000 AXPZ20 KNHC 110946 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Sep 11 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 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...TROPICAL WAVES AND TROPICAL LOWS... A tropical wave is analyzed from 10N109W to 21N109W with a 1010 mb surface low along the wave axis at 16N109W. The system has been moving W at 5 kt over the past 24 hours. Scattered moderate isolated strong convection is currently observed within 180 nm over the NW quadrant of the low. A 1011 mb low is embedded in the monsoon trough at 12.5N133W. Isolated moderate to strong convection is observed within 150 nm over the the N semicircle of the low. A tropical low is forecast to develop along the monsoon trough near 11N101W this afternoon, move NW to near 13N102W on Mon night, and near 15N105W on Tue night with strong winds developing initially over the SE semicircle. This low will continue NW towards the southern tip of the Baja Peninsula during the remainder of the week, with favorable environmental conditions for gradual strengthening. INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends SW off the coast of Guatemala at 14.5N92W through a tropical wave at 12N109W to 11N113W, then turns NW to 13N126W and through an embedded 1011 mb low pressure at 12.5N133W, then turns SW to beyond 10N140W. Scattered moderate isolated strong convection is noted within 180 nm either side of a line from 09N85W to 09N111W, within 120 nm either side of a line from 09N111W to 13.5N128W, and within 90 nm either side of a line from 13N91W to 16N102W to 22N106W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE oriented trough will meander across the Baja California Peninsula and the Gulf of California with a surface low developing intermittently along the trough axis over the far northern Gulf waters. A W to E orientated ridge will meander from 23N116W to 21N110W early this week with a moderate W to NW breeze is forecast across the EPAC waters S and W of the Baja California Peninsula through Wed afternoon, with 5 to 6 ft seas. Gulf of California...Light, mostly NW winds expected through Wed. Gulf of Tehuantepec: Strong to near gale force northerly flow is expected through early Tue, with seas building to 11 ft downstream of the gulf waters near 14.5N95.5W. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... The monsoon trough is expected to lift N this week with moderate to locally fresh southwesterly monsoonal flow expected S of the trough axis with 6 to 9 ft seas in cross-equatorial swell. These southerly swells with begin to subside on Tue night, with seas less than 8 ft on Fri night. REMAINDER OF THE AREA... A ridge extends from 32N137W to 23N116W with moderate anticyclonic flow expected N of the monsoon trough and W of 115W early this week. Fresh to locally strong SW monsoonal flow, and 8 to 13 ft seas, is forecast from 08N to 13N E of 114W today in long period cross- equatorial swell which will begin to subside on Tue night. $$ Nelson