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June 2023 EZNews

Hello and thanks for reading the 26th edition of EZNews!

We really appreciate those that have recently joined, renewed their annual membership or signed up for auto-renewal. A big thanks goes out to Timothy F., William P., and Peter B. who renewed for $100, Fabio S. who renewed his annual membership for $120 and Aldo W. who renewed for $150! We truly appreciate your generosity which helps support our continued innovation and growth moving forward. 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 link above or see the 140+ page Pilots Guide for more information on how to install EZWxBrief as a PWA on all of your devices.


Special pricing on The Skew-T log (p) and Me


Due to a slight printing imperfection on the front cover (that is barely noticeable), we are selling The Skew-T log (p) and Me: A Primer for Pilots softcover at a 40% discount. This is a limited time offer, so order your copy today while supplies last.


New "Who's who in aviation & weather" YouTube series


We are excited to tell you about a new program to bring you the latest news and insights from the top minds in the aviation and weather industries. Each month with a focus on weather, we'll feature interviews with leading experts on topics such as air traffic control, flight safety, forecasting, and more. We'll also explore the latest trends and developments in these fields, and provide you with the information you need to stay ahead of the curve. So join us each month as we explore the latest news and trends in these two fascinating industries.


The program will cover a wide range of topics, including:

  • Aviation safety

  • Weather forecasting and analysis

  • Air traffic control

  • General aviation and airline operations

  • Atmospheric science

  • Accident analysis

  • ...and more


The first interview will be in June with Captain Doug Morris who has written several books that includes Pilot Weather: From Solo to the Airlines, a book he co-authored with Dr. Scott Dennstaedt, founder of EZWxBrief. Doug has unique qualifications of being both a meteorologist and the captain of a Boeing 787 for Air Canada. We will ask Doug about his experience flying the 787 to locations all over the world and how he deals with weather from preflight to landing.


How to watch


The program will be hosted live on EZWxBrief's YouTube channel. If you cannot watch it live, the episode is being recorded and will become available on the same channel shortly after the live broadcast ends. The exact date and time for this first episode is still being determined. This will be announced through this blog and will appear on the EZWxBrief YouTube community page.


NWS Weather Story


Each NWS weather forecast office (WFO) posts a daily "weather story" to their home page usually between 4 a.m. and 6 a.m. local time every morning. This is just a summary of the weather for that WFO's county warning area (CWA). For example, the one below uses an animated GIF (not animated here) to show an upper-level weather system that is expected to move offshore by Tuesday with a simple graphic on the right showing maximum and minimum temperatures and the rain/storm potential for the area.

You can find these posted on each of the NWS WFOs website home pages and sometimes within their social media posts. But given that there are 122 WFOs around the country, the Wilmington, NC WFO has provided a single map that links to all of the NWS weather stories from around the country. Simply visit their weather story page and you'll see a similar map below the Wilmington weather story that has each WFO's story available. Simply zoom in on the area you are concerned and then click on that WFO's story image. Each WFO's story is rather unique and some do a superb job summarizing the weather for the day in that area.


We hear your feedback!


We are grateful for the feedback we have received from EZWxBrief members and continue to strive to make the app more user friendly and intuitive to use. At this point we have been working to build EZWxBrief v2.0 that will have a more intuitive user interface and will have better overall performance and a higher resolution. This will take a few more months to develop and test and we hope to have a new major version of the progressive web app released this coming fall.


For example, below is a peek at the new route profile for version 2.0. The route profile will be utilizing high resolution model forecasts for both winds and temperatures aloft. The wind forecast is presented in a more intuitive way as shown below. Specifically, the headwind/tailwind component are markers colored in a bright red/green circle, respectively, with white numbers that depict the magnitude of the headwind or tailwind component at that location, altitude and time.

Moreover, the aircraft course is shown with a solid magenta arrow (north up). Instead of using a wind barb (which was confusing to many), the wind direction will be depicted by a white arrow that points in the direction the wind is blowing and is also relative to true north. So in the example below, the aircraft course is to the southwest and with a wind from the south-southeast all of the markers are showing a quartering headwind (red).


The isotherms will be contoured in version 2.0 to show a more realistic depiction of the temperature aloft that includes the ability to easily see temperature inversions. This will become more important during the cold season to point out regions where freezing rain aloft may be problematic. Below is an example comparing the isotherms in version 2.0 to the Skew-T log (p) diagram. On this icing view in the route profile, it's easy to see a distinct temperature inversion in the isotherm contours over Lake Superior (right side of the view). The 0°C isotherm is presented in red and makes an inverted S over that area. Picking a point along a route over Lake Superior denoted by the red arrow below, notice there are three freezing levels.

Below is the forecast sounding from the GFS around the same time, you can also see a similar profile in this area. Notice that the environmental temperature line in this 9-hour forecast sounding crosses over the 0°C isotherm three times as well above this point. Although there's no icing expected at this point given the rather dry conditions aloft, it's a good example of the improvements in the route profile view that will be available in version 2.0 when it is officially released.


Come visit us at AirVenture 2023


Hard to believe, but it's that time again! EZWxBrief will have a booth at EAA's AirVenture in Hangar C again this year and we are looking forward to meeting many of you there. Stop by during the event and say hello and get a demonstration of EZWxBrief or attend one of Scott's eight presentations planned throughout the week including an overview of EZWxBrief v2.0 and two presentations on the Skew-T log (p) diagram. So mark your calendar. The complete schedule is still being finalized and will be posted in the July edition of EZNews. So far he is confirmed at 12 p.m. on Monday at the NAFI Professional Development Center (PDC) and will be speaking on "How you can influence the forecast." He is also confirmed to present at the AOPA Pavilion on Friday at 1 p.m. on "Five things you must know about datalink weather." He'll be making a special presentation at EAA's Pilot Proficiency Center as well.


Mark your calendars!


Starting on Tuesday, July 18th, keep an eye out for The Daily EZ Weather Brief, AirVenture edition with live analysis of the weather for anyone planning to fly to the event. The program will be daily with the last episode on Friday, July 21st. The schedule for these episodes will be posted on the EZWxBrief YouTube community page. If you cannot attend live, they will be recorded and will appear in this playlist so they will be easy to find. Don't forget to subscribe to the EZWxBrief YouTube channel (@ezwxbrief) to avoid missing these daily programs. Please spread the word to other pilots on your own social media accounts and to anyone who might benefit from watching these daily videos.


Before you leave the show this year, feel free to stop by the booth during the week and ask Scott to do an overview the weather for your departure out of the Oshkosh area and back to your home base. Lastly, we'll have plenty of The Skew-T log (p) and Me and Pilot Weather books for sale. Looking forward to seeing you in Oshkosh this year!


Convective SIGMET criteria


During the warm season, convective weather has a huge impact on the National Airspace System (NAS). As the amount of usable airspace diminishes an any given day, this ultimately engenders delays in the system. A departure within busy airspace usually means a delay. In the worst-case scenario, ground stops may be levied depending on your route of flight and destination airport. Nevertheless, forecasters at the Aviation Weather Center (AWC) are busy at work issuing advisories to warn pilots of these dangerous convective areas.

A single-cell pulse-type thunderstorm is normally easy to spot in the distance and maneuver around while in flight. In this situation, a deviation around such a cell does not eat into your fuel reserves. However, when thunderstorms become embedded, severe or are dense in coverage within an area or along a line, they are considered a significant en route hazard to aviation. This often requires you to plan a more circuitous route which means carrying extra fuel than if you flew a direct route. It is this case that the forecaster at the AWC will issue a convective SIGMET (WST) to “protect” this airspace by issuing one or more advisories to warn pilots of this threat.


When you hear “convective SIGMET” during your preflight briefing, don't think of it as a forecast for thunderstorms. Instead, think of it as a “NOWcast" of organized convection that may be highly challenging or dangerous to penetrate. These active thunderstorms must meet specific criteria before a convective SIGMET is issued. Areas of widely scattered thunderstorms such as shown in this XM-delivered satellite radar image below are generally easy to see and avoid while in flight and often do not meet convective SIGMET criteria.

Nevertheless, on any particular eight-hour shift a single forecaster at the AWC’s convective SIGMET desk looks at all of the convective activity on a continual basis tha tis occurring throughout the conterminous U.S. On an active convective weather day, this is likely the busiest forecaster on the planet. This forecaster is given the responsibility to subjectively determine if an area or line of convection represents a significant hazard to aviation using these minimum criteria:


a. A line of thunderstorms at least 60 miles long with thunderstorms affecting at least 40 percent of its length.


b. An area of active thunderstorms affecting at least 3,000 square miles covering at least 40 percent of the area concerned and exhibiting a very strong radar reflectivity intensity or a significant satellite or lightning signature.


c. Embedded or severe thunderstorm(s) expected to occur for more than 30 minutes during the valid period regardless of the size of the area.


For reference, 3000 square miles is about 60 percent of the size of the state of Connecticut.


Will an advisory be issued as soon as the convection meets one or more of these criteria? Possibly. A special Convective SIGMET may be issued when any of the following criteria are occurring or, in the judgment of the forecaster, are expected to occur for more than 30 minutes of the valid period.


a. Tornado, hail greater than or equal to 3/4 inch in diameter, or wind gusts greater than or equal to 50 knots are reported.


b. Indications of rapidly changing conditions, if in the forecaster’s judgment, they are not sufficiently described in existing Convective SIGMETs.


However, special issuances are not the norm, especially when there are a lot of convective activity to capture. In most cases, a convective SIGMET is not issued until the convection has persisted and met the aforementioned criteria for at least 30 minutes. Given that these advisories are routinely issued at 55 minutes past the hour, any convection that has not met the criteria by 25 minutes past the hour may not be included in the routine issuance. Consequently, there are times where a dangerous line or area of developing thunderstorms could be present without the protection of a convective SIGMET. All convective SIGMETs will have a valid time of no more than two hours from the time of issuance.

Last but not least, these convective SIGMETs are often coordinated by the forecaster at the AWC with meteorologists at the various Center Weather Service Units (CWSUs) located throughout the country at the various Air Route Traffic Control Centers (ARTCCs). At times, a meteorologist at the CWSUs may issue a Center Weather Advisor (CWA) when building cells are approaching convective SIGMET criteria. The goal is not to duplicate advisories when possible and provide the best guidance for pilots.


Most pilots are weatherwise, but some are otherwise™


Dr. Scott Dennstaedt

Weather Systems Engineer

Founder, EZWxBrief™

CFI & former NWS meteorologist






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