Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 372

April 12, 201615 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2016, 3:54 PM CDT for 15 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 12, 2016, 3:54 PM CDT (20:54 UTC)
Expired: Apr 12, 2016, 6:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Bandera County, TX, Edwards County, TX, Gillespie County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Mason County, TX, Maverick County, TX, Menard County, TX, Real County, TX, Schleicher County, TX, Sutton County, TX, Uvalde County, TX, Val Verde County, TX, Zavala County, TX

The radar

The Laughlin AFB radar (KDFX), 72 km from the middle of the area, began a volume at 20:54 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.

Severe Thunderstorm Watch 87Apr 12, 7:45 PM CDT

The nearest sounding before it

Del Rio, TX (KDLF), launched 12:00Z, 8.9 hours before the alert went out and 19 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 948 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 127 m²/s²
0-3 km storm-relative helicity: 236 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.3

Open this sounding in Storm Lab

The text

As transmitted.

802 
ACUS11 KWNS 122055
SWOMCD
SPC MCD 122054 
TXZ000-122300-

MESOSCALE DISCUSSION 0372
NWS STORM PREDICTION CENTER NORMAN OK
0354 PM CDT TUE APR 12 2016

AREAS AFFECTED...PARTS OF THE TEXAS HILL COUNTRY AND ADJACENT RIO
GRANDE VALLEY AREA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 122054Z - 122300Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...A MORE SUBSTANTIVE INCREASE IN SEVERE WEATHER POTENTIAL
MAY NOT OCCUR UNTIL AFTER 00Z...BUT AN ISOLATED STORM MAY APPROACH
VAL VERDE COUNTY WITH SOME RISK FOR SEVERE HAIL/WIND GUSTS WITHIN
THE NEXT HOUR OR TWO.

DISCUSSION...TO THIS POINT...MODERATE BOUNDARY LAYER DESTABILIZATION
HAS BEEN MOSTLY CONFINED TO THE HIGHER TERRAIN TO THE WEST OF THE
RIO GRANDE RIVER /WEST THROUGH SOUTHWEST OF DEL RIO/ WHERE
INSOLATION AND MOIST UPSLOPE FLOW ARE CONTRIBUTING TO CAPE ON THE
ORDER OF 1000+ J/KG.  WITHIN THIS REGIME...STORMS HAVE ALREADY BEGUN
INITIATING ACROSS THE MOUNTAINS OF COAHUILA.

STORMS CLOSEST TO THE U.S. BORDER MAY AT LEAST APPROACH VAL VERDE
COUNTY BY 22-23Z...WHILE NEW CELLS CONTINUE TO GRADUALLY FORM TO THE
SOUTH SOUTHWEST.  MORE SUBSTANTIVE CONVECTIVE DEVELOPMENT NEAR AND
EAST OF THE RIVER MAY NOT OCCUR UNTIL THE 00-03Z TIME FRAME...AS AN
IMPULSE NOW PIVOTING INTO SOUTHWEST TEXAS CONTINUES ACROSS AND EAST
OF THE DAVIS MOUNTAINS AREA.  THIS MAY LARGELY BE FOCUSED WITHIN A
ZONE OF STRENGTHENING LOWER/MID TROPOSPHERIC WARM ADVECTION TO THE
EAST OF DEL RIO.  

ONCE THIS OCCURS...DESTABILIZATION EAST OF THE RIO GRANDE RIVER IS
EXPECTED TO BECOME SUFFICIENT TO SUPPORT ORGANIZED SEVERE
CONVECTION...IN THE PRESENCE OF STRONG SHEAR BENEATH 50+ KT WESTERLY
500 MB FLOW.  SUPERCELL STRUCTURES CAPABLE OF PRODUCING LARGE HAIL
AND DAMAGING WIND GUSTS WILL BE POSSIBLE.

..KERR/GOSS.. 04/12/2016

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

ATTN...WFO...EWX...SJT...MAF...

LAT...LON   29950201 30680147 31099969 30869887 29689902 28570000
            27540137 27690271 28830271 29950201

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 8:38 PM CDT	Mesoscale Discussion	SPC	Anderson, Angelina, Bowie, Camp, Cass, Cherokee and 22 more	67 min
Apr 12, 5:13 PM CDT	Mesoscale Discussion	SPC	Fort Bend, Harris, Liberty, Waller	3 hr

Nearby

Mesoscale Discussions in Texas, 2016 Every 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.