Question

1. Suppose it’s warm and raining outside in Big Town. A cold front will pass Big Town in 3 hours. Behind the front, it is cold and snowing.
   1. Make a persistence forecast for Big Town, 6 hours from now.

2. Would you expect this forecast to be correct? Explain.

3. Now, make a forecast for Big Town using the steady-state forecasting method.

Answer 1

Suppose it’s warm weather……………..

1.            Make a persistence forecast for big town, 6 hours from now.

In general, you need to keep in mind that at the time of cold front, the temperature of a place can drop by more than 15 deg. so, if we define cold front, then in simple words, these are transition zones. So when this happens, cold air mass is being replaced with nearby hot air mass.

Second most important point about cold mass is that these are systems that move from NW to SE directions. So when a cold mass passes through any place or region, the air behind it is much lower in temperature.

The air that follows a cold front is also much drier and within the very first hour after the cold front asses a place, the temperature may fall down by as much as 15 Deg.

But it is also true that Cold front could be followed by warm front. So the weather is more likely expected to be more humid.

Now as it is big town and it is snowing and cold here, so I would expect the temperature to initially drop down by 15 Deg. by next hour. But as we are speaking of making weather prediction 6 hours from now, so we also expect the cold front to be replaced by warm front.

The weather should be warm and humid after 6 hours.

Would you expect this forecast to be correct? Explain

Based on the general pattern, the forecast is expected to be correct (in most cases). When speaking of the cold fronts, they mostly flow from SW towards NE. and these are also always followed by warm fronts. During the warm front passing stage, the temperature of the region will begin to rise. The surrounding air in that region would become warmer.

In between the cold front and the warm front, the atmospheric pressure also changes. But once the warm front passes by (which is expected as cold front would last for about an hour), the atmospheric pressure starts to get balanced.

But during this time you may also notice it starts drizzling, which may last for some time. This forecast is expected to be accurate.

Steady state forecast method

If we make weather predictions on the basis of past movement of the weather system, then it is generally termed as steady state method of weather prediction. As the name states the prediction is that the weather should remain steady or consistent.

So if the system has been moving with certain speed and in certain direction, then it will maintain its direction and speed. So as per this prediction, the temperature should be cold for specific time. But in most cases, this system of prediction is not considered reliable, as the weather systems may change at any movement. Weather in most cases is unpredictable. So if this system of prediction was true, then the weather should maintain cold front consistently.