Alert archive / Iowa / Mesoscale Discussions in 2005

Mesoscale Discussion 1849

July 24, 200542 counties in Iowa; 37 counties in Nebraska; Clay County, Union County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 24, 2005, 4:10 PM CDT for 42 counties in Iowa; 37 counties in Nebraska; Clay County, Union County, South Dakota. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Jul 24, 2005, 4:10 PM CDT (21:10 UTC)
Expired
Jul 24, 2005, 5:45 PM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 81 counties

Audubon County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Buena Vista County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cerro Gordo County, IA, Cherokee County, IA, Chickasaw County, IA, Clay County, IA, Crawford County, IA, Delaware County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Ida County, IA, Kossuth County, IA, Marshall County, IA, Monona County, IA, O'Brien County, IA, Palo Alto County, IA, Plymouth County, IA, Pocahontas County, IA, Sac County, IA, Shelby County, IA, Sioux County, IA, Story County, IA, Webster County, IA, Winneshiek County, IA, Woodbury County, IA, Wright County, IA, Antelope County, NE, Blaine County, NE, Boone County, NE, Brown County, NE, Buffalo County, NE, Burt County, NE, Butler County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Custer County, NE, Dakota County, NE, Dixon County, NE, Dodge County, NE, Garfield County, NE, Greeley County, NE, Hall County, NE, Hamilton County, NE, Holt County, NE, Howard County, NE, Knox County, NE, Loup County, NE, Madison County, NE, Merrick County, NE, Nance County, NE, Pierce County, NE, Platte County, NE, Polk County, NE, Rock County, NE, Saunders County, NE, Sherman County, NE, Stanton County, NE, Thurston County, NE, Valley County, NE, Washington County, NE, Wayne County, NE, Wheeler County, NE, Clay County, SD, Union County, SD

The radar

The Omaha radar (KOAX), 103 km from the middle of the area, began a volume at 21:12 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 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, 9.2 hours before the alert went out and 103 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 2005-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 699 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 12:00Z on 2005-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -42 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
699 J/kg
Mixed-layer CIN
-380 J/kg
Mixed-layer LCL
1888 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-42 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 242110
SWOMCD
SPC MCD 242110 
IAZ000-NEZ000-SDZ000-242245-

MESOSCALE DISCUSSION 1849
NWS STORM PREDICTION CENTER NORMAN OK
0410 PM CDT SUN JUL 24 2005

AREAS AFFECTED...CENTRAL NEBRASKA INTO NRN AND CENTRAL IA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 242110Z - 242245Z

STORMS MAY DEVELOP OVER THE NEXT 1-3 HOURS. A WW COULD BE REQUIRED
FOR HAIL AND WIND.

SURFACE ANALYSIS SHOWS WEAK SURFACE PRESSURE TROUGH EXTENDING FROM
WI ACROSS IA AND NEBRASKA...COINCIDENT WITH LOW LEVEL DEFORMATION
ZONE. THE AIR MASS HAS BECOME STRONGLY UNSTABLE THIS AFTERNOON AND
CONTINUED HEATING WILL OCCUR. MODIFIED FORECAST SOUNDINGS INDICATE
CONVECTIVE INHIBITION HAS ERODED OVER MUCH OF THE AREA...AND LOW
LEVEL CONVERGENCE IS FORECAST TO INCREASE DUE TO INCREASING SLY LOW
LEVEL JET...ESPECIALLY OVER ERN NEBRASKA. THUS...AT LEAST ISOLATED
SEVERE DEVELOPMENT IS ANTICIPATED BY LATE AFTERNOON.

ALTHOUGH MID TO UPPER LEVEL WIND PROFILES WILL REMAIN
WEAK...INCREASING LOW LEVEL JET WILL ALLOW HELICITY TO
INCREASE...WITH WIND PROFILES/HODOGRAPHS SUPPORTING VERY SLOW MOVING
SUPERCELLS BY EARLY EVENING...ESPECIALLY OVER NEBRASKA.

..JEWELL.. 07/24/2005

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

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

43229540 43299346 43379229 43329158 42259111 41979338
41319623 40589853 40629911 41360030 41920048 42180027
42699955

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 24, 10:33 AM CDTMesoscale DiscussionSPCBremer, Buena Vista, Butler, Cerro Gordo, Cherokee, Chickasaw and 23 more117 min
Jul 24, 4:50 PM CDTSevere Thunderstorm WatchSPCBoone, Buena Vista, Butler, Calhoun, Carroll, Cerro Gordo and 31 more5 hr
Jul 24, 6:26 PM CDTMesoscale DiscussionSPCAllamakee, Black Hawk, Bremer, Buchanan, Chickasaw, Clayton and 5 more64 min
Jul 24, 3:30 AM CDTSevere Thunderstorm WatchSPCBoyd2 hr
Jul 24, 5:22 AM CDTMesoscale DiscussionSPCBoyd83 min
Jul 24, 3:14 AM CDTMesoscale DiscussionSPCAurora, Brule, Davison, Gregory, Jerauld, Kingsbury and 3 more91 min
Jul 24, 2:14 PM CDTMesoscale DiscussionSPCButte, Corson, Dewey, Haakon, Harding, Lawrence and 4 more2 hr
Jul 24, 2:50 PM CDTSevere Thunderstorm WatchSPCButte, Harding, Lawrence, Meade, Perkins7 hr

Nearby

Mesoscale Discussions in Iowa, 2005Mesoscale Discussions in Nebraska, 2005Mesoscale Discussions in South Dakota, 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.