From full autumn to golden October?

In the coming days, an autumnal weather pattern will spread across Germany, and with cool winds, rain and thunderstorms, the snow line will drop to the higher mountains, giving the possibility of sleet and night frost at lower elevations. But what about the golden October?

Hthe nature of the weather in the coming days is hereditary. Responsible for this is a low-pressure system that erodes from the Norwegian Sea towards Europe and, in addition to heavy clouds, can also lead to occasional showers, which over the higher mountains in snow pass over and over the lower elevations of sleet thunderstorm can be accompanied. Short periods of sunshine are possible between the showers and temperatures cool down to +10 to +15 degrees. In case of prolonged precipitation, the values ​​level off around +8 degrees and fall to +3 to +8 degrees at night. Clean it up, er ground and air frost possible.

Another weather change in October?

The layer over Germany, Austria and Switzerland will dissolve at the end of next week and make way for a wedge of the Azores. However, the location of the high pressure wedge will be crucial because the activity in the Atlantic frontal zone simultaneously increases and pushes towards Central Europe, leading to either a tend to maintain low weather patterns or lead to a weather reversal towards golden October. More on this in the current weather forecast for October 2022.

that Forecast of the European (left) and American (right) weather models: the outlook for early October could not be more different ©

The rain forecast

In the period up to September 30, repeated showers can be expected over Germany, which may focus on the coastal areas of the North Sea and the Baltic Sea as well as in the traffic jams in the Black Forest and the Alps. Tendentially less rainfall is possible over the northern low mountain range and the eastern parts of the country – there may also be areas that will not receive any raindrops at all.

The European rain forecast is on the left, the US forecast in the middle and the German forecast on the right: repeated showers and localized thunderstorms with different focal points are expected in the coming days
The European rain forecast is on the left, the US forecast in the middle and the German forecast on the right: repeated showers and localized thunderstorms with different focal points are expected in the coming days ©

Full autumn or Indian summer?

In the weather forecast for October, we have briefly explained the different interpretations of the weather forecast models for the first days of October and would like to take a closer look at the consequences for the further course of autumn, because the discrepancies are significant.

Conservation tendency with autumn weather character

that conservation propensity a few days ago we brought up in a thesis that the trough over Central Europe can be renewed again and again and thus ensure weather conditions that Full autumn with wind, rain and cool air masses get very close.

For a preservational bias to occur, the high must remain attached to the Atlantic Ocean and drive a wedge to the north. The Atlantic frontal zone is thus forced onto a northerly track and subsequently squeezed by the northward high-pressure wedge. This process can already be October 3 take place, which would inevitably result in a meridional north-south flow over Germany, Austria and Switzerland.

But how likely is such a preservation trend with daily values ​​of +7 to +12 degrees autumn temperature grade carries with him? In this case, the NAO index (simplified: the ratio between the Icelandic low and the Azores high) must first be positive and then negative. In fact, the NAO index shows positive on 1 October and turns slightly negative until 10 October.

On the other hand, the Europeans and also the Germans support theirs weather forecasts the conservation propensity. It makes you sit up and notice the possibility of one autumn conservation trend should be monitored further in the coming days.

The conservation slope with a meridional north-south flow
Forecast according to the European weather model: the maintenance slope with a meridional north-south flow ©

A step towards Golden October

We have also repeatedly explained in recent days how such a pattern can tilt in the opposite direction and an autumn weather situation for a late summer heat may follow.

So the weather in the direction Indian summer may change, it requires the help of a high pressure system which develops from the Azores towards Europe and strengthens over Central Europe during the first decade of October. If this succeeds, the advance of the Atlantic frontal zone will be blocked on the Atlantic and will let it dry out in the direction of the Azores. It is also one meridional basic flowexcept that this is due to an amplitude shift along the polar front warm air masses from southern directions to Germany, Switzerland and Austria.

How hot can it get? The Americans calculate such a weather situation and simulate daily values ​​that can make between +14 and +18 degrees and over the southwest up to +20 degrees possible on 3 October. On October 7, the temperature level will level out at +15 to +20 degrees and on October 9 at +16 to +21 degrees. With a decreasing precipitation activity and a increasing sunshine duration that fits the definition of a golden october.

The flip pattern towards golden October
Forecast according to the European (left) and American (right) weather model: the tipping pattern towards the golden October? ©

In a nutshell: Unstable and slightly too warm autumn weather

The Europeans literally bring fresh wind in the forecasts and are both decisive and with a holding tendency not unlikely, but the Europeans are currently showing the coldest development in relation to the control runs. Waiting is the order of the day.

After the onset of cold air, an increasing temperature trend

According to the average of all control runs, a temperature trend on September 30 is expected to be -3 to -5 degrees compared to the long-term average for 1961 and 1990 may be too cold. From 1 to 10 October, values ​​rise over the north to season typical and over the south, east and west with up to +2 degrees too hot level on.

The precipitation forecast for September 25 to 29 and October 1 to 3 allows the conclusion that the weather will be unstable. In the period 4 to 10 October, the precipitation signals return to the slightly elevated area, which means a golden october optional, but does not exclude a trough variant. This is shown more clearly in the mean value of all control runs.

Mixed weather pattern - neither a trough nor high pressure weather pattern
Forecast according to the average of all control runs: the trough weather pattern disappears at the beginning of October and turns into a mixed weather pattern ©

Mixed weather pattern – neither a trough nor high pressure weather pattern

The temperature forecast for the control is running
Day temperature spectrum average temperature
October 1st +10 more
+20 degrees
+14 more
+16 degrees
October 5 +11 more
+24 degrees
+15 more
+17 degrees
10 October +8 more
+23 degrees
+14 more
+16 degrees
Map temperatures October 2022
Probability of the October 2022 monitoring runs being too cold, normal, too warm compared to the long-term average (1961 to 1990)

The long-term model’s autumn and winter forecast

With a difference of +1 to +2 degrees, October should still be too hot. November and January can even be compared to the climate average for 1961 and 1990 with a difference of +1 to +2 degrees and in the trend up to +3 degrees significantly too hot stand out.

December and February saw a correction today, which is expected to be +1 to +2 degrees warmer than average (previously +0.0 to +1.0 degrees slightly too mild). The trend for February was even calculated up to +3 degrees too hot.

Eventually he can fall be +1 to +2 degrees (91/20: +0.5 to +1.5 degrees) too hot. Of winter shows a trend that is too warm with a deviation of +1 to +3 degrees (91/20: -0.2 to +1.8 degrees).

Too wet must be canceled September and February. October and January are simulated and tend to be a bit too wet, while November and December are simulated a bit too dry is accounted for.

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