000 AXPZ20 KNHC 280142 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Tue Sep 28 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 0000 UTC surface analysis and satellite imagery through 0130 UTC. ...TROPICAL WAVES... A tropical wave has its axis along 106W/107W, from 02N to 15N, moving west at 10 to 15 kt. This wave is moving through a very moist environment. Associated convection is described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from northern Colombia near 10N75W to across northern Costa Rica to 10N86W to 1010 mb low pressure near 09N98W to 13N100W to 12N140W. Scattered moderate and isolated strong convection is noted from 03N to 10N between 78W and 88W, from 08N to 14N between 117W and 122W, and from 10N to 16N between 123W and 132W. Scattered moderate convection is noted within 90 nm of the monsoon trough between 91W and 100W, and within 17N104W to 10N101W to 06N108W to 13N114W to 17N104W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate to fresh NW-N winds are noted west of Baja California, the strongest offshore of Baja California Sur. Mainly light to gentle winds prevail elsewhere offshore of Mexico. Seas are in the 5 to 7 ft range in mixed long period swell, except 3 to 5 ft from Cabo Corrientes to the entrance to the Gulf of California, and 3 ft or less in the central and northern Gulf of California. For the forecast, moderate to fresh winds offshore of Baja California and in the northern Gulf of California will diminish somewhat by mid-week. A tropical wave currently well south of southern Mexico may bring increasing winds and seas to the vicinity of the Revillagigedo Islands and southern Baja California by the end of the week into the weekend as low pressure may develop along it and move NW or N. Otherwise, mainly gentle winds will prevail offshore of Mexico through the week and into the weekend. Large NW swell will impact the waters west of Baja California by Tue night, subsiding by the end of the week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate to fresh NE-E winds are noted in the Papagayo region. Light to gentle winds are noted elsewhere north of the monsoon trough. Moderate S-SW winds prevail south of the monsoon trough. Seas are mainly in the 5 to 7 ft range in mixed long period SW and NW swell. For the forecast, moderate to fresh offshore winds will pulse across the Papagayo region through mid-week. Otherwise, light to gentle winds will prevail north of he monsoon trough, with mainly moderate S-SW winds south of the monsoon trough. Cross- equatorial southwest swell will propagate through the regional waters during the next several days. REMAINDER OF THE AREA... A cold front is noted just NW of the discussion area. A weak ridge extends across the northern waters south of the front with light to gentle winds under it. An area of moderate to fresh NE winds are noted west of a surface trough which reaches from 24N130W to 15N138W. Gentle to moderate trades prevail elsewhere north of the convergence zone. Fresh to locally strong SW winds are south of the monsoon trough between 110W and 120W. These winds are helping to support seas of 8 to 10 ft across that area. Mainly moderate southerly flow prevails elsewhere south of the monsoon trough, with seas of 5 to 7 ft elsewhere across the open waters. For the forecast, the cold front will sink south of 30N through mid-week, gradually weakening. Associated NW-N swell will arrive behind it building seas to 8 to 11 ft across much of the waters north of 20N. Winds will freshen north of the convergence zone from the middle through the end of the week as high pressure builds in behind the decaying front. These winds combined with the NW-N swell will support a ribbon of seas around 8 ft from north of the convergence zone to 20N and west of 120W. More tranquil marine conditions are likely during the upcoming weekend. $$ Lewitsky