551 AXPZ20 KNHC 212109 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Aug 21 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 2015 UTC. ...TROPICAL WAVES... A tropical wave along 87W is moving W around 10 kt. Isolated moderate convection is from 05N to 11N between 83W and 89W. A tropical wave along 102W is moving W around 10-15 kt. Scattered moderate convection is from 05N to 13N between 98W and 111W. A tropical wave along 119W is moving W around 10-15 kt. Scattered moderate convection is from 07N to 15N between 116W and 128W. A tropical wave along 134W is moving W around 10-15 kt. Scattered moderate convection is from 10N to 16N between 132W and 140W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pres 1009 mb near 10N76W to 08N83W to 09N100W to 12N119W to 12N126W. The ITCZ begins near 12N126W and continues to 12N133W then resumes near 12N135W and continues beyond 12N140W. Scattered moderate convection is N of 03N E of 82W and from 07N to 15N W of 138W. For more information about convection see the tropical waves section. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge across the NE Pacific extending SE from a 1028 mb high centered near 41N142W covers the forecast waters N of 19N W of 118W. This ridge will support a weak to modest pressure gradient across the offshore waters of Baja California. Light to gentle NW winds are expected through Thu night before the ridge strengthens slightly and the pressure gradient tightens supporting then NW gentle to moderate winds along the Baja offshore waters. Seas will generally remain in the 3-4 ft range through Thu, then seas will increase to 5 ft over the offshore waters of Baja California Norte. Surface troughing over the Baja Peninsula will maintain a generally light wind regime over the Gulf of California through the weekend. Strong N to NE gap winds will affect the Gulf of Tehuantepec tonight through early Fri morning. Winds are forecast to peak near 30 kt each night. Seas will build to 8 ft during the day and increase to 9 ft at night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will linger between 08N to 12N during the next few days. Winds on both sides of the trough axis will generally be light to moderate. The main exception to this will be over the Gulf of Papagayo, where moderate to fresh offshore winds will pulse to locally strong each night. Seas are expected to remain 6-7 ft downstream of Papagayo during this time. REMAINDER OF THE AREA... Elsewhere, the pressure gradient between ridging across the northern waters and the ITCZ will support gentle to moderate trades and 4-7 ft seas in mixed swell N of the ITCZ and W of 120W through the weekend. Sea heights will be relatively low for most of the forecast area this week. Robust long period swell could arrive from the Southern Hemisphere toward the end of this week and cause seas near the Equator to begin building over the weekend. $$ Ramos