000 AXPZ20 KNHC 270303 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Sun Dec 27 2020 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 0000 UTC surface analysis and satellite imagery through 0300 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 1008 mb low pressure near 07N88W to 07N110W to 06N120W. The ITCZ extends from 06N120W to 08N132W, and from 08N135W to beyond 06N140W. Scattered moderate to isolated strong convection is noted from 06N to 08N between 135W and 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehunatepec: Latest observations from Salina Cruz on the southern end of the Tehuantepec isthmus show 20 kt gap winds, hinting strong gap winds are still ongoing into the Gulf of Tehuantepec. This is down from the storm conditions a couple of days ago, but the pressure gradient between high pressure over the northeast Gulf of Mexico and lower pressure to the south in the tropics is still enough to support 20 to 25 kt winds through the early part of the week. Strongest winds will be overnight, due to an added component of drainage flow, supporting brief periods of seas to 10 ft. Seas are expected to reach 10 ft near the coast overnight, and again on Sun night. Looking ahead, building high pressure following a strong cold front in the Gulf of Mexico will support a new round gale force winds by Thu evening, with seas building to 18 ft Thu night. Gulf of California: Moderate NW winds and 2 to 4 ft seas prevail across the Gulf of California. Strong but highly localized W gap winds can be expected along 30N in the northern Gulf of California ahead of a cold front approaching from the west. Strong NW winds will follow Mon night over the far northern Gulf, with generally gentle breezes and slight seas elsewhere. Winds diminish over the northern Gulf Tue, but NW winds will increase to moderate to fresh over the central and southern Gulf through Tue and fresh to strong NW winds by Wed as high pressure builds west of the area. Elsewhere, moderate to fresh winds will prevail off the coast of Baja California Norte, with mainly gentle to moderate winds across the offshore waters of Baja California Sur. Large NW swell will propagate into the waters west of Baja California tonight through Sun night with seas building to 8-11 ft. Fresh to strong NW winds will accompany a cold front moving through the area Mon into Tue, with reinforcing NW swell building seas to 12 ft off Baja California Norte through mid week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, and WITHIN 750 NM OF ECUADOR... Fresh to strong NE-E winds will continue to pulse across the Papagayo region the next several days as high pressure remains in place over the western Caribbean. Winds may briefly reach near gale force close to the coast during the early mornings due to enhanced drainage flow. Swell generated from the Gulf of Tehuantepec gap wind event continues to affect the offshore waters of Guatemala and El Salvador, with seas up to 10 ft. Seas are expected to subside below 8 ft tonight. Otherwise, gentle to moderate winds will prevail on either side of the monsoon trough, except occasionally fresh near the Gulf of Panama. REMAINDER OF THE AREA... A frontal boundary is stalling and dissipating as it approaches Guadeloupe Island, followed by weak ridging north of 20N anchored by a 1026 mb high pressure area near 32N130W. Farther south into the deep tropics, a surface trough persists along the ITCZ between 07N to 11N between 130W and 135W. The pressure gradient between the area of high pressure and the surface trough is supporting fresh winds north and west of the trough. Moderate to fresh winds prevail elsewhere north of the ITCZ to near 20N and west of 120W. NW swell is propagating across the western waters, with seas 8 ft or greater west of 125W and north of 07N. A recent altimeter pass indicates seas peaking near 13 ft north of 25N and west of 130W. These large seas greater than 12 ft will slowly subside overnight. A new cold front approaching the area from the north central Pacific will move eastward across the waters north of 25N through Tue. This front will usher in a new set of NW swell, which will raise sea heights above 12 ft over the waters north of 25N and east of 135W Sun through Tue, diminishing into mid week. High pressure building in the wake of this front will support persistent fresh trades over the tropical waters from roughly 10N to 20N west of 120W Sun through mid week, with seas 8 to 11 ft in a mix of wind waves and NW swell. Farther east, a large area of lingering seas in excess of 8 ft generated from earlier storm force gap winds through the Gulf of Tehuantepec and strong gap winds pulsing in the Gulfs of Papagayo and Fonseca. Seas of 8 to 10 ft reach almost to the equator between 90W and 110W in a mix of swell. These seas should subside below 8 ft through late Sun. $$ Christensen