The dry spell over the last month or so continues to have an impact on the region. 64% of the state is currently under an abnormally dry drought (up six percent), with 35% in moderate (up 13%) and 2% in severe. This brings the total estimated population under drought impacted areas to 1,004,019.
The chart above shows the areal coverage statewide of the different levels of drought. As you can see, abnormally dry to moderate drought is almost a usual occurrence at some point in the year locally, but it has been quite a long time since we last saw severe or extreme drought – June 24, 2014 for the former and November 5, 2013 for the latter. This is the sharpest increase since around that time, and the current forecast does not look to have major relief anytime soon.
Burn bans are in effect until further notice for four counties in the state – Plymouth, Buena Vista, Crawford, and Wapello counties. Burn bans are requested by county emergency management or fire personnel that believe open burning is too dangerous to be conducted within the county.
The maps above illustrate the precipitation departures for July 2017 (observed/recorded precipitation – climatological averages), truly showing a two-sided story. Northeast Iowa is much higher on the scale thanks to their flooding rains that they received earlier this week, from a +1.81″ in Clinton to a whopping +11.17″ near Prairie Du Chien, WI. The other side of the story shows -2″ to -4″ departures for central to western thirds of the state. The centered map overlays the drought monitor on top, showing that moderate drought encompasses those aforementioned areas. The final chart was featured in the IEM Daily Bulletin this morning, with the following thoughts offered alongside:
The large disparity with July precipitation in Iowa does not look to change with the few days left in the month. The featured chart displays the distribution of July precipitation totals for the long term climate sites tracked by the IEM. The distribution this year is shown to be shifted a bit to the left of the long term climatology, assuming a normal distribution. The actual histogram for this year shows many more sites with below average precip than would be indicated by normal. (Iowa State University/Iowa Environmental Mesonet)
As mentioned above, some agricultural impacts are beginning to be felt across the state as a result of drought. 29% of pasture and range is being listed as “poor” or “very poor,” however it is notable that well over 60% of corn, soybeans, and oats are being listed as “good” or “excellent.” Soil is taking the bigger hit statistically with 52% of topsoil being listed as “short” or “very short,” with that number being 46% for subsoil. Corn silking remains above average, though dough is 6% behind from average. Soybeans are above average across the progress board, with oats 8% behind from average. (USDA Crop Progress Report)
Long Term Outlook
A look at the 6-10 day precipitation probability outlook from the Weather Prediction Center shows below average precipitation chances. Bottom line: severe drought is occurring and expected to continue and expand in the next few weeks. Agricultural impacts will increase as we get further into August. If there is any good news to this, is that equal precipitation chances return for the outlooks beyond 10 days. Check out our Climate page for further information on that.
The Iowa Weather Network will continue releasing weekly drought updates for the extent that severe drought or greater exists within the state.