Troughzilla

Well, we had Ridgezilla, the intense area of high pressure that brought low snowpack and warm temperatures last year.  Or the persistent and powerful Godzilla El Nino.  But during the next week we will experience something different:  Troughzilla, an area of intense low pressure over the west coast that will make it cooler and wetter than normal at least through next week.

Let me show some upper level  (500 hPa, around 18,000 ft) forecast maps that document the  development of this beast.   Today was a fine day, with a modest ridge over us (see map for 5 PM today-Tuesday).   This is the last day of warmth for a while.

 By 5 PM Wednesday, a trough of low heights (or pressures) has developed over the eastern Gulf of Alaska.

 One day later (Thursday 5 PM), a very strong low center is centered over western Washington and a huge, powerful ridge over the central NE Pacific.

Friday afternoon?  Now it has grown and extended into California.

 On Saturday at 5 PM, the infernal beast is now over the entire West Coast.

As you can imagine, this pattern is not going to result in any heat waves, as illustrated by the latest forecast for Seattle from the Weather Channel. No more 70s or 80s for a while.   Temperatures at or even below normal.

Precipitation?   You bet.   For the next 72 hours, wet offshore and modest rain over our local terrain.

 

 The next 72 h (ending 5 AM Monday) is far wetter, with several inches over the mountains, lots of moisture over eastern Washington, and substantial rains over northern CA.

The atmosphere has shifted to a very different configuration, one we have not seen for a while.  Find a sweater and protect you tomatoes.