5th Warmest November, 2nd Warmest Fall in Illinois

Temperature

This was the 5th warmest November on record for Illinois, based on preliminary data. The statewide average temperature was 47.4 degrees, and 4.9 degrees above normal. Here are the top ten warmest Novembers in Illinois since 1895:

  1. 2001 with 49.9°F
  2. 1931 with 49.1°F
  3. 1909 with 48.8°F
  4. 1999 with 48.4°F
  5. 2016 with 47.4°F 
  6. 2009 with 47.2°F
  7. 1902 with 46.9°F
  8. 1990 with 46.8°F
  9. 2015 with 46.6°F
  10. 1913 with 46.4°F

It was also the 2nd warmest fall on record for Illinois. The statewide average temperature for fall was 59.4 degrees, 5 degrees above normal. Only the fall of 1931 was warmer at 59.8 degrees. The climatological fall months are September, October, and November.

Precipitation

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Warm, Wet November in Illinois

Summary: Illinois just finished its third wettest and tenth warmest November on record. Even with the warmer conditions, significant snowfall fell across the northern half of the state over the weekend before Thanksgiving.

Precipitation

The statewide precipitation total was 5.60 inches, 2.13 inches above average and the third wettest November on record. In first place was 1985 with 9.05 inches, and in second place was 1992 with 6.51 inches. I remember November 1985 quite well – it was overcast every day and dreary the entire month.

The largest reported precipitation total for November was Rock Island Lock and Dam with 8.39 inches. This was followed closely by Sparta (IL-RH-8) with 8.09 inches. Precipitation includes both rainfall and the water content of snowfall.

Here is the map of total precipitation for November. Areas in yellow and orange received 6 to 9 inches of precipitation. Areas in the shades of green were not quite as wet but received between 3 and 6 inches of precipitation.

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Rainfall Totals from the Recent Storm

A large, slow-moving low-pressure system passed through the central US this week, bringing widespread rains from Louisiana all the way up the Mississippi River Valley. Areas in yellow and beige received 2 to 4 inches of rain, including large parts of Illinois. Some counties along the Illinois-Indiana border received amounts in the 1 to 2 inch range. Meanwhile, areas in Missouri and Arkansas received 5 to 8 inches.

The largest amount reported in Illinois in the last three days was 3.95 inches in White Hall, IL. White Hall is in Greene County and where my great-grandparents lived.

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Here are the rainfall departures for November so far. Areas in green are between half an inch and two inches above average. Areas in blue are two to four inches above average. This should pretty much erase any concerns about dry conditions earlier this fall.

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By the way, these maps came from a NWS product at http://water.weather.gov/precip/

Cold Week for the US

It has been a very cold week in the US with temperature departures in the central US at 15 to 25 degrees below average. Yesterday, Champaign-Urbana was 26 degrees below average for the date and just 2 degrees shy of the record low of 6 degrees set back in 1891.

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Here is the temperature departure for today from the site Climate Reanalyzer showing the bitterly cold temperatures in the eastern half of the US, while once again Alaska is well above average. We saw this pattern most of last winter, starting in late November.

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Here is the plot of the jet stream (high winds at upper levels of the atmosphere – shaded in yellow and red) showing its dip down into the southern US. That means we pretty much have an open door to cold Arctic air in the Midwest.

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Cold Start to November in the Midwest

So far, November has been cooler than average across Illinois and the eastern two-thirds of the Midwest (below). The statewide average temperature is about 5 degrees below average.

The NWS forecasts indicate that temperatures are likely to stay below-average for the next two weeks across Illinois and the Midwest. The second and third maps are the latest NWS 6-10 and 8-14 day forecasts.

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November 2013 in Illinois – Cold and Dry

November 2013 will always be remembered for the tornado outbreak on November 17, 2013, that produced 25 tornadoes across Illinois based on the latest reports. Much has been written on that subject in this blog and elsewhere. While not as dramatic, November 2013 in Illinois was colder and drier than average.

Precipitation

The statewide precipitation was 2.6 inches, 0.9 inches below the 1981-2010 average. This is the fifth month with below-average precipitation for Illinois. Since July, the statewide precipitation has been 12.2 inches and 5.4 inches below average. That ranks as the 15th driest July-November on record. It is in stark contrast to the first half of 2013 which was the wettest January-June on record with 29.0 inches.

Snowfall was common in the northern half of the state in November. Snowfall amounts were heaviest in the northwest corner of the state and in the range of 4.0 to 4.6 inches in the Galena area.

Temperature

The statewide temperature for November was 38.3 degrees, 4.2 degrees below average. While cold, it was far from the coldest November on record. That record stands at 33.6 degrees in 1976. Many places in Illinois experienced both spring-time temperatures and winter chill in November.

The warmest day of the month was November 17 as warm, moist air moved in from the south ahead of a strong cold front. This warm, moist air helped fuel the tornado outbreak. Just a week later low temperatures dropped down into the teens. For example, Chicago O’Hare Airport reported a high of 69 degrees on November 17 and a low of 11 degrees on November 24. That is a 58-degree change in temperature in 7 days.

Maps

Below are the summary maps for November precipitation accumulation, November precipitation departures, and snowfall accumulation. The outstanding features are the widespread dryness around the state as shown in the second map and the widespread report of snowfall in the northern half of the state.

Note: the word average used in the text and the word normal used in one of the maps below refers to the 1981-2010 average. 

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Washington IL EF-4 Strongest on Record in November for Illinois

Based on the evidence so far, the Washington IL EF-4 tornado is the strongest November tornado on record for Illinois since modern records began in 1950. 

The EF-3 tornado in Gifford is possibly only the third tornado of that magnitude since 1950.

One of the other EF-3 tornadoes occurred on November 15, 1988, in Madison and St. Clair Counties. The other EF-3 tornado occurred on November 19, 1991 in Marion (Williamson County). There is some confusion about this event. While it is listed as an EF-3 in the NOAA Storm Prediction Center database, the Marion History Preservation site stated that at one point the NWS declared it to be a microburst. Another source said it was later decided to be an EF-3 tornado. I am going to consider the Storm Prediction Center database as the final word on that one. 

Using a database from the NOAA Storm Prediction Center, I found 62 tornado reports from 1950 to 2012 for November in Illinois. Here is the breakdown by Enhanced Fujita-scale and the earlier Fujita-scale:

  1. EF-0: 19 cases
  2. EF-1: 23 cases
  3. EF-2: 18 cases
  4. EF-3: 2 cases
  5. EF-4: 0 cases
  6. EF-5: 0 cases

Note #1: older tornadoes were rated using the original Fujita damage scale. In 2007, the NWS has shifted to an Enhanced Fujita damage scale. Even though the damage assessments have changed to include more information, the intent is to still allow comparisons between older and newer tornado events.  For the sake of this post, I am using the term “EF” to refer to tornado strength in both the original and enhanced Fujita scale. 

Note #2: the 62 tornadoes in November for Illinois in this Storm Prediction Center database is lower than the 68 tornadoes in November for Illinois found in an earlier study from 1950-2010 using data from the National Climatic Data Center.