000 WTPA43 PHFO 050844 TCDCP3 Tropical Depression Twelve-E Discussion Number 4 NWS Central Pacific Hurricane Center Honolulu HI EP122019 1100 PM HST Wed Sep 04 2019 Latest conventional and microwave satellite images show that the depression's organization has changed little over the past 6 hours, with a somewhat elongated center producing spotty deep convection. Latest subjective Dvorak intensity estimates from PHFO/PGTW/SAB support maintaining an initial intensity of 25 kt for this advisory. The initial motion estimate for this advisory is an uncertain 260/7 kt, with the depression primarily being steered by a low-level ridge far to the north. The forecast anticipates that the depression will move generally west to west-northwest through the forecast period. An increase in forward speed is expected after day 3 as the cyclone moves south of a strengthening deep-layer ridge centered far north of the main Hawaiian Islands. Guidance continues to show a large spread beginning as early as 24-36 hours, likely due in part to the uncertainties in initial location and movement. The GFS/HWRF are outliers on the right hand side of the guidance envelope, with the other reliable models clustered farther to the south. The updated official forecast has been nudged southward of the previous, and represents a blend between the HCCA and ECMWF. Model guidance continues to indicate that the cyclone will be slow to organize, despite sufficiently warm SSTs and relatively low vertical wind shear along the forecast track. Dry air impinging on the circulation from the north may be an inhibiting factor, as well as the poorly organized initial structure. The updated intensity forecast has changed little from the previous, is close to the SHIPS and IVCN consensus, and anticipates that the cyclone will eventually become better organized. However, increasing vertical wind shear in the later periods may preclude strengthening to a hurricane. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 12.0N 142.3W 25 KT 30 MPH 12H 05/1800Z 11.9N 143.3W 30 KT 35 MPH 24H 06/0600Z 11.7N 144.9W 35 KT 40 MPH 36H 06/1800Z 11.6N 146.3W 40 KT 45 MPH 48H 07/0600Z 11.7N 148.0W 45 KT 50 MPH 72H 08/0600Z 12.7N 152.7W 50 KT 60 MPH 96H 09/0600Z 14.0N 158.5W 55 KT 65 MPH 120H 10/0600Z 15.5N 165.0W 55 KT 65 MPH $$ Forecaster Birchard