000 AXPZ20 KNHC 230913 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed Jun 23 2021 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 0800 UTC. ...SPECIAL FEATURE... A tropical wave extends from 05N to coastal Mexico along 94W, moving west at 15 kt. Scattered moderate to strong convection is noted from 07N to 15.5N between 88W and 98W. Global models suggest that an area of low pressure associated with this wave is likely to form in the next few days, south of southeastern Mexico. Environmental conditions appear conducive for gradual development of this system, and a tropical depression is likely to form by the end of the week or this weekend. This disturbance is expected to move slowly west-northwestward to northwestward, and could be near the coast of southern Mexico during the weekend. Interests in southern Mexico should monitor the progress of this system. In addition to strong winds and large seas near this system, the main weather impact will be the potential for heavy rainfall along the mountainous coast of Guerrero, Michoacan, and Colima. This is in the same general area that experienced heavy rainfall from Dolores a few days ago. ...TROPICAL WAVES... A tropical wave extends from 05N to 16N along 108W, moving west 10 to 15 kt. Scattered moderate convection is noted from 07N to 15N between 104W and 109W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N74W to 13N102W to 11N122W. ITCZ extends from 11.5N125W to low pres 1013 mb near 12.5N128.5W to beyond 07N140W. In addition to the convection mentioned in the tropical wave section, scattered moderate convection is evident from 01.5N to 09N E of 87W. Scattered moderate isolated strong convection is noted from 07N to 15N between 98W and 109W, within 150 nm of the Mexican coast between 97W and 106W, from 07N to 12N between 109W and 127W, and within 60 nm N and 120 nm S of the ITCZ between 127W and 140W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A few bands of scattered showers and isolated thunderstorms are evident this morning within 120 nm of the coast of Baja Norte from offshore of Punta Eugenia and 27N to southern California, and across the northern Gulf of California N of 28N and into mainland Mexico. This activity is related to instability ahead of an upper trough just west of 120W, and a weakening low level cyclonic circulation near 25N117W. Meanwhile, a weak pressure gradient persists across the Baja California peninsula offshore waters supporting gentle to locally moderate NW winds. Overnight scatterometer data indicated light to gentle NW breezes off Baja California Norte, and gentle winds south of Punta Eugenia. Seas are 4 to 6 ft in the open waters off Baja and 4 to 7 ft offshore of southern Mexico with SW swell. Gentle to moderate southerly flow and slight seas persist over the Gulf of California. The gentle to moderate NW winds will prevail across Baja California offshore waters through early Thu. Winds will gradually increase across the Baja California Norte offshore waters Thu into the weekend as a ridge shifts eastward and builds across the region. Looking ahead, as discussed in the special features section above, low pressure is expected to form south of southeastern Mexico in the next few days and move W-NW or parallel along the Mexican coast through the weekend. A tropical depression is likely to develop from this system. This will bring the potential for winds to gale force with rough seas off the coast of Guerrero, Michoacan, and Colima, and potential for heavy rainfall. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to locally moderate SW to W winds prevail south of the monsoon trough, except where stronger winds are occurring near very active convection associated with a tropical wave. Elsewhere light to gentle variable winds generally prevail north of the monsoon trough. Seas are in the 5-7 ft range in SW swell except 7-8 ft between the Galapagos Islands and Ecuador. Gentle to moderate SW to W winds are expected south of the monsoon trough through Wed, while moderate SE to E winds prevail north of the trough. Long period SW swell across the regional waters will gradually subside through today with another smaller pulse expected for the weekend. REMAINDER OF THE AREA... A high pressure ridge extends across the waters north of 20N and west of 125W and is centered on a 1026 mb high near 36N143W. The pressure gradient between this area of high pressure and lower pressure within the monsoon trough/ITCZ is supporting gentle to moderate winds north of 08N and west of 125W. A 1012 mb surface low is near 12.5N128W, where winds near 20 kt within 180 nm of the NW area 7-8 ft. Wave heights are expected be 6 to 8 ft across the tropical waters near the ITCZ west of 130W later in the week, with 5 to 7 ft elsewhere. $$ Stripling