November 2014 Central Iowa Climate Summary
Temperatures
Figure 1: The November 2014 average temperature departure from mean shows the entire state was well below normal during the month. Image is courtesy of MRCC. DMX CWA outlined in white.
November 2014 was a very cold month as the average temperature for the state was 29.1°F or 7.5°F below normal (See Figure 1). November 2014 became the 4th coldest November on record for the state. The average temperature for the Des Moines County Warning Area was fairly similar at 29.2°F. The Des Moines International Airport ended up having a monthly average temperature of 33.6°F which was 5.6°F below normal and became the 15th overall coldest November on record since 1878. Waterloo on the other hand, had an average temperature of 28.4°F for November resulting in the 6th coldest November on record at that station. Records began in Waterloo in 1895. Mason City had its 3rd coldest November ever since records began in 1890 as the average temperature was 25.6°F or 8.0°F below normal. Mason City only had 9 days when the average temperature was above normal and only 2 days when the departure from normal was 10°F or more above normal. Waterloo and Des Moines had similar temperature trends in November (See Figures 2 and 3). For instance, Waterloo recorded 20 days with below normal temperatures, 14 averaged double digits below normal. Des Moines had 13 days in which the average daily temperature was at least 10°F below normal and 9 days with 15°F or more below normal.
Figure 2: November 2014 temperature trend for Des Moines. Image is courtesy of ACIS.
Figure 3: November 2014 temperature trend for Waterloo. Image is courtesy of ACIS.
The coldest stretch in November was from the 11th to the 21st when average temperatures ranged 15 to 25 below normal for much of central Iowa (See Figure 4). During this stretch, Des Moines and Mason City set new records for consecutive days with a maximum temperature below freezing (32°F) during the month of the November (See Figures 5-7). Mason City also recorded back-to-back record low temperatures on the 20th and 21st and several other central Iowa locations set new temperature records as well in November (See Table 1). A few locations over northern Iowa dipped below zero on the 16th, 20th and 21st but the coldest day of the month didn’t occur until the 27th or Thanksgiving (See Figure 8). A brief warmup occurred on the 22nd and 23rd before the cold snap occurred on Thanksgiving.
Figure 4: Average temperature departure from mean from November 11 to November 21, 2014. Image is courtesy MRCC.
Figure 5: Des Moines set a new record of consecutive days in November when the Maximum temperature remained less than 32°F.
Figure 6: Mason City set a new record of consecutive days in November when the Maximum temperature remained less than 32°F.
Figure 7: The normal maximum temperature for November 11 to November 21. The period of average is from 1981 to 2010. Image is courtesy MRCC.
Figure 8: Average [actual] minimum temperature across central Iowa on Thanksgiving November 27, 2014. Image is courtesy MRCC.
Table 1: New Temperature Records set during November at Mason City, Waterloo, Ottumwa, and Lamoni.
Precipitation
With the bitter cold temperatures during the month of November, the bulk of the precipitation fell as snow. The monthly average precipitation for the Des Moines CWA was 0.49 inches while the statewide average was a little higher at 0.80 inches but was still 1.25 inches below normal. There were a couple light rain events during the first week of November, but any precipitation amounts remained under 0.10 inches. Otherwise, central Iowa remained dry or well below normal for liquid precipitation. On the flipside, snowfall was above normal for the month at many locations as there were several light snow events during the last two-thirds of the month. Des Moines reported at least a trace of snow on 14 days and had measurable snow on 4 of those days in November. Some light freezing rain and freezing drizzle occurred briefly on the 21st over portions east of Interstate 35. The highest and most widespread snow amounts fell on the 15th and 26th (See Figures 9 and 10). In fact, Des Moines set a new daily snowfall record on the 15th with 2.0” breaking the previous record of 1.5” set in 2005. A few locations over northern Iowa received over 6 inches on the 26th and the snow caused some travel issues before the Thanksgiving holiday (See Figures 11 and 12). However, with the brief warm up after Thanksgiving, much of the snow pack melted.
Figure 9: Snowfall amounts for November 15 into the early morning on the 16th. Image is courtesy of Iowa Environmental Mesonet.
Figure 10: Snowfall amounts from the morning of November 26, 2014.
Figure 11: Iowa DOT road conditions Snowfall as of 7 am CST on the morning of November 26, 2014. Image is courtesy of Iowa Environmental Mesonet.
Figure 12: Winterset KCCI Webcam at 7 am CST on November 26, 2014.