This week’s pattern featuring resurgent mild weather across central & eastern regions and a stormy disposition along the west coast will degrade by day 7 as upper troughiness eases upstream in the Pacific.
This is characterized by the rising PNA which signals an evolving ridge and a warmer-than-average temp profile developing for the west through at least a portion of next week and perhaps beyond.
Downstream a trough should dig into SK, MB & ON with associated unsettled and cooler conditions following another notable warm spell through the mid-range. This cooldown could face resistance into the Atlantic Provinces and instead discharge S/SE through the USA.
Pacific North American (PNA) pattern:
A rundown of temperature departures through the medium and extended range displaying this prospective shift.
12z EPS 2m temp anomalies, days 0-5:
12z GEFS 2m temp anomalies, days 10-15:
12z NAEFS temp probabilities, days 8-14:
Also the ‘big 3’ global deterministic models are in general agreement in their respective takes on the mid-term layout, albeit with some differences in amplitude.
12z ECMWF / GFS / CMC 500mb height anomalies, days 8-10:
A fresh run of the Euro weeklies will be useful to work out the long range.