000 AXPZ20 KNHC 090901 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0901 UTC Sat Jun 9 2018 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... Hurricane Aletta centered near 16.2N 112.7W at 09/0900 UTC or 180 nm SSW of Socorro Island moving WNW at 5 kt. Estimated minimum central pressure is 967 mb. Maximum sustained wind speed is 95 kt with gusts to 115 kt. Numerous moderate to strong convection is within 90 nm of the center. Scattered moderate convection is noted elsewhere from 14N to 20N between 109W and 115W. Aletta is being impacted by increasing vertical shear and cooler sea surface temperatures, and will continue to weaken over this weekend. Please refer to the latest NHC Forecast Advisory under WMO/AWIPS headers WTPZ22/MIATCMEP2, and the NE Pacific High Seas Forecast under WMO/AWIPS headers FZPN03/MIAHSFEP2 for the latest information on this system. Broad surface low pressure is centered near 11N100W. Scattered moderate to strong convection associated with this low is noted from 07N to 14N between 94W and 105W. Environmental conditions are favorable for this system to develop into a tropical cyclone this weekend. Since winds are expected to reach gale force in 24 hours, a gale warning remains in effect. Since there is a high potential for this low to develop into a tropical cyclone during the next two days, this warning may be changed to a tropical cyclone warning. Please refer to the latest NHC Tropical Weather Outlook under header ABPZ20/MIATWOEP for the latest potential for development on this system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N84W to low pres near 11N100W. It resumes from 10N118W to 07N129W. The ITCZ extends from 07N129W to 05N140W. Aside from convection associated with the low mentioned above, scattered moderate convection is noted from 06N to 11N between 112W and 119W and from 03N to 06N between 134W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See above for more on Hurricane Aletta, as well as a gale warning associated with a broad area of low pressure, which has the potential for tropical development this weekend. Elsewhere, a broad ridge W of the area will support moderate to fresh NW winds west of the Baja Peninsula through the weekend. A pulse of NW swell prevails west of northern Baja California, with seas greater than 8 ft. This swell will merge with swell generated by Hurricane Aletta west of the Baja Peninsula generating confused seas greater than 8 ft that will persist into early next week, possibly becoming reinforced next week by the developing special feature low pressure system. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh east winds will continue across and downstream of the Gulf of Papagayo through the period, becoming fresh to strong Sat night. The monsoon trough will meander across the forecast waters near 10N. REMAINDER OF THE AREA... The surface ridge extending across northern waters will slowly shift westward the next few days. Fresh trades will continue across the tropics to the south of the ridge. NW to N swell from strong northerly winds along the coast of California continues to support seas to around 8 ft N of 26N between 117W and 124W. This swell will combine with swell generated from Hurricane Aletta this weekend. Long period cross- equatorial SW swell is combining with swell propagating away from Hurricane Aletta and is producing seas of 8 ft or greater from around 15N, southward to the equator, between 100W and 130W. The SW swell is also combining with NE tradewind driven waves to produce seas of 8 ft from 15N to 25N W of 135W. The very large area of seas 8 ft or greater near and south of Hurricane Aletta will persist over the weekend while expanding northward to 24N through Sunday. Seas are expected to become chaotic in mixed swell as the weekend progresses, especially near Aletta. $$ Latto