000 AXPZ20 KNHC 240840 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 840 UTC Thu Nov 24 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 0830 UTC. ...SPECIAL FEATURES... Hurricane Otto in the southwest Caribbean Sea near 11.2N 82.9W at 24/0900 UTC or about 74 nm north of Limon, Costa Rica and about 70 nm southeast of Bluefields, Nicaragua moving west at 7 kt. Maximum sustained wind speed is 75 kt with gusts to 90 kt. Estimated minimum central pressure is 981 mb. Associated deep convection is spreading from the southwest Caribbean Sea across inland portions of Nicaragua and Costa Rica, with very heavy rainfall increasing the likelihood of flash flooding and mudslides. The official forecast tracks Otto across Central America near the border of Costa Rica and Nicaragua through tonight, emerging into the Pacific Ocean near the Gulf of Papagayo by early Friday. Please see the latest NHC advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. Gulf of Tehuantepec Gale Warning: High pressure ridging is surging southward across eastern Mexico, tightening the pressure gradient across southeast Mexico. Northerly flow in the Gulf of Tehuantepec has increased to gale force as measured by recent scatterometer passes. Gale force winds are forecast to persist through Saturday night, with winds up to 40 kt expected Friday night into early Saturday. Seas will eventually build to 16 ft by Friday night. A very weak pressure pattern will then prevail Sunday through early next week with much more tranquil marine conditions expected for that time period. 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 axis extends from 10N84W to 06N101W. The intertropical convergence zone axis extends from 06N101W to 08N120W to 10N140W. No significant convection is present. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... High pressure across the U.S. Rocky Mountain region combined with elongated inverted surface troughing over northwest Mexico is supporting increasing northwest flow over the northern and central Gulf of California to fresh to strong in the next several hours. Winds will increase to up to 30 kt later tonight with seas building to around 8 ft. Some of these winds will manage to spill out west of Baja California Norte through passages. The gradient will then relax by Friday afternoon. A cold front will move across the area this weekend. Winds will increase to near gale force in the Gulf of California north of 29.5N Saturday night through early Sunday both ahead of and behind a pre-frontal trough, with winds diminishing by Sunday afternoon. Winds will increase again Sunday night into early Monday with the actual frontal passage, diminishing Monday afternoon. A tight pressure gradient is also present offshore of Point Conception, California, with fresh to strong northerly flow present. These winds are producing fresh northerly swell which is propagating into the area offshore of the west coast of the Baja California Peninsula. A set of northwest swell will also arrive by tonight building combined seas to 8 to 11 ft. Seas will then decay Friday through Saturday, with reinforcing northwest swell arriving for the remainder of the weekend into early next week. A strong cold front will move toward Baja California Norte Sunday night into early Monday bringing fresh to strong northwest winds behind it and large seas of 10 to 15 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... See the special features section above for details on approaching Tropical Cyclone Otto. Elsewhere, light to moderate northwest to north flow and combined seas of 3 to 5 ft prevail north of the monsoon trough, with moderate to locally fresh southwest flow and combined seas of 3 to 5 ft south of the monsoon trough. Little change is forecast through the upcoming weekend and into early next week outside of the influence of Otto, except for seas building slightly to 4 to 6 ft by early Saturday. REMAINDER OF THE AREA... A strong ridge extends across the waters north of the ITCZ. A surface trough is embedded in the ITCZ extending from 17N131W to 09N135W, with associated scattered moderate convection from 09N to 17N west of 128W. The pressure gradient between the trough and ridge continues to support 20 to 30 kt trades across the west- central waters. These winds combined with primarily northwest swell are producing seas of 8 to 12 ft. Little change in this pattern and marine conditions is expected through the upcoming weekend into early next week. $$ LEWITSKY