000 AXPZ20 KNHC 111522 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1521 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 1200 UTC surface analysis and satellite imagery through 1415 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...Strong high pressure building southwestward over SE Mexico will tighten the pressure gradient across the Isthmus of Tehuantepec early on Wednesday continuing through Thursday afternoon. Strong northerly winds are forecast to begin late tonight and early Wednesday...then quickly increase to minimal gale force briefly on Wednesday morning. Gale force conditions are forecast to develop again on Wednesday night into Thursday morning. Expect seas to build to 10 to 12 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 axis extends from 07N90W to 06N96W to 04N105W to 05N128W to 01N140W. Widely scattered moderate from 02N to 07N between 87W AND 97W. Scattered moderate from 06N to 08N between 110W and 125W...and from 03N TO 06N between 128W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface ridge extends from NW to SE across the offshore waters to the W of 104W. Moderate to locally fresh anticyclonic winds are observed along the Pacific coast of Baja...with long period NW swell contributing to combined seas of 6 to 8 ft. The pressure gradient will tighten late tonight into early Wednesday with NW flow W of Baja California Norte increasing to fresh to strong. The strengthening winds along with fresh NW 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...gentle to moderate NW flow will become variable at light to gentle breeze levels through the day. These conditions 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 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 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. Sea 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 for the next several days. REMAINDER OF THE AREA... A cold front extends into the NW portion from 30N135W to 28N140W from a parent 996 mb low pressure system N of the area centered near 38N130W. Moderate to occasional fresh SW winds ahead of the front continue through this evening and will weaken gradually as the front weakens during the next 24 hours. Seas to 9 ft in NW swell are propagating eastward. As this front weakens...another front is forecast to arrive SE of 30N140W by Wednesday afternoon. Another set of NW swell with seas of 8 to 11 ft is expected to the W of the front Wednesday night through Thursday...decaying thereafter. Elsewhere...a ridge extends from 1022 mb high centered near 26N131W SE to near 16N110W. 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 ridging. Similar conditions are expected to prevail through the remainder of the week into the upcoming weekend. $$ HUFFMAN