Alert archive / Texas / Mesoscale Discussions in 2011
Mesoscale Discussion 508
The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2011, 5:10 PM CDT for 27 counties in Texas. It was in force for 65 min.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2011, 5:10 PM CDT (22:10 UTC)
- Expired
- Apr 21, 2011, 6:15 PM CDT
- In force
- 65 min
- Issued by
- the Storm Prediction Center
All 27 counties
Borden County, TX, Brewster County, TX, Coke County, TX, Crockett County, TX, Fisher County, TX, Glasscock County, TX, Haskell County, TX, Howard County, TX, Irion County, TX, Jones County, TX, Kent County, TX, Midland County, TX, Mitchell County, TX, Nolan County, TX, Pecos County, TX, Reagan County, TX, Runnels County, TX, Schleicher County, TX, Scurry County, TX, Shackelford County, TX, Sterling County, TX, Stonewall County, TX, Taylor County, TX, Terrell County, TX, Tom Green County, TX, Upton County, TX, Val Verde County, TX
The radar
The San Angelo radar (KSJT), 78 km from the middle of the area, began a volume at 22:11 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
Midland Regional, TX (KMAF), launched 12:00Z, 10.2 hours before the alert went out and 97 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
- 695 J/kg
- Mixed-layer CIN
- -359 J/kg
- Mixed-layer LCL
- 968 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 240 m²/s²
- 0-3 km storm-relative helicity
- 283 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.4
The text
As transmitted, in the capitals the NWS used until 2016.
462
ACUS11 KWNS 212211
SWOMCD
SPC MCD 212210
TXZ000-212315-
MESOSCALE DISCUSSION 0508
NWS STORM PREDICTION CENTER NORMAN OK
0510 PM CDT THU APR 21 2011
AREAS AFFECTED...TRANS-PECOS REGION AND THE ERN PERMIAN BASIN OF W
TX
CONCERNING...SEVERE THUNDERSTORM WATCH 176...
VALID 212210Z - 212315Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 176
CONTINUES.
VISIBLE SATELLITE TRENDS INDICATE A LONE RIGHT-MOVING SUPERCELL
LOCATED 30 SE FST...WHILE IN RECENT SCANS AN AGITATED TOWERING CU
FIELD HAS DEVELOPED NEAR THE DRYLINE-WARM FRONT INTERSECTION
APPROXIMATELY 30 ENE BGS. THIS CONVECTION IS DEVELOPING WITHIN A
HOT/RELATIVELY MOIST AIR MASS /WITH ML CAPE VALUES EXCEEDING 3000
J/KG ACROSS SRN PORTIONS OF THE WATCH/. THE PRIMARY THREATS WITH
THESE THUNDERSTORMS WILL CONTINUE TO BE STRONG WIND GUSTS AND VERY
LARGE HAIL...GIVEN THE PRESENCE OF A HOT/WELL-MIXED BOUNDARY LAYER
AND STEEP MIDLEVEL LAPSE RATES. LARGE SFC T-TD SPREADS /30-40 DEG F/
SHOULD TEND TO LIMIT THE THREAT FOR TORNADOES...BUT WITH FAVORABLE
VEERING LOW-LEVEL SHEAR PROFILES THE POTENTIAL FOR A ROGUE TORNADO
CANNOT BE RULED OUT. WEAK DEEP-LAYER FORCING AND THE PRESENCE OF A
CAPPING INVERSION ABOVE 850 MB SHOULD CONTINUE TO FAVOR DISCRETE
CONVECTIVE MODE.
..ROGERS.. 04/21/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...OUN...EWX...SJT...LUB...MAF...
LAT...LON 29740113 29740329 30490305 31430229 32930141 33260108
33500009 33379947 32959913 29740113SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 7:00 PM CDT | Mesoscale Discussion | SPC | Archer, Callahan, Coleman, Eastland, Jack, Palo Pinto and 5 more | 60 min |
| Apr 21, 2:19 PM CDT | Mesoscale Discussion | SPC | Coke, Crane, Crockett, Fisher, Glasscock, Howard and 16 more | 56 min |
| Apr 21, 3:03 PM CDT | Severe Thunderstorm Watch | SPC | Borden, Brewster, Brown, Callahan, Coke, Coleman and 23 more | 7 hr |
| Apr 21, 3:23 PM CDT | Mesoscale Discussion | SPC | Camp, Collin, Cooke, Dallas, Delta, Denton and 25 more | 67 min |
Nearby
Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011
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.