10/09/2022, 11:41 am EDT

Clearway Energy September 2022 Wind and Solar Verification Report

Discussion: The September 2022 climate across the U.S. was characterized by anomalous warmth dominating the West alongside a stronger than normal Southwest wet monsoon while the East-central/Mid-south U.S. observed very dry conditions. The zonal wind anomalies observed in September were lighter than normal across the Southwest U.S. and Continental Divide region while slightly above normal in Pennsylvania (Fig. 1). In the East, meridional wind was lighter than normal (Fig. 2). There was an area of stronger than normal meridional wind across Southern California. The September forecast anticipated a much stronger zonal wind across the Southeast U.S. (Fig. 3). That result is surprising as the projected upper air pattern (high pressure West/low pressure Northeast) verified. The forecast indicated above normal west-to-east flow south of the Northeast low-pressure area, but observation reveal the wind was lighter than normal (from the west). The meridional wind anomaly forecast indicated light wind across the Central U.S. (Fig. 4). However, observations reveal wind speeds in the north and/or south direction were near normal during the late warm season. Fig. 1-2: September 2022 observed zonal and meridional wind anomalies. Fig. 3-4: Original Climate Impact Company zonal and meridional wind anomaly forecast for September 2022. In September 2022, the above normal strength of the wet Southwest U.S. Monsoon was dominant. Heavy convection leads to well above normal moisture at 850 MB (Fig. 5) extending westward to California (at times). In opposition to that pattern was generally clear skies across the expanding drought zone in the Mid-south U.S. The high cloud regime (at 300 MB) also followed the low cloud pattern closely (Fig. 6). The September forecast completely understood the expanding dryness and drought risk to the Central/Mid-south U.S. (Fig. 7-8). However, the low specific humidity (SH) forecast at low and high levels of the atmosphere in that zone were too strong due to the under forecast SH in the Southwest States. Fig. 5-6: September 2022 observed 850 and 300 MB specific humidity anomalies. Fig. 7-8: Original Climate Impact Company 850 and 300 MB specific humidity anomaly forecast for September 2022.