Invest 96E nearly a tropical depression, no threat to Mexico; Atlantic basin quiet
A large area of disturbed weather in the East Pacific a few hundred miles south of the Mexican coastline, Invest 96E, has continued to become better defined, and is very close to attaining tropical depression status, if it has not already done so. As of the 0Z ATCF update, maximum sustained winds were estimated at 35 mph with a minimum barometric pressure of 1005 millibars. The system was located at 11.5N 104.7W, and moving off towards the west-northwest at 10 mph. Infrared satellite loops reveal that 96E is a large system, but has built up a well-defined center of circulation underneath a recent large burst of deep convection. The latest Tropical Weather Outlook gave the disturbance a high chance, 90%, of becoming a tropical cyclone during the next 48 hours, stating that a tropical depression could form at any time. Based on Dvorak intensity estimates of T2.0/T2.0 from the NESDIS Satellite Analysis Branch, I believe that 96E has attained tropical depression status at this time.
Figure 1. Infrared satellite imagery of Invest 96E.
The forecast for 96E
The track forecast for Invest 96E is pretty much straightforward, as evidenced by the spectacular model consensus for this disturbance. A large and powerful ridge of high pressure encompasses much of the United States, not only bringing record heat to many locations across the country, but preventing any disturbance in the East Pacific to recurve towards the Mexican coastline. All global models show that this ridge should remain intact over the coming days, and possibly even build farther west, and subsequently, a west-northwest to westward movement is expected over the next 120 hours. In the long range, it is possible that moisture from 96E could reach the island of Hawaii, but not much of the system is likely to be left by then.
The intensity forecast for 96E is a little more complicated, simply because of the fact that many of the global models foresee little to no intensification of the disturbance despite the seemingly favorable conditions. Current wind shear as analyzed by the SHIPS model remains in the low category, near 10 knots, and is forecast to lower slightly over the coming days. Water Vapor satellite imagery reveals that the system is embedded within a moisture environment, and Sea Surface Temperatures lie near 29 °C. That being said, a majority of the intensity guidance models show 96E attaining tropical storm status within 24 hours, with peak intensity between 72-96 hours out as a strong tropical storm. Weakening is shown thereafter as the system enters a drier environment. The forecast for this blog lies a little higher than the model consensus due to the unpredictability of East Pacific storms and the idea that the system may strengthen a little more than forecast over the next three days.
...FORECAST POSITIONS AND MAX WINDS...
INIT 04/0300Z 11.5N 104.7W 30 KT 35 MPH
12H 04/1200Z 12.8N 106.3W 30 KT 35 MPH
24H 05/0000Z 13.8N 108.0W 35 KT 40 MPH
36H 05/1200Z 14.2N 110.0W 40 KT 50 MPH
48H 06/0000Z 14.4N 111.9W 55 KT 65 MPH
72H 07/0000Z 14.4N 115.5W 70 KT 80 MPH
96H 08/0000Z 14.8N 119.0W 65 KT 75 MPH
120H 09/0000Z 15.5N 122.8W 60 KT 70 MPH
Elsewhere in the tropics
All global models, including the highly reliable ECMWF and GFS, foresee a second tropical cyclone developing in the East Pacific this week, and many of them make the disturbance a respectable hurricane. It is likely that anything that develops will head away from the Mexican coastline and pose no threat to land as a tropical cyclone.
The Atlantic is quiet, with no areas of interest at the current time. Development chances are likely to stay low over the next two weeks, and our next good chance for tropical development will not occur until after July 17 as the MJO returns to Octants 8 and 1. Enjoy the peace while it lasts.