Alert archive / Texas / Mesoscale Discussions in 2004

Mesoscale Discussion 270

April 5, 20048 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2004, 1:09 PM CDT for 8 counties in Texas. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Apr 5, 2004, 1:09 PM CDT (18:09 UTC)
Expired: Apr 5, 2004, 2:45 PM CDT
In force: 96 min
Issued by: the Storm Prediction Center

Counties Brewster County, TX, Culberson County, TX, Hudspeth County, TX, Jeff Davis County, TX, Pecos County, TX, Presidio County, TX, Reeves County, TX, Ward County, TX

The radar

The El Paso radar (KEPZ), 230 km from the middle of the area, began a volume at 18:11 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.

Severe Thunderstorm Watch 44Apr 5, 2:00 PM CDT

The nearest sounding before it

Santa Teresa, NM (KEPZ), launched 12:00Z, 6.2 hours before the alert went out and 230 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: 2 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 814 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 49 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.

323 
ACUS11 KWNS 051810
SWOMCD
SPC MCD 051809 
TXZ000-051945-

MESOSCALE DISCUSSION 0270
NWS STORM PREDICTION CENTER NORMAN OK
0109 PM CDT MON APR 05 2004

AREAS AFFECTED...SW TX

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 051809Z - 051945Z

TSTMS WILL INCREASE IN NUMBER AND INTENSITY THIS AFTERNOON.  A WW 
MAY BE REQUIRED.

PROSPECTS FOR TSTMS ARE INCREASING ACROSS SWRN TX...ESPECIALLY SOUTH
OF I-10 SWD INTO NERN CHIHUAHUA.  BOUNDARY LAYER AIR MASS IS
BEGINNING TO HEAT/DESTABILIZE OWING TO STRATUS ERODING NEAR/SOUTH OF
KMRF.  WATER VAPOR LOOP SHOWS THAT THE UPPER LOW IS EDGING CLOSER TO
 SWRN TX/NRN MEXICO AND MID TROPOSPHERIC LAPSE RATES WILL CONTINUE
TO STEEPEN THROUGH THE AFTERNOON.  

LATEST VSBL IMAGERY SHOWS A FEW MDT CU OVER THE MOUNTAINS SOUTH OF
ALPINE ATTM AND ADDITIONAL TSTMS ARE FORMING OVER NERN CHIHUAHUA
CLOSER TO CORE OF THE UPPER LOW.  AS LARGE SCALE SUPPORT INCREASES
AND ADDITIONAL HEATING TAKES PLACE...MORE TSTMS ARE APT TO DEVELOP
OVER THE NEXT FEW HOURS.

WHILE CONVECTIVE MODE COULD START OUT AS DISCRETE
CELLS...ORIENTATION OF THE MEAN WIND VECTORS IN THE 2-6KM LAYER
SUGGESTS THAT AN EVOLUTION INTO LINE SEGMENTS SHOULD OCCUR A FEW
HOURS AFTER INITIATION.  BUT...DEEP LAYER WIND SHEAR WILL BE
SUFFICIENT FOR ROTATING STORMS EMBEDDED WITHIN THE LINES.  

COLD MID TROPOSPHERE...INCREASING VERTICAL SHEAR AND SBCAPES OF
500-750 J/KG SUGGEST THAT LARGE HAIL WOULD BE THE PREDOMINATE SEVERE
THREAT...THOUGH DAMAGING WINDS COULD ALSO OCCUR.

..RACY.. 04/05/2004

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

ATTN...WFO...MAF...EPZ...

31690638 31680295 29120185 28500542 30120659

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 4, 8:40 PM CDT	Mesoscale Discussion	SPC	Brooks, Jim Hogg, Kleberg, Nueces, Starr, Zapata	2 hr
Apr 4, 10:21 PM CDT	Mesoscale Discussion	SPC	Aransas, Brooks, Hidalgo, Jim Hogg, Kenedy, Kleberg and 3 more	114 min
Apr 5, 2:00 PM CDT	Severe Thunderstorm Watch	SPC	Brewster, Crane, Culberson, Hudspeth, Jeff Davis, Loving and 7 more	6 hr
Apr 5, 3:51 PM CDT	Mesoscale Discussion	SPC	Brewster, Crane, Culberson, Hudspeth, Jeff Davis, Loving and 7 more	114 min
Apr 5, 6:05 PM CDT	Mesoscale Discussion	SPC	Brewster, Crockett, Edwards, Kinney, Maverick, Real and 3 more	2 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; radar from the NEXRAD Level II archive.