000 AXPZ20 KNHC 040231 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC SAT JUN 04 2016 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 0300 UTC. ...SPECIAL FEATURE... A broad area of low pressure is analyzed along the monsoon trough near 10N117W with an estimated pressure of 1007 mb. Scattered moderate convection is noted within 120 nm in the northwest quadrant of the center. The system appears to be elongated from northeast to southwest with several cyclonic circulations currently noted. Easterly shear continues to impact this low. The low level center is slightly to the east of a more dominant mid level center. Atmospheric conditions remain favorable for gradual development, and there is a medium chance of tropical cyclone development over the next couple of days. Please refer to the Tropical Weather Outlook under AWIPS/WMO headers TWOEP/ABPZ20 for more details. ...TROPICAL WAVE... A tropical wave is moving west at 5 to 10 kt across Central America, reaching from off the Pacific coast of Costa Rica to Caribbean coast of Honduras. There is currently little enhancement of convection across the Pacific along the wave axis. The wave is expected to lose identity in larger scale circulation developing across the east Pacific. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from low pres near 12N101W 1007 mb to 13N110W to low pres near 10N117W to 07N120W to 08N135W. The ITCZ reaches from 08N135W to beyond 08N140W. Numerous moderate scattered strong convection is noted from 09N to 13N between 99W and 106W. Scattered moderate convection is noted within 120 nm nw quadrant of low pres near 10N117W. ...DISCUSSION... North of 15N, east of 120W: A weak surface ridge extending from a 1017 mb surface high pressure centered near 24N121W through the Revillagigedo Islands. This is maintaining light to gentle northwest breezes across the region. Wave heights are 3 to 5 ft. Little change is expected over the next couple of days. Looking ahead, a surface trough along the Gulf of California and northwest Mexico through early next week will deepen, allowing northerly flow off the central coast of the Baja California peninsula to increase to 15 to 20 kt. Seas will build to 5 to 7 ft accordingly. Showers and thunderstorms will increase early next week along the coasts of Guerrero and Oaxaca as a broad low pressure area forms over Central America. South of 15N, east of 110W: Moderate southwest flow converging into the monsoon trough is enhancing areas of showers and thunderstorms along the trough between 99W and 106W. This pattern will continue through the next couple of days. Looking ahead, the southwest flow will increase as broad low pressure forms over Central America. This will bring increased shower and thunderstorm activity to the area mainly north of 07N and east of 100W. There is high chance of heavy rainfall from Nicaragua to southern Mexico from Saturday into next week. Seas will build to 8 to 9 ft in this area as well late Sunday into Monday. Elsewhere from the equator to 32N east of 140W: A weak subtropical ridge north of 25N is allowing only light to moderate trade winds flow farther south into the tropics. There is enough convergence in the lower levels of the atmosphere to support scattered moderate convection along the ITCZ near 135W. The ridge will build over the next couple of days north of 20N, just as the low pressure area currently near 10N116W migrates west-northwest to the south of the ridge between 10N and 15N, crossing west of 120W by early Saturday. Much will depend the further development of this system. Looking ahead, a weak frontal boundary will cross east of 140W and north of 25N early next week, but with little impact on winds or seas. $$ Christensen