000 AXPZ20 KNHC 231500 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1521 UTC Tue May 23 2017 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 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N84W to 12.5N95W to 08.5N108W. The intertropical convergence zone axis extends from 08.5N108W to 08N120W to 07N140W. Scattered moderate and isolated strong convection is N of 07N between 78W and 80W, N of 14N between 92W and 96W, N of 16N between 99W and 101W, and from 04N to 09N between 127W and 135W. Isolated moderate to strong convection is within 120 nm S of the axis between 91W and 117W, and within 120 nm N of the axis between 118W and 122W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak high pressure remains centered well offshore of northern California, extending a weak ridge SE into the area through 30N130W to near the Revillagigedo Islands. This is maintaining a relatively weak pressure gradient across the offshore waters from Baja California to Acapulco, with moderate NW winds prevailing across the Baja peninsula waters, and light NW to W winds from Las Tres Marias to Acapulco. Seas are running 4 to 6 ft in mixed NW and SW swell and will subside to 4 to 5 ft by tonight. The pressure gradient will tighten somewhat N of 20N Wednesday through Friday as the ridge builds modestly into the region, with winds and seas increasing slightly. In the Gulf of California, mainly light and variable winds are expected through Thursday, with seas of 2 ft or less, except 3 to 4 ft near the entrance. Low pressure will deepen just N of the area over SW Arizona Wednesday night through the end of the week. A trough will extend from that low across the northern Gulf to Baja California Norte. Fresh to strong southerly winds will develop SE of the trough Wednesday night, and then again on Thursday night as winds become enhanced through the gaps in the higher terrain of Baja. Seas will increase significantly, reaching 6 to 7 ft each night during the nocturnal wind max. S of 16N including the Gulf of Tehuantepec, broad and weak low pressure has persisted across the offshore waters SW of Tehuantepec the past few days, drifting to the W. Gentle to moderate SE to S winds occurring between Tehuantepec and offshore of Acapulco will gradually weaken and veer S to SW through Wednesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh SE to E winds prevail between the Papagayo region and Tehuantepec, with seas of 5 to 7 ft in SW swell. Expect these conditions to continue today before gentle to moderate SW to W monsoonal winds spread N of 09N and into the coastal waters tonight into early Wednesday. Nocturnal offshore winds will pulse to fresh levels near the Gulf of Papagayo Saturday night. Moderate SW winds are expected S of 09N through Thursday night, with seas subsiding slightly through Wednesday before a new pulse of SW swell arrives Thursday through late Friday. Otherwise, little change is anticipated through the upcoming weekend. REMAINDER OF THE AREA... A weak ridge extends from a 1028 mb high near 40N139W SE to near 30N130W. The ridge will reposition itself from 32N142W to 11N120W by Wednesday as a weak front or trough moves SE across the waters N of 30N by early Wednesday, accompanied by long period NW swell. This will build seas to 6 to 8 ft from 30N to 32N between 120W and 135W. Elsewhere N of the convergence zone, the weak ridge will maintain moderate trade winds S of 18N, with seas of 5 to 7 ft expected. Little change is anticipated through the upcoming weekend. $$ LEWITSKY