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Tropical Storm Kenneth Forecast Discussion Number 4
2017-08-19 10:39:59| National Hurricane Center (East Pacific)
Issued at 200 AM PDT Sat Aug 19 2017 000 WTPZ43 KNHC 190839 TCDEP3 Tropical Storm Kenneth Discussion Number 4 NWS National Hurricane Center Miami FL EP132017 200 AM PDT Sat Aug 19 2017 Microwave data reveal that Kenneth is not well organized yet with the low- and mid-level centers well separated. The low-level center is located on the northeastern edge of the convection due to northerly shear as diagnosed by the SHIPS model. The overall outflow pattern is well established. A partial ASCAT pass around 0500 UTC and Dvorak estimates indicate that the initial intensity remains at 35 kt. The shear is forecast to decrease a little, and Kenneth will be moving over warm waters for the next two days. On this basis, the NHC forecast calls for some strengthening, and Kenneth could become a hurricane by Sunday. By the end of the forecast period, the cyclone is expected to be moving over cooler waters and weakening should then begin. The best estimate of the initial motion is toward the west-northwest or 285 degrees at 14 kt. The cyclone is embedded within the flow around the subtropical high, and this track should continue for the next day or two. After that time, Kenneth should have reached the western end of ridge, and it should then gradually turn more to the northwest or north-northwest. For the next 2 to 3 days, the track guidance is pretty tightly clustered, increasing the confidence in the forecast. Beyond 3 days, the forecast is less certain since the guidance spread is large. The NHC forecast is in the middle of the guidance envelope which is bounded by the ECMWF on the west side and by the GFS and the HWRF models on the right. The official forecast does not depart much from the previous one during the first 3 days, and is shifted a little bit to the right thereafter. FORECAST POSITIONS AND MAX WINDS INIT 19/0900Z 15.6N 120.2W 35 KT 40 MPH 12H 19/1800Z 16.0N 122.3W 45 KT 50 MPH 24H 20/0600Z 16.6N 125.0W 55 KT 65 MPH 36H 20/1800Z 17.5N 127.5W 65 KT 75 MPH 48H 21/0600Z 18.5N 129.5W 65 KT 75 MPH 72H 22/0600Z 20.5N 131.5W 65 KT 75 MPH 96H 23/0600Z 23.5N 132.5W 50 KT 60 MPH 120H 24/0600Z 26.5N 133.5W 40 KT 45 MPH $$ Forecaster Avila
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