Alert archive / Texas / Mesoscale Discussions in 2012

Mesoscale Discussion 771

May 9, 2012Hidalgo County, Kenedy County, Willacy County, Texas

The Storm Prediction Center issued this mesoscale discussion at May 9, 2012, 10:09 PM CDT for Hidalgo County, Kenedy County, Willacy County, Texas. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 9, 2012, 10:09 PM CDT (03:09 UTC)
Expired: May 9, 2012, 11:15 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Hidalgo County, TX, Kenedy County, TX, Willacy County, TX

The radar

The Brownsville radar (KBRO), 86 km from the middle of the area, began a volume at 03:09 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

Brownsville Intl, TX (KBRO), launched 00:00Z, 3.2 hours before the alert went out and 89 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: 2929 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 482 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -5 m²/s²
0-3 km storm-relative helicity: -12 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

266 
ACUS11 KWNS 100309
SWOMCD
SPC MCD 100309 
TXZ000-100415-

MESOSCALE DISCUSSION 0771
NWS STORM PREDICTION CENTER NORMAN OK
1009 PM CDT WED MAY 09 2012

AREAS AFFECTED...SRN TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 100309Z - 100415Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A LARGE HAIL AND WIND DAMAGE THREAT IS LIKELY TO CONTINUE
ACROSS SOUTH TX LATE THIS EVENING. HOWEVER...THE SEVERE THREATS ARE
EXPECTED TO REMAIN VERY ISOLATED AND WW ISSUANCE IS NOT EXPECTED.

DISCUSSION...AN ISOLATED SEVERE THUNDERSTORM IS ONGOING ABOUT 50
MILES NORTHWEST OF BROWNSVILLE ALONG THE NWRN EDGE OF MODERATE TO
STRONG INSTABILITY. THE 00Z SOUNDING IN BROWNSVILLE EARLIER THIS
EVENING SHOWED MUCAPE APPROACHING 4000 J/KG. THIS ALONG WITH STEEP
LAPSE RATES IS SUPPORTING A THREAT FOR LARGE HAIL. IN ADDITION...SFC
DEWPOINTS IN THE LOWER 70S F AND PRECIPITABLE WATER VALUES ABOVE 2.0
INCHES IS LIKELY CONTRIBUTING TO PRECIP LOADING WITH AN POTENTIAL
FOR ISOLATED DAMAGING WIND GUSTS. WATER VAPOR IMAGERY CURRENTLY
SHOWS A SHORTWAVE TROUGH OVER NRN MEXICO BUT THIS FEATURE IS LIKELY
TOO FAR TO THE SOUTHWEST TO SUPPORT THE THUNDERSTORM ACTIVITY IN
SOUTH TX. FOR THIS REASON...THE THREAT FOR LARGE HAIL IS EXPECTED TO
REMAIN VERY ISOLATED AND WILL PROBABLY ONLY PERSIST FOR ANOTHER HOUR
OR TWO.

..BROYLES.. 05/10/2012

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

ATTN...WFO...BRO...

LAT...LON   27039790 26899820 26709836 26479839 26289833 26169804
            26139782 26209751 26299739 26639732 27019746 27039790

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 10, 5:27 AM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Brooks, Dimmit, Duval, Edwards and 19 more	2 hr
May 10, 5:42 AM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bee, Bexar, Brooks, Cameron and 36 more	7 hr
May 10, 9:51 AM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bee, Bexar, Brooks, Cameron and 39 more	114 min
May 10, 11:40 AM CDT	Tornado Watch	SPC	Aransas, Atascosa, Bee, Brooks, Calhoun, Cameron and 27 more	8 hr
May 10, 11:52 AM CDT	Mesoscale Discussion	SPC	Bandera, Bexar, Blanco, Brown, Coke, Coleman and 24 more	53 min
May 10, 12:32 PM CDT	Severe Thunderstorm Watch	SPC	Bandera, Bastrop, Bexar, Blanco, Burnet, Caldwell and 25 more	7 hr
May 10, 2:07 PM CDT	Mesoscale Discussion	SPC	Aransas, Atascosa, Bee, Brooks, DeWitt, Dimmit and 19 more	113 min
May 10, 3:04 PM CDT	Mesoscale Discussion	SPC	Bandera, Bastrop, Bexar, Blanco, Burnet, Caldwell and 18 more	116 min
May 10, 5:21 PM CDT	Mesoscale Discussion	SPC	Crockett, Edwards, Sutton, Terrell, Val Verde	54 min
May 10, 5:43 PM CDT	Mesoscale Discussion	SPC	Aransas, Atascosa, Bee, Brooks, Cameron, DeWitt and 23 more	2 hr

Nearby

Mesoscale Discussions in Texas, 2012 Every mesoscale discussion in 2012

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.