Weather “U” Lesson Nine Understanding The Upper Air Weather

Welcome back as we are now ready to take an adventure to the upper levels of the weather world. This lesson is long and focuses on the upper levels and how important they are to understand. Here we go.

In the first image above we see what is referred to as a basic upper air code. This code looks really crazy however once you break it down its not that hard. I will go over just the red numbers for this lecture.

63= Day of the month, well there is not 63 days in a month so this is where we have to do some basic math subtract 50. The reason this is done is for the purpose of covering every country that sends in wether reports. Some countries send there data in meters while the United States does knots. This way as you can see in the image aboe tells us which we are looking at.

12= The time in Zulu. Most stations do two obs a day one at 00Z and the other at 12Z. Some places may do more than 2.

01= This tells us that this balloon recieved wind data from 100mb in the sky. If the number was a 05 then we got wind data only up to 500mb and so on.

XXXXX= This will be filled in with a numerical value that is assigned by the WMO to each station. Each station will have a different number.

99= This is a standard number and will almost always be present as it repersents the indicator that we are lookin at the surface weather data.

015= These three digits repersent the Surface Pressure. In this example the surface pressure is 1015mb. If the surface pressure is lower the number will reflect such as if the surface pressure is 994mb the number will read just like that 994.

236= These next three digits repersent the surface temperature in degrees (C). We must place a decimal so that our number becomes 23.6C, here comes the trickey part how to tell if its a positive or negative number. If the number was 23.5C we would have a negative temp. That last digit is the key if its a (0,2,4,6,8) we have a positive temp and if its any other numbers its a negative temp.

05= These repersent the dewpoint depression. If this number is larger than 50 you must subtract 50 from it, then place a decimal behind the number so for example if the number was 55, we would subtract 50 and our new number is 5 so it tells us there is a 5 degree spread between the temp and dewpoint. This is very important in helping us identify cloud layers. “Rule of thumb” if the number is between 0-4 it is likely there are clouds or moisture present at that layer of the atmosphere.