000 AXPZ20 KNHC 270233 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Thu Jun 27 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURES... Tropical Storm Alvin centered near 14.4N 111.3W at 27/0300 UTC moving W at 11 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Scattered moderate to strong convection is within 60 nm of the center. Scattered moderate convection is elsewhere between 90 nm and 210 nm in the NW quadrant. Some additional strengthening is forecast during the next 24 hours. Weakening is forecast to begin early Fri, and Alvin is expected to become a remnant low by Sat night. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. Gulf of Tehuantepec Gale Warning: Fresh to strong gap winds are expected to develop offshore in the Gulf of Tehuantepec, due to a locally tight pressure gradient combined with nocturnal offshore flow, Thu afternoon and then increase to gale force Thu evening. Winds are forecast to diminish below gale force Fri afternoon, then will pulse again Fri evening into early Sat. Peak seas will build to 12-13 ft downstream of the Gulf by Fri morning. Please read the latest High Seas Forecast issued by the National Hurricane Center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for further details. ...TROPICAL WAVES... A tropical wave is analyzed along 80W from Panama to 05N, moving W around 15 kt. Scattered moderate and isolated strong convection is N of 05N E of 80W. A tropical wave is analyzed along 90W from the El Salvador/ Guatemala border to 01N, moving W around 10 kt. Scattered moderate and isolated strong convection is N of 12N E of 90W. A tropical wave is analyzed along 126W-127W from 01N to 16N, moving W around 10 kt. Scattered moderate convection is from 06N to 08N between 126W and 128W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 09N79W to 08N88W to 09N109W. The ITCZ extends from 10N115W to 08N125W, then resumes from 08N130W to 08N140W. Scattered moderate and isolated strong convection is within 150 nm either side of the ITCZ W of 135W. Scattered moderate convection is from 04N to 06N between 121W and 124W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please read the Special Features section for more details about Tropical Storm Alvin which is located just SW of the offshores, and for more details about the developing Gulf of Tehuantepec Gale Warning. A broad and weak ridge axis extends from NW to SE across the offshores N of Cabo Corrientes. Mainly gentle to moderate winds prevail across the offshores per earlier scatterometer data. Seas are 4-7 ft outside of the influence of Alvin, except 3 ft or less in the Gulf of California. Little change is expected through Fri, with winds becoming NW and increasing to moderate to fresh offshore of Baja California this weekend through early next week as the ridging strengthens and builds eastward. As a result, seas will approach 8 ft by late this weekend into early next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate to fresh offshore winds in the Gulf of Papagayo will increase to fresh to strong by Thu morning as high pressure over Central America strengthens and with trades in the western Caribbean increasing. The fresh to strong winds will persist into early Sat, and will return Sun night through Mon. Seas will peak around 10-11 ft with the strongest winds. Otherwise, mainly moderate offshore winds will prevail N of the monsoon trough, with moderate S-SW winds S of the monsoon trough through the next several days. Seas will be mainly 4-7 ft, building to around 8 ft in SW swell across the Ecuador to Galapagos Islands offshore waters late this weekend into early next week. REMAINDER OF THE AREA... Please read the Special Features section for more details about Tropical Storm Alvin. A broad and weak ridge extends from 1024 mb high pressure just NW of the area near 34N142W to near 22N116W. Mainly gentle to moderate trades prevail, except locally fresh near the ITCZ. Seas are mainly 5-8 ft in mixed northerly and southerly swell, except 8-9 ft along the equator S of 110W due to SE swell. Weak low pressure may develop along a tropical wave across eastern portions this weekend into early next week with increasing winds and seas. Otherwise, the ridge will prevail through the next several days. Trades will strengthen slightly in the W central waters this weekend into early next week with seas building to 8-10 ft. Meanwhile, the SE swell along the equator will decay. $$ Lewitsky