000 AXPZ20 KNHC 202203 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Fri Apr 20 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 2045 UTC. ...SPECIAL FEATURES... Northerly winds across and downstream of the Gulf of Tehuantepec continue to gradually diminish this afternoon, and have fallen to around 25 kt with gusts to 30 kt. Seas are slowly subsiding and are now down to 8-12 ft. The gale warning for the area has been discontinued. Winds will further diminish in areal coverage, with strong N winds to 25 kt becoming confined to within about 90 nm of the coast evening and tonight. Supporting high pressure across the southern U.S. behind a stalled cold front over the northern Gulf of Mexico is shifting slowly eastward, and is allowing the pressure gradient across the Isthmus of Tehuantepec to gradually weaken. Winds will become light and variable and seas will subside below 8 ft by Sat evening. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 07.5N77W TO 05N81W TO 08N105W TO 06N118W. The ITCZ continues from 06N118W TO 07.5N124W to beyond 06.5N140W. Scattered moderate to strong convection is present from 04N TO 08.5N E OF 87W to the coast of Colombia, within 60 nm N and 120 nm S of the trough between 90W and 110W, and from 06N to 13N between 104W and 127W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Fresh NW winds and seas of 5 to 8 ft prevail across the offshore waters of Baja California as a tight pressure gradient exists between a ridge building in from the NW and lower pressure over the SW United States and NW Mexico. NW swell following a front that swept through the area last night will maintain seas at 5-8 ft through tonight. Winds and seas W of the peninsula will then diminish Sat through Mon as the high to the NW weakens. Moderate NW winds prevail over the N Gulf of California, while fresh NW winds are observed through the central Gulf. Winds will subside over the Gulf Sat and Sun as the high weakens slightly and the area of low pressure moves east. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh NE to E winds across the region are expected to pulse at night through morning to 20-25 kt across and downstream of the Gulf of Papagayo through at least Tue night with seas peaking each night between 7 and 9 ft. Gulf of Panama: Fresh northerly winds and seas of 5 to 7 ft in SW swell prevail across the Gulf of Panama and offshore of Panama and Colombia to 250 nm today. Very active convection overnight continues from 04N TO 08.5N E OF 87W to the coast of Colombia, and is likely producing strong gusty winds and very rough seas to near 8 ft this afternoon. Northerly winds will become gentle to moderate Sat through Sun across the Gulf of Panama, while farther offshore and SW, gentle to moderate SW winds will develop. Seas will generally run between 4 and 6 ft. Elsewhere, mainly light to gentle winds are expected S of 06N through Tue. Cross-equatorial swell will mix with residual swell downwind from Papagayo through Tue, and maintain seas in this area between 5 and 7 ft. Elsewhere seas will subside to 3-5 ft by Sun as long period SW swell from the Southern Hemisphere decay. REMAINDER OF THE AREA... A 1030 mb high pressure center was located north of the forecast area near 34N134W. The high ridges SE across the northern forecast waters to near the Revillagigedo Islands. The high will be reinforced by stronger high pressure building in behind the last nights dissipated cold front through Sat before weakening. Cross equatorial SW swell moving into the southern forecast waters will affect the waters near the equator between 98W and 120W today. Seas will subside to 8 ft or less across most of this area today by this evening. Another round of SW swell could cause waters near the equator to build to 8 ft or above by early next week. The pressure gradient between the ITCZ and building high pressure to the north will support fresh to strong NE trades N of the ITCZ generally between 09N and 20N W of 125W through Saturday. The combination of these winds, NW swell and SW swell will support combined seas of 8 to 11 ft over these waters into Saturday, expanding N to 30N by Sunday as NW swell propagates into the northern waters. The NW swell will begin to decay below 8 ft Sunday night before becoming reinforced by another pulse of NW swell by Monday night. $$ Stripling