Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 559
The Storm Prediction Center issued this mesoscale discussion at Apr 16, 2012, 12:06 PM CDT for 20 counties in Texas. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Apr 16, 2012, 12:06 PM CDT (17:06 UTC)
- Expired
- Apr 16, 2012, 1:30 PM CDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
Counties Aransas County, TX, Bee County, TX, Brooks County, TX, Calhoun County, TX, Cameron County, TX, DeWitt County, TX, Duval County, TX, Goliad County, TX, Hidalgo County, TX, Jim Hogg County, TX, Jim Wells County, TX, Karnes County, TX, Kenedy County, TX, Kleberg County, TX, Live Oak County, TX, Nueces County, TX, Refugio County, TX, San Patricio County, TX, Victoria County, TX, Willacy County, TX
The radar
The Corpus Christi radar (KCRP), 31 km from the middle of the area, began a volume at 17:06 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, 5.1 hours before the alert went out and 40 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
- 2418 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 450 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 121 m²/s²
- 0-3 km storm-relative helicity
- 131 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 5.0
The text
As transmitted, in the capitals the NWS used until 2016.
171
ACUS11 KWNS 161707
SWOMCD
SPC MCD 161706
TXZ000-161830-
MESOSCALE DISCUSSION 0559
NWS STORM PREDICTION CENTER NORMAN OK
1206 PM CDT MON APR 16 2012
AREAS AFFECTED...MIDDLE AND LOWER TX COAST
CONCERNING...SEVERE THUNDERSTORM WATCH 181...
VALID 161706Z - 161830Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 181
CONTINUES.
GREATEST SEVERE WEATHER THREAT COVERAGE FOR HAIL...DAMAGING WINDS
AND AN ISOLATED TORNADO IS EXPECTED TO CONTINUE ACROSS THE CENTRAL
INTO SRN PART OF WW 181 THROUGH THE AFTERNOON. HOWEVER...AN
ISOLATED SEVERE THREAT WILL REMAIN POSSIBLE ACROSS THE NRN EXTENT OF
THIS WATCH...SUPPORTING PRIMARILY A HAIL THREAT...AND REASON NOT TO
CANCEL ANY COUNTIES YET FROM THIS WW.
TRENDS IN LATE MORNING SURFACE OBSERVATIONS AND REGIONAL RADAR
IMAGERY ACROSS THE LOWER-MIDDLE TX COAST REGION SHOWED A COLD FRONT
EXTENDING SWWD FROM THE LOWER MS VALLEY TO THE MIDDLE TX COAST INVOF
KCRP TO NRN JIM HOGG COUNTY IN DEEP S TX. ONGOING CLUSTERS OF TSTMS
ALONG AND N OF THIS FRONT CONTINUE TO EFFECTIVELY SHIFT THIS
BOUNDARY SWD INTO A MORE UNSTABLE AIR MASS...WHERE SURFACE DEWPOINTS
IN THE LOWER 70S AND TEMPERATURES IN THE LOWER-MID 80S ARE
SUPPORTING MLCAPE UP TO 1500 J/KG. THIS INSTABILITY COMBINED WITH
EFFECTIVE BULK SHEAR AROUND 35 KT SUGGESTS MULTICELLS/SUPERCELLS
REMAIN POSSIBLE. FORCING FOR ASCENT WITHIN THE ENTRANCE REGION OF
STRONG MIDLEVEL JET EXTENDING NEWD INTO THE MID MS VALLEY/GREAT
LAKES REGION WILL AID IN SUSTAINING NEW TSTM DEVELOPMENT AS THE
FRONT MOVES INTO DEEP S TX.
MEANWHILE...N OF THE COLD FRONT...MODERATE MUCAPE AND EFFECTIVE BULK
SHEAR UP TO 50 KT ARE SUPPORTIVE OF MAINLY ELEVATED STORMS CAPABLE
OF SOME HAIL THREAT. THUS...THIS SUPPORTS MAINTAINING THE NRN
EXTENT OF WW 181...EVEN THOUGH THE BOUNDARY LAYER HAS BEEN
STABILIZED BY CONVECTIVE PROCESSES.
..PETERS.. 04/16/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...HGX...CRP...EWX...BRO...
LAT...LON 26239870 26879873 27309878 27689916 28049853 28669838
29119798 29209769 29269714 29009685 28119593 27679659
27149694 26379676 25969668 25779738 26239870SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 16, 5:50 AM CDT | Mesoscale Discussion | SPC | Aransas, Calhoun, Nueces, Refugio, San Patricio | 55 min |
| Apr 16, 8:07 AM CDT | Severe Thunderstorm Watch | SPC | Aransas, Bee, Brooks, Calhoun, Cameron, Goliad and 10 more | 7 hr |
| Apr 16, 2:23 PM CDT | Mesoscale Discussion | SPC | Brooks, Cameron, Hidalgo, Kenedy, Willacy | 67 min |
| Apr 16, 3:28 PM CDT | Severe Thunderstorm Watch | SPC | Cameron, Hidalgo, Kenedy, Willacy | 4 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.