Iowa Environmental Mesonet Daily Bulletin for 04 June 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp Repository Message Link
Jun 3 1:06 PM iem,main ๐ŸŽจ Use updated pyiem TELEMETRY class Link
Jun 3 2:01 PM iem,main ๐ŸŽจ Rectify SPC/WPC Outlook download backend
https://mesonet.agron.iastate.edu/cgi-bin/request/gis/outlooks.py?help
Link
Jun 3 10:09 PM iem,main โœจ Add tool listing VTEC events by SPC/WPC Outlook
A WIP to get feedback.
frontend: https://mesonet.agron.iastate.edu/nws/outlook_and_vtec/
backend: https://mesonet.agron.iastate.edu/json/outlook_and_vtec.py?help
Link
Jun 3 10:28 PM iem,main ๐Ÿ’š Address codereview Link
Jun 4 5:37 AM iem,main ๐Ÿ› Ensure valid delimiter is provided Link
Jun 4 6:39 AM iem,main ๐Ÿšง Iterate on outlook+vtec app
add overlaps, fix dates, fix SQL join
Link
Jun 3 11:31 AM pyiem,main ๐ŸŽจ Validate webutil.TELEMETRY with pydantic Link
Jun 3 11:38 AM pyiem,main ๐ŸŽจ (codereview) Use pydantic type IPvAnyAddress Link
Jun 3 11:52 AM pyiem,main ๐ŸŽจ Use IPvAnyAddress and prevent null bytes Link
Jun 3 12:30 PM pyiem,main ๐Ÿ’š Increase determinism of test Link
Jun 3 12:48 PM pyiem,main ๐ŸŽจ Sundry tweaks attempting to isolate flappy test Link
Jun 3 3:55 PM iem-database,main ๐Ÿงช Add cwa baseline data for testing Link
Jun 3 4:07 PM iem-database,main ๐Ÿงช Include all DMX FF.W for 2024 Link
Jun 3 4:20 PM iem-database,main ๐Ÿงช Add May 2024 Outlook data Link
Jun 3 12:56 PM iem-web-services,main ๐Ÿšš Use updated TELEMETRY class Link


Daily Feature

Cedar Rapids vs Ames
Date: 03 Jun 05:30 AM
Votes: Good: 9   Bad: 0 Abstain: 0

The featured chart compares yearly precipitation totals between Cedar Rapids and Ames. Blue bars indicate Cedar Rapids was wetter than Ames by the given margin and red bars indicate Ames was wetter. This chart nicely shows the variability that exists on the yearly time scale between two sites that have an overall average difference of just 0.37 inches (~1% of the yearly total). There have been just under 20 years with the difference between the two sites over 10 inches (~30% of the yearly total). The overall frequencies of which site is wetter is not that much different with Ames only have six more such years. This just goes to show how variable precipitation can be over even considerable periods of time.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 3 Jun 2026 - 12 AM 4 Jun 2026 CDT

Summary By WFO Watches
Type USIA ARXDVNDMXOAXFSD US
Tornado 2 0 0 0 0 0 0 1
Svr Tstorm 66 0 0 0 0 0 10 0
Flash Flood 18 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:  68 Verified:  17 [25.0%]
Polygon Size Versus County Size            [12.1%]
Average Perimeter Ratio                    [22.5%]
Percentage of Warned Area Verified (15km)  [15.5%]
Average Storm Based Warning Size           [928 sq km]
Probability of Detection(higher is better) [0.57]
False Alarm Ratio (lower is better)        [0.75]
Critical Success Index (higher is better)  [0.21]

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