Tropical Storm Norbert

000
WTPZ44 KNHC 121434
TCDEP4
 
Tropical Storm Norbert Discussion Number  12
NWS National Hurricane Center Miami FL       EP142026
500 AM HST Sat Sep 12 2026
 
This morning's conventional satellite presentation consists of an
amorphous blob of deep convection near the surface center that has
been bursting intermittently during the past several hours.  A 1132
UTC AMSR3 color composite microwave image indicated that the
surface center remains near the southern edge of the convective
mass.  The objective and subjective intensity estimates are
unchanged from 6 hours ago, and the initial intensity is set at 50
kt.

Norbert's initial motion is estimated to be west-northwestward, or 
285/9 kt, and this general motion should continue through the 
weekend.  Afterward, a subtropical ridge to the north of the 
cyclone should steer Norbert in a westward heading through most 
of next week.  There has been a shift toward the north of the 
majority of the skilled models from the previous advisory, which 
has in turn placed the forecast track in increasingly unfavorable 
environmental conditions.  Consequently, the official track 
forecast has been shifted to the right of the previous one and lies 
close to the GDMI ensemble mean and HCCA consensus aid.
 
Although Norbert has been moving over warm oceanic surface
temperatures, marginal moisture content in the low- to mid-levels
and southerly vertical shear have been suppressing the tropical 
cyclone's opportunity to strengthen significantly.  In fact, only 
the HFIP HCCA and the Google DeepMind WeatherNext 2 (GDMI) show 
some strengthening during the short term.  Through the remaining 
forecast period, because of the significant northward adjustment of 
the models, gradual weakening is expected beginning early next week, 
and Norbert should become a post-tropical remnant low early Thursday 
(day 4).  The NHC intensity forecast follows suit and has been 
adjusted downward from the previous forecast beyond the 24 hours. 
 
Norbert's 34-kt wind radii have been expanded in the north
semicircle based on a 0842 UTC OSCAT-3 scatterometer overpass.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  12/1500Z 17.3N 128.3W   50 KT  60 MPH
 12H  13/0000Z 17.7N 129.7W   55 KT  65 MPH
 24H  13/1200Z 18.1N 131.6W   55 KT  65 MPH
 36H  14/0000Z 18.4N 133.7W   50 KT  60 MPH
 48H  14/1200Z 18.6N 136.0W   45 KT  50 MPH
 60H  15/0000Z 18.7N 138.5W   40 KT  45 MPH
 72H  15/1200Z 18.6N 141.1W   35 KT  40 MPH
 96H  16/1200Z 17.7N 146.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  17/1200Z 15.9N 151.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Roberts