Key Points
- Heat expected to return after some cooler-than-average temperatures this past week.
- Keep an eye out for flash drought as excessive heat is expected.
- A warm signal persists through the next three months as ENSO neutral is expected to transition to La Niña by this fall.
Past Weather
For many Iowans, the last 7 days were mostly dry. Much of the state received less than 1” of rain, however, some folks in Kossuth County received 2 or more inches. Isolated showers continue to cause spatial variability in rainfall amounts across the state.
Daily temperatures across the state in the past week averaged 66 to 72 degrees Fahrenheit, which is around 2 to 6 degrees cooler than normal. Daily temperature is the average between daily high and low temperatures. Both daily high and low temperatures were generally lower than normal in the past week.
Crop Update
This week’s NASS crop progress shows corn conditions are 75% good to excellent, which is up 1% from last week. Soybean conditions are 74% good to excellent, which is up 2% from last week. There is variability across the state in terms of reproductive stages of crops due to variable planting dates and replating because of the rainy spring. Some soybean acres have yellow patches where there was excessive soil moisture or ponding. 68% of corn acres are silking and 69% of soybean acres are blooming. The derecho on Monday, July 15, resulted in damaging winds up to 100 mph and some brief, weak to moderate tornadoes in eastern Iowa. Some crop damage occurred as a result.
Climate Outlook
The Weather Prediction Center quantitative precipitation forecast shows anywhere from 0.00-1.00 inches of rain falling across Iowa in the next 7 days. Much of the state is expected to receive very little rain. Eastern Iowa is forecasted to receive the greatest amounts, totaling 1” or less.
The Weather Prediction Center Day 3-7 hazards outlook valid July 28-August 1 shows heavy rainfall in Minnesota and parts of northern Iowa on July 28-29 and hazardous heat expected in Iowa July 29 through August 1. The Climate Prediction Center 8–14-day hazards outlook shows slight to moderate excessive heat persisting in Iowa from August 1-7. Be prepared for excessive heat; remember to stay hydrated and take breaks when needed.
The 6-10 outlook (valid July 31 – August 4) from the Climate Prediction Center shows a warm signal across Iowa, with a 70-80% chance of temperatures being greater than normal. Chances for precipitation are leaning slightly below normal. The 8–14-day outlook (valid August 2-8) shows temperatures remaining above average, with a 60-70% chance. Chances for precipitation continue to lean slightly below normal. Higher percentages mean there is higher confidence in above average temperatures.
The 3–4-week outlook continues to show a 50-55% chance of above normal temperatures and precipitation shows equal chances for above, below or normal. The one-month outlook for August, issued July 18, shows temperatures are expected to lean slightly above normal and precipitation has an equal chance for above, below, or normal. The seasonal outlook shows a warm signal and leaning below average for precipitation.
ENSO neutral conditions are expected to continue over the next several weeks, with a La Niña watch in place. La Niña has a 70% chance of developing during August to October. Once La Niña has developed, it is expected to persist into winter, which could increase chances for a colder winter in Iowa.
