Alert archive / Iowa / Mesoscale Discussions in 2005

Mesoscale Discussion 813

May 10, 200541 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at May 10, 2005, 11:35 PM CDT for 41 counties in Iowa. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
May 10, 2005, 11:35 PM CDT (04:35 UTC)
Expired
May 11, 2005, 1:00 AM CDT
In force
85 min
Issued by
the Storm Prediction Center
All 41 counties

Adair County, IA, Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cedar County, IA, Crawford County, IA, Dallas County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Iowa County, IA, Jasper County, IA, Johnson County, IA, Keokuk County, IA, Linn County, IA, Louisa County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Muscatine County, IA, Polk County, IA, Poweshiek County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Warren County, IA, Washington County, IA, Webster County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 12 km from the middle of the area, began a volume at 04:36 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, 4.6 hours before the alert went out and 230 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 2005-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2604 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 2005-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.193958Sfc1 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
2604 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
1952 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
124 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.2

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 110435
SWOMCD
SPC MCD 110435 
ILZ000-IAZ000-110600-

MESOSCALE DISCUSSION 0813
NWS STORM PREDICTION CENTER NORMAN OK
1135 PM CDT TUE MAY 10 2005

AREAS AFFECTED...ERN NEB...CNTRL/SRN IA

CONCERNING...TORNADO WATCH 243...

VALID 110435Z - 110600Z

CONTINUE REMAINING VALID PORTION OF WW.  NEW SEVERE WW MAY BE ISSUED
ACROSS IOWA BEFORE 06Z.

MUCH OF CONVECTIVE ACTIVITY NOW APPEARS TO BE DEVELOPING JUST TO
COOL SIDE OF SURFACE FRONT...NEAR/EAST OF WAVE/MESO LOW WHICH
REMAINS EVIDENT IN SURFACE DATA MIGRATING ACROSS THE OMAHA AREA INTO
SOUTHWEST IOWA.  SEVERAL GUSTS IN EXCESS OF 40 KT HAVE BEEN MEASURED
NEAR CONVECTIVE CLUSTER ASSOCIATED WITH THIS FEATURE...WHICH MAY
CONTINUE ACROSS THE DES MOINES AREA BY THE 06-07Z TIME FRAME.  

DOWNSTREAM CLUSTER OF STORMS...NOW APPROACHING DES MOINES...IS ALSO
SHOWING INCREASING SIGNS OF DAMAGING WIND THREAT EASTWARD ALONG THE
INTERSTATE 80 CORRIDOR NEXT COUPLE OF HOURS.  

FAVORABLE LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION/SHEAR AND
INSTABILITY ALONG FRONTAL ZONE FAVOR CONTINUATION OF HAIL/DAMAGING
WIND THREAT THROUGH MUCH OF THE NIGHT.

..KERR.. 05/11/2005

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

ATTN...WFO...DVN...ARX...DMX...FSD...OAX...

41799583 42649534 42819324 42769163 41439074 41019170
41169362 41149531

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 10, 7:30 PM CDTMesoscale DiscussionSPCBenton, Black Hawk, Boone, Bremer, Buchanan, Butler and 26 more2 hr
May 10, 9:14 PM CDTMesoscale DiscussionSPCAudubon, Black Hawk, Boone, Bremer, Buena Vista, Butler and 33 more2 hr
May 10, 9:54 PM CDTMesoscale DiscussionSPCAllamakee, Cerro Gordo, Chickasaw, Clay, Clayton, Dickinson and 15 more2 hr
May 11, 3:11 AM CDTMesoscale DiscussionSPCCedar, Clinton, Johnson, Louisa, Muscatine, Scott and 1 more2 hr
May 11, 8:41 AM CDTMesoscale DiscussionSPCAppanoose, Davis, Henry, Jefferson, Lee, Van Buren and 1 more2 hr

Nearby

Mesoscale Discussions in Iowa, 2005Every mesoscale discussion in 2005

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.