987 AXPZ20 KNHC 231005 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Oct 23 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURES... Tropical Storm Otis is centered near 11.4N 97.1W, or about 370 nm south-southeast of Acapulco, Mexico at 23/0900 UTC, moving north at 4 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peak seas are about 14 ft. Satellite imagery shows increasing numerous moderate to strong convection within 150 nm of the center in the NW quadrant. Scattered moderate to isolated strong convection is to the northeast of Otis from 12N to 14N between 95W-97W. Otis is expected to maintain a north-northwestward to northward motion is expected during the next few days. On the forecast track, the center of Otis will be approaching the southern coast of Mexico late Tue into Wed. Some gradual strengthening is forecast during the next couple of days. Otis is expected to produce rainfall totals of 5-10 inches with maximum amounts of 15 inches across Guerrero and the western coastal sections of Oaxaca. This rainfall is likely to produce flash and urban flooding, along with mudslides in areas of higher terrain. Swells generated by Otis will begin to affect portions of the southern coast of Mexico by late Tuesday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office, and read 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. Recently downgraded Tropical Storm Norma is centered near 24.5N 108.4W, or about 50 nm west-southwest of Culiacan, Mexico at 23/0900 UTC, moving east at 6 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Peak seas are around 20 ft, but gradually subsiding. Satellite imagery depicts Norma as a sheared system, with its clearly exposed center visible over the southern Gulf of California. It has been lacking convection since yesterday. On the current forecast track, the center of Norma is forecast to move inland along the coast of the Mexican state of Sinaloa later this morning. Little change in strength is expected before Norma reaches the coast of Mexico. Weakening and dissipation is anticipated once Norma moves inland. Rainfall from Norma will diminish across northern portions of Sinaloa, northern Durango and southern Chihuahua later today. Additional isolated totals of 1-2 inches are possible, along with isolated flash flooding and mudslides in areas of higher terrain. Swells generated by Norma will continue to affect the coast of southwestern and west- central Mexico and Baja California Sur for the next day or so. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office, and read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml and the latest Norma NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from western Colombia to low pressure of 1006 mb just southeastern Nicaragua, and continues southwestward from there to 09N92W. It resumes at 10N104W to 10N120W to 0N131W. The ITCZ extends from 10N131W to 10N140W. Scattered moderate to isolated strong convection is from 05N to 10N between 82W-87W, and within 180 nm south of the trough between 104W-110W. Scattered moderate convection is seen from 06N to 09N between 110W-112W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the SPECIAL FEATURES section above for more details on Tropical Storm Otis and on recently downgraded Tropical Depression Norma. The pressure gradient between the subtropical ridge to the west of the Baja California Peninsula and Norma is supporting fresh to strong northwest to north winds along the Baja Peninsula offshore waters. Seas are 8-10 ft with these winds. Similar seas are near entrance of the Gulf of California. Light to gentle winds are in the Gulf of California north of 27N. Seas are 3-5 ft there. The remainder of the southwestern Mexican offshore waters have light to gentle variable winds prevailing and seas to 7 ft in mixed swell. For the forecast, recently downgraded Tropical Depression Norma is near 24.5N 108.4W, or about 50 nm west-southwest of Culiacan, Mexico at 23/0900 UTC, moving east at 6 kt. Maximum sustained winds are 30 kt with gusts to 40 kt, and the minimum central pressure is 998 mb. Norma will move inland to 24.7N 107.3W this afternoon, and dissipate Tue morning. Additionally, Tropical Storm Otis is near 11.4N 97.1W, or about 370 nm south-southeast of Acapulco, Mexico at 2 AM PDT. It is moving north at 4 kt. Maximum sustained winds are 40 kt with gusts to 50 kt, and the minimum central pressure is 1002 mb. Otis will move to near 12.1N 97.3W this afternoon, to near 13.0N 97.5W late tonight, to near 14.0N 97.9W Tue afternoon with maximum sustained winds 50 kt gusts 60 kt and maintain intensity as it moves to near 15.0N 98.4W late Tue night, to near 15.6N 98.8W Wed afternoon and to near 16.4N 99.4W late Wed night. Otis will weaken to a tropical depression while moving inland Mexico near 17.9N 100.7W late Thu night. Elsewhere, strong winds will continue this morning across the Baja California offshore waters N of Cabo San Lazaro. Northwest swell across the Baja California offshores along with swell generated by Norma will continue to subside by late this afternoon at the entrance of the Gulf of California. A new set of long period northwest swell will enter the offshores of Baja California Norte north of Punta Eugenia tonight and subside Wed morning. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the SPECIAL FEATURES section above for more details on Tropical Storm Otis. Outside of Otis, overnight ASCAT data showed generally light to gentle winds persist north of the monsoon trough. South of the monsoon trough, Gentle to moderate gentle south to southwest winds are south of the monsoon trough. Seas are 8-10 ft in the far southwest section of the Guatemala offshore waters due to Otis. Seas are 6-8 ft west of the Galapagos Islands due to mostly northwest swell. Otherwise, seas range 5-7 ft due to mixed southwest and northwest swell. For the forecast, Otis will move to near 12.1N 97.3W this afternoon, to near 13.0N 97.5W late tonight, to near 14.0N 97.9W Tue afternoon with maximum sustained winds 50 kt gusts 60 kt and maintain intensity as it moves to near 15.0N 98.4W late Tue night, to near 15.6N 98.8W Wed afternoon and to near 16.4N 99.4W late Wed night. Otis will weaken to a tropical depression while moving inland Mexico near 17.9N 100.7W late Thu night. Elsewhere, winds will increase to locally fresh across the South America and Galapagos Islands offshore waters briefly on Mon. Otherwise, gentle to moderate winds will prevail across the area through most of the week. Mixed swell will create seas to 8 ft across most of the waters through most of the week. ...REMAINDER OF THE AREA... Please see the SPECIAL FEATURES section above for more details on Tropical Storm Otis and on recently downgraded Tropical Depression Norma. Surface ridging extends across the northern forecast waters, N of 16N and W of 120W. This is supporting gentle to moderate N to NE winds N of the monsoon trough and west of 120W. Gentle to moderate south to southwest winds are south of the monsoon trough as seen in overnight ASCAT data. Large northwest swell continues to propagate across most of the waters between 94W- 115W along with seas of 8-9 ft. For the forecast, Otis will move to near 12.1N 97.3W this afternoon, to near 13.0N 97.5W late tonight, to near 14.0N 97.9W Tue afternoon with maximum sustained winds 50 kt gusts 60 kt and maintain intensity as it moves to near 15.0N 98.4W late Tue night, to near 15.6N 98.8W Wed afternoon and to near 16.4N 99.4W late Wed night. Otis will weaken to a tropical depression while moving inland Mexico near 17.9N 100.7W late Thu night. Elsewhere, a weak pressure pattern will support mainly gentle to moderate winds across the open waters through today. Winds may increase moderate to fresh on Mon as high pressure builds N of the area and tightens the pressure gradient. Meanwhile, a new set of long-period northwest swell is forecast to spread south of 30N and the east of 130W beginning this afternoon, potentially building seas of 8-10 ft ft north of 26N, with the highest seas north of 29N. $$ Aguirre