818 AXPZ20 KNHC 121528 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1443 UTC Wed Sep 12 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 1500 UTC. ...TROPICAL WAVES... A tropical wave is along 111W/112W from 04N to 16N moving westward at around 5 to 10 kt. Scattered moderate and isolated strong convection is propagating out ahead of the wave from 10N to 14N between 113W and 118W. This tropical wave is likely to become diffuse and difficult to track in the next 24-48 hours. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from low pressure over northern Colombia near 09N75W to 08N80W to 11N90W to 11.5N110W, then resumes from 14N130W to beyond 12N140W. Scattered moderate and isolated strong convection is from 04N to 10N between 78W and 95W, from 10N to 13N between 121W and 130W, and also from 10N to 15N between 130W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gentle to moderate winds will prevail in the Gulf of California through the remainder of the week and into the upcoming weekend. Seas will be mainly 3 ft or less, except 3 to 5 ft near the entrance. A gentle to moderate NW flow will prevail across the offshore waters W of Baja California, with seas generally in the 5 to 7 ft range. Winds and seas will slightly increase N of Punta Eugenia Fri night through Sat night. Marine guidance suggests winds in the 15 to 20 kt range, with seas of 6 to 8 ft. Additional pulses of long period southerly swell are forecast to reach the entrance of the Gulf of California, and the waters W of Baja California this morning. A surface trough is located midway between Cabo Corrientes and Los Cabos. Scattered moderate to isolated strong convection is noted from 16N to 22N E of the trough axis to 110W. Any significant organization of this system is likely to be slow to occur while the system drifts southwestward over the next couple of days before upper-level winds become unfavorable for development. The latest Tropical Weather Outlook gives this system a low change of tropical cyclone development during the next 48 hours, and also through 5 days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will meander between 08N and 10N during the next several days. Winds on both sides of the trough axis will be gentle to moderate, increasing to moderate to fresh S of the axis by the end of the week into the weekend as broad low pressure along the axis deepens slightly. Another pulse of cross-equatorial southerly swell is propagating northward. This swell event is currently reaching the coasts of Mexico and Central America. Seas are already between 7 and 9 ft across the waters between Ecuador and the Galapagos Islands, and will build to such near the Azuero Peninsula later today into tonight. Seas are expected to further build to 9 or 10 ft across the offshore forecast waters of Panama and Costa Rica toward the end of the week into the upcoming weekend. REMAINDER OF THE AREA... The last forecast/advisory of tropical cyclone Paul was issued by the National Hurricane Center at 12/0900 UTC, and for the first time since 14 August, the northeast Pacific has no tropical cyclones. Paul has been void of any deep convection for several hours and is no longer a tropical cyclone. The most recent scatterometer pass showed 20 to 30 kt winds on the NW side of the remnant circulation, where seas of 8 to 10 ft are also still likely. The remnant low of Paul will move westward with the associated winds and seas gradually diminishing through 48 hours. Otherwise, a ridge dominates the NW portion of the forecast waters. The pressure gradient between the remnant low of Paul and the ridge is producing an area of moderate to locally fresh NE mainly N of 22N W of 125W based on recent scatterometer and altimeter data. The pressure gradient is forecast to slacken as Paul continues to spin down with mainly gentle to moderate trades and 4 to 7 ft seas by the start of the upcoming weekend. Looking ahead...An area of low pressure is expected to develop well south of the southwestern coast of Mexico in a few days. Some gradual development is possible after that time while the system moves generally westward to west-northwestward. $$ GR