Alert archive / Texas / Mesoscale Discussions in 2013
Mesoscale Discussion 749
The Storm Prediction Center issued this mesoscale discussion at May 21, 2013, 10:09 AM CDT for 63 counties in Texas. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- May 21, 2013, 10:09 AM CDT (15:09 UTC)
- Expired
- May 21, 2013, 11:45 AM CDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 95%
All 63 counties
Anderson County, TX, Bosque County, TX, Bowie County, TX, Brown County, TX, Callahan County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Coleman County, TX, Collin County, TX, Comanche County, TX, Cooke County, TX, Coryell County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Eastland County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Franklin County, TX, Freestone County, TX, Grayson County, TX, Gregg County, TX, Hamilton County, TX, Harrison County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Houston County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Leon County, TX, Limestone County, TX, Marion County, TX, McLennan County, TX, Mills County, TX, Morris County, TX, Nacogdoches County, TX, Navarro County, TX, Palo Pinto County, TX, Panola County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Rusk County, TX, Shackelford County, TX, Smith County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Taylor County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wise County, TX, Wood County, TX, Young County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 57 km from the middle of the area, began a volume at 15:10 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, 3.2 hours before the alert went out and 70 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
- 1513 J/kg
- Mixed-layer CIN
- -271 J/kg
- Mixed-layer LCL
- 793 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 316 m²/s²
- 0-3 km storm-relative helicity
- 251 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.6
The text
As transmitted, in the capitals the NWS used until 2016.
982
ACUS11 KWNS 211509
SWOMCD
SPC MCD 211509
TXZ000-ARZ000-OKZ000-211645-
MESOSCALE DISCUSSION 0749
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CDT TUE MAY 21 2013
AREAS AFFECTED...MUCH OF NRN TX
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 211509Z - 211645Z
PROBABILITY OF WATCH ISSUANCE...95 PERCENT
SUMMARY...STORMS WILL INCREASE IN COVERAGE AND INTENSITY OVER THE
NEXT 1-2 HRS...AND PARTICULARLY DAMAGING WINDS ARE EXPECTED TO
AFFECT MUCH OF NRN TX. IN ADDITION...A FEW TORNADOES AND VERY LARGE
HAIL WILL ALL BE POSSIBLE. A WATCH WILL BE ISSUED SHORTLY.
DISCUSSION...AN OUTFLOW BOUNDARY CURRENTLY EXTENDS FROM WRN AR WWD
ALONG THE RED RIVER TO JUST W OF ABILENE TX...JOINING WITH A
DEVELOPING COLD FRONT WHICH WILL CONTINUE SWD ACROSS W TX. TO THE
E...AN EXTREMELY MOIST AND UNSTABLE ATMOSPHERE WAS IN PLACE...WITH
MIDLEVEL LAPSE RATES OF 8.0-9.0 C/KM.
STORMS WILL RAPIDLY DEVELOP ALONG THE ADVANCING COLD FRONT WHICH
ALSO INTERSECTS THE OUTFLOW BOUNDARY IN THE NEXT FEW HOURS...AND ARE
EXPECTED TO QUICKLY GROW UPSCALE INTO A DAMAGING MCS. WIND GUSTS
OVER HURRICANE FORCE...WIND DRIVEN HAIL...AND A FEW TORNADOES WILL
BE POSSIBLE AS THE SYSTEM MATURES AND FORWARD PROPAGATES ACROSS A
LARGE PART OF NRN TX AND INTO THE ARKLATEX THIS EVENING.
ALTHOUGH MAINLY A LINEAR STORM MODE IS EVENTUALLY EXPECTED...INITIAL
DEVELOPMENT MAY BE SUPERCELLS WITH AN ENHANCED TORNADO THREAT. WHEN
STORMS DO MERGE...THERE WILL LIKELY BE AREAS OF ROTATION EMBEDDED
WITHIN THE ADVANCING LINE...PERHAPS PRODUCING SWATHS OF PARTICULARLY
DAMAGING WINDS.
..JEWELL/KERR.. 05/21/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...SHV...TSA...HGX...FWD...OUN...SJT...
LAT...LON 31970006 32929962 33939680 33899492 33579436 33179426
32169421 31459469 31169556 31329716 31479905 31970006SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 8:45 PM CDT | Mesoscale Discussion | SPC | Bosque, Brown, Burnet, Callahan, Clay, Coleman and 37 more | 60 min |
| May 21, 8:12 AM CDT | Mesoscale Discussion | SPC | Archer, Clay, Collin, Cooke, Delta, Denton and 9 more | 93 min |
| May 21, 10:26 AM CDT | Tornado Watch | SPC | Anderson, Archer, Baylor, Bell, Bosque, Brown and 58 more | 10 hr |
| May 21, 10:45 AM CDT | Severe Thunderstorm Watch | SPC | Foard, Hardeman, Knox, Wichita, Wilbarger | 6 hr |
| May 21, 1:19 PM CDT | Mesoscale Discussion | SPC | Anderson, Bosque, Brown, Collin, Comanche, Concho and 38 more | 116 min |
| May 21, 1:35 PM CDT | Mesoscale Discussion | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Delta and 17 more | 115 min |
| May 21, 1:50 PM CDT | Tornado Watch | SPC | Angelina, Bowie, Camp, Cass, Cherokee, Franklin and 15 more | 8 hr |
| May 21, 3:18 PM CDT | Mesoscale Discussion | SPC | Anderson, Bosque, Bowie, Camp, Cass, Cherokee and 39 more | 87 min |
| May 21, 4:55 PM CDT | Mesoscale Discussion | SPC | Brazos, Burleson, Houston, Madison, Trinity, Walker | 95 min |
| May 21, 5:54 PM CDT | Mesoscale Discussion | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Gregg and 11 more | 66 min |
| May 21, 6:55 PM CDT | Severe Thunderstorm Watch | SPC | Brazos, Burleson, Grimes, Hardin, Houston, Jasper and 9 more | 6 hr |
Nearby
Mesoscale Discussions in Texas, 2013Every mesoscale discussion in 2013
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.