000 AXPZ20 KNHC 272143 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2021 UTC Sat Apr 27 2019 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 2100 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from just W of the coast of Costa Rica near 09N85W to 04.5N98W to 04.5N102W, where it transitions to the ITCZ and continues to 04.5N120W to 06N136W to beyond the discussion area at 06N140W. Scattered moderate and isolated strong convection is noted within 90 nm either side of the trough from 89W to 102W and within 60 nm either side of a line from 07N115.5W to 05.5N105.5W. Scattered moderate convection is present from 03N to 06N between 102W and 105W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Relatively weak 1018 mb high pressure is centered W of the offshore waters near 27N124W. The pressure gradient on the E side of the high is maintaining gentle to moderate NW to N winds over the forecast waters. Seas are in the 4 to 6 ft range. With the exception of winds briefly becoming fresh along and just offshore the central part of the Baja California Peninsula this afternoon, expect near steady state conditions through Thu. Fresh N swell is forecast to cross 32N on Mon and affect the offshore waters N of 27N through Tue night, causing seas there to build around a foot, before they subside back to the 4 to 6 foot range Thu. Gulf of California: Fresh SW winds will develop over the northern Gulf of California tonight and become strong Mon night and Tue as a weak trough approaches. Seas N of 30N will build to 4-6 ft during this time frame. Winds will then diminish to fresh around noon Tue then become light to gentle S to SW winds Tue afternoon. Gulf of Tehuantepec: Winds across the Gulf of Tehuantepec overnight have diminished to less than 20 kt as high pressure over the Gulf of Mexico shifts E. Wave heights of 8 to 9 ft in merging N and SW swell still reach as far downstream as 12N96W. Winds will diminish to around 10 kt and wave heights fall below 8 ft this evening. Variable winds at less than 20 kt will then prevail across the Tehuantepec region through the first part of next week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to fresh NE winds over the Gulf of Papagayo region will become strong Mon night through Tue night. Highest winds and seas will occur at night. Gulf of Panama: Moderate N winds will diminish to gentle Sun night, then remain gentle through Thu. Seas in this area will be maintained in the 3 to 5 ft range by S to SW swell arriving from the Southern Hemisphere. Combined seas between Ecuador and the Galapagos Islands are in the 5 to 7 ft range in S to SW swell based on the latest altimeter data in this region. Long-period S to SW swell will maintain seas between 5 and 7 ft for the offshore waters west of Ecuador through Wed night. Satellite imagery continues to confirm weather observations of smoke along the Central American coasts. Ongoing agricultural burning during the past few days across SE Mexico and Central America have been transported SW over the Pacific offshore waters, and can be seen in satellite imagery from the Gulf of Tehuantepec to well offshore of the Gulf of Papagayo to 08N92W. Observations suggest visibilities are reduced to the 3-5 nm range. This smoke may take several days to clear the region as fires continue and moderate NE low level winds prevail across the region. REMAINDER OF THE AREA... Moderate NE to E trades are generally present over the waters from 06N to 17N and W of 110W. Altimeter data from this afternoon from this area suggests that corresponding wave heights are in the 6 to 8 ft range. Rather weak high pressure over the northern waters will maintain moderate trades across the trade wind belt through early next week as seas remain in the 6 to 8 ft range. A weakening 1016 mb surface low is analyzed near 30N131W, with a trough extending WSW from the low to 25N139W. The low is producing little in the way of sensible weather. The low is tacking slowly ENE and is forecast to head slowly E while dragging the trough over the northern waters tonight through Mon. Winds in the vicinity of the low are expected to remain less than 20 kt with seas 6 to 7 ft across the far NW waters. Higher seas, likely to peak at 8 or 9 ft, are forecast to move into the north- central waters north of 28N on Mon as fresh north swell propagates through those waters. The low is expected to weaken into a trough before it reaches the coast of Baja California Norte Mon night. Cross-equatorial SW swell in the far southern waters will spread northward across much of the forecast area east of 120W through Mon night, then subside. Seas to 8 ft will generally be confined to the waters south of the 01N and west of 95W. A more robust round of Southern Hemisphere swell could cross the Equator by Thu night. $$ CAM