Alert archive / Texas / Mesoscale Discussions in 2003
Mesoscale Discussion 439
The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2003, 3:36 PM CDT for 6 counties in Texas. It was in force for 114 min.
The area
The outline as issued.
The facts
- Issued
- Apr 7, 2003, 3:36 PM CDT (20:36 UTC)
- Expired
- Apr 7, 2003, 5:30 PM CDT
- In force
- 114 min
- Issued by
- the Storm Prediction Center
Counties Edwards County, TX, Kinney County, TX, Maverick County, TX, Real County, TX, Uvalde County, TX, Val Verde County, TX
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Del Rio, TX (KDRT), launched 12:00Z, 8.6 hours before the alert went out and 37 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
- 973 J/kg
- Mixed-layer CIN
- -60 J/kg
- Mixed-layer LCL
- 1167 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 86 m²/s²
- 0-3 km storm-relative helicity
- 183 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.0
The text
As transmitted, in the capitals the NWS used until 2016.
130 ACUS11 KWNS 072037 SWOMCD SPC MCD 072036 TXZ000-072230- MESOSCALE DISCUSSION 0439 NWS STORM PREDICTION CENTER NORMAN OK 0336 PM CDT MON APR 07 2003 AREAS AFFECTED...PORTIONS SW/S-CENTRAL TX CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 072036Z - 072230Z TSTMS MAY DEVELOP ALONG COMBINED FRONTAL/OUTFLOW BOUNDARIES ANALYZED FROM TERR ELL COUNTY EWD TO PORTIONS GILLESPIE COUNTY. LARGE HAIL IS LIKELY FROM ANY TSTMS THAT DEVELOP...WITH DAMAGING WIND ALSO POSSIBLE. WW MAY BE REQUIRED. BOUNDARY ACROSS PORTIONS TERRELL/VAL VERDE/EDWARDS COUNTIES HAS BEEN REINFORCED BY OUTFLOW FROM EARLIER TSTMS SW SJT AND REMAINS PROGRESSIVE BUT IS DECELERATING IN ITS SWD MOTION. EXPECT BOUNDARY TO STALL IN THIS AREA AND DRIFT NWD ELSEWHERE FOR ANOTHER 2-3 HOURS BEFORE POST-FRONTAL ISALLOBARIC FORCING CAUSES RENEWED SWD MOTION. MEANWHILE...TCU NOW EVIDENT IN VIS IMAGERY ALONG/S OF BOUNDARY WOULD NOT BE UNDERCUT SUBSTANTIALLY BY COLD BOUNDARY LAYER DENSITY CURRENT...AND MAY DEVELOP INTO CB. MODIFIED DRT RAOB AND RUC FORECAST SOUNDINGS SUGGEST VERY LITTLE CINH REMAINING WITH 8-9 DEG C MIDLEVEL LAPSE RATES CONTRIBUTING TO ROUGHLY 2000 J/KG MLCAPE. MOISTURE ADVECTION AND TRANSPORT WILL CONTINUE ON WARM SECTOR SSEWD TOWARD RIO GRANDE ALLEY...HELPING TO MAINTAIN CAPE EVEN AFTER PEAK OF DIABATIC SFC HEATING PASSES. REGIONAL VWP DATA SHOWS 5-15 KT SELY FLOW AROUND 850 MB -- WHICH BECOMES 15-20 KT SR INFLOW WITH REASONABLE EWD STORM MOTIONS ALONG BOUNDARY. ADDITIONAL CONVECTION MAY DEVELOP IN ZONE OF OROGRAPHIC FORCING OVER MEX MOUNTAINS W DRT...MOVING EWD TOWARD TX BORDER. OBSERVED 20-25 DEG F SURFACE DEW POINT DEPRESSIONS AND ACCORDINGLY MIXED BOUNDARY LAYER PROFILES IN FORECAST SOUNDINGS YIELD INVERTED-V THERMODYNAMIC PROFILE SUITABLE FOR EVAPORATIVELY MAINTAINING/STRENGTHENING CONVECTIVE DOWNDRAFTS BETWEEN CLOUD BASE AND SFC. ..EDWARDS.. 04/07/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...EWX...MAF... 29800193 30150200 30250002 29819931 29429930 28510035
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 7, 9:42 AM CDT | Mesoscale Discussion | SPC | Chambers, Galveston, Jefferson, Orange | 3 hr |
| Apr 7, 10:05 AM CDT | Severe Thunderstorm Watch | SPC | Chambers, Galveston, Hardin, Jefferson, Liberty, Orange | 6 hr |
| Apr 7, 12:24 PM CDT | Mesoscale Discussion | SPC | Atascosa, Austin, Bastrop, Bee, Bexar, Brazoria and 28 more | 66 min |
| Apr 7, 1:00 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Austin, Bee, Bexar, Brazoria, Caldwell and 23 more | 5 hr |
| Apr 7, 2:13 PM CDT | Mesoscale Discussion | SPC | Chambers, Hardin, Jefferson, Orange | 3 hr |
| Apr 7, 2:36 PM CDT | Mesoscale Discussion | SPC | Chambers, Hardin, Jefferson, Orange | 114 min |
| Apr 7, 3:40 PM CDT | Severe Thunderstorm Watch | SPC | Chambers, Galveston, Jefferson, Liberty, Orange | 5 hr |
| Apr 7, 4:35 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bandera, Bee, Bexar, Blanco, Caldwell and 22 more | 5 hr |
| Apr 7, 5:58 PM CDT | Mesoscale Discussion | SPC | Chambers, Galveston, Jefferson | 2 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.