Monday, November 16, 2009

Weather and planning for soaring

I wrote about this four years ago. I've changed my weather and planning routine, so here's an updated version.

For every day when I plan local soaring, I prepare by getting as much info as I can about the conditions. Here's what I usually look at. One or two days before:
  • If I am able to plan ahead, I check out general pressure patterns at the National Hydrometeorological Prediction Center at http://www.hpc.ncep.noaa.gov/basicwx/basicwx_wbg.php. Roll your mouse over each tab to get a decent moving display of the fronts. Otherwise I just keep an eye on the fronts and pressures from the TV news.
On the morning I'm planning to fly:
  • I start by looking at AOPA's Temporary Flight Restrictions and NOTAM page at http://www.aopa.org/whatsnew/notams.html. If there's a TFR due to firefighting or presidential movement, that's a show-stopper.

  • Weather Underground at http://www.wunderground.com/ includes a forecast of temps and winds by hour for the day. I write down the maximum forecast temperature for later use in my Thermal Forecast spreadsheet. This max temperature is usually the same as forecast by the National Weather Service.

  • Look again at the pressure patterns at the NCEP to see if anything's changed.

  • DUATS at http://www.duats.com/ to get several pieces of information: 1) synopsis for my region of the state, including forecast sky conditions for the day, 2) terminal forecasts for the two biggest fields closest to my home field, 3) look for any severe weather forecast, 4) temperatures aloft (which I write down for my Thermal Forecast spreadsheet), and 5) NOTAMs. Another major reason for using DUATS is that you have to log in with your Pilot's Certificate number, and they keep a record of it. If anything were to happen, I could prove that I got a DUATS weather briefing that day.

  • Get a SKEW-T plot from NOAA's RUC Analyses/Forecasts site. I use this to look for inversions and how they might change through the day. You can create bookmarks for the forecast for your favorite airports.

  • Next I plug the temperatures into my Thermal Forecast spreadsheet and print it one or more of the charts.

  • Finally, I look at the NWS's local soaring forecast at http://www.wrh.noaa.gov/sgx/data/aviation/soar.htm. I look at it last because I like to form my own opinion of the thermal tops and strengths, and then see if it agrees with this popular forecast. I print this and take it to the field to share.
This sounds like a lot, but it doesn't really take that long.

I used to look at the wind forecast using the ADDS Flight Path Tool from http://adds.aviationweather.gov but have got out of that habit. Now that I'll be flying at a site that can take advantage of ridge soaring, I might start checking it again.

2 comments:

Rob said...

No thoughts on XCSkies?

Roger said...

Good point. I have used XCSkies a few times, mostly when flying out of Tehachapi. It's great for giving a forecast across a wide area. After flying a couple of days, I went back to see how its forecast compared to what I actually found. One of the days, the thermal top forecast was right on the money.

At this point I don't do much cross-country. Since I don't own my own ship, and was busy with other goals this summer, I haven't purchased a subscription to it. It's overkill for local flying that stays within 10 miles of home... I did print it out a few times for Hemet. Like all forecast tools, it must use interpolation to come up with the forecasts for points between actual measurement sites. And there's a limit to the local resolution and accuracy of interpolation. So it's better for the big picture than for local flying.

Maybe if I get my Commercial and Instructor tests done this winter, I'll be more free to do XC out of Tehachapi or Warner Springs, and then I'll buy it.