Alert archive / Iowa / Mesoscale Discussions in 2004
Mesoscale Discussion 792
The Storm Prediction Center issued this mesoscale discussion at May 21, 2004, 6:23 AM CDT for 26 counties in Iowa; 26 counties in Minnesota. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- May 21, 2004, 6:23 AM CDT (11:23 UTC)
- Expired
- May 21, 2004, 7:30 AM CDT
- In force
- 67 min
- Issued by
- the Storm Prediction Center
All 52 counties
Allamakee County, IA, Bremer County, IA, Butler County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clay County, IA, Clayton County, IA, Dickinson County, IA, Emmet County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Hancock County, IA, Howard County, IA, Humboldt County, IA, Kossuth County, IA, Lyon County, IA, Mitchell County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Sioux County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Blue Earth County, MN, Brown County, MN, Cottonwood County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Jackson County, MN, Le Sueur County, MN, Martin County, MN, Mower County, MN, Murray County, MN, Nicollet County, MN, Nobles County, MN, Olmsted County, MN, Pipestone County, MN, Redwood County, MN, Rice County, MN, Rock County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN
The radar
The Minneapolis radar (KMPX), 157 km from the middle of the area, began a volume at 11:26 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
Minneapolis, MN (KMPX), launched 00:00Z, 11.4 hours before the alert went out and 157 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1738 m above ground
- 0-6 km bulk shear
- 62 kt
- 0-1 km storm-relative helicity
- -46 m²/s²
- 0-3 km storm-relative helicity
- 121 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
511 ACUS11 KWNS 211123 SWOMCD SPC MCD 211123 WIZ000-IAZ000-MNZ000-SDZ000-211230- MESOSCALE DISCUSSION 0792 NWS STORM PREDICTION CENTER NORMAN OK 0623 AM CDT FRI MAY 21 2004 AREAS AFFECTED...SRN MN/NRN IA CONCERNING...SEVERE THUNDERSTORM WATCH 228...229...230... VALID 211123Z - 211230Z WW/S 228/229/230 WILL BE ALLOWED TO EXPIRE AS SCHEDULED AT 12Z. WIND PROFILER/VAD DATA SHOW THE STRONG NOCTURNAL LLJ HAS CONTINUED TO VEER AND IS NOW ORIENTED WSWLY ACROSS CENTRAL IA/NWRN MO. SURFACE ANALYSIS AT 11Z SHOWED A LOW OVER ERN NEB...20 SW OLU...WITH THE WARM FRONT CONTINUING TO SLOWLY MOVE NWD ACROSS CENTRAL IA. THE LLJ WILL FOCUS THE STRONGEST ISENTROPIC ASCENT ATOP A SHALLOW BOUNDARY LAYER...PER RUC POINT FORECAST SOUNDINGS...ACROSS FAR NERN IA AND SWRN WI DURING THE NEXT 2-3 HOURS. MUCAPE VALUES OF 2000-3000 J/KG AND STRONG CAPE BEARING SHEAR WILL CONTINUE TO SUPPORT ELEVATED SUPERCELLS WITH HAIL AS THE PRIMARY THREAT. REGIONAL RADARS SHOW THE STRONGEST STORM IS LOCATED IN FAYETTE COUNTY IA...AND SHOULD EXIT THE ERN PORTION OF WW 230 BY 12Z. ALTHOUGH A FEW STRONG STORMS WILL BE POSSIBLE ACROSS PORTIONS OF THE REST OF NRN IA INTO SRN MN...RADAR TRENDS SHOW AN OVERALL DECREASE IN STORM INTENSITIES. THUS...THESE WW/S WILL BE ALLOWED TO EXPIRE AT 12Z. ..PETERS.. 05/21/2004 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DVN...ARX...MPX...DMX...FSD... 42499114 42589376 43129652 43559652 44229638 44409597 44599200 43629114
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 7:32 PM CDT | Mesoscale Discussion | SPC | Cedar, Clinton, Des Moines, Henry, Jefferson, Keokuk and 5 more | 88 min |
| May 20, 10:03 PM CDT | Mesoscale Discussion | SPC | Fremont, Harrison, Mills, Pottawattamie | 87 min |
| May 21, 1:11 AM CDT | Mesoscale Discussion | SPC | Audubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 27 more | 34 min |
| May 21, 1:20 AM CDT | Severe Thunderstorm Watch | SPC | Audubon, Boone, Buena Vista, Calhoun, Carroll, Cherokee and 19 more | 6 hr |
| May 21, 2:22 AM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 47 more | 23 min |
| May 21, 2:35 AM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 22 more | 4 hr |
| May 21, 4:34 AM CDT | Mesoscale Discussion | SPC | Allamakee, Black Hawk, Bremer, Buchanan, Buena Vista, Butler and 35 more | 56 min |
| May 21, 9:44 AM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Buena Vista and 38 more | 3 hr |
| May 21, 10:25 AM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 37 more | 6 hr |
| May 21, 1:59 PM CDT | Mesoscale Discussion | SPC | Benton, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 9 more | 2 hr |
| May 21, 2:45 PM CDT | Tornado Watch | SPC | Allamakee, Audubon, Benton, Black Hawk, Boone, Bremer and 59 more | 7 hr |
| May 21, 6:33 PM CDT | Mesoscale Discussion | SPC | Lyon, Plymouth, Sioux, Woodbury | 57 min |
| May 21, 2:20 AM CDT | Severe Thunderstorm Watch | SPC | Blue Earth, Brown, Cottonwood, Dodge, Faribault, Fillmore and 20 more | 5 hr |
Nearby
Mesoscale Discussions in Iowa, 2004Mesoscale Discussions in Minnesota, 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.