000 AXPZ20 KNHC 030311 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0310 UTC Tue Dec 3 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 0300 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: Earlier scatterometer data from 1530-1600 UTC confirmed near gale to minimal gale force gap winds over the Gulf of Tehuantepec, while earlier altimeter data revealed seas to 12 ft well downstream of the Gulf. Gales are expected to continue through tonight with seas peaking around 15 ft. High pressure over the Gulf of Mexico will weaken on Tue, which will allow the local pressure gradient to relax and wind speeds to diminish below gale force by Tue morning. See latest NWS High Seas Forecast issued by National Hurricane Center under AWIPS/WMO headers HSFEP2/FZPN03 KNHC or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... A tropical wave axis is near 120W south of 16N, moving westward around 10 kt. Scattered moderate isolated strong convection is noted from 08N to 10N between 118W and 121W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 08N78W to 09N90W to 1011 mb low pressure near 07N103W to 10N120W to 1010 mb low pressure near 11N129W to 10N133W. The ITCZ extends from 10N133W to 10N140W. Scattered moderate convection is occurring within 180 nm north of the monsoon trough between 113W and 117W, and within 120 nm south of the ITCZ west of 137W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section above for information about the ongoing gale force gap wind event in the Gulf of Tehuantepec. Looking ahead, another gale force Tehuantepec gap wind event is possible Fri night through Sat. Fresh NW to N winds continue over the southern Gulf of California and across the entrance to the Gulf. Elsewhere, gentle to moderate northerly flow prevails over the Baja California Sur offshore waters southward to Cabo Corrientes. Light and variable winds prevail off the coast of southern Mexico, as well as offshore of Baja California Norte where a weak high pressure ridge is analyzed. Large NW swell is currently spreading across the Baja offshore waters, with 8-10 ft seas over the outer waters north of Cabo San Lazaro. Large NW swell will continue propagating SE across the Baja California Sur waters through Tue night, then decay on Wed as combined seas subside below 8 ft. A weak high pressure ridge will move eastward across the northern waters Tue and Tue night, briefly resulting in fresh northerly winds near Punta Eugenia. A weak cold front will pass over the northern waters Wed and Wed night. Fresh northerly flow will resume over the central and southern Gulf of California Thu night through Fri. The next set of large NW swell will move into the waters off Baja California late Fri night through Sat ahead of an approaching cold front. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong NE to E winds will pulse across and downstream from the Gulf of Papagayo through Sat. Moderate to locally fresh northerly winds will pulse across the Gulf of Panama through mid week, then diminish Thu into Fri. Elsewhere, gentle to moderate S to SW monsoon flow will persist across the offshore waters of Costa Rica, Panama, Colombia, and Ecuador during the next several days, along with weak S to SW swell. REMAINDER OF THE AREA... Large NW swell dominates the forecast waters north of 10N and west of 115W. Earlier altimeter data showed 8-14 ft seas across the northern waters north of 20N west of 125W, while peak seas at 00 UTC were analyzed to 13 ft. This swell will continue moving SE across the high seas while slowly subsiding through Wed night. A surface trough is analyzed from near 24N125W to 16N130W. Fresh E to SE winds are likely occurring east of the trough axis, and scattered moderate convection is noted within 90 nm of the trough north of 19N. This feature will slowly lift northward through Tue night, and associated winds will increase to strong speeds Tue as the pressure gradient tightens between this trough and a ridge over the offshore waters. This feature will weaken by early Wed. A developing cold front over the far NW portion will move eastward across the northern waters through Wed night. Another large set of NW swell will move into the NW waters late Thu and propagate SE through Sat, resulting in seas building to 12-18 ft over the NW portion on Fri. $$ Reinhart