Station Models and Converting Station Pressure into Millibars

Synoptic Weather MapsSynoptic weather maps: Show atmospheric

quantities like temperature, air pressure, precipitation and other weather conditions at a particular time and over a large geographic area

Synoptic weather maps can be used to make weather predictions

Why?Station models and pressure are key components

for making an accurate forecast-For example, if you are making a forecast for the New York Yankees and you say, “There is a 20% chance of rain” but it is already raining, you probably won’t be forecasting for the New York Yankees for much longer!

At least 1 question on the Regents is about station models and at least one question on the Regents asks you to convert station model data to millibars

Station ModelsUsed on weather maps to show the current

weather conditions for a particular locationThey are easy to read and understand

Page 13 of your Reference Tables

Cloud Cover and WindsThe circle at the center shows the amount of

cloud coverThe “flag pole” coming out of the circle

shows the direction that the wind is coming from

Each “flag” shows approximate wind speed. A half flag shows an approx. 5 knot wind, and a whole flag shows an approx. 10 knot wind

*Add up the amount for each flag for the total wind speed

1 knot = 1.15 mi/hr

Determining Air PressureAir pressure is shown by using the last 3 digits of

the pressure in millibars (coded)Ex. 1018.6mb = 186 on the station model

To determine the air pressure from the numbers on the station model, use the following rule: If the first number is 5 or less, put a 10 in front

of itIf the first number is 6 or higher, put a 9 in

front of itPut the decimal point between the last two

numbers

ExampleThe air pressure on a station model is 892.

What is the pressure in millibars?ASK YOURSELF….Is the first number 5 or less?After you add the number in front of 892,

where does the decimal go?

**Remember, surface air pressure is usually between 960mb – 1050mb

If your answer is not in this range, then it is wrong. Check your work!

Another ExampleWhat is the pressure of this station in

millibars?

Practice with Station ModelsTake two minutes to use your Reference

Tables and the information below, draw the station model of Slate Hill. Compare your answer with your neighbor.

Slate Hill Observations: Cloudy, 61*F, 58* DP, 8.0 mile visibility, pressure is 996.0 mb, wind speed 9 mph, from SW.

Your station model should look something like this…

How about decoding station models?Take the next few minutes to write down the

weather information that is given by the station model below.

You should be able to answer the following questions: What is the temperature? What is the dewpoint? What is the pressure in millibars? How much precipitation fell in the past 6 hours? What is the visibility? What is the present weather?

Example Regents Questions1. A weather station model is shown below.

What is the barometric pressure indicated by this station model?

(1) 0.029 mb (2) 902.9 mb (3) 1002.9 mb (4) 1029.0 mb

2. Which station model shows the correct form for indicating a northwest wind at 25 knots and an air pressure of 1023.7 mb?

RADARRadar: reflects radio electromagnetic energy

off the aerosols of precipitation and clouds. Radar provides a tool accurate short-range

prediction, showing precipitation intensity, precipitation type, and where it is heading.

AccuWeather Radar