000 AXPZ20 KNHC 271000 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning: The earlier strong north winds across the Gulf of Tehuantepec increased to minimal gale force during the overnight hours as the pressure gradient has tighten over southeastern Mexico. These winds will diminish to just below gale force at or just after daybreak this morning as the gradient begins to weaken. Wave heights resulting from these winds are most probable in the range of 8-11 ft and while at the same time an area of wave heights in the range of 8-10 ft arising from north to northeast swell exists elsewhere from 12.5N to 15.5N between 94W and 96W. As the gap wind event begins to shut down this afternoon, wave heights will lower to a peak of 8 ft in merging north and southwest swell to be confined in a narrow line downstream of the Gulf that will reach to near 12N96W. Wave heights then lower to less than 8 ft early this evening. Please refer to the East Pacific High Seas Forecast issued by the National Hurricane center under AWIPS/WMO headers FZPN03 KNHC/HSFEP2 or at the website https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more specific marine details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A trough extends from a 1010 mb low over northern Colombia near 10N74W to the coast at 07N77W and continues to 06N81W to 06N89W, where it transitions to the ITCZ and continues to 07N104W to 06N113W to 04N121W to 06N133W and to beyond the area at 07N140W. Scattered moderate to isolated strong convection is within 180 nm north of the ITCZ between 107W-111W. Scattered moderate convection is within 120 nm south of the ITCZ between 100W-103W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Relatively weak high pressure remains over the offshore waters, centered on a 1020 mb high near 27N121W. The associated pressure gradient is maintaining gentle to moderate northwest to north 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 Sun night. A set of north swell is forecast to cross 32N and affect the northern offshore waters on Mon bringing seas of 5 to 7 ft there through Tue night, before subsiding slightly. Light to gentle northwest to north winds are present across the waters from Las Tres Marias to Puerto Angel, with seas of 4 to 5 ft in mixed swell in response to the ongoing Gulf of Tehuantepec gap wind event. These winds will then shift back to northwest to north in direction from Sun through early next week. Gulf of California: Fresh to strong southwest winds will develop over the northern Gulf of California Sun night through Mon night as a weak trough approaches. These winds diminish to fresh winds early Tue and become light to gentle south to southwest winds Tue afternoon. Seas will be 3 ft or less, with the exception of seas building to 4 to 6 ft in the far northern part on Mon. Gulf of Tehuantepec: See above for details regarding a short- lived and late season ongoing gale event. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Moderate to fresh northeast 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 northerly winds will diminish to gentle Sat, then remain gentle through Tue night. Seas in this area will be maintained in the 3 to 5 ft range by south to southwest swell arriving from the Southern Hemisphere. Wave heights between Ecuador and the Galapagos Islands are in the 5 to 7 ft range from south to southwest swell based on latest altimeter data in this region. Long-period south to southwest swell will maintain seas between 5 and 7 ft for the offshore waters west of Ecuador through Wed night. REMAINDER OF THE AREA... Moderate northeast to east trades are generally present over the waters from 07N to 17N and W of 123W and from 07n to 14N between 114W and 123W. Altimeter data from last night across this area suggested 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 tradewind belt through early next week with seas in the 6 to 8 ft range. An upper-level low is moving eastward across the northwest portion of the discussion, while at the surface a weakening low pressure center of 1016 mb is analyzed near 28N135W, with a trough extending from the low to west of the area at 27N140W. The upper low is producing scattered showers and isolated thunderstorms north of 28N and between 124W and 133W. The surface low is nearly stationary, but is forecast to slowly move eastward along 29N while dragging the trough over the northern waters through tonight. Winds in the vicinity of the low are expected to remain less than 20 kt with seas 6 to 7 ft across the far northwest waters. To the east and southeast of the low to 125W expect variable winds generally less than 15 kt and seas around 5 ft building to 5 to 7 ft in north swell Sun night through Mon. 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 a set of north swell propagates through those waters. Cross-equatorial southwest swell in the far southern waters will spread northward across much of the forecast area east of 120W through this weekend. Seas to 8 ft will generally be confined to the waters south of the 03N and west of 95W. $$ Aguirre