000 AXPZ20 KNHC 271557 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1454 UTC Tue Feb 27 2018 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 1500 UTC. ...SPECIAL FEATURE...The Fuego Volcano inland over Southern Guatemala near at 14.3N 90.9W is erupting. A plume of volcanic ash may reach to the surface across the Pacific waters N of 14N between 92W and 93W limiting surface visibilities. Mariners should exercise caution. If mariners encounter volcanic ash, they are encouraged to report the observation to the National Weather Service by calling 305-229-4425. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details on the ashfall advisory. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The ITCZ extends from 05N83W to 02N100W to 08N120W to 07N140W. A cluster of moderate to isolated strong convection is within 120 nm N of axis W of 137W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Pacific waters w of the Baja Peninsula: A ridge dominates the offshore waters and extends beyond the Revillagigedo Islands to near 18N117W. A series of weak cold fronts or troughs are forecast to sweep E across the northern offshore waters into the Gulf of California. One of this fronts currently extends from 30N117.5W to 26N128W, then continues as a dissipating front to near 28N136W. Fresh to strong winds and building seas in NW swell follow the front. Seas of 8-15 ft will dominate the waters N of 25N W of 116W tonight. This swell event will continue to propagate SE with seas in the 8-11 ft range affecting the waters N of 21N W of 113W by Wed evening. Gulf of Tehuantepec: Strong pulse of northerly winds was noted at sunrise. Moderate northerly drainage flow is forecast tonight. A gentle onshore flow then expected during the daylight hours with gentle offshore during the overnight hours through Thu. Model guidance is suggesting the next strong event will begin on Thu night and persist through sunrise on Sat with seas building to 10 ft downstream near 14.5N95W. Gulf of California: A strong SW breeze along 30N will continue ahead of a cold front that will drift E across the northern gulf waters through tonight, with strong NW winds forecast behind the front this evening. Fresh to locally strong NW flow forecast across the central waters on Wed with these strong conditions shifting S across the waters from 18N to 25N E of 111W, to include the southern approach to Gulf of California. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to locally strong NE winds will continue to pulse through and downstream of the Gulf of Papagayo this week, with seas building to 8 ft near 10.5N88W. Gulf of Panama: Fresh to locally strong northerly winds are expected tonight, then forecast to resume on Fri night. Elsewhere, gentle to moderate offshore flow will prevail N of 07.5N while light to gentle SW winds are forecast S of 07.5N. REMAINDER OF THE AREA... Strong high pressure of 1038 mb located NW of the area near 37N144W extends a ridge SE across the forecast waters to beyond the Revillagigedo Islands. The pressure gradient between the high and lower pressure in the vicinity of the ITCZ is supporting fresh to strong NE trades, and 8 to 13 ft seas primarily in NE swell, across the tropical waters N of the convergence zone and W of 115W. These marine conditions will persist over the next 48 hours. As previously mentioned, a cold front is moving across the N waters followed by fresh to strong NW-N winds and building seas of up to 15 ft in northerly swell. Model guidance indicates that the pressure gradient will relax some on Thu as the high pressure slightly weaken while moving westward, and a new cold front reaches the northern forecast waters. $$ GR