Preliminary data indicates that the statewide average temperature in July was 79.4°F, which is 2.8°F above the 1981-2010 mean value of 76.6°F (Figure 1). This places July 2019 as the 6th warmest since records began in 1895.
Delaware’s statewide precipitation for July 2019 averaged 3.79 inches, 0.35 inches below the 1981-2010 mean (Figure 2). Delaware’s July precipitation was in the middle 0ne-third of values for the last 125 years, putting it into the “normal” range for this month.
Statewide Spatial Anomalies
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were above normal throughout the State (Figure 3), with many stations seeing positive anomalies greater than 2.0°F. There was a mixture of positive and negative precipitation departures observed across the State (Figure 4). In general, northern New Castle County had greater than normal precipitation, while Kent and Sussex Counties saw below normal precipitation amounts during the month.
The northeast quarter of the United States experienced above normal temperatures during July, with mixed temperature anomalies found throughout the rest of the country (Figure 5). Precipitation anomalies across the U.S. varied greatly, with above normal precipitation falling across the northern Great Plains, the southern Mississippi Valley and parts of the mid-Atlantic (Figure 6). In general, the southwest United States and California were dryer than normal. The 500 hPa height pattern for July showed weak anomalous ridging over the northeast portion of the Country (Figure 7), bringing the warm temperatures to that region.