000 AXPZ20 KNHC 030952 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Mon Jul 03 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 LOWS, WAVES AND TROUGHS... A tropical wave is analyzed to the N of 08N along 95W, and has been moving w at 12 kt over the past 24 hours. Scattered moderate to strong convection is observed within 90 nm either side of the wave and also inland across the Isthmus of Tehuantepec. A tropical wave is analyzed from 06N108W to 17N107W with a 1010 mb surface low along the wave near 12N108W. This system has been moving W at 5 to 10 kt over the past 24 hours. Scattered moderate isolated strong convection is currently observed within 120 nm either side of a line from 16N103W to 12N109W to 07N113W. Convection remains unorganized. Fresh southerly monsoonal flow is observed within 420 nm over the SE quadrant of the low with combined seas of 7 to 9 ft. The pressure gradient is forecast to relax as this low moves W-NW over the next few days accompanied by moderate cyclonic flow within 180 nm over the N semicircle. A 1011 mb low pressure center is quasi-stationary along the monsoon trough at 11N120W, with scattered moderate isolated strong convection flaring within 240 nm of the low. A surface trough is embedded in the ITCZ from 06N137W to 12N136W, with scattered moderate isolated strong convection observed to the N of 09N within 120 nm either side of the trough. A surface low is forecast to develop within the monsoon trough near 11N98W tonight and move generally W-NW on Tue and Wed reaching near 12N110W late Thu. Model guidance suggests this low will then quickly deepen, possibly assuming tropical cyclone characteristics. At the least, mariners should expect fresh monsoonal flow with 7 to 9 ft seas, across the tropical waters from 07N to 11N between 106W and 116W on Fri. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends SW across the Gulf of Panama from 08N78W to 07N82W, then turns NW through a tropical wave along 95W to 14N102W, then turns SW through a surface low at 12N108W, then continues SW through 12N115W, then turns W through a low pressure at 11N120W to 09N130W, where scatterometer winds indicate that the ITCZ develops, and continues W to a surface trough at 137W, resuming w of the trough and turning SW to beyond 08N140W. Except as mentioned in the tropical lows, waves and troughs paragraph above, scattered moderate isolated strong convection is observed N of 06N E of 80W, within 120 nm of 05N85W, and elsewhere within 120 nm either side of a line from 08N124W to 09N140W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE orientated ridge axis extends into the offshore waters along 21N116W to 18N103W. Gentle to locally moderate NW flow, with 3 to 5 ft seas, are forecast W of the Baja Penisula through late Tue. The pressure gradient will then tighten, with a moderate NW breeze W of Baja except increasing to a fresh breeze N of 27N within 60 nm of the coast during the late afternoons. Model guidance is suggesting that the pressure gradient will continue to tighten, with fresh NW winds to the N of 28N from late Fri into Sat. Moderate cyclonic flow is expected across the waters between 101W and 108W early this morning in association with a surface low S of the offshore waters. Gulf of Tehuantepec...Strong N-NE drainage flow will continue across the gulf waters to along 14N between 95W and 97W through late morning. Strong N flow will develop again each night this week. Model guidance is suggesting a significant gap event will occur late Fri night, with seas building to 9 ft downstream of the gulf waters near 15N95W. Gulf of California...A surface low will develop intermittently over the far northern gulf waters with a thermal trough meandering S from the low across the Baja Peninsula and gulf waters this week. A light to gentle, mostly southerly, breeze is expected this week. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Fresh to locally strong NE-E flow expected early this morning, then moderate to locally fresh nocturnal NE- E winds are then forecast this week with seas building to 6 ft. Gentle to moderate southerly winds forecast elsewhere early this week. Long period SW swell in the form of 7 to 9 ft seas, will reach along the equator on Wed night, and then begin to subside on Fri. REMAINDER OF THE AREA... See tropical lows,waves and troughs paragraph above. A NW to SE orientated ridge will extend across the area. Moderate to fresh NE winds are expected from 11N to 27N W of 128W today with small pockets of seas building briefly to 8 ft. A trough will develop from 12N134W to 29N130W on Tue, drift W on Wed and Thu passing 140W on Fri all the while accompanied by a gentle NE to E to SE wind shift. Long period southerly swell, in the form of 7-9 ft seas will cross the equator between 93W and 115W on Wed night, and reach along 10N on Fri. $$ Nelson