Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 839

May 23, 200420 counties in Iowa; 5 counties in Kansas; 17 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 23, 2004, 2:21 AM CDT for 20 counties in Iowa; 5 counties in Kansas; 17 counties in Missouri. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
May 23, 2004, 2:21 AM CDT (07:21 UTC)
Expired
May 23, 2004, 3:15 AM CDT
In force
54 min
Issued by
the Storm Prediction Center
All 42 counties

Appanoose County, IA, Buchanan County, IA, Cedar County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Wayne County, IA, Atchison County, KS, Brown County, KS, Doniphan County, KS, Jackson County, KS, Pottawatomie County, KS, Adair County, MO, Andrew County, MO, Buchanan County, MO, Caldwell County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Holt County, MO, Linn County, MO, Livingston County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The radar

The Des Moines radar (KDMX), 113 km from the middle of the area, began a volume at 07:20 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

Omaha, NE (KOAX), launched 00:00Z, 7.4 hours before the alert went out and 299 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, Omaha, NE at 00:00Z on 2004-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2882 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, Omaha, NE at 00:00Z on 2004-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 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
2882 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
1091 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
4.2
Supercell composite
16.7

Open this sounding in Storm Lab

The text

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

904 
ACUS11 KWNS 230721
SWOMCD
SPC MCD 230721 
ILZ000-IAZ000-MOZ000-KSZ000-NEZ000-230815-

MESOSCALE DISCUSSION 0839
NWS STORM PREDICTION CENTER NORMAN OK
0221 AM CDT SUN MAY 23 2004

AREAS AFFECTED...NERN KS/NWRN MO/SRN-ERN IA

CONCERNING...HEAVY RAINFALL...TORNADO WATCH 256...

VALID 230721Z - 230815Z

WW 256 WILL BE ALLOWED TO EXPIRE AT 07Z.

SEVERE BOW ECHOES...ONE ACROSS ERN IA AND THE SECOND OVER NRN MO/SRN
IA...WILL CONTINUE TO MOVE EWD AT 45-50 KT PRODUCING DAMAGING WINDS.
 THESE BOWS WILL EXIT WW 256 BY/JUST AFTER 07Z...THUS ALLOWING THIS
WW TO EXPIRE AS SCHEDULED.

A HEAVY RAINFALL THREAT IS DEVELOPING ACROSS NWRN-NRN MO AS TRAILING
EDGE OF BOW ECHO OVER NORTH CENTRAL MO/SOUTH CENTRAL IA CONTINUES TO
BECOME ORIENTED E-W...WITH ADDITIONAL STORMS DEVELOPING ACROSS FAR
NERN KS ON THE SWRN FLANK OF THIS ACTIVITY.  PRECIPITABLE WATER
VALUES RANGING AROUND 1.5 INCHES ACROSS THIS AREA AND 5-10 KT W-E
ORIENTED CORFIDI VECTORS SUPPORT RAINFALL RATES AROUND 1 IN/HR. 
STORMS WILL CONTINUE TO TRAIN EWD ACROSS NWRN INTO NRN MO DURING THE
NEXT SEVERAL HOURS.

..PETERS.. 05/23/2004

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

ATTN...WFO...LSX...DVN...ARX...DMX...EAX...OAX...TOP...

41049100 39979239 38969671 40099575 40389365 41349299
41659192 42519184 42689106

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 22, 7:11 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Clarke, Dallas and 15 more94 min
May 22, 7:23 PM CDTMesoscale DiscussionSPCAdair, Adams, Audubon, Cass, Dallas, Fremont and 9 more67 min
May 22, 8:58 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Benton, Boone and 49 more92 min
May 22, 10:40 PM CDTTornado WatchSPCAdair, Adams, Appanoose, Benton, Cedar, Clarke and 33 more5 hr
May 22, 11:33 PM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Benton, Cedar, Clarke and 33 more87 min
May 23, 12:24 AM CDTMesoscale DiscussionSPCCedar, Clinton, Des Moines, Dubuque, Jackson, Jones and 3 more66 min
May 23, 12:40 AM CDTSevere Thunderstorm WatchSPCClinton, Dubuque, Jackson, Scott5 hr
May 23, 4:30 AM CDTMesoscale DiscussionSPCClinton, Des Moines, Jackson, Lee, Louisa, Muscatine and 1 more60 min
May 23, 12:25 PM CDTMesoscale DiscussionSPCCedar, Clinton, Delaware, Des Moines, Dubuque, Henry and 7 more95 min
May 23, 1:15 PM CDTTornado WatchSPCDes Moines, Lee6 hr
May 23, 2:05 PM CDTTornado WatchSPCAllamakee, Benton, Buchanan, Cedar, Clayton, Clinton and 14 more8 hr
May 23, 5:10 PM CDTMesoscale DiscussionSPCClinton, Dubuque, Jackson, Scott95 min
May 22, 7:49 PM CDTMesoscale DiscussionSPCBarton, Clay, Cloud, Dickinson, Ellsworth, Geary and 14 more86 min
May 22, 10:09 PM CDTMesoscale DiscussionSPCBarton, Clay, Cloud, Dickinson, Ellsworth, Geary and 13 more66 min
May 23, 1:21 AM CDTMesoscale DiscussionSPCAtchison, Brown, Dickinson, Doniphan, Douglas, Geary and 13 more24 min
May 23, 1:40 AM CDTSevere Thunderstorm WatchSPCAdair, Buchanan, Caldwell, Clark, Clinton, Daviess and 11 more4 hr
May 23, 4:35 PM CDTSevere Thunderstorm WatchSPCBarry, Camden, Christian, Crawford, Dade, Dallas and 24 more5 hr
May 23, 5:00 PM CDTMesoscale DiscussionSPCCallaway, Cole, Crawford, Franklin, Gasconade, Jefferson and 15 more2 hr
May 23, 5:30 PM CDTTornado WatchSPCJefferson, Saint Charles, Saint Louis, City of Saint Louis6 hr

Nearby

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