000 AXPZ20 KNHC 040943 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Aug 4 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. ...SPECIAL FEATURES... A tropical wave is along 107W/108W from 20N southward. A 1010 mb low pressure center is along the tropical wave near 16N. The precipitation pattern appears to be comparatively more organized. Environmental conditions are expected to support some additional development for only another 24 hours or less, before becoming hostile by the weekend. This low pressure center and area of precipitation should move west-northwestward about 15 mph for the next few days. The latest Tropical Weather Outlook gives this low pressure a medium change of tropical cyclone formation during the next 48 hours. Fresh to strong E to SE winds and seas of 8 to 10 ft are noted from 15N to 18N between 102W and 105W. These marine conditions will continue to affect the offshore waters of the States of Michoacan and Colima through tonight. ..TROPICAL WAVES... A tropical wave is along 94W/95W from 17N southward, moving westward 10 to 15 knots. This wave will continue to move westward across the Gulf of Tehuantepec area tonight. Isolated moderate precipitation is from 06N to 09N between 91W and 99W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough passes through Costa Rica near 09N85W, to 07N95W, 09N100W, to a 1010 MB low pressure center that is near 16N107W, 11N116W, and 10N126W. The ITCZ continues from 10N126W beyond 10N140W. Convective precipitation: numerous strong from 03N to 08N between 76W and 79W along coasts of Colombia and Panama. Srcattered moderate to isolated strong within 120 NM on either side of the line that runs from 12N117W to 09N122W to 09N132W, and also from 08N to 11N from 137W westward. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section, for information about a 1010 mb low pressure center that is near 16N107.5W or a few hundred miles to the west-southwest of Acapulco, Mexico, A low level trough will meander across the Baja California Peninsula. A ridge will dominate the offshore waters W of Baja California producing gentle to locally moderate NW winds through the weekend, with combined seas of 4 to 6 ft primarily in mixed long period NW and cross-equatorial southerly swell. Gentle southerly flow will persist across the Gulf of California, except for moderate southerly flow expected to the N of 30N on Friday night and again on Saturday night. The Gulf of Tehuantepec: moderate to fresh northerly winds are expected late Friday night into early Saturday morning with the assistance of the drainage flow. A new set of long period southerly swell, with a leading edge period of 19 to 20 seconds, is forecast to reach the coast of Mexico south of Cabo Corrientes on Tuesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The Gulf of Papagayo: moderate to fresh nocturnal offshore winds are expected tonight into Friday morning with seas building to 6 ft. Moderate southerly winds are expected to the south of the monsoon trough. Gentle and variable winds N of the monsoon trough with seas generally in the 4-6 ft range. Additional pulses of cross equatorial long period southerly swell will continue to reach the area. A new set of long period southerly swell, with a leading edge period of 19 to 20 seconds, is forecast to reach the waters between Ecuador and the Galapagos Islands on Monday, and the coast of Central America on Tuesday. Seas are expected to build to 6-7 ft in parts of the offshore waters with this swell event. REMAINDER OF THE AREA... A surface trough is along 29N127W 27N131W. It is the remnant of Irwin. The trough is forecast to dissipate in 12-24 hours. A surface ridge will build across the northern forecast waters, after an active period of tropical cyclone activity. Moderate to fresh trade winds also are expected around the southern periphery of the ridge and to the north of the convergence zone, mainly west of 120W. The 1010 mb low pressure center from the map analysis of 04/0000 UTC has weakened and dissipated. A 1010 mb low pressure center is forecast to develop in 24 hours, near 11N133W. Expect 20 to 25 knot winds and seas to 8 feet, within 60 nm of the center in the N semicircle. The low pressure center will remain at 1012 mb, near 12N136W, at 48 hours, but with winds 20 knots or less and sea heights less than 8 feet. Convective precipitation: scattered moderate to isolated strong within 120 NM on either side of the line that runs from 12N117W to 09N122W to 09N132W, and from 08N to 11N from 137W westward. $$ mt