Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 237

March 18, 201614 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2016, 1:57 PM CDT for 14 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2016, 1:57 PM CDT (18:57 UTC)
Expired
Mar 18, 2016, 4:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
60%

Counties Bandera County, TX, Crockett County, TX, Edwards County, TX, Gillespie County, TX, Kendall County, TX, Kerr County, TX, Kinney County, TX, Maverick County, TX, Medina County, TX, Real County, TX, Sutton County, TX, Terrell County, TX, Uvalde County, TX, Val Verde County, TX

The radar

The Laughlin AFB radar (KDFX), 18 km from the middle of the area, began a volume at 18:59 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

Del Rio, TX (KDLF), launched 12:00Z, 7.0 hours before the alert went out and 38 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.

140 
ACUS11 KWNS 181857
SWOMCD
SPC MCD 181857 
TXZ000-182100-

MESOSCALE DISCUSSION 0237
NWS STORM PREDICTION CENTER NORMAN OK
0157 PM CDT FRI MAR 18 2016

AREAS AFFECTED...THE TEXAS EDWARDS PLATEAU/HILL COUNTRY AND ADJACENT
RIO GRANDE VALLEY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 181857Z - 182100Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...SCATTERED STRONG TO SEVERE STORM DEVELOPMENT APPEARS
POSSIBLE ACROSS THE REGION THROUGH THE 20-00Z TIME FRAME.  STRONGEST
ACTIVITY LIKELY WILL BE CAPABLE OF PRODUCING LARGE HAIL AND LOCALLY
STRONG WIND GUSTS.  A WATCH MAY BE NEEDED AS EARLY AS THE NEXT HOUR
OR TWO.

DISCUSSION...LIGHT SOUTHEASTERLY SURFACE FLOW UP THE RIO GRANDE
VALLEY...AND INTO THE EDWARDS PLATEAU/HILL COUNTRY...AS WELL AS
HIGHER TERRAIN WEST OF THE RIO GRANDE RIVER...IS MAINTAINING HIGH
BOUNDARY LAYER MOISTURE CONTENT IN ADVANCE OF A SOUTHWARD ADVANCING
COLD FRONT.  AND INSOLATION BENEATH WARM/CAPPING ELEVATED MIXED
LAYER AIR IS CONTRIBUTING TO THE DEVELOPMENT OF MODERATE TO STRONG
POTENTIAL INSTABILITY.  

THUNDERSTORMS HAVE ALREADY INITIATED OFF THE MOUNTAINS WEST OF THE
RIVER /ABOUT 75 MI WSW OF DEL RIO/...BUT INHIBITION OTHERWISE
REMAINS STRONG FOR BOUNDARY LAYER BASED DEVELOPMENT.  GIVEN THE
GENERALLY LIGHT NATURE OF THE DEEP LAYER WESTERLY MEAN FLOW...IT MAY
TAKE SOME TIME FOR CONVECTION WEST OF THE RIVER TO PROPAGATE OFF THE
HIGHER TERRAIN AND CROSS THE RIVER INTO SOUTH TEXAS.  GUIDANCE IS
SUGGESTIVE THAT THIS MAY NOT BE UNTIL EARLY EVENING.  HOWEVER...THE
HIGH RESOLUTION RAPID REFRESH...AMONG OTHER MODEL OUTPUT...HAS BEEN
SUGGESTIVE THAT THE STORM INITIATION COULD OCCUR ACROSS THE EDWARDS
PLATEAU/HILL COUNTRY AS EARLY AS 20-21Z.

IT APPEARS AT LEAST POSSIBLE THAT FORCING ASSOCIATED WITH SOUTHWARD
PROPAGATING GRAVITY WAVES EVIDENT IN SATELLITE IMAGERY COULD
CONTRIBUTE TO SUFFICIENT WEAKENING OF INHIBITION TO ALLOW STORMS TO
DEVELOP.  IF THIS OCCURS...THE THERMODYNAMIC ENVIRONMENT APPEARS
MORE THAN SUPPORTIVE OF SEVERE STORMS CAPABLE OF PRODUCING LARGE
HAIL...AND AT LEAST LOCALLY STRONG WIND GUSTS LATE THIS AFTERNOON.

..KERR/WEISS.. 03/18/2016

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

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

LAT...LON   29570222 30220226 30880179 30439977 30539894 29889825
            29249888 28760004 28109986 27099959 27099959 27620159
            29570222

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, 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
Mar 18, 6:05 PM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bell, Bexar, Blanco and 23 more55 min

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.