Fall Hurricane Outlook for Late September 2020 by Dr. Ryan Truchelut – issued 23 September 2020 Key Points WeatherTiger’s outlook for the fall months…
Articles by Ryan Truchelut
WeatherTiger’s first look at winter 2020-2021 is for a cool and typically snowy winter in the Northern Plains and Great Lakes, and warmer and drier conditions in the U.S. southern tier and Eastern Seaboard.
The Pacific has cooled slightly since April, with more rapid cooling beneath the surface indicative of trends into summer. Overall, global circulation patterns continue to reflect ENSO neutral conditions, albeit with a stronger than normal subtropical jet in the eastern Pacific. WeatherTiger’s ENSO Whisperer output for May is a bit more hedged than last month’s on the potential for late summer or fall La Niña development. Our model suggests that observed cooling will persist into mid-summer, followed by an extended period of cool-neutral anomalies.
Spring 2020 begins with much of the central U.S. growing region experiencing saturated soils due to excessive precipitation over the last 12 months. These extreme initial conditions raise the specter of another year of delayed or prevented planting across much of the central and eastern U.S., as characterized spring 2019. Widespread planting delays occur when extreme spring precipitation meets existing soil saturation. In our view, the Delta and Deep South are most at risk for delayed planting, with some possibility of localized delays in the eastern and southern Ohio Valley. These regions are most likely to see continued above normal rainfall through May.
The Pacific has changed little in March and early April, warm-neutral anomalies remaining in place. Overall, global circulation patterns continue to reflect ENSO neutral conditions, with a slight lingering tilt towards Nino-ish influences as reflected by a strong subtropical jet.
WeatherTiger’s first look at the 2020 hurricane season is for a 50% chance of an above average year, with a 30% chance of near-normal and 20% chance of below-normal cumulative activity. The median of our forecast is about 145% of average hurricane season activity, or around 16 named storms, eight hurricanes and four major hurricanes.
The Pacific warmed slightly in November overall, but atmospheric and oceanic conditions still reflect a warm-neutral ENSO state. WeatherTiger’s ENSO Whisperer output expects that ENSO will stay in neutral conditions into early 2020, with El Nino odds increasing a bit into the spring months.
The 2010s were a decade of contrasts for Atlantic hurricanes. Despite darkest timeline storms like Sandy, Irma, and Michael, it was an era of remarkable luck for the continental U.S. coast. We’re taking stock of the 2010s and applying the lessons learned to understand what the U.S. can expect from the hurricane seasons of the 2020s and beyond.
Our model is unchanged in expecting continued ENSO-neutral conditions into early spring 2020.