I have always found that
Meteorology is a totally exciting affair. Especially in the mountains, it can be very crucial to be able to use a few signs to make an approximate forecast of what the weather will be like in the future. Especially in the height of summer, when the muggy air gives rise to more frequent thunderstorms and heavy rain showers. Within half an hour the previously still blue sky can be covered with massive thunderclouds. A strong wind sweeps the last thoughts of the initially so beautiful sunny day down into the valley. Short time later the first lightnings twitch over the sky. Are accompanied by resounding thunder threatening.
In the mountains, a thunderstorm like this is a damn unpleasant and dangerous thing, as I was able to observe last year in Trentino. With a little knowledge of meteorology, you can spot thunderstorms or deteriorating weather fortunately Relatively reliable forecasting with simple tools.
At Day tours you can inform yourself well with the available reports at the alpine association whether rain, storm or sunshine is to be expected. At tours lasting several days without access to a daily updated weather report, however, it can be very helpful to make your own small forecast.
Unfortunately, I never had the expertise to use the current weather information to tell whether it will rain today or whether the fog is likely to clear and the sun will come out. Therefore I did some research and tried to find a few to put together some hints, by which you can tell if the weather is going to deteriorate or not.
But before that a little bit of theory behind the meteorology:
The atmospheric prere in meteorology
In the assessment of the weather situation and its development, air prere is a decisive and measurable variable. It briefly describes the weight of air. The higher we climb, the less this weight and thus the air prere becomes. We can measure the air prere with a barometer in hPA (hectoPascal), which is integrated in some wrist watches as an altimeter. The values are always around the mean atmospheric prere of 1013.25 hPa, which is approximately 1 bar 3 .
In most cases Fair weather rising atmospheric prere and in case of bad weather falling air prere. But also the speed of the increase resp. Falling off to be considered. But more about this later. lines of equal prere) are shown. Is one of the most important elements of these maps.
High and low prere areas
High and low prere areas are air prere formations whose air prere differs significantly from their surroundings. The two variants exist in constant neighborhood 1 . During a High prere area large air masses descend and warm up so much that condensation and cloud formation do not occur. Therefore, in an area of high prere or a high mostly sunny weather occurs. Warming up humid air from the ground. Forms clouds in the colder heights by condensation. Thus, an area of low prere tends to represent cloudy and rainy weather.
Now the following 8 signs are very helpful in making your own weather forecast to determine if weather deterioration will occur. Nevertheless, they are not a 100% guarantee. Because even the best weather forecast can be off once.
In any case, it is always helpful to watch the weather closely and see if the detected signs actually correctly forecast a deterioration of the weather.
Meteorology: tips on how to recognize bad weather:
1. change of air prere
Many signs in the nature, which point to a weather worsening, one must also meet, in order to be able to interpret them. With the atmospheric prere, of course, the whole thing looks different. We can measure it at any time with a barometer. Observe the changes over a period of time. For an approximate weather forecast, the change in atmospheric prere is a helpful parameter, as this change usually precedes the weather change.
A weather deterioration usually announces itself when the air prere drops. As mentioned above, it is important how fast the air prere decreases. A steady and slow decrease indicates the end of a period of good weather 2 .
In principle: The faster resp. the stronger the drop in air prere, the more violently the weather deteriorates. If the atmospheric prere drops by more than 1 to 2 hPA in one hour, then storms and violent winds are to be expected 3 .
Determining air prere with the altimeter
In the some Watches for outdoor use*, an altimeter is integrated, which works through a barometer. This barometer measures the current air prere and uses it to calculate the probable altitude above sea level, since air prere decreases with increasing altitude.
This means that in falling air prere the altitude indication rises. The opposite is true for rising atmospheric prere, which is reflected in a falling altitude Results. Therefore, as we ascend and descend, the change in barometric prere cannot be meaningfully determined, since it is already changing anyway due to our change in altitude.
A meaningful measurement can therefore only be made if you stay at the same altitude for a long time. How z.B. at the hut or at the camp site in the tent.
The determination of the change in air prere is therefore one of the best ways to detect a weather change!
2. Cirrus clouds can herald rain
Cirrus clouds (cirrus clouds) are ice clouds that form at very high altitudes (8.000 – 12.000 meters). They are often harbingers of a coming warm front when they condense into cirrostratus fields (veil clouds). In this case a lasting weather deterioration occurs in the following 48 hours 1 .
If they are seen in the sky only sporadically and dissolve again, we do not have to fear a deterioration of the weather.