000 AXPZ20 KNHC 132125 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2125 UTC Fri Dec 13 2019 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 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. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N85W to 05N105W. A segment of the intertropical convergence zone continues from 05N105W to 09N110W. Another segment of the ITCZ reaches from 07N130W to beyond 08N140W. Scattered moderate isolated strong convection was noted from 10N to 12N between 94W and 97W. Scattered moderate convection was also noted from 13N to 15N between 117W and 119W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... In the Gulf of Tehuantepec, a weak pressure pattern north of the area is maintaining moderate to fresh gap into the Gulf of Tehuantepec. Winds will increase slightly overnight into early Sat morning due to a combination of weak high pressure building over the southwest Gulf of Mexico, and local overnight drainage flow. Winds will diminish as the high pressure shifts eastward through Sat, although pulses to 20 kt are possible Sat night and Sun night. Looking ahead, The next major cold front will move through southern Mexico by Tue. Early indications from various model data show near storm strength gap winds by mid week, with strong gap winds and building seas reaching as far as 360 nm downstream into open waters. Farther north, recent ship observations confirmed fresh winds off the coast of Cabo Corrientes, between high pressure over the central plateau over central Mexico and lower pressure off the Pacific coast of southern Mexico. These winds should diminish overnight as the high pressure weakens. The pressure gradient between a ridge anchored by a 1029 mb high near 30N134W and a trough across the Gulf of California is maintaining gentle to moderate northerly flow off the coast of Baja California, with moderate to fresh NW winds across the Gulf of California. Low pressure will develop over Mexico early on Sat, with a tightening of the pressure gradient supporting increasing winds fresh to strong north of Punta Eugenia Sat evening. Strong winds will spread south to near Cabo San Lazaro before diminishing early on Mon. Long period NW swell in excess of 8 ft will continue through the offshore waters of Baja California and reach the Revillagigedo Islands by Sat night. High pressure will build over the Great Basin on Monday evening and will support fresh to near gale force N flow over the Gulf of California through Thu morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh winds are expected across the Gulf of Papagayo through the forecast period. Elsewhere, gentle to moderate south to southwest monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador through Sat night, while light to gentle flow is across the Gulf of Panama. REMAINDER OF THE AREA... The pressure gradient between a 1029 mb high pressure center located near 30N134W two areas of low pressure, centered near 11N119W and 09N130W is supporting fresh to strong trade winds across the waters from 07N and 20N and west of 115W. NW swell is propagating across the forecast waters, with seas in the 8 to 13 ft range north of 05N and west of 115W. The NW swell will continue across the forecast waters, with seas 8 ft or greater covering the waters north of 07N and west of 110W through the weekend. A fresh set of NW swell will move into the northwest waters early next week, with seas building in excess of 8 ft to as high as near 20 ft by midweek. $$ Christensen