000 AXPZ20 KNHC 301533 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1449 UTC Wed Aug 30 2017 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Fourteen-E is centered near 19.3N 108.6W at 30/1500 UTC or about 270 nm W of Manzanillo, Mexico or about 240 nm SSE of the southern tip of Baja California moving NNW at 8 kt. Estimated minimum pressure is 1003 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate and isolated strong convection is within 180 nm in the NW semicircle and within 270 nm off the coast of Mexico between 100W and 105W. This system is forecast to become a tropical cyclone during the next 12 hours while continuing to the NW toward Baja California Sur, gradually strengthening thereafter. Very large seas will propagate toward and up through the entrance to the Gulf of California creating hazardous conditions. Large and dangerous swells are likely to impact the coast of SW Mexico, and either sides of the Baja California Peninsula, with dangerous and life- threatening rainfall possible across nearby coastal locations. Please see the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4/WTPZ24 KNHC for more details. ..INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N86W to Potential Tropical Cyclone Fourteen-E near 19.3N108.6W to 13N120W to 10N140W. Scattered moderate convection is from 06N to 10N between 90W and 100W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Please refer to the special features section for information on Potential Tropical Cyclone Fourteen-E positioned SW of Mexico. A ridge axis extends toward the northern offshore waters just W of 120W supporting gentle to moderate NW flow across the open waters W of the Baja California Peninsula. Winds in the Gulf of California are currently light and variable with seas 2 ft or less, except 4 to 6 ft near the entrance. Conditions at the entrance to the Gulf of California, and over the southern portion of the Gulf will drastically begin to worsen as Potential Tropical Cyclone Fourteen-E approaches. In the Gulf of Tehuantepec, light offshore nocturnal flow is expected this week and the upcoming weekend, with light to gentle onshore flow during the day. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, gentle offshore nocturnal flow is expected through the remainder of the week, becoming gentle to moderate this weekend. Otherwise, light and variable flow is expected N of the monsoon trough, while moderate to locally fresh southerly winds are expected S of the monsoon trough. Long period southerly cross- equatorial swell, in the form of 5 to 7 ft seas will gradually subside through late this week. REMAINDER OF THE AREA... 1010 mb low pressure is centered along the monsoon trough near 11.5N132W. An altimeter satellite pass from 13 UTC indicated seas to 8 ft within 90 nm to the north of the center of the low, where trade winds are reaching 20 kt. A small cluster of thunderstorms is active in this area north of the low pressure as well. The low pressure area will weaken slightly as it continues west, moving west of 140W Sat. Farther north, northerly swell generated from strong winds off the coast of California will propagate into the discussion area south of 32N between 125W and 135W late today with combined seas to 8 ft, then decaying below 8 ft through Thu. Also, cross- equatorial southerly swell will breach the equator building seas to 7 to 9 ft south of the monsoon trough between 120W and 135W through the early part of the upcoming weekend. Otherwise, weak ridging dominating the waters W of 120W will support moderate to locally fresh trades and 4 to 7 ft seas through the remainder of the week and the upcoming weekend. $$ Christensen