On July 22, the day of the Great Heat, my country's weather has already had strong summer characteristics: under the influence of stronger subtropical high pressure and continental high pressure, the warm sunshine covers many places in the north and south. Today's 35-degree high temperature coverage should be the largest so far this year. From Xinjiang to the southeast coast, nearly half of China's temperature will exceed 35 degrees. Only the plateau, mountains, northern Xinjiang, northeast China and the coastal areas of southern China affected by typhoons can be free from the heat. ​​​

1. -96 degrees cold ice cloud appears

At sea, the appearance of Typhoon Gemei and Typhoon Pabian also showed the characteristics of summer. The satellite cloud image on the morning of July 22 showed that Typhoon Gemei swallowed up the embryo of a small typhoon to its east, which brought two consequences. One was that it was overfed, had some indigestion, and its intensity developed slowly. The other was that it became a giant typhoon. Comparison on the satellite cloud image shows that although both are typhoons, Gemei is 5 times larger than Pabian, and the underlying gale circle may be more than 5 times larger.

In the early morning of July 22, Typhoon Geely 3, located east of the Philippines, showed amazing convective cloud characteristics. The cloud top temperature in the core convective zone reached about -96 degrees, which indicates that the internal convective activity is extremely strong. However, this strong convective cloud also has a certain complexity and is usually regarded as a weak state in the development of a typhoon, especially in many weak typhoons. This article will conduct an in-depth analysis of the phenomenon of Typhoon Geely, explain the background of its occurrence and future development trends.

Typhoon Gemei is currently showing unusually strong convective clouds. The cloud top temperature in the core area has reached around -96 degrees, indicating that the convective activity inside the typhoon is very intense. The intensity of convective activity is directly related to the cloud top temperature: the lower the cloud top temperature, the stronger the updraft and the more intense the convection. In the development of a typhoon, this extreme convective phenomenon usually means the presence of strong updrafts.

2. Typhoon Geely breaks through the tropopause!

However, although Typhoon Fengmei's convection is very strong, this state of extreme convection is often related to the development stage of the typhoon. The convective clouds of a typhoon may show strong convection in the early stages, but these characteristics do not always quickly transform into direct evidence of a strong or super typhoon. In many weak typhoons, the formation of extremely strong convective clouds with a central cold cloud cover is common, and this phenomenon is more common during the development of a typhoon.

The cold cloud cover at the center of Typhoon Fengmei is an important observation point. The formation of the cold cloud cover is closely related to the convective activity in the core area of ​​the typhoon. In the early stages of a typhoon, strong updrafts will push the cloud tops to extremely low temperatures, forming a cold cloud cover. This process usually indicates strong convective activity, but it may also cause the typhoon to temporarily appear in a weaker state due to the development stage of the typhoon itself and the influence of external environmental factors.

The cold cloud cover at the center of a typhoon not only reflects the intensity of convective activity, but may also be related to the environmental conditions that the typhoon embryo is in. For example, the abnormally high sea water temperature in the sea area where Typhoon Gemei is currently located, the abundant water vapor brought by the southwest monsoon, and the vertical wind shear all have an important impact on the convective activity of the typhoon.

Especially in terms of sea temperature, Typhoon Geely has extremely high sea temperature conditions. After comparison and confirmation, the sea temperature and ocean heat content in the sea east of the Bashi Channel, the sea east of Taiwan and the East my country Sea are the warmest in July since reliable data records began, exceeding that of Typhoon Nepartak in 2016. The extreme rise in sea temperature provides sufficient heat for convection, while the southwest monsoon brings abundant water vapor, which together promote the formation and development of convection.

Although the convective activity of Typhoon Fengmei is very strong, the vertical wind shear still interferes with the development of the typhoon to a certain extent. Vertical wind shear refers to the difference in wind speed and direction at different altitudes, which will affect the structure and development of the typhoon. Current supercomputer forecasts show that the vertical wind shear in the area where Typhoon Fengmei is located has interfered with its development to a certain extent. This makes the updraft of Typhoon Fengmei strong, but ice crystals accumulate on the top layer after the updraft, and the outflow channel to the surroundings is blocked. Therefore, the cloud top temperature is very low, but it has not yet fully demonstrated its potential strength.

As Typhoon Geely gradually turns to the northwest, the impact of vertical wind shear on its development is expected to weaken. In the process of moving northwest, the typhoon may encounter more favorable environmental conditions, especially when the subtropical high pressure gradually guides the typhoon to approach the eastern coast of my country. This process may be conducive to the further strengthening of the typhoon. For example, the Central Meteorological Observatory forecast shows that it will gradually strengthen to a strong typhoon intensity of 14 to 15 in the future, and may strengthen to the lower limit of a super typhoon.

Looking ahead, the strengthening trend of Typhoon Fengmi deserves attention. According to current forecast data, as it moves northwest, it is possible that Fengmi will further accelerate its strengthening speed and reach the level of a typhoon or a strong typhoon, and may even become the first super typhoon this summer. However, there is still great uncertainty about the final path of Typhoon Fengmi.

For example, the Central Meteorological Observatory's forecast pointed out that Typhoon Fengmi may land on my country's eastern coast from the evening of July 25 to the early morning of July 26, but the supercomputer weather forecast believes that the typhoon may pass through northern Taiwan and land in Zhejiang, or may land in Taiwan and Fujian successively. This forecast still has certain variables, and we need to continue to pay attention to the latest weather developments.

Typhoon Geomei's current extreme convective clouds and cloud top temperature of -96 degrees highlight the intensity of its internal convective activity. Nevertheless, this strong convection does not necessarily directly indicate the intensity of a typhoon in its early stages of development, and will be affected by a combination of environmental factors. There is still great uncertainty about the speed and path of Typhoon Geomei's strengthening in the future, and we need to continue to pay attention to the latest weather forecasts and dynamics.