If you noticed (sometimes the pilot will mention things like this), as you
were coming in to Dallas, you would have seen a distinct visible division
between the subtropical air over Texas and the polar air to the north.
What you experienced is called in "folk speak" in Texas a "blue norther,"
or sometimes a "blue tailed norther" if there was a cloud bank along the
front, followed by the clear polar air.  A thirty degree temperature drop
when the front passes is not unusual, though the 5 below the next morning
would have been.  I'd bet that the relative humidity when you were sparking
was below 10%, and that the sky was the color of a robin's egg.

On Thu, Jan 4, 2018 at 12:37 PM, David Beierl <dbeierl@attglobal.net> wrote:

> The all time record low in Dallas is 8 below F, and lows in the teens are
>> regular
>> events in December and January.
>
>
> I went to Dallas once to exhibit at the Crystal Palace.  Outside temp when
> we landed was 60F.  While we waited for a gate I watched all the old paper
> cups etc by the taxiway suddenly leap into the air and vanish.  By the time
> we got off the plane it was 30F out and the next morning IIRC it was five
> below.  The place was in shock.  I set up the machines for the show with a
> thirty foot open loading door a hundred feet away, drawing sparks off
> everything I touched.
>
> Yrs,
> d
>