Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 642

May 17, 20165 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 17, 2016, 5:18 PM CDT for 5 counties in Texas. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: May 17, 2016, 5:18 PM CDT (22:18 UTC)
Expired: May 17, 2016, 6:15 PM CDT
In force: 57 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Bee County, TX, Duval County, TX, Jim Wells County, TX, Live Oak County, TX, Webb County, TX

The radar

The Corpus Christi radar (KCRP), 130 km from the middle of the area, began a volume at 22:18 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 181May 17, 6:20 PM CDT

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 10.3 hours before the alert went out and 148 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: 2359 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 536 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

516 
ACUS11 KWNS 172218
SWOMCD
SPC MCD 172218 
TXZ000-172315-

MESOSCALE DISCUSSION 0642
NWS STORM PREDICTION CENTER NORMAN OK
0518 PM CDT TUE MAY 17 2016

AREAS AFFECTED...SOUTH TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 172218Z - 172315Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THUNDERSTORMS ARE DEVELOPING ALONG A SWD MOVING BOUNDARY
AND MAY POSE ISOLATED THREATS FOR LARGE HAIL AND STRONG WIND GUSTS
THIS EVENING. THE COVERAGE OF THESE THREATS MAY REMAIN LIMITED IN
THE SHORT-TERM...BUT TRENDS WILL CONTINUE TO BE MONITORED FOR A
POSSIBLE WATCH.

DISCUSSION...INCREASING TOWERING CU/CB DEVELOPMENT HAS BEEN NOTED
WITHIN THE PAST 1-2 HRS ALONG A SWD MOVING BOUNDARY...WHICH WAS
LOCATED JUST S OF A LINE FROM CUT TO BEA AS OF 22Z. ADDITIONAL TSTMS
HAVE DEVELOPED FARTHER W OVER THE HIGHER TERRAIN OF MEXICO...AND
CURRENT MOTION SUGGESTS THESE SHOULD REMAIN W OF THE RIO GRANDE FOR
AT LEAST THE NEXT COUPLE HRS.

CURRENT RADAR TRENDS SUGGEST MORE RECENT TSTM DEVELOPMENT ALONG THE
BOUNDARY IS MOVING NWD TOWARDS SLIGHTLY COOLER AIR. THE POTENTIAL
FOR LARGE HAIL AND LOCALLY DMGG WIND GUSTS...ENHANCED BY THE
PRESENCE OF STEEP LAPSE RATES ALOFT AND MLCAPE VALUES EXCEEDING 3000
J/KG...WILL BE MAXIMIZED WITH ANY STORM THAT CAN ANCHOR ALONG OR
REMAIN S OF THE BOUNDARY...WHERE TEMPERATURES HAVE HEATED INTO THE
LOW 90S. WEAK BUT VEERING LOW-LEVEL FLOW BENEATH MODERATELY STRONG
MIDLEVEL WLYS /AS SAMPLED BY 19Z CRP RAOB/ IS SUFFICIENT TO SUPPORT
MARGINAL SUPERCELL STRUCTURES/ORGANIZED CLUSTERS. A BRIEF/WEAK
TORNADO CANNOT BE RULED OUT WITH ANY SUSTAINED STORM INTERACTING
FAVORABLY WITH THE BOUNDARY...BUT OTHERWISE THIS THREAT SHOULD
REMAIN LIMITED.

..ROGERS/THOMPSON.. 05/17/2016

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

ATTN...WFO...CRP...

LAT...LON   28639779 28309760 27669781 27549964 27930014 28040007
            28129933 28319880 28639779

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 16, 7:23 PM CDT	Mesoscale Discussion	SPC	Carson, Collingsworth, Gray, Hansford, Hartley, Hemphill and 7 more	67 min
May 16, 11:58 PM CDT	Severe Thunderstorm Watch	SPC	Archer, Baylor, Briscoe, Childress, Clay, Cottle and 7 more	5 hr
May 17, 2:08 AM CDT	Mesoscale Discussion	SPC	Clay, Cooke, Foard, Hardeman, Montague, Wichita and 1 more	2 hr
May 17, 1:52 PM CDT	Mesoscale Discussion	SPC	Bandera, Crane, Crockett, Edwards, Irion, Kerr and 8 more	113 min
May 17, 2:25 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bexar, Blanco, Brewster, Comal and 34 more	13 hr
May 17, 5:38 PM CDT	Mesoscale Discussion	SPC	Bandera, Crockett, Dimmit, Edwards, Frio, Gillespie and 17 more	97 min
May 17, 6:20 PM CDT	Severe Thunderstorm Watch	SPC	Brooks, Duval, Hidalgo, Jim Hogg, La Salle, McMullen and 3 more	5 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.