AIRCRAFT ICING

In light of the recent crash at Montrose, Colorado,  the NTSB issued an "Alert Letter" related to airframe icing and frost accumulation.  You can view the letter here.   It recommends a tactile inspection of surfaces prior to departure, as opposed to just a visual look-see.   Even a layer of frost the width of fine sandpaper can cause significant loss of lift.  More information on icing from the AOPA can be viewed here. 

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  This is a view of what controllers see as weather echoes on their scopes.  The system is called WARP and provides four levels of information ranging from light (<30 dBZ), moderate (30-39 dBZ), heavy (40-49 dBZ) and extreme (50 and > dBZ).   En-route controllers do not show light precipitation on their scopes.   Terminal controllers may have slightly different presentations, but all FAA controllers will use the word "precipitation" behind any category (eg, moderate precipitation).   Meteorologists at CWSUs or other NWS offices are now prohibited from using the term "level" or "VIP level" when describing thunderstorms or other precipitation and will use the above terminology when describing intensity.

Outflow boundaries (gust fronts) are seen on this animated GIF files eminating from thunderstorms in southern Florida.  When flying through these features the pilot might notice a band of low clouds, or perhaps a shelf cloud.  Stronger gust fronts may contain roll clouds indicative of hazardous shears.   Colliding outflow boundaries as seen here can sometimes provide the trigger for new thunderstorm development.