May 20, 2024

Winter-Like System in May

Tomorrow will not feel like late May, with a winter-like Pacific weather system making landfall, bringing lots of rain, wind, and cool temperatures.

The latest infrared satellite image shows a potent weather system moving in from the Northwest;  it will arrive around daybreak tomorrow.


The whole day should be cloudy and damp.   Here is the predicted accumulated precipitation by 5 PM.  The entire western side of the region will enjoy several tenths of an inch, with over an inch in the mountains.  Not a good hike day.


 The rain will continue into Wednesday, with the total accumulation through 5 PM reaching impressive levels (2-4 inches) in the mountains.



This torrent will have very positive implications for westside streamflow, which is now running below normal.

Consider the Snoqualmie River at Carnation. The latest National Weather Service forecast is for a rapid rise to near historical maximum levels before falling back to near normal (below).


And then there are the winds!  The approaching disturbance will cause wind gusts to 20-35 mph tomorrow afternoon and evening, which could cause some branches to fall on the newly leafed-out trees (see the latest forecast below from Seattle WindWatch.


Temperatures will only climb into the low 50s tomorrow, about 15F below normal!

I suspect May precipitation totals will end up near normal by the end of this event for most stations, making up for the dry period earlier this month.  And the good wetting will help fill reservoirs, reduce water use, and push the fire season out in time.

All and all good news.  Except for tomato plants. 😆



May 18, 2024

New Podcast: How Far into the Future Can We Forecast the Weather? and A Cool/Soggy Forecast

My latest podcast is out.

I start with the forecast, which calls for a continuation of the cool, sometimes wet, pattern of the last few days.  Forget any heatwave!

Then I discuss the issue of forecast skill.

We can now skillfully forecast for over a week and in much greater detail.

Not so 50 years ago.  What has changed?   All is revealed in the podcast.

The Decline of Forecast Skill over time for the North Hemisphere.

You can listen to the podcast below or through your favorite podcast server.


Some major podcast servers:

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Winter-Like System in May

Tomorrow will not feel like late May, with a winter-like Pacific weather system making landfall, bringing lots of rain, wind, and cool tempe...