000 AXPZ20 KNHC 210854 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Sep 21 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 0940 UTC. ...TROPICAL WAVES... The axis of a tropical wave is along 104W and from 05N to 18N, moving west at 10 to 15 kt. Scattered moderate convection is noted from 05N to 12N between 100W and 110W. The axis of a tropical wave is along 114W from 05N to 20N, moving west at 10 to 15 kt. Scattered moderate convection is seen from 08N to 20N between 110W and 116W. The axis of a tropical wave is along 126W from 02N to 17N, moving west at around 10 kt. Convection remains limited near the wave axis. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 14N90W to a 1010 mb low pressure near 12N118W to 09N126W. The ITCZ continues from 08N134W to 07N140W. Aside from the convection associated with the tropical waves, scattered moderate convection is from 06N to 10N between 90W and 100W. Scattered moderate isolated strong convection is associated with the 1010 mb low from 10N to 16N between 115W and 122W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak pressure gradient across the region is supporting light to gentle variable winds over the Baja California and SW Mexico offshore waters. Earlier altimeter data showed seas of 3 to 5 ft over these areas where SW and NW swell are converging. Recent scatterometer data shows gentle to locally moderate SE winds along the Gulf of California where seas are up to 3 ft. For the forecast, high pressure will build along Mexico this evening and will support both a gap wind event in the Gulf of Tehuantepec and moderate to locally fresh NW winds along the SW coast of Mexico. Fresh to strong winds are expected to begin in Tehuantepec tonight, increasing to strong to near gale force on Wed and potentially gale force Wed night. Seas will build to 10 ft with this gap event, which is expected to end by Sat. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate southerly winds will prevail across the offshore waters of Costa Rica, Panama, Colombia and Ecuador during the forecast period, with seas of 4-6 ft in SW swell. Mainly light and variable winds are forecast across the offshore waters from Guatemala to northern Costa Rica, with seas of 3-5 ft also in SW swell. In the Papagayo region expect moderate NE-E winds through Tue. REMAINDER OF THE AREA... Seas to 10 ft in NW swell will propagate across the northern forecast waters, mainly between 120W-130W, through late Tue or Tue evening. The northern forecast waters are under the influence of a ridge anchored by a 1026 mb high pressure located near 40N133W. The pressure gradient between the ridge and lower pressures near the monsoon trough/ITCZ supports moderate to locally fresh trades between 10N-20N W of 115W, with seas of 5-7 ft based on altimeter data. Moderate to locally fresh southerly winds are also noted per scatterometer data S of the monsoon trough between 103W- 120W. A broad area of low pressure located about 900 miles southwest of the southern tip of the Baja California peninsula is producing some disorganized shower activity. Environmental conditions are forecast to be somewhat conducive for development during the next few days, and a tropical depression could form during the latter part of this week while the system moves generally NW. By late Friday, the system is forecast to move over cooler waters, which will likely inhibit further development. Please, refer to the latest Tropical Weather Outlook, at www.hurricanes.gov for more details. $$ Ramos