Alert archive / Iowa / Mesoscale Discussions in 2004

Mesoscale Discussion 2213

September 15, 200443 counties in Iowa; Atchison County, Nodaway County, Worth County, Missouri; 4 counties in Nebraska

The Storm Prediction Center issued this mesoscale discussion at Sep 15, 2004, 4:00 AM CDT for 43 counties in Iowa; Atchison County, Nodaway County, Worth County, Missouri; 4 counties in Nebraska. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Sep 15, 2004, 4:00 AM CDT (09:00 UTC)
Expired
Sep 15, 2004, 6:30 AM CDT
In force
3 hr
Issued by
the Storm Prediction Center
All 50 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Buchanan County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Decatur County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Harrison County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Mills County, IA, Monroe County, IA, Montgomery County, IA, Page County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Atchison County, MO, Nodaway County, MO, Worth County, MO, Cass County, NE, Johnson County, NE, Nemaha County, NE, Otoe County, NE

The radar

The Des Moines radar (KDMX), 99 km from the middle of the area, began a volume at 09:00 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, 9.0 hours before the alert went out and 146 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 2004-09-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1520 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 2004-09-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 183 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
1520 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
1898 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
183 m²/s²
0-3 km storm-relative helicity
290 m²/s²
Significant tornado parameter
0.2
Supercell composite
8.2

Open this sounding in Storm Lab

The text

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

111 
ACUS11 KWNS 150903
SWOMCD
SPC MCD 150900 
IAZ000-MOZ000-NEZ000-151130-

MESOSCALE DISCUSSION 2213
NWS STORM PREDICTION CENTER NORMAN OK
0400 AM CDT WED SEP 15 2004

AREAS AFFECTED...ERN NEB INTO SWRN IA AND NRN MO

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 150900Z - 151130Z

NEARLY SOLID LINE OF DEEP CONVECTION WILL CONTINUE MOVING EAST AT
40KT ACROSS THE MO RIVER EARLY TODAY. 40-50KT WINDS MAY ACCOMPANY
THE PASSAGE OF THE SQUALL LINE. TIME OF DAY AND BORDERLINE NATURE OF
THE SEVERE WIND THREAT SUGGESTS A WATCH IS UNNECESSARY DESPITE
STRONG FORCING TO MAINTAIN TSTMS ACROSS THE REGION.

POTENT UPPER TROUGH WITH 50-60KT MID LEVEL FLOW WAS SPREADING EAST
ACROSS THE CNTRL PLAINS EARLY TODAY. ASSOCIATED SURFACE LOW OVER
NWRN IA WILL CONTINUE TO DEEPEN WHILE TRACKING INTO SWRN MN. AS THIS
OCCURS...TRAILING COLD FRONT/SQUALL LINE WILL SWEEP EWD/SEWD INTO
INSTABILITY AXIS ACROSS ERN NEB AND SWRN IA. STRONG DYNAMIC FORCING
ASSOCIATED WITH THE DEEPENING LOW...IN ADDITION TO MATURE CONVECTIVE
COLD POOL BEHIND THE SQUALL LINE...SHOULD MAINTAIN DEEP CONVECTION
ALONG THE ADVANCING FRONT. UPDRAFTS ASSOCIATED WITH STORM SCALE
BOUNDARY INTERSECTIONS ALONG THE LINE HAVE RESULTED IN OCCASIONAL
GUSTS TO AROUND 50KT ACROSS SRN NEB OVER THE PAST COUPLE OF HOURS.
EXPECT THIS POTENTIAL TO PERSIST ALONG SMALL SEGMENTS THE LINE AS IT
MOVES EAST INTO IA. HOWEVER...IT APPEARS MOST TSTM GUSTS SHOULD
REMAIN IN THE 40-50KT RANGE AND A WATCH MAY NOT BE NEEDED UNLESS A
MORE WIDESPREAD/HIGHER WIND THREAT DEVELOPS.

..CARBIN.. 09/15/2004

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

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

40289452 40119677 41039613 42079573 42389488 42549179
40599272

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 14, 7:17 PM CDTMesoscale DiscussionSPCAdair, Audubon, Boone, Buena Vista, Calhoun, Carroll and 32 more118 min
Sep 14, 8:16 PM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Howard, Mitchell, Winneshiek3 hr
Sep 15, 12:25 PM CDTTornado WatchSPCAllamakee, Bremer, Butler, Chickasaw, Clayton, Fayette and 4 more8 hr
Sep 15, 2:34 PM CDTMesoscale DiscussionSPCBarton, Bates, Benton, Boone, Camden, Carroll and 30 more86 min
Sep 14, 7:35 PM CDTSevere Thunderstorm WatchSPCAdams, Antelope, Blaine, Boone, Buffalo, Clay and 37 more6 hr
Sep 14, 9:25 PM CDTSevere Thunderstorm WatchSPCDundy, Furnas, Hitchcock, Red Willow5 hr

Nearby

Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Nebraska, 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.