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Hurricane Douglas Discussion Number  17
NWS Central Pacific Hurricane Center Honolulu HI   EP082020
500 AM HST Fri Jul 24 2020
 
Douglas remains a powerful hurricane early this morning, although 
the satellite presentation has degraded quite a bit since last 
evening, with eye of the tropical cyclone now nearly completely 
cloud filled. The latest current intensity estimates from the 
satellite agencies came in with 5.5 (102 knots) from PHFO and SAB, 
5.0 (90 knots) from JTWC, while ADT came in at 5.9 (112 knots). 
Taking a blend of the estimates above and accounting for recent 
satellite trends, the intensity with this advisory will be lowered 
to 105 knots. Douglas continues to move rapidly to the 
west-northwest, with an initial motion set at 295/16 knots.

Hurricane Douglas recently moved over slightly cooler sea surface 
temperatures (SSTs) of around 78F, and this seems to have been 
enough to lead to the weakening seen in satellite imagery. Despite 
relatively low vertical wind shear values forecast to affect the 
tropical cyclone during the next couple days, SSTs will remain 
unfavorable for intensification. The official intensity forecast 
calls for steady weakening during the next couple days as Douglas 
nears Hawaii, with the cyclone expected to be a category 1 
hurricane or strong tropical storm approaching the eastern end of 
the state late Saturday night or Sunday. Continued weakening is then 
forecast as Douglas tracks westward over or near the other 
main Hawaiian islands and west of the state early next week. 
Depending on the amount of interaction with the high terrain of the 
Big Island and Maui, the tropical cyclone could weaken faster than 
indicated in the official forecast, which follows a blend of the 
corrected consensus and statistical model guidance.

Douglas is forecast to move rapidly off to the west-northwest 
during the next couple days toward a weakness in the sub-tropical 
ridge north of the Hawaiian islands. The subtropical ridge is 
forecast to strengthen north of the state over the weekend, and this 
should steer the tropical cyclone westward over or very near the 
Hawaiian Islands Sunday through Monday, before exiting to the west 
of the state. The official forecast continues to hug the southern 
end of the guidance envelope out of respect for the ECMWF, but if 
model trends continue, this track may need to be adjusted further 
northward in future advisory packages. 

Based on the latest intensity and track forecasts, Hurricane or 
Tropical Storm watches will likely be required for portions of the 
eastern end of the state (Big Island and the Maui County Islands) 
later today. 
  

Key Messages:
 
1.  Douglas is expected to move near or over portions of the main
Hawaiian Islands Sunday through Monday, and there is an increasing 
chance that strong winds, dangerous surf, and heavy rainfall could 
affect portions of the state beginning late Saturday night or 
Sunday. Interests on the Hawaiian Islands should continue to monitor 
the progress of Douglas and the official forecasts as they evolve 
during the next few days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 16.4N 141.9W  105 KT 120 MPH
 12H  25/0000Z 17.4N 144.3W   95 KT 110 MPH
 24H  25/1200Z 18.6N 147.5W   85 KT 100 MPH
 36H  26/0000Z 19.6N 150.4W   75 KT  85 MPH
 48H  26/1200Z 20.5N 153.4W   70 KT  80 MPH
 60H  27/0000Z 21.1N 156.1W   65 KT  75 MPH
 72H  27/1200Z 21.7N 158.8W   55 KT  65 MPH
 96H  28/1200Z 22.5N 165.0W   50 KT  60 MPH
120H  29/1200Z 23.5N 171.5W   45 KT  50 MPH
 
$$
Forecaster Jelsema
 
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