000 AXPZ20 KNHC 281603 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Jul 28 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... A tropical wave with its axis along 90W extends from Guatemala to and to near 05N. It is moving westward at 5-10 kt. Scattered moderate to isolated strong convection is noted from 05N to 08N between 88W and 92W, and from 11N to 15N between 92W and 95W. A tropical wave has its axis along 106W from 03N to 15N, moving westward near 15 kt. Scattered moderate to isolated strong convection is from 09N to 15N between 100W and 106W. A tropical wave has its axis near 121W from 03N to 18N, moving westward at 10 to 15 kt. Scattered moderate convection from 10N to 12N between 121W and 123W. A tropical wave has axis along 135W from 03N to 15N. It is moving westward at 10-15 kt. Scattered moderate to isolated strong convection is noted from 08N to 10N between 131W and 134W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N77W to 1008 mb low pressure near 10N106W to 1007 mb low pressure near 13N119W to 10N125W. The ITCZ continues from 10N125W to beyond 10N140W. In addition to the convection described in the Tropical Waves section above, scattered moderate to isolated strong convection is evident from 11N to 13N between 117W and 119W, and from 09N to 11N west of 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh north gap winds are pulsing across the Gulf of Tehuantepec this morning. Light to gentle variable winds are elsewhere with seas mainly to 3 to 5 ft. A few showers and thunderstorms are active off the Chiapas and eastern Oaxaca coasts, but this activity is diminishing. Isolated thunderstorms remain active off Guerrero. 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 4 ft range in SW swell. The earlier fresh northeast winds gap winds in the Gulf of Tehuantepec have ended for the time being, with winds there presently being of light to gentle speeds and east to southeast in direction along with seas of 4-6 ft due to a south to southwest swell. For the forecast, a tighter pressure gradient will develop along the Gulf of California beginning late this afternoon or evening allowing for moderate to locally fresh northwest winds to develop over the Baja California offshore waters through Sat. Moderate southeast winds will also develop along the Gulf of California Thu night through Fri night. 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. Seas of 3-6 ft due to a southwest swell will change little over Gulf of Papagayo region during the next few days. The weather over the offshore waters of Costa Rica and Colombia will be unsettled over the next few days due to instability associated with passing tropical waves. REMAINDER OF THE AREA... Showers and thunderstorms continue to become a little better organized near an area of low pressure centered along the monsoon trough near 19N118W. An earlier scatterometer satellite pass showed fresh to strong SW winds converging into the low pressure on the southern periphery. There is a medium chance this may develop into a tropical cyclone over the next five days at it tracks westward. Even if it does not, expect strong winds and seas to 8 to 9 ft near this low pressure over the next several days. Elsewhere, several tropical waves are across the region enhancing convection along and near the monsoon trough and ITCZ area. Aside from the convection, these waves are supporting moderate to locally fresh northeast to east winds from 10N to near 20N and west of about 115W, with seas in the 5-7 ft range. Weak high pressure present north of 20N and to the west of 120W supports gentle to moderate north to northeast winds along with seas to 5 ft due to a south swell. $$ Christensen