IEM Daily Feature
Thursday, 06 December 2012

Day Two Dives

Posted: 06 Dec 2012 05:35 AM

After setting a record high temperature on Monday of 69 degrees, the high on Wednesday for Des Moines was only 46 degrees (still above average though) making for a 23 degree change over the two days. Is this typical? The featured chart presents the monthly distribution of two day high temperature change after a day of setting or tieing the record high. While actual data goes back to the late 1800s, the period up until 1930 was used as a "warm up" for this chart. The box plots used on the chart show the median (red line), 25th and 75th percentiles (box bounds) and the whiskers represent the 2nd and 98th percentiles. For December, the current change of 23 degrees is only slightly lower than the long term median, so it is about what we would expect. Postive values on this chart would indicate the day two temperature was warmer than the record setting temperature. This situation appears to be the most common in July as record warmth tends to provide conditions for more record warmth. In the winter season, record warmth is from a displaced air mass that is often replaced by a colder air mass with the passage of a storm system.

Good = 29
Bad = 9

Tags:   records   highs