000 AXPZ20 KNHC 262158 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Jun 26 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. ...SPECIAL FEATURES... Tropical Storm Alvin centered near 14.3N 110.3W at 26/2100 UTC moving W at 12 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Scattered moderate to strong convection is within 60 nm of the center. Scattered moderate convection is elsewhere within 90 nm in the S semicircle, and also between 180 nm and 360 nm in the NE quadrant. Some additional strengthening is forecast during the next 24 hours. Weakening is forecast to begin on Fri, and Alvin is expected to become a remnant low on Sat. 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 78W from eastern Panama to 04N, moving W around 15 kt. Isolated moderate convection is within 30 nm of 06N79W. A tropical wave is analyzed along 88W-89W from El Salvador to 01N, moving W around 10 kt. Scattered showers are in the vicinity of the wave. A tropical wave is analyzed along 125W-126W S of 15N, moving W around 10 kt. Scattered moderate convection is from 05N to 08N between 120W and 127W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 07N78W to 06N90W to 11N105W. The ITCZ extends from 11N113W to 09N124W, then resumes from 09N130W to 09N140W. Scattered moderate convection is from 05N to 08N between 120W and 127W. Scattered moderate and isolated strong convection is from 05N to 11N between 134W and 140W. ...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 the latest scatterometer data, except locally fresh S of 20N and W of 100W due to outer convection associated with Alvin. 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 1022 mb high pressure just NW of the area near 33N141W 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