The statewide average temperature was 49.9°F or 1.0°F above normal (See Figure 1). April 2016 became the 57th warmest April out of 144 years of statewide climate records. The monthly average temperature at Des Moines was 54.2°F or 2.5°F above normal which was the 22nd warmest March for that station since records began in 1878. At Des Moines, the highest temperature was 83°F on the 3rd and the lowest was 25°F on the 9th. Waterloo’s monthly average temperature was 49.1°F or 0.2°F above normal. The highest temperature at Waterloo was 80°F on the 16th while the coldest was 16°F on the 9th.
At the beginning and end of the month, temperatures were generally below normal. During the middle weeks of April is when the above normal temperatures prevailed. The warmest period occurred from the 13th to the 26th (See Figure 2). A pair of hard freezes occurred on the 9th and 12th of the month where the 9th was the coldest day across the state (See Figure 3). The coldest temperature of the month was 13°F in Audubon on the 9th. Sheldon, Spencer, and Webster City all recorded 16°F low temperatures on the morning of the 12th. The month’s highest temperature was 85°F at Little Sioux on the 3rd and then Donnellson reached the same temperature on the 25th. Dreary and damp weather set in across the state during the final four days of the month and kept temperatures well below normal, especially maximum temperatures (See Figure 4).
The statewide precipitation total was 3.07 inches or 0.44 inches below normal. For the entire month, precipitation totals were above normal across western Iowa while the north central to northeast had the lowest amount of precipitation (See Figure 5). April 2016 became the 68th wettest April among 144 years of climate records. The total precipitation at Des Moines was 3.37 inches or 0.49 inches below normal while Waterloo totaled 2.60 inches or 1.11 inches below normal for the month.
Abnormally dry weather conditions reigned during the first 18 days of April when no measurable precipitation occurred over west central to southwest Iowa (See Figure 6). During the last 12 days of the month, a more active and wet pattern developed across the state (See Figure 7). In fact, the statewide average precipitation during the first 18 days was 0.57 inches, while the final 12 days averaged 2.50 inches. The hardest hit area was western Iowa the last 2/5 of the month and caused several rivers and streams to become bank full or even reached minor flood stage by early May. April 2016 totals ranged from 0.75 inches at Marquette to 7.52 inches at Alta. Another comparison, Guttenberg had its driest April since 1942 while Sioux City recorded its wettest April since 1998. A cold, dreary, and soggy end to the month plagued the entire state, but the precipitation totals were recorded on the morning of the 1st of May and will be recorded in the May 2016 precipitation total.
There was very little severe weather throughout the month as the first 18 days were fairly inactive. Only 2 days had severe weather which were the 24th and 27th of April. Northwest Iowa had high winds and large hail on the 24th while on the 27th had 5 tornadoes that occurred in southwest Iowa, including an EF1 in Stanton, Iowa. For a summary of the event, visit: http://www.weather.gov/dmx/160427summary. As far as non-thunderstorm activity, there were several high wind events that occurred during the first 8 of 9 days of the month. This is not uncommon as early April is typically the windiest time of year in Iowa.
Blog post by Kenny Podrazik – NWS Des Moines