000 AXPZ20 KNHC 161011 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Aug 16 2016 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 0830 UTC. ...TROPICAL WAVES... A tropical wave is along 95W-96W north of 08N, moving slowly westward near 10 kt. Very active convection continues to the east and northeast of this wave as described below between 87W and 97W. This active weather will shift westward today across the Tehuantepec region and tropical waters to the south. A tropical wave is along 105W-106W from 09N TO 17N, also moving slowly westward near 10 kt. Widely scattered to scattered moderate to strong convection associated to this wave was noted mainly near the monsoon trough between 104W and 112W. Global models suggest a broad low pressure area will gradually develop from this wave during the next few days as it shift west to west-northwest. A third tropical wave is near 126W from 10N to 19N, with an associated 1008 mb surface low center near 15.5N126W. Convection has diminished overnight associated with this lowcenter, and was generally located along the monsoon trough in that area as described below. Overnight scatterometer data showed a zone of 15-20 kt NE winds occurring across the NW quadrant of the low extending about 180 nm from the low center, where seas 6-7 ft prevailed. The wave and low are expected to continue to shift westward near 15 kt and gradually weaken, as environmental conditions are becoming less conducive for further development of this system. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N74W to 09N85W to 14N103W to 11N116W to low pres 1008 mb near 15.5N126W to 11.5N133W to beyond 13N140W. Scattered moderate to strong convection was noted from 06N to 10N east of 85W. Scattered to locally numerous moderate to strong convection noted from 06N to well beyond 16N between 88W and 97W. Scattered moderate to strong convection noted within 180 nm N and 210 nm S of trough between 98W and 114W. Scattered moderate to strong convection noted within 90 nm N and 180 nm S of trough between 124W and 139W. ...DISCUSSION... N of 15N E of 120W: The NE Pacific ridge extends southeastward into the area to near the Revillagigedo Islands. The pressure gradient between the ridge and a surface trough over Baja California is supporting moderate northwesterly winds over the coastal waters of Baja California Norte, while light to gentle northwest to west winds generally extends from Punta Eugenia to offshore of Cabo Corrientes. Seas continue in the 4-6 ft range across this area in mixed NW and SW swell. Light and variable winds prevail inside the Gulf of California. Little change in these overall marine conditions are expected during the next few days, with winds increasing modestly each late afternoon and evening along the Baja peninsula due to day time heating. S of 15N E of 120W: Gentle to moderate east to southeast winds generally prevail north of the monsoon trough from the Papagayo area to the Gulf of Tehuantepec area, then are gentle south to southeast from Tehuantepec to Cabo Corrientes as indicated by overnight scatterometer data. Gentle to moderate south to southwest winds prevail south of the monsoon trough. Seas are running in the 4-6 ft range in southwest swell across much of this area, but area 6- 8 ft south of the monsoon trough between 101W and 113W, where southwesterly winds are around 15 kt. Very active convection persists early this morning behind the tropical wave along 96W- 97W, and extends across southeast Mexico and into the Bay of Campeche. The trough has begun to lift northward to along 14N west of Tehuantepec in response to the tropical wave along 105W, and will lift slightly further to 15N along 110W by late tonight. Monsoonal southwest winds are expected to increase to 15-20 kt west of 95W during this time, with seas building to 7-9 ft. Light to moderate offshore winds will generally prevail across the Papagayo region through Wednesday. Southwest southern hemispheric swell will cross the equator and move into the area waters this morning and raise seas south of 04N to 6-8 ft through Wednesday. W of 120W: High pressure of 1029 mb centered near 40N139W extends a ridge southeast to near the Revillagigedo Islands. The pressure gradient between this area of high pressure and low pressure within the monsoon trough is producing moderate to fresh trades roughly from 13N to 22N west of 125W, where seas are in the 6-9 ft range. Gale force winds off the west coast of the United States will generate a northerly swell that will propagate into the north waters by late tonight into Wednesday. $$ Stripling