|Tropical Storm Cosme||Winds: 45 kt|
|Pressure: 999 mbar|
|Advisory 3 / 8:00 PM PDT Saturday July 6, 2019|
Cosme is barely worthy of its designation as a tropical cyclone this evening. Satellite imagery highlights a fairly well-defined circulation, especially compared to the absolute mess its associated convection is in. The concentrated area of thunderstorm activity that had formed earlier today has fizzled out in recent hours, mainly due to changes in the upper-level environment. Wind shear was clearly on the decline this morning and early afternoon, with outflow expanding to the north and west. However, shortly after the previous advisory, outflow began to retreat back toward the center of circulation, an indication that wind shear has at least temporarily increased again. Due to the poor shape of the convection, satellite intensity estimates remain a very paltry T1.5/25kt from SAB and T2.5/35kt from TAFB. In the absence of satellite wind data, Cosme would be classified as a tropical depression. However, the initial intensity is instead set to 45kt based on the earlier ASCAT pass.
The environment Cosme finds itself in is not conducive, and it will only become less so with time. In addition to the wind shear that SHIPS is having a hard time computing, ocean temperatures are expected to fall below 27C tonight and below 26C about a day from now. Water vapor imagery shows an abundance of dry air near and west of the tropical cyclone, and this will continue to be injected into the circulation. Thus, no further intensification is expected, and Cosme is expected to degenerate to a remnant low about 2 days from now. This could plausibly occur sooner. Dissipation is expected on day 4.
Due to the broad circulation of Cosme, with multiple vortices embedded within the larger center, the motion is difficult to track. At best guess, the storm appears to be moving steadily west-northwest. A west-northwest to northwest trajectory should continue for the next 48 hours. Thereafter, once Cosme degenerates, it will be steered by the typical low-level easterly trade wind flow across the East Pacific.
FORECAST MAX WINDS
INIT 07/0300Z 45 KT 50 MPH
12H 07/1200Z 45 KT 50 MPH
24H 08/0000Z 40 KT 45 MPH
36H 08/1200Z 35 KT 40 MPH
48H 09/0000Z 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 10/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW96H 11/0000Z...DISSIPATED