Subtropical Storm Josephine Discussion Number   1
NWS National Hurricane Center Miami FL       AL102026
500 PM AST Wed Oct 21 2026

The non-tropical area of low pressure (Invest AL93) that we have 
been monitoring this week has acquired enough subtropical 
characteristics to be considered a subtropical storm.  
Scatterometer data showed that fronts near the cyclone had 
dissipated, with a smaller radius-of-maximum wind than yesterday.  
Additionally moderate-to-deep convection has been organizing near 
and west of the warm-core center.  Thus, advisories have been 
initiated on a subtropical storm, and 55 kt is shown as the initial 
intensity based on the scatterometer data.

Josephine has been moving slowly northward today as a shortwave 
ridge passes across the northeastern United States.  The storm 
should accelerate northeastward tomorrow as a mid-latitude trough 
digs into the Great Lakes and Northeastern United States, taking 
the system away from the US.  By Friday, the low should turn 
eastward, to the south of Newfoundland.  Model guidance is in good 
agreement on this path, and the new forecast is close to a blend of 
the global model consensus and the NOAA corrected-consensus aid 
HCCA.

The subtropical storm will likely intensify during the next day or 
so through a favorable trough interaction while it remains near the 
north wall of the Gulf Stream.  Global models are in good agreement 
on a band of hurricane-force winds developing tomorrow on the back 
side of the low as it undergoes extratropical transition.  A slow 
weakening is anticipated by late Friday with the loss of forcing 
from the trough while the system moves over cold water.  The NHC 
intensity forecast is similar to a blend of the GFS/ECMWF global 
model solutions.  The cyclone should become absorbed in about 4 
days within a much larger low over the North Atlantic.  

Since the coastal wind hazards with this system have been covered 
for the last several days through non-tropical products issued by 
local National Weather Service offices, and the system is forecast 
to move away from the coast, those products will remain in effect 
until the threat diminishes.


FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 37.4N  69.5W   55 KT  65 MPH...SUBTROPICAL
12H  22/0600Z 38.1N  69.0W   60 KT  70 MPH...SUBTROPICAL
24H  22/1800Z 39.6N  66.2W   65 KT  75 MPH...POST-TROP/EXTRATROP
36H  23/0600Z 41.4N  61.6W   70 KT  80 MPH...POST-TROP/EXTRATROP
48H  23/1800Z 43.3N  56.9W   60 KT  70 MPH...POST-TROP/EXTRATROP
60H  24/0600Z 44.1N  53.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
72H  24/1800Z 44.4N  50.4W   45 KT  50 MPH...POST-TROP/EXTRATROP
96H  25/1800Z 43.5N  37.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  26/1800Z...DISSIPATED

$$
Forecaster Blake