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HURRICANE OLAF DISCUSSION NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL EP192015
200 AM PDT MON OCT 19 2015
The overall satellite presentation of the hurricane has not changed
since the previous advisory. The ragged eye that was seen in the
last few visible satellite pictures has not become apparent in
overnight infrared images, but recent microwave data have indicated
the presence of a small well-defined eye. Objective and subjective
Dvorak satellite intensity estimates still support an initial wind
speed of 85 kt. Olaf is expected to remain over warm water and in a
low vertical wind shear environment during the next several days.
These factors favor intensification and Olaf is expected to become a
major hurricane during the next 12 to 24 hours. After that time,
some additional strengthening is forecast, but fluctuations in
intensity are likely due to eyewall cycles. The new NHC forecast is
unchanged from the previous advisory and is near the upper-end of
the intensity guidance, closest to the SHIPS/LGEM models. Some
gradual weakening is shown at days 4 and 5 when Olaf moves over
slightly cooler waters and into an area of drier mid-level air.
Recent satellite and microwave fixes show that Olaf is moving
westward or 280/10 kt. The track forecast reasoning remains
unchanged, as Olaf is expected to move around the southwestern
and western portions of a deep-layer subtropical ridge during the
next several days. The hurricane is forecast to turn west-
northwestward later today before it moves into the Central Pacific
basin tonight. A northwestward motion is expected in 2 to 3 days,
and a turn toward the north should occur late in the period when
Olaf nears a break in the ridge along 145W. The new NHC track is
similar to the previous advisory through 72 hours, but has been
adjusted westward at days 4 and 5 to be closer to the latest
multi-model consensus.
FORECAST POSITIONS AND MAX WINDS
INIT 19/0900Z 10.0N 136.4W 85 KT 100 MPH
12H 19/1800Z 10.3N 137.8W 95 KT 110 MPH
24H 20/0600Z 10.8N 139.6W 105 KT 120 MPH
36H 20/1800Z 11.4N 141.1W 110 KT 125 MPH
48H 21/0600Z 12.3N 142.5W 110 KT 125 MPH
72H 22/0600Z 14.3N 144.8W 110 KT 125 MPH
96H 23/0600Z 16.5N 146.0W 100 KT 115 MPH
120H 24/0600Z 19.0N 146.0W 85 KT 100 MPH
$$
Forecaster Brown
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