000 AXPZ20 KNHC 010254 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 101 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 0000 UTC surface analysis and satellite imagery through 0230 UTC. ...SPECIAL FEATURES... Tropical Storm Irwin is centered near 23.8N 128.3W at 01/0300 UTC or about 1010 nm W of the southern tip of Baja California moving NNW at 11 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate convection is present within 90 nm in the NE quadrant. Irwin is expected to maintain a NNW course during the next 24 hours and move over cooler waters. This will cause Irwin to lose convection and continue weakening. Irwin is expected to become a post-tropical cyclone within 24 hours. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP5/WTPZ25 for more details. ...TROPICAL WAVES... A tropical wave extends from 06N92W to low pres 1009 mb near 10N92W to 16N91W moving W around 20 kt. Scattered moderate and isolated strong convection is seen from 05N to 13N between 88W and 95W. Low pressure along the wave will help enhance winds and seas for the waters adjacent to Central America through Wed. A tropical wave extends from 05N98W to 17N97W moving W around 10 kt. Scattered moderate and isolated strong convection is found from 05N to 13N between 95W and 100W. A tropical wave extends from 07N109W to 20N109W moving W at 5 to 10 kt. No significant convection is associated with this wave. This wave may remain ill-defined during the next few days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N84W to low pres 1009 mb near 10N92W to 11N103W to 10N117W. The intertropical convergence zone axis continues from 10N117W to 07N130W, then continues as a northern extension from 18N128W to 10N140W. Scattered moderate and isolated strong convection is found from 05N to 08N between 85W and 88W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The narrow ridge extending SSE across the area between the remnant circulation of Hilary and Tropical Storm Irwin and the Baja Peninsula will weaken tonight and Tuesday and allow winds and seas to diminish. Generally light to gentle winds will persist elsewhere over the Gulf of California and the offshore Mexican waters south of 20N through mid week. Otherwise, lingering long period S swell from the Southern Hemisphere will maintain seas of 5 to 7 ft. Slowly developing low pressure associated with westward moving tropical waves is expected to bring fresh to strong winds and seas building above 8 ft to the waters between the Gulf of Tehuantepec and Cabo Corrientes Wed through Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh SW monsoonal flow S of 08N and cross- equatorial southerly swell are combining to produce combined seas of 7 to 9 ft across the waters. Seas will begin to slowly subside Tuesday through Wednesday as the S swell decay. A pair of tropical waves extending S from SE Mexico and from Guatemala are producing active convection along the coast of Central America from Costa Rica to Guatemala. These waves are expected to merge by mid week as then continue moving W. Fresh to strong E to SE winds will develop along and behind the easternmost wave across the waters of Guatemala and El Salvador on Tuesday as low pressure along the wave continues to develop. building seas to around 8 ft. REMAINDER OF THE AREA... Low pressure, the remnant of Hilary, is centered near 28N132W at 1012 mb. Fresh to strong winds and seas of 8 to 10 ft are occurring within 120 nm of the low. The low will dissipate during the next couple of days as it continues to the NW. High pressure centered off the NW Coast of the United States extends a narrow ridge through 32N126W parallel to the coast of Baja California to near 15N114W. The pressure gradient between the high pressure system and the area of low pressure associated with Hilary and Irwin will maintain moderate N to NE winds N of 20N and W of 130W tonight. Long period cross equatorial SSW swell continues arriving across the waters S of 08N and E of 110W. The swell will produce seas of 7 to 9 ft, which will persist until the swell decay around mid week. A weak pressure pattern will persist between the remnants of Hilary and Irwin and the equatorial trough to the S. This will result in a broadening area of gentle to moderate winds between 10N and 20N, W of 120W through the end of the week. $$ CAM