Important Tropical Events Could Affect U.S. In Early October
09/23/2021, 10:07 am EDTRegional SSTA Tracking
09/28/2021, 1:53 pm EDT
Fig. 1: U.S. population weight CDD anomalies for each month of the 2021 warm season (includes September and October projection).
Summer 2021 review: U.S. population weight cooling degree day anomalies for each month of the 2021 warm season indicate a highly variable pattern featuring two excessive warm spikes in June and August surrounding a moderate warm anomaly for July (Fig. 1). The season started near normal (APR/MAY) followed by excessive early season heat in June. Nationally, July was very wet during mid-summer suppressing the July excessive heat. The August warm anomaly was the strongest of the season. Note the character of the 2021 warm season featured two hot monthly spikes compared with steadily warmer anomalous months from June to September of the past two summer seasons.
Fig. 2: U.S. gas population weight HDD anomalies for each month of the 2021-22 cold season.
Winter 2021-22 forecast: The U.S. gas population weight HDD forecast for the 2021-22 cold season is preliminary (Fig. 2). The extent of snow cover will determine the more likely anomalous solution vs. the initial projection. The current projection indicates below normal national heating demand to start the 2021-22 cold season. December and January are closer to the 30-year normal but still warmer-than-normal. However, DEC/JAN are projected considerably colder than each of the past 3 years. Late winter is currently projected moderately warmer than normal.