Despite an ongoing El Nino, the Walker circulation has remained at near normal strength, and the dominant storm track has been from the North Pacific or even straight from the Arctic Circle. The jet stream can be traced from Barrow, Alaska to Las Vegas, Nevada.The strong anticyclonic curvature and convergence over the Yukon helped to produce an incredible 1061 mb (31. 33 inches) surface high pressure cell.Polar airmasses have penetrated so deeply in this pattern that Houston had its earliest snowfall ever on Friday. Snow even fell at Galveston, TX, Slidell, La and Galliano, LA, which is about 40 miles south of New Orleans. The snowstorm then hit all the major cities along the east coast on Saturday, from Washington D.C. to Boston. Last night, Las Vegas, Tucson, and every county in southern Texas except Cameron (i.e. Brownsville) were under freeze warnings. Tonight, (Sunday morning) Freeze warnings run from New Orleans to the entire Florida Panhandle, frost advisories are in place for the northern half of the San Joaquin Valley in California, with freeze watches going down to Bakersfield.The next system is already getting started with blizzard warnings active in western Colorado. Another much larger storm will rapidly intensify in California on Monday and has prompted winter storm watches all the way down to southeastern Arizona. This storm will also likely dump at least several feet of snow on the higher mountains in Utah and Colorado and up to around one foot from parts of the central Plains to the western Great Lakes.
In the Pacific, the polar jet stream has amplified enough to get a 948 mb storm to form down to 41N latitude - no pineapple express here.