Preliminary data indicates that the statewide average temperature in September was 69.6o F, which is 0.5o F above the 1991-2020 mean value of 69.1o F (Figure 1). September 2022 was in the top one-third of all September temperatures since observations began in 1895.
Delaware’s statewide precipitation for September 2022 averaged 3.50 inches, 0.72 inches below the 1991-2020 mean (Figure 2). This month’s precipitation value placed it in the normal category when compared to September values since 1895.
Statewide Spatial Anomalies
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were varied across the state (Figure 3) and generally small. Precipitation observations were below normal at all but two stations across the State, with some negative precipitation anomalies topping two inches (Figure 4).
Temperatures were above normal across most of the conterminous United States west of the Mississippi River, and across much of the mid-Atlantic. Only the Appalachians and parts of the southeast U.S. saw temperatures below normal. In general, dry conditions prevailed across much of the eastern half of the United States, except for northern Pennsylvania, New York, and New England. The 500 hPa height pattern for September shows a jet stream ridge over the western United States contributing to the positive temperature anomalies across that region (Figure 7).