FEMC Long-Term Monitoring Update - 2016

Climate

Project Lead: NRCC Staff Editor: Jon Katz

The FEMC Meteorological Monitoring Network

The FEMC takes meteorological measurements at 0.5, 7.5, 17, and 24 meters above the forest floor at 1300' at the canopy research tower at the Proctor Maple Research Center in Underhill, VT.
The FEMC takes meteorological measurements at 0.5, 7.5, 17, and 24 meters above the forest floor at 1300' at the canopy research tower at the Proctor Maple Research Center in Underhill, VT.

The Forest Ecosystem Monitoring Cooperative (FEMC) has been monitoring weather conditions in Vermont for over 20 years. FEMC currently operates seven meteorological stations across a range of elevations and cover types, maintaining real-time data streams and archiving of long-term data.

Weather and climate are related but very different phenomena, weather being the condition of the atmosphere (precipitation, temperature, etc.) over the short term, while climate refers to longer-term trends and seasonal patterns. Without long-term weather records it would be impossible to tease out short-term (i.e. yearly) anomalies from more ecologically significant climate trends, which makes this information critical to scientists and planners of all kinds. To add temporal and spatial depth to our summary FEMC expanded the climate summary for 2016 beyond the FEMC monitoring stations in Vermont to include trends from the surrounding 11 states (Maine, New Hampshire, New York, Massachusetts, Connecticut, Rhode Island, New Jersey, Pennsylvania, West Virginia, Delaware, and Maryland) using records from the Northeast Regional Climate Center (NRCC) at Cornell University. This regional summary provides a broader picture of emerging trends across a larger region. Much of the following regional summary is adapted from the NRCC annual summary with permission (link to NRCC summary in additional resources).

The Data

Continuous meteorological observations are taken at seven FEMC sites from the shores of Lake Champlain to slopes of Mt. Mansfield. Variables collected include wind speed and direction, air temperature, relative humidity, barometric pressure, solar irradiance, precipitation, and at Lake Champlain stations, water temperature. These variables are primarily logged as 15-minute averages. The longest record comes from the Mt. Mansfield summit station operated by the WCAX transmitter crew and supervised by the National Weather Service, dating back to 1954. Most of the other stations operated by the FEMC began operation in the early to mid- 1990s.

2016 Vermont Summary

Table 5. Monthly average deviations from long-term normal for mean, min and maximum temperatures at Mt. Mansfield in 2016. Red indicates warmer than normal months and blue indicates colder than normal months. Units are standard deviations from norms.
Monthly average deviations from long-term normal for mean, min and maximum temperatures at Mt. Mansfield in 2016. Red indicates warmer than normal months and blue indicates colder than normal months. Units are standard deviations from norms.

Overall, 2016 was the fifth warmest year on record for Vermont, with above-normal average temperatures recorded at the Mount Mansfield weather station in all months except April and December (Table 5).

The annual statewide average temperature was approximately 2°F above the average for the last 30 years, and slightly higher than the predicted value based on the last 30 years of record keeping (Figure 16).

The highest temperature recorded in 2016 was at the Passumpsic station, which saw 100°F on August 12, 2016. The Passumpsic station also observed the highest annual average temperature of 52.8°F. The lowest temperature in 2016 was recorded at the Mount Mansfield station, which saw -32°F on February 14, 2016. The lowest high (i.e. most temperate summer) temperature of 76°F and the lowest annual average of 37.3°F were also observed on Mount Mansfield, while the highest low (i.e. most temperate winter) temperature was in Waitsfield, which observed an annual low temperature of -8°F. Superlative temperatures across the state are mapped across Vermont in Figure 17.

Annual average temperature history, with long term average and 30-year trend. Figure credit: NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, Average Temperature, published November 2017 (http://www.ncdc.noaa).
Figure 16. Annual average temperature history, with long term average and 30-year trend. Figure credit: NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, Average Temperature, published November 2017 (http://www.ncdc.noaa).
Annual maximum, minimum, and average temperature across the state based on data from 33 weather stations.
Figure 17. Annual maximum, minimum, and average temperature across the state based on data from 33 weather stations.

2016 Regional Summary

The climate pattern in the Northeast during 2016 is generally one of warmer than normal temperatures with extreme local precipitation events. Most areas emerged from a warm winter to a hotter than normal summer; for many areas in the Northeast, this meant drought conditions, while for other areas in the Northeast there were periods of extreme flooding. The end of 2016 appeared to be another warmer than normal winter. Although there were local extreme snow events, the winter did not follow a single trajectory across the region.

Table 6. Average annual temperature in 2016 for the 12 states in the Northeast (°F). Table credit: NOAA, Northeast Regional Climate Center at Cornell University (http://www.nrcc.cornell.edu/regional/narrative/narrative.html) .
Average annual temperature in 2016 for the 12 states in the Northeast (°F). Table credit: NOAA, Northeast Regional Climate Center at Cornell University (http://www.nrcc.cornell.edu/regional/narrative/narrative.html) .

The twelve states of the Northeast had their third warmest year on record in 2016. The region's average temperature was 49.3°F, which was 2.1°F above normal (Table 6). All twelve states ranked 2016 among their top seven warmest years on record.

The year started with a warmer than normal winter: winter 2015-16 was the second warmest on record for the Northeast with an average temperature of 31.4°F, 5.4°F above normal. The six New England states each had a record warm winter, while New Jersey and New York both had their second warmest winters. East-central New York had record low snowfall, while deep snow from a single blizzard event fell along the southern New England coast in late January.

In the spring, arctic inputs led to frigid temperatures, particularly in New York and New England in early April. On April 4 and 5, temperatures were up to 30°F below normal, with a few sites having their all-time coldest April temperature on record. The cold spell significantly damaged some fruit crops that had budded early.

Warmer than normal temperatures returned for the summer months. The entire Northeast had its warmest August on record with an average temperature of 71.8°F, 3.7°F above normal. September was the third warmest on record with an average temperature of 64.5°F, 3.9°F above normal. The warm summer was followed by the third warmest autumn on record with an average temperature of 52.8°F, 2.9°F above normal. West Virginia had its second warmest autumn on record, while Delaware, Maine, Maryland, Pennsylvania, and Rhode Island had their third warmest.

Regional snowfall departure from long-term normal for the winters at the beginning and end of 2016. The winter going into 2016 was short on snow across the region, while the winter at the end of 2016 saw more snow fall in the northeast and less snowfall in the southwest of the region. Note the different scales in the two maps. Figure credit: NOAA, Northeast Regional Climate Center at Cornell University (http://www.nrcc.cornell.edu/regional/monthly/monthly.html).
Figure 18. Regional snowfall departure from long-term normal for the winters at the beginning and end of 2016. The winter going into 2016 was short on snow across the region, while the winter at the end of 2016 saw more snow fall in the northeast and less snowfall in the southwest of the region. Note the different scales in the two maps. Figure credit: NOAA, Northeast Regional Climate Center at Cornell University (http://www.nrcc.cornell.edu/regional/monthly/monthly.html).

Rainfall

The Northeast wrapped up 2016 with 40.32 inches of precipitation, 91 percent of the long term normal (Figure 18). Ten states were drier than normal, while West Virginia and Delaware were at 101 percent and 106 percent of normal, respectively. It was the third wettest September on record for Delaware and portions of southern West Virginia and central Maryland had 1,000-year flooding events, meaning rainfall of that magnitude has a 0.1% chance of occurring in a given year.

Across the 12 state region, the northeast saw below-average precipitation in 2016. Figure credit: NOAA, Northeast Regional Climate Center at Cornell University (http://www.nrcc.cornell.edu/regional/monthly/monthly.html)
Figure 19. Across the 12 state region, the northeast saw below-average precipitation in 2016. Figure credit: NOAA, Northeast Regional Climate Center at Cornell University (http://www.nrcc.cornell.edu/regional/monthly/monthly.html)

Implications

While climate variability is high, both temporally and spatially, meteorological measurements witnessed across the Northeast are in agreement with local and national assessments indicating that temperatures have increased over the past several decades (Betts, 2011; EPA, 2014; IPCC, 2014). However, it is not the general warming trends that will likely impact forested ecosystems the most in the near future. Instead, it is the increased frequency and severity of extreme climate events that are of concern to forest health professionals. The increase in extreme temperatures witnessed in 2016 are an example of the increase in variability we will continue to see under a changing climate. These extremes represent an additional stress for species adapted to cold weather dormancy, increased risk of winter injury following winter warm spells, and frost damage during spring freeze events. Even when climate conditions remain within a species' natural tolerance, differences in competitive advantages among species due to phenological changes or erratic and unseasonable temperature fluctuations could alter ecosystem structure and function (Pucko, 2014).

A very cold wood frog, North Lincoln Street, Keene.

Variable temperatures may eventually affect phenological adaptations, potentially increasing vulnerability to insects, diseases, and may have an adverse impact on major agricultural crops in Vermont such as apples and sugar maples (Grubinger, 2011; Rustad, 2012).

Acknowledgements:

A special thank you to NOAA and the Northeast Regional Climate Center at Cornell University for the generous use of their regional data and their generous permission to adapt the regional climate summary.

References

Additional Resources

FEMC Project Database Link