Northrop Grumman, I needed something that would challenge my mind, body, and spirit. There were two options on the table. I had just graduated with my master’s degree and was seriously thinking of taking the next leap of faith and earning a doctorate.

But that was quickly overshadowed by my second option—my childhood dream of learning to fly. And I wasn’t disappointed. It did challenge my mind, body, and spirit every step of the way.

What intrigued me the most about learning to fly was that it required mastering many disciplines. In other words, it’s more than just jumping into an airplane and learning stick-and-rudder skills. You have to become entrenched in subjects such as aerodynamics, radio navigation, geography, radio communications, airspace, map reading, legal, medical, and my favorite discipline, meteorology.

Despite my background as a research meteorologist, my aviation weather background was limited when I was a student pilot. So, I was very excited to discover what more I might learn about weather in addition to all of these other disciplines. If you are a student pilot, here are some tips that will help you achieve a good foundation with respect to weather.

It Isn’t Easy

First and foremost, weather is inherently difficult. It’s likely the most difficult discipline to master because of the uncertainty and complexity it brings to the table. Therefore, strive to understand what basic weather reports and forecasts the FAA effectively requires that you examine before every flight. It certainly doesn’t hide it. It’s a fairly short and succinct list that’s all documented in the new Aviation Weather Handbook (FAA-H-8083-28) and the Aeronautical Information Manual (AIM). Ultimately, knowing the nuts and bolts of this official weather guidance will help with your knowledge and practical tests and give you a head start once the ink is dry on your private pilot certificate.

Second, as a student pilot, plan to get your weather guidance from a single and reliable source. Try not to bounce around using multiple sites or apps. There are literally hundreds, if not thousands, of websites and apps that will deliver weather guidance to your fingertips such that you can become overwhelmed with all of the choices, and entropy quickly takes over. Besides, flight instructors love to show off their unique collection of weather apps on their iPhone. Sticking with the official subset of weather guidance will allow you to focus on what matters the most.

• READ MORE: Aviation Weather Center Website Upgrade—the Good, Bad, and Ugly

Once you receive your private certificate, then you can expand the weather guidance you use to include other websites and apps.

The two internet sources that should be at the top of your list include the Aviation Weather Center (aviationweather.gov) and Leidos (1800wxbrief.com). Both of these sites provide the essential weather guidance needed to make a preflight weather decision. Using one or both of these sites will help focus you on the official weather guidance the FAA demands you use.

Categorize Your Data

Third, when you look at the latest weather guidance, take a minute and characterize each product. It should fall into one of three categories: observational data, advisories, or forecasts. Knowing its category will tell you how to properly utilize that guidance. For example, if you come across a visible satellite image, that’s an example of observational data.

Observational data is always valid in the past and typically comes from sensors. What about a ground-based radar mosaic (e.g., NEXRAD)? That’s also an observation. Pilot weather reports (PIREPs) and routine surface observations (METARs) are also considered observational data. While not a pure observation, the latest surface analysis chart that is valid in the recent past will identify the major players driving the current weather systems.

• READ MORE: What Is the Criteria for Issuing a Convective SIGMET?

Observations are like the foundation when building a house. All other weather guidance you use will build on that foundation. A sturdy and well-built foundation is the key to a good preflight weather briefing. You can’t know where the weather is going until you know where it has been. Identifying the latest trends in the weather through the use of these observations is the cornerstone of this foundation. When possible, looping the guidance over time will expose these trends. Is the weather moving or stagnant? Is it strengthening or weakening over time?

Advisories such as the initial graphical AIRMETs (G-AIRMETs) snapshot, SIGMETs, and center weather advisories (CWAs) are the front lines of aviation weather. They are designed to highlight the current location of the truly ugly weather. Advisories build the structure that sits atop of this foundation. Essentially, these advisories summarize the observational data by organizing it into distinct hazards and areas of adverse weather to be avoided.

Forecasts are the springboard for how these observations and advisories will evolve over time. You can think of forecasts as the elements that protect the finished house, such as paint, shingles, and waterproofing. This also includes the alarm and surveillance system to alert you to the possible adverse weather scenarios that may occur during your flight. While forecasts are imperfect, they are still incredibly useful. Forecasts include terminal aerodrome forecasts (TAFs), convective outlooks, prog charts, and the remaining four snapshots for G-AIRMETs.

Dive into the Details…

Fourth, details matter quite a bit. Look at the guidance and identify what stands out. Don’t make a decision too early. Instead, carefully observe and gather facts. Is the precipitation occurring along the route limiting the ceiling and/or visibility? Is the precipitation expected to be showery? This is a clear indication of a convective process in place.

Are the surface observations reporting two or three mid- or low-level cloud layers? Again, this is another indication of a convective environment. This can be especially important to identify, especially when there’s a risk of thunderstorms that have yet to form.

…But Fall Back on the Big Picture

Fifth, get a sense of the big weather picture. This is likely the most difficult aspect of learning how to truly read the weather. Think about the big weather picture as the blueprint for building an entire community. It’s what brings everything together. When I do my own preflight briefings, my decisions are largely driven by what’s happening at that synoptic level.

Lastly, read, read, and read some more. Focus mostly on the weather guidance and less on weather theory. These are the specific weather products mentioned earlier. Weather theory is something you can tackle at a later time. The FAA’s Aviation Weather Handbook is a great start. You can download a PDF document for free from the agency website and add this to your online library. This was issued in 2022 to consolidate the weather information from six FAA advisory circulars (ACs) into one source document. My book, Pilot Weather: From Solo to the Airlines, was published in 2018 and is written for pilots at all experience levels in their journey to learn more about weather.

If you fly enough, you will eventually find yourself in challenging weather. The goal of any preflight weather briefing is to limit your exposure to adverse conditions, and that takes resources and time. Once you’ve mastered the weather guidance, then giving Flight Service a call at 1-800-WXBRIEF will allow you to sound like a true professional.

Yes, I eventually did earn that doctorate, but I am really happy that I took the step over 25 years ago to learn to fly. One guarantee with weather: You can never learn enough. I am still learning today.

This column first appeared in the March 2024/Issue 946 of FLYING’s print edition.

The post How to Wrap Your Head Around Weather appeared first on FLYING Magazine.

Answer: During the warm season, convective weather has a huge impact on the National Airspace System (NAS). As the amount of usable airspace diminishes on 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 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 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 in this case that an AWC forecaster will issue a convective SIGMET (WST) to “protect” this airspace. 

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 the 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 occurring throughout the conterminous U.S. on a continual basis. On an active convective weather day, they are 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 line of thunderstorms is at least 60 miles long with thunderstorms affecting at least 40 percent of its length.
• An area of active thunderstorms is 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.
• Embedded or severe thunderstorm(s) are expected to occur for more than 30 minutes during the valid period regardless of the size of the area. 

For reference, 3,000 square miles represents 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 a forecaster, expected to occur for more than 30 minutes of the valid period:

• Tornadoes, hail greater than or equal to three-quarters of an inch in diameter, or wind gusts greater than or equal to 50 knots are reported.
• Indications of rapidly changing conditions, if in a forecaster’s judgment they are not sufficiently described in existing convective SIGMETs.

However, special issuances are not the norm, especially when there is 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.

• READ MORE: Surviving Thunderstorms: Cut Your Risk

Last but not least, these convective SIGMETs are often coordinated by an AWC forecaster 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 Advisory (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.

The post What Is the Criteria for Issuing a Convective SIGMET? appeared first on FLYING Magazine.

But wait, is vertical visibility even a legitimate visibility? Actually, it’s a bit of a misnomer and not a true measure of visibility in the traditional sense. Vertical visibility is a close cousin to ceiling. That is, it represents the distance in feet a person can see vertically from the surface of the Earth into an obscuring phenomenon, or what is called an indefinite ceiling. What isn’t obvious is how vertical visibility is determined, and how this is different from a definite ceiling.

It’s arguable that an indefinite ceiling is perhaps the most misunderstood phenomenon reported in a routine (METAR) or special surface (SPECI) observation. Forecasters will add vertical visibility in a terminal aerodrome forecast (TAF) as illustrated in the image below for Bradford Regional Airport (KBFD) in Pennsylvania. Whether this occurs in a METAR or TAF, vertical visibility is coded as “VV” followed by a three-digit height in hundreds of feet above the ground level. For example, you may see “VV002,” which is a vertical visibility of 200 feet. While a definite ceiling can be broken or overcast, a vertical visibility always implies the sky is completely covered. Let’s explore the difference between a definite and indefinite ceiling and the operational considerations.

Automated Observations

In the early days, human weather observers used to employ what were called “pilot balloons” to estimate the ceiling height. Essentially the balloon was launched by the observer and, given the balloon’s known rate of ascent, they watched the balloon enter the base of the clouds and measured the time it took using a stopwatch to determine the ceiling height. Then new technology emerged called a rotating beam ceilometer that measured the height of clouds. While it was more effective than launching a balloon, this method was phased out around 1990 and replaced with the laser beam ceilometer, the technology still widely used today.

The task of walking outside and assessing the height of clouds is generally a thing of the past given that this technology is incorporated into the automated surface observing system (ASOS) or automated weather observing system (AWOS) present at many airports throughout the U.S. The trained observer simply logs in to the ASOS (or AWOS) and makes their observation based on the data gathered and reported by the automated system. Then the observation is edited and augmented by the observer as necessary. Depending on the airport, this process may be completely automated.

In all honesty, making an estimate of the height of the cloud base isn’t the difficult part. What’s difficult is to provide a representative description of the amount of cloud coverage (e.g., few, scattered, broken, or overcast) in the airport’s terminal area. A laser beam that points straight up may easily miss a scattered or broken cloud deck. To alleviate this issue, the automated systems process the data over a given amount of time since clouds are generally moving through the sensor array area. It was found that a 30-minute time period provided a representative and responsive observation similar to that created by a trained observer. The most recent 10 minutes of sky cover and ceiling height are double weighted using a harmonic mean. (A harmonic mean is used in the visibility and sky cover algorithms rather than an arithmetic mean because it is more responsive to rapidly changing conditions such as decreasing visibility or increasing sky coverage/lower ceiling conditions.) In the end, the goal is to provide an observation representative of the airport’s terminal area, which is the area within 5 sm from the center of the airport’s runway complex. Visibility, wind, pressure, temperature, etc., all have their own harmonic means accordingly.

In our everyday experience, we know that many cloud decks observed from the ground have a very well-defined base. For an untrained observer, it might not be a simple task to determine their height. However, it’s easy to pick out where the base of the cloud starts. Even in these cases, the cloud decks may vary in height and multiple cloud layers may exist. Visually, that may be more difficult to discern for the untrained eye, but automated systems do a reasonable job making that observation. In a convective scenario, it is not unusual to see multiple scattered and broken cloud heights. For example, at the West Michigan Regional Airport (KBIV) the following was observed:

KBIV 122353Z AUTO 08011KT 4SM RA BR FEW011 SCT048 OVC065 19/18 A2972

This observation includes three definite cloud layers, which are a telltale sign that a convective environment is in place even before the first lightning strike.

Nuts and Bolts

An ASOS continuously scans the sky. To determine the height(s) of the clouds, the backscatter returns from the ceilometer are put into three different bins. When there’s a “cloud hit,” the system identifies a well-defined and sharp signature pattern that you’d expect with the sensor striking the cloud base. Essentially this means most of the hits are aggregated around a particular height above the ground. Such a sharp signature is then incorporated into the 30-minute sky cover and cloud height harmonic average, and a new observation is born.

On the other hand, a “no hit” is recorded when there isn’t an ample amount of backscatter received, usually because there are no clouds below 12,600 feet agl over the sensor. Note that the ASOS (and AWOS) is designed only to detect clouds below 12,600 feet above the ground, although a trained observer can and does report higher clouds. Lastly, if the backscatter does not provide that sharp signature around a particular height, an “unknown hit” is recorded. It is this unknown hit that leads us down the path to an indefinite ceiling or vertical visibility.

Haze, Mist, and Fog, Oh, My!

So, isn’t an indefinite ceiling the same thing as a ground fog event? Not necessarily. Stratus is the most common cloud associated with low ceilings and reduced visibility. Stratus clouds are composed of extremely small water droplets or ice crystals (during the cold season) suspended in the air and may be touching the surface, so to speak. An observer along a coastal region or on the side of a mountain would likely just call this plain old fog. This is certainly understandable, since we grew up calling this kind of situation foggy.

Fog, however, is thought to be more of an obstruction to visibility from a surface observing standpoint. To understand the recording of obscurations, here’s how the ASOS automatically determines what to report. Once each minute, the obscuration algorithm checks the reported visibility. When the visibility drops below 7 sm, the current dew point depression (temperature-dew point spread) is checked to distinguish between fog (FG), mist (BR), and haze (HZ). If the dew point depression is less than or equal to 4 degrees Fahrenheit (~2 degrees Celsius), then FG or BR will be reported. Visibility will then be used to further differentiate between FG and BR.

Whenever the visibility is below five-eighth sm, FG is reported regardless of the “cloud” that produces it. So fog isn’t really about a cloud or ceiling as much as it is about visibility. Therefore, stratus and fog frequently exist together. In many cases, there is no real line of distinction between the fog and stratus; rather, one gradually merges into the other. Flight visibility may approach zero when flying in stratus clouds. Stratus over land tends to be lowest during night and early morning, dissipating by late morning or early afternoon. Low stratus clouds often occur when moist air mixes with a colder air mass or in any situation where temperature-dewpoint spread is small.

• READ MORE: Decoding the Weather

Moisture-Rich Environment

Essentially, an indefinite ceiling means there is something obscuring your view of the cloud base. When you look up, you won’t be able to see a well-defined cloud base like you would on a day where the sky isn’t obscured. According to the ASOS User’s Guide, “these ‘unknown hits’ are primarily caused by precipitation and fog that mask the base of the clouds.” The laser beam bounces off moisture at various heights, making it impossible to process this as a definite cloud hit. Instead, the ASOS identifies these unknown hits as a vertical visibility abbreviated as “VV” in the resulting routine or special observation.

Given the broad moisture field near the surface that scatters the laser beam signal, indefinite ceilings are guaranteed to be paired with low visibility situations. You are not going to see a surface visibility of 10 miles paired with a VV of 200 feet. Usually this means a low or very low IFR flight category anytime there’s an indefinite ceiling. Also keep in mind that an indefinite ceiling in a terminal forecast will result in a low visibility forecast.

In general, the higher the vertical visibility, the better the surface visibility. Therefore, a vertical visibility of 200 feet (VV002) is usually met with a visibility of one-half sm. Furthermore, a vertical visibility of 700 feet (VV007) will likely be associated with a visibility between 1 and 2 sm. While rare, you may even see a fairly high vertical visibility over 1,000 feet (e.g., VV012). In this case, the surface visibility may be over 3 sm. The really bad stuff, however, occurs with a visibility of one quarter sm (or even “M1/4 SM” denoting less than that) and a vertical visibility of zero feet (VV000) as illustrated in the image below for Bradford Regional Airport. This very low indefinite ceiling is not all that common unless you are stationed on the summit of Mount Washington in New Hampshire, where this low vertical visibility happens quite often throughout the year. It also occurs fairly often at airports along West Coast regions of the U.S., especially during their “May gray” or “June gloom” time frame.

As mentioned earlier, fog and precipitation are the two primary reasons the base of the cloud deck is obscured. Therefore, it’s common to see vertical visibility reported when light rain, drizzle, or even snow is falling from the cloud base.

Precipitation or not, it’s generally rare to see a single station reporting an indefinite ceiling. Most of the time, you will see indefinite ceiling reports embedded in a widespread area of low or very low IFR conditions, especially at coastal airports. Although airports such as Nantucket Memorial Airport (KACK) in Massachusetts can be reporting a low indefinite ceiling, at stations farther inland near Cape Cod the sky can be clear or nearly so.

It’s important to note that conditions producing an indefinite ceiling often take longer to improve. Normally there will be a transition from an indefinite to definite ceiling once the moisture begins to mix out with the help of the sun. However, the visibility may still be quite low for the next few hours. Keep this in mind when flight planning to an airport reporting an indefinite ceiling.

Operational Significance

From a practical standpoint, you should treat an observation or forecast for a vertical visibility the same as you’d treat a definite ceiling. Given the nature of conditions that produce an indefinite ceiling, you can expect a longer transition as you depart into such a ceiling under IFR. It’s easy to get spatial disorientation because of the gradual change.

An indefinite ceiling restricts the pilot’s flight (air-to-ground) visibility. Therefore, an instrument approach may be a bit more challenging even after you drop below the reported ceiling height because of the reduced visibility. Most importantly, a circle-to-land approach with an indefinite ceiling will make it quite difficult to keep the runway in sight, especially at night. And, as a final consideration, with an indefinite ceiling, don’t be surprised to see runway visual range also pop up in the observation for airports with such equipment.

This feature first appeared in the October 2023/Issue 942 of FLYING’s print edition.

The post Here’s the Lowdown on ‘Vertical Visibility’ appeared first on FLYING Magazine.

• READ MORE: NOAA Changing Weather Site

Overview

A majority of the weather data will appear on the graphical forecasts for aviation (GFA) webpage. This is the heart and soul of the new site. Here’s a brief description of the purpose of this page as posted in the GFA help on aviationweather.gov.  

“The GFA webpage is intended to provide the necessary aviation weather information to give users a complete picture of the weather that may impact flight in the United States (including Alaska & Hawaii), Gulf of Mexico, the Caribbean, and portions of the Atlantic and Pacific Oceans. The webpage includes observational data, forecasts, and warnings that can be viewed from 18 hours in the past to 18 hours in the future. Hourly model data and forecasts, including information on clouds, flight category, precipitation, icing, turbulence, wind, and graphical output from the National Weather Service’s National Digital Forecast Data (NDFD), are available.”

What’s a Progressive Web App?

Let’s begin with the good news. Like my website, EZWxBrief, the Aviation Weather Center (AWC) decided to build its website  as a progressive web app (PWA). The aviationweather.gov legacy site was very clumsy and nearly impossible to use on a mobile device such as an iPhone. Developing this as a PWA offers a very responsive design, and that means it works reasonably well on those smaller hand-held devices in both portrait and landscape orientations. 

No, you won’t find this “app” in the App Store or Google Play Store. Instead, you should install the PWA on your device to have the best user experience. Not to worry, it literally takes just a few seconds and applies to any device, not just handhelds. 

Here’s the installation process. Simply open a browser that supports a PWA such as Chrome, Safari, or Brave and enter “https://aviationweather.gov” into the browser’s address bar. On your hand-held device, locate the “Share” icon (sometimes called a “Bookmark” or “Send to” icon). This is an icon that’s shaped like a square with an upward pointing arrow in the center. Please note that not all browsers support progressive web apps. A tap on that icon and you have finished step one of three to install the app. 

Next, you’ll be shown the “Share” menu. Scan down that menu using Chrome or Safari and tap on the “Add to Home Screen” selection.

During the third and final step, you’ll be able to name your PWA icon. You are free to change the long default name from “AviationWeather.gov” to AWC or whatever you like. When you’ve chosen the name, tap on the “Add” button in the upper-right corner. This will add an Aviation Weather Center icon to your home screen with the name you chose. Even better, when the Aviation Weather Center makes future updates, they will be available the next time you restart the app. It’s actually easier than installing and updating native apps.

Just like any native app, tap on that home screen icon and the aviationweather.gov site will open up. You’ll notice that it doesn’t have any browser bar or other browser controls, which frees up valuable screen real estate on smaller devices. Essentially, it will have the same look and feel as a native app without the overhead of Apple or Google. 

You can do the same installation on your desktop or laptop computer, but the process is a bit different. Once again, open up your browser and type “https://aviationweather.gov” into the address bar, and you will see an Install button appear at the end of the address bar for any website (and browser) that supports a PWA.

Clicking on the “Install” button will provide the prompt below to install the app.  Once done, you’ll see an Aviation Weather Center icon on your desktop. By the way, you can also always uninstall the app at any time for any of your devices.

One of the issues that is apparent with the site on some hand-held devices is that the app will crash or reset when using a rapid, pinch-and-zoom gesture on the interactive GFA map. This is evidently an issue with Leaflet (the software it uses to render the maps), and the workaround is to avoid any rapid, pinch-and-zoom gestures. Just slow your roll and you’ll be fine.  

Cross Section Tool

To replace the Java Flight Path Tool that required you to download Java onto your computer (Java isn’t permitted on iOS devices), the AWC added a cross-section tool that now runs on any platform. You will see an icon on the right to start this tool. It’s the icon just under the settings icon (cog wheel).

You simply define a route, such as KMCI.KMEM.KAVL (note the periods in between the identifiers), and you can plot this path on the GFA map as a great circle route or view it as a cross section. Currently, the only variables you can plot on the vertical cross section are temperature, wind speed, turbulence, and icing.

Reduction in Static Imagery

The overall new design of the website is radically different from its legacy counterpart. Perhaps the most significant long-term effect is that the AWC decided to terminate the generation of dozens of static images that were available on the legacy site. Many flight planning websites, and even some of the heavyweight EFB apps referenced, scraped many of these images off of the AWC site. Consequently, you may have noticed back in the middle of October that these apps had to scramble to delete those from their own static imagery collections. The imagery collections that were depreciated included: 

• Lowest freezing level forecast from the Rapid Refresh (RAP) model
• TCF, eTCF, ECFP convective forecasts
• RAP/NAM Wind/Temperature graphics
• PIREP plots
• Satellite regional plots

Although you can still find access to prog charts, G-AIRMETs, as well as icing and turbulence static imagery within the decision support imagery page (https://aviationweather.gov/graphics), the AWC has a goal to eventually eliminate all static imagery.

Missed Opportunities

Your opinion  may differ, but I find the user interface for the decision support imagery to be very antiquated and clumsy. Even on large screens, you have to constantly scroll up and down, and it requires an immense amount of button clicks or taps to get what you want. It’s very exhausting and tedious to use. In fairness, that page suggests it was “designed for Center Weather Service Unit meteorologists who build information packages on desktop computers.” Instead, AWC suggests that pilots utilize the interactive map page (https://aviationweather.gov/gfa).

The issue here is that the DSS page gives you a vertical resolution of 2,000 feet for icing and turbulence forecasts. If you use its interactive map, you only get a 3,000-foot or even 6,000-foot vertical resolution despite the fact that the native vertical resolution of the icing and turbulence products is 1,000 feet. It is understandable that browsers have hard limitations, and this was likely a tradeoff to providing something that has a reasonable performance. 

While the Aviation Weather Center removed the regional satellite imagery from the site, it has been incorporated as a separate layer into the graphical forecasts for aviation (GFA) tool. Currently there isn’t a replacement for the color infrared satellite imagery. That is something it will be adding in the future.

Another deficiency is that the site doesn’t acknowledge when the layer you are viewing is void of data. For example, if you pull up the center weather advisories (CWAs) on the GFA tool, you may get a blank map. Is the map blank because there are no CWAs active, which happens more often than not? Or perhaps it’s because your browser or internet connection is being finicky? The lack of any data or advisories is just as critical as the presence of them. AWC doesn’t provide any acknowledgement or banner to alert you when this occurs.  

If you are looking to travel outside of the U.S., some of the weather guidance on the GFA tool, such as icing and turbulence, stops at the border. While this was also true with the legacy GFA tool, it still represents a shortcoming given that much of this guidance is available over a good portion of Canada and northern Mexico. The National Weather Service (NWS) has a directive that it can’t show forecasts outside of the U.S., especially over Canada and Mexico. Pilots are supposed to go to the respective website/services for those countries to receive that forecast information.

This is inconsistent since some decision support graphics (i.e., static imagery) clearly show forecasts for icing and turbulence in Canada and Mexico. Moreover, if you plot a route from International Falls, Minnesota, to Caribou, Maine (through southern Ontario and Quebec, Canada), the cross-section view shows this guidance.

Finding HEMS

If you are looking for the helicopter emergency medical services (HEMS) tool, it has been integrated into the interactive GFA and rebranded as the GFA-LA tool (with “LA” for “low altitude”). When viewing the GFA, click on the helicopter button in the upper-right part of the map to switch the GFA from general aviation mode into low-altitude mode, which offers expanded capability from the HEMS tool.

Final Thoughts

There’s no doubt that there are winners and losers with this update. I’ve read hundreds of comments on social media posts and other aviation forums that despise the new site and those that simply love it. The biggest advantage is that the site is very responsive on hand-held devices with the occasional glitch that I’m sure will be resolved in time. The dismantling of nearly half of the static imagery is truly a loss and will likely be felt for months, if not years, to come. As a matter of fact, I am in the process of finding replacements of these image collections for my own website, EZWxBrief. 

Lastly, if you are still hanging onto a glimmer of hope that AWC will bring back the legacy site, don’t hold your breath. While there are still some growing pains with this new version, the Aviation Weather Center is fully committed to this new release—so just get used to it. 

The post Aviation Weather Center Website Upgrade—the Good, Bad, and Ugly appeared first on FLYING Magazine.

The new site has a much cleaner appearance than the legacy site from the Aviation Weather Center arm of NOAA. It features more interactive maps, static images to embed in briefing material, and a dark mode.

User Features

The user can select raw data or, with a push of a button, have it presented decoded.

You can select the most recent weather or take a look as far back as 48 hours, and there is a “remember” feature.

Under the weather tab at the top of the page is a drop-down menu for observations and forecasts for ceiling, visibility, precipitation, thunderstorms, temperature, winds, turbulence, and icing. Each item is indicated with text and an icon.

Clicking on the icons calls up an interactive map with a slider that displays a graphic depiction of the forecast conditions.

According to the agency, the upgrade is designed to be adaptable to permit use on mobile devices.

All displays and tools available on the current aviationweather.gov are available on the updated website. In addition, the new website merges the legacy Helicopter Emergency Medical Services (HEMS) tool into the same framework as the Graphical Forecasts for Aviation while keeping its focus on low-altitude flight.

The Aviation Weather site is a free service and does not require a discreet login or user account. This makes it more accessible as a weather tool. However, unlike products that require a discreet login, the user’s interaction with the site is more difficult to verify.

If you can’t wait until Monday, test out the new features here: https://beta.aviationweather.gov.

The post NOAA Changing Weather Site appeared first on FLYING Magazine.

A. Most of the official aviation weather forecasts you will get on a standard briefing or via your favorite heavyweight aviation app or website are issued by aviation meteorologists located at the Aviation Weather Center (AWC) in Kansas City, Missouri. This includes graphical AIRMETs (G-AIRMETs), SIGMETs (WS) and convective SIGMETs (WST). Terminal aerodrome forecasts or TAFs, however, are not issued by the AWC nor are they issued by Flight Service; they are issued by forecasters physically located at your local NWS Weather Forecast Offices (WFO) throughout the United States and its territories shown below. The meteorologists at the local WFOs are very familiar with any local weather effects and have the best opportunity to produce a quality forecast for aviation. 

Your local WFO typically has the responsibility for issuing the TAFs for six or seven terminal areas on average. At the Greenville-Spartanburg WFO, for example, they issue the terminal forecasts for six airports to include KAND, KGSP, KGMU, KCLT, KHKY, and KAVL.

• READ MORE: Ask FLYING: Why Are Windsocks the Color They Are?

Scheduled TAFs are issued routinely four times a day at 00Z, 06Z, 12Z and 18Z. They are typically transmitted 20 to 40 minutes prior to these times. Once the TAFs hit the wire, the forecaster must continue to compare the forecast to the actual observations for the airport to be sure it accurately depicts the ceiling, visibility, wind, and weather occurring at the airport. When there is a discrepancy or the forecaster feels that the TAF isn’t representative of the weather that may occur in the terminal area within the TAF’s valid period, they will issue what is called an unscheduled TAF, better known as an amendment.   

The forecaster doesn’t literally have to watch the observations minute by minute. In fact, they have a program called Aviation Forecast Prep Software (AvnFPS) that monitors the observations at the respective airports. Based on programmed criteria, the software compares the terminal forecast to the latest observations for each TAF site issued by that forecaster and flags the forecast element as green when they match. When the program highlights a forecast element as yellow or red, this means the difference is near or has exceeded the amendment criteria. As can be seen above, the forecast for the most part matches the current observations for those airports in the Greenville-Spartanburg WFO (most elements are green). However, there are three terminal areas (KAVL, KHKY, and KAND) that show yellow for wind (speed or direction) implying that the forecast is not quite in line with the current observations. This allows the forecaster to quickly scan the display to determine if there is an immediate need for an amendment to one or more of the TAFs they issue. 

Amendments are the absolute best way to provide the highest quality forecast. In general, a forecaster will issue an amendment when it meets specific criteria that are imminent or have occurred and those conditions will, in the forecaster’s estimation, persist for 30 minutes or longer, or new guidance/information indicates future conditions are expected to be in a different flight category than originally forecast, especially in the next one to six hours.

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Just like instrument students are taught by their instructors not to “chase the needles,” forecasters are similarly encouraged not to chase the observations. For example, an unexpected, but brief rain shower may quickly develop and pass by the terminal area temporarily lowering visibility below the visibility in the TAF. The forecaster may be tempted to issue a quick amendment, but if the condition is expected to be brief, there’s no value to issuing an amendment—especially if it doesn’t alter the flight category (i.e., VFR, MVFR, IFR, LIFR) for the airport.  

The following categorical amendment criteria table below defines the thresholds of importance. 

In addition to the categorical amendment criteria above, below are other criteria where an amendment may be necessary. 

Weather

The TAF should be amended if thunderstorms, freezing precipitation, or ice pellets occur and are not forecasted, or, if forecasted, do not occur.

Wind Direction, Speed, and Gusts

The forecast mean refers to the mean wind direction or speed expected for the specified forecast group time period.

• The TAF should be amended if the forecast mean wind speed differs by ≥ 10 knots, while original or newly expected mean wind speed is ≥ 12 knots.
• The TAF should be amended if the forecast wind gust (or forecast of no gust) differs from observed wind gust by ≥ 10 knots (or above the observed mean wind speed if no gusts are forecast).

Non-convective Low-level Wind Shear (LLWS)

The TAF should be amended if non-convective LLWS is forecasted and does not occur, or if LLWS occurs and is not forecast.

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The forecaster that issues the TAFs is assigned to the “short term desk” and has other duties to include the area forecast discussion (AFD) and may also include the issuance of severe thunderstorm or tornado warnings for their county warning area (CWA). The forecaster shown below is located at the Greenville-Spartanburg WFO and has recently transmitted the 1800 UTC scheduled TAFs and is now working on the gridded forecasts for the GSP region. The national gridded forecasts can be found here. The AvnFPS software compares the current observations to the gridded forecasts looking for differences as well.

As mentioned earlier, TAFs are issued at prescribed times every six hours. For the Chicago, Atlanta, and New York City terminal areas, however, TAFs are now issued every two or three hours. The NWS began this about a decade ago as part of an enhanced aviation project for the FAA…and it went over so well that they adopted it permanently. For the Chicago O’Hare airport (KORD), for example, you might even see 2-hourly updates at certain times during the day. The 2-hourly issuance times match the times of the FAA planning conference calls. Unlike other WFOs where forecasters that issue TAFs have multiple duties, these WFOs have a dedicated aviation forecaster. 

Here’s the ugly side of this improvement. The two- or three-hourly forecast is treated as an amended forecast, not a newly constructed TAF. In fact, these non-standard scheduled TAFs will carry the AMD tag when viewed online or via a standard briefing. So, there’s no way to tell if the forecast was changed because the amendment criteria was reached or because it was time for a new forecast. Moreover, you won’t see a new forecast if an amendment has been issued within 90 minutes prior to the next 2- or 3-hour non-standard scheduled forecast. For many pilots, this subtle change won’t cause any significant impact to your current flight planning regiment. If you happen to fly into or out of a busy airspace such as Chicago, Atlanta, or New York, just keep in mind that forecasts will be updated much more frequently even on those not-so-challenging weather days. In the end, if you see a terminal forecast tagged with AMD, it may not be because the previous forecast was misaligned with reality. It simply may be a new and improved forecast for you to ponder.

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Do you have a question about aviation that’s been bugging you? Ask us anything you’ve ever wanted to know about aviation. Our experts in general aviation, flight training, aircraft, avionics, and more may attempt to answer your question in a future article.

The post Are There Any Amendment Criteria for a TAF? appeared first on FLYING Magazine.

But first, let’s take a step back in time. On November 28, 2006, the National Weather Service (NWS) began the process of moving away from a text-based system by standardizing the text that was used in the legacy AIRMETs. This standardization step was necessary to pave the way for the AIRMET to be automatically generated from the operational G-AIRMETs that were being proposed at that time. This was also wrapped up in the plan to retire the aviation area forecast (FA) and officially replace it with the graphical forecasts for aviation (GFA). The retirement of the FA occurred on October 10, 2017. During this standardization stepping stone, the NWS removed specific things from the legacy AIRMET that included, in part:

1. The frequency of the hazard occurrence such as /OCNL/ AND /FRQ/

2. Trend remarks

3. The reason for amending, correcting or canceling an AIRMET

4. SIGMET reference statements such as /FOR AREAS OF POSS SEV TURB/ and /FOR AREAS OF POSS SEV ICE

5. The cause of the turbulence, low-level wind shear, and strong surface winds

6. The icing types such as /RIME/, /MXD/, and /CLR

7. The location of icing with respect to clouds and precipitation such as /ICGICIP, /ICGIC/, and /ICGIP

Although some pilots actually noticed the difference after the standardization occurred and were disappointed that the extra details were removed, most did not. In fact, it’s more likely than not that a majority of pilots still don’t know they are looking at a G-AIRMET versus the legacy AIRMET when the AIRMET is depicted graphically. In fact, this is likely one of the reasons it’s taken this long to retire the legacy AIRMET. It’s still used by many of the various aviation applications, including many of the heavyweight apps. However, the folks at Flight Service (Leidos) have been using G-AIRMETs for quite a while, but still allow a pilot to choose between the G-AIRMET and legacy AIRMET on their website, namely, 1800wxbrief.com.  

• READ MORE: Ask FLYING: What is a G-AIRMET?

Before the plug could be officially pulled, the FAA convened a Safety Risk Management Panel (SRMP) this year to evaluate any pitfalls associated with the retirement of the legacy AIRMET. Based on the working group’s recommendation and the SRMP results, the FAA has requested the NWS retire the legacy AIRMET and transition to only the G-AIRMET for the conterminous U.S. The legacy AIRMETs for Alaska and Hawaii will not be affected at this time and this change will not affect significant meteorological information (SIGMET) advisories in any way. 

The NWS recently released a Public Notification Statement (PNS) that is asking for public comments before it officially retires this product in February. Based on the comments received, the FAA/NWS could push the AIRMET retirement to later in the year. However, the wheels are in motion to stop automatically producing the legacy AIRMET over the six forecast regions of the conterminous U.S. When the legacy AIRMET is officially retired, only G-AIRMETs will remain. Keep in mind that G-AIRMETs are completely graphical and have no textual component, only metadata.   

The post Say Goodbye to the Traditional AIRMET appeared first on FLYING Magazine.

When there is a hurricane or severe weather of any sort, aviation weather websites get a work out.

If you are watching the weather, trying to determine the path of the storm, this national weather report, which can be accessed in just a few keystrokes, may be a helpful resource. 

How To Get It

1. The National Oceanic Atmospheric Administration (NOAA) provides an interactive weather map on its Aviation Weather Center, which may be found here.

Unlike other aviation weather sites, you do not need an account or a password to access this information. It is an excellent supplemental weather tool for pilots, and a valuable site for anyone who wants to check the weather on a global level.

2. Under “Aviation Weather Overview” at the top of the page, click on TAFs (terminal area forecasts). Move down the screen to the line that states: “Manually Select TAF Data.” In this box type @ and then the two letter postal code for the state you are looking for. For example, if you want to see what Hurricane Ian is doing to South Carolina, type: “@SC.”
3. Select the “Include METAR” box, then click on “Get TAF data” and voila! You have the information for all the airports in that state that have reporting weather.

Raw or Decoded

Pilots are required to learn how to read the weather reports in raw format. It’s how the reports appear on knowledge exams. Using the “Decode” function just makes it easier to understand them, if you are not familiar with the FAA’s acronyms.

If you have a copy of the FAR/AIM, you will find Chapter 7 of the AIM has a page I love to call “The Secret Decoder Ring,” because it translates the abbreviations that sometimes don’t make much sense—seriously, who came up with BR (“baby rain”) for mist? (Actually, it is an abbreviation for the French word for mist, brume.)

If you decide to go the raw-data route, remember the reports begin with the airport identifier—and you may have to look those up. For example, KACE is Columbia Metro Airport in South Carolina. 

In the decoded format, the name and location of the airport are included.

Next, the date and time of report issuance (and in the case of a TAF, when the report is valid), followed by the direction the wind is blowing and the velocity. The letter G means “gust” here. If you see PK WND, that is the “peak wind” recorded.

The acronym PRSFR means “pressure falling rapidly,” which typically means a storm is approaching rapidly.

A METAR at an airport is the “what is happening now” part of a weather report. METAR stands for “meteorological aerodrome reports” and usually provides hourly updates of weather within 5 nm/6 sm of an airport.

If the METAR has the acronym SPECI in front of it, that means the weather is changing rapidly and a special report has been issued to reflect that.

The post Weather Check: How To Plan Your Route Around Severe Weather appeared first on FLYING Magazine.