Marshall A. Atwater

Forecasts of snow amounts for the coming winter are difficult to make.  I use a method that assumes the patterns established in the summer (data from May, June, July) will continues thru the following winter.  Then I find a summer pattern in the NOAA data for Bradley Airport and determine what the following winter produced.  Last year, there was a major change in the pattern at the end of the year from warm and wet to warm and dry.  The warm and dry pattern continued thru the summer.  One of the largest influences on the seasonal climate normality is the ENDO index of sea surface temperature in the equatorial Pacific.  The forecast for the coming winter is that it will be negative.

The past summer at Bradley Airport had the highest average temperature with little rainfall.    The data for the 10 warmest years in maximum temperatures since 1949 are shown in the table.  I also added the ENSO index where the index is negative for La Nina years.  Snowfall for the following winter are also included.

Year	N 90+	T Max	T Min	T Avg	Rain	ENSO Index	Snow DJF+M
2010	26**	84.78	62.74	73.76	9.52	4.1	84+2
1999	26	84.80	61.02	72.91	5.97	2.0	Missing
2019	24*	84.92	62.09	73.51	8.67	0.5	23+7
1995	21*	85.17	60.14	72.65	7.41	1.3	Missing
1971	23	85.24	59.31	72.27	9.25	-.7	34+3
1973	25	85.34	63.47	74.41	11.34	-1.8	24+14
1966	30*	85.72	60.92	73.32	8.58	-1.3	48+34
2016	24	85.95	61.76	73.85	8.4	-.3	41+20
1949	17**	86.19	61.19	73.69	3.46	-1.7	37+8
2020	39	86.42	62.53	74.48	4.42	-1.2 p

          p   Predicted          Days with 100 deg = *     DJF+M=December, January, February and March 

The first four entries are the coolest of the 10 years and they had a positive ENSO index for the following winter and will not be used.  The two years that are closest in average temperature are 1973 with 1966 being the cooler year having lower nighttime temperatures.  The average snowfall for these years give 34 inches for DJF and 11 inches for March.  However March is highly variable ranging from 3 to 34 inches. The total forecast for the year is 45 inches of snow at Bradley Airport.  Higher amounts would be expected.in the hills and lower amounts along Long Island.  I expect this to be more accurate than the forecasts for 2100.

In trying to decide significant weather events this year for Connecticut using Bradley Airport meteorological data., it was decided to start with  the summer average temperature and rainfall with possible modifications with September and October.  There were no one significant weather features this year.  The summer was rather warm without any dry spells.  The trend has continued into the fall.

The average data for the summer is:

Maximum Temperature              84.8

Minimum Temperature               62.1

Average Temperature                  73.5

Precipitation                                 8.73 inches

Years with similar summer statistics included the following years and the following winter snow  totals are given in the following table.

Year      Maximum Temperature              Precipitation     Snowfall

2010     84.5                                               9-.52                   84

1995     85.1                                               7.44                    85

1966     85.7                                               8.75                    59

Then I examined the data for September and October to see how the data was confirm in those months.

September

Yr                        T max    T Min    Precip

2019                   77.1      52.4      1.94

2010                   78.8      56.3      2.55

1995                   74.4      50.0      3.15

1966                   74.5      52.3      6.05

October

Yr                        T max    T Min    Precip

2019                   64.6      45.7      6.94  

2010                   62.7      42.9      5.31

1995                   67.7      43.9      9.46   

1966                   64.1      39.6      4.23

An examination of the monthly distribution shows the following average snowfalls

Nov Dec                           12

Jan                                    30

Feb                                   20

March                              10

Total                                 72 inches

Each of the three years the snow occurred within a six week period.  Two years were in January and one year was February/March.  Most of the snow will be from mid January to mid February.  How is that for going out on a limb over drifting snows.

The average snowfall at Bradley is 45 inches.  There were 40 inches in 2018-9.

Last October I made the following snowfall forecast for Bradley Airport.

I will estimate the snowfall to be 28 to 32 inches at Bradley.  The average snowfall is 45 inches.

The winter is over with the following monthly snow totals.’

Nov.                       8.0

Dec                         0.2   

Jan                        12.4

Feb                          9.2

Mar                       10.2

Total                     40.0

The largest one-day snowfall was the Nov 15 storm with 8 inches with most of it occurring between 5 PM and midnight.  The total snowfall was less than the normal 45 inches with little snow occurring during the two months after the first storm.

The year 2017 had relatively normal weather.  The drought ended in March.  The resultant  snowfall exceeded the original seasonal prediction.  The summer has near normal temperatures with fewer than normal number of days with 90 degrees.  October turned out to be the warmest October as cold air failed to arrive.  The National Weather Service forecasted near normal temperature and above normal snowfall for near I-95 in southern New England.

Based on the record October temperature, I examined the following winters in which the October temperatures were nearly the same.  The four warmest years at Bradley Airport were 1963, 2007, 1971, and 1949.  In   addition, the first two years had below normal days with 90 degrees.  The following winters had 52 and 45 inches of snow, on the higher side of normal.  The next two years had 50 and 42 inches of snowfall.  Three of the four years had temperatures slightly above normal and 1963 was about 3 degrees colder than normal.  1963 winter was heavily cooled by the presence of dust from the eruption of the volcano at Mount Agung in Indonesia.  There are also reports of a possible new eruption in the near future for this volcano.

Based on the analysis, the prediction is for 45-50 inches of snow at Bradly Airport with near normal temperatures.  In general, there is less snow near the coast and higher amounts of snow in the northwestern and northeastern hills.

 

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.