000 AXPZ20 KNHC 172130 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Tue Apr 17 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 1800 UTC surface analysis and satellite imagery through 2015 UTC. ...SPECIAL FEATURES... Gulf of Tehuantepec Gale Warning has ended. Gale force northerly winds have diminished to 20-25 kt this afternoon across and downstream of Tehuantepec, with seas estimated to have subsided to 8-11 ft. Supporting high pressure across the Gulf of Mexico is shifting ENE across the NE Gulf coast, and winds across the Bay of Campeche have begun to shift E to SE. Winds and seas will diminish quickly the remainder of this afternoon and evening. An extensive swath of large N to NE swell generated by this gap wind event will continue to propagate well to the SW of the Tehuantepec area, covering roughly the waters from 03N to 17N between 93W and 110W this afternoon. Tranquil conditions are expected across the Tehuantepec region late tonight through Thursday morning, before winds increase again, and produce a potential brief gale event Thursday night into Friday morning. Please refer to the East Pacific High Seas Forecast under AWIPS/WMO headers HSFEP2/FZPN03 KNHC for more details. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... A surface trough extends from 10N71.5W TO 06.5N79W TO 09N84W TO 05.5N90W. The ITCZ stretches from 05.5N90W TO 08N111W TO 07N119W TO 08N128W to beyond 07.5N140W. Scattered moderate to strong convection is from 02.5N to 08N E of 93W to the coast of Colombia. Scattered moderate to strong convection is also noted from 05N to 13.5N between 103W and 140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A cold front has swept across Baja California Norte and the northern Gulf of California today, and has become ill defined in satellite imagery. Strong NNW winds behind the front over the northern Gulf of California this morning have diminished to 15- 20 kt this afternoon and will shift SSE across central and south portions of the Gulf this evening and tonight. Otherwise, moderate to fresh NW-N winds are forecast across the offshore waters W of Baja California the remainder of the forecast period. Winds are forecast to increase again to 20-25 kt N of Punta Eugenia Thu night and Fri due to a tight pressure gradient between a ridge over the northern forecast waters and lower pressures over the SW CONUS and Mexico. Seas in the 8-10 ft range affecting the offshore waters W of Baja California this afternoon will begin to gradually subside on Wed, with seas falling to 5-8 ft by late Wed. Gentle to moderate NW winds are expected to prevail across the Gulf of California Wed through Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: Pulsing fresh to strong NE-E winds are expected across and downstream of the Gulf of Papagayo during the late afternoon through early morning hours each day through Fri. Gulf of Fonseca: An overnight scatterometer pass indicated northerly winds of 20-25 kt across the Gulf of Fonseca and downwind to near 12N. These winds are occuring behind a dissipating frontal boundary over the NW Caribbean Sea extending SW into central Honduras. Winds will remain fresh and gradually diminish to 15-20 kt this afternoon. Gulf of Panama: Fresh northerly winds are expected across the Gulf of Panama through Wed night, with seas of 4-6 ft. Elsewhere, light to gentle winds are expected through the forecast period, with a weak surface through meandering from 06N- 08N and yielding light S to SW winds to its south. Seas in the 3 to 5 ft range will continue over most of the area. Cross equatorial SW swell will mix with residual swell from Papgayo tonight through Fri and raise seas to 5-7 ft S of 10N. REMAINDER OF THE AREA... As previously mentioned, a cold front has swept across the northern Baja California peninsula and become ill defined across NW Mexico this afternoon. A 1029 mb high pressure located near 34N130W prevails NW of the old front, and extends a ridge across the northern forecast waters, including the entrance of the Gulf of California and Las Tres Marias islands. This system will weaken some over the next 24-48 hours, and then will be reinforcing by a stronger high pressure by late Thu. Large NW swell continues to propagate southeastward through the forecast waters, with max seas of around 10 ft. This swell is mixing with waves generating in the Tehuantepec area. As a result, seas of 8 ft or greater will cover most of the area W of 108W today. Cross equatorial SW swell has moved into the southern forecast waters this morning. Marine guidance suggests that seas of 8-10 ft will dominate the waters S of 04N between 97W and 120W by early this evening. Seas are forecast to subside to 8 ft or less across most of the area W of 120W by late Wed. At that time, seas of 8-10 ft are expected mainly S of 10N between 92W and 120W. $$ Stripling