IOWA PRELIMINARY WEATHER SUMMARYWritten by Theresa Rose on July 19, 2016
By Harry Hillaker, State Climatologist, Iowa Department of Agriculture & Land Stewardship
The past reporting week began with very warm and humid conditions and widespread rain fall. Monday (11th) was the warmest day of the reporting week with daytime high temperatures in the upper eighties to mid-nineties. Thunderstorms were widespread from Monday (11th) evening through Tuesday (12th) morning with heaviest rainfall in the southwest where one to two inch amounts common. Thunderstorms were again widespread on Wednesday as a cold front moved across the state. The greatest rainfall on Wednesday was from Des Moines eastward along the I-80 corridor with amounts around an inch. Mostly dry weather, with much lower temperatures and humidity, prevailed from Thursday through Saturday (16th). Finally, much higher humidity moved back into Iowa Saturday night and Sunday (17th) with the moisture surge bringing rain statewide early Sunday (17th) morning with two to three inch rain totals common from the Iowa Great Lakes region eastward to the Mason City and Decorah areas. Rain totals for the week varied from only 0.10 inches at Rock Rapids to 4.38 inches near Storm Lake and 4.28 inches at Lake Mills. The statewide average precipitation was 1.65 inches or well above the weekly normal of 1.05 inches. Temperature extremes ranged from a Monday (11th) afternoon high of 94 degrees at Des Moines to a Saturday (16th) morning low of 49 degrees at Elkader. Temperatures for the week as a whole averaged 1.1 degrees below normal. Finally, each of the rain events this week brought severe weather to the state as well. Monday (11th) evening and night saw numerous reports of high winds, especially over west central Iowa. Wednesday (13th) saw several reports of large hail in northwestern and west central Iowa and numerous high wind reports along and near I-80 in central and east central Iowa. Finally, the most damaging weather of the week came with a derecho which entered the northwest corner of Iowa about 1 a.m. Sunday (17th) and finally exited the state in the Quad Cities area about five and one-half hours later.