Rain Storm Recap

The cold front moved through overnight to bring an end to the steady rain.  A rather wet 3 days that we'll put into context in a minute.  First, here's a map of the 72 hour rainfall totals (Monday morning to Thursday morning, 4-7 Dec 2023).

Obviously western Washington received the most rain.  But you can also see that northeast Washington and north Idaho picked up some impressive totals as well.  It's pretty easy to see where the Atmospheric River was pointed.  But this area is also favored when the flow pattern is from the southwest, as it was in this situation.

A closer zoom of the area shows some interesting details worth noting.

• Deer Park airport picked up 2.74" while Spokane airport received only 1.34".
• Big Blue RAWS (on the Spokane reservation) received 3.78".
• The wettest observation is 9.00" at Hidden Lake SNOTEL (5000' elevation) west of Bonners Ferry.
• Bear Mountain SNOTEL (east of Sandpoint) had 6.50".
• Bunchgrass Meadows SNOTEL (east of Ione) picked up 5.10".
• Mount Spokane had 4.70" of rain.  Most of their snow melted, but the rain had changed back to snow this morning.

So there's a few ways to put this event into perspective.

• For Deer Park airport, this 3-day total of 2.74" was 
• the third wettest 3-day event since records started in 1998
• equal to the normal rainfall for the entire month of November
• equal to 12% of the total average precipitation for the year.
• For Spokane airport, the 1.34" doesn't even rank in the top 50 events.

The 9" of rain at Hidden Lake actually didn't even bring them back to a normal precipitation for the water year (which starts 1 October).  This graph shows the observed precipitation for this year (black line) and the normal (green line).  You can see the sharp rise in the black line over the past few days.  But even after all that rain, it's still a little below the green (normal) line.  This shows how dry our fall and early winter have been so far.

Since our ground was frozen before this rain event, some of the rain ran off into the streams and rivers, headed for the Pacific Ocean.  The Little Spokane River saw a decent rise of a little over a foot.

Moving forward, after some cold frontal showers today, we may see some snow showers overnight tonight.  Friday should be mostly dry, as will most of Saturday.  Snow will arrive late Saturday afternoon or evening and should end early Sunday morning.  Another weather system will quickly move in later Sunday morning.  This could bring rain or snow to the Spokane and Deer Park areas, but should be all snow for the northern areas of Washington.  We'll probably get around 2-3" of snow from this system in the Spokane area, but the northern valleys could see 6" or more.  All of the rain and snow should end by Monday morning.  Tuesday through Friday of next week looks dry and cold with lows in the 20s and highs in the 30s.