IEM Daily Bulletin for Jun 16 2026
daryl herzmann
Iowa Environmental Mesonet Daily Bulletin for 16 June 2026
News
No news is good newsIEM Code Pushes <repo,branch> on Github
| Timestamp | Repository | Message | Link |
|---|---|---|---|
| Jun 15 10:15 AM | iem,main | 🎨 Refactor json calls to use mlib helper | Link |
| Jun 15 10:23 AM | iem,main | ⚡️ Use cached reference object | Link |
| Jun 15 10:31 AM | iem,main | 💚 Fixup! Address codereview | Link |
| Jun 15 11:59 AM | iem,main | 🎨 Use sql_helper and better parameterized queries | Link |
| Jun 15 12:55 PM | iem,main | ✨ Compute/use daily min,max soilt4 nldas,era5land | Link |
| Jun 15 1:49 PM | iem,main | 🎨 Improve dl robustness and debug logging | Link |
| Jun 15 2:06 PM | iem,main | 📝 Sundry cleanups per log review | Link |
| Jun 15 3:09 PM | iem,main | 🐛 Fixup! param provision to cow from recent change | Link |
| Jun 15 3:11 PM | iem,main | 🐛 Fix close | |
| Link | |||
| Jun 15 3:22 PM | iem,main | ✏️ Fix typo | Link |
| Jun 15 3:37 PM | iem,main | 💚 Update test with updated pyiem | Link |
| Jun 15 5:55 PM | iem,main | 📝 Adjust overflow-x on display | Link |
| Jun 15 2:49 PM | pyiem,main | 🎨 Account for FastAPI usage of ListOrCSVType | Link |
| Jun 15 2:55 PM | pyiem,main | 🎨 Address codereview | Link |
| Jun 15 10:50 AM | iem-database,main | 🐛 Fix sequence perms | Link |
| Jun 15 10:50 AM | iem-database,main | ⬆️ Update precommits | Link |
| Jun 15 10:58 AM | iem-database,main | 📝 Disable sqlfluff rule PG01 for now | Link |
| Jun 15 10:59 AM | iem-database,main | ✨ Add climatology storage of soil degree days | Link |
| Jun 15 11:11 AM | iem-database,main | 🐛 Define srad for ncdc_climate71 for consistency | Link |
| Jun 15 12:04 PM | iem-database,main | ✨ Add {nldas,era5land}_soilt4_{min,max} storage | Link |
| Jun 15 2:24 PM | iem-web-services,main | ⬆️ Update ruff precommit | Link |
| Jun 15 3:02 PM | iem-web-services,main | ✨ Allow CSV params to Cow API | Link |
Daily Feature
Thursday's Wake Low
Date: 15 Jun 05:30 AM
Votes: Good: 11
Bad: 0 Abstain: 0
While the numerous rounds of severe weather last week may be a bit of blur, folks in Ames likely remember the damaging winds from Thursday morning. It was an interesting storm as most of the damage happened after the initial gust front blew through and was associated with a "wake low". The featured chart presents one minute interval observations from the Ames Airport and nicely shows the wake low signature. The top panel shows air and dew point temperature. The second panel combines wind speed, gust, and direction. The bottom panel shows pressure altimeter. A wake low is a transient area of reduced pressure in response to processes happening within organized complexes of storms. These are paired with "meso highs" associated with the gust front and so create strong pressure gradients that generate strong winds. The three panels nicely tell the story of the initial gust front passage (rapid drop in temperature, increase in winds and pressure) followed by a brief lull and subsequent drop in pressure, temperature, and increase in wind speed. The period between about 8 AM and 8:45 AM saw sustained winds near 30-40 MPH with frequent gusts between 50 and 60 MPH. The white dots show the wind direction from the NE during this time, which is likely a strong reason why these winds were damaging. The vast majority of Iowa's strong winds are from the westerly direction, so vegetation and structures "get used to this" situation. When strong winds come from an unique direction, this creates damage possibilities perhaps not possible with strong winds from the west. There is a lot to nerd-out with, but will denote one more interesting item. The minimum plotted temperature reached 59°F just before the wake low departed. Environmental dew points were roughly in the mid 60s, so such a relatively cold temperature was another sign of the strength of the storm complex as thermal and dynamical processes chill the air.
The featured media can be generated on-demand here
.NWS Watch/Warning Summary for 12 AM 15 Jun 2026 - 12 AM 16 Jun 2026 CDT
| Summary | By WFO | Watches | ||||||
|---|---|---|---|---|---|---|---|---|
| Type | US | IA | ARX | DVN | DMX | OAX | FSD | US |
| Tornado | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Svr Tstorm | 40 | 0 | 0 | 0 | 0 | 0 | 3 | 0 |
| Flash Flood | 49 | 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: 39 Verified: 12 [30.8%] Polygon Size Versus County Size [21.3%] Average Perimeter Ratio [21.8%] Percentage of Warned Area Verified (15km) [8.3%] Average Storm Based Warning Size [2844 sq km] Probability of Detection(higher is better) [0.54] False Alarm Ratio (lower is better) [0.69] Critical Success Index (higher is better) [0.24]
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