895 AXPZ20 KNHC 151544 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1605 UTC Wed Aug 15 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 1200 UTC surface analysis and satellite imagery through 1430 UTC. ...SPECIAL FEATURE... Tropical Storm Lane is centered near 10.7N 123.6W at 1500 UTC, moving W at 12 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained winds area 35 kt with gusts to 45 kt. The surface circulation of the tropical storm is very small with 25 kt winds occurring within 60 nm of the center. Scattered moderate to strong convection is observed in bands within 120 nm of the center, while scattered moderate isolated strong convection is seen from 180 to 360 nm across the W semicircle. The tropical storm is expected to continue moving westward through Fri while steadily intensifying, reaching hurricane strength Thu night as it reaches warmer waters and more favorable atmospheric conditions. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP4/WTPZ24 KNHC for more details. ...TROPICAL WAVES... No tropical waves are currently present. A tropical wave previously indicated to be transiting over Central America has been absorbed into a tropical wave to its east over the Caribbean Sea. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends across Panama and Costa Rica and enters the Pacific Ocean near 09N84W to 11N114W. Widely scattered to scattered moderate to strong convection is noted within 240 nm either side of the trough E of 110W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Weak ridging persists across the waters west of Baja California, supporting gentle to moderate NW wind flow and 4 to 5 ft seas in the adjacent offshore waters. Little change in this wind pattern is expected through Fri, before the trough dissipates and allows the pres gradient to tighten modestly leading to freshening NW winds. Long period southerly swell will spread into the regional waters this afternoon through Fri to raise seas to 6-8 ft. Gentle to moderate SE breezes continue across the Gulf of California, although brief pulses of moderate to fresh W to SW winds possible over the far northern Gulf today, and again nightly throughout the week. The approaching southerly swell will move into the southern waters this afternoon through Fri to raise seas to 4-7 ft. Farther south, strong cross equatorial S to SW swell will move into the offshore waters between Puerto Angel and Baja California Sur today, with seas peaking at 7 to 10 ft tonight into Thu morning, and highest seas across the waters between Guatemala and Manzanillo. This will produce very large and dangerous surf conditions along the coastlines and outer reefs with localized breaking waves building to 15-20 ft today through Thu morning. Looking ahead, fresh to briefly strong northerly gap winds are expected Thu night and Fri night across the Gulf of Tehuantepec. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh gaps winds are expected during the overnight hours through mid week followed by fresh nocturnal easterly flow through Fri morning. Gentle to occasionally moderate E winds are forecast elsewhere N of the monsoon trough which will meander between 09N and 11N. Moderate to locally fresh southerly winds are forecast S of the monsoon trough through early next week. Long period S to SW swell have spread into the regional waters and raised offshore seas to 6 to 8 ft on either side of the Galapagos Islands. A stronger and larger pulse of SW swell will move into the regional waters today and will raise seas to 7-10 ft by midday through early Thu before slowly subsiding through Fri. This swell will produce large and dangerous surf conditions along the coasts and outer reefs of the region. REMAINDER OF THE AREA... Weak 1011 mb low pressure is centered near 17N136W. Scattered moderate continues within 120 nm of the center in the northern semicircle. Fresh easterly winds are still occurring across the northern periphery of the low center, with seas 7 to 9 ft. Building high pressure north of the area will maintain this area of fresh easterly winds today, even as the low pressure opens into a trough over the next couple of days, and reaches 140W tonight. Long-period cross-equatorial southerly swell, in the form of 7 to 10 ft seas, will propagate N across the tropical waters S of 20N E of 120W tonight through Thu, and then subside to less than 8 ft on Thu night. $$ Stripling/Landsea