000 AXPZ20 KNHC 112214 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Jan 11 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. ...SPECIAL FEATURES... The San Cristobal Volcano in NW Nicaragua near 12.7N87.0W is emitting ash this afternoon. Satellite imagery shows a narrow plume of ash moving SW away from the volcano and out over the local waters to near 11N90W, creating a narrow plume about 30 nm wide. Ash may be reaching the surface under this ash cloud and an Ashfall Advisory has been issued. Mariners should exercise caution across this area, and are encouraged to report any ash or floating volcanic debris to the National Weather Service at 305-229-4425. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from the coast of Colombia near 05N76W to 04N80W to 06N93W to 05N101W. The ITCZ continues from 05N101W to 06N118W to beyond 05N140W. Widely scattered moderate convection is observed from 02.5N to 08N between 123W and 132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A small and weak ridge, centered on a 1021 mb high pressure near 26.5N117W, continues to dominate the waters west of Baja California, and is producing gentle to moderate N winds across nearshore waters of Baja California, and variable winds 10 kt or less across the outer waters. Large NW swell dominating the regional waters the past 36 hours is subsiding from north to south across the waters of Baja California, with seas of 8 to 10 ft south of 27N and 6-8 ft north of 27N. Seas will continue to subside this afternoon through tonight, falling to 5-7 ft by Sat morning. Another round of NW swell is expected to reach the northern coast of Baja California Norte and Guadalupe Island by Sat afternoon in association with the next cold front due to cross 30N140W Sat afternoon. This reinforcing long period swell event will cause seas to rebuild to between 7 and 10 ft for the waters adjacent to Baja California by Sun afternoon. Gulf of California: Gentle NW winds will cover most of the Gulf today beneath weak ridging overhead. Winds will then become variable less than 10 kt Sat and Sat night. A weakening cold front will move across the region from the west late Sat and Sat night. This may bring brief moderate to fresh westerly gap winds into the northern Gulf of California along 30N. Farther south, the long period NW swell continues to propagate through the Mexican offshore waters W of 95W. Variable winds of 10 kt or less currently prevail south of 20N to the waters offshore of Puerto Angel, with seas of 6-9 ft. This NW swell is mixing with shorter period NE swell emerging from the Gulf of Tehuantepec to create another area of seas 7-9 ft between the offshore waters south of Tehuantepec and 100W. This area of combined swell will decay and shift southward away from the Mexican offshore waters through Sun afternoon. The gale force N winds over the Gulf of Tehuantepec of the past few days have tapered off to around 25 kt this afternoon. Strong high pressure over the the western Gulf of Mexico is shifting E ahead of low pres moving E from the southern Rockies. Winds across Tehuantepec will increase again late tonight to around 30 kt then rapidly diminish to less than 20 kt by late Sat afternoon as winds in the Gulf of Mexico veer sharply to the south. The next Gulf of Tehuantepec gap wind event is forecast by the computer models to begin on Sat night, reaching gale force Sun night through early Wed. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh NE to E winds will prevail across the Gulf region, and become fresh to strong across and downstream of the Gulf of Papagayo each night through the weekend primarily from the nocturnal drainage flow. Gulf of Panama: Moderate to fresh northerly winds downstream to near 05N with seas to 6 ft will continue through the weekend. REMAINDER OF THE AREA... The gale force winds accompanying the cold front entering the far NW waters have decreased to 25 kt or less. The front extends from 30N124W TO 25N130W TO 22.5N140W this afternoon and will continue moving eastward and gradually dissipate offshore of Baja California by Sat evening. A new round of large, long period NW swell also accompanies the front. Morning altimeter data showed seas reaching as high as 19 ft in the wake of the front. As the front progresses eastward, seas across NW portions behind the front will subside gradually to 10-15 ft tonight and to 8-12 ft on Sat. Elsewhere, long period NW swell persists across the region west of 105W. Moderate to fresh trade winds are evident W of 125W between the ITCZ and 15N. Fairly dry conditions continue, and little shower or thunderstorm activity is observed in the vicinity of the ITCZ. $$ Stripling