Introducing our WeatherSpork member referral program

Are you a fan of WeatherSpork?  If so, we have a way for you to earn our gratitude!  With each new member you refer, we will extend your annual member by one month.  Twelve referrals means you’ll get an entire year free.  It’s that simple.  You could become a Sporkie for life if you referred at least one new member each and every month.  So what are you waiting for…let’s get Sporking!

To receive credit be sure that when your friend joins by visiting WeatherSpork.com they include your first and last name in the “How did you hear about WeatherSpork and/or AvWxWorkshops.com?” field during the registration process.  Then within the next 5-7 business days (or less) you will see your expiration date pushed into the future by a month.  If you’ve already referred a friend or two since we released the app on March 1, then your membership has already been adjusted.  Thanks for your contribution!

We know that WeatherSpork can’t grow unless our customers stand behind the product.  We hope that you can help us grow to remain the gold standard for aviation weather in the coming months and years.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Spork meets Droid, Android, that is!

We are excited to let you know that we’ve just released our new app to Google Play for those that use an Android device.  With very few exceptions, the WeatherSpork app will have the same look and feel and has all the same features as our popular iOS and web-based versions of WeatherSpork.  So when you are an “exSporkt” on one device, you are an exSporkt on all WeatherSpork platforms.  U.S. Droid users, don’t delay, go right now and visit Google Play. You won’t be disappointed.

At this time, WeatherSpork is only available to U.S. customers for Google Play.

 

 

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Crosswind & prevailing wind color depiction on Meteogram view

There’s no doubt that wind is the leading cause of weather-related aircraft accidents.  Even so, strong crosswinds can make for a challenging landing even for the most seasoned pilot. So to help alert you to nasty wind conditions expected at an airport over the next three days, WeatherSpork version 4.3.5 has enhanced the wind Meteogram by adding “traffic light” colors (red, yellow and green) to the time-series wind graph depicted on the Meteogram view.

For an airport, the observed or expected prevailing wind (shown above) is plotted as a continuous line and color coded by wind speed using the following colors:

  • Green – 0 to 10 knots.
  • Yellow – 11 to 20 knots.
  • Red – greater than 21 knots.

The crosswind component is depicted as a color-filled graph overlaid on the same time-series depiction. Crosswinds are evaluated by determining the best opportunity runway based on the observed or forecast winds at the surface using the following colors:

  • Green – 0 to 10 knots.
  • Yellow – 11 to 15 knots.
  • Red – greater than 16 knots.

So the next time you go flying be sure to check the WeatherSpork Meteogram to determine if a challenging takeoff or landing are in your future.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

 

New weather imagery for you jet jockeys

If you are flying in the flight levels this summer and especially the upper flight levels, we have some new static weather Imagery for you!  We recently added to WeatherSpork version 4.3.4 new guidance that is going to be very popular with you jet jockeys out there.   It’s from the High Resolution Ensemble Forecast (HREF) which is updated four times a day and provides two probabilistic forecasts for echo top heights at hourly intervals with a lead time of 36 hours.

Two probabilistic forecasts are available in WeatherSpork.  You will find this in the Imagery view under the HREF Model.  Choices include echo top heights greater than 30,000 feet MSL and echo top heights greater than 35,000 feet MSL.  The height of the echo top is a forecast for the highest simulated radar echo top (top of the precipitation core) with an expected reflectivity not less than 18 dBZ.  Remember, these are forecasts, not actual NEXRAD echo tops.  And note, the cloud tops are often higher.

Notice the scale at the bottom of the chart.  The echo top height forecast depicted on the chart is a calibrated probability.  The highest probabilities are on the right side of the scale (red and purple) with lowest probabilities on the left (green and blue).  So a forecast that’s depicted in red means there’s a 90 to 100% chance at the forecast valid time, there will be tops greater than 30,000 feet (or 35,000 feet depending on the forecast you are using).   Therefore, flying through or near areas of red and purple will likely require flying at an altitude higher than 30,000 feet (or 35,000 ft).  They may be areas you want to avoid.

A flight at 30,000 feet (or 35,000 feet) through areas without colors depicted will very likely be above the highest echo tops or in an area without precipitation forecast.

The valid time is posted at the top of the chart as shown above (underlined in red).  It uses a YYYYMMDD HHMMZ format. For example, the chart abvove is a 33 hour forecast valid at May 9, 2018 at 03Z (20180509 0300Z).  The time on the left side is the initialization time of the model or what is referred to as the “run time” or “cycle time” of the HREF forecast model.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

April 2018 SporkNews

If you are new to WeatherSpork, we want to say welcome to the Spork family!  Each month we plan to send out this e-Newsletter we call SporkNews to keep you updated on the latest developments in WeatherSpork.  If you use social media, feel free to follow us on Twitter (@weathersporkapp), Facebook (http://facebook.com/weatherspork) and on our YouTube channel (https://www.youtube.com/channel/UCxHi72FoCshPjHC2vIFXCkg).  Of course, don’t forget to check out Scott’s blog, The Spork Report to learn more about weather and the app.

New features of WeatherSpork

In April 2018, we raised the roof on the Route Profile view.  WeatherSpork version 4.3.0 changed the maximum altitude displayed from FL200 to FL450.  The Meteogram view remains limited to FL200.  We also made a couple of other enhancements in version 4.3.0 you may be interested to learn.

For those pilots that exclusively use an Android device, in May we will be adding WeatherSpork to Google Play.  For now, WeatherSpork is designed to be responsive and will work nearly identical to the app on portable devices using a browser.  For the best experience we recommend Google Chrome.  To use the browser version of WeatherSpork, simply open a browser and visit http://weatherspork.com.  You’ll find a menu selection near the top of this page to login.

Missing airports

Since the app was released in March, we have gotten a fair number of questions about missing airports in WeatherSpork.  When initially designed, the app was predicated on having an aviation forecast (ceiling, visibility, wind, etc.) available at every airport.  Our signature feature, the Wheels Up Departure Advisor, needs to have these forecasts to evaluate the expected weather along the route of flight.  This meant that airports that did not have a MOS forecast were not included.  However, we are in the process of expanding this database to include most airports in the U.S. that have a surface observation (METAR).  For now, we suggest that you use the closest airport.  In most cases, the Route Profile, Map and Grid views will not be significantly different.  Airports outside of the U.S. will be added in the future.

Live workshops for 2018

If you’ve never attended the Weather Essentials for Pilots live workshop, it’s a great opportunity to dedicate a weekend to learn how to minimize your exposure to adverse weather.  It will challenge your most basic understanding of the weather. Four live workshops have been scheduled this year in the cities of Portland, Oregon (May 5-6), Milwaukee, Wisconsin (May 19-20), Williamsport, Pennsylvania (Sept 8-9) and Houston, Texas (Sept 22-23).  There are just a few seats remaining for Portland (registration cutoff is today at 5 pm EDT), but plenty available for the remaining workshops.  Elite members get a 15% discount on the price of tuition for this class. Details can be found here.  Come and learn more about weather.

Register now >>>

Speaking schedule for 2018

Scott will be speaking at the four AOPA fly-in events, AirVenture and the annual Cirrus Owners and Pilots Association Migration.  If you are planning to attend any of these events, please stop by and say hello!

  • AOPA fly-in, Missoula, Montana, June 16 at 9:00 a.m.
  • AirVenture in Oshkosh, Wisconsin (date and time TBD)
  • AOPA fly-in, Santa Fe, New Mexico, September 15 (time TBD)
  • AOPA fly-in, Carbondale, Illinois, October 6 (time TBD)
  • COPA Migration, Las Vegas, Nevada, October 13 (time TBD)
  • AOPA fly-in, Gulf Shores, Alabama, October 27 (time TBD)

New videos

Periodically throughout each month we will be creating educational videos like this one that explains what Model Output Statistics (MOS) is all about.  You also may have enjoyed our three part video series on thunderstorm planning with WeatherSpork.  Lastly, in this video we show you a little shortcut from the Route Profile view to the Airports view.

That’s it for the April edition of SporkNews.  As always, we need your help. Please take a few minutes today and spread the word to other pilots about this amazing new app that will get better with age and your support.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

 

Just raised the roof on WeatherSpork!

With WeatherSpork version 4.3.0, you now have the option of selecting FL450 as the upper limit on the clouds and weather display.  The upper limit on earlier releases was restricted FL200.  This will allow you to see winds (speed and direction) as well as clouds and advisories (G-AIRMETs and SIGMETs) that extend higher in the flight levels or FL450.

To change the altitude limit, go to the Route Profile view and simply tap or click on the black route button at the top.  That will bring up the Route Profile settings.  Scroll down in the settings window (shown below) to find the Maximum Altitude setting and select FL450 and tap or click Save. The other selections of 6,000 ft MSL, 12,000 ft MSL and FL200 will remain available.

This enhancement only affects the Route Profile view.  The Meteogram view will still remain limited to a maximum altitude of FL200.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

New static Imagery from the HREF model

With WeatherSpork version 4.3.0, we’ve extended the static Imagery to include aviation forecasts from the High Resolution Ensemble Forecast (HREF) model.  The HREF is updated four times a day and provides a forecast lead time of 36 hours at one hour time increments.  In WeatherSpork you can find these in the Imagery view right below Graphical MOS under HREF Model as shown below.

These six choices provide the probability of a flight category of Marginal VFR (MVFR), IFR and Low IFR (LIFR) as well as the probability of a ceiling below 3,000 ft, 2,000 ft and 1,000 ft AGL.  In the sample below, the colors represent probabilities shown on the scale at the bottom of the chart.  Colors such as red and purple are indicative of ceilings that are forecast to be less than 3,000 feet as they are in northern Ohio; of course, they could be much less than 3,000 feet in this area.  Keep in mind that non-filled areas do not mean clear skies per se.  This simply means that there is a very low chance the ceiling will be less than 3,000 feet in these areas. This 21 hr forecast is valid at 1500Z on April 28, 2018.

The probabilistic ceiling forecasts above are additive in nature.  In other words if there’s a high probability of a ceiling less than 1,000 feet, there’s also a high probability of a ceiling less than 2,000 feet and 1,000 feet respectively.

Flight category combines both the ceiling and visibility as shown in the table below. These flight categories are sometimes improperly referred to as flight rules in many flight planning apps.

In addition to the probabilistic forecasts for ceiling, the HREF also provides a probabilistic forecast for specific flight categories that include LIFR, IFR and MVFR.  The example below has a forecast lead time of 22 hours and is valid at 1600Z on April 28, 2018.  Similar to the probabilistic ceiling forecasts above, higher probabilities of a MVFR flight category are shown in red and purple colors like you see in Indiana and Ohio in the example below.  Non-filled areas simply mean that the chances of a MVFR flight category are very low.  Unlike the probabilistic ceiling forecasts above, these forecasts are not additive.  That is, in an area where there’s a high probability of a MVFR ceiling, there may be a very low probability of a LIFR ceiling.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

An introduction to Model Output Statistics or MOS

A majority of certificated pilots have never heard of Model Output Statistics or what is referred to as MOS (pronounced moss).  MOS isn’t new and has been around since the 1960s, but is just starting to be leveraged by many pilots.  Back in 2016 the FAA added a brief description of MOS to the Aviation Weather Services advisory circular AC 00-45H Change 1 so it is now officially recognized by the FAA as supplemental guidance for preflight planning. WeatherSpork makes heavy use of this automated guidance which drives the signature feature in WeatherSpork called the Wheels Up Departure Advisor (WUDA) found in the Map, Grid and Route Profile views.  MOS is also used by meteorologists as one of several tools to issue terminal aerodrome forecasts (TAFs).

This video below was an audio and screen recording of a presentation given by Scott Dennstaedt to a local flight school in Charlotte.  Watch this video to learn a bit more about MOS and its advantages as flight planning guidance.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Dangers of airframe icing in stratocumulus clouds

Normally pilots look forward to improving weather conditions after the passage of a cold front. The cold, dense air behind the front becomes negatively buoyant and sinks which tends to dry out the air. Moderate northwesterly winds will often prevail on the cold side of the front making for moderate mechanical turbulence sometimes extending up to 8,000 feet AGL. Other than some turbulent air, we don’t typically encounter much in the way of adverse weather behind such a cold front with few clouds, no precipitation and unlimited visibility.

During the spring, how many pilots think about the airframe icing threat that can occur in an overcast stratocumulus deck after the passage of cold front? Even a thin stratocumulus cloud deck like the one shown above can contain a liquid water contents approaching 0.5 g/m3 – especially near the tops. When the temperature is just right, these harmless-looking clouds can surprise a pilot with some moderate or even severe icing while climbing or descending through them.  This is especially concerning to those pilots flying aircraft without certified ice protection systems (IPSs).

Stratocumulus decks have very distinct characteristics from other clouds. Although not completely smooth on top like a stratus deck, they have rather even tops with a quilted-like or lumpy appearance when viewed from above. While a stratocumulus deck can be broken or even scattered it is quite common for these cloud decks to be overcast when they occur after the passage of a cold front. They are rooted in the boundary layer near the surface similar to other cumuliform clouds, but an overcast stratocumulus deck can extend for hundreds of miles making them difficult to avoid.

Let’s examine a case in the middle of April near Atlanta, Georgia where many pilots were reporting moderate icing in one of these stratocumulus decks.

This story starts out in the prior day.  A strong cold front moved through the Atlanta area during the late morning, bringing with it severe thunderstorms with tornadoes and microbursts in the afternoon from northern Virginia down to the peninsula of Florida as shown above. Temperatures ahead of the front climbed into the low 80s.  As the cold front (shown below) moved off the southeastern Atlantic coast the following day, this set the stage for a cold northwesterly wind to push a cold air mass over a fairly warm and wet ground in the Atlanta metro area.  A warm and moist surface with cold air moving in aloft is the perfect recipe for the genesis of a juicy stratocumlus cloud deck.

Skies were generally overcast all morning throughout the Atlanta area as can be seen by the surface observations below.  Ceilings were marginal VFR ranging from 2,100 feet to 2,600 feet.  In an overcast cloud deck, there’s no real way to know its depth from looking at the clouds from below.  Depending on the sun angle, a darker cloud base is indicative of more condensate, but this was early in the morning where the bases will generally be darker.  But in the Atlanta region, this was definitely an overcast stratocumulus deck like the one shown in the picture below.

KPDK 161453Z 30013G21KT 10SM OVC021 04/M01 A3000 RMK AO2 SLP167 T00391011 53014
KPDK 161353Z 27011G18KT 10SM OVC021 03/M01 A2998 RMK AO2 SLP160 T00331011
KPDK 161253Z 26013KT 10SM OVC022 03/M01 A2996 RMK AO2 SLP156 T00331011
KPDK 161153Z 28011KT 10SM BKN021 OVC028 04/M01 A2995 RMK AO2 SLP151 60000 70060 T00391006
KPDK 161139Z 26010KT 10SM BKN026 OVC033 04/M01 A2996 RMK AO2 T00391006

Temperatures at the surface during the morning were a chilly +3°C to +4°C.  But one characteristic of stratocumulus clouds is that there is very unstable air below.  This means the temperature decreases at the dry adiabatic lapse rate of 3°C for every 1,000 feet gain in altitude.  Except for right at the surface, this lapse rate is the most unstable that unsaturated air can be.  This is best seen on a thermodynamic chart called a Skew-T log (p) diagram.  The Skew-T analysis below for Dekalb-Peachtree Airport (KPDK) captured through the WeatherSpork Airports view demonstrates a textbook stratocumulus signature.

As can be seen above, the stratocumulus clouds extend from the bases at 2,500 feet MSL where the temperature and dewpoint converge with saturated conditions to the tops at roughly 5,500 feet MSL or where the temperature and dewpoint diverge.  That’s a depth of roughly 3,000 feet at 14Z (they likely varied in depth over the region).  Notice the large lapse rate below the cloud bases with nearly moist absolute instability within the actual cloud deck itself.  This is the most unstable lapse rate that can occur in saturated air. Remember that this area had received a fair amount of rain, so there was plenty of fuel being pulled into these clouds from below.

The tops are capped by a very strong temperature inversion which limits vertical cloud growth which is the classic signature to stratocumulus clouds.  So you can think of this “system” as a lid on a pot of boiling water.  The unstable air ascends, expands and cools to produce these clouds and given that the clouds are also unstable inside, the momentum in the capped updrafts gives those clouds the lumpy appearance when viewed from above.  In fact, taking a closer look at this sounding analysis shown below with a parcel lapse rate added, there is a fair amount of convective available potential energy (CAPE) that allows for efficient transfer of water vapor into condensate (liquid drops).  It’s like squeezing the water out of a sponge.

While not specifically shown on the Skew-T diagram, the graph below is a trace of the liquid water content of an instrumented research aircraft that climbed through one of these cloud decks.  The liquid water content is shown increasing to the right on the X-axis.  Height is shown on the Y-axis.  Because these clouds are rooted in the boundary layer, the have a median volumetric diameter drop size of less than 50 microns (small-drop icing scenario).  A liquid water content value at the top of this cloud deck shown in the graph below of 0.5 g/m3 is huge.  The liquid water content can be significant enough to overwhelm many aircraft when flying in the tops of these clouds.

Temperature is also important.  The cloud top will typically exhibit the coldest temperatures in these clouds.  In this case for Atlanta, the cloud top temperature is in the perfect range at -7°C if you want to see icing conditions.  That guarantees an all-liquid process making for a juicy cloud containing no ice crystals.  You can also see the cloud top temperature in the color-enhanced infrared satellite image below.  Colors in the image are based on temperature in degrees Celsius.  When clouds are present, this is the temperature of the cloud top, otherwise it’s the temperature of the surface of the earth. The stratocumulus deck shows up nicely over northern Georgia as a yellow color implying a cloud top temperatures of -8°C which matches what is shown in the Skew-T diagram.

Some of this cloud cover in extreme northwest Georgia was covered under an icing G-AIRMET valid at 15Z for widespread moderate icing from the surface to 10,000 feet MSL (shown below).

Lastly, there were a number of pilot weather reports for icing in and around the Atlanta region that included an urgent pilot report from a Boeing 737 at 5,000 feet MSL south of Atlanta.  The moderate ice reports during the morning tended to be around the tops of this cloud deck.

ATL UUA /OV ATL085020/TM 1245/FL050/TP B737/TA -3/IC MODERATE RIME

If you are not a member of WeatherSpork, your best online source for aviation weather and education, please consider becoming part of the WeatherSpork family.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Thunderstorm planning with WeatherSpork, Part 2

Part 1 of this series of three videos focused on how to use WeatherSpork to find the best time of departure for a trip the following day given a threat of thunderstorms along the proposed route.  Part 2 of this series takes place on the morning of this flight.  Watch this 20 minute video below to see if yesterday’s guidance was still on track.

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

Scott Dennstaedt
Weather Systems Engineer
Co-founder, WeatherSpork

Scroll to top