000 AXPZ20 KNHC 290935 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jul 29 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 0600 UTC surface analysis and satellite imagery through 0845 UTC. ...SPECIAL FEATURES... Low pressure of 1007 mb is centered along the monsoon trough near 14N121W. Latest satellite imagery shows numerous moderate convection within 150 nm of the low in the SE quadrant. Scattered moderate convection is within 30 nm of 11N118W. The low remains fairly elongated as it being impinged upon by light northwest shear aloft attributed to an upper trough nearby. The latest ASCAT pass over the low indicated fresh to strong southwest winds in the southeast quadrant and fairly light to moderate winds on its northern periphery. This low pressure has a medium chance of becoming a tropical cyclone during the next 48 hours. Even it does not expect strong winds and seas to 8 to 9 ft near this low pressure over the next few days. A 1007 mb low is along the monsoon trough over the eastern part of the area near 12N106W. Latest satellite imagery shows that convection with it has increased during the overnight hours. This convection consists of scattered moderate to isolated strong type intensity within 180 nm of the low in the SE quadrant and within 150 nm of the low in the SW quadrant. Scattered moderate convection is displaced to the east of the low from 09N to 12N between 102W-104W. Similar activity is within 30 nm of 13N106W. An overnight ASCAT pass captured moderate to fresh southerly winds east of the low from 09N to 14N between 101W-104W. Presently seas are less than 8 ft near the low, but are expected to gradually build through late Fri and into the weekend. This low pressure has a medium chance of becoming a tropical cyclone during the next 48 hours. Please see the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details on both these systems. ...TROPICAL WAVES... A tropical wave over the far eastern part of the area has its along 80W north of 03N to across central Panama and into the southwestern Caribbean Sea. It is moving westward at 15 kt. Scattered moderate convection is within 60 nm either side of the wave from 07N to 08N. A tropical wave with its axis along 94W extends from far southeastern Mexico and the Gulf Tehuantepec region to near 05N. It is moving westward at 10 to 15 kt. The wave shows a signal at 700 mb. Large clusters of numerous moderate to strong convection have developed over southeastern Mexico during the past few hours and moved offshore out ahead of the wave from 14N-16N between 93W- 95W. Expect for this activity to remain active during the morning. Scattered moderate to isolated strong convection is within 180 nm east of the wave from 08N to 09N. A tropical wave has its axis along 108W from 03N to 16N, moving westward at 10-15 kt. No deep convection is noted with this wave. A tropical wave has its axis near 125W from 03N to 18N, moving westward at 10-15 kt. Only isolated showers and thunderstorms are evident within 120 nm either side of the wave axis from 09N to 11N. A tropical wave has axis along 138W from 03N to 16N. It is moving westward at 10-15 kt. Scattered moderate to isolated strong convection is noted from 08N to 16N between 138W and 140W, and also east of the wave from 08N to 13N between 130W- 137W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the coast of Colombia near 09N77W to across northern Panama and central Costa Rica. It continues to 11N97W to a 1007 mb low pressure near 12N106W to 10N114W and northwest to another 1007 mb low pressure near 14N121W and to 10N126W. The ITCZ continues from 10N126W to beyond 10N140W. In addition to the convection described in the Tropical Waves section above, scattered moderate to isolated strong convection is within 60 nm south of trough between 84W-86W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh north gap winds are pulsing across the Gulf of Tehuantepec, between relatively higher pressure to the north of the region and lower pressure farther south. Light to gentle variable winds are elsewhere with seas mainly to 3 to 5 ft due to a south to southwest swell. Farther north, a relatively weak pressure gradient supports gentle to locally moderate northwest winds over the Baja California offshore waters with seas in the 3 to 5 ft range in SW swell. For the forecast, high pressure north of the area and lower pressure farther south will support pulses of fresh gap winds across the Gulf of Tehuantepec and off western Oaxaca tonight. Mostly moderate winds and seas will persist elsewhere. Looking ahead, seas will build off southern Mexico starting late Sat due to increased southerly swell. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Gentle to moderate south to southwest winds will remain south of the monsoon trough through the forecast period along with a southwest swell that will build seas to 5-7 ft. Moderate to locally fresh northeast to east winds will continue over the Papagayo region and waters downstream from there through Sun, then diminish slightly Sun night into early next week. Seas of 3-6 ft due to a southwest swell will change little over Gulf of Papagayo region during the next few days. For the forecast, fresh to strong gap winds across the Gulf of Papagayo will diminish this afternoon, then pulse again tonight into Fri. Elsewhere, gentle to moderate south to southwest winds will dominate the waters south of the monsoon trough through the forecast period along with southwest swell. The tropical wave along 80W may help to increase instability over most of the Central American offshore waters through the next couple of days possibly leading to enhanced convection over those offshore waters. REMAINDER OF THE AREA... See the Special Features section above for details on two low pressure systems that have potential for tropical cyclone formation. Aside from the two Special Features low pressure systems, relatively weak high pressure is present with the associated gradient allowing for generally moderate northeast trades to persist north of the monsoon trough and moderate south to southwest winds farther south, with 5 to 7 ft seas in mixed swell in most areas. Larger southerly swell is noted south of the equator. Winds and seas over some sections of the area will be impacted by the Special Features low pressure systems during the next several days. $$ Aguirre