000 AXPZ20 KNHC 112137 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1916 UTC Tue Apr 11 2017 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 2130 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...The pressure gradient generated between the surface high over southeast CONUS and lower pressures over Mexico will strengthens tonight supporting gale-force winds funneling down across the Isthmus of Tehuantepec. These conditions will quickly decrease to below gale-force by Wednesday afternoon. Gale winds will pulse once again on Wednesday night into Thursday morning. Expect seas to build to 9 to 11 ft downstream of the gulf waters near 14.5N95.5W on Wednesday and Thursday mornings. The pressure gradient will relax slightly Thursday afternoon with fresh to strong northerly flow pulsing thereafter through Saturday. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Intertropical Convergence Zone extends from 05N91W to 04N110W to 05N128W. Surface trough extends from 08N130W to 03N130W. ITCZ resumes near 04N131W to 01N140W. Scattered moderate convection is from 04N to 07N and east of 93W. Another area of convection prevails from 04N to 09N between 118W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends from northwest to southeast across the offshore waters to the west of 104W. With this, moderate to fresh anticyclonic winds prevail along the Pacific coast of Baja with long period NW swell contributing to combined seas of 5 to 7 ft. The pressure gradient will tighten late tonight into early Wednesday with northwest flow of Baja California Norte increasing to fresh to strong. The strengthening winds along with fresh northwest swell will help to build seas to 7 to 9 ft. These conditions will persist through Friday before diminishing slightly into the weekend. In the Gulf of California...light to gentle variable flow will then prevail through the week and into the upcoming weekend with seas mainly 2 ft or less, except 2 to 4 ft across the southern gulf waters through tonight. In the Gulf of Tehuantepec...see the special features section above for details on an upcoming gale-force gap wind event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo...fresh to locally strong nocturnal drainage winds are expected to pulse through the week and into the upcoming weekend. The most significant winds are expected on Wednesday night when seas will also build to 8 ft downstream of the gulf waters. In the Gulf of Panama...moderate to fresh nocturnal northerly flow is expected during the overnight hours through the remainder of the week and into the upcoming weekend. Seas are expected to build into a range of 5 to 7 ft downstream of the gulf waters. Elsewhere...light to gentle winds and combined seas of 3 to 6 ft will prevail during the next several days. REMAINDER OF THE AREA... A cold front extends into the northwestern portion of the basin from 30N132W to 27N140W. Moderate to occasional fresh southwest winds ahead of the front continue through tonight and will weaken gradually as the front weakens during the next 24 hours. Seas to 9 ft in northwest swell are propagating eastward. As this front weakens, another front is forecast to approach the northern portion of the basin but weakening north of the area. Another set of northwest swell with seas of 8 to 11 ft is expected to enter the area north of 27N by Wednesday night through Thursday. This swell will progress east while decaying. Elsewhere...a ridge extends from 1022 mb high centered near 26N130W southeast to near 15N101W. Earlier scatterometer data showed fresh to strong trades across the west-central waters where seas are 9 to 10 ft, with surrounding moderate to fresh trades and 8 to 9 ft seas elsewhere within the southern periphery of the ridge. Similar conditions will prevail through the remainder of the week and into the upcoming weekend. $$ NATIONAL HURRICANE CENTER