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Tropical Storm Adrian Discussion Number   4
NWS National Hurricane Center Miami FL       EP012017
1000 AM CDT Wed May 10 2017

Adrian's satellite presentation is less organized than yesterday,
with little evidence of convective banding features along with a
few bursts of deep convection to the north and northwest of the
estimated center.  Vertical cross-sections through the latest GFS
model analysis indicate a significant tilt of the vortex from
southeast to northwest with height.  This is consistent with
analyses from UW-CIMSS that show around 20-25 kt of mid-level
southeasterly shear across the tropical cyclone.  This disruption
of the vertical coherency of the system is likely one of the reasons
that Adrian has not strengthened much.  The current intensity is
held at 40 kt based on earlier scatterometer data, although the
latest Dvorak estimates and the disorganized cloud pattern suggest
it might be a little weaker.  The global models do not call for
Adrian to intensify over the next several days, but the
statistical/dynamical models still show the system becoming a
hurricane within 72 hours.  The official intensity forecast is a
little lower than the previous one and close to the latest SHIPS
prediction, and is of low confidence.

Even with high-resolution visible imagery, the center is difficult
to locate.  Based mainly on microwave and scatterometer fixes, the
initial motion estimate is a rather uncertain 315/6 kt.  A mid-level
ridge to the north of Adrian should induce a northwestward to
west-northwestward motion for the next several days.  Later in the
forecast period, the ridge is predicted to collapse, leaving the
tropical cyclone in a region of very weak steering currents.
Based on this expected evolution of the large-scale flow, the
official track forecast shows no motion by days 4 and 5.

FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 10.4N  92.7W   40 KT  45 MPH
 12H  11/0000Z 10.8N  93.2W   40 KT  45 MPH
 24H  11/1200Z 11.4N  94.1W   45 KT  50 MPH
 36H  12/0000Z 11.9N  95.1W   50 KT  60 MPH
 48H  12/1200Z 12.2N  96.0W   55 KT  65 MPH
 72H  13/1200Z 12.7N  97.0W   65 KT  75 MPH
 96H  14/1200Z 13.0N  97.0W   70 KT  80 MPH
120H  15/1200Z 13.0N  97.0W   70 KT  80 MPH

$$
Forecaster Pasch

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