IEM Daily Bulletin for Jul 12 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 12 July 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Jul 11 11:03 AM	iem,main	⬆️ Update precommits	Link
Jul 11 11:03 AM	iem,main	🐛 Address undefined var and add docs	Link
Jul 11 11:08 AM	iem,main	💚 Address codereview	Link

Daily Feature

Friday Funnel Fest
Date: 11 Jul 10:27 AM
Votes: Good: 5   Bad: 1 Abstain: 0
Your email client does not support videos, please follow the link from the title of this feature to view.

After numerous funnel clouds were reported over Iowa on Thursday, Friday saw even more funnel clouds reported with even a few reaching the ground as brief tornadoes. This is a favorable time of year for such events as strong instability, low cloud decks, and weak wind shear allow for updrafts to stretch atmospheric spin into tighter vortices. The featured lapse is from the KCRG-TV webcam at the University of Northern Iowa (Cedar Falls/Waterloo) showing a brief funnel cloud during the afternoon hours on Friday. As a reminder, the IEM attempts to curate interesting webcam lapses of weather onto YouTube with the featured lapse found here. And for those of you that like pretty sunsets, this one from Peosta is for you!

NWS Watch/Warning Summary for 12 AM 11 Jul 2026 - 12 AM 12 Jul 2026 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	93	0	0	0	0	0	0	4
Flash Flood	61	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:  93 Verified:  55 [59.1%]
Polygon Size Versus County Size            [20.8%]
Average Perimeter Ratio                    [21.2%]
Percentage of Warned Area Verified (15km)  [29.4%]
Average Storm Based Warning Size           [1340 sq km]
Probability of Detection(higher is better) [0.70]
False Alarm Ratio (lower is better)        [0.41]
Critical Success Index (higher is better)  [0.47]

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): 2,443
• Mastodon / Fediverse: 27
• Slack: 2,119
• Twitter/X: 11,438
• HTTP Webhooks: 205
• Weather.IM Jabber Chatrooms: 15,469