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Tropical Depression Five-E Discussion Number 1
NWS National Hurricane Center Miami FL EP052018
800 PM PDT Sat Jun 23 2018
Over the past several hours, the low pressure system located around
115W has developed a well-defined surface circulation. The
convective pattern has also improved, with a primary band wrapping
around the western semicircle of the cyclone, and a secondary band
to the southeast and south. The system has therefore been
designated as Tropical Depression Five-E with an initial intensity
of 30 kt based on the latest TAFB Dvorak classification.
Although the lack of deep convection in the northeast quadrant
suggests that some moderate easterly wind shear and dry air are
present, warm SSTs below the cyclone will likely support slight
slight strengthening for the next 24 to 36 hours. The depression is
forecast to cross a sharp SST gradient and become embedded within a
far more stable environment on Monday. This should cause it to lose
all deep convection and gradually spin down as a remnant low through
the middle of next week. The NHC forecast conservatively shows the
system as a tropical cyclone through 72 h, but it could become a
remnant low sooner than that. The official intensity forecast is
very similar to the intensity consensus IVCN, and the model guidance
is in good agreement that only modest strengthening will occur over
the next day or two.
The depression has been moving generally northward and the initial
motion estimate is 355/8 kt. The dynamical models are in good
agreement that the shallow cyclone will move continue moving
northward for the next 24-36 h, steered by a weak low to mid-level
cut-off low to its west. After that time, the weakening system
should become increasingly steered by the low-level tradewind flow,
causing it to turn toward the around day 4. The official forecast
lies near the middle of the tightly clustered guidance envelope and
closely follows the track consensus TVCN.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0300Z 14.3N 115.7W 30 KT 35 MPH
12H 24/1200Z 15.6N 115.8W 35 KT 40 MPH
24H 25/0000Z 17.4N 116.3W 40 KT 45 MPH
36H 25/1200Z 18.7N 117.3W 40 KT 45 MPH
48H 26/0000Z 19.5N 118.4W 35 KT 40 MPH
72H 27/0000Z 20.3N 121.3W 30 KT 35 MPH
96H 28/0000Z 20.5N 125.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 29/0000Z 20.0N 129.5W 15 KT 15 MPH...POST-TROP/REMNT LOW
$$
Forecaster Zelinsky
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