The teleconnections are aligning in a manner that favors a colder than average period of weather by late-October standards. Note the PNA trend positive while the EPO heads negative. The AO and NAO also follow suit.
The sum of all of the above should feature a predominant western ridge for late month with a persistent eastern trough- at times deeper than others.
Add in the fact that the MJO is anticipated to swing into Phase 2 and this further serves to increase confidence in the colder shift.
The models are focusing in on the colder close to the month and though specifics will continue to vary from run-to-run, the primary message that we want to convey is to expect a colder than average 2nd half of the month with an active storm track. As pops of more “winter-like” air get involved behind one or two of the late month storms, pre-Halloween flakes may fly across a portion of the Ohio Valley.
Given the pattern progression and anticipated teleconnection states, we think it’s wise to ensure the kiddos have a warm Halloween costume this year!