have a weather system that has its origins from the Hawaiian tropics (Get
it? 'Pineapple' for Hawaii? Who said weathermen don't have a sense of humor?)
You can usually see it on a
satellite photo, where the band of rainfall stretches from the Pacific
Northwest all the way southwest to near Hawaii.
These tend to be the wettest-type of
storms we get around here -- bringing between 1-2" of rain per day for
Seattle and much more near the mountains -- as it has an abundance of warm,
It also brings high potential for
flooding, as the warm air tends to raise snow levels quite high around here.
That has two compounding effects:
1) It means precipitation falls as
rain instead of snow in the mountains, increasing the run-off into the local
2) It will also begin to melt the
snow at lower mountains altitudes, adding even more liquid water into the
Pineapple Expresses usually mean
wintertime temperatures in the upper 50s or warmer. I remember a December
night in the mid 1990s when the temperature reached 63 degrees -- at 2
a.m.(!) -- during a Pineapple Express event.