000 AXPZ20 KNHC 272205 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2123 UTC Tue Sep 27 2016 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 FEATURES... Tropical Storm Roslyn is centered at 18.38 116.6W at 27/2100Z, or about 448 nm WSW of the southern tip of the Baja California Peninsula, moving northeast or 045 degrees at 8 kt. The estimated minimum central pressure is 1003 mb. Maximum sustained winds are 40 kt with gusts to 50 kt. Latest satellite imagery shows that Roslyn remains a sheared tropical cyclone with the low- level center removed to the southwest of the remaining convection due to moderate to southwesterly winds aloft. The imagery shows the remaining plume of scattered moderate to isolated strong convection between 60 nm and 150 nm of the center in the north quadrant. Scattered moderate convection is within 30 nm of a line from 20N113W to 22N113W. Roslyn is forecast to weaken to a tropical depression late tonight, then to a post- tropical remnant low by early Wed afternoon...then begin to track to the northwest later on Wednesday afternoon and through Thursday while dissipating. Refer to the latest NHC forecast/advisory under AWIPS/WMO headers WTPZ23 KNHC/TCMEP3, or visit the NHC website at http://hurricanes.gov for additional details. Tropical Storm Ulika is located in the far western edge of the discussion and high seas forecast area near 12.4N 140.0W at 27/2100Z, or about 986 nm ESE of Hilo Hawaii, moving northeast or 045 degrees at 4 kt. The estimated minimum central pressure is 997 mb. Maximum sustained winds are 50 kt with gusts to 60 kt. Latest satellite imagery shows that Ulika is becoming better organized during the afternoon with tightly coiled banding features around what appears to be an obscured eye feature. Scattered strong convection is within 60 nm of the center in the northern semicircle, and within 30 nm of the center in the southern semicircle. Scattered moderate convection is within 45 nm of a line from 13.5N133W to 15N135W to 15N138W. Refer to the latest NHC forecast/advisory under AWIPS/WMO headers WTPZ24KNHC/TCMEP4 , or visit the NHC website at http://hurricanes.gov for additional details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwest Panama at 10N84W to 11N92W to 11N100W to 11N105W to 12N112W. It resumes at 14N117W to 13N125W to 14N130W to 13.5N136W. Scattered moderate isolated strong convection is observed within 240 nm south of the axis between 90W and 93W. Scattered moderate convection is within 60 nm of the axis between 130W and 133W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A northwest to southeast oriented surface trough is analyzed from 11N96W to near Acapulco Mexico. Scattered moderate to isolated strong convection is noted from 09N to 16N between 98W and 103W. Relatively weak high pressure covers the area to the north of the tropical cyclones Rosyln and Ulika. The associated gradient is producing light to gentle N to NE winds to the west of the Baja Peninsula, with the exception of waters near and around the Rosyln. Pockets of diminishing showers and thunderstorms and strong E winds and combined seas of 7 to 11 ft will expand northeastward across the waters generally from 18N to 23N W of 114.5W through Wednesday night as Tropical Storm Roslyn continues northward while weakening. The subtropical ridge will extend from 29N120W to 20N106W on Fri with gentle N flow returning. The pressure gradient will tighten Fri. Moderate to fresh NW winds and 5 to 8 ft seas will prevail W of Baja Sat and Sun. Light to gentle NW winds are expected across the entire Gulf of California through Thu. Light and variable winds expected on Fri across the far northern gulf waters. Strong drainage flow will pulse across the Gulf of Tehuantepec during the late night and early morning hours from late Wed night to early Mon morning. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle S winds expected N of the monsoon trough, while gentle to locally moderate S to SW flow is expected to the south of of the monsoon trough through the upcoming weekend. Combined seas of 3 to 6 ft primarily in long-period SW swell are expected this week. REMAINDER OF THE AREA... A cold front moving SE out of the N central Pacific will weaken the subtropical ridge north of the region during the next couple of days. This will maintain gentle to moderate NE winds and 5 to 6 ft seas for the areas N of the monsoon trough not affected by Roslyn or Ulika. Moderate to occasionally fresh southerly flow and 6 to 7 ft seas will dominate south of the monsoon trough for at least the next couple of days. $$ AGUIRRE