000 AXPZ20 KNHC 032128 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1931 UTC Thu Aug 3 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... A tropical wave is analyzed along 104W/105W north of 11N with a 1009 mb low pressure near 15N104.5W. Shower and thunderstorm activity associated with this wave has become more organized during the morning hours. Experimental GOES16 indicates that a surface circulation may also be forming. Environmental conditions are expected to support some additional development for the next day or two, before becoming unfavorable by the weekend. This disturbance should move west-northwestward at 10-15 kt during the next few days. Fresh to strong E to SE winds and seas of 8 to 10 ft are noted from 15N to 17.5N between 101W and 105W. These marine conditions will continue to affect the offshore waters of the States of Guerrero and Michoacan through this evening. ..TROPICAL WAVES... A tropical wave is N of 06N along 91W/92W moving west at 10-15 kt. This wave will continue W reaching the Gulf of Tehuantepec area tonight. Isolated moderate convection is ahead of the wave axis from 08N to 12N between 92W and 94W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 07N78W to 06N90W to 07N96W, then resumes from 13N103W to 1010 mb low pressure near 12N112W to 10N124W to 1009 mb low pressure near 09N133W to 09N137W. The intertropical convergence zone axis extends from 09N137W to beyond 09N140W. Scattered moderate moderate convection is elsewhere from 10N to 16N between 102W and 115W. Similar convection is from 07N to 10N W of 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see Special Features section for information on a low pressure located near 15N104.5W or a few hundred miles southwest of Acapulco, Mexico. Otherwise, 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 moderate southerly flow expected to the N of 30N on Friday night and again on Saturday night. In 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... In the Gulf of Papagayo, moderate to fresh nocturnal offshore winds are expected tonight into Friday morning with seas building to 6 ft. Otherwise, moderate southerly winds are expected S of the monsoon trough axis and 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 coasts of Central America on Tuesday. Seas are expected to build to 6-7 ft in parts of the offshore waters. REMAINDER OF THE AREA... The remnant low of Irwin remains near 28N131W. A swirl of low clouds is still noted in association with this feature on visible satellite imagery. The remnant low of Irwin is forecast to dissipate in about 24 hours. Then, a ridge will finally build across the northern forecast waters, after an active period of tropical cyclone activity. Moderate to fresh trade winds are also expected around the southern periphery of the ridge and north of the convergence zone, mainly west of 120W. A weak low pressure of 1009 mb is along the monsoon trough near 09N133W. Scattered moderate convection is noted within about 120 nm west semicircle of the low center. Marine guidance suggests increasing winds of 20-25 kt and building seas of 8-10 ft on the east of the low by tonight. The low will move W of the area by late Friday. $$ GR