Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Thu Jun 18 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 1800 UTC surface analysis and satellite imagery through 2000 UTC. ...TROPICAL WAVES... A tropical wave is along 85W from 01N northward to across portions of Costa Rica, Nicaragua and Honduras, continuing into the NW Caribbean Sea. This wave is moving at around 10 kt. Any nearby convection is described with the monsoon trough below. A tropical wave is along 94.5W from 01N northward to the Gulf of Tehuantepec, moving very slowly westward at around 5 kt. Any nearby convection is described with the monsoon trough below. A tropical wave is along 113W from 01N northward to 19N near the Revillagigedo Islands, moving very slowly westward around 5 kt. Any nearby convection is described with the monsoon trough below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from the SW Caribbean Sea to across portions of Panama and Costa Rica into the Pacific near 09N84W to 14N104W to 07N124W. The ITCZ extends from 07N124W to beyond 06N140W. Isolated to widely scattered moderate convection is noted within 180 to 240 nm either side of the monsoon trough and ITCZ across the majority of those waters, somewhat enhanced by the tropical waves noted above. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough is analyzed from near SW Arizona southeastward to along the Gulf of California to near Cabo San Lucas while ridging is west of Baja California. This pressure pattern is supporting gentle to moderate NW-N winds across the waters offshore the peninsula as well as in the Gulf of California. A weak pressure gradient exists elsewhere and to the south resulting in mainly gentle winds offshore the remainder of Mexico. Seas are moderate at 4-6 ft heights in mainly long period S-SW swell. In the Gulf of California, seas are mainly 1-3 ft. Some convection is present offshore and near southern Mexico mainly due to a passing tropical wave near the Gulf of Tehuantepec. Winds and seas may be higher in or near any convection. For the forecast, gentle to moderate winds will continue over the offshore waters of Baja California, except pulsing to locally fresh speeds at night through through the weekend. Gentle to occasionally moderate winds are expected inside the Gulf of California and near the tip of Baja California Sur through the weekend and into early next week. Light to gentle winds will prevail over the waters between Cabo Corrientes and Tehunatepec during the forecast period. Moderate seas in mainly southerly swell change little into early next week. Seas will be mainly slight in the Gulf of California. Looking ahead, gap winds in the Gulf of Tehuantepec may pulse to fresh to strong starting late Tu night. ....OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate offshore easterly winds are in the Gulf of Papagayo. Gentle to moderate SE-S winds are found offshore Ecuador to the Galapagos Islands. Light to gentle variable winds are found across the remainder of the waters. Seas are moderate at mainly 4-6 ft in S-SW swell, except 3-4 ft offshore western Colombia. Some widely scattered showers and isolated thunderstorms are present across much of the offshore waters near the monsoon trough. Winds and seas may be higher in or near any convection. For the forecast, gentle to occasionally moderate southeast to south winds and moderate seas will prevail across the offshore waters between Ecuador and the Galapagos Islands through early next week. Moderate winds will pulse to fresh speeds in diurnal offshore flow in the immediate Gulf of Papagayo through at least Tue night. Light to gentle winds and slight to moderate seas in southwest swell are forecast elsewhere through the next several days. ...REMAINDER OF THE AREA... A weak ridge extends along 26N with NE to SW troughing from southern California to near 30N130W. This pressure pattern combined with lower pressures to the south associated with the monsoon trough and ITCZ supports a belt of moderate to locally fresh trades from 09N to 20N west of 120W. Elsewhere north of the monsoon trough and ITCZ, winds are mainly gentle to locally moderate. South of the monsoon trough and ITCZ, mainly gentle to moderate southerly winds prevail. Seas are 7-9 ft across the waters south of 06N between 101W and 121W in southerly swells, and mainly 5-7 ft across the remainder of the waters dominated by long period S-SW swell, mixed with SE swell E of 115W. Seas are locally fresh in the belt of moderate to fresh trades. Widely scattered showers and isolated thunderstorms as described above can be found on either side of the monsoon trough and ITCZ. Winds and seas may be higher in or near any convection. For the forecast, the old southerly swell across the south- central waters will gradually decay through the end of the week, then, seas will build to rough again south of and near the Equator and east of 120W beginning Sat as a new set of southerly swell begins to move through this part of the area. Winds may pulse to fresh speeds in the west-central waters at times. Otherwise, little overall changes are expected in and winds and seas through the upcoming weekend and into early next week.