It simply doesn't go away. It may get knocked down for a day by a weak ridge...but it just pushes back up. The vampire of weather patterns....but there is no silver bullet or wooden stake to stop it.
If only meteorologists had similar equipment for dealing with ridges that refuse to die.
But over the eastern U.S., the resulting downstream trough forebodes unusual cold and snow.
So, lets look at a series of upper level (500 hPa) weather maps from the National Weather Service GFS global model. The solid lines are height lines; where they buckle up to the north there is a ridge and where they push southward, a trough. Wind are also shown.
Today at 4 PM PST. Big ridge over the West Coast, trough over the eastern U.S.
Friday night (10 PM) is the only break form ridge-land, as a weak trough pushes down the ridge over the NW, resulting in a few light showers overnight. Still a warm pattern.
Sunday morning, the ridge is back in force. Active trough in the east and a major snowstorm over the Northeast.
Other modeling systems (like the European Center and the Canadian Meteorological Center) are going for the same persistent ridging over the West. Ensemble systems (many forecasts made at the same time) show the same thing. Our confidence in this forecast is very high. The implications for those of you who enjoying hiking, biking, and sun bathing are very positive. The garden centers are stocked for the inevitable crush of folks getting the itch to weed and hoe. For skiers...well, lets skip that part.
The NOAA Climate Prediction Center 6-10 day forecast is consistent with the above, with extraordinary cold predicted over a huge area of the eastern U.S. Dark blue means great confidence in below normal temperatures.
I can not stress enough that there is no reason to expect that this has anything to do with global warming. And those in the eastern U.S. should not be claiming that it is proof of global cooling. In fact, some of the latest research (example here) provide strong evidence that the pattern of western ridging is the result of natural variability. It is not unprecedented.
Several of you have emailed protests to me, pushing a theory that global warming causes weakening of jet streams that then meander more. This is a completely discredited theory. Observations show the jet stream is NOT weakening, global climate models do NOT show more meandering jet streams as the earth warms, and the papers claiming this mechanism (e.g., Varvus and Francis 2012) have fatal flaws. Other research has shown that sea surface temperature anomalies can produce such atmospheric ridging. And the origin of the blob of warm water off our coast during last year--that was caused by the ridging.
Too many climate advocacy groups are weakening their credibility by pushing an anthropogenic global warming origin of this event.
I will talk more about such mechanism in one of my next blogs.
KPLU Climate Talk
If you want to hear me talk about the regional implications of global climate change in some detail, please come to my UW Kane Hall talk on March 11th.Sponsored by local public radio station KPLU, tickets for this event can be secured at this web site.
Interested in attending the big local weather workshop of the region? The Pacific Northwest Weather Workshop will be held in Seattle at the NOAA facility on February 27-28th. Everyone is invited and the majority of talks are accessible to laypeople. To attend you have to register or they won't let you in the gate. There will be a major session on the Oso landslide. There is a registration fee that covers refreshments and food, and special student pricing. If interested, check out this website.