Iowa Environmental Mesonet Daily Bulletin for 17 June 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp Repository Message Link
Jun 16 10:40 PM iem,main 🐛 Fix when MADIS processing failsback to HTTP Link
Jun 16 10:41 PM iem,main 🎨 Improve logging Link
Jun 16 11:12 PM iem,main 🔥 Drop unused lxml python dep Link
Jun 16 11:28 PM iem,main 🎨 Sundry updates per review Link
Jun 16 11:46 PM iem,main 💚 Address codereview Link
Jun 17 5:36 AM iem,main 💚 Fixup! return dict Link
Jun 17 5:58 AM iem,main 💚 Reduce mpl tolerance with test Link
Jun 17 6:49 AM iem,main 💚 Update mpl test with matplotlib 3.11 Link


Daily Feature

Coolest Day of June
Date: 16 Jun 05:30 AM
Votes: Good: 8   Bad: 0 Abstain: 1

For mid June, the past few days have seen rather crisp temperatures with overnight lows dropping into the 40s over some Iowans and comfortable highs in the 70s. For Des Moines, the coolest daily high temperature for June happened on Sunday (72°F) and coolest low (53°F) on Monday. The featured chart looks into the frequency of a given day of June having either the coolest high or low temperature for the month of June during a given year. While there is certainly a decreasing trend in frequency as the month progresses, such dates can happen any date of the month. The near term forecast does not have much in the way of significant heat.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 16 Jun 2026 - 12 AM 17 Jun 2026 CDT

Summary By WFO Watches
Type USIA ARXDVNDMXOAXFSD US
Tornado 11 0 0 0 0 0 0 0
Svr Tstorm 108 0 0 0 0 0 0 1
Flash Flood 36 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: 118 Verified:  51 [43.2%]
Polygon Size Versus County Size            [25.0%]
Average Perimeter Ratio                    [21.2%]
Percentage of Warned Area Verified (15km)  [24.5%]
Average Storm Based Warning Size           [1086 sq km]
Probability of Detection(higher is better) [0.81]
False Alarm Ratio (lower is better)        [0.57]
Critical Success Index (higher is better)  [0.39]

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