Soaring Forecast Tools
Quick Links to Soaring Forecast Tools
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SOARING FORECAST TUTORIAL
The goal of this tutorial is to offer a set of tools to forecast soaring conditions for our local Hood River Valley and mid-Columbia region. The above links are to websites that will help you forecast a good soaring day. Combining information from multiple sources gets the best results.
For a long range overview, a good starting point is the the National Weather Service (NOAA) 7 day forecast for Hood River shown in the example below. Soaring conditions are often best the day or two before a weather system and a day or two after, so look for that pattern in the forecast. Check cloud cover; 65% or less is good. In the drier months the clouds usually stay clear of the ridge. Check the wind; a west wind of 10-15 knots is a good sign. The snow level tells you how to prepare for temps aloft.
The image below is a sample forecast shown for illustration purposes. The highlighted sections all have good soaring potential, especially Saturday, Monday, and Friday because of weather system changes. Click anywhere on the image to open the live NOAA site for the current forecast.
To drill down on more precise information about lift conditions, use the NOAA Soaring Forecast. Scroll down the page to find the listing for Hood River; then click the link for the forecast in the "today" or "tomorrow" column. The forecast shows the THERMAL INDEX (TI), TEMPERATURE of CONVECTION (TOC) and the strength of POTENTIAL LIFT at varying altitudes. A TI of -3 or lower indicates lift at the designated altitude. The forecast also provides data for winds aloft. A 10 knot westerly flow at 3000 ft plus a TI of -3 or lower means the ridge will likely be working. The higher the thermal boundary indicated by -3 TI, the higher you can climb at the ridge.
The Windytv site embedded below offers a big picture of wind conditions for our region. The surface winds for today are shown. Use the forecast slider at the bottom to scan up to 10 days ahead. Click on the wind symbol at top/right, and then use the altitude slider to see how wind prediction varies by altitude. Click on the low, med, and high cloud views to see how you might exploit the winds aloft. For more features, click here: Windytv Map & Weather Forecast to open the full site.
The height of the thermal boundary layer will determine how high you can climb in unstable air. However, if the jet stream is overhead you may find wave, which will enable you to climb much higher. Click on the image below to view an animated 5 day jet stream forecast. When the jet stream is directly overhead and the air above the thermal boundary layer is fairly stable, there may be wave. If the jet stream is too strong however, the wave does not work well.
The site embedded below is a sounding plot for this region and is the current forecast. It is best viewed on a desktop computer. Mobile viewers, click WxLoop Hood River to open the plot in a new window. The sounding plot provides a wealth of information about thermal activity, cloud development, winds aloft, how high you can expect to climb, and the potential for wave. Learning how to interpret the sounding plot is a challenging but very worthwhile commitment for glider pilots. While a comprehensive tutorial is beyond the scope of this page, here is a brief guide to reading the chart:
The background graph is formed of static lines: black, green, red, and purple. The horizontal black lines represent different atmospheric pressure levels measured in millibars (mb). Pressure altitude varies but can be roughly viewed as 900MB ~ 2,500', 800MB ~ 5,000', 700MB ~ 10,000', and 500MB ~ 18,000'. The vertical black lines represent temperature gradients in centigrade ranging from -50 to 40 degrees.
Animated on the background graph are two bold lines, one red and one blue. The blue line represents the dew point of the atmosphere at different levels. The red line represents the environmental air temperature. Both the red and blue lines originate at ground level. Ascending into the atmosphere, if the angle of the environmental air temperature (red line) parallels or leans left of the dry adiabatic lapse rate (green line), that indicates good to better thermal lift. When the red line angles to the right, that indicates stable air, which is an absence of thermal lift, but when combined with the right wind speed and direction it may produce wave.
Wind barbs in the far right column show wind speed and direction.