243 
WTPZ44 KNHC 142041
TCDEP4
 
Tropical Storm Norbert Discussion Number  21
NWS National Hurricane Center Miami FL       EP142026
Issued by the NWS Weather Prediction Center College Park MD
1100 AM HST Mon Sep 14 2026
 
Deep convection is decreasing in intensity and coverage east 
of Norbert's center with warming cloud-top temperatures. The center 
is becoming exposed to the southwest of the convection, while also 
becoming more elongated in nature. These factors suggest that a 
weakening trend is imminent. However, satellite intensity estimates 
have not changed in the past several hours, and a scatterometer pass 
around 1830z still depicted max winds of 35 kt northeast of the 
center. Thus the initial intensity is maintained at 35 kt.
 
The initial motion is estimated to be westward, or 280/13 kt. The
storm remains positioned south of a subtropical ridge, which should
continue to steer Norbert on a general west-northwestward to
westward track until it dissipates in a couple days. The track
guidance remains in good agreement, and the NHC track forecast is
just slightly south of the previous one.
 
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 system is
expected to become post-tropical on Tuesday, and then open into a
trough by Wednesday. The new forecast shows an earlier transition 
to a post-tropical cyclone and subsequent dissipation.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/2100Z 19.7N 139.2W   35 KT  40 MPH
 12H  15/0600Z 20.0N 141.3W   30 KT  35 MPH
 24H  15/1800Z 20.2N 143.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  16/0600Z 20.4N 146.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  16/1800Z...DISSIPATED
 
$$
Forecaster Chenard/Blake