IEM Daily Bulletin for Oct 4 2025

[daryl herzmann]

Iowa Environmental Mesonet Daily Bulletin for 04 October 2025

News

No news is good news

IEM Code Pushes <repo,branch> on Github

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Daily Feature

Forecasted Cool Down
Date: 03 Oct 05:30 AM
Votes: Good: 9   Bad: 1 Abstain: 0

The National Weather Service produces a number of weather forecast products. One of those is called Model Output Statistics (MOS), which attempts to provide a bias-corrected and point specific forecast based on raw model output. The IEM processes the MOS text bulletins and offers some tooling for this data along with a download option. The featured chart is another tool in this space and plots the combination of morning low and afternoon high observations (dots) along with the time-lagged ensemble range of forecast values for the Ames Airport. In this case, the "GFS Extended" MOS product is plotted. The forecast trend is rather clear with cooler weather arriving to start off next week and lows even perhaps dipping into the 30s by later in the week. Could we perhaps finally be done with summer like heat?

The featured media can be generated on-demand here

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NWS Watch/Warning Summary for 12 AM 3 Oct 2025 - 12 AM 4 Oct 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	1	0	0	0	0	0	0	0
Flash Flood	0	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:   0 [0.0%]
Polygon Size Versus County Size            [7.3%]
Average Perimeter Ratio                    [5.3%]
Percentage of Warned Area Verified (15km)  [0.0%]
Average Storm Based Warning Size           [756 sq km]
Probability of Detection(higher is better) [0.00]
False Alarm Ratio (lower is better)        [1.00]
Critical Success Index (higher is better)  [0.00]