917 AXPZ20 KNHC 150349 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ...SPECIAL FEATURE... A well defined low pressure center near 10.9N 121.2W 1008 MB AT 0300 UTC, has become better organized this evening, and the convective pattern currently supports an upgrading of this system to Tropical Depression Fourteen-E. The tropical depression is moving W at 12 kt, with maximum sustained winds to 30 kt occurring within 60 nm across the northern quadrant. Scattered moderate to strong convection is observed in bands within 180 nm across the NW quadrant, while scattered moderate isolated strong convection is seen from 90 to 330 nm across the SW quadrant. The depression is expected to continue moving westward through Thu while gradually strengthening to tropical storm force, before reaching warmer waters and more favorable atmospheric conditions Thu night into the weekend, when it is expected to move more northwestward and strengthen to hurricane force. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP4/WTPZ34 KNHC for more details. ...TROPICAL WAVES... A tropical wave is entering the basin along 80W-81W, moving westward near 15 kt. Scattered moderate to strong convection is occurring both east and west of the wave along the monsoon trough, from 05N to 12N east of 87W and across coastal portions of Panama and Colombia. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 09N72.5W TO 10N97W to Tropical Depression FOURTEEN-E near 10.9N 121.2W. Scattered moderate to strong convection is noted E of 97W, and within 180 nm S of the trough between 102W and 113W. ...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 for the next few days. 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 are possible over the far northern Gulf tonight into Wed, and again nightly through 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, cross equatorial S to SW swell will move into the offshore waters between Puerto Angel and Baja California Sur late tonight through Wed, with seas peaking at 7 to 10 ft Wed evening into Thu morning, and highest seas across the waters between Guatemala and Cabo Corrientes. This will produce very large and dangerous surf conditions along the coastlines and outer reefs with localized breaking waves 15-20 ft Wed 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 has spread into the regional waters today 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 overnight through Wed. This next pulse of cross equatorial swell will raise seas to 7-10 ft Wed through early Thu before slowly subsiding through Fri, and produce large and dangerous surf conditions along the coasts and outer reefs. REMAINDER OF THE AREA... Weak 1010 mb low pressure is centered near 17.5N133.5W, along a weakening tropical wave moving W-NW at 10 to 15 kt. Scattered moderate isolated strong convection has flared within 150 nm across the NW quadrant of the low. Fresh easterly winds are still occurring across the northern periphery of the low center, with seas 6 to 7 ft. Building high pressure north of the area will allow the area of fresh easterly winds to expand, and seas may build to around 8 ft, even as the low pressure opens into a trough over the next couple of days, reaching 140W by Wed night. Farther to the northwest, the remnant low of Kristy is centered near 25N140W, with an estimated pressure of 1014 mb. The low is weakening, and a recent scatterometer pass showed generally moderate winds north of the low pressure as it drifts west of the area. 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