Thanks to ken Kato for heads up for this event . NAEFS indicating cold anomalies over all USA and Canada
Sub polar Jetstream pattern is meridonal in the Northern hemisphere and has a well defined wave pattern in the sub polar 200hpa stratosphere.
Cold air advecting southward over the USA in the first week of December 2013
Notice also the sub tropical jet converges with the cold sub polar jet across the USA Friday the 5th December 2013
To follow this event maybe try ACCU weather