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Tropical Depression Six-E Forecast Discussion Number 1
2018-06-27 22:34:42| National Hurricane Center (East Pacific)
Issued at 300 PM MDT Wed Jun 27 2018 000 WTPZ41 KNHC 272034 TCDEP1 Tropical Depression Six-E Discussion Number 1 NWS National Hurricane Center Miami FL EP062018 300 PM MDT Wed Jun 27 2018 Satellite images indicate that the low pressure area south of Manzanillo has become better defined during the day, with ample banding features to the north and west of the center. Thus, this system is declared a tropical depression, and the initial wind speed is set to 30 kt, which is based on an overnight scatterometer pass and a satellite estimate of 30 kt from TAFB. The center has not been particularly easy to track since it hasn't had a lot of continuity. Generally the overall system has been moving west-northwestward at about 13 kt, so that will be the initial motion. A mid-level ridge over Mexico extending westward into the eastern Pacific is expected to steer the depression generally west-northwestward for the next several days, with some gradual decrease in forward speed in a few days due to the ridge weakening. The biggest uncertainty in the model guidance appears to be in the shorter term, with several models indicating a northwestward motion could begin soon. That motion doesn't make sense with the west-to-east orientation of the ridge, so the official forecast is on the southern side of the guidance envelope and the model consensus. Moderate northeasterly shear is forecast to wane over the next few days, which should promote strengthening since the depression is over warm waters. However, this intensification could be tempered by marginal SSTs in 2 or 3 days, and an intrusion of drier mid-level air as suggested by the GFS/ECMWF models. Thus only a moderate amount of strengthening is forecast, and the official forecast is between the SHIPS model and the NOAA corrected consensus HCCA model. In about 4 days, the depression will likely be over rather marginal SSTs with nearby dry air. These conditions will probably kill off any remaining deep convection, causing the cyclone to degenerate into a remnant low by day 5. FORECAST POSITIONS AND MAX WINDS INIT 27/2100Z 13.3N 108.5W 30 KT 35 MPH 12H 28/0600Z 14.1N 110.2W 30 KT 35 MPH 24H 28/1800Z 15.1N 112.4W 35 KT 40 MPH 36H 29/0600Z 16.0N 114.4W 40 KT 45 MPH 48H 29/1800Z 16.6N 116.1W 45 KT 50 MPH 72H 30/1800Z 17.5N 119.0W 50 KT 60 MPH 96H 01/1800Z 18.5N 122.5W 40 KT 45 MPH 120H 02/1800Z 19.5N 126.5W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Blake
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