000 AXPZ20 KNHC 111019 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Nov 11 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 0910 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec developing gale...High pressure is building southward tonight across northeast Mexico behind a cold front that has begun to stall across the NW Gulf of Mexico. The front is expected to reach the western Bay of Campeche later today and then reach the central Bay of Campeche on Sun. Strong high pressure behind the front will force strong to near gale-force northerly gap winds across the Gulf of Tehuantepec Sat afternoon through Sun then increase to minimal gale-force Sun evening through Tue morning. The front is expected to shift slightly eastward across the Gulf of Mexico Tue through Wed with winds increasing to near 40 kt across Tehuantepec at that time. Seas will build to near 11 ft just downwind of Tehuantepec Sat night then to near 12 ft Sun night through Tue as gales begin. Seas may peak near 14 ft Tue night. As this event evolves Mon night through Tue, NW seas generated across Tehuantepec will move into the outer offshore waters of Guatemala, where seas will build to7 to 10 ft. Gale are expected to end Wed night, with the strong gap winds gradually diminishing through the end of the work week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10.5N74W to near 09.5N97W to low pressure near 08N105W to 09N110W, then resumes from low pressure near 14N114.5W to 10N124W. The ITCZ extends from 10N125W to beyond 07.5N140W. Scattered moderate to strong convection is noted from 03.5N to 08N E of 86W, from 04N to 10.5N between 90W and 104W, from 05N to 16N between 104W and 113W, and from 07N to 09N W of 133W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure centered NW of the area extends a broad ridge SE across the offshore waters of Baja California and SW Mexico. The pressure gradient between the ridge and the monsoon trough extending northward to just SW of the Revillagigedo Islands is producing gentle to moderate northerly winds across the Baja offshore waters N of 18N, and moderate to locally fresh N-NW winds throughout the Gulf of California. Seas of 5 to 7 ft prevail in mainly NW swell across the Baja offshore waters, and 3-5 ft inside the Gulf of California. Light to gentle winds prevail elsewhere S of 18N to Puerto Angel, where seas are 4-6 ft in mixed S-SW and NW swell. Overnight scatterometer data showed fresh northerly gap winds beginning across the Gulf of Tehuantepec and extending southward to 15N. For the forecast, winds will increase to strong in the Gulf of Tehuantepec overnight, then strong to near gale force early Sat through Sun morning, as a cold front moves slowly across the western Gulf of Mexico. Seas will gradually build 8-10 ft there. Winds are then forecast to pulse to gale force each evening and night, starting Sun evening and continuing through Tue. See the Special Features section above for more details on this Tehuantepec gale event. Meanwhile, gentle to moderate northerly winds will continue across the Baja offshore waters through Sat night before diminishing Sun into early next week. Moderate to fresh winds are forecast in the Gulf of California, gradually diminishing from the entrance northward through early Sun. A series of NW swell events are forecast to propagate across the Baja California waters beginning Sat, then again Mon, and then a larger event beginning Wed. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate NE-E gap winds prevail across the Gulf of Papagayo region with seas to 5 ft. Light to gentle winds are noted elsewhere N of 09N, along with seas of 3-5 ft. Gentle to moderate S to SW winds prevail to the south of the monsoon trough, along 09N, where seas of 5-7 ft in S-SW swell prevail. For the forecast, moderate NE to E gap winds across the Papagayo region will pulse to fresh Sat, then fresh to strong Sat night and to fresh Sun night. Light to gentle winds will prevail elsewhere N of 09N with mainly moderate southerly winds S of 09N through early next week. Meanwhile, southerly swell will build across the waters N of 08N, with seas of 4-7 ft prevailing basin- wide this weekend into Mon, before yet another strong pulse of S-SW swell arrives Mon to increase seas slightly into mid-week. Looking ahead, seas will build to around 8 ft well offshore Guatemala Tue night through Wed due to a nearby Gulf of Tehuantepec gale-force gap wind event. ...REMAINDER OF THE AREA... High pressure centered just NW of the area and an accompanying ridge dominates the waters N of the monsoon trough/ITCZ. A fairly tight pressure gradient is across these waters W of 120W, with fresh to strong trades from 10N to 25N and W of about 120W. Seas of 8-11 ft in fresh NE wind waves and NW swell are across those waters, with recent altimeter data measuring a peak of 12 ft near 10N 137W. A 1008 mb low center is near 14N114.5W and moving westward. The pressure gradient between the low and the ridge to the NW is producing fresh NE winds within 360 nm across the NW quadrant of the low, as captured by overnight scatterometer data. Seas are 8-9 ft in this quadrant. Moderate to fresh trades are elsewhere N of the monsoon trough/ITCZ and W of 120W. Southerly swell supports seas of 7-8 ft from S of the monsoon trough/ITCZ across the Equator. For the forecast, high pressure will continue to support fresh to strong winds in the trade wind belt overnight, diminishing to fresh Sat morning, then slowly diminishing further Sun and Sun night. Meanwhile, seas of 8-11 ft will persist across the W-central waters into early Sun, gradually decaying through Sun night. The southerly swell around 8 ft will linger from 06N southward across the Equator into early next week. Looking ahead, deepening low pressure is expected to develop across the NE Pacific by Mon and move SSE, and remain just NW of the area waters. Ahead of the low, a strong cold front will sink into the NW waters MOn afternoon to produce fresh to near gale force NW winds Mon night through Tue night. Associated seas in excess of 12 ft will accompany the increasing winds, with seas around 20 ft expected across the far NW waters early Tue shifting slowly eastward through Wed. $$ Stripling