000
WTPZ41 KNHC 270235
TCDEP1

HURRICANE AMANDA DISCUSSION NUMBER  18
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP012014
800 PM PDT MON MAY 26 2014

Amanda's cloud pattern had been reasonably well organized during
the day, with the cyclone maintaining a small Central Dense Overcast
and an intermittent but faint eye.  The eye has since disappeared
and the convective structure has become increasingly less symmetric,
presumably as a consequence of an increase in southerly vertical
wind shear.  The cloud pattern has also recently become elongated
poleward, with little to no outflow noted to the south. Using a
blend of Dvorak T- and CI numbers and recent satellite trends...the
advisory wind speed is reduced to 90 kt.

Center fixes indicate that Amanda has moved somewhat erratically
during the day...but smoothing through these yields an initial
motion of 340/04. The cyclone is embedded in a region of weak
steering flow between a mid-level ridge over the Gulf of Mexico
and a mid- to upper-level trough to the west.  This pattern should
steer the cyclone slowly northward during the next couple of days.
After that time, the forecast becomes more challenging as the
model spread increases significantly.  The GFS forecasts Amanda to
remain a deeper cyclone longer and therefore moves it much farther
northeast, while the ECMWF shows the cyclone decoupling sooner and
interacting with a disturbance to the its east.  As a result, Amanda
or its remnants in the ECMWF solution move generally eastward
without gaining much latitude.  Given the uncertainty, the official
forecast is close to the multi-model consensus TVCE and a little to
the east of the previous forecast beyond 36 hours.

Global models show the shear at its worst during the next 24 hours
and then slowly decreasing as the mid- to upper-level trough
affecting the cyclone lifts out.  Even though upper-level winds are
forecast to become anticyclonic late in the period...what remains of
the Amanda should be moving over cooler waters and within a region
of substantially drier and more stable air in the wake of the
aforementioned trough.  Thus, it would seem that the shear
debilitates Amanda and the other negative factors cause the cyclone
to degenerate into a remnant low.  The official forecast is lower
than the previous one and is a blend of the multi-model intensity
consensus ICON and LGEM.


FORECAST POSITIONS AND MAX WINDS

INIT  27/0300Z 13.7N 111.9W   90 KT 105 MPH
 12H  27/1200Z 14.2N 112.1W   80 KT  90 MPH
 24H  28/0000Z 14.9N 112.2W   65 KT  75 MPH
 36H  28/1200Z 15.4N 112.2W   50 KT  60 MPH
 48H  29/0000Z 15.9N 112.0W   35 KT  40 MPH
 72H  30/0000Z 16.5N 111.5W   30 KT  35 MPH
 96H  31/0000Z 17.0N 111.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  01/0000Z 16.9N 111.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Kimberlain