Wednesday, January 30, 2013

Precipitation of the past year

Yesterday I posted a look at the temperature of the past year as it was much above normal across Connecticut with the exception of November and a near-average June. Today I wanted to look at precipitation as I did from time to time in 2012 when it became a widely known on occasion because of the dry weather. Before I get to that I thought it would be prudent to post this unfortunately awful graphic concerning the current drought taking hold of the country from the U.S. Drought Monitor from the University of Nebraska-Lincoln, most of which is due to 2012's weather.

It has been a brutal stretch across the central United States with agricultural areas continuing to suffer long-term droughts. Basically the entirety of tornado alley is in need of rain or snow as soon as possible. The southeast had a difficult several years but has recovered to some degree, and the arid southwest could still use some more rainfall as well. The northeast looks to be largely in relatively good shape, and if you looked at Connecticut on a state level there would be absolutely no drought apparent by their measurements and calculations. I'll get back to that in a moment.

So how dry or wet was it in 2012 in our state? Here is the official precipitation data from National Weather Service weather and climate monitoring stations in Bridgeport and Hartford. I have listed the total precipitation followed by the respective change from long-term averages for the month and then the same for snowfall, if applicable. Snowfall liquid equivalent totals are also accounted for in the total precipitation.

2012 in Bridgeport:
January: 2.98 (-0.12), 7.4 (-0.5)
February: 1.58 (-1.21), 2.2 (-5.6)
March: 1.04 (-3.01), T (-5.0)
April: 2.97 (-1.16), T (-1.1)
May: 4.57 (+0.77)
June: 4.39 (+0.78)
July: 4.35 (+0.89)
August: 3.33 (-0.63)
September: 7.00 (+3.52)
October: 3.24 (-0.40)
November: 1.22 (-2.17), 8.4 (+7.7)
December: 4.32 (+0.99), 7.8 (+2.7)

2012 in Hartford:
January: 2.96 (-0.27), 6.8 (-5.5)
February: 1.47 (-1.42), 5.9 (-5.1)
March: 1.52 (-2.10), 1.7 (-4.7)
April: 3.02 (-0.70), 0.0 (-1.4)
May: 3.27 (-1.08)
June: 4.22 (-0.13)
July: 4.34 (+0.16)
August: 4.12 (+0.19)
September: 4.57 (+0.69)
October: 4.00 (-0.37)
November: 0.40 (-3.49), 2.9 (+0.9)
December: 4.55 (+1.11), 12.9 (+5.5)

Before I even say anything in regard to those numbers I'll reiterate that we should all understand one day, one week, one month, or one year - this is weather, not climate. Think of weather as a measure of the atmospheric conditions occurring at the current time, or over a short period of time at some point in history, whereas climate is the long-term accumulation of weather data. When I comment on a year or a month I am not saying it is all the proof we need of our new climate reality, just as we cannot attribute Hurricane Sandy to the negative changes humans have wrought on the Earth. Some organizations and individuals use this both ways - fighting for climate change by pointing out a specific storm, or claiming that the planet is peachy or getting colder (blatant and absurd lies cherry-picking data at best) because we had a cold winter or a hot summer day. The temperature of the Earth and its oceans has been increasing at dramatic rates over decades due to our actions and technological developments we have made in the last few centuries, and it is important to see the grand scale while realizing specific weather events and time periods will be altered because of the climate. The end of the 19th century had some incredible winter storm systems on a level that no one alive has ever seen, and if that were happening today it would be wrong to say, "Oh, three feet of snow? Global warming" and look at it as more than an isolated event or even a series of them. However, as we watch the thermometer going up and the seas rising, with parts of the world exposed from their icy cover for the first time in thousands of years, it is worth watching patterns that develop here.

One such pattern seems to be our trend of shattering the classic four-season weather that is buried deeply in New England lore. Once again we had a very early snowfall with the November Bridgeport total being an all-time record. Another November all-time record was the lowest amount of precipitation ever measured for the month at Hartford. This was quickly amended there with the all-time December record snowfall of 12.9 inches. The fall season is not normally anywhere near this wintry, and even though the two stations, so close yet so far apart in terms of sensible weather, had much different snowfall totals for November and December they both ended up with a little over 15 inches during the period.

The ensuing lack of snowfall for the remainder of the winter was well known to many. We certainly received some, but more fell in the fall overall, and the beginning of 2012 was marked by a lack of all forms of precipitation that became increasingly worse through March when temperatures soared in the middle of the month and record highs were shattered. As I have written about before here this accelerated the life cycle of vernal pools and began to dry them out very early along with other streams, creeks, and small ponds, sometimes leading to poor breeding years for a multitude of species. We may not always enjoy it but we need the snow, ice, and frigid air in the winter months in order to maintain a semblance of normalcy for our environment in the spring and summer.

April improved dry conditions a little, and the scales balanced a little more heading through the summer. The difference between the two stations is really something, and being on the coast seems to continually provide us with more precipitation than those inland, making for a small state with vastly different water levels at times. Even though we on the coast were somewhat near normal by the latter half of the summer it did not feel like it as higher than average temperatures and the lack of water in critical seasons meant that we had dried out wetlands and evaporated vernal pools. When people asked me about the terrible drought that was going on I pointed them to the precipitation by month and the temperature deviations. If higher than average temperatures become a reality we will need a steadily increasing supply of liquid to go along with it.

Guess what? This January is about to end with lower than average water and, as noted yesterday, higher than average temperatures. There is no reason to believe this will change in February at the moment, and we may be off to the races with an early start to the spring yet again and a struggle for water levels throughout most of the year. Points to our north are also snow-deprived, and I cannot see a lot of water flowing down to us from any snow melting as it does not exist for many areas.

Let's work to make sure this is not the new normal because our environment will not be able to adapt quickly enough to survive it without sustaining heavy losses.

Scott Kruitbosch
Conservation Technician

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