IEM Daily Bulletin for Mar 5 2026

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 05 March 2026

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Mar 4 12:05 PM	iem,main	✨ Add iemweb helpers around JSON services	Link
Mar 4 12:05 PM	iem,main	🎨 Use new iemweb helpers in JSON services https://mesonet.agron.iastate.edu/api/	Link
Mar 4 6:08 PM	iem,main	💚 Address get_nav call	Link
Mar 4 1:46 PM	pywwa,main	✅ Add non-repo test around #316	Link
Mar 4 3:38 PM	pywwa,main	🎨 Use upsert approach to workaround #316	Link
Mar 4 2:56 PM	iem-database,main	⬆️ Update ruff precommit	Link
Mar 4 3:17 PM	iem-database,main	🎨 Use unique constraint on current_shef refs akrherz/pyWWA#316	Link
Mar 4 3:31 PM	iem-database,main	🐛 Need to handle nulls	Link

Daily Feature

Second earliest Day 4 15% Outlook
Date: 04 Mar 05:30 AM
Votes: Good: 12   Bad: 0 Abstain: 0

Yesterday, the Storm Prediction Center issued their Day 4 convective outlook and covered much of Iowa with a 15% probability of a severe storm within 25 miles of a given point within the outlook area. It is certainly early in the season for such a risk to include Iowa at four days out as shown by the featured chart presenting the period between the first such risk for Iowa and last risk by year. Only 2022 had an earlier such risk, by one day for 5 March. Unfortunately, you may recall the horrific weather that day with the Winterset EF4 Tornado being the most significant. At the moment, the main tornado threat appears to stay south of Iowa.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 4 Mar 2026 - 12 AM 5 Mar 2026 CST

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	1	0	0	0	0	0	0	0
Svr Tstorm	55	0	0	0	0	0	0	2
Flash Flood	10	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:  56 Verified:  14 [25.0%]
Polygon Size Versus County Size            [23.4%]
Average Perimeter Ratio                    [26.3%]
Percentage of Warned Area Verified (15km)  [12.9%]
Average Storm Based Warning Size           [943 sq km]
Probability of Detection(higher is better) [0.68]
False Alarm Ratio (lower is better)        [0.75]
Critical Success Index (higher is better)  [0.22]

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): 1,644
• Mastodon / Fediverse: 56
• Slack: 1,215
• Twitter/X: 15,551
• HTTP Webhooks: 15
• Weather.IM Jabber Chatrooms: 11,803