The first part of our review is dedicated to the meteorological winter months at the beginning of year (1st of January - 28th of February).
High temperature anomalies: At the very first weeks of January, there were numerous reports of exceptionally high temperatures in many parts of the world. This can also be seen in our temperature anomaly map (see screenshot), where particularly huge parts of Europe and northern America show anomalies around +4°C for January 2023 compared to the reference period, which covers 30 years (1981 – 2010).
According to the WMO (World Meteorological Organization) many European countries faced temperatures above 20°C during New Year’s Eve, even resulting in some national or local temperature records for January. On the other hand, Iceland was confronted with unusually cold temperatures (negative anomaly) due to northerly winds bringing cold air masses towards the island, which also became visible on the map.
Heavy precipitation in California: A series of violent storms raged across the “sunshine-state” in early to mid-January. Over a period of 3 weeks, the storms caused heavy precipitation accompanied by hazardous super and multicell thunderstorms, resulting in major devastation and flooding. As we already reported back then, the precipitation coming from the storm series exceeded the average monthly amount for California after only a few days.
Our precipitation anomaly map shows deviations from the reference period for January 2023. Further, the monthly precipitation map indicates values up to almost 700mm. The largest amounts of precipitation could be recorded on the exposed west-face of the Sierra Nevada mountains. As another reference to understand a location’s typical climate conditions, you can consult the meteoblue climate diagrams, which are based on 30 years of hourly weather model simulations and are available for every place on Earth. Comparing the January values from the climate diagram (30 years average) with the actual amount of precipitation in January 2023, the following graph emerges for different locations in California, clearly showing the unusual high precipitation amounts for those locations.
Southern Hemisphere flooding and monsoon: A few weeks later (beginning of February), the southern hemisphere suffered partly from heavy rainfall events and floods. For instance, Auckland experienced over 240mm of rain in one single day. Flooding occurred within a very short time. Responsible was an atmospheric river from the Tasman Sea. These “rivers in the sky” are known for transporting a massive amount of water vapour from the tropics to extratropical regions. By reaching the landmass, the water vapour can be released in the form of rain. Besides New Zealand, other countries experienced the impact of the Monsoon.
The most significant precipitation events usually take place between December and May, which defines the rainy season due to the West African Monsoon. For further information, you are welcome to read our weather news about the rainy season in Madagascar.
Dry February in Europe: While there are numerous heavy rainfall events in southern Africa, large amounts of snow reached the Alpine regions at the beginning of February. However, the snow cover decreased quickly due to the subsequent mild weather in Europe. There, February is dry due to stable high-pressure situations. According to MetOffice (UK), England experienced the driest February in 30 years. The map shows the precipitation anomaly, which underlines the above-described observations.
Wildfires in Chile: Already in early February, wildfires have spread across central and southern Chile due to high temperatures and dry conditions in many regions of the country, as well as strong winds supporting the spread of the fires.
In the following reports of our four-part review of the year 2023, we will have a closer look at winter storms in the US, tropical cyclones, extratropical storms in Europe, and early heatwaves, and we will review the devastating wildfires in Canada as well as the El Nino development.
