Sure Signs of an Early Spring

In our last blog, we talked about the uncertainty of the forecast for the weekend we just finished.  Some computer forecasts were in the 50s, while others were in the 80s.  And while we didn't reach 80F yesterday (Sunday), it was clear that the warm forecasts were correct.  The cold low missed the Northwest entirely and moved into California instead.

But 76F in mid-April for Deer Park is still rather unusual.  Our average high temperature for this time of year is supposed to be in the upper-50s.  How unusual was this 76F on 14 April?  It was the warmest 14 April for Deer Park in the short 25 year history.  For Spokane airport, it was the third warmest since 1947.

Here's a table showing the date of the first 76F day in the spring and the last 76F day in the fall each year at Deer Park airport.  The average first 76F day isn't until May 3rd.  So this was a full 3 weeks ahead of schedule. 

The earliest 76F day is.... wait for it..... April 8th back in 2016.  OK, so not so exciting.  2016 also was the end of a strong El Nino, just like this year.  But only two years ago, it took us all the way until June 1st before we had our first 76F day!

If we take a look at the last 30 days for the western US, we see a pretty clear signal.  The entire Northwest has been warmer than normal for this first part of spring.

Some other indicators I've noticed of our mild spring weather.  Mosquitoes and black flies are already out, about a month ahead of schedule.  Also, my lilac buds are already starting to show.  It will still be 2-3 weeks before they bloom.  I don't keep track, but I'm pretty sure I've never had my lilacs bloom before Bloomsday, and rarely before Mother's Day.  Usually they're blooming in the latter half of May.  But not this year.

As for precipitation, we're starting to fall behind due to all of this mild and sunny weather.  The map below shows how Washington precipitation since October 1st compares to normal.  Much of Northeast Washington is now below normal.  We're not talking drought or anything, but it bears watching.

A bit more alarming is the precipitation deficit over the past 30 days.  Northeast Washington has had less than half of it's normal rainfall in the past 30 days.  In fact, just about the entire state is in the same dry boat, except for central Washington which benefited from a very wet storm around March 23rd.  As we know, these spring rains are very important.  Soils dry out quickly if not occasionally moistened by a spring rain shower.

For this week, we won't see any more days in the 70s.  Tuesday through Friday will be back in the 50s with lows dropping into the upper 20s.  This is all complements of a cold low pressure system dropping down from Alaska.

Also noteworthy on the weather map above is the really warm high pressure to our west which extends up into Alaska and northwest Canada.  This is a pretty chilly pattern for us.  Unfortunately it's also a rather dry pattern as the high pressure to our west blocks any moisture from the Pacific.  We'll see some instability showers throughout the week.  But they won't amount to much moisture.  With this cold atmosphere, we could see some graupel with these afternoon showers, with even a slim chance of a few snow flakes during the morning hours.

Then we warm back into the 60s by Sunday and throughout next week with more 70s possible then.  There will be some afternoon showers next week, but I don't see any widespread soaking rain storms at this point.

Taking a quick peek at the US and European climate models, they both suggest drier than normal conditions for our area through early May.  But then they both indicate a potential wetter-than-normal late May.  I'll keep you updated on this.