Will changes this week bring any drought relief?

As was mentioned in the previous blog post, found here, a record dry Spring has been experienced in many locations so far.  But will the changes this week bring some rain?  We will get to that later but first let's take a look at a few updated drought maps and an imminent cool down.

Drought update

Here is a look at the latest % of normal precipitation map over the past 90 days

Some of the driest areas relative to normal since February 1st have been from the Columbia Basin into the Spokane area. The driest Feb 1st-May 15th period on record has occurred at some locations including Spokane and Davenport.  Here are a few graphs showing what has fallen so far versus the normal.  

Spokane Airport has received 1.31" of precipitation since February 1st; normal precipitation is 5.20".

Spokane observed precipitation since Feb 1st.  Green line (observed) vs brown line (normal)

Davenport: Observed: 0.60" Normal 4.21" 

Davenport observed precipitation since Feb 1st.  Green line (observed) vs brown line (normal)

Let's look at one more site - Ephrata.  The 2nd driest period has been recorded with only two days of light precipitation since February 15th.

Ephrata: Observed 0.36" Normal 2.24"

Ephrata observed precipitation since Feb 1st.  Green line (observed) vs brown line (normal)

The dry conditions this spring have not been good for the spring wheat crop.  The map below shows planting areas of spring wheat (by county) with drought areas overlayed

And this is a big increase over the past 3 months because of the dry weather.

Changes ahead

So our region needs some rain!  The weather pattern this week will change as low pressure sets up near the region.  We are confident that temperatures will cool significantly Tuesday and Wednesday with highs Wednesday dropping into the upper 50s and 60s.  Here is one model projection showing the cooler than normal temperatures over the area.

12z/May 16th GEFS 2 meter temperature anomaly (deg C) valid 5 PM PDT Wednesday, May 19th

But will we get some rain?  It looks like there will be an increasing chance mid to late week as bands of showers rotate counterclockwise around a low over Oregon.  Below is one model showing the low position on Wednesday with the green areas showing elevated moisture content and thus the greatest chances of showers over the Idaho Panhandle and Cascades.

12z/May 16th GFS 500mb heights and 700-500mb Relative Humidity valid 2 PM PDT Wednesday, May 19th

On Thursday into Friday the low drops south, but bands of showers rotating around the low may give parts of our region additional opportunities for some rain.

12z/May 16th GFS 500mb heights and 700-500mb Relative Humidity valid 11 PM PDT Friday, May 19th

There is high uncertainty as to which areas get rain, and how much.  But at least it's a change and an opportunity for rain.  Stay tuned for forecast updates this week as we monitor the track of the low and the showers associated with it.