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ZCZC MIATCDEP1 ALL TTAA00 KNHC DDHHMM Hurricane Sergio Discussion Number 38 NWS National Hurricane Center Miami FL EP212018 200 PM PDT Mon Oct 08 2018 Sergio still consists almost entirely of a solid ring of deep convection surrounding a very large eye. A pair of timely ASCAT passes from around 1800 UTC show that the hurricane wind field remains very symmetric with a large RMW. Although we wouldn't expect that instrument to capture the true magnitude of the hurricane's maximum winds, the data does suggest that the winds have decreased at least a little since this morning. UW-CIMSS SATCON values have also decreased, so the initial intensity is lowered slightly to 75 kt. The hurricane is moving very slowly northward, around 3 kt. There has been no change to the reasoning behind the track forecast and Sergio should still accelerate northeastward in a day or so, approaching the Baja California peninsula by the end of the week. Nearly all of the models have shifted a little toward the south beyond 24 h, and the NHC track forecast has been adjusted in that direction as well, but now lies just north of the multi-model consensus. In the short-term, Sergio is still forecast to gradually weaken while it moves very little and continues to upwell cold waters. Beyond 24 h, the hurricane should reach additional cooler waters to the north, which should cause additional gradual weakening. In general, the intensity guidance is forecasting Sergio to maintain its intensity a little longer than previously forecast, so the NHC intensity forecast has been adjusted a little higher at 48 h and 72 h. It's worth noting that the hurricane would likely maintain its intensity longer if it moves a little farther south over warmer waters, and any further adjustments southward to the track forecast could have implications on the intensity forecast. By Friday afternoon, the cyclone should have reached the Baja California peninsula and more rapid weakening should follow. Although the low-level center of Sergio will likely quickly dissipate after reaching mainland Mexico, its mid-level remnants and moisture will continue northeastward, potentially causing heavy rainfall across parts of the southwestern United States. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 15.7N 128.5W 75 KT 85 MPH 12H 09/0600Z 16.2N 128.1W 70 KT 80 MPH 24H 09/1800Z 16.9N 127.0W 70 KT 80 MPH 36H 10/0600Z 17.7N 125.4W 65 KT 75 MPH 48H 10/1800Z 18.9N 123.2W 60 KT 70 MPH 72H 11/1800Z 22.9N 118.0W 55 KT 65 MPH 96H 12/1800Z 28.0N 111.5W 40 KT 45 MPH 120H 13/1800Z 33.5N 102.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Zelinsky NNNN