938 AXPZ20 KNHC 072100 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1646 UTC Tue Aug 7 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 2100 UTC. ...SPECIAL FEATURES... Hurricane John centered near 18.7N 110.5W at 07/2100 UTC or 300 nm S of The Southern Tip Of Baja California moving NW at 9 kt. Estimated minimum central pressure is 969 mb. Maximum sustained wind speed is 90 kt with gusts to 110 kt. Numerous strong convection observed within 60 nm over the NE quadrant. Scattered moderate isolated strong convection noted elsewhere within 240 nm either side of a line from 23N110W to 14N106W. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP2/WTPZ32 KNHC for more details. Tropical Storm Kristy centered near 13.7N 127.1W at 07/2100 UTC or 1120 nm WSW of The Southern Tip Of Baja California moving W at 11 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Scattered moderate isolated strong convection is noted within 150 nm of 13N127W. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCPEP3/WTPZ33 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough stretches from 09N84W to 14N104W, then resumes from 12N131W to 15N140W. Scattered moderate and isolated strong convection is noted within 150 nm either side of a line from 06N78W to 12N105W and within 60 nm of 06N98W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... See the Special Features Paragraph above for details on Hurricane John. John is expected to affect the offshore waters between Manzanillo and Baja California Sur with winds and seas tonight through Friday night. Gulf of Tehuantepec: Strong nocturnal northerly drainage flow is expected over and up to about 120 nm downstream of the gulf waters through Wed night. High pressure ridging over the Gulf of mexico will weaken slightly Thu and Fri and allow the drainage flow to become moderate to fresh. Gulf of California: Fresh to locally strong southerly winds are expected n of 27N tonight. Large southerly swell will cause seas for the Gulf waters S of 26N to build to between 8 and 14 ft and S winds will increase to between 20 and 25 kt tonight through Wed night as Hurricane John heads NW and passes to the SW of Cabo San Lucas. Outside of the tropical cyclones, a weak pressure pattern will be in place through the end of this week due to the disruption of the typical ridging NW of the region by a large extratropical low pressure system centered to the W of California and Oregon. The weakened pressure gradient will generate gentle to moderate winds over the Pacific offshore waters beyond the influence of the tropical cyclones. The extratropical low is expected to weaken this weekend and allow the ridge to rebuild. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh to locally strong nocturnal NE to E flow is expected tonight followed by mostly fresh winds through the end of this week. Gentle to occasionally moderate E winds are forecast elsewhere N of the monsoon trough which is meandering between 07N and 11N. Moderate to locally fresh S to SW winds are forecast S of the monsoon trough through the end of this week. Seas of 4 to 6 ft will generally prevail, except for 6 to 7 ft seas for the waters near the Galapagos Islands. REMAINDER OF THE AREA... See the Special Features Paragraph above for details regarding Hurricane John and Tropical Storm Kristy which will affect the waters N of 10N during the next several days. Large swell greater than 8 ft will likely propagate at least several hundred miles away from Hurricane John through the end of this week, as it has becomes a very large system. The areas of 8 ft seas generated by swell from Hurricane John and Tropical Storm Kristy will merge on Thu. This large area of 8 ft seas will likely envelop most of the waters N of 15N and W of 110W through the remainder of this week. Ridging from 32N136W to 20N119W will retract NW during the next few days as John and Kristy affect the waters N of the monsoon trough. John will have the most effect on the ridge due to its large size. Strong NW winds west of the western United States will produce N swell that will cause seas to build to 8 ft or above for the discussion waters N of 29N between 120W and 124W tonight, before the swell subside. $$ CAM/MN