nav canada weather

by Greg
(Canada)

Cracking the Secret Code of the Skies - You can see how fast the wind is howling miles above your head by looking at a jumble of random numbers. Here's your chance to become a weather detective and unlock a secret language pilots and scientists use.

Greg says: How do I read an upper wind report from Nav Canada weather web site?

Barry's Response - Greg: Yeah, that's a good question. From what I understand, these are machine-generated tables that meteorologists don't need to use every day. I never finished the operational training, though.

Nav Canada upper‑wind basics.

Tables are sorted by station and assigned latitude and longitude ids. The next two lines in the left column indicate the forecast comes from the Canadian Meteorological Center in Montreal.

After that, it gives the date and Zulu time of the last input. "For use" indicates the Zulu hours for which the wind forecast is intended. There's a row at the top with elevations (when in doubt, assume ASL).

Here's the shakey part. It looks to me like a direction (2-digit) then speed (presumably knots like all other speeds on the site), since the group of four digits always starts with a pair ranging from 01 to 36. After that, there's a minus (and occasional plus) sign followed by another pair of digits, but not in the lowest column.

Could this value be a sign of shear? Maybe a standard deviation or gusting values. I wouldn't expect anything but shear at higher latitudes, but it's best to ask an air traffic controller, flight service specialist or experienced pilot.

Bottom line:

Ya got me! But I did a little more research.

Nav Canada upper‑wind tips

You may find it challenging to read an upper wind report from the Nav Canada weather website at first, but with a little practice, you will become familiar with the format and key information. Here's how to navigate the report:

- The upper wind report is under the aviation or pilot-specific section on the Nav Canada weather website. Look for a section called "Upper Winds" or "Upper Air."

- Identify the altitude: The upper wind report will give you specific altitudes, usually in flight levels or pressure levels (e.g., FL250 or 300mb). Find the altitude that's right for you.

- Wind direction and speed: The upper wind report will tell you the wind direction and speed at your altitude. Wind direction is given in degrees, showing where the wind is coming from. Knots are usually used to measure wind speed.

- The upper wind report may include temperature, dew point, and other atmospheric parameters in addition to wind information. They're useful for flight planning and assessing weather.

- Upper wind reports may include symbols and abbreviations that represent different meteorological elements. To understand these symbols and abbreviations, refer to the website's legend or key.

- Think about the validity period: Upper wind reports are usually valid for a certain period. Check the validity period of the report to make sure it's up-to-date.

- Don't be afraid to ask for help: If you're unsure about anything about reading the upper wind report, don't be afraid to ask experienced pilots, meteorologists, or aviation professionals. You can get valuable insights from them and understand the information better.

Search this site for more information now.

It takes practice and knowledge of aviation weather terminology to read upper wind reports. As you get more comfortable with these reports, you'll get better at interpreting them.

Want to go a little deeper?

Hodographs & Ekman basics

Hodographs and Ekman spirals are both meteorological concepts related to wind patterns. What they are and how a novice can find and use them:

- Hodographs are graphical representations of wind speed and direction at various altitudes. This shows how the wind changes with height. Hodographs are used in meteorology and aviation to analyze wind shear and storms.

You can find a hodograph on meteorological websites, research papers, or textbooks about atmospheric dynamics. The output of some weather models and forecasting tools may also include hodographs.

You need to know how to interpret a hodograph's shape and characteristics. Hodographs can tell you about wind speed, wind direction, wind shear, and severe weather potential. The best way to learn to read hodographs is to ask a meteorologist or study resources specifically about it. Check this Wikipedia article for an example: https://en.wikipedia.org/wiki/Hodograph

- The Ekman spiral describes the pattern of wind direction and speed in the ocean or lower atmosphere as depth increases. The Coriolis effect and frictional forces act on moving air or water to cause it.

You can learn about fluid dynamics and the Coriolis effect (where the wind pretends to curve to the right) from educational resources, textbooks, or online tutorials. Ekman spiral diagrams and visualizations can also be found on some meteorological and oceanographic websites.

Using the Ekman spiral concept, beginners can learn how wind patterns change with depth in the ocean or lower atmosphere. It helps explain how water and air masses mix vertically and the direction of surface currents. Oceanography, marine navigation, and atmospheric science can all benefit from understanding the Ekman spiral.

Wikipedia again to the rescue: https://en.wikipedia.org/wiki/Ekman_spiral

You can ignore the partial derivatives in the article and just look at the text and drawings if that suits you.
Both hodographs and the Ekman spiral are more advanced topics in meteorology and oceanography. To deepen your understanding and use of these concepts, consult reputable educational sources, talk to experts in the field, or take courses or tutorials.