Articles by Cegeon J. Chan
August 28, 2009
With the Obamas in Martha’s Vineyard and the passing of Senator Kennedy, there hasn’t been a shortage of national news coverage of Massachusetts this past week. Nonetheless, tropical storm Denny is jockeying for attention as it makes its way towards Boston. Although there’s significant uncertainty in the storm’s track (and hence how much rain will fall here on campus), there is confidence in the prediction of the storms intensity. Because of the surrounding dry air, the upper-level convergence, and a southern shift of the jet stream, Denny will likely not become a hurricane.
May 12, 2009
It’s becoming that time of year when terms like “pop up thunderstorms” or “hit-or-miss showers” are often found in the forecast. When one minute it is sunny, the next it can be pouring rain. As we transition to the summer season, if there is sufficient convection, moisture, and lift, this can trigger thunderstorms. Today’s chance of thunderstorms may make you wonder how there can be thunderstorms when it’s not that hot. This is because the convection from today’s scattered thunderstorms is “upside down.” Typically, convection is trigged from the strong heating at the surface. Instead, the instability here is from the cold air aloft. This too can drive buoyancy differences and help initiate thunderstorms.
April 28, 2009
A TV meteorologist can make a perfect prediction, but yet, on days like yesterday, the public can be outraged by what they perceive as a “busted forecast.”
March 20, 2009
Did you feel like there’s been extra pressure on you? Maybe it was due to all of your professors conspiring to schedule their exams all on the same week? While that could be true, it could from the air column above you exerting extra pressure instead. There has been a slow-moving high pressure system that has dominated the eastern half of the US. Over the last seven days, the sea-level pressure in Boston has averaged about 1025 millibars — roughly one to two standard deviations above normal. That system has moved well off the coast, but another one has already moved in to take its place. For those graduate students, MIT athletes and others stuck at MIT during spring break, the good news is that this system too will also be a slow-mover, so another rain-free stretch of weather is expected over the next seven days.
February 27, 2009
Sure the calendar doesn’t say winter is over until March 20th. But meteorologists are impatient; they don’t wait until that date to close the chapter on winter. Instead, they consider December, January, and February (DJF) the winter months. (Meteorologists are also so impatient that the hundreds of weather stations across the U.S. have been programmed to report the hourly meteorological conditions seven minutes before the top of the hour.) With February coming to an end tomorrow, was the DJF temperature in Boston below average? You don’t need me to tell you that the answer is yes, but not as much as you might think. Surprisingly, December and February were slightly above-normal, while January was a whopping four and a half degrees Fahrenheit colder than normal. Thus, as a whole, DJF will turn out to be one degree Fahrenheit below normal.
February 3, 2009
What would have happened if you went to Caltech instead of MIT? What would life be like if that hobby or activity you’ve spent years pursuing was never introduced to you? Just like in real life, the track of weather systems has a full spectrum of various, but plausible, scenarios, and we generally focus on what actually transpired. But every so often, we ask ourselves, what would have happened? What would have happened if I had asked that guy or girl out on a date? In the version of today’s weather the question is: what would have happened if the jet stream shifted less? For about 5 days last week, all weather models had a major storm debilitating the northeast today. Forecasts of three feet of snow and wind gusts in excess of 80 mph were plentiful.
November 4, 2008
Can today’s weather affect the US election? According to an article in the June 2007 edition of the Journal of Politics, it can. In any election, rain and wind can impact voter turnout. Although there is likely a low correlation, there appears to be a signal in this study: rain benefits Republicans. Because democrats are more likely to live in urban areas, rain will impact Democratic “peripheral” voters more. The city folks are likely to have longer time outdoors, such as walking to polling stations, waiting for public transportation and in longer lines at urban polling places. As a result, these peripheral voters are presumably less inclined (or even less able) to go vote, and hence fewer democrats show up when it is raining. According to the study, for each inch of rain (above normal), the Republican presidential candidate received an extra 2.5 percent of the vote. So in a close election, rain can impact the election results.
October 14, 2008
There are all kinds of fronts in the weather world. The traditional ones are the cold and warm fronts. But there are also the occluded, stationary, polar, and arctic fronts. My favorite one is the so-called back-door cold front (yes, the words back and front are used to describe the same phenomena). What they all have in common is their depiction in separating two regimes. Its like an intervening friend who tells you not to go out with this person because he or she is simply trouble. In this case, the friend is the front, the one trying to separate the two parties.
September 16, 2008
When people ask “When’s the best time to visit Boston?” I smile and think to myself, “could they have asked an easier question?” September is certainly the best time. Climatologically, this is the month with the most number of sunny days. Combine that with the comfortable temperatures, this is the month where anybody would be able to enjoy the outdoors (OK, maybe not those pesky skiers). Excluding the effects of the two tropical storms, this September is no different. In fact, if you blindly believe the numerical weather prediction models, there will not be any rain for the next two weeks!
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August 25, 2008
Welcome Class of 2012! From moving into to your dorm to outdoor events, the weather (so far) has shown its sunny side. The weather machine (the dome ball atop the Green Building) has provided five straight virtually cloud-free days. However, this afternoon will mark a short disruption to this pattern (a reboot), in the form of a cold front.