Alert archive / Texas / Mesoscale Discussions in 2004

Mesoscale Discussion 280

April 6, 2004Beauregard Parish, Calcasieu Parish, Louisiana; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2004, 2:43 PM CDT for Beauregard Parish, Calcasieu Parish, Louisiana; 15 counties in Texas. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued
Apr 6, 2004, 2:43 PM CDT (19:43 UTC)
Expired
Apr 6, 2004, 3:45 PM CDT
In force
62 min
Issued by
the Storm Prediction Center

Counties Beauregard Parish, LA, Calcasieu Parish, LA, Aransas County, TX, Bee County, TX, Calhoun County, TX, DeWitt County, TX, Galveston County, TX, Goliad County, TX, Jackson County, TX, Jefferson County, TX, Jim Wells County, TX, Matagorda County, TX, Nueces County, TX, Orange County, TX, Refugio County, TX, San Patricio County, TX, Victoria County, TX

The radar

The Houston radar (KHGX), 77 km from the middle of the area, began a volume at 19:47 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

Corpus Christi, TX (KCRP), launched 12:00Z, 7.7 hours before the alert went out and 222 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, Corpus Christi, TX at 12:00Z on 2004-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1044 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, Corpus Christi, TX at 12:00Z on 2004-04-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 133 square meters per square second.193958Sfc1 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
1044 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
598 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
133 m²/s²
0-3 km storm-relative helicity
224 m²/s²
Significant tornado parameter
1.1
Supercell composite
9.2

Open this sounding in Storm Lab

The text

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

375 
ACUS11 KWNS 061943
SWOMCD
SPC MCD 061943 
LAZ000-TXZ000-062045-

MESOSCALE DISCUSSION 0280
NWS STORM PREDICTION CENTER NORMAN OK
0243 PM CDT TUE APR 06 2004

AREAS AFFECTED...MIDDLE/UPPER TX COAST INTO EXTREME SWRN LA

CONCERNING...TORNADO WATCH 47...

VALID 061943Z - 062045Z

TORNADO WATCH 47 WILL BE ALLOWED TO EXPIRE AT 21 UTC AND WILL NOT BE
ISSUED DOWNSTREAM.

NRN PART OF A LINE OF TSTMS CONTINUES TO MOVE ESEWD TOWARD THE
SABINE RVR WITH EMBEDDED SUPERCELL APPROACHING JEFFERSON COUNTY. 
THE TSTMS WILL BE ENTERING AN INCREASINGLY STABLE AIR MASS
DOWNSTREAM WHERE ELY LOW LEVEL TRAJECTORIES EXIST OVER SRN LA. AS A
RESULT...EXPECTATION IS THAT THE STORM SHOULD WEAKEN OVER THE NEXT
HOUR AS IT ENTERS COASTAL CAMERON PARISH.  

OTHERWISE...OUTFLOW BOUNDARY HAS MOVED OFFSHORE OF SERN TX WITH
NUMEROUS TSTMS/SUPERCELLS WELL OFFSHORE.  THERE HAVE BEEN A FEW
ATTEMPTS OF TSTM INITIATION OVER THE TOP OF THE COLD DOME THAT
EXISTS ACROSS MOST OF SERN TX...BUT GIVEN THAT THE MIDLEVEL IMPULSE
HAS PASSED OFF TO THE NE OF THE REGION...TSTMS HAVE REMAINED BELOW
SEVERE LIMITS.

..RACY.. 04/06/2004

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

ATTN...WFO...LCH...HGX...CRP...EWX...

28599812 29169725 29109630 28799535 29779443 30719389
30879327 28999326 27439810

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 6, 11:05 AM CDTTornado WatchSPCBeauregard, Calcasieu5 hr
Apr 6, 12:52 PM CDTMesoscale DiscussionSPCBeauregard, Calcasieu83 min
Apr 5, 10:35 PM CDTSevere Thunderstorm WatchSPCBandera, Bexar, Blanco, Comal, Frio, Gillespie and 13 more6 hr
Apr 5, 11:55 PM CDTMesoscale DiscussionSPCBandera, Blanco, Gillespie, Kendall, Kerr, Llano and 5 more2 hr
Apr 6, 2:42 AM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Burnet, Comal, Dimmit and 12 more63 min
Apr 6, 7:39 AM CDTMesoscale DiscussionSPCAtascosa, Austin, Bee, Brazoria, Colorado, DeWitt and 14 more66 min
Apr 6, 7:55 AM CDTTornado WatchSPCAransas, Austin, Bee, Brazoria, Brazos, Burleson and 20 more5 hr
Apr 6, 9:29 AM CDTMesoscale DiscussionSPCAransas, Austin, Bee, Brazoria, Brazos, Burleson and 20 more91 min
Apr 6, 10:27 AM CDTMesoscale DiscussionSPCAustin, Brazoria, Chambers, Colorado, Fort Bend, Galveston and 3 more63 min
Apr 6, 2:19 PM CDTMesoscale DiscussionSPCArcher, Baylor, Childress, Clay, Cottle, Crosby and 22 more116 min

Nearby

Mesoscale Discussions in Texas, 2004Mesoscale Discussions in Louisiana, 2004Every mesoscale discussion in 2004

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.