000 AXPZ20 KNHC 020238 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Oct 2 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough axis extends from 09N84W to 08N89W to 09N94W to 09N100W to 13N110W. It resumes at 12N120W to 09N130W to 10N140W. Scattered moderate isolated strong convection is within 120 nm south of the axis between 130W and 135W. Scattered moderate convection is within 180 nm south of the axis between 107W and 110W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak pressure gradient remains over the forecast waters, and is supporting mainly light to gentle northwesterly winds across much of the area. Northerly winds of strong intensity through the Gulf of Tehuantepec will occur in a narrow swath into Sunday morning as high pressure over northeast and central Mexico ridges slightly southward, and interacts with broad low pressure south of the Gulf of Tehuantepec. These winds will diminish on Sunday afternoon, then are expected to pulse back up as strong northerly winds late Sunday night, and diminish on Monday afternoon. A surface trough extends from 21N116W to low pressure near 19N116W 1011 mb to 16N116W. An Ascat pass from Saturday afternoon showed a weak cyclonic circulation consisting of gentle to moderate winds, about 300 nm in diameter, associated with the low. Seas are generally 5-6 ft outside the Gulf of California, and 2 ft or less across all but the southern entrance to the Gulf of California. The surface trough and low will continue to slowly move westward through Sunday, then become steered in west- southwest direction with the anticyclonic low-level flow around the southeast periphery of the sub-tropical ridge that extends northwest to southeast across the northwest and north-central waters. The trough and low will gradually dissipate through Monday evening while the sub-tropical ridge builds east- southeast and strengthen. This will tighten the pressure gradient just to the north of the far northeast waters through by Monday with northwest to north strong to near gale force winds just north of 30N. Strong northwest to north winds are presently forecast to seep into the far northeast waters of the area by Sunday evening within 120 nm to the west of the Baja California Norte peninsula with seas in the range of 8 to 10 ft. The associated NW swell will propagate as far south as 26N from between Baja California Norte and 121W on Monday with resultant seas up to 9 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light and variable winds are expected north of the monsoon trough, while gentle to locally moderate south to southwesterly winds are expected south of the monsoon trough through Monday. Combined seas of 4 to 7 ft, primarily in long-period southwesterly swell is expected across the offshore waters into early next week. REMAINDER OF THE AREA... A large upper anticyclone dominates the area east of 135W, while broad upper troughing is over the area west of 135W. As stated above, the aforementioned sub-tropical ridge will strengthen over the northern portion through Monday. The pressure gradient between the ridge and lower pressure within the monsoon trough region will tighten. This will freshen winds north of the monsoon trough early next week, with winds increasing to moderate to fresh intensity from 15N to 25N west of about 120W. The long fetch of these fresh trades will help build seas to the 7-9 ft from Sunday afternoon into Monday. $$ AGUIRRE