Alert archive / Oklahoma / Mesoscale Discussions in 2009
Mesoscale Discussion 1908
The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2009, 8:34 PM CDT for 17 counties in Oklahoma; 9 counties in Texas. It was in force for 56 min.
The area
The outline as issued.
The facts
- Issued
- Aug 17, 2009, 8:34 PM CDT (01:34 UTC)
- Expired
- Aug 17, 2009, 9:30 PM CDT
- In force
- 56 min
- Issued by
- the Storm Prediction Center
All 26 counties
Beckham County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Grant County, OK, Greer County, OK, Harmon County, OK, Kay County, OK, Kingfisher County, OK, Kiowa County, OK, Logan County, OK, Major County, OK, Noble County, OK, Washita County, OK, Carson County, TX, Collingsworth County, TX, Donley County, TX, Gray County, TX, Hutchinson County, TX, Moore County, TX, Roberts County, TX, Sherman County, TX, Wheeler County, TX
The radar
The Vance AFB radar (KVNX), 144 km from the middle of the area, began a volume at 01:34 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
Lamont, OK (KLMN), launched 00:00Z, 1.6 hours before the alert went out and 187 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
- 1107 J/kg
- Mixed-layer CIN
- -151 J/kg
- Mixed-layer LCL
- 1021 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 118 m²/s²
- 0-3 km storm-relative helicity
- 251 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 12.0
The text
As transmitted, in the capitals the NWS used until 2016.
556
ACUS11 KWNS 180135
SWOMCD
SPC MCD 180134
OKZ000-KSZ000-TXZ000-180230-
MESOSCALE DISCUSSION 1908
NWS STORM PREDICTION CENTER NORMAN OK
0834 PM CDT MON AUG 17 2009
AREAS AFFECTED...TX PANHANDLE...WRN/NRN OK
CONCERNING...SEVERE THUNDERSTORM WATCH 708...
VALID 180134Z - 180230Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 708
CONTINUES.
MCS IS GRADUALLY EXPANDING IN AREAL COVERAGE OVER THE SRN PLAINS
FROM THE ERN TX PANHANDLE...INTO WCNTRL OK. IT APPEARS A
SIGNIFICANT COLD POOL...SUFFICIENT ENOUGH TO ALTER FORWARD
PROPAGATION COMPONENT...HAS DEVELOPED BENEATH THE EXPANDING
PRECIPITATION AND IS DRIVING LEADING EDGE OF CONVECTION AT ROUGHLY
30KT ACROSS CUSTER/BECKHAM COUNTIES IN OK. 00Z SOUNDING FROM OUN
EXHIBITED A THERMODYNAMIC ENVIRONMENT FAVORABLE FOR STORM
MAINTENANCE...THOUGH VERTICAL SHEAR IS SOMEWHAT MARGINAL. GIVEN
THAT THE LLJ WILL REMAIN ESTABLISHED ACROSS THE HIGH PLAINS OVER THE
TX PANHANDLE...IT APPEARS STORM-SCALE PROCESSES...NAMELY
OUTFLOW...WILL STEER MCS ACROSS WRN/NRN OK INTO PORTIONS OF CNTRL OK
OVER THE NEXT FEW HOURS. IF CONVECTION REMAINS STRONG/SEVERE...A
LOCAL EXTENSION TO WW708 MAY BE NEEDED ACROSS THIS REGION.
FARTHER WEST...LONG LIVED SUPERCELL CONTINUES DIGGING SEWD ACROSS
THE NWRN TX PANHANDLE THROUGH DALLAM INTO SHERMAN COUNTY. WITH LLJ
EXPECTED TO INCREASE AHEAD OF THIS STORM ATOP COOLER RAIN-COOLED
AIRMASS...IT WOULD SEEM ADDITIONAL ELEVATED THUNDERSTORMS COULD
DEVELOP AHEAD OF THIS STRONG STORM. AS ACROSS CNTRL OK...A LOCAL
EXTENSION MAY BE REQUIRED FOR THE NERN HALF OF THE TX PANHANDLE.
..DARROW.. 08/18/2009
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...TSA...ICT...OUN...LUB...AMA...
LAT...LON 36729655 35499756 34799916 34570057 35340144 36180265
36590200 35540008 36049904 37029741 36729655SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 4:46 PM CDT | Mesoscale Discussion | SPC | Cimarron, Texas | 59 min |
| Aug 18, 5:00 PM CDT | Severe Thunderstorm Watch | SPC | Beaver, Cimarron, Texas | 7 hr |
Nearby
Mesoscale Discussions in Oklahoma, 2009Mesoscale Discussions in Texas, 2009Every mesoscale discussion in 2009
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.