Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 310

April 16, 201521 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 16, 2015, 12:49 PM CDT for 21 counties in Texas. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued
Apr 16, 2015, 12:49 PM CDT (17:49 UTC)
Expired
Apr 16, 2015, 2:45 PM CDT
In force
116 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 21 counties

Armstrong County, TX, Briscoe County, TX, Carson County, TX, Castro County, TX, Crosby County, TX, Donley County, TX, Floyd County, TX, Garza County, TX, Gray County, TX, Hale County, TX, Hall County, TX, Hutchinson County, TX, Lubbock County, TX, Lynn County, TX, Moore County, TX, Motley County, TX, Ochiltree County, TX, Potter County, TX, Randall County, TX, Roberts County, TX, Swisher County, TX

The radar

The Amarillo radar (KAMA), 45 km from the middle of the area, began a volume at 17:52 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, 5.8 hours before the alert went out and 44 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 2015-04-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 246 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Amarillo Airport, TX at 12:00Z on 2015-04-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 160 square meters per square second.19395878Sfc1 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
246 J/kg
Mixed-layer CIN
-181 J/kg
Mixed-layer LCL
2122 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

307 
ACUS11 KWNS 161750
SWOMCD
SPC MCD 161749 
TXZ000-161945-

MESOSCALE DISCUSSION 0310
NWS STORM PREDICTION CENTER NORMAN OK
1249 PM CDT THU APR 16 2015

AREAS AFFECTED...TEXAS PANHANDLE...SOUTH PLAINS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 161749Z - 161945Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SEVERE STORM DEVELOPMENT APPEARS INCREASINGLY POSSIBLE
THROUGH THE 19-21Z TIME FRAME.  THIS SHOULD INCLUDE ISOLATED
SUPERCELLS.

DISCUSSION...CONVECTION ALLOWING MODELS...INCLUDING THE HIGH
RESOLUTION RAPID REFRESH...HAVE BEEN SUGGESTIVE THAT STORM
INITIATION MAY OCCUR ALONG THE DRYLINE AS EARLY AS THE 19-21Z.  THIS
APPEARS REASONABLE GIVEN GRADUAL MID-LEVEL COOLING...FROM WEST TO
EAST ACROSS THE TEXAS PANHANDLE AND PORTIONS OF THE SOUTH
PLAINS...ANTICIPATED DURING THE NEXT FEW HOURS IN THE WAKE OF AN
INITIAL MID-LEVEL IMPULSE PIVOTING AROUND THE FOUR CORNERS LOW.

COINCIDING WITH WITH GRADUAL NORTHWARD/NORTHWESTWARD RETURN OF
LOW-LEVEL MOISTURE TOWARD THE SOUTHERN HIGH PLAINS...SUPPORTING
MIXED LAYER CAPE ON THE ORDER OF 1000-2000 J/KG...THE ENVIRONMENT
APPEARS TO BE IN THE PROCESS OF BECOMING INCREASINGLY CONDUCIVE TO
SUPERCELLS.  DEEP LAYER SHEAR IS ALREADY SUFFICIENT...BENEATH THE
EASTERN PERIPHERY OF 40-50 KT SOUTH SOUTHWESTERLY 500 MB FLOW.

LOW-LEVEL FLOW FIELDS ARE EXPECTED TO REMAIN FAIRLY WEAK INTO EARLY
EVENING.  HOWEVER...IT IS POSSIBLE THAT AN INCREASINGLY BETTER
DEFINED BAROCLINIC ZONE ON THE LEADING EDGE OF A SHALLOW
STALLING/MODIFYING COLD FRONT /WHICH HAS SURGED THROUGH THE CENTRAL
HIGH PLAINS/ COULD PROVIDE THE FOCUS FOR SOMEWHAT ENHANCED TORNADIC
POTENTIAL LATER THIS AFTERNOON.

..KERR/THOMPSON.. 04/16/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON   35210241 35800215 36240142 36300060 35540050 33970043
            33110135 33060218 34040225 35210241

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 16, 1:34 PM CDTMesoscale DiscussionSPCAustin, Bastrop, Bell, Bexar, Blanco, Bosque and 48 more116 min
Apr 16, 1:48 PM CDTTornado WatchSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hansford and 8 more8 hr
Apr 16, 2:22 PM CDTSevere Thunderstorm WatchSPCAnderson, Aransas, Austin, Bastrop, Bee, Bell and 81 more8 hr
Apr 16, 2:42 PM CDTMesoscale DiscussionSPCAnderson, Aransas, Austin, Bastrop, Bee, Bell and 75 more63 min
Apr 16, 4:06 PM CDTMesoscale DiscussionSPCArcher, Baylor, Borden, Brown, Callahan, Childress and 46 more2 hr
Apr 16, 4:40 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Briscoe, Brown, Callahan, Castro and 45 more7 hr
Apr 16, 4:59 PM CDTMesoscale DiscussionSPCAngelina, Cherokee, Gregg, Hardin, Houston, Jasper and 12 more91 min
Apr 16, 5:06 PM CDTMesoscale DiscussionSPCArmstrong, Carson, Collingsworth, Donley, Gray, Hansford and 7 more84 min
Apr 16, 5:29 PM CDTMesoscale DiscussionSPCBailey, Dallam, Deaf Smith, Hartley, Oldham, Parmer91 min
Apr 16, 6:19 PM CDTMesoscale DiscussionSPCAnderson, Aransas, Austin, Bastrop, Bell, Bexar and 84 more86 min

Nearby

Mesoscale Discussions in Texas, 2015Every mesoscale discussion in 2015

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.