000 AXPZ20 KNHC 140329 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Feb 14 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: A tight pressure gradient between high pressure ridge of 1045 mb over eastern Mexico and the NW Gulf of Mexico and low pressure to the south of Mexico continues to produce northerly gales across the Gulf of Tehuantepec. The ridge has shifted slightly eastward this evening as forecast, and peak winds have diminished to around 35 kt, with max seas near 15 ft. The high pressure will continue to weaken and shift eastward through the next couple of days, the pressure gradient will respond by slackening, allowing for the gale-force winds to diminish to a strong breeze early Thu morning, and to gentle to moderate speeds Thu afternoon. Winds over the Gulf will become light and variable Thu evening. As winds diminish through the end of the week, the resultant seas will also subside, lowering to 8 to 11 ft early Thu and to 8 ft in mixed northeast and northwest swell by late Thu night. Please see the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03/HSFEP2, or at the website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details on this gale warnings. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 06N73W TO 03.5N78W TO 06N85W TO 05N90W. The ITCZ extends from 05N90W TO 01.5N115W to beyond 06.5N140W. Scattered moderate isolated strong convection is noted within 120 nm north of the ITCZ between 84W and 104W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the Special Features above for details on the ongoing gale force gap wind event in the Gulf of Tehuantepec. A weak high pressure of 1017 mb is centered to the southwest of the Baja California Peninsula near 24.5N115.5W. A weak pressure gradient over the offshore waters of Baja California is generally producing light to gentle winds, in anticyclonic fashion, with seas of 4 to 6 ft in northwest swell. A weakening cold front will move across the far northern waters west of Baja California Norte Thu night. The front will dissipate across central Baja and the Gulf of California on Fri. Moderate to fresh northwest to north winds will follow in behind the front, while gentle to moderate winds ahead of the front. Seas will build to near 16 ft to the west of Baja California Norte this weekend as strong northwest swell propagates into the area and northwest winds west of the Baja California increase to fresh to strong speeds. Elsewhere, light to gentle mainly northwest to north winds and seas in the 4 to 6 ft range will continue between the Gulf of Tehuantepec and Cabo Corrientes through Fri, then increase some on Sat mainly north of Manzanillo. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh winds over the Gulf of Papagayo will pulse to strong tonight and Thu night, then diminish to fresh Fri through Sun. Elsewhere a fresh breeze or weaker will prevail across the forecast waters through Mon. REMAINDER OF THE AREA... A strong cold front extends from a 994 mb low centered north of our area at 35N128W through 30N130W TO 23N136W TO 21N140W. Strong S to SW winds ahead of the front have shifted NE and are now N of 25N, while strong NW to N winds behind the front were occurring N of 29N. The front will progress eastward, reaching Baja California late Thu with the winds gradually diminishing. Late afternoon and evening altimeter data suggests peak seas of 17 ft, primarily in NW swell, along 30N across the northwestern corner of the area. 12 ft seas exist northwest of a line from 30N127W to 22N140W. With the wind forcing relaxing, the NW swell will progress southeastward, but gradually diminish. A more vigorous NW swell event will reach our NW corner Fri night with a large area of 12 ft seas, peaking at 16 ft on Sat. This swell event will spread over much of our area bringing at least 12 ft seas as far south as 10N through Mon. Total precipitable water imagery shows ample deep-layer moisture streaming northeastward from southeast of the Hawaiian Islands to the California coast and extreme Baja California Norte. The moisture is being advected by southwesterly flow located ahead of a rather extensive upper-level trough axis extending from the NW United States southwestward to just N of Hawaii. The upper level trough supports the deep low pressure system. Areas of elevated showers and thunderstorms with patchy light is embedded within these clouds, and expected to last through the end of the week, and gradually shift entirely inland across California. $$ Stripling