Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 2189

September 18, 2011Love County, Oklahoma; 52 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 18, 2011, 3:59 PM CDT for Love County, Oklahoma; 52 counties in Texas. It was in force for 31 min.

The area

The outline as issued.

The facts

Issued
Sep 18, 2011, 3:59 PM CDT (20:59 UTC)
Expired
Sep 18, 2011, 4:30 PM CDT
In force
31 min
Issued by
the Storm Prediction Center
All 53 counties

Love County, OK, Bosque County, TX, Brown County, TX, Callahan County, TX, Coleman County, TX, Collin County, TX, Comanche County, TX, Concho 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, Grayson County, TX, Hamilton County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Lampasas County, TX, McCulloch County, TX, McLennan County, TX, Menard County, TX, Mills County, TX, Montague County, TX, Navarro County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Rockwall County, TX, Runnels County, TX, San Saba County, TX, Shackelford County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Van Zandt County, TX, Wise County, TX, Wood County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 89 km from the middle of the area, began a volume at 21:01 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, 9.0 hours before the alert went out and 113 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, Fort Worth, TX at 12:00Z on 2011-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 581 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 12:00Z on 2011-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
581 J/kg
Mixed-layer CIN
-136 J/kg
Mixed-layer LCL
1222 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

380 
ACUS11 KWNS 182100
SWOMCD
SPC MCD 182059
OKZ000-TXZ000-182130-

MESOSCALE DISCUSSION 2189
NWS STORM PREDICTION CENTER NORMAN OK
0359 PM CDT SUN SEP 18 2011

AREAS AFFECTED...NRN/CNTRL TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 182059Z - 182130Z

THUNDERSTORM DEVELOPMENT IS POSSIBLE OVER PORTIONS OF NRN/CNTRL TX
DURING THE NEXT FEW HRS. ENVIRONMENT SUPPORTS SVR STORMS POSING A
THREAT OF LARGE HAIL AND DAMAGING WINDS. WW IS LIKELY.

AT 20Z...SURFACE COLD FRONT EXTENDED SWWD FROM NERN OK INTO PORTIONS
OF CNTRL TX. RECENT VIS SATELLITE IMAGERY SHOWS GENERALLY FLAT CU
FIELD ALONG/AHEAD OF THE FRONT...WITH THE EXCEPTION OF A FEW
TOWERING CUMULUS NEAR THE RED RIVER. THOUGH BOUNDARY LAYER HAS
SLOWLY DESTABILIZED DURING THE AFTERNOON...UPPER VORT LOBE IS
SITUATED IMMEDIATELY ABOVE THE REGION...LEADING TO NEGLIGIBLE
LARGE-SCALE ASCENT. THUS...THUNDERSTORM INITIATION AND SUBSEQUENT
COVERAGE IS UNCERTAIN ATTM DURING THE SHORT TERM.
NEVERTHELESS...ENVIRONMENT IS QUITE MOIST AND UNSTABLE...WITH MLCAPE
VALUES NEAR 2500 J/KG. THIS INSTABILITY COMBINED WITH MODEST
VERTICAL SHEAR PROFILES WOULD BE SUFFICIENT FOR SVR MULTICELL
THUNDERSTORMS...POSING A LARGE HAIL AND DAMAGING WIND THREAT. GIVEN
RECENT TRENDS IN VIS SATELLITE IMAGERY...AREA MAY REQUIRE A WW
DURING THE NEXT HR.

..GARNER.. 09/18/2011

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

ATTN...WFO...SHV...TSA...FWD...OUN...EWX...SJT...

LAT...LON   31700069 33189925 33989738 33939504 32609508 30859835
            30730024 31700069

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 10:17 PM CDTMesoscale DiscussionSPCAtoka, Bryan, Carter, Cherokee, Cleveland, Coal and 28 more88 min
Sep 18, 2:45 PM CDTMesoscale DiscussionSPCAdair, Atoka, Cherokee, Craig, Delaware, Haskell and 14 more2 hr
Sep 18, 3:30 PM CDTSevere Thunderstorm WatchSPCAdair, Atoka, Bryan, Carter, Cherokee, Choctaw and 24 more8 hr
Sep 18, 5:41 PM CDTSevere Thunderstorm WatchSPCMcCurtain7 hr
Sep 18, 6:48 PM CDTMesoscale DiscussionSPCAdair, Atoka, Bryan, Cherokee, Choctaw, Coal and 20 more57 min
Sep 18, 4:06 PM CDTSevere Thunderstorm WatchSPCAnderson, Bosque, Brown, Callahan, Coke, Coleman and 51 more9 hr
Sep 18, 6:18 PM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Comal, Edwards, Hays and 6 more57 min

Nearby

Mesoscale Discussions in Texas, 2011Mesoscale Discussions in Oklahoma, 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.