Top mistakes pilots make in a convective environment

     Deep, moist convection, better known as thunderstorms are the nemesis of all aircraft, big or small. Avoidance is mandatory.  However, pilots continue to find themselves tangled up in these giants and very few live to tell about it.  What mistakes are these pilots making that put them at risk?  Here are a few points that come to mind.   

     There's no question that weather impacts our flying activity more than any other single physical factor.  Ironically, many pilots will freely admit that weather is their weakest link - even seasoned pilots.  A majority of newly certificated pilots possess a dearth of practical skills necesssary to minimize their exposure to adverse weather.  Moreover, they fail to advance their weather knowledge beyond what little they were required to learn during their private and/or instrument training.  

     Most low-time pilots believe that as they accumulate flying experience, it will somehow just fall into place and someday they will magically acquire the weather knowledge they were always missing.   To the contrary, according to a recent study, the NTSB states, "It appears that pilots generally require formal training to obtain weather knowledge and cannot be expected to acquire it on their own as they simply gain more flight experience."  

     The blame shouldn't rest entirely on the pilot.  Much of what a pilot has heard or read about thunderstorms is probably worthless.  A good deal of what a pilot is taught is laced with misconceptions and outright nonsense.  Terms like "pop-up" or "air mass" thunderstorms are a perfect example of bad information.  Thunderstorms develop at a particular time and place for a reason, even though it is often difficult to the point of being impossible to diagnose those reasons. 

     There are just not enough resources available to the average pilot that can take them beyond the basics short of a formal curriculum in meteorology.   Pilots are not aware of or just don't know how to use the dozens of weather products freely available on the Internet because there are no formal educational resources explaining how to use them in the context of their flight.  This is one of the reasons I designed and built AvWxWorkshops.com as an outlet for pilots to seek that much needed training.  

     Whether you are taking a very short trip or one that may last several hours, knowing how to "read" the environment before you depart is paramount.  Pilots are always taught that flying in the morning is the best option.  This is generally true, but on any given day, it's possible for there to be ongoing convection in the morning associated with a severe mesoscale convective system (MCS).  Even when the radar image is quiet in the morning, if your flight takes you into the afternoon hours, you'll definitely want to paint a mental picture of what that environment might look like.   

     Many pilots fail to take the time to accurately describe the convective environment they may face before they depart.  It requires a great deal more than just knowing there are thunderstorms in the immediate forecast somewhere along your route.  Characterizing the convection and developing a sense of what is forecast to occur will help you stay two steps ahead of it.  Will it be mostly a scattered or isolated pulse-type area of thunderstorms?  If so, will this area likely reach convective SIGMET criteria such as shown below?  Is the environment conducive for microbursts?  Will the MCS that developed overnight persist through the morning or will it dissipate before you depart?  Will a solid line of convection form ahead of the cold front?  When and where will the onset of that pre-frontal convection be located?  What will be the direction and speed of movement be once these storms develop?  Will they be severe?   

     Wouldn't it be great if you were able to set the NEXRAD loop in motion and have it continue to run beyond the current time playing out what might happen in the next six hours?  That would certainly eliminate much of the guesswork.  There's no doubt that all pilots would love to take a peek at the future NEXRAD image.  The simulated reflectivity product shown above is an example of a product that is the next best thing to the NEXRAD crystal ball. Simulated reflectivity is an hour-by-hour model-based forecast that will help you to visualize all aspects of the convective environment including thunderstorm onset and dissipation, speed and direction of movement, organizational profile and intensity just to name a few.  Since it is a model-based forecast, it is subject to serious errors.  Be sure to use this in concert with other official NWS weather forecasts.            

Fly upwind of convection 

     Once confronted with a thunderstorm, some pilots make the wrong tactical decisions.  Of course, most understand that staying out of the visible cloud boundary is the first rule in thunderstorm avoidance.  Staying out of the visible cloud, you will likely keep you clear of the truly ugly parts of the thunderstorm. However, it is widely known that severe or extreme turbulence, hail, lightning and strong straight-line winds can exist outside of the visible thunderstorm boundary.  Most of the time, these elements occur downwind of the thunderstorm, in other words, in its direction of movement.

     Flying upwind of the cell helps in several ways.  First, it keeps you on the side of the tiger that has no teeth.  While there can be an occasional outflow boundary down low on the upwind side, most of the time the air is glassy smooth.  Second, it is moving away from your position or route.  So any latency you might see in your satellite-based weather is magnified because what you see on your display has likely already moved away from that point.  By the time you get to this point five minutes later, the cell has moved off keeping you safely out of harm's way.  Flying on the downwind side of convection provides just the opposite effect with latency making it difficult to judge where the convection might be in five minutes.  

Choose your help wisely

     When down low, stay away from any visible rain shafts (as shown to the right) and stay out of the rain curtain for larger storms.  If you have no onboard radar or satellite-based weather in the cockpit enlist help from ATC.  Be very careful here; pilots often take direction from ATC that's not in their best interest.  Controllers don't see what you see.  Approach control weather radar is typically fairly accurate, but they can't see a building cell about to unleash its fury in the next five minutes.  Also, they are primarily concerned about how your deviation will fit in with their current traffic flow and less concerned with taking you on the upwind versus downwind side of a thunderstorm.  Be assertive and refuse any clearance or instruction that takes you into an area that doesn't keep you in visual meteorological conditions.

     The enroute flight advisory service (EFAS), better known as flight watch is another outlet for pilots flying in a challenging convective environment without any onboard weather.  Flight watch can be reached on 122.0 MHz and should be used as a strategic tool 50 or more miles from reaching the nearest convective activity.  It's not what you can see outside of your windscreen that's the most critical; it's the convection you can't see that might be lurking behind it.  General guidance is typically useless.  Be sure they offer a route from your present position with specific waypoints or navaids that will minimize your exposure.      

     If you can't reach flight watch on 122.0 MHz, try the high altitude flight watch frequencies.  High altitude flight watch is designed to service pilots flying at FL180 or higher.  However, they would be happy to help you even if you are flying around the building cumulus at a much lower altitude.  Each air route traffic control center (ARTCC) has such a frequency.  You can find these frequencies listed in the inside-back cover of the airport facilities directory (A/FD).  

     There are times where you just can't get there from here.  When a pilot runs out of choices and the weather is closing in, pilots often make the mistake of pressing on.  They are optimistic that it's not as bad as it looks.  After all, three other aircraft before them, made it in just fine.  Dealing with a challenging convective situation adds to your workload.  Within seconds you can quickly get behind the airplane, missing items on the checklist, cutting corners and making mistakes in haste.  Landing short of your destination is perhaps the easiest solution.  Don't pass up a perfectly good airport to make it 20 miles closer.  Land and wait it out.    

     Gust fronts don't show up on satellite-based weather products and often precede the line of convection by 5 or more miles. Pay special attention to radar signatures such as a bow echo.  Bow echoes almost always contain strong straight-line winds with peak winds of 50 knots or greater at times.  Winds can shift 180 degrees within a few minutes even when the actual rainshaft is five or more miles away forcing a tricky go-around.  As you approach your destination, listen to the weather for airports upwind from your destination in the path of the storm.  They will often heed the warning to land and wait it out.                

     A convective environment is one that demands a little extra cushion.  If possible, come around the backside of the weather keeping in mind that most lines of storms move to the east or southeast while the individual cells normally move northeast.  If you had characterized the convection before you departed, you should know the expected movement of the weather.     

     Finally, pilots tend to also forget how much a deviation around the weather can eat into your fuel reserves. Pilots tend to make the mistake of not allowing for the extra time in the air.   In a convective environment, add 30 minutes to your normal reserve.  Once you reach this point and have not landed at your destination or fuel stop, call it quits.  Land and refuel and re-check the weather.  You never know what might be lurking near your destination.  

     It is inevitable; when you buy any product that has a dozen or more features, you only use a few of them on a consistent basis.  Why pay for all those "extras" you don't really need?  You might be in that same situation with your XM-based satellite weather subscription.  Let's take a deep breath and evaluate what each package offers in terms of capability...you might be surprised that you can really do without all of those extras. 

     XM-based satellite weather currently offers three levels of subscription.  Of course, each package adds more features, but essentially doubles the cost with each upgrade. When WxWorx offered this product for the first time, there was one and only one choice.  The Aviator package hasn't changed a lot in features and price since it was first introduced.  At $49.95 per month, it offered nearly a dozen different weather products and forever changed a pilot's situational awareness of the weather for all phases of their flight.    

     A couple of years later, WxWorx began to offer the Aviator LT, a lite version of the Aviator package.  For $29.99 per month, Aviation LT stripped off nearly two-thirds of the features leaving the NEXRAD mosaic, METARs, TAFs, precipitation type and TFRs.  Because it is so expensive, they opted not to include ground-based lightning in the Aviator LT subscription.  

     Just last year at AirVenture 2008, WxWorx introduced their premium package called Aviator Pro.  The monthly subscription price is double that of the Aviator package at $99.99.  Of course Aviator Pro encompasses all of the features of its predecessor, but also adds two icing products, high-level turbulence, convective outlooks and mesoscale discussions from the Storm Prediction Center (SPC) and hurricane tracks from the Tropical Prediction Center (TPC).  At the same time, they expanded the Aviator package by adding severe thunderstorm and tornado watches and pilot reports.     

 The Variables     

     What package you choose ultimately depends on your mission.  If you fly mostly in Florida bouncing around at 5,500 feet in a Cessna 172, you probably don't want to spring for the Aviator Pro package; the Aviator LT may be all you need.  If you do a substantial amount of flying in Canada, you may want the Aviator package since it includes the Canadian radar data.  Or if you fly at or above FL210 on a frequent basis, you may want to subscribe to the Aviator Pro package. 

     If you don't fly very often or fly very far, the Aviator LT might just be your best choice.  Pilots who fly more frequently or fly greater distances will be exposed to more challenging weather more often.  In this case, some of those extras might make a difference. 

     This will also depend on the capabilities of your XM satellite-based weather receiver.  Not all vendors support every product that is broadcast and arrives at your receiver.  Even if you wanted to upgrade to the Aviator Pro, you may find your Avidyne panel-mounted multi-function display (MFD) doesn't support many of the features contained in the Aviator or Aviator Pro package.        

Forget Aviator Pro

     Let's get the easy one out of the way first.  Aviator Pro is their premium service.  This includes the Current Icing Product (CIP) icing analysis, Supercooled Large Drop (SLD) icing analysis (shown above), Graphical Turbulence Guidance (GTG) forecast, SPC Day 1 convective outlook, SPC mesoscale discussion, visibility and the hurricane track product.  There's absolutely nothing here that adds a significant amount of additional situational awareness for most pilots during any phase of their flight.    

     The CIP and SLD products are those that are available on the Aviation Digital Data Service (ADDS).  At best, the CIP and SLD icing analysis products are 15 to 20 minutes old when they are broadcast.  Then you get to stare at these images for an additional hour before they are once again refreshed with the next hour's analysis.  So it is truly a glimpse of the recent past.  Moreover, the icing analysis is displayed in 3,000-foot increments even though the native resolution of the product is 1,000 feet.  A lot can happen from an icing perspective within 3,000 feet, especially SLD.  Unless you fly an aircraft with a certified ice protection system (IPS), it is not advisable to use it for real-time avoidance of icing conditions.    

     The turbulence product that is broadcast is generated from the Graphical Turbulence Guidance (GTG) product and is the same product as available on ADDS.  Unlike CIP, it is only available at altitudes at or above FL210 (despite what it says in the WxWorx documentation which fails to point out this little detail).  It is also only broadcast in 3,000 foot increments through FL420.  Keep in mind that GTG isn't an analysis of the current turbulence conditions; this product is a two hour forecast based on the Rapid Update Cycle (RUC) for clear air turbulence (CAT) only.  It is valid at the top of the hour.  Turbulence, especially clear air turbulence is often found in very narrow layers in the atmosphere.  It is highly possible that a severe clear air turbulence event could be contained between FL210 and FL240.  Unless you fly a turbocharged or pressurized aircraft, this product will not be useful.

     The Storm Prediction Center (SPC) Day 1 convective outlook gets updated four times throughout the day and will hardly substitute for your NEXRAD image which is on the order of five to eight minutes old.  This outlook represents more of a planning tool before you depart and doesn't add any significant awareness en route.  

     Similarly, the SPC mesoscale discussion is a product (example shown left) that is very useful before departure.  Mesoscale discussions are normally issued for regions that are conducive for severe weather, heavy rain or significant winter weather such as freezing rain or heavy snow.  Often mesoscale discussions are a precursor for a severe thunderstorm or tornado watch.  It is primarily a textual product and consists of a forecaster-to-forecaster dialog.  As such, it can be very technical at times.  If a new mesoscale discussion is issued while you are en route, this may be useful information, but won't replace what you see outside of the window or what the NEXRAD image is telling you.         

     The final product is hurricane tracks.   If there's a hurricane that may impact your route, you'll definitely know that before you depart including its forecast track.  This product will only be useful for pilots flying in the Southeast and Gulf Coast states in the months of June through November with the peak of hurricane season being mid-September.  If you are not doing a lot of flying over open water in the Gulf of Mexico, Caribbean or Tropical Atlantic, then this product won't be of any significant value to you in flight.       

See the Lite

     The Aviator LT package includes county warnings, city forecasts, radar coverage, precipitation type, temporary flight restrictions (TFRs), METARs, terminal aerodrome forecasts (TAFs) and the NEXRAD mosaic.  Imagine a flight with only these products.  With careful preflight planning and a good working knowledge of the weather environment, is this enough information to justify a $30 per month subscription?       

     The Aviator package been around the longest and perhaps provides the pilot with the biggest bang for the buck.  But is it overkill?  Are you paying $20 more a month for these "borderline" products you rarely use?  There's no doubt that many pilots subscribe to the Aviator package to get ground-based lightning and perhaps forecast winds aloft.  Besides lightning and winds, included in the Aviator package are Canadian radar, AIRMETs/SIGMETs, echo tops, satellite mosaic, freezing level forecast, severe weather storm tracks, surface analysis weather maps and the two newest products mentioned above are pilot reports and severe weather watches.  Here's the $64,000 question. Do you consistently make critical in-flight weather decisions with products other than METARs, TAFs and NEXRAD?  

      It's obvious that the common denominator is the NEXRAD mosaic.  During the spring, summer and fall, there's no more of a critical piece of information than the radar image.  Some pilots claim that they absolutely cannot do without the ground-based lightning.   Really?  Try this.  Go to your computer and get on your favorite Internet site that displays a NEXRAD loop.  Do you see ground-based lightning here?  Pilots have used the NEXRAD loop for years without any lightning data and still currently make preflight decisions based on this weather product.  Unless you subscribe to a service such as WeatherTap, you won't see lightning overlaid on the radar image.  What's so magical about having ground-based lightning in the cockpit?  

     Yes, ground-based lightning is indeed very useful, especially to pinpoint areas containing embedded thunderstorms.  But is it absolutely necessary?  It would be very sweet to have a high resolution visible satellite image in the cockpit as well.  But, that's not currently offered and pilots have gotten along without it.  The NEXRAD image coupled with the view outside of the cockpit offers most of what you need to avoid dangerous convective turbulence.                

     Winds aloft that you get in the cockpit are also very coarse only displayed in 3,000-foot intervals.  They are not actual winds, but forecast winds based on a two hour RUC model forecast.  If you trust that the winds are indeed accurate, perhaps you can use these winds to pick a more favorable altitude.  In most cases, the winds just give the pilot something to play with in their boredom during the en route phase of the flight. Will they save you more than $20 per month on fuel?  That's very difficult to quantify.    

     Canadian radar has some real issues with anomalous propagation.  It tends to show precipitation that resembles thunderstorms even when the air is free of clouds.  Filters employed by WxWorx attempt mask this out, but when clouds and precipitation are possible these gross filters are not applied and anomalous propagation can be a real nuisance.  If you don't fly in Canada, there's no need for this data.  

     Perhaps the best recent addition to the Aviator package is pilot reports.  When I met with the technical staff at WxWorx a year before they announced their new subscription model and new products, I strongly encouraged them to include pilot reports in their Aviator service and not shove into their premium service to follow suit with WSI.   Fortunately, they agreed.  In addition to pilot reports, they also added severe thunderstorm and tornado watches to the Aviator package.  Both of these are fantastic products to have in the cockpit, especially pilot reports.  Once again, they were not part of the original Aviator package and pilots managed to use the package quite well without them.   

    Echo top heights can indeed be useful to determine if the area of precipitation is safe to penetrate.  Any echo tops heights over 30,000 feet often equate to deep, moist convection.  However, echo tops are often misused by pilots and can lead to false alarms.  Shown on the left are several echo top heights of 40,000 feet or greater implying the potential for dangerous convective turbulence.  However, anomalous propagation from the radar is causing these bogus echo tops to occur in a region where the highest actual tops are less than 25,000 feet.

     The infrared satellite mosaic is also a borderline product.  It will provide a more consistent cloud top height than echo tops, but doesn't show any clouds with tops below 5,000 feet.  At a 5,000-foot resolution, this product might not be of great value if you or your plane is limited to an altitude below 10,000 feet.        

     AIRMETs and SIGMETs are a time-smeared forecast and are useful more as a planning tool prior to flight.  They have less utility while in flight and can consume a lot of airspace.  Convective SIGMETs, on the other hand, are issued hourly and are definitely a borderline product on the same level as lightning.  These are most useful for depicting areas of embedded thunderstorms that may not have a classic thunderstorm signature on radar.  

     Severe storm tracks (SCITs) typically show up on cells that exhibit reflectivity values of at least 55-dBZ.  They show the direction and speed of movement, but don't always agree with reality, especially when the cells are evolving.  New development can be confused with movement causing two adjacent SCITs to point in opposite direction.  They don't typically add any additional value beyond what you already know  from studying the radar image.  

     Lastly, the freezing level is not an analysis of the current conditions.  Similar to the winds aloft, it is a two-hour RUC model forecast updated once an hour.  The resolution of the product is presented every 2,000 feet and won't likely change much while enroute.          

In a nutshell

     If you are willing to pay $20 more a month to have the satisfaction of getting ground-based lightning and pilot reports, go for the Aviator package.  Or perhaps if you live and fly in Canada, you may want the Aviator package which includes the Canadian radar data.  However, you won't gain much useful information paying an additional $50 beyond the Aviator to get the Aviator Pro service.  In this economic climate, you may have already scaled back your flying activity.  My advice would be to try the Aviator LT for a while.  Focus on improving your preflight analysis so you have to react less to what is happening around you while in flight.    
     

Did you know that most thunderstorms associated with a large scale synoptic weather system have two "forces" controlling their direction of movement?  Ask most pilots and they will typically explain that a thunderstorm moves in the same direction of the upper-level wind.  That's partly true.  Thunderstorms have two components that direct their path over the ground.  Individual thunderstorm cells within a line tend to follow the direction of the upper-level flow.  This is no different than what happens when you release a helium balloon into the air.  It will drift in the direction of the prevailing wind.  The movement of the air mass, however, also controls the motion of the storms.  A line of thunderstorms rarely stands completely still.  Its motion tends to be controlled by the movement of the air mass which tends to be almost orthogonal to the upper level flow.  In other words, if thunderstorms are associated with a cold front, the line of storms moves in the same general direction as the motion of the front.            

Consider purchasing one or more hours of online training to review the weather prior to your flight.  Using the Internet Wx Brief Roadmap, we will guide you through a detailed preflight analysis to minimize your exposure to adverse weather.  Simply send an e-mail to contact@avwxworkshops.com or call (803) 802-2591 to schedule your online session with former NWS meteorologist and CFI, Scott C. Dennstaedt.  Prices start as low as $79 for an hour or become an Elite member and you'll enjoy a 20% discount bringing the price for an hour of online training down to $63.20.   Purchase 12 hours of online training and as an Elite member you'll save $120!             

For lightning to develop within a growing convective system, the following is necessary to be present in the cloud?

• A.  Supercooled liquid water
• B.  Ice crystals
• C.  Graupel 
• D.  All of the above.  

Answer will appear in the next issue of the quarterly e-Newsletter.  

See the image to the left.  Witnessing a glory as you are flying over a cloud or cloud deck means? 

Answer:  c.  The cloud is dominated by liquid water.

A glory is a sign that the cloud below is dominated by liquid water.  When the temperature of the cloud is at or below 0°C, this could mean that the cloud contains supercooled liquid water.  Descending into such a cloud will likely result in an encounter with structural icing. Keep in mind, that the absence of a glory around the shadow of your aircraft, doesn't mean the lack of icing potential, however.  If you see what looks like sparkles around the shadow of your aircraft, this means the cloud is dominated by ice crystals an is not likely an icing hazard.  And yes, there is the possibility that you could see a glory and sparkles around the shadow of your aircraft.  In this case, the cloud is a mixed phase cloud containing both ice crystals and supercooled liquid water. 

You can also find the answer in the popular Ice Is NOT Nice - Part 1 workshop.  Order this workshop to be viewed online or we'll send you a CD-ROM ($10 shipping)!     

Here's what's coming up in our next e-Newsletter:

• Weather-related accidents:  Why are pilots still not able to avoid adverse weather?