Alert archive / Iowa / Mesoscale Discussions in 2003

Mesoscale Discussion 736

May 4, 200328 counties in Iowa; 12 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at May 4, 2003, 3:56 PM CDT for 28 counties in Iowa; 12 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 4, 2003, 3:56 PM CDT (20:56 UTC)
Expired
May 4, 2003, 6:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 40 counties

Adair County, IA, Appanoose County, IA, Audubon County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Greene County, IA, Guthrie County, IA, Harrison County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Monona County, IA, Monroe County, IA, Polk County, IA, Shelby County, IA, Story County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Adair County, MO, Chariton County, MO, Grundy County, MO, Harrison County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 8.9 hours before the alert went out and 184 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 12:00Z on 2003-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2003-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 375 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
558 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
375 m²/s²
0-3 km storm-relative helicity
509 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.

126 
ACUS11 KWNS 042057
SWOMCD
SPC MCD 042056 
IAZ000-MOZ000-042300-

MESOSCALE DISCUSSION 0736
NWS STORM PREDICTION CENTER NORMAN OK
0356 PM CDT SUN MAY 04 2003

AREAS AFFECTED...CNTRL/SRN IA...N CNTRL MO

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 042056Z - 042300Z

SEVERE THREAT WILL INCREASE NORTHEAST OF TORNADO WATCH 233 BY EARLY
EVENING. NEW WW MAY BE NEEDED ACROSS PARTS OF CENTRAL IOWA/NORTH
CENTRAL MISSOURI WITHIN THE NEXT HOUR OR TWO.

MODELS SUGGEST STRONGEST UPPER DIFLUENCE/DIVERGENCE CURRENTLY
CENTERED OVER EASTERN NEBRASKA WILL CONTINUE TO SPREAD NORTHEASTWARD
LATE THIS AFTERNOON...BECOMING FOCUSED OVER SOUTHWEST IOWA BY
05/00Z.  THIS WILL CONTINUE TO ENHANCE CONVECTIVE DEVELOPMENT...
MOST INTENSE OF WHICH NOW IS CURRENTLY APPROACHING THE OMAHA AREA...
NEAR DEEPENING SURFACE CYCLONE.  THREAT FOR TORNADIC SUPERCELLS WILL
CONTINUE ANOTHER FEW HOURS NEAR THE MISSOURI RIVER...BUT A GRADUAL
EVOLUTION OF LARGER MESOSCALE CONVECTIVE SYSTEM/SQUALL LINE IS
LIKELY ALONG LEADING EDGE OF MID-LEVEL COOLING...WHICH WILL SPREAD
INTO PARTS OF CENTRAL IOWA/MISSOURI BY EARLY EVENING.

..KERR.. 05/04/2003

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

ATTN...WFO...LSX...DVN...DMX...EAX...FSD...OAX...

42139618 42339535 42159342 41519224 40459203 39649251
39059307 39909389 41109432 41369526 41479582

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 11:46 PM CDTMesoscale DiscussionSPCAdams, Cass, Fremont, Harrison, Mills, Monona and 5 more59 min
May 4, 12:10 AM CDTSevere Thunderstorm WatchSPCAdair, Adams, Audubon, Boone, Carroll, Cass and 18 more6 hr
May 4, 2:58 AM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Audubon, Boone, Carroll and 37 more92 min
May 4, 4:50 AM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Cass, Clarke, Davis and 23 more6 hr
May 4, 7:43 AM CDTMesoscale DiscussionSPCAdair, Adams, Appanoose, Cass, Clarke, Davis and 15 more2 hr
May 4, 9:48 AM CDTMesoscale DiscussionSPCAudubon, Buena Vista, Carroll, Cass, Cherokee, Clay and 17 more117 min
May 4, 12:14 PM CDTMesoscale DiscussionSPCFremont, Mills, Montgomery, Page, Pottawattamie, Taylor2 hr
May 4, 12:45 PM CDTTornado WatchSPCAdams, Cass, Fremont, Mills, Montgomery, Page and 2 more6 hr
May 4, 2:22 PM CDTMesoscale DiscussionSPCFremont, Mills, Montgomery, Page, Pottawattamie, Taylor113 min
May 4, 5:25 PM CDTSevere Thunderstorm WatchSPCAppanoose, Davis, Des Moines, Lee, Van Buren6 hr
May 4, 5:50 PM CDTSevere Thunderstorm WatchSPCAdair, Adams, Appanoose, Clarke, Dallas, Decatur and 14 more5 hr
May 4, 12:35 PM CDTTornado WatchSPCBarry, Barton, Cedar, Dade, Jasper, Lawrence and 4 more6 hr
May 4, 3:05 PM CDTMesoscale DiscussionSPCBarton, Jasper, McDonald, Newton115 min
May 4, 4:28 PM CDTMesoscale DiscussionSPCBuchanan, Caldwell, Clay, Clinton, DeKalb, Jackson and 3 more62 min
May 4, 4:43 PM CDTMesoscale DiscussionSPCBarton, Bates, Cedar, Dade, Jasper, Newton and 2 more2 hr
May 4, 5:01 PM CDTMesoscale DiscussionSPCButler, Dunklin, Mississippi, New Madrid, Pemiscot, Stoddard3 hr
May 4, 5:20 PM CDTMesoscale DiscussionSPCBarry, Barton, Cedar, Christian, Dade, Dallas and 18 more55 min
May 4, 6:05 PM CDTTornado WatchSPCBarry, Barton, Camden, Carter, Cedar, Christian and 30 more7 hr
May 4, 6:20 PM CDTTornado WatchSPCAndrew, Bates, Benton, Boone, Buchanan, Caldwell and 34 more6 hr
May 4, 6:55 PM CDTTornado WatchSPCButler, Dunklin, Mississippi, New Madrid, Pemiscot, Scott and 2 more6 hr

Nearby

Mesoscale Discussions in Iowa, 2003Mesoscale Discussions in Missouri, 2003Every mesoscale discussion in 2003

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.