30
Day

The warmest temperatures of winter observed from coast to coast multiple days last week ended this past weekend with a final blast of extreme arctic air surging deep into the Midwest and East (several degrees below average even by midwinter standards), and noticeably cooler unsettled conditions spreading out of the West into the Plains.  Moderation is slow across the East maintaining one final day of several degree below average temperatures Monday, before onset of faster warming Tuesday which model consensus peaks 10°-15° above average midweek ahead of a large and powerful spring storm lifting northeastward out of the Southwest. However, once the potent midweek storm producing widespread soaking rainfall east of the Rockies (with some snow along its northern periphery) exits into southeast Canada noticeably colder air is certain to drain into the eastern half of the U.S. before the coming workweek is over. Latest modeling is colder across the Plains and Midwest Wednesday and Thursday (seasonal), and slightly-moderately below average in the Northeast for a longer 3-day period Friday through next weekend (Mar 7-9). The majority of the West shifts even colder for longer this week (~10° below average).  Unlike winter no areas are likely to experience extreme magnitude cold temperatures, but prolonged pattern repetition also precludes repeat of the type of widespread anomalous warmth observed across the entire U.S. the final week of Februrary. The West and Northeast appear on track to be the focus of most frequent moderate cold air outbreaks during the next 2-3 weeks, but longer range 30-day MWA ensemble forecasts valid the final week of March are latching onto significantly greater expansion of seasonably cold air in all but the Deep South. Whether or not late March shifts cold across most of the U.S. the initial half of spring 2025 is of increased confidence to verify several degrees colder than above average temperatures observed across the Eastern half of the U.S. both March and April last year.