000 AXPZ20 KNHC 081511 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1442 UTC Fri Jun 8 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Hurricane Aletta centered near 15.8N 111.2W at 1500 UTC or 180 nm S of Socorro Island moving W at 4 kt. Estimated minimum central pressure is 943 mb. Maximum sustained wind speed is 120 kt with gusts to 130 kt. Numerous moderate to strong convection is within 120 nm of the center. Scattered moderate isolated strong convection is noted elsewhere from 08N to 20N between 106W and 114W. Aletta is expected to continue to intensify during the next 12 hours, with its maximum winds reaching 125 kt with gusts to 150 kt later today. Aletta is then forecast to be impacted by vertical shear, and begin to weaken afterwards. 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. The axis of a tropical wave is near 97W north of 08N, moving west at 10 kt. Enhanced convection is associated with the wave and monsoon trough. The wave will move further west during the next 24 hours, with an area of low pressure expected to form along it near 10N98W on Sat. Environmental conditions will become favorable for this system to develop into a tropical cyclone this weekend. There is a high potential for development during the next two days. 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 11N85W to 11N87W to 12N93W to 12N96W. It resumes from 11N117W to 07N128W. The ITCZ extends from 07N128W to 06N140W. Scattered moderate isolated strong convection is noted from 07N to 15N between 92W and 99W. Scattered moderate isolated strong convection is noted from 08N to 10N between 99W and 105W. Scattered moderate isolated strong convection was noted within 120 nm S of the monsoon trough between 117W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See above for more on Hurricane Aletta. Elsewhere, A broad ridge W of the area will support moderate to fresh NW winds west of the Baja Peninsula through Sat. A new pulse of NW swell will reach the waters west of northern Baja California today. A tropical wave near 97W will move W across the western waters today accompanied by active convection and increasing winds. Low pressure is expected to form along the wave later today, with high potential for tropical development by Sunday night. 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. These winds increase in areal coverage later today as Aletta tracks generally west to northwestward. NW to N swell from strong northerly winds along the coast of California will increase seas to around 8 ft N of 28N between 117W and 122W today, then reach south to near 24N between 117W to 124W on Sat, with max wave heights to 9 ft. Long period cross-equatorial SW swell is producing seas of 8 ft or greater west of 100W. As the SW swell propagates northward and merges with swell associated with Aletta this weekend, a very large area of 8 ft or greater seas will expand to include almost all of the basin south of 24N between 100W and 135W by Sunday. Seas are expected to become somewhat chaotic in mixed swell as the weekend progresses, especially near Aletta. $$ AL