000 AXPZ20 KNHC 282151 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Apr 28 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 2030 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from Costa Rica near 10N85W to 08N90W. The ITCZ continues from 08N90W to 04N103W TO 05.5N122W, then resumes from 04.5N125W to beyond 04N140W. Widely scattered moderate isolated strong convection is seen within 120 nm either side of the ITCZ between 93W and 110W. Scattered moderate to strong convection is noted within 150 nm N and 90 nm S of the ITCZ between 120W and 139W. Scattered moderate convection is from 09N to 11N between 113W and 118W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A ridge of high pressure extends SE from collapsed surface high pressure formerly near 24N125W to south of the Revillagigedo Islands near 16N110W. A deep layered upper level low pressure system has carved a surface trough that extends from 30N124W to 25N132W, which has acted to weaken the ridge. The pressure gradient on the eastern periphery of the ridge is maintaining gentle to moderate NW to N winds over the offshore waters of Baja California. Seas continue 4 to 5 ft in northerly swell across the area. A band of moderate convection initiated by the upper level low is moving slowly eastward across the far outer waters, within 45 nm E of a line from 30N118W to 27.5N120W. This weather is expected to move inland across Baja California Norte late tonight. With the exception of winds briefly becoming fresh along and just offshore the central part of the Baja California Peninsula during the afternoons and at night, expect near steady state conditions through Thu night. Fresh N swell will propagate southward into the region Mon, then affect the offshore waters N of 27N through Tue night. This will cause seas in this area to build about a foot higher, then seas will subside back to the current 4 to 6 foot range Thu. Light to gentle NW to W winds prevail across the offshore waters between Las Tres Marias and Puerto Angel this afternoon, where seas are generally 4 to 5 ft in mixed SW and NW swell. Little change in overall conditions are expected through Wed, with afternoon winds turning more onshore and increasing to around 15 kt each day. Gulf of California: Moderate to fresh S to SW winds across far north portions of the Gulf this afternoon will become strong from the SW Mon night and Tue, as a weakening trough approaches. Winds will then diminish to fresh around midday Tue then become generally light to gentle S to SW winds Tue afternoon through Thu night. Seas over the northern part of the Gulf are presently 3 ft or less, but will build to 5 to 7 ft on Mon, then subside to 2 to 4 ft on Tue as winds diminish. Gulf of Tehuantepec: Light to moderate onshore winds and seas ranging between 4 and 6 ft are expected for the Gulf of Tehuantepec through Thu night. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Fresh NE to E winds over the Gulf of Papagayo region will become strong tonight through Thu night. Gulf of Panama: Fresh N winds over the Gulf of Panama will become light to moderate tonight. Seas in this area will be maintained in the 3 to 5 ft range as a result of the long-period S to SW swell originating from the Southern Hemisphere. Satellite-derive altimeter data from near noon today suggested seas between Ecuador and the Galapagos Islands ranging 4-6 ft in S to SW swell. This S to SW swell will maintain combined seas near current heights through Wed, then seas will subside slightly Wed night through Thu night. Visible GOES-16 satellite images received this morning clearly depicted a widespread area of haze, some of it dense, along and adjacent to the coast of Central America and the coast of SE Mexico, including the Gulf of Tehuantepec region. The imagery revealed that the haze had spread SW as far as 10N100W. This area closely correlates with the smoke guidance issued by NOAA/NESDIS. Ongoing agricultural burning, as normally carried on during this time of year in SE Mexico and in Central America is generating smoke leading to the hazy conditions. Latest surface based observations highlight reduced visibility of 2 to 6 nm. The smoke could persist over the region for at least several days if burning continues while light to moderate NE low- level winds continue across this region. REMAINDER OF THE AREA... Moderate to fresh NE to E trades are observed over the waters from about 04N to 16N and W of 120W. NW and SW swell will help maintain combined seas in the range of 6 to 8 ft. Rather weak high pressure ridging over the northern waters will generally maintain moderate trades across the trade wind belt through early next week, with little change in combined seas expected. New N swell producing seas of near 8 ft and higher will cross 32N and between 124W and 132W Mon and propagate southward to near 28N between 121W and 133W by late Mon night. These conditions will linger through Tue. Cross-equatorial SW swell will propagate NE through much of the forecast area east of 120W through Mon night, then Tue through Thu. Combined seas of 8 ft or higher will generally be confined to the waters south of the 02S and west of 95W. Wave model guidance remains consistent in forecasting a more robust Southern Hemisphere swell event that will arrive on the Equator by Thu night. A large portion of the discussion area S of 10N and W of 110W could experience seas between 8 and 9 ft by Fri night. $$ Stripling