000 AXPZ20 KNHC 120241 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 139 UTC Wed Apr 12 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 0000 UTC surface analysis and satellite imagery through 0230 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 towards the morning hours. These conditions will quickly decrease to below gale-force after a few hours before pulsing back in the evening hours and through Thursday morning. Expect seas to build to 9 to 12 ft downstream of the gulf waters near 14.5N95.5W on Wednesday and Thursday mornings. The pressure gradient will relax on Thursday afternoon and fresh to strong northerly flow will pulse across the area through the week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 03N91W TO 04N132W. SURFACE TROUGH EXTENDS FROM 11N132W TO 03N133W. ITCZ RESUMES NEAR 03N134W TO 02N140W. SCATTERED MODERATE FROM 03N TO 09N BETWEEN 113W AND 131W. The Intertropical Convergence Zone extends from 03N91W to 04N132W. Surface trough extends from 11N132W to 03N133W. ITCZ resumes near 03N134W to 02N140W. Scattered moderate convection is from 03N to 09N between 113W and 131W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends from northwest to southeast across the offshore waters. With this, moderate to fresh anticyclonic winds prevail along the Pacific coast of Baja with long period northwest 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 9 ft. These conditions will persist through Friday before diminishing 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 near 7 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 to 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 26N140W. Moderate to occasional fresh southwest winds ahead of the front continue through the overnight hours and will weaken gradually as the front also weakens during the next 24 hours. Seas to 9 ft in primarily northwest swell are propagating eastward. As this front weakens, another front is forecast to approach the northern portion of the basin but weakening just 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 southeast while decaying. Elsewhere...a ridge extends from 1021 mb high centered near 26N130W southeast to near 18N110W. An area of moderate to fresh trades will develop overnight between 08N and 12N mainly west of 127W with seas to 9 ft.These winds will diminish by Wednesday morning. Moderate trades with seas to 8 ft prevail elsewhere within the southern periphery of the ridge. Similar conditions will prevail through the remainder of the week. $$ NATIONAL HURRICANE CENTER