Hurricane AMANDA

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HURRICANE AMANDA DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP012014
800 AM PDT SUN MAY 25 2014

Amanda has continued to rapidly strengthen this morning, although
the hurricane is likely near its peak intensity. The 15 n mi
diameter eye remains quite distinct in infrared and first-light
visible satellite imagery, and a solid ring of cloud tops as cold
as -75C surround the eye. Subjective classifications at 1200 UTC
from TAFB and SAB were T7.0/140 kt and T6.5/127 kt, respectively.
The ADT estimate from UW-CIMSS was T6.6/130 kt, and those values
have continued to steadily increase to T6.8/135 kt as of 1330 UTC.
A blend of these intensity estimates easily support increasing the
intensity to 135 kt, which is just below category 5 strength on the
Saffir-Simpson Hurricane Wind Scale.

Amanda appears to have stalled during the past few hours and is now
drifting slowly northward or north-northwestward at around 2 kt, a
motion that has been well forecast in previous advisories over the
past 2 days. Amanda is expected to maintain a general northward
motion over the next 72 hours as the hurricane moves into a
combined southerly steering between a mid-/upper-level trough to its
west and a mid-level ridge to its east. By days 4 and 5, Amanda is
expected to be a significantly weakened and more shallow cyclone
that is forecast to slow down and turn westward under the influence
of a large low-level subtropical ridge located from Baja California
westward into the central Pacific Ocean. The NHC track forecast is
similar to the previous advisory and lies near a blend of the FSSE
and TVCE models.

Amanda has likely reached its peak intensity, or is very close to
it. Although the SHIPS intensity model indicates SSTs warmer than
29C exists beneath and ahead of the hurricane, various SST analysis
products at 1200 UTC this morning indicate that cold upwelling has
already begun beneath the cyclone, and this cold upwelling should be
exacerbated even further now the cyclone is moving at a forward
speed of only 2 kt. As a result, steady weakening is expected within
the next 12 hours or so. By 36 hours and beyond, southerly to
southwesterly winds shear is forecast to increase to more than 20
kt, which should further enhance the weakening process. By day 5,
the global models are in good agreement on the low- and upper-level
circulations decoupling, which could result in Amanda becoming a
remnant low at that time. The official intensity forecast is similar
to the previous advisory, and closely follows the intensity model
consensus IVCN, which is well below the SHIPS and LGEM models
through 36 hours.

Amanda is now the strongest May hurricane on record in the eastern
Pacific basin during the satellite era. If Amanda were to reach an
intensity of 140 kt, it would become the earliest category 5
hurricane on record, beating out Hurricane Ava of 1973.

FORECAST POSITIONS AND MAX WINDS

INIT  25/1500Z 11.8N 111.1W  135 KT 155 MPH
 12H  26/0000Z 12.2N 111.3W  130 KT 150 MPH
 24H  26/1200Z 13.0N 111.4W  120 KT 140 MPH
 36H  27/0000Z 14.0N 111.6W  105 KT 120 MPH
 48H  27/1200Z 15.0N 111.7W   90 KT 105 MPH
 72H  28/1200Z 16.5N 111.5W   65 KT  75 MPH
 96H  29/1200Z 17.6N 110.7W   45 KT  50 MPH
120H  30/1200Z 18.6N 110.0W   30 KT  35 MPH

$$
Forecaster Stewart

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