000 AXPZ20 KNHC 160937 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Wed May 16 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 0600 UTC surface analysis and satellite imagery through 0915 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from northwestern Colombia to across Panama and to 08N95W to 10N92W to 09N110W to 05N130W, where it ends. The ITCZ axis begins at 07N123W and ends at 04N132W. Scattered strong convection is noted from 09N to 11N between 120W and 125W, also within 60 nm south south of trough between 84W and 87W and within 60 nm north of trough between 111W and 113W. Scattered moderate isolated convection is seen within 240 nm south of trough between 108W and 112W and within 60 nm either side of trough between 98W and 105W. Scattered moderate convection is within 60 nm north of the trough between 113W and 117W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE oriented high pressure ridge prevails across the offshore waters west of Baja California, producing fresh NW to N winds over those waters. These winds will increase to fresh to locally strong speeds this afternoon through Fri as the ridge strengthens slightly. Seas over these waters are in the 5-7 ft range, and will build slightly Wed through Thu to 6-8 ft as the winds freshen across these waters. Gulf of California: Light and variable winds are over the northern Gulf of California this afternoon, while gentle to moderate NW winds continue across the remainder of the Gulf. Little change is today, except for fresh NW onshore winds along the coast of Mexico from 24N to 26N through early Thu. Gulf of Tehuantepec: Gentle to moderate variable winds are expected to prevail across the Gulf region through Fri as a weak pressure pattern remains over southeastern Mexico and the Yucatan Peninsula. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Light to gentle winds will dominate the gulf most of the forecast period as a weak pressure remains across Central America. Seas of 4-6 ft over the gulf and nearby waters will continue through early Thu, then build slightly higher reaching 7 ft Thu night and to 5-8 ft beginning late on Sat in response to a pronounced pulse of cross equatorial SW swell. The highest seas of this range are forecast to be near the 250 nm boundary of the offshore waters. Gulf of Panama: Gentle to moderate S to SW winds are forecast during the next several days, with seas of 4-6 ft in long period SW swell, building a little to 5-7 ft today through the next few days as the swell reaches the coasts of Panama and Colombia. Expect increasing wave action along those coasts. Elsewhere, gentle to moderate SW winds are expected to the south of the monsoon trough with its axis roughly along 09N/10N, with light to gentle variable winds north of trough as a weak pressure pattern remains over Central America. Seas are forecast to build to 6-7 ft in long period SW swell between Ecuador and the Galapagos Islands beginning today and continuing through the next few days. Wave mode guidance indicates that these seas will build to the range of 6-9 ft. Scattered strong convection developed during the overnight hours just offshore and just inland the coast of Guatemala within 30 nm of a line from 11N87W to 13N89W, and also within 30 nm of 14N92W and over the Gulf of Tehuantepec within 30 nm of 16N94.5W. Expect for this activity to remain active through the morning as it moves in a west to west-southwest direction. REMAINDER OF THE AREA... A 1019 mb high is centered at 29N125W, with a ridge axis extending southeastward to near the Revillagigedo Islands. The pressure gradient between the ridge and lower pressure in the tropics is rather weak allowing for moderate to at time fresh NE-E trades from 09N to 22N and west of 115W. Seas across this area of trades are 6-8 ft, and should change little through Thu. The ridge will shift slightly southeastward through tonight, with the resultant pressure gradient forecast to induce a slight increase of trades across the tropics. Stronger high pressure is then forecast to build southeastward over the northern and central portions of the discussion area Thu through Fri. This will tighten the pressure gradient allowing for trades to increase to fresh to locally strong speeds trades from 09N to 18N west of about 125W along with seas building slightly to around 9 ft. N of 22N, seas are 5-6 ft west of 118W and are expected to change little through early Fri, except in the far northeastern part of the area the seas are expected to build some during Fri as long-period SW swell combines with NW swell. $$ Aguirre