Guide To Weather Map Symbols
Why do you, as an amateur weather observer, need a guide to weather map symbols? Why should you learn to read an interpret surface weather analysis maps?
As I will explain shortly, I believe that it is more than useful, it is "essential" that you to know where your weather observations fit in the current meteorological context, both before, and when you take them.
Note: To better understand how weather works, I recommend Meteorology: An Introduction to the Wonders of the Weather!
The Surface Analysis Map
Here is an example of what a surface analysis map looks like, in its most basic form. Click anywhere on the map to get the latest Surface Analysis Map (opens a new window).
Source: NAV Canada and Environment Canada.
Let’s start with the most elementary symbols of the guide to weather map symbols. The map above shows where high (H) and low (L) pressure centers were located at
, Tuesday March 13, 2007, as well as the position of the
air mass fronts
The somewhat lighter wiggly lines are called isobars. They join geographical locations having equal atmospheric mean sea level pressure values. They are like elevation lines on a topographical map, joining locations of equal elevation above mean sea level.
The first time one looks at this kind of map, it may just look like an incomprehensible mess of lines, and barely readable symbols.
Reading one of those just takes a little getting used to. Fortunately, with a guide to weather map symbols, and a little practice, you will be able to read, and use them to your advantage, just like a pro!
What's The Use?
First, knowing how to read a surface weather analysis helps you understand what you observe, and record.
But, the best part is that it also helps you brief yourself on the current meteorological situation. This prior knowledge helps you "anticipate" the weather that you will have at your site, at least in the short term.
To illustrate the usefulness of
present weather symbols
on the surface weather analysis map, and the need for guide to weather map symbols, here is description of a hypothetical, and interesting meteorological situation.
Following the analysis of plotted
weather station symbols
, let’s say that we find the following:
The 18:00 UTC Surface Analysis Map shows a
, just northwest of your region.
The map also shows some thunderstorm symbols, embedded in a narrow band of shower symbols, strung along the front.
You know, by having looked at the 12:00 UTC analysis, 6 hours earlier, that the front has moved closer.
Therefore, you can "anticipate", and "start looking out for", possible thunderstorm activity to occur at or near your observing site in the near future, as the cold front continues its progression southeastward toward you.
You can correlate the information you are reading off the map, with the forecast you heard on the radio or TV in the morning.
In the above scenario, you would be all set to report any thunderstorm activity, the moment it occurs near, or at your site.
Such "proactive" behavior
is the most important characteristic of a good weather observer.
Let me continue with the description, as the weather situation unfolds. You will soon see where a guide to weather map symbols fits in the scheme of things.
Observe, Record, And Report The Action
The first tell tale showers begin to occur. Some minutes later, you hear the first rumble of distant thunderstorms. Soon lightning is visible to the west.
The thunderstorms, kicked up by the approaching cold front, are getting nearer.
The sky gets noticeably darker. One thunderstorm cell triggers a heavy downpour of showers on your neighborhood. Small hailstones even bounce off the ground (and your car!) for a few minutes. The wind has picked up, and it is gusting strongly.
Some twenty minutes later … almost as suddenly as they began, the weather phenomena subside.
The showers diminish in intensity, and finally stop.
The thunder and lightning fade away to the east and southeast.
The clouds begin to part, and the sun is shining down.
Then … the wind, which was from the south by southwest before the thunderstorms … suddenly veers to westerly, then minutes later, to northwesterly.
The atmospheric pressure, which had been falling before the cold front, suddenly jumps, and begins to rise sharply.
The temperature rapidly drops a significant number of degrees.
The cold front has gone through ...
and you have witnessed, recorded, and reported all the action,
"blow by blow"
because you were there, ready for it!
The guide to weather map symbols helped you read the signs of impending weather off the surface analysis map!
You were actually "stalking" the cold front, and the thunderstorm activity.
As a weather observer enthusiast, you could have issued a "special" observation at each significant change of the weather situation at your site.
- First sign of lightning and thunder.
- Beginning of showers.
- Beginning of hail.
- End of hail (after waiting 15 minutes).
- End of showers (after waiting 15 minutes).
- End of thunder (after waiting 15 minutes).
- New situation: wind has veered, temperature is lower, pressure has risen.
Using the guide to weather map symbols, you would have been able to read the surface weather analysis map. You would have been prepared!
You could have shared your observations with other users of
You could even have helped the Environment Canada meteorologists on duty get additional information on the advancing cold front. They are always on the lookout for additional information. Always.
You could have helped make every other interested visitor of this Web site become better informed on the weather situation unfolding in your area … and, perhaps, soon to reach their region!
Part Of The Big Picture
The more reliable weather observations are made available, by weather observer enthusiasts like you, the better our collective understanding of the current meteorological situation can get.
The guide to weather map symbols, if you use it, can make you a better proactive weather observer.
With it, you can become one of the better prepared … and useful to your community!
Stay tuned, and keep a sharp weather watch!
For the only official World Weather Map, click here.
Return from this page on " A Guide To Weather Map Symbols "
Weather-in-Canada-Observer Home Page