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Hurricane Douglas Discussion Number 10
NWS National Hurricane Center Miami FL EP082020
1100 AM HST Wed Jul 22 2020
Douglas's structure has continued to improve, with a more
well-defined eye becoming apparent in visible and microwave
satellite images. Subjective Dvorak intensity estimates from TAFB
and SAB range from T4.0/65 kt and T5.0/90 kt, while the latest
UW-CIMSS ADT is 4.0. Douglas's initial intensity is therefore
raised to 70 kt as a blend of the satellite estimates.
The hurricane has begun to gain some latitude, and the initial
motion is just north of due west, or 275/14 kt. The track forecast
reasoning has not changed since earlier this morning, with a
persistent mid-tropospheric ridge to Douglas's north expected to be
the main driving force for the entire 5-day forecast period.
Douglas is forecast to turn west-northwestward by this evening, and
then maintain that heading with some increase in forward speed
through day 4 as it approaches the Hawaiian Islands. A bend back
to the west is then expected at the end of the forecast period.
The new NHC track forecast lies right along the forecast path from
the previous advisory through 60 hours, although it has been
shifted slightly north on days 3-5 based on an overall shift of the
guidance envelope at those times. Confidence in the track forecast
at this stage is rather high.
Intensity-wise, low shear and sea surface temperature of 28-29C
favor continued strengthening, potentially at a rapid rate for the
next 24 hours. SHIPS, HCCA, and the Florida State Superensemble
all bring the intensity near or at major hurricane strength in
24-36 hours, which qualifies as rapid intensification. The NHC
intensity forecast is in line with these models and lies near the
upper bound of the guidance envelope given the favorable
conditions. Some weakening is expected to begin by 48 hours due to
cooler waters, but since vertical shear is not expected to increase
until around day 4, the weakening rate is likely to be gradual.
This forecast increases the chance that Douglas could maintain
hurricane intensity as it approaches the Hawaiian Islands, and all
interests on the islands should monitor the forecasts as they
evolve over the next few days.
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 and heavy rainfall could affect portions
of the state beginning on 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.
FORECAST POSITIONS AND MAX WINDS
INIT 22/2100Z 12.1N 130.9W 70 KT 80 MPH
12H 23/0600Z 12.7N 132.9W 85 KT 100 MPH
24H 23/1800Z 13.8N 135.8W 100 KT 115 MPH
36H 24/0600Z 15.1N 138.9W 100 KT 115 MPH
48H 24/1800Z 16.4N 141.9W 90 KT 105 MPH
60H 25/0600Z 17.6N 145.0W 80 KT 90 MPH
72H 25/1800Z 18.7N 148.0W 75 KT 85 MPH
96H 26/1800Z 20.0N 154.0W 65 KT 75 MPH...NEAR HAWAII
120H 27/1800Z 21.0N 160.0W 55 KT 65 MPH...NEAR HAWAII