IEM Daily Bulletin for Sep 16 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 16 September 2025

News

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Daily Feature

Warmest Two Days
Date: 15 Sep 05:30 AM
Votes: Good: 9   Bad: 0 Abstain: 0

It was quite warm for September this past weekend with highs into the 90s for much of the state both days. For Waterloo, a high temperature of 95°F on Saturday was followed by a high of 93°F on Sunday. As measured by average high temperature over a two day period, this was the warmest such period so far this year. The featured chart presents the warmest two days each year for Waterloo. The bottom left panel shows the day of year frequency with participating within such a period. The 13-14 September period this year comes in at the end of the observed range for such an event to occur. While not quite as hot as this past weekend, the warm temperatures will continue throughout much of this week.

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 15 Sep 2025 - 12 AM 16 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	29	0	0	0	0	0	0	0
Flash Flood	9	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:  29 Verified:  11 [37.9%]
Polygon Size Versus County Size            [15.1%]
Average Perimeter Ratio                    [12.7%]
Percentage of Warned Area Verified (15km)  [19.0%]
Average Storm Based Warning Size           [941 sq km]
Probability of Detection(higher is better) [0.60]
False Alarm Ratio (lower is better)        [0.62]
Critical Success Index (higher is better)  [0.30]