Perhaps, you already know about our red menace, a large area of warmer than normal sea surface temperatures over the northeastern Pacific. You can see the strengthening and extension of the BLOB in a series of temperature maps over the eastern Pacific, with the shading showing the differences of the sea surface temperatures from normal (yellow to red are above normal in degrees C).
During the last week in March, there was warmer than normal temperatures offshore, but near normal just off of the entire West Coast.
By late April, the warm blob had strengthened considerably, with an extension reaching the California/Oregon coast.
And last week, the warmth really surged up and down the West Coast, including off the Washington Coast, which was roughly 1-1.5C (2-3F) above normal
From past experience, we have learned that warmer than normal Pacific ocean temperatures tend to increase the minimum temperatures west of the Cascade crest. If you are leaving in western Washington, western BC or western Oregon have you noticed the morning warmth?
If not, let’s check it out! Here is a plot of the temperatures at SeaTac Airport for the last 12 weeks (red line), with the normal highs (purple line) and lows (cyan line) also shown. During the past month, the low temperatures have rarely declined to the normal lows, being around 3F above normal. You don’t see that behavior back in March.
Quillayute, on the northern Washington coast, shows the same warm minimum…just more so. That makes sense–it is right near the Ocean.
In contrast, moving over to eastern Washington, where the marine influence is weaker, shows far less impact of the warm water, as illustrated by the temperatures at Walla Walla.
As long as the BLOB-related warm water along our coast sticks around, our minimum temperatures each day will be several degrees above normal. Being BLOB-savvy I took advantage of its moderating effects and put in my tomato plants early. They are quite happy and growing well.
How long will the BLOB last? That will be a topic of a future blog!