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Tropical Storm DOUGLAS

Tropical Storm Douglas Discussion Number  33
NWS Central Pacific Hurricane Center Honolulu HI   EP082020
500 AM HST Tue Jul 28 2020

The low-level circulation center (LLCC) of Douglas remains exposed 
in infrared satellite imagery. The limited deep convection that 
remains is sheared well north of the center, due to persistent 
debilitating southwesterly vertical wind shear. With current trends, 
Douglas' time as a tropical cyclone appears to be limited. However, 
given that it was a strong category one hurricane just 24 hours 
ago, the cyclone is still producing tropical-storm-force winds over 
portions of the Papahanaumokuakea Marine National Monument as it 
spins down. Subjective Dvorak current intensity estimates ranged 
from 2.5/35 kt from HFO and SAB to 3.0/45 kt from PGTW, while a 
0746Z ASCAT pass detected winds up to 40 kt in the northern 
semicircle. Assuming some undersampling by the ASCAT, the initial 
intensity estimate for this advisory is 45 kt, with these winds 
confined to the northern semicircle. 

Now that Douglas is devoid of deep convection, the cyclone has 
accelerated, and the initial motion estimate for this advisory is 
290/16 kt. The LLCC is expected to continue moving quickly west- 
northwest to the south of a low- to mid-level ridge, while a low 
aloft to the west maintains the vertical wind shear. With deep 
convection unlikely to persist over the center of Douglas, 
dissipation is anticipated within 72 hours, with Douglas becoming a 
post-tropical remnant low within 48 hours at the latest. The updated 
track and intensity forecasts rely heavily on global model guidance 
that depict Douglas dissipating as it nears and crosses the Date 
INIT  28/1500Z 24.1N 166.6W   45 KT  50 MPH...NEAR FRENCH FRIGATE
 12H  29/0000Z 24.4N 169.4W   40 KT  45 MPH
 24H  29/1200Z 25.0N 173.4W   35 KT  40 MPH
 36H  30/0000Z 25.4N 177.5W   30 KT  35 MPH
 48H  30/1200Z 26.1N 178.4E   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  31/0000Z 27.6N 174.5E   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  31/1200Z...DISSIPATED
Forecaster Birchard