May 2020 - Climate Impact Company

05/31/2020, 2:19 pm EDT

Explaining Recent Tendency for Stalled U.S. Coastal Tropical Cyclones

Important to seasonal prediction of North Atlantic tropical cyclone activity is the evolution in recent years of the North Atlantic Warm Hole and the attendant upper air pattern. During the tropical cyclone season a persistent upper level trough has formed in the cooler atmosphere across the NAWH compensated for by a persistent upper ridge over Quebec (and vicinity). When the upper ridge is present as tropical cyclones go inland the U.S. coastline storms slow down and produce excessive rainfall similar to Harvey (2017), Florence (2018) and Imelda (2019). A similar dynamic is expected for AUG/SEP 2020.

05/29/2020, 8:31 am EDT

Why La Nina Could Be Stronger

Global SSTA models are forecasting a major contrast between ocean surface temperatures across the eastern equatorial Pacific (cool) versus the far western Pacific and eastern Indian Oceans (warmer). The contrasting ocean temperatures lead to stronger trade winds across the eastern Pacific tropics possibly increasing La Nina strength and duration.

05/25/2020, 10:15 am EDT

Indian Ocean Dipole (-IOD) AND La Nina Increases Risk of Stronger La Nina Climate AND La Nina Lingering Into Next Year

Evolution of La Nina during negative phase of the Indian Ocean Dipole suggest that the attendant convection patterns associated with this regime will be stronger and have a more dramatic impact on global La Nina climate. Both strength of La Nina climate anomalies could be stronger and La Nina could linger in 2021.

05/21/2020, 12:00 pm EDT

NOAA 2020 North Atlantic Hurricane Outlook

NOAA/NHC issues their 2020 North Atlantic basin tropical cyclone activity forecast. The outlook indicates above normal activity similar to forecasts issued in early April by other leading (market) providers. The seasonal forecast indicates 13-19 tropical storms, 6-10 hurricanes and 3-6 major hurricanes.

05/19/2020, 10:44 am EDT

Warmer Than Normal Ocean Surface Lead To Frequent and More Powerful Tropical Cyclones This Season

Already three tropical cyclones have formed in the northern hemisphere before the official June 1 start to the tropical cyclone season. Warmer-than-normal ocean water played a key role in leading to the formation of Arthur east of Florida, rapid intensification of Vongfong to a category 3 tropical cyclone before striking the Philippines and emergence of a category 5 tropical cyclone (Amphan) in the Bay of Bengal.

05/15/2020, 8:58 am EDT

Kansas Dryness Expanding and Intensifying

The lack of rainfall across the west/southwest Great Plains continues. The result is the development of D3/D2 drought in southwest Kansas which is expanding. The dryness in this zone features BOTH shallow and deep layer moisture deficits making this region susceptible to intense flash drought if hot weather over a period of 7-10 days develops during the summer season.

05/13/2020, 10:43 am EDT

Possible Early Season Tropical Cyclone Next Week

An area of shower activity across Cuba is forecast to slowly expand and gain intensity the next few days. By the weekend a low pressure area forms in the western Bahamas and drifts slowly northward. There is a 35% chance that the system is sufficiently organized to transition into a minimal tropical storm (Arthur) early next week while continuing a northeastward drift eventually accelerating out to sea.

05/11/2020, 12:24 pm EDT

Subsurface East Pacific Cools Dramatically: La Nina Is On the Way!

A leading indicator of ENSO phase change is a sudden change in the equatorial East Pacific subsurface temperature anomaly analysis. The latest analysis by NOAA/CPC indicates a DRAMATIC late April/early May cooling east of the Dateline. The risk of La Nina developing in AUG/SEP/OCT 2020 as indicated by several forecast models is well-supported by this cooler subsurface Pacific diagnostic.

05/10/2020, 9:48 am EDT

Weak La Nina Likely During Tropical Cyclone Season

The steady loss of heat in the subsurface equatorial Pacific Ocean east of the Dateline is an indicator that some forecast models that indicate La Nina for later this summer are on target! A weak La Nina substantially increases hurricane risk in the North Atlantic,

05/06/2020, 10:38 am EDT

Global Soil Moisture Regime At The End of April 2020: Very wet!

Despite the large amount of wet soil regions there are some important drought areas. The strongest dry area emerging is across southwest Brazil’s second corn crop and extending across the Parana River basin. This zone trended much drier the past 2-3 months. A second key drought area is across the south and southwest Russia wheat belt extending to Romania also trending drier through early 2020 (but receiving rainfall in early May).

05/03/2020, 12:37 pm EDT

The U.S. Population Weight HDD Anomalies for the 2019-20 Cold Season

The 2019-20 U.S. cold season monthly population weight HDD ranks indicate a chilly start (November 4th coldest) and end (April ranked 3rd coldest) of the season with exceptionally warm climate through the core of the winter season lead by the 2nd warmest January in the 20-year climatology.