Alert archive / Illinois / Tornado Watches in 2017
Tornado Watch 48
The Storm Prediction Center issued this tornado watch at Feb 28, 2017, 9:51 PM CST for 43 counties in Illinois; 5 counties in Indiana. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 28, 2017, 9:51 PM CST (03:51 UTC)
- Expired
- Mar 1, 2017, 4:00 AM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 48 counties
Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Coles County, IL, Cook County, IL, Crawford County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Iroquois County, IL, Jasper County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Lawrence County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Peoria County, IL, Piatt County, IL, Richland County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Tazewell County, IL, Vermilion County, IL, Will County, IL, Woodford County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN
The radar
The Lincoln radar (KILX), 26 km from the middle of the area, began a volume at 03:50 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 50%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 50%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 28, 10:18 PM CST | Severe Thunderstorm Warning | LOT | DeKalb, DuPage, Grundy, Kane, Kendall, Will | 27 min |
| Feb 28, 10:44 PM CST | Severe Thunderstorm Warning | ILX | McLean | 46 min |
| Feb 28, 11:32 PM CST | Severe Thunderstorm Warning | LOT | Jasper, Lake, Porter | 28 min |
| Mar 1, 12:04 AM CST | Severe Thunderstorm Warning | LOT | Jasper, Newton | 26 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 3.9 hours before the alert went out and 39 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
- 687 J/kg
- Mixed-layer CIN
- -73 J/kg
- Mixed-layer LCL
- 887 m above ground
- 0-6 km bulk shear
- 72 kt
- 0-1 km storm-relative helicity
- 395 m²/s²
- 0-3 km storm-relative helicity
- 431 m²/s²
- Significant tornado parameter
- 1.6
- Supercell composite
- 6.7
The text
As transmitted.
007 WWUS20 KWNS 010349 SEL8 SPC WW 010349 ILZ000-INZ000-LMZ000-011000- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 48 NWS Storm Prediction Center Norman OK 950 PM CST Tue Feb 28 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Central, northern and eastern Illinois Northwestern Indiana Lake Michigan * Effective this Tuesday night and Wednesday morning from 950 PM until 400 AM CST. * Primary threats include... A few tornadoes possible Scattered damaging wind gusts to 70 mph possible Isolated very large hail events to 2 inches in diameter possible SUMMARY...The severe-storm threat (including tornadoes) will continue for several more hours overnight past the expiration of tornado watch 42; therefore, this tornado watch effectively will replace it for the designated counties. Please see SPC mesoscale discussion 225 for initial meteorological reasoning. The tornado watch area is approximately along and 75 statute miles east and west of a line from 35 miles south southwest of Decatur IL to 25 miles east northeast of Marseilles IL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 42...WW 43...WW 44...WW 45...WW 46...WW 47... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 26035. ...Edwards
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 28, 7:46 PM CST | Mesoscale Discussion | SPC | Alexander, Clay, Crawford, Edwards, Franklin, Gallatin and 21 more | 119 min |
| Feb 28, 8:06 PM CST | Mesoscale Discussion | SPC | Adams, Brown, Bureau, Cass, Champaign, Christian and 37 more | 84 min |
| Feb 28, 8:29 PM CST | Tornado Watch | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more | 12 hr |
| Feb 28, 9:04 PM CST | Tornado Watch | SPC | Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more | 7 hr |
| Feb 28, 10:09 PM CST | Mesoscale Discussion | SPC | Edwards, Franklin, Gallatin, Hamilton, Jackson, Johnson and 5 more | 66 min |
| Feb 28, 11:52 PM CST | Mesoscale Discussion | SPC | Champaign, Ford, Iroquois, Vermilion | 53 min |
| Mar 1, 2:09 AM CST | Mesoscale Discussion | SPC | Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more | 2 hr |
| Mar 1, 3:03 AM CST | Tornado Watch | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more | 5 hr |
| Mar 1, 4:19 AM CST | Mesoscale Discussion | SPC | Alexander, Gallatin, Hardin, Johnson, Massac, Pope and 3 more | 56 min |
| Feb 28, 6:00 PM CST | Mesoscale Discussion | SPC | Adams, Allen, Cass, DeKalb, Elkhart, Fulton and 14 more | 90 min |
| Feb 28, 6:37 PM CST | Severe Thunderstorm Watch | SPC | Allen, DeKalb, Elkhart, Fulton, Kosciusko, LaGrange and 8 more | 8 hr |
| Feb 28, 8:41 PM CST | Mesoscale Discussion | SPC | Allen, DeKalb, Elkhart, Fulton, Kosciusko, LaGrange and 9 more | 94 min |
| Feb 28, 10:03 PM CST | Mesoscale Discussion | SPC | Adams, Allen, Bartholomew, Blackford, Boone, Carroll and 48 more | 117 min |
| Feb 28, 10:29 PM CST | Tornado Watch | SPC | Adams, Allen, Blackford, Boone, Carroll, Cass and 41 more | 8 hr |
| Mar 1, 12:44 AM CST | Mesoscale Discussion | SPC | Adams, Allen, Blackford, Boone, Carroll, Cass and 28 more | 61 min |
| Mar 1, 1:32 AM CST | Mesoscale Discussion | SPC | Clark, Crawford, Dearborn, Dubois, Floyd, Harrison and 11 more | 88 min |
| Mar 1, 4:57 AM CST | Tornado Watch | SPC | Clark, Crawford, Dearborn, Dubois, Floyd, Franklin and 9 more | 5 hr |
Nearby
Tornado Watches in Illinois, 2017Tornado Watches in Indiana, 2017Every tornado watch 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.