000 AXPZ20 KNHC 090304 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 224 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Hurricane Aletta centered near 16.2N 112.3W at 09/0300 UTC or 170 nm SSW of Socorro Island moving WNW at 5 kt. Estimated minimum central pressure is 953 mb. Maximum sustained wind speed is 110 kt with gusts to 120 kt. Numerous moderate to strong convection is within 90 nm of the center. Scattered moderate isolated strong convection is noted elsewhere from 14N to 20N between 107W and 115W. Aletta is forecast to be impacted by increasing vertical shear and cooler seas surface temperatures, and will 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 11N97W. Scattered moderate to strong convection associated with this low is noted from 06N to 14N between 93W and 105W. Environmental conditions are favorable for this system to develop into a tropical cyclone this weekend. Since winds will reach gale force within 36 hours, a gale warning is 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 11N97W to 10N104W. It resumes from 10N119W to 07N129W. The ITCZ extends from 07N129W to 04N140W. Aside from convection associated with the low mentioned above, scattered moderate convection is noted from 05N to 10N between 116W and 126W and from 03N to 07N between 135W 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 new 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. This very large area of seas 8 ft or greater 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