000 AXPZ20 KNHC 230350 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 152 UTC Mon Apr 23 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 0000 UTC surface analysis and satellite imagery through 0245 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 09N73W to 06N85W to 05N95W. The ITCZ continues from 05N95W to 05N110W to 04N125W to beyond 05N140W. Scattered moderate and isolated strong convection is present from 04N to 10N between 82W and 86W, from 05N to 11N between 106W and 110W, within 120 nm either side of a line from 13N113W to 05N119W and within 120 nm either side of a line from 04N130W to 12N135W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Moderate NW winds and seas of 5 to 7 ft currently prevail across the offshore waters of Baja California as ridging from the NW and lower pressure over the SW United States and NW Mexico combine to maintain a modest pressure gradient over the area. Winds W of the peninsula will gradually diminish through Tue as the high to the NW weakens and lower pressure over the SW United States and NW Mexico fills and shifts east. However, NW swell will help to maintain seas in the 5-7 ft range through Monday, except around 8 ft to the N through W of Isla Guadalupe. Winds and seas will then diminish very slightly Mon night through Wed. Light to gentle variable winds prevail throughout the Gulf of California, and are expected to persist through Wed as the high gradually weakens and the area of low pressure weakens and moves east. Winds across the Gulf of Tehuantepec region are light and variable. Another cold front moving across the NW Gulf of Mexico today and tonight will induce the next mild gap wind event over the Gulf of Tehuantepec Mon through Thu. A small plume of N to NE winds will periodically affect the immediate Gulf waters, and will be strongest during nocturnal drainage flow. Gales are not expected during this event. 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 between nightfall and mid morning to 20-25 kt across and downstream of the Gulf of Papagayo through at least Tue night with seas peaking each episode between 6 and 8 ft. Winds over the Gulf will be lighter Wed through Fri as high pres N of the Caribbean weakens. Gulf of Panama: Gentle to moderate N to NE winds and seas of 3 to 6 ft in SW swell prevail across the Gulf of Panama and offshore of Panama and Colombia to 250 nm this afternoon. Active convection continues across the region this evening near and S of Panama and Costa Rica from 04N to 10N between 82W and 86W as showers and thunderstorms produce strong gusty winds and rough seas. A surface trough extending WSW from the border of Panama and Colombia is acting as a focus for the convection. Winds across the Gulf will remain gentle to moderate tonight through Fri, while farther offshore and SW, gentle to moderate SW winds will prevail through Fri. Corresponding seas will generally run between 4 and 6 ft. Elsewhere, mainly light to gentle winds are expected S of 08N through Fri. Cross-equatorial swell will mix with residual swell downwind from Papagayo through Wed, 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, then rebuild to between 5 and 7 ft Mon through Wed as another round of SW swell arrive. REMAINDER OF THE AREA... High pressure centered well offshore of Northern California near 36N134W has begun to weaken and shift NE as a new cold front approaches 140W from the NW. The high continues to ridge SE across the northern forecast waters to near the Revillagigedo Islands. The pressure gradient between the ITCZ and the high will remain strong enough to support fresh NE trades N of the ITCZ generally between 08N and 22N W of 125W through Thu. The combination of these winds, NW swell and SW swell will support combined seas of 7 to 9 ft over these waters. Active convection continues across this trade wind belt this afternoon as a deep layered trough just to the NW is maintaining unstable conditions aloft. A cold front will reach the far NW corner of the discussion area Tue morning, preceded shortly by the next pulse of NW swell. The front will dissipate as it moves beyond 28N137W on Wed as fresh to locally strong winds affect the far NW waters. Seas in excess of 8 ft will only briefly impact the NW waters during this time. A new pulse of SW swell is moving into the equatorial waters W of 100W this evening, and will spread NE towards the offshore waters through Wed. This cross-equatorial swell will combine with NW swell to create an even larger area of 7 to 9 foot seas S of 20N and W of 100W Tue through Thu. $$ CAM