Alert archive / Texas / Mesoscale Discussions in 2004

Mesoscale Discussion 261

April 4, 200415 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2004, 11:38 AM CDT for 15 counties in Texas. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Apr 4, 2004, 11:38 AM CDT (16:38 UTC)
Expired: Apr 4, 2004, 2:15 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center

Counties Brooks County, TX, Cameron County, TX, Dimmit County, TX, Duval County, TX, Hidalgo County, TX, Jim Hogg County, TX, Jim Wells County, TX, Kenedy County, TX, La Salle County, TX, Live Oak County, TX, McMullen County, TX, Starr County, TX, Webb County, TX, Willacy County, TX, Zapata County, TX

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 41Apr 4, 1:10 PM CDT

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 4.6 hours before the alert went out and 151 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1090 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 628 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 36 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.3

Open this sounding in Storm Lab

The text

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

549 
ACUS11 KWNS 041639
SWOMCD
SPC MCD 041638 
TXZ000-041915-

MESOSCALE DISCUSSION 0261
NWS STORM PREDICTION CENTER NORMAN OK
1138 AM CDT SUN APR 04 2004

AREAS AFFECTED...S TX

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 041638Z - 041915Z

WIDELY SCATTERED TO SCATTERED STORMS EXPECTED TO INCREASE OVER S TX
INTO THE AFTERNOON. LARGE HAIL AND ISOLATED DAMAGING WIND GUSTS WILL
BE THE MAIN THREATS.

SATELLITE DATA INDICATES SEVERAL NW-SE ORIENTED BOUNDARIES ACROSS
SRN TX AND AN OUTFLOW BOUNDARY WITH PRE-EXISTING STORMS S OF DEL
RIO. RICH LOW LEVEL MOISTURE WITH DEWPOINTS AROUND 70...POCKETS OF
SURFACE HEATING AND STEEP LAPSE RATES ARE PROMOTING DESTABILIZATION
IN THIS AREA WITH MLCAPE FROM 2000 TO 2500 J/KG EXPECTED. S TX IS
CURRENTLY UNDER UPPER LEVEL SHORTWAVE RIDGING WITH RELATIVELY WEAK
MID LEVEL FLOW. HOWEVER...SOME HEIGHT FALLS ARE EXPECTED AS THIS
RIDGE AXIS SHIFTS TO THE EAST. RUC AND SATELLITE DATA BOTH SUGGEST
PRESENCE OF AN UPSTREAM SHORTWAVE TROUGH THAT MAY AFFECT S TX THIS
AFTERNOON. HEIGHT FALLS...THOUGH SMALL...SHOULD RESULT IN SOME
INCREASE IN MID LEVEL FLOW WITH RESULTING INCREASE IN DEEP LAYER
SHEAR. THE BROWNSVILLE VWP DATA ALREADY SHOWS SIGNIFICANT VEERING
FROM ELY LOW LEVEL FLOW TO SWLY ABOVE 3 KM. WITH WEAK CAP IN
PLACE...STORMS ARE EXPECTED TO DEVELOP AND INTENSIFY ALONG
PRE-EXISTING BOUNDARIES AS THE ATMOSPHERE CONTINUES TO DESTABILIZE.
BOTH MULTICELL AND SUPERCELL STORM STRUCTURES ARE EXPECTED WITH
ISOLATED LARGE HAIL AND DAMAGING WIND THE MAIN THREATS.

..DIAL.. 04/04/2004

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

ATTN...WFO...CRP...EWX...BRO...

27779975 28590002 28669818 27319763 25989742 26409870
26829915

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 4, 4:40 AM CDT	Mesoscale Discussion	SPC	Crane, Crockett, Culberson, Ector, Jeff Davis, Kinney and 8 more	3 hr
Apr 4, 12:41 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bexar, Caldwell, DeWitt, Dimmit, Frio and 7 more	3 hr
Apr 4, 1:10 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Dimmit, Duval, Frio, Jim Wells, Karnes and 8 more	6 hr
Apr 4, 1:23 PM CDT	Mesoscale Discussion	SPC	Brewster, Terrell, Val Verde	2 hr
Apr 4, 2:10 PM CDT	Severe Thunderstorm Watch	SPC	Brewster, Presidio, Terrell	6 hr
Apr 4, 3:30 PM CDT	Mesoscale Discussion	SPC	Atascosa, Duval, Jim Wells, Karnes, La Salle, Live Oak and 3 more	2 hr
Apr 4, 5:32 PM CDT	Mesoscale Discussion	SPC	Atascosa, Austin, Bastrop, Bee, Bexar, Burleson and 19 more	118 min
Apr 4, 6:40 PM CDT	Severe Thunderstorm Watch	SPC	Aransas, Atascosa, Bee, Brooks, Duval, Goliad and 15 more	4 hr

Nearby

Mesoscale Discussions in Texas, 2004 Every 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.