Alert archive / Oklahoma / Mesoscale Discussions in 2009

Mesoscale Discussion 655

May 1, 20099 counties in Arkansas; 26 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at May 1, 2009, 1:22 PM CDT for 9 counties in Arkansas; 26 counties in Oklahoma. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued
May 1, 2009, 1:22 PM CDT (18:22 UTC)
Expired
May 1, 2009, 2:15 PM CDT
In force
53 min
Issued by
the Storm Prediction Center
All 35 counties

Crawford County, AR, Franklin County, AR, Johnson County, AR, Logan County, AR, Montgomery County, AR, Polk County, AR, Scott County, AR, Sebastian County, AR, Washington County, AR, Adair County, OK, Cherokee County, OK, Cleveland County, OK, Creek County, OK, Garfield County, OK, Grant County, OK, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, Lincoln County, OK, Logan County, OK, McIntosh County, OK, Muskogee County, OK, Noble County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Pawnee County, OK, Payne County, OK, Pittsburg County, OK, Pottawatomie County, OK, Seminole County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK

The radar

The Tulsa radar (KINX), 67 km from the middle of the area, began a volume at 18:23 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, 6.4 hours before the alert went out and 154 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, Lamont, OK at 12:00Z on 2009-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1247 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, Lamont, OK at 12:00Z on 2009-05-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 124 square meters per square second.1939Sfc1 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
1247 J/kg
Mixed-layer CIN
-68 J/kg
Mixed-layer LCL
472 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
124 m²/s²
0-3 km storm-relative helicity
230 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 1, 12:45 AM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Crawford, Madison, Washington6 hr
May 1, 3:00 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Crawford, Franklin and 10 more2 hr
May 1, 6:08 AM CDTMesoscale DiscussionSPCBenton, Boone, Carroll, Crawford, Franklin, Johnson and 3 more67 min
May 1, 7:26 AM CDTSevere Thunderstorm WatchSPCCrawford, Franklin, Johnson, Logan, Madison, Montgomery and 5 more7 hr
May 1, 10:32 AM CDTMesoscale DiscussionSPCCrawford, Franklin, Logan, Madison, Washington58 min
May 1, 3:21 PM CDTMesoscale DiscussionSPCBaxter, Boone, Carroll, Clay, Cleburne, Craighead and 23 more54 min
May 1, 3:36 PM CDTSevere Thunderstorm WatchSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 34 more6 hr
May 1, 6:11 PM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 30 more64 min
Apr 30, 7:54 PM CDTSevere Thunderstorm WatchSPCBeckham, Blaine, Caddo, Canadian, Cleveland, Custer and 15 more5 hr
Apr 30, 11:41 PM CDTMesoscale DiscussionSPCBeckham, Blaine, Caddo, Canadian, Cleveland, Custer and 15 more64 min
May 1, 2:48 PM CDTMesoscale DiscussionSPCCarter, Cotton, Jefferson, Love, Murray87 min
May 1, 3:09 PM CDTTornado WatchSPCAtoka, Bryan, Carter, Cleveland, Coal, Comanche and 16 more7 hr

Nearby

Mesoscale Discussions in Oklahoma, 2009Mesoscale Discussions in Arkansas, 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.