IEM Daily Bulletin for Oct 24 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 24 October 2025

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Daily Feature

Freeze Warning
Date: 23 Oct 05:30 AM
Votes: Good: 12   Bad: 1 Abstain: 0

After sub-freezing temperatures were observed over northern Iowa on Wednesday morning, it is much of the rest of Iowa's turn this Thursday morning to terminate the growing season. The featured map presents counties under a Freeze Warning by the NWS at the time of this feature posting Thursday morning. Many counties to the south of the shown warning are under a Frost Advisory, which covers more marginal freezing temperature conditions. The Freeze/Frost NWS headlines can be a bit confusing this time of year as they are one-time products and can have local office variances on when they will be issued after assessments are made of previous freezing temperature events. For example, you don't see a Freeze Warning over the areas of northern Iowa that had such temperatures on Wednesday morning. Once the growing season is believed to be done for a county, there are no subsequent headlines issued for future events during the fall season.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 23 Oct 2025 - 12 AM 24 Oct 2025 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	33	0	0	0	0	0	0	0
Flash Flood	6	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:  32 Verified:   9 [28.1%]
Polygon Size Versus County Size            [19.2%]
Average Perimeter Ratio                    [16.5%]
Percentage of Warned Area Verified (15km)  [14.4%]
Average Storm Based Warning Size           [1222 sq km]
Probability of Detection(higher is better) [0.90]
False Alarm Ratio (lower is better)        [0.72]
Critical Success Index (higher is better)  [0.27]