Rainfall Totals From the Last Few Storms

Monday, April 8, 2013
1:02 P.M.

Photo credit: Wikimedia user "Rosendahl"

April is known for "showers and sunbreaks," which might as well become a trademarked phrase around here since it is probably the most commonly mentioned phrase in Seattle, meteorological or otherwise. Imagine how rich the original creator of that phrase would be if news stations and the National Weather Service had to buy rights to use it. That'd be an easy way to make a living.

This past weekend, though, we saw more showers than sunbreaks. In fact, we saw half an inch of rain on Saturday and an incredible, record-setting 1.54 inches of rain on Sunday. Scott Sistek of KOMO News (hands down the best station for weather news in Washington... nobody else even comes close) found that the 2.04 inches of rain that Sea-Tac saw this weekend made it the wettest April weekend since record-keeping began in 1948. Sunday was the fourth-wettest day ever in the month of April at Sea-Tac, and we absolutely demolished the previous record of 0.63 inches in 1984.

As of midnight Sunday, Sea-Tac has received 3.10 inches of rain for the month of April, which is over four times the normal amount by this date (0.74 inches) and slightly higher than the average total for the entire month of April, which is 2.71 inches. I have to give Scott Sistek and the KOMO weather page credit for these statistics... they are in the public domain, but the folks at KOMO sure saved me a lot of time searching for statistics. Scott's article can be found here, on his "Partly to Mostly Bloggin'" blog, which is only bested by my blog in terms of quality of information, writing skill, and overall content. Just kidding, his blog makes mine look like it should be drawn in crayon.

The artist was 1 year 10 months when this was drawn. Soft crayon on paper. Uploaded by parent. Photo credit:Wikimedia User "Monika Wirthgen/Menschliches"

The University of Washington is one of the premier schools in the galaxy for studying meteorology, and they've developed a nifty little tool called "Seattle RainWatch" with the Seattle Public Utilities. Here are some 72-hour rainfall totals over the area as estimated by the Camano Island WSR-88D radar.

72-hour precip from 11:56 PM 4/4/13 to 11:56 PM 4/7/13

Remember, this precipitation map is the precipitation as measured by the radar. The radar beam increases with height as it radiates outward from the Camano Island radar, so those places to the far south and west likely got more precipitation than the radar is showing. Also, you can clearly see the blocking effect that the Olympics and Cascades have on the beam in the above photo. In any event, there are extremely heavy 3-day precipitation totals over the region for April... it looks like some mountainous regions got over six inches during this span.

Here's another RainWatch graphic that is zoomed in on the Seattle area.

72-hour precip from 11:56 PM 4/4/13 to 11:56 PM 4/7/13

This graphic really shows how the precipitation was not evenly spread over the Puget Sound lowlands, especially the Seattle area. These look like slight over-estimates to me... I checked the UW rooftop data from the atmospheric sciences building and they only officially received ~2 inches for the period. Still, it gives a good general idea of the relative amounts of precipitation that fell over the area. It's interesting to note how much of Mercer Island and SODO was relatively drier than places north and south.

Will the wet weather end? No. I do not see any storms like the one we saw this past weekend on the horizon, but we do look to settle into a cool, unsettled pattern with showers, sunbreaks, and relatively low snow levels for this time of year, easily below pass level. It should be a great time to get some late-season turns in. I personally recommend the Alpental backcountry. Wait, nevermind, I don't want anybody messing up the perfect powder for me.

On another note, this is the time of year when we really start to see severe weather pop up in the nation's heartland. Joey Sipos snapped the below picture yesterday on his storm-chasing adventure in the middle of Kansas. Makes our storms look pretty pathetic.

Enjoy this period of extended chilliness while you can, because it ain't gonna be around forever.

Have a good one!
Charlie