000 AXPZ20 KNHC 182121 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2121 UTC Sat May 18 2019 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 07N81W to 1008 mb low pressure near 12N95W to 07N120W. The ITCZ continues from 07N120W to 05N135W. Scattered moderate isolated strong convection was noted from 02N to 14N between 81W and 96W. Scattered moderate isolated strong convection was noted within 120 nm in the southeast quadrant of the low pressure. Scattered moderate convection was noted within 90 nm south of the monsoon trough between 100W and 110W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge extends from 1021 mb high pressure centered west of the area near 25N127W to near the Revillagigedo islands, while a trough extends across the Gulf of California. The pressure gradient between these features is resulting in moderate to fresh winds west of the Baja California peninsula. Seas over this area are in the 7-9 ft range in a mix of SW and NW swell. Light to gentle winds and seas in the 4-6 ft range prevail across the remainder of the open waters off Mexico. Light and variable winds with seas of 2 ft or less prevail across the Gulf of California. The high pressure will weaken through the evening ahead of an approaching cold front that will move into the waters off Baja California Norte into the northern Gulf of California Sun into Mon, then dissipate by Tue. A large set of long period southerly swell will continue to move into the Mexican offshore waters through Mon before mixing with northwest swell beginning on Mon night. Looking ahead, another weak cold front may move across Baja California Norte and the northern Gulf of California by mid week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A weak pressure pattern will maintain gentle to moderate onshore winds across most of the region for the next several days. Large cross-equatorial southwest swell off Ecuador will move into the outer offshore waters of Central America late Sun into mid week. Deep atmospheric moisture, within a relatively broad area of low pressure, will remain across just about the entire offshore waters of these areas well into next week along with scattered to numerous showers and thunderstorms, some of which can produce very heavy rain and strong gusty winds. REMAINDER OF THE AREA... 1021 mb high pressure centered near 25N127W will dissipate through this evening ahead of an approaching cold front currently extending from 30N135W to 28N140W. The front will move eastward across the waters north of 20N through early Mon. Seas of 8 to 10 ft in NW swell will follow the front across the area north of 20N as well. High pressure will follow across the waters north of 20N in the wake of the front starting Sun. This will allow relatively weak trade winds deeper into the tropics and west of 130W in increase accordingly. The combination of the northerly swell, a component of southerly swell and local winds will allow seas to build through the trade wind belt west of 120W through mid week. Increased trade wind convergence will also allow an increase in showers and thunderstorms along the ITCZ from early to mid week. $$ Christensen