000 AXPZ20 KNHC 082150 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1935 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Hurricane Aletta centered near 16.0N 111.7W at /2100 UTC or 170 nm SSW of Socorro Island moving WNW at 5 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 90 nm of the center. Scattered moderate isolated strong convection is noted elsewhere from 10N to 20N between 106W and 114W. Aletta is expected to maintain its intensity tonight. Aletta is forecast to be impacted by increasing vertical shear, and begin to weaken by tomorrow. 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. Surface low pressure has developed near 11N96W. Active convection associated to this low is noted from 06N to 14N between 92W and 100W. Environmental conditions are favorable for this system to develop into a tropical cyclone this weekend. Since winds will reach gale force within 48 hours, a gale warning has been issued. There is a high potential for this low to develop into a tropical cyclone during the next two days, and this warning may 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 0.5N84W to 09N86W to low pres near 11N96W to 11.5N103W. It resumes from 11N117W to 07N128W. The ITCZ extends from 07N128W to 05N140W. Scattered moderate isolated strong convection is noted from 06N to 14N between 92W and 100W. Scattered moderate convection is noted from 08N to 10N between 100W and 105W. Scattered moderate convection was noted from 08N to 10N between 114W and 125W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See above for more on Hurricane Aletta, as well as gale warnings associated with a newly developed 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 Sat. 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. 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 have increased 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 producing seas of 8 ft or greater south of a line from 08N132W to 08N107W to 00N100W. 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 much of the basin south of 24N between 100W and 130W by Sunday. Seas are expected to become chaotic in mixed swell as the weekend progresses, especially near Aletta. $$ AL