000 AXPZ20 KNHC 110935 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 631 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Gale Warning: Gale force northerly winds continue across the Gulf of Tehunatepec are expected to persist through the morning. Currently, gales to around 35 kt extend southward from the coast to near 14N95.5W, with peak seas up to 13 ft. This gap wind event is being driven by strong high pressure across the western Gulf of Mexico. Winds will rapidly diminish to 30 kt or less around after sunrise, and to less than 20 kt by late 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. Please see the latest High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. Gale Warning: Winds to gale force accompany a cold front reaching from 30N135W to 27N140W. Recent ship observations along with earlier scatterometer data indicate winds to gale force within 120 nm of both east and west of the front north of 29N. A new round of large, long-period NW swell also accompanies the front. Recent altimeter data shows seas reaching as high as 18 ft in the wake of the front, and may be reaching as high as 22 ft currently. Winds will diminish below gale through the night into the morning as the front weakens. Seas will subside slightly as well although swell of 12 to 15 ft will still linger through the next 24 hours over waters north of 20N and west of 120W. The front is expected to dissipate Sat afternoon across central portions of Baja California and the northern Gulf of California. See the latest High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. .INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from the coast of Colombia near 04.4N77W to 01N80W to 05N96W. The ITCZ continues from 05N96W to 07N125W to beyond 06N140W. No significant shower or thunderstorm activity is observed. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak ridge, anchored by 1021 mb high pressure near 28N121W, continues to dominate the waters west of Baja California, and is producing gentle to moderate NW to N winds across offshore waters of Baja California. Large NW swell associated with a low pressure system that moved into northern California is dominating the area offshore and nearshore waters of Baja California with seas of 9-12 ft. Seas will subside very slowly through early Sat, just ahead of another group of NW swell expected to reach the northern coast of Baja California Norte and Guadalupe Island by Sat afternoon. This long period swell event will create dangerous surf conditions along the coasts and outer reefs of Baja California through today, producing strong rip currents in the surf zone, and localized areas of coastal erosion. Gulf of California: Gentle NW winds are expected across most of the Gulf through Fri under the weak ridge west of Baja, and then become variable less than 15 kt into Sat. 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 NW swell is moving into the Mexican offshore waters east of 120W, eventually mixing with shorter period NE swell emerging from the Gulf of Tehuantepec. Much of this will shift south of the Mexican offshore waters through Sat. 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... A strong cold front has moved into the far NW part of the forecast area this afternoon and evening and extends from 30N131W TO 26N140W, and will continue eastward tonight. This will bring gale force winds and reinforcing large long period NW swell to the region. The front will weaken as it moves eastward into Baja California through Sat. Elsewhere, long period NW swell persists across the region north of 10N and west of 120W. Fresh trade winds are evident farther south, converging into the ITCZ. Fairly dry conditions continue, and little shower or thunderstorm activity is observed. $$ Christensen