November 2020 – Exceptionally Warm and Wet Across Delaware

November Temperatures

Preliminary data indicates that the statewide average temperature in November was 52.1^o F, which is 4.5^o F above the 1981-2010 mean value of 47.6^o F (Figure 1).  November 2020 was the 2^nd  warmest November since observations began in 1895.  Only November of 1985 has been warmer.

November Precipitation

Delaware’s statewide precipitation for November 2020 averaged 5.77 inches, 2.37 inches above the 1981-2010 mean (Figure 2).  This placed this month’s precipitation total as the 8^th highest of all months since 1895. 

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were positive at all stations, with the largest anomalies found across Kent and New Castle Counties reaching to approximately 6^o F at some stations (Figure 3).  Precipitation was above normal throughout the State, with departures of greater than four inches common across many areas (Figure 4). 

National Anomalies

Temperatures were above normal across nearly the entire United States, with the largest temperature anomalies (5^o F – 10^o F) found across the north-central portion of the country (Figure 5).  Precipitation anomalies varied greatly across the country with particularly heavy rainfall along the Atlantic coast from Florida to Delaware (Figure 6).  The 500 hPa height pattern for November shows a jet stream ridge covering the eastern two-thirds of the United States (Figure 7).  The placement of the jet stream north of its normal position is responsible for the warm temperatures seen across the country. 

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