496 AXPZ20 KNHC 180211 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 210 UTC Tue Jun 18 2019 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 0200 UTC. ...TROPICAL WAVES... A tropical wave axis extends north of 04N along 88W, moving W at 10-15 kt. No convection is associated with the wave at this time. A trough extends from 06N to 12N along 101W, moving W at 10 to 15 kt. This feature emerged out of the mid latitudes over the Atlantic, and has propagated across Central America into the eastern Pacific over the past several days. Numerous moderate to scattered strong convection is observed near the trough, from 06N to 12N between 100W and 102W. A tropical wave axis extends from 04N to 14N along 115W, moving W at 10 to 15 kt. Scattered moderate convection is evident from 07N to 13N between 110W and 118W. This wave is become less well defined as it moves westward. A tropical wave axis extends from 04N to 13N along 130W, moving W at 5 kt. No significant convection is observed. This feature also looks much less defined and may be starting to dissipate. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N78W to 10N125W. The ITCZ begins near 09N130W and continues to beyond 08N140W. Outside of areas previously discussed near tropical waves, no significant convection is observed at this time. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a high pressure ridge west of Baja California and a low pressure trough along the Baja California peninsula is maintaining moderate northwest to north winds across most of the adjacent offshore waters where seas remain in the 4-5 ft range. Winds and seas off Baja California will change little through next several days as the ridge remains over offshore waters. Surface low pressure is expected to cover a rather expansive area over the southwestern United States and along California through mid week as a sharpening mid to upper- level trough moves over those regions. This will allow gentle to moderate winds through late in the week, with pulses of fresh to strong gap winds into the northern Gulf of California Tue night and again late Fri. Northwest swell will move into the waters off Baja California later in the week. Light to gentle winds will persist farther south over Mexican offshore waters. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... An earlier scatterometer satellite pass showed fresh to strong winds through the Gulf of Papagayo. This was due to a tight gradient between high pressure north of the area and lower pressure through the tropics. This pattern will support fresh to strong gap winds through the Gulf of Papagayo during overnight hours through mid week, and again Fri night and Sat. Elsewhere, fairly tranquil conditions will persist off Central America under a weak pressure pattern. Long-period southwest swell propagating through the southern waters will build the waveheights to 9 ft between Ecuador and the Galapagos Islands through Tue. Wave model guidance suggests that new south to southwest swell will propagate through the southern waters west of 90W Tue night through Thu building waveheights there to a peak of 8 ft again before they begin to subside late on Thu. REMAINDER OF THE AREA... A ridge extends from 1030 mb high pressure centered near 37N140W southeastward through the Revillagigedo Islands. An earlier scatterometer pass indicated fresh trade winds south of the ridge from 15N to 20N west of 135W. Various altimeter satellite passes show seas generally 5 to 7 ft. A series of weak tropical waves will move across the deep tropical waters through Sat, occasionally supporting locally higher winds, seas, and thunderstorm activity. Northerly swell related to a gale center off the California coast well north of the region will move in the waters north of 28N and west of 125W from late tonight through the remainder of the forecast period. Farther south, long period southwest swell to 8 ft will move in to the waters south of 08N between 95W and 130W through Wed, before decaying below 8 ft by late Thu. Another round of reinforcing southwest swell will bring seas to 8 ft in the same area Fri and Sat. $$ Christensen