--------------------------------------------------------------------------- TROPICAL WEATHER DISCUSSION (EASTERN PACIFIC AREA) MESSAGES T1T2: AX A1A2: PZ Date: 2026-09-19 --------------------------------------------------------------------------- Message File: T_AXPZ20KNHC190400_C_KWBC_20260919040129_4522426-3979-TWDEP.txt ****0000006090**** AXPZ20 KNHC 190400 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0350 UTC. ...SPECIAL FEATURES... Western East Pacific: Low pressure, Invest EP98, is centered near 11N118W with a pressure of 1009 mb. This feature is part of a rather broad area of cyclonic circulation. Satellite imagery exhibits scattered moderate to isolated strong convection from 05N to 17N between 115W and 125W. Environmental conditions are conducive for development, and a tropical depression is likely to form this weekend as it moves westward at 10 to 15 mph across the western East Pacific. The low has a high chance of tropical cyclone formation through the next 48 hours and the next 7 days. South of Southwestern Mexico: A tropical wave, Invest EP99, has its axis extending from near 18N107W to 04N107W, with low pressure of 1009 mb, near 08N106W. This feature is part of a broad area low pressure that is located about 700 nautical miles south- southwest of the southwestern coast of Mexico. Satellite imagery depicts scattered moderate to isolated strong convection from 05N to 15N between 100W and 110W. Environmental conditions are conducive for development, and a tropical depression is likely to form late this weekend or early next week while it moves generally northward off the coast of southwestern Mexico. This system has a medium chance of tropical cyclone formation through the next 48 hours and a high chance of development within the next 7 days. Please refer to the latest NHC Tropical Weather Outlook at website: www.hurricanes.gov for more details on these Invests. ...TROPICAL WAVES... A tropical wave in the western Caribbean Sea with axis near 81W extends southward across Panama and its offshore waters. It is moving westward near 15 kt. Numerous moderate to strong convection is from 02N to 10N between 77W and 85W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N83W to 08N100W to 12N120W to 17N137W to 15N140W. Scattered moderate to isolated strong convection is from 03N to 13N between 90W and 100W, and from 09N to 21N between 125W and 135W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a ridge over the Gulf of America and the eastern extension of the Pacific monsoon is supporting fresh to strong N gap winds across the Gulf of Tehuantepec. Seas with these winds are 6 to 8 ft. Scattered showers are over the offshore waters between Chiapas and Oaxaca due to a broad area of low pressure and the monsoon south of the region. The gradient related to high pressure west of the Baja California offshores and low pressure along western Mexico is supporting fresh to locally strong NW winds N of Cabo San Lazaro. Moderate or weaker winds are elsewhere along with moderate seas, except for slight seas in the Gulf of California. For the forecast, winds will pulse to fresh to strong speeds in the Gulf of Tehuantepec tonight becoming moderate N to NE winds Sat afternoon. Fresh to strong NW winds offshore Baja California will diminish Sat afternoon. Northwest winds over these waters are expected to briefly reach fresh speeds Mon night into Tue. Otherwise, the environmental conditions of Invest EP99, near 08N106W, are conducive for development and a tropical depression is likely to form late this weekend or early next week while it moves generally northward off the coast of southwestern Mexico. Regardless of development, this system is forecast to bring fresh to strong winds and moderate to rough seas to the Michoacan and Jalisco offshores Tue night into the middle part of next week. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh NE to E winds are across the Gulf of Papagayo extending downstream to near 88W. Moderate or weaker winds prevail elsewhere, except for strong to gusty winds likely ongoing across the W Panama and Costa Rica offshores due to strong convective activity associated with a tropical wave. Seas over the offshore waters are of moderate state due to a long- period southwest swell. For the forecast, the pressure gradient between the ridge north of the area and the eastern Pacific monsoon will support pulsing fresh to occasionally strong easterly winds and moderate to rough seas across the Papagayo region into early Sat, then pulsing to moderate to fresh speeds through early Sun. Moderate winds and seas will prevail elsewhere. ...REMAINDER OF THE AREA... The remnant 1008 mb low of former Tropical Depression Fifteen-E is located near 17N137W. A tight gradient between the low and high pressure of 1024 mb to its north is bringing fresh to strong northeast to east winds over the waters from 16N to 26N west of 124W. Seas are 6 to 9 ft within this area of winds. Satellite imagery shows scattered moderate isolated strong convection from 10N to 21N between 126W and 135W. Elsewhere, winds are moderate or weaker for the most part and seas are of moderate state, except for rough state seas in the vicinity of Invest EP98. For the forecast, see the Special Features section. Otherwise, environmental conditions appear conducive for some development of this system next week as it moves westward to west- southwestward, and a tropical depression could form well to the south or southeast of the Hawaiian Islands by the middle to latter part of next week. $$ Ramos ########################### END OF MESSAGE SET ############################ --------------------------------------------------------------------------- Message File: T_AXPZ20KNHC190920_C_KWBC_20260919092043_31523192-4028-TWDEP.txt ****0000005834**** AXPZ20 KNHC 190920 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0920 UTC. ...SPECIAL FEATURES... Western East Pacific: Low pressure, Invest EP98, is centered near 12N119W with a pressure of 1009 mb. This feature is part of a rather broad area of cyclonic circulation. Satellite imagery exhibits scattered moderate to isolated strong convection from 04N to 17N between 118W and 135W. Environmental conditions are conducive for development, and a tropical depression is expected to form this weekend as it moves westward to west-northwestward at 10 to 15 kt across the western East Pacific. The low has a high chance of tropical cyclone formation through the next 48 hours and the next 7 days. South of Southwestern Mexico: A tropical wave, Invest EP99, has its axis extending from near 18N108W to 04N107W, with low pressure of 1009 mb, near 09N106W. This feature is part of a broad area low pressure that is located about 700 nautical miles south- southwest of the southwestern coast of Mexico. Satellite imagery depicts scattered moderate isolated strong convection from 05N to 15N between 99W and 112W. Environmental conditions are conducive for development, and a tropical depression is expected to form late this weekend or early next week while it moves generally northward off the coast of southwestern Mexico. This system has a high chance of tropical cyclone formation through the next 48 hours and a high chance of development within the next 7 days. Please refer to the latest NHC Tropical Weather Outlook at website: www.hurricanes.gov for more details on these Invests. ...TROPICAL WAVES... A tropical wave in the western Caribbean Sea with axis near 82W extends southward across W Panama and its offshore waters. It is moving westward near 15 kt. Numerous moderate to isolated strong convection is from 05N to 10N between 80W and 89W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N84W to 09N106W to 12N120W to 15N136W. Scattered moderate to isolated strong convection is from 03N to 16N between 90W and 100W, and from 07N to 20N between 130W and 138W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between a ridge over eastern Mexico and the eastern extension of the Pacific monsoon is supporting fresh N gap winds across the Gulf of Tehuantepec. Seas with these winds are 5 to 6 ft. Scattered showers are over the offshore waters between Oaxaca and Guerrero due to Invest EP99 and the monsoon south of the region. The gradient related to high pressure west of the Baja California offshores and low pressure along western Mexico is supporting fresh to locally strong NW winds N of Cabo San Lazaro. Moderate or weaker winds are elsewhere along with moderate seas, except for slight seas in the Gulf of California. For the forecast, winds will pulse to fresh to strong speeds in the Gulf of Tehuantepec becoming moderate N to NE winds this afternoon. Fresh to 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, the environmental conditions of Invest EP99, near 09N106W, are conducive for development and a tropical depression is expected to form late this weekend or early next week while it moves generally northward off the coast of southwestern Mexico. Regardless of development, this system is forecast to bring fresh to near gale-force winds and moderate to rough seas to 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 NE to E winds are across the Gulf of Papagayo extending downstream to near 88W. Moderate or weaker winds prevail elsewhere, except for strong winds likely ongoing across the W Panama and Costa Rica offshores due to strong convective activity associated with a tropical wave. Seas over the offshore waters are slight to moderate in long-period southwest swell. For the forecast, moderate to fresh NE to E winds will pulse in Papagayo through early Sun. Moderate winds and seas will prevail elsewhere. ...REMAINDER OF THE AREA... The remnant 1008 mb low of former Tropical Depression Fifteen-E is located near 16N138W. A tight gradient between the low and high pressure of 1026 mb to its north is bringing fresh to strong northeast to east winds over the waters from 16N to 26N west of 121W. Seas are 6 to 9 ft within this area of winds. Satellite imagery shows scattered moderate isolated strong convection from 07N to 20N between 130W and 138W. Elsewhere, winds are moderate or weaker for the most part and seas are of moderate state, except for moderate to fresh winds in the vicinity of Invest EP99. For the forecast, see the Special Features section. Otherwise, environmental conditions appear conducive for some development of Former TD 15-E next week as it moves westward to west- southwestward, and a tropical depression could form well to the south or southeast of the Hawaiian Islands by the middle to latter part of next week. $$ Ramos ########################### END OF MESSAGE SET ############################ --------------------------------------------------------------------------- Message File: T_AXPZ20KNHC191509_C_KWBC_20260919151046_31523192-4048-TWDEP.txt ****0000005367**** AXPZ20 KNHC 191509 TWDEP 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. $$ AL ########################### END OF MESSAGE SET ############################