Alert archive / Iowa / Mesoscale Discussions in 2017
Mesoscale Discussion 263
The Storm Prediction Center issued this mesoscale discussion at Mar 6, 2017, 7:42 PM CST for 18 counties in Illinois; 46 counties in Iowa. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Mar 6, 2017, 7:42 PM CST (01:42 UTC)
- Expired
- Mar 6, 2017, 8:45 PM CST
- In force
- 63 min
- Issued by
- the Storm Prediction Center
All 64 counties
Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Chickasaw County, IA, Clayton County, IA, Clinton County, IA, Davis County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Floyd County, IA, Grundy County, IA, Henry County, IA, Howard County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Muscatine County, IA, Polk County, IA, Poweshiek County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Winneshiek County, IA, Bureau County, IL, Carroll County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Knox County, IL, Lee County, IL, Marshall County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL
The radar
The Quad Cities radar (KDVN), 88 km from the middle of the area, began a volume at 01:42 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, 1.7 hours before the alert went out and 94 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
- 39 J/kg
- Mixed-layer CIN
- -343 J/kg
- Mixed-layer LCL
- 1016 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 407 m²/s²
- 0-3 km storm-relative helicity
- 489 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
483
ACUS11 KWNS 070143
SWOMCD
SPC MCD 070142
ILZ000-WIZ000-IAZ000-MOZ000-MNZ000-070245-
Mesoscale Discussion 0263
NWS Storm Prediction Center Norman OK
0742 PM CST Mon Mar 06 2017
Areas affected...eastern Iowa and northwestern Illinois
Concerning...Tornado Watch 61...
Valid 070142Z - 070245Z
The severe weather threat for Tornado Watch 61 continues.
SUMMARY...The severe threat continues across the remainder of WW 61.
This threat should eventually evolve eastward into downstream areas
of Illinois. A new watch will be coordinated within the next hour
or so.
DISCUSSION...A strong to severe squall line has emerged across
central Iowa. This line has been responsible for numerous reports
of hail and wind, along with occasional tornado reports. These
storms are in an environment characterized by weak to moderate
instability, but very strong low-level and deep layer shear, which
has support occasional rotation and bow/LEWP-type patterns within
the line.
This line should gradually shift east of WW 61 over the next one to
two hours, with an attendant severe wind/hail and tornado threat
continuing downstream into Illinois. A new severe weather watch
will be coordinated with affected offices within the next hour or
so.
..Cook/Guyer.. 03/07/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LOT...ILX...MKX...DVN...ARX...DMX...EAX...
LAT...LON 43509242 43509179 43439127 43259114 42999104 42739081
42589052 42519017 42498956 42508917 42198896 41558893
40918919 40608989 40559081 40559173 40589243 40649255
40659313 40659344 40699361 40969373 41279375 41679361
42499316 43159275 43509242SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 6, 8:10 PM CST | Mesoscale Discussion | SPC | Alexander | 3 hr |
| Mar 6, 8:22 PM CST | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 24 more | 2 hr |
| Mar 6, 8:52 PM CST | Tornado Watch | SPC | Adams, Bond, Brown, Bureau, Calhoun, Carroll and 38 more | 6 hr |
| Mar 6, 10:15 PM CST | Mesoscale Discussion | SPC | Boone, DeKalb, DeWitt, Ford, Grundy, Kane and 11 more | 60 min |
| Mar 6, 10:35 PM CST | Severe Thunderstorm Watch | SPC | Boone, Champaign, Christian, Coles, Cook, DeKalb and 25 more | 4 hr |
| Mar 6, 11:13 PM CST | Mesoscale Discussion | SPC | Alexander, Bond, Calhoun, Clay, Clinton, Cumberland and 31 more | 2 hr |
| Mar 7, 1:53 AM CST | Mesoscale Discussion | SPC | Champaign, Coles, Cumberland, Douglas, Edgar, Iroquois and 3 more | 97 min |
| Mar 7, 2:58 AM CST | Mesoscale Discussion | SPC | Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more | 92 min |
| Mar 6, 6:11 PM CST | Mesoscale Discussion | SPC | Adair, Adams, Allamakee, Appanoose, Audubon, Benton and 57 more | 2 hr |
Nearby
Mesoscale Discussions in Iowa, 2017Mesoscale Discussions in Illinois, 2017Every mesoscale discussion in 2017
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.