000 AXPZ20 KNHC 300243 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Fri Sep 30 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 0000 UTC surface analysis and satellite imagery through 0215 UTC. ...SPECIAL FEATURES... Tropical Storm Ulika is just west of the discussion area near 17.5N 140.7W 1006 mb, or about 810 nm east of Hilo Hawaii, at 0300 UTC moving NW or 305 DEG at 9 kt. The maximum sustained wind speed is 35 kt with gusts to 45 kt. Ulika remains under significant vertical westerly shear attributed to an upper trough that is just to its west. Abundant dry air aloft west of the trough is being entrained into the cyclone as observed in water vapor imagery. Latest satellite imagery shows diminishing scattered moderate convection well removed from the cyclone between 90 nm to 150 nm to its northeast. Minimal tropical storm winds are within 30 nm in the northeast quadrant, and 20 nm in the southeast quadrant of the cyclone. Ulika is forecast to weaken to a tropical depression on Friday as it continues to pull away from the area. Refer to the latest CPHC forecast/advisory under AWIPS/WMO headers WTPA22 PHFO/TCMCP2, or visit the CPHC website at http:www.prh.noaa.gov/cphc/ for additional details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwest Colombia to 10N85W to 11N96W to 13N106W. It resumes at 13N112W to 09N122W to weak low pressure at 13N134W 1011 mb. Scattered moderate convection is within 60 nm north of the axis between 95W and 97W, and within 120 nm south of the axis between 115W and 117W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Post-tropical remnant low of Roslyn is centered near 24.1N 115.6W 1014 mb moving N NW at 6 kt. Visible satellite imagery depicts the low as a cloud swirl consisting of mainly low clouds about 120 nm in diameter. Associated winds continue to diminish with only 20 to 25 kt with seas of 6 to 8 ft remaining within 30 nm of the low in the northeast quadrant of the low. The low is forecast to gradually dissipate through Friday afternoon. Otherwise, a sub-tropical northwest to southeast oriented ridge axis extends into the area from 32N136W to near 24N131W. High pressure covers the area north of 22N west of 123W. Light to gentle northerly winds are present west of the Baja California Peninsula with seas of 4 to 5 ft in mixed northwest and southwest swell. The ridge will strengthen and build southeastward through the next 48 hours. The associated gradient is expected to result in a moderate to fresh northwest flow. Seas will build to 6 to 8 ft over the far northern waters west of Baja California Norte on Saturday evening, and continue into Sunday. Light and variable winds are expected through the weekend across the northern Gulf of California, and light to gentle nw-n flow is expected elsewhere. Winds will increase through mid week as the ridge builds into the region. A high amplitude surface trough analyzed along 110W from 10N to 20N is forecast to drift westward over the next couple of days. Deep convection continues to be very active in an inverted-v shape pattern. The convection is of the scattered strong type intensity from 17N to 20N between the trough and 112W. Scattered moderate to isolated strong convection is noted from 17N to 20N east of the trough to 109W. Fresh to strong drainage flow will again occur through the Gulf of Tehuantepec in the overnight hours will again pulse up and down through the weekend, peaking to the range of 25 to 30 kt with seas of 8 TO 10 ft late at night and through daybreak. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle southerly winds are expected n of the monsoon trough, while gentle to locally moderate s to SW flow is expected s of the monsoon trough through the upcoming weekend. Combined seas of 4 to 7 ft, primarily in long-period SW swell is expected across the offshore waters through the upcoming weekend. REMAINDER OF THE AREA... The pressure gradient will tighten around the subtropical ridge over the next couple of days, with moderate to fresh anticyclonic winds expected between the monsoon trough/ITCZ and the ridge through Sunday, with combined seas around the range of 5 to 7 ft. $$ AGUIRRE