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Potential Tropical Cyclone Fourteen-E Discussion Number   4
NWS National Hurricane Center Miami FL       EP142017
900 AM MDT Wed Aug 30 2017

The potential tropical cyclone has not become any better organized
overnight, though available data indicate that the pressures
continue to fall and that the winds have increased to 30 kt.  It
appears that there are two centers in the broad circulation, and the
NHC position uses a mean center.  Only slow strengthening is
forecast today due to the disorganized surface circulation, but a
more significant intensification could start tomorrow.  If the
circulation consolidates, the upper-level winds and water
temperatures are very conducive to strengthening.  The NHC forecast
is similar to the previous one, just a bit above the model
consensus.  Because the system is forecast to be approaching
hurricane strength as it nears Baja California Sur, the hurricane
watch is maintained.  Later in the forecast period, the cyclone
should weaken while it traverses either land or the cooler waters
west of the Baja peninsula.

As before, with the lack of a definite center the initial motion is
quite uncertain, with the current estimate at 335/8 kt.  For the
next couple of days, the system/tropical cyclone is expected to move
slowly north-northwestward on the eastern end of a broad mid-level
cyclonic gyre.  In 3-5 days the motion should bend toward the
northwest and west-northwest due to a mid-level ridge to the north.
Model guidance has shifted a bit to the east today, and the official
forecast is adjusted in that direction.  A tropical storm watch has
been issued for the west coast of Mexico due to the changes in the
forecast.  Since the disturbance still lacks a well-defined center
and there is considerable spread in the model guidance, this
official track forecast has greater-than-usual uncertainty.

It is also important to note that very heavy rain causing
life-threatening flash floods and mudslides is possible over
portions of western Mexico and Baja California Sur.  Regardless of
exactly how strong the cyclone becomes, this is expected to be a
significant hazard.


FORECAST POSITIONS AND MAX WINDS

INIT  30/1500Z 19.3N 108.6W   30 KT  35 MPH...POTENTIAL TROP CYCLONE
 12H  31/0000Z 20.4N 109.2W   35 KT  40 MPH...TROPICAL STORM
 24H  31/1200Z 21.4N 109.6W   40 KT  45 MPH
 36H  01/0000Z 22.3N 109.9W   50 KT  60 MPH
 48H  01/1200Z 23.4N 110.4W   55 KT  65 MPH
 72H  02/1200Z 25.4N 112.3W   45 KT  50 MPH
 96H  03/1200Z 27.5N 115.0W   35 KT  40 MPH
120H  04/1200Z 28.5N 118.5W   25 KT  30 MPH

$$
Forecaster Blake

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