Impressive Cold Pattern Change in U.S. Based on 12Z GFS

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Fig. 1-2: The 12Z GFS medium-range temperature anomaly forecast.

Discussion: The GFS continues to trend colder in the medium range forecast for the U.S. valid the last third of November (Fig. 1-2). The colder support from climate signals is becoming evident for central North America via negative phase of the West and East Pacific oscillations. However, other climate signals supporting the cold remain weak. Other forecast models are trending colder but nowhere near as cold as the GFS. Snowfall in the Northern U.S. is likely in this pattern favoring the northern Great Plains, Midwest States, and Appalachian States. The U.S. gas population weight HDD forecast surges to 190 HDD for the last week of November (Table 1).

DatesHDD Forecast12-Hr Change24-Hr Change30-Year NML10-Year NML
Nov. 10-16


Nov. 17-23


Nov. 24-30



Table 1: The 12Z GFS U.S. gas population weight HDD forecast compared to 12 and 24 hours ago.