Alert archive / Texas / Mesoscale Discussions in 2011

Mesoscale Discussion 481

April 19, 20119 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2011, 9:03 PM CDT for 9 counties in Texas. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Apr 19, 2011, 9:03 PM CDT (02:03 UTC)
Expired
Apr 19, 2011, 10:00 PM CDT
In force
57 min
Issued by
the Storm Prediction Center

Counties Bell County, TX, Coryell County, TX, Falls County, TX, Freestone County, TX, Henderson County, TX, Hill County, TX, Limestone County, TX, McLennan County, TX, Navarro County, TX

The radar

The Ft Hood radar (KGRK), 107 km from the middle of the area, began a volume at 02:04 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

Fort Worth, TX (KFWD), launched 00:00Z, 2.1 hours before the alert went out and 135 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 00:00Z on 2011-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2011-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -127 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3240 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
-127 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

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

777 
ACUS11 KWNS 200203
SWOMCD
SPC MCD 200203 
TXZ000-200300-

MESOSCALE DISCUSSION 0481
NWS STORM PREDICTION CENTER NORMAN OK
0903 PM CDT TUE APR 19 2011

AREAS AFFECTED...SRN PORTIONS OF N-CNTRL TX

CONCERNING...SEVERE THUNDERSTORM WATCH 156...

VALID 200203Z - 200300Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 156
CONTINUES.

THREAT FOR ISOLATED LARGE HAIL MAY PERSIST FOR ANOTHER 30 MINUTES TO
AN HOUR WITH LONE SUPERCELL JUST SOUTH OF ITASCA. ONCE THIS STORM
DIMINISHES ADDITIONAL DEVELOPMENT APPEARS UNLIKELY.

LONE SUPERCELL STORM THAT DEVELOPED EARLIER ALONG THE DRYLINE-COLD
FRONT MERGER APPEARS TO BE WEAKENING. INCREASING CONVECTIVE
INHIBITION RESULTING FROM A STABILIZING BOUNDARY LAYER AND WEAKENING
CONVERGENCE ALONG STALLED BOUNDARY SUGGEST ADDITIONAL DEVELOPMENT IS
UNLIKELY ONCE THIS STORM DISSIPATES. PRIOR TO DISSIPATION...THE
STORM WILL REMAIN CAPABLE OF PRODUCING ISOLATED LARGE HAIL AND
PERHAPS DOWNBURST WINDS.

..DIAL.. 04/20/2011

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

ATTN...WFO...FWD...EWX...

LAT...LON   31369810 31839771 32079715 32289603 32239560 31739585
            30879678 30989793 31369810

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 19, 7:47 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Delta, Franklin, Hopkins and 11 more88 min
Apr 19, 11:17 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Franklin, Gregg, Harrison and 7 more58 min
Apr 19, 11:45 PM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Franklin, Gregg, Harrison and 6 more3 hr
Apr 20, 12:46 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Franklin, Marion, Morris and 2 more89 min
Apr 20, 1:52 PM CDTMesoscale DiscussionSPCBell, Bosque, Brown, Burnet, Coleman, Comanche and 21 more53 min
Apr 20, 2:04 PM CDTSevere Thunderstorm WatchSPCBowie, Red River7 hr
Apr 20, 2:21 PM CDTSevere Thunderstorm WatchSPCBandera, Bell, Blanco, Burnet, Concho, Coryell and 20 more8 hr
Apr 20, 5:47 PM CDTMesoscale DiscussionSPCBlanco, Burnet, Concho, Crockett, Edwards, Gillespie and 15 more58 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.