Alert archive / Oklahoma / Mesoscale Discussions in 2011
Mesoscale Discussion 430
The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2011, 8:36 PM CDT for 24 counties in Oklahoma; Lamar County, Texas. It was in force for 84 min.
The area
The outline as issued.
The facts
- Issued
- Apr 14, 2011, 8:36 PM CDT (01:36 UTC)
- Expired
- Apr 14, 2011, 10:00 PM CDT
- In force
- 84 min
- Issued by
- the Storm Prediction Center
All 25 counties
Atoka County, OK, Bryan County, OK, Cherokee County, OK, Choctaw County, OK, Coal County, OK, Delaware County, OK, Haskell County, OK, Hughes County, OK, Johnston County, OK, Latimer County, OK, LeFlore County, OK, Marshall County, OK, Mayes County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Pittsburg County, OK, Pontotoc County, OK, Pushmataha County, OK, Rogers County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK, Lamar County, TX
The radar
The Western Arkansas radar (KSRX), 139 km from the middle of the area, began a volume at 01:36 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
Norman, OK (KOUN), launched 00:00Z, 1.6 hours before the alert went out and 153 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
- 4948 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 20 m²/s²
- 0-3 km storm-relative helicity
- 146 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
521 ACUS11 KWNS 150137 SWOMCD SPC MCD 150136 OKZ000-TXZ000-150300- MESOSCALE DISCUSSION 0430 NWS STORM PREDICTION CENTER NORMAN OK 0836 PM CDT THU APR 14 2011 AREAS AFFECTED...ERN OK/FAR NERN TX CONCERNING...TORNADO WATCH 135... VALID 150136Z - 150300Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 135 CONTINUES. THE THREAT FOR SEVERE THUNDERSTORMS AND TORNADOES WILL LIKELY PERSIST BEYOND THE EXPIRATION TIME OF 03Z ACROSS SERN AND E-CNTRL OK AND FAR NERN TX. IN THESE AREAS...A NEW TORNADO WATCH WILL BE NEEDED. EARLY EVENING SFC ANALYSIS INDICATES THAT THE COLD FRONT HAD OVERTAKEN THE DRYLINE ACROSS NRN OK...AND EXTENDED FROM NRN OSAGE COUNTY TO THE INTERSECTION OF THE DRYLINE JUST SE OF THE OKC METRO AREA. THE DRYLINE EXTENDED FARTHER S-SW FROM THIS JUNCTURE TO THE RED RIVER NEAR INTERSTATE 35 AND INTO N-CNTRL TX. AS THE COLD FRONT CONTINUES TO ACCELERATE EWD ACROSS NERN OK...THE SEVERE THREAT WILL LIKELY HAVE SHIFTED INTO NWRN AR BY 03Z. HOWEVER...GIVEN THE NE-SW ORIENTATION OF THE OVERTAKING COLD FRONT...THE WARM/UNSTABLE SECTOR FEATURING MLCAPE VALUES OF 1500-2500 J/KG WILL PERSIST ACROSS SERN/E-CNTRL OK PAST 03Z. THIS AMOUNT OF INSTABILITY...JUXTAPOSED WITH EFFECTIVE STORM-RELATIVE HELICITY VALUES OF 200-400 M2/S2 /NOTABLY INCREASING/...WILL SUPPORT PERSISTENCE OF THE DISCRETE AND SEMI-DISCRETE SUPERCELL MODE WITH AN ATTENDANT THREAT FOR TORNADOES...DAMAGING WINDS...AND LARGE HAIL. THE THREAT FOR STRONG TORNADOES WILL CONTINUE OVER THE NEXT FEW HOURS WITH THE MOST DISCRETE CONVECTION AND UNDISTURBED INFLOW -- I.E. ACROSS THE SRN TWO TIERS OF COUNTIES OF SERN OK AND ADJACENT COUNTIES OF FAR NERN TX. ..COHEN.. 04/15/2011 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...SHV...TSA...FWD...OUN... LAT...LON 33869728 33619513 34559449 36459472 36669580 33869728
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 14, 9:06 PM CDT | Tornado Watch | SPC | Adair, Atoka, Bryan, Cherokee, Choctaw, Coal and 18 more | 6 hr |
| Apr 14, 11:11 PM CDT | Mesoscale Discussion | SPC | Adair, Cherokee, Choctaw, Delaware, Haskell, Latimer and 4 more | 94 min |
| Apr 14, 9:59 PM CDT | Mesoscale Discussion | SPC | Collin, Dallas, Denton, Hopkins, Hunt, Rockwall | 31 min |
| Apr 14, 10:04 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Collin, Coryell, Dallas, Denton and 19 more | 4 hr |
| Apr 14, 11:24 PM CDT | Severe Thunderstorm Watch | SPC | Camp, Cass, Cherokee, Gregg, Harrison, Marion and 7 more | 3 hr |
| Apr 14, 11:56 PM CDT | Mesoscale Discussion | SPC | Anderson, Camp, Cass, Cherokee, Ellis, Freestone and 16 more | 94 min |
| Apr 15, 2:19 AM CDT | Tornado Watch | SPC | Cherokee, Harrison, Nacogdoches, Panola, Rusk, Shelby | 8 hr |
Nearby
Mesoscale Discussions in Oklahoma, 2011Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011
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.