Tremendous Snowfall During Last Occurrence… Caution For What’s Ahead
During September, the Japan Meteorological Agency announced that La Nina, a phenomenon that brings about abnormal weather throughout the world, is expected to occur this year. The last occurrence of La Nina was during the autumn of 2017 until the spring of 2018, which was a factor connected to the record levels of heavy snow during February 2018 within Fukui Prefecture. Regarding the amount of snowfall for this winter, the Fukui Local Meteorological Office expressed, “It is almost certain that it will not be a warm winter. However, it is not accurate to say ‘La Nina = heavy snow’. There is no need for great concern, but we must be cautious.”
La Nina is a weather phenomenon where the sea surface temperature decreases across the equatorial Eastern Central Pacific Ocean, and increases around Indonesia and the Philippines. With a high chance of persisting through the winter, the Hokuriku region will likely see heavy rain or snow during the early winter season.
Such weather will lead to the prevailing westerlies over the vicinity of Japan to meander further south than in a regular year. The Siberian High will grow slightly stronger, stretching towards the southeast, making it easier for the cold air to flow into the west part of Japan, including into Fukui Prefecture.
However, on September 25th, the Niigata Local Meteorological Office reported that the winter season (December to February) within Hokuriku is predicted to see “roughly normal levels” of rain and snow. Heavy snowfall would depend on the formation of the “Japan sea Polar air mass Convergence Zone” (JPCZ). The cold stream flowing from the Siberian region will split in two as it hits the mountain ranges within the Korean peninsula. The streams will then reconverge over the Japan Sea, into the JPCZ, creating snow-laden clouds, one after another, leading to the plains along the shore receiving an increased level of snowfall, as is characteristic with this phenomenon.
A weather forecaster with the Fukui Local Meteorological Office, Komyo Nagai, expressed, “There are many factors which are difficult to predict, including how the cold air will travel in and if the JPCZ will spread over areas of Fukui Prefecture.” He continued, “Actually heading towards the winter season, we should pay attention to the forecasts and prepare accordingly.”