Invest 91E has substantially improved in organization since this morning. The system has had persistent deep convection this afternoon, but the convective activity is currently not quite well organized enough for the system to be designated a tropical depression. As of their 5:00 PM PDT Tuesday Tropical Weather Outlook, the National Hurricane Center raised the two-day development chances to 70 percent and the five-day probability to 80 percent.

91E is currently a sprawling area of low pressure with a large convective canopy. At 18:00 UTC this afternoon, 91E was centered near 13.5°N 98.2°W.However, the convection has not yet consolidated around the center of the low. Convection has recently decreased, but this is normal, as it is related to the approach of the diurnal convective minimum. The convection will need to consolidate around the center more for the National Hurricane Center to designated 91E as Tropical Depression Two-E.

An ASCAT pass captured the eastern half of 91E earlier (around 16:25 UTC) and showed that its circulation was gradually becoming better defined, with west winds developing around the southern side of the system. 91E is likely in the process of closing off a circulation, which is one of the key components of a tropical cyclone. The ASCAT pass also showed winds of at least 25 knots (30 mph). Based on recent trends…I have increased my chances of 91E’s development to 70 percent in both 48 hours and 5 days. This is despite the fact that the 12z ECMWF run only shows minimal development of the system. In contrast, the 18z GFS run shows a tropical depression. The 18z SHIPS model for 91E showed mostly favorable conditions ahead for the next few days, with shear remaining below 15 knots, along with sea surface temperatures around 29.5°C, substantially warm enough to support a tropical cyclone. Despite the favorable conditions, the system’s large size and proximity to land is likely to prevent any significant intensification, and I expect a moderate tropical storm at the absolute most. If development occurs, 91E/02E will likely struggle to reach tropical storm status, and may not even become named. If it does acquire winds of 39 miles per hour or greater, it will be named Tropical Storm Beatriz. 91E only has a short life ahead, with most models showing the system degrading to a remnant low prior to landfall. This is a somewhat common location for late May and early June East Pacific systems.

I will be back tomorrow for another update on Invest 91E, or Tropical Depression Two-E if it is designated as a tropical depression by the time of my next post.