Weather: Waiting for heat wave

The weather will be good for the weekend without any problems Progress from late afternoon, with local effects in the northeast on Saturday. Northerly winds will be 4 to 6 and inland 7 Beaufort seas and temperatures will drop slightly in the north where it will be 32 to 33 degrees Celsius and 35 to 36 degrees Celsius in other parts of the mainland. Islands 31 with 34.

There will be a slight increase on Monday and Tuesday, but not significant. In the video below, see temperature levels and risk levels through next Thursday, which are relatively mild.

Blocked by the northerly current in the lower levels of the atmosphere, the warm masses off the coast of Africa will not be able to move towards our region until next Tuesday.

However, from Wednesday, the flow of gas masses changes to the southwest, which means practically From Wednesday to Thursday the warm masses are “released” and expand further east.

Southwesterly circulation prevails but downward movements of the atmosphere They can cause a significant rise in temperature with values ​​reaching heat wave levels.

A little lesson in meteorology

The map we used above is the 850 hPa map and it gives the values ​​for Thursday and the prevailing temperature range at that level covering much of the Northwest along the 24°C isotherm curve. , located on the Ionian and northwestern mainland.

This practically gives us a surface temperature of the order of 24+15(17)=39(41) degrees. We have developed in the previous article. Generally, we set maximum temperature of 39 to 41 degree Celsius as representative value for next Thursday for continental parts of our country.

To make it easier to understand the flow of the atmosphere, we quote the following video by tweet.

On the issue of time There is no clear data yet, but we estimate that the situation will improve in a few days. With today’s data The heat wave is likely to last for more than a week. We will review the situation in the coming days from EMY and by early next week, we will be able to update you on the duration and intensity of the heat wave.

As we mentioned earlier, the main reason for the high temperature in our country is the transfer of hot gas masses from the coast of Africa from the region where there is no high temperature. That’s why we need to be more careful.

At the lower levels of the atmosphere, (850 mb – approximately 1500 meters, the southwest wind blows, this phenomenon is observed when the high pressures at the upper levels (500 mb) cause landslides of gas masses. Add more heat to the lower layers.

Here we have to note that as a rule, in our country, emergency notifications of National Meteorological Service (EMY) are issued when the maximum temperature is predicted to be above 40 degrees Celsius. One day and We classify events of high temperature as “heat” when the following criteria are combined:

1. Maximum temperature greater than or equal to 39°C at compact or aeronautical weather stations.
2. The minimum temperature is a high of 26 degrees Celsius.
3. Breathless or light winds prevail and the temperature range is small.
4. High temperatures are observed over a wide geographical area and their duration is more than three days.

The Worst heat wave in decades From July 19 to 27, 1987, the mercury exceeded 39 degrees in many areas and there were eight days at the highest values ​​with a small daily temperature range. proportionate “Hot Episode” This was repeated in early July 1988, with long periods of hot days.

Although maximum temperatures are usually observed in the third decade of July, some areas such as Attica saw an even higher value of 45 degrees in late June 1982 and in the first decade of July, 10.7 in Tatoi and 48 degrees in Eleusis. The 1977 values ​​were rejected by a section of the scientific community.

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