So goes the landlubber's platitude, but it's not quite true.
     This week, people all over the country responded to weather forecasts as deserts were drenched and snow fell in states where people usually worry more about hurricane preparation.

     We may not be able to change the weather, but we can mitigate its effects on us.Land-dwellers may pay attention to the forecast, but probably don't give a second glance to the newspaper pictures of lows and highs.

     At sea, sailors and cruisers wouldn't dream of skipping the weather forecast for a couple of days. Some of us are obsessed with it, second-guessing storm tracks or chasing elusive low pressure systems in the middle of a high with nary a puff of air.

     We use it to determine navigation, which sails we might need, even what meals need cooking. We usually have a Single Sideband Radio aboard, along with a laptop that can download twice-daily grib files and weatherfaxes, those concentric blobs full of numbers, arrows, half circles and triangles. 

     If you're interested, here's an example of  what's coming across the north Pacific today, December 9, 2009.
  http://weather.noaa.gov/pub/fax/PPBE51.gif 

 Meteorology 101

     First, a quick review of how weather systems work. In the northern hemisphere, highs circulate clockwise and lows, counterclockwise. In the southern hemisphere, it's the opposite. The highest or lowest atmospheric pressure of the system is the number in the middle; a circled H or L helps you understand what you're looking at. Air pressure doesn't just instantly change from low to high. It changes gradually. Each of the rings around the system represents a band of equal pressure. 
 
     We use a barometer to gauge pressure changes, which we experience as wind. The closer together the bands are, the faster the pressure changes, bringing stronger winds. The outermost edges of a low typically have the most force, the strongest winds, like the last person in a line of "crack-the-whip."

     Remember, a low circulates counterclockwise. The huge storm that battered California on Monday (and has moved east) began with southerly winds on its leading edge, carrying warm, wet air. After its eye passed, the wind came from the north, bringing arctic air and frigid temperatures, as the tv weathercasters are so fond of saying.

     If you're looking at the fax link, you'll also notice feathered arrows that indicate wind direction and speed. The wind is coming from the direction of the feathers. The number of feathers indicates knots of wind: short feather = 5 knots, long = 10, and fat arrow = 50.

     Right now, that system looks frightful. At sea we would be planning as best we could for the worst-case scenario and hope that it veered a different direction. But we wouldn't know more than a couple of days ahead what to expect.

     All of this can be interpreted as, there's another monster storm a couple of days away that could be really bad.
 
     Unless it isn't.

     More on weather later.