Tropical Cyclone Discussion

998
WTPZ44 KNHC 141437
TCDEP4
 
Tropical Storm Norbert Discussion Number  20
NWS National Hurricane Center Miami FL       EP142026
Issued by the NWS Weather Prediction Center College Park MD
500 AM HST Mon Sep 14 2026
 
Deep convection, with cloud-top temperatures as cold as -80 C, has 
continued near and east of Norbert's center.  The center is on the 
southwestern edge of the convective mass due to shear.  Satellite 
intensity estimates have not changed in the past few hours, so 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 few days. The track 
guidance remains in good agreement, and the NHC track forecast is 
basically an update 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 with the system 
expected to become post-tropical on Tuesday. The current NHC
intensity forecast is a little less than the previous one and shows 
Norbert dissipating as it opens into a trough by Wednesday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/1500Z 19.4N 137.8W   35 KT  40 MPH
 12H  15/0000Z 19.8N 139.8W   30 KT  35 MPH
 24H  15/1200Z 20.2N 142.4W   30 KT  35 MPH
 36H  16/0000Z 20.4N 145.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  16/1200Z 20.6N 147.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  17/0000Z...DISSIPATED