Monday, November 15, 2010

Something for Everyone



Several months ago, the Earth-bound Misfit shared a link that I have found very useful -- for aviation and photography. We all know that aviation is ruled by weather. To a large extent, so is photography. At least outdoor photography.

I think most of the aviation crowd can handle the nomenclature on this web site but let me say a few words about it for the photography folks. First, let’s take a look at the site.

CWSU National Map



This is the Center Weather Service Unit map of the United States. The “Center” is an Air Route Traffic Control Center (ARTCC) like the one I used to work in. Each Center has its own staff of National Weather Service people -- the Center Weather Service Unit. The map is an interactive map and various text boxes will pop up as you move your cursor around the map. Here’s how I use it.

First, I get it down to a useful scale. At the top of the page you’ll see the “Select ARTCC Map” button. I use “ATL” for the Atlanta Area. Currently, it’s O’dark-thirty and I’m wondering if there will be a decent sunrise this morning. You can’t tell much about the sky at night. It’s either clouds or stars. Currently it’s clouds. But what kind of clouds? That’s where this site comes in handy.

If you’ll roll your cursor over an airport symbol, the National Weather Service will tell you about the clouds. The closest airport to me (with a weather station) is Falcon Field (FFC) in Peachtree City (a suburb south of Atlanta.) Here’s where it gets tough for the non-aviation folks. You have to be able to read the code.

You get the name, elevation, temperature dewpoint and relative humidity at the top of the pop-up box. Next is:

Visibility -- 4.00 (miles)
Weather -- BR (that stands for Mist)
Clouds -- FEW024BKN041OVC055 (that’s the tough part)
Altimeter -- (I don’t think photographers care)
1 hr Precip -- 0.03 (how much rain in inches)

To decode a weather report like this, you can refer to this site. It will tell you that SN is snow, BR is Mist, HZ is haze and all sorts of things you don’t want to know (like VA is Volcanic Ash.) I want to concentrate on the cloud section. FEW is simple -- few. Less than 2/8ths of the sky is covered by this cloud layer. And that is what the numbers are about. It tell you the altitude (or height) of the clouds.

FEW024BKN041OVC055

There are a few clouds at 2,400 feet, a “broken” layer at 4,100 feet and an “overcast” layer at 5,500 feet. You can read about it in more detail at the same site as linked above but that is probably all you need to know for photography purposes.

To sum it up, to the north it’s raining and there are a lot of low clouds. It doesn’t sound like much of a photography morning. But to the south and southeast, Thomaston (OPN) is reporting 10 miles visibility with 8,500 overcast and Macon (MCN) has 10,000 foot overcast. I wonder if that’s high enough for the Sun to sneak under and light up the clouds? You’ll never know unless you show up.

By the way, take notice that the pop-up boxes also give you the local sunrise time at the bottom of the box. It’s really nice to have all that info when you’re on the road, photographing a different area.

Don Brown
November 15, 2010

No comments: