000 AXPZ20 KNHC 280255 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Jun 28 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... Newly upgraded Hurricane Alvin is centered near 17.4N 115.4W at 0300 UTC, or about 450 nm SSW of the southern tip of Baja California, moving NW at 14 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 65 kt with gusts to 80 kt. Scattered to numerous strong convection is within 45 nm of the center. The small central circulation of Alvin has become better organized this evening and strengthened to a hurricane. However, this is expected to be short lived as Alvin is expected to move NW and weaken very slowly through Friday morning, and then more weaken more significantly Friday afternoon through Saturday. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. Gulf of Tehuantepec Gale Warning: High pressure over the Gulf of Mexico combined with a tropical wave passing south of the Gulf region, and are causing a Gulf of Tehuantepec gap wind event. N to NE gale conditions are expected to start later tonight through Sat night before slowly diminishing Sun and Mon. Peak seas are expected to reach around 13 ft tonight and Fri. 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 details. ...TROPICAL WAVES... A tropical wave is analyzed north of 05N near 87W, moving W around 15 kt. No significant convection is associated with this wave. A tropical wave is analyzed north of 03N near 95W-96W, moving W around 15 kt. Scattered moderate to strong convection is from 04.5N to 09.5N between 90W and 101W, and from 04N to 13N between 101W and 107W. Computer model guidance suggests this wave will become better organized into the weekend and has potential to develop into a tropical cyclone to the west of 100W after 48 hours. A tropical wave is analyzed from 03N to 14N near 133W-134W, moving W around 15 kt. Scattered moderate and isolated strong convection is from 06N to 10N from 124W to 139W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10.5N75W TO 08.5N82W TO 09N107W TO 08.5N138W. The ITCZ is now west of 140W. Except for convection associated with tropical waves described above, little significant convection is occurring along the monsoon trough or ITCZ. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details about the Gulf of Tehuantepec Gale Warning. Quiescent conditions are expected for the next several days over the Gulf of California. Tropical Storm Alvin is expected to not significantly impact the Mexican offshore zone, with moderate to fresh NW to N winds west of Cabo Corrientes and Baja California through at least Mon night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... A tight north to south pressure gradient across Central America is causing a significant Gulf of Papagayo gap wind event. These fresh to strong NE winds are expected to extend from the coast to south of the Tehuantepec area along 09N through Sat before diminishing Sat night as the pressure gradient relaxes. The extended length of this plume of offshore winds extending from the Papagayo area will generate a broad zone of seas 7-10 ft through Sat that will combine with N swell from Tehuantepec to produce high seas between 90W and 100W through Sun. Moderate offshore winds will prevail north of the monsoon trough, with moderate S-SW winds south of the trough axis the next few days. New S to SW long-period swell will reach the equatorial zone beginning on Sun and produce rough waves. REMAINDER OF THE AREA... Please see the Special Features section for more details about Tropical Storm Alvin. A broad weak ridge extends from high pressure NNW of the area. Gentle to moderate trades prevail south of the ridge. Seas are mainly 5-8 ft in mixed northerly and southerly swell. Overall high pressure will continue for several more days. Trades will strengthen slightly in the W central waters this weekend into early next week, with seas building to 8-10 ft, and SE swell along the equator will gradually decay. $$ Stripling