000 AXPZ20 KNHC 071001 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Feb 7 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 0900 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ axis extends from 01N100W to 01N110W to 03N124W. Scattered moderate convection is within 120 nm either side of its axis. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Latest scatterometer data indicate winds in the Gulf of Tehuantepec are 15 to 20 kt, with seas of 3-4 ft. The next Gulf of Tehuantepec gap wind event, with gale conditions possible, is expected late Thursday night as strong high pressure builds southward across the Gulf of Mexico in the wake of a cold front. High pressure of 1021 mb centered near 26N122W extends a ridge southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge, and weak troughing over the Gulf of California is supporting gentle to moderate northerly winds off the west coast of the Baja California peninsula. Seas in this area are in the 4-6 ft range. Light to gentle winds and seas 2 ft or less prevail over the Gulf of California, while moderate to locally fresh winds and seas 5-6 ft are off the southwest coast of Mexico, being the strongest winds about 90 nm of the coast of Mexico between Manzanillo and Cabo Corrientes. The high pressure is forecast to remain nearly stationary over the next 24 hours, but strengthen slightly. It is then forecast to lift northeast to near 32N119W by Wednesday afternoon. As this takes place, the pressure gradient between the associated ridging and the trough over the Gulf of California will tighten, thus allowing for fresh to strong NW-N winds to develop off the west coast of the Baja California peninsula Tuesday night and over the central part of the Gulf of California Wednesday morning through early morning Thursday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient between high pressure centered over the western Atlantic and low pressure over western Colombia and the SW Caribbean supports funneling of fresh to strong winds through the Gulf of Papagayo during the overnight and early morning hours, with the assistance of the nocturnal drainage flow. This weather pattern is forecast to persist most of the forecast period. On early Friday morning, broad high over the eastern United States extending a ridge southward across the Gulf of Mexico and the NW Caribbean will increase the pressure gradient across the region to support a longer fetch of fresh to strong winds over Papagayo with seas to 9 ft. This new gap wind event will be constant through Sunday morning. Northerly winds in the 15-20 kt range are expected across the Gulf of Panama and downstream to near 4N-5N through Wednesday. Winds are forecast to increase to 20-25 kt Friday morning associated with the aforementioned strong high pressure settling over the eastern United States. Otherwise, light and variable winds and 4-6 ft seas will prevail elsewhere. REMAINDER OF THE AREA... A ridge, associated with the 1021 mb center of high pressure west of Baja California continues to dominate the northern waters. Long period NW swell propagating through the northwest portion of the area is producing seas in the range of 8-14 ft range there. This swell train, with a leading edge period of 17 to 18 seconds, will reach the Revillagigedo Islands this morning, and near 100W on Wednesday. A relatively tight pressure gradient between the ridge mentioned above and lower pressures in the vicinity of the ITCZ is supporting a belt of moderate to fresh trades roughly between 05N-14N W of 117W. Scatterometer data confirmed the presence of these winds. Seas are in the 8-9 ft range based of altimeter passes. These marine conditions will gradually diminish in aerial coverage through Wednesday. The most recent scatterometer data and a couple of ship observations showed SW winds in the 20-30 kt range across the NW waters, mainly NW of a line from 30N133W to 27N140W. Seas are in the 9-14 ft range and are forecast to build to 16 ft Tuesday night. These marine conditions are the result of a series of deep low pressure centers with associated cold fronts, approaching the NW corner of the forecast area through Thursday. This will maintain a very tight pressure gradient across the NW part of the forecast region. One of these cold fronts will enter the forecast waters by Wednesday afternoon, reaching from 30N136W to 25N140W by Wednesday evening. At that time, expect fresh to strong winds on either side of the front with seas up to 18 ft in the wake of the front and near 30N140W. $$ NR