000 AXPZ20 KNHC 131524 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1310 UTC Sun Jan 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning...High pressure building N of the region behind a cold front moving across the western Gulf of Mexico is supporting strong to minimal gale force winds through the Gulf of Tehuantepec. Northerly winds are expected to further increase to 35-40 kt by early Mon morning. This gale force wind event is forecast to continue through Tue night. Strong northerly gap winds will continue to pulse through Thu night, then gradually diminish as the high pressure weakens and shifts east of the Gulf. Seas will build as high as 16 ft in the area of gale force winds, with NE swell in excess of 8 ft propagating as far as 105W by early Tue morning, and mix with longer period NW and SW swell through early next week. For more information, see the East Pacific High Seas Forecast under WMO/AWIPS headers FZNT02 KNHC/HSFAT2. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from a 1010 mb low pressure over Colombia near 06N76W to 04N84W to 05N90W to 04N96W. The ITCZ continues from 04N96W to 07N110W to beyond 04N140W. No significant convection is observed. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weakening cold front will move across Baja California and the Gulf of California this morning then become diffuse. Long period NW swell of 8 to 11 ft accompanying the front will move throughout the offshore waters of Baja California and the western Revillagigedo Islands through late today. The swell will largely subside below 8 ft from north to south through early Mon, just as another dissipating cold front approaching from the west delivers a new round of large NW swell. The reinforcing push of NW swell will cross most of the open offshore waters of Baja California and the Revillagigedo Islands to reach as far south as the coastal waters of Cabo Corrientes through mid week. Gulf of California: Light to gentle winds and slight seas will persist through the middle of the week, except for brief periods of southerly winds of 10 to 15 kt over the northern Gulf, influenced by the slow approach of weakening cold fronts today and again late Mon. Winds are forecast to briefly increase to 20-25 kt near the entrance of the Gulf of California by Mon evening, then near Cabo Corrientes by Mon night. Marine guidance indicates NW winds in the 15-20 kt range across the central and southern portions of the Gulf Wed night through Thu night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Strong NE to E winds will prevail across the Gulf region. The strongest winds and greatest areal coverage downstream of the Gulf of Papagayo will be each night as nocturnal drainage flow augments the winds. Seas are forecast to build to 8-10 ft by early Tue morning. Gulf of Panama: Moderate to fresh northerly winds will flow downstream to near 05N with pulse to 20 to 25 kt mainly in the southwest Gulf off the Azuero Peninsula. Accompanying seas will reach 6-8 ft. REMAINDER OF THE AREA... Strong winds and large, long-period NW swell accompany a cold front moving east across the north waters this morning between 130W and 140W. The strong winds are mainly associated with the cooler air delivered by the NW flow immediately following the front. These winds will diminish through late today as the front continues east and weakens. Recent altimeter satellite passes indicate 10 to 14 ft seas in the wake of the front, while a pair of ship observations indicate winds up to 30 kt behind the front. High pressure building in the wake of the front is supporting an area of fresh to strong trade winds farther south into the deep tropics, particularly from 06N-14N west of 130W. Farther to the southeast, recent altimeter satellite passes showed another older area of NW swell south of 10N between 100W and 115W with wave heights to 9 ft. This swell is expected to decay below 8 ft through today. Looking ahead, yet another cold front will follow on the heels of the first two front and traverse the northern waters Mon through Wed and generate continued pulses of strong W winds and swell in excess of 12 ft. This will erode the high pressure behind the current front, allowing trade wind flow to diminish accordingly. $$ GR