April 11, 2024 Climate Outlook

April 11, 2024 12:10 PM
Blog Post

Key Points

  • El Nino transitioning to La Nina during this summer; increased risk of heat
  • Still need more moisture for streamflow recovery in many areas of the state, particularly southern and eastern parts of the state
  • Good chances for the planting season to be slightly warmer than average

Past Weather

Compared to March, April temperatures have so far stayed much closer to normal. So far, no days in April have exceeded 10°F above normal. The 30-day average temperature has been from 35-50°F. These temperatures have followed the climatology quite nicely, with only a 3°F departure from mean in southeast Iowa.

During the past 30 days, as much as 6 inches of rain fell in eastern Iowa. Most of the state received around 2 to 5 inches of precipitation, with eastern and central Iowa receiving the highest amounts. These events brought at least 70% of normal precipitation to much of the state, with eastern Iowa receiving as much as 200% of normal precipitation. Precipitation departure from mean across the state for the past 30 days is as much as 3 inches. Much of the state for the last 30 days has received from 1 to 3 inches more precipitation than average. Still, precipitation totals for the past year (from April 2023 to April 2024) show around a 10-inch precipitation deficit for most of Iowa. Northeastern Iowa is enduring the greatest deficit of around 15 to 17 inches, nearly half of Iowa’s annual rainfall, which is around 35 inches of rain. The April 2023 to April 2024 precipitation departure shows a similar pattern to the current drought monitor map.

Map of Iowa showing the precipitation deficit from April 2023 to April 2024.

Drought monitor for Iowa showing greatest area of drought in northeast Iowa.

Soil moisture has improved across Iowa throughout the past month, but dryness still exists, particularly in northeast and southwest Iowa. Above average precipitation helps relieve some soil dryness, but more precipitation is needed to overcome long-term drought issues. Streamflow rates during March were still much below normal for the eastern half of Iowa. The 14-day average streamflow rates valid April 9th showed normal to below normal rates across most of the state. According to NASS crop progress reports, both topsoil and subsoil moisture are lacking in Iowa. Topsoil moisture ranks 49% short to very short in moisture and subsoil moisture ranks 64% short to very short. These are both improvements in moisture compared to last week.

Future Conditions

The 7-day Quantitative Precipitation Forecast (QPF) from the WeatherMap of United States showing forecasted quantitative precipitation valid until April 13th. Prediction Center shows most of Iowa receiving around 1 inch of rain in the next 7 days. There is a west to east gradient of rainfall amounts, with western Iowa expected to receive the least amount of rain (around 0.5 inches) and eastern Iowa to receive the most (around 1.25 inches). Keep an eye out for a chance for thunderstorms early next week.

The 6-10 day outlooks show chances for above-average temperatures and a chance for precipitation. However, we still have a chance for temperatures to cool again later in the month. The frequency of a low temperature of less than 32°F occurring between April 10th to May 31st is around 70-100% across the state. Cold temperatures are still likely as we continue toward summer, and the average last spring freeze date for much of Iowa is around April 20th. If you want to know more about the last spring freeze date in your county, check out this plotting tool.

Agricultural Considerations

Soil temperatures are near 50°F across most of the state and are expected to continue to warm with the warm air temperatures for the next week. Dry soils will warm and cool more quickly with rapidly changing air temperature. With chances for freezing temperatures still existing, monitor soil and air temperatures for the rest of the month. Soil moisture may inhibit planting next week after areas of Iowa receive precipitation.