000 AXPZ20 KNHC 222154 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Jun 22 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...TROPICAL WAVES... A tropical wave extends from 05N to Honduras along 89W-90W, moving west at 15 kt. Scattered moderate convection is noted from 10N to 12N between 91W and 94W. Global models suggest that an area of low pressure associated with this wave is likely to form in a few days, south of the Gulf of Tehuantepec and 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 by the weekend. Interests in southern Mexico should monitor the progress of this system. In addition to strong winds and large seas offshore, 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. A tropical wave extends from 05N to 16N along 105W-106W, moving west 10 to 15 kt. Scattered moderate convection is noted from 11N to 14N between 104W and 106W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N85W to 12N127W. ITCZ extends from 10N129W to beyond 07N140W. In addition to the convection mentioned in the tropical wave section, scattered moderate to isolated strong convection is evident from 07N to 09N between 92W and 94W. Scattered moderate convection is also evident within 90 nm north and 120 nm south of the ITCZ. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A few showers and thunderstorms are evident this afternoon about 90 nm off Punta Eugenia, and over the northern Gulf of California from 29N to 30N. This activity is related to instability and lift ahead of an upper trough west of the area near 120W. Meanwhile, a weak pressure gradient persists across the Baja California peninsula offshore waters supporting gentle to locally moderate NW winds. A scatterometer pass from around 18 UTC indicated light to gentle NW breezes off Baja California and off southern Mexico. Seas are 5 to 7 ft in the open waters off Mexico with a component of SW swell. Gentle to moderate southerly flow and slight seas persist over the Gulf of California. For the forecast, the gentle to moderate NW winds will prevail across Baja California offshore waters through Thu. Winds will 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 tropical wave section above, low pressure is expected to form south of the Gulf of Tehuantepec and 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. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to 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 continue in the 5-8 ft range in SW swell. 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 Wed. REMAINDER OF THE AREA... A high pressure ridge extends across the waters north of 20N and west of 125W and is centered on a 1028 mb high near 37N144W. 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 120W. A surface trough is analyzed along 128W, separating the monsoon trough and the ITCZ. Recent scatterometer data showed NE winds 10-15 kt near the trough. A concurrent altimeter satellite pass just west of the low indicated seas to 7 ft. This is indicative of mainly moderate SW winds prevailing south of the monsoon trough with seas ranging between 5 to 7 ft in southerly swell. 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. $$ Christensen