000 AXPZ20 KNHC 191507 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sun Sep 19 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...TROPICAL WAVES... The axis of a tropical wave is along 95W and N of 04N, moving west at around 10 kt. Scattered moderate and isolated strong convection is noted from 04N to 08N between 88W and 89W, and from 10N to 12N between 91W and 98W. The axis of a tropical wave is along 105W and N of 05N, moving west at around 10 kt. Scattered moderate and isolated strong convection is noted from 04N to 11N between 101W and 108W, and from 11N to 18N between 99W and 108W. The axis of a tropical wave is along 119W from 04N to 17N, moving west at around 10 kt. Scattered moderate and isolated strong convection is noted from 11N to 16N between 114W and 117W. Scattered moderate convection is noted from 08N to 11N between 117W and 122W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 1010 mb low pressure over northern Colombia near 11N75W to across western Panama and Costa Rica to 09N90W to 11N101W to 10N108W to 1010 mb low pressure near 11.5N114W to 10N120W to 12N140W. Scattered moderate and isolated strong convection is noted from 02N to 07N between 77W and 84W, from 08N to 11N between 84W and 87W, from 06N to 10N between 123W and 131W, and from 11N to 13N between 139W and 140W. Scattered moderate convection is noted within 120 nm northeast of a line from 18N132W to 10N127W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough extends from 20N108W southwestward, and scattered moderate to strong convection is noted from near Cabo Corrientes at 19N to 24N between the coast of Mexico at 105W and 109W. Otherwise, broad surface ridging extends across the waters west of Baja California with moderate to fresh winds there. Light to gentle winds are noted elsewhere offshore of Mexico, except locally moderate in the Gulf of Tehuantepec and also offshore of Michoacan and Colima. Seas are mainly in the 4 to 7 ft range in a mixed swell, highest offshore of Baja California Sur, and except 2 to 4 ft in the Gulf of California. For the forecast, surface ridging west of California will promote moderate to fresh NW winds along the west coast of Baja California today. NW swell will build seas west of Baja California Norte Mon night through Tue night in the vicinity of a frontal boundary that will dissipate by midweek. A Gulf of Tehuantepec gap wind event will begin Tue night and may bring near-gale conditions Wed through Thu night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Moderate to fresh offshore winds are in the Papagayo region. Light to gentle winds are noted elsewhere north of 06N, with moderate to locally fresh S-SW winds south of 06N. A SW swell is promoting seas in the 5 to 7 ft range across the equatorial waters, and 4 to 6 ft across the Central American waters. For the forecast, moderate SW swell across the equatorial waters will subside by tonight. Moderate to fresh winds will pulse in the Papagayo region through today. Otherwise, tranquil conditions should prevail through Thu night. REMAINDER OF THE AREA... A cold front is approaching 30N from the northwest. A broad surface ridge prevails south of the cold front across the open waters north of the convergence zone. A 1010 mb low pressure area is along the monsoon trough near 11.5N114W, with a surface trough extending northeast of the low to near 20N108W. Associated convection is described above. Gentle to moderate trades are noted north of the convergence zone, locally fresh south of 21N, with gentle to moderate southerly flow south of the convergence zone. Seas are 4 to 7 ft in a mix of S and NW swell across the open waters. For the forecast, the moderate SW swell across the equatorial waters will diminish today. The cold front will weaken as stall as it sags just south of 31N through the early part of the week, while associated northerly swell builds seas to around 8 ft north of it. Gradual development with the area of low pressure along the monsoon trough will be possible while it moves at 10 to 15 kt through the middle of the week. At the very least, winds may increase to fresh to strong with seas to around 8 ft. $$ Lewitsky