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Wet March fuels discussion of climate shift

Wet March fuels discussion of climate shift

by KGW Meteorologist Rod Hill

Bio | Email | Follow: @kgwrodhill

kgw.com

Posted on April 2, 2014 at 9:10 AM

Updated Thursday, Apr 3 at 3:02 AM

PORTLAND --  Our wet March weather is yet another reason to believe Portland's rainy season could be on the move from winter into spring. 

A few years ago I did a comparison of recent rainfall from November through February to the spring months of March through June.  The result was a nearly equal average, meaning spring months over the past decade are seeing nearly the same total amount of rainfall as winter as well as the a near equal number of days with measurable precipitation. 

What caught my eye and inspired me to write this article was the number of top 5 wet spring months in the record book.  A record book that has simply been re-written since 1980. 

You will notice when looking at the top 5 wet months for March, April, June and May,  all but four years have occurred over the past three decades.  In other words, 16 of the wettest 20 spring months on record for PDX have recently taken place.  In fact, 7 of the wettest months have occurred since the year 2000.  

The month of March has seen a dramatic increase in rainfall average over the past 10 years and is on average Portland's 4th wettest month during a typical calendar year. 

To be fair, the PDX record book only dates back to 1941, meaning you could make the argument that the first 40 years of record were actually under value.  However, it is undeniable that recent decades have seen a consistent increase in spring rain. 

It is also important to note that overall Portland rainfall has declined.  I am noticing a shift of the heaviest rainy season, not an increase in total moisture overall.

KGW Meteorologist Rod Hill, follow me @

www.facebook.com/kgwrodhill

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