Alert archive / Oklahoma / Mesoscale Discussions in 2004

Mesoscale Discussion 417

April 21, 200449 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2004, 6:02 PM CDT for 49 counties in Oklahoma. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued
Apr 21, 2004, 6:02 PM CDT (23:02 UTC)
Expired
Apr 21, 2004, 7:30 PM CDT
In force
88 min
Issued by
the Storm Prediction Center
All 49 counties

Adair County, OK, Alfalfa County, OK, Atoka County, OK, Blaine County, OK, Canadian County, OK, Cherokee County, OK, Cleveland County, OK, Coal County, OK, Creek County, OK, Delaware County, OK, Dewey County, OK, Ellis County, OK, Garfield County, OK, Garvin County, OK, Grant County, OK, Harper County, OK, Haskell County, OK, Hughes County, OK, Johnston County, OK, Kingfisher County, OK, Latimer County, OK, Lincoln County, OK, Logan County, OK, Major County, OK, Mayes County, OK, McClain County, OK, McCurtain County, OK, McIntosh County, OK, Murray County, OK, Muskogee County, OK, Noble County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Pittsburg County, OK, Pontotoc County, OK, Pottawatomie County, OK, Pushmataha County, OK, Roger Mills County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK, Woods County, OK, Woodward County, OK

The radar

The Norman radar (KTLX), 14 km from the middle of the area, began a volume at 23:03 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 12:00Z, 11.0 hours before the alert went out and 30 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 12:00Z on 2004-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 123 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 12:00Z on 2004-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -51 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
123 J/kg
Mixed-layer CIN
-217 J/kg
Mixed-layer LCL
1714 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-51 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

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
Apr 20, 7:22 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Craig, Creek, Delaware, Kay and 12 more23 min
Apr 20, 7:50 PM CDTTornado WatchSPCAdair, Cherokee, Cleveland, Craig, Creek, Delaware and 13 more5 hr
Apr 20, 8:57 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Cleveland, Craig, Creek, Delaware and 13 more2 hr
Apr 20, 10:39 PM CDTMesoscale DiscussionSPCHaskell, Hughes, Latimer, LeFlore, McIntosh, Muskogee and 6 more3 hr
Apr 20, 10:57 PM CDTMesoscale DiscussionSPCAdair, Cherokee, Cleveland, Craig, Creek, Delaware and 13 more93 min
Apr 21, 12:58 PM CDTMesoscale DiscussionSPCAtoka, Beckham, Blaine, Bryan, Caddo, Canadian and 34 more2 hr
Apr 21, 1:50 PM CDTTornado WatchSPCAdair, Alfalfa, Atoka, Beckham, Blaine, Caddo and 55 more7 hr
Apr 21, 1:56 PM CDTMesoscale DiscussionSPCBeaver, Cimarron, Texas94 min
Apr 21, 3:00 PM CDTSevere Thunderstorm WatchSPCBeaver, Cimarron, Texas6 hr
Apr 21, 4:39 PM CDTMesoscale DiscussionSPCAdair, Alfalfa, Atoka, Beckham, Blaine, Caddo and 47 more66 min
Apr 21, 5:09 PM CDTMesoscale DiscussionSPCBeaver, Cimarron, Texas66 min

Nearby

Mesoscale Discussions in Oklahoma, 2004Every mesoscale discussion in 2004

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.