000 AXPZ20 KNHC 060945 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 1005 UTC Thu Jul 06 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... A tropical wave is analyzed to the N of 11N along 94W and has been moving W at 15 to 20 kt over the past 24 hours. Scattered strong convection has flared along and to the W of the wave within 45 nm either side of a line from 16N93W to 15.5N101W. Additionally clusters of tstms are observed over southern Guatemala, and across the eastern portion of Mexico to include the Yucatan Penisula. A tropical wave is analyzed from 07N108W to 16N108W and has moved W at about 15 kt over the past 24 hours. Scattered moderate and isolated strong convection is observed within 240 nm either side of a line 13N103W to 08N115W. There is a broad cyclonic circulation observed mainly to the E of the wave axis, and model guidance suggests that a surface low will develop along this wave near 10N later today. Environmental conditions are favorable for this future low to gradually strengthen. Please refer to the NHC Tropical Weather Outlook for the East Pacific at hurricanes.gov for more information. In the meantime, southerly monsoonal flow and long period cross-equatorial swell, results in a band of 7 to 9 ft seas 150 nm SE of a line from 10N103W to 07N109W. Expect fresh to locally strong cyclonic winds within about 420 nm E of the low in 24 hours. A tropical wave is analyzed from 12N120W to 21N120W with a weakening and exposed 1009 mb surface low at 18.5N121W. This system has been progressing W at 10 kt over the past 48 hours. Only scattered moderate convection is currently observed within 90 nm S of the low. This low appears to have missed the opportunity to strengthen, and expect it to dissipate within 36 hours, with the parent tropical wave continuing W and crossing 140W in about 96 hours. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough extends W off the Pacific coast of Costa Rica at 09N83W to 09N88W, then turns NW to 11N102W, then SW to 10N109W to 09N116W where it loses identity. Scatterometer data indicates that the monsoon trough resumes again near 11N122W, and continues SW to along 09.5N between 130W and 140W. Scattered moderate isolated strong convection is observed elsewhere along the monsoon trough within 90 nm either side of lines from 09N77W to 10N100W, and from 11.5N121W to 09N138W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE orientated ridge axis extends into the offshore waters along 23N116W to 16N100W. Gentle to locally moderate NW flow, with 3 to 5 ft seas, are forecast W of the Baja Penisula through early this afternoon. A tightening pressure gradient will result in a moderate to fresh NW breeze W of Baja tonight. The gradient will relax again on Fri. A weak trough will pass E through the waters W of Baja on Sat accompanied by a light SW-W- NW wind shift. Seas will build to 6 to 8 ft in N swell w of the trough, generally across the waters N of 29N W of 118W on Sat. Gulf of Tehuantepec...A band of scattered strong convection is currently observed with 45 nm either side of a line from 16N93W to 15.5N101W. Fresh to locally strong N-NE drainage flow is expected at sunrise this morning. Then fresh nocturnal flow expected through the upcoming weekend. Model guidance is suggesting a strong gap events will occur again on Sun night with seas building to 8 ft. Gulf of California...Dissipating convection over mainland Mexico may reach the E shore of the gulf waters from 23N to 29N throughout this morning. A surface low will develop intermittently over the far northern gulf waters along a N to S orientated thermal trough that meanders across the Baja Peninsula and gulf waters this week. A light to gentle, mostly southerly, breeze is expected this week except becoming a moderate to fresh S breeze on Sat. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... Gulf of Papagayo...Moderate to fresh nocturnal NE-E flow is expected through the upcoming weekend. Gentle to moderate southerly winds are forecast S of the monsoon trough which will extend E to W along roughly 09N. Long period SW swell in the form of 6 to 8 ft seas currently S of the equator, will begin to subside today. REMAINDER OF THE AREA... See special features and tropical wave paragraphs above. A N to S orientated trough extending from near 22N138W to 28N136W, will drift W today and pass W of 140W early Fri, all the while accompanied by a gentle NE to E to SE wind shift. A NW to SE orientated ridge will then rebuild across the area. $$ Nelson