November 2023 Overview
November temperatures were above, and precipitation was below the long-term average in Illinois. Mean streamflow statewide was below the median for the month. Shallow groundwater levels were below the long-term depths.
Air temperatures averaged 43.1 degrees in November, 0.9 degrees above the 30-year normal (Figure 1). November temperatures ranged from the high 40s in northern Illinois to the high 50s in southern Illinois.
Precipitation statewide in November was 0.68 inches, 2.4 inches below the 30-year normal, and the eighth driest November on record statewide (Figure 1). The monthly total precipitation ranged from nearly 3 inches in northeast Illinois to less than half an inch in parts of south-central Illinois.
Soil moisture, on average, decreased 14 percent at 2 inches in November, ending the month with an average of 0.26 water fraction by volume (wfv). Decreases were seen throughout the soil column down to 59 inches.
Mean provisional streamflow aggregated statewide was below the long-term median flow for November, about 70 percent of median (Figure 1). Monthly mean discharge values in November ranged from much below normal to normal for the month.
Water surface levels at the end of November were below the full pool or target level at 20 of 22 reporting reservoirs. At the end of November, Lake Shelbyville was 1.0 foot below the seasonal target level, Carlyle Lake was 0.4 feet below the seasonal target level, and Rend Lake was 1.3 feet below the spillway level. Lake Michigan’s mean level was above its long-term mean for the month.
Shallow groundwater levels were 3.35 feet below the long-term average at the end of November (Figure 1). Levels averaged 0.47 feet below those in October and 1.58 feet below last year’s levels.
Weather/Climate Information
The following description of temperatures, precipitation, drought, and fall weather conditions 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 warmer and much drier than normal statewide. Climatological fall was also warmer and much drier than normal.
Temperatures averaged 43.1 degrees in November, 0.9 degrees above the 30-year normal and the 36th warmest on record statewide. November temperatures ranged from the high 40s in northern Illinois to the high 50s in southern Illinois, around 1 degree above normal (Figure 2, Table 1a). Several places saw high temperatures into the 80s in early to mid-November, including 84 degrees in Lawrenceville and 82 degrees in Cahokia. Meanwhile, the last week of the month brought some extremely low temperatures, including 3 degrees in Minonk and 4 degrees in Aurora. The coldest point in the state last month was Elizabeth at 36.6 degrees, and the warmest point was Lawrenceville at 49.1 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 0.68 inches, 2.4 inches below the 30-year normal, the eighth driest November on record statewide, and the driest since 1999 (Figure 3, Table 1a). Most of Illinois got a good shot of rain in late October and the first snowfall around Halloween. The state then moved into a much drier weather pattern that persisted for most of November. The monthly total precipitation ranged from nearly 3 inches in northeast Illinois to less than half an inch in parts of south-central Illinois. Northern Illinois was 1 to 2 inches drier than normal, and southern Illinois was 3 to 4 inches drier than normal (Figure 3).
Drought: The good harvest weather this fall did not help our persistent drought conditions. While the timely July and August rain largely saved the 2023 crop, it did very little to assuage low stream, pond, and water table levels. These hydrological conditions were more affected by the state’s nearly 10-inch water deficit accumulated between April and November this year. Among the hydrological drought impacts was another harvest season with problematic low levels along the Mississippi River and reduction in barge traffic. The Mississippi River hit a record low discharge for the second consecutive year, and locally, the extended dryness penetrated below the rootzone and has affected water table levels across the state. The legacy effects of the 2023 and 2022 droughts take much longer to recover than topsoil moisture and are important conditions to monitor through the winter into spring 2024. Neither our existing dry soils nor the potential for a dry winter necessarily guarantee we will be dealing with drought conditions next spring or summer. But those drier conditions can hasten drought onset and impacts with poorly timed dry spells in the next growing season.
Fall: November wrapped up a warmer and drier than normal fall season (Table 1b). The statewide fall average temperature in Illinois was 56.1 degrees, 1.5 degrees above the 30-year normal and the 17th warmest on record. Fall 2023 total precipitation was 6.29 inches statewide, 3.4 inches below normal and the 21st driest fall on record. This past season was also the fourth consecutive drier than normal fall in Illinois, and the second consecutive top 25th driest on record statewide. With only 4.37 inches of average total precipitation, last season was the third driest fall on record in the Southwest Illinois Climate Division, and the second driest on record in both Fayette and Randolph Counties.
Illinois Climate Network (ICN) (Jennie Atkins)
The Illinois Climate Network (ICN) consists of 19 stations across the state that collect hourly weather and soil information.
Winds averaged 6.2 mph in November, 0.2 mph higher than in October but 1.6 mph lower than the network’s long-term average. ICN Bondville (Champaign County) again had the windiest month with an average of 9.7 mph. The highest measured wind gust was 35.6 mph, recorded on November 8 at ICN Carbondale (Jackson County).
Temperatures were 13 degrees F lower than in October, averaging 43 degrees for the month or 1 degree higher than the long-term average. Monthly highs ranged from the high 60s to low 80s with lows from 0 to the low 20s. The highest temperature was 82 degrees, recorded at ICN Carbondale (Jackson County) on November 7. The lowest temperature was 0 degrees, measured at ICN Monmouth (Warren County) on November 28.
Soil temperatures were 13 to 14 degrees lower in November with averages in the mid- to high 40s. Under bare soils, temperatures at 2 inches ranged from 27 to 75 degrees and from 32 to 71 degrees at 4 inches. Temperatures under sod ranged from 36 to 66 degrees at 4 inches and 33 to 65 degrees at 8-inch depths.
Precipitation was low across the network. Network totals ranged from 0.60 inches at ICN Olney (Richland County) to 1.40 inches at ICN Belleville (St. Clair County). All stations recorded less than half of their November normals. Overall, the network had an average of 0.87 inches of precipitation for November, 2.04 inches below the long-term average.
Soil moisture declined in southern and central Illinois with little overall change at the northern stations. Levels at 2 inches fell an average of 14 percent across the network in November. The highest decreases occurred at the southern stations, while levels in the north showed no overall change. Similar patterns were seen through the top 8 inches.
Slight declines were seen in the deeper depths. Moisture levels at depths from 20 to 59 inches were 2 to 5 percent lower at the end of November. This continues the drying trends seen at the deeper depths in 2023. Soil moisture decreased 32 percent at 20 inches, 20 percent at 39 inches, and 12 percent at 59 inches between April and the end of November.
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 the past record of monthly mean flows at those stations for the same month. Both recent and long-term data are retrieved from U.S. Geological Survey (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 the 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 below the median value for November (approximately 70 percent of the median) and below the mean for November (approximately 40 percent of the mean). Monthly mean discharge values in November ranged from much below normal to 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 the 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 an 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 21 reservoirs for which levels were reported last month and this month, reported end-of-November water levels were lower at 13 reservoirs, higher at 5 reservoirs, and about the same as at the end of October at 3 reservoirs. For the 22 reservoirs with measurements reported for the end of November, water levels were below normal target pool or spillway level at 20 reservoirs and above normal target pool or spillway level at 2 reservoirs. Kinkaid Lake’s level was drawn down intentionally for annual maintenance. Inflow to Salem Lake was supplemented by pumping from Carlyle Lake at the end of the month. Inflow to Lake Paradise was supplemented with pumpage from Lake Mattoon. Nominal target levels of Lake Decatur and Lake Springfield in this month’s Table 3 reflect upcoming winter values.
Major Reservoirs. Compared to water levels at the end of October, at the end of November the water level at Lake Shelbyville was 0.2 feet lower, Carlyle Lake was 0.2 feet lower, and Rend Lake was 0.7 feet lower. At the end of November, Lake Shelbyville was 1.0 foot below and Carlyle Lake was 0.4 feet below the seasonal target level, and Rend Lake was 1.3 feet below 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 2023 mean level for Lake Michigan was 579.1 feet. The monthly mean level one year ago (November 2022) was 579.3 feet. The long-term average lake level for November is 578.8 feet, based on 1918–2022 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 579.0 feet. All values are provided by the U.S. Army Corps of Engineers Detroit District.
Groundwater Information (Jennie Atkins)
Water tables continued to decline in November with more than 80 percent of the monitored wells lower than at the end of October.
Levels dropped 0.47 feet on average for the month (Table 4). Most declines were small, less than 1 foot. However, November is the eighth month in a row to show declines from the previous month. Tables have only increased twice within the past 12 months, in February and March 2023.
The largest impacts were again seen in western Illinois. The Belleville well (St. Clair County) fell 1.06 feet in November, ending the month 7.95 feet lower than in 2022 and 9.55 feet below the 15-year average. The Perry well (Pike County) was 8.64 feet lower than in 2022 and 8.36 feet lower than its 15-year average. There was no measured decline at Perry for November since the water table is lower than the ability to measure it.
Wells averaged 1.58 feet below the November 2022 level, 3.90 feet below the 15-year average, and 3.35 feet below the long-term record.
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://www.isws.illinois.edu/warm
