Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Sat Sep 19 2026 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. ...SPECIAL FEATURES... Western East Pacific (EP98): Disorganized showers and thunderstorms continue to persist in association with an area of low pressure located well southwest of the southern tip of the Baja California Peninsula. Environmental conditions are conducive for development, and a tropical depression is expected to form over the next several days as it moves westward to west- northwestward at 10 to 15 mph across the western East Pacific. There is a high chance of tropical cyclone formation in the next 48 hours. South-Southwest of Southwestern Mexico (EP99): Recent satellite- derived wind data show that the area of low pressure located well south- southwest of the southwestern coast of Mexico is still elongated, and the shower and thunderstorm activity remains disorganized. However, environmental conditions are conducive for development, and a tropical depression is expected to form over the next couple of days as the system moves generally northward off the coast of southwestern Mexico. Interests along the southwestern and west- central coast of Mexico should monitor the progress of this system. There is a high chance of tropical cyclone formation in the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at website: www.hurricanes.gov for more details on these Invests. ...TROPICAL WAVES... The axis of a tropical wave is near 108W. Please see SPECIAL FEATURES above for more on EP99, which developed from this tropical wave. A tropical wave is moving across the western Caribbean Sea with axis near 81W extends southward across Panama and its offshore waters. It is moving westward near 10 to 15 kt. Nearby convection is discussed in the ITCZ/monsoon trough section below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 11N86W to 10N106W to 07N114W to 17N140W. Scattered moderate and isolated strong convection is noted from 03N to 11N east of 100W, and from 06N to 17N between 100W and 110W, and from 07N to 17N between 120W and 132W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see SPECIAL FEATURES above for more in EP99, with a high chance for TC development in the next 48 hours. Moderate to fresh winds, and moderate seas, prevail over the Gulf of Tehuantepec, as well as west of the Baja California peninsula. Light to gentle winds, and slight seas, are in the Gulf of California. Elsewhere, light to gentle winds, and moderate seas, prevail. For the forecast, fresh to locally strong NW winds offshore Baja California will diminish this afternoon. Northwest winds over these waters are expected to briefly reach fresh speeds again Mon night into Tue. Otherwise, Invest EP99 is centered near 10N106W. Environmental conditions are conducive for development, and a tropical depression is expected to form over the next couple of days as the system moves generally northward off the coast of southwestern Mexico. Regardless of development, this system is forecast to bring increasing winds and seas over the Michoacan and Jalisco offshores tonight into Wed night. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to locally fresh NE to E winds are across the Gulf of Papagayo extending downstream to near 88W. Moderate or weaker winds prevail elsewhere. Moderate seas are over the offshore waters in long-period southwest swell. For the forecast, moderate to fresh NE to E winds will pulse in the Papagayo region through early Sun. Moderate winds and seas will prevail elsewhere. ...REMAINDER OF THE AREA... Please see SPECIAL FEATURES above for more in EP99, with a high chance for TC development in the next 48 hours. The remnant low of former Tropical Depression Fifteen-E is located near 16N140W. A second area of low pressure, EP98, is centered near 11.5N121.5W. Both of these features are embedded within the monsoon trough. The pressure gradient between these features and a 1024 mb high centered N of the area near 34N136W is supporting moderate to fresh, locally strong winds, N of the monsoon trough to near 25N and W of 119W. Moderate to rough seas cover these waters. Elsewhere, moderate winds and moderate seas are N of the monsoon trough. Moderate to fresh winds southerly winds are feeding into EP99, where moderate seas are building. Elsewhere S of the monsoon trough, light to gentle winds, and moderate seas, prevail. For the forecast, the remnant low of TD Fifteen-E will move W of the area today. Outside of conditions with EP98 and EP99, gentle to moderate winds and moderate seas will prevail.