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Tropical Depression Ema Discussion Number 7
NWS Central Pacific Hurricane Center Honolulu HI CP012019
500 PM HST Sun Oct 13 2019
Satellite imagery over Ema shows a low cloud spiral with no nearby
deep convection. The latest subjective Dvorak intensity estimates
were 30 kt from HFO and 25 kt from JTWC. SAB found Ema to be too
weak to classify. An ASCAT-C pass showed maximum winds to 30 kt in
the east quadrant of Ema. I have kept the initial intensity for this
advisory at 30 kt.
The initial motion estimate for this advisory is 330/15 kt. Ema
continued to track northwest around 10 kt for much of the day. The
track has shifted further north over the past few hours, possibly in
response to a brief burst of convection northeast of the center.
With the tropical cyclone remaining shallow, the primary steering
mechanism will be surface high pressure to the north. Ema is near
the west end of a ridge extending southwest from a high near 35N
145W. A high near 40N 180W is forecast to move southeast over the
24 hours. Ema is forecast to turn toward the west as the western
high moves into position north of the low.
Strong southwest vertical wind shear is forecast to remain over Ema.
As a result, the latest forecast continues to show slow weakening of
the system during the next 24 hours. Ema is forecast to become a
post-tropical remnant low within 24 hours, followed by dissipation.
The pressure gradient between the remnant of Ema and the high to
the north will likely maintain an area of 25 kt winds even after
the low dissipates.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0300Z 23.4N 167.6W 30 KT 35 MPH
12H 14/1200Z 25.4N 168.8W 25 KT 30 MPH
24H 15/0000Z 28.0N 171.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 15/1200Z 29.0N 173.0W 25 KT 30 MPH...POST-TROP/REMNT LOW