000 AXPZ20 KNHC 100229 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0229 UTC Thu Aug 10 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 0215 UTC. ...TROPICAL WAVES... A tropical wave axis is along 91W/92W moving W at 10 to 15 kt. Convection is as described below. The interaction of energy associated with this tropical wave and the monsoon trough axis is forecast to gradually develop a broad cyclonic gyre over the far eastern part of the area to the SW of Central America by the end of the week and into the upcoming weekend. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 08N82W to 07N87W to low pressure near 13N106W to 10N128W to 12N140W. Scattered moderate and isolated strong convection is within 180 nm S of the axis E of 93W, within 210 nm of the coast of Central America between 83W and 90W, within 180 nm SE of the axis between 117W and 128W, from 05N to 09N between 130W and 136W, and from 11N to 14N between 131W and 140W. Scattered moderate convection is from 10N to 13N between 97W and 101W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... Ridging W of the Baja California peninsula and troughing along the Baja California peninsula is supporting moderate NW flow across the waters W of 110W, along with 4 to 5 ft seas. Mainly light to moderate onshore winds prevail elsewhere outside of the Gulf of California. Gentle to occasionally moderate southerly winds and seas of 2 ft or less prevail in the Gulf of California, except 3 to 4 ft near the entrance. Winds will become northerly in the southern Gulf by the end of the week. By Friday morning, weak low pressure may develop SW of Mexico between 100W and 106W. Fresh to strong E to SE winds will develop and parallel the coast within 60 nm building fresh seas to 8 ft. These conditions may then spread NW during the upcoming weekend along the coast dependent on the possible development of the low. Uncertainty remains with regards to the strength and impacts of any associated marine conditions. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Moderate southerly winds are expected S of the monsoon trough, with gentle and variable winds N of the monsoon trough. Seas are expected to be in the range of 4 to 6 ft. Long period southerly swell reaching the coastal areas of Costa Rica and Panama will decay through the end of the week. A new and extensive set of cross-equatorial swell is forecast by wave model guidance to cross 03.4S east of 120W, on Friday afternoon. This swell is forecast to reach the coastal waters of Panama and Costa Rica between 80W and 88W late on Sunday night, then from between El Salvador and Mexico by sunrise Monday. Seas will range from 7 to 10 feet across these offshore waters, except in the lee of the Galapagos Islands. REMAINDER OF THE AREA... A weak 1011 mb low pressure area is near 13N106W. Scattered moderate and isolated strong convection is within 240 nm in the NW quadrant of the low. This low is forecast gradually dissipate through tomorrow evening. Otherwise, a weak and broad ridge dominates the waters N of the convergence zone. Moderate trades and seas of 4 to 6 ft prevail N of the convergence zone under the ridging, with moderate to fresh southerly flow and 4 to 7 ft seas S of the convergence zone. Little overall change in these marine conditions is expected into the upcoming weekend. $$ Lewitsky