412 AXPZ20 KNHC 112123 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2123 UTC Tue Jun 11 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...TROPICAL WAVES... A weak tropical wave is near 94W extending mainly south of 15N, moving west at 15 kt. Scattered moderate and isolated strong convection is occurring within 180 nm of the wave from 06N and 10N. A weak tropical wave is near 118W extending mainly south of 12N, moving west at 15-20 kt. Scattered moderate convection is occurring within 60 nm of the wave from 05N to 08N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from Costa Rica near 09N83W to 08N90W to 09W106W. The ITCZ extends from 09N106W to 07N117W, then continues from 06N120W to 10N134W. Scattered moderate and isolated strong convection is occurring within 180 nm of the monsoon trough between 86W and 93W, and within 300 nm north of the monsoon trough between 98W and 106W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a surface ridge over eastern Mexico and lower pressures associated with the monsoon trough is forcing strong to near gale force gap winds over the Gulf of Tehuantepec. Scatterometer data between 1530Z-1600Z today showed a swath of strong N to NE winds in the Gulf with fresh winds extending well downstream of the region. Combined seas likely remain near 10 ft in NE wind waves and S swell. The scatterometer passes also showed an area of stronger winds further south, likely associated with an earlier squall line based on satellite and lightning data. The Tehuantepec gap winds will diminish by Wed afternoon, then strengthen again Thu into early Fri. Elsewhere, a high pressure ridge west of Baja California will maintain gentle to moderate NW winds over the offshore waters through the upcoming weekend. Winds over the Gulf of California will generally remain light to gentle due to a weak pressure gradient for the next several days, with the exception of fresh nocturnal SW gap winds in the northern Gulf Thu night. A new set of long period SW swell will reach the southern Mexican offshore waters by Sat, but seas are expected to remain less than 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Nocturnal offshore flow will pulse to fresh speeds in the Gulf of Papagayo tonight as winds increase over the western Caribbean Sea. Winds will continue pulsing across the Gulf of Papagayo through the weekend with fresh speeds expected Thu night through Sun. Otherwise, fairly tranquil conditions will persist off Central America through the next several days under a weak pressure pattern. A new set of long period SW swell will reach the southern waters on Sat with seas likely building to 8 ft between Ecuador and the Galapagos Islands. REMAINDER OF THE AREA... A broad high pressure ridge persists across the northern waters with an axis roughly from 30N140W to 25N125W southeastward to beyond the Revillagigedo Islands. Partial scatterometer data this afternoon shows generally moderate to locally fresh trade winds south of the ridge and west of 130W. A weak trough near 138W will continue supporting locally fresh winds and combined seas to 8 ft through Wed night as it tracks westward beyond 140W. Otherwise, little change in winds or seas is expected through mid week. A new set of long period SW swell will reach the far SW waters by Thu night, then propagate NE across the region through Sat. Seas are expected to build to 8 ft or greater just south of the Equator by Fri night and persist through the weekend. No tropical cyclones are expected in the Eastern North Pacific basin for the next several days. $$ Reinhart