New Weather Outlook for June

The NWS Climate Prediction Center released their updated outlook for June, 2015. The new June outlook shows northern Illinois, including the Chicago area, with an increased chance of warmer and drier than average conditions.

Much of central and southern Illinois has equal chances (EC) of above, below, and near-average temperature and precipitation. This is different from the previous outlook for June that was released mid-May. That one had central and southern Illinois with an increased chance of wetter than average conditions.

While these outlooks cover the entire month, most of the model forecast skill is in the first 10 days. So the features of warmer and drier conditions in northern Illinois may be more in line with what’s expected in the first week or two and less with the entire month.  More useful information can be obtained from the NWS 6-10 and 8-14 day forecasts which are updated daily.

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Temperature forecast for June. Click to enlarge.
off15_prcp
Precipitation forecast for June. Click to enlarge.
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February – 7th Coldest on Record for Illinois

The statewide average temperature for February was 18.6 degrees. That is 12.3 degrees below the 1981-2010 average and the 7th coldest February on record. By comparison, February 2014 was 9th coldest at 19.5 degrees.

Here are some amazing statistics for Chicago. February was tied with 1875 for the coldest on record, according to the Chicago National Weather Service.  The average temperature for February was 14.6 degrees, 13.1 degrees below average. In addition, it was the 10th coldest month overall on record. February snowfall in Chicago was the third largest on record with 26.8 inches, 17.7 inches above average.

Snowfall for February in Illinois was widespread and well above average. Amounts of 15 to 20 inches were common in western and northern Illinois and 10 to 15 across central Illinois and parts of far southern Illinois. This was 8 to 12 inches above average in many locations. See maps below. Click to enlarge.

Some other February snowfall totals from around the state:

  • Chicago Midway AP: 28.3 inches
  • Rockford: 14.7 inches
  • Peoria: 12.8 inches
  • Quincy Lock and Dam: 11.2 inches
  • Springfield: 22.6 inches
  • Champaign-Urbana: 12.4 inches
  • Bloomington-Normal: 13.0 inches
  • Carbondale: 6.0 inches

The statewide average precipitation (rain plus the water content of snow) for February was 1.5 inches, 0.5 inches below average. Most of the state received 1 to 2 inches of precipitation, except for far southern Illinois which got 2 to 3 inches. See the second batch of maps for precipitation and precipitation departures from average.

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Quiet Winter for Snowfall across central US

Snowfall across the central US has been slightly below average so far this winter and stands in stark contrast to last winter. However, the impact on soil moisture, rivers, and streams has been minimal.

Here is an example of snowfall differences. At Chicago O’Hare airport the snowfall total for this winter through January 14 is 13.7 inches. Last year through this date it was 35.0 inches and the 1981-2010 average is 14.2 inches.

In the first map are the snowfall departures for this winter. All the areas in tan or beige are up to 10 inches below average. That includes almost all of Illinois, Minnesota, Iowa, Missouri, Indiana, and Kentucky, as well as large portions of the Dakotas, Nebraska, Kansas, Wisconsin, Michigan, and Ohio. Areas in green are above average and include a small area in far southern Illinois and another around Moline. Snowfall is above average across upper Wisconsin and the Michigan UP.  Continue reading

Friday Wrapup – Illinois Very Cold and Dry in November

snow-nov21So far, November has been much colder and drier than average. The statewide average temperature is 34.6 degrees, which is 9 degrees below average.

The statewide average precipitation (rainfall + water content of snow) was only 0.6 inches, about a third of the average through this date.

There have been astounding snowfall totals in places like Buffalo, NY, and some significant snowfall in Minnesota and Wisconsin. However, Illinois and most of the surrounding states have had far less snowfall (first map) in November. Many sites in the state had 1 to 2 inches except for a stretch between Quincy and Chicago with less than an inch.

The modest snowfall totals in November so far are not that unusual. Average snowfall totals for the month are generally less than an inch south of I-80 and about 1 to 2 inches north of I-80 (second map).

map2Illinois-snow-11NOV-normals

First Snow in Illinois

Traces of snow were reported in Chicago and Rockford on October 4. A few years ago I did a post on the earliest and median dates for the first measurable snowfall of the season. Measurable means at least 0.1 inches or more.  Snow flurries or traces of snow do not count since they have not been tracked closely in the historical weather records.

No real surprises for anyone who has experienced winter in Illinois. The earliest dates of measurable snow are in the late October, early November time frame. And the median dates range from late November in northern Illinois to the second half of December in southern Illinois. Even so, the dates can vary considerably between nearby sites since many of the early season snows are sporadic and not very widespread.

firstsnow-earliest-stn-Illinois

The median is also known as the 50th percentile and represents in the “middle” of the distribution of dates. In many cases it is a better measure than the average, which can be thrown off by some date that is extraordinarily early or late.

These maps are based on sites that reported snowfall regularly since 1981. The dates are the earliest and median dates of the first measurable snow (0.1 inches or more) for the standard averaging period of 1981 to 2010 (also known as “normal”).

firstsnow-median-stn-Illinois

Illinois State Climatologist

The other night we had a brief period of snow with no accumulation on the ground here in Champaign. However I did see some on my car for a few minutes (see right) before it melted. That reminded me that Zoe and I had worked on some “first snowfall” maps. These maps are based on sites that reported snowfall regularly since 1981. The dates are the earliest and median dates of the first measurable snow (0.1 inches or more) for the standard averaging period of 1981 to 2010 (also known as “normal”).

No real surprises for anyone who has experienced winter in Illinois. The earliest dates are in the late October, early November time frame. And the median dates range from late November in northern Illinois to the second half of December in southern Illinois. Even so, the dates can vary considerably between nearby sites since many of the early season…

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When Is Fall? Astronomical, Meteorological, Climatological?

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The Quad – University of Illinois in fall color.

No doubt today (September 22) will be announced as the “first day of fall” because of the fall or autumnal equinox. However, that concept refers to the date when we get equal amounts of daylight and dark.  I don’t think it was ever intended that this astronomical event would be the start of fall. In fact, this equinox would be the start of spring in the southern hemisphere. So to be fair to everyone we should call it the September equinox and leave fall out of it.  😉

Climatologists and meteorologists prefer to use calendar months to define the four seasons in the US. For example, fall would start September 1 and end on November 30. Not only is this more convenient, because you can use monthly data, but it lines up better with the typical or average temperature pattern for Illinois. Unfortunately, the meteorologists would describe this three-month period as “meteorological fall”. However, I would argue it is “climatological fall” since we are looking at long-term average to determine the season.

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Chicago Gets Soaked Again

Heavy rains fell across the Chicago metropolitan area again today (August 22, 2014). Here is the map of rainfall amounts from our volunteer CoCoRaHS network. You will get a slightly larger and more clear image if you click on the map below. Many sites in the orange have received the average August rainfall in just 1 day. The largest total so far is from an observer in Bloomingdale in DuPage County with 5.45 inches.

august22
Click to enlarge.

Here are the reports for the morning of August 22, 2014, ranked from high to low. Most observers report between 7 and 8 am.

Station ID Station Name Total Precip (inches)
 IL-DP-72 Bloomingdale 0.9 NNE 5.45
 IL-CK-12 Bridgeview 1.3 NNW 4.86
 IL-GY-2 Dwight 4.1 NNW 4.82
 IL-LE-18 Sublette 0.1 NNE 4.78
 IL-CK-88 Countryside 0.8 ENE 4.69
 IL-CK-211 Oak Lawn 1.6 WNW 4.68
 IL-LS-36 Marseilles 2.8 NW 4.67
 IL-CK-152 Chicago Ridge 0.2 WSW 4.51
 IL-DP-77 Roselle 1.1 W 4.46
 IL-CK-149 Oak Lawn 0.5 SSW 4.41
 IL-CK-154 Worth 0.1 E 4.29
 IL-GY-19 South Wilmington 0.3 WNW 4.15
 IL-DP-109 Elmhurst 0.8 ESE 4.10
 IL-LS-25 Marseilles 5.6 WNW 4.10
 IL-DP-14 Westmont 1.2 SSE 4.05
 IL-KK-23 Bonfield 4.0 WSW 3.92
 IL-CK-148 Oak Lawn 1.9 SE 3.73
 IL-KN-11 St Charles 1.1 SW 3.70
 IL-LV-14 Odell 4.4 SE 3.70
 IL-CK-75 Elk Grove Village 2.2 WSW 3.69
 IL-CK-98 La Grange Park 0.7 SSW 3.64
 IL-CK-187 North Riverside 0.4 W 3.61
 IL-CK-145 Oak Park 1.5 S 3.59
 IL-DP-117 Elmhurst 2.0 SE 3.57
 IL-DP-38 Elmhurst 0.4 SW 3.55
 IL-CK-63 Elk Grove Village 0.6 ESE 3.52
 IL-KN-50 Elburn 2.7 NNE 3.48
 IL-CK-131 Schaumburg 2.0 E 3.45
 IL-DP-100 Bartlett 1.1 SE 3.35
 IL-LS-47 Earlville 7.6 SSE 3.35
 IL-KN-30 Elburn 0.4 NW 3.32
 IL-LS-50 Seneca 1.2 NNE 3.30
 IL-CK-82 Burnham-Hegewisch 1.6 NNW 3.19
 IL-LS-45 Streator 1.3 WSW 3.19
 IL-KN-63 Geneva 1.7 WSW 3.15
 IL-DP-85 Villa Park 1.0 NW 3.13
 IL-CK-61 Oak Park 1.0 SW 3.11
 IL-WF-19 Washburn 5.2 W 3.10
 IL-DP-29 Glen Ellyn 1.6 SSE 3.02
 IL-LS-51 Seneca 1.1 NNE 3.00
 IL-LV-17 Emington 2.2 SSE 3.00
 IL-LV-12 Streator 1.4 S 2.99
 IL-KN-62 Batavia 1.3 WNW 2.97
 IL-KN-58 Lily Lake 2.1 E 2.95
 IL-CK-202 River Forest 0.9 SSE 2.93
 IL-GY-9 Mazon 0.5 ENE 2.88
 IL-CK-240 Chicago 2.7 WNW 2.87
 IL-DP-79 Burr Ridge 1.9 SW 2.87
 IL-LS-17 Ottawa 1.6 N 2.82
 IL-CK-129 Schaumburg 2.7 WSW 2.81
 IL-KN-8 Geneva 3.3 WSW 2.81
 IL-LS-1 Ottawa 1.3 NW 2.78
 IL-DP-18 Downers Grove 2.1 SE 2.66
 IL-DP-40 Lombard 1.0 NNW 2.62
 IL-DP-98 Downers Grove 0.9 S 2.60
 IL-CK-192 Park Ridge 0.7 WNW 2.57
 IL-GY-12 Braceville 0.5 SSE 2.54
 IL-DP-63 Bartlett 1.0 SSE 2.51
 IL-KN-5 Batavia 0.7 WSW 2.44
 IL-CK-153 Alsip 0.2 E 2.42
 IL-CK-238 Elmwood Park 0.7 NNW 2.42
 IL-LS-49 North Utica 6.3 N 2.35
 IL-KN-78 Geneva 1.3 SSW 2.34
 IL-KN-104 Geneva 3.9 WSW 2.33
 IL-LE-14 Amboy 0.5 ESE 2.33
 IL-KN-79 Geneva 1.6 WSW 2.23
 IL-DP-49 Naperville 2.5 ESE 2.22
 IL-CK-180 Park Ridge 0.5 SSW 2.21
 IL-DP-32 Lisle 1.3 SE 2.16
 IL-CK-178 Rolling Meadows 0.9 ESE 2.15
 IL-DP-122 Clarendon Hills 0.5 NW 2.14
 IL-LS-39 Ottawa 0.5 NNW 2.14
 IL-KN-67 St. Charles 6.0 NW 2.13
 IL-KN-33 North Aurora 1.5 NE 2.12
 IL-KN-64 St. Charles 0.1 E 2.12
 IL-DK-21 De Kalb 0.6 SE 2.09
 IL-DP-118 Darien 0.4 SSE 2.09
 IL-DP-83 Lombard 1.2 NNW 2.05
 IL-CK-74 Oak Park 1.3 NNE 2.04
 IL-MCH-49 Cary 0.3 NE 2.04
 IL-DP-96 Lombard 1.0 WSW 2.02
 IL-LS-27 Oglesby 0.6 ESE 1.94
 IL-WF-12 Germantown Hills 1.3 NW 1.93
 IL-CK-121 Palatine 1.3 E 1.92
 IL-LS-34 La Salle 0.1 W 1.90
 IL-LV-7 Chatsworth 0.4 ESE 1.85
 IL-DK-10 Malta 0.4 SSE 1.84
 IL-CK-81 Arlington Heights 1.8 NNW 1.83
 IL-DP-42 Carol Stream 0.3 SSE 1.83
 IL-DP-69 Glen Ellyn 1.0 NE 1.81
 IL-DP-16 Aurora 3.6 SE 1.80
 IL-CK-107 Evanston 1.4 N 1.79
 IL-LS-2 Oglesby 0.4 N 1.79
 IL-CK-14 Chicago 5.5 ESE 1.78
 IL-CK-243 Elmwood Park 0.7 ESE 1.77
 IL-LS-12 Peru 0.6 SW 1.76
 IL-CK-32 Chicago 6.4 NNE 1.75
 IL-CK-175 Winnetka 1.2 S 1.75
 IL-WL-118 Elwood 4.6 NE 1.72
 IL-CK-235 Park Ridge 1.1 ENE 1.70
 IL-DP-101 Aurora 3.8 SE 1.66
 IL-PR-9 Dunlap 2.6 S 1.57
 IL-CK-106 Hoffman Estates 4.6 W 1.56
 IL-LS-46 Mendota 2.4 SE 1.56
 IL-KN-9 Elgin 1.0 S 1.54
 IL-KN-95 Elgin 2.5 W 1.53
 IL-IR-10 Buckley 0.2 SSE 1.52
 IL-CK-168 Ravenswood Manor 0.1 ESE 1.49
 IL-WL-119 Homer Glen 1.6 NW 1.47
 IL-DP-27 Naperville 2.1 ESE 1.45
 IL-WL-46 Peotone 0.4 ENE 1.45
 IL-KN-2 Elgin 2.3 WNW 1.39
 IL-WL-67 Channahon 2.5 SSE 1.38
 IL-KD-23 Montgomery 1.7 SSE 1.37
 IL-LV-10 Pontiac 0.7 ESE 1.37
 IL-WL-61 Channahon 0.8 NNE 1.37
 IL-WL-71 Plainfield 1.1 SW 1.37
 IL-CK-50 Palos Park 1.3 SW 1.35
 IL-KN-51 Sugar Grove 1.4 ENE 1.32
 IL-WL-25 Crete 2.6 E 1.32
 IL-WL-41 Peotone 0.5 ENE 1.32
 IL-LV-6 Pontiac 1.0 SE 1.31
 IL-MCH-43 Algonquin 0.7 N 1.31
 IL-KD-34 Plainfield 4.8 SW 1.30
 IL-WL-84 Beecher 3.4 ENE 1.30
 IL-WL-99 Manhattan 1.9 SE 1.29
 IL-DP-102 Bolingbrook 2.7 NE 1.28
 IL-WL-20 Manhattan 4.7 ENE 1.28
 IL-WL-79 Peotone 0.5 SE 1.27
 IL-CK-215 Glenview 0.9 SW 1.26
 IL-WL-93 New Lenox 4.2 SE 1.26
 IL-GY-20 Morris 2.5 SSE 1.25
 IL-WL-121 Monee 4.9 W 1.25
 IL-WN-19 Rockton 1.0 ESE 1.24
 IL-WL-36 Homer Glen 3.9 WNW 1.22
 IL-CK-206 Park Forest 1.0 SW 1.21
 IL-KN-107 South Elgin 0.9 WSW 1.20
 IL-SP-7 Davis 0.5 N 1.17
 IL-LK-39 Riverwoods 0.4 ENE 1.14
 IL-WL-104 Plainfield 2.7 SE 1.14
 IL-LK-25 Lincolnshire 1.3 WSW 1.13
 IL-KD-46 Oswego 1.0 SW 1.10
 IL-SP-18 Freeport 0.9 ESE 1.10
 IL-WL-16 Homer Glen 0.8 ENE 1.07
 IL-WL-51 Plainfield 2.4 SSE 1.06
 IL-FD-9 Gibson 3.0 WNW 1.05
 IL-WL-80 Lockport 1.3 SE 1.05
 IL-WL-100 Joliet 2.9 WNW 1.05
 IL-KD-5 Montgomery 0.8 SSE 1.04
 IL-WL-120 Joliet 1.2 W 1.04
 IL-KX-11 Galesburg 8.8 S 1.03
 IL-WL-82 Orland Park 4.6 WNW 1.03
 IL-HY-6 New Windsor 2.0 N 1.02
 IL-LK-16 Buffalo Grove 1.5 N 1.02
 IL-WL-64 Joliet 2.3 WNW 1.02
 IL-GY-10 Minooka 0.3 NE 1.01
 IL-CK-146 Glenwood 1.5 ESE 1.00
 IL-KN-82 Batavia 0.8 S 1.00
 IL-LS-7 Sheridan 3.4 SSE 1.00
 IL-LK-69 Highwood 0.9 S 0.99
 IL-CK-53 Glencoe 0.1 NW 0.98
 IL-CK-94 Lincolnwood 1.8 E 0.98
 IL-MCH-66 Harvard 2.8 SSE 0.97
 IL-FL-9 London Mills 1.4 SE 0.95
 IL-WL-111 New Lenox 1.0 NE 0.95
 IL-WF-14 El Paso 5.2 NNW 0.95
 IL-KX-9 Knoxville 0.7 NW 0.93
 IL-MCH-13 Bull Valley 2.5 WNW 0.92
 IL-KK-25 Bonfield 4.2 NNE 0.91
 IL-WL-50 Lockport 3.3 ESE 0.91
 IL-KD-24 Oswego 5.0 SSE 0.90
 IL-KN-91 Hampshire 0.7 W 0.89
 IL-DP-57 Aurora 3.5 NE 0.88
 IL-GY-4 Coal City 0.4 N 0.87
 IL-GY-16 Morris 6.4 ESE 0.87
 IL-WL-73 Wilmington 2.6 SE 0.86
 IL-MCH-61 Woodstock 1.5 WSW 0.84
 IL-WL-97 New Lenox 3.3 E 0.84
 IL-LK-11 Lincolnshire 0.9 N 0.83
 IL-GY-21 Coal City 2.8 N 0.82
 IL-WL-103 Joliet 1.8 NNE 0.80
 IL-CK-42 Mount Prospect 3.0 NE 0.79
 IL-LK-53 Lakemoor 1.5 SE 0.78
 IL-WL-108 Plainfield 4.1 NW 0.78
 IL-LK-15 Bannockburn 0.5 ESE 0.77
 IL-TZ-14 Morton 1.0 SSE 0.77
 IL-KK-28 Chebanse 0.4 NNE 0.76
 IL-WL-123 Bolingbrook 1.4 W 0.76
 IL-CK-232 Lincolnwood 3.2 E 0.75
 IL-GY-1 Carbon Hill 3.1 N 0.75
 IL-LV-4 Chenoa 3.9 NNW 0.75
 IL-TZ-1 Morton 1.0 S 0.74
 IL-WN-30 Pecatonica 2.3 S 0.74
 IL-KN-86 Elgin 7.5 WSW 0.72
 IL-LK-9 Lake Villa 1.1 SSW 0.72
 IL-LE-8 Ashton 0.4 SSW 0.71
 IL-LK-74 Mundelein 1.6 WNW 0.70
 IL-WL-72 New Lenox 2.9 ENE 0.69
 IL-LK-22 Lake Forest 2.1 NNE 0.68
 IL-MCD-5 Macomb 0.6 WNW 0.68
 IL-LK-70 Fox Lake 2.4 SE 0.67
 IL-WL-105 Plainfield 2.9 NNW 0.65
 IL-DP-75 Naperville 1.1 NW 0.64
 IL-MCH-59 Harvard 0.3 E 0.64
 IL-SP-6 Freeport 2.0 NW 0.64
 IL-WN-2 Roscoe 1.6 ESE 0.64
 IL-LK-54 Mundelein 0.5 NNE 0.62
 IL-MR-4 Aledo 0.4 NE 0.62
 IL-LK-86 Mundelein 1.8 NW 0.60
 IL-LK-13 Lake Bluff 1.3 W 0.59
 IL-MCL-2 Arrowsmith 1.7 NNE 0.59
 IL-MR-6 Aledo 0.4 NE 0.59
 IL-BU-8 Tiskilwa 2.1 N 0.58
 IL-DK-17 De Kalb 1.8 NNE 0.58
 IL-BN-14 Capron 0.1 N 0.57
 IL-KK-26 Kankakee 3.2 SE 0.55
 IL-CK-197 Orland Hills 0.6 SE 0.53
 IL-LK-42 Gurnee 1.6 W 0.53
 IL-LK-83 Antioch 3.4 WSW 0.53
 IL-WD-5 Morrison 3.2 E 0.53
 IL-LK-29 Lake Bluff 1.4 W 0.51
 IL-SP-8 Winslow 4.3 ESE 0.51
 IL-WD-14 Sterling 4.9 WSW 0.51
 IL-WL-63 New Lenox 1.8 SE 0.51
 IL-MCL-9 Danvers 1.7 WNW 0.50
 IL-SP-14 Freeport 1.7 ESE 0.50
 IL-DK-5 Cortland 0.3 SSW 0.49
 IL-MCH-33 Woodstock 3.8 SW 0.48
 IL-MCH-52 Woodstock 0.8 SSW 0.47
 IL-LK-3 Beach Park 1.4 W 0.45
 IL-LK-19 Waukegan 2.2 N 0.45
 IL-TZ-10 Tremont 3.6 E 0.45
 IL-LK-72 Wadsworth 1.4 SSE 0.44
 IL-MCL-23 Normal 1.9 ESE 0.44
 IL-IR-14 Watseka 6.9 WNW 0.43
 IL-OG-4 Byron 3.2 N 0.43
 IL-WN-14 Rockford 3.3 NE 0.43
 IL-BU-5 Princeton 1.1 SE 0.42
 IL-BU-9 La Moille 0.2 NNE 0.42
 IL-CK-64 Homewood 0.1 ESE 0.42
 IL-LK-8 Gurnee 2.5 NE 0.42
 IL-LK-84 Waukegan 1.7 E 0.40
 IL-LE-10 Dixon 3.0 NNW 0.39
 IL-WF-18 El Paso 6.2 SW 0.39
 IL-CK-170 Flossmoor 0.5 SW 0.38
 IL-HY-1 Orion 4.1 NW 0.38
 IL-MCL-18 Bloomington 3.2 NE 0.36
 IL-LE-5 Sterling 4.3 NE 0.35
 IL-MCL-17 Bloomington 2.7 NE 0.35
 IL-CR-11 Milledgeville 0.4 ESE 0.34
 IL-DP-78 Naperville 2.4 SE 0.34
 IL-MCL-32 Danvers 0.34
 IL-WN-8 Rockford 0.7 NW 0.34
 IL-KD-12 Yorkville 1.1 W 0.33
 IL-WL-113 New Lenox 2.1 SE 0.33
 IL-KK-34 Bradley 1.1 SW 0.32
 IL-WD-8 Coleta 1.4 SSW 0.32
 IL-IR-2 Ashkum 5.6 E 0.31
 IL-RI-10 Moline 1.1 N 0.31
 IL-CP-81 Dewey 1.6 NNW 0.30
 IL-LK-23 Winthrop Harbor 0.2 SSE 0.30
 IL-SP-17 Pearl City 0.4 SW 0.30
 IL-KK-22 Bourbonnais 1.5 NNE 0.29
 IL-KD-25 Yorkville 1.8 SSE 0.27
 IL-LK-27 Winthrop Harbor 0.7 SSW 0.27
 IL-LE-17 Dixon 1.5 SW 0.27
 IL-RI-3 Moline 0.9 N 0.27
 IL-RI-13 Moline 0.7 NNE 0.26
 IL-CR-12 Mount Carroll 6.8 NNW 0.25
 IL-HY-4 Atkinson 2.6 NNE 0.25
 IL-HY-8 Geneseo 2.0 NW 0.25
 IL-LG-32 Lincoln 2.7 NNE 0.22
 IL-OG-12 Davis Junction 1.1 SW 0.22
 IL-KD-7 Plano 0.4 NNE 0.20
 IL-WN-26 Rockford 1.5 ENE 0.20
 IL-KK-35 Bourbonnais 2.9 E 0.19
 IL-MCD-7 Colchester 3.5 NE 0.19