Thursday, September 11, 2008

A summer in review!

Summer ended on August 31st, the day before Labor Day, well for climate researchers at least, who define the summer as June, July and August. So it’s definitely worth a minute or two to look over the climate of the summer than has come and gone. But before I do an apology on the lack of postings over the past week and a half. I was off to see a dear old friend get married in Alabama and the beginning of the school year has left me reeling… now without further ado, back to blogging.

When it comes to the weather, our brains do a poor job recollecting past climate events. Nearly everyone has something to say about things have changed, “when I was a kid it rained almost everyday, now it never does” or “it used to be cold in the winter when I was growing up, now it’s so mild!” But one would assume that our brains can at least recall how the past few months have been relative to “normal.” Based on my experiences the past few months, I think it’s clear that humans can’t even do that.

Okay quick question for you, was this summer warmer or colder than “usual?” Was it wetter or drier? How often do you recall it getting about 90? Write down your answers, and see how well you did recalling the summer. For the record, I thought it was a very wet summer and that it was below average in terms of temperature, with maybe a week or so above 90.

Summer Summary:
Temperatures
Well, I’ll violate a cardinal rule of writing and tell you the answer first. It was warmer everywhere in the New York Metro area this summer than average. It was in fact, quite a bit warmer than average. In New York city (JFK airport) it was 2.2 degrees F above average. On Long Island (Islip airport) and Westchester (Westchester airport) it was only slightly above average, coming in at +0.8 and +0.3 degrees F respectively.


The figure to the right shows the national temperature anomaly for the summer. It was warm in the Northeast and hot along the west coast.





































JuneJulyAugustSummer Ave
White Plains+2.3+1.0-2.3+0.3
J.F.K.+4.6+2.5-0.5+2.2
Islip+3.1+1.3-1.9+0.8

June had the greatest temperature anomaly (or deviation from average) across the region. A heat wave from June 7 to 10th brought the thermometer to 95 across the region, and produced days that were 10 to 15 degrees warmer than average. Excluding the heat wave (and a few days at the end of the month) the remainder of the month was at or near average. In total there were four (five in the city) days that the thermometer reached 90 across the region. A typical June at Islip airport has 1.9 days above 90 (JFK averages 1.7), for comparison.

July was also above average across the region, although to a lesser degree. In July we experienced only one heat wave, from July 18th through the 22st. During this heat wave temperatures were 6 to 8 degrees above average, but outside of this period temperatures were again at or near normal. In total there were three (four in the city) days that the thermometer reached 90. A typical July at Islip airport has 3.1 days above 90 (JFK averages 4.4), again for comparison.

August was the odd month out, as it were, as it was below average across the region. 70’s and 80’s were the rule, as there were no days above 90 at any airport across the region. This is anomalous as JFK averages 2.8 days above 90 and Islip 1.4 days. There were no major warm periods, or for that matter cool periods. Nighttime lows were well below average, but daytime highs were near average. This suggests that there were a lot of clear dry days where the atmosphere could cool off quickly during the evening hours.


The figure to the right shows the temperature anomaly for August. You can see the cool pocket along the northeast, that stretched southwest across the Ohio Valley and into the Midwest. The west coast continued to broil…

Precipitation
































JuneJulyAugustSummer Total
White Plains+0.88-0.57-1.06-0.75
J.F.K.-0.04-0.62-0.43-1.09
Islip-0.54+0.65-1.19-1.08


First a disclaimer, precipitation during the summer season at station to station can be highly variable. Thunderstorms, which account for a majority of precipitation in the summer, are notoriously local. A thunderstorm can douse a region, and 10 miles down the road you can receive nary a drop. With this said, it was a dry summer with most locations receiving about 1.00” less rain than usual.

In June and July two stations come in drier than average, and in August all three stations look drier than average. Of note was July 20 – 22, where thunderstorms dropped over an inch of rain at each of the stations. Other than that, precipitation was highly random, suggesting that localized thunderstorms were responsible for the bulk of precipitation. Perhaps it was the lack of organized large precipitation bearing systems that resulted in the drier than average summer.

In Conclusion:
Well that’s it for our little memory exercise. How did you do? The conclusion is that it was a warm, dry summer. If you’re like me – you did poorly, and that bodes not so well for our species colloquial memories of climate. Next time Uncle Walter tells you how cold it was when he was your age, ask him what he thought of the

No comments: