000 AXPZ20 KNHC 092249 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Aug 09 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 2145 UTC. ...TROPICAL WAVES... A tropical wave with axis along 90W north of 05N is moving westward at 10-15 kt. Scattered showers and thunderstorms are within 60 nm west of the wave axis from 13N to 15N. Isolated showers and thunderstorms are elsewhere within 60 nm of wave axis. A tropical wave with axis along 96W from 05N to 17N is moving westward at about 10 kt. This wave remains embedded in a very moist environment per latest TPW satellite animation imagery, and is associated with a broad area of low pressure. Latest satellite imagery shows that deep convection associated with this wave has become concentrated to the north of 14N to just inland the coast of Mexico from Salina Cruz to near 98W. This convection is of the numerous moderate to strong type intensity. Scattered moderate to isolated strong convection is seen from 14N to 16N between 97W and 99W, and also from 11N to 14N between 97W and 101W. Locally heavy rainfall can be expected along portions of the southern and southwestern coast of Mexico during the weekend. An area of strong northeast to east winds along with wave heights reaching to 8 ft is within 60 nm west of the wave from 14N to 15N. These winds and wave heights are forecast to diminish late tonight, but may continue later on depending on future development of the wave and increased deep convection associated with it. This area of disturbed weather has a medium chance of tropical cyclone formation through the next five days. Please read the latest eastern North Pacific Ocean Tropical Weather Outlook for more information. A tropical wave with axis along 112W from 05N to 18N is moving westward at 10-15 kt. This wave is also embedded in a very moist atmospheric environment per latest TPW satellite animation imagery. Scattered showers and thunderstorms are within 120 nm either side of the wave axis from 10N to 16N. This wave is forecast to remain in a very moist and unstable environment during the next few days as it moves in a general westward motion. A tropical wave with axis along 126W from 04N to 17N is moving westward near 15 kt. No deep convection is present noted with this wave. Low pressure of 1011 mb is centered along the monsoon trough axis near 13N105W. Latest satellite imagery shows scattered moderate to strong convection within 120 nm of the low in the NW quadrant. Scattered moderate to isolated strong convection is within 60 nm of the low in the NE and SE quadrants. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1011 mb low over northern Colombia southwestward to 08N79W and continues northwestward from there to 13N91W to 14N97W to 13N101W to low pressure near 13N105W 1011 mb, then to 12N115W to 11N123W and to 10N129W, where latest scatterometer data indicates that it transitions to the ITCZ and continues to 09N134W and to beyond 10N140W. Aside from convection related to the 1011 mb low described above, scattered moderate to isolated strong convection is within 180 nm south of the monsoon trough between 79W and 82W. Scattered moderate convection is within 120 nm south of the monsoon trough between 116W and 123W, and within 60 nm south of the monsoon trough between 97W and 110W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough extends across the mid-section of the Baja California Peninsula this afternoon. The gradient between it and high pressure west of the Baja California Peninsula currently supports fresh to strong southeast to south winds over the northern part of the Gulf. As the gradients slackens some tonight, this will allow for these winds to diminish to fresh speeds and continue at moderate to fresh speeds through the weekend. Gentle to moderate northwest winds continue over the Baja California offshore waters, between the aforementioned trough and a 1021 mb high pressure center that is analyzed near 29N137W. This high pressure center will remain nearly stationary through early next week, with little change in offshore wind and sea conditions. Looking ahead, fresh northerly winds will pulse across the Gulf of Tehuantepec beginning on Sun and increase to fresh to strong speeds on Mon, with wave heights building to around 7 ft. Long- period southerly swell will continue to impact the southern waters, with another set expected to propagate through the region from Sat night through early next week. The wave heights for the combined seas will remain at less than 8 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The pressure gradient across the western Caribbean Sea and Central America will continue to support fresh to occasionally strong northeast to east winds pulsing across the Gulf of Papagayo through early next week, with resultant wave heights building to maximum of about 8 or 9 ft on Mon. Moderate southwest flow will persist south of the monsoon trough, elsewhere, with scattered showers and thunderstorms expected off the coast of Central America through the next few days. Recent and current satellite altimeter passes reveal wave heights reaching a peak of 8-9 ft between Ecuador and the Galapagos Islands. These wave heights will change little through the weekend, and then subside early next week. REMAINDER OF THE AREA... Please refer to the Tropical Waves section, for more information about regarding an area of disturbed weather near the and offshore the southern coast of Mexico. A surface ridge persists across the forecast waters north of 20N. Recent scatterometer data depicts gentle to moderate trades present between the ridge and the monsoon trough/ITCZ region. The scatterometer data also depicted moderate to fresh south to southwest winds south of the monsoon trough, roughly from 07N to 10N between 109W and 122W, where wave heights are reaching to near or at 8 ft as indicated by the latest satellite altimeter data pass across that area. Elsewhere, gentle to moderate winds southerly winds remain across the high seas domain. The latest satellite altimeter data pass revealed wave heights in the range of 8-10 ft south of a line from 02S120W to 01N108W to 01N98W to 02S91W and to 03.4S83W. As a rather significant southern hemispheric swell event continues, swell generated by this event will continue to cross the equator roughly between 83W and 131W through the weekend. This swell is forecast to propagate northward, reaching as far north as 11N between 110W and 122W. Mixed swell over the far western part of the area is south of 12N and west of 135W. This swell is forecast to reach northward to near 14N by Sun. The wave heights will begin to lower early next week as the southern hemispheric southerly swell energy slowly decays. $ Aguirre