Thanks for the replies so far.
Matter of fact, we are under a tornado and or severe thunderstorm watch this afternoon so the the awnings are in!
The sensor is in an awkward position, I can't reach it from the side because when the awning is out, it blocks access to the sensor, its in about 2-3 ft in from the end.
I can't get up on the roof anymore because it seems I've developed an irrational fear of heights in the last few years (go figure after nearly 30 years in the army!).
So I guess there is no easy answer yet for me. Maybe my BIL will go on the roof for me with a hair dryer or a feed from my air compressor?
Thanks
Chris