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Hurricane Douglas Discussion Number  16
NWS National Hurricane Center Miami FL       EP082020
1100 PM HST Thu Jul 23 2020

Douglas continues to look impressive in satellite images, with a 
clear eye and symmetric convection in all quadrants. Broad outflow 
channels extend about 300 n mi in every direction from the cyclone, 
indicative of nearly zero wind shear. The latest Dvorak CI values 
from TAFB and SAB, as well as the recent UW/CIMSS ADT estimates  
are all T6.0, which supports keeping the initial advisory intensity 
at 115 kt. 
 
Douglas is crossing the 26 C isotherm, and will continue to move 
over relatively cooler waters of about 25 C over the next day or so. 
This should cause the cyclone to begin weakening very soon. In about 
48 h, Douglas is forecast to move back across the 26 C isotherm, but 
at the same time the cyclone is forecast to begin encountering a 
drier, more stable airmass and increasing vertical wind shear. 
Despite the warmer waters, these other more hostile environmental 
factors are expected to cause Douglas to gradually weaken for the 
remainder of the 5-day forecast period. The latest NHC forecast is 
changed little from the previous advisory, and is very close to a 
blend of the corrected consensus HCCA and the IVCN/ICON consensus 
aids.
 
Douglas is still moving quickly west-northwestward or 295/16 kt.
A mid-level ridge to the north of the cyclone should keep moving 
the cyclone in the same general direction over the next couple of 
days. Over the weekend, as Douglas approaches the Hawaiian Islands, 
a more westward motion is forecast as another ridge builds to the 
north of the cyclone. There is some notable spread in the model 
guidance now compared to yesterday as Douglas approaches the 
Hawaiian Islands. The faster and southernmost guidance from the 
ECMWF takes the center of the cyclone over the big island, while the 
northernmost GFS and HWRF take the cyclone just north of the island 
chain. The other guidance, including the track consensus aids lie in 
between those solutions. The latest NHC forecast was nudged 
slightly northward between 48 h and 96 h, but still remains south 
of the consensus aids during those time periods. Otherwise, the NHC 
forecast was little changed from the previous one.  

This is the last advisory issued by the National Hurricane Center
on Douglas.  Future information on this system can be found in
Forecast/Advisories issued by the Central Pacific Hurricane Center
beginning at 1500 UTC under AWIPS header HFOTCMCP2 and WMO header
WTPA22 PHFO.  For information specific to the Hawaiian Islands,
users should continue to consult products from the National Weather
Service Forecast Office in Honolulu, Hawaii, at www.weather.gov/hfo.
 
 
Key Messages:
 
1.  Douglas is expected to move near or over portions of the
Hawaiian Islands this weekend, and there is an increasing chance
that strong winds, dangerous surf, and heavy rainfall could affect
portions of the state beginning Saturday night or Sunday.
Interests on the Hawaiian Islands should continue to monitor the
progress of Douglas and the official forecasts as they evolve over
the next few days. Watches could be issued on Friday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 15.7N 140.3W  115 KT 130 MPH
 12H  24/1800Z 16.7N 142.6W  105 KT 120 MPH
 24H  25/0600Z 17.9N 145.7W   95 KT 110 MPH
 36H  25/1800Z 19.0N 148.7W   85 KT 100 MPH
 48H  26/0600Z 19.9N 151.7W   75 KT  85 MPH
 60H  26/1800Z 20.5N 154.5W   65 KT  75 MPH...NEAR HAWAII
 72H  27/0600Z 21.0N 157.1W   60 KT  70 MPH...NEAR HAWAII
 96H  28/0600Z 22.0N 163.2W   50 KT  60 MPH
120H  29/0600Z 22.4N 170.0W   45 KT  50 MPH
 
$$
Forecaster Latto
 
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