Tropical Storm Cosme Forecast Discussion Number 8

Jun 10, 2025 - 08:00
Tropical Storm Cosme Forecast Discussion Number 8
Issued at 200 AM MST Tue Jun 10 2025
812 
WTPZ43 KNHC 100850
TCDEP3
 
Tropical Storm Cosme Discussion Number   8
NWS National Hurricane Center Miami FL       EP032025
200 AM MST Tue Jun 10 2025

The convective appearance of Cosme has changed little since the 
previous advisory.  The latest subjective Dvorak estimates from 
TAFB and SAB range from 55-65 kt, and the latest objective 
intensity estimates from UW-CIMSS range from 54-59 kt.  The initial 
intensity is held at 60 kt for this advisory, based on a blend of 
the intensity estimates.

Cosme continues to move very slowly toward the northwest, with 
motion estimated at 300/4 kt. A slow motion, perhaps more toward 
the north, should continue for at least the next 12 h since the 
overall steering currents are weak, due to Barbara's current 
position in relation to Cosme.  However, as Barbara weakens, Cosme 
will accelerate north-northeastward in response to ridging located 
to the northwest of the cyclone. Very little change has been made 
to the NHC track forecast, and the latest forecast is near the 
various consensus models.

Cosme is forecast to remain in favorable enough conditions for the 
next 24 h such that the cyclone might be able to maintain its 
intensity or only weaken very slowly.  However, after that time, as 
Cosme gains latitude, it will encounter cooler water and drier air. 
Cosme is forecast to lose its convection and become post-tropical on 
Wednesday, in agreement with the GFS and ECMWF simulated satellite 
imagery products.  The post-tropical low is then forecast to 
gradually weaken and dissipate by 72 h.  The NHC intensity forecast 
is similar to the previous one, and is near the middle of the 
guidance envelope.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  10/0900Z 15.3N 114.5W   60 KT  70 MPH
 12H  10/1800Z 15.5N 114.6W   55 KT  65 MPH
 24H  11/0600Z 16.2N 114.1W   50 KT  60 MPH
 36H  11/1800Z 17.4N 113.4W   35 KT  40 MPH...POST-TROPICAL
 48H  12/0600Z 18.7N 113.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  12/1800Z 19.8N 113.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  13/0600Z...DISSIPATED
 
$$
Forecaster Hagen/Gibbs