IEM Daily Bulletin for Apr 16 2026
daryl herzmann
Iowa Environmental Mesonet Daily Bulletin for 16 April 2026
News
No news is good newsIEM Code Pushes <repo,branch> on Github
| Timestamp | Repository | Message | Link |
|---|---|---|---|
| Apr 15 9:56 AM | iem,main | 🐛 Fix csector bugs with WaWA summary autoplot https://mesonet.agron.iastate.edu/plotting/auto/?q=260 |
Link |
| Apr 15 1:40 PM | iem,main | 📝 Sundry updates per review | Link |
| Apr 15 2:32 PM | iem,main | 🐛 Address NBM logic in MOS table https://mesonet.agron.iastate.edu/mos/table.phtml |
Link |
| Apr 15 9:47 PM | iem,main | 🐛 Fix grid orientation | Link |
| Apr 15 10:30 PM | iem,main | 🔥 Remove unneccessary TLS hacks for ArcGIS Online | Link |
| Apr 15 10:34 PM | iem,main | 🩹 Workaround more GIGO within MADIS HFMETAR | Link |
| Apr 15 11:04 PM | iem,main | 🎨 Prevent a confusing day0 plot from appearing | Link |
| Apr 15 9:38 AM | iem-web-services,main | 🚧 Add dbuser shim for meteobridge | Link |
Daily Feature
Early Year Max Dew Points
Date: 15 Apr 05:30 AM
Votes: Good: 10
Bad: 1 Abstain: 1
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.
The featured media can be generated on-demand here
.NWS Watch/Warning Summary for 12 AM 15 Apr 2026 - 12 AM 16 Apr 2026 CDT
| Summary | By WFO | Watches | ||||||
|---|---|---|---|---|---|---|---|---|
| Type | US | IA | ARX | DVN | DMX | OAX | FSD | US |
| Tornado | 34 | 5 | 0 | 6 | 1 | 0 | 0 | 3 |
| Svr Tstorm | 246 | 46 | 2 | 7 | 32 | 9 | 0 | 6 |
| Flash Flood | 16 | 5 | 0 | 5 | 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: 278 Verified: 127 [45.7%] Polygon Size Versus County Size [32.4%] Average Perimeter Ratio [32.0%] Percentage of Warned Area Verified (15km) [23.1%] Average Storm Based Warning Size [1524 sq km] Probability of Detection(higher is better) [0.86] False Alarm Ratio (lower is better) [0.54] Critical Success Index (higher is better) [0.42]
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