Sunday, July 27, 2014

No Precipitation over the Next 8 days

Here in the Northwest, we are now going into the  climatologically driest period of the year, with July 29 being the most arid day on average.

One of my favorite plots is the forecast precipitation over the next 8 days, in this case from the National Weather Services's GFS model.  Take a look at it.

 Completely dry over Washington, making us probably the driest state in the union.

 The desert southwest, particularly Arizona, N. Mexico,  and Colorado are quite wet as the SW Monsoon is at its height.   Alaska is wet, with rain spreading south into central BC.   The thunderstorm-ridden eastern half of the U.S. is quite moist, with particularly heavy precipitation along the coast. Some thunderstorm in eastern Oregon and perhaps a few of them might slip into eastern Washington.


The NOAA/NWS Climate Prediction Center's 6-10 day temp forecast is for much warmer than normal temperatures over the West Coast, but much cooler than normal over much of the eastern half of the U.S.



The origin of this persistent pattern?   A major ridge of high pressure over the Rockies and troughs over the eastern U.S. and the gulf of Alaska.    Here is the upper level map (500 hPa, about 18,000 ft) for Thursday night (120 hr forecast).


So wonderful weather for recreation and Seafair during the next week. Perhaps for hiking, boating, and whatever you like.

But we are setting ourselves up for a another wildfire outbreak as the surface dries out.

 Eventually, this pattern will break down and with it will come thunderstorms and strong winds pushing across the Cascades.

1 comment:

John Bower said...

Your blog is the best ever! Your succinct treatment of the Pacific NW as a climate change refuge is the best information in a short treatment of the subject that I've seen. The humor at the end is great too (the fence), except that like so much humor, it avoids taking the question seriously. I realize it is out of your field of expertise to consider the effects of the millions of climate change refugees who will likely be on the march, but do you think it is fair to say that the effects of a massive migration to the NW is the biggest thing we have to worry about from climate change in our region?