDTMesoscale DiscussionSPCBeaver, Beckham, Ellis, Greer, Harmon, Harper and 2 more54 min
May 16, 4:56 PM CDTMesoscale DiscussionSPCCollingsworth, Wheeler64 min
May 16, 5:29 PM CDTMesoscale DiscussionSPCBorden, Coke, Crockett, Fisher, Garza, Glasscock and 14 more2 hr

Nearby

Mesoscale Discussions in Texas, 2017Mesoscale Discussions in Oklahoma, 2017Every mesoscale discussion in 2017

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.