The broad storm organizing over the Great Plains may set off some severe weather form East Texas through the Deep South and Mid-Atlantic over the next 48 hours. But the importance of this system lies in its ability to connect with the cold pool building across northern Canada. With a ridge building along the Pacific coastline form Alaska to British Columbia, drainage of the cA values into the USA should get going around and after Thanksgiving.
There are more disturbances in the subtropical jet stream that is setting up from off of Baja California to Texas into Florida, then over the Gulf Stream. As each impulse passes south of the cold dome, parcels of the Arctic regime will head southward. In time, the leading edge of the chilled air mass will reach as far south as Oaxaca State in Mexico. The only areas to escape the temperature drop with be coastal California and the Florida Peninsula. I can see about two rain events from TX/LA into the Eastern Seaboard over the near term and medium range.
And of course…what about snow? This is still not an ideal set-up for synoptic snowfall outside of the Intermountain Region and Ontario/Quebec through the end of the month. Minor snow shower and squall potential may pop up to the lee of the Great Lakes. There may even be a surprise snow episode in the central High Plains.
Cold air may make repeated trips into the lower 48 states through December 7. A large storm coming out of northern Mexico into the Ohio Valley in the second week of next month should set up more rain and perhaps milder temperatures to the right of the Rocky Mountains.