000 AXPZ20 KNHC 252151 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2017 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...SPECIAL FEATURES... Tropical Storm Otto is centered near 9.9N 89.3W or about ABOUT 225 nm...420 km S of San Salvador, El Salvador at 25/2100 UTC, moving west or 260 degrees at 14 kt. Estimated minimum central pressure is 996 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. The center of Otto is located on the eastern edge of the weakening convection due to increasing shear. Some gradual weakening is forecast during the next 48 hours and Otto is forecast to be a remnant low by Wednesday. 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 approaching Tropical Storm Otto is supporting minimal gale force winds over the Gulf of Tehuantepec. Winds are forecast to further increase to 40 kt tonight and continue through early Sunday. Seas will build to 15-16 ft with this gap wind event. 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 09N94W to 07N102W to 08N110W to 11N130W. a surface trough is embedded within the ITCZ and extends from 14N131W to 09N133W. Scattered moderate to isolated strong convection is noted on either side of the trough from 11N to 16N between 128W AND 134W. no significant convection elsewhere. ...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. These winds are forecast to diminish to 20 kt or less this evening as high pressure weakens. 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 has reached the Revillagigedo Islands 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 these marine conditions are expected through the next 48 hours. $$ GR