Subtropical Moisture, Record Lost, and Thank You

First, the thank you.   I very much appreciate the contributions of over one hundred of you to my weather research fund.   It has allowed me to fill in the financial holes for running the local weather prediction modeling research, helping to make up for losses as funding agencies reduce support.  Furthermore, I am dedicating $2000 of the support for an undergraduate Weather Research scholarship.  As an instructor and the department's undergraduate adviser, I see first hand the impact of the rapidly rising UW tuition, with many of our undergraduates acquiring large debt levels and working more and more hours--leaving less time for study and sleep.  The most extreme case of this was one student that kept on falling asleep in my junior synoptics class.  I talked to him one day about it...turns out he was supporting himself by fueling jets at Sea-Tac airport overnight!  Anyway, as long as the contributions come in I would like to continue using a portion of the funds for scholarships.  And thank you to all of you that have sent me tips and suggestions about my lost dog Leah.   She is still roaming around Mountlake Terrace and it is maddening that we have not found her yet.

Today, it was warm, moist and balmy---the warmest and wettest day in over a month.  Many locations in western Washington reached the mid-50s, as subtropical, southwesterly flow surged into the region.  As apparent from this satellite-based vertically integrated water vapor content image, the moisture plume did not come from near Hawaii, but pushed westward and northward across the north-central Pacific (purple and red, highest values, followed by orange and yellow).  This is a modest atmospheric river with origins in the subtropics.

The plume most directly intersected the coast south of Washington on the northern Oregon coast, and thus the higher precipitation amounts were to our south.  Here is the 24-h precipitation totals ending 9 PM on Wednesday.  Values ranged from a trace (.01 inch) in the middle of the rainshadow NE of the Olympics to 3-5 inches on the western slopes of the Olympics, coastal mountains and Cascades, with particularly large amounts over NW Oregon.  Talking about rainshadows, amazing low values in eastern Washington (trace to a few hundredths of an inch).

And as long as we are talking rainshadows...here is a radar sample during the early afternoon, when the shadow was centered near Everett.  You got to love living around here---you can be completely dry at one location, but pouring a short car drive away.

A weak disturbance comes in later tomorrow (Thursday), a stronger system on Friday, and believe it or not, a relatively dry New Year's weekend is ahead.  A very normal situation.

Finally, the rainfall today has prevented Seattle from enjoying the driest December on record---we did have the driest first three weeks on record, though.   But the drought and the west coast ridging that produced a mainly dry December has resulted in the western U.S. snowpack being well below normal. Here is the latest snow water equivalent chart, giving the % of normal. Washington is now mostly 70-100% of normal, Oregon about 50% of normal, and the CA Sierras down under 20%.  Want above-normal snow?   Head to Arizona and New Mexico!