Alert archive / Iowa / Mesoscale Discussions in 2021
Mesoscale Discussion 1003
The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2021, 9:27 PM CDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 18, 2021, 9:27 PM CDT (02:27 UTC)
- Expired
- Jun 18, 2021, 11:30 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 67 counties
Adair County, IA, Adams County, IA, Appanoose County, IA, Cass County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Fremont County, IA, Henry County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Mills County, IA, Monroe County, IA, Montgomery County, IA, Muscatine County, IA, Page County, IA, Polk County, IA, Pottawattamie County, IA, Poweshiek County, IA, Ringgold County, IA, Taylor County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Adams County, IL, Brown County, IL, Hancock County, IL, Henderson County, IL, McDonough County, IL, Mercer County, IL, Schuyler County, IL, Warren County, IL, Adair County, MO, Atchison County, MO, Clark County, MO, Gentry County, MO, Harrison County, MO, Knox County, MO, Lewis County, MO, Mercer County, MO, Nodaway County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO, Worth County, MO, Cass County, NE, Gage County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Saline County, NE, Sarpy County, NE
The radar
The Des Moines radar (KDMX), 129 km from the middle of the area, began a volume at 02:28 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
Davenport, (KDVN), launched 00:00Z, 2.5 hours before the alert went out and 222 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
- 4 J/kg
- Mixed-layer CIN
- -335 J/kg
- Mixed-layer LCL
- 2572 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- -15 m²/s²
- 0-3 km storm-relative helicity
- 55 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
441
ACUS11 KWNS 190227
SWOMCD
SPC MCD 190227
ILZ000-IAZ000-MOZ000-NEZ000-190430-
Mesoscale Discussion 1003
NWS Storm Prediction Center Norman OK
0927 PM CDT Fri Jun 18 2021
Areas affected...southeast NE...southern IA...northern
MO...west-central IL
Concerning...Severe potential...Watch likely
Valid 190227Z - 190430Z
Probability of Watch Issuance...80 percent
SUMMARY...Thunderstorms are expected to increase in coverage and
intensity this evening and overnight with the potential for very
large hail, damaging winds, and perhaps a tornado or two. A watch
will likely be needed by 0330z for parts of the discussion area for
this scenario.
DISCUSSION...A small cluster of strong/severe thunderstorms has
developed over southeast NE the vicinity of an east-west stationary
front. Increasing large-scale ascent, owing to warm advection
with a developing low-level jet and a subtle mid-level impulse
approaching from central NE, should help focus additional
thunderstorm development near the front over southern IA/northern MO
during the next few hours. The environment is supportive of
supercells with 40-45 kts of effective shear and MUCAPE in excess of
2500 J/kg. Storms will be capable of very large hail and damaging
downburst winds. Some tornado risk will also exist due to the
proximity of the front, where effective SRH values are in excess of
200 m2/s2. Storm mode should evolve into linear/bowing segments
with time with damaging wind potential becoming more prominent.
A watch will likely be needed for parts of the discussion area by
0330z.
..Bunting/Guyer.. 06/19/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ILX...LSX...DVN...DMX...EAX...OAX...
LAT...LON 39899069 40079280 40149399 40169710 40559721 41319587
41689409 41789270 41679130 41319067 40959031 40429022
39899069SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 18, 8:53 PM CDT | Mesoscale Discussion | SPC | Bond, Brown, Cass, Christian, Clark, Clay and 26 more | 97 min |
| Jun 18, 9:20 PM CDT | Severe Thunderstorm Watch | SPC | Cass, Champaign, Christian, Clark, Clay, Coles and 33 more | 7 hr |
| Jun 18, 10:08 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Bureau, Hancock, Henderson, Henry and 6 more | 8 hr |
| Jun 19, 2:10 AM CDT | Mesoscale Discussion | SPC | Adams, Brown, Cass, Champaign, Christian, Clark and 27 more | 2 hr |
| Jun 19, 11:15 AM CDT | Mesoscale Discussion | SPC | Effingham, Fayette, Greene, Macoupin, Montgomery, Morgan and 1 more | 2 hr |
| Jun 19, 2:12 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clinton, Greene, Jersey, Macoupin and 7 more | 93 min |
| Jun 19, 2:43 PM CDT | Severe Thunderstorm Watch | SPC | Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 9 more | 7 hr |
| Jun 19, 5:11 PM CDT | Mesoscale Discussion | SPC | Calhoun, Clinton, Greene, Jersey, Macoupin, Madison and 6 more | 64 min |
| Jun 19, 1:46 PM CDT | Mesoscale Discussion | SPC | Banner, Box Butte, Cheyenne, Deuel, Garden, Kimball and 2 more | 89 min |
| Jun 19, 2:44 PM CDT | Severe Thunderstorm Watch | SPC | Banner, Cheyenne, Deuel, Garden, Kimball, Morrill and 1 more | 7 hr |
| Jun 19, 4:24 PM CDT | Mesoscale Discussion | SPC | Cheyenne, Deuel, Morrill | 2 hr |
| Jun 19, 4:58 PM CDT | Mesoscale Discussion | SPC | Dawes | 92 min |
| Jun 19, 5:00 PM CDT | Mesoscale Discussion | SPC | Chase, Cheyenne, Dawson, Deuel, Dundy, Frontier and 10 more | 90 min |
| Jun 19, 5:48 PM CDT | Severe Thunderstorm Watch | SPC | Chase, Dawson, Dundy, Frontier, Furnas, Gosper and 8 more | 6 hr |
Nearby
Mesoscale Discussions in Iowa, 2021Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Illinois, 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.