IEM Daily Bulletin for Aug 21 2025
daryl herzmann
Iowa Environmental Mesonet Daily Bulletin for 21 August 2025
News
No news is good newsIEM Code Pushes <repo,branch> on Github
| Timestamp | Repository | Message | Link |
|---|---|---|---|
| Aug 20 7:36 AM | iem,main | 🎨 Add editorconfig | Link |
| Aug 20 8:08 AM | iem,main | ✅ Improve coverage | Link |
| Aug 20 2:14 PM | pywwa,main | ⬆️ Update precommits | Link |
| Aug 20 2:22 PM | pywwa,main | 📝 Add more 3166 entries | Link |
| Aug 20 10:26 PM | pywwa,main | 📝 Adjust NHC HDS manual AFOS dump entries | Link |
| Aug 20 11:29 AM | iem-database,main | 🎨 Require AFOS products pil not null | Link |
Daily Feature
Ranking Alert Counts
Date: 20 Aug 05:30 AM
Votes: Good: 11
Bad: 1 Abstain: 0
NWS Des Moines issued a Dense Fog Advisory Tuesday morning as ample near surface moisture and calm winds promoted fog development. The Dense Fog Advisory is one of the more commonly issued alert types as shown the featured chart. The chart shows the top 25 alert types issued by NWS Des Moines since 2009 (a reliable start date for nearly all alert types). The accounting metric used here is the sum the number of counties or zones included within each alert event. For example, the aforementioned advisory covered 29 forecast zones, so that one event would have counted 29 times for this metric. The plotted values are relative to the most frequent alert type, the Severe Thunderstorm Warning. The plot attempts to show a comparable frequency with high end events like Blizzard Warning being much less common than others.
The featured media can be generated on-demand here
.NWS Watch/Warning Summary for 12 AM 20 Aug 2025 - 12 AM 21 Aug 2025 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 | 41 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Flash Flood | 19 | 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: 42 Verified: 19 [45.2%] Polygon Size Versus County Size [20.0%] Average Perimeter Ratio [20.4%] Percentage of Warned Area Verified (15km) [16.4%] Average Storm Based Warning Size [1906 sq km] Probability of Detection(higher is better) [0.60] False Alarm Ratio (lower is better) [0.55] Critical Success Index (higher is better) [0.35]