Summer is in full swing, but weather forecasters from the Institute of Meteorology and Water Management tried to predict the weather in the second half of this season and in the fall, i.e. from August to November. See what the meteorological models show.
The Institute of Meteorology and Water Management – National Research Institute (IMWM-PIB) has released long-term forecasts for the period from August to November, which it describes as “experimental”. For calculations, experts use their own IMGW-Reg and IMGW-Bayes models. They also use results from the US National Oceanic and Atmospheric Administration (NOAA) and European Center for Medium-Range Weather Forecasting (ECMWF) models.
Will August be hot?
According to the IMGW, the average monthly air temperature in August in Poland from 1991-2020 should be above the long-term standard. As for precipitation, their sum will most likely fall within the long-term norm.
The beginning of autumn. What’s the weather like?
According to the calculations of weather forecasters, the average monthly temperature in September in Poland should be within the long-term norm of 1991-2020 or slightly higher. On the other hand, the sum of atmospheric precipitation in most of the country should be within the range of the long-term standard. Only in the northeast can it fall above the norm.
Temperature and rainfall in October
According to IMGW, the average monthly air temperature across the country in October should be within the range of the long-term standard of 1991-2020. The sum of atmospheric precipitation at that time in most of Poland is also expected to fall within the long-term standard. Only in the northwest is an amount above the standard possible.
Aura in November
According to the models, both the average monthly air temperature and the monthly sum of precipitation across the country should be within the range of the long-term standard of 1991-2020.
See the full long-term forecast for August to November 2022 >>>
What do the terms “above normal”, “below normal” and “normal” mean?
In the IMWM-NRI, as in other meteorological centers around the world, the average monthly temperature / total rainfall for a given month is forecast in relation to the so-called long-term standard. The period 1991-2010 is currently being looked at.
The values of the average monthly temperature or monthly precipitation sum for this period are sorted from low to high. The 10 lowest values represent the temperature/precipitation class “below normal”, the middle 10 “normal”, and the highest 10 – “above normal”.
If we are dealing with an “Above Normal” class, we can assume that the month will be warmer or wetter than at least the 20 observed same months in 1991-2020. If it is predicted to be “below normal”, it will be cooler or drier and “normal” – similar to the 10-month averages of the comparative period.
How to interpret classes?
IMWM weather forecasters are raising awareness that the forecast of the average air temperature “above the norm” does not mean that there will only be days with the maximum temperature above 25 degrees Celsius, and the forecast “below the norm” – that there will only be days with the minimum temperature below 5 ° C. C – in fact, the forecast of the average temperature “below normal” does not exclude the occurrence of days with the maximum temperature above 25 ° C, and the forecast “above normal” – days with the minimum temperature below the 5 degrees C.
Experts note that it should be remembered that the forecast average temperature refers to the average temperature for the whole month, to the temperature recorded both during the day and at night.
Also, the forecast of total precipitation “above normal” does not mean that only intense rainfall and storms will occur, and the forecast “below normal” does not rule out the possibility of such phenomena. The expected precipitation sum refers to the sum of precipitation for all days of the month. The type of precipitation (snow or rain) is not specified in the forecasts
Verifiability of long-term forecasts
As emphasized in its communication by IMGW, despite the increasing computing power of supercomputers and extensive knowledge about weather processes, errors and differences in forecasts for such a long period of time in the future are unavoidable. The discrepancies result from both the risk of sudden (often local) meteorological phenomena, which can disrupt predicted weather processes, and the huge variety of physical assumptions used in forecasting models, as well as mathematical and statistical equations.
It is not possible to describe the weather forecast in more detail that far in advance. It should be remembered that the forecast is indicative and its character is experimental, and it concerns the average mileage for the entire forecast area and a particular forecast period – writes IMGW.
Main photo source: Shutterstock, IMGW