Alert archive / Oklahoma / Mesoscale Discussions in 2004

Mesoscale Discussion 404

April 20, 20045 counties in Arkansas; 4 counties in Missouri; 19 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2004, 10:57 PM CDT for 5 counties in Arkansas; 4 counties in Missouri; 19 counties in Oklahoma. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2004, 10:57 PM CDT (03:57 UTC)
Expired
Apr 21, 2004, 12:30 AM CDT
In force
93 min
Issued by
the Storm Prediction Center
All 28 counties

Benton County, AR, Carroll County, AR, Crawford County, AR, Madison County, AR, Washington County, AR, Barry County, MO, McDonald County, MO, Stone County, MO, Taney County, MO, Adair County, OK, Cherokee County, OK, Cleveland County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Haskell County, OK, Mayes County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Ottawa County, OK, Pottawatomie County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK

The radar

The Western Arkansas radar (KSRX), 100 km from the middle of the area, began a volume at 03:56 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 nearest sounding before it

Springfield, MO (KSGF), launched 00:00Z, 4.0 hours before the alert went out and 97 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, Springfield, MO at 00:00Z on 2004-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 40 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, Springfield, MO at 00:00Z on 2004-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 147 square meters per square second.19395878Sfc1 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
40 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
860 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
147 m²/s²
0-3 km storm-relative helicity
176 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.

711 
ACUS11 KWNS 210358
SWOMCD
SPC MCD 210357 
MOZ000-ARZ000-OKZ000-210530-

MESOSCALE DISCUSSION 0404
NWS STORM PREDICTION CENTER NORMAN OK
1057 PM CDT TUE APR 20 2004

AREAS AFFECTED...PORTIONS E-CENTRAL/NERN OK AND NWRN AR

CONCERNING...TORNADO WATCH 97...

VALID 210357Z - 210530Z

AS OF 4Z...SCATTERED POTENTIALLY SEVERE TSTMS CONTINUE FROM FYV/ROG
AREA OF NW AR SWWD TOWARD OKFUSKEE COUNTY OK.  ACTIVITY SHOULD SHIFT
EWD ACROSS REMAINDER WW AREA...NRN PORTION WEAKENING AS IT MOVES
FURTHER INTO OZARKS.  OVERALL SEVERE THREAT APPEARS TO BE TRENDING
DOWN BUT STILL IS SUFFICIENT TO MAINTAIN WW ALONG/AHEAD OF BAND.

SFC ANALYSIS SHOWS DRYLINE RETREATING WWD ACROSS CENTRAL OK AND AWAY
FROM ONGOING CONVECTION OVER ERN/NERN OK.  250-400 J/KG SRH STILL
EVIDENT IN 0-3 KM AGL LAYER...AND NEARLY SFC BASED SUPERCELLS REMAIN
POSSIBLE...PARTICULARLY NEAR SRN EDGE OF CONVECTIVE COMPLEX. 
ACTIVITY MOVING EWD FROM MCINTOSH/OKFUSKEE COUNTIES MAY INTENSIFY AS
IT INTERACTS WITH OUTFLOW BOUNDARIES FROM STORMS FARTHER E/NE. 
HOWEVER...SUPERCELL TORNADO PROBABILITIES SHOULD CONTINUE TO
DIMINISH THROUGH REMAINDER TONIGHT AS BOUNDARY LAYER INSTABILITY
LESSENS...AND AS MORE LINEAR CONVECTIVE MODE DOMINATES.  HEAVY
RAINFALL POTENTIAL ALSO EXISTS WITH SOME OF THIS CONVECTION...REF
SPC MESOSCALE DISCUSSION 403 FOR DETAILS.

..EDWARDS.. 04/21/2004

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LZK...SGF...TSA...OUN...

36889238 35149464 35149742 36899526

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 7:22 PM CDTMesoscale DiscussionSPCBenton, Madison, Washington23 min
Apr 20, 7:50 PM CDTTornado WatchSPCBenton, Carroll, Crawford, Madison, Washington5 hr
Apr 20, 8:57 PM CDTMesoscale DiscussionSPCBenton, Carroll, Crawford, Madison, Washington2 hr
Apr 20, 10:39 PM CDTMesoscale DiscussionSPCCrawford, Franklin, Scott, Sebastian3 hr
Apr 21, 2:13 PM CDTMesoscale DiscussionSPCBaxter, Boone, Clark, Cleburne, Cleveland, Conway and 30 more92 min
Apr 21, 2:40 PM CDTTornado WatchSPCArkansas, Ashley, Baxter, Benton, Boone, Bradley and 52 more6 hr
Apr 21, 4:40 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Baxter, Benton, Boone, Bradley and 52 more95 min
Apr 21, 6:29 PM CDTMesoscale DiscussionSPCArkansas, Baxter, Benton, Boone, Carroll, Chicot and 25 more91 min
Apr 20, 7:20 PM CDTMesoscale DiscussionSPCAdair, Audrain, Bates, Benton, Boone, Caldwell and 38 more115 min
Apr 20, 8:06 PM CDTMesoscale DiscussionSPCAtchison84 min
Apr 20, 9:38 PM CDTMesoscale DiscussionSPCAudrain, Boone, Callaway, Cole, Crawford, Dent and 16 more37 min
Apr 20, 11:10 PM CDTMesoscale DiscussionSPCCrawford, Dent, Franklin, Gasconade, Iron, Jefferson and 9 more2 hr
Apr 21, 2:58 PM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Mississippi, New Madrid, Pemiscot and 4 more92 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
Apr 21, 6:02 PM CDTMesoscale DiscussionSPCAdair, Alfalfa, Atoka, Blaine, Canadian, Cherokee and 43 more88 min

Nearby

Mesoscale Discussions in Oklahoma, 2004Mesoscale Discussions in Arkansas, 2004Mesoscale Discussions in Missouri, 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.