Snow in the Forecast - for mid-April

 

Although the triple La Nina is officially over, the atmosphere is still looking rather La Nina-like in the Inland Northwest.  La Nina usually brings cool and wet weather to the Northwest during the spring months, so this is somewhat expected.  For the first half of April, temperatures in Deer Park were 2.7F below normal.  The figure below shows the daily temperatures at Deer Park Airport since Jan 1st.  The blue bars are the daily high/low.  The brown shading is normal, the red is above normal, and the blue is below normal.  As you can see, the blue bars have been hanging out more in the below-normal range than the above-normal.






Precipitation for April so far has been 0.43" above normal at Deer Park.  But this actually followed three drier-than-normal months of January through March.  For the Water Year (which starts October 1st), Deer Park is drier than normal by nearly 2.5".  So while the wet April may be frustrating to farmers, we actually need the moisture.  



The entire Northwest has been dry this winter, with the exception of north-central Washington.  I know that sounds odd, since we had so much snow this winter.  But snow alone can't give us all of the moisture we are supposed to get. And we only had one good winter rain event this past winter.

How does this spring compare to past springs?  One way to evaluate it is the number of days of 50F or warmer.  Here's the total for Jan 1 - Apr 16 since 1998.  As you can see, we've only had 20 such days this spring, which is the lowest total since 2011.



So what weather do we see coming up for the near future?  A large cool air mass will be moving into the area behind Sunday's rain event.  Temperatures will be well below-normal throughout this week.  (Deer Park temperatures at this time of year are a high of 60 and low of 33).  Morning temperatures could dip into the lower 20s by the middle of the week, with highs not even reaching the 50 degree mark.  So rather chilly for the second half of April.

A cold front will move into the area on Monday night.  Depending on the timing, don't be surprised if you wake up to a little snow Tuesday morning, even in the valleys.  The best chance for snow will be in the northern ID Panhandle and extreme northeast Washington. The rest of the week will the usual afternoon rain, snow and graupel showers.   But precipitation amounts will be light, so there won't be any mud or standing water.  Another weather system on Friday morning could also bring some accumulating snow to the Inland Northwest.

By the weekend, temperatures will warm back into the 50s, but still below normal.  Wet weather will continue.  Right now the weekend looks to be a repeat of the past two weekends, with drier weather on Saturday and then a good chance of rain for Sunday.  

Next week doesn't show much change.  It won't be as cold as this week, but it also won't be sunny and dry.



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