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Tropical Storm Greg Discussion Number 27
NWS National Hurricane Center Miami FL EP072017
800 PM PDT Sun Jul 23 2017
Greg has changed little since the previous advisory, with the
cyclone still producing intermittent bursts of deep convection near
the center. Subjective and objective satellite intensity estimates
remain at T3.0/45 kt, so the initial intensity will remain
unchanged at 45 kt for this advisory.
Greg's initial motion estimate is 275/12 kt. No significant changes
to the previous forecast track were required through 72 hours. Greg
is expected to continue moving west-northwestward to westward for
the next 3 days while it skirts along the southern periphery of a
deep-layer subtropical ridge centered northeast of the Hawaiian
Islands. The small cyclone is forecast to weaken to a remnant low
around 72 hours, with the shallow system being forced
west-southwestward by brisk northeasterly tradewind flow. The new
NHC forecast track closely follows the TVCN consensus model.
Little change in strength is expected for the next 24 hours or so.
Gradual weakening is expected thereafter due to drier and more
stable air getting entrained into the cyclone, followed by
increasing vertical wind shear. By 72 hours and beyond, the shear is
expected to exceed 25-30 kt, which should result in Greg
degenerating into a remnant low. The new intensity forecast is
similar to the previous advisory, and closely follows the intensity
consensus model ICON and IVCN.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0300Z 14.4N 131.4W 45 KT 50 MPH
12H 24/1200Z 14.6N 132.9W 45 KT 50 MPH
24H 25/0000Z 15.0N 134.7W 45 KT 50 MPH
36H 25/1200Z 15.6N 136.2W 40 KT 45 MPH
48H 26/0000Z 16.4N 137.6W 35 KT 40 MPH
72H 27/0000Z 17.0N 140.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 28/0000Z 16.9N 143.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 29/0000Z 16.1N 146.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Stewart
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