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Tropical Storm Norbert Discussion Number  23
NWS National Hurricane Center Miami FL       EP192020
900 AM MDT Wed Oct 14 2020
 
Recent satellite imagery suggests Norbert is beginning to feel the 
effects of deep-layer shear and drier mid-level air associated with 
a mid- to upper-level low pressure system centered to its 
west-northwest. While Norbert still shows signs of organization, the 
deepest convection is now displaced to the north of the estimated 
center position. The advisory intensity is held at 35 kt this 
morning based on objective and subjective current intensity Dvorak 
estimates from UW-CIMSS, SAB, and TAFB. It is likely that Norbert 
has peaked in terms of its intensity. 

Norbert's estimated initial motion is 325/13 kt. The cyclone is 
moving northwestward between a mid-level ridge over northern Mexico 
and the aforementioned mid- to upper-level low. This motion is 
expected to continue for the next 24 h, with a gradual decrease in 
forward speed as the upper low pulls away from Norbert.  There is 
increasing spread noted in the model track guidance as the steering 
flow weakens between 24-48 h, but the general trend is for a 
slightly more northward motion during this time. Only minor 
adjustments were made to the official NHC track forecast, which 
remains close to the various consensus aids including TVCE and 
HCCA. 

Increasing deep-layer shear, drier mid-level air, and cooler 
sea-surface temperatures are expected to induce a weakening trend 
beginning later today, and Norbert will likely become a tropical 
depression this afternoon. The GFS simulated satellite imagery 
suggests Norbert will lose its deep convection within the next  
24-36 h, and the official NHC forecast shows the system degenerating 
to a remnant low before dissipation at 48 h.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  14/1500Z 23.1N 114.0W   35 KT  40 MPH
 12H  15/0000Z 24.4N 115.0W   30 KT  35 MPH
 24H  15/1200Z 25.6N 115.7W   25 KT  30 MPH
 36H  16/0000Z 26.6N 115.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  16/1200Z...DISSIPATED
 
$$
Forecaster Reinhart/Beven
 
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