000 AXPZ20 KNHC 080235 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0230 UTC Tue Aug 8 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 0000 UTC surface analysis and satellite imagery through 0200 UTC. ..TROPICAL WAVES... A tropical wave extends along roughly 106W, south of Manzanillo Mexico, from 11N to 17N moving west at 10 kt. Cyclonic turning is noted in earlier satellite derived high density winds in this area. No significant convection is noted outside area of the monsoon trough as described below. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 11N86W to 10N116W. The intertropical convergence zone reaches from 14N127W to 11N140W. Scattered moderate to isolated strong convection is noted from 08N to 13N between 95W and 110W. Scattered moderate convection is noted within 120 nm north of the intertropical convergence zone. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A 1009 mb low pressure center, remnants of recent Tropical Depression Eleven-E, is centered near 21N111W and remains nearly stationary. Latest satellite imagery shows a swirl of low to mid- level clouds within 75 nm either side of the low center. Isolated showers are possible with these clouds. A scatterometer pass from 17 UTC indicated mainly gentle cyclonic winds within about 75 nm of the center. The low is forecast to become a trough by Wednesday as it drifts southeastward to the vicinity of the the Revillagigedo Islands. Elsewhere, weak ridging extends along roughly 27N. The gradient between the ridge and lower pressure over Colorado River basin is supporting moderate to fresh northerly winds off the northern coast of Baja California Norte. The ridge is maintaining generally light to gentle winds elsewhere with 4 to 6 ft seas in southerly swell. Wave models are indicating a reinforcing round of long period southerly swell may move into the region by Fri. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... 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 coastal areas of Costa Rica and Panama beginning this evening and Tuesday. Wave model guidance is suggesting that wave heights will build to the range of 6 to 7 ft mainly over portions of the offshore waters of Costa Rica and Panama on Tuesday, with some potential for large breaking waves as it reaches shallow waters along the coast. Scattered moderate to strong convection is just west of Colombia within 30 nm of a line from 03N78W to 06N78W. This activity is expected to last during the next 24 to 48 hours. REMAINDER OF THE AREA... Surface ridging across the area is forecast by the models to build some southeastward through Wednesday as the parent high of located well to the northwest of the area drops southeastward. This will push the remnant low of Tropical Depression Eleven-E southeastward towards the vicinity of Revillagigedo Islands west of central Mexico as it weakens to a trough as mentioned above. The pressure gradient between the ridge and lower pressure near the monsoon trough region will allow for moderate to locally fresh trade winds from about 12N to 19N and west of 125W, along with resultant seas in the range of 5 to 6 ft. Low pressure of 1010 mb is forecast to develop along the monsoon trough near 13N130W in about 24 hours or so. A second 1010 mb low pressure center is forecast to form near 12N137W in 24 hours also. The 13N130W low pressure center is expected to dissipate in 48 hours. The 12N137W low pressure center is expected to move near 12N139W in 48 hours. No significant organization is expected with either of these lows. The pressure gradient between the ridge and lower pressure near the monsoon trough region, including the aforementioned forecast lows, will allow for moderate to locally fresh trade winds from about 12N to 19N and west of 128W, along with resultant seas in the range of 5 to 6 ft. $$ Christensen