000 AXPZ20 KNHC 270347 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0345 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 13N between 91W and 92W 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... Scatterometer winds indicate an ITCZ develops at 05N86W and continues SW to 03N97W, then turns NW to 08N125W, then SW to beyond 07N140W. Isolated moderate to strong convection is observed within 30 nm either side of a line from 04N86W to 03N90W, and within 120 nm either side of a line from 14N118W to 10N132W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Pacific waters w of the Baja Peninsula: A NW to S ridge extends across the far offshore waters from 20N116W to 15N104W with a series of weak cold fronts or troughs forecast to sweep E across the waters N of the ridge this week. A moderate to fresh SW to NW wind shift will accompany a trough across the waters N of 27N early Tue followed by NW swell in the form of 8 to 14 ft across the waters N of 27N W of 116W on Tue night. Expect fresh NW winds and 8 to 12 ft seas N of 23.5N on Wed morning, and moderate N winds and 6 to 9 ft seas W of the entire Baja Peninsula on Wed night. Then expect the seas to subside to less than 8 ft briefly around Thu evening. Another cold front will reach 30N120W on Fri morning with another round of NW swell following the front driving seas back up to 8 to 12 ft N of 23N on Sat. Gulf of Tehuantepec: A brief strong pulse of northerly winds at sunrise on Tue will quickly diminish by late Tue morning. Moderate northerly drainage flow forecast on Tue night. 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 the next cold front drifting E across the northern gulf waters on Tue through Tue night, with strong NW winds forecast behind the front on Tue 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 24N 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 overnight and on Tue night, then resuming 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 well NW of the area is currently supporting mostly strong NE trades, and 8 to 12 ft seas, across the tropical waters N of the convergence zone and W of 120W. Model guidance indicates that the pressure gradient will begin to relax on Thu and continue to relax through the upcoming weekend. Around round of strong northerly winds across the waters N of 30N between 120W and 130W will diminish to a fresh N breeze late Tue, but expect 8 to 15 ft seas across the Pacific waters from 24N to 32N between 117W and 140W on Tue night, with the seas quickly subsiding on Wed and Thu, followed by another rough of large northerly seas on Thu night through the upcoming weekend. $$ Nelson