Official Discussion issued by the National Hurricane Center

Chris (AL032018) DATA RELEASED: 7/9/2018 3:00:00 AM UTC

Copy of official data

Tropical Storm Chris Discussion Number  10
NWS National Hurricane Center Miami FL       AL032018
1100 PM EDT Sun Jul 08 2018

Chris is on a strengthening trend.  Deep convection has been
expanding over the center and recent microwave images show an
improved structure with tightly curved bands, especially on the
north and east sides of the circulation.  The NOAA Hurricane Hunters
are currently investigating Chris and so far they have found a
minimum pressure of 1005 mb and maximum flight-level winds of 57 kt,
which would support a 50-kt intensity.  The initial intensity is
increased to 50 kt, but this is a little lower than the latest
Dvorak estimates.

Chris has not moved much today as it remains caught in very weak
steering currents between two mid-level highs and a mid- to
upper-level trough to its northeast.  Since this pattern is not
expected to change much during the next day or so, Chris is likely
to continue to drift around during that time period.  On Tuesday,
however, a deep-layer trough is expected to approach the storm and
that should finally cause Chris to pull away to the northeast.  A
very fast northeastward motion is forecast toward the end of the
period when the cyclone becomes embedded in strong mid-latitude
flow.  The NHC track forecast is not too different than the previous
one and lies near the various consensus aids.

Additional strengthening is expected during the next 2 to 3 days as
Chris remains over the warm Gulf Stream waters and in a moderate
wind shear environment.  The global models suggest that Chris could
also benefit from baroclinic enhancements ahead of the approaching
trough.  The NHC intensity forecast follows the HCCA and ICON
models and brings Chris to hurricane strength on Monday with
additional strengthening into Tuesday.  Steady weakening should
begin shortly after 72 hours, and extratropical transition should be
complete by 96 hours when Chris crosses the north wall of the Gulf
Stream and is over very chilly 10 degree C waters.  The NHC
intensity forecast is slightly higher than the previous one during
the next few days to be in better agreement with the latest
guidance.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 32.5N  74.5W   50 KT  60 MPH
12H  09/1200Z 32.4N  74.5W   60 KT  70 MPH
24H  10/0000Z 32.3N  74.5W   70 KT  80 MPH
36H  10/1200Z 32.3N  74.5W   75 KT  85 MPH
48H  11/0000Z 33.5N  73.2W   80 KT  90 MPH
72H  12/0000Z 37.5N  68.2W   80 KT  90 MPH
96H  13/0000Z 43.6N  61.5W   55 KT  65 MPH...POST-TROP/EXTRATROP
120H  14/0000Z 49.5N  52.0W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Cangialosi