Will astronomical spring arrive on schedule?

Everyone wants to know when the cold spell will end.  With another day of below normal temperatures today, our current streak of below normal temperatures will reach 34.  This number will continue to grow but could astronomical spring actually arrive on schedule?  March 20th marks the official first day of spring.  What does the weather pattern look like as we approach this date?  And what is our normal temperature anyway?  Let's dive into it.

Let's begin with this weekend.  Here is a plot of temperature anomaly on Saturday from one model.

12z/Mar 7th GEFS forecast of 850mb temperature anomaly valid 4 PM PST March 9th.

 You can see lots of blue over our region indicating the continued cooler than normal temperatures over all of the west.

But changes may be in store come later next week.  Here is what the GFS model shows for Thursday, March 14th.

00z/Mar 8th GFS model forecast of 500mb heights and 250mb winds (image) valid 4 PM PST March 14th, 2019

You can see an active jet stream in the west and central Pacific but high pressure starting to build near our neck of the woods.  High pressure typically brings milder temperatures in March but this will take some time. The snow cover, and melting snow will likely provide a favorable environment for night time fog development especially in the early stages of this ridge which should keep the actual warming tempered with below normal temperatures favored to continue through next week.

March 17th Pattern

What about further out?  This model shows high pressure becoming stronger March 17th.

00z Mar 8th GFS model forecast of 500mb heights and 250mb winds (image) valid 4 PM PST March 17th, 2019

This solution would support a warming trend, but again in the lower elevations fog and low clouds could limit the warming to some degree.  But we are getting now into mid March, and the sun angle favors low clouds not lasting through the day and the lower level cold air should moderate.

But one model solution 10 days out can easily not pan out.  So we need to look at other models and what are called ensemble forecasts to get a better idea of possibilities far out into the forecast.

Let's look at the Canadian Ensemble Mean forecast first for March 17th.

12z Mar 7th CMCE forecast of 850mb temperature anomaly valid 4 PM PST March 17th.

Whoa!  This model shows temperatures (at least in the mountains) warming to slightly above normal.

What about the GFS Ensemble mean (GEFS)

12z Mar 7th GEFS forecast of 850mb temperature anomaly valid 4 PM PST March 17th.

This solution isn't as warm keeping our temperatures slightly below normal.  But just slightly, with temperatures warmer than they are now.

March 20th - First day of Spring

Now we are really getting far out into the forecast.  Models usually aren't very reliable this far out but sometimes the model ensemble means can give a glimpse of where the warm and cold anomalies may set up on a regional scale.  What are the models showing?  We will start with the Canadian Ensemble Mean again.

12z Mar 7th CMCE forecast of 850mb temperature anomaly valid 4 PM PST March 20th.

Haven't seen these colors in awhile.  The Canadian Ensemble Mean has a warmer than normal air mass over us.  What about the GFS Ensemble Mean?

12z Mar 7th GEFS forecast of 850mb temperature anomaly valid 4 PM PST March 20th.

Wow, seeing some warm colors from this model (above) as well.

Now looking at the latest 8-14 Day Temperature Outlook (image below) from the NWS Climate Prediction Center (CPC) there is a favorable trend toward warmer temperatures along the west coast and chances of having colder than normal temperatures are less.  It looks as if the cold anomaly that has had much of the U.S. in its grips is moving farther out of the west giving the region a break from well below normal temperatures.




Precipitation looks to have a better chance of being minimal going into the middle of March.




So, you may be asking what is normal for temperatures in this region?  After all we've been below normal for a little over a month.  Here are the normal highs for the first day of spring

March 20th normal high temperature

Wouldn't these temperatures be pleasant?  The increasing March sun angle is in our favor.  Maybe we will get there around the first day of Spring or shortly after.