Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 301
The Storm Prediction Center issued this mesoscale discussion at Mar 19, 2012, 11:53 PM CDT for 34 counties in Texas. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- Mar 19, 2012, 11:53 PM CDT (04:53 UTC)
- Expired
- Mar 20, 2012, 1:00 AM CDT
- In force
- 67 min
- Issued by
- the Storm Prediction Center
All 34 counties
Atascosa County, TX, Bastrop County, TX, Bell County, TX, Bexar County, TX, Burleson County, TX, Caldwell County, TX, Comal County, TX, Dimmit County, TX, Falls County, TX, Freestone County, TX, Frio County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Henderson County, TX, Karnes County, TX, Kaufman County, TX, Kendall County, TX, La Salle County, TX, Lee County, TX, Limestone County, TX, McMullen County, TX, Medina County, TX, Milam County, TX, Navarro County, TX, Rains County, TX, Robertson County, TX, Travis County, TX, Van Zandt County, TX, Webb County, TX, Williamson County, TX, Wilson County, TX, Wood County, TX, Zavala County, TX
The radar
The Austin/San Antonio radar (KEWX), 39 km from the middle of the area, began a volume at 04:55 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 00:00Z, 4.9 hours before the alert went out and 268 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
- 2851 J/kg
- Mixed-layer CIN
- -113 J/kg
- Mixed-layer LCL
- 778 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 121 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.0
The text
As transmitted, in the capitals the NWS used until 2016.
259
ACUS11 KWNS 200454
SWOMCD
SPC MCD 200453
TXZ000-200600-
MESOSCALE DISCUSSION 0301
NWS STORM PREDICTION CENTER NORMAN OK
1153 PM CDT MON MAR 19 2012
AREAS AFFECTED...SRN THROUGH NERN TX
CONCERNING...TORNADO WATCH 87...89...
VALID 200453Z - 200600Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 87...89...CONTINUES.
SEVERE THREAT WILL LIKELY CONTINUE THROUGH THE EARLY MORNING ACROSS
THE REMAINING PARTS OF WW 87 AND 89 FROM SRN THROUGH NERN TX. THE
PRIMARY THREATS WILL BE DAMAGING WIND...LARGE HAIL AND VERY HEAVY
RAIN...THOUGH ISOLATED TORNADOES CANNOT BE RULED OUT. BOTH WW 87 AND
89 WILL LIKELY NEED TO BE REPLACED BEFORE THEIR EXPIRATION TIME OF
06Z AND 07Z RESPECTIVELY...POSSIBLY WITH ONE WW.
STORMS WILL CONTINUE DEVELOPING INTO THE EARLY MORNING ALONG THE
EXTENSIVE AND SLOW MOVING OUTFLOW BOUNDARY FROM SRN THROUGH NERN TX
PROMOTED BY MOIST INFLOW FROM THE MODERATELY UNSTABLE WARM SECTOR
AND FORCING FOR DEEP ASCENT ACCOMPANYING AN IMPULSE MOVING THROUGH
BASE OF UPPER TROUGH. THE SHEAR/INSTABILITY PARAMETER SPACE WILL
CONTINUE TO SUPPORT EMBEDDED ORGANIZED STORMS...BUT A STABILIZING
BOUNDARY LAYER AND PREDOMINANT LINEAR MODE SUGGEST THE PRIMARY
SEVERE THREATS WILL BE LARGE HAIL AND DAMAGING WIND. HOWEVER...LARGE
HODOGRAPHS WILL PERSIST ALONG LLJ EAST OF THE LINE...AND ISOLATED
TORNADOES REMAIN POSSIBLE WITH MORE ORGANIZED EMBEDDED SUPERCELL
STRUCTURES.
..DIAL.. 03/20/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...SHV...HGX...FWD...CRP...EWX...
LAT...LON 28470023 29349948 30559802 31099756 32999600 32869503
29059753 27489935 28470023SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 19, 7:28 PM CDT | Tornado Watch | SPC | Anderson, Bell, Bowie, Camp, Cass, Cherokee and 30 more | 9 hr |
| Mar 19, 8:22 PM CDT | Mesoscale Discussion | SPC | Bandera, Bell, Bexar, Blanco, Burnet, Comal and 30 more | 53 min |
| Mar 19, 9:46 PM CDT | Mesoscale Discussion | SPC | Bandera, Bell, Blanco, Burnet, Coryell, Ellis and 18 more | 119 min |
| Mar 20, 12:48 AM CDT | Severe Thunderstorm Watch | SPC | Aransas, Atascosa, Austin, Bastrop, Bee, Bexar and 52 more | 9 hr |
| Mar 20, 2:43 AM CDT | Mesoscale Discussion | SPC | Aransas, Bee, Calhoun, Colorado, DeWitt, Duval and 13 more | 92 min |
| Mar 20, 5:26 AM CDT | Mesoscale Discussion | SPC | Brazoria, Calhoun, Fort Bend, Harris, Liberty, Matagorda and 3 more | 2 hr |
| Mar 20, 9:03 AM CDT | Mesoscale Discussion | SPC | Chambers, Galveston, Hardin, Jasper, Jefferson, Liberty and 6 more | 87 min |
| Mar 20, 9:46 AM CDT | Tornado Watch | SPC | Hardin, Jasper, Jefferson, Newton, Orange, Sabine and 3 more | 7 hr |
Nearby
Mesoscale Discussions in Texas, 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.