Alert archive / Missouri / Mesoscale Discussions in 2004

Mesoscale Discussion 397

April 20, 200425 counties in Iowa; 44 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2004, 7:20 PM CDT for 25 counties in Iowa; 44 counties in Missouri. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2004, 7:20 PM CDT (00:20 UTC)
Expired
Apr 20, 2004, 9:15 PM CDT
In force
115 min
Issued by
the Storm Prediction Center
All 69 counties

Appanoose County, IA, Clarke County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Henry County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Adair County, MO, Audrain County, MO, Bates County, MO, Benton County, MO, Boone County, MO, Caldwell County, MO, Callaway County, MO, Carroll County, MO, Cass County, MO, Chariton County, MO, Clark County, MO, Clay County, MO, Clinton County, MO, Cole County, MO, Cooper County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Henry County, MO, Howard County, MO, Jackson County, MO, Johnson County, MO, Knox County, MO, Lafayette County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Mercer County, MO, Moniteau County, MO, Monroe County, MO, Morgan County, MO, Pettis County, MO, Putnam County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO, Worth County, MO

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 0.3 hours before the alert went out and 206 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, Topeka, KS at 00:00Z on 2004-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Topeka, KS at 00:00Z on 2004-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 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
1 J/kg
Mixed-layer CIN
-187 J/kg
Mixed-layer LCL
1520 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
38 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

056 
ACUS11 KWNS 210020
SWOMCD
SPC MCD 210020 
IAZ000-MOZ000-KSZ000-210215-

MESOSCALE DISCUSSION 0397
NWS STORM PREDICTION CENTER NORMAN OK
0720 PM CDT TUE APR 20 2004

AREAS AFFECTED...CENTRAL/NRN MO AND S-CENTRAL IA

CONCERNING...SEVERE THUNDERSTORM WATCH 94...

VALID 210020Z - 210215Z

WW 94 CONTINUES IN EFFECT ACROSS CENTRAL/NRN MO AND S-CENTRAL IA
THROUGH 03Z. 

AT 21/00Z...SOLID CONVECTIVE LINE CONTINUES FROM NEAR IRK SWWD INTO
FAR SERN KS...IN VICINITY OF SURFACE TROUGH ALONG THIS AXIS. PRIMARY
SUPPORT FOR ACTIVITY IS STRONG UPPER TROUGH EVIDENT ON WV IMAGERY
MOVING EWD ACROSS OK AT THE PRESENT TIME. LIMITED SURFACE HEATING
DOWNSTREAM OF CONVECTIVE LINE ACROSS CENTRAL MO HAS NOT ALLOWED AIR
MASS TO DESTABILIZE MUCH...AND PRESENT RADAR TRENDS SHOW A GENERAL
WEAKENING OF REFLECTIVITY WITHIN THE LINE. WEAK BOW ECHO ACROSS SWRN
PART OF WW 94...MOVING THROUGH HENRY AND JOHNSON COUNTIES IN
MO...HAS ALSO EXHIBITED WEAKENING. UPPER-LEVEL SUPPORT SHOULD
MAINTAIN LINE MOVEMENT ENEWD AT 25 KT...ALTHOUGH SEVERE THREAT
APPEARS TO BE MINIMAL. 

IN S-CENTRAL IA...ISOLATED SEVERE THUNDERSTORMS HAVE MOVED EAST OF
THE WATCH AREA. ANTICYCLONIC CURVATURE OF UPPER CIRRUS PLUME MOVING
INTO REGION SUGGESTS LIMITED POTENTIAL FOR ADDITIONAL DEVELOPMENT
DURING NEXT 1-2 HOURS. HOWEVER...CONVECTIVE COMPLEX WITH STRONG
MESOSCALE COLD POOL OVER NERN NEB MOVING SEWD WOULD IMPACT SWRN INTO
S-CENTRAL IA BETWEEN 2-3Z IF TRENDS PERSIST. THIS NERN NEB CLUSTER
MAY CONTINUE GIVEN MESOSCALE ORGANIZATION AND INSTABILITY AXIS INTO
S-CENTRAL IA /MUCAPE TO 1000 J/KG/.

..BANACOS.. 04/21/2004

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

ATTN...WFO...LSX...DVN...SGF...DMX...EAX...

38259467 41769431 41759143 38259194

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 8:06 PM CDTMesoscale DiscussionSPCFremont, Harrison, Mills, Monona, Montgomery, Page and 2 more84 min
Apr 21, 3:04 PM CDTMesoscale DiscussionSPCHarrison, Lyon, Monona, Plymouth, Sioux, Woodbury2 hr
Apr 20, 7:22 PM CDTMesoscale DiscussionSPCBarry, Barton, Cedar, Dade, Jasper, Lawrence and 4 more23 min
Apr 20, 7:50 PM CDTTornado WatchSPCBarry, McDonald, Stone, Taney5 hr
Apr 20, 8:57 PM CDTMesoscale DiscussionSPCBarry, McDonald, Stone, Taney2 hr
Apr 20, 9:38 PM CDTMesoscale DiscussionSPCAudrain, Boone, Callaway, Cole, Crawford, Dent and 16 more37 min
Apr 20, 10:57 PM CDTMesoscale DiscussionSPCBarry, McDonald, Stone, Taney93 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

Nearby

Mesoscale Discussions in Missouri, 2004Mesoscale Discussions in Iowa, 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.