000 AXPZ20 KNHC 170336 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 336 UTC Wed Jun 17 2020 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 0300 UTC. ...TROPICAL WAVES... A tropical wave is along 89W-90W, moving west at 10 kt. Scattered moderate to isolated strong convection is noted from 08N to 10N within 150 nm west of the wave axis along the monsoon trough. A tropical wave is along 101W-102W, moving west 5-10 kt. Scattered moderate to isolated strong convection is ongoing from 08N to 11N between 90W and 93W. A tropical wave is analyzed along 121W, moving west around 10 to 15 kt. This wave well represented in low level satellite derived wind fields and lower level precipitable water fields also. The wave shows up well because it is interacting with an upper low situated to its northwest. Scattered moderate convection is active within 90 nm west of the wave axis from 09N to 11N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 09N110W to 11N118W to 10N130W. The ITCZ continues from 10N130W to beyond 09N140W. Scattered moderate to isolated strong convection is noted from 07N to 11N between 88W and 95W. Scattered moderate to isolated strong convection is noted from 08N to 13N between 105W and 113W. Scattered moderate convection is noted from 08N to 13N between 120w and 125W, and from 08N to 10N west of 130W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong northerly gap winds may again be pushing into the Gulf of Tehuantepec this evening, squeezed between lower pressure over the southwest Gulf of Mexico and the higher terrain over southern Mexico. The lower pressure has been enhanced over the past couple of days by a mid to upper level trough extending across the region from the northeast Gulf of Mexico. This mid to upper trough is dampening out, so the pattern will change through tomorrow and the gap winds will taper off. There may be a brief and limited gap wind event tomorrow night as well as the pattern transitions. Seas may reach 8 ft downstream of the Gulf of Tehuantepec, mixing with longer period southerly swell. Looking ahead, gentle to moderate breezes will persist in Tehuantepec through most of the remainder of the week. Brief pulses of fresh gap winds may return by late Sat. Farther north, a deep layer west of the area is building eastward following a sharp trough now extending from the southern Rockies through the central part of the Baja California peninsula into the open Pacific to 22N130W. This is tightening the gradient enough at the surface to support brief pulse of fresh to strong gap winds into the northern Gulf of California overnight. The gradient will relax again through the morning as the ridge continues to build eastward. Meanwhile NW swell producing seas of 7 to 8 ft in the outer offshore waters of Baja California Norte will subside tonight, before another pulse of NW swell to 8 ft will enter the waters northwest of Guadalupe Island by through late Wed. Looking ahead, moderate to fresh NW winds are possible off Baja California Sur by late week as a ridge builds into the area. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate SW monsoon flow prevails south of the monsoon trough, with gentle to moderate winds to the north of the monsoon trough. Seas are in the 5-7 ft range, mainly south of Panama. This will subside through mid week, but another round of SW swell is expected later in the week. REMAINDER OF THE AREA... A ridge extends from 1033 mb high pressure centered near 37N142W E-SE to the Revillagigedo Islands. The pressure gradient between this area of high pressure and lower pressure in the vicinity of the ITCZ is supporting fresh trade winds from 10N to 20N west of 125W. Seas are in the 7 to 9 ft range over this area in a mix of swell. Moderate to fresh winds, and seas of 5 to 7 ft, prevail elsewhere north of the monsoon trough/ITCZ. Moderate southerly flow prevails south of the monsoon trough/ITCZ. Long-period southerly swell still dominates the waters south of 10N and east of 110W, with 6 to 8 ft seas prevailing. Another round of southerly swell will enter the area late in the week. $$ Christensen