Could be a warm up second half of month, but looks like SSW will at least throw my timing off.
High Latitude Blocking Likely to Delay February Forecast Warm up
A major premise of the seasonal forecast was that while the polar vortex would be prone to assaults early on in the season, it would ultimately recover, however, the major Sudden Stratospheric Warming event that occurred in early January proved that particular supposition incorrect.
Note how diffuse and nearly indiscernible the polar vortex remains at present, as the polar stratosphere remains infiltrated with warmth.
Clearly the polar domain is still reeling from last months Sudden Stratospheric Warming, which means that, an end to the current high latitude blocking regime is not imminent. While this is in conflict with the timing of the progression laid out in the Winter Outlook, the current data is indisputable and overwhelming. However, as was the case with the development of the RNA, it may be a case of delayed, but not denied.
Note the recovery to at least near neutral with respect to the polar fields, as forecasted by the EPS:
Recovery of Polar domain and consolidation of polar vortex forecast later in February.
Likewise, a realignment of the Pacific is also expected to take place toward mid month, as lower heights work in tandem with RNA to induce an active Pacific jet.
Active Pacific Jet Expected for Especially Second Half of February
This evolution is well supported by the European weekly product.
Depicted below is the major negative NAO and EPO blocks that are expected to persist throughout the early portion of the month:
Note by mid month, the NAO block has weakened, and the EPO block as retrograded towards a more classic la nina position, in the vicinity of the Aleutians. The latter of which continues lower heights in the west.
Finally, by the final week of the month, there is a vortex in the vicinity of Alaska, which would flood the CONUS with milder Pacific air, and at least theoretically, make sustaining any residual high latitude blocking more difficult.
This is congruent with a the longer range forecast for a more consolidated polar vortex, which is more fixed near the pole.
In summary, while the month of February is certain to feature more high latitude blocking than forecast due in large part to the early January Sudden Stratospheric Warming, there remains ample opportunity for the original forecast monthly departure of +2 to +4F to verify due to anticipated second half warming. Regardless, the month does not appear to be void of opportunities for winter storms, nor was it ever anticipated to.