ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Hurricane John Discussion Number 13 NWS National Hurricane Center Miami FL EP122018 300 PM MDT Wed Aug 08 2018 John has shown some improved organization since the last advisory as the system has formed a 20 n mi wide cloud-filled eye. Satellite intensity estimates remain in the 65-77 kt range, so the initial intensity will be held at 75 kt for this advisory. Other than this temporary break in the weakening, there is little change to the intensity forecast, as the forecast track takes John over progressively colder sea surface temperatures and into a more stable air mass. The new intensity forecast is in the center of the intensity guidance, with John expected to weaken to a tropical storm in 24 h or less and to a remnant low between 48-72 h. The initial motion is 325/13, a bit faster than earlier. A combination of an upper-level low near 19N 124W and a mid- to upper-level ridge over northwestern Mexico should steer John northwestward for the next 36 h or so. After that, the cyclone or its remnants is forecast to turn west-northwestward in the low-level trade wind flow. Near the end of the forecast period, a slow motion is expected as the remnants of John move into an area of light steering currents. The guidance envelope has shifted a little to the north from the previous advisory, and the new forecast track is north of and faster than the previous forecast. Although the center of John is forecast to remain well offshore of the Baja California Peninsula, a surge of moisture around John's outer circulation is expected to bring some locally heavy rainfall to portions of Baja California Sur during the next couple of days. Therefore, interests in the southern portion of the Baja California Peninsula should monitor the progress of John. John is also producing large swells that are already affecting portions of the coast of the southern Baja California peninsula. These swells are predicted to spread northward along the west coast of the peninsula today and reach portions of the coast of southern California by late Thursday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 22.0N 113.5W 75 KT 85 MPH 12H 09/0600Z 23.2N 115.0W 65 KT 75 MPH 24H 09/1800Z 24.6N 117.2W 55 KT 65 MPH 36H 10/0600Z 25.8N 119.3W 45 KT 50 MPH 48H 10/1800Z 26.7N 121.4W 40 KT 45 MPH 72H 11/1800Z 27.5N 124.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 12/1800Z 28.0N 126.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 13/1800Z 29.0N 126.0W 15 KT 15 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven NNNN
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Page last modified: Monday, 31-Dec-2018 12:10:43 UTC