30
Day

The most prolonged period of below average winter temperatures in several years underway across the Eastern U.S. includes an overachieving winter storm which generated blizzard conditions between the central Plains and mid Mississippi Valley Sunday that later produced greater coverage of impactful snow and ice than models forecast between the Ohio Valley and mid Atlantic region today.  Arctic air expansion in the wake of the winter storm directed the coldest air yet this season throughout the southeastern quadrant of the U.S. certain to produce several consecutive days of subfreezing overnight low temperatures and very cold daytime highs in the 40s-50s from Texas to the Southeast and Florida this week. While these frigid temperatures are in place across the South (20°-25° below average) latest model forecasts direct another impactful winter storm even farther south across much of Texas (including Dallas) midweek, which may also impact the Northeast next weekend (Jan 11-12).  Cold and stormy forecast consensus has longer range model forecasts maintaining well below average temperatures across the majority of the Eastern half of the U.S. through the following week of Jan 12-18. This colder for longer government model shift east of the Rockies is the closest yet to 30-day MWA ensemble forecasts which prolong high latitude blocking and arctic air reinforcement into the following week as well (Jan 19-25), while noticeably colder air also  drains into the West. However, longer range 30-day MWA ensemble forecasts interpret this period of near coast to coast below average temperatures as harbinger of the next milder Eastern pattern shift set to develop during the final week of January, albeit rate and magnitude of warming into early February will likely be limited by increased snowcover east of the Rockies.