Highlight: A weather within climate comment.
Fig. 1-3: North America temperature anomalies for meteorological winter 2021-22 so far (upper) and the December 2021 plus Jan. 1 to Feb. 8, 2022 temperature anomaly pattern(s).
Weather within climate: So far, meteorological winter 2021-22 is warmer than normal (Fig. 1). The core of the warm anomaly is across the southern Great Plains. Only the northern portion of the Upper Midwest is colder than normal. Of course, Canada has observed a frigid winter so far. Interestingly, the average temperature departure from normal since Dec. 1, 2021 does not identify the character of the winter pattern through early February. In December, an intense upper trough dropped anchor over Western Canada causing frigid weather there but south of the attendant jet stream axis the U.S. observed their 2nd warmest December of the past 20 years (Fig. 2). In January, the polar vortex pattern shifted east to Hudson Bay causing frequent cold outbreaks across the eastern half of the U.S. (Fig. 3). Seasonal forecasts are important. But the weather within climate is most impactful on the public and industry.
Latest 12Z GFS: Staying in-step with the “weather within climate” theme, the cold polar vortex of mid-winter is retreating northward slowly in the medium-range and taking the deep cold along (Fig. 4-5).
Fig. 4-5: The midday 12Z GFS North America temperature anomalies.
|Dates||HDD Forecast||12-Hr Change||24 Hours Ago||10-Year NML||30-Year NML|
Table 1: Indicated is the 12Z GFS projected gas population weight HDD for the U.S. compared to 12 and 24 hours ago through late February.