000 AXPZ20 KNHC 191003 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Jun 19 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 along 93W and north of 04N is moving westward at 10-15 kt. Scattered moderate isolated strong convection has begun to flare out ahead of the wave from 06N TO 11.5N between 94W and 99W. A tropical wave extends SW to NE from 114W to 110W between 04N and 16N, moving westward at 10-15 kt. Active convection continues tonight with this wave under favorable upper atmospheric conditions. Scattered to numerous moderate to strong convection is noted from 08N to 15N between 110W and 119W. A tropical wave is along 121W-122W from 05N to 15N is moving westward at 10 kt. Scattered moderate to strong convection continues from 08.5n to 13N between 120W and 124W. A weakening tropical wave with axis along 136W-137W from 06N to 14N is moving westward at 10 kt. Widely scattered clusters of showers and thunderstorms are associated with this wave in the vicinity of its axis, and this wave is expected to continues to weaken over the next 24 hours. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09.5N74W TO 09.5N87W TO 11.5N114W TO 11N131W. The ITCZ then begins from 09N135W TO beyond 08N140W. Outside of convection discussed above under the Tropical Waves section, scattered to numerous moderate to strong convective activity is occurring along the NW coast of Colombia and coastal waters of Panama N of a line from 07N84W TO 04N77W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Overnight scatterometer data showed gentle to moderate northwesterly winds across the offshore waters as a very weak high pressure continues over the area E of 128W. Recent altimeter satellite data confirms wave models guidance of 4 to 5 foot seas. Little change is expected through Thu morning before the ridge strengthens slightly late Thu into the weekend, allowing winds to increase modestly, and seas to build by about 1 foot. Low pressure over the Colorado River Valley will strengthen some toward the end of the week, and a surface trough will continue to extend from this low over Baja California. This will cause winds to increase over the northern Gulf of California at the end of the week. Some northwesterly swell will also build seas off Baja California Norte for the end of the week and into the weekend. Farther south, a weak tropical wave will move west across the southern Mexico offshore waters, with little impact on local weather, aside from enhancing overnight coastal showers and thunderstorms. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Overnight scatterometer data showed gentle W to WSW winds across the area south of the monsoon trough, and only moderate offshore gap winds across the Papagayo region. Winds across Papagayo are expected to have increased to around 20 kt during the past few hours and will peak around sunrise before diminishing to moderate this afternoon. Moderate cross-equatorial swell is dominating area seas, producing 5-6 ft seas well offshore and 4- 5 ft near shore. The tight pressure gradient between high pressure north of the Caribbean Sea and lower pressure through the tropics will support fresh to strong gap winds across the Gulf of Papagayo region this weekend. Seas will continues to be dominated by pulses of moderate cross- equatorial southwest swell. REMAINDER OF THE AREA... A 1034 mb high remains quasi-stationary well N of the area near 42N139W and extends S and SW into the tropics. Overnight scatterometer data showed fresh tradewinds to the south of the ridge, from about 10N to 19N, where seas are running 6-7 ft in mixed swell. The ridge remains blocked from building into the the waters E of 125W due to a weak surface trough extends from central California into the far NE waters. However this trough will shift east and weaken through Fri, and allow the ridge to build modestly to the Revillagigedo Islands by late Fri. Seas across the area N of 25N are running 8 to 9 feet in mixed N and NW swell, except to 10 ft along 30N. Little change in this sea state is expected through Fri before new N swell builds seas 8- 10 ft across the waters N of 25N between 120W and 130W. Moderate S to SW swell will continue to move into the tradewind belt for the next few days and maintain seas in the 6-7 ft range. Farther south, long-period cross-equatorial swell of 8 to 10 feet is impacting areas south of 05N and west of 100W. Seas are expected to remain at this level through early Thursday, before decaying. Another increase in southern hemispheric swell is expected in the area by this weekend. $$ Stripling