Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 445
The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2012, 12:19 PM CDT for 31 counties in Texas. It was in force for 86 min.
The area
The outline as issued.
The facts
- Issued
- Apr 4, 2012, 12:19 PM CDT (17:19 UTC)
- Expired
- Apr 4, 2012, 1:45 PM CDT
- In force
- 86 min
- Issued by
- the Storm Prediction Center
All 31 counties
Aransas County, TX, Austin County, TX, Bee County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Colorado County, TX, DeWitt County, TX, Fayette County, TX, Fort Bend County, TX, Goliad County, TX, Gonzales County, TX, Grimes County, TX, Harris County, TX, Jackson County, TX, Jim Wells County, TX, Karnes County, TX, Kleberg County, TX, Lavaca County, TX, Live Oak County, TX, Matagorda County, TX, Montgomery County, TX, Nueces County, TX, Refugio County, TX, San Patricio County, TX, Victoria County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX, Wilson County, TX
The radar
The Houston radar (KHGX), 134 km from the middle of the area, began a volume at 17:20 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, 5.3 hours before the alert went out and 184 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
- 3692 J/kg
- Mixed-layer CIN
- -3 J/kg
- Mixed-layer LCL
- 499 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- -42 m²/s²
- 0-3 km storm-relative helicity
- 18 m²/s²
- Significant tornado parameter
- -0.5
- Supercell composite
- -3.1
The text
As transmitted, in the capitals the NWS used until 2016.
527
ACUS11 KWNS 041719
SWOMCD
SPC MCD 041719
TXZ000-041845-
MESOSCALE DISCUSSION 0445
NWS STORM PREDICTION CENTER NORMAN OK
1219 PM CDT WED APR 04 2012
AREAS AFFECTED...MIDDLE AND UPPER TX COAST/COASTAL PLAIN
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 041719Z - 041845Z
POTENTIAL INCREASE IN STORM COVERAGE WITHIN DESTABILIZING AIRMASS
ACROSS THE MIDDLE AND UPPER TX COASTAL REGION COULD REQUIRE WW
ISSUANCE.
LATEST RADAR IMAGERY REVEALS TWO STORMS INVOF THE KHOU /HOUSTON TX/
AREA ATTM...WITH AT LEAST SOME SUPERCELL CHARACTERISTICS EVIDENT.
WITH A MOIST/HEATING BOUNDARY LAYER BENEATH STEEP LAPSE
RATES...ADDITIONAL DESTABILIZATION THIS AFTERNOON WILL PROVIDE A
THERMODYNAMIC ENVIRONMENT INCREASINGLY FAVORABLE FOR ROBUST
CONVECTION.
ALONG WITH THE DESTABILIZING ENVIRONMENT...KHGX /HOUSTON TX/ WSR-88D
VWP CONTINUES TO REVEAL SHEAR SUPPORTIVE OF SUPERCELLS...WITH 50 KT
WSWLYS AT MID LEVELS. THESE FACTORS SUGGEST THAT ANY STORM WHICH
DEVELOPS WILL ORGANIZE/ROTATE...WITH ATTENDANT THREATS FOR LARGE
HAIL AND LOCALLY DAMAGING WINDS.
THE MAIN LIMITING FACTOR ATTM APPEARS TO BE AN OVERALL LACK OF
LARGE-SCALE ASCENT...AS THE MAIN UPPER SYSTEM REMAINS WELL TO THE NW
OVER THE TX PANHANDLE. THOUGH A VERY WEAK FEATURE APPEARS TO BE
MOVING ACROSS NRN MEXICO TOWARD THE LOWER RIO GRANDE VALLEY...THE
MAIN SUPPORT FOR STORM INITIATION APPEARS PRIMARILY AT LOW-LEVELS --
SPECIFICALLY AN OUTFLOW BOUNDARY WHICH HAS NEARLY STALLED JUST W/SW
OF KHGX...A SURFACE FRONT STALLED TO THE W OVER THE COASTAL
PLAIN...AND PERHAPS ALONG A WEAK MARINE FRONT ALONG THE COAST.
WHILE THIS SUGGESTS LIKELIHOOD THAT COVERAGE WILL REMAIN WIDELY
SCATTERED TO ISOLATED...WE WILL CONTINUE TO MONITOR THIS REGION FOR
DEGREE OF CONVECTIVE INITIATION...WHICH -- IF WIDESPREAD ENOUGH --
COULD REQUIRE WW ISSUANCE.
..GOSS.. 04/04/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 29859505 29749463 29009511 28319654 27369738 27609831
28429859 29349819 30629624 30879555 29859505SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 3, 7:35 PM CDT | Severe Thunderstorm Watch | SPC | Austin, Bastrop, Brazos, Burleson, Colorado, Fayette and 13 more | 7 hr |
| Apr 3, 8:47 PM CDT | Mesoscale Discussion | SPC | Angelina, Cherokee, Houston, Nacogdoches, Panola, Rusk and 3 more | 58 min |
| Apr 3, 9:48 PM CDT | Severe Thunderstorm Watch | SPC | Angelina, Cherokee, Hardin, Jasper, Jefferson, Nacogdoches and 8 more | 8 hr |
| Apr 3, 11:24 PM CDT | Mesoscale Discussion | SPC | Angelina, Austin, Colorado, Jasper, Lavaca, Montgomery and 10 more | 96 min |
| Apr 4, 2:29 AM CDT | Mesoscale Discussion | SPC | Chambers, Hardin, Harris, Jefferson, Liberty, Orange and 2 more | 91 min |
| Apr 4, 12:55 PM CDT | Severe Thunderstorm Watch | SPC | Aransas, Bee, Brazoria, Brooks, Calhoun, Cameron and 19 more | 6 hr |
| Apr 4, 3:32 PM CDT | Mesoscale Discussion | SPC | Aransas, Brazoria, Calhoun, Galveston, Kleberg, Matagorda and 1 more | 88 min |
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.