Fog forecast — Friday 16 October

dashboard · tonight · 7-day outlook · region: Kankakee / Bourbonnais

run 2026-10-16T00:24-05:00 · Platt-calibrated on 329 station-mornings (2026-08-21..2026-10-15 at GYY, IKK, JOT, LOT, PNT, RZL)

No fog morning.

fog probability at home 1 % · high confidence

Typeshallow ground fog · 0–3 m, if any (estimate) Sky at sunriseno fog expected; mid+high cloud at sunrise ≈ 0 %, plus a low deck ≈ 72 % with visibility 17 km (stratus, not fog) — flat grey, no beams If you go06:36 (civil dawn) · sunrise 07:04 at 101.3° ESE Beamssun 2°–12° up: 07:18–08:15 At sunrise9.9 °C / 50 °F, wind 13 kt (HRRR) Burn-offnot applicable at this probability

Why: the primary model never brings T−Td under 1 °C (minimum 2.4 °C); anything that forms will be thin patches over water and the wettest low ground.
HRRR profile at KIKK 07:00 (run 2026-10-15 19:00): no level saturated (T−Td ≤ 1 °C), temperature change 10 m → 80 m: -0.7 °C — profile shows no saturated layer at the airport; any fog will be local to low ground and water
4 models within 0.07 of each other on the blend score

Sites, best first

site	fog	grade	type	light	sunrise	drive	drone
Home (Bourbonnais, 60914)	1 %	F	shallow ground fog	overcast above the fog	07:04 · 101.3° ESE	— min	unknown
Midewin National Tallgrass Prairie - Iron Bridge Trailhead	1 %	F	shallow ground fog	overcast above the fog	07:05 · 101.3° ESE	43 min	allowed
Kankakee River State Park	1 %	F	shallow ground fog	overcast above the fog	07:05 · 101.3° ESE	12 min	permit
Perry Farm Park	1 %	F	shallow ground fog	overcast above the fog	07:04 · 101.3° ESE	5 min	unknown
Bird Park	1 %	F	shallow ground fog	overcast above the fog	07:04 · 101.3° ESE	7 min	unknown
Kankakee Sands - Illinois (The Nature Conservancy)	1 %	F	shallow ground fog	overcast above the fog	07:03 · 101.3° ESE	37 min	prohibited
Island Park (Momence)	1 %	F	shallow ground fog	overcast above the fog	07:03 · 101.3° ESE	29 min	unknown
Momence Wetlands Nature Preserve	1 %	F	shallow ground fog	overcast above the fog	07:03 · 101.3° ESE	38 min	permit
Des Plaines State Fish and Wildlife Area	1 %	F	shallow ground fog	overcast above the fog	07:06 · 101.3° ESE	48 min	permit
Iroquois County State Wildlife Area	1 %	F	shallow ground fog	overcast above the fog	07:03 · 101.3° ESE	55 min	permit

Home (Bourbonnais, 60914) — 1 %, shallow ground fog

Where41.1530, -87.8790 · map Featurescorn, tree line Accessnot verified Droneunknown — no rule found Suncivil dawn 06:36, sunrise 07:04 at 101.3°, beams 07:18–08:15 Burn-off07:19–07:49 est.; HRRR clears n/a Rain 48 h7.7 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.30 — min T−Td in the 3 h before sunrise = 2.4 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 13.8 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.64 — overnight mid+high levels cloud = 47 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 10.0 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 9.9 °C vs afternoon dewpoint 16.7 °C → -6.8 °C; rain last 48 h = 7.7 mm; BUT dewpoint falls 9.6 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 15.7 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 14 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 95 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.042, ncep_nbm_conus 0.086, ecmwf_ifs025 0.017, icon_seamless 0.048 · spread 0.069

local	T	Td	T−Td	wind	low	mid	vis km
21:00	20.7	19.9	0.8	11.1	100	2	12.2
22:00	19.8	18.8	1.0	12.3	100	11	12.4
23:00	18.4	16.9	1.5	17.3	100	0	13.4
00:00	16.2	14.4	1.8	16.0	100	100	14.2
01:00	15.0	12.7	2.3	14.5	100	100	15.7
02:00	13.6	11.2	2.4	15.0	100	100	15.9
03:00	12.0	9.6	2.4	15.5	100	100	16.1
04:00	11.3	8.9	2.4	15.1	100	100	15.7
05:00	11.3	8.4	2.9	13.4	100	0	17.0
06:00	10.9	7.9	3.0	13.3	100	0	17.2
07:00	9.9	7.1	2.8	13.2	45	0	16.6
08:00	10.1	7.0	3.1	12.8	100	0	17.2
09:00	10.3	6.5	3.8	12.5	100	0	19.1
10:00	10.0	6.3	3.7	13.1	100	0	18.1
11:00	10.6	6.5	4.1	12.0	100	0	19.0

Midewin National Tallgrass Prairie - Iron Bridge Trailhead — 1 %, shallow ground fog

Where41.3789, -88.1231 · map Featuresprairie, tree line, farmland Lookdeep-bank aerial over prairie + tree rows; lone-tree shots from the trail Access"Visitors and trail users are welcome to the open areas of Midewin every day of the year from 4 am until 10 pm." (hiking page); trailhead page: "Trails: year-round, Mon - Sun, 4:00 a.m. to 10:00 p.m. (Closed on federal holidays)" Droneallowed — Midewin links to the national FS page: "Individuals and organizations may fly UAS for hobby or recreational purposes"; "UAS must be flown below 400 feet"; "Keep your UAS away from populated and noise-sensitive areas, such as campgrounds, trail heads, and visitor centers." Midewin safety page: "Avoid Drone Use Near Bison". Forest Orders page: "Currently there are no active Forest Orders at Midewin National Tallgrass Prairie." No Midewin-specific filming/commercial permit rule found. source AirspaceFAA Class_Airspace data: Chicago Class E5 (floor 700 ft AGL) + Illinois Class E5; surface is Class G. No UAS Facility Map grid. KJOT 8.7 nm, Dresden Generating Station 6.6 nm, Braidwood 9.4 nm. Not in any national-security UAS restriction layer. NotesDrive time is an OSRM estimate. FS tips page cites Section 336 (outdated wording) and says to fly >=5 miles from an airport (KJOT is 8.7 nm away). Bison are present at Midewin; location of herd vs this trailhead not verified. Suncivil dawn 06:37, sunrise 07:05 at 101.3°, beams 07:19–08:17 Burn-off07:20–07:50 est.; HRRR clears n/a Rain 48 h10.1 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.32 — min T−Td in the 3 h before sunrise = 2.3 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 13.3 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 1.00 — overnight mid+high levels cloud = 14 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 9.2 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.38 — crossover: forecast night minimum 10.0 °C vs afternoon dewpoint 16.5 °C → -6.5 °C; rain last 48 h = 10.1 mm; BUT dewpoint falls 9.1 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 15.7 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 13 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 100 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.051, ncep_nbm_conus 0.077, ecmwf_ifs025 0.019, icon_seamless 0.052 · spread 0.058

local	T	Td	T−Td	wind	low	mid	high	vis km
21:00	19.9	19.0	0.9	11.7	100	4	0	12.3
22:00	19.4	18.1	1.3	13.2	100	4	0	6.1
23:00	17.0	15.5	1.5	14.2	100	0	0	13.9
00:00	14.9	13.1	1.8	14.1	100	47	0	14.5
01:00	14.1	12.1	2.0	15.0	100	100	0	14.8
02:00	12.7	10.4	2.3	15.0	100	0	0	15.9
03:00	11.7	9.4	2.3	14.8	100	0	1	15.9
04:00	11.3	9.0	2.3	13.5	100	0	0	15.7
05:00	11.0	8.7	2.3	13.5	100	0	0	16.0
06:00	10.5	8.0	2.5	13.5	100	0	0	16.1
07:00	10.0	7.4	2.6	12.7	100	0	0	16.9
08:00	10.0	6.8	3.2	11.8	100	0	0	18.0
09:00	9.3	6.7	2.6	13.2	100	0	0	16.8
10:00	9.7	7.1	2.6	12.6	100	0	0	16.7
11:00	9.9	7.1	2.8	12.0	100	0	0	17.1

Kankakee River State Park — 1 %, shallow ground fog

Where41.2030, -87.9790 · map Featuresriver, river-valley relief Lookriver steam fog in the valley; rim gives an elevated view over the fog (drone needs IDNR authorization) AccessNo opening hours on the park page. Activities page: "Quiet hours are 10 p.m. to 7 a.m. Vehicle traffic is not allowed during quiet hours." Dronepermit — 17 Ill. Adm. Code 110.160(i): it is unlawful "Except in cases of emergency, for any person to land or attempt to land any aircraft on Department-owned, -leased or -managed property without prior authorization for each landing or attempted landing from the Department." No site-specific drone page found for this site. The wording says 'aircraft', not 'drone/unmanned', and does not name the superintendent; treat as authorization required until the site office says otherwise. source AirspaceIllinois Class E5 only (floor 1200 ft AGL); surface is Class G. KIKK 9.9 nm. Private strips nearby: Hawker (12IL) 1.7 nm, Classic Landings (05IL) 3.3 nm (OSM/FAA IDs). NotesVehicle ban until 7:00 am means pre-sunrise access by car is not allowed; sunrise is roughly 7:00-7:10 am CDT now but about 6:20-6:40 am CST after Nov 1. Walk-in before 7 is not addressed on the page. Park office: 815-933-1383, Mon-Fri 8:00-3:30 (metal detecting permit text). Hunting seasons run in the park (archery deer, waterfowl, upland). Suncivil dawn 06:36, sunrise 07:05 at 101.3°, beams 07:19–08:16 Burn-off07:20–07:50 est.; HRRR clears n/a Riverriver water +8.9 °C warmer than the forecast dawn air (steam fog over open water needs roughly ≥5 °C and light wind; forecast wind 14 kt) Rain 48 h9.4 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.28 — min T−Td in the 3 h before sunrise = 2.5 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 13.8 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.66 — overnight mid+high levels cloud = 46 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 10.3 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.37 — crossover: forecast night minimum 9.9 °C vs afternoon dewpoint 16.9 °C → -7.0 °C; rain last 48 h = 9.4 mm; BUT dewpoint falls 9.6 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.0 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 14 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 99 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.041, ncep_nbm_conus 0.092, ecmwf_ifs025 0.017, icon_seamless 0.036 · spread 0.075

local	T	Td	T−Td	wind	low	mid	vis km
21:00	20.5	19.6	0.9	10.9	89	0	12.2
22:00	19.9	18.8	1.1	13.1	100	2	12.7
23:00	18.1	16.4	1.7	16.5	100	0	14.0
00:00	15.8	14.3	1.5	17.3	100	100	13.5
01:00	14.9	12.7	2.2	15.4	100	100	15.1
02:00	13.5	11.0	2.5	15.3	100	100	16.0
03:00	12.1	9.4	2.7	16.8	100	100	16.4
04:00	11.5	9.0	2.5	15.5	100	100	16.0
05:00	11.4	8.6	2.8	14.3	100	0	17.0
06:00	10.9	8.1	2.8	13.6	100	1	17.0
07:00	9.9	7.3	2.6	11.9	100	0	16.7
08:00	10.1	7.1	3.0	13.6	100	0	17.3
09:00	9.9	6.8	3.1	14.0	100	0	17.8
10:00	9.7	6.7	3.0	14.1	100	0	17.4
11:00	10.5	7.0	3.5	13.7	100	0	18.7

Perry Farm Park — 1 %, shallow ground fog

Where41.1457, -87.8849 · map Featuresriver, river-valley relief, pond, orchard/farmstead Lookbluff ~70 ft above the river: ground-level view DOWN onto river fog without a drone; pond and orchard for lone-tree frames Access"Hours of Operation: Dawn until Dusk, Year Round" Droneunknown — no rule found; default is FAA recreational/Part 107 rules (<=400 ft AGL, visual line of sight, Class G needs no authorization) but unverified for this site AirspaceKankakee Class E5 (floor 700 ft AGL) + Illinois Class E5; surface is Class G. KIKK 4.8 nm (inside the roughly 4-5 nm ring where a Class E surface area would sit, but FAA data shows no surface area). No UAS Facility Map grid. Notesbtpd.org site search for 'drone' returns no results and the Rules and Regulations page has no aircraft clause. Illinois law (620 ILCS 5/42.1(b-5)) lets a park district adopt reasonable rules for airspace over its parkland, so call 815-933-9905 to confirm. Park coordinates are the OSM centroid, not the overlook. Suncivil dawn 06:36, sunrise 07:04 at 101.3°, beams 07:18–08:15 Burn-off07:19–07:49 est.; HRRR clears n/a Riverriver water +8.5 °C warmer than the forecast dawn air (steam fog over open water needs roughly ≥5 °C and light wind; forecast wind 14 kt) Rain 48 h7.7 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.28 — min T−Td in the 3 h before sunrise = 2.5 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 13.5 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.65 — overnight mid+high levels cloud = 47 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 9.8 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 10.3 °C vs afternoon dewpoint 17.1 °C → -6.8 °C; rain last 48 h = 7.7 mm; BUT dewpoint falls 9.6 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.0 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 14 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 95 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.041, ncep_nbm_conus 0.086, ecmwf_ifs025 0.017, icon_seamless 0.048 · spread 0.069

local	T	Td	T−Td	wind	low	mid	vis km
21:00	20.7	19.9	0.8	10.3	94	1	12.2
22:00	19.9	18.7	1.2	10.8	100	11	12.4
23:00	18.3	16.8	1.5	17.2	100	0	13.6
00:00	16.2	14.6	1.6	15.9	100	100	14.0
01:00	15.0	12.7	2.3	14.1	100	100	15.7
02:00	13.6	11.3	2.3	14.8	100	100	15.7
03:00	12.1	9.4	2.7	15.3	100	100	16.2
04:00	11.4	8.9	2.5	14.8	100	100	16.0
05:00	11.3	8.3	3.0	13.3	100	0	17.1
06:00	10.9	7.9	3.0	13.0	100	0	17.2
07:00	10.3	7.5	2.8	12.9	46	0	16.8
08:00	10.2	7.3	2.9	12.0	100	0	17.1
09:00	10.1	6.6	3.5	12.4	100	0	18.6
10:00	9.8	6.5	3.3	13.0	100	0	17.9
11:00	10.4	6.9	3.5	12.0	100	0	18.6

Bird Park — 1 %, shallow ground fog

Where41.1213, -87.8792 · map Featuresriver, open field, trees Lookriverfront + open field + mature trees; closest aerial option in Class G AccessOpening time not stated. Page lists: "Park Closes At Dusk" Droneunknown — no rule found; default is FAA recreational/Part 107 rules (<=400 ft AGL, visual line of sight, Class G needs no authorization) but unverified for this site AirspaceKankakee Class E5 (floor 700 ft AGL) + Illinois Class E5; surface is Class G. KIKK 3.3 nm. Kankakee Airport (3KK) 2.0 nm. No UAS Facility Map grid. NotesIn-town park (893 W. Station St., Kankakee). kvpd.com search for 'drone' returned a page with no match. Same Illinois (b-5) local-rule caveat as Perry Farm. Suncivil dawn 06:36, sunrise 07:04 at 101.3°, beams 07:18–08:15 Burn-off07:19–07:49 est.; HRRR clears n/a Riverriver water +8.1 °C warmer than the forecast dawn air (steam fog over open water needs roughly ≥5 °C and light wind; forecast wind 13 kt) Rain 48 h7.7 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.20 — min T−Td in the 3 h before sunrise = 2.8 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 12.9 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.65 — overnight mid+high levels cloud = 46 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 9.6 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 10.7 °C vs afternoon dewpoint 16.9 °C → -6.2 °C; rain last 48 h = 7.7 mm; BUT dewpoint falls 9.2 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.3 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 13 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 99 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.037, ncep_nbm_conus 0.087, ecmwf_ifs025 0.018, icon_seamless 0.048 · spread 0.069

local	T	Td	T−Td	wind	low	mid	vis km
21:00	21.0	20.0	1.0	10.0	100	2	12.5
22:00	20.1	18.6	1.5	10.2	100	9	13.2
23:00	18.8	17.1	1.7	17.0	100	0	13.9
00:00	16.6	14.8	1.8	14.5	100	100	14.4
01:00	15.2	12.5	2.7	13.6	100	100	16.1
02:00	13.7	11.2	2.5	14.2	96	100	15.7
03:00	12.2	9.5	2.7	14.9	100	100	16.3
04:00	11.5	8.7	2.8	14.1	100	100	16.3
05:00	11.5	8.4	3.1	12.9	100	0	17.4
06:00	11.1	7.9	3.2	12.3	100	0	17.4
07:00	10.7	7.7	3.0	12.4	90	0	16.9
08:00	10.4	7.5	2.9	11.0	100	0	17.2
09:00	10.3	6.4	3.9	11.4	100	0	19.2
10:00	10.0	6.5	3.5	11.7	100	0	18.2
11:00	10.4	6.7	3.7	11.2	100	0	18.4

Kankakee Sands - Illinois (The Nature Conservancy) — 1 %, shallow ground fog

Where41.0793, -87.6568 · map Featuresoak savanna, prairie, lone trees, sand dunes Lookbest lone-tree savanna terrain for the ground frame; NO drone Access"Open sunrise to sunset, 365 days a year" Droneprohibited — "Drones—aka personal aircraft, unmanned aircraft systems (UAS) and unmanned aerial vehicles (UAV): Self-propelled or other aircraft are prohibited from taking off, landing or being operated on any TNC preserve except for official TNC purposes, approved research or in an emergency landing situation." source AirspaceIllinois Class E5 only (floor 1200 ft AGL); surface is Class G. KIKK 8.6 nm. No UAS Facility Map grid. NotesBest-fit terrain for the lone-tree-in-fog look from the ground, but drones are prohibited. TNC page: deer hunting allowed on many preserves from October through first week of January (blaze orange suggested). Not the same as Kankakee Sands-Indiana (Morocco) or the Will County FPD Kankakee Sands Preserve. Suncivil dawn 06:35, sunrise 07:03 at 101.3°, beams 07:17–08:14 Burn-off07:18–07:48 est.; HRRR clears n/a Rain 48 h8.0 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.25 — min T−Td in the 3 h before sunrise = 2.6 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 15.3 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.54 — overnight mid+high levels cloud = 56 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 8.5 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 10.5 °C vs afternoon dewpoint 16.7 °C → -6.2 °C; rain last 48 h = 8.0 mm; BUT dewpoint falls 9.2 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.6 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 15 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 98 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.037, ncep_nbm_conus 0.087, ecmwf_ifs025 0.018, icon_seamless 0.025 · spread 0.069

local	T	Td	T−Td	wind	low	mid	vis km
21:00	21.3	20.5	0.8	11.4	100	6	12.2
22:00	20.3	18.8	1.5	10.1	100	8	13.7
23:00	19.7	17.7	2.0	14.2	100	0	14.8
00:00	17.3	15.8	1.5	14.1	100	100	13.3
01:00	15.2	13.0	2.2	15.9	100	100	15.4
02:00	14.1	11.8	2.3	15.9	100	100	15.5
03:00	12.6	10.0	2.6	17.1	100	100	16.8
04:00	11.5	8.7	2.8	17.2	100	100	16.8
05:00	11.2	8.6	2.6	15.2	100	100	16.6
06:00	10.8	8.1	2.7	14.4	100	0	16.9
07:00	10.5	7.5	3.0	14.5	73	0	17.2
08:00	10.0	7.2	2.8	12.6	100	100	16.8
09:00	10.3	6.8	3.5	12.5	100	0	19.1
10:00	9.6	6.5	3.1	13.6	100	0	17.7
11:00	10.1	6.8	3.3	12.8	100	0	18.4

Island Park (Momence) — 1 %, shallow ground fog

Where41.1630, -87.6548 · map Featuresriver, island, flat terrain Lookriver island, flat; steam fog over water AccessNone Droneunknown — no rule found; default is FAA recreational/Part 107 rules (<=400 ft AGL, visual line of sight, Class G needs no authorization) but unverified for this site AirspaceNo Class E polygon from the FAA data at this point; surface is Class G. KIKK 10.3 nm, Bult Field (C56) 12.9 nm. No UAS Facility Map grid. NotesTown-center park; no verified corn or tree-line view. No hours or drone rule on momence.org or momenceparkdistrict.org. visitkankakeecounty.com pages returned HTTP 403. Suncivil dawn 06:35, sunrise 07:03 at 101.3°, beams 07:17–08:14 Burn-off07:18–07:48 est.; HRRR clears n/a Riverriver water +8.1 °C warmer than the forecast dawn air (steam fog over open water needs roughly ≥5 °C and light wind; forecast wind 14 kt) Rain 48 h8.0 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.20 — min T−Td in the 3 h before sunrise = 2.8 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 14.5 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.52 — overnight mid+high levels cloud = 58 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 7.8 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 10.7 °C vs afternoon dewpoint 16.1 °C → -5.4 °C; rain last 48 h = 8.0 mm; BUT dewpoint falls 8.3 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.8 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 14 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 100 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.034, ncep_nbm_conus 0.084, ecmwf_ifs025 0.018, icon_seamless 0.025 · spread 0.066

local	T	Td	T−Td	wind	low	mid	vis km
21:00	21.4	20.4	1.0	9.8	100	32	12.5
22:00	20.4	18.7	1.7	12.5	100	49	14.1
23:00	19.7	18.2	1.5	15.3	100	0	13.5
00:00	17.1	15.2	1.9	14.4	100	100	14.3
01:00	15.1	12.8	2.3	15.0	100	66	15.4
02:00	14.1	12.2	1.9	15.5	96	100	14.9
03:00	12.6	10.0	2.6	16.0	100	100	16.3
04:00	11.7	8.9	2.8	16.1	100	100	16.9
05:00	11.5	8.7	2.8	14.1	100	91	16.8
06:00	11.1	8.3	2.8	13.9	100	0	16.9
07:00	10.7	7.8	2.9	13.9	100	0	17.4
08:00	10.2	7.0	3.2	12.6	100	95	17.4
09:00	10.6	6.5	4.1	13.0	100	0	20.3
10:00	10.0	6.5	3.5	13.3	100	0	18.4
11:00	10.6	6.7	3.9	12.5	100	0	19.1

Momence Wetlands Nature Preserve — 1 %, shallow ground fog

Where41.1643, -87.5542 · map Featuresriver, bottomland, floodplain forest Lookfloodplain forest: treetops-in-fog aerial if authorized AccessNone Dronepermit — 17 Ill. Adm. Code 110.160(i): it is unlawful "Except in cases of emergency, for any person to land or attempt to land any aircraft on Department-owned, -leased or -managed property without prior authorization for each landing or attempted landing from the Department." No site-specific drone page found for this site. The wording says 'aircraft', not 'drone/unmanned', and does not name the superintendent; treat as authorization required until the site office says otherwise. source AirspaceNo Class E polygon from the FAA data at this point; surface is Class G. KIKK 14.3 nm, Bult Field (C56) 14.1 nm. No UAS Facility Map grid. NotesPage gives only directions: "From Momence, take Highway 114 east 6 miles to a county road. Turn north on this road and go 0.75 mile. The preserve is on the west side of the road." No parking, trail or hours stated. 17 Ill. Adm. Code 110.120(b) bars entry to a dedicated nature preserve where posted rules prohibit it. Contact listed: Site Superintendent, Iroquois County Conservation Area, 815-435-2218. Suncivil dawn 06:34, sunrise 07:03 at 101.3°, beams 07:17–08:14 Burn-off07:18–07:48 est.; HRRR clears n/a Riverriver water +8.1 °C warmer than the forecast dawn air (steam fog over open water needs roughly ≥5 °C and light wind; forecast wind 14 kt) Rain 48 h6.8 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.23 — min T−Td in the 3 h before sunrise = 2.7 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 13.6 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.53 — overnight mid+high levels cloud = 57 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 7.5 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 10.7 °C vs afternoon dewpoint 16.1 °C → -5.4 °C; rain last 48 h = 6.8 mm; BUT dewpoint falls 8.4 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.6 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 14 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 100 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.036, ncep_nbm_conus 0.087, ecmwf_ifs025 0.018, icon_seamless 0.04 · spread 0.069

local	T	Td	T−Td	wind	low	mid	vis km
21:00	21.4	20.3	1.1	10.6	100	13	13.0
22:00	20.5	18.8	1.7	11.4	100	27	14.3
23:00	19.6	18.0	1.6	12.2	100	0	14.0
00:00	17.1	15.6	1.5	13.5	100	100	13.6
01:00	15.0	12.7	2.3	14.7	100	84	15.5
02:00	14.1	12.3	1.8	14.4	100	100	14.3
03:00	12.7	10.1	2.6	14.8	100	100	16.5
04:00	11.6	8.9	2.7	15.3	100	100	16.8
05:00	11.3	8.5	2.8	13.6	100	100	16.6
06:00	11.0	8.1	2.9	13.0	100	0	17.0
07:00	10.7	7.7	3.0	12.6	100	0	17.2
08:00	10.1	7.3	2.8	11.6	100	100	16.7
09:00	10.5	6.7	3.8	12.0	100	0	19.6
10:00	9.9	6.5	3.4	13.1	100	0	18.2
11:00	10.5	6.5	4.0	11.6	100	0	19.4

Des Plaines State Fish and Wildlife Area — 1 %, shallow ground fog

Where41.3720, -88.2070 · map Featuresriver, bottomland, prairie, ponds, open fields Lookbottomland + prairie + backwaters; over the 45-min line; Dresden station 3 nm AccessNone Dronepermit — 17 Ill. Adm. Code 110.160(i): it is unlawful "Except in cases of emergency, for any person to land or attempt to land any aircraft on Department-owned, -leased or -managed property without prior authorization for each landing or attempted landing from the Department." No site-specific drone page found for this site. The wording says 'aircraft', not 'drone/unmanned', and does not name the superintendent; treat as authorization required until the site office says otherwise. source AirspaceNo Class E polygon from the FAA data at this point; surface is Class G. Dresden Generating Station (nuclear) 3.0 nm, Braidwood 7.8 nm, KJOT 8.9 nm. FAA FDC 6/8818 advises avoiding airspace in close proximity to nuclear plants; no mapped hard restriction found. NotesDrive estimate is just over the 45-minute target. Hunting is a main use (IDNR activities page has a hunting section; hunting-season dates not checked). IDNR: "Boat ramps are closed seasonally from the end of October for pheasant hunting season thru mid-April"; hand trap and archery ranges are "Closed during pheasant season." General daily hours not found; equestrian trail "6 a.m. to 10 p.m. daily" is trail-specific. Suncivil dawn 06:37, sunrise 07:06 at 101.3°, beams 07:20–08:18 Burn-off07:21–07:51 est.; HRRR clears n/a Riverriver water +8.5 °C warmer than the forecast dawn air (steam fog over open water needs roughly ≥5 °C and light wind; forecast wind 11 kt) Rain 48 h11.7 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.30 — min T−Td in the 3 h before sunrise = 2.4 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.08 — mean 10 m wind in the 3 h before sunrise = 11.5 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 1.00 — overnight mid+high levels cloud = 14 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 9.2 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.38 — crossover: forecast night minimum 10.3 °C vs afternoon dewpoint 16.8 °C → -6.4 °C; rain last 48 h = 11.7 mm; BUT dewpoint falls 9.1 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.2 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 11 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 94 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.052, ncep_nbm_conus 0.094, ecmwf_ifs025 0.018, icon_seamless 0.056 · spread 0.076

local	T	Td	T−Td	wind	low	mid	vis km
21:00	20.0	19.2	0.8	10.3	100	10	12.4
22:00	19.5	18.4	1.1	11.3	100	3	4.3
23:00	17.0	15.2	1.8	13.0	92	0	14.6
00:00	15.1	13.1	2.0	11.9	100	29	14.9
01:00	14.3	12.5	1.8	14.0	100	100	14.7
02:00	12.7	10.3	2.4	13.8	100	9	16.5
03:00	11.9	9.4	2.5	12.8	100	0	16.4
04:00	11.5	9.1	2.4	11.7	100	0	16.3
05:00	11.2	8.8	2.4	12.0	100	0	16.4
06:00	10.3	7.9	2.4	11.7	46	0	16.2
07:00	10.3	7.7	2.6	10.5	100	0	16.9
08:00	10.2	7.1	3.1	10.9	100	0	18.0
09:00	9.5	6.7	2.8	11.9	100	0	17.2
10:00	9.9	7.2	2.7	11.7	96	0	17.1
11:00	10.2	7.2	3.0	11.2	100	0	17.4

Iroquois County State Wildlife Area — 1 %, shallow ground fog

Where40.9940, -87.5990 · map Featuresmarsh, sand ridges, savanna, prairie remnant Looklone trees on sand ridges, marsh fog; over the 45-min line; hunting-season access limits AccessNone Dronepermit — 17 Ill. Adm. Code 110.160(i): it is unlawful "Except in cases of emergency, for any person to land or attempt to land any aircraft on Department-owned, -leased or -managed property without prior authorization for each landing or attempted landing from the Department." No site-specific drone page found for this site. The wording says 'aircraft', not 'drone/unmanned', and does not name the superintendent; treat as authorization required until the site office says otherwise. source AirspaceNo Class E polygon from the FAA data at this point; surface is Class G. KIKK 12.1 nm. No UAS Facility Map grid. NotesOUTSIDE the 45-minute target (OSRM estimate 55 min) and kept because the terrain matches the lone-tree look. IDNR page: "The majority of the area, 2,000 acres, is managed as a public hunting area... Nonconsumptive recreation, in the form of hiking and nature study, is available when the facility is closed to hunting." Hunting seasons overlap Oct-Nov. IDNR: drones for any aspect of hunting are unlawful. Site office 815-435-2218. Suncivil dawn 06:35, sunrise 07:03 at 101.3°, beams 07:17–08:14 Burn-off07:18–07:48 est.; HRRR clears n/a Rain 48 h6.7 mm (Open-Meteo ICON assimilated past days (model analysis, not a gauge))

Factors (HRRR):

dewpoint depression: 0.25 — min T−Td in the 3 h before sunrise = 2.6 °C (≤1 °C strongly favours fog, >3 °C rarely fogs)
wind: 0.00 — mean 10 m wind in the 3 h before sunrise = 14.9 kt (2–5 kt ideal; calm gives only shallow fog; >8 kt mixes it out)
sky: 0.48 — overnight mid+high levels cloud = 62 % (clear sky lets the ground radiate and cool)
cooling: 0.40 — temperature fall 18:00 → sunrise = 8.4 °C; part of this is cold advection, not radiation (discounted)
moisture: 0.36 — crossover: forecast night minimum 10.8 °C vs afternoon dewpoint 16.5 °C → -5.7 °C; rain last 48 h = 6.7 mm; BUT dewpoint falls 8.8 °C by dawn — drier air moving in, crossover rule discounted
model signal: 0.10 — model's own visibility minimum before sunrise = 16.3 km (0 h ≤ 1 km overnight)
GATE ×0.25: wind 15 kt: too much mixing for radiation fog
GATE ×0.6: low cloud deck 98 % overnight with good visibility: stratus, not fog

per-model blend: gfs_hrrr 0.036, ncep_nbm_conus 0.074, ecmwf_ifs025 0.018, icon_seamless 0.023 · spread 0.056

local	T	Td	T−Td	wind	low	mid	vis km
21:00	22.0	21.0	1.0	15.3	100	81	12.5
22:00	20.8	19.1	1.7	10.4	100	0	14.3
23:00	20.1	18.1	2.0	12.6	100	13	14.9
00:00	17.7	16.3	1.4	14.7	100	100	13.6
01:00	15.5	13.0	2.5	15.9	100	92	16.0
02:00	14.3	11.8	2.5	16.4	100	100	16.1
03:00	12.8	10.2	2.6	17.3	100	100	16.7
04:00	11.6	9.0	2.6	17.1	100	98	16.3
05:00	11.3	8.7	2.6	14.3	100	100	16.5
06:00	11.0	8.3	2.7	14.6	100	0	16.9
07:00	10.8	7.7	3.1	13.6	83	0	17.8
08:00	10.3	7.4	2.9	13.1	100	100	17.5
09:00	10.4	7.1	3.3	12.7	85	0	18.0
10:00	9.9	6.4	3.5	13.8	100	0	18.1
11:00	10.1	6.4	3.7	13.0	100	0	18.5

Independent checks

NBM bulletin for KIKK (cycle 2026-10-16T04:00:00+00:00, NOAA's own blend; P = probability)

local	T °F	Td °F	wind	sky %	vis mi	P(vis<1 mi)	P(vis<3 mi)	ceiling
03:00	53	50	15	96	10.0	1 %	1 %	13
04:00	51	48	14	91	10.0	0 %	0 %	15
05:00	50	47	14	89	10.0	0 %	0 %	15
06:00	48	46	14	77	10.0	0 %	0 %	13
07:00	47	44	13	71	10.0	0 %	0 %	15
08:00	47	45	13	54	10.0	0 %	0 %	18
09:00	49	44	14	67	10.0	0 %	0 %	18

HRRR vertical profile at KIKK (run 2026-10-15 19:00 local, Penn State BUFKIT; saturated depth = height to which T−Td ≤ 1 °C)

local	inversion (80 m − 10 m)	lowest levels (m AGL: T / Td)
03:00	-0.7 °C	11: 13.2/10.6 · 36: 13.0/10.3 · 82: 12.5/10.1 · 162: 11.7/9.8
04:00	-0.7 °C	10: 11.8/9.1 · 36: 11.6/8.8 · 82: 11.1/8.6 · 161: 10.3/8.3
05:00	-0.7 °C	10: 11.4/8.4 · 36: 11.2/8.2 · 81: 10.7/8.0 · 161: 10.0/7.7
06:00	-0.7 °C	11: 11.1/8.2 · 36: 10.9/7.9 · 81: 10.4/7.7 · 161: 9.7/7.3
07:00	-0.7 °C	11: 10.5/8.0 · 35: 10.2/7.8 · 82: 9.8/7.6 · 161: 9.0/7.3
08:00	-0.7 °C	11: 10.1/7.5 · 35: 9.8/7.2 · 82: 9.4/7.0 · 160: 8.6/6.7
09:00	-0.8 °C	11: 9.9/6.6 · 35: 9.6/6.3 · 81: 9.1/6.1 · 160: 8.4/5.8

Right now at KIKK
METAR KIKK 160515Z AUTO 30011G22KT 10SM SCT008 SCT013 OVC018 15/14 A2988 RMK AO2 T01500136
Observed T−Td 1.4 °C vs HRRR for this hour 1.8 °C — a model running dry or moist shows here.

Rivers (USGS)

KANKAKEE RIVER AT MOMENCE, IL: stage 2.10 ft
IROQUOIS RIVER NEAR CHEBANSE, IL: stage 2.92 ft
KANKAKEE RIVER NEAR WILMINGTON, IL: stage 1.59 ft, water 18.8 °C

NWS Chicago forecast discussion 2026-10-15T23:37:00+00:00

The primary low-pressure system will track directly over northern Illinois early this evening, then deepen as it shifts northeast into lower Michigan tonight. Expect a brief period of lower ceilings and reduced visibility for a few hours as the low moves overhead. Conditions will improve rapidly later tonight following a sharp cold front. In its wake, northwest winds will become gusty (3035 mph) overnight, while strong cold air advection drops temperatures into the 40s to low 50s by early Friday morning. Breezy conditions (gusts of 35 to 40 mph) will persist through Friday due to strong pressure rises behind the departing low and ahead of a 1035+ mb surface high building in from the Plains. Even stronger northerly winds (~45 mph) are projected over southern Lake Michigan Friday afternoon and evening. Onshore flow will push some of these higher winds inland across far northern Porter County, Indiana, where a Wind Advisory is in effect from 1:00 PM to 10:00 PM CDT Friday.

Were you out there?

One tap at dawn. This is the only truth the tool gets from the field; the airport sensor cannot see a river bottom.

Verification so far

morning	run	forecast	grade	airport min vis	airport fog?	field report	cam
2026-10-16	evening	1 %	F	—	pending	—	frame frame frame
2026-10-16	predawn	1 %	F	—	pending	—	frame frame frame

Honesty notes

Probability is a blend of HRRR, NBM, ECMWF and ICON point forecasts (model output). Type, depth and burn-off are rules of thumb (estimates) unless marked 'model profile'.
Calibrated on 329 airport mornings (2026-08-21..2026-10-15 at GYY, IKK, JOT, LOT, PNT, RZL). Airports fog less than river bottoms; read site rows as a ranking.
Backtest, in-sample (329 airport mornings, 34 fog cases on 13 distinct mornings): forecasts in each band verified as 0.0–0.1: fog 4 % of 191; 0.1–0.2: fog 16 % of 81; 0.2–0.3: fog 15 % of 46; 0.3–0.4: fog 50 % of 10. Ranking skill AUC 0.761; held-out-station Brier 0.085 vs climatology 0.093.
Drone law: 14 CFR 107.51 needs 3 statute miles flight visibility and 500 ft below cloud. Fog is cloud on the ground, so launching through a deck is outside the rule; your call, not this tool's.
Sources and fetch times for every number: site/kankakee/data/2026-10-16-*.json.

dashboard · 7-day outlook · raw json