Negative phase of the Pacific North America (-PNA) index is intact causing a cold and snowy Northwest U.S. regime widening due to the expansiveness of the snowfall (Fig. 1). Meanwhile record warmth across the East is about to diminish as a negative phase of the North Atlantic oscillation (-NAO) unfolds initially bringing a possible record cold and snowy end to winter in Europe followed by a colder regime in the East in the medium-range (Fig. 2). The –PNA/-NAO pattern combine to push most of the U.S. to colder than normal in 15 days (Fig. 3-4).
Fig. 1-2: 14-day PNA and NAO forecast by NOAA.
Fig. 3: Temperature anomaly forecast in 360 hours by the GFS ENS indicates all but the Southwest colder than normal.
Fig. 4: Temperature anomaly forecast in 360 hours by the ECM ENS indicates all of the U.S. is colder than normal.