Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 360

March 28, 201715 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2017, 7:45 PM CDT for 15 counties in Texas. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Mar 28, 2017, 7:45 PM CDT (00:45 UTC)
Expired: Mar 28, 2017, 8:45 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

Counties Armstrong County, TX, Briscoe County, TX, Carson County, TX, Castro County, TX, Crosby County, TX, Deaf Smith County, TX, Donley County, TX, Floyd County, TX, Gray County, TX, Hale County, TX, Lamb County, TX, Lubbock County, TX, Potter County, TX, Randall County, TX, Swisher County, TX

The radar

The Lubbock radar (KLBB), 91 km from the middle of the area, began a volume at 00:49 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, 0.8 hours before the alert went out and 98 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 36 J/kg
Mixed-layer CIN: -184 J/kg
Mixed-layer LCL: 841 m above ground
0-6 km bulk shear: 68 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

156 
ACUS11 KWNS 290045
SWOMCD
SPC MCD 290045 
TXZ000-290145-

Mesoscale Discussion 0360
NWS Storm Prediction Center Norman OK
0745 PM CDT Tue Mar 28 2017

Areas affected...Portions of the TX Panhandle/South Plains

Concerning...Severe Thunderstorm Watch 93...

Valid 290045Z - 290145Z

The severe weather threat for Severe Thunderstorm Watch 93
continues.

SUMMARY...While an isolated marginal severe risk continues across
remaining-valid portions of Watch 93, additional Watch issuance is
unlikely.

DISCUSSION...Convection has intensified along an eastward-advancing
Pacific cold front; which has merged with a southwestward-moving,
convectively reinforced boundary -- across southwestern parts of the
TX Panhandle and the western TX South Plains. Steep midlevel lapse
rates sampled by NM/west TX 00Z soundings suggest that a few robust
convective cores will be possible during the next few hours.
However, inflow for this activity will remain rooted above the
stable surface layer, while elevated CAPE layers erode owing to the
influx of cooler low-level air from the north/northeast. As a
result, convection may weaken as it advances farther east,
particularly while exhibiting a cluster-type mode (as opposed to
discrete supercells). While a few instances of small to marginally
severe hail may occur -- aided by 45-60 kt of effective shear --
additional Watch issuance is unlikely.

..Cohen.. 03/29/2017

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

ATTN...WFO...LUB...AMA...

LAT...LON   33140176 34200249 35260273 35500206 35460046 35160021
            34880036 34760106 34350123 33570120 33190124 33140176

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 28, 9:07 PM CDT	Mesoscale Discussion	SPC	Bandera, Bexar, Blanco, Brown, Burnet, Callahan and 37 more	23 min
Mar 28, 9:28 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bell, Bexar, Blanco, Bosque and 78 more	8 hr
Mar 28, 10:21 PM CDT	Severe Thunderstorm Watch	SPC	Archer, Baylor, Clay, Wichita, Wilbarger	7 hr
Mar 28, 10:25 PM CDT	Mesoscale Discussion	SPC	Archer, Clay, Cooke, Montague, Wichita	65 min
Mar 28, 11:58 PM CDT	Mesoscale Discussion	SPC	Anderson, Bastrop, Bell, Bexar, Blanco, Bosque and 29 more	92 min
Mar 29, 2:54 AM CDT	Mesoscale Discussion	SPC	Collin, Delta, Fannin, Franklin, Grayson, Hopkins and 7 more	96 min
Mar 29, 8:23 AM CDT	Mesoscale Discussion	SPC	Brazoria, Calhoun, Chambers, Fort Bend, Galveston, Hardin and 12 more	67 min
Mar 29, 1:31 PM CDT	Mesoscale Discussion	SPC	Brazoria, Chambers, Galveston, Hardin, Harris, Jasper and 7 more	2 hr
Mar 29, 2:11 PM CDT	Tornado Watch	SPC	Angelina, Chambers, Galveston, Hardin, Jasper, Jefferson and 6 more	7 hr
Mar 29, 4:17 PM CDT	Tornado Watch	SPC	Bowie, Cass, Morris	8 hr
Mar 29, 5:50 PM CDT	Mesoscale Discussion	SPC	Jasper, Newton, Orange	115 min

Nearby

Mesoscale Discussions in Texas, 2017 Every 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.