000 AXPZ20 KNHC 140949 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Sat Jan 14 2017 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 0930 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec gale warning: The combination of a tight pressure gradient over southeastern Mexico between strong high pressure over the Gulf of Mexico, and lower pressures south of Mexico, with the added assistance of local drainage effects is maintaining minimal gale force north to northeast winds through the Gulf of Tehuantepec. The 0406Z Ascat-B pass depicted a narrow swath of the gale winds through the mid-section of the Gulf. North to northeast winds of 20-30 kt are occurring within 120 nm of the Gulf. Resultant seas with this gap wind event are in the 9-12 ft range. The high pressure is forecast to weaken slightly by early this afternoon allowing for the gale winds to diminish to just below gale force. These winds increase back to minimal gale force this evening and continue into Sunday morning before diminishing on Sunday afternoon as the strong high pressure retreats eastward. Winds will then pulse to fresh to strong through Sunday evening, then diminish to moderate to fresh into Monday morning, to moderate Monday afternoon and become light northeast late Monday afternoon. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from 04N78W to low pressure near 03N81W 1011 MB to 02N85W. The intertropical convergence zone axis extends from 04N89W to 03N100W to 03N109W to 08N119W to low pressure near 07N125W 1011 mb to beyond 04N140W. Scattered moderate isolated strong convection is seen from 07N to 09N between 130W and 132W. Scattered moderate convection is within 60 nm south of the axis between 117W and 122W. Scattered moderate isolated strong convection north of the intertropical convergence zone axis is being enhanced by strong jet dynamics aloft at the base of an upper trough in combination with converging trade winds. This activity is present within 30 nm of a line from 13N111W to 15N113W, and also within 30 nm of 14.5N118W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the special features section for information on the Gulf of Tehuantepec gale warning. Elsewhere, a cold front extending from low pressure over southwest Arizona continues southwestward to over the northeast portion of the Gulf of California, then to 25N116W, and weakening to 20N124W. The cold front will quickly move across the southeast portion of Baja California Norte and the northern portion of the Gulf of California through this morning, then weaken as it moves across Baja California Sur and the southern Gulf of California through early Sunday. The segment of the front across the Gulf of California and Baja California Sur will reach near Cabo Corrientes to vicinity Socorro Island during Sunday morning as a dissipating boundary followed by a high pressure ridge axis that builds southeastward towards 20N108W. Fresh northerly winds will follow the front along with seas of 6-8 ft driven by a northwest swell that will spread southeastward through the waters west of Baja California through late tonight, then subside to 5-7 ft on Sunday as the swell energy decays. A large set of northwest swell will propagate southeastward into the waters off Baja California Norte Monday, with resultant combined waveheights reaching to the range of 7-9 ft before subsiding again to 4 to 6 ft by mid week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo and along the south coast of Nicaragua, fresh to strong northeast flow will continue to pulse through early next week. Seas will build to 8 to 10 ft during the strongest winds. In the Gulf of Panama, fresh to strong northerly winds will pulse through this morning, then diminish to fresh this afternoon. These winds then increase back to fresh to strong this evening, and through late tonight before diminishing to fresh again Sunday afternoon and to moderate to fresh Sunday evening and Monday. Seas will be in the range of 5-7 ft, and subside to 4-5 ft on Monday. REMAINDER OF THE AREA... Strong high pressure is building south-southeast in the wake of the above mentioned cold front. The combination of the high pressure and lower pressures to its south will lead to an increase of trade winds in the deep tropics west of about 120W tonight through early next week. Seas currently 8-10 ft in the trade wind area will build to 10 to 12 ft late Sunday, and into early on Monday in a combination of northeast trade winds and northwest swell moving into the area. Converging trade winds in the lower levels along with jet dynamics aloft at the base of an upper trough are enhancing scattered showers and a few thunderstorms along the ITCZ between 110W and 131W. Looking ahead, global models suggest that a large and very deep low pressure system will pass well to the north of the discussion area by the middle portion of next week. Northwest swell generated by this system is expected to arrive in the far northwest portion of the discussion area by early on Wednesday, with strong southwest winds just northwest of the area in advance of a cold front that may brush the far northern waters on Wednesday. $$ AGUIRRE