Morse Code of Weather: how wind direction influences when we warm up and airport runway orientation
BISMARCK, N.D. (KFYR) - Sometimes the wind can be a good thing, as when it’s blowing in the right direction it can help to warm us up! And the direction that the wind is blowing from not only influences our temperatures and weather patterns, but also plays a role in airport design.
Meteorologists use all sorts of different graphs to display data, but a really interesting one is a wind rose. It’s somewhat a combination between a pie chart and a bar graph as it combines three separate variables into one plot: wind speed, wind direction, and the frequency of the wind speed/direction.
The wind rose for Bismarck is shown below, taking into account the wind speed and direction at the Bismarck airport since 1970. As it plots the wind speed and direction over time, distinct peaks show up on the chart. The largest one is on the northwest side of the compass. This means that the majority of the time at the Bismarck airport, the wind is blowing out of the northwest. And a large amount of the darker colors in this direction also indicates that the wind is pretty strong when it’s blowing from the northwest.
A second peak shows up in the south-southeast and then a smaller third peak in the east-northeast. So these wind directions are also fairly common in Bismarck.
These prevailing, or predominant, wind directions also hold true for most other locations in North Dakota.
When airports are built, they usually take into consideration these prevailing winds so that airplanes have the easiest time taking off and landing. Below is a satellite image of the Bismarck airport and the main runway is set up in a northwest-southeast orientation, which corresponds to the wind directions that occur in Bismarck most frequently. Pilots want to land into a headwind to help slow the plane down as the wind is blowing in the opposite direction that the plane is landing in. The same is true for takeoffs, as a headwind helps to generate greater lift and they will take off sooner compared to trying to lift off in a tailwind. And a crosswind is not favorable for taking off or landing as it can tip the plane side-to-side.
Therefore, with a northwest-southeast-oriented runway, planes usually have the option to take off and land into the headwind as the Bismarck wind rose shows that the wind is usually blowing from the northwest or south-southeast directions.
In terms of how the wind direction plays a role in when we warm up, check out the wind rose below that shows the wind speed, direction, and frequency in Bismarck when temperatures are above 70 degrees. The predominant wind direction when these temperatures are occurring is out of the south-southeast. Therefore, when a south or southeast wind is in the forecast, it usually means that we’re warming up. This makes sense with warmer weather usually down to our south, and the winds help to transport these warmer temperatures into our area. This is also true for moisture, as with south and southeast winds we can see humidity levels increase thanks to the Gulf of Mexico being down to our south-southeast. These elevated humidity levels with a south-southeast wind can help to fire up thunderstorms in our area.
The same is true for just the month of May, as the peak in the wind rose is clearly to the south-southeast.
The opposite is usually true when we see a cool down in the winter. The wind rose below shows wind speed, direction, and frequency during the winter months (December, January, and February) when the temperature is below 32 degrees. You can see that the predominant wind direction is out of the northwest. Therefore, our cooldowns and Arctic outbreaks usually feature a strong northwesterly wind delivering that chilly air from Canada.
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