529 AXPZ20 KNHC 240845 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 621 UTC Tue Jul 24 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 0815 UTC. ...TROPICAL WAVES... A tropical wave has an axis from 04N92W to 13N92W, moving westward between 20 and 25 kt. The wave remains evident in tropical wave model diagnostics as well as a maximum in total precipitable water satellite imagery. Scattered moderate convection is evident from 06N to 08N between 90W and 94W. A tropical wave has an axis extending from 04N103W to weak low pres 1010 mb near 08.5N103W to 15N102W, moving westward around 15 kt. The wave is evident in 700 mb tropical wave model guidance streamlines as well as a pronounced maximum in total precipitable water satellite imagery. Scattered moderate and isolated strong convection is seen from 07N to 14N between 100W and 108W. A tropical wave has an axis extending from 04N132W to low pres 1010 mb near 12N132W to 16N132W, moving westward around 15 kt. The wave is associated with broad troughing at 700 mb as depicted in model guidance. The low embedded along this wave remains rather compact as observed in the latest satellite-derived wind imagery. Scattered moderate isolated strong convection is seen from 09N to 15N between 129W and 134W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from a 1010 mb low over NW Colombia near 10N75W to 08N84W to 10N96W to 08N106W to low pres 1009 mb near 12N121W to 13N130W to beyond 09N140W. Aside from convection associated with the tropical waves, numerous moderate and scattered strong convection is taking place from 10N to 13N between 121W and 124W. Scattered moderate and isolated strong convection is present elsewhere from 09N to 14N between 120W and 124W. Scattered moderate and isolated strong convection is occurring from 05N to 10N E of 80W and from 09N to 14N between 112W and 115W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A high pres ridge extends SE from 1022 mb high pressure centered near 30N129W to 19N119W to ESE of the Revillagigedo Islands near 17N106W. The ridge is maintaining light to moderate NW winds across the Mexican offshore waters. Little change is expected in these conditions during the next several days. A long period SW cross-equatorial swell is affecting all of the waters S of 25N. This extensive swell event is peaking and is bringing seas ranging between 7 and 9 ft to the open waters for all the forecast zones. Seas will begin to slowly subside today, then continue to slowly subside for the rest of the week. Gulf of Tehuantepec: Gentle S of SW winds are expected tonight and then gentle to variable winds on Tue. The area of 8 ft seas generated by gap winds during the past couple of days has merged with the much larger area of 8 ft seas that arrived from the S today. Seas in this area will gradually subside through the end of this week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo: NE to E winds will pulse to fresh speeds during the late night and morning hours for the remainder of this week. Seas from these winds are interacting with the SW swell event resulting in mixed seas in the gulf between 8 and 9 ft. Seas in this area will subside below 8 ft on Wed. Gentle to moderate NE to E winds are forecast elsewhere N of the monsoon trough which will meander west of Central America between 07N and 10N. Moderate to fresh S to SW winds are generally expected S of the trough axis during the next several days. A long-period SW cross-equatorial swell event encompasses just about the entire region. Maximum combined seas of 8 to 10 ft are currently focusing between the Equator and 15N between 90W and 105W. Wave model guidance suggests that seas are peaking and will gradually subside to around 8 ft Wed, and then to less than 8 ft Thu. REMAINDER OF THE AREA... A surface ridge extends SE from 1022 mb high pressure centered near 30N129W to 19N119W to ESE of the Revillagigedo Islands near 17N106W. The gradient between the ridge and lower pressure found along and near the monsoon trough is maintaining moderate to fresh NE trade winds north of the monsoon trough, south of 20N and west of 115W. Little change in this pattern is expected for the upcoming week. Low pressure of 1010 mb is located near 11.5N along the tropical wave that extends from 04N131W to 17N130W. The low will generate fresh to strong winds and 8 to 10 ft seas in its N quadrant as it tracks WSW to cross 140W Wed evening. Another low measuring 1009 mb is currently centered near 12N121W. This low will track WSW to near 10N132W by Thu morning. Fresh to strong winds and seas of 8 to 9 ft can be expected in the N quadrant of this low during this time frame. Large long-period SW swell continues crossing the equator, with seas of 8 to 11 ft affecting almost all of the waters S of 25N as confirmed by satellite-derived sea height data. Wave model guidance indicates that swell heights are peaking and that seas in this extensive area will slowly subside through the end of this week. Seas in this area should subside to 8 ft or less by Thu morning. $$ CAM