Tropical Cyclone Discussion

551
WTPZ44 KNHC 122057
TCDEP4
 
Tropical Storm Norbert Discussion Number  13
NWS National Hurricane Center Miami FL       EP142026
1100 AM HST Sat Sep 12 2026
 
A 1712 UTC ASCAT-B pass revealed that Norbert's center is located 
near the southern edge of a compact mass of deep convection, and the 
wind field is asymmetric, favoring the northern side. The 
scatterometer data showed peak wind vectors of 42 kt within the 
northwestern quadrant, and based on that data, the current 
intensity is lowered to 45 k.

Norbert continues to move west-northwestward, or 285/10 kt, located 
to the south of the subtropical ridge extending westward from 
northern Mexico. The ridge is expected to keep Norbert on a 
west-northwestward to westward heading for the remainder of the 
forecast period. However, there has been another northward shift in 
the track model guidance, and the NHC official forecast has been 
moved in that direction using a blend of the previous forecast with 
the latest HCCA and GDMI aids, which lie along the northern 
boundary of the guidance envelope.

The additional northward shift in Norbert's expected track will 
take it further into the zone of strong westerly shear that extends 
across much of the central Pacific basin, including over Hawaii. 
Little change in strength is expected during the next 24 hours 
while the shear still remains relatively low, but increasing shear 
and a marginal thermodynamic environment should cause additional 
weakening to begin on Sunday. In fact, the nearly all of the models 
respond to the hostile environment by showing Norbert dissipating 
into a trough of low pressure several hundred miles east-southeast 
of Hawaii potentially as early as Wednesday. For this update, the 
NHC forecast shows Norbert degenerating into a remnant low by 
Wednesday and dissipating by Thursday before reaching the longitude 
of the Hawaiian Islands.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/2100Z 17.6N 129.6W   45 KT  50 MPH
 12H  13/0600Z 18.0N 131.1W   45 KT  50 MPH
 24H  13/1800Z 18.5N 133.2W   45 KT  50 MPH
 36H  14/0600Z 18.8N 135.4W   40 KT  45 MPH
 48H  14/1800Z 19.1N 138.0W   35 KT  40 MPH
 60H  15/0600Z 19.3N 140.7W   35 KT  40 MPH
 72H  15/1800Z 19.3N 143.4W   30 KT  35 MPH
 96H  16/1800Z 18.5N 149.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  17/1800Z...DISSIPATED