November 2024 Overview
November was warm and wet in Illinois.
Temperatures averaged 46.9 degrees in November (Figure 1), 4.7 degrees above the 30-year normal and tied for the 7th warmest on record statewide.
Precipitation statewide in November was 3.98 inches (Figure 1), 0.9 inches above the 30-year normal, the 23rd wettest November on record statewide and the wettest November since 2015.
Mean streamflow statewide was above the median for the month.
Mean provisional streamflow aggregated statewide was above the long-term median flow for November, about 125% of median (Figure 1). Monthly mean discharge values in November ranged mostly from below normal to above normal for November.
Water surface levels at the end of November were below the full pool or target level at 8 of 18 reporting reservoirs. At the end of November, Lake Shelbyville was 0.4 feet above the December 1 target level, Carlyle Lake level was 0.1 foot above the December 1 target level, and Rend Lake was 0.6 feet above the spillway level.
Lake Michigan’s mean level was below its long-term mean for the month.
Shallow groundwater levels were 0.67 feet below the long-term average at the end of November (Figure 1). Levels averaged 1.17 feet above October and 2.78 feet above last year.
Weather/Climate Information (Trent Ford)
The following description of temperatures, precipitation, severe weather, and drought comes from data compiled by networks that report to the National Oceanic and Atmospheric Administration (NOAA). These data are provisional and may change slightly over time.
November in Illinois was much warmer and wetter than normal statewide. Climatological fall was warmer and drier than normal statewide.
Temperatures averaged 46.9 degrees in November, 4.7 degrees above the 30-year normal and tied for the 7th warmest on record statewide. November temperatures ranged from the low 40s in northern Illinois to the mid-50s in southern Illinois, around 2 to 7 degrees above normal (Figure 2, Table 1a). Several places saw high temperatures into the high 70s in early to mid-November, including 79 degrees in Decatur and Marseilles. Meanwhile, the last week of the month brought some very low temperatures, including 7 degrees in Stockton and 9 degrees in DeKalb. The coldest point in the state last month was Stockton at 41.2 degrees, and the warmest point was Du Quoin at 53.3 degrees. Altogether, 12 daily high maximum temperature records and 4 daily high minimum temperature records were broken in November. The cooler start and end to November broke 11 daily low maximum temperature records and 11 daily low minimum temperature records in Illinois.
Precipitation statewide in November was 3.98 inches, 0.9 inches above the 30-year normal, the 23rd wettest November on record statewide and the wettest November since 2015. September and October were both very dry months across Illinois, outside of the few places that saw rain from the remnants of hurricane Helene. November flipped that script and brought quite a bit of rain across much of the state. November totals ranged from over 8 inches in the St. Louis Metro East area to around 3 inches in north-central Illinois. Parts of southwest and central Illinois were 5 to 8 inches wetter than normal last month, while much of far southern Illinois was 1 to 2 inches drier than normal (Figure 3, Table 1b). Some of the more impressive November totals include 9.97 inches in Granite City and 8.38 inches in Cahokia Heights. Meanwhile, Moline and Rockford only picked up around 2 inches total for the month. Last month was the wettest November on record in Edwardsville with 9.97 inches, and it was the first November since 1946 with over 9 inches of rain in Edwardsville.
Snow: Snowfall in November is not a rare occurrence, but certainly is not a mainstay in Illinois. This year, the northeast corner of the state was the big “winner” for pre-Thanksgiving snowfall, with lake-enhanced snow contributing to widespread 1.5 to 3 inch totals across the Chicagoland area last month. The Interstate 64 corridor also picked up between a quarter and half an inch of snow in the final week of November. Otherwise, the three months comprising climatological fall (September through November) were snow free. Fall snowfall deficits ranged from near 3 inches below normal in northwest Illinois to less than half an inch below normal in the St. Louis Metro East area.
Fall: Climatological fall (September – November) average temperatures ranged from the mid-50s in northern Illinois to the low 60s in southern Illinois, between 2 and 5 degrees above normal (Table 1b). It was a top 10 warmest fall on record in most parts of the state, including the third warmest fall on record in Chicago, the fourth warmest on record in Peoria, and the fifth warmest on record in Champaign-Urbana. Champaign had only nine nights with minimum temperatures below freezing, which was the fewest since 1973 and the fourth fewest on record. The statewide average temperature in fall was 58.2 degrees, 3.6 degrees above the 1991-2020 normal and the third warmest fall on record in Illinois. With only 7.46 inches of average total precipitation, last season was 2.23 inches drier than normal and was the 40th driest fall on record statewide. It was also a top 10 driest fall on record in Freeport (4.47 inches), Moline (3.77 inches), and Galesburg (4.52 inches).
Illinois Climate Network (ICN) (Jennie Atkins)
The Illinois Climate Network (ICN) consists of 19 stations across the state which collects hourly weather and soil information.
Winds averaged 7.5 mph in November, 1.6 mph higher than October but 0.3 mph lower than the network’s long-term average. ICN Monmouth (Warren County) had a monthly average of 12.4 mph, the month’s highest. Monmouth also recorded the highest wind gust, measuring 45.7 mph on November 18.
Temperatures fell 11° from October to an average of 47°. 5° warmer than the long-term average. Station highs were in the high 70s to the mid-60s with lows from the single digits to the mid-20s. The month’s highest temperature was 77°, recorded at ICN Dixon Springs (Pope County) on November 3. The lowest was 9°, measured on November 30 at ICN Freeport (Stephenson County).
Soil temperatures fell 8 to 12° to averages in the high 40s to mid-50s. Under bare soils, temperatures ranged from 23 to 73° at 2 inches and 28 to 75° at 4 inches. Temperatures under sod ranged from 35 to 67° at 4 inches and 37 to 77° at 8 inches.
Precipitation increased across the network in November with all stations surpassing their October totals. Overall stations averaged 4.13 inches, 1.22 inches higher than the long-term average. More than half the month’s total, 2.30 inches, fell in just two days, November 4 and 5.
ICN Springfield (Sangamon County) received 5.10 inches on those two days and a total of 7.77 inches for November, the highest for the month. Three other central stations also had totals greater than 5 inches. However there were drier conditions in the south where three stations, ICN Carbondale (Jackson County), ICN Fairfield (Wayne County), and ICN Rend Lake (Jefferson County), had monthly totals below their long-term averages.
Surface Water Information (Bill Saylor)
Provisional monthly mean flows for this month for 26 streamgaging stations located throughout Illinois are shown in Table 2, compared to statistics of past record of monthly mean flows at those stations for the same month. Both recent and long-term data are retrieved from USGS online data services following the end of the month. Years of record values in Table 2 represent the number of past monthly values included in the Table 2 statistics; at some stations, the available record may not be continuous. Additional source data may be available from USGS.
The statewide percent of historical mean flow and percent of historical median flow are calculated by dividing the sum of the average flows this month at stations in Table 2 by the sum of the historical mean and median flows calculated for the month, respectively, at the same stations. This method is intended to weight individual observations proportionately in the aggregate comparison. (The Illinois River and Rock River stations are excluded from the statewide calculation because other rivers listed in Table 2 contribute to their flow.)
Mean provisional flow aggregated statewide, using the available monthly mean data shown this month in Table 2, was above the median value for November (approximately 125 percent of the median) and below the mean for November (approximately 70 percent of the mean). Monthly mean discharge values in November ranged mostly from below normal to above normal.
Water-Supply Lakes and Major Reservoirs. Table 3 lists selected reservoirs in Illinois, their normal pool or target water surface elevation, and data related to observed variations in water surface elevations. Reservoir levels are obtained from a network of cooperating reservoir operators who report water levels each month. Current reservoir levels reported in Table 3 are representative of the end of the reported month and are presented as the difference in feet from seasonal target level or from full pool, as applies. Years of record represent the number of past reports for the same month used to calculate the average of the month-end values presented in Table 3. For some reservoirs, this average does not include additional period of record prior to a substantial change in reservoir operation. Most reservoirs in Table 3 serve as public water supplies, with the exceptions noted in the last column.
Compared to end-of-October water levels at 18 reservoirs for which levels were reported last month and this month, reported end-of-November water levels were lower at 2 reservoirs, higher at 12 reservoirs, and about the same as at the end of October at 4 reservoirs. For the 18 reservoirs with measurements reported for the end of November, water levels were below normal target pool or spillway level at 8 reservoirs, above normal target pool or spillway level at 6 reservoirs, and at about the target level or spillway level at 4 reservoirs.
Major Reservoirs. Compared to water levels at the end of October, at the end of November the water level at Lake Shelbyville was 1.9 feet higher, Carlyle Lake was 0.8 feet higher, and Rend Lake was at about the same level as a month prior. At the end of November, Lake Shelbyville was 0.4 feet above the December 1 target level, Carlyle Lake level was 0.1 foot above the December 1 target level, and Rend Lake was 0.6 feet above the spillway level.
Great Lakes. Current month mean and end-of-month values are provisional and are relative to International Great Lakes Datum 1985. The November 2024 mean level for Lake Michigan was 578.5 feet. The monthly mean level one year ago (November 2023) was 579.1 feet. The long-term average lake level for November is 578.8 feet, based on 1918-2023 data. In this period of record, the lowest mean level for Lake Michigan for November occurred in 1964 at 576.3 feet, and the highest mean level for November occurred in 1986 at 582.0 feet. The month-end level of Lake Michigan was 578.4 feet. All values are provided by the U.S. Army Corps of Engineers Detroit District.
Groundwater Information (Jennie Atkins)
Water tables rose in November, averaging 1.17 feet higher than October. Eighteen of twenty-two monitored wells recorded increases at the end of the month.
The highest increase was at the Springfield well (Sangamon County) that ended the month 3.36 feet higher thanks to the area receiving more than 7 inches of rain in the month. During the period of November 4, 5, and 6, the well rose 2.36 feet in response to the 5.10 inches of rain recorded at the onsite weather station during the same period.
Overall, seven wells rose more than 2 feet in November.However, four wells, mainly in northern Illinois, ended the month lower. The Mt Morris well (Ogle County) was 1.18 feet lower at the end of November, the month’s largest decrease.
Wells averaged 2.78 feet above November 2023, 0.79 feet below the 15-year average, and 0.67 feet below the long-term record (Table 4).
Data sources for the IWCS include the following:
CPC - Climate Prediction Center, https://www.cpc.ncep.noaa.gov/index.php
ISWS - Illinois State Water Survey, https://www.isws.illinois.edu
MRCC - Midwestern Regional Climate Center, https://mrcc.purdue.edu/
NCEI - National Centers for Environmental Information, https://www.ncei.noaa.gov
NWS - National Weather Service, https://www.nws.noaa.gov
SPC - Storm Prediction Center, https://www.spc.noaa.gov
USACE - U.S. Army Corps of Engineers, https://www.lre.usace.army.mil
USDM - U.S. Drought Monitor, https://droughtmonitor.unl.edu
USGS - U.S. Geological Survey, https://waterdata.usgs.gov/il/nwis
WARM - Water and Atmospheric Resources Monitoring Program, https://warm.isws.illinois.edu/warm/