Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 573
The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2012, 3:44 PM CDT for 10 parishes in Louisiana; 33 counties in Texas. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Apr 20, 2012, 3:44 PM CDT (20:44 UTC)
- Expired
- Apr 20, 2012, 5:15 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
All 43 counties
Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Grant Parish, LA, Jefferson Davis Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Austin County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Chambers County, TX, Colorado County, TX, Fayette County, TX, Fort Bend County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jasper County, TX, Jefferson County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Madison County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Trinity County, TX, Tyler County, TX, Victoria County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX
The radar
The Houston radar (KHGX), 59 km from the middle of the area, began a volume at 20:47 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, 8.7 hours before the alert went out and 207 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
- 177 J/kg
- Mixed-layer CIN
- -419 J/kg
- Mixed-layer LCL
- 822 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 2 m²/s²
- 0-3 km storm-relative helicity
- 75 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
427 ACUS11 KWNS 202044 SWOMCD SPC MCD 202044 LAZ000-TXZ000-202215- MESOSCALE DISCUSSION 0573 NWS STORM PREDICTION CENTER NORMAN OK 0344 PM CDT FRI APR 20 2012 AREAS AFFECTED...SOUTHEAST TX AND SWRN LA CONCERNING...SEVERE THUNDERSTORM WATCH 184... VALID 202044Z - 202215Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 184 CONTINUES. TSTMS HAVE INCREASED SIGNIFICANTLY IN AREAL COVERAGE SINCE WATCH ISSUANCE AND NOW IMMEDIATELY PRECEDE COLD FRONT/WIND SHIFT MOVING INTO MIDDLE TX COASTAL AREAS FROM MATAGORDA BAY TO POLK AND LIBERTY COUNTIES. RECENT TRENDS...INCLUDING DEEPENING CONVECTIVE COLD POOL AND STRENGTHENING MID LEVEL FLOW TO THE WEST /50KT PER LDB PROFILER DATA/...MAY CONTRIBUTE TO AN INCREASING CHANCE FOR BOWING/ACCELERATING LINE SEGMENTS WITH DAMAGING WINDS RESULTING. IN FACT...THIS CURRENTLY APPEARS TO BE OCCURRING WITH A BOWING LINE SEGMENT IN SERN HARRIS COUNTY. IN ADDITION TO VERY HEAVY RAIN /RATES TO 2 INCHES PER HOUR...AND POOR VISIBILITY...MARGINALLY SEVERE HAIL WILL ALSO BE LIKELY WITH SOME OF THE STRONGER/MORE PERSISTENT CORES. ..CARBIN.. 04/20/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LCH...SHV...HGX...FWD...CRP...EWX... LAT...LON 28359728 30569713 32239246 30249256 28359728
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 12:35 PM CDT | Mesoscale Discussion | SPC | Beauregard, Natchitoches, Sabine, Vernon | 2 hr |
| Apr 20, 12:57 PM CDT | Severe Thunderstorm Watch | SPC | Allen, Beauregard, Calcasieu, Cameron, Grant, Jefferson Davis and 5 more | 7 hr |
| Apr 20, 6:12 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 3 more | 93 min |
| Apr 19, 9:13 PM CDT | Mesoscale Discussion | SPC | Cooke, Denton, Grayson, Jack, Montague, Wise | 62 min |
| Apr 19, 10:49 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Clay, Cooke, Foard, Hardeman and 7 more | 116 min |
| Apr 20, 1:30 PM CDT | Mesoscale Discussion | SPC | Brooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 7 more | 2 hr |
| Apr 20, 2:29 PM CDT | Severe Thunderstorm Watch | SPC | Brooks, Cameron, Duval, Hidalgo, Jim Hogg, Jim Wells and 10 more | 5 hr |
| Apr 20, 4:48 PM CDT | Mesoscale Discussion | SPC | Brooks, Cameron, Hidalgo, Kenedy, Kleberg, Nueces and 2 more | 57 min |
Nearby
Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Louisiana, 2012Every mesoscale discussion in 2012
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.