000 AXPZ20 KNHC 120920 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0920 UTC Mon Aug 12 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 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Tropical Storm Henriette is centered near 19.5N 110.9W at 12/0900 UTC moving WNW at 12 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Scattered moderate convection is noted within 60 nm west semicircle. Little change in strength is forecast through tonight. Weakening is expected to begin by Tuesday, and Henriette is predicted to become a remnant low by Tuesday night. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4/WTPZ24 KNHC for more details. ...TROPICAL WAVES... A tropical wave with axis near 82W extends southward to 04N into the eastern Pacific. The wave is moving westward around 10-15 kt. Scattered moderate convection is noted north of 06N east of 82W. A tropical wave with axis near 101W is moving westward around 10-15 kt. Scattered moderate and isolated strong convection is noted from 12N to 16N within 180 nm of the wave axis. A tropical wave with axis near 122W/123W is moving westward around 10-15 kt. Scattered moderate and isolated strong convection is noted from 10N to 15N within 240 nm west and 120 nm east of the wave axis. Environmental conditions are forecast to become more conducive for tropical cyclone development during the next few days, and a tropical depression could form later this week while this system moves west-northwestward at 10 kt. Please see the latest eastern North Pacific Tropical Weather Outlook for more information. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N78W to 10N101W to 09N105W to 12N120W to 09N130W to 09N137W. The ITCZ extends from 09N137W to beyond 10N140W. Scattered moderate and isolated strong convection is occurring within 120 nm of the monsoon trough between 82W and 88W, and from 07N to 12N between 101W and 107W. Scattered moderate convection is noted within 180 nm north of the monsoon trough between 127W and 137W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features section above for more information about Tropical Storm Henriette. Moderate NW flow prevails over the Baja California offshore waters, with locally fresh winds occurring near and north of Punta Eugenia per recent scatterometer data. Little change in offshore winds and seas is expected through the week as high pressure remains west-northwest of the region. Fresh northerly winds will pulse across the Gulf of Tehuantepec through mid week as weak high pressure over the central Gulf of Mexico supports a modest pressure gradient across southern Mexico. Wind speeds will diminish by late week as the ridge weakens north of the region. Looking ahead, expect strengthening SE flow to develop over the northern Gulf of California by Fri as a low pressure trough deepens near Baja California. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Earlier scatterometer data showed fresh easterly winds funneling across the Gulf of Papagayo region. The pressure gradient across the western Caribbean Sea and Central America will continue to support fresh to occasionally strong NE to E winds pulsing across the Gulf of Papagayo through Wed night. Wave heights will build to around 9 ft downstream of the Gulf today as southerly swell mixes with NE wind waves. Wind speeds will diminish to moderate speeds by late week. The latest altimeter data suggests residual southerly swell over the southern waters is decaying as wave heights have subsided to 7-8 ft near the Galapagos Islands. 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 122W/123W. Moderate to fresh trade winds prevail from 12N to 23N and west of 130W according to the latest scatterometer data. Recent altimeter passes in this region indicate seas are running 7-9 ft within the fresh NE flow. Little change is expected over the next couple days as the pressure gradient persists between the monsoon trough and high pressure centered north of the region. Another area of fresh winds is noted south of the monsoon trough between 118W and 124W near an active tropical wave. Mixed SE and SW swell is maintaining 8-10 ft seas south of the equator, highest west of 115W according to the latest altimeter data. This swell will gradually decay over the next couple days, allowing wave heights to subside below 8 ft by Tue night. $$ Reinhart