IEM Daily Bulletin for Aug 26 2026
daryl herzmann
Iowa Environmental Mesonet Daily Bulletin for 26 August 2026
News
No news is good newsIEM Code Pushes <repo,branch> on Github
| Timestamp | Repository | Message | Link |
|---|---|---|---|
| Aug 25 8:00 AM | iem,main | 📝 Increase ncopen timeout to workaround conflicts | Link |
| Aug 25 8:29 AM | iem,main | 📝 Misc fixes whilst migrating back to requests | Link |
| Aug 25 10:22 AM | iem,main | 🐛 Insert time zone for newly found station | Link |
| Aug 25 12:26 PM | iem,main | ✨ Denote monthly average on VTEC monthly counts https://mesonet.agron.iastate.edu/plotting/auto/?q=171 |
Link |
| Aug 25 1:55 PM | iem,main | 💚 Address test failure from previous PR | Link |
| Aug 25 2:12 PM | iem,main | 🎨 Address matplotlib cmap extremes deprecation | Link |
| Aug 25 2:40 PM | iem,main | 💚 Address codereview | Link |
| Aug 25 2:48 PM | iem,main | 💚 Address codereview | Link |
| Aug 25 8:40 AM | pyiem,main | 🎨 Remove hardcoded /tmp usage in tests | Link |
| Aug 25 3:09 PM | pyiem,main | 🎨 Address matplotlib deprecation | Link |
| Aug 25 3:18 PM | pyiem,main | 💚 Address codereview | Link |
Daily Feature
August Weather + Yield
Date: 25 Aug 05:30 AM
Votes: Good: 11
Bad: 0 Abstain: 4
Yesterday's daily feature speculated about the upcoming crop yield impact of low solar radiation days during much of this August. Today's featured chart takes a more direct look into this by comparing various weather summary values over the 1-24 August period for Ames to de-trended corn yield departures for Boone County (the county the weather station resides). The top left panel shows the yearly NASS county corn yield estimates with a number of fits plotted. The red line denotes the simple linear trend and is used to compute a yearly departure value used within all other sub-plots. Eight different yearly weather summary values are plotted against this de-trended yield value. Of note for today is the upper left most plot showing daily average solar radiation as estimated by ERA5-Land. Since long term observations of solar radiation generally do not exist, a model is used to estimate the daily values. At least for this plotted metric, the relationship is not all that exciting as a simple explainer for yield outcomes. As is the general comment for plots in this space, if the relationship was simple/easy, folks would be making a fortune in the futures market!
The featured media can be generated on-demand here
.NWS Watch/Warning Summary for 12 AM 25 Aug 2026 - 12 AM 26 Aug 2026 CDT
| Summary | By WFO | Watches | ||||||
|---|---|---|---|---|---|---|---|---|
| Type | US | IA | ARX | DVN | DMX | OAX | FSD | US |
| Tornado | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Svr Tstorm | 100 | 0 | 0 | 0 | 0 | 0 | 2 | 2 |
| Flash Flood | 10 | 0 | 0 | 0 | 0 | 0 | 0 | --- |
ARX = LaCrosse, WI DVN = Davenport, IA DMX = Des Moines, IA OAX = Omaha, NE FSD = Sioux Falls, SD
IEM Cow Report
SVR+TOR Warnings Issued: 101 Verified: 29 [28.7%] Polygon Size Versus County Size [21.7%] Average Perimeter Ratio [17.8%] Percentage of Warned Area Verified (15km) [16.8%] Average Storm Based Warning Size [2046 sq km] Probability of Detection(higher is better) [0.81] False Alarm Ratio (lower is better) [0.71] Critical Success Index (higher is better) [0.27]
IEMBot Social Media Posts
IEMBot can be configured to post messages to a number of social media services. More details: IEMBot Homepage.
Posts yesterday per supported service:
- ATMosphere (bluesky only attm): 1,952
- Mastodon / Fediverse: 18
- Slack: 1,611
- Twitter/X: 8,652
- HTTP Webhooks: 133
- Weather.IM Jabber Chatrooms: 11,524