Alert archive / Texas / Mesoscale Discussions in 2003
Mesoscale Discussion 556
The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2003, 9:11 AM CDT for 6 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 24, 2003, 9:11 AM CDT (14:11 UTC)
- Expired
- Apr 24, 2003, 11:15 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Fort Bend County, TX, Harris County, TX, Liberty County, TX, Montgomery County, TX, Polk County, TX, San Jacinto County, TX
The radar
The Houston radar (KHGX), 79 km from the middle of the area, began a volume at 14:11 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 nearest sounding before it
Lake Charles Mun, LA (KLCH), launched 12:00Z, 2.2 hours before the alert went out and 217 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.
- Mixed-layer CAPE
- 653 J/kg
- Mixed-layer CIN
- -125 J/kg
- Mixed-layer LCL
- 998 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 249 m²/s²
- 0-3 km storm-relative helicity
- 298 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 9.9
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 241411 SWOMCD SPC MCD 241411 TXZ000-241615- MESOSCALE DISCUSSION 0556 NWS STORM PREDICTION CENTER NORMAN OK 0911 AM CDT THU APR 24 2003 AREAS AFFECTED...SE TX CONCERNING...TORNADO WATCH 155... VALID 241411Z - 241615Z DIFLUENT/DIVERGENT UPPER FLOW FIELD IN ZONE BETWEEN POLAR AND SUBTROPICAL JET STREAKS APPEARED TO BE PRIMARY FORCING FOR LARGE SUPERCELL WEST NORTHWEST OF HOUSTON. AS POLAR JET STREAK LIFTS INTO THE ARKLATEX NEXT FEW HOURS...AND SUBTROPICAL JET STREAK CONTINUES EAST SOUTHEASTWARD TOWARD THE WESTERN GULF OF MEXICO... LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION OVER SOUTHEAST TEXAS WILL DIMINISH. WEAK SURFACE RIDGING ACROSS SOUTHEAST TEXAS IS NOT PARTICULARLY FAVORABLE FOR ADDITIONAL INTENSE CONVECTIVE DEVELOPMENT...AND FORECAST SOUNDINGS SUGGEST CONTINUING PRESENCE OF SUBSTANTIAL LOW/MID LEVEL CAPPING. HOWEVER...RIGHT AND LEFT MOVING STORMS ASSOCIATED WITH SUPERCELL WHICH HAS RECENTLY SPLIT MAY BE SLOW TO WEAKEN THIS MORNING. RIGHT MOVER WILL CONTINUE TO POSE RISK FOR AT LEAST LARGE HAIL ACROSS THE HOUSTON AREA IN THE 16-17Z TIME FRAME. ..KERR.. 04/24/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...HGX... 30249582 30589559 30939514 30819473 30269481 29819480 29539525 29439585 29539605 29739616
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 23, 7:00 PM CDT | Mesoscale Discussion | SPC | Crockett, Edwards, Kimble, Kinney, Mason, Menard and 5 more | 90 min |
| Apr 23, 7:03 PM CDT | Mesoscale Discussion | SPC | Bosque, Collin, Comanche, Cooke, Coryell, Dallas and 25 more | 117 min |
| Apr 23, 7:45 PM CDT | Tornado Watch | SPC | Bandera, Bexar, Blanco, Burnet, Caldwell, Comal and 11 more | 4 hr |
| Apr 23, 8:43 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Brown, Callahan, Clay, Coleman and 15 more | 77 min |
| Apr 23, 9:35 PM CDT | Severe Thunderstorm Watch | SPC | Collin, Cooke, Dallas, Delta, Denton, Ellis and 20 more | 5 hr |
| Apr 23, 11:43 PM CDT | Mesoscale Discussion | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Delta and 23 more | 2 hr |
| Apr 24, 2:41 AM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Cass, Cherokee, Falls, Freestone and 12 more | 2 hr |
| Apr 24, 6:30 AM CDT | Severe Thunderstorm Watch | SPC | Angelina, Hardin, Jasper, Newton, Sabine, San Augustine and 2 more | 5 hr |
| Apr 24, 6:40 AM CDT | Severe Thunderstorm Watch | SPC | Angelina, Hardin, Jasper, Newton, Sabine, San Augustine and 2 more | 4 hr |
| Apr 24, 7:14 AM CDT | Mesoscale Discussion | SPC | Austin, Bastrop, Brazoria, Brazos, Burleson, Caldwell and 22 more | 2 hr |
| Apr 24, 7:30 AM CDT | Tornado Watch | SPC | Angelina, Austin, Brazoria, Brazos, Burleson, Chambers and 17 more | 6 hr |
| Apr 24, 11:40 AM CDT | Mesoscale Discussion | SPC | Sabine, San Augustine, Shelby | 65 min |
Nearby
Mesoscale Discussions in Texas, 2003Every mesoscale discussion in 2003
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.