000 AXPZ20 KNHC 170301 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0405 UTC Mon Apr 17 2017 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 0230 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The northern hemispheric ITCZ extends from 07N84W to 05N106W to 08N112W to 05N120W where it is interrupted by a surface trough that extends from 07N134W to 03N135W. Scattered/moderate isolated strong convection is within 120 nm south of the axis between 125W and 130W, and within 60 nm south of the axis between 90W and 101W. Scattered moderate convection is within 30 nm of the axis between 84W and 90W. A southern hemispheric ITCZ extends from 03.4S90W to 03.4S100W to 03S105W. Scattered moderate convection is within 30 nm of the axis between 90W and 93W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient along the west coast of the Baja California Peninsula has slackened as a cold front continues to weaken the ridge to the west of this region. Northwest to north winds across the waters west of Baja California are freshening, and will continue to do so through this evening. The ridge will remain nearly stationary through tonight before it begins to shift east northeast through Tuesday. The resulting tight gradient between it and toughing along Baja California will increase the fresh northwest winds to strong winds north of Punta Eugenia on Monday while fresh Northwest to north winds remain south of Punta Eugenia. The strong winds will spread southward offshore the northern and central sections of the Baja California Peninsula into Friday, then diminish on Friday evening. Seas of 5 to 7 ft offshore the Baja California Peninsula will subside slightly on Monday, then build again to 6 to 8 ft late on Tuesday as the northwest winds strengthen. Seas will build to between 8 and 10 ft by Thursday morning as a new pulse of northwest swell arrives. The pressure gradient between a strong high ridge dominating the Gulf of Mexico and lower pressures south of the Tehuantepec region continues to slacken. As a result, winds through the Gulf have diminished to mainly to moderate winds. Seas over the Gulf have lowered to 5 to 6 ft, and will continue to subside to around 4 to 5 ft on Monday as high pressure will shift eastward as low pressure develops over the southern plains today, allowing the pressure gradient to relax this afternoon. Fresh north winds this evening will generally become light and variable tonight through Tuesday. Seas will gradually subside to 4 to 5 ft by Tuesday as the aforementioned ridge shifts eastward while weakening. Light and variable winds and seas generally below 2 ft will prevail across all but southern portions of the Gulf of California through Monday night as the pressure gradient remains rather loose along the Baja California Peninsula. Seas of about 3 to 4 ft are expected near the entrance of the Gulf through Monday. Moderate NW winds are expected to develop by Thursday in response to building high pressure over the Pacific to the WNW. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Across the Gulf of Papagayo, fresh to locally strong nocturnal northeast to east drainage flow that occurred this morning has diminished to fresh winds this afternoon. These winds will diminish further tonight and become light and variable on Monday. Seas peaked at around 8 ft Sunday morning. They will subside to 5 to 6 ft on Monday and to 4 to 5 ft by Tuesday. Across the Gulf of Panama, fresh northerly flow extends will S of the Gulf to near 04N where peak seas have built to 5 to 6 ft. winds will diminish to gentle to moderate tonight through Tuesday, while seas subside to 3-4 feet by Tuesday. Elsewhere, light to gentle winds and combined seas of 4 to 6 ft will prevail through early next week. REMAINDER OF THE AREA... ...A very progressive winter type pattern prevails over the northwest sector of the area... A 1020 mb high center analyzed near 25N126W and extends a ridge southwest to beyond 21N140W and also southeastward to just beyond the Revillagigedo Islands. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ is generating moderate to fresh northeast winds roughly from 04N to 16N west of 112W. Associated seas in this area run between 7 and 10 ft as northwest swell and northeast wind waves mix. The high pressure will continue to weaken as a cold front currently analyzed from 32N127W to 26N135W and stationary to 25N140W. As a result, the trades over the central and western portions of the forecast area will weaken through Monday night. Wave model guidance indicates that seas within this area of trades will subside below 8 ft by Tue morning. A series of cold fronts will continue to march over the northwest portion through early next week, with the next of these fronts forecast to move over that portion of the area late tonight into early Monday along a position from near 32N133W to 25N140W. High pressure building in behind the new cold front will cause fresh to strong NW winds to develop N of 24N and east of 120W on Wednesday and Thursday. Seas of 8 to 11 ft will cover a large area to the north of a line from 22N112W to 15N120W to 11N131W to 11N140W by Friday morning. $$ Aguirre