Alert archive / Texas / Mesoscale Discussions in 2004
Mesoscale Discussion 2421
The Storm Prediction Center issued this mesoscale discussion at Nov 22, 2004, 10:49 AM CST for Beauregard Parish, Calcasieu Parish, Louisiana; 27 counties in Texas. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- Nov 22, 2004, 10:49 AM CST (16:49 UTC)
- Expired
- Nov 22, 2004, 12:45 PM CST
- In force
- 116 min
- Issued by
- the Storm Prediction Center
All 29 counties
Beauregard Parish, LA, Calcasieu Parish, LA, Atascosa County, TX, Austin County, TX, Bexar County, TX, Brazoria County, TX, Chambers County, TX, Colorado County, TX, DeWitt County, TX, Fayette County, TX, Fort Bend County, TX, Galveston County, TX, Goliad County, TX, Gonzales County, TX, Guadalupe County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jefferson County, TX, Karnes County, TX, Lavaca County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Orange County, TX, Victoria County, TX, Waller County, TX, Wharton County, TX, Wilson County, TX
The radar
The Houston radar (KHGX), 89 km from the middle of the area, began a volume at 16:53 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.
The nearest sounding before it
Corpus Christi, TX (KCRP), launched 12:00Z, 4.8 hours before the alert went out and 234 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
- 1000 J/kg
- Mixed-layer CIN
- -12 J/kg
- Mixed-layer LCL
- 687 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 72 m²/s²
- 0-3 km storm-relative helicity
- 107 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 2.8
The text
As transmitted, in the capitals the NWS used until 2016.
560 ACUS11 KWNS 221649 SWOMCD SPC MCD 221649 LAZ000-TXZ000-221845- MESOSCALE DISCUSSION 2421 NWS STORM PREDICTION CENTER NORMAN OK 1049 AM CST MON NOV 22 2004 AREAS AFFECTED...TX HILL COUNTRY ACROSS THE UPPER TX COAST/FAR SWRN LA CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 221649Z - 221845Z 16Z SURFACE MESOSCALE ANALYSIS INDICATES WARM/COASTAL FRONT BECOMING WELL DEFINED FROM CENTRAL LA SWWD INTO NRN PART OF HOU AREA AND THEN WWD ROUGHLY ALONG I-10 TO NEAR SAT. LOW CENTER NEAR COT WILL LIKELY REMAIN IN PLACE ALONG TRIPLE POINT OF WARM FRONT AND N-S ORIENTED STALLED FRONT EXTENDING INTO NERN TX/WRN AR. WARM SECTOR REMAINS VERY MOIST AND WILL UNDERGO FURTHER HEATING WITH BREAKS IN CLOUDS EVIDENT ON VIS IMAGERY. SUPERCELL HAS BEEN PERSISTENT OVER NRN PORTIONS OF HOU DURING THE PAST HOUR...WITH 0-1 KM SHEAR AROUND 25 KT EVIDENT ON VWP FROM KHGX. GIVEN PROXIMITY OF BOUNDARY AND DESTABILIZING WARM SECTOR...TORNADO THREAT WILL CONTINUE WITH THIS CELL. WEAKENING CIN AND INCREASING MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE SUGGEST FURTHER SEVERE THUNDERSTORMS MAY DEVELOP WITHIN WW DURING THE NEXT FEW HOURS. SHEAR IS ALSO SUPPORTIVE OF SUPERCELLS...WITH TORNADO THREAT INCREASED NEAR THE FRONT. SHOULD A STORM DEVELOP WITHIN WARM SECTOR NEAR VCT...STRONGER SLY LOW LEVEL WINDS WILL BE SUPPORTIVE OF TORNADOES AS WELL. ..EVANS.. 11/22/2004 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LCH...HGX...CRP...EWX... 28879530 28389800 28669910 29379892 29919717 30789386 30679296 29779336
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 22, 6:18 AM CST | Mesoscale Discussion | SPC | Austin, Bastrop, Bexar, Caldwell, Chambers, Colorado and 19 more | 87 min |
| Nov 22, 9:10 AM CST | Tornado Watch | SPC | Austin, Bexar, Caldwell, Chambers, Colorado, DeWitt and 17 more | 5 hr |
| Nov 22, 12:56 PM CST | Mesoscale Discussion | SPC | Atascosa, Austin, Bexar, Brazoria, Chambers, Colorado and 20 more | 64 min |
| Nov 22, 1:35 PM CST | Tornado Watch | SPC | Austin, Bexar, Caldwell, Chambers, Colorado, DeWitt and 16 more | 5 hr |
| Nov 22, 3:31 PM CST | Mesoscale Discussion | SPC | El Paso, Hudspeth | 2 hr |
| Nov 22, 3:34 PM CST | Mesoscale Discussion | SPC | Austin, Bee, Brazoria, Calhoun, Chambers, Colorado and 18 more | 116 min |
Nearby
Mesoscale Discussions in Texas, 2004Mesoscale Discussions in Louisiana, 2004Every 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.