Alert archive / Oklahoma / Mesoscale Discussions in 2017

Mesoscale Discussion 582

April 28, 201724 counties in Oklahoma; 8 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2017, 10:18 PM CDT for 24 counties in Oklahoma; 8 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2017, 10:18 PM CDT (03:18 UTC)
Expired
Apr 29, 2017, 12:15 AM CDT
In force
117 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 32 counties

Beckham County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Garvin County, OK, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kingfisher County, OK, Kiowa County, OK, Lincoln County, OK, Logan County, OK, McClain County, OK, Oklahoma County, OK, Pottawatomie County, OK, Roger Mills County, OK, Stephens County, OK, Tillman County, OK, Washita County, OK, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Foard County, TX, Hall County, TX, Hardeman County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 52 km from the middle of the area, began a volume at 03:19 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, 3.3 hours before the alert went out and 149 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.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 2017-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 788 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 00:00Z on 2017-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
788 J/kg
Mixed-layer CIN
-86 J/kg
Mixed-layer LCL
1197 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
261 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.7

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 28, 10:01 PM CDTSevere Thunderstorm WatchSPCAdair, Cherokee, Craig, Creek, Delaware, Haskell and 17 more9 hr
Apr 28, 10:35 PM CDTSevere Thunderstorm WatchSPCBeckham, Blaine, Caddo, Canadian, Cleveland, Comanche and 21 more8 hr
Apr 29, 2:45 AM CDTMesoscale DiscussionSPCBeckham, Blaine, Caddo, Canadian, Cleveland, Comanche and 21 more2 hr
Apr 29, 3:39 AM CDTMesoscale DiscussionSPCAdair, Cherokee, Craig, Creek, Delaware, Mayes and 7 more96 min
Apr 29, 4:04 AM CDTMesoscale DiscussionSPCCimarron6 hr
Apr 29, 1:11 PM CDTMesoscale DiscussionSPCAdair, Haskell, Latimer, LeFlore, McCurtain, Pushmataha and 1 more2 hr
Apr 29, 2:10 PM CDTMesoscale DiscussionSPCBryan, Marshall2 hr
Apr 29, 5:36 PM CDTSevere Thunderstorm WatchSPCAdair, Choctaw, Haskell, Latimer, LeFlore, Pushmataha and 1 more4 hr
Apr 29, 9:19 AM CDTMesoscale DiscussionSPCHardin, Jasper, Newton, Orange, Sabine, Tyler116 min
Apr 29, 5:10 PM CDTTornado WatchSPCAnderson, Camp, Cherokee, Delta, Fannin, Franklin and 18 more5 hr
Apr 29, 6:31 PM CDTMesoscale DiscussionSPCBastrop, Caldwell, Falls, Lee, Milam, Travis and 1 more59 min
Apr 29, 6:50 PM CDTSevere Thunderstorm WatchSPCAustin, Bastrop, Bell, Brazos, Burleson, Caldwell and 20 more4 hr

Nearby

Mesoscale Discussions in Oklahoma, 2017Mesoscale Discussions in Texas, 2017Every mesoscale discussion in 2017

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.