000 AXPZ20 KNHC 112233 AAA TWDEP Tropical Weather Discussion...Updated NWS National Hurricane Center Miami FL 2233 UTC Sun Aug 11 2019 Updated to add Special Features section 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 2200 UTC. ...SPECIAL FEATURES... A tropical wave with axis along 108W from 06N to 21N is moving westward at about 15 kt. A 1007 mb low is along the wave axis at 18N108W. During the past several hours, deep convection consisting of the scattered moderate to strong type intensity has increased within 60 nm northeast of the low pressure. Similar convection is seen from 15N to 17N between 109W and 113W. Scattered moderate to isolated convection is elsewhere from 16N to 19N between 107W and 110W and from 14N to 20N between 110W and 114W. The overall cloud pattern of this system is showing signs of becoming more symmetrical with time. In addition, scatterometer data from this afternoon highlighted strong winds near and to within about 60 nm to the east of the low center. These winds may be gusting to higher speeds in and near the deep convection. If current observed development trend continues, this system could strengthen to a tropical cyclone later this evening while it moves west-northwestward, away from the coast of Mexico. Thereafter, conditions are expected to become unfavorable for significant development as it will then encounter unfavorable environmental conditions. This system has a medium chance of becoming a tropical cyclone during the next 48 hours. Refer to the latest NHC Tropical Weather Outlook under AWIPS/WMO headers MIATWOEP/ABPZ20 KNC for more details. ...TROPICAL WAVES... A tropical wave with axis along 79W and north of 04N is moving westward at 10-15 kt. This wave is surrounding by a very moist and unstable atmospheric environment as indicated by both and conventional satellite imagery and in the latest TPW satellite animation. Scattered showers and thunderstorms are within 60 nm either side of the wave axis. Some of this activity appears to be weakening, however recent scattered strong convection has developed across most of Panama. A tropical wave with axis along 98W and from 05N to 17N is moving westward at 10-15 kt. This wave is also moving through a very moist and unstable atmospheric environment as depicted in latest TPW satellite animation. Scattered moderate to strong convection is within 180 nm east of the wave from 09N to 11N. A tropical wave with axis along 108W from 06N to 21N is moving westward at about 15 kt. A 1007 mb low is along the wave axis at 18N108W. This features are part of a broad area of low pressure that is embedded in a very deep moist and atmospheric environment. Scattered moderate to strong convection is observed moving west away from the low from 15N to 20N between 108W and 112W. Scattered moderate to isolated strong convection is within 120 nm west of the wave axis from 10N to 11N. Scattered moderate convection is within 60 nm east of the wave axis from 09N to 10N. Isolated showers and thunderstorms are elsewhere from 10N to 20N between 106W and 113W. Some development of this system is possible over the next day or so while it moves west-northwestward, away from the coast of Mexico. Thereafter, conditions are expected to become unfavorable for development as it will then encounter unfavorable environmental conditions. Please see the latest eastern North Pacific Tropical Weather Outlook for more information. A tropical wave with a northeast to southwest oriented axis extending from 06N121W to 14N119W and to 18N116W is moving westward at an estimated 24 hour speed of about 10 kt. The latest TPW satellite animation imagery indicates the wave remains embedded in a very moist environment. Scattered moderate to isolated strong strong convection is within 120 nm west of the wave axis from 10N to 11N. Scattered moderate convection is within within 120 nm either side of the wave axis from 11N to 18N. Environmental conditions are expected to become more conducive for tropical cyclone formation by the middle of this week as the system moves west-northwestward. This system retains a medium chance of becoming a tropical cyclone during the next 5 days. Please see the latest eastern North Pacific Tropical Weather Outlook for more information. A tropical wave with axis along 136W from 04N to 18N is moving westward at about 10 kt based on a 24 hour estimated speed. Scattered moderate to isolated strong convection is within 90 nm west of the wave axis from 08N to 10N. Scattered moderate convection is within 60 nm east of the wave axis from 08N to 10N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1009 mb low along the coast of northwestern Colombia near 10N75W westward to 10N86W to 10N99W and northwestward to 17N106W, then to 14N114W to 12N122W to 11N130W and to beyond the area at 10N140W. Aside from convection related to the tropical waves and the 1007 mb low pressure near 18N108W, scattered moderate to strong convection is within 60 nm south of the trough between 86W and 90W. Scattered moderate to isolated strong convection is within 120 nm south of the trough between 122W and 126W, also within 60 nm north of the trough between 87W and 90W and within 60 nm of the trough between 138W and 140W. Scattered moderate convection is within 60 nm south of the trough between 82W and 85W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A broad area of low pressure, as described above under Tropical Waves, remains off the southwestern coast of Mexico with mean center near 18N108W. Fresh winds are noted within the east semicircle, as well as along the Mexican coast near Manzanillo. This system is expected to move west-northwestward during the next couple of days, with a low chance of tropical cyclone formation. Moderate northwest winds continue offshore the Baja California Peninsula, with the exception of small pockets of fresh winds near Punta Eugenia based on the most recent scatterometer data. The high pressure ridge driving these winds will remain in place through the middle of this week, with little change in offshore winds and seas expected. Elsewhere, fresh north winds earlier noted across the Gulf of Tehuantepec have diminished to moderate winds this afternoon as weak high pressures remains centered over the south-central Gulf of Mexico. Northerly winds will pulse to fresh to strong speeds on Mon before diminishing to moderate speeds Mon afternoon. Wave heights are expected to peak to around 7 ft downwind from the Gulf of Tehuantepec. This pattern will repeat itself Tue, then pulse to mainly fresh speeds thereafter through Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The latest scatterometer data shows a narrow swath of fresh easterly winds near the Gulf of Papagayo. The pressure gradient across the western Caribbean Sea and Central America will continue supporting fresh to strong northeast to east winds pulsing across the Gulf of Papagayo through Tue night. Wave heights will build to between 8 and 9 ft each day in a mix of southerly swell and NE wind waves. Winds in this region will diminish to moderate speeds by mid week. Southerly swell is maintaining wave heights of 8 to 9 ft between Ecuador and the Galapagos Islands according to the latest altimeter data. The swell have begun to decay and wave heights will gradually subside to below 8 ft by Mon night. REMAINDER OF THE AREA... Please refer to the Tropical Waves section above for more information regarding potential tropical cyclone development this week associated with a tropical wave presently near 118W. Moderate trade winds prevail south of 25N and west of 120W, or between the monsoon trough and high pressure centered near 31N137W. These winds will persist during the next several days as the high remains nearly stationary. The scatterometer data pass from this afternoon indicated that the earlier small area of strong northeast winds that was north of the monsoon trough from 11N to 13N and W of 137W has diminished to mainly fresh speeds, with wave heights of 8-9 ft in mixed swell. Moderate to fresh southeast winds generally continue to the south of 10N and west of about 105W, with wave heights between 6-8 ft through Tue before subsiding to less than 8 ft. Mixed southeast and southwest swell is maintaining wave heights in the range of 8 to 10 ft to the south of the equator, with wave heights up to 8 ft seas reaching as far north as 11N between 104W and 115W. This swell will gradually decay through early next week, allowing wave heights in this area to subside below 8 ft by Tue night. $$ Aguirre