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Tropical Depression Norbert Discussion Number  20
NWS National Hurricane Center Miami FL       EP192020
300 PM MDT Tue Oct 13 2020
 
Low pressure associated with the remnants of Norbert has become 
well-organized today, with persistent convection near and north of 
the estimated low-level center. Partial ScatSat and ASCAT-B passes 
near of this system suggest the low-level circulation is closed, 
and 25-30 kt scatterometer winds are noted in the northeast 
quadrant of the low. Additionally, earlier surface observations from 
Socorro Island, Mexico and ship observations from the Nathaniel B 
Palmer research vessel reported northwesterly winds on the backside 
of the system. Together, all this information supports the 
conclusion that the remnants of Norbert have redeveloped into a 
tropical depression. The initial intensity for Norbert is set at 30 
kt based on the recent ASCAT-B overpass and a T2.0 subjective 
Dvorak classification from SAB.

Norbert is only forecast to be a short-lived depression given the 
increasingly hostile environmental conditions it is expected to face 
during the next 24-48 h. While the vertical wind shear is currently 
weak, it is forecast to quickly increase by Wednesday courtesy of a 
mid- to upper-level low pressure system centered offshore of the 
Baja California peninsula. The majority of the guidance shows little 
or no intensity change, and the official NHC intensity forecast 
calls for Norbert to remain a 30-kt depression during the next 24 h. 
This should be followed by weakening as Norbert transitions to a 
remnant low by 48 h due to 20+ kt of deep-layer shear and decreased 
oceanic heat content. The remnant low is expected to dissipate by 
Thursday night.

Norbert is currently moving to the northwest at 11 kt. This general 
motion will continue for the next 24 h as the depression moves 
between a deep-layer ridge centered over northern Mexico and the 
upper low offshore of Baja California. As the upper low shifts 
westward, Norbert's forward speed will slow as the depression is 
drawn more northward before dissipation.  
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  13/2100Z 19.8N 111.7W   30 KT  35 MPH
 12H  14/0600Z 21.1N 112.8W   30 KT  35 MPH
 24H  14/1800Z 23.0N 114.3W   30 KT  35 MPH
 36H  15/0600Z 24.4N 115.3W   25 KT  30 MPH
 48H  15/1800Z 25.5N 115.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  16/0600Z...DISSIPATED
 
$$
Forecaster Reinhart/Cangialosi
 
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