000 AXPZ20 KNHC 011446 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1446 UTC Tue Aug 1 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 1430 UTC. ...SPECIAL FEATURES... Tropical Depression Irwin is centered near 25.9N 129.2W at 01/1500 UTC or about 1069 nm WNW of the southern tip of Baja California, moving NNW at 9 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate convection is within 120 nm in the NE quadrant of Irwin. Irwin is expected to maintain a NNW course during the next 24 hours while weakening to a remnant low later today, and dissipating by 48 hours. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25 for more details. ...TROPICAL WAVES... A tropical wave extends from near the Gulf of Tehuantepec area at 15N95W to 1009 mb low pressure near 09.5N93W to 05N94W, moving W around 10 kt. Scattered moderate and isolated strong convection is within 300 nm in the SE quadrant, and also within 120 nm in the NW quadrant of the low. Associated winds are up to 20 to 25 kt in the NE semicircle supporting seas to 8 ft. These conditions will continue to shift W-NW offshore of Mexico during the next few days while the low and tropical wave parallel the coast. A tropical wave is N of 08N along 101W moving W at 10 to 15 kt. Scattered moderate and isolated strong convection is within 240 nm SW of the coast of Mexico between 94W and 104W, some of which is also associated with the tropical wave to the E as described above. A tropical wave is from 08N to 16N between 111W and 113W moving slowly W. Convection is limited at this time. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N74W to low pressure near 09.5N93W to 10N110W to 08N125W. The intertropical convergence zone axis extends from 08N125W to 10N140W. Scattered moderate convection is N of 10N E of 91W. Scattered moderate and isolated strong convection is within 120 nm either side of the axis between 114W and 124W, and also from 09N to 12N between 125W and 128W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A narrow ridge axis extends S-SE from high pressure well N of the area through 32N127W to 17N117W to the E of the remnant circulation of Hilary and Tropical Depression Irwin. The pressure gradient is weakening E of the ridge allowing for moderate to fresh winds offshore of Baja California to diminish with seas also subsiding as a result. Generally light to gentle winds will persist elsewhere over the offshore waters of Mexico, as well as in the Gulf of California. Long period southerly swells of 5 to 7 ft will gradually subside through the end of the week. An area of low pressure along a tropical wave near the Gulf of Tehuantepec area is forecast to continue to move W-NW and then more NW by the end of the week with associated winds and seas accompanying it, with the strongest winds and highest seas mainly on the NE side. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Low pressure along a tropical wave S-SW of Guatemala and El Salvador will trek NW of the area by tonight with associated fresh to strong winds and seas to 8 ft offshore exiting as well. Otherwise, long period southerly swells of 5 to 8 ft will gradually subside through the end of the week. REMAINDER OF THE AREA... Please see the special features section for information on Tropical Depression Irwin. The remnant low pressure area of Hilary is near 28N133.5W at 1012 mb. Winds on the N-NE side of the low have diminished to moderate to fresh and seas have subsiding to 6 to 7 ft. The low will dissipate through the day today, opening up into a trough by tonight. Otherwise, a narrow ridge of high pressure E of Irwin with gradually lose definition through the end of the week as high pressure builds into the NW portion of the area from N of the Hawaiian Islands. A weak pressure pattern will persist with mainly gentle to locally moderate trades through the forecast period. Meanwhile, seas will by generally 5 to 8 ft in mixed northerly and southerly swells. $$ Lewitsky