120 AXPZ20 KNHC 011549 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Aug 01 2018 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 2145 UTC. ...SPECIAL FEATURE... Tropical Storm Hector centered near 13.8N 120.4W at 01/1500 UTC or 930 sm SW of the southern tip of the Baja California Peninsula moving W-NW at 11 kt. Estimated minimum central pressure is 1004 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Numerous strong convection is observed within 120 nm over the the Se semicircle of the center. Scattered moderate to strong is noted within 90 nm over the NW semicircle. Refer to the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP5/WTPZ35 KNHC for additional details. ...TROPICAL WAVES... A tropical wave is analyzed N of 06N along 83W and is estimated to be progressing W at 12 kt. Scattered moderate isolated strong convection is currently noted within 240 nm either side of the wave axis. A tropical wave extends from 07N106W to 17N106W and is moving W at 12 kt. Scattered moderate isolated strong convection surrounds the wave across the Pacific from 06N to 20N between 95W and 112W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the Caribbean coast of Colombia at 09N79W and extends W across Panama to the Pacific coast of Costa Rica at 09N83W, then turns SW to 09N90W, then turns NW 15N111W where the trough loses identity in the cyclonic circulation associated with Hector. Scatterometer winds indicates the monsoon trough resumes SW of Hector near 12N123W and extends SW to beyond 09N140W. Scattered moderate isolated strong convection is observed within 210 nm either side of a line from 06N78W to 12N95W, from 06N to 20N between 95W and 112W, and elsewhere within 240 nm either side of a line from 15N116W to 11N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Gulf of Tehuantepec: Gentle onshore flow is expected during the daylight hours becoming moderate to fresh offshore flow during the overnight hours. Wind are forecast to increase to 20-30 kt across and 120 nm downstream of the Gulf of Tehuantepec during the upcoming weekend as the pressure gradient strengthens across SE Mexico. Gulf of California: Gentle to moderate southerly winds are expected along 30N with light to gentle southerly flow expected elsewhere through the upcoming weekend. A surface low is forecast to develop near 09N102W on Thu and move NW to near 11N102W on Fri then turn to the N and track across the far offshore waters between 100W and 110W during the upcoming weekend and into early next week. Although track and intensity are uncertain, mariners should expect increasing southerly and easterly winds and building seas. The low has a medium chance of developing into a tropical cyclone in 3 to 5 days. Otherwise, a broad N-NW to S-SE orientated trough will meander E to W across the Baja California Peninsula and the Gulf of California through the upcoming weekend. Gentle to locally moderate NW breezes are forecast W of 108W. Expect 3 to 5 ft seas throughout. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate easterly flow is expected through the upcoming weekend. Gentle to occasionally moderate E winds are forecast elsewhere N of the monsoon trough which is meandering between 08N and 10N. Moderate to locally fresh southerly winds are forecast S of the monsoon trough through the upcoming weekend accompanied by 4 to 6 ft seas. The exception is long period southerly swell, in the form of 7 to 9 ft seas, is forecast to reach along 3.4S E of 93W on Thu night and Fri. REMAINDER OF THE AREA... See the special features section for information on Tropical Storm Hector and the tropical waves section for details on the tropical waves. A surface low is forecast to develop near 09N102W on Thu and move NW to near 11N102W on Fri then turn to the N and later NW. This low has a medium chance of developing into a tropical cyclone in 3 to 5 days. Otherwise, a ridge will persist N of 20N W of 120W through the upcoming weekend, supporting moderate N to NE winds and 4 to 7 ft seas. Moderate to locally fresh southerly winds are forecast elsewhere S of the monsoon trough or roughly S of 10N for the next several days. $$ Nelson