Tropical Storm Norbert

000
WTPZ44 KNHC 140841
TCDEP4
 
Tropical Storm Norbert Discussion Number  19
NWS National Hurricane Center Miami FL       EP142026
1100 PM HST Sun Sep 13 2026

A renewed burst of deep convection, with cloud-top temperatures as 
cold as -80 C, has developed over and east of Norbert's circulation 
center due to increasing westerly vertical wind shear. Despite the 
recent increase in convection, an ASCAT-C scatterometer pass showed 
an asymmetric wind field with peak winds of 34 kt north of the 
center. Based on these data, the initial intensity is lowered to 35 
kt.

The initial motion is estimated to be westward, or 280/11 kt. The 
storm remains positioned south of a subtropical ridge, which should 
steer Norbert on a general west-northwestward to westward track for 
the remainder of the forecast period. The track guidance remains in 
fairly good agreement, and the NHC track forecast is largely 
unchanged, reflecting a blend of the previous forecast with the 
latest HFIP corrected consensus approach (HCCA) and Google DeepMind 
ensemble mean (GDMI).

A combination of mid-level dry air and strengthening westerly 
vertical wind shear should make it increasingly difficult for 
Norbert to maintain organized deep convection, resulting in a steady 
weakening trend over the next couple of days. The current NHC 
intensity forecast is largely an update of the previous advisory and 
shows Norbert degenerating into a remnant low by Tuesday and 
dissipating as it opens into a trough by Wednesday.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/0900Z 19.3N 136.4W   35 KT  40 MPH
 12H  14/1800Z 19.7N 138.4W   35 KT  40 MPH
 24H  15/0600Z 20.2N 141.2W   30 KT  35 MPH
 36H  15/1800Z 20.5N 143.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  16/0600Z 20.7N 146.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  16/1800Z...DISSIPATED
 
$$
Forecaster Pierce/Gibbs