000 AXPZ20 KNHC 240907 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0900 UTC Tue Dec 24 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... Gulf of Tehuantepec Gale Warning: A tight pressure gradient between high pressure near the eastern slopes of Mexico's Sierra Madre Oriental and low pressure of the monsoon trough in the eastern N Pacific is supporting gale force northerly gap winds in and near the Gulf of Tehuantepec, with seas to near 15 ft. Marine interests should take necessary action to avoid hazardous marine conditions over the affected waters. The area of high pressure has started to weaken, and will continue to further weaken and shift eastward today. This will both veer winds over the SW Gulf of Mexico, and loosen the pressure gradient over the Tehuantepec region, helping to diminish winds below gale force in the Gulf of Tehuantepec today. Swell generated from these ongoing gap winds continues to produce a large plume of 8 ft or greater seas that extends beyond 100W. As winds diminish through the day, the areal coverage of seas 8 ft or greater will decrease. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N84W to 07N100W. The ITCZ continues from 07N100W to 09N126W to beyond 08N140W. Scattered moderate convection was noted from 08N to 10N between 134W and 138W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details about the ongoing gale force gap winds across the Gulf of Tehuantepec. A cold front is analyzed from northern Gulf of California, across California Norte to near 20N118W. The front will weaken as it continues to the southeast before stalling and dissipating from the central Gulf of California to through Baja California Sur by late today. The front has ushered in a set of NW swell, which will impact the open waters beyond 120 nm north of Cabo San Lazaro today and Wed. Farther south, the high pressure building in the wake of the front will support moderate to fresh northerly winds off Cabo Corrientes by late today, becoming strong by late Wed. Another cold front is forecast to move across Baja California Norte into the northern Gulf of California on Thu, bringing an an increase in winds and seas. A large set of NW swell will follow the front, with seas building to 12 to 16 ft N of Punta Eugenia, and to 8 to 14 ft between Cabo San Lazaro and Punta Eugenia by Thu night. This set of NW swell will build seas in excess of 8 ft seas over open waters reaching the Revillagigedo Islands by Fri, and lingering through Sat. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Seas generated by gales in the Tehuantepec region will continue to propagate across the offshore waters of Guatemala and El Salvador through today. Fresh to strong winds are expected across the Gulf of Papagayo and downwind to near 90W through the next several days. Elsewhere, gentle to moderate south to southwest monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador, while light to gentle flow will dominate across the Gulf of Panama. REMAINDER OF THE AREA... Low pressure has moved across the northern waters into the offshore waters of Baja California Norte. Winds west of this feature were reaching gale force N of the area Monday. This generated seas in excess of 12 ft, which has propagated into the northern forecast waters. Overnight altimeter passes depict seas reaching from 12 to 15 ft N of 25N and between 125W and 135W. Seas associated to this swell will slowly spread SE today while subsiding. A ridge extends from high pressure centered near 35N150W across the waters N of 20N. The pressure gradient between this ridge and lower pressure in the vicinity of the ITCZ is supporting fresh to strong trades N of the ITCZ to near 20N and W of 125W. Overnight altimeter passes depict seas reaching near 13 ft over this area in a combination of NW swell and shorter period NE wind waves. High pressure will continue over the waters N of 10N through the middle of the week before weakening. This will maintain this area of fresh to strong winds N of the ITCZ through Wed before diminishing. Looking ahead, the weakening high pressure over the northern waters will enable a cold front to move across the waters north of 25N and east of 125W from late Wed through Fri. The front will be followed by fresh to strong winds and building seas. $$ AL