000 AXPZ20 KNHC 220952 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 945 UTC Tue Nov 22 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Tropical Storm Otto in the southwest Caribbean Sea near 10.7N 79.0W at 22/0900 UTC or about 191 nm southeast of San Andres, Island or about 291 nm east-southeast of Bluefields, Nicaragua, nearly stationary. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. The official forecast calls for Otto to move across Central America near or along the border of Costa Rica and Nicaragua by the end of the week as a minimal hurricane, then emerging offshore into the northeast Pacific Ocean as a remnant low. Interpolation of the official NHC forecast between days 3 and 5 still results in the possibility of tropical storm conditions in zone PMZ113 for Thursday night through Friday night. See latest NHC forecast/ advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. Gulf of Tehuantepec gale warning: Northerly winds are pulsing to fresh to near gale force with seas 8 to 11 ft early this morning, due to a locally tight pressure gradient. Winds are forecast to increase to minimal gale force Wednesday night as the gradient tightens due to strengthening high pressure ridging over eastern Mexico, with seas also building to 12 to 13 ft. Gales are then expected to persist through Saturday night, with the strongest winds, up to 40 kt, expected during the overnight and early morning hours Friday night into Saturday. Seas will build to up to 16 ft during the stronger winds. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N81W to 06N94W. The intertropical convergence zone axis extends from 06N94W to 10N115W to 09N124W to 10N135W to 08N140W. Scattered moderate and isolated strong convection is from 08N to 15N between 112W and 121W, and also from 08N to 16N between 126W and 134W. Scattered moderate convection is from 06N to 09N between 134W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weakening cold front has moved into northwest Mexico with northerly flow behind it in the Gulf of California, and west of the Baja California Peninsula. Model guidance continues to indicate winds increasing to fresh to strong out of the northwest in the Gulf of California west of 110W late Wednesday through Friday. These winds are expected to seep through northern passages on the peninsula into the waters west of the peninsula, and seas will build to 7 to 9 ft in the northern Gulf on Thursday and Thursday night. Winds will then diminish thereafter as the pressure gradient weakens. Otherwise, moderate to fresh northerly flow will persist west of the peninsula across the open Pacific waters. Northwest swells of 6 to 9 ft will decay through the day into tonight, while strengthening winds north of the area send fresh northerly swells into the waters building seas up to 7 to 10 ft Wednesday night, with seas building to 8 to 12 ft Thursday into Friday as a new set of northwest swell arrives. That swell will decay slightly Friday night into Saturday. A new cold front will approach from the northwest Saturday night and winds in the northern Gulf of California will increase to fresh to strong out of the southwest- west Saturday night. Seas will build once again this upcoming weekend with new northwest swell associated with the front arriving. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to strong offshore northeast winds will manage to build seas to 7 to 9 ft in the next several hours. The winds will diminish overnight tonight with seas subsiding. See the special features section above for potential impacts from tropical cyclone Otto later in the forecast period. Mariners planning to transit through the Panama Canal are also urged to monitor tropical cyclone Otto in the southwest Caribbean. Elsewhere, gentle to locally moderate offshore winds and combined seas of 3 to 6 ft prevail north of the monsoon trough, while moderate to fresh southwest flow and combined seas of 3 to 5 ft prevail south of the monsoon trough. Little change is forecast through the end of the week and into the upcoming weekend. REMAINDER OF THE AREA... Relatively strong high pressure ridging prevails across the northern waters while two surface troughs are embedded in the ITCZ to the south. The combination of these features is resulting in fresh to strong trades across the west-central waters, where northeast wind waves are mixing with long period northwest swell, producing combined seas of 7 to 11 ft. A decaying cold front will drop into the northwest corner tonight with a new set of northwest swell arriving. High pressure will be reinforced behind this weakening boundary, with the fresh to strong trades expected to persist through the remainder of the week and into the upcoming weekend. Another, and stronger cold front is forecast to drop into the northern waters Friday night into Saturday. Northerly winds behind the front will increase to fresh to strong with a new set of northwest-north swell arriving with the boundary. $$ LEWITSKY