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HURRICANE AMANDA DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL EP012014
800 AM PDT MON MAY 26 2014
Amanda has changed little during the past 6 hours, including an
intermittent eye embedded within a ragged CDO feature containing
cloud tops colder than -70C. A blend of final T-numbers and current
intensity estimates from TAFB and SAB, and an ADT value of T6.3/122
kt, yields an average of 114 kt. Thus, the initial intensity of
Amanda has been lowered to 115 kt for this advisory.
Smoothing through the many fits and starts yields a 12-hour average
motion of 345/04 kt, which is used for the advisory motion.
Otherwise, there are no significant changes to the previous
advisory track or reasoning. Amanda is expected to move slowly
north-northwestward to northward between a broad mid-level trough
to its west and a weak subtropical ridge situated to its east over
Mexico for the next 72 hours or so. After which some slow erratic
motion is possible when the cyclone is expected to weaken into
a shallow system and become trapped within weak steering currents.
The global and regional models are in good agreement on this
developing scenario. As a result, the official forecast track is
essentially just an update of the previous advisory track, and is
close to the consensus model TVCE and the FSSE model.
The deep-layer vertical wind shear across Amanda is assessed at
around 25 kt by both the GFS-based SHIPS model and UW-CIMSS, and
these strong shear conditions are expected to continue for at least
the next 36 hours. As a result, steady to rapid weakening is
forecast to begin later today, especially if significant cold
upwelling develops beneath the slow-moving hurricane. The NHC
intensity forecast is similar to the previous advisory, and closely
follows the intensity consensus model IVCN.
FORECAST POSITIONS AND MAX WINDS
INIT 26/1500Z 13.2N 111.6W 115 KT 135 MPH
12H 27/0000Z 14.0N 111.9W 100 KT 115 MPH
24H 27/1200Z 14.9N 112.2W 85 KT 100 MPH
36H 28/0000Z 15.7N 112.4W 70 KT 80 MPH
48H 28/1200Z 16.1N 112.4W 55 KT 65 MPH
72H 29/1200Z 16.8N 112.1W 40 KT 45 MPH
96H 30/1200Z 17.1N 111.8W 30 KT 35 MPH
120H 31/1200Z 17.3N 111.8W 25 KT 30 MPH...POST-TROP/REMNT LOW