Parts of the U.S. Government are closed. However, because the information this site provides is necessary to protect life and property, it will be updated and maintained during the Federal Government shutdown. For critical weather information, please visit www.weather.gov. To learn more, see www.commerce.gov.
Tropical Storm SERGIO
ZCZC MIATCDEP1 ALL TTAA00 KNHC DDHHMM Tropical Storm Sergio Discussion Number 2 NWS National Hurricane Center Miami FL EP212018 400 PM CDT Sat Sep 29 2018 Recent scatterometer data confirms that Sergio is at tropical storm strength, but with a slightly unexpected twist - the maximum winds are in a band about 110 n mi east of the center and there is no inner wind core at this time. The initial intensity remains 35 kt based on the scatterometer data. Sergio currently has good cirrus outflow in all directions, but there is some evidence that northerly upper-level winds below the level of the outflow are causing some light shear. Sergio is expected to be in an environment of light vertical shear and high humidity, and over warm sea surface temperatures for the next 3 days or so, which should result in steady strengthening. The environment is favorable enough for rapid intensification, although the current storm structure does not appear favorable for quick strengthening. The intensity forecast calls for gradual intensification during the first 24-36 h, with a faster rate from 36-72 h as the cyclone becomes better organized. Near the end of the forecast period, the storm may encounter increasing northeasterly shear which could limit intensification, and this is reflected in the forecast. The intensity forecast is in the middle of the guidance envelope and just above the intensity consensus, and the forecast may need to be adjusted upward in subsequent advisories. The wind radii forecast have been adjusted based on the current structure and the latest radii guidance. The initial motion is now 275/10. Sergio should be steered generally westward for the next three days or so by the subtropical ridge over Mexico. After that time, the cyclone should approach a weakness in the ridge caused by a large mid- to upper-level trough over California, and this should lead to a turn toward the northwest. The track guidance remains in good agreement with this scenario, and the new forecast track is similar to, but a little south of, the previous track. FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 12.1N 102.8W 35 KT 40 MPH 12H 30/0600Z 12.3N 104.3W 40 KT 45 MPH 24H 30/1800Z 12.3N 106.3W 50 KT 60 MPH 36H 01/0600Z 12.2N 108.3W 60 KT 70 MPH 48H 01/1800Z 12.1N 110.2W 75 KT 85 MPH 72H 02/1800Z 13.0N 114.0W 95 KT 110 MPH 96H 03/1800Z 15.0N 117.5W 95 KT 110 MPH 120H 04/1800Z 16.5N 119.5W 95 KT 110 MPH $$ Forecaster Beven NNNN