000 AXPZ20 KNHC 191006 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Dec 19 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 Storm Warning: Storm force northerly gap winds are blowing across the Tehuantepec region and will prevail through early this morning. However, gale conditions are expected to continue through the weekend and into early next week. Very large seas accompany these winds, ranging between 20 and 24 ft. Swell generated from this event will produce a large plume of 12 ft or greater seas that will extent to near 105W today. Marine interests transiting across or in the vicinity the Gulf of Tehuantepec over the next several days should be aware of this significant gap wind event, and take necessary action to avoid hazardous marine conditions over the affected waters. 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 08N83W to 06N91W to 06N97W. The ITCZ continues from 06N97W to 05N105W to 08N112W to 08N126W to 07N140W. Scattered moderate convection is within 120 nm either side of the ITCZ W of 105W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for details on the storm force gap wind event across the Gulf of Tehuantepec. Gulf of California: Strong high pressure just east of the Great Basin region support moderate to fresh NW winds across the Gulf of California, with seas to 4 ft. Winds and seas will increase to fresh to strong this evening as strong high pressure re- builds in the Great Basin area. These winds will prevail through Sat morning. A large set of long period NW swell, behind a dissipating cold front, will bring seas of 8 to 11 ft across the offshore waters W of Baja and N of Cabo San Lazaro today. This swell event will reach the Revillagigedo Islands Fri. Another set of NW swell is expected this weekend into early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Seas generated by a storm gap wind event in the Tehuantepec region will propagate across the offshore waters of Nicaragua through Fri night. The forecast calls for seas of 8 to 18 ft through tonight, and seas of 8 to 11 ft on Fri. Seas in northerly swell will build again to 13 ft on Sun as winds likely increase to near storm force in the Tehuantepec area. Fresh to strong winds are expected across the Gulf of Papagayo through early next week, with seas building to 11 ft. 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... A weakening cold front extends from 30N118W to 22N133W. The front is forecast to dissipate over the forecast waters today. A large set of long period NW swell will propagate across the northern forecast waters in the wake of the front. Seas of 8 ft or greater will dominate the waters W of 120W. High pressure behind the front is also bringing increasing trade winds across the west-central waters tonight through today, mainly from 10N to 20N W of 130W. Another set of long period NW swell is expected this weekend in association with a cold front approaching 30N140W by Fri morning. Fresh to strong winds are expected on either side of the front. The front will dissipate as it moves eastward during the weekend. High pressure will build in the wake of the front NW of 30N140W, helping to increase trades yet again across the west- central waters into early next week. $$ Ramos