Alert archive / Iowa / Mesoscale Discussions in 2021
Mesoscale Discussion 1288
The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2021, 5:47 PM CDT for 35 counties in Iowa. It was in force for 118 min.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2021, 5:47 PM CDT (22:47 UTC)
- Expired
- Jul 14, 2021, 7:45 PM CDT
- In force
- 118 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 378
All 35 counties
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, Cerro Gordo County, IA, Chickasaw County, IA, Crawford County, IA, Dallas County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Humboldt County, IA, Jasper County, IA, Marshall County, IA, Monona County, IA, Polk County, IA, Poweshiek County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Tama County, IA, Webster County, IA, Wright County, IA
The radar
The Des Moines radar (KDMX), 74 km from the middle of the area, began a volume at 22:50 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 12:00Z, 10.8 hours before the alert went out and 256 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
- 967 J/kg
- Mixed-layer CIN
- -125 J/kg
- Mixed-layer LCL
- 1201 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 35 m²/s²
- 0-3 km storm-relative helicity
- -7 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -0.1
The text
As transmitted.
287
ACUS11 KWNS 142247
SWOMCD
SPC MCD 142247
IAZ000-NEZ000-150045-
Mesoscale Discussion 1288
NWS Storm Prediction Center Norman OK
0547 PM CDT Wed Jul 14 2021
Areas affected...Central into northeast Iowa
Concerning...Tornado Watch 378...
Valid 142247Z - 150045Z
The severe weather threat for Tornado Watch 378 continues.
SUMMARY...The potential for tornadoes will be focused in northeast
Iowa and potential parts of east-central Iowa. Farther west, veered
surface flow will limit tornado potential, though damaging winds and
perhaps isolated hail remain a possibility.
DISCUSSION...The remaining area of greatest concern for a continued
tornado threat exists in northeastern Iowa. A confirmed tornado was
located in Bremer County east of Waverly. This storm has remained
discrete and will likely be the focus for tornadic potential over
the next hour or two. To its southwest, another cluster of
supercells has recently grown upscale. While the storm mode would
indicate a lower tornado threat, temperatures downstream of these
storms have continued to warm into the upper 70s to low 80s F.
Surface winds remain backed and will continue to support enhanced
low-level SRH and potential for tornadoes.
To the west of I-35, surface winds have veered considerably and are
now west to west-southwesterly. Though storms have developed along
the cold front, these storms are more of a damaging wind gusts and
perhaps isolated large hail threat. The tornado threat in these
areas is relatively lower.
..Wendt.. 07/14/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DVN...ARX...DMX...FSD...OAX...
LAT...LON 41989622 42649484 43239344 43339272 43249210 43049164
42629166 42139172 41559217 41489499 41499588 41989622SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 7:02 AM CDT | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Boone, Bremer, Buchanan and 43 more | 2 hr |
| Jul 14, 8:54 AM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 13 more | 5 hr |
| Jul 14, 11:45 AM CDT | Mesoscale Discussion | SPC | Allamakee, Clayton, Dubuque, Jackson, Jones | 2 hr |
| Jul 14, 1:40 PM CDT | Mesoscale Discussion | SPC | Audubon, Black Hawk, Boone, Bremer, Buena Vista, Butler and 38 more | 2 hr |
| Jul 14, 2:35 PM CDT | Tornado Watch | SPC | Audubon, Benton, Black Hawk, Boone, Bremer, Buchanan and 41 more | 8 hr |
| Jul 14, 4:17 PM CDT | Mesoscale Discussion | SPC | Boone, Butler, Calhoun, Franklin, Greene, Grundy and 5 more | 58 min |
| Jul 14, 5:42 PM CDT | Mesoscale Discussion | SPC | Allamakee, Clayton, Delaware, Dubuque, Jackson, Jones | 63 min |
| Jul 14, 6:13 PM CDT | Tornado Watch | SPC | Allamakee, Cedar, Clayton, Clinton, Delaware, Dubuque and 7 more | 6 hr |
Nearby
Mesoscale Discussions in Iowa, 2021Every mesoscale discussion in 2021
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.