WTPZ42 KNHC 081459 CCA
Hurricane Olivia Discussion Number 32...Corrected
NWS National Hurricane Center Miami FL EP172018
800 AM PDT Sat Sep 08 2018
Corrected initial intensity in the text from 70 to 75 kt.
Satellite images indicate that Olivia continues to slowly weaken.
The eyewall convection has warmed during the past several hours,
with some breaks noted in the northwestern quadrant. A blend of
the various intensity estimates gives a value of 75 kt for this
advisory. Olivia is forecast to stay a hurricane for the next
couple of days while the system is experiencing light shear,
balanced by very dry air aloft and marginal but warming SSTs.
While the forecast is flat-lined through 48 hours, don't be
surprised if the system's intensity fluctuates upward at times, as
many eastern Pacific cyclones have done so this season within a
marginal environment. After the weekend, most of the guidance
indicates that westerly shear should increase, which will likely
cause weakening while Olivia approaches the Hawaiian Islands. The
new intensity forecast is basically an update of the previous one
and is close to the consensus.
Olivia has turned westward and is moving 275/13. A building
subtropical ridge should steer the hurricane basically due westward
for the next couple of days, and the model guidance is in good
agreement during this time. Thereafter, a mid-level ridge over
Hawaii will impart some northerly steering flow on Olivia, which
should cause the cyclone to move west-southwestward toward the
main Hawaiian Islands. There isn't great agreement on how fast it
will turn, however, due to the forecast depth of Olivia. The
guidance generally indicates a stronger system will turn more
southwestward, like the GFS or UKMET solutions, while a weaker
system would have less of a turn, like the ECMWF or HWRF solutions.
The model consensus has barely budged since the previous advisory,
so little change has been made. Since the track seems to be
dependent on the intensity at long range, this isn't a particularly
1. Olivia is forecast to approach the main Hawaiian Islands from
the east early next week, but it is too soon to determine the exact
location and magnitude of any impacts. Interests in Hawaii should
monitor the progress of Olivia this weekend and use this time to
enact your hurricane action plan.
2. Do not focus on the exact track or intensity forecast, or any
specific landfall location, as errors can be large at extended time
ranges. Tropical storm or hurricane conditions could be felt
anywhere in the islands as significant impacts could extend well
away from the center.
FORECAST POSITIONS AND MAX WINDS
INIT 08/1500Z 21.4N 138.0W 75 KT 85 MPH
12H 09/0000Z 21.6N 140.1W 65 KT 75 MPH
24H 09/1200Z 21.7N 142.8W 65 KT 75 MPH
36H 10/0000Z 21.7N 145.2W 65 KT 75 MPH
48H 10/1200Z 21.7N 147.2W 65 KT 75 MPH
72H 11/1200Z 21.2N 151.0W 60 KT 70 MPH
96H 12/1200Z 20.2N 155.6W 55 KT 65 MPH
120H 13/1200Z 19.0N 160.5W 45 KT 50 MPH
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