1. Station Models!

2. What is it?
A station model is a symbolic illustration showing the weather occurring at a given reporting station (developed back in 1941) These reporting stations are EVERYWHERE; they are just simply locations with instruments and equipment for measuring atmospheric conditions

3. Why do we use them?
Easy to look at multiple weather elements in a small space on a map for multiple locations
Internationally accepted coding system for weather

4. What does a station Model cover?
A LOT of things
Temperature
Cloud Cover
Precipitation Type (amount)
Visibility
Pressure trend
Wind (direction & speed)
Dew Point (F)
Pressure at sea level

6. Cloud Cover Symbols
The circle in the middle depicts cloud cover. We look at it as a percentage. If it’s 25% cloud cover outside, you fill in ¼ of the circle

7. Visibility
Just tells you how far you can see out (in miles) before your gaze is obstructed by fog, precipitation, atmospheric elements, etc. *In this example, you can see clearly ½ a mile out

8. Current Weather
Current weather is depicted next to the visibility with a particular symbol (more on next slide) *In this example it says the current weather is snow (*). This would explain why you might now be able to see too far out, b/c its snowing

9. Current Weather Symbols

10. Current Weather
Also, if there happens to be no precipitation, then you do not put anything! Leave it blank!

11. Wind Direction Symbols
Wind is measured in knots, which is a speed equal to one nautical mile, approximately mph Each little marking is called a “feather” Little feather = 5 knots Big feather = 10 knots Bottom triangle = 50 knots

12. Wind Direction
Station model always describes where the wind is coming FROM *In this example, the feathered line tells me that the wind is COMING from the south east and GOING north west. Can you tell how fast the wind is going? 25 knots

13. Temperature on the model
ALWAYS in degrees Fahrenheit although we DO NOT include the units We want the simplest model possible so we just leave the unit (F) out. It’s assumed to be in degrees F

14. Dew Point
This is the temperature at which the air becomes saturated This is also ALWAYS going to be in degrees F, but we don’t include the unit F

15. How can we look at Humidity
Humidity on a station model is not explicitly put
You can INFER it by comparing the temperature and the dew point.
If the temp and dew point temp numbers are close together, it’s humid
If the temp and dew point temp numbers are far apart, it is less humid/not humid
This station model shows that it is very humid where it is

16. Precipitation
A station model is always going to tell the amount (in inches) of precipitation that has fallen in the past 6 hours *How much snow has fallen in this station model? ½ inch

17. Pressure
Pressure is the trickiest part of a station model!!! It is measured by a barometer, so it is called barometric pressure, the amount of pressure that the atmosphere is pushing down on the surface of the Earth This is measured in millibars or mb

18. Normal Pressure?
Typical pressure is going to range from about mb to about mb (this is what you will usually see) BUT these numbers are bulky on a weather station: mb - is bulky So we shorten it

19. Shortening how we show Pressure
Example: take mb
First, take away the units.
Then you get,
Second, drop the first number
The first number is ALWAYS either going to be a 10 or a 9. In our example, it is a 10. So drop the 10 and you get 14.0
- Third and last step, drop the decimal, and you get 140, this is what you write on your station model

20. Another Example to Shorten
Take mb
Drop units – 973.2
Drop first number (this time it’s a 9 and not a 10. *Remember, its always going to be a 9 or a 10 that you drop) – 73.2
Then drop the decimal – 732
732 is what you write on
your station model !!!

21. Convert the Pressure from the Model
When you’re given a model and you need to find the actual pressure, you have to convert it back from the shorten number. Take this example: 196

22. Convert 196 You’re taking the shortened version and lengthening it
FIRST RULE, determine if your number is lower or higher than 500.
If the number is less than 500, add a 10 in front of the number.
If the number is greater than 500, add a 9 in front of the number
** In this example we are adding a 10 in front because 196 is less than 500. So it becomes 10196

23. Convert 196 (cont.)
After you’ve added the 10 (remember we added the 10 in front instead of a 9 because 196 is less than 500) you have 10196
Add back your decimal, which ALWAYS goes ONE space BEFORE the last number:
Then add back your units mb
SOOOO, 196 is actually mb

24. Convert 675 (Example 2) So you see 675 on the station model
First step, is 675 greater or less than 500? Greater! So, add a 9 in front: 9675
Second step, add your decimal right before the last number: 967.5
Third and last step, add your units! mb
So, is the actual pressure that we got from the shortened version on the model

25. Pressure Trend
Right below the pressure on the station model, you will see a pressure trend. This tells us how much the pressure has gone UP or DOWN in the past 3 hours We WANT to know the trend b/c that tells us what sort of weather is headed our way. Pressure going down means bad weather is approaching. Pressure going up means good weather is approaching.

26. Pressure Trend Example
How do we read it?
This example says +19/
What that’s really telling us is that the pressure has gone up 1.9 mb in the past 3 hours (yes, you add a decimal before the last number)

27. Pressure Trend Example (cont.)
So, we know that the pressure in this example has gone up by 1.9 mb, but what does the + and / mean?
The + just means it is going UP. If it was a – then that would mean that it is going down.
The / just shows you that the trend is going up, like a mini graph line. If it was like this: \ that would mean it was going down.

28. Pressure Trend Example 2
Let’s say you measure your pressure trend at your station and the pressure has gone down 4.5 mb, how do you show this on your station model?? First, drop the units and decimal: 45 Then add a + or - …. It’s going down so: -45 Then add your trend, either / or \, we add \ because the trend is going down so we get: -45\

29. More Explanation?
This youtube video is great and explains what I just covered if you’d like to listen to it and gain a better understanding.