000 AXPZ20 KNHC 112053 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2017 UTC Thu Apr 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Gulf of California Gale Warning: Fresh to strong NW winds prevailing over the central and southern Gulf of California as strong high pressure builds into the region from the northwest will diminish later this evening. SW to W gap winds are expected to strengthen to gale force tonight over the northern Gulf from 29.5N to 30.5N due to funneling through passages of the mountainous terrain of Baja California Norte. The duration and fetch of the gap winds will be sufficient to support seas to 8 ft by early Fri along 30N. Winds will quickly subside below gale force after sunrise Fri morning. Winds and seas will continue to diminish this weekend into early next week, becoming generally W to NW at 15 kt or less. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07N77W to 07N95W. The intertropical convergence zone continues from 07N95W to 08N115W to 04N140W. Scattered moderate showers and thunderstorms are active from 05N to 08N between 80W and 85W. Scattered showers and isolated thunderstorms are active from 08N to 10N between 105W and 135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Strong 1040 mb high pressure NW of the region maintains a broad ridge extending SE along the outer Baja California offshore waters to SE of the Revillagigedo Islands near 15N110W. Moderate to fresh NW winds prevail offshore of Baja California Norte along with large NW swell of 8 to 12 ft. The pressure gradient will tighten offshore of southern California and Baja California Norte as low pressure over the southwest United States deepens resulting in gale force winds near the Channel Islands. Outer fresh to strong winds will spread southward offshore of Baja California Norte tonight through Fri will support fresh NW swell off the coast of Baja California Norte through into Sat, with seas reaching 16 ft near Guadalupe Island by late Fri. Winds and seas will diminish and subside into Sun as the high pressure weakens and moves westward. More tranquil marine conditions are anticipated for the start of next week. Gulf of California: Please see the Special Features section above for information about the gale warning in effect for the northern Gulf of California tonight. Gulf of Tehuantepec: Gentle to moderate onshore winds will prevail across the Gulf of Tehuantepec region through Sun. Looking ahead, the next significant northerly gap wind event is expected Sun night into Mon as strong to near gale force N winds develop over the Gulf as a cold front moves by N of the area through the Gulf of Mexico. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Light to moderate, generally onshore winds will prevail across the Gulf and adjacent offshore waters through tonight before shifting offshore Fri through Sun night while extending downwind to 88W. Seas in the 4-6 ft range will gradually subside to 3-5 ft over the weekend. Fresh to strong NE to E winds are expected across the Gulf Mon and Mon night as high pressure builds N of the area. The increasing winds will build seas to 5-7 ft by Mon night. Gulf of Panama: Light to gentle breezes will prevail across the area through Mon. Seas will generally remain in the 4-6 ft range through Fri night in SW swell, then subside to 3-5 ft this weekend through early next week. Elsewhere, light to gentle winds will persist through the next several days. Wave heights between Ecuador and the Galapagos Islands will generally remain 5-7 ft through Fri in long period SW swell. Further offshore, seas will peak around 8 ft tonight through Fri night over the waters SW of the Galapagos Islands. REMAINDER OF THE AREA... A strong high pressure ridge extends across the northern waters from 1040 mb high pressure centered NW of the region near 36N141W. Earlier scatterometer data showed a broad area of fresh to near gale force trades from generally N of 15N and W of 110W. Peak seas of 10-16 ft prevail in mixed NE wind waves and long period NW swell as indicated by recent altimeter data. Elsewhere, fresh trade winds prevail S of 15N to near the ITCZ. This tight pressure gradient S and SE of the ridge will persist through the end of the week, before the ridge begins to weaken slightly and drift W into the weekend. Seas will remain 12 ft or greater W of 125W into Fri, with seas of 8 ft or greater currently extending to 110W finally subsiding through early next week. Elsewhere, earlier altimeter data showed a region of 7-9 ft seas S of 11N between 95W and 120W in merging SW and NW swell. These seas will subside through the next several days, except S of the equator where reinforcing southerly swell will help to keep heights in the 7-9 ft range. Much more tranquil marine conditions are anticipated for early next week. $$ Christensen/Lewitsky