Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 788
The Storm Prediction Center issued this mesoscale discussion at May 11, 2012, 5:18 PM CDT for 46 counties in Texas. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- May 11, 2012, 5:18 PM CDT (22:18 UTC)
- Expired
- May 11, 2012, 6:45 PM CDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 46 counties
Anderson County, TX, Angelina County, TX, Austin County, TX, Bastrop County, TX, Bell County, TX, Blanco County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Cherokee County, TX, Colorado County, TX, Comal County, TX, Falls County, TX, Fayette County, TX, Fort Bend County, TX, Freestone County, TX, Gonzales County, TX, Grimes County, TX, Guadalupe County, TX, Harris County, TX, Hays County, TX, Henderson County, TX, Houston County, TX, Lavaca County, TX, Lee County, TX, Leon County, TX, Liberty County, TX, Limestone County, TX, Madison County, TX, Milam County, TX, Montgomery County, TX, Navarro County, TX, Polk County, TX, Rains County, TX, Robertson County, TX, San Jacinto County, TX, Smith County, TX, Travis County, TX, Trinity County, TX, Van Zandt County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Williamson County, TX, Wood County, TX
The radar
The Ft Hood radar (KGRK), 92 km from the middle of the area, began a volume at 22:19 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
Fort Worth, TX (KFWD), launched 12:00Z, 10.3 hours before the alert went out and 243 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.
- Mixed-layer CAPE
- 119 J/kg
- Mixed-layer CIN
- -9 J/kg
- Mixed-layer LCL
- 617 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 60 m²/s²
- 0-3 km storm-relative helicity
- 128 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted, in the capitals the NWS used until 2016.
653
ACUS11 KWNS 112218
SWOMCD
SPC MCD 112218
TXZ000-112345-
MESOSCALE DISCUSSION 0788
NWS STORM PREDICTION CENTER NORMAN OK
0518 PM CDT FRI MAY 11 2012
AREAS AFFECTED...PORTIONS OF CNTRL/ERN TX
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 112218Z - 112345Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...SOME SVR THREAT MAY EVOLVE INTO THIS EVENING. TRENDS WILL
CONTINUE TO BE MONITORED FOR THE POSSIBLE ISSUANCE OF A WW.
DISCUSSION...RELATIVELY ILL-DEFINED MESOSCALE SFC BOUNDARIES EAST OF
A MID/UPPER-LEVEL CLOSED LOW TRACKING ACROSS PORTIONS OF N TX AND OK
WILL CONTINUE TO SERVE AS FOCI FOR BANDS AND CLUSTERS OF DEEP
CONVECTION ACROSS PORTIONS OF CNTRL/ERN TX.
A BROKEN SQUALL LINE EXTENDING FROM 50 MILES NW OF TYLER TX TO 15
MILES ENE OF TEMPLE TX WILL CONTINUE TO EXHIBIT SOME SEWD
PROPAGATION ACROSS PORTIONS OF ERN TX DURING THE NEXT FEW HOURS AS
MARGINALLY UNSTABLE INFLOW -- MLCAPE VALUES OF 500-1000 J PER KG
ENHANCED IN POCKETS OF INSOLATION -- SUPPORTS REGENERATIVE
CONVECTION FARTHER SE. INVOF THE SQUALL LINE...EFFECTIVE BULK SHEAR
MAGNITUDES OF 25-35 KT WILL SUPPORT SOME CONVECTIVE ORGANIZATION
INCLUDING BOWING LINE SEGMENTS WITH POSSIBLE SVR WIND GUSTS.
HOWEVER...WEAK MID-LEVEL LAPSE RATES OWING TO EARLIER CONVECTIVE
OVERTURNING MAY MITIGATE UPDRAFT STRENGTH.
SOUTH OF THE SQUALL LINE TOWARD THE SAN ANTONIO AND HOUSTON
AREAS...MORE ISOLATED CONVECTION IS DEVELOPING INVOF SOMEWHAT
STRONGER DEEP-LAYER SHEAR -- I.E. EFFECTIVE BULK SHEAR MAGNITUDES OF
35-50 KT. RICHER LOW-LEVEL MOISTURE AND STEEPER LOW-LEVEL LAPSE
RATES IN THIS REGION ARE YIELDING COMPARATIVELY STRONGER BUOYANCY.
THIS MAY OCCASIONALLY SUPPORT ORGANIZED STORM STRUCTURES...WITH
ATTENDANT THREATS FOR DMGG WIND GUSTS AND SVR HAIL. HOWEVER...GIVEN
THAT THIS REGION IS REMOVED FROM THE STRONGER DCVA ASSOCIATED WITH
THE LOW...WEAK MID-LEVEL LAPSE RATES ARE FORECAST TO PERSIST...AND
THIS MAY MITIGATE THE OVERALL SVR THREAT.
..COHEN/CARBIN.. 05/11/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LCH...SHV...HGX...FWD...EWX...
LAT...LON 30979786 31829680 32909605 32829527 30999443 29949457
29499496 29079611 29319821 30199852 30979786SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 10, 7:18 PM CDT | Mesoscale Discussion | SPC | Aransas, Atascosa, Austin, Bastrop, Bee, Bexar and 43 more | 57 min |
| May 10, 7:50 PM CDT | Tornado Watch | SPC | Aransas, Atascosa, Austin, Bastrop, Bee, Bell and 48 more | 9 hr |
| May 10, 9:42 PM CDT | Mesoscale Discussion | SPC | Aransas, Atascosa, Austin, Bastrop, Bee, Bell and 36 more | 63 min |
| May 10, 11:36 PM CDT | Mesoscale Discussion | SPC | Aransas, Brooks, Calhoun, Cameron, Hidalgo, Jackson and 13 more | 84 min |
| May 11, 1:40 AM CDT | Mesoscale Discussion | SPC | Aransas, Austin, Bee, Brazoria, Brooks, Calhoun and 25 more | 65 min |
| May 11, 2:41 AM CDT | Mesoscale Discussion | SPC | Cameron, Chambers, Galveston, Hidalgo, Jefferson, Kenedy and 3 more | 34 min |
| May 11, 1:22 PM CDT | Mesoscale Discussion | SPC | Anderson, Bosque, Camp, Cherokee, Collin, Cooke and 28 more | 53 min |
| May 11, 2:13 PM CDT | Mesoscale Discussion | SPC | Atascosa, Austin, Bandera, Bastrop, Bell, Bexar and 41 more | 2 hr |
| May 11, 5:51 PM CDT | Mesoscale Discussion | SPC | Bee, Brooks, Duval, Goliad, Hidalgo, Jim Hogg and 7 more | 84 min |
Nearby
Mesoscale Discussions in Texas, 2012Every 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.