Long range forecasts are particularly unreliable lately as a very strong jetstream persists over much of the Pacific and western North America. What is clear though is that increasingly colder artic air is piling up over Alaska and western Canada and during the week after next. Some of this wintery air will make it into the lower 48; most likely over the northern tier states in the east and over much of the inter-mountain west and the Pacific coast as far south as southern California. The SE and gulf coast states can expect average to above average temperatures to continue.
This week will see the battle between winter and warmth fought out mainly over the west; particularly the Pacific NW where temperatures will be below to well below average and significant mountain snow accumulations are expected for the early part of the week but conditions will briefly moderate after Tuesday. Much of the east will be slightly to rather warmer than average to start.. A strong frontal system will develop over central TX and link up with a weak disturbance over the Ohio Valley late monday as some subtropical pacific air crosses the southern Rockies . This frontal zone will bring some rain to much of the SE and east coast as it gradually moves east thru the week. Behind the front conditions will cool over the northern tier of states; as far as lake Superior by Tuesday and cooling will spread into New England on Wednesday. Cold air will deepen especially over the upper midwest thru the week and this deeper colder air will spread into New England by Friday. Another shot of artic air will plunge back into the west next weekend bringing blizzard conditions to the northern Rockies on Saturday. Meanwhile most of the SE and gulf coast states can expect a period of generally mild clear weather behind the front starting Thursday and continuing thru the weekend.