000 AXPZ20 KNHC 282047 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Jul 28 2021 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 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 2030 UTC. ...TROPICAL WAVES... A tropical wave with its axis along 92W extends from Chiapas to near 05N. It is moving westward at 10 to 15 kt. Scattered moderate to isolated strong convection is noted from 06N to 08N between 88W and 92W. A tropical wave has its axis along 107W from 03N to 15N, moving westward at 10-15 kt. Scattered moderate to isolated strong convection is from 09N to 13N between 100W and 107W. A tropical wave has its axis near 123W from 03N to 17N, moving westward at 10-15 kt. No significant convection is evident near this tropical wave. A tropical wave has axis along 136W/137W from 03N to 15N. It is moving westward at 10-15 kt. Scattered moderate to isolated strong convection is noted from 08N to 10N between 136W and 138W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N77W to 1008 mb low pressure near 11N107W to 09N113W to 1007 mb low pressure near 13N120W to 10N125W. The ITCZ continues from 10N125W to beyond 10N140W. In addition to the convection described in the Tropical Waves section above, scattered moderate to isolated strong convection is evident from 12N to 14N between 116W and 120W, and from 08N to 11N west of 127W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh north gap winds are pulsing across the Gulf of Tehuantepec, between relatively higher pressure to the north of the region and lower pressure farther south. Light to gentle variable winds are elsewhere with seas mainly to 3 to 5 ft. Farther north, a relatively weak pressure gradient supports gentle to locally moderate northwest winds over the Baja California offshore waters with seas in the 3 to 5 ft range in SW swell. For the forecast, high pressure north of the area and lower pressure farther south will support pulses of gap winds across the Gulf of Tehuantepec and off western Oaxaca tonight and Thu night. Mostly moderate winds and seas will persist elsewhere. Looking ahead, seas will build off southern Mexico starting late Sat due to increased southerly swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate south to southwest winds will remain south of the monsoon trough through the forecast period along with a southwest swell that will build seas to 5-7 ft. Moderate to locally fresh northeast to east winds will continue over the Papagayo region and waters downstream from there through Sun, then diminish slightly Sun night. Seas of 3-6 ft due to a southwest swell will change little over Gulf of Papagayo region during the next few days. For the forecast, fresh to strong gap winds may pulse tonight across the Gulf of Papagayo and again Thu night into Fri. Elsewhere, gentle to moderate south to southwest winds will dominate the waters south of the monsoon trough through the forecast period along with southwest swell. The weather over the offshore waters of Costa Rica and Colombia will be unsettled over the next few days due to instability associated with passing tropical waves. REMAINDER OF THE AREA... Scattered showers and thunderstorms continue near an area of low pressure centered along the monsoon trough near 13N119W. Light NW shear is evident, pushing the convection mainly to the southeast of the center. A recent scatterometer satellite pass showed this feature to be fairly elongated, with fresh to strong SW winds in the southeast quadrant, and fairly light to moderate winds on its northern periphery. This is due in part to a trough north of 25N along 125W which is weakening the subtropical ridge. There is a medium chance the low may develop into a tropical cyclone over the next five days at it tracks westward and becomes better organized. Even if it does not, expect strong winds and seas to 8 to 9 ft near this low pressure over the next several days. A second low pressure area is centered near 11N107W with an estimated pressure of 1008 mb. Showers and thunderstorms remain fairly disorganized east of the center along the monsoon trough. Recent scatterometer satellite data showed a few moderate to fresh NE winds on the north side of the low, but mostly gentle to moderate winds are evident and seas are likely no more than six feet near the low. Elsewhere, generally moderate NE trades persist north of the monsoon trough and moderate S to SW winds farther south, with 5 to 7 ft seas in mixed swell in most areas. Larger southerly swell is noted south of the equator. $$ Christensen