Archives for posts with tag: air masses

Another day, another polar vortex.  It seems that the atmosphere has reached down from the northernmost region of the earth and trailed a frigid finger of arctic air across the exposed back of the northeast.

To say that it has given us the chills would be a gross understatement; the temperature was two degrees below zero this morning.  This winter is on track to become the coldest one of my life.

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Just before shutting down my computer this evening, I took one last look at the weather forecast.  Some people compulsively check the stock market and others keep close track of baseball (and other sports) scores.  I’m addicted to the weather.

I was rudely surprised to see that the National Weather Service had posted a Frost Advisory for later tonight and into tomorrow morning.  Where did this come from?  Yes, the forecast has been calling for cooler temperatures, with highs in the 70s and lows in the 40s and 50s, but frost?  Really?

And what am I supposed to do with this information, at such a late hour?  The warning was not posted until about 6:00 pm.  That gives me only an hour before the sun sets.

Not that more warning would have been particularly useful.  Although the number of plants remaining in the garden is diminishing, there are still several growing strong.  And all of them are either tall (e.g., the tomatoes and string beans) or spread out (the squashes).  It’s not like I can easily throw a tarp over the entire yard.  (Well, I suppose could do that, but it wouldn’t be easy.)

I imagine that some farmers will be firing up their smudge pots tonight.  A common sight in orchards and vineyards, these oil-burning heaters produce a high-volume of slow-rising smoke—some call it artificial smog—which I always thought enveloped the plants and slowed their cooling.

Turns out they work more like the large fans that other growers—such as an apple orchard we visited last weekend—will be switching on instead.  Both the heaters and the fans circulate the lower levels of the atmosphere, moving colder air at the surface upwards and bringing down warmer air from the overlying inversion layer.

I love the idea of having one of the monster fans in my backyard (I could connect it to my propane tank) but I suspect they are very expensive (no, I’m not seriously considering it).  So this time, we’ll take our chances and do nothing.  Despite the advisory, the forecast low is 44 degrees, well above freezing.  I’m not too worried but we’ll see how things look in the morning.

The middle of last week, 90 percent of the computer simulations reported by the Weather Channel predicted that Hurricane Sandy would drift off into the Atlantic after wreaking havoc on Cuba, the Bahamas and Bermuda.  Only one or two models indicated a trajectory over the mid-Atlantic coast of the United States.

By the weekend, all of that changed.  Apparently, a region of high pressure in the north Atlantic was blocking the normal eastward path of the hurricane.  To make matters worse, a mass of cold air descending from Canada and the Ohio Valley was threatening to combine with Sandy to create a storm—a la Groundhog Day—of epic proportions.  The pressure systems were bumpers and Hurricane Sandy a steel pinball in the giant arcade game that is the earth’s atmosphere.

Consequently, the National Weather Service is now predicting the end of the world.  Well, not quite but the forecast is very dire.  The expected storm could be like last year’s Hurricane Irene and October snowstorm combined, a rainy, snowy, windy mess.  The pressure at the center of the storm is extraordinarily low and when combined with tonight’s full moon, will result in record-setting tidal surges along the coastline.  We’ve been warned to prepare for the worst Mother Nature has to offer.

So now we are waiting for Sandy to arrive, with an emphasis on the waiting.  This storm is moving slowly—only about 15 miles per hour—leaving us to agonize in anticipation of its potentially dire impacts.