We have a new record in the tropics. It’s late April but Eastern Pacific already got its first system today – Tropical Depression One-E is the earliest eastern Pacific cyclone on record. It is packing winds of 30 knots, central pressure around 1006 mbar. Although it stays away from any land areas, it is remarkable early start.

One-E began as a tropical disturbance/wave that gradually organized in the open Eastern Pacific, a region where strong wind shear and cool waters normally inhibit tropical development so early in the year. But this time, a low wind shear allowed a healthy upper-level outflow providing good ventilation to the system. The depression also formed over the unusually warm water, with sea surface temperatures of 27-28°C, roughly 1 °C above the long-term average.

Here are the latest satellite images in visible and infrared channels. A compact area of deep convection is nicely visible to the south of the main circulation, with still quite a good outflow ventilation:

Infrared satellite image of tropical depression One
visible satellite depression one-e


https://twitter.com/EricBlake12/status/1254037272200187905

The overall organization of the depression reveals a quite well-defined but exposed center is displaced to the north of the convection area. The wave will continue moving west-northwest over the next few days and should not intensify any further. The system will gradually dissipate over the next few days while coming into dry mid-level air, increasing shear and cooler sea surface temperatures.

tropical depression One track

Here is an amazing graphics for the books – the first formations by year for tropical cyclones in the eastern North Pacific since 1949. Tropical Depression One-E is the earliest eastern Pacific tropical cyclone on record – two weeks ahead of schedule:


2020 Pacific hurricane season – Tropical Depression One-E

See also:

Category 5 hurricane Dorianat central pressure of 909-911 mbar with sustained winds of 185 mph, Abaco islands (Bahamas)

Tropical Cyclone #HAROLD becomes the 2nd strongest cyclone to hit Vanuatu on record