Sunday, March 17, 2013
I am anticipating a highly meridional flow to establish itself in this timeframe, in the face of a very volatile pattern across the northern Hemisphere. Excessive high pressure over the Arctic will allow for cold air masses to be forced down into lower latitudes. High pressure centered to the south of the Bering Sea and low pressure centered directly in the Bering Sea will allow for high pressure to take over the Western US. This comes as the Bering Sea low pressure extends itself down into the waters offshore the west coast of North America. The formation of the Rocky Mountain high pressure system will be helped by cycling bouts of low pressure in the Midwest, Great Lakes, Mid-Atlantic and Northeast. When these large spots of low pressure pop up in the aforementioned regions, it can be expected that a fresh dose of cooler-than-normal air will be given to many east of the Mississippi River. Based on how strong the high pressure system in the Arctic will be, I can see it possible that some isolated wintry precipitation may make its way into Florida over the next couple of weeks. That's how strong this cold air will be.
The meridional flow of the jet stream (meridional means not straight; wavy, disturbed) will allow for the jet stream to be stronger than normal at some points in the US. If a storm system manages to get into the right place at the right time, I could see a solid potential for a severe weather event in the southern Plains and Gulf Coast.
I expect dry conditions to prevail over the Rocky Mountains. This is very bad news, but the wildfire season will be influenced by this high pressure formation. If current projections hold, we could see a long-term high pressure formation over the Rockies, and this would not be good in the slightest for those in or near wildfire-prone areas.
Honestly would not be surprised to see late March allow one or two more winter weather events, possibly an accumulating snow event. Based on several other atmospheric indices I am monitoring, this snow threat would likely be confined to the Northeast and general Eastern Seaboard. The risk for Nor'easters lives on.