000 AXPZ20 KNHC 080921 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Fri Nov 8 2024 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 0900 UTC. ...SPECIAL FEATURES... Excessive Rainfall Risk in Southern Central America: The combination persistent SW flow bringing rich, deep-layer moisture along with divergent flow aloft will support the potential for heavy rainfall across southern Central America into early next week. This may particularly impact Costa Rica, where rainfall amounts may be in excess of 20 inches (500 mm) through Tue. Rainfall amounts as high as 10 inches (250 mm) may impact Panama through Tue as well. This information is provided by the Weather Prediction Center's International desk team. Please refer to your national weather agency for details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from near the border of Guatemala and El Salvador near 14N90W to to 1010 mb low pressure near 11N104W, to 1011 mb low pressure near 14N115W, to 1011 mb low pressure near 10N128W to 10N140W. Scattered moderate convection is active with in 90 nm off the coast of Costa Rica and western Panama. Scattered moderate convection is also evident from 10N to 13N between 100W and 105W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A recent scatterometer satellite pass confirmed fresh to strong NW winds across the southern Gulf of California overnight, between low pressure over north-central Mexico, and higher pressure west of the region. A concurrent altimeter satellite pass indicated combined seas of 6 ft just north of the main plume of winds, hinting that seas are likely up to 8 ft farther south over the Gulf of California where the fetch is greater. Although not captured in the scatterometer pass, it is likely there are plumes of fresh to strong easterly gap winds across the Baja California peninsula into the adjacent Pacific waters, primarily near Punta Eugenia. Farther south, the scatterometer also sampled fresh northerly gap winds across the Gulf of Tehuantepec. Gentle to moderate winds persist elsewhere across the Mexican offshore waters, with moderate combined seas in NW swell. For the forecast, the fresh to strong NW to N winds and moderate to rough seas across the southern Gulf of California into Sat, with the winds filtering through Baja California passages this morning. Moderate to fresh N winds are pulsing across the Gulf of Tehuantepec mainly at night from late Sat through late Mon. Mainly gentle to moderate winds will prevail elsewhere, possibly freshening offshore Baja California north of Cabo San Lazaro Mon night through Tue. Meanwhile, seas of 4 to 7 ft in the open waters are forecast to persist into early next week, building north of Cabo San Lazaro with the freshening winds Mon night into early Tue. Looking ahead, a significant and large NW swell event may arrive offshore Baja California Norte by mid- week. ...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please refer to the Special Features section for details on an Excessive Rainfall Risk in Southern Central America. A modest surge in SW flow of southern Central America is supporting scattered showers and thunderstorms off the coast of western Panama and Costa Rica. Earlier altimeter data indicated wave heights to 8 ft off Panama, Colombia and Ecuador, likely with a component of SW swell. Gentle to moderate breezes and moderate seas are noted elsewhere. For the forecast, the moderate to fresh SW winds and large SW swell will continue impact the offshore waters of Panama into Sat, with moderate to fresh winds pulsing again into Costa Rica Sun and Mon. Farther south, large SW swell off Ecuador and Colombia will subside today. Mostly moderate winds and seas will persist elsewhere. ...REMAINDER OF THE AREA... A scatterometer pass indicated fresh to strong winds ongoing near the remnant low that was Fourteen-E 11N104W, although the wind and cloud pattern indicate this feature is becoming more disorganized along the monsoon trough. A few showers and thunderstorms are still active near the low pressure. Two additional areas of weak low pressure are noted along the monsoon trough near 115W and 128W. A weak trough is analyzed farther north along 125W north of 22N. This is breaking up the subtropical ridge in the area, which in turn is allowing mostly gentle to moderate breezes farther south across the region. A large area of 7 to 9 ft combined seas persist over the tropical Pacific waters south of 15N between 95W and 130W, in a combination of northerly and southerly swell. Farther north, combined seas of 6 to 8 ft are evident north of 25N between 125W and 135W in northerly swell. Moderate combined seas are noted elsewhere. For the forecast, the weak lows along the monsoon trough will become less defined through Sat with winds across the open waters west of 120W mainly gentle to moderate. Winds are forecast to increase slightly to moderate to fresh north of the monsoon trough and west of 120W thereafter into early next week as high pressure builds in across those waters in the wake of a dying cold front passing by mainly north of 30N. Meanwhile, moderate to fresh winds will be south of the monsoon trough to about the Equator through the upcoming weekend with seas of around 8 ft there. A new set of NW swell will push southeast of 30N140W into early Sat, with seas of 7 to 9 ft west of a line from 30N120W to 10N140W by early Sun. Those seas will decay thereafter. Looking ahead, a larger and more significant set of NW swell may impact the region north of 10N and west of 125W from late Mon night through mid-week. $$ Christensen