October 2021 - Page 3 of 5 - Climate Impact Company

News

10/20/2021, 9:03 am EDT

Now Adding East/Southeast Days 6-10 To Heavy Rain Zones

New to the forecast is a developing heavy rainfall regime developing in the East/Southeast centered on the 6-10-day period according to ECM. Most of the rainfall is mid-to-late period as a Pacific trough arrives and regains strength while entraining Gulf of Mexico moisture. Heavy rain causing flash flooding is possible from the Tennessee Valley to the Mid-Atlantic States and Southeast also featuring severe thunderstorms during October 27-29.

10/18/2021, 5:22 am EDT

The Northeast Pacific Horse Shoe SSTA Pattern Emerging – Should ENHANCE La Nina Climate Into Early 2022

For the first times since 2012, the cool “horse shoe” SSTA pattern stretching from the Gulf of Alaska to just-off the West Coast of North America and southwestward to the south of Hawaii toward the Dateline in the Pacific tropics has emerged. Presence of the cool “horse shoe” SSTA pattern coupled with La Nina normally increases the risk and amplitude of La Nina climate signals which includes heavy precipitation during NOV/DEC/JAN in the Northwest U.S., dryness leading to drought in the Mid-south States and a general warmer-than-normal national pattern.

10/15/2021, 1:45 pm EDT

Northeast Pacific Horseshoe SSTA Pattern Forming

The Gulf of Alaska has cooled off considerably this autumn season and is cooler than normal for the first time since 2012. More recently, the cool waters have evolved off the U.S. West Coast. The California Ocean Current is up-welling subsurface cool waters causing a horseshoe cool anomaly to form from the Gulf of Alaska to the California Coast and southwestward toward Hawaii.

10/15/2021, 4:50 am EDT

La Nina Arrives; Looks Like La Nina Modoki

NOAA/CPC announced yesterday (Oct. 14) that La Nina onset developed in October 2021. The surface/subsurface cool anomalies in the equatorial East Pacific suggest La Nina Modoki. The projected ENSO West-East index (WEI) for October suggests La Nina Modoki. The La Nina episode is forecast to last into early northern hemisphere spring 2022.