000 AXPZ20 KNHC 230923 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 631 UTC Sun Jun 23 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 0840 UTC. ...TROPICAL WAVES... A weak tropical wave reaching from the Pacific coastal waters of southern Costa Rica near 08N83W northward to the Caribbean coast of Nicaragua near 14N83W will continue to drift westward along the Pacific coasts of Costa Rica and Nicaragua through Sun. The wave may eventually encroach on a low pressure area possibly forming off southern Mexico in the next day or two. A tropical wave persisting off southern Mexico has an axis from 06N to 15N along roughly 98.5W. The wave is drifting west around 5 kt. Scattered showers and a few thunderstorms are ongoing east of the tropical wave axis in the area where southwest winds converge into the monsoon trough. Earlier scatterometer satellite data showed generally light winds on the northern periphery of the tropical wave, outside of showers and thunderstorms. A new area of more vigorous convection has begun to fire along the wave axis between 10N and 13N. Global model output continues to suggest a surface low pressure area will form near the tropical wave today or tonight, then drift WNW parallel the coast of Mexico through mid week. A tropical wave has an axis along 108W from 04N to 12N. It is moving westward between 15 and 20 kt. Numerous moderate and scattered strong convection has developed just ahead of the tropical wave axis in the vicinity of the of the monsoon trough axis from 08N to 11N between 111W and 115W. A tropical wave has it axis along 120W from 04N to 15N, moving westward around 10 kt. Recent scatterometer satellite data shows no clear surface impact from this wave, and no significant convection is associated with the wave as well. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pres 1009 mb near 10N75W to 08N79W to 10N91W to 12N107W to 09N127W. The ITCZ continues from 09N127W to beyond 07N140W. Numerous moderate and scattered strong convection is present from 06N to 08N between 76W and 82W and from 08N to 11N between 111W and 115W. Scattered moderate and isolated strong convection is ongoing elsewhere within 270 nm S and within 180 nm N of the monsoon trough axis E of 117W. Scattered moderate and isolated strong convection is found from 07N to 13N between 126W and 129W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Earlier scatterometer satellite data continued to show light to gentle winds off southern Mexico, and concurrent altimeter data shows seas of 4 to 6 ft, likely with a component of SW swell. But the relatively tranquil conditions may not persist. Developing deep convection over the waters S of Puerto Angel in the vicinity of a tropical wave suggests a broad area of low pressure is starting to develop in the area along the monsoon trough. This will be the main weather feature to monitor for the waters adjacent to southern Mexico through mid week as the low pressure develops and consolidates. If this scenario plays out, expect higher winds, building seas and increased coverage of showers and thunderstorms for the offshore waters from Punta Angel to Cabo Corrientes through mid week. Please see the latest Tropical Weather Outlook for the eastern Pacific on hurricanes.gov for details. Looking ahead, global models indicate strong to near gale force gap winds into the Gulf of Tehuantepec Wed night through Thu night in the wake of the developing low pressure. Farther north, a modest pressure gradient will support gentle to moderate winds and slight to moderate seas across the area. The developing low pressure may move near the Revillagigedo Islands later in the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate winds will continue for most areas, although pulses of fresh to strong NE to E gap winds will impact the Papagayo region through Thu night. Seas are being dominated by long period S to SW swell from the southern hemisphere. Recent altimeter satellite passes indicated seas of 5 to 7 feet adjacent to Central America, with seas of 6 to 8 feet noted along the coasts of Colombia and Ecuador. The swell will maintain seas in these areas for at least the next several days. A rather vigorous tropical wave located over the western Caribbean near 83W is triggering widespread clusters of moderate to strong convection across the offshore waters E of 92W. This activity will most likely be attended by strong gusty winds and locally higher seas through at least tonight. REMAINDER OF THE AREA... A 1034 mb high remains quasi-stationary well north of the area near 40N138W. A ridge extends SE from the high to the Revillagigedo Islands. To the south of the high, the pressure gradient between the ridge and lower pressure in the tropics is supporting moderate NE to E trades N of the ITCZ and W of 120W. Little change in the position of the high or the speed of trades is expected for the next several days. Prevailing seas in this area will generally run between 5 and 7 ft. Farther south, long-period cross-equatorial swell is maintaining waveheights of 8 to 9 ft to the south of 09N between 100W and 120W. This area of seas will begin to subside this evening. Waveheights to 10 ft are possible along and just to the south of 03.4S between 115W and 120W today. $$ CAM