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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
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.
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