Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 239

March 18, 201629 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2016, 6:05 PM CDT for 29 counties in Texas. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Mar 18, 2016, 6:05 PM CDT (23:05 UTC)
Expired
Mar 18, 2016, 7:00 PM CDT
In force
55 min
Issued by
the Storm Prediction Center
All 29 counties

Atascosa County, TX, Bandera County, TX, Bastrop County, TX, Bell County, TX, Bexar County, TX, Blanco County, TX, Burnet County, TX, Caldwell County, TX, Comal County, TX, Dimmit County, TX, Edwards County, TX, Fayette County, TX, Frio County, TX, Gillespie County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Kerr County, TX, Kinney County, TX, Llano County, TX, Maverick County, TX, Medina County, TX, Real County, TX, Travis County, TX, Uvalde County, TX, Williamson County, TX, Wilson County, TX, Zavala County, TX

The radar

The Austin/San Antonio radar (KEWX), 110 km from the middle of the area, began a volume at 23:06 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

Del Rio, TX (KDLF), launched 12:00Z, 11.1 hours before the alert went out and 171 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, Del Rio, TX at 12:00Z on 2016-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2117 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, Del Rio, TX at 12:00Z on 2016-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 89 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
2117 J/kg
Mixed-layer CIN
-117 J/kg
Mixed-layer LCL
542 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
89 m²/s²
0-3 km storm-relative helicity
117 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

As transmitted.

863 
ACUS11 KWNS 182305
SWOMCD
SPC MCD 182305 
TXZ000-190000-

MESOSCALE DISCUSSION 0239
NWS STORM PREDICTION CENTER NORMAN OK
0605 PM CDT FRI MAR 18 2016

AREAS AFFECTED...SOUTH CENTRAL TEXAS

CONCERNING...SEVERE THUNDERSTORM WATCH 48...

VALID 182305Z - 190000Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 48
CONTINUES.

SUMMARY...TSTMS ARE EXPECTED TO EXPAND IN AREAL COVERAGE AS THEY
PROPAGATE SOUTH ACROSS WW48.  HAIL REMAINS THE GREATEST RISK.

DISCUSSION...CONVECTION CONTINUES TO EXPAND IN AREAL COVERAGE ALONG
SURGING COLD FRONT THAT HAS PROGRESSED TO THE BALCONES ESCARPMENT. 
DEEP-LAYER SHEAR IS ADEQUATE FOR MAINTENANCE OF SEVERE MULTI-CELL
UPDRAFTS AND PERHAPS AN ISOLATED SUPERCELL.  THIS ACTIVITY IS
EXPECTED TO PROPAGATE SWD ACROSS THE REMAINDER OF WW48 OVER THE NEXT
SEVERAL HOURS WHERE LAPSE RATES/INSTABILITY REMAIN FAVORABLE FOR
STRONG UPDRAFTS.

FARTHER WEST...CONSIDERABLE AMOUNT OF CONVECTION HAS EVOLVED OFF THE
HIGHER TERRAIN OF NRN MEXICO...WEST OF THE RIO GRANDE RIVER.  RADAR
DATA SUGGESTS A WELL-DEFINED BOW-TYPE STRUCTURE HAS EVOLVED FROM
THIS LARGER COMPLEX OF STORMS ROUGHLY 75MI SSW OF DRT.  THIS
ACTIVITY IS EXPECTED TO DRIVE SEWD TOWARD THE MIDDLE RIO GRANDE
RIVER VALLEY LATER THIS EVENING ALONG A STRONG INSTABILITY AXIS WITH
MUCAPE ON THE ORDER OF 4000 J/KG.  THIS ACTIVITY WILL BE MONITORED
CLOSELY.

..DARROW.. 03/18/2016

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

ATTN...WFO...HGX...FWD...CRP...EWX...SJT...

LAT...LON   27960014 29700096 31409748 29649667 27960014

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 6:04 AM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Collin, Cooke, Cottle and 10 more2 hr
Mar 18, 9:51 AM CDTMesoscale DiscussionSPCBowie, Cass, Delta, Fannin, Franklin, Grayson and 4 more84 min
Mar 18, 1:16 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Gregg, Harrison, Marion and 4 more59 min
Mar 18, 1:35 PM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Cherokee, Franklin, Gregg and 10 more6 hr
Mar 18, 1:57 PM CDTMesoscale DiscussionSPCBandera, Crockett, Edwards, Gillespie, Kendall, Kerr and 8 more2 hr
Mar 18, 3:47 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Cherokee, Franklin, Gregg and 13 more118 min
Mar 18, 4:09 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bastrop, Bell, Bexar, Blanco and 31 more7 hr

Nearby

Mesoscale Discussions in Texas, 2016Every mesoscale discussion in 2016

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.