Preliminary data indicates that the statewide average temperature in April was 53.8° F, which is 0.6° F below the 1991-2020 mean value of 54.4° F (Figure 1). Even with temperatures cooler than the 1991-2020 mean value, April 2022 still saw temperatures in the top one-third of all years since 1895.
Delaware’s statewide precipitation for April 2022 averaged 3.98 inches, 0.50 inches above the 1991-2020 mean (Figure 2). This month’s precipitation total was in the top one-third of all years since records began in 1895.
Statewide Spatial Anomalies
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were below normal across the entire state, with some stations seeing negative temperature anomalies of greater than 2° F (Figure 3). Precipitation was above normal across the northern two thirds of the state, with the largest positive departures found across New Castle County (Figure 4).
Temperatures were below normal across most of the northern tier of the United States, with some areas seeing negative departures of 7° – 10° F. The southwest portion of the country saw above normal temperatures with some positive departures as much as 5° – 7° F scattered throughout the region (Figure 5). Precipitation anomalies varied greatly across the country (Figure 6), with very dry conditions across the southwestern portion of the nation. Wet conditions were found scattered throughout the country with very high precipitation amounts found across North Dakota and parts of Minnesota. The 500 hPa height pattern for April shows a jet stream trough located over much of northern North America and a jet stream ridge over both the southern Atlantic and Pacific coasts, contributing to the temperature anomalies across those regions (Figure 7).