000 AXPZ20 KNHC 152145 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2048 UTC Mon Jul 15 2019 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 1800 UTC surface analysis and satellite imagery through 2100 UTC. ...TROPICAL WAVES... A tropical wave with axis along 89W from 04N to Honduras is moving westward at 15 kt. Visible satellite imagery continues to show a mid-level cyclonic circulation slightly ahead of wave axis. Convection has waned this afternoon, but scattered moderate convection is occurring from 05N to 15N between 86W and 92W. The 1800 UTC NHC Tropical Weather Outlook predicts that a low pressure will from in association with this wave by mid-week several hundred miles south of the southern coast of Mexico, and there is a chance this system could develop into a tropical cyclone late this week as it moves westward to west- northwestward. A tropical wave with axis along 99W from 02N to 17N appears to be weakening as it moves west at 10 to 15 kt. There remains some scattered convection within about 150 nm W of the wave axis from 06N to 10N. This wave is forecast to dissipate by mid-week. A tropical wave with axis along 108W from 02N to 17N is moving westward at 15 kt. Significant moisture and instability in the vicinity of this wave is leading to a broad area of numerous showers and thunderstorms with scattered strong convection from 06N to 15N between 103W and 112W. Gusty winds are likely occurringwith the stronger thunderstorms. A tropical wave with axis along 129W from 02N to 15N is producing scattered showers and thunderstorms with isolated strong convection within about 180 nm E of the axis from 06N to 11N. This wave is expected to continue moving west at 10 to 15 kt and enter the Central Pacific by late week. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1010 mb low along the northern coast of Colombia across Panama and southern Costa Rica to near 09N89W to 08N100W to 13N115W to 12N122W, where trade winds suggest it transitions to the ITCZ. The ITCZ then continues to 11N127W, where it is interrupted by the tropical wave with the axis near 129W. The ITCZ then re-forms at 08N131W and continues beyond 09N140W. In addition to areas of convection described above in the Tropical Waves section, scattered showers and thunderstorms are located within 120 nm of the monsoon trough between 80W and 82W and between 112W to 122W. Scattered moderate showers and thunderstorms are also occurring within 120 nm of the ITCZ between 122W and 127W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Several afternoon scatterometer passes showed light to gentle winds over most of the waters, due to a quite weak pressure pattern. Earlier altimeter imagery recorded waves heights for most areas of 5 to 7 ft from long-period southwest swell. This swell should gradually subside through the week. A trough over the Gulf of California will strengthen over the next few days as low pressure deepens over the southwestern United States. The result will be fresh to possibly strong southerly winds in the central and northern Gulf of California Tuesday into Wednesday. North and northwest swell being generated by gales off the west coast of the United States will propagate into waters west of Baja California Norte Tuesday into Wednesday, mixing with southwest swell and building wave heights to 8 to 9 ft. This swell should decay Thursday and Friday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gentle to moderate east to northeast winds are indicated by afternoon scatterometer data off Central America, north of the monsoon trough. Moderate to fresh south to southwest winds are occurring south of the trough, off Colombia and Ecuador. For waters near the Gulf of Papagayo, fresh to possibly strong easterly winds will pulse during the evenings through mid-week, leading to seas of around 8 ft. Long-period cross-equatorial southwest swell will continue to lead to seas of 5 to 7 feet across the waters, with wave heights south of the equator reaching 8 to 9 feet at times through the week. REMAINDER OF THE AREA... What was the remnant low of former Tropical Depression Four-E has now opened into a trough, with the axis stretching from 21N118W to 14N123W. ASCAT data from around 1800 UTC depicts moderate northwest winds to the northwest of this trough with seas of 4 to 6 feet according to an afternoon altimeter pass. Little convection is occurring with the trough, which is expected to weaken further as it drifts westward Tuesday, then dissipate Tuesday night. A nearly stationary high pressure is centered north of the forecast area at 33N140W, with a pressure of 1025 mb. A ridge axis extends southeastward to 30N135W just southwest of the southern tip of Baja California Sur. Moderate to fresh northeasterly trades are occurring southwest of the axis and north of the monsoon trough and ITCZ. Long-period southwest swell continues across much of the waters south of 20N. Altimeter passes this afternoon continue to show wave heights of 8 to 9 ft to the south of 18N and west of 110W. The swell will gradually decay through mid-week, allowing seas to gradually subside. $$ KONARIK