IEM Daily Bulletin for Feb 14 2026
daryl herzmann
Iowa Environmental Mesonet Daily Bulletin for 14 February 2026
News
Title: Tracking TAF Amendments
Date: 13 Feb 10:28 AM
Author: Daryl Herzmann
link
One of the seemingly unique archives maintained by the IEM is one of NWS Terminal Aerodome Forecasts (TAF)s. An example TAF looks like so:
FTUS42 KFFC 131551 AAB
TAFATL
TAF AMD
KATL 131551Z 1316/1418 09007KT P6SM FEW250
FM140000 12003KT P6SM SCT250
FM141600 14005KT P6SM SCT150=
A user of this archive requested the tracking of "Amendment" status, which the IEM was previously not doing. In the example above, this is denoted as TAF AMD. Support for this was added, but it will take a few days to reprocess the archive to include this attribute within the download service and various web services. Whilst adding web service support for this, the taf overview got some interesting updates and this news item intends to advertise those changes.
Newly supported TAF overview request examples
Provide GeoJSON of all most recently issued TAFs valid at 12 UTC on 25 Dec 2025
https://mesonet.agron.iastate.edu/api/1/nws/taf_overview.geojson?at=2025-12-25T12:00:00Z
This would return the most current issued TAF at or prior to the given UTC timestamp.
Provide JSON of available TAFs for Des Moines during July 2012.
https://mesonet.agron.iastate.edu/api/1/nws/taf_overview.json?station=KDSM&sts=2012-07-01&ets=2012-08-01
This returns all TAF metadata that can be used for subsequent queries to get an individual TAF.
Provide a CSV of all available TAFs for 15 December 2021 (UTC)
https://mesonet.agron.iastate.edu/api/1/nws/taf_overview.txt?sts=2021-12-15&ets=2021-12-16
Requests like these are limited to a 10 day period. The response seqnumber value orders the TAFs descending in time for a given station.
Hopefully folks find this useful and please always send bug reports and feedback our way!
IEM Code Pushes <repo,branch> on Github
| Timestamp | Repository | Message | Link |
|---|---|---|---|
| Feb 13 9:04 AM | iem,main | ⬆️ Update ruff precommit | Link |
| Feb 13 9:20 AM | iem,main | ✨ Support is_amendment in TAF download #1514 | Link |
| Feb 13 1:01 PM | iem-database,main | 📝 Apply sqlfluff some more | Link |
| Feb 13 1:01 PM | iem-database,main | ⬆️ Update ruff precommit | Link |
| Feb 13 8:20 AM | iem-web-services,main | ⬆️ Update ruff | Link |
| Feb 13 8:22 AM | iem-web-services,main | 🎨 Gitignore coverage.xml | Link |
| Feb 13 9:01 AM | iem-web-services,main | ✨ Improve TAF services with admendment and archive refs akrherz/iem#1514 |
Link |
Daily Feature
2026 Daily Min Mixing Ratio
Date: 13 Feb 05:30 AM
Votes: Good: 11
Bad: 0 Abstain: 0
When most folks talk about humidity, it is discussed in terms of dew point temperature or relative humidity. While both of those humidity measures can be useful, they sometimes can be difficult to contextualize. For example, on a 90°F air temperature day most folks would say that a 80°F dew point temperature is more understandably worse than a 75% relative humidity (the two values are approximately equivalent). Anyway, an absolute measure of humidity irrespective of temperature is to compute the ratio of mass of water to the mass of everything else in the air. This is typically expressed in units of grams of water per one kilogram of air. The featured chart presents the period of record climatology of daily minimum mixing ratio for Ames. The top panel shows the shaded region between the min and max observed range with the blue line representing a simple average. The red line plots the 2026 values with the bottom panel plotting the difference between the two. You may recall how incredibly dry the air felt toward the end of January (cracked skin and static shocks from everything you touch within the home). The plot nicely shows how close to zero values got and how far below the meager average departures were during this period.
The featured media can be generated on-demand here
.NWS Watch/Warning Summary for 12 AM 13 Feb 2026 - 12 AM 14 Feb 2026 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 | 9 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Flash Flood | 3 | 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: 8 Verified: 2 [25.0%] Polygon Size Versus County Size [23.2%] Average Perimeter Ratio [8.2%] Percentage of Warned Area Verified (15km) [9.0%] Average Storm Based Warning Size [1764 sq km] Probability of Detection(higher is better) [1.00] False Alarm Ratio (lower is better) [0.75] Critical Success Index (higher is better) [0.25]