000 AXPZ20 KNHC 241001 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 737 UTC Tue Jan 24 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 extends from 05N109W to 06N113W to 04N134W to 05N140W. Scattered moderate convection is found from 08N and 10N between 138W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A cold front extends from 28N111W across the central Gulf of California to the Baja Peninsula at 26N111W. The front then continues as a weakening boundary to 21N112W. Large long period NW swell associated with the front will sweep east and southeast through Wednesday night, affecting waters primarily west of the Baja Peninsula with 8 to 16 ft seas, hazardous near-shore marine conditions and heavy dangerous surf along the coastline. The front will dissipate by this afternoon, with marine and surf conditions steadily improving during the next three days. 8 to 10 ft seas will persist west of 95W through Thursday. A surface trough induced by an upper-level trough extends from 14N110W to 21N107W. The trough is weakening the ridge in the vicinity of the mouth of the Gulf of California and Cabo Corrientes. The trough is expected to fill during the next couple of days. High pressure centered in the Bay of Campeche is producing a tight pressure gradient over southern Mexico. The gradient is supporting strong N to NE winds over the Gulf of Tehuantepec. The winds will become moderate this afternoon as the high moves east and the gradient relaxes. Model guidance suggests a classic setup for gales in the Gulf of California is in the making for Saturday and Saturday night. Models are in good agreement that winds draining southeastward through the Gulf of California during this time frame will reach 30 kt, but a local study suggests high pressure over the intermountain region of the United States will create a pressure gradient strong enough to generate near gale to gale force winds over most of the Gulf of California during this time frame. Winds during this event will probably reach gale force over the Gulf of California north of 29N. Winds will be fresh to strong over the Pacific waters to the west of Baja as gap winds bleed southwestward across the peninsula. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Fresh to strong gap winds will pulse through the Gulfs of Papagayo, Fonseca and Panama Tuesday night through the end of the week. Otherwise, light to gentle winds will prevail across most of the region through Tuesday. Seas will generally range between 3 and 5 ft until Tuesday, then build about a foot in response to arriving NW swell. REMAINDER OF THE AREA... A ridge anchored by 1029 mb high pressure centered near 31N145W extends east-southeast to near 21N114W. The ridge is building eastward behind a weakening cold front heading SE across Baja California Sur. The ridge supports fresh to strong trade winds north of the ITCZ from 07N to 20N west of 120W. Large NW swell continue to spread SE across most of forecast waters with 8 ft seas encompassing almost the entire basin outside the Gulf of California and west of 100W. Another smaller but still significant set of NW swell that was generated behind a cold front that will remain NW of the discussion area will reach the northwest part of the area Wednesday morning. The area of reinforcing NW swell will then spread southeastward through Thursday night. Seas will peak around 16 ft near 30N140W on Wednesday night. Forecast models remain in general agreement in developing an area of low pressure over the western waters near 10N137W on Thursday. As the low develops, a large accompanying area of fresh to strong winds will be possible from 12N to 26N W of 120W by Friday morning. The low is anticipated to begin weakening and turn toward the WNW on Friday and Friday night, The low will continue to weaken, which will allow the area of fresh to strong winds to vanish by Sunday morning. $$ cam