000
WTPZ43 KNHC 090235
TCDEP3
 
Tropical Storm Cosme Discussion Number   3
NWS National Hurricane Center Miami FL       EP032025
800 PM MST Sun Jun 08 2025

Cosme is gradually improving in organization with deep convection 
pulsing, albeit with the center on the northern edge of the 
convection.  A recent microwave pass did show a prominent curved 
band especially in the southern semicircle of the storm.  The 
initial wind speed will stay at 40 kt for this advisory, between 
the lower subjective Dvorak estimates and higher objective values.  

Conditions look conducive for strengthening for about the next 24 
hours while Cosme moves within a fairly low shear and warm SST 
environment.  Thereafter, some increase in easterly shear is 
possible, and the storm should move over a tight SST gradient into a 
drier airmass.  Cosme is forecast to respond to these conditions by 
weakening quickly by midweek.  The only change to the previous 
forecast is a small reduction in the intensity forecast at 60 and 72 
h, consistent with the latest model consensus.  It would not be 
surprising to see Cosme become a remnant low faster than shown 
below.

The storm continues moving northwestward at 8 kt, and a 
west-northwest to northwest motion is anticipated during the next 
day or so.  After that time, Tropical Storm Barbara causes a
mid-level ridge to erode, and Cosme should respond by taking a 
sharp turn to the northeast around Barbara.  Model guidance has 
shifted notably to the left this evening, suggesting a 
little more separation of the tropical cyclones before they 
interact.  While the new forecast is adjusted to the west, this is 
not a particularly confident longer-range forecast due to 
the complexity of the interaction.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/0300Z 13.7N 111.9W   40 KT  45 MPH
 12H  09/1200Z 14.4N 112.9W   50 KT  60 MPH
 24H  10/0000Z 14.9N 114.1W   60 KT  70 MPH
 36H  10/1200Z 15.3N 114.2W   60 KT  70 MPH
 48H  11/0000Z 15.8N 113.8W   55 KT  65 MPH
 60H  11/1200Z 16.9N 113.0W   40 KT  45 MPH
 72H  12/0000Z 18.5N 113.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  13/0000Z...DISSIPATED
 
$$
Forecaster Blake