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Tropical Depression Six-E Forecast Discussion Number 2
2018-06-28 04:34:16| National Hurricane Center (East Pacific)
Issued at 900 PM MDT Wed Jun 27 2018 000 WTPZ41 KNHC 280234 TCDEP1 Tropical Depression Six-E Discussion Number 2 NWS National Hurricane Center Miami FL EP062018 900 PM MDT Wed Jun 27 2018 Convection associated with the depression has become a little better organized since the previous advisory as there has been a general increase in banding over the northwestern portion of the circulation. Despite the increase in organization, Dvorak intensity estimates from both TAFB and SAB are still below tropical storm strength, so the initial intensity will remain 30 kt for this advisory. The depression is currently located within an area of moderate northeasterly shear, however, the shear is forecast to decrease over the next couple of days. During this time, the depression will be traversing warm water and gradual strengthening is anticipated. By the weekend, the system is expected to begin moving over cooler waters and into less favorable thermodynamic conditions which should halt further intensification. Cool water and a more stable air mass should result in weakening later in the period and the system is forecast to become a remnant low by day 5. It should be noted that the 18Z GFS forecasts a significantly stronger cyclone than the remainder of the global models and intensity guidance, and appears to be an outlier. Since the strength of the GFS vortex is used as a predictor in the SHIPS guidance, that intensity model also showed more intensification this cycle. For now, the NHC intensity forecast follows the more conservative LGEM, HWRF, and ECMWF-based SHIPS guidance, and is not too different than the previous official forecast. If other models trend toward the GFS solution of a stronger storm, the NHC forecast may need to be adjusted in future advisories. Satellite fixes indicate that the depression continues to move west-northwestward around 13 kt. The cyclone is located to the south of a mid-level ridge that extends westward from northern Mexico. This should keep the cyclone on a general west- northwestward heading during the next several days, however the system is forecast to slow down as the ridge weakens by the weekend. The track guidance is in fairly good agreement, except for the aforementioned GFS which takes a deeper cyclone farther northward as the ridge weakens. The NHC track forecast is near the various consensus models through 48 hours, but leans more toward the ECMWF and HWRF after that time. FORECAST POSITIONS AND MAX WINDS INIT 28/0300Z 13.6N 109.6W 30 KT 35 MPH 12H 28/1200Z 14.3N 111.5W 35 KT 40 MPH 24H 29/0000Z 15.2N 113.7W 40 KT 45 MPH 36H 29/1200Z 15.9N 115.7W 45 KT 50 MPH 48H 30/0000Z 16.5N 117.5W 50 KT 60 MPH 72H 01/0000Z 17.3N 120.5W 50 KT 60 MPH 96H 02/0000Z 18.8N 123.8W 40 KT 45 MPH 120H 03/0000Z 20.0N 128.0W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Brown
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