Alert archive / Texas / Mesoscale Discussions in 2016

Mesoscale Discussion 511

April 30, 201613 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2016, 5:12 AM CDT for 13 counties in Texas. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
Apr 30, 2016, 5:12 AM CDT (10:12 UTC)
Expired
Apr 30, 2016, 6:45 AM CDT
In force
93 min
Issued by
the Storm Prediction Center
Chance of a watch
60%

Counties Austin County, TX, Burleson County, TX, Colorado County, TX, Fayette County, TX, Grimes County, TX, Harris County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Montgomery County, TX, San Jacinto County, TX, Waller County, TX, Washington County, TX

The radar

The Houston radar (KHGX), 116 km from the middle of the area, began a volume at 10:15 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 10.2 hours before the alert went out and 272 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, Lake Charles Mun, LA at 00:00Z on 2016-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1365 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lake Charles Mun, LA at 00:00Z on 2016-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 square meters per square second.19395878Sfc1 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
1365 J/kg
Mixed-layer CIN
-102 J/kg
Mixed-layer LCL
717 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.7

Open this sounding in Storm Lab

The text

As transmitted.

303 
ACUS11 KWNS 301012
SWOMCD
SPC MCD 301012 
TXZ000-301145-

MESOSCALE DISCUSSION 0511
NWS STORM PREDICTION CENTER NORMAN OK
0512 AM CDT SAT APR 30 2016

AREAS AFFECTED...SOUTHEAST TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 301012Z - 301145Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...EARLIER SUPERCELL THAT HAS EVOLVED INTO A SHORT-LINE
SEGMENT ACROSS SOUTH-CENTRAL TX MAY CONTINUE TO POSE A RISK FOR
ISOLATED SEVERE WIND/HAIL AS IT TRACKS ALONG THE LARGE-SCALE OUTFLOW
BOUNDARY IN THE WAKE OF THE SOUTHEAST TX MCS.

DISCUSSION...CLASSIC SUPERCELL EVOLUTION INTO A SMALL-SCALE BOW ECHO
OCCURRED IN THE AUSTIN VICINITY WITH A MEASURED WIND GUSTS TO 52 KT
AT 0953Z. THIS BOW STRUCTURE APPEARS TO BE ASSOCIATED WITH A MESOLOW
EVIDENT IN 10Z SURFACE OBSERVATIONS AND MAY RIDE ALONG A REMNANT
WEST-EAST/ORIENTED OUTFLOW BOUNDARY THAT ARCS ACROSS COLLEGE STATION
INTO SOUTHEAST TX. WITH AMBIENT WARM SECTOR AIR MASS STILL
CHARACTERIZED BY MIDDLE 70S SURFACE DEW POINTS...A SWATH OF SEVERE
WIND/HAIL MAY ACCOMPANY THIS ACTIVITY FOR AT LEAST THE NEXT 2-3
HOURS.

..GRAMS/GOSS.. 04/30/2016

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

ATTN...WFO...HGX...EWX...

LAT...LON   30369724 30579676 30679602 30689534 30579493 30279482
            29889471 29709482 29569607 29369697 29449740 30369724

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 8:07 PM CDTMesoscale DiscussionSPCBandera, Bastrop, Bell, Bexar, Blanco, Bosque and 29 more83 min
Apr 29, 8:20 PM CDTSevere Thunderstorm WatchSPCBandera, Bastrop, Bexar, Blanco, Burnet, Caldwell and 19 more9 hr
Apr 29, 8:56 PM CDTMesoscale DiscussionSPCAnderson, Angelina, Bowie, Brazos, Burleson, Camp and 34 more94 min
Apr 29, 9:58 PM CDTSevere Thunderstorm WatchSPCAnderson, Angelina, Bell, Bowie, Brazos, Burleson and 47 more7 hr
Apr 29, 11:42 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Gregg, Harrison, Marion and 4 more93 min
Apr 30, 1:46 AM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Comal, Hays, Kendall and 3 more59 min
Apr 30, 3:23 AM CDTMesoscale DiscussionSPCHardin, Harris, Jasper, Jefferson, Liberty, Newton and 7 more97 min
Apr 30, 5:11 AM CDTSevere Thunderstorm WatchSPCHardin, Jasper, Jefferson, Newton, Orange, Sabine and 1 more9 hr
Apr 30, 5:27 AM CDTSevere Thunderstorm WatchSPCAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 11 more6 hr
Apr 30, 7:38 AM CDTMesoscale DiscussionSPCChambers, Fort Bend, Hardin, Harris, Jefferson, Liberty and 1 more67 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.