IEM Daily Bulletin for Dec 27 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 27 December 2025

News

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Daily Feature

Foggy Christmas
Date: 26 Dec 05:30 AM
Votes: Good: 9   Bad: 0 Abstain: 0

While temperatures were mild for Christmas, the high end of the forecast temperature range leading up to Thursday failed to materialize due to persistent fog and moisture trapped near the surface. Much of the state was under a Dense Fog Advisory for Christmas Day, including Des Moines. The featured chart presents a time series of horizontal visibility observations from the Des Moines Airport along with the highlighted period covering the issued Dense Fog Advisory for Polk County. The hope is that a larger portion of the state can shake free of the fog on Friday and thus experience at least one very warm day before temperatures drop again on Sunday along with a chance of snow.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 26 Dec 2025 - 12 AM 27 Dec 2025 CST

	Summary		By WFO					Watches
Type	US	IA	ARX	DVN	DMX	OAX	FSD	US
Tornado	0	0	0	0	0	0	0	0
Svr Tstorm	1	0	0	0	0	0	0	0
Flash Flood	2	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:   1 Verified:   1 [100.0%]
Polygon Size Versus County Size            [24.1%]
Average Perimeter Ratio                    [11.3%]
Percentage of Warned Area Verified (15km)  [13.3%]
Average Storm Based Warning Size           [5592 sq km]
Probability of Detection(higher is better) [0.67]
False Alarm Ratio (lower is better)        [0.00]
Critical Success Index (higher is better)  [0.67]