How do meteorologists predict the recent weather conditions as soon as possible before the launch of Shenzhou IV?

After receiving the order, meteorologist Pan Zhibin and his comrades-in-arms made a detailed inspection of the meteorological data of the center for more than 30 years, and finally came to the conclusion that the strong vortex system would bring a heavy snowfall and severe cooling weather to the launch site, and issued a meteorological warning to the headquarters. The launch site weather forecast says:

In the next three days, the launch site will continue to snow, and then there will be a big cooling. The lowest temperature is expected to reach MINUS 26 to 27 degrees. The wind speed at high altitude can reach up to 42 meters per second!