Welcome onboard.
Interesting location, at first glance I thought it was my own post.
I would suspect the same problem, and if correct, it will be getting progressively lower on your gauge as weather cools. You might want to consider a wp change at the same time if you are aware of their reputation.
Here the story of a fellow owner:
http://www.contour.org/ubbthreads/showflat.php?Cat=&Board=general&Number=31677&page=0&view=collapsed&sb=5&o=31&fpart=1
