000 AXPZ20 KNHC 062123 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 2205 UTC Sun Aug 6 2017 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 2100 UTC. ..TROPICAL WAVES... A tropical wave axis is along 100W north of 07N, moving west at 10-15 kt. The wave is embedded within an area of deep layered moisture as noted on the TPW animation. The 700 mb streamline analysis from the GFS suggests that a trough is over and near the location of the wave. Latest satellite imagery shows scattered moderate to isolated strong convection on the east side of the wave axis from 07N to 14N between 95W and 100W, and scattered moderate convection on the west side of the wave axis from 07N to 13N between 100W and 105W. Lightning density data indicates frequent lightning with some of the observed convection. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11N85W to 10N100W to 09N115W to 12N130W to 12N134W. The ITCZ continues from 12N134W to beyond 11N140W. Scattered moderate isolated strong convection is from 08N to 12N between 88W and 92W. Scattered moderate convection is noted from 07N to 10N between 109W and 118W, and from 10N to 14N between 129W and 138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A low pressure system, remnants of recent Tropical Depression Eleven-E, is centered near 21N112W with a pressure of 1011 mb. It is nearly stationary at the present time. Experimental GOES16 shows a very well defined swirl of mainly low clouds associated with the remnant low. A ship located within 150 nm NE quadrant of the low center reported SE winds of 20 kt. Associated winds and seas will continue to diminish as the low continues to weaken. A ridge will dominate the offshore waters to the west of northern and central Baja California. Expect gentle to moderate NW to N winds and seas in the range of 4 to 5 ft west of the Baja California peninsula. Gentle to locally moderate southerly flow will prevail across the Gulf of California. Gulf of Tehuantepec: light and variable winds will prevail through tonight, then become moderate northerly winds early on Monday, with the assistance of nocturnal drainage flow. Wave model guidance has been consistently suggesting that a new set of long-period southerly swell, with the leading edge containing a period of 20 to 21 seconds, is forecast to reach the coast of Mexico south of Cabo Corrientes on Tuesday. This scenario will bring the potential for large breaking waves as it reaches shallow waters along the coast of Mexico on Tuesday. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The Gulf of Papagayo: gentle to moderate southwest to west winds will change little offshore the Gulf of Papagayo through Tuesday with seas of 5 to 6 ft in southerly swell. Moderate southerly winds are expected to the south of the monsoon trough, with gentle and variable winds to the north of the monsoon trough, with seas generally in the 4 to 6 ft range. A set of long-period southerly swell, with a leading edge period of 20 to 21 seconds, is forecast to reach the waters between Ecuador and the Galapagos Islands early Monday, and the coast of Central America on Tuesday. Seas are expected to build to the range of 6 to 7 ft mainly over the offshore waters of northern Costa Rica and western Panama on Tuesday, with some potential for large breaking waves as it reaches shallow waters along the coast. REMAINDER OF THE AREA... A surface ridge will build across the northern forecast waters, as the remnant low of Tropical Depression Eleven-E gradually opens up into a trough by late Monday. Moderate to locally fresh trade winds are expected around the southern periphery of the ridge and to the north of the convergence zone, mainly from about 12N to 20N and west of 125W, with associated seas in the range of 5 to 7 ft. Weak low pressure is expected to form on the monsoon trough near 12N137W by early on Monday, and move little through Tuesday. $$ GR