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Post-Tropical Cyclone Vicky Forecast Discussion


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921 
WTNT41 KNHC 172039
TCDAT1

Post-Tropical Cyclone Vicky Discussion Number  15
NWS National Hurricane Center Miami FL       AL212020
500 PM AST Thu Sep 17 2020

There has not been any organized deep convection near the center of 
Vicky in more than 12 hours as very strong vertical wind shear 
continues to take a toll on the cyclone.  Vicky has become a swirl 
of low clouds and no longer meets the definition of a tropical 
cyclone.  Therefore, the system is being declared a remnant low and 
this will be the last NHC advisory on Vicky.  The Dvorak CI-number 
from TAFB suggests that the intensity of the system has fallen to 25 
kt, which is the basis for the advisory wind speed. Very strong 
vertical wind shear associated with outflow from Hurricane Teddy is 
expected to continue to cause the remnant low to weaken, and the 
system is expected to degenerate into a trough of low pressure in 24 
to 36 hours.  The official forecast follows suit and calls for 
dissipation by early Saturday.

Vicky is now moving west-southwestward or 250/10 kt. The remnant low
should remain on a west-southwestward heading while it is steered 
by the low-level northeasterly trade wind flow over the next day or 
so. The latest NHC track forecast is near the various consensus 
aids and in the middle of the tightly clustered dynamical models.

This is the last NHC advisory on Vicky. Additional information on 
the remnant low can be found in High Seas Forecasts issued by the 
National Weather Service, under AWIPS header NFDHSFAT1, WMO header 
FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php

FORECAST POSITIONS AND MAX WINDS

INIT  17/2100Z 21.1N  39.1W   25 KT  30 MPH...POST-TROPICAL
 12H  18/0600Z 20.6N  40.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  18/1800Z 19.9N  42.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 36H  19/0600Z...DISSIPATED

$$
Forecaster Brown