000 AXPZ20 KNHC 252157 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Mon Sep 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 1800 UTC surface analysis and satellite imagery through 2040 UTC. ...TROPICAL WAVES... A tropical wave is analyzed along 118W from 04N to 17N, moving W at 10 to 15 kt. Scattered moderate to strong convection is from 04.5N to 13N between 113W and 124W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10.5N74.5W to 08.5N91W to 10.5N104W to 09.5N116W. The ITCZ extends from 11N129W to 09.5N140W. Scattered moderate to strong convection is noted from 03.5N to 08N E of 84W, from 04.5N to 10N between 86W and 111W, and from 09N to 12N between 126W and 130W. Scattered moderate isolated strong convection is noted about the tropical wave from 04.5N to 13N between 113W and 124W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A modest surface ridge continues to dominate the offshore forecast waters of Baja California, centered on a 1021 mb high near 30N124W. This pressure pattern is supporting mainly fresh NW-N winds from near Cabo San Lazaro northward. Seas are 5-7 ft in NW swell offshore Baja California. Inside the Gulf of California, N-NW winds have increased to fresh across central portions between 26N and 28N, where seas have built to 4 ft. Winds are moderate or weaker elsewhere, with seas of 4-5 ft, except 1-2 ft in the northern Gulf of California. Scattered moderate to strong convection persisting across the coastal waters of southwestern Mexico continues from 13N to 16N between 98W and 102W. For the forecast, the surface ridge across the offshore waters will persist through Wed before high pressure reorganizes well NW of the region. Moderate to fresh NW-N winds offshore Baja California from near Cabo San Lazaro northward will increase to fresh to strong this evening and continue through early Wed. Winds will then gradually diminish Wed through Fri as the ridge shifts NW. Moderate N winds will pulse to strong across the Gulf of Tehuantepec each of the next few nights. Seas will build 8 to 12 ft in new NW swell offshore Baja California Tue through Thu before slowly diminishing Fri through Sat. Looking ahead, low pressure is expected to develop across the northern Gulf of California by Thu, and induce strong SW winds across a large portion of the northern Gulf Fri night. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Winds are generally gentle to the north of 07N, where seas are 4-5 ft. Moderate S to SW monsoonal winds prevail elsewhere to the south of 07N, from offshore Ecuador to the Galapagos Islands. Seas there are 5 to 6 ft. Scattered thunderstorms have flared up this afternoon to the north of 03.5N and east of 84W, as a tropical wave is moving across Panama and the local waters. For the forecast, Gentle to moderate winds will continue north of 07N with seas 5 ft or less through Thu night. Moderate to fresh SW monsoonal winds will prevail to the S of 07N through mid week. Slight to moderate seas will continue, highest offshore Ecuador to the Galapagos Islands, before seas build slightly region-wide in S-SW swell beginning Wed. Active weather will continue across the waters of western Panama and Costa Rica through Wed associated with a tropical wave passage. ...REMAINDER OF THE AREA... The remnants of T.C. Fourteen-E are centered near 15.5N129.5W as a 1010 mb swirl of mostly low level clouds. Fresh to strong winds are noted across the northern semicircle with the low, with seas to 10 ft. Scattered moderate to strong convection has intensified in recent hours near the ITCZ to the south, from 09N to 12N between 126W and 130W. A surface trough continues along 131W-132W from 24N to 27N. Scattered shallow convection is east of the trough to 128W. Associated winds are moderate with remnant 5 ft seas in mixed swell across the N side. Elsewhere N of 20N and W of 120W, anticyclonic winds are moderate or weaker, and seas are 4-6 ft. S of 20N and to the west of the remnants of Fourteen, the modest pressure gradient between a weak high pressure ridge along 27N and lower pressure near the ITCZ is yielding moderate ENE trade winds and seas of 5 to 7 ft in mixed N and SE swell. New southeasterly swell has moved across the equator, and is building seas to around 8 ft to 01N and W of 110W, and will propagate northwestward over the next 48 hours. For the forecast, the remnants of T.C. Fourteen-E will weaken to a trough during the next 48 hours while moving west-southwestward. The surface trough near 131W will gradually shift W-SW and dissipate through Tue. A cold front approaching the far NW waters will sink slowly into those NW waters tonight through Wed night and stall. High pressure north of the front will increase the pressure gradient to the west of 125W, and freshen the winds Tue through Thu. This will also coincide with the arrival of large NW to N swell generated across the NE Pacific in recent days. This swell will push into the northern waters this afternoon, building seas to 7-11 ft N of 10N and W of 115W by the middle of the week. Elsewhere, weak high pressure will prevail N of the monsoon trough and E of 120W through Wed and yield moderate or weaker winds. Looking ahead, another pulse of SE swell will enter the area S of the equator by mid week and spread N through Fri. $$ Stripling