000 AXPZ20 KNHC 271550 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1412 UTC Fri Apr 27 2018 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 1200 UTC surface analysis and satellite imagery through 1445 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 07N77W to 05N83W to 06N91W to 07N101W. The intertropical convergence zone continues from 07N101W to 08N106W to 08N126W to beyond 06N140W. Scattered moderate and isolated strong convection is present within 90 nm of the monsoon trough axis between 77W and 100W and from 05N to 08N between 103W and 111W and from 07N to 10N between 121W and 130W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... In the upper levels, the northern jet digs into the base of an upper-level trough to the W of California, coming into phase with the southern jet moving across Baja California Norte. This split pattern is is enhancing surface troughing and lower pressure over the Gulf of California and northwest Mexico, tightening the gradient between the trough and high pressure ridging southeastward to near the Revillagigedo Islands. Fresh NW winds along the coast of Baja California N of 25N will increase to fresh to strong by this evening as ridging continues to build southeastward into the area and a trough deepens over the Colorado River valley through the northern Gulf of California. Altimeter passes from very early this morning showed seas to 8 ft between the Revillagigedo Islands and Cabo San Lazaro, likely due to a dominant NW swell component. NW winds off Baja California Norte will continue to increase through Sat night as the upper trough swings E across the region and causes the surface low pressure to deepen. Seas will build north of Cabo San Lazaro due to the increased winds. Seas will peak between 8 and 10 ft on Sat, but subside farther south. Winds and seas will then diminish through early next week as the upper-level trough continues eastward and high pressure builds into the region. Pulses of strong westerly gap winds are possible over the northern Gulf of California as the trough shifts eastward late Sun into Tue. Farther south, pulses fresh to strong northerly winds are possible over the Gulf of Tehuantepec this weekend, particularly during Sat morning as nocturnal drainage flow augments high pressure building over the western Gulf of Mexico. Elsewhere, mainly light to gentle winds are expected through Mon accompanied by 4 to 6 ft seas. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh northeast nocturnal winds are expected in and downstream of the Gulf of Papagayo beginning Sun night. Gentle to moderate offshore flow will prevail elsewhere N of 09N, and light to gentle SW winds are expected S of 09N along with seas of 4 to 6 ft. REMAINDER OF THE AREA... A ridge is building SE from 1025 mb high pressure centered over the north central Pacific near 34N143W to the Revillagigedo Islands. Moderate to fresh northeast trade winds and 7 to 9 ft seas are observed across the tropical waters W of 115W between 08N and 20N, or south of the subtropical ridge and north of the ITCZ. These winds will increase to fresh to locally strong as the pressure gradient increases over this region through Sun. This will also result in an increase in the areal coverage of 8 to 9 ft seas. Winds and seas will decrease early next week as the high centered N of the area shifts northward and slowly weakens. $$ CAM