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Tropical Storm Flossie Discussion Number  19
NWS National Hurricane Center Miami FL       EP072019
500 PM HST Thu Aug 01 2019

Somewhat surprisingly, Flossie has become better organized this
evening.  Satellite images indicate that deep convection has become
more circular near the center, although the convection is still
favoring the eastern semicircle.  Microwave data also show that
a low-level eye feature is present again, so the initial wind speed
is raised to 60 kt, which is in good agreement with the CIMSS
satellite consensus.  The storm has a reasonable chance to become a
hurricane again overnight since shear is forecast to stay about the
same in the diurnal convective maximum period, in addition to the
cyclone moving over a warmer SST ridge during that time.  This
strengthening window should be short-lived with increasing
northwesterly shear in all of the model guidance, along with more
marginal water temperatures. Thus the new forecast is raised from
the previous one in the short-term, then basically matches the last
advisory after 36 hours and lies close to the model consensus.

Flossie continues to move west-northwestward or 285/16.  A large
subtropical ridge to the north is forecast to keep the storm moving
in the same general direction for the next few days, with some
reduction in forward speed over the weekend.  Thereafter, Flossie
reaches the southwestern periphery of the subtropical ridge, and
is anticipated to turn northwestward on Monday and northward on
Tuesday.  The model spread is similar to the previous cycle, but it
is notable that the regional hurricane models (HWRF, HMON,
COAMPS-TC) have shifted somewhat to the northeast on this cycle,
closer to the previous NHC prediction and model consensus.
Therefore, very little change is made to the last NHC track
forecast, except that it is faster, since the models have had a
tough time keeping up with the speed of Flossie.

It is worth noting that the confidence in the 4-day forecast
position of Flossie is still low, and the average error of track and
intensity forecasts at that range is about 150 miles and 20 mph,
respectively. In addition, hazards associated with tropical storms
extend well away from the center of circulation. Users should
therefore consult local forecasts from the National Weather Service
Forecast Office in Honolulu, Hawaii, at www.weather.gov/hfo for
information specific to the Hawaiian Islands.


FORECAST POSITIONS AND MAX WINDS

INIT  02/0300Z 16.4N 134.8W   60 KT  70 MPH
 12H  02/1200Z 16.9N 137.2W   65 KT  75 MPH
 24H  03/0000Z 17.5N 140.2W   60 KT  70 MPH
 36H  03/1200Z 18.1N 143.0W   55 KT  65 MPH
 48H  04/0000Z 18.7N 145.7W   50 KT  60 MPH
 72H  05/0000Z 19.7N 150.6W   40 KT  45 MPH
 96H  06/0000Z 22.5N 154.5W   35 KT  40 MPH
120H  07/0000Z 27.5N 155.5W   30 KT  35 MPH

$$
Forecaster Blake

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