000 AXPZ20 KNHC 160406 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 405 UTC Sun Apr 16 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 0300 UTC. ...Special Features... A strong cold front has moved into the far northwest corner of the area and extends from 30N137W to 27N140W. Ahead of the front the pressure gradient has tightened and strong to near gale force south to southwest winds are occurring west of a line from near 32N132W to 27N137W, with seas building 8 to 10 ft. Southerly minimal gale force winds are close to the forecast area, generally along and north of 32N with seas in the 10 to 12 ft range. These conditions are expected to move further N of the area overnight as the cold front extends from 30N134W to 26N140W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The northern Intertropical Convergence Zone axis extends from 04N93W to 03N115W to 03N130W to 02N140W. Scattered moderate isolated strong convection is within 240 NM N of the the axis between 127W and 134W. Scattered moderate convection is within 120 NM either side of the axis between 98W and 107W. The southern Intertropical Convergence Zone axis extends from 03.4SN90W to 03.4S105W to beyond 03S120W. Scattered moderate to strong convection is within 90 NM of axis between 100W and 110W and within 60 NM of the axis between 114W and 117W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... The pressure gradient between high pressure over eastern Mexico and lower pressures south of the Tehuantepec region will once again allow northerly winds to pulse back up to 20-25 KT late tonight into early Sunday aided by nocturnal drainage flow. The high pressure will shift eastward as low pressure develops over the southern plains on Sunday, allowing the pressure gradient to slacken on Sunday afternoon, at which time the northerly winds become light to gentle southwest to west winds. Seas should remain 5 to 7 ft on Sunday and subside to 4 to 5 ft on Monday. The pressure gradient along the west coast of the Baja California Peninsula is loosening up, and the recent strong northwest along and offshore the peninsula have diminished to fresh category. These winds will diminish further to the moderate range this afternoon, and remain at generally the moderate range with possible brief episodes of fresh winds through Monday. Seas of 7 to 9 ft offshore Baja California Norte will subside to 6 to 7 ft on Sunday. The pressure gradient associated with high pressure building in behind a cold front that will dissipate to the west of the Baja California Peninsula will begin to induce fresh to strong northwest winds along the extreme northern section of the Baja California Norte Peninsula beginning late Monday night. Seas start to build to 6 to 8 ft with these winds, then gradually continue to build thereafter. Light and variable winds and seas generally below 2 ft will prevail across most of the Gulf of California through Monday as the pressure gradient remains loose along the Baja California Peninsula. Seas of about 3 to 4 ft are expected near the entrance of the Gulf through Monday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, fresh to locally strong nocturnal northeast to east drainage flow is expected to begin again tonight and diminish to fresh category Sunday afternoon and remain at fresh intensity through Monday. Seas are expected to reach the range of 6 to 8 ft tonight before lowering to less than 8 ft this afternoon. In the Gulf of Panama, moderate to fresh northerly flow will diminish to mostly moderate winds this afternoon, then briefly to fresh to strong tonight before diminishing to moderate to fresh Sunday morning and to gentle to moderate Sunday afternoon. Seas will be 5 to 6 ft downstream of the Gulf. Elsewhere, light to gentle winds and combined seas of 4 to 6 ft will prevail through into early next week. REMAINDER OF THE AREA... See Special Features above for more details on gale conditions associated with the next cold front to move into the northwest portion of the area by early this afternoon. A set of northwest swell producing seas of 8 to 9 ft in the far northeast portion of the area will gradually decay through Sunday, with seas lowering to 6 to 7 ft. A 1023 mb high pressure cell centered well north of area near 35N126W ridges S to 30N127W, then southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressures in the vicinity of the ITCZ is generating moderate to fresh NE winds roughly from 06N to 18N west of 137W, and from 06N to 22N between 119W and 137W. Associated seas are between 8 and 9 ft in mixed northwest swell and northeast wind waves. The high pressure will be displaced eastward as it weakens due to the approaching cold front. As a result, the trades over the central and western portions of the forecast area will weaken through Monday. Wave model guidance indicates that seas within this area of trades will subside below 8 FT by late Sunday. Another cold front will move across the far northwest waters on Monday followed by strong northwest winds and seas to 9 ft. $$ cam