Data Date: April

April 2023 – Very Warm with Above Normal Precipitation Across Delaware

Posted on | by Dan Leathers

April Temperatures

Preliminary data indicates that the statewide average temperature in April was 58.8o F, which is 4.4o F above the 1991-2020 mean value of 54.4o F (Figure 1).  April 2023 was the 2nd warmest since observations began in 1895.

April Precipitation

Delaware’s statewide precipitation for April 2023 averaged 5.65 inches, 2.17 inches above the 1991-2020 mean of 3.48 inches (Figure 2).  This month’s precipitation was tied with 1928 as the 7th wettest since 1895.  Interestingly, most of the April precipitation fell during the final three days of the month. 

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 many locations seeing anomalies of nearly 5o F.  Precipitation anomalies were consistently positive across the entire state, with many stations recording departures of more than four inches, especially in Kent County (Figure 4).   

National Anomalies

Temperatures were generally above normal across the northeastern United States (Figure 5), while the north-central and northwestern portions of the country saw below normal temperatures (Figure 5).  Precipitation departures were mixed across the country, with the largest positive precipitation anomalies found along the Atlantic and Gulf Coast regions (Figure 6). The 500 hPa height pattern for April shows a weak jet stream trough covering most of the western two-thirds of the United States, while much of the eastern one-third of the country was covered by a jet stream ridge, contributing to the temperature anomalies found across these regions (Figure 7).

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April 2022 – Cool and Wet Conditions Prevail Across Delaware

Posted on | by Dan Leathers

April Temperatures

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.  

April Precipitation

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).  

National Anomalies

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).

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Barley/Wheat Field under the Sun

April 2021 – Warm with Below Normal Precipitation Across Delaware

Posted on | by Dan Leathers

April Temperatures

Preliminary data indicates that the statewide average temperature in April was 55.7o F, which is 2.2o F above the 1981-2010 mean value of 53.5o F (Figure 1).  April 2021 was the 13th warmest April since observations began in 1895.

April Precipitation

Delaware’s statewide precipitation for April 2021 averaged 2.25 inches, 1.39 inches below the 1981-2010 mean (Figure 2).  This placed this month’s precipitation total in the bottom one-third of all years since 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were positive at most stations, with the largest positive anomalies found across New Castle County (Figure 3).  Precipitation was below normal at nearly all stations throughout the State with the largest negative anomalies found across eastern Kent County (Figure 4).

National Anomalies

Temperatures were generally below normal across the central portion  of the United States, and warmer than normal along both the Pacific and north-Atlantic coasts (Figure 5).  Precipitation anomalies varied greatly across the country with particularly dry conditions across most of the western half of the United States.  The Gulf Coast, from Louisiana east to Florida, saw much above normal precipitation (Figure 6).  The 500 hPa height pattern for April shows a jet stream ridge across the Pacific Coast and a weak jet stream trough across the central and eastern portions of the country (Figure 7), contributing to the overall temperature pattern.

 

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Rain on window

April 2020 – Cool and Moist Across Delaware

Posted on | by Dan Leathers

 

April Temperatures

Preliminary data indicates that the statewide average temperature in April was 52.4o F, which is 1.1o F below the 1981-2010 mean value of 53.5o F (Figure 1).  April 2020 was the first month with below normal temperatures since November 2019.

April Precipitation

Delaware’s statewide precipitation for April 2020 averaged 4.09 inches, 0.45 inches above the 1981-2010 mean (Figure 2).  This placed the April 2020 precipitation amount in the top one-third of all years since 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were below normal throughout the State (Figure 3), with most stations between 2o and  4o F below the 30-year mean.  Precipitation was above normal at all locations, with the largest positive anomalies of between one and two inches across Kent and New Castle Counties (Figure 4).

National Anomalies

Temperatures were below normal across the eastern two-thirds of the U.S., except near the Gulf Coast states. Departures were generally between  1o to 5o F below normal in this area.  Positive temperature anomalies were found across much of the western and southwestern portions of the United States (Figure 5).  Precipitation was generally above normal in the eastern one-third of the United States and below normal across the west, except for large positive anomalies across southern California (Figure 6).  The 500 hPa height pattern for April showed a strong trough dominating the eastern two-thirds of the country (Figure 7) leading to the cooler temperatures across our region.

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A New Statewide 24-Hour Precipitation Record for Delaware!

Posted on | by Dan Leathers

It’s been awhile, but it’s now official. Delaware has a new 24 hour precipitation record. Also, this is the first state climate record in Delaware using one of our DEOS stations! We hope you’ll take a look at the report to find out more.

Rainfall over a 24-hour period in Delaware has broken the state’s record. Between September 28–29, 2016, near Harbeson,…

Posted by NOAA National Centers for Environmental Information on Tuesday, April 28, 2020

Spring 2019 – Warm Temperatures and Near Normal Precipitation Across Delaware

Posted on | by Dan Leathers

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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April 2019 – Near Record Warm Temperatures and Near Normal Precipitation Across Delaware

Posted on | by Dan Leathers

April Temperatures

Preliminary data indicates that the statewide average temperature in April was 58.0°F, which is 4.5°F above the 1981-2010 mean value of 53.5°F (Figure 1). This places April 2019 as the 2nd warmest since records began in 1895.

April Precipitation

Delaware’s statewide precipitation for April 2019 averaged 3.40 inches, 0.28 inches below the 1981-2010 mean (Figure 2). Delaware’s April precipitation was in the middle one-third of values for the last 125 years.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly above normal across the entire state (Figure 3), with many stations seeing anomalies of greater than 4.0°F. Precipitation departures varied depending upon location (Figure 4) with below normal precipitation in the north, and above normal precipitation values across the south.

National Anomalies

Most of the United States saw positive temperature anomalies during April, with the Mid-Atlantic Region and portions of California seeing the largest temperature departures (Figure 5). Much of the country saw above normal precipitation, except for the Great Plains, California and the Southwest (Figure 6).
The 500 hPa height pattern for April showed anomalous ridging of the jet stream over our region leading to enhanced southerly flow and higher than normal temperatures (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

Posted on | by Dan Leathers

 

 

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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Dandelions in bright green grass

Delaware Temperatures Continue Below Normal During April 2018

Posted on | by Dan Leathers

 

 

 
 

 

 

 

 

April Temperatures

Preliminary data indicates that the statewide average temperature in April was 51.1°F, which is 2.4°F below the 1981-2010 mean value of 53.5°F (Figure 1). April 2018 was the 39th coolest April since 1895 and was 8.4°F below temperatures during April 2017. The cool conditions across Delaware were consistent with temperature anomalies across the eastern two-thirds of the United States where temperatures were similarly below normal (Figure 2).

April Precipitation

Delaware’s statewide precipitation for April 2018 averaged 3.41 inches, 0.23 inches below the 1981-2010 mean (Figure 3). Even though precipitation has been slightly below normal the last two months, the year-to-date precipitation for 2018 is running in the top 33% of years since 1895.

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 anomalies as much as 4o F below the average at some stations. Precipitation was generally below normal across the State except for a few stations in central Sussex and southern Kent Counties (Figure 5). Most stations saw precipitation departures of one inch or less.

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Wet pink flowers in green grass

Warm and Moist Conditions Characterize the 2017 Spring Season Across Delaware

Posted on | by Dan Leathers

 
 

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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