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Post-Tropical Cyclone Douglas Forecast Discussion


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683 
WTPA42 PHFO 291452 CCA
TCDCP2

Post-Tropical Cyclone Douglas Discussion Number  37...CORRECTED
NWS Central Pacific Hurricane Center Honolulu HI   EP082020
452 AM HST Wed Jul 29 2020

A cluster of thunderstorms north of Douglas' center is producing an 
impressive amount of lightning this morning, but is not indicative 
of system reorganization. While these thunderstorms are indeed 
associated with Douglas' deteriorating circulation, they are removed 
from the center, and will soon be sheared away by persistent 
southerly vertical wind shear. Satellite imagery shows the exposed 
low-level circulation center becoming increasingly elongated, while 
an earlier ASCAT pass indicated little in the way of westerly flow 
in the southern semicircle. Douglas has degenerated into a post- 
tropical remnant low (and may already be an open wave) with maximum 
winds on the north side estimated to be near 30 kt.  

With Douglas' initial motion vector of 275/20 kt, associated 
hazards have moved west of the Papahanaumokuakea Marine National 
Monument, and the Tropical Storm Warning has been discontinued. A 
strong low-level ridge to the north will steer Douglas rapidly 
westward, with the remnant low expected to cross the International 
Date Line later today. As the remnant low rounds the ridge, it is 
expected to gain some latitude over the next 24 hours or so before 
dissipating, in line with global model guidance and the previous 
forecast.

This is the last advisory issued by the Central Pacific Hurricane 
Center on Douglas. Additional information on this system can be 
found in the High Seas Forecasts issued by the National Weather 
Service in Honolulu under AWIPS header HFOHSFNP and WMO header 
FZPN40 PHFO.


FORECAST POSITIONS AND MAX WINDS

INIT  29/1500Z 24.7N 175.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 12H  30/0000Z 25.0N 178.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
 24H  30/1200Z 25.9N 177.2E   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  31/0000Z...DISSIPATED

$$
Forecaster Birchard