


Tropical Weather Discussion
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Issued by NWS
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945 AXPZ20 KNHC 162201 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Oct 16 2025 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 2130 UTC. ...SPECIAL FEATURES... South of Southern Mexico (Invest EP91): A broad area of low pressure is producing some disorganized showers and thunderstorms offshore of southern Mexico, generally from 11N to 16N between 94W and 102W. Environmental conditions appear conducive for gradual development of this disturbance, and a tropical depression could form during the next couple of days or so. The system is forecast to move slowly west-northwestward or northwestward near the coast of southern and southwestern Mexico through the weekend. There is a medium chance of tropical development within the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N78W to 08N82W to EP91 centered near 12N98W to a 1012 mb low near 07N135.5W to 09N140W. Scattered moderate convection is occurring from 06N to 13N between 84W and 90W. Widely scattered convection is noted from 09N to 12N between 100W and 115W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for information on EP91 and the potential tropical development off the coast of southern Mexico. Earlier scatterometer satellite data showed fresh to locally strong N to NE gap winds were occurring in the Gulf of Tehuantepec as a 1012 mb high prevails over east-central Mexico. Elsewhere, ridging extends over the Baja California waters, stemming from a 1031 mb high centered northwest of the area near 37N141W. The pressure gradient between this ridge and a surface trough extending from northwestern Mexico to 18N107W is supporting moderate to locally fresh NW winds, as noted via scatterometer data, and 5 to 8 ft seas over the Baja waters. In the northern Gulf of California, moderate to fresh NW winds and 2 to 4 ft seas are noted, with gentle to moderate winds and 1 to 3 ft seas occurring in the central and southern Gulf. Mainly moderate NW winds and 5 to 6 ft seas are noted offshore of southwestern Mexico. For the forecast, fresh N to NE winds in the Gulf of Tehuantepec will diminish through this afternoon. Elsewhere, moderate to occasionally fresh NW winds and locally rough seas will prevail offshore of Baja California through Fri morning. Pulsing moderate to fresh NW winds will also be possible in the northern Gulf of California through this evening. Looking ahead, a broad area of low pressure, EP91, is centered offshore of southern Mexico. Environmental conditions appear conducive for gradual development of this disturbance, and a tropical depression could form during the next couple of days or so. The system is forecast to move slowly west-northwestward or northwestward near the coast of southern and southwestern Mexico through the weekend. There is a medium chance of tropical development within the next 48 hours. Regardless of development, increasing winds and building seas are possible offshore of southern Mexico through this weekend. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Recent scatterometer satellite data showed moderate to locally fresh SW winds and 5 to 6 ft seas were occurring well offshore of Guatemala as EP91 prevails offshore of southern Mexico. Mainly moderate S to SW winds and 4 to 5 ft seas are noted elsewhere south of the monsoon trough. To the north, light to gentle winds and 3 to 4 ft seas prevail. For the forecast, fresh to occasionally strong SW winds and locally rough seas are expected in association with EP91 well offshore of Guatemala through Fri night. Otherwise, moderate SW winds and moderate seas will occur south of the monsoon trough into early next week, with gentle winds and moderate seas prevailing to the north. ...REMAINDER OF THE AREA... A 1031 mb high centered northwest of the area near 37N141W extends ridging over the eastern Pacific waters north of the monsoon trough. Moderate to fresh N to NE winds are noted via scatterometer data in this region, and rough seas of 8 to 9 ft in N swell are noted north of 15N. Elsewhere, moderate to fresh SW winds are occurring north of 03N and east of 110W in association with EP91. Mainly moderate S to SE winds and 5 to 7 ft seas are occurring elsewhere south of the monsoon trough. For the forecast, moderate to occasionally fresh N to NE winds and rough seas will occur north of the monsoon trough into this weekend as high pressure prevails to the north. Winds will diminish slightly for the second half of the weekend. A new NW swell will support rough seas north of 25N Fri night through Sun morning. Elsewhere, fresh to occasionally strong SW winds and locally rough seas will occur in association with EP91 north of 03N and east of 110W into early Sat. Looking ahead, increasing winds and building seas are expected over the northern waters early next week as a weakening cold front moves southward along the California coast. $$ ADAMS