Why Don't We Get Pineapple Expresses In Summer?

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By By Steve Pool

SEATTLE - A "pineapple express" is a term for those really warm, wet storms in the winter where we get a train of moisture that stretches from near Hawaii (thus, the name "pineapple") toward the Northwest. It's usually responsible for our main flooding events.

But why not in summer? Our jet stream (which carries the moisture from Hawaii) isn't as strong in the summer time, and is also usually much farther north. Also, the differences in temperature in the mid-latitude areas aren't as large over the Pacific Ocean in the summer, so that hinders storm development.

Thus, we just don't have the ingredients together to get a strong jet stream tapping the moisture from the Hawaiian tropics and bringing it to our doorstep.

Your Photos

YouNews Sunday Images Sunday Images
These images were taken Sunday, December 14 with a Nikon D3100 and an Explore Scientific ED127 (Moon) and ED80 (M42
and M31).
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The images of M42 (Orion) and M31 (Andromeda) are short
stacks (lights only) taken Sunday evening with an Explore
Scientific ED80 (wide angle) telescope and a Nikon D3100 DSLR. The image of the moon was taken with an Explore Scientific ED127 (5-inch) refractor.