Alert archive / Oklahoma / Mesoscale Discussions in 2012
Mesoscale Discussion 137
The Storm Prediction Center issued this mesoscale discussion at Feb 20, 2012, 1:39 PM CST for 17 counties in Kansas; 29 counties in Oklahoma; Clay County, Wichita County, Texas. It was in force for 66 min.
The area
The outline as issued.
The facts
- Issued
- Feb 20, 2012, 1:39 PM CST (19:39 UTC)
- Expired
- Feb 20, 2012, 2:45 PM CST
- In force
- 66 min
- Issued by
- the Storm Prediction Center
All 48 counties
Barber County, KS, Barton County, KS, Butler County, KS, Cowley County, KS, Ellsworth County, KS, Harper County, KS, Harvey County, KS, Kingman County, KS, Marion County, KS, McPherson County, KS, Pratt County, KS, Reno County, KS, Rice County, KS, Saline County, KS, Sedgwick County, KS, Stafford County, KS, Sumner County, KS, Alfalfa County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Carter County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Garfield County, OK, Garvin County, OK, Grady County, OK, Grant County, OK, Jefferson County, OK, Kay County, OK, Kingfisher County, OK, Lincoln County, OK, Logan County, OK, Love County, OK, Major County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Noble County, OK, Oklahoma County, OK, Pawnee County, OK, Payne County, OK, Pontotoc County, OK, Pottawatomie County, OK, Stephens County, OK, Clay County, TX, Wichita County, TX
The radar
The Vance AFB radar (KVNX), 30 km from the middle of the area, began a volume at 19:39 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
Lamont, OK (KLMN), launched 12:00Z, 7.7 hours before the alert went out and 57 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 887 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 430 m²/s²
- 0-3 km storm-relative helicity
- 464 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
312
ACUS11 KWNS 201940
SWOMCD
SPC MCD 201939
KSZ000-OKZ000-TXZ000-202045-
MESOSCALE DISCUSSION 0137
NWS STORM PREDICTION CENTER NORMAN OK
0139 PM CST MON FEB 20 2012
AREAS AFFECTED...CENTRAL KS SWD ACROSS WRN AND CENTRAL OK TO N
CENTRAL TX
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 201939Z - 202045Z
CONVECTIVE/SEVERE POTENTIAL WILL CONTINUE TO SLOWLY INCREASE THIS
AFTERNOON...WITH WW POSSIBLE.
LATEST SURFACE AND OBJECTIVE ANALYSES INDICATE A ZONE OF SLOW
DESTABILIZATION EXTENDING FROM CENTRAL KS SWD ACROSS W CENTRAL AND
CENTRAL OK INTO N TX...AHEAD OF COLD FRONT NOW CROSSING WRN KS AND
THE OK/TX PANHANDLES. VISIBLE SATELLITE SHOWS WEAK CONVECTION
EXPANDING ACROSS WRN KS/WRN OK INVOF THE SURFACE FRONT...BUT THIS
CONVECTION IS OCCURRING WITHIN A MORE MIXED AIRMASS WHERE SURFACE
FLOW HAS VEERED OVER THE PAST HOUR OR SO. WITH THE LEADING EDGE OF
THE MORE DEEPLY MIXED BOUNDARY LAYER NOW APPROACHING CENTRAL OK/S
CENTRAL KS...EXPECT STRONGEST STORMS TO EVENTUALLY EVOLVE AHEAD OF
THE SURFACE FRONT -- NEARER TO THIS EVOLVING SURFACE TROUGH/DRYLINE.
DEWPOINTS REMAIN FAIRLY LOW AT THE SURFACE -- UPPER 40S OR LESS
ACROSS THE ENTIRE REGION -- AND ARE EXPECTED TO REMAIN SO...OR EVEN
DECREASE SLIGHTLY. THUS...EXPECTED MODEST AIRMASS DESTABILIZATION
WILL BE THE RESULT OF WARM SECTOR HEATING WITHIN THE DRY
SLOT...COMBINED WITH THE EWD SPREAD OF STEEP LAPSE RATES ALOFT AS
VERY COLD /-20S C/ MID LEVEL AIR ACCOMPANIES THIS SYSTEM.
STRONG FLOW ALOFT AND FAVORABLE VEERING/SHEAR WITH HEIGHT WITHIN THE
LOWER HALF OF THE TROPOSPHERE IN CONJUNCTION WITH THE OVERALL
STRENGTH OF THE UPPER SYSTEM SUGGESTS THE EVENTUAL EVOLUTION OF
SCATTERED/SMALL/LOW-TOPPED SUPERCELLS...DESPITE THE RELATIVELY
LIMITED CAPE. GIVEN THE WARMING/MIXING BOUNDARY LAYER...TORNADO
POTENTIAL SHOULD REMAIN LIMITED/ISOLATED. HOWEVER...HAIL IS
EXPECTED ALONG WITH SOME THREAT FOR LOCAL WIND DAMAGE...WITH WIND
THREAT BECOMING ENHANCED IF UPSCALE GROWTH INTO LINE SEGMENTS/BOWS
CAN OCCUR. STORMS WILL LIKELY BE SLOW TO EVOLVE/INTENSIFY...AND
THUS UNCERTAINTY REMAINS REGARDING TIMING OF POSSIBLE WW ISSUANCE.
..GOSS.. 02/20/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...TSA...TOP...ICT...FWD...OUN...DDC...
LAT...LON 33849884 34999863 36499866 37319881 37959907 38899925
38959810 38809720 38539689 36839645 33989673 33729778
33849884SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 20, 2:50 PM CST | Severe Thunderstorm Watch | SPC | Butler, Chase, Chautauqua, Cowley, Elk, Greenwood and 8 more | 4 hr |
| Feb 20, 4:50 PM CST | Mesoscale Discussion | SPC | Allen, Bourbon, Cherokee, Crawford, Labette, Montgomery and 3 more | 55 min |
| Feb 20, 5:01 PM CST | Severe Thunderstorm Watch | SPC | Allen, Bourbon, Cherokee, Crawford, Labette, Montgomery and 3 more | 4 hr |
| Feb 20, 5:33 PM CST | Mesoscale Discussion | SPC | Clay, Cloud, Marshall, Republic, Riley, Washington | 57 min |
| Feb 20, 5:37 PM CST | Mesoscale Discussion | SPC | Allen, Anderson, Bourbon, Chautauqua, Cherokee, Coffey and 20 more | 113 min |
Nearby
Mesoscale Discussions in Oklahoma, 2012Mesoscale Discussions in Kansas, 2012Mesoscale 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.