000 AXPZ20 KNHC 230954 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0830 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough begins over Colombia near 09N74W, extends across Panama and Costa Rica then veers WNW to 12N97W to 07.5N115W. The ITCZ extends from 07N119W to beyond 06N140W. Widely scattered moderate isolated strong convection noted from 04N to 13N E of 90W. Widely scattered moderate isolated strong convection is noted within 120 nm N and 210 nm S of trough between 90W and 108W. Scattered moderate to strong convection is noted within 75 nm N and 150 nm S of ITCZ between 123W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak high pressure remains centered well offshore of northern California and extends a weak ridge SE into the area to near 26N120W. This is maintaining a relatively weak pressure gradient across the offshore waters from Baja California to Acapulco tonight, 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 4-6 ft in mixed NW and SW swell and will subside to 4-5 ft by Wed. The pressure gradient will tighten somewhat N of 20N Wed through Fri as the ridge builds modestly into the region, with winds and seas increasing slightly. Gulf of California: Mainly light and variable winds are expected through Thursday, with seas of 1-3 ft, except 4-5 ft in SW swell across the far southern waters. Model guidance suggests fresh to locally strong WSW winds N of 29N Thursday to Saturday as low pressure prevails N of the region. These winds shooting through the gaps in the higher terrain of Baja will increase seas significantly, reaching 6-7 ft each night during the nocturnal wind max. South 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, and the low has drifted W to near 100W and nearly dissipated. Gentle to moderate SE winds occurring between Tehuantepec and offshore of Acapulco will gradually weaken and veer S to SW through Wed. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate SE to E winds prevail between the Papagayo region and Tehuantepec tonight, to the east of the dissipating low along 100W, where seas are 5-7 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 through Tue. Moderate southwesterly winds are expected S of 09N through Thursday night, with seas subsiding slightly tonight through Wed before a new pulse of SW swell arrives Thu through late Fri. REMAINDER OF THE AREA... A weak ridge extends from a 1027 mb high near 41N137W SE to near 26N120W will reposition itself from 32N142W to 11N120W by mid week as a weak frontal trough sweeps southeastward across the waters north of 30N Tuesday and Wednesday accompanied by long period NW swell. This will build seas to 6-8 ft along 32N between 120W and 135W. Elsewhere north of the convergence zone the weak ridge will maintain moderate trade winds S of 18N, with seas of 5-7 ft expected. $$ Stripling