Alert archive / Texas / Mesoscale Discussions in 2003
Mesoscale Discussion 98
The Storm Prediction Center issued this mesoscale discussion at Feb 20, 2003, 11:58 AM CST for 12 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 20, 2003, 11:58 AM CST (17:58 UTC)
- Expired
- Feb 20, 2003, 2:00 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
Counties Aransas County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Jackson County, TX, Matagorda County, TX, Refugio County, TX, San Patricio County, TX, Victoria County, TX, Wharton County, TX
The radar
The Houston radar (KHGX), 110 km from the middle of the area, began a volume at 18:00 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
Corpus Christi, TX (KCRP), launched 12:00Z, 6.0 hours before the alert went out and 189 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
- 353 J/kg
- Mixed-layer CIN
- -36 J/kg
- Mixed-layer LCL
- 638 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 123 m²/s²
- 0-3 km storm-relative helicity
- 98 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 2.1
The text
As transmitted, in the capitals the NWS used until 2016.
648 ACUS11 KWNS 201759 SWOMCD SPC MCD 201758 TXZ000-202000- MESOSCALE DISCUSSION 0098 NWS STORM PREDICTION CENTER NORMAN OK 1158 AM CST THU FEB 20 2003 AREAS AFFECTED...SE TX CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 201758Z - 202000Z AREA IS BEING MONITORED FOR INCREASING SEVERE THREAT THIS AFTERNOON. PERSISTENT WEAK SURFACE LOW IS LOCATED WEST SOUTHWEST OF CORPUS CHRISTI...WITH A WEAK BAROCLINIC ZONE EXTENDING NORTHEASTWARD INTO THE FORT POLK LA AREA. DEEPER MOIST BOUNDARY LAYER SOUTHEAST OF FRONTAL ZONE IS CURRENTLY CONFINED TO AREAS ALONG/SOUTH OF A COASTAL FRONT EXTENDING ACROSS THE CORPUS CHRISTI AREA INTO THE WESTERN GULF OF MEXICO. HOWEVER...MODELS SUGGEST ZONE OF ENHANCED WARM ADVECTION ASSOCIATED WITH A 30 TO 40 KT LOW-LEVEL JET WILL SPREAD FROM THE LOWER TO THE UPPER TEXAS COAST THIS AFTERNOON. THIS...IN CONJUNCTION WITH DAYTIME HEATING WILL WEAKEN SHALLOW SURFACE-BASED INVERSION LAYER NORTH OF COASTAL FRONT...FROM VICTORIA INTO THE VICINITY OF HOUSTON. INCREASING LARGE-SCALE UPWARD VERTICAL MOTION AND DESTABILIZATION IS EXPECTED TO SUPPORT NEW SURFACE-BASED CONVECTIVE DEVELOPMENT NEAR/NORTH OF VICTORIA BY 21Z...WHILE ONGOING ACTIVITY WEST OF HOUSTON BECOMES INCREASING SURFACE-BASED AS IT SPREADS NORTHEASTWARD. VERTICAL SHEAR PROFILES ARE NOT PARTICULARLY STRONG...BUT APPEAR SUFFICIENT FOR SUPERCELLS. DUE TO THERMODYNAMIC ENVIRONMENT WITH WEAK LOW/MID-LEVEL LAPSE RATES AND LIMITED CAPE...THREAT FOR HAIL EXCEEDING SEVERE LIMITS APPEARS MARGINAL...BUT POTENTIAL FOR ISOLATED TORNADOES DOES EXIST. ..KERR.. 02/20/2003 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... 27849712 28099770 29169664 29449617 29739576 29929502 29789467 29429456
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 20, 6:42 AM CST | Mesoscale Discussion | SPC | Aransas, Atascosa, Austin, Bastrop, Bee, Bexar and 30 more | 3 hr |
| Feb 20, 5:19 PM CST | Mesoscale Discussion | SPC | Brewster, Culberson, El Paso, Hudspeth, Jeff Davis, Presidio | 3 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.