000 AXPZ20 KNHC 150948 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Nov 15 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 0900 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...High pressure persisting across NE Mexico and the western Gulf of Mexico, behind a slow moving cold front across the central Gulf of Mexico, will continue to support gale-force gap winds funneling into the Gulf of Tehunatepec through Wed night. Peak seas downwind of Tehuantepec are expected to fluctuate between 11 and 14 ft through Thu morning. NW seas generated across Tehuantepec will spread into the outer offshore waters of Guatemala, where seas will remain 7 to 10 ft through late Wed night. Strong gap winds, and associated seas, will gradually diminish Thu into the weekend. Gale Warning NW waters...a large and complex area of low pressure dominates the NE Pacific between the W coast of the U.S. and 145W. A cold front associated with this low is in the far NW waters extending from 31N127W to 20N140W. Gale-force NW winds across the far NW waters W of 136W earlier tonight have diminished below gale-force, as measured by recent scatterometer day. However strong gales continue across that area N of 32N. To the west of the cold front, strong NW to N winds continue, mainly north of 25N and west of 134W. Peak seas with these winds are 17 to 23 ft. The large low pressure system will drift eastward through Thu, then move slowly eastward into the W coast of the U.S. Fri through the weekend. The associated front across the area will move slowly E-SE tonight into Wed, then weaken and stall Wed night through Thu, just W of 122W, with winds and seas behind the front gradually diminishing. However, associated seas of 12 ft and higher will continue to spread SE across the NW waters north of 15N and west of 125W tonight through early Thu. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N74.5W to 08.5N106W to low pressure near 14N123W 1008 mb to 08N129W to beyond 09.5N140W. Scattered moderate to strong convection is noted from 03N to 08.5N E of 86W, and within 120 nm of the coastline between 86W and 90W. Scattered moderate convection is noted from 06N to 09N between 92W and 109W. Scattered moderate to strong convection is also noted from 07N to 16N between 113W and 121W, and from 06.5N to 11N between 122W and 140W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features Section above for details on a Gale Warning in association with gap winds in the Gulf of Tehuantepec. Overnight scatterometer data confirmed gale-force northerly winds across Tehuantepec tonight, extending southwest to near 14N, where seas are assumed to be 10-14 ft. Weak high pressure just offshore of Baja Norte extends a ridge S-SE across the offshore waters of Baja California to 18N. This is producing light to gentle N to NE across these waters, and across all but the entrance to the Gulf of California, where moderate NW winds prevail. Moderate easterly winds are noted near and around Clarion Island extending westward. Seas of 6 to 8 ft in NW swell prevail across the Baja offshore waters. Seas are 1 to 3 ft inside the Gulf of California, except 4 to 5 ft across the entrance. Elsewhere W of Puerto Angel, seas are 5-7 ft in mixed swell. Widely scattered thunderstorms aloft are moving northeastward into the offshore waters N of 25N, producing mainly moderate rain. For the forecast, new NW swell will propagate into the Baja California waters Wed through Thu night, raising seas to 6 to 9 ft. A cold front across the open NW waters along 127W tonight will move slowly E-SE and reach near 122W by Thu before dissipating. High pressure will then build eastward across the area Fri, and strengthen Sat through Sun to bring a return to moderate to fresh northerly winds N of 17N. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds prevail N of 09N, along with seas of 5-7 ft, except well offshore Guatemala where seas have built to 8 ft and higher in NW swell due to ongoing Gulf of Tehuantepec gale- force gap winds. Elsewhere, gentle to moderate SW to W winds prevail south of the monsoon trough, along about 09N, where seas of 5-7 ft in S-SW swell prevail. For the forecast, light to gentle winds will prevail N of 09N with mainly moderate SW to W winds to the S of 09N through early Fri, then briefly increase to moderate to fresh Fri. Meanwhile, southerly swell will continue across the area waters through the weekend producing seas of 5 to 7 ft. Seas are expected to remain 7 to 10 ft in NW swell across the outer offshore waters of Guatemala into Thu due to the extended period of Gulf of Tehuantepec gale-force gap winds. Winds and seas are expected to diminish modestly Sat through early next week as broad low pressure across the SW Caribbean lifts NE and away from the region. ...REMAINDER OF THE AREA... See Special Features section above for information on a gale warning for the far NW waters in association with a strong cold front. A cold front continues to move slowly across the NW waters extending from 30N127W to 20N140W. A narrow band of fresh S to SW winds is found ahead of the front to the N of 26N, where seas are 11 to 12 ft in NW to N swell. Behind the front, NW to W winds gradually increase to strong between the front and 134W, where seas have build to 12 to 18 ft. The gale-force N to NW winds have diminished to around 30 kt across the far NW waters W of 134W, where seas remain 18 to 23 ft. Elsewhere, a surface trough extends from 25N122W to just north of broad low pressure of 1008 mb near 14N123W. Moderate trade winds are noted NE through NW of the low and E of the trough to 115W, where seas are 8 to 9 ft. A weakening high pressure ridge dominates the remainder of the waters between 10N and the cold front, and is supporting moderate or less winds, where seas are 7 to 8 ft. South of 10N, moderate SE winds prevail with southerly swell supporting 6 to 8 ft seas in SE swell. For the forecast, the front will continue to move E-SE through Wed night, then stall and weaken in the vicinity of 122W Thu. Very large seas in excess of 12 ft will gradually spread SE and reach as far E as 125W by Wed night before seas gradually subside through Thu night. Elsewhere, seas of 8-9 ft across the W-central waters will slowly subside, ahead of the expected large NW swell entering the NW waters. Looking ahead, trade winds will start to increase this weekend as high pressure builds back across the region. $$ Stripling