The warm temperatures on Monday gave way to late afternoon and early evening thunderstorms that brought hail to the Des Moines Metro and other places over Iowa. The featured map presents a summary of Local Storm Reports (LSR)s issued by NWS Des Moines for hail Monday evening. The largest hail report listed was 1.25" over Waukee (west Des Moines suburb). The autoplot tool that generates these maps is a downstream infographic associated with the raw NWS LSR Text (scroll to the bottom). The IEM has a number of ways to view and download LSR data, including the LSR App and data download. For a pro-tip, if you know the three character NWS office identifier, you can enter the combination of LSR and that identifier into the upper right search box and be taken to the most recently issued LSR from that office along with the map graphic like is featured today.
The featured map combines Weather Prediction Center seven day precipitation forecast with last week's Drought Monitor. The prediction paints a much needed wet start to April over Iowa. It is getting down to crunch time for precipitation deficits to be made up prior to the start of the growing season. It is also a good time to make up such deficits as it is still too early for farmers to plant crops and soils are no longer frozen. The only downside to this forecast is far western Iowa with totals that are not much higher than climatology this time of year, but something is better than nothing!
Yesterday's Daily Feature presented a considerable amount of needed precipitation forecast to fall during the first part of April. The first two days of April have lived up to that forecast with much of the state already over an inch. The featured map presents NOAA MRMS precipitation estimates for the first two days of April. These totals will be added to today with multiple rounds of showers and thunderstorms expected.
The National Weather Service Damage Assessment Toolkit (DAT) is a post-event storm survey platform that provides information from NWS damage surveys typically following tornado events. NWS Quad Cities / Davenport has completed a couple of such surveys following tornadoes during storms last week. The IEM offers a visualization of the "DAT tracks" that combines NWS Tornado Warnings along with an estimated track timing. The shown tornado tracked just southeast of Maquoketa. There are also Public Information Statements (PNS) associated with these DAT events with this PNS covering this featured tornado. The IEM also maintains a simple google email group that anybody can subscribe to receive emails when the NWS publishes such PNS damage survey results.
A very narrow band of snow developed overnight and dumped a stripe of an inch or more from about Omaha to Lamoni. The featured map will be updated later today, but totals will be difficult to accurately report as the snow yet falling this Tuesday morning will likely be quickly melting or transitioning to rain. Daytime snowfall events are difficult this late in the cold season as temperatures are typically too warm and even meager sunshine will warm ground surfaces above freezing. The largest report so far is a CoCoRaHS report of 5.5 inches at Creston!
The IEM website attempts to produce products and curate archives useful for research at ISU and beyond. One of the seemingly Internet unique archives is of National Weather Service Terminal Aerodome Forecasts (TAF)s. The NWS issues forecasts tailored for the aviation industry for many airports. These forecasts include wind speeds, visibility, and ceilings/cloud cover. The featured infographic attempts to summarize a TAF issued by NWS Des Moines for the Des Moines Airport from Tuesday afternoon into Wednesday afternoon. It shows strong winds and wind shear on Wednesday, but not much cloud concerns with the computed flight condition of VFR shown for most of the day. You can find archives of raw TAF text and processed data for download. There is also a more programatic TAF API service available as well.
The weekly US Drought Monitor will be released later this morning and likely show some improvements thanks to the heavy rains over the past week, but Iowa is still has a ways to go before being drought free. The driest areas of the state continue to be mostly confined to the SE, SW, and NW corners of Iowa. The featured map presents an IEM computation of the percentage of weeks since the start of 2025 that analyzed drought of at least "D1: Moderate Drought" was present. There's an interesting sliver of area from Creston to south of Des Moines that has avoided D1+ over this period! The near term forecast has plenty of significant rainfall chances, so hopefully continued drought busting can occur before the start of the 2026 growing season!
Along with numerous chances for rain, the near term forecast looks rather warm with low temperatures starting off next week in the 60s! Iowa's weather during April can sometimes feel like winter and sometimes like summer! The featured chart looks into high temperature distributions over approximately the first half and second half of the period of record for Ames. A frequency distribution estimate is plotted for each period within the top panel and the difference between the two is plotted within the bottom panel. It is interesting to denote the tails of the recent period distribution having slightly higher frequency than the first half of the period of record. The right hand table lists out percentile values for both (please note the unfortunate tight visual spacing between the 99.5th and 99.9th values). Anyway, this autoplot can be used to compare various periods of your choice and you can see what changes have been observed.
Warm and rather muggy for April weather is forecast for much of this week along with continued chances of rain. Daily low temperatures will be rather warm, buoyed by the aforementioned humid conditions. A daily low temperature of 60°F may be possible this week and such events are somewhat rare for April. The featured chart presents the frequency of a given day of April having such a warm low temperature for Ames. Each bar is labelled with the number of such events on record with the bar height plotting the frequency. Overall, these events are a one in three year recurrence.
It certainly felt a bit like summer on Monday with temperatures in the upper 70s and low 80s along with very muggy for April humidity levels. The featured chart presents the hourly maximum reported dew point temperatures for Ames during April. Observations on Monday were not too far from these maximums shown and even tied a maximum of 64°F at 10 PM. The heat and humidity helped to fire late afternoon thunderstorms over northern Iowa. We'll have more of the same through out this week before cooler and less humid weather arrives for the upcoming weekend.
For mid April, humidity levels do not get much higher than they were on Monday over most of Iowa. The heat and humidity again helped to fire afternoon thunderstorms with many of them producing severe weather over eastern Iowa. Based on hourly reports, Des Moines topped out at a dew point temperature of 66°F. The featured chart presents the observed max dew point for the year to date period ending 14 April for Des Moines. The 66°F value yesterdays ties for second place behind a 69°F reading back in 1981 (note, that value is somewhat suspect after some review, but alas). Historical archives of dew point temperatures are not really official data nor is the IEM accounting of it, so more caveats to be had with such metrics.
Wednesday saw multiple rounds of severe weather impact Iowa with a number of locations receiving significant and damaging hail. After a main line of storms developed over central Iowa during the afternoon hours and pushed into Eastern Iowa, there was some optimism that the severe weather was done for the evening over central Iowa. Instead, more storms developed just before sunset and brought another round of hail to central Iowa. The featured "postage stamp" plot takes a look at one forecast model's (HRRR) simulated RADAR reflectivity forecast valid 8 PM Wednesday (1 UTC on 16 April 2026). The upper left plot is the "verification" / observed RADAR mosaic produced by the IEM. The other 15 panels are time lagged sequential forecasts from the HRRR, since the HRRR produces a new forecast every hour. The HRRR model is one of the main tools in the near-term weather forecast toolbox, but follows the adage of all models being wrong but some are useful. Some of the earlier forecast runs picked up on the development of storms over central Iowa, but others had near no storms forecast at 8 PM.
It has been a very active week for severe weather over Iowa. While Thursday was a very welcome break from the rough weather this week, strong thunderstorms are very likely Friday with eastern Iowa that primary target for the worst of the storms. The featured chart presents the daily number of combined Tornado and Severe Thunderstorm Warnings issued by the National Weather Service for counties within Iowa. It is likely that four days for this week will have a higher total of such warnings than any previous day so far this year!
