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Hurricane Olaf Discussion Number   8
NWS National Hurricane Center Miami FL       EP152021
900 AM MDT Thu Sep 09 2021
 
Recent microwave imagery shows that Olaf's structure has improved
considerably during the past 6 hours, and it now has well-defined
eye. The eye is also now evident in radar imagery from Cabo San
Lucas. Although an eye is not yet evident in infrared or visible
imagery, satellite intensity estimates had increased and supported
an intensity of 60-65 kt at 1200 UTC. Given the continued
impressive satellite appearance since then, the estimated intensity
is 65 kt for this advisory, making Olaf a hurricane.
 
Olaf has a microwave ring structure that is known to indicate
intensification in the short term. The wind shear that previously
affected the hurricane seems to have lessened and the environment
should also support further strengthening today. The hurricane is
therefore forecast to quickly intensify during the next 12 h or so
while it approaches the southern tip of the Baja California
peninsula. After that, interaction with land and cold sea surface
temperatures should cause the cyclone to quickly weaken over the
weekend. Olaf is forecast to become post-tropical in about 60 h as
it moves farther away from land. The NHC intensity forecast is
above the previous advisory, and is above most of the guidance
through 24 h. Beyond that, there have been only slight adjustments
to the official intensity forecast, which is based on the multi-
model consensus.
 
The track forecast has shifted closer to the southern Baja
California peninsula. In line with the intensity forecast, the NHC
forecast now slightly favors the stronger GFS and regional hurricane
models, compared to the weaker ECMWF, but is still near the HCCA and
TVCN consensus aids. Olaf is moving north-northeast but should turn
northwestward later today, steered by a mid-level ridge centered
over the western United States. The models with a stronger hurricane
show Olaf turning slightly slower, and bring the center very near or
even over Baja California Sur tonight. As Olaf weakens it should
begin to be steered by lower-level flow, which will cause it to
eventually turn westward and then southwestward as it moves away
from land early next week.
 
Key Messages:
 
1.  Olaf is forecast to pass very near or over the southern portion
of Baja California Sur tonight and Friday, and hurricane conditions
are likely within the hurricane warning area tonight. Tropical storm
conditions are expected to begin within the hurricane warning area
this afternoon, and preparations should be rushed to completion.
 
2.  Heavy rains associated with Olaf are expected across portions of
southern Baja California Sur through Friday. This will pose a threat
of significant and life-threatening flash flooding and mudslides.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/1500Z 21.2N 108.3W   65 KT  75 MPH
 12H  10/0000Z 22.2N 109.2W   75 KT  85 MPH
 24H  10/1200Z 23.3N 110.7W   65 KT  75 MPH
 36H  11/0000Z 24.0N 112.1W   60 KT  70 MPH
 48H  11/1200Z 24.1N 113.5W   45 KT  50 MPH
 60H  12/0000Z 23.8N 114.7W   35 KT  40 MPH...POST-TROPICAL
 72H  12/1200Z 23.2N 116.0W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  13/1200Z 21.5N 119.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  14/1200Z 21.0N 122.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster D. Zelinsky
 
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