000 AXPZ20 KNHC 112204 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Wed Apr 11 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 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough axis extends from 10N85W to weak low pressure near 08N86W 1011 mb to 06N94W to 05N101W, where the ITCZ begins and continues to 07N123W to 08N130W to 07N140W. A secondary ITCZ is just south of the discussion area extending from 04S89W to 03S100W to 03.4S104W. Scattered moderate isolated strong convection is noted within 210 nm south of the trough axis between 82W-85W, also within 180 nm north of the the first ITCZ between 124W-125W, and within 120 nm south of the same ITCZ axis between 106W-110W. Scattered moderate convection is within 180 nm north of the first ITCZ axis between 121W-125W, within 60 nm south of the same axis between 124W-127W and within 120 nm north of the secondary ITCZ between 98W-100W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh to strong winds are expected in the Gulf of Tehuantepec through Thu. Strong NW winds and large NW swell will move into the waters off Baja California Norte Thu. Strong NW-N winds are forecast to begin across the length of the Gulf of California Fri night into Sat. Strong gale force N-NE winds are possible in the Gulf of Tehuantepec beginning on Sunday, with possible maximum waveheights reaching to around 17 ft. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Light to gentle winds are expected during the forecast period. Seas in the 3 to 4 ft range will prevail, except south of 05N where southerly swell will maintain seas of 3 to 5 ft. Fresh NE-E gap winds are forecast to begin in the Gulf of Papagayo on Thu, diminish briefly Thu afternoon, then increase to back to fresh Fri. REMAINDER OF THE AREA... The pressure gradient between lower pressure in the vicinity of the ITCZ and a strong ridge of high pressure over the northern waters associated to a high pressure center of 1032 mb located well to the northwest of the discussion area is producing mainly gentle to moderate trades north of the ITCZ to about 22N, with the exception fresh trades to the west of 134W. The present high pressure ridging will continue to strengthen through Fri resulting in a tightening of the pressure gradient. This will bring an increase to the trades over this area as well as strong NW to N winds over the far northeastern part of the area, where they are forecast to increase to the strong range commencing early on Thu and expand to the south and west on Fri. NW swell will propagate southeastward during the next several days, with seas greater than 8 ft covering the waters north of a line from Baja California Norte to 08N140W by Thu. A second set of NW swell will move into the northern waters Thu night into Fri, bringing seas to near 13 ft over the waters north of 25N between 120W and 127W. Yet another NW swell will move into the NW waters Sat, with seas possibly reaching to near 14 ft over those same waters. Time lapse satellite imagery over a 24 hour period depicts that atmospheric moisture has been on the increasing trend over the tropics as weak generally low-level perturbations migrating westward are contributing to the available moisture. As a result, clusters of scattered showers and thunderstorms have developed over the tropics, to include that associated with the surface trough and ITCZ features as described above. $$ Aguirre