690 AXPZ20 KNHC 180951 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...TROPICAL WAVES... A tropical wave extends ALONG 89W from 04N to 15N, moving W at 10-15 kt. No convection is associated with the wave at this time. A surface to low level trough extends from 08N105W to 13N102W, moving W at 10-15 kt. This feature has emerged out of the mid latitudes over the SW N Atlantic, and has propagated SW across Central America into the eastern Pacific over the past several days. Scattered to numerous moderate to strong convection is observed near the trough, from 05N TO 13N between 100W AND 106W. A tropical wave extends along 115W-117W from 04N to 16N, moving W at 10-15 kt. Scattered to numerous moderate to strong convection is observed near the wave, from 07N TO 13N between 114W AND 120W. A tropical wave extends along 130W-131W from 04N to 15N, moving W at 5-10 kt. Isolated clusters of moderate convection are observed from 10N to 12N between 126w and 134w. This feature is becoming less defined in time and may be starting to dissipate. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N73W TO 10N85W TO 11.5N110W TO 11.5N123W. The ITCZ begins near 10.5N125W and continues to beyond 07N140W. Outside of areas previously discussed above, scattered moderate to strong convection is noted within 150 nm either side of the axis between 97W and 127W. ...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. Surface low pressure is expected to cover a rather expansive area over the southwestern United States and California through mid week, and extend a sharp surface trough into the area waters along 123W to the north of 25N. This will prevent the ridge from building fulling into the offshore waters and produce gentle to moderate winds through Wed before winds begin to freshen as the surface trough dissipates. Under this pattern, expect pulses of fresh to strong SW to W 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. Otherwise, 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... Strong tradewinds across the south central Caribbean are spilling across Central America and producing offshore gap winds from the Gulf of Papagayo region to El Salvador. This scenario is expected to continue across the Caribbean and will support fresh to strong gap winds across the Gulf of Papagayo during overnight hours through mid week, and again Fri night and Sat. Elsewhere, fairly tranquil wind 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 1032 mb high pressure centered near 41N141W southeastward to just west of the Revillagigedo Islands. Recent scatterometer data showed fresh trade winds south of the ridge from 11N to 18N west of 132W, where seas were 7-8 ft. Elsewhere, moderate to fresh NE to E winds prevail south of the ridge to the ITCZ west of 125W. Various altimeter satellite data 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 to 7-8 ft, and thunderstorm activity. Northerly swell related to a gale center off the Northern California coast well north of the region is moving in the waters north of 28N and west of 125W and will propagate southward through the remainder of the forecast period. Seas north of 27N and west of 126W will build to 8-9 ft Tue through late Wed. 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. $$ Stripling