January 2025 EZNews
- Dr. Scott Dennstaedt
- Jan 2
- 5 min read
Updated: Apr 20
Hello and Happy New Year! Thank you for taking the time to read the 45th issue of EZNews!
We value those members who have chosen to enable automatic renewal of their EZWxBrief membership on a monthly basis. If you haven't done so, please sign in and visit the User Profile page and click on the Renew button. By doing this, you can establish your monthly renewal with a Visa, MasterCard, or Discover credit card. This ensures that you remain connected and continue to enjoy the simplicity of EZWxBrief all year long.
Are you new to EZWxBrief?
For members new to EZWxBrief, you won't find EZWxBrief in the App Store or Google Play Store. For the best user experience, EZWxBrief is optimized to run as a progressive web app (PWA) and must be installed on your device which takes less than 10 seconds per device. Follow the instructions in this video or visit the 180+ page Pilots Guide for more information on how to install EZWxBrief as a PWA on all of your devices. For example, here's how to install EZWxBrief on your iPhone or iPad...it's that EZ!
Buckeye Air Fair presentation
Are you planning to attend the Buckeye Air Fair in Arizona February 14th through February 16th? If so, stop by and say hello. We'll be at the SiriusXM Aviation booth (Booth #1) during the show. Dr. Scott Dennstaedt will be doing a presentation on datalink weather Friday, February 14th at 1 pm and will be happy to answer any questions you might have. We hope to see you there!
Skew-T log (p) diagram options
Due to the recent retirement of NOAA's interactive site, rucoundings.noaa.gov discussed in this blog post, the most frequently asked question over the last eight weeks has been, "What other options are available to build a Skew-T log (p) diagram for an airport?" Listed in The Skew-T log (p) and Me: A Primer for Pilots softcover and eBook are several websites that provide access to Skew-T diagrams. Listed are several sites that provide access to the latest radiosonde observations (RAOBs) that include -
These sites above are strictly to display the temperature, humidity and wind data as a function of pressure from the latest weather balloon launches throughout the U.S. and neighboring countries. There are dozens of websites and apps that provide access to forecast soundings through data from numerical prediction models. A few of these include -
All of these require that you first choose a forecast model such as the Global Forecast System (GFS). Once the model's forecast map is rendered in the window, simply click on the map and the Skew-T diagram for that time and location will be displayed. All three of these sources provided the capability to step back and forth through different valid times based on the model selected. In some cases, the website provides the ability to enter a latitude/longitude or airport identifier as shown below for Tropical Tidbits.
Another website that has gotten a fair amount of recent press is https://flytheweather.com. The interface is a bit clunky, but you have two options that include generating forecast soundings for an airport (Single Location) or along a direct great circle route of flight (Flight Plan).
For the former, you can enter an airport identifier in the upper-left field labeled Departure/Single along with a departure date and time and click on the Single Location button to generate the forecast sounding for that airport at the time selected. For more than just a single forecast at the departure date/time selected, you can also modify the field that is labeled Number of Charts. This will allow you to generate the diagram for the selected departure date/time plus hourly "forecasts" for the number of charts entered.
The second option is to generate a series of diagrams along a particular route. After entering departure and destination airport identifiers along with a departure time, you must also enter the estimated time in route (duration) in hours and minutes. Then when clicking on the Flight Plan button it will generate the forecast soundings that correspond to the departure airport valid at the departure time and at the destination airport at the expected arrival time. To see other equidistant points along the route, you can modify the Number of Charts field which will generate forecast soundings at these points along with the departure and destination airports. For example, entering 6 will provide forecast soundings for the departure and destination airports along with four other equidistant points as shown below.
There are some concerns with this site. All of the temperature, dewpoint and wind data is provided through the https://open-meteo.com API. There is no way to determine which numerical weather prediction model is being used and if the "forecast" sounding is truly a forecast or the analysis from the model.
More importantly, the diagrams for airports or locations along the route include a gray mask at the base of the diagram that represents the elevation of the airport or location. For example, in the forecast sounding above, the airport represented is KTRK (Truckee, California). Truckee's elevation is 5,895 ft MSL based on this site's tabular display (note that the surveyed airport elevation for KTRK is actually 5904.3 ft). So this mask extends from the base of the diagram up to approximately 6,000 feet. Some forecast models (such as the GFS) will provide temperature, dewpoint and wind data below the airport's elevation down to 1000 mb. This elevation mask is designed to "cover up" that data that is essentially below the elevation of the airport.
However, the surface-based parcel lapse rate shown in purple is using the temperature and dewpoint based on the 1000 mb level and not the "surface" conditions. This will result in an incorrect parcel lapse rate and an incorrect lifted condensation level (LCL). This may also provide an incorrect surface-based Convective Available Potential Energy (CAPE) and surface-based Convective Inhibition (CIN) if they are based on the incorrect surface-based parcel lapse rate.
Finally, EZWxBrief is developing a feature that will provide the Skew-T diagrams once again in the Airport Wx view. This will likely be released sometime during late Spring or early Summer 2025 and will contain features extremely useful to pilots not found on any of these other sites.
EZWxBrief v2 news
EZWxBrief v2.0.3 is the current version. There have been no new releases at this point in time. However, we have extended the GFS static weather imagery to 7 days so that it coincides with the extended-range prog charts and the 12-hour Probability of Precipitation (PoP) forecasts.
Most pilots are weatherwise, but some are otherwise™
Dr. Scott Dennstaedt
Weather Systems Engineer
Founder, EZWxBrief™
CFI & former NWS meteorologist
Comments