Alert archive / Texas / Mesoscale Discussions in 2003
Mesoscale Discussion 271
The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2003, 2:03 AM CST for 29 counties in Texas. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 18, 2003, 2:03 AM CST (08:03 UTC)
- Expired
- Mar 18, 2003, 5:00 AM CST
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
All 29 counties
Bell County, TX, Bosque County, TX, Burnet County, TX, Collin County, TX, Coryell County, TX, Dallas County, TX, Denton County, TX, Ellis County, TX, Erath County, TX, Falls County, TX, Freestone County, TX, Hamilton County, TX, Hill County, TX, Hood County, TX, Johnson County, TX, Kaufman County, TX, Lampasas County, TX, Limestone County, TX, Llano County, TX, McLennan County, TX, Mills County, TX, Navarro County, TX, Parker County, TX, Rockwall County, TX, San Saba County, TX, Somervell County, TX, Tarrant County, TX, Van Zandt County, TX, Williamson County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 103 km from the middle of the area, began a volume at 08:05 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, 8.1 hours before the alert went out and 132 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
- 401 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 1196 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 40 m²/s²
- 0-3 km storm-relative helicity
- 133 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.8
The text
As transmitted, in the capitals the NWS used until 2016.
186 ACUS11 KWNS 180803 SWOMCD SPC MCD 180803 TXZ000-181100- MESOSCALE DISCUSSION 0271 NWS STORM PREDICTION CENTER NORMAN OK 0203 AM CST TUE MAR 18 2003 AREAS AFFECTED...CNTRL THROUGH N CNTRL TX CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 180803Z - 181100Z THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY FROM CNTRL THROUGH N CNTRL TX INTO THE MORNING. HAIL AND ISOLATED DAMAGING WIND GUSTS WILL BE POSSIBLE. AREA IS BEING MONITORED FOR WW. LATEST SURFACE DATA SHOW A COLD FRONT FROM E OF MINERAL WELLS IN N CNTRL TX SWWD TO JUST W OF FREDERICKSBURG TO E OF DEL RIO MOVING EWD. WV IMAGERY CONTINUES TO SHOW INCREASING CLOUDS ASSOCIATED WITH LARGE SCALE ASCENT/STRONG UPPER DIVERGENCE IN EXIT REGION OF THE UPPER JET THAT IS APPROACHING S CNTRL TX. A NARROW AXIS OF MARGINAL INSTABILITY HAS DEVELOPED FROM CNTRL THROUGH N CNTRL TX WHERE THERMAL TROUGH IN EXIT REGION HAS OVERTAKEN MOIST AXIS. THE ZONE OF STRONGER ASCENT WILL CONTINUE TO SPREAD NEWD...EVENTUALLY OVERTAKING THE FRONT. AS THIS OCCURS...STORMS ARE EXPECTED TO INCREASE ALONG OR JUST BEHIND SURFACE FRONT...POSSIBLY EVOLVING INTO LINES OR LINE SEGMENTS. HOWEVER...DEEP LAYER SHEAR SUGGESTS EMBEDDED SUPERCELLS ARE ALSO POSSIBLE. PRIMARY LIMITING FACTOR CONTINUES TO BE MARGINAL INSTABILITY. ..DIAL.. 03/18/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...FWD...EWX...SJT... 30559920 32689801 33459681 32829573 31359622 30309784
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 17, 8:19 PM CST | Mesoscale Discussion | SPC | Archer, Bosque, Clay, Cooke, Denton, Eastland and 13 more | 86 min |
| Mar 17, 10:27 PM CST | Mesoscale Discussion | SPC | Archer, Brown, Callahan, Coleman, Comanche, Concho and 20 more | 3 hr |
| Mar 18, 9:36 AM CST | Mesoscale Discussion | SPC | Angelina, Bowie, Camp, Cass, Cherokee, Franklin and 22 more | 3 hr |
| Mar 18, 11:40 AM CST | Tornado Watch | SPC | Angelina, Brazoria, Chambers, Galveston, Hardin, Harris and 13 more | 5 hr |
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.