000 AXPZ20 KNHC 272055 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2055 UTC Wed May 27 2020 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 2030 UTC. ...SPECIAL FEATURES... A Central American Gyre will develop in the eastern North Pacific by the end of the week. The gyre will move northward toward Central America and southern Mexico. This will advect abundant moisture into portions of Central America by the end of the week, through the weekend, and into next week. There is the potential for heavy rainfall over portions of Central America, especially from northern Costa Rica northward into southern Mexico. This will bring the potential for life-threatening flash floods and mudslides for the areas that receive the heaviest rainfall. Please refer to products issued by your local weather service for more information. Tropical cyclogenesis is possible in association with Central American Gyres. There is currently a low chance of tropical cyclone formation within the gyre over the next couple of days, and a high chance of tropical cyclone formation within the next five days. Please see the latest Tropical Weather Outlook for more information. ...TROPICAL WAVES... The axis of a tropical wave is along 89W north of 08N, moving west around 10 kt. Scattered moderate isolated strong convection is noted within 120 nm of the wave axis south of 11N. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 06N77W to 10N90W to 1010 mb low pressure near 12N103W to 08N137W. The ITCZ extends from 08N137W to beyond 08N140W. Numerous moderate isolated strong convection is noted N of 04N E of 87W. Scattered moderate isolated strong convection is occurring within 120 nm of the monsoon trough between 93W and 101W, between 104W and 109W, and between 121W and 127W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please see the Special Features section for more details on the Central American Gyre expected to develop by the end of the week. A weak pressure pattern prevails across the area this afternoon, with light to gentle winds over much of the forecast waters. Some locally moderate NW winds are noted in recent scatterometer data near Los Cabos. Seas generally remain 4-6 ft offshore of Baja California, and 5-7 ft in SW swell over the waters south of Cabo Corrientes. Long-period S to SW swell will continue propagating across the southern offshore waters through the weekend. High pressure will build over the northern waters Fri night into the weekend, resulting in moderate to fresh NW winds off the coast of Baja California. Expect increasing winds and seas over the southern Mexico offshore waters this weekend in association with the Central American Gyre and possible tropical cyclone formation. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Please see the Special Features section for more details on the Central American Gyre expected to develop by the end of the week. The monsoon trough remains active offshore of Central America this afternoon, with numerous showers and thunderstorms N of 04N noted in satellite imagery and lightning data. Moderate to fresh SW flow prevails south of the monsoon trough, with 4 to 7 ft seas based on altimeter data from this morning. Note that gusty winds and locally rough seas are likely in and near thunderstorms. Expect increasing winds and seas over the offshore waters late this week and through the weekend, in association with the Central American Gyre and possible tropical cyclone formation. REMAINDER OF THE AREA... Stationary low pressure near 25N131W has weakened the typical high pressure ridge over the northern waters. Moderate to fresh winds and seas to 8 ft are likely found between this low and high pressure entered near 35N139W. Elsewhere, gentle to locally moderate winds are noted in recent scatterometer passes on either side of the monsoon trough/ITCZ. Weak low pressure analyzed along the monsoon trough near 12N103W is producing locally higher winds and seas, along with increased convection. A recent altimeter pass in this region shows 7-9 ft seas near the low, extending southward beyond the Equator where SW swell lingers over the southern waters. Low pressure near 25N131W will weaken by Fri, allowing a high pressure ridge to build across the northern waters. Southerly swell will decay across the far southern waters tonight, allowing wave heights to subside below 8 ft. $$ B Reinhart