Rainshadow on the Wrong Side of the Olympics

As shown below, the Olympic rainshadow is normally on the northeast side of the Olympics, while heavy precipitation is found on the south and southwest side of the barrier.

This configuration is due to the typical southwesterly (from the southwest) winds approaching the barrier during the cool season, resulting in upward motion (and precipitation) on the windward (SW) side and sinking motion (and little precipitation) on the leeward (NE) side.

But something unexpected happened on Tuesday morning.   

The weather radar indicated precipitation in the rainshadow area, with nothing apparent on the southwest side (see below, there is some ground clutter on the SW side from the radar beam hitting some peaks).

A cloud band was quite evident to the north of the Olympics that morning.

Rain gauges picked up modest rainfall north of the Olympics, with precipitation on the dry-sky lovers in Sequim and vicinity.  Surely unwelcome for those hitting the links that morning.

The origin of this backwards situation?   The low-level winds had reversed, with northerly wind approaching the Olympics from the north (see surface wind below).

This situation was associated with high pressure to the north and low pressure to the south (see below), with the wind blowing from high to low pressure.

We will be dry until the middle of next week, after which the atmospheric spigot turns on in a major way.