ZCZC HFOTCDCP2 ALL
TTAA00 PHFO DDHHMM
 
Tropical Storm Flossie Discussion Number  26
NWS Central Pacific Hurricane Center Honolulu HI   EP072019
1100 AM HST Sat Aug 03 2019
 
The satellite presentation of Flossie remains unimpressive this
morning. Limited deep convection remains displaced to the northeast
of the partially obscured low-level circulation center. Subjective
current intensity estimates range from 2.0 at SAB to 2.5 out of JTWC
and HFO. These inputs, as well as CIMSS ADT, suggest an intensity of
35 kt, at best. However, successive ASCAT passes have revealed
stronger winds, with the latest from around 1900 UTC showing that
winds are at least 40 kt. Thus, the initial intensity will be
conservatively lowered to 45 kt.

High clouds are thinning over the low-level circulation center,
which will give higher confidence in Flossie's motion today. Based
on overnight microwave passes and recent GOES imagery, the initial
motion is set at 285/11 kt, which represents a slight deceleration.
During the next 48 hours, Flossie is expected to be steered
west-northwestward by a low- to mid-level ridge to the north.
Thereafter, a turn toward the northwest and a loss of forward speed
are expected, as the ridge weakens and Flossie interacts with an
upper-level trough parked north of Hawaii. The forecast track was
altered little from the prior advisory through 48 hours and was
nudged to the left on days 3 and 4. This change places the forecast
track closer to TVCN but still keeps it toward the right side of the
guidance envelope closer to the better performing ECMWF. 

There will be a small window for Flossie to maintain intensity
today, but by tonight, increasing vertical wind shear will lead to
weakening. Flossie will be traversing under the upper-level ridge
axis today, which could produce a brief period of enhanced outflow,
and with SSTs remaining around 26.5C, convection could flare up near
the center. Flossie will move north of the upper-level ridge axis
tonight and begin to encounter increasing southwesterly vertical
wind shear. The wind shear will increase to more than 30 kt by
tomorrow and will remain in place throughout the forecast period,
leading to steady weakening of Flossie. The intensity forecast is
essentially an update of the prior forecast and now weakens Flossie
to a remnant low on day 3. The forecast closely follows IVCN and
HCCA and weakens Flossie at a slightly slower rate than SHIPS and
LGEM.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/2100Z 18.8N 144.5W   45 KT  50 MPH
 12H  04/0600Z 19.2N 146.2W   45 KT  50 MPH
 24H  04/1800Z 19.7N 148.3W   40 KT  45 MPH
 36H  05/0600Z 20.0N 150.6W   35 KT  40 MPH
 48H  05/1800Z 20.6N 152.8W   30 KT  35 MPH
 72H  06/1800Z 23.1N 156.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  07/1800Z 25.4N 158.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  08/1800Z...DISSIPATED
 
$$
Forecaster Wroe
 
NNNN