Saturday, June 8, 2019

Snow in the Cascades, Thunderstorms, and Needed Precipitation over SW Washington

Friday was quite a weather day, as a cold upper level low pressure area brought convective showers and thunderstorms to large portions of Washington, while snow fell over the higher terrain of the Olympics and Cascades.

The parking lot this morning at the Paradise visitor center on Mount Rainier (at ~ 5000 ft) says it all.  Looks like a winter wonderful up there.


The visible satellite image at 5 PM Friday showed the very active pattern, with lots of showers over southwest Washington ,with some extending into southern Puget Sound


The precipitation totals over the past 48 h have been impressive, with 1.5-2 inches over the western side of the Cascades and up to 1.5 inches in the mountains of southwest Washington (see below, click on image to expand).  Central Puget Sound was a bit rain-shadowed by the Olympics.



This precipitation was extremely well positioned, wetting down some of the drier areas of the state--the coast, SW Washington, and the western side of the Cascades, something illustrated by the percentage of normal precipitation during the water year so far (see below).  Southwest WA, the western Cascade slopes, and the coast has been the focus of our recent dry conditions, and that was exactly where the most rain fell.

The rain over SW WA had really helped with the streamflow there, returning much of that area to near normal streamflow conditions. (see map)


A good illustration of that is the Chehalis River at Doty, where a below-normal streamflow has risen to near normal:

And what about lightning?    During the 24-h ending 1 AM Saturday, there were several strikes in SW  WA, and many more in Eastern WA.   Few in the Cascades, which is good from a wildfire viewpoint.


We are about to go into a warmer, drier period, with temperatures zooming up into the mid-80s by Wednesday.    There will be some precipitation north of us earlier in the week, which is fortunate--it will keep the BC wildfires down.

Finally, I will end with a treat:  a very nice video of the weather action on Friday from Skunk Bay Weather's video cam looking northward from the Kitsap Peninsula.  You will see how the atmosphere becomes less stable during the day as the surface heats up and the upper trough approaches.  Cumulus clouds develop at low-level initially and then a number of cumulonimbus clouds rev up, including the development of anvil clouds.  Really beautiful.

Turbulent Sky - June 7, 2019 from SkunkBayWeather on Vimeo.






8 comments:

  1. Regarding the Chehalis River discharge plot. Like many of our west side rivers, such as the Samish where I live, that one falls back off to where it started in about a week or so of no rain - which is what will happen now. You can find that online gauge and change the duration along the bottom to see that situation.

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  2. Very nice video. I'm jealous of the rain everyone got (except Winthrop). We got nothing. The surrounding mountains appeared to get some rain but not enough to increase the flow on the Chewuch river (north of Winthrop). The Chewuch river flow has now dropped well down into the 25th percentile. Not at all promising for our irrigation season. So yes, I think the drought emergency is appropriate for our river basin at least.

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  3. Freezing conditions can directly affect streamflow, and low flows during cold periods are sometimes (dare I say "often") misinterpreted as "dry conditions" and "lack of water" when frozen banks may have stopped or stalled runoff and baseflow. I just ran local stats to post a condition report at CoCoRaHS. In the last 30 days (including today) 16 of 30 days have been rainy, with 2.84" precip at my valley location. Our overnight lows have been mostly in the 30s-40s, with new snow in the mountains above us twice. The rule of thumb for altitude temperature drop is something like 3.5 degrees per 1000 feet. Of course, the atmosphere isn't static; I have no way of knowing if air currents on high are cold or warm. But my point here is that instantaneous "low flow" gauge measurements can be misleading in respect to overall water-watershed conditions.

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  4. Boy oh boy I bet that governor isn't happy about this. "What happened to my crisis?!"

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    1. I not impressed by "that gov". No chance to win and burning jet fuel on his carbon rich campaign trail. And I voted for that guy, twice.

      https://www.kuow.org/stories/gov-jay-inslee-says-he-s-the-climate-candidate-so-let-s-look-at-his-record.

      "Inslee has signed a pledge to take no campaign contributions from the fossil fuel industry, though he has a cozier relationship with another major polluter, the aviation sector.

      Inslee gave the state's largest private employer, Boeing, an $8.7 billion tax break, the largest corporate subsidy ever by any U.S. city or state, in 2013, and he excluded jet fuel from his proposal to tax the carbon in electricity, gasoline and natural gas."

      Chris H.
      Heli-free North Cascades

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  5. Got zilch on Lummi Island. Very disappointing. I'm glad for all those who were luckier. Thirsty birds are coming to birdbath non-stop, for drinking & bathing. Garden plants unenthusiastic about lush growth (at least I have clayish soil, which holds some moisture down a few inches). I'm already using as little inside water as possible & tossing used dishwater on shrubs etc. Oh well. Maybe next time ... like in August or September?

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  6. Rabbit Guy- yup- the Chehalis river is dropping back down- and still well beneath the 64 year median values for this time of year.

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