Alaska weather forecast graphics updated

The Alaska Aviation Weather Unit (AAWU) recently upgraded a number of their graphic weather products in ways which makes them easier to use. An arm of the National Weather Service, this unit generates the Area Forecasts, along with SIGMETS and AIRMETS for Alaska. These statewide products help us see the “big picture” regarding where icing, turbulence and poor weather are forecast for the next twelve hours or so, and are found under the GRAPHICAL FORECASTS tab at the AAWU home page:

Select the Icing Forecast, and you will notice something new!

In this 12 hour Icing Forecast Summary, major rivers have been added in blue to provide geographic reference.

In this 12 hour Icing Forecast Summary, major rivers have been added in blue to provide geographic reference.

In the past, other than the outline of the state, pilots have relied on the forecast zone boundaries as the sole means to “navigate” the charts. At least in my experience, at times it has been a challenge to figure out where weather relative to my intended route of flight. While the forecast zones (slightly subdued) are still there, the AAWU added major rivers to the products. For my money, that is a lot more useful feature for geographic reference. Kudos to the AAWU staff for adding these to the Forecast Weather, Icing and Turbulence forecasts! The Surface Chart and Prog Charts remain unchanged.

Better time resolution too!
Not as new, but worth mentioning is that a little more than a year ago the AAWU made a few other changes that make these charts easier to interpret. Instead of a single static map, the graphics now cover twelve hours, and show changes as often as every three hours, when conditions are expected to develop through the forecast period. On a Windows based system, just hover the mouse over the time intervals shown at the top of the frame, and watch the forecast areas change. On my iPad, I have to select each image individually, but the extra information showing how conditions are expected to develop is just what I am looking for. Also notice, the times on at the top of the product are local, as opposed to UTC.

This example product shows forecast icing for the 3 hour period starting at 15:00 local (yellow oval).  Other selections on that status bar would show how conditions were forecast the change during the 12 hour period.

This example product shows forecast icing for the 3 hour period starting at 15:00 local (yellow oval). Other selections on that status bar would show how conditions were forecast to change during the 12 hour period.

For more information on how the graphic products were revised see this earlier article, but for now focus on the addition of the river boundaries. If you have comments, feel free to share them with the AAWU at the following email address: [email protected] NWS appreciates hearing from pilots, as they continue to refine the products we use to figure out when it is safe to fly.

Alaska Aviation Weather Forecast Changes and Enhancements

Update:  Due to the government shutdown, the changes described below have been delayed, and are planned to go into effect on November 12.

The weather is still one of the most important factors we need to evaluate before each flight.  Whether you fly VFR or IFR, knowing the current conditions and how they are expected to change is critical to that all important GO/NO GO decision,  figuring out which route to take, and what to watch for inflight.  On October 15th, the Alaska Aviation Weather Unit (AAWU) will make changes that should help you make those decisions, as you plan to fly.  Here are some of the changes.

Area Forecast/Airmets
Starting in mid-October, new Area Forecasts (FA’s) will be issued three times a day—at 4:15 a.m., 12:15 p.m. and 8:15 p.m., local Alaska time.  Updates will come out at 12:15 a.m., 6:15 a.m. and 6:15 p.m.—or as needed if things are changing faster than anticipated.  AIRMETs will be either issued or updated using a similar schedule, the details of which may be found on the AAWU website at:

Icing and Turbulence Graphics
In a trend which I find helpful, more information is being presented in graphic form.  Starting on Oct 15, the AAWU will issue new icing and turbulence graphics, showing the forecast in three-hour time slices, as opposed to the 6 hour charts we have been using.  Found under the Graphical Forecast tab on their home page, in the sample Icing Forecast product below, the user has a choice of viewing a single 12 hour summary, or on the bar immediately above the product, selecting one of the three-hour charts to see how the forecasters expect conditions to develop during the day.

Sample Icing Forecast Product summarizes over the entire 12 hour period. Individual charts showing 3 hour intervals show how conditions are expected to develop.

Sample Icing Forecast Product summarizes over the entire 12 hour period. Users can select individual charts showing 3 hour intervals to see how conditions are expected to develop.

Another change is that the Turbulence Forecast will be split into separate low and high altitude products.  Along the top, in the sample image below, the user again has the option to look at the 12 hour summary— showing the entire forecast period—or can mouse-over a progression of graphics to see how the turbulence is expected to develop during the forecast period.  Note that while the products are split at Flight Level 180, if conditions span that flight level, they will be depicted on both sets of products.  A little time spent examining the legend to become familiar with the new conventions will help become accustomed to these products.

sample turbulence lo level

Sample low altitude turbulence product, covering a 3 hour period. Users may also select the 12 hour summary chart to get the “big picture.”

A more subtle difference in the product to note:  An additional turbulence category, “Isolated Moderate” is being added. Previously the products only depicted “Occasional Moderate” and “Isolated Moderate to Severe” conditions.

table 2 issuance times

Table showing when both graphic and text products will be updated. Helpful if the weather is bad and you are waiting for the next forecast!

Other graphic products, such as the Surface Map and IFR/MVFR Chart won’t change, however the issuance and update times will.  The AAWU has provided a table (above) summarizing the timing of both text and graphic product which provide a roadmap to the new scheme.

These are significant enhancements to the products available to Alaskan pilots, and a downloadable document summarizing them is available online that contains examples and a more complete description of the schedules and changes.  If you have feedback on products, the National Weather Service would like to hear it. An easy way to reach them is to shoot an email to mailto:[email protected].

As pilots we need to remember that the accuracy of these products is influenced by the PIREPs we file, either confirming forecast conditions, or alerting forecasters when conditions are changing faster than expected. Please take time to file an extra PIREP or two as you fly.

So a modification to an old adage might be… “If you don’t like the weather you see at the moment, just wait for the new forecast.”  Thanks to these changes, the new forecasts will be showing up more graphically and more frequently than before.