000 AXPZ20 KNHC 250351 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Wed Oct 25 2023 Tropical Weather Discussion for the eastern Pacific Ocean from 03.4S to 30N, east of 120W including the Gulf of California, and from the Equator to 30N, between 120W and 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0315 UTC. ...SPECIAL FEATURES... Otis has rapidly intensified to a category hurricane centered near 16.1N 99.7W, or about 50 nm south-southeast of Acapulco, Mexico at 25/0300 UTC. It is moving north-northwest at 8 kt. Estimated minimum central pressure is 927 mb. Maximum sustained wind speed has quickly increased to 140 kt with gusts to 170 kt. Satellite imagery shows that Hurricane Otis continues to rapidly intensify as noted in its significantly improved and very symmetrical overall cloud pattern, and in the very cold cloud tops of deep convection surrounding the eye. This convection consists of the numerous strong type within 90 nm in the E semicircle and within 120 nm in the W semicircle. Otis is expected to maintain its current motion for the next day or so, with landfall forecast overnight or early on Wed in southern Mexico. Otis is forecast to remain a category 5 hurricane through landfall, and rapid weakening is then forecast due to the higher terrain of Mexico. Otis will likely dissipate over southern Mexico on Wed night. Hurricane conditions are expected within portions of the hurricane warning area by late tonight and early Wed, with extremely destructive winds near the core. Tropical storm conditions are expected to first reach the coast within the warning areas soon, and then spread northwestward within the warning areas through Wed. Winds affecting the upper floors of high-rise buildings will be significantly stronger than those near ground level. Otis is expected to produce rainfall totals of 8 to 16 inches with maximum amounts of 20 inches through Thursday across Guerrero and the western coastal sections of Oaxaca. This rainfall will produce flash and urban flooding, along with mudslides in areas of higher terrain. Swells generated by Otis will affect portions of the southern coast of Mexico during the next couple of days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office, and please refer to the the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Otis NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from low pressure in northwest Colombia to across central Costa Rica and to 12N92W. It resumes at 10N103W to 08N115W to low pressure near 07N122W 1008 mb to low pressure near 08N135W and to 07N140W. Numerous moderate to strong convection is seen from 05N to 10N between 82W-91W. Scattered moderate convection is within 90 nm southeast of the trough between 103W-105W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on category 5 Hurricane Otis. The area of winds over 20 kt and/or seas over 8 ft associated with Otis currently covers the waters from 13N to 17N between 98W and 101.5W. The pressure gradient between the subtropical ridge to the west of the Baja California Peninsula and relatively broad lower pressure in northwest Mexico is supporting moderate to fresh northwest to north-northwest winds to the west of Baja California. Seas are 6-10 ft with these winds due to long-period northwest swell. Over the Gulf of California, moderate southwest to west winds are present along with seas of 2-4 ft. The remainder of the southwestern Mexican offshore waters outside of Otis are under generally gentle northwest winds and seas 5-6 ft in mixed swell. For the forecast, Hurricane Otis will move inland to near 17.3N 100.1W Wed morning, weaken to a tropical storm near 18.0N 100.5W Wed evening and dissipate Thu morning. Elsewhere, fresh northwest winds across the Baja California offshore waters will diminish to moderate this afternoon. Seas of 8 to 9 ft in long period northwest swell offshore central and northern Baja California will subside Wed. Looking ahead, fresh north winds along with renewed long period northwest swell may develop over the weekend to the west of Baja California. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Generally gentle winds persist north of the monsoon trough. South of the monsoon trough, mainly moderate south to southwest winds prevail. Seas are 6-8 ft between Ecuador and the Galapagos Islands in mixed southwest and northwest swell. Seas are 5-8 ft elsewhere. For the forecast, Moderate southerly winds will continue across the South America and Galapagos Islands offshore waters through Wed. Westerly wind speeds are likely to increase to fresh to strong north of the Equator by early Thu into Fri as broad low pressure forms over the far eastern Pacific waters. Mixed swell will maintain seas in the 6 to 8 ft range across most of the waters through the rest of the week, except 8 to 10 ft near the aforementioned fresh westerly winds and broad low pressure. ...REMAINDER OF THE AREA... A north-south oriented surface ridge extends across the waters between 130W-140W. The gradient resulting from this synoptic set-up is favorable in supporting mainly moderate anticyclonic winds between 130W-140W, and moderate to locally fresh north winds east of 130W and north of 25N. Moderate or weaker winds prevail elsewhere north of the monsoon trough. Moderate south to southwest winds are south of the monsoon trough. Moderate northwest swell continues to propagate across most of the waters between 92W-120W. Seas are 8-9 ft due to long-period northwest swell west of the Galapagos Islands to 115W, mainly south of about 09N. For the forecast long-period northwest swell over the far NE part of the area will continue to spread seas of 8-9 ft north of 26N and east of 130W through Wed afternoon. $$ Aguirre