Still to early to tell about the very end of the month, but this post by Griteater makes a good point about opposing forces, at least at the end of the month.
Posted 1 hour ago
A few thoughts on the pattern ahead...
The jet in the E Pac is going to collapse over the next 5-6 days. Meanwhile, there will be a new jet extension in the W Pac that kicks out off E Asia beginning on day 3 (Jan 14).
As we go out in time into the last 10 days of Jan, there are going to be competing forces that will likely play a role in determining how much this next jet extension pushes east.
The MJO tropical forcing is likely to become active in the Indian Ocean (Phase 2-3) which is a setup that favors limited jet extension, leading to a -PNA pattern.
In contrast, the developing height anomaly pattern over Asia of ridge in west & central Asia and trough in E Asia is one that will favor surface high pressure systems dropping down into E Asia, which typically leads to momentum being added into the Pac Jet as low pressure systems exit E Asia and head toward the Aleutian Islands, leading to a -EPO and/or +PNA pattern.
I'd say I'm 50/50 on it at the moment in terms of how this will lean for the last week of Jan into the beginning of Feb.