000 AXPZ20 KNHC 082114 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Excessive Rainfall Risk in Southern Central America: Persistent SW flow in the eastern Pacific region will bring rich, deep-layer moisture across southern Central America. This combined with a diffluent pattern aloft and the developing of a Central America Gyre (CAG) will support the potential for heavy rainfall across southern Central America into early next week. This weather pattern may particularly impact Costa Rica and Panama. Rainfall amounts may be in excess of 20 inches (500 mm) in central Costa Rica through Tue. Rainfall amounts of 10 to 12 inches (250-300 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 1011 mb low pressure near 11N103W, to 1011 mb low pressure near 13N114W, to 1011 mb low pressure near 10N128W to 1011 mb low pressure near 11N137W to 11N140W. Scattered moderate to isolated strong convection is noted from 05N to 11N between the coast of Colombia and 86W. Similar convective activity is also occurring from 08N to 11N between 100W and 105W, and from 09N to 12N between 89W and 91W. Scattered moderate convection can be found from 09N to 12N between 120W and 128W. ...OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Recent satellite derived wind data indicate fresh to strong NW winds across the Gulf of California S of 29N to the vicinity of San Jose del Cabo. Strong high pressure of 1030 mb over the Great Basin of U.S. supports these wind speeds. Moderate easterly gap winds are seen across the Baja California peninsula into the adjacent Pacific waters, primarily near Punta Eugenia. Farther south, the scatterometer also sampled moderate 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 seas across the southern Gulf of California will persist through Sat morning, with the winds spreading beyond the entrance to the Gulf tonight. Mainly gentle to moderate winds will prevail elsewhere, possibly freshening offshore Baja California north of Cabo San Lazaro Mon night through Tue as high pressure west of the area strengthen some. 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. Recent scatterometer data show an area of fresh to locally strong S to SW winds affecting the waters from 02N to 06N between 79W and 87W where seas are in the 8 to 9 ft range. These winds are transporting abundant tropical moisture across southern Central America, supporting an area of moderate to isolated strong convection from 05N to 11N between the coast of Colombia and 86W. Scattered showers and thunderstorms are noted over parts of Costa Rica and Panama, but more concentrated over eastern Panama. Gentle to moderate breezes and moderate seas are noted elsewhere. For the forecast, 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 across the offshore forecast waters of Costa Rica and western Panama Sun and Mon. Seas are forecast to build to 8 or 9 ft within these winds. Mostly moderate winds and seas will persist elsewhere. ...REMAINDER OF THE AREA... Several weak low pressure areas are noted along the monsoon trough. The pressure gradient between high pressure to the N and lower pressures in the vicinity of the monsoon trough supports a couple of areas with moderate to locally fresh N to NE winds, particularly S of 14N between 120W and 124W, and from 12N to 16N W of 132W. Elsewhere across the waters N of 15N and W of 120W, mainly light to gentle winds prevail with seas generally of 4 to 7 ft primarily in NW swell. Seas to 8 ft are spreading across the far NW corner of the forecast region in the wake of a cold front that has just moved SE of 30N140W. A weak surface trough is analyzed across the northern forecast waters, and extends from 30N129W to 20N125W. Scatterometer data captured the wind shift associated with the trough axis. This feature is breaking up the subtropical ridge in the area. 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 begin to propagate across the NW waters this evening, with seas of 8 to 10 ft N of 23N and NW of a line from 30N130W to 23N136W on Sat. Seas will subside to less than 8 ft by late Sun. Looking ahead, a larger and more significant swell event may impact the forecast region from late Mon night through mid-week, with seas likely building to 12 to 14 ft across the waters N of 27N. $$ GR