Tonight, the strong convection in the south of the Yangtze River gradually organized into a huge squall line of thousands of kilometers, extending from northern Guangxi to Zhejiang. With the continuous emergence of strong convective clouds on the squall line, the southern part of the Yangtze River and the northern part of South China should be vigilant against thunderstorms, strong winds, hail and other fierce weather tonight and tomorrow morning, and many friends will even have to fall asleep in the thunder.
1. Sudden "typhoon" in Northeast China
If you open the satellite image today, you will be surprised to see that a huge cyclonic cloud system has appeared over the northeast, and it looks like a typhoon is making landfall. However, this is the northeast, and although it is not very far from the ocean, the latitude is already very high, so how can there be a typhoon? Don't worry, let me unveil the true face of this "typhoon" for you.
First of all, let's be clear that this cyclonic cloud system is not really a typhoon, but a weather system called an extratropical cyclone. Extratropical cyclone is a common atmospheric circulation system in the middle and high latitudes, and its formation and development are related to the fluctuation of the westerly wind belt, which simply means that the fluctuation of the westerly wind belt pushes the cold air to chase the warm air, thus forming a cyclone system. The direction of movement of an extratropical cyclone is generally from west to east, and it has a wide range of influences, which can bring changes in precipitation, wind, temperature, etc. to the areas along the way. On today's cloud map, it can be seen that the cyclonic system in the northeast of the mainland throws out rain bands to the south, thus driving precipitation and convective weather over the southern part of the country.
So, how did this extratropical cyclone in the northeast come about? It turned out that the formation of this extratropical cyclone was related to a cold vortex. The cold vortex is a kind of cold low-pressure circulation system existing in the middle and upper troposphere, and its central air temperature is significantly lower than that of the surrounding area, and the cold vortex is generally formed by the cutting off of the low-pressure trough in the westerly wind belt.
2. Local thunderstorms and heavy rains!
According to the analysis of the Central Meteorological Observatory, the extratropical cyclone in the northeast was induced by a cold vortex moving eastward and southward from Siberia in eastern Inner Mongolia. As the cold vortex moves eastward, it forms a cyclonic system near the surface. As the cold vortex continued to move eastward, the structure of the extratropical cyclone continued to evolve, eventually forming a complete cyclonic cloud system over the northeast that looked like a typhoon.
What is the impact of this extratropical cyclone on the Northeast? From last night to today, moderate to heavy rain has occurred in eastern Inner Mongolia and most of Heilongjiang, with localized heavy rain, which is the precipitation brought by the warm front of an extratropical cyclone. With the activity of extratropical cyclones, in addition to precipitation, there are also intense weather such as thunderstorms and high winds, which are weather brought about by the strong convection of cold vortices. These weather have brought adverse effects to local transportation, agriculture, life, etc., and have also brought inconvenience to people's travel.
Third, the culprit cold vortex is about to move eastward
Next, this extratropical cyclone will move further eastward, gradually moving out of the northeast of the mainland, with the eastward movement of the extratropical cyclone, the precipitation and strong convective weather in the northeast will also gradually weaken, but it is still necessary to pay attention to the local thunderstorms, strong winds, hail and other heavy precipitation weather.
The formation of the extratropical cyclone is related to the eastward and southward movement of the cold vortex. The cold vortex is a common weather system in the northern part of the mainland, which generally occurs at the turn of spring and summer and autumn and winter, bringing strong convective weather such as cold vortex thunderstorms to the northern region. However, this time the cold vortex began to move eastward and southward from Siberia in early May, which is relatively early. This may be related to the violent fluctuations of the westerly wind belt this year, which has led to frequent activity of cold air masses in the upper atmosphere, which has promoted the formation and movement of cold vortices.
The supercomputer's forecast pointed out that after the cold vortex, the situation of violent shocks in the westerly wind belt continues, and around May 14, there will be a cold vortex moving southward, which may still bring cooling, strong winds, thunderstorms and other weather phenomena to the northern part of the mainland. In short, the appearance of this extratropical cyclone in the northeast is a weather phenomenon worthy of attention, and its formation and development have certain laws and characteristics, and also indicate some weather changes in the future.