Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 2163
The Storm Prediction Center issued this mesoscale discussion at Dec 16, 2012, 1:51 PM CST for 6 counties in Texas. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Dec 16, 2012, 1:51 PM CST (19:51 UTC)
- Expired
- Dec 16, 2012, 3:15 PM CST
- In force
- 84 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
Counties Aransas County, TX, Calhoun County, TX, Jackson County, TX, Matagorda County, TX, Refugio County, TX, Victoria County, TX
The radar
The Houston radar (KHGX), 151 km from the middle of the area, began a volume at 19:50 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
Corpus Christi, TX (KCRP), launched 12:00Z, 7.9 hours before the alert went out and 145 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
- 1579 J/kg
- Mixed-layer CIN
- -67 J/kg
- Mixed-layer LCL
- 517 m above ground
- 0-6 km bulk shear
- 69 kt
- 0-1 km storm-relative helicity
- 142 m²/s²
- 0-3 km storm-relative helicity
- 157 m²/s²
- Significant tornado parameter
- 1.1
- Supercell composite
- 5.2
The text
As transmitted, in the capitals the NWS used until 2016.
190
ACUS11 KWNS 161951
SWOMCD
SPC MCD 161951
TXZ000-162115-
MESOSCALE DISCUSSION 2163
NWS STORM PREDICTION CENTER NORMAN OK
0151 PM CST SUN DEC 16 2012
AREAS AFFECTED...THE MIDDLE TX COAST
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 161951Z - 162115Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...ISOLATED STRONG/SEVERE STORM DEVELOPMENT IS POSSIBLE NEAR
THE INTERSECTION OF A SURFACE TROUGH AND AN OUTFLOW BOUNDARY.
DAMAGING GUSTS AND MARGINALLY SEVERE HAIL MAY OCCUR WITH THE
STRONGEST STORMS...THOUGH THE NEED FOR A WATCH IS UNCERTAIN.
DISCUSSION...RADAR AND VISIBLE IMAGERY SHOW NEW CONVECTION
DEVELOPING NEAR VCT AT THE INTERSECTION OF AN OUTFLOW BOUNDARY FROM
THE MORNING CONVECTION...AND A MORE NNE-SSW ORIENTED SURFACE TROUGH.
SURFACE TEMPERATURES AND DEWPOINTS IN THE UPPER 70S AND NEAR
70...RESPECTIVELY...ARE CONTRIBUTING TO MLCAPE OF AT LEAST 1500
J/KG. DEEP-LAYER WSWLY VERTICAL SHEAR IS SUFFICIENT FOR SUPERCELLS
ACROSS THIS AREA...AND THE MORE INTENSE STORMS COULD PRODUCE
ISOLATED DAMAGING GUSTS AND MARGINALLY SEVERE HAIL.
ADDITIONALLY...LOW-LEVEL SHEAR IS SOMEWHAT STRONGER ALONG THE
RESIDUAL OUTFLOW BOUNDARY...SUCH THAT A BRIEF TORNADO CANNOT BE
RULED OUT. THE COVERAGE OF SEVERE STORMS IS IN QUESTION THIS
AFTERNOON...THOUGH A SMALL WATCH COULD BE NEEDED ACROSS PARTS OF THE
MIDDLE TX COAST.
..THOMPSON/CORFIDI.. 12/16/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...HGX...CRP...
LAT...LON 28309634 28039705 28159730 28439741 29049692 29219672
29299639 29199586 29119544 28839528 28719544 28309634SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 16, 5:00 AM CST | Mesoscale Discussion | SPC | Angelina, Austin, Brazos, Burleson, Chambers, Colorado and 29 more | 90 min |
| Dec 16, 5:48 AM CST | Severe Thunderstorm Watch | SPC | Angelina, Austin, Bastrop, Brazoria, Brazos, Burleson and 38 more | 7 hr |
| Dec 16, 9:54 AM CST | Mesoscale Discussion | SPC | Brazoria, Calhoun, Chambers, Galveston, Jackson, Jefferson and 3 more | 96 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.