000 AXPZ20 KNHC 251523 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1500 UTC Fri Nov 25 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Tropical Storm Otto at 25/1500 UTC is centered near 10.3N 88.2W, moving west or 265 degrees at 14 kt. Estimated minimum central pressure is 994 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Otto is forecast to continue to gradually weaken as the system moves westward through early next week. Please see the latest NHC advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. Gulf of Tehuantepec Gale Warning: The pressure gradient between high pressure over eastern Mexico and lower pressure in the vicinity of the ITCZ, as well as Tropical Storm Otto is supporting minimal gale force winds over the Gulf of Tehuantepec. Despite the high pressure weakening over eastern Mexico over then next couple of days, winds will still continue to increase to near 40 kt over the Gulf of Tehuantepec as the passage of Tropical Storm Otto south of the Gulf will help to tighten the pressure gradient. Seas will build to near 14 ft with the duration and extent of the gale force gap winds over the Gulf of Tehuantepec. Please see the latest High Seas Forecast product under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 09N93W to 07N100W to 08N108W to 09N120W to 11N128W. Scattered moderate to isolated strong convection is noted from 09N to 17N west of 120W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see above for more on the Gulf of Tehuantepec gale force gap wind event. Outside of the Gulf of Tehuantepec, high pressure over the Great Basin region of the United States combined with elongated inverted surface troughing over northwest Mexico is supporting fresh to strong northerly winds over the northern and central Gulf of California, with seas reaching 8 ft north of 29N. The area of high pressure will weaken today which will help diminish winds over the Gulf of California below advisory criteria. 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 cold front passage. A set of long period NW swell is propagating across the offshore waters of the west coast of the Baja California Peninsula with combined seas of 8-12 ft as depicted by a recent altimeter pass. This swell event will reach the Revillagigedo Islands by Friday afternoon with seas of 8 ft covering the waters W of 112W. Additional pulses of NW swell will continue to affect the offshore forecast waters during the upcoming weekend. A strong cold front will move toward Baja California Norte Sunday night into early Monday bringing fresh to strong northwest winds behind it with seas building to 10 to 14 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the special features section above for details on Tropical Cyclone Otto. Elsewhere, light to moderate northwest to north flow and combined seas of 3 to 5 ft prevail north of 10N, with moderate to locally fresh southwest flow and combined seas of 3 to 5 ft south of 10N. Little change is forecast through the upcoming weekend and into early next week outside of the influence of Otto. REMAINDER OF THE AREA... High pressure of 1031 mb centered west-northwest of the area near 34N159W extends a ridge across the northern waters. The pressure gradient between the ridge and lower pressure in the vicinity of the ITCZ continues to support a large area of 20 to 30 kt trades across the west- central waters. Seas over this area are in the 8 to 12 ft range in a mix of northwest swell and northeast wind waves. Little change in marine conditions are expected through the upcoming weekend. $$ Formosa