Alert archive / Texas / Mesoscale Discussions in 2012
Mesoscale Discussion 1997
The Storm Prediction Center issued this mesoscale discussion at Sep 27, 2012, 2:17 PM CDT for 28 counties in Texas. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Sep 27, 2012, 2:17 PM CDT (19:17 UTC)
- Expired
- Sep 27, 2012, 3:15 PM CDT
- In force
- 58 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 28 counties
Brown County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Crane County, TX, Eastland County, TX, Ector County, TX, Fisher County, TX, Glasscock County, TX, Howard County, TX, Irion County, TX, Jones County, TX, Martin County, TX, Midland County, TX, Mitchell County, TX, Nolan County, TX, Palo Pinto County, TX, Reagan County, TX, Runnels County, TX, Scurry County, TX, Shackelford County, TX, Stephens County, TX, Sterling County, TX, Taylor County, TX, Tom Green County, TX, Upton County, TX, Young County, TX
The radar
The San Angelo radar (KSJT), 112 km from the middle of the area, began a volume at 19:17 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
Midland Regional, TX (KMAF), launched 12:00Z, 7.3 hours before the alert went out and 165 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
- 1355 J/kg
- Mixed-layer CIN
- -46 J/kg
- Mixed-layer LCL
- 656 m above ground
- 0-6 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 95 m²/s²
- 0-3 km storm-relative helicity
- 117 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
762
ACUS11 KWNS 271917
SWOMCD
SPC MCD 271917
TXZ000-272015-
MESOSCALE DISCUSSION 1997
NWS STORM PREDICTION CENTER NORMAN OK
0217 PM CDT THU SEP 27 2012
AREAS AFFECTED...TX S PLAINS...PERMIAN BASIN...WRN N TX
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 271917Z - 272015Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...TSTM DEVELOPMENT IS EXPECTED TO CONTINUE AS AN OUTFLOW
BOUNDARY MOVES SWD ACROSS THE TX S PLAINS AND INTO THE PERMIAN
BASIN. PRIMARY THREAT ACROSS THIS AREA IS HEAVY RAINFALL WITH RATES
EXCEEDING 2 INCHES/HOUR POSSIBLE. SEVERE THREAT IS LOW AND A WW IS
NOT NEEDED.
DISCUSSION...LOW-LEVEL CONVERGENCE CONTINUES ON A SWD/SEWD
PROGRESSING COLD POOL /DEPICTED AS A COLD FRONT ON THE MD GRAPHIC/
ACROSS THE TX S PLAINS...PERMIAN BASIN...AND WRN N TX. THIS
LOW-LEVEL CONVERGENCE IS EXPECTED TO CONTINUE AS THE SWD/SEWD
PROGRESSION GRADUALLY SLOWS. ADDITIONALLY...CONTINUED MOISTURE
TRANSPORT...SUPPORTED BY ENHANCED 850 MB SLY FLOW AND ML MIXING
RATIOS AROUND 15 G/KG...IN CONJUNCTION WITH UPWIND PROPAGATION ALONG
THE BOUNDARY WILL SUPPORT HIGH RAINFALL EFFICIENCY AND VERY HEAVY
RAINFALL. RAINFALL RATES MAY BRIEFLY EXCEED 2 INCHES/HR WITH SOME
FLASH FLOODING POSSIBLE.
STEEP LOW-LEVEL LAPSE RATES /GREATER THAN 8 DEG C PER KM BASED ON
THE LATEST MESOANALYSIS/ DO EXIST ACROSS THE PERMIAN BASIN AND THE
MAF 12Z RAOB DID SHOW MODERATE MID-LEVEL LAPSE RATES SO THE SEVERE
THREAT CANNOT BE ENTIRELY RULED OUT. HOWEVER...WEAK SHEAR IS
EXPECTED TO PRECLUDE TSTM ORGANIZATION AND KEEP THE OVERALL SEVERE
POTENTIAL LOW. AS SUCH...A WW IS NOT ANTICIPATED.
..MOSIER/MEAD.. 09/27/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...FWD...SJT...MAF...
LAT...LON 31950279 32280244 32690165 32890003 33099912 33199873
33099814 32529808 31409880 31140312 31950279SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 26, 10:29 PM CDT | Mesoscale Discussion | SPC | Lipscomb, Ochiltree | 61 min |
| Sep 27, 3:09 PM CDT | Mesoscale Discussion | SPC | Dallam, Hartley, Oldham | 66 min |
| Sep 27, 5:59 PM CDT | Severe Thunderstorm Watch | SPC | Dallam, Hansford, Hartley, Ochiltree, Sherman | 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.