000 AXPZ20 KNHC 230939 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Tue Jun 23 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Low pressure of 1009 mb is centered near 12N116W. This low is the focal point of a broad area of an elongated area of low pressure that is located several hundred miles south- southwest of the southern tip of the Baja California peninsula. Latest satellite imagery shows diminishing convection of scattered moderate intensity roughly within 60 nm of 15N116W. Scattered moderate to isolated strong convection is seen from 10N to 12N between 112W-114W and also from 10N to 11N between 115W-117W. Gradual development of this system is possible and a tropical depression could form during the next couple of days while the disturbance moves westward. After that time, cooler waters are likely to inhibit further development. This system has a medium chance of tropical cyclone formation during the next 48 hours. An area of low pressure centered near 11N132W has a pressure of 1010 mb. It is also located more than 1500 miles southwest of the southern tip of the Baja California peninsula and continues to show signs of organization. Latest satellite imagery shows that deep convection associated with this system has decreased during the past several hours. Only scattered moderate convection remains within 30 nm of the points: 11N131W, 10N132W and 13N132W. The satellite imagery suggests the overall cloud pattern of this low is rather small. Environmental conditions appear conducive for gradual development of this system. This system is likely to become a tropical depression during the next few days while it moves generally westward. This system has a medium chance of tropical cyclone formation during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... The southern portion of a Caribbean Sea tropical wave is along 89W and north of 05N to across western El Salvador and eastern Guatemala. It is moving westward at about 20 kt. Only isolated showers and thunderstorms are noted within 120 nm east of the wave from 10N to 12N. A tropical wave with axis along 96W and north of 03N to across extreme west part of the Gulf of Tehuantepec region is moving westward at 10-15 kt. This wave is embedded in a very moist and unstable atmospheric environment. Over the last few hours numerous clusters of scattered moderate to strong convection have developed within 120 nm either side of the wave from 09N to 14N. Scattered moderate to isolated strong convection is seen from 08N to 11N between 98W-100W and also from 14N to 16N between 93W- 99W. Scattered moderate to isolated strong convection is also over some areas of southeastern Mexico. The shower and thunderstorm activity remain disorganized for the time being, however, environmental conditions are forecast to become favorable for development in a couple of days. This system is likely to become a depression by this weekend while it tracks in a west-northwestward motion parallel to the coast of Mexico. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwestern Colombia westward to across northern Panama and southern Costa Rica to the coast at 10N85W and lifts northwestward to 16N105W to low pres of 1009 mb near 12N116W and to 10N122W to low pres of 1010 mb and to beyond the area at 09N140W. Numerous moderate to isolated strong convection is noted from 02N to 09N east of 80W to the coast of Colombia. Scattered moderate to strong convection is within 120 nm south of the trough between 117W- 120W and also between 122W-125W. Scattered moderate convection is 30 nm of the trough between 137W-139W. OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The latest surface analysis reveals high pressure continuing over the offshore waters of Baja California, while a low pressure trough remains near the Baja peninsula and the Gulf of California. Overnight scatterometer data passes show gentle to moderate northerly winds over the Baja offshore waters, and recent altimeter data indicates seas remain 4-6 ft. Moderate to locally fresh northwest winds off the Baja peninsula will continue through Tue night, then diminish through late week as the offshore ridge weakens. Elsewhere, moderate southeast winds are over the central and southern Gulf of California, while moderate easterly winds continue off the southern coast of Mexico. The winds over the southern Gulf of California, including the entrance to the Gulf, will briefly become southwest to west at fresh speeds tonight and into early on Wed, then become gentle to moderate south to southwest winds through the end of the week. Looking ahead, the Special Features area of disorganized shower and thunderstorms that is located a few hundred miles south- southwest of the Gulf of Tehuantepec is likely to develop into a tropical depression by this weekend while it tracks west- northwestward parallel to the coast of Mexico. Another area of disturbed weather is forecast to form south of the Gulf of Tehuantepec by late this week. Environmental conditions are expected to be conducive for gradual development of this system over the weekend as it moves west-northwestward parallel to the coast of Mexico. Please see the NHC Tropical Weather Outlook for the latest updates. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... An overnight scatterometer data pass clearly showed moderate to fresh northeast to east gap winds over the Papagayo region. Elsewhere, gentle south to southwest winds are south of the monsoon trough, with light and variable winds north of the trough. Cross- equatorial southwest swell is allowing for wave heights of 5-7 ft between Ecuador and the Galapagos Islands, while combined seas elsewhere are generally 4-6 ft. Moderate to fresh northeast to east winds will pulse in the Papagayo Region through Thu, then significantly strengthen Thu night into Fri. Expect freshening monsoon flow Wed through late this week as broad low pressure develops offshore of southern Mexico. REMAINDER OF THE AREA... Please see the Special Features section above for more details on the potential for tropical cyclone development later this week. High pressure of 1025 mb centered just northwest of the area near 32N142W maintains a ridge axis across the waters north of 20N this afternoon. Moderate to fresh winds continue between this ridge and the monsoon trough, roughly from 12N to 20N west of 125W based on recent scatterometer data passes. Locally strong winds are noted near 1010 mb low pressure analyzed along the monsoon trough near 11N132W. Combined wave heights range from 6-8 ft within the area of fresh trades to 8-9 ft near the monsoon low. Elsewhere, moderate to locally fresh southerly flow continues south of the monsoon trough between 105W and 120W. Locally generated wind waves and southwest swell are maintaining wave heights to 8 ft in this region. Southerly swell dominates much of the waters south of 15N and east of 110W. This swell will gradually decay over the next couple days. Another set of cross- equatorial southerly swell may build seas over the southern waters late this week, along with strengthening monsoon flow as the possibility exists for two tropical systems to form offshore southern Mexico, one by this weekend, the other over the weekend. These systems will adversely impact marine conditions across the offshore waters off southern Mexico. Stay tuned to future marine forecasts that will have the latest details regarding winds and wave heights for these waters. $$ Aguirre