000
WTPA43 PHFO 042107
TCDCP3
 
Tropical Depression Twelve-E Discussion Number   2
NWS Central Pacific Hurricane Center Honolulu HI   EP122019
1100 AM HST Wed Sep 04 2019

The earlier burst of convection over TD 12E has faded, leaving a
rather ragged and elliptical looking system. Recent ASCAT data, the
subjective intensity estimates from PHFO, SAB, and JTWC, and the
UW-CIMSS ADT all suggest maintaining the depression at 25 kt.
It should be noted there is considerable uncertainty in the initial
position owing to the poor organization of the system currently.

The relatively shallow nature of the circulation is resulting in an
initial motion of about 255/8, as the depression is being steered
by relatively weak low level trade wind flow. Guidance is agreement
that a gradual turn toward due west is expected in a couple of days,
with a turn toward the west-northwest thereafter along with an
increase in speed as the system moves south of stronger, deep
subtropical ridging. There was a slight southward shift in the
consensus guidance for this forecast, so the official track has
been nudged a little to the south as well. Toward the end of the
forecast period, the system should start to move more quickly
toward a weakness that develops in the subtropical ridge north
of the Northwest Hawaiian Islands. 

Sea surface temperatures are above 28C along the forecast track of
12E and shear is relatively weak. The main inhibiting factor in the
short term appears to be the poor organization and shape of the
circulation, as well as some dry air impinging on the northern
periphery of the circulation. The guidance suggests gradual
strenghtening, and the official forecast does as well assuming the
depression can overcome the inhibiting factors. The official
forecast splits the difference between the slightly more aggressive
SHIPS guidance and the somewhat less agressive dynamical model
guidance.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/2100Z 12.7N 141.4W   25 KT  30 MPH
 12H  05/0600Z 12.3N 142.6W   30 KT  35 MPH
 24H  05/1800Z 12.0N 143.9W   30 KT  35 MPH
 36H  06/0600Z 11.8N 145.1W   35 KT  40 MPH
 48H  06/1800Z 11.9N 146.6W   40 KT  45 MPH
 72H  07/1800Z 12.7N 150.5W   50 KT  60 MPH
 96H  08/1800Z 14.0N 156.0W   60 KT  70 MPH
120H  09/1800Z 16.0N 162.0W   60 KT  70 MPH
 
$$
Forecaster R Ballard