Monday, September 1, 2014

September 14-18 Potential Storm System

A storm system may impact the US between September 14-18.

Tropical Tidbits
The image above shows 500mb geopotential height anomalies over the Western Pacific. Oranges and reds indicate the presence of ridging, typically resulting in warm, quiet weather. Blues tell the presence of below normal height anomalies, normally seen by stormy and cold weather. On the forecast image above, valid on September 8th, slightly below normal height anomalies are observed just to the east of Japan.

As has been discussed consistently for the past couple of years, the weather in East Asia can have a significant impact on weather here in the United States. Utilizing the East Asian correlation of ridging over Japan equals ridging in the US 6-10 days later, and the same situation with negative height anomalies, we can foresee long range weather patterns weeks out at a time. This mechanism is referred to as the Typhoon Rule, and states that weather patterns found at the 500mb level can replicate themselves over North America 6-10 days later after they appear over Japan.

By using this rule, and observing the presence of a storm system just east of Japan on September 8th, we can reasonable determine that a storm system may affect the United States around a September 14-18 timeframe. The areas affected will be determined at a later date, as the mere existence of this storm is still in question.