957 AXPZ20 KNHC 021630 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1514 UTC Sun Sep 2 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 1515 UTC. ...SPECIAL FEATURES... Hurricane Norman is centered near 17.6N 129.1W AT 02/1500 UTC moving WNW or 285 degrees at 16 kt. Estimated minimum central pressure is 948 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Norman is moving toward the WNW near 18 mph (30 km/h), and this motion is expected to continue for the next couple of days with a gradual decrease in forward speed thereafter. Numerous moderate and scattered strong convection is seen within 90 nm SE and 60 nm NW semicircles of center. Scattered moderate and isolated strong convection is noted elsewhere within 150 nm of the center. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMEP1/WTPZ21 KNHC for more details. Tropical Storm Olivia is centered near 17.0N 112.4W at 02/1500 UTC, moving NW or 315 degrees at 6 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained wind speed remains 40 kt with gusts to 50 kt. A turn to the WNW is expected through Monday, followed by a turn toward the west late Monday or early Tuesday. Some strengthening is forecast, and Olivia could become a hurricane by Tuesday. Numerous moderate and scattered strong convection is found in the SW quadrant 210 nm. Scattered moderate and isolated strong convection is noted elsewhere from 12N to 17N between 110W and 117W. See latest NHC forecast/ advisory under AWIPS/WMO headers MIATCMEP2/WTPZ22 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends from 10N73W to 10N89W to 11N95W to 11N100W to 13N105W. No significant convection. Scattered moderate and isolated strong convection is present from 05N to 10N E of 87W and from 12N to 16N between 90W and 103W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A surface trough is forecast to remain over the the Gulf of California and the Baja California Peninsula through at least Tue as T.S. Olivia passes S of a weakness in the subtropical ridge. Based on this weather pattern, the tropical cyclone would pass closest to the offshore forecast waters on Mon. Tropical storm conditions could affect the waters W of the Revillagigedo Islands during this time frame. Recent scatterometer data indicates that the strongest winds associated with Olivia are all focused in the SE semicircle of this system. Swell generated by Olivia will propagate across the offshore forecast waters through Wed night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough will linger near 10N during the next few days. Winds on both sides of the trough axis will be gentle to moderate, and seas of 4 to 6 feet are expected through Monday night. REMAINDER OF THE AREA... See the Special Features section for details on Hurricane Norman and Tropical Storm Olivia. Tropical Storm Miriam is centered W of area but it is still producing an area of 8 to 10 ft seas W of a line from 30N137W to 27N134W to 23N137W. Otherwise, a ridge dominates the forecast waters N of 20N W of 120W. The pressure gradient between the ridge and hurricane Norman supports moderate to fresh N to NE winds across the waters N of 20N W of 120W with seas of 8 to 11 ft due to mixed swell generated by the above mentioned tropical cyclones. Winds are also increasing S of Hurricane Norman in a S to SW flow, particularly between 120W and 130W. An ASCAT pass confirmed the presence of these winds. Swell generated by tropical cyclones Miriam, Norman and Olivia will produce a large area of seas of 8 ft or greater for most of the waters N of 10N and W of 110W through Mon night. $$ CAM