Low water level in a wet pond.

March 2023 – Warm with Much Below Normal Precipitation Across Delaware

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 45.8o F, which is 1.6o F above the 1991-2020 mean value of 44.2o F (Figure 1).  March 2023 was the 30th warmest since observations began in 1895.

March Precipitation

Delaware’s statewide precipitation for March 2023 averaged 1.82 inches, 2.30 inches below the 1991-2020 mean (Figure 2).  This month’s precipitation was the 11th driest since 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly positive across the entire state (Figure 3) with the largest positive departures found in New Castle County.  Precipitation anomalies were consistently negative across the entire state, with most stations seeing rainfall more than two inches below normal for the month (Figure 4).   

National Anomalies

Temperatures were much below normal across the western one-half of the United States, with some negative departures reaching nearly 15o F across the Dakotas (Figure 5).  The Gulf coast states generally saw above normal temperatures during the month (Figure 5).  Precipitation departures were mixed across the country, with the largest positive precipitation anomalies found across California (Figure 6). The 500 hPa height pattern for March shows an extensive jet stream trough over the western two-thirds of the United States contributing to the temperature anomalies across that region (Figure 7).

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March 2022 – Warm and Dry Conditions Continue Across Delaware

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 47.3o F, which is 3.1o F above the 1991-2020 mean value of 44.2o F (Figure 1).  March 2022 was tied with March 1913 as the 15th warmest since observations began in 1895. 

March Precipitation

Delaware’s statewide precipitation for March 2022 averaged 2.97 inches, 1.15 inches below the 1991-2020 mean (Figure 2).  This month’s precipitation was tied with 1982 as the 37th driest March since records began in 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were above normal across the entire state, with many stations seeing positive temperature anomalies of greater than 4o F (Figure 3).  Precipitation was below normal across the entire state, with the largest negative departures found across New Castle County (Figure 4). 

National Anomalies

Temperatures were above normal across the eastern one-third of the United States, and along the Pacific Coast, with some areas seeing positive departures of 3o – 5o F.  The central portions of the country saw below normal temperatures with some negative departures as much as 3o – 5o F scattered throughout the region (Figure 5).  Precipitation anomalies varied greatly across the country (Figure 6), with generally dry conditions across the western one-half of the nation.  Wet conditions were found across the Great Lakes and Mississippi Valley.  The 500 hPa height pattern for March shows a jet stream trough located over northeastern North America and a jet stream ridge over both the eastern and western United States contributing to the temperature anomalies across those regions (Figure 7).

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pink flowers

March 2021 – Very Warm with Near Normal Precipitation Across Delaware

 

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 48.0° F, which is 4.0° F above the 1981-2010 mean value of 44.0° F (Figure 1).  March 2021 was the 12th warmest March since observations began in 1895.

March Precipitation

Delaware’s statewide precipitation for March 2021 averaged 4.35 inches, 0.15 inches above the 1981-2010 mean (Figure 2).  This placed this month’s precipitation total in the “normal” category.  Only isolated areas of snow flurries and snow showers fell during March, with no snowfall accumulation recorded at the Wilmington/New Castle County Airport.  

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly positive at all stations, with the largest positive anomalies toping 3.0° F  at several stations across New Castle County (Figure 3).  Precipitation was generally near normal throughout the State with the largest positive anomalies found across Kent County (Figure 4).

National Anomalies

Temperatures were generally above normal across the eastern two-thirds of the United States, with the largest positive temperature anomalies (greater than  7° F) found across the Dakotas and Minnesota (Figure 5).  Only the western United States saw below normal March temperatures.  Precipitation anomalies varied greatly across the country with particularly heavy precipitation across the central United States.  In general, both the Pacific and Atlantic Coasts saw below normal precipitation during the month (Figure 6).  The 500 hPa height pattern for March shows a strong jet stream ridge across the eastern United States (Figure 7) associated with the high temperatures across the eastern portions of the country.

 

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Warm sun paints sky golden

March 2020 – Very Warm with Below Normal Precipitation

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 49.8o F, which is 5.8o F above the 1981-2010 mean value of 44.0o F (Figure 1).  March 2020 was the 4th warmest since 1895 in Delaware.

March Precipitation

Delaware’s statewide precipitation for March 2020 averaged 3.59 inches, 0.61 inches below the 1981-2010 mean (Figure 2).  This placed the March 2020 precipitation amount in the “normal” category when compared to all years since 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were above normal throughout the State (Figure 3), with most stations more than 4o F above the 30-year mean.  Precipitation was below normal at most locations, with the largest negative anomalies found in southern Sussex County (Figure 4).

National Anomalies

Temperatures were above normal across the eastern two-thirds of the U.S., with departures reaching 7o to 10o F along the Gulf Coast.  Small negative temperature departures were found along the Pacific Coast of the country (Figure 5).    Precipitation varied greatly across the U.S. with extremely wet conditions across the Southwest and dry conditions along the Gulf Coast (Figure 6).  The 500 hPa height pattern for March showed a strong ridge dominating the eastern two-thirds of the country (Figure 7) leading to the warm temperatures across our region.

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Spring 2019 – Warm Temperatures and Near Normal Precipitation Across Delaware

Spring Temperatures

Spring Temperatures Preliminary data indicates that spring temperatures averaged 55.8°F, 2.4°F above the 30-year “normal” of 53.4°F (Figure 1). Spring 2019 is tied with 1945 and 2011 as the 7th warmest since records began in 1895.

Spring Precipitation

Spring Precipitation The statewide mean precipitation of 12.10 inches was 0.4 inches above the 1981-2010 normal of 11.70 inches (Figure 2). This value placed the spring of 2019 in the wettest one-third of years since 1895.

Statewide Spatial Averages

Statewide Spatial Anomalies Data from the Delaware Environmental Observing System (DEOS) show that spring temperature anomalies were above normal across the entire State (Figure 3). Spring precipitation anomalies varied significantly across the state, but were all above normal (Figure 4). Anomalies were greater than three inches at several of the DEOS stations.

National Anomalies

National Anomalies Above normal spring temperatures were found across the southern Atlantic coast of the U.S. from Florida through the Mid-Atlantic Region (Figure 5), while colder than normal temperatures were found across the north-central portions of the country. Precipitation varied greatly across the continental United States, with the Mid-Atlantic Region generally seeing above normal values (Figure 6).

Positive 500 hPa height anomalies were present over the Mid-Atlantic Region during the spring season, indicative of anomalous ridging with enhanced flow from the south and moisture transport into our State (Figure 7). This anomalous flow helped to make the season warmer and wetter than normal.

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March 2019 – Temperature and Precipitation Both Above Normal Across Delaware

 

 

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 42.6°F, which is 1.2°F below the 1981-2010 mean value of 43.8°F (Figure 1). This places March 2019 temperatures in the middle one-third of monthly values since 1895.

March Precipitation

Delaware’s statewide precipitation for March 2019 averaged 3.93 inches, 0.34 inches below the 1981-2010 mean (Figure 2). Snowfall was slightly above normal during the month across northern Delaware with 3.4 inches of snow recorded at the Wilmington – New Castle County Airport (normal is 3.2 inches). Two snowfall events dropped more than an inch of snow across the northern half of the State on March 1st and again on the 3rd.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were below normal across the entire state (Figure 3), while precipitation departures varied depending upon location (Figure 4) with above normal precipitation in the north, and below normal precipitation in the south.

National Anomalies

Most of the United States, except for the southwest, saw negative temperature anomalies during March. Specifically, the Dakotas and Montana saw extreme cold with temperatures up to 10°F below normal for the month (Figure 5). The Great Plains and the interior west were all wetter than normal while the eastern United States generally saw below normal precipitation (Figure 6).
The 500 hPa height pattern for March showed no strong jet stream ridging or troughing over our region (Figure 7).

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Bright yellow flowers contrast a bright blue sky

Near Normal Temperatures and Above Normal Precipitation Characterize the 2018 Spring Season Across Delaware

 

 

Spring Temperatures

Preliminary data indicates that spring temperatures were exactly equal to the 30-year “normal” of 53.4°F (Figure 1). This was the fourth year in a row with spring temperatures at or above the 30-year mean.

Spring Precipitation

The statewide mean precipitation of 14.48 inches was 2.78 inches above the 1981-2010 normal of 11.70 inches, making it the 15th wettest since records began in 1895 (Figure 2).

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that spring temperature anomalies across the State varied dependent upon location and were generally small at all stations (Figure 3). Spring precipitation totals were above normal across most of the State, with the largest positive anomalies found across Sussex County (Figure 4), where some stations recorded spring precipitation amounts more than six inches above average.

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Light snow illuminated by the Sun

Cold Conditions Return to Delaware During March 2018

 

 

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 40.6°F, which is 3.4°F below the 1981-2010 mean value of 44.0°F (Figure 1). March 2018 was 2.3°F colder than March (an unusual occurrence) and was the 40th coolest March since 1895. Much of the mid-Atlantic region of the United States was also colder than normal during the month, especially across portions of Virginia and North Carolina (Figure 2).

March Precipitation

Delaware’s statewide precipitation for March 2018 averaged 3.89 inches, 0.31 inches below the 1981-2010 mean (Figure 3). Even though total precipitation was below normal, much of the precipitation that did fall fell as snow due to the cold March temperatures. During the month 14.2 inches of snow fell at the Wilmington – New Castle County Airport . This was 11 inches above the March average snowfall of 3.2 inches, and the 2nd largest March total since snowfall records began in 1948.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were below normal across the entire State (Figure 4), with the greatest anomalies of over 5°F found across Sussex County. Precipitation departures were just below, or just above normal at all stations (Figure 5), with most stations seeing departures of 1 inch or less.

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Wet pink flowers in green grass

Warm and Moist Conditions Characterize the 2017 Spring Season Across Delaware

 
 

Spring Temperatures

Preliminary data indicates that spring temperatures were above the 30-year “normal”. The statewide mean spring temperature of 55.4°F was 2.0°F above the 1981-2010 mean value of 53.4°F (Figure 1). Spring 2017 was tied with 2002 as the 10th warmest since records began in 1895.

Spring Precipitation

The statewide mean precipitation of 13.00 inches was 1.30 inches above the 1981-2010 normal of 11.70 inches, putting it in the top 25 wettest since records began in 1895 (Figure 2).

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that spring temperatures across the State were above normal at most locations, with the largest positive anomalies found across inland Sussex County (Figure 3).

Spring precipitation totals were quite varied across the State with positive anomalies found across northern Kent and southern New Castle Counties, while significant below normal anomalies were found in portions of Chester County, PA (Figure 4).

 

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Green leaves in bright sunlight

March 2017: Near Normal Temperatures and Precipitation Across Delaware

 

 

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 43.6°F; this was 0.4°F below the 1981-2010 normal of 44.0°F (Figure 1). March 2017 was the first month since May 2016 registering below normal temperatures.

March Precipitation

Delaware’s statewide precipitation for March 2017 averaged 4.43 inches, 0.23 inches above the 1981-2010 mean (Figure 2). March 2017 was the first month since September 2016 with above normal precipitation across the First State. A late season winter-weather event brought up to 4 inches of snow and sleet to northern sections of New Castle County on the 13th and 14th.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) shows that temperatures varied across the State during the month, with most stations recording below normal mean monthly values (Figure 3). Total liquid precipitation was near normal across most of Delaware, with the driest conditions found across Chester County Pennsylvania (Figure 4).

 

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