Well, 2016 has ended. The Presidential elections are behind us and the Trump Era is about to start. While the headlines may change, the everyday lives will continue with the same issues as previously. The weather will continue to act in its own way. The winter has started and appears to have near normal temperatures with periods of several days slightly above or below normal. The snowfall is slightly below normal. The drought in Connecticut continues and ended 2016 with a deficit nearly 20 inches over the past two years. December was about 2/3 of an inch below norm. Like all trends in weather, the drought will eventually end.
Author: Marshall Atwater
Connecticut Drought 2015-2016
The average precipitation in Connecticut is about 44 inches per year. In 2016, about 26 inches of precipitation has been recorded at Bradley Airport. We are currently 40 per cent under the normal amounts from March through last week. Even normal precipitation for the year will be less than 34 inches for the year.
A review of data from Bradley Airport shows only 8 years since 1950 that had less than 38 inches. The years are shown in the table.
| Year | Total Precipitation (inches) |
1965 |
29.45 |
| 1980 | 31.69 |
| 1957 | 32.22 |
| 2001 | 33.03 |
| 1964 | 34.55 |
| 1981 | 35.15 |
| 1985 | 36.88 |
| 1963 | 36.92 |
The year 2015 was also below normal and only had 39.21 inches, making the current drought in the longest since the drought 50 years ago. One of the worst of the recent droughts and which was one of the longest droughts in Connecticut occurred from 1963 to 1966 with 3 of the years being among the top 8 dry years. The dryness affected both agricultural production and created water supply problems.
2016 Winter Forecast
As we approach the end of 2016, it is now time for a winter forecast. 2016 is noted for its dryness and will be 12-15 inches of precipitation below normal. It has also been generally warmer than normal. The normal snowfall at Bradly Airport is 45 inches.
Several organizations recently issued winter forecasts. One can look at the Old Farmer’s Almanac that says “Winter is back” and predicts colder than normal temperatures with above normal snowfall for southern New England. The Weather Bureau forecasted the winter to be near normal in temperature and precipitation. AccuWeather predicted “Frequent storms across the northeastern U.S. this winter may lead to an above-normal season for snowfall. The Northeast is going to see more than just a few, maybe several, systems in the course of the season…. Overall, it’s predicted that the region will total a below-normal number of subzero days, though the temperature will average 3-5 degrees Fahrenheit lower than last year.” The Weather Channel is forecasting colder than average in New England and probably more snow than average snowfall. Meteorologist Judah Cohen, of the private forecast firm Atmospheric and Environmental Research in Massachusetts, relies on Siberian snow cover in the month of October to discern how key weather patterns will likely evolve downstream, above North America and Europe, during the winter. Cohen thinks this winter is going to be a predominantly cold and snowy one from the northern Plains to the Upper Midwest on southeast to the Mid-Atlantic and Northeast. http://mashable.com/2016/10/21/winter-outlook-snow-cold/#M7QH.LqMskqL)
I examined the data at Bradley Airport to find similar years and used those years to make a forecast for the forthcoming winter. Most similar years had between 35 and 42 inches of snow. In general, the warmer years had smaller snowfall amounts. Based on this, I predict that 36 inches of snow will fall this winter and that the temperature will be near normal. I estimate about 5 inches will fall in December.
Northwestern Connecticut Visit
It was a day in late October during the peak of the autumn colors when we decided to take a trip to northwestern Connecticut, where we have not been in 20 years. As we left Tolland, the sun was shining through the trees highlighting the yellow color. The trees in the lowlands were nearly bare, having been bright red a few days earlier. Traveling on Rt 84 through the Connecticut River valley, many of the trees still were green. On Rt 4 in Farmington, trees in bight yellow and red became prominent. In Unionville. The Farmington River and the trees presented a scenic view. Torrington have had some development in the eastern portions with new shopping and eating areas.
Traveling north on Rt 8 had colorful hills on each side of the highway. Traveling through Main Street in Winsted, one could see the stores on one side of the street as the side near the Mad River, which is now nearly dry. The buildings on the river side were never rebuilt after the 1955 flood had destroyed the street.
We then traveled through scenic woods to the Barkhamstead Reservoir where Rt 318 travels over the dam. There are hills on both sides of the valley that were in various reds and yellows near the peak of the season. This was probably our first visit to the dam in 40 years. We then traveled through Granby and Ellington to Tolland.
Vertical Absorption of Ground Emitted IR by Carbon Dioxide
Infrared radiation emitted by the earth needs to balance the incoming solar energy to keep the climate in equilibrium. Radiation is emitted by the surface. However, before it reaches space, it is absorbed within the atmosphere by carbon dioxide and water vapor. The amounts of energy absorbed depends on the concentration of CO2 and water vapor, often called greenhouse gases. The absorption results in a temperature increase with IR energy emitted in both upward and downward directions or converted into other forms of energy. The radiation calculations are well defined and many models have been developed for the calculations. Here we will use an early model developed by the author that were used in early meteorological mesoscale models (Atwater, 1971). More recent models may use line by line calculations.
The ground is the input source of IR to the atmosphere. There is very little that is written on the vertical absorption regarding the surface flux which is dependent on the path length of the absorber. The emission of IR and conversion to other energy forms at the various levels will not be examined here.
The results for the surface transmission (1-absorption) are shown in the following graph for total CO2 and water vapor transmittance (CO2=280ppm) and for carbon dioxide transmittance at 280ppm and 560ppm for the lowest 300 m.. It is assumed that the carbon dioxide absorbs 18.5% if the total spectrum.
The results show that about half of the surface IR radiation is absorbed within 150m (about 20 mb) of the ground, both for the total spectrum and the CO2 portion of the spectrum. With the increase CO2 concentration, half of the energy in the CO2 spectrum is absorbed within 50m of the surface and 2/3 are absorbed by 300 m . More than 99% of the CO2 spectrum is absorbed by 7000m.
The amount of radiation absorbed in each of the lowest layers is shown in the following table.
| Layer Thickness mb | Layer Thickness m | Top of Layer m | Radiation Differential W/m2 |
| 1 | 8 | 8 | 3.2 |
| 2 | 18 | 26 | .5 |
| 3 | 26 | 52 | .2 |
| 4 | 34 | 87 | .07 |
| 4 | 35 | 121 | .04 |
| 4 | 35 | 156 | .01 |
| 5 | 44 | 200 | -.01 |
Most of the increase in absorbed radiation is in the first 8 meters of the ground with much of the remaining radiation in the next layer. About 90% of the increased absorption due to a doubling of the carbon dioxide occurs within 26 m (about 3 mb) of the ground. Above about 175 meters, the absorption of the ground flux is reduced due to reduction of infrared flux reaching the levels.
In most climate models the lowest layer is often 10mb thick with the increased absorption assumed to occur in a much deeper layer. In an earlier paper, Raisanen (1996) did a study of the vertical resolution needed to minimized errors in climate models for radiation calculations and found a number of systematic errors near the surface when the layers were thickened. He attributed this to sharp differences in temperature in the region rather than the rapid absorption near the surface of both water vapor and carbon dioxide. Models with layers too thick may not properly account for conversion of radiant energy to convective energy. The impact on climate models should be further investigated.
Atwater, M.A., 197l: The Radiation Budget for Polluted Layers of the Urban Environment. J. Appl. Meteor., 10, 205-14.
Raisanen, P, 1996: The effect of vertical, resolution on clear sky radiation calculations: tests with two schemes. Tellus, 48A,403-423.
New England Temperature Trends 1965-2015
Global warming has been occurring since the Little Ice Age in the 1600s. Recently, it appears that 2015 is one of the warmest years for the global average surface temperature. El Niño occurred in 2015 and contributed to some of the increase in 2015. The late 1960s was the coolest period in the last half of the 20th century. The average global temperature increased 1.0°C (1.8°F) during the period.
First order airport stations are selected from each of the New England states. The data was processed for 1965 to 2015 and includes minimum and maximum temperature and precipitation. The daily data was processed and averaged over monthly, seasonal, and annual periods. Each station was processed independently and regression coefficients were calculated using Excel. Metadata for each of the sites were examined to determine changes in station locations. The results for the regression coefficients are shown in the table in °F/decade.
Table: Regression coefficients in °F/decade for seasonal Minimum and Maximum temperature.
| Winter | Spring | Summer | Fall | |||||
| Station | Min | Max | Min | Max | Min | Max | Min | Max |
| Caribou | .954 | .577 | .401 | .208 | .305 | .125 | .577 | .680 |
| Portland | 1.073 | .676 | .524 | .490 | .628 | .038 | .586 | .464 |
| Burlington | 1.470 | 1.028 | .786 | .774 | .696 | .333 | .656 | .805 |
| Concord | 1.222 | .651 | .486 | .460 | .589 | .151 | .576 | .550 |
| Boston | .427 | .449 | .398 | .285 | .295 | (.017) | .295 | .302 |
| Providence | .788 | .710 | .453 | .502 | .465 | .244 | .634 | .391 |
| Hartford | .636 | .691 | .190 | .301 | .280 | (.108) | .389 | .281 |
| Bridgeport | .595 | .466 | .472 | .511 | .470 | .244 | .203 | .172 |
The station with the largest increasing trends is Burlington. Examination of the time series of temperature show large increases starting in 1973 and in 2008. A review of the metadata for the station show the station moved 55 feet to a lower elevation in Jan 1973. A new terminal for the airport opened in Oct 1973. The terminal was further expanded in 2008. Substantial suburban homes and the central developed area are to the west of the airport. These sudden increases were due to the urban heat island effect from the increased activity at the airport and development surrounding the airport.
Bridgeport is located on the shores of Long Island Sound and is heavily influenced by the temperature of water in the Sound. Temperature data is available for the Sound starting in 1976 and increases 0.6°F per decade. This accounts for much of the trends at Bridgeport when compared to Hartford and also appears to be an influence on the Providence results.
The results show that the temperatures are summarized as:
- generally increase more rapidly at night than during the daytime in northern New England.
- In southern New England, the temperature rates are nearly the same during the cooler months.
- During the summer, all night temperature trends are increasing more rapidly than during the daytime.
- In general there is little temperature change in the summertime maximum temperature trends with southern New England showing a net cooling over the past 50 years away from Long Island Sound.
- The winter temperatures are rising faster than the global temperature
Review of “The year without a summer: 1816”
“The Year Without Summer: 1816” by William K Klingaman and Nicholas P. Klingaman was a very interesting book for readers that want to see the effects of weather on people that led to historical changes. In April 1815, a massive volcanic eruption occurred on Mount Tambora in Indonesia with ash going 18 miles into the atmosphere. The explosion was heard 250 miles at sea. The next day Napolean returned to Paris after being sent to Elba. Thus the book starts a two year journey that interweaves the effect of the resultant dust clouds that lowered the World’s temperature and its effect on the people. In the northern hemisphere, 1816 became as the year without a summer.
Most of the World did not know about the eruption at the time so the mysterious changes that occurred resulted in many concocted reasons for the low temperatures. There were excessive rains, floods, frost and early snowfall across Europe and the Unuiterd States. Food shortages, religious revivals, and westward migration of people occurred in the United States. In Europe, there were famine, food riots, typhus epidemics and many stable communities were transformed into wandering climate refugees. It also had an impact on the arts. All of the changes occurred before any of the rapid communications that started decades later.
Meriden Hubbard Park
Hubbard Park in Meriden was developed in 1900 and consists of 1700 acres. It contains a 4 acre lake near the entrance and a tower on the a 1000 ft mountain with views from Long Island Sound to Massachusetts. My earliest memories of the park was going to the park with my grandmother and eating at the restaurant that was adjacent to the lake. A few years later, the family would go to the park for ice skating in the winter. And it was a good location for a proposal, as I’m sure many other couples have also appreciated the location. So it was nice to drive thru the park on our recent anniversary and see minimal changes in the park since my youth.
Weather on A Meteorologist’s Vacation
Most people probably assume a meteorologist would not take a vacation if the weather is bad. But the forecasts often turn out wrong and beyond a week are of little value. Recently I took a 10 day vacation from driving from Connecticut to Virginia, and North Carolina. We left in brilliant sunshine, but the weather forecast indicated a cloud bank was visible to the south. By the time we got to the New York City area on Wednesday, it was completely overcast. Showers started in the evening id Columbia MD. The next morning, heavy rain occurred on the drive to Williamsburg. There were severe thundershowers at night, Rain would occasionally occur for the next day and a half. It was completely cloudy as we drove to Raleigh NC. The sun appeared on Sunday afternoon finally as we stopped in Greensboro and then in Asheville. On Tuesday and Wednesday, it was partly cloudy for our visit to Mt Pisgah and to Brevard. The return on Thursday and Friday started with a few snow flakes and was punctuated with heavy showers that cut down the visibility for thew next two days.
Climate Change in Connecticut
For the past quarter century, global warming have been the subject of many scientific studies that relate to its causes and the resultant effects. An often cited study in Connecticut showed the large reduction in shade tobacco production was highly correlated with the increase in the global temperature. However the tobacco have no idea what the global temperature is when compared to the local climate. Often studies use the global warming models to provide the local data at a proposed future date to determine local effects. However, the climate models lack verification and the study on possible effects are what “could happen.”
It was decided to look at the climate in Connecticut over the past half century. Data was obtained for Bradley International Airport that represents interior areas and Bridgeport Sikorsky Airport on the coast. The period chosen was a period in which missing data was not a factor in the analysis. Bradley Airport was developed after World War II and had several periods of missing data in the 1950s. Therefore the period of analysis selected was December 1960 to February 2016. The seasons chosen will follow the meteorological seasons where winter is December thru February. Both sites are first order NOAA weather stations and are well maintained. Temperatures were examined on a seasonal basis for both the maximum and minimum daily observations.
The mean annual temperature increased 2.1°F during the period. A running average showed relative warm temperatures in the 1970s with gradual increases after 1990. Years with maximum temperatures were 1973, 1991, 1998, 2006, 2010 and 2012. However, variations of 3 to 4°F occurred within two years numerous times throughout the period. The temperatures were then examined on a seasonal basis for the maximum and minimum temperatures
The winter of 1960-61 was the coldest winter during the period with the minimum temperature 5 days below -18°F and only 7 days that remained above 32°F. There were 18 days below zero and 28 days between 0 and 10 days. The minimum temperature show a 5°F increase over the period with relatively high temperature in the mid 1970s and about 2000, after which they tended to decline. The warmest winters were 1997-8, 2001-2, 2011-2 and 2015-6. Year to year variations were often 6-8°F.
It should be noted that the minimum temperatures are primarily affected by the amount of water vapor in the air. The winter maximum temperatures increase 4.5°F during the period with the warmest in 2001-2. Average temperatures became cooler in later years.
The highest summer night minimum temperature occurred in the 1970s with a value of 63.5°F. The temperatures then cooled until the 1990s with warmer temperatures at the current time with a total increase of 2,1°F. The daytime maximum temperature was highest in the 1970s and gradually cooled in late years with a net cooling of 0.2°F during the period. This period of net cooling in the summer maximum temperatures extends over most of interior New England. Year to year changes in the temperature varies about 4°F with 85°F for the summer maximums. The average number of days above 90°F decreased about 1.6 days during the period with a similar increase in the number of 80 degree days.
Bridgeport is located directly on the shore of Long Island Sound and is heavily influenced by its temperatures. Available temperatures for the Sound show that the temperature increased by 2.1°F from 1976 to 2011. The increase is similar to other observations along the Southern New England coast. The temperatures at Bridgeport increased at about the same rate as the water temperatures.
The net effect of climate changes can be summarized as follows.
- Temperatures at night are warming faster than the day. A previous study showed there are fewer days of very low temperature in recent years.
- Winter temperatures have cooled since 2000
- Maximum summer time temperatures show no increase during the period 1961-2015 with a small decrease in 90 degree days
The effect on the inhabitants would be slightly reduced winter heating bills. I would expect minimal long term effects on the plants or animals in the region with a larger effect resulting from the larger year to year changes in temperature.