Dense Fog Advisories in Illinois, 2019

Dense Fog Advisories by county

Each county as a circle sized by its count in 2019. Tap one for its archive.

Over time

By month

The alerts

Every alert, in the order issued. Times are local, Central Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Counties	Lasted
Jan 14, 2:30 AM CST	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Mercer, Rock Island, Warren	6 hr
Jan 14, 3:54 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Coles, DeWitt, Douglas and 20 more	8 hr
Jan 14, 5:31 AM CST	Dense Fog Advisory	LOT	Ford, Iroquois, Kankakee, Livingston	3 hr
Jan 14, 9:28 AM CST	Dense Fog Advisory	LOT	Ford, Iroquois, Kankakee, Livingston	3 hr
Jan 17, 4:10 AM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	8 hr
Jan 17, 8:57 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 21 more	7 hr
Feb 2, 2:59 AM CST	Dense Fog Advisory	PAH	Alexander, Franklin, Hamilton, Jackson, Jefferson, Johnson and 6 more	6 hr
Feb 2, 3:34 AM CST	Dense Fog Advisory	LSX	Bond, Clinton, Fayette, Madison, Marion, Monroe and 3 more	8 hr
Feb 2, 7:23 AM CST	Dense Fog Advisory	ILX	Clark, Clay, Coles, Crawford, Cumberland, Douglas and 7 more	5 hr
Feb 2, 9:03 AM CST	Dense Fog Advisory	PAH	Alexander, Franklin, Hamilton, Jackson, Jefferson, Johnson and 6 more	117 min
Feb 2, 2:49 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Henry, Jo Daviess, Mercer, Putnam and 3 more	33 hr
Feb 2, 7:12 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	6 hr
Feb 2, 7:41 PM CST	Dense Fog Advisory	ILX	Champaign, Clark, Coles, Cumberland, DeWitt, Douglas and 9 more	4 hr
Feb 3, 8:50 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Kane, Lake, Lee, McHenry and 2 more	15 hr
Feb 5, 1:49 PM CST	Dense Fog Advisory	PAH	Alexander	16 hr
Feb 6, 8:43 PM CST	Dense Fog Advisory	PAH	Edwards, Franklin, Hamilton, Jackson, Jefferson, Perry and 5 more	6 hr
Feb 6, 8:50 PM CST	Dense Fog Advisory	LSX	Bond, Clinton, Fayette, Madison, Marion, Monroe and 3 more	9 hr
Feb 6, 8:53 PM CST	Dense Fog Advisory	ILX	Champaign, Clark, Clay, Coles, Crawford, Cumberland and 11 more	9 hr
Feb 7, 9:21 AM CST	Dense Fog Advisory	LOT	DeKalb, DuPage, Ford, Grundy, Iroquois, Kane and 6 more	5 hr
Feb 7, 9:38 AM CST	Dense Fog Advisory	ILX	Champaign, Christian, Coles, DeWitt, Douglas, Edgar and 8 more	3 hr
Feb 10, 8:55 PM CST	Dense Fog Advisory	LSX	Adams, Brown, Calhoun, Greene, Jersey, Macoupin and 2 more	13 hr
Feb 10, 9:01 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	12 hr
Feb 11, 2:23 AM CST	Dense Fog Advisory	LOT	Ford, Iroquois, Livingston	6 hr
Feb 12, 7:57 AM CST	Dense Fog Advisory	LOT	DeKalb, DuPage, Ford, Grundy, Iroquois, Kane and 6 more	2 hr
Feb 20, 9:09 AM CST	Dense Fog Advisory	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 8 more	3 hr
Feb 23, 5:32 PM CST	Dense Fog Advisory	LSX	Adams, Brown, Pike	3 hr
Feb 23, 6:21 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	5 hr
Apr 5, 3:12 AM CDT	Dense Fog Advisory	ILX	Cass, Christian, Fulton, Logan, Mason, Menard and 4 more	6 hr
Apr 5, 3:34 AM CDT	Dense Fog Advisory	LSX	Adams, Brown, Calhoun, Greene, Jersey, Macoupin and 2 more	5 hr
Apr 5, 3:54 AM CDT	Dense Fog Advisory	DVN	Hancock, McDonough	6 hr
Apr 6, 2:04 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	8 hr
Apr 6, 5:03 AM CDT	Dense Fog Advisory	LOT	DeKalb, DuPage, Ford, Grundy, Iroquois, Kane and 5 more	4 hr
Apr 9, 5:27 AM CDT	Dense Fog Advisory	PAH	Massac	4 hr
Apr 25, 1:33 AM CDT	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 10 more	8 hr
Apr 25, 1:47 AM CDT	Dense Fog Advisory	ILX	Cass, Christian, Clay, Crawford, Effingham, Jasper and 8 more	8 hr
Apr 25, 4:06 AM CDT	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Mercer, Warren	6 hr
May 2, 1:29 AM CDT	Dense Fog Advisory	PAH	Edwards, Gallatin, Hamilton, Wabash, Wayne, White	6 hr
May 2, 2:48 AM CDT	Dense Fog Advisory	ILX	Champaign, Clark, Clay, Coles, Crawford, Cumberland and 7 more	6 hr
May 3, 5:55 AM CDT	Dense Fog Advisory	DVN	Carroll, Henry, Jo Daviess, Mercer, Rock Island, Stephenson and 1 more	3 hr
May 3, 6:00 AM CDT	Dense Fog Advisory	LOT	Boone, McHenry, Ogle, Winnebago	3 hr
May 16, 2:55 AM CDT	Dense Fog Advisory	ILX	Clark, Clay, Crawford, Cumberland, Effingham, Jasper and 3 more	5 hr
Jun 15, 8:00 PM CDT	Dense Fog Advisory	LOT	Lake	14 hr
Jun 18, 4:26 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Kendall, Lake and 1 more	5 hr
Jul 6, 4:57 AM CDT	Dense Fog Advisory	LSX	Adams, Brown, Pike	3 hr
Aug 8, 3:37 AM CDT	Dense Fog Advisory	PAH	Alexander, Gallatin, Hardin, Johnson, Massac, Pope and 4 more	4 hr
Aug 12, 4:29 AM CDT	Dense Fog Advisory	DVN	Carroll, Jo Daviess, Stephenson	5 hr
Aug 14, 6:32 AM CDT	Dense Fog Advisory	LOT	Ford, Grundy, Iroquois, Kankakee, LaSalle, Lee and 1 more	88 min
Aug 14, 6:38 AM CDT	Dense Fog Advisory	DVN	Bureau, Putnam, Whiteside	96 min
Aug 21, 4:46 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	4 hr
Sep 1, 9:41 PM CDT	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	12 hr
Sep 2, 1:19 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	8 hr
Sep 2, 2:45 AM CDT	Dense Fog Advisory	DVN	Bureau, Hancock, Henderson, Henry, McDonough, Mercer and 2 more	6 hr
Sep 2, 4:47 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Ford, Grundy, Iroquois, Kane and 8 more	3 hr
Sep 15, 9:07 PM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Henderson, Henry, Jo Daviess, Mercer and 5 more	13 hr
Sep 15, 9:12 PM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Kane, Kendall, Lake, LaSalle and 4 more	13 hr
Sep 16, 3:34 AM CDT	Dense Fog Advisory	ILX	Knox, Marshall, Peoria, Stark, Woodford	6 hr
Sep 16, 8:04 PM CDT	Dense Fog Advisory	LOT	Lake	13 hr
Sep 30, 1:40 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Kendall, Lake and 3 more	7 hr
Oct 19, 8:19 PM CDT	Dense Fog Advisory	DVN	Hancock, Henderson, Jo Daviess, McDonough, Mercer, Rock Island and 1 more	15 hr
Oct 19, 8:36 PM CDT	Dense Fog Advisory	LSX	Adams, Brown, Pike	14 hr
Oct 20, 8:36 PM CDT	Dense Fog Advisory	LOT	Lake	7 hr
Oct 27, 1:54 AM CDT	Dense Fog Advisory	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 8 more	8 hr
Nov 19, 9:29 PM CST	Dense Fog Advisory	LSX	Bond, Brown, Calhoun, Clinton, Fayette, Greene and 7 more	9 hr
Nov 19, 9:36 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	11 hr
Nov 19, 9:42 PM CST	Dense Fog Advisory	PAH	Edwards, Franklin, Gallatin, Hamilton, Hardin, Jefferson and 5 more	11 hr
Nov 20, 12:18 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Henderson, Henry, Jo Daviess, McDonough and 6 more	10 hr
Nov 20, 4:42 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Ford, Grundy, Kendall, LaSalle and 4 more	6 hr
Dec 1, 2:48 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Lake, McHenry and 2 more	9 hr
Dec 7, 9:18 PM CST	Dense Fog Advisory	PAH	Alexander, Jackson, Pulaski, Union	13 hr
Dec 9, 2:02 AM CST	Dense Fog Advisory	DVN	Jo Daviess, Stephenson	7 hr
Dec 13, 9:11 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	12 hr
Dec 14, 2:11 AM CST	Dense Fog Advisory	ILX	Champaign, Clark, Clay, Coles, Crawford, Cumberland and 7 more	7 hr
Dec 14, 2:50 AM CST	Dense Fog Advisory	LSX	Bond, Clinton, Fayette, Marion, Randolph, Washington	4 hr
Dec 24, 1:58 AM CST	Dense Fog Advisory	ILX	Champaign, Christian, Clark, Clay, Coles, Crawford and 17 more	8 hr
Dec 24, 3:08 AM CST	Dense Fog Advisory	LOT	Boone, DuPage, Kane, McHenry, Winnebago	7 hr
Dec 24, 3:27 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Jo Daviess, Putnam, Stephenson, Whiteside	7 hr
Dec 26, 11:26 PM CST	Dense Fog Advisory	PAH	Alexander, Johnson, Massac, Pope, Pulaski, Union	9 hr
Dec 28, 4:30 AM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	7 hr
Dec 28, 8:52 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Coles, Crawford and 26 more	2 hr
Dec 28, 9:46 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	10 hr

By county

Every county with at least one alert. A county page lists each alert that covered it.

60 more counties

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record The radar archive 2018 2020

Sources

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.