000 AXPZ20 KNHC 180330 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Nov 18 2016 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 0330 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec gale warning: a narrow swath of strong n to ne winds will continue to pulse across the Gulf of Tehuantepec through late Fri morning, then diminish briefly to a fresh breeze on Fri afternoon. A 20 to 25 kt northerly surge will begin around sunset Fri, with the winds quickly increasing throughout Fri night due to strengthening high pressure behind a strong Gulf of Mexico cold front, with the n flow reaching minimal gale force again late Fri night. Further strengthening will occur on Sat with strong gale conditions of 40 to 45 kt expected across a large swath late Sat night, with minimal storm force conditions winds a possibility although current guidance still indicates a 45 kt maximum near the surface. High profile vessels should expect storm force winds at 30 meters. Gale conditions will end late Mon night. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends wsw off the Pacific coast of northern Costa Rica at 10N85W TO 08N99W, then turns nw to 09N110W where a n to s orientated trough from 15N110W to 10N111W interrupts the monsoon trough. The monsoon trough resumes from 09N113W to 10N123W where scatterometer winds indicate an ITCZ forms, and continues sw to 09N126W, then turns nw to beyond 12N140W. Scattered moderate isolated strong convection is observed within 60 nm either side of a line from 08N98W to 11N105W, within 120 nm either side of a line from 14N101W to 10N110W to 06N116W, within 60 nm either side of a line from 15N114W to 09N124W and within 30 nm either side of a line from 13N129W to 14N134W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See special features section for a gale warning in the Gulf of Tehuantepec. The remnant circulation of former tropical cyclone Tina is still winding down near 19N113.5W and is estimated at 1011 mb. Moderate to fresh nw to n winds with combined seas of 7 to 11 ft are observed n of 22N w of the northern Baja Peninsula and southern California. These winds will diminish to a gentle to moderate n breeze on Fri, and light ne winds on Sat with the seas subsiding to 4 to 6 ft forecast w of Baja by late Sat. Large nw swell in the form of 7 to 9 ft seas will reach 30N120W on Sun morning, reach the n coast of the Baja Peninsula late Sun, extend s across all the offshore waters w of Baja on Mon night, then subside to less than 8 ft on Tue. Moderate to locally fresh nw winds will spread s across the entire Gulf of California tonight and continue through Fri before diminishing some on Sat. Expect light and variable winds on Sun. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to locally fresh ne winds are expected across and just downstream of the Gulf of Papagayo late each night through sunrise each morning for the next several days. The cyclonic circulation associated with a broad area of low pressure in the sw Caribbean is expected to produce a strong nocturnal n to ne flow across the Gulf of Papagayo late Sun night. Light to gentle n winds and combined seas of 3 to 6 ft are occurring elsewhere n of the monsoon trough which continues to meander e to w along about 09N, while moderate to locally fresh sw flow is observed s of the monsoon trough, with combined seas of 4 to 7 ft primarily in long-period sw swell. Little change forecast through the upcoming weekend. The conditions along the Pacific coast of Central America early next week are dependent on the strength and position of the the broad low pressure in the SW Caribbean that has the potential to become a tropical cyclone. REMAINDER OF THE AREA... Large nw swell resulting in combined seas of 7-11 ft are observed w of 115W and n of the monsoon trough and ITCZ. These seas will gradually subside to less than 8 ft on Sat. A cold front will move into the far nw waters tonight accompanied by a fresh to strong sw to w to nw wind shift to the n of 31N, and a 15 to 20 kt wind shift along the front elsewhere n of 28N. The front is forecast to reach a position from 32N130W to 21N140W on Fri night with the associated wind shift diminishing to 15 to 20 kt. The front should reach a position from 32N122W to 23N123W on Sun night, and weaken as it moves across the northern Baja Peninsula on Mon night. Another round of large nw swell will follow the front with seas of 8 of 16 ft initially, but subsiding to 7 to 10 ft by the time they reach the northern Baja Peninsula on Sun. $$ Nelson