000 AXPZ20 KNHC 232146 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1954 UTC Wed Nov 23 2016 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 2145 UTC. ...SPECIAL FEATURES... Tropical Storm Otto in the southwest Caribbean Sea near 11.2N 81.3W at 23/2100 UTC or about 120 nm NE of Limon Costa Rica and about 165 nm ESE of Bluefields Nicaragua moving W at 6 kt. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Estimated minimum central pressure is 994 mb. Scattered moderate and isolated strong convection remains mainly across portions of the SW Caribbean Sea and eastern portions of Nicaragua, Costa Rica and northern Panama from 08N to 14N between 81W and 87W. The official forecast tracks Otto across Central America near the border of Costa Rica and Nicaragua by Thursday night into early Friday...emerging into the Pacific Ocean near the Gulf of Papagayo on Friday. Please see the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. Gulf of Tehuantepec Gale Warning: Fresh to strong northerly winds will develop this evening across the Gulf of Tehuantepec before reaching gale force by late tonight as the pressure gradient tightens due to the strengthening of the high pressure across eastern Mexico. This event is expected to persist through the next 48 hours with the strongest winds expected during the overnight and early morning hours, and seas building to up to 14 ft. Please see the latest High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The Monsoon Trough extends from 10N85W to 06N94W. ITCZ extends from 06N94W to 07N111W to 11N129W. Surface trough extends from 13N130W to 11N131W. ITCZ resumes from 11N133W to 10N140W. Scattered moderate convection is from 06N to 15N between 115W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure building across the U.S. Rockies will cause winds to increase to fresh to strong out of the N-NW across the Gulf of California north of 30N on Thursday, then gradually diminishing by Friday as the pressure gradient weakens. These winds are expected to seep through the northern passages of the peninsula into the Pacific waters west of the peninsula. Seas will build to up to 7 to 10 ft in the northern Gulf of California. Elsewhere, moderate to fresh northerly winds will persist west of the peninsula across the open Pacific waters. Northwest swell to the west of Baja California is decaying with combined seas of 5 to 8 ft...the highest to the S near the Revillagigedo Islands. A tight pressure gradient will setup offshore of southern California tonight into Thursday which will increase northerly winds to fresh to strong just to the north of the discussion area. These winds will send a fresh northerly swell of 7 to 9 ft into the area through this evening. Seas will continue to build to 8 to 12 ft Thursday through Friday as a new set of NW swell arrives behind a weakening frontal boundary. This swell will decay Friday into Friday night. A stronger cold front will approach from the NW on Saturday, moving across the area during the remainder of the weekend. Northwest swells will arrive with this front...building seas to 9 to 13 ft Sunday and Sunday night. Southwest winds in the northern Gulf of California will increase to fresh to strong Saturday night, shifting to the west-northwest by Sunday night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo...moderate drainage flow prevail across the area. Please refer to the Special Features section above for information on tropical cyclone Otto which is forecast to track across the region. Mariners planning to transit through the Panama Canal are also urged to monitor Otto...which is currently in the southwest Caribbean Sea. Elsewhere...gentle to moderate winds and combined seas of 3 to 5 ft prevail on either side of the Monsoon Trough. Little change is forecast through the end of the week and into the upcoming weekend. REMAINDER OF THE AREA... A decaying cold front is analyzed from 29N133W to 30N124W. A new set of northwesterly swell prevails behind the front with ranging between 8-13 ft. Strong ridging is punching across this boundary and extending across the waters north of the ITCZ from NW to SE. This ridge combined with a surface trough that extends from 13N130W to 09N131W is resulting in a tight pressure gradient across the west-central waters where fresh to strong trades prevail. These winds combined with decaying NW swell are producing combined seas of 8 to 11 ft. Little change in this pattern is expected through the remainder of the week and the upcoming weekend. $$ ERA