Warmest, Second Wettest December in IL

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Flooded park in Champaign, IL.

Looking at the preliminary numbers, Illinois has experienced its warmest, and second wettest December on record. Statewide records go back to 1895.

Precipitation: the statewide average precipitation was 6.70 inches, 4.01 inches above average and the second wettest December on record.

The wettest December on record was in 1982 with 7.17 inches. Like this year, that was also during a major El Niño event.

Temperature: the statewide average temperature for December is 40.6 degrees, an incredible 10.7 degrees above average and the warmest December on record. This December beat the old record by 1.7 degrees that was set in 1923 with 38.9 degrees.

[this posted was updated on January 2, 2016, to reflect the latest information for December 2015]

Late December Heavy Rains, Flooding in Illinois

A large, slow-moving low-pressure system moved through the central US, bringing widespread, heavy rains to Illinois and neighboring state. This resulted in considerable flooding ranging from flooded basements to major flooding on the Mississippi River.

Rainfall Maps for December 26-29, 2015

This first map shows the widespread heavy rains from Texas, Oklahoma, Arkansas, Missouri, Illinois, Kentucky, and Indiana. Areas in the three shades of red represent amounts of 5 to 10 inches. The purple streak from Oklahoma to Missouri represents 10 to 15 inches of rain.

Southern and central Illinois were hardest hit with large areas of 5 to 10 inches of rain, falling on soils that were already saturated. Meanwhile, the northern third of Illinois received 2 to 4 inches of precipitation (rain plus water content of snow), as well as 1 to 4 inches of snow.

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This second map zooms in on Illinois, showing the heavy rains across the state more clearly. The lightest shade of red is 5 to 6 inches, the next darker shade is 6 to 8 inches, and the darkest shade of red east of St. Louis and south of Decatur is 8 to 10 inches.

To put this in perspective, the average December precipitation for Illinois ranges from 4.5 inches in southern Illinois to 2 inches in northwest Illinois. So areas in central Illinois, where the average is about 3 inches, received about 3 times that over the course of 4 days.

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Flooding

These heavy rains have led to widespread flooding. Here is the NWS map of rivers and streams in various stages of flooding. The purple dots and squares represent areas of major flooding, mostly the Mississippi River from St. Louis southward.

“Major Flooding” means extensive inundation of structures and roads. Significant evacuations of people and property. Red means moderate flooding (some risk of flooding to structures and roads) and tan means minor flooding. 

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Here is a NWS river flood forecast at Chester IL on the Mississippi River, showing the impact of the heavy rains upstream. Right now they are expecting a record, or near record, stage at that point of the river.

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Rainfall Totals for December 26-29, 2015

Here are some rainfall totals from our volunteer CoCoRaHS network around the state, ranked from highest to lowest, with complete data from December 26-29, 2015. Godfrey IL, near St. Louis, reported the highest 4-day total of 10.03 inches.

 

Station
Number
Station Name Total Precip (inches)
 IL-MD-34 Godfrey 2.5 SSW 10.03
 IL-MD-28 Staunton 4.3 SSW 8.90
 IL-SH-1 Shelbyville 0.5 NE 8.87
 IL-MD-10 Granite City 1.4 ENE 8.57
 IL-EF-13 Effingham 6.7 N 7.61
 IL-CN-3 Pana 6.2 NNE 7.45
 IL-MP-12 Carlinville 1.1 E 7.42
 IL-SC-18 Fairmont City 0.9 ENE 7.05
 IL-MY-1 Nokomis 4.5 NW 6.98
 IL-RH-7 Sparta 1.6 SW 6.74
 IL-CN-7 Taylorville 0.6 ENE 6.73
 IL-DG-12 Camargo 4.5 ESE 6.65
 IL-RH-8 Sparta 1.9 SSW 6.56
 IL-SH-3 Mode 3.7 NW 6.51
 IL-ED-6 Chrisman 3.6 ESE 6.50
 IL-DG-11 Tuscola 0.6 NNE 6.27
 IL-MP-18 Girard 0.1 WSW 6.26
 IL-MA-1 Mount Zion 0.8 ESE 6.22
 IL-CN-4 Edinburg 3.0 W 6.15
 IL-CP-21 Broadlands 0.1 SSW 6.13
 IL-DG-4 Tuscola 0.5 WSW 6.10
 IL-MD-20 Edwardsville 0.9 WSW 6.08
 IL-MD-33 Troy 1.5 SSE 6.04
 IL-WM-4 Bush 2.0 ESE 6.02
 IL-MP-4 Girard 1.2 W 5.97
 IL-SC-11 Centreville 1.9 E 5.87
 IL-WS-3 Okawville 2.3 SW 5.76
 IL-CL-2 Marshall 4.6 W 5.75
 IL-PT-1 Monticello 3.5 NNE 5.72
 IL-CP-14 Philo 0.3 NE 5.68
 IL-SC-9 Belleville 4.5 WNW 5.67
 IL-CP-1 Homer 2.0 N 5.63
 IL-SC-3 Belleville 2.2 SE 5.57
 IL-EF-10 Watson 0.3 NE 5.52
 IL-SC-23 Belleville 2.7 SSE 5.52
 IL-MC-1 Belknap 11.1 ESE 5.45
 IL-JF-4 Mount Vernon 1.3 SW 5.44
 IL-CP-58 Urbana 0.9 SSE 5.43
 IL-VR-19 Danville 7.6 N 5.34
 IL-MG-9 Jacksonville 1.2 SW 5.26
 IL-CP-95 Urbana 4.2 ESE 5.15
 IL-VR-4 Henning 3.4 SSE 5.15
 IL-SG-4 Riverton 1.9 W 5.12
 IL-PT-6 Monticello 6.5 WSW 5.11
 IL-CP-31 St. Joseph 0.9 SSW 5.04
 IL-MG-6 Murrayville 0.4 NE 5.03
 IL-CP-90 Champaign 2.4 S 5.02
 IL-VR-20 Westville 0.6 SSW 4.99
 IL-RC-3 Olney 0.7 E 4.95
 IL-PT-8 White Heath 3.7 NNE 4.94
 IL-VR-14 Danville 0.6 NW 4.94
 IL-CP-37 Sidney 0.9 N 4.93
 IL-CP-59 Mahomet 1.7 NNE 4.92
 IL-CP-92 Mahomet 1.2 S 4.90
 IL-MN-5 Odin 0.5 SSE 4.88
 IL-SG-47 Springfield 6.6 S 4.85
 IL-CP-64 Champaign 2.4 SSE 4.83
 IL-PT-13 Mansfield 3.0 WSW 4.83
 IL-SG-17 Springfield 4.4 W 4.83
 IL-CP-81 Dewey 1.6 NNW 4.75
 IL-LG-36 Lincoln 1.7 W 4.71
 IL-CS-3 Arenzville 5.3 NNE 4.68
 IL-ME-10 Athens 2.4 NNW 4.61
 IL-SG-11 Chatham 1.4 ESE 4.56
 IL-MO-4 Fults 3.7 ENE 4.50
 IL-LG-8 Lincoln 1.4 SE 4.46
 IL-ME-9 Athens 1.0 N 4.46
 IL-LG-13 Lincoln 0.9 NNW 4.38
 IL-LG-22 Lincoln 0.87 SE 4.38
 IL-CK-14 Chicago 5.5 ESE 4.36
 IL-MCL-4 Heyworth 0.6 E 4.35
 IL-MCL-7 Le Roy 4.1 SSW 4.31
 IL-LG-9 Beason 4.0 SW 4.27
 IL-PT-17 Monticello 3.8 NNE 4.25
 IL-VR-17 Hoopeston 0.8 W 4.18
 IL-LG-40 Lincoln 0.4 NE 4.17
 IL-CP-47 Champaign 2.3 NNW 4.15
 IL-FK-5 West Frankfort 0.3 WNW 4.02
 IL-LG-30 Atlanta 7.1 W 4.01
 IL-CP-28 Champaign 1.3 SSW 4.00
 IL-MCL-30 Saybrook 4.3 SSE 3.96
 IL-SG-48 Springfield 2.6 WNW 3.92
 IL-FD-9 Gibson 3.0 WNW 3.86
 IL-CW-3 Hutsonville 0.3 WNW 3.79
 IL-LV-6 Pontiac 1.0 SE 3.71
 IL-GY-2 Dwight 4.1 NNW 3.68
 IL-TZ-26 Pekin 3.6 SSE 3.66
 IL-MCL-23 Normal 1.9 ESE 3.53
 IL-KK-7 Kankakee 4.5 WNW 3.44
 IL-KK-23 Bonfield 4.0 WSW 3.40
 IL-SG-44 Sherman 4.1 N 3.40
 IL-KK-25 Bonfield 4.2 NNE 3.39
 IL-MCL-2 Arrowsmith 1.7 NNE 3.25
 IL-WF-12 Germantown Hills 1.3 NW 3.21
 IL-IR-2 Ashkum 5.6 E 3.19
 IL-LV-7 Chatsworth 0.4 ESE 3.19
 IL-WL-23 Beecher 3.4 SSE 3.15
 IL-CK-145 Oak Park 1.5 S 3.14
 IL-MCL-9 Danvers 1.7 WNW 3.14
 IL-WL-26 Manhattan 0.8 ESE 3.14
 IL-GY-12 Braceville 0.5 SSE 3.12
 IL-WL-131 Homer Glen 0.7 NNE 3.12
 IL-GY-9 Mazon 0.5 ENE 3.10
 IL-CK-82 Burnham-Hegewisch 1.6 NNW 3.09
 IL-PR-9 Dunlap 2.6 S 3.09
 IL-WL-73 Wilmington 2.6 SE 3.09
 IL-WL-20 Manhattan 4.7 ENE 3.00
 IL-CK-152 Chicago Ridge 0.2 WSW 2.99
 IL-CK-206 Park Forest 1.0 SW 2.98
 IL-TZ-14 Morton 1.0 SSE 2.97
 IL-WL-63 New Lenox 1.8 SE 2.96
 IL-CK-154 Worth 0.1 E 2.92
 IL-GY-10 Minooka 0.3 NE 2.88
 IL-WL-118 Elwood 4.6 NE 2.84
 IL-GY-1 Carbon Hill 3.1 N 2.83
 IL-WL-97 New Lenox 3.3 E 2.83
 IL-WL-99 Manhattan 1.9 SE 2.83
 IL-GY-21 Coal City 2.8 N 2.82
 IL-MCD-7 Colchester 3.5 NE 2.80
 IL-CK-253 Midlothian 0.1 SSE 2.79
 IL-WL-67 Channahon 2.5 SSE 2.75
 IL-DP-79 Burr Ridge 1.9 SW 2.73
 IL-LS-33 Streator 3.7 ENE 2.73
 IL-WL-16 Homer Glen 0.8 ENE 2.73
 IL-WL-25 Crete 2.6 E 2.72
 IL-HN-1 Dallas City 3.0 SSE 2.71
 IL-KK-26 Kankakee 3.2 SE 2.70
 IL-GY-16 Morris 6.4 ESE 2.68
 IL-LS-1 Ottawa 1.3 NW 2.65
 IL-CK-50 Palos Park 1.3 SW 2.64
 IL-CK-153 Alsip 0.2 E 2.64
 IL-WL-71 Plainfield 1.1 SW 2.62
 IL-CK-196 Harwood Heights 1.9 NNE 2.61
 IL-CK-211 Oak Lawn 1.6 WNW 2.60
 IL-LS-17 Ottawa 1.6 N 2.58
 IL-CR-4 Chadwick 2.7 WSW 2.56
 IL-DP-127 Downers Grove 0.4 NNE 2.55
 IL-WL-100 Joliet 2.9 WNW 2.54
 IL-CK-180 Park Ridge 0.5 SSW 2.50
 IL-DP-85 Villa Park 1.0 NW 2.50
 IL-KD-24 Oswego 5.0 SSE 2.50
 IL-WL-119 Homer Glen 1.6 NW 2.50
 IL-WL-80 Lockport 1.3 SE 2.48
 IL-CK-106 Hoffman Estates 4.6 W 2.45
 IL-LK-42 Gurnee 1.6 W 2.44
 IL-CK-61 Oak Park 1.0 SW 2.42
 IL-DP-57 Aurora 3.5 NE 2.42
 IL-CK-232 Rogers Park 0.6 ESE 2.40
 IL-CK-98 La Grange Park 0.7 SSW 2.37
 IL-DP-102 Bolingbrook 2.7 NE 2.34
 IL-DP-32 Lisle 1.3 SE 2.32
 IL-LS-7 Sheridan 3.4 SSE 2.32
 IL-LS-56 Ottawa 0.4 N 2.32
 IL-DP-77 Roselle 1.1 W 2.31
 IL-GY-20 Morris 2.5 SSE 2.30
 IL-KN-62 Batavia 1.3 WNW 2.29
 IL-KX-9 Knoxville 0.7 NW 2.29
 IL-GY-11 Morris 4.8 NNW 2.27
 IL-LS-57 Mendota 0.4 ENE 2.26
 IL-CK-75 Elk Grove Village 2.2 WSW 2.25
 IL-CK-149 Oak Lawn 0.5 SSW 2.25
 IL-LE-8 Ashton 0.4 SSW 2.22
 IL-DP-132 Wheaton 2.0 NNE 2.19
 IL-HD-1 Stronghurst 0.4 SSW 2.19
 IL-CK-94 Lincolnwood 1.8 E 2.18
 IL-BU-8 Tiskilwa 2.1 N 2.16
 IL-LK-8 Gurnee 2.5 NE 2.15
 IL-LK-22 Lake Forest 2.1 NNE 2.15
 IL-DP-109 Elmhurst 0.8 ESE 2.14
 IL-KN-51 Sugar Grove 1.4 ENE 2.14
 IL-DP-75 Naperville 1.1 NW 2.13
 IL-LS-34 La Salle 0.1 W 2.11
 IL-KN-4 Sugar Grove 0.7 NE 2.10
 IL-CK-63 Elk Grove Village 0.6 ESE 2.09
 IL-DP-101 Aurora 3.8 SE 2.09
 IL-KD-34 Plainfield 4.8 SW 2.09
 IL-LK-39 Riverwoods 0.4 ENE 2.09
 IL-DP-40 Lombard 1.0 NNW 2.08
 IL-KN-33 North Aurora 1.5 NE 2.08
 IL-LK-69 Highwood 0.9 S 2.06
 IL-KN-63 Geneva 1.7 WSW 2.04
 IL-DP-100 Bartlett 1.1 SE 2.00
 IL-WL-46 Peotone 0.4 ENE 1.99
 IL-LS-11 Mendota 0.9 N 1.98
 IL-DK-24 Somonauk 1.9 NE 1.95
 IL-LK-16 Buffalo Grove 1.5 N 1.95
 IL-DP-16 Aurora 3.6 SE 1.94
 IL-WN-26 Rockford 1.5 ENE 1.92
 IL-KN-23 Batavia 1.5 WNW 1.91
 IL-KN-30 Elburn 0.4 NW 1.90
 IL-KN-64 St. Charles 0.1 E 1.84
 IL-KN-9 Elgin 1.0 S 1.82
 IL-WN-8 Rockford 0.7 NW 1.82
 IL-BN-14 Capron 0.1 N 1.78
 IL-KN-110 Elgin 1.9 NE 1.78
 IL-LE-21 Dixon 5.2 WSW 1.74
 IL-LK-3 Beach Park 1.4 W 1.69
 IL-MCH-43 Algonquin 0.7 N 1.69
 IL-MCH-30 Wonder Lake 0.8 WNW 1.66
 IL-LK-81 Lake Villa 2.3 WSW 1.63
 IL-CK-131 Schaumburg 2.0 E 1.62
 IL-KN-95 Elgin 2.5 W 1.53
 IL-WN-3 Machesney Park 3.1 ENE 1.51
 IL-CR-12 Mount Carroll 6.8 NNW 1.47
 IL-RI-13 Moline 0.7 NNE 1.44
 IL-WN-2 Roscoe 1.6 ESE 1.44
 IL-SP-6 Freeport 2.0 NW 1.43
 IL-RI-3 Moline 0.9 N 1.41
 IL-CK-192 Park Ridge 0.7 WNW 1.38
 IL-SP-7 Davis 0.5 N 1.38
 IL-LE-17 Dixon 1.5 SW 1.32
 IL-OG-4 Byron 3.2 N 1.23
 IL-CR-13 Shannon 0.2 S 1.22
 IL-MCH-66 Harvard 2.8 SSE 1.02
 IL-CK-36 Chicago 4.7 NE 1.01
 IL-SP-8 Winslow 4.3 ESE 0.77
 IL-LE-14 Amboy 0.5 ESE 0.17

Heavy Rains Hit Illinois

A large, slow-moving winter storm has dropped considerable rainfall across Illinois in the last few days. Here is the map of the amounts in the last 7 days, through this morning (12/28). Areas in shades of red are 5 to 8 inches, and follow Interstate 70 across Illinois. Areas in shades of yellow to light brown are 2 to 5 inches. I’ll post more when the rain finally ends.

AHPS Precipitation Analysis

And it’s still raining. There is the potential for another 0.75 to 1.25 inches expected in southern and central Illinois. Another 1.25 to 1.75 inches is expected in parts of northern and western Illinois before this system moves on.

Is this El Niño?

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Warm, Nearly Snowless December in Illinois

The first 17 days of December in Illinois has been nearly 11 degrees above average, with plenty of rain and a little snow in northern Illinois.

Temperature

Here are the temperature departures for December 1-17. The statewide average temperature was 43.0 degrees, 10.8 degrees above average. The light to dark pink in southern and central Illinois represents a 9 to 11 degree departure from average. The shades of red north of Interstate 72 represent an 11 to 13 degree departure from average. The departures get even stronger in Iowa, Minnesota, and Wisconsin.

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Snow

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Latest Seasonal Outlook for IL

Illinois has higher odds of being both warmer and drier than average though June, according to the newly released NWS Climate Prediction Center outlooks.

The main driver of the forecast continues to be the strong El Niño event in the Pacific Ocean. El Niño is expected to go away by late spring or early summer. The increased odds of drier conditions through June could be a concern. However, I am more confident in the temperature forecasts from CPC than I am of the precipitation forecasts.

January:

(click on any map to make it bigger)
Illinois has higher odds of being both warmer and drier than average.

January – March:

Illinois has higher odds of being both warmer and drier than average.

April – June:

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