IEM Daily Bulletin for Sep 21 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 21 September 2025

News

No news is good news

IEM Code Pushes <repo,branch> on Github

Timestamp	Repository	Message	Link
Sep 21 6:37 AM	iem,main	📝 Sundry updates per review	Link

Daily Feature

No feature posted

NWS Watch/Warning Summary for 12 AM 20 Sep 2025 - 12 AM 21 Sep 2025 CDT

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	0	0	0	0	0	0	0	0
Svr Tstorm	49	0	0	0	0	0	0	0
Flash Flood	13	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:  48 Verified:  13 [27.1%]
Polygon Size Versus County Size            [14.7%]
Average Perimeter Ratio                    [24.2%]
Percentage of Warned Area Verified (15km)  [15.5%]
Average Storm Based Warning Size           [911 sq km]
Probability of Detection(higher is better) [0.56]
False Alarm Ratio (lower is better)        [0.73]
Critical Success Index (higher is better)  [0.22]