000 AXPZ20 KNHC 070934 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sun Aug 6 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ..TROPICAL WAVES... A tropical wave is along 101W/103W from 17N southward, moving west 10 to 15 knots. The 700 mb streamline analysis from the GFS model suggests that a trough is near the wave. Convective precipitation: scattered moderate to isolated strong from 15N to 17N between 98W and 102W, and from 07N to 10N between 100W and 104W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough passes through Nicaragua near 12N87W, to 11N96W, 12N102W, 11N115W, and 08N127W, and from 14N125W to 13N134W to 12N140W. Convective precipitation: scattered strong from 03N to 05N between 77W and 79W along the coast of Colombia, from 05N to 08N between 83W and 86W, from 11N to 12N between 85W and 87W in Nicaragua, within 60 nm to the north of the Monsoon Trough between 89w and 90W, from 15N northward to the coast between 94W and 95W including in the Gulf of Tehuantepec, within 90 nm to the north of the Monsoon Trough between 136W and 139W. Scattered moderate to isolated strong within 240 nm to the south of the Monsoon Trough between 89W and 97W, and within 120 nm on either side of the Monsoon Trough between 128W and 135W. Widely scattered moderate to isolated strong is elsewhere within 240 nm to the south of the Monsoon Trough between 100W and 123W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A 1011 mb low pressure center, that is the remnant of recent Tropical Depression Eleven-E, is centered near 20.5N 112.5W, nearly stationary. Satellite imagery shows a very well defined swirl of low clouds. The most current scatterometer data show that moderate winds are within 90 nm of the center in the NW semicircle. Light-to-gentle winds are within 90 nm of the center in the SE semicircle. The closed circulation is forecast to become a surface trough in 48 hours, by Wednesday, drifting SE in the area of the Revillagigedo Islands. A ridge will dominate the offshore waters to the west of northern and central Baja California. Expect gentle to moderate NW to N winds and seas in the range of 4 to 5 ft west of the Baja California peninsula. Gentle to locally moderate southerly flow will prevail across the Gulf of California. Gulf of Tehuantepec: the winds are forecast to be light-to- gentle in speed, and variable in direction, during the next several days. Wave model guidance has been suggesting consistently that a new set of long-period southerly swell, with the leading edge containing a period of 20 to 21 seconds, is forecast to reach the coast of Mexico south of Cabo Corrientes on Tuesday. This scenario will bring the potential for large breaking waves as it reaches shallow waters along the coast of Mexico on Tuesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The Gulf of Papagayo: expect light-to-gentle wind speeds during the next few days. Expect broad cyclonic wind flow for the first day or so, followed by sometimes variable and sometimes cyclonic wind flow for the following next few days. Sea heights will range from 4 feet to 5 feet during the first few days, and then from 5 feet to 6 feet for the next few days after that. Moderate southerly winds are expected to the south of the monsoon trough, with gentle and variable winds to the north of the monsoon trough, with seas generally in the 4 to 6 ft range. A set of long-period southerly swell, with a leading edge period of 20 to 21 seconds, is forecast to reach the coastal areas of Costa Rica and Panama late on Monday into early Tuesday, and then 6 to 12 hours later, reaching the coast of Mexico that is along 20N. The overall areal coverage of this period event will move northward, starting from 06N southward from 125W eastward, covering the waters that are between Ecuador and the Galapagos Islands at the start of the forecast period, and then end up being from 20N southward from 125W eastward by sunrise on Tuesday. The sea heights are expected to build to the range of 6 to 7 ft mainly over parts of the offshore waters on Tuesday, with some potential for large breaking waves as it reaches shallow waters along the coast. REMAINDER OF THE AREA... A surface ridge will build across the northern forecast waters. The remnant low pressure center of Tropical Depression Eleven-E gradually will become a trough by Wednesday, drifting SE. Moderate to locally fresh trade winds are expected around the southern periphery of the ridge and to the north of the convergence zone, mainly from about 12N to 20N and west of 125W, with associated seas in the range of 5 to 6 ft. A 1012 mb low pressure center is forecast to develop in the Monsoon Trough near 13N130W in about 24 hours or so. A second 1012 mb low pressure center is forecast to form near 12N137W in 24 hours also. The 13N130W low pressure center is expected to dissipate in 48 hours. The 12N137W low pressure center is expected to move near 12N139W in 48 hours. Neither low pressure center is expected to remain in the analysis by 72 hours, on Thursday. Model guidance is forecasting an event of 8 foot sea heights crossing 03.4S from 120W eastward on Friday evening in 5 days, and moving northward and reaching the Equator just after midnight on Sunday. $$ mt