The Blob Strengthens

It is a story worthy of a 50's science fiction movie.   A strange phenomenon brings danger and fear to society.  Without warning, it disappears.  But then, unexpectedly it returns to an anxiety ridden population.

But this time it is not science fiction.  It is not a story.  It is real.  The BLOB has returned.  Naming it is easy:  THE SON OF BLOB.

The original BLOB, named by Washington State Climatologist Nick Bond, formed the previous winter (2013-2014).   The BLOB was defined as a persistent region of anomalously warm water in the northeast Pacific.  With the air reaching the Northwest generally passing over the BLOB, the result was warmer than normal temperatures.

A good way to follow the development of this fiendish climate anomaly is to view maps of sea surface temperature  (SST) anomalies (differences between the actual temperatures and normal conditions).   Below and to the left, you see SST anomalies averaged over a week, one year ago.   The blood red color of the BLOB is apparent over the NE Pacific.   But by the beginning of November, the BLOB had weakened, while warm water developed along the coast.  Such a pattern is reminiscent of El Nino conditions...and in fact, El Nino was strengthening.

By February, the warm water was strengthening and extending westward. Enough to bring fear and concern (left panel below).  And by the first week of this month, the BLOB seems to have returned, and with it, its evil twin, El Nino, indicated by the warm waters in the eastern tropical Pacific.  Now we have a problem.  Note that the temperatures in the BLOB are 2-3 C (roughly 4-5F) above normal.

 The effects of the BLOB have become more than a little evident to everyone living in our region.  Temperatures are way above normal because of the warming effects of the ocean...it is hard for our minimum temperatures to fall much below the ocean temperatures this time of the year.  Want to see evidence of this?   Here are the surface air temperatures at Seattle Tacoma Airport for the last 4 weeks, with the average highs and lows shown.   We have been warmer than normal, with minimum temperatures consistently 3-4F above normal.  An accident?  Or the BLOB?

Our seasonal weather models know all about the warm sea surface temperatures associated with the BLOB.  What do you think they are predicting for this summer?  Let me show you the latest seasonal forecast from the NOAA Climate Forecast System forecast.    Warmer than normal along the West Coast by 1-2C (2-4F).

The BLOB itself is not an independent player.  It has been forced by an anomalous atmospheric circulation, including anomalous high pressure (ridging) centered north of our region (see map showing the height (pressure) anomalies (difference from normal) at 500 hPa (about 18,000ft) for the last 30 days.  Yellow indicates higher heights than normal.

So get out your shorts, secure an extra fan, the BLOB is back and its not going anywhere soon.

 PS:  There WAS a movie Son of Blob and you will never guess who directed it (to his eternal embarrassment).  Larry Hagman of Dallas and I Dream of Genie Fame.