March 2018 SporkNews

Hello and welcome to WeatherSpork!

March 1, 2018 was the public debut of WeatherSpork, your best online source for aviation weather and education.  At WeatherSpork, we couldn’t be more pleased at the response we’ve gotten thus far.  Over the last month we’ve received a ton of very positive feedback you can read here. A big thanks to our current members and to all of those that have taken the leap of faith and joined the WeatherSpork family.  We appreciate how many of you have already spread the word to other pilots about this awesome new app. Please keep that momentum going!

What’s new

This month we spent refining the app, making it more stable and fixing a few bugs.  You will find a history of the content of each of our releases on our website here.  At WeatherSpork, we are working hard to add new functionality to the app.  While we don’t have specific dates,  we have dozens of groundbreaking features we are planning to add over the next year – you can read about a few of those here in Scott’s blog, The Spork Report.

From time to time we will be adding new weather imagery to the WeatherSpork app. In this month we add the National Forecast Chart.  It will describe the big picture of the weather over the next three days.  Read more about that new imagery in The Spork Report here.

Webinars

In March we held two free live webinars.  If you were not able to attend, you can enjoy the recorded version of the second webinar here.  We will likely hold one or two free webinars each month as we introduce new functionality and provide some tips on how to use the app in the context of your preflight weather planning.  If you want to be notified when these webinars are occurring, be sure that you have your email preferences set appropriately by logging into avwxworkshops.com and review your settings under the My Account page.

Running WeatherSpork on portable devices

We have been beta testing the WeatherSpork app on Android devices and feedback thus far has been excellent. For the moment, if you don’t have an iPad or iPhone, no problem.  WeatherSpork is designed to work on any of your portable devices using an Internet browser.  In fact, it’ll look and operate just like the app.  To have the best experience, however, we recommend using Google Chrome to launch the web-based version of WeatherSpork.

Come visit us at Sun ‘n Fun this year 

If you are headed to Lakeland, Florida this year for Sun ‘n Fun, be sure to mark your calendars for an Introduction to WeatherSpork. This will be a live presentation to be held Tuesday, April 10, 2018, starting at 13:00 EDT in Room CFAA-9.   The program offers one credit for Basic Knowledge towards the Wings program.   For more information or to reserve your seat you can visit the FAASTeam.gov website here.  Looking forward to meeting you there!

Stay tuned for more SporkNews next month.  Fasten your seat belts, we are “all” in to make your weather planning much simpler so you can fly with more confidence.

“Most pilots are weatherwise, but some are otherwise.”

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Weather weirdness explained

As you might imagine, I get a lot of questions from pilots about weirdness in the weather. They see something that doesn’t look quite right or doesn’t make logical sense and want to know more.  With a little forensic weather sleuthing, I can usually explain what’s going on.  Here’s one such request for more information…

One of my WeatherSpork customers saw the following two METARs from Albany, New York and Glens Falls, New York; the two airports are just 37 nm apart.  However, the winds were significantly different.  Given their close proximity he was curious why such a large difference in wind speed?

KALB 300151Z 17013G25KT 3SM BR OVC006 09/08 A2981 RMK AO2 SFC VIS 4 SLP097 T00940078=
KGFL 300212Z AUTO 29003KT 3/4SM -RA BR SCT003 OVC011 06/06 A2980 RMK AO2 RAB12 P0000 T00610061=

Some of the reasons for this are related to terrain.  But I’m not going to focus on that element.  Instead, let’s drill down at each location and see what’s going on.  But first, you might think there’s a front in between these two airports.  Not the case as you can see from this surface analysis chart valid at 00Z. The red circle shows the locations of both KALB and KGFL.  Certainly no front in the immediate vicinity of either airport.

First and foremost, to see significant differences in weather between two airports in close proximity isn’t all that uncommon.  In some places around the country it’s quite predictable.  Pilots that frequently fly out of these airports can usually describe these local anomalies.  But the devil is in the details.  And yes, that means we cut to the Skew-T diagram to see those details.

Gusty winds are usually a result of air “mixing down” from faster air above.  An unstable atmosphere near the surface (in the planetary boundary layer) is a good example of when the atmosphere is mixy (yes, not a real word, but what seemed appropriate here).  This is quite easy to see in a thermodynamic diagram called a Skew-T log (p).  Below is the Skew-T analysis** from Albany valid at 02Z (highly zoomed in).

Notice how the temperature (shown in red) is nearly dry adiabatic (lapse rate of 3 degrees C/1000 ft). That’s an unstable situation.  Unstable air can easily move up and down.  If you look at the same Skew-T analysis below, notice the wind at the top of the boundary layer (about 1300 ft MSL in this case) is moving along at 31 knots.  The unstable air allows the winds at the top of the boundary layer to “mix down” toward the surface creating gusts.  Using the wind at the top of the boundary layer is a great way to estimate the wind gusts at the surface when there’s no TAF available.

What about Glens Falls?  In the Skew-T analysis below also valid at 02Z, you can see the atmosphere is very stable.  This essentially decouples the surface from the winds aloft.  In this stable environment the stronger winds aloft can’t mix down to create surface gusts.

The moral of the story is that we should be very careful assuming that two airports in close proximity will have the same weather.  So using the “closest” TAF  isn’t always a good idea.  As you can see from this example, the winds can be significantly different.

** An analysis is NOT a forecast and is always valid in the past despite what you might see on some flight planning apps.

“Most pilots are weatherwise, but some are otherwise.”

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

National Forecast Chart now part of the WeatherSpork imagery

In WeatherSpork version 4.2.9 we recently added new forecast guidance to the Imagery view.  The new National Forecast Chart is  issued by the Weather Prediction Center (WPC) and provides an overview of expected weather for up to the next three days, with emphasis on certain hazardous and significant weather. This guidance summarizes forecasts from the Storm Prediction Center (for severe thunderstorm and tornado outlooks), the National Hurricane Center (for tropical storm and hurricane forecasts), and the Weather Prediction Center (for information concerning heavy rainfall, flooding, winter weather, and general weather). With overlaid frontal forecasts, these displays serve as a good overview of the expected weather for the next three days.  Below is the 2200Z issuance of the Day 1 National Forecast Chart.

The Day 1 (today’s) National Forecast Chart is prepared twice daily at the WPC. The initial product is issued by 5 a.m. EST/EDT, with an update provided by 2200 UTC (5 p.m. EST).  The Day 2 (tomorrow) and Day 3 (day after tomorrow) National Forecasts are prepared once daily and issued by 5 a.m. EST/EDT. Valid times of the features displayed in these products vary depending upon issuance time and the particular weather phenomenon of interest. In WeatherSpork, you can find the new National Forecast Chart imagery conveniently between the MSL Surface Analysis and Prog Charts as shown below.

 

“Most pilots are weatherwise, but some are otherwise.”

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Release notes for v4.2.8

  • Fixed a bug where SIGMETs were not being filtered correctly in Route Profile and Meteogram views.
  • Fixed a bug where incorrect destination airport sometimes appeared in Route Profile, Meteogram, and Map views.
  • Additional minor bug fixes and usability improvements.

About “time” in WeatherSpork

It’s essential to know the valid time of any weather guidance you may use.  There are two choices in WeatherSpork for time, namely, device time (local time) and Zulu (GMT).  In WeatherSpork you will find times listed in many locations.  With the exception of the charts shown in the static Imagery, you have the option of displaying local or Zulu time.  You can make that choice in your Preferences view as shown below.

If you set your preference to Zulu (as shown above), you will notice a Z located behind each time in the route profile as shown below.  If there isn’t a Z, then you have your preferences set to the device time (local).

As mentioned above, the only exception is the static Imagery.  The time is typically Zulu (UTC) and that will be labeled in some location on each image.

 

“Most pilots are weatherwise, but some are otherwise.”

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Scroll to top