000 AXPZ20 KNHC 171608 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Fri Feb 17 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 1200 UTC surface analysis and satellite imagery through 1530 UTC. ...SPECIAL FEATURES... Gale Warning: A major Pacific storm system moving eastward toward the State of California has pushed a cold front across the local northwestern forecast waters this morning. This front is bringing gale force winds on both sides of the front, and very large seas behind the front and across the northwest waters. These hazardous marine conditions are expected to shift eastward across the north waters today and tonight. The southerly gale conditions and leading edge of large NW swell will reach the far offshore waters of PMZ009 and PMZ011 later today before diminishing below gale force tonight. The northwesterly gale conditions will just briefly reach the far offshore waters of these two zones early on Saturday morning before diminishing to strong to near gale force Saturday evening. Seas behind the front will peak around 27 ft this afternoon through tonight across the NW and N central waters then subside very slowly to near 20 ft across the NE waters Sat and Sat night. This large and dangerous swell event will reach the coast of Baja California Norte this evening and tonight, and spread southward across the whole Baja California peninsula Saturday, then reach the Cabo Corrientes region of Mexico early Sunday night. See statements from your local meteorological agency on this significant marine event for information on high seas, and associated dangerous beach and surf conditions. Gulf of California Gale Warning: Southerly winds will increase to 20-30 kt across the waters N of 30N today, and further increase to minimal gale force across the north waters by this evening, ahead of the approaching cold front mentioned above. The front will move east-southeast across the gulf waters tonight and Saturday. Minimal gale force southerly winds are possible over the gulf waters S of 28N on Saturday. Strong to gale force winds are also expected over the Baja California Peninsula mainly north of 28N late Friday and Friday night. Strong southerly winds, with frequent gusts to gale force are also expected to affect the States of Sonora and Sinaloa on Saturday. See statements from your local meteorological agency on this significant weather event expected to produce significant impacts across the EPAC waters, Baja California and NW Mexico. Refer to High Seas forecast under AWIPS/WMO headers MIAHSFEP2/ FZPN03 KNHC for additional details on these gale force wind conditions. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ and associated convection is located S of the area. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See Special Features section above for more information on the gale warning in the Gulf of California. Elsewhere, a weak pressure gradient prevails over the forecast waters. Light to gentle winds prevail off the coast of the Baja California peninsula with light and variable winds elsewhere. Seas are already in the 6-9 ft range off the coast of Baja California Norte in NW swell, and 5-6 ft elsewhere. A major pulse of NW swell with seas greater than 8 ft will spread southeast across all waters west of the Baja Peninsula by late tonight, and move into central portions of the Mexican mainland sun afternoon and evening. An approaching strong cold front with gale conditions, and very large NW swell in excess of 15 ft will impact much of the waters off the coast of Baja California through the weekend. Refer to Special Features section above for more information. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: moderate to locally fresh NE-E winds are expected early today with mainly gentle to moderate winds thereafter. Gulf of Panama: Moderate to fresh northerly flow is generally expected through Sat. Cross equatorial long period SW swell continues to affect the waters between Ecuador and the Galapagos Islands (except in the lee of the islands), with seas in the 5-6 ft range affecting the pacific coast of Central America. REMAINDER OF THE AREA... This strong cold front extended from 30N126W to 22.5N140W at 1200 UTC, and is supported by a vigorous upper level low and strong jet stream aloft. Global lightning data showed lighting activity in elevated convection N of 28.5N well ahead of the front and approaching coastal portions of southern California and Baja California Norte. Overnight ASCAT data indicated gale force winds have pushed into the forecast area west of the front. Gale conditions are forecast behind and ahead of the front as it shifts across the northern waters during the next 24- 36 hours. This front will also usher in a large NW swell event peaking near 27 ft late this afternoon through tonight. See the special features for more details. High pressure of 1018 mb centered near 21N113W will dissipate in about 24 hours as the above mentioned cold front moves eastward across the north waters. Northwesterly swells with seas greater than 8 ft are covering the area west of a line from 30N116W to 05N130W. This swell will spread southeastward while subsiding. $$ Stripling