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#1 Well, if you look at the jet stream, it is pretty obvious why North America has been warmer this winter. The jet has been dropping deeply South over the Pacific (meaning pretty COLD are over most of the eastern Pacific) and then looping way North, all the way up to British Columbia and Alaska. This is why Anchorage has a snowfall record. The storms that usually come in to California, Oregon, and Washington have been pushed Northward by this jet and are landing in Alaska and Northern BC. Because the jet is so far North, most of CONUS has been under milder air. This is not an uncommon jet flow for La Nina years. When the La Nina weakens, we will get a more "zonal" flow across CONUS in winter which will bring the storms in across the Great Basin, Rockies, and Northern plains again.
Posted by crosspatch 2012-03-25 15:15||
#2 For example, look at this graphic (flash) of atmospheric water vapor. Look at California. Notice the clouds going South to North rather than West to East. There's a storm in the Gulf of Alaska and rather than moving in to California or Oregon, it is probably going to move into BC or possibly be pushed by that jet into Alaska around Anchorage. Even the Southern jet from Mexico is going way North to nearly Montana. Everything to the right of that jet is going to have warmer than normal temperatures which explains why Omaha is forecasting 80 degrees today. That air isn't coming from the Pacific, it is coming from the Gulf of Mexico.
Posted by crosspatch 2012-03-25 15:21||
Posted by crosspatch 2012-03-25 15:21||
#4 "If you match up where that debris field is right now with where the warmer-than-normal water temperatures are, they match up perfectly".
Correllation is not causation, Mr. Margusity - any scientist should know that.
Posted by Barbara 2012-03-25 17:35||
#5 Correllation is not causation
No, but is generally a good place to start looking for causation. I would be surprised if a debris field was able to generate such a strong global effect, but I cannot say offhand it is impossible - for instance, it only takes a tap on the beaker to precipitate a supersaturated solution.
Posted by Glenmore 2012-03-25 18:01||
#6 Yeah, right now the jet streams are "loopy" going way North then back way South rather than being more "zonal" West to East flows that we have been used to seeing. This is more likely due to the switch of the Pacific Decadal Oscillation from its positive phase (roughly 1976-2006) to negative phase (since 2006). The PDO has a roughly 60 year cycle with a 30 year "positive" or warm phase and a 30 year negative or "cold" phase. The trend in global sea surface temperatures is basically negative since 2006. For the Eastern Pacific, the trend is cooler surface temperatures since 1980 and are currently below the long term average. There is no warming of the ocean in the Eastern Pacific.
Posted by crosspatch 2012-03-25 18:48||
#7 The ocean is surprisingly reflective (has a high albedo). Dark colored junk on the surface will decrease the albedo, warm the ocean surface layer and then warm the air above it.
But I'm sceptical there's enough floating junk to produce a measurable effect. Could be wrong though.
Posted by phil_b 2012-03-25 18:59||
#8 So far there is no evidence that the ocean surface IS warming and the warmth in Chicago is coming from warm Gulf of Mexico air that is being pulled North by a very "loopy" jet. The flip side of that was central Europe where an equally "loopy" jet was pulling arctic air far South over the continent causing record low temperatures. This was one of the coldest winters on record in many parts of Europe.
We had an equally "loop" pulling cold air down but it was over the ocean. If there had been an island 300 miles off the coast of California, it would have had a record cold winter this year. The jet came down at about the longitude of Hawaii, but cut East before reaching Hawaii, then cut North again near the California coast. The result was that storms did not come across the continental US but were pushed up into Alaska and Canada. They hit the coastal Mountains and when the air looped back down again over the Great Basin, it was quite dry.
Look at this representation of an Arctic Oscillation Negative jet pattern. That is what we have now. We have grown used to a Arctic Oscillation Positive jet where the flow is more West/East.
Posted by crosspatch 2012-03-25 20:42||
#9 NOt just "pretty cold" over EASTPAC but simil here in WESTPAC as Guam + Region has also received bouts of cold air.
Reminded me of some of the Mild Winters I'd experienced over the years back in CONUS.
Personally, I blame the future "GREAT SLUSHY" = GWCC ICE AGE/MINI-ICE AGE.
Posted by JosephMendiola 2012-03-25 22:23||
#10 Related: A common observation at NASCAR events is that if precipitation is in the area, often times it is delayed or never falls on the track during an event; the theory is that that heat generated by the cars creates a vortex that locally alters the wx patterns.
Posted by USN, Ret. 2012-03-25 22:57||
#11 Yes, JM. There are some COLD October-April periods coming our way beginning this year. FYI: A reliable meteorological source, who, in my humble opinion almost always "gets it right", is Joe Bastardi; formally of the politicized "Weather Channel".
Posted by canalzone 2012-03-25 22:59||