Humidity is the weather word of the week. The Bermuda High, which has been mostly absent this summer, will make its presence felt for the next several days. A weak Canadian high pressure system is keeping ol' Bermuda at bay today. Look for mostly sunny skies, increasing humidity, and a high in the lower 80s.
Bermuda High Finally Asserts Itself
April Heat Wave!
Cool, cloudy weather got you down this week? Fear not; what passes for an April heat wave will be here for the weekend. Why? The Bermuda High is making its first northward foray of the season, bringing July-like warmth to much of the East Coast.
Oh, the Humidity
Might we just say that Gothamist really dislikes this muggy weather. Normally we are as sweet as a sugarcube but with high humidity here today, tomorrow, next week we know we will be cranky. We're sitting on the west side of the Bermuda High, meaning lots of subtropical air is over the city. A weak cold front currently stretched across the Great Lakes is trying to sweep the sweaty air away, but it is going to take several days to accomplish the task.
Headed for the Heat
Here's a fascinating fact for impressing your friends this evening. At 8 p.m. the earth will be at its furthest distance from the sun for the year. The planet's revolution around the sun is slightly elliptical. Today we're about 94.5 million miles from the sun. Early next January we'll be only 91.5 million miles away (as demonstrated by this awesome graphic). The date of the aphelion has only a slight affect on seasonal temperatures, which are largely determined by the 23.5 degree tilt of the earth with respect to its orbital plane. The date of the aphelion changes slowly, it'll occur in the second week of July in 400 years, and in January in several thousand, and is one reason why the Ice Ages will appear again in 20,000 years or so.
Heat and Smog are Here
As tankengine's picture above attests, today's air quality is not so good. Heat, humidity, stagnant air and lots of sun have combined to raise our ozone and particulate counts high enough to warrant an Air Quality Alert. The hot and humid air are going to fall just shy of the mark needed to declare a heat advisory, but it will still be plenty miserable outside. Gothamist mentioned tips to beat the heat yesterday.
Hazy, Hot and Humid
There's a slow-motion battle of the blobs shaping up in the atmosphere above the eastern U.S. this week. So far this summer our weather has been dominated by the Beast of the East otherwise known as the Bermuda High. The clockwise flow of air around the Bermuda High brings us the heat and humidity of the tropics. Later in the week the jet stream, which is already to our north, is going to retreat further northward. This move will allow the Pest from the West, the heat wave that has been baking the southwest and southern Plains, to move northward then eastward.
What Will the Groundhog Say Tomorrow?
Last month tied January 1913 as the fourth warmest January on record. The average temperature in Central Park was 40.9 degrees, 8.8 degrees above normal. Much of the Midwest and Great Plains had their warmest January's ever. The warm trend continues into February but for how long? The clouds are giving us warmus interruptus today but tomorrow will be a sunny, warm mid-winter day. The sunshine means that Staten Island Chuck will see his shadow, predicting six more weeks of winter. Gothamist hopes whatever local dignitary helps Chuck with his duties tomorrow morning asks the rodent if "six more weeks of winter" means more of the same or a return to real winter weather.
Summer Soup
No, not a refreshing gazpacho. The air outside is more like a thin, tepid potato-leek. Maybe Gothamist should leave the metaphor and simile writing to professionals. Whatever flavor, the soup is going to be here for the rest of the week.
Watching the Sky
The forecast has changed but a smidgen since Monday. Now we're expecting temperatures in the mid-80s rather than the lower-80s through Friday. Don't be surprised if it rains, and if it does rain don't be surprised if it rains heavily, if briefly. Assuming that cold front to our north makes its way down here, our holiday weekend weather will be a welcome change: sunny, warm and dry.
Welcome to the Tropics
As you may have noticed the humidity is on the oppressive side today. Get used to it. A Bermuda High is large and in charge and not going anywhere this week. We may see some light showers over the next couple of hours. For the rest of the week, repeat after Gothamist: Mostly cloudy, warm and humid. Highs in the lower 80s, maybe warmer on Friday. Chance of showers and thundershowers later in the day. Rain may be heavy at times. Chance of rain at night. Lows around 70.
More Sunshine
It was chilly on both Saturday and Sunday morning, but not quite chilly enough to set a record. We came within two degrees on Saturday and four degrees on Sunday. Yesterday turned out especially nice and Gothamist explored northern Manhattan on his bicycle to the point of exhaustion. How did you take advantage of the lovely weather?
Comparing the Forecasts
Today Gothamist Weather introduces a semi-regular (i.e. when we remember to do it) feature in which we compare the various forecasts for our area. Since we are easily confused we'll keep this simple and just look at one element of the forecast. In honor of our hot, humid weather here are today's predicted maximum temperatures:
Previously on Gothamist Weather
- The Crossing of Venus. If you missed it, set your alarm for 2012.
It's Getting Hot In Here
Wednesday was miserable. It was hot, humid, the air quality was bad, and what made it even worse, Gothamist is still battling a mysterious sickness he's had for almost a month now. While the temperature reached 91F, it sure as hell felt hotter than that. That would be due to the fact that the heat index was a lot higher (98F). Heat index is a measure of how hot it feels. When your body gets hot, sweating cools it through evaporation. But if the relative humidity is high, the evaporation process is slower, which in turn fails to cool your body effectively. Contrary to popular belief, temperature and humidity are not the only things that are used to calculate the heat index. Several other variables involved are set as implied values in order to make the calculation a bit simpler. Some of these more interesting variables include: dimensions of a human, clothing cover, sweating rate, effective radiation area of skin, effective wind speed, clothing resistance to heat transfer, and several others. Perhaps this can help explain why there is no true equation for heat index. Since the equation is simplified in this manner, using assumed values, it still remains only somewhat accurate.
Contact with a Bermuda High
Gothamist had the heat on at night last week when we were in central New York and northern Vermont so we were ill-prepared to return to the sauna of Manhattan. We have a Bermuda High to thank for the hot and sticky weather this week. The vigor of atmospheric circulation results from the temperature difference between the equator and poles. Temperatures near the equator stay relatively constant throughout the year. As the northern hemisphere heats up through spring and summer the equator-pole temperature difference decreases, and the atmosphere slows down. The pattern of atmospheric circulation is more complicated but is related to the strength of the circulation as well as the shape and positions of the continents and oceans.

