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Tropical Depression Eleven-E Forecast Discussion Number 1
2018-08-04 22:34:40| National Hurricane Center (East Pacific)
Issued at 400 PM CDT Sat Aug 04 2018 280 WTPZ41 KNHC 042034 TCDEP1 Tropical Depression Eleven-E Discussion Number 1 NWS National Hurricane Center Miami FL EP112018 400 PM CDT Sat Aug 04 2018 Satellite images indicate that the disturbance located over the far eastern Pacific has become significantly better organized throughout the day, with the formation of a well-defined low pressure center and deep convection organized in a distinct curved band. Based on these criteria, the system is being designated as a tropical depression, and the initial intensity is set at 25 kt in accordance with Dvorak estimates from TAFB and SAB. Because the system has congealed so quickly, the initial motion is uncertain but estimated to be 285/11 kt. The cyclone's future motion will ultimately be dictated by a large mid-tropospheric ridge to its north and its proximity to another disturbance located about 450 n mi to the west. A west-northwestward motion at a nearly constant speed is expected during the next 2-3 days due to the ridge. After that time, the cyclone could begin to slingshot around the northern side of the larger weather system to its west. Many of the track models are not handling the depression very well; the GFS barely depicts a surface low from the get-go, and the HWRF does not appear to be accounting sufficiently for the possibility of binary interaction. As a result, the NHC official track forecast matches the consensus of the ECMWF and UKMET, the only two models which appear to have a decent grasp on the situation. Although the depression will be moving over very warm waters of 29-30 degrees Celsius over the next 2-3 days, the upper-level wind environment may not be ideal due to possible outflow from the larger disturbance to the west. As a result, the official intensity forecast is not too aggressive and is essentially close to the ICON intensity consensus. Even though the ECMWF and UKMET were used for the track forecast, the two models disagree on the cyclone's ultimate demise. The ECMWF has the system absorbed by the other disturbance by day 4, while the UKMET keeps it distinct and holds it just beyond the forecast period. As a compromise, the official forecast shows dissipation or absorption by day 5, but the confidence in this forecast is low. Based on the forecast, tropical-storm-force winds are expected to remain offshore the coast of Mexico. However, only a slight deviation in the forecast track or an increase in size could bring those winds closer to the coast, and interests along the southern and southwestern coast of Mexico should monitor the progress of the depression. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 12.4N 95.0W 25 KT 30 MPH 12H 05/0600Z 12.9N 96.4W 30 KT 35 MPH 24H 05/1800Z 13.6N 98.3W 35 KT 40 MPH 36H 06/0600Z 14.3N 100.2W 40 KT 45 MPH 48H 06/1800Z 15.3N 102.4W 45 KT 50 MPH 72H 07/1800Z 18.3N 107.8W 50 KT 60 MPH 96H 08/1800Z 20.0N 114.0W 45 KT 50 MPH 120H 09/1800Z...DISSIPATED $$ Forecaster Berg
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