IEM Daily Bulletin for Jun 1 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 01 June 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
May 31 1:11 PM	iem,main	🐛 Properly compute LST for CLI Audit METARs https://mesonet.agron.iastate.edu/json/cli_audit.py?help	Link

Daily Feature

No feature posted

NWS Watch/Warning Summary for 12 AM 31 May 2026 - 12 AM 1 Jun 2026 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	15	0	0	0	0	0	9	0
Svr Tstorm	109	6	0	0	0	3	13	4
Flash Flood	20	1	0	0	1	0	1	---

ARX = LaCrosse, WI DVN = Davenport, IA DMX = Des Moines, IA OAX = Omaha, NE FSD = Sioux Falls, SD

IEM Cow Report

SVR+TOR Warnings Issued: 114 Verified:  44 [38.6%]
Polygon Size Versus County Size            [20.1%]
Average Perimeter Ratio                    [20.9%]
Percentage of Warned Area Verified (15km)  [22.9%]
Average Storm Based Warning Size           [864 sq km]
Probability of Detection(higher is better) [0.86]
False Alarm Ratio (lower is better)        [0.61]
Critical Success Index (higher is better)  [0.36]

IEMBot Social Media Posts

IEMBot can be configured to post messages to a number of social media services. More details: IEMBot Homepage.

Posts yesterday per supported service:

• ATMosphere (bluesky only attm): 1,869
• Mastodon / Fediverse: 9
• Slack: 112
• Twitter/X: 8,963
• HTTP Webhooks: 214
• Weather.IM Jabber Chatrooms: 11,608