The first “Invest” of the year for the Eastern Pacific – 90E – was designated Monday afternoon. 90E has a medium chance of tropical cyclone development within the next five days, but conditions are expected to become less conducive for development by late week and into the weekend. 90E is no threat to any land areas.

An Invest – short for area of investigation – is an area of disturbed weather being monitored for possible tropical or subtropical development. Invests are numbered from 90 to 99 with a letter at the end for the basin that the invest is located in (in the case of the EPAC, the letter is E). After Invest 99E, the next invest would be numbered 90E, and the numbering will start over.

As of 18:00 UTC Monday, Invest 90E was located near 9.0°N 119.0°W and was moving generally west-northwestward. Maximum sustained winds were 20 knots (25 mph), with an estimated minimum pressure of 1009 mb. The National Hurricane Center (NHC) gives 90E a 30 percent chance of development within 48 hours, and a 40 percent chance within five days. During the next 48 hours, conditions are quite favorable for development. Sea surface temperatures are near 28°C (84.2°F), with low wind shear (less than 10 knots) and a moist environment (mid-level relative humidity values near 75 percent). However, conditions are expected to gradually become worse for development by Thursday, as wind shear increases to around 20 knots and sea surface temperatures drop to around 26°C (78.8°F).

The 12z GFS, ECMWF, CMC, and UKMET model runs all predicted at least a tropical depression would develop from 90E. However, none of the models predicted a hurricane. I think the environment is conducive enough for a weak to moderate tropical storm to form. It should be noted, however, that this would be quite unusually far west for an Eastern Pacific tropical cyclone to develop this time of year. 90E has a chance to tie or break the record for the earliest tropical cyclone in the Eastern Pacific proper, set just last year with Tropical Storm Adrian at 18:00 UTC on May 9.

I will be back with an update on 90E on Tuesday. If 90E becomes a tropical storm, it would be named Aletta. The Atlantic basin looks quiet in the near future, but this is not surprising considering the Atlantic hurricane season does not officially begin for 25 more days.