Alert archive / Illinois / Mesoscale Discussions in 2017

Mesoscale Discussion 219

February 28, 201730 counties in Illinois; 8 counties in Indiana; 10 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Feb 28, 2017, 2:03 PM CST for 30 counties in Illinois; 8 counties in Indiana; 10 counties in Iowa. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Feb 28, 2017, 2:03 PM CST (20:03 UTC)
Expired
Feb 28, 2017, 4:30 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 48 counties

Clinton County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Lee County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Bureau County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McDonough County, IL, McLean County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Starke County, IN, White County, IN

The radar

The Quad Cities radar (KDVN), 108 km from the middle of the area, began a volume at 20:04 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 12:00Z, 8.1 hours before the alert went out and 102 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, Davenport, at 12:00Z on 2017-02-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 30 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, Davenport, at 12:00Z on 2017-02-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 223 square meters per square second.1939587897117Sfc1 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
30 J/kg
Mixed-layer CIN
-241 J/kg
Mixed-layer LCL
771 m above ground
0-6 km bulk shear
80 kt
0-1 km storm-relative helicity
223 m²/s²
0-3 km storm-relative helicity
294 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 28, 1:46 PM CSTMesoscale DiscussionSPCAlexander, Franklin, Jackson, Jefferson, Johnson, Massac and 8 more2 hr
Feb 28, 2:19 PM CSTTornado WatchSPCAlexander, Bond, Calhoun, Clinton, Edwards, Fayette and 27 more7 hr
Feb 28, 2:57 PM CSTTornado WatchSPCAdams, Boone, Brown, Bureau, Carroll, Cass and 63 more7 hr
Feb 28, 5:24 PM CSTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 28 more96 min
Feb 28, 5:28 PM CSTMesoscale DiscussionSPCAlexander, Jackson, Johnson, Massac, Pope, Pulaski and 2 more2 hr

Nearby

Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Iowa, 2017Mesoscale Discussions in Indiana, 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.