000 AXPZ20 KNHC 270909 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 909 UTC Sun Aug 27 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 0900 UTC. ..TROPICAL WAVES... A tropical wave is analyzed to the N of 12N along 97W moving W at 15 kt. Scattered moderate and isolated strong convection is N of 15N between 92W and 95W, including the Gulf of Tehuantepec, and also within 90 nm SW of Mexico between 97W and 103W. A tropical wave is analyzed from 12N114W to 19N111W moving W at 10 kt. Only isolated convection is present near the tropical wave axis. This tropical wave is likely to become less defined during the next couple of days. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 10N75W to 08N81W to 15N95W to 17N110W to low pressure near 12N116W to 12N130W to 10N140W. Scattered moderate to strong convection is from 01N to 08N and E of 82W, including the Gulf of Panama. Scattered moderate convection is from 09N to 11N between 128W and 131W. Scattered moderate and isolated strong convection is from 06N to 11N between 100W and 104W, due to a nearby mid to upper level trough. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A NW to SE oriented ridge extends across EPAC waters well beyond 250 nm. The resultant pressure gradient will support a moderate to locally fresh NW breeze across the open waters W of the Baja California Peninsula through early Mon, diminishing to gentle to moderate through the early part of the week. Expect 3 to 6 ft seas across this area. A weak cold front will move SE across Baja California Norte and the northern Gulf of California on Mon afternoon, stalling and dissipating along 28N late Mon night through midday on Tue. Expect only a light SW-W-NW wind shift with the front. A NW to SE oriented low level trough will meander from E to W across the Baja California Peninsula and adjacent Gulf of California through the next couple of days, with a surface low developing intermittently along the central portion of the trough. Light to gentle southerly flow in the Gulf of California will become light and variable tonight, with little change then expected through early Wed. Fresh to locally strong southwesterly monsoon flow and long period cross-equatorial swell, in the form 7 to 10 ft seas, will arrive across the waters S of 16N W of 98W tonight as developing low pressure currently near 15N105W shifts N and then NNW through the early part of the weak. This low is forecast to have the potential to develop into a tropical cyclone beyond 48 hours. At the very least, fresh to strong winds and seas of 8 to 10 ft will accompany the developing low, spreading across the offshore waters of Mexico S of 20N and W of 100W through early Tue, then toward the southern tip of the Baja California Peninsula, the entrance to the Gulf of California, and the Revillagigedo Islands Wed through Thu. In the Gulf of Tehuantepec, light northerly nocturnal drainage winds are forecast this week, with light to gentle onshore flow during the day. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, moderate to fresh nocturnal drainage flow is forecast tonight into early Mon. Otherwise, light and variable flow is expected N of the monsoon trough through the middle of the week, while moderate to locally fresh southerly winds are expected S of the monsoon trough. Long period southerly cross-equatorial swell in the form of 7 to 9 ft seas is currently breaching the equator. This swell will continue to propagate to the N, reaching along 06N by early Mon, then gradually subsiding through Tue. REMAINDER OF THE AREA... The remnant low of post-tropical cyclone Kenneth continues to spin near 29N135W. The estimated minimum central pressure is 1017 mb. A nearby buoy is reporting moderate winds and seas of 6 ft to the NE of the low, with moderate to fresh winds and seas to 7 ft likely on the NW side. The low is forecast to dissipate into a remnant trough between 24 and 48 hours. A ridge axis extends from 32N130W through 23N123W to to near 21N116W. Mainly moderate trades prevail N of the monsoon trough A of 120W, except locally fresh across the W central waters, supporting seas to 8 ft. These fresh winds will diminish tonight into early Mon allowing for seas to subside. Fresh to strong winds and seas of 7 to 10 ft are occurring S of the monsoon trough between 98W and 123W. These conditions will shift N today as surface low previously described above develops along the monsoon trough. $$ Lewitsky