Data Date: February

Bright warm sunlight illuminates plants

February 2017: Record Warmth and Much Below Normal Precipitation for Delaware

Posted on | by Dan Leathers
 
 

 

February Temperatures

Preliminary data indicates that the statewide average temperature in February was 44.1°F; this was 7.6°F above the 1981-2010 normal of 36.5°F (Figure 1). February 2017 was the warmest February since records began in 1895. As an example of the warmth Porter Reservoir, in northern Delaware, set new high temperature records on four days during the month. February 2017 was also the 9th month in a row with above normal temperatures across the First State.

February Precipitation

Delaware’s statewide precipitation for February 2017 averaged 1.29 inches, 1.62 inches below the 1981-2010 mean (Figure 2). Very little snow fell across the State in February, as in most cases temperatures were too warm to support frozen precipitation. Between one and three inches of snow fell across New Castle County on February 9th, the only measureable snow during the month.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) shows that temperatures were above normal across the entire State, with departures reaching over 9.0°F in many locations (Figure 3). Total liquid precipitation was significantly below normal across the State, with most departures between one and two inches (Figure 4).

 

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Rain drops fall upon a wooden surface

Warm and Moist Conditions Return to Delaware During February 2016

Posted on | by Dan Leathers

 

 

February Temperatures

Preliminary data indicates that the statewide average temperature in February was 38.6°F; this was 2.1°F above the 1981-2010 normal of 36.5°F (Figure 1). February 2016 was 12.5°F warmer than February 2015, which was one of the coldest ever recorded across the First State.

February Precipitation

Delaware’s statewide precipitation for February 2016 averaged 4.05 inches, 1.14 inches above the 1981-2010 mean (Figure 2). Snowfall across the State was modest during February, with 5.8 inches falling at the Wilmington/New Castle County Airport.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) shows that temperatures were above normal across a majority of the State, with the largest positive anomalies across northern Sussex County, DE and Chester County, PA (Figure 3). Total liquid precipitation was generally above normal across the entire State during February (Figure 4).

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Raindrops on glass

Very Warm and Moist Conditions Characterize the 2015-2016 Winter Season Across Delaware

Posted on | by Dan Leathers
 
 

 

Winter Temperatures

Preliminary data indicates that winter temperatures were far above the 30-year “normal” during the winter season. The statewide mean winter temperature of 41.1°F was 4.8°F above the 1981-2010 mean value of 36.3°F (Figure 1). This made winter 2015-2016 the 4th warmest since records began in 1895.

Witer Precipitation

The statewide mean precipitation of 11.47 inches was 1.71 inches above the 1981-2010 normal of 9.76 inches, and was the 3rd year in a row with above normal winter precipitation (Figure 2).

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that winter temperatures across the entire State were above normal, with the largest anomalies found in northern Sussex and northern New Castle counties in Delaware and in Chester County, PA (Figure 3).

Winter precipitation varied significantly across the State depending upon location. In general, the heaviest precipitation fell across interior Sussex County, DE (Figure 4). At the New Castle County Airport, 22.7 inches of snow fell during the December through February winter season, a value slightly above the 1981-2010 mean.

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Drops of water on bright green grass

Temperature and Precipitation Both Above Normal Across Delaware During 2015

Posted on | by Dan Leathers
 
 
 

Annual Temperatures

Statewide mean annual temperature in 2015 was 56.4°F according to preliminary data from the National Climatic Data Center (NCDC). This was 1.0°F above the 1981-2010 normal of 55.4°F (Figure 1) and was the 11th warmest year in Delaware since 1895.

Monthly temperatures varied greatly throughout the year (Figure 2). The first three months of 2015 saw much below normal temperatures, including the 6th coldest February since 1895. The last nine months of the year saw above normal temperatures, except for October, which was slightly below normal. Tremendous warmth ended the year with December temperatures averaging 12.4°F above the 1981-2010 mean. December 2015 was the warmest December on record, smashing the old record by 6.1°F.

Annual Precipitation

Statewide precipitation in 2015 averaged 46.37 inches, 2.04 inches above the 1981-2010 mean of 44.33 inches (Figure 3).

Monthly precipitation anomalies varied between positive and negative throughout the year, with seven months of below normal and five months of above normal precipitation (Figure 4). June saw the largest precipitation anomaly of 5.30 inches above the 30-year normal, helping to push the annual value above the long-term mean.

Statewide Spatial Averages

According to data from the Delaware Environmental Observing System (DEOS; deos.udel.edu), mean annual temperature anomalies varied across Delaware (Figure 5). Northern New Castle County, much of Sussex County, southern Kent County and Chester County, PA all experienced above normal temperatures for the year. Coastal Sussex County and western portions of News Castle and Kent counties saw below normal mean annual temperatures.

Precipitation across the region varied substantially in 2015, ranging from just under 40 inches to greater than 50 inches at several locations across the State (Figure 6).

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Barn in Snow

Cold and Snowy Conditions Dominate Delaware’s 2014-15 Winter Season

Posted on | by Dan Leathers
de_statewideWinterTemp-1896-2015
Figure 1. Delaware statewide mean winter temperature (°F) 1895-1896 through 2014-15.

 
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Figure 2. Delaware statewide winter precipitation (inches) 1895-1896 through 2014-15.

 

Winter Temperatures

Preliminary data indicates that Delaware’s winter (December, January and February) temperature was below the 1981-2010 normal for the second year in a row. The Statewide mean winter temperature of 33.1°F was 3.2°F below the 30-year normal of 36.3°F. The 2014-15 winter season was the 30th coolest since records began in 1895 (Figure 1).

Winter Precipitation

Cold temperatures were accompanied by above normal precipitation across the state during the winter season. The statewide mean precipitation of 11.05” was 1.29” above the 1981-2010 normal of 9.76”, and was the second winter in a row with above normal values, and the 34th wettest winter since records began in 1895 (Figure 2).

Statewide Spatial Averages

Mean winter temperatures across the state were cold throughout, with temperatures ranging from 2.5°F to as much as 6.5°F below the 30-year mean (Figure 3). Precipitation across the State was highest across Sussex County, with values of over 12 inches in several locations (Figure 4). Winter precipitation values were lower over New Castle County, DE and Chester County, PA, with values generally less than 10 inches.

The colder than normal temperatures, combined with ample precipitation resulted in snowfall totals that were generally above normal across most of the State. Fifteen snowfall events dropped measurable snow on the First State during the winter season. Snowfall during the months of November through March (Delaware’s typical snowfall season) was greater than 20 inches across most of northern New Castle County, DE and Chester County, PA (Figure 5). Snowfall across Kent and Sussex Counties generally ranged from 13 to nearly 20 inches.

Winter 2014-15 average temperature departures from the 1981-2010 mean based upon DEOS station data.
Figure 3. Winter 2014-15 average temperature departures from the 1981-2010 mean based upon DEOS station data.

 
Winter 2014-15 precipitation based upon DEOS station data.
Figure 4. Winter 2014-15 total precipitation based upon DEOS station data.

 
Winter 2014-15 snowfall totals based upon DEOS station data.
Figure 5. Winter (November through March) 2014-15 snowfall totals based upon DEOS station data.
Snow in Woods

Extreme Cold and Below Normal Precipitation Impact Delaware During February 2015

Posted on | by Dan Leathers
Posted on Thu 03/19/15 , Updated 06/04/15

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Figure 1. Delaware statewide mean February temperature (°F) 1895-2015.

 
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Figure 2. Delaware statewide mean February precipitation (inches) 1895-2015.

 

February Temperatures

Preliminary data indicates that the statewide average temperature in February was 26.4°F, 10.1°F below the 1981-2010 normal of 36.5°F (Figure 1). Delaware’s February 2015 temperatures were the coldest since February 1979 and the 7th coldest since records began in 1895.

February Precipitation

Delaware’s preliminary statewide precipitation total for February 2015 averaged 2.37 inches, 0.54 inches below the 1981-2010 mean (Figure 2). Several snowfall events dropped approximately 10 inches of snow across most of Delaware over the course of the month (Figure 3). Notable snowfalls occurred in southern portions of the state on February 17th and 26th, while northern portions of the state had significant snowfall on February 21st.

Statewide Spatial Averages

All stations across the Delaware Environmental Observing System (DEOS) network experienced much lower than normal temperatures during February 2015 (Figure 4). Mean monthly temperatures were generally 9°F to 13°F below normal across the entire State.

All DEOS stations across Delaware saw below normal precipitation totals, with totals for the month ranging from nearly 3 inches in southern Delaware to between 1 and 2 inches across the northern portions of the State (Figure 5).

February 2015 snowfall totals based upon DEOS station data.
Figure 3. February 2015 snowfall totals based upon DEOS station data.

 
February 2015 average temperature anomalies from the 1981-2010 mean based upon DEOS station data.
Figure 4. February 2015 average temperature anomalies from the 1981-2010 mean based upon DEOS station data.

 
February 2015 total precipitation based upon DEOS station data.
Figure 5. February 2015 total precipitation based upon DEOS station data.
Snow on Road

A Wintery Week in Delaware

Posted on | by Dan Leathers

Posted on Thu 02/26/15

Residents will long remember the week of February 15th through February 21, 2015 as a true taste of winter across Delaware.

Cold Air Outbreaks

During the week there were two separate outbreaks of brutally cold air accompanied by strong winds. These outbreaks led to new record low temperatures in some portions of the State, and dangerous wind chill values.

Min Wind Chill Feb. 15, 2015
Figure 1. Minimum wind chill values for February 15th, 2015 based upon DEOS station observations.

 

Min Wind Chill Feb. 15, 2015

Figure 2. Peak wind gusts for February 14th, 2015 based upon DEOS station observations.

Min Temperature Feb. 16, 2015

Figure 3. Minimum temperature for February 16th, 2015 based upon DEOS station observations.

The first cold outbreak followed a cold frontal passage on the evening of February 14th. The cold front ushered in extremely cold air and high winds across the State during the early morning hours of Sunday February 15th. Wind chill readings during the morning of the 15th were well below 0°F across the entire state, with values ranging from -24°F in Chester County, PA to -3.2°F along the Atlantic Coast of Delaware (Figure 1). Winds gusted to over 40 mph in many locations, contributing to the extreme wind chill values (Figure 2). As winds decreased during the early morning hours of Monday February 16th, temperatures were able to drop to record or near record levels at many locations across the State (Figure 3).

Min Temperature Feb. 20, 2015

Figure 4. Minimum temperature for February 20th, 2015 based upon DEOS station observations.

Min Temperature Feb 21, 2015

Figure 5. Minimum temperature for February 21st, 2015 based upon DEOS station observations.

A second cold front moved through the State during the evening hours of Wednesday February 18th. This push of frigid air, and high winds resulted in extreme wind chills during the day on Thursday the 19th and Friday the 20th. Morning lows on the 20th again reached record levels at most locations across Delaware and Chester County, PA (Figure 4). The cold air hung on for one more day, especially across southern Delaware where temperatures dropped to record levels and reached as low as -10°F in Gumboro, DE on the morning of February 21st (Figure 5).

Snowfall

Snowfall Accumulation Feb. 17, 2015

Figure 6. February 17th, 2015 snowfall totals based upon DEOS station observations.

Snowfall Accumulation Feb 21, 2015

Figure 7. February 21st, 2015 snowfall totals based upon DEOS station observations.

The first significant snowfall of the season for much of the State occurred on February 17th. With cold air in place across Delaware, a storm system moved across the southeastern United States, exiting the coast near the Virginia/North Carolina border. With the storm taking a southerly track, snowfall totals across Delaware were highest in Sussex County where over 6 inches of snow fell in some areas (Figure 6). The northern half of Delaware saw snow totals in the 2 to 4 inch range. A second storm impacted the State on Saturday the 21st, dropping more than 5 inches of snow in parts of New Castle County and Chester County, PA (Figure 7).

 
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Cars in Wilmington

Cool Temperatures and Near Normal Precipitation Characterize Delaware’s Climate During 2014

Posted on | by Dan Leathers
Posted on Mon 01/26/15 , Updated 02/01/16

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Figure 1. Delaware statewide annual mean temperature (°F) 1895-2014.
December monthly temperature anomalies.

Figure 2. Delaware monthly temperature anomalies.

Annual Temperatures

Statewide mean annual temperature in 2014 was 54.8°F according to preliminary data from the National Climatic Data Center (NCDC). This was 0.6°F below the 1981-2010 normal of 55.4°F (Figure 1) and was the coolest year in Delaware since 2003.

Monthly temperatures varied greatly throughout the year (Figure 2). The first four months of 2014 saw much below normal temperatures accompanied by heavy snowfall across the State. Although late spring and early summer saw a return to above normal temperatures, the late summer climate was cooler than normal, a welcome respite from the summer heat for many residents. The year ended with a return to warmth in three of the last four months.

Annual Precipitation

Statewide precipitation in 2014 averaged 43.49 inches, 0.84 inches below the 1981-2010 mean of 44.33 inches (Figure 3).

Monthly precipitation anomalies varied between positive and negative throughout the year, with six months of above normal and six months of below normal precipitation (Figure 4). None of the monthly precipitation anomalies were large, leading to the near normal annual total.

Statewide Spatial Averages

According to data from the Delaware Environmental Observing System (DEOS; deos.udel.edu), mean annual temperatures were below normal across the entire State with the largest negative anomalies found in coastal Sussex County (Figure 5).

Precipitation across the region varied substantially in 2014, ranging from just under 39 inches to greater than 50 inches across the region (Figure 6).

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Figure 3. Delaware statewide annual precipitation (inches) 1895-2014.
Delaware monthly precipitation anomalies.

Figure 4. Delaware monthly precipitation anomalies.
2014 mean annual temperature departures from the 1981-2010 mean based upon DEOS station data.

Figure 5. 2014 mean annual temperature departures from the 1981-2010 mean based upon DEOS station data.
2014 annual precipitation totals based upon DEOS station data.

Figure 6. 2014 annual precipitation totals based upon DEOS station data.
 
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February 2014 Continues Cold and Snowy Across Delaware

Posted on | by Dan Leathers

 

 

February Temperatures

 

Statewide average temperature in February was 34.5°F according to preliminary data from the National Climatic Data Center (NCDC). This was 2.0°F below the 1981-2010 normal of 36.5°F (Figure 1). Although below normal for the most recent 30-year period, February 2014 was only the 54th coldest since records began in 1895.

February Precipitation

 

Statewide precipitation in February averaged 4.23 inches, 1.32 inches above the 1981-2010 mean of 2.91 inches (Figure 2). Many areas of the state saw substantial snowfall during the month with portions of northern Delaware and Chester County, PA receiving between 15 and 30 inches (Figure 3).

Statewide Spatial Averages

Mean monthly temperatures were well below normal across the entire state and at all DEOS stations (deos.udel.edu) in February, with the largest negative temperature anomalies found across northern Kent and New Castle Counties (Figure 4).

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Snow on Barn

Winter 2013-2014 Climate Update

Posted on | by Dan Leathers

Below normal temperatures and heavy snowfall characterized Delaware’s Climate during the 2013-2014 winter season.

 

Winter Temperatures

Preliminary data indicates that Delaware’s winter temperature was below the 1981-2010 normal for the third time in the last five years. The Statewide mean winter temperature of 34.9°F was 1.4°F below the 30-year normal of 36.3°F. Although slightly cooler than normal, this winter’s temperature was actually near the middle of all winters since records began in 1895 (Figure 1).

Winter Precipitation

Cold temperatures were accompanied by above normal precipitation across the state during the winter season. The statewide mean precipitation of 12.35” was 2.59” above the 1981-2010 normal of 9.76”, and was the first winter since 2009-2010 with above normal values (Figure 2), and the 18th wettest winter since records began in 1895.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that mean winter temperatures across the state were cold throughout, with the coldest conditions found along coastal Sussex County and in sections of northern Kent and southern New Castle Counties (Figure 3). The spatial patterns of average maximum (Figure 4) and minimum (Figure 5) temperatures were similar to that of the mean winter temperature across the First State.

The colder than normal temperatures, combined with above normal precipitation resulted in heavy snowfall totals across the entire State during the 2013-2014 snowfall season. More than twice the seasonal average fell across the entire state with some locations receiving nearly three times their average accumulations. Snowfall totals ranged from over 50 inches in northern New Castle County and Chester County, PA to greater than 25 inches across extreme southern portions of Delaware.

 
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